Commit Graph

185 Commits

Author SHA1 Message Date
Bjoern A. Zeeb
82cea7e6f3 MFP4: @176978-176982, 176984, 176990-176994, 177441
"Whitspace" churn after the VIMAGE/VNET whirls.

Remove the need for some "init" functions within the network
stack, like pim6_init(), icmp_init() or significantly shorten
others like ip6_init() and nd6_init(), using static initialization
again where possible and formerly missed.

Move (most) variables back to the place they used to be before the
container structs and VIMAGE_GLOABLS (before r185088) and try to
reduce the diff to stable/7 and earlier as good as possible,
to help out-of-tree consumers to update from 6.x or 7.x to 8 or 9.

This also removes some header file pollution for putatively
static global variables.

Revert VIMAGE specific changes in ipfilter::ip_auth.c, that are
no longer needed.

Reviewed by:	jhb
Discussed with:	rwatson
Sponsored by:	The FreeBSD Foundation
Sponsored by:	CK Software GmbH
MFC after:	6 days
2010-04-29 11:52:42 +00:00
Bjoern A. Zeeb
376aadf896 Destroy TCP UMA zones (empty or not) upon network stack teardown
to not leak them, otherwise making UMA/vmstat unhappy with every stoped vnet.
We will still leak pages (especially for zones marked NOFREE).

Reshuffle cleanup order in tcp_destroy() to get rid of what we can
easily free first.

Sponsored by:	ISPsystem
Reviewed by:	rwatson
MFC after:	5 days
2010-03-07 15:58:44 +00:00
Bjoern A. Zeeb
4dcc55a363 Garbage collect references to the no longer implemented tcp_fasttimo().
Discussed with:	rwatson
MFC after:	5 days
2010-01-17 13:07:52 +00:00
Mike Silbersack
b8614722ff Add the ability to see TCP timers via netstat -x. This can be a useful
feature when you have a seemingly stuck socket and want to figure
out why it has not been closed yet.

No plans to MFC this, as it changes the netstat sysctl ABI.

Reviewed by:	andre, rwatson, Eric Van Gyzen
2009-09-16 05:33:15 +00:00
Robert Watson
315e3e38fa Many network stack subsystems use a single global data structure to hold
all pertinent statatistics for the subsystem.  These structures are
sometimes "borrowed" by kernel modules that require a place to store
statistics for similar events.

Add KPI accessor functions for statistics structures referenced by kernel
modules so that they no longer encode certain specifics of how the data
structures are named and stored.  This change is intended to make it
easier to move to per-CPU network stats following 8.0-RELEASE.

The following modules are affected by this change:

      if_bridge
      if_cxgb
      if_gif
      ip_mroute
      ipdivert
      pf

In practice, most of these statistics consumers should, in fact, maintain
their own statistics data structures rather than borrowing structures
from the base network stack.  However, that change is too agressive for
this point in the release cycle.

Reviewed by:	bz
Approved by:	re (kib)
2009-08-02 19:43:32 +00:00
Robert Watson
1e77c1056a Remove unused VNET_SET() and related macros; only VNET_GET() is
ever actually used.  Rename VNET_GET() to VNET() to shorten
variable references.

Discussed with:	bz, julian
Reviewed by:	bz
Approved by:	re (kensmith, kib)
2009-07-16 21:13:04 +00:00
Robert Watson
eddfbb763d Build on Jeff Roberson's linker-set based dynamic per-CPU allocator
(DPCPU), as suggested by Peter Wemm, and implement a new per-virtual
network stack memory allocator.  Modify vnet to use the allocator
instead of monolithic global container structures (vinet, ...).  This
change solves many binary compatibility problems associated with
VIMAGE, and restores ELF symbols for virtualized global variables.

Each virtualized global variable exists as a "reference copy", and also
once per virtual network stack.  Virtualized global variables are
tagged at compile-time, placing the in a special linker set, which is
loaded into a contiguous region of kernel memory.  Virtualized global
variables in the base kernel are linked as normal, but those in modules
are copied and relocated to a reserved portion of the kernel's vnet
region with the help of a the kernel linker.

