Commit f8ea4a19 authored by Jakub Kicinski's avatar Jakub Kicinski
Browse files

Merge branch 'l3mdev-icmp-error-route-lookup-fixes' 

Mathieu Desnoyers says:

====================
l3mdev icmp error route lookup fixes

Here is a series of fixes for ipv4 and ipv6 which ensure the route
lookup is performed on the right routing table in VRF configurations
when sending TTL expired icmp errors (useful for traceroute).

It includes tests for both ipv4 and ipv6.

These fixes address specifically address the code paths involved in
sending TTL expired icmp errors. As detailed in the individual commit
messages, those fixes do not address similar icmp errors related to
network namespaces and unreachable / fragmentation needed messages,
which appear to use different code paths.
====================

Link: https://lore.kernel.org/r/20201012145016.2023-1-mathieu.desnoyers@efficios.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parents 1e40d75e 1a017276

net/ipv4/icmp.c

+21 −2
Original line number Diff line number Diff line
@@ -457,6 +457,23 @@ out_bh_enable: 
	local_bh_enable();

}



/*

 * The device used for looking up which routing table to use for sending an ICMP

 * error is preferably the source whenever it is set, which should ensure the

 * icmp error can be sent to the source host, else lookup using the routing

 * table of the destination device, else use the main routing table (index 0).

 */

static struct net_device *icmp_get_route_lookup_dev(struct sk_buff *skb)

{

	struct net_device *route_lookup_dev = NULL;



	if (skb->dev)

		route_lookup_dev = skb->dev;

	else if (skb_dst(skb))

		route_lookup_dev = skb_dst(skb)->dev;

	return route_lookup_dev;

}



static struct rtable *icmp_route_lookup(struct net *net,

					struct flowi4 *fl4,

					struct sk_buff *skb_in,
@@ -465,6 +482,7 @@ static struct rtable *icmp_route_lookup(struct net *net, 
					int type, int code,

					struct icmp_bxm *param)

{

	struct net_device *route_lookup_dev;

	struct rtable *rt, *rt2;

	struct flowi4 fl4_dec;

	int err;
@@ -479,7 +497,8 @@ static struct rtable *icmp_route_lookup(struct net *net, 
	fl4->flowi4_proto = IPPROTO_ICMP;

	fl4->fl4_icmp_type = type;

	fl4->fl4_icmp_code = code;

	fl4->flowi4_oif = l3mdev_master_ifindex(skb_dst(skb_in)->dev);

	route_lookup_dev = icmp_get_route_lookup_dev(skb_in);

	fl4->flowi4_oif = l3mdev_master_ifindex(route_lookup_dev);



	security_skb_classify_flow(skb_in, flowi4_to_flowi(fl4));

	rt = ip_route_output_key_hash(net, fl4, skb_in);
@@ -503,7 +522,7 @@ static struct rtable *icmp_route_lookup(struct net *net, 
	if (err)

		goto relookup_failed;



	if (inet_addr_type_dev_table(net, skb_dst(skb_in)->dev,

	if (inet_addr_type_dev_table(net, route_lookup_dev,

				     fl4_dec.saddr) == RTN_LOCAL) {

		rt2 = __ip_route_output_key(net, &fl4_dec);

		if (IS_ERR(rt2))

net/ipv6/icmp.c

+5 −2
Original line number Diff line number Diff line
@@ -501,8 +501,11 @@ void icmp6_send(struct sk_buff *skb, u8 type, u8 code, __u32 info, 
	if (__ipv6_addr_needs_scope_id(addr_type)) {

		iif = icmp6_iif(skb);

	} else {

		dst = skb_dst(skb);

		iif = l3mdev_master_ifindex(dst ? dst->dev : skb->dev);

		/*

		 * The source device is used for looking up which routing table

		 * to use for sending an ICMP error.

