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 "accesslog.h"
  21 #include "log.h"
  22 #include "metacube2.h"
  23 #include "mutexlock.h"
  24 #include "parse.h"
  25 #include "server.h"
  26 #include "state.pb.h"
  27 #include "stream.h"
  28 #include "util.h"
  29
  30 #ifndef SO_MAX_PACING_RATE
  31 #define SO_MAX_PACING_RATE 47
  32 #endif
  33
  34 using namespace std;
  35
  36 extern AccessLogThread *access_log;
  37
  38 Server::Server()
  39 {
  40         pthread_mutex_init(&mutex, NULL);
  41         pthread_mutex_init(&queued_clients_mutex, NULL);
  42
  43         epoll_fd = epoll_create(1024);  // Size argument is ignored.
  44         if (epoll_fd == -1) {
  45                 log_perror("epoll_fd");
  46                 exit(1);
  47         }
  48 }
  49
  50 Server::~Server()
  51 {
  52         for (size_t i = 0; i < streams.size(); ++i) {
  53                 delete streams[i];
  54         }
  55
  56         safe_close(epoll_fd);
  57 }
  58
  59 vector<ClientStats> Server::get_client_stats() const
  60 {
  61         vector<ClientStats> ret;
  62
  63         MutexLock lock(&mutex);
  64         for (map<int, Client>::const_iterator client_it = clients.begin();
  65              client_it != clients.end();
  66              ++client_it) {
  67                 ret.push_back(client_it->second.get_stats());
  68         }
  69         return ret;
  70 }
  71
  72 void Server::do_work()
  73 {
  74         while (!should_stop()) {
  75                 // Wait until there's activity on at least one of the fds,
  76                 // or 20 ms (about one frame at 50 fps) has elapsed.
  77                 //
  78                 // We could in theory wait forever and rely on wakeup()
  79                 // from add_client_deferred() and add_data_deferred(),
  80                 // but wakeup is a pretty expensive operation, and the
  81                 // two threads might end up fighting over a lock, so it's
  82                 // seemingly (much) more efficient to just have a timeout here.
  83                 int nfds = epoll_pwait(epoll_fd, events, EPOLL_MAX_EVENTS, EPOLL_TIMEOUT_MS, &sigset_without_usr1_block);
  84                 if (nfds == -1 && errno != EINTR) {
  85                         log_perror("epoll_wait");
  86                         exit(1);
  87                 }
  88
  89                 MutexLock lock(&mutex);  // We release the mutex between iterations.
  90
  91                 process_queued_data();
  92
  93                 for (int i = 0; i < nfds; ++i) {
  94                         Client *client = reinterpret_cast<Client *>(events[i].data.u64);
  95
  96                         if (events[i].events & (EPOLLERR | EPOLLRDHUP | EPOLLHUP)) {
  97                                 close_client(client);
  98                                 continue;
  99                         }
 100
 101                         process_client(client);
 102                 }
 103
 104                 for (size_t i = 0; i < streams.size(); ++i) {
 105                         vector<Client *> to_process;
 106                         swap(streams[i]->to_process, to_process);
 107                         for (size_t i = 0; i < to_process.size(); ++i) {
 108                                 process_client(to_process[i]);
 109                         }
 110                 }
 111         }
 112 }
 113
 114 CubemapStateProto Server::serialize()
 115 {
 116         // We don't serialize anything queued, so empty the queues.
 117         process_queued_data();
 118
 119         // Set all clients in a consistent state before serializing
 120         // (ie., they have no remaining lost data). Otherwise, increasing
 121         // the backlog could take clients into a newly valid area of the backlog,
 122         // sending a stream of zeros instead of skipping the data as it should.
 123         //
 124         // TODO: Do this when clients are added back from serialized state instead;
 125         // it would probably be less wasteful.
