From: Dongseok Yi <dseok.yi@samsung.com>
To: "David S. Miller" <davem@davemloft.net>
Cc: namkyu78.kim@samsung.com, Dongseok Yi <dseok.yi@samsung.com>,
Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>,
Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>,
Jakub Kicinski <kuba@kernel.org>,
Willem de Bruijn <willemb@google.com>,
Steffen Klassert <steffen.klassert@secunet.com>,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [RFC PATCH net] udp: check sk for UDP GRO fraglist
Date: Fri, 8 Jan 2021 21:52:28 +0900 [thread overview]
Message-ID: <1610110348-119768-1-git-send-email-dseok.yi@samsung.com> (raw)
In-Reply-To: CGME20210108130414epcas2p3217d7b6ac8a8094c5b3b6c5e52480134@epcas2p3.samsung.com
It is a workaround patch.
UDP/IP header of UDP GROed frag_skbs are not updated even after NAT
forwarding. Only the header of head_skb from ip_finish_output_gso ->
skb_gso_segment is updated but following frag_skbs are not updated.
A call path skb_mac_gso_segment -> inet_gso_segment ->
udp4_ufo_fragment -> __udp_gso_segment -> __udp_gso_segment_list
does not try to update any UDP/IP header of the segment list.
It might make sense because each skb of frag_skbs is converted to a
list of regular packets. Header update with checksum calculation may
be not needed for UDP GROed frag_skbs.
But UDP GRO frag_list is started from udp_gro_receive, we don't know
whether the skb will be NAT forwarded at that time. For workaround,
try to get sock always when call udp4_gro_receive -> udp_gro_receive
to check if the skb is for local.
I'm still not sure if UDP GRO frag_list is really designed for local
session only. Can kernel support NAT forward for UDP GRO frag_list?
What am I missing?
Fixes: 9fd1ff5d2ac7 (udp: Support UDP fraglist GRO/GSO.)
Signed-off-by: Dongseok Yi <dseok.yi@samsung.com>
---
net/ipv4/udp_offload.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)
diff --git a/net/ipv4/udp_offload.c b/net/ipv4/udp_offload.c
index ff39e94..d476216 100644
--- a/net/ipv4/udp_offload.c
+++ b/net/ipv4/udp_offload.c
@@ -457,7 +457,7 @@ struct sk_buff *udp_gro_receive(struct list_head *head, struct sk_buff *skb,
int flush = 1;
NAPI_GRO_CB(skb)->is_flist = 0;
- if (skb->dev->features & NETIF_F_GRO_FRAGLIST)
+ if (sk && (skb->dev->features & NETIF_F_GRO_FRAGLIST))
NAPI_GRO_CB(skb)->is_flist = sk ? !udp_sk(sk)->gro_enabled: 1;
if ((sk && udp_sk(sk)->gro_enabled) || NAPI_GRO_CB(skb)->is_flist) {
@@ -537,8 +537,7 @@ struct sk_buff *udp4_gro_receive(struct list_head *head, struct sk_buff *skb)
NAPI_GRO_CB(skb)->is_ipv6 = 0;
rcu_read_lock();
- if (static_branch_unlikely(&udp_encap_needed_key))
- sk = udp4_gro_lookup_skb(skb, uh->source, uh->dest);
+ sk = udp4_gro_lookup_skb(skb, uh->source, uh->dest);
pp = udp_gro_receive(head, skb, uh, sk);
rcu_read_unlock();
--
2.7.4
next parent reply other threads:[~2021-01-08 13:05 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CGME20210108130414epcas2p3217d7b6ac8a8094c5b3b6c5e52480134@epcas2p3.samsung.com>
2021-01-08 12:52 ` Dongseok Yi [this message]
2021-01-08 13:35 ` [RFC PATCH net] udp: check sk for UDP GRO fraglist Steffen Klassert
2021-01-11 2:02 ` Dongseok Yi
2021-01-11 8:43 ` Steffen Klassert
2021-01-11 12:09 Alexander Lobakin
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