git.sesse.net Git - cubemap/blob - server.cpp

   1 #include <assert.h>
   2 #include <errno.h>
   3 #include <netinet/in.h>
   4 #include <pthread.h>
   5 #include <stdint.h>
   6 #include <stdio.h>
   7 #include <stdlib.h>
   8 #include <string.h>
   9 #include <sys/epoll.h>
  10 #include <sys/sendfile.h>
  11 #include <sys/socket.h>
  12 #include <sys/types.h>
  13 #include <unistd.h>
  14 #include <algorithm>
  15 #include <map>
  16 #include <string>
  17 #include <utility>
  18 #include <vector>
  19
  20 #include "accesslog.h"
  21 #include "log.h"
  22 #include "markpool.h"
  23 #include "metacube.h"
  24 #include "mutexlock.h"
  25 #include "parse.h"
  26 #include "server.h"
  27 #include "state.pb.h"
  28 #include "stream.h"
  29 #include "util.h"
  30
  31 using namespace std;
  32
  33 extern AccessLogThread *access_log;
  34
  35 Server::Server()
  36 {
  37         pthread_mutex_init(&mutex, NULL);
  38         pthread_mutex_init(&queued_data_mutex, NULL);
  39
  40         epoll_fd = epoll_create(1024);  // Size argument is ignored.
  41         if (epoll_fd == -1) {
  42                 log_perror("epoll_fd");
  43                 exit(1);
  44         }
  45 }
  46
  47 Server::~Server()
  48 {
  49         for (size_t i = 0; i < streams.size(); ++i) {
  50                 delete streams[i];
  51         }
  52
  53         safe_close(epoll_fd);
  54 }
  55
  56 vector<ClientStats> Server::get_client_stats() const
  57 {
  58         vector<ClientStats> ret;
  59
  60         MutexLock lock(&mutex);
  61         for (map<int, Client>::const_iterator client_it = clients.begin();
  62              client_it != clients.end();
  63              ++client_it) {
  64                 ret.push_back(client_it->second.get_stats());
  65         }
  66         return ret;
  67 }
  68
  69 void Server::do_work()
  70 {
  71         while (!should_stop()) {
  72                 // Wait until there's activity on at least one of the fds,
  73                 // or 20 ms (about one frame at 50 fps) has elapsed.
  74                 //
  75                 // We could in theory wait forever and rely on wakeup()
  76                 // from add_client_deferred() and add_data_deferred(),
  77                 // but wakeup is a pretty expensive operation, and the
  78                 // two threads might end up fighting over a lock, so it's
  79                 // seemingly (much) more efficient to just have a timeout here.
  80                 int nfds = epoll_pwait(epoll_fd, events, EPOLL_MAX_EVENTS, EPOLL_TIMEOUT_MS, &sigset_without_usr1_block);
  81                 if (nfds == -1 && errno != EINTR) {
  82                         log_perror("epoll_wait");
  83                         exit(1);
  84                 }
  85
  86                 MutexLock lock(&mutex);  // We release the mutex between iterations.
  87
  88                 process_queued_data();
  89
  90                 for (int i = 0; i < nfds; ++i) {
  91                         Client *client = reinterpret_cast<Client *>(events[i].data.u64);
  92
  93                         if (events[i].events & (EPOLLERR | EPOLLRDHUP | EPOLLHUP)) {
  94                                 close_client(client);
  95                                 continue;
  96                         }
  97
  98                         process_client(client);
  99                 }
 100
 101                 for (size_t i = 0; i < streams.size(); ++i) {
 102                         vector<Client *> to_process;
 103                         swap(streams[i]->to_process, to_process);
 104                         for (size_t i = 0; i < to_process.size(); ++i) {
 105                                 process_client(to_process[i]);
 106                         }
 107                 }
 108         }
 109 }
 110
 111 CubemapStateProto Server::serialize()
 112 {
 113         // We don't serialize anything queued, so empty the queues.
