Commit Graph

31 Commits

Author SHA1 Message Date
Mohan Srinivasan
1714e18e79 Eliminate debug code that catches bugs in the hinting of sack variables
(tcp_sack_output_debug checks cached hints aginst computed values by walking the
scoreboard and reports discrepancies). The sack hinting code has been stable for
many months now so it is time for the debug code to go. Leaving tcp_sack_output_debug
ifdef'ed out in case we need to resurrect it at a later point.
2006-04-06 17:21:16 +00:00
Mohan Srinivasan
1f65c2cd31 Certain (bad) values of sack blocks can end up corrupting the sack scoreboard.
Make the checks in tcp_sack_doack() more robust to prevent this.

Submitted by: Raja Mukerji (raja@mukerji.com)
Reviewed by:  Mohan Srinivasan
2006-04-05 00:11:04 +00:00
Andre Oppermann
8e8aab7aec Remove unneeded includes and provide more accurate description
to others.

Submitted by:	garys
PR:		kern/86437
2006-02-18 17:05:00 +00:00
Paul Saab
d0a14f55c3 Fix for a bug that causes SACK scoreboard corruption when the limit
on holes per connection is reached.

Reported by:	Patrik Roos
Submitted by:	Mohan Srinivasan
Reviewed by:	Raja Mukerji, Noritoshi Demizu
2005-11-21 19:22:10 +00:00
Andre Oppermann
ef8fd90476 Remove unnecessary IPSEC includes.
MFC after:	2 weeks
Sponsored by:	TCP/IP Optimization Fundraise 2005
2005-08-23 14:42:40 +00:00
Paul Saab
5a53ca1627 - Postpone SACK option processing until after PAWS checks. SACK option
processing is now done in the ACK processing case.
- Merge tcp_sack_option() and tcp_del_sackholes() into a new function
  called tcp_sack_doack().
- Test (SEG.ACK < SND.MAX) before processing the ACK.

Submitted by:	Noritoshi Demizu
Reveiewed by:	Mohan Srinivasan, Raja Mukerji
Approved by:	re
2005-06-27 22:27:42 +00:00
Paul Saab
9004ded9df Fix for a bug in tcp_sack_option() causing crashes.
Submitted by:	Noritoshi Demizu, Mohan Srinivasan.
Approved by:	re (scottl blanket SACK)
2005-06-23 00:18:54 +00:00
Paul Saab
e912f906d0 Fix a mis-merge. Remove a redundant call to tcp_sackhole_insert
Submitted by:	Mohan Srinivasan
2005-06-09 17:55:29 +00:00
Paul Saab
8b9bbaaa94 Fix for a crash in tcp_sack_option() caused by hitting the limit on
the number of sack holes.

Reported by:	Andrey Chernov
Submitted by:	Noritoshi Demizu
Reviewed by:	Raja Mukerji
2005-06-09 14:01:04 +00:00
Paul Saab
db4b83fe49 Fix for a bug in the change that walks the scoreboard backwards from
the tail (in tcp_sack_option()). The bug was caused by incorrect
accounting of the retransmitted bytes in the sackhint.

Reported by:    Kris Kennaway.
Submitted by:   Noritoshi Demizu.
2005-06-06 19:46:53 +00:00
Paul Saab
9d17a7a64a Changes to tcp_sack_option() that
- Walks the scoreboard backwards from the tail to reduce the number of
  comparisons for each sack option received.
- Introduce functions to add/remove sack scoreboard elements, making
  the code more readable.

Submitted by:   Noritoshi Demizu
Reviewed by:    Raja Mukerji, Mohan Srinivasan
2005-06-04 08:03:28 +00:00
Paul Saab
808f11b768 This is conform with the terminology in
M.Mathis and J.Mahdavi,
  "Forward Acknowledgement: Refining TCP Congestion Control"
  SIGCOMM'96, August 1996.

