selftests: Add VRF route leaking tests

The objective of the tests is to check that ICMP errors generated while
crossing between VRFs are properly routed back to the source host.

The first ttl 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 ttl test runs traceroute from h1 to h2 and parses the output to
check for a hop on r1.

The mtu test sends a ping with a payload of 1450 from h1 to h2, through
r1 which has an interface with a mtu of 1400 and parses the output of the
command to check that a fragmentation needed error is received.

[ The IPv6 MTU test still fails with the symmetric routing setup. It
  appears to be caused by source address selection picking ::1.  Fixing
  this is beyond the scope of this series. ]

Signed-off-by: Michael Jeanson <mjeanson@efficios.com>
Reviewed-by: David Ahern <dsahern@gmail.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

2 files changed, 627 insertions, 0 deletions

diff --git a/tools/testing/selftests/net/Makefile b/tools/testing/selftests/net/Makefile
index 9491bbaa0831..3e7fb1e70c77 100644
--- a/tools/testing/selftests/net/Makefile
+++ b/tools/testing/selftests/net/Makefile
@@ -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
diff --git a/tools/testing/selftests/net/vrf_route_leaking.sh b/tools/testing/selftests/net/vrf_route_leaking.sh
new file mode 100755
index 000000000000..23cf924754a5
--- /dev/null
+++ b/tools/testing/selftests/net/vrf_route_leaking.sh
@@ -0,0 +1,626 @@
+#!/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