Commit Graph

285 Commits

Author SHA1 Message Date
Michael Tuexen
20a6a3a7a7 When sending IPv4 packets on a SOCK_RAW socket using the IP_HDRINCL option,
ensure that the ip_hl field is valid. Furthermore, ensure that the complete
IPv4 header is contained in the first mbuf. Finally, move the length checks
before relying on them when accessing fields of the IPv4 header.
Reported by:		jtl@
Reviewed by:		jtl@
MFC after:		1 week
Differential Revision:	https://reviews.freebsd.org/D19181
2019-04-13 10:47:47 +00:00
Gleb Smirnoff
dc0fa4f712 Remove 'dir' argument from dummynet_io(). This makes it possible to make
dn_dir flags private to dummynet. There is still some room for improvement.
2019-03-14 22:32:50 +00:00
Gleb Smirnoff
cef9f220cd Remove 'dir' argument in ng_ipfw_input, since ip_fw_args now has this info.
While here make 'tee' boolean.
2019-03-14 22:30:05 +00:00
Gleb Smirnoff
1830dae3d3 Make second argument of ip_divert(), that specifies packet direction a bool.
This allows pf(4) to avoid including ipfw(4) private files.
2019-03-14 22:23:09 +00:00
Michael Tuexen
aef0641755 Improve input validation for raw IPv4 socket using the IP_HDRINCL
option.

This issue was found by running syzkaller on OpenBSD.
Greg Steuck made me aware that the problem might also exist on FreeBSD.

Reported by:		Greg Steuck
MFC after:		1 month
Differential Revision:	https://reviews.freebsd.org/D18834
2019-02-12 10:17:21 +00:00
Mark Johnston
79db6fe7aa Plug some networking sysctl leaks.
Various network protocol sysctl handlers were not zero-filling their
output buffers and thus would export uninitialized stack memory to
userland.  Fix a number of such handlers.

Reported by:	Thomas Barabosch, Fraunhofer FKIE
Reviewed by:	tuexen
MFC after:	3 days
Security:	kernel memory disclosure
Sponsored by:	The FreeBSD Foundation
Differential Revision:	https://reviews.freebsd.org/D18301
2018-11-22 20:49:41 +00:00
Steven Hartland
65c3a353e6 Removed pointless NULL check
Removed pointless NULL check after malloc with M_WAITOK which can never
return NULL.

Sponsored by:	Multiplay
2018-07-10 08:05:32 +00:00
Matt Macy
6573d7580b epoch(9): allow preemptible epochs to compose
- Add tracker argument to preemptible epochs
- Inline epoch read path in kernel and tied modules
- Change in_epoch to take an epoch as argument
- Simplify tfb_tcp_do_segment to not take a ti_locked argument,
  there's no longer any benefit to dropping the pcbinfo lock
  and trying to do so just adds an error prone branchfest to
  these functions
- Remove cases of same function recursion on the epoch as
  recursing is no longer free.
- Remove the the TAILQ_ENTRY and epoch_section from struct
  thread as the tracker field is now stack or heap allocated
  as appropriate.

Tested by: pho and Limelight Networks
Reviewed by: kbowling at llnw dot com
Sponsored by: Limelight Networks
Differential Revision: https://reviews.freebsd.org/D16066
2018-07-04 02:47:16 +00:00
Matt Macy
99208b820f inpcb: don't gratuitously defer frees
Don't defer frees in sysctl handlers. It isn't necessary
and it just confuses things.
revert: r333911, r334104, and r334125

Requested by: jtl
2018-07-02 05:19:44 +00:00
Matt Macy
e93fdbe212 raw_ip: validate inp in both loops
Continuation of r335497. Also move the lock acquisition up to
validate before referencing inp_cred.

Reported by:	pho
2018-06-21 20:18:23 +00:00
Matt Macy
e5c331cf78 raw_ip: validate inp
Post r335356 it is possible to have an inpcb on the hash lists that is
partially torn down. Validate before using.

