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| /*************************************************************************
> File Name : pcap_example.c
> Author : TL Song
> EMail : songtianlun@frytea.com
> Created Time : Thu Feb 18 18:57:20 2021
************************************************************************/
int main()
{
char err_buf[PCAP_ERRBUF_SIZE];
struct bpf_program fp_recv; /* The compiled filter expression */
char filter_recv[] = RECV_FILTER; /* The filter expression (filter 53 port)*/
pcap_t *handle_recv;
pcap_t *handle_recv_send;
bpf_u_int32 mask_recv; /* The netmask of our sniffing device */
bpf_u_int32 net_recv; /* The IP of our sniffing device */
u_char *pkt_data = NULL;
int rst;
struct pcap_pkthdr header;
struct pcap_pkthdr *p_header = &header;
printf("Recv Device: %s\n", RECV_DEVICE);
/*Step1, Open the session in promiscuous mode*/
handle_recv = pcap_open_live(RECV_DEVICE, BUFSIZ, 1, 1, err_buf);
if (handle_recv == NULL) {
fprintf(stderr, "Couldn't open device %s: %s\n", RECV_DEVICE, err_buf);
return 0;
}
handle_recv_send = pcap_open_live(RECV_DEVICE_SEND, BUFSIZ, 1, 1, err_buf);
if (handle_recv_send == NULL) {
printf("Couldn't open device %s: %s\n", RECV_DEVICE_SEND, err_buf);
return 0;
}
/*Step2, get network mask*/
if (pcap_lookupnet(RECV_DEVICE, &net_recv, &mask_recv, err_buf) == -1) {
fprintf(stderr, "Can't get netmask for device %s\n", RECV_DEVICE);
net_recv = 0;
mask_recv = 0;
}
/* Step3, Compile and apply the filter */
if (pcap_compile(handle_recv, &fp_recv, filter_recv, 0, net_recv) == -1) {
fprintf(stderr, "Couldn't parse filter %s: %s\n", filter_recv, pcap_geterr(handle_recv));
return 0;
}
if (pcap_setfilter(handle_recv, &fp_recv) == -1) {
fprintf(stderr, "Couldn't install filter %s: %s\n", filter_recv, pcap_geterr(handle_recv));
return 0;
}
/* Step4, get frame. */
while(1){
pkt_data = (unsigned char * )pcap_next(handle_recv, p_header);
rst = pcap_sendpacket(handle_recv_send, pkt_data, p_header->caplen);
printf("Send to %s ret : %d\n", RECV_DEVICE_SEND, rst);
}
/* Step5, cleanup */
pcap_freecode(&fp_recv);
pcap_close(handle_recv);
pcap_close(handle_recv_send);
dPrint("Capture complete.");
return 0;
}
|
