1 /* 2 * Copyright (C) 2006 Michael Brown <mbrown (at) 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 } 1588
