[firewall] / local.m4

### -*-sh-*-
###
### Local firewall configuration
###
### (c) 2008 Mark Wooding
###

###----- Licensing notice ---------------------------------------------------
###
### This program is free software; you can redistribute it and/or modify
### it under the terms of the GNU General Public License as published by
### the Free Software Foundation; either version 2 of the License, or
### (at your option) any later version.
###
### This program is distributed in the hope that it will be useful,
### but WITHOUT ANY WARRANTY; without even the implied warranty of
### MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
### GNU General Public License for more details.
###
### You should have received a copy of the GNU General Public License
### along with this program; if not, write to the Free Software Foundation,
### Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.

###--------------------------------------------------------------------------
### Local configuration.

m4_divert(6)m4_dnl
## Default NTP servers.
defconf(ntp_servers,
	"158.152.1.76 158.152.1.204 194.159.253.2 195.173.57.232")

m4_divert(-1)
###--------------------------------------------------------------------------
### Packet classification.

## IPv4 addressing.
##
## There are two small blocks of publicly routable IPv4 addresses, and a
## block of RFC1918 private-use addresses allocated from the Cambridge G-RIN.
## The former are as follows.
##
## 62.49.204.144/28
##		House border network (dmz).  We have all of these, but .145
##		is reserved for the router.
##
## 212.13.18.64/28
##		Jump colocated network (jump).  .65--68 are used by Jump
##		network infrastructure; we get the rest.
##
## The latter is the block 172.29.196.0/22.  Currently the low half is
## unallocated (and may be returned to the G-RIN); the remaining addresses
## are allocated as follows.
##
## 172.29.198.0/24  Untrusted networks.
##	.0/25		house wireless net
##	.128/28		iodine (IP-over-DNS) network
##
## 172.29.199.0/24  Trusted networks.
##	.0/25		house wired network
##	.128/27		mobile VPN hosts
##	.160/28		reserved, except .160/30 allocated for ITS
##	.176/28		internal colocated network
##	.192/27		house safe network
##	.224/27		anycast services

## IPv6 addressing.
##
## There are five blocks of publicly routable IPv6 addresses, though some of
## them aren't very interesting.  The ranges are as follows.
##
## 2001:470:1f08:1b98::/64
##		Hurricane Electric tunnel network: only :1 (HE) and :2
##		(radius) are used.
##
## 2001:470:1f09:1b98::/64
##		House border network (dmz).
##
## 2001:470:9740::/48
##		Main house range.  See below for allocation policy.
##
## 2001:ba8:0:1d9::/64
##		Jump border network (jump): :1 is the router (supplied by
##		Jump); other addresses are ours.
##
## 2001:ba8:1d9::/48
##		Main colocated range.  See below for allocation policy.
##
## Addresses in the /64 networks are simply allocated in ascending order.
## The /48s are split into /64s by appending a 16-bit network number.  The
## top nibble of the network number classifies the network, as follows.
##
## 8xxx		Untrusted
## 6xxx		Virtual, safe
## 4xxx		Safe
## 0xxx		Unsafe, trusted
##
## These have been chosen so that network properties can be deduced by
## inspecting bits of the network number:
##
## Bit 15	If set, the network is untrusted; otherwise it is trusted.
## Bit 14	If set, the network is safe; otherwise it is unsafe.
##
## Finally, the low-order nibbles identify the site.
##
## 0		No specific site: mobile VPN endpoints or anycast addresses.
## 1		House.
## 2		Jump colocation.
##
## Usually site-0 networks are allocated from the Jump range to improve
## expected performance from/to external sites which don't engage in our
## dynamic routing protocols.

## Define the available network classes.
m4_divert(42)m4_dnl
defnetclass untrusted	untrusted trusted	      mcast
defnetclass trusted	untrusted trusted safe noloop mcast
defnetclass safe	          trusted safe noloop mcast
defnetclass noloop		  trusted safe	      mcast

defnetclass link
defnetclass mcast
m4_divert(-1)

m4_divert(26)m4_dnl
###--------------------------------------------------------------------------
### Network layout.

