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 void Stream::put_client_to_sleep(Client *client)
  95 {
  96         sleeping_clients.push_back(client);
  97 }
  98
  99 void Stream::wake_up_all_clients()
 100 {
 101         if (to_process.empty()) {
 102                 swap(sleeping_clients, to_process);
 103         } else {
 104                 to_process.insert(to_process.end(), sleeping_clients.begin(), sleeping_clients.end());
 105                 sleeping_clients.clear();
 106         }
 107 }
 108
 109 Server::Server()
 110 {
 111         pthread_mutex_init(&mutex, NULL);
 112
 113         epoll_fd = epoll_create(1024);  // Size argument is ignored.
 114         if (epoll_fd == -1) {
 115                 perror("epoll_fd");
 116                 exit(1);
 117         }
 118 }
 119
 120 Server::~Server()
 121 {
 122         int ret;
 123         do {
 124                 ret = close(epoll_fd);
 125         } while (ret == -1 && errno == EINTR);
 126
 127         if (ret == -1) {
 128                 perror("close(epoll_fd)");
 129         }
 130 }
 131
 132 void Server::run()
 133 {
 134         should_stop = false;
 135
 136         // Joinable is already the default, but it's good to be certain.
 137         pthread_attr_t attr;
 138         pthread_attr_init(&attr);
 139         pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_JOINABLE);
 140         pthread_create(&worker_thread, &attr, Server::do_work_thunk, this);
 141 }
 142
 143 void Server::stop()
 144 {
 145         {
 146                 MutexLock lock(&mutex);
 147                 should_stop = true;
 148         }
 149
 150         if (pthread_join(worker_thread, NULL) == -1) {
 151                 perror("pthread_join");
 152                 exit(1);
 153         }
 154 }
 155
 156 void *Server::do_work_thunk(void *arg)
 157 {
 158         Server *server = static_cast<Server *>(arg);
 159         server->do_work();
 160         return NULL;
 161 }
 162
 163 void Server::do_work()
 164 {
 165         for ( ;; ) {
 166                 int nfds = epoll_wait(epoll_fd, events, EPOLL_MAX_EVENTS, EPOLL_TIMEOUT_MS);
 167                 if (nfds == -1 && errno == EINTR) {
 168                         continue;
 169                 }
 170                 if (nfds == -1) {
 171                         perror("epoll_wait");
 172                         exit(1);
 173                 }
 174
 175                 MutexLock lock(&mutex);  // We release the mutex between iterations.
 176
 177                 if (should_stop) {
 178                         return;
 179                 }
 180
 181                 for (int i = 0; i < nfds; ++i) {
 182                         int fd = events[i].data.fd;
 183                         assert(clients.count(fd) != 0);
 184                         Client *client = &clients[fd];
 185
 186                         if (events[i].events & (EPOLLERR | EPOLLRDHUP | EPOLLHUP)) {
 187                                 close_client(client);
 188                                 continue;
 189                         }
 190
 191                         process_client(client);
 192                 }
 193
 194                 for (map<string, Stream *>::iterator stream_it = streams.begin();
 195                      stream_it != streams.end();
 196                      ++stream_it) {
 197                         Stream *stream = stream_it->second;
 198                         for (size_t i = 0; i < stream->to_process.size(); ++i) {
 199                                 process_client(stream->to_process[i]);
 200                         }
 201                         stream->to_process.clear();
 202                 }
 203         }
 204 }
 205
 206 CubemapStateProto Server::serialize() const
 207 {
 208         CubemapStateProto serialized;
 209         for (map<int, Client>::const_iterator client_it = clients.begin();
 210              client_it != clients.end();
 211              ++client_it) {
 212                 serialized.add_clients()->MergeFrom(client_it->second.serialize());
 213         }
 214         for (map<string, Stream *>::const_iterator stream_it = streams.begin();
 215              stream_it != streams.end();
 216              ++stream_it) {
 217                 serialized.add_streams()->MergeFrom(stream_it->second->serialize());
 218         }
 219         return serialized;
 220 }
 221
 222 void Server::add_client(int sock)
 223 {
 224         MutexLock lock(&mutex);
 225         clients.insert(make_pair(sock, Client(sock)));
 226
 227         // Start listening on data from this socket.
