xref: /freebsd/share/man/man4/ng_one2many.4 (revision 2008043f386721d58158e37e0d7e50df8095942d)
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33.\" Author: Archie Cobbs <archie@FreeBSD.org>
34.\"
35.Dd November 13, 2012
36.Dt NG_ONE2MANY 4
37.Os
38.Sh NAME
39.Nm ng_one2many
40.Nd packet multiplexing netgraph node type
41.Sh SYNOPSIS
42.In sys/types.h
43.In netgraph/ng_one2many.h
44.Sh DESCRIPTION
45The
46.Nm one2many
47provides a simple mechanism for routing packets over several links
48in a one-to-many (and in the reverse direction, many-to-one) fashion.
49There is a single hook named
50.Dv one ,
51and multiple hooks named
52.Dv many0 ,
53.Dv many1 ,
54etc.
55Packets received on any of the
56.Dv many
57hooks are forwarded out the
58.Dv one
59hook.
60Packets received on the
61.Dv one
62hook are forwarded out one or more of the
63.Dv many
64hooks; which hook(s) is determined by the node's configured
65transmit algorithm.
66Packets are not altered in any way.
67.Pp
68Each of the connected many links may be considered to be up or down.
69Packets are never delivered out a many hook that is down.
70How a link is determined to be up or down depends on the node's
71configured link failure detection algorithm.
72.Pp
73Before an interface or link can be plumbed into a group, its status
74must be marked as being
75.Dq up .
76This is normally setup during the initial boot stages by
77.Xr rc.conf 5 .
78It is also possible to change an interface's status to
79.Dq up
80by using the
81.Xr ifconfig 8
82utility.
83.Sh TRANSMIT ALGORITHMS
84.Bl -tag -width foo
85.It Dv NG_ONE2MANY_XMIT_ROUNDROBIN
86Packets are delivered out the many hooks in sequential order.
87Each packet goes out on a different
88.Dv many
89hook.
90.It Dv NG_ONE2MANY_XMIT_ALL
91Packets are delivered out all the
92.Dv many
93hooks.
94Each packet goes out each
95.Dv many
96hook.
97.It Dv NG_ONE2MANY_XMIT_FAILOVER
98Packets are delivered out the first active
99.Dv many
100hook.
101.El
102.Pp
103In the future other algorithms may be added as well.
104.Sh LINK FAILURE DETECTION
105The node distinguishes between active and failed links.
106Data is sent only to active links.
107The following link failure detection algorithms are available:
108.Bl -tag -width foo
109.It Dv NG_ONE2MANY_FAIL_MANUAL
110The node is explicitly told which of the links are up via the
111.Dv NGM_ONE2MANY_SET_CONFIG
112control message (see below).
113Newly connected links are down until configured otherwise.
114.It Dv NG_ONE2MANY_FAIL_NOTIFY
115The node listens to flow control message from
116.Va many
117hooks, and considers link failed if
118.Dv NGM_LINK_IS_DOWN
119is received.
120If the
121.Dv NGM_LINK_IS_UP
122message is received, node considers link active.
123.El
124.Pp
125In the future other algorithms may be added as well.
126.Pp
127When all links are considered failed, node sends the
128.Dv NGM_LINK_IS_DOWN
129message towards the
130.Va one
131hook.
132When at least one link comes up, node sends the
133.Dv NGM_LINK_IS_UP
134message towards the
135.Va one
136hook.
137.Sh HOOKS
138This node type supports up to
139.Dv NG_ONE2MANY_MAX_LINKS
140hooks named
141.Dv many0 ,
142.Dv many1 ,
143etc.,
144plus a single hook named
145.Dv one .
146.Sh CONTROL MESSAGES
147This node type supports the generic control messages, plus the
148following:
149.Bl -tag -width foo
150.It Dv NGM_ONE2MANY_SET_CONFIG Pq Ic setconfig
151Sets the node configuration using a
152.Dv "struct ng_one2many_link_config"
153as the control message argument:
154.Bd -literal
155/* Node configuration structure */
156struct ng_one2many_config {
157  uint32_t    xmitAlg;        /* how to distribute packets */
158  uint32_t    failAlg;        /* how to detect link failure */
159  u_char      enabledLinks[NG_ONE2MANY_MAX_LINKS];
160};
161.Ed
162.Pp
163Currently, the valid settings for the
164.Dv xmitAlg
165field are
166.Dv NG_ONE2MANY_XMIT_ROUNDROBIN
167(default) or
168.Dv NG_ONE2MANY_XMIT_ALL .
