1 /*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License (the "License").
6 * You may not use this file except in compliance with the License.
7 *
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://www.opensolaris.org/os/licensing.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
12 *
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
18 *
19 * CDDL HEADER END
20 */
21 /*
22 * Copyright 2009 Sun Microsystems, Inc. All rights reserved.
23 * Use is subject to license terms.
24 */
25
26 #include <string.h>
27 #include <unistd.h>
28 #include <stdlib.h>
29 #include <sys/uio.h>
30 #include <sys/socket.h>
31 #include <sys/types.h>
32 #include <fcntl.h>
33 #include <errno.h>
34 #include <limits.h>
35 #include <netinet/in.h>
36 #include <netinet/tcp.h>
37 #include <net/if.h>
38 #include <sys/sockio.h>
39 #include <sys/fcntl.h>
40 #include <sys/time.h>
41 #include <stdio.h> /* snprintf */
42 #include <arpa/inet.h> /* ntohl, ntohs, etc */
43
44 #include "dhcpagent_ipc.h"
45 #include "dhcpagent_util.h"
46
47 /*
48 * the protocol used here is a simple request/reply scheme: a client
49 * sends a dhcp_ipc_request_t message to the agent, and the agent
50 * sends a dhcp_ipc_reply_t back to the client. since the requests
51 * and replies can be variable-length, they are prefixed on "the wire"
52 * by a 32-bit number that tells the other end how many bytes to
53 * expect.
54 *
55 * the format of a request consists of a single dhcp_ipc_request_t;
56 * note that the length of this dhcp_ipc_request_t is variable (using
57 * the standard c array-of-size-1 trick). the type of the payload is
58 * given by `data_type', which is guaranteed to be `data_length' bytes
59 * long starting at `buffer'. note that `buffer' is guaranteed to be
60 * 32-bit aligned but it is poor taste to rely on this.
61 *
62 * the format of a reply is much the same: a single dhcp_ipc_reply_t;
63 * note again that the length of the dhcp_ipc_reply_t is variable.
64 * the type of the payload is given by `data_type', which is
65 * guaranteed to be `data_length' bytes long starting at `buffer'.
66 * once again, note that `buffer' is guaranteed to be 32-bit aligned
67 * but it is poor taste to rely on this.
68 *
69 * requests and replies can be paired up by comparing `ipc_id' fields.
70 */
71
72 #define BUFMAX 256
73
74 static int dhcp_ipc_timed_read(int, void *, unsigned int, int *);
75 static int getinfo_ifnames(const char *, dhcp_optnum_t *, DHCP_OPT **);
76 static char *get_ifnames(int, int);
77
78 /* must be kept in sync with enum in dhcpagent_ipc.h */
79 static const char *ipc_typestr[] = {
80 "drop", "extend", "ping", "release", "start", "status",
81 "inform", "get_tag"
82 };
83
84 /*
85 * dhcp_ipc_alloc_request(): allocates a dhcp_ipc_request_t of the given type
86 * and interface, with a timeout of 0.
87 *
88 * input: dhcp_ipc_type_t: the type of ipc request to allocate
89 * const char *: the interface to associate the request with
90 * const void *: the payload to send with the message (NULL if none)
91 * uint32_t: the payload size (0 if none)
92 * dhcp_data_type_t: the description of the type of payload
93 * output: dhcp_ipc_request_t *: the request on success, NULL on failure
94 */
95
96 dhcp_ipc_request_t *
97 dhcp_ipc_alloc_request(dhcp_ipc_type_t type, const char *ifname,
98 const void *buffer, uint32_t buffer_size, dhcp_data_type_t data_type)
99 {
100 dhcp_ipc_request_t *request = calloc(1, DHCP_IPC_REQUEST_SIZE +
101 buffer_size);
102
103 if (request == NULL)
104 return (NULL);
105
106 request->message_type = type;
107 request->data_length = buffer_size;
108 request->data_type = data_type;
109
110 if (ifname != NULL)
111 (void) strlcpy(request->ifname, ifname, LIFNAMSIZ);
112
113 if (buffer != NULL)
114 (void) memcpy(request->buffer, buffer, buffer_size);
115
116 return (request);
117 }
118
119 /*
120 * dhcp_ipc_alloc_reply(): allocates a dhcp_ipc_reply_t
121 *
122 * input: dhcp_ipc_request_t *: the request the reply is for
123 * int: the return code (0 for success, DHCP_IPC_E_* otherwise)
124 * const void *: the payload to send with the message (NULL if none)
125 * uint32_t: the payload size (0 if none)
126 * dhcp_data_type_t: the description of the type of payload
127 * output: dhcp_ipc_reply_t *: the reply on success, NULL on failure
128 */
129
130 dhcp_ipc_reply_t *
131 dhcp_ipc_alloc_reply(dhcp_ipc_request_t *request, int return_code,
132 const void *buffer, uint32_t buffer_size, dhcp_data_type_t data_type)
133 {
134 dhcp_ipc_reply_t *reply = calloc(1, DHCP_IPC_REPLY_SIZE + buffer_size);
135
136 if (reply == NULL)
137 return (NULL);
138
139 reply->message_type = request->message_type;
140 reply->ipc_id = request->ipc_id;
141 reply->return_code = return_code;
142 reply->data_length = buffer_size;
143 reply->data_type = data_type;
144
145 if (buffer != NULL)
146 (void) memcpy(reply->buffer, buffer, buffer_size);
147
148 return (reply);
149 }
150
151 /*
152 * dhcp_ipc_get_data(): gets the data and data type from a dhcp_ipc_reply_t
153 *
154 * input: dhcp_ipc_reply_t *: the reply to get data from
155 * size_t *: the size of the resulting data
156 * dhcp_data_type_t *: the type of the message (returned)
157 * output: void *: a pointer to the data, if there is any.