 228         epoll_event ev;
 229         ev.events = EPOLLIN | EPOLLET | EPOLLRDHUP;
 230         ev.data.u64 = 0;  // Keep Valgrind happy.
 231         ev.data.fd = sock;
 232         if (epoll_ctl(epoll_fd, EPOLL_CTL_ADD, sock, &ev) == -1) {
 233                 perror("epoll_ctl(EPOLL_CTL_ADD)");
 234                 exit(1);
 235         }
 236
 237         process_client(&clients[sock]);
 238 }
 239
 240 void Server::add_client_from_serialized(const ClientProto &client)
 241 {
 242         MutexLock lock(&mutex);
 243         Stream *stream = find_stream(client.stream_id());
 244         clients.insert(make_pair(client.sock(), Client(client, stream)));
 245         Client *client_ptr = &clients[client.sock()];
 246
 247         // Start listening on data from this socket.
 248         epoll_event ev;
 249         if (client.state() == Client::READING_REQUEST) {
 250                 ev.events = EPOLLIN | EPOLLET | EPOLLRDHUP;
 251         } else {
 252                 // If we don't have more data for this client, we'll be putting it into
 253                 // the sleeping array again soon.
 254                 ev.events = EPOLLOUT | EPOLLET | EPOLLRDHUP;
 255         }
 256         ev.data.u64 = 0;  // Keep Valgrind happy.
 257         ev.data.fd = client.sock();
 258         if (epoll_ctl(epoll_fd, EPOLL_CTL_ADD, client.sock(), &ev) == -1) {
 259                 perror("epoll_ctl(EPOLL_CTL_ADD)");
 260                 exit(1);
 261         }
 262
 263         if (client_ptr->state == Client::SENDING_DATA &&
 264             client_ptr->bytes_sent == client_ptr->stream->data_size) {
 265                 client_ptr->stream->put_client_to_sleep(client_ptr);
 266         } else {
 267                 process_client(client_ptr);
 268         }
 269 }
 270
 271 void Server::add_stream(const string &stream_id)
 272 {
 273         MutexLock lock(&mutex);
 274         streams.insert(make_pair(stream_id, new Stream(stream_id)));
 275 }
 276
 277 void Server::add_stream_from_serialized(const StreamProto &stream)
 278 {
 279         MutexLock lock(&mutex);
 280         streams.insert(make_pair(stream.stream_id(), new Stream(stream)));
 281 }
 282
 283 void Server::set_header(const string &stream_id, const string &header)
 284 {
 285         MutexLock lock(&mutex);
 286         find_stream(stream_id)->header = header;
 287
 288         // If there are clients we haven't sent anything to yet, we should give
 289         // them the header, so push back into the SENDING_HEADER state.
 290         for (map<int, Client>::iterator client_it = clients.begin();
 291              client_it != clients.end();
 292              ++client_it) {
 293                 Client *client = &client_it->second;
 294                 if (client->state == Client::SENDING_DATA &&
 295                     client->bytes_sent == 0) {
 296                         construct_header(client);
 297                 }
 298         }
 299 }
 300
 301 void Server::add_data(const string &stream_id, const char *data, size_t bytes)
 302 {
 303         if (bytes == 0) {
 304                 return;
 305         }
 306
 307         MutexLock lock(&mutex);
 308         Stream *stream = find_stream(stream_id);
 309         size_t pos = stream->data_size % BACKLOG_SIZE;
 310         stream->data_size += bytes;
 311
 312         if (pos + bytes > BACKLOG_SIZE) {
 313                 size_t to_copy = BACKLOG_SIZE - pos;
 314                 memcpy(stream->data + pos, data, to_copy);
 315                 data += to_copy;
 316                 bytes -= to_copy;
 317                 pos = 0;
 318         }
 319
 320         memcpy(stream->data + pos, data, bytes);
 321         stream->wake_up_all_clients();
 322 }
 323
 324 // See the .h file for postconditions after this function.
