selftests: forwarding: Add test cases for unresolved multicast routes

Add IPv4 and IPv6 test cases for unresolved multicast routes, testing
that queued packets are forwarded after installing a matching (S, G)
route.

The test cases can be used to reproduce the bugs fixed in "ipmr: Always
call ip{,6}_mr_forward() from RCU read-side critical section".

Signed-off-by: Ido Schimmel <[e-mail]>
Signed-off-by: Jakub Kicinski <[e-mail]>

tools/testing/selftests/net/forwarding/router_multicast.sh

···
 # +------------------+       +------------------+
 #
 
-ALL_TESTS="mcast_v4 mcast_v6 rpf_v4 rpf_v6"
+ALL_TESTS="mcast_v4 mcast_v6 rpf_v4 rpf_v6 unres_v4 unres_v6"
 NUM_NETIFS=6
 source lib.sh
 source tc_common.sh
···
 	tc filter del dev $h1 ingress protocol ipv6 pref 1 handle 1 flower
 
 	log_test "RPF IPv6"
+}
+
+unres_v4()
+{
+	# Send a multicast packet not corresponding to an installed route,
+	# causing the kernel to queue the packet for resolution and emit an
+	# IGMPMSG_NOCACHE notification. smcrouted will react to this
+	# notification by consulting its (*, G) list and installing an (S, G)
+	# route, which will be used to forward the queued packet.
+
+	RET=0
+
+	tc filter add dev $h2 ingress protocol ip pref 1 handle 1 flower \
+		dst_ip 225.1.2.3 ip_proto udp dst_port 12345 action drop
+	tc filter add dev $h3 ingress protocol ip pref 1 handle 1 flower \
+		dst_ip 225.1.2.3 ip_proto udp dst_port 12345 action drop
+
+	# Forwarding should fail before installing a matching (*, G).
+	$MZ $h1 -c 1 -p 128 -t udp "ttl=10,sp=54321,dp=12345" \
+		-a 00:11:22:33:44:55 -b 01:00:5e:01:02:03 \
+		-A 198.51.100.2 -B 225.1.2.3 -q
+
+	tc_check_packets "dev $h2 ingress" 1 0
+	check_err $? "Multicast received on first host when should not"
+	tc_check_packets "dev $h3 ingress" 1 0
+	check_err $? "Multicast received on second host when should not"
+
+	# Create (*, G). Will not be installed in the kernel.
+	create_mcast_sg $rp1 0.0.0.0 225.1.2.3 $rp2 $rp3
+
+	$MZ $h1 -c 1 -p 128 -t udp "ttl=10,sp=54321,dp=12345" \
+		-a 00:11:22:33:44:55 -b 01:00:5e:01:02:03 \
+		-A 198.51.100.2 -B 225.1.2.3 -q
+
+	tc_check_packets "dev $h2 ingress" 1 1
+	check_err $? "Multicast not received on first host"
+	tc_check_packets "dev $h3 ingress" 1 1
+	check_err $? "Multicast not received on second host"
+
+	delete_mcast_sg $rp1 0.0.0.0 225.1.2.3 $rp2 $rp3
+
+	tc filter del dev $h3 ingress protocol ip pref 1 handle 1 flower
+	tc filter del dev $h2 ingress protocol ip pref 1 handle 1 flower
+
+	log_test "Unresolved queue IPv4"
+}
+
+unres_v6()
+{
+	# Send a multicast packet not corresponding to an installed route,
+	# causing the kernel to queue the packet for resolution and emit an
+	# MRT6MSG_NOCACHE notification. smcrouted will react to this
+	# notification by consulting its (*, G) list and installing an (S, G)
+	# route, which will be used to forward the queued packet.
+
+	RET=0
+
+	tc filter add dev $h2 ingress protocol ipv6 pref 1 handle 1 flower \
+		dst_ip ff0e::3 ip_proto udp dst_port 12345 action drop
+	tc filter add dev $h3 ingress protocol ipv6 pref 1 handle 1 flower \
+		dst_ip ff0e::3 ip_proto udp dst_port 12345 action drop
+
+	# Forwarding should fail before installing a matching (*, G).
+	$MZ $h1 -6 -c 1 -p 128 -t udp "ttl=10,sp=54321,dp=12345" \
+		-a 00:11:22:33:44:55 -b 33:33:00:00:00:03 \
+		-A 2001:db8:1::2 -B ff0e::3 -q
+
+	tc_check_packets "dev $h2 ingress" 1 0
+	check_err $? "Multicast received on first host when should not"
+	tc_check_packets "dev $h3 ingress" 1 0
+	check_err $? "Multicast received on second host when should not"
+
+	# Create (*, G). Will not be installed in the kernel.
+	create_mcast_sg $rp1 :: ff0e::3 $rp2 $rp3
+
+	$MZ $h1 -6 -c 1 -p 128 -t udp "ttl=10,sp=54321,dp=12345" \
+		-a 00:11:22:33:44:55 -b 33:33:00:00:00:03 \
+		-A 2001:db8:1::2 -B ff0e::3 -q
+
+	tc_check_packets "dev $h2 ingress" 1 1
+	check_err $? "Multicast not received on first host"
+	tc_check_packets "dev $h3 ingress" 1 1
+	check_err $? "Multicast not received on second host"
+
+	delete_mcast_sg $rp1 :: ff0e::3 $rp2 $rp3
+
+	tc filter del dev $h3 ingress protocol ipv6 pref 1 handle 1 flower
+	tc filter del dev $h2 ingress protocol ipv6 pref 1 handle 1 flower
+
+	log_test "Unresolved queue IPv6"
 }
 
 trap cleanup EXIT