158 */
159
160 void *
161 dhcp_ipc_get_data(dhcp_ipc_reply_t *reply, size_t *size, dhcp_data_type_t *type)
162 {
163 if (reply == NULL || reply->data_length == 0) {
164 *size = 0;
165 return (NULL);
166 }
167
168 if (type != NULL)
169 *type = reply->data_type;
170
171 *size = reply->data_length;
172 return (reply->buffer);
173 }
174
175 /*
176 * dhcp_ipc_recv_msg(): gets a message using the agent's ipc protocol
177 *
178 * input: int: the file descriptor to get the message from
179 * void **: the address of a pointer to store the message
180 * (dynamically allocated)
181 * uint32_t: the minimum length of the packet
182 * int: the # of milliseconds to wait for the message (-1 is forever)
183 * output: int: DHCP_IPC_SUCCESS on success, DHCP_IPC_E_* otherwise
184 */
185
186 static int
187 dhcp_ipc_recv_msg(int fd, void **msg, uint32_t base_length, int msec)
188 {
189 int retval;
190 dhcp_ipc_reply_t *ipc_msg;
191 uint32_t length;
192
193 retval = dhcp_ipc_timed_read(fd, &length, sizeof (uint32_t), &msec);
194 if (retval != DHCP_IPC_SUCCESS)
195 return (retval);
196
197 if (length == 0)
198 return (DHCP_IPC_E_PROTO);
199
200 *msg = malloc(length);
201 if (*msg == NULL)
202 return (DHCP_IPC_E_MEMORY);
203
204 retval = dhcp_ipc_timed_read(fd, *msg, length, &msec);
205 if (retval != DHCP_IPC_SUCCESS) {
206 free(*msg);
207 return (retval);
208 }
209
210 if (length < base_length) {
211 free(*msg);
212 return (DHCP_IPC_E_PROTO);
213 }
214
215 /*
216 * the data_length field is in the same place in either ipc message.
217 */
218
219 ipc_msg = (dhcp_ipc_reply_t *)(*msg);
220 if (ipc_msg->data_length + base_length != length) {
221 free(*msg);
222 return (DHCP_IPC_E_PROTO);
223 }
224
225 return (DHCP_IPC_SUCCESS);
226 }
227
228 /*
229 * dhcp_ipc_recv_request(): gets a request using the agent's ipc protocol
230 *
231 * input: int: the file descriptor to get the message from
232 * dhcp_ipc_request_t **: address of a pointer to store the request
233 * (dynamically allocated)
234 * int: the # of milliseconds to wait for the message (-1 is forever)
235 * output: int: 0 on success, DHCP_IPC_E_* otherwise
236 */
237
238 int
239 dhcp_ipc_recv_request(int fd, dhcp_ipc_request_t **request, int msec)
240 {
241 int retval;
242
243 retval = dhcp_ipc_recv_msg(fd, (void **)request, DHCP_IPC_REQUEST_SIZE,
244 msec);
245
246 /* guarantee that ifname will be NUL-terminated */
247 if (retval == 0)
248 (*request)->ifname[LIFNAMSIZ - 1] = '\0';
249
250 return (retval);
251 }
252
253 /*
254 * dhcp_ipc_recv_reply(): gets a reply using the agent's ipc protocol
255 *
256 * input: int: the file descriptor to get the message from
257 * dhcp_ipc_reply_t **: address of a pointer to store the reply
258 * (dynamically allocated)
259 * int32_t: timeout (in seconds), or DHCP_IPC_WAIT_FOREVER,
260 * or DHCP_IPC_WAIT_DEFAULT
261 * output: int: 0 on success, DHCP_IPC_E_* otherwise
262 */
263
264 static int
265 dhcp_ipc_recv_reply(int fd, dhcp_ipc_reply_t **reply, int32_t timeout)
266 {
267 /*
268 * If the caller doesn't want to wait forever, and the amount of time
269 * he wants to wait is expressible as an integer number of milliseconds
270 * (as needed by the msg function), then we wait that amount of time
271 * plus an extra two seconds for the daemon to do its work. The extra
272 * two seconds is arbitrary; it should allow plenty of time for the
273 * daemon to respond within the existing timeout, as specified in the
274 * original request, so the only time we give up is when the daemon is
275 * stopped or otherwise malfunctioning.
