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 < streams[stream_index]->backlog_size);
 439         streams[stream_index]->hls_backlog_margin = hls_backlog_margin;
 440 }
 441
 442 void Server::set_allow_origin(int stream_index, const string &allow_origin)
 443 {
 444         lock_guard<mutex> lock(mu);
 445         assert(stream_index >= 0 && stream_index < ssize_t(streams.size()));
 446         streams[stream_index]->allow_origin = allow_origin;
 447 }
 448
 449 void Server::register_hls_url(int stream_index, const string &hls_url)
 450 {
 451         lock_guard<mutex> lock(mu);
 452         assert(stream_index >= 0 && stream_index < ssize_t(streams.size()));
 453         assert(!hls_url.empty());
 454         stream_hls_url_map.insert(make_pair(hls_url, stream_index));
 455 }
 456
 457 void Server::set_header(int stream_index, const string &http_header, const string &stream_header)
 458 {
 459         lock_guard<mutex> lock(mu);
 460         assert(stream_index >= 0 && stream_index < ssize_t(streams.size()));
 461         streams[stream_index]->set_header(http_header, stream_header);
 462 }
 463
 464 void Server::set_unavailable(int stream_index)
 465 {
 466         lock_guard<mutex> lock(mu);
 467         assert(stream_index >= 0 && stream_index < ssize_t(streams.size()));
 468         streams[stream_index]->set_unavailable();
 469 }
 470
 471 void Server::set_pacing_rate(int stream_index, uint32_t pacing_rate)
 472 {
 473         lock_guard<mutex> lock(mu);
 474         assert(clients.empty());
 475         assert(stream_index >= 0 && stream_index < ssize_t(streams.size()));
 476         streams[stream_index]->pacing_rate = pacing_rate;
 477 }
 478
 479 void Server::add_gen204(const std::string &url, const std::string &allow_origin)
 480 {
 481         lock_guard<mutex> lock(mu);
 482         assert(clients.empty());
 483         ping_url_map[url] = allow_origin;
 484 }
 485
 486 void Server::create_tls_context_for_acceptor(const Acceptor *acceptor)
 487 {
 488         assert(acceptor->is_tls());
 489
 490         bool is_server = true;
 491         TLSContext *server_context = tls_create_context(is_server, TLS_V12);
 492
 493         const string &cert = acceptor->get_certificate_chain();
 494         int num_cert = tls_load_certificates(server_context, reinterpret_cast<const unsigned char *>(cert.data()), cert.size());
 495         assert(num_cert > 0);  // Should have been checked by config earlier.
 496
 497         const string &key = acceptor->get_private_key();
 498         int num_key = tls_load_private_key(server_context, reinterpret_cast<const unsigned char *>(key.data()), key.size());
 499         assert(num_key > 0);  // Should have been checked by config earlier.
 500
 501         tls_server_contexts.insert(make_pair(acceptor, server_context));
 502 }
 503
 504 void Server::add_data_deferred(int stream_index, const char *data, size_t bytes, uint16_t metacube_flags, const RationalPTS &pts)
 505 {
 506         assert(stream_index >= 0 && stream_index < ssize_t(streams.size()));
 507         streams[stream_index]->add_data_deferred(data, bytes, metacube_flags, pts);
 508 }
 509
 510 // See the .h file for postconditions after this function.
 511 void Server::process_client(Client *client)
 512 {
 513         switch (client->state) {
 514         case Client::READING_REQUEST: {
 515                 if (client->tls_context != nullptr && !client->in_ktls_mode) {
 516                         if (send_pending_tls_data(client)) {
 517                                 // send_pending_tls_data() hit postconditions #1 or #4.
 518                                 return;
 519                         }
 520                 }
 521
 522 read_request_again:
 523                 // Try to read more of the request.
 524                 char buf[1024];
 525                 int ret;
 526                 if (client->tls_context == nullptr || client->in_ktls_mode) {
 527                         ret = read_plain_data(client, buf, sizeof(buf));
 528                         if (ret == -1) {
 529                                 // read_plain_data() hit postconditions #1 or #2.
 530                                 return;
 531                         }
 532                 } else {
 533                         ret = read_tls_data(client, buf, sizeof(buf));
 534                         if (ret == -1) {
 535                                 // read_tls_data() hit postconditions #1, #2 or #4.
 536                                 return;
 537                         }
 538                 }
 539
 540                 RequestParseStatus status = wait_for_double_newline(&client->request, buf, ret);
 541
 542                 switch (status) {
 543                 case RP_OUT_OF_SPACE:
 544                         log(WARNING, "[%s] Client sent overlong request!", client->remote_addr.c_str());
 545                         close_client(client);
 546                         return;
 547                 case RP_NOT_FINISHED_YET:
 548                         // OK, we don't have the entire header yet. Fine; we'll get it later.
 549                         // See if there's more data for us.
