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 * 4. 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__FBSDID("$FreeBSD: stable/11/stand/libsa/bootp.c 344408 2019-02-21 02:43:48Z kevans $"); 40 41#include <stddef.h> 42#include <sys/types.h> 43#include <sys/limits.h> 44#include <sys/endian.h> 45#include <netinet/in.h> 46#include <netinet/in_systm.h> 47 48#include <string.h> 49 50#define BOOTP_DEBUGxx 51#define SUPPORT_DHCP 52 53#define DHCP_ENV_NOVENDOR 1 /* do not parse vendor options */ 54#define DHCP_ENV_PXE 10 /* assume pxe vendor options */ 55#define DHCP_ENV_FREEBSD 11 /* assume freebsd vendor options */ 56/* set DHCP_ENV to one of the values above to export dhcp options to kenv */ 57#define DHCP_ENV DHCP_ENV_NO_VENDOR 58 59#include "stand.h" 60#include "net.h" 61#include "netif.h" 62#include "bootp.h" 63 64 65struct in_addr servip; 66 67static time_t bot; 68 69static char vm_rfc1048[4] = VM_RFC1048; 70#ifdef BOOTP_VEND_CMU 71static char vm_cmu[4] = VM_CMU; 72#endif 73 74/* Local forwards */ 75static ssize_t bootpsend(struct iodesc *, void *, size_t); 76static ssize_t bootprecv(struct iodesc *, void **, void **, time_t, void *); 77static int vend_rfc1048(u_char *, u_int); 78#ifdef BOOTP_VEND_CMU 79static void vend_cmu(u_char *); 80#endif 81 82#ifdef DHCP_ENV /* export the dhcp response to kenv */ 83struct dhcp_opt; 84static void setenv_(u_char *cp, u_char *ep, struct dhcp_opt *opts); 85#else 86#define setenv_(a, b, c) 87#endif 88 89#ifdef SUPPORT_DHCP 90static char expected_dhcpmsgtype = -1, dhcp_ok; 91struct in_addr dhcp_serverip; 92#endif 93struct bootp *bootp_response; 94size_t bootp_response_size; 95 96static void 97bootp_fill_request(unsigned char *bp_vend) 98{ 99 /* 100 * We are booting from PXE, we want to send the string 101 * 'PXEClient' to the DHCP server so you have the option of 102 * only responding to PXE aware dhcp requests. 103 */ 104 bp_vend[0] = TAG_CLASSID; 105 bp_vend[1] = 9; 106 bcopy("PXEClient", &bp_vend[2], 9); 107 bp_vend[11] = TAG_USER_CLASS; 108 /* len of each user class + number of user class */ 109 bp_vend[12] = 8; 110 /* len of the first user class */ 111 bp_vend[13] = 7; 112 bcopy("FreeBSD", &bp_vend[14], 7); 113 bp_vend[21] = TAG_PARAM_REQ; 114 bp_vend[22] = 7; 115 bp_vend[23] = TAG_ROOTPATH; 116 bp_vend[24] = TAG_HOSTNAME; 117 bp_vend[25] = TAG_SWAPSERVER; 118 bp_vend[26] = TAG_GATEWAY; 119 bp_vend[27] = TAG_SUBNET_MASK; 120 bp_vend[28] = TAG_INTF_MTU; 121 bp_vend[29] = TAG_SERVERID; 122 bp_vend[30] = TAG_END; 123} 124 125/* Fetch required bootp infomation */ 126void 127bootp(int sock) 128{ 129 void *pkt; 130 struct iodesc *d; 131 struct bootp *bp; 132 struct { 133 u_char header[HEADER_SIZE]; 134 struct bootp wbootp; 135 } wbuf; 136 struct bootp *rbootp; 137 138#ifdef BOOTP_DEBUG 139 if (debug) 140 printf("bootp: socket=%d\n", sock); 141#endif 142 if (!bot) 143 bot = getsecs(); 144 145 if (!