276 *
277 * Note that the wait limit (milliseconds in an 'int') is over 24 days,
278 * so it's unlikely that any request will actually be that long, and
279 * it's unlikely that anyone will care if we wait forever on a request
280 * for a 30 day timer. The point is to protect against daemon
281 * malfunction in the usual cases, not to provide an absolute command
282 * timer.
283 */
284 if (timeout == DHCP_IPC_WAIT_DEFAULT)
285 timeout = DHCP_IPC_DEFAULT_WAIT;
286 if (timeout != DHCP_IPC_WAIT_FOREVER && timeout < INT_MAX / 1000 - 2)
287 timeout = (timeout + 2) * 1000;
288 else
289 timeout = -1;
290 return (dhcp_ipc_recv_msg(fd, (void **)reply, DHCP_IPC_REPLY_SIZE,
291 timeout));
292 }
293
294 /*
295 * dhcp_ipc_send_msg(): transmits a message using the agent's ipc protocol
296 *
297 * input: int: the file descriptor to transmit on
298 * void *: the message to send
299 * uint32_t: the message length
300 * output: int: 0 on success, DHCP_IPC_E_* otherwise
301 */
302
303 static int
304 dhcp_ipc_send_msg(int fd, void *msg, uint32_t message_length)
305 {
306 struct iovec iovec[2];
307
308 iovec[0].iov_base = (caddr_t)&message_length;
309 iovec[0].iov_len = sizeof (uint32_t);
310 iovec[1].iov_base = msg;
311 iovec[1].iov_len = message_length;
312
313 if (writev(fd, iovec, sizeof (iovec) / sizeof (*iovec)) == -1)
314 return (DHCP_IPC_E_WRITEV);
315
316 return (0);
317 }
318
319 /*
320 * dhcp_ipc_send_reply(): transmits a reply using the agent's ipc protocol
321 *
322 * input: int: the file descriptor to transmit on
323 * dhcp_ipc_reply_t *: the reply to send
324 * output: int: 0 on success, DHCP_IPC_E_* otherwise
325 */
326
327 int
328 dhcp_ipc_send_reply(int fd, dhcp_ipc_reply_t *reply)
329 {
330 return (dhcp_ipc_send_msg(fd, reply, DHCP_IPC_REPLY_SIZE +
331 reply->data_length));
332 }
333
334 /*
335 * dhcp_ipc_send_request(): transmits a request using the agent's ipc protocol
336 *
337 * input: int: the file descriptor to transmit on
338 * dhcp_ipc_request_t *: the request to send
339 * output: int: 0 on success, DHCP_IPC_E_* otherwise
340 */
341
342 static int
343 dhcp_ipc_send_request(int fd, dhcp_ipc_request_t *request)
344 {
345 /*
346 * for now, ipc_ids aren't really used, but they're intended
347 * to make it easy to send several requests and then collect
348 * all of the replies (and pair them with the requests).
349 */
350
351 request->ipc_id = gethrtime();
352
353 return (dhcp_ipc_send_msg(fd, request, DHCP_IPC_REQUEST_SIZE +
354 request->data_length));
355 }
356
357 /*
358 * dhcp_ipc_make_request(): sends the provided request to the agent and reaps
359 * the reply
360 *
361 * input: dhcp_ipc_request_t *: the request to make
362 * dhcp_ipc_reply_t **: the reply (dynamically allocated)
363 * int32_t: timeout (in seconds), or DHCP_IPC_WAIT_FOREVER,
364 * or DHCP_IPC_WAIT_DEFAULT
365 * output: int: 0 on success, DHCP_IPC_E_* otherwise
366 */
367
368 int
369 dhcp_ipc_make_request(dhcp_ipc_request_t *request, dhcp_ipc_reply_t **reply,
370 int32_t timeout)
371 {
372 int fd, on, retval;
373 struct sockaddr_in sinv;
374
375 fd = socket(AF_INET, SOCK_STREAM, 0);
376 if (fd == -1)
377 return (DHCP_IPC_E_SOCKET);
378
379 /*
380 * Bind a privileged port if we have sufficient privilege to do so.
