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authorLinus Torvalds <torvalds@linux-foundation.org>2014-08-06 09:38:14 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2014-08-06 09:38:14 -0700
commitae045e2455429c418a418a3376301a9e5753a0a8 (patch)
treeb445bdeecd3f38aa0d0a29c9585cee49e4ccb0f1 /Documentation/networking/packet_mmap.txt
parentf4f142ed4ef835709c7e6d12eaca10d190bcebed (diff)
parentd247b6ab3ce6dd43665780865ec5fa145d9ab6bd (diff)
downloadop-kernel-dev-ae045e2455429c418a418a3376301a9e5753a0a8.zip
op-kernel-dev-ae045e2455429c418a418a3376301a9e5753a0a8.tar.gz
Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next
Pull networking updates from David Miller: "Highlights: 1) Steady transitioning of the BPF instructure to a generic spot so all kernel subsystems can make use of it, from Alexei Starovoitov. 2) SFC driver supports busy polling, from Alexandre Rames. 3) Take advantage of hash table in UDP multicast delivery, from David Held. 4) Lighten locking, in particular by getting rid of the LRU lists, in inet frag handling. From Florian Westphal. 5) Add support for various RFC6458 control messages in SCTP, from Geir Ola Vaagland. 6) Allow to filter bridge forwarding database dumps by device, from Jamal Hadi Salim. 7) virtio-net also now supports busy polling, from Jason Wang. 8) Some low level optimization tweaks in pktgen from Jesper Dangaard Brouer. 9) Add support for ipv6 address generation modes, so that userland can have some input into the process. From Jiri Pirko. 10) Consolidate common TCP connection request code in ipv4 and ipv6, from Octavian Purdila. 11) New ARP packet logger in netfilter, from Pablo Neira Ayuso. 12) Generic resizable RCU hash table, with intial users in netlink and nftables. From Thomas Graf. 13) Maintain a name assignment type so that userspace can see where a network device name came from (enumerated by kernel, assigned explicitly by userspace, etc.) From Tom Gundersen. 14) Automatic flow label generation on transmit in ipv6, from Tom Herbert. 15) New packet timestamping facilities from Willem de Bruijn, meant to assist in measuring latencies going into/out-of the packet scheduler, latency from TCP data transmission to ACK, etc" * git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next: (1536 commits) cxgb4 : Disable recursive mailbox commands when enabling vi net: reduce USB network driver config options. tg3: Modify tg3_tso_bug() to handle multiple TX rings amd-xgbe: Perform phy connect/disconnect at dev open/stop amd-xgbe: Use dma_set_mask_and_coherent to set DMA mask net: sun4i-emac: fix memory leak on bad packet sctp: fix possible seqlock seadlock in sctp_packet_transmit() Revert "net: phy: Set the driver when registering an MDIO bus device" cxgb4vf: Turn off SGE RX/TX Callback Timers and interrupts in PCI shutdown routine team: Simplify return path of team_newlink bridge: Update outdated comment on promiscuous mode net-timestamp: ACK timestamp for bytestreams net-timestamp: TCP timestamping net-timestamp: SCHED timestamp on entering packet scheduler net-timestamp: add key to disambiguate concurrent datagrams net-timestamp: move timestamp flags out of sk_flags net-timestamp: extend SCM_TIMESTAMPING ancillary data struct cxgb4i : Move stray CPL definitions to cxgb4 driver tcp: reduce spurious retransmits due to transient SACK reneging qlcnic: Initialize dcbnl_ops before register_netdev ...
Diffstat (limited to 'Documentation/networking/packet_mmap.txt')
-rw-r--r--Documentation/networking/packet_mmap.txt18
1 files changed, 6 insertions, 12 deletions
diff --git a/Documentation/networking/packet_mmap.txt b/Documentation/networking/packet_mmap.txt
index 38112d5..a6d7cb9 100644
--- a/Documentation/networking/packet_mmap.txt
+++ b/Documentation/networking/packet_mmap.txt
@@ -1008,14 +1008,9 @@ hardware timestamps to be used. Note: you may need to enable the generation
of hardware timestamps with SIOCSHWTSTAMP (see related information from
Documentation/networking/timestamping.txt).
-PACKET_TIMESTAMP accepts the same integer bit field as
-SO_TIMESTAMPING. However, only the SOF_TIMESTAMPING_SYS_HARDWARE
-and SOF_TIMESTAMPING_RAW_HARDWARE values are recognized by
-PACKET_TIMESTAMP. SOF_TIMESTAMPING_SYS_HARDWARE takes precedence over
-SOF_TIMESTAMPING_RAW_HARDWARE if both bits are set.
-
- int req = 0;
- req |= SOF_TIMESTAMPING_SYS_HARDWARE;
+PACKET_TIMESTAMP accepts the same integer bit field as SO_TIMESTAMPING:
+
+ int req = SOF_TIMESTAMPING_RAW_HARDWARE;
setsockopt(fd, SOL_PACKET, PACKET_TIMESTAMP, (void *) &req, sizeof(req))
For the mmap(2)ed ring buffers, such timestamps are stored in the
@@ -1023,14 +1018,13 @@ tpacket{,2,3}_hdr structure's tp_sec and tp_{n,u}sec members. To determine
what kind of timestamp has been reported, the tp_status field is binary |'ed
with the following possible bits ...
- TP_STATUS_TS_SYS_HARDWARE
TP_STATUS_TS_RAW_HARDWARE
TP_STATUS_TS_SOFTWARE
... that are equivalent to its SOF_TIMESTAMPING_* counterparts. For the
-RX_RING, if none of those 3 are set (i.e. PACKET_TIMESTAMP is not set),
-then this means that a software fallback was invoked *within* PF_PACKET's
-processing code (less precise).
+RX_RING, if neither is set (i.e. PACKET_TIMESTAMP is not set), then a
+software fallback was invoked *within* PF_PACKET's processing code (less
+precise).
Getting timestamps for the TX_RING works as follows: i) fill the ring frames,
ii) call sendto() e.g. in blocking mode, iii) wait for status of relevant
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