src/libcharon/encoding/generator.c

   1 /*
   2  * Copyright (C) 2005-2009 Martin Willi
   3  * Copyright (C) 2005 Jan Hutter
   4  * Hochschule fuer Technik Rapperswil
   5  *
   6  * This program is free software; you can redistribute it and/or modify it
   7  * under the terms of the GNU General Public License as published by the
   8  * Free Software Foundation; either version 2 of the License, or (at your
   9  * option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.
  10  *
  11  * This program is distributed in the hope that it will be useful, but
  12  * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  13  * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * for more details.
  15  */
  16
  17 #include <stdlib.h>
  18 #include <string.h>
  19 #include <arpa/inet.h>
  20 #include <stdio.h>
  21
  22 #include "generator.h"
  23
  24 #include <library.h>
  25 #include <daemon.h>
  26 #include <utils/linked_list.h>
  27 #include <encoding/payloads/payload.h>
  28 #include <encoding/payloads/proposal_substructure.h>
  29 #include <encoding/payloads/transform_substructure.h>
  30 #include <encoding/payloads/sa_payload.h>
  31 #include <encoding/payloads/ke_payload.h>
  32 #include <encoding/payloads/notify_payload.h>
  33 #include <encoding/payloads/nonce_payload.h>
  34 #include <encoding/payloads/id_payload.h>
  35 #include <encoding/payloads/auth_payload.h>
  36 #include <encoding/payloads/cert_payload.h>
  37 #include <encoding/payloads/certreq_payload.h>
  38 #include <encoding/payloads/ts_payload.h>
  39 #include <encoding/payloads/delete_payload.h>
  40 #include <encoding/payloads/vendor_id_payload.h>
  41 #include <encoding/payloads/cp_payload.h>
  42 #include <encoding/payloads/configuration_attribute.h>
  43 #include <encoding/payloads/eap_payload.h>
  44 #include <encoding/payloads/unknown_payload.h>
  45
  46 /**
  47  * Generating is done in a data buffer.
  48  * This is the start size of this buffer in bytes.
  49  */
  50 #define GENERATOR_DATA_BUFFER_SIZE 500
  51
  52 /**
  53  * Number of bytes to increase the buffer, if it is too small.
  54  */
  55 #define GENERATOR_DATA_BUFFER_INCREASE_VALUE 500
  56
  57 typedef struct private_generator_t private_generator_t;
  58
  59 /**
  60  * Private part of a generator_t object.
  61  */
  62 struct private_generator_t {
  63         /**
  64          * Public part of a generator_t object.
  65          */
  66          generator_t public;
  67
  68         /**
  69          * Buffer used to generate the data into.
  70          */
  71         u_int8_t *buffer;
  72
  73         /**
  74          * Current write position in buffer (one byte aligned).
  75          */
  76         u_int8_t *out_position;
  77
  78         /**
  79          * Position of last byte in buffer.
  80          */
  81         u_int8_t *roof_position;
  82
  83         /**
  84          * Current bit writing to in current byte (between 0 and 7).
  85          */
  86         u_int8_t current_bit;
  87
  88         /**
  89          * Associated data struct to read informations from.
  90          */
  91         void *data_struct;
  92
  93         /**
  94          * Offset of the header length field in the buffer.
  95          */
  96         u_int32_t header_length_offset;
  97
  98         /**
  99          * Attribute format of the last generated transform attribute.
 100          *
 101          * Used to check if a variable value field is used or not for
 102          * the transform attribute value.
 103          */
 104         bool attribute_format;
 105
 106         /**
 107          * Depending on the value of attribute_format this field is used
 108          * to hold the length of the transform attribute in bytes.
 109          */
 110         u_int16_t attribute_length;
 111 };
 112
 113 /**
 114  * Get size of current buffer in bytes.
 115  */
 116 static int get_size(private_generator_t *this)
 117 {
 118         return this->roof_position - this->buffer;
 119 }
 120
 121 /**
 122  * Get free space of current buffer in bytes.
 123  */
 124 static int get_space(private_generator_t *this)
 125 {
 126         return this->roof_position - this->out_position;
 127 }
 128
 129 /**
 130  * Get length of data in buffer (in bytes).
