From e5450d5a1b84eabeec1376a4725435356a19a0d2 Mon Sep 17 00:00:00 2001
From: Jo-Philipp Wich <jow@openwrt.org>
Date: Sat, 4 Sep 2010 15:49:13 +0000
Subject: [package] firewall: 	- handle NAT reflection in firewall hotplug,
 solves synchronizing issues on boot 	- introduce masq_src and masq_dest
 options to limit zone masq to specific ip ranges, supports multiple subnets
 and negation

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@22888 3c298f89-4303-0410-b956-a3cf2f4a3e73
---
 package/firewall/files/lib/core_interface.sh | 32 +++++++++++++++++++++++-----
 1 file changed, 27 insertions(+), 5 deletions(-)

(limited to 'package/firewall/files/lib/core_interface.sh')

diff --git a/package/firewall/files/lib/core_interface.sh b/package/firewall/files/lib/core_interface.sh
index 69ddc343aa..c2a5bd7f33 100644
--- a/package/firewall/files/lib/core_interface.sh
+++ b/package/firewall/files/lib/core_interface.sh
@@ -12,8 +12,9 @@ fw_configure_interface() {
 	}
 
 	[ -n "$ifname" ] || {
-		ifname=$(uci_get_state network "$iface" ifname "$iface")
+		ifname=$(uci_get_state network "$iface" ifname)
 		ifname="${ifname%%:*}"
+		[ -z "$ifname" ] && return 0
 	}
 
 	[ "$ifname" == "lo" ] && return 0
@@ -26,6 +27,8 @@ fw_configure_interface() {
 		local chain=zone_${zone}
 		local ifname=$3
 		local subnet=$4
+		local masq_src=$5
+		local masq_dest=$6
 
 		local inet onet
 		local mode=$(fw_get_family_mode x $zone i)
@@ -59,7 +62,16 @@ fw_configure_interface() {
 		fw $action $mode f ${chain}_REJECT reject $ { -o "$ifname" $onet }
 		fw $action $mode f ${chain}_REJECT reject $ { -i "$ifname" $inet }
 
-		fw $action $mode n ${chain}_nat MASQUERADE $ { -o "$ifname" $onet }
+		# NB: if MASQUERADING for IPv6 becomes available we'll need a family check here
+		local msrc mdst
+		for msrc in ${masq_src:-0.0.0.0/0}; do
+			[ "${msrc#!}" != "$msrc" ] && msrc="! -s ${msrc#!}" || msrc="-s $msrc"
+			for mdst in ${subnet:-${masq_dest:-0.0.0.0/0}}; do
+				[ "${mdst#!}" != "$mdst" ] && mdst="! -d ${mdst#!}" || mdst="-d $mdst"
+				fw $action $mode n ${chain}_nat MASQUERADE $ { -o "$ifname" $msrc $mdst }
+			done
+		done
+
 		fw $action $mode f ${chain}_MSSFIX TCPMSS  $ { -o "$ifname" -p tcp --tcp-flags SYN,RST SYN --clamp-mss-to-pmtu $onet }
 
 		fw $action $mode f input   ${chain}         $ { -i "$ifname" $inet }
@@ -68,18 +80,20 @@ fw_configure_interface() {
 		fw $action $mode r PREROUTING ${chain}_notrack    $ { -i "$ifname" $inet }
 	}
 
-	local old_zones old_ifname old_subnets
+	local old_zones old_ifname old_subnets old_masq_src old_masq_dest
 	config_get old_zones core "${iface}_zone"
 	[ -n "$old_zones" ] && {
 		config_get old_ifname core "${iface}_ifname"
 		config_get old_subnets core "${iface}_subnets"
+		config_get old_masq_src core "${iface}_masq_src"
+		config_get old_masq_dest core "${iface}_masq_dest"
 
 		local z
 		for z in $old_zones; do
 			local n
 			for n in ${old_subnets:-""}; do
 				fw_log info "removing $iface ($old_ifname${n:+ alias $n}) from zone $z"
-				fw__do_rules del $z $old_ifname $n
+				fw__do_rules del $z $old_ifname $n "$old_masq_src" "$old_masq_dest"
 			done
 
 			[ -n "$old_subnets" ] || ACTION=remove ZONE="$z" INTERFACE="$iface" DEVICE="$ifname" /sbin/hotplug-call firewall
@@ -97,6 +111,8 @@ fw_configure_interface() {
 		uci_revert_state firewall core "${iface}_ifname"
 		uci_revert_state firewall core "${iface}_subnets"
 		uci_revert_state firewall core "${iface}_aliases"
+		uci_revert_state firewall core "${iface}_masq_src"
+		uci_revert_state firewall core "${iface}_masq_dest"
 	}
 
 	[ "$action" == del ] && return
@@ -130,13 +146,17 @@ fw_configure_interface() {
 	}
 
 	local new_zones=
+	local new_masq_src=
+	local new_masq_dest=
 	load_zone() {
 		fw_config_get_zone "$1"
 		list_contains zone_network "$iface" || return
 
 		fw_log info "adding $iface ($ifname${aliasnet:+ alias $aliasnet}) to zone $zone_name"
-		fw__do_rules add ${zone_name} "$ifname" $aliasnet
+		fw__do_rules add ${zone_name} "$ifname" "$aliasnet" "$zone_masq_src" "$zone_masq_dest"
 		append new_zones $zone_name
+		append new_masq_src "$zone_masq_src"
+		append new_masq_dest "$zone_masq_dest"
 
 		[ -n "$aliasnet" ] || ACTION=add ZONE="$zone_name" INTERFACE="$iface" DEVICE="$ifname" /sbin/hotplug-call firewall
 	}
@@ -144,6 +164,8 @@ fw_configure_interface() {
 
 	uci_set_state firewall core "${iface}_zone" "$new_zones"
 	uci_set_state firewall core "${iface}_ifname" "$ifname"
+	uci_set_state firewall core "${iface}_masq_src" "$new_masq_src"
+	uci_set_state firewall core "${iface}_masq_dest" "$new_masq_dest"
 }
 
 fw_sysctl_interface() {
-- 
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