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         int overload = 0;
 147         int field = DHCP_OPTION_FIELD;
 148         size_t where, size;
 149         uint8_t *data = packet->options;
 150
 151         where = 0;
 152         size = packet_size - offsetof(dhcp_packet_t, options);
 153         data = &packet->options[where];
 154
 155         while (where < size) {
 156                 if (data[0] == 0) { /* padding */
 157                         where++;
 158                         continue;
 159                 }
 160
 161                 if (data[0] == 255) { /* end of options */
 162                         if ((field == DHCP_OPTION_FIELD) &&
 163                             (overload & DHCP_FILE_FIELD)) {
 164                                 data = packet->file;
 165                                 where = 0;
 166                                 size = sizeof(packet->file);
 167                                 field = DHCP_FILE_FIELD;
 168                                 continue;
 169
 170                         } else if ((field == DHCP_FILE_FIELD) &&
 171                                    (overload && DHCP_SNAME_FIELD)) {
 172                                 data = packet->sname;
 173                                 where = 0;
 174                                 size = sizeof(packet->sname);
 175                                 field = DHCP_SNAME_FIELD;
 176                                 continue;
 177                         }
 178
 179                         return NULL;
 180                 }
 181
 182                 /*
 183                  *      We MUST have a real option here.
 184                  */
 185                 if ((where + 2) > size) {
 186                         fr_strerror_printf("Options overflow field at %u",
 187                                            (unsigned int) (data - (uint8_t *) packet));
 188                         return NULL;
 189                 }
 190
 191                 if ((where + 2 + data[1]) > size) {
 192                         fr_strerror_printf("Option length overflows field at %u",
 193                                            (unsigned int) (data - (uint8_t *) packet));
 194                         return NULL;
 195                 }
 196
 197                 if (data[0] == option) return data;
 198
 199                 if (data[0] == 52) { /* overload sname and/or file */
 200                         overload = data[3];
 201                 }
 202
 203                 where += data[1] + 2;
 204                 data += data[1] + 2;
 205         }
 206
 207         return NULL;
 208 }
 209
 210 /*
 211  *      DHCPv4 is only for IPv4.  Broadcast only works if udpfromto is
 212  *      defined.
 213  */
 214 RADIUS_PACKET *fr_dhcp_recv(int sockfd)
 215 {
 216         ssize_t                 len;
 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(NULL, 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         len = recvfromto(sockfd, packet->data, MAX_PACKET_SIZE, 0,
 245                          (struct sockaddr *)&src, &sizeof_src,
 246                          (struct sockaddr *)&dst, &sizeof_dst);
 247 #else
 248         len = recvfrom(sockfd, packet->data, MAX_PACKET_SIZE, 0,
 249                        (struct sockaddr *)&src, &sizeof_src);
 250 #endif
 251
 252         if (len <= 0) {
 253                 fr_strerror_printf("Failed reading DHCP socket: %s", strerror(errno));
 254                 rad_free(&packet);
 255                 return NULL;
 256         }
 257
 258         if (len < MIN_PACKET_SIZE) {
 259                 fr_strerror_printf("DHCP packet is too small (%d < %d)",
 260                                    (int) 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         packet->data_len = len;
 280
 281         memcpy(&magic, packet->data + 236, 4);
 282         magic = ntohl(magic);
 283         if (magic != DHCP_OPTION_MAGIC_NUMBER) {
 284                 fr_strerror_printf("Cannot do BOOTP");
 285                 rad_free(&packet);
 286                 return NULL;
 287         }
 288
 289         /*
 290          *      Create unique keys for the packet.
 291          */
 292         memcpy(&magic, packet->data + 4, 4);
 293         packet->id = ntohl(magic);
 294
 295         code = dhcp_get_option((dhcp_packet_t *) packet->data,
 296                                packet->data_len, 53);
 297         if (!code) {
 298                 fr_strerror_printf("No message-type option was found in the packet");
 299                 rad_free(&packet);
 300                 return NULL;
 301         }
 302
 303         if ((code[1] < 1) || (code[2] == 0) || (code[2] > 8)) {
 304                 fr_strerror_printf("Unknown value for message-type option");
 305                 rad_free(&packet);
 306                 return NULL;
 307         }
 308
 309         packet->code = code[2] | PW_DHCP_OFFSET;
 310
 311         /*
 312          *      Create a unique vector from the MAC address and the
 313          *      DHCP opcode.  This is a hack for the RADIUS
 314          *      infrastructure in the rest of the server.
 315          *
 316          *      Note: packet->data[2] == 6, which is smaller than
 317          *      sizeof(packet->vector)
 318          *
 319          *      FIXME:  Look for client-identifier in packet,
 320          *      and use that, too?
 321          */
 322         memset(packet->vector, 0, sizeof(packet->vector));
 323         memcpy(packet->vector, packet->data + 28, packet->data[2]);
 324         packet->vector[packet->data[2]] = packet->code & 0xff;
 325
 326         /*
 327          *      FIXME: for DISCOVER / REQUEST: src_port == dst_port + 1
 328          *      FIXME: for OFFER / ACK       : src_port = dst_port - 1
 329          */
 330
 331         /*
 332          *      Unique keys are xid, client mac, and client ID?
 333          */
 334
 335         /*
 336          *      FIXME: More checks, like DHCP packet type?
 337          */
 338
 339         sizeof_dst = sizeof(dst);
 340
 341 #ifndef WITH_UDPFROMTO
 342         /*
 343          *      This should never fail...
 344          */
 345         if (getsockname(sockfd, (struct sockaddr *) &dst, &sizeof_dst) < 0) {
 346                 fr_strerror_printf("getsockname failed: %s", strerror(errno));
 347                 rad_free(&packet);
 348                 return NULL;
 349         }
 350 #endif
 351
 352         fr_sockaddr2ipaddr(&dst, sizeof_dst, &packet->dst_ipaddr, &port);
 353         packet->dst_port = port;
 354
 355         fr_sockaddr2ipaddr(&src, sizeof_src, &packet->src_ipaddr, &port);
 356         packet->src_port = port;
 357
 358         if (fr_debug_flag > 1) {
 359                 char type_buf[64];
 360                 const char *name = type_buf;
 361                 char src_ip_buf[256], dst_ip_buf[256];
 362
 363                 if ((packet->code >= PW_DHCP_DISCOVER) &&
 364                     (packet->code <= PW_DHCP_INFORM)) {
 365                         name = dhcp_message_types[packet->code - PW_DHCP_OFFSET];
 366                 } else {
 367                         snprintf(type_buf, sizeof(type_buf), "%d",
 368                                  packet->code - PW_DHCP_OFFSET);
 369                 }
 370
 371                 DEBUG("Received %s of id %08x from %s:%d to %s:%d\n",
 372                        name, (unsigned int) packet->id,
 373                        inet_ntop(packet->src_ipaddr.af,
 374                                  &packet->src_ipaddr.ipaddr,
 375                                  src_ip_buf, sizeof(src_ip_buf)),
 376                        packet->src_port,
 377                        inet_ntop(packet->dst_ipaddr.af,
 378                                  &packet->dst_ipaddr.ipaddr,
 379                                  dst_ip_buf, sizeof(dst_ip_buf)),
 380                        packet->dst_port);
 381         }
 382
 383         return packet;
 384 }
 385
 386
 387 /*
 388  *      Send a DHCP packet.
