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

   1 #include <assert.h>
   2 #include <errno.h>
   3 #include <inttypes.h>
   4 #include <limits.h>
   5 #include <netinet/in.h>
   6 #include <netinet/tcp.h>
   7 #include <pthread.h>
   8 #include <stdint.h>
   9 #include <stdio.h>
  10 #include <stdlib.h>
  11 #include <string.h>
  12 #include <sys/epoll.h>
  13 #include <sys/sendfile.h>
  14 #include <sys/socket.h>
  15 #include <sys/types.h>
  16 #include <unistd.h>
  17 #include <algorithm>
  18 #include <map>
  19 #include <string>
  20 #include <utility>
  21 #include <vector>
  22
  23 #include "ktls.h"
  24 #include "tlse.h"
  25
  26 #include "acceptor.h"
  27 #include "accesslog.h"
  28 #include "log.h"
  29 #include "metacube2.h"
  30 #include "parse.h"
  31 #include "server.h"
  32 #include "state.pb.h"
  33 #include "stream.h"
  34 #include "util.h"
  35
  36 #ifndef SO_MAX_PACING_RATE
  37 #define SO_MAX_PACING_RATE 47
  38 #endif
  39
  40 using namespace std;
  41
  42 extern AccessLogThread *access_log;
  43
  44 namespace {
  45
  46 inline bool is_equal(timespec a, timespec b)
  47 {
  48         return a.tv_sec == b.tv_sec &&
  49                a.tv_nsec == b.tv_nsec;
  50 }
  51
  52 inline bool is_earlier(timespec a, timespec b)
  53 {
  54         if (a.tv_sec != b.tv_sec)
  55                 return a.tv_sec < b.tv_sec;
  56         return a.tv_nsec < b.tv_nsec;
  57 }
  58
  59 }  // namespace
  60
  61 Server::Server()
  62 {
  63         epoll_fd = epoll_create(1024);  // Size argument is ignored.
  64         if (epoll_fd == -1) {
  65                 log_perror("epoll_fd");
  66                 exit(1);
  67         }
  68 }
  69
  70 Server::~Server()
  71 {
  72         safe_close(epoll_fd);
  73 }
  74
  75 vector<ClientStats> Server::get_client_stats() const
  76 {
  77         vector<ClientStats> ret;
  78
  79         lock_guard<mutex> lock(mu);
  80         for (const auto &fd_and_client : clients) {
  81                 ret.push_back(fd_and_client.second.get_stats());
  82         }
  83         return ret;
  84 }
  85
  86 vector<HLSZombie> Server::get_hls_zombies()
  87 {
  88         vector<HLSZombie> ret;
  89
  90         timespec now;
  91         if (clock_gettime(CLOCK_MONOTONIC_COARSE, &now) == -1) {
  92                 log_perror("clock_gettime(CLOCK_MONOTONIC_COARSE)");
  93                 return ret;
  94         }
  95
  96         lock_guard<mutex> lock(mu);
  97         for (auto it = hls_zombies.begin(); it != hls_zombies.end(); ) {
  98                 if (is_earlier(it->second.expires, now)) {
  99                         hls_zombies.erase(it++);
 100                 } else {
 101                         ret.push_back(it->second);
 102                         ++it;
 103                 }
 104         }
 105         return ret;
 106 }
 107
 108 void Server::do_work()
 109 {
 110         while (!should_stop()) {
 111                 // Wait until there's activity on at least one of the fds,
 112                 // or 20 ms (about one frame at 50 fps) has elapsed.
 113                 //
 114                 // We could in theory wait forever and rely on wakeup()
 115                 // from add_client_deferred() and add_data_deferred(),
 116                 // but wakeup is a pretty expensive operation, and the
 117                 // two threads might end up fighting over a lock, so it's
 118                 // seemingly (much) more efficient to just have a timeout here.
 119                 int nfds = epoll_pwait(epoll_fd, events, EPOLL_MAX_EVENTS, EPOLL_TIMEOUT_MS, &sigset_without_usr1_block);
 120                 if (nfds == -1 && errno != EINTR) {
 121                         log_perror("epoll_wait");
 122                         exit(1);
 123                 }
 124
 125                 lock_guard<mutex> lock(mu);  // We release the mutex between iterations.
 126
 127                 process_queued_data();
 128
 129                 // Process each client where we have socket activity.
 130                 for (int i = 0; i < nfds; ++i) {
 131                         Client *client = reinterpret_cast<Client *>(events[i].data.ptr);
 132
 133                         if (events[i].events & (EPOLLERR | EPOLLRDHUP | EPOLLHUP)) {
 134                                 close_client(client);
 135                                 continue;
 136                         }
 137
 138                         process_client(client);
 139                 }
 140
 141                 // Process each client where its stream has new data,
 142                 // even if there was no socket activity.
 143                 for (unique_ptr<Stream> &stream : streams) {
 144                         vector<Client *> to_process;
 145                         swap(stream->to_process, to_process);
 146                         for (Client *client : to_process) {
 147                                 process_client(client);
 148                         }
 149                 }
 150
 151                 // Finally, go through each client to see if it's timed out
 152                 // in the READING_REQUEST state. (Seemingly there are clients
 153                 // that can hold sockets up for days at a time without sending
 154                 // anything at all.)
 155                 timespec timeout_time;
 156                 if (clock_gettime(CLOCK_MONOTONIC_COARSE, &timeout_time) == -1) {
 157                         log_perror("clock_gettime(CLOCK_MONOTONIC_COARSE)");
 158                         continue;
 159                 }
 160                 timeout_time.tv_sec -= REQUEST_READ_TIMEOUT_SEC;
 161                 while (!clients_ordered_by_connect_time.empty()) {
 162                         const pair<timespec, int> &connect_time_and_fd = clients_ordered_by_connect_time.front();
 163
 164                         // See if we have reached the end of clients to process.
 165                         if (is_earlier(timeout_time, connect_time_and_fd.first)) {
 166                                 break;
 167                         }
 168
 169                         // If this client doesn't exist anymore, just ignore it
 170                         // (it was deleted earlier).
 171                         auto client_it = clients.find(connect_time_and_fd.second);
 172                         if (client_it == clients.end()) {
 173                                 clients_ordered_by_connect_time.pop();
 174                                 continue;
 175                         }
 176                         Client *client = &client_it->second;
 177                         if (!is_equal(client->connect_time, connect_time_and_fd.first)) {
 178                                 // Another client has taken this fd in the meantime.
 179                                 clients_ordered_by_connect_time.pop();
 180                                 continue;
 181                         }
 182
 183                         if (client->state != Client::READING_REQUEST) {
 184                                 // Only READING_REQUEST can time out.
 185                                 clients_ordered_by_connect_time.pop();
 186                                 continue;
 187                         }
 188
 189                         // OK, it timed out.
 190                         close_client(client);
 191                         clients_ordered_by_connect_time.pop();
 192                 }
 193         }
 194 }
 195
 196 CubemapStateProto Server::serialize(unordered_map<const string *, size_t> *short_response_pool)
 197 {
 198         // We don't serialize anything queued, so empty the queues.
 199         process_queued_data();
 200
 201         // Set all clients in a consistent state before serializing
 202         // (ie., they have no remaining lost data). Otherwise, increasing
 203         // the backlog could take clients into a newly valid area of the backlog,
 204         // sending a stream of zeros instead of skipping the data as it should.
