LXR 6.1/​testsuites/​fstests/​tftpfs/​init.c	Source navigation Diff markup Identifier search General search
	Version: 6.1 Revert   Change

File indexing completed on 2025-05-11 08:24:31

 /* SPDX-License-Identifier: BSD-2-Clause */
 
 /**
  * @file
  *
  * @ingroup RTEMSTestSuiteTestsTFTPFS
  *
  * @brief This source file contains the implementation of tests for libtftpfs.
  *
  * The tested source files are:
  *   + @ref tftpfs.c "tftpfs.c: TFTP file system"
  *   + @ref tftpDriver.c "tftpDriver.c: TFTP client library"
  * These tests focus on testing the UDP network interaction of libtftpfs.
  */
 
 /*
  * Copyright (C) 2022 embedded brains GmbH & Co. KG
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
  *    documentation and/or other materials provided with the distribution.
  *
  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  * POSSIBILITY OF SUCH DAMAGE.
  */
 
 #ifdef HAVE_CONFIG_H
 #include "config.h"
 #endif
 
 #include <stdio.h>
 #include <stdlib.h> /* malloc(), free() */
 #include <ctype.h> /* isprint() */
 #include <errno.h>
 #include <sys/stat.h> /* mkdir(), open() */
 #include <sys/types.h> /* mkdir(), open() */
 #include <sys/socket.h> /* AF_INET, SOCK_DGRAM */
 #include <fcntl.h> /* open() */
 #include <unistd.h> /* read(), close(), rmdir() */
 
 #include <rtems/tftp.h>
 #include <rtems/libio.h> /* mount(), RTEMS_FILESYSTEM_TYPE_TFTPFS */
 #include <rtems/test.h>
 #include <rtems/test-info.h>
 #include <rtems/testopts.h> /* RTEMS_TEST_VERBOSITY */
 #include <rtems.h>
 
 #include "tftpfs_udp_network_fake.h"
 #include "tftpfs_interactions.h"
 #include "tftp_driver.h"
 
 #define SERV_PORT 12345
 #define FIRST_TIMEOUT_MILLISECONDS  400
 #define TIMEOUT_MILLISECONDS        1000
 #define LARGE_BLOCK_SIZE            TFTP_BLOCK_SIZE_MAX
 #define SMALL_BLOCK_SIZE            12
 #define SMALL_WINDOW_SIZE           4
 #define T_no_more_interactions() T_assert_true( \
   _Tftp_Has_no_more_interactions(), \
   "The TFTP client skiped some final network interactions." \
 )
 
 /*
  * Test fixture and text context
  */
 
 typedef struct tftp_test_context {
   int fd0; /* File descriptor of a file read from or written to the tftpsfs */
   void *tftp_handle; /* TFTP client handle for this file transfer */
 } tftp_test_context;
 
 static const char *tftpfs_mount_point   = "/tftp";
 static const char *tftpfs_ipv4_loopback = TFTP_KNOWN_IPV4_ADDR0_STR;
 static const char *tftpfs_server0_name  = TFTP_KNOWN_SERVER0_NAME;
 static const char *tftpfs_server0_ipv4  = TFTP_KNOWN_SERVER0_IPV4;
 static const char *tftpfs_file          = "file.txt";
 static tftp_test_context tftp_context;
 
 static void mount_tftp_fs( const char *mount_point, const char *options )
 {
   int result;
 
   result = mkdir( mount_point, S_IRWXU | S_IRWXG | S_IRWXO );
   T_assert_eq_int( result, 0 );
 
   result = mount(
     "",
     mount_point,
     RTEMS_FILESYSTEM_TYPE_TFTPFS,
     RTEMS_FILESYSTEM_READ_WRITE,
     options
   );
   T_assert_eq_int( result, 0 );
 }
 
 static void umount_tftp_fs( const char *mount_point )
 {
   int result;
 
   result = unmount( mount_point );
   T_assert_eq_int( result, 0 );
 
   result = rmdir( mount_point );
   T_assert_eq_int( result, 0 );
 }
 
 static void setup_rfc1350( void *context )
 {
   tftp_test_context *ctx = context;
   _Tftp_Reset();
   ctx->fd0 = -1;
   ctx->tftp_handle = NULL;
   mount_tftp_fs( tftpfs_mount_point, "verbose,rfc1350" );
 }
 
 static void teardown( void *context )
 {
   tftp_test_context *ctx = context;
   if ( ctx->fd0 >= 0 ) {
     close( ctx->fd0 );
   }
   tftp_close( ctx->tftp_handle ); /* is a no-op if NULL */
   umount_tftp_fs( tftpfs_mount_point );
   _Tftp_Reset();
 }
 
 static const T_fixture fixture_rfc1350 = {
   .setup = setup_rfc1350,
   .stop = NULL,
   .teardown = teardown,
   .scope = NULL,
   .initial_context = &tftp_context
 };
 
 static void setup_default_options( void *context )
 {
   tftp_test_context *ctx = context;
   _Tftp_Reset();
   ctx->fd0 = -1;
   ctx->tftp_handle = NULL;
   mount_tftp_fs( tftpfs_mount_point, NULL );
 }
 
 static const T_fixture fixture_default_options = {
   .setup = setup_default_options,
   .stop = NULL,
   .teardown = teardown,
   .scope = NULL,
   .initial_context = &tftp_context
 };
 
 static void setup_large_blocksize( void *context )
 {
   tftp_test_context *ctx = context;
   _Tftp_Reset();
   ctx->fd0 = -1;
   ctx->tftp_handle = NULL;
   mount_tftp_fs(
     tftpfs_mount_point,
     "verbose,blocksize=" RTEMS_XSTRING(LARGE_BLOCK_SIZE) ",windowsize=1"
   );
 }
 
 static const T_fixture fixture_large_blocksize = {
   .setup = setup_large_blocksize,
   .stop = NULL,
   .teardown = teardown,
   .scope = NULL,
   .initial_context = &tftp_context
 };
 
 static void setup_small_opt_size( void *context )
 {
   tftp_test_context *ctx = context;
   _Tftp_Reset();
   ctx->fd0 = -1;
   ctx->tftp_handle = NULL;
   mount_tftp_fs(
     tftpfs_mount_point,
     "blocksize=" RTEMS_XSTRING(SMALL_BLOCK_SIZE)
     ",windowsize=" RTEMS_XSTRING(SMALL_WINDOW_SIZE)
   );
 }
 
 static const T_fixture fixture_small_opt_size = {
   .setup = setup_small_opt_size,
   .stop = NULL,
   .teardown = teardown,
   .scope = NULL,
   .initial_context = &tftp_context
 };
 
 static void setup_mount_point( void *context )
 {
   int result;
 
   _Tftp_Reset();
   result = mkdir( tftpfs_mount_point, S_IRWXU | S_IRWXG | S_IRWXO );
   T_assert_eq_int( result, 0 );
 }
 
 static void teardown_mount_point( void *context )
 {
   int result;
 
   result = rmdir( tftpfs_mount_point );
   T_assert_eq_int( result, 0 );
   _Tftp_Reset();
 }
 
 static const T_fixture fixture_mount_point = {
   .setup = setup_mount_point,
   .stop = NULL,
   .teardown = teardown_mount_point,
   .scope = NULL,
   .initial_context = &tftp_context
 };
 
 /*
  * Test helper functions
  */
 
 /*
  * Produce an artificial file content to be able to compare the
  * sent and the received file later on.
  */
 static uint8_t get_file_content( size_t pos )
 {
   static const size_t frame_size = 100;
   static const size_t num_size = 11;
   static const size_t alpha_size = 53;
   char buf[10];
   size_t remainder = pos % frame_size;
 
   switch ( remainder ) {
     case 0:
     case 1:
     case 2:
       sprintf( buf, "%9zu", pos - remainder );
       return buf[remainder];
     case 3:
     case 7:
       return '\'';
     case 4:
     case 5:
     case 6:
       sprintf( buf, "%9zu", pos - remainder );
       return buf[remainder-1];
     case 8:
     case 9:
     case 10:
       sprintf( buf, "%9zu", pos - remainder );
       return buf[remainder-2];
     default:
       pos -= ( pos / frame_size + 1 ) * num_size;
       remainder = pos % alpha_size;
       return ( remainder <= 'Z' - '@' ) ?
         remainder + '@' : remainder - ( 'Z' - '@' + 1) + 'a';
   }
 }
 
 /*
  * Produce bad file content.
  */
 static uint8_t get_bad_file_content( size_t pos )
 {
   static const char buf[] = "BAD!";
   return (uint8_t) buf[ pos % strlen( buf ) ];
 }
 
 static const char *create_tftpfs_path(
   const char *sever_addr,
   const char *file_name
 )
 {
   static char buffer[100];
   int len;
 
   len = snprintf(
     buffer,
     sizeof( buffer ),
     "%s/%s:%s",
     tftpfs_mount_point,
     sever_addr,
     file_name
   );
 
   T_quiet_gt_int( len, 0 );
   T_quiet_lt_int( len, (int) sizeof( buffer ) );
   return buffer;
 }
 
 static int read_tftp_file(
   const char *path,
   size_t buffer_size,
   size_t max_bytes,
   int *fd
 )
 {
   char *data_buffer;
   int result = 0;
   int res;
   ssize_t i;
   ssize_t bytes = 1;
   ssize_t bytes_total = 0;
   int errno_store;
 
   T_log( T_VERBOSE, "File system: open( %s, O_RDONLY )", path );
   errno = 0;
   *fd = open( path, O_RDONLY );
   errno_store = errno;
   T_log(
     T_VERBOSE,
     "File system: [open( %s, O_RDONLY )] = fd:%d (errno = %d)",
     path,
     *fd,
     errno
   );
 
   if ( *fd < 0 ) {
     /* open() may intentionally fail (e.g. test for invalid server address) */
     T_log( T_VERBOSE, "File system: cannot open \"%s\" for reading", path );
     errno = errno_store;
     result = -1;
   }
 
   if ( *fd >= 0 ) {
     data_buffer = malloc( buffer_size );
 
     while ( bytes > 0 && max_bytes >= bytes ) {
       errno = 0;
       bytes = read(
         *fd,
         data_buffer,
         ( max_bytes > buffer_size ) ? buffer_size : max_bytes
       );
       errno_store = errno;
       T_log(
         T_VERBOSE,
         "File system: [read( fd:%d, size=%zu )] = %zd (errno = %d)",
         *fd,
         ( max_bytes > buffer_size ) ? buffer_size : max_bytes,
         bytes,
         errno
       );
 
       if ( bytes > 0 ) {
         max_bytes -= bytes;
         for ( i = 0; i < bytes; ++i ) {
           if ( data_buffer[i] != get_file_content( bytes_total + i ) ) {
             T_true(
               false,
               "File system: wrong file content '%c' (expected '%c') "
                 "at position %zd",
               (int) ( isprint( (int) data_buffer[i] ) ? data_buffer[i] : '?' ),
               (int) get_file_content( bytes_total + i ),
               bytes_total + i
             );
             bytes = 0;
             break;
           }
         } /* for */
         bytes_total += bytes;
       }
       if ( bytes == 0 ) {
         result = (int) bytes_total;
       }
       if ( bytes < 0 ) {
         /* read() may intentionally fail (e.g. test lost network connection) */
         T_log(
           T_VERBOSE,
           "File system: error reading from \"%s\" after %zd bytes",
           path,
           bytes_total
         );
         result = (int) bytes_total;
       }
     } /* while */
 
     free( data_buffer );
   } /* if */
 
   if ( bytes > 0 ) {
     T_log(
       T_VERBOSE,
       "File system: reader closes \"%s\" after %zd bytes",
       path,
       bytes_total
     );
     result = (int) bytes_total;
   }
 
   if ( *fd >= 0 ) {
     res = close( *fd );
     T_log(
       T_VERBOSE,
       "File system: [close( %s (fd:%d) )] = %d",
       path,
       *fd,
       res
     );
     *fd = -1;
     T_eq_int( res, 0 );
   }
 
   errno = errno_store;
   return result;
 }
 
 static int write_tftp_file(
   const char *path,
   size_t file_size,
   size_t buffer_size,
   int *fd )
 {
   char *data_buffer;
   int result = 0;
   int res;
   ssize_t i;
   ssize_t bytes;
   ssize_t bytes_total = 0;
   int errno_store;
 
   errno = 0;
   T_log( T_VERBOSE, "File system: open( %s, O_WRONLY )", path );
   *fd = open( path, O_WRONLY );
   errno_store = errno;
   T_log(
     T_VERBOSE,
     "File system: [open( %s, O_WRONLY )] = fd:%d (errno = %d)",
     path,
     *fd,
     errno
   );
   if ( *fd < 0 ) {
     /* open() may intentionally fail (e.g. test for invalid server address) */
     T_log( T_VERBOSE, "File system: cannot open \"%s\" for writing", path );
     errno = errno_store;
     result = -1;
   }
 
   if ( *fd >= 0 ) {
     data_buffer = malloc( buffer_size );
 
     do { /* Try also to write files with 0 bytes size */
       bytes = ( file_size - bytes_total >= buffer_size ) ?
         buffer_size : file_size - bytes_total;
       for ( i = 0; i < bytes; ++i ) {
         data_buffer[i] = get_file_content( bytes_total + i );
       }
       errno = 0;
       bytes = write( *fd, data_buffer, i );
       errno_store = errno;
       T_log(
         T_VERBOSE,
         "File system: [write( fd:%d, size=%zd )] = %zd (errno = %d)",
         *fd,
         i,
         bytes,
         errno
       );
       if ( bytes > 0 ) {
         bytes_total += bytes;
         result = (int) bytes_total;
       }
       if ( bytes != i ) {
         /* write() may intentionally fail (e.g. test lost network connection) */
         T_log(
           T_VERBOSE,
           "File system: error writing to \"%s\" after %zd bytes",
           path,
           bytes_total
         );
         break;
       }
     } while( bytes_total < file_size );
 
     free( data_buffer );
   } /* if */
 
   if ( *fd >= 0 ) {
     res = close( *fd );
     if (res != 0) {
       errno_store = errno;
       result = res;
     }
     T_log(
       T_VERBOSE,
       "File system: [close( %s (fd:%d) )] = %d",
       path,
       *fd,
       res
     );
     *fd = -1;
   }
 
   errno = errno_store;
   return result;
 }
 
 static int rdwt_tftp_client_file(
   const char *hostname,
   const char *filename,
   bool is_for_reading,
   ssize_t file_size, /* Only used when `is_for_reading == false` */
   const tftp_net_config *config,
   void **tftp_handle
 )
 {
   const static size_t buffer_size = 4001;
   char *data_buffer;
   int res = 0;
   ssize_t i;
   ssize_t bytes = 1;
   ssize_t bytes_total = 0;
   int errno_store = 0;
 
   if ( *tftp_handle == NULL ) {
     T_log(
       T_VERBOSE,
       "TFTP Client: tftp_open( \"%s\", \"%s\", %s, ... )",
       hostname,
       filename,
       is_for_reading ? "read" : "write"
     );
     res = tftp_open(
       hostname,
       filename,
       is_for_reading,
       config,
       tftp_handle
     );
     T_log(
       T_VERBOSE,
       "TFTP Client: [tftp_open( \"%s\", \"%s\", %s, ... )] = %d (handle:%p)",
       hostname,
       filename,
       is_for_reading ? "read" : "write",
       res,
       *tftp_handle
     );
   } else {
     T_log(
       T_VERBOSE,
       "TFTP Client: \"%s\":\"%s\" already open for %s, handle: %p ",
       hostname,
       filename,
       is_for_reading ? "read" : "write",
       *tftp_handle
     );
   }
 
   if ( res != 0 ) {
     /* open() may intentionally fail (e.g. test for invalid server address) */
     T_log(
       T_VERBOSE,
       "TFTP client: cannot open \"%s\":\"%s\" for %s",
       hostname,
       filename,
       is_for_reading ? "reading" : "writing"
     );
     errno_store = res;
   } else {
     T_assert_not_null( *tftp_handle );
   }
 
   if ( *tftp_handle != NULL ) {
     data_buffer = malloc( buffer_size );
 
     if ( is_for_reading ) {
 
       /* Read file */
       while ( bytes > 0 ) {
         errno = 0;
         bytes = tftp_read(
           *tftp_handle,
           data_buffer,
           buffer_size
         );
         T_log(
           T_VERBOSE,
           "TFTP Client: [tftp_read( %p, size=%zu )] = %zd",
           *tftp_handle,
           buffer_size,
           bytes
         );
 
         if ( bytes > 0 ) {
           for ( i = 0; i < bytes; ++i ) {
             if ( data_buffer[i] != get_file_content( bytes_total + i ) ) {
               T_true(
                 false,
                 "FTP Client: wrong file content '%c' (expected '%c') at positon %zd",
                 (int) ( isprint( (int) data_buffer[i] ) ? data_buffer[i] : '?' ),
                 (int) get_file_content( bytes_total + i ),
                 bytes_total + i
               );
               bytes = 0;
               break;
             }
           } /* for */
           bytes_total += bytes;
         }
         if ( bytes < 0 ) {
           /* read() may intentionally fail (e.g. test lost network connection) */
           T_log(
             T_VERBOSE,
             "TFTP Client: error reading from \"%s\":\"%s\" after %zd bytes",
             hostname,
             filename,
             bytes_total
           );
           errno_store = -bytes;
         }
       } /* while */
     } else {
 
       /* Write file */
       do { /* Try also to write files with 0 bytes size */
         bytes = ( file_size - bytes_total >= buffer_size ) ?
           buffer_size : file_size - bytes_total;
         for ( i = 0; i < bytes; ++i ) {
           data_buffer[i] = get_file_content( bytes_total + i );
         }
         errno = 0;
         bytes = tftp_write( *tftp_handle, data_buffer, i );
         T_log(
           T_VERBOSE,
           "TFTP Client: [tftp_write( %p, size=%zd )] = %zd",
           *tftp_handle,
           i,
           bytes
         );
         if ( bytes > 0 ) {
           bytes_total += bytes;
         } else {
           errno_store = -bytes;
         }
         if ( bytes != i ) {
           /* write() may intentionally fail (e.g. test lost network connection) */
           T_log(
             T_VERBOSE,
             "TFTP Client: error writing to \"%s\":\"%s\" after %zd bytes",
             hostname,
             filename,
             bytes_total
           );
           break;
         }
       } while( bytes_total < file_size );
     } /* if ( is_for_reading ) */
 
     free( data_buffer );
   } /* if ( *tftp_handle != NULL ) */
 
   if ( *tftp_handle != NULL ) {
     res = tftp_close( *tftp_handle );
     T_log(
       T_VERBOSE,
       "TFTP Client: [tftp_close( \"%s\":\"%s\" (handle:%p) )] = %d",
       hostname,
       filename,
       *tftp_handle,
       res
     );
     *tftp_handle = NULL; /* Avoid that the fixture closes it again */
     T_eq_int( res, 0 );
   } /* if ( *tftp_handle != NULL ) */
 
   errno = errno_store;
   return (int) bytes_total;
 }
 
 /*
  * Unit test cases
  */
 
 /*
  * This is a classical unit test for the function tftp_initialize_net_config().
  * Tests:
  *   * tftp_initialize_net_config() sets correct default values as defined
  *     in the documentation of the data structures tftp_net_config
  *     and tftp_options.
  */
 T_TEST_CASE( tftp_initialize_net_config )
 {
   tftp_net_config config;
   memset( &config, 0, sizeof( config ) );
   tftp_initialize_net_config( &config );
   T_eq_u16( config.retransmissions, 6 );
   T_eq_u16( config.server_port, 69 );
   T_eq_u32( config.timeout, 1000 );
   T_eq_u32( config.first_timeout, 400 );
   T_eq_u16( config.options.block_size, 1456 );
   T_eq_u16( config.options.window_size, 8 );
 }
 
 /*
  * This is a classical unit test for the function tftp_initialize_net_config().
  * Tests:
  *   * tftp_initialize_net_config() does not crash when called with a
  *     NULL pointer.
  */
 T_TEST_CASE( tftp_initialize_net_config_null )
 {
   tftp_initialize_net_config( NULL );
 }
 
 /*
  * This is a classical unit test for the function tftp_open().
  * Tests:
  *   * tftp_open() returns an error when called with a NULL pointer
  *     for hostname.
  */
 T_TEST_CASE_FIXTURE( tftp_open_null_hostname, &fixture_rfc1350 )
 {
   tftp_test_context *ctx = T_fixture_context();
   int res;
 
   res = tftp_open(
     NULL, /* hostname */
     tftpfs_file,
     true, /* is_for_reading */
     NULL, /* config */
     &ctx->tftp_handle
   );
   T_eq_int( res, EINVAL );
   T_null( ctx->tftp_handle );
 }
 
 /*
  * This is a classical unit test for the function tftp_open().
  * Tests:
  *   * tftp_open() returns an error when called with a NULL pointer
  *     for filename.
  */
 T_TEST_CASE_FIXTURE( tftp_open_null_filename, &fixture_rfc1350 )
 {
   tftp_test_context *ctx = T_fixture_context();
   int res;
 
   res = tftp_open(
     tftpfs_ipv4_loopback,
     NULL, /* filename */
     true, /* is_for_reading */
     NULL, /* config */
     &ctx->tftp_handle
   );
   T_eq_int( res, EINVAL );
   T_null( ctx->tftp_handle );
 }
 
 /*
  * This is a classical unit test for the function tftp_open().
  * Tests:
  *   * tftp_open() returns an error when called with a NULL pointer
  *     for tftp_handle.
  */
 T_TEST_CASE( tftp_open_null_tftp_handle )
 {
   int res;
 
   res = tftp_open(
     tftpfs_ipv4_loopback,
     tftpfs_file,
     true, /* is_for_reading */
     NULL, /* config */
     NULL /* tftp_handle */
   );
   T_eq_int( res, EINVAL );
 }
 
 /*
  * This is a classical unit test for the function tftp_open().
  * Tests:
  *   * tftp_open() returns an error when called with value 0 for
  *     option window_size.
  */
 T_TEST_CASE_FIXTURE( tftp_open_illegal_window_size, &fixture_rfc1350 )
 {
   tftp_test_context *ctx = T_fixture_context();
   tftp_net_config config;
   int res;
 
   _Tftp_Add_interaction_socket( AF_INET, SOCK_DGRAM, 0, TFTP_FIRST_FD );
   _Tftp_Add_interaction_close( TFTP_FIRST_FD, 0 );
 
   tftp_initialize_net_config( &config );
   config.options.window_size = 1 - 1;
 
   res = tftp_open(
     tftpfs_ipv4_loopback,
     tftpfs_file,
     true, /* is_for_reading */
     &config,
     &ctx->tftp_handle
   );
   T_eq_int( res, EINVAL );
   T_null( ctx->tftp_handle );
   T_no_more_interactions();
 }
 
 /*
  * This is a classical unit test for the function tftp_open().
  * Tests:
  *   * tftp_open() returns an error when called with a too small
  *     value for option block_size.
  */
 T_TEST_CASE_FIXTURE( tftp_open_block_size_too_small, &fixture_rfc1350 )
 {
   tftp_test_context *ctx = T_fixture_context();
   tftp_net_config config;
   int res;
 
   _Tftp_Add_interaction_socket( AF_INET, SOCK_DGRAM, 0, TFTP_FIRST_FD );
   _Tftp_Add_interaction_close( TFTP_FIRST_FD, 0 );
 
   tftp_initialize_net_config( &config );
   config.options.block_size = 8 - 1;
 
   res = tftp_open(
     tftpfs_ipv4_loopback,
     tftpfs_file,
     true, /* is_for_reading */
     &config,
     &ctx->tftp_handle
   );
   T_eq_int( res, EINVAL );
   T_null( ctx->tftp_handle );
   T_no_more_interactions();
 }
 
 /*
  * This is a classical unit test for the function tftp_open().
  * Tests:
  *   * tftp_open() returns an error when called with a too large
  *     value for option block_size.
  */
 T_TEST_CASE_FIXTURE( tftp_open_block_size_too_large, &fixture_rfc1350 )
 {
   tftp_test_context *ctx = T_fixture_context();
   tftp_net_config config;
   int res;
 
   _Tftp_Add_interaction_socket( AF_INET, SOCK_DGRAM, 0, TFTP_FIRST_FD );
   _Tftp_Add_interaction_close( TFTP_FIRST_FD, 0 );
 
   tftp_initialize_net_config( &config );
   config.options.block_size = 65464 + 1;
 
   res = tftp_open(
     tftpfs_ipv4_loopback,
     tftpfs_file,
     false, /* is_for_reading */
     &config,
     &ctx->tftp_handle
   );
   T_eq_int( res, EINVAL );
   T_null( ctx->tftp_handle );
   T_no_more_interactions();
 }
 
 /*
  * This is a classical unit test for the function tftp_read().
  * Tests:
  *   * tftp_read() returns an error when called with a NULL pointer
  *     for tftp_handle.
  */
 T_TEST_CASE( tftp_read_null_tftp_handle )
 {
   char data_buffer[10];
   ssize_t res;
 
   res = tftp_read(
     NULL, /* tftp_handle */
     data_buffer,
     sizeof( data_buffer)
   );
   T_eq_int( res, -EIO );
 }
 
 /*
  * This is a classical unit test for the function tftp_read().
  * Tests:
  *   * tftp_read() returns an error when called with a NULL pointer
  *     for buffer.
  */
 T_TEST_CASE( tftp_read_null_buffer )
 {
   int tftp_handle;
   ssize_t res;
 
   res = tftp_read(
     &tftp_handle,
     NULL, /* buffer */
     8
   );
   T_eq_int( res, -EIO );
 }
 
 /*
  * This is a classical unit test for the function tftp_write().
  * Tests:
  *   * tftp_write() returns an error when called with a NULL pointer
  *     for tftp_handle.
  */
 T_TEST_CASE( tftp_write_null_tftp_handle )
 {
   char data_buffer[10] = { 0 };
   ssize_t res;
 
   res = tftp_write(
     NULL, /* tftp_handle */
     data_buffer,
     sizeof( data_buffer)
   );
   T_eq_int( res, -EIO );
 }
 
 /*
  * This is a classical unit test for the function tftp_write().
  * Tests:
  *   * tftp_write() returns an error when called with a NULL pointer
  *     for buffer.
  */
 T_TEST_CASE( tftp_write_null_buffer )
 {
   int tftp_handle;
   ssize_t res;
 
   res = tftp_write(
     &tftp_handle,
     NULL, /* buffer */
     8
   );
   T_eq_int( res, -EIO );
 }
 
 /*
  * This is a classical unit test for the function tftp_close().
  * Tests:
  *   * tftp_close() returns 0 when called with a NULL pointer.
  */
 T_TEST_CASE( tftp_close_null )
 {
   T_eq_int( tftp_close( NULL ), 0 );
 }
 
 /*
  * This is a classical unit test for the function _Tftpfs_Parse_options().
  * Tests:
  *   * Parsing an empty string has no effects.
  */
 T_TEST_CASE( _Tftpfs_Parse_options_empty )
 {
   size_t err_pos;
   uint32_t flags = 0;
   tftp_net_config config;
 
   tftp_initialize_net_config( &config );
   err_pos = _Tftpfs_Parse_options( "", &config, &flags );
   T_eq_sz( err_pos, 0 );
   T_eq_u16( config.options.block_size, TFTP_DEFAULT_BLOCK_SIZE );
   T_eq_u16( config.options.window_size, TFTP_DEFAULT_WINDOW_SIZE );
   T_eq_u32( flags, 0 );
 }
 
