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

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