Virtualized global variables exist in per-vnet memory set up when the
network stack instance is created, and are initialized statically from
the reference copy.  Run-time access occurs via an accessor macro, which
converts from the current vnet and requested symbol to a per-vnet
address.  When "options VIMAGE" is not compiled into the kernel, normal
global ELF symbols will be used instead and indirection is avoided.

This change restores static initialization for network stack global
variables, restores support for non-global symbols and types, eliminates
the need for many subsystem constructors, eliminates large per-subsystem
structures that caused many binary compatibility issues both for
monitoring applications (netstat) and kernel modules, removes the
per-function INIT_VNET_*() macros throughout the stack, eliminates the
need for vnet_symmap ksym(2) munging, and eliminates duplicate
definitions of virtualized globals under VIMAGE_GLOBALS.

Bump __FreeBSD_version and update UPDATING.

Portions submitted by:  bz
Reviewed by:            bz, zec
Discussed with:         gnn, jamie, jeff, jhb, julian, sam
Suggested by:           peter
Approved by:            re (kensmith)
2009-07-14 22:48:30 +00:00
Lawrence Stewart
237fbe0a1c Replace struct tcpopt with a proxy toeopt struct in the TOE driver interface to
the TCP syncache. This returns struct tcpopt to being private within the TCP
implementation, thus allowing it to be modified without ABI concerns.

The patch breaks the ABI. Bump __FreeBSD_version to 800103 accordingly. The cxgb
driver is the only TOE consumer affected by this change, and needs to be
recompiled along with the kernel.

Suggested by:	rwatson
Reviewed by:	rwatson, kmacy
Approved by:	re (kensmith), kensmith (mentor temporarily unavailable)
2009-07-13 11:51:02 +00:00
Lawrence Stewart
962ebef8c0 Pad the following TCP related structs to allow MFCs of upcoming features/fixes
back to the 8 branch:

tcp_var.h
- struct sackhint
- struct tcpcb
- struct tcpstat

The patch breaks the ABI. Bump __FreeBSD_version to 800102 accordingly. User
space tools that rely on the size of any of these structs (e.g. sockstat) need
to be recompiled.

Reviewed by:	rpaulo, sam, andre, rwatson
Approved by:	re & mentor (gnn)
2009-07-12 09:14:28 +00:00
John Baldwin
9f78a87a06 - Change members of tcpcb that cache values of ticks from int to u_int:
t_rcvtime, t_starttime, t_rtttime, t_bw_rtttime, ts_recent_age,
  t_badrxtwin.
- Change t_recent in struct timewait from u_long to u_int32_t to match
  the type of the field it shadows from tcpcb: ts_recent.
- Change t_starttime in struct timewait from u_long to u_int to match
  the t_starttime field in tcpcb.

Requested by:	bde (1, 3)
2009-06-16 18:58:50 +00:00
John Baldwin
0e8cc7e748 Change a few members of tcpcb that store cached copies of ticks to be ints
instead of unsigned longs.  This fixes a few overflow edge cases on 64-bit
platforms.  Specifically, if an idle connection receives a packet shortly
before 2^31 clock ticks of uptime (about 25 days with hz=1000) and the keep
alive timer fires after 2^31 clock ticks, the keep alive timer will think
that the connection has been idle for a very long time and will immediately
drop the connection instead of sending a keep alive probe.

Reviewed by:	silby, gnn, lstewart
MFC after:	1 week
2009-06-10 18:27:15 +00:00
Marko Zec
bc29160df3 Introduce an infrastructure for dismantling vnet instances.
Vnet modules and protocol domains may now register destructor
functions to clean up and release per-module state.  The destructor
mechanisms can be triggered by invoking "vimage -d", or a future
equivalent command which will be provided via the new jail framework.

While this patch introduces numerous placeholder destructor functions,
many of those are currently incomplete, thus leaking memory or (even
worse) failing to stop all running timers.  Many of such issues are
already known and will be incrementaly fixed over the next weeks in
smaller incremental commits.

