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         getsockname(sockfd, (struct sockaddr *) &dst, &sizeof_dst);
 344 #endif
 345
 346         fr_sockaddr2ipaddr(&dst, sizeof_dst, &packet->dst_ipaddr, &port);
 347         packet->dst_port = port;
 348
 349         fr_sockaddr2ipaddr(&src, sizeof_src, &packet->src_ipaddr, &port);
 350         packet->src_port = port;
 351
 352         if (fr_debug_flag > 1) {
 353                 char type_buf[64];
 354                 const char *name = type_buf;
 355                 char src_ip_buf[256], dst_ip_buf[256];
 356
 357                 if ((packet->code >= PW_DHCP_DISCOVER) &&
 358                     (packet->code <= PW_DHCP_INFORM)) {
 359                         name = dhcp_message_types[packet->code - PW_DHCP_OFFSET];
 360                 } else {
 361                         snprintf(type_buf, sizeof(type_buf), "%d",
 362                                  packet->code - PW_DHCP_OFFSET);
 363                 }
 364
 365                 DEBUG("Received %s of id %08x from %s:%d to %s:%d\n",
 366                        name, (unsigned int) packet->id,
 367                        inet_ntop(packet->src_ipaddr.af,
 368                                  &packet->src_ipaddr.ipaddr,
 369                                  src_ip_buf, sizeof(src_ip_buf)),
 370                        packet->src_port,
 371                        inet_ntop(packet->dst_ipaddr.af,
 372                                  &packet->dst_ipaddr.ipaddr,
 373                                  dst_ip_buf, sizeof(dst_ip_buf)),
 374                        packet->dst_port);
 375         }
 376
 377         return packet;
 378 }
 379
 380
 381 /*
 382  *      Send a DHCP packet.
 383  */
 384 int fr_dhcp_send(RADIUS_PACKET *packet)
 385 {
 386         struct sockaddr_storage dst;
 387         socklen_t               sizeof_dst;
 388 #ifdef WITH_UDPFROMTO
 389         struct sockaddr_storage src;
 390         socklen_t               sizeof_src;
 391 #endif
 392
 393         fr_ipaddr2sockaddr(&packet->dst_ipaddr, packet->dst_port,
 394                            &dst, &sizeof_dst);
 395
 396         /*
 397          *      The client doesn't yet have an IP address, but is
 398          *      expecting an ethernet packet unicast to it's MAC
 399          *      address.  We need to build a raw frame.
 400          */
 401         if (packet->offset == 0) {
 402                 /*
 403                  *      FIXME: Insert code here!
 404                  */
 405         }
 406
 407 #ifndef WITH_UDPFROMTO
 408         /*
 409          *      Assume that the packet is encoded before sending it.
 410          */
 411         return sendto(packet->sockfd, packet->data, packet->data_len, 0,
 412                       (struct sockaddr *)&dst, sizeof_dst);
 413 #else
 414         fr_ipaddr2sockaddr(&packet->src_ipaddr, packet->src_port,
 415                            &src, &sizeof_src);
 416
 417         return sendfromto(packet->sockfd,
 418                           packet->data, packet->data_len, 0,
 419                           (struct sockaddr *)&src, sizeof_src,
 420                           (struct sockaddr *)&dst, sizeof_dst);
 421 #endif
 422 }
 423
 424 static int fr_dhcp_attr2vp(VALUE_PAIR *vp, const uint8_t *p, size_t alen);
 425
 426 static int decode_tlv(VALUE_PAIR *tlv, const uint8_t *data, size_t data_len)
 427 {
 428         const uint8_t *p;
 429         VALUE_PAIR *head, **tail, *vp;
 430
 431         /*
 432          *      Take a pass at parsing it.
 433          */
 434         p = data;
 435         while (p < (data + data_len)) {
 436                 if ((p + 2) > (data + data_len)) goto make_tlv;
 437
 438                 if ((p + p[1] + 2) > (data + data_len)) goto make_tlv;
 439                 p += 2 + p[1];
 440         }
 441
 442         /*
 443          *      Got here... must be well formed.
 444          */
 445         head = NULL;
 446         tail = &head;
 447
 448         p = data;
 449         while (p < (data + data_len)) {
 450                 vp = paircreate(tlv->attribute | (p[0] << 8), DHCP_MAGIC_VENDOR, PW_TYPE_OCTETS);
 451                 if (!vp) {
 452                         pairfree(&head);
 453                         goto make_tlv;
 454                 }
 455
 456                 if (fr_dhcp_attr2vp(vp, p + 2, p[1]) < 0) {
 457                         pairfree(&head);
 458                         goto make_tlv;
 459                 }
 460
 461                 *tail = vp;
 462                 tail = &(vp->next);
 463                 p += 2 + p[1];
 464         }
 465
 466         /*
 467          *      The caller allocated TLV, so we need to copy the FIRST
 468          *      attribute over top of that.