 389  */
 390 int fr_dhcp_send(RADIUS_PACKET *packet)
 391 {
 392         struct sockaddr_storage dst;
 393         socklen_t               sizeof_dst;
 394 #ifdef WITH_UDPFROMTO
 395         struct sockaddr_storage src;
 396         socklen_t               sizeof_src;
 397 #endif
 398
 399         if (!fr_ipaddr2sockaddr(&packet->dst_ipaddr, packet->dst_port,
 400                                 &dst, &sizeof_dst)) {
 401                 return -1;
 402         }
 403
 404         /*
 405          *      The client doesn't yet have an IP address, but is
 406          *      expecting an ethernet packet unicast to it's MAC
 407          *      address.  We need to build a raw frame.
 408          */
 409         if (packet->offset == 0) {
 410                 /*
 411                  *      FIXME: Insert code here!
 412                  */
 413         }
 414
 415 #ifndef WITH_UDPFROMTO
 416         /*
 417          *      Assume that the packet is encoded before sending it.
 418          */
 419         return sendto(packet->sockfd, packet->data, packet->data_len, 0,
 420                       (struct sockaddr *)&dst, sizeof_dst);
 421 #else
 422         if (!fr_ipaddr2sockaddr(&packet->src_ipaddr, packet->src_port,
 423                                 &src, &sizeof_src)) {
 424                 return -1;
 425         }
 426
 427         return sendfromto(packet->sockfd,
 428                           packet->data, packet->data_len, 0,
 429                           (struct sockaddr *)&src, sizeof_src,
 430                           (struct sockaddr *)&dst, sizeof_dst);
 431 #endif
 432 }
 433
 434 static int fr_dhcp_attr2vp(VALUE_PAIR *vp, const uint8_t *p, size_t alen);
 435
 436 static int decode_tlv(VALUE_PAIR *tlv, const uint8_t *data, size_t data_len)
 437 {
 438         const uint8_t *p;
 439         VALUE_PAIR *head, **tail, *vp;
 440
 441         /*
 442          *      Take a pass at parsing it.
 443          */
 444         p = data;
 445         while (p < (data + data_len)) {
 446                 if ((p + 2) > (data + data_len)) goto make_tlv;
 447
 448                 if ((p + p[1] + 2) > (data + data_len)) goto make_tlv;
 449                 p += 2 + p[1];
 450         }
 451
 452         /*
 453          *      Got here... must be well formed.
 454          */
 455         head = NULL;
 456         tail = &head;
 457
 458         p = data;
 459         while (p < (data + data_len)) {
 460                 vp = paircreate(tlv->da->attr | (p[0] << 8), DHCP_MAGIC_VENDOR);
 461                 if (!vp) {
 462                         pairfree(&head);
 463                         goto make_tlv;
 464                 }
 465
 466                 if (fr_dhcp_attr2vp(vp, p + 2, p[1]) < 0) {
 467                         pairfree(&head);
 468                         goto make_tlv;
 469                 }
 470
 471                 *tail = vp;
 472                 tail = &(vp->next);
 473                 p += 2 + p[1];
 474         }
 475
 476         /*
 477          *      The caller allocated TLV, so we need to copy the FIRST
 478          *      attribute over top of that.
 479          */
 480         if (head) {
 481                 memcpy(tlv, head, sizeof(*tlv));
 482                 head->next = NULL;
 483                 pairfree(&head);
 484         }
 485
 486         return 0;
 487
 488 make_tlv:
 489         tlv->vp_tlv = malloc(data_len);
 490         if (!tlv->vp_tlv) {
 491                 fr_strerror_printf("No memory");
 492                 return -1;
 493         }
 494         memcpy(tlv->vp_tlv, data, data_len);
 495         tlv->length = data_len;
 496
 497         return 0;
 498 }
 499
 500
 501 /*
 502  *      Decode ONE value into a VP
 503  */
 504 static int fr_dhcp_attr2vp(VALUE_PAIR *vp, const uint8_t *p, size_t alen)
 505 {
 506         switch (vp->da->type) {
 507         case PW_TYPE_BYTE:
 508                 if (alen != 1) goto raw;
 509                 vp->vp_integer = p[0];
 510                 break;
 511
 512         case PW_TYPE_SHORT:
 513                 if (alen != 2) goto raw;
 514                 memcpy(&vp->vp_integer, p, 2);
 515                 vp->vp_integer = ntohs(vp->vp_integer);
 516                 break;
 517
 518         case PW_TYPE_INTEGER:
 519                 if (alen != 4) goto raw;
 520                 memcpy(&vp->vp_integer, p, 4);
 521                 vp->vp_integer = ntohl(vp->vp_integer);
 522                 break;
 523
 524         case PW_TYPE_IPADDR:
 525                 if (alen != 4) goto raw;
 526                 /*
 527                  *      Keep value in Network Order!
 528                  */
 529                 memcpy(&vp->vp_ipaddr, p , 4);
 530                 vp->length = 4;
 531                 break;
 532
 533         case PW_TYPE_STRING:
 534                 if (alen > 253) return -1;
 535                 memcpy(vp->vp_strvalue, p , alen);
 536                 vp->vp_strvalue[alen] = '\0';
 537                 break;
 538
 539         /*
 540          *      Value doesn't match up with attribute type, overwrite the
 541          *      vp's original DICT_ATTR with an unknown one.
 542          */
 543         raw:
 544                 if (pair2unknown(vp) < 0) return -1;
 545
 546         case PW_TYPE_OCTETS:
 547                 if (alen > 253) return -1;
 548                 memcpy(vp->vp_octets, p, alen);
 549                 break;
 550
 551         case PW_TYPE_TLV:
 552                 return decode_tlv(vp, p, alen);
 553
 554         default:
 555                 fr_strerror_printf("Internal sanity check %d %d", vp->da->type, __LINE__);
 556                 return -1;
 557         } /* switch over type */
 558
 559         vp->length = alen;
 560         return 0;
 561 }
 562
 563 ssize_t fr_dhcp_decode_options(uint8_t *data, size_t len, VALUE_PAIR **head)
 564 {
 565         int i;
 566         VALUE_PAIR *vp, **tail;
 567         uint8_t *p, *next;
 568         next = data;
 569
 570         *head = NULL;
 571         tail = head;
 572         /*
 573          *      FIXME: This should also check sname && file fields.
