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 *pnt;
  49   char buf[10];
  50
  51   fp = fopen (proc_net_snmp, "r");
  52
  53   if (fp == NULL)
  54     return -1;
  55
  56   /* We don't care about the first line. */
  57   dropline (fp);
  58
  59   /* Get ip_statistics.IpForwarding :
  60      1 => ip forwarding enabled
  61      2 => ip forwarding off. */
  62   pnt = fgets (buf, 6, fp);
  63   sscanf (buf, "Ip: %d", &ipforwarding);
  64
  65   fclose(fp);
  66
  67   if (ipforwarding == 1)
  68     return 1;
  69
  70   return 0;
  71 }
  72
  73 /* char proc_ipv4_forwarding[] = "/proc/sys/net/ipv4/conf/all/forwarding"; */
  74 char proc_ipv4_forwarding[] = "/proc/sys/net/ipv4/ip_forward";
  75
  76 int
  77 ipforward_on (void)
  78 {
  79   FILE *fp;
  80
  81   if ( zserv_privs.change(ZPRIVS_RAISE) )
  82         zlog_err ("Can't raise privileges, %s", safe_strerror (errno) );
  83
  84   fp = fopen (proc_ipv4_forwarding, "w");
  85
  86   if (fp == NULL) {
  87     if ( zserv_privs.change(ZPRIVS_LOWER) )
  88       zlog_err ("Can't lower privileges, %s", safe_strerror (errno));
  89     return -1;
  90   }
  91
  92   fprintf (fp, "1\n");
  93
  94   fclose (fp);
  95
  96   if ( zserv_privs.change(ZPRIVS_LOWER) )
  97     zlog_err ("Can't lower privileges, %s", safe_strerror (errno));
  98
  99   return ipforward ();
 100 }
 101
 102 int
 103 ipforward_off (void)
 104 {
 105   FILE *fp;
 106
 107   if ( zserv_privs.change(ZPRIVS_RAISE) )
 108         zlog_err ("Can't raise privileges, %s", safe_strerror (errno));
 109
 110   fp = fopen (proc_ipv4_forwarding, "w");
 111
 112   if (fp == NULL) {
 113     if ( zserv_privs.change(ZPRIVS_LOWER) )
 114       zlog_err ("Can't lower privileges, %s", safe_strerror (errno));
 115     return -1;
 116   }
 117
 118   fprintf (fp, "0\n");
 119
 120   fclose (fp);
 121
 122   if ( zserv_privs.change(ZPRIVS_LOWER) )
 123     zlog_err ("Can't lower privileges, %s", safe_strerror (errno));
 124
 125   return ipforward ();
 126 }
 127 #ifdef HAVE_IPV6
 128
 129 char proc_ipv6_forwarding[] = "/proc/sys/net/ipv6/conf/all/forwarding";
 130
 131 int
 132 ipforward_ipv6 (void)
 133 {
 134   FILE *fp;
 135   char buf[5];
 136   int ipforwarding = 0;
 137
 138   fp = fopen (proc_ipv6_forwarding, "r");
 139
 140   if (fp == NULL)
 141     return -1;
 142
 143   fgets (buf, 2, fp);
 144   sscanf (buf, "%d", &ipforwarding);
 145
 146   fclose (fp);
 147   return ipforwarding;
 148 }
 149
 150 int
 151 ipforward_ipv6_on (void)
 152 {
 153   FILE *fp;
 154
 155   if ( zserv_privs.change(ZPRIVS_RAISE) )
 156         zlog_err ("Can't raise privileges, %s", safe_strerror (errno));
 157
 158   fp = fopen (proc_ipv6_forwarding, "w");
 159
 160   if (fp == NULL) {
 161     if ( zserv_privs.change(ZPRIVS_LOWER) )
 162       zlog_err ("Can't lower privileges, %s", safe_strerror (errno));
 163     return -1;
 164   }
 165
 166   fprintf (fp, "1\n");
 167
 168   fclose (fp);
 169
 170   if ( zserv_privs.change(ZPRIVS_LOWER) )
 171     zlog_err ("Can't lower privileges, %s", safe_strerror (errno));
 172
 173   return ipforward_ipv6 ();
 174 }
 175
 176 int
 177 ipforward_ipv6_off (void)
 178 {
 179   FILE *fp;
 180
 181   if ( zserv_privs.change(ZPRIVS_RAISE) )
 182         zlog_err ("Can't raise privileges, %s", safe_strerror (errno));
 183
 184   fp = fopen (proc_ipv6_forwarding, "w");
 185
 186   if (fp == NULL) {
 187     if ( zserv_privs.change(ZPRIVS_LOWER) )
 188       zlog_err ("Can't lower privileges, %s", safe_strerror (errno));
 189     return -1;
 190   }
 191
 192   fprintf (fp, "0\n");
 193
 194   fclose (fp);
 195
 196   if ( zserv_privs.change(ZPRIVS_LOWER) )
 197     zlog_err ("Can't lower privileges, %s", safe_strerror (errno));
 198
 199   return ipforward_ipv6 ();
 200 }
 201 #endif /* HAVE_IPV6 */