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 #include "zebra/ipforward.h"
  29
  30 extern struct zebra_privs_t zserv_privs;
  31
  32 char proc_net_snmp[] = "/proc/net/snmp";
  33
  34 static void
  35 dropline (FILE *fp)
  36 {
  37   int c;
  38
  39   while ((c = getc (fp)) != '\n')
  40     ;
  41 }
  42
  43 int
  44 ipforward (void)
  45 {
  46   FILE *fp;
  47   int ipforwarding = 0;
  48   char buf[10];
  49
  50   fp = fopen (proc_net_snmp, "r");
  51
  52   if (fp == NULL)
  53     return -1;
  54
  55   /* We don't care about the first line. */
  56   dropline (fp);
  57
  58   /* Get ip_statistics.IpForwarding :
  59      1 => ip forwarding enabled
  60      2 => ip forwarding off. */
  61   if (fgets (buf, 6, fp))
  62     sscanf (buf, "Ip: %d", &ipforwarding);
  63
  64   fclose(fp);
  65
  66   if (ipforwarding == 1)
  67     return 1;
  68
  69   return 0;
  70 }
  71
  72 /* char proc_ipv4_forwarding[] = "/proc/sys/net/ipv4/conf/all/forwarding"; */
  73 char proc_ipv4_forwarding[] = "/proc/sys/net/ipv4/ip_forward";
  74
  75 int
  76 ipforward_on (void)
  77 {
  78   FILE *fp;
  79
  80   if ( zserv_privs.change(ZPRIVS_RAISE) )
  81         zlog_err ("Can't raise privileges, %s", safe_strerror (errno) );
  82
  83   fp = fopen (proc_ipv4_forwarding, "w");
  84
  85   if (fp == NULL) {
  86     if ( zserv_privs.change(ZPRIVS_LOWER) )
  87       zlog_err ("Can't lower privileges, %s", safe_strerror (errno));
  88     return -1;
  89   }
  90
  91   fprintf (fp, "1\n");
  92
  93   fclose (fp);
  94
  95   if ( zserv_privs.change(ZPRIVS_LOWER) )
  96     zlog_err ("Can't lower privileges, %s", safe_strerror (errno));
  97
  98   return ipforward ();
  99 }
 100
 101 int
 102 ipforward_off (void)
 103 {
 104   FILE *fp;
 105
 106   if ( zserv_privs.change(ZPRIVS_RAISE) )
 107         zlog_err ("Can't raise privileges, %s", safe_strerror (errno));
 108
 109   fp = fopen (proc_ipv4_forwarding, "w");
 110
 111   if (fp == NULL) {
 112     if ( zserv_privs.change(ZPRIVS_LOWER) )
 113       zlog_err ("Can't lower privileges, %s", safe_strerror (errno));
 114     return -1;
 115   }
 116
 117   fprintf (fp, "0\n");
 118
 119   fclose (fp);
 120
 121   if ( zserv_privs.change(ZPRIVS_LOWER) )
 122     zlog_err ("Can't lower privileges, %s", safe_strerror (errno));
 123
 124   return ipforward ();
 125 }
 126
 127 char proc_ipv6_forwarding[] = "/proc/sys/net/ipv6/conf/all/forwarding";
 128
 129 int
 130 ipforward_ipv6 (void)
 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   if (fgets (buf, 2, fp))
 142     sscanf (buf, "%d", &ipforwarding);
 143
 144   fclose (fp);
 145   return ipforwarding;
 146 }
 147
 148 int
 149 ipforward_ipv6_on (void)
 150 {
 151   FILE *fp;
 152
 153   if ( zserv_privs.change(ZPRIVS_RAISE) )
 154        zlog_err ("Can't raise privileges, %s", safe_strerror (errno));
 155
 156   fp = fopen (proc_ipv6_forwarding, "w");
 157
 158   if (fp == NULL) {
 159     if ( zserv_privs.change(ZPRIVS_LOWER) )
 160       zlog_err ("Can't lower privileges, %s", safe_strerror (errno));
 161     return -1;
 162   }
 163
 164   fprintf (fp, "1\n");
 165
 166   fclose (fp);
 167
 168   if ( zserv_privs.change(ZPRIVS_LOWER) )
 169     zlog_err ("Can't lower privileges, %s", safe_strerror (errno));
 170
 171   return ipforward_ipv6 ();
 172 }
 173
 174
 175 int
 176 ipforward_ipv6_off (void)
 177 {
 178   FILE *fp;
 179
 180   if ( zserv_privs.change(ZPRIVS_RAISE) )
 181        zlog_err ("Can't raise privileges, %s", safe_strerror (errno));
 182
 183   fp = fopen (proc_ipv6_forwarding, "w");
 184
 185   if (fp == NULL) {
 186     if ( zserv_privs.change(ZPRIVS_LOWER) )
 187       zlog_err ("Can't lower privileges, %s", safe_strerror (errno));
 188     return -1;
 189   }
 190
 191   fprintf (fp, "0\n");
 192
 193   fclose (fp);
 194
 195   if ( zserv_privs.change(ZPRIVS_LOWER) )
 196     zlog_err ("Can't lower privileges, %s", safe_strerror (errno));
 197
 198   return ipforward_ipv6 ();
 199 }