pcaptest

#include <pcap.h>
#include <netinet/in.h>
#include <sys/socket.h>
#include <pthread.h>
#include <unistd.h>

#include "nbns.h"

char running = 1;
pcap_t *handle;

void *sender(void *arg) {
  int sockfd;
  struct sockaddr_in addr;

  sockfd = socket(AF_INET, SOCK_DGRAM, 0);

  memset(&addr, 0, sizeof(addr));

  addr.sin_family = AF_INET;
  addr.sin_port = htons(137);
  addr.sin_addr.s_addr = htonl(0xC0A80001); // 192.168.0.1

  connect(sockfd, (struct sockaddr *) &addr, sizeof(addr));

  while(running) {
    write(sockfd, nbns_nbstat_request, NBNS_NBSTATREQ_LEN);
    usleep(10);
  }

  sendto(sockfd, nbns_nbstat_request, NBNS_NBSTATREQ_LEN, 0, (struct sockaddr *) &addr, sizeof(addr));

  return NULL;
}

void stop(int signal) {
  //pcap_breakloop(handle);
  running = 0;
}

void pcap_callback(u_char *user, const struct pcap_pkthdr *h, const u_char *bytes) {
  if(!running) {
    pcap_breakloop(handle);
  }
}

void *receiver(void *arg) {
  int ret;
  struct bpf_program filter;
  char err_buff[PCAP_ERRBUF_SIZE];

  handle = pcap_open_live((char *) arg, 0x40000, 0, 1000, err_buff);

  if(!handle) {
    fprintf(stderr, "pcap_open_live: %s", err_buff);
    running = 0;
    return NULL;
  }

  if(pcap_compile(handle, &filter, "udp and port 137", 1, 0xffffff00)) {
    fprintf( stderr, "pcap_compile: %s", pcap_geterr(handle));
    pcap_close(handle);
    running = 0;
    return NULL;
  }

  if(pcap_setfilter(handle, &filter)) {
    fprintf( stderr, "pcap_setfilter: %s", pcap_geterr(handle));
    pcap_close(handle);
    running = 0;
    return NULL;
  }

  ret = pcap_loop(handle, -1, pcap_callback, NULL);

  return (void *) ret;
}

int main(int argc, char **argv) {
  pthread_t tid;
  int ret;

  if(argc != 2) return 1;

  if(signal(SIGINT, stop) == SIG_ERR) return 2;

  if(pthread_create(&tid, NULL, receiver, (void *) argv[1])) {
    pcap_close(handle);
    return 6;
  }

  sender(NULL);

  running=0;

  pthread_join(tid, (void **) &ret);

  if(ret == -1) {
    fprintf(stderr, "pcap_loop: %s\n", pcap_geterr(handle));
    return 7;
  }

  return 0;
}