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[fnrec] Add function recorder for debugging
[gpxe.git] / src / net / udp / dhcp.c
blobce2c82072ad9f84580ec174e17e8eca094770e2f
1 /*
2 * Copyright (C) 2006 Michael Brown <mbrown@fensystems.co.uk>.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License as
6 * published by the Free Software Foundation; either version 2 of the
7 * License, or any later version.
8 *
9 * This program is distributed in the hope that it will be useful, but
10 * WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
17 */
18
19 FILE_LICENCE ( GPL2_OR_LATER );
20
21 #include <string.h>
22 #include <stdlib.h>
23 #include <stdio.h>
24 #include <ctype.h>
25 #include <errno.h>
26 #include <assert.h>
27 #include <byteswap.h>
28 #include <gpxe/if_ether.h>
29 #include <gpxe/netdevice.h>
30 #include <gpxe/device.h>
31 #include <gpxe/xfer.h>
32 #include <gpxe/open.h>
33 #include <gpxe/job.h>
34 #include <gpxe/retry.h>
35 #include <gpxe/tcpip.h>
36 #include <gpxe/ip.h>
37 #include <gpxe/uuid.h>
38 #include <gpxe/timer.h>
39 #include <gpxe/settings.h>
40 #include <gpxe/dhcp.h>
41 #include <gpxe/dhcpopts.h>
42 #include <gpxe/dhcppkt.h>
43 #include <gpxe/features.h>
44
45 /** @file
46 *
47 * Dynamic Host Configuration Protocol
48 *
49 */
50
51 struct dhcp_session;
52 static int dhcp_tx ( struct dhcp_session *dhcp );
53
54 /**
55 * DHCP operation types
56 *
57 * This table maps from DHCP message types (i.e. values of the @c
58 * DHCP_MESSAGE_TYPE option) to values of the "op" field within a DHCP
59 * packet.
60 */
61 static const uint8_t dhcp_op[] = {
62 [DHCPDISCOVER] = BOOTP_REQUEST,
63 [DHCPOFFER] = BOOTP_REPLY,
64 [DHCPREQUEST] = BOOTP_REQUEST,
65 [DHCPDECLINE] = BOOTP_REQUEST,
66 [DHCPACK] = BOOTP_REPLY,
67 [DHCPNAK] = BOOTP_REPLY,
68 [DHCPRELEASE] = BOOTP_REQUEST,
69 [DHCPINFORM] = BOOTP_REQUEST,
70 };
71
72 /** Raw option data for options common to all DHCP requests */
73 static uint8_t dhcp_request_options_data[] = {
74 DHCP_MESSAGE_TYPE, DHCP_BYTE ( 0 ),
75 DHCP_MAX_MESSAGE_SIZE,
76 DHCP_WORD ( ETH_MAX_MTU - 20 /* IP header */ - 8 /* UDP header */ ),
77 DHCP_CLIENT_ARCHITECTURE, DHCP_WORD ( 0 ),
78 DHCP_CLIENT_NDI, DHCP_OPTION ( 1 /* UNDI */ , 2, 1 /* v2.1 */ ),
79 DHCP_VENDOR_CLASS_ID,
80 DHCP_STRING ( 'P', 'X', 'E', 'C', 'l', 'i', 'e', 'n', 't', ':',
81 'A', 'r', 'c', 'h', ':', '0', '0', '0', '0', '0', ':',
82 'U', 'N', 'D', 'I', ':', '0', '0', '2', '0', '0', '1' ),
83 DHCP_USER_CLASS_ID,
84 DHCP_STRING ( 'g', 'P', 'X', 'E' ),
85 DHCP_PARAMETER_REQUEST_LIST,
86 DHCP_OPTION ( DHCP_SUBNET_MASK, DHCP_ROUTERS, DHCP_DNS_SERVERS,
87 DHCP_LOG_SERVERS, DHCP_HOST_NAME, DHCP_DOMAIN_NAME,
88 DHCP_ROOT_PATH, DHCP_VENDOR_ENCAP, DHCP_VENDOR_CLASS_ID,
89 DHCP_TFTP_SERVER_NAME, DHCP_BOOTFILE_NAME,
90 DHCP_EB_ENCAP, DHCP_ISCSI_INITIATOR_IQN ),
91 DHCP_END
92 };
93
94 /** Version number feature */
95 FEATURE_VERSION ( VERSION_MAJOR, VERSION_MINOR, VERSION_PATCH );
96
97 /** DHCP server address setting */
98 struct setting dhcp_server_setting __setting = {
99 .name = "dhcp-server",
100 .description = "DHCP server address",
101 .tag = DHCP_SERVER_IDENTIFIER,
102 .type = &setting_type_ipv4,
103 };
104
105 /** DHCP user class setting */
106 struct setting user_class_setting __setting = {
107 .name = "user-class",
108 .description = "User class identifier",
109 .tag = DHCP_USER_CLASS_ID,
110 .type = &setting_type_string,
111 };
112
113 /** Use cached network settings */
114 struct setting use_cached_setting __setting = {
115 .name = "use-cached",
116 .description = "Use cached network settings",
117 .tag = DHCP_EB_USE_CACHED,
118 .type = &setting_type_uint8,
119 };
120
121 /**
122 * Name a DHCP packet type
123 *
124 * @v msgtype DHCP message type
125 * @ret string DHCP mesasge type name
126 */
127 static inline const char * dhcp_msgtype_name ( unsigned int msgtype ) {
128 switch ( msgtype ) {
129 case DHCPNONE: return "BOOTP"; /* Non-DHCP packet */
130 case DHCPDISCOVER: return "DHCPDISCOVER";
131 case DHCPOFFER: return "DHCPOFFER";
132 case DHCPREQUEST: return "DHCPREQUEST";
133 case DHCPDECLINE: return "DHCPDECLINE";
134 case DHCPACK: return "DHCPACK";
135 case DHCPNAK: return "DHCPNAK";
136 case DHCPRELEASE: return "DHCPRELEASE";
137 case DHCPINFORM: return "DHCPINFORM";
138 default: return "DHCP<invalid>";
139 }
140 }
141
142 /**
143 * Calculate DHCP transaction ID for a network device
144 *
145 * @v netdev Network device
146 * @ret xid DHCP XID
147 *
148 * Extract the least significant bits of the hardware address for use
149 * as the transaction ID.
