Commit Graph

2782 Commits

Author SHA1 Message Date
Lawrence Stewart
253a3814d4 Revert r228986 until it can be reworked to avoid panicing the kernel when the
same interface is attached multiple times with different DLTs, as is done in
net80211 for example.

Reported by:	adrian
2011-12-31 07:21:28 +00:00
Lawrence Stewart
0f89fc22f3 - Introduce the net.bpf.tscfg sysctl tree and associated code so as to make one
aspect of time stamp configuration per interface rather than per BPF
  descriptor. Prior to this, the order in which BPF devices were opened and the
  per descriptor time stamp configuration settings could cause non-deterministic
  and unintended behaviour with respect to time stamping. With the new scheme, a
  BPF attached interface's tscfg sysctl entry can be set to "default", "none",
  "fast", "normal" or "external". Setting "default" means use the system default
  option (set with the net.bpf.tscfg.default sysctl), "none" means do not
  generate time stamps for tapped packets, "fast" means generate time stamps for
  tapped packets using a hz granularity system clock read, "normal" means
  generate time stamps for tapped packets using a full timecounter granularity
  system clock read and "external" (currently unimplemented) means use the time
  stamp provided with the packet from an underlying source.

- Utilise the recently introduced sysclock_getsnapshot() and
  sysclock_snap2bintime() KPIs to ensure the system clock is only read once per
  packet, regardless of the number of BPF descriptors and time stamp formats
  requested. Use the per BPF attached interface time stamp configuration to
  control if sysclock_getsnapshot() is called and whether the system clock read
  is fast or normal. The per BPF descriptor time stamp configuration is then
  used to control how the system clock snapshot is converted to a bintime by
  sysclock_snap2bintime().

- Remove all FAST related BPF descriptor flag variants. Performing a "fast"
  read of the system clock is now controlled per BPF attached interface using
  the net.bpf.tscfg sysctl tree.

- Update the bpf.4 man page.

Committed on behalf of Julien Ridoux and Darryl Veitch from the University of
Melbourne, Australia, as part of the FreeBSD Foundation funded "Feed-Forward
Clock Synchronization Algorithms" project.

For more information, see http://www.synclab.org/radclock/

In collaboration with:	Julien Ridoux (jridoux at unimelb edu au)
2011-12-30 08:57:58 +00:00
Pyun YongHyeon
1ad7a2570d Update if_obytes and if_omcast after successful transmit.
While I'm here update if_oerrors if parent interface of vlan is not
up and running.  Previously it updated collision counter and it was
confusing to interprete it.

PR:		kern/163478
Reviewed by:	glebius, jhb
Tested by:	Joe Holden < lists <> rewt dot org dot uk >
2011-12-29 18:40:58 +00:00
Gleb Smirnoff
7121247312 Provide ABI compatibility shim to enable configuring of addresses
with ifconfig(8) prior to r228571.

Requested by:	brooks
2011-12-21 12:39:08 +00:00
Gleb Smirnoff
f08535f872 Restore a feature that was present in 5.x and 6.x, and was cleared in
7.x, 8.x and 9.x with pf(4) imports: pfsync(4) should suppress CARP
preemption, while it is running its bulk update.

However, reimplement the feature in more elegant manner, that is
partially inspired by newer OpenBSD:

- Rename term "suppression" to "demotion", to match with OpenBSD.
- Keep a global demotion factor, that can be raised by several
  conditions, for now these are:
  - interface goes down
  - carp(4) has problems with ip_output() or ip6_output()
  - pfsync performs bulk update
- Unlike in OpenBSD the demotion factor isn't a counter, but
  is actual value added to advskew. The adjustment values for
  particular error conditions are also configurable, and their
  defaults are maximum advskew value, so a single failure bumps
  demotion to maximum. This is for POLA compatibility, and should
  satisfy most users.
- Demotion factor is a writable sysctl, so user can do
  foot shooting, if he desires to.
2011-12-20 13:53:31 +00:00
Gleb Smirnoff
08b68b0e4c A major overhaul of the CARP implementation. The ip_carp.c was started
from scratch, copying needed functionality from the old implemenation
on demand, with a thorough review of all code. The main change is that
interface layer has been removed from the CARP. Now redundant addresses
are configured exactly on the interfaces, they run on.

