[PATCH net v2 3/4] selftests: net: test restricted on-link fallback

[liamsmith827 <liamsmith827@grapheneos.org>]

From: liamsmith827 <liamsmith827@proton.me>

Update tests now that the on-link fallback has been restricted to
routing lookup misses for non-vrf unicast.

Cc: stable@vger.kernel.org
Signed-off-by: liamsmith827 <liamsmith827@proton.me>
---
 tools/testing/selftests/net/fcnal-test.sh | 47 +++++++++++++----------
 1 file changed, 26 insertions(+), 21 deletions(-)

diff --git a/tools/testing/selftests/net/fcnal-test.sh b/tools/testing/selftests/net/fcnal-test.sh
index a50609535fed..c048d5be139d 100755
--- a/tools/testing/selftests/net/fcnal-test.sh
+++ b/tools/testing/selftests/net/fcnal-test.sh
@@ -619,17 +619,29 @@ ipv4_ping_novrf()
 	run_cmd ping -c1 -w1 -I ${NSA_DEV} ${a}
 	log_test_addr ${a} $? 0 "ping local, device bind"
 
-	# loopback addresses not reachable from device bind
-	# fails in a really weird way though because ipv4 special cases
-	# route lookups with oif set.
+	# loopback addresses not reachable from device bind, unreachable default route
 	for a in ${NSA_LO_IP} 127.0.0.1
 	do
 		log_start
 		show_hint "Fails since address on loopback device is out of device scope"
 		run_cmd ping -c1 -w1 -I ${NSA_DEV} ${a}
-		log_test_addr ${a} $? 1 "ping local, device bind"
+		log_test_addr ${a} $? 2 "ping local, device bind, unreachable default route"
 	done
 
+	# loopback addresses not reachable from device bind, route miss
+	log_start
+	setup_cmd ip route del unreachable default metric 8192
+
+	for a in ${NSA_LO_IP} 127.0.0.1
+	do
+		log_start
+		show_hint "Fails since address on loopback device is out of device scope"
+		run_cmd ping -c1 -w1 -I ${NSA_DEV} ${a}
+		log_test_addr ${a} $? 1 "ping local, device bind, route miss"
+	done
+
+	setup_cmd ip route add unreachable default metric 8192
+
 	#
 	# ip rule blocks reachability to remote address
 	#
@@ -643,10 +655,9 @@ ipv4_ping_novrf()
 	run_cmd ping -c1 -w1 ${a}
 	log_test_addr ${a} $? 2 "ping out, blocked by rule"
 
-	# NOTE: ipv4 actually allows the lookup to fail and yet still create
-	# a viable rtable if the oif (e.g., bind to device) is set, so this
-	# case succeeds despite the rule
-	# run_cmd ping -c1 -w1 -I ${NSA_DEV} ${a}
+	log_start
+	run_cmd ping -c1 -w1 -I ${NSA_DEV} ${a}
+	log_test_addr ${a} $? 2 "ping out, device bind, blocked by rule"
 
 	a=${NSA_LO_IP}
 	log_start
@@ -671,10 +682,9 @@ ipv4_ping_novrf()
 	run_cmd ping -c1 -w1 ${a}
 	log_test_addr ${a} $? 2 "ping out, blocked by route"
 
-	# NOTE: ipv4 actually allows the lookup to fail and yet still create
-	# a viable rtable if the oif (e.g., bind to device) is set, so this
-	# case succeeds despite not having a route for the address
-	# run_cmd ping -c1 -w1 -I ${NSA_DEV} ${a}
+	log_start
+	run_cmd ping -c1 -w1 -I ${NSA_DEV} ${a}
+	log_test_addr ${a} $? 2 "ping out, device bind, blocked by route"
 
 	a=${NSA_LO_IP}
 	log_start
@@ -692,10 +702,9 @@ ipv4_ping_novrf()
 	run_cmd ping -c1 -w1 ${a}
 	log_test_addr ${a} $? 2 "ping out, unreachable default route"
 
-	# NOTE: ipv4 actually allows the lookup to fail and yet still create
-	# a viable rtable if the oif (e.g., bind to device) is set, so this
-	# case succeeds despite not having a route for the address
-	# run_cmd ping -c1 -w1 -I ${NSA_DEV} ${a}
+	log_start
+	run_cmd ping -c1 -w1 -I ${NSA_DEV} ${a}
+	log_test_addr ${a} $? 2 "ping out, device bind, unreachable default route"
 }
 
 ipv4_ping_vrf()
@@ -1602,10 +1611,6 @@ ipv4_udp_novrf()
 	run_cmd nettest -D -d ${NSA_DEV} -S -r ${a} -U
 	log_test_addr ${a} $? 0 "Global server, device client via IP_UNICAST_IF, local connection, with connect()"
 
-
-	# IPv4 with device bind has really weird behavior - it overrides the
-	# fib lookup, generates an rtable and tries to send the packet. This
-	# causes failures for local traffic at different places
 	for a in ${NSA_LO_IP} 127.0.0.1
 	do
 		log_start
@@ -1613,7 +1618,7 @@ ipv4_udp_novrf()
 		run_cmd nettest -D -s &
 		wait_local_port_listen ${NSA} 12345 udp
 		run_cmd nettest -D -r ${a} -d ${NSA_DEV}
-		log_test_addr ${a} $? 2 "Global server, device client, local connection"
+		log_test_addr ${a} $? 1 "Global server, device client, local connection"
 
 		log_start
 		show_hint "Should fail since addresses on loopback are out of device scope"
-- 
2.47.3