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linux下c语言抓包库libpcap
小編覺得挺不錯的,現在分享給大家,幫大家做個參考.
安裝命令：sudo apt-get install libpcap-dev
由于自己還沒仔細研究過，暫時也只是想在這里留個記錄，方便以后需要時使用。下面是百度百科里的例子。
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#include?<pcap.h>??#include?<stdlib.h>??#include?<stdio.h>????int?main(int?argc,?char?*argv[])??{??????????pcap_if_t?*alldevs;??????????pcap_if_t?*device;??????????char?errbuf[PCAP_ERRBUF_SIZE];????????????if(pcap_findalldevs(&alldevs,?errbuf)?==?-1)??????????{??????????????????fprintf(stderr,?"Error?in?pcap_findalldevs:?%s\n",?errbuf);??????????????????exit(EXIT_FAILURE);??????????}??????????device?=?alldevs;??????????for(;?device?!=?NULL;?device?=?device->next)??????????{??????????????????printf("Device?name:?%s\n",?device->name);??????????????????printf("Description:?%s\n",?device->description);??????????}????????????????????pcap_freealldevs(alldevs);??????????return?0;??}??~????????????
gcc pcap.c -o pcap -lpcap
sudo ./pcap ? //記住一定要root權限，因為涉及了訪問底層硬件了。
下面是抓包并以二進制方式打印的，對于調試網絡包可能會經常使用到。
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#include?<pcap.h>??#include?<time.h>??#include?<stdlib.h>??#include?<stdio.h>????void?getPacket(u_char?*?arg,?const?struct?pcap_pkthdr?*?pkthdr,?const?u_char?*?packet)??{??????????int?*?id?=?(int?*)arg;????????????printf("id:?%d\n",?++(*id));??????????printf("Packet?length:?%d\n",?pkthdr->len);??????????printf("Number?of?bytes:?%d\n",?pkthdr->caplen);??????????printf("Recieved?time:?%s",?ctime((const?time_t?*)&pkthdr->ts.tv_sec));?????????????int?i;??????????for(i=0;?i<pkthdr->len;?++i)??????????{??????????????????printf("?%02x",?packet[i]);??????????????????if(?(i?+?1)?%?16?==?0?)??????????????????{??????????????????????????printf("\n");??????????????????}??????????}????????????printf("\n\n");??}????int?main()??{??????????char?errBuf[PCAP_ERRBUF_SIZE],?*?devStr;??????????????????????devStr?=?pcap_lookupdev(errBuf);????????????if(devStr)??????????{??????????????????printf("success:?device:?%s\n",?devStr);??????????}??????????else??????????{??????????????????printf("error:?%s\n",?errBuf);??????????????????exit(1);??????????}??????????????????????pcap_t?*?device?=?pcap_open_live(devStr,?65535,?1,?0,?errBuf);????????????if(!device)??????????{??????????????????printf("error:?pcap_open_live():?%s\n",?errBuf);??????????????????exit(1);??????????}??????????????????????int?id?=?0;??????????pcap_loop(device,?-1,?getPacket,?(u_char*)&id);????????????pcap_close(device);????????????return?0;??}??
下面是抓取數據包并解析網絡包，解析為物理層、網絡層等。
[cpp]?view plaincopy
#include?<pcap.h>??#include?<stdio.h>??#include?<netinet/ip.h>??#include?<netinet/if_ether.h>??#include?<netinet/tcp.h>????void?tcp_packet_callback(unsigned?char?*argument,const?struct?pcap_pkthdr*?pcap_header,const?unsigned?char?*packet_content)?{??????????struct?tcphdr?*tcpptr=(struct?tcphdr?*)(packet_content+14+20);??????????????????printf("----tcp?protocol-----\n");??????????????????printf("source?port:%d\n",ntohs(tcpptr->source));??????????????????printf("dest?port:%d\n",ntohs(tcpptr->dest));????????????????????printf("sequence?number:%u\n",ntohl(tcpptr->seq));??????????????????printf("acknowledgement?number:%u\n",ntohl(tcpptr->ack_seq));??????????????????printf("header?length:%d\n",tcpptr->doff*4);??????????????????printf("check?sum:%d\n",ntohs(tcpptr->check));??????????????????printf("window?size:%d\n",ntohs(tcpptr->window));??????????????????printf("urgent?pointer:%d\n",ntohs(tcpptr->urg_ptr));??}????void?ip_packet_callback(unsigned?char?*argument,const?struct?pcap_pkthdr*?pcap_header,const?unsigned?char?*packet_content)?{??????????struct?in_addr?s,d;??????????struct?iphdr?*ipptr;??????????ipptr=(struct?iphdr?*)(packet_content+14);????????????????????printf("-----IP?Protocol?(network?layer)-----\n");??????????????????printf("version:%d\n",ipptr->version);??????????????????printf("header?length:%d\n",ipptr->ihl*4);??????????????????printf("tos:%d\n",ipptr->tos);??????????????????printf("total?length:%d\n",ntohs(ipptr->tot_len));??????????????????printf("identification:%d\n",ntohs(ipptr->id));??????????????????printf("offset:%d\n",ntohs((ipptr->frag_off&0x1fff)*8));??????????????????printf("TTL:%d\n",ipptr->ttl);??????????????????printf("checksum:%d\n",ntohs(ipptr->check));??????????????????printf("protocol:%d\n",ipptr->protocol);??????????s.s_addr=ipptr->saddr;??????????d.s_addr=ipptr->daddr;??????????????????printf("source?address:%s\n",inet_ntoa(s));??????????????????printf("destination?address:%s\n",inet_ntoa(d));????????????switch(ipptr->protocol)?