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

   1 #include <stdio.h>
   2 #include <string.h>
   3 #include <stdint.h>
   4 #include <assert.h>
   5 #include <arpa/inet.h>
   6 #include <curl/curl.h>
   7 #include <sys/socket.h>
   8 #include <pthread.h>
   9 #include <sys/types.h>
  10 #include <sys/ioctl.h>
  11 #include <sys/epoll.h>
  12 #include <errno.h>
  13 #include <vector>
  14 #include <string>
  15 #include <map>
  16 #include <algorithm>
  17
  18 #include "metacube.h"
  19 #include "server.h"
  20 #include "mutexlock.h"
  21 #include "parse.h"
  22 #include "state.pb.h"
  23
  24 using namespace std;
  25
  26 Client::Client(int sock)
  27         : sock(sock),
  28           state(Client::READING_REQUEST),
  29           stream(NULL),
  30           header_or_error_bytes_sent(0),
  31           bytes_sent(0)
  32 {
  33         request.reserve(1024);
  34 }
  35
  36 Client::Client(const ClientProto &serialized, Stream *stream)
  37         : sock(serialized.sock()),
  38           state(State(serialized.state())),
  39           request(serialized.request()),
  40           stream_id(serialized.stream_id()),
  41           stream(stream),
  42           header_or_error(serialized.header_or_error()),
  43           header_or_error_bytes_sent(serialized.header_or_error_bytes_sent()),
  44           bytes_sent(serialized.bytes_sent())
  45 {
  46 }
  47
  48 ClientProto Client::serialize() const
  49 {
  50         ClientProto serialized;
  51         serialized.set_sock(sock);
  52         serialized.set_state(state);
  53         serialized.set_request(request);
  54         serialized.set_stream_id(stream_id);
  55         serialized.set_header_or_error(header_or_error);
  56         serialized.set_header_or_error_bytes_sent(serialized.header_or_error_bytes_sent());
  57         serialized.set_bytes_sent(bytes_sent);
  58         return serialized;
  59 }
  60
  61 Stream::Stream(const string &stream_id)
  62         : stream_id(stream_id),
  63           data(new char[BACKLOG_SIZE]),
  64           data_size(0)
  65 {
  66         memset(data, 0, BACKLOG_SIZE);
  67 }
  68
  69 Stream::~Stream()
  70 {
  71         delete[] data;
  72 }
  73
  74 Stream::Stream(const StreamProto &serialized)
  75         : stream_id(serialized.stream_id()),
  76           header(serialized.header()),
  77           data(new char[BACKLOG_SIZE]),
  78           data_size(serialized.data_size())
  79 {
  80         assert(serialized.data().size() == BACKLOG_SIZE);
  81         memcpy(data, serialized.data().data(), BACKLOG_SIZE);
  82 }
  83
  84 StreamProto Stream::serialize() const
  85 {
  86         StreamProto serialized;
  87         serialized.set_header(header);
  88         serialized.set_data(string(data, data + BACKLOG_SIZE));
  89         serialized.set_data_size(data_size);
  90         serialized.set_stream_id(stream_id);
  91         return serialized;
  92 }
  93
  94 Server::Server()
  95 {
  96         pthread_mutex_init(&mutex, NULL);
  97
  98         epoll_fd = epoll_create(1024);  // Size argument is ignored.
  99         if (epoll_fd == -1) {
 100                 perror("epoll_fd");
 101                 exit(1);
 102         }
 103 }
 104
 105 Server::~Server()
 106 {
 107         int ret;
 108         do {
 109                 ret = close(epoll_fd);
 110         } while (ret == -1 && errno == EINTR);
 111
 112         if (ret == -1) {
 113                 perror("close(epoll_fd)");
 114         }
 115 }
 116
 117 void Server::run()
 118 {
 119         should_stop = false;
 120
 121         // Joinable is already the default, but it's good to be certain.
