[backfire] firewall: backport SNAT support from trunk

git-svn-id: svn://svn.openwrt.org/openwrt/branches/backfire@22939 3c298f89-4303-0410-b956-a3cf2f4a3e73

package/firewall/Makefile

@@ -9,7 +9,7 @@ include $(TOPDIR)/rules.mk
 PKG_NAME:=firewall
 
 PKG_VERSION:=1
-PKG_RELEASE:=14
+PKG_RELEASE:=15
 
 include $(INCLUDE_DIR)/package.mk
 

package/firewall/files/reflection.hotplug

@@ -41,7 +41,10 @@ if [ "$ACTION" = "add" ] && [ "$INTERFACE" = "wan" ]; then
 		local src
 		config_get src "$cfg" src
 
-		[ "$src" = wan ] && {
+		local target
+		config_get target "$cfg" target
+
+		[ "$src" = wan ] && [ "${target:-DNAT}" = DNAT ] && {
 			local dest
 			config_get dest "$cfg" dest "lan"
 

package/firewall/files/uci_firewall.sh

@@ -372,6 +372,7 @@ fw_redirect() {
 	local dest_ip
 	local dest_port dest_port2
 	local proto
+	local target
 
 	config_get src $1 src
 	config_get src_ip $1 src_ip
@@ -382,9 +383,25 @@ fw_redirect() {
 	config_get dest_ip $1 dest_ip
 	config_get dest_port $1 dest_port
 	config_get proto $1 proto
+	config_get target $1 target
+
 	[ -z "$src" -o -z "$dest_ip$dest_port" ] && { \
 		echo "redirect needs src and dest_ip or dest_port"; return ; }
 
+	local chain destopt destaddr
+	if [ "${target:-DNAT}" == "DNAT" ]; then
+		chain="zone_${src}_prerouting"
+		destopt="--to-destination"
+		destaddr="$dest_ip"
+	elif [ "$target" == "SNAT" ]; then
+		chain="zone_${src}_nat"
+		destopt="--to-source"
+		destaddr="$src_dip"
+	else
+		echo "redirect target must be either DNAT or SNAT"
+		return
+	fi
+
 	find_item "$src" $CONNTRACK_ZONES || \
 		append CONNTRACK_ZONES "$src"
 
@@ -405,19 +422,19 @@ fw_redirect() {
 		dest_port2="$dest_port_first:$dest_port_last"; }
 
 	add_rule() {
-		$IPTABLES -A zone_${src}_prerouting -t nat \
+		$IPTABLES -A $chain -t nat \
 			${proto:+-p $proto} \
 			${src_ip:+-s $src_ip} \
 			${src_dip:+-d $src_dip} \
 			${src_port:+--sport $src_port} \
 			${src_dport:+--dport $src_dport} \
 			${src_mac:+-m mac --mac-source $src_mac} \
-			-j DNAT --to-destination $dest_ip${dest_port:+:$dest_port}
+			-j ${target:-DNAT} $destopt $dest_ip${dest_port:+:$dest_port}
 
-		[ -n "$dest_ip" ] && \
+		[ -n "$destaddr" ] && \
 		$IPTABLES -I zone_${src}_forward 1 \
 			${proto:+-p $proto} \
-			-d $dest_ip \
+			-d $destaddr \
 			${src_ip:+-s $src_ip} \
 			${src_port:+--sport $src_port} \
 			${dest_port2:+--dport $dest_port2} \