1

selftests/net: test l2 tunnel TOS/TTL inheriting

There are currently 3 ip tunnels that are capable of carrying
L2 traffic: gretap, vxlan and geneve.
They all are capable to inherit the TOS/TTL for the outer
IP-header from the inner frame.

Add a test that verifies that these fields are correctly inherited.

These tests failed before the following commits:
b09ab9c92e ("ip6_tunnel: allow to inherit from VLAN encapsulated IP")
3f8a8447fd ("ip6_gre: use actual protocol to select xmit")
41337f52b9 ("ip6_gre: set DSCP for non-IP")
7ae29fd1be ("ip_tunnel: allow to inherit from VLAN encapsulated IP")
7074732c8f ("ip_tunnels: allow VXLAN/GENEVE to inherit TOS/TTL from VLAN")
ca2bb69514 ("geneve: do not use RT_TOS for IPv6 flowlabel")
b4ab94d6ad ("geneve: fix TOS inheriting for ipv4")

Signed-off-by: Matthias May <matthias.may@westermo.com>
Link: https://lore.kernel.org/r/20220817073649.26117-1-matthias.may@westermo.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Matthias May 2022-08-17 09:36:49 +02:00 committed by Jakub Kicinski
parent 14d25e3f53
commit b690842d12
2 changed files with 391 additions and 0 deletions

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@ -42,6 +42,7 @@ TEST_PROGS += arp_ndisc_evict_nocarrier.sh
TEST_PROGS += ndisc_unsolicited_na_test.sh
TEST_PROGS += arp_ndisc_untracked_subnets.sh
TEST_PROGS += stress_reuseport_listen.sh
TEST_PROGS := l2_tos_ttl_inherit.sh
TEST_PROGS_EXTENDED := in_netns.sh setup_loopback.sh setup_veth.sh
TEST_PROGS_EXTENDED += toeplitz_client.sh toeplitz.sh
TEST_GEN_FILES = socket nettest