 205         //
 206         // TODO: Do this when clients are added back from serialized state instead;
 207         // it would probably be less wasteful.
 208         for (auto &fd_and_client : clients) {
 209                 skip_lost_data(&fd_and_client.second);
 210         }
 211
 212         CubemapStateProto serialized;
 213         for (const auto &fd_and_client : clients) {
 214                 serialized.add_clients()->MergeFrom(fd_and_client.second.serialize(short_response_pool));
 215         }
 216         for (unique_ptr<Stream> &stream : streams) {
 217                 serialized.add_streams()->MergeFrom(stream->serialize());
 218         }
 219         for (const auto &key_and_zombie : hls_zombies) {
 220                 HLSZombieProto *proto = serialized.add_hls_zombies();
 221                 proto->set_key(key_and_zombie.first);
 222
 223                 const HLSZombie &zombie = key_and_zombie.second;
 224                 proto->set_remote_addr(zombie.remote_addr);
 225                 proto->set_url(zombie.url);
 226                 proto->set_referer(zombie.referer);
 227                 proto->set_user_agent(zombie.user_agent);
 228                 proto->set_expires_sec(zombie.expires.tv_sec);
 229                 proto->set_expires_nsec(zombie.expires.tv_nsec);
 230         }
 231         return serialized;
 232 }
 233
 234 void Server::add_client_deferred(int sock, Acceptor *acceptor)
 235 {
 236         lock_guard<mutex> lock(queued_clients_mutex);
 237         queued_add_clients.push_back(std::make_pair(sock, acceptor));
 238 }
 239
 240 void Server::add_client(int sock, Acceptor *acceptor)
 241 {
 242         const bool is_tls = acceptor->is_tls();
 243         auto inserted = clients.insert(make_pair(sock, Client(sock)));
 244         assert(inserted.second == true);  // Should not already exist.
 245         Client *client_ptr = &inserted.first->second;
 246
 247         start_client_timeout_timer(client_ptr);
 248
 249         // Start listening on data from this socket.
 250         epoll_event ev;
 251         if (is_tls) {
 252                 // Even in the initial state (READING_REQUEST), TLS needs to
 253                 // send data for the handshake, and thus might end up needing
 254                 // to know about EPOLLOUT.
 255                 ev.events = EPOLLIN | EPOLLOUT | EPOLLET | EPOLLRDHUP;
 256         } else {
 257                 // EPOLLOUT will be added once we go out of READING_REQUEST.
 258                 ev.events = EPOLLIN | EPOLLET | EPOLLRDHUP;
 259         }
 260         ev.data.ptr = client_ptr;
 261         if (epoll_ctl(epoll_fd, EPOLL_CTL_ADD, sock, &ev) == -1) {
 262                 log_perror("epoll_ctl(EPOLL_CTL_ADD)");
 263                 exit(1);
 264         }
 265
 266         if (is_tls) {
 267                 assert(tls_server_contexts.count(acceptor));
 268                 client_ptr->tls_context = tls_accept(tls_server_contexts[acceptor]);
 269                 if (client_ptr->tls_context == nullptr) {
 270                         log(ERROR, "tls_accept() failed");
 271                         close_client(client_ptr);
 272                         return;
 273                 }
 274                 tls_make_exportable(client_ptr->tls_context, 1);
 275         }
 276
 277         process_client(client_ptr);
 278 }
 279
 280 void Server::add_client_from_serialized(const ClientProto &client, const vector<shared_ptr<const string>> &short_responses)
 281 {
 282         lock_guard<mutex> lock(mu);
 283         Stream *stream;
 284         int stream_index = lookup_stream_by_url(client.url());
 285         if (stream_index == -1) {
 286                 assert(client.state() != Client::SENDING_DATA);
 287                 stream = nullptr;
 288         } else {
 289                 stream = streams[stream_index].get();
 290         }
 291         auto inserted = clients.insert(make_pair(client.sock(), Client(client, short_responses, stream)));
 292         assert(inserted.second == true);  // Should not already exist.
 293         Client *client_ptr = &inserted.first->second;
 294
 295         // Connection timestamps must be nondecreasing.
 296         assert(clients_ordered_by_connect_time.empty() ||
 297                !is_earlier(client_ptr->connect_time, clients_ordered_by_connect_time.back().first));
 298         clients_ordered_by_connect_time.push(make_pair(client_ptr->connect_time, client.sock()));
 299
 300         // Start listening on data from this socket.
 301         epoll_event ev;
 302         if (client.state() == Client::READING_REQUEST) {
 303                 // See the corresponding comment in Server::add_client().
 304                 if (client.has_tls_context()) {
 305                         ev.events = EPOLLIN | EPOLLOUT | EPOLLET | EPOLLRDHUP;
 306                 } else {
 307                         ev.events = EPOLLIN | EPOLLET | EPOLLRDHUP;
 308                 }
 309         } else {
 310                 // If we don't have more data for this client, we'll be putting it into
 311                 // the sleeping array again soon.
 312                 ev.events = EPOLLOUT | EPOLLET | EPOLLRDHUP;
 313         }
 314         ev.data.ptr = client_ptr;
 315         if (epoll_ctl(epoll_fd, EPOLL_CTL_ADD, client.sock(), &ev) == -1) {
 316                 log_perror("epoll_ctl(EPOLL_CTL_ADD)");
 317                 exit(1);
 318         }
 319
 320         if (client_ptr->state == Client::WAITING_FOR_KEYFRAME ||
 321             client_ptr->state == Client::PREBUFFERING ||
 322             (client_ptr->state == Client::SENDING_DATA &&
 323              client_ptr->stream_pos == client_ptr->stream->bytes_received)) {
 324                 client_ptr->stream->put_client_to_sleep(client_ptr);
 325         } else {
 326                 process_client(client_ptr);
 327         }
 328 }
 329
 330 void Server::start_client_timeout_timer(Client *client)
 331 {
 332         // Connection timestamps must be nondecreasing. I can't find any guarantee
 333         // that even the monotonic clock can't go backwards by a small amount
 334         // (think switching between CPUs with non-synchronized TSCs), so if
 335         // this actually should happen, we hack around it by fudging
 336         // connect_time.
 337         if (clock_gettime(CLOCK_MONOTONIC_COARSE, &client->connect_time) == -1) {
 338                 log_perror("clock_gettime(CLOCK_MONOTONIC_COARSE)");
 339         } else {
 340                 if (!clients_ordered_by_connect_time.empty() &&
 341                     is_earlier(client->connect_time, clients_ordered_by_connect_time.back().first)) {
 342                         client->connect_time = clients_ordered_by_connect_time.back().first;
 343                 }
 344                 clients_ordered_by_connect_time.push(make_pair(client->connect_time, client->sock));
 345         }
 346 }
 347
 348 int Server::lookup_stream_by_url(const string &url) const
 349 {
 350         const auto stream_url_it = stream_url_map.find(url);
 351         if (stream_url_it == stream_url_map.end()) {
 352                 return -1;
 353         }
 354         return stream_url_it->second;
 355 }
 356
 357 int Server::add_stream(const string &url,
 358                        const string &hls_url,
 359                        size_t backlog_size,
 360                        size_t prebuffering_bytes,
 361                        Stream::Encoding encoding,
 362                        Stream::Encoding src_encoding,
 363                        unsigned hls_frag_duration,
 364                        size_t hls_backlog_margin,
 365                        const string &allow_origin)
 366 {
 367         lock_guard<mutex> lock(mu);
 368         stream_url_map.insert(make_pair(url, streams.size()));
 369         if (!hls_url.empty()) {
 370                 stream_hls_url_map.insert(make_pair(hls_url, streams.size()));
 371         }
 372         streams.emplace_back(new Stream(url, backlog_size, prebuffering_bytes, encoding, src_encoding, hls_frag_duration, hls_backlog_margin, allow_origin));
 373         return streams.size() - 1;
 374 }
 375
 376 int Server::add_stream_from_serialized(const StreamProto &stream, int data_fd)
 377 {
 378         lock_guard<mutex> lock(mu);
 379         stream_url_map.insert(make_pair(stream.url(), streams.size()));
 380         // stream_hls_url_map will be updated in register_hls_url(), since it is not part
 381         // of the serialized state (it will always be picked out from the configuration).
