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 #define DHCP_CHADDR_LEN (16)
  38 #define DHCP_SNAME_LEN  (64)
  39 #define DHCP_FILE_LEN   (128)
  40 #define DHCP_VEND_LEN   (308)
  41 #define DHCP_OPTION_MAGIC_NUMBER (0x63825363)
  42
  43 #ifndef INADDR_BROADCAST
  44 #define INADDR_BROADCAST INADDR_NONE
  45 #endif
  46
  47 typedef struct dhcp_packet_t {
  48         uint8_t         opcode;
  49         uint8_t         htype;
  50         uint8_t         hlen;
  51         uint8_t         hops;
  52         uint32_t        xid;    /* 4 */
  53         uint16_t        secs;   /* 8 */
  54         uint16_t        flags;
  55         uint32_t        ciaddr; /* 12 */
  56         uint32_t        yiaddr; /* 16 */
  57         uint32_t        siaddr; /* 20 */
  58         uint32_t        giaddr; /* 24 */
  59         uint8_t         chaddr[DHCP_CHADDR_LEN]; /* 28 */
  60         uint8_t         sname[DHCP_SNAME_LEN]; /* 44 */
  61         uint8_t         file[DHCP_FILE_LEN]; /* 108 */
  62         uint32_t        option_format; /* 236 */
  63         uint8_t         options[DHCP_VEND_LEN];
  64 } dhcp_packet_t;
  65
  66 typedef struct dhcp_option_t {
  67         uint8_t         code;
  68         uint8_t         length;
  69 } dhcp_option_t;
  70
  71 /*
  72  *      INADDR_ANY : 68 -> INADDR_BROADCAST : 67        DISCOVER
  73  *      INADDR_BROADCAST : 68 <- SERVER_IP : 67         OFFER
  74  *      INADDR_ANY : 68 -> INADDR_BROADCAST : 67        REQUEST
  75  *      INADDR_BROADCAST : 68 <- SERVER_IP : 67         ACK
  76  */
  77 static const char *dhcp_header_names[] = {
  78         "DHCP-Opcode",
  79         "DHCP-Hardware-Type",
  80         "DHCP-Hardware-Address-Length",
  81         "DHCP-Hop-Count",
  82         "DHCP-Transaction-Id",
  83         "DHCP-Number-of-Seconds",
  84         "DHCP-Flags",
  85         "DHCP-Client-IP-Address",
  86         "DHCP-Your-IP-Address",
  87         "DHCP-Server-IP-Address",
  88         "DHCP-Gateway-IP-Address",
  89         "DHCP-Client-Hardware-Address",
  90         "DHCP-Server-Host-Name",
  91         "DHCP-Boot-Filename",
  92
  93         NULL
  94 };
  95
  96 static const char *dhcp_message_types[] = {
  97         "invalid",
  98         "DHCP-Discover",
  99         "DHCP-Offer",
 100         "DHCP-Request",
 101         "DHCP-Decline",
 102         "DHCP-Ack",
 103         "DHCP-NAK",
 104         "DHCP-Release",
 105         "DHCP-Inform",
 106         "DHCP-Force-Renew",
 107 };
 108
 109 static int dhcp_header_sizes[] = {
 110         1, 1, 1, 1,
 111         4, 2, 2, 4,
 112         4, 4, 4,
 113         DHCP_CHADDR_LEN,
 114         DHCP_SNAME_LEN,
 115         DHCP_FILE_LEN
 116 };
 117
 118
 119 /*
 120  *      Some clients silently ignore responses less than 300 bytes.
 121  */
 122 #define MIN_PACKET_SIZE (244)
 123 #define DEFAULT_PACKET_SIZE (300)
 124 #define MAX_PACKET_SIZE (1500 - 40)
 125
 126 #define DHCP_OPTION_FIELD (0)
 127 #define DHCP_FILE_FIELD   (1)
 128 #define DHCP_SNAME_FIELD  (2)
 129
 130 static uint8_t *dhcp_get_option(dhcp_packet_t *packet, size_t packet_size,
 131                                 unsigned int option)
 132
 133 {
 134         int overload = 0;
 135         int field = DHCP_OPTION_FIELD;
 136         size_t where, size;
 137         uint8_t *data = packet->options;
 138
 139         where = 0;
 140         size = packet_size - offsetof(dhcp_packet_t, options);
 141         data = &packet->options[where];
 142
 143         while (where < size) {
 144                 if (data[0] == 0) { /* padding */
 145                         where++;
 146                         continue;
 147                 }
 148
 149                 if (data[0] == 255) { /* end of options */
 150                         if ((field == DHCP_OPTION_FIELD) &&
 151                             (overload & DHCP_FILE_FIELD)) {
 152                                 data = packet->file;
 153                                 where = 0;
 154                                 size = sizeof(packet->file);
 155                                 field = DHCP_FILE_FIELD;
 156                                 continue;
 157
 158                         } else if ((field == DHCP_FILE_FIELD) &&
 159                                    (overload && DHCP_SNAME_FIELD)) {
 160                                 data = packet->sname;
 161                                 where = 0;
 162                                 size = sizeof(packet->sname);
 163                                 field = DHCP_SNAME_FIELD;
 164                                 continue;
 165                         }
 166
 167                         return NULL;
 168                 }
 169
 170                 /*
 171                  *      We MUST have a real option here.
 172                  */
 173                 if ((where + 2) > size) {
 174                         fr_strerror_printf("Options overflow field at %u",
 175                                            (unsigned int) (data - (uint8_t *) packet));
 176                         return NULL;
 177                 }
 178
 179                 if ((where + 2 + data[1]) > size) {
 180                         fr_strerror_printf("Option length overflows field at %u",
 181                                            (unsigned int) (data - (uint8_t *) packet));
 182                         return NULL;
 183                 }
 184
 185                 if (data[0] == option) return data;
 186
 187                 if (data[0] == 52) { /* overload sname and/or file */
 188                         overload = data[3];
 189                 }
 190
 191                 where += data[1] + 2;
 192                 data += data[1] + 2;
 193         }
 194
 195         return NULL;
 196 }
 197
 198 /*
 199  *      DHCPv4 is only for IPv4.  Broadcast only works if udpfromto is
 200  *      defined.
