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 along
  18  * with this program; see the file COPYING; if not, write to the Free Software
  19  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
  20  */
  21
  22 #include <zebra.h>
  23
  24 #include "log.h"
  25 #include "privs.h"
  26
  27 #include "zebra/ipforward.h"
  28
  29 extern struct zebra_privs_t zserv_privs;
  30
  31 char proc_net_snmp[] = "/proc/net/snmp";
  32
  33 static void
  34 dropline (FILE *fp)
  35 {
  36   int c;
  37
  38   while ((c = getc (fp)) != '\n')
  39     ;
  40 }
  41
  42 int
  43 ipforward (void)
  44 {
  45   FILE *fp;
  46   int ipforwarding = 0;
  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   if (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 (void)
  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 (void)
 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
 126 char proc_ipv6_forwarding[] = "/proc/sys/net/ipv6/conf/all/forwarding";
 127
 128 int
 129 ipforward_ipv6 (void)
 130 {
 131   FILE *fp;
 132   char buf[5];
 133   int ipforwarding = 0;
 134
 135   fp = fopen (proc_ipv6_forwarding, "r");
 136
 137   if (fp == NULL)
 138     return -1;
 139
 140   if (fgets (buf, 2, fp))
 141     sscanf (buf, "%d", &ipforwarding);
 142
 143   fclose (fp);
 144   return ipforwarding;
 145 }
 146
 147 int
 148 ipforward_ipv6_on (void)
 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
 174 int
 175 ipforward_ipv6_off (void)
 176 {
 177   FILE *fp;
 178
 179   if ( zserv_privs.change(ZPRIVS_RAISE) )
 180        zlog_err ("Can't raise privileges, %s", safe_strerror (errno));
 181
 182   fp = fopen (proc_ipv6_forwarding, "w");
 183
 184   if (fp == NULL) {
 185     if ( zserv_privs.change(ZPRIVS_LOWER) )
 186       zlog_err ("Can't lower privileges, %s", safe_strerror (errno));
 187     return -1;
 188   }
 189
 190   fprintf (fp, "0\n");
 191
 192   fclose (fp);
 193
 194   if ( zserv_privs.change(ZPRIVS_LOWER) )
 195     zlog_err ("Can't lower privileges, %s", safe_strerror (errno));
 196
 197   return ipforward_ipv6 ();
 198 }