Commit Graph

2445 Commits

Author SHA1 Message Date
Bjoern A. Zeeb
974524bf59 ip_gif_ttl/GIF_TTL are only used by the inet part in in_gif.c,
so put the initialization under #ifdef INET.
2009-06-10 13:39:51 +00:00
Bjoern A. Zeeb
74900cdf7f The llentry *lle is only used in cases of INET or INET6.
Put the variable declaration under proper #ifdefs.

In case variables are only needed for one of the two AFs
more them into proper scope.
2009-06-10 09:07:05 +00:00
Kip Macy
3576e2f4a2 revert to opt-in flowtable 2009-06-09 21:55:28 +00:00
Oleg Bulyzhin
dda10d624c Close long existed race with net.inet.ip.fw.one_pass = 0:
If packet leaves ipfw to other kernel subsystem (dummynet, netgraph, etc)
it carries pointer to matching ipfw rule. If this packet then reinjected back
to ipfw, ruleset processing starts from that rule. If rule was deleted
meanwhile, due to existed race condition panic was possible (as well as
other odd effects like parsing rules in 'reap list').

P.S. this commit changes ABI so userland ipfw related binaries should be
recompiled.

MFC after:	1 month
Tested by:	Mikolaj Golub
2009-06-09 21:27:11 +00:00
Kip Macy
15d13a59a3 make flowtable opt-out 2009-06-09 20:27:30 +00:00
Kip Macy
ee117d034c move jenkins hash to its own header in libkern 2009-06-09 20:21:40 +00:00
Kip Macy
a913be0917 - add drbr routines for accessing #qentries and conditionally dequeueing
- track bytes enqueued in buf_ring
2009-06-09 19:19:16 +00:00
Bjoern A. Zeeb
c2f16e371e Remove one INET dependency by calling the general
AF agnostic version for doing the routing lookup.

Reviewed by:	kmacy
2009-06-09 09:50:43 +00:00
Hiroki Sato
4cd5f57d6b Style fix.
Submitted by:	bz
2009-06-09 08:09:30 +00:00
Hiroki Sato
fb70e72b0c - Fix sanity check of GIFSOPTS ioctl.
- Rename option mask s/GIF_FULLOPTS/GIF_OPTMASK/

Spotted by:	Eygene Ryabinkin, delphij
2009-06-09 02:27:59 +00:00
Bjoern A. Zeeb
5c40c5e989 Remove two unneeded, hidden includes. 2009-06-08 20:04:46 +00:00
Bjoern A. Zeeb
8d8bc0182e After r193232 rt_tables in vnet.h are no longer indirectly dependent on
the ROUTETABLES kernel option thus there is no need to include opt_route.h
anymore in all consumers of vnet.h and no longer depend on it for module
builds.

Remove the hidden include in flowtable.h as well and leave the two
explicit #includes in ip_input.c and ip_output.c.
2009-06-08 19:57:35 +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
Hiroki Sato
dbe5926046 Fix and add a workaround on an issue of EtherIP packet with reversed
version field sent via gif(4)+if_bridge(4).  The EtherIP
implementation found on FreeBSD 6.1, 6.2, 6.3, 7.0, 7.1, and 7.2 had
an interoperability issue because it sent the incorrect EtherIP
packets and discarded the correct ones.

This change introduces the following two flags to gif(4):

 accept_rev_ethip_ver: accepts both correct EtherIP packets and ones
    with reversed version field, if enabled.  If disabled, the gif
    accepts the correct packets only.  This flag is enabled by
    default.

 send_rev_ethip_ver: sends EtherIP packets with reversed version field
    intentionally, if enabled.  If disabled, the gif sends the correct
    packets only.  This flag is disabled by default.

These flags are stored in struct gif_softc and can be set by
ifconfig(8) on per-interface basis.

Note that this is an incompatible change of EtherIP with the older
FreeBSD releases.  If you need to interoperate older FreeBSD boxes and
new versions after this commit, setting "send_rev_ethip_ver" is
needed.

Reviewed by:	thompsa and rwatson
Spotted by:	Shunsuke SHINOMIYA
PR:		kern/125003
MFC after:	2 weeks
2009-06-07 23:00:40 +00:00
Robert Watson
bcf11e8d00 Move "options MAC" from opt_mac.h to opt_global.h, as it's now in GENERIC
and used in a large number of files, but also because an increasing number
of incorrect uses of MAC calls were sneaking in due to copy-and-paste of
MAC-aware code without the associated opt_mac.h include.

