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