usr/src/boot/lib/libstand/bootp.c

   1 /*
   2  * Copyright (c) 1992 Regents of the University of California.
   3  * All rights reserved.
   4  *
   5  * This software was developed by the Computer Systems Engineering group
   6  * at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and
   7  * contributed to Berkeley.
   8  *
   9  * Redistribution and use in source and binary forms, with or without
  10  * modification, are permitted provided that the following conditions
  11  * are met:
  12  * 1. Redistributions of source code must retain the above copyright
  13  *    notice, this list of conditions and the following disclaimer.
  14  * 2. Redistributions in binary form must reproduce the above copyright
  15  *    notice, this list of conditions and the following disclaimer in the
  16  *    documentation and/or other materials provided with the distribution.
  17  * 3. Neither the name of the University nor the names of its contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  */
  33
  34 #include <sys/cdefs.h>
  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
  60 struct in_addr servip;
  61
  62 static time_t   bot;
  63
  64 static  char vm_rfc1048[4] = VM_RFC1048;
  65 #ifdef BOOTP_VEND_CMU
  66 static  char vm_cmu[4] = VM_CMU;
  67 #endif
  68
  69 /* Local forwards */
  70 static  ssize_t bootpsend(struct iodesc *, void *, size_t);
  71 static  ssize_t bootprecv(struct iodesc *, void **, void **, time_t);
  72 static  int vend_rfc1048(u_char *, u_int);
  73 #ifdef BOOTP_VEND_CMU
  74 static  void vend_cmu(u_char *);
  75 #endif
  76
  77 #ifdef DHCP_ENV         /* export the dhcp response to kenv */
  78 struct dhcp_opt;
  79 static 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
  85 static char expected_dhcpmsgtype = -1, dhcp_ok;
  86 struct in_addr dhcp_serverip;
  87 #endif
  88 struct bootp *bootp_response;
  89 size_t bootp_response_size;
  90
  91 static void
  92 bootp_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("illumos", &bp_vend[14], 7);
 108         bp_vend[21] = TAG_PARAM_REQ;
 109         bp_vend[22] = 7;
 110         bp_vend[23] = TAG_SUBNET_MASK;
 111         bp_vend[24] = TAG_GATEWAY;
 112         bp_vend[25] = TAG_HOSTNAME;
 113         bp_vend[26] = TAG_SWAPSERVER;
 114         bp_vend[27] = TAG_ROOTPATH;
 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 */
 121 void
 122 bootp(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 #else
 165         bp->bp_vend[4] = TAG_END;
 166 #endif
 167
 168         d->myip.s_addr = INADDR_ANY;
 169         d->myport = htons(IPPORT_BOOTPC);
 170         d->destip.s_addr = INADDR_BROADCAST;
 171         d->destport = htons(IPPORT_BOOTPS);
 172
 173 #ifdef SUPPORT_DHCP
 174         expected_dhcpmsgtype = DHCPOFFER;
 175         dhcp_ok = 0;
 176 #endif
 177
 178         if(sendrecv(d,
 179                     bootpsend, bp, sizeof(*bp),
 180                     bootprecv, &pkt, (void **)&rbootp) == -1) {
 181             printf("bootp: no reply\n");
 182             return;
 183         }
 184
 185 #ifdef SUPPORT_DHCP
 186         if(dhcp_ok) {
 187                 u_int32_t leasetime;
 188                 bp->bp_vend[6] = DHCPREQUEST;
 189                 bp->bp_vend[7] = TAG_REQ_ADDR;
 190                 bp->bp_vend[8] = 4;
 191                 bcopy(&rbootp->bp_yiaddr, &bp->bp_vend[9], 4);
 192                 bp->bp_vend[13] = TAG_SERVERID;
 193                 bp->bp_vend[14] = 4;
 194                 bcopy(&dhcp_serverip.s_addr, &bp->bp_vend[15], 4);
 195                 bp->bp_vend[19] = TAG_LEASETIME;
 196                 bp->bp_vend[20] = 4;
 197                 leasetime = htonl(300);
