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