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

   1 #include <assert.h>
   2 #include <errno.h>
   3 #include <netinet/in.h>
   4 #include <pthread.h>
   5 #include <stdint.h>
   6 #include <stdio.h>
   7 #include <stdlib.h>
   8 #include <string.h>
   9 #include <sys/epoll.h>
  10 #include <sys/sendfile.h>
  11 #include <sys/socket.h>
  12 #include <sys/types.h>
  13 #include <unistd.h>
  14 #include <algorithm>
  15 #include <map>
  16 #include <string>
  17 #include <utility>
  18 #include <vector>
  19
  20 #include "tlse.h"
  21
  22 #include "acceptor.h"
  23 #include "accesslog.h"
  24 #include "log.h"
  25 #include "metacube2.h"
  26 #include "mutexlock.h"
  27 #include "parse.h"
  28 #include "server.h"
  29 #include "state.pb.h"
  30 #include "stream.h"
  31 #include "util.h"
  32
  33 #ifndef SO_MAX_PACING_RATE
  34 #define SO_MAX_PACING_RATE 47
  35 #endif
  36
  37 using namespace std;
  38
  39 extern AccessLogThread *access_log;
  40
  41 namespace {
  42
  43 inline bool is_equal(timespec a, timespec b)
  44 {
  45         return a.tv_sec == b.tv_sec &&
  46                a.tv_nsec == b.tv_nsec;
  47 }
  48
  49 inline bool is_earlier(timespec a, timespec b)
  50 {
  51         if (a.tv_sec != b.tv_sec)
  52                 return a.tv_sec < b.tv_sec;
  53         return a.tv_nsec < b.tv_nsec;
  54 }
  55
  56 }  // namespace
  57
  58 Server::Server()
  59 {
  60         pthread_mutex_init(&mutex, NULL);
  61         pthread_mutex_init(&queued_clients_mutex, NULL);
  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         for (size_t i = 0; i < streams.size(); ++i) {
  73                 delete streams[i];
  74         }
  75
  76         safe_close(epoll_fd);
  77 }
  78
  79 vector<ClientStats> Server::get_client_stats() const
  80 {
  81         vector<ClientStats> ret;
  82
  83         MutexLock lock(&mutex);
  84         for (map<int, Client>::const_iterator client_it = clients.begin();
  85              client_it != clients.end();
  86              ++client_it) {
  87                 ret.push_back(client_it->second.get_stats());
  88         }
  89         return ret;
  90 }
  91
  92 void Server::do_work()
  93 {
  94         while (!should_stop()) {
  95                 // Wait until there's activity on at least one of the fds,
  96                 // or 20 ms (about one frame at 50 fps) has elapsed.
  97                 //
  98                 // We could in theory wait forever and rely on wakeup()
  99                 // from add_client_deferred() and add_data_deferred(),
 100                 // but wakeup is a pretty expensive operation, and the
 101                 // two threads might end up fighting over a lock, so it's
 102                 // seemingly (much) more efficient to just have a timeout here.
 103                 int nfds = epoll_pwait(epoll_fd, events, EPOLL_MAX_EVENTS, EPOLL_TIMEOUT_MS, &sigset_without_usr1_block);
 104                 if (nfds == -1 && errno != EINTR) {
 105                         log_perror("epoll_wait");
 106                         exit(1);
 107                 }
 108
 109                 MutexLock lock(&mutex);  // We release the mutex between iterations.
 110
 111                 process_queued_data();
 112
 113                 // Process each client where we have socket activity.
 114                 for (int i = 0; i < nfds; ++i) {
 115                         Client *client = reinterpret_cast<Client *>(events[i].data.ptr);
 116
 117                         if (events[i].events & (EPOLLERR | EPOLLRDHUP | EPOLLHUP)) {
 118                                 close_client(client);
 119                                 continue;
 120                         }
 121
 122                         process_client(client);
 123                 }
 124
 125                 // Process each client where its stream has new data,
 126                 // even if there was no socket activity.
 127                 for (size_t i = 0; i < streams.size(); ++i) {
 128                         vector<Client *> to_process;
 129                         swap(streams[i]->to_process, to_process);
 130                         for (size_t i = 0; i < to_process.size(); ++i) {
 131                                 process_client(to_process[i]);
 132                         }
 133                 }
 134
 135                 // Finally, go through each client to see if it's timed out
 136                 // in the READING_REQUEST state. (Seemingly there are clients
 137                 // that can hold sockets up for days at a time without sending
 138                 // anything at all.)
 139                 timespec timeout_time;
 140                 if (clock_gettime(CLOCK_MONOTONIC_COARSE, &timeout_time) == -1) {
 141                         log_perror("clock_gettime(CLOCK_MONOTONIC_COARSE)");
 142                         continue;
 143                 }
 144                 timeout_time.tv_sec -= REQUEST_READ_TIMEOUT_SEC;
 145                 while (!clients_ordered_by_connect_time.empty()) {
 146                         const pair<timespec, int> &connect_time_and_fd = clients_ordered_by_connect_time.front();
 147
 148                         // See if we have reached the end of clients to process.