 201  */
 202 RADIUS_PACKET *fr_dhcp_recv(int sockfd)
 203 {
 204         uint32_t                magic;
 205         struct sockaddr_storage src;
 206         struct sockaddr_storage dst;
 207         socklen_t               sizeof_src;
 208         socklen_t               sizeof_dst;
 209         RADIUS_PACKET           *packet;
 210         int port;
 211         uint8_t                 *code;
 212
 213         packet = rad_alloc(0);
 214         if (!packet) {
 215                 fr_strerror_printf("Failed allocating packet");
 216                 return NULL;
 217         }
 218         memset(packet, 0, sizeof(packet));
 219
 220         packet->data = malloc(MAX_PACKET_SIZE);
 221         if (!packet->data) {
 222                 fr_strerror_printf("Failed in malloc");
 223                 rad_free(&packet);
 224                 return NULL;
 225         }
 226
 227         packet->sockfd = sockfd;
 228         sizeof_src = sizeof(src);
 229 #ifdef WITH_UDPFROMTO
 230         sizeof_dst = sizeof(dst);
 231         packet->data_len = recvfromto(sockfd, packet->data, MAX_PACKET_SIZE, 0,
 232                                       (struct sockaddr *)&src, &sizeof_src,
 233                                       (struct sockaddr *)&dst, &sizeof_dst);
 234 #else
 235         packet->data_len = recvfrom(sockfd, packet->data, MAX_PACKET_SIZE, 0,
 236                                     (struct sockaddr *)&src, &sizeof_src);
 237 #endif
 238
 239         if (packet->data_len <= 0) {
 240                 fr_strerror_printf("Failed reading DHCP socket: %s", strerror(errno));
 241                 rad_free(&packet);
 242                 return NULL;
 243         }
 244
 245         if (packet->data_len < MIN_PACKET_SIZE) {
 246                 fr_strerror_printf("DHCP packet is too small (%d < %d)",
 247                                    (int) packet->data_len, MIN_PACKET_SIZE);
 248                 rad_free(&packet);
 249                 return NULL;
 250         }
 251
 252         if (packet->data[1] != 1) {
 253                 fr_strerror_printf("DHCP can only receive ethernet requests, not type %02x",
 254                       packet->data[1]);
 255                 rad_free(&packet);
 256                 return NULL;
 257         }
 258
 259         if (packet->data[2] != 6) {
 260                 fr_strerror_printf("Ethernet HW length is wrong length %d",
 261                         packet->data[2]);
 262                 rad_free(&packet);
 263                 return NULL;
 264         }
 265
 266         memcpy(&magic, packet->data + 236, 4);
 267         magic = ntohl(magic);
 268         if (magic != DHCP_OPTION_MAGIC_NUMBER) {
 269                 fr_strerror_printf("Cannot do BOOTP");
 270                 rad_free(&packet);
 271                 return NULL;
 272         }
 273
 274         /*
 275          *      Create unique keys for the packet.
 276          */
 277         memcpy(&magic, packet->data + 4, 4);
 278         packet->id = ntohl(magic);
 279
 280         code = dhcp_get_option((dhcp_packet_t *) packet->data,
 281                                packet->data_len, 53);
 282         if (!code) {
 283                 fr_strerror_printf("No message-type option was found in the packet");
 284                 rad_free(&packet);
 285                 return NULL;
 286         }
 287
 288         if ((code[1] < 1) || (code[2] == 0) || (code[2] > 8)) {
 289                 fr_strerror_printf("Unknown value for message-type option");
 290                 rad_free(&packet);
 291                 return NULL;
 292         }
 293
 294         packet->code = code[2] | PW_DHCP_OFFSET;
 295
 296         /*
 297          *      Create a unique vector from the MAC address and the
 298          *      DHCP opcode.  This is a hack for the RADIUS
 299          *      infrastructure in the rest of the server.
 300          *
 301          *      Note: packet->data[2] == 6, which is smaller than
 302          *      sizeof(packet->vector)
 303          *
 304          *      FIXME:  Look for client-identifier in packet,
 305          *      and use that, too?
 306          */
 307         memset(packet->vector, 0, sizeof(packet->vector));
 308         memcpy(packet->vector, packet->data + 28, packet->data[2]);
 309         packet->vector[packet->data[2]] = packet->code & 0xff;
 310
 311         /*
 312          *      FIXME: for DISCOVER / REQUEST: src_port == dst_port + 1
 313          *      FIXME: for OFFER / ACK       : src_port = dst_port - 1
 314          */
 315
 316         /*
 317          *      Unique keys are xid, client mac, and client ID?
 318          */
 319
 320         /*
 321          *      FIXME: More checks, like DHCP packet type?
 322          */
 323
 324         sizeof_dst = sizeof(dst);
 325
 326 #ifndef WITH_UDPFROMTO
 327         /*
 328          *      This should never fail...
 329          */
 330         getsockname(sockfd, (struct sockaddr *) &dst, &sizeof_dst);
 331 #endif
 332
 333         fr_sockaddr2ipaddr(&dst, sizeof_dst, &packet->dst_ipaddr, &port);
 334         packet->dst_port = port;
 335
 336         fr_sockaddr2ipaddr(&src, sizeof_src, &packet->src_ipaddr, &port);
 337         packet->src_port = port;
 338
 339         if (fr_debug_flag > 1) {
 340                 char type_buf[64];
 341                 const char *name = type_buf;
 342                 char src_ip_buf[256], dst_ip_buf[256];
 343
 344                 if ((packet->code >= PW_DHCP_DISCOVER) &&
 345                     (packet->code <= PW_DHCP_INFORM)) {
 346                         name = dhcp_message_types[packet->code - PW_DHCP_OFFSET];
 347                 } else {
 348                         snprintf(type_buf, sizeof(type_buf), "%d",
 349                                  packet->code - PW_DHCP_OFFSET);
 350                 }
 351
 352                 DEBUG("Received %s of id %08x from %s:%d to %s:%d\n",
 353                        name, (unsigned int) packet->id,
 354                        inet_ntop(packet->src_ipaddr.af,
 355                                  &packet->src_ipaddr.ipaddr,
 356                                  src_ip_buf, sizeof(src_ip_buf)),
 357                        packet->src_port,
 358                        inet_ntop(packet->dst_ipaddr.af,
 359                                  &packet->dst_ipaddr.ipaddr,
 360                                  dst_ip_buf, sizeof(dst_ip_buf)),
 361                        packet->dst_port);
 362         }
 363
 364         return packet;
 365 }
 366
 367
 368 /*
 369  *      Send a DHCP packet.
 370  */
 371 int fr_dhcp_send(RADIUS_PACKET *packet)
 372 {
 373         struct sockaddr_storage dst;
 374         socklen_t               sizeof_dst;
 375 #ifdef WITH_UDPFROMTO
 376         struct sockaddr_storage src;
 377         socklen_t               sizeof_src;
 378 #endif
 379
 380         fr_ipaddr2sockaddr(&packet->dst_ipaddr, packet->dst_port,
 381                            &dst, &sizeof_dst);
 382
 383         /*
 384          *      The client doesn't yet have an IP address, but is
 385          *      expecting an ethernet packet unicast to it's MAC
 386          *      address.  We need to build a raw frame.
 387          */
 388         if (packet->offset == 0) {
 389                 /*
 390                  *      FIXME: Insert code here!
 391                  */
 392         }
 393
 394 #ifndef WITH_UDPFROMTO
 395         /*
 396          *      Assume that the packet is encoded before sending it.
 397          */
 398         return sendto(packet->sockfd, packet->data, packet->data_len, 0,
 399                       (struct sockaddr *)&dst, sizeof_dst);
 400 #else
 401         fr_ipaddr2sockaddr(&packet->src_ipaddr, packet->src_port,
 402                            &src, &sizeof_src);
 403
 404         return sendfromto(packet->sockfd,
 405                           packet->data, packet->data_len, 0,
 406                           (struct sockaddr *)&src, sizeof_src,
 407                           (struct sockaddr *)&dst, sizeof_dst);
 408 #endif
 409 }
 410
 411 static int fr_dhcp_attr2vp(VALUE_PAIR *vp, const uint8_t *p, size_t alen);
 412
 413 static int decode_tlv(VALUE_PAIR *tlv, const uint8_t *data, size_t data_len)
 414 {
 415         const uint8_t *p;
 416         VALUE_PAIR *head, **tail, *vp;
 417
 418         /*
 419          *      Take a pass at parsing it.