 198                 bcopy(&leasetime, &bp->bp_vend[21], 4);
 199                 bootp_fill_request(&bp->bp_vend[25]);
 200
 201                 expected_dhcpmsgtype = DHCPACK;
 202
 203                 free(pkt);
 204                 if(sendrecv(d,
 205                             bootpsend, bp, sizeof(*bp),
 206                             bootprecv, &pkt, (void **)&rbootp) == -1) {
 207                         printf("DHCPREQUEST failed\n");
 208                         return;
 209                 }
 210         }
 211 #endif
 212
 213         myip = d->myip = rbootp->bp_yiaddr;
 214         servip = rbootp->bp_siaddr;
 215         if (rootip.s_addr == INADDR_ANY)
 216                 rootip = servip;
 217         bcopy(rbootp->bp_file, bootfile, sizeof(bootfile));
 218         bootfile[sizeof(bootfile) - 1] = '\0';
 219
 220         if (!netmask) {
 221                 if (IN_CLASSA(ntohl(myip.s_addr)))
 222                         netmask = htonl(IN_CLASSA_NET);
 223                 else if (IN_CLASSB(ntohl(myip.s_addr)))
 224                         netmask = htonl(IN_CLASSB_NET);
 225                 else
 226                         netmask = htonl(IN_CLASSC_NET);
 227 #ifdef BOOTP_DEBUG
 228                 if (debug)
 229                         printf("'native netmask' is %s\n", intoa(netmask));
 230 #endif
 231         }
 232
 233 #ifdef BOOTP_DEBUG
 234         if (debug)
 235                 printf("mask: %s\n", intoa(netmask));
 236 #endif
 237
 238         /* We need a gateway if root is on a different net */
 239         if (!SAMENET(myip, rootip, netmask)) {
 240 #ifdef BOOTP_DEBUG
 241                 if (debug)
 242                         printf("need gateway for root ip\n");
 243 #endif
 244         }
 245
 246         /* Toss gateway if on a different net */
 247         if (!SAMENET(myip, gateip, netmask)) {
 248 #ifdef BOOTP_DEBUG
 249                 if (debug)
 250                         printf("gateway ip (%s) bad\n", inet_ntoa(gateip));
 251 #endif
 252                 gateip.s_addr = 0;
 253         }
 254
 255         /* Bump xid so next request will be unique. */
 256         ++d->xid;
 257         free(pkt);
 258 }
 259
 260 /* Transmit a bootp request */
 261 static ssize_t
 262 bootpsend(struct iodesc *d, void *pkt, size_t len)
 263 {
 264         struct bootp *bp;
 265
 266 #ifdef BOOTP_DEBUG
 267         if (debug)
 268                 printf("bootpsend: d=%lx called.\n", (long)d);
 269 #endif
 270
 271         bp = pkt;
 272         bp->bp_secs = htons((u_short)(getsecs() - bot));
 273
 274 #ifdef BOOTP_DEBUG
 275         if (debug)
 276                 printf("bootpsend: calling sendudp\n");
 277 #endif
 278
 279         return (sendudp(d, pkt, len));
 280 }
 281
 282 static ssize_t
 283 bootprecv(struct iodesc *d, void **pkt, void **payload, time_t tleft)
 284 {
 285         ssize_t n;
 286         struct bootp *bp;
 287         void *ptr;
 288
 289 #ifdef BOOTP_DEBUG
 290         if (debug)
 291                 printf("bootp_recvoffer: called\n");
 292 #endif
 293
 294         ptr = NULL;
 295         n = readudp(d, &ptr, (void **)&bp, tleft);
 296         if (n == -1 || n < sizeof(struct bootp) - BOOTP_VENDSIZE)
 297                 goto bad;
 298
 299 #ifdef BOOTP_DEBUG
 300         if (debug)
 301                 printf("bootprecv: checked.  bp = %p, n = %zd\n", bp, n);
 302 #endif
 303         if (bp->bp_xid != htonl(d->xid)) {
 304 #ifdef BOOTP_DEBUG
 305                 if (debug) {
 306                         printf("bootprecv: expected xid 0x%lx, got 0x%x\n",
 307                             d->xid, ntohl(bp->bp_xid));
 308                 }
 309 #endif
 310                 goto bad;
 311         }