 550                         goto read_request_again;
 551                 case RP_EXTRA_DATA:
 552                         log(WARNING, "[%s] Junk data after request!", client->remote_addr.c_str());
 553                         close_client(client);
 554                         return;
 555                 case RP_FINISHED:
 556                         break;
 557                 }
 558
 559                 assert(status == RP_FINISHED);
 560
 561                 int error_code = parse_request(client);
 562                 if (error_code == 200) {
 563                         if (client->serving_hls_playlist) {
 564                                 construct_hls_playlist(client);
 565                         } else {
 566                                 construct_stream_header(client);
 567                         }
 568                 } else if (error_code == 204) {
 569                         construct_204(client);
 570                 } else {
 571                         construct_error(client, error_code);
 572                 }
 573
 574                 // We've changed states, so fall through.
 575                 assert(client->state == Client::SENDING_SHORT_RESPONSE ||
 576                        client->state == Client::SENDING_HEADER);
 577         }
 578         case Client::SENDING_SHORT_RESPONSE:
 579         case Client::SENDING_HEADER: {
 580 sending_header_or_short_response_again:
 581                 int ret;
 582                 do {
 583                         ret = write(client->sock,
 584                                     client->header_or_short_response->data() + client->header_or_short_response_bytes_sent,
 585                                     client->header_or_short_response->size() - client->header_or_short_response_bytes_sent);
 586                 } while (ret == -1 && errno == EINTR);
 587
 588                 if (ret == -1 && errno == EAGAIN) {
 589                         // We're out of socket space, so now we're at the “low edge” of epoll's
 590                         // edge triggering. epoll will tell us when there is more room, so for now,
 591                         // just return.
 592                         // This is postcondition #4.
 593                         return;
 594                 }
 595
 596                 if (ret == -1) {
 597                         // Error! Postcondition #1.
 598                         log_perror("write");
 599                         close_client(client);
 600                         return;
 601                 }
 602
 603                 client->header_or_short_response_bytes_sent += ret;
 604                 assert(client->header_or_short_response_bytes_sent <= client->header_or_short_response->size());
 605
 606                 if (client->header_or_short_response_bytes_sent < client->header_or_short_response->size()) {
 607                         // We haven't sent all yet. Fine; go another round.
 608                         goto sending_header_or_short_response_again;
 609                 }
 610
 611                 // We're done sending the header or error! Clear it to release some memory.
 612                 client->header_or_short_response = nullptr;
 613                 client->header_or_short_response_holder.clear();
 614                 client->header_or_short_response_ref.reset();
 615
 616                 if (client->state == Client::SENDING_SHORT_RESPONSE) {
 617                         if (more_requests(client)) {
 618                                 // We're done sending the error, but should keep on reading new requests.
 619                                 goto read_request_again;
 620                         } else {
 621                                 // We're done sending the error, so now close.
 622                                 // This is postcondition #1.
 623                                 close_client(client);
 624                         }
 625                         return;
 626                 }
 627
 628                 Stream *stream = client->stream;
 629                 hls_zombies.erase(client->get_hls_zombie_key());
 630                 if (client->stream_pos == Client::STREAM_POS_AT_START) {
 631                         // Start sending from the beginning of the backlog.
 632                         client->stream_pos = min<size_t>(
 633                             stream->bytes_received - stream->backlog_size,
 634                             0);
 635                         client->state = Client::SENDING_DATA;
 636                         goto sending_data;
 637                 } else if (client->stream_pos_end != Client::STREAM_POS_NO_END) {
 638                         // We're sending a fragment, and should have all of it,
 639                         // so start sending right away.
 640                         assert(ssize_t(client->stream_pos) >= 0);
 641                         client->state = Client::SENDING_DATA;
 642                         goto sending_data;
 643                 } else if (stream->prebuffering_bytes == 0) {
 644                         // Start sending from the first keyframe we get. In other
 645                         // words, we won't send any of the backlog, but we'll start
 646                         // sending immediately as we get the next keyframe block.
 647                         // Note that this is functionally identical to the next if branch,
 648                         // except that we save a binary search.
 649                         assert(client->stream_pos == Client::STREAM_POS_AT_END);
 650                         assert(client->stream_pos_end == Client::STREAM_POS_NO_END);
 651                         client->stream_pos = stream->bytes_received;
 652                         client->state = Client::WAITING_FOR_KEYFRAME;
 653                 } else {
 654                         // We're not going to send anything to the client before we have
 655                         // N bytes. However, this wait might be boring; we can just as well
 656                         // use it to send older data if we have it. We use lower_bound()
 657                         // so that we are conservative and never add extra latency over just
 658                         // waiting (assuming CBR or nearly so); otherwise, we could want e.g.
 659                         // 100 kB prebuffer but end up sending a 10 MB GOP.
 660                         assert(client->stream_pos == Client::STREAM_POS_AT_END);
 661                         assert(client->stream_pos_end == Client::STREAM_POS_NO_END);
 662                         deque<uint64_t>::const_iterator starting_point_it =
 663                                 lower_bound(stream->suitable_starting_points.begin(),
 664                                             stream->suitable_starting_points.end(),
 665                                             stream->bytes_received - stream->prebuffering_bytes);
 666                         if (starting_point_it == stream->suitable_starting_points.end()) {
 667                                 // None found. Just put us at the end, and then wait for the
 668                                 // first keyframe to appear.