		 */

		iif = l3mdev_master_ifindex(skb->dev);

	}



	/*

net/ipv6/ip6_output.c

+0 −2
Original line number Diff line number Diff line
@@ -468,8 +468,6 @@ int ip6_forward(struct sk_buff *skb) 
	 *	check and decrement ttl

	 */

	if (hdr->hop_limit <= 1) {

		/* Force OUTPUT device used as source address */

		skb->dev = dst->dev;

		icmpv6_send(skb, ICMPV6_TIME_EXCEED, ICMPV6_EXC_HOPLIMIT, 0);

		__IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);

tools/testing/selftests/net/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -19,6 +19,7 @@ TEST_PROGS += txtimestamp.sh 
TEST_PROGS += vrf-xfrm-tests.sh

TEST_PROGS += rxtimestamp.sh

TEST_PROGS += devlink_port_split.py

TEST_PROGS += vrf_route_leaking.sh

TEST_PROGS_EXTENDED := in_netns.sh

TEST_GEN_FILES =  socket nettest

TEST_GEN_FILES += psock_fanout psock_tpacket msg_zerocopy reuseport_addr_any

tools/testing/selftests/net/vrf_route_leaking.sh

0 → 100755
+626 −0
Original line number Diff line number Diff line 
#!/bin/bash

# SPDX-License-Identifier: GPL-2.0

#

# Copyright (c) 2019 David Ahern <dsahern@gmail.com>. All rights reserved.

# Copyright (c) 2020 Michael Jeanson <mjeanson@efficios.com>. All rights reserved.

#

# Requires CONFIG_NET_VRF, CONFIG_VETH, CONFIG_BRIDGE and CONFIG_NET_NS.

#

#

# Symmetric routing topology

#

#                     blue         red

# +----+              .253 +----+ .253              +----+

# | h1 |-------------------| r1 |-------------------| h2 |

# +----+ .1                +----+                .2 +----+

#         172.16.1/24                  172.16.2/24

#    2001:db8:16:1/64                  2001:db8:16:2/64

#

#

# Route from h1 to h2 and back goes through r1, incoming vrf blue has a route

# to the outgoing vrf red for the n2 network and red has a route back to n1.

# The red VRF interface has a MTU of 1400.

#

# The first test sends a ping with a ttl of 1 from h1 to h2 and parses the

# output of the command to check that a ttl expired error is received.

#

# The second test runs traceroute from h1 to h2 and parses the output to check

# for a hop on r1.

#

# The third test sends a ping with a packet size of 1450 from h1 to h2 and

# parses the output of the command to check that a fragmentation error is

# received.

#

#

# Asymmetric routing topology

#

# This topology represents a customer setup where the issue with icmp errors

# and VRF route leaking was initialy reported. The MTU test isn't done here

# because of the lack of a return route in the red VRF.

#

#                     blue         red

#                     .253 +----+ .253

#                     +----| r1 |----+

#                     |    +----+    |

# +----+              |              |              +----+

# | h1 |--------------+              +--------------| h2 |

# +----+ .1           |              |           .2 +----+

#         172.16.1/24 |    +----+    | 172.16.2/24

#    2001:db8:16:1/64 +----| r2 |----+ 2001:db8:16:2/64

#                     .254 +----+ .254

#

#

# Route from h1 to h2 goes through r1, incoming vrf blue has a route to the

# outgoing vrf red for the n2 network but red doesn't have a route back to n1.

# Route from h2 to h1 goes through r2.

#

# The objective is to check that the incoming vrf routing table is selected

# to send an ICMP error back to the source when the ttl of a packet reaches 1

# while it is forwarded between different vrfs.



VERBOSE=0

PAUSE_ON_FAIL=no

DEFAULT_TTYPE=sym



H1_N1=172.16.1.0/24

H1_N1_6=2001:db8:16:1::/64



H1_N1_IP=172.16.1.1

R1_N1_IP=172.16.1.253

R2_N1_IP=172.16.1.254



H1_N1_IP6=2001:db8:16:1::1

R1_N1_IP6=2001:db8:16:1::253

R2_N1_IP6=2001:db8:16:1::254



H2_N2=172.16.2.0/24

H2_N2_6=2001:db8:16:2::/64



H2_N2_IP=172.16.2.2

R1_N2_IP=172.16.2.253

R2_N2_IP=172.16.2.254



H2_N2_IP6=2001:db8:16:2::2

R1_N2_IP6=2001:db8:16:2::253

R2_N2_IP6=2001:db8:16:2::254



################################################################################

# helpers



log_section()

{

	echo

	echo "###########################################################################"

	echo "$*"

	echo "###########################################################################"

	echo

}



log_test()