 126         for (map<int, Client>::iterator client_it = clients.begin();
 127              client_it != clients.end();
 128              ++client_it) {
 129                 skip_lost_data(&client_it->second);
 130         }
 131
 132         CubemapStateProto serialized;
 133         for (map<int, Client>::const_iterator client_it = clients.begin();
 134              client_it != clients.end();
 135              ++client_it) {
 136                 serialized.add_clients()->MergeFrom(client_it->second.serialize());
 137         }
 138         for (size_t i = 0; i < streams.size(); ++i) {
 139                 serialized.add_streams()->MergeFrom(streams[i]->serialize());
 140         }
 141         return serialized;
 142 }
 143
 144 void Server::add_client_deferred(int sock)
 145 {
 146         MutexLock lock(&queued_clients_mutex);
 147         queued_add_clients.push_back(sock);
 148 }
 149
 150 void Server::add_client(int sock)
 151 {
 152         pair<map<int, Client>::iterator, bool> ret =
 153                 clients.insert(make_pair(sock, Client(sock)));
 154         assert(ret.second == true);  // Should not already exist.
 155         Client *client_ptr = &ret.first->second;
 156
 157         // Start listening on data from this socket.
 158         epoll_event ev;
 159         ev.events = EPOLLIN | EPOLLET | EPOLLRDHUP;
 160         ev.data.u64 = reinterpret_cast<uint64_t>(client_ptr);
 161         if (epoll_ctl(epoll_fd, EPOLL_CTL_ADD, sock, &ev) == -1) {
 162                 log_perror("epoll_ctl(EPOLL_CTL_ADD)");
 163                 exit(1);
 164         }
 165
 166         process_client(client_ptr);
 167 }
 168
 169 void Server::add_client_from_serialized(const ClientProto &client)
 170 {
 171         MutexLock lock(&mutex);
 172         Stream *stream;
 173         int stream_index = lookup_stream_by_url(client.url());
 174         if (stream_index == -1) {
 175                 assert(client.state() != Client::SENDING_DATA);
 176                 stream = NULL;
 177         } else {
 178                 stream = streams[stream_index];
 179         }
 180         pair<map<int, Client>::iterator, bool> ret =
 181                 clients.insert(make_pair(client.sock(), Client(client, stream)));
 182         assert(ret.second == true);  // Should not already exist.
 183         Client *client_ptr = &ret.first->second;
 184
 185         // Start listening on data from this socket.
 186         epoll_event ev;
 187         if (client.state() == Client::READING_REQUEST) {
 188                 ev.events = EPOLLIN | EPOLLET | EPOLLRDHUP;
 189         } else {
 190                 // If we don't have more data for this client, we'll be putting it into
 191                 // the sleeping array again soon.
 192                 ev.events = EPOLLOUT | EPOLLET | EPOLLRDHUP;
 193         }
 194         ev.data.u64 = reinterpret_cast<uint64_t>(client_ptr);
 195         if (epoll_ctl(epoll_fd, EPOLL_CTL_ADD, client.sock(), &ev) == -1) {
 196                 log_perror("epoll_ctl(EPOLL_CTL_ADD)");
 197                 exit(1);
 198         }
 199
 200         if (client_ptr->state == Client::WAITING_FOR_KEYFRAME ||
 201             (client_ptr->state == Client::SENDING_DATA &&
 202              client_ptr->stream_pos == client_ptr->stream->bytes_received)) {
 203                 client_ptr->stream->put_client_to_sleep(client_ptr);
 204         } else {
 205                 process_client(client_ptr);
 206         }
 207 }
 208
 209 int Server::lookup_stream_by_url(const std::string &url) const
 210 {
 211         map<string, int>::const_iterator url_it = url_map.find(url);
 212         if (url_it == url_map.end()) {
 213                 return -1;
 214         }
 215         return url_it->second;
 216 }
 217
 218 int Server::add_stream(const string &url, size_t backlog_size, Stream::Encoding encoding)
 219 {
 220         MutexLock lock(&mutex);
 221         url_map.insert(make_pair(url, streams.size()));
 222         streams.push_back(new Stream(url, backlog_size, encoding));
 223         return streams.size() - 1;
 224 }
 225
 226 int Server::add_stream_from_serialized(const StreamProto &stream, int data_fd)
 227 {
 228         MutexLock lock(&mutex);
 229         url_map.insert(make_pair(stream.url(), streams.size()));
