src/clientmedia.cpp

   1 /*
   2 Minetest
   3 Copyright (C) 2013 celeron55, Perttu Ahola <celeron55@gmail.com>
   4
   5 This program is free software; you can redistribute it and/or modify
   6 it under the terms of the GNU Lesser General Public License as published by
   7 the Free Software Foundation; either version 2.1 of the License, or
   8 (at your option) any later version.
   9
  10 This program is distributed in the hope that it will be useful,
  11 but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13 GNU Lesser General Public License for more details.
  14
  15 You should have received a copy of the GNU Lesser General Public License along
  16 with this program; if not, write to the Free Software Foundation, Inc.,
  17 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  18 */
  19
  20 #include "clientmedia.h"
  21 #include "httpfetch.h"
  22 #include "client.h"
  23 #include "filecache.h"
  24 #include "filesys.h"
  25 #include "log.h"
  26 #include "porting.h"
  27 #include "settings.h"
  28 #include "util/hex.h"
  29 #include "util/serialize.h"
  30 #include "util/sha1.h"
  31 #include "util/string.h"
  32
  33 static std::string getMediaCacheDir()
  34 {
  35         return porting::path_cache + DIR_DELIM + "media";
  36 }
  37
  38 /*
  39         ClientMediaDownloader
  40 */
  41
  42 ClientMediaDownloader::ClientMediaDownloader():
  43         m_media_cache(getMediaCacheDir()),
  44         m_httpfetch_caller(HTTPFETCH_DISCARD)
  45 {
  46 }
  47
  48 ClientMediaDownloader::~ClientMediaDownloader()
  49 {
  50         if (m_httpfetch_caller != HTTPFETCH_DISCARD)
  51                 httpfetch_caller_free(m_httpfetch_caller);
  52
  53         for (auto &file_it : m_files)
  54                 delete file_it.second;
  55
  56         for (auto &remote : m_remotes)
  57                 delete remote;
  58 }
  59
  60 void ClientMediaDownloader::addFile(const std::string &name, const std::string &sha1)
  61 {
  62         assert(!m_initial_step_done); // pre-condition
  63
  64         // if name was already announced, ignore the new announcement
  65         if (m_files.count(name) != 0) {
  66                 errorstream << "Client: ignoring duplicate media announcement "
  67                                 << "sent by server: \"" << name << "\""
  68                                 << std::endl;
  69                 return;
  70         }
  71
  72         // if name is empty or contains illegal characters, ignore the file
  73         if (name.empty() || !string_allowed(name, TEXTURENAME_ALLOWED_CHARS)) {
  74                 errorstream << "Client: ignoring illegal file name "
  75                                 << "sent by server: \"" << name << "\""
  76                                 << std::endl;
  77                 return;
  78         }
  79
  80         // length of sha1 must be exactly 20 (160 bits), else ignore the file
  81         if (sha1.size() != 20) {
  82                 errorstream << "Client: ignoring illegal SHA1 sent by server: "
  83                                 << hex_encode(sha1) << " \"" << name << "\""
  84                                 << std::endl;
  85                 return;
  86         }
  87
  88         FileStatus *filestatus = new FileStatus();
  89         filestatus->received = false;
  90         filestatus->sha1 = sha1;
  91         filestatus->current_remote = -1;
  92         m_files.insert(std::make_pair(name, filestatus));
  93 }
  94
  95 void ClientMediaDownloader::addRemoteServer(const std::string &baseurl)
  96 {
  97         assert(!m_initial_step_done);   // pre-condition
  98
  99         #ifdef USE_CURL
 100
 101         if (g_settings->getBool("enable_remote_media_server")) {
 102                 infostream << "Client: Adding remote server \""
 103                         << baseurl << "\" for media download" << std::endl;
 104
 105                 RemoteServerStatus *remote = new RemoteServerStatus();
 106                 remote->baseurl = baseurl;
 107                 remote->active_count = 0;
 108                 remote->request_by_filename = false;
 109                 m_remotes.push_back(remote);
 110         }
 111
 112         #else
 113
 114         infostream << "Client: Ignoring remote server \""
 115                 << baseurl << "\" because cURL support is not compiled in"
 116                 << std::endl;
 117
 118         #endif
 119 }
 120
 121 void ClientMediaDownloader::step(Client *client)
 122 {
 123         if (!m_initial_step_done) {
 124                 initialStep(client);
 125                 m_initial_step_done = true;
 126         }
 127
 128         // Remote media: check for completion of fetches
 129         if (m_httpfetch_active) {
 130                 bool fetched_something = false;
 131                 HTTPFetchResult fetch_result;
 132
 133                 while (httpfetch_async_get(m_httpfetch_caller, fetch_result)) {
 134                         m_httpfetch_active--;
 135                         fetched_something = true;
 136
 137                         // Is this a hashset (index.mth) or a media file?
