zebra/ipforward_proc.c

   1 /*
   2  * Fetch ipforward value by reading /proc filesystem.
   3  * Copyright (C) 1997 Kunihiro Ishiguro
   4  *
   5  * This file is part of GNU Zebra.
   6  *
   7  * GNU Zebra is free software; you can redistribute it and/or modify it
   8  * under the terms of the GNU General Public License as published by the
   9  * Free Software Foundation; either version 2, or (at your option) any
  10  * later version.
  11  *
  12  * GNU Zebra is distributed in the hope that it will be useful, but
  13  * WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  * General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with GNU Zebra; see the file COPYING.  If not, write to the Free
  19  * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
  20  * 02111-1307, USA.
  21  */
  22
  23 #include <zebra.h>
  24
  25 #include "log.h"
  26 #include "privs.h"
  27
  28 extern struct zebra_privs_t zserv_privs;
  29
  30 char proc_net_snmp[] = "/proc/net/snmp";
  31
  32 static void
  33 dropline (FILE *fp)
  34 {
  35   int c;
  36
  37   while ((c = getc (fp)) != '\n')
  38     ;
  39 }
  40
  41 int
  42 ipforward ()
  43 {
  44   FILE *fp;
  45   int ipforwarding = 0;
  46   char *pnt;
  47   char buf[10];
  48
  49   fp = fopen (proc_net_snmp, "r");
  50
  51   if (fp == NULL)
  52     return -1;
  53
  54   /* We don't care about the first line. */
  55   dropline (fp);
  56
  57   /* Get ip_statistics.IpForwarding :
  58      1 => ip forwarding enabled
  59      2 => ip forwarding off. */
  60   pnt = fgets (buf, 6, fp);
  61   sscanf (buf, "Ip: %d", &ipforwarding);
  62
  63   fclose(fp);
  64
  65   if (ipforwarding == 1)
  66     return 1;
  67
  68   return 0;
  69 }
  70
  71 /* char proc_ipv4_forwarding[] = "/proc/sys/net/ipv4/conf/all/forwarding"; */
  72 char proc_ipv4_forwarding[] = "/proc/sys/net/ipv4/ip_forward";
  73
  74 int
  75 ipforward_on ()
  76 {
  77   FILE *fp;
  78
  79   if ( zserv_privs.change(ZPRIVS_RAISE) )
  80         zlog_err ("Can't raise privileges, %s", safe_strerror (errno) );
  81
  82   fp = fopen (proc_ipv4_forwarding, "w");
  83
  84   if (fp == NULL) {
  85     if ( zserv_privs.change(ZPRIVS_LOWER) )
  86       zlog_err ("Can't lower privileges, %s", safe_strerror (errno));
  87     return -1;
  88   }
  89
  90   fprintf (fp, "1\n");
  91
  92   fclose (fp);
  93
  94   if ( zserv_privs.change(ZPRIVS_LOWER) )
  95     zlog_err ("Can't lower privileges, %s", safe_strerror (errno));
  96
  97   return ipforward ();
  98 }
  99
 100 int
 101 ipforward_off ()
 102 {
 103   FILE *fp;
 104
 105   if ( zserv_privs.change(ZPRIVS_RAISE) )
 106         zlog_err ("Can't raise privileges, %s", safe_strerror (errno));
 107
 108   fp = fopen (proc_ipv4_forwarding, "w");
 109
 110   if (fp == NULL) {
 111     if ( zserv_privs.change(ZPRIVS_LOWER) )
 112       zlog_err ("Can't lower privileges, %s", safe_strerror (errno));
 113     return -1;
 114   }
 115
 116   fprintf (fp, "0\n");
 117
 118   fclose (fp);
 119
 120   if ( zserv_privs.change(ZPRIVS_LOWER) )
 121     zlog_err ("Can't lower privileges, %s", safe_strerror (errno));
 122
 123   return ipforward ();
 124 }
 125 #ifdef HAVE_IPV6
 126
 127 char proc_ipv6_forwarding[] = "/proc/sys/net/ipv6/conf/all/forwarding";
 128
 129 int
 130 ipforward_ipv6 ()
 131 {
 132   FILE *fp;
 133   char buf[5];
 134   int ipforwarding = 0;
 135
 136   fp = fopen (proc_ipv6_forwarding, "r");
 137
 138   if (fp == NULL)
 139     return -1;
 140
 141   fgets (buf, 2, fp);
 142   sscanf (buf, "%d", &ipforwarding);
 143
 144   return ipforwarding;
 145 }
 146
 147 int
 148 ipforward_ipv6_on ()
 149 {
 150   FILE *fp;
 151
 152   if ( zserv_privs.change(ZPRIVS_RAISE) )
 153         zlog_err ("Can't raise privileges, %s", safe_strerror (errno));
 154
 155   fp = fopen (proc_ipv6_forwarding, "w");
 156
 157   if (fp == NULL) {
 158     if ( zserv_privs.change(ZPRIVS_LOWER) )
 159       zlog_err ("Can't lower privileges, %s", safe_strerror (errno));
 160     return -1;
 161   }
 162
 163   fprintf (fp, "1\n");
 164
 165   fclose (fp);
 166
 167   if ( zserv_privs.change(ZPRIVS_LOWER) )
 168     zlog_err ("Can't lower privileges, %s", safe_strerror (errno));
 169
 170   return ipforward_ipv6 ();
 171 }
 172
 173 int
 174 ipforward_ipv6_off ()
 175 {
 176   FILE *fp;
 177
 178   if ( zserv_privs.change(ZPRIVS_RAISE) )
 179         zlog_err ("Can't raise privileges, %s", safe_strerror (errno));
 180
 181   fp = fopen (proc_ipv6_forwarding, "w");
 182
 183   if (fp == NULL) {
 184     if ( zserv_privs.change(ZPRIVS_LOWER) )
 185       zlog_err ("Can't lower privileges, %s", safe_strerror (errno));
 186     return -1;
 187   }
 188
 189   fprintf (fp, "0\n");
 190
 191   fclose (fp);
 192
 193   if ( zserv_privs.change(ZPRIVS_LOWER) )
 194     zlog_err ("Can't lower privileges, %s", safe_strerror (errno));
 195
 196   return ipforward_ipv6 ();
 197 }
 198 #endif /* HAVE_IPV6 */