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