 /*
  * This is a classical unit test for the function _Tftpfs_Parse_options().
  * Tests:
  *   * Providing an NULL pointer instead of a string has no effect.
  */
 T_TEST_CASE( _Tftpfs_Parse_options_null )
 {
   size_t err_pos;
   uint32_t flags = 0;
   tftp_net_config config;
 
   tftp_initialize_net_config( &config );
   err_pos = _Tftpfs_Parse_options( NULL, &config, &flags );
   T_eq_sz( err_pos, 0 );
   T_eq_u16( config.options.block_size, TFTP_DEFAULT_BLOCK_SIZE );
   T_eq_u16( config.options.window_size, TFTP_DEFAULT_WINDOW_SIZE );
   T_eq_u32( flags, 0 );
 }
 
 /*
  * This is a classical unit test for the function _Tftpfs_Parse_options().
  * Tests:
  *   * Option "verbose" has the desired effect.
  */
 T_TEST_CASE( _Tftpfs_Parse_options_verbose )
 {
   size_t err_pos;
   uint32_t flags = 0;
   tftp_net_config config;
 
   tftp_initialize_net_config( &config );
   err_pos = _Tftpfs_Parse_options( "verbose", &config, &flags );
   T_eq_sz( err_pos, 0 );
   T_eq_u16( config.options.block_size, TFTP_DEFAULT_BLOCK_SIZE );
   T_eq_u16( config.options.window_size, TFTP_DEFAULT_WINDOW_SIZE );
   T_gt_u32( flags, 0 );
 }
 
 /*
  * This is a classical unit test for the function _Tftpfs_Parse_options().
  * Tests:
  *   * Option "rfc1350" has the desired effect.
  */
 T_TEST_CASE( _Tftpfs_Parse_options_rfc1350 )
 {
   size_t err_pos;
   uint32_t flags = 0;
   tftp_net_config config;
 
   tftp_initialize_net_config( &config );
   err_pos = _Tftpfs_Parse_options( "rfc1350", &config, &flags );
   T_eq_sz( err_pos, 0 );
   T_eq_u16( config.options.block_size, TFTP_RFC1350_BLOCK_SIZE );
   T_eq_u16( config.options.window_size, TFTP_RFC1350_WINDOW_SIZE );
   T_eq_u32( flags, 0 );
 }
 
 /*
  * This is a classical unit test for the function _Tftpfs_Parse_options().
  * Tests:
  *   * Option "blocksize" has the desired effect.
  */
 T_TEST_CASE( _Tftpfs_Parse_options_blocksize )
 {
   size_t err_pos;
   uint32_t flags = 0;
   tftp_net_config config;
 
   tftp_initialize_net_config( &config );
   err_pos = _Tftpfs_Parse_options( "blocksize=21", &config, &flags );
   T_eq_sz( err_pos, 0 );
   T_eq_u16( config.options.block_size, 21 );
   T_eq_u16( config.options.window_size, TFTP_DEFAULT_WINDOW_SIZE );
   T_eq_u32( flags, 0 );
 }
 
 /*
  * This is a classical unit test for the function _Tftpfs_Parse_options().
  * Tests:
  *   * Option "windowsize" has the desired effect.
  */
 T_TEST_CASE( _Tftpfs_Parse_options_windowsize )
 {
   size_t err_pos;
   uint32_t flags = 0;
   tftp_net_config config;
 
   tftp_initialize_net_config( &config );
   err_pos = _Tftpfs_Parse_options( "windowsize=13", &config, &flags );
   T_eq_sz( err_pos, 0 );
   T_eq_u16( config.options.block_size, TFTP_DEFAULT_BLOCK_SIZE );
   T_eq_u16( config.options.window_size, 13 );
   T_eq_u32( flags, 0 );
 }
 
 /*
  * This is a classical unit test for the function _Tftpfs_Parse_options().
  * Tests:
  *   * Processing of all options in one string works as expected.
  */
 T_TEST_CASE( _Tftpfs_Parse_options_all )
 {
   size_t err_pos;
   uint32_t flags = 0;
   tftp_net_config config;
 
   tftp_initialize_net_config( &config );
   err_pos = _Tftpfs_Parse_options( "rfc1350,blocksize=1234,windowsize=4567,verbose", &config, &flags );
   T_eq_sz( err_pos, 0 );
   T_eq_u16( config.options.block_size, 1234 );
   T_eq_u16( config.options.window_size, 4567 );
   T_gt_u32( flags, 0 );
 }
 
 /*
  * This is a classical unit test for the function _Tftpfs_Parse_options().
  * Tests:
  *   * Parser ignores unnecessary commas.
  */
 T_TEST_CASE( _Tftpfs_Parse_options_surplus_comma )
 {
   size_t err_pos;
   uint32_t flags = 0;
   tftp_net_config config;
 
   tftp_initialize_net_config( &config );
   err_pos = _Tftpfs_Parse_options( ",blocksize=1234,,,,windowsize=4567,,", &config, &flags );
   T_eq_sz( err_pos, 0 );
   T_eq_u16( config.options.block_size, 1234 );
   T_eq_u16( config.options.window_size, 4567 );
   T_eq_u32( flags, 0 );
 }
 
 /*
  * This is a classical unit test for the function _Tftpfs_Parse_options().
  * Tests:
  *   * Parser detects a bad value.
  */
 T_TEST_CASE( _Tftpfs_Parse_options_bad_value )
 {
   size_t err_pos;
   uint32_t flags = 0;
   tftp_net_config config;
 
   tftp_initialize_net_config( &config );
   err_pos = _Tftpfs_Parse_options( "blocksize=123.4,windowsize=4567", &config, &flags );
   T_eq_sz( err_pos, 14 );
 }
 
 /*
  * This is a classical unit test for the function _Tftpfs_Parse_options().
  * Tests:
  *   * Parser detects an illegal option.
  */
 T_TEST_CASE( _Tftpfs_Parse_options_illegal_option )
 {
   size_t err_pos;
   uint32_t flags = 0;
   tftp_net_config config;
 
   tftp_initialize_net_config( &config );
   err_pos = _Tftpfs_Parse_options( "blocksize=123,illegal", &config, &flags );
   T_eq_sz( err_pos, 15 );
 }
 
 /*
  * This is a classical unit test for the function _Tftpfs_Parse_options().
  * Tests:
  *   * Parser detects a truncated option.
  */
 T_TEST_CASE( _Tftpfs_Parse_options_truncated_option )
 {
   size_t err_pos;
   uint32_t flags = 0;
   tftp_net_config config;
 
   tftp_initialize_net_config( &config );
   err_pos = _Tftpfs_Parse_options( "blocksize", &config, &flags );
   T_eq_sz( err_pos, 1 );
 }
 
 /*
  * This is a classical unit test for the function rtems_tftpfs_initialize().
  * Tests:
  *   * Correct error handling in case mount options cannot be parsed.
  */
 T_TEST_CASE_FIXTURE( mount_with_bad_options, &fixture_mount_point )
 {
   int result;
 
   result = mount(
     "",
     tftpfs_mount_point,
     RTEMS_FILESYSTEM_TYPE_TFTPFS,
     RTEMS_FILESYSTEM_READ_WRITE,
     "windowsize=4567,blocksize=123bad"
   );
   T_assert_le_int( result, -1 );
   T_assert_eq_int( errno, EINVAL );
 }
 
 /*
  * Test cases for the TFTP client interface
  *
  * Since the TFTP file system uses the TFTP client interface for all
  * file transfers, the function of the TFTP client is almost
  * completely tested by the tests for the file system interface.
  * The test cases here - for the TFTP client interface - test only
  * those aspects not (easily) testable through the file system interface.
  */
 
 /*
  * Read a file from the server using the TFTP client interface.
  * The file is one byte long.  No timeouts, packet loss, ...
  * Tests:
  *   * tftp_open() called with NULL for config uses
  *     default configuration values.
  *   * Read a file using only the TFTP client (i.e. not using the
  *     file system)
  */
 T_TEST_CASE_FIXTURE( client_open_with_NULL_config, &fixture_rfc1350 )
 {
   tftp_test_context *ctx = T_fixture_context();
   int bytes_read;
   uint16_t block_num = 1;
   size_t pos_in_file = 0;
 
   /* T_set_verbosity( T_VERBOSE ); */
   _Tftp_Add_interaction_socket( AF_INET, SOCK_DGRAM, 0, TFTP_FIRST_FD );
   _Tftp_Add_interaction_send_rrq(
     TFTP_FIRST_FD,
     tftpfs_file,
     TFTP_STD_PORT,
     tftpfs_ipv4_loopback,
     TFTP_DEFAULT_BLOCK_SIZE,
     TFTP_DEFAULT_WINDOW_SIZE,
     true
   );
   _Tftp_Add_interaction_recv_data(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     block_num,
     pos_in_file,
     1, /* Number of bytes transferred */
     get_file_content,
     true
   );
   pos_in_file += 1;
   _Tftp_Add_interaction_send_ack(
     TFTP_FIRST_FD,
     block_num++,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     true
   );
   _Tftp_Add_interaction_close( TFTP_FIRST_FD, 0 );
 
   bytes_read = rdwt_tftp_client_file(
     tftpfs_ipv4_loopback,
     tftpfs_file,
     true, /* is_for_reading */
     -1, /* file_size for writing files only */
     NULL, /* config */
     &ctx->tftp_handle
   );
   T_eq_sz( bytes_read, pos_in_file );
   T_eq_int( errno, 0 );
   T_no_more_interactions();
 }
 
 /*
  * Read a very short file from the server using the TFTP client interface.
  * The file is one data packet long.  Use none-default configuration values.
  * The second and the third DATA packets are lost.  This causes
  * a termination of the connection because only two retransmissions are
  * configured.
  * Tests:
  *   * tftp_open() called with all configuration values having
  *     none default values.
  *   * The test writes a file using only the TFTP client (i.e. not using the
  *     file system API).
  *   * The client uses the none default configuration values:
  *     retransmissions, server_port, timeout, first_timeout,
  *     block_size, window_size.
  *   * The server sends the options in a different order than the client.
  *   * The option names in the OACK can be upper or lower case.
  *   * If windowsize > 1, the client sends ACK only each windowsize packet.
  *   * If windowsize > 1 and no packet is received in the timeout period,
  *     the client retransmits the last ACK.
  *   * The client makes a limited number of retransmissions attempts
  *     and then terminates the connections with an error.
  */
 T_TEST_CASE_FIXTURE( client_open_with_none_default_config, &fixture_rfc1350 )
 {
   tftp_test_context *ctx = T_fixture_context();
   tftp_net_config config;
   int bytes_read;
   uint16_t block_num = 0;
   size_t pos_in_file = 0;
   uint16_t retransmissions = 2;
   uint16_t server_port = 3456;
   uint32_t timeout = 300;
   uint32_t first_timeout = 200;
   uint16_t block_size = 8;
   uint16_t window_size = 2;
   const char options[] =
     "WINDOWSIZE" "\0" "2\0"
     TFTP_OPTION_BLKSIZE "\0" "8";
 
   /* T_set_verbosity( T_VERBOSE ); */
   _Tftp_Add_interaction_socket( AF_INET, SOCK_DGRAM, 0, TFTP_FIRST_FD );
   _Tftp_Add_interaction_send_rrq(
     TFTP_FIRST_FD,
     tftpfs_file,
     server_port,
     tftpfs_ipv4_loopback,
     block_size,
     window_size,
     true
   );
   _Tftp_Add_interaction_recv_oack(
     TFTP_FIRST_FD,
     first_timeout,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     options,
     sizeof( options ),
     true
   );
   _Tftp_Add_interaction_send_ack(
     TFTP_FIRST_FD,
     block_num++,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     true
   );
   _Tftp_Add_interaction_recv_data(
     TFTP_FIRST_FD,
     first_timeout,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     block_num++,
     pos_in_file,
     block_size, /* Number of bytes transferred */
     get_file_content,
     true
   );
   pos_in_file += TFTP_RFC1350_BLOCK_SIZE;
   _Tftp_Add_interaction_recv_data(
     TFTP_FIRST_FD,
     first_timeout,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     block_num,
     pos_in_file,
     block_size, /* Number of bytes transferred */
     get_file_content,
     true
   );
   pos_in_file += TFTP_RFC1350_BLOCK_SIZE;
   _Tftp_Add_interaction_send_ack(
     TFTP_FIRST_FD,
     block_num++,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     true
   );
   _Tftp_Add_interaction_recv_nothing(
     TFTP_FIRST_FD,
     first_timeout /* Timeout: No packet received within timeout period */
   );
   _Tftp_Add_interaction_send_ack(
     TFTP_FIRST_FD,
     block_num - 1, /* Block number OK: Last block successfully received */
     SERV_PORT,
     tftpfs_ipv4_loopback,
     true
   );
   _Tftp_Add_interaction_recv_nothing(
     TFTP_FIRST_FD,
     timeout /* Timeout: No packet received within timeout period */
   );
   _Tftp_Add_interaction_send_error(
     TFTP_FIRST_FD,
     TFTP_ERROR_CODE_NO_USER,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     true
   );
   _Tftp_Add_interaction_close( TFTP_FIRST_FD, 0 );
 
   tftp_initialize_net_config( &config );
   config.retransmissions = retransmissions;
   config.server_port = server_port;
   config.timeout = timeout;
   config.first_timeout = first_timeout;
   config.options.block_size = block_size;
   config.options.window_size = window_size;
 
   bytes_read = rdwt_tftp_client_file(
     tftpfs_ipv4_loopback,
     tftpfs_file,
     true, /* is_for_reading */
     -1, /* file_size for writing files only */
     &config,
     &ctx->tftp_handle
   );
 
   /*
    * Not a bug but not nice: The client has received data before the connection
    * breaks down due to timeout and this data is not provided to the user.
    */
 
   T_eq_sz( bytes_read, 0 );
   T_eq_int( errno, EIO );
   T_no_more_interactions();
 }
 
 /*
  * Attempt to write to a file open for reading using the TFTP client interface.
  * Tests:
  *   * tftp_open() called with NULL for config uses
  *     default configuration values.
  *   * Read a file using only the TFTP client (i.e. not using the
  *     file system)
  *   * The attempt to write to a file open for reading is rejected
  *     with an error.
  *   * The server receives an error message to indicate that the client
  *     closes the connection without having transferred data.
  */
 T_TEST_CASE_FIXTURE( client_write_to_file_opened_for_reading, &fixture_rfc1350 )
 {
   tftp_test_context *ctx = T_fixture_context();
   int res = 0;
   const char options[] =
     TFTP_OPTION_BLKSIZE "\0"
     RTEMS_XSTRING( TFTP_DEFAULT_BLOCK_SIZE ) "\0"
     TFTP_OPTION_WINDOWSIZE"\0"
     RTEMS_XSTRING( TFTP_DEFAULT_WINDOW_SIZE );
 
   /* T_set_verbosity( T_VERBOSE ); */
   _Tftp_Add_interaction_socket( AF_INET, SOCK_DGRAM, 0, TFTP_FIRST_FD );
   _Tftp_Add_interaction_send_rrq(
     TFTP_FIRST_FD,
     tftpfs_file,
     TFTP_STD_PORT,
     tftpfs_ipv4_loopback,
     TFTP_DEFAULT_BLOCK_SIZE,
     TFTP_DEFAULT_WINDOW_SIZE,
     true
   );
   _Tftp_Add_interaction_recv_oack(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     options,
     sizeof( options ),
     true
   );
   /* Sending an ACK at this place before the ERROR would be OK, too. */
   _Tftp_Add_interaction_send_error(
     TFTP_FIRST_FD,
     TFTP_ERROR_CODE_NO_USER,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     true
   );
   _Tftp_Add_interaction_close( TFTP_FIRST_FD, 0 );
 
   res = tftp_open(
     tftpfs_ipv4_loopback,
     tftpfs_file,
     true, /* is_for_reading */
     NULL, /* Config */
     &ctx->tftp_handle
   );
   T_eq_int( res, 0 );
   T_assert_not_null( ctx->tftp_handle );
 
   res = (int) tftp_write( ctx->tftp_handle, &res, 1 );
   T_eq_int( res, -EIO );
 
   res = tftp_close( ctx->tftp_handle );
   ctx->tftp_handle = NULL; /* Avoid that the fixture closes it again */
   T_eq_int( res, 0 );
   T_no_more_interactions();
 }
 
 /*
  * Attempt to read from a file open for writing using the TFTP client
  * interface.
  * Tests:
  *   * tftp_open() called with NULL for config uses
  *     default configuration values.
  *   * Read a file using only the TFTP client (i.e. not using the
  *     file system)
  *   * Attempt to read from a file open for writing is rejected with an error.
  */
 T_TEST_CASE_FIXTURE( client_read_to_file_opened_for_writing, &fixture_rfc1350 )
 {
   tftp_test_context *ctx = T_fixture_context();
   int res = 0;
   uint16_t block_num = 1;
   size_t pos_in_file = 0;
   const char options[] =
     TFTP_OPTION_BLKSIZE "\0"
     RTEMS_XSTRING( TFTP_DEFAULT_BLOCK_SIZE ) "\0"
     TFTP_OPTION_WINDOWSIZE"\0"
     RTEMS_XSTRING( TFTP_DEFAULT_WINDOW_SIZE );
 
   /* T_set_verbosity( T_VERBOSE ); */
   _Tftp_Add_interaction_socket( AF_INET, SOCK_DGRAM, 0, TFTP_FIRST_FD );
   _Tftp_Add_interaction_send_wrq(
     TFTP_FIRST_FD,
     tftpfs_file,
     TFTP_STD_PORT,
     tftpfs_ipv4_loopback,
     TFTP_DEFAULT_BLOCK_SIZE,
     TFTP_DEFAULT_WINDOW_SIZE,
     true
   );
   _Tftp_Add_interaction_recv_oack(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     options,
     sizeof( options ),
     true
   );
   _Tftp_Add_interaction_send_data(
     TFTP_FIRST_FD,
     block_num,
     pos_in_file,
     0, /* Data size */
     get_file_content,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     true
   );
   pos_in_file += 0;
   _Tftp_Add_interaction_recv_ack(
      TFTP_FIRST_FD,
      FIRST_TIMEOUT_MILLISECONDS,
      SERV_PORT,
      tftpfs_ipv4_loopback,
      block_num++,
      true
    );
   _Tftp_Add_interaction_close( TFTP_FIRST_FD, 0 );
 
   res = tftp_open(
     tftpfs_ipv4_loopback,
     tftpfs_file,
     false, /* is_for_reading */
     NULL, /* config */
     &ctx->tftp_handle
   );
   T_eq_int( res, 0 );
   T_assert_not_null( ctx->tftp_handle );
 
   res = (int) tftp_read( ctx->tftp_handle, &res, 1 );
   T_eq_int( res, -EIO );
 
   res = tftp_close( ctx->tftp_handle );
   ctx->tftp_handle = NULL; /* Avoid that the fixture closes it again */
   T_eq_int( res, 0 );
   T_no_more_interactions();
 }
 
 /*
  * Write a file to the server using the TFTP client interface.
  * The test uses the default options.
  * The file is 2 and a half data packet long.  No timeouts, packet loss, ...
  * Tests:
  *   * The default options (windowsize = 8 and blocksize = 1456) are used.
  *   * tftp_open() is called with default configuration values.
  *   * The test writes a file using only the TFTP client (i.e. not using the
  *     file system)
  *   * The code supports the use of a server name instead of an IP address.
  *   * The first window is also the last window.
  *   * The only ACK packet is the one at the end of window.
  *   * Between sending data packets, the client checks whether any packets
  *     are received.
  *   * The client handles files correctly which end in the middle of a window.
  */
 T_TEST_CASE_FIXTURE( client_write_simple_file, &fixture_default_options )
 {
   tftp_test_context *ctx = T_fixture_context();
   tftp_net_config config;
   int bytes_written;
   uint16_t block_num = 1;
   size_t pos_in_file = 0;
   const char options[] =
     TFTP_OPTION_BLKSIZE "\0"
     RTEMS_XSTRING( TFTP_DEFAULT_BLOCK_SIZE ) "\0"
     TFTP_OPTION_WINDOWSIZE "\0"
     RTEMS_XSTRING( TFTP_DEFAULT_WINDOW_SIZE );
 
   /* T_set_verbosity( T_VERBOSE ); */
   _Tftp_Add_interaction_socket( AF_INET, SOCK_DGRAM, 0, TFTP_FIRST_FD );
   _Tftp_Add_interaction_send_wrq(
     TFTP_FIRST_FD,
     tftpfs_file,
     TFTP_STD_PORT,
     tftpfs_server0_ipv4,
     TFTP_DEFAULT_BLOCK_SIZE,
     TFTP_DEFAULT_WINDOW_SIZE,
     true
   );
   _Tftp_Add_interaction_recv_oack(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_server0_ipv4,
     options,
     sizeof( options ),
     true
   );
   _Tftp_Add_interaction_send_data(
     TFTP_FIRST_FD,
     block_num++,
     pos_in_file,
     TFTP_DEFAULT_BLOCK_SIZE,
     get_file_content,
     SERV_PORT,
     tftpfs_server0_ipv4,
     true
   );
   pos_in_file += TFTP_DEFAULT_BLOCK_SIZE;
   _Tftp_Add_interaction_recv_nothing(
     TFTP_FIRST_FD,
     DO_NOT_WAIT_FOR_ANY_TIMEOUT
   );
   _Tftp_Add_interaction_send_data(
     TFTP_FIRST_FD,
     block_num++,
     pos_in_file,
     TFTP_DEFAULT_BLOCK_SIZE,
     get_file_content,
     SERV_PORT,
     tftpfs_server0_ipv4,
     true
   );
   pos_in_file += TFTP_DEFAULT_BLOCK_SIZE;
   _Tftp_Add_interaction_recv_nothing(
     TFTP_FIRST_FD,
     DO_NOT_WAIT_FOR_ANY_TIMEOUT
   );
   _Tftp_Add_interaction_send_data(
     TFTP_FIRST_FD,
     block_num,
     pos_in_file,
     TFTP_DEFAULT_BLOCK_SIZE / 2, /* Data bytes in this block */
     get_file_content,
     SERV_PORT,
     tftpfs_server0_ipv4,
     true
   );
   pos_in_file += TFTP_DEFAULT_BLOCK_SIZE / 2;
   _Tftp_Add_interaction_recv_ack(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_server0_ipv4,
     block_num++,
     true
   );
   _Tftp_Add_interaction_close( TFTP_FIRST_FD, 0 );
 
   tftp_initialize_net_config( &config );
   bytes_written = rdwt_tftp_client_file(
     tftpfs_server0_name,
     tftpfs_file,
     false, /* is_for_reading */
     pos_in_file, /* file_size for writing files only */
     &config,
     &ctx->tftp_handle
   );
   T_eq_sz( bytes_written, pos_in_file );
   T_eq_int( errno, 0 );
   T_no_more_interactions();
 }
 
 /*
  * Test cases for the file system interface
  */
 
 /*
  * Read a file from the server using only RFC1350.
  * The file is two and a half data packet long.  No timeouts, packet loss, ...
  * Tests:
  *   * The code supports requests without options (RFC1350 only).
  *   * The code supports the use of an IPv4 address instead of a server name.
  *   * The first packet is sent to standard port 69 of server.
  *   * All other packets are sent to the port used for this connection.
  *   * The first and second data packet are full.
  *   * The third data packet signals the end of transfer.
  *   * Read the file from file system in one big chunk of exactly
  *     the size of the file.
  */
 T_TEST_CASE_FIXTURE( read_simple_file, &fixture_rfc1350 )
 {
   tftp_test_context *ctx = T_fixture_context();
   int bytes_read;
   uint16_t block_num = 1;
   size_t pos_in_file = 0;
 
   /* T_set_verbosity( T_VERBOSE ); */
   _Tftp_Add_interaction_socket( AF_INET, SOCK_DGRAM, 0, TFTP_FIRST_FD );
   _Tftp_Add_interaction_send_rrq(
     TFTP_FIRST_FD,
     tftpfs_file,
     TFTP_STD_PORT,
     tftpfs_ipv4_loopback,
     NO_BLOCK_SIZE_OPTION,
     NO_WINDOW_SIZE_OPTION,
     true
   );
   _Tftp_Add_interaction_recv_data(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     block_num,
     pos_in_file,
     TFTP_RFC1350_BLOCK_SIZE, /* Number of bytes transferred */
     get_file_content,
     true
   );
   pos_in_file += TFTP_RFC1350_BLOCK_SIZE;
   _Tftp_Add_interaction_send_ack(
     TFTP_FIRST_FD,
     block_num++,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     true
   );
   _Tftp_Add_interaction_recv_data(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     block_num,
     pos_in_file,
     TFTP_RFC1350_BLOCK_SIZE, /* Number of bytes transferred */
     get_file_content,
     true
   );
   pos_in_file += TFTP_RFC1350_BLOCK_SIZE;
   _Tftp_Add_interaction_send_ack(
     TFTP_FIRST_FD,
     block_num++,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     true
   );
   _Tftp_Add_interaction_recv_data(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     block_num,
     pos_in_file,
     TFTP_RFC1350_BLOCK_SIZE / 2, /* Number of bytes transferred */
     get_file_content,
     true
   );
   pos_in_file += TFTP_RFC1350_BLOCK_SIZE / 2;
   _Tftp_Add_interaction_send_ack(
     TFTP_FIRST_FD,
     block_num++,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     true
   );
   _Tftp_Add_interaction_close( TFTP_FIRST_FD, 0 );
 
   bytes_read = read_tftp_file(
     create_tftpfs_path( tftpfs_ipv4_loopback, tftpfs_file ),
     /* Bytes read per call to read() */
     2 * TFTP_RFC1350_BLOCK_SIZE + TFTP_RFC1350_BLOCK_SIZE / 2,
     SIZE_MAX,
     &ctx->fd0
   );
   T_eq_int( bytes_read, pos_in_file );
   T_no_more_interactions();
 }
 
 /*
  * Read a file from the server using only RFC1350.
  * The file is one byte long.  No timeouts, packet loss, ...
  * Tests:
  *   * The code supports requests without options (RFC1350 only).
  *   * The code supports the use of an IPv4 address instead of a server name.
  *   * The first packet is sent to standard port 69 of server.
  *   * All other packets are sent to the port used for this connection.
  *   * The first data packet is not full and signals the end of the transfer.
  *   * The test reads a file from the file system in one-byte chunks.
  */
 T_TEST_CASE_FIXTURE( read_tiny_file, &fixture_rfc1350 )
 {
   tftp_test_context *ctx = T_fixture_context();
   int bytes_read;
   uint16_t block_num = 1;
   size_t pos_in_file = 0;
 
   /* T_set_verbosity( T_VERBOSE ); */
   _Tftp_Add_interaction_socket( AF_INET, SOCK_DGRAM, 0, TFTP_FIRST_FD );
   _Tftp_Add_interaction_send_rrq(
     TFTP_FIRST_FD,
     tftpfs_file,
     TFTP_STD_PORT,
     tftpfs_ipv4_loopback,
     NO_BLOCK_SIZE_OPTION,
     NO_WINDOW_SIZE_OPTION,
     true
   );
   _Tftp_Add_interaction_recv_data(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     block_num,
     pos_in_file,
     1, /* Number of bytes transferred */
     get_file_content,
     true
   );
   pos_in_file += 1;
   _Tftp_Add_interaction_send_ack(
     TFTP_FIRST_FD,
     block_num++,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     true
   );
   _Tftp_Add_interaction_close( TFTP_FIRST_FD, 0 );
 
   bytes_read = read_tftp_file(
     create_tftpfs_path( tftpfs_ipv4_loopback, tftpfs_file ),
     1, /* Bytes read per call to read() */
     SIZE_MAX,
     &ctx->fd0
   );
   T_eq_int( bytes_read, pos_in_file );
   T_no_more_interactions();
 }
 