 230         streams.push_back(new Stream(stream, data_fd));
 231         return streams.size() - 1;
 232 }
 233
 234 void Server::set_backlog_size(int stream_index, size_t new_size)
 235 {
 236         MutexLock lock(&mutex);
 237         assert(stream_index >= 0 && stream_index < ssize_t(streams.size()));
 238         streams[stream_index]->set_backlog_size(new_size);
 239 }
 240
 241 void Server::set_encoding(int stream_index, Stream::Encoding encoding)
 242 {
 243         MutexLock lock(&mutex);
 244         assert(stream_index >= 0 && stream_index < ssize_t(streams.size()));
 245         streams[stream_index]->encoding = encoding;
 246 }
 247
 248 void Server::set_header(int stream_index, const string &http_header, const string &stream_header)
 249 {
 250         MutexLock lock(&mutex);
 251         assert(stream_index >= 0 && stream_index < ssize_t(streams.size()));
 252         streams[stream_index]->http_header = http_header;
 253         streams[stream_index]->stream_header = stream_header;
 254 }
 255
 256 void Server::set_pacing_rate(int stream_index, uint32_t pacing_rate)
 257 {
 258         MutexLock lock(&mutex);
 259         assert(clients.empty());
 260         assert(stream_index >= 0 && stream_index < ssize_t(streams.size()));
 261         streams[stream_index]->pacing_rate = pacing_rate;
 262 }
 263
 264 void Server::add_data_deferred(int stream_index, const char *data, size_t bytes, StreamStartSuitability suitable_for_stream_start)
 265 {
 266         assert(stream_index >= 0 && stream_index < ssize_t(streams.size()));
 267         streams[stream_index]->add_data_deferred(data, bytes, suitable_for_stream_start);
 268 }
 269
 270 // See the .h file for postconditions after this function.
 271 void Server::process_client(Client *client)
 272 {
 273         switch (client->state) {
 274         case Client::READING_REQUEST: {
 275 read_request_again:
 276                 // Try to read more of the request.
 277                 char buf[1024];
 278                 int ret;
 279                 do {
 280                         ret = read(client->sock, buf, sizeof(buf));
 281                 } while (ret == -1 && errno == EINTR);
 282
 283                 if (ret == -1 && errno == EAGAIN) {
 284                         // No more data right now. Nothing to do.
 285                         // This is postcondition #2.
 286                         return;
 287                 }
 288                 if (ret == -1) {
 289                         log_perror("read");
 290                         close_client(client);
 291                         return;
 292                 }
 293                 if (ret == 0) {
 294                         // OK, the socket is closed.
 295                         close_client(client);
 296                         return;
 297                 }
 298
 299                 RequestParseStatus status = wait_for_double_newline(&client->request, buf, ret);
 300
 301                 switch (status) {
 302                 case RP_OUT_OF_SPACE:
 303                         log(WARNING, "[%s] Client sent overlong request!", client->remote_addr.c_str());
 304                         close_client(client);
 305                         return;
 306                 case RP_NOT_FINISHED_YET:
 307                         // OK, we don't have the entire header yet. Fine; we'll get it later.
 308                         // See if there's more data for us.
 309                         goto read_request_again;
 310                 case RP_EXTRA_DATA:
 311                         log(WARNING, "[%s] Junk data after request!", client->remote_addr.c_str());
 312                         close_client(client);
 313                         return;
 314                 case RP_FINISHED:
 315                         break;
 316                 }
 317
 318                 assert(status == RP_FINISHED);
 319
 320                 int error_code = parse_request(client);
 321                 if (error_code == 200) {
 322                         construct_header(client);
 323                 } else {
 324                         construct_error(client, error_code);
 325                 }
 326
 327                 // We've changed states, so fall through.
