ARP的C代码实现

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<h2 id="t_412ef3420100mvbp" class="titName SG_txta">linux下C语言实现ARP数据包发送</h2>#include <netdb.h>#include <sys/socket.h>#include <sys/types.h>#include <stdio.h>#include <errno.h>#include <sys/ioctl.h>#include <net/if.h>#include <signal.h>#include <netinet/ip.h>#include <netinet/in.h>#include <string.h>#include <arpa/inet.h>#include <netinet/ip_icmp.h>#include <linux/if_ether.h>#define ETH_HW_ADDR_LEN 6#define IP_ADDR_LEN 4#define ARP_FRAME_TYPE 0x0806#define ETHER_HW_TYPE 1#define IP_PROTO_TYPE 0x0800#define OP_ARP_REQUEST 2#define OP_ARP_QUEST 1#define DEFAULT_DEVICE "eth0"char usage[] ={"send_arp: sends out custom ARP packet. ferrysnow@gmail.com \nusage : send_arp src_ip_addr src_hw_addr targ_ip_addr tar_hw_addr number"};struct arp_packet{u_char targ_hw_addr[ETH_HW_ADDR_LEN];u_char src_hw_addr[ETH_HW_ADDR_LEN];u_short frame_type;u_short hw_type;u_short prot_type;u_char hw_addr_size;u_char prot_addr_size;u_short op;u_char sndr_hw_addr[ETH_HW_ADDR_LEN];u_char sndr_ip_addr[IP_ADDR_LEN];u_char rcpt_hw_addr[ETH_HW_ADDR_LEN];u_char rcpt_ip_addr[IP_ADDR_LEN];u_char padding[18];};void die(char*);void get_ip_addr(struct in_addr*, char*);void get_hw_addr(char*, char*);int main(int argc, char* argv[]){        struct in_addr src_in_addr, targ_in_addr;        struct arp_packet pkt;        struct sockaddr sa;        int sock;        int j, number;        if (argc != 6)        {                die(usage);        }        sock = socket(AF_INET, SOCK_PACKET, htons(ETH_P_RARP));        if (sock < 0)        {                perror("socket");                exit(1);        }        number = atoi(argv[5]);        pkt.frame_type = htons(ARP_FRAME_TYPE);        pkt.hw_type = htons(ETHER_HW_TYPE);        pkt.prot_type = htons(IP_PROTO_TYPE);        pkt.hw_addr_size = ETH_HW_ADDR_LEN;        pkt.prot_addr_size = IP_ADDR_LEN;        pkt.op = htons(OP_ARP_QUEST);        get_hw_addr(pkt.targ_hw_addr, argv[4]);        get_hw_addr(pkt.rcpt_hw_addr, argv[4]);        get_hw_addr(pkt.src_hw_addr, argv[2]);        get_hw_addr(pkt.sndr_hw_addr, argv[2]);        get_ip_addr(&src_in_addr, argv[1]);        get_ip_addr(&targ_in_addr, argv[3]);        memcpy(pkt.sndr_ip_addr, &src_in_addr, IP_ADDR_LEN);        memcpy(pkt.rcpt_ip_addr, &targ_in_addr, IP_ADDR_LEN);        bzero(pkt.padding, 18);        strcpy(sa.sa_data, DEFAULT_DEVICE);        for (j = 0; j < number; j++)        {                if (sendto(sock, &pkt, sizeof(pkt), 0, &sa, sizeof(sa)) < 0)                {                        perror("sendto");                        exit(1);                }        }        exit(0);}void die(char* str){        fprintf(stderr, "%s\n", str);        exit(1);}void get_ip_addr(struct in_addr* in_addr, char* str){        struct hostent* hostp;        in_addr->s_addr = inet_addr(str);        if (in_addr->s_addr == -1)        {                if ((hostp = gethostbyname(str)))                {                        bcopy(hostp->h_addr, in_addr, hostp->h_length);                }                else                {                        fprintf(stderr, "send_arp: unknown host %s\n", str);                        exit(1);                }        }}void get_hw_addr(char* buf, char* str){        int i;        char c, val;        for (i = 0; i < ETH_HW_ADDR_LEN; i++)        {                if (!(c = tolower(*str++)))                {                        die("Invalid hardware address");                }                if (isdigit(c))                {                        val = c - '0';                }                else if (c >= 'a' && c <= 'f')                {                        val = c - 'a' + 10;                }                else                {                        die("Invalid hardware address");                }                *buf = val << 4;                if (!(c = tolower(*str++)))                {                        die("Invalid hardware address");                }                if (isdigit(c))                {                        val = c - '0';                }                else if (c >= 'a' && c <= 'f')                {                        val = c - 'a' + 10;                }                else                {                        die("Invalid hardware address");                }                *buf++ |= val;                if (*str == ':')                {                        str++;                }        }}


