package/iptables/files/firewall.init

   1 #!/bin/sh /etc/rc.common
   2 # Copyright (C) 2006 OpenWrt.org
   3
   4 ## Please make changes in /etc/firewall.user
   5 START=45
   6 start() {
   7         include /lib/network
   8         scan_interfaces
   9
  10         config_get WAN wan ifname
  11         config_get LAN lan ifname
  12
  13         ## CLEAR TABLES
  14         for T in filter nat; do
  15                 iptables -t $T -F
  16                 iptables -t $T -X
  17         done
  18
  19         iptables -N input_rule
  20         iptables -N output_rule
  21         iptables -N forwarding_rule
  22
  23         iptables -t nat -N prerouting_rule
  24         iptables -t nat -N postrouting_rule
  25
  26         iptables -N LAN_ACCEPT
  27         [ -z "$WAN" ] || iptables -A LAN_ACCEPT -i "$WAN" -j RETURN
  28         iptables -A LAN_ACCEPT -j ACCEPT
  29
  30         ### INPUT
  31         ###  (connections with the router as destination)
  32
  33         # base case
  34         iptables -P INPUT DROP
  35         iptables -A INPUT -m state --state INVALID -j DROP
  36         iptables -A INPUT -m state --state RELATED,ESTABLISHED -j ACCEPT
  37         iptables -A INPUT -p tcp --tcp-flags SYN SYN --tcp-option \! 2 -j  DROP
  38
  39         #
  40         # insert accept rule or to jump to new accept-check table here
  41         #
  42         iptables -A INPUT -j input_rule
  43
  44         # allow
  45         iptables -A INPUT -j LAN_ACCEPT # allow from lan/wifi interfaces
  46         iptables -A INPUT -p icmp       -j ACCEPT       # allow ICMP
  47         iptables -A INPUT -p gre        -j ACCEPT       # allow GRE
  48
  49         # reject (what to do with anything not allowed earlier)
  50         iptables -A INPUT -p tcp -j REJECT --reject-with tcp-reset
  51         iptables -A INPUT -j REJECT --reject-with icmp-port-unreachable
  52
  53         ### OUTPUT
  54         ### (connections with the router as source)
  55
  56         # base case
  57         iptables -P OUTPUT DROP
  58         iptables -A OUTPUT -m state --state INVALID -j DROP
  59         iptables -A OUTPUT -m state --state RELATED,ESTABLISHED -j ACCEPT
  60
  61         #
  62         # insert accept rule or to jump to new accept-check table here
  63         #
  64         iptables -A OUTPUT -j output_rule
  65
  66         # allow
  67         iptables -A OUTPUT -j ACCEPT            #allow everything out
  68
  69         # reject (what to do with anything not allowed earlier)
  70         iptables -A OUTPUT -p tcp -j REJECT --reject-with tcp-reset
  71         iptables -A OUTPUT -j REJECT --reject-with icmp-port-unreachable
  72
  73         ### FORWARDING
  74         ### (connections routed through the router)
  75
  76         # base case
  77         iptables -P FORWARD DROP
  78         iptables -A FORWARD -m state --state INVALID -j DROP
  79         iptables -A FORWARD -p tcp --tcp-flags SYN,RST SYN -j TCPMSS --clamp-mss-to-pmtu
  80         iptables -A FORWARD -m state --state RELATED,ESTABLISHED -j ACCEPT
  81
  82         #
  83         # insert accept rule or to jump to new accept-check table here
  84         #
  85         iptables -A FORWARD -j forwarding_rule
  86
  87         # allow
  88         iptables -A FORWARD -i br0 -o br0 -j ACCEPT
  89         [ -z "$WAN" ] || iptables -A FORWARD -i $LAN -o $WAN -j ACCEPT
  90
  91         # reject (what to do with anything not allowed earlier)
  92         # uses the default -P DROP
  93
  94         ### MASQ
  95         iptables -t nat -A PREROUTING -j prerouting_rule
  96         iptables -t nat -A POSTROUTING -j postrouting_rule
  97         [ -z "$WAN" ] || iptables -t nat -A POSTROUTING -o $WAN -j MASQUERADE
  98
  99         ## USER RULES
 100         [ -f /etc/firewall.user ] && . /etc/firewall.user
 101         [ -n "$WAN" -a -e /etc/config/firewall ] && {
 102                 awk -f /usr/lib/common.awk -f /usr/lib/firewall.awk /etc/config/firewall | ash
 103         }
 104 }
 105
 106 stop() {
 107         iptables -P INPUT ACCEPT
 108         iptables -P OUTPUT ACCEPT
 109         iptables -P FORWARD ACCEPT
 110         iptables -F
 111         iptables -t nat -P PREROUTING ACCEPT
 112         iptables -t nat -P POSTROUTING ACCEPT
 113         iptables -t nat -P OUTPUT ACCEPT
 114         iptables -t nat -F
 115 }