arpdemo

2020/09/06 22:44

#include

#include /* 需要里面的 glibc 版本号 */

#if __GLIBC__ >= 2 && __GLIBC_MINOR >= 1

#include

#include /* 链路层（L2）协议 */

#else

#include

#include /* 链路层协议 */

#endif

#include

#define MAC_SIZE 18

#define IP_SIZE 16

// function declare

int get_ip_by_domain(const char *domain, char *ip); // 根据域名获取ip

int get_local_mac(const char *eth_inf, char *mac); // 获取本机mac

int get_local_ip(const char *eth_inf, char *ip); // 获取本机ip

#define INLEN 4

#define MAC_BCAST_ADDR (uint8_t *) "/xff/xff/xff/xff/xff/xff"

void usage_quit(char *arg0);

int get_ifi(char *dev, char *mac, int macln, struct in_addr *lc_addr, int ipln);

void prmac(u_char *ptr);

int main(int argc, char **argv)

{

if(argc != 2)

usage_quit(argv[0]);

int reqfd, recvfd, salen, n;

u_char *mac;

char recv_buf[120], rep_addr[16];

struct in_addr lc_addr, req_addr;

struct sockaddr_ll reqsa, repsa;

struct arp_pkt {

struct ether_header eh;

struct ether_arp ea;

u_char padding[18];

} req;

bzero(&reqsa, sizeof(reqsa));

reqsa.sll_family = PF_PACKET;

reqsa.sll_ifindex = if_nametoindex("eth0");

if((reqfd = socket(PF_PACKET, SOCK_RAW, htons(ETH_P_RARP))) < 0) {

perror("Socket error");

exit(1);

}

mac = (char *)malloc(ETH_ALEN);

bzero(&req, sizeof(req));

if(get_ifi("eth0", mac, ETH_ALEN, &lc_addr, INLEN)) {

fprintf(stderr, "Error: Get host’s information failed/n");

exit(0);

}

/* 填写以太网头部*/

memcpy(req.eh.ether_dhost, MAC_BCAST_ADDR, ETH_ALEN);

memcpy(req.eh.ether_shost, mac, ETH_ALEN);

req.eh.ether_type = htons(ETHERTYPE_ARP);

/* 填写arp数据 */

req.ea.arp_hrd = htons(ARPHRD_ETHER);

req.ea.arp_pro = htons(ETHERTYPE_IP);

req.ea.arp_hln = ETH_ALEN;

req.ea.arp_pln = INLEN;

req.ea.arp_op = htons(ARPOP_REQUEST);

memcpy(req.ea.arp_sha, mac, ETH_ALEN);

memcpy(req.ea.arp_spa, &lc_addr, INLEN);

inet_aton(argv[1], req.ea.arp_tpa);

if((n = sendto(reqfd, &req, sizeof(req), 0, (struct sockaddr *)&reqsa, sizeof(reqsa))) <= 0) {

perror("Sendto error");

exit(1);

}

printf("Broadcast arp request of %s, %d bytes be sent/n/n", argv[1], n);

recvfd = socket(PF_PACKET, SOCK_RAW, htons(ETH_P_ARP));

bzero(recv_buf, sizeof(recv_buf));

bzero(&repsa, sizeof(repsa));

salen = sizeof(struct sockaddr_ll);

while(1) {

if((n = recvfrom(recvfd, recv_buf, sizeof(req), 0, (struct sockaddr *)&repsa, &salen)) <= 0) {

perror("Recvfrom error");

exit(1);

}

if( ntohs(*(__be16 *)(recv_buf + 20))==2 && !memcmp(req.ea.arp_tpa, recv_buf + 28, 4) ) {

printf("Response from %s, %d bytes received/n", argv[1], n);

printf(" Peer IP is: %s/n", inet_ntop(AF_INET, (struct in_addr *)(recv_buf + 28), rep_addr, 1024));

prmac( (u_char *)(recv_buf + 22) ); //prmac( (u_char *)(recv_buf + 6) );

break;