 325 void Server::process_client(Client *client)
 326 {
 327         switch (client->state) {
 328         case Client::READING_REQUEST: {
 329 read_request_again:
 330                 // Try to read more of the request.
 331                 char buf[1024];
 332                 int ret;
 333                 do {
 334                         ret = read(client->sock, buf, sizeof(buf));
 335                 } while (ret == -1 && errno == EINTR);
 336
 337                 if (ret == -1 && errno == EAGAIN) {
 338                         // No more data right now. Nothing to do.
 339                         // This is postcondition #2.
 340                         return;
 341                 }
 342                 if (ret == -1) {
 343                         perror("read");
 344                         close_client(client);
 345                         return;
 346                 }
 347                 if (ret == 0) {
 348                         // OK, the socket is closed.
 349                         close_client(client);
 350                         return;
 351                 }
 352
 353                 // Guard against overlong requests gobbling up all of our space.
 354                 if (client->request.size() + ret > MAX_CLIENT_REQUEST) {
 355                         fprintf(stderr, "WARNING: fd %d sent overlong request!\n", client->sock);
 356                         close_client(client);
 357                         return;
 358                 }
 359
 360                 // See if we have \r\n\r\n anywhere in the request. We start three bytes
 361                 // before what we just appended, in case we just got the final character.
 362                 size_t existing_req_bytes = client->request.size();
 363                 client->request.append(string(buf, buf + ret));
 364
 365                 size_t start_at = (existing_req_bytes >= 3 ? existing_req_bytes - 3 : 0);
 366                 const char *ptr = reinterpret_cast<char *>(
 367                         memmem(client->request.data() + start_at, client->request.size() - start_at,
 368                                "\r\n\r\n", 4));
 369                 if (ptr == NULL) {
 370                         // OK, we don't have the entire header yet. Fine; we'll get it later.
 371                         // See if there's more data for us.
 372                         goto read_request_again;
 373                 }
 374
 375                 if (ptr != client->request.data() + client->request.size() - 4) {
 376                         fprintf(stderr, "WARNING: fd %d had junk data after request!\n", client->sock);
 377                         close_client(client);
 378                         return;
 379                 }
 380
 381                 int error_code = parse_request(client);
 382                 if (error_code == 200) {
 383                         construct_header(client);
 384                 } else {
 385                         construct_error(client, error_code);
 386                 }
 387
 388                 // We've changed states, so fall through.
 389                 assert(client->state == Client::SENDING_ERROR ||
 390                        client->state == Client::SENDING_HEADER);
 391         }
 392         case Client::SENDING_ERROR:
 393         case Client::SENDING_HEADER: {
 394 sending_header_or_error_again:
 395                 int ret;
 396                 do {
 397                         ret = write(client->sock,
 398                                     client->header_or_error.data() + client->header_or_error_bytes_sent,
 399                                     client->header_or_error.size() - client->header_or_error_bytes_sent);
 400                 } while (ret == -1 && errno == EINTR);
 401
 402                 if (ret == -1 && errno == EAGAIN) {
 403                         // We're out of socket space, so now we're at the “low edge” of epoll's
 404                         // edge triggering. epoll will tell us when there is more room, so for now,
 405                         // just return.
 406                         // This is postcondition #4.
 407                         return;
 408                 }
 409
 410                 if (ret == -1) {
 411                         // Error! Postcondition #1.
