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authorLinus Torvalds <torvalds@linux-foundation.org>2014-12-11 14:27:06 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2014-12-11 14:27:06 -0800
commit70e71ca0af244f48a5dcf56dc435243792e3a495 (patch)
treef7d9c4c4d9a857a00043e9bf6aa2d6f533a34778 /Documentation/networking/timestamping.txt
parentbae41e45b7400496b9bf0c70c6004419d9987819 (diff)
parent00c83b01d58068dfeb2e1351cca6fccf2a83fa8f (diff)
Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next
Pull networking updates from David Miller: 1) New offloading infrastructure and example 'rocker' driver for offloading of switching and routing to hardware. This work was done by a large group of dedicated individuals, not limited to: Scott Feldman, Jiri Pirko, Thomas Graf, John Fastabend, Jamal Hadi Salim, Andy Gospodarek, Florian Fainelli, Roopa Prabhu 2) Start making the networking operate on IOV iterators instead of modifying iov objects in-situ during transfers. Thanks to Al Viro and Herbert Xu. 3) A set of new netlink interfaces for the TIPC stack, from Richard Alpe. 4) Remove unnecessary looping during ipv6 routing lookups, from Martin KaFai Lau. 5) Add PAUSE frame generation support to gianfar driver, from Matei Pavaluca. 6) Allow for larger reordering levels in TCP, which are easily achievable in the real world right now, from Eric Dumazet. 7) Add a variable of napi_schedule that doesn't need to disable cpu interrupts, from Eric Dumazet. 8) Use a doubly linked list to optimize neigh_parms_release(), from Nicolas Dichtel. 9) Various enhancements to the kernel BPF verifier, and allow eBPF programs to actually be attached to sockets. From Alexei Starovoitov. 10) Support TSO/LSO in sunvnet driver, from David L Stevens. 11) Allow controlling ECN usage via routing metrics, from Florian Westphal. 12) Remote checksum offload, from Tom Herbert. 13) Add split-header receive, BQL, and xmit_more support to amd-xgbe driver, from Thomas Lendacky. 14) Add MPLS support to openvswitch, from Simon Horman. 15) Support wildcard tunnel endpoints in ipv6 tunnels, from Steffen Klassert. 16) Do gro flushes on a per-device basis using a timer, from Eric Dumazet. This tries to resolve the conflicting goals between the desired handling of bulk vs. RPC-like traffic. 17) Allow userspace to ask for the CPU upon what a packet was received/steered, via SO_INCOMING_CPU. From Eric Dumazet. 18) Limit GSO packets to half the current congestion window, from Eric Dumazet. 19) Add a generic helper so that all drivers set their RSS keys in a consistent way, from Eric Dumazet. 20) Add xmit_more support to enic driver, from Govindarajulu Varadarajan. 21) Add VLAN packet scheduler action, from Jiri Pirko. 22) Support configurable RSS hash functions via ethtool, from Eyal Perry. * git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next: (1820 commits) Fix race condition between vxlan_sock_add and vxlan_sock_release net/macb: fix compilation warning for print_hex_dump() called with skb->mac_header net/mlx4: Add support for A0 steering net/mlx4: Refactor QUERY_PORT net/mlx4_core: Add explicit error message when rule doesn't meet configuration net/mlx4: Add A0 hybrid steering net/mlx4: Add mlx4_bitmap zone allocator net/mlx4: Add a check if there are too many reserved QPs net/mlx4: Change QP allocation scheme net/mlx4_core: Use tasklet for user-space CQ completion events net/mlx4_core: Mask out host side virtualization features for guests net/mlx4_en: Set csum level for encapsulated packets be2net: Export tunnel offloads only when a VxLAN tunnel is created gianfar: Fix dma check map error when DMA_API_DEBUG is enabled cxgb4/csiostor: Don't use MASTER_MUST for fw_hello call net: fec: only enable mdio interrupt before phy device link up net: fec: clear all interrupt events to support i.MX6SX net: fec: reset fep link status in suspend function net: sock: fix access via invalid file descriptor net: introduce helper macro for_each_cmsghdr ...
Diffstat (limited to 'Documentation/networking/timestamping.txt')
-rw-r--r--Documentation/networking/timestamping.txt33
1 files changed, 25 insertions, 8 deletions
diff --git a/Documentation/networking/timestamping.txt b/Documentation/networking/timestamping.txt
index 1d6d02d6ba52..a5c784c89312 100644
--- a/Documentation/networking/timestamping.txt
+++ b/Documentation/networking/timestamping.txt
@@ -122,7 +122,7 @@ SOF_TIMESTAMPING_RAW_HARDWARE:
1.3.3 Timestamp Options
-The interface supports one option
+The interface supports the options
SOF_TIMESTAMPING_OPT_ID:
@@ -130,19 +130,36 @@ SOF_TIMESTAMPING_OPT_ID:
have multiple concurrent timestamping requests outstanding. Packets
can be reordered in the transmit path, for instance in the packet
scheduler. In that case timestamps will be queued onto the error
- queue out of order from the original send() calls. This option
- embeds a counter that is incremented at send() time, to order
- timestamps within a flow.
+ queue out of order from the original send() calls. It is not always
+ possible to uniquely match timestamps to the original send() calls
+ based on timestamp order or payload inspection alone, then.
+
+ This option associates each packet at send() with a unique
+ identifier and returns that along with the timestamp. The identifier
+ is derived from a per-socket u32 counter (that wraps). For datagram
+ sockets, the counter increments with each sent packet. For stream
+ sockets, it increments with every byte.
+
+ The counter starts at zero. It is initialized the first time that
+ the socket option is enabled. It is reset each time the option is
+ enabled after having been disabled. Resetting the counter does not
+ change the identifiers of existing packets in the system.
This option is implemented only for transmit timestamps. There, the
timestamp is always looped along with a struct sock_extended_err.
The option modifies field ee_data to pass an id that is unique
among all possibly concurrently outstanding timestamp requests for
- that socket. In practice, it is a monotonically increasing u32
- (that wraps).
+ that socket.
+
+
+SOF_TIMESTAMPING_OPT_CMSG:
- In datagram sockets, the counter increments on each send call. In
- stream sockets, it increments with every byte.
+ Support recv() cmsg for all timestamped packets. Control messages
+ are already supported unconditionally on all packets with receive
+ timestamps and on IPv6 packets with transmit timestamp. This option
+ extends them to IPv4 packets with transmit timestamp. One use case
+ is to correlate packets with their egress device, by enabling socket
+ option IP_PKTINFO simultaneously.
1.4 Bytestream Timestamps