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

   1 #include <assert.h>
   2 #include <errno.h>
   3 #include <inttypes.h>
   4 #include <netinet/in.h>
   5 #include <netinet/tcp.h>
   6 #include <pthread.h>
   7 #include <stdint.h>
   8 #include <stdio.h>
   9 #include <stdlib.h>
  10 #include <string.h>
  11 #include <sys/epoll.h>
  12 #include <sys/sendfile.h>
  13 #include <sys/socket.h>
  14 #include <sys/types.h>
  15 #include <unistd.h>
  16 #include <algorithm>
  17 #include <map>
  18 #include <string>
  19 #include <utility>
  20 #include <vector>
  21
  22 #include "tlse.h"
  23
  24 #include "acceptor.h"
  25 #include "accesslog.h"
  26 #include "log.h"
  27 #include "metacube2.h"
  28 #include "parse.h"
  29 #include "server.h"
  30 #include "state.pb.h"
  31 #include "stream.h"
  32 #include "util.h"
  33
  34 #ifndef SO_MAX_PACING_RATE
  35 #define SO_MAX_PACING_RATE 47
  36 #endif
  37
  38 using namespace std;
  39
  40 extern AccessLogThread *access_log;
  41
  42 namespace {
  43
  44 inline bool is_equal(timespec a, timespec b)
  45 {
  46         return a.tv_sec == b.tv_sec &&
  47                a.tv_nsec == b.tv_nsec;
  48 }
  49
  50 inline bool is_earlier(timespec a, timespec b)
  51 {
  52         if (a.tv_sec != b.tv_sec)
  53                 return a.tv_sec < b.tv_sec;
  54         return a.tv_nsec < b.tv_nsec;
  55 }
  56
  57 }  // namespace
  58
  59 Server::Server()
  60 {
  61         epoll_fd = epoll_create(1024);  // Size argument is ignored.
  62         if (epoll_fd == -1) {
  63                 log_perror("epoll_fd");
  64                 exit(1);
  65         }
  66 }
  67
  68 Server::~Server()
  69 {
  70         safe_close(epoll_fd);
  71 }
  72
  73 vector<ClientStats> Server::get_client_stats() const
  74 {
  75         vector<ClientStats> ret;
  76
  77         lock_guard<mutex> lock(mu);
  78         for (const auto &fd_and_client : clients) {
  79                 ret.push_back(fd_and_client.second.get_stats());
  80         }
  81         return ret;
  82 }
  83
  84 void Server::do_work()
  85 {
  86         while (!should_stop()) {
  87                 // Wait until there's activity on at least one of the fds,
  88                 // or 20 ms (about one frame at 50 fps) has elapsed.
  89                 //
  90                 // We could in theory wait forever and rely on wakeup()
  91                 // from add_client_deferred() and add_data_deferred(),
  92                 // but wakeup is a pretty expensive operation, and the
  93                 // two threads might end up fighting over a lock, so it's
  94                 // seemingly (much) more efficient to just have a timeout here.
  95                 int nfds = epoll_pwait(epoll_fd, events, EPOLL_MAX_EVENTS, EPOLL_TIMEOUT_MS, &sigset_without_usr1_block);
  96                 if (nfds == -1 && errno != EINTR) {
  97                         log_perror("epoll_wait");
  98                         exit(1);
  99                 }
 100
 101                 lock_guard<mutex> lock(mu);  // We release the mutex between iterations.
 102
 103                 process_queued_data();
 104
 105                 // Process each client where we have socket activity.
 106                 for (int i = 0; i < nfds; ++i) {
 107                         Client *client = reinterpret_cast<Client *>(events[i].data.ptr);
 108
 109                         if (events[i].events & (EPOLLERR | EPOLLRDHUP | EPOLLHUP)) {
 110                                 close_client(client);
 111                                 continue;
 112                         }
 113
 114                         process_client(client);
 115                 }
 116
 117                 // Process each client where its stream has new data,
 118                 // even if there was no socket activity.
 119                 for (unique_ptr<Stream> &stream : streams) {
 120                         vector<Client *> to_process;
 121                         swap(stream->to_process, to_process);
 122                         for (Client *client : to_process) {
 123                                 process_client(client);
 124                         }
 125                 }
 126
 127                 // Finally, go through each client to see if it's timed out
 128                 // in the READING_REQUEST state. (Seemingly there are clients
 129                 // that can hold sockets up for days at a time without sending
 130                 // anything at all.)
 131                 timespec timeout_time;
 132                 if (clock_gettime(CLOCK_MONOTONIC_COARSE, &timeout_time) == -1) {
 133                         log_perror("clock_gettime(CLOCK_MONOTONIC_COARSE)");
 134                         continue;
 135                 }
 136                 timeout_time.tv_sec -= REQUEST_READ_TIMEOUT_SEC;
 137                 while (!clients_ordered_by_connect_time.empty()) {
 138                         const pair<timespec, int> &connect_time_and_fd = clients_ordered_by_connect_time.front();
 139
 140                         // See if we have reached the end of clients to process.
 141                         if (is_earlier(timeout_time, connect_time_and_fd.first)) {
 142                                 break;
 143                         }
 144
 145                         // If this client doesn't exist anymore, just ignore it
 146                         // (it was deleted earlier).
 147                         auto client_it = clients.find(connect_time_and_fd.second);
 148                         if (client_it == clients.end()) {
 149                                 clients_ordered_by_connect_time.pop();
 150                                 continue;
 151                         }
 152                         Client *client = &client_it->second;
 153                         if (!is_equal(client->connect_time, connect_time_and_fd.first)) {
 154                                 // Another client has taken this fd in the meantime.
 155                                 clients_ordered_by_connect_time.pop();
 156                                 continue;
 157                         }
 158
 159                         if (client->state != Client::READING_REQUEST) {
 160                                 // Only READING_REQUEST can time out.
 161                                 clients_ordered_by_connect_time.pop();
 162                                 continue;
 163                         }
 164
 165                         // OK, it timed out.
 166                         close_client(client);
 167                         clients_ordered_by_connect_time.pop();
 168                 }
 169         }
 170 }
 171
 172 CubemapStateProto Server::serialize(unordered_map<const string *, size_t> *short_response_pool)
 173 {
 174         // We don't serialize anything queued, so empty the queues.
 175         process_queued_data();
 176
 177         // Set all clients in a consistent state before serializing
 178         // (ie., they have no remaining lost data). Otherwise, increasing
 179         // the backlog could take clients into a newly valid area of the backlog,
 180         // sending a stream of zeros instead of skipping the data as it should.
 181         //
 182         // TODO: Do this when clients are added back from serialized state instead;
 183         // it would probably be less wasteful.