 574          *      See the dhcp_get_option() function above.
 575          */
 576         while (next < (data + len)) {
 577                 int num_entries, alen;
 578                 const DICT_ATTR *da;
 579
 580                 p = next;
 581
 582                 if (*p == 0) break;
 583                 if (*p == 255) break; /* end of options signifier */
 584                 if ((p + 2) > (data + len)) break;
 585
 586                 next = p + 2 + p[1];
 587
 588                 if (p[1] >= 253) {
 589                         fr_strerror_printf("Attribute too long %u %u",
 590                                            p[0], p[1]);
 591                         continue;
 592                 }
 593
 594                 da = dict_attrbyvalue(p[0], DHCP_MAGIC_VENDOR);
 595                 if (!da) {
 596                         fr_strerror_printf("Attribute not in our dictionary: %u",
 597                                            p[0]);
 598                         continue;
 599                 }
 600
 601                 vp = NULL;
 602                 num_entries = 1;
 603                 alen = p[1];
 604                 p += 2;
 605
 606                 /*
 607                  *      Could be an array of bytes, integers, etc.
 608                  */
 609                 if (da->flags.array) {
 610                         switch (da->type) {
 611                         case PW_TYPE_BYTE:
 612                                 num_entries = alen;
 613                                 alen = 1;
 614                                 break;
 615
 616                         case PW_TYPE_SHORT: /* ignore any trailing data */
 617                                 num_entries = alen >> 1;
 618                                 alen = 2;
 619                                 break;
 620
 621                         case PW_TYPE_IPADDR:
 622                         case PW_TYPE_INTEGER:
 623                         case PW_TYPE_DATE: /* ignore any trailing data */
 624                                 num_entries = alen >> 2;
 625                                 alen = 4;
 626                                 break;
 627
 628                         default:
 629
 630                                 break; /* really an internal sanity failure */
 631                         }
 632                 }
 633
 634                 /*
 635                  *      Loop over all of the entries, building VPs
 636                  */
 637                 for (i = 0; i < num_entries; i++) {
 638                         vp = pairmake(da->name, NULL, T_OP_ADD);
 639                         if (!vp) {
 640                                 fr_strerror_printf("Cannot build attribute %s",
 641                                         fr_strerror());
 642                                 pairfree(head);
 643                                 return -1;
 644                         }
 645
 646                         /*
 647                          *      Hack for ease of use.
 648                          */
 649                         if (fr_dhcp_attr2vp(vp, p, alen) < 0) {
 650                                 pairfree(&vp);
 651                                 pairfree(head);
 652                                 return -1;
 653                         }
 654
 655                         *tail = vp;
 656                         while (*tail) {
 657                                 debug_pair(*tail);
 658                                 tail = &(*tail)->next;
 659                         }
 660                         p += alen;
 661                 } /* loop over array entries */
 662         } /* loop over the entire packet */
 663
 664         return next - data;
 665 }
 666
 667 int fr_dhcp_decode(RADIUS_PACKET *packet)
 668 {
 669         size_t i;
 670         uint8_t *p;
 671         uint32_t giaddr;
 672         VALUE_PAIR *head, *vp, **tail;
 673         VALUE_PAIR *maxms, *mtu;
 674
 675         head = NULL;
 676         tail = &head;
 677         p = packet->data;
 678
 679         if ((fr_debug_flag > 2) && fr_log_fp) {
 680                 for (i = 0; i < packet->data_len; i++) {
 681                         if ((i & 0x0f) == 0x00) fprintf(fr_log_fp, "%d: ", (int) i);
 682                         fprintf(fr_log_fp, "%02x ", packet->data[i]);
 683                         if ((i & 0x0f) == 0x0f) fprintf(fr_log_fp, "\n");
 684                 }
 685                 fprintf(fr_log_fp, "\n");
 686         }
 687
 688         if (packet->data[1] != 1) {
 689                 fr_strerror_printf("Packet is not Ethernet: %u",
 690                       packet->data[1]);
 691                 return -1;
 692         }
 693
 694         /*
 695          *      Decode the header.
 696          */
 697         for (i = 0; i < 14; i++) {
 698                 vp = pairmake(dhcp_header_names[i], NULL, T_OP_EQ);
 699                 if (!vp) {
 700                         char buffer[256];
 701                         strlcpy(buffer, fr_strerror(), sizeof(buffer));
 702                         fr_strerror_printf("Cannot decode packet due to internal error: %s", buffer);
 703                         pairfree(&head);
 704                         return -1;
 705                 }
 706
 707                 if ((i == 11) &&
 708                     (packet->data[1] == 1) &&
 709                     (packet->data[2] != 6)) {
 710                         fr_strerror_printf("chaddr of incorrect length for ethernet");
 711                 }
 712
 713                 switch (vp->da->type) {
 714                 case PW_TYPE_BYTE:
 715                         vp->vp_integer = p[0];
 716                         vp->length = 1;
 717                         break;
 718
 719                 case PW_TYPE_SHORT:
 720                         vp->vp_integer = (p[0] << 8) | p[1];
 721                         vp->length = 2;
 722                         break;
 723
 724                 case PW_TYPE_INTEGER:
 725                         memcpy(&vp->vp_integer, p, 4);
 726                         vp->vp_integer = ntohl(vp->vp_integer);
 727                         vp->length = 4;
 728                         break;
 729
 730                 case PW_TYPE_IPADDR:
 731                         memcpy(&vp->vp_ipaddr, p, 4);
 732                         vp->length = 4;
 733                         break;
 734
 735                 case PW_TYPE_STRING:
 736                         memcpy(vp->vp_strvalue, p, dhcp_header_sizes[i]);
 737                         vp->vp_strvalue[dhcp_header_sizes[i]] = '\0';
 738                         vp->length = strlen(vp->vp_strvalue);
 739                         if (vp->length == 0) {
 740                                 pairfree(&vp);
 741                         }
 742                         break;
 743
 744                 case PW_TYPE_OCTETS:
 745                         memcpy(vp->vp_octets, p, packet->data[2]);
 746                         vp->length = packet->data[2];
 747                         break;
 748
 749                 case PW_TYPE_ETHERNET:
 750                         memcpy(vp->vp_ether, p, sizeof(vp->vp_ether));
 751                         vp->length = sizeof(vp->vp_ether);
 752                         break;
 753
 754                 default:
 755                         fr_strerror_printf("BAD TYPE %d", vp->da->type);
 756                         pairfree(&vp);
 757                         break;
 758                 }
 759                 p += dhcp_header_sizes[i];
 760
 761                 if (!vp) continue;
 762
 763                 debug_pair(vp);
 764                 *tail = vp;
 765                 tail = &vp->next;
 766         }
 767
 768         /*
 769          *      Loop over the options.