Apart from introducing new fields in structs ifnet, domain, protosw
and vnet_net, which requires the kernel and modules to be rebuilt, this
change should have no impact on nooptions VIMAGE builds, since vnet
destructors can only be called in VIMAGE kernels.  Moreover,
destructor functions should be in general compiled in only in
options VIMAGE builds, except for kernel modules which can be safely
kldunloaded at run time.

Bump __FreeBSD_version to 800097.
Reviewed by:	bz, julian
Approved by:	rwatson, kib (re), julian (mentor)
2009-06-08 17:15:40 +00:00
Marko Zec
f6dfe47a14 Permit buiding kernels with options VIMAGE, restricted to only a single
active network stack instance.  Turning on options VIMAGE at compile
time yields the following changes relative to default kernel build:

1) V_ accessor macros for virtualized variables resolve to structure
fields via base pointers, instead of being resolved as fields in global
structs or plain global variables.  As an example, V_ifnet becomes:

    options VIMAGE:          ((struct vnet_net *) vnet_net)->_ifnet
    default build:           vnet_net_0._ifnet
    options VIMAGE_GLOBALS:  ifnet

2) INIT_VNET_* macros will declare and set up base pointers to be used
by V_ accessor macros, instead of resolving to whitespace:

    INIT_VNET_NET(ifp->if_vnet); becomes

    struct vnet_net *vnet_net = (ifp->if_vnet)->mod_data[VNET_MOD_NET];

3) Memory for vnet modules registered via vnet_mod_register() is now
allocated at run time in sys/kern/kern_vimage.c, instead of per vnet
module structs being declared as globals.  If required, vnet modules
can now request the framework to provide them with allocated bzeroed
memory by filling in the vmi_size field in their vmi_modinfo structures.

4) structs socket, ifnet, inpcbinfo, tcpcb and syncache_head are
extended to hold a pointer to the parent vnet.  options VIMAGE builds
will fill in those fields as required.

5) curvnet is introduced as a new global variable in options VIMAGE
builds, always pointing to the default and only struct vnet.

6) struct sysctl_oid has been extended with additional two fields to
store major and minor virtualization module identifiers, oid_v_subs and
oid_v_mod.  SYSCTL_V_* family of macros will fill in those fields
accordingly, and store the offset in the appropriate vnet container
struct in oid_arg1.
In sysctl handlers dealing with virtualized sysctls, the
SYSCTL_RESOLVE_V_ARG1() macro will compute the address of the target
variable and make it available in arg1 variable for further processing.

Unused fields in structs vnet_inet, vnet_inet6 and vnet_ipfw have
been deleted.

Reviewed by:	bz, rwatson
Approved by:	julian (mentor)
2009-04-30 13:36:26 +00:00
Robert Watson
de231a063a Put TCPSTAT_ADD() and TCPSTAT_INC() behind _KERNEL.
MFC after:	3 days
2009-04-12 21:28:35 +00:00
Robert Watson
78b5071407 Update stats in struct tcpstat using two new macros, TCPSTAT_ADD() and
TCPSTAT_INC(), rather than directly manipulating the fields across the
kernel.  This will make it easier to change the implementation of
these statistics, such as using per-CPU versions of the data structures.

MFC after:	3 days
2009-04-11 22:07:19 +00:00
Bjoern A. Zeeb
de4fbddd5b Add externs to fix build with VIMAGE_GLOBALS after r187289. 2009-01-22 10:29:09 +00:00
Lawrence Stewart
24cb0f2232 Add TCP Appropriate Byte Counting (RFC 3465) support to kernel.
The new behaviour is on by default, and can be disabled by setting the
net.inet.tcp.rfc3465 sysctl to 0 to obtain previous behaviour.

The patch changes struct tcpcb in sys/netinet/tcp_var.h which breaks
the ABI. Bump __FreeBSD_version to 800061 accordingly. User space tools
that rely on the size of struct tcpcb (e.g. sockstat) need to be recompiled.

Reviewed by:	rpaulo, gnn
Approved by:	gnn, kmacy (mentors)
Sponsored by:	FreeBSD Foundation
2009-01-15 06:44:22 +00:00
Bjoern A. Zeeb
1b193af610 Second round of putting global variables, which were virtualized
but formerly missed under VIMAGE_GLOBAL.