 420          */
 421         p = data;
 422         while (p < (data + data_len)) {
 423                 if ((p + 2) > (data + data_len)) goto make_tlv;
 424
 425                 if ((p + p[1] + 2) > (data + data_len)) goto make_tlv;
 426                 p += 2 + p[1];
 427         }
 428
 429         /*
 430          *      Got here... must be well formed.
 431          */
 432         head = NULL;
 433         tail = &head;
 434
 435         p = data;
 436         while (p < (data + data_len)) {
 437                 vp = paircreate(tlv->attribute | (p[0] << 8), DHCP_MAGIC_VENDOR, PW_TYPE_OCTETS);
 438                 if (!vp) {
 439                         pairfree(&head);
 440                         goto make_tlv;
 441                 }
 442
 443                 if (fr_dhcp_attr2vp(vp, p + 2, p[1]) < 0) {
 444                         pairfree(&head);
 445                         goto make_tlv;
 446                 }
 447
 448                 *tail = vp;
 449                 tail = &(vp->next);
 450                 p += 2 + p[1];
 451         }
 452
 453         /*
 454          *      The caller allocated TLV, so we need to copy the FIRST
 455          *      attribute over top of that.
 456          */
 457         if (head) {
 458                 memcpy(tlv, head, sizeof(*tlv));
 459                 head->next = NULL;
 460                 pairfree(&head);
 461         }
 462
 463         return 0;
 464
 465 make_tlv:
 466         tlv->vp_tlv = malloc(data_len);
 467         if (!tlv->vp_tlv) {
 468                 fr_strerror_printf("No memory");
 469                 return -1;
 470         }
 471         memcpy(tlv->vp_tlv, data, data_len);
 472         tlv->length = data_len;
 473
 474         return 0;
 475 }
 476
 477
 478 /*
 479  *      Decode ONE value into a VP
 480  */
 481 static int fr_dhcp_attr2vp(VALUE_PAIR *vp, const uint8_t *p, size_t alen)
 482 {
 483         switch (vp->type) {
 484         case PW_TYPE_BYTE:
 485                 if (alen != 1) goto raw;
 486                 vp->vp_integer = p[0];
 487                 break;
 488
 489         case PW_TYPE_SHORT:
 490                 if (alen != 2) goto raw;
 491                 vp->vp_integer = (p[0] << 8) | p[1];
 492                 break;
 493
 494         case PW_TYPE_INTEGER:
 495                 if (alen != 4) goto raw;
 496                 memcpy(&vp->vp_integer, p, 4);
 497                 vp->vp_integer = ntohl(vp->vp_integer);
 498                 break;
 499
 500         case PW_TYPE_IPADDR:
 501                 if (alen != 4) goto raw;
 502                 memcpy(&vp->vp_ipaddr, p , 4);
 503                 vp->length = 4;
 504                 break;
 505
 506         case PW_TYPE_STRING:
 507                 if (alen > 253) return -1;
 508                 memcpy(vp->vp_strvalue, p , alen);
 509                 vp->vp_strvalue[alen] = '\0';
 510                 break;
 511
 512         raw:
 513                 vp->type = PW_TYPE_OCTETS;
 514
 515         case PW_TYPE_OCTETS:
 516                 if (alen > 253) return -1;
 517                 memcpy(vp->vp_octets, p, alen);
 518                 break;
 519
 520         case PW_TYPE_TLV:
 521                 return decode_tlv(vp, p, alen);
 522
 523         default:
 524                 fr_strerror_printf("Internal sanity check %d %d", vp->type, __LINE__);
 525                 return -1;
 526         } /* switch over type */
 527
 528         vp->length = alen;
 529         return 0;
 530 }
 531
 532 int fr_dhcp_decode(RADIUS_PACKET *packet)
 533 {
 534         int i;
 535         uint8_t *p, *next;
 536         uint32_t giaddr;
 537         VALUE_PAIR *head, *vp, **tail;
 538         VALUE_PAIR *maxms, *mtu;
 539
 540         head = NULL;
 541         tail = &head;
 542         p = packet->data;
 543
 544         if ((fr_debug_flag > 2) && fr_log_fp) {
 545                 for (i = 0; i < packet->data_len; i++) {
 546                         if ((i & 0x0f) == 0x00) fr_strerror_printf("%d: ", i);
 547                         fprintf(fr_log_fp, "%02x ", packet->data[i]);
 548                         if ((i & 0x0f) == 0x0f) fprintf(fr_log_fp, "\n");
 549                 }
 550                 fprintf(fr_log_fp, "\n");
 551         }
 552
 553         if (packet->data[1] != 1) {
 554                 fr_strerror_printf("Packet is not Ethernet: %u",
 555                       packet->data[1]);
 556                 return -1;
 557         }
 558
 559         /*
 560          *      Decode the header.
 561          */
 562         for (i = 0; i < 14; i++) {
 563                 vp = pairmake(dhcp_header_names[i], NULL, T_OP_EQ);
 564                 if (!vp) {
 565                         fr_strerror_printf("Parse error %s", fr_strerror());
 566                         pairfree(&head);
 567                         return -1;
 568                 }
 569
 570                 if ((i == 11) &&
 571                     (packet->data[1] == 1) &&
 572                     (packet->data[2] == 6)) {
 573                         vp->type = PW_TYPE_ETHERNET;
 574                 }
 575
 576                 switch (vp->type) {
 577                 case PW_TYPE_BYTE:
 578                         vp->vp_integer = p[0];
 579                         vp->length = 1;
 580                         break;
 581
 582                 case PW_TYPE_SHORT:
 583                         vp->vp_integer = (p[0] << 8) | p[1];
 584                         vp->length = 2;
 585                         break;
 586
 587                 case PW_TYPE_INTEGER:
 588                         memcpy(&vp->vp_integer, p, 4);
 589                         vp->vp_integer = ntohl(vp->vp_integer);
 590                         vp->length = 4;
 591                         break;
 592
 593                 case PW_TYPE_IPADDR:
 594                         memcpy(&vp->vp_ipaddr, p, 4);
 595                         vp->length = 4;
 596                         break;
 597
 598                 case PW_TYPE_STRING:
 599                         memcpy(vp->vp_strvalue, p, dhcp_header_sizes[i]);
 600                         vp->vp_strvalue[dhcp_header_sizes[i]] = '\0';
 601                         vp->length = strlen(vp->vp_strvalue);
 602                         if (vp->length == 0) {
 603                                 pairfree(&vp);
 604                         }
 605                         break;
 606
 607                 case PW_TYPE_OCTETS:
 608                         memcpy(vp->vp_octets, p, packet->data[2]);
 609                         vp->length = packet->data[2];
 610                         break;
 611
 612                 case PW_TYPE_ETHERNET:
 613                         memcpy(vp->vp_ether, p, sizeof(vp->vp_ether));
 614                         vp->length = sizeof(vp->vp_ether);
 615                         break;
 616
 617                 default:
 618                         fr_strerror_printf("BAD TYPE %d", vp->type);
 619                         pairfree(&vp);
 620                         break;
 621                 }
 622                 p += dhcp_header_sizes[i];
 623
 624                 if (!vp) continue;
 625
 626                 debug_pair(vp);
 627                 *tail = vp;
 628                 tail = &vp->next;
 629         }
 630
 631         /*
 632          *      Loop over the options.
