src/lib/dhcp.c

   1 /*
   2  * dhcp.c       Functions to send/receive dhcp packets.
   3  *
   4  * Version:     $Id$
   5  *
   6  *   This library is free software; you can redistribute it and/or
   7  *   modify it under the terms of the GNU Lesser General Public
   8  *   License as published by the Free Software Foundation; either
   9  *   version 2.1 of the License, or (at your option) any later version.
  10  *
  11  *   This library is distributed in the hope that it will be useful,
  12  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  14  *   Lesser General Public License for more details.
  15  *
  16  *   You should have received a copy of the GNU Lesser General Public
  17  *   License along with this library; if not, write to the Free Software
  18  *   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
  19  *
  20  * Copyright 2008 The FreeRADIUS server project
  21  * Copyright 2008 Alan DeKok <aland@deployingradius.com>
  22  */
  23
  24 #include        <freeradius-devel/ident.h>
  25 RCSID("$Id$")
  26
  27 #include <freeradius-devel/libradius.h>
  28 #include <freeradius-devel/udpfromto.h>
  29 #include <freeradius-devel/dhcp.h>
  30
  31 /*
  32  *      This doesn't appear to work right now.
  33  */
  34 #undef WITH_UDPFROMTO
  35
  36 #ifdef WITH_DHCP
  37
  38 #include <sys/ioctl.h>
  39
  40 #ifdef HAVE_SYS_SOCKET_H
  41 #include <sys/socket.h>
  42 #endif
  43 #ifdef HAVE_SYS_TYPES_H
  44 #include <sys/types.h>
  45 #endif
  46
  47 #include <net/if_arp.h>
  48
  49
  50 #define DHCP_CHADDR_LEN (16)
  51 #define DHCP_SNAME_LEN  (64)
  52 #define DHCP_FILE_LEN   (128)
  53 #define DHCP_VEND_LEN   (308)
  54 #define DHCP_OPTION_MAGIC_NUMBER (0x63825363)
  55
  56 #ifndef INADDR_BROADCAST
  57 #define INADDR_BROADCAST INADDR_NONE
  58 #endif
  59
  60 typedef struct dhcp_packet_t {
  61         uint8_t         opcode;
  62         uint8_t         htype;
  63         uint8_t         hlen;
  64         uint8_t         hops;
  65         uint32_t        xid;    /* 4 */
  66         uint16_t        secs;   /* 8 */
  67         uint16_t        flags;
  68         uint32_t        ciaddr; /* 12 */
  69         uint32_t        yiaddr; /* 16 */
  70         uint32_t        siaddr; /* 20 */
  71         uint32_t        giaddr; /* 24 */
  72         uint8_t         chaddr[DHCP_CHADDR_LEN]; /* 28 */
  73         uint8_t         sname[DHCP_SNAME_LEN]; /* 44 */
  74         uint8_t         file[DHCP_FILE_LEN]; /* 108 */
  75         uint32_t        option_format; /* 236 */
  76         uint8_t         options[DHCP_VEND_LEN];
  77 } dhcp_packet_t;
  78
  79 typedef struct dhcp_option_t {
  80         uint8_t         code;
  81         uint8_t         length;
  82 } dhcp_option_t;
  83
  84 /*
  85  *      INADDR_ANY : 68 -> INADDR_BROADCAST : 67        DISCOVER
  86  *      INADDR_BROADCAST : 68 <- SERVER_IP : 67         OFFER
  87  *      INADDR_ANY : 68 -> INADDR_BROADCAST : 67        REQUEST
  88  *      INADDR_BROADCAST : 68 <- SERVER_IP : 67         ACK
  89  */
  90 static const char *dhcp_header_names[] = {
  91         "DHCP-Opcode",
  92         "DHCP-Hardware-Type",
  93         "DHCP-Hardware-Address-Length",
  94         "DHCP-Hop-Count",
  95         "DHCP-Transaction-Id",
  96         "DHCP-Number-of-Seconds",
  97         "DHCP-Flags",
  98         "DHCP-Client-IP-Address",
  99         "DHCP-Your-IP-Address",
 100         "DHCP-Server-IP-Address",
 101         "DHCP-Gateway-IP-Address",
 102         "DHCP-Client-Hardware-Address",
 103         "DHCP-Server-Host-Name",
 104         "DHCP-Boot-Filename",
 105
 106         NULL
 107 };
 108
 109 static const char *dhcp_message_types[] = {
 110         "invalid",
 111         "DHCP-Discover",
 112         "DHCP-Offer",
 113         "DHCP-Request",
 114         "DHCP-Decline",
 115         "DHCP-Ack",
 116         "DHCP-NAK",
 117         "DHCP-Release",
 118         "DHCP-Inform",
 119         "DHCP-Force-Renew",
 120 };
 121
 122 static int dhcp_header_sizes[] = {
 123         1, 1, 1, 1,
 124         4, 2, 2, 4,
 125         4, 4, 4,
 126         DHCP_CHADDR_LEN,
 127         DHCP_SNAME_LEN,
 128         DHCP_FILE_LEN
 129 };
 130
 131
 132 /*
 133  *      Some clients silently ignore responses less than 300 bytes.
 134  */
 135 #define MIN_PACKET_SIZE (244)
 136 #define DEFAULT_PACKET_SIZE (300)
 137 #define MAX_PACKET_SIZE (1500 - 40)
 138
 139 #define DHCP_OPTION_FIELD (0)
 140 #define DHCP_FILE_FIELD   (1)
 141 #define DHCP_SNAME_FIELD  (2)
 142
 143 static uint8_t *dhcp_get_option(dhcp_packet_t *packet, size_t packet_size,
 144                                 unsigned int option)
 145
 146 {
 147         int overload = 0;
 148         int field = DHCP_OPTION_FIELD;
 149         size_t where, size;
 150         uint8_t *data = packet->options;
 151
 152         where = 0;
 153         size = packet_size - offsetof(dhcp_packet_t, options);
 154         data = &packet->options[where];
 155
 156         while (where < size) {
 157                 if (data[0] == 0) { /* padding */
 158                         where++;
 159                         continue;
 160                 }
 161
 162                 if (data[0] == 255) { /* end of options */
 163                         if ((field == DHCP_OPTION_FIELD) &&
 164                             (overload & DHCP_FILE_FIELD)) {
 165                                 data = packet->file;
 166                                 where = 0;
 167                                 size = sizeof(packet->file);
 168                                 field = DHCP_FILE_FIELD;
 169                                 continue;
 170
 171                         } else if ((field == DHCP_FILE_FIELD) &&
 172                                    (overload && DHCP_SNAME_FIELD)) {
 173                                 data = packet->sname;
 174                                 where = 0;
 175                                 size = sizeof(packet->sname);
 176                                 field = DHCP_SNAME_FIELD;
 177                                 continue;
 178                         }
 179
 180                         return NULL;
 181                 }
 182
 183                 /*
 184                  *      We MUST have a real option here.
 185                  */
 186                 if ((where + 2) > size) {
 187                         fr_strerror_printf("Options overflow field at %u",
 188                                            (unsigned int) (data - (uint8_t *) packet));
 189                         return NULL;
 190                 }
 191
 192                 if ((where + 2 + data[1]) > size) {
 193                         fr_strerror_printf("Option length overflows field at %u",
 194                                            (unsigned int) (data - (uint8_t *) packet));
 195                         return NULL;
 196                 }
 197
 198                 if (data[0] == option) return data;
 199
 200                 if (data[0] == 52) { /* overload sname and/or file */
 201                         overload = data[3];
 202                 }
 203
 204                 where += data[1] + 2;
 205                 data += data[1] + 2;
 206         }
 207
 208         return NULL;
 209 }
 210
 211 /*
 212  *      DHCPv4 is only for IPv4.  Broadcast only works if udpfromto is
 213  *      defined.
