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No rights are granted, in any manner or form, to use Whistle 11.\" Communications, Inc. trademarks, including the mark "WHISTLE 12.\" COMMUNICATIONS" on advertising, endorsements, or otherwise except as 13.\" such appears in the above copyright notice or in the software. 14.\" 15.\" THIS SOFTWARE IS BEING PROVIDED BY WHISTLE COMMUNICATIONS "AS IS", AND 16.\" TO THE MAXIMUM EXTENT PERMITTED BY LAW, WHISTLE COMMUNICATIONS MAKES NO 17.\" REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED, REGARDING THIS SOFTWARE, 18.\" INCLUDING WITHOUT LIMITATION, ANY AND ALL IMPLIED WARRANTIES OF 19.\" MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT. 20.\" WHISTLE COMMUNICATIONS DOES NOT WARRANT, GUARANTEE, OR MAKE ANY 21.\" REPRESENTATIONS REGARDING THE USE OF, OR THE RESULTS OF THE USE OF THIS 22.\" SOFTWARE IN TERMS OF ITS CORRECTNESS, ACCURACY, RELIABILITY OR OTHERWISE. 23.\" IN NO EVENT SHALL WHISTLE COMMUNICATIONS BE LIABLE FOR ANY DAMAGES 24.\" RESULTING FROM OR ARISING OUT OF ANY USE OF THIS SOFTWARE, INCLUDING 25.\" WITHOUT LIMITATION, ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, 26.\" PUNITIVE, OR CONSEQUENTIAL DAMAGES, PROCUREMENT OF SUBSTITUTE GOODS OR 27.\" SERVICES, LOSS OF USE, DATA OR PROFITS, HOWEVER CAUSED AND UNDER ANY 28.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 29.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 30.\" THIS SOFTWARE, EVEN IF WHISTLE COMMUNICATIONS IS ADVISED OF THE POSSIBILITY 31.\" OF SUCH DAMAGE. 32.\" 33.\" Author: Archie Cobbs <archie@FreeBSD.org> 34.\" 35.\" $FreeBSD$ 36.\" 37.Dd October 2, 2019 38.Dt NG_BRIDGE 4 39.Os 40.Sh NAME 41.Nm ng_bridge 42.Nd Ethernet bridging netgraph node type 43.Sh SYNOPSIS 44.In sys/types.h 45.In netgraph/ng_bridge.h 46.Sh DESCRIPTION 47The 48.Nm bridge 49node type performs Ethernet bridging over one or more links. 50Each link (represented by a connected hook) is used to transmit 51and receive raw Ethernet frames. 52As packets are received, the node learns which link each 53host resides on. 54Packets unicast to a known host are directed out the appropriate 55link only, and other links are spared the traffic. 56This behavior is in contrast to a hub, which always forwards 57every received packet to every other link. 58.Sh LOOP DETECTION 59The 60.Nm bridge 61node incorporates a simple loop detection algorithm. 62A loop is when two ports are connected to the same physical medium. 63Loops are important to avoid because of packet storms, which severely 64degrade performance. 65A packet storm results when the same packet is sent and received 66over and over again. 67If a host is detected on link A, and is then detected on link B 68within a certain time period after first being detected on link A, 69then link B is considered to be a looped back link. 70The time period is called the minimum stable time. 71.Pp 72A looped back link will be temporarily muted, i.e., all traffic 73received on that link is ignored. 74.Sh IPFW PROCESSING 75Processing of IP packets via the 76.Xr ipfirewall 4 77mechanism on a per-link basis is not yet implemented. 78.Sh HOOKS 79This node type supports an unlimited number of hooks. 80Each connected hook represents a bridged link. 81The hooks are named 82.Dv link0 , 83.Dv link1 , 84etc. 85Typically these hooks are connected to the 86.Dv lower 87hooks of one or more 88.Xr ng_ether 4 89nodes. 90To connect the host machine to a bridged network, simply connect the 91.Dv upper 92hook of an 93.Xr ng_ether 4 94node to the bridge node. 95.Sh CONTROL MESSAGES 96This node type supports the generic control messages, plus the 97following: 98.Bl -tag -width foo 99.It Dv NGM_BRIDGE_SET_CONFIG Pq Ic setconfig 100Set the node configuration. 