 382         streams.emplace_back(new Stream(stream, data_fd));
 383         return streams.size() - 1;
 384 }
 385
 386 void Server::add_hls_zombie_from_serialized(const HLSZombieProto &zombie_proto)
 387 {
 388         lock_guard<mutex> lock(mu);
 389         HLSZombie zombie;
 390         zombie.remote_addr = zombie_proto.remote_addr();
 391         zombie.url = zombie_proto.url();
 392         zombie.referer = zombie_proto.referer();
 393         zombie.user_agent = zombie_proto.user_agent();
 394         zombie.expires.tv_sec = zombie_proto.expires_sec();
 395         zombie.expires.tv_nsec = zombie_proto.expires_nsec();
 396         hls_zombies[zombie_proto.key()] = move(zombie);
 397 }
 398
 399 void Server::set_backlog_size(int stream_index, size_t new_size)
 400 {
 401         lock_guard<mutex> lock(mu);
 402         assert(stream_index >= 0 && stream_index < ssize_t(streams.size()));
 403         streams[stream_index]->set_backlog_size(new_size);
 404 }
 405
 406 void Server::set_prebuffering_bytes(int stream_index, size_t new_amount)
 407 {
 408         lock_guard<mutex> lock(mu);
 409         assert(stream_index >= 0 && stream_index < ssize_t(streams.size()));
 410         streams[stream_index]->prebuffering_bytes = new_amount;
 411 }
 412
 413 void Server::set_encoding(int stream_index, Stream::Encoding encoding)
 414 {
 415         lock_guard<mutex> lock(mu);
 416         assert(stream_index >= 0 && stream_index < ssize_t(streams.size()));
 417         streams[stream_index]->encoding = encoding;
 418 }
 419
 420 void Server::set_src_encoding(int stream_index, Stream::Encoding encoding)
 421 {
 422         lock_guard<mutex> lock(mu);
 423         assert(stream_index >= 0 && stream_index < ssize_t(streams.size()));
 424         streams[stream_index]->src_encoding = encoding;
 425 }
 426
 427 void Server::set_hls_frag_duration(int stream_index, unsigned hls_frag_duration)
 428 {
 429         lock_guard<mutex> lock(mu);
 430         assert(stream_index >= 0 && stream_index < ssize_t(streams.size()));
 431         streams[stream_index]->hls_frag_duration = hls_frag_duration;
 432 }
 433
 434 void Server::set_hls_backlog_margin(int stream_index, size_t hls_backlog_margin)
 435 {
 436         lock_guard<mutex> lock(mu);
 437         assert(stream_index >= 0 && stream_index < ssize_t(streams.size()));
 438         assert(hls_backlog_margin >= 0);
 439         assert(hls_backlog_margin < streams[stream_index]->backlog_size);
 440         streams[stream_index]->hls_backlog_margin = hls_backlog_margin;
 441 }
 442
 443 void Server::set_allow_origin(int stream_index, const string &allow_origin)
 444 {
 445         lock_guard<mutex> lock(mu);
 446         assert(stream_index >= 0 && stream_index < ssize_t(streams.size()));
 447         streams[stream_index]->allow_origin = allow_origin;
 448 }
 449
 450 void Server::register_hls_url(int stream_index, const string &hls_url)
 451 {
 452         lock_guard<mutex> lock(mu);
 453         assert(stream_index >= 0 && stream_index < ssize_t(streams.size()));
 454         assert(!hls_url.empty());
 455         stream_hls_url_map.insert(make_pair(hls_url, stream_index));
 456 }
 457
 458 void Server::set_header(int stream_index, const string &http_header, const string &stream_header)
 459 {
 460         lock_guard<mutex> lock(mu);
 461         assert(stream_index >= 0 && stream_index < ssize_t(streams.size()));
 462         Stream *stream = streams[stream_index].get();
 463         stream->http_header = http_header;
 464
 465         if (stream_header != stream->stream_header) {
 466                 // We cannot start at any of the older starting points anymore,
 467                 // since they'd get the wrong header for the stream (not to mention
 468                 // that a changed header probably means the stream restarted,
 469                 // which means any client starting on the old one would probably
 470                 // stop playing properly at the change point). Next block
 471                 // should be a suitable starting point (if not, something is
 472                 // pretty strange), so it will fill up again soon enough.
 473                 stream->suitable_starting_points.clear();
 474
 475                 if (!stream->fragments.empty()) {
 476                         stream->fragments.clear();
 477                         ++stream->discontinuity_counter;
 478                         stream->clear_hls_playlist_cache();
 479                 }
 480         }
 481         stream->stream_header = stream_header;
 482 }
 483
 484 void Server::set_pacing_rate(int stream_index, uint32_t pacing_rate)
 485 {
 486         lock_guard<mutex> lock(mu);
 487         assert(clients.empty());
 488         assert(stream_index >= 0 && stream_index < ssize_t(streams.size()));
 489         streams[stream_index]->pacing_rate = pacing_rate;
 490 }
 491
 492 void Server::add_gen204(const std::string &url, const std::string &allow_origin)
 493 {
 494         lock_guard<mutex> lock(mu);
 495         assert(clients.empty());
 496         ping_url_map[url] = allow_origin;
 497 }
 498
 499 void Server::create_tls_context_for_acceptor(const Acceptor *acceptor)
 500 {
 501         assert(acceptor->is_tls());
 502
 503         bool is_server = true;
 504         TLSContext *server_context = tls_create_context(is_server, TLS_V12);
 505
 506         const string &cert = acceptor->get_certificate_chain();
 507         int num_cert = tls_load_certificates(server_context, reinterpret_cast<const unsigned char *>(cert.data()), cert.size());
 508         assert(num_cert > 0);  // Should have been checked by config earlier.
 509
 510         const string &key = acceptor->get_private_key();
 511         int num_key = tls_load_private_key(server_context, reinterpret_cast<const unsigned char *>(key.data()), key.size());
 512         assert(num_key > 0);  // Should have been checked by config earlier.
 513
 514         tls_server_contexts.insert(make_pair(acceptor, server_context));
 515 }
 516
 517 void Server::add_data_deferred(int stream_index, const char *data, size_t bytes, uint16_t metacube_flags, const RationalPTS &pts)
 518 {
 519         assert(stream_index >= 0 && stream_index < ssize_t(streams.size()));
 520         streams[stream_index]->add_data_deferred(data, bytes, metacube_flags, pts);
 521 }
 522
 523 // See the .h file for postconditions after this function.