 312
 313 #ifdef BOOTP_DEBUG
 314         if (debug)
 315                 printf("bootprecv: got one!\n");
 316 #endif
 317
 318         /* Suck out vendor info */
 319         if (bcmp(vm_rfc1048, bp->bp_vend, sizeof(vm_rfc1048)) == 0) {
 320                 int vsize = n - offsetof(struct bootp, bp_vend);
 321                 if(vend_rfc1048(bp->bp_vend, vsize) != 0)
 322                     goto bad;
 323
 324                 /* Save copy of bootp reply or DHCP ACK message */
 325                 if (bp->bp_op == BOOTREPLY &&
 326                     ((dhcp_ok == 1 && expected_dhcpmsgtype == DHCPACK) ||
 327                     dhcp_ok == 0)) {
 328                         free(bootp_response);
 329                         bootp_response = malloc(n);
 330                         if (bootp_response != NULL) {
 331                                 bootp_response_size = n;
 332                                 bcopy(bp, bootp_response, bootp_response_size);
 333                         }
 334                 }
 335         }
 336 #ifdef BOOTP_VEND_CMU
 337         else if (bcmp(vm_cmu, bp->bp_vend, sizeof(vm_cmu)) == 0)
 338                 vend_cmu(bp->bp_vend);
 339 #endif
 340         else
 341                 printf("bootprecv: unknown vendor 0x%lx\n", (long)bp->bp_vend);
 342
 343         *pkt = ptr;
 344         *payload = bp;
 345         return(n);
 346 bad:
 347         free(ptr);
 348         errno = 0;
 349         return (-1);
 350 }
 351
 352 static int
 353 vend_rfc1048(u_char *cp, u_int len)
 354 {
 355         u_char *ep;
 356         int size;
 357         u_char tag;
 358         const char *val;
 359
 360 #ifdef BOOTP_DEBUG
 361         if (debug)
 362                 printf("vend_rfc1048 bootp info. len=%d\n", len);
 363 #endif
 364         ep = cp + len;
 365
 366         /* Step over magic cookie */
 367         cp += sizeof(int);
 368
 369         setenv_(cp, ep, NULL);
 370
 371         while (cp < ep) {
 372                 tag = *cp++;
 373                 size = *cp++;
 374                 if (tag == TAG_END)
 375                         break;
 376
 377                 if (tag == TAG_SUBNET_MASK) {
 378                         bcopy(cp, &netmask, sizeof(netmask));
 379                 }
 380                 if (tag == TAG_GATEWAY) {
 381                         bcopy(cp, &gateip.s_addr, sizeof(gateip.s_addr));
 382                 }
 383                 if (tag == TAG_SWAPSERVER) {
 384                         /* let it override bp_siaddr */
 385                         bcopy(cp, &rootip.s_addr, sizeof(rootip.s_addr));
 386                 }
 387                 if (tag == TAG_ROOTPATH) {
 388                         if ((val = getenv("dhcp.root-path")) == NULL)
 389                                 val = (const char *)cp;
 390                         strlcpy(rootpath, val, sizeof(rootpath));
 391                 }
 392                 if (tag == TAG_HOSTNAME) {
 393                         if ((val = getenv("dhcp.host-name")) == NULL)
 394                                 val = (const char *)cp;
 395                         strlcpy(hostname, val, sizeof(hostname));
 396                 }
 397                 if (tag == TAG_INTF_MTU) {
 398                         intf_mtu = 0;
 399                         if ((val = getenv("dhcp.interface-mtu")) != NULL) {
 400                                 unsigned long tmp;
 401                                 char *end;
 402
 403                                 errno = 0;
 404                                 /*
 405                                  * Do not allow MTU to exceed max IPv4 packet
 406                                  * size, max value of 16-bit word.
