xref: /minix/external/bsd/dhcp/dist/dhcpctl/dhcpctl.3 (revision fb9c64b2) 
1.\"	$NetBSD: dhcpctl.3,v 1.1.1.3 2014/07/12 11:57:51 spz Exp $
2.\"
3.\" -*- nroff -*-
4.\"
5.\" Project:      DHCP
6.\" File:         dhcpctl.3
7.\" RCSId:        Id: dhcpctl.3,v 1.9 2011/04/25 23:43:16 sar Exp
8.\"
9.\" Copyright (c) 2011,2014 by Internet Systems Consortium, Inc. ("ISC")
10.\" Copyright (c) 2004,2009 by Internet Systems Consortium, Inc. ("ISC")
11.\" Copyright (c) 2000-2003 by Internet Software Consortium
12.\" Copyright (c) 2000 Nominum, Inc.
13.\"
14.\" Permission to use, copy, modify, and distribute this software for any
15.\" purpose with or without fee is hereby granted, provided that the above
16.\" copyright notice and this permission notice appear in all copies.
17.\"
18.\" THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
19.\" WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
20.\" MERCHANTABILITY AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR
21.\" ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
22.\" WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
23.\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
24.\" OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
25.\"
26.\"   Internet Systems Consortium, Inc.
27.\"   950 Charter Street
28.\"   Redwood City, CA 94063
29.\"   <info@isc.org>
30.\"   https://www.isc.org/
31.\"
32.\" Description:	dhcpctl man page.
33.\"
34.\"
35.Dd Nov 15, 2000
36.Dt DHCPCTL 3
37.Os DHCP 3
38.ds vT DHCP Programmer's Manual
39.\"
40.\"
41.\"
42.Sh NAME
43.Nm dhcpctl_initialize
44.Nd dhcpctl library initialization.
45.\"
46.\"
47.\"
48.Sh SYNOPSIS
49.Fd #include <dhcpctl/dhcpctl.h>
50.Ft dhcpctl_status
51.Fo dhcpctl_initialize
52.Fa void
53.Fc
54.\"
55.Ft dhcpctl_status
56.Fo dhcpctl_connect
57.Fa "dhcpctl_handle *cxn"
58.Fa "const char *host"
59.Fa "int port"
60.Fa "dhcpctl_handle auth"
61.Fc
62.\"
63.\"
64.\"
65.Ft dhcpctl_status
66.Fo dhcpctl_wait_for_completion
67.Fa "dhcpctl_handle object"
68.Fa "dhcpctl_status *status"
69.Fc
70.\"
71.\"
72.\"
73.Ft dhcpctl_status
74.Fo dhcpctl_get_value
75.Fa "dhcpctl_data_string *value"
76.Fa "dhcpctl_handle object"
77.Fa "const char *name"
78.Fc
79.\"
80.\"
81.\"
82.Ft dhcpctl_status
83.Fo dhcpctl_get_boolean
84.Fa "int *value"
85.Fa "dhcpctl_handle object"
86.Fa "const char *name"
87.Fc
88.\"
89.\"
90.\"
91.Ft dhcpctl_status
92.Fo dhcpctl_set_value
93.Fa "dhcpctl_handle object"
94.Fa "dhcpctl_data_string value"
95.Fa "const char *name"
96.Fc
97.\"
98.\"
99.\"
100.Ft dhcpctl_status
101.Fo dhcpctl_set_string_value
102.Fa "dhcpctl_handle object"
103.Fa "const char *value"
104.Fa "const char *name"
105.Fc
106.\"
107.\"
108.\"
109.Ft dhcpctl_status
110.Fo dhcpctl_set_boolean_value
111.Fa "dhcpctl_handle object"
112.Fa "int value"
113.Fa "const char *name"
114.Fc
115.\"
116.\"
117.\"
118.Ft dhcpctl_status
119.Fo dhcpctl_set_int_value
120.Fa "dhcpctl_handle object"
121.Fa "int value"
122.Fa "const char *name"
123.Fc
124.\"
125.\"
126.\"
127.Ft dhcpctl_status
128.Fo dhcpctl_object_update
129.Fa "dhcpctl_handle connection"
130.Fa "dhcpctl_handle object"
131.Fc
132.\"
133.\"
134.\"
135.Ft dhcpctl_status
136.Fo dhcpctl_object_refresh
137.Fa "dhcpctl_handle connection"
138.Fa "dhcpctl_handle object"
139.Fc
140.\"
141.\"
142.\"
143.Ft dhcpctl_status
144.Fo dhcpctl_object_remove
145.Fa "dhcpctl_handle connection"
146.Fa "dhcpctl_handle object"
147.Fc
148.\"
149.\"
150.\"
151.Ft dhcpctl_status
152.Fo dhcpctl_set_callback
153.Fa "dhcpctl_handle object"
154.Fa "void *data"
155.Fa "void (*function) (dhcpctl_handle, dhcpctl_status, void *)"
156.Fc
157.\"
158.\"
159.\"
160.Ft dhcpctl_status
161.Fo dhcpctl_new_authenticator
162.Fa "dhcpctl_handle *object"
163.Fa "const char *name"
164.Fa "const char *algorithm"
165.Fa "const char *secret"
166.Fa "unsigned secret_len"
167.Fc
168.\"
169.\"
170.\"
171.Ft dhcpctl_status
172.Fo dhcpctl_new_object
173.Fa "dhcpctl_handle *object"
174.Fa "dhcpctl_handle connection"
175.Fa "const char *object_type"
176.Fc
177.\"
178.\"
179.\"
180.Ft dhcpctl_status
181.Fo dhcpctl_open_object
182.Fa "dhcpctl_handle object"
183.Fa "dhcpctl_handle connection"
184.Fa "int flags"
185.Fc
186.\"
187.\"
188.\"
189.Ft isc_result_t
190.Fo omapi_data_string_new
191.Fa dhcpctl_data_string *data
192.Fa unsigned int length
193.Fa const char *filename,
194.Fa int lineno
195.Fc
196.\"
197.\"
198.\"
199.Ft isc_result_t
200.Fo dhcpctl_data_string_dereference
201.Fa "dhcpctl_data_string *"
202.Fa "const char *"
203.Fa "int"
204.Fc
205.Sh DESCRIPTION
206The dhcpctl set of functions provide an API that can be used to communicate
207with and manipulate a running ISC DHCP server. All functions return a value of
208.Dv isc_result_t .