 669                                 client->stream_pos = stream->bytes_received;
 670                                 client->state = Client::WAITING_FOR_KEYFRAME;
 671                         } else {
 672                                 client->stream_pos = *starting_point_it;
 673                                 client->state = Client::PREBUFFERING;
 674                                 goto prebuffering;
 675                         }
 676                 }
 677                 // Fall through.
 678         }
 679         case Client::WAITING_FOR_KEYFRAME: {
 680                 Stream *stream = client->stream;
 681                 if (stream->suitable_starting_points.empty() ||
 682                     client->stream_pos > stream->suitable_starting_points.back()) {
 683                         // We haven't received a keyframe since this stream started waiting,
 684                         // so keep on waiting for one.
 685                         // This is postcondition #3.
 686                         stream->put_client_to_sleep(client);
 687                         return;
 688                 }
 689                 client->stream_pos = stream->suitable_starting_points.back();
 690                 client->state = Client::PREBUFFERING;
 691                 // Fall through.
 692         }
 693         case Client::PREBUFFERING: {
 694 prebuffering:
 695                 Stream *stream = client->stream;
 696                 size_t bytes_to_send = stream->bytes_received - client->stream_pos;
 697                 assert(bytes_to_send <= stream->backlog_size);
 698                 if (bytes_to_send < stream->prebuffering_bytes) {
 699                         // We don't have enough bytes buffered to start this client yet.
 700                         // This is postcondition #3.
 701                         stream->put_client_to_sleep(client);
 702                         return;
 703                 }
 704                 client->state = Client::SENDING_DATA;
 705                 // Fall through.
 706         }
 707         case Client::SENDING_DATA: {
 708 sending_data:
 709                 skip_lost_data(client);
 710                 Stream *stream = client->stream;
 711
 712 sending_data_again:
 713                 size_t bytes_to_send;
 714                 if (client->stream_pos_end == Client::STREAM_POS_NO_END) {
 715                          bytes_to_send = stream->bytes_received - client->stream_pos;
 716                 } else {
 717                          bytes_to_send = client->stream_pos_end - client->stream_pos;
 718                 }
 719                 assert(bytes_to_send <= stream->backlog_size);
 720                 if (bytes_to_send == 0) {
 721                         if (client->stream_pos == client->stream_pos_end) {  // We have a definite end, and we're at it.
 722                                 // Add (or overwrite) a HLS zombie.
 723                                 timespec now;
 724                                 if (clock_gettime(CLOCK_MONOTONIC_COARSE, &now) == -1) {
 725                                         log_perror("clock_gettime(CLOCK_MONOTONIC_COARSE)");
 726                                 } else {
 727                                         HLSZombie zombie;
 728                                         zombie.remote_addr = client->remote_addr;
 729                                         zombie.referer = client->referer;
 730                                         zombie.user_agent = client->user_agent;
 731                                         zombie.url = client->stream->url + "?frag=<idle>";
 732                                         zombie.expires = now;
 733                                         zombie.expires.tv_sec += client->stream->hls_frag_duration * 3;
 734                                         hls_zombies[client->get_hls_zombie_key()] = move(zombie);
 735                                 }
 736                                 if (more_requests(client)) {
 737                                         // We're done sending the fragment, but should keep on reading new requests.
 738                                         goto read_request_again;
 739                                 } else {
 740                                         // We're done sending the fragment, so now close.
 741                                         // This is postcondition #1.
 742                                         close_client(client);
 743                                 }
 744                         }
 745                         return;
 746                 }
 747
 748                 // See if we need to split across the circular buffer.
 749                 bool more_data = false;
 750                 if ((client->stream_pos % stream->backlog_size) + bytes_to_send > stream->backlog_size) {
 751                         bytes_to_send = stream->backlog_size - (client->stream_pos % stream->backlog_size);
 752                         more_data = true;
 753                 }
 754
 755                 ssize_t ret;
 756                 do {
 757                         off_t offset = client->stream_pos % stream->backlog_size;
 758                         ret = sendfile(client->sock, stream->data_fd, &offset, bytes_to_send);
 759                 } while (ret == -1 && errno == EINTR);
 760
 761                 if (ret == -1 && errno == EAGAIN) {
 762                         // We're out of socket space, so return; epoll will wake us up
 763                         // when there is more room.
 764                         // This is postcondition #4.
 765                         return;
 766                 }
 767                 if (ret == -1) {
 768                         // Error, close; postcondition #1.
 769                         log_perror("sendfile");
 770                         close_client(client);
 771                         return;
 772                 }
 773                 client->stream_pos += ret;
 774                 client->bytes_sent += ret;
 775
 776                 assert(client->stream_pos_end == Client::STREAM_POS_NO_END || client->stream_pos <= client->stream_pos_end);
 777                 if (client->stream_pos == client->stream_pos_end) {
 778                         goto sending_data_again;  // Will see that bytes_to_send == 0 and end.