 469          */
 470         if (head) {
 471                 memcpy(tlv, head, sizeof(*tlv));
 472                 head->next = NULL;
 473                 pairfree(&head);
 474         }
 475
 476         return 0;
 477
 478 make_tlv:
 479         tlv->vp_tlv = malloc(data_len);
 480         if (!tlv->vp_tlv) {
 481                 fr_strerror_printf("No memory");
 482                 return -1;
 483         }
 484         memcpy(tlv->vp_tlv, data, data_len);
 485         tlv->length = data_len;
 486
 487         return 0;
 488 }
 489
 490
 491 /*
 492  *      Decode ONE value into a VP
 493  */
 494 static int fr_dhcp_attr2vp(VALUE_PAIR *vp, const uint8_t *p, size_t alen)
 495 {
 496         switch (vp->type) {
 497         case PW_TYPE_BYTE:
 498                 if (alen != 1) goto raw;
 499                 vp->vp_integer = p[0];
 500                 break;
 501
 502         case PW_TYPE_SHORT:
 503                 if (alen != 2) goto raw;
 504                 vp->vp_integer = (p[0] << 8) | p[1];
 505                 break;
 506
 507         case PW_TYPE_INTEGER:
 508                 if (alen != 4) goto raw;
 509                 memcpy(&vp->vp_integer, p, 4);
 510                 vp->vp_integer = ntohl(vp->vp_integer);
 511                 break;
 512
 513         case PW_TYPE_IPADDR:
 514                 if (alen != 4) goto raw;
 515                 memcpy(&vp->vp_ipaddr, p , 4);
 516                 vp->length = 4;
 517                 break;
 518
 519         case PW_TYPE_STRING:
 520                 if (alen > 253) return -1;
 521                 memcpy(vp->vp_strvalue, p , alen);
 522                 vp->vp_strvalue[alen] = '\0';
 523                 break;
 524
 525         raw:
 526                 vp->type = PW_TYPE_OCTETS;
 527
 528         case PW_TYPE_OCTETS:
 529                 if (alen > 253) return -1;
 530                 memcpy(vp->vp_octets, p, alen);
 531                 break;
 532
 533         case PW_TYPE_TLV:
 534                 return decode_tlv(vp, p, alen);
 535
 536         default:
 537                 fr_strerror_printf("Internal sanity check %d %d", vp->type, __LINE__);
 538                 return -1;
 539         } /* switch over type */
 540
 541         vp->length = alen;
 542         return 0;
 543 }
 544
 545 int fr_dhcp_decode(RADIUS_PACKET *packet)
 546 {
 547         int i;
 548         uint8_t *p, *next;
 549         uint32_t giaddr;
 550         VALUE_PAIR *head, *vp, **tail;
 551         VALUE_PAIR *maxms, *mtu;
 552
 553         head = NULL;
 554         tail = &head;
 555         p = packet->data;
 556
 557         if ((fr_debug_flag > 2) && fr_log_fp) {
 558                 for (i = 0; i < packet->data_len; i++) {
 559                         if ((i & 0x0f) == 0x00) fr_strerror_printf("%d: ", i);
 560                         fprintf(fr_log_fp, "%02x ", packet->data[i]);
 561                         if ((i & 0x0f) == 0x0f) fprintf(fr_log_fp, "\n");
 562                 }
 563                 fprintf(fr_log_fp, "\n");
 564         }
 565
 566         if (packet->data[1] != 1) {
 567                 fr_strerror_printf("Packet is not Ethernet: %u",
 568                       packet->data[1]);
 569                 return -1;
 570         }
 571
 572         /*
 573          *      Decode the header.
 574          */
 575         for (i = 0; i < 14; i++) {
 576                 vp = pairmake(dhcp_header_names[i], NULL, T_OP_EQ);
 577                 if (!vp) {
 578                         fr_strerror_printf("Parse error %s", fr_strerror());
 579                         pairfree(&head);
 580                         return -1;
 581                 }
 582
 583                 if ((i == 11) &&
 584                     (packet->data[1] == 1) &&
 585                     (packet->data[2] == 6)) {
 586                         vp->type = PW_TYPE_ETHERNET;
 587                 }
 588
 589                 switch (vp->type) {
 590                 case PW_TYPE_BYTE:
 591                         vp->vp_integer = p[0];
 592                         vp->length = 1;
 593                         break;
 594
 595                 case PW_TYPE_SHORT:
 596                         vp->vp_integer = (p[0] << 8) | p[1];
 597                         vp->length = 2;
 598                         break;
 599
 600                 case PW_TYPE_INTEGER:
 601                         memcpy(&vp->vp_integer, p, 4);
 602                         vp->vp_integer = ntohl(vp->vp_integer);
 603                         vp->length = 4;
 604                         break;
 605
 606                 case PW_TYPE_IPADDR:
 607                         memcpy(&vp->vp_ipaddr, p, 4);
 608                         vp->length = 4;
 609                         break;
 610
 611                 case PW_TYPE_STRING:
 612                         memcpy(vp->vp_strvalue, p, dhcp_header_sizes[i]);
 613                         vp->vp_strvalue[dhcp_header_sizes[i]] = '\0';
 614                         vp->length = strlen(vp->vp_strvalue);
 615                         if (vp->length == 0) {
 616                                 pairfree(&vp);
 617                         }
 618                         break;
 619
 620                 case PW_TYPE_OCTETS:
 621                         memcpy(vp->vp_octets, p, packet->data[2]);
 622                         vp->length = packet->data[2];
 623                         break;
 624
 625                 case PW_TYPE_ETHERNET:
 626                         memcpy(vp->vp_ether, p, sizeof(vp->vp_ether));
 627                         vp->length = sizeof(vp->vp_ether);
 628                         break;
 629
 630                 default:
 631                         fr_strerror_printf("BAD TYPE %d", vp->type);
 632                         pairfree(&vp);
 633                         break;
 634                 }
 635                 p += dhcp_header_sizes[i];
 636
 637                 if (!vp) continue;
 638
 639                 debug_pair(vp);
 640                 *tail = vp;
 641                 tail = &vp->next;
 642         }
 643
 644         /*
 645          *      Loop over the options.
 646          */
 647         next = packet->data + 240;
 648
 649         /*
 650          *      FIXME: This should also check sname && file fields.
 651          *      See the dhcp_get_option() function above.