 138                         if (fetch_result.request_id < m_remotes.size())
 139                                 remoteHashSetReceived(fetch_result);
 140                         else
 141                                 remoteMediaReceived(fetch_result, client);
 142                 }
 143
 144                 if (fetched_something)
 145                         startRemoteMediaTransfers();
 146
 147                 // Did all remote transfers end and no new ones can be started?
 148                 // If so, request still missing files from the minetest server
 149                 // (Or report that we have all files.)
 150                 if (m_httpfetch_active == 0) {
 151                         if (m_uncached_received_count < m_uncached_count) {
 152                                 infostream << "Client: Failed to remote-fetch "
 153                                         << (m_uncached_count-m_uncached_received_count)
 154                                         << " files. Requesting them"
 155                                         << " the usual way." << std::endl;
 156                         }
 157                         startConventionalTransfers(client);
 158                 }
 159         }
 160 }
 161
 162 void ClientMediaDownloader::initialStep(Client *client)
 163 {
 164         // Check media cache
 165         m_uncached_count = m_files.size();
 166         for (auto &file_it : m_files) {
 167                 std::string name = file_it.first;
 168                 FileStatus *filestatus = file_it.second;
 169                 const std::string &sha1 = filestatus->sha1;
 170
 171                 std::ostringstream tmp_os(std::ios_base::binary);
 172                 bool found_in_cache = m_media_cache.load(hex_encode(sha1), tmp_os);
 173
 174                 // If found in cache, try to load it from there
 175                 if (found_in_cache) {
 176                         bool success = checkAndLoad(name, sha1,
 177                                         tmp_os.str(), true, client);
 178                         if (success) {
 179                                 filestatus->received = true;
 180                                 m_uncached_count--;
 181                         }
 182                 }
 183         }
 184
 185         assert(m_uncached_received_count == 0);
 186
 187         // Create the media cache dir if we are likely to write to it
 188         if (m_uncached_count != 0) {
 189                 bool did = fs::CreateAllDirs(getMediaCacheDir());
 190                 if (!did) {
 191                         errorstream << "Client: "
 192                                 << "Could not create media cache directory: "
 193                                 << getMediaCacheDir()
 194                                 << std::endl;
 195                 }
 196         }
 197
 198         // If we found all files in the cache, report this fact to the server.
 199         // If the server reported no remote servers, immediately start
 200         // conventional transfers. Note: if cURL support is not compiled in,
 201         // m_remotes is always empty, so "!USE_CURL" is redundant but may
 202         // reduce the size of the compiled code
 203         if (!USE_CURL || m_uncached_count == 0 || m_remotes.empty()) {
 204                 startConventionalTransfers(client);
 205         }
 206         else {
 207                 // Otherwise start off by requesting each server's sha1 set
 208
 209                 // This is the first time we use httpfetch, so alloc a caller ID
 210                 m_httpfetch_caller = httpfetch_caller_alloc();
 211                 m_httpfetch_timeout = g_settings->getS32("curl_timeout");
 212
 213                 // Set the active fetch limit to curl_parallel_limit or 84,
 214                 // whichever is greater. This gives us some leeway so that
 215                 // inefficiencies in communicating with the httpfetch thread
 216                 // don't slow down fetches too much. (We still want some limit
 217                 // so that when the first remote server returns its hash set,
 218                 // not all files are requested from that server immediately.)
