src/listdevip.c

   1 // $Id: listdevip.c,v 1.3 2004/02/20 16:59:40 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 #ifdef HAVE_CONFIG_H
  25 #  include <config.h>
  26 #endif
  27 #include "compat.h"
  28
  29 #include <stdio.h>
  30 #include <stdlib.h>
  31 #include <string.h>
  32 #include <unistd.h>
  33 #include <sys/socket.h>
  34 #include <sys/ioctl.h>
  35 #include <netinet/in.h>
  36 #include <net/if.h>
  37
  38
  39 static int ifconfig_ioctl(
  40         int fd,
  41         const char *ifname,
  42         int cmd,
  43         struct ifreq *ifr)
  44 {
  45         strcpy(ifr->ifr_name, ifname);
  46         return ioctl(fd, cmd,ifr);
  47 }
  48
  49
  50 static int devlist_read2_2()
  51 {
  52         int ret = -1;
  53         int skfd = socket (AF_INET,SOCK_DGRAM,0);
  54         if (skfd < 0) {
  55                 perror ("listdevip: socket()");
  56         }else{
  57                 struct ifconf ifc;
  58                 int numreqs = 30;
  59                 ifc.ifc_buf = NULL;
  60                 ret = 0;
  61                 while (1) {
  62                         ifc.ifc_len = sizeof(struct ifreq) * numreqs;
  63                         ifc.ifc_buf = (char*)realloc(ifc.ifc_buf, ifc.ifc_len);
  64
  65                         if (ioctl(skfd, SIOCGIFCONF, &ifc) < 0) {
  66                                 perror("listdevip: SIOCGIFCONF");
  67                                 ret = -1;
  68                                 break;
  69                         }
  70                         if (ifc.ifc_len == (int)sizeof(struct ifreq) * numreqs) {
  71                                 /* assume it overflowed and try again */
  72                                 numreqs += 10;
  73                                 continue;
  74                         }
  75                         break;
  76                 }
  77                 if (ret == 0){
  78                         struct ifreq *ifr = ifc.ifc_req;
  79                         int             n;
  80                         for (n = 0; n < ifc.ifc_len; n += sizeof(struct ifreq)) {
  81                                 struct sockaddr_in *sin = (struct sockaddr_in*)&ifr->ifr_addr;
  82                                 unsigned long addr = ntohl(sin->sin_addr.s_addr);
  83                                 unsigned long mask = 0xffffff00;
  84                                 struct ifreq ifmask;
  85                                 if (ifconfig_ioctl(skfd,ifr->ifr_name,SIOCGIFNETMASK, &ifmask) >= 0){
  86                                         struct sockaddr_in *sin = (struct sockaddr_in*)&ifmask.ifr_addr;
  87                                         mask = ntohl(sin->sin_addr.s_addr);
  88                                 }
  89
  90                                 printf ("%lu.%lu.%lu.%lu/%lu.%lu.%lu.%lu\n"
  91                                         ,(addr>>24)&0xff
  92                                         ,(addr>>16)&0xff
  93                                         ,(addr>>8)&0xff
  94                                         ,addr&0xff
  95                                         ,(mask>>24)&0xff
  96                                         ,(mask>>16)&0xff
  97                                         ,(mask>>8)&0xff
  98                                         ,mask&0xff);
  99                                 ifr++;
 100                         }
 101                 }
 102                 free(ifc.ifc_buf);
 103         }
 104         return ret;
 105 }
 106
 107 int main (int UNUSED argc, char UNUSED *argv[])
 108 {
 109         devlist_read2_2();
 110         return 0;
 111 }
 112