{

	local rc=$1

	local expected=$2

	local msg="$3"



	if [ "${rc}" -eq "${expected}" ]; then

		printf "TEST: %-60s  [ OK ]\n" "${msg}"

		nsuccess=$((nsuccess+1))

	else

		ret=1

		nfail=$((nfail+1))

		printf "TEST: %-60s  [FAIL]\n" "${msg}"

		if [ "${PAUSE_ON_FAIL}" = "yes" ]; then

			echo

			echo "hit enter to continue, 'q' to quit"

			read -r a

			[ "$a" = "q" ] && exit 1

		fi

	fi

}



run_cmd()

{

	local cmd="$*"

	local out

	local rc



	if [ "$VERBOSE" = "1" ]; then

		echo "COMMAND: $cmd"

	fi



	# shellcheck disable=SC2086

	out=$(eval $cmd 2>&1)

	rc=$?

	if [ "$VERBOSE" = "1" ] && [ -n "$out" ]; then

		echo "$out"

	fi



	[ "$VERBOSE" = "1" ] && echo



	return $rc

}



run_cmd_grep()

{

	local grep_pattern="$1"

	shift

	local cmd="$*"

	local out

	local rc



	if [ "$VERBOSE" = "1" ]; then

		echo "COMMAND: $cmd"

	fi



	# shellcheck disable=SC2086

	out=$(eval $cmd 2>&1)

	if [ "$VERBOSE" = "1" ] && [ -n "$out" ]; then

		echo "$out"

	fi



	echo "$out" | grep -q "$grep_pattern"

	rc=$?



	[ "$VERBOSE" = "1" ] && echo



	return $rc

}



################################################################################

# setup and teardown



cleanup()

{

	local ns



	for ns in h1 h2 r1 r2; do

		ip netns del $ns 2>/dev/null

	done

}



setup_vrf()

{

	local ns=$1



	ip -netns "${ns}" rule del pref 0

	ip -netns "${ns}" rule add pref 32765 from all lookup local

	ip -netns "${ns}" -6 rule del pref 0

	ip -netns "${ns}" -6 rule add pref 32765 from all lookup local

}



create_vrf()

{

	local ns=$1

	local vrf=$2

	local table=$3



	ip -netns "${ns}" link add "${vrf}" type vrf table "${table}"

	ip -netns "${ns}" link set "${vrf}" up

	ip -netns "${ns}" route add vrf "${vrf}" unreachable default metric 8192

	ip -netns "${ns}" -6 route add vrf "${vrf}" unreachable default metric 8192



	ip -netns "${ns}" addr add 127.0.0.1/8 dev "${vrf}"

	ip -netns "${ns}" -6 addr add ::1 dev "${vrf}" nodad

}



setup_sym()

{

	local ns



	# make sure we are starting with a clean slate

	cleanup



	#

	# create nodes as namespaces

	#

	for ns in h1 h2 r1; do

		ip netns add $ns

		ip -netns $ns link set lo up



		case "${ns}" in

		h[12]) ip netns exec $ns sysctl -q -w net.ipv6.conf.all.forwarding=0

		       ip netns exec $ns sysctl -q -w net.ipv6.conf.all.keep_addr_on_down=1

			;;