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@ -0,0 +1,390 @@
#!/bin/sh
# SPDX-License-Identifier: GPL-2.0
# Author: Matthias May <matthias.may@westermo.com>
#
# This script evaluates ip tunnels that are capable of carrying L2 traffic
# if they inherit or set the inheritable fields.
# Namely these tunnels are: 'gretap', 'vxlan' and 'geneve'.
# Checked inheritable fields are: TOS and TTL.
# The outer tunnel protocol of 'IPv4' or 'IPv6' is verified-
# As payload frames of type 'IPv4', 'IPv6' and 'other'(ARP) are verified.
# In addition this script also checks if forcing a specific field in the
# outer header is working.
if [ "$(id -u)" != "0" ]; then
echo "Please run as root."
exit 0
fi
if ! which tcpdump > /dev/null 2>&1; then
echo "No tcpdump found. Required for this test."
exit 0
fi
expected_tos="0x00"
expected_ttl="0"
failed=false
get_random_tos() {
# Get a random hex tos value between 0x00 and 0xfc, a multiple of 4
echo "0x$(tr -dc '0-9a-f' < /dev/urandom | head -c 1)\
$(tr -dc '048c' < /dev/urandom | head -c 1)"
}
get_random_ttl() {
# Get a random dec value between 0 and 255
printf "%d" "0x$(tr -dc '0-9a-f' < /dev/urandom | head -c 2)"
}
get_field() {
# Expects to get the 'head -n 1' of a captured frame by tcpdump.
# Parses this first line and returns the specified field.
local field="$1"
local input="$2"
local found=false
input="$(echo "$input" | tr -d '(),')"
for input_field in $input; do
if $found; then
echo "$input_field"
return
fi
# The next field that we iterate over is the looked for value
if [ "$input_field" = "$field" ]; then
found=true
fi
done
echo "0"
}
setup() {
local type="$1"
local outer="$2"
local inner="$3"
local tos_ttl="$4"
local vlan="$5"
local test_tos="0x00"
local test_ttl="0"
local ns="ip netns exec testing"
# We don't want a test-tos of 0x00,
# because this is the value that we get when no tos is set.
expected_tos="$(get_random_tos)"
while [ "$expected_tos" = "0x00" ]; do
expected_tos="$(get_random_tos)"
done
if [ "$tos_ttl" = "random" ]; then
test_tos="$expected_tos"
tos="fixed $test_tos"
elif [ "$tos_ttl" = "inherit" ]; then
test_tos="$tos_ttl"
tos="inherit $expected_tos"
fi
# We don't want a test-ttl of 64 or 0,
# because 64 is when no ttl is set and 0 is not a valid ttl.
expected_ttl="$(get_random_ttl)"
while [ "$expected_ttl" = "64" ] || [ "$expected_ttl" = "0" ]; do
expected_ttl="$(get_random_ttl)"
done
if [ "$tos_ttl" = "random" ]; then
test_ttl="$expected_ttl"
ttl="fixed $test_ttl"
elif [ "$tos_ttl" = "inherit" ]; then
test_ttl="$tos_ttl"
ttl="inherit $expected_ttl"
fi
printf "│%7s │%6s │%6s │%13s │%13s │%6s │" \
"$type" "$outer" "$inner" "$tos" "$ttl" "$vlan"
# Create 'testing' netns, veth pair and connect main ns with testing ns
ip netns add testing
ip link add type veth
ip link set veth1 netns testing
ip link set veth0 up
$ns ip link set veth1 up
ip addr flush dev veth0
$ns ip addr flush dev veth1
local local_addr1=""
local local_addr2=""
if [ "$type" = "gre" ] || [ "$type" = "vxlan" ]; then
if [ "$outer" = "4" ]; then
local_addr1="local 198.18.0.1"
local_addr2="local 198.18.0.2"
elif [ "$outer" = "6" ]; then
local_addr1="local fdd1:ced0:5d88:3fce::1"
local_addr2="local fdd1:ced0:5d88:3fce::2"
fi
fi
local vxlan=""
if [ "$type" = "vxlan" ]; then
vxlan="vni 100 dstport 4789"
fi
local geneve=""
if [ "$type" = "geneve" ]; then
geneve="vni 100"
fi
# Create tunnel and assign outer IPv4/IPv6 addresses
if [ "$outer" = "4" ]; then
if [ "$type" = "gre" ]; then
type="gretap"
fi
ip addr add 198.18.0.1/24 dev veth0
$ns ip addr add 198.18.0.2/24 dev veth1
ip link add name tep0 type $type $local_addr1 remote \
198.18.0.2 tos $test_tos ttl $test_ttl $vxlan $geneve
$ns ip link add name tep1 type $type $local_addr2 remote \
