linux-toradex.git/net/ipv4/fib_frontend.c, branch v6.6-rc1

ipv4: Fix incorrect table ID in IOCTL path

2023-03-17T00:26:31+00:00

Commit f96a3d74554d ("ipv4: Fix incorrect route flushing when source
address is deleted") started to take the table ID field in the FIB info
structure into account when determining if two structures are identical
or not. This field is initialized using the 'fc_table' field in the
route configuration structure, which is not set when adding a route via
IOCTL.

The above can result in user space being able to install two identical
routes that only differ in the table ID field of their associated FIB
info.

Fix by initializing the table ID field in the route configuration
structure in the IOCTL path.

Before the fix:

 # ip route add default via 192.0.2.2
 # route add default gw 192.0.2.2
 # ip -4 r show default
 # default via 192.0.2.2 dev dummy10
 # default via 192.0.2.2 dev dummy10

After the fix:

 # ip route add default via 192.0.2.2
 # route add default gw 192.0.2.2
 SIOCADDRT: File exists
 # ip -4 r show default
 default via 192.0.2.2 dev dummy10

Audited the code paths to ensure there are no other paths that do not
properly initialize the route configuration structure when installing a
route.

Fixes: 5a56a0b3a45d ("net: Don't delete routes in different VRFs")
Fixes: f96a3d74554d ("ipv4: Fix incorrect route flushing when source address is deleted")
Reported-by: gaoxingwang 
Link: https://lore.kernel.org/netdev/20230314144159.2354729-1-gaoxingwang1@huawei.com/
Tested-by: gaoxingwang 
Signed-off-by: Ido Schimmel 
Reviewed-by: David Ahern 
Link: https://lore.kernel.org/r/20230315124009.4015212-1-idosch@nvidia.com
Signed-off-by: Jakub Kicinski

ipv4: Fix incorrect route flushing when table ID 0 is used

2022-12-07T04:34:43+00:00

Cited commit added the table ID to the FIB info structure, but did not
properly initialize it when table ID 0 is used. This can lead to a route
in the default VRF with a preferred source address not being flushed
when the address is deleted.

Consider the following example:

 # ip address add dev dummy1 192.0.2.1/28
 # ip address add dev dummy1 192.0.2.17/28
 # ip route add 198.51.100.0/24 via 192.0.2.2 src 192.0.2.17 metric 100
 # ip route add table 0 198.51.100.0/24 via 192.0.2.2 src 192.0.2.17 metric 200
 # ip route show 198.51.100.0/24
 198.51.100.0/24 via 192.0.2.2 dev dummy1 src 192.0.2.17 metric 100
 198.51.100.0/24 via 192.0.2.2 dev dummy1 src 192.0.2.17 metric 200

Both routes are installed in the default VRF, but they are using two
different FIB info structures. One with a metric of 100 and table ID of
254 (main) and one with a metric of 200 and table ID of 0. Therefore,
when the preferred source address is deleted from the default VRF,
the second route is not flushed:

 # ip address del dev dummy1 192.0.2.17/28
 # ip route show 198.51.100.0/24
 198.51.100.0/24 via 192.0.2.2 dev dummy1 src 192.0.2.17 metric 200

Fix by storing a table ID of 254 instead of 0 in the route configuration
structure.

Add a test case that fails 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            [ 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 ]
     Table ID 0
     TEST: Route removed in default VRF when source address deleted      [FAIL]

 Tests passed:   8
 Tests failed:   1

And passes 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 ]
     Table ID 0
     TEST: Route removed in default VRF when source address deleted      [ OK ]

 Tests passed:   9
 Tests failed:   0

Fixes: 5a56a0b3a45d ("net: Don't delete routes in different VRFs")
Reported-by: Donald Sharp 
Signed-off-by: Ido Schimmel 
Reviewed-by: David Ahern 
Signed-off-by: Jakub Kicinski

Revert "ip: fix triggering of 'icmp redirect'"

2022-10-27T17:17:32+00:00

This reverts commit eb55dc09b5dd040232d5de32812cc83001a23da6.

The patch that introduces this bug is reverted right after this one.

Signed-off-by: Nicolas Dichtel 
Reviewed-by: Julian Anastasov 
Signed-off-by: Jakub Kicinski

ip: fix triggering of 'icmp redirect'

2022-09-01T02:50:36+00:00

__mkroute_input() uses fib_validate_source() to trigger an icmp redirect.
My understanding is that fib_validate_source() is used to know if the src
address and the gateway address are on the same link. For that,
fib_validate_source() returns 1 (same link) or 0 (not the same network).
__mkroute_input() is the only user of these positive values, all other
callers only look if the returned value is negative.

Since the below patch, fib_validate_source() didn't return anymore 1 when
both addresses are on the same network, because the route lookup returns
RT_SCOPE_LINK instead of RT_SCOPE_HOST. But this is, in fact, right.
Let's adapat the test to return 1 again when both addresses are on the same
link.

CC: stable@vger.kernel.org
Fixes: 747c14307214 ("ip: fix dflt addr selection for connected nexthop")
Reported-by: kernel test robot 
Reported-by: Heng Qi 
Signed-off-by: Nicolas Dichtel 
Reviewed-by: David Ahern 
Link: https://lore.kernel.org/r/20220829100121.3821-1-nicolas.dichtel@6wind.com
Signed-off-by: Jakub Kicinski

ipv4: remove unnecessary type castings

2022-04-30T14:12:58+00:00

remove unnecessary void* type castings.

