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::PREBUFFERING ||
 202             (client_ptr->state == Client::SENDING_DATA &&
 203              client_ptr->stream_pos == client_ptr->stream->bytes_received)) {
 204                 client_ptr->stream->put_client_to_sleep(client_ptr);
 205         } else {
 206                 process_client(client_ptr);
 207         }
 208 }
 209
 210 int Server::lookup_stream_by_url(const std::string &url) const
 211 {
 212         map<string, int>::const_iterator url_it = url_map.find(url);
 213         if (url_it == url_map.end()) {
 214                 return -1;
 215         }
 216         return url_it->second;
 217 }
 218
 219 int Server::add_stream(const string &url, size_t backlog_size, size_t prebuffering_bytes, Stream::Encoding encoding)
 220 {
 221         MutexLock lock(&mutex);
 222         url_map.insert(make_pair(url, streams.size()));
 223         streams.push_back(new Stream(url, backlog_size, prebuffering_bytes, encoding));
 224         return streams.size() - 1;
 225 }
 226
 227 int Server::add_stream_from_serialized(const StreamProto &stream, int data_fd)
 228 {
 229         MutexLock lock(&mutex);
 230         url_map.insert(make_pair(stream.url(), streams.size()));
 231         streams.push_back(new Stream(stream, data_fd));
 232         return streams.size() - 1;
 233 }
 234
 235 void Server::set_backlog_size(int stream_index, size_t new_size)
 236 {
 237         MutexLock lock(&mutex);
 238         assert(stream_index >= 0 && stream_index < ssize_t(streams.size()));
 239         streams[stream_index]->set_backlog_size(new_size);
 240 }
 241
 242 void Server::set_encoding(int stream_index, Stream::Encoding encoding)
 243 {
 244         MutexLock lock(&mutex);
 245         assert(stream_index >= 0 && stream_index < ssize_t(streams.size()));
 246         streams[stream_index]->encoding = encoding;
 247 }
 248
 249 void Server::set_header(int stream_index, const string &http_header, const string &stream_header)
 250 {
 251         MutexLock lock(&mutex);
 252         assert(stream_index >= 0 && stream_index < ssize_t(streams.size()));
 253         streams[stream_index]->http_header = http_header;
 254         streams[stream_index]->stream_header = stream_header;
 255 }
 256
 257 void Server::set_pacing_rate(int stream_index, uint32_t pacing_rate)
 258 {
 259         MutexLock lock(&mutex);
 260         assert(clients.empty());
 261         assert(stream_index >= 0 && stream_index < ssize_t(streams.size()));
 262         streams[stream_index]->pacing_rate = pacing_rate;
 263 }
 264
 265 void Server::add_data_deferred(int stream_index, const char *data, size_t bytes, StreamStartSuitability suitable_for_stream_start)
 266 {
 267         assert(stream_index >= 0 && stream_index < ssize_t(streams.size()));
 268         streams[stream_index]->add_data_deferred(data, bytes, suitable_for_stream_start);
 269 }
 270
 271 // See the .h file for postconditions after this function.
 272 void Server::process_client(Client *client)
 273 {
 274         switch (client->state) {
 275         case Client::READING_REQUEST: {
 276 read_request_again:
 277                 // Try to read more of the request.
 278                 char buf[1024];
 279                 int ret;
 280                 do {
 281                         ret = read(client->sock, buf, sizeof(buf));
 282                 } while (ret == -1 && errno == EINTR);
 283
 284                 if (ret == -1 && errno == EAGAIN) {
 285                         // No more data right now. Nothing to do.
 286                         // This is postcondition #2.
 287                         return;
 288                 }
 289                 if (ret == -1) {
 290                         log_perror("read");
 291                         close_client(client);
 292                         return;
 293                 }
 294                 if (ret == 0) {
 295                         // OK, the socket is closed.
 296                         close_client(client);
 297                         return;
 298                 }
 299
 300                 RequestParseStatus status = wait_for_double_newline(&client->request, buf, ret);
 301
 302                 switch (status) {
 303                 case RP_OUT_OF_SPACE:
 304                         log(WARNING, "[%s] Client sent overlong request!", client->remote_addr.c_str());
 305                         close_client(client);
 306                         return;
 307                 case RP_NOT_FINISHED_YET:
 308                         // OK, we don't have the entire header yet. Fine; we'll get it later.