198.18.0.1 tos $test_tos ttl $test_ttl $vxlan $geneve
elif [ "$outer" = "6" ]; then
if [ "$type" = "gre" ]; then
type="ip6gretap"
fi
ip addr add fdd1:ced0:5d88:3fce::1/64 dev veth0
$ns ip addr add fdd1:ced0:5d88:3fce::2/64 dev veth1
ip link add name tep0 type $type $local_addr1 \
remote fdd1:ced0:5d88:3fce::2 tos $test_tos ttl $test_ttl \
$vxlan $geneve
$ns ip link add name tep1 type $type $local_addr2 \
remote fdd1:ced0:5d88:3fce::1 tos $test_tos ttl $test_ttl \
$vxlan $geneve
fi
# Bring L2-tunnel link up and create VLAN on top
ip link set tep0 up
$ns ip link set tep1 up
ip addr flush dev tep0
$ns ip addr flush dev tep1
local parent
if $vlan; then
parent="vlan99-"
ip link add link tep0 name ${parent}0 type vlan id 99
$ns ip link add link tep1 name ${parent}1 type vlan id 99
ip link set ${parent}0 up
$ns ip link set ${parent}1 up
ip addr flush dev ${parent}0
$ns ip addr flush dev ${parent}1
else
parent="tep"
fi
# Assign inner IPv4/IPv6 addresses
if [ "$inner" = "4" ] || [ "$inner" = "other" ]; then
ip addr add 198.19.0.1/24 brd + dev ${parent}0
$ns ip addr add 198.19.0.2/24 brd + dev ${parent}1
elif [ "$inner" = "6" ]; then
ip addr add fdd4:96cf:4eae:443b::1/64 dev ${parent}0
$ns ip addr add fdd4:96cf:4eae:443b::2/64 dev ${parent}1
fi
}
verify() {
local outer="$1"
local inner="$2"
local tos_ttl="$3"
local vlan="$4"
local ping_pid out captured_tos captured_ttl result
local ping_dst
if [ "$inner" = "4" ]; then
ping_dst="198.19.0.2"
elif [ "$inner" = "6" ]; then
ping_dst="fdd4:96cf:4eae:443b::2"
elif [ "$inner" = "other" ]; then
ping_dst="198.19.0.3" # Generates ARPs which are not IPv4/IPv6
fi
if [ "$tos_ttl" = "inherit" ]; then
ping -i 0.1 $ping_dst -Q "$expected_tos" -t "$expected_ttl" \
2>/dev/null 1>&2 & ping_pid="$!"
else
ping -i 0.1 $ping_dst 2>/dev/null 1>&2 & ping_pid="$!"
fi
local tunnel_type_offset tunnel_type_proto req_proto_offset req_offset
if [ "$type" = "gre" ]; then
tunnel_type_proto="0x2f"
elif [ "$type" = "vxlan" ] || [ "$type" = "geneve" ]; then
tunnel_type_proto="0x11"
fi
if [ "$outer" = "4" ]; then
tunnel_type_offset="9"
if [ "$inner" = "4" ]; then
req_proto_offset="47"
req_offset="58"
if [ "$type" = "vxlan" ] || [ "$type" = "geneve" ]; then
req_proto_offset="$((req_proto_offset + 12))"
req_offset="$((req_offset + 12))"
fi
if $vlan; then
req_proto_offset="$((req_proto_offset + 4))"
req_offset="$((req_offset + 4))"
fi
out="$(tcpdump --immediate-mode -p -c 1 -v -i veth0 -n \
ip[$tunnel_type_offset] = $tunnel_type_proto and \
ip[$req_proto_offset] = 0x01 and \
ip[$req_offset] = 0x08 2>/dev/null | head -n 1)"
elif [ "$inner" = "6" ]; then
req_proto_offset="44"
req_offset="78"
if [ "$type" = "vxlan" ] || [ "$type" = "geneve" ]; then
req_proto_offset="$((req_proto_offset + 12))"
req_offset="$((req_offset + 12))"
fi
if $vlan; then
req_proto_offset="$((req_proto_offset + 4))"
req_offset="$((req_offset + 4))"
fi
out="$(tcpdump --immediate-mode -p -c 1 -v -i veth0 -n \
ip[$tunnel_type_offset] = $tunnel_type_proto and \
ip[$req_proto_offset] = 0x3a and \
ip[$req_offset] = 0x80 2>/dev/null | head -n 1)"
elif [ "$inner" = "other" ]; then
req_proto_offset="36"
req_offset="45"
if [ "$type" = "vxlan" ] || [ "$type" = "geneve" ]; then
req_proto_offset="$((req_proto_offset + 12))"
req_offset="$((req_offset + 12))"
fi
if $vlan; then
req_proto_offset="$((req_proto_offset + 4))"
req_offset="$((req_offset + 4))"
fi
if [ "$tos_ttl" = "inherit" ]; then
expected_tos="0x00"
expected_ttl="64"
fi
out="$(tcpdump --immediate-mode -p -c 1 -v -i veth0 -n \
ip[$tunnel_type_offset] = $tunnel_type_proto and \
ip[$req_proto_offset] = 0x08 and \
ip[$((req_proto_offset + 1))] = 0x06 and \
ip[$req_offset] = 0x01 2>/dev/null | head -n 1)"