 122         pthread_attr_t attr;
 123         pthread_attr_init(&attr);
 124         pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_JOINABLE);
 125         pthread_create(&worker_thread, &attr, Server::do_work_thunk, this);
 126 }
 127
 128 void Server::stop()
 129 {
 130         {
 131                 MutexLock lock(&mutex);
 132                 should_stop = true;
 133         }
 134
 135         if (pthread_join(worker_thread, NULL) == -1) {
 136                 perror("pthread_join");
 137                 exit(1);
 138         }
 139 }
 140
 141 void *Server::do_work_thunk(void *arg)
 142 {
 143         Server *server = static_cast<Server *>(arg);
 144         server->do_work();
 145         return NULL;
 146 }
 147
 148 void Server::do_work()
 149 {
 150         for ( ;; ) {
 151                 int nfds = epoll_wait(epoll_fd, events, EPOLL_MAX_EVENTS, EPOLL_TIMEOUT_MS);
 152                 if (nfds == -1 && errno == EINTR) {
 153                         continue;
 154                 }
 155                 if (nfds == -1) {
 156                         perror("epoll_wait");
 157                         exit(1);
 158                 }
 159
 160                 MutexLock lock(&mutex);  // We release the mutex between iterations.
 161
 162                 if (should_stop) {
 163                         return;
 164                 }
 165
 166                 for (int i = 0; i < nfds; ++i) {
 167                         int fd = events[i].data.fd;
 168                         assert(clients.count(fd) != 0);
 169                         Client *client = &clients[fd];
 170
 171                         if (events[i].events & (EPOLLERR | EPOLLRDHUP | EPOLLHUP)) {
 172                                 close_client(client);
 173                                 continue;
 174                         }
 175
 176                         process_client(client);
 177                 }
 178         }
 179 }
 180
 181 CubemapStateProto Server::serialize() const
 182 {
 183         CubemapStateProto serialized;
 184         for (map<int, Client>::const_iterator client_it = clients.begin();
 185              client_it != clients.end();
 186              ++client_it) {
 187                 serialized.add_clients()->MergeFrom(client_it->second.serialize());
 188         }
 189         for (map<string, Stream *>::const_iterator stream_it = streams.begin();
 190              stream_it != streams.end();
 191              ++stream_it) {
 192                 serialized.add_streams()->MergeFrom(stream_it->second->serialize());
 193         }
 194         return serialized;
 195 }
 196
 197 void Server::add_client(int sock)
 198 {
 199         MutexLock lock(&mutex);
 200         clients.insert(make_pair(sock, Client(sock)));
 201
 202         // Start listening on data from this socket.
 203         epoll_event ev;
 204         ev.events = EPOLLIN | EPOLLRDHUP;
 205         ev.data.u64 = 0;  // Keep Valgrind happy.
 206         ev.data.fd = sock;
 207         if (epoll_ctl(epoll_fd, EPOLL_CTL_ADD, sock, &ev) == -1) {
 208                 perror("epoll_ctl(EPOLL_CTL_ADD)");
 209                 exit(1);
 210         }
 211 }
 212
 213 void Server::add_client_from_serialized(const ClientProto &client)
 214 {
 215         MutexLock lock(&mutex);
 216         Stream *stream = find_stream(client.stream_id());
 217         clients.insert(make_pair(client.sock(), Client(client, stream)));
 218
 219         // Start listening on data from this socket.
 220         epoll_event ev;
 221         if (client.state() == Client::READING_REQUEST) {
 222                 ev.events = EPOLLIN | EPOLLET | EPOLLRDHUP;
 223         } else {
 224                 // If we don't have more data for this client, we'll be putting it into
 225                 // the sleeping array again soon.
 226                 ev.events = EPOLLOUT | EPOLLET | EPOLLRDHUP;
 227         }
 228         ev.data.u64 = 0;  // Keep Valgrind happy.
 229         ev.data.fd = client.sock();
 230         if (epoll_ctl(epoll_fd, EPOLL_CTL_ADD, client.sock(), &ev) == -1) {
 231                 perror("epoll_ctl(EPOLL_CTL_ADD)");
 232                 exit(1);
 233         }
 234
 235         process_client(&clients[client.sock()]);
 236 }
 237
 238 void Server::add_stream(const string &stream_id)
 239 {
 240         MutexLock lock(&mutex);
 241         streams.insert(make_pair(stream_id, new Stream(stream_id)));
 242 }
 243
 244 void Server::add_stream_from_serialized(const StreamProto &stream)
 245 {
 246         MutexLock lock(&mutex);
 247         streams.insert(make_pair(stream.stream_id(), new Stream(stream)));
 248 }
 249
 250 void Server::set_header(const string &stream_id, const string &header)
 251 {
 252         MutexLock lock(&mutex);
 253         find_stream(stream_id)->header = header;
 254
 255         // If there are clients we haven't sent anything to yet, we should give
 256         // them the header, so push back into the SENDING_HEADER state.