ARP协议的c语言实现源代码

#include <netdb.h>#include <unistd.h>#include <ctype.h>#include <errno.h>#include <signal.h>#include <string.h>#include <stdio.h>#include <stdlib.h>#include <getopt.h>#include <sys/uio.h>#include <sys/file.h>#include <sys/time.h>#include <sys/signal.h>#include <sys/ioctl.h>#include <sys/param.h>#include <sys/socket.h>#include <linux/sockios.h>#include <linux/if.h>#include <linux/if_arp.h>#include <linux/if_packet.h>#include <linux/types.h>#include <netinet/in.h>#include <arpa/inet.h>#define src_addr "192.168.0.239"#define device  "eth0"#define fill_buf "aaaaaaaaaaaa"int socket_id;char *target = src_addr;int send_count = 0;int recv_count = 0;struct in_addr  src, dst;struct sockaddr_ll   me,  he;struct timeval   send_time, recv_time;struct in_addr get_src_ip(char * devices){struct sockaddr_in saddr;int sock_id = socket(AF_INET, SOCK_DGRAM, 0);if (sock_id < 0) {  perror("socket");  exit(2);}if (devices) {      if (setsockopt(sock_id, SOL_SOCKET, SO_BINDTODEVICE, device, strlen(device)+1) == -1)   perror("WARNING: interface is ignored");}int alen = sizeof(saddr);memset(&saddr, 0, sizeof(saddr));saddr.sin_port = htons(0x1000);saddr.sin_family = AF_INET; if (connect(sock_id, (struct sockaddr*)&saddr, sizeof(saddr)) == -1) {  perror("connect");  exit(2);}if (getsockname(sock_id, (struct sockaddr*)&saddr, &alen) == -1) {  perror("getsockname");  exit(2);}close(sock_id);return saddr.sin_addr;}int check_device(char* if_dev, int ss){int ifindex;struct ifreq ifr;memset(&ifr, 0, sizeof(ifr));strncpy(ifr.ifr_name, if_dev, IFNAMSIZ-1);  if (ioctl(ss, SIOCGIFINDEX, &ifr) < 0) {   fprintf(stderr, "arping: unknown iface %s\n", if_dev);   exit(2);  }  ifindex = ifr.ifr_ifindex;  if (ioctl(ss, SIOCGIFFLAGS, (char*)&ifr)) {   perror("ioctl(SIOCGIFFLAGS)");   exit(2);  }  if (!(ifr.ifr_flags&IFF_UP)) {    printf("Interface \"%s\" is down\n", if_dev);   exit(2);  }  if (ifr.ifr_flags&(IFF_NOARP|IFF_LOOPBACK)) {    printf("Interface \"%s\" is not ARPable\n", if_dev);   exit(2);  }return ifindex;} // check_device()int socket_init(){int s,  s_errno;s = socket(PF_PACKET,  SOCK_DGRAM,  0);s_errno = errno;me.sll_family = AF_PACKET;me.sll_ifindex = check_device(device,  s);me.sll_protocol = htons(ETH_P_ARP);if (bind(s,  (struct sockaddr*)&me,  sizeof(me)) == -1) {  perror("bind");  exit(2); }int alen = sizeof(me);if (getsockname(s, (struct sockaddr*)&me, &alen) == -1) {  perror("getsockname");  exit(2);}if (me.sll_halen == 0) {  printf("Interface \"%s\" is not ARPable (no ll address)\n", device);  exit(2);}he = me;memset(he.sll_addr, -1, he.sll_halen);  // set dmac addr FF:FF:FF:FF:FF:FFreturn s;}intcreate_pkt(unsigned char * buf, struct in_addr src, struct in_addr dst, struct sockaddr_ll * FROM, struct sockaddr_ll * TO){struct arphdr *ah = (struct arphdr*) buf;unsigned char *p = (unsigned char *)(ah+1);ah->ar_hrd = htons(FROM->sll_hatype);if (ah->ar_hrd == htons(ARPHRD_FDDI))  ah->ar_hrd = htons(ARPHRD_ETHER);ah->ar_pro = htons(ETH_P_IP);ah->ar_hln = FROM->sll_halen;ah->ar_pln = 4;ah->ar_op  =  