[PATCH v2 net-next 03/11] selftests: netfilter: nft_queue.sh: add udp fraglist gro test case

Florian Westphal
2026-02-06T15:31:12Z

Without the preceding patch, this fails with:

FAIL: test_udp_gro_ct: Expected udp conntrack entry
FAIL: test_udp_gro_ct: Expected software segmentation to occur, had 10 and 0

Signed-off-by: Florian Westphal <fw@strlen.de>
---
.../selftests/net/netfilter/nft_queue.sh | 142 +++++++++++++++++-
1 file changed, 136 insertions(+), 6 deletions(-)

diff --git a/tools/testing/selftests/net/netfilter/nft_queue.sh b/tools/testing/selftests/net/netfilter/nft_queue.sh
index 6136ceec45e0..139bc1211878 100755
--- a/tools/testing/selftests/net/netfilter/nft_queue.sh
+++ b/tools/testing/selftests/net/netfilter/nft_queue.sh
@@ -510,7 +510,7 @@ EOF

udp_listener_ready()
{
- ss -S -N "$1" -uln -o "sport = :12345" | grep -q 12345
+ ss -S -N "$1" -uln -o "sport = :$2" | grep -q "$2"
}

output_files_written()
@@ -518,7 +518,7 @@ output_files_written()
test -s "$1" && test -s "$2"
}

-test_udp_ct_race()
+test_udp_nat_race()
{
ip netns exec "$nsrouter" nft -f /dev/stdin <<EOF
flush ruleset
@@ -545,8 +545,8 @@ EOF
ip netns exec "$nsrouter" ./nf_queue -q 12 -d 1000 &
local nfqpid=$!

- busywait "$BUSYWAIT_TIMEOUT" udp_listener_ready "$ns2"
- busywait "$BUSYWAIT_TIMEOUT" udp_listener_ready "$ns3"
+ busywait "$BUSYWAIT_TIMEOUT" udp_listener_ready "$ns2" 12345
+ busywait "$BUSYWAIT_TIMEOUT" udp_listener_ready "$ns3" 12345
busywait "$BUSYWAIT_TIMEOUT" nf_queue_wait "$nsrouter" 12

# Send two packets, one should end up in ns1, other in ns2.
@@ -557,7 +557,7 @@ EOF

busywait 10000 output_files_written "$TMPFILE1" "$TMPFILE2"

- kill "$nfqpid"
+ kill "$nfqpid" "$rpid1" "$rpid2"

if ! ip netns exec "$nsrouter" bash -c 'conntrack -L -p udp --dport 12345 2>/dev/null | wc -l | grep -q "^1"'; then
echo "FAIL: Expected One udp conntrack entry"
@@ -585,6 +585,135 @@ EOF
echo "PASS: both udp receivers got one packet each"
}