{??????????????????case?6:??????????????????????????????????????????????????printf("tcp?protocol\n");??????????????????????????tcp_packet_callback(argument,pcap_header,packet_content);??????????????????????????break;??????????????????case?1:??????????????????????????????????????????????????printf("icmp?protocol\n");??????????????????????????break;??????????????????case?17:??????????????????????????????????????????????????printf("udp?protocol\n");??????????????????????????break;??????????????????default:??????????????????????????break;??????????}????}????void?arp_packet_callback(unsigned?char?*argument,const?struct?pcap_pkthdr*?pcap_header,const?unsigned?char?*packet_content)?{??????????????????printf("------ARP?Protocol-------\n");??}????void?ethernet_packet_callback(unsigned?char?*argument,const?struct?pcap_pkthdr*?pcap_header,const?unsigned?char?*packet_content)?{??????????struct?ethhdr?*ethptr;??????????struct?iphdr?*ipptr;??????????unsigned?char?*mac;??????????printf("--------------------------context----------\n");????????????????????ethptr=(struct?ethhdr?*)packet_content;??????????????????printf("\n----ethernet?protocol(phydical?layer)-----\n");??????????????????printf("MAC?source?Address:\n");??????????mac=ethptr->h_source;??????????????????printf("%02x:%02x:%02x:%02x:%02x:%02x\n",*mac,*(mac+1),*(mac+2),*(mac+3),*(mac+4),*(mac+5));??????????????????printf("MAC?destination?Address:\n");??????????mac=ethptr->h_dest;??????????????????printf("%02x:%02x:%02x:%02x:%02x:%02x\n",*mac,*(mac+1),*(mac+2),*(mac+3),*(mac+4),*(mac+5));??????????????????printf("protocol:%04x\n",ntohs(ethptr->h_proto));????????????switch(ntohs(ethptr->h_proto))?{??????????????????case?0x0800:??????????????????????????????????????????????????printf("this?is?a?IP?protocol\n");??????????????????????????ip_packet_callback(argument,pcap_header,packet_content);??????????????????????????break;??????????????????case?0x0806:??????????????????????????????????????????????????printf("this?is?a?ARP?protocol\n");??????????????????????????arp_packet_callback(argument,pcap_header,packet_content);??????????????????????????break;??????????????????case?0x8035:??????????????????????????????????????????????????printf("this?is?a?RARP?protocol\n");??????????????????????????break;??????????????????default:??????????????????????????break;????????????}??}????int?main(){??????????pcap_t?*pt;??????????char?*dev;??????????char?errbuf[128];??????????struct?bpf_program?fp;??????????bpf_u_int32?maskp,netp;??????????int?ret,i=0,inum;??????????int?pcap_time_out=5;??????????char?filter[128];??????????unsigned?char?*packet;??????????struct?pcap_pkthdr?hdr;??????????pcap_if_t?*alldevs,*d;????????????if(pcap_findalldevs(&alldevs,errbuf)==-1)?{??????????????????????????????????fprintf(stderr,"find?interface?failed!\n");??????????????????return;??????????}??????????for(d=alldevs;d;d=d->next){??????????????????????????????????printf("%d.?%s\n",++i,d->name);??????????????????if(d->description)????????????????????????????????????????????printf("(%s)\n",d->description);??????????????????else????????????????????????????????????????????printf("(no?description?available)\n");??????????}????????????if(i==1)????????????????dev=alldevs->name;??????????else?{??????????????????printf("input?a?interface:(1-%d)",i);??????????????????scanf("%d",&inum);??????????????????if(inum<1||inum>i)?{??????????????????????????????????????????????????printf("interface?number?out?of?range\n");??????????????????????????return;??????????????????}????????????????????for(d=alldevs,i=1;i<inum;d=d->next,i++);??????????????????dev=d->name;??????????}????????????????????????????????????printf("dev:%s\n",dev);??????????ret=pcap_lookupnet(dev,&netp,&maskp,errbuf);??????????if(ret==-1){??????????????????????????????????fprintf(stderr,"%s\n",errbuf);??????????????????return;??????????}??????????pcap_dump_open(pt,?"t.pcap");??????????pt=pcap_open_live(dev,BUFSIZ,1,pcap_time_out,errbuf);??????????if(pt==NULL){??????????????????????????????????fprintf(stderr,"open?error?:%s\n",errbuf);??????????????????return;??????????}??????????sprintf(filter,"");??????????if(pcap_compile(pt,&fp,filter,0,netp)==-1)?{??????????????????????????????????fprintf(stderr,"compile?error\n");??????????????????return;??????????}??????????if(pcap_setfilter(pt,&fp)==-1)?{??????????????????????????????????fprintf(stderr,"setfilter?error\n");??????????????????return;??????????}????????????pcap_loop(pt,-1,ethernet_packet_callback,NULL);?????????????????????????????pcap_close(pt);??????????return?0;??}??
下面這個網址有一些例子：
http://blog.csdn.net/htttw/article/details/7521053
總結
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