1 /* $NetBSD: bootp.c,v 1.14 1998/02/16 11:10:54 drochner Exp $ */ 2 3 /* 4 * Copyright (c) 1992 Regents of the University of California. 5 * All rights reserved. 6 * 7 * This software was developed by the Computer Systems Engineering group 8 * at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and 9 * contributed to Berkeley. 10 * 11 * Redistribution and use in source and binary forms, with or without 12 * modification, are permitted provided that the following conditions 13 * are met: 14 * 1. Redistributions of source code must retain the above copyright 15 * notice, this list of conditions and the following disclaimer. 16 * 2. Redistributions in binary form must reproduce the above copyright 17 * notice, this list of conditions and the following disclaimer in the 18 * documentation and/or other materials provided with the distribution. 19 * 3. Neither the name of the University nor the names of its contributors 20 * may be used to endorse or promote products derived from this software 21 * without specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 26 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33 * SUCH DAMAGE. 34 * 35 * @(#) Header: bootp.c,v 1.4 93/09/11 03:13:51 leres Exp (LBL) 36 */ 37 38 #include <sys/cdefs.h> 39 #include <stddef.h> 40 #include <sys/types.h> 41 #include <sys/limits.h> 42 #include <sys/endian.h> 43 #include <netinet/in.h> 44 #include <netinet/in_systm.h> 45 46 #include <string.h> 47 48 #define BOOTP_DEBUGxx 49 #define SUPPORT_DHCP 50 51 #define DHCP_ENV_NOVENDOR 1 /* do not parse vendor options */ 52 #define DHCP_ENV_PXE 10 /* assume pxe vendor options */ 53 #define DHCP_ENV_FREEBSD 11 /* assume freebsd vendor options */ 54 /* set DHCP_ENV to one of the values above to export dhcp options to kenv */ 55 #define DHCP_ENV DHCP_ENV_NO_VENDOR 56 57 #include "stand.h" 58 #include "net.h" 59 #include "netif.h" 60 #include "bootp.h" 61 62 63 struct in_addr servip; 64 65 static time_t bot; 66 67 static char vm_rfc1048[4] = VM_RFC1048; 68 #ifdef BOOTP_VEND_CMU 69 static char vm_cmu[4] = VM_CMU; 70 #endif 71 72 /* Local forwards */ 73 static ssize_t bootpsend(struct iodesc *, void *, size_t); 74 static ssize_t bootprecv(struct iodesc *, void **, void **, time_t, void *); 75 static int vend_rfc1048(u_char *, u_int); 76 #ifdef BOOTP_VEND_CMU 77 static void vend_cmu(u_char *); 78 #endif 79 80 #ifdef DHCP_ENV /* export the dhcp response to kenv */ 81 struct dhcp_opt; 82 static void setenv_(u_char *cp, u_char *ep, struct dhcp_opt *opts); 83 #else 84 #define setenv_(a, b, c) 85 #endif 86 87 #ifdef SUPPORT_DHCP 88 static char expected_dhcpmsgtype = -1, dhcp_ok; 89 struct in_addr dhcp_serverip; 90 #endif 91 struct bootp *bootp_response; 92 size_t bootp_response_size; 93 94 static void 95 bootp_fill_request(unsigned char *bp_vend) 96 { 97 /* 98 * We are booting from PXE, we want to send the string 99 * 'PXEClient' to the DHCP server so you have the option of 100 * only responding to PXE aware dhcp requests. 