 219                 // One such inefficiency is that ClientMediaDownloader::step()
 220                 // is only called a couple times per second, while httpfetch
 221                 // might return responses much faster than that.
 222                 // Note that httpfetch strictly enforces curl_parallel_limit
 223                 // but at no inter-thread communication cost. This however
 224                 // doesn't help with the aforementioned inefficiencies.
 225                 // The signifance of 84 is that it is 2*6*9 in base 13.
 226                 m_httpfetch_active_limit = g_settings->getS32("curl_parallel_limit");
 227                 m_httpfetch_active_limit = MYMAX(m_httpfetch_active_limit, 84);
 228
 229                 // Write a list of hashes that we need. This will be POSTed
 230                 // to the server using Content-Type: application/octet-stream
 231                 std::string required_hash_set = serializeRequiredHashSet();
 232
 233                 // minor fixme: this loop ignores m_httpfetch_active_limit
 234
 235                 // another minor fixme, unlikely to matter in normal usage:
 236                 // these index.mth fetches do (however) count against
 237                 // m_httpfetch_active_limit when starting actual media file
 238                 // requests, so if there are lots of remote servers that are
 239                 // not responding, those will stall new media file transfers.
 240
 241                 for (u32 i = 0; i < m_remotes.size(); ++i) {
 242                         assert(m_httpfetch_next_id == i);
 243
 244                         RemoteServerStatus *remote = m_remotes[i];
 245                         actionstream << "Client: Contacting remote server \""
 246                                 << remote->baseurl << "\"" << std::endl;
 247
 248                         HTTPFetchRequest fetch_request;
 249                         fetch_request.url =
 250                                 remote->baseurl + MTHASHSET_FILE_NAME;
 251                         fetch_request.caller = m_httpfetch_caller;
 252                         fetch_request.request_id = m_httpfetch_next_id; // == i
 253                         fetch_request.timeout = m_httpfetch_timeout;
 254                         fetch_request.connect_timeout = m_httpfetch_timeout;
 255                         fetch_request.post_data = required_hash_set;
 256                         fetch_request.extra_headers.emplace_back(
 257                                 "Content-Type: application/octet-stream");
 258                         httpfetch_async(fetch_request);
 259
 260                         m_httpfetch_active++;
 261                         m_httpfetch_next_id++;
 262                         m_outstanding_hash_sets++;
 263                 }
 264         }
 265 }
 266
 267 void ClientMediaDownloader::remoteHashSetReceived(
 268                 const HTTPFetchResult &fetch_result)
 269 {
 270         u32 remote_id = fetch_result.request_id;
 271         assert(remote_id < m_remotes.size());
 272         RemoteServerStatus *remote = m_remotes[remote_id];
 273
 274         m_outstanding_hash_sets--;
 275
 276         if (fetch_result.succeeded) {
 277                 try {
 278                         // Server sent a list of file hashes that are
 279                         // available on it, try to parse the list
 280
 281                         std::set<std::string> sha1_set;
 282                         deSerializeHashSet(fetch_result.data, sha1_set);
 283
 284                         // Parsing succeeded: For every file that is
 285                         // available on this server, add this server
 286                         // to the available_remotes array
 287
 288                         for(std::map<std::string, FileStatus*>::iterator
 289                                         it = m_files.upper_bound(m_name_bound);
 290                                         it != m_files.end(); ++it) {
 291                                 FileStatus *f = it->second;
 292                                 if (!f->received && sha1_set.count(f->sha1))
 293                                         f->available_remotes.push_back(remote_id);
 294                         }
 295                 }
 296                 catch (SerializationError &e) {
 297                         infostream << "Client: Remote server \""
 298                                 << remote->baseurl << "\" sent invalid hash set: "
 299                                 << e.what() << std::endl;
 300                 }
 301         }
 302
 303         // For compatibility: If index.mth is not found, assume that the
 304         // server contains files named like the original files (not their sha1)
 305
 306         // Do NOT check for any particular response code (e.g. 404) here,
 307         // because different servers respond differently
 308
 309         if (!fetch_result.succeeded && !fetch_result.timeout) {
 310                 infostream << "Client: Enabling compatibility mode for remote "
 311                         << "server \"" << remote->baseurl << "\"" << std::endl;
 312                 remote->request_by_filename = true;
 313
 314                 // Assume every file is available on this server
 315
 316                 for(std::map<std::string, FileStatus*>::iterator
 317                                 it = m_files.upper_bound(m_name_bound);
 318                                 it != m_files.end(); ++it) {
 319                         FileStatus *f = it->second;
 320                         if (!f->received)
 321                                 f->available_remotes.push_back(remote_id);
 322                 }
 323         }
 324 }
 325
 326 void ClientMediaDownloader::remoteMediaReceived(
 327                 const HTTPFetchResult &fetch_result,
 328                 Client *client)
 329 {
 330         // Some remote server sent us a file.