 652          */
 653         while (next < (packet->data + packet->data_len)) {
 654                 int num_entries, alen;
 655                 DICT_ATTR *da;
 656
 657                 p = next;
 658
 659                 if (*p == 0) break;
 660                 if (*p == 255) break; /* end of options signifier */
 661                 if ((p + 2) > (packet->data + packet->data_len)) break;
 662
 663                 next = p + 2 + p[1];
 664
 665                 if (p[1] >= 253) {
 666                         fr_strerror_printf("Attribute too long %u %u",
 667                               p[0], p[1]);
 668                         continue;
 669                 }
 670
 671                 da = dict_attrbyvalue(p[0], DHCP_MAGIC_VENDOR);
 672                 if (!da) {
 673                         fr_strerror_printf("Attribute not in our dictionary: %u",
 674                               p[0]);
 675                         continue;
 676                 }
 677
 678                 vp = NULL;
 679                 num_entries = 1;
 680                 alen = p[1];
 681                 p += 2;
 682
 683                 /*
 684                  *      Could be an array of bytes, integers, etc.
 685                  */
 686                 if (da->flags.array) {
 687                         switch (da->type) {
 688                         case PW_TYPE_BYTE:
 689                                 num_entries = alen;
 690                                 alen = 1;
 691                                 break;
 692
 693                         case PW_TYPE_SHORT: /* ignore any trailing data */
 694                                 num_entries = alen >> 1;
 695                                 alen = 2;
 696                                 break;
 697
 698                         case PW_TYPE_IPADDR:
 699                         case PW_TYPE_INTEGER:
 700                         case PW_TYPE_DATE: /* ignore any trailing data */
 701                                 num_entries = alen >> 2;
 702                                 alen = 4;
 703                                 break;
 704
 705                         default:
 706
 707                                 break; /* really an internal sanity failure */
 708                         }
 709                 }
 710
 711                 /*
 712                  *      Loop over all of the entries, building VPs
 713                  */
 714                 for (i = 0; i < num_entries; i++) {
 715                         vp = pairmake(da->name, NULL, T_OP_EQ);
 716                         if (!vp) {
 717                                 fr_strerror_printf("Cannot build attribute %s",
 718                                         fr_strerror());
 719                                 pairfree(&head);
 720                                 return -1;
 721                         }
 722
 723                         /*
 724                          *      Hack for ease of use.
 725                          */
 726                         if ((da->attr == 0x3d) &&
 727                             !da->flags.array &&
 728                             (alen == 7) && (*p == 1) && (num_entries == 1)) {
 729                                 vp->type = PW_TYPE_ETHERNET;
 730                                 memcpy(vp->vp_octets, p + 1, 6);
 731                                 vp->length = alen;
 732
 733                         } else if (fr_dhcp_attr2vp(vp, p, alen) < 0) {
 734                                         pairfree(&vp);
 735                                         pairfree(&head);
 736                                         return -1;
 737                         }
 738
 739                         *tail = vp;
 740                         while (*tail) {
 741                                 debug_pair(*tail);
 742                                 tail = &(*tail)->next;
 743                         }
 744                         p += alen;
 745                 } /* loop over array entries */
 746         } /* loop over the entire packet */
 747
 748         /*
 749          *      If DHCP request, set ciaddr to zero.
 750          */
 751
 752         /*
 753          *      Set broadcast flag for broken vendors, but only if
 754          *      giaddr isn't set.
 755          */
 756         memcpy(&giaddr, packet->data + 24, sizeof(giaddr));
 757         if (giaddr == htonl(INADDR_ANY)) {
 758                 /*
 759                  *      DHCP Opcode is request
 760                  */
 761                 vp = pairfind(head, 256, DHCP_MAGIC_VENDOR);
 762                 if (vp && vp->vp_integer == 3) {
 763                         /*
 764                          *      Vendor is "MSFT 98"
 765                          */
 766                         vp = pairfind(head, 63, DHCP_MAGIC_VENDOR);
 767                         if (vp && (strcmp(vp->vp_strvalue, "MSFT 98") == 0)) {
 768                                 vp = pairfind(head, 262, DHCP_MAGIC_VENDOR);
 769
 770                                 /*
 771                                  *      Reply should be broadcast.
 772                                  */
 773                                 if (vp) vp->vp_integer |= 0x8000;
 774                                 packet->data[10] |= 0x80;
 775                         }
 776                 }
 777         }
 778
 779         /*
 780          *      FIXME: Nuke attributes that aren't used in the normal
 781          *      header for discover/requests.
 782          */
 783         packet->vps = head;
 784
 785         /*
 786          *      Client can request a LARGER size, but not a smaller
 787          *      one.  They also cannot request a size larger than MTU.
 788          */
 789         maxms = pairfind(packet->vps, 57, DHCP_MAGIC_VENDOR);
 790         mtu = pairfind(packet->vps, 26, DHCP_MAGIC_VENDOR);
 791
 792         if (mtu && (mtu->vp_integer < DEFAULT_PACKET_SIZE)) {
 793                 fr_strerror_printf("DHCP Fatal: Client says MTU is smaller than minimum permitted by the specification.");
 794                 return -1;
 795         }
 796
 797         if (maxms && (maxms->vp_integer < DEFAULT_PACKET_SIZE)) {
 798                 fr_strerror_printf("DHCP WARNING: Client says maximum message size is smaller than minimum permitted by the specification: fixing it");
 799                 maxms->vp_integer = DEFAULT_PACKET_SIZE;
 800         }
 801
 802         if (maxms && mtu && (maxms->vp_integer > mtu->vp_integer)) {
 803                 fr_strerror_printf("DHCP WARNING: Client says MTU is smaller than maximum message size: fixing it");
 804                 maxms->vp_integer = mtu->vp_integer;
 805         }
 806
 807         if (fr_debug_flag > 0) {
 808                 for (vp = packet->vps; vp != NULL; vp = vp->next) {
 809
 810                 }
 811         }
 812
 813         if (fr_debug_flag) fflush(stdout);
 814
 815         return 0;
 816 }
 817
 818
 819 static int attr_cmp(const void *one, const void *two)
 820 {
 821         const VALUE_PAIR * const *a = one;
 822         const VALUE_PAIR * const *b = two;
 823
 824         /*
 825          *      DHCP-Message-Type is first, for simplicity.