381 * Continue as non-privileged otherwise.
382 */
383 on = 1;
384 (void) setsockopt(fd, IPPROTO_TCP, TCP_ANONPRIVBIND, &on, sizeof (on));
385
386 (void) memset(&sinv, 0, sizeof (sinv));
387 sinv.sin_family = AF_INET;
388 if (bind(fd, (struct sockaddr *)&sinv, sizeof (sinv)) == -1) {
389 (void) dhcp_ipc_close(fd);
390 return (DHCP_IPC_E_BIND);
391 }
392
393 sinv.sin_port = htons(IPPORT_DHCPAGENT);
394 sinv.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
395 retval = connect(fd, (struct sockaddr *)&sinv, sizeof (sinv));
396 if (retval == -1) {
397 (void) dhcp_ipc_close(fd);
398 return (DHCP_IPC_E_CONNECT);
399 }
400
401 request->timeout = timeout;
402
403 retval = dhcp_ipc_send_request(fd, request);
404 if (retval == 0)
405 retval = dhcp_ipc_recv_reply(fd, reply, timeout);
406
407 (void) dhcp_ipc_close(fd);
408
409 return (retval);
410 }
411
412 /*
413 * dhcp_ipc_init(): initializes the ipc channel for use by the agent
414 *
415 * input: int *: the file descriptor to accept on (returned)
416 * output: int: 0 on success, DHCP_IPC_E_* otherwise
417 */
418
419 int
420 dhcp_ipc_init(int *listen_fd)
421 {
422 struct sockaddr_in sin;
423 int on = 1;
424
425 (void) memset(&sin, 0, sizeof (struct sockaddr_in));
426
427 sin.sin_family = AF_INET;
428 sin.sin_port = htons(IPPORT_DHCPAGENT);
429 sin.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
430
431 *listen_fd = socket(AF_INET, SOCK_STREAM, 0);
432 if (*listen_fd == -1)
433 return (DHCP_IPC_E_SOCKET);
434
435 /*
436 * we use SO_REUSEADDR here since in the case where there
437 * really is another daemon running that is using the agent's
438 * port, bind(3N) will fail. so we can't lose.
439 */
440
441 (void) setsockopt(*listen_fd, SOL_SOCKET, SO_REUSEADDR, &on,
442 sizeof (on));
443
444 if (bind(*listen_fd, (struct sockaddr *)&sin, sizeof (sin)) == -1) {
445 (void) close(*listen_fd);
446 return (DHCP_IPC_E_BIND);
447 }
448
449 if (listen(*listen_fd, DHCP_IPC_LISTEN_BACKLOG) == -1) {
450 (void) close(*listen_fd);
451 return (DHCP_IPC_E_LISTEN);
452 }
453
454 return (0);
455 }
456
457 /*
458 * dhcp_ipc_accept(): accepts an incoming connection for the agent
459 *
460 * input: int: the file descriptor to accept on
461 * int *: the accepted file descriptor (returned)
462 * int *: nonzero if the client is privileged (returned)
463 * output: int: 0 on success, DHCP_IPC_E_* otherwise
464 * note: sets the socket into nonblocking mode
465 */
466
467 int
468 dhcp_ipc_accept(int listen_fd, int *fd, int *is_priv)
469 {
470 struct sockaddr_in sin_peer;
471 int sin_len = sizeof (sin_peer);
472 int sockflags;
473
474 /*
475 * if we were extremely concerned with portability, we would
476 * set the socket into nonblocking mode before doing the
477 * accept(3N), since on BSD-based networking stacks, there is
478 * a potential race that can occur if the socket which
479 * connected to us performs a TCP RST before we accept, since
480 * BSD handles this case entirely in the kernel and as a
481 * result even though select said we will not block, we can
482 * end up blocking since there is no longer a connection to
483 * accept. on SVR4-based systems, this should be okay,
484 * and we will get EPROTO back, even though POSIX.1g says
485 * we should get ECONNABORTED.
