SIOCGARP成功获取过arp的一个表项
/* getarp.c -- This simple program uses an IOCTL socket call to read an entry *//* from the ARP cache of the local machine. Original source unknown. */ /* Usage: getarp <ip-number> */ /* Example: getarp 148.85.2.1 */ #include <stdio.h> #include <stdlib.h> #include <string.h> #include <sys/types.h> #include <sys/socket.h> #include <sys/ioctl.h> #include <net/if.h> #include <netinet/in.h> #include <arpa/inet.h> #include <net/if_arp.h> /* arp_flags and at_flags field values */#define ATF_INUSE 0x01 /* entry in use */ #define ATF_COM 0x02 /* completed entry (enaddr valid) */ #define ATF_PERM 0x04 /* permanent entry */ #define ATF_PUBL 0x08 /* publish entry (respond for other host) */ #define ATF_USETRAILERS 0x10 /* has requested trailers */ #define ATF_PROXY 0x20 /* Do PROXY arp */ main (int argc, char *argv[]) { int s; struct arpreq arpreq; struct sockaddr_in *sin; unsigned char *eap; if (argc < 2) exit(0); memset(&arpreq, 0, sizeof(arpreq)); sin = (struct sockaddr_in *) &arpreq.arp_pa; sin->sin_family = AF_INET; sin->sin_addr.s_addr = inet_addr(argv[1]); s = socket(AF_INET, SOCK_DGRAM, 0); if (s < 0) { perror("socket"); exit(0); } if (ioctl(s, SIOCGARP, &arpreq) < 0) { perror("ioctl"); exit(0); } printf("IP address: %s\n", inet_ntoa(sin->sin_addr)); if (arpreq.arp_flags & ATF_COM) { eap = (unsigned char *) &arpreq.arp_ha.sa_data[0]; printf("Ethernet address: %02X:%02X:%02X:%02X:%02X:%02X", eap[0], eap[1], eap[2], eap[3], eap[4], eap[5]); if (arpreq.arp_flags & ATF_PERM) printf(" PERM"); if (arpreq.arp_flags & ATF_PUBL) printf(" PUBLISHED"); if (arpreq.arp_flags & ATF_USETRAILERS) printf(" TRAILERS"); if (arpreq.arp_flags & ATF_PROXY) printf(" PROXY"); printf("\n"); } else { printf("*** INCOMPLETE ***\n"); } close(s); exit(0); }
用arp -n命令查看我机子的arp表，只有192.168.1.1这个地址，于是我输入 “getarp 192.168.1.1”，可是却返回错误信息 ioctl: No such device。难道是这个程序有问题吗？我想问下谁试过用SIOCGARP成功获取过arp的一个表项?
你没有写设备选项
在44行上加上strcpy(arpreq.arp->dev, "eth0");试试