Put the extern declarations of the  virtualized globals
under VIMAGE_GLOBAL as the globals themsevles are already.
This will help by the time when we are going to remove the globals
entirely.

Sponsored by:	The FreeBSD Foundation
2008-12-13 19:13:03 +00:00
Bjoern A. Zeeb
86413abf5f Put a global variables, which were virtualized but formerly
missed under VIMAGE_GLOBAL.

Start putting the extern declarations of the  virtualized globals
under VIMAGE_GLOBAL as the globals themsevles are already.
This will help by the time when we are going to remove the globals
entirely.

While there garbage collect a few dead externs from ip6_var.h.

Sponsored by:	The FreeBSD Foundation
2008-12-11 16:26:38 +00:00
Robert Watson
c3ce7a790c Move flag definitions for t_flags and t_oobflags below the definition of
struct tcpcb so that the structure definition is a bit more vertically
compact.  Can't yet fit it on one printed page, though.

MFC after:	pretty soon
2008-12-10 11:03:16 +00:00
Marko Zec
44e33a0758 Change the initialization methodology for global variables scheduled
for virtualization.

Instead of initializing the affected global variables at instatiation,
assign initial values to them in initializer functions.  As a rule,
initialization at instatiation for such variables should never be
introduced again from now on.  Furthermore, enclose all instantiations
of such global variables in #ifdef VIMAGE_GLOBALS blocks.

Essentialy, this change should have zero functional impact.  In the next
phase of merging network stack virtualization infrastructure from
p4/vimage branch, the new initialization methology will allow us to
switch between using global variables and their counterparts residing in
virtualization containers with minimum code churn, and in the long run
allow us to intialize multiple instances of such container structures.

Discussed at:	devsummit Strassburg
Reviewed by:	bz, julian
Approved by:	julian (mentor)
Obtained from:	//depot/projects/vimage-commit2/...
X-MFC after:	never
Sponsored by:	NLnet Foundation, The FreeBSD Foundation
2008-11-19 09:39:34 +00:00
Bjoern A. Zeeb
91d6cfa6b1 Fix a bug introduced with r182851 splitting tcp_mss() into
tcp_mss() and tcp_mss_update() so that tcp_mtudisc() could
re-use the same code.

Move the TSO logic back to tcp_mss() and out of tcp_mss_update().
We tried to avoid that initially but if were are called from
tcp_output() with EMSGSIZE, we cleared the TSO flag on the tcpcb
there, called into tcp_mtudisc() and tcp_mss_update() which
then would reenable TSO on the tcpcb based on TSO capabilities
of the interface as learnt in tcp_maxmtu/6().
So if TSO was enabled on the (possibly new) outgoing interface
it was turned back on, which lead to an endless loop between
tcp_output() and tcp_mtudisc() until we overflew the stack.

Reported by:	kmacy
MFC after:	2 months (along with r182851)
2008-11-06 13:25:59 +00:00
Bjoern A. Zeeb
3cee92e074 Split tcp_mss() in tcp_mss() and tcp_mss_update() where the former
calls the latter.

Merge tcp_mss_update() with code from tcp_mtudisc() basically
doing the same thing.

This gives us one central place where we calcuate and check mss values
to update t_maxopd (maximum mss + options length) instead of two slightly
different but almost equal implementations to maintain.

PR:		kern/118455
Reviewed by:	silby (back in March)
MFC after:	2 months
2008-09-07 18:50:25 +00:00
Rui Paulo
f2512ba12a MFp4 (//depot/projects/tcpecn/):
TCP ECN support. Merge of my GSoC 2006 work for NetBSD.
  TCP ECN is defined in RFC 3168.

Partly reviewed by:	dwmalone, silby
Obtained from:		NetBSD
2008-07-31 15:10:09 +00:00
Bjoern A. Zeeb
032fae41d4 Revert to rev. 1.161 - switch back to optimized TCP options ordering.
A lot of testing has shown that the problem people were seeing was due
to invalid padding after the end of option list option, which was corrected
in tcp_output.c rev. 1.146.

