Commit Graph

48 Commits

Author SHA1 Message Date
Andre Oppermann
1c18314d17 Remove the TCP inflight bandwidth limiter as announced in r211315
to give way for the pluggable congestion control framework.  It is
the task of the congestion control algorithm to set the congestion
window and amount of inflight data without external interference.

In 'struct tcpcb' the variables previously used by the inflight
limiter are renamed to spares to keep the ABI intact and to have
some more space for future extensions.

In 'struct tcp_info' the variable 'tcpi_snd_bwnd' is not removed to
preserve the ABI.  It is always set to 0.

In siftr.c in 'struct pkt_node' the variable 'snd_bwnd' is not removed
to preserve the ABI.  It is always set to 0.

These unused variable in the various structures may be reused in the
future or garbage collected before the next release or at some other
point when an ABI change happens anyway for other reasons.

No MFC is planned.  The inflight bandwidth limiter stays disabled by
default in the other branches but remains available.
2010-09-16 21:06:45 +00:00
Andre Oppermann
2c9879e8d3 Improve comment to TCP_MINMSS by taking the wording from lstewart (with
a small difference in the last paragraph though) as suggested by jhb.

Clarify that the 'reviewed by' in r212653 by lstewart was for the
functional change, not the comments in the committed version.
2010-09-16 12:13:06 +00:00
Andre Oppermann
c183b9c683 Change the default MSS for IPv4 and IPv6 TCP connections from an
artificial power-of-2 rounded number to their real values specified
in RFC879 and RFC2460.

From the history and existing comments it appears that the rounded
numbers were intended to be advantageous for the kernel and mbuf
system.  However this hasn't been the case at for at least a long
time.  The mbuf clusters used in tcp_output() have enough space
to hold the larger real value for the default MSS for both IPv4 and
IPv6.  Note that the default MSS is only used when path MTU discovery
is disabled.

Update and expand related comments.

Reviewed by:	lsteward (including some word-smithing)
MFC after:	2 weeks
2010-09-15 10:39:30 +00:00
Luigi Rizzo
dc5fd2595c use u_char instead of u_int for short bitfields.
For our compiler the two constructs are completely equivalent, but
some compilers (including MSC and tcc) use the base type for alignment,
which in the cases touched here result in aligning the bitfields
to 32 bit instead of the 8 bit that is meant here.

Note that almost all other headers where small bitfields
are used have u_int8_t instead of u_int.

MFC after:	3 days
2010-02-01 14:13:44 +00:00
John Baldwin
43d9473499 - Rename the __tcpi_(snd|rcv)_mss fields of the tcp_info structure to remove
the leading underscores since they are now implemented.
- Implement the tcpi_rto and tcpi_last_data_recv fields in the tcp_info
  structure.

Reviewed by:	rwatson
MFC after:	2 weeks
2009-12-22 15:47:40 +00:00
Kip Macy
535fbad68f add rcv_nxt, snd_nxt, and toe offload id to FreeBSD-specific
extension fields for tcp_info
2008-05-05 20:13:31 +00:00
Andre Oppermann
c343c524e1 Use #defines for TCP options padding after EOL to be consistent.
Reviewed by:	bz
2008-04-07 18:43:59 +00:00
Kip Macy
ee939bbf7e Add socket option for setting and retrieving the congestion control algorithm.
The name used is to allow compatibility with Linux.
2007-12-16 03:30:07 +00:00
Andre Oppermann
faedb66c2a The printf %b list in PRINT_TH_FLAGS has to be in octal numbering.
Thus convert \8 to \10 and the warnings go away.

Pointed out by:	sam, ru, thompsa
2007-05-25 21:28:49 +00:00
Andre Oppermann
a250f3820c Add CWR back into the PRINT_TH_FLAGS list as gcc42 doesn't complain
about \8 in a string anymore.
2007-05-23 19:16:21 +00:00
Andre Oppermann
df541e5fc1 Add tcp_log_addrs() function to generate and standardized TCP log line
for use thoughout the tcp subsystem.

It is IPv4 and IPv6 aware creates a line in the following format:

 "TCP: [1.2.3.4]:50332 to [1.2.3.4]:80 tcpflags <RST>"

A "\n" is not included at the end.  The caller is supposed to add
further information after the standard tcp log header.

The function returns a NUL terminated string which the caller has
to free(s, M_TCPLOG) after use.  All memory allocation is done
with M_NOWAIT and the return value may be NULL in memory shortage
situations.

Either struct in_conninfo || (struct tcphdr && (struct ip || struct
ip6_hdr) have to be supplied.

