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| author | Guillaume Nault <gnault@redhat.com> | 2025-03-29 01:33:44 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2025-04-10 14:31:00 +0200 |
| commit | b860c7878fbf006feab1696054b13d6420a3a7cc (patch) | |
| tree | 200ffb644774c02c0f401097526a4692e79b203a | |
| parent | 48c2ee183557cb2f98d06456ed47ca96324d2559 (diff) | |
| download | linux-b860c7878fbf006feab1696054b13d6420a3a7cc.tar.gz linux-b860c7878fbf006feab1696054b13d6420a3a7cc.tar.bz2 linux-b860c7878fbf006feab1696054b13d6420a3a7cc.zip | |
tunnels: Accept PACKET_HOST in skb_tunnel_check_pmtu().
[ Upstream commit 8930424777e43257f5bf6f0f0f53defd0d30415c ]
Because skb_tunnel_check_pmtu() doesn't handle PACKET_HOST packets,
commit 30a92c9e3d6b ("openvswitch: Set the skbuff pkt_type for proper
pmtud support.") forced skb->pkt_type to PACKET_OUTGOING for
openvswitch packets that are sent using the OVS_ACTION_ATTR_OUTPUT
action. This allowed such packets to invoke the
iptunnel_pmtud_check_icmp() or iptunnel_pmtud_check_icmpv6() helpers
and thus trigger PMTU update on the input device.
However, this also broke other parts of PMTU discovery. Since these
packets don't have the PACKET_HOST type anymore, they won't trigger the
sending of ICMP Fragmentation Needed or Packet Too Big messages to
remote hosts when oversized (see the skb_in->pkt_type condition in
__icmp_send() for example).
These two skb->pkt_type checks are therefore incompatible as one
requires skb->pkt_type to be PACKET_HOST, while the other requires it
to be anything but PACKET_HOST.
It makes sense to not trigger ICMP messages for non-PACKET_HOST packets
as these messages should be generated only for incoming l2-unicast
packets. However there doesn't seem to be any reason for
skb_tunnel_check_pmtu() to ignore PACKET_HOST packets.
Allow both cases to work by allowing skb_tunnel_check_pmtu() to work on
PACKET_HOST packets and not overriding skb->pkt_type in openvswitch
anymore.
Fixes: 30a92c9e3d6b ("openvswitch: Set the skbuff pkt_type for proper pmtud support.")
Fixes: 4cb47a8644cc ("tunnels: PMTU discovery support for directly bridged IP packets")
Signed-off-by: Guillaume Nault <gnault@redhat.com>
Reviewed-by: Stefano Brivio <sbrivio@redhat.com>
Reviewed-by: Aaron Conole <aconole@redhat.com>
Tested-by: Aaron Conole <aconole@redhat.com>
Link: https://patch.msgid.link/eac941652b86fddf8909df9b3bf0d97bc9444793.1743208264.git.gnault@redhat.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
| -rw-r--r-- | net/ipv4/ip_tunnel_core.c | 2 | ||||
| -rw-r--r-- | net/openvswitch/actions.c | 6 |
2 files changed, 1 insertions, 7 deletions
diff --git a/net/ipv4/ip_tunnel_core.c b/net/ipv4/ip_tunnel_core.c index ba1388ba6c6e..dad9d7db5bf6 100644 --- a/net/ipv4/ip_tunnel_core.c +++ b/net/ipv4/ip_tunnel_core.c @@ -415,7 +415,7 @@ int skb_tunnel_check_pmtu(struct sk_buff *skb, struct dst_entry *encap_dst, skb_dst_update_pmtu_no_confirm(skb, mtu); - if (!reply || skb->pkt_type == PACKET_HOST) + if (!reply) return 0; if (skb->protocol == htons(ETH_P_IP)) diff --git a/net/openvswitch/actions.c b/net/openvswitch/actions.c index 4095456f413d..80fee9d118ee 100644 --- a/net/openvswitch/actions.c +++ b/net/openvswitch/actions.c @@ -923,12 +923,6 @@ static void do_output(struct datapath *dp, struct sk_buff *skb, int out_port, pskb_trim(skb, ovs_mac_header_len(key)); } - /* Need to set the pkt_type to involve the routing layer. The - * packet movement through the OVS datapath doesn't generally - * use routing, but this is needed for tunnel cases. - */ - skb->pkt_type = PACKET_OUTGOING; - if (likely(!mru || (skb->len <= mru + vport->dev->hard_header_len))) { ovs_vport_send(vport, skb, ovs_key_mac_proto(key)); |