 412                         perror("write");
 413                         close_client(client);
 414                         return;
 415                 }
 416
 417                 client->header_or_error_bytes_sent += ret;
 418                 assert(client->header_or_error_bytes_sent <= client->header_or_error.size());
 419
 420                 if (client->header_or_error_bytes_sent < client->header_or_error.size()) {
 421                         // We haven't sent all yet. Fine; go another round.
 422                         goto sending_header_or_error_again;
 423                 }
 424
 425                 // We're done sending the header or error! Clear it to release some memory.
 426                 client->header_or_error.clear();
 427
 428                 if (client->state == Client::SENDING_ERROR) {
 429                         // We're done sending the error, so now close.
 430                         // This is postcondition #1.
 431                         close_client(client);
 432                         return;
 433                 }
 434
 435                 // Start sending from the end. In other words, we won't send any of the backlog,
 436                 // but we'll start sending immediately as we get data.
 437                 // This is postcondition #3.
 438                 client->state = Client::SENDING_DATA;
 439                 client->bytes_sent = client->stream->data_size;
 440                 client->stream->put_client_to_sleep(client);
 441                 return;
 442         }
 443         case Client::SENDING_DATA: {
 444                 // See if there's some data we've lost. Ideally, we should drop to a block boundary,
 445                 // but resync will be the mux's problem.
 446                 Stream *stream = client->stream;
 447                 size_t bytes_to_send = stream->data_size - client->bytes_sent;
 448                 if (bytes_to_send == 0) {
 449                         return;
 450                 }
 451                 if (bytes_to_send > BACKLOG_SIZE) {
 452                         fprintf(stderr, "WARNING: fd %d lost %lld bytes, maybe too slow connection\n",
 453                                 client->sock,
 454                                 (long long int)(bytes_to_send - BACKLOG_SIZE));
 455                         client->bytes_sent = stream->data_size - BACKLOG_SIZE;
 456                         bytes_to_send = BACKLOG_SIZE;
 457                 }
 458
 459                 // See if we need to split across the circular buffer.
 460                 ssize_t ret;
 461                 if ((client->bytes_sent % BACKLOG_SIZE) + bytes_to_send > BACKLOG_SIZE) {
 462                         size_t bytes_first_part = BACKLOG_SIZE - (client->bytes_sent % BACKLOG_SIZE);
 463
 464                         iovec iov[2];
 465                         iov[0].iov_base = const_cast<char *>(stream->data + (client->bytes_sent % BACKLOG_SIZE));
 466                         iov[0].iov_len = bytes_first_part;
 467
 468                         iov[1].iov_base = const_cast<char *>(stream->data);
 469                         iov[1].iov_len = bytes_to_send - bytes_first_part;
 470
 471                         do {
 472                                 ret = writev(client->sock, iov, 2);
 473                         } while (ret == -1 && errno == EINTR);
 474                 } else {
 475                         do {
 476                                 ret = write(client->sock,
 477                                             stream->data + (client->bytes_sent % BACKLOG_SIZE),
 478                                             bytes_to_send);
 479                         } while (ret == -1 && errno == EINTR);
 480                 }
 481                 if (ret == -1 && errno == EAGAIN) {
 482                         // We're out of socket space, so return; epoll will wake us up
 483                         // when there is more room.
 484                         // This is postcondition #4.
 485                         return;
 486                 }
 487                 if (ret == -1) {
 488                         // Error, close; postcondition #1.
 489                         perror("write/writev");
 490                         close_client(client);
 491                         return;
 492                 }
 493                 client->bytes_sent += ret;
 494
 495                 if (client->bytes_sent == stream->data_size) {
 496                         // We don't have any more data for this client, so put it to sleep.
 497                         // This is postcondition #3.
 498                         stream->put_client_to_sleep(client);
 499                 } else {
 500                         // XXX: Do we need to go another round here to explicitly
 501                         // get the EAGAIN?
