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John Baldwin 672dc4aea2 TCP reuses t_rxtshift to determine the backoff timer used for both the
persist state and the retransmit timer.  However, the code that implements
"bad retransmit recovery" only checks t_rxtshift to see if an ACK has been
received in during the first retransmit timeout window.  As a result, if
ticks has wrapped over to a negative value and a socket is in the persist
state, it can incorrectly treat an ACK from the remote peer as a
"bad retransmit recovery" and restore saved values such as snd_ssthresh and
snd_cwnd.  However, if the socket has never had a retransmit timeout, then
these saved values will be zero, so snd_ssthresh and snd_cwnd will be set
to 0.

If the socket is in fast recovery (this can be caused by excessive
duplicate ACKs such as those fixed by 220794), then each ACK that arrives
triggers either NewReno or SACK partial ACK handling which clamps snd_cwnd
to be no larger than snd_ssthresh.  In effect, the socket's send window
is permamently stuck at 0 even though the remote peer is advertising a
much larger window and pending data is only sent via TCP window probes
(so one byte every few seconds).

Fix this by adding a new TCP pcb flag (TF_PREVVALID) that indicates that
the various snd_*_prev fields in the pcb are valid and only perform
"bad retransmit recovery" if this flag is set in the pcb.  The flag is set
on the first retransmit timeout that occurs and is cleared on subsequent
retransmit timeouts or when entering the persist state.

Reviewed by:	bz
MFC after:	2 weeks
2011-04-29 15:40:12 +00:00
bin sh: Set $? to 0 for background commands. 2011-04-25 20:54:12 +00:00
cddl Fix 'zfs list <path>' handling. If the path was found, the 'ret' variable was 2011-04-12 20:31:33 +00:00
contrib Remove unused GPL files from tcsh. 2011-04-28 14:43:38 +00:00
crypto Fix Incorrectly formatted ClientHello SSL/TLS handshake messages could 2011-02-12 21:30:46 +00:00
etc Fix module names and dependencies so the NFS clients will 2011-04-27 20:42:30 +00:00
games Improve the distributeworld target in Makefile.inc1 and update the release 2011-03-02 14:39:26 +00:00
gnu Remove GNU man implemenation now that the BSD version has cooked for a while. 2011-04-21 07:14:10 +00:00
include * Add the readline(3) API to libedit. The libedit versions of 2011-04-05 18:41:01 +00:00
kerberos5
lib Protect the reachover built symbols after the SHA256/512 crypt(3) addition. 2011-04-27 21:33:56 +00:00
libexec rtld: eliminate double call to close(2) that may occur in load_object 2011-03-25 18:23:10 +00:00
release Mention the memstick target here. 2011-04-18 13:20:54 +00:00
rescue Finally... Import the latest open-source ZFS version - (SPA) 28. 2011-02-27 19:41:40 +00:00
sbin Another man page update related to the switchover of the 2011-04-29 01:14:12 +00:00
secure Fix some leftover binaries and shared libraries in the system that still 2011-02-15 22:03:09 +00:00
share Exar driver for X3100 10GbE Server/Storage adapters 2011-04-28 14:33:15 +00:00
sys TCP reuses t_rxtshift to determine the backoff timer used for both the 2011-04-29 15:40:12 +00:00
tools A diagnostic tool to go along with the vxge(4) 10GbE driver. 2011-04-28 16:29:19 +00:00
usr.bin Raise rlogin back to a WARNS level of 6. 2011-04-27 17:36:37 +00:00
usr.sbin Add a 'show progress' command that shows a summary of all in-progress 2011-04-29 14:06:37 +00:00
COPYRIGHT
LOCKS
MAINTAINERS - Initial release of bxe(4) to support Broadcom NetXtreme II 10GbE. 2011-03-14 22:42:41 +00:00
Makefile If building (custom) FreeBSD images people tend to patch param.h. In case 2011-04-12 02:07:23 +00:00
Makefile.inc1 Note which of the built kernels is being installed. 2011-04-22 17:10:51 +00:00
Makefile.mips Retire TARGET_ABI. 2011-01-07 20:26:33 +00:00
ObsoleteFiles.inc Remove libobjc and other Objective-C related components, as these are 2011-04-17 21:03:23 +00:00
README
UPDATING This patch changes head so that the default NFS client is now the new 2011-04-27 17:51:51 +00:00

This is the top level of the FreeBSD source directory.  This file
was last revised on:
$FreeBSD$

For copyright information, please see the file COPYRIGHT in this
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The Makefile in this directory supports a number of targets for
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everything in the FreeBSD system from the source tree except the
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http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/makeworld.html
for more information, including setting make(1) variables.

The ``buildkernel'' and ``installkernel'' targets build and install
the kernel and the modules (see below).  Please see the top of
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Building a kernel is a somewhat more involved process, documentation
for which can be found at:
   http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/kernelconfig.html
And in the config(8) man page.
Note: If you want to build and install the kernel with the
``buildkernel'' and ``installkernel'' targets, you might need to build
world before.  More information is available in the handbook.

The sample kernel configuration files reside in the sys/<arch>/conf
sub-directory (assuming that you've installed the kernel sources), the
file named GENERIC being the one used to build your initial installation
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LINT file, but in contrast to LINT, it is not buildable as a kernel but a
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Source Roadmap:
---------------
bin		System/user commands.

cddl		Various commands and libraries under the Common Development
		and Distribution License.

contrib		Packages contributed by 3rd parties.

crypto		Cryptography stuff (see crypto/README).

etc		Template files for /etc.

games		Amusements.

gnu		Various commands and libraries under the GNU Public License.
		Please see gnu/COPYING* for more information.

include		System include files.

kerberos5	Kerberos5 (Heimdal) package.

lib		System libraries.

libexec		System daemons.

release		Release building Makefile & associated tools.

rescue		Build system for statically linked /rescue utilities.

sbin		System commands.

secure		Cryptographic libraries and commands.

share		Shared resources.

sys		Kernel sources.

tools		Utilities for regression testing and miscellaneous tasks.

usr.bin		User commands.

usr.sbin	System administration commands.


For information on synchronizing your source tree with one or more of
the FreeBSD Project's development branches, please see:

  http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/synching.html