## House networks.
defnet dmz trusted
	addr 62.49.204.144/28 2001:470:1f09:1b98::/64
	via unsafe untrusted
defnet unsafe trusted
	addr 172.29.199.0/25 2001:470:9740:1::/64
	via househub
defnet safe safe
	addr 172.29.199.192/27 2001:470:9740:4001::/64
	via househub
defnet untrusted untrusted
	addr 172.29.198.0/25 2001:470:9740:8001::/64
	via househub

defnet househub virtual
	via housebdry dmz unsafe safe untrusted
defnet housebdry virtual
	via househub hub

## House hosts.
defhost radius
	hosttype router
	iface eth0 dmz unsafe safe untrusted vpn sgo colobdry default
	iface eth1 dmz unsafe safe untrusted vpn sgo colobdry default
	iface eth2 dmz unsafe safe untrusted vpn sgo colobdry
	iface eth3 unsafe untrusted vpn default
	iface ppp0 default
	iface t6-he default
	iface vpn-precision colobdry vpn sgo
	iface vpn-chiark sgo
	iface vpn-+ vpn
defhost roadstar
	iface eth0 dmz unsafe
	iface eth1 dmz unsafe
defhost jem
	iface eth0 dmz unsafe
	iface eth1 dmz unsafe
defhost artist
	hosttype router
	iface eth0 dmz unsafe untrusted
	iface eth1 dmz unsafe untrusted
	iface eth3 unsafe untrusted
defhost vampire
	hosttype router
	iface eth0.4 dmz unsafe untrusted safe vpn sgo colobdry
	iface eth0.5 dmz unsafe untrusted safe vpn sgo colobdry
	iface eth0.6 dmz unsafe safe untrusted vpn sgo colobdry
	iface eth0.7 unsafe untrusted vpn
	iface vpn-precision colobdry vpn sgo
	iface vpn-chiark sgo
	iface vpn-+ vpn
defhost ibanez
	iface br-dmz dmz unsafe
	iface br-unsafe unsafe
defhost orange
	iface wlan0 untrusted
	iface vpn-radius unsafe

defhost gibson
	hosttype client
	iface eth0 unsafe

## Colocated networks.
defnet jump trusted
	addr 212.13.198.64/28 2001:ba8:0:1d9::/64
	via colohub
defnet colo trusted
	addr 172.29.199.176/28 2001:ba8:1d9:2::/64
	via colohub
defnet colohub virtual
	via colobdry jump colo
defnet colobdry virtual
	via colohub hub
defnet iodine untrusted
	addr 172.29.198.128/28
	via colohub

## Colocated hosts.
defhost fender
	iface br-jump jump colo
	iface br-colo jump colo
defhost precision
	hosttype router
	iface eth0 jump colo vpn sgo
	iface eth1 jump colo vpn sgo
	iface vpn-mango binswood
	iface vpn-radius housebdry vpn sgo
	iface vpn-chiark sgo
	iface vpn-+ vpn
defhost telecaster
	iface eth0 jump colo
	iface eth1 jump colo
defhost stratocaster
	iface eth0 jump colo
	iface eth1 jump colo
defhost jaguar
	iface eth0 jump
defhost jazz
	hosttype router
	iface eth0 jump colo vpn
	iface eth1 jump colo vpn
	iface dns0 iodine
	iface vpn-+ vpn

## Other networks.
defnet hub virtual
	via housebdry colobdry
defnet sgo noloop
	addr !172.29.198.0/23
	addr 10.0.0.0/8
	addr 172.16.0.0/12
	addr 192.168.0.0/16
	via househub colohub
defnet vpn safe
	addr 172.29.199.128/27 2001:ba8:1d9:6000::/64
	via househub colohub
	host crybaby 1 ::1:1
	host terror 2 ::2:1
	host orange 3 ::3:1
	host haze 4 ::4:1
defnet anycast trusted
	addr 172.29.199.224/27 2001:ba8:1d9:0::/64
	via dmz unsafe safe untrusted jump colo vpn
defnet default untrusted
	addr 62.49.204.144/28 2001:470:1f09:1b98::/64
	addr 212.13.198.64/28 2001:ba8:0:1d9::/64
	addr 2001:ba8:1d9::/48 #temporary
	via dmz unsafe untrusted jump colo

## Satellite networks.
defnet binswood noloop
	addr 10.165.27.0/24
	via colohub

defhost mango
	hosttype router
	iface eth0 binswood default
	iface vpn-precision colo

m4_divert(80)m4_dnl
###--------------------------------------------------------------------------
### Connection tracking helper modules.

