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: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/net/inet_frag.h b/include/net/inet_frag.h
index 63540be..911ad93 100644 (file)
--- 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 3410968..63948f6 100644 (file)
--- 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 fad803d..fb15356 100644 (file)
--- 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);