htons(ARPOP_REQUEST);memcpy(p, &FROM->sll_addr, ah->ar_hln);p+=FROM->sll_halen;memcpy(p, &src, 4);p+=4;memcpy(p, &TO->sll_addr, ah->ar_hln);p+=ah->ar_hln;memcpy(p, &dst, 4);p+=4;memcpy(p, fill_buf, strlen(fill_buf) );p+=12;return  (p-buf);}void send_pkt(){unsigned char send_buf[256];int pkt_size = create_pkt(send_buf,  src,  dst,  &me,  &he);gettimeofday(&send_time, NULL); int cc = sendto(socket_id, send_buf, pkt_size, 0, (struct sockaddr*)&he, sizeof(he));if( cc == pkt_size )  send_count++; alarm(1);}int chk_recv_pkt(unsigned char * buf, struct sockaddr_ll * FROM){struct arphdr *ah = (struct arphdr*)buf;unsigned char *p = (unsigned char *)(ah+1);struct in_addr src_ip, dst_ip;if (ah->ar_op != htons(ARPOP_REQUEST) &&  ah->ar_op != htons(ARPOP_REPLY))  return 0;if (ah->ar_pro != htons(ETH_P_IP) || ah->ar_pln != 4 || ah->ar_hln != me.sll_halen )  return 0;memcpy(&src_ip, p+ah->ar_hln, 4);memcpy(&dst_ip, p+ah->ar_hln+4+ah->ar_hln, 4);if (src_ip.s_addr != dst.s_addr || src.s_addr != dst_ip.s_addr )  return 0;return (p-buf);}void disp_info(int received,  struct in_addr dst, int msecs, int usecs, struct sockaddr_ll from){printf("%03d ", received);printf("%s ", from.sll_pkttype==PACKET_HOST ? "Unicast" : "Broadcast");printf("%s from %s",  "reply",   inet_ntoa(dst) );printf(" [%02X:%02X:%02X:%02X:%02X:%02X] ", from.sll_addr[0], from.sll_addr[1], \  from.sll_addr[2], from.sll_addr[3], from.sll_addr[4], from.sll_addr[5]);   printf(" %ld.%ld ms\n", (long int)msecs, (long int)usecs);fflush(stdout);}void finish(){printf("\nSent %d ARP probe packet(s) \n", send_count);printf("Received %d response(s)", recv_count);printf("\n\n");fflush(stdout);exit(!recv_count);}////////////////////////////////////////////////////////////////intmain(int argc, char **argv){uid_t uid = getuid();setuid(uid);if( *(argv+1) != NULL )  target = *(argv+1);if (inet_aton(target, &dst) != 1) {  struct hostent *hp;  hp = gethostbyname2(target, AF_INET);  printf("\ntarget = %s \n", target );  if (!hp) {   fprintf(stderr, "arping: unknown host %s\n", target);   exit(2);  }  memcpy(&dst, hp->h_addr, 4);}src =  get_src_ip(device);if (!src.s_addr ) {  fprintf(stderr, "arping: no source address in not-DAD mode\n");  exit(2);}socket_id = socket_init();printf("\nARPING %s ", inet_ntoa(dst));printf("from %s %s\n\n",  inet_ntoa(src), device ? : "");signal(SIGINT,   finish);signal(SIGALRM, send_pkt);send_pkt();while(1){  struct sockaddr_ll from;  int alen = sizeof(from);  char recv_buf[0x1000];   int recv_size = recvfrom(socket_id, recv_buf,  sizeof(recv_buf), 0,  (struct sockaddr *)&from, &alen );   gettimeofday(&recv_time, NULL);   if( recv_size < 0 ) {   perror("arping: recvfrom");   continue;  }  if( chk_recv_pkt(recv_buf, &from) > 0 ) {   memcpy(he.sll_addr, from.sll_addr, he.sll_halen);     long usecs, msecs;   if (recv_time.tv_sec) {    usecs = (recv_time.tv_sec - send_time.tv_sec) * 1000000 + recv_time.tv_usec - send_time.tv_usec;    msecs = (usecs+500)/1000;    usecs -= msecs*1000 - 500;   }      recv_count++;   disp_info(recv_count,  dst,  msecs,  usecs,  from);       } // if (chk...)    }return 0;}

