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         FILE *fp;
  46         int ipforwarding = 0;
  47         char buf[10];
  48
  49         fp = fopen(proc_net_snmp, "r");
  50
  51         if (fp == NULL)
  52                 return -1;
  53
  54         /* We don't care about the first line. */
  55         dropline(fp);
  56
  57         /* Get ip_statistics.IpForwarding :
  58            1 => ip forwarding enabled
  59            2 => ip forwarding off. */
  60         if (fgets(buf, 6, fp))
  61                 sscanf(buf, "Ip: %d", &ipforwarding);
  62
  63         fclose(fp);
  64
  65         if (ipforwarding == 1)
  66                 return 1;
  67
  68         return 0;
  69 }
  70
  71 /* char proc_ipv4_forwarding[] = "/proc/sys/net/ipv4/conf/all/forwarding"; */
  72 char proc_ipv4_forwarding[] = "/proc/sys/net/ipv4/ip_forward";
  73
  74 int ipforward_on(void)
  75 {
  76         FILE *fp;
  77
  78         if (zserv_privs.change(ZPRIVS_RAISE))
  79                 zlog_err("Can't raise privileges, %s", safe_strerror(errno));
  80
  81         fp = fopen(proc_ipv4_forwarding, "w");
  82
  83         if (fp == NULL) {
  84                 if (zserv_privs.change(ZPRIVS_LOWER))
  85                         zlog_err("Can't lower privileges, %s",
  86                                  safe_strerror(errno));
  87                 return -1;
  88         }
  89
  90         fprintf(fp, "1\n");
  91
  92         fclose(fp);
  93
  94         if (zserv_privs.change(ZPRIVS_LOWER))
  95                 zlog_err("Can't lower privileges, %s", safe_strerror(errno));
  96
  97         return ipforward();
  98 }
  99
 100 int ipforward_off(void)
 101 {
 102         FILE *fp;
 103
 104         if (zserv_privs.change(ZPRIVS_RAISE))
 105                 zlog_err("Can't raise privileges, %s", safe_strerror(errno));
 106
 107         fp = fopen(proc_ipv4_forwarding, "w");
 108
 109         if (fp == NULL) {
 110                 if (zserv_privs.change(ZPRIVS_LOWER))
 111                         zlog_err("Can't lower privileges, %s",
 112                                  safe_strerror(errno));
 113                 return -1;
 114         }
 115
 116         fprintf(fp, "0\n");
 117
 118         fclose(fp);
 119
 120         if (zserv_privs.change(ZPRIVS_LOWER))
 121                 zlog_err("Can't lower privileges, %s", safe_strerror(errno));
 122
 123         return ipforward();
 124 }
 125
 126 char proc_ipv6_forwarding[] = "/proc/sys/net/ipv6/conf/all/forwarding";
 127
 128 int ipforward_ipv6(void)
 129 {
 130         FILE *fp;
 131         char buf[5];
 132         int ipforwarding = 0;
 133
 134         fp = fopen(proc_ipv6_forwarding, "r");
 135
 136         if (fp == NULL)
 137                 return -1;
 138
 139         if (fgets(buf, 2, fp))
 140                 sscanf(buf, "%d", &ipforwarding);
 141
 142         fclose(fp);
 143         return ipforwarding;
 144 }
 145
 146 int ipforward_ipv6_on(void)
 147 {
 148         FILE *fp;
 149
 150         if (zserv_privs.change(ZPRIVS_RAISE))
 151                 zlog_err("Can't raise privileges, %s", safe_strerror(errno));
 152
 153         fp = fopen(proc_ipv6_forwarding, "w");
 154
 155         if (fp == NULL) {
 156                 if (zserv_privs.change(ZPRIVS_LOWER))
 157                         zlog_err("Can't lower privileges, %s",
 158                                  safe_strerror(errno));
 159                 return -1;
 160         }
 161
 162         fprintf(fp, "1\n");
 163
 164         fclose(fp);
 165
 166         if (zserv_privs.change(ZPRIVS_LOWER))
 167                 zlog_err("Can't lower privileges, %s", safe_strerror(errno));
 168
 169         return ipforward_ipv6();
 170 }
 171
 172
 173 int ipforward_ipv6_off(void)
 174 {
 175         FILE *fp;
 176
 177         if (zserv_privs.change(ZPRIVS_RAISE))
 178                 zlog_err("Can't raise privileges, %s", safe_strerror(errno));
 179
 180         fp = fopen(proc_ipv6_forwarding, "w");
 181
 182         if (fp == NULL) {
 183                 if (zserv_privs.change(ZPRIVS_LOWER))
 184                         zlog_err("Can't lower privileges, %s",
 185                                  safe_strerror(errno));
 186                 return -1;
 187         }
 188
 189         fprintf(fp, "0\n");
 190
 191         fclose(fp);
 192
 193         if (zserv_privs.change(ZPRIVS_LOWER))
 194                 zlog_err("Can't lower privileges, %s", safe_strerror(errno));
 195
 196         return ipforward_ipv6();
 197 }
 198
 199 #endif /* GNU_LINUX */