 633          */
 634         next = packet->data + 240;
 635
 636         /*
 637          *      FIXME: This should also check sname && file fields.
 638          *      See the dhcp_get_option() function above.
 639          */
 640         while (next < (packet->data + packet->data_len)) {
 641                 int num_entries, alen;
 642                 DICT_ATTR *da;
 643
 644                 p = next;
 645
 646                 if (*p == 0) break;
 647                 if (*p == 255) break; /* end of options signifier */
 648                 if ((p + 2) > (packet->data + packet->data_len)) break;
 649
 650                 next = p + 2 + p[1];
 651
 652                 if (p[1] >= 253) {
 653                         fr_strerror_printf("Attribute too long %u %u",
 654                               p[0], p[1]);
 655                         continue;
 656                 }
 657
 658                 da = dict_attrbyvalue(p[0], DHCP_MAGIC_VENDOR);
 659                 if (!da) {
 660                         fr_strerror_printf("Attribute not in our dictionary: %u",
 661                               p[0]);
 662                         continue;
 663                 }
 664
 665                 vp = NULL;
 666                 num_entries = 1;
 667                 alen = p[1];
 668                 p += 2;
 669
 670                 /*
 671                  *      Could be an array of bytes, integers, etc.
 672                  */
 673                 if (da->flags.array) {
 674                         switch (da->type) {
 675                         case PW_TYPE_BYTE:
 676                                 num_entries = alen;
 677                                 alen = 1;
 678                                 break;
 679
 680                         case PW_TYPE_SHORT: /* ignore any trailing data */
 681                                 num_entries = alen >> 1;
 682                                 alen = 2;
 683                                 break;
 684
 685                         case PW_TYPE_IPADDR:
 686                         case PW_TYPE_INTEGER:
 687                         case PW_TYPE_DATE: /* ignore any trailing data */
 688                                 num_entries = alen >> 2;
 689                                 alen = 4;
 690                                 break;
 691
 692                         default:
 693
 694                                 break; /* really an internal sanity failure */
 695                         }
 696                 }
 697
 698                 /*
 699                  *      Loop over all of the entries, building VPs
 700                  */
 701                 for (i = 0; i < num_entries; i++) {
 702                         vp = pairmake(da->name, NULL, T_OP_EQ);
 703                         if (!vp) {
 704                                 fr_strerror_printf("Cannot build attribute %s",
 705                                         fr_strerror());
 706                                 pairfree(&head);
 707                                 return -1;
 708                         }
 709
 710                         /*
 711                          *      Hack for ease of use.
 712                          */
 713                         if ((da->attr == 0x3d) &&
 714                             !da->flags.array &&
 715                             (alen == 7) && (*p == 1) && (num_entries == 1)) {
 716                                 vp->type = PW_TYPE_ETHERNET;
 717                                 memcpy(vp->vp_octets, p + 1, 6);
 718                                 vp->length = alen;
 719
 720                         } else if (fr_dhcp_attr2vp(vp, p, alen) < 0) {
 721                                         pairfree(&vp);
 722                                         pairfree(&head);
 723                                         return -1;
 724                         }
 725
 726                         *tail = vp;
 727                         while (*tail) {
 728                                 debug_pair(*tail);
 729                                 tail = &(*tail)->next;
 730                         }
 731                         p += alen;
 732                 } /* loop over array entries */
 733         } /* loop over the entire packet */
 734
 735         /*
 736          *      If DHCP request, set ciaddr to zero.
 737          */
 738
 739         /*
 740          *      Set broadcast flag for broken vendors, but only if
 741          *      giaddr isn't set.
 742          */
 743         memcpy(&giaddr, packet->data + 24, sizeof(giaddr));
 744         if (giaddr == htonl(INADDR_ANY)) {
 745                 /*
 746                  *      DHCP Opcode is request
 747                  */
 748                 vp = pairfind(head, 256, DHCP_MAGIC_VENDOR);
 749                 if (vp && vp->vp_integer == 3) {
 750                         /*
 751                          *      Vendor is "MSFT 98"
 752                          */
 753                         vp = pairfind(head, 63, DHCP_MAGIC_VENDOR);
 754                         if (vp && (strcmp(vp->vp_strvalue, "MSFT 98") == 0)) {
 755                                 vp = pairfind(head, 262, DHCP_MAGIC_VENDOR);
 756
 757                                 /*
 758                                  *      Reply should be broadcast.
 759                                  */
 760                                 if (vp) vp->vp_integer |= 0x8000;
 761                                 packet->data[10] |= 0x80;
 762                         }
 763                 }
 764         }
 765
 766         /*
 767          *      FIXME: Nuke attributes that aren't used in the normal
 768          *      header for discover/requests.
 769          */
 770         packet->vps = head;
 771
 772         /*
 773          *      Client can request a LARGER size, but not a smaller
 774          *      one.  They also cannot request a size larger than MTU.
 775          */
 776         maxms = pairfind(packet->vps, 57, DHCP_MAGIC_VENDOR);
 777         mtu = pairfind(packet->vps, 26, DHCP_MAGIC_VENDOR);
 778
 779         if (mtu && (mtu->vp_integer < DEFAULT_PACKET_SIZE)) {
 780                 fr_strerror_printf("DHCP Fatal: Client says MTU is smaller than minimum permitted by the specification.");
 781                 return -1;
 782         }
 783
 784         if (maxms && (maxms->vp_integer < DEFAULT_PACKET_SIZE)) {
 785                 fr_strerror_printf("DHCP WARNING: Client says maximum message size is smaller than minimum permitted by the specification: fixing it");
 786                 maxms->vp_integer = DEFAULT_PACKET_SIZE;
 787         }
 788
 789         if (maxms && mtu && (maxms->vp_integer > mtu->vp_integer)) {
 790                 fr_strerror_printf("DHCP WARNING: Client says MTU is smaller than maximum message size: fixing it");
 791                 maxms->vp_integer = mtu->vp_integer;
 792         }
 793
 794         if (fr_debug_flag > 0) {
 795                 for (vp = packet->vps; vp != NULL; vp = vp->next) {
 796
 797                 }
 798         }
 799
 800         if (fr_debug_flag) fflush(stdout);
 801
 802         return 0;
 803 }
 804
 805
 806 static int attr_cmp(const void *one, const void *two)
 807 {
 808         const VALUE_PAIR * const *a = one;
 809         const VALUE_PAIR * const *b = two;
 810
 811         /*
 812          *      DHCP-Message-Type is first, for simplicity.
