[PATCHv3 net] ipv6: do not match device when remove source route

Hangbin Liu
2023-07-20T06:59:57Z

After deleting an IPv6 address on an interface and cleaning up the
related preferred source entries, it is important to ensure that all
routes associated with the deleted address are properly cleared. The
current implementation of rt6_remove_prefsrc() only checks the preferred
source addresses bound to the current device. However, there may be
routes that are bound to other devices but still utilize the same
preferred source address.

To address this issue, it is necessary to also delete entries that are
bound to other interfaces but share the same source address with the
current device. Failure to delete these entries would leave routes that
are bound to the deleted address unclear. Here is an example reproducer
(I have omitted unrelated routes):

+ ip link add dummy1 type dummy
+ ip link add dummy2 type dummy
+ ip link set dummy1 up
+ ip link set dummy2 up
+ ip addr add 1:2:3:4::5/64 dev dummy1
+ ip route add 7:7:7:0::1 dev dummy1 src 1:2:3:4::5
+ ip route add 7:7:7:0::2 dev dummy2 src 1:2:3:4::5
+ ip -6 route show
1:2:3:4::/64 dev dummy1 proto kernel metric 256 pref medium
7:7:7::1 dev dummy1 src 1:2:3:4::5 metric 1024 pref medium
7:7:7::2 dev dummy2 src 1:2:3:4::5 metric 1024 pref medium
+ ip addr del 1:2:3:4::5/64 dev dummy1
+ ip -6 route show
7:7:7::1 dev dummy1 metric 1024 pref medium
7:7:7::2 dev dummy2 src 1:2:3:4::5 metric 1024 pref medium

After fix:

+ ip addr del 1:2:3:4::5/64 dev dummy1
+ ip -6 route show
7:7:7::1 dev dummy1 metric 1024 pref medium
7:7:7::2 dev dummy2 metric 1024 pref medium

Ido notified that there is a commit 5a56a0b3a45d ("net: Don't delete
routes in different VRFs") to not affect the route in different VRFs.
So let's remove the rt dev checking and add an table id checking.
Also remove the !rt-nh checking to clear the IPv6 routes that are using
a nexthop object. This would be consistent with IPv4.

A ipv6_del_addr test is added for fib_tests.sh. Note that instead
of removing the whole route for IPv4, IPv6 only remove the preferred
source address for source routing. So in the testing use
"grep -q src $src_ipv6_address" instead of "grep -q $dst_ipv6_subnet/64"
when checking if the source route deleted.

Here is the fib_tests.sh ipv6_del_addr test result.

Before fix:
IPv6 delete address route tests
Regular FIB info
TEST: Prefsrc removed from VRF when source address deleted [ OK ]
TEST: Prefsrc in default VRF not removed [FAIL]
TEST: Prefsrc removed in default VRF when source address deleted [ OK ]
TEST: Prefsrc in VRF is not removed by address delete [FAIL]
Identical FIB info with different table ID
TEST: Prefsrc removed from VRF when source address deleted [ OK ]
TEST: Prefsrc in default VRF not removed [FAIL]
TEST: Prefsrc removed in default VRF when source address deleted [ OK ]
TEST: Prefsrc in VRF is not removed by address delete [FAIL]
Table ID 0
TEST: Prefsrc removed in default VRF when source address deleted [ OK ]

After fix:
IPv6 delete address route tests
Regular FIB info
TEST: Prefsrc removed from VRF when source address deleted [ OK ]
TEST: Prefsrc in default VRF not removed [ OK ]
TEST: Prefsrc removed in default VRF when source address deleted [ OK ]
TEST: Prefsrc in VRF is not removed by address delete [ OK ]
Identical FIB info with different table ID
TEST: Prefsrc removed from VRF when source address deleted [ OK ]
TEST: Prefsrc in default VRF not removed [ OK ]
TEST: Prefsrc removed in default VRF when source address deleted [ OK ]
TEST: Prefsrc in VRF is not removed by address delete [ OK ]
Table ID 0
TEST: Prefsrc removed in default VRF when source address deleted [ OK ]