 214  */
 215 RADIUS_PACKET *fr_dhcp_recv(int sockfd)
 216 {
 217         uint32_t                magic;
 218         struct sockaddr_storage src;
 219         struct sockaddr_storage dst;
 220         socklen_t               sizeof_src;
 221         socklen_t               sizeof_dst;
 222         RADIUS_PACKET           *packet;
 223         int port;
 224         uint8_t                 *code;
 225
 226         packet = rad_alloc(0);
 227         if (!packet) {
 228                 fr_strerror_printf("Failed allocating packet");
 229                 return NULL;
 230         }
 231         memset(packet, 0, sizeof(*packet));
 232
 233         packet->data = malloc(MAX_PACKET_SIZE);
 234         if (!packet->data) {
 235                 fr_strerror_printf("Failed in malloc");
 236                 rad_free(&packet);
 237                 return NULL;
 238         }
 239
 240         packet->sockfd = sockfd;
 241         sizeof_src = sizeof(src);
 242 #ifdef WITH_UDPFROMTO
 243         sizeof_dst = sizeof(dst);
 244         packet->data_len = recvfromto(sockfd, packet->data, MAX_PACKET_SIZE, 0,
 245                                       (struct sockaddr *)&src, &sizeof_src,
 246                                       (struct sockaddr *)&dst, &sizeof_dst);
 247 #else
 248         packet->data_len = recvfrom(sockfd, packet->data, MAX_PACKET_SIZE, 0,
 249                                     (struct sockaddr *)&src, &sizeof_src);
 250 #endif
 251
 252         if (packet->data_len <= 0) {
 253                 fr_strerror_printf("Failed reading DHCP socket: %s", strerror(errno));
 254                 rad_free(&packet);
 255                 return NULL;
 256         }
 257
 258         if (packet->data_len < MIN_PACKET_SIZE) {
 259                 fr_strerror_printf("DHCP packet is too small (%d < %d)",
 260                                    (int) packet->data_len, MIN_PACKET_SIZE);
 261                 rad_free(&packet);
 262                 return NULL;
 263         }
 264
 265         if (packet->data[1] != 1) {
 266                 fr_strerror_printf("DHCP can only receive ethernet requests, not type %02x",
 267                       packet->data[1]);
 268                 rad_free(&packet);
 269                 return NULL;
 270         }
 271
 272         if (packet->data[2] != 6) {
 273                 fr_strerror_printf("Ethernet HW length is wrong length %d",
 274                         packet->data[2]);
 275                 rad_free(&packet);
 276                 return NULL;
 277         }
 278
 279         memcpy(&magic, packet->data + 236, 4);
 280         magic = ntohl(magic);
 281         if (magic != DHCP_OPTION_MAGIC_NUMBER) {
 282                 fr_strerror_printf("Cannot do BOOTP");
 283                 rad_free(&packet);
 284                 return NULL;
 285         }
 286
 287         /*
 288          *      Create unique keys for the packet.
 289          */
 290         memcpy(&magic, packet->data + 4, 4);
 291         packet->id = ntohl(magic);
 292
 293         code = dhcp_get_option((dhcp_packet_t *) packet->data,
 294                                packet->data_len, 53);
 295         if (!code) {
 296                 fr_strerror_printf("No message-type option was found in the packet");
 297                 rad_free(&packet);
 298                 return NULL;
 299         }
 300
 301         if ((code[1] < 1) || (code[2] == 0) || (code[2] > 8)) {
 302                 fr_strerror_printf("Unknown value for message-type option");
 303                 rad_free(&packet);
 304                 return NULL;
 305         }
 306
 307         packet->code = code[2] | PW_DHCP_OFFSET;
 308
 309         /*
 310          *      Create a unique vector from the MAC address and the
 311          *      DHCP opcode.  This is a hack for the RADIUS
 312          *      infrastructure in the rest of the server.
 313          *
 314          *      Note: packet->data[2] == 6, which is smaller than
 315          *      sizeof(packet->vector)
 316          *
 317          *      FIXME:  Look for client-identifier in packet,
 318          *      and use that, too?
 319          */
 320         memset(packet->vector, 0, sizeof(packet->vector));
 321         memcpy(packet->vector, packet->data + 28, packet->data[2]);
 322         packet->vector[packet->data[2]] = packet->code & 0xff;
 323
 324         /*
 325          *      FIXME: for DISCOVER / REQUEST: src_port == dst_port + 1
 326          *      FIXME: for OFFER / ACK       : src_port = dst_port - 1
 327          */
 328
 329         /*
 330          *      Unique keys are xid, client mac, and client ID?
 331          */
 332
 333         /*
 334          *      FIXME: More checks, like DHCP packet type?
 335          */
 336
 337         sizeof_dst = sizeof(dst);
 338
 339 #ifndef WITH_UDPFROMTO
 340         /*
 341          *      This should never fail...
 342          */
 343         if (getsockname(sockfd, (struct sockaddr *) &dst, &sizeof_dst) < 0) {
 344                 fr_strerror_printf("getsockname failed: %s", strerror(errno));
 345                 rad_free(&packet);
 346                 return NULL;
 347         }
 348 #endif
 349
 350         fr_sockaddr2ipaddr(&dst, sizeof_dst, &packet->dst_ipaddr, &port);
 351         packet->dst_port = port;
 352
 353         fr_sockaddr2ipaddr(&src, sizeof_src, &packet->src_ipaddr, &port);
 354         packet->src_port = port;
 355
 356         if (fr_debug_flag > 1) {
 357                 char type_buf[64];
 358                 const char *name = type_buf;
 359                 char src_ip_buf[256], dst_ip_buf[256];
 360
 361                 if ((packet->code >= PW_DHCP_DISCOVER) &&
 362                     (packet->code <= PW_DHCP_INFORM)) {
 363                         name = dhcp_message_types[packet->code - PW_DHCP_OFFSET];
 364                 } else {
 365                         snprintf(type_buf, sizeof(type_buf), "%d",
 366                                  packet->code - PW_DHCP_OFFSET);
 367                 }
 368
 369                 DEBUG("Received %s of id %08x from %s:%d to %s:%d\n",
 370                        name, (unsigned int) packet->id,
 371                        inet_ntop(packet->src_ipaddr.af,
 372                                  &packet->src_ipaddr.ipaddr,
 373                                  src_ip_buf, sizeof(src_ip_buf)),
 374                        packet->src_port,
 375                        inet_ntop(packet->dst_ipaddr.af,
 376                                  &packet->dst_ipaddr.ipaddr,
 377                                  dst_ip_buf, sizeof(dst_ip_buf)),
 378                        packet->dst_port);
 379         }
 380
 381         return packet;
 382 }
 383
 384
 385 /*
 386  *      Send a DHCP packet.