+# Make sure UDPGRO aggregated packets don't lose
+# their skb->nfct entry when nfqueue passes the
+# skb to userspace with software gso segmentation on.
+test_udp_gro_ct()
+{
+ local errprefix="FAIL: test_udp_gro_ct:"
+
+ ip netns exec "$nsrouter" conntrack -F 2>/dev/null
+
+ ip netns exec "$nsrouter" nft -f /dev/stdin <<EOF
+flush ruleset
+table inet udpq {
+ # Number of packets/bytes queued to userspace
+ counter toqueue { }
+ # Number of packets/bytes reinjected from userspace with 'ct new' intact
+ counter fromqueue { }
+ # These two counters should be identical and not 0.
+
+ chain prerouting {
+ type filter hook prerouting priority -300; policy accept;
+
+ # userspace sends small packets, if < 1000, UDPGRO did
+ # not kick in, but test needs a 'new' conntrack with udpgro skb.
+ meta iifname veth0 meta l4proto udp meta length > 1000 accept
+
+ # don't pick up non-gso packets and don't queue them to
+ # userspace.
+ notrack
+ }
+
+ chain postrouting {
+ type filter hook postrouting priority 0; policy accept;
+
+ # Only queue unconfirmed fraglist gro skbs to userspace.
+ udp dport 12346 ct status ! confirmed counter name "toqueue" mark set 1 queue num 1
+ }
+
+ chain validate {
+ type filter hook postrouting priority 1; policy accept;
+ # ... and only count those that were reinjected with the
+ # skb->nfct intact.
+ mark 1 counter name "fromqueue"
+ }
+}
+EOF
+ timeout 10 ip netns exec "$ns2" socat UDP-LISTEN:12346,fork,pf=ipv4 OPEN:"$TMPFILE1",trunc &
+ local rpid=$!
+
+ ip netns exec "$nsrouter" ./nf_queue -G -c -q 1 -t 2 > "$TMPFILE2" &
+ local nfqpid=$!
+
+ ip netns exec "$nsrouter" ethtool -K "veth0" rx-udp-gro-forwarding on rx-gro-list on generic-receive-offload on
+
+ busywait "$BUSYWAIT_TIMEOUT" udp_listener_ready "$ns2" 12346
+ busywait "$BUSYWAIT_TIMEOUT" nf_queue_wait "$nsrouter" 1
+
+ local bs=512
+ local count=$(((32 * 1024 * 1024) / bs))
+ dd if=/dev/zero bs="$bs" count="$count" 2>/dev/null | for i in $(seq 1 16); do
+ timeout 5 ip netns exec "$ns1" \
+ socat -u -b 512 STDIN UDP-DATAGRAM:10.0.2.99:12346,reuseport,bind=0.0.0.0:55221 &
+ done
+
+ busywait 10000 test -s "$TMPFILE1"
+
+ kill "$rpid"
+
+ wait
+
+ local p
+ local b
+ local pqueued
+ local bqueued
+
+ c=$(ip netns exec "$nsrouter" nft list counter inet udpq "toqueue" | grep packets)
+ read p pqueued b bqueued <<EOF
+$c
+EOF
+ local preinject
+ local breinject
+ c=$(ip netns exec "$nsrouter" nft list counter inet udpq "fromqueue" | grep packets)
+ read p preinject b breinject <<EOF
+$c
+EOF
+ ip netns exec "$nsrouter" ethtool -K "veth0" rx-udp-gro-forwarding off
+ ip netns exec "$nsrouter" ethtool -K "veth1" rx-udp-gro-forwarding off
+
+ if [ "$pqueued" -eq 0 ];then
+ # happens when gro did not build at least on aggregate
+ echo "SKIP: No packets were queued"
+ return
+ fi
+
+ local saw_ct_entry=0
+ if ip netns exec "$nsrouter" bash -c 'conntrack -L -p udp --dport 12346 2>/dev/null | wc -l | grep -q "^1"'; then
+ saw_ct_entry=1
+ else
+ echo "$errprefix Expected udp conntrack entry"
+ ip netns exec "$nsrouter" conntrack -L
+ ret=1
+ fi
+
+ if [ "$pqueued" -ge "$preinject" ] ;then
+ echo "$errprefix Expected software segmentation to occur, had $pqueued and $preinject"
+ ret=1
+ return
+ fi
+
+ # sw segmentation adds extra udp and ip headers.
+ local breinject_expect=$((preinject * (512 + 20 + 8)))
+
+ if [ "$breinject" -eq "$breinject_expect" ]; then
+ if [ "$saw_ct_entry" -eq 1 ];then
+ echo "PASS: fraglist gro skb passed with conntrack entry"
+ else
+ echo "$errprefix fraglist gro skb passed without conntrack entry"
+ ret=1
+ fi
+ else
+ echo "$errprefix Counter mismatch, conntrack entry dropped by nfqueue? Queued: $pqueued, $bqueued. Post-queue: $preinject, $breinject. Expected $breinject_expect"
+ ret=1
+ fi
+
+ if ! ip netns exec "$nsrouter" nft delete table inet udpq; then
+ echo "$errprefix: Could not delete udpq table"
+ ret=1
+ fi
+}
+
test_queue_removal()
{
read tainted_then < /proc/sys/kernel/tainted
@@ -663,7 +792,8 @@ test_tcp_localhost_connectclose
test_tcp_localhost_requeue
test_sctp_forward
test_sctp_output
-test_udp_ct_race
+test_udp_nat_race
+test_udp_gro_ct

# should be last, adds vrf device in ns1 and changes routes
test_icmp_vrf
--
2.52.0