 114         process_queued_data();
 115
 116         // Set all clients in a consistent state before serializing
 117         // (ie., they have no remaining lost data). Otherwise, increasing
 118         // the backlog could take clients into a newly valid area of the backlog,
 119         // sending a stream of zeros instead of skipping the data as it should.
 120         //
 121         // TODO: Do this when clients are added back from serialized state instead;
 122         // it would probably be less wasteful.
 123         for (map<int, Client>::iterator client_it = clients.begin();
 124              client_it != clients.end();
 125              ++client_it) {
 126                 skip_lost_data(&client_it->second);
 127         }
 128
 129         CubemapStateProto serialized;
 130         for (map<int, Client>::const_iterator client_it = clients.begin();
 131              client_it != clients.end();
 132              ++client_it) {
 133                 serialized.add_clients()->MergeFrom(client_it->second.serialize());
 134         }
 135         for (size_t i = 0; i < streams.size(); ++i) {
 136                 serialized.add_streams()->MergeFrom(streams[i]->serialize());
 137         }
 138         return serialized;
 139 }
 140
 141 void Server::add_client_deferred(int sock)
 142 {
 143         MutexLock lock(&queued_data_mutex);
 144         queued_add_clients.push_back(sock);
 145 }
 146
 147 void Server::add_client(int sock)
 148 {
 149         pair<map<int, Client>::iterator, bool> ret =
 150                 clients.insert(make_pair(sock, Client(sock)));
 151         assert(ret.second == true);  // Should not already exist.
 152         Client *client_ptr = &ret.first->second;
 153
 154         // Start listening on data from this socket.
 155         epoll_event ev;
 156         ev.events = EPOLLIN | EPOLLET | EPOLLRDHUP;
 157         ev.data.u64 = reinterpret_cast<uint64_t>(client_ptr);
 158         if (epoll_ctl(epoll_fd, EPOLL_CTL_ADD, sock, &ev) == -1) {
 159                 log_perror("epoll_ctl(EPOLL_CTL_ADD)");
 160                 exit(1);
 161         }
 162
 163         process_client(client_ptr);
 164 }
 165
 166 void Server::add_client_from_serialized(const ClientProto &client)
 167 {
 168         MutexLock lock(&mutex);
 169         Stream *stream;
 170         int stream_index = lookup_stream_by_url(client.url());
 171         if (stream_index == -1) {
 172                 assert(client.state() != Client::SENDING_DATA);
 173                 stream = NULL;
 174         } else {
 175                 stream = streams[stream_index];
 176         }
 177         pair<map<int, Client>::iterator, bool> ret =
 178                 clients.insert(make_pair(client.sock(), Client(client, stream)));
 179         assert(ret.second == true);  // Should not already exist.
 180         Client *client_ptr = &ret.first->second;
 181
 182         // Start listening on data from this socket.
 183         epoll_event ev;
 184         if (client.state() == Client::READING_REQUEST) {
 185                 ev.events = EPOLLIN | EPOLLET | EPOLLRDHUP;
 186         } else {
 187                 // If we don't have more data for this client, we'll be putting it into
 188                 // the sleeping array again soon.