Reported by:	pho
2018-06-21 17:24:10 +00:00
Matt Macy
b872626dbe mechanical CK macro conversion of inpcbinfo lists
This is a dependency for converting the inpcbinfo hash and info rlocks
to epoch.
2018-06-12 22:18:20 +00:00
Matt Macy
fe524329e4 convert allocations to INVARIANTS M_ZERO 2018-05-24 01:04:56 +00:00
Matt Macy
4f6c66cc9c UDP: further performance improvements on tx
Cumulative throughput while running 64
  netperf -H $DUT -t UDP_STREAM -- -m 1
on a 2x8x2 SKL went from 1.1Mpps to 2.5Mpps

Single stream throughput increases from 910kpps to 1.18Mpps

Baseline:
https://people.freebsd.org/~mmacy/2018.05.11/udpsender2.svg

- Protect read access to global ifnet list with epoch
https://people.freebsd.org/~mmacy/2018.05.11/udpsender3.svg

- Protect short lived ifaddr references with epoch
https://people.freebsd.org/~mmacy/2018.05.11/udpsender4.svg

- Convert if_afdata read lock path to epoch
https://people.freebsd.org/~mmacy/2018.05.11/udpsender5.svg

A fix for the inpcbhash contention is pending sufficient time
on a canary at LLNW.

Reviewed by:	gallatin
Sponsored by:	Limelight Networks
Differential Revision:	https://reviews.freebsd.org/D15409
2018-05-23 21:02:14 +00:00
Matt Macy
246a619924 epoch: allow for conditionally asserting that the epoch context fields
are unused by zeroing on INVARIANTS builds
2018-05-23 17:00:05 +00:00
Matt Macy
056b40e29c inpcb: consolidate possible deletion in pcblist functions in to epoch
deferred context.
2018-05-20 02:27:58 +00:00
Matt Macy
d7c5a620e2 ifnet: Replace if_addr_lock rwlock with epoch + mutex
Run on LLNW canaries and tested by pho@

gallatin:
Using a 14-core, 28-HTT single socket E5-2697 v3 with a 40GbE MLX5
based ConnectX 4-LX NIC, I see an almost 12% improvement in received
packet rate, and a larger improvement in bytes delivered all the way
to userspace.

When the host receiving 64 streams of netperf -H $DUT -t UDP_STREAM -- -m 1,
I see, using nstat -I mce0 1 before the patch:

InMpps OMpps  InGbs  OGbs err TCP Est %CPU syscalls csw     irq GBfree
4.98   0.00   4.42   0.00 4235592     33   83.80 4720653 2149771   1235 247.32
4.73   0.00   4.20   0.00 4025260     33   82.99 4724900 2139833   1204 247.32
4.72   0.00   4.20   0.00 4035252     33   82.14 4719162 2132023   1264 247.32
4.71   0.00   4.21   0.00 4073206     33   83.68 4744973 2123317   1347 247.32
4.72   0.00   4.21   0.00 4061118     33   80.82 4713615 2188091   1490 247.32
4.72   0.00   4.21   0.00 4051675     33   85.29 4727399 2109011   1205 247.32
4.73   0.00   4.21   0.00 4039056     33   84.65 4724735 2102603   1053 247.32

After the patch

InMpps OMpps  InGbs  OGbs err TCP Est %CPU syscalls csw     irq GBfree
5.43   0.00   4.20   0.00 3313143     33   84.96 5434214 1900162   2656 245.51
5.43   0.00   4.20   0.00 3308527     33   85.24 5439695 1809382   2521 245.51
5.42   0.00   4.19   0.00 3316778     33   87.54 5416028 1805835   2256 245.51
5.42   0.00   4.19   0.00 3317673     33   90.44 5426044 1763056   2332 245.51
5.42   0.00   4.19   0.00 3314839     33   88.11 5435732 1792218   2499 245.52
5.44   0.00   4.19   0.00 3293228     33   91.84 5426301 1668597   2121 245.52

Similarly, netperf reports 230Mb/s before the patch, and 270Mb/s after the patch

Reviewed by:	gallatin
Sponsored by:	Limelight Networks
Differential Revision:	https://reviews.freebsd.org/D15366
2018-05-18 20:13:34 +00:00
Sean Bruno
72bfa0bf63 Revert r331379 as the "simple" lock changes have revealed a deeper problem
and need for a rethink.

