bridge: Fix a NULL dereference

[mirror_ovs.git] / vswitchd / ovs-vswitchd.8.in

.\" -*- nroff -*-
.de IQ
.  br
.  ns
.  IP "\\$1"
..
.TH ovs\-vswitchd 8 "@VERSION@" "Open vSwitch" "Open vSwitch Manual"
.\" This program's name:
.ds PN ovs\-vswitchd
.
.SH NAME
ovs\-vswitchd \- Open vSwitch daemon
.
.SH SYNOPSIS
\fBovs\-vswitchd \fR[\fIdatabase\fR]
.
.SH DESCRIPTION
A daemon that manages and controls any number of Open vSwitch switches
on the local machine.
.PP
The \fIdatabase\fR argument specifies how \fBovs\-vswitchd\fR connects
to \fBovsdb\-server\fR.  The default is \fBunix:@RUNDIR@/db.sock\fR.
The following forms are accepted:
.so ovsdb/remote-active.man
.so ovsdb/remote-passive.man
.PP
\fBovs\-vswitchd\fR retrieves its configuration from \fIdatabase\fR at
startup.  It sets up Open vSwitch datapaths and then operates
switching across each bridge described in its configuration files.  As
the database changes, \fBovs\-vswitchd\fR automatically updates its
configuration to match.
.PP
\fBovs\-vswitchd\fR switches may be configured with any of the following
features:
.
.IP \(bu
L2 switching with MAC learning.
.
.IP \(bu
NIC bonding with automatic fail-over and source MAC-based TX load
balancing ("SLB").
.
.IP \(bu
802.1Q VLAN support.
.
.IP \(bu
Port mirroring, with optional VLAN tagging.
.
.IP \(bu
NetFlow v5 flow logging.
.
.IP \(bu
sFlow(R) monitoring.
.
.IP \(bu
Connectivity to an external OpenFlow controller, such as NOX.
.
.PP
Only a single instance of \fBovs\-vswitchd\fR is intended to run at a time.
A single \fBovs\-vswitchd\fR can manage any number of switch instances, up
to the maximum number of supported Open vSwitch datapaths.
.PP
\fBovs\-vswitchd\fR does all the necessary management of Open vSwitch datapaths
itself.  Thus, external tools, such \fBovs\-dpctl\fR(8), are not needed for
managing datapaths in conjunction with \fBovs\-vswitchd\fR, and their use
to modify datapaths when \fBovs\-vswitchd\fR is running can interfere with
its operation.  (\fBovs\-dpctl\fR may still be useful for diagnostics.)
.PP
An Open vSwitch datapath kernel module must be loaded for \fBovs\-vswitchd\fR
to be useful.  Please refer to the \fBINSTALL.Linux\fR file included in the
Open vSwitch distribution for instructions on how to build and load
the Open vSwitch kernel module.
.PP
.SH OPTIONS
.IP "\fB\-\-mlockall\fR"
Causes \fBovs\-vswitchd\fR to call the \fBmlockall()\fR function, to
attempt to lock all of its process memory into physical RAM,
preventing the kernel from paging any of its memory to disk.  This
helps to avoid networking interruptions due to system memory pressure.
.IP
Some systems do not support \fBmlockall()\fR at all, and other systems
only allow privileged users, such as the superuser, to use it.
\fBovs\-vswitchd\fR emits a log message if \fBmlockall()\fR is
unavailable or unsuccessful.
.
.IP "\fB\-\-enable\-of14\fR"
Specifying this option allows OpenFlow 1.4 to be used if it is enabled
through the \fBprotocols\fR column in the \fBController\fR.  Without
this option, \fBovs\-vswitchd\fR will not use OpenFlow 1.4 even if it
is enabled that way.  This option is present because OpenFlow 1.4
support is not safe: the daemon will abort when certain unimplemented
features are tested.  Thus, for now it is suitable only for
experimental use.  When the support is implemented safely, this option
will be removed.
.
.SS "Daemon Options"
.ds DD \
\fBovs\-vswitchd\fR detaches only after it has connected to the \
database, retrieved the initial configuration, and set up that \
configuration.
.so lib/daemon.man
.SS "Service Options"
.so lib/service.man
.SS "Public Key Infrastructure Options"
.so lib/ssl.man
.so lib/ssl-bootstrap.man
.so lib/vlog.man
.so lib/common.man
.