 149                         if (is_earlier(timeout_time, connect_time_and_fd.first)) {
 150                                 break;
 151                         }
 152
 153                         // If this client doesn't exist anymore, just ignore it
 154                         // (it was deleted earlier).
 155                         map<int, Client>::iterator client_it = clients.find(connect_time_and_fd.second);
 156                         if (client_it == clients.end()) {
 157                                 clients_ordered_by_connect_time.pop();
 158                                 continue;
 159                         }
 160                         Client *client = &client_it->second;
 161                         if (!is_equal(client->connect_time, connect_time_and_fd.first)) {
 162                                 // Another client has taken this fd in the meantime.
 163                                 clients_ordered_by_connect_time.pop();
 164                                 continue;
 165                         }
 166
 167                         if (client->state != Client::READING_REQUEST) {
 168                                 // Only READING_REQUEST can time out.
 169                                 clients_ordered_by_connect_time.pop();
 170                                 continue;
 171                         }
 172
 173                         // OK, it timed out.
 174                         close_client(client);
 175                         clients_ordered_by_connect_time.pop();
 176                 }
 177         }
 178 }
 179
 180 CubemapStateProto Server::serialize()
 181 {
 182         // We don't serialize anything queued, so empty the queues.
 183         process_queued_data();
 184
 185         // Set all clients in a consistent state before serializing
 186         // (ie., they have no remaining lost data). Otherwise, increasing
 187         // the backlog could take clients into a newly valid area of the backlog,
 188         // sending a stream of zeros instead of skipping the data as it should.
 189         //
 190         // TODO: Do this when clients are added back from serialized state instead;
 191         // it would probably be less wasteful.
 192         for (map<int, Client>::iterator client_it = clients.begin();
 193              client_it != clients.end();
 194              ++client_it) {
 195                 skip_lost_data(&client_it->second);
 196         }
 197
 198         CubemapStateProto serialized;
 199         for (map<int, Client>::const_iterator client_it = clients.begin();
 200              client_it != clients.end();
 201              ++client_it) {
 202                 serialized.add_clients()->MergeFrom(client_it->second.serialize());
 203         }
 204         for (size_t i = 0; i < streams.size(); ++i) {
 205                 serialized.add_streams()->MergeFrom(streams[i]->serialize());
 206         }
 207         return serialized;
 208 }
 209
 210 void Server::add_client_deferred(int sock, Acceptor *acceptor)
 211 {
 212         MutexLock lock(&queued_clients_mutex);
 213         queued_add_clients.push_back(std::make_pair(sock, acceptor));
 214 }
 215
 216 void Server::add_client(int sock, Acceptor *acceptor)
 217 {
 218         const bool is_tls = acceptor->is_tls();
 219         pair<map<int, Client>::iterator, bool> ret =
 220                 clients.insert(make_pair(sock, Client(sock)));
 221         assert(ret.second == true);  // Should not already exist.
 222         Client *client_ptr = &ret.first->second;
 223
 224         // Connection timestamps must be nondecreasing. I can't find any guarantee
 225         // that even the monotonic clock can't go backwards by a small amount
 226         // (think switching between CPUs with non-synchronized TSCs), so if
 227         // this actually should happen, we hack around it by fudging
 228         // connect_time.
 229         if (!clients_ordered_by_connect_time.empty() &&
 230             is_earlier(client_ptr->connect_time, clients_ordered_by_connect_time.back().first)) {
 231                 client_ptr->connect_time = clients_ordered_by_connect_time.back().first;
 232         }
 233         clients_ordered_by_connect_time.push(make_pair(client_ptr->connect_time, sock));
 234
 235         // Start listening on data from this socket.
 236         epoll_event ev;
 237         if (is_tls) {
 238                 // Even in the initial state (READING_REQUEST), TLS needs to
 239                 // send data for the handshake, and thus might end up needing
 240                 // to know about EPOLLOUT.
 241                 ev.events = EPOLLIN | EPOLLOUT | EPOLLET | EPOLLRDHUP;
 242         } else {
 243                 // EPOLLOUT will be added once we go out of READING_REQUEST.
 244                 ev.events = EPOLLIN | EPOLLET | EPOLLRDHUP;
 245         }
 246         ev.data.ptr = client_ptr;
 247         if (epoll_ctl(epoll_fd, EPOLL_CTL_ADD, sock, &ev) == -1) {
 248                 log_perror("epoll_ctl(EPOLL_CTL_ADD)");
 249                 exit(1);
 250         }
 251
 252         if (is_tls) {
 253                 assert(tls_server_contexts.count(acceptor));
 254                 client_ptr->tls_context = tls_accept(tls_server_contexts[acceptor]);
 255                 if (client_ptr->tls_context == NULL) {
 256                         log(ERROR, "tls_accept() failed");
 257                         close_client(client_ptr);
 258                         return;
 259                 }
 260                 tls_make_exportable(client_ptr->tls_context, 1);
 261         }
 262
 263         process_client(client_ptr);
 264 }
 265
 266 void Server::add_client_from_serialized(const ClientProto &client)
 267 {
 268         MutexLock lock(&mutex);
 269         Stream *stream;
 270         int stream_index = lookup_stream_by_url(client.url());
 271         if (stream_index == -1) {
 272                 assert(client.state() != Client::SENDING_DATA);
 273                 stream = NULL;
 274         } else {
 275                 stream = streams[stream_index];
 276         }
 277         pair<map<int, Client>::iterator, bool> ret =
 278                 clients.insert(make_pair(client.sock(), Client(client, stream)));
 279         assert(ret.second == true);  // Should not already exist.
