libpcap 개발 정리

C 언어/0x03-network

libpcap 개발 정리

SpeeDr00t 2014. 10. 12. 14:24

**pc에서 보셔야 잘보임니다...

libpcap 개발 정리
http://webdizen.new21.net/blog/tag/libpcap?TSSESSIONwwwwebdizennet=28ec2c8a6e6437f57135341e774b80fd

 libpcap 노광민 정리
http://kldp.org/KoreanDoc/Libpcap-KLDP

 --- sample code - 장경칩 일부 수정
Linux Fedora_191 2.6.21-1.3194.fc7 
 gcc -o test2 test2.c -lpcap

 THE CODE :

#include <stdio.h>
 #include <stdlib.h>
 #include <pcap.h> 
 #include <errno.h>
 #include <sys/socket.h>
 #include <netinet/in.h>
 #include <arpa/inet.h>
 #include <netinet/if_ether.h> 
 #include <linux/ip.h>
 #include <linux/icmp.h>

#include <net/ethernet.h>
 #include <netinet/tcp.h>
 #include <netinet/udp.h>
 #include <arpa/inet.h>

#include <netinet/ip6.h>

typedef unsigned char uchar;

void my_callback(u_char *notused,const struct pcap_pkthdr *pkthdr,const u_char* packet)
 {
 int i;
 struct ether_header *eptr;
 struct iphdr *ipptr;
 struct icmphdr *icmpptr;
 uchar *ptr;

if (packet == NULL)
 {
       printf("Didn't grab packet\n");
       exit(1);
  }

printf("Grabbed packet of length %d\n",pkthdr->len);
 //   printf("Recieved at ..... %s\n",ctime((const time_t*)&pkthdr->ts.tv_sec)); 
   printf("Ethernet address length is %d\n",ETHER_HDR_LEN);

eptr = (struct ether_header *) packet;

if (ntohs (eptr->ether_type) == ETHERTYPE_IP)
   {
       printf("Ethernet type is an IP packet\n");
       
       ipptr = (struct iphdr *) (eptr + 1);

if (ipptr->protocol == 1)
       {
         icmpptr = (struct icmphdr *) (ipptr + 1);
         if  (icmpptr->code == 16)
            printf("THIS IS A MOBILE IP ADVERTISEMENT PACKET\n");
       }
   }else  if (ntohs (eptr->ether_type) == ETHERTYPE_ARP)
   {
       printf("Ethernet type is an ARP packet\n");
   }else {
       printf("Ethernet type is someother Packet");
   }

ptr = eptr->ether_dhost;
   i = ETHER_ADDR_LEN;
   printf(" Destination Address:  ");
   do{
       printf("%s%x",(i == ETHER_ADDR_LEN) ? " " : ":",*ptr++);
   }while(--i>0);
   printf("\n");

ptr = eptr->ether_shost;
   i = ETHER_ADDR_LEN;
   printf(" Source Address:  ");
   do{
       printf("%s%x",(i == ETHER_ADDR_LEN) ? " " : ":",*ptr++);
   }while(--i>0);
   printf("\n");
 }

int main(int argc, char **argv)
 {
   int i,count = 20;
   char *dev="eth0";           /* (or "eth1" or "any or NULL") */
   char errbuf[PCAP_ERRBUF_SIZE];
   pcap_t* descr;
   const u_char *packet;

descr = pcap_open_live(dev,BUFSIZ,0,-1,errbuf);

if(descr == NULL)
   {
       printf("pcap_open_live(): %s\n",errbuf);
       exit(1);
   }

pcap_loop(descr,count,my_callback,NULL);
 return 0;
 }