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 "markpool.h"
  23 #include "metacube2.h"
  24 #include "mutexlock.h"
  25 #include "parse.h"
  26 #include "server.h"
  27 #include "state.pb.h"
  28 #include "stream.h"
  29 #include "util.h"
  30
  31 #ifndef SO_MAX_PACING_RATE
  32 #define SO_MAX_PACING_RATE 47
  33 #endif
  34
  35 using namespace std;
  36
  37 extern AccessLogThread *access_log;
  38
  39 Server::Server()
  40 {
  41         pthread_mutex_init(&mutex, NULL);
  42         pthread_mutex_init(&queued_clients_mutex, NULL);
  43
  44         epoll_fd = epoll_create(1024);  // Size argument is ignored.
  45         if (epoll_fd == -1) {
  46                 log_perror("epoll_fd");
  47                 exit(1);
  48         }
  49 }
  50
  51 Server::~Server()
  52 {
  53         for (size_t i = 0; i < streams.size(); ++i) {
  54                 delete streams[i];
  55         }
  56
  57         safe_close(epoll_fd);
  58 }
  59
  60 vector<ClientStats> Server::get_client_stats() const
  61 {
  62         vector<ClientStats> ret;
  63
  64         MutexLock lock(&mutex);
  65         for (map<int, Client>::const_iterator client_it = clients.begin();
  66              client_it != clients.end();
  67              ++client_it) {
  68                 ret.push_back(client_it->second.get_stats());
  69         }
  70         return ret;
  71 }
  72
  73 void Server::do_work()
  74 {
  75         while (!should_stop()) {
  76                 // Wait until there's activity on at least one of the fds,
  77                 // or 20 ms (about one frame at 50 fps) has elapsed.
  78                 //
  79                 // We could in theory wait forever and rely on wakeup()
  80                 // from add_client_deferred() and add_data_deferred(),
  81                 // but wakeup is a pretty expensive operation, and the
  82                 // two threads might end up fighting over a lock, so it's
  83                 // seemingly (much) more efficient to just have a timeout here.
  84                 int nfds = epoll_pwait(epoll_fd, events, EPOLL_MAX_EVENTS, EPOLL_TIMEOUT_MS, &sigset_without_usr1_block);
  85                 if (nfds == -1 && errno != EINTR) {
  86                         log_perror("epoll_wait");
  87                         exit(1);
  88                 }
  89
  90                 MutexLock lock(&mutex);  // We release the mutex between iterations.
  91
  92                 process_queued_data();
  93
  94                 for (int i = 0; i < nfds; ++i) {
  95                         Client *client = reinterpret_cast<Client *>(events[i].data.u64);
  96
  97                         if (events[i].events & (EPOLLERR | EPOLLRDHUP | EPOLLHUP)) {
  98                                 close_client(client);
  99                                 continue;
 100                         }
 101
 102                         process_client(client);
 103                 }
 104
 105                 for (size_t i = 0; i < streams.size(); ++i) {
 106                         vector<Client *> to_process;
 107                         swap(streams[i]->to_process, to_process);
 108                         for (size_t i = 0; i < to_process.size(); ++i) {
 109                                 process_client(to_process[i]);
 110                         }
 111                 }
 112         }
 113 }
 114
 115 CubemapStateProto Server::serialize()
 116 {
 117         // We don't serialize anything queued, so empty the queues.
 118         process_queued_data();
 119
 120         // Set all clients in a consistent state before serializing
 121         // (ie., they have no remaining lost data). Otherwise, increasing
 122         // the backlog could take clients into a newly valid area of the backlog,
 123         // sending a stream of zeros instead of skipping the data as it should.
 124         //
 125         // TODO: Do this when clients are added back from serialized state instead;
 126         // it would probably be less wasteful.
 127         for (map<int, Client>::iterator client_it = clients.begin();
 128              client_it != clients.end();
 129              ++client_it) {
 130                 skip_lost_data(&client_it->second);
 131         }
 132
 133         CubemapStateProto serialized;
 134         for (map<int, Client>::const_iterator client_it = clients.begin();
 135              client_it != clients.end();
 136              ++client_it) {
 137                 serialized.add_clients()->MergeFrom(client_it->second.serialize());
 138         }
 139         for (size_t i = 0; i < streams.size(); ++i) {
 140                 serialized.add_streams()->MergeFrom(streams[i]->serialize());
 141         }
 142         return serialized;
 143 }
 144
 145 void Server::add_client_deferred(int sock)
 146 {
 147         MutexLock lock(&queued_clients_mutex);
 148         queued_add_clients.push_back(sock);
 149 }
 150
 151 void Server::add_client(int sock)
 152 {
 153         pair<map<int, Client>::iterator, bool> ret =
 154                 clients.insert(make_pair(sock, Client(sock)));
 155         assert(ret.second == true);  // Should not already exist.