 813          */
 814         if (((*a)->attribute == 53) &&
 815             (*b)->attribute != 53) return -1;
 816
 817         /*
 818          *      Relay-Agent is last
 819          */
 820         if (((*a)->attribute == 82) &&
 821             (*b)->attribute != 82) return +1;
 822
 823         return ((*a)->attribute - (*b)->attribute);
 824 }
 825
 826
 827 static size_t fr_dhcp_vp2attr(VALUE_PAIR *vp, uint8_t *p, size_t room)
 828 {
 829         size_t length;
 830         uint32_t lvalue;
 831
 832         /*
 833          *      FIXME: Check room!
 834          */
 835         room = room;            /* -Wunused */
 836
 837         /*
 838          *      Search for all attributes of the same
 839          *      type, and pack them into the same
 840          *      attribute.
 841          */
 842         switch (vp->type) {
 843         case PW_TYPE_BYTE:
 844                 length = 1;
 845                 *p = vp->vp_integer & 0xff;
 846                 break;
 847
 848         case PW_TYPE_SHORT:
 849                 length = 2;
 850                 p[0] = (vp->vp_integer >> 8) & 0xff;
 851                 p[1] = vp->vp_integer & 0xff;
 852                 break;
 853
 854         case PW_TYPE_INTEGER:
 855                 length = 4;
 856                 lvalue = htonl(vp->vp_integer);
 857                 memcpy(p, &lvalue, 4);
 858                 break;
 859
 860         case PW_TYPE_IPADDR:
 861                 length = 4;
 862                 memcpy(p, &vp->vp_ipaddr, 4);
 863                 break;
 864
 865         case PW_TYPE_ETHERNET:
 866                 length = 6;
 867                 memcpy(p, &vp->vp_ether, 6);
 868                 break;
 869
 870         case PW_TYPE_STRING:
 871                 memcpy(p, vp->vp_strvalue, vp->length);
 872                 length = vp->length;
 873                 break;
 874
 875         case PW_TYPE_TLV:       /* FIXME: split it on 255? */
 876                 memcpy(p, vp->vp_tlv, vp->length);
 877                 length = vp->length;
 878                 break;
 879
 880         case PW_TYPE_OCTETS:
 881                 memcpy(p, vp->vp_octets, vp->length);
 882                 length = vp->length;
 883                 break;
 884
 885         default:
 886                 fr_strerror_printf("BAD TYPE2 %d", vp->type);
 887                 length = 0;
 888                 break;
 889         }
 890
 891         return length;
 892 }
 893
 894 static VALUE_PAIR *fr_dhcp_vp2suboption(VALUE_PAIR *vps)
 895 {
 896         int length;
 897         unsigned int attribute;
 898         uint8_t *ptr;
 899         VALUE_PAIR *vp, *tlv;
 900
 901         attribute = vps->attribute & 0xffff00ff;
 902
 903         tlv = paircreate(attribute, DHCP_MAGIC_VENDOR, PW_TYPE_TLV);
 904         if (!tlv) return NULL;
 905
 906         tlv->length = 0;
 907         for (vp = vps; vp != NULL; vp = vp->next) {
 908                 /*
 909                  *      Group the attributes ONLY until we see a
 910                  *      non-TLV attribute.
 911                  */
 912                 if (!vp->flags.is_tlv ||
 913                     vp->flags.extended ||
 914                     ((vp->attribute & 0xffff00ff) != attribute)) {
 915                         break;
 916                 }
 917
 918                 tlv->length += vp->length + 2;
 919         }
 920
 921         if (!tlv->length) {
 922                 pairfree(&tlv);
 923                 return NULL;
 924         }
 925
 926         tlv->vp_tlv = malloc(tlv->length);
 927         if (!tlv->vp_tlv) {
 928                 pairfree(&tlv);
 929                 return NULL;
 930         }
 931
 932         ptr = tlv->vp_tlv;
 933         for (vp = vps; vp != NULL; vp = vp->next) {
 934                 if (!vp->flags.is_tlv ||
 935                     vp->flags.extended ||
 936                     ((vp->attribute & 0xffff00ff) != attribute)) {
 937                         break;
 938                 }
 939
 940                 length = fr_dhcp_vp2attr(vp, ptr + 2,
 941                                          tlv->vp_tlv + tlv->length - ptr);
 942                 if (length > 255) return NULL;
 943
 944                 /*
 945                  *      Pack the attribute.
 946                  */
 947                 ptr[0] = (vp->attribute & 0xff00) >> 8;
 948                 ptr[1] = length;
 949
 950                 ptr += length + 2;
 951                 vp->flags.extended = 1;
 952         }
 953
 954         return tlv;
 955 }
 956
 957
 958 int fr_dhcp_encode(RADIUS_PACKET *packet, RADIUS_PACKET *original)
 959 {
 960         int i, num_vps;
 961         uint8_t *p;
 962         VALUE_PAIR *vp;
 963         uint32_t lvalue, mms;
 964         size_t dhcp_size, length;
 965         dhcp_packet_t *dhcp;
 966         char buffer[1024];
 967
 968         if (packet->data) return 0;
 969
 970         packet->data = malloc(MAX_PACKET_SIZE);
 971         if (!packet->data) return -1;
 972
 973         packet->data_len = MAX_PACKET_SIZE;
 974
 975         if (packet->code == 0) packet->code = PW_DHCP_NAK;
 976
 977         /*
 978          *      If there's a request, use it as a template.
 979          *      Otherwise, assume that the caller has set up
 980          *      everything appropriately.
 981          */
 982         if (original) {
 983                 packet->dst_ipaddr.af = AF_INET;
 984                 packet->src_ipaddr.af = AF_INET;
 985
 986                 packet->dst_port = original->src_port;
 987                 packet->src_port = original->dst_port;
 988
 989                 /*
 990                  *      Note that for DHCP, we NEVER send the response
 991                  *      to the source IP address of the request.  It
 992                  *      may have traversed multiple relays, and we
 993                  *      need to send the request to the relay closest
 994                  *      to the client.
 995                  *
 996                  *      if giaddr, send to giaddr.
 997                  *      if NAK, send broadcast.
 998                  *      if broadcast flag, send broadcast.
 999                  *      if ciaddr is empty, send broadcast.
1000                  *      otherwise unicast to ciaddr.
1001                  */
1002
1003                 /*
1004                  *      FIXME: alignment issues.  We likely don't want to
1005                  *      de-reference the packet structure directly..
1006                  */
1007                 dhcp = (dhcp_packet_t *) original->data;
1008
1009                 /*
1010                  *      Default to sending it via sendto(), without using
1011                  *      raw sockets.
1012                  */
1013                 packet->offset = 1;
1014
1015                 if (dhcp->giaddr != htonl(INADDR_ANY)) {
1016                         packet->dst_ipaddr.ipaddr.ip4addr.s_addr = dhcp->giaddr;
1017
1018                         if (dhcp->giaddr != htonl(INADDR_LOOPBACK)) {
1019                                 packet->dst_port = original->dst_port;
1020                         } else {
1021                                 packet->dst_port = original->src_port; /* debugging */
1022                         }
1023
1024                 } else if ((packet->code == PW_DHCP_NAK) ||
1025                            ((dhcp->flags & 0x8000) != 0) ||
1026                            (dhcp->ciaddr == htonl(INADDR_ANY))) {
1027                         /*
1028                          *      The kernel will take care of sending it to
1029                          *      the broadcast MAC.