150 */
151 static uint32_t dhcp_xid ( struct net_device *netdev ) {
152 uint32_t xid;
153
154 memcpy ( &xid, ( netdev->ll_addr + netdev->ll_protocol->ll_addr_len
155 - sizeof ( xid ) ), sizeof ( xid ) );
156 return xid;
157 }
158
159 /****************************************************************************
160 *
161 * DHCP session
162 *
163 */
164
165 struct dhcp_session;
166
167 /** DHCP session state operations */
168 struct dhcp_session_state {
169 /** State name */
170 const char *name;
171 /**
172 * Construct transmitted packet
173 *
174 * @v dhcp DHCP session
175 * @v dhcppkt DHCP packet
176 * @v peer Destination address
177 */
178 int ( * tx ) ( struct dhcp_session *dhcp,
179 struct dhcp_packet *dhcppkt,
180 struct sockaddr_in *peer );
181 /** Handle received packet
182 *
183 * @v dhcp DHCP session
184 * @v dhcppkt DHCP packet
185 * @v peer DHCP server address
186 * @v msgtype DHCP message type
187 * @v server_id DHCP server ID
188 */
189 void ( * rx ) ( struct dhcp_session *dhcp,
190 struct dhcp_packet *dhcppkt,
191 struct sockaddr_in *peer,
192 uint8_t msgtype, struct in_addr server_id );
193 /** Handle timer expiry
194 *
195 * @v dhcp DHCP session
196 */
197 void ( * expired ) ( struct dhcp_session *dhcp );
198 /** Transmitted message type */
199 uint8_t tx_msgtype;
200 /** Apply minimum timeout */
201 uint8_t apply_min_timeout;
202 };
203
204 static struct dhcp_session_state dhcp_state_discover;
205 static struct dhcp_session_state dhcp_state_request;
206 static struct dhcp_session_state dhcp_state_proxy;
207 static struct dhcp_session_state dhcp_state_pxebs;
208
209 /** DHCP offer is valid for IP lease */
210 #define DHCP_OFFER_IP 1
211
212 /** DHCP offer is valid for PXE options */
213 #define DHCP_OFFER_PXE 2
214
215 /** A DHCP offer */
216 struct dhcp_offer {
217 /** IP address of server granting offer */
218 struct in_addr server;
219
220 /** IP address being offered, or 0.0.0.0 for a pure proxy */
221 struct in_addr ip;
222
223 /** DHCP packet containing PXE options; NULL if missing or proxied */
224 struct dhcp_packet *pxe;
225
226 /** Valid uses for this offer, a combination of DHCP_OFFER bits */
227 uint8_t valid;
228
229 /** Priority of this offer */
230 int8_t priority;
231
232 /** Whether to ignore PXE DHCP extensions */
233 uint8_t no_pxedhcp;
234 };
235
236 /** Maximum number of DHCP offers to queue */
237 #define DHCP_MAX_OFFERS 6
238
239 /** A DHCP session */
240 struct dhcp_session {
241 /** Reference counter */
242 struct refcnt refcnt;
243 /** Job control interface */
244 struct job_interface job;
245 /** Data transfer interface */
246 struct xfer_interface xfer;
247
248 /** Network device being configured */
249 struct net_device *netdev;
250 /** Local socket address */
251 struct sockaddr_in local;
252 /** State of the session */
253 struct dhcp_session_state *state;
254
255 /** PXE Boot Server type */
256 uint16_t pxe_type;
257 /** List of PXE Boot Servers to attempt */
258 struct in_addr *pxe_attempt;
259 /** List of PXE Boot Servers to accept */
260 struct in_addr *pxe_accept;
261
262 /** Retransmission timer */
263 struct retry_timer timer;
264 /** Start time of the current state (in ticks) */
265 unsigned long start;
266
267 /** DHCP offer just requested */
268 struct dhcp_offer *current_offer;
269 /** List of DHCP offers received */
270 struct dhcp_offer offers[DHCP_MAX_OFFERS];
271 };
272
273 /**
274 * Free DHCP session
275 *
276 * @v refcnt Reference counter
277 */
278 static void dhcp_free ( struct refcnt *refcnt ) {
279 struct dhcp_session *dhcp =
280 container_of ( refcnt, struct dhcp_session, refcnt );
281 int i;
282
283 for ( i = 0 ; i < DHCP_MAX_OFFERS ; i++ ) {
284 if ( dhcp->offers[i].pxe )
285 dhcppkt_put ( dhcp->offers[i].pxe );
286 }
287
288 netdev_put ( dhcp->netdev );
289 free ( dhcp );
290 }
291
292 /**
293 * Mark DHCP session as complete
294 *
295 * @v dhcp DHCP session
296 * @v rc Return status code
297 */
298 static void dhcp_finished ( struct dhcp_session *dhcp, int rc ) {
299
300 /* Block futher incoming messages */
301 job_nullify ( &dhcp->job );
302 xfer_nullify ( &dhcp->xfer );
303
304 /* Stop retry timer */
305 stop_timer ( &dhcp->timer );
306
307 /* Free resources and close interfaces */
308 xfer_close ( &dhcp->xfer, rc );
309 job_done ( &dhcp->job, rc );
310 }
311
312 /**
313 * Transition to new DHCP session state
314 *
315 * @v dhcp DHCP session
316 * @v state New session state
317 */
318 static void dhcp_set_state ( struct dhcp_session *dhcp,
319 struct dhcp_session_state *state ) {
320
321 DBGC ( dhcp, "DHCP %p entering %s state\n", dhcp, state->name );
322 dhcp->state = state;
323 dhcp->start = currticks();
324 stop_timer ( &dhcp->timer );
325 dhcp->timer.min_timeout =
326 ( state->apply_min_timeout ? DHCP_MIN_TIMEOUT : 0 );
327 dhcp->timer.max_timeout = DHCP_MAX_TIMEOUT;
328 start_timer_nodelay ( &dhcp->timer );
329 }
330
331 /**
332 * Determine next DHCP offer to try
333 *
334 * @v dhcp DHCP session
335 * @v type DHCP offer type
336 * @ret offer Next DHCP offer to try
337 *
338 * Offers are ranked by priority, then by completeness (combined
339 * IP+PXE are tried before @a type alone), then by order of receipt.
340 */
341 static struct dhcp_offer * dhcp_next_offer ( struct dhcp_session *dhcp,
342 uint8_t type ) {
343
344 struct dhcp_offer *offer;
345 struct dhcp_offer *best = NULL;
346
347 for ( offer = dhcp->offers ; offer < dhcp->offers + DHCP_MAX_OFFERS ;
348 offer++ ) {
349 if ( ( offer->valid & type ) &&
350 ( ( best == NULL ) ||
351 ( offer->priority > best->priority ) ||
352 ( ( offer->priority == best->priority ) &&
353 ( offer->valid & ~best->valid ) ) ) )
354 best = offer;
355 }
356
357 return best;
358 }
359
360 /****************************************************************************
361 *
362 * DHCP state machine
363 *
364 */
365
366 /**
367 * Construct transmitted packet for DHCP discovery
368 *
369 * @v dhcp DHCP session
370 * @v dhcppkt DHCP packet
371 * @v peer Destination address
372 */
373 static int dhcp_discovery_tx ( struct dhcp_session *dhcp,
374 struct dhcp_packet *dhcppkt __unused,
375 struct sockaddr_in *peer ) {
376
377 DBGC ( dhcp, "DHCP %p DHCPDISCOVER\n", dhcp );
378
379 /* Set server address */
380 peer->sin_addr.s_addr = INADDR_BROADCAST;
381 peer->sin_port = htons ( BOOTPS_PORT );
382
383 return 0;
384 }
385
386 /**
387 * Handle received DHCPOFFER during any state
388 *
389 * @v dhcp DHCP session
390 * @v dhcppkt DHCP packet
391 * @v peer DHCP server address
392 * @v msgtype DHCP message type
393 * @v server_id DHCP server ID
394 */
395 static void dhcp_rx_offer ( struct dhcp_session *dhcp,
396 struct dhcp_packet *dhcppkt,
397 struct sockaddr_in *peer, uint8_t msgtype,
398 struct in_addr server_id ) {
