selftests: net: Introduce first PMTU test

CFLAGS += -I../../../../usr/include/

TEST_PROGS := run_netsocktests run_afpackettests test_bpf.sh netdevice.sh rtnetlink.sh

TEST_PROGS += fib_tests.sh fib-onlink-tests.sh

TEST_PROGS += fib_tests.sh fib-onlink-tests.sh pmtu.sh

TEST_GEN_FILES =  socket

TEST_GEN_FILES += psock_fanout psock_tpacket msg_zerocopy

TEST_GEN_PROGS = reuseport_bpf reuseport_bpf_cpu reuseport_bpf_numa

#!/bin/sh

# SPDX-License-Identifier: GPL-2.0

#

# Check that route PMTU values match expectations

#

# Tests currently implemented:

#

# - test_pmtu_vti6_exception

#	Set up vti6 tunnel on top of veth, with xfrm states and policies, in two

#	namespaces with matching endpoints. Check that route exception is

#	created by exceeding link layer MTU with ping to other endpoint. Then

#	decrease and increase MTU of tunnel, checking that route exception PMTU

#	changes accordingly

NS_A="ns-$(mktemp -u XXXXXX)"

NS_B="ns-$(mktemp -u XXXXXX)"

ns_a="ip netns exec ${NS_A}"

ns_b="ip netns exec ${NS_B}"

veth6_a_addr="fd00:1::a"

veth6_b_addr="fd00:1::b"

veth6_mask="64"

vti6_a_addr="fd00:2::a"

vti6_b_addr="fd00:2::b"

vti6_mask="64"

setup_namespaces() {

	ip netns add ${NS_A} || return 0

	ip netns add ${NS_B}

	return 1

}

setup_veth() {

	${ns_a} ip link add veth_a type veth peer name veth_b || return 0

	${ns_a} ip link set veth_b netns ${NS_B}

	${ns_a} ip addr add ${veth6_a_addr}/${veth6_mask} dev veth_a

	${ns_b} ip addr add ${veth6_b_addr}/${veth6_mask} dev veth_b

	${ns_a} ip link set veth_a up

	${ns_b} ip link set veth_b up

	return 1

}

setup_vti6() {

	${ns_a} ip link add vti_a type vti6 local ${veth6_a_addr} remote ${veth6_b_addr} key 10 || return 0

	${ns_b} ip link add vti_b type vti6 local ${veth6_b_addr} remote ${veth6_a_addr} key 10

	${ns_a} ip addr add ${vti6_a_addr}/${vti6_mask} dev vti_a

	${ns_b} ip addr add ${vti6_b_addr}/${vti6_mask} dev vti_b

	${ns_a} ip link set vti_a up

	${ns_b} ip link set vti_b up

	sleep 1

	return 1

}

setup_xfrm() {

	${ns_a} ip -6 xfrm state add src ${veth6_a_addr} dst ${veth6_b_addr} spi 0x1000 proto esp aead "rfc4106(gcm(aes))" 0x0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f 128 mode tunnel || return 0

	${ns_a} ip -6 xfrm state add src ${veth6_b_addr} dst ${veth6_a_addr} spi 0x1001 proto esp aead "rfc4106(gcm(aes))" 0x0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f 128 mode tunnel

	${ns_a} ip -6 xfrm policy add dir out mark 10 tmpl src ${veth6_a_addr} dst ${veth6_b_addr} proto esp mode tunnel

	${ns_a} ip -6 xfrm policy add dir in mark 10 tmpl src ${veth6_b_addr} dst ${veth6_a_addr} proto esp mode tunnel

	${ns_b} ip -6 xfrm state add src ${veth6_a_addr} dst ${veth6_b_addr} spi 0x1000 proto esp aead "rfc4106(gcm(aes))" 0x0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f 128 mode tunnel

	${ns_b} ip -6 xfrm state add src ${veth6_b_addr} dst ${veth6_a_addr} spi 0x1001 proto esp aead "rfc4106(gcm(aes))" 0x0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f 128 mode tunnel

	${ns_b} ip -6 xfrm policy add dir out mark 10 tmpl src ${veth6_b_addr} dst ${veth6_a_addr} proto esp mode tunnel

	${ns_b} ip -6 xfrm policy add dir in mark 10 tmpl src ${veth6_a_addr} dst ${veth6_b_addr} proto esp mode tunnel

	return 1

}

setup() {

	tunnel_type="$1"

	[ "$(id -u)" -ne 0 ] && echo "SKIP: need to run as root" && exit 0

	setup_namespaces && echo "SKIP: namespaces not supported" && exit 0

	setup_veth && echo "SKIP: veth not supported" && exit 0

	case ${tunnel_type} in

	"vti6")

		setup_vti6 && echo "SKIP: vti6 not supported" && exit 0

		setup_xfrm && echo "SKIP: xfrm not supported" && exit 0

		;;

	*)

		;;

	esac

}

cleanup() {

	ip netns del ${NS_A} 2 > /dev/null

	ip netns del ${NS_B} 2 > /dev/null

}

mtu() {

	ns_cmd="${1}"

	dev="${2}"

	mtu="${3}"

	${ns_cmd} ip link set dev ${dev} mtu ${mtu}

}

route_get_dst_exception() {

	dst="${1}"

	${ns_a} ip route get "${dst}"

}

route_get_dst_pmtu_from_exception() {

	dst="${1}"

	exception="$(route_get_dst_exception ${dst})"

	next=0

	for i in ${exception}; do

		[ ${next} -eq 1 ] && echo "${i}" && return

		[ "${i}" = "mtu" ] && next=1

	done

}

test_pmtu_vti6_exception() {

	setup vti6

	# Create route exception by exceeding link layer MTU

	mtu "${ns_a}" veth_a 4000

	mtu "${ns_b}" veth_b 4000

	mtu "${ns_a}" vti_a 5000

	mtu "${ns_b}" vti_b 5000

	${ns_a} ping6 -q -i 0.1 -w 2 -s 60000 ${vti6_b_addr} > /dev/null

	# Check that exception was created

	if [ "$(route_get_dst_pmtu_from_exception ${vti6_b_addr})" = "" ]; then

		echo "FAIL: Tunnel exceeding link layer MTU didn't create route exception"

		exit 1

	fi

	# Decrease tunnel MTU, check for PMTU decrease in route exception

	mtu "${ns_a}" vti_a 3000

	if [ "$(route_get_dst_pmtu_from_exception ${vti6_b_addr})" -ne 3000 ]; then

		echo "FAIL: Decreasing tunnel MTU didn't decrease route exception PMTU"

		exit 1

	fi

	# Increase tunnel MTU, check for PMTU increase in route exception

	mtu "${ns_a}" vti_a 9000

	if [ "$(route_get_dst_pmtu_from_exception ${vti6_b_addr})" -ne 9000 ]; then

		echo "FAIL: Increasing tunnel MTU didn't increase route exception PMTU"

		exit 1

	fi

	echo "PASS"

}

trap cleanup EXIT

test_pmtu_vti6_exception

exit 0