 /*
  * Read a file from the server using only RFC1350.
  * The file is one data packet long.  No timeouts, packet loss, ...
  * Tests:
  *   * The code supports requests without options (RFC1350 only).
  *   * The code supports the use of an IPv4 address instead of a server name.
  *   * The first packet is sent to standard port 69 of server.
  *   * All other packets are sent to the port used for this connection.
  *   * The first data packet is full.
  *   * The second data packet is empty and signals the end of the transfer.
  *   * The client handles an empty data packet correctly as end
  *     of file indicator.
  *   * The test reads a file from the file system in chunks of three quarters
  *     of the block size.
  */
 T_TEST_CASE_FIXTURE( read_one_block_file, &fixture_rfc1350 )
 {
   tftp_test_context *ctx = T_fixture_context();
   int bytes_read;
   uint16_t block_num = 1;
   size_t pos_in_file = 0;
 
   /* T_set_verbosity( T_VERBOSE ); */
   _Tftp_Add_interaction_socket( AF_INET, SOCK_DGRAM, 0, TFTP_FIRST_FD );
   _Tftp_Add_interaction_send_rrq(
     TFTP_FIRST_FD,
     tftpfs_file,
     TFTP_STD_PORT,
     tftpfs_ipv4_loopback,
     NO_BLOCK_SIZE_OPTION,
     NO_WINDOW_SIZE_OPTION,
     true
   );
   _Tftp_Add_interaction_recv_data(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     block_num,
     pos_in_file,
     TFTP_RFC1350_BLOCK_SIZE, /* Number of bytes transferred */
     get_file_content,
     true
   );
   pos_in_file += TFTP_RFC1350_BLOCK_SIZE;
   _Tftp_Add_interaction_send_ack(
     TFTP_FIRST_FD,
     block_num++,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     true
   );
   _Tftp_Add_interaction_recv_data(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     block_num,
     pos_in_file,
     0, /* Number of bytes transferred */
     get_file_content,
     true
   );
   _Tftp_Add_interaction_send_ack(
     TFTP_FIRST_FD,
     block_num++,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     true
   );
   _Tftp_Add_interaction_close( TFTP_FIRST_FD, 0 );
 
   bytes_read = read_tftp_file(
     create_tftpfs_path( tftpfs_ipv4_loopback, tftpfs_file ),
     /* Bytes read per call to read() */
     TFTP_RFC1350_BLOCK_SIZE / 4 * 3,
     SIZE_MAX,
     &ctx->fd0
   );
   T_eq_int( bytes_read, pos_in_file );
   T_no_more_interactions();
 }
 
 /*
  * Read a file from the server using only RFC1350.
  * The file is one data packet long.
  * The client receives stray packets:
  *   * A packet from an unknown server (wrong TID)
  *   * An ACK packet instead of a DATA packet
  * Tests:
  *   * The code supports requests without options (RFC1350 only).
  *   * The code supports the use of an IPv4 address instead of a server name.
  *   * The first packet is sent to standard port 69 of server.
  *   * All other packets are sent to the port used for this connection.
  *   * The first data packet is full.
  *   * The next received packet originates from a wrong TID
  *     (i.e. wrong connection).
  *   * Upon reception of a packet with a wrong TID, the client sends
  *     an ERROR message with code 5 and does not terminate the current
  *     transfer.
  *   * The final received packet is an ACK packet instead or the expected
  *     DATA packet.
  *   * Upon the reception of an unexpected packet, the client terminates
  *     the connection by sending an error packet to the server.
  */
 T_TEST_CASE_FIXTURE( read_file_stray_packets, &fixture_rfc1350 )
 {
   tftp_test_context *ctx = T_fixture_context();
   int bytes_read;
   uint16_t block_num = 1;
   size_t pos_in_file = 0;
 
   /* T_set_verbosity( T_VERBOSE ); */
   _Tftp_Add_interaction_socket( AF_INET, SOCK_DGRAM, 0, TFTP_FIRST_FD );
   _Tftp_Add_interaction_send_rrq(
     TFTP_FIRST_FD,
     tftpfs_file,
     TFTP_STD_PORT,
     tftpfs_ipv4_loopback,
     NO_BLOCK_SIZE_OPTION,
     NO_WINDOW_SIZE_OPTION,
     true
   );
   _Tftp_Add_interaction_recv_data(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     block_num,
     pos_in_file,
     TFTP_RFC1350_BLOCK_SIZE, /* Number of bytes transferred */
     get_file_content,
     true
   );
   pos_in_file += TFTP_RFC1350_BLOCK_SIZE;
   _Tftp_Add_interaction_send_ack(
     TFTP_FIRST_FD,
     block_num++,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     true
   );
   _Tftp_Add_interaction_recv_data(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT + 1, /* Stray packet with wrong server TID */
     tftpfs_ipv4_loopback,
     block_num,
     pos_in_file,
     TFTP_RFC1350_BLOCK_SIZE, /* Number of bytes transferred */
     get_file_content,
     true
   );
   _Tftp_Add_interaction_send_error(
     TFTP_FIRST_FD,
     TFTP_ERROR_CODE_UNKNOWN_ID,
     SERV_PORT + 1,
     tftpfs_ipv4_loopback,
     true
   );
   _Tftp_Add_interaction_recv_ack( /* Stray ACK packet */
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     block_num - 1,
     true
   );
   _Tftp_Add_interaction_send_error(
     TFTP_FIRST_FD,
     TFTP_ERROR_CODE_ILLEGAL,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     true
   );
   _Tftp_Add_interaction_close( TFTP_FIRST_FD, 0 );
 
   bytes_read = read_tftp_file(
     create_tftpfs_path( tftpfs_ipv4_loopback, tftpfs_file ),
     /* Bytes read per call to read() */
     TFTP_RFC1350_BLOCK_SIZE / 4 * 3,
     SIZE_MAX,
     &ctx->fd0
   );
   T_eq_int( errno, EPROTO );
   /*
    * The client received one packet with TFTP_RFC1350_BLOCK_SIZE
    * before the error occurred.  The test reads in chunks of
    * TFTP_RFC1350_BLOCK_SIZE /4 * 3.  Thus, after the first chunk
    * the client signals the error to the test.
    *
    * It would be a little improvement if the client would return all
    * bytes received before signaling the error.
    */
   T_eq_int( bytes_read, TFTP_RFC1350_BLOCK_SIZE / 4 * 3 );
   T_no_more_interactions();
 }
 
 /*
  * Read a file from the server using only RFC1350.
  * The file is one data packet long.
  * The server sends an error message after the first DATA packet.
  * Tests:
  *   * The code supports requests without options (RFC1350 only).
  *   * The code supports the use of an IPv4 address instead of a server name.
  *   * The first packet is sent to standard port 69 of server.
  *   * All other packets are sent to the port used for this connection.
  *   * The client uses a short time out for all packets.
  *   * The client handles error packets from the server and stops the
  *     connection by signaling an error to the user on the file system side.
  *   * The test reads a file from the file system in chunks of three quarters
  *     of the block size.
  */
 T_TEST_CASE_FIXTURE( read_one_block_file_server_error, &fixture_rfc1350 )
 {
   tftp_test_context *ctx = T_fixture_context();
   int bytes_read;
   uint16_t block_num = 1;
   size_t pos_in_file = 0;
 
   /* T_set_verbosity( T_VERBOSE ); */
   _Tftp_Add_interaction_socket( AF_INET, SOCK_DGRAM, 0, TFTP_FIRST_FD );
   _Tftp_Add_interaction_send_rrq(
     TFTP_FIRST_FD,
     tftpfs_file,
     TFTP_STD_PORT,
     tftpfs_ipv4_loopback,
     NO_BLOCK_SIZE_OPTION,
     NO_WINDOW_SIZE_OPTION,
     true
   );
   _Tftp_Add_interaction_recv_data(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     block_num,
     pos_in_file,
     TFTP_RFC1350_BLOCK_SIZE, /* Number of bytes transferred */
     get_file_content,
     true
   );
   pos_in_file += TFTP_RFC1350_BLOCK_SIZE;
   _Tftp_Add_interaction_send_ack(
     TFTP_FIRST_FD,
     block_num++,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     true
   );
   _Tftp_Add_interaction_recv_error(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     TFTP_ERROR_CODE_NO_ACCESS,
     "Cannot read more",
     true
   );
   _Tftp_Add_interaction_close( TFTP_FIRST_FD, 0 );
 
   bytes_read = read_tftp_file(
     create_tftpfs_path( tftpfs_ipv4_loopback, tftpfs_file ),
     /* Bytes read per call to read() */
     TFTP_RFC1350_BLOCK_SIZE / 4 * 3,
     SIZE_MAX,
     &ctx->fd0
   );
   T_eq_int( bytes_read, TFTP_RFC1350_BLOCK_SIZE / 4 * 3 );
   T_eq_int( errno, EPERM );
   T_no_more_interactions();
 }
 
 /*
  * Read a file from the server using only RFC1350.
  * The file is one data packet long.
  * The server sends a malformed error packet after the first DATA packet.
  * The error message in the packet is not a 0 terminated string
  * Tests:
  *   * The code supports requests without options (RFC1350 only).
  *   * The code supports the use of an IPv4 address instead of a server name.
  *   * The first packet is sent to standard port 69 of server.
  *   * All other packets are sent to the port used for this connection.
  *   * The client handles malformed errors from the server and does not crash.
  *   * The test reads a file from the file system in chunks of three quarters
  *     of the block size.
  */
 T_TEST_CASE_FIXTURE( read_one_block_file_malformed_server_error, &fixture_rfc1350 )
 {
   tftp_test_context *ctx = T_fixture_context();
   int bytes_read;
   uint16_t block_num = 1;
   size_t pos_in_file = 0;
   static const uint8_t packet_malformed_error[] = {
   0x00, 0x05, /* Opcode = TFTP_OPCODE_ERROR */
   0x00, 0x02, /* Error code = TFTP_ERROR_CODE_NO_ACCESS */
   'n', 'o', ' ', 'a', 'c', 'c', 'e', 's', 's' /* missing '\0' at the end */
   };
 
   /* T_set_verbosity( T_VERBOSE ); */
   _Tftp_Add_interaction_socket( AF_INET, SOCK_DGRAM, 0, TFTP_FIRST_FD );
   _Tftp_Add_interaction_send_rrq(
     TFTP_FIRST_FD,
     tftpfs_file,
     TFTP_STD_PORT,
     tftpfs_ipv4_loopback,
     NO_BLOCK_SIZE_OPTION,
     NO_WINDOW_SIZE_OPTION,
     true
   );
   _Tftp_Add_interaction_recv_data(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     block_num,
     pos_in_file,
     TFTP_RFC1350_BLOCK_SIZE, /* Number of bytes transferred */
     get_file_content,
     true
   );
   pos_in_file += TFTP_RFC1350_BLOCK_SIZE;
   _Tftp_Add_interaction_send_ack(
     TFTP_FIRST_FD,
     block_num++,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     true
   );
   _Tftp_Add_interaction_recv_raw(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     sizeof( packet_malformed_error ), /* Malformed ERROR packet */
     packet_malformed_error,
     true
   );
   _Tftp_Add_interaction_close( TFTP_FIRST_FD, 0 );
 
   bytes_read = read_tftp_file(
     create_tftpfs_path( tftpfs_ipv4_loopback, tftpfs_file ),
     /* Bytes read per call to read() */
     TFTP_RFC1350_BLOCK_SIZE / 4 * 3,
     SIZE_MAX,
     &ctx->fd0
   );
   T_eq_int( bytes_read, TFTP_RFC1350_BLOCK_SIZE / 4 * 3 );
   T_eq_int( errno, EPERM );
   T_no_more_interactions();
 }
 
 /*
  * Read a file from the server using only RFC1350.
  * The reader on the file system side stops after having read half a
  * data packet and before having received the whole file and closes the file.
  * Tests:
  *   * The code supports requests without options (RFC1350 only).
  *   * The code supports the use of an IPv4 address instead of a server name.
  *   * The first packet is sent to standard port 69 of server.
  *   * All other packets are sent to the port used for this connection.
  *   * The first data packet is full.
  *   * The client handles the closing of the file by the user correctly.
  *   * The client sends an error to the server after the user stops reading
  *     the file.
  *   * The test reads a file from the file system in chunks of block size.
  */
 T_TEST_CASE_FIXTURE( read_one_block_close_file, &fixture_rfc1350 )
 {
   tftp_test_context *ctx = T_fixture_context();
   int bytes_read;
   uint16_t block_num = 1;
   size_t pos_in_file = 0;
 
   /* T_set_verbosity( T_VERBOSE ); */
   _Tftp_Add_interaction_socket( AF_INET, SOCK_DGRAM, 0, TFTP_FIRST_FD );
   _Tftp_Add_interaction_send_rrq(
     TFTP_FIRST_FD,
     tftpfs_file,
     TFTP_STD_PORT,
     tftpfs_ipv4_loopback,
     NO_BLOCK_SIZE_OPTION,
     NO_WINDOW_SIZE_OPTION,
     true
   );
   _Tftp_Add_interaction_recv_data(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     block_num,
     pos_in_file,
     TFTP_RFC1350_BLOCK_SIZE, /* Number of bytes transferred */
     get_file_content,
     true
   );
   /* Sending an ACK at this place before the ERROR would be OK, too. */
   _Tftp_Add_interaction_send_error(
     TFTP_FIRST_FD,
     TFTP_ERROR_CODE_NO_USER,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     true
   );
   _Tftp_Add_interaction_close( TFTP_FIRST_FD, 0 );
 
   bytes_read = read_tftp_file(
     create_tftpfs_path( tftpfs_ipv4_loopback, tftpfs_file ),
     TFTP_RFC1350_BLOCK_SIZE / 4, /* Bytes read per call to read() */
     TFTP_RFC1350_BLOCK_SIZE / 2, /* Max bytes read from this file */
     &ctx->fd0
   );
   T_eq_int( bytes_read, TFTP_RFC1350_BLOCK_SIZE / 2 );
   T_no_more_interactions();
 }
 
 /*
  * Read a file from the server using only RFC1350.
  * The reader on the file system side just open()s and then immediately closes
  * the file without ever reading a single byte.
  * Tests:
  *   * The code supports requests without options (RFC1350 only).
  *   * The code supports the use of an IPv4 address instead of a server name.
  *   * The first packet is sent to standard port 69 of server.
  *   * All other packets are sent to the port used for this connection.
  *   * The first data packet is full.
  *   * The client handles the closing of the file by the user correctly.
  *   * The client sends an error to the server when the user closes the file.
  */
 T_TEST_CASE_FIXTURE( read_close_file_immediately, &fixture_rfc1350 )
 {
   tftp_test_context *ctx = T_fixture_context();
   int bytes_read;
   uint16_t block_num = 1;
   size_t pos_in_file = 0;
 
   /* T_set_verbosity( T_VERBOSE ); */
   _Tftp_Add_interaction_socket( AF_INET, SOCK_DGRAM, 0, TFTP_FIRST_FD );
   _Tftp_Add_interaction_send_rrq(
     TFTP_FIRST_FD,
     tftpfs_file,
     TFTP_STD_PORT,
     tftpfs_ipv4_loopback,
     NO_BLOCK_SIZE_OPTION,
     NO_WINDOW_SIZE_OPTION,
     true
   );
   _Tftp_Add_interaction_recv_data(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     block_num,
     pos_in_file,
     TFTP_RFC1350_BLOCK_SIZE, /* Number of bytes transferred */
     get_file_content,
     true
   );
   /* Sending an ACK at this place before the ERROR would be OK, too. */
   _Tftp_Add_interaction_send_error(
     TFTP_FIRST_FD,
     TFTP_ERROR_CODE_NO_USER,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     true
   );
   _Tftp_Add_interaction_close( TFTP_FIRST_FD, 0 );
 
   bytes_read = read_tftp_file(
     create_tftpfs_path( tftpfs_ipv4_loopback, tftpfs_file ),
     TFTP_RFC1350_BLOCK_SIZE / 4, /* Bytes read per call to read() */
     0, /* Max bytes read from this file */
     &ctx->fd0
   );
   T_eq_int( bytes_read, 0 );
   T_no_more_interactions();
 }
 
 /*
  * Read an empty file from the server using only RFC1350.
  * No timeouts, packet loss, ...
  * Tests:
  *   * The code supports requests without options (RFC1350 only).
  *   * The code supports the use of a server name instead of an IP address.
  *   * The first packet is sent to standard port 69 of server.
  *   * All other packets are sent to the port used for this connection.
  *   * The client uses a short time out for all packets.
  *   * The first data packet has length 0.
  *   * The client can read empty files from the server.
  *   * The test reads a file from the file system in one big chunk which
  *     is larger than the file.
  */
 T_TEST_CASE_FIXTURE( read_empty_file, &fixture_rfc1350 )
 {
   tftp_test_context *ctx = T_fixture_context();
   int bytes_read;
   uint16_t block_num = 1;
   size_t pos_in_file = 0;
 
   /* T_set_verbosity( T_VERBOSE ); */
   _Tftp_Add_interaction_socket( AF_INET, SOCK_DGRAM, 0, TFTP_FIRST_FD );
   _Tftp_Add_interaction_send_rrq(
     TFTP_FIRST_FD,
     tftpfs_file,
     TFTP_STD_PORT,
     tftpfs_server0_ipv4,
     NO_BLOCK_SIZE_OPTION,
     NO_WINDOW_SIZE_OPTION,
     true
   );
   _Tftp_Add_interaction_recv_data(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_server0_ipv4,
     block_num,
     pos_in_file,
     0, /* Number of bytes transferred */
     get_file_content,
     true
   );
   _Tftp_Add_interaction_send_ack(
     TFTP_FIRST_FD,
     block_num++,
     SERV_PORT,
     tftpfs_server0_ipv4,
     true
   );
   _Tftp_Add_interaction_close( TFTP_FIRST_FD, 0 );
 
   bytes_read = read_tftp_file(
     create_tftpfs_path( tftpfs_server0_name, tftpfs_file ),
     /* Bytes read per call to read() */
     TFTP_RFC1350_BLOCK_SIZE,
     SIZE_MAX,
     &ctx->fd0
   );
   T_assert_eq_int( bytes_read, pos_in_file );
   T_no_more_interactions();
 }
 
 /*
  * Read an empty file from the server using only RFC1350.
  * The first two RRQ packets are lost.
  * Tests:
  *   * The code supports requests without options (RFC1350 only).
  *   * The code supports the use of a server name instead of an IP address.
  *   * The first packet is sent to standard port 69 of server.
  *   * The client uses a short time out for first packets.
  *   * The client uses a longer time out for repeated packets.
  *   * The client repeats lost RRQs packets.
  *   * The client does not repeat the ACK packet for the last DATA packet
  *     which signals the end of transfer.
  *   * The first data packet is empty and signals the end of the transfer.
  *   * It is possible to read a file with 0 bytes content from
  *     the file system.
  */
 T_TEST_CASE_FIXTURE( read_empty_file_looing_rrq, &fixture_rfc1350 )
 {
   tftp_test_context *ctx = T_fixture_context();
   int bytes_read;
   uint16_t block_num = 1;
   size_t pos_in_file = 0;
 
   /* T_set_verbosity( T_VERBOSE ); */
   _Tftp_Add_interaction_socket( AF_INET, SOCK_DGRAM, 0, TFTP_FIRST_FD );
   _Tftp_Add_interaction_send_rrq(
     TFTP_FIRST_FD,
     tftpfs_file,
     TFTP_STD_PORT,
     tftpfs_server0_ipv4,
     NO_BLOCK_SIZE_OPTION,
     NO_WINDOW_SIZE_OPTION,
     true
   );
   _Tftp_Add_interaction_recv_nothing(
     TFTP_FIRST_FD, /* Timeout: No packet received within timeout period */
     FIRST_TIMEOUT_MILLISECONDS
   );
   _Tftp_Add_interaction_send_rrq(
     TFTP_FIRST_FD,
     tftpfs_file,
     TFTP_STD_PORT,
     tftpfs_server0_ipv4,
     NO_BLOCK_SIZE_OPTION,
     NO_WINDOW_SIZE_OPTION,
     true
   );
   _Tftp_Add_interaction_recv_nothing(
     TFTP_FIRST_FD, /* Timeout: No packet received within timeout period */
     TIMEOUT_MILLISECONDS
   );
   _Tftp_Add_interaction_send_rrq(
     TFTP_FIRST_FD,
     tftpfs_file,
     TFTP_STD_PORT,
     tftpfs_server0_ipv4,
     NO_BLOCK_SIZE_OPTION,
     NO_WINDOW_SIZE_OPTION,
     true
   );
   _Tftp_Add_interaction_recv_data(
     TFTP_FIRST_FD,
     TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_server0_ipv4,
     block_num,
     pos_in_file,
     0, /* Number of bytes transferred */
     get_file_content,
     true
   );
   _Tftp_Add_interaction_send_ack(
     TFTP_FIRST_FD,
     block_num++,
     SERV_PORT,
     tftpfs_server0_ipv4,
     true
   );
   _Tftp_Add_interaction_close( TFTP_FIRST_FD, 0 );
 
   bytes_read = read_tftp_file(
     create_tftpfs_path( tftpfs_server0_name, tftpfs_file ),
     /* Bytes read per call to read() */
     TFTP_RFC1350_BLOCK_SIZE,
     SIZE_MAX,
     &ctx->fd0
   );
   T_assert_eq_int( bytes_read, pos_in_file );
   T_no_more_interactions();
 }
 
 /*
  * Read a file from the server using only RFC1350.
  * The file is one and a half data packet long.
  * Two data packet are lost (timeout) and the client must repeat the ACK.
  * Tests:
  *   * The code supports requests without options (RFC1350 only).
  *   * The code supports the use of an IPv4 address instead of a server name.
  *   * The first packet is sent to standard port 69 of server.
  *   * The client uses a short time out for first packets.
  *   * The client uses a longer time out for repeated packets.
  *   * The client repeats the ACK packets which are supposed
  *     to be lost.
  *   * The client does not repeat the ACK packet for the last DATA packet
  *     which signals the end of transfer.
  *   * The test reads a file in chunks of 17 bytes from file system.
  */
 T_TEST_CASE_FIXTURE( read_small_file_lost_packets, &fixture_rfc1350 )
 {
   tftp_test_context *ctx = T_fixture_context();
   int bytes_read;
   uint16_t block_num = 1;
   size_t pos_in_file = 0;
 
   /* T_set_verbosity( T_VERBOSE ); */
   _Tftp_Add_interaction_socket( AF_INET, SOCK_DGRAM, 0, TFTP_FIRST_FD );
   _Tftp_Add_interaction_send_rrq(
     TFTP_FIRST_FD,
     tftpfs_file,
     TFTP_STD_PORT,
     tftpfs_ipv4_loopback,
     NO_BLOCK_SIZE_OPTION,
     NO_WINDOW_SIZE_OPTION,
     true
   );
   _Tftp_Add_interaction_recv_data(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     block_num,
     pos_in_file,
     TFTP_RFC1350_BLOCK_SIZE, /* Number of bytes transferred */
     get_file_content,
     true
   );
   pos_in_file += TFTP_RFC1350_BLOCK_SIZE;
   _Tftp_Add_interaction_send_ack(
     TFTP_FIRST_FD,
     block_num,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     true
   );
   _Tftp_Add_interaction_recv_nothing(
     TFTP_FIRST_FD, /* Timeout: No packet received within timeout period */
     FIRST_TIMEOUT_MILLISECONDS
   );
   _Tftp_Add_interaction_send_ack(
     TFTP_FIRST_FD,
     block_num,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     true
   );
   _Tftp_Add_interaction_recv_nothing(
     TFTP_FIRST_FD, /* Timeout: No packet received within timeout period */
     TIMEOUT_MILLISECONDS
   );
   _Tftp_Add_interaction_send_ack(
     TFTP_FIRST_FD,
     block_num++,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     true
   );
   _Tftp_Add_interaction_recv_data(
     TFTP_FIRST_FD,
     TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     block_num,
     pos_in_file,
     TFTP_RFC1350_BLOCK_SIZE / 2, /* Number of bytes transferred */
     get_file_content,
     true
   );
   pos_in_file += TFTP_RFC1350_BLOCK_SIZE / 2;
   _Tftp_Add_interaction_send_ack(
     TFTP_FIRST_FD,
     block_num++,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     true
   );
   _Tftp_Add_interaction_close( TFTP_FIRST_FD, 0 );
 
   bytes_read = read_tftp_file(
     create_tftpfs_path( tftpfs_ipv4_loopback, tftpfs_file ),
     17, /* Bytes read per call to read() */
     SIZE_MAX,
     &ctx->fd0
   );
   T_eq_int( bytes_read, pos_in_file );
   T_no_more_interactions();
 }
 
 /*
  * Read a file from the server using only RFC1350.
  * The file is exactly one data packet long.
  * The client receives a malformed DATA packet (wrong op code).
  * Tests:
  *   * The code supports requests without options (RFC1350 only).
  *   * The code supports the use of an IPv4 address instead of a server name.
  *   * The first packet is sent to standard port 69 of server.
  *   * All other packets are sent to the port used for this connection.
  *   * The client uses a short time out for all packets.
  *   * The first data packet is full.
  *   * The client terminates the connection with an error message upon
  *     reception of a malformed packet.
  */
 T_TEST_CASE_FIXTURE( read_small_file_malformed_packet_1, &fixture_rfc1350 )
 {
   tftp_test_context *ctx = T_fixture_context();
   int bytes_read;
   uint16_t block_num = 1;
   size_t pos_in_file = 0;
   static const uint8_t packet_illegal_opcode_1[] = { 0x00, 0xFF, 0x00, 0x00 };
 
   /* T_set_verbosity( T_VERBOSE ); */
   _Tftp_Add_interaction_socket( AF_INET, SOCK_DGRAM, 0, TFTP_FIRST_FD );
   _Tftp_Add_interaction_send_rrq(
     TFTP_FIRST_FD,
     tftpfs_file,
     TFTP_STD_PORT,
     tftpfs_ipv4_loopback,
     NO_BLOCK_SIZE_OPTION,
     NO_WINDOW_SIZE_OPTION,
     true
   );
   _Tftp_Add_interaction_recv_data(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     block_num,
     pos_in_file,
     TFTP_RFC1350_BLOCK_SIZE, /* Number of bytes transferred */
     get_file_content,
     true
   );
   pos_in_file += TFTP_RFC1350_BLOCK_SIZE;
   _Tftp_Add_interaction_send_ack(
     TFTP_FIRST_FD,
     block_num,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     true
   );
   _Tftp_Add_interaction_recv_raw(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     sizeof( packet_illegal_opcode_1 ), /* Malformed DATA packet */
     packet_illegal_opcode_1,
     true
   );
   _Tftp_Add_interaction_send_error(
     TFTP_FIRST_FD,
     TFTP_ERROR_CODE_ILLEGAL,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     true
   );
   _Tftp_Add_interaction_close( TFTP_FIRST_FD, 0 );
 
   bytes_read = read_tftp_file(
     create_tftpfs_path( tftpfs_ipv4_loopback, tftpfs_file ),
     TFTP_RFC1350_BLOCK_SIZE / 4, /* Bytes read per call to read() */
     SIZE_MAX,
     &ctx->fd0
   );
   T_eq_int( bytes_read, pos_in_file );
   T_eq_int( errno, EPROTO );
   T_no_more_interactions();
 }
 