for i in ftp; do
  modprobe nf_conntrack_$i
done

m4_divert(80)m4_dnl
###--------------------------------------------------------------------------
### Special forwarding exemptions.

case $forward in
  1)

    ## Only allow these packets if they're not fragmented.  (Don't trust safe
    ## hosts's fragment reassembly to be robust against malicious fragments.)
    ## There's a hideous bug in iptables 1.4.11.1 which botches the meaning
    ## of `! -f', so we do the negation using early return from a subchain.
    clearchain fwd-spec-nofrag
    run iptables -A fwd-spec-nofrag -j RETURN --fragment
    run ip6tables -A fwd-spec-nofrag -j RETURN \
	    -m ipv6header --soft --header frag
    run ip46tables -A FORWARD -j fwd-spec-nofrag

    ## Allow ping from safe/noloop to untrusted networks.
    run iptables -A fwd-spec-nofrag -j ACCEPT \
	    -p icmp --icmp-type echo-request \
	    -m mark --mark $to_untrusted/$MASK_TO
    run iptables -A fwd-spec-nofrag -j ACCEPT \
	    -p icmp --icmp-type echo-reply \
	    -m mark --mark $from_untrusted/$MASK_FROM \
	    -m state --state ESTABLISHED
    run ip6tables -A fwd-spec-nofrag -j ACCEPT \
	    -p icmpv6 --icmpv6-type echo-request \
	    -m mark --mark $to_untrusted/$MASK_TO
    run ip6tables -A fwd-spec-nofrag -j ACCEPT \
	    -p icmpv6 --icmpv6-type echo-reply \
	    -m mark --mark $from_untrusted/$MASK_FROM \
	    -m state --state ESTABLISHED

    ## Allow SSH from safe/noloop to untrusted networks.
    run ip46tables -A fwd-spec-nofrag -j ACCEPT \
	    -p tcp --destination-port $port_ssh \
	    -m mark --mark $to_untrusted/$MASK_TO
    run ip46tables -A fwd-spec-nofrag -j ACCEPT \
	    -p tcp --source-port $port_ssh \
	    -m mark --mark $from_untrusted/$MASK_FROM \
	    -m state --state ESTABLISHED

    ;;
esac

m4_divert(80)m4_dnl
###--------------------------------------------------------------------------
### Kill things we don't understand properly.
###
### I don't like having to do this, but since I don't know how to do proper
### multicast filtering, I'm just going to ban it from being forwarded.

errorchain poorly-understood REJECT

## Ban multicast destination addresses in forwarding.
case $forward in
  1)
    run iptables -A FORWARD -g poorly-understood \
	    -d 224.0.0.0/4
    run ip6tables -A FORWARD -g poorly-understood \
	    -d ff::/8
    ;;
esac

m4_divert(84)m4_dnl
###--------------------------------------------------------------------------
### Locally-bound packet inspection.

clearchain inbound

## Track connections.
commonrules inbound
conntrack inbound

## Allow incoming bootp.  Bootp won't be forwarded, so this is obviously a
## local request.
run iptables -A inbound -j ACCEPT \
	-s 0.0.0.0 -d 255.255.255.255 \
	-p udp --source-port $port_bootpc --destination-port $port_bootps
run iptables -A inbound -j ACCEPT \
	-s 172.29.198.0/23 \
	-p udp --source-port $port_bootpc --destination-port $port_bootps

## Allow incoming ping.  This is the only ICMP left.
run ip46tables -A inbound -j ACCEPT -p icmp

m4_divert(88)m4_dnl
## Allow unusual things.
openports inbound

## Inspect inbound packets from untrusted sources.
run ip46tables -A inbound -j forbidden
run ip46tables -A INPUT -m mark --mark $from_untrusted/$MASK_FROM -g inbound

