linux原始套接字编程之收发链路层广播(收端)


#include <stdlib.h>

#include <stdio.h>

#include <string.h>

#include <errno.h>

#include <sys/types.h>

#include <sys/socket.h>

#include <linux/if_ether.h>

#include <netpacket/packet.h>

#include <net/if.h>

#include <netinet/in.h>

#include <arpa/inet.h>

#include <unistd.h>

#define ETH_ALEN 6

#define ETH_P_GATE 0x9006

#define ETH_MAX_DATA_LEN 1488

#define ETH_HEAD_LEN 16

#define ETH_BODY_LEN 1496

#define ETH_LEN ETH_HEAD_LEN + ETH_BODY_LEN

struct EtherHead

{

 unsigned char   dest[ETH_ALEN];   /* destinat    ion eth addr */

 unsigned char   source[ETH_ALEN]; /* source e    ther addr    */

 unsigned int    proto;        /* packet type     ID field */

};

struct EtherBody

{

 size_t datalen;

 char data[ETH_MAX_DATA_LEN];

};

int main()

{

 //创建原始套接字

 int sock = socket(PF_PACKET, SOCK_RAW, htons(ETH_P_GATE));

 if (0 > sock)

 {

  printf("create_sock err %s",  strerror(errno));

  return -1;

 }

 

 //获取网卡信息

 struct ifreq ifr;

 memset(&ifr, 0, sizeof(struct ifreq));

 memcpy(ifr.ifr_name, "eth0", strlen("eth0") + 1);

 ifr.ifr_ifindex = if_nametoindex(ifr.ifr_name);

 

 struct sockaddr_ll sk_ll;

 sk_ll.sll_family = AF_PACKET;

 sk_ll.sll_protocol = htons(ETH_P_GATE);

 sk_ll.sll_hatype = 1;

 sk_ll.sll_halen = ETH_ALEN;

 sk_ll.sll_pkttype = PACKET_MULTICAST;

 sk_ll.sll_ifindex = ifr.ifr_ifindex;//指定网卡

 

 if(0 < bind(sock, (struct sockaddr *)&sk_ll, sizeof(struct sockaddr_ll)))

 {

  printf("bind err %s", strerror(errno));

  exit(0);

 } 

 void *buf = malloc(1512);

 struct sockaddr_in recv;

 socklen_t recvlen = 0;

 while(1)

 {

  if(-1 == recvfrom(sock, buf, 1512, 0, (struct sockaddr *)&recv,  &recvlen))

  {

   printf("sendto err %s",  strerror(errno));

   exit(-1);

  }

  //struct EtherBody *eth = NULL;

  //memcpy(eth, buf+ETH_HEAD_LEN, ETH_BODY_LEN);

  //printf("%s\n", eth->data);

  printf("data:%s\n", ((struct EtherBody *)(buf+ETH_HEAD_LEN))->data);

  sleep(1);

 }

}