- Copy stable/10 (r259064) to releng/10.0 as part of the
10.0-RELEASE cycle.
- Update __FreeBSD_version [1]
- Set branch name to -RC1

[1] 10.0-CURRENT __FreeBSD_version value ended at '55', so
start releng/10.0 at '100' so the branch is started with
a value ending in zero.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Break out the static, global LACP debug options into a per-lagg unit
sysctl tree.

* Create a net.link.lagg.X.lacp node
* Add a debug node under that for tx_test and rx_test
* Add lacp_strict_mode, defaulting to 1

tx_test and rx_test are still a bitmap of unit numbers for now.
At some point it would be nice to create child nodes of the lagg bundle
for each sub-interface, and then populate those with various knobs
and statistics.

Sponsored by: Netflix

Remove extra semicolons.

Pointed out by: antoine

Switch the LACP state machine over to its own mutex to protect the internals,
this means that it no longer grabs the lagg rwlock. Use two port table arrays
which list the active ports for Tx and switch between them with an atomic op.
Now the lagg rwlock is only exclusively locked for management (ioctls) and
queuing of lacp control frames isnt needed.

Pass any unmatched slowprotocols frames up the stack instead of dropping them,
there are more subtypes than just LACP.

Allow the LACP state to be queried from userland which at the moment is the
actor and partner peer info. Print out the active aggregator and per port data
in verbose mode from ifconfig.

Approved by: re (mux)

non-functional cleanup
- remove dead code
- use consistent variable names
- gc unused defines
- whitespace cleanup

Compare the partner system priority when choosing the aggregator.

Implement the Marker Protocol. A marker frame is placed on the interface queue
of each port and any further packets are blocked, when the all the marker frames
have been returned to us from the remote network device then we can be sure
that all interface queues are empty.

This is needed when a port is added or removed from the aggregation since it
will affect the hash based distribution, if the queues are not empty then a
packet from an existing connection may be placed on a different interface and
arrive out of order. This was previously achieved by suppressing transmission for
1 second, now that there is an active feedback this timeout as been increased
to 3 seconds and used as a fallback.

Change from a mutex to a read/write lock. This allows the tx port to be
selected simultaneously by multiple senders and transmit/receive is not
serialised between aggregated interfaces.

Change from using if_delmulti() to if_delmulti_ifma() as it simplifies the code
and is safe to use if the ifp has disappeared.

Suggested by: bms

Rename the trunk(4) driver to lagg(4) as it is too similar to vlan trunking.

The name trunk is misused as the networking term trunk means carrying multiple
VLANs over a single connection. The IEEE standard for link aggregation (802.3
section 3) does not talk about 'trunk' at all while it is used throughout IEEE
802.1Q in describing vlans.

The lagg(4) driver provides link aggregation, failover and fault tolerance.

Discussed on: current@

Add the trunk(4) driver for providing link aggregation, failover and fault
tolerance. This driver allows aggregation of multiple network interfaces as
one virtual interface using a number of different protocols/algorithms.

failover - Sends traffic through the secondary port if the master becomes
inactive.
fec - Supports Cisco Fast EtherChannel.
lacp - Supports the IEEE 802.3ad Link Aggregation Control Protocol
(LACP) and the Marker Protocol.
loadbalance - Static loadbalancing using an outgoing hash.
roundrobin - Distributes outgoing traffic using a round-robin scheduler
through all active ports.

This code was obtained from OpenBSD and this also includes 802.3ad LACP support
from agr(4) in NetBSD.