 770          */
 771
 772         /*
 773          *  Nothing uses tail after this call, if it does in the future
 774          *  it'll need to find the new tail...
 775          */
 776         if (fr_dhcp_decode_options(packet->data + 240, packet->data_len - 240,
 777                                    tail) < 0) {
 778                 return -1;
 779         }
 780
 781         /*
 782          *      If DHCP request, set ciaddr to zero.
 783          */
 784
 785         /*
 786          *      Set broadcast flag for broken vendors, but only if
 787          *      giaddr isn't set.
 788          */
 789         memcpy(&giaddr, packet->data + 24, sizeof(giaddr));
 790         if (giaddr == htonl(INADDR_ANY)) {
 791                 /*
 792                  *      DHCP Opcode is request
 793                  */
 794                 vp = pairfind(head, 256, DHCP_MAGIC_VENDOR, TAG_ANY);
 795                 if (vp && vp->vp_integer == 3) {
 796                         /*
 797                          *      Vendor is "MSFT 98"
 798                          */
 799                         vp = pairfind(head, 63, DHCP_MAGIC_VENDOR, TAG_ANY);
 800                         if (vp && (strcmp(vp->vp_strvalue, "MSFT 98") == 0)) {
 801                                 vp = pairfind(head, 262, DHCP_MAGIC_VENDOR, TAG_ANY);
 802
 803                                 /*
 804                                  *      Reply should be broadcast.
 805                                  */
 806                                 if (vp) vp->vp_integer |= 0x8000;
 807                                 packet->data[10] |= 0x80;
 808                         }
 809                 }
 810         }
 811
 812         /*
 813          *      FIXME: Nuke attributes that aren't used in the normal
 814          *      header for discover/requests.
 815          */
 816         packet->vps = head;
 817
 818         /*
 819          *      Client can request a LARGER size, but not a smaller
 820          *      one.  They also cannot request a size larger than MTU.
 821          */
 822         maxms = pairfind(packet->vps, 57, DHCP_MAGIC_VENDOR, TAG_ANY);
 823         mtu = pairfind(packet->vps, 26, DHCP_MAGIC_VENDOR, TAG_ANY);
 824
 825         if (mtu && (mtu->vp_integer < DEFAULT_PACKET_SIZE)) {
 826                 fr_strerror_printf("DHCP Fatal: Client says MTU is smaller than minimum permitted by the specification.");
 827                 return -1;
 828         }
 829
 830         if (maxms && (maxms->vp_integer < DEFAULT_PACKET_SIZE)) {
 831                 fr_strerror_printf("DHCP WARNING: Client says maximum message size is smaller than minimum permitted by the specification: fixing it");
 832                 maxms->vp_integer = DEFAULT_PACKET_SIZE;
 833         }
 834
 835         if (maxms && mtu && (maxms->vp_integer > mtu->vp_integer)) {
 836                 fr_strerror_printf("DHCP WARNING: Client says MTU is smaller than maximum message size: fixing it");
 837                 maxms->vp_integer = mtu->vp_integer;
 838         }
 839
 840         if (fr_debug_flag > 0) {
 841                 for (vp = packet->vps; vp != NULL; vp = vp->next) {
 842                         /* Print debug output here? */
 843                 }
 844         }
 845
 846         if (fr_debug_flag) fflush(stdout);
 847
 848         return 0;
 849 }
 850
 851
 852 static int attr_cmp(const void *one, const void *two)
 853 {
 854         const VALUE_PAIR * const *a = one;
 855         const VALUE_PAIR * const *b = two;
 856
 857         /*
 858          *      DHCP-Message-Type is first, for simplicity.
 859          */
 860         if (((*a)->da->attr == 53) &&
 861             (*b)->da->attr != 53) return -1;
 862
 863         /*
 864          *      Relay-Agent is last
 865          */
 866         if (((*a)->da->attr == 82) &&
 867             (*b)->da->attr != 82) return +1;
 868
 869         return ((*a)->da->attr - (*b)->da->attr);
 870 }
 871
 872
 873 static size_t fr_dhcp_vp2attr(VALUE_PAIR *vp, uint8_t *p, size_t room)
 874 {
 875         size_t length;
 876         uint32_t lvalue;
 877
 878         /*
 879          *      FIXME: Check room!
 880          */
 881         room = room;            /* -Wunused */
 882
 883         /*
 884          *      Search for all attributes of the same
 885          *      type, and pack them into the same
 886          *      attribute.
 887          */
 888         switch (vp->da->type) {
 889         case PW_TYPE_BYTE:
 890                 length = 1;
 891                 *p = vp->vp_integer & 0xff;
 892                 break;
 893
 894         case PW_TYPE_SHORT:
 895                 length = 2;
 896                 p[0] = (vp->vp_integer >> 8) & 0xff;
 897                 p[1] = vp->vp_integer & 0xff;
 898                 break;
 899
 900         case PW_TYPE_INTEGER:
 901                 length = 4;
 902                 lvalue = htonl(vp->vp_integer);
 903                 memcpy(p, &lvalue, 4);
 904                 break;
 905
 906         case PW_TYPE_IPADDR:
 907                 length = 4;
 908                 memcpy(p, &vp->vp_ipaddr, 4);
 909                 break;
 910
 911         case PW_TYPE_ETHERNET:
 912                 length = 6;
 913                 memcpy(p, &vp->vp_ether, 6);
 914                 break;
 915
 916         case PW_TYPE_STRING:
 917                 memcpy(p, vp->vp_strvalue, vp->length);
 918                 length = vp->length;
 919                 break;
 920
 921         case PW_TYPE_TLV:       /* FIXME: split it on 255? */
 922                 memcpy(p, vp->vp_tlv, vp->length);
 923                 length = vp->length;
 924                 break;
 925
 926         case PW_TYPE_OCTETS:
 927                 memcpy(p, vp->vp_octets, vp->length);
 928                 length = vp->length;
 929                 break;
 930
 931         default:
 932                 fr_strerror_printf("BAD TYPE2 %d", vp->da->type);
 933                 length = 0;
 934                 break;
 935         }
 936
 937         return length;
 938 }
 939
 940 static VALUE_PAIR *fr_dhcp_vp2suboption(VALUE_PAIR *vps)
 941 {
 942         int length;
 943         unsigned int attribute;
 944         uint8_t *ptr;
 945         VALUE_PAIR *vp, *tlv;
 946
 947         attribute = vps->da->attr & 0xffff00ff;
 948
 949         tlv = paircreate(attribute, DHCP_MAGIC_VENDOR);
 950         if (!tlv) return NULL;
 951
 952         tlv->length = 0;
 953         for (vp = vps; vp != NULL; vp = vp->next) {
 954                 /*
 955                  *      Group the attributes ONLY until we see a
 956                  *      non-TLV attribute.