 280         Client *client_ptr = &ret.first->second;
 281
 282         // Connection timestamps must be nondecreasing.
 283         assert(clients_ordered_by_connect_time.empty() ||
 284                !is_earlier(client_ptr->connect_time, clients_ordered_by_connect_time.back().first));
 285         clients_ordered_by_connect_time.push(make_pair(client_ptr->connect_time, client.sock()));
 286
 287         // Start listening on data from this socket.
 288         epoll_event ev;
 289         if (client.state() == Client::READING_REQUEST) {
 290                 // See the corresponding comment in Server::add_client().
 291                 if (client.has_tls_context()) {
 292                         ev.events = EPOLLIN | EPOLLOUT | EPOLLET | EPOLLRDHUP;
 293                 } else {
 294                         ev.events = EPOLLIN | EPOLLET | EPOLLRDHUP;
 295                 }
 296         } else {
 297                 // If we don't have more data for this client, we'll be putting it into
 298                 // the sleeping array again soon.
 299                 ev.events = EPOLLOUT | EPOLLET | EPOLLRDHUP;
 300         }
 301         ev.data.ptr = client_ptr;
 302         if (epoll_ctl(epoll_fd, EPOLL_CTL_ADD, client.sock(), &ev) == -1) {
 303                 log_perror("epoll_ctl(EPOLL_CTL_ADD)");
 304                 exit(1);
 305         }
 306
 307         if (client_ptr->state == Client::WAITING_FOR_KEYFRAME ||
 308             client_ptr->state == Client::PREBUFFERING ||
 309             (client_ptr->state == Client::SENDING_DATA &&
 310              client_ptr->stream_pos == client_ptr->stream->bytes_received)) {
 311                 client_ptr->stream->put_client_to_sleep(client_ptr);
 312         } else {
 313                 process_client(client_ptr);
 314         }
 315 }
 316
 317 int Server::lookup_stream_by_url(const string &url) const
 318 {
 319         map<string, int>::const_iterator stream_url_it = stream_url_map.find(url);
 320         if (stream_url_it == stream_url_map.end()) {
 321                 return -1;
 322         }
 323         return stream_url_it->second;
 324 }
 325
 326 int Server::add_stream(const string &url, size_t backlog_size, size_t prebuffering_bytes, Stream::Encoding encoding, Stream::Encoding src_encoding)
 327 {
 328         MutexLock lock(&mutex);
 329         stream_url_map.insert(make_pair(url, streams.size()));
 330         streams.push_back(new Stream(url, backlog_size, prebuffering_bytes, encoding, src_encoding));
 331         return streams.size() - 1;
 332 }
 333
 334 int Server::add_stream_from_serialized(const StreamProto &stream, int data_fd)
 335 {
 336         MutexLock lock(&mutex);
 337         stream_url_map.insert(make_pair(stream.url(), streams.size()));
 338         streams.push_back(new Stream(stream, data_fd));
 339         return streams.size() - 1;
 340 }
 341
 342 void Server::set_backlog_size(int stream_index, size_t new_size)
 343 {
 344         MutexLock lock(&mutex);
 345         assert(stream_index >= 0 && stream_index < ssize_t(streams.size()));
 346         streams[stream_index]->set_backlog_size(new_size);
 347 }
 348
 349 void Server::set_prebuffering_bytes(int stream_index, size_t new_amount)
 350 {
 351         MutexLock lock(&mutex);
 352         assert(stream_index >= 0 && stream_index < ssize_t(streams.size()));
 353         streams[stream_index]->prebuffering_bytes = new_amount;
 354 }
 355
 356 void Server::set_encoding(int stream_index, Stream::Encoding encoding)
 357 {
 358         MutexLock lock(&mutex);
 359         assert(stream_index >= 0 && stream_index < ssize_t(streams.size()));
 360         streams[stream_index]->encoding = encoding;
 361 }
 362
 363 void Server::set_src_encoding(int stream_index, Stream::Encoding encoding)
 364 {
 365         MutexLock lock(&mutex);
 366         assert(stream_index >= 0 && stream_index < ssize_t(streams.size()));
 367         streams[stream_index]->src_encoding = encoding;
 368 }
 369
 370 void Server::set_header(int stream_index, const string &http_header, const string &stream_header)
 371 {
 372         MutexLock lock(&mutex);
 373         assert(stream_index >= 0 && stream_index < ssize_t(streams.size()));
 374         streams[stream_index]->http_header = http_header;
 375
 376         if (stream_header != streams[stream_index]->stream_header) {
 377                 // We cannot start at any of the older starting points anymore,
 378                 // since they'd get the wrong header for the stream (not to mention
 379                 // that a changed header probably means the stream restarted,
 380                 // which means any client starting on the old one would probably
 381                 // stop playing properly at the change point). Next block
 382                 // should be a suitable starting point (if not, something is
 383                 // pretty strange), so it will fill up again soon enough.