(d = socktodesc(sock))) { 146 printf("bootp: bad socket. %d\n", sock); 147 return; 148 } 149#ifdef BOOTP_DEBUG 150 if (debug) 151 printf("bootp: d=%lx\n", (long)d); 152#endif 153 154 bp = &wbuf.wbootp; 155 bzero(bp, sizeof(*bp)); 156 157 bp->bp_op = BOOTREQUEST; 158 bp->bp_htype = 1; /* 10Mb Ethernet (48 bits) */ 159 bp->bp_hlen = 6; 160 bp->bp_xid = htonl(d->xid); 161 MACPY(d->myea, bp->bp_chaddr); 162 strncpy(bp->bp_file, bootfile, sizeof(bp->bp_file)); 163 bcopy(vm_rfc1048, bp->bp_vend, sizeof(vm_rfc1048)); 164#ifdef SUPPORT_DHCP 165 bp->bp_vend[4] = TAG_DHCP_MSGTYPE; 166 bp->bp_vend[5] = 1; 167 bp->bp_vend[6] = DHCPDISCOVER; 168 bootp_fill_request(&bp->bp_vend[7]); 169 170#else 171 bp->bp_vend[4] = TAG_END; 172#endif 173 174 d->myip.s_addr = INADDR_ANY; 175 d->myport = htons(IPPORT_BOOTPC); 176 d->destip.s_addr = INADDR_BROADCAST; 177 d->destport = htons(IPPORT_BOOTPS); 178 179#ifdef SUPPORT_DHCP 180 expected_dhcpmsgtype = DHCPOFFER; 181 dhcp_ok = 0; 182#endif 183 184 if(sendrecv(d, 185 bootpsend, bp, sizeof(*bp), 186 bootprecv, &pkt, (void **)&rbootp, NULL) == -1) { 187 printf("bootp: no reply\n"); 188 return; 189 } 190 191#ifdef SUPPORT_DHCP 192 if(dhcp_ok) { 193 uint32_t leasetime; 194 bp->bp_vend[6] = DHCPREQUEST; 195 bp->bp_vend[7] = TAG_REQ_ADDR; 196 bp->bp_vend[8] = 4; 197 bcopy(&rbootp->bp_yiaddr, &bp->bp_vend[9], 4); 198 bp->bp_vend[13] = TAG_SERVERID; 199 bp->bp_vend[14] = 4; 200 bcopy(&dhcp_serverip.s_addr, &bp->bp_vend[15], 4); 201 bp->bp_vend[19] = TAG_LEASETIME; 202 bp->bp_vend[20] = 4; 203 leasetime = htonl(300); 204 bcopy(&leasetime, &bp->bp_vend[21], 4); 205 bootp_fill_request(&bp->bp_vend[25]); 206 207 expected_dhcpmsgtype = DHCPACK; 208 209 free(pkt); 210 if(sendrecv(d, 211 bootpsend, bp, sizeof(*bp), 212 bootprecv, &pkt, (void **)&rbootp, NULL) == -1) { 213 printf("DHCPREQUEST failed\n"); 214 return; 215 } 216 } 217#endif 218 219 myip = d->myip = rbootp->bp_yiaddr; 220 servip = rbootp->bp_siaddr; 221 if (rootip.s_addr == INADDR_ANY) 222 rootip = servip; 223 bcopy(rbootp->bp_file, bootfile, sizeof(bootfile)); 224 bootfile[sizeof(bootfile) - 1] = '\0'; 225 226 if (!netmask) { 227 if (IN_CLASSA(ntohl(myip.s_addr))) 228 netmask = htonl(IN_CLASSA_NET); 229 else if (IN_CLASSB(ntohl(myip.s_addr))) 230 netmask = htonl(IN_CLASSB_NET); 231 else 232 netmask = htonl(IN_CLASSC_NET); 233#ifdef BOOTP_DEBUG 234 if (debug) 235 printf("'native netmask' is %s\n", intoa(netmask)); 236#endif 237 } 238 239#ifdef BOOTP_DEBUG 240 if (debug) 241 printf("mask: %s\n", intoa(netmask)); 242#endif 243 244 /* We need a gateway if root is on a different net */ 245 if (!SAMENET(myip, rootip, netmask)) { 246#ifdef BOOTP_DEBUG 247 if (debug) 248 printf("need gateway for root ip\n"); 249#endif 250 } 251 252 /* Toss gateway if on a different net */ 253 if (!SAMENET(myip, gateip, netmask)) { 254#ifdef BOOTP_DEBUG 255 if (debug) 256 printf("gateway ip (%s) bad\n", inet_ntoa(gateip)); 257#endif 258 gateip.s_addr = 0; 259 } 260 261 /* Bump xid so next request will be unique. */ 262 ++d->xid; 263 free(pkt); 264} 265 266/* Transmit a bootp request */ 267static ssize_t 268bootpsend(struct iodesc *d, void *pkt, size_t len) 269{ 270 struct bootp *bp; 271 272#ifdef BOOTP_DEBUG 273 if (debug) 274 printf("bootpsend: d=%lx called.