		r1)    ip netns exec $ns sysctl -q -w net.ipv4.ip_forward=1

		       ip netns exec $ns sysctl -q -w net.ipv6.conf.all.forwarding=1

		esac

	done



	#

	# create interconnects

	#

	ip -netns h1 link add eth0 type veth peer name r1h1

	ip -netns h1 link set r1h1 netns r1 name eth0 up



	ip -netns h2 link add eth0 type veth peer name r1h2

	ip -netns h2 link set r1h2 netns r1 name eth1 up



	#

	# h1

	#

	ip -netns h1 addr add dev eth0 ${H1_N1_IP}/24

	ip -netns h1 -6 addr add dev eth0 ${H1_N1_IP6}/64 nodad

	ip -netns h1 link set eth0 up



	# h1 to h2 via r1

	ip -netns h1    route add ${H2_N2} via ${R1_N1_IP} dev eth0

	ip -netns h1 -6 route add ${H2_N2_6} via "${R1_N1_IP6}" dev eth0



	#

	# h2

	#

	ip -netns h2 addr add dev eth0 ${H2_N2_IP}/24

	ip -netns h2 -6 addr add dev eth0 ${H2_N2_IP6}/64 nodad

	ip -netns h2 link set eth0 up



	# h2 to h1 via r1

	ip -netns h2 route add default via ${R1_N2_IP} dev eth0

	ip -netns h2 -6 route add default via ${R1_N2_IP6} dev eth0



	#

	# r1

	#

	setup_vrf r1

	create_vrf r1 blue 1101

	create_vrf r1 red 1102

	ip -netns r1 link set mtu 1400 dev eth1

	ip -netns r1 link set eth0 vrf blue up

	ip -netns r1 link set eth1 vrf red up

	ip -netns r1 addr add dev eth0 ${R1_N1_IP}/24

	ip -netns r1 -6 addr add dev eth0 ${R1_N1_IP6}/64 nodad

	ip -netns r1 addr add dev eth1 ${R1_N2_IP}/24

	ip -netns r1 -6 addr add dev eth1 ${R1_N2_IP6}/64 nodad



	# Route leak from blue to red

	ip -netns r1 route add vrf blue ${H2_N2} dev red

	ip -netns r1 -6 route add vrf blue ${H2_N2_6} dev red



	# Route leak from red to blue

	ip -netns r1 route add vrf red ${H1_N1} dev blue

	ip -netns r1 -6 route add vrf red ${H1_N1_6} dev blue





	# Wait for ip config to settle

	sleep 2

}



setup_asym()

{

	local ns



	# make sure we are starting with a clean slate

	cleanup



	#

	# create nodes as namespaces

	#

	for ns in h1 h2 r1 r2; do

		ip netns add $ns

		ip -netns $ns link set lo up



		case "${ns}" in

		h[12]) ip netns exec $ns sysctl -q -w net.ipv6.conf.all.forwarding=0

		       ip netns exec $ns sysctl -q -w net.ipv6.conf.all.keep_addr_on_down=1

			;;

