large init script cleanup and merge of whiterussian changes, new dnsmasq config handling

git-svn-id: svn://svn.openwrt.org/openwrt/trunk/openwrt@3588 3c298f89-4303-0410-b956-a3cf2f4a3e73

package/iptables/files/firewall.init

@@ -0,0 +1,95 @@
+#!/bin/sh
+
+## Please make changes in /etc/firewall.user
+
+. /etc/config/network
+WAN="$wan_ifname"
+LAN="$lan_ifname"
+
+## CLEAR TABLES
+for T in filter nat; do
+  iptables -t $T -F
+  iptables -t $T -X
+done
+
+iptables -N input_rule
+iptables -N output_rule
+iptables -N forwarding_rule
+
+iptables -t nat -N prerouting_rule
+iptables -t nat -N postrouting_rule
+
+### INPUT
+###  (connections with the router as destination)
+
+  # base case
+  iptables -P INPUT DROP
+  iptables -A INPUT -m state --state INVALID -j DROP
+  iptables -A INPUT -m state --state RELATED,ESTABLISHED -j ACCEPT
+  iptables -A INPUT -p tcp --tcp-flags SYN SYN --tcp-option \! 2 -j  DROP
+
+  #
+  # insert accept rule or to jump to new accept-check table here
+  #
+  iptables -A INPUT -j input_rule
+
+  # allow
+  [ -z "$WAN" ] || iptables -A INPUT -i \! $WAN	-j ACCEPT	# allow from lan/wifi interfaces 
+  iptables -A INPUT -p icmp	-j ACCEPT	# allow ICMP
+  iptables -A INPUT -p gre	-j ACCEPT	# allow GRE
+
+  # reject (what to do with anything not allowed earlier)
+  iptables -A INPUT -p tcp -j REJECT --reject-with tcp-reset
+  iptables -A INPUT -j REJECT --reject-with icmp-port-unreachable
+
+### OUTPUT
+### (connections with the router as source)
+
+  # base case
+  iptables -P OUTPUT DROP
+  iptables -A OUTPUT -m state --state INVALID -j DROP
+  iptables -A OUTPUT -m state --state RELATED,ESTABLISHED -j ACCEPT
+
+  #
+  # insert accept rule or to jump to new accept-check table here
+  #
+  iptables -A OUTPUT -j output_rule
+
+  # allow
+  iptables -A OUTPUT -j ACCEPT		#allow everything out
+
+  # reject (what to do with anything not allowed earlier)
+  iptables -A OUTPUT -p tcp -j REJECT --reject-with tcp-reset
+  iptables -A OUTPUT -j REJECT --reject-with icmp-port-unreachable
+
+### FORWARDING
+### (connections routed through the router)
+
+  # base case
+  iptables -P FORWARD DROP 
+  iptables -A FORWARD -m state --state INVALID -j DROP
+  iptables -A FORWARD -p tcp --tcp-flags SYN,RST SYN -j TCPMSS --clamp-mss-to-pmtu
+  iptables -A FORWARD -m state --state RELATED,ESTABLISHED -j ACCEPT
+
+  #
+  # insert accept rule or to jump to new accept-check table here
+  #
+  iptables -A FORWARD -j forwarding_rule
+
+  # allow
+  iptables -A FORWARD -i br0 -o br0 -j ACCEPT
+  [ -z "$WAN" ] || iptables -A FORWARD -i $LAN -o $WAN -j ACCEPT
+
+  # reject (what to do with anything not allowed earlier)
+  # uses the default -P DROP
+
+### MASQ
+  iptables -t nat -A PREROUTING -j prerouting_rule
+  iptables -t nat -A POSTROUTING -j postrouting_rule
+  [ -z "$WAN" ] || iptables -t nat -A POSTROUTING -o $WAN -j MASQUERADE
+
+## USER RULES
+[ -f /etc/firewall.user ] && . /etc/firewall.user
+[ -n "$WAN" -a -e /etc/config/firewall ] && {
+	awk -f /usr/lib/common.awk -f /usr/lib/firewall.awk /etc/config/firewall | ash
+}