 /*
  * Read a file from the server using only RFC1350.
  * The file is exactly one data packet long.
  * The client receives a malformed DATA packet (wrong op code).
  * Tests:
  *   * The code supports requests without options (RFC1350 only).
  *   * The code supports the use of an IPv4 address instead of a server name.
  *   * The first packet is sent to standard port 69 of server.
  *   * All other packets are sent to the port used for this connection.
  *   * The first data packet is full.
  *   * The second data packet is malformed.
  *   * The client terminates the connection with an error message upon
  *     reception of a malformed packet.
  */
 T_TEST_CASE_FIXTURE( read_small_file_malformed_packet_2, &fixture_rfc1350 )
 {
   tftp_test_context *ctx = T_fixture_context();
   int bytes_read;
   uint16_t block_num = 1;
   size_t pos_in_file = 0;
   static const uint8_t packet_illegal_opcode_2[] = { 0x03, 0x00, 0x00, 0x01 };
 
   /* T_set_verbosity( T_VERBOSE ); */
   _Tftp_Add_interaction_socket( AF_INET, SOCK_DGRAM, 0, TFTP_FIRST_FD );
   _Tftp_Add_interaction_send_rrq(
     TFTP_FIRST_FD,
     tftpfs_file,
     TFTP_STD_PORT,
     tftpfs_ipv4_loopback,
     NO_BLOCK_SIZE_OPTION,
     NO_WINDOW_SIZE_OPTION,
     true
   );
   _Tftp_Add_interaction_recv_data(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     block_num,
     pos_in_file,
     TFTP_RFC1350_BLOCK_SIZE, /* Number of bytes transferred */
     get_file_content,
     true
   );
   pos_in_file += TFTP_RFC1350_BLOCK_SIZE;
   _Tftp_Add_interaction_send_ack(
     TFTP_FIRST_FD,
     block_num,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     true
   );
   _Tftp_Add_interaction_recv_raw(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     sizeof( packet_illegal_opcode_2 ), /* Malformed DATA packet */
     packet_illegal_opcode_2,
     true
   );
   _Tftp_Add_interaction_send_error(
     TFTP_FIRST_FD,
     TFTP_ERROR_CODE_ILLEGAL,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     true
   );
   _Tftp_Add_interaction_close( TFTP_FIRST_FD, 0 );
 
   bytes_read = read_tftp_file(
     create_tftpfs_path( tftpfs_ipv4_loopback, tftpfs_file ),
     TFTP_RFC1350_BLOCK_SIZE / 4, /* Bytes read per call to read() */
     SIZE_MAX,
     &ctx->fd0
   );
   T_eq_int( bytes_read, pos_in_file );
   T_eq_int( errno, EPROTO );
   T_no_more_interactions();
 }
 
 /*
  * Read a file from the server using only RFC1350.
  * The file is exactly one data packet long.
  * The client receives a malformed packet.
  * Tests:
  *   * The code supports requests without options (RFC1350 only).
  *   * The code supports the use of an IPv4 address instead of a server name.
  *   * The first packet is sent to standard port 69 of server.
  *   * All other packets are sent to the port used for this connection.
  *   * The first DATA packet received after the RRQ packet is malformed.
  *     It is too short with only one byte length.
  *   * The client sends an error and terminates the file transfer upon
  *     reception of a malformed packet.
  */
 T_TEST_CASE_FIXTURE( read_file_malformed_ack_1, &fixture_rfc1350 )
 {
   tftp_test_context *ctx = T_fixture_context();
   int bytes_read;
   size_t pos_in_file = 0;
   static const uint8_t packet_too_short_1[] = { 0x03 };
 
   /* T_set_verbosity( T_VERBOSE ); */
   _Tftp_Add_interaction_socket( AF_INET, SOCK_DGRAM, 0, TFTP_FIRST_FD );
   _Tftp_Add_interaction_send_rrq(
     TFTP_FIRST_FD,
     tftpfs_file,
     TFTP_STD_PORT,
     tftpfs_ipv4_loopback,
     NO_BLOCK_SIZE_OPTION,
     NO_WINDOW_SIZE_OPTION,
     true
   );
   _Tftp_Add_interaction_recv_raw(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     sizeof( packet_too_short_1 ), /* Malformed DATA packet */
     packet_too_short_1,
     true
   );
   _Tftp_Add_interaction_send_error(
     TFTP_FIRST_FD,
     TFTP_ERROR_CODE_ILLEGAL,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     true
   );
   _Tftp_Add_interaction_close( TFTP_FIRST_FD, 0 );
 
   bytes_read = read_tftp_file(
     create_tftpfs_path( tftpfs_ipv4_loopback, tftpfs_file ),
     TFTP_RFC1350_BLOCK_SIZE / 4, /* Bytes read per call to read() */
     SIZE_MAX,
     &ctx->fd0
   );
   T_eq_int( bytes_read, pos_in_file );
   T_eq_int( errno, EPROTO );
   T_no_more_interactions();
 }
 
 /*
  * Read a file from the server using only RFC1350.
  * The file is exactly one data packet long.
  * The client receives a malformed packet.
  * Tests:
  *   * The code supports requests without options (RFC1350 only).
  *   * The code supports the use of an IPv4 address instead of a server name.
  *   * The first packet is sent to standard port 69 of server.
  *   * All other packets are sent to the port used for this connection.
  *   * The first DATA packet received after the RRQ packet is malformed.
  *     It is too short with only two bytes length.
  *   * The client sends an error and terminates the file transfer upon
  *     reception of a malformed packet.
  */
 T_TEST_CASE_FIXTURE( read_file_malformed_ack_2, &fixture_rfc1350 )
 {
   tftp_test_context *ctx = T_fixture_context();
   int bytes_read;
   size_t pos_in_file = 0;
   static const uint8_t packet_too_short_2[] = { 0x00, 0x03 };
 
   /* T_set_verbosity( T_VERBOSE ); */
   _Tftp_Add_interaction_socket( AF_INET, SOCK_DGRAM, 0, TFTP_FIRST_FD );
   _Tftp_Add_interaction_send_rrq(
     TFTP_FIRST_FD,
     tftpfs_file,
     TFTP_STD_PORT,
     tftpfs_ipv4_loopback,
     NO_BLOCK_SIZE_OPTION,
     NO_WINDOW_SIZE_OPTION,
     true
   );
   _Tftp_Add_interaction_recv_raw(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     sizeof( packet_too_short_2 ), /* Malformed DATA packet */
     packet_too_short_2,
     true
   );
   _Tftp_Add_interaction_send_error(
     TFTP_FIRST_FD,
     TFTP_ERROR_CODE_ILLEGAL,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     true
   );
   _Tftp_Add_interaction_close( TFTP_FIRST_FD, 0 );
 
   bytes_read = read_tftp_file(
     create_tftpfs_path( tftpfs_ipv4_loopback, tftpfs_file ),
     TFTP_RFC1350_BLOCK_SIZE / 4, /* Bytes read per call to read() */
     SIZE_MAX,
     &ctx->fd0
   );
   T_eq_int( bytes_read, pos_in_file );
   T_eq_int( errno, EPROTO );
   T_no_more_interactions();
 }
 
 /*
  * Read a file from the server using only RFC1350.
  * The file is exactly one data packet long.
  * The client receives a malformed packet.
  * Tests:
  *   * The code supports requests without options (RFC1350 only).
  *   * The code supports the use of an IPv4 address instead of a server name.
  *   * The first packet is sent to standard port 69 of server.
  *   * All other packets are sent to the port used for this connection.
  *   * The first DATA packet received after the RRQ packet is malformed.
  *     It is too short with only three bytes length.
  *   * The client sends an error and terminates the file transfer upon
  *     reception of a malformed packet.
  */
 T_TEST_CASE_FIXTURE( read_file_malformed_ack_3, &fixture_rfc1350 )
 {
   tftp_test_context *ctx = T_fixture_context();
   int bytes_read;
   size_t pos_in_file = 0;
   static const uint8_t packet_too_short_3[] = { 0x00, 0x03, 0x00 };
 
   /* T_set_verbosity( T_VERBOSE ); */
   _Tftp_Add_interaction_socket( AF_INET, SOCK_DGRAM, 0, TFTP_FIRST_FD );
   _Tftp_Add_interaction_send_rrq(
     TFTP_FIRST_FD,
     tftpfs_file,
     TFTP_STD_PORT,
     tftpfs_ipv4_loopback,
     NO_BLOCK_SIZE_OPTION,
     NO_WINDOW_SIZE_OPTION,
     true
   );
   _Tftp_Add_interaction_recv_raw(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     sizeof( packet_too_short_3 ), /* Malformed DATA packet */
     packet_too_short_3,
     true
   );
   _Tftp_Add_interaction_send_error(
     TFTP_FIRST_FD,
     TFTP_ERROR_CODE_ILLEGAL,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     true
   );
   _Tftp_Add_interaction_close( TFTP_FIRST_FD, 0 );
 
   bytes_read = read_tftp_file(
     create_tftpfs_path( tftpfs_ipv4_loopback, tftpfs_file ),
     TFTP_RFC1350_BLOCK_SIZE / 4, /* Bytes read per call to read() */
     SIZE_MAX,
     &ctx->fd0
   );
   T_eq_int( bytes_read, pos_in_file );
   T_eq_int( errno, EPROTO );
   T_no_more_interactions();
 }
 
 /*
  * Read a file from the server using only RFC1350.
  * The file is exactly one data packet long.
  * The client receives a data packet with block number 0.
  * Tests:
  *   * The code supports requests without options (RFC1350 only).
  *   * The code supports the use of an IPv4 address instead of a server name.
  *   * The first packet is sent to standard port 69 of server.
  *   * All other packets are sent to the port used for this connection.
  *   * The first DATA packet received after the RRQ packet is malformed.
  *     It has block number 0.
  *   * The client sends an error and terminates the file transfer upon
  *     reception of a malformed packet.
  */
 T_TEST_CASE_FIXTURE( read_file_block_number_0, &fixture_rfc1350 )
 {
   tftp_test_context *ctx = T_fixture_context();
   int bytes_read;
   size_t pos_in_file = 0;
 
   /* T_set_verbosity( T_VERBOSE ); */
   _Tftp_Add_interaction_socket( AF_INET, SOCK_DGRAM, 0, TFTP_FIRST_FD );
   _Tftp_Add_interaction_send_rrq(
     TFTP_FIRST_FD,
     tftpfs_file,
     TFTP_STD_PORT,
     tftpfs_ipv4_loopback,
     NO_BLOCK_SIZE_OPTION,
     NO_WINDOW_SIZE_OPTION,
     true
   );
   _Tftp_Add_interaction_recv_data(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     0, /* Wrong block number 0 */
     pos_in_file,
     TFTP_RFC1350_BLOCK_SIZE, /* Number of bytes transferred */
     get_file_content,
     true
   );
   _Tftp_Add_interaction_send_error(
     TFTP_FIRST_FD,
     TFTP_ERROR_CODE_ILLEGAL,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     true
   );
   _Tftp_Add_interaction_close( TFTP_FIRST_FD, 0 );
 
   bytes_read = read_tftp_file(
     create_tftpfs_path( tftpfs_ipv4_loopback, tftpfs_file ),
     TFTP_RFC1350_BLOCK_SIZE / 4, /* Bytes read per call to read() */
     SIZE_MAX,
     &ctx->fd0
   );
   T_eq_int( bytes_read, pos_in_file );
   T_eq_int( errno, EPROTO );
   T_no_more_interactions();
 }
 
 /*
  * Read a file from the server using only RFC1350.
  * The file is exactly one data packet long.
  * The client receives a malformed packet.
  * Tests:
  *   * The code supports requests without options (RFC1350 only).
  *   * The code supports the use of an IPv4 address instead of a server name.
  *   * The first packet is sent to standard port 69 of server.
  *   * All other packets are sent to the port used for this connection.
  *   * The first DATA packet received after the RRQ packet is malformed.
  *     The packet contains an illegal op code.
  *   * The client sends an error and terminates the file transfer upon
  *     reception of a malformed packet.
  */
 T_TEST_CASE_FIXTURE( read_file_illegal_opcode_1, &fixture_rfc1350 )
 {
   tftp_test_context *ctx = T_fixture_context();
   int bytes_read;
   size_t pos_in_file = 0;
   static const uint8_t packet_illegal_opcode_1[] = { 0x00, 0xFF, 0x00, 0x00 };
 
   /* T_set_verbosity( T_VERBOSE ); */
   _Tftp_Add_interaction_socket( AF_INET, SOCK_DGRAM, 0, TFTP_FIRST_FD );
   _Tftp_Add_interaction_send_rrq(
     TFTP_FIRST_FD,
     tftpfs_file,
     TFTP_STD_PORT,
     tftpfs_ipv4_loopback,
     NO_BLOCK_SIZE_OPTION,
     NO_WINDOW_SIZE_OPTION,
     true
   );
   _Tftp_Add_interaction_recv_raw(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     sizeof( packet_illegal_opcode_1 ), /* Malformed DATA packet */
     packet_illegal_opcode_1,
     true
   );
   _Tftp_Add_interaction_send_error(
     TFTP_FIRST_FD,
     TFTP_ERROR_CODE_ILLEGAL,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     true
   );
   _Tftp_Add_interaction_close( TFTP_FIRST_FD, 0 );
 
   bytes_read = read_tftp_file(
     create_tftpfs_path( tftpfs_ipv4_loopback, tftpfs_file ),
     TFTP_RFC1350_BLOCK_SIZE / 4, /* Bytes read per call to read() */
     SIZE_MAX,
     &ctx->fd0
   );
   T_eq_int( bytes_read, pos_in_file );
   T_eq_int( errno, EPROTO );
   T_no_more_interactions();
 }
 
 /*
  * Read a file from the server using only RFC1350.
  * The file is exactly two data packet long.
  * The client receives DATA packets with wrong block numbers.
  * Tests:
  *   * The code supports requests without options (RFC1350 only).
  *   * The code supports the use of an IPv4 address instead of a server name.
  *   * The first packet is sent to standard port 69 of server.
  *   * The second RRQ is sent to the TFTP server port 69 and not to the
  *     port from which the first packet with the wrong block number came from.
  *   * The client uses a short time out for all packets.
  *   * The client uses a longer time out for repeated packets.
  *   * The client handles DATA packets with the wrong block numbers
  *     appropriately.
  *   * The third data packet is empty and signals the end of the transfer.
  *   * Old data packets are ignored (i.e. do not cause a retransmission).
  *   * Duplicates of the last data packet cause a retransmission of the
  *     last ACK.
  *   * The first data packet with a block number larger than the expected one,
  *     cause a retransmission of ACK or RRQ.  (They can appear together
  *     with the windowsize option.)
  *   * The test reads a file from the file system in one big chunk with is larger
  *     than the files size.
  */
 T_TEST_CASE_FIXTURE( read_two_block_file_wrong_block_numbers, &fixture_rfc1350 )
 {
   tftp_test_context *ctx = T_fixture_context();
   int bytes_read;
   uint16_t block_num = 1;
   size_t pos_in_file = 0;
 
   /* T_set_verbosity( T_VERBOSE ); */
   _Tftp_Add_interaction_socket( AF_INET, SOCK_DGRAM, 0, TFTP_FIRST_FD );
   _Tftp_Add_interaction_send_rrq(
     TFTP_FIRST_FD,
     tftpfs_file,
     TFTP_STD_PORT,
     tftpfs_ipv4_loopback,
     NO_BLOCK_SIZE_OPTION,
     NO_WINDOW_SIZE_OPTION,
     true
   );
   _Tftp_Add_interaction_recv_data(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     block_num + 1, /* Wrong block number */
     pos_in_file,
     TFTP_RFC1350_BLOCK_SIZE, /* Number of bytes transferred */
     get_file_content,
     true
   );
   _Tftp_Add_interaction_send_rrq(
     TFTP_FIRST_FD,
     tftpfs_file,
     TFTP_STD_PORT,
     tftpfs_ipv4_loopback,
     NO_BLOCK_SIZE_OPTION,
     NO_WINDOW_SIZE_OPTION,
     true
   );
   _Tftp_Add_interaction_recv_data(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     block_num + 1, /* Wrong block number */
     pos_in_file,
     TFTP_RFC1350_BLOCK_SIZE, /* Number of bytes transferred */
     get_file_content,
     true
   );
   _Tftp_Add_interaction_recv_data(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     block_num,
     pos_in_file,
     TFTP_RFC1350_BLOCK_SIZE, /* Number of bytes transferred */
     get_file_content,
     true
   );
   pos_in_file += TFTP_RFC1350_BLOCK_SIZE;
   _Tftp_Add_interaction_send_ack(
     TFTP_FIRST_FD,
     block_num++,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     true
   );
   _Tftp_Add_interaction_recv_data(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     block_num - 1, /*  Wrong block number / duplicates last packet */
     pos_in_file,
     TFTP_RFC1350_BLOCK_SIZE, /* Number of bytes transferred */
     get_file_content,
     true
   );
   _Tftp_Add_interaction_send_ack(
     TFTP_FIRST_FD,
     block_num - 1, /* Client assumes last ACK got lost and retransmits it. */
     SERV_PORT,
     tftpfs_ipv4_loopback,
     true
   );
   _Tftp_Add_interaction_recv_data(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     block_num + 1, /*  Wrong block number */
     pos_in_file,
     TFTP_RFC1350_BLOCK_SIZE, /* Number of bytes transferred */
     get_file_content,
     true
   );
   _Tftp_Add_interaction_send_ack(
     TFTP_FIRST_FD,
     block_num - 1, /* Client assumes last ACK got lost and retransmits it. */
     SERV_PORT,
     tftpfs_ipv4_loopback,
     true
   );
   _Tftp_Add_interaction_recv_data(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     block_num + 1, /*  Wrong block number */
     pos_in_file,
     TFTP_RFC1350_BLOCK_SIZE, /* Number of bytes transferred */
     get_file_content,
     true
   );
   _Tftp_Add_interaction_recv_data(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     block_num,
     pos_in_file,
     TFTP_RFC1350_BLOCK_SIZE, /* Number of bytes transferred */
     get_file_content,
     true
   );
   pos_in_file += TFTP_RFC1350_BLOCK_SIZE;
   _Tftp_Add_interaction_send_ack(
     TFTP_FIRST_FD,
     block_num++,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     true
   );
   _Tftp_Add_interaction_recv_data(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     block_num - 2, /*  Wrong block number */
     pos_in_file,
     TFTP_RFC1350_BLOCK_SIZE, /* Number of bytes transferred */
     get_file_content,
     true
   );
   _Tftp_Add_interaction_recv_data(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     block_num + 1, /*  Wrong block number */
     pos_in_file,
     TFTP_RFC1350_BLOCK_SIZE, /* Number of bytes transferred */
     get_file_content,
     true
   );
   _Tftp_Add_interaction_send_ack(
     TFTP_FIRST_FD,
     block_num - 1, /* Client assumes last ACK got lost and retransmits it. */
     SERV_PORT,
     tftpfs_ipv4_loopback,
     true
   );
   _Tftp_Add_interaction_recv_data(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     block_num,
     pos_in_file,
     0, /* Number of bytes transferred */
     get_file_content,
     true
   );
   _Tftp_Add_interaction_send_ack(
     TFTP_FIRST_FD,
     block_num++,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     true
   );
   _Tftp_Add_interaction_close( TFTP_FIRST_FD, 0 );
 
   bytes_read = read_tftp_file(
     create_tftpfs_path( tftpfs_ipv4_loopback, tftpfs_file ),
     /* Bytes read per call to read() */
     3 * TFTP_RFC1350_BLOCK_SIZE,
     SIZE_MAX,
     &ctx->fd0
   );
   T_eq_int( bytes_read, pos_in_file );
   T_no_more_interactions();
 }
 
 /*
  * Attempt to read a file from the server using filename without ':'.
  * Tests:
  *   * The TFTP FS rejects malformed file names (i.e. it does not crash).
  */
 T_TEST_CASE_FIXTURE( read_malformed_filename, &fixture_rfc1350 )
 {
   tftp_test_context *ctx = T_fixture_context();
   int bytes_read;
   char buffer[100];
   int len;
 
   len = snprintf(
     buffer,
     sizeof( buffer ),
     "%s/%s",
     tftpfs_mount_point,
     tftpfs_server0_name
   );
 
   T_quiet_gt_int( len, 0 );
   T_quiet_lt_int( len, (int) sizeof( buffer ) );
 
   bytes_read = read_tftp_file(
     buffer,
     /* Bytes read per call to read() */
     TFTP_RFC1350_BLOCK_SIZE,
     SIZE_MAX,
     &ctx->fd0
   );
   T_assert_eq_int( bytes_read, 0 );
   T_assert_eq_int( errno, EINVAL );
 }
 
 /*
  * Attempt to read a file from a none exiting server address.
  * Tests:
  *   * TFTP FS returns an error if the server name cannot be resolved.
  */
 T_TEST_CASE_FIXTURE( read_from_unknown_ip_address, &fixture_rfc1350 )
 {
   tftp_test_context *ctx = T_fixture_context();
   int bytes_read;
 
   bytes_read = read_tftp_file(
     create_tftpfs_path( "not-existing-server-address", tftpfs_file ),
     /* Bytes read per call to read() */
     TFTP_RFC1350_BLOCK_SIZE,
     SIZE_MAX,
     &ctx->fd0
   );
   T_assert_eq_int( bytes_read, 0 );
   T_assert_eq_int( errno, ENOENT );
 }
 
 /*
  * Attempt to read a file which the server does not know
  * No timeouts, packet loss, ...
  * Tests:
  *   * The code supports requests without options (RFC1350 only).
  *   * The code supports the use of a server name instead of an IP address.
  *   * The client handles an ERROR packet received upon sending an RRQ
  *     correctly.
  *   * TFTP FS returns an error upon the reception of the ERROR packet.
  */
 T_TEST_CASE_FIXTURE( read_not_existing_file, &fixture_rfc1350 )
 {
   tftp_test_context *ctx = T_fixture_context();
   int bytes_read;
 
   /* T_set_verbosity( T_VERBOSE ); */
   _Tftp_Add_interaction_socket( AF_INET, SOCK_DGRAM, 0, TFTP_FIRST_FD );
   _Tftp_Add_interaction_send_rrq(
     TFTP_FIRST_FD,
     tftpfs_file,
     TFTP_STD_PORT,
     tftpfs_server0_ipv4,
     NO_BLOCK_SIZE_OPTION,
     NO_WINDOW_SIZE_OPTION,
     true
   );
   _Tftp_Add_interaction_recv_error(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_server0_ipv4,
     TFTP_ERROR_CODE_NOT_FOUND,
     "No such file",
     true
   );
   _Tftp_Add_interaction_close( TFTP_FIRST_FD, 0 );
 
   bytes_read = read_tftp_file(
     create_tftpfs_path( tftpfs_server0_name, tftpfs_file ),
     /* Bytes read per call to read() */
     TFTP_RFC1350_BLOCK_SIZE,
     SIZE_MAX,
     &ctx->fd0
   );
   T_assert_eq_int( bytes_read, 0 );
   T_assert_eq_int( errno, ENOENT );
   T_no_more_interactions();
 }
 
 /*
  * Write an empty file to the server using only RFC1350.
  * The first two WRQ as well as the first two DATA packets are lost.
  * Tests:
  *   * The code supports requests without options (RFC1350 only).
  *   * The code supports the use of a server name instead of an IP address.
  *   * The all WRQ are sent to standard port 69 of server.
  *   * All other packets are sent to the port used for this connection.
  *   * The client uses a short time out for first packets.
  *   * The client uses a longer time out for repeated packets.
  *   * The client repeats the WRQs and DATA packets which are supposed
  *     to be lost.
  *   * When a timeout occurs, the client repeats the last and empty packet.
  *   * The first data packet is empty and signals the end of the transfer.
  *   * The test writes a file with 0 bytes content to the file system.
  */
 T_TEST_CASE_FIXTURE( write_empty_file_packet_losts, &fixture_rfc1350 )
 {
   tftp_test_context *ctx = T_fixture_context();
   int bytes_written;
   uint16_t block_num = 0;
   size_t pos_in_file = 0;
 
   /* T_set_verbosity( T_VERBOSE ); */
   _Tftp_Add_interaction_socket( AF_INET, SOCK_DGRAM, 0, TFTP_FIRST_FD );
   _Tftp_Add_interaction_send_wrq(
     TFTP_FIRST_FD,
     tftpfs_file,
     TFTP_STD_PORT,
     tftpfs_server0_ipv4,
     NO_BLOCK_SIZE_OPTION,
     NO_WINDOW_SIZE_OPTION,
     true
   );
   _Tftp_Add_interaction_recv_nothing(
     TFTP_FIRST_FD, /* Timeout: No packet received within timeout period */
     FIRST_TIMEOUT_MILLISECONDS
   );
   _Tftp_Add_interaction_send_wrq(
     TFTP_FIRST_FD,
     tftpfs_file,
     TFTP_STD_PORT,
     tftpfs_server0_ipv4,
     NO_BLOCK_SIZE_OPTION,
     NO_WINDOW_SIZE_OPTION,
     true
   );
   _Tftp_Add_interaction_recv_nothing(
     TFTP_FIRST_FD, /* Timeout: No packet received within timeout period */
     TIMEOUT_MILLISECONDS
   );
   _Tftp_Add_interaction_send_wrq(
     TFTP_FIRST_FD,
     tftpfs_file,
     TFTP_STD_PORT,
     tftpfs_server0_ipv4,
     NO_BLOCK_SIZE_OPTION,
     NO_WINDOW_SIZE_OPTION,
     true
   );
   _Tftp_Add_interaction_recv_ack(
     TFTP_FIRST_FD,
     TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_server0_ipv4,
     block_num++,
     true
   );
   _Tftp_Add_interaction_send_data(
     TFTP_FIRST_FD,
     block_num,
     pos_in_file,
     0, /* Number of bytes transferred */
     get_file_content,
     SERV_PORT,
     tftpfs_server0_ipv4,
     true
   );
   _Tftp_Add_interaction_recv_nothing(
     TFTP_FIRST_FD, /* Timeout: No packet received within timeout period */
     FIRST_TIMEOUT_MILLISECONDS
   );
   _Tftp_Add_interaction_send_data(
     TFTP_FIRST_FD,
     block_num,
     pos_in_file,
     0, /* Number of bytes transferred */
     get_file_content,
     SERV_PORT,
     tftpfs_server0_ipv4,
     true
   );
   _Tftp_Add_interaction_recv_nothing(
     TFTP_FIRST_FD, /* Timeout: No packet received within timeout period */
     TIMEOUT_MILLISECONDS
   );
   _Tftp_Add_interaction_send_data(
     TFTP_FIRST_FD,
     block_num,
     pos_in_file,
     0, /* Number of bytes transferred */
     get_file_content,
     SERV_PORT,
     tftpfs_server0_ipv4,
     true
   );
   _Tftp_Add_interaction_recv_ack(
     TFTP_FIRST_FD,
     TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_server0_ipv4,
     block_num++,
     true
   );
   _Tftp_Add_interaction_close( TFTP_FIRST_FD, 0 );
 
   bytes_written = write_tftp_file(
     create_tftpfs_path( tftpfs_server0_name, tftpfs_file ),
     0, /* Size of file */
     4, /* Bytes written per call to write() */
     &ctx->fd0
   );
   T_eq_int( bytes_written, pos_in_file );
   T_no_more_interactions();
 }
 