 384                 streams[stream_index]->suitable_starting_points.clear();
 385         }
 386         streams[stream_index]->stream_header = stream_header;
 387 }
 388
 389 void Server::set_pacing_rate(int stream_index, uint32_t pacing_rate)
 390 {
 391         MutexLock lock(&mutex);
 392         assert(clients.empty());
 393         assert(stream_index >= 0 && stream_index < ssize_t(streams.size()));
 394         streams[stream_index]->pacing_rate = pacing_rate;
 395 }
 396
 397 void Server::add_gen204(const std::string &url, const std::string &allow_origin)
 398 {
 399         MutexLock lock(&mutex);
 400         assert(clients.empty());
 401         ping_url_map[url] = allow_origin;
 402 }
 403
 404 void Server::create_tls_context_for_acceptor(const Acceptor *acceptor)
 405 {
 406         assert(acceptor->is_tls());
 407
 408         bool is_server = true;
 409         TLSContext *server_context = tls_create_context(is_server, TLS_V12);
 410
 411         const string &cert = acceptor->get_certificate_chain();
 412         int num_cert = tls_load_certificates(server_context, reinterpret_cast<const unsigned char *>(cert.data()), cert.size());
 413         assert(num_cert > 0);  // Should have been checked by config earlier.
 414
 415         const string &key = acceptor->get_private_key();
 416         int num_key = tls_load_private_key(server_context, reinterpret_cast<const unsigned char *>(key.data()), key.size());
 417         assert(num_key > 0);  // Should have been checked by config earlier.
 418
 419         tls_server_contexts.insert(make_pair(acceptor, server_context));
 420 }
 421
 422 void Server::add_data_deferred(int stream_index, const char *data, size_t bytes, uint16_t metacube_flags)
 423 {
 424         assert(stream_index >= 0 && stream_index < ssize_t(streams.size()));
 425         streams[stream_index]->add_data_deferred(data, bytes, metacube_flags);
 426 }
 427
 428 // See the .h file for postconditions after this function.
 429 void Server::process_client(Client *client)
 430 {
 431         switch (client->state) {
 432         case Client::READING_REQUEST: {
 433                 if (client->tls_context != NULL) {
 434                         if (send_pending_tls_data(client)) {
 435                                 // send_pending_tls_data() hit postconditions #1 or #4.
 436                                 return;
 437                         }
 438                 }
 439
 440 read_request_again:
 441                 // Try to read more of the request.
 442                 char buf[1024];
 443                 int ret;
 444                 if (client->tls_context == NULL) {
 445                         ret = read_nontls_data(client, buf, sizeof(buf));
 446                         if (ret == -1) {
 447                                 // read_nontls_data() hit postconditions #1 or #2.
 448                                 return;
 449                         }
 450                 } else {
 451                         ret = read_tls_data(client, buf, sizeof(buf));
 452                         if (ret == -1) {
 453                                 // read_tls_data() hit postconditions #1, #2 or #4.
 454                                 return;
 455                         }
 456                 }
 457
 458                 RequestParseStatus status = wait_for_double_newline(&client->request, buf, ret);
 459
 460                 switch (status) {
 461                 case RP_OUT_OF_SPACE:
 462                         log(WARNING, "[%s] Client sent overlong request!", client->remote_addr.c_str());
 463                         close_client(client);
 464                         return;
 465                 case RP_NOT_FINISHED_YET:
 466                         // OK, we don't have the entire header yet. Fine; we'll get it later.
 467                         // See if there's more data for us.
 468                         goto read_request_again;
 469                 case RP_EXTRA_DATA:
 470                         log(WARNING, "[%s] Junk data after request!", client->remote_addr.c_str());
 471                         close_client(client);
 472                         return;
 473                 case RP_FINISHED:
 474                         break;
 475                 }
 476
 477                 assert(status == RP_FINISHED);
 478
 479                 if (client->tls_context && !client->in_ktls_mode && tls_established(client->tls_context)) {
 480                         // We're ready to enter kTLS mode, unless we still have some
 481                         // handshake data to send (which then must be sent as non-kTLS).
 482                         if (send_pending_tls_data(client)) {
 483                                 // send_pending_tls_data() hit postconditions #1 or #4.