101 */ 102 bp_vend[0] = TAG_CLASSID; 103 bp_vend[1] = 9; 104 bcopy("PXEClient", &bp_vend[2], 9); 105 bp_vend[11] = TAG_USER_CLASS; 106 /* len of each user class + number of user class */ 107 bp_vend[12] = 8; 108 /* len of the first user class */ 109 bp_vend[13] = 7; 110 bcopy("FreeBSD", &bp_vend[14], 7); 111 bp_vend[21] = TAG_PARAM_REQ; 112 bp_vend[22] = 7; 113 bp_vend[23] = TAG_ROOTPATH; 114 bp_vend[24] = TAG_HOSTNAME; 115 bp_vend[25] = TAG_SWAPSERVER; 116 bp_vend[26] = TAG_GATEWAY; 117 bp_vend[27] = TAG_SUBNET_MASK; 118 bp_vend[28] = TAG_INTF_MTU; 119 bp_vend[29] = TAG_SERVERID; 120 bp_vend[30] = TAG_END; 121 } 122 123 /* Fetch required bootp infomation */ 124 void 125 bootp(int sock) 126 { 127 void *pkt; 128 struct iodesc *d; 129 struct bootp *bp; 130 struct { 131 u_char header[HEADER_SIZE]; 132 struct bootp wbootp; 133 } wbuf; 134 struct bootp *rbootp; 135 136 #ifdef BOOTP_DEBUG 137 if (debug) 138 printf("bootp: socket=%d\n", sock); 139 #endif 140 if (!bot) 141 bot = getsecs(); 142 143 if (!(d = socktodesc(sock))) { 144 printf("bootp: bad socket. %d\n", sock); 145 return; 146 } 147 #ifdef BOOTP_DEBUG 148 if (debug) 149 printf("bootp: d=%lx\n", (long)d); 150 #endif 151 152 bp = &wbuf.wbootp; 153 bzero(bp, sizeof(*bp)); 154 155 bp->bp_op = BOOTREQUEST; 156 bp->bp_htype = 1; /* 10Mb Ethernet (48 bits) */ 157 bp->bp_hlen = 6; 158 bp->bp_xid = htonl(d->xid); 159 MACPY(d->myea, bp->bp_chaddr); 160 strncpy(bp->bp_file, bootfile, sizeof(bp->bp_file)); 161 bcopy(vm_rfc1048, bp->bp_vend, sizeof(vm_rfc1048)); 162 #ifdef SUPPORT_DHCP 163 bp->bp_vend[4] = TAG_DHCP_MSGTYPE; 164 bp->bp_vend[5] = 1; 165 bp->bp_vend[6] = DHCPDISCOVER; 166 bootp_fill_request(&bp->bp_vend[7]); 167 168 #else 169 bp->bp_vend[4] = TAG_END; 170 #endif 171 172 d->myip.s_addr = INADDR_ANY; 173 d->myport = htons(IPPORT_BOOTPC); 174 d->destip.s_addr = INADDR_BROADCAST; 175 d->destport = htons(IPPORT_BOOTPS); 176 177 #ifdef SUPPORT_DHCP 178 expected_dhcpmsgtype = DHCPOFFER; 179 dhcp_ok = 0; 180 #endif 181 182 if(sendrecv(d, 183 bootpsend, bp, sizeof(*bp), 184 bootprecv, &pkt, (void **)&rbootp, NULL) == -1) { 185 printf("bootp: no reply\n"); 186 return; 187 } 188 189 #ifdef SUPPORT_DHCP 190 if(dhcp_ok) { 191 uint32_t leasetime; 192 bp->bp_vend[6] = DHCPREQUEST; 193 bp->bp_vend[7] = TAG_REQ_ADDR; 194 bp->bp_vend[8] = 4; 195 bcopy(&rbootp->bp_yiaddr, &bp->bp_vend[9], 4); 196 bp->bp_vend[13] = TAG_SERVERID; 197 bp->bp_vend[14] = 4; 198 bcopy(&dhcp_serverip.s_addr, &bp->bp_vend[15], 4); 199 bp->bp_vend[19] = TAG_LEASETIME; 200 bp->bp_vend[20] = 4; 201 leasetime = htonl(300); 202 bcopy(&leasetime, &bp->bp_vend[21], 4); 203 bootp_fill_request(&bp->bp_vend[25]); 204 205 expected_dhcpmsgtype = DHCPACK; 206 207 free(pkt); 208 if(sendrecv(d, 209 bootpsend, bp, sizeof(*bp), 210 bootprecv, &pkt, (void **)&rbootp, NULL) == -1) { 211 printf("DHCPREQUEST failed\n"); 212 return; 213 } 214 } 215 #endif 216 217 myip = d->myip = rbootp->bp_yiaddr; 218 servip = rbootp->bp_siaddr; 219 if (rootip.s_addr == INADDR_ANY) 220 rootip = servip; 221 bcopy(rbootp->bp_file, bootfile, sizeof(bootfile)); 222 bootfile[sizeof(bootfile) - 1] = '\0'; 223 224 if (!netmask) { 225 if (IN_CLASSA(ntohl(myip.s_addr))) 226 netmask = htonl(IN_CLASSA_NET); 227 else if (IN_CLASSB(ntohl(myip.s_addr))) 228 netmask = htonl(IN_CLASSB_NET); 229 else 230 netmask = htonl(IN_CLASSC_NET); 231 #ifdef BOOTP_DEBUG 232 if (debug) 233 printf("'native netmask' is %s\n", intoa(netmask)); 234 #endif 235 } 236 237 #ifdef BOOTP_DEBUG 238 if (debug) 239 printf("mask: %s\n", intoa(netmask)); 240 #endif 241 242 /* We need a gateway if root is on a different net */ 243 if (!SAMENET(myip, rootip, netmask)) { 244 #ifdef BOOTP_DEBUG 245 if (debug) 246 printf("need gateway for root ip\n"); 247 #endif 248 } 249 250 /* Toss gateway if on a different net */ 251 if (!SAMENET(myip, gateip, netmask)) { 252 #ifdef BOOTP_DEBUG 253 if (debug) 254 printf("gateway ip (%s) bad\n", inet_ntoa(gateip)); 255 #endif 256 gateip.s_addr = 0; 257 } 258 259 /* Bump xid so next request will be unique. */ 260 ++d->xid; 261 free(pkt); 262 } 263 264 /* Transmit a bootp request */ 265 static ssize_t 266 bootpsend(struct iodesc *d, void *pkt, size_t len) 267 { 268 struct bootp *bp; 269 270 #ifdef BOOTP_DEBUG 271 if (debug) 272 printf("bootpsend: d=%lx called.\n", (long)d); 273 #endif 274 275 bp = pkt; 276 bp->bp_secs = htons((u_short)(getsecs() - bot)); 277 278 #ifdef BOOTP_DEBUG 279 if (debug) 280 printf("bootpsend: calling sendudp\n"); 281 #endif 282 283 return (sendudp(d, pkt, len)); 284 } 285 286 static ssize_t 287 bootprecv(struct iodesc *d, void **pkt, void **payload, time_t tleft, 288 void *extra) 289 { 290 ssize_t n; 291 struct bootp *bp; 292 void *ptr; 293 294 #ifdef BOOTP_DEBUG 295 if (debug) 296 printf("bootp_recvoffer: called\n"); 297 #endif 298 299 ptr = NULL; 300 n = readudp(d, &ptr, (void **)&bp, tleft); 301 if (n == -1 || n < sizeof(struct bootp) - BOOTP_VENDSIZE) 302 goto bad; 303 304 #ifdef BOOTP_DEBUG 305 if (debug) 306 printf("bootprecv: checked. bp = %p, n = %zd\n", bp, n); 307 #endif 308 if (bp->bp_xid != htonl(d->xid)) { 309 #ifdef BOOTP_DEBUG 310 if (debug) { 311 printf("bootprecv: expected xid 0x%lx, got 0x%x\n", 312 d->xid, ntohl(bp->bp_xid)); 313 } 314 #endif 315 goto bad; 316 } 317 318 #ifdef BOOTP_DEBUG 319 if (debug) 320 printf("bootprecv: got one!\n"); 321 #endif 322 323 /* Suck out vendor info */ 324 if (bcmp(vm_rfc1048, bp->bp_vend, sizeof(vm_rfc1048)) == 0) { 325 int vsize = n - offsetof(struct bootp, bp_vend); 326 if (vend_rfc1048(bp->bp_vend, vsize) != 0) 327 goto bad; 328 329 /* Save copy of bootp reply or DHCP ACK message */ 330 if (bp->bp_op == BOOTREPLY && 331 ((dhcp_ok == 1 && expected_dhcpmsgtype == DHCPACK) || 332 dhcp_ok == 0)) { 333 free(bootp_response); 334 bootp_response = malloc(n); 335 if (bootp_response != NULL) { 336 bootp_response_size = n; 337 bcopy(bp, bootp_response, bootp_response_size); 338 } 339 } 340 } 341 #ifdef BOOTP_VEND_CMU 342 else if (bcmp(vm_cmu, bp->bp_vend, sizeof(vm_cmu)) == 0) 343 vend_cmu(bp->bp_vend); 344 #endif 345 else 346 printf("bootprecv: unknown vendor 0x%lx\n", (long)bp->bp_vend); 347 348 *pkt = ptr; 349 *payload = bp; 350 return (n); 351 bad: 352 free(ptr); 353 errno = 0; 354 return (-1); 