 957                  */
 958                 if (!vp->da->flags.is_tlv ||
 959                     vp->da->flags.extended ||
 960                     ((vp->da->attr & 0xffff00ff) != attribute)) {
 961                         break;
 962                 }
 963
 964                 tlv->length += vp->length + 2;
 965         }
 966
 967         if (!tlv->length) {
 968                 pairfree(&tlv);
 969                 return NULL;
 970         }
 971
 972         tlv->vp_tlv = malloc(tlv->length);
 973         if (!tlv->vp_tlv) {
 974                 pairfree(&tlv);
 975                 return NULL;
 976         }
 977
 978         ptr = tlv->vp_tlv;
 979         for (vp = vps; vp != NULL; vp = vp->next) {
 980                 if (!vp->da->flags.is_tlv ||
 981                     vp->da->flags.extended ||
 982                     ((vp->da->attr & 0xffff00ff) != attribute)) {
 983                         break;
 984                 }
 985
 986                 length = fr_dhcp_vp2attr(vp, ptr + 2,
 987                                          tlv->vp_tlv + tlv->length - ptr);
 988                 if (length > 255) {
 989                         pairfree(&tlv);
 990                         return NULL;
 991                 }
 992
 993                 /*
 994                  *      Pack the attribute.
 995                  */
 996                 ptr[0] = (vp->da->attr & 0xff00) >> 8;
 997                 ptr[1] = length;
 998
 999                 ptr += length + 2;
1000         }
1001
1002         return tlv;
1003 }
1004
1005
1006 int fr_dhcp_encode(RADIUS_PACKET *packet, RADIUS_PACKET *original)
1007 {
1008         unsigned int i, num_vps;
1009         uint8_t *p;
1010         VALUE_PAIR *vp;
1011         uint32_t lvalue, mms;
1012         size_t dhcp_size, length;
1013         dhcp_packet_t *dhcp;
1014
1015         if (packet->data) return 0;
1016
1017         packet->data = malloc(MAX_PACKET_SIZE);
1018         if (!packet->data) return -1;
1019
1020         packet->data_len = MAX_PACKET_SIZE;
1021
1022         if (packet->code == 0) packet->code = PW_DHCP_NAK;
1023
1024         /*
1025          *      If there's a request, use it as a template.
1026          *      Otherwise, assume that the caller has set up
1027          *      everything appropriately.
1028          */
1029         if (original) {
1030                 packet->dst_ipaddr.af = AF_INET;
1031                 packet->src_ipaddr.af = AF_INET;
1032
1033                 packet->dst_port = original->src_port;
1034                 packet->src_port = original->dst_port;
1035
1036                 /*
1037                  *      Note that for DHCP, we NEVER send the response
1038                  *      to the source IP address of the request.  It
1039                  *      may have traversed multiple relays, and we
1040                  *      need to send the request to the relay closest
1041                  *      to the client.
1042                  *
1043                  *      if giaddr, send to giaddr.
1044                  *      if NAK, send broadcast.
1045                  *      if broadcast flag, send broadcast.
1046                  *      if ciaddr is empty, send broadcast.
1047                  *      otherwise unicast to ciaddr.
1048                  */
1049
1050                 /*
1051                  *      FIXME: alignment issues.  We likely don't want to
1052                  *      de-reference the packet structure directly..
1053                  */
1054                 dhcp = (dhcp_packet_t *) original->data;
1055
1056                 /*
1057                  *      Default to sending it via sendto(), without using
1058                  *      raw sockets.
1059                  */
1060                 packet->offset = 1;
1061
1062                 if (dhcp->giaddr != htonl(INADDR_ANY)) {
1063                         packet->dst_ipaddr.ipaddr.ip4addr.s_addr = dhcp->giaddr;
1064
1065                         if (dhcp->giaddr != htonl(INADDR_LOOPBACK)) {
1066                                 packet->dst_port = original->dst_port;
1067                         } else {
1068                                 packet->dst_port = original->src_port; /* debugging */
1069                         }
1070
1071                 } else if ((packet->code == PW_DHCP_NAK) ||
1072                            ((dhcp->flags & 0x8000) != 0) ||
1073                            (dhcp->ciaddr == htonl(INADDR_ANY))) {
1074                         /*
1075                          *      The kernel will take care of sending it to
1076                          *      the broadcast MAC.
1077                          */
1078                         packet->dst_ipaddr.ipaddr.ip4addr.s_addr = htonl(INADDR_BROADCAST);
1079
1080                 } else {
1081                         /*
1082                          *      It was broadcast to us: we need to
1083                          *      broadcast the response.
1084                          */
1085                         if (packet->src_ipaddr.ipaddr.ip4addr.s_addr != dhcp->ciaddr) {
1086                                 packet->offset = 0;
1087                         }
1088                         packet->dst_ipaddr.ipaddr.ip4addr.s_addr = dhcp->ciaddr;
1089                 }
1090
1091                 /*
1092                  *      Rewrite the source IP to be our own, if we know it.