Submitted by:	Jason Eggleston <jason@eggnet.com>
Sponsored by:	Limelight Networks
2018-03-23 18:34:38 +00:00
Sean Bruno
2a499acf59 Simple locking fixes in ip_ctloutput, ip6_ctloutput, rip_ctloutput.
Submitted by:	Jason Eggleston <jason@eggnet.com>
Sponsored by:	Limelight Networks
Differential Revision:	https://reviews.freebsd.org/D14624
2018-03-22 22:29:32 +00:00
Pedro F. Giffuni
51369649b0 sys: further adoption of SPDX licensing ID tags.
Mainly focus on files that use BSD 3-Clause license.

The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.

Special thanks to Wind River for providing access to "The Duke of
Highlander" tool: an older (2014) run over FreeBSD tree was useful as a
starting point.
2017-11-20 19:43:44 +00:00
Gleb Smirnoff
cc487c1697 Reduce in_pcbinfo_init() by two params. No users supply any flags to this
function (they used to say UMA_ZONE_NOFREE), so flag parameter goes away.
The zone_fini parameter also goes away.  Previously no protocols (except
divert) supplied zone_fini function, so inpcb locks were leaked with slabs.
This was okay while zones were allocated with UMA_ZONE_NOFREE flag, but now
this is a leak.  Fix that by suppling inpcb_fini() function as fini method
for all inpcb zones.
2017-05-15 21:58:36 +00:00
Gleb Smirnoff
cc65eb4e79 Hide struct inpcb, struct tcpcb from the userland.
This is a painful change, but it is needed.  On the one hand, we avoid
modifying them, and this slows down some ideas, on the other hand we still
eventually modify them and tools like netstat(1) never work on next version of
FreeBSD.  We maintain a ton of spares in them, and we already got some ifdef
hell at the end of tcpcb.

Details:
- Hide struct inpcb, struct tcpcb under _KERNEL || _WANT_FOO.
- Make struct xinpcb, struct xtcpcb pure API structures, not including
  kernel structures inpcb and tcpcb inside.  Export into these structures
  the fields from inpcb and tcpcb that are known to be used, and put there
  a ton of spare space.
- Make kernel and userland utilities compilable after these changes.
- Bump __FreeBSD_version.

Reviewed by:	rrs, gnn
Differential Revision:	D10018
2017-03-21 06:39:49 +00:00
Warner Losh
fbbd9655e5 Renumber copyright clause 4
Renumber cluase 4 to 3, per what everybody else did when BSD granted
them permission to remove clause 3. My insistance on keeping the same
numbering for legal reasons is too pedantic, so give up on that point.

Submitted by:	Jan Schaumann <jschauma@stevens.edu>
Pull Request:	https://github.com/freebsd/freebsd/pull/96
2017-02-28 23:42:47 +00:00
Andrey V. Elsukov
fcf596178b Merge projects/ipsec into head/.
Small summary
 -------------

