bcp38: migrate to nftables

Signed-off-by: Stefan Brusch <ne20002@gmx.ch>
(cherry picked from commit 471ffdd98c)
This commit is contained in:
Stefan Brusch 2022-11-15 16:26:38 +01:00 committed by Tianling Shen
parent fd3e15543e
commit 20d5a2216d
No known key found for this signature in database
GPG Key ID: 6850B6345C862176
3 changed files with 54 additions and 49 deletions

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@ -7,7 +7,7 @@ include $(TOPDIR)/rules.mk
PKG_NAME:=bcp38
PKG_VERSION:=5
PKG_RELEASE:=6
PKG_RELEASE:=$(AUTORELEASE)
PKG_LICENCE:=GPL-3.0-or-later
include $(INCLUDE_DIR)/package.mk
@ -19,7 +19,6 @@ define Package/bcp38
TITLE:=BCP38 compliance
URL:=https://github.com/dtaht/ceropackages-3.10
MAINTAINER:=Toke Høiland-Jørgensen <toke@toke.dk>
DEPENDS:=+ipset
PKGARCH:=all
endef
@ -27,7 +26,7 @@ define Package/bcp38/description
bcp38 implements IETF BCP38 for home routers.
See https://tools.ietf.org/html/bcp38.
This package provides BCP38 for IPv4 only - IPv6 uses source
This package provides BCP38 for IPv4 only - IPv6 uses source
specific default routes, so no firewall configuration is needed.
endef

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@ -5,8 +5,6 @@ uci -q batch <<-EOT
set firewall.bcp38=include
set firewall.bcp38.type=script
set firewall.bcp38.path=/usr/lib/bcp38/run.sh
set firewall.bcp38.family=IPv4
set firewall.bcp38.reload=1
commit firewall
EOT