Thanks to:		anders@, s3raphi, Matt Reimer
Thanks to:		Doug Hardie and Randy Rose, John Mayer, Susan Guzzardi
Special thanks to:	dwhite@ and BitGravity
Discussed with:		silby
MFC after:		1 day
2008-04-20 18:36:59 +00:00
Mike Silbersack
ea346b19cc Change FreeBSD 7 so that it returns TCP options in
the same order that FreeBSD 6 and before did.  Doug
White and the other bloodhounds at ISC discovered that
while FreeBSD 7's ordering of options was more efficient,
it caused some cable modem routers to ignore the
SYN-ACKs ordered in this fashion.

The placement of sackOK after the timestamp option seems
to be the critical difference:

FreeBSD 6:
<mss 1460,nop,wscale 1,nop,nop,timestamp 3512155768 0,sackOK,eol>

FreeBSD 7.0:
<mss 1460,nop,wscale 3,sackOK,timestamp 1370692577 0>

FreeBSD 7.0 + this change:
<mss 1460,nop,wscale 3,nop,nop,timestamp 7371813 0,sackOK,eol>

MFC after: 1 week
2008-02-24 05:13:20 +00:00
Kip Macy
76b262c426 Fix style issues with initial TCP offload commit
Requested by: rwatson
Submitted by: rwatson
2007-12-12 23:31:49 +00:00
Kip Macy
620721db82 Add driver independent interface to offload active established TCP connections
Reviewed by: silby
2007-12-12 20:21:39 +00:00
Kip Macy
2de2af32a0 Add padding for anticipated functionality
- vimage
 - TOE
 - multiq
 - host rtentry caching

Rename spare used by 80211 to if_llsoftc

Reviewed by: rwatson, gnn
MFC after: 1 day
2007-12-07 01:46:13 +00:00
Mike Silbersack
e2f2059f68 Two changes:
- Reintegrate the ANSI C function declaration change
  from tcp_timer.c rev 1.92

- Reorganize the tcpcb structure so that it has a single
  pointer to the "tcp_timer" structure which contains all
  of the tcp timer callouts.  This change means that when
  the single tcp timer change is reintegrated, tcpcb will
  not change in size, and therefore the ABI between
  netstat and the kernel will not change.

Neither of these changes should have any functional
impact.

Reviewed by: bmah, rrs
Approved by: re (bmah)
2007-09-24 05:26:24 +00:00
Robert Watson
85d9437250 Back out tcp_timer.c:1.93 and associated changes that reimplemented the many
TCP timers as a single timer, but retain the API changes necessary to
reintroduce this change.  This will back out the source of at least two
reported problems: lock leaks in certain timer edge cases, and TCP timers
continuing to fire after a connection has closed (a bug previously fixed and
then reintroduced with the timer rewrite).

In a follow-up commit, some minor restylings and comment changes performed
after the TCP timer rewrite will be reapplied, and a further change to allow
the TCP timer rewrite to be added back without disturbing the ABI.  The new
design is believed to be a good thing, but the outstanding issues are
leading to significant stability/correctness problems that are holding
up 7.0.

This patch was generated by silby, but is being committed by proxy due to
poor network connectivity for silby this week.

Approved by:	re (kensmith)
Submitted by:	silby
Tested by:	rwatson, kris
Problems reported by:	peter, kris, others
2007-09-07 09:19:22 +00:00
Andre Oppermann
773673c133 Provide a sysctl to toggle reporting of TCP debug logging:
sys.net.inet.tcp.log_debug = 1

It defaults to enabled for the moment and is to be turned off for
the next release like other diagnostics from development branches.

It is important to note that sysctl sys.net.inet.tcp.log_in_vain
uses the same logging function as log_debug.  Enabling of the former
also causes the latter to engage, but not vice versa.

Use consistent terminology in tcp log messages:

 "ignored" means a segment contains invalid flags/information and
   is dropped without changing state or issuing a reply.

 "rejected" means a segments contains invalid flags/information but
   is causing a reply (usually RST) and may cause a state change.