fi
elif [ "$outer" = "6" ]; then
if [ "$type" = "gre" ]; then
tunnel_type_offset="40"
elif [ "$type" = "vxlan" ] || [ "$type" = "geneve" ]; then
tunnel_type_offset="6"
fi
if [ "$inner" = "4" ]; then
local req_proto_offset="75"
local req_offset="86"
if [ "$type" = "vxlan" ] || [ "$type" = "geneve" ]; then
req_proto_offset="$((req_proto_offset + 4))"
req_offset="$((req_offset + 4))"
fi
if $vlan; then
req_proto_offset="$((req_proto_offset + 4))"
req_offset="$((req_offset + 4))"
fi
out="$(tcpdump --immediate-mode -p -c 1 -v -i veth0 -n \
ip6[$tunnel_type_offset] = $tunnel_type_proto and \
ip6[$req_proto_offset] = 0x01 and \
ip6[$req_offset] = 0x08 2>/dev/null | head -n 1)"
elif [ "$inner" = "6" ]; then
local req_proto_offset="72"
local req_offset="106"
if [ "$type" = "vxlan" ] || [ "$type" = "geneve" ]; then
req_proto_offset="$((req_proto_offset + 4))"
req_offset="$((req_offset + 4))"
fi
if $vlan; then
req_proto_offset="$((req_proto_offset + 4))"
req_offset="$((req_offset + 4))"
fi
out="$(tcpdump --immediate-mode -p -c 1 -v -i veth0 -n \
ip6[$tunnel_type_offset] = $tunnel_type_proto and \
ip6[$req_proto_offset] = 0x3a and \
ip6[$req_offset] = 0x80 2>/dev/null | head -n 1)"
elif [ "$inner" = "other" ]; then
local req_proto_offset="64"
local req_offset="73"
if [ "$type" = "vxlan" ] || [ "$type" = "geneve" ]; then
req_proto_offset="$((req_proto_offset + 4))"
req_offset="$((req_offset + 4))"
fi
if $vlan; then
req_proto_offset="$((req_proto_offset + 4))"
req_offset="$((req_offset + 4))"
fi
if [ "$tos_ttl" = "inherit" ]; then
expected_tos="0x00"
expected_ttl="64"
fi
out="$(tcpdump --immediate-mode -p -c 1 -v -i veth0 -n \
ip6[$tunnel_type_offset] = $tunnel_type_proto and \
ip6[$req_proto_offset] = 0x08 and \
ip6[$((req_proto_offset + 1))] = 0x06 and \
ip6[$req_offset] = 0x01 2>/dev/null | head -n 1)"
fi
fi
kill -9 $ping_pid
wait $ping_pid 2>/dev/null
result="FAIL"
if [ "$outer" = "4" ]; then
captured_ttl="$(get_field "ttl" "$out")"
captured_tos="$(printf "0x%02x" "$(get_field "tos" "$out")")"
if [ "$captured_tos" = "$expected_tos" ] &&
[ "$captured_ttl" = "$expected_ttl" ]; then
result="OK"
fi
elif [ "$outer" = "6" ]; then
captured_ttl="$(get_field "hlim" "$out")"
captured_tos="$(printf "0x%02x" "$(get_field "class" "$out")")"
if [ "$captured_tos" = "$expected_tos" ] &&
[ "$captured_ttl" = "$expected_ttl" ]; then
result="OK"
fi
fi
printf "%7s │\n" "$result"
if [ "$result" = "FAIL" ]; then
failed=true
if [ "$captured_tos" != "$expected_tos" ]; then
printf "│%43s%27s │\n" \
"Expected TOS value: $expected_tos" \
"Captured TOS value: $captured_tos"
fi
if [ "$captured_ttl" != "$expected_ttl" ]; then
printf "│%43s%27s │\n" \
"Expected TTL value: $expected_ttl" \
"Captured TTL value: $captured_ttl"
fi
printf "│%71s│\n" " "
fi
}
cleanup() {
ip link del veth0 2>/dev/null
ip netns del testing 2>/dev/null
ip link del tep0 2>/dev/null
}
printf "┌────────┬───────┬───────┬──────────────┬"
printf "──────────────┬───────┬────────┐\n"
for type in gre vxlan geneve; do
if ! $(modprobe "$type" 2>/dev/null); then
continue
fi
for outer in 4 6; do
printf "├────────┼───────┼───────┼──────────────┼"
printf "──────────────┼───────┼────────┤\n"
printf "│ Type │ outer | inner │ tos │"
printf " ttl │ vlan │ result │\n"
for inner in 4 6 other; do
printf "├────────┼───────┼───────┼──────────────┼"
printf "──────────────┼───────┼────────┤\n"
for tos_ttl in inherit random; do
for vlan in false true; do
setup "$type" "$outer" "$inner" \
"$tos_ttl" "$vlan"
verify "$outer" "$inner" "$tos_ttl" \
"$vlan"
cleanup
done
done
done
done
done
printf "└────────┴───────┴───────┴──────────────┴"
printf "──────────────┴───────┴────────┘\n"
if $failed; then
exit 1
fi