Submitted by:   Noritoshi Demizu, Raja Mukerji
2005-05-25 17:55:27 +00:00
Paul Saab
64b5fbaa04 Rewrite of tcp_sack_option(). Kentaro Kurahone (NetBSD) pointed out
that if we sort the incoming SACK blocks, we can update the scoreboard
in one pass of the scoreboard. The added overhead of sorting upto 4
sack blocks is much lower than traversing (potentially) large
scoreboards multiple times. The code was updating the scoreboard with
multiple passes over it (once for each sack option). The rewrite fixes
that, reducing the complexity of the main loop from O(n^2) to O(n).

Submitted by:   Mohan Srinivasan, Noritoshi Demizu.
Reviewed by:    Raja Mukerji.
2005-05-23 19:22:48 +00:00
Paul Saab
4fc5324557 Introduce routines to alloc/free sack holes. This cleans up the code
considerably.

Submitted by:   Noritoshi Demizu.
Reviewed by:    Raja Mukerji, Mohan Srinivasan.
2005-05-16 19:26:46 +00:00
Paul Saab
fdace17f81 Fix for a bug where the "nexthole" sack hint is out of sync with the
real next hole to retransmit from the scoreboard, caused by a bug
which did not update the "nexthole" hint in one case in
tcp_sack_option().

Reported by:    Daniel Eriksson
Submitted by:   Mohan Srinivasan
2005-05-13 18:02:02 +00:00
Paul Saab
0077b0163f When looking for the next hole to retransmit from the scoreboard,
or to compute the total retransmitted bytes in this sack recovery
episode, the scoreboard is traversed. While in sack recovery, this
traversal occurs on every call to tcp_output(), every dupack and
every partial ack. The scoreboard could potentially get quite large,
making this traversal expensive.

This change optimizes this by storing hints (for the next hole to
retransmit and the total retransmitted bytes in this sack recovery
episode) reducing the complexity to find these values from O(n) to
constant time.

The debug code that sanity checks the hints against the computed
value will be removed eventually.

Submitted by:   Mohan Srinivasan, Noritoshi Demizu, Raja Mukerji.
2005-05-11 21:37:42 +00:00
Paul Saab
a6235da61e - Make the sack scoreboard logic use the TAILQ macros. This improves
code readability and facilitates some anticipated optimizations in
  tcp_sack_option().
- Remove tcp_print_holes() and TCP_SACK_DEBUG.

Submitted by:	Raja Mukerji.
Reviewed by:	Mohan Srinivasan, Noritoshi Demizu.
2005-04-21 20:11:01 +00:00
Paul Saab
b7c755717c Rewrite of tcp_update_sack_list() to make it simpler and more readable
than our original OpenBSD derived version.

Submitted by:	Noritoshi Demizu
Reviewed by:	Mohan Srinivasan, Raja Mukerji
2005-04-18 18:10:56 +00:00
Paul Saab
25e6f9ed4b Fix for a TCP SACK bug where more than (win/2) bytes could have been
in flight in SACK recovery.

Found by:	Noritoshi Demizu
Submitted by:	Mohan Srinivasan <mohans at yahoo-inc dot com>
		Noritoshi Demizu <demizu at dd dot ij4u dot or dot jp>
		Raja Mukerji <raja at moselle dot com>
2005-04-14 20:09:52 +00:00
Paul Saab
b962fa74b5 When the rightmost SACK block expands, rcv_lastsack should be updated.
(Fix for kern/78226).

Submitted by : Noritoshi Demizu <demizu at dd dot iij4u dot or dot jp>
Reviewed by  : Mohan Srinivasan (mohans at yahoo-inc dot com),
               Raja Mukerji (raja at moselle dot com).
2005-04-10 05:20:10 +00:00
Paul Saab
da39f5b963 Remove some unused sack fields.
Submitted by : Noritoshi Demizu, Mohan Srinivasan.
2005-04-10 05:19:22 +00:00
Paul Saab
e891d82b56 Add limits on the number of elements in the sack scoreboard both
per-connection and globally. This eliminates potential DoS attacks
where SACK scoreboard elements tie up too much memory.