 184         for (auto &fd_and_client : clients) {
 185                 skip_lost_data(&fd_and_client.second);
 186         }
 187
 188         CubemapStateProto serialized;
 189         for (const auto &fd_and_client : clients) {
 190                 serialized.add_clients()->MergeFrom(fd_and_client.second.serialize(short_response_pool));
 191         }
 192         for (unique_ptr<Stream> &stream : streams) {
 193                 serialized.add_streams()->MergeFrom(stream->serialize());
 194         }
 195         return serialized;
 196 }
 197
 198 void Server::add_client_deferred(int sock, Acceptor *acceptor)
 199 {
 200         lock_guard<mutex> lock(queued_clients_mutex);
 201         queued_add_clients.push_back(std::make_pair(sock, acceptor));
 202 }
 203
 204 void Server::add_client(int sock, Acceptor *acceptor)
 205 {
 206         const bool is_tls = acceptor->is_tls();
 207         auto inserted = clients.insert(make_pair(sock, Client(sock)));
 208         assert(inserted.second == true);  // Should not already exist.
 209         Client *client_ptr = &inserted.first->second;
 210
 211         // Connection timestamps must be nondecreasing. I can't find any guarantee
 212         // that even the monotonic clock can't go backwards by a small amount
 213         // (think switching between CPUs with non-synchronized TSCs), so if
 214         // this actually should happen, we hack around it by fudging
 215         // connect_time.
 216         if (!clients_ordered_by_connect_time.empty() &&
 217             is_earlier(client_ptr->connect_time, clients_ordered_by_connect_time.back().first)) {
 218                 client_ptr->connect_time = clients_ordered_by_connect_time.back().first;
 219         }
 220         clients_ordered_by_connect_time.push(make_pair(client_ptr->connect_time, sock));
 221
 222         // Start listening on data from this socket.
 223         epoll_event ev;
 224         if (is_tls) {
 225                 // Even in the initial state (READING_REQUEST), TLS needs to
 226                 // send data for the handshake, and thus might end up needing
 227                 // to know about EPOLLOUT.
 228                 ev.events = EPOLLIN | EPOLLOUT | EPOLLET | EPOLLRDHUP;
 229         } else {
 230                 // EPOLLOUT will be added once we go out of READING_REQUEST.
 231                 ev.events = EPOLLIN | EPOLLET | EPOLLRDHUP;
 232         }
 233         ev.data.ptr = client_ptr;
 234         if (epoll_ctl(epoll_fd, EPOLL_CTL_ADD, sock, &ev) == -1) {
 235                 log_perror("epoll_ctl(EPOLL_CTL_ADD)");
 236                 exit(1);
 237         }
 238
 239         if (is_tls) {
 240                 assert(tls_server_contexts.count(acceptor));
 241                 client_ptr->tls_context = tls_accept(tls_server_contexts[acceptor]);
 242                 if (client_ptr->tls_context == nullptr) {
 243                         log(ERROR, "tls_accept() failed");
 244                         close_client(client_ptr);
 245                         return;
 246                 }
 247                 tls_make_exportable(client_ptr->tls_context, 1);
 248         }
 249
 250         process_client(client_ptr);
 251 }
 252
 253 void Server::add_client_from_serialized(const ClientProto &client, const vector<shared_ptr<const string>> &short_responses)
 254 {
 255         lock_guard<mutex> lock(mu);
 256         Stream *stream;
 257         int stream_index = lookup_stream_by_url(client.url());
 258         if (stream_index == -1) {
 259                 assert(client.state() != Client::SENDING_DATA);
 260                 stream = nullptr;
 261         } else {
 262                 stream = streams[stream_index].get();
 263         }
 264         auto inserted = clients.insert(make_pair(client.sock(), Client(client, short_responses, stream)));
 265         assert(inserted.second == true);  // Should not already exist.
 266         Client *client_ptr = &inserted.first->second;
 267
 268         // Connection timestamps must be nondecreasing.
 269         assert(clients_ordered_by_connect_time.empty() ||
 270                !is_earlier(client_ptr->connect_time, clients_ordered_by_connect_time.back().first));
 271         clients_ordered_by_connect_time.push(make_pair(client_ptr->connect_time, client.sock()));
 272
 273         // Start listening on data from this socket.
 274         epoll_event ev;
 275         if (client.state() == Client::READING_REQUEST) {
 276                 // See the corresponding comment in Server::add_client().
 277                 if (client.has_tls_context()) {
 278                         ev.events = EPOLLIN | EPOLLOUT | EPOLLET | EPOLLRDHUP;
 279                 } else {
 280                         ev.events = EPOLLIN | EPOLLET | EPOLLRDHUP;
 281                 }
 282         } else {
 283                 // If we don't have more data for this client, we'll be putting it into
 284                 // the sleeping array again soon.
 285                 ev.events = EPOLLOUT | EPOLLET | EPOLLRDHUP;
 286         }
 287         ev.data.ptr = client_ptr;
 288         if (epoll_ctl(epoll_fd, EPOLL_CTL_ADD, client.sock(), &ev) == -1) {
 289                 log_perror("epoll_ctl(EPOLL_CTL_ADD)");
 290                 exit(1);
 291         }
 292
 293         if (client_ptr->state == Client::WAITING_FOR_KEYFRAME ||
 294             client_ptr->state == Client::PREBUFFERING ||
 295             (client_ptr->state == Client::SENDING_DATA &&
 296              client_ptr->stream_pos == client_ptr->stream->bytes_received)) {
 297                 client_ptr->stream->put_client_to_sleep(client_ptr);
 298         } else {
 299                 process_client(client_ptr);
 300         }
 301 }
 302
 303 int Server::lookup_stream_by_url(const string &url) const
 304 {
 305         const auto stream_url_it = stream_url_map.find(url);
 306         if (stream_url_it == stream_url_map.end()) {
 307                 return -1;
 308         }
 309         return stream_url_it->second;
 310 }
 311
 312 int Server::add_stream(const string &url,
 313                        const string &hls_url,
 314                        size_t backlog_size,
 315                        size_t prebuffering_bytes,
 316                        Stream::Encoding encoding,
 317                        Stream::Encoding src_encoding,
 318                        unsigned hls_frag_duration,
 319                        size_t hls_backlog_margin,
 320                        const string &allow_origin)
 321 {
 322         lock_guard<mutex> lock(mu);
 323         stream_url_map.insert(make_pair(url, streams.size()));
 324         if (!hls_url.empty()) {
 325                 stream_hls_url_map.insert(make_pair(hls_url, streams.size()));
 326         }
 327         streams.emplace_back(new Stream(url, backlog_size, prebuffering_bytes, encoding, src_encoding, hls_frag_duration, hls_backlog_margin, allow_origin));
 328         return streams.size() - 1;
 329 }
 330
 331 int Server::add_stream_from_serialized(const StreamProto &stream, int data_fd)
 332 {
 333         lock_guard<mutex> lock(mu);
 334         stream_url_map.insert(make_pair(stream.url(), streams.size()));
 335         // stream_hls_url_map will be updated in register_hls_url(), since it is not part
 336         // of the serialized state (it will always be picked out from the configuration).
