Commit Graph

270 Commits

Author SHA1 Message Date
Alexander Kabaev
151ba7933a Do pass removing some write-only variables from the kernel.
This reduces noise when kernel is compiled by newer GCC versions,
such as one used by external toolchain ports.

Reviewed by: kib, andrew(sys/arm and sys/arm64), emaste(partial), erj(partial)
Reviewed by: jhb (sys/dev/pci/* sys/kern/vfs_aio.c and sys/kern/kern_synch.c)
Differential Revision: https://reviews.freebsd.org/D10385
2017-12-25 04:48:39 +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
Alan Somers
559b42968c Constrain IPv6 routes to single FIBs when net.add_addr_allfibs=0
sys/netinet6/icmp6.c
	Use the interface's FIB for source address selection in ICMPv6 error
	responses.

sys/netinet6/in6.c
	In in6_newaddrmsg, announce arrival of local addresses on the
	interface's FIB only.  In in6_lltable_rtcheck, use a per-fib ND6
	cache instead of a single cache.

sys/netinet6/in6_src.c
	In in6_selectsrc, use the caller's fib instead of the default fib.
	In in6_selectsrc_socket, remove a superfluous check.

sys/netinet6/nd6.c
	In nd6_lle_event, use the interface's fib for routing socket
	messages.  In nd6_is_new_addr_neighbor, check all FIBs when trying
	to determine whether an address is a neighbor.  Also, simplify the
	code for point to point interfaces.

sys/netinet6/nd6.h
sys/netinet6/nd6.c
sys/netinet6/nd6_rtr.c
	Make defrouter_select fib-aware, and make all of its callers pass in
	the interface fib.

sys/netinet6/nd6_nbr.c
	When inputting a Neighbor Solicitation packet, consider the
	interface fib instead of the default fib for DAD.  Output NS and
	Neighbor Advertisement packets on the correct fib.

sys/netinet6/nd6_rtr.c
	Allow installing the same host route on different interfaces in
	different FIBs.  If rt_add_addr_allfibs=0, only install or delete
	the prefix route on the interface fib.

tests/sys/netinet/fibs_test.sh
	Clear some expected failures, but add a skip for the newly revealed
	BUG217871.

PR:		196361
Submitted by:	Erick Turnquist <jhujhiti@adjectivism.org>
Reported by:	Jason Healy <jhealy@logn.net>
Reviewed by:	asomers
MFC after:	3 weeks
Sponsored by:	Spectra Logic Corp
Differential Revision:	https://reviews.freebsd.org/D9451
2017-03-17 16:50:37 +00:00
Andriy Voskoboinyk
2bbd06fc33 Garbage collect IFT_IEEE80211 (but leave the define for possible reuse)
This interface type ("a parent interface of wlanX") is not used since
r287197

Reviewed by:	adrian, glebius
Differential Revision:	https://reviews.freebsd.org/D9308
2017-01-28 17:08:40 +00:00
Mark Johnston
8cd3b2042c Release the ND6 list lock before making a prefix off-link in nd6_timer().
Reported by:	Jim <BM-2cWfdfG5CJsquqkJyry7hZT9LypbSEWEkQ@bitmessage.ch>
X-MFC With:	r306829
2017-01-08 18:46:00 +00:00
Mark Johnston
d748f7efcd Lock the ND prefix list and add refcounting for prefixes.
This change extends the nd6 lock to protect the ND prefix list as well
as the list of advertising routers associated with each prefix. To handle
cases where the nd6 lock must be dropped while iterating over either the
prefix or default router lists, a generation counter is used to track
modifications to the lists. Additionally, a new mutex is used to serialize
prefix on-link/off-link transitions. This mutex must be acquired before
the nd6 lock and is held while updating the routing table in
nd6_prefix_onlink() and nd6_prefix_offlink().

