NAME

SYNOPSIS

DESCRIPTION

LOOP DETECTION

A looped back link will be temporarily muted, i.e., all traffic received on that link is ignored.

IPFW PROCESSING

HOOKS

Instead of naming a hook linkX the hook might be also named uplinkX. The node does not learn MAC addresses on uplink hooks, which keeps the internal address table small. This way it is desirable to connect the lower hook of an ng_ether(4) node to an uplink hook of the bridge, and ignore the complexity of the outside world. Frames with unknown MACs are always sent out to uplink hooks, so no functionality is lost.

Frames with unknown destination MAC addresses are replicated to any available hook, unless the first connected hook is an uplink hook. In this case the node assumes, that all unknown MAC addresses are located soley on the uplink hooks and only those hooks will be used to send out frames with unknown destination MACs. If the first connected hook is an link hook, the node will replicate such frames to all types of hooks, even if uplink hooks are connected later.

CONTROL MESSAGES

NGM_BRIDGE_SET_CONFIG (setconfig)

Set the node configuration. This command takes a struct ng_bridge_config as an argument:

/* Node configuration structure */
struct ng_bridge_config {
  u_char      debugLevel;           /* debug level */
  uint32_t    loopTimeout;          /* link loopback mute time */
  uint32_t    maxStaleness;         /* max host age before nuking */
  uint32_t    minStableAge;         /* min time for a stable host */
};
    

The debugLevel field sets the debug level on the node. At level of 2 or greater, detected loops are logged. The default level is 1.

The loopTimeout determines how long (in seconds) a looped link is muted. The default is 60 seconds. The maxStaleness parameter determines how long a period of inactivity before a host's entry is forgotten. The default is 15 minutes. The minStableAge determines how quickly a host must jump from one link to another before we declare a loopback condition. The default is one second.

NGM_BRIDGE_GET_CONFIG (getconfig)

Returns the current configuration as a struct ng_bridge_config.

NGM_BRIDGE_RESET (reset)

Causes the node to forget all hosts and unmute all links. The node configuration is not changed.

NGM_BRIDGE_GET_STATS (getstats)

This command takes a four byte link number as an argument and returns a struct ng_bridge_link_stats containing statistics for the corresponding link, which must be currently connected:

/* Statistics structure (one for each link) */
struct ng_bridge_link_stats {
  uint64_t   recvOctets;     /* total octets rec'd on link */
  uint64_t   recvPackets;    /* total pkts rec'd on link */
  uint64_t   recvMulticasts; /* multicast pkts rec'd on link */
  uint64_t   recvBroadcasts; /* broadcast pkts rec'd on link */
  uint64_t   recvUnknown;    /* pkts rec'd with unknown dest addr */
  uint64_t   recvRunts;      /* pkts rec'd less than 14 bytes */
  uint64_t   recvInvalid;    /* pkts rec'd with bogus source addr */
  uint64_t   xmitOctets;     /* total octets xmit'd on link */
  uint64_t   xmitPackets;    /* total pkts xmit'd on link */
  uint64_t   xmitMulticasts; /* multicast pkts xmit'd on link */
  uint64_t   xmitBroadcasts; /* broadcast pkts xmit'd on link */
  uint64_t   loopDrops;      /* pkts dropped due to loopback */
  uint64_t   loopDetects;    /* number of loop detections */
  uint64_t   memoryFailures; /* times couldn't get mem or mbuf */
};
    

Negative numbers refer to the uplink hooks. So querying for -7 will get the statistics for hook uplink7.

NGM_BRIDGE_CLR_STATS (clrstats)

This command takes a four byte link number as an argument and clears the statistics for that link.

NGM_BRIDGE_GETCLR_STATS (getclrstats)

Same as NGM_BRIDGE_GET_STATS, but also atomically clears the statistics as well.

NGM_BRIDGE_GET_TABLE (gettable)

Returns the current host mapping table used to direct packets, in a struct ng_bridge_host_ary.

NGM_BRIDGE_SET_PERSISTENT (setpersistent)

This command sets the persistent flag on the node, and takes no arguments.

NGM_BRIDGE_MOVE_HOST (movehost)

This command takes a struct ng_bridge_move_host as an argument. It assigns the MAC addr to the hook. If the hook is the empty string, the incoming hook of the control message is used as fallback.

If necessary, the MAC is removed from the currently assigned hook and moved to the new one. If the MAC is moved faster than minStableAge, the hook is considered as a loop and will block traffic for loopTimeout seconds.

struct ng_bridge_move_host {
  u_char  addr[ETHER_ADDR_LEN];	/* ethernet address */
  char    hook[NG_HOOKSIZ];	/* link where addr can be found */
};
    

SHUTDOWN

FILES

/usr/share/examples/netgraph/ether.bridge

Example script showing how to set up a bridging network

SEE ALSO

HISTORY

AUTHORS