1093                  */
1094                 if (packet->src_ipaddr.ipaddr.ip4addr.s_addr == htonl(INADDR_BROADCAST)) {
1095                         packet->src_ipaddr.ipaddr.ip4addr.s_addr = htonl(INADDR_ANY);
1096                 }
1097         } else {
1098                 memset(packet->data, 0, packet->data_len);
1099         }
1100
1101         if (fr_debug_flag > 1) {
1102                 char type_buf[64];
1103                 const char *name = type_buf;
1104                 char src_ip_buf[256], dst_ip_buf[256];
1105
1106                 if ((packet->code >= PW_DHCP_DISCOVER) &&
1107                     (packet->code <= PW_DHCP_INFORM)) {
1108                         name = dhcp_message_types[packet->code - PW_DHCP_OFFSET];
1109                 } else {
1110                         snprintf(type_buf, sizeof(type_buf), "%d",
1111                                  packet->code - PW_DHCP_OFFSET);
1112                 }
1113
1114                 DEBUG("Sending %s of id %08x from %s:%d to %s:%d\n",
1115                        name, (unsigned int) packet->id,
1116                        inet_ntop(packet->src_ipaddr.af,
1117                                  &packet->src_ipaddr.ipaddr,
1118                                  src_ip_buf, sizeof(src_ip_buf)),
1119                        packet->src_port,
1120                        inet_ntop(packet->dst_ipaddr.af,
1121                                  &packet->dst_ipaddr.ipaddr,
1122                                  dst_ip_buf, sizeof(dst_ip_buf)),
1123                        packet->dst_port);
1124
1125                 if (fr_debug_flag) {
1126                         for (i = 256; i < 269; i++) {
1127                                 vp = pairfind(packet->vps, i, DHCP_MAGIC_VENDOR, TAG_ANY);
1128                                 if (!vp) continue;
1129
1130                                 debug_pair(vp);
1131                         }
1132                 }
1133         }
1134
1135         p = packet->data;
1136
1137         mms = DEFAULT_PACKET_SIZE; /* maximum message size */
1138
1139         if (original) {
1140                 /*
1141                  *      Clients can request a LARGER size, but not a
1142                  *      smaller one.  They also cannot request a size
1143                  *      larger than MTU.
1144                  */
1145                 vp = pairfind(original->vps, 57, DHCP_MAGIC_VENDOR, TAG_ANY);
1146                 if (vp && (vp->vp_integer > mms)) {
1147                         mms = vp->vp_integer;
1148
1149                         if (mms > MAX_PACKET_SIZE) mms = MAX_PACKET_SIZE;
1150                 }
1151         }
1152
1153         /*
1154          *      RFC 3118: Authentication option.
1155          */
1156         vp = pairfind(packet->vps, 90, DHCP_MAGIC_VENDOR, TAG_ANY);
1157         if (vp) {
1158                 if (vp->length < 2) {
1159                         memset(vp->vp_octets + vp->length, 0,
1160                                2 - vp->length);
1161                         vp->length = 2;
1162                 }
1163
1164                 if (vp->length < 3) {
1165                         struct timeval tv;
1166
1167                         gettimeofday(&tv, NULL);
1168                         vp->vp_octets[2] = 0;
1169                         timeval2ntp(&tv, vp->vp_octets + 3);
1170                         vp->length = 3 + 8;
1171                 }
1172
1173                 /*
1174                  *      Configuration token (clear-text token)
1175                  */
1176                 if (vp->vp_octets[0] == 0) {
1177                         VALUE_PAIR *pass;
1178                         vp->vp_octets[1] = 0;
1179
1180                         pass = pairfind(packet->vps, PW_CLEARTEXT_PASSWORD, DHCP_MAGIC_VENDOR, TAG_ANY);
1181                         if (pass) {
1182                                 length = pass->length;
1183                                 if ((length + 11) > sizeof(vp->vp_octets)) {
1184                                         length -= ((length + 11) - sizeof(vp->vp_octets));
1185                                 }
1186                                 memcpy(vp->vp_octets + 11, pass->vp_strvalue,
1187                                        length);
1188                                 vp->length = length + 11;
1189                         } else {
1190                                 vp->length = 11 + 8;
1191                                 memset(vp->vp_octets + 11, 0, 8);
1192                                 vp->length = 11 + 8;
1193                         }
1194                 } else {        /* we don't support this type! */
1195                         fr_strerror_printf("DHCP-Authentication %d unsupported",
1196                                 vp->vp_octets[0]);
1197                 }
1198         }
1199
1200         vp = pairfind(packet->vps, 256, DHCP_MAGIC_VENDOR, TAG_ANY);
1201         if (vp) {
1202                 *p++ = vp->vp_integer & 0xff;
1203         } else {
1204                 if (!original) {
1205                         *p++ = 1;       /* client message */
1206                 } else {
1207                         *p++ = 2;       /* server message */
1208                 }
1209         }
1210         *p++ = 1;               /* hardware type = ethernet */
1211         *p++ = 6;               /* 6 bytes of ethernet */
1212
1213         vp = pairfind(packet->vps, 259, DHCP_MAGIC_VENDOR, TAG_ANY);
1214         if (vp) {
1215                 *p++ = vp->vp_integer & 0xff;
1216         } else {
1217                 *p++ = 0;               /* hops */
1218         }
1219
1220         if (original) { /* Xid */
1221                 memcpy(p, original->data + 4, 4);
1222         } else {
1223                 lvalue = fr_rand();
1224                 memcpy(p, &lvalue, 4);
1225         }
1226         p += 4;
1227
1228         memset(p, 0, 2);        /* secs are zero */
1229         p += 2;
1230
1231         if (original) {
1232                 memcpy(p, original->data + 10, 6); /* copy flags && ciaddr */
1233         }
1234
1235         /*
1236          *      Allow the admin to set the broadcast flag.
1237          */
1238         vp = pairfind(packet->vps, 262, DHCP_MAGIC_VENDOR, TAG_ANY);
1239         if (vp) {
1240                 p[0] |= (vp->vp_integer & 0xff00) >> 8;
1241                 p[1] |= (vp->vp_integer & 0xff);
1242         }
1243
1244         p += 6;
1245
1246         /*
1247          *      Set client IP address.
1248          */
1249         vp = pairfind(packet->vps, 264, DHCP_MAGIC_VENDOR, TAG_ANY); /* Your IP address */
1250         if (vp) {
1251                 lvalue = vp->vp_ipaddr;
1252         } else {
1253                 lvalue = htonl(INADDR_ANY);
1254         }
1255         memcpy(p, &lvalue, 4);  /* your IP address */
1256         p += 4;
1257
1258         vp = pairfind(packet->vps, 265, DHCP_MAGIC_VENDOR, TAG_ANY); /* server IP address */
1259         if (!vp) vp = pairfind(packet->vps, 54, DHCP_MAGIC_VENDOR, TAG_ANY); /* identifier */
1260         if (vp) {
1261                 lvalue = vp->vp_ipaddr;
1262         } else {
1263                 lvalue = htonl(INADDR_ANY);
1264         }
1265         memcpy(p, &lvalue, 4);  /* Server IP address */
1266         p += 4;
1267
1268         if (original) {
1269                 memcpy(p, original->data + 24, 4); /* copy gateway IP address */
1270         } else {
1271                 vp = pairfind(packet->vps, 266, DHCP_MAGIC_VENDOR, TAG_ANY);
1272                 if (vp) {
1273                         lvalue = vp->vp_ipaddr;
1274                 } else {
1275                         lvalue = htonl(INADDR_NONE);
1276                 }
1277                 memcpy(p, &lvalue, 4);
1278         }
1279         p += 4;
1280
1281         if (original) {
1282                 memcpy(p, original->data + 28, DHCP_CHADDR_LEN);
1283         } else {
1284                 vp = pairfind(packet->vps, 267, DHCP_MAGIC_VENDOR, TAG_ANY);
1285                 if (vp) {
1286                         if (vp->length > DHCP_CHADDR_LEN) {
1287                                 memcpy(p, vp->vp_octets, DHCP_CHADDR_LEN);
1288                         } else {
1289                                 memcpy(p, vp->vp_octets, vp->length);
1290                         }
1291                 }
1292         }
1293         p += DHCP_CHADDR_LEN;
1294
1295         /*
1296          *      Zero our sname && filename fields.