o Almost all IPsec releated code was moved into sys/netipsec.
o New kernel modules added: ipsec.ko and tcpmd5.ko. New kernel
  option IPSEC_SUPPORT added. It enables support for loading
  and unloading of ipsec.ko and tcpmd5.ko kernel modules.
o IPSEC_NAT_T option was removed. Now NAT-T support is enabled by
  default. The UDP_ENCAP_ESPINUDP_NON_IKE encapsulation type
  support was removed. Added TCP/UDP checksum handling for
  inbound packets that were decapsulated by transport mode SAs.
  setkey(8) modified to show run-time NAT-T configuration of SA.
o New network pseudo interface if_ipsec(4) added. For now it is
  build as part of ipsec.ko module (or with IPSEC kernel).
  It implements IPsec virtual tunnels to create route-based VPNs.
o The network stack now invokes IPsec functions using special
  methods. The only one header file <netipsec/ipsec_support.h>
  should be included to declare all the needed things to work
  with IPsec.
o All IPsec protocols handlers (ESP/AH/IPCOMP protosw) were removed.
  Now these protocols are handled directly via IPsec methods.
o TCP_SIGNATURE support was reworked to be more close to RFC.
o PF_KEY SADB was reworked:
  - now all security associations stored in the single SPI namespace,
    and all SAs MUST have unique SPI.
  - several hash tables added to speed up lookups in SADB.
  - SADB now uses rmlock to protect access, and concurrent threads
    can do SA lookups in the same time.
  - many PF_KEY message handlers were reworked to reflect changes
    in SADB.
  - SADB_UPDATE message was extended to support new PF_KEY headers:
    SADB_X_EXT_NEW_ADDRESS_SRC and SADB_X_EXT_NEW_ADDRESS_DST. They
    can be used by IKE daemon to change SA addresses.
o ipsecrequest and secpolicy structures were cardinally changed to
  avoid locking protection for ipsecrequest. Now we support
  only limited number (4) of bundled SAs, but they are supported
  for both INET and INET6.
o INPCB security policy cache was introduced. Each PCB now caches
  used security policies to avoid SP lookup for each packet.
o For inbound security policies added the mode, when the kernel does
  check for full history of applied IPsec transforms.
o References counting rules for security policies and security
  associations were changed. The proper SA locking added into xform
  code.
o xform code was also changed. Now it is possible to unregister xforms.
  tdb_xxx structures were changed and renamed to reflect changes in
  SADB/SPDB, and changed rules for locking and refcounting.

Reviewed by:	gnn, wblock
Obtained from:	Yandex LLC
Relnotes:	yes
Sponsored by:	Yandex LLC
Differential Revision:	https://reviews.freebsd.org/D9352
2017-02-06 08:49:57 +00:00
Michael Tuexen
24209f0122 Ensure that the buffer length and the length provided in the IPv4
header match when using a raw socket to send IPv4 packets and
providing the header. If they don't match, let send return -1
and set errno to EINVAL.

Before this patch is was only enforced that the length in the header
is not larger then the buffer length.

PR:			212283
Reviewed by:		ae, gnn
MFC after:		1 week
Differential Revision:	https://reviews.freebsd.org/D9161
2017-01-13 10:55:26 +00:00
Kevin Lo
c3bef61e58 Remove the 4.3BSD compatible macro m_copy(), use m_copym() instead.
Reviewed by:	gnn
Differential Revision:	https://reviews.freebsd.org/D7878
2016-09-15 07:41:48 +00:00
Bjoern A. Zeeb
3f58662dd9 The pr_destroy field does not allow us to run the teardown code in a
specific order.  VNET_SYSUNINITs however are doing exactly that.
Thus remove the VIMAGE conditional field from the domain(9) protosw
structure and replace it with VNET_SYSUNINITs.
This also allows us to change some order and to make the teardown functions
file local static.
Also convert divert(4) as it uses the same mechanism ip(4) and ip6(4) use
internally.

Slightly reshuffle the SI_SUB_* fields in kernel.h and add a new ones, e.g.,
for pfil consumers (firewalls), partially for this commit and for others
to come.

Reviewed by:		gnn, tuexen (sctp), jhb (kernel.h)
Obtained from:		projects/vnet
MFC after:		2 weeks
X-MFC:			do not remove pr_destroy
Sponsored by:		The FreeBSD Foundation
Differential Revision:	https://reviews.freebsd.org/D6652
2016-06-01 10:14:04 +00:00
Michael Tuexen
6d7270a580 Send an ICMP packet indicating destination unreachable/protocol
unreachable if we don't handle the packet in the kernel and not
in userspace.