The CARP configuration itself is, as before, configured and read via
SIOCSVH/SIOCGVH ioctls. A new prefix created with SIOCAIFADDR or
SIOCAIFADDR_IN6 may now be configured to a particular virtual host id,
which makes the prefix redundant.

ifconfig(8) semantics has been changed too: now one doesn't need
to clone carpXX interface, he/she should directly configure a vhid
on a Ethernet interface.

To supply vhid data from the kernel to an application the getifaddrs(8)
function had been changed to pass ifam_data with each address. [1]

The new implementation definitely closes all PRs related to carp(4)
being an interface, and may close several others. It also allows
to run a single redundant IP per interface.

Big thanks to Bjoern Zeeb for his help with inet6 part of patch, for
idea on using ifam_data and for several rounds of reviewing!

PR:		kern/117000, kern/126945, kern/126714, kern/120130, kern/117448
Reviewed by:	bz
Submitted by:	bz [1]
2011-12-16 12:16:56 +00:00
Gleb Smirnoff
f3909e37ff Simplify rtrequest(RTM_ADD): ifa can't be NULL after rt_getifa_fib(). 2011-12-15 12:49:10 +00:00
Brooks Davis
f26fa169e7 Remove the unused if_free_type() function.
X-MFC after:	never
2011-12-09 23:26:28 +00:00
Luigi Rizzo
506cc70cce 1. Fix the handling of link reset while in netmap more.
A link reset now is completely transparent for the netmap client:
   even if the NIC resets its own ring (e.g. restarting from 0),
   the client will not see any change in the current rx/tx positions,
   because the driver will keep track of the offset between the two.

2. make the device-specific code more uniform across different drivers
   There were some inconsistencies in the implementation of the netmap
   support routines, now drivers have been aligned to a common
   code structure.

3. import netmap support for ixgbe . This is implemented as a very
   small patch for ixgbe.c (233 lines, 11 chunks, mostly comments:
   in total the patch has only 54 lines of new code) , as most of
   the code is in an external file sys/dev/netmap/ixgbe_netmap.h ,
   following some initial comments from Jack Vogel about making
   changes less intrusive.
   (Note, i have emailed Jack multiple times asking if he had
   comments on this structure of the code; i got no reply so
   i assume he is fine with it).

Support for other drivers (em, lem, re, igb) will come later.

"ixgbe" is now the reference driver for netmap support. Both the
external file (sys/dev/netmap/ixgbe_netmap.h) and the device-specific
patches (in sys/dev/ixgbe/ixgbe.c) are heavily commented and should
serve as a reference for other device drivers.

Tested on i386 and amd64 with the pkt-gen program in tools/tools/netmap,
the sender does 14.88 Mpps at 1050 Mhz and 14.2 Mpps at 900 MHz
on an i7-860 with 4 cores and 82599 card. Haven't tried yet more
aggressive optimizations such as adding 'prefetch' instructions
in the time-critical parts of the code.
2011-12-05 12:06:53 +00:00
Lawrence Stewart
3e47c78798 Revert r227778 in preparation for committing reworked patches in its place. 2011-11-29 12:55:26 +00:00
John Baldwin
d9b1d61535 Change the if_vlan driver to use if_transmit for forwarding packets to the
parent interface.  This avoids the overhead of queueing a packet to an IFQ
only to immediately dequeue it again.