 524 void Server::process_client(Client *client)
 525 {
 526         switch (client->state) {
 527         case Client::READING_REQUEST: {
 528                 if (client->tls_context != nullptr && !client->in_ktls_mode) {
 529                         if (send_pending_tls_data(client)) {
 530                                 // send_pending_tls_data() hit postconditions #1 or #4.
 531                                 return;
 532                         }
 533                 }
 534
 535 read_request_again:
 536                 // Try to read more of the request.
 537                 char buf[1024];
 538                 int ret;
 539                 if (client->tls_context == nullptr || client->in_ktls_mode) {
 540                         ret = read_plain_data(client, buf, sizeof(buf));
 541                         if (ret == -1) {
 542                                 // read_plain_data() hit postconditions #1 or #2.
 543                                 return;
 544                         }
 545                 } else {
 546                         ret = read_tls_data(client, buf, sizeof(buf));
 547                         if (ret == -1) {
 548                                 // read_tls_data() hit postconditions #1, #2 or #4.
 549                                 return;
 550                         }
 551                 }
 552
 553                 RequestParseStatus status = wait_for_double_newline(&client->request, buf, ret);
 554
 555                 switch (status) {
 556                 case RP_OUT_OF_SPACE:
 557                         log(WARNING, "[%s] Client sent overlong request!", client->remote_addr.c_str());
 558                         close_client(client);
 559                         return;
 560                 case RP_NOT_FINISHED_YET:
 561                         // OK, we don't have the entire header yet. Fine; we'll get it later.
 562                         // See if there's more data for us.
 563                         goto read_request_again;
 564                 case RP_EXTRA_DATA:
 565                         log(WARNING, "[%s] Junk data after request!", client->remote_addr.c_str());
 566                         close_client(client);
 567                         return;
 568                 case RP_FINISHED:
 569                         break;
 570                 }
 571
 572                 assert(status == RP_FINISHED);
 573
 574                 int error_code = parse_request(client);
 575                 if (error_code == 200) {
 576                         if (client->serving_hls_playlist) {
 577                                 construct_hls_playlist(client);
 578                         } else {
 579                                 construct_stream_header(client);
 580                         }
 581                 } else if (error_code == 204) {
 582                         construct_204(client);
 583                 } else {
 584                         construct_error(client, error_code);
 585                 }
 586
 587                 // We've changed states, so fall through.
 588                 assert(client->state == Client::SENDING_SHORT_RESPONSE ||
 589                        client->state == Client::SENDING_HEADER);
 590         }
 591         case Client::SENDING_SHORT_RESPONSE:
 592         case Client::SENDING_HEADER: {
 593 sending_header_or_short_response_again:
 594                 int ret;
 595                 do {
 596                         ret = write(client->sock,
 597                                     client->header_or_short_response->data() + client->header_or_short_response_bytes_sent,
 598                                     client->header_or_short_response->size() - client->header_or_short_response_bytes_sent);
 599                 } while (ret == -1 && errno == EINTR);
 600
 601                 if (ret == -1 && errno == EAGAIN) {
 602                         // We're out of socket space, so now we're at the “low edge” of epoll's
 603                         // edge triggering. epoll will tell us when there is more room, so for now,
 604                         // just return.
 605                         // This is postcondition #4.
 606                         return;
 607                 }
 608
 609                 if (ret == -1) {
 610                         // Error! Postcondition #1.
 611                         log_perror("write");
 612                         close_client(client);
 613                         return;
 614                 }
 615
 616                 client->header_or_short_response_bytes_sent += ret;
 617                 assert(client->header_or_short_response_bytes_sent <= client->header_or_short_response->size());
 618
 619                 if (client->header_or_short_response_bytes_sent < client->header_or_short_response->size()) {
 620                         // We haven't sent all yet. Fine; go another round.
 621                         goto sending_header_or_short_response_again;
 622                 }
 623
 624                 // We're done sending the header or error! Clear it to release some memory.
 625                 client->header_or_short_response = nullptr;
 626                 client->header_or_short_response_holder.clear();
 627                 client->header_or_short_response_ref.reset();
 628
 629                 if (client->state == Client::SENDING_SHORT_RESPONSE) {
 630                         if (more_requests(client)) {
 631                                 // We're done sending the error, but should keep on reading new requests.
 632                                 goto read_request_again;
 633                         } else {
 634                                 // We're done sending the error, so now close.
 635                                 // This is postcondition #1.
 636                                 close_client(client);
 637                         }
 638                         return;
 639                 }
 640
 641                 Stream *stream = client->stream;
 642                 hls_zombies.erase(client->get_hls_zombie_key());
 643                 if (client->stream_pos == Client::STREAM_POS_AT_START) {
 644                         // Start sending from the beginning of the backlog.
 645                         client->stream_pos = min<size_t>(
 646                             stream->bytes_received - stream->backlog_size,
 647                             0);
 648                         client->state = Client::SENDING_DATA;
 649                         goto sending_data;
 650                 } else if (client->stream_pos_end != Client::STREAM_POS_NO_END) {
 651                         // We're sending a fragment, and should have all of it,
 652                         // so start sending right away.
 653                         assert(client->stream_pos >= 0);
 654                         client->state = Client::SENDING_DATA;
 655                         goto sending_data;
 656                 } else if (stream->prebuffering_bytes == 0) {
 657                         // Start sending from the first keyframe we get. In other
 658                         // words, we won't send any of the backlog, but we'll start
 659                         // sending immediately as we get the next keyframe block.
 660                         // Note that this is functionally identical to the next if branch,
 661                         // except that we save a binary search.
 662                         assert(client->stream_pos == Client::STREAM_POS_AT_END);
 663                         assert(client->stream_pos_end == Client::STREAM_POS_NO_END);
 664                         client->stream_pos = stream->bytes_received;
 665                         client->state = Client::WAITING_FOR_KEYFRAME;
 666                 } else {
 667                         // We're not going to send anything to the client before we have
 668                         // N bytes. However, this wait might be boring; we can just as well
 669                         // use it to send older data if we have it. We use lower_bound()
 670                         // so that we are conservative and never add extra latency over just
 671                         // waiting (assuming CBR or nearly so); otherwise, we could want e.g.
 672                         // 100 kB prebuffer but end up sending a 10 MB GOP.
 673                         assert(client->stream_pos == Client::STREAM_POS_AT_END);
 674                         assert(client->stream_pos_end == Client::STREAM_POS_NO_END);
 675                         deque<size_t>::const_iterator starting_point_it =
 676                                 lower_bound(stream->suitable_starting_points.begin(),
 677                                             stream->suitable_starting_points.end(),
 678                                             stream->bytes_received - stream->prebuffering_bytes);
 679                         if (starting_point_it == stream->suitable_starting_points.end()) {
 680                                 // None found. Just put us at the end, and then wait for the
 681                                 // first keyframe to appear.
 682                                 client->stream_pos = stream->bytes_received;
 683                                 client->state = Client::WAITING_FOR_KEYFRAME;
 684                         } else {
 685                                 client->stream_pos = *starting_point_it;
 686                                 client->state = Client::PREBUFFERING;
 687                                 goto prebuffering;
 688                         }
 689                 }
 690                 // Fall through.