 387  */
 388 int fr_dhcp_send(RADIUS_PACKET *packet)
 389 {
 390         struct sockaddr_storage dst;
 391         socklen_t               sizeof_dst;
 392 #ifdef WITH_UDPFROMTO
 393         struct sockaddr_storage src;
 394         socklen_t               sizeof_src;
 395 #endif
 396
 397         if (!fr_ipaddr2sockaddr(&packet->dst_ipaddr, packet->dst_port,
 398                                 &dst, &sizeof_dst)) {
 399                 return -1;
 400         }
 401
 402         /*
 403          *      The client doesn't yet have an IP address, but is
 404          *      expecting an ethernet packet unicast to it's MAC
 405          *      address.  We need to build a raw frame.
 406          */
 407         if (packet->offset == 0) {
 408                 /*
 409                  *      FIXME: Insert code here!
 410                  */
 411         }
 412
 413 #ifndef WITH_UDPFROMTO
 414         /*
 415          *      Assume that the packet is encoded before sending it.
 416          */
 417         return sendto(packet->sockfd, packet->data, packet->data_len, 0,
 418                       (struct sockaddr *)&dst, sizeof_dst);
 419 #else
 420         if (!fr_ipaddr2sockaddr(&packet->src_ipaddr, packet->src_port,
 421                                 &src, &sizeof_src)) {
 422                 return -1;
 423         }
 424
 425         return sendfromto(packet->sockfd,
 426                           packet->data, packet->data_len, 0,
 427                           (struct sockaddr *)&src, sizeof_src,
 428                           (struct sockaddr *)&dst, sizeof_dst);
 429 #endif
 430 }
 431
 432 static int fr_dhcp_attr2vp(VALUE_PAIR *vp, const uint8_t *p, size_t alen);
 433
 434 static int decode_tlv(VALUE_PAIR *tlv, const uint8_t *data, size_t data_len)
 435 {
 436         const uint8_t *p;
 437         VALUE_PAIR *head, **tail, *vp;
 438
 439         /*
 440          *      Take a pass at parsing it.
 441          */
 442         p = data;
 443         while (p < (data + data_len)) {
 444                 if ((p + 2) > (data + data_len)) goto make_tlv;
 445
 446                 if ((p + p[1] + 2) > (data + data_len)) goto make_tlv;
 447                 p += 2 + p[1];
 448         }
 449
 450         /*
 451          *      Got here... must be well formed.
 452          */
 453         head = NULL;
 454         tail = &head;
 455
 456         p = data;
 457         while (p < (data + data_len)) {
 458                 vp = paircreate(tlv->da->attr | (p[0] << 8), DHCP_MAGIC_VENDOR);
 459                 if (!vp) {
 460                         pairfree(&head);
 461                         goto make_tlv;
 462                 }
 463
 464                 if (fr_dhcp_attr2vp(vp, p + 2, p[1]) < 0) {
 465                         pairfree(&head);
 466                         goto make_tlv;
 467                 }
 468
 469                 *tail = vp;
 470                 tail = &(vp->next);
 471                 p += 2 + p[1];
 472         }
 473
 474         /*
 475          *      The caller allocated TLV, so we need to copy the FIRST
 476          *      attribute over top of that.
 477          */
 478         if (head) {
 479                 memcpy(tlv, head, sizeof(*tlv));
 480                 head->next = NULL;
 481                 pairfree(&head);
 482         }
 483
 484         return 0;
 485
 486 make_tlv:
 487         tlv->vp_tlv = malloc(data_len);
 488         if (!tlv->vp_tlv) {
 489                 fr_strerror_printf("No memory");
 490                 return -1;
 491         }
 492         memcpy(tlv->vp_tlv, data, data_len);
 493         tlv->length = data_len;
 494
 495         return 0;
 496 }
 497
 498
 499 /*
 500  *      Decode ONE value into a VP
 501  */
 502 static int fr_dhcp_attr2vp(VALUE_PAIR *vp, const uint8_t *p, size_t alen)
 503 {
 504         switch (vp->da->type) {
 505         case PW_TYPE_BYTE:
 506                 if (alen != 1) goto raw;
 507                 vp->vp_integer = p[0];
 508                 break;
 509
 510         case PW_TYPE_SHORT:
 511                 if (alen != 2) goto raw;
 512                 vp->vp_integer = (p[0] << 8) | p[1];
 513                 break;
 514
 515         case PW_TYPE_INTEGER:
 516                 if (alen != 4) goto raw;
 517                 memcpy(&vp->vp_integer, p, 4);
 518                 vp->vp_integer = ntohl(vp->vp_integer);
 519                 break;
 520
 521         case PW_TYPE_IPADDR:
 522                 if (alen != 4) goto raw;
 523                 memcpy(&vp->vp_ipaddr, p , 4);
 524                 vp->length = 4;
 525                 break;
 526
 527         case PW_TYPE_STRING:
 528                 if (alen > 253) return -1;
 529                 memcpy(vp->vp_strvalue, p , alen);
 530                 vp->vp_strvalue[alen] = '\0';
 531                 break;
 532
 533         /*
 534          *      Value doesn't match up with attribute type, overwrite the
 535          *      vp's original DICT_ATTR with an unknown one.
 536          */
 537         raw:
 538                 if (pair2unknown(vp) < 0) return -1;
 539
 540         case PW_TYPE_OCTETS:
 541                 if (alen > 253) return -1;
 542                 memcpy(vp->vp_octets, p, alen);
 543                 break;
 544
 545         case PW_TYPE_TLV:
 546                 return decode_tlv(vp, p, alen);
 547
 548         default:
 549                 fr_strerror_printf("Internal sanity check %d %d", vp->da->type, __LINE__);
 550                 return -1;
 551         } /* switch over type */
 552
 553         vp->length = alen;
 554         return 0;
 555 }
 556
 557 ssize_t fr_dhcp_decode_options(uint8_t *data, size_t len, VALUE_PAIR **head)
 558 {
 559         int i;
 560         VALUE_PAIR *vp, **tail;
 561         uint8_t *p, *next;
 562         next = data;
 563
 564         *head = NULL;
 565         tail = head;
 566         /*
 567          *      FIXME: This should also check sname && file fields.
 568          *      See the dhcp_get_option() function above.
 569          */
 570         while (next < (data + len)) {
 571                 int num_entries, alen;
 572                 const DICT_ATTR *da;
 573
 574                 p = next;
 575
 576                 if (*p == 0) break;
 577                 if (*p == 255) break; /* end of options signifier */
 578                 if ((p + 2) > (data + len)) break;
 579
 580                 next = p + 2 + p[1];
 581
 582                 if (p[1] >= 253) {
 583                         fr_strerror_printf("Attribute too long %u %u",
 584                                            p[0], p[1]);
 585                         continue;
 586                 }
 587
 588                 da = dict_attrbyvalue(p[0], DHCP_MAGIC_VENDOR);
 589                 if (!da) {
 590                         fr_strerror_printf("Attribute not in our dictionary: %u",
 591                                            p[0]);
 592                         continue;
 593                 }
 594
 595                 vp = NULL;
 596                 num_entries = 1;
 597                 alen = p[1];
 598                 p += 2;
 599
 600                 /*
 601                  *      Could be an array of bytes, integers, etc.