399 char vci[9]; /* "PXEClient" */
400 int vci_len;
401 int has_pxeclient;
402 int pxeopts_len;
403 int has_pxeopts;
404 struct dhcp_offer *offer;
405 int i;
406
407 DBGC ( dhcp, "DHCP %p %s from %s:%d", dhcp,
408 dhcp_msgtype_name ( msgtype ), inet_ntoa ( peer->sin_addr ),
409 ntohs ( peer->sin_port ) );
410 if ( server_id.s_addr != peer->sin_addr.s_addr )
411 DBGC ( dhcp, " (%s)", inet_ntoa ( server_id ) );
412
413 /* Identify offered IP address */
414 if ( dhcppkt->dhcphdr->yiaddr.s_addr )
415 DBGC ( dhcp, " for %s", inet_ntoa ( dhcppkt->dhcphdr->yiaddr ));
416
417 /* Enqueue an offer to be filled in */
418 for ( i = 0 ; i < DHCP_MAX_OFFERS ; i++ ) {
419 if ( dhcp->offers[i].server.s_addr == server_id.s_addr ) {
420 DBGC ( dhcp, " dup\n" );
421 return;
422 }
423
424 if ( ! dhcp->offers[i].valid )
425 break;
426 }
427 if ( i == DHCP_MAX_OFFERS ) {
428 DBGC ( dhcp, " dropped\n" );
429 return;
430 }
431
432 offer = &dhcp->offers[i];
433 offer->server = server_id;
434 offer->ip = dhcppkt->dhcphdr->yiaddr;
435
436 /* Identify "PXEClient" vendor class */
437 vci_len = dhcppkt_fetch ( dhcppkt, DHCP_VENDOR_CLASS_ID,
438 vci, sizeof ( vci ) );
439 has_pxeclient = ( ( vci_len >= ( int ) sizeof ( vci ) ) &&
440 ( strncmp ( "PXEClient", vci, sizeof (vci) ) == 0 ));
441
442 /* Identify presence of PXE-specific options */
443 pxeopts_len = dhcppkt_fetch ( dhcppkt, DHCP_PXE_BOOT_MENU, NULL, 0 );
444 has_pxeopts = ( pxeopts_len >= 0 );
445 if ( has_pxeclient )
446 DBGC ( dhcp, "%s", ( has_pxeopts ? " pxe" : " proxy" ) );
447
448 if ( has_pxeclient && has_pxeopts ) {
449 /* Save reference to packet for future use */
450 if ( offer->pxe )
451 dhcppkt_put ( offer->pxe );
452 offer->pxe = dhcppkt_get ( dhcppkt );
453 }
454
455 /* Identify priority */
456 dhcppkt_fetch ( dhcppkt, DHCP_EB_PRIORITY, &offer->priority,
457 sizeof ( offer->priority ) );
458 if ( offer->priority )
459 DBGC ( dhcp, " pri %d", offer->priority );
460
461 /* Identify ignore-PXE flag */
462 dhcppkt_fetch ( dhcppkt, DHCP_EB_NO_PXEDHCP, &offer->no_pxedhcp,
463 sizeof ( offer->no_pxedhcp ) );
464 if ( offer->no_pxedhcp )
465 DBGC ( dhcp, " nopxe" );
466 DBGC ( dhcp, "\n" );
467
468 /* Determine roles this offer can fill */
469 if ( offer->ip.s_addr &&
470 ( peer->sin_port == htons ( BOOTPS_PORT ) ) &&
471 ( ( msgtype == DHCPOFFER ) || ( ! msgtype /* BOOTP */ ) ) )
472 offer->valid |= DHCP_OFFER_IP;
473
474 if ( has_pxeclient && ( msgtype == DHCPOFFER ) )
475 offer->valid |= DHCP_OFFER_PXE;
476 }
477
478 /**
479 * Handle received packet during DHCP discovery
480 *
481 * @v dhcp DHCP session
482 * @v dhcppkt DHCP packet
483 * @v peer DHCP server address
484 * @v msgtype DHCP message type
485 * @v server_id DHCP server ID
486 */
487 static void dhcp_discovery_rx ( struct dhcp_session *dhcp,
488 struct dhcp_packet *dhcppkt,
489 struct sockaddr_in *peer, uint8_t msgtype,
490 struct in_addr server_id ) {
491 unsigned long elapsed;
492 struct dhcp_offer *ip_offer;
493
494 dhcp_rx_offer ( dhcp, dhcppkt, peer, msgtype, server_id );
495
496 /* We can exit the discovery state when we have a valid
497 * DHCPOFFER, and either:
498 *
499 * o The DHCPOFFER instructs us to ignore ProxyDHCPOFFERs, or
500 * o We have a valid ProxyDHCPOFFER, or
501 * o We have allowed sufficient time for ProxyDHCPOFFERs.
502 */
503
504 /* If we don't yet have a DHCPOFFER, do nothing */
505 ip_offer = dhcp_next_offer ( dhcp, DHCP_OFFER_IP );
506 if ( ! ip_offer )
507 return;
508
509 /* If we can't yet transition to DHCPREQUEST, do nothing */
510 elapsed = ( currticks() - dhcp->start );
511 if ( ! ( ip_offer->no_pxedhcp ||
512 dhcp_next_offer ( dhcp, DHCP_OFFER_PXE ) ||
513 ( elapsed > PROXYDHCP_MAX_TIMEOUT ) ) )
514 return;
515
516 /* Transition to DHCPREQUEST */
517 dhcp_set_state ( dhcp, &dhcp_state_request );
518 }
519
520 /**
521 * Handle timer expiry during DHCP discovery
522 *
523 * @v dhcp DHCP session
524 */
525 static void dhcp_discovery_expired ( struct dhcp_session *dhcp ) {
526 unsigned long elapsed = ( currticks() - dhcp->start );
527
528 /* Give up waiting for ProxyDHCP before we reach the failure point */
529 if ( dhcp_next_offer ( dhcp, DHCP_OFFER_IP ) &&
530 ( elapsed > PROXYDHCP_MAX_TIMEOUT ) ) {
531 dhcp_set_state ( dhcp, &dhcp_state_request );
532 return;
533 }
534
535 /* Otherwise, retransmit current packet */
536 dhcp_tx ( dhcp );
537 }
538
539 /** DHCP discovery state operations */
540 static struct dhcp_session_state dhcp_state_discover = {
541 .name = "discovery",
542 .tx = dhcp_discovery_tx,
543 .rx = dhcp_discovery_rx,
544 .expired = dhcp_discovery_expired,
545 .tx_msgtype = DHCPDISCOVER,
546 .apply_min_timeout = 1,
547 };
548
549 /**
550 * Construct transmitted packet for DHCP request
551 *
552 * @v dhcp DHCP session
553 * @v dhcppkt DHCP packet
554 * @v peer Destination address
555 */
556 static int dhcp_request_tx ( struct dhcp_session *dhcp,
557 struct dhcp_packet *dhcppkt,
558 struct sockaddr_in *peer ) {
559 int rc;
560 struct dhcp_offer *offer;
561
562 offer = dhcp->current_offer = dhcp_next_offer ( dhcp, DHCP_OFFER_IP );
563
564 DBGC ( dhcp, "DHCP %p DHCPREQUEST to %s:%d",
565 dhcp, inet_ntoa ( offer->server ), BOOTPS_PORT );
566 DBGC ( dhcp, " for %s\n", inet_ntoa ( offer->ip ) );
567
568 /* Set server ID */
569 if ( ( rc = dhcppkt_store ( dhcppkt, DHCP_SERVER_IDENTIFIER,
570 &offer->server,
571 sizeof ( offer->server ) ) ) != 0 )
572 return rc;
573
574 /* Set requested IP address */
575 if ( ( rc = dhcppkt_store ( dhcppkt, DHCP_REQUESTED_ADDRESS,
576 &offer->ip, sizeof ( offer->ip ) ) ) != 0 )
577 return rc;
578
579 /* Set server address */
580 peer->sin_addr.s_addr = INADDR_BROADCAST;
581 peer->sin_port = htons ( BOOTPS_PORT );
582
583 return 0;
584 }
585
586 /**
587 * Handle received packet during DHCP request
588 *
589 * @v dhcp DHCP session
590 * @v dhcppkt DHCP packet
591 * @v peer DHCP server address
592 * @v msgtype DHCP message type
593 * @v server_id DHCP server ID
594 */
595 static void dhcp_request_rx ( struct dhcp_session *dhcp,
596 struct dhcp_packet *dhcppkt,
597 struct sockaddr_in *peer, uint8_t msgtype,
598 struct in_addr server_id ) {
599 struct in_addr ip;
600 struct settings *parent;
601 int rc;
602 struct dhcp_offer *pxe_offer;
603
604 if ( msgtype == DHCPOFFER ) {
605 dhcp_rx_offer ( dhcp, dhcppkt, peer, msgtype, server_id );
606 if ( dhcp_next_offer ( dhcp, DHCP_OFFER_IP ) !=
607 dhcp->current_offer ) {
608 /* Restart due to higher-priority offer received */
609 DBGC ( dhcp, "DHCP %p re-requesting\n", dhcp );
610 dhcp_set_state ( dhcp, &dhcp_state_request );
611 }
612 return;
613 }
614
615 DBGC ( dhcp, "DHCP %p %s from %s:%d", dhcp,
616 dhcp_msgtype_name ( msgtype ), inet_ntoa ( peer->sin_addr ),
617 ntohs ( peer->sin_port ) );
618 if ( server_id.s_addr != peer->sin_addr.s_addr )