Suggested by:	np
Reviewed by:	brooks
MFC after:	1 month
2011-11-28 19:35:08 +00:00
Gleb Smirnoff
2e9fff5b18 - Use generic alloc_unr(9) allocator for if_clone, instead
of hand-made.
- When registering new cloner, check whether a cloner with
  same name already exist.
- When allocating unit, also check with help of ifunit()
  whether such interface already exist or not. [1]

PR:		kern/162789 [1]
2011-11-28 14:44:59 +00:00
Gleb Smirnoff
c0ba290b5f Improve logging:
- don't hardcode function name
- use LOG_DEBUG for such a debug message
- print error value
2011-11-22 19:42:17 +00:00
Lawrence Stewart
b6f1c7db32 - When feed-forward clock support is compiled in, change the BPF header to
contain both a regular timestamp obtained from the system clock and the
  current feed-forward ffcounter value. This enables new possibilities including
  comparison of timekeeping performance and timestamp correction during post
  processing.

- Add the net.bpf.ffclock_tstamp sysctl to provide a choice between timestamping
  packets using the feedback or feed-forward system clock.

Committed on behalf of Julien Ridoux and Darryl Veitch from the University of
Melbourne, Australia, as part of the FreeBSD Foundation funded "Feed-Forward
Clock Synchronization Algorithms" project.

For more information, see http://www.synclab.org/radclock/

Submitted by:	Julien Ridoux (jridoux at unimelb edu au)
2011-11-21 04:17:24 +00:00
Luigi Rizzo
68b8534bdf Bring in support for netmap, a framework for very efficient packet
I/O from userspace, capable of line rate at 10G, see

	http://info.iet.unipi.it/~luigi/netmap/

At this time I am bringing in only the generic code (sys/dev/netmap/
plus two headers under sys/net/), and some sample applications in
tools/tools/netmap. There is also a manpage in share/man/man4 [1]

In order to make use of the framework you need to build a kernel
with "device netmap", and patch individual drivers with the code
that you can find in

	sys/dev/netmap/head.diff

The file will go away as the relevant pieces are committed to
the various device drivers, which should happen in a few days
after talking to the driver maintainers.

Netmap support is available at the moment for Intel 10G and 1G
cards (ixgbe, em/lem/igb), and for the Realtek 1G card ("re").
I have partial patches for "bge" and am starting to work on "cxgbe".
Hopefully changes are trivial enough so interested third parties
can submit their patches. Interested people can contact me
for advice on how to add netmap support to specific devices.

CREDITS:
    Netmap has been developed by Luigi Rizzo and other collaborators
    at the Universita` di Pisa, and supported by EU project CHANGE
    (http://www.change-project.eu/)
    The code is distributed under a BSD Copyright.

[1] In my opinion is a bad idea to have all manpage in one directory.
  We should place kernel documentation in the same dir that contains
  the code, which would make it much simpler to keep doc and code
  in sync, reduce the clutter in share/man/ and incidentally is
  the policy used for all of userspace code.
  Makefiles and doc tools can be trivially adjusted to find the
  manpages in the relevant subdirs.
2011-11-17 12:17:39 +00:00
Robert Millan
ea4d9a14f1 Remove a few bits of FreeBSD 2.x compatibility code.
Approved by:	kib (mentor)
2011-11-14 18:21:27 +00:00
Brooks Davis
4b22573a89 In r191367 the need for if_free_type() was removed and a new member
if_alloctype was used to store the origional interface type.  Take
advantage of this change by removing all existing uses of if_free_type()
in favor of if_free().

