- Add RATELIMIT kernel configuration keyword which must be set to
enable the new functionality.
- Add support for hardware driven, Receive Side Scaling, RSS aware, rate
limited sendqueues and expose the functionality through the already
established SO_MAX_PACING_RATE setsockopt(). The API support rates in
the range from 1 to 4Gbytes/s which are suitable for regular TCP and
UDP streams. The setsockopt(2) manual page has been updated.
- Add rate limit function callback API to "struct ifnet" which supports
the following operations: if_snd_tag_alloc(), if_snd_tag_modify(),
if_snd_tag_query() and if_snd_tag_free().
- Add support to ifconfig to view, set and clear the IFCAP_TXRTLMT
flag, which tells if a network driver supports rate limiting or not.
- This patch also adds support for rate limiting through VLAN and LAGG
intermediate network devices.
- How rate limiting works:
1) The userspace application calls setsockopt() after accepting or
making a new connection to set the rate which is then stored in the
socket structure in the kernel. Later on when packets are transmitted
a check is made in the transmit path for rate changes. A rate change
implies a non-blocking ifp->if_snd_tag_alloc() call will be made to the
destination network interface, which then sets up a custom sendqueue
with the given rate limitation parameter. A "struct m_snd_tag" pointer is
returned which serves as a "snd_tag" hint in the m_pkthdr for the
subsequently transmitted mbufs.
2) When the network driver sees the "m->m_pkthdr.snd_tag" different
from NULL, it will move the packets into a designated rate limited sendqueue
given by the snd_tag pointer. It is up to the individual drivers how the rate
limited traffic will be rate limited.
3) Route changes are detected by the NIC drivers in the ifp->if_transmit()
routine when the ifnet pointer in the incoming snd_tag mismatches the
one of the network interface. The network adapter frees the mbuf and
returns EAGAIN which causes the ip_output() to release and clear the send
tag. Upon next ip_output() a new "snd_tag" will be tried allocated.
4) When the PCB is detached the custom sendqueue will be released by a
non-blocking ifp->if_snd_tag_free() call to the currently bound network
interface.
Reviewed by: wblock (manpages), adrian, gallatin, scottl (network)
Differential Revision: https://reviews.freebsd.org/D3687
Sponsored by: Mellanox Technologies
MFC after: 3 months
then drop lock, run the attach routines, and then set it to specific
proto. This removes tons of WITNESS warnings.
- Make lagg protocol attach handlers not failing and allocate memory
with M_WAITOK.
Sponsored by: Netflix
Sponsored by: Nginx, Inc.
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
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.
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.
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@
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.