 /*
  * Write a very short file to the server using only RFC1350.
  * The file is one and half data packets long.
  * The first two DATA packets and one ACK packet are lost.
  * Tests:
  *   * The code supports requests without options (RFC1350 only).
  *   * The code supports the use of a server name instead of an IP address.
  *   * The first packet is sent to standard port 69 of server.
  *   * All other packets are sent to the port used for this connection.
  *   * The client uses a short time out for first packets.
  *   * The client uses a longer time out for repeated packets.
  *   * The client repeats sending DATA packets which are supposed
  *     to be lost.
  *   * The client also repeats the last DATA packet when it is supposed
  *     to be lost.
  *   * The client repeats sending DATA packets when an ACK packet is repeated
  *     (presumably the DATA packet has been lost).
  *   * The test writes a file to the file system in chunks of a quarter of the block size.
  */
 T_TEST_CASE_FIXTURE( write_tiny_file_packet_losts, &fixture_rfc1350 )
 {
   tftp_test_context *ctx = T_fixture_context();
   int bytes_written;
   uint16_t block_num = 0;
   size_t pos_in_file = 0;
 
   /* T_set_verbosity( T_VERBOSE ); */
   _Tftp_Add_interaction_socket( AF_INET, SOCK_DGRAM, 0, TFTP_FIRST_FD );
   _Tftp_Add_interaction_send_wrq(
     TFTP_FIRST_FD,
     tftpfs_file,
     TFTP_STD_PORT,
     tftpfs_server0_ipv4,
     NO_BLOCK_SIZE_OPTION,
     NO_WINDOW_SIZE_OPTION,
     true
   );
   _Tftp_Add_interaction_recv_ack(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_server0_ipv4,
     block_num++,
     true
   );
   _Tftp_Add_interaction_send_data(
     TFTP_FIRST_FD,
     block_num,
     pos_in_file,
     TFTP_RFC1350_BLOCK_SIZE,
     get_file_content,
     SERV_PORT,
     tftpfs_server0_ipv4,
     true
   );
   _Tftp_Add_interaction_recv_nothing(
     TFTP_FIRST_FD, /* Timeout: No packet received within timeout period */
     FIRST_TIMEOUT_MILLISECONDS
   );
   _Tftp_Add_interaction_send_data(
     TFTP_FIRST_FD,
     block_num,
     pos_in_file,
     TFTP_RFC1350_BLOCK_SIZE,
     get_file_content,
     SERV_PORT,
     tftpfs_server0_ipv4,
     true
   );
   _Tftp_Add_interaction_recv_nothing(
     TFTP_FIRST_FD, /* Timeout: No packet received within timeout period */
     TIMEOUT_MILLISECONDS
   );
   _Tftp_Add_interaction_send_data(
     TFTP_FIRST_FD,
     block_num,
     pos_in_file,
     TFTP_RFC1350_BLOCK_SIZE,
     get_file_content,
     SERV_PORT,
     tftpfs_server0_ipv4,
     true
   );
   _Tftp_Add_interaction_recv_ack(
     TFTP_FIRST_FD,
     TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_server0_ipv4,
     block_num++,
     true
   );
   pos_in_file += TFTP_RFC1350_BLOCK_SIZE;
   _Tftp_Add_interaction_send_data(
     TFTP_FIRST_FD,
     block_num,
     pos_in_file,
     TFTP_RFC1350_BLOCK_SIZE / 2,
     get_file_content,
     SERV_PORT,
     tftpfs_server0_ipv4,
     true
   );
   _Tftp_Add_interaction_recv_ack(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_server0_ipv4,
     block_num - 1, /* Repeated ACK packet received */
     true
   );
   _Tftp_Add_interaction_send_data(
     TFTP_FIRST_FD,
     block_num,
     pos_in_file,
     TFTP_RFC1350_BLOCK_SIZE / 2,
     get_file_content,
     SERV_PORT,
     tftpfs_server0_ipv4,
     true
   );
   pos_in_file += TFTP_RFC1350_BLOCK_SIZE / 2;
   _Tftp_Add_interaction_recv_ack(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_server0_ipv4,
     block_num++,
     true
   );
   _Tftp_Add_interaction_close( TFTP_FIRST_FD, 0 );
 
   bytes_written = write_tftp_file(
     create_tftpfs_path( tftpfs_server0_name, tftpfs_file ),
     TFTP_RFC1350_BLOCK_SIZE / 2 * 3, /* Size of file */
     TFTP_RFC1350_BLOCK_SIZE / 4, /* Bytes written per call to write() */
     &ctx->fd0
   );
   T_eq_int( bytes_written, pos_in_file );
   T_no_more_interactions();
 }
 
 /*
  * Write a file to the server using only RFC1350.
  * The file is 2 data packet and 1 byte long.  No timeouts, packet loss, ...
  * Tests:
  *   * The code supports requests without options (RFC1350 only).
  *   * The code supports the use of an IPv4 address instead of a server name.
  *   * The first packet is sent to standard port 69 of server.
  *   * All other packets are sent to the port used for this connection.
  *   * First and second data packet is full.
  *   * Third data packet signals the end of transfer.
  *   * The test writes a file to the file system in one big chunk
  *     of exactly the files size.
  */
 T_TEST_CASE_FIXTURE( write_simple_file, &fixture_rfc1350 )
 {
   tftp_test_context *ctx = T_fixture_context();
   int bytes_written;
   uint16_t block_num = 0;
   size_t pos_in_file = 0;
 
   /* T_set_verbosity( T_VERBOSE ); */
   _Tftp_Add_interaction_socket( AF_INET, SOCK_DGRAM, 0, TFTP_FIRST_FD );
   _Tftp_Add_interaction_send_wrq(
     TFTP_FIRST_FD,
     tftpfs_file,
     TFTP_STD_PORT,
     tftpfs_ipv4_loopback,
     NO_BLOCK_SIZE_OPTION,
     NO_WINDOW_SIZE_OPTION,
     true
   );
   _Tftp_Add_interaction_recv_ack(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     block_num++,
     true
   );
   _Tftp_Add_interaction_send_data(
     TFTP_FIRST_FD,
     block_num,
     pos_in_file,
     TFTP_RFC1350_BLOCK_SIZE,
     get_file_content,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     true
   );
   pos_in_file += TFTP_RFC1350_BLOCK_SIZE;
   _Tftp_Add_interaction_recv_ack(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     block_num++,
     true
   );
   _Tftp_Add_interaction_send_data(
     TFTP_FIRST_FD,
     block_num,
     pos_in_file,
     TFTP_RFC1350_BLOCK_SIZE,
     get_file_content,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     true
   );
   pos_in_file += TFTP_RFC1350_BLOCK_SIZE;
   _Tftp_Add_interaction_recv_ack(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     block_num++,
     true
   );
   _Tftp_Add_interaction_send_data(
     TFTP_FIRST_FD,
     block_num,
     pos_in_file,
     1, /* Data bytes in this block */
     get_file_content,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     true
   );
   pos_in_file += 1;
   _Tftp_Add_interaction_recv_ack(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     block_num++,
     true
   );
   _Tftp_Add_interaction_close( TFTP_FIRST_FD, 0 );
 
   bytes_written = write_tftp_file(
     create_tftpfs_path( tftpfs_ipv4_loopback, tftpfs_file ),
     pos_in_file, /* Size of file */
     pos_in_file, /* Bytes written per call to write() */
     &ctx->fd0
   );
   T_eq_int( bytes_written, pos_in_file );
   T_no_more_interactions();
 }
 
 /*
  * Write a file to the server using only RFC1350.
  * As response to the first DATA packet, the server sends an error packet.
  * Tests:
  *   * The code supports requests without options (RFC1350 only).
  *   * The code supports the use of an IPv4 address instead of a server name.
  *   * The first packet is sent to standard port 69 of server.
  *   * All other packets are sent to the port used for this connection.
  *   * The first data packet is full.
  *   * The second packet from the server is an error packet.
  *   * The TFTP client ends the connection after receiving an error packet.
  *   * The test writes a file to the file system with a call to write()
  *     for each byte.
  */
 T_TEST_CASE_FIXTURE( write_simple_file_disk_full, &fixture_rfc1350 )
 {
   tftp_test_context *ctx = T_fixture_context();
   int bytes_written;
   uint16_t block_num = 0;
   size_t pos_in_file = 0;
 
   /* T_set_verbosity( T_VERBOSE ); */
   _Tftp_Add_interaction_socket( AF_INET, SOCK_DGRAM, 0, TFTP_FIRST_FD );
   _Tftp_Add_interaction_send_wrq(
     TFTP_FIRST_FD,
     tftpfs_file,
     TFTP_STD_PORT,
     tftpfs_ipv4_loopback,
     NO_BLOCK_SIZE_OPTION,
     NO_WINDOW_SIZE_OPTION,
     true
   );
   _Tftp_Add_interaction_recv_ack(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     block_num++,
     true
   );
   _Tftp_Add_interaction_send_data(
     TFTP_FIRST_FD,
     block_num,
     pos_in_file,
     TFTP_RFC1350_BLOCK_SIZE,
     get_file_content,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     true
   );
   pos_in_file += TFTP_RFC1350_BLOCK_SIZE;
   _Tftp_Add_interaction_recv_error(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     TFTP_ERROR_CODE_DISK_FULL,
     "disk full",
     true
   );
   _Tftp_Add_interaction_close( TFTP_FIRST_FD, 0 );
 
   bytes_written = write_tftp_file(
     create_tftpfs_path( tftpfs_ipv4_loopback, tftpfs_file ),
     pos_in_file, /* Size of file */
     1, /* Bytes written per call to write() */
     &ctx->fd0
   );
   T_eq_int( errno, ENOSPC );
   T_eq_int( bytes_written, pos_in_file - 1 );
   T_no_more_interactions();
 }
 
 /*
  * Write a file to the server using only RFC1350.
  * The file is one and a half data packet long.
  * The server sends a malformed packet.
  * Tests:
  *   * The code supports requests without options (RFC1350 only).
  *   * The code supports the use of an IPv4 address instead of a server name.
  *   * The first packet is sent to standard port 69 of server.
  *   * All other packets are sent to the port used for this connection.
  *   * The first ACK to the WRQ packet is malformed.
  *     It is only one byte long.
  *   * The client sends an error upon the reception of a malformed packet
  *     and terminates the file transfer.
  */
 T_TEST_CASE_FIXTURE( write_file_malformed_ack_1, &fixture_rfc1350 )
 {
   tftp_test_context *ctx = T_fixture_context();
   int bytes_written;
   size_t pos_in_file = 0;
   static const uint8_t packet_too_short_1[] = { 0x04 };
 
   /* T_set_verbosity( T_VERBOSE ); */
   _Tftp_Add_interaction_socket( AF_INET, SOCK_DGRAM, 0, TFTP_FIRST_FD );
   _Tftp_Add_interaction_send_wrq(
     TFTP_FIRST_FD,
     tftpfs_file,
     TFTP_STD_PORT,
     tftpfs_ipv4_loopback,
     NO_BLOCK_SIZE_OPTION,
     NO_WINDOW_SIZE_OPTION,
     true
   );
   _Tftp_Add_interaction_recv_raw(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     sizeof( packet_too_short_1 ), /* Malformed ACK packet */
     packet_too_short_1,
     true
   );
   _Tftp_Add_interaction_send_error(
     TFTP_FIRST_FD,
     TFTP_ERROR_CODE_ILLEGAL,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     true
   );
   _Tftp_Add_interaction_close( TFTP_FIRST_FD, 0 );
 
   bytes_written = write_tftp_file(
     create_tftpfs_path( tftpfs_ipv4_loopback, tftpfs_file ),
     pos_in_file, /* Size of file */
     17, /* Bytes written per call to write() */
     &ctx->fd0
   );
   T_eq_int( bytes_written, -1 );
   T_eq_int( errno, EPROTO );
   T_no_more_interactions();
 }
 
 /*
  * Write a file to the server using only RFC1350.
  * The file is one and a half data packet long.
  * The server sends a malformed packet.
  * Tests:
  *   * The code supports requests without options (RFC1350 only).
  *   * The code supports the use of an IPv4 address instead of a server name.
  *   * The first packet is sent to standard port 69 of server.
  *   * All other packets are sent to the port used for this connection.
  *   * The first ACK to the WRQ packet is malformed.
  *     It is only two bytes long.
  *   * The client sends an error upon the reception of a malformed packet
  *     and terminates the file transfer.
  */
 T_TEST_CASE_FIXTURE( write_file_malformed_ack_2, &fixture_rfc1350 )
 {
   tftp_test_context *ctx = T_fixture_context();
   int bytes_written;
   size_t pos_in_file = 0;
   static const uint8_t packet_too_short_2[] = { 0x00, 0x04 };
 
   /* T_set_verbosity( T_VERBOSE ); */
   _Tftp_Add_interaction_socket( AF_INET, SOCK_DGRAM, 0, TFTP_FIRST_FD );
   _Tftp_Add_interaction_send_wrq(
     TFTP_FIRST_FD,
     tftpfs_file,
     TFTP_STD_PORT,
     tftpfs_ipv4_loopback,
     NO_BLOCK_SIZE_OPTION,
     NO_WINDOW_SIZE_OPTION,
     true
   );
   _Tftp_Add_interaction_recv_raw(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     sizeof( packet_too_short_2 ), /* Malformed ACK packet */
     packet_too_short_2,
     true
   );
   _Tftp_Add_interaction_send_error(
     TFTP_FIRST_FD,
     TFTP_ERROR_CODE_ILLEGAL,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     true
   );
   _Tftp_Add_interaction_close( TFTP_FIRST_FD, 0 );
 
   bytes_written = write_tftp_file(
     create_tftpfs_path( tftpfs_ipv4_loopback, tftpfs_file ),
     pos_in_file, /* Size of file */
     17, /* Bytes written per call to write() */
     &ctx->fd0
   );
   T_eq_int( bytes_written, -1 );
   T_eq_int( errno, EPROTO );
   T_no_more_interactions();
 }
 
 /*
  * Write a file to the server using only RFC1350.
  * The file is one and a half data packet long.
  * The server sends a malformed packet.
  * Tests:
  *   * The code supports requests without options (RFC1350 only).
  *   * The code supports the use of an IPv4 address instead of a server name.
  *   * The first packet is sent to standard port 69 of server.
  *   * All other packets are sent to the port used for this connection.
  *   * The first ACK to the WRQ packet is malformed.
  *     It is only three bytes long.
  *   * The client sends an error upon the reception of a malformed packet
  *     and terminates the file transfer.
  */
 T_TEST_CASE_FIXTURE( write_file_malformed_ack_3, &fixture_rfc1350 )
 {
   tftp_test_context *ctx = T_fixture_context();
   int bytes_written;
   size_t pos_in_file = 0;
   static const uint8_t packet_too_short_3[] = { 0x00, 0x04, 0x00 };
 
   /* T_set_verbosity( T_VERBOSE ); */
   _Tftp_Add_interaction_socket( AF_INET, SOCK_DGRAM, 0, TFTP_FIRST_FD );
   _Tftp_Add_interaction_send_wrq(
     TFTP_FIRST_FD,
     tftpfs_file,
     TFTP_STD_PORT,
     tftpfs_ipv4_loopback,
     NO_BLOCK_SIZE_OPTION,
     NO_WINDOW_SIZE_OPTION,
     true
   );
   _Tftp_Add_interaction_recv_raw(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     sizeof( packet_too_short_3 ), /* Malformed ACK packet */
     packet_too_short_3,
     true
   );
   _Tftp_Add_interaction_send_error(
     TFTP_FIRST_FD,
     TFTP_ERROR_CODE_ILLEGAL,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     true
   );
   _Tftp_Add_interaction_close( TFTP_FIRST_FD, 0 );
 
   bytes_written = write_tftp_file(
     create_tftpfs_path( tftpfs_ipv4_loopback, tftpfs_file ),
     pos_in_file, /* Size of file */
     17, /* Bytes written per call to write() */
     &ctx->fd0
   );
   T_eq_int( bytes_written, -1 );
   T_eq_int( errno, EPROTO );
   T_no_more_interactions();
 }
 
 /*
  * Write a file to the server using only RFC1350.
  * The file is one and a half data packet long.
  * The server sends a malformed packet.
  * Tests:
  *   * The code supports requests without options (RFC1350 only).
  *   * The code supports the use of an IPv4 address instead of a server name.
  *   * The first packet is sent to standard port 69 of server.
  *   * All other packets are sent to the port used for this connection.
  *   * The first ACK to the WRQ packet is malformed.
  *     The packet contains an illegal op code.
  *   * The client sends an error upon the reception of a malformed packet
  *     and terminates the file transfer.
  */
 T_TEST_CASE_FIXTURE( write_file_illegal_opcode_1, &fixture_rfc1350 )
 {
   tftp_test_context *ctx = T_fixture_context();
   int bytes_written;
   size_t pos_in_file = 0;
   static const uint8_t packet_illegal_opcode_1[] = { 0x00, 0xFF, 0x00, 0x00 };
 
   /* T_set_verbosity( T_VERBOSE ); */
   _Tftp_Add_interaction_socket( AF_INET, SOCK_DGRAM, 0, TFTP_FIRST_FD );
   _Tftp_Add_interaction_send_wrq(
     TFTP_FIRST_FD,
     tftpfs_file,
     TFTP_STD_PORT,
     tftpfs_ipv4_loopback,
     NO_BLOCK_SIZE_OPTION,
     NO_WINDOW_SIZE_OPTION,
     true
   );
   _Tftp_Add_interaction_recv_raw(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     sizeof( packet_illegal_opcode_1 ), /* Malformed ACK packet */
     packet_illegal_opcode_1,
     true
   );
   _Tftp_Add_interaction_send_error(
     TFTP_FIRST_FD,
     TFTP_ERROR_CODE_ILLEGAL,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     true
   );
   _Tftp_Add_interaction_close( TFTP_FIRST_FD, 0 );
 
   bytes_written = write_tftp_file(
     create_tftpfs_path( tftpfs_ipv4_loopback, tftpfs_file ),
     pos_in_file, /* Size of file */
     17, /* Bytes written per call to write() */
     &ctx->fd0
   );
   T_eq_int( bytes_written, -1 );
   T_eq_int( errno, EPROTO );
   T_no_more_interactions();
 }
 
 /*
  * Write a file to the server using only RFC1350.
  * The server sends a malformed packet.
  * Tests:
  *   * The code supports requests without options (RFC1350 only).
  *   * The code supports the use of an IPv4 address instead of a server name.
  *   * The first packet is sent to standard port 69 of server.
  *   * All other packets are sent to the port used for this connection.
  *   * A malformed ACK packet is received by the TFTP client.
  *     The packet is only three bytes long.
  *   * The client sends an error upon the reception of a malformed packet
  *     and terminates the file transfer.
  */
 T_TEST_CASE_FIXTURE( write_short_file_malformed_ACK_1, &fixture_rfc1350 )
 {
   tftp_test_context *ctx = T_fixture_context();
   int bytes_written;
   uint16_t block_num = 0;
   size_t pos_in_file = 0;
   static const uint8_t packet_too_short_3[] = { 0x00, 0x04, 0x00 };
 
   /* T_set_verbosity( T_VERBOSE ); */
   _Tftp_Add_interaction_socket( AF_INET, SOCK_DGRAM, 0, TFTP_FIRST_FD );
   _Tftp_Add_interaction_send_wrq(
     TFTP_FIRST_FD,
     tftpfs_file,
     TFTP_STD_PORT,
     tftpfs_ipv4_loopback,
     NO_BLOCK_SIZE_OPTION,
     NO_WINDOW_SIZE_OPTION,
     true
   );
   _Tftp_Add_interaction_recv_ack(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     block_num++,
     true
   );
   _Tftp_Add_interaction_send_data(
     TFTP_FIRST_FD,
     block_num,
     pos_in_file,
     TFTP_RFC1350_BLOCK_SIZE,
     get_file_content,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     true
   );
   _Tftp_Add_interaction_recv_raw(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     sizeof( packet_too_short_3 ), /* Malformed ACK packet */
     packet_too_short_3,
     true
   );
   _Tftp_Add_interaction_send_error(
     TFTP_FIRST_FD,
     TFTP_ERROR_CODE_ILLEGAL,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     true
   );
   _Tftp_Add_interaction_close( TFTP_FIRST_FD, 0 );
 
   bytes_written = write_tftp_file(
     create_tftpfs_path( tftpfs_ipv4_loopback, tftpfs_file ),
     2 * TFTP_RFC1350_BLOCK_SIZE, /* Size of file */
     17, /* Bytes written per call to write() */
     &ctx->fd0
   );
   T_eq_int( errno, EPROTO );
   T_eq_int( bytes_written, 510 );
   T_no_more_interactions();
 }
 
 /*
  * Write a file to the server using only RFC1350.
  * The server sends a malformed packet.
  * Tests:
  *   * The code supports requests without options (RFC1350 only).
  *   * The code supports the use of an IPv4 address instead of a server name.
  *   * The first packet is sent to standard port 69 of server.
  *   * All other packets are sent to the port used for this connection.
  *   * A malformed ACK packet is received by the TFTP client after the first
  *     DATA packet has been exchanged successfully.
  *     The packet is only one byte long.
  *   * The client sends an error upon the reception of a malformed packet
  *     and terminates the file transfer.
  */
 T_TEST_CASE_FIXTURE( write_short_file_malformed_ACK_2, &fixture_rfc1350 )
 {
   tftp_test_context *ctx = T_fixture_context();
   int bytes_written;
   uint16_t block_num = 0;
   size_t pos_in_file = 0;
   static const uint8_t packet_too_short_1[] = { 0x04 };
 
   /* T_set_verbosity( T_VERBOSE ); */
   _Tftp_Add_interaction_socket( AF_INET, SOCK_DGRAM, 0, TFTP_FIRST_FD );
   _Tftp_Add_interaction_send_wrq(
     TFTP_FIRST_FD,
     tftpfs_file,
     TFTP_STD_PORT,
     tftpfs_ipv4_loopback,
     NO_BLOCK_SIZE_OPTION,
     NO_WINDOW_SIZE_OPTION,
     true
   );
   _Tftp_Add_interaction_recv_ack(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     block_num++,
     true
   );
   _Tftp_Add_interaction_send_data(
     TFTP_FIRST_FD,
     block_num,
     pos_in_file,
     TFTP_RFC1350_BLOCK_SIZE,
     get_file_content,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     true
   );
   pos_in_file += TFTP_RFC1350_BLOCK_SIZE;
   _Tftp_Add_interaction_recv_ack(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     block_num++,
     true
   );
   _Tftp_Add_interaction_send_data(
     TFTP_FIRST_FD,
     block_num,
     pos_in_file,
     TFTP_RFC1350_BLOCK_SIZE / 4,
     get_file_content,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     true
   );
   pos_in_file += TFTP_RFC1350_BLOCK_SIZE / 4;
   _Tftp_Add_interaction_recv_raw(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     sizeof( packet_too_short_1 ), /* Malformed ACK packet */
     packet_too_short_1,
     true
   );
   _Tftp_Add_interaction_send_error(
     TFTP_FIRST_FD,
     TFTP_ERROR_CODE_ILLEGAL,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     true
   );
   _Tftp_Add_interaction_close( TFTP_FIRST_FD, 0 );
 
   bytes_written = write_tftp_file(
     create_tftpfs_path( tftpfs_ipv4_loopback, tftpfs_file ),
     pos_in_file, /* Size of file */
     17, /* Bytes written per call to write() */
     &ctx->fd0
   );
   T_eq_int( errno, EPROTO );
   T_eq_int( bytes_written, -1 );
   T_no_more_interactions();
 }
 
 /*
  * Write a file to the server using only RFC1350.
  * The server sends a malformed packet.
  * Tests:
  *   * The code supports requests without options (RFC1350 only).
  *   * The code supports the use of an IPv4 address instead of a server name.
  *   * The first packet is sent to standard port 69 of server.
  *   * All other packets are sent to the port used for this connection.
  *   * A malformed ACK packet is received by the TFTP client after the first
  *     DATA packet has been exchanged successfully.
  *     The packet contains an illegal op code.
  *   * The client sends an error upon the reception of a malformed packet
  *     and terminates the file transfer.
  */
 T_TEST_CASE_FIXTURE( write_short_file_malformed_opcode, &fixture_rfc1350 )
 {
   tftp_test_context *ctx = T_fixture_context();
   int bytes_written;
   uint16_t block_num = 0;
   size_t pos_in_file = 0;
   static const uint8_t packet_illegal_opcode_2[] = { 0x04, 0x00, 0x00, 0x01 };
 
   /* T_set_verbosity( T_VERBOSE ); */
   _Tftp_Add_interaction_socket( AF_INET, SOCK_DGRAM, 0, TFTP_FIRST_FD );
   _Tftp_Add_interaction_send_wrq(
     TFTP_FIRST_FD,
     tftpfs_file,
     TFTP_STD_PORT,
     tftpfs_ipv4_loopback,
     NO_BLOCK_SIZE_OPTION,
     NO_WINDOW_SIZE_OPTION,
     true
   );
   _Tftp_Add_interaction_recv_ack(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     block_num++,
     true
   );
   _Tftp_Add_interaction_send_data(
     TFTP_FIRST_FD,
     block_num,
     pos_in_file,
     TFTP_RFC1350_BLOCK_SIZE,
     get_file_content,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     true
   );
   _Tftp_Add_interaction_recv_raw(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     sizeof( packet_illegal_opcode_2 ), /* Malformed ACK packet */
     packet_illegal_opcode_2,
     true
   );
   _Tftp_Add_interaction_send_error(
     TFTP_FIRST_FD,
     TFTP_ERROR_CODE_ILLEGAL,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     true
   );
   _Tftp_Add_interaction_close( TFTP_FIRST_FD, 0 );
 
   bytes_written = write_tftp_file(
     create_tftpfs_path( tftpfs_ipv4_loopback, tftpfs_file ),
     2 * TFTP_RFC1350_BLOCK_SIZE, /* Size of file */
     17, /* Bytes written per call to write() */
     &ctx->fd0
   );
   T_eq_int( errno, EPROTO );
   T_eq_int( bytes_written, 510 );
   T_no_more_interactions();
 }
 
 /*
  * Write a file to the server using only RFC1350.
  * The file is two and a half data packet long.
  * The server sends packets with wrong block numbers.
  * Tests:
  *   * The code supports requests without options (RFC1350 only).
  *   * The code supports the use of an IPv4 address instead of a server name.
  *   * The first packet is sent to standard port 69 of server.
  *   * All other packets are sent to the port used for this connection.
  *   * The first ACK packet contains a wrong block number.
  *   * The client repeats the WRQ upon reception of an ACK with
  *     an too high block number.
  *   * The client uses a short time out for waiting on the answer of the
  *     first WRQ or DATA packets.
  *   * The client uses a long time out for waiting on the answer of
  *     repeated WRQ or DATA packets.
  *   * The first DATA packet is full.
  *   * The second DATA packet signals the end of transfer.
  *   * The client handles DATA packets with wrong block numbers
  *     appropriately.
  *   * The test writes a file to the file system with calls to write() of
  *     exactly block size.
  */
 T_TEST_CASE_FIXTURE( write_short_file_bad_block_numbers, &fixture_rfc1350 )
 {
   tftp_test_context *ctx = T_fixture_context();
   int bytes_written;
   uint16_t block_num = 0;
   size_t pos_in_file = 0;
 
