/***************SimpelSniffer.c*************/
#include <stdio.h>#include <unistd.h>#include <sys/socket.h>#include <sys/types.h>#include <linux/if_ether.h>#include <linux/in.h>#define BUFFER_MAX 2048
int main(int argc, char *argv[]){		int sock, n_read, proto;		char buffer[BUFFER_MAX];	char *ethhead, *iphead, *tcphead, *udphead, *icmphead, *p;		if((sock = socket(PF_PACKET, SOCK_RAW, htons(ETH_P_IP))) < 0)	{		fprintf(stdout, "create socket error\n");		exit(0);	}	while(1) 	{		n_read = recvfrom(sock, buffer, 2048, 0, NULL, NULL);		/*		14   6(dest)+6(source)+2(type or length)		+		20   ip header 		+		8    icmp,tcp or udp header		= 42		*/		if(n_read < 42) 		{			fprintf(stdout, "Incomplete header, packet corrupt\n");			continue;		}				ethhead = buffer;		p = ethhead;		int n = 0XFF;		printf("MAC: %.2X:%02X:%02X:%02X:%02X:%02X==>"			"%.2X:%.2X:%.2X:%.2X:%.2X:%.2X\n",			p[6]&n, p[7]&n, p[8]&n, p[9]&n, p[10]&n, p[11]&n,			p[0]&n, p[1]&n, p[2]&n, p[3]&n, p[4]&n, p[5]&n);
        iphead = ethhead + 14;          p = iphead + 12;                printf("IP: %d.%d.%d.%d => %d.%d.%d.%d\n",			p[0]&0XFF, p[1]&0XFF, p[2]&0XFF, p[3]&0XFF,			p[4]&0XFF, p[5]&0XFF, p[6]&0XFF, p[7]&0XFF);				proto = (iphead + 9)[0];		p = iphead + 20;		printf("Protocol: ");		switch(proto)		{        case IPPROTO_ICMP: printf("ICMP\n");break;        case IPPROTO_IGMP: printf("IGMP\n");break;        case IPPROTO_IPIP: printf("IPIP\n");break;        case IPPROTO_TCP :        case IPPROTO_UDP : printf("%s,", proto == IPPROTO_TCP ? "TCP": "UDP"); 			printf("source port: %u,",(p[0]<<8)&0XFF00 |  p[1]&0XFF);			printf("dest port: %u\n", (p[2]<<8)&0XFF00 | p[3]&0XFF);			break;        case IPPROTO_RAW : printf("RAW\n");break;        default:printf("Unkown, please query in include/linux/in.h\n");		}	}}