Discussed with:	pjd
2009-06-05 14:55:22 +00:00
Luigi Rizzo
115a40c7bf More cleanup in preparation of ipfw relocation (no actual code change):
+ move ipfw and dummynet hooks declarations to raw_ip.c (definitions
  in ip_var.h) same as for most other global variables.
  This removes some dependencies from ip_input.c;

+ remove the IPFW_LOADED macro, just test ip_fw_chk_ptr directly;

+ remove the DUMMYNET_LOADED macro, just test ip_dn_io_ptr directly;

+ move ip_dn_ruledel_ptr to ip_fw2.c which is the only file using it;

To be merged together with rev 193497

MFC after:	5 days
2009-06-05 13:44:30 +00:00
Sam Leffler
c9dd371765 move ifq_detach from if_detach to if_free; this permits callers to
reference if_snd in the period between detach+free which helps simplify
detach code

Reviewed by:	jhb, rwatson
2009-06-02 18:53:21 +00:00
Robert Watson
d363c61766 Revert a recent netisr2 change: when billing packets to the current
CPU, don't lock the workstream, as its mutexes may not have been
initialized if there are fewer workstreams than CPUs.

Run into by:	hps, ps
2009-06-01 18:38:36 +00:00
Bjoern A. Zeeb
c2c2a7c11e Convert the two dimensional array to be malloced and introduce
an accessor function to get the correct rnh pointer back.

Update netstat to get the correct pointer using kvm_read()
as well.

This not only fixes the ABI problem depending on the kernel
option but also permits the tunable to overwrite the kernel
option at boot time up to MAXFIBS, enlarging the number of
FIBs without having to recompile. So people could just use
GENERIC now.

Reviewed by:	julian, rwatson, zec
X-MFC:		not possible
2009-06-01 15:49:42 +00:00
Robert Watson
ed54411c19 Garbage collect NETISR_POLL and NETISR_POLLMORE, which are no longer
required for options DEVICE_POLLING.

De-fragment the NETISR_ constant space and lower NETISR_MAXPROT from
32 to 16 -- when sizing queue arrays using this compile-time constant,
significant amounts of memory are saved.

Warn on the console when tunable values for netisr are automatically
adjusted during boot due to exceeding limits, invalid values, or as a
result of DEVICE_POLLING.
2009-06-01 15:03:58 +00:00
Robert Watson
d4b5cae49b Reimplement the netisr framework in order to support parallel netisr
threads:

- Support up to one netisr thread per CPU, each processings its own
  workstream, or set of per-protocol queues.  Threads may be bound
  to specific CPUs, or allowed to migrate, based on a global policy.

  In the future it would be desirable to support topology-centric
  policies, such as "one netisr per package".

- Allow each protocol to advertise an ordering policy, which can
  currently be one of:

  NETISR_POLICY_SOURCE: packets must maintain ordering with respect to
    an implicit or explicit source (such as an interface or socket).

  NETISR_POLICY_FLOW: make use of mbuf flow identifiers to place work,
    as well as allowing protocols to provide a flow generation function
    for mbufs without flow identifers (m2flow).  Falls back on
    NETISR_POLICY_SOURCE if now flow ID is available.

  NETISR_POLICY_CPU: allow protocols to inspect and assign a CPU for
    each packet handled by netisr (m2cpuid).

- Provide utility functions for querying the number of workstreams
  being used, as well as a mapping function from workstream to CPU ID,
  which protocols may use in work placement decisions.

- Add explicit interfaces to get and set per-protocol queue limits, and
  get and clear drop counters, which query data or apply changes across
  all workstreams.

- Add a more extensible netisr registration interface, in which
  protocols declare 'struct netisr_handler' structures for each
  registered NETISR_ type.  These include name, handler function,
  optional mbuf to flow ID function, optional mbuf to CPU ID function,
  queue limit, and ordering policy.  Padding is present to allow these
  to be expanded in the future.  If no queue limit is declared, then
  a default is used.

- Queue limits are now per-workstream, and raised from the previous
  IFQ_MAXLEN default of 50 to 256.

- All protocols are updated to use the new registration interface, and
  with the exception of netnatm, default queue limits.  Most protocols
  register as NETISR_POLICY_SOURCE, except IPv4 and IPv6, which use
  NETISR_POLICY_FLOW, and will therefore take advantage of driver-
  generated flow IDs if present.