 156         Client *client_ptr = &ret.first->second;
 157
 158         // Start listening on data from this socket.
 159         epoll_event ev;
 160         ev.events = EPOLLIN | EPOLLET | EPOLLRDHUP;
 161         ev.data.u64 = reinterpret_cast<uint64_t>(client_ptr);
 162         if (epoll_ctl(epoll_fd, EPOLL_CTL_ADD, sock, &ev) == -1) {
 163                 log_perror("epoll_ctl(EPOLL_CTL_ADD)");
 164                 exit(1);
 165         }
 166
 167         process_client(client_ptr);
 168 }
 169
 170 void Server::add_client_from_serialized(const ClientProto &client)
 171 {
 172         MutexLock lock(&mutex);
 173         Stream *stream;
 174         int stream_index = lookup_stream_by_url(client.url());
 175         if (stream_index == -1) {
 176                 assert(client.state() != Client::SENDING_DATA);
 177                 stream = NULL;
 178         } else {
 179                 stream = streams[stream_index];
 180         }
 181         pair<map<int, Client>::iterator, bool> ret =
 182                 clients.insert(make_pair(client.sock(), Client(client, stream)));
 183         assert(ret.second == true);  // Should not already exist.
 184         Client *client_ptr = &ret.first->second;
 185
 186         // Start listening on data from this socket.
 187         epoll_event ev;
 188         if (client.state() == Client::READING_REQUEST) {
 189                 ev.events = EPOLLIN | EPOLLET | EPOLLRDHUP;
 190         } else {
 191                 // If we don't have more data for this client, we'll be putting it into
 192                 // the sleeping array again soon.
 193                 ev.events = EPOLLOUT | EPOLLET | EPOLLRDHUP;
 194         }
 195         ev.data.u64 = reinterpret_cast<uint64_t>(client_ptr);
 196         if (epoll_ctl(epoll_fd, EPOLL_CTL_ADD, client.sock(), &ev) == -1) {
 197                 log_perror("epoll_ctl(EPOLL_CTL_ADD)");
 198                 exit(1);
 199         }
 200
 201         if (client_ptr->state == Client::WAITING_FOR_KEYFRAME ||
 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, 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, 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_mark_pool(int stream_index, MarkPool *mark_pool)
 258 {
 259         MutexLock lock(&mutex);
 260         assert(clients.empty());
 261         assert(stream_index >= 0 && stream_index < ssize_t(streams.size()));
 262         streams[stream_index]->mark_pool = mark_pool;
 263 }
 264
 265 void Server::set_pacing_rate(int stream_index, uint32_t pacing_rate)
 266 {
 267         MutexLock lock(&mutex);
 268         assert(clients.empty());
 269         assert(stream_index >= 0 && stream_index < ssize_t(streams.size()));
 270         streams[stream_index]->pacing_rate = pacing_rate;
 271 }
 272
 273 void Server::add_data_deferred(int stream_index, const char *data, size_t bytes, StreamStartSuitability suitable_for_stream_start)
 274 {
 275         assert(stream_index >= 0 && stream_index < ssize_t(streams.size()));
 276         streams[stream_index]->add_data_deferred(data, bytes, suitable_for_stream_start);
 277 }
 278
 279 // See the .h file for postconditions after this function.
 280 void Server::process_client(Client *client)
 281 {
 282         switch (client->state) {
 283         case Client::READING_REQUEST: {
 284 read_request_again:
 285                 // Try to read more of the request.
 286                 char buf[1024];
 287                 int ret;
 288                 do {
 289                         ret = read(client->sock, buf, sizeof(buf));
 290                 } while (ret == -1 && errno == EINTR);
 291
 292                 if (ret == -1 && errno == EAGAIN) {
 293                         // No more data right now. Nothing to do.
 294                         // This is postcondition #2.
 295                         return;
 296                 }
 297                 if (ret == -1) {
 298                         log_perror("read");
 299                         close_client(client);
 300                         return;
 301                 }
 302                 if (ret == 0) {
 303                         // OK, the socket is closed.