 189                 ev.events = EPOLLOUT | EPOLLET | EPOLLRDHUP;
 190         }
 191         ev.data.u64 = reinterpret_cast<uint64_t>(client_ptr);
 192         if (epoll_ctl(epoll_fd, EPOLL_CTL_ADD, client.sock(), &ev) == -1) {
 193                 log_perror("epoll_ctl(EPOLL_CTL_ADD)");
 194                 exit(1);
 195         }
 196
 197         if (client_ptr->state == Client::SENDING_DATA &&
 198             client_ptr->stream_pos == client_ptr->stream->bytes_received) {
 199                 client_ptr->stream->put_client_to_sleep(client_ptr);
 200         } else {
 201                 process_client(client_ptr);
 202         }
 203 }
 204
 205 int Server::lookup_stream_by_url(const std::string &url) const
 206 {
 207         map<string, int>::const_iterator url_it = url_map.find(url);
 208         if (url_it == url_map.end()) {
 209                 return -1;
 210         }
 211         return url_it->second;
 212 }
 213
 214 int Server::add_stream(const string &url, size_t backlog_size, Stream::Encoding encoding)
 215 {
 216         MutexLock lock(&mutex);
 217         url_map.insert(make_pair(url, streams.size()));
 218         streams.push_back(new Stream(url, backlog_size, encoding));
 219         return streams.size() - 1;
 220 }
 221
 222 int Server::add_stream_from_serialized(const StreamProto &stream, int data_fd)
 223 {
 224         MutexLock lock(&mutex);
 225         url_map.insert(make_pair(stream.url(), streams.size()));
 226         streams.push_back(new Stream(stream, data_fd));
 227         return streams.size() - 1;
 228 }
 229
 230 void Server::set_backlog_size(int stream_index, size_t new_size)
 231 {
 232         MutexLock lock(&mutex);
 233         assert(stream_index >= 0 && stream_index < ssize_t(streams.size()));
 234         streams[stream_index]->set_backlog_size(new_size);
 235 }
 236
 237 void Server::set_encoding(int stream_index, Stream::Encoding encoding)
 238 {
 239         MutexLock lock(&mutex);
 240         assert(stream_index >= 0 && stream_index < ssize_t(streams.size()));
 241         streams[stream_index]->encoding = encoding;
 242 }
 243
 244 void Server::set_header(int stream_index, const string &http_header, const string &stream_header)
 245 {
 246         MutexLock lock(&mutex);
 247         assert(stream_index >= 0 && stream_index < ssize_t(streams.size()));
 248         streams[stream_index]->http_header = http_header;
 249         streams[stream_index]->stream_header = stream_header;
 250
 251         // If there are clients we haven't sent anything to yet, we should give
 252         // them the header, so push back into the SENDING_HEADER state.
 253         for (map<int, Client>::iterator client_it = clients.begin();
 254              client_it != clients.end();
 255              ++client_it) {
 256                 Client *client = &client_it->second;
 257                 if (client->state == Client::SENDING_DATA &&
 258                     client->stream_pos == 0) {
 259                         construct_header(client);
 260                 }
 261         }
 262 }
 263
 264 void Server::set_mark_pool(int stream_index, MarkPool *mark_pool)
 265 {
 266         MutexLock lock(&mutex);
 267         assert(clients.empty());
 268         assert(stream_index >= 0 && stream_index < ssize_t(streams.size()));
 269         streams[stream_index]->mark_pool = mark_pool;
 270 }
 271
 272 void Server::add_data_deferred(int stream_index, const char *data, size_t bytes)
 273 {
 274         MutexLock lock(&queued_data_mutex);
 275         assert(stream_index >= 0 && stream_index < ssize_t(streams.size()));
 276         streams[stream_index]->add_data_deferred(data, bytes);
 277 }
 278
 279 // See the .h file for postconditions after this function.
 280 void Server::process_client(Client *client)
 281 {
 282         switch (client->state) {
 283         case Client::READING_REQUEST: {
 284 read_request_again:
 285                 // Try to read more of the request.
 286                 char buf[1024];
 287                 int ret;
 288                 do {
 289                         ret = read(client->sock, buf, sizeof(buf));
 290                 } while (ret == -1 && errno == EINTR);
 291
 292                 if (ret == -1 && errno == EAGAIN) {
 293                         // No more data right now. Nothing to do.
 294                         // This is postcondition #2.
 295                         return;
 296                 }
 297                 if (ret == -1) {
 298                         log_perror("read");
 299                         close_client(client);
 300                         return;
 301                 }
 302                 if (ret == 0) {
 303                         // OK, the socket is closed.
 304                         close_client(client);
 305                         return;
 306                 }
 307
 308                 RequestParseStatus status = wait_for_double_newline(&client->request, buf, ret);
 309
 310                 switch (status) {
 311                 case RP_OUT_OF_SPACE:
 312                         log(WARNING, "[%s] Client sent overlong request!", client->remote_addr.c_str());
 313                         close_client(client);
 314                         return;
 315                 case RP_NOT_FINISHED_YET:
 316                         // OK, we don't have the entire header yet. Fine; we'll get it later.