Due to ip[6].h header inclusion limitations and ordering issues the
struct ip and struct ip6_hdr parameters have to be casted and passed
as void * pointers.

tcp_log_addrs(struct in_conninfo *inc, struct tcphdr *th, void *ip4hdr,
    void *ip6hdr)

Usage example:

 struct ip *ip;
 char *tcplog;

 if (tcplog = tcp_log_addrs(NULL, th, (void *)ip, NULL)) {
	log(LOG_DEBUG, "%s; %s: Connection attempt to closed port\n",
	    tcplog, __func__);
	free(s, M_TCPLOG);
 }
2007-05-18 19:58:37 +00:00
Andre Oppermann
0d957bba48 o Remove unused and redundant TCP option definitions
o Replace usage of MAX_TCPOPTLEN with the correctly constructed and
  derived MAX_TCPOPTLEN
2007-04-20 15:08:09 +00:00
Andre Oppermann
e406f5a1c9 Remove tcp_minmssoverload DoS detection logic. The problem it tried to
protect us from wasn't really there and it only bloats the code.  Should
the problem surface in the future we can simply resurrect it from cvs
history.
2007-03-21 18:05:54 +00:00
Andre Oppermann
02a1a64357 Consolidate insertion of TCP options into a segment from within tcp_output()
and syncache_respond() into its own generic function tcp_addoptions().

tcp_addoptions() is alignment agnostic and does optimal packing in all cases.

In struct tcpopt rename to_requested_s_scale to just to_wscale.

Add a comment with quote from RFC1323: "The Window field in a SYN (i.e.,
a <SYN> or <SYN,ACK>) segment itself is never scaled."

Reviewed by:	silby, mohans, julian
Sponsored by:	TCP/IP Optimization Fundraise 2005
2007-03-15 15:59:28 +00:00
Bruce M Simpson
1baaf8347c Expose smoothed RTT and RTT variance measurements to userland via
socket option TCP_INFO.
Note that the units used in the original Linux API are in microseconds,
so use a 64-bit mantissa to convert FreeBSD's internal measurements
from struct tcpcb from ticks.
2007-02-02 18:34:18 +00:00
Andre Oppermann
da3482e0f6 Add missing TH_PUSH to the TH_FLAGS enumeration.
Submitted by:	Andre Albsmeier <Andre.Albsmeier-at-siemens.com>
PR:		kern/85203
2006-02-18 16:50:08 +00:00
Paul Saab
b24de0e665 Fix up the comment for MAX_SACK_BLKS.
Submitted by:	Noritoshi Demizu
2005-08-24 02:47:16 +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
Warner Losh
c398230b64 /* -> /*- for license, minor formatting changes 2005-01-07 01:45:51 +00:00
Robert Watson
c8443a1dc0 Do export the advertised receive window via the tcpi_rcv_space field of
struct tcp_info.
2004-11-27 20:20:11 +00:00
Robert Watson
b8af5dfa81 Implement parts of the TCP_INFO socket option as found in Linux 2.6.
This socket option allows processes query a TCP socket for some low
level transmission details, such as the current send, bandwidth, and
congestion windows.  Linux provides a 'struct tcpinfo' structure
containing various variables, rather than separate socket options;
this makes the API somewhat fragile as it makes it dificult to add
new entries of interest as requirements and implementation evolve.
As such, I've included a large pad at the end of the structure.
Right now, relatively few of the Linux API fields are filled in, and
some contain no logical equivilent on FreeBSD.  I've include __'d
entries in the structure to make it easier to figure ou what is and
isn't omitted.  This API/ABI should be considered unstable for the
time being.
2004-11-26 18:58:46 +00:00
Andre Oppermann
c94c54e4df Remove RFC1644 T/TCP support from the TCP side of the network stack.
A complete rationale and discussion is given in this message
and the resulting discussion:

 http://docs.freebsd.org/cgi/mid.cgi?4177C8AD.6060706

Note that this commit removes only the functional part of T/TCP
from the tcp_* related functions in the kernel.  Other features
introduced with RFC1644 are left intact (socket layer changes,
sendmsg(2) on connection oriented protocols)  and are meant to
be reused by a simpler and less intrusive reimplemention of the
previous T/TCP functionality.

Discussed on:	-arch
2004-11-02 22:22:22 +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
Warner Losh
f36cfd49ad Remove advertising clause from University of California Regent's
license, per letter dated July 22, 1999 and email from Peter Wemm,
Alan Cox and Robert Watson.