 304                         close_client(client);
 305                         return;
 306                 }
 307
 308                 RequestParseStatus status = wait_for_double_newline(&client->request, buf, ret);
 309
 310                 switch (status) {
 311                 case RP_OUT_OF_SPACE:
 312                         log(WARNING, "[%s] Client sent overlong request!", client->remote_addr.c_str());
 313                         close_client(client);
 314                         return;
 315                 case RP_NOT_FINISHED_YET:
 316                         // OK, we don't have the entire header yet. Fine; we'll get it later.
 317                         // See if there's more data for us.
 318                         goto read_request_again;
 319                 case RP_EXTRA_DATA:
 320                         log(WARNING, "[%s] Junk data after request!", client->remote_addr.c_str());
 321                         close_client(client);
 322                         return;
 323                 case RP_FINISHED:
 324                         break;
 325                 }
 326
 327                 assert(status == RP_FINISHED);
 328
 329                 int error_code = parse_request(client);
 330                 if (error_code == 200) {
 331                         construct_header(client);
 332                 } else {
 333                         construct_error(client, error_code);
 334                 }
 335
 336                 // We've changed states, so fall through.
 337                 assert(client->state == Client::SENDING_ERROR ||
 338                        client->state == Client::SENDING_HEADER);
 339         }
 340         case Client::SENDING_ERROR:
 341         case Client::SENDING_HEADER: {
 342 sending_header_or_error_again:
 343                 int ret;
 344                 do {
 345                         ret = write(client->sock,
 346                                     client->header_or_error.data() + client->header_or_error_bytes_sent,
 347                                     client->header_or_error.size() - client->header_or_error_bytes_sent);
 348                 } while (ret == -1 && errno == EINTR);
 349
 350                 if (ret == -1 && errno == EAGAIN) {
 351                         // We're out of socket space, so now we're at the “low edge” of epoll's
 352                         // edge triggering. epoll will tell us when there is more room, so for now,
 353                         // just return.
 354                         // This is postcondition #4.
 355                         return;
 356                 }
 357
 358                 if (ret == -1) {
 359                         // Error! Postcondition #1.
 360                         log_perror("write");
 361                         close_client(client);
 362                         return;
 363                 }
 364
 365                 client->header_or_error_bytes_sent += ret;
 366                 assert(client->header_or_error_bytes_sent <= client->header_or_error.size());
 367
 368                 if (client->header_or_error_bytes_sent < client->header_or_error.size()) {
 369                         // We haven't sent all yet. Fine; go another round.
 370                         goto sending_header_or_error_again;
 371                 }
 372
 373                 // We're done sending the header or error! Clear it to release some memory.
 374                 client->header_or_error.clear();
 375
 376                 if (client->state == Client::SENDING_ERROR) {
 377                         // We're done sending the error, so now close.
 378                         // This is postcondition #1.
 379                         close_client(client);
 380                         return;
 381                 }
 382
 383                 // Start sending from the first keyframe we get. In other
 384                 // words, we won't send any of the backlog, but we'll start
 385                 // sending immediately as we get the next keyframe block.
 386                 // This is postcondition #3.
 387                 if (client->stream_pos == size_t(-2)) {
 388                         client->stream_pos = std::min<size_t>(
 389                             client->stream->bytes_received - client->stream->backlog_size,
 390                             0);
 391                         client->state = Client::SENDING_DATA;
 392                 } else {
 393                         // client->stream_pos should be -1, but it might not be,
 394                         // if we have clients from an older version.
 395                         client->stream_pos = client->stream->bytes_received;
 396                         client->state = Client::WAITING_FOR_KEYFRAME;
 397                 }
 398                 client->stream->put_client_to_sleep(client);
 399                 return;
 400         }
 401         case Client::WAITING_FOR_KEYFRAME: {
 402                 Stream *stream = client->stream;
 403                 if (ssize_t(client->stream_pos) > stream->last_suitable_starting_point) {
 404                         // We haven't received a keyframe since this stream started waiting,
 405                         // so keep on waiting for one.
 406                         // This is postcondition #3.
 407                         stream->put_client_to_sleep(client);
 408                         return;
 409                 }
 410                 client->stream_pos = stream->last_suitable_starting_point;
 411                 client->state = Client::SENDING_DATA;
 412                 // Fall through.
 413         }
 414         case Client::SENDING_DATA: {
 415                 skip_lost_data(client);
 416                 Stream *stream = client->stream;
 417
 418 sending_data_again:
 419                 size_t bytes_to_send = stream->bytes_received - client->stream_pos;
 420                 assert(bytes_to_send <= stream->backlog_size);
 421                 if (bytes_to_send == 0) {
 422                         return;
 423                 }
 424
 425                 // See if we need to split across the circular buffer.
