Winpcap笔记4之不用回调函数捕获数据包

  1 //不用回掉函数捕获数据包
  2 #include "pcap.h"
  3 
  4 
  5 int main()
  6 {
  7     pcap_if_t *alldevs;
  8     pcap_if_t *d;
  9     int inum;
 10     int i = 0;
 11     pcap_t *adhandle;
 12     int res;
 13     char errbuf[PCAP_ERRBUF_SIZE];
 14     struct tm *ltime;
 15     char timestr[16];
 16     struct pcap_pkthdr *header;
 17     const u_char *pkt_data;
 18     time_t local_tv_sec;
 19 
 20 
 21     /* 获取本机设备列表 */
 22     if (pcap_findalldevs_ex(PCAP_SRC_IF_STRING, NULL, &alldevs, errbuf) == -1)
 23     {
 24         fprintf(stderr, "Error in pcap_findalldevs: %s\n", errbuf);
 25         exit(1);
 26     }
 27 
 28     /* 打印列表 */
 29     for (d = alldevs; d; d = d->next)
 30     {
 31         printf("%d. %s", ++i, d->name);
 32         if (d->description)
 33             printf(" (%s)\n", d->description);
 34         else
 35             printf(" (No description available)\n");
 36     }
 37 
 38     if (i == 0)
 39     {
 40         printf("\nNo interfaces found! Make sure WinPcap is installed.\n");
 41         return -1;
 42     }
 43 
 44     printf("Enter the interface number (1-%d):", i);
 45     scanf("%d", &inum);
 46 
 47     if (inum < 1 || inum > i)
 48     {
 49         printf("\nInterface number out of range.\n");
 50         /* 释放设备列表 */
 51         pcap_freealldevs(alldevs);
 52         return -1;
 53     }
 54 
 55     /* 跳转到已选中的适配器 */
 56     for (d = alldevs, i = 0; i < inum - 1; d = d->next, i++);
 57 
 58     /* 打开设备 */
 59     if ((adhandle = pcap_open(d->name,          // 设备名
 60         65536,            // 要捕捉的数据包的部分 
 61         // 65535保证能捕获到不同数据链路层上的每个数据包的全部内容
 62         PCAP_OPENFLAG_PROMISCUOUS,    // 混杂模式
 63         1000,             // 读取超时时间
 64         NULL,             // 远程机器验证
 65         errbuf            // 错误缓冲池
 66         )) == NULL)
 67     {
 68         fprintf(stderr, "\nUnable to open the adapter. %s is not supported by WinPcap\n", d->name);
 69         /* 释放设列表 */
 70         pcap_freealldevs(alldevs);
 71         return -1;
 72     }
 73 
 74     printf("\nlistening on %s...\n", d->description);
 75 
 76     /* 释放设备列表 */
 77     pcap_freealldevs(alldevs);
 78 
 79     /* 获取数据包 */
 80     while ((res = pcap_next_ex(adhandle, &header, &pkt_data)) >= 0){
 81 
 82         if (res == 0)
 83             /* 超时时间到 */
 84             continue;
 85 
 86         /* 将时间戳转换成可识别的格式 */
 87         local_tv_sec = header->ts.tv_sec;
 88         ltime = localtime(&local_tv_sec);
 89         strftime(timestr, sizeof timestr, "%H:%M:%S", ltime);
 90 
 91         printf("%s,%.6d len:%d\n", timestr, header->ts.tv_usec, header->len);
 92     }
 93 
 94     if (res == -1){
 95         printf("Error reading the packets: %s\n", pcap_geterr(adhandle));
 96         return -1;
 97     }
 98 
 99     return 0;
100 }