\n", (long)d); 275#endif 276 277 bp = pkt; 278 bp->bp_secs = htons((u_short)(getsecs() - bot)); 279 280#ifdef BOOTP_DEBUG 281 if (debug) 282 printf("bootpsend: calling sendudp\n"); 283#endif 284 285 return (sendudp(d, pkt, len)); 286} 287 288static ssize_t 289bootprecv(struct iodesc *d, void **pkt, void **payload, time_t tleft, 290 void *extra) 291{ 292 ssize_t n; 293 struct bootp *bp; 294 void *ptr; 295 296#ifdef BOOTP_DEBUG 297 if (debug) 298 printf("bootp_recvoffer: called\n"); 299#endif 300 301 ptr = NULL; 302 n = readudp(d, &ptr, (void **)&bp, tleft); 303 if (n == -1 || n < sizeof(struct bootp) - BOOTP_VENDSIZE) 304 goto bad; 305 306#ifdef BOOTP_DEBUG 307 if (debug) 308 printf("bootprecv: checked. bp = %p, n = %zd\n", bp, n); 309#endif 310 if (bp->bp_xid != htonl(d->xid)) { 311#ifdef BOOTP_DEBUG 312 if (debug) { 313 printf("bootprecv: expected xid 0x%lx, got 0x%x\n", 314 d->xid, ntohl(bp->bp_xid)); 315 } 316#endif 317 goto bad; 318 } 319 320#ifdef BOOTP_DEBUG 321 if (debug) 322 printf("bootprecv: got one!\n"); 323#endif 324 325 /* Suck out vendor info */ 326 if (bcmp(vm_rfc1048, bp->bp_vend, sizeof(vm_rfc1048)) == 0) { 327 int vsize = n - offsetof(struct bootp, bp_vend); 328 if (vend_rfc1048(bp->bp_vend, vsize) != 0) 329 goto bad; 330 331 /* Save copy of bootp reply or DHCP ACK message */ 332 if (bp->bp_op == BOOTREPLY && 333 ((dhcp_ok == 1 && expected_dhcpmsgtype == DHCPACK) || 334 dhcp_ok == 0)) { 335 free(bootp_response); 336 bootp_response = malloc(n); 337 if (bootp_response != NULL) { 338 bootp_response_size = n; 339 bcopy(bp, bootp_response, bootp_response_size); 340 } 341 } 342 } 343#ifdef BOOTP_VEND_CMU 344 else if (bcmp(vm_cmu, bp->bp_vend, sizeof(vm_cmu)) == 0) 345 vend_cmu(bp->bp_vend); 346#endif 347 else 348 printf("bootprecv: unknown vendor 0x%lx\n", (long)bp->bp_vend); 349 350 *pkt = ptr; 351 *payload = bp; 352 return (n); 353bad: 354 free(ptr); 355 errno = 0; 356 return (-1); 357} 358 359static int 360vend_rfc1048(u_char *cp, u_int len) 361{ 362 u_char *ep; 363 int size; 364 u_char tag; 365 const char *val; 366 367#ifdef BOOTP_DEBUG 368 if (debug) 369 printf("vend_rfc1048 bootp info. len=%d\n", len); 370#endif 371 ep = cp + len; 372 373 /* Step over magic cookie */ 374 cp += sizeof(int); 375 376 setenv_(cp, ep, NULL); 377 378 while (cp < ep) { 379 tag = *cp++; 380 size = *cp++; 381 if (tag == TAG_END) 382 break; 383 384 if (tag == TAG_SUBNET_MASK) { 385 bcopy(cp, &netmask, sizeof(netmask)); 386 } 387 if (tag == TAG_GATEWAY) { 388 bcopy(cp, &gateip.s_addr, sizeof(gateip.s_addr)); 389 } 390 if (tag == TAG_SWAPSERVER) { 391 /* let it override bp_siaddr */ 392 bcopy(cp, &rootip.s_addr, sizeof(rootip.s_addr)); 393 } 394 if (tag == TAG_ROOTPATH) { 395 if ((val = getenv("dhcp.root-path")) == NULL) 396 val = (const char *)cp; 397 strlcpy(rootpath, val, sizeof(rootpath)); 398 } 399 if (tag == TAG_HOSTNAME) { 400 if ((val = getenv("dhcp.host-name")) == NULL) 401 val = (const char *)cp; 402 strlcpy(hostname, val, sizeof(hostname)); 403 } 404 if (tag == TAG_INTF_MTU) { 