Approved by:	re (rwatson)
2007-07-28 12:20:39 +00:00
Mike Silbersack
c325962b47 Export the contents of the syncache to netstat.
Approved by: re (kensmith)
MFC after: 2 weeks
2007-07-27 00:57:06 +00:00
Peter Wemm
9fb5d4c064 Fix cast-qualifiers warning when INET6 is not present
Approved by:  re (rwatson)
2007-07-05 05:55:57 +00:00
Andre Oppermann
a160e6302c Refactor and rewrite in parts the SYN handling code on listen sockets
in tcp_input():

 o tighten the checks on allowed TCP flags to be RFC793 and
   tcp-secure conform
 o log check failures to syslog at LOG_DEBUG level
 o rearrange the code flow to be easier to follow
 o add KASSERTs to validate assumptions of the code flow

Add sysctl net.inet.tcp.syncache.rst_on_sock_fail defaulting to enable
that controls the behavior on socket creation failure for a otherwise
successful 3-way handshake.  The socket creation can fail due to global
memory shortage, listen queue limits and file descriptor limits.  The
sysctl allows to chose between two options to deal with this.  One is
to send a reset to the other endpoint to notify it about the failure
(default).  The other one is to ignore and treat the failure as a
transient error and have the other endpoint retransmit for another try.

Reviewed by:	rwatson (in general)
2007-05-28 11:03:53 +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
2104448fe7 Move TIME_WAIT related functions and timer handling from files
other than repo copied tcp_subr.c into tcp_timewait.c#1.284:

 tcp_input.c#1.350 tcp_timewait() -> tcp_twcheck()

 tcp_timer.c#1.92 tcp_timer_2msl_reset() -> tcp_tw_2msl_reset()
 tcp_timer.c#1.92 tcp_timer_2msl_stop() -> tcp_tw_2msl_stop()
 tcp_timer.c#1.92 tcp_timer_2msl_tw() -> tcp_tw_2msl_scan()

This is a mechanical move with appropriate renames and making
them static if used only locally.

The tcp_tw_2msl_scan() cleanup function is still run from the
tcp_slowtimo() in tcp_timer.c.
2007-05-16 17:14:25 +00:00
Andre Oppermann
ec9c755352 Complete the (mechanical) move of the TCP reassembly and timewait
functions from their origininal place to their own files.

TCP Reassembly from tcp_input.c -> tcp_reass.c
TCP Timewait   from tcp_subr.c  -> tcp_timewait.c
2007-05-13 22:16:13 +00:00
Andre Oppermann
504abdc6e6 Add the timestamp offset to struct tcptw so we can generate proper
ACKs in TIME_WAIT state that don't get dropped by the PAWS check
on the receiver.
2007-05-11 18:29:39 +00:00
Andre Oppermann
1a5537409f Remove unused requested_s_scale from struct tcpcb. 2007-05-06 16:04:36 +00:00
Andre Oppermann
3529149e9a Use existing TF_SACK_PERMIT flag in struct tcpcb t_flags field instead of
a decdicated sack_enable int for this bool.  Change all users accordingly.
2007-05-06 15:56:31 +00:00
Robert Watson
6087c3c29e Add global mutex tcp_debug_mtx, which will protect global TCP debugging
state tcp_debug, tcp_debx.  Acquire and drop as required in tcp_trace().

Move to ANSI C function header, correct prototype types so that short TCP
state is no longer promoted to int unnecessarily.

Add comments.

MFC after:	3 weeks
2007-05-04 23:43:18 +00:00
Andre Oppermann
df47e4377b o Remove unncessary TOF_SIGLEN flag from struct tcpopt
o Correctly set to->to_signature in tcp_dooptions()
o Update comments
2007-04-20 15:28:01 +00:00
Andre Oppermann
4d6e713043 Remove bogus check for accept queue length and associated failure handling
from the incoming SYN handling section of tcp_input().

Enforcement of the accept queue limits is done by sonewconn() after the
3WHS is completed.  It is not necessary to have an earlier check before a
connection request enters the SYN cache awaiting the full handshake.  It
rather limits the effectiveness of the syncache by preventing legit and
illegit connections from entering it and having them shaken out before we
hit the real limit which may have vanished by then.

