From 0f6364ac757bbdd02fe0e1577edebc2bd6198221 Mon Sep 17 00:00:00 2001
From: Mark Wooding <mdw@distorted.org.uk>
Date: Sun, 10 Jul 2011 21:49:44 +0100
Subject: [PATCH] functions.m4: Set IPv6 options in setopt and setdevopt.

Also allow selection of interfaces in setdevopt.  We don't need this
yet, but it will allow selective enabling of reverse-path filtering and
similar should that turn out to be useful.
---
 functions.m4 | 45 ++++++++++++++++++++++++++++++++++++++-------
 1 file changed, 38 insertions(+), 7 deletions(-)

diff --git a/functions.m4 b/functions.m4
index ca4519e..c0cd0b3 100644
--- a/functions.m4
+++ b/functions.m4
@@ -108,19 +108,50 @@ m4_divert(24)m4_dnl
 ## Set an IP sysctl.
 setopt () {
   set -e
-  opt=$1; shift; val=$*
-  run sysctl -q net/ipv4/$opt="$val"
+  opt=$1 val=$2
+  any=nil
+  for ver in ipv4 ipv6; do
+    if [ -f /proc/sys/net/$ver/$opt ]; then
+      run sysctl -q net/$ver/$opt="$val"
+      any=t
+    fi
+  done
+  case $any in
+    nil) echo >&2 "$0: unknown IP option $opt"; exit 1 ;;
+  esac
 }
 
-## setdevopt OPTION VALUE
+## setdevopt OPTION VALUE [INTERFACES ...]
 ##
 ## Set an IP interface-level sysctl.
 setdevopt () {
   set -e
-  opt=$1; shift; val=$*
-  for i in /proc/sys/net/ipv4/conf/*; do
-    [ -f $i/$opt ] &&
-      run sysctl -q net/ipv4/conf/${i#/proc/sys/net/ipv4/conf/}/$opt="$val"
+  opt=$1 val=$2; shift 2
+  case "$#,$1" in
+    0, | 1,all)
+      set -- $(
+	seen=:
+	for ver in ipv4 ipv6; do
+	  cd /proc/sys/net/$ver/conf
+	  for i in *; do
+	    [ -f $i/$opt ] || continue
+	    case "$seen" in (*:$i:*) continue ;; esac
+	    echo $i
+	  done
+	done)
+      ;;
+  esac
+  for i in "$@"; do
+    any=nil
+    for ver in ipv4 ipv6; do
+      if [ -f /proc/sys/net/$ver/conf/$i/$opt ]; then
+	any=t
+	run sysctl -q net/ipv4/conf/$i/$opt="$val"
+      fi
+    done
+    case $any in
+      nil) echo >&2 "$0: unknown device option $opt"; exit 1 ;;
+    esac
   done
 }
 
-- 
2.11.0