## Otherwise process as indicated by the mark.
for i in $inchains; do
  run ip46tables -A $i -m mark ! --mark 0/$MASK_MASK -j ACCEPT
done

m4_divert(-1)
###----- That's all, folks --------------------------------------------------
Commit	Line	Data
775bd287	1	### --sh--
bfdc045d MW	2	###
	3	### Local firewall configuration
	4	###
	5	### (c) 2008 Mark Wooding
	6	###
	7
	8	###----- Licensing notice ---------------------------------------------------
	9	###
	10	### This program is free software; you can redistribute it and/or modify
	11	### it under the terms of the GNU General Public License as published by
	12	### the Free Software Foundation; either version 2 of the License, or
	13	### (at your option) any later version.
	14	###
	15	### This program is distributed in the hope that it will be useful,
	16	### but WITHOUT ANY WARRANTY; without even the implied warranty of
	17	### MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	18	### GNU General Public License for more details.
	19	###
	20	### You should have received a copy of the GNU General Public License
	21	### along with this program; if not, write to the Free Software Foundation,
	22	### Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
	23
	24	###--------------------------------------------------------------------------
335b2afe MW	25	### Local configuration.
	26
	27	m4_divert(6)m4_dnl
	28	## Default NTP servers.
	29	defconf(ntp_servers,
	30	"158.152.1.76 158.152.1.204 194.159.253.2 195.173.57.232")
	31
	32	m4_divert(-1)
	33	###--------------------------------------------------------------------------
bfdc045d MW	34	### Packet classification.
bfdc045d MW	35
36e36cc7 MW	36	## IPv4 addressing.
	37	##
	38	## There are two small blocks of publicly routable IPv4 addresses, and a
	39	## block of RFC1918 private-use addresses allocated from the Cambridge G-RIN.
	40	## The former are as follows.
	41	##
	42	## 62.49.204.144/28
	43	## House border network (dmz). We have all of these, but .145
	44	## is reserved for the router.
	45	##
	46	## 212.13.18.64/28
	47	## Jump colocated network (jump). .65--68 are used by Jump
	48	## network infrastructure; we get the rest.
	49	##
	50	## The latter is the block 172.29.196.0/22. Currently the low half is
	51	## unallocated (and may be returned to the G-RIN); the remaining addresses
	52	## are allocated as follows.
	53	##
	54	## 172.29.198.0/24 Untrusted networks.
	55	## .0/25 house wireless net
	56	## .128/28 iodine (IP-over-DNS) network
	57	##
	58	## 172.29.199.0/24 Trusted networks.
	59	## .0/25 house wired network
	60	## .128/27 mobile VPN hosts
	61	## .160/28 reserved, except .160/30 allocated for ITS
	62	## .176/28 internal colocated network
	63	## .192/27 house safe network
	64	## .224/27 anycast services
	65
	66	## IPv6 addressing.
	67	##
	68	## There are five blocks of publicly routable IPv6 addresses, though some of
	69	## them aren't very interesting. The ranges are as follows.
	70	##
	71	## 2001:470:1f08:1b98::/64
	72	## Hurricane Electric tunnel network: only :1 (HE) and :2
	73	## (radius) are used.
	74	##
	75	## 2001:470:1f09:1b98::/64
	76	## House border network (dmz).
	77	##
	78	## 2001:470:9740::/48
	79	## Main house range. See below for allocation policy.
	80	##
	81	## 2001:ba8:0:1d9::/64
	82	## Jump border network (jump): :1 is the router (supplied by
	83	## Jump); other addresses are ours.
	84	##
	85	## 2001:ba8:1d9::/48
	86	## Main colocated range. See below for allocation policy.
	87	##
	88	## Addresses in the /64 networks are simply allocated in ascending order.