619 DBGC ( dhcp, " (%s)", inet_ntoa ( server_id ) );
620
621 /* Identify leased IP address */
622 ip = dhcppkt->dhcphdr->yiaddr;
623 if ( ip.s_addr )
624 DBGC ( dhcp, " for %s", inet_ntoa ( ip ) );
625 DBGC ( dhcp, "\n" );
626
627 /* Filter out unacceptable responses */
628 if ( peer->sin_port != htons ( BOOTPS_PORT ) )
629 return;
630 if ( msgtype /* BOOTP */ && ( msgtype != DHCPACK ) )
631 return;
632 if ( server_id.s_addr != dhcp->current_offer->server.s_addr )
633 return;
634
635 /* Record assigned address */
636 dhcp->local.sin_addr = ip;
637
638 /* Register settings */
639 parent = netdev_settings ( dhcp->netdev );
640 if ( ( rc = register_settings ( &dhcppkt->settings, parent ) ) != 0 ){
641 DBGC ( dhcp, "DHCP %p could not register settings: %s\n",
642 dhcp, strerror ( rc ) );
643 dhcp_finished ( dhcp, rc );
644 return;
645 }
646
647 /* Locate best source of PXE settings */
648 pxe_offer = dhcp_next_offer ( dhcp, DHCP_OFFER_PXE );
649
650 if ( ( ! pxe_offer ) || /* No PXE available */
651 /* IP offer instructs us to ignore PXE */
652 dhcp->current_offer->no_pxedhcp ||
653 /* PXE settings already registered with IP offer */
654 ( ( dhcp->current_offer == pxe_offer ) && ( pxe_offer->pxe ) ) ) {
655
656 /* Terminate DHCP */
657 dhcp_finished ( dhcp, 0 );
658
659 } else if ( pxe_offer->pxe ) {
660 /* Register PXE settings and terminate DHCP */
661 pxe_offer->pxe->settings.name = PROXYDHCP_SETTINGS_NAME;
662 if ( ( rc = register_settings ( &pxe_offer->pxe->settings,
663 NULL ) ) != 0 ) {
664 DBGC ( dhcp, "DHCP %p could not register settings: "
665 "%s\n", dhcp, strerror ( rc ) );
666 }
667 dhcp_finished ( dhcp, rc );
668 } else {
669 /* Start ProxyDHCP */
670 dhcp_set_state ( dhcp, &dhcp_state_proxy );
671 }
672 }
673
674 /**
675 * Handle timer expiry during DHCP discovery
676 *
677 * @v dhcp DHCP session
678 */
679 static void dhcp_request_expired ( struct dhcp_session *dhcp ) {
680
681 /* Retransmit current packet */
682 dhcp_tx ( dhcp );
683 }
684
685 /** DHCP request state operations */
686 static struct dhcp_session_state dhcp_state_request = {
687 .name = "request",
688 .tx = dhcp_request_tx,
689 .rx = dhcp_request_rx,
690 .expired = dhcp_request_expired,
691 .tx_msgtype = DHCPREQUEST,
692 .apply_min_timeout = 0,
693 };
694
695 /**
696 * Construct transmitted packet for ProxyDHCP request
697 *
698 * @v dhcp DHCP session
699 * @v dhcppkt DHCP packet
700 * @v peer Destination address
701 */
702 static int dhcp_proxy_tx ( struct dhcp_session *dhcp,
703 struct dhcp_packet *dhcppkt,
704 struct sockaddr_in *peer ) {
705 int rc;
706 struct dhcp_offer *offer;
707
708 offer = dhcp->current_offer = dhcp_next_offer ( dhcp, DHCP_OFFER_PXE );
709
710 DBGC ( dhcp, "DHCP %p ProxyDHCP REQUEST to %s:%d\n", dhcp,
711 inet_ntoa ( offer->server ), PXE_PORT );
712
713 /* Set server ID */
714 if ( ( rc = dhcppkt_store ( dhcppkt, DHCP_SERVER_IDENTIFIER,
715 &offer->server,
716 sizeof ( offer->server ) ) ) != 0 )
717 return rc;
718
719 /* Set server address */
720 peer->sin_addr = offer->server;
721 peer->sin_port = htons ( PXE_PORT );
722
723 return 0;
724 }
725
726 /**
727 * Handle received packet during ProxyDHCP request
728 *
729 * @v dhcp DHCP session
730 * @v dhcppkt DHCP packet
731 * @v peer DHCP server address
732 * @v msgtype DHCP message type
733 * @v server_id DHCP server ID
734 */
735 static void dhcp_proxy_rx ( struct dhcp_session *dhcp,
736 struct dhcp_packet *dhcppkt,
737 struct sockaddr_in *peer, uint8_t msgtype,
738 struct in_addr server_id ) {
739 int rc;
740
741 /* Enqueue last-minute DHCPOFFERs for use in case of failure */
742 if ( peer->sin_port == htons ( BOOTPS_PORT ) &&
743 msgtype == DHCPOFFER ) {
744 dhcp_rx_offer ( dhcp, dhcppkt, peer, msgtype, server_id );
745 return;
746 }
747
748 DBGC ( dhcp, "DHCP %p %s from %s:%d", dhcp,
749 dhcp_msgtype_name ( msgtype ), inet_ntoa ( peer->sin_addr ),
750 ntohs ( peer->sin_port ) );
751 if ( server_id.s_addr != peer->sin_addr.s_addr )
752 DBGC ( dhcp, " (%s)", inet_ntoa ( server_id ) );
753 DBGC ( dhcp, "\n" );
754
755 /* Filter out unacceptable responses */
756 if ( peer->sin_port != htons ( PXE_PORT ) )
757 return;
758 if ( msgtype != DHCPACK && msgtype != DHCPOFFER )
759 return;
760 if ( server_id.s_addr /* Linux PXE server omits server ID */ &&
761 ( server_id.s_addr != dhcp->current_offer->server.s_addr ) )
762 return;
763
764 /* Register settings */
765 dhcppkt->settings.name = PROXYDHCP_SETTINGS_NAME;
766 if ( ( rc = register_settings ( &dhcppkt->settings, NULL ) ) != 0 ) {
767 DBGC ( dhcp, "DHCP %p could not register settings: %s\n",
768 dhcp, strerror ( rc ) );
769 dhcp_finished ( dhcp, rc );
770 return;
771 }
772
773 /* Terminate DHCP */
774 dhcp_finished ( dhcp, 0 );
775 }
776
777 /**
778 * Handle timer expiry during ProxyDHCP request
779 *
780 * @v dhcp DHCP session
781 */
782 static void dhcp_proxy_expired ( struct dhcp_session *dhcp ) {
783 unsigned long elapsed = ( currticks() - dhcp->start );
784
785 /* Give up waiting for ProxyDHCP before we reach the failure point */
786 if ( elapsed > PROXYDHCP_MAX_TIMEOUT ) {
787
788 /* Mark failed offer as unsuitable for ProxyDHCP */
789 dhcp->current_offer->valid &= ~DHCP_OFFER_PXE;
790
791 /* Prefer not to use only half of a PXE+IP offer if we
792 * have other offers available
793 */
794 dhcp->current_offer->priority = -1;
795
796 /* If we have any other PXE offers we can try, go back
797 * to DHCPREQUEST (since they might not be proxied
798 * offers, or might be coupled to a new IP address).
799 * We should probably DHCPRELEASE our old IP, but the
800 * standard does not require it.
801 */
802 if ( dhcp_next_offer ( dhcp, DHCP_OFFER_PXE ) ) {
803 dhcp->local.sin_addr.s_addr = 0;
804 dhcp_set_state ( dhcp, &dhcp_state_request );
805 return;
806 }
807
808 /* No possibilities left; finish without PXE options */
809 dhcp_finished ( dhcp, 0 );
810 return;
811 }
812
813 /* Retransmit current packet */
814 dhcp_tx ( dhcp );
815 }
816
817 /** ProxyDHCP request state operations */
818 static struct dhcp_session_state dhcp_state_proxy = {
819 .name = "ProxyDHCP",
820 .tx = dhcp_proxy_tx,
821 .rx = dhcp_proxy_rx,
822 .expired = dhcp_proxy_expired,
823 .tx_msgtype = DHCPREQUEST,
824 .apply_min_timeout = 0,
825 };
826
827 /**
828 * Construct transmitted packet for PXE Boot Server Discovery
829 *
830 * @v dhcp DHCP session
831 * @v dhcppkt DHCP packet
832 * @v peer Destination address
833 */
834 static int dhcp_pxebs_tx ( struct dhcp_session *dhcp,
835 struct dhcp_packet *dhcppkt,
836 struct sockaddr_in *peer ) {
837 struct dhcp_pxe_boot_menu_item menu_item = { 0, 0 };
838 int rc;
839
840 /* Set server address */
841 peer->sin_addr = *(dhcp->pxe_attempt);
842 peer->sin_port = ( ( peer->sin_addr.s_addr == INADDR_BROADCAST ) ?