 309                         // See if there's more data for us.
 310                         goto read_request_again;
 311                 case RP_EXTRA_DATA:
 312                         log(WARNING, "[%s] Junk data after request!", client->remote_addr.c_str());
 313                         close_client(client);
 314                         return;
 315                 case RP_FINISHED:
 316                         break;
 317                 }
 318
 319                 assert(status == RP_FINISHED);
 320
 321                 int error_code = parse_request(client);
 322                 if (error_code == 200) {
 323                         construct_header(client);
 324                 } else {
 325                         construct_error(client, error_code);
 326                 }
 327
 328                 // We've changed states, so fall through.
 329                 assert(client->state == Client::SENDING_ERROR ||
 330                        client->state == Client::SENDING_HEADER);
 331         }
 332         case Client::SENDING_ERROR:
 333         case Client::SENDING_HEADER: {
 334 sending_header_or_error_again:
 335                 int ret;
 336                 do {
 337                         ret = write(client->sock,
 338                                     client->header_or_error.data() + client->header_or_error_bytes_sent,
 339                                     client->header_or_error.size() - client->header_or_error_bytes_sent);
 340                 } while (ret == -1 && errno == EINTR);
 341
 342                 if (ret == -1 && errno == EAGAIN) {
 343                         // We're out of socket space, so now we're at the “low edge” of epoll's
 344                         // edge triggering. epoll will tell us when there is more room, so for now,
 345                         // just return.
 346                         // This is postcondition #4.
 347                         return;
 348                 }
 349
 350                 if (ret == -1) {
 351                         // Error! Postcondition #1.
 352                         log_perror("write");
 353                         close_client(client);
 354                         return;
 355                 }
 356
 357                 client->header_or_error_bytes_sent += ret;
 358                 assert(client->header_or_error_bytes_sent <= client->header_or_error.size());
 359
 360                 if (client->header_or_error_bytes_sent < client->header_or_error.size()) {
 361                         // We haven't sent all yet. Fine; go another round.
 362                         goto sending_header_or_error_again;
 363                 }
 364
 365                 // We're done sending the header or error! Clear it to release some memory.
 366                 client->header_or_error.clear();
 367
 368                 if (client->state == Client::SENDING_ERROR) {
 369                         // We're done sending the error, so now close.
 370                         // This is postcondition #1.
 371                         close_client(client);
 372                         return;
 373                 }
 374
 375                 // Start sending from the first keyframe we get. In other
 376                 // words, we won't send any of the backlog, but we'll start
 377                 // sending immediately as we get the next keyframe block.
 378                 // This is postcondition #3.
 379                 if (client->stream_pos == size_t(-2)) {
 380                         client->stream_pos = std::min<size_t>(
 381                             client->stream->bytes_received - client->stream->backlog_size,
 382                             0);
 383                         client->state = Client::SENDING_DATA;
 384                 } else {
 385                         // client->stream_pos should be -1, but it might not be,
 386                         // if we have clients from an older version.
 387                         client->stream_pos = client->stream->bytes_received;
 388                         client->state = Client::WAITING_FOR_KEYFRAME;
 389                 }
 390                 client->stream->put_client_to_sleep(client);
 391                 return;
 392         }
 393         case Client::WAITING_FOR_KEYFRAME: {
 394                 Stream *stream = client->stream;
 395                 if (ssize_t(client->stream_pos) > stream->last_suitable_starting_point) {
 396                         // We haven't received a keyframe since this stream started waiting,
 397                         // so keep on waiting for one.
 398                         // This is postcondition #3.
 399                         stream->put_client_to_sleep(client);
 400                         return;
 401                 }
 402                 client->stream_pos = stream->last_suitable_starting_point;
 403                 client->state = Client::PREBUFFERING;
 404                 // Fall through.
 405         }
 406         case Client::PREBUFFERING: {
 407                 Stream *stream = client->stream;
 408                 size_t bytes_to_send = stream->bytes_received - client->stream_pos;
 409                 assert(bytes_to_send <= stream->backlog_size);
 410                 if (bytes_to_send < stream->prebuffering_bytes) {
 411                         // We don't have enough bytes buffered to start this client yet.
 412                         stream->put_client_to_sleep(client);
 413                         return;
 414                 }
 415                 client->state = Client::SENDING_DATA;
 416                 // Fall through.