Approved by: core, peter, alc, rwatson
2004-04-07 20:46:16 +00:00
Bruce M Simpson
88f6b0435e Shorten the name of the socket option used to enable TCP-MD5 packet
treatment.

Submitted by:	Vincent Jardin
2004-02-16 22:21:16 +00:00
Bruce M Simpson
1cfd4b5326 Initial import of RFC 2385 (TCP-MD5) digest support.
This is the first of two commits; bringing in the kernel support first.
This can be enabled by compiling a kernel with options TCP_SIGNATURE
and FAST_IPSEC.

For the uninitiated, this is a TCP option which provides for a means of
authenticating TCP sessions which came into being before IPSEC. It is
still relevant today, however, as it is used by many commercial router
vendors, particularly with BGP, and as such has become a requirement for
interconnect at many major Internet points of presence.

Several parts of the TCP and IP headers, including the segment payload,
are digested with MD5, including a shared secret. The PF_KEY interface
is used to manage the secrets using security associations in the SADB.

There is a limitation here in that as there is no way to map a TCP flow
per-port back to an SPI without polluting tcpcb or using the SPD; the
code to do the latter is unstable at this time. Therefore this code only
supports per-host keying granularity.

Whilst FAST_IPSEC is mutually exclusive with KAME IPSEC (and thus IPv6),
TCP_SIGNATURE applies only to IPv4. For the vast majority of prospective
users of this feature, this will not pose any problem.

This implementation is output-only; that is, the option is honoured when
responding to a host initiating a TCP session, but no effort is made
[yet] to authenticate inbound traffic. This is, however, sufficient to
interwork with Cisco equipment.

Tested with a Cisco 2501 running IOS 12.0(27), and Quagga 0.96.4 with
local patches. Patches for tcpdump to validate TCP-MD5 sessions are also
available from me upon request.

Sponsored by:	sentex.net
2004-02-11 04:26:04 +00:00
Andre Oppermann
bed824fa90 Disable the minmssoverload connection drop by default until the detection
logic is refined.
2004-01-12 15:46:04 +00:00
Andre Oppermann
1ddc17c1d5 Reduce TCP_MINMSS default to 216. The AX.25 protocol (packet radio)
is frequently used with an MTU of 256 because of slow speeds and a
high packet loss rate.
2004-01-09 14:14:10 +00:00
Andre Oppermann
53369ac9bb Limiters and sanity checks for TCP MSS (maximum segement size)
resource exhaustion attacks.

For network link optimization TCP can adjust its MSS and thus
packet size according to the observed path MTU.  This is done
dynamically based on feedback from the remote host and network
components along the packet path.  This information can be
abused to pretend an extremely low path MTU.

The resource exhaustion works in two ways:

 o during tcp connection setup the advertized local MSS is
   exchanged between the endpoints.  The remote endpoint can
   set this arbitrarily low (except for a minimum MTU of 64
   octets enforced in the BSD code).  When the local host is
   sending data it is forced to send many small IP packets
   instead of a large one.

   For example instead of the normal TCP payload size of 1448
   it forces TCP payload size of 12 (MTU 64) and thus we have
   a 120 times increase in workload and packets. On fast links
   this quickly saturates the local CPU and may also hit pps
   processing limites of network components along the path.

   This type of attack is particularly effective for servers
   where the attacker can download large files (WWW and FTP).

   We mitigate it by enforcing a minimum MTU settable by sysctl
   net.inet.tcp.minmss defaulting to 256 octets.

 o the local host is reveiving data on a TCP connection from
   the remote host.  The local host has no control over the
   packet size the remote host is sending.  The remote host
   may chose to do what is described in the first attack and
   send the data in packets with an TCP payload of at least
   one byte.  For each packet the tcp_input() function will
   be entered, the packet is processed and a sowakeup() is
   signalled to the connected process.

   For example an attack with 2 Mbit/s gives 4716 packets per
   second and the same amount of sowakeup()s to the process
   (and context switches).

   This type of attack is particularly effective for servers
   where the attacker can upload large amounts of data.
   Normally this is the case with WWW server where large POSTs
   can be made.

   We mitigate this by calculating the average MSS payload per
   second.  If it goes below 'net.inet.tcp.minmss' and the pps
   rate is above 'net.inet.tcp.minmssoverload' defaulting to
   1000 this particular TCP connection is resetted and dropped.