 317                         // See if there's more data for us.
 318                         goto read_request_again;
 319                 case RP_EXTRA_DATA:
 320                         log(WARNING, "[%s] Junk data after request!", client->remote_addr.c_str());
 321                         close_client(client);
 322                         return;
 323                 case RP_FINISHED:
 324                         break;
 325                 }
 326
 327                 assert(status == RP_FINISHED);
 328
 329                 int error_code = parse_request(client);
 330                 if (error_code == 200) {
 331                         construct_header(client);
 332                 } else {
 333                         construct_error(client, error_code);
 334                 }
 335
 336                 // We've changed states, so fall through.
 337                 assert(client->state == Client::SENDING_ERROR ||
 338                        client->state == Client::SENDING_HEADER);
 339         }
 340         case Client::SENDING_ERROR:
 341         case Client::SENDING_HEADER: {
 342 sending_header_or_error_again:
 343                 int ret;
 344                 do {
 345                         ret = write(client->sock,
 346                                     client->header_or_error.data() + client->header_or_error_bytes_sent,
 347                                     client->header_or_error.size() - client->header_or_error_bytes_sent);
 348                 } while (ret == -1 && errno == EINTR);
 349
 350                 if (ret == -1 && errno == EAGAIN) {
 351                         // We're out of socket space, so now we're at the “low edge” of epoll's
 352                         // edge triggering. epoll will tell us when there is more room, so for now,
 353                         // just return.
 354                         // This is postcondition #4.
 355                         return;
 356                 }
 357
 358                 if (ret == -1) {
 359                         // Error! Postcondition #1.
 360                         log_perror("write");
 361                         close_client(client);
 362                         return;
 363                 }
 364
 365                 client->header_or_error_bytes_sent += ret;
 366                 assert(client->header_or_error_bytes_sent <= client->header_or_error.size());
 367
 368                 if (client->header_or_error_bytes_sent < client->header_or_error.size()) {
 369                         // We haven't sent all yet. Fine; go another round.
 370                         goto sending_header_or_error_again;
 371                 }
 372
 373                 // We're done sending the header or error! Clear it to release some memory.
 374                 client->header_or_error.clear();
 375
 376                 if (client->state == Client::SENDING_ERROR) {
 377                         // We're done sending the error, so now close.
 378                         // This is postcondition #1.
 379                         close_client(client);
 380                         return;
 381                 }
 382
 383                 // Start sending from the end. In other words, we won't send any of the backlog,
 384                 // but we'll start sending immediately as we get data.
 385                 // This is postcondition #3.
 386                 client->state = Client::SENDING_DATA;
 387                 if (client->stream_pos == size_t(-2)) {
 388                         client->stream_pos = std::min<size_t>(
 389                             client->stream->bytes_received - client->stream->backlog_size,
 390                             0);
 391                 } else {
 392                         // client->stream_pos should be -1, but it might not be,
 393                         // if we have clients from an older version.
 394                         client->stream_pos = client->stream->bytes_received;
 395                 }
 396                 client->stream->put_client_to_sleep(client);
 397                 return;
 398         }
 399         case Client::SENDING_DATA: {
 400                 skip_lost_data(client);
 401                 Stream *stream = client->stream;
 402
 403 sending_data_again:
 404                 size_t bytes_to_send = stream->bytes_received - client->stream_pos;
 405                 assert(bytes_to_send <= stream->backlog_size);
 406                 if (bytes_to_send == 0) {
 407                         return;
 408                 }
 409
 410                 // See if we need to split across the circular buffer.
 411                 bool more_data = false;
 412                 if ((client->stream_pos % stream->backlog_size) + bytes_to_send > stream->backlog_size) {
 413                         bytes_to_send = stream->backlog_size - (client->stream_pos % stream->backlog_size);
 414                         more_data = true;
 415                 }
 416
 417                 ssize_t ret;
 418                 do {
 419                         loff_t offset = client->stream_pos % stream->backlog_size;
 420                         ret = sendfile(client->sock, stream->data_fd, &offset, bytes_to_send);
 421                 } while (ret == -1 && errno == EINTR);
 422
 423                 if (ret == -1 && errno == EAGAIN) {
 424                         // We're out of socket space, so return; epoll will wake us up
 425                         // when there is more room.