 337         streams.emplace_back(new Stream(stream, data_fd));
 338         return streams.size() - 1;
 339 }
 340
 341 void Server::set_backlog_size(int stream_index, size_t new_size)
 342 {
 343         lock_guard<mutex> lock(mu);
 344         assert(stream_index >= 0 && stream_index < ssize_t(streams.size()));
 345         streams[stream_index]->set_backlog_size(new_size);
 346 }
 347
 348 void Server::set_prebuffering_bytes(int stream_index, size_t new_amount)
 349 {
 350         lock_guard<mutex> lock(mu);
 351         assert(stream_index >= 0 && stream_index < ssize_t(streams.size()));
 352         streams[stream_index]->prebuffering_bytes = new_amount;
 353 }
 354
 355 void Server::set_encoding(int stream_index, Stream::Encoding encoding)
 356 {
 357         lock_guard<mutex> lock(mu);
 358         assert(stream_index >= 0 && stream_index < ssize_t(streams.size()));
 359         streams[stream_index]->encoding = encoding;
 360 }
 361
 362 void Server::set_src_encoding(int stream_index, Stream::Encoding encoding)
 363 {
 364         lock_guard<mutex> lock(mu);
 365         assert(stream_index >= 0 && stream_index < ssize_t(streams.size()));
 366         streams[stream_index]->src_encoding = encoding;
 367 }
 368
 369 void Server::set_hls_frag_duration(int stream_index, unsigned hls_frag_duration)
 370 {
 371         lock_guard<mutex> lock(mu);
 372         assert(stream_index >= 0 && stream_index < ssize_t(streams.size()));
 373         streams[stream_index]->hls_frag_duration = hls_frag_duration;
 374 }
 375
 376 void Server::set_hls_backlog_margin(int stream_index, size_t hls_backlog_margin)
 377 {
 378         lock_guard<mutex> lock(mu);
 379         assert(stream_index >= 0 && stream_index < ssize_t(streams.size()));
 380         assert(hls_backlog_margin >= 0);
 381         assert(hls_backlog_margin < streams[stream_index]->backlog_size);
 382         streams[stream_index]->hls_backlog_margin = hls_backlog_margin;
 383 }
 384
 385 void Server::set_allow_origin(int stream_index, const string &allow_origin)
 386 {
 387         lock_guard<mutex> lock(mu);
 388         assert(stream_index >= 0 && stream_index < ssize_t(streams.size()));
 389         streams[stream_index]->allow_origin = allow_origin;
 390 }
 391
 392 void Server::register_hls_url(int stream_index, const string &hls_url)
 393 {
 394         lock_guard<mutex> lock(mu);
 395         assert(stream_index >= 0 && stream_index < ssize_t(streams.size()));
 396         assert(!hls_url.empty());
 397         stream_hls_url_map.insert(make_pair(hls_url, stream_index));
 398 }
 399
 400 void Server::set_header(int stream_index, const string &http_header, const string &stream_header)
 401 {
 402         lock_guard<mutex> lock(mu);
 403         assert(stream_index >= 0 && stream_index < ssize_t(streams.size()));
 404         Stream *stream = streams[stream_index].get();
 405         stream->http_header = http_header;
 406
 407         if (stream_header != stream->stream_header) {
 408                 // We cannot start at any of the older starting points anymore,
 409                 // since they'd get the wrong header for the stream (not to mention
 410                 // that a changed header probably means the stream restarted,
 411                 // which means any client starting on the old one would probably
 412                 // stop playing properly at the change point). Next block
 413                 // should be a suitable starting point (if not, something is
 414                 // pretty strange), so it will fill up again soon enough.
 415                 stream->suitable_starting_points.clear();
 416
 417                 if (!stream->fragments.empty()) {
 418                         stream->fragments.clear();
 419                         ++stream->discontinuity_counter;
 420                         stream->clear_hls_playlist_cache();
 421                 }
 422         }
 423         stream->stream_header = stream_header;
 424 }
 425
 426 void Server::set_pacing_rate(int stream_index, uint32_t pacing_rate)
 427 {
 428         lock_guard<mutex> lock(mu);
 429         assert(clients.empty());
 430         assert(stream_index >= 0 && stream_index < ssize_t(streams.size()));
 431         streams[stream_index]->pacing_rate = pacing_rate;
 432 }
 433
 434 void Server::add_gen204(const std::string &url, const std::string &allow_origin)
 435 {
 436         lock_guard<mutex> lock(mu);
 437         assert(clients.empty());
 438         ping_url_map[url] = allow_origin;
 439 }
 440
 441 void Server::create_tls_context_for_acceptor(const Acceptor *acceptor)
 442 {
 443         assert(acceptor->is_tls());
 444
 445         bool is_server = true;
 446         TLSContext *server_context = tls_create_context(is_server, TLS_V12);
 447
 448         const string &cert = acceptor->get_certificate_chain();
 449         int num_cert = tls_load_certificates(server_context, reinterpret_cast<const unsigned char *>(cert.data()), cert.size());
 450         assert(num_cert > 0);  // Should have been checked by config earlier.
 451
 452         const string &key = acceptor->get_private_key();
 453         int num_key = tls_load_private_key(server_context, reinterpret_cast<const unsigned char *>(key.data()), key.size());
 454         assert(num_key > 0);  // Should have been checked by config earlier.
 455
 456         tls_server_contexts.insert(make_pair(acceptor, server_context));
 457 }
 458
 459 void Server::add_data_deferred(int stream_index, const char *data, size_t bytes, uint16_t metacube_flags, const RationalPTS &pts)
 460 {
 461         assert(stream_index >= 0 && stream_index < ssize_t(streams.size()));
 462         streams[stream_index]->add_data_deferred(data, bytes, metacube_flags, pts);
 463 }
 464
 465 // See the .h file for postconditions after this function.
 466 void Server::process_client(Client *client)
 467 {
 468         switch (client->state) {
 469         case Client::READING_REQUEST: {
 470                 if (client->tls_context != nullptr) {
 471                         if (send_pending_tls_data(client)) {
 472                                 // send_pending_tls_data() hit postconditions #1 or #4.
