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 #ifdef GNU_LINUX
  25
  26 #include "log.h"
  27 #include "privs.h"
  28
  29 #include "zebra/ipforward.h"
  30
  31 extern struct zebra_privs_t zserv_privs;
  32
  33 char proc_net_snmp[] = "/proc/net/snmp";
  34
  35 static void dropline(FILE *fp)
  36 {
  37         int c;
  38
  39         while ((c = getc(fp)) != '\n')
  40                 ;
  41 }
  42
  43 int ipforward(void)
  44 {
  45         int ret = 0;
  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                 ret = sscanf(buf, "Ip: %d", &ipforwarding);
  63
  64         fclose(fp);
  65
  66         if (ret == 1 && 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 ipforward_on(void)
  76 {
  77         FILE *fp;
  78
  79         frr_elevate_privs(&zserv_privs) {
  80
  81                 fp = fopen(proc_ipv4_forwarding, "w");
  82
  83                 if (fp == NULL) {
  84                         return -1;
  85                 }
  86
  87                 fprintf(fp, "1\n");
  88
  89                 fclose(fp);
  90
  91         }
  92
  93         return ipforward();
  94 }
  95
  96 int ipforward_off(void)
  97 {
  98         FILE *fp;
  99
 100         frr_elevate_privs(&zserv_privs) {
 101
 102                 fp = fopen(proc_ipv4_forwarding, "w");
 103
 104                 if (fp == NULL) {
 105                         return -1;
 106                 }
 107
 108                 fprintf(fp, "0\n");
 109
 110                 fclose(fp);
 111
 112         }
 113
 114         return ipforward();
 115 }
 116
 117 char proc_ipv6_forwarding[] = "/proc/sys/net/ipv6/conf/all/forwarding";
 118
 119 int ipforward_ipv6(void)
 120 {
 121         int ret = 0;
 122         FILE *fp;
 123         char buf[5];
 124         int ipforwarding = 0;
 125
 126         fp = fopen(proc_ipv6_forwarding, "r");
 127
 128         if (fp == NULL)
 129                 return -1;
 130
 131         if (fgets(buf, 2, fp))
 132                 ret = sscanf(buf, "%d", &ipforwarding);
 133
 134         fclose(fp);
 135
 136         if (ret != 1)
 137                 return 0;
 138
 139         return ipforwarding;
 140 }
 141
 142 int ipforward_ipv6_on(void)
 143 {
 144         FILE *fp;
 145
 146         frr_elevate_privs(&zserv_privs) {
 147
 148                 fp = fopen(proc_ipv6_forwarding, "w");
 149
 150                 if (fp == NULL) {
 151                         return -1;
 152                 }
 153
 154                 fprintf(fp, "1\n");
 155
 156                 fclose(fp);
 157
 158         }
 159
 160         return ipforward_ipv6();
 161 }
 162
 163
 164 int ipforward_ipv6_off(void)
 165 {
 166         FILE *fp;
 167
 168         frr_elevate_privs(&zserv_privs) {
 169
 170                 fp = fopen(proc_ipv6_forwarding, "w");
 171
 172                 if (fp == NULL) {
 173                         return -1;
 174                 }
 175
 176                 fprintf(fp, "0\n");
 177
 178                 fclose(fp);
 179
 180         }
 181
 182         return ipforward_ipv6();
 183 }
 184
 185 #endif /* GNU_LINUX */