There was an off-by-one error in the comments describing the
highest_sack field in struct tcp_sock. The comments previously claimed
that it was the "start sequence of the highest skb with SACKed
bit". This commit fixes the comments to note that it is the "start
sequence of the skb just *after* the highest skb with SACKed bit".
Signed-off-by: NNeal Cardwell <ncardwell@google.com>
Acked-by: NIlpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Some of our machines were reporting:

TCP: too many of orphaned sockets

even when the number of orphaned sockets was well below the
limit.

We print a different message depending on whether we're out
of TCP memory or there are too many orphaned sockets.

Also move the check out of line and cleanup the messages
that were printed.
Signed-off-by: NArun Sharma <asharma@fb.com>
Suggested-by: NMohan Srinivasan <mohan@fb.com>
Cc: netdev@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: David Miller <davem@davemloft.net>
Cc: Glauber Costa <glommer@parallels.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

sysctl_tcp_mem() initialization was moved to sysctl_tcp_ipv4.c
in commit 3dc43e3e, since it
became a per-ns value.

That code, however, will never run when CONFIG_SYSCTL is
disabled, leading to bogus values on those fields - causing hung
TCP sockets.

This patch fixes it by keeping an initialization code in
tcp_init(). It will be overwritten by the first net namespace
init if CONFIG_SYSCTL is compiled in, and do the right thing if
it is compiled out.

It is also named properly as tcp_init_mem(), to properly signal
its non-sysctl side effect on TCP limits.
Reported-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NGlauber Costa <glommer@parallels.com>
Cc: David S. Miller <davem@davemloft.net>
Link: http://lkml.kernel.org/r/4F22D05A.8030604@parallels.com
[ renamed the function, tidied up the changelog a bit ]
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

to record the state of SACK/FACK and DSACK for better readability and maintenance.
Signed-off-by: NVijay Subramanian <subramanian.vijay@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch allows each namespace to independently set up
its levels for tcp memory pressure thresholds. This patch
alone does not buy much: we need to make this values
per group of process somehow. This is achieved in the
patches that follows in this patchset.
Signed-off-by: NGlauber Costa <glommer@parallels.com>
Reviewed-by: NKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
CC: David S. Miller <davem@davemloft.net>
CC: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch replaces all uses of struct sock fields' memory_pressure,
memory_allocated, sockets_allocated, and sysctl_mem to acessor
macros. Those macros can either receive a socket argument, or a mem_cgroup
argument, depending on the context they live in.

Since we're only doing a macro wrapping here, no performance impact at all is
expected in the case where we don't have cgroups disabled.
Signed-off-by: NGlauber Costa <glommer@parallels.com>
Reviewed-by: NHiroyouki Kamezawa <kamezawa.hiroyu@jp.fujitsu.com>
CC: David S. Miller <davem@davemloft.net>
CC: Eric W. Biederman <ebiederm@xmission.com>
CC: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Instead of testing defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Since 2005 (c1b4a7e6)
tcp_tso_should_defer has been using tcp_max_burst() as a target limit
for deciding how large to make outgoing TSO packets when not using
sysctl_tcp_tso_win_divisor. But since 2008
(dd9e0dda) tcp_max_burst() returns the
reordering degree. We should not have tcp_tso_should_defer attempt to
build larger segments just because there is more reordering. This
commit splits the notion of deferral size used in TSO from the notion
of burst size used in cwnd moderation, and returns the TSO deferral
limit to its original value.
Signed-off-by: NNeal Cardwell <ncardwell@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

v2:	add couple missing conversions in drivers
	split unexporting netdev_fix_features()
	implemented %pNF
	convert sock::sk_route_(no?)caps
Signed-off-by: NMichał Mirosław <mirq-linux@rere.qmqm.pl>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

the tcp and udp code creates a set of struct file_operations at runtime
while it can also be done at compile time, with the added benefit of then
having these file operations be const.

the trickiest part was to get the "THIS_MODULE" reference right; the naive
method of declaring a struct in the place of registration would not work
for this reason.
Signed-off-by: NArjan van de Ven <arjan@linux.intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

It was enabled by default and the messages guarded
by the define are useful.
Signed-off-by: NFlavio Leitner <fbl@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Now tcp_md5_hash_header() has a const tcphdr argument, we can add more
const attributes to callers.
Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

tcp_md5_hash_header() writes into skb header a temporary zero value,
this might confuse other users of this area.