- Formalize a non-packet based interface between interface polling and
  the netisr, rather than having polling pretend to be two protocols.
  Provide two explicit hooks in the netisr worker for start and end
  events for runs: netisr_poll() and netisr_pollmore(), as well as a
  function, netisr_sched_poll(), to allow the polling code to schedule
  netisr execution.  DEVICE_POLLING still embeds single-netisr
  assumptions in its implementation, so for now if it is compiled into
  the kernel, a single and un-bound netisr thread is enforced
  regardless of tunable configuration.

In the default configuration, the new netisr implementation maintains
the same basic assumptions as the previous implementation: a single,
un-bound worker thread processes all deferred work, and direct dispatch
is enabled by default wherever possible.

Performance measurement shows a marginal performance improvement over
the old implementation due to the use of batched dequeue.

An rmlock is used to synchronize use and registration/unregistration
using the framework; currently, synchronized use is disabled
(replicating current netisr policy) due to a measurable 3%-6% hit in
ping-pong micro-benchmarking.  It will be enabled once further rmlock
optimization has taken place.  However, in practice, netisrs are
rarely registered or unregistered at runtime.

A new man page for netisr will follow, but since one doesn't currently
exist, it hasn't been updated.

This change is not appropriate for MFC, although the polling shutdown
handler should be merged to 7-STABLE.

Bump __FreeBSD_version.

Reviewed by:	bz
2009-06-01 10:41:38 +00:00
Marko Zec
feb08d06b9 Introduce an interm userland-kernel API for creating vnets and
assigning ifnets from one vnet to another.  Deletion of vnets is not
yet supported.

The interface is implemented as an ioctl extension so that no syscalls
had to be introduced.  This should be acceptable given that the new
interface will be used for a short / interim period only, until the
new jail management framwork gains the capability of managing vnets.
This method for managing vimages / vnets has been in use for the past
7 years without any observable issues.

The userland tool to be used in conjunction with the interim API can be
found in p4: //depot/projects/vimage-commit2/src/usr.sbin/vimage/... and
will most probably never get commited to svn.

While here, bump copyright notices in kern_vimage.c and vimage.h to
cover work done in year 2009.

Approved by:	julian (mentor)
Discussed with:	bz, rwatson
2009-05-31 12:10:04 +00:00
Attilio Rao
1abcdbd127 When user_frac in the polling subsystem is low it is going to busy the
CPU for too long period than necessary.  Additively, interfaces are kept
polled (in the tick) even if no more packets are available.
In order to avoid such situations a new generic mechanism can be
implemented in proactive way, keeping track of the time spent on any
packet and fragmenting the time for any tick, stopping the processing
as soon as possible.

In order to implement such mechanism, the polling handler needs to
change, returning the number of packets processed.
While the intended logic is not part of this patch, the polling KPI is
broken by this commit, adding an int return value and the new flag
IFCAP_POLLING_NOCOUNT (which will signal that the return value is
meaningless for the installed handler and checking should be skipped).

Bump __FreeBSD_version in order to signal such situation.

Reviewed by:	emaste
Sponsored by:	Sandvine Incorporated
2009-05-30 15:14:44 +00:00
Robert Watson
1a109c1cb0 Make the rmlock(9) interface a bit more like the rwlock(9) interface:
- Add rm_init_flags() and accept extended options only for that variation.
- Add a flags space specifically for rm_init_flags(), rather than borrowing
  the lock_init() flag space.
- Define flag RM_RECURSE to use instead of LO_RECURSABLE.
- Define flag RM_NOWITNESS to allow an rmlock to be exempt from WITNESS
  checking; this wasn't possible previously as rm_init() always passed
  LO_WITNESS when initializing an rmlock's struct lock.
- Add RM_SYSINIT_FLAGS().
- Rename embedded mutex in rmlocks to make it more obvious what it is.
- Update consumers.
- Update man page.
2009-05-29 10:52:37 +00:00
Jamie Gritton
0304c73163 Add hierarchical jails. A jail may further virtualize its environment
by creating a child jail, which is visible to that jail and to any
parent jails.  Child jails may be restricted more than their parents,
but never less.  Jail names reflect this hierarchy, being MIB-style
dot-separated strings.

Every thread now points to a jail, the default being prison0, which
contains information about the physical system.  Prison0's root
directory is the same as rootvnode; its hostname is the same as the
global hostname, and its securelevel replaces the global securelevel.
Note that the variable "securelevel" has actually gone away, which
should not cause any problems for code that properly uses
securelevel_gt() and securelevel_ge().

Some jail-related permissions that were kept in global variables and
set via sysctls are now per-jail settings.  The sysctls still exist for
backward compatibility, used only by the now-deprecated jail(2) system
call.

