206 lines
7.3 KiB
Groff
206 lines
7.3 KiB
Groff
.\" Copyright (c) 2000 Whistle Communications, Inc.
|
|
.\" All rights reserved.
|
|
.\"
|
|
.\" Subject to the following obligations and disclaimer of warranty, use and
|
|
.\" redistribution of this software, in source or object code forms, with or
|
|
.\" without modifications are expressly permitted by Whistle Communications;
|
|
.\" provided, however, that:
|
|
.\" 1. Any and all reproductions of the source or object code must include the
|
|
.\" copyright notice above and the following disclaimer of warranties; and
|
|
.\" 2. No rights are granted, in any manner or form, to use Whistle
|
|
.\" Communications, Inc. trademarks, including the mark "WHISTLE
|
|
.\" COMMUNICATIONS" on advertising, endorsements, or otherwise except as
|
|
.\" such appears in the above copyright notice or in the software.
|
|
.\"
|
|
.\" THIS SOFTWARE IS BEING PROVIDED BY WHISTLE COMMUNICATIONS "AS IS", AND
|
|
.\" TO THE MAXIMUM EXTENT PERMITTED BY LAW, WHISTLE COMMUNICATIONS MAKES NO
|
|
.\" REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED, REGARDING THIS SOFTWARE,
|
|
.\" INCLUDING WITHOUT LIMITATION, ANY AND ALL IMPLIED WARRANTIES OF
|
|
.\" MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT.
|
|
.\" WHISTLE COMMUNICATIONS DOES NOT WARRANT, GUARANTEE, OR MAKE ANY
|
|
.\" REPRESENTATIONS REGARDING THE USE OF, OR THE RESULTS OF THE USE OF THIS
|
|
.\" SOFTWARE IN TERMS OF ITS CORRECTNESS, ACCURACY, RELIABILITY OR OTHERWISE.
|
|
.\" IN NO EVENT SHALL WHISTLE COMMUNICATIONS BE LIABLE FOR ANY DAMAGES
|
|
.\" RESULTING FROM OR ARISING OUT OF ANY USE OF THIS SOFTWARE, INCLUDING
|
|
.\" WITHOUT LIMITATION, ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
|
|
.\" PUNITIVE, OR CONSEQUENTIAL DAMAGES, PROCUREMENT OF SUBSTITUTE GOODS OR
|
|
.\" SERVICES, LOSS OF USE, DATA OR PROFITS, HOWEVER CAUSED AND UNDER ANY
|
|
.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
|
|
.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
|
|
.\" THIS SOFTWARE, EVEN IF WHISTLE COMMUNICATIONS IS ADVISED OF THE POSSIBILITY
|
|
.\" OF SUCH DAMAGE.
|
|
.\"
|
|
.\" Author: Archie Cobbs <archie@FreeBSD.org>
|
|
.\"
|
|
.\" $FreeBSD$
|
|
.\"
|
|
.Dd August 31, 2000
|
|
.Dt NG_BRIDGE 4
|
|
.Os
|
|
.Sh NAME
|
|
.Nm ng_bridge
|
|
.Nd Ethernet bridging netgraph node type
|
|
.Sh SYNOPSIS
|
|
.In sys/types.h
|
|
.In netgraph/ng_bridge.h
|
|
.Sh DESCRIPTION
|
|
The
|
|
.Nm bridge
|
|
node type performs Ethernet bridging over one or more links.
|
|
Each link (represented by a connected hook) is used to transmit
|
|
and receive raw Ethernet frames.
|
|
As packets are received, the node learns which link each
|
|
host resides on.
|
|
Packets unicast to a known host are directed out the appropriate
|
|
link only, and other links are spared the traffic.
|
|
This behavior is in contrast to a hub, which always forwards
|
|
every received packet to every other link.
|
|
.Sh LOOP DETECTION
|
|
The
|
|
.Nm bridge
|
|
node incorporates a simple loop detection algorithm.
|
|
A loop is when two ports are connected to the same physical medium.
|
|
Loops are important to avoid because of packet storms, which severely
|
|
degrade performance.
|
|
A packet storm results when the same packet is sent and received
|
|
over and over again.
|
|
If a host is detected on link A, and is then detected on link B
|
|
within a certain time period after first being detected on link A,
|
|
then link B is considered to be a looped back link.
|
|
The time period is called the minimum stable time.
|
|
.Pp
|
|
A looped back link will be temporarily muted, i.e., all traffic
|
|
received on that link is ignored.
|
|
.Sh IPFW PROCESSING
|
|
Processing of IP packets via the
|
|
.Xr ipfirewall 4
|
|
mechanism on a per-link basis is not yet implemented.
|
|
.Sh HOOKS
|
|
This node type supports up to
|
|
.Dv NG_BRIDGE_MAX_LINKS
|
|
hooks.
|
|
Each connected hook represents a bridged link.
|
|
The hooks are named
|
|
.Dv link0 ,
|
|
.Dv link1 ,
|
|
etc.
|
|
Typically these hooks are connected to the
|
|
.Dv lower
|
|
hooks of one or more
|
|
.Xr ng_ether 4
|
|
nodes.
|
|
To connect the host machine to a bridged network, simply connect the
|
|
.Dv upper
|
|
hook of an
|
|
.Xr ng_ether 4
|
|
node to the bridge node.