1030                          */
1031                         packet->dst_ipaddr.ipaddr.ip4addr.s_addr = htonl(INADDR_BROADCAST);
1032
1033                 } else {
1034                         /*
1035                          *      It was broadcast to us: we need to
1036                          *      broadcast the response.
1037                          */
1038                         if (packet->src_ipaddr.ipaddr.ip4addr.s_addr != dhcp->ciaddr) {
1039                                 packet->offset = 0;
1040                         }
1041                         packet->dst_ipaddr.ipaddr.ip4addr.s_addr = dhcp->ciaddr;
1042                 }
1043
1044                 /*
1045                  *      Rewrite the source IP to be our own, if we know it.
1046                  */
1047                 if (packet->src_ipaddr.ipaddr.ip4addr.s_addr == htonl(INADDR_BROADCAST)) {
1048                         packet->src_ipaddr.ipaddr.ip4addr.s_addr = htonl(INADDR_ANY);
1049                 }
1050         } else {
1051                 memset(packet->data, 0, packet->data_len);
1052         }
1053
1054         if (fr_debug_flag > 1) {
1055                 char type_buf[64];
1056                 const char *name = type_buf;
1057                 char src_ip_buf[256], dst_ip_buf[256];
1058
1059                 if ((packet->code >= PW_DHCP_DISCOVER) &&
1060                     (packet->code <= PW_DHCP_INFORM)) {
1061                         name = dhcp_message_types[packet->code - PW_DHCP_OFFSET];
1062                 } else {
1063                         snprintf(type_buf, sizeof(type_buf), "%d",
1064                                  packet->code - PW_DHCP_OFFSET);
1065                 }
1066
1067                 DEBUG("Sending %s of id %08x from %s:%d to %s:%d\n",
1068                        name, (unsigned int) packet->id,
1069                        inet_ntop(packet->src_ipaddr.af,
1070                                  &packet->src_ipaddr.ipaddr,
1071                                  src_ip_buf, sizeof(src_ip_buf)),
1072                        packet->src_port,
1073                        inet_ntop(packet->dst_ipaddr.af,
1074                                  &packet->dst_ipaddr.ipaddr,
1075                                  dst_ip_buf, sizeof(dst_ip_buf)),
1076                        packet->dst_port);
1077
1078                 if (fr_debug_flag) {
1079                         for (i = 256; i < 269; i++) {
1080                                 vp = pairfind(packet->vps, i,
1081                                               DHCP_MAGIC_VENDOR);
1082                                 if (!vp) continue;
1083
1084                                 debug_pair(vp);
1085                         }
1086                 }
1087         }
1088
1089         p = packet->data;
1090
1091         mms = DEFAULT_PACKET_SIZE; /* maximum message size */
1092
1093         if (original) {
1094                 /*
1095                  *      Clients can request a LARGER size, but not a
1096                  *      smaller one.  They also cannot request a size
1097                  *      larger than MTU.
1098                  */
1099                 vp = pairfind(original->vps, 57, DHCP_MAGIC_VENDOR);
1100                 if (vp && (vp->vp_integer > mms)) {
1101                         mms = vp->vp_integer;
1102
1103                         if (mms > MAX_PACKET_SIZE) mms = MAX_PACKET_SIZE;
1104                 }
1105         }
1106
1107         /*
1108          *      RFC 3118: Authentication option.
1109          */
1110         vp = pairfind(packet->vps, 90, DHCP_MAGIC_VENDOR);
1111         if (vp) {
1112                 if (vp->length < 2) {
1113                         memset(vp->vp_octets + vp->length, 0,
1114                                2 - vp->length);
1115                         vp->length = 2;
1116                 }
1117
1118                 if (vp->length < 3) {
1119                         struct timeval tv;
1120
1121                         gettimeofday(&tv, NULL);
1122                         vp->vp_octets[2] = 0;
1123                         timeval2ntp(&tv, vp->vp_octets + 3);
1124                         vp->length = 3 + 8;
1125                 }
1126
1127                 /*
1128                  *      Configuration token (clear-text token)
1129                  */
1130                 if (vp->vp_octets[0] == 0) {
1131                         VALUE_PAIR *pass;
1132                         vp->vp_octets[1] = 0;
1133
1134                         pass = pairfind(packet->vps, PW_CLEARTEXT_PASSWORD, DHCP_MAGIC_VENDOR);
1135                         if (pass) {
1136                                 length = pass->length;
1137                                 if ((length + 11) > sizeof(vp->vp_octets)) {
1138                                         length -= ((length + 11) - sizeof(vp->vp_octets));
1139                                 }
1140                                 memcpy(vp->vp_octets + 11, pass->vp_strvalue,
1141                                        length);
1142                                 vp->length = length + 11;
1143                         } else {
1144                                 vp->length = 11 + 8;
1145                                 memset(vp->vp_octets + 11, 0, 8);
1146                                 vp->length = 11 + 8;
1147                         }
1148                 } else {        /* we don't support this type! */
1149                         fr_strerror_printf("DHCP-Authentication %d unsupported",
1150                                 vp->vp_octets[0]);
1151                 }
1152         }
1153
1154         vp = pairfind(packet->vps, 256, DHCP_MAGIC_VENDOR);
1155         if (vp) {
1156                 *p++ = vp->vp_integer & 0xff;
1157         } else {
1158                 if (!original) {
1159                         *p++ = 1;       /* client message */
1160                 } else {
1161                         *p++ = 2;       /* server message */
1162                 }
1163         }
1164         *p++ = 1;               /* hardware type = ethernet */
1165         *p++ = 6;               /* 6 bytes of ethernet */
1166
1167         vp = pairfind(packet->vps, 259, DHCP_MAGIC_VENDOR);
1168         if (vp) {
1169                 *p++ = vp->vp_integer & 0xff;
1170         } else {
1171                 *p++ = 0;               /* hops */
1172         }
1173
1174         if (original) { /* Xid */
1175                 memcpy(p, original->data + 4, 4);
1176         } else {
1177                 lvalue = fr_rand();
1178                 memcpy(p, &lvalue, 4);
1179         }
1180         p += 4;
1181
1182         memset(p, 0, 2);        /* secs are zero */
1183         p += 2;
1184
1185         if (original) {
1186                 memcpy(p, original->data + 10, 6); /* copy flags && ciaddr */
1187         }
1188
1189         /*
1190          *      Allow the admin to set the broadcast flag.
1191          */
1192         vp = pairfind(packet->vps, 262, DHCP_MAGIC_VENDOR);
1193         if (vp) {
1194                 p[0] |= (vp->vp_integer & 0xff00) >> 8;
1195                 p[1] |= (vp->vp_integer & 0xff);
1196         }
1197
1198         p += 6;
1199
1200         /*
1201          *      Set client IP address.
