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_bool NAT_LAN lan nat 1
  15         if [ $NAT_LAN -ne 0 ]
  16         then
  17                 config_get LAN_MASK lan netmask
  18                 config_get LAN_IP lan ipaddr
  19                 LAN_NET=$(/bin/ipcalc.sh $LAN_IP $LAN_MASK | grep NETWORK | cut -d= -f2)
  20         fi
  21
  22         ## CLEAR TABLES
  23         for T in filter nat; do
  24                 iptables -t $T -F
  25                 iptables -t $T -X
  26         done
  27
  28         iptables -N input_rule
  29         iptables -N input_wan
  30         iptables -N output_rule
  31         iptables -N forwarding_rule
  32         iptables -N forwarding_wan
  33
  34         iptables -t nat -N NEW
  35         iptables -t nat -N prerouting_rule
  36         iptables -t nat -N prerouting_wan
  37         iptables -t nat -N postrouting_rule
  38
  39         iptables -N LAN_ACCEPT
  40         [ -z "$WAN" ] || iptables -A LAN_ACCEPT -i "$WAN" -j RETURN
  41         [ -z "$WANDEV" -o "$WANDEV" = "$WAN" ] || iptables -A LAN_ACCEPT -i "$WANDEV" -j RETURN
  42         iptables -A LAN_ACCEPT -j ACCEPT
  43
  44         ### INPUT
  45         ###  (connections with the router as destination)
  46
  47         # base case
  48         iptables -P INPUT DROP
  49         iptables -A INPUT -m state --state INVALID -j DROP
  50         iptables -A INPUT -m state --state RELATED,ESTABLISHED -j ACCEPT
  51         iptables -A INPUT -p tcp --tcp-flags SYN SYN --tcp-option \! 2 -j  DROP
  52
  53         #
  54         # insert accept rule or to jump to new accept-check table here
  55         #
  56         iptables -A INPUT -j input_rule
  57         [ -z "$WAN" ] || iptables -A INPUT -i $WAN -j input_wan
  58
  59         # allow
  60         iptables -A INPUT -j LAN_ACCEPT # allow from lan/wifi interfaces
  61         iptables -A INPUT -p icmp       -j ACCEPT       # allow ICMP
  62         iptables -A INPUT -p gre        -j ACCEPT       # allow GRE
  63
  64         # reject (what to do with anything not allowed earlier)
  65         iptables -A INPUT -p tcp -j REJECT --reject-with tcp-reset
  66         iptables -A INPUT -j REJECT --reject-with icmp-port-unreachable
  67
  68         ### OUTPUT
  69         ### (connections with the router as source)
  70
  71         # base case
  72         iptables -P OUTPUT DROP
  73         iptables -A OUTPUT -m state --state INVALID -j DROP
  74         iptables -A OUTPUT -m state --state RELATED,ESTABLISHED -j ACCEPT
  75
  76         #
  77         # insert accept rule or to jump to new accept-check table here
  78         #
  79         iptables -A OUTPUT -j output_rule
  80
  81         # allow
  82         iptables -A OUTPUT -j ACCEPT            #allow everything out
  83
  84         # reject (what to do with anything not allowed earlier)
  85         iptables -A OUTPUT -p tcp -j REJECT --reject-with tcp-reset
  86         iptables -A OUTPUT -j REJECT --reject-with icmp-port-unreachable
  87
  88         ### FORWARDING
  89         ### (connections routed through the router)
  90
  91         # base case
  92         iptables -P FORWARD DROP
  93         iptables -A FORWARD -m state --state INVALID -j DROP
  94         iptables -A FORWARD -p tcp --tcp-flags SYN,RST SYN -j TCPMSS --clamp-mss-to-pmtu
  95         iptables -A FORWARD -m state --state RELATED,ESTABLISHED -j ACCEPT
  96
  97         #
  98         # insert accept rule or to jump to new accept-check table here
  99         #
 100         iptables -A FORWARD -j forwarding_rule
 101         [ -z "$WAN" ] || iptables -A FORWARD -i $WAN -j forwarding_wan
 102
 103         # allow
 104         iptables -A FORWARD -i $LAN -o $LAN -j ACCEPT
 105         [ -z "$WAN" ] || iptables -A FORWARD -i $LAN -o $WAN -j ACCEPT
 106
 107         # reject (what to do with anything not allowed earlier)
 108         # uses the default -P DROP
 109
 110         ### MASQ
 111         iptables -t nat -A PREROUTING -m state --state NEW -p tcp -j NEW
 112         iptables -t nat -A PREROUTING -j prerouting_rule
 113         [ -z "$WAN" ] || iptables -t nat -A PREROUTING -i "$WAN" -j prerouting_wan
 114         iptables -t nat -A POSTROUTING -j postrouting_rule
 115         ### Only LAN, unless told not to
 116         if [ $NAT_LAN -ne 0 ]
 117         then
 118                 [ -z "$WAN" ] || iptables -t nat -A POSTROUTING --src $LAN_NET/$LAN_MASK -o $WAN -j MASQUERADE
 119         fi
 120
 121         iptables -t nat -A NEW -m limit --limit 50 --limit-burst 100 -j RETURN && \
 122                 iptables -t nat -A NEW -j DROP
 123
 124         ## USER RULES
 125         [ -f /etc/firewall.user ] && . /etc/firewall.user
 126         [ -n "$WAN" -a -e /etc/config/firewall ] && {
 127                 export WAN
 128                 awk -f /usr/lib/common.awk -f /usr/lib/firewall.awk /etc/config/firewall | ash
 129         }
 130 }
 131
 132 stop() {
 133         iptables -P INPUT ACCEPT
 134         iptables -P OUTPUT ACCEPT
 135         iptables -P FORWARD ACCEPT
 136         iptables -F
 137         iptables -X
 138         iptables -t nat -P PREROUTING ACCEPT
 139         iptables -t nat -P POSTROUTING ACCEPT
 140         iptables -t nat -P OUTPUT ACCEPT
 141         iptables -t nat -F
 142         iptables -t nat -X
 143 }