 426                         // This is postcondition #4.
 427                         return;
 428                 }
 429                 if (ret == -1) {
 430                         // Error, close; postcondition #1.
 431                         log_perror("sendfile");
 432                         close_client(client);
 433                         return;
 434                 }
 435                 client->stream_pos += ret;
 436                 client->bytes_sent += ret;
 437
 438                 if (client->stream_pos == stream->bytes_received) {
 439                         // We don't have any more data for this client, so put it to sleep.
 440                         // This is postcondition #3.
 441                         stream->put_client_to_sleep(client);
 442                 } else if (more_data && size_t(ret) == bytes_to_send) {
 443                         goto sending_data_again;
 444                 }
 445                 break;
 446         }
 447         default:
 448                 assert(false);
 449         }
 450 }
 451
 452 // See if there's some data we've lost. Ideally, we should drop to a block boundary,
 453 // but resync will be the mux's problem.
 454 void Server::skip_lost_data(Client *client)
 455 {
 456         Stream *stream = client->stream;
 457         size_t bytes_to_send = stream->bytes_received - client->stream_pos;
 458         if (bytes_to_send > stream->backlog_size) {
 459                 size_t bytes_lost = bytes_to_send - stream->backlog_size;
 460                 client->stream_pos = stream->bytes_received - stream->backlog_size;
 461                 client->bytes_lost += bytes_lost;
 462                 ++client->num_loss_events;
 463
 464                 double loss_fraction = double(client->bytes_lost) / double(client->bytes_lost + client->bytes_sent);
 465                 log(WARNING, "[%s] Client lost %lld bytes (total loss: %.2f%%), maybe too slow connection",
 466                         client->remote_addr.c_str(),
 467                         (long long int)(bytes_lost),
 468                         100.0 * loss_fraction);
 469         }
 470 }
 471
 472 int Server::parse_request(Client *client)
 473 {
 474         vector<string> lines = split_lines(client->request);
 475         if (lines.empty()) {
 476                 return 400;  // Bad request (empty).
 477         }
 478
 479         vector<string> request_tokens = split_tokens(lines[0]);
 480         if (request_tokens.size() < 2) {
 481                 return 400;  // Bad request (empty).
 482         }
 483         if (request_tokens[0] != "GET") {
 484                 return 400;  // Should maybe be 405 instead?
 485         }
 486
 487         string url = request_tokens[1];
 488         if (url.find("?backlog") == url.size() - 8) {
 489                 client->stream_pos = -2;
 490                 url = url.substr(0, url.size() - 8);
 491         } else {
 492                 client->stream_pos = -1;
 493         }
 494
 495         map<string, int>::const_iterator url_map_it = url_map.find(url);
 496         if (url_map_it == url_map.end()) {
 497                 return 404;  // Not found.
 498         }
 499
 500         client->url = request_tokens[1];
 501         client->stream = streams[url_map_it->second];
 502         if (client->stream->mark_pool != NULL) {
 503                 client->fwmark = client->stream->mark_pool->get_mark();
 504         } else {
 505                 client->fwmark = 0;  // No mark.
 506         }
 507         if (setsockopt(client->sock, SOL_SOCKET, SO_MARK, &client->fwmark, sizeof(client->fwmark)) == -1) {
 508                 if (client->fwmark != 0) {
 509                         log_perror("setsockopt(SO_MARK)");
 510                 }
 511         }
 512         client->request.clear();
 513
 514         return 200;  // OK!