355 } 356 357 static int 358 vend_rfc1048(u_char *cp, u_int len) 359 { 360 u_char *ep; 361 int size; 362 u_char tag; 363 const char *val; 364 365 #ifdef BOOTP_DEBUG 366 if (debug) 367 printf("vend_rfc1048 bootp info. len=%d\n", len); 368 #endif 369 ep = cp + len; 370 371 /* Step over magic cookie */ 372 cp += sizeof(int); 373 374 setenv_(cp, ep, NULL); 375 376 while (cp < ep) { 377 tag = *cp++; 378 size = *cp++; 379 if (tag == TAG_END) 380 break; 381 382 if (tag == TAG_SUBNET_MASK) { 383 bcopy(cp, &netmask, sizeof(netmask)); 384 } 385 if (tag == TAG_GATEWAY) { 386 bcopy(cp, &gateip.s_addr, sizeof(gateip.s_addr)); 387 } 388 if (tag == TAG_SWAPSERVER) { 389 /* let it override bp_siaddr */ 390 bcopy(cp, &rootip.s_addr, sizeof(rootip.s_addr)); 391 } 392 if (tag == TAG_ROOTPATH) { 393 if ((val = getenv("dhcp.root-path")) == NULL) 394 val = (const char *)cp; 395 strlcpy(rootpath, val, sizeof(rootpath)); 396 } 397 if (tag == TAG_HOSTNAME) { 398 if ((val = getenv("dhcp.host-name")) == NULL) 399 val = (const char *)cp; 400 strlcpy(hostname, val, sizeof(hostname)); 401 } 402 if (tag == TAG_INTF_MTU) { 403 intf_mtu = 0; 404 if ((val = getenv("dhcp.interface-mtu")) != NULL) { 405 unsigned long tmp; 406 char *end; 407 408 errno = 0; 409 /* 410 * Do not allow MTU to exceed max IPv4 packet 411 * size, max value of 16-bit word. 412 */ 413 tmp = strtoul(val, &end, 0); 414 if (errno != 0 || 415 *val == '\0' || *end != '\0' || 416 tmp > USHRT_MAX) { 417 printf("%s: bad value: \"%s\", " 418 "ignoring\n", 419 "dhcp.interface-mtu", val); 420 } else { 421 intf_mtu = (u_int)tmp; 422 } 423 } 424 if (intf_mtu <= 0) 425 intf_mtu = be16dec(cp); 426 } 427 #ifdef SUPPORT_DHCP 428 if (tag == TAG_DHCP_MSGTYPE) { 429 if(*cp != expected_dhcpmsgtype) 430 return(-1); 431 dhcp_ok = 1; 432 } 433 if (tag == TAG_SERVERID) { 434 bcopy(cp, &dhcp_serverip.s_addr, 435 sizeof(dhcp_serverip.s_addr)); 436 } 437 #endif 438 cp += size; 439 } 440 return(0); 441 } 442 443 #ifdef BOOTP_VEND_CMU 444 static void 445 vend_cmu(u_char *cp) 446 { 447 struct cmu_vend *vp; 448 449 #ifdef BOOTP_DEBUG 450 if (debug) 451 printf("vend_cmu bootp info.\n"); 452 #endif 453 vp = (struct cmu_vend *)cp; 454 455 if (vp->v_smask.s_addr != 0) { 456 netmask = vp->v_smask.s_addr; 457 } 458 if (vp->v_dgate.s_addr != 0) { 459 gateip = vp->v_dgate; 460 } 461 } 462 #endif 463 464 #ifdef DHCP_ENV 465 /* 466 * Parse DHCP options and store them into kenv variables. 467 * Original code from Danny Braniss, modifications by Luigi Rizzo. 468 * 469 * The parser is driven by tables which specify the type and name of 470 * each dhcp option and how it appears in kenv. 471 * The first entry in the list contains the prefix used to set the kenv 472 * name (including the . if needed), the last entry must have a 0 tag. 473 * Entries do not need to be sorted though it helps for readability. 