Since tcphdr is small (20 bytes), copy it in a temporary variable and
make the change in the copy.
Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Adding const qualifiers to pointers can ease code review, and spot some
bugs. It might allow compiler to optimize code further.

For example, is it legal to temporary write a null cksum into tcphdr
in tcp_md5_hash_header() ? I am afraid a sniffer could catch the
temporary null value...
Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Rename struct tcp_skb_cb "flags" to "tcp_flags" to ease code review and
maintenance.

Its content is a combination of FIN/SYN/RST/PSH/ACK/URG/ECE/CWR flags
Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

struct tcp_skb_cb contains a "flags" field containing either tcp flags
or IP dsfield depending on context (input or output path)

Introduce ip_dsfield to make the difference clear and ease maintenance.
If later we want to save space, we can union flags/ip_dsfield
Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

While playing with a new ADSL box at home, I discovered that ECN
blackhole can trigger suboptimal quickack mode on linux : We send one
ACK for each incoming data frame, without any delay and eventual
piggyback.

This is because TCP_ECN_check_ce() considers that if no ECT is seen on a
segment, this is because this segment was a retransmit.

Refine this heuristic and apply it only if we seen ECT in a previous
segment, to detect ECN blackhole at IP level.
Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com>
CC: Jamal Hadi Salim <jhs@mojatatu.com>
CC: Jerry Chu <hkchu@google.com>
CC: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
CC: Jim Gettys <jg@freedesktop.org>
CC: Dave Taht <dave.taht@gmail.com>
Acked-by: NIlpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

commit 946cedcc (tcp: Change possible SYN flooding messages)
added a build error if CONFIG_SYN_COOKIES=n
Reported-by: NMarkus Trippelsdorf <markus@trippelsdorf.de>
Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

tcp_md5sig_pool is currently an 'array' (a percpu object) of pointers to
struct tcp_md5sig_pool. Only the pointers are NUMA aware, but objects
themselves are all allocated on a single node.

Remove this extra indirection to get proper percpu memory (NUMA aware)
and make code simpler.
Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

"Possible SYN flooding on port xxxx " messages can fill logs on servers.

Change logic to log the message only once per listener, and add two new
SNMP counters to track :

TCPReqQFullDoCookies : number of times a SYNCOOKIE was replied to client

TCPReqQFullDrop : number of times a SYN request was dropped because
syncookies were not enabled.

Based on a prior patch from Tom Herbert, and suggestions from David.
Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com>
CC: Tom Herbert <therbert@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch lowers the default initRTO from 3secs to 1sec per
RFC2988bis. It falls back to 3secs if the SYN or SYN-ACK packet
has been retransmitted, AND the TCP timestamp option is not on.

It also adds support to take RTT sample during 3WHS on the passive
open side, just like its active open counterpart, and uses it, if
valid, to seed the initRTO for the data transmission phase.

The patch also resets ssthresh to its initial default at the
beginning of the data transmission phase, and reduces cwnd to 1 if
there has been MORE THAN ONE retransmission during 3WHS per RFC5681.
Signed-off-by: NH.K. Jerry Chu <hkchu@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Now, TCP_CHECK_TIMER is not used for debuging, it does nothing.
And, it has been there for several years, maybe 6 years.

Remove it to keep code clearer.
Signed-off-by: NShan Wei <shanwei@cn.fujitsu.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Suggested by Alexander Zimmermann
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NDavid S. Miller <davem@davemloft.net>
Acked-by: NNandita Dukkipati <nanditad@google.com>

Quoting Ben Hutchings: we presumably won't be defining features that
can only be enabled on 64-bit architectures.