 407                                  */
 408                                 tmp = strtoul(val, &end, 0);
 409                                 if (errno != 0 ||
 410                                     *val == '\0' || *end != '\0' ||
 411                                     tmp > USHRT_MAX) {
 412                                         printf("%s: bad value: \"%s\", "
 413                                             "ignoring\n",
 414                                             "dhcp.interface-mtu", val);
 415                                 } else {
 416                                         intf_mtu = (u_int)tmp;
 417                                 }
 418                         }
 419                         if (intf_mtu == 0)
 420                                 intf_mtu = be16dec(cp);
 421                 }
 422 #ifdef SUPPORT_DHCP
 423                 if (tag == TAG_DHCP_MSGTYPE) {
 424                         if(*cp != expected_dhcpmsgtype)
 425                             return(-1);
 426                         dhcp_ok = 1;
 427                 }
 428                 if (tag == TAG_SERVERID) {
 429                         bcopy(cp, &dhcp_serverip.s_addr,
 430                               sizeof(dhcp_serverip.s_addr));
 431                 }
 432 #endif
 433                 cp += size;
 434         }
 435         return(0);
 436 }
 437
 438 #ifdef BOOTP_VEND_CMU
 439 static void
 440 vend_cmu(u_char *cp)
 441 {
 442         struct cmu_vend *vp;
 443
 444 #ifdef BOOTP_DEBUG
 445         if (debug)
 446                 printf("vend_cmu bootp info.\n");
 447 #endif
 448         vp = (struct cmu_vend *)cp;
 449
 450         if (vp->v_smask.s_addr != 0) {
 451                 netmask = vp->v_smask.s_addr;
 452         }
 453         if (vp->v_dgate.s_addr != 0) {
 454                 gateip = vp->v_dgate;
 455         }
 456 }
 457 #endif
 458
 459 #ifdef DHCP_ENV
 460 /*
 461  * Parse DHCP options and store them into kenv variables.
 462  * Original code from Danny Braniss, modifications by Luigi Rizzo.
 463  *
 464  * The parser is driven by tables which specify the type and name of
 465  * each dhcp option and how it appears in kenv.
 466  * The first entry in the list contains the prefix used to set the kenv
 467  * name (including the . if needed), the last entry must have a 0 tag.
 468  * Entries do not need to be sorted though it helps for readability.
 469  *
 470  * Certain vendor-specific tables can be enabled according to DHCP_ENV.
 471  * Set it to 0 if you don't want any.
 472  */
 473 enum opt_fmt { __NONE = 0,
 474         __8 = 1, __16 = 2, __32 = 4,    /* Unsigned fields, value=size  */
 475         __IP,                           /* IPv4 address                 */
 476         __TXT,                          /* C string                     */
 477         __BYTES,                        /* byte sequence, printed %02x  */
 478         __INDIR,                        /* name=value                   */
 479         __ILIST,                        /* name=value;name=value ... */
 480         __VE,                           /* vendor specific, recurse     */
 481 };
 482
 483 struct dhcp_opt {
 484         uint8_t tag;
 485         uint8_t fmt;
 486         const char      *desc;
 487 };
 488
 489 static struct dhcp_opt vndr_opt[] = { /* Vendor Specific Options */
 490 #if DHCP_ENV == DHCP_ENV_FREEBSD /* FreeBSD table in the original code */
 491         {0,     0,      "FreeBSD"},             /* prefix */
 492         {1,     __TXT,  "kernel"},
 493         {2,     __TXT,  "kernelname"},
 494         {3,     __TXT,  "kernel_options"},
 495         {4,     __IP,   "usr-ip"},
 496         {5,     __TXT,  "conf-path"},
 497         {6,     __TXT,  "rc.conf0"},
 498         {7,     __TXT,  "rc.conf1"},