405 intf_mtu = 0; 406 if ((val = getenv("dhcp.interface-mtu")) != NULL) { 407 unsigned long tmp; 408 char *end; 409 410 errno = 0; 411 /* 412 * Do not allow MTU to exceed max IPv4 packet 413 * size, max value of 16-bit word. 414 */ 415 tmp = strtoul(val, &end, 0); 416 if (errno != 0 || 417 *val == '\0' || *end != '\0' || 418 tmp > USHRT_MAX) { 419 printf("%s: bad value: \"%s\", " 420 "ignoring\n", 421 "dhcp.interface-mtu", val); 422 } else { 423 intf_mtu = (u_int)tmp; 424 } 425 } 426 if (intf_mtu <= 0) 427 intf_mtu = be16dec(cp); 428 } 429#ifdef SUPPORT_DHCP 430 if (tag == TAG_DHCP_MSGTYPE) { 431 if(*cp != expected_dhcpmsgtype) 432 return(-1); 433 dhcp_ok = 1; 434 } 435 if (tag == TAG_SERVERID) { 436 bcopy(cp, &dhcp_serverip.s_addr, 437 sizeof(dhcp_serverip.s_addr)); 438 } 439#endif 440 cp += size; 441 } 442 return(0); 443} 444 445#ifdef BOOTP_VEND_CMU 446static void 447vend_cmu(u_char *cp) 448{ 449 struct cmu_vend *vp; 450 451#ifdef BOOTP_DEBUG 452 if (debug) 453 printf("vend_cmu bootp info.\n"); 454#endif 455 vp = (struct cmu_vend *)cp; 456 457 if (vp->v_smask.s_addr != 0) { 458 netmask = vp->v_smask.s_addr; 459 } 460 if (vp->v_dgate.s_addr != 0) { 461 gateip = vp->v_dgate; 462 } 463} 464#endif 465 466#ifdef DHCP_ENV 467/* 468 * Parse DHCP options and store them into kenv variables. 469 * Original code from Danny Braniss, modifications by Luigi Rizzo. 470 * 471 * The parser is driven by tables which specify the type and name of 472 * each dhcp option and how it appears in kenv. 473 * The first entry in the list contains the prefix used to set the kenv 474 * name (including the . if needed), the last entry must have a 0 tag. 475 * Entries do not need to be sorted though it helps for readability. 476 * 477 * Certain vendor-specific tables can be enabled according to DHCP_ENV. 478 * Set it to 0 if you don't want any. 479 */ 480enum opt_fmt { __NONE = 0, 481 __8 = 1, __16 = 2, __32 = 4, /* Unsigned fields, value=size */ 482 __IP, /* IPv4 address */ 483 __TXT, /* C string */ 484 __BYTES, /* byte sequence, printed %02x */ 485 __INDIR, /* name=value */ 486 __ILIST, /* name=value;name=value ... */ 487 __VE, /* vendor specific, recurse */ 488}; 489 490struct dhcp_opt { 491 uint8_t tag; 492 uint8_t fmt; 493 const char *desc; 494}; 495 496static struct dhcp_opt vndr_opt[] = { /* Vendor Specific Options */ 497#if DHCP_ENV == DHCP_ENV_FREEBSD /* FreeBSD table in the original code */ 498 {0, 0, "FreeBSD"}, /* prefix */ 499 {1, __TXT, "kernel"}, 500 {2, __TXT, "kernelname"}, 501 {3, __TXT, "kernel_options"}, 502 {4, __IP, "usr-ip"}, 503 {5, __TXT, "conf-path"}, 504 {6, __TXT, "rc.conf0"}, 505 {7, __TXT, "rc.conf1"}, 506 {8, __TXT, "rc.conf2"}, 507 {9, __TXT, "rc.conf3"}, 508 {10, __TXT, "rc.conf4"}, 509 {11, __TXT, "rc.conf5"}, 510 {12, __TXT, "rc.conf6"}, 511 {13, __TXT, "rc.conf7"}, 512 {14, __TXT, "rc.conf8"}, 513 {15, __TXT, "rc.conf9"}, 514 515 {20, __TXT, "boot.nfsroot.options"}, 516 517 {245, __INDIR, ""}, 518 {246, __INDIR, ""}, 519 {247, __INDIR, ""}, 520 {248, __INDIR, ""}, 521 {249, __INDIR, ""}, 522 {250, __INDIR, ""}, 523 {251, __INDIR, ""}, 524 {252, __INDIR, ""}, 525 {253, __INDIR, ""}, 526 {254, __INDIR, ""}, 527 528#elif DHCP_ENV == DHCP_ENV_PXE /* some pxe options, RFC4578 */ 529 {0, 0, "pxe"}, /* prefix */ 530 {93, __16, "system-architecture"}, 531 {94, __BYTES, "network-interface"}, 532 {97, __BYTES, "machine-identifier"}, 533#else /* default (empty) table */ 534 {0, 0, "dhcp.vendor."