 602                  */
 603                 if (da->flags.array) {
 604                         switch (da->type) {
 605                         case PW_TYPE_BYTE:
 606                                 num_entries = alen;
 607                                 alen = 1;
 608                                 break;
 609
 610                         case PW_TYPE_SHORT: /* ignore any trailing data */
 611                                 num_entries = alen >> 1;
 612                                 alen = 2;
 613                                 break;
 614
 615                         case PW_TYPE_IPADDR:
 616                         case PW_TYPE_INTEGER:
 617                         case PW_TYPE_DATE: /* ignore any trailing data */
 618                                 num_entries = alen >> 2;
 619                                 alen = 4;
 620                                 break;
 621
 622                         default:
 623
 624                                 break; /* really an internal sanity failure */
 625                         }
 626                 }
 627
 628                 /*
 629                  *      Loop over all of the entries, building VPs
 630                  */
 631                 for (i = 0; i < num_entries; i++) {
 632                         vp = pairmake(da->name, NULL, T_OP_ADD);
 633                         if (!vp) {
 634                                 fr_strerror_printf("Cannot build attribute %s",
 635                                         fr_strerror());
 636                                 pairfree(head);
 637                                 return -1;
 638                         }
 639
 640                         /*
 641                          *      Hack for ease of use.
 642                          */
 643                         if (fr_dhcp_attr2vp(vp, p, alen) < 0) {
 644                                 pairfree(&vp);
 645                                 pairfree(head);
 646                                 return -1;
 647                         }
 648
 649                         *tail = vp;
 650                         while (*tail) {
 651                                 debug_pair(*tail);
 652                                 tail = &(*tail)->next;
 653                         }
 654                         p += alen;
 655                 } /* loop over array entries */
 656         } /* loop over the entire packet */
 657
 658         return next - data;
 659 }
 660
 661 int fr_dhcp_decode(RADIUS_PACKET *packet)
 662 {
 663         size_t i;
 664         uint8_t *p;
 665         uint32_t giaddr;
 666         VALUE_PAIR *head, *vp, **tail;
 667         VALUE_PAIR *maxms, *mtu;
 668
 669         head = NULL;
 670         tail = &head;
 671         p = packet->data;
 672
 673         if ((fr_debug_flag > 2) && fr_log_fp) {
 674                 for (i = 0; i < packet->data_len; i++) {
 675                         if ((i & 0x0f) == 0x00) fprintf(fr_log_fp, "%d: ", (int) i);
 676                         fprintf(fr_log_fp, "%02x ", packet->data[i]);
 677                         if ((i & 0x0f) == 0x0f) fprintf(fr_log_fp, "\n");
 678                 }
 679                 fprintf(fr_log_fp, "\n");
 680         }
 681
 682         if (packet->data[1] != 1) {
 683                 fr_strerror_printf("Packet is not Ethernet: %u",
 684                       packet->data[1]);
 685                 return -1;
 686         }
 687
 688         /*
 689          *      Decode the header.
 690          */
 691         for (i = 0; i < 14; i++) {
 692                 vp = pairmake(dhcp_header_names[i], NULL, T_OP_EQ);
 693                 if (!vp) {
 694                         fr_strerror_printf("Parse error %s", fr_strerror());
 695                         pairfree(&head);
 696                         return -1;
 697                 }
 698
 699                 if ((i == 11) &&
 700                     (packet->data[1] == 1) &&
 701                     (packet->data[2] != 6)) {
 702                         fr_strerror_printf("chaddr of incorrect length for ethernet");
 703                 }
 704
 705                 switch (vp->da->type) {
 706                 case PW_TYPE_BYTE:
 707                         vp->vp_integer = p[0];
 708                         vp->length = 1;
 709                         break;
 710
 711                 case PW_TYPE_SHORT:
 712                         vp->vp_integer = (p[0] << 8) | p[1];
 713                         vp->length = 2;
 714                         break;
 715
 716                 case PW_TYPE_INTEGER:
 717                         memcpy(&vp->vp_integer, p, 4);
 718                         vp->vp_integer = ntohl(vp->vp_integer);
 719                         vp->length = 4;
 720                         break;
 721
 722                 case PW_TYPE_IPADDR:
 723                         memcpy(&vp->vp_ipaddr, p, 4);
 724                         vp->length = 4;
 725                         break;
 726
 727                 case PW_TYPE_STRING:
 728                         memcpy(vp->vp_strvalue, p, dhcp_header_sizes[i]);
 729                         vp->vp_strvalue[dhcp_header_sizes[i]] = '\0';
 730                         vp->length = strlen(vp->vp_strvalue);
 731                         if (vp->length == 0) {
 732                                 pairfree(&vp);
 733                         }
 734                         break;
 735
 736                 case PW_TYPE_OCTETS:
 737                         memcpy(vp->vp_octets, p, packet->data[2]);
 738                         vp->length = packet->data[2];
 739                         break;
 740
 741                 case PW_TYPE_ETHERNET:
 742                         memcpy(vp->vp_ether, p, sizeof(vp->vp_ether));
 743                         vp->length = sizeof(vp->vp_ether);
 744                         break;
 745
 746                 default:
 747                         fr_strerror_printf("BAD TYPE %d", vp->da->type);
 748                         pairfree(&vp);
 749                         break;
 750                 }
 751                 p += dhcp_header_sizes[i];
 752
 753                 if (!vp) continue;
 754
 755                 debug_pair(vp);
 756                 *tail = vp;
 757                 tail = &vp->next;
 758         }
 759
 760         /*
 761          *      Loop over the options.
 762          */
 763
 764         /*
 765          *  Nothing uses tail after this call, if it does in the future
 766          *  it'll need to find the new tail...
 767          */
 768         if (fr_dhcp_decode_options(packet->data + 240, packet->data_len - 240,
 769                                    tail) < 0) {
 770                 return -1;
 771         }
 772
 773         /*
 774          *      If DHCP request, set ciaddr to zero.
 775          */
 776
 777         /*
 778          *      Set broadcast flag for broken vendors, but only if
 779          *      giaddr isn't set.
 780          */
 781         memcpy(&giaddr, packet->data + 24, sizeof(giaddr));
 782         if (giaddr == htonl(INADDR_ANY)) {
 783                 /*
 784                  *      DHCP Opcode is request
 785                  */
 786                 vp = pairfind(head, 256, DHCP_MAGIC_VENDOR, TAG_ANY);
 787                 if (vp && vp->vp_integer == 3) {
 788                         /*
 789                          *      Vendor is "MSFT 98"
 790                          */
 791                         vp = pairfind(head, 63, DHCP_MAGIC_VENDOR, TAG_ANY);
 792                         if (vp && (strcmp(vp->vp_strvalue, "MSFT 98") == 0)) {
 793                                 vp = pairfind(head, 262, DHCP_MAGIC_VENDOR, TAG_ANY);
 794
 795                                 /*
 796                                  *      Reply should be broadcast.
 797                                  */
 798                                 if (vp) vp->vp_integer |= 0x8000;
 799                                 packet->data[10] |= 0x80;
 800                         }
 801                 }
 802         }
 803
 804         /*
 805          *      FIXME: Nuke attributes that aren't used in the normal
 806          *      header for discover/requests.
 807          */
 808         packet->vps = head;
 809
 810         /*
 811          *      Client can request a LARGER size, but not a smaller
 812          *      one.  They also cannot request a size larger than MTU.