1202          */
1203         vp = pairfind(packet->vps, 264, DHCP_MAGIC_VENDOR); /* Your IP address */
1204         if (vp) {
1205                 lvalue = vp->vp_ipaddr;
1206         } else {
1207                 lvalue = htonl(INADDR_ANY);
1208         }
1209         memcpy(p, &lvalue, 4);  /* your IP address */
1210         p += 4;
1211
1212         vp = pairfind(packet->vps, 265, DHCP_MAGIC_VENDOR); /* server IP address */
1213         if (!vp) vp = pairfind(packet->vps, 54, DHCP_MAGIC_VENDOR); /* identifier */
1214         if (vp) {
1215                 lvalue = vp->vp_ipaddr;
1216         } else {
1217                 lvalue = htonl(INADDR_ANY);
1218         }
1219         memcpy(p, &lvalue, 4);  /* Server IP address */
1220         p += 4;
1221
1222         if (original) {
1223                 memcpy(p, original->data + 24, 4); /* copy gateway IP address */
1224         } else {
1225                 vp = pairfind(packet->vps, 266, DHCP_MAGIC_VENDOR);
1226                 if (vp) {
1227                         lvalue = vp->vp_ipaddr;
1228                 } else {
1229                         lvalue = htonl(INADDR_NONE);
1230                 }
1231                 memcpy(p, &lvalue, 4);
1232         }
1233         p += 4;
1234
1235         if (original) {
1236                 memcpy(p, original->data + 28, DHCP_CHADDR_LEN);
1237         } else {
1238                 vp = pairfind(packet->vps, 267, DHCP_MAGIC_VENDOR);
1239                 if (vp) {
1240                         if (vp->length > DHCP_CHADDR_LEN) {
1241                                 memcpy(p, vp->vp_octets, DHCP_CHADDR_LEN);
1242                         } else {
1243                                 memcpy(p, vp->vp_octets, vp->length);
1244                         }
1245                 }
1246         }
1247         p += DHCP_CHADDR_LEN;
1248
1249         /*
1250          *      Zero our sname && filename fields.
1251          */
1252         memset(p, 0, DHCP_SNAME_LEN + DHCP_FILE_LEN);
1253         p += DHCP_SNAME_LEN;
1254
1255         /*
1256          *      Copy over DHCP-Boot-Filename.
1257          *
1258          *      FIXME: This copy should be delayed until AFTER the options
1259          *      have been processed.  If there are too many options for
1260          *      the packet, then they go into the sname && filename fields.
1261          *      When that happens, the boot filename is passed as an option,
1262          *      instead of being placed verbatim in the filename field.
1263          */
1264         vp = pairfind(packet->vps, 269, DHCP_MAGIC_VENDOR);
1265         if (vp) {
1266                 if (vp->length > DHCP_FILE_LEN) {
1267                         memcpy(p, vp->vp_strvalue, DHCP_FILE_LEN);
1268                 } else {
1269                         memcpy(p, vp->vp_strvalue, vp->length);
1270                 }
1271         }
1272         p += DHCP_FILE_LEN;
1273
1274         lvalue = htonl(DHCP_OPTION_MAGIC_NUMBER); /* DHCP magic number */
1275         memcpy(p, &lvalue, 4);
1276         p += 4;
1277
1278         /*
1279          *      Print the header.
1280          */
1281         if (fr_debug_flag > 1) {
1282                 uint8_t *pp = p;
1283
1284                 p = packet->data;
1285
1286                 for (i = 0; i < 14; i++) {
1287                         vp = pairmake(dhcp_header_names[i], NULL, T_OP_EQ);
1288                         if (!vp) {
1289                                 fr_strerror_printf("Parse error %s", fr_strerror());
1290                                 return -1;
1291                         }
1292
1293                         switch (vp->type) {
1294                         case PW_TYPE_BYTE:
1295                                 vp->vp_integer = p[0];
1296                                 vp->length = 1;
1297                                 break;
1298
1299                         case PW_TYPE_SHORT:
1300                                 vp->vp_integer = (p[0] << 8) | p[1];
1301                                 vp->length = 2;
1302                                 break;
1303
1304                         case PW_TYPE_INTEGER:
1305                                 memcpy(&vp->vp_integer, p, 4);
1306                                 vp->vp_integer = ntohl(vp->vp_integer);
1307                                 vp->length = 4;
1308                                 break;
1309
1310                         case PW_TYPE_IPADDR:
1311                                 memcpy(&vp->vp_ipaddr, p, 4);
1312                                 vp->length = 4;
1313                                 break;
1314
1315                         case PW_TYPE_STRING:
1316                                 memcpy(vp->vp_strvalue, p, dhcp_header_sizes[i]);
1317                                 vp->vp_strvalue[dhcp_header_sizes[i]] = '\0';
1318                                 vp->length = strlen(vp->vp_strvalue);
1319                                 break;
1320
1321                         case PW_TYPE_OCTETS: /* only for Client HW Address */
1322                                 memcpy(vp->vp_octets, p, packet->data[2]);
1323                                 vp->length = packet->data[2];
1324                                 break;
1325
1326                         case PW_TYPE_ETHERNET: /* only for Client HW Address */
1327                                 memcpy(vp->vp_ether, p, sizeof(vp->vp_ether));
1328                                 vp->length = sizeof(vp->vp_ether);
1329                                 break;
1330
1331                         default:
1332                                 fr_strerror_printf("Internal sanity check failed %d %d", vp->type, __LINE__);
1333                                 pairfree(&vp);
1334                                 break;
1335                         }
1336
1337                         p += dhcp_header_sizes[i];
1338
1339                         vp_prints(buffer, sizeof(buffer), vp);
1340                         fr_strerror_printf("\t%s", buffer);
1341                         pairfree(&vp);
1342                 }
1343
1344                 /*
1345                  *      Jump over DHCP magic number, response, etc.
1346                  */
1347                 p = pp;
1348         }
1349
1350         /*
1351          *      Before packing the attributes, re-order them so that
1352          *      the array ones are all contiguous.  This simplifies
1353          *      the later code.
1354          */
1355         num_vps = 0;
1356         for (vp = packet->vps; vp != NULL; vp = vp->next) {
1357                 num_vps++;
1358         }
1359         if (num_vps > 1) {
1360                 VALUE_PAIR **array, **last;
1361
1362                 array = malloc(num_vps * sizeof(VALUE_PAIR *));
1363
1364                 i = 0;
1365                 for (vp = packet->vps; vp != NULL; vp = vp->next) {
1366                         array[i++] = vp;
1367                 }
1368
1369                 /*
1370                  *      Sort the attributes.
1371                  */
1372                 qsort(array, (size_t) num_vps, sizeof(VALUE_PAIR *),
1373                       attr_cmp);
1374
1375                 last = &packet->vps;
1376                 for (i = 0; i < num_vps; i++) {
1377                         *last = array[i];
1378                         array[i]->next = NULL;
1379                         last = &(array[i]->next);
1380                 }
1381                 free(array);
1382         }
1383
1384         p[0] = 0x35;            /* DHCP-Message-Type */
1385         p[1] = 1;
1386         p[2] = packet->code - PW_DHCP_OFFSET;
1387         p += 3;
1388
1389         /*
1390          *      Pack in the attributes.