.SH "RUNTIME MANAGEMENT COMMANDS"
\fBovs\-appctl\fR(8) can send commands to a running
\fBovs\-vswitchd\fR process.  The currently supported commands are
described below.  The command descriptions assume an understanding of
how to configure Open vSwitch.
.SS "GENERAL COMMANDS"
.IP "\fBexit\fR"
Causes \fBovs\-vswitchd\fR to gracefully terminate.
.IP "\fBqos/show\fR \fIinterface\fR"
Queries the kernel for Quality of Service configuration and statistics
associated with the given \fIinterface\fR.
.IP "\fBbfd/show\fR [\fIinterface\fR]"
Displays detailed information about Bidirectional Forwarding Detection
configured on \fIinterface\fR.  If \fIinterface\fR is not specified,
then displays detailed information about all interfaces with BFD
enabled.
.IP "\fBbfd/set-forwarding\fR [\fIinterface\fR] \fIstatus\fR"
Force the fault status of the BFD module on \fIinterface\fR (or all
interfaces if none is given) to be \fIstatus\fR.  \fIstatus\fR can be
"true", "false", or "normal" which reverts to the standard behavior.
.IP "\fBcfm/show\fR [\fIinterface\fR]"
Displays detailed information about Connectivity Fault Management
configured on \fIinterface\fR.  If \fIinterface\fR is not specified,
then displays detailed information about all interfaces with CFM
enabled.
.IP "\fBcfm/set-fault\fR [\fIinterface\fR] \fIstatus\fR"
Force the fault status of the CFM module on \fIinterface\fR (or all
interfaces if none is given) to be \fIstatus\fR.  \fIstatus\fR can be
"true", "false", or "normal" which reverts to the standard behavior.
.IP "\fBstp/tcn\fR [\fIbridge\fR]"
Forces a topology change event on \fIbridge\fR if it's running STP.  This
may cause it to send Topology Change Notifications to its peers and flush
its MAC table..  If no \fIbridge\fR is given, forces a topology change
event on all bridges.
.SS "BRIDGE COMMANDS"
These commands manage bridges.
.IP "\fBfdb/flush\fR [\fIbridge\fR]"
Flushes \fIbridge\fR MAC address learning table, or all learning tables
if no \fIbridge\fR is given.
.IP "\fBfdb/show\fR \fIbridge\fR"
Lists each MAC address/VLAN pair learned by the specified \fIbridge\fR,
along with the port on which it was learned and the age of the entry,
in seconds.
.IP "\fBbridge/reconnect\fR [\fIbridge\fR]"
Makes \fIbridge\fR drop all of its OpenFlow controller connections and
reconnect.  If \fIbridge\fR is not specified, then all bridges drop
their controller connections and reconnect.
.IP
This command might be useful for debugging OpenFlow controller issues.
.
.IP "\fBbridge/dump\-flows\fR \fIbridge\fR"
Lists all flows in \fIbridge\fR, including those normally hidden to
commands such as \fBovs\-ofctl dump\-flows\fR.  Flows set up by mechanisms
such as in-band control and fail-open are hidden from the controller
since it is not allowed to modify or override them.
.SS "BOND COMMANDS"
These commands manage bonded ports on an Open vSwitch's bridges.  To
understand some of these commands, it is important to understand a
detail of the bonding implementation called ``source load balancing''
(SLB).  Instead of directly assigning Ethernet source addresses to
slaves, the bonding implementation computes a function that maps an
48-bit Ethernet source addresses into an 8-bit value (a ``MAC hash''
value).  All of the Ethernet addresses that map to a single 8-bit
value are then assigned to a single slave.
.IP "\fBbond/list\fR"
Lists all of the bonds, and their slaves, on each bridge.
.
.IP "\fBbond/show\fR [\fIport\fR]"
Lists all of the bond-specific information (updelay, downdelay, time
until the next rebalance) about the given bonded \fIport\fR, or all
bonded ports if no \fIport\fR is given.  Also lists information about
each slave: whether it is enabled or disabled, the time to completion
of an updelay or downdelay if one is in progress, whether it is the
active slave, the hashes assigned to the slave.  Any LACP information
related to this bond may be found using the \fBlacp/show\fR command.
.
.IP "\fBbond/migrate\fR \fIport\fR \fIhash\fR \fIslave\fR"
Only valid for SLB bonds.  Assigns a given MAC hash to a new slave.
\fIport\fR specifies the bond port, \fIhash\fR the MAC hash to be
migrated (as a decimal number between 0 and 255), and \fIslave\fR the
new slave to be assigned.
