mirror of
https://github.com/torvalds/linux.git
synced 2026-07-30 11:11:26 +02:00
Linux kernel source tree
27942a1520
A latter patch will set the skb->mono_delivery_time to flag the skb->tstamp is used as the mono delivery_time (EDT) instead of the (rcv) timestamp. skb_clear_tstamp() will then keep this delivery_time during forwarding. This patch is to make the network tapping (with af_packet) to handle the delivery_time stored in skb->tstamp. Regardless of tapping at the ingress or egress, the tapped skb is received by the af_packet socket, so it is ingress to the af_packet socket and it expects the (rcv) timestamp. When tapping at egress, dev_queue_xmit_nit() is used. It has already expected skb->tstamp may have delivery_time, so it does skb_clone()+net_timestamp_set() to ensure the cloned skb has the (rcv) timestamp before passing to the af_packet sk. This patch only adds to clear the skb->mono_delivery_time bit in net_timestamp_set(). When tapping at ingress, it currently expects the skb->tstamp is either 0 or the (rcv) timestamp. Meaning, the tapping at ingress path has already expected the skb->tstamp could be 0 and it will get the (rcv) timestamp by ktime_get_real() when needed. There are two cases for tapping at ingress: One case is af_packet queues the skb to its sk_receive_queue. The skb is either not shared or new clone created. The newly added skb_clear_delivery_time() is called to clear the delivery_time (if any) and set the (rcv) timestamp if needed before the skb is queued to the sk_receive_queue. Another case, the ingress skb is directly copied to the rx_ring and tpacket_get_timestamp() is used to get the (rcv) timestamp. The newly added skb_tstamp() is used in tpacket_get_timestamp() to check the skb->mono_delivery_time bit before returning skb->tstamp. As mentioned earlier, the tapping@ingress has already expected the skb may not have the (rcv) timestamp (because no sk has asked for it) and has handled this case by directly calling ktime_get_real(). Signed-off-by: Martin KaFai Lau <kafai@fb.com> Signed-off-by: David S. Miller <davem@davemloft.net> |
||
|---|---|---|
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.