 813          */
 814         maxms = pairfind(packet->vps, 57, DHCP_MAGIC_VENDOR, TAG_ANY);
 815         mtu = pairfind(packet->vps, 26, DHCP_MAGIC_VENDOR, TAG_ANY);
 816
 817         if (mtu && (mtu->vp_integer < DEFAULT_PACKET_SIZE)) {
 818                 fr_strerror_printf("DHCP Fatal: Client says MTU is smaller than minimum permitted by the specification.");
 819                 return -1;
 820         }
 821
 822         if (maxms && (maxms->vp_integer < DEFAULT_PACKET_SIZE)) {
 823                 fr_strerror_printf("DHCP WARNING: Client says maximum message size is smaller than minimum permitted by the specification: fixing it");
 824                 maxms->vp_integer = DEFAULT_PACKET_SIZE;
 825         }
 826
 827         if (maxms && mtu && (maxms->vp_integer > mtu->vp_integer)) {
 828                 fr_strerror_printf("DHCP WARNING: Client says MTU is smaller than maximum message size: fixing it");
 829                 maxms->vp_integer = mtu->vp_integer;
 830         }
 831
 832         if (fr_debug_flag > 0) {
 833                 for (vp = packet->vps; vp != NULL; vp = vp->next) {
 834
 835                 }
 836         }
 837
 838         if (fr_debug_flag) fflush(stdout);
 839
 840         return 0;
 841 }
 842
 843
 844 static int attr_cmp(const void *one, const void *two)
 845 {
 846         const VALUE_PAIR * const *a = one;
 847         const VALUE_PAIR * const *b = two;
 848
 849         /*
 850          *      DHCP-Message-Type is first, for simplicity.
 851          */
 852         if (((*a)->da->attr == 53) &&
 853             (*b)->da->attr != 53) return -1;
 854
 855         /*
 856          *      Relay-Agent is last
 857          */
 858         if (((*a)->da->attr == 82) &&
 859             (*b)->da->attr != 82) return +1;
 860
 861         return ((*a)->da->attr - (*b)->da->attr);
 862 }
 863
 864
 865 static size_t fr_dhcp_vp2attr(VALUE_PAIR *vp, uint8_t *p, size_t room)
 866 {
 867         size_t length;
 868         uint32_t lvalue;
 869
 870         /*
 871          *      FIXME: Check room!
 872          */
 873         room = room;            /* -Wunused */
 874
 875         /*
 876          *      Search for all attributes of the same
 877          *      type, and pack them into the same
 878          *      attribute.
 879          */
 880         switch (vp->da->type) {
 881         case PW_TYPE_BYTE:
 882                 length = 1;
 883                 *p = vp->vp_integer & 0xff;
 884                 break;
 885
 886         case PW_TYPE_SHORT:
 887                 length = 2;
 888                 p[0] = (vp->vp_integer >> 8) & 0xff;
 889                 p[1] = vp->vp_integer & 0xff;
 890                 break;
 891
 892         case PW_TYPE_INTEGER:
 893                 length = 4;
 894                 lvalue = htonl(vp->vp_integer);
 895                 memcpy(p, &lvalue, 4);
 896                 break;
 897
 898         case PW_TYPE_IPADDR:
 899                 length = 4;
 900                 memcpy(p, &vp->vp_ipaddr, 4);
 901                 break;
 902
 903         case PW_TYPE_ETHERNET:
 904                 length = 6;
 905                 memcpy(p, &vp->vp_ether, 6);
 906                 break;
 907
 908         case PW_TYPE_STRING:
 909                 memcpy(p, vp->vp_strvalue, vp->length);
 910                 length = vp->length;
 911                 break;
 912
 913         case PW_TYPE_TLV:       /* FIXME: split it on 255? */
 914                 memcpy(p, vp->vp_tlv, vp->length);
 915                 length = vp->length;
 916                 break;
 917
 918         case PW_TYPE_OCTETS:
 919                 memcpy(p, vp->vp_octets, vp->length);
 920                 length = vp->length;
 921                 break;
 922
 923         default:
 924                 fr_strerror_printf("BAD TYPE2 %d", vp->da->type);
 925                 length = 0;
 926                 break;
 927         }
 928
 929         return length;
 930 }
 931
 932 static VALUE_PAIR *fr_dhcp_vp2suboption(VALUE_PAIR *vps)
 933 {
 934         int length;
 935         unsigned int attribute;
 936         uint8_t *ptr;
 937         VALUE_PAIR *vp, *tlv;
 938
 939         attribute = vps->da->attr & 0xffff00ff;
 940
 941         tlv = paircreate(attribute, DHCP_MAGIC_VENDOR);
 942         if (!tlv) return NULL;
 943
 944         tlv->length = 0;
 945         for (vp = vps; vp != NULL; vp = vp->next) {
 946                 /*
 947                  *      Group the attributes ONLY until we see a
 948                  *      non-TLV attribute.
 949                  */
 950                 if (!vp->da->flags.is_tlv ||
 951                     vp->da->flags.extended ||
 952                     ((vp->da->attr & 0xffff00ff) != attribute)) {
 953                         break;
 954                 }
 955
 956                 tlv->length += vp->length + 2;
 957         }
 958
 959         if (!tlv->length) {
 960                 pairfree(&tlv);
 961                 return NULL;
 962         }
 963
 964         tlv->vp_tlv = malloc(tlv->length);
 965         if (!tlv->vp_tlv) {
 966                 pairfree(&tlv);
 967                 return NULL;
 968         }
 969
 970         ptr = tlv->vp_tlv;
 971         for (vp = vps; vp != NULL; vp = vp->next) {
 972                 if (!vp->da->flags.is_tlv ||
 973                     vp->da->flags.extended ||
 974                     ((vp->da->attr & 0xffff00ff) != attribute)) {
 975                         break;
 976                 }
 977
 978                 length = fr_dhcp_vp2attr(vp, ptr + 2,
 979                                          tlv->vp_tlv + tlv->length - ptr);
 980                 if (length > 255) return NULL;
 981
 982                 /*
 983                  *      Pack the attribute.
 984                  */
 985                 ptr[0] = (vp->da->attr & 0xff00) >> 8;
 986                 ptr[1] = length;
 987
 988                 ptr += length + 2;
 989         }
 990
 991         return tlv;
 992 }
 993
 994
 995 int fr_dhcp_encode(RADIUS_PACKET *packet, RADIUS_PACKET *original)
 996 {
 997         unsigned int i, num_vps;
 998         uint8_t *p;
 999         VALUE_PAIR *vp;
1000         uint32_t lvalue, mms;
1001         size_t dhcp_size, length;
1002         dhcp_packet_t *dhcp;
1003
1004         if (packet->data) return 0;
1005
1006         packet->data = malloc(MAX_PACKET_SIZE);
1007         if (!packet->data) return -1;
1008
1009         packet->data_len = MAX_PACKET_SIZE;
1010
1011         if (packet->code == 0) packet->code = PW_DHCP_NAK;
1012
1013         /*
1014          *      If there's a request, use it as a template.
1015          *      Otherwise, assume that the caller has set up
1016          *      everything appropriately.
1017          */
1018         if (original) {
1019                 packet->dst_ipaddr.af = AF_INET;
1020                 packet->src_ipaddr.af = AF_INET;
1021
1022                 packet->dst_port = original->src_port;
1023                 packet->src_port = original->dst_port;
1024
1025                 /*
1026                  *      Note that for DHCP, we NEVER send the response
1027                  *      to the source IP address of the request.  It
1028                  *      may have traversed multiple relays, and we
1029                  *      need to send the request to the relay closest
1030                  *      to the client.
1031                  *
1032                  *      if giaddr, send to giaddr.
1033                  *      if NAK, send broadcast.
1034                  *      if broadcast flag, send broadcast.
1035                  *      if ciaddr is empty, send broadcast.
1036                  *      otherwise unicast to ciaddr.
1037                  */
1038
1039                 /*
1040                  *      FIXME: alignment issues.  We likely don't want to
1041                  *      de-reference the packet structure directly..