 691         }
 692         case Client::WAITING_FOR_KEYFRAME: {
 693                 Stream *stream = client->stream;
 694                 if (stream->suitable_starting_points.empty() ||
 695                     client->stream_pos > stream->suitable_starting_points.back()) {
 696                         // We haven't received a keyframe since this stream started waiting,
 697                         // so keep on waiting for one.
 698                         // This is postcondition #3.
 699                         stream->put_client_to_sleep(client);
 700                         return;
 701                 }
 702                 client->stream_pos = stream->suitable_starting_points.back();
 703                 client->state = Client::PREBUFFERING;
 704                 // Fall through.
 705         }
 706         case Client::PREBUFFERING: {
 707 prebuffering:
 708                 Stream *stream = client->stream;
 709                 size_t bytes_to_send = stream->bytes_received - client->stream_pos;
 710                 assert(bytes_to_send <= stream->backlog_size);
 711                 if (bytes_to_send < stream->prebuffering_bytes) {
 712                         // We don't have enough bytes buffered to start this client yet.
 713                         // This is postcondition #3.
 714                         stream->put_client_to_sleep(client);
 715                         return;
 716                 }
 717                 client->state = Client::SENDING_DATA;
 718                 // Fall through.
 719         }
 720         case Client::SENDING_DATA: {
 721 sending_data:
 722                 skip_lost_data(client);
 723                 Stream *stream = client->stream;
 724
 725 sending_data_again:
 726                 size_t bytes_to_send;
 727                 if (client->stream_pos_end == Client::STREAM_POS_NO_END) {
 728                          bytes_to_send = stream->bytes_received - client->stream_pos;
 729                 } else {
 730                          bytes_to_send = client->stream_pos_end - client->stream_pos;
 731                 }
 732                 assert(bytes_to_send <= stream->backlog_size);
 733                 if (bytes_to_send == 0) {
 734                         if (client->stream_pos == client->stream_pos_end) {  // We have a definite end, and we're at it.
 735                                 // Add (or overwrite) a HLS zombie.
 736                                 timespec now;
 737                                 if (clock_gettime(CLOCK_MONOTONIC_COARSE, &now) == -1) {
 738                                         log_perror("clock_gettime(CLOCK_MONOTONIC_COARSE)");
 739                                 } else {
 740                                         HLSZombie zombie;
 741                                         zombie.remote_addr = client->remote_addr;
 742                                         zombie.referer = client->referer;
 743                                         zombie.user_agent = client->user_agent;
 744                                         zombie.url = client->stream->url + "?frag=<idle>";
 745                                         zombie.expires = now;
 746                                         zombie.expires.tv_sec += client->stream->hls_frag_duration * 3;
 747                                         hls_zombies[client->get_hls_zombie_key()] = move(zombie);
 748                                 }
 749                                 if (more_requests(client)) {
 750                                         // We're done sending the fragment, but should keep on reading new requests.
 751                                         goto read_request_again;
 752                                 } else {
 753                                         // We're done sending the fragment, so now close.
 754                                         // This is postcondition #1.
 755                                         close_client(client);
 756                                 }
 757                         }
 758                         return;
 759                 }
 760
 761                 // See if we need to split across the circular buffer.
 762                 bool more_data = false;
 763                 if ((client->stream_pos % stream->backlog_size) + bytes_to_send > stream->backlog_size) {
 764                         bytes_to_send = stream->backlog_size - (client->stream_pos % stream->backlog_size);
 765                         more_data = true;
 766                 }
 767
 768                 ssize_t ret;
 769                 do {
 770                         off_t offset = client->stream_pos % stream->backlog_size;
 771                         ret = sendfile(client->sock, stream->data_fd, &offset, bytes_to_send);
 772                 } while (ret == -1 && errno == EINTR);
 773
 774                 if (ret == -1 && errno == EAGAIN) {
 775                         // We're out of socket space, so return; epoll will wake us up
 776                         // when there is more room.
 777                         // This is postcondition #4.
 778                         return;
 779                 }
 780                 if (ret == -1) {
 781                         // Error, close; postcondition #1.
 782                         log_perror("sendfile");
 783                         close_client(client);
 784                         return;
 785                 }
 786                 client->stream_pos += ret;
 787                 client->bytes_sent += ret;
 788
 789                 assert(client->stream_pos_end == Client::STREAM_POS_NO_END || client->stream_pos <= client->stream_pos_end);
 790                 if (client->stream_pos == client->stream_pos_end) {
 791                         goto sending_data_again;  // Will see that bytes_to_send == 0 and end.
 792                 } else if (client->stream_pos == stream->bytes_received) {
 793                         // We don't have any more data for this client, so put it to sleep.
 794                         // This is postcondition #3.
 795                         stream->put_client_to_sleep(client);
 796                 } else if (more_data && size_t(ret) == bytes_to_send) {
 797                         goto sending_data_again;
 798                 }
 799                 // We'll also get here for postcondition #4 (similar to the EAGAIN path above).
 800                 break;
 801         }
 802         default:
 803                 assert(false);
 804         }
 805 }
 806
 807 namespace {
 808
 809 void flush_pending_data(int sock)
 810 {
 811         // Flush pending data, which would otherwise wait for the 200ms TCP_CORK timer
 812         // to elapsed; does not cancel out TCP_CORK (since that still takes priority),
 813         // but does a one-off flush.
 814         int one = 1;
 815         if (setsockopt(sock, SOL_TCP, TCP_NODELAY, &one, sizeof(one)) == -1) {
 816                 log_perror("setsockopt(TCP_NODELAY)");
 817                 // Can still continue.
 818         }
 819 }
 820
 821 }  // namespace
 822
 823 bool Server::send_pending_tls_data(Client *client)
 824 {
 825         // See if there's data from the TLS library to write.
 826         if (client->tls_data_to_send == nullptr) {
 827                 client->tls_data_to_send = tls_get_write_buffer(client->tls_context, &client->tls_data_left_to_send);
 828                 if (client->tls_data_to_send == nullptr) {
 829                         // Really no data to send.
 830                         return false;
 831                 }
 832         }
 833
 834 send_data_again:
 835         int ret;
 836         do {
 837                 ret = write(client->sock, client->tls_data_to_send, client->tls_data_left_to_send);
 838         } while (ret == -1 && errno == EINTR);
 839         assert(ret < 0 || size_t(ret) <= client->tls_data_left_to_send);
 840
 841         if (ret == -1 && errno == EAGAIN) {
 842                 // We're out of socket space, so now we're at the “low edge” of epoll's
 843                 // edge triggering. epoll will tell us when there is more room, so for now,
 844                 // just return.
 845                 // This is postcondition #4.
 846                 return true;
 847         }
 848         if (ret == -1) {
 849                 // Error! Postcondition #1.
 850                 log_perror("write");
 851                 close_client(client);
 852                 return true;
 853         }
 854         if (ret > 0 && size_t(ret) == client->tls_data_left_to_send) {
 855                 // All data has been sent, so we don't need to go to sleep
 856                 // (although we are likely to do so immediately afterwards,
 857                 // due to lack of client data).
 858                 tls_buffer_clear(client->tls_context);
 859                 client->tls_data_to_send = nullptr;
 860
 861                 // Flush the data we just wrote, since the client probably
 862                 // is waiting for it.
 863                 flush_pending_data(client->sock);
 864                 return false;
 865         }
 866
 867         // More data to send, so try again.