   /* T_set_verbosity( T_VERBOSE ); */
   _Tftp_Add_interaction_socket( AF_INET, SOCK_DGRAM, 0, TFTP_FIRST_FD );
   _Tftp_Add_interaction_send_wrq(
     TFTP_FIRST_FD,
     tftpfs_file,
     TFTP_STD_PORT,
     tftpfs_ipv4_loopback,
     NO_BLOCK_SIZE_OPTION,
     NO_WINDOW_SIZE_OPTION,
     true
   );
   _Tftp_Add_interaction_recv_ack(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     block_num + 1, /* Wrong block number */
     true
   );
   _Tftp_Add_interaction_recv_ack(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     block_num++,
     true
   );
   _Tftp_Add_interaction_send_data(
     TFTP_FIRST_FD,
     block_num,
     pos_in_file,
     TFTP_RFC1350_BLOCK_SIZE,
     get_file_content,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     true
   );
   _Tftp_Add_interaction_recv_ack(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     block_num - 1, /* Wrong block number */
     true
   );
   pos_in_file += TFTP_RFC1350_BLOCK_SIZE;
   _Tftp_Add_interaction_recv_ack(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     block_num++,
     true
   );
   _Tftp_Add_interaction_send_data(
     TFTP_FIRST_FD,
     block_num,
     pos_in_file,
     TFTP_RFC1350_BLOCK_SIZE,
     get_file_content,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     true
   );
   _Tftp_Add_interaction_recv_ack(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     block_num - 2, /* Wrong block number */
     true
   );
   pos_in_file += TFTP_RFC1350_BLOCK_SIZE;
   _Tftp_Add_interaction_recv_ack(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     block_num++,
     true
   );
   _Tftp_Add_interaction_send_data(
     TFTP_FIRST_FD,
     block_num,
     pos_in_file,
     TFTP_RFC1350_BLOCK_SIZE / 4,
     get_file_content,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     true
   );
   _Tftp_Add_interaction_recv_ack(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     block_num - 2, /* Wrong block number */
     true
   );
   _Tftp_Add_interaction_recv_ack(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     block_num + 1, /* Wrong block number */
     true
   );
   pos_in_file += TFTP_RFC1350_BLOCK_SIZE / 4;
   _Tftp_Add_interaction_recv_ack(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     block_num++,
     true
   );
   _Tftp_Add_interaction_close( TFTP_FIRST_FD, 0 );
 
   bytes_written = write_tftp_file(
     create_tftpfs_path( tftpfs_ipv4_loopback, tftpfs_file ),
     pos_in_file, /* Size of file */
     TFTP_RFC1350_BLOCK_SIZE, /* Bytes written per call to write() */
     &ctx->fd0
   );
   T_eq_int( bytes_written, pos_in_file );
   T_no_more_interactions();
 }
 
 /*
  * Write a file to the server using only RFC1350.
  * The file is one data packet long.
  * The client receives a stray packet from an unknown server (wrong TID).
  * Directly afterwards the expected ACK packet is lost and
  * the client must retransmit the original DATA packet.
  * Tests:
  *   * The code supports requests without options (RFC1350 only).
  *   * The code supports the use of an IPv4 address instead of a server name.
  *   * The first packet is sent to standard port 69 of server.
  *   * All other packets are sent to the port used for this connection.
  *   * The client uses a short time out for waiting on the answer of the
  *     first DATA packet.
  *   * The client uses a long time out for waiting on the answer of
  *     the repeated DATA.
  *   * Upon reception of a packet with a wrong TID, the client sends
  *     an ERROR message with code 5 but does not terminate the current
  *     transfer.
  *   * When re-transmitting the an packet, the data is intact (i.e.
  *     not corrupted by the reception of any packet in-between).
  */
 T_TEST_CASE_FIXTURE( write_one_block_file_stray_packets, &fixture_rfc1350 )
 {
   tftp_test_context *ctx = T_fixture_context();
   int bytes_written;
   uint16_t block_num = 0;
   size_t pos_in_file = 0;
 
   /* T_set_verbosity( T_VERBOSE ); */
   _Tftp_Add_interaction_socket( AF_INET, SOCK_DGRAM, 0, TFTP_FIRST_FD );
   _Tftp_Add_interaction_send_wrq(
     TFTP_FIRST_FD,
     tftpfs_file,
     TFTP_STD_PORT,
     tftpfs_ipv4_loopback,
     NO_BLOCK_SIZE_OPTION,
     NO_WINDOW_SIZE_OPTION,
     true
   );
   _Tftp_Add_interaction_recv_ack(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     block_num++,
     true
   );
   _Tftp_Add_interaction_send_data(
     TFTP_FIRST_FD,
     block_num,
     pos_in_file,
     TFTP_RFC1350_BLOCK_SIZE,
     get_file_content,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     true
   );
   _Tftp_Add_interaction_recv_data(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT + 1, /* Stray packet with wrong server TID */
     tftpfs_ipv4_loopback,
     block_num,
     0,
     TFTP_RFC1350_BLOCK_SIZE / 2, /* Number of bytes transferred */
     get_bad_file_content,
     true
   );
   _Tftp_Add_interaction_send_error(
     TFTP_FIRST_FD,
     TFTP_ERROR_CODE_UNKNOWN_ID,
     SERV_PORT + 1,
     tftpfs_ipv4_loopback,
     true
   );
   _Tftp_Add_interaction_recv_nothing(
     TFTP_FIRST_FD, /* Timeout: No packet received within timeout period */
     FIRST_TIMEOUT_MILLISECONDS
   );
   _Tftp_Add_interaction_send_data( /* Retransmission of the DATA packet */
     TFTP_FIRST_FD,
     block_num,
     pos_in_file,
     TFTP_RFC1350_BLOCK_SIZE,
     get_file_content,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     true
   );
   pos_in_file += TFTP_RFC1350_BLOCK_SIZE;
   _Tftp_Add_interaction_recv_ack(
     TFTP_FIRST_FD,
     TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     block_num++,
     true
   );
   _Tftp_Add_interaction_send_data(
     TFTP_FIRST_FD,
     block_num,
     pos_in_file,
     0, /* Number of bytes */
     get_file_content,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     true
   );
   pos_in_file += 0;
   _Tftp_Add_interaction_recv_ack(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     block_num++,
     true
   );
   _Tftp_Add_interaction_close( TFTP_FIRST_FD, 0 );
 
   bytes_written = write_tftp_file(
     create_tftpfs_path( tftpfs_ipv4_loopback, tftpfs_file ),
     pos_in_file, /* Size of file */
     TFTP_RFC1350_BLOCK_SIZE, /* Bytes written per call to write() */
     &ctx->fd0
   );
   T_eq_int( bytes_written, pos_in_file );
   T_no_more_interactions();
 }
 
 /*
  * Read a file from the server using option to increase the block size.
  * The file is one data packet long.  No timeouts, packet loss, ...
  * Tests:
  *   * Only the blksize option appears in RRQ and OACK.
  *   * The client uses a block size which is larger than the default size.
  *   * The first data packet is full.
  *   * The second data packet is empty and signals the end of the transfer.
  *   * Client handles the empty data packet correctly as
  *     end of file indicator.
  *   * The test reads a file from the file system in chunks of block size.
  */
 T_TEST_CASE_FIXTURE( read_file_one_large_block, &fixture_large_blocksize )
 {
   tftp_test_context *ctx = T_fixture_context();
   int bytes_read;
   uint16_t block_num = 0;
   size_t pos_in_file = 0;
   const char options[] =
     TFTP_OPTION_BLKSIZE "\0"
     RTEMS_XSTRING( LARGE_BLOCK_SIZE );
 
   /* T_set_verbosity( T_VERBOSE ); */
   _Tftp_Add_interaction_socket( AF_INET, SOCK_DGRAM, 0, TFTP_FIRST_FD );
   _Tftp_Add_interaction_send_rrq(
     TFTP_FIRST_FD,
     tftpfs_file,
     TFTP_STD_PORT,
     tftpfs_ipv4_loopback,
     LARGE_BLOCK_SIZE,
     NO_WINDOW_SIZE_OPTION,
     true
   );
   _Tftp_Add_interaction_recv_oack(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     options,
     sizeof( options ),
     true
   );
   _Tftp_Add_interaction_send_ack(
     TFTP_FIRST_FD,
     block_num++,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     true
   );
   _Tftp_Add_interaction_recv_data(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     block_num,
     pos_in_file,
     LARGE_BLOCK_SIZE, /* Number of bytes transferred */
     get_file_content,
     true
   );
   pos_in_file += LARGE_BLOCK_SIZE;
   _Tftp_Add_interaction_send_ack(
     TFTP_FIRST_FD,
     block_num++,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     true
   );
   _Tftp_Add_interaction_recv_data(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     block_num,
     pos_in_file,
     0, /* Number of bytes transferred */
     get_file_content,
     true
   );
   _Tftp_Add_interaction_send_ack(
     TFTP_FIRST_FD,
     block_num++,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     true
   );
   _Tftp_Add_interaction_close( TFTP_FIRST_FD, 0 );
 
   bytes_read = read_tftp_file(
     create_tftpfs_path( tftpfs_ipv4_loopback, tftpfs_file ),
     LARGE_BLOCK_SIZE, /* Bytes read per call to read() */
     SIZE_MAX,
     &ctx->fd0
   );
   T_eq_int( bytes_read, pos_in_file );
   T_no_more_interactions();
 }
 
 /*
  * Try to read a file from the server using a file name too large for a RRQ.
  * Tests:
  *   * The client rejects an attempt to open a file with a too long
  *     file name is with an error.
  */
 T_TEST_CASE_FIXTURE( read_too_long_file_name, &fixture_default_options )
 {
   tftp_test_context *ctx = T_fixture_context();
   int bytes_read;
   char buffer[TFTP_RFC1350_BLOCK_SIZE -
               strlen( TFTP_MODE_OCTET ) - 1 - 5];
   int len;
 
   /* T_set_verbosity( T_VERBOSE ); */
   _Tftp_Add_interaction_socket( AF_INET, SOCK_DGRAM, 0, TFTP_FIRST_FD );
   _Tftp_Add_interaction_close( TFTP_FIRST_FD, 0 );
 
   len = sizeof( buffer ) - strlen( tftpfs_mount_point ) -
         strlen( tftpfs_ipv4_loopback ) - 2 - 4;
   len = snprintf(
     buffer,
     sizeof( buffer ),
     "%s/%s:%0*d",
     tftpfs_mount_point,
     tftpfs_ipv4_loopback,
     len,
     123
   );
   T_quiet_gt_int( len, 0 );
   T_quiet_lt_int( len, (int) sizeof( buffer ) );
 
   bytes_read = read_tftp_file(
     buffer,
     TFTP_DEFAULT_BLOCK_SIZE, /* Bytes read per call to read() */
     SIZE_MAX,
     &ctx->fd0
   );
   T_eq_int( bytes_read, 0 );
   T_eq_int( errno, ENAMETOOLONG );
   T_no_more_interactions();
 }
 
 /*
  * Read a file using options but the server sends a DATA packet.
  * The file is one byte long.  No timeouts, packet loss, ...
  * Tests:
  *   * The client uses windowsize and blksize option in the RRQ.
  *   * For the data transfer the client uses the RFC1350 option values
  *     because the server responded with a DATA packet.
  *   * The whole package sequence behaves as if only RFC1350 was used.
  *   * The first data packet contains a single byte and signals the end of the transfer.
  *   * The test reads a file from the file system in chunks of half block size.
  */
 T_TEST_CASE_FIXTURE( read_file_DATA_instead_of_OACK, &fixture_default_options )
 {
   tftp_test_context *ctx = T_fixture_context();
   int bytes_read;
   uint16_t block_num = 1;
   size_t pos_in_file = 0;
 
   /* T_set_verbosity( T_VERBOSE ); */
   _Tftp_Add_interaction_socket( AF_INET, SOCK_DGRAM, 0, TFTP_FIRST_FD );
   _Tftp_Add_interaction_send_rrq(
     TFTP_FIRST_FD,
     tftpfs_file,
     TFTP_STD_PORT,
     tftpfs_ipv4_loopback,
     TFTP_DEFAULT_BLOCK_SIZE,
     TFTP_DEFAULT_WINDOW_SIZE,
     true
   );
   _Tftp_Add_interaction_recv_data(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     block_num,
     pos_in_file,
     1, /* Number of bytes transferred */
     get_file_content,
     true
   );
   pos_in_file += 1;
   _Tftp_Add_interaction_send_ack(
     TFTP_FIRST_FD,
     block_num++,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     true
   );
   _Tftp_Add_interaction_close( TFTP_FIRST_FD, 0 );
 
   bytes_read = read_tftp_file(
     create_tftpfs_path( tftpfs_ipv4_loopback, tftpfs_file ),
     TFTP_DEFAULT_BLOCK_SIZE / 2, /* Bytes read per call to read() */
     SIZE_MAX,
     &ctx->fd0
   );
   T_eq_int( bytes_read, pos_in_file );
   T_no_more_interactions();
 }
 
 /*
  * Read a file using RFC1350 but the server sends an OACK packet.
  * Tests:
  *   * The code supports requests without options (RFC1350 only).
  *   * The server wrongly responds with an OACK which contains no options.
  *   * The client sends an error upon reception of an unexpected packet.
  */
 T_TEST_CASE_FIXTURE( read_tiny_file_OACK_instead_of_DATA, &fixture_rfc1350 )
 {
   tftp_test_context *ctx = T_fixture_context();
   int bytes_read;
   const char options[] = {};
 
   /* T_set_verbosity( T_VERBOSE ); */
   _Tftp_Add_interaction_socket( AF_INET, SOCK_DGRAM, 0, TFTP_FIRST_FD );
   _Tftp_Add_interaction_send_rrq(
     TFTP_FIRST_FD,
     tftpfs_file,
     TFTP_STD_PORT,
     tftpfs_ipv4_loopback,
     NO_BLOCK_SIZE_OPTION,
     NO_WINDOW_SIZE_OPTION,
     true
   );
   _Tftp_Add_interaction_recv_oack(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     options,
     sizeof( options ),
     true
   );
   _Tftp_Add_interaction_send_error(
     TFTP_FIRST_FD,
     TFTP_ERROR_CODE_ILLEGAL,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     true
   );
   _Tftp_Add_interaction_close( TFTP_FIRST_FD, 0 );
 
   bytes_read = read_tftp_file(
     create_tftpfs_path( tftpfs_ipv4_loopback, tftpfs_file ),
     1, /* Bytes read per call to read() */
     SIZE_MAX,
     &ctx->fd0
   );
   T_eq_int( bytes_read, 0 );
   T_eq_int( errno, EPROTO );
   T_no_more_interactions();
 }
 
 /*
  * Read a file from the server using the default options.
  * The file is 18 and a half data packet long.  No timeouts, packet loss, ...
  * Tests:
  *   * The client uses the default options
  *     (windowsize = 8 and blocksize = 1456).
  *   * The server send the options in the same order as the client did
  *     send them.
  *   * The ninetenth data packet signals the end of transfer.
  *   * The test reads a file from the file system in chunks of 2000 bytes.
  */
 T_TEST_CASE_FIXTURE( read_file_with_default_options, &fixture_default_options )
 {
   tftp_test_context *ctx = T_fixture_context();
   int i;
   int bytes_read;
   uint16_t block_num = 0;
   size_t pos_in_file = 0;
   const char options[] =
     TFTP_OPTION_BLKSIZE "\0"
     RTEMS_XSTRING( TFTP_DEFAULT_BLOCK_SIZE ) "\0"
     TFTP_OPTION_WINDOWSIZE"\0"
     RTEMS_XSTRING( TFTP_DEFAULT_WINDOW_SIZE );
 
   /* T_set_verbosity( T_VERBOSE ); */
   _Tftp_Add_interaction_socket( AF_INET, SOCK_DGRAM, 0, TFTP_FIRST_FD );
   _Tftp_Add_interaction_send_rrq(
     TFTP_FIRST_FD,
     tftpfs_file,
     TFTP_STD_PORT,
     tftpfs_ipv4_loopback,
     TFTP_DEFAULT_BLOCK_SIZE,
     TFTP_DEFAULT_WINDOW_SIZE,
     true
   );
   _Tftp_Add_interaction_recv_oack(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     options,
     sizeof( options ),
     true
   );
   _Tftp_Add_interaction_send_ack(
     TFTP_FIRST_FD,
     block_num,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     true
   );
   while ( block_num < 16 ) {
     for ( i = 0; i < TFTP_DEFAULT_WINDOW_SIZE; ++i ) {
       _Tftp_Add_interaction_recv_data(
         TFTP_FIRST_FD,
         FIRST_TIMEOUT_MILLISECONDS,
         SERV_PORT,
         tftpfs_ipv4_loopback,
         ++block_num,
         pos_in_file,
         TFTP_DEFAULT_BLOCK_SIZE, /* Number of bytes transferred */
         get_file_content,
         true
       );
       pos_in_file += TFTP_DEFAULT_BLOCK_SIZE;
     }
     _Tftp_Add_interaction_send_ack(
       TFTP_FIRST_FD,
       block_num,
       SERV_PORT,
       tftpfs_ipv4_loopback,
       true
     );
   }
   _Tftp_Add_interaction_recv_data(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     ++block_num,
     pos_in_file,
     TFTP_DEFAULT_BLOCK_SIZE, /* Number of bytes transferred */
     get_file_content,
     true
   );
   pos_in_file += TFTP_DEFAULT_BLOCK_SIZE;
   _Tftp_Add_interaction_recv_data(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     ++block_num,
     pos_in_file,
     TFTP_DEFAULT_BLOCK_SIZE, /* Number of bytes transferred */
     get_file_content,
     true
   );
   pos_in_file += TFTP_DEFAULT_BLOCK_SIZE;
   _Tftp_Add_interaction_recv_data(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     ++block_num,
     pos_in_file,
     TFTP_DEFAULT_BLOCK_SIZE / 2, /* Number of bytes transferred */
     get_file_content,
     true
   );
   pos_in_file += TFTP_DEFAULT_BLOCK_SIZE / 2;
   _Tftp_Add_interaction_send_ack(
     TFTP_FIRST_FD,
     block_num,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     true
   );
   _Tftp_Add_interaction_close( TFTP_FIRST_FD, 0 );
 
   bytes_read = read_tftp_file(
     create_tftpfs_path( tftpfs_ipv4_loopback, tftpfs_file ),
     2000, /* Bytes read per call to read() */
     SIZE_MAX,
     &ctx->fd0
   );
   T_eq_int( bytes_read, pos_in_file );
   T_no_more_interactions();
 }
 
 /*
  * Read a file following exactly the scenario in RFC 7440.
  * This test uses window size and block size options.  There are lost packets.
  * Tests:
  *   * The client uses of non-default options
  *     (windowsize = 4 and blocksize = 12).
  *   * Test the scenario included in RFC 7440.
  *   * When a packet from the server is lost (client receives DATA packet with
  *     a too high block number), the client sends an ACK for the last package
  *     received in the correct sequence.
  *   * The client ignores duplicated packets (with block numbers it has
  *     already processed).
  *   * The data of the file ends exactly at a window size border (i.e.
  *     after the window a single empty DATA packet is sent by the server).
  *   * The test reads a file from the file system in chunks of 10 bytes.
  */
 T_TEST_CASE_FIXTURE( read_file_rfc7440_scenario, &fixture_small_opt_size )
 {
   tftp_test_context *ctx = T_fixture_context();
   int i;
   int bytes_read;
   uint16_t block_num = 0;
   size_t pos_in_file = 0;
   const char options[] =
     TFTP_OPTION_WINDOWSIZE"\0"
     RTEMS_XSTRING( SMALL_WINDOW_SIZE ) "\0"
     TFTP_OPTION_BLKSIZE "\0"
     RTEMS_XSTRING( SMALL_BLOCK_SIZE );
 
   /* T_set_verbosity( T_VERBOSE ); */
   _Tftp_Add_interaction_socket( AF_INET, SOCK_DGRAM, 0, TFTP_FIRST_FD );
   _Tftp_Add_interaction_send_rrq(
     TFTP_FIRST_FD,
     tftpfs_file,
     TFTP_STD_PORT,
     tftpfs_ipv4_loopback,
     SMALL_BLOCK_SIZE,
     SMALL_WINDOW_SIZE,
     true
   );
   _Tftp_Add_interaction_recv_oack(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     options,
     sizeof( options ),
     true
   );
   _Tftp_Add_interaction_send_ack(
     TFTP_FIRST_FD,
     block_num,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     true
   );
   for ( i = 0; i < SMALL_WINDOW_SIZE; ++i ) {
     _Tftp_Add_interaction_recv_data(
       TFTP_FIRST_FD,
       FIRST_TIMEOUT_MILLISECONDS,
       SERV_PORT,
       tftpfs_ipv4_loopback,
       ++block_num,
       pos_in_file,
       SMALL_BLOCK_SIZE, /* Number of bytes transferred */
       get_file_content,
       true
     );
     pos_in_file += SMALL_BLOCK_SIZE;
   }
   _Tftp_Add_interaction_send_ack(
     TFTP_FIRST_FD,
     block_num,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     true
   );
   _Tftp_Add_interaction_recv_data(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     ++block_num,
     pos_in_file,
     SMALL_BLOCK_SIZE, /* Number of bytes transferred */
     get_file_content,
     true
   );
   pos_in_file += SMALL_BLOCK_SIZE;
   _Tftp_Add_interaction_recv_data(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     block_num + 2, /* Error: One packet from the server has been lost */
     pos_in_file,
     SMALL_BLOCK_SIZE, /* Number of bytes transferred */
     get_file_content,
     true
   );
   _Tftp_Add_interaction_send_ack(
     TFTP_FIRST_FD,
     block_num,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     true
   );
   for ( i = 0; i < SMALL_WINDOW_SIZE; ++i ) {
     _Tftp_Add_interaction_recv_data(
       TFTP_FIRST_FD,
       FIRST_TIMEOUT_MILLISECONDS,
       SERV_PORT,
       tftpfs_ipv4_loopback,
       ++block_num,
       pos_in_file,
       SMALL_BLOCK_SIZE, /* Number of bytes transferred */
       get_file_content,
       true
     );
     pos_in_file += SMALL_BLOCK_SIZE;
   }
   _Tftp_Add_interaction_send_ack(
     TFTP_FIRST_FD,
     block_num,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     true
   );
   _Tftp_Add_interaction_recv_data(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     ++block_num,
     pos_in_file,
     SMALL_BLOCK_SIZE, /* Number of bytes transferred */
     get_file_content,
     true
   );
   pos_in_file += SMALL_BLOCK_SIZE;
   _Tftp_Add_interaction_recv_data(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     block_num + 2, /* Error: One packet from the server has been lost */
     pos_in_file,
     SMALL_BLOCK_SIZE, /* Number of bytes transferred */
     get_file_content,
     true
   );
   _Tftp_Add_interaction_send_ack(
     TFTP_FIRST_FD,
     block_num, /* The packet is assumed to be lost/does not reach the server */
     SERV_PORT,
     tftpfs_ipv4_loopback,
     true
   );
   _Tftp_Add_interaction_recv_data(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     block_num + 3, /* Error: One packet from the server has been lost */
     pos_in_file,
     SMALL_BLOCK_SIZE, /* Number of bytes transferred */
     get_file_content,
     true
   );
   block_num = 9; /* The ACK for DATA packet 10 did not reach the server */
   pos_in_file = block_num * SMALL_BLOCK_SIZE;
   for ( i = 0; i < SMALL_WINDOW_SIZE; ++i ) {
     _Tftp_Add_interaction_recv_data(
       TFTP_FIRST_FD,
       FIRST_TIMEOUT_MILLISECONDS,
       SERV_PORT,
       tftpfs_ipv4_loopback,
       ++block_num,
       pos_in_file,
       SMALL_BLOCK_SIZE, /* Number of bytes transferred */
       get_file_content,
       true
     );
     pos_in_file += SMALL_BLOCK_SIZE;
   }
   _Tftp_Add_interaction_send_ack(
     TFTP_FIRST_FD,
     block_num,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     true
   );
   _Tftp_Add_interaction_recv_data(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     ++block_num,
     pos_in_file,
     0, /* Number of bytes transferred */
     get_file_content,
     true
   );
   _Tftp_Add_interaction_send_ack(
     TFTP_FIRST_FD,
     block_num,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     true
   );
   _Tftp_Add_interaction_close( TFTP_FIRST_FD, 0 );
 
   bytes_read = read_tftp_file(
     create_tftpfs_path( tftpfs_ipv4_loopback, tftpfs_file ),
     10, /* Bytes read per call to read() */
     SIZE_MAX,
     &ctx->fd0
   );
   T_eq_int( bytes_read, pos_in_file );
   T_no_more_interactions();
 }
 
 /*
  * Read a file using windowsize = 4.  All kinds of packet loss, out of order
  * packets and duplicated packets occur.
  * This test uses window size and block size options.  It is a stress test
  * for all kind of network problems which can appear during a transfer
  * of a file with window size larger than 1.
  * Tests:
  *   * The client uses non-default options (windowsize = 4 and blocksize = 12).
  *   * The first DATA packet of a window is lost.
  *   * The last DATA packet of a window is lost.
  *   * The middle DATA packets of a window is lost.
  *   * The first two DATA packets of a window are received in reverse order.
  *   * The middle two DATA packets of a window are received in reverse order.
  *   * The last two DATA packets of a window are received in reverse order.
  *   * The a DATA packet is received duplicated.
  *   * The an old DATA packet is received duplicated.
  *   * The a very old DATA packet is received duplicated.
  *   * The normal ACK of a window is not received by the server.
  *   * The server repeats a whole window (ensure the client sends an ACK
  *     packet despite of the repetition).
  *   * An ACK for an out-of-order packet is not received by the server.
  *   * Windows with errors appear consecutively without
  *     error free windows in between.
  *   * After the reception of the first two DATA packets of a window,
  *     a timeout occurs and the client must send an ACK.
  *   * File transfer ends exactly with the last packet of a window
  *     (the second last packet is full and the last one is empty).
  *   * The test reads a file from the file system in chunks 100 bytes.
  */
 T_TEST_CASE_FIXTURE( read_file_windowsize_trouble, &fixture_small_opt_size )
 {
   tftp_test_context *ctx = T_fixture_context();
   int i;
   int bytes_read;
   uint16_t block_num = 0;
   size_t pos_in_file = 0;
   int timeout = FIRST_TIMEOUT_MILLISECONDS;
   const char options[] =
     TFTP_OPTION_WINDOWSIZE"\0"
     RTEMS_XSTRING( SMALL_WINDOW_SIZE ) "\0"
     TFTP_OPTION_BLKSIZE "\0"
     RTEMS_XSTRING( SMALL_BLOCK_SIZE );
   /*
    * A positive number is the number of a DATA packet received.
    * A negative number is the number of an ACK packet send.
    * A zero indicates a timeout when waiting for a DATA packet.
    * Each line corresponds to a window.
    */
   int16_t pkg_sequence[] = {
     1, 1, 2, 3, 2, 1, 3, 4, -4, /* Duplicated DATA packets */
     6, -4, 7, 8, /* DATA packet 5 lost */
     6, 5, 7, -5, 4, 8, /* DATA packet 5 and 6 received in revers order;
                           reception of an very old packet: 4 */
     7, 6, 8, -6, /* DATA packet 6 and 7 received in revers order;
                     DATA packet 9 not send or lost */
     6, 7, 8, 9, -9, /* ACK packet 6 was not received by server */
     10, 11, 12, 0, -12, /* DATA packet 13 lost */
     13, 16, -13, /* DATA packets 14, 15 lost */
     12, 13, 14, 15, -15, 16, 17, /* Reception of duplicated old packets 12 and
                                     13 */
     16, 17, 18, 19, -19, /* Normal sequence; ACK 19 not receive by server */
     16, 17, 18, 19, -19, /* Normal sequence repeated;
                             ACK 19 not receive by server */
     16, 19, -19, 18, 17, /* Sequence repeated but DATA packet 17 and 18
                             received after 19 and in revers order */
     20, -20, 21, 22, 23, /* ACK 20 because the client assumes the server
                             did not get ACK 19 and restarted with 17 */
     21, 22, 23, 24, -24, /* Normal sequence */
     25, 27, -25, 26, 28, -26, /* The middle data packets 26, 27 are exchanged;
                                  the client assumes DATA 26 being the start
                                  of the next window and sends an ACK 26
                                  upon reception of out-of-sequence DATA 28;
                                  assume ACK 26 not received by server */
     26, 27, 29, -27, 28, /* The last data packets are exchanged;
                             ACK 27 not received by server */
     26, 27, 28, 29, -29, /* Normal sequence repeated from ACK 25 */
     30, 31, 0, -31, /* The last two data packets are lost (timeout) */
     32, 33, 34, /* Normal sequence; the last DATA packet (here missing) will
                    contain no data and ends the transfer at a window
                    boundary; a final ACK (here missing too) follows */
   };
 