843 htons ( BOOTPS_PORT ) : htons ( PXE_PORT ) );
844
845 DBGC ( dhcp, "DHCP %p PXEBS REQUEST to %s:%d for type %d\n",
846 dhcp, inet_ntoa ( peer->sin_addr ), ntohs ( peer->sin_port ),
847 le16_to_cpu ( dhcp->pxe_type ) );
848
849 /* Set boot menu item */
850 menu_item.type = dhcp->pxe_type;
851 if ( ( rc = dhcppkt_store ( dhcppkt, DHCP_PXE_BOOT_MENU_ITEM,
852 &menu_item, sizeof ( menu_item ) ) ) != 0 )
853 return rc;
854
855 return 0;
856 }
857
858 /**
859 * Check to see if PXE Boot Server address is acceptable
860 *
861 * @v dhcp DHCP session
862 * @v bs Boot Server address
863 * @ret accept Boot Server is acceptable
864 */
865 static int dhcp_pxebs_accept ( struct dhcp_session *dhcp,
866 struct in_addr bs ) {
867 struct in_addr *accept;
868
869 /* Accept if we have no acceptance filter */
870 if ( ! dhcp->pxe_accept )
871 return 1;
872
873 /* Scan through acceptance list */
874 for ( accept = dhcp->pxe_accept ; accept->s_addr ; accept++ ) {
875 if ( accept->s_addr == bs.s_addr )
876 return 1;
877 }
878
879 DBGC ( dhcp, "DHCP %p rejecting server %s\n",
880 dhcp, inet_ntoa ( bs ) );
881 return 0;
882 }
883
884 /**
885 * Handle received packet during PXE Boot Server Discovery
886 *
887 * @v dhcp DHCP session
888 * @v dhcppkt DHCP packet
889 * @v peer DHCP server address
890 * @v msgtype DHCP message type
891 * @v server_id DHCP server ID
892 */
893 static void dhcp_pxebs_rx ( struct dhcp_session *dhcp,
894 struct dhcp_packet *dhcppkt,
895 struct sockaddr_in *peer, uint8_t msgtype,
896 struct in_addr server_id ) {
897 struct dhcp_pxe_boot_menu_item menu_item = { 0, 0 };
898 int rc;
899
900 DBGC ( dhcp, "DHCP %p %s from %s:%d", dhcp,
901 dhcp_msgtype_name ( msgtype ), inet_ntoa ( peer->sin_addr ),
902 ntohs ( peer->sin_port ) );
903 if ( server_id.s_addr != peer->sin_addr.s_addr )
904 DBGC ( dhcp, " (%s)", inet_ntoa ( server_id ) );
905
906 /* Identify boot menu item */
907 dhcppkt_fetch ( dhcppkt, DHCP_PXE_BOOT_MENU_ITEM,
908 &menu_item, sizeof ( menu_item ) );
909 if ( menu_item.type )
910 DBGC ( dhcp, " for type %d", ntohs ( menu_item.type ) );
911 DBGC ( dhcp, "\n" );
912
913 /* Filter out unacceptable responses */
914 if ( ( peer->sin_port != htons ( BOOTPS_PORT ) ) &&
915 ( peer->sin_port != htons ( PXE_PORT ) ) )
916 return;
917 if ( msgtype != DHCPACK )
918 return;
919 if ( menu_item.type != dhcp->pxe_type )
920 return;
921 if ( ! dhcp_pxebs_accept ( dhcp, ( server_id.s_addr ?
922 server_id : peer->sin_addr ) ) )
923 return;
924
925 /* Register settings */
926 dhcppkt->settings.name = PXEBS_SETTINGS_NAME;
927 if ( ( rc = register_settings ( &dhcppkt->settings, NULL ) ) != 0 ) {
928 DBGC ( dhcp, "DHCP %p could not register settings: %s\n",
929 dhcp, strerror ( rc ) );
930 dhcp_finished ( dhcp, rc );
931 return;
932 }
933
934 /* Terminate DHCP */
935 dhcp_finished ( dhcp, 0 );
936 }
937
938 /**
939 * Handle timer expiry during PXE Boot Server Discovery
940 *
941 * @v dhcp DHCP session
942 */
943 static void dhcp_pxebs_expired ( struct dhcp_session *dhcp ) {
944 unsigned long elapsed = ( currticks() - dhcp->start );
945
946 /* Give up waiting before we reach the failure point, and fail
947 * over to the next server in the attempt list
948 */
949 if ( elapsed > PXEBS_MAX_TIMEOUT ) {
950 dhcp->pxe_attempt++;
951 if ( dhcp->pxe_attempt->s_addr ) {
952 dhcp_set_state ( dhcp, &dhcp_state_pxebs );
953 return;
954 } else {
955 dhcp_finished ( dhcp, -ETIMEDOUT );
956 return;
957 }
958 }
959
960 /* Retransmit current packet */
961 dhcp_tx ( dhcp );
962 }
963
964 /** PXE Boot Server Discovery state operations */
965 static struct dhcp_session_state dhcp_state_pxebs = {
966 .name = "PXEBS",
967 .tx = dhcp_pxebs_tx,
968 .rx = dhcp_pxebs_rx,
969 .expired = dhcp_pxebs_expired,
970 .tx_msgtype = DHCPREQUEST,
971 .apply_min_timeout = 1,
972 };
973
974 /****************************************************************************
975 *
976 * Packet construction
977 *
978 */
979
980 /**
981 * Construct DHCP client hardware address field and broadcast flag
982 *
983 * @v netdev Network device
984 * @v hlen DHCP hardware address length to fill in
985 * @v flags DHCP flags to fill in
986 * @ret chaddr DHCP client hardware address
987 */
988 void * dhcp_chaddr ( struct net_device *netdev, uint8_t *hlen,
989 uint16_t *flags ) {
990 struct ll_protocol *ll_protocol = netdev->ll_protocol;
991 typeof ( ( ( struct dhcphdr * ) NULL )->chaddr ) chaddr;
992
993 /* If the link-layer address cannot fit into the chaddr field
994 * (as is the case for IPoIB) then try using the hardware
995 * address instead. If we do this, set the broadcast flag,
996 * since chaddr then does not represent a valid link-layer
997 * address for the return path.
998 *
999 * If even the hardware address is too large, use an empty
1000 * chaddr field and set the broadcast flag.
1001 *
1002 * This goes against RFC4390, but RFC4390 mandates that we use
1003 * a DHCP client identifier that conforms with RFC4361, which
1004 * we cannot do without either persistent (NIC-independent)
1005 * storage, or by eliminating the hardware address completely
1006 * from the DHCP packet, which seems unfriendly to users.
1007 */
1008 if ( ( *hlen = ll_protocol->ll_addr_len ) <= sizeof ( chaddr ) ) {
1009 return netdev->ll_addr;
1010 }
1011 *flags = htons ( BOOTP_FL_BROADCAST );
1012 if ( ( *hlen = ll_protocol->hw_addr_len ) <= sizeof ( chaddr ) ) {
1013 return netdev->hw_addr;
1014 } else {
1015 *hlen = 0;
1016 return NULL;
1017 }
1018 }
1019
1020 /**
1021 * Create a DHCP packet
1022 *
1023 * @v dhcppkt DHCP packet structure to fill in
1024 * @v netdev Network device
1025 * @v msgtype DHCP message type
1026 * @v options Initial options to include (or NULL)
1027 * @v options_len Length of initial options
1028 * @v data Buffer for DHCP packet
1029 * @v max_len Size of DHCP packet buffer
1030 * @ret rc Return status code
1031 *
1032 * Creates a DHCP packet in the specified buffer, and initialise a
1033 * DHCP packet structure.
