int sockfd=socket(PF_PACKET,SOCK_PACKET,htons(ETH_P_ALL))；//这个socket可以访问处理链路层及以上所有的数据包

int sockfd=socket(PF_PACKET,SOCK_RAW,htons(ETH_P_IP))；//这个socket可以访问处理链路层及以上所有的IP数据包

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdarg.h>
#include <time.h>#include <sys/types.h>
#include <sys/socket.h>
#include <sys/errno.h>
#include <sys/time.h>
#include <sys/ioctl.h>
#include <sys/stat.h>#include <net/if.h>
#include <net/ethernet.h>
#include <netinet/in.h>
#include <netinet/ip.h>
#include <netinet/if_ether.h>
#include <netpacket/packet.h>
#include <netdb.h>#include <arpa/inet.h>
#include <unistd.h>
#include <pthread.h>
#include <time.h>
#include <errno.h>
#include <fcntl.h>
#include <dirent.h>
#include <resolv.h>
#include <signal.h>
#include <getopt.h>
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif//首先定义网卡端口
#define PHYSICALPORT "eth0"
#define PHYSICALPORT_LEN 30//创建实际网卡端口数组
char physical_port[30];//定义缓存大小
#define BUFSIZE 1024*5
char sendbuf[BUFSIZE]={0};int main()
{memcpy(physical_port,PHYSICALPORT,PHYSICALPORT_LEN);int sock_send;sock_send=socket(PF_PACKET,SOCK_PACKET,htons(ETH_P_ALL));if(sock_send<0){perror("scoket created");   }//设置发包地址struct sockaddr send_addr;memset(&send_addr,0,sizeof(send_addr));strcpy(send_addr.sa_data,physical_port);//创建发送程序while(fgets(sendbuf,sizeof(sendbuf),stdin)!=0){int len=sendto(sock_send,&sendbuf,strlen(sendbuf),0,&send_addr,sizeof(send_addr));memset(sendbuf,0,sizeof(sendbuf));}return 0;
}

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdarg.h>
#include <time.h>#include <sys/types.h>
#include <sys/socket.h>
#include <sys/errno.h>
#include <sys/time.h>
#include <sys/ioctl.h>
#include <sys/stat.h>#include <net/if.h>
#include <net/ethernet.h>
#include <netinet/in.h>
#include <netinet/ip.h>
#include <netinet/if_ether.h>
#include <netpacket/packet.h>
#include <netdb.h>#include <arpa/inet.h>
#include <unistd.h>
#include <pthread.h>
#include <time.h>
#include <errno.h>
#include <fcntl.h>
#include <dirent.h>
#include <resolv.h>
#include <signal.h>
#include <getopt.h>
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif//首先定义网卡端口
#define PHYSICALPORT "eth0"
#define PHYSICALPORT_LEN 30//创建实际网卡端口数组
char physical_port[30];//定义缓存大小
#define BUFSIZE 1024*5
char recvbuf[BUFSIZE]={0};void ethernet_setpormisc(int fd,int i_flags);int main()
{memcpy(physical_port,PHYSICALPORT,PHYSICALPORT_LEN);//首先创建一个原始套接字int sock_recv;sock_recv=socket(PF_PACKET,SOCK_RAW,htons(ETH_P_ALL));if(sock_recv<0){perror("physicl socket created");}//设置网卡为混杂模式；ethernet_setpormisc(sock_recv,1);//setsockoptint recvbuf_size=BUFSIZE;setsockopt(sock_recv,SOL_SOCKET,SO_RCVBUF,&recvbuf,sizeof(char));//获取物理网卡接口索，用以传输数据struct ifreq ifr_recv;strcpy(ifr_recv.ifr_name,physical_port);if(ioctl(sock_recv,SIOCGIFINDEX,&ifr_recv)<0){perror("[3]get interface index");}   //绑定物理网卡struct sockaddr_ll local_addr;local_addr.sll_family=PF_PACKET;local_addr.sll_ifindex=ifr_recv.ifr_ifindex;local_addr.sll_protocol=htons(ETH_P_ALL);if((bind(sock_recv,(struct sockaddr *)&local_addr,sizeof(local_addr)))<0){perror("[4]bind physical address");}   //开始接收数据包while(1){recvfrom(sock_recv,recvbuf,BUFSIZE,0,NULL,NULL);printf("%s",recvbuf);memset(recvbuf,0,sizeof(recvbuf));}   close(sock_recv);
}//创建设置网卡混杂模式函数
void ethernet_setpormisc(int fd,int i_flags)
{//首先获取网卡接口标志位struct ifreq ifr_s;memcpy(ifr_s.ifr_name,physical_port,sizeof(physical_port));if(ioctl(fd,SIOCGIFFLAGS,&ifr_s)<0){perror("[1]get interface flags");}if(i_flags==0){//取消混杂模式ifr_s.ifr_flags &= ~IFF_PROMISC;}else{//设置为混杂模式ifr_s.ifr_flags |= IFF_PROMISC;}   //将接口设置为相应的模式if(ioctl(fd,SIOCSIFFLAGS,&ifr_s)<0){perror("[2]set interface flags");}
}