486 */
487
488 *fd = accept(listen_fd, (struct sockaddr *)&sin_peer, &sin_len);
489 if (*fd == -1)
490 return (DHCP_IPC_E_ACCEPT);
491
492 /* get credentials */
493 *is_priv = ntohs(sin_peer.sin_port) < IPPORT_RESERVED;
494
495 /*
496 * kick the socket into non-blocking mode so that later
497 * operations on the socket don't block and hold up the whole
498 * application. with the event demuxing approach, this may
499 * seem unnecessary, but in order to get partial reads/writes
500 * and to handle our internal protocol for passing data
501 * between the agent and its consumers, this is needed.
502 */
503
504 if ((sockflags = fcntl(*fd, F_GETFL, 0)) == -1) {
505 (void) close(*fd);
506 return (DHCP_IPC_E_FCNTL);
507 }
508
509 if (fcntl(*fd, F_SETFL, sockflags | O_NONBLOCK) == -1) {
510 (void) close(*fd);
511 return (DHCP_IPC_E_FCNTL);
512 }
513
514 return (0);
515 }
516
517 /*
518 * dhcp_ipc_close(): closes an ipc descriptor
519 *
520 * input: int: the file descriptor to close
521 * output: int: 0 on success, DHCP_IPC_E_* otherwise
522 */
523
524 int
525 dhcp_ipc_close(int fd)
526 {
527 return ((close(fd) == -1) ? DHCP_IPC_E_CLOSE : 0);
528 }
529
530 /*
531 * dhcp_ipc_strerror(): maps an ipc error code into a human-readable string
532 *
533 * input: int: the ipc error code to map
534 * output: const char *: the corresponding human-readable string
535 */
536
537 const char *
538 dhcp_ipc_strerror(int error)
539 {
540 /* note: this must be kept in sync with DHCP_IPC_E_* definitions */
541 const char *syscalls[] = {
542 "<unknown>", "socket", "fcntl", "read", "accept", "close",
543 "bind", "listen", "malloc", "connect", "writev", "poll"
544 };
545
546 const char *error_string;
547 static char buffer[BUFMAX];
548
549 switch (error) {
550
551 /*
552 * none of these errors actually go over the wire.
553 * hence, we assume that errno is still fresh.
554 */
555
556 case DHCP_IPC_E_SOCKET: /* FALLTHRU */
557 case DHCP_IPC_E_FCNTL: /* FALLTHRU */
558 case DHCP_IPC_E_READ: /* FALLTHRU */
559 case DHCP_IPC_E_ACCEPT: /* FALLTHRU */
560 case DHCP_IPC_E_CLOSE: /* FALLTHRU */
561 case DHCP_IPC_E_BIND: /* FALLTHRU */
562 case DHCP_IPC_E_LISTEN: /* FALLTHRU */
563 case DHCP_IPC_E_CONNECT: /* FALLTHRU */
564 case DHCP_IPC_E_WRITEV: /* FALLTHRU */
565 case DHCP_IPC_E_POLL:
566
567 error_string = strerror(errno);
568 if (error_string == NULL)
569 error_string = "unknown error";
570
571 (void) snprintf(buffer, sizeof (buffer), "%s: %s",
572 syscalls[error], error_string);
573
574 error_string = buffer;
575 break;
576
577 case DHCP_IPC_E_MEMORY:
578 error_string = "out of memory";
579 break;
580
581 case DHCP_IPC_E_TIMEOUT:
582 error_string = "wait timed out, operation still pending...";
583 break;
584
585 case DHCP_IPC_E_INVIF:
586 error_string = "interface does not exist or cannot be managed "
587 "using DHCP";
588 break;
589
590 case DHCP_IPC_E_INT:
591 error_string = "internal error (might work later)";
592 break;
593
594 case DHCP_IPC_E_PERM:
595 error_string = "permission denied";
596 break;
597
598 case DHCP_IPC_E_OUTSTATE:
599 error_string = "interface not in appropriate state for command";
600 break;
601
602 case DHCP_IPC_E_PEND:
603 error_string = "interface currently has a pending command "
604 "(try later)";
605 break;
606
607 case DHCP_IPC_E_BOOTP:
608 error_string = "interface is administered with BOOTP, not DHCP";
609 break;
610
611 case DHCP_IPC_E_CMD_UNKNOWN:
612 error_string = "unknown command";
613 break;
614
615 case DHCP_IPC_E_UNKIF:
616 error_string = "interface is not under DHCP control";
617 break;
618
619 case DHCP_IPC_E_PROTO:
620 error_string = "ipc protocol violation";
621 break;
622
623 case DHCP_IPC_E_FAILEDIF:
624 error_string = "interface is in a FAILED state and must be "
625 "manually restarted";
626 break;
627
628 case DHCP_IPC_E_NOPRIMARY:
629 error_string = "primary interface requested but no primary "
630 "interface is set";