 131  */
 132 static int get_length(private_generator_t *this)
 133 {
 134         return this->out_position - this->buffer;
 135 }
 136
 137 /**
 138  * Get current offset in buffer (in bytes).
 139  */
 140 static u_int32_t get_offset(private_generator_t *this)
 141 {
 142         return this->out_position - this->buffer;
 143 }
 144
 145 /**
 146  * Makes sure enough space is available in buffer to store amount of bits.
 147  */
 148 static void make_space_available(private_generator_t *this, int bits)
 149 {
 150         while ((get_space(this) * 8 - this->current_bit) < bits)
 151         {
 152                 int old_buffer_size, new_buffer_size, out_position_offset;
 153
 154                 old_buffer_size = get_size(this);
 155                 new_buffer_size = old_buffer_size + GENERATOR_DATA_BUFFER_INCREASE_VALUE;
 156                 out_position_offset = this->out_position - this->buffer;
 157
 158                 DBG2(DBG_ENC, "increasing gen buffer from %d to %d byte",
 159                          old_buffer_size, new_buffer_size);
 160
 161                 this->buffer = realloc(this->buffer,new_buffer_size);
 162                 this->out_position = (this->buffer + out_position_offset);
 163                 this->roof_position = (this->buffer + new_buffer_size);
 164         }
 165 }
 166
 167 /**
 168  * Writes a specific amount of byte into the buffer.
 169  */
 170 static void write_bytes_to_buffer(private_generator_t *this, void *bytes,
 171                                                                   int number_of_bytes)
 172 {
 173         int i;
 174         u_int8_t *read_position = (u_int8_t *)bytes;
 175
 176         make_space_available(this, number_of_bytes * 8);
 177
 178         for (i = 0; i < number_of_bytes; i++)
 179         {
 180                 *(this->out_position) = *(read_position);
 181                 read_position++;
 182                 this->out_position++;
 183         }
 184 }
 185
 186 /**
 187  * Generates a U_INT-Field type and writes it to buffer.
 188  */
 189 static void generate_u_int_type(private_generator_t *this,
 190                                                                 encoding_type_t int_type,u_int32_t offset)
 191 {
 192         int number_of_bits = 0;
 193
 194         /* find out number of bits of each U_INT type to check for enough space */
 195         switch (int_type)
 196         {
 197                 case U_INT_4:
 198                         number_of_bits = 4;
 199                         break;
 200                 case TS_TYPE:
 201                 case RESERVED_BYTE:
 202                 case SPI_SIZE:
 203                 case U_INT_8:
 204                         number_of_bits = 8;
 205                         break;
 206                 case U_INT_16:
 207                 case PAYLOAD_LENGTH:
 208                 case CONFIGURATION_ATTRIBUTE_LENGTH:
 209                         number_of_bits = 16;
 210                         break;
 211                 case U_INT_32:
 212                         number_of_bits = 32;
 213                         break;
 214                 case ATTRIBUTE_TYPE:
 215                         number_of_bits = 15;
 216                         break;
 217                 case IKE_SPI:
 218                         number_of_bits = 64;
 219                         break;
 220                 default:
 221                         DBG1(DBG_ENC, "U_INT Type %N is not supported",
 222                                  encoding_type_names, int_type);
 223                         return;
 224         }
 225         if ((number_of_bits % 8) == 0 && this->current_bit != 0)
 226         {
 227                 DBG1(DBG_ENC, "U_INT Type %N is not 8 Bit aligned",
 228                          encoding_type_names, int_type);
 229                 return;
 230         }
 231
 232         make_space_available(this, number_of_bits);
 233         switch (int_type)
 234         {
 235                 case U_INT_4:
 236                 {
 237                         u_int8_t high, low;
 238
 239                         if (this->current_bit == 0)
 240                         {
 241                                 /* high of current byte in buffer has to be set to the new value*/
 242                                 high = *((u_int8_t *)(this->data_struct + offset)) << 4;
 243                                 /* low in buffer is not changed */
 244                                 low = *(this->out_position) & 0x0F;
 245                                 /* high is set, low_val is not changed */
 246                                 *(this->out_position) = high | low;
 247                                 DBG3(DBG_ENC, "   => %d", *(this->out_position));
 248                                 /* write position is not changed, just bit position is moved */
 249                                 this->current_bit = 4;
 250                         }
 251                         else if (this->current_bit == 4)
 252                         {
 253                                 /* high in buffer is not changed */
 254                                 high = *(this->out_position) & 0xF0;
 255                                 /* low of current byte in buffer has to be set to the new value*/
 256                                 low = *((u_int8_t *)(this->data_struct + offset)) & 0x0F;