	89	## The /48s are split into /64s by appending a 16-bit network number. The
	90	## top nibble of the network number classifies the network, as follows.
	91	##
	92	## 8xxx Untrusted
2caaca79	93	## 6xxx Virtual, safe
36e36cc7 MW	94	## 4xxx Safe
	95	## 0xxx Unsafe, trusted
	96	##
	97	## These have been chosen so that network properties can be deduced by
	98	## inspecting bits of the network number:
	99	##
	100	## Bit 15 If set, the network is untrusted; otherwise it is trusted.
	101	## Bit 14 If set, the network is safe; otherwise it is unsafe.
	102	##
	103	## Finally, the low-order nibbles identify the site.
	104	##
	105	## 0 No specific site: mobile VPN endpoints or anycast addresses.
	106	## 1 House.
	107	## 2 Jump colocation.
	108	##
	109	## Usually site-0 networks are allocated from the Jump range to improve
	110	## expected performance from/to external sites which don't engage in our
	111	## dynamic routing protocols.
	112
bfdc045d MW	113	## Define the available network classes.
bfdc045d MW	114	m4_divert(42)m4_dnl
951e7943 MW	115	defnetclass untrusted untrusted trusted mcast
	116	defnetclass trusted untrusted trusted safe noloop mcast
	117	defnetclass safe trusted safe noloop mcast
	118	defnetclass noloop trusted safe mcast
	119
44f95827 MW	120	defnetclass link
44f95827 MW	121	defnetclass mcast
a4d8cae3	122	m4_divert(-1)
bfdc045d	123
a4d8cae3	124	m4_divert(26)m4_dnl
bfdc045d MW	125	###--------------------------------------------------------------------------
	126	### Network layout.
	127
beb4f0ee MW	128	## House networks.
beb4f0ee MW	129	defnet dmz trusted
b9e891b5	130	addr 62.49.204.144/28 2001:470:1f09:1b98::/64
17a45245	131	via unsafe untrusted
beb4f0ee	132	defnet unsafe trusted
b9e891b5	133	addr 172.29.199.0/25 2001:470:9740:1::/64
17a45245	134	via househub
beb4f0ee	135	defnet safe safe
216285e1	136	addr 172.29.199.192/27 2001:470:9740:4001::/64
17a45245	137	via househub
beb4f0ee	138	defnet untrusted untrusted
b9e891b5	139	addr 172.29.198.0/25 2001:470:9740:8001::/64
17a45245	140	via househub
bfdc045d	141
beb4f0ee	142	defnet househub virtual
17a45245	143	via housebdry dmz unsafe safe untrusted
beb4f0ee	144	defnet housebdry virtual
17a45245	145	via househub hub
beb4f0ee MW	146
	147	## House hosts.
	148	defhost radius
4eb9f4df	149	hosttype router
68f0829f MW	150	iface eth0 dmz unsafe safe untrusted vpn sgo colobdry default
68f0829f MW	151	iface eth1 dmz unsafe safe untrusted vpn sgo colobdry default
960a9996	152	iface eth2 dmz unsafe safe untrusted vpn sgo colobdry
83cc1e6c	153	iface eth3 unsafe untrusted vpn default
8506ff83	154	iface ppp0 default
a7e48c06	155	iface t6-he default
68f0829f MW	156	iface vpn-precision colobdry vpn sgo
	157	iface vpn-chiark sgo
	158	iface vpn-+ vpn
beb4f0ee	159	defhost roadstar
ce6434f7 MW	160	iface eth0 dmz unsafe
ce6434f7 MW	161	iface eth1 dmz unsafe
beb4f0ee	162	defhost jem
ce6434f7 MW	163	iface eth0 dmz unsafe
ce6434f7 MW	164	iface eth1 dmz unsafe
beb4f0ee	165	defhost artist
564c6939	166	hosttype router
490003e4 MW	167	iface eth0 dmz unsafe untrusted
490003e4 MW	168	iface eth1 dmz unsafe untrusted
83cc1e6c	169	iface eth3 unsafe untrusted
beb4f0ee	170	defhost vampire
4eb9f4df	171	hosttype router
2b17ac87 MW	172	iface eth0.4 dmz unsafe untrusted safe vpn sgo colobdry
	173	iface eth0.5 dmz unsafe untrusted safe vpn sgo colobdry
	174	iface eth0.6 dmz unsafe safe untrusted vpn sgo colobdry
83cc1e6c	175	iface eth0.7 unsafe untrusted vpn
68f0829f	176	iface vpn-precision colobdry vpn sgo
ebaa31a7 MW	177	iface vpn-chiark sgo
ebaa31a7 MW	178	iface vpn-+ vpn
beb4f0ee	179	defhost ibanez
