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         config_load /var/state/network
  10
  11         config_get WAN wan ifname
  12         config_get WANDEV wan device
  13         config_get LAN lan ifname
  14
  15         ## CLEAR TABLES
  16         for T in filter nat; do
  17                 iptables -t $T -F
  18                 iptables -t $T -X
  19         done
  20
  21         iptables -N input_rule
  22         iptables -N input_wan
  23         iptables -N output_rule
  24         iptables -N forwarding_rule
  25         iptables -N forwarding_wan
  26
  27         iptables -t nat -N NEW
  28         iptables -t nat -N prerouting_rule
  29         iptables -t nat -N prerouting_wan
  30         iptables -t nat -N postrouting_rule
  31
  32         iptables -N LAN_ACCEPT
  33         [ -z "$WAN" ] || iptables -A LAN_ACCEPT -i "$WAN" -j RETURN
  34         [ -z "$WANDEV" -o "$WANDEV" = "$WAN" ] || iptables -A LAN_ACCEPT -i "$WANDEV" -j RETURN
  35         iptables -A LAN_ACCEPT -j ACCEPT
  36
  37         ### INPUT
  38         ###  (connections with the router as destination)
  39
  40         # base case
  41         iptables -P INPUT DROP
  42         iptables -A INPUT -m state --state INVALID -j DROP
  43         iptables -A INPUT -m state --state RELATED,ESTABLISHED -j ACCEPT
  44         iptables -A INPUT -p tcp --tcp-flags SYN SYN --tcp-option \! 2 -j  DROP
  45
  46         #
  47         # insert accept rule or to jump to new accept-check table here
  48         #
  49         iptables -A INPUT -j input_rule
  50         [ -z "$WAN" ] || iptables -A INPUT -i $WAN -j input_wan
  51
  52         # allow
  53         iptables -A INPUT -j LAN_ACCEPT # allow from lan/wifi interfaces
  54         iptables -A INPUT -p icmp       -j ACCEPT       # allow ICMP
  55         iptables -A INPUT -p gre        -j ACCEPT       # allow GRE
  56
  57         # reject (what to do with anything not allowed earlier)
  58         iptables -A INPUT -p tcp -j REJECT --reject-with tcp-reset
  59         iptables -A INPUT -j REJECT --reject-with icmp-port-unreachable
  60
  61         ### OUTPUT
  62         ### (connections with the router as source)
  63
  64         # base case
  65         iptables -P OUTPUT DROP
  66         iptables -A OUTPUT -m state --state INVALID -j DROP
  67         iptables -A OUTPUT -m state --state RELATED,ESTABLISHED -j ACCEPT
  68
  69         #
  70         # insert accept rule or to jump to new accept-check table here
  71         #
  72         iptables -A OUTPUT -j output_rule
  73
  74         # allow
  75         iptables -A OUTPUT -j ACCEPT            #allow everything out
  76
  77         # reject (what to do with anything not allowed earlier)
  78         iptables -A OUTPUT -p tcp -j REJECT --reject-with tcp-reset
  79         iptables -A OUTPUT -j REJECT --reject-with icmp-port-unreachable
  80
  81         ### FORWARDING
  82         ### (connections routed through the router)
  83
  84         # base case
  85         iptables -P FORWARD DROP
  86         iptables -A FORWARD -m state --state INVALID -j DROP
  87         iptables -A FORWARD -p tcp --tcp-flags SYN,RST SYN -j TCPMSS --clamp-mss-to-pmtu
  88         iptables -A FORWARD -m state --state RELATED,ESTABLISHED -j ACCEPT
  89
  90         #
  91         # insert accept rule or to jump to new accept-check table here
  92         #
  93         iptables -A FORWARD -j forwarding_rule
  94         [ -z "$WAN" ] || iptables -A FORWARD -i $WAN -j forwarding_wan
  95
  96         # allow
  97         iptables -A FORWARD -i $LAN -o $LAN -j ACCEPT
  98         [ -z "$WAN" ] || iptables -A FORWARD -i $LAN -o $WAN -j ACCEPT
  99
 100         # reject (what to do with anything not allowed earlier)
 101         # uses the default -P DROP
 102
 103         ### MASQ
 104         iptables -t nat -A PREROUTING -m state --state NEW -p tcp -j NEW
 105         iptables -t nat -A PREROUTING -j prerouting_rule
 106         [ -z "$WAN" ] || iptables -t nat -A PREROUTING -i "$WAN" -j prerouting_wan
 107         iptables -t nat -A POSTROUTING -j postrouting_rule
 108         ### Only RFC1918 addresses
 109         [ -z "$WAN" ] || iptables -t nat -A POSTROUTING --src 192.168.0.0/16 -o $WAN -j MASQUERADE
 110         [ -z "$WAN" ] || iptables -t nat -A POSTROUTING --src 172.16.0.0/12 -o $WAN -j MASQUERADE
 111         [ -z "$WAN" ] || iptables -t nat -A POSTROUTING --src 10.0.0.0/8 -o $WAN -j MASQUERADE
 112
 113         iptables -t nat -A NEW -m limit --limit 50 --limit-burst 100 -j RETURN && \
 114                 iptables -t nat -A NEW -j DROP
 115
 116         ## USER RULES
 117         [ -f /etc/firewall.user ] && . /etc/firewall.user
 118         [ -n "$WAN" -a -e /etc/config/firewall ] && {
 119                 export WAN
 120                 awk -f /usr/lib/common.awk -f /usr/lib/firewall.awk /etc/config/firewall | ash
 121         }
 122 }
 123
 124 stop() {
 125         iptables -P INPUT ACCEPT
 126         iptables -P OUTPUT ACCEPT
 127         iptables -P FORWARD ACCEPT
 128         iptables -F
 129         iptables -X
 130         iptables -t nat -P PREROUTING ACCEPT
 131         iptables -t nat -P POSTROUTING ACCEPT
 132         iptables -t nat -P OUTPUT ACCEPT
 133         iptables -t nat -F
 134         iptables -t nat -X
 135 }