 473                                 return;
 474                         }
 475                 }
 476
 477 read_request_again:
 478                 // Try to read more of the request.
 479                 char buf[1024];
 480                 int ret;
 481                 if (client->tls_context == nullptr) {
 482                         ret = read_nontls_data(client, buf, sizeof(buf));
 483                         if (ret == -1) {
 484                                 // read_nontls_data() hit postconditions #1 or #2.
 485                                 return;
 486                         }
 487                 } else {
 488                         ret = read_tls_data(client, buf, sizeof(buf));
 489                         if (ret == -1) {
 490                                 // read_tls_data() hit postconditions #1, #2 or #4.
 491                                 return;
 492                         }
 493                 }
 494
 495                 RequestParseStatus status = wait_for_double_newline(&client->request, buf, ret);
 496
 497                 switch (status) {
 498                 case RP_OUT_OF_SPACE:
 499                         log(WARNING, "[%s] Client sent overlong request!", client->remote_addr.c_str());
 500                         close_client(client);
 501                         return;
 502                 case RP_NOT_FINISHED_YET:
 503                         // OK, we don't have the entire header yet. Fine; we'll get it later.
 504                         // See if there's more data for us.
 505                         goto read_request_again;
 506                 case RP_EXTRA_DATA:
 507                         log(WARNING, "[%s] Junk data after request!", client->remote_addr.c_str());
 508                         close_client(client);
 509                         return;
 510                 case RP_FINISHED:
 511                         break;
 512                 }
 513
 514                 assert(status == RP_FINISHED);
 515
 516                 if (client->tls_context && !client->in_ktls_mode && tls_established(client->tls_context)) {
 517                         // We're ready to enter kTLS mode, unless we still have some
 518                         // handshake data to send (which then must be sent as non-kTLS).
 519                         if (send_pending_tls_data(client)) {
 520                                 // send_pending_tls_data() hit postconditions #1 or #4.
 521                                 return;
 522                         }
 523                         ret = tls_make_ktls(client->tls_context, client->sock);
 524                         if (ret < 0) {
 525                                 log_tls_error("tls_make_ktls", ret);
 526                                 close_client(client);
 527                                 return;
 528                         }
 529                         client->in_ktls_mode = true;
 530                 }
 531
 532                 int error_code = parse_request(client);
 533                 if (error_code == 200) {
 534                         if (client->serving_hls_playlist) {
 535                                 construct_hls_playlist(client);
 536                         } else {
 537                                 construct_stream_header(client);
 538                         }
 539                 } else if (error_code == 204) {
 540                         construct_204(client);
 541                 } else {
 542                         construct_error(client, error_code);
 543                 }
 544
 545                 // We've changed states, so fall through.
 546                 assert(client->state == Client::SENDING_SHORT_RESPONSE ||
 547                        client->state == Client::SENDING_HEADER);
 548         }
 549         case Client::SENDING_SHORT_RESPONSE:
 550         case Client::SENDING_HEADER: {
 551 sending_header_or_short_response_again:
 552                 int ret;
 553                 do {
 554                         ret = write(client->sock,
 555                                     client->header_or_short_response->data() + client->header_or_short_response_bytes_sent,
 556                                     client->header_or_short_response->size() - client->header_or_short_response_bytes_sent);
 557                 } while (ret == -1 && errno == EINTR);
 558
 559                 if (ret == -1 && errno == EAGAIN) {
 560                         // We're out of socket space, so now we're at the “low edge” of epoll's
 561                         // edge triggering. epoll will tell us when there is more room, so for now,
 562                         // just return.
 563                         // This is postcondition #4.
 564                         return;
 565                 }
 566
 567                 if (ret == -1) {
 568                         // Error! Postcondition #1.
 569                         log_perror("write");
 570                         close_client(client);
 571                         return;
 572                 }
 573
 574                 client->header_or_short_response_bytes_sent += ret;
 575                 assert(client->header_or_short_response_bytes_sent <= client->header_or_short_response->size());
 576
 577                 if (client->header_or_short_response_bytes_sent < client->header_or_short_response->size()) {
 578                         // We haven't sent all yet. Fine; go another round.
 579                         goto sending_header_or_short_response_again;
 580                 }
 581
 582                 // We're done sending the header or error! Clear it to release some memory.
 583                 client->header_or_short_response = nullptr;
 584                 client->header_or_short_response_holder.clear();
 585                 client->header_or_short_response_ref.reset();
 586
 587                 if (client->state == Client::SENDING_SHORT_RESPONSE) {
 588                         if (more_requests(client)) {
 589                                 // We're done sending the error, but should keep on reading new requests.
 590                                 goto read_request_again;
 591                         } else {
 592                                 // We're done sending the error, so now close.
 593                                 // This is postcondition #1.
 594                                 close_client(client);
 595                         }
 596                         return;
 597                 }
 598
 599                 Stream *stream = client->stream;
 600                 if (client->stream_pos == Client::STREAM_POS_AT_START) {
 601                         // Start sending from the beginning of the backlog.
 602                         client->stream_pos = min<size_t>(
 603                             stream->bytes_received - stream->backlog_size,
 604                             0);
 605                         client->state = Client::SENDING_DATA;
 606                         goto sending_data;
 607                 } else if (client->stream_pos_end != Client::STREAM_POS_NO_END) {
 608                         // We're sending a fragment, and should have all of it,
 609                         // so start sending right away.
 610                         assert(client->stream_pos >= 0);
 611                         client->state = Client::SENDING_DATA;
 612                         goto sending_data;
 613                 } else if (stream->prebuffering_bytes == 0) {
 614                         // Start sending from the first keyframe we get. In other
 615                         // words, we won't send any of the backlog, but we'll start
 616                         // sending immediately as we get the next keyframe block.
 617                         // Note that this is functionally identical to the next if branch,
 618                         // except that we save a binary search.
 619                         assert(client->stream_pos == Client::STREAM_POS_AT_END);
 620                         assert(client->stream_pos_end == Client::STREAM_POS_NO_END);
 621                         client->stream_pos = stream->bytes_received;
 622                         client->state = Client::WAITING_FOR_KEYFRAME;
 623                 } else {
 624                         // We're not going to send anything to the client before we have
 625                         // N bytes. However, this wait might be boring; we can just as well
 626                         // use it to send older data if we have it. We use lower_bound()
 627                         // so that we are conservative and never add extra latency over just
 628                         // waiting (assuming CBR or nearly so); otherwise, we could want e.g.
 629                         // 100 kB prebuffer but end up sending a 10 MB GOP.