 826          */
 827         if (((*a)->attribute == 53) &&
 828             (*b)->attribute != 53) return -1;
 829
 830         /*
 831          *      Relay-Agent is last
 832          */
 833         if (((*a)->attribute == 82) &&
 834             (*b)->attribute != 82) return +1;
 835
 836         return ((*a)->attribute - (*b)->attribute);
 837 }
 838
 839
 840 static size_t fr_dhcp_vp2attr(VALUE_PAIR *vp, uint8_t *p, size_t room)
 841 {
 842         size_t length;
 843         uint32_t lvalue;
 844
 845         /*
 846          *      FIXME: Check room!
 847          */
 848         room = room;            /* -Wunused */
 849
 850         /*
 851          *      Search for all attributes of the same
 852          *      type, and pack them into the same
 853          *      attribute.
 854          */
 855         switch (vp->type) {
 856         case PW_TYPE_BYTE:
 857                 length = 1;
 858                 *p = vp->vp_integer & 0xff;
 859                 break;
 860
 861         case PW_TYPE_SHORT:
 862                 length = 2;
 863                 p[0] = (vp->vp_integer >> 8) & 0xff;
 864                 p[1] = vp->vp_integer & 0xff;
 865                 break;
 866
 867         case PW_TYPE_INTEGER:
 868                 length = 4;
 869                 lvalue = htonl(vp->vp_integer);
 870                 memcpy(p, &lvalue, 4);
 871                 break;
 872
 873         case PW_TYPE_IPADDR:
 874                 length = 4;
 875                 memcpy(p, &vp->vp_ipaddr, 4);
 876                 break;
 877
 878         case PW_TYPE_ETHERNET:
 879                 length = 6;
 880                 memcpy(p, &vp->vp_ether, 6);
 881                 break;
 882
 883         case PW_TYPE_STRING:
 884                 memcpy(p, vp->vp_strvalue, vp->length);
 885                 length = vp->length;
 886                 break;
 887
 888         case PW_TYPE_TLV:       /* FIXME: split it on 255? */
 889                 memcpy(p, vp->vp_tlv, vp->length);
 890                 length = vp->length;
 891                 break;
 892
 893         case PW_TYPE_OCTETS:
 894                 memcpy(p, vp->vp_octets, vp->length);
 895                 length = vp->length;
 896                 break;
 897
 898         default:
 899                 fr_strerror_printf("BAD TYPE2 %d", vp->type);
 900                 length = 0;
 901                 break;
 902         }
 903
 904         return length;
 905 }
 906
 907 static VALUE_PAIR *fr_dhcp_vp2suboption(VALUE_PAIR *vps)
 908 {
 909         int length;
 910         unsigned int attribute;
 911         uint8_t *ptr;
 912         VALUE_PAIR *vp, *tlv;
 913
 914         attribute = vps->attribute & 0xffff00ff;
 915
 916         tlv = paircreate(attribute, DHCP_MAGIC_VENDOR, PW_TYPE_TLV);
 917         if (!tlv) return NULL;
 918
 919         tlv->length = 0;
 920         for (vp = vps; vp != NULL; vp = vp->next) {
 921                 /*
 922                  *      Group the attributes ONLY until we see a
 923                  *      non-TLV attribute.
 924                  */
 925                 if (!vp->flags.is_tlv ||
 926                     vp->flags.extended ||
 927                     ((vp->attribute & 0xffff00ff) != attribute)) {
 928                         break;
 929                 }
 930
 931                 tlv->length += vp->length + 2;
 932         }
 933
 934         if (!tlv->length) {
 935                 pairfree(&tlv);
 936                 return NULL;
 937         }
 938
 939         tlv->vp_tlv = malloc(tlv->length);
 940         if (!tlv->vp_tlv) {
 941                 pairfree(&tlv);
 942                 return NULL;
 943         }
 944
 945         ptr = tlv->vp_tlv;
 946         for (vp = vps; vp != NULL; vp = vp->next) {
 947                 if (!vp->flags.is_tlv ||
 948                     vp->flags.extended ||
 949                     ((vp->attribute & 0xffff00ff) != attribute)) {
 950                         break;
 951                 }
 952
 953                 length = fr_dhcp_vp2attr(vp, ptr + 2,
 954                                          tlv->vp_tlv + tlv->length - ptr);
 955                 if (length > 255) return NULL;
 956
 957                 /*
 958                  *      Pack the attribute.
 959                  */
 960                 ptr[0] = (vp->attribute & 0xff00) >> 8;
 961                 ptr[1] = length;
 962
 963                 ptr += length + 2;
 964                 vp->flags.extended = 1;
 965         }
 966
 967         return tlv;
 968 }
 969
 970
 971 int fr_dhcp_encode(RADIUS_PACKET *packet, RADIUS_PACKET *original)
 972 {
 973         int i, num_vps;
 974         uint8_t *p;
 975         VALUE_PAIR *vp;
 976         uint32_t lvalue, mms;
 977         size_t dhcp_size, length;
 978         dhcp_packet_t *dhcp;
 979         char buffer[1024];
 980
 981         if (packet->data) return 0;
 982
 983         packet->data = malloc(MAX_PACKET_SIZE);
 984         if (!packet->data) return -1;
 985
 986         packet->data_len = MAX_PACKET_SIZE;
 987
 988         if (packet->code == 0) packet->code = PW_DHCP_NAK;
 989
 990         /*
 991          *      If there's a request, use it as a template.
 992          *      Otherwise, assume that the caller has set up
 993          *      everything appropriately.
