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 #include "lib_errors.h"
  29
  30 #include "zebra/ipforward.h"
  31
  32 extern struct zebra_privs_t zserv_privs;
  33
  34 char proc_net_snmp[] = "/proc/net/snmp";
  35
  36 static void dropline(FILE *fp)
  37 {
  38         int c;
  39
  40         while ((c = getc(fp)) != '\n')
  41                 ;
  42 }
  43
  44 int ipforward(void)
  45 {
  46         int ret = 0;
  47         FILE *fp;
  48         int ipforwarding = 0;
  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         if (fgets(buf, 6, fp))
  63                 ret = sscanf(buf, "Ip: %d", &ipforwarding);
  64
  65         fclose(fp);
  66
  67         if (ret == 1 && 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 ipforward_on(void)
  77 {
  78         FILE *fp;
  79
  80         frr_elevate_privs(&zserv_privs) {
  81
  82                 fp = fopen(proc_ipv4_forwarding, "w");
  83
  84                 if (fp == NULL) {
  85                         return -1;
  86                 }
  87
  88                 fprintf(fp, "1\n");
  89
  90                 fclose(fp);
  91
  92         }
  93
  94         return ipforward();
  95 }
  96
  97 int ipforward_off(void)
  98 {
  99         FILE *fp;
 100
 101         frr_elevate_privs(&zserv_privs) {
 102
 103                 fp = fopen(proc_ipv4_forwarding, "w");
 104
 105                 if (fp == NULL) {
 106                         return -1;
 107                 }
 108
 109                 fprintf(fp, "0\n");
 110
 111                 fclose(fp);
 112
 113         }
 114
 115         return ipforward();
 116 }
 117
 118 char proc_ipv6_forwarding[] = "/proc/sys/net/ipv6/conf/all/forwarding";
 119
 120 int ipforward_ipv6(void)
 121 {
 122         int ret = 0;
 123         FILE *fp;
 124         char buf[5];
 125         int ipforwarding = 0;
 126
 127         fp = fopen(proc_ipv6_forwarding, "r");
 128
 129         if (fp == NULL)
 130                 return -1;
 131
 132         if (fgets(buf, 2, fp))
 133                 ret = sscanf(buf, "%d", &ipforwarding);
 134
 135         fclose(fp);
 136
 137         if (ret != 1)
 138                 return 0;
 139
 140         return ipforwarding;
 141 }
 142
 143 int ipforward_ipv6_on(void)
 144 {
 145         FILE *fp;
 146
 147         frr_elevate_privs(&zserv_privs) {
 148
 149                 fp = fopen(proc_ipv6_forwarding, "w");
 150
 151                 if (fp == NULL) {
 152                         return -1;
 153                 }
 154
 155                 fprintf(fp, "1\n");
 156
 157                 fclose(fp);
 158
 159         }
 160
 161         return ipforward_ipv6();
 162 }
 163
 164
 165 int ipforward_ipv6_off(void)
 166 {
 167         FILE *fp;
 168
 169         frr_elevate_privs(&zserv_privs) {
 170
 171                 fp = fopen(proc_ipv6_forwarding, "w");
 172
 173                 if (fp == NULL) {
 174                         return -1;
 175                 }
 176
 177                 fprintf(fp, "0\n");
 178
 179                 fclose(fp);
 180
 181         }
 182
 183         return ipforward_ipv6();
 184 }
 185
 186 #endif /* GNU_LINUX */