MFC after:	1 Month
2011-11-11 22:57:52 +00:00
Ed Schouten
6472ac3d8a Mark all SYSCTL_NODEs static that have no corresponding SYSCTL_DECLs.
The SYSCTL_NODE macro defines a list that stores all child-elements of
that node. If there's no SYSCTL_DECL macro anywhere else, there's no
reason why it shouldn't be static.
2011-11-07 15:43:11 +00:00
Ed Schouten
d745c852be Mark MALLOC_DEFINEs static that have no corresponding MALLOC_DECLAREs.
This means that their use is restricted to a single C file.
2011-11-07 06:44:47 +00:00
Max Laier
3ca1a2d6a0 Fix a use-after-free/redzone issue in the routing code.
Reported by (repeatedly):	Mike Tancsa
Prodded by (repeatedly):	bz
Forgotten by (repeatedly):	mlaier
MFC after:			2 weeks
2011-11-03 18:33:30 +00:00
Gleb Smirnoff
a0af7c3edb Add macro IF_DEQUEUE_ALL(ifq, m), that takes the entire mbuf chain off
the queue. It can be utilized in queue processing to avoid multiple
locking/unlocking.
2011-10-27 09:45:12 +00:00
Qing Li
46a70de2b0 The host-id/interface-id can have a specific value and is properly
masked out when adding a prefix route through the "route" command.
However, when deleting the route, simply changing the command keyword
from "add" to "delete" does not work. The failoure is observed in
both IPv4 and IPv6 route insertion. The patch makes the route command
behavior consistent between the "add" and the "delete" operation.

MFC after:	1 week
2011-10-25 00:34:39 +00:00
Ed Schouten
cf05e311ea Add missing #includes.
According to POSIX, these two header files should be able to be included
by themselves, not depending on other headers. The <net/if.h> header
uses struct sockaddr when __BSD_VISIBLE=1, while <netinet/tcp.h> uses
integer datatypes (u_int32_t, u_short, etc).

MFC after:	2 months
2011-10-21 12:58:34 +00:00
Ed Schouten
a185bd12f3 Get rid of D_PSEUDO.
It seems the D_PSEUDO flag was meant to allow make_dev() to return NULL.
Nowadays we have a different interface for that; make_dev_p(). There's
no need to keep it there.

While there, remove an unneeded D_NEEDMINOR from the gpio driver.

Discussed with:	gonzo@ (gpio)
2011-10-18 08:09:44 +00:00
Bjoern A. Zeeb
528737fdfe Pass the fibnum where we need filtering of the message on the
rtsock allowing routing daemons to filter routing updates on an
rtsock per FIB.

Adjust raw_input() and split it into wrapper and a new function
taking an optional callback argument even though we only have one
consumer [1] to keep the hackish flags local to rtsock.c.

PR:		kern/134931
Submitted by:	multiple (see PR)
Suggested by:	rwatson [1]
Reviewed by:	rwatson
MFC after:	3 days
2011-09-28 13:48:36 +00:00
Kip Macy
1eeb6d97d0 Make KBI changes required for future MFCing of inpcb rtentry / llentry caching.
Reviewed by:	rwatson, bz
Approved by:	re (kib)
2011-09-20 20:27:26 +00:00
Kip Macy
8451d0dd78 In order to maximize the re-usability of kernel code in user space this
patch modifies makesyscalls.sh to prefix all of the non-compatibility
calls (e.g. not linux_, freebsd32_) with sys_ and updates the kernel
entry points and all places in the code that use them. It also
fixes an additional name space collision between the kernel function
psignal and the libc function of the same name by renaming the kernel
psignal kern_psignal(). By introducing this change now we will ease future
MFCs that change syscalls.

Reviewed by:	rwatson
Approved by:	re (bz)
2011-09-16 13:58:51 +00:00
Andrew Thompson
0fe082e7d5 On the first loop for generating a bridge MAC address use the local
hostid, this gives a good chance of keeping the same address over
reboots. This is intended to help IPV6 and similar which generate
their addresses from the mac.

PR:		kern/160300
Submitted by:	mdodd
Approved by:	re (kib)
2011-09-04 22:06:32 +00:00
Bjoern A. Zeeb
3d07127c64 When adding IPv6 fwd support to ipfw in r225044 these two files were
not committed.  Initialize next_hop6 to align with the IPv4 code.

PR:		bin/117214
MFC after:	3 weeks
X-MFC with:	r225044
Approved by:	re (kib)
2011-08-27 08:49:55 +00:00
Attilio Rao
6aba400a70 Fix a deficiency in the selinfo interface:
If a selinfo object is recorded (via selrecord()) and then it is
quickly destroyed, with the waiters missing the opportunity to awake,
at the next iteration they will find the selinfo object destroyed,
causing a PF#.