Signed-off-by: Yu Zhe 
Signed-off-by: David S. Miller

net: Add l3mdev index to flow struct and avoid oif reset for port devices

2022-03-16T03:20:02+00:00

The fundamental premise of VRF and l3mdev core code is binding a socket
to a device (l3mdev or netdev with an L3 domain) to indicate L3 scope.
Legacy code resets flowi_oif to the l3mdev losing any original port
device binding. Ben (among others) has demonstrated use cases where the
original port device binding is important and needs to be retained.
This patch handles that by adding a new entry to the common flow struct
that can indicate the l3mdev index for later rule and table matching
avoiding the need to reset flowi_oif.

In addition to allowing more use cases that require port device binds,
this patch brings a few datapath simplications:

1. l3mdev_fib_rule_match is only called when walking fib rules and
   always after l3mdev_update_flow. That allows an optimization to bail
   early for non-VRF type uses cases when flowi_l3mdev is not set. Also,
   only that index needs to be checked for the FIB table id.

2. l3mdev_update_flow can be called with flowi_oif set to a l3mdev
   (e.g., VRF) device. By resetting flowi_oif only for this case the
   FLOWI_FLAG_SKIP_NH_OIF flag is not longer needed and can be removed,
   removing several checks in the datapath. The flowi_iif path can be
   simplified to only be called if the it is not loopback (loopback can
   not be assigned to an L3 domain) and the l3mdev index is not already
   set.

3. Avoid another device lookup in the output path when the fib lookup
   returns a reject failure.

Note: 2 functional tests for local traffic with reject fib rules are
updated to reflect the new direct failure at FIB lookup time for ping
rather than the failure on packet path. The current code fails like this:

    HINT: Fails since address on vrf device is out of device scope
    COMMAND: ip netns exec ns-A ping -c1 -w1 -I eth1 172.16.3.1
    ping: Warning: source address might be selected on device other than: eth1
    PING 172.16.3.1 (172.16.3.1) from 172.16.3.1 eth1: 56(84) bytes of data.

    --- 172.16.3.1 ping statistics ---
    1 packets transmitted, 0 received, 100% packet loss, time 0ms

where the test now directly fails:

    HINT: Fails since address on vrf device is out of device scope
    COMMAND: ip netns exec ns-A ping -c1 -w1 -I eth1 172.16.3.1
    ping: connect: No route to host

Signed-off-by: David Ahern 
Tested-by: Ben Greear 
Link: https://lore.kernel.org/r/20220314204551.16369-1-dsahern@kernel.org
Signed-off-by: Jakub Kicinski

ipv4: Invalidate neighbour for broadcast address upon address addition

2022-02-21T11:44:30+00:00

In case user space sends a packet destined to a broadcast address when a
matching broadcast route is not configured, the kernel will create a
unicast neighbour entry that will never be resolved [1].

When the broadcast route is configured, the unicast neighbour entry will
not be invalidated and continue to linger, resulting in packets being
dropped.

Solve this by invalidating unresolved neighbour entries for broadcast
addresses after routes for these addresses are internally configured by
the kernel. This allows the kernel to create a broadcast neighbour entry
following the next route lookup.

Another possible solution that is more generic but also more complex is
to have the ARP code register a listener to the FIB notification chain
and invalidate matching neighbour entries upon the addition of broadcast
routes.

It is also possible to wave off the issue as a user space problem, but
it seems a bit excessive to expect user space to be that intimately
familiar with the inner workings of the FIB/neighbour kernel code.

[1] https://lore.kernel.org/netdev/55a04a8f-56f3-f73c-2aea-2195923f09d1@huawei.com/

Reported-by: Wang Hai 
Signed-off-by: Ido Schimmel 
Tested-by: Wang Hai 
Signed-off-by: David S. Miller

Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net

2022-02-17T19:44:20+00:00

No conflicts.

Signed-off-by: Jakub Kicinski

ipv4: add description about martian source

2022-02-15T14:30:48+00:00

When multiple containers are running in the environment and multiple
macvlan network port are configured in each container, a lot of martian
source prints will appear after martian_log is enabled. they are almost
the same, and printed by net_warn_ratelimited. Each arp message will
trigger this print on each network port.

Such as:
IPv4: martian source 173.254.95.16 from 173.254.100.109,
on dev eth0
ll header: 00000000: ff ff ff ff ff ff 40 00 ad fe 64 6d
08 06        ......@...dm..
IPv4: martian source 173.254.95.16 from 173.254.100.109,
on dev eth1
ll header: 00000000: ff ff ff ff ff ff 40 00 ad fe 64 6d
08 06        ......@...dm..

There is no description of this kind of source in the RFC1812.

Signed-off-by: Zhang Yunkai 
Signed-off-by: David S. Miller

ipv4: add fib_net_exit_batch()

2022-02-09T04:41:33+00:00

cleanup_net() is competing with other rtnl users.

Instead of acquiring rtnl at each fib_net_exit() invocation,
add fib_net_exit_batch() so that rtnl is acquired once.

Signed-off-by: Eric Dumazet 
Reviewed-by: David Ahern 
Signed-off-by: Jakub Kicinski