diff mbox series

[v6,net-next,06/13] net: ip: Handle delivery_time in ip defrag

Message ID 20220302195557.3481523-1-kafai@fb.com (mailing list archive)
State Accepted
Commit 8672406eb5d77333ca14e9612e3166704b367c40
Delegated to: Netdev Maintainers
Headers show
Series Preserve mono delivery time (EDT) in skb->tstamp | expand

Checks

Context Check Description
netdev/tree_selection success Clearly marked for net-next
netdev/fixes_present success Fixes tag not required for -next series
netdev/subject_prefix success Link
netdev/cover_letter success Series has a cover letter
netdev/patch_count success Link
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 5143 this patch: 5143
netdev/cc_maintainers warning 6 maintainers not CCed: kpsingh@kernel.org john.fastabend@gmail.com songliubraving@fb.com dsahern@kernel.org yhs@fb.com yoshfuji@linux-ipv6.org
netdev/build_clang success Errors and warnings before: 858 this patch: 858
netdev/module_param success Was 0 now: 0
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 5295 this patch: 5295
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 28 lines checked
netdev/kdoc success Errors and warnings before: 2 this patch: 2
netdev/source_inline success Was 0 now: 0

Commit Message

Martin KaFai Lau March 2, 2022, 7:55 p.m. UTC
A latter patch will postpone the delivery_time clearing until the stack
knows the skb is being delivered locally.  That will allow other kernel
forwarding path (e.g. ip[6]_forward) to keep the delivery_time also.

An earlier attempt was to do skb_clear_delivery_time() in
ip_local_deliver() and ip6_input().  The discussion [0] requested
to move it one step later into ip_local_deliver_finish()
and ip6_input_finish() so that the delivery_time can be kept
for the ip_vs forwarding path also.

To do that, this patch also needs to take care of the (rcv) timestamp
usecase in ip_is_fragment().  It needs to expect delivery_time in
the skb->tstamp, so it needs to save the mono_delivery_time bit in
inet_frag_queue such that the delivery_time (if any) can be restored
in the final defragmented skb.

[Note that it will only happen when the locally generated skb is looping
 from egress to ingress over a virtual interface (e.g. veth, loopback...),
 skb->tstamp may have the delivery time before it is known that it will
 be delivered locally and received by another sk.]

[0]: https://lore.kernel.org/netdev/ca728d81-80e8-3767-d5e-d44f6ad96e43@ssi.bg/

Signed-off-by: Martin KaFai Lau <kafai@fb.com>
---
 include/net/inet_frag.h  | 2 ++
 net/ipv4/inet_fragment.c | 1 +
 net/ipv4/ip_fragment.c   | 1 +
 3 files changed, 4 insertions(+)
diff mbox series

Patch

diff --git a/include/net/inet_frag.h b/include/net/inet_frag.h
index 63540be0fc34..911ad930867d 100644
--- a/include/net/inet_frag.h
+++ b/include/net/inet_frag.h
@@ -70,6 +70,7 @@  struct frag_v6_compare_key {
  * @stamp: timestamp of the last received fragment
  * @len: total length of the original datagram
  * @meat: length of received fragments so far
+ * @mono_delivery_time: stamp has a mono delivery time (EDT)
  * @flags: fragment queue flags
  * @max_size: maximum received fragment size
  * @fqdir: pointer to struct fqdir
@@ -90,6 +91,7 @@  struct inet_frag_queue {
 	ktime_t			stamp;
 	int			len;
 	int			meat;
+	u8			mono_delivery_time;
 	__u8			flags;
 	u16			max_size;
 	struct fqdir		*fqdir;
diff --git a/net/ipv4/inet_fragment.c b/net/ipv4/inet_fragment.c
index 341096807100..63948f6aeca0 100644
--- a/net/ipv4/inet_fragment.c
+++ b/net/ipv4/inet_fragment.c
@@ -572,6 +572,7 @@  void inet_frag_reasm_finish(struct inet_frag_queue *q, struct sk_buff *head,
 	skb_mark_not_on_list(head);
 	head->prev = NULL;
 	head->tstamp = q->stamp;
+	head->mono_delivery_time = q->mono_delivery_time;
 }
 EXPORT_SYMBOL(inet_frag_reasm_finish);
 
diff --git a/net/ipv4/ip_fragment.c b/net/ipv4/ip_fragment.c
index fad803d2d711..fb153569889e 100644
--- a/net/ipv4/ip_fragment.c
+++ b/net/ipv4/ip_fragment.c
@@ -349,6 +349,7 @@  static int ip_frag_queue(struct ipq *qp, struct sk_buff *skb)
 		qp->iif = dev->ifindex;
 
 	qp->q.stamp = skb->tstamp;
+	qp->q.mono_delivery_time = skb->mono_delivery_time;
 	qp->q.meat += skb->len;
 	qp->ecn |= ecn;
 	add_frag_mem_limit(qp->q.fqdir, skb->truesize);