Reported-by: Thomas Haller <thaller@redhat.com>
Fixes: c3968a857a6b ("ipv6: RTA_PREFSRC support for ipv6 route source address selection")
Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
---
v3: remove rt nh checking. update the ipv6_del_addr test descriptions
v2: checking table id and update fib_test.sh
---
net/ipv6/route.c | 6 +-
tools/testing/selftests/net/fib_tests.sh | 93 +++++++++++++++++++++++-
2 files changed, 95 insertions(+), 4 deletions(-)

diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index 64e873f5895f..773285adc17c 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -4590,10 +4590,10 @@ static int fib6_remove_prefsrc(struct fib6_info *rt, void *arg)
struct net_device *dev = ((struct arg_dev_net_ip *)arg)->dev;
struct net *net = ((struct arg_dev_net_ip *)arg)->net;
struct in6_addr *addr = ((struct arg_dev_net_ip *)arg)->addr;
+ u32 tb6_id = l3mdev_fib_table(dev) ? : RT_TABLE_MAIN;

- if (!rt->nh &&
- ((void *)rt->fib6_nh->fib_nh_dev == dev || !dev) &&
- rt != net->ipv6.fib6_null_entry &&
+ if (rt != net->ipv6.fib6_null_entry &&
+ rt->fib6_table->tb6_id == tb6_id &&
ipv6_addr_equal(addr, &rt->fib6_prefsrc.addr)) {
spin_lock_bh(&rt6_exception_lock);
/* remove prefsrc entry */
diff --git a/tools/testing/selftests/net/fib_tests.sh b/tools/testing/selftests/net/fib_tests.sh
index 35d89dfa6f11..bf11edc17dfc 100755
--- a/tools/testing/selftests/net/fib_tests.sh
+++ b/tools/testing/selftests/net/fib_tests.sh
@@ -9,7 +9,7 @@ ret=0
ksft_skip=4

# all tests in this script. Can be overridden with -t option
-TESTS="unregister down carrier nexthop suppress ipv6_notify ipv4_notify ipv6_rt ipv4_rt ipv6_addr_metric ipv4_addr_metric ipv6_route_metrics ipv4_route_metrics ipv4_route_v6_gw rp_filter ipv4_del_addr ipv4_mangle ipv6_mangle ipv4_bcast_neigh"
+TESTS="unregister down carrier nexthop suppress ipv6_notify ipv4_notify ipv6_rt ipv4_rt ipv6_addr_metric ipv4_addr_metric ipv6_route_metrics ipv4_route_metrics ipv4_route_v6_gw rp_filter ipv4_del_addr ipv6_del_addr ipv4_mangle ipv6_mangle ipv4_bcast_neigh"

