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
 236 void Server::add_stream(const string &stream_id)
 237 {
 238         MutexLock lock(&mutex);
 239         streams.insert(make_pair(stream_id, new Stream(stream_id)));
 240 }
 241
 242 void Server::add_stream_from_serialized(const StreamProto &stream)
 243 {
 244         MutexLock lock(&mutex);
 245         streams.insert(make_pair(stream.stream_id(), new Stream(stream)));
 246 }
 247
 248 void Server::set_header(const string &stream_id, const string &header)
 249 {
 250         MutexLock lock(&mutex);
 251         find_stream(stream_id)->header = header;
 252
 253         // If there are clients we haven't sent anything to yet, we should give
 254         // them the header, so push back into the SENDING_HEADER state.
 255         for (map<int, Client>::iterator client_it = clients.begin();
 256              client_it != clients.end();
 257              ++client_it) {
 258                 Client *client = &client_it->second;
 259                 if (client->state == Client::SENDING_DATA &&
 260                     client->bytes_sent == 0) {
 261                         construct_header(client);
 262                 }
 263         }
 264 }
 265
 266 void Server::add_data(const string &stream_id, const char *data, size_t bytes)
 267 {
 268         if (bytes == 0) {
 269                 return;
 270         }
 271
 272         MutexLock lock(&mutex);
 273         Stream *stream = find_stream(stream_id);
 274         size_t pos = stream->data_size % BACKLOG_SIZE;
 275         stream->data_size += bytes;
 276
 277         if (pos + bytes > BACKLOG_SIZE) {
 278                 size_t to_copy = BACKLOG_SIZE - pos;
 279                 memcpy(stream->data + pos, data, to_copy);
 280                 data += to_copy;
 281                 bytes -= to_copy;
 282                 pos = 0;
 283         }
 284
 285         memcpy(stream->data + pos, data, bytes);
 286         wake_up_all_clients();
 287 }
 288
 289 // See the .h file for postconditions after this function.
 290 void Server::process_client(Client *client)
 291 {
 292         switch (client->state) {
 293         case Client::READING_REQUEST: {
 294 read_request_again:
 295                 // Try to read more of the request.
 296                 char buf[1024];
 297                 int ret;
 298                 do {
 299                         ret = read(client->sock, buf, sizeof(buf));
 300                 } while (ret == -1 && errno == EINTR);
 301
 302                 if (ret == -1 && errno == EAGAIN) {
 303                         // No more data right now. Nothing to do.
 304                         // This is postcondition #2.
 305                         return;
 306                 }
 307                 if (ret == -1) {
 308                         perror("read");
 309                         close_client(client);
 310                         return;
 311                 }
 312                 if (ret == 0) {
 313                         // OK, the socket is closed.
 314                         close_client(client);
 315                         return;
 316                 }
 317
 318                 // Guard against overlong requests gobbling up all of our space.
 319                 if (client->request.size() + ret > MAX_CLIENT_REQUEST) {
 320                         fprintf(stderr, "WARNING: fd %d sent overlong request!\n", client->sock);
 321                         close_client(client);
 322                         return;
 323                 }
 324
 325                 // See if we have \r\n\r\n anywhere in the request. We start three bytes
 326                 // before what we just appended, in case we just got the final character.
 327                 size_t existing_req_bytes = client->request.size();
 328                 client->request.append(string(buf, buf + ret));
 329
 330                 size_t start_at = (existing_req_bytes >= 3 ? existing_req_bytes - 3 : 0);
 331                 const char *ptr = reinterpret_cast<char *>(
 332                         memmem(client->request.data() + start_at, client->request.size() - start_at,
 333                                "\r\n\r\n", 4));
 334                 if (ptr == NULL) {
 335                         // OK, we don't have the entire header yet. Fine; we'll get it later.
 336                         // See if there's more data for us.
 337                         goto read_request_again;
 338                 }
 339
 340                 if (ptr != client->request.data() + client->request.size() - 4) {
 341                         fprintf(stderr, "WARNING: fd %d had junk data after request!\n", client->sock);
 342                         close_client(client);
 343                         return;
 344                 }
 345
 346                 int error_code = parse_request(client);
 347                 if (error_code == 200) {
 348                         construct_header(client);
 349                 } else {
 350                         construct_error(client, error_code);
 351                 }
 352
 353                 // We've changed states, so fall through.
 354                 assert(client->state == Client::SENDING_ERROR ||
 355                        client->state == Client::SENDING_HEADER);
 356         }
 357         case Client::SENDING_ERROR:
 358         case Client::SENDING_HEADER: {
 359 sending_header_or_error_again:
 360                 int ret;
 361                 do {
 362                         ret = write(client->sock,
 363                                     client->header_or_error.data() + client->header_or_error_bytes_sent,
 364                                     client->header_or_error.size() - client->header_or_error_bytes_sent);
 365                 } while (ret == -1 && errno == EINTR);
 366
 367                 if (ret == -1 && errno == EAGAIN) {
 368                         // We're out of socket space, so now we're at the “low edge” of epoll's
 369                         // edge triggering. epoll will tell us when there is more room, so for now,
 370                         // just return.