 257         for (map<int, Client>::iterator client_it = clients.begin();
 258              client_it != clients.end();
 259              ++client_it) {
 260                 Client *client = &client_it->second;
 261                 if (client->state == Client::SENDING_DATA &&
 262                     client->bytes_sent == 0) {
 263                         construct_header(client);
 264                 }
 265         }
 266 }
 267
 268 void Server::add_data(const string &stream_id, const char *data, size_t bytes)
 269 {
 270         if (bytes == 0) {
 271                 return;
 272         }
 273
 274         MutexLock lock(&mutex);
 275         Stream *stream = find_stream(stream_id);
 276         size_t pos = stream->data_size % BACKLOG_SIZE;
 277         stream->data_size += bytes;
 278
 279         if (pos + bytes > BACKLOG_SIZE) {
 280                 size_t to_copy = BACKLOG_SIZE - pos;
 281                 memcpy(stream->data + pos, data, to_copy);
 282                 data += to_copy;
 283                 bytes -= to_copy;
 284                 pos = 0;
 285         }
 286
 287         memcpy(stream->data + pos, data, bytes);
 288         wake_up_all_clients();
 289 }
 290
 291 // See the .h file for postconditions after this function.
 292 void Server::process_client(Client *client)
 293 {
 294         switch (client->state) {
 295         case Client::READING_REQUEST: {
 296 read_request_again:
 297                 // Try to read more of the request.
 298                 char buf[1024];
 299                 int ret;
 300                 do {
 301                         ret = read(client->sock, buf, sizeof(buf));
 302                 } while (ret == -1 && errno == EINTR);
 303
 304                 if (ret == -1 && errno == EAGAIN) {
 305                         // No more data right now. Nothing to do.
 306                         // This is postcondition #2.
 307                         return;
 308                 }
 309                 if (ret == -1) {
 310                         perror("read");
 311                         close_client(client);
 312                         return;
 313                 }
 314                 if (ret == 0) {
 315                         // OK, the socket is closed.
 316                         close_client(client);
 317                         return;
 318                 }
 319
 320                 // Guard against overlong requests gobbling up all of our space.
 321                 if (client->request.size() + ret > MAX_CLIENT_REQUEST) {
 322                         fprintf(stderr, "WARNING: fd %d sent overlong request!\n", client->sock);
 323                         close_client(client);
 324                         return;
 325                 }
 326
 327                 // See if we have \r\n\r\n anywhere in the request. We start three bytes
 328                 // before what we just appended, in case we just got the final character.
 329                 size_t existing_req_bytes = client->request.size();
 330                 client->request.append(string(buf, buf + ret));
 331
 332                 size_t start_at = (existing_req_bytes >= 3 ? existing_req_bytes - 3 : 0);
 333                 const char *ptr = reinterpret_cast<char *>(
 334                         memmem(client->request.data() + start_at, client->request.size() - start_at,
 335                                "\r\n\r\n", 4));
 336                 if (ptr == NULL) {
 337                         // OK, we don't have the entire header yet. Fine; we'll get it later.
 338                         // See if there's more data for us.
 339                         goto read_request_again;
 340                 }
 341
 342                 if (ptr != client->request.data() + client->request.size() - 4) {
 343                         fprintf(stderr, "WARNING: fd %d had junk data after request!\n", client->sock);
 344                         close_client(client);
 345                         return;
 346                 }
 347
 348                 int error_code = parse_request(client);
 349                 if (error_code == 200) {
 350                         construct_header(client);
 351                 } else {
 352                         construct_error(client, error_code);
 353                 }
 354
 355                 // We've changed states, so fall through.
 356                 assert(client->state == Client::SENDING_ERROR ||
 357                        client->state == Client::SENDING_HEADER);
 358         }
 359         case Client::SENDING_ERROR:
 360         case Client::SENDING_HEADER: {
 361 sending_header_or_error_again:
 362                 int ret;
 363                 do {
 364                         ret = write(client->sock,
 365                                     client->header_or_error.data() + client->header_or_error_bytes_sent,
 366                                     client->header_or_error.size() - client->header_or_error_bytes_sent);
 367                 } while (ret == -1 && errno == EINTR);
 368
 369                 if (ret == -1 && errno == EAGAIN) {
 370                         // We're out of socket space, so now we're at the “low edge” of epoll's
 371                         // edge triggering. epoll will tell us when there is more room, so for now,
 372                         // just return.
