[ Upstream commit 30a92c9e3d6b073932762bef2ac66f4ee784c657 ]
Open vSwitch is originally intended to switch at layer 2, only dealing with
Ethernet frames. With the introduction of l3 tunnels support, it crossed
into the realm of needing to care a bit about some routing details when
making forwarding decisions. If an oversized packet would need to be
fragmented during this forwarding decision, there is a chance for pmtu
to get involved and generate a routing exception. This is gated by the
skbuff->pkt_type field.
When a flow is already loaded into the openvswitch module this field is
set up and transitioned properly as a packet moves from one port to
another. In the case that a packet execute is invoked after a flow is
newly installed this field is not properly initialized. This causes the
pmtud mechanism to omit sending the required exception messages across
the tunnel boundary and a second attempt needs to be made to make sure
that the routing exception is properly setup. To fix this, we set the
outgoing packet's pkt_type to PACKET_OUTGOING, since it can only get
to the openvswitch module via a port device or packet command.
Even for bridge ports as users, the pkt_type needs to be reset when
doing the transmit as the packet is truly outgoing and routing needs
to get involved post packet transformations, in the case of
VXLAN/GENEVE/udp-tunnel packets. In general, the pkt_type on output
gets ignored, since we go straight to the driver, but in the case of
tunnel ports they go through IP routing layer.
This issue is periodically encountered in complex setups, such as large
openshift deployments, where multiple sets of tunnel traversal occurs.
A way to recreate this is with the ovn-heater project that can setup
a networking environment which mimics such large deployments. We need
larger environments for this because we need to ensure that flow
misses occur. In these environment, without this patch, we can see:
./ovn_cluster.sh start
podman exec ovn-chassis-1 ip r a 170.168.0.5/32 dev eth1 mtu 1200
podman exec ovn-chassis-1 ip netns exec sw01p1 ip r flush cache
podman exec ovn-chassis-1 ip netns exec sw01p1 \
ping 21.0.0.3 -M do -s 1300 -c2
PING 21.0.0.3 (21.0.0.3) 1300(1328) bytes of data.
From 21.0.0.3 icmp_seq=2 Frag needed and DF set (mtu = 1142)
--- 21.0.0.3 ping statistics ---
...
Using tcpdump, we can also see the expected ICMP FRAG_NEEDED message is not
sent into the server.
With this patch, setting the pkt_type, we see the following:
podman exec ovn-chassis-1 ip netns exec sw01p1 \
ping 21.0.0.3 -M do -s 1300 -c2
PING 21.0.0.3 (21.0.0.3) 1300(1328) bytes of data.
From 21.0.0.3 icmp_seq=1 Frag needed and DF set (mtu = 1222)
ping: local error: message too long, mtu=1222
--- 21.0.0.3 ping statistics ---
...
In this case, the first ping request receives the FRAG_NEEDED message and
a local routing exception is created.
Tested-by: Jaime Caamano <jcaamano@redhat.com>
Reported-at: https://issues.redhat.com/browse/FDP-164
Fixes: 58264848a5a7 ("openvswitch: Add vxlan tunneling support.")
Signed-off-by: Aaron Conole <aconole@redhat.com>
Acked-by: Eelco Chaudron <echaudro@redhat.com>
Link: https://lore.kernel.org/r/20240516200941.16152-1-aconole@redhat.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 7c988176b6c16c516474f6fceebe0f055af5eb56 ]
OVS_PACKET_CMD_EXECUTE has 3 main attributes:
- OVS_PACKET_ATTR_KEY - Packet metadata in a netlink format.
- OVS_PACKET_ATTR_PACKET - Binary packet content.
- OVS_PACKET_ATTR_ACTIONS - Actions to execute on the packet.
OVS_PACKET_ATTR_KEY is parsed first to populate sw_flow_key structure
with the metadata like conntrack state, input port, recirculation id,
etc. Then the packet itself gets parsed to populate the rest of the
keys from the packet headers.
Whenever the packet parsing code starts parsing the ICMPv6 header, it
first zeroes out fields in the key corresponding to Neighbor Discovery
information even if it is not an ND packet.
It is an 'ipv6.nd' field. However, the 'ipv6' is a union that shares
the space between 'nd' and 'ct_orig' that holds the original tuple
conntrack metadata parsed from the OVS_PACKET_ATTR_KEY.