.IP
The reassignment is not permanent: rebalancing or fail-over will
cause the MAC hash to be shifted to a new slave in the usual
manner.
.IP
A MAC hash cannot be migrated to a disabled slave.
.IP "\fBbond/set\-active\-slave\fR \fIport\fR \fIslave\fR"
Sets \fIslave\fR as the active slave on \fIport\fR.  \fIslave\fR must
currently be enabled.
.IP
The setting is not permanent: a new active slave will be selected
if \fIslave\fR becomes disabled.
.IP "\fBbond/enable\-slave\fR \fIport\fR \fIslave\fR"
.IQ "\fBbond/disable\-slave\fR \fIport\fR \fIslave\fR"
Enables (or disables) \fIslave\fR on the given bond \fIport\fR, skipping any
updelay (or downdelay).
.IP
This setting is not permanent: it persists only until the carrier
status of \fIslave\fR changes.
.IP "\fBbond/hash\fR \fImac\fR [\fIvlan\fR] [\fIbasis\fR]"
Returns the hash value which would be used for \fImac\fR with \fIvlan\fR
and \fIbasis\fR if specified.
.
.IP "\fBlacp/show\fR [\fIport\fR]"
Lists all of the LACP related information about the given \fIport\fR:
active or passive, aggregation key, system id, and system priority.  Also
lists information about each slave: whether it is enabled or disabled,
whether it is attached or detached, port id and priority, actor
information, and partner information.  If \fIport\fR is not specified,
then displays detailed information about all interfaces with CFM
enabled.
.
.so ofproto/ofproto-dpif-unixctl.man
.so ofproto/ofproto-unixctl.man
.so lib/vlog-unixctl.man
.so lib/memory-unixctl.man
.so lib/coverage-unixctl.man
.
.SH "OPENFLOW IMPLEMENTATION"
.
.PP
This section documents aspects of OpenFlow for which the OpenFlow
specification requires documentation.
.
.SS "Packet buffering."
The OpenFlow specification, version 1.2, says:
.
.IP
Switches that implement buffering are expected to expose, through
documentation, both the amount of available buffering, and the length
of time before buffers may be reused.
.
.PP
Open vSwitch maintains a separate set of 256 packet buffers for each
OpenFlow connection.  Any given packet buffer is preserved until it is
referenced by an \fBOFPT_FLOW_MOD\fR or \fBOFPT_PACKET_OUT\fR request
or for 5 seconds, whichever comes first.
.
.SH "LIMITS"
.
.PP
We believe these limits to be accurate as of this writing.  These
limits assume the use of the Linux kernel datapath.
.
.IP \(bu
\fBovs\-vswitchd\fR started through \fBovs\-ctl\fR(8) provides a limit of 7500
file descriptors.  The limits on the number of bridges and ports is decided by
the availability of file descriptors.  With the Linux kernel datapath, creation
of a single bridge consumes 3 file descriptors and adding a port consumes
1 file descriptor.  Performance will degrade beyond 1,024 ports per bridge due
to fixed hash table sizing.  Other platforms may have different limitations.
.
.IP \(bu
2,048 MAC learning entries per bridge, by default.  (This is
configurable via \fBother\-config:mac\-table\-size\fR in the
\fBBridge\fR table.  See \fBovs\-vswitchd.conf.db\fR(5) for details.)
.
.IP \(bu
Kernel flows are limited only by memory available to the kernel.
Performance will degrade beyond 1,048,576 kernel flows per bridge with
a 32-bit kernel, beyond 262,144 with a 64-bit kernel.
(\fBovs\-vswitchd\fR should never install anywhere near that many
flows.)
.
.IP \(bu
OpenFlow flows are limited only by available memory.  Performance is
linear in the number of unique wildcard patterns.  That is, an
OpenFlow table that contains many flows that all match on the same
fields in the same way has a constant-time lookup, but a table that
contains many flows that match on different fields requires lookup
time linear in the number of flows.
.
.IP \(bu
255 ports per bridge participating in 802.1D Spanning Tree Protocol.
.
.IP \(bu
32 mirrors per bridge.
.
.IP \(bu
15 bytes for the name of a port.  (This is a Linux kernel limitation.)
.
.SH "SEE ALSO"
.BR ovs\-appctl (8),
.BR ovsdb\-server (1),
\fBINSTALL.Linux\fR in the Open vSwitch distribution.