 499         {8,     __TXT,  "rc.conf2"},
 500         {9,     __TXT,  "rc.conf3"},
 501         {10,    __TXT,  "rc.conf4"},
 502         {11,    __TXT,  "rc.conf5"},
 503         {12,    __TXT,  "rc.conf6"},
 504         {13,    __TXT,  "rc.conf7"},
 505         {14,    __TXT,  "rc.conf8"},
 506         {15,    __TXT,  "rc.conf9"},
 507
 508         {20,    __TXT,  "boot.nfsroot.options"},
 509
 510         {245,   __INDIR, ""},
 511         {246,   __INDIR, ""},
 512         {247,   __INDIR, ""},
 513         {248,   __INDIR, ""},
 514         {249,   __INDIR, ""},
 515         {250,   __INDIR, ""},
 516         {251,   __INDIR, ""},
 517         {252,   __INDIR, ""},
 518         {253,   __INDIR, ""},
 519         {254,   __INDIR, ""},
 520
 521 #elif DHCP_ENV == DHCP_ENV_PXE          /* some pxe options, RFC4578 */
 522         {0,     0,      "pxe"},         /* prefix */
 523         {93,    __16,   "system-architecture"},
 524         {94,    __BYTES,        "network-interface"},
 525         {97,    __BYTES,        "machine-identifier"},
 526 #else                                   /* default (empty) table */
 527         {0,     0,      "dhcp.vendor."},                /* prefix */
 528 #endif
 529         {0,     __TXT,  "%soption-%d"}
 530 };
 531
 532 static struct dhcp_opt dhcp_opt[] = {
 533         /* DHCP Option names, formats and codes, from RFC2132. */
 534         {0,     0,      "dhcp."},       // prefix
 535         {1,     __IP,   "subnet-mask"},
 536         {2,     __32,   "time-offset"}, /* this is signed */
 537         {3,     __IP,   "routers"},
 538         {4,     __IP,   "time-servers"},
 539         {5,     __IP,   "ien116-name-servers"},
 540         {6,     __IP,   "domain-name-servers"},
 541         {7,     __IP,   "log-servers"},
 542         {8,     __IP,   "cookie-servers"},
 543         {9,     __IP,   "lpr-servers"},
 544         {10,    __IP,   "impress-servers"},
 545         {11,    __IP,   "resource-location-servers"},
 546         {12,    __TXT,  "host-name"},
 547         {13,    __16,   "boot-size"},
 548         {14,    __TXT,  "merit-dump"},
 549         {15,    __TXT,  "domain-name"},
 550         {16,    __IP,   "swap-server"},
 551         {17,    __TXT,  "root-path"},
 552         {18,    __TXT,  "extensions-path"},
 553         {19,    __8,    "ip-forwarding"},
 554         {20,    __8,    "non-local-source-routing"},
 555         {21,    __IP,   "policy-filter"},
 556         {22,    __16,   "max-dgram-reassembly"},
 557         {23,    __8,    "default-ip-ttl"},
 558         {24,    __32,   "path-mtu-aging-timeout"},
 559         {25,    __16,   "path-mtu-plateau-table"},
 560         {26,    __16,   "interface-mtu"},
 561         {27,    __8,    "all-subnets-local"},
 562         {28,    __IP,   "broadcast-address"},
 563         {29,    __8,    "perform-mask-discovery"},
 564         {30,    __8,    "mask-supplier"},
 565         {31,    __8,    "perform-router-discovery"},
 566         {32,    __IP,   "router-solicitation-address"},
 567         {33,    __IP,   "static-routes"},
 568         {34,    __8,    "trailer-encapsulation"},
 569         {35,    __32,   "arp-cache-timeout"},
 570         {36,    __8,    "ieee802-3-encapsulation"},
 571         {37,    __8,    "default-tcp-ttl"},
 572         {38,    __32,   "tcp-keepalive-interval"},
 573         {39,    __8,    "tcp-keepalive-garbage"},
 574         {40,    __TXT,  "nis-domain"},
 575         {41,    __IP,   "nis-servers"},
 576         {42,    __IP,   "ntp-servers"},
 577         {43,    __VE,   "vendor-encapsulated-options"},
 578         {44,    __IP,   "netbios-name-servers"},
 579         {45,    __IP,   "netbios-dd-server"},
 580         {46,    __8,    "netbios-node-type"},
 581         {47,    __TXT,  "netbios-scope"},