		r[12]) ip netns exec $ns sysctl -q -w net.ipv4.ip_forward=1

		       ip netns exec $ns sysctl -q -w net.ipv6.conf.all.forwarding=1

		esac

	done



	#

	# create interconnects

	#

	ip -netns h1 link add eth0 type veth peer name r1h1

	ip -netns h1 link set r1h1 netns r1 name eth0 up



	ip -netns h1 link add eth1 type veth peer name r2h1

	ip -netns h1 link set r2h1 netns r2 name eth0 up



	ip -netns h2 link add eth0 type veth peer name r1h2

	ip -netns h2 link set r1h2 netns r1 name eth1 up



	ip -netns h2 link add eth1 type veth peer name r2h2

	ip -netns h2 link set r2h2 netns r2 name eth1 up



	#

	# h1

	#

	ip -netns h1 link add br0 type bridge

	ip -netns h1 link set br0 up

	ip -netns h1 addr add dev br0 ${H1_N1_IP}/24

	ip -netns h1 -6 addr add dev br0 ${H1_N1_IP6}/64 nodad

	ip -netns h1 link set eth0 master br0 up

	ip -netns h1 link set eth1 master br0 up



	# h1 to h2 via r1

	ip -netns h1    route add ${H2_N2} via ${R1_N1_IP} dev br0

	ip -netns h1 -6 route add ${H2_N2_6} via "${R1_N1_IP6}" dev br0



	#

	# h2

	#

	ip -netns h2 link add br0 type bridge

	ip -netns h2 link set br0 up

	ip -netns h2 addr add dev br0 ${H2_N2_IP}/24

	ip -netns h2 -6 addr add dev br0 ${H2_N2_IP6}/64 nodad

	ip -netns h2 link set eth0 master br0 up

	ip -netns h2 link set eth1 master br0 up



	# h2 to h1 via r2

	ip -netns h2 route add default via ${R2_N2_IP} dev br0

	ip -netns h2 -6 route add default via ${R2_N2_IP6} dev br0



	#

	# r1

	#

	setup_vrf r1

	create_vrf r1 blue 1101

	create_vrf r1 red 1102

	ip -netns r1 link set mtu 1400 dev eth1

	ip -netns r1 link set eth0 vrf blue up

	ip -netns r1 link set eth1 vrf red up

	ip -netns r1 addr add dev eth0 ${R1_N1_IP}/24

	ip -netns r1 -6 addr add dev eth0 ${R1_N1_IP6}/64 nodad

	ip -netns r1 addr add dev eth1 ${R1_N2_IP}/24

	ip -netns r1 -6 addr add dev eth1 ${R1_N2_IP6}/64 nodad



	# Route leak from blue to red

	ip -netns r1 route add vrf blue ${H2_N2} dev red

	ip -netns r1 -6 route add vrf blue ${H2_N2_6} dev red



	# No route leak from red to blue



	#

	# r2

	#

	ip -netns r2 addr add dev eth0 ${R2_N1_IP}/24

	ip -netns r2 -6 addr add dev eth0 ${R2_N1_IP6}/64 nodad

	ip -netns r2 addr add dev eth1 ${R2_N2_IP}/24

	ip -netns r2 -6 addr add dev eth1 ${R2_N2_IP6}/64 nodad



	# Wait for ip config to settle

	sleep 2

}



check_connectivity()

{

	ip netns exec h1 ping -c1 -w1 ${H2_N2_IP} >/dev/null 2>&1

	log_test $? 0 "Basic IPv4 connectivity"

	return $?

}



check_connectivity6()

{

	ip netns exec h1 "${ping6}" -c1 -w1 ${H2_N2_IP6} >/dev/null 2>&1

	log_test $? 0 "Basic IPv6 connectivity"

	return $?

}



check_traceroute()

{

	if [ ! -x "$(command -v traceroute)" ]; then

		echo "SKIP: Could not run IPV4 test without traceroute"

		return 1

	fi

}



check_traceroute6()

{

	if [ ! -x "$(command -v traceroute6)" ]; then

		echo "SKIP: Could not run IPV6 test without traceroute6"

		return 1

	fi

}



ipv4_traceroute()

{

	local ttype="$1"



	[ "x$ttype" = "x" ] && ttype="$DEFAULT_TTYPE"



	log_section "IPv4 ($ttype route): VRF ICMP error route lookup traceroute"



	check_traceroute || return



	setup_"$ttype"



	check_connectivity || return



	run_cmd_grep "${R1_N1_IP}" ip netns exec h1 traceroute ${H2_N2_IP}

	log_test $? 0 "Traceroute reports a hop on r1"

}



ipv4_traceroute_asym()

{

	ipv4_traceroute asym

}



ipv6_traceroute()

{

	local ttype="$1"



	[ "x$ttype" = "x" ] && ttype="$DEFAULT_TTYPE"



	log_section "IPv6 ($ttype route): VRF ICMP error route lookup traceroute"



	check_traceroute6 || return



	setup_"$ttype"



	check_connectivity6 || return



	run_cmd_grep "${R1_N1_IP6}" ip netns exec h1 traceroute6 ${H2_N2_IP6}

	log_test $? 0 "Traceroute6 reports a hop on r1"

}



ipv6_traceroute_asym()

{

	ipv6_traceroute asym

}



ipv4_ping_ttl()

{

	local ttype="$1"



	[ "x$ttype" = "x" ] && ttype="$DEFAULT_TTYPE"



	log_section "IPv4 ($ttype route): VRF ICMP ttl error route lookup ping"



	setup_"$ttype"



	check_connectivity || return



	run_cmd_grep "Time to live exceeded" ip netns exec h1 ping -t1 -c1 -W2 ${H2_N2_IP}

	log_test $? 0 "Ping received ICMP ttl exceeded"

}



ipv4_ping_ttl_asym()

{

	ipv4_ping_ttl asym

}



ipv4_ping_frag()

{

	local ttype="$1"



	[ "x$ttype" = "x" ] && ttype="$DEFAULT_TTYPE"



	log_section "IPv4 ($ttype route): VRF ICMP fragmentation error route lookup ping"



	setup_"$ttype"



	check_connectivity || return



	run_cmd_grep "Frag needed" ip netns exec h1 ping -s 1450 -Mdo -c1 -W2 ${H2_N2_IP}

	log_test $? 0 "Ping received ICMP Frag needed"