 257                                 *(this->out_position) = high | low;
 258                                 DBG3(DBG_ENC, "   => %d", *(this->out_position));
 259                                 this->out_position++;
 260                                 this->current_bit = 0;
 261                         }
 262                         else
 263                         {
 264                                 DBG1(DBG_ENC, "U_INT_4 Type is not 4 Bit aligned");
 265                                 /* 4 Bit integers must have a 4 bit alignment */
 266                                 return;
 267                         }
 268                         break;
 269                 }
 270                 case TS_TYPE:
 271                 case RESERVED_BYTE:
 272                 case SPI_SIZE:
 273                 case U_INT_8:
 274                 {
 275                         /* 8 bit values are written as they are */
 276                         *this->out_position = *((u_int8_t *)(this->data_struct + offset));
 277                         DBG3(DBG_ENC, "   => %d", *(this->out_position));
 278                         this->out_position++;
 279                         break;
 280                 }
 281                 case ATTRIBUTE_TYPE:
 282                 {
 283                         u_int8_t attribute_format_flag;
 284                         u_int16_t val;
 285
 286                         /* attribute type must not change first bit of current byte */
 287                         if (this->current_bit != 1)
 288                         {
 289                                 DBG1(DBG_ENC, "ATTRIBUTE FORMAT flag is not set");
 290                                 return;
 291                         }
 292                         attribute_format_flag = *(this->out_position) & 0x80;
 293                         /* get attribute type value as 16 bit integer*/
 294                         val = *((u_int16_t*)(this->data_struct + offset));
 295                         /* unset most significant bit */
 296                         val &= 0x7FFF;
 297                         if (attribute_format_flag)
 298                         {
 299                                 val |= 0x8000;
 300                         }
 301                         val = htons(val);
 302                         DBG3(DBG_ENC, "   => %d", val);
 303                         /* write bytes to buffer (set bit is overwritten) */
 304                         write_bytes_to_buffer(this, &val, sizeof(u_int16_t));
 305                         this->current_bit = 0;
 306                         break;
 307
 308                 }
 309                 case U_INT_16:
 310                 case PAYLOAD_LENGTH:
 311                 case CONFIGURATION_ATTRIBUTE_LENGTH:
 312                 {
 313                         u_int16_t val = htons(*((u_int16_t*)(this->data_struct + offset)));
 314                         DBG3(DBG_ENC, "   => %b", &val, sizeof(u_int16_t));
 315                         write_bytes_to_buffer(this, &val, sizeof(u_int16_t));
 316                         break;
 317                 }
 318                 case U_INT_32:
 319                 {
 320                         u_int32_t val = htonl(*((u_int32_t*)(this->data_struct + offset)));
 321                         DBG3(DBG_ENC, "   => %b", &val, sizeof(u_int32_t));
 322                         write_bytes_to_buffer(this, &val, sizeof(u_int32_t));
 323                         break;
 324                 }
 325                 case IKE_SPI:
 326                 {
 327                         /* 64 bit are written as-is, no host order conversion */
 328                         write_bytes_to_buffer(this, this->data_struct + offset,
 329                                                                   sizeof(u_int64_t));
 330                         DBG3(DBG_ENC, "   => %b", this->data_struct + offset,
 331                                  sizeof(u_int64_t));
 332                         break;
 333                 }
 334                 default:
 335                 {
 336                         DBG1(DBG_ENC, "U_INT Type %N is not supported",
 337                                  encoding_type_names, int_type);
 338                         return;
 339                 }
 340         }
 341 }
 342
 343 /**
 344  * Generate a FLAG filed
 345  */
 346 static void generate_flag(private_generator_t *this, u_int32_t offset)
 347 {
 348         u_int8_t flag_value;
 349         u_int8_t flag;
 350
 351         flag_value = (*((bool *) (this->data_struct + offset))) ? 1 : 0;
 352         /* get flag position */
 353         flag = (flag_value << (7 - this->current_bit));
 354
 355         /* make sure one bit is available in buffer */
 356         make_space_available(this, 1);
 357         if (this->current_bit == 0)
 358         {
 359                 /* memory must be zero */
 360                 *(this->out_position) = 0x00;
 361         }
 362
 363         *(this->out_position) = *(this->out_position) | flag;
 364         DBG3(DBG_ENC, "   => %d", *this->out_position);
 365
 366         this->current_bit++;
 367         if (this->current_bit >= 8)
 368         {
 369                 this->current_bit = this->current_bit % 8;
 370                 this->out_position++;
 371         }
 372 }
 373
 374 /**
 375  * Generates a bytestream from a chunk_t.