Reviewed by:	ae, tuexen (SCTP bits)
Tested by:	Jason Wolfe <jason@llnw.com>,
		Larry Rosenman <ler@lerctr.org>
MFC after:	2 months
Differential Revision:	https://reviews.freebsd.org/D8125
2016-10-07 21:10:53 +00:00
Mark Johnston
f7d91d8cdd Use a const reference to prefixes in nd6_is_new_addr_neighbor().
MFC after:	1 week
2016-10-07 00:26:36 +00:00
Mark Johnston
0bbf244e9f Rename ndpr_refcnt to ndpr_addrcnt.
This field counts derived addresses and is not a true refcount for prefix
objects, so the previous name was misleading.

MFC after:	1 week
2016-09-24 01:14:25 +00:00
Mike Karels
ea17754c5a Fix per-connection L2 caching in fast path
r301217 re-added per-connection L2 caching from a previous change,
but it omitted caching in the fast path.  Add it.

Reviewed By: gallatin
Approved by: gnn (mentor)
Differential Revision: https://reviews.freebsd.org/D7239
2016-07-22 02:11:49 +00:00
Bjoern A. Zeeb
89856f7e2d Get closer to a VIMAGE network stack teardown from top to bottom rather
than removing the network interfaces first. This change is rather larger
and convoluted as the ordering requirements cannot be separated.

Move the pfil(9) framework to SI_SUB_PROTO_PFIL, move Firewalls and
related modules to their own SI_SUB_PROTO_FIREWALL.
Move initialization of "physical" interfaces to SI_SUB_DRIVERS,
move virtual (cloned) interfaces to SI_SUB_PSEUDO.
Move Multicast to SI_SUB_PROTO_MC.

Re-work parts of multicast initialisation and teardown, not taking the
huge amount of memory into account if used as a module yet.

For interface teardown we try to do as many of them as we can on
SI_SUB_INIT_IF, but for some this makes no sense, e.g., when tunnelling
over a higher layer protocol such as IP. In that case the interface
has to go along (or before) the higher layer protocol is shutdown.

Kernel hhooks need to go last on teardown as they may be used at various
higher layers and we cannot remove them before we cleaned up the higher
layers.

For interface teardown there are multiple paths:
(a) a cloned interface is destroyed (inside a VIMAGE or in the base system),
(b) any interface is moved from a virtual network stack to a different
network stack ("vmove"), or (c) a virtual network stack is being shut down.
All code paths go through if_detach_internal() where we, depending on the
vmove flag or the vnet state, make a decision on how much to shut down;
in case we are destroying a VNET the individual protocol layers will
cleanup their own parts thus we cannot do so again for each interface as
we end up with, e.g., double-frees, destroying locks twice or acquiring
already destroyed locks.
When calling into protocol cleanups we equally have to tell them
whether they need to detach upper layer protocols ("ulp") or not
(e.g., in6_ifdetach()).

Provide or enahnce helper functions to do proper cleanup at a protocol
rather than at an interface level.

Approved by:		re (hrs)
Obtained from:		projects/vnet
Reviewed by:		gnn, jhb
Sponsored by:		The FreeBSD Foundation
MFC after:		2 weeks
Differential Revision:	https://reviews.freebsd.org/D6747
2016-06-21 13:48:49 +00:00
Bjoern A. Zeeb
99a0c4062d Move the callout_reset() to the end of the work not having it stick
before we do anything.

Obtained from:	projects/vnet
MFC after:	2 week
Sponsored by:	The FreeBSD Foundation
2016-06-06 14:01:09 +00:00
George V. Neville-Neil
6d76822688 This change re-adds L2 caching for TCP and UDP, as originally added in D4306
but removed due to other changes in the system. Restore the llentry pointer
to the "struct route", and use it to cache the L2 lookup (ARP or ND6) as
appropriate.

Submitted by:	Mike Karels
Differential Revision:	https://reviews.freebsd.org/D6262
2016-06-02 17:51:29 +00:00
Mark Johnston
65fdf52123 Mark the prefix and default router list sysctl handlers MPSAFE.
MFC after:	2 weeks
2016-05-23 20:18:11 +00:00
Mark Johnston
cc51be7b81 Acquire the nd6 lock in the prefix list sysctl handler.
The nd6 lock will be used to synchronize access to the NDP prefix list.