 994          */
 995         if (original) {
 996                 packet->dst_ipaddr.af = AF_INET;
 997                 packet->src_ipaddr.af = AF_INET;
 998
 999                 packet->dst_port = original->src_port;
1000                 packet->src_port = original->dst_port;
1001
1002                 /*
1003                  *      Note that for DHCP, we NEVER send the response
1004                  *      to the source IP address of the request.  It
1005                  *      may have traversed multiple relays, and we
1006                  *      need to send the request to the relay closest
1007                  *      to the client.
1008                  *
1009                  *      if giaddr, send to giaddr.
1010                  *      if NAK, send broadcast.
1011                  *      if broadcast flag, send broadcast.
1012                  *      if ciaddr is empty, send broadcast.
1013                  *      otherwise unicast to ciaddr.
1014                  */
1015
1016                 /*
1017                  *      FIXME: alignment issues.  We likely don't want to
1018                  *      de-reference the packet structure directly..
1019                  */
1020                 dhcp = (dhcp_packet_t *) original->data;
1021
1022                 /*
1023                  *      Default to sending it via sendto(), without using
1024                  *      raw sockets.
1025                  */
1026                 packet->offset = 1;
1027
1028                 if (dhcp->giaddr != htonl(INADDR_ANY)) {
1029                         packet->dst_ipaddr.ipaddr.ip4addr.s_addr = dhcp->giaddr;
1030
1031                         if (dhcp->giaddr != htonl(INADDR_LOOPBACK)) {
1032                                 packet->dst_port = original->dst_port;
1033                         } else {
1034                                 packet->dst_port = original->src_port; /* debugging */
1035                         }
1036
1037                 } else if ((packet->code == PW_DHCP_NAK) ||
1038                            ((dhcp->flags & 0x8000) != 0) ||
1039                            (dhcp->ciaddr == htonl(INADDR_ANY))) {
1040                         /*
1041                          *      The kernel will take care of sending it to
1042                          *      the broadcast MAC.
1043                          */
1044                         packet->dst_ipaddr.ipaddr.ip4addr.s_addr = htonl(INADDR_BROADCAST);
1045
1046                 } else {
1047                         /*
1048                          *      It was broadcast to us: we need to
1049                          *      broadcast the response.
1050                          */
1051                         if (packet->src_ipaddr.ipaddr.ip4addr.s_addr != dhcp->ciaddr) {
1052                                 packet->offset = 0;
1053                         }
1054                         packet->dst_ipaddr.ipaddr.ip4addr.s_addr = dhcp->ciaddr;
1055                 }
1056
1057                 /*
1058                  *      Rewrite the source IP to be our own, if we know it.
1059                  */
1060                 if (packet->src_ipaddr.ipaddr.ip4addr.s_addr == htonl(INADDR_BROADCAST)) {
1061                         packet->src_ipaddr.ipaddr.ip4addr.s_addr = htonl(INADDR_ANY);
1062                 }
1063         } else {
1064                 memset(packet->data, 0, packet->data_len);
1065         }
1066
1067         if (fr_debug_flag > 1) {
1068                 char type_buf[64];
1069                 const char *name = type_buf;
1070                 char src_ip_buf[256], dst_ip_buf[256];
1071
1072                 if ((packet->code >= PW_DHCP_DISCOVER) &&
1073                     (packet->code <= PW_DHCP_INFORM)) {
1074                         name = dhcp_message_types[packet->code - PW_DHCP_OFFSET];
1075                 } else {
1076                         snprintf(type_buf, sizeof(type_buf), "%d",
1077                                  packet->code - PW_DHCP_OFFSET);
1078                 }
1079
1080                 DEBUG("Sending %s of id %08x from %s:%d to %s:%d\n",
1081                        name, (unsigned int) packet->id,
1082                        inet_ntop(packet->src_ipaddr.af,
1083                                  &packet->src_ipaddr.ipaddr,
1084                                  src_ip_buf, sizeof(src_ip_buf)),
1085                        packet->src_port,
1086                        inet_ntop(packet->dst_ipaddr.af,
1087                                  &packet->dst_ipaddr.ipaddr,
1088                                  dst_ip_buf, sizeof(dst_ip_buf)),
1089                        packet->dst_port);
1090
1091                 if (fr_debug_flag) {
1092                         for (i = 256; i < 269; i++) {
1093                                 vp = pairfind(packet->vps, i,
1094                                               DHCP_MAGIC_VENDOR);
1095                                 if (!vp) continue;
1096
1097                                 debug_pair(vp);
1098                         }
1099                 }
1100         }
1101
1102         p = packet->data;
1103
1104         mms = DEFAULT_PACKET_SIZE; /* maximum message size */
1105
1106         if (original) {
1107                 /*
1108                  *      Clients can request a LARGER size, but not a
1109                  *      smaller one.  They also cannot request a size
1110                  *      larger than MTU.
1111                  */
1112                 vp = pairfind(original->vps, 57, DHCP_MAGIC_VENDOR);
1113                 if (vp && (vp->vp_integer > mms)) {
1114                         mms = vp->vp_integer;
1115
1116                         if (mms > MAX_PACKET_SIZE) mms = MAX_PACKET_SIZE;
1117                 }
1118         }
1119
1120         /*
1121          *      RFC 3118: Authentication option.