 515 }
 516
 517 void Server::construct_header(Client *client)
 518 {
 519         Stream *stream = client->stream;
 520         if (stream->encoding == Stream::STREAM_ENCODING_RAW) {
 521                 client->header_or_error = stream->http_header +
 522                         "\r\n" +
 523                         stream->stream_header;
 524         } else if (stream->encoding == Stream::STREAM_ENCODING_METACUBE) {
 525                 client->header_or_error = stream->http_header +
 526                         "Content-encoding: metacube\r\n" +
 527                         "\r\n";
 528                 if (!stream->stream_header.empty()) {
 529                         metacube_block_header hdr;
 530                         memcpy(hdr.sync, METACUBE_SYNC, sizeof(hdr.sync));
 531                         hdr.size = htonl(stream->stream_header.size());
 532                         hdr.flags = htonl(METACUBE_FLAGS_HEADER);
 533                         client->header_or_error.append(
 534                                 string(reinterpret_cast<char *>(&hdr), sizeof(hdr)));
 535                 }
 536                 client->header_or_error.append(stream->stream_header);
 537         } else {
 538                 assert(false);
 539         }
 540
 541         // Switch states.
 542         client->state = Client::SENDING_HEADER;
 543
 544         epoll_event ev;
 545         ev.events = EPOLLOUT | EPOLLET | EPOLLRDHUP;
 546         ev.data.u64 = reinterpret_cast<uint64_t>(client);
 547
 548         if (epoll_ctl(epoll_fd, EPOLL_CTL_MOD, client->sock, &ev) == -1) {
 549                 log_perror("epoll_ctl(EPOLL_CTL_MOD)");
 550                 exit(1);
 551         }
 552 }
 553
 554 void Server::construct_error(Client *client, int error_code)
 555 {
 556         char error[256];
 557         snprintf(error, 256, "HTTP/1.0 %d Error\r\nContent-type: text/plain\r\n\r\nSomething went wrong. Sorry.\r\n",
 558                 error_code);
 559         client->header_or_error = error;
 560
 561         // Switch states.
 562         client->state = Client::SENDING_ERROR;
 563
 564         epoll_event ev;
 565         ev.events = EPOLLOUT | EPOLLET | EPOLLRDHUP;
 566         ev.data.u64 = reinterpret_cast<uint64_t>(client);
 567
 568         if (epoll_ctl(epoll_fd, EPOLL_CTL_MOD, client->sock, &ev) == -1) {
 569                 log_perror("epoll_ctl(EPOLL_CTL_MOD)");
 570                 exit(1);
 571         }
 572 }
 573
 574 template<class T>
 575 void delete_from(vector<T> *v, T elem)
 576 {
 577         typename vector<T>::iterator new_end = remove(v->begin(), v->end(), elem);
 578         v->erase(new_end, v->end());
 579 }
 580
 581 void Server::close_client(Client *client)
 582 {
 583         if (epoll_ctl(epoll_fd, EPOLL_CTL_DEL, client->sock, NULL) == -1) {
 584                 log_perror("epoll_ctl(EPOLL_CTL_DEL)");
 585                 exit(1);
 586         }
 587
 588         // This client could be sleeping, so we'll need to fix that. (Argh, O(n).)
 589         if (client->stream != NULL) {
 590                 delete_from(&client->stream->sleeping_clients, client);
 591                 delete_from(&client->stream->to_process, client);
 592                 if (client->stream->mark_pool != NULL) {
 593                         int fwmark = client->fwmark;
 594                         client->stream->mark_pool->release_mark(fwmark);
 595                 }
 596         }
 597
 598         // Log to access_log.
 599         access_log->write(client->get_stats());
 600
 601         // Bye-bye!
 602         safe_close(client->sock);
 603
 604         clients.erase(client->sock);
 605 }
 606
 607 void Server::process_queued_data()
 608 {
 609         MutexLock lock(&queued_data_mutex);
 610
 611         for (size_t i = 0; i < queued_add_clients.size(); ++i) {
 612                 add_client(queued_add_clients[i]);
 613         }
 614         queued_add_clients.clear();
 615
 616         for (size_t i = 0; i < streams.size(); ++i) {
 617                 streams[i]->process_queued_data();
 618         }
 619 }