|
|
.Sh CONTROL MESSAGES
|
|
This node type supports the generic control messages, plus the
|
|
following:
|
|
.Bl -tag -width foo
|
|
.It Dv NGM_BRIDGE_SET_CONFIG
|
|
Set the node configuration.
|
|
This command takes a
|
|
.Dv "struct ng_bridge_config"
|
|
as an argument:
|
|
.Bd -literal -offset 0n
|
|
/* Node configuration structure */
|
|
struct ng_bridge_config {
|
|
u_char ipfw[NG_BRIDGE_MAX_LINKS]; /* enable ipfw */
|
|
u_char debugLevel; /* debug level */
|
|
u_int32_t loopTimeout; /* link loopback mute time */
|
|
u_int32_t maxStaleness; /* max host age before nuking */
|
|
u_int32_t minStableAge; /* min time for a stable host */
|
|
};
|
|
.Ed
|
|
.Pp
|
|
The
|
|
.Dv ipfw
|
|
array enables
|
|
.Xr ipfirewall 4
|
|
processing of IP packets received on the corresponding links.
|
|
The
|
|
.Dv debugLevel
|
|
field sets the debug level on the node.
|
|
At level of 2 or greater, detected loops are logged.
|
|
The default level is 1.
|
|
.Pp
|
|
The
|
|
.Dv loopTimeout
|
|
determines how long (in seconds) a looped link is muted.
|
|
The default is 60 seconds.
|
|
The
|
|
.Dv maxStaleness
|
|
parameter determines how long a period of inactivity before
|
|
a host's entry is forgotten.
|
|
The default is 15 minutes.
|
|
The
|
|
.Dv minStableAge
|
|
determines how quickly a host must jump from one link to another
|
|
before we declare a loopback condition.
|
|
The default is one second.
|
|
.Pp
|
|
.It Dv NGM_BRIDGE_GET_CONFIG
|
|
Returns the current configuration as a
|
|
.Dv "struct ng_bridge_config" .
|
|
.It Dv NGM_BRIDGE_RESET
|
|
Causes the node to forget all hosts and unmute all links.
|
|
The node configuration is not changed.
|
|
.It Dv NGM_BRIDGE_GET_STATS
|
|
This command takes a four byte link number as an argument and
|
|
returns a
|
|
.Dv "struct ng_bridge_link_stats"
|
|
containing statistics for the corresponding link, which must be
|
|
currently connected:
|
|
.Bd -literal -offset 0n
|
|
/* Statistics structure (one for each link) */
|
|
struct ng_bridge_link_stats {
|
|
u_int64_t recvOctets; /* total octets rec'd on link */
|
|
u_int64_t recvPackets; /* total pkts rec'd on link */
|
|
u_int64_t recvMulticasts; /* multicast pkts rec'd on link */
|
|
u_int64_t recvBroadcasts; /* broadcast pkts rec'd on link */
|
|
u_int64_t recvUnknown; /* pkts rec'd with unknown dest addr */
|
|
u_int64_t recvRunts; /* pkts rec'd less than 14 bytes */
|
|
u_int64_t recvInvalid; /* pkts rec'd with bogus source addr */
|
|
u_int64_t xmitOctets; /* total octets xmit'd on link */
|
|
u_int64_t xmitPackets; /* total pkts xmit'd on link */
|
|
u_int64_t xmitMulticasts; /* multicast pkts xmit'd on link */
|
|
u_int64_t xmitBroadcasts; /* broadcast pkts xmit'd on link */
|
|
u_int64_t loopDrops; /* pkts dropped due to loopback */
|
|
u_int64_t loopDetects; /* number of loop detections */
|
|
u_int64_t memoryFailures; /* times couldn't get mem or mbuf */
|
|
};
|
|
.Ed
|
|
.It Dv NGM_BRIDGE_CLR_STATS
|
|
This command takes a four byte link number as an argument and
|
|
clears the statistics for that link.
|
|
.It Dv NGM_BRIDGE_GETCLR_STATS
|
|
Same as
|
|
.Dv NGM_BRIDGE_GET_STATS ,
|
|
but also atomically clears the statistics as well.
|
|
.It Dv NGM_BRIDGE_GET_TABLE
|
|
Returns the current host mapping table used to direct packets, in a
|
|
.Dv "struct ng_bridge_host_ary" .
|
|
.El
|
|
.Sh SHUTDOWN
|
|
This node shuts down upon receipt of a
|
|
.Dv NGM_SHUTDOWN
|
|
control message, or when all hooks have been disconnected.
|
|
.Sh FILES
|
|
.Bl -tag -width XXXXXXXX -compact
|
|
.It Pa /usr/share/examples/netgraph/ether.bridge
|
|
Example script showing how to set up a bridging network
|
|
.El
|
|
.Sh SEE ALSO
|
|
.Xr bridge 4 ,
|
|
.Xr netgraph 4 ,
|
|
.Xr ng_ether 4 ,
|
|
.Xr ngctl 8
|
|
.Sh HISTORY
|
|
The
|
|
.Nm
|
|
node type was implemented in
|
|
.Fx 4.2 .
|
|
.Sh AUTHORS
|
|
.An Archie Cobbs Aq archie@FreeBSD.org
|