}



ipv4_ping_frag_asym()

{

	ipv4_ping_frag asym

}



ipv6_ping_ttl()

{

	local ttype="$1"



	[ "x$ttype" = "x" ] && ttype="$DEFAULT_TTYPE"



	log_section "IPv6 ($ttype route): VRF ICMP ttl error route lookup ping"



	setup_"$ttype"



	check_connectivity6 || return



	run_cmd_grep "Time exceeded: Hop limit" ip netns exec h1 "${ping6}" -t1 -c1 -W2 ${H2_N2_IP6}

	log_test $? 0 "Ping received ICMP Hop limit"

}



ipv6_ping_ttl_asym()

{

	ipv6_ping_ttl asym

}



ipv6_ping_frag()

{

	local ttype="$1"



	[ "x$ttype" = "x" ] && ttype="$DEFAULT_TTYPE"



	log_section "IPv6 ($ttype route): VRF ICMP fragmentation error route lookup ping"



	setup_"$ttype"



	check_connectivity6 || return



	run_cmd_grep "Packet too big" ip netns exec h1 "${ping6}" -s 1450 -Mdo -c1 -W2 ${H2_N2_IP6}

	log_test $? 0 "Ping received ICMP Packet too big"

}



ipv6_ping_frag_asym()

{

	ipv6_ping_frag asym

}



################################################################################

# usage



usage()

{

        cat <<EOF

usage: ${0##*/} OPTS



	-4          Run IPv4 tests only

	-6          Run IPv6 tests only

        -t TEST     Run only TEST

	-p          Pause on fail

	-v          verbose mode (show commands and output)

EOF

}



################################################################################

# main



# Some systems don't have a ping6 binary anymore

command -v ping6 > /dev/null 2>&1 && ping6=$(command -v ping6) || ping6=$(command -v ping)



TESTS_IPV4="ipv4_ping_ttl ipv4_traceroute ipv4_ping_frag ipv4_ping_ttl_asym ipv4_traceroute_asym"

TESTS_IPV6="ipv6_ping_ttl ipv6_traceroute ipv6_ping_frag ipv6_ping_ttl_asym ipv6_traceroute_asym"



ret=0

nsuccess=0

nfail=0



while getopts :46t:pvh o

do

	case $o in

		4) TESTS=ipv4;;

		6) TESTS=ipv6;;

		t) TESTS=$OPTARG;;

		p) PAUSE_ON_FAIL=yes;;

		v) VERBOSE=1;;

		h) usage; exit 0;;

		*) usage; exit 1;;

	esac

done



#

# show user test config

#

if [ -z "$TESTS" ]; then

        TESTS="$TESTS_IPV4 $TESTS_IPV6"

elif [ "$TESTS" = "ipv4" ]; then

        TESTS="$TESTS_IPV4"

elif [ "$TESTS" = "ipv6" ]; then

        TESTS="$TESTS_IPV6"

fi



for t in $TESTS

do

	case $t in

	ipv4_ping_ttl|ping)              ipv4_ping_ttl;;&

	ipv4_ping_ttl_asym|ping)         ipv4_ping_ttl_asym;;&

	ipv4_traceroute|traceroute)      ipv4_traceroute;;&

	ipv4_traceroute_asym|traceroute) ipv4_traceroute_asym;;&

	ipv4_ping_frag|ping)             ipv4_ping_frag;;&



	ipv6_ping_ttl|ping)              ipv6_ping_ttl;;&

	ipv6_ping_ttl_asym|ping)         ipv6_ping_ttl_asym;;&

	ipv6_traceroute|traceroute)      ipv6_traceroute;;&

	ipv6_traceroute_asym|traceroute) ipv6_traceroute_asym;;&

	ipv6_ping_frag|ping)             ipv6_ping_frag;;&



	# setup namespaces and config, but do not run any tests

	setup_sym|setup)                 setup_sym; exit 0;;

	setup_asym)                      setup_asym; exit 0;;



	help)                       echo "Test names: $TESTS"; exit 0;;

	esac

done



cleanup



printf "\nTests passed: %3d\n" ${nsuccess}

printf "Tests failed: %3d\n"   ${nfail}



exit $ret

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