   /* T_set_verbosity( T_VERBOSE ); */
   _Tftp_Add_interaction_socket( AF_INET, SOCK_DGRAM, 0, TFTP_FIRST_FD );
   _Tftp_Add_interaction_send_rrq(
     TFTP_FIRST_FD,
     tftpfs_file,
     TFTP_STD_PORT,
     tftpfs_ipv4_loopback,
     SMALL_BLOCK_SIZE,
     SMALL_WINDOW_SIZE,
     true
   );
   _Tftp_Add_interaction_recv_oack(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     options,
     sizeof( options ),
     true
   );
   _Tftp_Add_interaction_send_ack(
     TFTP_FIRST_FD,
     block_num,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     true
   );
   for ( i = 0; i < RTEMS_ARRAY_SIZE( pkg_sequence ); ++i ) {
     if ( pkg_sequence[i] == 0 ) {
       block_num = pkg_sequence[i];
       _Tftp_Add_interaction_recv_nothing(
         TFTP_FIRST_FD, /* Timeout: No packet received within timeout period */
         timeout
       );
       timeout = TIMEOUT_MILLISECONDS;
     } else if ( pkg_sequence[i] > 0 ) {
       block_num = pkg_sequence[i];
       _Tftp_Add_interaction_recv_data(
         TFTP_FIRST_FD,
         timeout,
         SERV_PORT,
         tftpfs_ipv4_loopback,
         block_num,
         ( block_num - 1 ) * SMALL_BLOCK_SIZE,
         SMALL_BLOCK_SIZE, /* Number of bytes transferred */
         get_file_content,
         pkg_sequence[i] > 0 /* pkg_sequence[i] == 0 means timeout */
       );
       timeout = FIRST_TIMEOUT_MILLISECONDS;
       pos_in_file = block_num * SMALL_BLOCK_SIZE;
     } else {
       block_num = -pkg_sequence[i];
       _Tftp_Add_interaction_send_ack(
         TFTP_FIRST_FD,
         block_num,
         SERV_PORT,
         tftpfs_ipv4_loopback,
         true
       );
     }
   }
   _Tftp_Add_interaction_recv_data(
     TFTP_FIRST_FD,
     timeout,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     ++block_num,
     pos_in_file,
     0, /* Number of bytes transferred */
     get_file_content,
     true
   );
   _Tftp_Add_interaction_send_ack(
     TFTP_FIRST_FD,
     block_num,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     true
   );
   _Tftp_Add_interaction_close( TFTP_FIRST_FD, 0 );
 
   bytes_read = read_tftp_file(
     create_tftpfs_path( tftpfs_ipv4_loopback, tftpfs_file ),
     100, /* Bytes read per call to read() */
     SIZE_MAX,
     &ctx->fd0
   );
   T_eq_int( bytes_read, pos_in_file );
   T_no_more_interactions();
 }
 
 /*
  * Write a file to the server using an option to increase block size.
  * The file is 2 DATA packet and 1 byte long.  No timeouts, packet loss, ...
  * Tests:
  *   * The client uses only the blksize option in WRQ and OACK.
  *   * The client uses a block size which is larger than the default size.
  *   * The server can change the block size value in the OACK.
  *   * The option name in the OACK can be upper or lower case.
  *   * First and second DATA packets are full.
  *   * The second DATA packet is not full and signals the end of the transfer.
  *   * The client handles an empty DATA packet correctly as
  *     end of file indicator.
  *   * The test writes the file to the file system in chunks of 333 bytes.
  */
 T_TEST_CASE_FIXTURE( write_simple_file_large_blocks, &fixture_large_blocksize )
 {
   tftp_test_context *ctx = T_fixture_context();
   int bytes_written;
   size_t pos_in_file = 0;
   uint16_t block_num = 1;
   uint16_t block_size = 211;
   const char options[] = "BLKsiZe" "\0" "211";
 
   /* T_set_verbosity( T_VERBOSE ); */
   _Tftp_Add_interaction_socket( AF_INET, SOCK_DGRAM, 0, TFTP_FIRST_FD );
   _Tftp_Add_interaction_send_wrq(
     TFTP_FIRST_FD,
     tftpfs_file,
     TFTP_STD_PORT,
     tftpfs_ipv4_loopback,
     LARGE_BLOCK_SIZE,
     NO_WINDOW_SIZE_OPTION,
     true
   );
   _Tftp_Add_interaction_recv_oack(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     options,
     sizeof( options ),
     true
   );
   _Tftp_Add_interaction_send_data(
     TFTP_FIRST_FD,
     block_num,
     pos_in_file,
     block_size,
     get_file_content,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     true
   );
   pos_in_file += block_size;
   _Tftp_Add_interaction_recv_ack(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     block_num++,
     true
   );
   _Tftp_Add_interaction_send_data(
     TFTP_FIRST_FD,
     block_num,
     pos_in_file,
     block_size,
     get_file_content,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     true
   );
   pos_in_file += block_size;
   _Tftp_Add_interaction_recv_ack(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     block_num++,
     true
   );
   _Tftp_Add_interaction_send_data(
     TFTP_FIRST_FD,
     block_num,
     pos_in_file,
     1, /* Data bytes in this block */
     get_file_content,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     true
   );
   pos_in_file += 1;
   _Tftp_Add_interaction_recv_ack(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     block_num++,
     true
   );
   _Tftp_Add_interaction_close( TFTP_FIRST_FD, 0 );
 
   bytes_written = write_tftp_file(
     create_tftpfs_path( tftpfs_ipv4_loopback, tftpfs_file ),
     pos_in_file, /* Size of file */
     333, /* Bytes written per call to write() */
     &ctx->fd0
   );
   T_eq_int( bytes_written, pos_in_file );
   T_no_more_interactions();
 }
 
 /*
  * Write a file to the server using default options.
  * The file is 23 data packet long.  No timeouts, packet loss, ...
  * Tests:
  *   * The client uses the default options
  *     (windowsize = 8 and blocksize = 1456).
  *   * The server sends the options in the same order the client
  *     did send them.
  *   * The 24th data packet signals the end of file transfer.
  *   * Client sends an empty data packet as end of file indicator.
  *   * The client handles files correctly which end exactly at
  *     a window border.
  */
 T_TEST_CASE_FIXTURE(
   write_simple_file_default_options,
   &fixture_default_options
 )
 {
   tftp_test_context *ctx = T_fixture_context();
   int i;
   int bytes_written;
   size_t pos_in_file = 0;
   uint16_t block_num = 1;
   const char options[] =
     TFTP_OPTION_BLKSIZE "\0"
     RTEMS_XSTRING( TFTP_DEFAULT_BLOCK_SIZE ) "\0"
     TFTP_OPTION_WINDOWSIZE "\0"
     RTEMS_XSTRING( TFTP_DEFAULT_WINDOW_SIZE );
 
   /* T_set_verbosity( T_VERBOSE ); */
   _Tftp_Add_interaction_socket( AF_INET, SOCK_DGRAM, 0, TFTP_FIRST_FD );
   _Tftp_Add_interaction_send_wrq(
     TFTP_FIRST_FD,
     tftpfs_file,
     TFTP_STD_PORT,
     tftpfs_ipv4_loopback,
     TFTP_DEFAULT_BLOCK_SIZE,
     TFTP_DEFAULT_WINDOW_SIZE,
     true
   );
   _Tftp_Add_interaction_recv_oack(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     options,
     sizeof( options ),
     true
   );
   for ( i = 0; i < 23; ++i ) {
     _Tftp_Add_interaction_send_data(
       TFTP_FIRST_FD,
       block_num++,
       pos_in_file,
       TFTP_DEFAULT_BLOCK_SIZE,
       get_file_content,
       SERV_PORT,
       tftpfs_ipv4_loopback,
       true
     );
     pos_in_file += TFTP_DEFAULT_BLOCK_SIZE;
     if ( i % 8 == 7 ) {
       _Tftp_Add_interaction_recv_ack(
         TFTP_FIRST_FD,
         FIRST_TIMEOUT_MILLISECONDS,
         SERV_PORT,
         tftpfs_ipv4_loopback,
         block_num - 1,
         true
       );
     } else {
       _Tftp_Add_interaction_recv_nothing(
         TFTP_FIRST_FD,
         DO_NOT_WAIT_FOR_ANY_TIMEOUT
       );
     }
   }
   _Tftp_Add_interaction_send_data(
     TFTP_FIRST_FD,
     block_num,
     pos_in_file,
     0,
     get_file_content,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     true
   );
   _Tftp_Add_interaction_recv_ack(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     block_num++,
     true
   );
   _Tftp_Add_interaction_close( TFTP_FIRST_FD, 0 );
 
   bytes_written = write_tftp_file(
     create_tftpfs_path( tftpfs_ipv4_loopback, tftpfs_file ),
     pos_in_file, /* Size of file */
     333, /* Bytes written per call to write() */
     &ctx->fd0
   );
   T_eq_int( bytes_written, pos_in_file );
   T_no_more_interactions();
 }
 
 /*
  * Write a file following exactly the scenario from RFC 7440.
  * This test uses window size and block size options.  There are lost packets.
  * Tests:
  *   * The client uses non-default options
  *     (windowsize = 4 and blocksize = 12).
  *   * Test the scenario included in RFC 7440.
  *   * The server sends the options in the inverse order the client
  *     did send them.
  *   * The data of the file ends exactly at a window size border (i.e.
  *     after the last window the server sends a single empty DATA packet).
  *   * The test writes a file to the file system in chunks of 10 bytes.
  */
 T_TEST_CASE_FIXTURE( write_file_rfc7440_scenario, &fixture_small_opt_size )
 {
   tftp_test_context *ctx = T_fixture_context();
   int i;
   int bytes_written;
   size_t pos_in_file = 0;
   uint16_t block_num = 1;
   const char options[] =
     TFTP_OPTION_WINDOWSIZE"\0"
     RTEMS_XSTRING( SMALL_WINDOW_SIZE ) "\0"
     TFTP_OPTION_BLKSIZE "\0"
     RTEMS_XSTRING( SMALL_BLOCK_SIZE );
 
   /* T_set_verbosity( T_VERBOSE ); */
   _Tftp_Add_interaction_socket( AF_INET, SOCK_DGRAM, 0, TFTP_FIRST_FD );
   _Tftp_Add_interaction_send_wrq(
     TFTP_FIRST_FD,
     tftpfs_file,
     TFTP_STD_PORT,
     tftpfs_ipv4_loopback,
     SMALL_BLOCK_SIZE,
     SMALL_WINDOW_SIZE,
     true
   );
   _Tftp_Add_interaction_recv_oack(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     options,
     sizeof( options ),
     true
   );
   for ( i = 0; i < 6; ++i ) {
     _Tftp_Add_interaction_send_data(
       TFTP_FIRST_FD,
       block_num++,
       pos_in_file,
       SMALL_BLOCK_SIZE,
       get_file_content,
       SERV_PORT,
       tftpfs_ipv4_loopback,
       true
     );
     pos_in_file += SMALL_BLOCK_SIZE;
     if ( i % 4 == 3 ) {
       _Tftp_Add_interaction_recv_ack(
         TFTP_FIRST_FD,
         FIRST_TIMEOUT_MILLISECONDS,
         SERV_PORT,
         tftpfs_ipv4_loopback,
         block_num - 1,
         true
       );
     } else {
       _Tftp_Add_interaction_recv_nothing(
         TFTP_FIRST_FD,
         DO_NOT_WAIT_FOR_ANY_TIMEOUT
       );
     }
   }
   _Tftp_Add_interaction_send_data(
     TFTP_FIRST_FD,
     block_num,
     pos_in_file,
     SMALL_BLOCK_SIZE,
     get_file_content,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     true
   );
   _Tftp_Add_interaction_recv_ack(
     TFTP_FIRST_FD,
     DO_NOT_WAIT_FOR_ANY_TIMEOUT,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     5,
     true
   );
   block_num = 6;
   pos_in_file = (block_num - 1) * SMALL_BLOCK_SIZE;
   for ( i = 0; i < 7; ++i ) {
     _Tftp_Add_interaction_send_data(
       TFTP_FIRST_FD,
       block_num++,
       pos_in_file,
       SMALL_BLOCK_SIZE,
       get_file_content,
       SERV_PORT,
       tftpfs_ipv4_loopback,
       true
     );
     pos_in_file += SMALL_BLOCK_SIZE;
     if ( i % 4 == 3 ) {
       _Tftp_Add_interaction_recv_ack(
         TFTP_FIRST_FD,
         FIRST_TIMEOUT_MILLISECONDS,
         SERV_PORT,
         tftpfs_ipv4_loopback,
         block_num - 1,
         true
       );
     } else {
       _Tftp_Add_interaction_recv_nothing(
         TFTP_FIRST_FD,
         DO_NOT_WAIT_FOR_ANY_TIMEOUT
       );
     }
   }
   _Tftp_Add_interaction_send_data(
     TFTP_FIRST_FD,
     block_num,
     pos_in_file,
     SMALL_BLOCK_SIZE,
     get_file_content,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     true
   );
   _Tftp_Add_interaction_recv_nothing(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS
   );
   block_num = 10;
   pos_in_file = (block_num - 1) * SMALL_BLOCK_SIZE;
   for ( i = 0; i < 4; ++i ) {
     _Tftp_Add_interaction_send_data(
       TFTP_FIRST_FD,
       block_num++,
       pos_in_file,
       SMALL_BLOCK_SIZE,
       get_file_content,
       SERV_PORT,
       tftpfs_ipv4_loopback,
       true
     );
     pos_in_file += SMALL_BLOCK_SIZE;
     if ( i % 4 == 3 ) {
       _Tftp_Add_interaction_recv_ack(
         TFTP_FIRST_FD,
         FIRST_TIMEOUT_MILLISECONDS,
         SERV_PORT,
         tftpfs_ipv4_loopback,
         block_num - 1,
         true
       );
     } else {
       _Tftp_Add_interaction_recv_nothing(
         TFTP_FIRST_FD,
         DO_NOT_WAIT_FOR_ANY_TIMEOUT
       );
     }
   }
   _Tftp_Add_interaction_send_data(
     TFTP_FIRST_FD,
     block_num,
     pos_in_file,
     0,
     get_file_content,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     true
   );
   _Tftp_Add_interaction_recv_ack(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     block_num++,
     true
   );
   _Tftp_Add_interaction_close( TFTP_FIRST_FD, 0 );
 
   bytes_written = write_tftp_file(
     create_tftpfs_path( tftpfs_ipv4_loopback, tftpfs_file ),
     pos_in_file, /* Size of file */
     10, /* Bytes written per call to write() */
     &ctx->fd0
   );
   T_eq_int( bytes_written, pos_in_file );
   T_no_more_interactions();
 }
 
 /*
  * Write a file using windowsize = 4.  All kinds of packet loss, out of
  * order packets and duplicated ACK packets appear.
  * This test uses window size and block size options.  It is a stress test
  * for all kind of network problems which can appear during a transfer
  * of a file with window size larger than 1.
  * Tests:
  *   * The server repeats a whole window (timeout).
  *   * The client receives a duplicated ACK packet (directly in sequence).
  *   * The client receives a duplicated ACK (after sending a window).
  *   * The client receives an ACK with a block number which is not
  *     the end of the current window.
  *   * The client receives an very old ACK in the middle of a window.
  *   * The client receives an very old ACK at the end of a window.
  *   * The client receives an ACK for a not yet send DATA packet in the
  *     middle of a window (should be ignored or cause a error).
  *   * The client receives an ACK for a not yet send DATA packet at the
  *     end of a window (should be ignored or cause a error).
  *   * The client receives an ACK after sending a full window.
  *   * The client receives an ACK before all DATA packets of a
  *     window have been sent.
  *   * The client must repeat the first window completely (timeout).
  *   * The client must repeat the first window partially.
  *   * The client must repeat the last window completely (timeout).
  *   * The client must repeat the last window partially.
  *   * Windows with errors in between appear consecutively, without
  *     error free windows in between.
  *   * The test writes a file to the file system in chunks of block size.
  */
 T_TEST_CASE_FIXTURE( write_file_windowsize_trouble, &fixture_small_opt_size )
 {
   tftp_test_context *ctx = T_fixture_context();
   int i;
   int bytes_written;
   size_t pos_in_file = 0;
   uint16_t block_num = 1;
   int timeout = FIRST_TIMEOUT_MILLISECONDS;
   const char options[] =
     TFTP_OPTION_BLKSIZE "\0"
     RTEMS_XSTRING( SMALL_BLOCK_SIZE ) "\0"
     TFTP_OPTION_WINDOWSIZE"\0"
     RTEMS_XSTRING( SMALL_WINDOW_SIZE );
   /*
    * A positive number is the number of an ACK packet received
    *   at the end of window.
    * A 9999 indicates a timeout when waiting for an ACK packet.
    * A zero indicates no ACK packet is received when checking for it.
    * A positive number >= 10000 is the number+10000 of an ACK packet received
    *   while only checking for a packet.
    * A negative number is the number of a DATA packet send
    *   at the end of a window.
    * A negative number <= -10000 is the number-10000 of an *empty* DATA
    *   packet send.
    * Each line corresponds to a window.
    */
   int16_t pkg_sequence[] = {
     -1, 0, -2, 0, -3, 0, -4, 9999, /* First window, trigger full repeat */
     -1, 0, -2, 0, -3, 0, -4, 2, /* ACK at end of window;
                                    first window must be partially repeated */
     -3, 0, -4, 0, -5, 0, -6, 6, /* Normal sequence */
     -7, 0, -8, 0, -9, 0, -10, 6, /* Duplicate ACK */
     -7, 10006, /* Duplicate ACK; ACK before sending all packets of a window */
     -7, 0, -8, 10008, /* ACK before sending all packets of a window;
                          ACK is not at the window end */
     -9, 10007, 0, -10, 10013, 0, -11, 0, -12, 12, /* Reception of very old ACK;
                                                     Reception of future ACK (The
                                                     wrong "future" ACK must be
                                                     beyond the block size)
                                                     in the middle of a window */
     -13, 0, -14, 0, -15, 0, -16, 11, 17, 16, /* Reception of very old ACK;
                                                 Reception of future ACK at the
                                                 end of a window */
     -17, 0, -18, 0, -10019, 9999, /* Last window timeout, trigger full repeat */
     -17, 0, -18, 0, -10019, 16, /* Last window, duplicated ACK */
     -17, 0, -18, 10017, /* Last window, ACK before sending all packets */
     -18, 0, -10019, 19 /* Last window partially repeated */
   };
 
   /* T_set_verbosity( T_VERBOSE ); */
   _Tftp_Add_interaction_socket( AF_INET, SOCK_DGRAM, 0, TFTP_FIRST_FD );
   _Tftp_Add_interaction_send_wrq(
     TFTP_FIRST_FD,
     tftpfs_file,
     TFTP_STD_PORT,
     tftpfs_ipv4_loopback,
     SMALL_BLOCK_SIZE,
     SMALL_WINDOW_SIZE,
     true
   );
   _Tftp_Add_interaction_recv_oack(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     options,
     sizeof( options ),
     true
   );
   for ( i = 0; i < RTEMS_ARRAY_SIZE( pkg_sequence ); ++i ) {
     if ( pkg_sequence[i] == 0 ) {
       _Tftp_Add_interaction_recv_nothing(
         TFTP_FIRST_FD,
         DO_NOT_WAIT_FOR_ANY_TIMEOUT
       );
       timeout = FIRST_TIMEOUT_MILLISECONDS;
     } else if ( pkg_sequence[i] == 9999 ) {
       _Tftp_Add_interaction_recv_nothing(
         TFTP_FIRST_FD,
         timeout
       );
       timeout = FIRST_TIMEOUT_MILLISECONDS;
     } else if ( pkg_sequence[i] >= 10000 ) {
       block_num = pkg_sequence[i] - 10000;
       _Tftp_Add_interaction_recv_ack(
         TFTP_FIRST_FD,
         DO_NOT_WAIT_FOR_ANY_TIMEOUT,
         SERV_PORT,
         tftpfs_ipv4_loopback,
         block_num++,
         true
       );
       timeout = FIRST_TIMEOUT_MILLISECONDS;
     } else if ( pkg_sequence[i] > 0 ) {
       block_num = pkg_sequence[i];
       _Tftp_Add_interaction_recv_ack(
         TFTP_FIRST_FD,
         timeout,
         SERV_PORT,
         tftpfs_ipv4_loopback,
         block_num++,
         true
       );
       timeout = FIRST_TIMEOUT_MILLISECONDS;
     } else if ( pkg_sequence[i] <= -10000 ) {
       block_num = -pkg_sequence[i] - 10000;
       pos_in_file = (block_num - 1) * SMALL_BLOCK_SIZE;
       _Tftp_Add_interaction_send_data(
         TFTP_FIRST_FD,
         block_num++,
         pos_in_file,
         0, /* Number of bytes transferred */
         get_file_content,
         SERV_PORT,
         tftpfs_ipv4_loopback,
         true
       );
       timeout = FIRST_TIMEOUT_MILLISECONDS;
     } else {
       block_num = -pkg_sequence[i];
       pos_in_file = (block_num - 1) * SMALL_BLOCK_SIZE;
       _Tftp_Add_interaction_send_data(
         TFTP_FIRST_FD,
         block_num++,
         pos_in_file,
         SMALL_BLOCK_SIZE,
         get_file_content,
         SERV_PORT,
         tftpfs_ipv4_loopback,
         true
       );
       timeout = FIRST_TIMEOUT_MILLISECONDS;
       pos_in_file += SMALL_BLOCK_SIZE;
     }
   }
   _Tftp_Add_interaction_close( TFTP_FIRST_FD, 0 );
 
   bytes_written = write_tftp_file(
     create_tftpfs_path( tftpfs_ipv4_loopback, tftpfs_file ),
     pos_in_file, /* Size of file */
     SMALL_BLOCK_SIZE, /* Bytes written per call to write() */
     &ctx->fd0
   );
   T_eq_int( bytes_written, pos_in_file );
   T_no_more_interactions();
 }
 
 /*
  * Write a file to the server where the server sends an OACK without options.
  * The file is half a data packet long.  No timeouts, packet loss, ...
  * Tests:
  *   * The client processes an OACK without any options in it correctly.
  *   * The client uses the RFC1350 block size because the server does
  *     not agree to the options send.
  *   * The first data packet is half full and signals the end of the transfer.
  *   * The test reads a file from the file system in chunks of double block size.
  */
 T_TEST_CASE_FIXTURE( write_tiny_file_OACK_no_options, &fixture_large_blocksize )
 {
   tftp_test_context *ctx = T_fixture_context();
   int bytes_written;
   size_t pos_in_file = 0;
   uint16_t block_num = 1;
   const char options[] = {};
 
   /* T_set_verbosity( T_VERBOSE ); */
   _Tftp_Add_interaction_socket( AF_INET, SOCK_DGRAM, 0, TFTP_FIRST_FD );
   _Tftp_Add_interaction_send_wrq(
     TFTP_FIRST_FD,
     tftpfs_file,
     TFTP_STD_PORT,
     tftpfs_ipv4_loopback,
     LARGE_BLOCK_SIZE,
     NO_WINDOW_SIZE_OPTION,
     true
   );
   _Tftp_Add_interaction_recv_oack(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     options,
     sizeof( options ),
     true
   );
   _Tftp_Add_interaction_send_data(
     TFTP_FIRST_FD,
     block_num,
     pos_in_file,
     TFTP_RFC1350_BLOCK_SIZE / 2,
     get_file_content,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     true
   );
   pos_in_file += TFTP_RFC1350_BLOCK_SIZE / 2;
   _Tftp_Add_interaction_recv_ack(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     block_num++,
     true
   );
   _Tftp_Add_interaction_close( TFTP_FIRST_FD, 0 );
 
   bytes_written = write_tftp_file(
     create_tftpfs_path( tftpfs_ipv4_loopback, tftpfs_file ),
     pos_in_file, /* Size of file */
     2 * TFTP_RFC1350_BLOCK_SIZE, /* Bytes written per call to write() */
     &ctx->fd0
   );
   T_eq_int( bytes_written, pos_in_file );
   T_no_more_interactions();
 }
 
 /*
  * Read a file and when the server responses with an ERROR to options
  * fallback to no options.
  * The file is one byte long.  No timeouts, packet loss, ...
  * Tests:
  *   * The client uses windowsize and blksize option in the first RRQ.
  *   * Upon reception of an ERROR packet from the server, the client
  *     re-tries opening the session using an RRQ without options.
  *   * The server accepts the RRQ without options by sending a DATA packet.
  *   * The second RRQ is sent to the TFTP server port 69 and not to the
  *     port from which the first ERROR packet came from.
  *   * The first data packet contains a single byte and signals the
  *     end of the transfer.
  */
 T_TEST_CASE_FIXTURE( read_file_fallback_to_no_options,
   &fixture_default_options )
 {
   tftp_test_context *ctx = T_fixture_context();
   int bytes_read;
   uint16_t block_num = 1;
   size_t pos_in_file = 0;
 