1122          */
1123         vp = pairfind(packet->vps, 90, DHCP_MAGIC_VENDOR);
1124         if (vp) {
1125                 if (vp->length < 2) {
1126                         memset(vp->vp_octets + vp->length, 0,
1127                                2 - vp->length);
1128                         vp->length = 2;
1129                 }
1130
1131                 if (vp->length < 3) {
1132                         struct timeval tv;
1133
1134                         gettimeofday(&tv, NULL);
1135                         vp->vp_octets[2] = 0;
1136                         timeval2ntp(&tv, vp->vp_octets + 3);
1137                         vp->length = 3 + 8;
1138                 }
1139
1140                 /*
1141                  *      Configuration token (clear-text token)
1142                  */
1143                 if (vp->vp_octets[0] == 0) {
1144                         VALUE_PAIR *pass;
1145                         vp->vp_octets[1] = 0;
1146
1147                         pass = pairfind(packet->vps, PW_CLEARTEXT_PASSWORD, DHCP_MAGIC_VENDOR);
1148                         if (pass) {
1149                                 length = pass->length;
1150                                 if ((length + 11) > sizeof(vp->vp_octets)) {
1151                                         length -= ((length + 11) - sizeof(vp->vp_octets));
1152                                 }
1153                                 memcpy(vp->vp_octets + 11, pass->vp_strvalue,
1154                                        length);
1155                                 vp->length = length + 11;
1156                         } else {
1157                                 vp->length = 11 + 8;
1158                                 memset(vp->vp_octets + 11, 0, 8);
1159                                 vp->length = 11 + 8;
1160                         }
1161                 } else {        /* we don't support this type! */
1162                         fr_strerror_printf("DHCP-Authentication %d unsupported",
1163                                 vp->vp_octets[0]);
1164                 }
1165         }
1166
1167         vp = pairfind(packet->vps, 256, DHCP_MAGIC_VENDOR);
1168         if (vp) {
1169                 *p++ = vp->vp_integer & 0xff;
1170         } else {
1171                 if (!original) {
1172                         *p++ = 1;       /* client message */
1173                 } else {
1174                         *p++ = 2;       /* server message */
1175                 }
1176         }
1177         *p++ = 1;               /* hardware type = ethernet */
1178         *p++ = 6;               /* 6 bytes of ethernet */
1179
1180         vp = pairfind(packet->vps, 259, DHCP_MAGIC_VENDOR);
1181         if (vp) {
1182                 *p++ = vp->vp_integer & 0xff;
1183         } else {
1184                 *p++ = 0;               /* hops */
1185         }
1186
1187         if (original) { /* Xid */
1188                 memcpy(p, original->data + 4, 4);
1189         } else {
1190                 lvalue = fr_rand();
1191                 memcpy(p, &lvalue, 4);
1192         }
1193         p += 4;
1194
1195         memset(p, 0, 2);        /* secs are zero */
1196         p += 2;
1197
1198         if (original) {
1199                 memcpy(p, original->data + 10, 6); /* copy flags && ciaddr */
1200         }
1201
1202         /*
1203          *      Allow the admin to set the broadcast flag.
1204          */
1205         vp = pairfind(packet->vps, 262, DHCP_MAGIC_VENDOR);
1206         if (vp) {
1207                 p[0] |= (vp->vp_integer & 0xff00) >> 8;
1208                 p[1] |= (vp->vp_integer & 0xff);
1209         }
1210
1211         p += 6;
1212
1213         /*
1214          *      Set client IP address.
1215          */
1216         vp = pairfind(packet->vps, 264, DHCP_MAGIC_VENDOR); /* Your IP address */
1217         if (vp) {
1218                 lvalue = vp->vp_ipaddr;
1219         } else {
1220                 lvalue = htonl(INADDR_ANY);
1221         }
1222         memcpy(p, &lvalue, 4);  /* your IP address */
1223         p += 4;
1224
1225         vp = pairfind(packet->vps, 265, DHCP_MAGIC_VENDOR); /* server IP address */
1226         if (!vp) vp = pairfind(packet->vps, 54, DHCP_MAGIC_VENDOR); /* identifier */
1227         if (vp) {
1228                 lvalue = vp->vp_ipaddr;
1229         } else {
1230                 lvalue = htonl(INADDR_ANY);
1231         }
1232         memcpy(p, &lvalue, 4);  /* Server IP address */
1233         p += 4;
1234
1235         if (original) {
1236                 memcpy(p, original->data + 24, 4); /* copy gateway IP address */
1237         } else {
1238                 vp = pairfind(packet->vps, 266, DHCP_MAGIC_VENDOR);
1239                 if (vp) {
1240                         lvalue = vp->vp_ipaddr;
1241                 } else {
1242                         lvalue = htonl(INADDR_NONE);
1243                 }
1244                 memcpy(p, &lvalue, 4);
1245         }
1246         p += 4;
1247
1248         if (original) {
1249                 memcpy(p, original->data + 28, DHCP_CHADDR_LEN);
1250         } else {
1251                 vp = pairfind(packet->vps, 267, DHCP_MAGIC_VENDOR);
1252                 if (vp) {
1253                         if (vp->length > DHCP_CHADDR_LEN) {
1254                                 memcpy(p, vp->vp_octets, DHCP_CHADDR_LEN);
1255                         } else {
1256                                 memcpy(p, vp->vp_octets, vp->length);
1257                         }
1258                 }
1259         }
1260         p += DHCP_CHADDR_LEN;
1261
1262         /*
1263          *      Zero our sname && filename fields.
1264          */
1265         memset(p, 0, DHCP_SNAME_LEN + DHCP_FILE_LEN);
1266         p += DHCP_SNAME_LEN;
1267
1268         /*
1269          *      Copy over DHCP-Boot-Filename.
1270          *
1271          *      FIXME: This copy should be delayed until AFTER the options
1272          *      have been processed.  If there are too many options for
1273          *      the packet, then they go into the sname && filename fields.
1274          *      When that happens, the boot filename is passed as an option,
1275          *      instead of being placed verbatim in the filename field.