 328                 assert(client->state == Client::SENDING_ERROR ||
 329                        client->state == Client::SENDING_HEADER);
 330         }
 331         case Client::SENDING_ERROR:
 332         case Client::SENDING_HEADER: {
 333 sending_header_or_error_again:
 334                 int ret;
 335                 do {
 336                         ret = write(client->sock,
 337                                     client->header_or_error.data() + client->header_or_error_bytes_sent,
 338                                     client->header_or_error.size() - client->header_or_error_bytes_sent);
 339                 } while (ret == -1 && errno == EINTR);
 340
 341                 if (ret == -1 && errno == EAGAIN) {
 342                         // We're out of socket space, so now we're at the “low edge” of epoll's
 343                         // edge triggering. epoll will tell us when there is more room, so for now,
 344                         // just return.
 345                         // This is postcondition #4.
 346                         return;
 347                 }
 348
 349                 if (ret == -1) {
 350                         // Error! Postcondition #1.
 351                         log_perror("write");
 352                         close_client(client);
 353                         return;
 354                 }
 355
 356                 client->header_or_error_bytes_sent += ret;
 357                 assert(client->header_or_error_bytes_sent <= client->header_or_error.size());
 358
 359                 if (client->header_or_error_bytes_sent < client->header_or_error.size()) {
 360                         // We haven't sent all yet. Fine; go another round.
 361                         goto sending_header_or_error_again;
 362                 }
 363
 364                 // We're done sending the header or error! Clear it to release some memory.
 365                 client->header_or_error.clear();
 366
 367                 if (client->state == Client::SENDING_ERROR) {
 368                         // We're done sending the error, so now close.
 369                         // This is postcondition #1.
 370                         close_client(client);
 371                         return;
 372                 }
 373
 374                 // Start sending from the first keyframe we get. In other
 375                 // words, we won't send any of the backlog, but we'll start
 376                 // sending immediately as we get the next keyframe block.
 377                 // This is postcondition #3.
 378                 if (client->stream_pos == size_t(-2)) {
 379                         client->stream_pos = std::min<size_t>(
 380                             client->stream->bytes_received - client->stream->backlog_size,
 381                             0);
 382                         client->state = Client::SENDING_DATA;
 383                 } else {
 384                         // client->stream_pos should be -1, but it might not be,
 385                         // if we have clients from an older version.
 386                         client->stream_pos = client->stream->bytes_received;
 387                         client->state = Client::WAITING_FOR_KEYFRAME;
 388                 }
 389                 client->stream->put_client_to_sleep(client);
 390                 return;
 391         }
 392         case Client::WAITING_FOR_KEYFRAME: {
 393                 Stream *stream = client->stream;
 394                 if (ssize_t(client->stream_pos) > stream->last_suitable_starting_point) {
 395                         // We haven't received a keyframe since this stream started waiting,
 396                         // so keep on waiting for one.
 397                         // This is postcondition #3.
 398                         stream->put_client_to_sleep(client);
 399                         return;
 400                 }
 401                 client->stream_pos = stream->last_suitable_starting_point;
 402                 client->state = Client::SENDING_DATA;
 403                 // Fall through.
 404         }
 405         case Client::SENDING_DATA: {
 406                 skip_lost_data(client);
 407                 Stream *stream = client->stream;
 408
 409 sending_data_again:
 410                 size_t bytes_to_send = stream->bytes_received - client->stream_pos;
 411                 assert(bytes_to_send <= stream->backlog_size);
 412                 if (bytes_to_send == 0) {
 413                         return;
 414                 }
 415
 416                 // See if we need to split across the circular buffer.
