#!/bin/bash
# SPDX-License-Identifier: GPL-2.0

# Test for DSCP prioritization in the router.
#
# With ip_forward_update_priority disabled, the packets are expected to keep
# their DSCP (which in this test uses only values 0..7) intact as they are
# forwarded by the switch. That is verified at $h2. ICMP responses are formed
# with the same DSCP as the requests, and likewise pass through the switch
# intact, which is verified at $h1.
#
# With ip_forward_update_priority enabled, router reprioritizes the packets
# according to the table in reprioritize(). Thus, say, DSCP 7 maps to priority
# 4, which on egress maps back to DSCP 4. The response packet then gets
# reprioritized to 6, getting DSCP 6 on egress.
#
# +----------------------+                             +----------------------+
# | H1                   |                             |                   H2 |
# |    + $h1             |                             |            $h2 +     |
# |    | 192.0.2.1/28    |                             |  192.0.2.18/28 |     |
# +----|-----------------+                             +----------------|-----+
#      |                                                                |
# +----|----------------------------------------------------------------|-----+
# | SW |                                                                |     |
# |    + $swp1                                                    $swp2 +     |
# |      192.0.2.2/28                                     192.0.2.17/28       |
# |      APP=0,5,0 .. 7,5,7                          APP=0,5,0 .. 7,5,7       |
# +---------------------------------------------------------------------------+

ALL_TESTS="
	ping_ipv4
	test_update
	test_no_update
"

lib_dir=$(dirname $0)/../../../net/forwarding

NUM_NETIFS=4
source $lib_dir/lib.sh

reprioritize()
{
	local in=$1; shift

	# This is based on rt_tos2priority in include/net/route.h. Assuming 1:1
	# mapping between priorities and TOS, it yields a new priority for a
	# packet with ingress priority of $in.
	local -a reprio=(0 0 2 2 6 6 4 4)

	echo ${reprio[$in]}
}

h1_create()
{
	local dscp;

	simple_if_init $h1 192.0.2.1/28
	tc qdisc add dev $h1 clsact
	dscp_capture_install $h1 0
	ip route add vrf v$h1 192.0.2.16/28 via 192.0.2.2
}

h1_destroy()
{
	ip route del vrf v$h1 192.0.2.16/28 via 192.0.2.2
	dscp_capture_uninstall $h1 0
	tc qdisc del dev $h1 clsact
	simple_if_fini $h1 192.0.2.1/28
}

h2_create()
{
	simple_if_init $h2 192.0.2.18/28
	tc qdisc add dev $h2 clsact
	dscp_capture_install $h2 0
	ip route add vrf v$h2 192.0.2.0/28 via 192.0.2.17
}

h2_destroy()
{
	ip route del vrf v$h2 192.0.2.0/28 via 192.0.2.17
	dscp_capture_uninstall $h2 0
	tc qdisc del dev $h2 clsact
	simple_if_fini $h2 192.0.2.18/28
}

dscp_map()
{
	local base=$1; shift

	for prio in {0..7}; do
		echo app=$prio,5,$((base + prio))
	done
}

switch_create()
{
	simple_if_init $swp1 192.0.2.2/28
	__simple_if_init $swp2 v$swp1 192.0.2.17/28

	lldptool -T -i $swp1 -V APP $(dscp_map 0) >/dev/null
	lldptool -T -i $swp2 -V APP $(dscp_map 0) >/dev/null
	lldpad_app_wait_set $swp1
	lldpad_app_wait_set $swp2
}

switch_destroy()
{
	lldptool -T -i $swp2 -V APP -d $(dscp_map 0) >/dev/null
	lldptool -T -i $swp1 -V APP -d $(dscp_map 0) >/dev/null
	lldpad_app_wait_del

	__simple_if_fini $swp2 192.0.2.17/28
	simple_if_fini $swp1 192.0.2.2/28
}

setup_prepare()
{
	h1=${NETIFS[p1]}
	swp1=${NETIFS[p2]}

	swp2=${NETIFS[p3]}
	h2=${NETIFS[p4]}

	vrf_prepare

	sysctl_set net.ipv4.ip_forward_update_priority 1
	h1_create
	h2_create
	switch_create
}

cleanup()
{
	pre_cleanup

	switch_destroy
	h2_destroy
	h1_destroy
	sysctl_restore net.ipv4.ip_forward_update_priority

	vrf_cleanup
}

ping_ipv4()
{
	ping_test $h1 192.0.2.18
}

dscp_ping_test()
{
	local vrf_name=$1; shift
	local sip=$1; shift
	local dip=$1; shift
	local prio=$1; shift
	local reprio=$1; shift
	local dev1=$1; shift
	local dev2=$1; shift

	local prio2=$($reprio $prio)   # ICMP Request egress prio
	local prio3=$($reprio $prio2)  # ICMP Response egress prio

	local dscp=$((prio << 2))     # ICMP Request ingress DSCP
	local dscp2=$((prio2 << 2))   # ICMP Request egress DSCP
	local dscp3=$((prio3 << 2))   # ICMP Response egress DSCP

	RET=0

	eval "local -A dev1_t0s=($(dscp_fetch_stats $dev1 0))"
	eval "local -A dev2_t0s=($(dscp_fetch_stats $dev2 0))"

	ip vrf exec $vrf_name \
	   ${PING} -Q $dscp ${sip:+-I $sip} $dip \
		   -c 10 -i 0.1 -w 2 &> /dev/null

	eval "local -A dev1_t1s=($(dscp_fetch_stats $dev1 0))"
	eval "local -A dev2_t1s=($(dscp_fetch_stats $dev2 0))"

	for i in {0..7}; do
		local dscpi=$((i << 2))
		local expect2=0
		local expect3=0

		if ((i == prio2)); then
			expect2=10
		fi
		if ((i == prio3)); then
			expect3=10
		fi

		local delta=$((dev2_t1s[$i] - dev2_t0s[$i]))
		((expect2 == delta))
		check_err $? "DSCP $dscpi@$dev2: Expected to capture $expect2 packets, got $delta."

		delta=$((dev1_t1s[$i] - dev1_t0s[$i]))
		((expect3 == delta))
		check_err $? "DSCP $dscpi@$dev1: Expected to capture $expect3 packets, got $delta."
	done

	log_test "DSCP rewrite: $dscp-(prio $prio2)-$dscp2-(prio $prio3)-$dscp3"
}

__test_update()
{
	local update=$1; shift
	local reprio=$1; shift

	sysctl_restore net.ipv4.ip_forward_update_priority
	sysctl_set net.ipv4.ip_forward_update_priority $update

	for prio in {0..7}; do
		dscp_ping_test v$h1 192.0.2.1 192.0.2.18 $prio $reprio $h1 $h2
	done
}

test_update()
{
	__test_update 1 reprioritize
}

test_no_update()
{
	__test_update 0 echo
}

trap cleanup EXIT

setup_prepare
setup_wait

tests_run

exit $EXIT_STATUS