 779                 } else if (client->stream_pos == stream->bytes_received) {
 780                         // We don't have any more data for this client, so put it to sleep.
 781                         // This is postcondition #3.
 782                         stream->put_client_to_sleep(client);
 783                 } else if (more_data && size_t(ret) == bytes_to_send) {
 784                         goto sending_data_again;
 785                 }
 786                 // We'll also get here for postcondition #4 (similar to the EAGAIN path above).
 787                 break;
 788         }
 789         default:
 790                 assert(false);
 791         }
 792 }
 793
 794 namespace {
 795
 796 void flush_pending_data(int sock)
 797 {
 798         // Flush pending data, which would otherwise wait for the 200ms TCP_CORK timer
 799         // to elapsed; does not cancel out TCP_CORK (since that still takes priority),
 800         // but does a one-off flush.
 801         int one = 1;
 802         if (setsockopt(sock, SOL_TCP, TCP_NODELAY, &one, sizeof(one)) == -1) {
 803                 log_perror("setsockopt(TCP_NODELAY)");
 804                 // Can still continue.
 805         }
 806 }
 807
 808 }  // namespace
 809
 810 bool Server::send_pending_tls_data(Client *client)
 811 {
 812         // See if there's data from the TLS library to write.
 813         if (client->tls_data_to_send == nullptr) {
 814                 client->tls_data_to_send = tls_get_write_buffer(client->tls_context, &client->tls_data_left_to_send);
 815                 if (client->tls_data_to_send == nullptr) {
 816                         // Really no data to send.
 817                         return false;
 818                 }
 819         }
 820
 821 send_data_again:
 822         int ret;
 823         do {
 824                 ret = write(client->sock, client->tls_data_to_send, client->tls_data_left_to_send);
 825         } while (ret == -1 && errno == EINTR);
 826         assert(ret < 0 || size_t(ret) <= client->tls_data_left_to_send);
 827
 828         if (ret == -1 && errno == EAGAIN) {
 829                 // We're out of socket space, so now we're at the “low edge” of epoll's
 830                 // edge triggering. epoll will tell us when there is more room, so for now,
 831                 // just return.
 832                 // This is postcondition #4.
 833                 return true;
 834         }
 835         if (ret == -1) {
 836                 // Error! Postcondition #1.
 837                 log_perror("write");
 838                 close_client(client);
 839                 return true;
 840         }
 841         if (ret > 0 && size_t(ret) == client->tls_data_left_to_send) {
 842                 // All data has been sent, so we don't need to go to sleep
 843                 // (although we are likely to do so immediately afterwards,
 844                 // due to lack of client data).
 845                 tls_buffer_clear(client->tls_context);
 846                 client->tls_data_to_send = nullptr;
 847
 848                 // Flush the data we just wrote, since the client probably
 849                 // is waiting for it.
 850                 flush_pending_data(client->sock);
 851                 return false;
 852         }
 853
 854         // More data to send, so try again.
 855         client->tls_data_to_send += ret;
 856         client->tls_data_left_to_send -= ret;
 857         goto send_data_again;
 858 }
 859
 860 int Server::read_plain_data(Client *client, char *buf, size_t max_size)
 861 {
 862         int ret;
 863         do {
 864                 ret = read(client->sock, buf, max_size);
 865         } while (ret == -1 && errno == EINTR);
 866
 867         if (ret == -1 && errno == EAGAIN) {
 868                 // No more data right now. Nothing to do.
 869                 // This is postcondition #2.
 870                 return -1;
 871         }
 872         if (ret == -1) {
 873                 log_perror("read");
 874                 close_client(client);
 875                 return -1;
 876         }
 877         if (ret == 0) {
 878                 // OK, the socket is closed.
 879                 close_client(client);
 880                 return -1;
 881         }
 882
 883         return ret;
 884 }
 885
 886 int Server::read_tls_data(Client *client, char *buf, size_t max_size)
 887 {
 888 read_again:
 889         assert(!client->in_ktls_mode);
 890
 891         int ret;
 892         do {
 893                 ret = read(client->sock, buf, max_size);
 894         } while (ret == -1 && errno == EINTR);
 895
 896         if (ret == -1 && errno == EAGAIN) {
 897                 // No more data right now. Nothing to do.
 898                 // This is postcondition #2.
 899                 return -1;
 900         }
 901         if (ret == -1) {
 902                 log_perror("read");
 903                 close_client(client);
 904                 return -1;
 905         }
 906         if (ret == 0) {
 907                 // OK, the socket is closed.
 908                 close_client(client);
 909                 return -1;
 910         }
 911
 912         // Give it to the TLS library.
 913         int err = tls_consume_stream(client->tls_context, reinterpret_cast<const unsigned char *>(buf), ret, nullptr);
 914         if (err < 0) {
 915                 log_tls_error("tls_consume_stream", err);
 916                 close_client(client);
 917                 return -1;
 918         }
 919         if (err == 0) {
 920                 // Not consumed any data. See if we can read more.