 373                         // This is postcondition #4.
 374                         return;
 375                 }
 376
 377                 if (ret == -1) {
 378                         // Error! Postcondition #1.
 379                         perror("write");
 380                         close_client(client);
 381                         return;
 382                 }
 383
 384                 client->header_or_error_bytes_sent += ret;
 385                 assert(client->header_or_error_bytes_sent <= client->header_or_error.size());
 386
 387                 if (client->header_or_error_bytes_sent < client->header_or_error.size()) {
 388                         // We haven't sent all yet. Fine; go another round.
 389                         goto sending_header_or_error_again;
 390                 }
 391
 392                 // We're done sending the header or error! Clear it to release some memory.
 393                 client->header_or_error.clear();
 394
 395                 if (client->state == Client::SENDING_ERROR) {
 396                         // We're done sending the error, so now close.
 397                         // This is postcondition #1.
 398                         close_client(client);
 399                         return;
 400                 }
 401
 402                 // Start sending from the end. In other words, we won't send any of the backlog,
 403                 // but we'll start sending immediately as we get data.
 404                 // This is postcondition #3.
 405                 client->state = Client::SENDING_DATA;
 406                 client->bytes_sent = client->stream->data_size;
 407                 put_client_to_sleep(client);
 408                 return;
 409         }
 410         case Client::SENDING_DATA: {
 411                 // See if there's some data we've lost. Ideally, we should drop to a block boundary,
 412                 // but resync will be the mux's problem.
 413                 const Stream *stream = client->stream;
 414                 size_t bytes_to_send = stream->data_size - client->bytes_sent;
 415                 if (bytes_to_send == 0) {
 416                         return;
 417                 }
 418                 if (bytes_to_send > BACKLOG_SIZE) {
 419                         fprintf(stderr, "WARNING: fd %d lost %lld bytes, maybe too slow connection\n",
 420                                 client->sock,
 421                                 (long long int)(bytes_to_send - BACKLOG_SIZE));
 422                         client->bytes_sent = stream->data_size - BACKLOG_SIZE;
 423                         bytes_to_send = BACKLOG_SIZE;
 424                 }
 425
 426                 // See if we need to split across the circular buffer.
 427                 ssize_t ret;
 428                 if ((client->bytes_sent % BACKLOG_SIZE) + bytes_to_send > BACKLOG_SIZE) {
 429                         size_t bytes_first_part = BACKLOG_SIZE - (client->bytes_sent % BACKLOG_SIZE);
 430
 431                         iovec iov[2];
 432                         iov[0].iov_base = const_cast<char *>(stream->data + (client->bytes_sent % BACKLOG_SIZE));
 433                         iov[0].iov_len = bytes_first_part;
 434
 435                         iov[1].iov_base = const_cast<char *>(stream->data);
 436                         iov[1].iov_len = bytes_to_send - bytes_first_part;
 437
 438                         do {
 439                                 ret = writev(client->sock, iov, 2);
 440                         } while (ret == -1 && errno == EINTR);
 441                 } else {
 442                         do {
 443                                 ret = write(client->sock,
 444                                             stream->data + (client->bytes_sent % BACKLOG_SIZE),
 445                                             bytes_to_send);
 446                         } while (ret == -1 && errno == EINTR);
 447                 }
 448                 if (ret == -1 && errno == EAGAIN) {
 449                         // We're out of socket space, so return; epoll will wake us up
 450                         // when there is more room.
 451                         // This is postcondition #4.
 452                         return;
 453                 }
 454                 if (ret == -1) {
 455                         // Error, close; postcondition #1.
 456                         perror("write/writev");
 457                         close_client(client);
 458                         return;
 459                 }
 460                 client->bytes_sent += ret;
 461
 462                 if (client->bytes_sent == stream->data_size) {
 463                         // We don't have any more data for this client, so put it to sleep.
 464                         // This is postcondition #3.
 465                         put_client_to_sleep(client);
 466                 } else {
 467                         // XXX: Do we need to go another round here to explicitly
 468                         // get the EAGAIN?