 868         client->tls_data_to_send += ret;
 869         client->tls_data_left_to_send -= ret;
 870         goto send_data_again;
 871 }
 872
 873 int Server::read_plain_data(Client *client, char *buf, size_t max_size)
 874 {
 875         int ret;
 876         do {
 877                 ret = read(client->sock, buf, max_size);
 878         } while (ret == -1 && errno == EINTR);
 879
 880         if (ret == -1 && errno == EAGAIN) {
 881                 // No more data right now. Nothing to do.
 882                 // This is postcondition #2.
 883                 return -1;
 884         }
 885         if (ret == -1) {
 886                 log_perror("read");
 887                 close_client(client);
 888                 return -1;
 889         }
 890         if (ret == 0) {
 891                 // OK, the socket is closed.
 892                 close_client(client);
 893                 return -1;
 894         }
 895
 896         return ret;
 897 }
 898
 899 int Server::read_tls_data(Client *client, char *buf, size_t max_size)
 900 {
 901 read_again:
 902         assert(!client->in_ktls_mode);
 903
 904         int ret;
 905         do {
 906                 ret = read(client->sock, buf, max_size);
 907         } while (ret == -1 && errno == EINTR);
 908
 909         if (ret == -1 && errno == EAGAIN) {
 910                 // No more data right now. Nothing to do.
 911                 // This is postcondition #2.
 912                 return -1;
 913         }
 914         if (ret == -1) {
 915                 log_perror("read");
 916                 close_client(client);
 917                 return -1;
 918         }
 919         if (ret == 0) {
 920                 // OK, the socket is closed.
 921                 close_client(client);
 922                 return -1;
 923         }
 924
 925         // Give it to the TLS library.
 926         int err = tls_consume_stream(client->tls_context, reinterpret_cast<const unsigned char *>(buf), ret, nullptr);
 927         if (err < 0) {
 928                 log_tls_error("tls_consume_stream", err);
 929                 close_client(client);
 930                 return -1;
 931         }
 932         if (err == 0) {
 933                 // Not consumed any data. See if we can read more.
 934                 goto read_again;
 935         }
 936
 937         // Read any decrypted data available for us. (We can reuse buf, since it's free now.)
 938         ret = tls_read(client->tls_context, reinterpret_cast<unsigned char *>(buf), max_size);
 939         if (ret == 0) {
 940                 // No decrypted data for us yet, but there might be some more handshaking
 941                 // to send. Do that if needed, then look for more data.
 942                 if (send_pending_tls_data(client)) {
 943                         // send_pending_tls_data() hit postconditions #1 or #4.
 944                         return -1;
 945                 }
 946                 goto read_again;
 947         }
 948         if (ret < 0) {
 949                 log_tls_error("tls_read", ret);
 950                 close_client(client);
 951                 return -1;
 952         }
 953
 954         if (tls_established(client->tls_context)) {
 955                 // We're ready to enter kTLS mode, unless we still have some
 956                 // handshake data to send (which then must be sent as non-kTLS).
 957                 if (send_pending_tls_data(client)) {
 958                         // send_pending_tls_data() hit postconditions #1 or #4.
 959                         return -1;
 960                 }
 961                 int err = tls_make_ktls(client->tls_context, client->sock);  // Don't overwrite ret.
 962                 if (err < 0) {
 963                         log_tls_error("tls_make_ktls", ret);
 964                         close_client(client);
 965                         return -1;
 966                 }
 967                 client->in_ktls_mode = true;
 968         }
 969
 970         assert(ret > 0);
 971         return ret;
 972 }
 973
 974 // See if there's some data we've lost. Ideally, we should drop to a block boundary,
 975 // but resync will be the mux's problem.
 976 void Server::skip_lost_data(Client *client)
 977 {
 978         Stream *stream = client->stream;
 979         if (stream == nullptr) {
 980                 return;
 981         }
 982         size_t bytes_to_send = stream->bytes_received - client->stream_pos;
 983         if (bytes_to_send > stream->backlog_size) {
 984                 size_t bytes_lost = bytes_to_send - stream->backlog_size;
 985                 client->bytes_lost += bytes_lost;
 986                 ++client->num_loss_events;
 987                 if (!client->close_after_response) {
 988                         assert(client->stream_pos_end != Client::STREAM_POS_NO_END);
 989
 990                         // We've already sent a Content-Length, so we can't just skip data.
 991                         // Close the connection immediately and hope the other side
 992                         // is able to figure out that there was an error and it needs to skip.
 993                         client->close_after_response = true;
 994                         client->stream_pos = client->stream_pos_end;
 995                 } else {
 996                         client->stream_pos = stream->bytes_received - stream->backlog_size;
 997                 }
 998         }
 999 }
1000
1001 int Server::parse_request(Client *client)
1002 {
1003         vector<string> lines = split_lines(client->request);
1004         client->request.clear();
1005         if (lines.empty()) {
1006                 return 400;  // Bad request (empty).
1007         }
1008
1009         // Parse the headers, for logging purposes.
1010         HTTPHeaderMultimap headers = extract_headers(lines, client->remote_addr);
1011         const auto referer_it = headers.find("Referer");
1012         if (referer_it != headers.end()) {
1013                 client->referer = referer_it->second;
1014         }
1015         const auto user_agent_it = headers.find("User-Agent");
1016         if (user_agent_it != headers.end()) {
1017                 client->user_agent = user_agent_it->second;
1018         }
1019         const auto x_playback_session_id_it = headers.find("X-Playback-Session-Id");
1020         if (x_playback_session_id_it != headers.end()) {
1021                 client->x_playback_session_id = x_playback_session_id_it->second;
1022         } else {
1023                 client->x_playback_session_id.clear();
1024         }
1025
1026         vector<string> request_tokens = split_tokens(lines[0]);
1027         if (request_tokens.size() < 3) {
1028                 return 400;  // Bad request (empty).
1029         }
1030         if (request_tokens[0] != "GET") {
1031                 return 400;  // Should maybe be 405 instead?
1032         }
1033
1034         string url = request_tokens[1];
1035         client->url = url;
1036         if (url.size() > 8 && url.find("?backlog") == url.size() - 8) {
1037                 client->stream_pos = Client::STREAM_POS_AT_START;
1038                 url = url.substr(0, url.size() - 8);
1039         } else {
1040                 size_t pos = url.find("?frag=");
1041                 if (pos != string::npos) {
1042                         // Parse an endpoint of the type /stream.mp4?frag=1234-5678.
1043                         const char *ptr = url.c_str() + pos + 6;
1044
1045                         // "?frag=header" is special.
1046                         if (strcmp(ptr, "header") == 0) {
1047                                 client->stream_pos = Client::STREAM_POS_HEADER_ONLY;
1048                                 client->stream_pos_end = -1;
1049                         } else {
1050                                 char *endptr;
1051                                 long long frag_start = strtol(ptr, &endptr, 10);
1052                                 if (ptr == endptr || frag_start < 0 || frag_start == LLONG_MAX) {
1053                                         return 400;  // Bad request.
1054                                 }
1055                                 if (*endptr != '-') {
1056                                         return 400;  // Bad request.
1057                                 }
1058                                 ptr = endptr + 1;
1059
1060                                 long long frag_end = strtol(ptr, &endptr, 10);
1061                                 if (ptr == endptr || frag_end < frag_start || frag_end == LLONG_MAX) {
1062                                         return 400;  // Bad request.
