ipv4: Fix incorrect route flushing when source address is deleted

Cited commit added the table ID to the FIB info structure, but did not
prevent structures with different table IDs from being consolidated.
This can lead to routes being flushed from a VRF when an address is
deleted from a different VRF.

Fix by taking the table ID into account when looking for a matching FIB
info. This is already done for FIB info structures backed by a nexthop
object in fib_find_info_nh().

Add test cases that fail before the fix:

 # ./fib_tests.sh -t ipv4_del_addr

 IPv4 delete address route tests
     Regular FIB info
     TEST: Route removed from VRF when source address deleted            [ OK ]
     TEST: Route in default VRF not removed                              [ OK ]
     TEST: Route removed in default VRF when source address deleted      [ OK ]
     TEST: Route in VRF is not removed by address delete                 [ OK ]
     Identical FIB info with different table ID
     TEST: Route removed from VRF when source address deleted            [FAIL]
     TEST: Route in default VRF not removed                              [ OK ]
 RTNETLINK answers: File exists
     TEST: Route removed in default VRF when source address deleted      [ OK ]
     TEST: Route in VRF is not removed by address delete                 [FAIL]

 Tests passed:   6
 Tests failed:   2

And pass after:

 # ./fib_tests.sh -t ipv4_del_addr

 IPv4 delete address route tests
     Regular FIB info
     TEST: Route removed from VRF when source address deleted            [ OK ]
     TEST: Route in default VRF not removed                              [ OK ]
     TEST: Route removed in default VRF when source address deleted      [ OK ]
     TEST: Route in VRF is not removed by address delete                 [ OK ]
     Identical FIB info with different table ID
     TEST: Route removed from VRF when source address deleted            [ OK ]
     TEST: Route in default VRF not removed                              [ OK ]
     TEST: Route removed in default VRF when source address deleted      [ OK ]
     TEST: Route in VRF is not removed by address delete                 [ OK ]

 Tests passed:   8
 Tests failed:   0

Fixes: 5a56a0b ("net: Don't delete routes in different VRFs")
Signed-off-by: Ido Schimmel <[email protected]>
Reviewed-by: David Ahern <[email protected]>
Signed-off-by: Jakub Kicinski <[email protected]>

Author: idosch

net/ipv4/fib_semantics.c

@@ -423,6 +423,7 @@ static struct fib_info *fib_find_info(struct fib_info *nfi)
 		    nfi->fib_prefsrc == fi->fib_prefsrc &&
 		    nfi->fib_priority == fi->fib_priority &&
 		    nfi->fib_type == fi->fib_type &&
+		    nfi->fib_tb_id == fi->fib_tb_id &&
 		    memcmp(nfi->fib_metrics, fi->fib_metrics,
 			   sizeof(u32) * RTAX_MAX) == 0 &&
 		    !((nfi->fib_flags ^ fi->fib_flags) & ~RTNH_COMPARE_MASK) &&

tools/testing/selftests/net/fib_tests.sh

@@ -1711,13 +1711,19 @@ ipv4_del_addr_test()
 
 	$IP addr add dev dummy1 172.16.104.1/24
 	$IP addr add dev dummy1 172.16.104.11/24
+	$IP addr add dev dummy1 172.16.104.12/24
 	$IP addr add dev dummy2 172.16.104.1/24
 	$IP addr add dev dummy2 172.16.104.11/24
+	$IP addr add dev dummy2 172.16.104.12/24
 	$IP route add 172.16.105.0/24 via 172.16.104.2 src 172.16.104.11
+	$IP route add 172.16.106.0/24 dev lo src 172.16.104.12
 	$IP route add vrf red 172.16.105.0/24 via 172.16.104.2 src 172.16.104.11
+	$IP route add vrf red 172.16.106.0/24 dev lo src 172.16.104.12
 	set +e
 
 	# removing address from device in vrf should only remove route from vrf table
+	echo "    Regular FIB info"
+
 	$IP addr del dev dummy2 172.16.104.11/24
 	$IP ro ls vrf red | grep -q 172.16.105.0/24
 	log_test $? 1 "Route removed from VRF when source address deleted"
@@ -1735,6 +1741,27 @@ ipv4_del_addr_test()
 	$IP ro ls vrf red | grep -q 172.16.105.0/24
 	log_test $? 0 "Route in VRF is not removed by address delete"
 
+	# removing address from device in vrf should only remove route from vrf
+	# table even when the associated fib info only differs in table ID
+	echo "    Identical FIB info with different table ID"
+
+	$IP addr del dev dummy2 172.16.104.12/24
+	$IP ro ls vrf red | grep -q 172.16.106.0/24
+	log_test $? 1 "Route removed from VRF when source address deleted"
+
+	$IP ro ls | grep -q 172.16.106.0/24
+	log_test $? 0 "Route in default VRF not removed"
+
+	$IP addr add dev dummy2 172.16.104.12/24
+	$IP route add vrf red 172.16.106.0/24 dev lo src 172.16.104.12
+
+	$IP addr del dev dummy1 172.16.104.12/24
+	$IP ro ls | grep -q 172.16.106.0/24
+	log_test $? 1 "Route removed in default VRF when source address deleted"
+
+	$IP ro ls vrf red | grep -q 172.16.106.0/24
+	log_test $? 0 "Route in VRF is not removed by address delete"
+
 	$IP li del dummy1
 	$IP li del dummy2
 	cleanup