 921                 goto read_again;
 922         }
 923
 924         // Read any decrypted data available for us. (We can reuse buf, since it's free now.)
 925         ret = tls_read(client->tls_context, reinterpret_cast<unsigned char *>(buf), max_size);
 926         if (ret == 0) {
 927                 // No decrypted data for us yet, but there might be some more handshaking
 928                 // to send. Do that if needed, then look for more data.
 929                 if (send_pending_tls_data(client)) {
 930                         // send_pending_tls_data() hit postconditions #1 or #4.
 931                         return -1;
 932                 }
 933                 goto read_again;
 934         }
 935         if (ret < 0) {
 936                 log_tls_error("tls_read", ret);
 937                 close_client(client);
 938                 return -1;
 939         }
 940
 941         if (tls_established(client->tls_context)) {
 942                 // We're ready to enter kTLS mode, unless we still have some
 943                 // handshake data to send (which then must be sent as non-kTLS).
 944                 if (send_pending_tls_data(client)) {
 945                         // send_pending_tls_data() hit postconditions #1 or #4.
 946                         return -1;
 947                 }
 948                 int err = tls_make_ktls(client->tls_context, client->sock);  // Don't overwrite ret.
 949                 if (err < 0) {
 950                         log_tls_error("tls_make_ktls", ret);
 951                         close_client(client);
 952                         return -1;
 953                 }
 954                 client->in_ktls_mode = true;
 955         }
 956
 957         assert(ret > 0);
 958         return ret;
 959 }
 960
 961 // See if there's some data we've lost. Ideally, we should drop to a block boundary,
 962 // but resync will be the mux's problem.
 963 void Server::skip_lost_data(Client *client)
 964 {
 965         Stream *stream = client->stream;
 966         if (stream == nullptr) {
 967                 return;
 968         }
 969         size_t bytes_to_send = stream->bytes_received - client->stream_pos;
 970         if (bytes_to_send > stream->backlog_size) {
 971                 size_t bytes_lost = bytes_to_send - stream->backlog_size;
 972                 client->bytes_lost += bytes_lost;
 973                 ++client->num_loss_events;
 974                 if (!client->close_after_response) {
 975                         assert(client->stream_pos_end != Client::STREAM_POS_NO_END);
 976
 977                         // We've already sent a Content-Length, so we can't just skip data.
 978                         // Close the connection immediately and hope the other side
 979                         // is able to figure out that there was an error and it needs to skip.
 980                         client->close_after_response = true;
 981                         client->stream_pos = client->stream_pos_end;
 982                 } else {
 983                         client->stream_pos = stream->bytes_received - stream->backlog_size;
 984                 }
 985         }
 986 }
 987
 988 int Server::parse_request(Client *client)
 989 {
 990         vector<string> lines = split_lines(client->request);
 991         client->request.clear();
 992         if (lines.empty()) {
 993                 return 400;  // Bad request (empty).
 994         }
 995
 996         // Parse the headers, for logging purposes.
 997         HTTPHeaderMultimap headers = extract_headers(lines, client->remote_addr);
 998         const auto referer_it = headers.find("Referer");
 999         if (referer_it != headers.end()) {
1000                 client->referer = referer_it->second;
1001         }
1002         const auto user_agent_it = headers.find("User-Agent");
1003         if (user_agent_it != headers.end()) {
1004                 client->user_agent = user_agent_it->second;
1005         }
1006         const auto x_playback_session_id_it = headers.find("X-Playback-Session-Id");
1007         if (x_playback_session_id_it != headers.end()) {
1008                 client->x_playback_session_id = x_playback_session_id_it->second;
1009         } else {
1010                 client->x_playback_session_id.clear();
1011         }
1012
1013         vector<string> request_tokens = split_tokens(lines[0]);
1014         if (request_tokens.size() < 3) {
1015                 return 400;  // Bad request (empty).
1016         }
1017         if (request_tokens[0] != "GET") {
1018                 return 400;  // Should maybe be 405 instead?
1019         }
1020
1021         string url = request_tokens[1];
1022         client->url = url;
1023         if (url.size() > 8 && url.find("?backlog") == url.size() - 8) {
1024                 client->stream_pos = Client::STREAM_POS_AT_START;
1025                 url = url.substr(0, url.size() - 8);
1026         } else {
1027                 size_t pos = url.find("?frag=");
1028                 if (pos != string::npos) {
1029                         // Parse an endpoint of the type /stream.mp4?frag=1234-5678.
1030                         const char *ptr = url.c_str() + pos + 6;
1031
1032                         // "?frag=header" is special.
1033                         if (strcmp(ptr, "header") == 0) {
1034                                 client->stream_pos = Client::STREAM_POS_HEADER_ONLY;
1035                                 client->stream_pos_end = -1;
1036                         } else {
1037                                 char *endptr;
1038                                 long long frag_start = strtol(ptr, &endptr, 10);
1039                                 if (ptr == endptr || frag_start < 0 || frag_start == LLONG_MAX) {
1040                                         return 400;  // Bad request.
