zebra/ipforward_proc.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Fetch ipforward value by reading /proc filesystem.
   4  * Copyright (C) 1997 Kunihiro Ishiguro
   5  */
   6
   7 #include <zebra.h>
   8
   9 #ifdef GNU_LINUX
  10
  11 #include "log.h"
  12 #include "privs.h"
  13
  14 #include "zebra/ipforward.h"
  15
  16 extern struct zebra_privs_t zserv_privs;
  17
  18 static const char proc_net_snmp[] = "/proc/net/snmp";
  19
  20 static void dropline(FILE *fp)
  21 {
  22         while (getc(fp) != '\n')
  23                 ;
  24 }
  25
  26 int ipforward(void)
  27 {
  28         int ret = 0;
  29         FILE *fp;
  30         int ipforwarding = 0;
  31         char buf[10];
  32
  33         fp = fopen(proc_net_snmp, "r");
  34
  35         if (fp == NULL)
  36                 return -1;
  37
  38         /* We don't care about the first line. */
  39         dropline(fp);
  40
  41         /* Get ip_statistics.IpForwarding :
  42            1 => ip forwarding enabled
  43            2 => ip forwarding off. */
  44         if (fgets(buf, 6, fp))
  45                 ret = sscanf(buf, "Ip: %d", &ipforwarding);
  46
  47         fclose(fp);
  48
  49         if (ret == 1 && ipforwarding == 1)
  50                 return 1;
  51
  52         return 0;
  53 }
  54
  55 /* char proc_ipv4_forwarding[] = "/proc/sys/net/ipv4/conf/all/forwarding"; */
  56 static const char proc_ipv4_forwarding[] = "/proc/sys/net/ipv4/ip_forward";
  57
  58 int ipforward_on(void)
  59 {
  60         FILE *fp;
  61
  62         frr_with_privs(&zserv_privs) {
  63
  64                 fp = fopen(proc_ipv4_forwarding, "w");
  65
  66                 if (fp == NULL) {
  67                         return -1;
  68                 }
  69
  70                 fprintf(fp, "1\n");
  71
  72                 fclose(fp);
  73
  74         }
  75
  76         return ipforward();
  77 }
  78
  79 int ipforward_off(void)
  80 {
  81         FILE *fp;
  82
  83         frr_with_privs(&zserv_privs) {
  84
  85                 fp = fopen(proc_ipv4_forwarding, "w");
  86
  87                 if (fp == NULL) {
  88                         return -1;
  89                 }
  90
  91                 fprintf(fp, "0\n");
  92
  93                 fclose(fp);
  94
  95         }
  96
  97         return ipforward();
  98 }
  99
 100 static const char proc_ipv6_forwarding[] =
 101         "/proc/sys/net/ipv6/conf/all/forwarding";
 102
 103 int ipforward_ipv6(void)
 104 {
 105         int ret = 0;
 106         FILE *fp;
 107         char buf[5];
 108         int ipforwarding = 0;
 109
 110         fp = fopen(proc_ipv6_forwarding, "r");
 111
 112         if (fp == NULL)
 113                 return -1;
 114
 115         if (fgets(buf, 2, fp))
 116                 ret = sscanf(buf, "%d", &ipforwarding);
 117
 118         fclose(fp);
 119
 120         if (ret != 1)
 121                 return 0;
 122
 123         return ipforwarding;
 124 }
 125
 126 int ipforward_ipv6_on(void)
 127 {
 128         FILE *fp;
 129
 130         frr_with_privs(&zserv_privs) {
 131
 132                 fp = fopen(proc_ipv6_forwarding, "w");
 133
 134                 if (fp == NULL) {
 135                         return -1;
 136                 }
 137
 138                 fprintf(fp, "1\n");
 139
 140                 fclose(fp);
 141
 142         }
 143
 144         return ipforward_ipv6();
 145 }
 146
 147
 148 int ipforward_ipv6_off(void)
 149 {
 150         FILE *fp;
 151
 152         frr_with_privs(&zserv_privs) {
 153
 154                 fp = fopen(proc_ipv6_forwarding, "w");
 155
 156                 if (fp == NULL) {
 157                         return -1;
 158                 }
 159
 160                 fprintf(fp, "0\n");
 161
 162                 fclose(fp);
 163
 164         }
 165
 166         return ipforward_ipv6();
 167 }
 168
 169 #endif /* GNU_LINUX */