MFC after:	2 weeks
Tested by:	Jason Wolfe (as part of a larger change)
2016-05-23 20:15:08 +00:00
Mark Johnston
5e0a6f31e5 Move IPv6 malloc tag definitions into the IPv6 code. 2016-05-20 04:45:08 +00:00
Mark Johnston
df890b8e73 Remove obsolescent comments from nd6_purge().
MFC after:	1 week
2016-05-09 23:43:12 +00:00
Pedro F. Giffuni
a4641f4eaa sys/net*: minor spelling fixes.
No functional change.
2016-05-03 18:05:43 +00:00
Luiz Otavio O Souza
b0ab3725db Fixes the comment to reflect the code.
Sponsored by:	Rubicon Communications (Netgate)
2016-04-25 23:12:39 +00:00
Mark Johnston
435bece4c5 Modify nd6_llinfo_timer() to acquire the nd6 lock before the LLE lock.
When expiring a neighbour cache entry we may need to look up the associated
default router, which requires the nd6 read lock. To avoid an LOR, the nd6
lock should be acquired first.

X-MFC-With:	r296063
Tested by:	Larry Rosenman <ler@lerctr.org> (previous revision)
2016-03-29 19:23:00 +00:00
Bjoern A. Zeeb
9901091eba Mfp4 @180378:
Factor out nd6 and in6_attach initialization to their own files.
  Also move destruction into those files though still called from
  the central initialization.

  Sponsored by:	CK Software GmbH
Sponsored by:	The FreeBSD Foundation
MFC after:	2 weeks
Reviewed by:	gnn
Differential Revision:	https://reviews.freebsd.org/D5033
2016-03-22 15:43:47 +00:00
Mark Johnston
4de485fe5f Lock the NDP default router list and count defrouter references.
This addresses a number of race conditions that can cause crashes as a
result of unsynchronized access to the list.

PR:		206904
Tested by:	Larry Rosenman <ler@lerctr.org>,
		Kevin Bowling <kevin.bowling@kev009.com>
MFC after:	2 months
Differential Revision: https://reviews.freebsd.org/D5315
2016-02-25 20:12:05 +00:00
Mark Johnston
01869be58e Rename the flags field of struct nd_defrouter to "raflags".
This field contains the flags inherited from the corresponding router
advertisement message and is not for storing private state.

MFC after:	1 week
2016-02-12 21:15:57 +00:00
Mark Johnston
baebd3e54f Remove superfluous return statements from the neighbour discovery code.
MFC after:	1 week
2016-02-12 20:55:22 +00:00
Mark Johnston
fc31564185 Fix style around allocations from M_IP6NDP.
- Don't cast the return value of malloc(9).
- Use M_ZERO instead of explicitly calling bzero(9).

MFC after:	1 week
2016-02-12 20:52:53 +00:00
Mark Johnston
97dca6a207 Remove some unreferenced NDP debug variable definitions.
MFC after:	1 week
2016-02-12 20:46:53 +00:00
Alexander V. Chernikov
9a1b64d5a0 Add rib_lookup_info() to provide API for retrieving individual route
entries data in unified format.

There are control plane functions that require information other than
  just next-hop data (e.g. individual rtentry fields like flags or
  prefix/mask). Given that the goal is to avoid rte reference/refcounting,
  re-use rt_addrinfo structure to store most rte fields. If caller wants
  to retrieve key/mask or gateway (which are sockaddrs and are allocated
  separately), it needs to provide sufficient-sized sockaddrs structures
  w/ ther pointers saved in passed rt_addrinfo.