 582         {48,    __IP,   "x-font-servers"},
 583         {49,    __IP,   "x-display-managers"},
 584         {50,    __IP,   "dhcp-requested-address"},
 585         {51,    __32,   "dhcp-lease-time"},
 586         {52,    __8,    "dhcp-option-overload"},
 587         {53,    __8,    "dhcp-message-type"},
 588         {54,    __IP,   "dhcp-server-identifier"},
 589         {55,    __8,    "dhcp-parameter-request-list"},
 590         {56,    __TXT,  "dhcp-message"},
 591         {57,    __16,   "dhcp-max-message-size"},
 592         {58,    __32,   "dhcp-renewal-time"},
 593         {59,    __32,   "dhcp-rebinding-time"},
 594         {60,    __TXT,  "vendor-class-identifier"},
 595         {61,    __TXT,  "dhcp-client-identifier"},
 596         {64,    __TXT,  "nisplus-domain"},
 597         {65,    __IP,   "nisplus-servers"},
 598         {66,    __TXT,  "tftp-server-name"},
 599         {67,    __TXT,  "bootfile-name"},
 600         {68,    __IP,   "mobile-ip-home-agent"},
 601         {69,    __IP,   "smtp-server"},
 602         {70,    __IP,   "pop-server"},
 603         {71,    __IP,   "nntp-server"},
 604         {72,    __IP,   "www-server"},
 605         {73,    __IP,   "finger-server"},
 606         {74,    __IP,   "irc-server"},
 607         {75,    __IP,   "streettalk-server"},
 608         {76,    __IP,   "streettalk-directory-assistance-server"},
 609         {77,    __TXT,  "user-class"},
 610         {85,    __IP,   "nds-servers"},
 611         {86,    __TXT,  "nds-tree-name"},
 612         {87,    __TXT,  "nds-context"},
 613         {210,   __TXT,  "authenticate"},
 614
 615         /* use the following entries for arbitrary variables */
 616         {246,   __ILIST, ""},
 617         {247,   __ILIST, ""},
 618         {248,   __ILIST, ""},
 619         {249,   __ILIST, ""},
 620         {250,   __INDIR, ""},
 621         {251,   __INDIR, ""},
 622         {252,   __INDIR, ""},
 623         {253,   __INDIR, ""},
 624         {254,   __INDIR, ""},
 625         {0,     __TXT,  "%soption-%d"}
 626 };
 627
 628 /*
 629  * parse a dhcp response, set environment variables translating options
 630  * names and values according to the tables above. Also set dhcp.tags
 631  * to the list of selected tags.
 632  */
 633 static void
 634 setenv_(u_char *cp,  u_char *ep, struct dhcp_opt *opts)
 635 {
 636     u_char      *ncp;
 637     u_char      tag;
 638     char        tags[512], *tp; /* the list of tags */
 639
 640 #define FLD_SEP ','     /* separator in list of elements */
 641     ncp = cp;
 642     tp = tags;
 643     if (opts == NULL)
 644         opts = dhcp_opt;
 645
 646     while (ncp < ep) {
 647         unsigned int    size;           /* option size */
 648         char *vp, *endv, buf[256];      /* the value buffer */
 649         struct dhcp_opt *op;
 650
 651         tag = *ncp++;                   /* extract tag and size */
 652         size = *ncp++;
 653         cp = ncp;                       /* current payload */
 654         ncp += size;                    /* point to the next option */
 655
 656         if (tag == TAG_END)
 657             break;
 658         if (tag == 0)
 659             continue;
 660
 661         for (op = opts+1; op->tag && op->tag != tag; op++)
 662                 ;
 663         /* if not found we end up on the default entry */
 664
 665         /*
 666          * Copy data into the buffer. libstand does not have snprintf so we
 667          * need to be careful with sprintf(). With strings, the source is
 668          * always <256 char so shorter than the buffer so we are safe; with
 669          * other arguments, the longest string is inet_ntoa which is 16 bytes
 670          * so we make sure to have always enough room in the string before
 671          * trying an sprint.