 469                 }
 470                 break;
 471         }
 472         default:
 473                 assert(false);
 474         }
 475 }
 476
 477 int Server::parse_request(Client *client)
 478 {
 479         vector<string> lines = split_lines(client->request);
 480         if (lines.empty()) {
 481                 return 400;  // Bad request (empty).
 482         }
 483
 484         vector<string> request_tokens = split_tokens(lines[0]);
 485         if (request_tokens.size() < 2) {
 486                 return 400;  // Bad request (empty).
 487         }
 488         if (request_tokens[0] != "GET") {
 489                 return 400;  // Should maybe be 405 instead?
 490         }
 491         if (streams.count(request_tokens[1]) == 0) {
 492                 return 404;  // Not found.
 493         }
 494
 495         client->stream_id = request_tokens[1];
 496         client->stream = find_stream(client->stream_id);
 497         client->request.clear();
 498
 499         return 200;  // OK!
 500 }
 501
 502 void Server::construct_header(Client *client)
 503 {
 504         client->header_or_error = "HTTP/1.0 200 OK\r\nContent-type: video/x-flv\r\nCache-Control: no-cache\r\n\r\n" +
 505                 find_stream(client->stream_id)->header;
 506
 507         // Switch states.
 508         client->state = Client::SENDING_HEADER;
 509
 510         epoll_event ev;
 511         ev.events = EPOLLOUT | EPOLLET | EPOLLRDHUP;
 512         ev.data.u64 = 0;  // Keep Valgrind happy.
 513         ev.data.fd = client->sock;
 514
 515         if (epoll_ctl(epoll_fd, EPOLL_CTL_MOD, client->sock, &ev) == -1) {
 516                 perror("epoll_ctl(EPOLL_CTL_MOD)");
 517                 exit(1);
 518         }
 519 }
 520
 521 void Server::construct_error(Client *client, int error_code)
 522 {
 523         char error[256];
 524         snprintf(error, 256, "HTTP/1.0 %d Error\r\nContent-type: text/plain\r\n\r\nSomething went wrong. Sorry.\r\n",
 525                 error_code);
 526         client->header_or_error = error;
 527
 528         // Switch states.
 529         client->state = Client::SENDING_ERROR;
 530
 531         epoll_event ev;
 532         ev.events = EPOLLOUT | EPOLLET | EPOLLRDHUP;
 533         ev.data.u64 = 0;  // Keep Valgrind happy.
 534         ev.data.fd = client->sock;
 535
 536         if (epoll_ctl(epoll_fd, EPOLL_CTL_MOD, client->sock, &ev) == -1) {
 537                 perror("epoll_ctl(EPOLL_CTL_MOD)");
 538                 exit(1);
 539         }
 540 }
 541
 542 void Server::close_client(Client *client)
 543 {
 544         if (epoll_ctl(epoll_fd, EPOLL_CTL_DEL, client->sock, NULL) == -1) {
 545                 perror("epoll_ctl(EPOLL_CTL_DEL)");
 546                 exit(1);
 547         }
 548
 549         // This client could be sleeping, so we'll need to fix that. (Argh, O(n).)
 550         vector<Client *>::iterator new_end =
 551                 remove(sleeping_clients.begin(), sleeping_clients.end(), client);
 552         sleeping_clients.erase(new_end, sleeping_clients.end());
 553
 554         // Bye-bye!
 555         int ret;
 556         do {
 557                 ret = close(client->sock);
 558         } while (ret == -1 && errno == EINTR);
 559
 560         if (ret == -1) {
 561                 perror("close");
 562         }
 563
 564         clients.erase(client->sock);
 565 }
 566
 567 void Server::put_client_to_sleep(Client *client)
 568 {
 569         sleeping_clients.push_back(client);
 570 }
 571
 572 void Server::wake_up_all_clients()
 573 {
 574         vector<Client *> to_process;
 575         swap(sleeping_clients, to_process);
 576         for (unsigned i = 0; i < to_process.size(); ++i) {
 577                 process_client(to_process[i]);
 578         }
 579 }
 580
 581 Stream *Server::find_stream(const string &stream_id)
 582 {
 583         map<string, Stream *>::iterator it = streams.find(stream_id);
 584         assert(it != streams.end());
 585         return it->second;
 586 }