474 * 475 * Certain vendor-specific tables can be enabled according to DHCP_ENV. 476 * Set it to 0 if you don't want any. 477 */ 478 enum opt_fmt { __NONE = 0, 479 __8 = 1, __16 = 2, __32 = 4, /* Unsigned fields, value=size */ 480 __IP, /* IPv4 address */ 481 __TXT, /* C string */ 482 __BYTES, /* byte sequence, printed %02x */ 483 __INDIR, /* name=value */ 484 __ILIST, /* name=value;name=value ... */ 485 __VE, /* vendor specific, recurse */ 486 }; 487 488 struct dhcp_opt { 489 uint8_t tag; 490 uint8_t fmt; 491 const char *desc; 492 }; 493 494 static struct dhcp_opt vndr_opt[] = { /* Vendor Specific Options */ 495 #if DHCP_ENV == DHCP_ENV_FREEBSD /* FreeBSD table in the original code */ 496 {0, 0, "FreeBSD"}, /* prefix */ 497 {1, __TXT, "kernel"}, 498 {2, __TXT, "kernelname"}, 499 {3, __TXT, "kernel_options"}, 500 {4, __IP, "usr-ip"}, 501 {5, __TXT, "conf-path"}, 502 {6, __TXT, "rc.conf0"}, 503 {7, __TXT, "rc.conf1"}, 504 {8, __TXT, "rc.conf2"}, 505 {9, __TXT, "rc.conf3"}, 506 {10, __TXT, "rc.conf4"}, 507 {11, __TXT, "rc.conf5"}, 508 {12, __TXT, "rc.conf6"}, 509 {13, __TXT, "rc.conf7"}, 510 {14, __TXT, "rc.conf8"}, 511 {15, __TXT, "rc.conf9"}, 512 513 {20, __TXT, "boot.nfsroot.options"}, 514 515 {245, __INDIR, ""}, 516 {246, __INDIR, ""}, 517 {247, __INDIR, ""}, 518 {248, __INDIR, ""}, 519 {249, __INDIR, ""}, 520 {250, __INDIR, ""}, 521 {251, __INDIR, ""}, 522 {252, __INDIR, ""}, 523 {253, __INDIR, ""}, 524 {254, __INDIR, ""}, 525 526 #elif DHCP_ENV == DHCP_ENV_PXE /* some pxe options, RFC4578 */ 527 {0, 0, "pxe"}, /* prefix */ 528 {93, __16, "system-architecture"}, 529 {94, __BYTES, "network-interface"}, 530 {97, __BYTES, "machine-identifier"}, 531 #else /* default (empty) table */ 532 {0, 0, "dhcp.vendor."}, /* prefix */ 533 #endif 534 {0, __TXT, "%soption-%d"} 535 }; 536 537 static struct dhcp_opt dhcp_opt[] = { 538 /* DHCP Option names, formats and codes, from RFC2132. */ 539 {0, 0, "dhcp."}, // prefix 540 {1, __IP, "subnet-mask"}, 541 {2, __32, "time-offset"}, /* this is signed */ 542 {3, __IP, "routers"}, 543 {4, __IP, "time-servers"}, 544 {5, __IP, "ien116-name-servers"}, 545 {6, __IP, "domain-name-servers"}, 546 {7, __IP, "log-servers"}, 547 {8, __IP, "cookie-servers"}, 548 {9, __IP, "lpr-servers"}, 549 {10, __IP, "impress-servers"}, 550 {11, __IP, "resource-location-servers"}, 551 {12, __TXT, "host-name"}, 552 {13, __16, "boot-size"}, 553 {14, __TXT, "merit-dump"}, 554 {15, __TXT, "domain-name"}, 555 {16, __IP, "swap-server"}, 556 {17, __TXT, "root-path"}, 557 {18, __TXT, "extensions-path"}, 558 {19, __8, "ip-forwarding"}, 559 {20, __8, "non-local-source-routing"}, 560 {21, __IP, "policy-filter"}, 561 {22, __16, "max-dgram-reassembly"}, 562 {23, __8, "default-ip-ttl"}, 563 {24, __32, "path-mtu-aging-timeout"}, 564 {25, __16, "path-mtu-plateau-table"}, 565 {26, __16, "interface-mtu"}, 566 {27, __8, "all-subnets-local"}, 567 {28, __IP, "broadcast-address"}, 568 {29, __8, "perform-mask-discovery"}, 569 {30, __8, "mask-supplier"}, 570 {31, __8, "perform-router-discovery"}, 571 {32, __IP, "router-solicitation-address"}, 572 {33, __IP, "static-routes"}, 573 {34, __8, "trailer-encapsulation"}, 574 {35, __32, "arp-cache-timeout"}, 575 {36, __8, "ieee802-3-encapsulation"}, 576 {37, __8, "default-tcp-ttl"}, 577 {38, __32, "tcp-keepalive-interval"}, 