1297          */
1298         memset(p, 0, DHCP_SNAME_LEN + DHCP_FILE_LEN);
1299         p += DHCP_SNAME_LEN;
1300
1301         /*
1302          *      Copy over DHCP-Boot-Filename.
1303          *
1304          *      FIXME: This copy should be delayed until AFTER the options
1305          *      have been processed.  If there are too many options for
1306          *      the packet, then they go into the sname && filename fields.
1307          *      When that happens, the boot filename is passed as an option,
1308          *      instead of being placed verbatim in the filename field.
1309          */
1310         vp = pairfind(packet->vps, 269, DHCP_MAGIC_VENDOR, TAG_ANY);
1311         if (vp) {
1312                 if (vp->length > DHCP_FILE_LEN) {
1313                         memcpy(p, vp->vp_strvalue, DHCP_FILE_LEN);
1314                 } else {
1315                         memcpy(p, vp->vp_strvalue, vp->length);
1316                 }
1317         }
1318         p += DHCP_FILE_LEN;
1319
1320         lvalue = htonl(DHCP_OPTION_MAGIC_NUMBER); /* DHCP magic number */
1321         memcpy(p, &lvalue, 4);
1322         p += 4;
1323
1324         /*
1325          *      Print the header.
1326          */
1327         if (fr_debug_flag > 1) {
1328                 uint8_t *pp = p;
1329
1330                 p = packet->data;
1331
1332                 for (i = 0; i < 14; i++) {
1333                         vp = pairmake(dhcp_header_names[i], NULL, T_OP_EQ);
1334                         if (!vp) {
1335                                 char buffer[256];
1336                                 strlcpy(buffer, fr_strerror(), sizeof(buffer));
1337                                 fr_strerror_printf("Cannot decode packet due to internal error: %s", buffer);
1338                                 return -1;
1339                         }
1340
1341                         switch (vp->da->type) {
1342                         case PW_TYPE_BYTE:
1343                                 vp->vp_integer = p[0];
1344                                 vp->length = 1;
1345                                 break;
1346
1347                         case PW_TYPE_SHORT:
1348                                 vp->vp_integer = (p[0] << 8) | p[1];
1349                                 vp->length = 2;
1350                                 break;
1351
1352                         case PW_TYPE_INTEGER:
1353                                 memcpy(&vp->vp_integer, p, 4);
1354                                 vp->vp_integer = ntohl(vp->vp_integer);
1355                                 vp->length = 4;
1356                                 break;
1357
1358                         case PW_TYPE_IPADDR:
1359                                 memcpy(&vp->vp_ipaddr, p, 4);
1360                                 vp->length = 4;
1361                                 break;
1362
1363                         case PW_TYPE_STRING:
1364                                 memcpy(vp->vp_strvalue, p, dhcp_header_sizes[i]);
1365                                 vp->vp_strvalue[dhcp_header_sizes[i]] = '\0';
1366                                 vp->length = strlen(vp->vp_strvalue);
1367                                 break;
1368
1369                         case PW_TYPE_OCTETS: /* only for Client HW Address */
1370                                 memcpy(vp->vp_octets, p, packet->data[2]);
1371                                 vp->length = packet->data[2];
1372                                 break;
1373
1374                         case PW_TYPE_ETHERNET: /* only for Client HW Address */
1375                                 memcpy(vp->vp_ether, p, sizeof(vp->vp_ether));
1376                                 vp->length = sizeof(vp->vp_ether);
1377                                 break;
1378
1379                         default:
1380                                 fr_strerror_printf("Internal sanity check failed %d %d", vp->da->type, __LINE__);
1381                                 pairfree(&vp);
1382                                 break;
1383                         }
1384
1385                         p += dhcp_header_sizes[i];
1386
1387                         debug_pair(vp);
1388                         pairfree(&vp);
1389                 }
1390
1391                 /*
1392                  *      Jump over DHCP magic number, response, etc.
1393                  */
1394                 p = pp;
1395         }
1396
1397         /*
1398          *      Before packing the attributes, re-order them so that
1399          *      the array ones are all contiguous.  This simplifies
1400          *      the later code.
1401          */
1402         num_vps = 0;
1403         for (vp = packet->vps; vp != NULL; vp = vp->next) {
1404                 num_vps++;
1405         }
1406         if (num_vps > 1) {
1407                 VALUE_PAIR **array, **last;
1408
1409                 array = malloc(num_vps * sizeof(VALUE_PAIR *));
1410
1411                 i = 0;
1412                 for (vp = packet->vps; vp != NULL; vp = vp->next) {
1413                         array[i++] = vp;
1414                 }
1415
1416                 /*
1417                  *      Sort the attributes.
1418                  */
1419                 qsort(array, (size_t) num_vps, sizeof(VALUE_PAIR *),
1420                       attr_cmp);
1421
1422                 last = &packet->vps;
1423                 for (i = 0; i < num_vps; i++) {
1424                         *last = array[i];
1425                         array[i]->next = NULL;
1426                         last = &(array[i]->next);
1427                 }
1428                 free(array);
1429         }
1430
1431         p[0] = 0x35;            /* DHCP-Message-Type */
1432         p[1] = 1;
1433         p[2] = packet->code - PW_DHCP_OFFSET;
1434         p += 3;
1435
1436         /*
1437          *      Pack in the attributes.
1438          */
1439         vp = packet->vps;
1440         while (vp) {
1441                 unsigned int num_entries = 1;
1442                 VALUE_PAIR *same;
1443                 uint8_t *plength;
1444
1445                 if (vp->da->vendor != DHCP_MAGIC_VENDOR) goto next;
1446                 if (vp->da->attr == 53) goto next; /* already done */
1447                 if ((vp->da->attr > 255) &&
1448                     (DHCP_BASE_ATTR(vp->da->attr) != PW_DHCP_OPTION_82)) goto next;
1449
1450                 debug_pair(vp);
1451                 if (vp->da->flags.extended) goto next;
1452
1453                 length = vp->length;
1454
1455                 for (same = vp->next; same != NULL; same = same->next) {
1456                         if (same->da->attr != vp->da->attr) break;
1457                         num_entries++;
1458                 }
1459
1460                 /*
1461                  *      For client-identifier
1462                  * @fixme What's this meant to be doing?!