1041                                 }
1042                                 if (*endptr != '-') {
1043                                         return 400;  // Bad request.
1044                                 }
1045                                 ptr = endptr + 1;
1046
1047                                 long long frag_end = strtol(ptr, &endptr, 10);
1048                                 if (ptr == endptr || frag_end < frag_start || frag_end == LLONG_MAX) {
1049                                         return 400;  // Bad request.
1050                                 }
1051
1052                                 if (*endptr != '\0') {
1053                                         return 400;  // Bad request.
1054                                 }
1055
1056                                 client->stream_pos = frag_start;
1057                                 client->stream_pos_end = frag_end;
1058                         }
1059                         url = url.substr(0, pos);
1060                 } else {
1061                         client->stream_pos = -1;
1062                         client->stream_pos_end = -1;
1063                 }
1064         }
1065
1066         // Figure out if we're supposed to close the socket after we've delivered the response.
1067         string protocol = request_tokens[2];
1068         if (protocol.find("HTTP/") != 0) {
1069                 return 400;  // Bad request.
1070         }
1071         client->close_after_response = false;
1072         client->http_11 = true;
1073         if (protocol == "HTTP/1.0") {
1074                 // No persistent connections.
1075                 client->close_after_response = true;
1076                 client->http_11 = false;
1077         } else {
1078                 const auto connection_it = headers.find("Connection");
1079                 if (connection_it != headers.end() && connection_it->second == "close") {
1080                         client->close_after_response = true;
1081                 }
1082         }
1083
1084         const auto stream_url_map_it = stream_url_map.find(url);
1085         if (stream_url_map_it != stream_url_map.end()) {
1086                 // Serve a regular stream..
1087                 client->stream = streams[stream_url_map_it->second].get();
1088                 client->serving_hls_playlist = false;
1089         } else {
1090                 const auto stream_hls_url_map_it = stream_hls_url_map.find(url);
1091                 if (stream_hls_url_map_it != stream_hls_url_map.end()) {
1092                         // Serve HLS playlist.
1093                         client->stream = streams[stream_hls_url_map_it->second].get();
1094                         client->serving_hls_playlist = true;
1095                 } else {
1096                         const auto ping_url_map_it = ping_url_map.find(url);
1097                         if (ping_url_map_it == ping_url_map.end()) {
1098                                 return 404;  // Not found.
1099                         } else {
1100                                 // Serve a ping (204 no error).
1101                                 return 204;
1102                         }
1103                 }
1104         }
1105
1106         Stream *stream = client->stream;
1107
1108         if (client->serving_hls_playlist) {
1109                 if (stream->encoding == Stream::STREAM_ENCODING_METACUBE) {
1110                         // This doesn't make any sense, and is hard to implement, too.
1111                         return 404;
1112                 } else {
1113                         return 200;
1114                 }
1115         }
1116
1117         if (client->stream_pos_end == Client::STREAM_POS_NO_END) {
1118                 if (stream->unavailable) {
1119                         return 503;  // Service unavailable.
1120                 }
1121
1122                 // This stream won't end, so we don't have a content-length,
1123                 // and can just as well tell the client it's Connection: close
1124                 // (otherwise, we'd have to implement chunking TE for no good reason).
1125                 client->close_after_response = true;
1126         } else {
1127                 if (stream->encoding == Stream::STREAM_ENCODING_METACUBE) {
1128                         // This doesn't make any sense, and is hard to implement, too.
1129                         return 416;  // Range not satisfiable.
1130                 }
1131
1132                 // Check that we have the requested fragment in our backlog.
1133                 size_t buffer_end = stream->bytes_received;
1134                 size_t buffer_start = (buffer_end <= stream->backlog_size) ? 0 : buffer_end - stream->backlog_size;
1135
1136                 if (client->stream_pos_end > buffer_end ||
1137                     client->stream_pos < buffer_start) {
1138                         return 416;  // Range not satisfiable.
1139                 }
1140         }
1141
1142         client->stream = stream;
1143         if (setsockopt(client->sock, SOL_SOCKET, SO_MAX_PACING_RATE, &client->stream->pacing_rate, sizeof(client->stream->pacing_rate)) == -1) {
1144                 if (client->stream->pacing_rate != ~0U) {
1145                         log_perror("setsockopt(SO_MAX_PACING_RATE)");
1146                 }
1147         }
1148         client->request.clear();
1149
1150         return 200;  // OK!
1151 }
1152
1153 void Server::construct_stream_header(Client *client)
1154 {
1155         Stream *stream = client->stream;
1156         string response = stream->http_header;
1157         if (client->stream_pos == Client::STREAM_POS_HEADER_ONLY) {
1158                 char buf[64];
1159                 snprintf(buf, sizeof(buf), "Content-Length: %zu\r\n", stream->stream_header.size());
1160                 response.append(buf);
1161         } else if (client->stream_pos_end != Client::STREAM_POS_NO_END) {
1162                 char buf[64];
1163                 snprintf(buf, sizeof(buf), "Content-Length: %" PRIu64 "\r\n", client->stream_pos_end - client->stream_pos);
1164                 response.append(buf);
1165         }
1166         if (client->http_11) {
1167                 assert(response.find("HTTP/1.0") == 0);
1168                 response[7] = '1';  // Change to HTTP/1.1.