}, /* prefix */ 535#endif 536 {0, __TXT, "%soption-%d"} 537}; 538 539static struct dhcp_opt dhcp_opt[] = { 540 /* DHCP Option names, formats and codes, from RFC2132. */ 541 {0, 0, "dhcp."}, // prefix 542 {1, __IP, "subnet-mask"}, 543 {2, __32, "time-offset"}, /* this is signed */ 544 {3, __IP, "routers"}, 545 {4, __IP, "time-servers"}, 546 {5, __IP, "ien116-name-servers"}, 547 {6, __IP, "domain-name-servers"}, 548 {7, __IP, "log-servers"}, 549 {8, __IP, "cookie-servers"}, 550 {9, __IP, "lpr-servers"}, 551 {10, __IP, "impress-servers"}, 552 {11, __IP, "resource-location-servers"}, 553 {12, __TXT, "host-name"}, 554 {13, __16, "boot-size"}, 555 {14, __TXT, "merit-dump"}, 556 {15, __TXT, "domain-name"}, 557 {16, __IP, "swap-server"}, 558 {17, __TXT, "root-path"}, 559 {18, __TXT, "extensions-path"}, 560 {19, __8, "ip-forwarding"}, 561 {20, __8, "non-local-source-routing"}, 562 {21, __IP, "policy-filter"}, 563 {22, __16, "max-dgram-reassembly"}, 564 {23, __8, "default-ip-ttl"}, 565 {24, __32, "path-mtu-aging-timeout"}, 566 {25, __16, "path-mtu-plateau-table"}, 567 {26, __16, "interface-mtu"}, 568 {27, __8, "all-subnets-local"}, 569 {28, __IP, "broadcast-address"}, 570 {29, __8, "perform-mask-discovery"}, 571 {30, __8, "mask-supplier"}, 572 {31, __8, "perform-router-discovery"}, 573 {32, __IP, "router-solicitation-address"}, 574 {33, __IP, "static-routes"}, 575 {34, __8, "trailer-encapsulation"}, 576 {35, __32, "arp-cache-timeout"}, 577 {36, __8, "ieee802-3-encapsulation"}, 578 {37, __8, "default-tcp-ttl"}, 579 {38, __32, "tcp-keepalive-interval"}, 580 {39, __8, "tcp-keepalive-garbage"}, 581 {40, __TXT, "nis-domain"}, 582 {41, __IP, "nis-servers"}, 583 {42, __IP, "ntp-servers"}, 584 {43, __VE, "vendor-encapsulated-options"}, 585 {44, __IP, "netbios-name-servers"}, 586 {45, __IP, "netbios-dd-server"}, 587 {46, __8, "netbios-node-type"}, 588 {47, __TXT, "netbios-scope"}, 589 {48, __IP, "x-font-servers"}, 590 {49, __IP, "x-display-managers"}, 591 {50, __IP, "dhcp-requested-address"}, 592 {51, __32, "dhcp-lease-time"}, 593 {52, __8, "dhcp-option-overload"}, 594 {53, __8, "dhcp-message-type"}, 595 {54, __IP, "dhcp-server-identifier"}, 596 {55, __8, "dhcp-parameter-request-list"}, 597 {56, __TXT, "dhcp-message"}, 598 {57, __16, "dhcp-max-message-size"}, 599 {58, __32, "dhcp-renewal-time"}, 600 {59, __32, "dhcp-rebinding-time"}, 601 {60, __TXT, "vendor-class-identifier"}, 602 {61, __TXT, "dhcp-client-identifier"}, 603 {64, __TXT, "nisplus-domain"}, 604 {65, __IP, "nisplus-servers"}, 605 {66, __TXT, "tftp-server-name"}, 606 {67, __TXT, "bootfile-name"}, 607 {68, __IP, "mobile-ip-home-agent"}, 608 {69, __IP, "smtp-server"}, 