 484                                 return;
 485                         }
 486                         ret = tls_make_ktls(client->tls_context, client->sock);
 487                         if (ret < 0) {
 488                                 log_tls_error("tls_make_ktls", ret);
 489                                 close_client(client);
 490                                 return;
 491                         }
 492                         client->in_ktls_mode = true;
 493                 }
 494
 495                 int error_code = parse_request(client);
 496                 if (error_code == 200) {
 497                         construct_header(client);
 498                 } else if (error_code == 204) {
 499                         construct_204(client);
 500                 } else {
 501                         construct_error(client, error_code);
 502                 }
 503
 504                 // We've changed states, so fall through.
 505                 assert(client->state == Client::SENDING_SHORT_RESPONSE ||
 506                        client->state == Client::SENDING_HEADER);
 507         }
 508         case Client::SENDING_SHORT_RESPONSE:
 509         case Client::SENDING_HEADER: {
 510 sending_header_or_short_response_again:
 511                 int ret;
 512                 do {
 513                         ret = write(client->sock,
 514                                     client->header_or_short_response.data() + client->header_or_short_response_bytes_sent,
 515                                     client->header_or_short_response.size() - client->header_or_short_response_bytes_sent);
 516                 } while (ret == -1 && errno == EINTR);
 517
 518                 if (ret == -1 && errno == EAGAIN) {
 519                         // We're out of socket space, so now we're at the “low edge” of epoll's
 520                         // edge triggering. epoll will tell us when there is more room, so for now,
 521                         // just return.
 522                         // This is postcondition #4.
 523                         return;
 524                 }
 525
 526                 if (ret == -1) {
 527                         // Error! Postcondition #1.
 528                         log_perror("write");
 529                         close_client(client);
 530                         return;
 531                 }
 532
 533                 client->header_or_short_response_bytes_sent += ret;
 534                 assert(client->header_or_short_response_bytes_sent <= client->header_or_short_response.size());
 535
 536                 if (client->header_or_short_response_bytes_sent < client->header_or_short_response.size()) {
 537                         // We haven't sent all yet. Fine; go another round.
 538                         goto sending_header_or_short_response_again;
 539                 }
 540
 541                 // We're done sending the header or error! Clear it to release some memory.
 542                 client->header_or_short_response.clear();
 543
 544                 if (client->state == Client::SENDING_SHORT_RESPONSE) {
 545                         // We're done sending the error, so now close.
 546                         // This is postcondition #1.
 547                         close_client(client);
 548                         return;
 549                 }
 550
 551                 Stream *stream = client->stream;
 552                 if (client->stream_pos == size_t(-2)) {
 553                         // Start sending from the beginning of the backlog.
 554                         client->stream_pos = min<size_t>(
 555                             stream->bytes_received - stream->backlog_size,
 556                             0);
 557                         client->state = Client::SENDING_DATA;
 558                         goto sending_data;
 559                 } else if (stream->prebuffering_bytes == 0) {
 560                         // Start sending from the first keyframe we get. In other
 561                         // words, we won't send any of the backlog, but we'll start
 562                         // sending immediately as we get the next keyframe block.
 563                         // Note that this is functionally identical to the next if branch,
 564                         // except that we save a binary search.
 565                         client->stream_pos = stream->bytes_received;
 566                         client->state = Client::WAITING_FOR_KEYFRAME;
 567                 } else {
 568                         // We're not going to send anything to the client before we have
 569                         // N bytes. However, this wait might be boring; we can just as well
 570                         // use it to send older data if we have it. We use lower_bound()
 571                         // so that we are conservative and never add extra latency over just
 572                         // waiting (assuming CBR or nearly so); otherwise, we could want e.g.
 573                         // 100 kB prebuffer but end up sending a 10 MB GOP.
 574                         deque<size_t>::const_iterator starting_point_it =
 575                                 lower_bound(stream->suitable_starting_points.begin(),
 576                                             stream->suitable_starting_points.end(),
 577                                             stream->bytes_received - stream->prebuffering_bytes);
 578                         if (starting_point_it == stream->suitable_starting_points.end()) {
 579                                 // None found. Just put us at the end, and then wait for the
 580                                 // first keyframe to appear.
 581                                 client->stream_pos = stream->bytes_received;
 582                                 client->state = Client::WAITING_FOR_KEYFRAME;
 583                         } else {
 584                                 client->stream_pos = *starting_point_it;
 585                                 client->state = Client::PREBUFFERING;
 586                                 goto prebuffering;
 587                         }
 588                 }
 589                 // Fall through.
 590         }
 591         case Client::WAITING_FOR_KEYFRAME: {
 592                 Stream *stream = client->stream;
 593                 if (stream->suitable_starting_points.empty() ||
 594                     client->stream_pos > stream->suitable_starting_points.back()) {
 595                         // We haven't received a keyframe since this stream started waiting,
 596                         // so keep on waiting for one.
 597                         // This is postcondition #3.
 598                         stream->put_client_to_sleep(client);
 599                         return;
 600                 }
 601                 client->stream_pos = stream->suitable_starting_points.back();
 602                 client->state = Client::PREBUFFERING;
 603                 // Fall through.
