linux-stable/include
Hangbin Liu 4b2b606075 ipv4/fib: send notify when delete source address routes
After deleting an interface address in fib_del_ifaddr(), the function
scans the fib_info list for stray entries and calls fib_flush() and
fib_table_flush(). Then the stray entries will be deleted silently and no
RTM_DELROUTE notification will be sent.

This lack of notification can make routing daemons, or monitor like
`ip monitor route` miss the routing changes. e.g.

+ 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 192.168.5.5/24 dev dummy1
+ ip route add 7.7.7.0/24 dev dummy2 src 192.168.5.5
+ ip -4 route
7.7.7.0/24 dev dummy2 scope link src 192.168.5.5
192.168.5.0/24 dev dummy1 proto kernel scope link src 192.168.5.5
+ ip monitor route
+ ip addr del 192.168.5.5/24 dev dummy1
Deleted 192.168.5.0/24 dev dummy1 proto kernel scope link src 192.168.5.5
Deleted broadcast 192.168.5.255 dev dummy1 table local proto kernel scope link src 192.168.5.5
Deleted local 192.168.5.5 dev dummy1 table local proto kernel scope host src 192.168.5.5

As Ido reminded, fib_table_flush() isn't only called when an address is
deleted, but also when an interface is deleted or put down. The lack of
notification in these cases is deliberate. And commit 7c6bb7d2fa
("net/ipv6: Add knob to skip DELROUTE message on device down") introduced
a sysctl to make IPv6 behave like IPv4 in this regard. So we can't send
the route delete notify blindly in fib_table_flush().

To fix this issue, let's add a new flag in "struct fib_info" to track the
deleted prefer source address routes, and only send notify for them.

After update:
+ ip monitor route
+ ip addr del 192.168.5.5/24 dev dummy1
Deleted 192.168.5.0/24 dev dummy1 proto kernel scope link src 192.168.5.5
Deleted broadcast 192.168.5.255 dev dummy1 table local proto kernel scope link src 192.168.5.5
Deleted local 192.168.5.5 dev dummy1 table local proto kernel scope host src 192.168.5.5
Deleted 7.7.7.0/24 dev dummy2 scope link src 192.168.5.5

Suggested-by: Thomas Haller <thaller@redhat.com>
Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
Acked-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Link: https://lore.kernel.org/r/20230922075508.848925-1-liuhangbin@gmail.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2023-10-03 09:00:40 +02:00
..
acpi
asm-generic ata changes for 6.6 2023-09-05 12:37:28 -07:00
clocksource
crypto
drm drm/tests: helpers: Avoid a driver uaf 2023-09-14 13:57:58 +02:00
dt-bindings IOMMU Updates for Linux v6.6 2023-09-01 16:54:25 -07:00
keys
kunit
kvm
linux Networking fixes for 6.6-rc2, including fixes from netfilter and bpf 2023-09-21 11:28:16 -07:00
math-emu
media media updates for v6.6-rc1 2023-09-01 12:21:32 -07:00
memory
misc
net ipv4/fib: send notify when delete source address routes 2023-10-03 09:00:40 +02:00
pcmcia
ras
rdma
rv rv: Set variable 'da_mon_##name' to static 2023-09-01 21:00:00 -04:00
scsi SCSI misc on 20230909 2023-09-09 12:01:33 -07:00
soc IOMMU Updates for Linux v6.6 2023-09-01 16:54:25 -07:00
sound ASoC: Name iov_iter argument as iterator instead of buffer 2023-09-01 15:38:49 +02:00
target
trace x86/xen: move paravirt lazy code 2023-09-19 07:04:49 +02:00
uapi Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf 2023-09-16 11:16:00 +01:00
ufs Merge branch 'fixes' into misc 2023-09-02 08:25:19 +01:00
vdso
video
xen arm/xen: remove lazy mode related definitions 2023-09-19 07:04:49 +02:00