578 {39, __8, "tcp-keepalive-garbage"}, 579 {40, __TXT, "nis-domain"}, 580 {41, __IP, "nis-servers"}, 581 {42, __IP, "ntp-servers"}, 582 {43, __VE, "vendor-encapsulated-options"}, 583 {44, __IP, "netbios-name-servers"}, 584 {45, __IP, "netbios-dd-server"}, 585 {46, __8, "netbios-node-type"}, 586 {47, __TXT, "netbios-scope"}, 587 {48, __IP, "x-font-servers"}, 588 {49, __IP, "x-display-managers"}, 589 {50, __IP, "dhcp-requested-address"}, 590 {51, __32, "dhcp-lease-time"}, 591 {52, __8, "dhcp-option-overload"}, 592 {53, __8, "dhcp-message-type"}, 593 {54, __IP, "dhcp-server-identifier"}, 594 {55, __8, "dhcp-parameter-request-list"}, 595 {56, __TXT, "dhcp-message"}, 596 {57, __16, "dhcp-max-message-size"}, 597 {58, __32, "dhcp-renewal-time"}, 598 {59, __32, "dhcp-rebinding-time"}, 599 {60, __TXT, "vendor-class-identifier"}, 600 {61, __TXT, "dhcp-client-identifier"}, 601 {64, __TXT, "nisplus-domain"}, 602 {65, __IP, "nisplus-servers"}, 603 {66, __TXT, "tftp-server-name"}, 604 {67, __TXT, "bootfile-name"}, 605 {68, __IP, "mobile-ip-home-agent"}, 606 {69, __IP, "smtp-server"}, 607 {70, __IP, "pop-server"}, 608 {71, __IP, "nntp-server"}, 609 {72, __IP, "www-server"}, 610 {73, __IP, "finger-server"}, 611 {74, __IP, "irc-server"}, 612 {75, __IP, "streettalk-server"}, 613 {76, __IP, "streettalk-directory-assistance-server"}, 614 {77, __TXT, "user-class"}, 615 {85, __IP, "nds-servers"}, 616 {86, __TXT, "nds-tree-name"}, 617 {87, __TXT, "nds-context"}, 618 {210, __TXT, "authenticate"}, 619 620 /* use the following entries for arbitrary variables */ 621 {246, __ILIST, ""}, 622 {247, __ILIST, ""}, 623 {248, __ILIST, ""}, 624 {249, __ILIST, ""}, 625 {250, __INDIR, ""}, 626 {251, __INDIR, ""}, 627 {252, __INDIR, ""}, 628 {253, __INDIR, ""}, 629 {254, __INDIR, ""}, 630 {0, __TXT, "%soption-%d"} 631 }; 632 633 /* 634 * parse a dhcp response, set environment variables translating options 635 * names and values according to the tables above. Also set dhcp.tags 636 * to the list of selected tags. 637 */ 638 static void 639 setenv_(u_char *cp, u_char *ep, struct dhcp_opt *opts) 640 { 641 u_char *ncp; 642 u_char tag; 643 char tags[512], *tp; /* the list of tags */ 644 645 #define FLD_SEP ',' /* separator in list of elements */ 646 ncp = cp; 647 tp = tags; 648 if (opts == NULL) 649 opts = dhcp_opt; 650 651 while (ncp < ep) { 652 unsigned int size; /* option size */ 653 char *vp, *endv, buf[256]; /* the value buffer */ 654 struct dhcp_opt *op; 655 656 tag = *ncp++; /* extract tag and size */ 657 size = *ncp++; 658 cp = ncp; /* current payload */ 659 ncp += size; /* point to the next option */ 660 661 if (tag == TAG_END) 662 break; 663 if (tag == 0) 664 continue; 665 666 for (op = opts+1; op->tag && op->tag != tag; op++) 667 ; 668 /* if not found we end up on the default entry */ 669 670 /* 671 * Copy data into the buffer. While the code uses snprintf, it's also 672 * careful never to insert strings that would be truncated. inet_ntoa is 673 * tricky to know the size, so it assumes we can always insert it 674 * because we reserve 16 bytes at the end of the string for its worst 675 * case. Other cases are covered because they will write fewer than 676 * these reserved bytes at the end. Source strings can't overflow (as 677 * noted below) because buf is 256 bytes and all strings are limited by 678 * the protocol to be 256 bytes or smaller. 