06ff8082	180	iface br-dmz dmz unsafe
beb4f0ee	181	iface br-unsafe unsafe
6fd217ae MW	182	defhost orange
	183	iface wlan0 untrusted
	184	iface vpn-radius unsafe
beb4f0ee MW	185
beb4f0ee MW	186	defhost gibson
4eb9f4df	187	hosttype client
beb4f0ee MW	188	iface eth0 unsafe
	189
	190	## Colocated networks.
	191	defnet jump trusted
b9e891b5	192	addr 212.13.198.64/28 2001:ba8:0:1d9::/64
17a45245	193	via colohub
beb4f0ee	194	defnet colo trusted
b9e891b5	195	addr 172.29.199.176/28 2001:ba8:1d9:2::/64
17a45245	196	via colohub
beb4f0ee	197	defnet colohub virtual
9853a66d	198	via colobdry jump colo
beb4f0ee	199	defnet colobdry virtual
17a45245	200	via colohub hub
148d527c MW	201	defnet iodine untrusted
148d527c MW	202	addr 172.29.198.128/28
17a45245	203	via colohub
beb4f0ee MW	204
	205	## Colocated hosts.
	206	defhost fender
ce6434f7 MW	207	iface br-jump jump colo
ce6434f7 MW	208	iface br-colo jump colo
beb4f0ee	209	defhost precision
4eb9f4df	210	hosttype router
560ae309 MW	211	iface eth0 jump colo vpn sgo
560ae309 MW	212	iface eth1 jump colo vpn sgo
1fd9cef9	213	iface vpn-mango binswood
68f0829f	214	iface vpn-radius housebdry vpn sgo
ebaa31a7 MW	215	iface vpn-chiark sgo
ebaa31a7 MW	216	iface vpn-+ vpn
beb4f0ee	217	defhost telecaster
ce6434f7 MW	218	iface eth0 jump colo
ce6434f7 MW	219	iface eth1 jump colo
beb4f0ee	220	defhost stratocaster
ce6434f7 MW	221	iface eth0 jump colo
ce6434f7 MW	222	iface eth1 jump colo
b4654819 MW	223	defhost jaguar
b4654819 MW	224	iface eth0 jump
beb4f0ee	225	defhost jazz
560ae309 MW	226	hosttype router
	227	iface eth0 jump colo vpn
	228	iface eth1 jump colo vpn
148d527c	229	iface dns0 iodine
560ae309	230	iface vpn-+ vpn
beb4f0ee MW	231
	232	## Other networks.
	233	defnet hub virtual
17a45245	234	via housebdry colobdry
ebaa31a7 MW	235	defnet sgo noloop
	236	addr !172.29.198.0/23
	237	addr 10.0.0.0/8
	238	addr 172.16.0.0/12
	239	addr 192.168.0.0/16
17a45245	240	via househub colohub
7dff2754 MW	241	defnet vpn safe
7dff2754 MW	242	addr 172.29.199.128/27 2001:ba8:1d9:6000::/64
17a45245	243	via househub colohub
eec061c0 MW	244	host crybaby 1 ::1:1
	245	host terror 2 ::2:1
	246	host orange 3 ::3:1
a28edce0	247	host haze 4 ::4:1
c68b8ecc MW	248	defnet anycast trusted
c68b8ecc MW	249	addr 172.29.199.224/27 2001:ba8:1d9:0::/64
17a45245	250	via dmz unsafe safe untrusted jump colo vpn
beb4f0ee	251	defnet default untrusted
b9e891b5 MW	252	addr 62.49.204.144/28 2001:470:1f09:1b98::/64
	253	addr 212.13.198.64/28 2001:ba8:0:1d9::/64
	254	addr 2001:ba8:1d9::/48 #temporary
17a45245	255	via dmz unsafe untrusted jump colo
1ee6211d	256
1fd9cef9 MW	257	## Satellite networks.
	258	defnet binswood noloop
	259	addr 10.165.27.0/24
	260	via colohub
	261
31c0a107 MW	262	defhost mango
	263	hosttype router
	264	iface eth0 binswood default
	265	iface vpn-precision colo
	266
a4d8cae3	267	m4_divert(80)m4_dnl
bfdc045d	268	###--------------------------------------------------------------------------
5c5fcd73 MW	269	### Connection tracking helper modules.
	270
	271	for i in ftp; do
	272	modprobe nf_conntrack_$i
	273	done
	274
	275	m4_divert(80)m4_dnl
	276	###--------------------------------------------------------------------------
bfdc045d MW	277	### Special forwarding exemptions.
bfdc045d MW	278
78af294c MW	279	case $forward in
	280	1)
	281
	282	## Only allow these packets if they're not fragmented. (Don't trust safe
	283	## hosts's fragment reassembly to be robust against malicious fragments.)
	284	## There's a hideous bug in iptables 1.4.11.1 which botches the meaning