That happens because the selinfo interface has no way to drain the
waiters before to destroy the registered selinfo object. Also this
race is quite rare to get in practice, because it would require a
selrecord(), a poll request by another thread and a quick destruction
of the selrecord()'ed selinfo object.

Fix this by adding the seldrain() routine which should be called
before to destroy the selinfo objects (in order to avoid such case),
and fix the present cases where it might have already been called.
Sometimes, the context is safe enough to prevent this type of race,
like it happens in device drivers which installs selinfo objects on
poll callbacks. There, the destruction of the selinfo object happens
at driver detach time, when all the filedescriptors should be already
closed, thus there cannot be a race.
For this case, mfi(4) device driver can be set as an example, as it
implements a full correct logic for preventing this from happening.

Sponsored by:	Sandvine Incorporated
Reported by:	rstone
Tested by:	pluknet
Reviewed by:	jhb, kib
Approved by:	re (bz)
MFC after:	3 weeks
2011-08-25 15:51:54 +00:00
Qing Li
fc96aabef1 When the RADIX_MPATH kernel option is enabled, the RADIX_MPATH code tries
to find the first route node of an ECMP chain before executing the route
command. If the system has a default route, and the specific route argument
to the command does not exist in the routing table, then the default route
would be reached. The current code does not verify the reached node matches
the given route argument, therefore erroneous removed the entry. This patch
fixes that bug.

Approved by:	re
MFC after:	3 days
2011-08-25 04:31:20 +00:00
Kevin Lo
e9ff3d45e4 In rtinit1(), before rtrequest1_fib() is called, info.rti_flags is
initialized by flags (function argument) or-ed with ifa->ifa_flags.
If both NIC has a loopback route to itself, so IFA_RTSELF is set on ifa(s).
As IFA_RTSELF is defined by RTF_HOST, rtrequest1_fib() is called with
RTF_HOST flag even if netmask is not NULL. Consequently, netmask is set
to zero in rtrequest1_fib(), and request to add network route is changed
under hands to request to add host route.

Tested by:	Andrew Boyer <aboyer at averesystems.com>
Submitted by:	Svatopluk Kraus <onwahe at gmail dot com>
Approved by:	re (hrs)
2011-08-08 05:25:51 +00:00
Sergey Kandaurov
c94a66f8ae Add missing MODULE_VERSION() definition to protect against duplicating
module loads.

PR:		kern/159345
Reported by:	Eugene Grosbein <egrosbein att rdtc ru>
Tested by:	Eugene Grosbein <egrosbein att rdtc ru>
Approved by:	re (kib)
MFC after:	1 week
2011-08-01 11:24:55 +00:00
Bjoern A. Zeeb
d9a362862c Add spares to the network stack for FreeBSD-9:
- TCP keep* timers
- TCP UTO (adjust from what was there already)
- netmap
- route caching
- user cookie (temporary to allow for the real fix)

Slightly re-shuffle struct ifnet moving fields out of the middle
of spares and to better align.

Discussed with:	rwatson (slightly earlier version)
2011-07-17 21:15:20 +00:00
Mark Peek
a4980a95b5 Clear the filter memory area before using it. Leaving it uninitialized may
leak previous kernel stack contents through a malicioius BPF filter.

PR:		kern/158880
Submitted by:	Guy Harris
Obtained from:	OpenBSD
MFC after:	1 week
2011-07-14 21:06:22 +00:00
Marko Zec
13e255fab7 Permit ARP to proceed for IPv4 host routes for which the gateway is the
same as the host address.  This already works fine for INET6 and ND6.

While here, remove two function pointers from struct lltable which are
only initialized but never used.