 630                         assert(client->stream_pos == Client::STREAM_POS_AT_END);
 631                         assert(client->stream_pos_end == Client::STREAM_POS_NO_END);
 632                         deque<size_t>::const_iterator starting_point_it =
 633                                 lower_bound(stream->suitable_starting_points.begin(),
 634                                             stream->suitable_starting_points.end(),
 635                                             stream->bytes_received - stream->prebuffering_bytes);
 636                         if (starting_point_it == stream->suitable_starting_points.end()) {
 637                                 // None found. Just put us at the end, and then wait for the
 638                                 // first keyframe to appear.
 639                                 client->stream_pos = stream->bytes_received;
 640                                 client->state = Client::WAITING_FOR_KEYFRAME;
 641                         } else {
 642                                 client->stream_pos = *starting_point_it;
 643                                 client->state = Client::PREBUFFERING;
 644                                 goto prebuffering;
 645                         }
 646                 }
 647                 // Fall through.
 648         }
 649         case Client::WAITING_FOR_KEYFRAME: {
 650                 Stream *stream = client->stream;
 651                 if (stream->suitable_starting_points.empty() ||
 652                     client->stream_pos > stream->suitable_starting_points.back()) {
 653                         // We haven't received a keyframe since this stream started waiting,
 654                         // so keep on waiting for one.
 655                         // This is postcondition #3.
 656                         stream->put_client_to_sleep(client);
 657                         return;
 658                 }
 659                 client->stream_pos = stream->suitable_starting_points.back();
 660                 client->state = Client::PREBUFFERING;
 661                 // Fall through.
 662         }
 663         case Client::PREBUFFERING: {
 664 prebuffering:
 665                 Stream *stream = client->stream;
 666                 size_t bytes_to_send = stream->bytes_received - client->stream_pos;
 667                 assert(bytes_to_send <= stream->backlog_size);
 668                 if (bytes_to_send < stream->prebuffering_bytes) {
 669                         // We don't have enough bytes buffered to start this client yet.
 670                         // This is postcondition #3.
 671                         stream->put_client_to_sleep(client);
 672                         return;
 673                 }
 674                 client->state = Client::SENDING_DATA;
 675                 // Fall through.
 676         }
 677         case Client::SENDING_DATA: {
 678 sending_data:
 679                 skip_lost_data(client);
 680                 Stream *stream = client->stream;
 681
 682 sending_data_again:
 683                 size_t bytes_to_send;
 684                 if (client->stream_pos_end == Client::STREAM_POS_NO_END) {
 685                          bytes_to_send = stream->bytes_received - client->stream_pos;
 686                 } else {
 687                          bytes_to_send = client->stream_pos_end - client->stream_pos;
 688                 }
 689                 assert(bytes_to_send <= stream->backlog_size);
 690                 if (bytes_to_send == 0) {
 691                         if (client->stream_pos == client->stream_pos_end) {  // We have a definite end, and we're at it.
 692                                 if (more_requests(client)) {
 693                                         // We're done sending the fragment, but should keep on reading new requests.
 694                                         goto read_request_again;
 695                                 } else {
 696                                         // We're done sending the fragment, so now close.
 697                                         // This is postcondition #1.
 698                                         close_client(client);
 699                                 }
 700                         }
 701                         return;
 702                 }
 703
 704                 // See if we need to split across the circular buffer.
 705                 bool more_data = false;
 706                 if ((client->stream_pos % stream->backlog_size) + bytes_to_send > stream->backlog_size) {
 707                         bytes_to_send = stream->backlog_size - (client->stream_pos % stream->backlog_size);
 708                         more_data = true;
 709                 }
 710
 711                 ssize_t ret;
 712                 do {
 713                         off_t offset = client->stream_pos % stream->backlog_size;
 714                         ret = sendfile(client->sock, stream->data_fd, &offset, bytes_to_send);
 715                 } while (ret == -1 && errno == EINTR);
 716
 717                 if (ret == -1 && errno == EAGAIN) {
 718                         // We're out of socket space, so return; epoll will wake us up
 719                         // when there is more room.
 720                         // This is postcondition #4.
 721                         return;
 722                 }
 723                 if (ret == -1) {
 724                         // Error, close; postcondition #1.
 725                         log_perror("sendfile");
 726                         close_client(client);
 727                         return;
 728                 }
 729                 client->stream_pos += ret;
 730                 client->bytes_sent += ret;
 731
 732                 assert(client->stream_pos_end == Client::STREAM_POS_NO_END || client->stream_pos <= client->stream_pos_end);
 733                 if (client->stream_pos == client->stream_pos_end) {
 734                         goto sending_data_again;  // Will see that bytes_to_send == 0 and end.
 735                 } else if (client->stream_pos == stream->bytes_received) {
 736                         // We don't have any more data for this client, so put it to sleep.
 737                         // This is postcondition #3.
 738                         stream->put_client_to_sleep(client);
 739                 } else if (more_data && size_t(ret) == bytes_to_send) {
 740                         goto sending_data_again;
 741                 }
 742                 // We'll also get here for postcondition #4 (similar to the EAGAIN path above).
 743                 break;
 744         }
 745         default:
 746                 assert(false);
 747         }
 748 }
 749
 750 bool Server::send_pending_tls_data(Client *client)
 751 {
 752         // See if there's data from the TLS library to write.
 753         if (client->tls_data_to_send == nullptr) {
 754                 client->tls_data_to_send = tls_get_write_buffer(client->tls_context, &client->tls_data_left_to_send);
 755                 if (client->tls_data_to_send == nullptr) {
 756                         // Really no data to send.
 757                         return false;
 758                 }
 759         }
 760
 761 send_data_again:
 762         int ret;
 763         do {
 764                 ret = write(client->sock, client->tls_data_to_send, client->tls_data_left_to_send);
 765         } while (ret == -1 && errno == EINTR);
 766         assert(ret < 0 || size_t(ret) <= client->tls_data_left_to_send);
 767
 768         if (ret == -1 && errno == EAGAIN) {
 769                 // We're out of socket space, so now we're at the “low edge” of epoll's
 770                 // edge triggering. epoll will tell us when there is more room, so for now,
 771                 // just return.
 772                 // This is postcondition #4.
 773                 return true;
 774         }
 775         if (ret == -1) {
 776                 // Error! Postcondition #1.
 777                 log_perror("write");
 778                 close_client(client);
 779                 return true;
 780         }
 781         if (ret > 0 && size_t(ret) == client->tls_data_left_to_send) {
 782                 // All data has been sent, so we don't need to go to sleep.