 426                 bool more_data = false;
 427                 if ((client->stream_pos % stream->backlog_size) + bytes_to_send > stream->backlog_size) {
 428                         bytes_to_send = stream->backlog_size - (client->stream_pos % stream->backlog_size);
 429                         more_data = true;
 430                 }
 431
 432                 ssize_t ret;
 433                 do {
 434                         off_t offset = client->stream_pos % stream->backlog_size;
 435                         ret = sendfile(client->sock, stream->data_fd, &offset, bytes_to_send);
 436                 } while (ret == -1 && errno == EINTR);
 437
 438                 if (ret == -1 && errno == EAGAIN) {
 439                         // We're out of socket space, so return; epoll will wake us up
 440                         // when there is more room.
 441                         // This is postcondition #4.
 442                         return;
 443                 }
 444                 if (ret == -1) {
 445                         // Error, close; postcondition #1.
 446                         log_perror("sendfile");
 447                         close_client(client);
 448                         return;
 449                 }
 450                 client->stream_pos += ret;
 451                 client->bytes_sent += ret;
 452
 453                 if (client->stream_pos == stream->bytes_received) {
 454                         // We don't have any more data for this client, so put it to sleep.
 455                         // This is postcondition #3.
 456                         stream->put_client_to_sleep(client);
 457                 } else if (more_data && size_t(ret) == bytes_to_send) {
 458                         goto sending_data_again;
 459                 }
 460                 break;
 461         }
 462         default:
 463                 assert(false);
 464         }
 465 }
 466
 467 // See if there's some data we've lost. Ideally, we should drop to a block boundary,
 468 // but resync will be the mux's problem.
 469 void Server::skip_lost_data(Client *client)
 470 {
 471         Stream *stream = client->stream;
 472         if (stream == NULL) {
 473                 return;
 474         }
 475         size_t bytes_to_send = stream->bytes_received - client->stream_pos;
 476         if (bytes_to_send > stream->backlog_size) {
 477                 size_t bytes_lost = bytes_to_send - stream->backlog_size;
 478                 client->stream_pos = stream->bytes_received - stream->backlog_size;
 479                 client->bytes_lost += bytes_lost;
 480                 ++client->num_loss_events;
 481
 482                 double loss_fraction = double(client->bytes_lost) / double(client->bytes_lost + client->bytes_sent);
 483                 log(WARNING, "[%s] Client lost %lld bytes (total loss: %.2f%%), maybe too slow connection",
 484                         client->remote_addr.c_str(),
 485                         (long long int)(bytes_lost),
 486                         100.0 * loss_fraction);
 487         }
 488 }
 489
 490 int Server::parse_request(Client *client)
 491 {
 492         vector<string> lines = split_lines(client->request);
 493         if (lines.empty()) {
 494                 return 400;  // Bad request (empty).
 495         }
 496
 497         vector<string> request_tokens = split_tokens(lines[0]);
 498         if (request_tokens.size() < 2) {
 499                 return 400;  // Bad request (empty).
 500         }
 501         if (request_tokens[0] != "GET") {
 502                 return 400;  // Should maybe be 405 instead?
 503         }
 504
 505         string url = request_tokens[1];
 506         if (url.find("?backlog") == url.size() - 8) {
 507                 client->stream_pos = -2;
 508                 url = url.substr(0, url.size() - 8);
 509         } else {
 510                 client->stream_pos = -1;
 511         }
 512
 513         map<string, int>::const_iterator url_map_it = url_map.find(url);
 514         if (url_map_it == url_map.end()) {
 515                 return 404;  // Not found.
 516         }
 517
 518         Stream *stream = streams[url_map_it->second];
 519         if (stream->http_header.empty()) {
 520                 return 503;  // Service unavailable.
 521         }
 522
 523         client->url = request_tokens[1];
 524         client->stream = stream;
 525         if (client->stream->mark_pool != NULL) {
 526                 client->fwmark = client->stream->mark_pool->get_mark();
 527         } else {
 528                 client->fwmark = 0;  // No mark.
 529         }
 530         if (setsockopt(client->sock, SOL_SOCKET, SO_MARK, &client->fwmark, sizeof(client->fwmark)) == -1) {
 531                 if (client->fwmark != 0) {
 532                         log_perror("setsockopt(SO_MARK)");
 533                 }
 534         }
 535         if (setsockopt(client->sock, SOL_SOCKET, SO_MAX_PACING_RATE, &client->stream->pacing_rate, sizeof(client->stream->pacing_rate)) == -1) {
 536                 if (client->stream->pacing_rate != ~0U) {
 537                         log_perror("setsockopt(SO_MAX_PACING_RATE)");
 538                 }
 539         }
 540         client->request.clear();
 541
 542         return 200;  // OK!