 502                 }
 503                 break;
 504         }
 505         default:
 506                 assert(false);
 507         }
 508 }
 509
 510 int Server::parse_request(Client *client)
 511 {
 512         vector<string> lines = split_lines(client->request);
 513         if (lines.empty()) {
 514                 return 400;  // Bad request (empty).
 515         }
 516
 517         vector<string> request_tokens = split_tokens(lines[0]);
 518         if (request_tokens.size() < 2) {
 519                 return 400;  // Bad request (empty).
 520         }
 521         if (request_tokens[0] != "GET") {
 522                 return 400;  // Should maybe be 405 instead?
 523         }
 524         if (streams.count(request_tokens[1]) == 0) {
 525                 return 404;  // Not found.
 526         }
 527
 528         client->stream_id = request_tokens[1];
 529         client->stream = find_stream(client->stream_id);
 530         client->request.clear();
 531
 532         return 200;  // OK!
 533 }
 534
 535 void Server::construct_header(Client *client)
 536 {
 537         client->header_or_error = "HTTP/1.0 200 OK\r\nContent-type: video/x-flv\r\nCache-Control: no-cache\r\n\r\n" +
 538                 find_stream(client->stream_id)->header;
 539
 540         // Switch states.
 541         client->state = Client::SENDING_HEADER;
 542
 543         epoll_event ev;
 544         ev.events = EPOLLOUT | EPOLLET | EPOLLRDHUP;
 545         ev.data.u64 = 0;  // Keep Valgrind happy.
 546         ev.data.fd = client->sock;
 547
 548         if (epoll_ctl(epoll_fd, EPOLL_CTL_MOD, client->sock, &ev) == -1) {
 549                 perror("epoll_ctl(EPOLL_CTL_MOD)");
 550                 exit(1);
 551         }
 552 }
 553
 554 void Server::construct_error(Client *client, int error_code)
 555 {
 556         char error[256];
 557         snprintf(error, 256, "HTTP/1.0 %d Error\r\nContent-type: text/plain\r\n\r\nSomething went wrong. Sorry.\r\n",
 558                 error_code);
 559         client->header_or_error = error;
 560
 561         // Switch states.
 562         client->state = Client::SENDING_ERROR;
 563
 564         epoll_event ev;
 565         ev.events = EPOLLOUT | EPOLLET | EPOLLRDHUP;
 566         ev.data.u64 = 0;  // Keep Valgrind happy.
 567         ev.data.fd = client->sock;
 568
 569         if (epoll_ctl(epoll_fd, EPOLL_CTL_MOD, client->sock, &ev) == -1) {
 570                 perror("epoll_ctl(EPOLL_CTL_MOD)");
 571                 exit(1);
 572         }
 573 }
 574
 575 void Server::close_client(Client *client)
 576 {
 577         if (epoll_ctl(epoll_fd, EPOLL_CTL_DEL, client->sock, NULL) == -1) {
 578                 perror("epoll_ctl(EPOLL_CTL_DEL)");
 579                 exit(1);
 580         }
 581
 582         // This client could be sleeping, so we'll need to fix that. (Argh, O(n).)
 583         if (client->stream != NULL) {
 584                 vector<Client *>::iterator new_end =
 585                         remove(client->stream->sleeping_clients.begin(),
 586                                client->stream->sleeping_clients.end(),
 587                                client);
 588                 client->stream->sleeping_clients.erase(
 589                         new_end, client->stream->sleeping_clients.end());
 590         }
 591
 592         // Bye-bye!
 593         int ret;
 594         do {
 595                 ret = close(client->sock);
 596         } while (ret == -1 && errno == EINTR);
 597
 598         if (ret == -1) {
 599                 perror("close");
 600         }
 601
 602         clients.erase(client->sock);
 603 }
 604
 605 Stream *Server::find_stream(const string &stream_id)
 606 {
 607         map<string, Stream *>::iterator it = streams.find(stream_id);
 608         assert(it != streams.end());
 609         return it->second;
 610 }