From a430e8e22b401c6a27e0e45cd6f84bb94741574e Mon Sep 17 00:00:00 2001
From: Willy Tarreau <w@1wt.eu>
Date: Wed, 14 Mar 2018 19:20:30 +0100
Subject: scripts/ipforward: better test for ipv4/ipv6 sysctls

If ipv6 is disabled, the ipforward script may fail and/or show errors.
Better test that entries exist before touching them.
---
 sbin/init.d/ipforward | 22 ++++++++++++++++------
 1 file changed, 16 insertions(+), 6 deletions(-)

diff --git a/sbin/init.d/ipforward b/sbin/init.d/ipforward
index 478d0fb..7fed9a7 100644
--- a/sbin/init.d/ipforward
+++ b/sbin/init.d/ipforward
@@ -30,16 +30,26 @@ function is_loaded {
 
 # Enables ip forwarding. Returns 0 on success.
 function enable_forwarding {
-    echo 1 > /proc/sys/net/ipv4/ip_forward 2>/dev/null
-    [ $? -ne 0 ] && return $?
-    echo 1 > /proc/sys/net/ipv6/conf/all/forwarding 2>/dev/null
+    if [ -e /proc/sys/net/ipv4/ip_forward ]; then
+        echo 1 > /proc/sys/net/ipv4/ip_forward
+        [ $? -eq 0 ] || return $?
+    fi
+    if [ -e /proc/sys/net/ipv6/conf/all/forwarding ]; then
+        echo 1 > /proc/sys/net/ipv6/conf/all/forwarding
+        [ $? -eq 0 ] || return $?
+    fi
 }
 
 # Disables ip forwarding. Returns 0 on success.
 function disable_forwarding {
-    echo 0 > /proc/sys/net/ipv4/ip_forward 2>/dev/null
-    [ $? -ne 0 ] && return $?
-    echo 0 > /proc/sys/net/ipv6/conf/all/forwarding 2>/dev/null
+    if [ -e /proc/sys/net/ipv4/ip_forward ]; then
+        echo 0 > /proc/sys/net/ipv4/ip_forward
+        [ $? -eq 0 ] || return $?
+    fi
+    if [ -e /proc/sys/net/ipv6/conf/all/forwarding ]; then
+        echo 0 > /proc/sys/net/ipv6/conf/all/forwarding
+        [ $? -eq 0 ] || return $?
+    fi
 }
 
 # checks wether the firewall modules are loaded
-- 
2.8.0.rc2.1.gbe9624a