Submitted by:	Raja Mukerji (raja at moselle dot com).
Reviewed by:	Mohan Srinivasan (mohans at yahoo-inc dot com).
2005-03-09 23:14:10 +00:00
Paul Saab
8291294024 If the receiver sends an ack that is out of [snd_una, snd_max],
ignore the sack options in that segment. Else we'd end up
corrupting the scoreboard.

Found by:	Raja Mukerji (raja at moselle dot com)
Submitted by:	Mohan Srinivasan
2005-02-27 20:39:04 +00:00
Paul Saab
7643c37cf2 Remove 2 (SACK) fields from the tcpcb. These are only used by a
function that is called from tcp_input(), so they oughta be passed on
the stack instead of stuck in the tcpcb.

Submitted by:	Mohan Srinivasan
2005-02-17 23:04:56 +00:00
Paul Saab
8db456bf17 - Retransmit just one segment on initiation of SACK recovery.
Remove the SACK "initburst" sysctl.
- Fix bugs in SACK dupack and partialack handling that can cause
  large bursts while in SACK recovery.

Submitted by:	Mohan Srinivasan
2005-02-14 21:01:08 +00:00
Warner Losh
c398230b64 /* -> /*- for license, minor formatting changes 2005-01-07 01:45:51 +00:00
Robert Watson
c427483381 Add a matching tunable for net.inet.tcp.sack.enable sysctl. 2004-10-26 08:59:09 +00:00
Paul Saab
a55db2b6e6 - Estimate the amount of data in flight in sack recovery and use it
to control the packets injected while in sack recovery (for both
  retransmissions and new data).
- Cleanups to the sack codepaths in tcp_output.c and tcp_sack.c.
- Add a new sysctl (net.inet.tcp.sack.initburst) that controls the
  number of sack retransmissions done upon initiation of sack recovery.

Submitted by:	Mohan Srinivasan <mohans@yahoo-inc.com>
2004-10-05 18:36:24 +00:00
Andre Oppermann
9b932e9e04 Convert ipfw to use PFIL_HOOKS. This is change is transparent to userland
and preserves the ipfw ABI.  The ipfw core packet inspection and filtering
functions have not been changed, only how ipfw is invoked is different.

However there are many changes how ipfw is and its add-on's are handled:

 In general ipfw is now called through the PFIL_HOOKS and most associated
 magic, that was in ip_input() or ip_output() previously, is now done in
 ipfw_check_[in|out]() in the ipfw PFIL handler.

 IPDIVERT is entirely handled within the ipfw PFIL handlers.  A packet to
 be diverted is checked if it is fragmented, if yes, ip_reass() gets in for
 reassembly.  If not, or all fragments arrived and the packet is complete,
 divert_packet is called directly.  For 'tee' no reassembly attempt is made
 and a copy of the packet is sent to the divert socket unmodified.  The
 original packet continues its way through ip_input/output().

 ipfw 'forward' is done via m_tag's.  The ipfw PFIL handlers tag the packet
 with the new destination sockaddr_in.  A check if the new destination is a
 local IP address is made and the m_flags are set appropriately.  ip_input()
 and ip_output() have some more work to do here.  For ip_input() the m_flags
 are checked and a packet for us is directly sent to the 'ours' section for
 further processing.  Destination changes on the input path are only tagged
 and the 'srcrt' flag to ip_forward() is set to disable destination checks
 and ICMP replies at this stage.  The tag is going to be handled on output.
 ip_output() again checks for m_flags and the 'ours' tag.  If found, the
 packet will be dropped back to the IP netisr where it is going to be picked
 up by ip_input() again and the directly sent to the 'ours' section.  When
 only the destination changes, the route's 'dst' is overwritten with the
 new destination from the forward m_tag.  Then it jumps back at the route
 lookup again and skips the firewall check because it has been marked with
 M_SKIP_FIREWALL.  ipfw 'forward' has to be compiled into the kernel with
 'option IPFIREWALL_FORWARD' to enable it.