 417                 bool more_data = false;
 418                 if ((client->stream_pos % stream->backlog_size) + bytes_to_send > stream->backlog_size) {
 419                         bytes_to_send = stream->backlog_size - (client->stream_pos % stream->backlog_size);
 420                         more_data = true;
 421                 }
 422
 423                 ssize_t ret;
 424                 do {
 425                         off_t offset = client->stream_pos % stream->backlog_size;
 426                         ret = sendfile(client->sock, stream->data_fd, &offset, bytes_to_send);
 427                 } while (ret == -1 && errno == EINTR);
 428
 429                 if (ret == -1 && errno == EAGAIN) {
 430                         // We're out of socket space, so return; epoll will wake us up
 431                         // when there is more room.
 432                         // This is postcondition #4.
 433                         return;
 434                 }
 435                 if (ret == -1) {
 436                         // Error, close; postcondition #1.
 437                         log_perror("sendfile");
 438                         close_client(client);
 439                         return;
 440                 }
 441                 client->stream_pos += ret;
 442                 client->bytes_sent += ret;
 443
 444                 if (client->stream_pos == stream->bytes_received) {
 445                         // We don't have any more data for this client, so put it to sleep.
 446                         // This is postcondition #3.
 447                         stream->put_client_to_sleep(client);
 448                 } else if (more_data && size_t(ret) == bytes_to_send) {
 449                         goto sending_data_again;
 450                 }
 451                 break;
 452         }
 453         default:
 454                 assert(false);
 455         }
 456 }
 457
 458 // See if there's some data we've lost. Ideally, we should drop to a block boundary,
 459 // but resync will be the mux's problem.
 460 void Server::skip_lost_data(Client *client)
 461 {
 462         Stream *stream = client->stream;
 463         if (stream == NULL) {
 464                 return;
 465         }
 466         size_t bytes_to_send = stream->bytes_received - client->stream_pos;
 467         if (bytes_to_send > stream->backlog_size) {
 468                 size_t bytes_lost = bytes_to_send - stream->backlog_size;
 469                 client->stream_pos = stream->bytes_received - stream->backlog_size;
 470                 client->bytes_lost += bytes_lost;
 471                 ++client->num_loss_events;
 472         }
 473 }
 474
 475 int Server::parse_request(Client *client)
 476 {
 477         vector<string> lines = split_lines(client->request);
 478         if (lines.empty()) {
 479                 return 400;  // Bad request (empty).
 480         }
 481
 482         vector<string> request_tokens = split_tokens(lines[0]);
 483         if (request_tokens.size() < 2) {
 484                 return 400;  // Bad request (empty).
 485         }
 486         if (request_tokens[0] != "GET") {
 487                 return 400;  // Should maybe be 405 instead?
 488         }
 489
 490         string url = request_tokens[1];
 491         if (url.find("?backlog") == url.size() - 8) {
 492                 client->stream_pos = -2;
 493                 url = url.substr(0, url.size() - 8);
 494         } else {
 495                 client->stream_pos = -1;
 496         }
 497
 498         map<string, int>::const_iterator url_map_it = url_map.find(url);
 499         if (url_map_it == url_map.end()) {
 500                 return 404;  // Not found.
 501         }
 502
 503         Stream *stream = streams[url_map_it->second];
 504         if (stream->http_header.empty()) {
 505                 return 503;  // Service unavailable.
 506         }
 507
 508         client->url = request_tokens[1];
 509         client->stream = stream;
 510         if (setsockopt(client->sock, SOL_SOCKET, SO_MAX_PACING_RATE, &client->stream->pacing_rate, sizeof(client->stream->pacing_rate)) == -1) {
 511                 if (client->stream->pacing_rate != ~0U) {
 512                         log_perror("setsockopt(SO_MAX_PACING_RATE)");
 513                 }
 514         }
 515         client->request.clear();
 516
 517         return 200;  // OK!