209The return values reflects the result of operations to local data
210structures. If an operation fails on the server for any reason, then the error
211result will be returned through the
212second parameter of the
213.Fn dhcpctl_wait_for_completion
214call.
215.\"
216.\"
217.\"
218.Pp
219.Fn dhcpctl_initialize
220sets up the data structures the library needs to do its work. This function
221must be called once before any other.
222.Pp
223.Fn dhcpctl_connect
224opens a connection to the DHCP server at the given host and port. If an
225authenticator has been created for the connection, then it is given as the 4th
226argument. On a successful return the address pointed at by the first
227argument will have a new connection object assigned to it.
228.Pp
229For example:
230.Bd -literal -offset indent
231s = dhcpctl_connect(&cxn, "127.0.0.1", 7911, NULL);
232.Ed
233.Pp
234connects to the DHCP server on the localhost via port 7911 (the standard
235OMAPI port). No authentication is used for the connection.
236.\"
237.\"
238.\"
239.Pp
240.Fn dhcpctl_wait_for_completion
241flushes a pending message to the server and waits for the response. The result
242of the request as processed on the server is returned via the second
243parameter.
244.Bd -literal -offset indent
245s = dhcpctl_wait_for_completion(cxn, &wv);
246if (s != ISC_R_SUCCESS)
247	local_failure(s);
248else if (wv != ISC_R_SUCCESS)
249	server_failure(wc);
250.Ed
251.Pp
252The call to
253.Fn dhcpctl_wait_for_completion
254won't return until the remote message processing completes or the connection
255to the server is lost.
256.\"
257.\"
258.\"
259.Pp
260.Fn dhcpctl_get_value
261extracts a value of an attribute from the handle. The value can be of any
262length and is treated as a sequence of bytes.  The handle must have been
263created first with
264.Fn dhcpctl_new_object
265and opened with
266.Fn dhcpctl_open_object .
267The value is returned via the parameter named
268.Dq value .
269The last parameter is the name of attribute to retrieve.
270.Bd -literal -offset indent
271dhcpctl_data_string value = NULL;
272dhcpctl_handle lease;
273time_t thetime;
274
275s = dhcpctl_get_value (&value, lease, "ends");
276assert(s == ISC_R_SUCCESS && value->len == sizeof(thetime));
277memcpy(&thetime, value->value, value->len);
278.Ed
279.\"
280.\"
281.\"
282.Pp
283.Fn dhcpctl_get_boolean
284extracts a boolean valued attribute from the object handle.
285.\"
286.\"
287.\"
288.Pp
289The
290.Fn dhcpctl_set_value ,
291.Fn dhcpctl_set_string_value ,
292.Fn dhcpctl_set_boolean_value ,
293and
294.Fn dhcpctl_set_int_value
295functions all set a value on the object handle.
296.\"
297.\"
298.\"
299.Pp
300.Fn dhcpctl_object_update
301function queues a request for
302all the changes made to the object handle be sent to the remote
303for processing. The changes made to the attributes on the handle will be
304applied to remote object if permitted.
305.\"
306.\"
307.\"
308.Pp
309.Fn dhcpctl_object_refresh
310queues up a request for a fresh copy of all the attribute values to be sent
311from the remote to
312refresh the values in the local object handle.
313.\"
314.\"
315.\"
316.Pp
317.Fn dhcpctl_object_remove
318queues a request for the removal on the server of the object referenced by the
319handle.
320.\"
321.\"
322.\"
323.Pp
324The
325.Fn dhcpctl_set_callback
326function sets up a user-defined function to be called when an event completes
327on the given object handle. This is needed for asynchronous handling of
328events, versus the synchronous handling given by
329.Fn dhcpctl_wait_for_completion .
