超级简单的使用lipcap库实现采集信令程序

 1

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>
#include <pcap.h>
#include <signal.h>
#include <getopt.h>

int main(int argc, char *argv[])
{

    int c;
    char *device = NULL;
    char *fname = NULL;
    char errbuf[PCAP_ERRBUF_SIZE];
    pcap_t *p = NULL;


    while ( (c = getopt(argc, argv, "di:")) != -1)
    {
        switch (c)
        {
            case 'd':
                {
                    pcap_if_t *alldevsp = NULL;
                    if (pcap_findalldevs(&alldevsp, errbuf) == -1)
                    {
                        fprintf(stderr, "\t #### failed to list the device, err msg: %s\n", strerror(errno));
                        exit(-1);
                    }
                    pcap_if_t *devsp = alldevsp;
                    fprintf(stderr, "List the device as follows:\n");
                    for (int i = 0; devsp; ++i, devsp = devsp->next)
                    {
                        fprintf(stderr, "\t (%d) %s\n", i, devsp->name? devsp->name:"(NULL)");
                    }
                    pcap_freealldevs(alldevsp);
                    exit(0);
                }
                break;

            case 'i':
                {
                        pcap_if_t *alldevsp = NULL;
                        char *endptr;
                    int device_index = strtol(optarg, &endptr, 10);
                    if (endptr[0] != '\0')
                    {
                        device = optarg;
                    }
                    else
                    {
                        if (pcap_findalldevs(&alldevsp, errbuf) == -1)
                        {
                            fprintf(stderr, "\t #### failed to list the device, err msg: %s\n", strerror(errno));
                            exit(1);
                        }
                        pcap_if_t *devsp = alldevsp;
                        for (; device_index > 0 && devsp; devsp = devsp->next, --device_index);
                        if (devsp) device = devsp->name;
                    }
                    if (device)
                    {
                        fprintf(stderr, "device name: %s\n", device);
                        p = pcap_open_live(device, 1600, 1, -1, errbuf);
                        if (p == NULL)
                        {
                            fprintf(stderr, "\t #### failed to open device (%s), err msg:%s\n", device, strerror(errno));
                            exit(1);
                        }
                    }
                    pcap_freealldevs(alldevsp);
                }
                break;
        }
    }

    if (argc != optind + 1)
    {
        fprintf(stderr, "You must specifies the file name to save packets\n");
        exit(-1);
    }
    fname = argv[optind];

    pcap_dumper_t *fp = pcap_dump_open(p, fname);
    if (fp == NULL)
    {
        fprintf(stderr, "\t Failed to open savefile name, err msg: %s\n", strerror(errno));
        exit(-1);
    }

    pcap_loop(p, -1, pcap_dump, (char*)fp);
    pcap_dump_close(fp);

    exit(0);
}