MFC after:	3 days
2011-07-08 09:38:33 +00:00
Andrew Thompson
6069a2c0bd Grab the rlock before checking if our interface is enabled, it could be
possible to hit a dead pointer when changing interfaces.

PR:		kern/156978
Submitted by:	Andrew Boyer
MFC after:	1 week
2011-07-07 20:02:09 +00:00
Bjoern A. Zeeb
a34c6aeb85 Tag mbufs of all incoming frames or packets with the interface's FIB
setting (either default or if supported as set by SIOCSIFFIB, e.g.
from ifconfig).

Submitted by:	Alexander V. Chernikov (melifaro ipfw.ru)
Reviewed by:	julian
MFC after:	2 weeks
2011-07-03 16:08:38 +00:00
Bjoern A. Zeeb
43deddcdfe Remove extra white space to comply with style for the rest of the struct.
MFC after:	2 weeks
2011-07-03 15:34:09 +00:00
Bjoern A. Zeeb
35fd7bc020 Add infrastructure to allow all frames/packets received on an interface
to be assigned to a non-default FIB instance.

You may need to recompile world or ports due to the change of struct ifnet.

Submitted by:	cjsp
Submitted by:	Alexander V. Chernikov (melifaro ipfw.ru)
		(original versions)
Reviewed by:	julian
Reviewed by:	Alexander V. Chernikov (melifaro ipfw.ru)
MFC after:	2 weeks
X-MFC:		use spare in struct ifnet
2011-07-03 12:22:02 +00:00
Sergey Kandaurov
235195988b Update ifc_len field of struct ifconf passed for the ioctl SIOCGIFCONF32
(i.e. under COMPAT_FREEBSD32) in case ifconf() returned success to match
the native SIOCGIFCONF behavior.

PR:		kern/158369
Reported by:	Paul Procacci <pprocacci att gmail com>
MFC after:	1 week
2011-06-28 08:41:44 +00:00
Bjoern A. Zeeb
f5857e2d3d Garbage collect never used global, sysctl, externs.
MFC after:	1 week
2011-06-21 07:19:03 +00:00
Bjoern A. Zeeb
b8b8e0c981 Leave an extra comment about flowtable and IPv6 support rectifying a
previous comment.

MFC after:	1 week
2011-06-20 12:35:12 +00:00
Bjoern A. Zeeb
52dcd04ba3 gre(4) was using a field in the softc to detect possible recursion.
On MP systems this is not a usable solution anymore and could easily
lead to false positives triggering enough logging that even  using
the console was no longer usable (multiple parallel ping -f can do).

Switch to the suggested solution of using mbuf tags to carry per
packet state between gre_output() invocations.  Contrary to the
proposed solution modelled after gif(4) only allocate one mbuf tag
per packet rather than per packet and per gre_output() pass through.

As the sysctl to control the possible valid (gre in gre) nestings does
no sanity checks, make sure to always allocate space in the mbuf tag
for at least one, and at most 255 possible gre interfaces to detect
loops in addition to the counter.

Submitted by:	Cristian KLEIN (cristi net.utcluj.ro) (original version)
PR:		kern/114714
Reviewed by:	Cristian KLEIN (cristi net.utcluj.ro)
Reviewed bu:	Wooseog Choi (ben_choi hotmail.com)
Sponsored by:	Sandvine Incorporated
MFC after:	1 week
2011-06-18 09:34:03 +00:00
Luigi Rizzo
c9d658e9f7 Grab one of the ifcap bits for netmap, and enable printing in ifconfig.
Document the fact that we might want an IFCAP_CANTCHANGE mask,
even though the value is not yet used in sys/net/if.c

(asked on -current a week ago, no feedback so i assume no objection).
2011-06-14 12:40:55 +00:00
Marko Zec
2fe7ca2ca6 Set curvnet context in a callout-trigerred code path.
MFC after:	3 days
2011-06-07 20:46:03 +00:00
John Baldwin
190367ef1c Properly return an ENOBUFS error if a write to a tun(4) device fails
due to m_uiotombuf() failing.