1169                 if (client->close_after_response) {
1170                         response.append("Connection: close\r\n");
1171                 }
1172         } else {
1173                 assert(client->close_after_response);
1174         }
1175         if (!stream->allow_origin.empty()) {
1176                 response.append("Access-Control-Allow-Origin: ");
1177                 response.append(stream->allow_origin);
1178                 response.append("\r\n");
1179         }
1180         if (stream->encoding == Stream::STREAM_ENCODING_RAW) {
1181                 response.append("\r\n");
1182         } else if (stream->encoding == Stream::STREAM_ENCODING_METACUBE) {
1183                 response.append("Content-Encoding: metacube\r\n\r\n");
1184                 if (!stream->stream_header.empty()) {
1185                         metacube2_block_header hdr;
1186                         memcpy(hdr.sync, METACUBE2_SYNC, sizeof(hdr.sync));
1187                         hdr.size = htonl(stream->stream_header.size());
1188                         hdr.flags = htons(METACUBE_FLAGS_HEADER);
1189                         hdr.csum = htons(metacube2_compute_crc(&hdr));
1190                         response.append(string(reinterpret_cast<char *>(&hdr), sizeof(hdr)));
1191                 }
1192         } else {
1193                 assert(false);
1194         }
1195         if (client->stream_pos == Client::STREAM_POS_HEADER_ONLY) {
1196                 client->state = Client::SENDING_SHORT_RESPONSE;
1197                 response.append(stream->stream_header);
1198         } else {
1199                 client->state = Client::SENDING_HEADER;
1200                 if (client->stream_pos_end == Client::STREAM_POS_NO_END) {  // Fragments don't contain stream headers.
1201                         response.append(stream->stream_header);
1202                 }
1203         }
1204
1205         client->header_or_short_response_holder = move(response);
1206         client->header_or_short_response = &client->header_or_short_response_holder;
1207
1208         // Switch states.
1209         change_epoll_events(client, EPOLLOUT | EPOLLET | EPOLLRDHUP);
1210 }
1211
1212 void Server::construct_error(Client *client, int error_code)
1213 {
1214         char error[256];
1215         if (client->http_11 && client->close_after_response) {
1216                 snprintf(error, sizeof(error),
1217                         "HTTP/1.1 %d Error\r\nContent-Type: text/plain\r\nConnection: close\r\n\r\nSomething went wrong. Sorry.\r\n",
1218                         error_code);
1219         } else {
1220                 snprintf(error, sizeof(error),
1221                         "HTTP/1.%d %d Error\r\nContent-Type: text/plain\r\nContent-Length: 30\r\n\r\nSomething went wrong. Sorry.\r\n",
1222                         client->http_11, error_code);
1223         }
1224         client->header_or_short_response_holder = error;
1225         client->header_or_short_response = &client->header_or_short_response_holder;
1226
1227         // Switch states.
1228         client->state = Client::SENDING_SHORT_RESPONSE;
1229         change_epoll_events(client, EPOLLOUT | EPOLLET | EPOLLRDHUP);
1230 }
1231
1232 void Server::construct_hls_playlist(Client *client)
1233 {
1234         Stream *stream = client->stream;
1235         shared_ptr<const string> *cache;
1236         if (client->http_11) {
1237                 if (client->close_after_response) {
1238                         cache = &stream->hls_playlist_http11_close;
1239                 } else {
1240                         cache = &stream->hls_playlist_http11_persistent;
1241                 }
1242         } else {
1243                 assert(client->close_after_response);
1244                 cache = &stream->hls_playlist_http10;
1245         }
1246
1247         if (*cache == nullptr) {
1248                 *cache = stream->generate_hls_playlist(client->http_11, client->close_after_response);
1249         }
1250         client->header_or_short_response_ref = *cache;
1251         client->header_or_short_response = cache->get();
1252
1253         // Switch states.
1254         client->state = Client::SENDING_SHORT_RESPONSE;
1255         change_epoll_events(client, EPOLLOUT | EPOLLET | EPOLLRDHUP);
1256 }
1257
1258 void Server::construct_204(Client *client)
1259 {
1260         const auto ping_url_map_it = ping_url_map.find(client->url);
1261         assert(ping_url_map_it != ping_url_map.end());
1262
1263         string response;
1264         if (client->http_11) {
1265                 response = "HTTP/1.1 204 No Content\r\n";
1266                 if (client->close_after_response) {
1267                         response.append("Connection: close\r\n");
1268                 }
1269         } else {
1270                 response = "HTTP/1.0 204 No Content\r\n";
1271                 assert(client->close_after_response);
1272         }
1273         if (!ping_url_map_it->second.empty()) {
1274                 response.append("Access-Control-Allow-Origin: ");
1275                 response.append(ping_url_map_it->second);
1276                 response.append("\r\n");
1277         }
1278         response.append("\r\n");
1279
1280         client->header_or_short_response_holder = move(response);
1281         client->header_or_short_response = &client->header_or_short_response_holder;
1282
1283         // Switch states.