169The valid settings for
170.Dv failAlg
171are
172.Dv NG_ONE2MANY_FAIL_MANUAL
173(default) or
174.Dv NG_ONE2MANY_FAIL_NOTIFY .
175.It Dv NGM_ONE2MANY_GET_CONFIG Pq Ic getconfig
176Returns the current node configuration in a
177.Dv "struct ng_one2many_link_config" .
178.It Dv NGM_ONE2MANY_GET_STATS Pq Ic getstats
179This command takes a 32 bit link number as an argument and
180returns a
181.Dv "struct ng_one2many_link_stats"
182containing statistics for the corresponding
183.Dv many
184link, which may or may not be currently connected:
185.Bd -literal
186/* Statistics structure (one for each link) */
187struct ng_one2many_link_stats {
188  uint64_t   recvOctets;     /* total octets rec'd on link */
189  uint64_t   recvPackets;    /* total pkts rec'd on link */
190  uint64_t   xmitOctets;     /* total octets xmit'd on link */
191  uint64_t   xmitPackets;    /* total pkts xmit'd on link */
192  uint64_t   memoryFailures; /* times couldn't get mem or mbuf */
193};
194.Ed
195.Pp
196To access statistics for the
197.Dv one
198link, use the link number
199.Dv -1 .
200.It Dv NGM_ONE2MANY_CLR_STATS Pq Ic clrstats
201This command takes a 32 bit link number as an argument and
202clears the statistics for that link.
203.It Dv NGM_ONE2MANY_GETCLR_STATS Pq Ic getclrstats
204Same as
205.Dv NGM_ONE2MANY_GET_STATS ,
206but also atomically clears the statistics for the link as well.
207.El
208.Sh SHUTDOWN
209This node shuts down upon receipt of a
210.Dv NGM_SHUTDOWN
211control message, or when all hooks have been disconnected.
212.Sh EXAMPLES
213The following commands will set up Ethernet interfaces
214.Dv fxp0
215to deliver packets alternating over the physical interfaces
216corresponding to networking interfaces
217.Dv fxp0
218through
219.Dv fxp3 :
220.Bd -literal
221  # Plumb nodes together
222
223  ngctl mkpeer fxp0: one2many upper one
224  ngctl connect fxp0: fxp0:upper lower many0
225  ngctl connect fxp1: fxp0:upper lower many1
226  ngctl connect fxp2: fxp0:upper lower many2
227  ngctl connect fxp3: fxp0:upper lower many3
228
229  # Allow fxp1 through fxp3 to xmit/recv fxp0 frames
230
231  ngctl msg fxp1: setpromisc 1
232  ngctl msg fxp2: setpromisc 1
233  ngctl msg fxp3: setpromisc 1
234  ngctl msg fxp1: setautosrc 0
235  ngctl msg fxp2: setautosrc 0
236  ngctl msg fxp3: setautosrc 0
237
238  # Configure all four links as up
239
240  ngctl msg fxp0:upper \\
241    setconfig "{ xmitAlg=1 failAlg=1 enabledLinks=[ 1 1 1 1 ] }"
242
243  # Bring up interface
244
245  ifconfig fxp0 192.168.1.1 netmask 0xfffffffc
246.Ed
247.Pp
248With a similar setup on a peer machine (using the address
249192.168.1.2), a point-to-point
250Ethernet connection with four times normal bandwidth is
251achieved.
252.Sh SEE ALSO
253.Xr netgraph 4 ,
254.Xr ng_bridge 4 ,
255.Xr ng_ether 4 ,
256.Xr ng_hub 4 ,
257.Xr ifconfig 8 ,
258.Xr ngctl 8
259.Sh HISTORY
260The
261.Nm
262node type was implemented in
263.Fx 4.2 .
264.Sh AUTHORS
265.An -nosplit
266The
267.Nm one2many
268netgraph node (with round-robin algorithm) was written by
269.An Archie Cobbs Aq Mt archie@FreeBSD.org .
270The all algorithm was added by
271.An Rogier R. Mulhuijzen Aq Mt drwilco@drwilco.net .
272.Sh BUGS
273More transmit and link failure algorithms should be supported.
274A good candidate is Cisco's Etherchannel.
275