 DUMMYNET is entirely handled within the ipfw PFIL handlers.  A packet for
 a dummynet pipe or queue is directly sent to dummynet_io().  Dummynet will
 then inject it back into ip_input/ip_output() after it has served its time.
 Dummynet packets are tagged and will continue from the next rule when they
 hit the ipfw PFIL handlers again after re-injection.

 BRIDGING and IPFW_ETHER are not changed yet and use ipfw_chk() directly as
 they did before.  Later this will be changed to dedicated ETHER PFIL_HOOKS.

More detailed changes to the code:

 conf/files
	Add netinet/ip_fw_pfil.c.

 conf/options
	Add IPFIREWALL_FORWARD option.

 modules/ipfw/Makefile
	Add ip_fw_pfil.c.

 net/bridge.c
	Disable PFIL_HOOKS if ipfw for bridging is active.  Bridging ipfw
	is still directly invoked to handle layer2 headers and packets would
	get a double ipfw when run through PFIL_HOOKS as well.

 netinet/ip_divert.c
	Removed divert_clone() function.  It is no longer used.

 netinet/ip_dummynet.[ch]
	Neither the route 'ro' nor the destination 'dst' need to be stored
	while in dummynet transit.  Structure members and associated macros
	are removed.

 netinet/ip_fastfwd.c
	Removed all direct ipfw handling code and replace it with the new
	'ipfw forward' handling code.

 netinet/ip_fw.h
	Removed 'ro' and 'dst' from struct ip_fw_args.

 netinet/ip_fw2.c
	(Re)moved some global variables and the module handling.

 netinet/ip_fw_pfil.c
	New file containing the ipfw PFIL handlers and module initialization.

 netinet/ip_input.c
	Removed all direct ipfw handling code and replace it with the new
	'ipfw forward' handling code.  ip_forward() does not longer require
	the 'next_hop' struct sockaddr_in argument.  Disable early checks
	if 'srcrt' is set.

 netinet/ip_output.c
	Removed all direct ipfw handling code and replace it with the new
	'ipfw forward' handling code.

 netinet/ip_var.h
	Add ip_reass() as general function.  (Used from ipfw PFIL handlers
	for IPDIVERT.)

 netinet/raw_ip.c
	Directly check if ipfw and dummynet control pointers are active.

 netinet/tcp_input.c
	Rework the 'ipfw forward' to local code to work with the new way of
	forward tags.

 netinet/tcp_sack.c
	Remove include 'opt_ipfw.h' which is not needed here.

 sys/mbuf.h
	Remove m_claim_next() macro which was exclusively for ipfw 'forward'
	and is no longer needed.

Approved by:	re (scottl)
2004-08-17 22:05:54 +00:00
Robert Watson
a4f757cd5d White space cleanup for netinet before branch:
- Trailing tab/space cleanup
- Remove spurious spaces between or before tabs

This change avoids touching files that Andre likely has in his working
set for PFIL hooks changes for IPFW/DUMMYNET.

Approved by:	re (scottl)
Submitted by:	Xin LI <delphij@frontfree.net>
2004-08-16 18:32:07 +00:00
Paul Saab
6d90faf3d8 Add support for TCP Selective Acknowledgements. The work for this
originated on RELENG_4 and was ported to -CURRENT.

The scoreboarding code was obtained from OpenBSD, and many
of the remaining changes were inspired by OpenBSD, but not
taken directly from there.

You can enable/disable sack using net.inet.tcp.do_sack. You can
also limit the number of sack holes that all senders can have in
the scoreboard with net.inet.tcp.sackhole_limit.

Reviewed by:	gnn
Obtained from:	Yahoo! (Mohan Srinivasan, Jayanth Vijayaraghavan)
2004-06-23 21:04:37 +00:00