#!/bin/sh

# Copyright 2014 Google Inc. All Rights Reserved.
#

. /etc/utils.sh

# refreshes the rules in the acsrules chains based on acs settings
# wan is wan0/wan0.2 on optimus/gfrg200
wan=$(activewan)
wans=wan0+

wanipv4=$(ip -4 -o addr show $wan)
wanipv4=${wanipv4#* inet }
wanipv4mask=${wanipv4%% *}
wanipv4=${wanipv4%%/*}

lanipv4=$(ip -4 -o addr show br0)
lanipv4=${lanipv4#* inet }
lanipv4mask=${lanipv4%% *}
lanipv4=${lanipv4%%/*}

wanipv6=$(ip -6 -o addr show $wan)
wanipv6=${wanipv6#* inet }
wanipv6mask=${wanipv6%% *}
wanipv6=${wanipv6%%/*}

lanipv6=$(ip -6 -o addr show br0)
lanipv6=${lanipv6#* inet6 }
lanipv6mask=${lanipv6%% *}
lanipv6=${lanipv6%%/*}

# presumes acsrules chains are created (by S39firewall)

acs=/tmp/acs

# clear out any existing rules
ip46tables -t filter -F acsrules-filter-forward
iptables -t nat -F acsrules-nat-prerouting
iptables -t nat -F acsrules-nat-postrouting

# ipv4 port mapping rules
file=/tmp/cwmp_iptables
if [ -f "$file" ]; then
  while IFS="," read -r comment protocol dest sport dport enabled src gateway;
  do
    if [ "$enabled" != 1 ]; then
      continue
    fi

    isrange=$( (echo "$sport" | grep -q ":") && echo 1 )
    if [ ! "$isrange" ]; then
      dportnat=":$dport"
    else
      if [ "$sport" != "$dport" ]; then
        echo "$0: $comment: source port range ($sport) does not match dest port range ($dport)" 1>&2
        continue
      fi
      dportnat=
    fi

    iptables -t nat -A acsrules-nat-prerouting -i "$wans" -p "$protocol" -s "$src" -d "$gateway" --dport "$sport" \
      -j DNAT --to "$dest$dportnat" -m comment --comment "$comment"
    if [ -n "$lanipv4" ]; then
      iptables -t nat -A acsrules-nat-postrouting -p "$protocol" -s "$lanipv4mask" -d "$dest" --dport "$dport" \
        -j SNAT --to "$lanipv4" -m comment --comment "$comment"
    else
      echo "$0: $comment: No IPv4 LAN address assigned." 1>&2
    fi
    iptables -A acsrules-filter-forward -p "$protocol" -d "$dest" --dport "$dport" -j ACCEPT \
      -m comment --comment "$comment"
    # this adds a lan rule so internal hosts can use the wan router ip to get the same mapping
    if ( [ "$gateway" = "$wanipv4" ] || [ "$gateway" = 0/0 ] ) && [ "$src" = 0/0 ]; then
      iptables -t nat -A acsrules-nat-prerouting -i br0 -p "$protocol" -d "$wanipv4" --dport "$sport" \
        -j DNAT --to "$dest$dportnat" -m comment --comment "$comment"
    fi
  done <$file
fi

# ipv6 port mapping rules
file=/tmp/cwmp_ip6tables
if [ -f "$file" ]; then
  while IFS="," read -r comment protocol dest sport dport enabled src gateway;
  do
    if [ "$enabled" != 1 ]; then
      continue
    fi

    ip6tables -A acsrules-filter-forward -p "$protocol" -s "$src" -d "$dest" --sport "$sport" --dport "$dport" -j ACCEPT -m comment --comment "$comment"
  done <$file
fi

# upnp IGD (firewall pinholes)
# MINIUPNPD is maintained by miniupnpd
if [ -f /tmp/upnpd-enabled ]; then
  ip46tables -t filter -A acsrules-filter-forward -i $wans ! -o $wans -j MINIUPNPD
  iptables -t nat -A acsrules-nat-prerouting -d "$wanipv4" -i $wans -j MINIUPNPD
  ! /etc/init.d/S80upnpd isrunning && /etc/init.d/S80upnpd start
else
  QUIET=1 stop upnpd
fi