631 break;
632
633 case DHCP_IPC_E_NOIPIF:
634 error_string = "interface currently has no IP address";
635 break;
636
637 case DHCP_IPC_E_DOWNIF:
638 error_string = "interface is currently down";
639 break;
640
641 case DHCP_IPC_E_NOVALUE:
642 error_string = "no value was found for this option";
643 break;
644
645 case DHCP_IPC_E_RUNNING:
646 error_string = "DHCP is already running";
647 break;
648
649 case DHCP_IPC_E_SRVFAILED:
650 error_string = "DHCP server refused request";
651 break;
652
653 case DHCP_IPC_E_EOF:
654 error_string = "ipc connection closed";
655 break;
656
657 default:
658 error_string = "unknown error";
659 break;
660 }
661
662 /*
663 * TODO: internationalize this error string
664 */
665
666 return (error_string);
667 }
668
669 /*
670 * dhcp_string_to_request(): maps a string into a request code
671 *
672 * input: const char *: the string to map
673 * output: dhcp_ipc_type_t: the request code, or -1 if unknown
674 */
675
676 dhcp_ipc_type_t
677 dhcp_string_to_request(const char *request)
678 {
679 unsigned int i;
680
681 for (i = 0; i < DHCP_NIPC; i++)
682 if (strcmp(ipc_typestr[i], request) == 0)
683 return ((dhcp_ipc_type_t)i);
684
685 return ((dhcp_ipc_type_t)-1);
686 }
687
688 /*
689 * dhcp_ipc_type_to_string(): maps an ipc command code into a human-readable
690 * string
691 *
692 * input: int: the ipc command code to map
693 * output: const char *: the corresponding human-readable string
694 */
695
696 const char *
697 dhcp_ipc_type_to_string(dhcp_ipc_type_t type)
698 {
699 if (type < 0 || type >= DHCP_NIPC)
700 return ("unknown");
701 else
702 return (ipc_typestr[(int)type]);
703 }
704
705 /*
706 * getinfo_ifnames(): checks the value of a specified option on a list of
707 * interface names.
708 * input: const char *: a list of interface names to query (in order) for
709 * the option; "" queries the primary interface
710 * dhcp_optnum_t *: a description of the desired option
711 * DHCP_OPT **: filled in with the (dynamically allocated) value of
712 * the option upon success.
713 * output: int: DHCP_IPC_E_* on error, 0 on success or if no value was
714 * found but no error occurred either (*result will be NULL)
715 */
716
717 static int
718 getinfo_ifnames(const char *ifn, dhcp_optnum_t *optnum, DHCP_OPT **result)
719 {
720 dhcp_ipc_request_t *request;
721 dhcp_ipc_reply_t *reply;
722 char *ifnames, *ifnames_head;
723 DHCP_OPT *opt;
724 size_t opt_size;
725 int retval = 0;
726
727 *result = NULL;
728 ifnames_head = ifnames = strdup(ifn);
729 if (ifnames == NULL)
730 return (DHCP_IPC_E_MEMORY);
731
732 request = dhcp_ipc_alloc_request(DHCP_GET_TAG, "", optnum,
733 sizeof (dhcp_optnum_t), DHCP_TYPE_OPTNUM);
734
735 if (request == NULL) {
736 free(ifnames_head);
737 return (DHCP_IPC_E_MEMORY);
738 }
739
740 ifnames = strtok(ifnames, " ");
741 if (ifnames == NULL)
742 ifnames = "";
743
744 for (; ifnames != NULL; ifnames = strtok(NULL, " ")) {
745
746 (void) strlcpy(request->ifname, ifnames, LIFNAMSIZ);
747 retval = dhcp_ipc_make_request(request, &reply, 0);
748 if (retval != 0)
749 break;
750
751 if (reply->return_code == 0) {
752 opt = dhcp_ipc_get_data(reply, &opt_size, NULL);
753 if (opt_size > 2 && (opt->len == opt_size - 2)) {
754 *result = malloc(opt_size);
755 if (*result == NULL)
756 retval = DHCP_IPC_E_MEMORY;
757 else
758 (void) memcpy(*result, opt, opt_size);
759
760 free(reply);
761 break;
762 }
763 }
764
765 free(reply);
766 if (ifnames[0] == '\0')
767 break;
768 }
769
770 free(request);
771 free(ifnames_head);
772
773 return (retval);
774 }
775
776 /*
777 * get_ifnames(): returns a space-separated list of interface names that
778 * match the specified flags
779 *
780 * input: int: flags which must be on in each interface returned
781 * int: flags which must be off in each interface returned
782 * output: char *: a dynamically-allocated list of interface names, or
783 * NULL upon failure.