1042                  */
1043                 dhcp = (dhcp_packet_t *) original->data;
1044
1045                 /*
1046                  *      Default to sending it via sendto(), without using
1047                  *      raw sockets.
1048                  */
1049                 packet->offset = 1;
1050
1051                 if (dhcp->giaddr != htonl(INADDR_ANY)) {
1052                         packet->dst_ipaddr.ipaddr.ip4addr.s_addr = dhcp->giaddr;
1053
1054                         if (dhcp->giaddr != htonl(INADDR_LOOPBACK)) {
1055                                 packet->dst_port = original->dst_port;
1056                         } else {
1057                                 packet->dst_port = original->src_port; /* debugging */
1058                         }
1059
1060                 } else if ((packet->code == PW_DHCP_NAK) ||
1061                            ((dhcp->flags & 0x8000) != 0) ||
1062                            (dhcp->ciaddr == htonl(INADDR_ANY))) {
1063                         /*
1064                          *      The kernel will take care of sending it to
1065                          *      the broadcast MAC.
1066                          */
1067                         packet->dst_ipaddr.ipaddr.ip4addr.s_addr = htonl(INADDR_BROADCAST);
1068
1069                 } else {
1070                         /*
1071                          *      It was broadcast to us: we need to
1072                          *      broadcast the response.
1073                          */
1074                         if (packet->src_ipaddr.ipaddr.ip4addr.s_addr != dhcp->ciaddr) {
1075                                 packet->offset = 0;
1076                         }
1077                         packet->dst_ipaddr.ipaddr.ip4addr.s_addr = dhcp->ciaddr;
1078                 }
1079
1080                 /*
1081                  *      Rewrite the source IP to be our own, if we know it.
1082                  */
1083                 if (packet->src_ipaddr.ipaddr.ip4addr.s_addr == htonl(INADDR_BROADCAST)) {
1084                         packet->src_ipaddr.ipaddr.ip4addr.s_addr = htonl(INADDR_ANY);
1085                 }
1086         } else {
1087                 memset(packet->data, 0, packet->data_len);
1088         }
1089
1090         if (fr_debug_flag > 1) {
1091                 char type_buf[64];
1092                 const char *name = type_buf;
1093                 char src_ip_buf[256], dst_ip_buf[256];
1094
1095                 if ((packet->code >= PW_DHCP_DISCOVER) &&
1096                     (packet->code <= PW_DHCP_INFORM)) {
1097                         name = dhcp_message_types[packet->code - PW_DHCP_OFFSET];
1098                 } else {
1099                         snprintf(type_buf, sizeof(type_buf), "%d",
1100                                  packet->code - PW_DHCP_OFFSET);
1101                 }
1102
1103                 DEBUG("Sending %s of id %08x from %s:%d to %s:%d\n",
1104                        name, (unsigned int) packet->id,
1105                        inet_ntop(packet->src_ipaddr.af,
1106                                  &packet->src_ipaddr.ipaddr,
1107                                  src_ip_buf, sizeof(src_ip_buf)),
1108                        packet->src_port,
1109                        inet_ntop(packet->dst_ipaddr.af,
1110                                  &packet->dst_ipaddr.ipaddr,
1111                                  dst_ip_buf, sizeof(dst_ip_buf)),
1112                        packet->dst_port);
1113
1114                 if (fr_debug_flag) {
1115                         for (i = 256; i < 269; i++) {
1116                                 vp = pairfind(packet->vps, i, DHCP_MAGIC_VENDOR, TAG_ANY);
1117                                 if (!vp) continue;
1118
1119                                 debug_pair(vp);
1120                         }
1121                 }
1122         }
1123
1124         p = packet->data;
1125
1126         mms = DEFAULT_PACKET_SIZE; /* maximum message size */
1127
1128         if (original) {
1129                 /*
1130                  *      Clients can request a LARGER size, but not a
1131                  *      smaller one.  They also cannot request a size
1132                  *      larger than MTU.
1133                  */
1134                 vp = pairfind(original->vps, 57, DHCP_MAGIC_VENDOR, TAG_ANY);
1135                 if (vp && (vp->vp_integer > mms)) {
1136                         mms = vp->vp_integer;
1137
1138                         if (mms > MAX_PACKET_SIZE) mms = MAX_PACKET_SIZE;
1139                 }
1140         }
1141
1142         /*
1143          *      RFC 3118: Authentication option.
1144          */
1145         vp = pairfind(packet->vps, 90, DHCP_MAGIC_VENDOR, TAG_ANY);
1146         if (vp) {
1147                 if (vp->length < 2) {
1148                         memset(vp->vp_octets + vp->length, 0,
1149                                2 - vp->length);
1150                         vp->length = 2;
1151                 }
1152
1153                 if (vp->length < 3) {
1154                         struct timeval tv;
1155
1156                         gettimeofday(&tv, NULL);
1157                         vp->vp_octets[2] = 0;
1158                         timeval2ntp(&tv, vp->vp_octets + 3);
1159                         vp->length = 3 + 8;
1160                 }
1161
1162                 /*
1163                  *      Configuration token (clear-text token)
1164                  */
1165                 if (vp->vp_octets[0] == 0) {
1166                         VALUE_PAIR *pass;
1167                         vp->vp_octets[1] = 0;
1168
1169                         pass = pairfind(packet->vps, PW_CLEARTEXT_PASSWORD, DHCP_MAGIC_VENDOR, TAG_ANY);
1170                         if (pass) {
1171                                 length = pass->length;
1172                                 if ((length + 11) > sizeof(vp->vp_octets)) {
1173                                         length -= ((length + 11) - sizeof(vp->vp_octets));
1174                                 }
1175                                 memcpy(vp->vp_octets + 11, pass->vp_strvalue,
1176                                        length);
1177                                 vp->length = length + 11;
1178                         } else {
1179                                 vp->length = 11 + 8;
1180                                 memset(vp->vp_octets + 11, 0, 8);
1181                                 vp->length = 11 + 8;
1182                         }
1183                 } else {        /* we don't support this type! */
1184                         fr_strerror_printf("DHCP-Authentication %d unsupported",
1185                                 vp->vp_octets[0]);
1186                 }
1187         }
1188
1189         vp = pairfind(packet->vps, 256, DHCP_MAGIC_VENDOR, TAG_ANY);
1190         if (vp) {
1191                 *p++ = vp->vp_integer & 0xff;
1192         } else {
1193                 if (!original) {
1194                         *p++ = 1;       /* client message */
1195                 } else {
1196                         *p++ = 2;       /* server message */
1197                 }
1198         }
1199         *p++ = 1;               /* hardware type = ethernet */
1200         *p++ = 6;               /* 6 bytes of ethernet */
1201
1202         vp = pairfind(packet->vps, 259, DHCP_MAGIC_VENDOR, TAG_ANY);
1203         if (vp) {
1204                 *p++ = vp->vp_integer & 0xff;
1205         } else {
1206                 *p++ = 0;               /* hops */
1207         }
1208
1209         if (original) { /* Xid */
1210                 memcpy(p, original->data + 4, 4);
1211         } else {
1212                 lvalue = fr_rand();
1213                 memcpy(p, &lvalue, 4);
1214         }
1215         p += 4;
1216
1217         memset(p, 0, 2);        /* secs are zero */
1218         p += 2;
1219
1220         if (original) {
1221                 memcpy(p, original->data + 10, 6); /* copy flags && ciaddr */
1222         }
1223
1224         /*
1225          *      Allow the admin to set the broadcast flag.