 417         }
 418         case Client::SENDING_DATA: {
 419                 skip_lost_data(client);
 420                 Stream *stream = client->stream;
 421
 422 sending_data_again:
 423                 size_t bytes_to_send = stream->bytes_received - client->stream_pos;
 424                 assert(bytes_to_send <= stream->backlog_size);
 425                 if (bytes_to_send == 0) {
 426                         return;
 427                 }
 428
 429                 // See if we need to split across the circular buffer.
 430                 bool more_data = false;
 431                 if ((client->stream_pos % stream->backlog_size) + bytes_to_send > stream->backlog_size) {
 432                         bytes_to_send = stream->backlog_size - (client->stream_pos % stream->backlog_size);
 433                         more_data = true;
 434                 }
 435
 436                 ssize_t ret;
 437                 do {
 438                         off_t offset = client->stream_pos % stream->backlog_size;
 439                         ret = sendfile(client->sock, stream->data_fd, &offset, bytes_to_send);
 440                 } while (ret == -1 && errno == EINTR);
 441
 442                 if (ret == -1 && errno == EAGAIN) {
 443                         // We're out of socket space, so return; epoll will wake us up
 444                         // when there is more room.
 445                         // This is postcondition #4.
 446                         return;
 447                 }
 448                 if (ret == -1) {
 449                         // Error, close; postcondition #1.
 450                         log_perror("sendfile");
 451                         close_client(client);
 452                         return;
 453                 }
 454                 client->stream_pos += ret;
 455                 client->bytes_sent += ret;
 456
 457                 if (client->stream_pos == stream->bytes_received) {
 458                         // We don't have any more data for this client, so put it to sleep.
 459                         // This is postcondition #3.
 460                         stream->put_client_to_sleep(client);
 461                 } else if (more_data && size_t(ret) == bytes_to_send) {
 462                         goto sending_data_again;
 463                 }
 464                 break;
 465         }
 466         default:
 467                 assert(false);
 468         }
 469 }
 470
 471 // See if there's some data we've lost. Ideally, we should drop to a block boundary,
 472 // but resync will be the mux's problem.
 473 void Server::skip_lost_data(Client *client)
 474 {
 475         Stream *stream = client->stream;
 476         if (stream == NULL) {
 477                 return;
 478         }
 479         size_t bytes_to_send = stream->bytes_received - client->stream_pos;
 480         if (bytes_to_send > stream->backlog_size) {
 481                 size_t bytes_lost = bytes_to_send - stream->backlog_size;
 482                 client->stream_pos = stream->bytes_received - stream->backlog_size;
 483                 client->bytes_lost += bytes_lost;
 484                 ++client->num_loss_events;
 485         }
 486 }
 487
 488 int Server::parse_request(Client *client)
 489 {
 490         vector<string> lines = split_lines(client->request);
 491         if (lines.empty()) {
 492                 return 400;  // Bad request (empty).
 493         }
 494
 495         vector<string> request_tokens = split_tokens(lines[0]);
 496         if (request_tokens.size() < 2) {
 497                 return 400;  // Bad request (empty).
 498         }
 499         if (request_tokens[0] != "GET") {
 500                 return 400;  // Should maybe be 405 instead?
 501         }
 502
 503         string url = request_tokens[1];
 504         if (url.find("?backlog") == url.size() - 8) {
 505                 client->stream_pos = -2;
 506                 url = url.substr(0, url.size() - 8);
 507         } else {
 508                 client->stream_pos = -1;
 509         }
 510
 511         map<string, int>::const_iterator url_map_it = url_map.find(url);
 512         if (url_map_it == url_map.end()) {
 513                 return 404;  // Not found.
 514         }
 515
 516         Stream *stream = streams[url_map_it->second];
 517         if (stream->http_header.empty()) {
 518                 return 503;  // Service unavailable.
 519         }
 520
 521         client->url = request_tokens[1];
 522         client->stream = stream;
 523         if (setsockopt(client->sock, SOL_SOCKET, SO_MAX_PACING_RATE, &client->stream->pacing_rate, sizeof(client->stream->pacing_rate)) == -1) {
 524                 if (client->stream->pacing_rate != ~0U) {
 525                         log_perror("setsockopt(SO_MAX_PACING_RATE)");
 526                 }
 527         }
 528         client->request.clear();
 529
 530         return 200;  // OK!
