xref: /freebsd/share/man/man4/ng_ksocket.4 (revision 2008043f386721d58158e37e0d7e50df8095942d)
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33.\" Author: Archie Cobbs <archie@FreeBSD.org>
34.\"
35.Dd January 9, 2012
36.Dt NG_KSOCKET 4
37.Os
38.Sh NAME
39.Nm ng_ksocket
40.Nd kernel socket netgraph node type
41.Sh SYNOPSIS
42.In sys/types.h
43.In netgraph/ng_ksocket.h
44.Sh DESCRIPTION
45A
46.Nm ksocket
47node is both a netgraph node and a
48.Bx
49socket.
50The
51.Nm
52node type allows one to open a socket inside the kernel and have
53it appear as a Netgraph node.
54The
55.Nm
56node type is the reverse of the socket node type (see
57.Xr ng_socket 4 ) :
58whereas the socket node type enables the user-level manipulation (via
59a socket) of what is normally a kernel-level entity (the associated
60Netgraph node), the
61.Nm
62node type enables the kernel-level manipulation (via a Netgraph node) of
63what is normally a user-level entity (the associated socket).
64.Pp
65A
66.Nm
67node allows at most one hook connection.
68Connecting to the node is
69equivalent to opening the associated socket.
70The name given to the hook
71determines what kind of socket the node will open (see below).
72When the hook is disconnected and/or the node is shutdown, the
73associated socket is closed.
74.Sh HOOKS
75This node type supports a single hook connection at a time.
76The name of the hook must be of the form
77.Em <family>/<type>/<proto> ,
78where the
79.Em family ,
80.Em type ,
81and
82.Em proto
83are the decimal equivalent of the same arguments to
84.Xr socket 2 .
85Alternately, aliases for the commonly used values are accepted as
86well.
87For example
88.Dv inet/dgram/udp
89is a more readable but equivalent version of
90.Dv 2/2/17 .
91.Pp
92Data received into socket is sent out via hook.
93Data received on hook is sent out from socket, if the latter is
94connected (an
95.Dv NGM_KSOCKET_CONNECT
96was sent to node before).
97If socket is not connected, destination
98.Vt "struct sockaddr"
99must be supplied in an mbuf tag with cookie
100.Dv NGM_KSOCKET_COOKIE
101and type
102.Dv NG_KSOCKET_TAG_SOCKADDR
103attached to data.
104Otherwise
105.Nm
106will return
107.Er ENOTCONN
108to sender.
109.Sh CONTROL MESSAGES
110This node type supports the generic control messages, plus the following:
111.Bl -tag -width foo
112.It Dv NGM_KSOCKET_BIND Pq Ic bind
113This functions exactly like the
114.Xr bind 2
115system call.
116The
117.Vt "struct sockaddr"
118socket address parameter should be supplied as an argument.
119.It Dv NGM_KSOCKET_LISTEN Pq Ic listen
120This functions exactly like the
121.Xr listen 2
122system call.
123The backlog parameter (a single 32 bit
124.Dv int )
125should be supplied as an argument.
126.It Dv NGM_KSOCKET_CONNECT Pq Ic connect
127This functions exactly like the
128.Xr connect 2
129system call.
130The
131.Vt "struct sockaddr"
132destination address parameter should be supplied as an argument.
133.It Dv NGM_KSOCKET_ACCEPT Pq Ic accept
134Equivalent to the
135.Xr accept 2
136system call on a non-blocking socket.
137If there is a pending connection on the queue,
138a new socket and a corresponding cloned node are created.
139Returned are the cloned node's ID and a peer name (as
140.Vt "struct sockaddr" ) .
141If there are no pending connections,
142this control message returns nothing,
143and a connected node will receive the above message asynchronously,
144when a connection is established.
145.Pp
146A cloned node supports a single hook with an arbitrary name.
147If not connected, a node disappears when its parent node is destroyed.
148Once connected, it becomes an independent node.
149.It Dv NGM_KSOCKET_GETNAME Pq Ic getname
150Equivalent to the
151.Xr getsockname 2
152system call.
153The name is returned as a
154.Vt "struct sockaddr"
155in the arguments field of the reply.
156.It Dv NGM_KSOCKET_GETPEERNAME Pq Ic getpeername
157Equivalent to the
158.Xr getpeername 2
159system call.
160The name is returned as a
161.Vt "struct sockaddr"
162in the arguments field of the reply.
163.It Dv NGM_KSOCKET_SETOPT Pq Ic setopt
164Equivalent to the
165.Xr setsockopt 2
166system call, except that the option name, level, and value are passed in a
167.Vt "struct ng_ksocket_sockopt" .
168.It Dv NGM_KSOCKET_GETOPT Pq Ic getopt
169Equivalent to the
170.Xr getsockopt 2
171system call, except that the option is passed in a
172.Vt "struct ng_ksocket_sockopt" .
173When sending this command, the
174.Dv value
175field should be empty; upon return, it will contain the
176retrieved value.
177.El
178.Sh ASCII FORM CONTROL MESSAGES
179For control messages that pass a
180.Vt "struct sockaddr"
181in the argument field, the normal
182.Tn ASCII
183equivalent of the C structure
184is an acceptable form.
185For the
186.Dv PF_INET
187and
188.Dv PF_LOCAL
189address families, a more convenient form is also used, which is
190the protocol family name, followed by a slash, followed by the actual
191address.
192For
193.Dv PF_INET ,
194the address is an IP address followed by an optional colon and port number.
195For
196.Dv PF_LOCAL ,
197the address is the pathname as a doubly quoted string.
198.Pp
199Examples:
200.Bl -tag -width "PF_LOCAL"
201.It Dv PF_LOCAL
202local/"/tmp/foo.socket"
203.It Dv PF_INET
204inet/192.168.1.1:1234
205.It Other
206.Dv "\&{ family=16 len=16 data=[0x70 0x00 0x01 0x23] \&}"
207.El
208.Pp
209For control messages that pass a
210.Vt "struct ng_ksocket_sockopt" ,
211the normal
212.Tn ASCII
213form for that structure is used.
214In the future, more
215convenient encoding of the more common socket options may be supported.
216.Pp
217Setting socket options example:
218.Bl -tag -width "PF_LOCAL"
219.It Set FIB 2 for a socket (SOL_SOCKET, SO_SETFIB):
220.Dv "setopt \&{ level=0xffff name=0x1014 data=[ 2 ] \&}"
221.El
222.Sh SHUTDOWN
223This node shuts down upon receipt of a
224.Dv NGM_SHUTDOWN
225control message, or when the hook is disconnected.
226Shutdown of the node closes the associated socket.
227.Sh SEE ALSO
228.Xr socket 2 ,
229.Xr netgraph 4 ,
230.Xr ng_socket 4 ,
231.Xr ngctl 8 ,
232.Xr mbuf_tags 9 ,
233.Xr socket 9
234.Sh HISTORY
235The
236.Nm
237node type was implemented in
238.Fx 4.0 .
239.Sh AUTHORS
240.An Archie Cobbs Aq Mt archie@FreeBSD.org
241