 604         }
 605         case Client::PREBUFFERING: {
 606 prebuffering:
 607                 Stream *stream = client->stream;
 608                 size_t bytes_to_send = stream->bytes_received - client->stream_pos;
 609                 assert(bytes_to_send <= stream->backlog_size);
 610                 if (bytes_to_send < stream->prebuffering_bytes) {
 611                         // We don't have enough bytes buffered to start this client yet.
 612                         // This is postcondition #3.
 613                         stream->put_client_to_sleep(client);
 614                         return;
 615                 }
 616                 client->state = Client::SENDING_DATA;
 617                 // Fall through.
 618         }
 619         case Client::SENDING_DATA: {
 620 sending_data:
 621                 skip_lost_data(client);
 622                 Stream *stream = client->stream;
 623
 624 sending_data_again:
 625                 size_t bytes_to_send = stream->bytes_received - client->stream_pos;
 626                 assert(bytes_to_send <= stream->backlog_size);
 627                 if (bytes_to_send == 0) {
 628                         return;
 629                 }
 630
 631                 // See if we need to split across the circular buffer.
 632                 bool more_data = false;
 633                 if ((client->stream_pos % stream->backlog_size) + bytes_to_send > stream->backlog_size) {
 634                         bytes_to_send = stream->backlog_size - (client->stream_pos % stream->backlog_size);
 635                         more_data = true;
 636                 }
 637
 638                 ssize_t ret;
 639                 do {
 640                         off_t offset = client->stream_pos % stream->backlog_size;
 641                         ret = sendfile(client->sock, stream->data_fd, &offset, bytes_to_send);
 642                 } while (ret == -1 && errno == EINTR);
 643
 644                 if (ret == -1 && errno == EAGAIN) {
 645                         // We're out of socket space, so return; epoll will wake us up
 646                         // when there is more room.
 647                         // This is postcondition #4.
 648                         return;
 649                 }
 650                 if (ret == -1) {
 651                         // Error, close; postcondition #1.
 652                         log_perror("sendfile");
 653                         close_client(client);
 654                         return;
 655                 }
 656                 client->stream_pos += ret;
 657                 client->bytes_sent += ret;
 658
 659                 if (client->stream_pos == stream->bytes_received) {
 660                         // We don't have any more data for this client, so put it to sleep.
 661                         // This is postcondition #3.
 662                         stream->put_client_to_sleep(client);
 663                 } else if (more_data && size_t(ret) == bytes_to_send) {
 664                         goto sending_data_again;
 665                 }
 666                 break;
 667         }
 668         default:
 669                 assert(false);
 670         }
 671 }
 672
 673 bool Server::send_pending_tls_data(Client *client)
 674 {
 675         // See if there's data from the TLS library to write.
 676         if (client->tls_data_to_send == NULL) {
 677                 client->tls_data_to_send = tls_get_write_buffer(client->tls_context, &client->tls_data_left_to_send);
 678                 if (client->tls_data_to_send == NULL) {
 679                         // Really no data to send.
 680                         return false;
 681                 }
 682         }
 683
 684 send_data_again:
 685         int ret;
 686         do {
 687                 ret = write(client->sock, client->tls_data_to_send, client->tls_data_left_to_send);
 688         } while (ret == -1 && errno == EINTR);
 689         assert(ret < 0 || size_t(ret) <= client->tls_data_left_to_send);
 690
 691         if (ret == -1 && errno == EAGAIN) {
 692                 // We're out of socket space, so now we're at the “low edge” of epoll's
 693                 // edge triggering. epoll will tell us when there is more room, so for now,
 694                 // just return.
 695                 // This is postcondition #4.
 696                 return true;
 697         }
 698         if (ret == -1) {
 699                 // Error! Postcondition #1.
 700                 log_perror("write");
 701                 close_client(client);
 702                 return true;
 703         }
 704         if (ret > 0 && size_t(ret) == client->tls_data_left_to_send) {
 705                 // All data has been sent, so we don't need to go to sleep.
 706                 tls_buffer_clear(client->tls_context);
 707                 client->tls_data_to_send = NULL;
 708                 return false;
 709         }
 710
 711         // More data to send, so try again.
 712         client->tls_data_to_send += ret;
 713         client->tls_data_left_to_send -= ret;
 714         goto send_data_again;
 715 }
 716
 717 int Server::read_nontls_data(Client *client, char *buf, size_t max_size)
 718 {
 719         int ret;
 720         do {
 721                 ret = read(client->sock, buf, max_size);
 722         } while (ret == -1 && errno == EINTR);
 723
 724         if (ret == -1 && errno == EAGAIN) {
 725                 // No more data right now. Nothing to do.
 726                 // This is postcondition #2.
 727                 return -1;
 728         }
 729         if (ret == -1) {
 730                 log_perror("read");
 731                 close_client(client);
 732                 return -1;
 733         }
 734         if (ret == 0) {
 735                 // OK, the socket is closed.
 736                 close_client(client);
 737                 return -1;
 738         }
 739
 740         return ret;
 741 }
 742
 743 int Server::read_tls_data(Client *client, char *buf, size_t max_size)
 744 {
 745 read_again:
 746         int ret;
 747         do {
 748                 ret = read(client->sock, buf, max_size);
 749         } while (ret == -1 && errno == EINTR);
 750
 751         if (ret == -1 && errno == EAGAIN) {
 752                 // No more data right now. Nothing to do.