1034 */
1035 int dhcp_create_packet ( struct dhcp_packet *dhcppkt,
1036 struct net_device *netdev, uint8_t msgtype,
1037 const void *options, size_t options_len,
1038 void *data, size_t max_len ) {
1039 struct dhcphdr *dhcphdr = data;
1040 void *chaddr;
1041 int rc;
1042
1043 /* Sanity check */
1044 if ( max_len < ( sizeof ( *dhcphdr ) + options_len ) )
1045 return -ENOSPC;
1046
1047 /* Initialise DHCP packet content */
1048 memset ( dhcphdr, 0, max_len );
1049 dhcphdr->xid = dhcp_xid ( netdev );
1050 dhcphdr->magic = htonl ( DHCP_MAGIC_COOKIE );
1051 dhcphdr->htype = ntohs ( netdev->ll_protocol->ll_proto );
1052 dhcphdr->op = dhcp_op[msgtype];
1053 chaddr = dhcp_chaddr ( netdev, &dhcphdr->hlen, &dhcphdr->flags );
1054 memcpy ( dhcphdr->chaddr, chaddr, dhcphdr->hlen );
1055 memcpy ( dhcphdr->options, options, options_len );
1056
1057 /* Initialise DHCP packet structure */
1058 memset ( dhcppkt, 0, sizeof ( *dhcppkt ) );
1059 dhcppkt_init ( dhcppkt, data, max_len );
1060
1061 /* Set DHCP_MESSAGE_TYPE option */
1062 if ( ( rc = dhcppkt_store ( dhcppkt, DHCP_MESSAGE_TYPE,
1063 &msgtype, sizeof ( msgtype ) ) ) != 0 )
1064 return rc;
1065
1066 return 0;
1067 }
1068
1069 /**
1070 * Create DHCP request packet
1071 *
1072 * @v dhcppkt DHCP packet structure to fill in
1073 * @v netdev Network device
1074 * @v msgtype DHCP message type
1075 * @v ciaddr Client IP address
1076 * @v data Buffer for DHCP packet
1077 * @v max_len Size of DHCP packet buffer
1078 * @ret rc Return status code
1079 *
1080 * Creates a DHCP request packet in the specified buffer, and
1081 * initialise a DHCP packet structure.
1082 */
1083 int dhcp_create_request ( struct dhcp_packet *dhcppkt,
1084 struct net_device *netdev, unsigned int msgtype,
1085 struct in_addr ciaddr, void *data, size_t max_len ) {
1086 struct dhcp_netdev_desc dhcp_desc;
1087 struct dhcp_client_id client_id;
1088 struct dhcp_client_uuid client_uuid;
1089 uint8_t *dhcp_features;
1090 size_t dhcp_features_len;
1091 size_t ll_addr_len;
1092 ssize_t len;
1093 int rc;
1094
1095 /* Create DHCP packet */
1096 if ( ( rc = dhcp_create_packet ( dhcppkt, netdev, msgtype,
1097 dhcp_request_options_data,
1098 sizeof ( dhcp_request_options_data ),
1099 data, max_len ) ) != 0 ) {
1100 DBG ( "DHCP could not create DHCP packet: %s\n",
1101 strerror ( rc ) );
1102 return rc;
1103 }
1104
1105 /* Set client IP address */
1106 dhcppkt->dhcphdr->ciaddr = ciaddr;
1107
1108 /* Add options to identify the feature list */
1109 dhcp_features = table_start ( DHCP_FEATURES );
1110 dhcp_features_len = table_num_entries ( DHCP_FEATURES );
1111 if ( ( rc = dhcppkt_store ( dhcppkt, DHCP_EB_ENCAP, dhcp_features,
1112 dhcp_features_len ) ) != 0 ) {
1113 DBG ( "DHCP could not set features list option: %s\n",
1114 strerror ( rc ) );
1115 return rc;
1116 }
1117
1118 /* Add options to identify the network device */
1119 fetch_setting ( &netdev->settings.settings, &busid_setting, &dhcp_desc,
1120 sizeof ( dhcp_desc ) );
1121 if ( ( rc = dhcppkt_store ( dhcppkt, DHCP_EB_BUS_ID, &dhcp_desc,
1122 sizeof ( dhcp_desc ) ) ) != 0 ) {
1123 DBG ( "DHCP could not set bus ID option: %s\n",
1124 strerror ( rc ) );
1125 return rc;
1126 }
1127
1128 /* Add DHCP client identifier. Required for Infiniband, and
1129 * doesn't hurt other link layers.
1130 */
1131 client_id.ll_proto = ntohs ( netdev->ll_protocol->ll_proto );
1132 ll_addr_len = netdev->ll_protocol->ll_addr_len;
1133 assert ( ll_addr_len <= sizeof ( client_id.ll_addr ) );
1134 memcpy ( client_id.ll_addr, netdev->ll_addr, ll_addr_len );
1135 if ( ( rc = dhcppkt_store ( dhcppkt, DHCP_CLIENT_ID, &client_id,
1136 ( ll_addr_len + 1 ) ) ) != 0 ) {
1137 DBG ( "DHCP could not set client ID: %s\n",
1138 strerror ( rc ) );
1139 return rc;
1140 }
1141
1142 /* Add client UUID, if we have one. Required for PXE. */
1143 client_uuid.type = DHCP_CLIENT_UUID_TYPE;
1144 if ( ( len = fetch_uuid_setting ( NULL, &uuid_setting,
1145 &client_uuid.uuid ) ) >= 0 ) {
1146 if ( ( rc = dhcppkt_store ( dhcppkt, DHCP_CLIENT_UUID,
1147 &client_uuid,
1148 sizeof ( client_uuid ) ) ) != 0 ) {
1149 DBG ( "DHCP could not set client UUID: %s\n",
1150 strerror ( rc ) );
1151 return rc;
1152 }
1153 }
1154
1155 /* Add user class, if we have one. */
1156 if ( ( len = fetch_setting_len ( NULL, &user_class_setting ) ) >= 0 ) {
1157 char user_class[len];
1158 fetch_setting ( NULL, &user_class_setting, user_class,
1159 sizeof ( user_class ) );
1160 if ( ( rc = dhcppkt_store ( dhcppkt, DHCP_USER_CLASS_ID,
1161 &user_class,
1162 sizeof ( user_class ) ) ) != 0 ) {
1163 DBG ( "DHCP could not set user class: %s\n",
1164 strerror ( rc ) );
1165 return rc;
1166 }
1167 }
1168
1169 return 0;
1170 }
1171
1172 /****************************************************************************
1173 *
1174 * Data transfer interface
1175 *
1176 */
1177
1178 /**
1179 * Transmit DHCP request
1180 *
1181 * @v dhcp DHCP session
1182 * @ret rc Return status code
1183 */
1184 static int dhcp_tx ( struct dhcp_session *dhcp ) {
1185 static struct sockaddr_in peer = {
1186 .sin_family = AF_INET,
1187 };
1188 struct xfer_metadata meta = {
1189 .netdev = dhcp->netdev,
1190 .src = ( struct sockaddr * ) &dhcp->local,
1191 .dest = ( struct sockaddr * ) &peer,
1192 };
1193 struct io_buffer *iobuf;
1194 uint8_t msgtype = dhcp->state->tx_msgtype;
1195 struct dhcp_packet dhcppkt;
1196 int rc;
1197
1198 /* Start retry timer. Do this first so that failures to
1199 * transmit will be retried.