1276          */
1277         vp = pairfind(packet->vps, 269, DHCP_MAGIC_VENDOR);
1278         if (vp) {
1279                 if (vp->length > DHCP_FILE_LEN) {
1280                         memcpy(p, vp->vp_strvalue, DHCP_FILE_LEN);
1281                 } else {
1282                         memcpy(p, vp->vp_strvalue, vp->length);
1283                 }
1284         }
1285         p += DHCP_FILE_LEN;
1286
1287         lvalue = htonl(DHCP_OPTION_MAGIC_NUMBER); /* DHCP magic number */
1288         memcpy(p, &lvalue, 4);
1289         p += 4;
1290
1291         /*
1292          *      Print the header.
1293          */
1294         if (fr_debug_flag > 1) {
1295                 uint8_t *pp = p;
1296
1297                 p = packet->data;
1298
1299                 for (i = 0; i < 14; i++) {
1300                         vp = pairmake(dhcp_header_names[i], NULL, T_OP_EQ);
1301                         if (!vp) {
1302                                 fr_strerror_printf("Parse error %s", fr_strerror());
1303                                 return -1;
1304                         }
1305
1306                         switch (vp->type) {
1307                         case PW_TYPE_BYTE:
1308                                 vp->vp_integer = p[0];
1309                                 vp->length = 1;
1310                                 break;
1311
1312                         case PW_TYPE_SHORT:
1313                                 vp->vp_integer = (p[0] << 8) | p[1];
1314                                 vp->length = 2;
1315                                 break;
1316
1317                         case PW_TYPE_INTEGER:
1318                                 memcpy(&vp->vp_integer, p, 4);
1319                                 vp->vp_integer = ntohl(vp->vp_integer);
1320                                 vp->length = 4;
1321                                 break;
1322
1323                         case PW_TYPE_IPADDR:
1324                                 memcpy(&vp->vp_ipaddr, p, 4);
1325                                 vp->length = 4;
1326                                 break;
1327
1328                         case PW_TYPE_STRING:
1329                                 memcpy(vp->vp_strvalue, p, dhcp_header_sizes[i]);
1330                                 vp->vp_strvalue[dhcp_header_sizes[i]] = '\0';
1331                                 vp->length = strlen(vp->vp_strvalue);
1332                                 break;
1333
1334                         case PW_TYPE_OCTETS: /* only for Client HW Address */
1335                                 memcpy(vp->vp_octets, p, packet->data[2]);
1336                                 vp->length = packet->data[2];
1337                                 break;
1338
1339                         case PW_TYPE_ETHERNET: /* only for Client HW Address */
1340                                 memcpy(vp->vp_ether, p, sizeof(vp->vp_ether));
1341                                 vp->length = sizeof(vp->vp_ether);
1342                                 break;
1343
1344                         default:
1345                                 fr_strerror_printf("Internal sanity check failed %d %d", vp->type, __LINE__);
1346                                 pairfree(&vp);
1347                                 break;
1348                         }
1349
1350                         p += dhcp_header_sizes[i];
1351
1352                         vp_prints(buffer, sizeof(buffer), vp);
1353                         fr_strerror_printf("\t%s", buffer);
1354                         pairfree(&vp);
1355                 }
1356
1357                 /*
1358                  *      Jump over DHCP magic number, response, etc.
1359                  */
1360                 p = pp;
1361         }
1362
1363         /*
1364          *      Before packing the attributes, re-order them so that
1365          *      the array ones are all contiguous.  This simplifies
1366          *      the later code.
1367          */
1368         num_vps = 0;
1369         for (vp = packet->vps; vp != NULL; vp = vp->next) {
1370                 num_vps++;
1371         }
1372         if (num_vps > 1) {
1373                 VALUE_PAIR **array, **last;
1374
1375                 array = malloc(num_vps * sizeof(VALUE_PAIR *));
1376
1377                 i = 0;
1378                 for (vp = packet->vps; vp != NULL; vp = vp->next) {
1379                         array[i++] = vp;
1380                 }
1381
1382                 /*
1383                  *      Sort the attributes.
1384                  */
1385                 qsort(array, (size_t) num_vps, sizeof(VALUE_PAIR *),
1386                       attr_cmp);
1387
1388                 last = &packet->vps;
1389                 for (i = 0; i < num_vps; i++) {
1390                         *last = array[i];
1391                         array[i]->next = NULL;
1392                         last = &(array[i]->next);
1393                 }
1394                 free(array);
1395         }
1396
1397         p[0] = 0x35;            /* DHCP-Message-Type */
1398         p[1] = 1;
1399         p[2] = packet->code - PW_DHCP_OFFSET;
1400         p += 3;
1401
1402         /*
1403          *      Pack in the attributes.
1404          */
1405         vp = packet->vps;
1406         while (vp) {
1407                 int num_entries = 1;
1408                 VALUE_PAIR *same;
1409                 uint8_t *plength, *pattr;
1410
1411                 if (vp->vendor != DHCP_MAGIC_VENDOR) goto next;
1412                 if (vp->attribute == 53) goto next; /* already done */
1413                 if ((vp->attribute > 255) &&
1414                     (DHCP_BASE_ATTR(vp->attribute) != PW_DHCP_OPTION_82)) goto next;
1415
1416                 debug_pair(vp);
1417                 if (vp->flags.extended) goto next;
1418
1419                 length = vp->length;
1420
1421                 for (same = vp->next; same != NULL; same = same->next) {
1422                         if (same->attribute != vp->attribute) break;
1423                         num_entries++;
1424                 }
1425
1426                 /*
1427                  *      For client-identifier
1428                  */
1429                 if ((vp->type == PW_TYPE_ETHERNET) &&
1430                     (vp->length == 6) &&
1431                     (num_entries == 1)) {
1432                         vp->type = PW_TYPE_OCTETS;
1433                         memmove(vp->vp_octets + 1, vp->vp_octets, 6);
1434                         vp->vp_octets[0] = 1;
1435                 }
1436
1437                 pattr = p;
1438                 *(p++) = vp->attribute & 0xff;
1439                 plength = p;
1440                 *(p++) = 0;     /* header isn't included in attr length */
1441
1442                 for (i = 0; i < num_entries; i++) {
1443                         if (fr_debug_flag > 1) {
1444                                 vp_prints(buffer, sizeof(buffer), vp);
1445                                 fr_strerror_printf("\t%s", buffer);
1446                         }
1447
1448                         if (vp->flags.is_tlv) {
1449                                 VALUE_PAIR *tlv;
1450
1451                                 /*
1452                                  *      Should NOT have been encoded yet!