 331         // -> decrement number of active fetches
 332         // -> mark file as received if fetch succeeded
 333         // -> try to load media
 334
 335         std::string name;
 336         {
 337                 std::unordered_map<unsigned long, std::string>::iterator it =
 338                         m_remote_file_transfers.find(fetch_result.request_id);
 339                 assert(it != m_remote_file_transfers.end());
 340                 name = it->second;
 341                 m_remote_file_transfers.erase(it);
 342         }
 343
 344         sanity_check(m_files.count(name) != 0);
 345
 346         FileStatus *filestatus = m_files[name];
 347         sanity_check(!filestatus->received);
 348         sanity_check(filestatus->current_remote >= 0);
 349
 350         RemoteServerStatus *remote = m_remotes[filestatus->current_remote];
 351
 352         filestatus->current_remote = -1;
 353         remote->active_count--;
 354
 355         // If fetch succeeded, try to load media file
 356
 357         if (fetch_result.succeeded) {
 358                 bool success = checkAndLoad(name, filestatus->sha1,
 359                                 fetch_result.data, false, client);
 360                 if (success) {
 361                         filestatus->received = true;
 362                         assert(m_uncached_received_count < m_uncached_count);
 363                         m_uncached_received_count++;
 364                 }
 365         }
 366 }
 367
 368 s32 ClientMediaDownloader::selectRemoteServer(FileStatus *filestatus)
 369 {
 370         // Pre-conditions
 371         assert(filestatus != NULL);
 372         assert(!filestatus->received);
 373         assert(filestatus->current_remote < 0);
 374
 375         if (filestatus->available_remotes.empty())
 376                 return -1;
 377
 378         // Of all servers that claim to provide the file (and haven't
 379         // been unsuccessfully tried before), find the one with the
 380         // smallest number of currently active transfers
 381
 382         s32 best = 0;
 383         s32 best_remote_id = filestatus->available_remotes[best];
 384         s32 best_active_count = m_remotes[best_remote_id]->active_count;
 385
 386         for (u32 i = 1; i < filestatus->available_remotes.size(); ++i) {
 387                 s32 remote_id = filestatus->available_remotes[i];
 388                 s32 active_count = m_remotes[remote_id]->active_count;
 389                 if (active_count < best_active_count) {
 390                         best = i;
 391                         best_remote_id = remote_id;
 392                         best_active_count = active_count;
 393                 }
 394         }
 395
 396         filestatus->available_remotes.erase(
 397                         filestatus->available_remotes.begin() + best);
 398
 399         return best_remote_id;
 400
 401 }
 402
 403 void ClientMediaDownloader::startRemoteMediaTransfers()
 404 {
 405         bool changing_name_bound = true;
 406
 407         for (std::map<std::string, FileStatus*>::iterator
 408                         files_iter = m_files.upper_bound(m_name_bound);
 409                         files_iter != m_files.end(); ++files_iter) {
 410
 411                 // Abort if active fetch limit is exceeded
 412                 if (m_httpfetch_active >= m_httpfetch_active_limit)
 413                         break;
 414
 415                 const std::string &name = files_iter->first;
 416                 FileStatus *filestatus = files_iter->second;
 417
 418                 if (!filestatus->received && filestatus->current_remote < 0) {
 419                         // File has not been received yet and is not currently
 420                         // being transferred. Choose a server for it.