MITRE CVE:	CAN-2004-0002
Reviewed by:	sam (mentor)
MFC after:	1 day
2004-01-08 17:40:07 +00:00
Mike Barcroft
c0ec31f93e Include <sys/cdefs.h> so the visibility conditionals are available.
(This should have been included with the previous revision.)
2002-10-02 04:22:34 +00:00
Mike Barcroft
0cd4a9031e Use visibility conditionals. Only TCP_NODELAY ends up being defined
in the standards case.
2002-10-02 04:19:47 +00:00
Robert Watson
46a27060af o Minor style(9)ism to make consistent with -STABLE 2001-01-09 18:26:17 +00:00
Robert Watson
65450f2f77 o IPFW incorrectly handled filtering in the presence of previously
reserved and now allocated TCP flags in incoming packets.  This patch
  stops overloading those bits in the IP firewall rules, and moves
  colliding flags to a seperate field, ipflg.  The IPFW userland
  management tool, ipfw(8), is updated to reflect this change.  New TCP
  flags related to ECN are now included in tcp.h for reference, although
  we don't currently implement TCP+ECN.

o To use this fix without completely rebuilding, it is sufficient to copy
  ip_fw.h and tcp.h into your appropriate include directory, then rebuild
  the ipfw kernel module, and ipfw tool, and install both.  Note that a
  mismatch between module and userland tool will result in incorrect
  installation of firewall rules that may have unexpected effects.  This
  is an MFC candidate, following shakedown.  This bug does not appear
  to affect ipfilter.

Reviewed by:	security-officer, billf
Reported by:	Aragon Gouveia <aragon@phat.za.net>
2001-01-09 03:10:30 +00:00
Jonathan Lemon
46f5848237 Implement TCP NewReno, as documented in RFC 2582. This allows
better recovery for multiple packet losses in a single window.
The algorithm can be toggled via the sysctl net.inet.tcp.newreno,
which defaults to "on".

Submitted by:  Jayanth Vijayaraghavan <jayanth@yahoo-inc.com>
2000-05-06 03:31:09 +00:00
Yoshinobu Inoue
fb59c426ff tcp updates to support IPv6.
also a small patch to sys/nfs/nfs_socket.c, as max_hdr size change.

Reviewed by: freebsd-arch, cvs-committers
Obtained from: KAME project
2000-01-09 19:17:30 +00:00
Yoshinobu Inoue
76429de41a KAME related header files additions and merges.
(only those which don't affect c source files so much)

Reviewed by: cvs-committers
Obtained from: KAME project
1999-11-05 14:41:39 +00:00
Peter Wemm
c3aac50f28 $Id$ -> $FreeBSD$ 1999-08-28 01:08:13 +00:00
Bruce Evans
07a4df4fee Declare tcp_seq and tcp_cc as fixed-size types. Half fixed type
mismatches exposed by this (the prototype for tcp_respond() didn't
match the  function definition lexically, and still depends on a
gcc feature to match if ints have more than 32 bits).
1998-07-13 11:09:52 +00:00
Bruce Evans
a09bee1aa8 Fixed pedantic semantics errors (bitfields not of type int, signed int
or unsigned int (this doesn't change the struct layout, size or
alignment in any of the files changed in this commit, at least for
gcc on i386's.  Using bitfields of type u_char may affect size and
alignment but not packing)).
1998-06-08 09:47:47 +00:00
Peter Wemm
6875d25465 Back out part 1 of the MCFH that changed $Id$ to $FreeBSD$. We are not
ready for it yet.
1997-02-22 09:48:43 +00:00
Jordan K. Hubbard
1130b656e5 Make the long-awaited change from $Id$ to $FreeBSD$
This will make a number of things easier in the future, as well as (finally!)
avoiding the Id-smashing problem which has plagued developers for so long.

Boy, I'm glad we're not using sup anymore.  This update would have been
insane otherwise.
1997-01-14 07:20:47 +00:00
Rodney W. Grimes
9b2e535452 Remove trailing whitespace. 1995-05-30 08:16:23 +00:00
Garrett Wollman
2f96f1f446 Get rid of some unneeded #ifdef TTCP lines. Also, get rid of some
bogus commons declared in header files.
1995-02-14 02:35:19 +00:00
Garrett Wollman
eb6ad69646 Merge in T/TCP TCP header file changes. 1995-02-08 20:18:48 +00:00
Paul Richards
707f139edb Made idempotent.
Submitted by:	Paul
1994-08-21 05:27:42 +00:00
David Greenman
3c4dd3568f Added $Id$ 1994-08-02 07:55:43 +00:00
Rodney W. Grimes
df8bae1de4 BSD 4.4 Lite Kernel Sources 1994-05-24 10:09:53 +00:00