1226          */
1227         vp = pairfind(packet->vps, 262, DHCP_MAGIC_VENDOR, TAG_ANY);
1228         if (vp) {
1229                 p[0] |= (vp->vp_integer & 0xff00) >> 8;
1230                 p[1] |= (vp->vp_integer & 0xff);
1231         }
1232
1233         p += 6;
1234
1235         /*
1236          *      Set client IP address.
1237          */
1238         vp = pairfind(packet->vps, 264, DHCP_MAGIC_VENDOR, TAG_ANY); /* Your IP address */
1239         if (vp) {
1240                 lvalue = vp->vp_ipaddr;
1241         } else {
1242                 lvalue = htonl(INADDR_ANY);
1243         }
1244         memcpy(p, &lvalue, 4);  /* your IP address */
1245         p += 4;
1246
1247         vp = pairfind(packet->vps, 265, DHCP_MAGIC_VENDOR, TAG_ANY); /* server IP address */
1248         if (!vp) vp = pairfind(packet->vps, 54, DHCP_MAGIC_VENDOR, TAG_ANY); /* identifier */
1249         if (vp) {
1250                 lvalue = vp->vp_ipaddr;
1251         } else {
1252                 lvalue = htonl(INADDR_ANY);
1253         }
1254         memcpy(p, &lvalue, 4);  /* Server IP address */
1255         p += 4;
1256
1257         if (original) {
1258                 memcpy(p, original->data + 24, 4); /* copy gateway IP address */
1259         } else {
1260                 vp = pairfind(packet->vps, 266, DHCP_MAGIC_VENDOR, TAG_ANY);
1261                 if (vp) {
1262                         lvalue = vp->vp_ipaddr;
1263                 } else {
1264                         lvalue = htonl(INADDR_NONE);
1265                 }
1266                 memcpy(p, &lvalue, 4);
1267         }
1268         p += 4;
1269
1270         if (original) {
1271                 memcpy(p, original->data + 28, DHCP_CHADDR_LEN);
1272         } else {
1273                 vp = pairfind(packet->vps, 267, DHCP_MAGIC_VENDOR, TAG_ANY);
1274                 if (vp) {
1275                         if (vp->length > DHCP_CHADDR_LEN) {
1276                                 memcpy(p, vp->vp_octets, DHCP_CHADDR_LEN);
1277                         } else {
1278                                 memcpy(p, vp->vp_octets, vp->length);
1279                         }
1280                 }
1281         }
1282         p += DHCP_CHADDR_LEN;
1283
1284         /*
1285          *      Zero our sname && filename fields.
1286          */
1287         memset(p, 0, DHCP_SNAME_LEN + DHCP_FILE_LEN);
1288         p += DHCP_SNAME_LEN;
1289
1290         /*
1291          *      Copy over DHCP-Boot-Filename.
1292          *
1293          *      FIXME: This copy should be delayed until AFTER the options
1294          *      have been processed.  If there are too many options for
1295          *      the packet, then they go into the sname && filename fields.
1296          *      When that happens, the boot filename is passed as an option,
1297          *      instead of being placed verbatim in the filename field.
1298          */
1299         vp = pairfind(packet->vps, 269, DHCP_MAGIC_VENDOR, TAG_ANY);
1300         if (vp) {
1301                 if (vp->length > DHCP_FILE_LEN) {
1302                         memcpy(p, vp->vp_strvalue, DHCP_FILE_LEN);
1303                 } else {
1304                         memcpy(p, vp->vp_strvalue, vp->length);
1305                 }
1306         }
1307         p += DHCP_FILE_LEN;
1308
1309         lvalue = htonl(DHCP_OPTION_MAGIC_NUMBER); /* DHCP magic number */
1310         memcpy(p, &lvalue, 4);
1311         p += 4;
1312
1313         /*
1314          *      Print the header.
1315          */
1316         if (fr_debug_flag > 1) {
1317                 uint8_t *pp = p;
1318
1319                 p = packet->data;
1320
1321                 for (i = 0; i < 14; i++) {
1322                         vp = pairmake(dhcp_header_names[i], NULL, T_OP_EQ);
1323                         if (!vp) {
1324                                 fr_strerror_printf("Parse error %s", fr_strerror());
1325                                 return -1;
1326                         }
1327
1328                         switch (vp->da->type) {
1329                         case PW_TYPE_BYTE:
1330                                 vp->vp_integer = p[0];
1331                                 vp->length = 1;
1332                                 break;
1333
1334                         case PW_TYPE_SHORT:
1335                                 vp->vp_integer = (p[0] << 8) | p[1];
1336                                 vp->length = 2;
1337                                 break;
1338
1339                         case PW_TYPE_INTEGER:
1340                                 memcpy(&vp->vp_integer, p, 4);
1341                                 vp->vp_integer = ntohl(vp->vp_integer);
1342                                 vp->length = 4;
1343                                 break;
1344
1345                         case PW_TYPE_IPADDR:
1346                                 memcpy(&vp->vp_ipaddr, p, 4);
1347                                 vp->length = 4;
1348                                 break;
1349
1350                         case PW_TYPE_STRING:
1351                                 memcpy(vp->vp_strvalue, p, dhcp_header_sizes[i]);
1352                                 vp->vp_strvalue[dhcp_header_sizes[i]] = '\0';
1353                                 vp->length = strlen(vp->vp_strvalue);
1354                                 break;
1355
1356                         case PW_TYPE_OCTETS: /* only for Client HW Address */
1357                                 memcpy(vp->vp_octets, p, packet->data[2]);
1358                                 vp->length = packet->data[2];
1359                                 break;
1360
1361                         case PW_TYPE_ETHERNET: /* only for Client HW Address */
1362                                 memcpy(vp->vp_ether, p, sizeof(vp->vp_ether));
1363                                 vp->length = sizeof(vp->vp_ether);
1364                                 break;
1365
1366                         default:
1367                                 fr_strerror_printf("Internal sanity check failed %d %d", vp->da->type, __LINE__);
1368                                 pairfree(&vp);
1369                                 break;
1370                         }
1371
1372                         p += dhcp_header_sizes[i];
1373
1374                         debug_pair(vp);
1375                         pairfree(&vp);
1376                 }
1377
1378                 /*
1379                  *      Jump over DHCP magic number, response, etc.
1380                  */
1381                 p = pp;
1382         }
1383
1384         /*
1385          *      Before packing the attributes, re-order them so that
1386          *      the array ones are all contiguous.  This simplifies
1387          *      the later code.
1388          */
1389         num_vps = 0;
1390         for (vp = packet->vps; vp != NULL; vp = vp->next) {
1391                 num_vps++;
1392         }
1393         if (num_vps > 1) {
1394                 VALUE_PAIR **array, **last;
1395
1396                 array = malloc(num_vps * sizeof(VALUE_PAIR *));
1397
1398                 i = 0;
1399                 for (vp = packet->vps; vp != NULL; vp = vp->next) {
1400                         array[i++] = vp;
1401                 }
1402
1403                 /*
1404                  *      Sort the attributes.
1405                  */
1406                 qsort(array, (size_t) num_vps, sizeof(VALUE_PAIR *),
1407                       attr_cmp);
1408
1409                 last = &packet->vps;
1410                 for (i = 0; i < num_vps; i++) {
1411                         *last = array[i];
1412                         array[i]->next = NULL;
1413                         last = &(array[i]->next);
1414                 }
1415                 free(array);
1416         }
1417
1418         p[0] = 0x35;            /* DHCP-Message-Type */
1419         p[1] = 1;
1420         p[2] = packet->code - PW_DHCP_OFFSET;
1421         p += 3;
1422
1423         /*
1424          *      Pack in the attributes.