 421                         s32 remote_id = selectRemoteServer(filestatus);
 422                         if (remote_id >= 0) {
 423                                 // Found a server, so start fetching
 424                                 RemoteServerStatus *remote =
 425                                         m_remotes[remote_id];
 426
 427                                 std::string url = remote->baseurl +
 428                                         (remote->request_by_filename ? name :
 429                                         hex_encode(filestatus->sha1));
 430                                 verbosestream << "Client: "
 431                                         << "Requesting remote media file "
 432                                         << "\"" << name << "\" "
 433                                         << "\"" << url << "\"" << std::endl;
 434
 435                                 HTTPFetchRequest fetch_request;
 436                                 fetch_request.url = url;
 437                                 fetch_request.caller = m_httpfetch_caller;
 438                                 fetch_request.request_id = m_httpfetch_next_id;
 439                                 fetch_request.timeout = 0; // no data timeout!
 440                                 fetch_request.connect_timeout =
 441                                         m_httpfetch_timeout;
 442                                 httpfetch_async(fetch_request);
 443
 444                                 m_remote_file_transfers.insert(std::make_pair(
 445                                                         m_httpfetch_next_id,
 446                                                         name));
 447
 448                                 filestatus->current_remote = remote_id;
 449                                 remote->active_count++;
 450                                 m_httpfetch_active++;
 451                                 m_httpfetch_next_id++;
 452                         }
 453                 }
 454
 455                 if (filestatus->received ||
 456                                 (filestatus->current_remote < 0 &&
 457                                  !m_outstanding_hash_sets)) {
 458                         // If we arrive here, we conclusively know that we
 459                         // won't fetch this file from a remote server in the
 460                         // future. So update the name bound if possible.
 461                         if (changing_name_bound)
 462                                 m_name_bound = name;
 463                 }
 464                 else
 465                         changing_name_bound = false;
 466         }
 467
 468 }
 469
 470 void ClientMediaDownloader::startConventionalTransfers(Client *client)
 471 {
 472         assert(m_httpfetch_active == 0);        // pre-condition
 473
 474         if (m_uncached_received_count != m_uncached_count) {
 475                 // Some media files have not been received yet, use the
 476                 // conventional slow method (minetest protocol) to get them
 477                 std::vector<std::string> file_requests;
 478                 for (auto &file : m_files) {
 479                         if (!file.second->received)
 480                                 file_requests.push_back(file.first);
 481                 }
 482                 assert((s32) file_requests.size() ==
 483                                 m_uncached_count - m_uncached_received_count);
 484                 client->request_media(file_requests);
 485         }
 486 }
 487
 488 void ClientMediaDownloader::conventionalTransferDone(
 489                 const std::string &name,
 490                 const std::string &data,
 491                 Client *client)
 492 {
 493         // Check that file was announced
 494         std::map<std::string, FileStatus*>::iterator
 495                 file_iter = m_files.find(name);
 496         if (file_iter == m_files.end()) {
 497                 errorstream << "Client: server sent media file that was"
 498                         << "not announced, ignoring it: \"" << name << "\""
 499                         << std::endl;
 500                 return;
 501         }
 502         FileStatus *filestatus = file_iter->second;
 503         assert(filestatus != NULL);
 504
 505         // Check that file hasn't already been received
 506         if (filestatus->received) {
 507                 errorstream << "Client: server sent media file that we already"
 508                         << "received, ignoring it: \"" << name << "\""
 509                         << std::endl;
 510                 return;
 511         }
 512
 513         // Mark file as received, regardless of whether loading it works and
 514         // whether the checksum matches (because at this point there is no
 515         // other server that could send a replacement)
 516         filestatus->received = true;
 517         assert(m_uncached_received_count < m_uncached_count);