	285	## of `! -f', so we do the negation using early return from a subchain.
	286	clearchain fwd-spec-nofrag
	287	run iptables -A fwd-spec-nofrag -j RETURN --fragment
	288	run ip6tables -A fwd-spec-nofrag -j RETURN \
	289	-m ipv6header --soft --header frag
87bf1592	290	run ip46tables -A FORWARD -j fwd-spec-nofrag
78af294c MW	291
	292	## Allow ping from safe/noloop to untrusted networks.
	293	run iptables -A fwd-spec-nofrag -j ACCEPT \
	294	-p icmp --icmp-type echo-request \
	295	-m mark --mark $to_untrusted/$MASK_TO
	296	run iptables -A fwd-spec-nofrag -j ACCEPT \
	297	-p icmp --icmp-type echo-reply \
	298	-m mark --mark $from_untrusted/$MASK_FROM \
	299	-m state --state ESTABLISHED
	300	run ip6tables -A fwd-spec-nofrag -j ACCEPT \
8b021091	301	-p icmpv6 --icmpv6-type echo-request \
78af294c MW	302	-m mark --mark $to_untrusted/$MASK_TO
78af294c MW	303	run ip6tables -A fwd-spec-nofrag -j ACCEPT \
8b021091	304	-p icmpv6 --icmpv6-type echo-reply \
78af294c MW	305	-m mark --mark $from_untrusted/$MASK_FROM \
	306	-m state --state ESTABLISHED
	307
	308	## Allow SSH from safe/noloop to untrusted networks.
cbbd5e39	309	run ip46tables -A fwd-spec-nofrag -j ACCEPT \
78af294c MW	310	-p tcp --destination-port $port_ssh \
78af294c MW	311	-m mark --mark $to_untrusted/$MASK_TO
cbbd5e39	312	run ip46tables -A fwd-spec-nofrag -j ACCEPT \
78af294c MW	313	-p tcp --source-port $port_ssh \
	314	-m mark --mark $from_untrusted/$MASK_FROM \
	315	-m state --state ESTABLISHED
	316
	317	;;
	318	esac
	319
a4d8cae3	320	m4_divert(80)m4_dnl
ade2c052 MW	321	###--------------------------------------------------------------------------
	322	### Kill things we don't understand properly.
	323	###
	324	### I don't like having to do this, but since I don't know how to do proper
	325	### multicast filtering, I'm just going to ban it from being forwarded.
	326
	327	errorchain poorly-understood REJECT
	328
	329	## Ban multicast destination addresses in forwarding.
78af294c MW	330	case $forward in
	331	1)
	332	run iptables -A FORWARD -g poorly-understood \
	333	-d 224.0.0.0/4
	334	run ip6tables -A FORWARD -g poorly-understood \
	335	-d ff::/8
	336	;;
	337	esac
ade2c052	338
a4d8cae3	339	m4_divert(84)m4_dnl
bfdc045d MW	340	###--------------------------------------------------------------------------
	341	### Locally-bound packet inspection.
	342
	343	clearchain inbound
	344
	345	## Track connections.
ecdca131	346	commonrules inbound
bfdc045d MW	347	conntrack inbound
	348
	349	## Allow incoming bootp. Bootp won't be forwarded, so this is obviously a
	350	## local request.
	351	run iptables -A inbound -j ACCEPT \
	352	-s 0.0.0.0 -d 255.255.255.255 \
	353	-p udp --source-port $port_bootpc --destination-port $port_bootps
	354	run iptables -A inbound -j ACCEPT \
	355	-s 172.29.198.0/23 \
	356	-p udp --source-port $port_bootpc --destination-port $port_bootps
	357
	358	## Allow incoming ping. This is the only ICMP left.
0291d6d5	359	run ip46tables -A inbound -j ACCEPT -p icmp
bfdc045d MW	360
	361	m4_divert(88)m4_dnl
	362	## Allow unusual things.
	363	openports inbound
	364
	365	## Inspect inbound packets from untrusted sources.
0291d6d5 MW	366	run ip46tables -A inbound -j forbidden
0291d6d5 MW	367	run ip46tables -A INPUT -m mark --mark $from_untrusted/$MASK_FROM -g inbound
bfdc045d MW	368
bfdc045d MW	369	## Otherwise process as indicated by the mark.
f0033e07 MW	370	for i in $inchains; do
	371	run ip46tables -A $i -m mark ! --mark 0/$MASK_MASK -j ACCEPT
	372	done
bfdc045d MW	373
	374	m4_divert(-1)
	375	###----- That's all, folks --------------------------------------------------