Convert:
  * lltable new records checks (in_lltable_rtcheck(),
    nd6_is_new_addr_neighbor().
  * rtsock pre-add/change route check.
  * IPv6 NS ND-proxy check (RADIX_MPATH code was eliminated because
     1) we don't support RTF_ANNOUNCE ND-proxy for networks and there should
       not be multiple host routes for such hosts 2) if we have multiple
       routes we should inspect them (which is not done). 3) the entire idea
       of abusing KRT as storage for ND proxy seems odd. Userland programs
       should be used for that purpose).
2016-01-04 15:03:20 +00:00
Alexander V. Chernikov
4fb3a8208c Implement interface link header precomputation API.
Add if_requestencap() interface method which is capable of calculating
  various link headers for given interface. Right now there is support
  for INET/INET6/ARP llheader calculation (IFENCAP_LL type request).
  Other types are planned to support more complex calculation
  (L2 multipath lagg nexthops, tunnel encap nexthops, etc..).

Reshape 'struct route' to be able to pass additional data (with is length)
  to prepend to mbuf.

These two changes permits routing code to pass pre-calculated nexthop data
  (like L2 header for route w/gateway) down to the stack eliminating the
  need for other lookups. It also brings us closer to more complex scenarios
  like transparently handling MPLS nexthops and tunnel interfaces.
  Last, but not least, it removes layering violation introduced by flowtable
  code (ro_lle) and simplifies handling of existing if_output consumers.

ARP/ND changes:
Make arp/ndp stack pre-calculate link header upon installing/updating lle
  record. Interface link address change are handled by re-calculating
  headers for all lles based on if_lladdr event. After these changes,
  arpresolve()/nd6_resolve() returns full pre-calculated header for
  supported interfaces thus simplifying if_output().
Move these lookups to separate ether_resolve_addr() function which ether
  returs error or fully-prepared link header. Add <arp|nd6_>resolve_addr()
  compat versions to return link addresses instead of pre-calculated data.

BPF changes:
Raw bpf writes occupied _two_ cases: AF_UNSPEC and pseudo_AF_HDRCMPLT.
Despite the naming, both of there have ther header "complete". The only
  difference is that interface source mac has to be filled by OS for
  AF_UNSPEC (controlled via BIOCGHDRCMPLT). This logic has to stay inside
  BPF and not pollute if_output() routines. Convert BPF to pass prepend data
  via new 'struct route' mechanism. Note that it does not change
  non-optimized if_output(): ro_prepend handling is purely optional.
Side note: hackish pseudo_AF_HDRCMPLT is supported for ethernet and FDDI.
  It is not needed for ethernet anymore. The only remaining FDDI user is
  dev/pdq mostly untouched since 2007. FDDI support was eliminated from
  OpenBSD in 2013 (sys/net/if_fddisubr.c rev 1.65).

Flowtable changes:
  Flowtable violates layering by saving (and not correctly managing)
  rtes/lles. Instead of passing lle pointer, pass pointer to pre-calculated
  header data from that lle.

Differential Revision:	https://reviews.freebsd.org/D4102
2015-12-31 05:03:27 +00:00
Steven Hartland
d6e82913c1 Revert r292275 & r292379
glebius has concerns about these changes so reverting those can be discussed
and addressed.

Sponsored by:	Multiplay
2015-12-17 14:41:30 +00:00
Steven Hartland
3a909afe8e Fix issues introduced by r292275
* Fix panic for etherswitches which don't have a LLADDR.
* Disabled DELAY in unsolicited NDA, which needs further work.
* Fixed missing DELAY in carp_send_na.
* style(9) fix.

Reported by:	kp & melifaro
X-MFC-With:	r292275
MFC after:	1 month
Sponsored by:	Multiplay
2015-12-16 22:26:28 +00:00
Alexander V. Chernikov
427c2f4ef0 Provide additional lle data in IPv6 lltable dump used by ndp(8).
Before the change, things like lle state were queried via
  SIOCGNBRINFO_IN6 by ndp(8) for _each_ lle entry in dump.
This ioctl was added in 1999, probably to avoid touching rtsock code.