1284         client->state = Client::SENDING_SHORT_RESPONSE;
1285         change_epoll_events(client, EPOLLOUT | EPOLLET | EPOLLRDHUP);
1286 }
1287
1288 namespace {
1289
1290 template<class T>
1291 void delete_from(vector<T> *v, T elem)
1292 {
1293         typename vector<T>::iterator new_end = remove(v->begin(), v->end(), elem);
1294         v->erase(new_end, v->end());
1295 }
1296
1297 void send_ktls_close(int sock)
1298 {
1299         uint8_t record_type = 21;  // Alert.
1300         uint8_t body[] = {
1301                 1,   // Warning level (but still fatal!).
1302                 0,   // close_notify.
1303         };
1304
1305         int cmsg_len = sizeof(record_type);
1306         char buf[CMSG_SPACE(cmsg_len)];
1307
1308         msghdr msg = {0};
1309         msg.msg_control = buf;
1310         msg.msg_controllen = sizeof(buf);
1311         cmsghdr *cmsg = CMSG_FIRSTHDR(&msg);
1312         cmsg->cmsg_level = SOL_TLS;
1313         cmsg->cmsg_type = TLS_SET_RECORD_TYPE;
1314         cmsg->cmsg_len = CMSG_LEN(cmsg_len);
1315         *CMSG_DATA(cmsg) = record_type;
1316         msg.msg_controllen = cmsg->cmsg_len;
1317
1318         iovec msg_iov;
1319         msg_iov.iov_base = body;
1320         msg_iov.iov_len = sizeof(body);
1321         msg.msg_iov = &msg_iov;
1322         msg.msg_iovlen = 1;
1323
1324         int err;
1325         do {
1326                 err = sendmsg(sock, &msg, 0);
1327         } while (err == -1 && errno == EINTR);  // Ignore all other errors.
1328 }
1329
1330 }  // namespace
1331
1332 void Server::close_client(Client *client)
1333 {
1334         if (epoll_ctl(epoll_fd, EPOLL_CTL_DEL, client->sock, nullptr) == -1) {
1335                 log_perror("epoll_ctl(EPOLL_CTL_DEL)");
1336                 exit(1);
1337         }
1338
1339         // This client could be sleeping, so we'll need to fix that. (Argh, O(n).)
1340         if (client->stream != nullptr) {
1341                 delete_from(&client->stream->sleeping_clients, client);
1342                 delete_from(&client->stream->to_process, client);
1343         }
1344
1345         if (client->tls_context) {
1346                 if (client->in_ktls_mode) {
1347                         // Keep GnuTLS happy.
1348                         send_ktls_close(client->sock);
1349                 }
1350                 tls_destroy_context(client->tls_context);
1351         }
1352
1353         // Log to access_log.
1354         access_log->write(client->get_stats());
1355
1356         // Bye-bye!
1357         safe_close(client->sock);
1358
1359         clients.erase(client->sock);
1360 }
1361
1362 void Server::change_epoll_events(Client *client, uint32_t events)
1363 {
1364         epoll_event ev;
1365         ev.events = events;
1366         ev.data.ptr = client;
1367
1368         if (epoll_ctl(epoll_fd, EPOLL_CTL_MOD, client->sock, &ev) == -1) {
1369                 log_perror("epoll_ctl(EPOLL_CTL_MOD)");
1370                 exit(1);
1371         }
1372 }
1373
1374 bool Server::more_requests(Client *client)
1375 {
1376         if (client->close_after_response) {
1377                 return false;
1378         }
1379
1380         // Log to access_log.
1381         access_log->write(client->get_stats());
1382
1383         flush_pending_data(client->sock);
1384
1385         // Switch states and reset the parsers. We don't reset statistics.
1386         client->state = Client::READING_REQUEST;
1387         client->url.clear();
1388         client->stream = NULL;
1389         client->header_or_short_response = nullptr;
1390         client->header_or_short_response_holder.clear();
1391         client->header_or_short_response_ref.reset();
1392         client->header_or_short_response_bytes_sent = 0;
1393         client->bytes_sent = 0;
1394         start_client_timeout_timer(client);
1395
1396         change_epoll_events(client, EPOLLIN | EPOLLET | EPOLLRDHUP);  // No TLS handshake, so no EPOLLOUT needed.
1397
1398         return true;
1399 }
1400
1401 void Server::process_queued_data()
1402 {
1403         {
1404                 lock_guard<mutex> lock(queued_clients_mutex);
1405
1406                 for (const pair<int, Acceptor *> &id_and_acceptor : queued_add_clients) {
1407                         add_client(id_and_acceptor.first, id_and_acceptor.second);
1408                 }
1409                 queued_add_clients.clear();
1410         }
1411
1412         for (unique_ptr<Stream> &stream : streams) {
1413                 stream->process_queued_data();
1414         }
1415 }