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 WANDEV wan device
  12         config_get LAN lan ifname
  13
  14         ## CLEAR TABLES
  15         for T in filter nat; do
  16                 iptables -t $T -F
  17                 iptables -t $T -X
  18         done
  19
  20         iptables -N input_rule
  21         iptables -N input_wan
  22         iptables -N output_rule
  23         iptables -N forwarding_rule
  24         iptables -N forwarding_wan
  25
  26         iptables -t nat -N prerouting_rule
  27         iptables -t nat -N prerouting_wan
  28         iptables -t nat -N postrouting_rule
  29
  30         iptables -N LAN_ACCEPT
  31         [ -z "$WAN" ] || iptables -A LAN_ACCEPT -i "$WAN" -j RETURN
  32         [ -z "$WANDEV" -o "$WANDEV" = "$WAN" ] || iptables -A LAN_ACCEPT -i "$WANDEV" -j RETURN
  33         iptables -A LAN_ACCEPT -j ACCEPT
  34
  35         ### INPUT
  36         ###  (connections with the router as destination)
  37
  38         # base case
  39         iptables -P INPUT DROP
  40         iptables -A INPUT -m state --state INVALID -j DROP
  41         iptables -A INPUT -m state --state RELATED,ESTABLISHED -j ACCEPT
  42         iptables -A INPUT -p tcp --tcp-flags SYN SYN --tcp-option \! 2 -j  DROP
  43
  44         #
  45         # insert accept rule or to jump to new accept-check table here
  46         #
  47         iptables -A INPUT -j input_rule
  48         [ -z "$WAN" ] || iptables -A INPUT -i $WAN -j input_wan
  49
  50         # allow
  51         iptables -A INPUT -j LAN_ACCEPT # allow from lan/wifi interfaces
  52         iptables -A INPUT -p icmp       -j ACCEPT       # allow ICMP
  53         iptables -A INPUT -p gre        -j ACCEPT       # allow GRE
  54
  55         # reject (what to do with anything not allowed earlier)
  56         iptables -A INPUT -p tcp -j REJECT --reject-with tcp-reset
  57         iptables -A INPUT -j REJECT --reject-with icmp-port-unreachable
  58
  59         ### OUTPUT
  60         ### (connections with the router as source)
  61
  62         # base case
  63         iptables -P OUTPUT DROP
  64         iptables -A OUTPUT -m state --state INVALID -j DROP
  65         iptables -A OUTPUT -m state --state RELATED,ESTABLISHED -j ACCEPT
  66
  67         #
  68         # insert accept rule or to jump to new accept-check table here
  69         #
  70         iptables -A OUTPUT -j output_rule
  71
  72         # allow
  73         iptables -A OUTPUT -j ACCEPT            #allow everything out
  74
  75         # reject (what to do with anything not allowed earlier)
  76         iptables -A OUTPUT -p tcp -j REJECT --reject-with tcp-reset
  77         iptables -A OUTPUT -j REJECT --reject-with icmp-port-unreachable
  78
  79         ### FORWARDING
  80         ### (connections routed through the router)
  81
  82         # base case
  83         iptables -P FORWARD DROP
  84         iptables -A FORWARD -m state --state INVALID -j DROP
  85         iptables -A FORWARD -p tcp --tcp-flags SYN,RST SYN -j TCPMSS --clamp-mss-to-pmtu
  86         iptables -A FORWARD -m state --state RELATED,ESTABLISHED -j ACCEPT
  87
  88         #
  89         # insert accept rule or to jump to new accept-check table here
  90         #
  91         iptables -A FORWARD -j forwarding_rule
  92         [ -z "$WAN" ] || iptables -A FORWARD -i $WAN -j forwarding_wan
  93
  94         # allow
  95         iptables -A FORWARD -i $LAN -o $LAN -j ACCEPT
  96         [ -z "$WAN" ] || iptables -A FORWARD -i $LAN -o $WAN -j ACCEPT
  97
  98         # reject (what to do with anything not allowed earlier)
  99         # uses the default -P DROP
 100
 101         ### MASQ
 102         iptables -t nat -A PREROUTING -j prerouting_rule
 103         [ -z "$WAN" ] || iptables -t nat -A PREROUTING -i "$WAN" -j prerouting_wan
 104         iptables -t nat -A POSTROUTING -j postrouting_rule
 105         [ -z "$WAN" ] || iptables -t nat -A POSTROUTING -o $WAN -j MASQUERADE
 106
 107         ## USER RULES
 108         [ -f /etc/firewall.user ] && . /etc/firewall.user
 109         [ -n "$WAN" -a -e /etc/config/firewall ] && {
 110                 export WAN
 111                 awk -f /usr/lib/common.awk -f /usr/lib/firewall.awk /etc/config/firewall | ash
 112         }
 113 }
 114
 115 stop() {
 116         iptables -P INPUT ACCEPT
 117         iptables -P OUTPUT ACCEPT
 118         iptables -P FORWARD ACCEPT
 119         iptables -F
 120         iptables -X
 121         iptables -t nat -P PREROUTING ACCEPT
 122         iptables -t nat -P POSTROUTING ACCEPT
 123         iptables -t nat -P OUTPUT ACCEPT
 124         iptables -t nat -F
 125         iptables -t nat -X
 126 }