Approved by:	bz (mentor)
2009-05-27 14:11:23 +00:00
Sam Leffler
5ce8d9708c rev bpf attach/detach event api to include the dlt 2009-05-25 16:34:35 +00:00
Marko Zec
37f17770e0 V_irtualize the if_clone framework, thus allowing for clonable ifnets
to optionally have overlapping unit numbers if attached in different
vnets.

At this stage if_loop is the only clonable ifnet class that has been
extended to allow for such overlapping allocation of unit numbers, i.e.
in each vnet it is possible to have a lo0 interface.  Other clonable ifnet
classes remain to operate with traditional semantics, i.e. each instance
of a clonable ifnet will be assigned a globally unique unit number,
regardless in which vnet such an ifnet becomes instantiated.

While here, garbage collect unused _lo_list field in struct vnet_net,
as well as improve indentation for #defines in sys/net/vnet.h.

The layout of struct vnet_net has changed, therefore bump
__FreeBSD_version.

This change has no functional impact on nooptions VIMAGE kernel builds.

Reviewed by:	bz, brooks
Approved by:	julian (mentor)
2009-05-23 21:43:44 +00:00
Marko Zec
67da1f3d8d Set ifp->if_afdata_initialized to 0 while holding IF_AFDATA_LOCK on ifp,
not after the lock has been released.

Reviewed by:	bz
Discussed with:	rwatson
2009-05-22 22:22:21 +00:00
Marko Zec
e0c14af9b3 Introduce the if_vmove() function, which will be used in the future
for reassigning ifnets from one vnet to another.

if_vmove() works by calling a restricted subset of actions normally
executed by if_detach() on an ifnet in the current vnet, and then
switches to the target vnet and executes an appropriate subset of
if_attach() actions there.

if_attach() and if_detach() have become wrapper functions around
if_attach_internal() and if_detach_internal(), where the later
variants have an additional argument, a flag indicating whether a
full attach or detach sequence is to be executed, or only a
restricted subset suitable for moving an ifnet from one vnet to
another.  Hence, if_vmove() will not call if_detach() and if_attach()
directly, but will call the if_detach_internal() and
if_attach_internal() variants instead, with the vmove flag set.

While here, staticize ifnet_setbyindex() since it is not referenced
from outside of sys/net/if.c.

Also rename ifccnt field in struct vimage to ifcnt, and do some minor
whitespace garbage collection where appropriate.

This change should have no functional impact on nooptions VIMAGE kernel
builds.

Reviewed by:	bz, rwatson, brooks?
Approved by:	julian (mentor)
2009-05-22 22:09:00 +00:00
Qing Li
c9d763bf41 When an interface address is removed and the last prefix
route is also being deleted, the link-layer address table
(arp or nd6) will flush those L2 llinfo entries that match
the removed prefix.

Reviewed by:	kmacy
2009-05-20 21:07:15 +00:00
Sam Leffler
b743c31009 add bpf_track eventhandler for monitoring bpf taps attached/detached
Reviewed by:	csjp
2009-05-18 17:18:40 +00:00
Robert Watson
a765f96051 Garbage collect unused NETISR_{ATM,NETGRAPH,PPP} netisr constants. 2009-05-18 10:33:23 +00:00
Robert Watson
2f120c90a7 Garbage collect now-unused NETISR_FORCEQUEUE, which overrode the global
direct dispatch policy for specific protocols (NETISR_USB).  We leave
the additional 'flags' argument to netisr_register() for the time being,
even though it is no longer required.
2009-05-13 17:22:33 +00:00
Robert Watson
270b609935 Remove now-unused NETISR_USB. 2009-05-13 17:17:05 +00:00
Marko Zec
21ca7b57bd Change the curvnet variable from a global const struct vnet *,
previously always pointing to the default vnet context, to a
dynamically changing thread-local one.  The currvnet context
should be set on entry to networking code via CURVNET_SET() macros,
and reverted to previous state via CURVNET_RESTORE().  Recursions
on curvnet are permitted, though strongly discuouraged.

This change should have no functional impact on nooptions VIMAGE
kernel builds, where CURVNET_* macros expand to whitespace.

The curthread->td_vnet (aka curvnet) variable's purpose is to be an
indicator of the vnet context in which the current network-related
operation takes place, in case we cannot deduce the current vnet
context from any other source, such as by looking at mbuf's
m->m_pkthdr.rcvif->if_vnet, sockets's so->so_vnet etc.  Moreover, so
far curvnet has turned out to be an invaluable consistency checking
aid: it helps to catch cases when sockets, ifnets or any other
vnet-aware structures may have leaked from one vnet to another.

