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