1063                                 }
1064
1065                                 if (*endptr != '\0') {
1066                                         return 400;  // Bad request.
1067                                 }
1068
1069                                 client->stream_pos = frag_start;
1070                                 client->stream_pos_end = frag_end;
1071                         }
1072                         url = url.substr(0, pos);
1073                 } else {
1074                         client->stream_pos = -1;
1075                         client->stream_pos_end = -1;
1076                 }
1077         }
1078
1079         // Figure out if we're supposed to close the socket after we've delivered the response.
1080         string protocol = request_tokens[2];
1081         if (protocol.find("HTTP/") != 0) {
1082                 return 400;  // Bad request.
1083         }
1084         client->close_after_response = false;
1085         client->http_11 = true;
1086         if (protocol == "HTTP/1.0") {
1087                 // No persistent connections.
1088                 client->close_after_response = true;
1089                 client->http_11 = false;
1090         } else {
1091                 const auto connection_it = headers.find("Connection");
1092                 if (connection_it != headers.end() && connection_it->second == "close") {
1093                         client->close_after_response = true;
1094                 }
1095         }
1096
1097         const auto stream_url_map_it = stream_url_map.find(url);
1098         if (stream_url_map_it != stream_url_map.end()) {
1099                 // Serve a regular stream..
1100                 client->stream = streams[stream_url_map_it->second].get();
1101                 client->serving_hls_playlist = false;
1102         } else {
1103                 const auto stream_hls_url_map_it = stream_hls_url_map.find(url);
1104                 if (stream_hls_url_map_it != stream_hls_url_map.end()) {
1105                         // Serve HLS playlist.
1106                         client->stream = streams[stream_hls_url_map_it->second].get();
1107                         client->serving_hls_playlist = true;
1108                 } else {
1109                         const auto ping_url_map_it = ping_url_map.find(url);
1110                         if (ping_url_map_it == ping_url_map.end()) {
1111                                 return 404;  // Not found.
1112                         } else {
1113                                 // Serve a ping (204 no error).
1114                                 return 204;
1115                         }
1116                 }
1117         }
1118
1119         Stream *stream = client->stream;
1120         if (stream->http_header.empty()) {
1121                 return 503;  // Service unavailable.
1122         }
1123
1124         if (client->serving_hls_playlist) {
1125                 if (stream->encoding == Stream::STREAM_ENCODING_METACUBE) {
1126                         // This doesn't make any sense, and is hard to implement, too.
1127                         return 404;
1128                 } else {
1129                         return 200;
1130                 }
1131         }
1132
1133         if (client->stream_pos_end == Client::STREAM_POS_NO_END) {
1134                 // This stream won't end, so we don't have a content-length,
1135                 // and can just as well tell the client it's Connection: close
1136                 // (otherwise, we'd have to implement chunking TE for no good reason).
1137                 client->close_after_response = true;
1138         } else {
1139                 if (stream->encoding == Stream::STREAM_ENCODING_METACUBE) {
1140                         // This doesn't make any sense, and is hard to implement, too.
1141                         return 416;  // Range not satisfiable.
1142                 }
1143
1144                 // Check that we have the requested fragment in our backlog.
1145                 size_t buffer_end = stream->bytes_received;
1146                 size_t buffer_start = (buffer_end <= stream->backlog_size) ? 0 : buffer_end - stream->backlog_size;
1147
1148                 if (client->stream_pos_end > buffer_end ||
1149                     client->stream_pos < buffer_start) {
1150                         return 416;  // Range not satisfiable.
1151                 }
1152         }
1153
1154         client->stream = stream;
1155         if (setsockopt(client->sock, SOL_SOCKET, SO_MAX_PACING_RATE, &client->stream->pacing_rate, sizeof(client->stream->pacing_rate)) == -1) {
1156                 if (client->stream->pacing_rate != ~0U) {
1157                         log_perror("setsockopt(SO_MAX_PACING_RATE)");
1158                 }
1159         }
1160         client->request.clear();
1161
1162         return 200;  // OK!
1163 }
1164
1165 void Server::construct_stream_header(Client *client)
1166 {
1167         Stream *stream = client->stream;
1168         string response = stream->http_header;
1169         if (client->stream_pos == Client::STREAM_POS_HEADER_ONLY) {
1170                 char buf[64];
1171                 snprintf(buf, sizeof(buf), "Content-Length: %zu\r\n", stream->stream_header.size());
1172                 response.append(buf);
1173         } else if (client->stream_pos_end != Client::STREAM_POS_NO_END) {
1174                 char buf[64];
1175                 snprintf(buf, sizeof(buf), "Content-Length: %" PRIu64 "\r\n", client->stream_pos_end - client->stream_pos);
1176                 response.append(buf);
1177         }
1178         if (client->http_11) {
1179                 assert(response.find("HTTP/1.0") == 0);
1180                 response[7] = '1';  // Change to HTTP/1.1.
1181                 if (client->close_after_response) {
1182                         response.append("Connection: close\r\n");
1183                 }
1184         } else {
1185                 assert(client->close_after_response);
1186         }
1187         if (!stream->allow_origin.empty()) {
1188                 response.append("Access-Control-Allow-Origin: ");
1189                 response.append(stream->allow_origin);
1190                 response.append("\r\n");
1191         }
1192         if (stream->encoding == Stream::STREAM_ENCODING_RAW) {
1193                 response.append("\r\n");
1194         } else if (stream->encoding == Stream::STREAM_ENCODING_METACUBE) {
1195                 response.append("Content-Encoding: metacube\r\n\r\n");
1196                 if (!stream->stream_header.empty()) {
1197                         metacube2_block_header hdr;
1198                         memcpy(hdr.sync, METACUBE2_SYNC, sizeof(hdr.sync));
1199                         hdr.size = htonl(stream->stream_header.size());
1200                         hdr.flags = htons(METACUBE_FLAGS_HEADER);
1201                         hdr.csum = htons(metacube2_compute_crc(&hdr));
1202                         response.append(string(reinterpret_cast<char *>(&hdr), sizeof(hdr)));
1203                 }
1204         } else {
1205                 assert(false);
1206         }
1207         if (client->stream_pos == Client::STREAM_POS_HEADER_ONLY) {
1208                 client->state = Client::SENDING_SHORT_RESPONSE;
1209                 response.append(stream->stream_header);
1210         } else {
1211                 client->state = Client::SENDING_HEADER;
1212                 if (client->stream_pos_end == Client::STREAM_POS_NO_END) {  // Fragments don't contain stream headers.
1213                         response.append(stream->stream_header);
1214                 }
1215         }
1216
1217         client->header_or_short_response_holder = move(response);
1218         client->header_or_short_response = &client->header_or_short_response_holder;
1219
1220         // Switch states.
1221         change_epoll_events(client, EPOLLOUT | EPOLLET | EPOLLRDHUP);
1222 }
1223
1224 void Server::construct_error(Client *client, int error_code)
1225 {
1226         char error[256];
1227         if (client->http_11 && client->close_after_response) {
1228                 snprintf(error, sizeof(error),
1229                         "HTTP/1.1 %d Error\r\nContent-Type: text/plain\r\nConnection: close\r\n\r\nSomething went wrong. Sorry.\r\n",
1230                         error_code);
1231         } else {
1232                 snprintf(error, sizeof(error),
1233                         "HTTP/1.%d %d Error\r\nContent-Type: text/plain\r\nContent-Length: 30\r\n\r\nSomething went wrong. Sorry.\r\n",
1234                         client->http_11, error_code);
1235         }
1236         client->header_or_short_response_holder = error;
1237         client->header_or_short_response = &client->header_or_short_response_holder;
1238
1239         // Switch states.