784 */
785
786 static char *
787 get_ifnames(int flags_on, int flags_off)
788 {
789 struct ifconf ifc;
790 int n_ifs, i, sock_fd;
791 char *ifnames;
792
793
794 sock_fd = socket(AF_INET, SOCK_DGRAM, 0);
795 if (sock_fd == -1)
796 return (NULL);
797
798 if ((ioctl(sock_fd, SIOCGIFNUM, &n_ifs) == -1) || (n_ifs <= 0)) {
799 (void) close(sock_fd);
800 return (NULL);
801 }
802
803 ifnames = calloc(1, n_ifs * (LIFNAMSIZ + 1));
804 ifc.ifc_len = n_ifs * sizeof (struct ifreq);
805 ifc.ifc_req = calloc(n_ifs, sizeof (struct ifreq));
806 if (ifc.ifc_req != NULL && ifnames != NULL) {
807
808 if (ioctl(sock_fd, SIOCGIFCONF, &ifc) == -1) {
809 (void) close(sock_fd);
810 free(ifnames);
811 free(ifc.ifc_req);
812 return (NULL);
813 }
814
815 for (i = 0; i < n_ifs; i++) {
816
817 if (ioctl(sock_fd, SIOCGIFFLAGS, &ifc.ifc_req[i]) == 0)
818 if ((ifc.ifc_req[i].ifr_flags &
819 (flags_on | flags_off)) != flags_on)
820 continue;
821
822 (void) strcat(ifnames, ifc.ifc_req[i].ifr_name);
823 (void) strcat(ifnames, " ");
824 }
825
826 if (strlen(ifnames) > 1)
827 ifnames[strlen(ifnames) - 1] = '\0';
828 }
829
830 (void) close(sock_fd);
831 free(ifc.ifc_req);
832 return (ifnames);
833 }
834
835 /*
836 * dhcp_ipc_getinfo(): attempts to retrieve a value for the specified DHCP
837 * option; tries primary interface, then all DHCP-owned
838 * interfaces, then INFORMs on the remaining interfaces
839 * (these interfaces are dropped prior to returning).
840 * input: dhcp_optnum_t *: a description of the desired option
841 * DHCP_OPT **: filled in with the (dynamically allocated) value of
842 * the option upon success.
843 * int32_t: timeout (in seconds), or DHCP_IPC_WAIT_FOREVER,
844 * or DHCP_IPC_WAIT_DEFAULT.
845 * output: int: DHCP_IPC_E_* on error, 0 upon success.
846 */
847
848 int
849 dhcp_ipc_getinfo(dhcp_optnum_t *optnum, DHCP_OPT **result, int32_t timeout)
850 {
851 dhcp_ipc_request_t *request;
852 dhcp_ipc_reply_t *reply;
853 char *ifnames, *ifnames_copy, *ifnames_head;
854 int retval;
855 time_t start_time = time(NULL);
856
857 if (timeout == DHCP_IPC_WAIT_DEFAULT)
858 timeout = DHCP_IPC_DEFAULT_WAIT;
859
860 /*
861 * wait at most 5 seconds for the agent to start.
862 */
863
864 if (dhcp_start_agent((timeout > 5 || timeout < 0) ? 5 : timeout) == -1)
865 return (DHCP_IPC_E_INT);
866
867 /*
868 * check the primary interface for the option value first.
869 */
870
871 retval = getinfo_ifnames("", optnum, result);
872 if ((retval != 0) || (retval == 0 && *result != NULL))
873 return (retval);
874
875 /*
876 * no luck. get a list of the interfaces under DHCP control
877 * and perform a GET_TAG on each one.
878 */
879
880 ifnames = get_ifnames(IFF_DHCPRUNNING, 0);
881 if (ifnames != NULL && strlen(ifnames) != 0) {
882 retval = getinfo_ifnames(ifnames, optnum, result);
883 if ((retval != 0) || (retval == 0 && *result != NULL)) {
884 free(ifnames);
885 return (retval);
886 }
887 }
888 free(ifnames);
889
890 /*
891 * still no luck. retrieve a list of all interfaces on the
892 * system that could use DHCP but aren't. send INFORMs out on
893 * each one. after that, sit in a loop for the next `timeout'
894 * seconds, trying every second to see if a response for the
895 * option we want has come in on one of the interfaces.
