selftests: fib_rule_tests: Add negative connect tests

The fib_rule{4,6}_connect tests verify that locally generated traffic
from a socket that specifies a DS Field using the IP_TOS / IPV6_TCLASS
socket options is correctly redirected using a FIB rule that matches on
the given DS Field.

Add negative tests to verify that the FIB rule is not hit when the
socket specifies a DS Field that differs from the one used by the FIB
rule.
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Link: https://patch.msgid.link/20240814111005.955359-5-idosch@nvidia.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

tools/testing/selftests/net/fib_rule_tests.sh

@@ -325,6 +325,16 @@ fib_rule6_connect_test()
 		log_test $? 0 "rule6 dsfield tcp connect (dsfield ${dsfield})"
 	done
 
+	# Check that UDP and TCP connections fail when using a DS Field that
+	# does not match the previously configured FIB rule.
+	nettest -q -6 -B -t 5 -N $testns -O $peerns -U -D \
+		-Q 0x20 -l 2001:db8::1:11 -r 2001:db8::1:11
+	log_test $? 1 "rule6 dsfield udp no connect (dsfield 0x20)"
+
+	nettest -q -6 -B -t 5 -N $testns -O $peerns -Q 0x20 \
+		-l 2001:db8::1:11 -r 2001:db8::1:11
+	log_test $? 1 "rule6 dsfield tcp no connect (dsfield 0x20)"
+
 	$IP -6 rule del dsfield 0x04 table $RTABLE_PEER
 	cleanup_peer
 }
@@ -502,6 +512,16 @@ fib_rule4_connect_test()
 		log_test $? 0 "rule4 dsfield tcp connect (dsfield ${dsfield})"
 	done
 
+	# Check that UDP and TCP connections fail when using a DS Field that
+	# does not match the previously configured FIB rule.
+	nettest -q -B -t 5 -N $testns -O $peerns -D -U -Q 0x20 \
+		-l 198.51.100.11 -r 198.51.100.11
+	log_test $? 1 "rule4 dsfield udp no connect (dsfield 0x20)"
+
+	nettest -q -B -t 5 -N $testns -O $peerns -Q 0x20 \
+		-l 198.51.100.11 -r 198.51.100.11
+	log_test $? 1 "rule4 dsfield tcp no connect (dsfield 0x20)"
+
 	$IP -4 rule del dsfield 0x04 table $RTABLE_PEER
 	cleanup_peer
 }