1453                                  */
1454                                 tlv = fr_dhcp_vp2suboption(vp);
1455
1456                                 /*
1457                                  *      Ignore it if there's an issue
1458                                  *      encoding it.
1459                                  */
1460                                 if (!tlv) goto next;
1461
1462                                 tlv->next = vp->next;
1463                                 vp->next = tlv;
1464                                 vp = tlv;
1465                         }
1466
1467                         length = fr_dhcp_vp2attr(vp, p, 0);
1468
1469                         /*
1470                          *      This will never happen due to FreeRADIUS
1471                          *      limitations: sizeof(vp->vp_octets) < 255
1472                          */
1473                         if (length > 255) {
1474                                 fr_strerror_printf("WARNING Ignoring too long attribute %s!", vp->name);
1475                                 break;
1476                         }
1477
1478                         /*
1479                          *      More than one attribute of the same type
1480                          *      in a row: they are packed together
1481                          *      into the same TLV.  If we overflow,
1482                          *      go bananas!
1483                          */
1484                         if ((*plength + length) > 255) {
1485                                 fr_strerror_printf("WARNING Ignoring too long attribute %s!", vp->name);
1486                                 break;
1487                         }
1488
1489                         *plength += length;
1490                         p += length;
1491
1492                         if (vp->next &&
1493                             (vp->next->attribute == vp->attribute))
1494                                 vp = vp->next;
1495                 } /* loop over num_entries */
1496
1497         next:
1498                 vp = vp->next;
1499         }
1500
1501         p[0] = 0xff;            /* end of option option */
1502         p[1] = 0x00;
1503         p += 2;
1504         dhcp_size = p - packet->data;
1505
1506         /*
1507          *      FIXME: if (dhcp_size > mms),
1508          *        then we put the extra options into the "sname" and "file"
1509          *        fields, AND set the "end option option" in the "options"
1510          *        field.  We also set the "overload option",
1511          *        and put options into the "file" field, followed by
1512          *        the "sname" field.  Where each option is completely
1513          *        enclosed in the "file" and/or "sname" field, AND
1514          *        followed by the "end of option", and MUST be followed
1515          *        by padding option.
1516          *
1517          *      Yuck.  That sucks...
1518          */
1519         packet->data_len = dhcp_size;
1520
1521         if (original) {
1522                 /*
1523                  *      FIXME: This may set it to broadcast, which we don't
1524                  *      want.  Instead, set it to the real address of the
1525                  *      socket.
1526                  */
1527                 packet->src_ipaddr = original->dst_ipaddr;
1528
1529                 packet->sockfd = original->sockfd;
1530         }
1531
1532         if (packet->data_len < DEFAULT_PACKET_SIZE) {
1533                 memset(packet->data + packet->data_len, 0,
1534                        DEFAULT_PACKET_SIZE - packet->data_len);
1535                 packet->data_len = DEFAULT_PACKET_SIZE;
1536         }
1537
1538         if ((fr_debug_flag > 2) && fr_log_fp) {
1539                 for (i = 0; i < packet->data_len; i++) {
1540                         if ((i & 0x0f) == 0x00) fprintf(fr_log_fp, "%d: ", i);
1541                         fprintf(fr_log_fp, "%02x ", packet->data[i]);
1542                         if ((i & 0x0f) == 0x0f) fprintf(fr_log_fp, "\n");
1543                 }
1544                 fprintf(fr_log_fp, "\n");
1545         }
1546
1547         return 0;
1548 }
1549
1550 int fr_dhcp_add_arp_entry(int fd, const char *interface,
1551                           VALUE_PAIR *macaddr, VALUE_PAIR *ip)
1552 {
1553 #ifdef SIOCSARP
1554         struct sockaddr_in *sin;
1555         struct arpreq req;
1556
1557         if (macaddr->length > sizeof (req.arp_ha.sa_data)) {
1558                 fr_strerror_printf("ERROR: DHCP only supports up to %u octets for "
1559                                    "Client Hardware Address (got %zu octets)\n",
1560                                    sizeof(req.arp_ha.sa_data),
1561                                    macaddr->length);
1562                 return -1;
1563         }
1564
1565         memset(&req, 0, sizeof(req));
1566         sin = (struct sockaddr_in *) &req.arp_pa;
1567         sin->sin_family = AF_INET;
1568         sin->sin_addr.s_addr = ip->vp_ipaddr;
1569         strlcpy(req.arp_dev, interface, sizeof(req.arp_dev));
1570         memcpy(&req.arp_ha.sa_data, macaddr->vp_octets, macaddr->length);
1571
1572         req.arp_flags = ATF_COM;
1573         if (ioctl(fd, SIOCSARP, &req) < 0) {
1574                 fr_strerror_printf("DHCP: Failed to add entry in ARP cache: %s (%d)",
1575                                    strerror(errno), errno);
1576                 return -1;
1577         }
1578
1579         return 0;
1580 #else
1581         fd = fd;                /* -Wunused */
1582         interface = interface;  /* -Wunused */
1583         macaddr = macaddr;      /* -Wunused */
1584         ip = ip;                /* -Wunused */
1585
1586         fr_strerror_printf("Adding ARP entry is unsupported on this system");
1587         return -1;
1588 #endif
1589 }
1590
1591 #endif /* WITH_DHCP */