   /* T_set_verbosity( T_VERBOSE ); */
   _Tftp_Add_interaction_socket( AF_INET, SOCK_DGRAM, 0, TFTP_FIRST_FD );
   _Tftp_Add_interaction_send_rrq(
     TFTP_FIRST_FD,
     tftpfs_file,
     TFTP_STD_PORT,
     tftpfs_ipv4_loopback,
     TFTP_DEFAULT_BLOCK_SIZE,
     TFTP_DEFAULT_WINDOW_SIZE,
     true
   );
   _Tftp_Add_interaction_recv_error(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     TFTP_ERROR_CODE_OPTION_NEGO,
     "Don't like options",
     true
   );
   _Tftp_Add_interaction_send_rrq(
     TFTP_FIRST_FD,
     tftpfs_file,
     TFTP_STD_PORT,
     tftpfs_ipv4_loopback,
     NO_BLOCK_SIZE_OPTION,
     NO_WINDOW_SIZE_OPTION,
     true
   );
   _Tftp_Add_interaction_recv_data(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     block_num,
     pos_in_file,
     1, /* Number of bytes transferred */
     get_file_content,
     true
   );
   pos_in_file += 1;
   _Tftp_Add_interaction_send_ack(
     TFTP_FIRST_FD,
     block_num++,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     true
   );
   _Tftp_Add_interaction_close( TFTP_FIRST_FD, 0 );
 
   bytes_read = read_tftp_file(
     create_tftpfs_path( tftpfs_ipv4_loopback, tftpfs_file ),
     TFTP_DEFAULT_BLOCK_SIZE / 2, /* Bytes read per call to read() */
     SIZE_MAX,
     &ctx->fd0
   );
   T_eq_int( bytes_read, pos_in_file );
   T_no_more_interactions();
 }
 
 /*
  * Read a file from the server but the server responds with
  * an ERROR to all RRQ with and without options.
  * The file is one byte long.  No timeouts, packet loss, ...
  * Tests:
  *   * The client uses windowsize and blksize option in the first RRQ.
  *   * Upon reception of an ERROR packet from the server, the client
  *     re-tries opening a session using an RRQ without options.
  *   * The second RRQ is sent to the TFTP server port 69 and not to the
  *     port from which the first ERROR packet came from.
  *   * The server does not accept the RRQ without options
  *     and responds again with an ERROR packet.
  *   * The client ends all attempts to create a connection after
  *     receiving an ERROR packet to an RRQ without options.
  *   * The client signals the error to the user.
  */
 T_TEST_CASE_FIXTURE( read_file_useless_fallback_to_no_options,
   &fixture_default_options )
 {
   tftp_test_context *ctx = T_fixture_context();
   int bytes_read;
 
   /* T_set_verbosity( T_VERBOSE ); */
   _Tftp_Add_interaction_socket( AF_INET, SOCK_DGRAM, 0, TFTP_FIRST_FD );
   _Tftp_Add_interaction_send_rrq(
     TFTP_FIRST_FD,
     tftpfs_file,
     TFTP_STD_PORT,
     tftpfs_ipv4_loopback,
     TFTP_DEFAULT_BLOCK_SIZE,
     TFTP_DEFAULT_WINDOW_SIZE,
     true
   );
   _Tftp_Add_interaction_recv_error(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     TFTP_ERROR_CODE_ILLEGAL,
     "Don't like options",
     true
   );
   _Tftp_Add_interaction_send_rrq(
     TFTP_FIRST_FD,
     tftpfs_file,
     TFTP_STD_PORT,
     tftpfs_ipv4_loopback,
     NO_BLOCK_SIZE_OPTION,
     NO_WINDOW_SIZE_OPTION,
     true
   );
   _Tftp_Add_interaction_recv_error(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     TFTP_ERROR_CODE_ILLEGAL,
     "Go away",
     true
   );
   _Tftp_Add_interaction_close( TFTP_FIRST_FD, 0 );
 
   bytes_read = read_tftp_file(
     create_tftpfs_path( tftpfs_ipv4_loopback, tftpfs_file ),
     TFTP_DEFAULT_BLOCK_SIZE / 2, /* Bytes read per call to read() */
     SIZE_MAX,
     &ctx->fd0
   );
   T_eq_int( errno, EINVAL );
   T_eq_int( bytes_read, 0 );
   T_no_more_interactions();
 }
 
 /*
  * Write a file to the server and the server responses with an ACK packet.
  * The file is half a data packet long.  No timeouts, packet loss, ...
  * Tests:
  *   * The client uses windowsize and blksize option in the WRQ.
  *   * The client uses the RFC1350 option values for the data transfer
  *     because the server responded with an ACK packet.
  *   * The whole package sequence behaves as if only RFC1350 was used.
  *   * The first data packet is half filled and signals the end of the
  *     transfer.
  */
 T_TEST_CASE_FIXTURE( write_file_ACK_instead_of_OACK, &fixture_default_options )
 {
   tftp_test_context *ctx = T_fixture_context();
   int bytes_written;
   size_t pos_in_file = 0;
   uint16_t block_num = 0;
 
   /* T_set_verbosity( T_VERBOSE ); */
   _Tftp_Add_interaction_socket( AF_INET, SOCK_DGRAM, 0, TFTP_FIRST_FD );
   _Tftp_Add_interaction_send_wrq(
     TFTP_FIRST_FD,
     tftpfs_file,
     TFTP_STD_PORT,
     tftpfs_ipv4_loopback,
     TFTP_DEFAULT_BLOCK_SIZE,
     TFTP_DEFAULT_WINDOW_SIZE,
     true
   );
   _Tftp_Add_interaction_recv_ack(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     block_num++,
     true
   );
   _Tftp_Add_interaction_send_data(
     TFTP_FIRST_FD,
     block_num,
     pos_in_file,
     TFTP_RFC1350_BLOCK_SIZE / 2,
     get_file_content,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     true
   );
   pos_in_file += TFTP_RFC1350_BLOCK_SIZE / 2;
   _Tftp_Add_interaction_recv_ack(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     block_num++,
     true
   );
   _Tftp_Add_interaction_close( TFTP_FIRST_FD, 0 );
 
   bytes_written = write_tftp_file(
     create_tftpfs_path( tftpfs_ipv4_loopback, tftpfs_file ),
     pos_in_file, /* Size of file */
     2 * TFTP_RFC1350_BLOCK_SIZE, /* Bytes written per call to write() */
     &ctx->fd0
   );
   T_eq_int( bytes_written, pos_in_file );
   T_no_more_interactions();
 }
 
 /*
  * Write a file and when the server responses with an ERROR to options
  * fallback to no options.
  * The file is half a data packet long.  No timeouts, packet loss, ...
  * Tests:
  *   * The client uses windowsize and blksize options in the first WRQ.
  *   * Upon reception of an ERROR from the server, the client re-tries
  *     opening a session using a WRQ without options.
  *   * The second WRQ is sent to the TFTP server port 69 and not to the
  *     port from which the first ERROR packet came from.
  *   * The server accepts the WRQ without options by sending an ACK packet.
  *   * The first data packet is half filled and signals the end of the transfer.
  */
 T_TEST_CASE_FIXTURE( write_file_fallback_to_no_options,
   &fixture_default_options )
 {
   tftp_test_context *ctx = T_fixture_context();
   int bytes_written;
   size_t pos_in_file = 0;
   uint16_t block_num = 0;
 
   /* T_set_verbosity( T_VERBOSE ); */
   _Tftp_Add_interaction_socket( AF_INET, SOCK_DGRAM, 0, TFTP_FIRST_FD );
   _Tftp_Add_interaction_send_wrq(
     TFTP_FIRST_FD,
     tftpfs_file,
     TFTP_STD_PORT,
     tftpfs_ipv4_loopback,
     TFTP_DEFAULT_BLOCK_SIZE,
     TFTP_DEFAULT_WINDOW_SIZE,
     true
   );
   _Tftp_Add_interaction_recv_error(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     TFTP_ERROR_CODE_ILLEGAL,
     "Don't like options",
     true
   );
   _Tftp_Add_interaction_send_wrq(
     TFTP_FIRST_FD,
     tftpfs_file,
     TFTP_STD_PORT,
     tftpfs_ipv4_loopback,
     NO_BLOCK_SIZE_OPTION,
     NO_WINDOW_SIZE_OPTION,
     true
   );
   _Tftp_Add_interaction_recv_ack(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     block_num++,
     true
   );
   _Tftp_Add_interaction_send_data(
     TFTP_FIRST_FD,
     block_num,
     pos_in_file,
     TFTP_RFC1350_BLOCK_SIZE / 2,
     get_file_content,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     true
   );
   pos_in_file += TFTP_RFC1350_BLOCK_SIZE / 2;
   _Tftp_Add_interaction_recv_ack(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     block_num++,
     true
   );
   _Tftp_Add_interaction_close( TFTP_FIRST_FD, 0 );
 
   bytes_written = write_tftp_file(
     create_tftpfs_path( tftpfs_ipv4_loopback, tftpfs_file ),
     pos_in_file, /* Size of file */
     2 * TFTP_RFC1350_BLOCK_SIZE, /* Bytes written per call to write() */
     &ctx->fd0
   );
   T_eq_int( bytes_written, pos_in_file );
   T_no_more_interactions();
 }
 
 /*
  * The server sends a malformed OACK: The final 0 byte is missing.
  */
 T_TEST_CASE_FIXTURE( OACK_without_null, &fixture_default_options )
 {
   tftp_test_context *ctx = T_fixture_context();
   int bytes_read;
   const char options[] = { 'b', 'l', 'k', 's', 'i', 'z', 'e', '\0', '1', '2' };
 
   /* T_set_verbosity( T_VERBOSE ); */
   _Tftp_Add_interaction_socket( AF_INET, SOCK_DGRAM, 0, TFTP_FIRST_FD );
   _Tftp_Add_interaction_send_rrq(
     TFTP_FIRST_FD,
     tftpfs_file,
     TFTP_STD_PORT,
     tftpfs_ipv4_loopback,
     TFTP_DEFAULT_BLOCK_SIZE,
     TFTP_DEFAULT_WINDOW_SIZE,
     true
   );
   _Tftp_Add_interaction_recv_oack(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     options,
     sizeof( options ),
     true
   );
   _Tftp_Add_interaction_send_error(
     TFTP_FIRST_FD,
     TFTP_ERROR_CODE_OPTION_NEGO,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     true
   );
   _Tftp_Add_interaction_close( TFTP_FIRST_FD, 0 );
 
   bytes_read = read_tftp_file(
     create_tftpfs_path( tftpfs_ipv4_loopback, tftpfs_file ),
     LARGE_BLOCK_SIZE, /* Bytes read per call to read() */
     SIZE_MAX,
     &ctx->fd0
   );
   T_eq_int( errno, EPROTO );
   T_eq_int( bytes_read, 0 );
   T_no_more_interactions();
 }
 
 /*
  * Server sends a malformed OACK packet: The value of the option is missing.
  */
 T_TEST_CASE_FIXTURE( OACK_without_option_value, &fixture_default_options )
 {
   tftp_test_context *ctx = T_fixture_context();
   int bytes_read;
   const char options[] = TFTP_OPTION_BLKSIZE;
 
   /* T_set_verbosity( T_VERBOSE ); */
   _Tftp_Add_interaction_socket( AF_INET, SOCK_DGRAM, 0, TFTP_FIRST_FD );
   _Tftp_Add_interaction_send_rrq(
     TFTP_FIRST_FD,
     tftpfs_file,
     TFTP_STD_PORT,
     tftpfs_ipv4_loopback,
     TFTP_DEFAULT_BLOCK_SIZE,
     TFTP_DEFAULT_WINDOW_SIZE,
     true
   );
   _Tftp_Add_interaction_recv_oack(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     options,
     sizeof( options ),
     true
   );
   _Tftp_Add_interaction_send_error(
     TFTP_FIRST_FD,
     TFTP_ERROR_CODE_OPTION_NEGO,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     true
   );
   _Tftp_Add_interaction_close( TFTP_FIRST_FD, 0 );
 
   bytes_read = read_tftp_file(
     create_tftpfs_path( tftpfs_ipv4_loopback, tftpfs_file ),
     LARGE_BLOCK_SIZE, /* Bytes read per call to read() */
     SIZE_MAX,
     &ctx->fd0
   );
   T_eq_int( errno, EPROTO );
   T_eq_int( bytes_read, 0 );
   T_no_more_interactions();
 }
 
 /*
  * Server sends a malformed OACK packet: The option is unknown.
  */
 T_TEST_CASE_FIXTURE( OACK_with_unknown_option, &fixture_default_options )
 {
   tftp_test_context *ctx = T_fixture_context();
   int bytes_read;
   const char options[] =
     "shoesize" "\0"
     RTEMS_XSTRING( TFTP_DEFAULT_BLOCK_SIZE );
 
   /* T_set_verbosity( T_VERBOSE ); */
   _Tftp_Add_interaction_socket( AF_INET, SOCK_DGRAM, 0, TFTP_FIRST_FD );
   _Tftp_Add_interaction_send_rrq(
     TFTP_FIRST_FD,
     tftpfs_file,
     TFTP_STD_PORT,
     tftpfs_ipv4_loopback,
     TFTP_DEFAULT_BLOCK_SIZE,
     TFTP_DEFAULT_WINDOW_SIZE,
     true
   );
   _Tftp_Add_interaction_recv_oack(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     options,
     sizeof( options ),
     true
   );
   _Tftp_Add_interaction_send_error(
     TFTP_FIRST_FD,
     TFTP_ERROR_CODE_OPTION_NEGO,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     true
   );
   _Tftp_Add_interaction_close( TFTP_FIRST_FD, 0 );
 
   bytes_read = read_tftp_file(
     create_tftpfs_path( tftpfs_ipv4_loopback, tftpfs_file ),
     LARGE_BLOCK_SIZE, /* Bytes read per call to read() */
     SIZE_MAX,
     &ctx->fd0
   );
   T_eq_int( errno, EPROTO );
   T_eq_int( bytes_read, 0 );
   T_no_more_interactions();
 }
 
 /*
  * Server sends a malformed OACK packet: The value of the option is
  * not a number.
  */
 T_TEST_CASE_FIXTURE( OACK_malformed_option_value, &fixture_default_options )
 {
   tftp_test_context *ctx = T_fixture_context();
   int bytes_read;
   const char options[] = TFTP_OPTION_BLKSIZE "\0" "abc";
 
   /* T_set_verbosity( T_VERBOSE ); */
   _Tftp_Add_interaction_socket( AF_INET, SOCK_DGRAM, 0, TFTP_FIRST_FD );
   _Tftp_Add_interaction_send_rrq(
     TFTP_FIRST_FD,
     tftpfs_file,
     TFTP_STD_PORT,
     tftpfs_ipv4_loopback,
     TFTP_DEFAULT_BLOCK_SIZE,
     TFTP_DEFAULT_WINDOW_SIZE,
     true
   );
   _Tftp_Add_interaction_recv_oack(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     options,
     sizeof( options ),
     true
   );
   _Tftp_Add_interaction_send_error(
     TFTP_FIRST_FD,
     TFTP_ERROR_CODE_OPTION_NEGO,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     true
   );
   _Tftp_Add_interaction_close( TFTP_FIRST_FD, 0 );
 
   bytes_read = read_tftp_file(
     create_tftpfs_path( tftpfs_ipv4_loopback, tftpfs_file ),
     LARGE_BLOCK_SIZE, /* Bytes read per call to read() */
     SIZE_MAX,
     &ctx->fd0
   );
   T_eq_int( errno, EPROTO );
   T_eq_int( bytes_read, 0 );
   T_no_more_interactions();
 }
 
 /*
  * Server sends a malformed OACK packet: The value of the option is empty.
  */
 T_TEST_CASE_FIXTURE( OACK_with_empty_option_value, &fixture_default_options )
 {
   tftp_test_context *ctx = T_fixture_context();
   int bytes_read;
   const char options[] = TFTP_OPTION_BLKSIZE "\0";
 
   /* T_set_verbosity( T_VERBOSE ); */
   _Tftp_Add_interaction_socket( AF_INET, SOCK_DGRAM, 0, TFTP_FIRST_FD );
   _Tftp_Add_interaction_send_rrq(
     TFTP_FIRST_FD,
     tftpfs_file,
     TFTP_STD_PORT,
     tftpfs_ipv4_loopback,
     TFTP_DEFAULT_BLOCK_SIZE,
     TFTP_DEFAULT_WINDOW_SIZE,
     true
   );
   _Tftp_Add_interaction_recv_oack(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     options,
     sizeof( options ),
     true
   );
   _Tftp_Add_interaction_send_error(
     TFTP_FIRST_FD,
     TFTP_ERROR_CODE_OPTION_NEGO,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     true
   );
   _Tftp_Add_interaction_close( TFTP_FIRST_FD, 0 );
 
   bytes_read = read_tftp_file(
     create_tftpfs_path( tftpfs_ipv4_loopback, tftpfs_file ),
     LARGE_BLOCK_SIZE, /* Bytes read per call to read() */
     SIZE_MAX,
     &ctx->fd0
   );
   T_eq_int( errno, EPROTO );
   T_eq_int( bytes_read, 0 );
   T_no_more_interactions();
 }
 
 /*
  * Server sends a malformed OACK packet: The option name is empty.
  */
 T_TEST_CASE_FIXTURE( OACK_with_empty_option_name, &fixture_default_options )
 {
   tftp_test_context *ctx = T_fixture_context();
   int bytes_read;
   const char options[] = "\0" RTEMS_XSTRING( TFTP_DEFAULT_BLOCK_SIZE );
 
   /* T_set_verbosity( T_VERBOSE ); */
   _Tftp_Add_interaction_socket( AF_INET, SOCK_DGRAM, 0, TFTP_FIRST_FD );
   _Tftp_Add_interaction_send_rrq(
     TFTP_FIRST_FD,
     tftpfs_file,
     TFTP_STD_PORT,
     tftpfs_ipv4_loopback,
     TFTP_DEFAULT_BLOCK_SIZE,
     TFTP_DEFAULT_WINDOW_SIZE,
     true
   );
   _Tftp_Add_interaction_recv_oack(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     options,
     sizeof( options ),
     true
   );
   _Tftp_Add_interaction_send_error(
     TFTP_FIRST_FD,
     TFTP_ERROR_CODE_OPTION_NEGO,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     true
   );
   _Tftp_Add_interaction_close( TFTP_FIRST_FD, 0 );
 
   bytes_read = read_tftp_file(
     create_tftpfs_path( tftpfs_ipv4_loopback, tftpfs_file ),
     LARGE_BLOCK_SIZE, /* Bytes read per call to read() */
     SIZE_MAX,
     &ctx->fd0
   );
   T_eq_int( errno, EPROTO );
   T_eq_int( bytes_read, 0 );
   T_no_more_interactions();
 }
 
 /*
  * Server sends a malformed OACK packet: The block size option value
  * is too small.
  */
 T_TEST_CASE_FIXTURE( OACK_blocksize_too_small, &fixture_default_options )
 {
   tftp_test_context *ctx = T_fixture_context();
   int bytes_read;
   const char options[] = TFTP_OPTION_BLKSIZE "\0" "7";
 
   /* T_set_verbosity( T_VERBOSE ); */
   _Tftp_Add_interaction_socket( AF_INET, SOCK_DGRAM, 0, TFTP_FIRST_FD );
   _Tftp_Add_interaction_send_rrq(
     TFTP_FIRST_FD,
     tftpfs_file,
     TFTP_STD_PORT,
     tftpfs_ipv4_loopback,
     TFTP_DEFAULT_BLOCK_SIZE,
     TFTP_DEFAULT_WINDOW_SIZE,
     true
   );
   _Tftp_Add_interaction_recv_oack(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     options,
     sizeof( options ),
     true
   );
   _Tftp_Add_interaction_send_error(
     TFTP_FIRST_FD,
     TFTP_ERROR_CODE_OPTION_NEGO,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     true
   );
   _Tftp_Add_interaction_close( TFTP_FIRST_FD, 0 );
 
   bytes_read = read_tftp_file(
     create_tftpfs_path( tftpfs_ipv4_loopback, tftpfs_file ),
     LARGE_BLOCK_SIZE, /* Bytes read per call to read() */
     SIZE_MAX,
     &ctx->fd0
   );
   T_eq_int( errno, EPROTO );
   T_eq_int( bytes_read, 0 );
   T_no_more_interactions();
 }
 
 /*
  * Server sends a malformed OACK packet: The block size option value
  * is too large.
  */
 T_TEST_CASE_FIXTURE( OACK_blocksize_too_large, &fixture_default_options )
 {
   tftp_test_context *ctx = T_fixture_context();
   int bytes_read;
   const char options[] = TFTP_OPTION_BLKSIZE "\0" "1457";
 
   /* T_set_verbosity( T_VERBOSE ); */
   _Tftp_Add_interaction_socket( AF_INET, SOCK_DGRAM, 0, TFTP_FIRST_FD );
   _Tftp_Add_interaction_send_rrq(
     TFTP_FIRST_FD,
     tftpfs_file,
     TFTP_STD_PORT,
     tftpfs_ipv4_loopback,
     TFTP_DEFAULT_BLOCK_SIZE,
     TFTP_DEFAULT_WINDOW_SIZE,
     true
   );
   _Tftp_Add_interaction_recv_oack(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     options,
     sizeof( options ),
     true
   );
   _Tftp_Add_interaction_send_error(
     TFTP_FIRST_FD,
     TFTP_ERROR_CODE_OPTION_NEGO,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     true
   );
   _Tftp_Add_interaction_close( TFTP_FIRST_FD, 0 );
 
   bytes_read = read_tftp_file(
     create_tftpfs_path( tftpfs_ipv4_loopback, tftpfs_file ),
     LARGE_BLOCK_SIZE, /* Bytes read per call to read() */
     SIZE_MAX,
     &ctx->fd0
   );
   T_eq_int( errno, EPROTO );
   T_eq_int( bytes_read, 0 );
   T_no_more_interactions();
 }
 
 /*
  * Server sends a malformed OACK packet: The windowsize option value
  * is too small.
  */
 T_TEST_CASE_FIXTURE( OACK_windowsize_too_small, &fixture_default_options )
 {
   tftp_test_context *ctx = T_fixture_context();
   int bytes_read;
   const char options[] = TFTP_OPTION_WINDOWSIZE "\0" "0";
 
   /* T_set_verbosity( T_VERBOSE ); */
   _Tftp_Add_interaction_socket( AF_INET, SOCK_DGRAM, 0, TFTP_FIRST_FD );
   _Tftp_Add_interaction_send_rrq(
     TFTP_FIRST_FD,
     tftpfs_file,
     TFTP_STD_PORT,
     tftpfs_ipv4_loopback,
     TFTP_DEFAULT_BLOCK_SIZE,
     TFTP_DEFAULT_WINDOW_SIZE,
     true
   );
   _Tftp_Add_interaction_recv_oack(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     options,
     sizeof( options ),
     true
   );
   _Tftp_Add_interaction_send_error(
     TFTP_FIRST_FD,
     TFTP_ERROR_CODE_OPTION_NEGO,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     true
   );
   _Tftp_Add_interaction_close( TFTP_FIRST_FD, 0 );
 
   bytes_read = read_tftp_file(
     create_tftpfs_path( tftpfs_ipv4_loopback, tftpfs_file ),
     LARGE_BLOCK_SIZE, /* Bytes read per call to read() */
     SIZE_MAX,
     &ctx->fd0
   );
   T_eq_int( errno, EPROTO );
   T_eq_int( bytes_read, 0 );
   T_no_more_interactions();
 }
 
 /*
  * Server sends a malformed OACK packet: The windowsize option is too large.
  */
 T_TEST_CASE_FIXTURE( OACK_windowsize_too_large, &fixture_default_options )
 {
   tftp_test_context *ctx = T_fixture_context();
   int bytes_read;
   const char options[] = TFTP_OPTION_WINDOWSIZE "\0" "9";
 
   /* T_set_verbosity( T_VERBOSE ); */
   _Tftp_Add_interaction_socket( AF_INET, SOCK_DGRAM, 0, TFTP_FIRST_FD );
   _Tftp_Add_interaction_send_rrq(
     TFTP_FIRST_FD,
     tftpfs_file,
     TFTP_STD_PORT,
     tftpfs_ipv4_loopback,
     TFTP_DEFAULT_BLOCK_SIZE,
     TFTP_DEFAULT_WINDOW_SIZE,
     true
   );
   _Tftp_Add_interaction_recv_oack(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     options,
     sizeof( options ),
     true
   );
   _Tftp_Add_interaction_send_error(
     TFTP_FIRST_FD,
     TFTP_ERROR_CODE_OPTION_NEGO,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     true
   );
   _Tftp_Add_interaction_close( TFTP_FIRST_FD, 0 );
 
   bytes_read = read_tftp_file(
     create_tftpfs_path( tftpfs_ipv4_loopback, tftpfs_file ),
     LARGE_BLOCK_SIZE, /* Bytes read per call to read() */
     SIZE_MAX,
     &ctx->fd0
   );
   T_eq_int( errno, EPROTO );
   T_eq_int( bytes_read, 0 );
   T_no_more_interactions();
 }
 
 /*
  * Server sends a malformed OACK packet: There is a known but surplus option.
  */
 T_TEST_CASE_FIXTURE( OACK_with_surplus_option, &fixture_large_blocksize )
 {
   tftp_test_context *ctx = T_fixture_context();
   int bytes_read;
   const char options[] =
     TFTP_OPTION_BLKSIZE "\0"
     RTEMS_XSTRING( LARGE_BLOCK_SIZE ) "\0"
     TFTP_OPTION_WINDOWSIZE "\0"
     "1";
 
   /* T_set_verbosity( T_VERBOSE ); */
   _Tftp_Add_interaction_socket( AF_INET, SOCK_DGRAM, 0, TFTP_FIRST_FD );
   _Tftp_Add_interaction_send_rrq(
     TFTP_FIRST_FD,
     tftpfs_file,
     TFTP_STD_PORT,
     tftpfs_ipv4_loopback,
     LARGE_BLOCK_SIZE,
     NO_WINDOW_SIZE_OPTION,
     true
   );
   _Tftp_Add_interaction_recv_oack(
     TFTP_FIRST_FD,
     FIRST_TIMEOUT_MILLISECONDS,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     options,
     sizeof( options ),
     true
   );
   _Tftp_Add_interaction_send_error(
     TFTP_FIRST_FD,
     TFTP_ERROR_CODE_OPTION_NEGO,
     SERV_PORT,
     tftpfs_ipv4_loopback,
     true
   );
   _Tftp_Add_interaction_close( TFTP_FIRST_FD, 0 );
 
   bytes_read = read_tftp_file(
     create_tftpfs_path( tftpfs_ipv4_loopback, tftpfs_file ),
     LARGE_BLOCK_SIZE, /* Bytes read per call to read() */
     SIZE_MAX,
     &ctx->fd0
   );
   T_eq_int( errno, EPROTO );
   T_eq_int( bytes_read, 0 );
   T_no_more_interactions();
 }
 
 const char rtems_test_name[] = "TFTPFS";
 
 static void Init( rtems_task_argument argument )
 {
   rtems_test_run( argument, TEST_STATE );
 }
 
 /*
  * RTEMS configuration for tftp
  */
 
 #define CONFIGURE_FILESYSTEM_TFTPFS
 #define CONFIGURE_MAXIMUM_FILE_DESCRIPTORS 4
 
 /*
  * Simple RTEMS configuration
  */
 
 #define CONFIGURE_APPLICATION_NEEDS_CLOCK_DRIVER
 #define CONFIGURE_APPLICATION_NEEDS_SIMPLE_CONSOLE_DRIVER
 
 #define CONFIGURE_MAXIMUM_TASKS 1
 
 #define CONFIGURE_RTEMS_INIT_TASKS_TABLE
 
 #define CONFIGURE_INIT_TASK_ATTRIBUTES RTEMS_FLOATING_POINT
 
 #define CONFIGURE_INIT
 
 #include <rtems/confdefs.h>