MFC after:	1 week
2016-05-25 15:54:21 +00:00
Michael Tuexen
ad2cbb09ef Count packets as not being delivered only if they are neither
processed by a kernel handler nor by a raw socket.

MFC after:	1 week
2016-05-25 13:48:26 +00:00
Pedro F. Giffuni
99d628d577 netinet: for pointers replace 0 with NULL.
These are mostly cosmetical, no functional change.

Found with devel/coccinelle.

Reviewed by:	ae. tuexen
2016-04-15 15:46:41 +00:00
Bjoern A. Zeeb
e18b26d377 Mfp: r296345
No need to keep type stability on raw sockets zone.
We've also been running with a KASSERT since r222488 to make sure the
ipi_count is 0 on destroy.

PR:		164763
Reviewed by:	gnn
MFC after:	2 weeks
Sponsored by:	The FreeBSD Foundation
Differential Revision:	https://reviews.freebsd.org/D5735
2016-04-09 10:44:57 +00:00
Alexander V. Chernikov
ea8d14925c Remove sys/eventhandler.h from net/route.h
Reviewed by:	ae
2016-01-09 09:34:39 +00:00
Andrey V. Elsukov
cc0a3c8ca4 Convert in_ifaddr_lock and in6_ifaddr_lock to rmlock.
Both are used to protect access to IP addresses lists and they can be
acquired for reading several times per packet. To reduce lock contention
it is better to use rmlock here.

Reviewed by:	gnn (previous version)
Obtained from:	Yandex LLC
Sponsored by:	Yandex LLC
Differential Revision:	https://reviews.freebsd.org/D3149
2015-07-29 08:12:05 +00:00
Gleb Smirnoff
6d947416cc o Use new function ip_fillid() in all places throughout the kernel,
where we want to create a new IP datagram.
o Add support for RFC6864, which allows to set IP ID for atomic IP
  datagrams to any value, to improve performance. The behaviour is
  controlled by net.inet.ip.rfc6864 sysctl knob, which is enabled by
  default.
o In case if we generate IP ID, use counter(9) to improve performance.
o Gather all code related to IP ID into ip_id.c.

Differential Revision:		https://reviews.freebsd.org/D2177
Reviewed by:			adrian, cy, rpaulo
Tested by:			Emeric POUPON <emeric.poupon stormshield.eu>
Sponsored by:			Netflix
Sponsored by:			Nginx, Inc.
Relnotes:			yes
2015-04-01 22:26:39 +00:00
Gleb Smirnoff
6df8a71067 Remove SYSCTL_VNET_* macros, and simply put CTLFLAG_VNET where needed.
Sponsored by:	Nginx, Inc.
2014-11-07 09:39:05 +00:00
Gleb Smirnoff
c26544aa7f Make SOCK_RAW sockets to be truly raw, not modifying received and sent
packets at all. Swapping byte order on SOCK_RAW was actually a bug, an
artifact from the BSD network stack, that used to convert a packet to
native byte order once it is received by kernel.

Other operating systems didn't follow this, and later other BSD
descendants fixed this, leaving us alone with the bug. Now it is
clear that we should fix the bug.

In collaboration with:	Olivier Cochard-Labbé <olivier cochard.me>
See also:		https://wiki.freebsd.org/SOCK_RAW
Sponsored by:		Nginx, Inc.
2014-09-01 14:04:51 +00:00
Kevin Lo
73d76e77b6 Change pr_output's prototype to avoid the need for explicit casts.
This is a follow up to r269699.

Phabric:	D564
Reviewed by:	jhb
2014-08-15 02:43:02 +00:00
Kevin Lo
8f5a8818f5 Merge 'struct ip6protosw' and 'struct protosw' into one. Now we have
only one protocol switch structure that is shared between ipv4 and ipv6.