101This command takes a 102.Dv "struct ng_bridge_config" 103as an argument: 104.Bd -literal -offset 0n 105/* Node configuration structure */ 106struct ng_bridge_config { 107 u_char debugLevel; /* debug level */ 108 uint32_t loopTimeout; /* link loopback mute time */ 109 uint32_t maxStaleness; /* max host age before nuking */ 110 uint32_t minStableAge; /* min time for a stable host */ 111}; 112.Ed 113.Pp 114The 115.Dv debugLevel 116field sets the debug level on the node. 117At level of 2 or greater, detected loops are logged. 118The default level is 1. 119.Pp 120The 121.Dv loopTimeout 122determines how long (in seconds) a looped link is muted. 123The default is 60 seconds. 124The 125.Dv maxStaleness 126parameter determines how long a period of inactivity before 127a host's entry is forgotten. 128The default is 15 minutes. 129The 130.Dv minStableAge 131determines how quickly a host must jump from one link to another 132before we declare a loopback condition. 133The default is one second. 134.It Dv NGM_BRIDGE_GET_CONFIG Pq Ic getconfig 135Returns the current configuration as a 136.Dv "struct ng_bridge_config" . 137.It Dv NGM_BRIDGE_RESET Pq Ic reset 138Causes the node to forget all hosts and unmute all links. 139The node configuration is not changed. 140.It Dv NGM_BRIDGE_GET_STATS Pq Ic getstats 141This command takes a four byte link number as an argument and 142returns a 143.Dv "struct ng_bridge_link_stats" 144containing statistics for the corresponding link, which must be 145currently connected: 146.Bd -literal -offset 0n 147/* Statistics structure (one for each link) */ 148struct ng_bridge_link_stats { 149 uint64_t recvOctets; /* total octets rec'd on link */ 150 uint64_t recvPackets; /* total pkts rec'd on link */ 151 uint64_t recvMulticasts; /* multicast pkts rec'd on link */ 152 uint64_t recvBroadcasts; /* broadcast pkts rec'd on link */ 153 uint64_t recvUnknown; /* pkts rec'd with unknown dest addr */ 154 uint64_t recvRunts; /* pkts rec'd less than 14 bytes */ 155 uint64_t recvInvalid; /* pkts rec'd with bogus source addr */ 156 uint64_t xmitOctets; /* total octets xmit'd on link */ 157 uint64_t xmitPackets; /* total pkts xmit'd on link */ 158 uint64_t xmitMulticasts; /* multicast pkts xmit'd on link */ 159 uint64_t xmitBroadcasts; /* broadcast pkts xmit'd on link */ 160 uint64_t loopDrops; /* pkts dropped due to loopback */ 161 uint64_t loopDetects; /* number of loop detections */ 162 uint64_t memoryFailures; /* times couldn't get mem or mbuf */ 163}; 164.Ed 165.It Dv NGM_BRIDGE_CLR_STATS Pq Ic clrstats 166This command takes a four byte link number as an argument and 167clears the statistics for that link. 168.It Dv NGM_BRIDGE_GETCLR_STATS Pq Ic getclrstats 169Same as 170.Dv NGM_BRIDGE_GET_STATS , 171but also atomically clears the statistics as well. 172.It Dv NGM_BRIDGE_GET_TABLE Pq Ic gettable 173Returns the current host mapping table used to direct packets, in a 174.Dv "struct ng_bridge_host_ary" . 175.It Dv NGM_BRIDGE_SET_PERSISTENT Pq Ic setpersistent 176This command sets the persistent flag on the node, and takes no arguments. 177.El 178.Sh SHUTDOWN 179This node shuts down upon receipt of a 180.Dv NGM_SHUTDOWN 181control message, or when all hooks have been disconnected. 182Setting the persistent flag via a 183.Dv NGM_BRIDGE_SET_PERSISTENT 184control message disables automatic node shutdown when the last hook gets 185disconnected. 186.Sh FILES 187.Bl -tag -width XXXXXXXX -compact 188.It Pa /usr/share/examples/netgraph/ether.bridge 189Example script showing how to set up a bridging network 190.El 191.Sh SEE ALSO 192.Xr if_bridge 4 , 193.Xr netgraph 4 , 194.Xr ng_ether 4 , 195.Xr ng_hub 4 , 196.Xr ng_one2many 4 , 197.Xr ngctl 8 198.Sh HISTORY 199The 200.Nm 201node type was implemented in 202.Fx 4.2 . 203.Sh AUTHORS 204.An Archie Cobbs Aq Mt archie@FreeBSD.org 205