1391          */
1392         vp = packet->vps;
1393         while (vp) {
1394                 int num_entries = 1;
1395                 VALUE_PAIR *same;
1396                 uint8_t *plength, *pattr;
1397
1398                 if (vp->vendor != DHCP_MAGIC_VENDOR) goto next;
1399                 if (vp->attribute == 53) goto next; /* already done */
1400                 if ((vp->attribute > 255) &&
1401                     (DHCP_BASE_ATTR(vp->attribute) != PW_DHCP_OPTION_82)) goto next;
1402
1403                 debug_pair(vp);
1404                 if (vp->flags.extended) goto next;
1405
1406                 length = vp->length;
1407
1408                 for (same = vp->next; same != NULL; same = same->next) {
1409                         if (same->attribute != vp->attribute) break;
1410                         num_entries++;
1411                 }
1412
1413                 /*
1414                  *      For client-identifier
1415                  */
1416                 if ((vp->type == PW_TYPE_ETHERNET) &&
1417                     (vp->length == 6) &&
1418                     (num_entries == 1)) {
1419                         vp->type = PW_TYPE_OCTETS;
1420                         memmove(vp->vp_octets + 1, vp->vp_octets, 6);
1421                         vp->vp_octets[0] = 1;
1422                 }
1423
1424                 pattr = p;
1425                 *(p++) = vp->attribute & 0xff;
1426                 plength = p;
1427                 *(p++) = 0;     /* header isn't included in attr length */
1428
1429                 for (i = 0; i < num_entries; i++) {
1430                         if (fr_debug_flag > 1) {
1431                                 vp_prints(buffer, sizeof(buffer), vp);
1432                                 fr_strerror_printf("\t%s", buffer);
1433                         }
1434
1435                         if (vp->flags.is_tlv) {
1436                                 VALUE_PAIR *tlv;
1437
1438                                 /*
1439                                  *      Should NOT have been encoded yet!
1440                                  */
1441                                 tlv = fr_dhcp_vp2suboption(vp);
1442
1443                                 /*
1444                                  *      Ignore it if there's an issue
1445                                  *      encoding it.
1446                                  */
1447                                 if (!tlv) goto next;
1448
1449                                 tlv->next = vp->next;
1450                                 vp->next = tlv;
1451                                 vp = tlv;
1452                         }
1453
1454                         length = fr_dhcp_vp2attr(vp, p, 0);
1455
1456                         /*
1457                          *      This will never happen due to FreeRADIUS
1458                          *      limitations: sizeof(vp->vp_octets) < 255
1459                          */
1460                         if (length > 255) {
1461                                 fr_strerror_printf("WARNING Ignoring too long attribute %s!", vp->name);
1462                                 break;
1463                         }
1464
1465                         /*
1466                          *      More than one attribute of the same type
1467                          *      in a row: they are packed together
1468                          *      into the same TLV.  If we overflow,
1469                          *      go bananas!
1470                          */
1471                         if ((*plength + length) > 255) {
1472                                 fr_strerror_printf("WARNING Ignoring too long attribute %s!", vp->name);
1473                                 break;
1474                         }
1475
1476                         *plength += length;
1477                         p += length;
1478
1479                         if (vp->next &&
1480                             (vp->next->attribute == vp->attribute))
1481                                 vp = vp->next;
1482                 } /* loop over num_entries */
1483
1484         next:
1485                 vp = vp->next;
1486         }
1487
1488         p[0] = 0xff;            /* end of option option */
1489         p[1] = 0x00;
1490         p += 2;
1491         dhcp_size = p - packet->data;
1492
1493         /*
1494          *      FIXME: if (dhcp_size > mms),
1495          *        then we put the extra options into the "sname" and "file"
1496          *        fields, AND set the "end option option" in the "options"
1497          *        field.  We also set the "overload option",
1498          *        and put options into the "file" field, followed by
1499          *        the "sname" field.  Where each option is completely
1500          *        enclosed in the "file" and/or "sname" field, AND
1501          *        followed by the "end of option", and MUST be followed
1502          *        by padding option.
1503          *
1504          *      Yuck.  That sucks...
1505          */
1506         packet->data_len = dhcp_size;
1507
1508         if (original) {
1509                 /*
1510                  *      FIXME: This may set it to broadcast, which we don't
1511                  *      want.  Instead, set it to the real address of the
1512                  *      socket.
1513                  */
1514                 packet->src_ipaddr = original->dst_ipaddr;
1515
1516                 packet->sockfd = original->sockfd;
1517         }
1518
1519         if (packet->data_len < DEFAULT_PACKET_SIZE) {
1520                 memset(packet->data + packet->data_len, 0,
1521                        DEFAULT_PACKET_SIZE - packet->data_len);
1522                 packet->data_len = DEFAULT_PACKET_SIZE;
1523         }
1524
1525         if ((fr_debug_flag > 2) && fr_log_fp) {
1526                 for (i = 0; i < packet->data_len; i++) {
1527                         if ((i & 0x0f) == 0x00) fprintf(fr_log_fp, "%d: ", i);
1528                         fprintf(fr_log_fp, "%02x ", packet->data[i]);
1529                         if ((i & 0x0f) == 0x0f) fprintf(fr_log_fp, "\n");
1530                 }
1531                 fprintf(fr_log_fp, "\n");
1532         }
1533
1534         return 0;
1535 }
1536
1537 int fr_dhcp_add_arp_entry(int fd, const char *interface,
1538                           VALUE_PAIR *macaddr, VALUE_PAIR *ip)
1539 {
1540 #ifdef SIOCSARP
1541         struct sockaddr_in *sin
1542         struct arpreq req;
1543
1544         if (macaddr->length > sizeof (req.arp_ha.sa_data)) {
1545                 fr_strerror_printf("ERROR: DHCP only supports up to %d octets for "
1546                                    "Client Hardware Address (got %d octets)\n",
1547                                    sizeof(req.arp_ha.sa_data),
1548                                    macaddr->length);
1549                 return -1;
1550         }
1551
1552         memset(&req, 0, sizeof(req));
1553         sin = (struct sockaddr_in *) &req.arp_pa;
1554         sin->sin_family = AF_INET;
1555         sin->sin_addr.s_addr = ip->vp_ipaddr;
1556         strlcpy(req.arp_dev, interface, sizeof(req.arp_dev));
1557         memcpy(&req.arp_ha.sa_data, macaddr->vp_octets, macaddr->length);
1558
1559         req.arp_flags = ATF_COM;
1560         if (ioctl(fd, SIOCSARP, &req) < 0) {
1561                 fr_strerror_printf("DHCP: Failed to add entry in ARP cache: %s (%d)",
1562                                    strerror(errno), errno);
1563                 return -1;
1564         }
1565
1566         return 0;
1567 #else
1568         fd = fd;                /* -Wunused */
1569         interface = interface;  /* -Wunused */
1570         macaddr = macaddr;      /* -Wunused */
1571         ip = ip;                /* -Wunused */
1572
1573         fr_strerror_printf("Adding ARP entry is unsupported on this system");
1574         return -1;
1575 #endif
1576 }
1577
1578 #endif /* WITH_DHCP */