This change maps SIOCGNBRINFO_IN6 data to standard rtsock dump the
 following way:
  expire (already) maps to rtm_rmx.rmx_expire
  isrouter -> rtm_flags & RTF_GATEWAY
  asked -> rtm_rmx.rmx_pksent
  state -> rtm_rmx.rmx_state (maps to rmx_weight via define)

Reviewed by:	ae
2015-12-16 10:14:16 +00:00
Steven Hartland
52e53e2de0 Fix lagg failover due to missing notifications
When using lagg failover mode neither Gratuitous ARP (IPv4) or Unsolicited
Neighbour Advertisements (IPv6) are sent to notify other nodes that the
address may have moved.

This results is slow failover, dropped packets and network outages for the
lagg interface when the primary link goes down.

We now use the new if_link_state_change_cond with the force param set to
allow lagg to force through link state changes and hence fire a
ifnet_link_event which are now monitored by rip and nd6.

Upon receiving these events each protocol trigger the relevant
notifications:
* inet4 => Gratuitous ARP
* inet6 => Unsolicited Neighbour Announce

This also fixes the carp IPv6 NA's that stopped working after r251584 which
added the ipv6_route__llma route.

The new behavour can be controlled using the sysctls:
* net.link.ether.inet.arp_on_link
* net.inet6.icmp6.nd6_on_link

Also removed unused param from lagg_port_state and added descriptions for the
sysctls while here.

PR:		156226
MFC after:	1 month
Sponsored by:	Multiplay
Differential Revision:	https://reviews.freebsd.org/D4111
2015-12-15 16:02:11 +00:00
Kristof Provost
7e037c12f2 inet6: Do not assume every interface has ip6 enabled.
Certain interfaces (e.g. pfsync0) do not have ip6 addresses (in other words,
ifp->if_afdata[AF_INET6] is NULL). Ensure we don't panic when the MTU is
updated.

pfsync interfaces will never have ip6 support, because it's explicitly disabled
in in6_domifattach().

PR:		205194
Reviewed by:	melifaro, hrs
Differential Revision:	https://reviews.freebsd.org/D4522
2015-12-14 19:44:49 +00:00
Alexander V. Chernikov
12cb7521c2 Remove LLE read lock from IPv6 fast path.
LLE structure is mostly unchanged during its lifecycle: there are only 2
things relevant for fast path lookup code:
1) link-level address change. Since r286722, these updates are performed
  under AFDATA WLOCK.
2) Some sort of feedback indicating that this particular entry is used so
  we send NS to perform reachability verification instead of expiring entry.
  The only signal that is needed from fast path is something like binary
  yes/no.
The latter is solved by the following changes:

Special r_skip_req (introduced in D3688) value is used for fast path feedback.
  It is read lockless by fast path, but updated under req_mutex mutex. If this
  field is non-zero, then fast path will acquire lock and set it back to 0.

After transitioning to STALE state, callout timer is armed to run each
  V_nd6_delay seconds to make sure that if packet was transmitted at the start
  of given interval, we would be able to switch to PROBE state in V_nd6_delay
  seconds as user expects.
(in STALE state) timer is rescheduled until original V_nd6_gctimer expires
  keeping lle in STALE state (remaining timer value stored in lle_remtime).
(in STALE state) timer is rescheduled if packet was transmitted less that
  V_nd6_delay seconds ago to make sure we transition to PROBE state exactly
  after V_n6_delay seconds.

As a result, all packets towards lle in REACHABLE/STALE/PROBE states are handled
  by fast path without acquiring lle read lock.

Differential Revision:		https://reviews.freebsd.org/D3780
2015-12-13 07:39:49 +00:00
Alexander V. Chernikov
e8b0643eee Add new rt_foreach_fib_walk_del() function for deleting route entries
by filter function instead of picking into routing table details in
  each consumer.
Remove now-unused rt_expunge() (eliminating last external RTF_RNH_LOCKED
 user).
This simplifies future nexthops/mulitipath changes and rtrequest1_fib()
  locking refactoring.