 543 }
 544
 545 void Server::construct_header(Client *client)
 546 {
 547         Stream *stream = client->stream;
 548         if (stream->encoding == Stream::STREAM_ENCODING_RAW) {
 549                 client->header_or_error = stream->http_header +
 550                         "\r\n" +
 551                         stream->stream_header;
 552         } else if (stream->encoding == Stream::STREAM_ENCODING_METACUBE) {
 553                 client->header_or_error = stream->http_header +
 554                         "Content-encoding: metacube\r\n" +
 555                         "\r\n";
 556                 if (!stream->stream_header.empty()) {
 557                         metacube2_block_header hdr;
 558                         memcpy(hdr.sync, METACUBE2_SYNC, sizeof(hdr.sync));
 559                         hdr.size = htonl(stream->stream_header.size());
 560                         hdr.flags = htons(METACUBE_FLAGS_HEADER);
 561                         hdr.csum = htons(metacube2_compute_crc(&hdr));
 562                         client->header_or_error.append(
 563                                 string(reinterpret_cast<char *>(&hdr), sizeof(hdr)));
 564                 }
 565                 client->header_or_error.append(stream->stream_header);
 566         } else {
 567                 assert(false);
 568         }
 569
 570         // Switch states.
 571         client->state = Client::SENDING_HEADER;
 572
 573         epoll_event ev;
 574         ev.events = EPOLLOUT | EPOLLET | EPOLLRDHUP;
 575         ev.data.u64 = reinterpret_cast<uint64_t>(client);
 576
 577         if (epoll_ctl(epoll_fd, EPOLL_CTL_MOD, client->sock, &ev) == -1) {
 578                 log_perror("epoll_ctl(EPOLL_CTL_MOD)");
 579                 exit(1);
 580         }
 581 }
 582
 583 void Server::construct_error(Client *client, int error_code)
 584 {
 585         char error[256];
 586         snprintf(error, 256, "HTTP/1.0 %d Error\r\nContent-type: text/plain\r\n\r\nSomething went wrong. Sorry.\r\n",
 587                 error_code);
 588         client->header_or_error = error;
 589
 590         // Switch states.
 591         client->state = Client::SENDING_ERROR;
 592
 593         epoll_event ev;
 594         ev.events = EPOLLOUT | EPOLLET | EPOLLRDHUP;
 595         ev.data.u64 = reinterpret_cast<uint64_t>(client);
 596
 597         if (epoll_ctl(epoll_fd, EPOLL_CTL_MOD, client->sock, &ev) == -1) {
 598                 log_perror("epoll_ctl(EPOLL_CTL_MOD)");
 599                 exit(1);
 600         }
 601 }
 602
 603 template<class T>
 604 void delete_from(vector<T> *v, T elem)
 605 {
 606         typename vector<T>::iterator new_end = remove(v->begin(), v->end(), elem);
 607         v->erase(new_end, v->end());
 608 }
 609
 610 void Server::close_client(Client *client)
 611 {
 612         if (epoll_ctl(epoll_fd, EPOLL_CTL_DEL, client->sock, NULL) == -1) {
 613                 log_perror("epoll_ctl(EPOLL_CTL_DEL)");
 614                 exit(1);
 615         }
 616
 617         // This client could be sleeping, so we'll need to fix that. (Argh, O(n).)
 618         if (client->stream != NULL) {
 619                 delete_from(&client->stream->sleeping_clients, client);
 620                 delete_from(&client->stream->to_process, client);
 621                 if (client->stream->mark_pool != NULL) {
 622                         int fwmark = client->fwmark;
 623                         client->stream->mark_pool->release_mark(fwmark);
 624                 }
 625         }
 626
 627         // Log to access_log.
 628         access_log->write(client->get_stats());
 629
 630         // Bye-bye!
 631         safe_close(client->sock);
 632
 633         clients.erase(client->sock);
 634 }
 635
 636 void Server::process_queued_data()
 637 {
 638         {
 639                 MutexLock lock(&queued_clients_mutex);
 640
 641                 for (size_t i = 0; i < queued_add_clients.size(); ++i) {
 642                         add_client(queued_add_clients[i]);
 643                 }
 644                 queued_add_clients.clear();
 645         }
 646
 647         for (size_t i = 0; i < streams.size(); ++i) {
 648                 streams[i]->process_queued_data();
 649         }
 650 }