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