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 static const char proc_net_snmp[] = "/proc/net/snmp";
  34
  35 static void dropline(FILE *fp)
  36 {
  37         while (getc(fp) != '\n')
  38                 ;
  39 }
  40
  41 int ipforward(void)
  42 {
  43         int ret = 0;
  44         FILE *fp;
  45         int ipforwarding = 0;
  46         char buf[10];
  47
  48         fp = fopen(proc_net_snmp, "r");
  49
  50         if (fp == NULL)
  51                 return -1;
  52
  53         /* We don't care about the first line. */
  54         dropline(fp);
  55
  56         /* Get ip_statistics.IpForwarding :
  57            1 => ip forwarding enabled
  58            2 => ip forwarding off. */
  59         if (fgets(buf, 6, fp))
  60                 ret = sscanf(buf, "Ip: %d", &ipforwarding);
  61
  62         fclose(fp);
  63
  64         if (ret == 1 && ipforwarding == 1)
  65                 return 1;
  66
  67         return 0;
  68 }
  69
  70 /* char proc_ipv4_forwarding[] = "/proc/sys/net/ipv4/conf/all/forwarding"; */
  71 static const char proc_ipv4_forwarding[] = "/proc/sys/net/ipv4/ip_forward";
  72
  73 int ipforward_on(void)
  74 {
  75         FILE *fp;
  76
  77         frr_with_privs(&zserv_privs) {
  78
  79                 fp = fopen(proc_ipv4_forwarding, "w");
  80
  81                 if (fp == NULL) {
  82                         return -1;
  83                 }
  84
  85                 fprintf(fp, "1\n");
  86
  87                 fclose(fp);
  88
  89         }
  90
  91         return ipforward();
  92 }
  93
  94 int ipforward_off(void)
  95 {
  96         FILE *fp;
  97
  98         frr_with_privs(&zserv_privs) {
  99
 100                 fp = fopen(proc_ipv4_forwarding, "w");
 101
 102                 if (fp == NULL) {
 103                         return -1;
 104                 }
 105
 106                 fprintf(fp, "0\n");
 107
 108                 fclose(fp);
 109
 110         }
 111
 112         return ipforward();
 113 }
 114
 115 static const char proc_ipv6_forwarding[] =
 116         "/proc/sys/net/ipv6/conf/all/forwarding";
 117
 118 int ipforward_ipv6(void)
 119 {
 120         int ret = 0;
 121         FILE *fp;
 122         char buf[5];
 123         int ipforwarding = 0;
 124
 125         fp = fopen(proc_ipv6_forwarding, "r");
 126
 127         if (fp == NULL)
 128                 return -1;
 129
 130         if (fgets(buf, 2, fp))
 131                 ret = sscanf(buf, "%d", &ipforwarding);
 132
 133         fclose(fp);
 134
 135         if (ret != 1)
 136                 return 0;
 137
 138         return ipforwarding;
 139 }
 140
 141 int ipforward_ipv6_on(void)
 142 {
 143         FILE *fp;
 144
 145         frr_with_privs(&zserv_privs) {
 146
 147                 fp = fopen(proc_ipv6_forwarding, "w");
 148
 149                 if (fp == NULL) {
 150                         return -1;
 151                 }
 152
 153                 fprintf(fp, "1\n");
 154
 155                 fclose(fp);
 156
 157         }
 158
 159         return ipforward_ipv6();
 160 }
 161
 162
 163 int ipforward_ipv6_off(void)
 164 {
 165         FILE *fp;
 166
 167         frr_with_privs(&zserv_privs) {
 168
 169                 fp = fopen(proc_ipv6_forwarding, "w");
 170
 171                 if (fp == NULL) {
 172                         return -1;
 173                 }
 174
 175                 fprintf(fp, "0\n");
 176
 177                 fclose(fp);
 178
 179         }
 180
 181         return ipforward_ipv6();
 182 }
 183
 184 #endif /* GNU_LINUX */