1240         client->state = Client::SENDING_SHORT_RESPONSE;
1241         change_epoll_events(client, EPOLLOUT | EPOLLET | EPOLLRDHUP);
1242 }
1243
1244 void Server::construct_hls_playlist(Client *client)
1245 {
1246         Stream *stream = client->stream;
1247         shared_ptr<const string> *cache;
1248         if (client->http_11) {
1249                 if (client->close_after_response) {
1250                         cache = &stream->hls_playlist_http11_close;
1251                 } else {
1252                         cache = &stream->hls_playlist_http11_persistent;
1253                 }
1254         } else {
1255                 assert(client->close_after_response);
1256                 cache = &stream->hls_playlist_http10;
1257         }
1258
1259         if (*cache == nullptr) {
1260                 *cache = stream->generate_hls_playlist(client->http_11, client->close_after_response);
1261         }
1262         client->header_or_short_response_ref = *cache;
1263         client->header_or_short_response = cache->get();
1264
1265         // Switch states.
1266         client->state = Client::SENDING_SHORT_RESPONSE;
1267         change_epoll_events(client, EPOLLOUT | EPOLLET | EPOLLRDHUP);
1268 }
1269
1270 void Server::construct_204(Client *client)
1271 {
1272         const auto ping_url_map_it = ping_url_map.find(client->url);
1273         assert(ping_url_map_it != ping_url_map.end());
1274
1275         string response;
1276         if (client->http_11) {
1277                 response = "HTTP/1.1 204 No Content\r\n";
1278                 if (client->close_after_response) {
1279                         response.append("Connection: close\r\n");
1280                 }
1281         } else {
1282                 response = "HTTP/1.0 204 No Content\r\n";
1283                 assert(client->close_after_response);
1284         }
1285         if (!ping_url_map_it->second.empty()) {
1286                 response.append("Access-Control-Allow-Origin: ");
1287                 response.append(ping_url_map_it->second);
1288                 response.append("\r\n");
1289         }
1290         response.append("\r\n");
1291
1292         client->header_or_short_response_holder = move(response);
1293         client->header_or_short_response = &client->header_or_short_response_holder;
1294
1295         // Switch states.
1296         client->state = Client::SENDING_SHORT_RESPONSE;
1297         change_epoll_events(client, EPOLLOUT | EPOLLET | EPOLLRDHUP);
1298 }
1299
1300 namespace {
1301
1302 template<class T>
1303 void delete_from(vector<T> *v, T elem)
1304 {
1305         typename vector<T>::iterator new_end = remove(v->begin(), v->end(), elem);
1306         v->erase(new_end, v->end());
1307 }
1308
1309 void send_ktls_close(int sock)
1310 {
1311         uint8_t record_type = 21;  // Alert.
1312         uint8_t body[] = {
1313                 1,   // Warning level (but still fatal!).
1314                 0,   // close_notify.
1315         };
1316
1317         int cmsg_len = sizeof(record_type);
1318         char buf[CMSG_SPACE(cmsg_len)];
1319
1320         msghdr msg = {0};
1321         msg.msg_control = buf;
1322         msg.msg_controllen = sizeof(buf);
1323         cmsghdr *cmsg = CMSG_FIRSTHDR(&msg);
1324         cmsg->cmsg_level = SOL_TLS;
1325         cmsg->cmsg_type = TLS_SET_RECORD_TYPE;
1326         cmsg->cmsg_len = CMSG_LEN(cmsg_len);
1327         *CMSG_DATA(cmsg) = record_type;
1328         msg.msg_controllen = cmsg->cmsg_len;
1329
1330         iovec msg_iov;
1331         msg_iov.iov_base = body;
1332         msg_iov.iov_len = sizeof(body);
1333         msg.msg_iov = &msg_iov;
1334         msg.msg_iovlen = 1;
1335
1336         int err;
1337         do {
1338                 err = sendmsg(sock, &msg, 0);
1339         } while (err == -1 && errno == EINTR);  // Ignore all other errors.
1340 }
1341
1342 }  // namespace
1343
1344 void Server::close_client(Client *client)
1345 {
1346         if (epoll_ctl(epoll_fd, EPOLL_CTL_DEL, client->sock, nullptr) == -1) {
1347                 log_perror("epoll_ctl(EPOLL_CTL_DEL)");
1348                 exit(1);
1349         }
1350
1351         // This client could be sleeping, so we'll need to fix that. (Argh, O(n).)
1352         if (client->stream != nullptr) {
1353                 delete_from(&client->stream->sleeping_clients, client);
1354                 delete_from(&client->stream->to_process, client);
1355         }
1356
1357         if (client->tls_context) {
1358                 if (client->in_ktls_mode) {
1359                         // Keep GnuTLS happy.
1360                         send_ktls_close(client->sock);
1361                 }
1362                 tls_destroy_context(client->tls_context);
1363         }
1364
1365         // Log to access_log.
1366         access_log->write(client->get_stats());
1367
1368         // Bye-bye!
1369         safe_close(client->sock);
1370
1371         clients.erase(client->sock);
1372 }
1373
1374 void Server::change_epoll_events(Client *client, uint32_t events)
1375 {
1376         epoll_event ev;
1377         ev.events = events;
1378         ev.data.ptr = client;
1379
1380         if (epoll_ctl(epoll_fd, EPOLL_CTL_MOD, client->sock, &ev) == -1) {
1381                 log_perror("epoll_ctl(EPOLL_CTL_MOD)");
1382                 exit(1);
1383         }
1384 }
1385
1386 bool Server::more_requests(Client *client)
1387 {
1388         if (client->close_after_response) {
1389                 return false;
1390         }
1391
1392         // Log to access_log.
1393         access_log->write(client->get_stats());
1394
1395         flush_pending_data(client->sock);
1396
1397         // Switch states and reset the parsers. We don't reset statistics.
1398         client->state = Client::READING_REQUEST;
1399         client->url.clear();
1400         client->stream = NULL;
1401         client->header_or_short_response = nullptr;
1402         client->header_or_short_response_holder.clear();
1403         client->header_or_short_response_ref.reset();
1404         client->header_or_short_response_bytes_sent = 0;
1405         client->bytes_sent = 0;
1406         start_client_timeout_timer(client);
1407
1408         change_epoll_events(client, EPOLLIN | EPOLLET | EPOLLRDHUP);  // No TLS handshake, so no EPOLLOUT needed.
1409
1410         return true;
1411 }
1412
1413 void Server::process_queued_data()
1414 {
1415         {
1416                 lock_guard<mutex> lock(queued_clients_mutex);
1417
1418                 for (const pair<int, Acceptor *> &id_and_acceptor : queued_add_clients) {
1419                         add_client(id_and_acceptor.first, id_and_acceptor.second);
1420                 }
1421                 queued_add_clients.clear();
1422         }
1423
1424         for (unique_ptr<Stream> &stream : streams) {
1425                 stream->process_queued_data();
1426         }
1427 }