Change return value of syncache_add() to void.  No status communication
is required.
2007-04-20 14:34:54 +00:00
Andre Oppermann
b8152ba793 Change the TCP timer system from using the callout system five times
directly to a merged model where only one callout, the next to fire,
is registered.

Instead of callout_reset(9) and callout_stop(9) the new function
tcp_timer_activate() is used which then internally manages the callout.

The single new callout is a mutex callout on inpcb simplifying the
locking a bit.

tcp_timer() is the called function which handles all race conditions
in one place and then dispatches the individual timer functions.

Reviewed by:	rwatson (earlier version)
2007-04-11 09:45:16 +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
Mohan Srinivasan
7c72af8770 Reap FIN_WAIT_2 connections marked SOCANTRCVMORE faster. This mitigate
potential issues where the peer does not close, potentially leaving
thousands of connections in FIN_WAIT_2. This is controlled by a new sysctl
fast_finwait2_recycle, which is disabled by default.

Reviewed by: gnn, silby.
2007-02-26 22:25:21 +00:00
Andre Oppermann
6741ecf595 Auto sizing TCP socket buffers.
Normally the socket buffers are static (either derived from global
defaults or set with setsockopt) and do not adapt to real network
conditions. Two things happen: a) your socket buffers are too small
and you can't reach the full potential of the network between both
hosts; b) your socket buffers are too big and you waste a lot of
kernel memory for data just sitting around.

With automatic TCP send and receive socket buffers we can start with a
small buffer and quickly grow it in parallel with the TCP congestion
window to match real network conditions.

FreeBSD has a default 32K send socket buffer. This supports a maximal
transfer rate of only slightly more than 2Mbit/s on a 100ms RTT
trans-continental link. Or at 200ms just above 1Mbit/s. With TCP send
buffer auto scaling and the default values below it supports 20Mbit/s
at 100ms and 10Mbit/s at 200ms. That's an improvement of factor 10, or
1000%. For the receive side it looks slightly better with a default of
64K buffer size.

New sysctls are:
  net.inet.tcp.sendbuf_auto=1 (enabled)
  net.inet.tcp.sendbuf_inc=8192 (8K, step size)
  net.inet.tcp.sendbuf_max=262144 (256K, growth limit)
  net.inet.tcp.recvbuf_auto=1 (enabled)
  net.inet.tcp.recvbuf_inc=16384 (16K, step size)
  net.inet.tcp.recvbuf_max=262144 (256K, growth limit)

Tested by:	many (on HEAD and RELENG_6)
Approved by:	re
MFC after:	1 month
2007-02-01 18:32:13 +00:00
Andre Oppermann
bf6d304ab2 Rewrite of TCP syncookies to remove locking requirements and to enhance
functionality:

 - Remove a rwlock aquisition/release per generated syncookie.  Locking
   is now integrated with the bucket row locking of syncache itself and
   syncookies no longer add any additional lock overhead.
 - Syncookie secrets are different for and stored per syncache buck row.
   Secrets expire after 16 seconds and are reseeded on-demand.
 - The computational overhead for syncookie generation and verification
   is one MD5 hash computation as before.
 - Syncache can be turned off and run with syncookies only by setting the
   sysctl net.inet.tcp.syncookies_only=1.

This implementation extends the orginal idea and first implementation
of FreeBSD by using not only the initial sequence number field to store
information but also the timestamp field if present.  This way we can
keep track of the entire state we need to know to recreate the session in
its original form.  Almost all TCP speakers implement RFC1323 timestamps
these days.  For those that do not we still have to live with the known
shortcomings of the ISN only SYN cookies.  The use of the timestamp field
causes the timestamps to be randomized if syncookies are enabled.

The idea of SYN cookies is to encode and include all necessary information
about the connection setup state within the SYN-ACK we send back and thus
to get along without keeping any local state until the ACK to the SYN-ACK
arrives (if ever).  Everything we need to know should be available from
the information we encoded in the SYN-ACK.

A detailed description of the inner working of the syncookies mechanism
is included in the comments in tcp_syncache.c.

Reviewed by:	silby (slightly earlier version)
Sponsored by:	TCP/IP Optimization Fundraise 2005
2006-09-13 13:08:27 +00:00