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         config_get_bool NAT_LAN lan nat 1
  14         if [ $NAT_LAN -ne 0 ]
  15         then
  16                 config_get LAN_MASK lan netmask
  17                 config_get LAN_IP lan ipaddr
  18                 LAN_NET=$(/bin/ipcalc.sh $LAN_IP $LAN_MASK | grep NETWORK | cut -d= -f2)
  19         fi
  20
  21         ## CLEAR TABLES
  22         for T in filter nat; do
  23                 iptables -t $T -F
  24                 iptables -t $T -X
  25         done
  26
  27         iptables -N input_rule
  28         iptables -N input_wan
  29         iptables -N output_rule
  30         iptables -N forwarding_rule
  31         iptables -N forwarding_wan
  32
  33         iptables -t nat -N NEW
  34         iptables -t nat -N prerouting_rule
  35         iptables -t nat -N prerouting_wan
  36         iptables -t nat -N postrouting_rule
  37
  38         iptables -N LAN_ACCEPT
  39         [ -z "$WAN" ] || iptables -A LAN_ACCEPT -i "$WAN" -j RETURN
  40         [ -z "$WANDEV" -o "$WANDEV" = "$WAN" ] || iptables -A LAN_ACCEPT -i "$WANDEV" -j RETURN
  41         iptables -A LAN_ACCEPT -j ACCEPT
  42
  43         ### INPUT
  44         ###  (connections with the router as destination)
  45
  46         # base case
  47         iptables -P INPUT DROP
  48         iptables -A INPUT -m state --state INVALID -j DROP
  49         iptables -A INPUT -m state --state RELATED,ESTABLISHED -j ACCEPT
  50         iptables -A INPUT -p tcp --tcp-flags SYN SYN --tcp-option \! 2 -j  DROP
  51
  52         #
  53         # insert accept rule or to jump to new accept-check table here
  54         #
  55         iptables -A INPUT -j input_rule
  56         [ -z "$WAN" ] || iptables -A INPUT -i $WAN -j input_wan
  57
  58         # allow
  59         iptables -A INPUT -j LAN_ACCEPT # allow from lan/wifi interfaces
  60         iptables -A INPUT -p icmp       -j ACCEPT       # allow ICMP
  61         iptables -A INPUT -p gre        -j ACCEPT       # allow GRE
  62
  63         # reject (what to do with anything not allowed earlier)
  64         iptables -A INPUT -p tcp -j REJECT --reject-with tcp-reset
  65         iptables -A INPUT -j REJECT --reject-with icmp-port-unreachable
  66
  67         ### OUTPUT
  68         ### (connections with the router as source)
  69
  70         # base case
  71         iptables -P OUTPUT DROP
  72         iptables -A OUTPUT -m state --state INVALID -j DROP
  73         iptables -A OUTPUT -m state --state RELATED,ESTABLISHED -j ACCEPT
  74
  75         #
  76         # insert accept rule or to jump to new accept-check table here
  77         #
  78         iptables -A OUTPUT -j output_rule
  79
  80         # allow
  81         iptables -A OUTPUT -j ACCEPT            #allow everything out
  82
  83         # reject (what to do with anything not allowed earlier)
  84         iptables -A OUTPUT -p tcp -j REJECT --reject-with tcp-reset
  85         iptables -A OUTPUT -j REJECT --reject-with icmp-port-unreachable
  86
  87         ### FORWARDING
  88         ### (connections routed through the router)
  89
  90         # base case
  91         iptables -P FORWARD DROP
  92         iptables -A FORWARD -m state --state INVALID -j DROP
  93         iptables -A FORWARD -p tcp --tcp-flags SYN,RST SYN -j TCPMSS --clamp-mss-to-pmtu
  94         iptables -A FORWARD -m state --state RELATED,ESTABLISHED -j ACCEPT
  95
  96         #
  97         # insert accept rule or to jump to new accept-check table here
  98         #
  99         iptables -A FORWARD -j forwarding_rule
 100         [ -z "$WAN" ] || iptables -A FORWARD -i $WAN -j forwarding_wan
 101
 102         # allow
 103         iptables -A FORWARD -i $LAN -o $LAN -j ACCEPT
 104         [ -z "$WAN" ] || iptables -A FORWARD -i $LAN -o $WAN -j ACCEPT
 105
 106         # reject (what to do with anything not allowed earlier)
 107         # uses the default -P DROP
 108
 109         ### MASQ
 110         iptables -t nat -A PREROUTING -m state --state NEW -p tcp -j NEW
 111         iptables -t nat -A PREROUTING -j prerouting_rule
 112         [ -z "$WAN" ] || iptables -t nat -A PREROUTING -i "$WAN" -j prerouting_wan
 113         iptables -t nat -A POSTROUTING -j postrouting_rule
 114         ### Only LAN, unless told not to
 115         if [ $NAT_LAN -ne 0 ]
 116         then
 117                 [ -z "$WAN" ] || iptables -t nat -A POSTROUTING --src $LAN_NET/$LAN_MASK -o $WAN -j MASQUERADE
 118         fi
 119
 120         iptables -t nat -A NEW -m limit --limit 50 --limit-burst 100 -j RETURN && \
 121                 iptables -t nat -A NEW -j DROP
 122
 123         ## USER RULES
 124         [ -f /etc/firewall.user ] && . /etc/firewall.user
 125         [ -n "$WAN" -a -e /etc/firewall.config ] && {
 126                 export WAN
 127                 awk -f /usr/lib/common.awk -f /usr/lib/firewall.awk /etc/firewall.config | ash
 128         }
 129 }
 130
 131 stop() {
 132         iptables -P INPUT ACCEPT
 133         iptables -P OUTPUT ACCEPT
 134         iptables -P FORWARD ACCEPT
 135         iptables -F
 136         iptables -X
 137         iptables -t nat -P PREROUTING ACCEPT
 138         iptables -t nat -P POSTROUTING ACCEPT
 139         iptables -t nat -P OUTPUT ACCEPT
 140         iptables -t nat -F
 141         iptables -t nat -X
 142 }