 783                 tls_buffer_clear(client->tls_context);
 784                 client->tls_data_to_send = nullptr;
 785                 return false;
 786         }
 787
 788         // More data to send, so try again.
 789         client->tls_data_to_send += ret;
 790         client->tls_data_left_to_send -= ret;
 791         goto send_data_again;
 792 }
 793
 794 int Server::read_nontls_data(Client *client, char *buf, size_t max_size)
 795 {
 796         int ret;
 797         do {
 798                 ret = read(client->sock, buf, max_size);
 799         } while (ret == -1 && errno == EINTR);
 800
 801         if (ret == -1 && errno == EAGAIN) {
 802                 // No more data right now. Nothing to do.
 803                 // This is postcondition #2.
 804                 return -1;
 805         }
 806         if (ret == -1) {
 807                 log_perror("read");
 808                 close_client(client);
 809                 return -1;
 810         }
 811         if (ret == 0) {
 812                 // OK, the socket is closed.
 813                 close_client(client);
 814                 return -1;
 815         }
 816
 817         return ret;
 818 }
 819
 820 int Server::read_tls_data(Client *client, char *buf, size_t max_size)
 821 {
 822 read_again:
 823         int ret;
 824         do {
 825                 ret = read(client->sock, buf, max_size);
 826         } while (ret == -1 && errno == EINTR);
 827
 828         if (ret == -1 && errno == EAGAIN) {
 829                 // No more data right now. Nothing to do.
 830                 // This is postcondition #2.
 831                 return -1;
 832         }
 833         if (ret == -1) {
 834                 log_perror("read");
 835                 close_client(client);
 836                 return -1;
 837         }
 838         if (ret == 0) {
 839                 // OK, the socket is closed.
 840                 close_client(client);
 841                 return -1;
 842         }
 843
 844         // Give it to the TLS library.
 845         int err = tls_consume_stream(client->tls_context, reinterpret_cast<const unsigned char *>(buf), ret, nullptr);
 846         if (err < 0) {
 847                 log_tls_error("tls_consume_stream", err);
 848                 close_client(client);
 849                 return -1;
 850         }
 851         if (err == 0) {
 852                 // Not consumed any data. See if we can read more.
 853                 goto read_again;
 854         }
 855
 856         // Read any decrypted data available for us. (We can reuse buf, since it's free now.)
 857         ret = tls_read(client->tls_context, reinterpret_cast<unsigned char *>(buf), max_size);
 858         if (ret == 0) {
 859                 // No decrypted data for us yet, but there might be some more handshaking
 860                 // to send. Do that if needed, then look for more data.
 861                 if (send_pending_tls_data(client)) {
 862                         // send_pending_tls_data() hit postconditions #1 or #4.
 863                         return -1;
 864                 }
 865                 goto read_again;
 866         }
 867         if (ret < 0) {
 868                 log_tls_error("tls_read", ret);
 869                 close_client(client);
 870                 return -1;
 871         }
 872
 873         assert(ret > 0);
 874         return ret;
 875 }
 876
 877 // See if there's some data we've lost. Ideally, we should drop to a block boundary,
 878 // but resync will be the mux's problem.
 879 void Server::skip_lost_data(Client *client)
 880 {
 881         Stream *stream = client->stream;
 882         if (stream == nullptr) {
 883                 return;
 884         }
 885         size_t bytes_to_send = stream->bytes_received - client->stream_pos;
 886         if (bytes_to_send > stream->backlog_size) {
 887                 size_t bytes_lost = bytes_to_send - stream->backlog_size;
 888                 client->bytes_lost += bytes_lost;
 889                 ++client->num_loss_events;
 890                 if (!client->close_after_response) {
 891                         assert(client->stream_pos_end != Client::STREAM_POS_NO_END);
 892
 893                         // We've already sent a Content-length, so we can't just skip data.
 894                         // Close the connection immediately and hope the other side
 895                         // is able to figure out that there was an error and it needs to skip.
 896                         client->close_after_response = true;
 897                         client->stream_pos = client->stream_pos_end;
 898                 } else {
 899                         client->stream_pos = stream->bytes_received - stream->backlog_size;
 900                 }
 901         }
 902 }
 903
 904 int Server::parse_request(Client *client)
 905 {
 906         vector<string> lines = split_lines(client->request);
 907         client->request.clear();
 908         if (lines.empty()) {
 909                 return 400;  // Bad request (empty).
 910         }
 911
 912         // Parse the headers, for logging purposes.
 913         // TODO: Case-insensitivity.
 914         unordered_multimap<string, string> headers = extract_headers(lines, client->remote_addr);
 915         const auto referer_it = headers.find("Referer");
 916         if (referer_it != headers.end()) {
 917                 client->referer = referer_it->second;
 918         }
 919         const auto user_agent_it = headers.find("User-Agent");
 920         if (user_agent_it != headers.end()) {
 921                 client->user_agent = user_agent_it->second;
 922         }
 923
 924         vector<string> request_tokens = split_tokens(lines[0]);
 925         if (request_tokens.size() < 3) {
 926                 return 400;  // Bad request (empty).
 927         }
 928         if (request_tokens[0] != "GET") {
 929                 return 400;  // Should maybe be 405 instead?
 930         }
 931
 932         string url = request_tokens[1];
 933         client->url = url;
 934         if (url.size() > 8 && url.find("?backlog") == url.size() - 8) {
 935                 client->stream_pos = Client::STREAM_POS_AT_START;
 936                 url = url.substr(0, url.size() - 8);
 937         } else {
 938                 size_t pos = url.find("?frag=");
 939                 if (pos != string::npos) {
 940                         // Parse an endpoint of the type /stream.mp4?frag=1234-5678.
 941                         const char *ptr = url.c_str() + pos + 6;
 942
 943                         // "?frag=header" is special.
 944                         if (strcmp(ptr, "header") == 0) {
 945                                 client->stream_pos = Client::STREAM_POS_HEADER_ONLY;
 946                                 client->stream_pos_end = -1;
 947                         } else {
 948                                 char *endptr;
 949                                 long long frag_start = strtol(ptr, &endptr, 10);
 950                                 if (ptr == endptr || frag_start < 0 || frag_start == LLONG_MAX) {
 951                                         return 400;  // Bad request.
 952                                 }
 953                                 if (*endptr != '-') {
 954                                         return 400;  // Bad request.
 955                                 }
 956                                 ptr = endptr + 1;
 957
 958                                 long long frag_end = strtol(ptr, &endptr, 10);
 959                                 if (ptr == endptr || frag_end < frag_start || frag_end == LLONG_MAX) {
 960                                         return 400;  // Bad request.
 961                                 }
 962
 963                                 if (*endptr != '\0') {
 964                                         return 400;  // Bad request.
