Re: [PATCH net-next v9] net: ipv4: Cache pmtu for all packet paths if multipath enabled

[Ido Schimmel <idosch@idosch.org>]

On Thu, Nov 07, 2024 at 09:36:24AM +0000, Vladimir Vdovin wrote:
> +test_pmtu_ipv4_mp_exceptions() {
> +	setup namespaces routing multipath || return $ksft_skip
> +
> +	trace "${ns_a}"  veth_A-R1    "${ns_r1}" veth_R1-A \
> +	      "${ns_r1}" veth_R1-B    "${ns_b}"  veth_B-R1 \
> +	      "${ns_a}"  veth_A-R2    "${ns_r2}" veth_R2-A \
> +	      "${ns_r2}" veth_R2-B    "${ns_b}"  veth_B-R2
> +
> +	# Set up initial MTU values
> +	mtu "${ns_a}"  veth_A-R1 2000
> +	mtu "${ns_r1}" veth_R1-A 2000
> +	mtu "${ns_r1}" veth_R1-B 1500
> +	mtu "${ns_b}"  veth_B-R1 1500
> +
> +	mtu "${ns_a}"  veth_A-R2 2000
> +	mtu "${ns_r2}" veth_R2-A 2000
> +	mtu "${ns_r2}" veth_R2-B 1500
> +	mtu "${ns_b}"  veth_B-R2 1500
> +
> +	fail=0
> +
> +	# Ping and expect two nexthop exceptions for two routes in nh group
> +	run_cmd ${ns_a} ping -q -M want -i 0.1 -c 1 -s 1800 "${host4_b_addr}"
> +
> +	# Do route lookup before checking cached exceptions.
> +	# The following commands are needed for dst entries to be cached
> +	# in both paths exceptions and therefore dumped to user space
> +	# Check that exceptions have been created with the correct PMTU
> +	pmtu_a_R1="$(route_get_dst_pmtu_from_exception "${ns_a}" "${host4_b_addr}" oif veth_A-R1)"
> +	pmtu_a_R2="$(route_get_dst_pmtu_from_exception "${ns_a}" "${host4_b_addr}" oif veth_A-R2)"
> +

In addition to the removal of 'fail=0' that you already mentioned, also
need to flip the error messages:

> +	check_pmtu_value "1500" "${pmtu_a_R1}" "exceeding MTU (veth_A-R2)" || return 1

s/veth_A-R2/veth_A-R1/

> +	check_pmtu_value "1500" "${pmtu_a_R2}" "exceeding MTU (veth_A-R1)" || return 1

s/veth_A-R1/veth_A-R2/

> +}
> +
>  usage() {
>  	echo
>  	echo "$0 [OPTIONS] [TEST]..."
> 
> base-commit: 66600fac7a984dea4ae095411f644770b2561ede
> -- 
> 2.43.5
>