免费ARP简单介绍和程序编写

免费ARP,在网络上有很多的介绍。在《tcp/ip协议卷》中的第四章也有介绍,下面再啰嗦一下介绍其作用和操作:

免费ARP,主要用于检测网络中IP地址是否冲突,它是一种功能而非协议。当设备重启或代理ARP功能开启时就会向本地网络主动发免费ARP以检测IP地址是否冲突。免费ARP是以源、目的IP都是自己,源MAC也是自己,目标MAC是广播,即向自己所在网络请求自己的MAC地址,当网络中如果有其他主机使用了与自己相同的IP地址,他就会给主机一个ARP回复,此时如果发免费ARP的主机收到了回复就证明自己所用的IP地址有冲突,如果没有收到回复则说明没有IP地址冲突。

(若上面的文字有雷同,则以别人的文章为主;若有版权请告知我,本人会在24小时撤掉,谢谢~~~)

下面是免费ARP的代码,作为一个参考吧:

[cpp] view plaincopy
  1. /////////////////////////////////////////////////////////////////////////////////  
  2. // 文件名: arp_func.c  
  3. // 作者:   cfjtaishan  
  4. // 版本:   1.0  
  5. // 日期:   2013-05-14  
  6. // 描述:   免费ARP--用于检测IP地址是否冲突.  
  7. // 历史记录:  
  8. /////////////////////////////////////////////////////////////////////////////////  
  9.   
  10.   
  11. #include <stdio.h>  
  12. #include <stdlib.h>  
  13. #include <string.h>  
  14. #include <errno.h>  
  15. #include <sys/types.h>  
  16. #include <sys/socket.h>  
  17. #include <linux/if_packet.h>  
  18. #include <netdb.h>  
  19. #include <unistd.h>  
  20. #include <arpa/inet.h>  
  21. #include <sys/ioctl.h>  
  22. #include <net/ethernet.h>  
  23. #include <netinet/ether.h>  
  24. #include <net/if.h>  
  25. #include <netinet/ip.h>  
  26.   
  27. #define    FAILURE   -1  
  28. #define    SUCCESS    0  
  29.   
  30. unsigned char src_ip[4] = { 192, 168, 9, 118 };    //要检测的主机IP地址  
  31. unsigned char src_mac[6] = {0x00, 0x0c, 0x29, 0x4b, 0x6c, 0x13};    //要检测的主机的MAC地址  
  32. unsigned char dst_ip[4] = { 192, 168, 9, 118 };    //目标IP地址  
  33. unsigned char dst_mac[6] = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };    //ARP广播地址  
  34.   
  35. int send_arp(int sockfd, struct sockaddr_ll *peer_addr);  
  36. int recv_arp(int sockfd, struct sockaddr_ll *peer_addr);  
  37.   
  38. //ARP封装包  
  39. typedef struct _tagARP_PACKET{    
  40.     struct ether_header  eh;    
  41.     struct ether_arp arp;    
  42. }ARP_PACKET_OBJ, *ARP_PACKET_HANDLE;   
  43.   
  44. int main(int argc, char *argv[])  
  45. {  
  46.     int sockfd;  
  47.     int rtval = -1;  
  48.     struct sockaddr_ll peer_addr;  
  49.     //创建socket  
  50.     sockfd = socket(AF_PACKET, SOCK_RAW, htons(ETH_P_ARP));  
  51.     if (sockfd < 0)  
  52.     {  
  53.         fprintf(stderr, "socket error: %s\n", strerror(errno));  
  54.         exit(EXIT_FAILURE);  
  55.     }  
  56.       
  57.     memset(&peer_addr, 0, sizeof(peer_addr));    
  58.         peer_addr.sll_family = AF_PACKET;    
  59.         struct ifreq req;  
  60.     bzero(&req, sizeof(struct ifreq));  
  61.         strcpy(req.ifr_name, "eth0");    
  62.         if(ioctl(sockfd, SIOCGIFINDEX, &req) != 0)  
  63.         perror("ioctl()");    
  64.         peer_addr.sll_ifindex = req.ifr_ifindex;    
  65.         peer_addr.sll_protocol = htons(ETH_P_ARP);  
  66.     //peer_addr.sll_family = AF_PACKET;  
  67.     while (1)  
  68.     {  
  69.         rtval = send_arp(sockfd, &peer_addr);  
  70.         if (FAILURE == rtval)  
  71.         {  
  72.             fprintf(stderr, "Send arp socket failed: %s\n", strerror(errno));  
  73.         }  
  74.         rtval = recv_arp(sockfd, &peer_addr);  
  75.         if (rtval == SUCCESS)  
  76.         {  
  77.             printf ("Get packet from peer and IP conflicts!\n");  
  78.         }  
  79.         else if (rtval == FAILURE)  
  80.         {  
  81.             fprintf(stderr, "Recv arp IP not conflicts: %s\n", strerror(errno));  