1200 */
1201 start_timer ( &dhcp->timer );
1202
1203 /* Allocate buffer for packet */
1204 iobuf = xfer_alloc_iob ( &dhcp->xfer, DHCP_MIN_LEN );
1205 if ( ! iobuf )
1206 return -ENOMEM;
1207
1208 /* Create basic DHCP packet in temporary buffer */
1209 if ( ( rc = dhcp_create_request ( &dhcppkt, dhcp->netdev, msgtype,
1210 dhcp->local.sin_addr, iobuf->data,
1211 iob_tailroom ( iobuf ) ) ) != 0 ) {
1212 DBGC ( dhcp, "DHCP %p could not construct DHCP request: %s\n",
1213 dhcp, strerror ( rc ) );
1214 goto done;
1215 }
1216
1217 /* Fill in packet based on current state */
1218 if ( ( rc = dhcp->state->tx ( dhcp, &dhcppkt, &peer ) ) != 0 ) {
1219 DBGC ( dhcp, "DHCP %p could not fill DHCP request: %s\n",
1220 dhcp, strerror ( rc ) );
1221 goto done;
1222 }
1223
1224 /* Transmit the packet */
1225 iob_put ( iobuf, dhcppkt.len );
1226 if ( ( rc = xfer_deliver_iob_meta ( &dhcp->xfer, iob_disown ( iobuf ),
1227 &meta ) ) != 0 ) {
1228 DBGC ( dhcp, "DHCP %p could not transmit UDP packet: %s\n",
1229 dhcp, strerror ( rc ) );
1230 goto done;
1231 }
1232
1233 done:
1234 free_iob ( iobuf );
1235 return rc;
1236 }
1237
1238 /**
1239 * Receive new data
1240 *
1241 * @v xfer Data transfer interface
1242 * @v iobuf I/O buffer
1243 * @v meta Transfer metadata
1244 * @ret rc Return status code
1245 */
1246 static int dhcp_deliver_iob ( struct xfer_interface *xfer,
1247 struct io_buffer *iobuf,
1248 struct xfer_metadata *meta ) {
1249 struct dhcp_session *dhcp =
1250 container_of ( xfer, struct dhcp_session, xfer );
1251 struct sockaddr_in *peer;
1252 size_t data_len;
1253 struct dhcp_packet *dhcppkt;
1254 struct dhcphdr *dhcphdr;
1255 uint8_t msgtype = 0;
1256 struct in_addr server_id = { 0 };
1257 int rc = 0;
1258
1259 /* Sanity checks */
1260 if ( ! meta->src ) {
1261 DBGC ( dhcp, "DHCP %p received packet without source port\n",
1262 dhcp );
1263 rc = -EINVAL;
1264 goto err_no_src;
1265 }
1266 peer = ( struct sockaddr_in * ) meta->src;
1267
1268 /* Create a DHCP packet containing the I/O buffer contents.
1269 * Whilst we could just use the original buffer in situ, that
1270 * would waste the unused space in the packet buffer, and also
1271 * waste a relatively scarce fully-aligned I/O buffer.
1272 */
1273 data_len = iob_len ( iobuf );
1274 dhcppkt = zalloc ( sizeof ( *dhcppkt ) + data_len );
1275 if ( ! dhcppkt ) {
1276 rc = -ENOMEM;
1277 goto err_alloc_dhcppkt;
1278 }
1279 dhcphdr = ( ( ( void * ) dhcppkt ) + sizeof ( *dhcppkt ) );
1280 memcpy ( dhcphdr, iobuf->data, data_len );
1281 dhcppkt_init ( dhcppkt, dhcphdr, data_len );
1282
1283 /* Identify message type */
1284 dhcppkt_fetch ( dhcppkt, DHCP_MESSAGE_TYPE, &msgtype,
1285 sizeof ( msgtype ) );
1286
1287 /* Identify server ID */
1288 dhcppkt_fetch ( dhcppkt, DHCP_SERVER_IDENTIFIER,
1289 &server_id, sizeof ( server_id ) );
1290
1291 /* Check for matching transaction ID */
1292 if ( dhcphdr->xid != dhcp_xid ( dhcp->netdev ) ) {
1293 DBGC ( dhcp, "DHCP %p %s from %s:%d has bad transaction "
1294 "ID\n", dhcp, dhcp_msgtype_name ( msgtype ),
1295 inet_ntoa ( peer->sin_addr ),
1296 ntohs ( peer->sin_port ) );
1297 rc = -EINVAL;
1298 goto err_xid;
1299 };
1300
1301 /* Handle packet based on current state */
1302 dhcp->state->rx ( dhcp, dhcppkt, peer, msgtype, server_id );
1303
1304 err_xid:
1305 dhcppkt_put ( dhcppkt );
1306 err_alloc_dhcppkt:
1307 err_no_src:
1308 free_iob ( iobuf );
1309 return rc;
1310 }
1311
1312 /** DHCP data transfer interface operations */
1313 static struct xfer_interface_operations dhcp_xfer_operations = {
1314 .close = ignore_xfer_close,
1315 .vredirect = xfer_vreopen,
1316 .window = unlimited_xfer_window,
1317 .alloc_iob = default_xfer_alloc_iob,
1318 .deliver_iob = dhcp_deliver_iob,
1319 .deliver_raw = xfer_deliver_as_iob,
1320 };
1321
1322 /**
1323 * Handle DHCP retry timer expiry
1324 *
1325 * @v timer DHCP retry timer
1326 * @v fail Failure indicator
1327 */
1328 static void dhcp_timer_expired ( struct retry_timer *timer, int fail ) {
1329 struct dhcp_session *dhcp =
1330 container_of ( timer, struct dhcp_session, timer );
1331
1332 /* If we have failed, terminate DHCP */
1333 if ( fail ) {
1334 dhcp_finished ( dhcp, -ETIMEDOUT );
1335 return;
1336 }
1337
1338 /* Handle timer expiry based on current state */
1339 dhcp->state->expired ( dhcp );
1340 }
1341
1342 /****************************************************************************
1343 *
1344 * Job control interface
1345 *
1346 */
1347
1348 /**
1349 * Handle kill() event received via job control interface
1350 *
1351 * @v job DHCP job control interface
1352 */
1353 static void dhcp_job_kill ( struct job_interface *job ) {
1354 struct dhcp_session *dhcp =
1355 container_of ( job, struct dhcp_session, job );
1356
1357 /* Terminate DHCP session */
1358 dhcp_finished ( dhcp, -ECANCELED );
1359 }
1360
1361 /** DHCP job control interface operations */
1362 static struct job_interface_operations dhcp_job_operations = {
1363 .done = ignore_job_done,
1364 .kill = dhcp_job_kill,
1365 .progress = ignore_job_progress,
1366 };
1367
1368 /****************************************************************************
1369 *
1370 * Instantiators
1371 *
1372 */
1373
1374 /**
1375 * DHCP peer address for socket opening
1376 *
1377 * This is a dummy address; the only useful portion is the socket
1378 * family (so that we get a UDP connection). The DHCP client will set
1379 * the IP address and source port explicitly on each transmission.
1380 */
1381 static struct sockaddr dhcp_peer = {
1382 .sa_family = AF_INET,
1383 };
1384
1385 /**
1386 * Start DHCP state machine on a network device
1387 *
1388 * @v job Job control interface
1389 * @v netdev Network device
1390 * @ret rc Return status code, or positive if cached
1391 *
1392 * Starts DHCP on the specified network device. If successful, the
1393 * DHCPACK (and ProxyDHCPACK, if applicable) will be registered as
1394 * option sources.
1395 *
1396 * On a return of 0, a background job has been started to perform the
1397 * DHCP request. Any nonzero return means the job has not been
1398 * started; a positive return value indicates the success condition of
1399 * having fetched the appropriate data from cached information.
