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