  82.         }  
  83.         else  
  84.         {  
  85.             fprintf(stderr, "Recv arp socket failed: %s\n", strerror(errno));  
  86.         }  
  87.         //sleep(1);  
  88.     }  
  89.     return 0;  
  90. }  
  91. //////////////////////////////////////////////////////////////////////////  
  92. // 函数名: send_arp   
  93. // 描述 : 填充ARP数据包报文并发送出去。  
  94. // 参数:   
  95. //    [in] sockfd -- 创建的socket描述符;  
  96. //    [in] peer_addr -- 对端的IP信息  
  97. // 返回值:   
  98. //    成功: SUCCESS, 失败: FAILURE;  
  99. // 说明:   
  100. //////////////////////////////////////////////////////////////////////////  
  101. int send_arp(int sockfd, struct sockaddr_ll *peer_addr)  
  102. {  
  103.     int rtval;  
  104.     ARP_PACKET_OBJ frame;  
  105.     memset(&frame, 0x00, sizeof(ARP_PACKET_OBJ));  
  106.       
  107.     //填充以太网头部  
  108.         memcpy(frame.eh.ether_dhost, dst_mac, 6);    //目的MAC地址  
  109.         memcpy(frame.eh.ether_shost, src_mac, 6);    //源MAC地址  
  110.         frame.eh.ether_type = htons(ETH_P_ARP);      //协议   
  111.   
  112.     //填充ARP报文头部  
  113.         frame.arp.ea_hdr.ar_hrd = htons(ARPHRD_ETHER);    //硬件类型   
  114.         frame.arp.ea_hdr.ar_pro = htons(ETHERTYPE_IP);    //协议类型 ETHERTYPE_IP | ETH_P_IP  
  115.         frame.arp.ea_hdr.ar_hln = 6;                //硬件地址长度  
  116.         frame.arp.ea_hdr.ar_pln = 4;                //协议地址长度  
  117.         frame.arp.ea_hdr.ar_op = htons(ARPOP_REQUEST);    //ARP请求操作  
  118.         memcpy(frame.arp.arp_sha, src_mac, 6);    //源MAC地址  
  119.         memcpy(frame.arp.arp_spa, src_ip, 4);     //源IP地址  
  120.         memcpy(frame.arp.arp_tha, dst_mac, 6);    //目的MAC地址  
  121.         memcpy(frame.arp.arp_tpa, dst_ip, 4);     //目的IP地址  
  122.       
  123.         rtval = sendto(sockfd, &frame, sizeof(ARP_PACKET_OBJ), 0,   
  124.         (struct sockaddr*)peer_addr, sizeof(struct sockaddr_ll));    
  125.     if (rtval < 0)  
  126.     {  
  127.         return FAILURE;  
  128.     }  
  129.     return SUCCESS;  
  130. }  
[cpp] view plaincopy
  1. //////////////////////////////////////////////////////////////////////////  
  2. // 函数名: recv_arp   
  3. // 描述 : 接收ARP回复数据报文并判断是不是对免费ARP的回复。  
  4. // 参数:   
  5. //    [in] sockfd -- 创建的socket描述符;  
  6. //    [in] peer_addr -- 对端的IP信息  
  7. // 返回值:   
  8. //    成功: SUCCESS, 失败: FAILURE;  
  9. // 说明:   
  10. //    若是对免费arp请求的回复则返回:SUCCESS.  
  11. //////////////////////////////////////////////////////////////////////////  
  12. int recv_arp(int sockfd, struct sockaddr_ll *peer_addr)  
  13. {  
  14.     int rtval;  
  15.     ARP_PACKET_OBJ frame;  
  16.       
  17.     memset(&frame, 0, sizeof(ARP_PACKET_OBJ));  
  18.     rtval = recvfrom(sockfd, &frame, sizeof(frame), 0,   
  19.         NULL, NULL);  
  20.     //判断是否接收到数据并且是否为回应包  
  21.     if (htons(ARPOP_REPLY) == frame.arp.ea_hdr.ar_op && rtval > 0)  
  22.     {  
  23.         //判断源地址是否为冲突的IP地址  
  24.         if (memcmp(frame.arp.arp_spa, src_ip, 4) == 0)  
  25.         {  
  26.             fprintf(stdout, "IP address is common~\n");  
  27.             return SUCCESS;  
  28.         }  
  29.     }  
  30.     if (rtval < 0)  
  31.     {  
  32.         return FAILURE;  
  33.     }  
  34.     return FAILURE;  
  35. }  

该程序可以测试局域网中的某个IP地址是否有冲突的,以便于确定该地址是否可以作为本机的IP地址。下面是通过wireshark抓到了免费的ARP数据包,以及回应包,如下:

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