The exact placement of the CURVNET_SET() / CURVNET_RESTORE() macros
was a result of an empirical iterative process, whith an aim to
reduce recursions on CURVNET_SET() to a minimum, while still reducing
the scope of CURVNET_SET() to networking only operations - the
alternative would be calling CURVNET_SET() on each system call entry.
In general, curvnet has to be set in three typicall cases: when
processing socket-related requests from userspace or from within the
kernel; when processing inbound traffic flowing from device drivers
to upper layers of the networking stack, and when executing
timer-driven networking functions.

This change also introduces a DDB subcommand to show the list of all
vnet instances.

Approved by:	julian (mentor)
2009-05-05 10:56:12 +00:00
Marko Zec
5f416f8e84 Make indentation more uniform accross vnet container structs.
This is a purely cosmetic / NOP change.

Reviewed by:	bz
Approved by:	julian (mentor)
Verified by:	svn diff -x -w producing no output
2009-05-02 08:16:26 +00:00
Marko Zec
d7fcc52895 Unbreak options VIMAGE + nooptions INVARIANTS kernel builds.
Submitted by:	julian
Approved by:	julian (mentor)
2009-05-02 05:02:28 +00:00
Andrew Thompson
3f11aba75f Reorder the bridge add and delete routines to avoid calling ifpromisc() with
the bridge lock held.
2009-05-01 19:46:42 +00:00
Andrew Thompson
5c6026e91f Use the flowid if its available for selecting the tx port. 2009-04-30 14:25:44 +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
Kip Macy
6e3513f523 replace IFQ_ENQUEUE + if_start with if_transmit 2009-04-27 22:46:26 +00:00
Kip Macy
2635206d3a replace IFQ_HANDOFF with if_transmit 2009-04-27 22:45:56 +00:00
Kip Macy
68bd638360 remove gratuitous memory barrier, a remnant of unified L2 / L3 2009-04-27 22:45:19 +00:00
Kip Macy
1bc27a1ce3 remove call to IFQ_HANDOFF is it called by if_transmit in the default case
and doing so allows the ifnet driver to define its own queueing mechanism
2009-04-27 22:44:26 +00:00
Sam Leffler
5d3220403f use if_transmit intead of direct frobbing of the if_snd q; this is no
longer allowed

Identified by:	rwatson
Reviewed by:	kmacy
2009-04-27 22:06:49 +00:00
Marko Zec
093f25f8c8 In preparation for turning on options VIMAGE in next commits,
rearrange / replace / adjust several INIT_VNET_* initializer
macros, all of which currently resolve to whitespace.

Reviewed by:	bz (an older version of the patch)
Approved by:	julian (mentor)
2009-04-26 22:06:42 +00:00
Robert Watson
8bd015a1ca As with ifnet_byindex_ref(), don't return IFF_DYING interfaces from
ifunit_ref().  ifunit() continues to return them.

MFC after:	3 weeks
2009-04-23 15:56:01 +00:00
Robert Watson
6064c5d362 Add ifunit_ref(), a version of ifunit(), that returns not just an
interface pointer, but also a reference to it.

Modify ifioctl() to use ifunit_ref(), holding the reference until
all ioctls, etc, have completed.

This closes a class of reader-writer races in which interfaces
could be removed during long-running ioctls, leading to crashes.
Many other consumers of ifunit() should now use ifunit_ref() to
avoid similar races.

MFC after:	3 weeks
2009-04-23 13:08:47 +00:00
Robert Watson
111c6b617b During if_detach(), invoke if_dead() to set the ifnet's function
pointers to "dead" implementations that no-op rather than invoking
the device driver.  This would generally be unexpected and
possibly quite badly handled by most device drivers after
if_detach() has completed.

Reviewed by:	bms
MFC after:	3 weeks
2009-04-23 11:51:53 +00:00
Robert Watson
d6f157ea9a Move portions of data structure initialization from if_attach() to
if_alloc(), and portions of data structure destruction from if_detach()
to if_free().  These changes leave more of the struct ifnet in a
safe-to-access condition between alloc and attach, and between detach
and free, and focus on attach/detach as stack usage events rather than
data structure initialization.

Affected fields include the linkstate task queue, if_afdata lock,
address lists, kqueue state, and MAC labels.  ifq_attach() ifq_detach()
are not moved as ifq_attach() may use a queue length set by the device
driver between if_alloc() and if_attach().

MFC after:	3 weeks
2009-04-23 10:59:40 +00:00