}

free(mac);

}

int get_ifi(char *dev, char * mac, int macln, struct in_addr *lc_addr, int ipln)

{

int reqfd, n;

struct ifreq macreq;

reqfd = socket(AF_INET, SOCK_DGRAM, 0);

strcpy(macreq.ifr_name, dev);

/* 获取本地接口MAC地址*/

if(ioctl(reqfd, SIOCGIFHWADDR, ¯eq) != 0)

return 1;

memcpy(mac, macreq.ifr_hwaddr.sa_data, macln);

printf("MAC:%s\n", mac);

/* 获取本地接口IP地址*/

if(ioctl(reqfd, SIOCGIFADDR, ¯eq) != 0)

return 1;

memcpy(lc_addr, &((struct sockaddr_in *)(¯eq.ifr_addr))->sin_addr, ipln);

printf("IP:%s\n", lc_addr);

return 0;

}

void prmac(u_char *ptr)

{

printf(" Peer MAC is: %02x:%02x:%02x:%02x:%02x:%02x/n",*ptr,*(ptr+1),*(ptr+2),*(ptr+3),*(ptr+4),*(ptr+5));

}

void usage_quit(char *arg0)

{

fprintf(stderr, "Usage: %s \n", arg0);

exit(1);

}

// 根据域名获取ip

int get_ip_by_domain(const char *domain, char *ip)

{

char **pptr;

struct hostent *hptr;

hptr = gethostbyname(domain);

if(NULL == hptr)

{

printf("gethostbyname error for host:%s/n", domain);

return -1;

}

for(pptr = hptr->h_addr_list ; *pptr != NULL; pptr++)

{

if (NULL != inet_ntop(hptr->h_addrtype, *pptr, ip, IP_SIZE) )

{

return 0; // 只获取第一个 ip

}

return -1;

}

// 获取本机mac

int get_local_mac(const char *eth_inf, char *mac)

{

struct ifreq ifr;

int sd;

bzero(&ifr, sizeof(struct ifreq));

if( (sd = socket(AF_INET, SOCK_STREAM, 0)) < 0)

{

printf("get %s mac address socket creat error\n", eth_inf);

return -1;

}

strncpy(ifr.ifr_name, eth_inf, sizeof(ifr.ifr_name) - 1);

if(ioctl(sd, SIOCGIFHWADDR, &ifr) < 0)

{

printf("get %s mac address error\n", eth_inf);

close(sd);

return -1;

}

snprintf(mac, MAC_SIZE, "%02x:%02x:%02x:%02x:%02x:%02x",

(unsigned char)ifr.ifr_hwaddr.sa_data[0],

(unsigned char)ifr.ifr_hwaddr.sa_data[1],

(unsigned char)ifr.ifr_hwaddr.sa_data[2],

(unsigned char)ifr.ifr_hwaddr.sa_data[3],

(unsigned char)ifr.ifr_hwaddr.sa_data[4],

(unsigned char)ifr.ifr_hwaddr.sa_data[5]);

close(sd);

return 0;

}

// 获取本机ip

int get_local_ip(const char *eth_inf, char *ip)

{

int sd;

struct sockaddr_in sin;

struct ifreq ifr;

sd = socket(AF_INET, SOCK_DGRAM, 0);

if (-1 == sd)

{

printf("socket error: %s\n", strerror(errno));

return -1;

}

strncpy(ifr.ifr_name, eth_inf, IFNAMSIZ);

ifr.ifr_name[IFNAMSIZ - 1] = 0;

// if error: No such device

if (ioctl(sd, SIOCGIFADDR, &ifr) < 0)

{

printf("ioctl error: %s\n", strerror(errno));

close(sd);

return -1;

}

memcpy(&sin, &ifr.ifr_addr, sizeof(sin));

snprintf(ip, IP_SIZE, "%s", inet_ntoa(sin.sin_addr));

close(sd);

return 0;

}

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