Actual changes:
Add "rt_chain" field to permit rte grouping while doing batched delete
  from routing table (thus growing rte 200->208 on amd64).
Add "rti_filter" /  "rti_filterdata" / "rti_spare" fields to rt_addrinfo
  to pass filter function to various routing subsystems in standard way.
Convert all rt_expunge() customers to new rt_addinfo-based api and eliminate
  rt_expunge().
2015-11-30 05:51:14 +00:00
Alexander V. Chernikov
637670e77e Bring back the ability of passing cached route via nd6_output_ifp(). 2015-11-15 16:02:22 +00:00
Randall Stewart
7c4676ddee This fixes several places where callout_stops return is examined. The
new return codes of -1 were mistakenly being considered "true". Callout_stop
now returns -1 to indicate the callout had either already completed or
was not running and 0 to indicate it could not be stopped.  Also update
the manual page to make it more consistent no non-zero in the callout_stop
or callout_reset descriptions.

MFC after:	1 Month with associated callout change.
2015-11-13 22:51:35 +00:00
Alexander V. Chernikov
ddd208f7ad Unify setting lladdr for AF_INET[6]. 2015-11-07 11:12:00 +00:00
Alexander V. Chernikov
ab415c8307 Invoke lle_event for new entry iff it has lladdr set. 2015-10-04 19:10:27 +00:00
Alexander V. Chernikov
7503e0c783 Simplify if (lladdr) condition in nd6_cache_lladdr():
For case (7) (new entry) nothing has to be done except lle_event.
  Invoke this event directly from "create new lle" code block.
  For case (4) (existing entry, same mac) useless mac update was performed,
  along with LLENTRY_RESOLVED lle_event. There was no sense in doing that,
  since nothing really had changed. Simply avoid this condition instead.
  Given that, condition was simplified to (3),(5) states which can be merged
  with previous block.
2015-10-04 12:42:07 +00:00
Alexander V. Chernikov
9b420b3da4 Eliminate nd6_llinfo_settimer(). All consumers were converted to
use nd6_llinfo_settimer_locked() in r216022.
Make nd6_llinfo_settimer_locked() static: last external consumer was
converted in r288124.
2015-10-04 08:33:16 +00:00
Alexander V. Chernikov
c0b8aeae2d Add __noinline attribute to several functions to ease dtrace instrumentation 2015-10-04 08:21:15 +00:00
Alexander V. Chernikov
06a60e4bb0 Fix condition for nd6_llinfo_getholdsrc() introduced in r287484.
Effectively it always returned NULL so SAS was always performed and
  sometimes the result might have been different.

Fix state machine change accidentally introduced in r287985:
  state (4) inside nd6_cache_lladdr() (existing entry got nd message
  with the same lladdress) started to cause lle state transition to STALE
  instead of no-action.
2015-10-04 07:02:17 +00:00
Hiroki Sato
6401c828ce - Schedule DAD for IN6_IFF_TENTATIVE addresses in nd6_timer(). This
catches cases that DAD probes cannot be sent because of
  IFF_UP && !IFF_DRV_RUNNING.

- nd6_dad_starttimer() now calls nd6_dad_ns_output(), instead of
  calling it before nd6_dad_starttimer().

- Do not release an entry in dadq when a duplicate entry is being
  added.
2015-10-03 12:09:12 +00:00
Alexander V. Chernikov
1558cb2448 Eliminate nd6_nud_hint() and its TCP bindings.
Initially function was introduced in r53541 (KAME initial commit) to
  "provide hints from upper layer protocols that indicate a connection
  is making "forward progress"" (quote from RFC 2461 7.3.1 Reachability
  Confirmation).
However, it was converted to do nothing (e.g. just return) in r122922
  (tcp_hostcache implementation) back in 2003. Some defines were moved
  to tcp_var.h in r169541. Then, it was broken (for non-corner cases)
  by r186119 (L2<>L3 split) in 2008 (NULL ifp in nd6_lookup). So,
  right now this code is broken and has no "real" base users.

