readcapfile_example.c Source File

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42 

43 /**

44  *

45  * @example net/readcapfile/readcapfile_example.c

46  *

47  * @section readcapfile_example_description Description

48  *

49  * This source file is an example of how to read a capture file using NTAPI.

50  *

51  * The NT_NetFile...() functions does not require NTservice to be running.

52  *

53  * The following NTAPI functions are used:

54  * - @ref NT_Init()

55  * - @ref NT_NetFileOpen()

56  * - @ref NT_NetFileGet()

57  * - @ref NT_NET_GET_PKT_WIRE_LENGTH()

58  * - @ref NT_NetFileRelease()

59  * - @ref NT_NetFileClose()

60  * - @ref NT_ExplainError()

61  *

62  * @section readcapfile_example_prerequisites Prerequisites

63  *

64  * - Capture file, that has been captured with the @ref

65  * net/capture/capture_example.c "net/capture/capture_example.c" example.

66  *

67  * - The capture filename should be given as first argument to this example.

68  *

69  * @section readcapfile_example_flow Program flow

70  * @{

71  * The following is required to perform replay of a captured file

72  *

73  * - \#include/nt.h - Applications/Tools only need to include @ref nt.h

74  * to obtain prototypes, macros etc. from NTAPI.

75  * - @ref NT_Init(@ref NTAPI_VERSION) - Initialize the NTAPI

76  * library. @ref NTAPI_VERSION is a define that describes the version

77  * of the API described in the header files included by @ref

78  * nt.h. NT_Init() will ask the NTAPI library to convert return data

79  * to the @ref NTAPI_VERSION if possible. This will ensure that

80  * applications can run on NTAPI libraries of newer versions.

81  * - @ref NT_NetFileOpen() - Open the captured file and assign it to a stream.

82  * - @ref NT_NetFileGet() - Get a segment from the file. This call will

83  * return @ref NT_SUCCESS upon return of a segment and

84  * @ref NT_STATUS_END_OF_FILE when there is no more segments

85  * avaialble. The latter will cause the example to exit.

86  * - @ref NT_NetFileRelease() - Release the segment from the file stream.

87  * - @ref NT_NetFileClose() - Close the file stream when no more segments can be found.

88  *

89  *<hr>

90  *

91  * @section readcapfile_example_code Code

92  * @}

93  *

94  */

95 

96 // Include this in order to access the Napatech API

97 #include <nt.h>

98 

99 #include <argparse.h>

100 

101 static const char *usageText[] = {

102  "USAGE: readcapfile_example <nt3gd_capture_filename>\n"

103  "Commands:\n",

104  NULL};

105 

106 /**

107  * Table of valid options.

108  */

109 struct argparse_option arg_options[] = {

110  OPT_HELP(),

111  OPT_END(),

112 };

113 

114 

115 int main(int argc, const char** argv)

116 {

117  int status; // Status variable

118  char errorBuffer[NT_ERRBUF_SIZE]; // Error buffer

119  int numPackets = 0; // The number of packets replayed

120  int numBytes = 0; // The number of bytes replayed

121  int pktLen = 0; // packet lenght

122  int option;

123  const char* ntcap_filename = NULL;

124  NtNetStreamFile_t hNetFile; // Handle to the File stream

125  NtNetBuf_t hNetBufFile; // Net buffer container. Used to return segments from the file stream

126  struct argparse argparse;

127 

128  argparse_init(&argparse, arg_options, usageText, 0);

129  option = argparse_parse(&argparse, argc, argv);

130 

131  if ((option >= 1) && (argv[0] != NULL)) {

132  ntcap_filename = argv[0];

133  } else {

134  argparse_usage(&argparse);

135  exit(0);

136  }

137 

138  // Initialize the NTAPI library and thereby check if NTAPI_VERSION can be used together with this library

139  if ((status = NT_Init(NTAPI_VERSION)) != NT_SUCCESS) {

140  if ( status == NT_ERROR_NT_SERVICE_NOT_STARTED) {

141  printf("NOTE: NT serivice is not started.\n");

142  } else {

143  // Get the status code as text

144  NT_ExplainError(status, errorBuffer, sizeof(errorBuffer));

145  fprintf(stderr, "NT_Init() failed: %s\n", errorBuffer);

146  return -1;

147  }

148  }

149 

150  // Open the capture file to replay (captured with the capture example)

151  if ((status = NT_NetFileOpen(&hNetFile, "FileStream", NT_NET_INTERFACE_PACKET, ntcap_filename)) != NT_SUCCESS) {

152  // Get the status code as text

153  NT_ExplainError(status, errorBuffer, sizeof(errorBuffer));

154  fprintf(stderr, "NT_NetFileOpen() failed: %s\n", errorBuffer);

155  return -1;

156  }

157 

158  // Get packets from the file - update counters

159  while (1) {

160  // Get the packet

161  if ((status = NT_NetFileGet(hNetFile, &hNetBufFile)) != NT_SUCCESS) {

162  if (status == NT_STATUS_END_OF_FILE) {

163  // The file has no more data

164  break;

165  }

166  // Get the status code as text

167  NT_ExplainError(status, errorBuffer, sizeof(errorBuffer));

168  fprintf(stderr, "NT_NetFileGet() failed: %s\n", errorBuffer);

169  return -1;

170  }

171  numPackets++,

172  pktLen = NT_NET_GET_PKT_WIRE_LENGTH((hNetBufFile));

173  numBytes += pktLen;

174  printf("Fetched packet: #%d: packet length: %d bytes - total capture length: %d bytes\n", numPackets, pktLen, numBytes);

175 

176  // Release the file packet

177  if ((status = NT_NetFileRelease(hNetFile, hNetBufFile)) != NT_SUCCESS) {

178  // Get the status code as text

179  NT_ExplainError(status, errorBuffer, sizeof(errorBuffer));

180  fprintf(stderr, "NT_NetFileRelease() failed: %s\n", errorBuffer);

181  return -1;

182  }

183  }

184 

185  // Close the file stream

186  NT_NetFileClose(hNetFile);

187 

188  printf("Done: %d packets %d bytes has been read\n", numPackets, numBytes);

189  return 0;

190 }

191 

192 //

193 // EOF

194 //