679 */ 680 vp = buf; 681 *vp = '\0'; 682 endv = buf + sizeof(buf) - 1 - 16; /* last valid write position */ 683 684 switch(op->fmt) { 685 case __NONE: 686 break; /* should not happen */ 687 688 case __VE: /* recurse, vendor specific */ 689 setenv_(cp, cp+size, vndr_opt); 690 break; 691 692 case __IP: /* ip address */ 693 for (; size > 0 && vp < endv; size -= 4, cp += 4) { 694 struct in_addr in_ip; /* ip addresses */ 695 if (vp != buf) 696 *vp++ = FLD_SEP; 697 bcopy(cp, &in_ip.s_addr, sizeof(in_ip.s_addr)); 698 snprintf(vp, endv - vp, "%s", inet_ntoa(in_ip)); 699 vp += strlen(vp); 700 } 701 break; 702 703 case __BYTES: /* opaque byte string */ 704 for (; size > 0 && vp < endv; size -= 1, cp += 1) { 705 snprintf(vp, endv - vp, "%02x", *cp); 706 vp += strlen(vp); 707 } 708 break; 709 710 case __TXT: 711 bcopy(cp, buf, size); /* cannot overflow */ 712 buf[size] = 0; 713 break; 714 715 case __32: 716 case __16: 717 case __8: /* op->fmt is also the length of each field */ 718 for (; size > 0 && vp < endv; size -= op->fmt, cp += op->fmt) { 719 uint32_t v; 720 if (op->fmt == __32) 721 v = (cp[0]<<24) + (cp[1]<<16) + (cp[2]<<8) + cp[3]; 722 else if (op->fmt == __16) 723 v = (cp[0]<<8) + cp[1]; 724 else 725 v = cp[0]; 726 if (vp != buf) 727 *vp++ = FLD_SEP; 728 snprintf(vp, endv - vp, "%u", v); 729 vp += strlen(vp); 730 } 731 break; 732 733 case __INDIR: /* name=value */ 734 case __ILIST: /* name=value;name=value... */ 735 bcopy(cp, buf, size); /* cannot overflow */ 736 buf[size] = '\0'; 737 for (endv = buf; endv; endv = vp) { 738 char *s = NULL; /* semicolon ? */ 739 740 /* skip leading whitespace */ 741 while (*endv && strchr(" \t\n\r", *endv)) 742 endv++; 743 vp = strchr(endv, '='); /* find name=value separator */ 744 if (!vp) 745 break; 746 *vp++ = 0; 747 if (op->fmt == __ILIST && (s = strchr(vp, ';'))) 748 *s++ = '\0'; 749 setenv(endv, vp, 1); 750 vp = s; /* prepare for next round */ 751 } 752 buf[0] = '\0'; /* option already done */ 753 break; 754 } 755 756 if (tp - tags < sizeof(tags) - 5) { /* add tag to the list */ 757 if (tp != tags) 758 *tp++ = FLD_SEP; 759 snprintf(tp, sizeof(tags) - (tp - tags), "%d", tag); 760 tp += strlen(tp); 761 } 762 if (buf[0]) { 763 char env[128]; /* the string name */ 764 765 if (op->tag == 0) 766 snprintf(env, sizeof(env), op->desc, opts[0].desc, tag); 767 else 768 snprintf(env, sizeof(env), "%s%s", opts[0].desc, op->desc); 769 /* 770 * Do not replace existing values in the environment, so that 771 * locally-obtained values can override server-provided values. 772 */ 773 setenv(env, buf, 0); 774 } 775 } 776 if (tp != tags) { 777 char env[128]; /* the string name */ 778 snprintf(env, sizeof(env), "%stags", opts[0].desc); 779 setenv(env, tags, 1); 780 } 781 } 782 #endif /* additional dhcp */ 783