 531 }
 532
 533 void Server::construct_header(Client *client)
 534 {
 535         Stream *stream = client->stream;
 536         if (stream->encoding == Stream::STREAM_ENCODING_RAW) {
 537                 client->header_or_error = stream->http_header +
 538                         "\r\n" +
 539                         stream->stream_header;
 540         } else if (stream->encoding == Stream::STREAM_ENCODING_METACUBE) {
 541                 client->header_or_error = stream->http_header +
 542                         "Content-encoding: metacube\r\n" +
 543                         "\r\n";
 544                 if (!stream->stream_header.empty()) {
 545                         metacube2_block_header hdr;
 546                         memcpy(hdr.sync, METACUBE2_SYNC, sizeof(hdr.sync));
 547                         hdr.size = htonl(stream->stream_header.size());
 548                         hdr.flags = htons(METACUBE_FLAGS_HEADER);
 549                         hdr.csum = htons(metacube2_compute_crc(&hdr));
 550                         client->header_or_error.append(
 551                                 string(reinterpret_cast<char *>(&hdr), sizeof(hdr)));
 552                 }
 553                 client->header_or_error.append(stream->stream_header);
 554         } else {
 555                 assert(false);
 556         }
 557
 558         // Switch states.
 559         client->state = Client::SENDING_HEADER;
 560
 561         epoll_event ev;
 562         ev.events = EPOLLOUT | EPOLLET | EPOLLRDHUP;
 563         ev.data.u64 = reinterpret_cast<uint64_t>(client);
 564
 565         if (epoll_ctl(epoll_fd, EPOLL_CTL_MOD, client->sock, &ev) == -1) {
 566                 log_perror("epoll_ctl(EPOLL_CTL_MOD)");
 567                 exit(1);
 568         }
 569 }
 570
 571 void Server::construct_error(Client *client, int error_code)
 572 {
 573         char error[256];
 574         snprintf(error, 256, "HTTP/1.0 %d Error\r\nContent-type: text/plain\r\n\r\nSomething went wrong. Sorry.\r\n",
 575                 error_code);
 576         client->header_or_error = error;
 577
 578         // Switch states.
 579         client->state = Client::SENDING_ERROR;
 580
 581         epoll_event ev;
 582         ev.events = EPOLLOUT | EPOLLET | EPOLLRDHUP;
 583         ev.data.u64 = reinterpret_cast<uint64_t>(client);
 584
 585         if (epoll_ctl(epoll_fd, EPOLL_CTL_MOD, client->sock, &ev) == -1) {
 586                 log_perror("epoll_ctl(EPOLL_CTL_MOD)");
 587                 exit(1);
 588         }
 589 }
 590
 591 template<class T>
 592 void delete_from(vector<T> *v, T elem)
 593 {
 594         typename vector<T>::iterator new_end = remove(v->begin(), v->end(), elem);
 595         v->erase(new_end, v->end());
 596 }
 597
 598 void Server::close_client(Client *client)
 599 {
 600         if (epoll_ctl(epoll_fd, EPOLL_CTL_DEL, client->sock, NULL) == -1) {
 601                 log_perror("epoll_ctl(EPOLL_CTL_DEL)");
 602                 exit(1);
 603         }
 604
 605         // This client could be sleeping, so we'll need to fix that. (Argh, O(n).)
 606         if (client->stream != NULL) {
 607                 delete_from(&client->stream->sleeping_clients, client);
 608                 delete_from(&client->stream->to_process, client);
 609         }
 610
 611         // Log to access_log.
 612         access_log->write(client->get_stats());
 613
 614         // Bye-bye!
 615         safe_close(client->sock);
 616
 617         clients.erase(client->sock);
 618 }
 619
 620 void Server::process_queued_data()
 621 {
 622         {
 623                 MutexLock lock(&queued_clients_mutex);
 624
 625                 for (size_t i = 0; i < queued_add_clients.size(); ++i) {
 626                         add_client(queued_add_clients[i]);
 627                 }
 628                 queued_add_clients.clear();
 629         }
 630
 631         for (size_t i = 0; i < streams.size(); ++i) {
 632                 streams[i]->process_queued_data();
 633         }
 634 }