src/listdevip.c

   1 // $Id: listdevip.c,v 1.1 2003/09/29 22:01:57 ensc Exp $
   2
   3 // Copyright (C) 2003 Enrico Scholz <enrico.scholz@informatik.tu-chemnitz.de>
   4 // based on listdevip.cc by Jacques Gelinas
   5 //
   6 // This program is free software; you can redistribute it and/or modify
   7 // it under the terms of the GNU General Public License as published by
   8 // the Free Software Foundation; either version 2, or (at your option)
   9 // any later version.
  10 //
  11 // This program is distributed in the hope that it will be useful,
  12 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 // GNU General Public License for more details.
  15 //
  16 // You should have received a copy of the GNU General Public License
  17 // along with this program; if not, write to the Free Software
  18 // Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  19
  20 /*
  21         Print the list of all network (IP) devices. Print the IP
  22         in fact, including all aliases.
  23 */
  24 #include <stdio.h>
  25 #include <stdlib.h>
  26 #include <string.h>
  27 #include <unistd.h>
  28 #include <sys/socket.h>
  29 #include <sys/ioctl.h>
  30 #include <netinet/in.h>
  31 #include <net/if.h>
  32
  33
  34 static int ifconfig_ioctl(
  35         int fd,
  36         const char *ifname,
  37         int cmd,
  38         struct ifreq *ifr)
  39 {
  40         strcpy(ifr->ifr_name, ifname);
  41         return ioctl(fd, cmd,ifr);
  42 }
  43
  44
  45 static int devlist_read2_2()
  46 {
  47         int ret = -1;
  48         int skfd = socket (AF_INET,SOCK_DGRAM,0);
  49         if (skfd < 0) {
  50                 perror ("socket");
  51         }else{
  52                 struct ifconf ifc;
  53                 int numreqs = 30;
  54                 ifc.ifc_buf = NULL;
  55                 ret = 0;
  56                 while (1) {
  57                         ifc.ifc_len = sizeof(struct ifreq) * numreqs;
  58                         ifc.ifc_buf = (char*)realloc(ifc.ifc_buf, ifc.ifc_len);
  59
  60                         if (ioctl(skfd, SIOCGIFCONF, &ifc) < 0) {
  61                                 perror("SIOCGIFCONF");
  62                                 ret = -1;
  63                                 break;
  64                         }
  65                         if (ifc.ifc_len == (int)sizeof(struct ifreq) * numreqs) {
  66                                 /* assume it overflowed and try again */
  67                                 numreqs += 10;
  68                                 continue;
  69                         }
  70                         break;
  71                 }
  72                 if (ret == 0){
  73                         struct ifreq *ifr = ifc.ifc_req;
  74                         int             n;
  75                         for (n = 0; n < ifc.ifc_len; n += sizeof(struct ifreq)) {
  76                                 struct sockaddr_in *sin = (struct sockaddr_in*)&ifr->ifr_addr;
  77                                 unsigned long addr = ntohl(sin->sin_addr.s_addr);
  78                                 unsigned long mask = 0xffffff00;
  79                                 struct ifreq ifmask;
  80                                 if (ifconfig_ioctl(skfd,ifr->ifr_name,SIOCGIFNETMASK, &ifmask) >= 0){
  81                                         struct sockaddr_in *sin = (struct sockaddr_in*)&ifmask.ifr_addr;
  82                                         mask = ntohl(sin->sin_addr.s_addr);
  83                                 }
  84
  85                                 printf ("%lu.%lu.%lu.%lu/%lu.%lu.%lu.%lu\n"
  86                                         ,(addr>>24)&0xff
  87                                         ,(addr>>16)&0xff
  88                                         ,(addr>>8)&0xff
  89                                         ,addr&0xff
  90                                         ,(mask>>24)&0xff
  91                                         ,(mask>>16)&0xff
  92                                         ,(mask>>8)&0xff
  93                                         ,mask&0xff);
  94                                 ifr++;
  95                         }
  96                 }
  97                 free(ifc.ifc_buf);
  98         }
  99         return ret;
 100 }
 101
 102 int main (int argc, char *argv[])
 103 {
 104         devlist_read2_2();
 105         return 0;
 106 }
 107