1425          */
1426         vp = packet->vps;
1427         while (vp) {
1428                 unsigned int num_entries = 1;
1429                 VALUE_PAIR *same;
1430                 uint8_t *plength, *pattr;
1431
1432                 if (vp->da->vendor != DHCP_MAGIC_VENDOR) goto next;
1433                 if (vp->da->attr == 53) goto next; /* already done */
1434                 if ((vp->da->attr > 255) &&
1435                     (DHCP_BASE_ATTR(vp->da->attr) != PW_DHCP_OPTION_82)) goto next;
1436
1437                 debug_pair(vp);
1438                 if (vp->da->flags.extended) goto next;
1439
1440                 length = vp->length;
1441
1442                 for (same = vp->next; same != NULL; same = same->next) {
1443                         if (same->da->attr != vp->da->attr) break;
1444                         num_entries++;
1445                 }
1446
1447                 /*
1448                  *      For client-identifier
1449                  * @fixme What's this meant to be doing?!
1450                  */
1451 #if 0
1452                 if ((vp->da->type == PW_TYPE_ETHERNET) &&
1453                     (vp->length == 6) &&
1454                     (num_entries == 1)) {
1455                         vp->da->type = PW_TYPE_OCTETS;
1456                         memmove(vp->vp_octets + 1, vp->vp_octets, 6);
1457                         vp->vp_octets[0] = 1;
1458                 }
1459 #endif
1460                 pattr = p;
1461                 *(p++) = vp->da->attr & 0xff;
1462                 plength = p;
1463                 *(p++) = 0;     /* header isn't included in attr length */
1464
1465                 for (i = 0; i < num_entries; i++) {
1466                         debug_pair(vp);
1467
1468                         if (vp->da->flags.is_tlv) {
1469                                 VALUE_PAIR *tlv;
1470
1471                                 /*
1472                                  *      Should NOT have been encoded yet!
1473                                  */
1474                                 tlv = fr_dhcp_vp2suboption(vp);
1475
1476                                 /*
1477                                  *      Ignore it if there's an issue
1478                                  *      encoding it.
1479                                  */
1480                                 if (!tlv) goto next;
1481
1482                                 tlv->next = vp->next;
1483                                 vp->next = tlv;
1484                                 vp = tlv;
1485                         }
1486
1487                         length = fr_dhcp_vp2attr(vp, p, 0);
1488
1489                         /*
1490                          *      This will never happen due to FreeRADIUS
1491                          *      limitations: sizeof(vp->vp_octets) < 255
1492                          */
1493                         if (length > 255) {
1494                                 fr_strerror_printf("WARNING Ignoring too long attribute %s!", vp->da->name);
1495                                 break;
1496                         }
1497
1498                         /*
1499                          *      More than one attribute of the same type
1500                          *      in a row: they are packed together
1501                          *      into the same TLV.  If we overflow,
1502                          *      go bananas!
1503                          */
1504                         if ((*plength + length) > 255) {
1505                                 fr_strerror_printf("WARNING Ignoring too long attribute %s!", vp->da->name);
1506                                 break;
1507                         }
1508
1509                         *plength += length;
1510                         p += length;
1511
1512                         if (vp->next &&
1513                             (vp->next->da->attr == vp->da->attr))
1514                                 vp = vp->next;
1515                 } /* loop over num_entries */
1516
1517         next:
1518                 vp = vp->next;
1519         }
1520
1521         p[0] = 0xff;            /* end of option option */
1522         p[1] = 0x00;
1523         p += 2;
1524         dhcp_size = p - packet->data;
1525
1526         /*
1527          *      FIXME: if (dhcp_size > mms),
1528          *        then we put the extra options into the "sname" and "file"
1529          *        fields, AND set the "end option option" in the "options"
1530          *        field.  We also set the "overload option",
1531          *        and put options into the "file" field, followed by
1532          *        the "sname" field.  Where each option is completely
1533          *        enclosed in the "file" and/or "sname" field, AND
1534          *        followed by the "end of option", and MUST be followed
1535          *        by padding option.
1536          *
1537          *      Yuck.  That sucks...
1538          */
1539         packet->data_len = dhcp_size;
1540
1541         if (original) {
1542                 /*
1543                  *      FIXME: This may set it to broadcast, which we don't
1544                  *      want.  Instead, set it to the real address of the
1545                  *      socket.
1546                  */
1547                 packet->src_ipaddr = original->dst_ipaddr;
1548
1549                 packet->sockfd = original->sockfd;
1550         }
1551
1552         if (packet->data_len < DEFAULT_PACKET_SIZE) {
1553                 memset(packet->data + packet->data_len, 0,
1554                        DEFAULT_PACKET_SIZE - packet->data_len);
1555                 packet->data_len = DEFAULT_PACKET_SIZE;
1556         }
1557
1558         if ((fr_debug_flag > 2) && fr_log_fp) {
1559                 for (i = 0; i < packet->data_len; i++) {
1560                         if ((i & 0x0f) == 0x00) fprintf(fr_log_fp, "%d: ", i);
1561                         fprintf(fr_log_fp, "%02x ", packet->data[i]);
1562                         if ((i & 0x0f) == 0x0f) fprintf(fr_log_fp, "\n");
1563                 }
1564                 fprintf(fr_log_fp, "\n");
1565         }
1566
1567         return 0;
1568 }
1569
1570 int fr_dhcp_add_arp_entry(int fd, const char *interface,
1571                           VALUE_PAIR *macaddr, VALUE_PAIR *ip)
1572 {
1573 #ifdef SIOCSARP
1574         struct sockaddr_in *sin;
1575         struct arpreq req;
1576
1577         if (macaddr->length > sizeof (req.arp_ha.sa_data)) {
1578                 fr_strerror_printf("ERROR: DHCP only supports up to %zu octets "
1579                                    "for Client Hardware Address "
1580                                    "(got %zu octets)\n",
1581                                    sizeof(req.arp_ha.sa_data),
1582                                    macaddr->length);
1583                 return -1;
1584         }
1585
1586         memset(&req, 0, sizeof(req));
1587         sin = (struct sockaddr_in *) &req.arp_pa;
1588         sin->sin_family = AF_INET;
1589         sin->sin_addr.s_addr = ip->vp_ipaddr;
1590         strlcpy(req.arp_dev, interface, sizeof(req.arp_dev));
1591         memcpy(&req.arp_ha.sa_data, macaddr->vp_octets, macaddr->length);
1592
1593         req.arp_flags = ATF_COM;
1594         if (ioctl(fd, SIOCSARP, &req) < 0) {
1595                 fr_strerror_printf("DHCP: Failed to add entry in ARP cache: %s (%d)",
1596                                    strerror(errno), errno);
1597                 return -1;
1598         }
1599
1600         return 0;
1601 #else
1602         fd = fd;                /* -Wunused */
1603         interface = interface;  /* -Wunused */
1604         macaddr = macaddr;      /* -Wunused */
1605         ip = ip;                /* -Wunused */
1606
1607         fr_strerror_printf("Adding ARP entry is unsupported on this system");
1608         return -1;
1609 #endif
1610 }
1611
1612 #endif /* WITH_DHCP */