609 {70, __IP, "pop-server"}, 610 {71, __IP, "nntp-server"}, 611 {72, __IP, "www-server"}, 612 {73, __IP, "finger-server"}, 613 {74, __IP, "irc-server"}, 614 {75, __IP, "streettalk-server"}, 615 {76, __IP, "streettalk-directory-assistance-server"}, 616 {77, __TXT, "user-class"}, 617 {85, __IP, "nds-servers"}, 618 {86, __TXT, "nds-tree-name"}, 619 {87, __TXT, "nds-context"}, 620 {210, __TXT, "authenticate"}, 621 622 /* use the following entries for arbitrary variables */ 623 {246, __ILIST, ""}, 624 {247, __ILIST, ""}, 625 {248, __ILIST, ""}, 626 {249, __ILIST, ""}, 627 {250, __INDIR, ""}, 628 {251, __INDIR, ""}, 629 {252, __INDIR, ""}, 630 {253, __INDIR, ""}, 631 {254, __INDIR, ""}, 632 {0, __TXT, "%soption-%d"} 633}; 634 635/* 636 * parse a dhcp response, set environment variables translating options 637 * names and values according to the tables above. Also set dhcp.tags 638 * to the list of selected tags. 639 */ 640static void 641setenv_(u_char *cp, u_char *ep, struct dhcp_opt *opts) 642{ 643 u_char *ncp; 644 u_char tag; 645 char tags[512], *tp; /* the list of tags */ 646 647#define FLD_SEP ',' /* separator in list of elements */ 648 ncp = cp; 649 tp = tags; 650 if (opts == NULL) 651 opts = dhcp_opt; 652 653 while (ncp < ep) { 654 unsigned int size; /* option size */ 655 char *vp, *endv, buf[256]; /* the value buffer */ 656 struct dhcp_opt *op; 657 658 tag = *ncp++; /* extract tag and size */ 659 size = *ncp++; 660 cp = ncp; /* current payload */ 661 ncp += size; /* point to the next option */ 662 663 if (tag == TAG_END) 664 break; 665 if (tag == 0) 666 continue; 667 668 for (op = opts+1; op->tag && op->tag != tag; op++) 669 ; 670 /* if not found we end up on the default entry */ 671 672 /* 673 * Copy data into the buffer. libstand does not have snprintf so we 674 * need to be careful with sprintf(). With strings, the source is 675 * always <256 char so shorter than the buffer so we are safe; with 676 * other arguments, the longest string is inet_ntoa which is 16 bytes 677 * so we make sure to have always enough room in the string before 678 * trying an sprint. 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 sprintf(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 sprintf(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 sprintf(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 } 754 755 if (tp - tags < sizeof(tags) - 5) { /* add tag to the list */ 756 if (tp != tags) 757 *tp++ = FLD_SEP; 758 sprintf(tp, "%d", tag); 759 tp += strlen(tp); 760 } 761 if (buf[0]) { 762 char env[128]; /* the string name */ 763 764 if (op->tag == 0) 765 sprintf(env, op->desc, opts[0].desc, tag); 766 else 767 sprintf(env, "%s%s", opts[0].desc, op->desc); 768 /* 769 * Do not replace existing values in the environment, so that 770 * locally-obtained values can override server-provided values. 771 */ 772 setenv(env, buf, 0); 773 } 774 } 775 if (tp != tags) { 776 char env[128]; /* the string name */ 777 sprintf(env, "%stags", opts[0].desc); 778 setenv(env, tags, 1); 779 } 780} 781#endif /* additional dhcp */ 782