330When the function is called the first parameter is the object the event
331arrived for, the second is the status of the message that was processed, the
332third is the same value as the second parameter given to
333.Fn dhcpctl_set_callback .
334.\"
335.\"
336.\"
337.Pp
338The
339.Fn dhcpctl_new_authenticator
340creates a new authenticator object to be used for signing the messages
341that cross over the network. The
342.Dq name ,
343.Dq algorithm ,
344and
345.Dq secret
346values must all match what the server uses and are defined in its
347configuration file. The created object is returned through the first parameter
348and must be used as the 4th parameter to
349.Fn dhcpctl_connect .
350Note that the 'secret' value must not be base64 encoded, which is different
351from how the value appears in the dhcpd.conf file.
352.\"
353.\"
354.\"
355.Pp
356.Fn dhcpctl_new_object
357creates a local handle for an object on the server. The
358.Dq object_type
359parameter is the ascii name of the type of object being accessed. e.g.
360.Qq lease .
361This function only sets up local data structures, it does not queue any
362messages
363to be sent to the remote side,
364.Fn dhcpctl_open_object
365does that.
366.\"
367.\"
368.\"
369.Pp
370.Fn dhcpctl_open_object
371builds and queues the request to the remote side. This function is used with
372handle created via
373.Fn dhcpctl_new_object .
374The flags argument is a bit mask with the following values available for
375setting:
376.Bl -tag -offset indent -width 20
377.It DHCPCTL_CREATE
378if the object does not exist then the remote will create it
379.It DHCPCTL_UPDATE
380update the object on the remote side using the
381attributes already set in the handle.
382.It DHCPCTL_EXCL
383return and error if the object exists and DHCPCTL_CREATE
384was also specified
385.El
386.\"
387.\"
388.\"
389.Pp
390The
391.Fn omapi_data_string_new
392function allocates a new
393.Ft dhcpctl_data_string
394object. The data string will be large enough to hold
395.Dq length
396bytes of data. The
397.Dq file
398and
399.Dq lineno
400arguments are the source file location the call is made from, typically by
401using the
402.Dv __FILE__
403and
404.Dv __LINE__
405macros or the
406.Dv MDL
407macro defined in
408.
409.\"
410.\"
411.\"
412.Pp
413.Fn dhcpctl_data_string_dereference
414deallocates a data string created by
415.Fn omapi_data_string_new .
416The memory for the object won't be freed until the last reference is
417released.
418.Sh EXAMPLES
419.Pp
420The following program will connect to the DHCP server running on the local
421host and will get the details of the existing lease for IP address
42210.0.0.101. It will then print out the time the lease is due to expire. Note
423that most error checking has been omitted for brevity.
424.Bd -literal -offset indent
425#include <sys/time.h>
426#include <stdio.h>
427#include <stdlib.h>
428#include <string.h>
429#include <stdarg.h>
430
431#include <sys/socket.h>
432#include <netinet/in.h>
433#include <arpa/inet.h>
434
435#include "omapip/result.h"
436#include "dhcpctl.h"
437
438int main (int argc, char **argv) {
439	dhcpctl_data_string ipaddrstring = NULL;
440	dhcpctl_data_string value = NULL;
441	dhcpctl_handle connection = NULL;
442	dhcpctl_handle lease = NULL;
443	isc_result_t waitstatus;
444	struct in_addr convaddr;
445	time_t thetime;
446
447        dhcpctl_initialize ();
448
449        dhcpctl_connect (&connection, "127.0.0.1",
450			 7911, 0);
451
452        dhcpctl_new_object (&lease, connection,
453			    "lease");
454
455        memset (&ipaddrstring, 0, sizeof
456		ipaddrstring);
457
458        inet_pton(AF_INET, "10.0.0.101",
459		  &convaddr);
460
461	omapi_data_string_new (&ipaddrstring,
462			       4, MDL);
463	memcpy(ipaddrstring->value, &convaddr.s_addr, 4);
464
465	dhcpctl_set_value (lease, ipaddrstring,
466			   "ip-address");
467
468	dhcpctl_open_object (lease, connection, 0);
469
470	dhcpctl_wait_for_completion (lease,
471				     &waitstatus);
472        if (waitstatus != ISC_R_SUCCESS) {
473		/* server not authoritative */
474		exit (0);
475        }
476
477	dhcpctl_data_string_dereference(&ipaddrstring,
478					MDL);
479
480        dhcpctl_get_value (&value, lease, "ends");
481
482	memcpy(&thetime, value->value, value->len);
483
484	dhcpctl_data_string_dereference(&value, MDL);
485
486	fprintf (stdout, "ending time is %s",
487		 ctime(&thetime));
488}
489.Ed
490.Sh SEE ALSO
491omapi(3), omshell(1), dhcpd(8), dhclient(8), dhcpd.conf(5), dhclient.conf(5).
492.Sh AUTHOR
493.Em dhcpctl
494is maintained by ISC.  To learn more about Internet Systems Consortium,
495see
496.B https://www.isc.org
497
498