 753                 // This is postcondition #2.
 754                 return -1;
 755         }
 756         if (ret == -1) {
 757                 log_perror("read");
 758                 close_client(client);
 759                 return -1;
 760         }
 761         if (ret == 0) {
 762                 // OK, the socket is closed.
 763                 close_client(client);
 764                 return -1;
 765         }
 766
 767         // Give it to the TLS library.
 768         int err = tls_consume_stream(client->tls_context, reinterpret_cast<const unsigned char *>(buf), ret, nullptr);
 769         if (err < 0) {
 770                 log_tls_error("tls_consume_stream", err);
 771                 close_client(client);
 772                 return -1;
 773         }
 774         if (err == 0) {
 775                 // Not consumed any data. See if we can read more.
 776                 goto read_again;
 777         }
 778
 779         // Read any decrypted data available for us. (We can reuse buf, since it's free now.)
 780         ret = tls_read(client->tls_context, reinterpret_cast<unsigned char *>(buf), max_size);
 781         if (ret == 0) {
 782                 // No decrypted data for us yet, but there might be some more handshaking
 783                 // to send. Do that if needed, then look for more data.
 784                 if (send_pending_tls_data(client)) {
 785                         // send_pending_tls_data() hit postconditions #1 or #4.
 786                         return -1;
 787                 }
 788                 goto read_again;
 789         }
 790         if (ret < 0) {
 791                 log_tls_error("tls_read", ret);
 792                 close_client(client);
 793                 return -1;
 794         }
 795
 796         assert(ret > 0);
 797         return ret;
 798 }
 799
 800 // See if there's some data we've lost. Ideally, we should drop to a block boundary,
 801 // but resync will be the mux's problem.
 802 void Server::skip_lost_data(Client *client)
 803 {
 804         Stream *stream = client->stream;
 805         if (stream == NULL) {
 806                 return;
 807         }
 808         size_t bytes_to_send = stream->bytes_received - client->stream_pos;
 809         if (bytes_to_send > stream->backlog_size) {
 810                 size_t bytes_lost = bytes_to_send - stream->backlog_size;
 811                 client->stream_pos = stream->bytes_received - stream->backlog_size;
 812                 client->bytes_lost += bytes_lost;
 813                 ++client->num_loss_events;
 814         }
 815 }
 816
 817 int Server::parse_request(Client *client)
 818 {
 819         vector<string> lines = split_lines(client->request);
 820         if (lines.empty()) {
 821                 return 400;  // Bad request (empty).
 822         }
 823
 824         // Parse the headers, for logging purposes.
 825         // TODO: Case-insensitivity.
 826         multimap<string, string> headers = extract_headers(lines, client->remote_addr);
 827         multimap<string, string>::const_iterator referer_it = headers.find("Referer");
 828         if (referer_it != headers.end()) {
 829                 client->referer = referer_it->second;
 830         }
 831         multimap<string, string>::const_iterator user_agent_it = headers.find("User-Agent");
 832         if (user_agent_it != headers.end()) {
 833                 client->user_agent = user_agent_it->second;
 834         }
 835
 836         vector<string> request_tokens = split_tokens(lines[0]);
 837         if (request_tokens.size() < 2) {
 838                 return 400;  // Bad request (empty).
 839         }
 840         if (request_tokens[0] != "GET") {
 841                 return 400;  // Should maybe be 405 instead?
 842         }
 843
 844         string url = request_tokens[1];
 845         client->url = url;
 846         if (url.size() > 8 && url.find("?backlog") == url.size() - 8) {
 847                 client->stream_pos = -2;
 848                 url = url.substr(0, url.size() - 8);
 849         } else {
 850                 client->stream_pos = -1;
 851         }
 852
 853         map<string, int>::const_iterator stream_url_map_it = stream_url_map.find(url);
 854         if (stream_url_map_it == stream_url_map.end()) {
 855                 map<string, string>::const_iterator ping_url_map_it = ping_url_map.find(url);
 856                 if (ping_url_map_it == ping_url_map.end()) {
 857                         return 404;  // Not found.
 858                 } else {
 859                         return 204;  // No error.
 860                 }
 861         }
 862
 863         Stream *stream = streams[stream_url_map_it->second];
 864         if (stream->http_header.empty()) {
 865                 return 503;  // Service unavailable.
 866         }
 867
 868         client->stream = stream;
 869         if (setsockopt(client->sock, SOL_SOCKET, SO_MAX_PACING_RATE, &client->stream->pacing_rate, sizeof(client->stream->pacing_rate)) == -1) {
 870                 if (client->stream->pacing_rate != ~0U) {
 871                         log_perror("setsockopt(SO_MAX_PACING_RATE)");
 872                 }
 873         }
 874         client->request.clear();
 875
 876         return 200;  // OK!