Occurences found by `grep -r` on net/, drivers/net, include/

[ Move features and vlan_features next to each other in
  struct netdev, as per Eric Dumazet's suggestion -DaveM ]
Signed-off-by: NMichał Mirosław <mirq-linux@rere.qmqm.pl>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch changes the default initial receive window to 10 mss
(defined constant). The default window is limited to the maximum
of 10*1460 and 2*mss (when mss > 1460).

draft-ietf-tcpm-initcwnd-00 is a proposal to the IETF that recommends
increasing TCP's initial congestion window to 10 mss or about 15KB.
Leading up to this proposal were several large-scale live Internet
experiments with an initial congestion window of 10 mss (IW10), where
we showed that the average latency of HTTP responses improved by
approximately 10%. This was accompanied by a slight increase in
retransmission rate (0.5%), most of which is coming from applications
opening multiple simultaneous connections. To understand the extreme
worst case scenarios, and fairness issues (IW10 versus IW3), we further
conducted controlled testbed experiments. We came away finding minimal
negative impact even under low link bandwidths (dial-ups) and small
buffers.  These results are extremely encouraging to adopting IW10.

However, an initial congestion window of 10 mss is useless unless a TCP
receiver advertises an initial receive window of at least 10 mss.
Fortunately, in the large-scale Internet experiments we found that most
widely used operating systems advertised large initial receive windows
of 64KB, allowing us to experiment with a wide range of initial
congestion windows. Linux systems were among the few exceptions that
advertised a small receive window of 6KB. The purpose of this patch is
to fix this shortcoming.

References:
1. A comprehensive list of all IW10 references to date.
http://code.google.com/speed/protocols/tcpm-IW10.html

2. Paper describing results from large-scale Internet experiments with IW10.
http://ccr.sigcomm.org/drupal/?q=node/621

3. Controlled testbed experiments under worst case scenarios and a
fairness study.
http://www.ietf.org/proceedings/79/slides/tcpm-0.pdf

4. Raw test data from testbed experiments (Linux senders/receivers)
with initial congestion and receive windows of both 10 mss.
http://research.csc.ncsu.edu/netsrv/?q=content/iw10

5. Internet-Draft. Increasing TCP's Initial Window.
https://datatracker.ietf.org/doc/draft-ietf-tcpm-initcwnd/Signed-off-by: NNandita Dukkipati <nanditad@google.com>
Acked-by: NEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

These macros never be used, so remove them.
Signed-off-by: NShan Wei <shanwei@cn.fujitsu.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Some windows versions have wrong RFC1323 implementations, with SYN and
SYNACKS messages containing zero tcp timestamps.

We relaxed in commit fc1ad92d the passive connection case
(Windows connects to a linux machine), but the reverse case (linux
connects to a Windows machine) has an analogue problem when tsvals from
windows machine are 'negative' (high order bit set) : PAWS triggers and
we drops incoming messages.

Fix this by making zero ts_recent value special, allowing frame to be
processed.

Based on a report and initial patch from Dmitiy Balakin

Bugzilla reference : https://bugzilla.kernel.org/show_bug.cgi?id=24842

Reported-by: dmitriy.balakin@nicneiron.ru
Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

These macros have been defined for several years since v2.6.12-rc2（tracing by git）,
but never be used. So remove them.
Signed-off-by: NShan Wei <shanwei@cn.fujitsu.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The only thing AF-specific about remembering the timestamp
for a time-wait TCP socket is getting the peer.

Abstract that behind a new timewait_sock_ops vector.