 965                                 }
 966
 967                                 client->stream_pos = frag_start;
 968                                 client->stream_pos_end = frag_end;
 969                         }
 970                         url = url.substr(0, pos);
 971                 } else {
 972                         client->stream_pos = -1;
 973                         client->stream_pos_end = -1;
 974                 }
 975         }
 976
 977         // Figure out if we're supposed to close the socket after we've delivered the response.
 978         string protocol = request_tokens[2];
 979         if (protocol.find("HTTP/") != 0) {
 980                 return 400;  // Bad request.
 981         }
 982         client->close_after_response = false;
 983         client->http_11 = true;
 984         if (protocol == "HTTP/1.0") {
 985                 // No persistent connections.
 986                 client->close_after_response = true;
 987                 client->http_11 = false;
 988         } else {
 989                 const auto connection_it = headers.find("Connection");
 990                 if (connection_it != headers.end() && connection_it->second == "close") {
 991                         client->close_after_response = true;
 992                 }
 993         }
 994
 995         const auto stream_url_map_it = stream_url_map.find(url);
 996         if (stream_url_map_it != stream_url_map.end()) {
 997                 // Serve a regular stream..
 998                 client->stream = streams[stream_url_map_it->second].get();
 999                 client->serving_hls_playlist = false;
1000         } else {
1001                 const auto stream_hls_url_map_it = stream_hls_url_map.find(url);
1002                 if (stream_hls_url_map_it != stream_hls_url_map.end()) {
1003                         // Serve HLS playlist.
1004                         client->stream = streams[stream_hls_url_map_it->second].get();
1005                         client->serving_hls_playlist = true;
1006                 } else {
1007                         const auto ping_url_map_it = ping_url_map.find(url);
1008                         if (ping_url_map_it == ping_url_map.end()) {
1009                                 return 404;  // Not found.
1010                         } else {
1011                                 // Serve a ping (204 no error).
1012                                 return 204;
1013                         }
1014                 }
1015         }
1016
1017         Stream *stream = client->stream;
1018         if (stream->http_header.empty()) {
1019                 return 503;  // Service unavailable.
1020         }
1021
1022         if (client->serving_hls_playlist) {
1023                 if (stream->encoding == Stream::STREAM_ENCODING_METACUBE) {
1024                         // This doesn't make any sense, and is hard to implement, too.
1025                         return 404;
1026                 } else {
1027                         return 200;
1028                 }
1029         }
1030
1031         if (client->stream_pos_end == Client::STREAM_POS_NO_END) {
1032                 // This stream won't end, so we don't have a content-length,
1033                 // and can just as well tell the client it's Connection: close
1034                 // (otherwise, we'd have to implement chunking TE for no good reason).
1035                 client->close_after_response = true;
1036         } else {
1037                 if (stream->encoding == Stream::STREAM_ENCODING_METACUBE) {
1038                         // This doesn't make any sense, and is hard to implement, too.
1039                         return 416;  // Range not satisfiable.
1040                 }
1041
1042                 // Check that we have the requested fragment in our backlog.
1043                 size_t buffer_end = stream->bytes_received;
1044                 size_t buffer_start = (buffer_end <= stream->backlog_size) ? 0 : buffer_end - stream->backlog_size;
1045
1046                 if (client->stream_pos_end > buffer_end ||
1047                     client->stream_pos < buffer_start) {
1048                         return 416;  // Range not satisfiable.
1049                 }
1050         }
1051
1052         client->stream = stream;
1053         if (setsockopt(client->sock, SOL_SOCKET, SO_MAX_PACING_RATE, &client->stream->pacing_rate, sizeof(client->stream->pacing_rate)) == -1) {
1054                 if (client->stream->pacing_rate != ~0U) {
1055                         log_perror("setsockopt(SO_MAX_PACING_RATE)");
1056                 }
1057         }
1058         client->request.clear();
1059
1060         return 200;  // OK!
1061 }
1062
1063 void Server::construct_stream_header(Client *client)
1064 {
1065         Stream *stream = client->stream;
1066         string response = stream->http_header;
1067         if (client->stream_pos == Client::STREAM_POS_HEADER_ONLY) {
1068                 char buf[64];
1069                 snprintf(buf, sizeof(buf), "Content-length: %zu\r\n", stream->stream_header.size());
1070                 response.append(buf);
1071         } else if (client->stream_pos_end != Client::STREAM_POS_NO_END) {
1072                 char buf[64];
1073                 snprintf(buf, sizeof(buf), "Content-length: %" PRIu64 "\r\n", client->stream_pos_end - client->stream_pos);
1074                 response.append(buf);
1075         }
1076         if (client->http_11) {
1077                 assert(response.find("HTTP/1.0") == 0);
1078                 response[7] = '1';  // Change to HTTP/1.1.
1079                 if (client->close_after_response) {
1080                         response.append("Connection: close\r\n");
1081                 }
1082         } else {
1083                 assert(client->close_after_response);
1084         }
1085         if (!stream->allow_origin.empty()) {
1086                 response.append("Access-Control-Allow-Origin: ");
1087                 response.append(stream->allow_origin);
1088                 response.append("\r\n");
1089         }
1090         if (stream->encoding == Stream::STREAM_ENCODING_RAW) {
1091                 response.append("\r\n");
1092         } else if (stream->encoding == Stream::STREAM_ENCODING_METACUBE) {
1093                 response.append("Content-encoding: metacube\r\n\r\n");
1094                 if (!stream->stream_header.empty()) {
1095                         metacube2_block_header hdr;
1096                         memcpy(hdr.sync, METACUBE2_SYNC, sizeof(hdr.sync));
1097                         hdr.size = htonl(stream->stream_header.size());
1098                         hdr.flags = htons(METACUBE_FLAGS_HEADER);
1099                         hdr.csum = htons(metacube2_compute_crc(&hdr));
1100                         response.append(string(reinterpret_cast<char *>(&hdr), sizeof(hdr)));
1101                 }
1102         } else {
1103                 assert(false);
1104         }
1105         if (client->stream_pos == Client::STREAM_POS_HEADER_ONLY) {
1106                 client->state = Client::SENDING_SHORT_RESPONSE;
1107                 response.append(stream->stream_header);
1108         } else {
1109                 client->state = Client::SENDING_HEADER;
1110                 if (client->stream_pos_end == Client::STREAM_POS_NO_END) {  // Fragments don't contain stream headers.
1111                         response.append(stream->stream_header);
1112                 }
1113         }
1114
1115         client->header_or_short_response_holder = move(response);
1116         client->header_or_short_response = &client->header_or_short_response_holder;
1117
1118         // Switch states.
