Commit 8672406e authored by Martin KaFai Lau's avatar Martin KaFai Lau Committed by David S. Miller
Browse files

net: ip: Handle delivery_time in ip defrag 

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: default avatarMartin KaFai Lau <kafai@fb.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent d98d58a0

include/net/inet_frag.h

+2 −0
Original line number Diff line number Diff line
@@ -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;

net/ipv4/inet_fragment.c

+1 −0
Original line number Diff line number Diff line
@@ -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);

net/ipv4/ip_fragment.c

+1 −0
Original line number Diff line number Diff line
@@ -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);