1400 */
1401 int start_dhcp ( struct job_interface *job, struct net_device *netdev ) {
1402 struct dhcp_session *dhcp;
1403 int rc;
1404
1405 /* Check for cached DHCP information */
1406 get_cached_dhcpack();
1407 if ( fetch_uintz_setting ( NULL, &use_cached_setting ) ) {
1408 DBG ( "DHCP using cached network settings\n" );
1409 return 1;
1410 }
1411
1412 /* Allocate and initialise structure */
1413 dhcp = zalloc ( sizeof ( *dhcp ) );
1414 if ( ! dhcp )
1415 return -ENOMEM;
1416 dhcp->refcnt.free = dhcp_free;
1417 job_init ( &dhcp->job, &dhcp_job_operations, &dhcp->refcnt );
1418 xfer_init ( &dhcp->xfer, &dhcp_xfer_operations, &dhcp->refcnt );
1419 dhcp->netdev = netdev_get ( netdev );
1420 dhcp->local.sin_family = AF_INET;
1421 dhcp->local.sin_port = htons ( BOOTPC_PORT );
1422 dhcp->timer.expired = dhcp_timer_expired;
1423
1424 /* Instantiate child objects and attach to our interfaces */
1425 if ( ( rc = xfer_open_socket ( &dhcp->xfer, SOCK_DGRAM, &dhcp_peer,
1426 ( struct sockaddr * ) &dhcp->local ) ) != 0 )
1427 goto err;
1428
1429 /* Enter DHCPDISCOVER state */
1430 dhcp_set_state ( dhcp, &dhcp_state_discover );
1431
1432 /* Attach parent interface, mortalise self, and return */
1433 job_plug_plug ( &dhcp->job, job );
1434 ref_put ( &dhcp->refcnt );
1435 return 0;
1436
1437 err:
1438 dhcp_finished ( dhcp, rc );
1439 ref_put ( &dhcp->refcnt );
1440 return rc;
1441 }
1442
1443 /**
1444 * Retrieve list of PXE boot servers for a given server type
1445 *
1446 * @v dhcp DHCP session
1447 * @v raw DHCP PXE boot server list
1448 * @v raw_len Length of DHCP PXE boot server list
1449 * @v ip IP address list to fill in
1450 *
1451 * The caller must ensure that the IP address list has sufficient
1452 * space.
1453 */
1454 static void pxebs_list ( struct dhcp_session *dhcp, void *raw,
1455 size_t raw_len, struct in_addr *ip ) {
1456 struct dhcp_pxe_boot_server *server = raw;
1457 size_t server_len;
1458 unsigned int i;
1459
1460 while ( raw_len ) {
1461 if ( raw_len < sizeof ( *server ) ) {
1462 DBGC ( dhcp, "DHCP %p malformed PXE server list\n",
1463 dhcp );
1464 break;
1465 }
1466 server_len = offsetof ( typeof ( *server ),
1467 ip[ server->num_ip ] );
1468 if ( raw_len < server_len ) {
1469 DBGC ( dhcp, "DHCP %p malformed PXE server list\n",
1470 dhcp );
1471 break;
1472 }
1473 if ( server->type == dhcp->pxe_type ) {
1474 for ( i = 0 ; i < server->num_ip ; i++ )
1475 *(ip++) = server->ip[i];
1476 }
1477 server = ( ( ( void * ) server ) + server_len );
1478 raw_len -= server_len;
1479 }
1480 }
1481
1482 /**
1483 * Start PXE Boot Server Discovery on a network device
1484 *
1485 * @v job Job control interface
1486 * @v netdev Network device
1487 * @v pxe_type PXE server type
1488 * @ret rc Return status code
1489 *
1490 * Starts PXE Boot Server Discovery on the specified network device.
1491 * If successful, the Boot Server ACK will be registered as an option
1492 * source.
1493 */
1494 int start_pxebs ( struct job_interface *job, struct net_device *netdev,
1495 unsigned int pxe_type ) {
1496 struct setting pxe_discovery_control_setting =
1497 { .tag = DHCP_PXE_DISCOVERY_CONTROL };
1498 struct setting pxe_boot_servers_setting =
1499 { .tag = DHCP_PXE_BOOT_SERVERS };
1500 struct setting pxe_boot_server_mcast_setting =
1501 { .tag = DHCP_PXE_BOOT_SERVER_MCAST };
1502 ssize_t pxebs_list_len;
1503 struct dhcp_session *dhcp;
1504 struct in_addr *ip;
1505 unsigned int pxe_discovery_control;
1506 int rc;
1507
1508 /* Get upper bound for PXE boot server IP address list */
1509 pxebs_list_len = fetch_setting_len ( NULL, &pxe_boot_servers_setting );
1510 if ( pxebs_list_len < 0 )
1511 pxebs_list_len = 0;
1512
1513 /* Allocate and initialise structure */
1514 dhcp = zalloc ( sizeof ( *dhcp ) + sizeof ( *ip ) /* mcast */ +
1515 sizeof ( *ip ) /* bcast */ + pxebs_list_len +
1516 sizeof ( *ip ) /* terminator */ );
1517 if ( ! dhcp )
1518 return -ENOMEM;
1519 dhcp->refcnt.free = dhcp_free;
1520 job_init ( &dhcp->job, &dhcp_job_operations, &dhcp->refcnt );
1521 xfer_init ( &dhcp->xfer, &dhcp_xfer_operations, &dhcp->refcnt );
1522 dhcp->netdev = netdev_get ( netdev );
1523 dhcp->local.sin_family = AF_INET;
1524 fetch_ipv4_setting ( netdev_settings ( netdev ), &ip_setting,
1525 &dhcp->local.sin_addr );
1526 dhcp->local.sin_port = htons ( BOOTPC_PORT );
1527 dhcp->pxe_type = cpu_to_le16 ( pxe_type );
1528 dhcp->timer.expired = dhcp_timer_expired;
1529
1530 /* Construct PXE boot server IP address lists */
1531 pxe_discovery_control =
1532 fetch_uintz_setting ( NULL, &pxe_discovery_control_setting );
1533 ip = ( ( ( void * ) dhcp ) + sizeof ( *dhcp ) );
1534 dhcp->pxe_attempt = ip;
1535 if ( ! ( pxe_discovery_control & PXEBS_NO_MULTICAST ) ) {
1536 fetch_ipv4_setting ( NULL, &pxe_boot_server_mcast_setting, ip);
1537 if ( ip->s_addr )
1538 ip++;
1539 }
1540 if ( ! ( pxe_discovery_control & PXEBS_NO_BROADCAST ) )
1541 (ip++)->s_addr = INADDR_BROADCAST;
1542 if ( pxe_discovery_control & PXEBS_NO_UNKNOWN_SERVERS )
1543 dhcp->pxe_accept = ip;
1544 if ( pxebs_list_len ) {
1545 uint8_t buf[pxebs_list_len];
1546
1547 fetch_setting ( NULL, &pxe_boot_servers_setting,
1548 buf, sizeof ( buf ) );
1549 pxebs_list ( dhcp, buf, sizeof ( buf ), ip );
1550 }
1551 if ( ! dhcp->pxe_attempt->s_addr ) {
1552 DBGC ( dhcp, "DHCP %p has no PXE boot servers for type %04x\n",
1553 dhcp, pxe_type );
1554 rc = -EINVAL;
1555 goto err;
1556 }
1557
1558 /* Dump out PXE server lists */
1559 DBGC ( dhcp, "DHCP %p attempting", dhcp );
1560 for ( ip = dhcp->pxe_attempt ; ip->s_addr ; ip++ )
1561 DBGC ( dhcp, " %s", inet_ntoa ( *ip ) );
1562 DBGC ( dhcp, "\n" );
1563 if ( dhcp->pxe_accept ) {
1564 DBGC ( dhcp, "DHCP %p accepting", dhcp );
1565 for ( ip = dhcp->pxe_accept ; ip->s_addr ; ip++ )
1566 DBGC ( dhcp, " %s", inet_ntoa ( *ip ) );
1567 DBGC ( dhcp, "\n" );
1568 }
1569
1570 /* Instantiate child objects and attach to our interfaces */
1571 if ( ( rc = xfer_open_socket ( &dhcp->xfer, SOCK_DGRAM, &dhcp_peer,
1572 ( struct sockaddr * ) &dhcp->local ) ) != 0 )
1573 goto err;
1574
1575 /* Enter PXEBS state */
1576 dhcp_set_state ( dhcp, &dhcp_state_pxebs );
1577
1578 /* Attach parent interface, mortalise self, and return */
1579 job_plug_plug ( &dhcp->job, job );
1580 ref_put ( &dhcp->refcnt );
1581 return 0;
1582
1583 err:
1584 dhcp_finished ( dhcp, rc );
1585 ref_put ( &dhcp->refcnt );
1586 return rc;
1587 }
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