 877 }
 878
 879 void Server::construct_header(Client *client)
 880 {
 881         Stream *stream = client->stream;
 882         if (stream->encoding == Stream::STREAM_ENCODING_RAW) {
 883                 client->header_or_short_response = stream->http_header +
 884                         "\r\n" +
 885                         stream->stream_header;
 886         } else if (stream->encoding == Stream::STREAM_ENCODING_METACUBE) {
 887                 client->header_or_short_response = stream->http_header +
 888                         "Content-encoding: metacube\r\n" +
 889                         "\r\n";
 890                 if (!stream->stream_header.empty()) {
 891                         metacube2_block_header hdr;
 892                         memcpy(hdr.sync, METACUBE2_SYNC, sizeof(hdr.sync));
 893                         hdr.size = htonl(stream->stream_header.size());
 894                         hdr.flags = htons(METACUBE_FLAGS_HEADER);
 895                         hdr.csum = htons(metacube2_compute_crc(&hdr));
 896                         client->header_or_short_response.append(
 897                                 string(reinterpret_cast<char *>(&hdr), sizeof(hdr)));
 898                 }
 899                 client->header_or_short_response.append(stream->stream_header);
 900         } else {
 901                 assert(false);
 902         }
 903
 904         // Switch states.
 905         client->state = Client::SENDING_HEADER;
 906         change_epoll_events(client, EPOLLOUT | EPOLLET | EPOLLRDHUP);
 907 }
 908
 909 void Server::construct_error(Client *client, int error_code)
 910 {
 911         char error[256];
 912         snprintf(error, 256, "HTTP/1.0 %d Error\r\nContent-type: text/plain\r\n\r\nSomething went wrong. Sorry.\r\n",
 913                 error_code);
 914         client->header_or_short_response = error;
 915
 916         // Switch states.
 917         client->state = Client::SENDING_SHORT_RESPONSE;
 918         change_epoll_events(client, EPOLLOUT | EPOLLET | EPOLLRDHUP);
 919 }
 920
 921 void Server::construct_204(Client *client)
 922 {
 923         map<string, string>::const_iterator ping_url_map_it = ping_url_map.find(client->url);
 924         assert(ping_url_map_it != ping_url_map.end());
 925
 926         if (ping_url_map_it->second.empty()) {
 927                 client->header_or_short_response =
 928                         "HTTP/1.0 204 No Content\r\n"
 929                         "\r\n";
 930         } else {
 931                 char response[256];
 932                 snprintf(response, 256,
 933                          "HTTP/1.0 204 No Content\r\n"
 934                          "Access-Control-Allow-Origin: %s\r\n"
 935                          "\r\n",
 936                          ping_url_map_it->second.c_str());
 937                 client->header_or_short_response = response;
 938         }
 939
 940         // Switch states.
 941         client->state = Client::SENDING_SHORT_RESPONSE;
 942         change_epoll_events(client, EPOLLOUT | EPOLLET | EPOLLRDHUP);
 943 }
 944
 945 template<class T>
 946 void delete_from(vector<T> *v, T elem)
 947 {
 948         typename vector<T>::iterator new_end = remove(v->begin(), v->end(), elem);
 949         v->erase(new_end, v->end());
 950 }
 951
 952 void Server::close_client(Client *client)
 953 {
 954         if (epoll_ctl(epoll_fd, EPOLL_CTL_DEL, client->sock, NULL) == -1) {
 955                 log_perror("epoll_ctl(EPOLL_CTL_DEL)");
 956                 exit(1);
 957         }
 958
 959         // This client could be sleeping, so we'll need to fix that. (Argh, O(n).)
 960         if (client->stream != NULL) {
 961                 delete_from(&client->stream->sleeping_clients, client);
 962                 delete_from(&client->stream->to_process, client);
 963         }
 964
 965         if (client->tls_context) {
 966                 tls_destroy_context(client->tls_context);
 967         }
 968
 969         // Log to access_log.
 970         access_log->write(client->get_stats());
 971
 972         // Bye-bye!
 973         safe_close(client->sock);
 974
 975         clients.erase(client->sock);
 976 }
 977
 978 void Server::change_epoll_events(Client *client, uint32_t events)
 979 {
 980         epoll_event ev;
 981         ev.events = events;
 982         ev.data.ptr = client;
 983
 984         if (epoll_ctl(epoll_fd, EPOLL_CTL_MOD, client->sock, &ev) == -1) {
 985                 log_perror("epoll_ctl(EPOLL_CTL_MOD)");
 986                 exit(1);
 987         }
 988 }
 989
 990 void Server::process_queued_data()
 991 {
 992         {
 993                 MutexLock lock(&queued_clients_mutex);
 994
 995                 for (size_t i = 0; i < queued_add_clients.size(); ++i) {
 996                         add_client(queued_add_clients[i].first, queued_add_clients[i].second);
 997                 }
 998                 queued_add_clients.clear();
 999         }
1000
1001         for (size_t i = 0; i < streams.size(); ++i) {
1002                 streams[i]->process_queued_data();
1003         }
1004 }