pcap_file_generator

pcap_file_generator

This library is designed to generate files and read PCAP format. Generation of UDP packets is also supported

Functions:

PCAPFILE * lpcap_create(char * file_path )

The function creates a file and returns either NULL on error or a pointer to PCAPFILE

int lpcap_write_data( PCAPFILE * f_pcp , ethernet_data_t * eth_data, uint32_t current_seconds, uint32_t current_u_seconds)

Function for filling a file created through lpcap_create, returns 0 on error. At the input she receives:

1. PCAPFILE * f_pcp - pointer to the newly created file
2. ethernet_data_t * eth_data - data frame
3. uint32_t current_seconds - time shift in seconds relative to the previous frame
4. uint32_t current_u_seconds - time shift in microseconds relative to the previous frame

void lpcap_close_file( PCAPFILE * f_pcp )

File closing function It receives as input:

1. PCAPFILE * f_pcp - pointer to open and written file

void build_udp_frame(eth_frame_t * eth_f, network_packet_frame_t * nwp);

The function of generating an ethernet-ip-udp data packet ethernet_data_t based on data from network_packet_frame_t It receives as input:

1. Pointer to an instance of the eth_frame_t eth_f structure (an instance must be created in advance)
2. network_packet_frame_t *nwp pointer to an instance of the structure with data for the Ethernet-ip-udp packet

PCAPFILE * lpcap_open(char * file_path );

File opening function. If the file does not contain signs of PCAP format, 0 is returned, as in other error situations

int lpcap_read_header(PCAPFILE * pfl , pcap_hdr_t * phdr);

Function to read a file header from a PCAPFILE descriptor * pfl of an already open file in pcap_hdr_t * phdr phdr must point to an existing memory area. Returns 0 on error

int lpcap_read_frame_record(PCAPFILE * pfl , pcaprec_hdr_and_data_t * phdr);

Function to read a file data frame from a PCAPFILE handle * pfl of an already open file in pcaprec_hdr_and_data_t * phdr phdr must point to an existing memory area. Returns 0 on error

int lpcap_setpos_frame_record(PCAPFILE * pfl , pcaprec_hdr_t *pcp_rec_hdr, long record_num);

Function for moving the position pointer to the frame number (i.e. record) record_num.

Example of use with simple packet generation

  int i=0;
  const int  PKTS_COUNT = 212000;
  int PKTS_LEN =  540;
  static ethernet_data_t  eda;
  eda.len = PKTS_LEN;

  PCAPFILE * pfl = lpcap_create("./pcaplibtestfile.pcap");
  for( i=0;i< PKTS_COUNT;i++ )
  {
    /* TODO:  fill data   memcpy(eda.data , YOUR_DATA_BUF,SIZE_YOUR_DATA_BUF  );
       eda.len = SIZE_YOUR_DATA_BUF;
    */
   lpcap_write_data( pfl , &eda , i, 0 );
  }
  lpcap_close_file( pfl );

Example with generating UDP packets

 #include "pcap_file_generator.h"
#include "ethernet.h"
.......
  int i=0;
  const int  PKTS_COUNT = 2000100;
  const int udp_data_sz = 1440;// udp data size
  ethernet_data_t eda;
  eda.len = udp_data_sz +(sizeof(eth_frame_t)+sizeof(ip_packet_t))+8;//34 -  headers len

  uint8_t eth_data[eda.len];
  eth_frame_t * eth_f = (eth_frame_t *) eth_data;
  network_packet_frame_t npf;
  uint8_t  m_addr[] = {0xef,0xab,0x03, 0xdc,0xee,0x11};
  memcpy(npf.dst_mac ,m_addr , sizeof(m_addr));
//change mac
  m_addr[4] = 0x44;
  m_addr[5] = 0x88;

  memcpy(npf.src_mac ,m_addr , sizeof(m_addr));
  npf.src_port = 4567;
  npf.dst_port = 4568;
  strcpy(npf.src_ip, "192.168.23.100");
  strcpy(npf.dst_ip, "192.168.22.105");
  uint8_t tdata[ udp_data_sz ];
  npf.data = tdata;
  npf.data_len = sizeof(tdata);
  build_udp_frame(eth_f , &npf ); // convert network_packet_frame_t to  eth_frame_t
  eda.data = (void *) eth_f;

  PCAPFILE * pfl = lpcap_create("./pcaplibtestfile.pcap");
  for( i=0;i< PKTS_COUNT;i++ )
  {
   lpcap_write_data( pfl , &eda , i, 0 );
  }
  lpcap_close_file( pfl );

Example of reading packages from a file

 PCAPFILE  * pfr = lpcap_open("./pcaplibtestfile.pcap");
  pcap_hdr_t   phdr;
  if( lpcap_read_header( pfr, &phdr ))
  {
    int rese_rec_read = 0 ;
    pcaprec_hdr_and_data_t  p_rec_data;
    do{   
       rese_rec_read = lpcap_read_frame_record( pfr , &p_rec_data);
    }while(rese_rec_read>0);