 376  */
 377 static void generate_from_chunk(private_generator_t *this, u_int32_t offset)
 378 {
 379         chunk_t *value;
 380
 381         if (this->current_bit != 0)
 382         {
 383                 DBG1(DBG_ENC, "can not generate a chunk at Bitpos %d", this->current_bit);
 384                 return ;
 385         }
 386
 387         value = (chunk_t *)(this->data_struct + offset);
 388         DBG3(DBG_ENC, "   => %B", value);
 389
 390         write_bytes_to_buffer(this, value->ptr, value->len);
 391 }
 392
 393 METHOD(generator_t, get_chunk, chunk_t,
 394         private_generator_t *this, u_int32_t **lenpos)
 395 {
 396         chunk_t data;
 397
 398         *lenpos = (u_int32_t*)(this->buffer + this->header_length_offset);
 399         data = chunk_create(this->buffer, get_length(this));
 400         DBG3(DBG_ENC, "generated data of this generator %B", &data);
 401         return data;
 402 }
 403
 404 METHOD(generator_t, generate_payload, void,
 405         private_generator_t *this,payload_t *payload)
 406 {
 407         int i, offset_start, rule_count;
 408         encoding_rule_t *rules;
 409         payload_type_t payload_type;
 410
 411         this->data_struct = payload;
 412         payload_type = payload->get_type(payload);
 413
 414         offset_start = this->out_position - this->buffer;
 415
 416         DBG2(DBG_ENC, "generating payload of type %N",
 417                  payload_type_names, payload_type);
 418
 419         /* each payload has its own encoding rules */
 420         rule_count = payload->get_encoding_rules(payload, &rules);
 421
 422         for (i = 0; i < rule_count;i++)
 423         {
 424                 DBG2(DBG_ENC, "  generating rule %d %N",
 425                          i, encoding_type_names, rules[i].type);
 426                 switch (rules[i].type)
 427                 {
 428                         case U_INT_4:
 429                         case U_INT_8:
 430                         case U_INT_16:
 431                         case U_INT_32:
 432                         case PAYLOAD_LENGTH:
 433                         case IKE_SPI:
 434                         case RESERVED_BYTE:
 435                         case SPI_SIZE:
 436                         case TS_TYPE:
 437                         case ATTRIBUTE_TYPE:
 438                         case CONFIGURATION_ATTRIBUTE_LENGTH:
 439                                 generate_u_int_type(this, rules[i].type, rules[i].offset);
 440                                 break;
 441                         case RESERVED_BIT:
 442                         case FLAG:
 443                                 generate_flag(this, rules[i].offset);
 444                                 break;
 445                         case HEADER_LENGTH:
 446                                 this->header_length_offset = get_offset(this);
 447                                 generate_u_int_type(this, U_INT_32, rules[i].offset);
 448                                 break;
 449                         case ADDRESS:
 450                         case SPI:
 451                         case KEY_EXCHANGE_DATA:
 452                         case KEY_EXCHANGE_DATA_V1:
 453                         case NOTIFICATION_DATA:
 454                         case NONCE_DATA:
 455                         case ID_DATA:
 456                         case AUTH_DATA:
 457                         case CERT_DATA:
 458                         case CERTREQ_DATA:
 459                         case SPIS:
 460                         case CONFIGURATION_ATTRIBUTE_VALUE:
 461                         case VID_DATA:
 462                         case EAP_DATA:
 463                         case ENCRYPTED_DATA:
 464                         case UNKNOWN_DATA:
 465                                 generate_from_chunk(this, rules[i].offset);
 466                                 break;
 467                         case PROPOSALS:
 468                         case PROPOSALS_V1:
 469                         case TRANSFORMS:
 470                         case TRANSFORMS_V1:
 471                         case TRANSFORM_ATTRIBUTES:
 472                         case TRANSFORM_ATTRIBUTES_V1:
 473                         case CONFIGURATION_ATTRIBUTES:
 474                         case TRAFFIC_SELECTORS:
 475                         {
 476                                 linked_list_t *proposals;
 477                                 enumerator_t *enumerator;
 478                                 payload_t *proposal;
 479
 480                                 proposals = *((linked_list_t **)
 481                                                                                 (this->data_struct + rules[i].offset));
 482                                 enumerator = proposals->create_enumerator(proposals);
 483                                 while (enumerator->enumerate(enumerator, &proposal))
 484                                 {
 485                                         generate_payload(this, proposal);
 486                                 }
 487                                 enumerator->destroy(enumerator);
 488                                 break;
 489                         }
 490                         case ATTRIBUTE_FORMAT:
 491                                 generate_flag(this, rules[i].offset);
 492                                 /* Attribute format is a flag which is stored in context*/
 493                                 this->attribute_format =
 494                                                         *((bool *)(this->data_struct + rules[i].offset));
 495                                 break;
 496                         case ATTRIBUTE_LENGTH_OR_VALUE:
 497                                 if (this->attribute_format)
 498                                 {
 499                                         generate_u_int_type(this, U_INT_16, rules[i].offset);
 500                                 }
 501                                 else
 502                                 {
 503                                         generate_u_int_type(this, U_INT_16, rules[i].offset);
 504                                         /* this field hold the length of the attribute */
 505                                         this->attribute_length =
 506                                                 *((u_int16_t *)(this->data_struct + rules[i].offset));
 507                                 }
 508                                 break;
 509                         case ATTRIBUTE_VALUE:
 510                         {
 511                                 if (!this->attribute_format)
 512                                 {
 513                                         DBG2(DBG_ENC, "attribute value has not fixed size");
 514                                         /* the attribute value is generated */
 515                                         generate_from_chunk(this, rules[i].offset);
 516                                 }
 517                                 break;
 518                         }
 519                         default:
 520                                 DBG1(DBG_ENC, "field type %N is not supported",
 521                                          encoding_type_names, rules[i].type);
 522                                 return;
 523                 }
 524         }
 525         DBG2(DBG_ENC, "generating %N payload finished",
 526                  payload_type_names, payload_type);
 527         DBG3(DBG_ENC, "generated data for this payload %b",
 528                  this->buffer + offset_start,
 529                  this->out_position - this->buffer - offset_start);
 530 }
 531
 532 METHOD(generator_t, destroy, void,
 533         private_generator_t *this)
 534 {
 535         free(this->buffer);
 536         free(this);
 537 }
 538
 539 /*
 540  * Described in header
 541  */
 542 generator_t *generator_create()
 543 {
 544         private_generator_t *this;
 545
 546         INIT(this,
 547                 .public = {
 548                         .get_chunk = _get_chunk,
 549                         .generate_payload = _generate_payload,
 550                         .destroy = _destroy,
 551                 },
 552                 .buffer = malloc(GENERATOR_DATA_BUFFER_SIZE),
 553         );
 554
 555         this->out_position = this->buffer;
 556         this->roof_position = this->buffer + GENERATOR_DATA_BUFFER_SIZE;
 557
 558         return &this->public;
 559 }
 560