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@ -9,8 +9,12 @@
# Author: Toke Høiland-Jørgensen <toke@toke.dk>
STOP=$1
IPSET_NAME=bcp38-ipv4
IPTABLES_CHAIN=BCP38
TABLE=bcp38
FAMILY=ip
MATCHSET=bcp38-match
NOMATCHSET=bcp38-nomatch
CHAIN=bcp38
. /lib/functions.sh
@ -21,84 +25,88 @@ add_bcp38_rule()
local subnet="$1"
local action="$2"
if [ "$action" == "nomatch" ]; then
ipset add "$IPSET_NAME" "$subnet" nomatch
else
ipset add "$IPSET_NAME" "$subnet"
fi
setname="$MATCHSET"
[ "$action" == "nomatch" ] && setname="$NOMATCHSET"
nft add element "$FAMILY" "$TABLE" "$setname" { "$subnet" }
}
detect_upstream()
detect_upstream_subnet()
{
local interface="$1"
subnets=$(ip route show dev "$interface" | grep 'scope link' | awk '{print $1}')
for subnet in $subnets; do
# ipset test doesn't work for subnets, so strip out the subnet part
# and test for that; add as exception if there's a match
addr=$(echo $subnet | sed 's|/[0-9]\+$||')
ipset test "$IPSET_NAME" $addr 2>/dev/null && add_bcp38_rule $subnet nomatch
#test for that; add as exception if there's a match
nft get element "$FAMILY" "$TABLE" "$MATCHSET" { $subnet } >/dev/null 2>/dev/null && add_bcp38_rule $subnet nomatch
done
}
run() {
local section="$1"
local enabled
local section="$1"
local enabled
local interface
local priority
local detect_upstream
config_get_bool enabled "$section" enabled 0
config_get interface "$section" interface
config_get detect_upstream "$section" detect_upstream
config_get priority "$section" priority "2"
if [ "$enabled" -eq "1" -a -n "$interface" -a -z "$STOP" ] ; then
setup_ipset
setup_iptables "$interface"
setup_table
setup_sets
setup_chains "$interface" "$priority"
config_list_foreach "$section" match add_bcp38_rule match
config_list_foreach "$section" nomatch add_bcp38_rule nomatch
[ "$detect_upstream" -eq "1" ] && detect_upstream "$interface"
[ "$detect_upstream" -eq "1" ] && detect_upstream_subnet "$interface"
fi
exit 0
}
setup_ipset()
setup_table()
{
ipset create "$IPSET_NAME" hash:net family ipv4
ipset flush "$IPSET_NAME"
nft add table "$FAMILY" "$TABLE"
}
setup_iptables()
setup_sets()
{
#create and flush sets
nft add set "$FAMILY" "$TABLE" "$MATCHSET" '{ type ipv4_addr; flags interval; }'
nft flush set "$FAMILY" "$TABLE" "$MATCHSET"
nft add set "$FAMILY" "$TABLE" "$NOMATCHSET" '{ type ipv4_addr; flags interval; }'
nft flush set "$FAMILY" "$TABLE" "$NOMATCHSET"
}
setup_chains()
{
local interface="$1"
iptables -N "$IPTABLES_CHAIN" 2>/dev/null
iptables -F "$IPTABLES_CHAIN" 2>/dev/null
local priority="$2"
iptables -I output_rule -m conntrack --ctstate NEW -j "$IPTABLES_CHAIN"
iptables -I input_rule -m conntrack --ctstate NEW -j "$IPTABLES_CHAIN"
iptables -I forwarding_rule -m conntrack --ctstate NEW -j "$IPTABLES_CHAIN"
nft add chain "$FAMILY" "$TABLE" "$CHAIN" 2>/dev/null
nft flush chain "$FAMILY" "$TABLE" "$CHAIN" 2>/dev/null
# always accept DHCP traffic
iptables -A "$IPTABLES_CHAIN" -p udp --dport 67:68 --sport 67:68 -j RETURN
iptables -A "$IPTABLES_CHAIN" -o "$interface" -m set --match-set "$IPSET_NAME" dst -j REJECT --reject-with icmp-net-unreachable
iptables -A "$IPTABLES_CHAIN" -i "$interface" -m set --match-set "$IPSET_NAME" src -j DROP
nft add rule "$FAMILY" "$TABLE" "$CHAIN" udp dport {67,68} udp sport {67,68} counter return comment \"always accept DHCP traffic\"
nft add rule "$FAMILY" "$TABLE" "$CHAIN" oifname $interface ip daddr @"$MATCHSET" ip daddr != @"$NOMATCHSET" counter reject with icmp type host-unreachable
nft add rule "$FAMILY" "$TABLE" "$CHAIN" iifname $interface ip saddr @"$MATCHSET" ip saddr != @"$NOMATCHSET" counter drop
nft add chain "$FAMILY" "$TABLE" input "{ type filter hook input priority $priority; policy accept; comment \"bcp38 filter\"; }"
nft add chain "$FAMILY" "$TABLE" forward "{ type filter hook forward priority $priority; policy accept; comment \"bcp38 filter\"; }"
nft add chain "$FAMILY" "$TABLE" output "{ type filter hook output priority $priority; policy accept; comment \"bcp38 filter\"; }"
nft insert rule "$FAMILY" "$TABLE" input ct state new jump "$CHAIN"
nft insert rule "$FAMILY" "$TABLE" forward ct state new jump "$CHAIN"
nft insert rule "$FAMILY" "$TABLE" output ct state new jump "$CHAIN"
}
destroy_ipset()
destroy_table()
{
ipset flush "$IPSET_NAME" 2>/dev/null
ipset destroy "$IPSET_NAME" 2>/dev/null
if [ "$TABLE" != "fw4" ]; then
#as of kernel 3.18 we can delete a table without need to flush it
nft delete table "$FAMILY" "$TABLE" 2>/dev/null
fi
}
destroy_iptables()
{
iptables -D output_rule -m conntrack --ctstate NEW -j "$IPTABLES_CHAIN" 2>/dev/null
iptables -D input_rule -m conntrack --ctstate NEW -j "$IPTABLES_CHAIN" 2>/dev/null
iptables -D forwarding_rule -m conntrack --ctstate NEW -j "$IPTABLES_CHAIN" 2>/dev/null
iptables -F "$IPTABLES_CHAIN" 2>/dev/null
iptables -X "$IPTABLES_CHAIN" 2>/dev/null
}
destroy_iptables
destroy_ipset
destroy_table
config_foreach run bcp38
exit 0