Phabric:	D476
Reviewed by:	jhb
2014-08-08 01:57:15 +00:00
Steven Hartland
ae19083248 Fix jailed raw sockets not setting the correct source address by
calling in_pcbladdr instead of prison_get_ip4

MFC after:	1 month
2014-04-24 12:52:31 +00:00
Gleb Smirnoff
fe9bfbcf5a netinet code no longer uses IFA_RTSELF. 2013-11-05 07:45:20 +00:00
Gleb Smirnoff
237bf7f773 Cleanup in_ifscrub(), which is just an entry to in_scrubprefix(). 2013-11-01 10:18:41 +00:00
Gleb Smirnoff
76039bc84f The r48589 promised to remove implicit inclusion of if_var.h soon. Prepare
to this event, adding if_var.h to files that do need it. Also, include
all includes that now are included due to implicit pollution via if_var.h

Sponsored by:	Netflix
Sponsored by:	Nginx, Inc.
2013-10-26 17:58:36 +00:00
Gleb Smirnoff
eb1b1807af Mechanically substitute flags from historic mbuf allocator with
malloc(9) flags within sys.

Exceptions:

- sys/contrib not touched
- sys/mbuf.h edited manually
2012-12-05 08:04:20 +00:00
Gleb Smirnoff
8ad458a471 Do not reduce ip_len by size of IP header in the ip_input()
before passing a packet to protocol input routines.
  For several protocols this mean that now protocol needs to
do subtraction itself, and for another half this means that
we do not need to add header length back to the packet.

  Make ip_stripoptions() to adjust ip_len, since now we enter
this function with a packet header whose ip_len does represent
length of entire packet, not payload only.
2012-10-23 08:33:13 +00:00
Gleb Smirnoff
8f134647ca Switch the entire IPv4 stack to keep the IP packet header
in network byte order. Any host byte order processing is
done in local variables and host byte order values are
never[1] written to a packet.

  After this change a packet processed by the stack isn't
modified at all[2] except for TTL.

  After this change a network stack hacker doesn't need to
scratch his head trying to figure out what is the byte order
at the given place in the stack.

[1] One exception still remains. The raw sockets convert host
byte order before pass a packet to an application. Probably
this would remain for ages for compatibility.

[2] The ip_input() still subtructs header len from ip->ip_len,
but this is planned to be fixed soon.

Reviewed by:	luigi, Maxim Dounin <mdounin mdounin.ru>
Tested by:	ray, Olivier Cochard-Labbe <olivier cochard.me>
2012-10-22 21:09:03 +00:00
Gleb Smirnoff
d6d3f01e0a Merge the projects/pf/head branch, that was worked on for last six months,
into head. The most significant achievements in the new code:

 o Fine grained locking, thus much better performance.
 o Fixes to many problems in pf, that were specific to FreeBSD port.

New code doesn't have that many ifdefs and much less OpenBSDisms, thus
is more attractive to our developers.

  Those interested in details, can browse through SVN log of the
projects/pf/head branch. And for reference, here is exact list of
revisions merged:

r232043, r232044, r232062, r232148, r232149, r232150, r232298, r232330,
r232332, r232340, r232386, r232390, r232391, r232605, r232655, r232656,
r232661, r232662, r232663, r232664, r232673, r232691, r233309, r233782,
r233829, r233830, r233834, r233835, r233836, r233865, r233866, r233868,
r233873, r234056, r234096, r234100, r234108, r234175, r234187, r234223,
r234271, r234272, r234282, r234307, r234309, r234382, r234384, r234456,
r234486, r234606, r234640, r234641, r234642, r234644, r234651, r235505,
r235506, r235535, r235605, r235606, r235826, r235991, r235993, r236168,
r236173, r236179, r236180, r236181, r236186, r236223, r236227, r236230,
r236252, r236254, r236298, r236299, r236300, r236301, r236397, r236398,
r236399, r236499, r236512, r236513, r236525, r236526, r236545, r236548,
r236553, r236554, r236556, r236557, r236561, r236570, r236630, r236672,
r236673, r236679, r236706, r236710, r236718, r237154, r237155, r237169,
r237314, r237363, r237364, r237368, r237369, r237376, r237440, r237442,
r237751, r237783, r237784, r237785, r237788, r237791, r238421, r238522,
r238523, r238524, r238525, r239173, r239186, r239644, r239652, r239661,
r239773, r240125, r240130, r240131, r240136, r240186, r240196, r240212.