1463                  */
1464 #if 0
1465                 if ((vp->da->type == PW_TYPE_ETHERNET) &&
1466                     (vp->length == 6) &&
1467                     (num_entries == 1)) {
1468                         vp->da->type = PW_TYPE_OCTETS;
1469                         memmove(vp->vp_octets + 1, vp->vp_octets, 6);
1470                         vp->vp_octets[0] = 1;
1471                 }
1472 #endif
1473                 *(p++) = vp->da->attr & 0xff;
1474                 plength = p;
1475                 *(p++) = 0;     /* header isn't included in attr length */
1476
1477                 for (i = 0; i < num_entries; i++) {
1478                         if (i != 0) debug_pair(vp);
1479
1480                         if (vp->da->flags.is_tlv) {
1481                                 VALUE_PAIR *tlv;
1482
1483                                 /*
1484                                  *      Should NOT have been encoded yet!
1485                                  */
1486                                 tlv = fr_dhcp_vp2suboption(vp);
1487
1488                                 /*
1489                                  *      Ignore it if there's an issue
1490                                  *      encoding it.
1491                                  */
1492                                 if (!tlv) goto next;
1493
1494                                 tlv->next = vp->next;
1495                                 vp->next = tlv;
1496                                 vp = tlv;
1497                         }
1498
1499                         length = fr_dhcp_vp2attr(vp, p, 0);
1500
1501                         /*
1502                          *      This will never happen due to FreeRADIUS
1503                          *      limitations: sizeof(vp->vp_octets) < 255
1504                          */
1505                         if (length > 255) {
1506                                 fr_strerror_printf("WARNING Ignoring too long attribute %s!", vp->da->name);
1507                                 break;
1508                         }
1509
1510                         /*
1511                          *      More than one attribute of the same type
1512                          *      in a row: they are packed together
1513                          *      into the same TLV.  If we overflow,
1514                          *      go bananas!
1515                          */
1516                         if ((*plength + length) > 255) {
1517                                 fr_strerror_printf("WARNING Ignoring too long attribute %s!", vp->da->name);
1518                                 break;
1519                         }
1520
1521                         *plength += length;
1522                         p += length;
1523
1524                         if (vp->next &&
1525                             (vp->next->da->attr == vp->da->attr))
1526                                 vp = vp->next;
1527                 } /* loop over num_entries */
1528
1529         next:
1530                 vp = vp->next;
1531         }
1532
1533         p[0] = 0xff;            /* end of option option */
1534         p[1] = 0x00;
1535         p += 2;
1536         dhcp_size = p - packet->data;
1537
1538         /*
1539          *      FIXME: if (dhcp_size > mms),
1540          *        then we put the extra options into the "sname" and "file"
1541          *        fields, AND set the "end option option" in the "options"
1542          *        field.  We also set the "overload option",
1543          *        and put options into the "file" field, followed by
1544          *        the "sname" field.  Where each option is completely
1545          *        enclosed in the "file" and/or "sname" field, AND
1546          *        followed by the "end of option", and MUST be followed
1547          *        by padding option.
1548          *
1549          *      Yuck.  That sucks...
1550          */
1551         packet->data_len = dhcp_size;
1552
1553         if (original) {
1554                 /*
1555                  *      FIXME: This may set it to broadcast, which we don't
1556                  *      want.  Instead, set it to the real address of the
1557                  *      socket.
1558                  */
1559                 packet->src_ipaddr = original->dst_ipaddr;
1560
1561                 packet->sockfd = original->sockfd;
1562         }
1563
1564         if (packet->data_len < DEFAULT_PACKET_SIZE) {
1565                 memset(packet->data + packet->data_len, 0,
1566                        DEFAULT_PACKET_SIZE - packet->data_len);
1567                 packet->data_len = DEFAULT_PACKET_SIZE;
1568         }
1569
1570         if ((fr_debug_flag > 2) && fr_log_fp) {
1571                 for (i = 0; i < packet->data_len; i++) {
1572                         if ((i & 0x0f) == 0x00) fprintf(fr_log_fp, "%d: ", i);
1573                         fprintf(fr_log_fp, "%02x ", packet->data[i]);
1574                         if ((i & 0x0f) == 0x0f) fprintf(fr_log_fp, "\n");
1575                 }
1576                 fprintf(fr_log_fp, "\n");
1577         }
1578
1579         return 0;
1580 }
1581
1582 int fr_dhcp_add_arp_entry(int fd, const char *interface,
1583                           VALUE_PAIR *macaddr, VALUE_PAIR *ip)
1584 {
1585 #ifdef SIOCSARP
1586         struct sockaddr_in *sin;
1587         struct arpreq req;
1588
1589         if (macaddr->length > sizeof (req.arp_ha.sa_data)) {
1590                 fr_strerror_printf("ERROR: DHCP only supports up to %zu octets "
1591                                    "for Client Hardware Address "
1592                                    "(got %zu octets)\n",
1593                                    sizeof(req.arp_ha.sa_data),
1594                                    macaddr->length);
1595                 return -1;
1596         }
1597
1598         memset(&req, 0, sizeof(req));
1599         sin = (struct sockaddr_in *) &req.arp_pa;
1600         sin->sin_family = AF_INET;
1601         sin->sin_addr.s_addr = ip->vp_ipaddr;
1602         strlcpy(req.arp_dev, interface, sizeof(req.arp_dev));
1603         memcpy(&req.arp_ha.sa_data, macaddr->vp_octets, macaddr->length);
1604
1605         req.arp_flags = ATF_COM;
1606         if (ioctl(fd, SIOCSARP, &req) < 0) {
1607                 fr_strerror_printf("DHCP: Failed to add entry in ARP cache: %s (%d)",
1608                                    strerror(errno), errno);
1609                 return -1;
1610         }
1611
1612         return 0;
1613 #else
1614         fd = fd;                /* -Wunused */
1615         interface = interface;  /* -Wunused */
1616         macaddr = macaddr;      /* -Wunused */
1617         ip = ip;                /* -Wunused */
1618
1619         fr_strerror_printf("Adding ARP entry is unsupported on this system");
1620         return -1;
1621 #endif
1622 }
1623
1624 #endif /* WITH_DHCP */