# ftp server
if [ -f $acs/ftpserverv4 ]; then
  ftpserverv4=$(cat $acs/ftpserverv4)
  iptables -t nat -A acsrules-nat-prerouting -p tcp ---dport 20 -j DNAT \
      --to "$ftpserverv4":20 -m comment --comment "ASF:FTP"
  iptables -t nat -A acsrules-nat-prerouting -p tcp --dport 21 -j DNAT \
      --to "$ftpserverv4":21 -m comment --comment "ASF:FTP"
  iptables -A acsrules-filter-forward -p tcp -d "$ftpserverv4" --dport 21 \
      -m conntrack --ctstate NEW,ESTABLISHED ftp \
      -j ACCEPT -m comment --comment "ASF:FTP"
  iptables -A acsrules-filter-forward -p tcp -d "$ftpserverv4" --dport 20 \
      -m conntrack --ctstate RELATED -m helper --helper ftp -j ACCEPT \
      -m comment --comment "ASF:FTP"
  iptables -A acsrules-filter-forward -p tcp -d "$ftpserverv4" --dport 1024: \
      -m conntrack --ctstate RELATED -m helper --helper ftp -j ACCEPT \
      -m comment --comment "ASF:FTP"
fi
if [ -f $acs/ftpserverv6 ]; then
  ftpserverv6=$(cat $acs/ftpserverv6)
  ip6tables -A acsrules-filter-forward -p tcp -d "$ftpserverv6" --dport 21 \
      -m conntrack --ctstate NEW,ESTABLISHED ftp -j ACCEPT \
      -m comment --comment "ASF:FTP6"
  ip6tables -A acsrules-filter-forward -p tcp -d "$ftpserverv6" --dport 20 \
      -m conntrack --ctstate RELATED -m helper --helper ftp -j ACCEPT \
      -m comment --comment "ASF:FTP6"
  ip6tables -A acsrules-filter-forward -p tcp -d "$ftpserverv6" --dport 1024: \
      -m conntrack --ctstate RELATED -m helper --helper ftp -j ACCEPT \
      -m comment --comment "ASF:FTP6"
fi

# DMZ, goes last
if [ -f $acs/dmzhostv4 ]; then
  file_contents=$(cat $acs/dmzhostv4)
  # TODO(jnewlin): Change this to use while x .. < $acs/dmzhostv4
  # after catawampus if fixed to append a newline to the end of the file.
  echo "$file_contents" | while read dmz_lanv4 dmz_wanv4; do
    if [ -z "$dmz_wanv4" ]; then
      # Legacy case, map everything from the wans ip to the lan_ip
      dmz_wanv4="$wanipv4"
    fi
    # Map external dmz_wanv4 to internal dmz_lanv4.
    iptables -t nat -A acsrules-nat-prerouting -i $wan -s 0/0 \
      -d "$dmz_wanv4" -j DNAT --to "$dmz_lanv4" -m comment --comment "DMZ4"

    # Map traffic coming from internal dmz_lanv4 to have a source address of
    # dmz_wanv4.
    iptables -t nat -A acsrules-nat-postrouting -o $wan -s "$dmz_lanv4" \
      -j SNAT --to "$dmz_wanv4"  -m comment --comment "DMZ4"

    # Allows any traffic to be forwarded through the firewall to this lan
    # ipv4 address.
    iptables -A acsrules-filter-forward -i $wan -d "$dmz_lanv4" -j ACCEPT  \
      -m comment --comment "DMZ4"
  done
fi
if [ -f $acs/dmzhostv6 ]; then
  dmzhostv6=$(cat $acs/dmzhostv6)
  iptables -A acsrules-filter-forward -i $wan -d "$dmzhostv6" -j ACCEPT \
      -m comment --comment "DMZ6"
fi

(iptables-save; ip6tables-save) | logos iptables-save

exit 0