Support for real IPV6 sockets is not filled in yet, but
curiously this makes timewait recycling start to work
for v4-mapped ipv6 sockets.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Then we can make a completely generic tcp_remember_stamp()
that uses ->get_peer() as a helper, minimizing the AF specific
code and minimizing the eventual code duplication when we implement
the ipv6 side of TW recycling.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Robin Holt tried to boot a 16TB machine and found some limits were
reached : sysctl_tcp_mem[2], sysctl_udp_mem[2]

We can switch infrastructure to use long "instead" of "int", now
atomic_long_t primitives are available for free.
Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com>
Reported-by: NRobin Holt <holt@sgi.com>
Reviewed-by: NRobin Holt <holt@sgi.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Function only used in tcp_input.c
Signed-off-by: NStephen Hemminger <shemminger@vyatta.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

If peer uses tiny MSS (say, 75 bytes) and similarly tiny advertised
window, the SWS logic will packetize to half the MSS unnecessarily.

This causes problems with some embedded devices.

However for large MSS devices we do want to half-MSS packetize
otherwise we never get enough packets into the pipe for things
like fast retransmit and recovery to work.

Be careful also to handle the case where MSS > window, otherwise
we'll never send until the probe timer.
Reported-by: Nツ Leandro Melo de Sales <leandroal@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This updates the use of larger initial windows, as originally specified in
RFC 3390, to use the newer IW values specified in RFC 5681, section 3.1.

The changes made in RFC 5681 are:
 a) the setting now is more clearly specified in units of segments (as the
    comments  by John Heffner emphasized, this was not very clear in RFC 3390);
 b) for connections with 1095 < SMSS <= 2190 there is now a change:
    - RFC 3390 says that IW <= 4380,
    - RFC 5681 says that IW = 3 * SMSS <= 6570.

Since RFC 3390 is older and "only" proposed standard, whereas the newer RFC 5681
is already draft standard, it seems preferable to use the newer IW variant.
Signed-off-by: NGerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch consolidates initial-window code common to TCP and CCID-2:
 * TCP uses RFC 3390 in a packet-oriented manner (tcp_input.c) and
 * CCID-2 uses RFC 3390 in packet-oriented manner (RFC 4341).
Signed-off-by: NGerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

As reported by Anton Blanchard when we use
percpu_counter_read_positive() to make our orphan socket limit checks,
the check can be off by up to num_cpus_online() * batch (which is 32
by default) which on a 128 cpu machine can be as large as the default
orphan limit itself.

Fix this by doing the full expensive sum check if the optimized check
triggers.
Reported-by: NAnton Blanchard <anton@samba.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
Acked-by: NEric Dumazet <eric.dumazet@gmail.com>

Correct comment stating sizeof(struct tcp_skb_cb) is 36 or 40, since its
44 bytes, since commit 951dbc8a ([IPV6]: Move nextheader offset
to the IP6CB).
Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

a new boolean flag no_autobind is added to structure proto to avoid the autobind
calls when the protocol is TCP. Then sock_rps_record_flow() is called int the
TCP's sendmsg() and sendpage() pathes.
Signed-off-by: NChangli Gao <xiaosuo@gmail.com>
----
 include/net/inet_common.h |    4 ++++
 include/net/sock.h        |    1 +
 include/net/tcp.h         |    8 ++++----
 net/ipv4/af_inet.c        |   15 +++++++++------
 net/ipv4/tcp.c            |   11 +++++------
 net/ipv4/tcp_ipv4.c       |    3 +++
 net/ipv6/af_inet6.c       |    8 ++++----
 net/ipv6/tcp_ipv6.c       |    3 +++
 8 files changed, 33 insertions(+), 20 deletions(-)
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

remove useless blanks.
Signed-off-by: NChangli Gao <xiaosuo@gmail.com>
----
 include/net/inet_common.h |   55 ++++-------
 include/net/tcp.h         |  222 +++++++++++++++++-----------------------------
 include/net/udp.h         |   38 +++----
 3 files changed, 123 insertions(+), 192 deletions(-)
Signed-off-by: NDavid S. Miller <davem@davemloft.net>