1 #include <sys/types.h> 2 #include <sys/socket.h> 3 #include <net/if.h> 4 #include <net/if_dl.h> 5 #include <netinet/in.h> 6 #include <arpa/inet.h> 7 #include <sys/ioctl.h> 8 #include <stdlib.h> 9 10 int printaddr( const struct sockaddr *sa )11 {12     if( sa->sa_family == AF_LINK ) {13         struct sockaddr_dl *sdl = (struct sockaddr_dl *)sa;14         int len = sdl->sdl_alen - 1, i;15         16         printf("\tAF_LINK\t");17         for( i = 0; i < len; i++ ) {18             printf("%02X:", (unsigned char)(sdl->sdl_data)[ sdl->sdl_nlen + i] );19         }20         printf( "%02X", (sdl->sdl_data)[ sdl->sdl_nlen + i] );21     }22     else if( sa->sa_family == AF_INET ) {23         struct sockaddr_in *sin = (struct sockaddr_in *)sa;24         printf("\tAF_INET\t");25         printf("%s:%d", inet_ntoa(sin->sin_addr), ntohs(sin->sin_port));26     }27 }28 29 int main(void)30 {31     struct ifconf ifc;32     char buffer[200];33     int len;34     struct ifreq *ifrp;35     36     len = socket(AF_INET, SOCK_STREAM, 0);37     38     ifc.ifc_len = sizeof( buffer );39     ifc.ifc_buf = buffer;40     if( ioctl(len, SIOCGIFCONF, &ifc) < 0 )41     {42         perror("ioctl error");43         return -1;44     }45     46     len = ifc.ifc_len;47     ifrp = ifc.ifc_req;48     for(; len > 0 && ifrp; ) {49         struct sockaddr *sa = &(ifrp->ifr_addr);50         printf("%s", ifrp->ifr_name);51         printaddr( sa );52         printf("\n");53         54         ifrp = (struct ifreq *)((char *)sa + sa->sa_len);55         len -= sizeof(ifrp->ifr_name) + sa->sa_len;56     }57     58     return 0;59 }