While here, trim unneeded error handling related to tuninit() since it
can never fail.

Submitted by:	Martin Birgmeier  la5lbtyi aon at
Reviewed by:	glebius
MFC after:	1 week
2011-06-03 13:47:05 +00:00
Robert Watson
6cb52192fe Add an optional netisr dispatch point at ether_input(), but set the
default dispatch method to NETISR_DISPATCH_DIRECT in order to force
direct dispatch.  This adds a fairly negligble overhead without
changing default behavior, but in the future will allow deferred or
hybrid dispatch to other worker threads before link layer processing
has taken place.

For example, this could allow redistribution using RSS hashes
without ethernet header cache line hits, if the NIC was unable to
adequately implement load balancing to too small a number of input
queues -- perhaps due to hard queueset counts of 1, 3, or 8, but in
a modern system with 16-128 threads.  This can happen on highly
threaded systems, where you want want an ithread per core,
redistributing work to other queues, but also on virtualised systems
where hardware hashing is (or is not) available, but only a single
queue has been directed to one VCPU on a VM.

Note: this adds a previously non-present assertion about the
equivalence of the ifnet from which the packet is received, and the
ifnet stamped in the mbuf header.  I believe this assertion to
generally be true, but we'll find out soon -- if it's not, we might
have to add additional overhead in some cases to add an m_tag with
the originating ifnet pointer stored in it.

Reviewed by:    bz
MFC after:      3 weeks
Sponsored by:   Juniper Networks, Inc.
2011-06-01 20:00:25 +00:00
Nathan Whitehorn
d098f93019 On multi-core, multi-threaded PPC systems, it is important that the threads
be brought up in the order they are enumerated in the device tree (in
particular, that thread 0 on each core be brought up first). The SLIST
through which we loop to start the CPUs has all of its entries added with
SLIST_INSERT_HEAD(), which means it is in reverse order of enumeration
and so AP startup would always fail in such situations (causing a machine
check or RTAS failure). Fix this by changing the SLIST into an STAILQ,
and inserting new CPUs at the end.

Reviewed by:	jhb
2011-05-31 15:11:43 +00:00
Robert Watson
f2d2d69438 Rework netisr policy mechanism so that per-protocol dispatch policies can
be represented:

- A single policy namespace is defined, consisting of four possible
  policies: "default" to use the global default, "deferred" to force
  deferred dispatch, "direct" to employ direct dispatch where possible, and
  "hybrid" which makes a dynamic decision based on CPU affinity, ordering,
  etc.  Routines are implemented to convert between strings and an integer
  namespace.

- A new global variable, netisr_dispatch_policy, subsumes existing global
  variables for direct dispatch, forced direct dispatch, etc, and is used
  for explicit policy interpretation and composition.  Old variables remain
  so that they can be exported by legacy sysctls for use by old netstat(1)
  binaries.  A new sysctl and tunable, netisr.dispatch.policy, accepts the
  above strings for specifying a global policy default.

- The protocol registration structure, netisr_handler, grows an nh_dispatch
  field, which accepts a per-policy policy override.  The default value is
  '0', which corresponds to "default", meaning that protocols will accept
  the global default policy unless otherwise specified.

- Policies are now interpreted and composed explicitly at various points in
  packet dispatch; protocol policies override global policies.

- Protocols grow the ability to express a non-opinion about affinity even
  when implenting m2cpuid by returning NETISR_CPUID_NONE.  In that case, the
  framework falls back on source ordering, rather than simply using the
  current CPU.

These changes are in support of allowing link layer re-dispatch based on
RSS or similar hashes provided by NICs, especially in the case where the
number of hardware receive queues matches hardware core count, rather than
hardware thread count, requiring further software redistributeon.  (i.e.,
on RMI XLR).

MFC after:      3 weeks
Reviewed by:    bz
Sponsored by:   Juniper Networks, Inc.
2011-05-24 12:34:19 +00:00