 672          */
 673         vp = buf;
 674         *vp = '\0';
 675         endv = buf + sizeof(buf) - 1 - 16;      /* last valid write position */
 676
 677         switch(op->fmt) {
 678         case __NONE:
 679             break;      /* should not happen */
 680
 681         case __VE: /* recurse, vendor specific */
 682             setenv_(cp, cp+size, vndr_opt);
 683             break;
 684
 685         case __IP:      /* ip address */
 686             for (; size > 0 && vp < endv; size -= 4, cp += 4) {
 687                 struct  in_addr in_ip;          /* ip addresses */
 688                 if (vp != buf)
 689                     *vp++ = FLD_SEP;
 690                 bcopy(cp, &in_ip.s_addr, sizeof(in_ip.s_addr));
 691                 sprintf(vp, "%s", inet_ntoa(in_ip));
 692                 vp += strlen(vp);
 693             }
 694             break;
 695
 696         case __BYTES:   /* opaque byte string */
 697             for (; size > 0 && vp < endv; size -= 1, cp += 1) {
 698                 sprintf(vp, "%02x", *cp);
 699                 vp += strlen(vp);
 700             }
 701             break;
 702
 703         case __TXT:
 704             bcopy(cp, buf, size);       /* cannot overflow */
 705             buf[size] = 0;
 706             break;
 707
 708         case __32:
 709         case __16:
 710         case __8:       /* op->fmt is also the length of each field */
 711             for (; size > 0 && vp < endv; size -= op->fmt, cp += op->fmt) {
 712                 uint32_t v;
 713                 if (op->fmt == __32)
 714                         v = (cp[0]<<24) + (cp[1]<<16) + (cp[2]<<8) + cp[3];
 715                 else if (op->fmt == __16)
 716                         v = (cp[0]<<8) + cp[1];
 717                 else
 718                         v = cp[0];
 719                 if (vp != buf)
 720                     *vp++ = FLD_SEP;
 721                 sprintf(vp, "%u", v);
 722                 vp += strlen(vp);
 723             }
 724             break;
 725
 726         case __INDIR:   /* name=value */
 727         case __ILIST:   /* name=value;name=value... */
 728             bcopy(cp, buf, size);       /* cannot overflow */
 729             buf[size] = '\0';
 730             for (endv = buf; endv; endv = vp) {
 731                 u_char *s = NULL;       /* semicolon ? */
 732
 733                 /* skip leading whitespace */
 734                 while (*endv && strchr(" \t\n\r", *endv))
 735                     endv++;
 736                 vp = strchr(endv, '='); /* find name=value separator */
 737                 if (!vp)
 738                     break;
 739                 *vp++ = 0;
 740                 if (op->fmt == __ILIST && (s = strchr(vp, ';')))
 741                     *s++ = '\0';
 742                 setenv(endv, vp, 1);
 743                 vp = s; /* prepare for next round */
 744             }
 745             buf[0] = '\0';      /* option already done */
 746         }
 747
 748         if (tp - tags < sizeof(tags) - 5) {     /* add tag to the list */
 749             if (tp != tags)
 750                 *tp++ = FLD_SEP;
 751             sprintf(tp, "%d", tag);
 752             tp += strlen(tp);
 753         }
 754         if (buf[0]) {
 755             char        env[128];       /* the string name */
 756
 757             if (op->tag == 0)
 758                 sprintf(env, op->desc, opts[0].desc, tag);
 759             else
 760                 sprintf(env, "%s%s", opts[0].desc, op->desc);
 761             /*
 762              * Do not replace existing values in the environment, so that
 763              * locally-obtained values can override server-provided values.
 764              */
 765             setenv(env, buf, 0);
 766         }
 767     }
 768     if (tp != tags) {
 769         char    env[128];       /* the string name */
 770         sprintf(env, "%stags", opts[0].desc);
 771         setenv(env, tags, 1);
 772     }
 773 }
 774 #endif /* additional dhcp */