Differential Revision:	https://reviews.freebsd.org/D3699
2015-09-27 05:29:34 +00:00
Alexander V. Chernikov
f506d933b5 Use standard lle LLE_EXCLUSIVE request flags instead of
its redefined version.
2015-09-22 20:45:04 +00:00
Alexander V. Chernikov
aa5f023eaf Unify nd6 state switching by using newly-created nd6_llinfo_setstate()
function. The change is mostly mechanical with the following exception:
Last piece of nd6_resolve_slow() was refactored: ND6_LLINFO_PERMANENT
  condition was removed as always-true, explicit ND6_LLINFO_NOSTATE ->
  ND6_LLINFO_INCOMPLETE state transition was removed as duplicate.

Reviewed by:	ae
Sponsored by:	Yandex LLC
2015-09-21 11:19:53 +00:00
Alexander V. Chernikov
1496229a91 Add "stale" timer back to nd6_cache_lladdr().
Setting timer was accidentally removed in r276844 due to misleading
  comment on its meaningless. Add it back to restore proper behaviour.
2015-09-21 10:24:34 +00:00
Alexander V. Chernikov
501adf0140 Cleanup nd6_cache_lladdr(). No functional changes.
* Since new extries are now allocated explicitly, fill in
  all the necessary fields for lle _before_ attaching it to the table.
* Remove ND6_LLINFO_INCOMPLETE check which was unused even in
  first KAME merge (r53541).
* After that, the only new state that function can set, was
  ND6_LLINFO_STALE. Given everything above, simplify logic besides
  do_update and is_newentry.
* Fix nd_resolve() comment.
2015-09-19 11:50:02 +00:00
Alexander V. Chernikov
41a31e783e * Simplify logic besides llchange variable.
* Refresh nd6_is_router() comment.
2015-09-18 07:18:10 +00:00
Alexander V. Chernikov
1fe201c322 Simplify the way of attaching IPv6 link-layer header.
Problem description:
How do we currently perform layer 2 resolution and header imposition:

For IPv4 we have the following chain:
  ip_output() -> (ether|atm|whatever)_output() -> arpresolve()

Lookup is done in proper place (link-layer output routine) and it is possible
  to provide cached lle data.

For IPv6 situation is more complex:
  ip6_output() -> nd6_output() -> nd6_output_ifp() -> (whatever)_output() ->
    nd6_storelladdr()

We have ip6_ouput() which calls nd6_output() instead of link output routine.
nd6_output() does the following:
  * checks if lle exists, creates it if needed (similar to arpresolve())
  * performes lle state transitions (similar to arpresolve())
  * calls nd6_output_ifp() which pushes packets to link output routine along
    with running SeND/MAC hooks regardless of lle state
    (e.g. works as run-hooks placeholder).

After that, iface output routine like ether_output() calls nd6_storelladdr()
  which performs lle lookup once again.

As a result, we perform lookup twice for each outgoing packet for most types
  of interfaces. We also need to maintain runtime-checked table of 'nd6-free'
  interfaces (see nd6_need_cache()).

Fix this behavior by eliminating first ND lookup. To be more specific:
  * make all nd6_output() consumers use nd6_output_ifp() instead
  * rename nd6_output[_slow]() to nd6_resolve_[slow]()
  * convert nd6_resolve() and nd6_resolve_slow() to arpresolve() semantics,
    e.g. copy L2 address to buffer instead of pushing packet towards lower
    layers
  * Make all nd6_storelladdr() users use nd6_resolve()
  * eliminate nd6_storelladdr()

The resulting callchain is the following:
  ip6_output() -> nd6_output_ifp() -> (whatever)_output() -> nd6_resolve()

Error handling:
Currently sending packet to non-existing la results in ip6_<output|forward>
  -> nd6_output() -> nd6_output _lle() which returns 0.
In new scenario packet is propagated to <ether|whatever>_output() ->
  nd6_resolve() which will return EWOULDBLOCK, and that result
  will be converted to 0.

(And EWOULDBLOCK is actually used by IB/TOE code).

Sponsored by:		Yandex LLC
Differential Revision:	https://reviews.freebsd.org/D1469
2015-09-16 14:26:28 +00:00