 518 }
 519
 520 void Server::construct_header(Client *client)
 521 {
 522         Stream *stream = client->stream;
 523         if (stream->encoding == Stream::STREAM_ENCODING_RAW) {
 524                 client->header_or_error = stream->http_header +
 525                         "\r\n" +
 526                         stream->stream_header;
 527         } else if (stream->encoding == Stream::STREAM_ENCODING_METACUBE) {
 528                 client->header_or_error = stream->http_header +
 529                         "Content-encoding: metacube\r\n" +
 530                         "\r\n";
 531                 if (!stream->stream_header.empty()) {
 532                         metacube2_block_header hdr;
 533                         memcpy(hdr.sync, METACUBE2_SYNC, sizeof(hdr.sync));
 534                         hdr.size = htonl(stream->stream_header.size());
 535                         hdr.flags = htons(METACUBE_FLAGS_HEADER);
 536                         hdr.csum = htons(metacube2_compute_crc(&hdr));
 537                         client->header_or_error.append(
 538                                 string(reinterpret_cast<char *>(&hdr), sizeof(hdr)));
 539                 }
 540                 client->header_or_error.append(stream->stream_header);
 541         } else {
 542                 assert(false);
 543         }
 544
 545         // Switch states.
 546         client->state = Client::SENDING_HEADER;
 547
 548         epoll_event ev;
 549         ev.events = EPOLLOUT | EPOLLET | EPOLLRDHUP;
 550         ev.data.u64 = reinterpret_cast<uint64_t>(client);
 551
 552         if (epoll_ctl(epoll_fd, EPOLL_CTL_MOD, client->sock, &ev) == -1) {
 553                 log_perror("epoll_ctl(EPOLL_CTL_MOD)");
 554                 exit(1);
 555         }
 556 }
 557
 558 void Server::construct_error(Client *client, int error_code)
 559 {
 560         char error[256];
 561         snprintf(error, 256, "HTTP/1.0 %d Error\r\nContent-type: text/plain\r\n\r\nSomething went wrong. Sorry.\r\n",
 562                 error_code);
 563         client->header_or_error = error;
 564
 565         // Switch states.
 566         client->state = Client::SENDING_ERROR;
 567
 568         epoll_event ev;
 569         ev.events = EPOLLOUT | EPOLLET | EPOLLRDHUP;
 570         ev.data.u64 = reinterpret_cast<uint64_t>(client);
 571
 572         if (epoll_ctl(epoll_fd, EPOLL_CTL_MOD, client->sock, &ev) == -1) {
 573                 log_perror("epoll_ctl(EPOLL_CTL_MOD)");
 574                 exit(1);
 575         }
 576 }
 577
 578 template<class T>
 579 void delete_from(vector<T> *v, T elem)
 580 {
 581         typename vector<T>::iterator new_end = remove(v->begin(), v->end(), elem);
 582         v->erase(new_end, v->end());
 583 }
 584
 585 void Server::close_client(Client *client)
 586 {
 587         if (epoll_ctl(epoll_fd, EPOLL_CTL_DEL, client->sock, NULL) == -1) {
 588                 log_perror("epoll_ctl(EPOLL_CTL_DEL)");
 589                 exit(1);
 590         }
 591
 592         // This client could be sleeping, so we'll need to fix that. (Argh, O(n).)
 593         if (client->stream != NULL) {
 594                 delete_from(&client->stream->sleeping_clients, client);
 595                 delete_from(&client->stream->to_process, client);
 596         }
 597
 598         // Log to access_log.
 599         access_log->write(client->get_stats());
 600
 601         // Bye-bye!
 602         safe_close(client->sock);
 603
 604         clients.erase(client->sock);
 605 }
 606
 607 void Server::process_queued_data()
 608 {
 609         {
 610                 MutexLock lock(&queued_clients_mutex);
 611
 612                 for (size_t i = 0; i < queued_add_clients.size(); ++i) {
 613                         add_client(queued_add_clients[i]);
 614                 }
 615                 queued_add_clients.clear();
 616         }
 617
 618         for (size_t i = 0; i < streams.size(); ++i) {
 619                 streams[i]->process_queued_data();
 620         }
 621 }