896 */
897
898 ifnames = get_ifnames(IFF_UP|IFF_RUNNING, IFF_LOOPBACK|IFF_DHCPRUNNING);
899 if (ifnames == NULL || strlen(ifnames) == 0) {
900 free(ifnames);
901 return (DHCP_IPC_E_NOVALUE);
902 }
903
904 ifnames_head = ifnames_copy = strdup(ifnames);
905 if (ifnames_copy == NULL) {
906 free(ifnames);
907 return (DHCP_IPC_E_MEMORY);
908 }
909
910 request = dhcp_ipc_alloc_request(DHCP_INFORM, "", NULL, 0,
911 DHCP_TYPE_NONE);
912 if (request == NULL) {
913 free(ifnames);
914 free(ifnames_head);
915 return (DHCP_IPC_E_MEMORY);
916 }
917
918 ifnames_copy = strtok(ifnames_copy, " ");
919 for (; ifnames_copy != NULL; ifnames_copy = strtok(NULL, " ")) {
920 (void) strlcpy(request->ifname, ifnames_copy, LIFNAMSIZ);
921 if (dhcp_ipc_make_request(request, &reply, 0) == 0)
922 free(reply);
923 }
924
925 for (;;) {
926 if ((timeout != DHCP_IPC_WAIT_FOREVER) &&
927 (time(NULL) - start_time > timeout)) {
928 retval = DHCP_IPC_E_TIMEOUT;
929 break;
930 }
931
932 retval = getinfo_ifnames(ifnames, optnum, result);
933 if (retval != 0 || (retval == 0 && *result != NULL))
934 break;
935
936 (void) sleep(1);
937 }
938
939 /*
940 * drop any interfaces that weren't under DHCP control before
941 * we got here; this keeps this function more of a black box
942 * and the behavior more consistent from call to call.
943 */
944
945 request->message_type = DHCP_DROP;
946
947 ifnames_copy = strcpy(ifnames_head, ifnames);
948 ifnames_copy = strtok(ifnames_copy, " ");
949 for (; ifnames_copy != NULL; ifnames_copy = strtok(NULL, " ")) {
950 (void) strlcpy(request->ifname, ifnames_copy, LIFNAMSIZ);
951 if (dhcp_ipc_make_request(request, &reply, 0) == 0)
952 free(reply);
953 }
954
955 free(request);
956 free(ifnames_head);
957 free(ifnames);
958 return (retval);
959 }
960
961 /*
962 * dhcp_ipc_timed_read(): reads from a descriptor using a maximum timeout
963 *
964 * input: int: the file descriptor to read from
965 * void *: the buffer to read into
966 * unsigned int: the total length of data to read
967 * int *: the number of milliseconds to wait; the number of
968 * milliseconds left are returned (-1 is "forever")
969 * output: int: DHCP_IPC_SUCCESS on success, DHCP_IPC_E_* otherwise
970 */
971
972 static int
973 dhcp_ipc_timed_read(int fd, void *buffer, unsigned int length, int *msec)
974 {
975 unsigned int n_total = 0;
976 ssize_t n_read;
977 struct pollfd pollfd;
978 hrtime_t start, end;
979 int retv;
980
981 pollfd.fd = fd;
982 pollfd.events = POLLIN;
983
984 while (n_total < length) {
985
986 start = gethrtime();
987
988 retv = poll(&pollfd, 1, *msec);
989 if (retv == 0) {
990 /* This can happen only if *msec is not -1 */
991 *msec = 0;
992 return (DHCP_IPC_E_TIMEOUT);
993 }
994
995 if (*msec != -1) {
996 end = gethrtime();
997 *msec -= NSEC2MSEC(end - start);
998 if (*msec < 0)
999 *msec = 0;
1000 }
1001
1002 if (retv == -1) {
1003 if (errno != EINTR)
1004 return (DHCP_IPC_E_POLL);
1005 else if (*msec == 0)
1006 return (DHCP_IPC_E_TIMEOUT);
1007 continue;
1008 }
1009
1010 if (!(pollfd.revents & POLLIN)) {
1011 errno = EINVAL;
1012 return (DHCP_IPC_E_POLL);
1013 }
1014
1015 n_read = read(fd, (caddr_t)buffer + n_total, length - n_total);
1016
1017 if (n_read == -1) {
1018 if (errno != EINTR)
1019 return (DHCP_IPC_E_READ);
1020 else if (*msec == 0)
1021 return (DHCP_IPC_E_TIMEOUT);
1022 continue;
1023 }
1024
1025 if (n_read == 0) {
1026 return (n_total == 0 ? DHCP_IPC_E_EOF :
1027 DHCP_IPC_E_PROTO);
1028 }
1029
1030 n_total += n_read;
1031
1032 if (*msec == 0 && n_total < length)
1033 return (DHCP_IPC_E_TIMEOUT);
1034 }
1035
1036 return (DHCP_IPC_SUCCESS);
1037 }