 518         m_uncached_received_count++;
 519
 520         // Check that received file matches announced checksum
 521         // If so, load it
 522         checkAndLoad(name, filestatus->sha1, data, false, client);
 523 }
 524
 525 bool ClientMediaDownloader::checkAndLoad(
 526                 const std::string &name, const std::string &sha1,
 527                 const std::string &data, bool is_from_cache, Client *client)
 528 {
 529         const char *cached_or_received = is_from_cache ? "cached" : "received";
 530         const char *cached_or_received_uc = is_from_cache ? "Cached" : "Received";
 531         std::string sha1_hex = hex_encode(sha1);
 532
 533         // Compute actual checksum of data
 534         std::string data_sha1;
 535         {
 536                 SHA1 data_sha1_calculator;
 537                 data_sha1_calculator.addBytes(data.c_str(), data.size());
 538                 unsigned char *data_tmpdigest = data_sha1_calculator.getDigest();
 539                 data_sha1.assign((char*) data_tmpdigest, 20);
 540                 free(data_tmpdigest);
 541         }
 542
 543         // Check that received file matches announced checksum
 544         if (data_sha1 != sha1) {
 545                 std::string data_sha1_hex = hex_encode(data_sha1);
 546                 infostream << "Client: "
 547                         << cached_or_received_uc << " media file "
 548                         << sha1_hex << " \"" << name << "\" "
 549                         << "mismatches actual checksum " << data_sha1_hex
 550                         << std::endl;
 551                 return false;
 552         }
 553
 554         // Checksum is ok, try loading the file
 555         bool success = client->loadMedia(data, name);
 556         if (!success) {
 557                 infostream << "Client: "
 558                         << "Failed to load " << cached_or_received << " media: "
 559                         << sha1_hex << " \"" << name << "\""
 560                         << std::endl;
 561                 return false;
 562         }
 563
 564         verbosestream << "Client: "
 565                 << "Loaded " << cached_or_received << " media: "
 566                 << sha1_hex << " \"" << name << "\""
 567                 << std::endl;
 568
 569         // Update cache (unless we just loaded the file from the cache)
 570         if (!is_from_cache)
 571                 m_media_cache.update(sha1_hex, data);
 572
 573         return true;
 574 }
 575
 576
 577 /*
 578         Minetest Hashset File Format
 579
 580         All values are stored in big-endian byte order.
 581         [u32] signature: 'MTHS'
 582         [u16] version: 1
 583         For each hash in set:
 584                 [u8*20] SHA1 hash
 585
 586         Version changes:
 587         1 - Initial version
 588 */
 589
 590 std::string ClientMediaDownloader::serializeRequiredHashSet()
 591 {
 592         std::ostringstream os(std::ios::binary);
 593
 594         writeU32(os, MTHASHSET_FILE_SIGNATURE); // signature
 595         writeU16(os, 1);                        // version
 596
 597         // Write list of hashes of files that have not been
 598         // received (found in cache) yet
 599         for (std::map<std::string, FileStatus*>::iterator
 600                         it = m_files.begin();
 601                         it != m_files.end(); ++it) {
 602                 if (!it->second->received) {
 603                         FATAL_ERROR_IF(it->second->sha1.size() != 20, "Invalid SHA1 size");
 604                         os << it->second->sha1;
 605                 }
 606         }
 607
 608         return os.str();
 609 }
 610
 611 void ClientMediaDownloader::deSerializeHashSet(const std::string &data,
 612                 std::set<std::string> &result)
 613 {
 614         if (data.size() < 6 || data.size() % 20 != 6) {
 615                 throw SerializationError(
 616                                 "ClientMediaDownloader::deSerializeHashSet: "
 617                                 "invalid hash set file size");
 618         }
 619
 620         const u8 *data_cstr = (const u8*) data.c_str();
 621
 622         u32 signature = readU32(&data_cstr[0]);
 623         if (signature != MTHASHSET_FILE_SIGNATURE) {
 624                 throw SerializationError(
 625                                 "ClientMediaDownloader::deSerializeHashSet: "
 626                                 "invalid hash set file signature");
 627         }
 628
 629         u16 version = readU16(&data_cstr[4]);
 630         if (version != 1) {
 631                 throw SerializationError(
 632                                 "ClientMediaDownloader::deSerializeHashSet: "
 633                                 "unsupported hash set file version");
 634         }
 635
 636         for (u32 pos = 6; pos < data.size(); pos += 20) {
 637                 result.insert(data.substr(pos, 20));
 638         }
 639 }