1119         change_epoll_events(client, EPOLLOUT | EPOLLET | EPOLLRDHUP);
1120 }
1121
1122 void Server::construct_error(Client *client, int error_code)
1123 {
1124         char error[256];
1125         if (client->http_11 && client->close_after_response) {
1126                 snprintf(error, sizeof(error),
1127                         "HTTP/1.1 %d Error\r\nContent-type: text/plain\r\nConnection: close\r\n\r\nSomething went wrong. Sorry.\r\n",
1128                         error_code);
1129         } else {
1130                 snprintf(error, sizeof(error),
1131                         "HTTP/1.%d %d Error\r\nContent-type: text/plain\r\nContent-length: 30\r\n\r\nSomething went wrong. Sorry.\r\n",
1132                         client->http_11, error_code);
1133         }
1134         client->header_or_short_response_holder = error;
1135         client->header_or_short_response = &client->header_or_short_response_holder;
1136
1137         // Switch states.
1138         client->state = Client::SENDING_SHORT_RESPONSE;
1139         change_epoll_events(client, EPOLLOUT | EPOLLET | EPOLLRDHUP);
1140 }
1141
1142 void Server::construct_hls_playlist(Client *client)
1143 {
1144         Stream *stream = client->stream;
1145         shared_ptr<const string> *cache;
1146         if (client->http_11) {
1147                 if (client->close_after_response) {
1148                         cache = &stream->hls_playlist_http11_close;
1149                 } else {
1150                         cache = &stream->hls_playlist_http11_persistent;
1151                 }
1152         } else {
1153                 assert(client->close_after_response);
1154                 cache = &stream->hls_playlist_http10;
1155         }
1156
1157         if (*cache == nullptr) {
1158                 *cache = stream->generate_hls_playlist(client->http_11, client->close_after_response);
1159         }
1160         client->header_or_short_response_ref = *cache;
1161         client->header_or_short_response = cache->get();
1162
1163         // Switch states.
1164         client->state = Client::SENDING_SHORT_RESPONSE;
1165         change_epoll_events(client, EPOLLOUT | EPOLLET | EPOLLRDHUP);
1166 }
1167
1168 void Server::construct_204(Client *client)
1169 {
1170         const auto ping_url_map_it = ping_url_map.find(client->url);
1171         assert(ping_url_map_it != ping_url_map.end());
1172
1173         string response;
1174         if (client->http_11) {
1175                 response = "HTTP/1.1 204 No Content\r\n";
1176                 if (client->close_after_response) {
1177                         response.append("Connection: close\r\n");
1178                 }
1179         } else {
1180                 response = "HTTP/1.0 204 No Content\r\n";
1181                 assert(client->close_after_response);
1182         }
1183         if (!ping_url_map_it->second.empty()) {
1184                 response.append("Access-Control-Allow-Origin: ");
1185                 response.append(ping_url_map_it->second);
1186                 response.append("\r\n");
1187         }
1188         response.append("\r\n");
1189
1190         client->header_or_short_response_holder = move(response);
1191         client->header_or_short_response = &client->header_or_short_response_holder;
1192
1193         // Switch states.
1194         client->state = Client::SENDING_SHORT_RESPONSE;
1195         change_epoll_events(client, EPOLLOUT | EPOLLET | EPOLLRDHUP);
1196 }
1197
1198 template<class T>
1199 void delete_from(vector<T> *v, T elem)
1200 {
1201         typename vector<T>::iterator new_end = remove(v->begin(), v->end(), elem);
1202         v->erase(new_end, v->end());
1203 }
1204
1205 void Server::close_client(Client *client)
1206 {
1207         if (epoll_ctl(epoll_fd, EPOLL_CTL_DEL, client->sock, nullptr) == -1) {
1208                 log_perror("epoll_ctl(EPOLL_CTL_DEL)");
1209                 exit(1);
1210         }
1211
1212         // This client could be sleeping, so we'll need to fix that. (Argh, O(n).)
1213         if (client->stream != nullptr) {
1214                 delete_from(&client->stream->sleeping_clients, client);
1215                 delete_from(&client->stream->to_process, client);
1216         }
1217
1218         if (client->tls_context) {
1219                 tls_destroy_context(client->tls_context);
1220         }
1221
1222         // Log to access_log.
1223         access_log->write(client->get_stats());
1224
1225         // Bye-bye!
1226         safe_close(client->sock);
1227
1228         clients.erase(client->sock);
1229 }
1230
1231 void Server::change_epoll_events(Client *client, uint32_t events)
1232 {
1233         epoll_event ev;
1234         ev.events = events;
1235         ev.data.ptr = client;
1236
1237         if (epoll_ctl(epoll_fd, EPOLL_CTL_MOD, client->sock, &ev) == -1) {
1238                 log_perror("epoll_ctl(EPOLL_CTL_MOD)");
1239                 exit(1);
1240         }
1241 }
1242
1243 bool Server::more_requests(Client *client)
1244 {
1245         if (client->close_after_response) {
1246                 return false;
1247         }
1248
1249         // Log to access_log.
1250         access_log->write(client->get_stats());
1251
1252         // Flush pending data; does not cancel out TCP_CORK (since that still takes priority),
1253         // but does a one-off flush.
1254         int one = 1;
1255         if (setsockopt(client->sock, SOL_TCP, TCP_NODELAY, &one, sizeof(one)) == -1) {
1256                 log_perror("setsockopt(TCP_NODELAY)");
1257                 // Can still continue.
1258         }
1259
1260         // Switch states and reset the parsers. We don't reset statistics.
1261         client->state = Client::READING_REQUEST;
1262         client->url.clear();
1263         client->stream = NULL;
1264         client->header_or_short_response = nullptr;
1265         client->header_or_short_response_holder.clear();
1266         client->header_or_short_response_ref.reset();
1267         client->header_or_short_response_bytes_sent = 0;
1268
1269         change_epoll_events(client, EPOLLIN | EPOLLET | EPOLLRDHUP);  // No TLS handshake, so no EPOLLOUT needed.
1270
1271         return true;
1272 }
1273
1274 void Server::process_queued_data()
1275 {
1276         {
1277                 lock_guard<mutex> lock(queued_clients_mutex);
1278
1279                 for (const pair<int, Acceptor *> &id_and_acceptor : queued_add_clients) {
1280                         add_client(id_and_acceptor.first, id_and_acceptor.second);
1281                 }
1282                 queued_add_clients.clear();
1283         }
1284
1285         for (unique_ptr<Stream> &stream : streams) {
1286                 stream->process_queued_data();
1287         }
1288 }