VERBOSE=0
PAUSE_ON_FAIL=no
@@ -1869,6 +1869,96 @@ ipv4_del_addr_test()
cleanup
}

+ipv6_del_addr_test()
+{
+ echo
+ echo "IPv6 delete address route tests"
+
+ setup
+
+ set -e
+ $IP li add dummy1 type dummy
+ $IP li set dummy1 up
+ $IP li add dummy2 type dummy
+ $IP li set dummy2 up
+ $IP li add red type vrf table 1111
+ $IP li set red up
+ $IP ro add vrf red unreachable default
+ $IP li set dummy2 vrf red
+
+ $IP addr add dev dummy1 2001:db8:104::1/64
+ $IP addr add dev dummy1 2001:db8:104::11/64
+ $IP addr add dev dummy1 2001:db8:104::12/64
+ $IP addr add dev dummy1 2001:db8:104::13/64
+ $IP addr add dev dummy2 2001:db8:104::1/64
+ $IP addr add dev dummy2 2001:db8:104::11/64
+ $IP addr add dev dummy2 2001:db8:104::12/64
+ $IP route add 2001:db8:105::/64 via 2001:db8:104::2 src 2001:db8:104::11
+ $IP route add 2001:db8:106::/64 dev lo src 2001:db8:104::12
+ $IP route add table 0 2001:db8:107::/64 via 2001:db8:104::2 src 2001:db8:104::13
+ $IP route add vrf red 2001:db8:105::/64 via 2001:db8:104::2 src 2001:db8:104::11
+ $IP route add vrf red 2001:db8:106::/64 dev lo src 2001:db8:104::12
+ set +e
+
+ # removing address from device in vrf should only remove it as a
+ # preferred source address from routes in vrf table
+ echo " Regular FIB info"
+
+ $IP addr del dev dummy2 2001:db8:104::11/64
+ # Checking if the source address exists instead of the dest subnet
+ # as IPv6 only removes the preferred source address, not whole route.
+ $IP -6 ro ls vrf red | grep -q "src 2001:db8:104::11"
+ log_test $? 1 "Prefsrc removed from VRF when source address deleted"
+
+ $IP -6 ro ls | grep -q " src 2001:db8:104::11"
+ log_test $? 0 "Prefsrc in default VRF not removed"
+
+ $IP addr add dev dummy2 2001:db8:104::11/64
+ $IP route replace vrf red 2001:db8:105::/64 via 2001:db8:104::2 src 2001:db8:104::11
+
+ $IP addr del dev dummy1 2001:db8:104::11/64
+ $IP -6 ro ls | grep -q "src 2001:db8:104::11"
+ log_test $? 1 "Prefsrc removed in default VRF when source address deleted"
+
+ $IP -6 ro ls vrf red | grep -q "src 2001:db8:104::11"
+ log_test $? 0 "Prefsrc in VRF is not removed by address delete"
+
+ # removing address from device in vrf should only remove preferred
+ # source address 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 2001:db8:104::12/64
+ $IP -6 ro ls vrf red | grep -q "src 2001:db8:104::12"
+ log_test $? 1 "Prefsrc removed from VRF when source address deleted"
+
+ $IP -6 ro ls | grep -q "src 2001:db8:104::12"
+ log_test $? 0 "Prefsrc in default VRF not removed"
+
+ $IP addr add dev dummy2 2001:db8:104::12/64
+ $IP route replace vrf red 2001:db8:106::/64 dev lo src 2001:db8:104::12
+
+ $IP addr del dev dummy1 2001:db8:104::12/64
+ $IP -6 ro ls | grep -q "src 2001:db8:104::12"
+ log_test $? 1 "Prefsrc removed in default VRF when source address deleted"
+
+ $IP -6 ro ls vrf red | grep -q "src 2001:db8:104::12"
+ log_test $? 0 "Prefsrc in VRF is not removed by address delete"
+
+ # removing address from device in default vrf should remove preferred
+ # source address from the default vrf even when route was inserted
+ # with a table ID of 0.
+ echo " Table ID 0"
+
+ $IP addr del dev dummy1 2001:db8:104::13/64
+ $IP -6 ro ls | grep -q "src 2001:db8:104::13"
+ log_test $? 1 "Prefsrc removed in default VRF when source address deleted"
+
+ $IP li del dummy1
+ $IP li del dummy2
+ cleanup
+}
+

ipv4_route_v6_gw_test()
{
@@ -2211,6 +2301,7 @@ do
ipv6_addr_metric) ipv6_addr_metric_test;;
ipv4_addr_metric) ipv4_addr_metric_test;;
ipv4_del_addr) ipv4_del_addr_test;;
+ ipv6_del_addr) ipv6_del_addr_test;;
ipv6_route_metrics) ipv6_route_metrics_test;;
ipv4_route_metrics) ipv4_route_metrics_test;;
ipv4_route_v6_gw) ipv4_route_v6_gw_test;;
--
2.38.1