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authorLinus Torvalds <torvalds@linux-foundation.org>2021-01-05 12:38:56 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2021-01-05 12:38:56 -0800
commitaa35e45cd42aa249562c65e440c8d69fb84945d9 (patch)
tree02b2c6f445a74e8d4b1f634156424169601ac866 /Documentation/networking/packet_mmap.rst
parent6207214a70bfaec7b41f39502353fd3ca89df68c (diff)
parenta8f33c038f4e50b0f47448cb6c6ca184c4f717ef (diff)
Merge tag 'net-5.11-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
Pull networking fixes from Jakub Kicinski: "Networking fixes, including fixes from netfilter, wireless and bpf trees. Current release - regressions: - mt76: fix NULL pointer dereference in mt76u_status_worker and mt76s_process_tx_queue - net: ipa: fix interconnect enable bug Current release - always broken: - netfilter: fixes possible oops in mtype_resize in ipset - ath11k: fix number of coding issues found by static analysis tools and spurious error messages Previous releases - regressions: - e1000e: re-enable s0ix power saving flows for systems with the Intel i219-LM Ethernet controllers to fix power use regression - virtio_net: fix recursive call to cpus_read_lock() to avoid a deadlock - ipv4: ignore ECN bits for fib lookups in fib_compute_spec_dst() - sysfs: take the rtnl lock around XPS configuration - xsk: fix memory leak for failed bind and rollback reservation at NETDEV_TX_BUSY - r8169: work around power-saving bug on some chip versions Previous releases - always broken: - dcb: validate netlink message in DCB handler - tun: fix return value when the number of iovs exceeds MAX_SKB_FRAGS to prevent unnecessary retries - vhost_net: fix ubuf refcount when sendmsg fails - bpf: save correct stopping point in file seq iteration - ncsi: use real net-device for response handler - neighbor: fix div by zero caused by a data race (TOCTOU) - bareudp: fix use of incorrect min_headroom size and a false positive lockdep splat from the TX lock - mvpp2: - clear force link UP during port init procedure in case bootloader had set it - add TCAM entry to drop flow control pause frames - fix PPPoE with ipv6 packet parsing - fix GoP Networking Complex Control config of port 3 - fix pkt coalescing IRQ-threshold configuration - xsk: fix race in SKB mode transmit with shared cq - ionic: account for vlan tag len in rx buffer len - stmmac: ignore the second clock input, current clock framework does not handle exclusive clock use well, other drivers may reconfigure the second clock Misc: - ppp: change PPPIOCUNBRIDGECHAN ioctl request number to follow existing scheme" * tag 'net-5.11-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (99 commits) net: dsa: lantiq_gswip: Fix GSWIP_MII_CFG(p) register access net: dsa: lantiq_gswip: Enable GSWIP_MII_CFG_EN also for internal PHYs net: lapb: Decrease the refcount of "struct lapb_cb" in lapb_device_event r8169: work around power-saving bug on some chip versions net: usb: qmi_wwan: add Quectel EM160R-GL selftests: mlxsw: Set headroom size of correct port net: macb: Correct usage of MACB_CAPS_CLK_HW_CHG flag ibmvnic: fix: NULL pointer dereference. docs: networking: packet_mmap: fix old config reference docs: networking: packet_mmap: fix formatting for C macros vhost_net: fix ubuf refcount incorrectly when sendmsg fails bareudp: Fix use of incorrect min_headroom size bareudp: set NETIF_F_LLTX flag net: hdlc_ppp: Fix issues when mod_timer is called while timer is running atlantic: remove architecture depends erspan: fix version 1 check in gre_parse_header() net: hns: fix return value check in __lb_other_process() net: sched: prevent invalid Scell_log shift count net: neighbor: fix a crash caused by mod zero ipv4: Ignore ECN bits for fib lookups in fib_compute_spec_dst() ...
Diffstat (limited to 'Documentation/networking/packet_mmap.rst')
-rw-r--r--Documentation/networking/packet_mmap.rst11
1 files changed, 5 insertions, 6 deletions
diff --git a/Documentation/networking/packet_mmap.rst b/Documentation/networking/packet_mmap.rst
index 6c009ceb1183..500ef60b1b82 100644
--- a/Documentation/networking/packet_mmap.rst
+++ b/Documentation/networking/packet_mmap.rst
@@ -8,7 +8,7 @@ Abstract
========
This file documents the mmap() facility available with the PACKET
-socket interface on 2.4/2.6/3.x kernels. This type of sockets is used for
+socket interface. This type of sockets is used for
i) capture network traffic with utilities like tcpdump,
ii) transmit network traffic, or any other that needs raw
@@ -25,12 +25,12 @@ Please send your comments to
Why use PACKET_MMAP
===================
-In Linux 2.4/2.6/3.x if PACKET_MMAP is not enabled, the capture process is very
+Non PACKET_MMAP capture process (plain AF_PACKET) is very
inefficient. It uses very limited buffers and requires one system call to
capture each packet, it requires two if you want to get packet's timestamp
(like libpcap always does).
-In the other hand PACKET_MMAP is very efficient. PACKET_MMAP provides a size
+On the other hand PACKET_MMAP is very efficient. PACKET_MMAP provides a size
configurable circular buffer mapped in user space that can be used to either
send or receive packets. This way reading packets just needs to wait for them,
most of the time there is no need to issue a single system call. Concerning
@@ -252,8 +252,7 @@ PACKET_MMAP setting constraints
In kernel versions prior to 2.4.26 (for the 2.4 branch) and 2.6.5 (2.6 branch),
the PACKET_MMAP buffer could hold only 32768 frames in a 32 bit architecture or
-16384 in a 64 bit architecture. For information on these kernel versions
-see http://pusa.uv.es/~ulisses/packet_mmap/packet_mmap.pre-2.4.26_2.6.5.txt
+16384 in a 64 bit architecture.
Block size limit
----------------
@@ -437,7 +436,7 @@ and the following flags apply:
Capture process
^^^^^^^^^^^^^^^
- from include/linux/if_packet.h
+From include/linux/if_packet.h::
#define TP_STATUS_COPY (1 << 1)
#define TP_STATUS_LOSING (1 << 2)