1 #include <stdio.h>
2 #include <pcap.h>
3 #include <time.h>
4 #include <netinet/in.h>
5 #include <arpa/inet.h>
6 #include <errno.h>
7 #include <string.h>
8 #include <iostream>
9
10 using namespace std;
11
12 //IP层数据包格式
13 typedef struct
14 {
15 int header_len:4;
16 int version:4;
17 u_char tos:8;
18 int total_len:16;
19 int ident:16;
20 int flags:16;
21 u_char ttl:8;
22 u_char proto:8;
23 int checksum:16;
24 u_char sourceIP[4];
25 u_char destIP[4];
26 }IPHEADER;
27
28 void callback(u_char* user,const struct pcap_pkthdr* header,const u_char* pkt_data);
29
30 int main(int argc, char **argv)
31 {
32 char *device = NULL;
33 char errbuf[1024];
34 pcap_t *pcap;
35 int link_data;
36
37 if((device = pcap_lookupdev(errbuf)) == NULL)
38 {
39 perror(errbuf);
40 return 1;
41 }
42
43 pcap = pcap_open_live(device, 65535, 1, 0, errbuf);
44 if(pcap == NULL)
45 {
46 perror(errbuf);
47 return 1;
48 }
49
50 if((link_data = pcap_datalink(pcap)) == -1)
51 {
52 fprintf(stderr,"pcap_link_data: %s\n",pcap_geterr(pcap));
53 return 1;
54 }
55
56 cout<<"开始抓包"<<endl;
57 pcap_loop(pcap, -1, callback, NULL);
58
59 return 0;
60 }
61
62 void callback(u_char* user,const struct pcap_pkthdr* header,const u_char* pkt_data)
63 {
64 cout<<"\t\t抓到一个包"<<endl;
65 cout<<"-------------------------------------------------"<<endl;
66 //解析数据包IP头部
67 if(header->len>=14){
68 IPHEADER *ip_header=(IPHEADER*)(pkt_data+14);
69 //解析协议类型
70 cout<<"|版本 "<<ip_header->version<<"|首部长度"<<ip_header->header_len*4<<"字节|\t\t|"
71 "总长度"<<ip_header->total_len<<"字节|"<<endl;
72 cout<<"-------------------------------------------------"<<endl;
73 cout<<"|\t\t\t|\t|\t\t|"<<endl;
74 cout<<"-------------------------------------------------"<<endl;
75 cout<<"|ttl "<<int(ip_header->ttl)<<"\t|协议 ";
76 switch(ip_header->proto)
77 {
78 case 1:
79 cout<<"ICMP";
80 break;
81 case 2:
82 cout<<"IGMP";
83 break;
84 case 6:
85 cout<<"TCP ";
86 break;
87 case 17:
88 cout<<"UDP ";
89 break;
90 case 41:
91 cout<<"IPv6";
92 break;
93 default:
94 cout<<"IPv4";
95 }
96 cout<<"\t|首部校验和 "<<ip_header->checksum<<"\t|"<<endl;
97 cout<<"-------------------------------------------------"<<endl;
98 printf("|\t\t源地址 : %d.%d.%d.%d\t\t|\n",\
99 ip_header->sourceIP[0],ip_header->sourceIP[1],ip_header->sourceIP[2],ip_header->sourceIP[3]);
100 cout<<"-------------------------------------------------"<<endl;
101 printf("|\t\t目的地址 : %d.%d.%d.%d\t\t|\n",\
102 ip_header->destIP[0],ip_header->destIP[1],ip_header->destIP[2],ip_header->destIP[3]);
103 cout<<"-------------------------------------------------"<<endl;
104 cout<<endl;
105 }
106 }