ND packets should not normally have conntrack state, so it's fine to
share the space, but normal ICMPv6 Echo packets or maybe other types of
ICMPv6 can have the state attached and it should not be overwritten.
The issue results in all but the last 4 bytes of the destination
address being wiped from the original conntrack tuple leading to
incorrect packet matching and potentially executing wrong actions
in case this packet recirculates within the datapath or goes back
to userspace.
ND fields should not be accessed in non-ND packets, so not clearing
them should be fine. Executing memset() only for actual ND packets to
avoid the issue.
Initializing the whole thing before parsing is needed because ND packet
may not contain all the options.
The issue only affects the OVS_PACKET_CMD_EXECUTE path and doesn't
affect packets entering OVS datapath from network interfaces, because
in this case CT metadata is populated from skb after the packet is
already parsed.
Fixes: 9dd7f8907c37 ("openvswitch: Add original direction conntrack tuple to sw_flow_key.")
Reported-by: Antonin Bas <antonin.bas@broadcom.com>
Closes: https://github.com/openvswitch/ovs-issues/issues/327
Signed-off-by: Ilya Maximets <i.maximets@ovn.org>
Acked-by: Aaron Conole <aconole@redhat.com>
Acked-by: Eelco Chaudron <echaudro@redhat.com>
Link: https://lore.kernel.org/r/20240509094228.1035477-1-i.maximets@ovn.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 5ea7b72d4fac2fdbc0425cd8f2ea33abe95235b2 ]
Since kfree_rcu, which is called in the hlist_for_each_entry_rcu traversal
of ovs_ct_limit_exit, is not part of the RCU read critical section, it
is possible that the RCU grace period will pass during the traversal and
the key will be free.
To prevent this, it should be changed to hlist_for_each_entry_safe.
Fixes: 11efd5cb04a1 ("openvswitch: Support conntrack zone limit")
Signed-off-by: Hyunwoo Kim <v4bel@theori.io>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Aaron Conole <aconole@redhat.com>
Link: https://lore.kernel.org/r/ZiYvzQN/Ry5oeFQW@v4bel-B760M-AORUS-ELITE-AX
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 4539f91f2a801c0c028c252bffae56030cfb2cae ]
On startup, ovs-vswitchd probes different datapath features including
support for timeout policies. While probing, it tries to execute
certain operations with OVS_PACKET_ATTR_PROBE or OVS_FLOW_ATTR_PROBE
attributes set. These attributes tell the openvswitch module to not
log any errors when they occur as it is expected that some of the
probes will fail.
For some reason, setting the timeout policy ignores the PROBE attribute
and logs a failure anyway. This is causing the following kernel log
on each re-start of ovs-vswitchd:
kernel: Failed to associated timeout policy `ovs_test_tp'
Fix that by using the same logging macro that all other messages are
using. The message will still be printed at info level when needed
and will be rate limited, but with a net rate limiter instead of
generic printk one.
The nf_ct_set_timeout() itself will still print some info messages,
but at least this change makes logging in openvswitch module more
consistent.
Fixes: 06bd2bdf19d2 ("openvswitch: Add timeout support to ct action")
Signed-off-by: Ilya Maximets <i.maximets@ovn.org>
Acked-by: Eelco Chaudron <echaudro@redhat.com>
Link: https://lore.kernel.org/r/20240403203803.2137962-1-i.maximets@ovn.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 6e2f90d31fe09f2b852de25125ca875aabd81367 ]
The ovs module allows for some actions to recursively contain an action
list for complex scenarios, such as sampling, checking lengths, etc.
When these actions are copied into the internal flow table, they are
evaluated to validate that such actions make sense, and these calls
happen recursively.
The ovs-vswitchd userspace won't emit more than 16 recursion levels
deep. However, the module has no such limit and will happily accept
limits larger than 16 levels nested. Prevent this by tracking the
number of recursions happening and manually limiting it to 16 levels
nested.
The initial implementation of the sample action would track this depth
and prevent more than 3 levels of recursion, but this was removed to
support the clone use case, rather than limited at the current userspace
limit.
Fixes: 798c166173ff ("openvswitch: Optimize sample action for the clone use cases")
Signed-off-by: Aaron Conole <aconole@redhat.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://lore.kernel.org/r/20240207132416.1488485-2-aconole@redhat.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