I'd like to thank people who participated in early testing:

Tested by:	Florian Smeets <flo freebsd.org>
Tested by:	Chekaluk Vitaly <artemrts ukr.net>
Tested by:	Ben Wilber <ben desync.com>
Tested by:	Ian FREISLICH <ianf cloudseed.co.za>
2012-09-08 06:41:54 +00:00
Bjoern A. Zeeb
762ad1d614 As I came by and noticed add a comment that inp locking is a bit optistic
(read: non-existent) here and should be fixed.
2012-01-02 09:18:58 +00:00
Andre Oppermann
50b1479e65 Add back the IP header length to the total packet length field on
raw IP sockets.  It was deducted in ip_input() in preparation for
protocols interested only in the payload.

On raw sockets the IP header should be delivered as it at came in
from the network except for the byte order swaps in some fields.

This brings us in line with all other OS'es that provide raw
IP sockets.

Reported by: Matthew Cini Sarreo <mcins1-at-gmail.com>
MFC after: 3 days
2011-10-07 13:43:01 +00:00
Bjoern A. Zeeb
e0bfbfce79 Update packet filter (pf) code to OpenBSD 4.5.
You need to update userland (world and ports) tools
to be in sync with the kernel.

Submitted by:	mlaier
Submitted by:	eri
2011-06-28 11:57:25 +00:00
Robert Watson
52cd27cb58 Implement a CPU-affine TCP and UDP connection lookup data structure,
struct inpcbgroup.  pcbgroups, or "connection groups", supplement the
existing inpcbinfo connection hash table, which when pcbgroups are
enabled, might now be thought of more usefully as a per-protocol
4-tuple reservation table.

Connections are assigned to connection groups base on a hash of their
4-tuple; wildcard sockets require special handling, and are members
of all connection groups.  During a connection lookup, a
per-connection group lock is employed rather than the global pcbinfo
lock.  By aligning connection groups with input path processing,
connection groups take on an effective CPU affinity, especially when
aligned with RSS work placement (see a forthcoming commit for
details).  This eliminates cache line migration associated with
global, protocol-layer data structures in steady state TCP and UDP
processing (with the exception of protocol-layer statistics; further
commit to follow).

Elements of this approach were inspired by Willman, Rixner, and Cox's
2006 USENIX paper, "An Evaluation of Network Stack Parallelization
Strategies in Modern Operating Systems".  However, there are also
significant differences: we maintain the inpcb lock, rather than using
the connection group lock for per-connection state.

Likewise, the focus of this implementation is alignment with NIC
packet distribution strategies such as RSS, rather than pure software
strategies.  Despite that focus, software distribution is supported
through the parallel netisr implementation, and works well in
configurations where the number of hardware threads is greater than
the number of NIC input queues, such as in the RMI XLR threaded MIPS
architecture.

Another important difference is the continued maintenance of existing
hash tables as "reservation tables" -- these are useful both to
distinguish the resource allocation aspect of protocol name management
and the more common-case lookup aspect.  In configurations where
connection tables are aligned with hardware hashes, it is desirable to
use the traditional lookup tables for loopback or encapsulated traffic
rather than take the expense of hardware hashes that are hard to
implement efficiently in software (such as RSS Toeplitz).

Connection group support is enabled by compiling "options PCBGROUP"
into your kernel configuration; for the time being, this is an
experimental feature, and hence is not enabled by default.

Subject to the limited MFCability of change dependencies in inpcb,
and its change to the inpcbinfo init function signature, this change
in principle could be merged to FreeBSD 8.x.

Reviewed by:    bz
Sponsored by:   Juniper Networks, Inc.
2011-06-06 12:55:02 +00:00