 371                         // This is postcondition #4.
 372                         return;
 373                 }
 374
 375                 if (ret == -1) {
 376                         // Error! Postcondition #1.
 377                         perror("write");
 378                         close_client(client);
 379                         return;
 380                 }
 381
 382                 client->header_or_error_bytes_sent += ret;
 383                 assert(client->header_or_error_bytes_sent <= client->header_or_error.size());
 384
 385                 if (client->header_or_error_bytes_sent < client->header_or_error.size()) {
 386                         // We haven't sent all yet. Fine; go another round.
 387                         goto sending_header_or_error_again;
 388                 }
 389
 390                 // We're done sending the header or error! Clear it to release some memory.
 391                 client->header_or_error.clear();
 392
 393                 if (client->state == Client::SENDING_ERROR) {
 394                         // We're done sending the error, so now close.
 395                         // This is postcondition #1.
 396                         close_client(client);
 397                         return;
 398                 }
 399
 400                 // Start sending from the end. In other words, we won't send any of the backlog,
 401                 // but we'll start sending immediately as we get data.
 402                 // This is postcondition #3.
 403                 client->state = Client::SENDING_DATA;
 404                 client->bytes_sent = client->stream->data_size;
 405                 sleeping_clients.push_back(client);
 406                 return;
 407         }
 408         case Client::SENDING_DATA: {
 409                 // See if there's some data we've lost. Ideally, we should drop to a block boundary,
 410                 // but resync will be the mux's problem.
 411                 const Stream *stream = client->stream;
 412                 size_t bytes_to_send = stream->data_size - client->bytes_sent;
 413                 if (bytes_to_send > BACKLOG_SIZE) {
 414                         fprintf(stderr, "WARNING: fd %d lost %lld bytes, maybe too slow connection\n",
 415                                 client->sock,
 416                                 (long long int)(bytes_to_send - BACKLOG_SIZE));
 417                         client->bytes_sent = stream->data_size - BACKLOG_SIZE;
 418                         bytes_to_send = BACKLOG_SIZE;
 419                 }
 420
 421                 // See if we need to split across the circular buffer.
 422                 ssize_t ret;
 423                 if ((client->bytes_sent % BACKLOG_SIZE) + bytes_to_send > BACKLOG_SIZE) {
 424                         size_t bytes_first_part = BACKLOG_SIZE - (client->bytes_sent % BACKLOG_SIZE);
 425
 426                         iovec iov[2];
 427                         iov[0].iov_base = const_cast<char *>(stream->data + (client->bytes_sent % BACKLOG_SIZE));
 428                         iov[0].iov_len = bytes_first_part;
 429
 430                         iov[1].iov_base = const_cast<char *>(stream->data);
 431                         iov[1].iov_len = bytes_to_send - bytes_first_part;
 432
 433                         do {
 434                                 ret = writev(client->sock, iov, 2);
 435                         } while (ret == -1 && errno == EINTR);
 436                 } else {
 437                         do {
 438                                 ret = write(client->sock,
 439                                             stream->data + (client->bytes_sent % BACKLOG_SIZE),
 440                                             bytes_to_send);
 441                         } while (ret == -1 && errno == EINTR);
 442                 }
 443                 if (ret == -1 && errno == EAGAIN) {
 444                         // We're out of socket space, so return; epoll will wake us up
 445                         // when there is more room.
 446                         // This is postcondition #4.
 447                         return;
 448                 }
 449                 if (ret == -1) {
 450                         // Error, close; postcondition #1.
 451                         perror("write/writev");
 452                         close_client(client);
 453                         return;
 454                 }
 455                 client->bytes_sent += ret;
 456
 457                 if (client->bytes_sent == stream->data_size) {
 458                         // We don't have any more data for this client, so put it to sleep.
 459                         // This is postcondition #3.
 460                         put_client_to_sleep(client);
 461                 } else {
 462                         // XXX: Do we need to go another round here to explicitly
 463                         // get the EAGAIN?
 464                 }
 465                 break;
 466         }
 467         default:
 468                 assert(false);
 469         }
 470 }
 471
 472 int Server::parse_request(Client *client)
 473 {
 474         vector<string> lines = split_lines(client->request);
 475         if (lines.empty()) {
 476                 return 400;  // Bad request (empty).
 477         }
 478
 479         vector<string> request_tokens = split_tokens(lines[0]);
 480         if (request_tokens.size() < 2) {
 481                 return 400;  // Bad request (empty).
 482         }
 483         if (request_tokens[0] != "GET") {
 484                 return 400;  // Should maybe be 405 instead?
 485         }
 486         if (streams.count(request_tokens[1]) == 0) {
 487                 return 404;  // Not found.
 488         }
 489
 490         client->stream_id = request_tokens[1];
 491         client->stream = streams[client->stream_id];
 492         client->request.clear();
 493
 494         return 200;  // OK!
 495 }
 496
 497 void Server::construct_header(Client *client)
 498 {
 499         client->header_or_error = "HTTP/1.0 200 OK\r\nContent-type: video/x-flv\r\nCache-Control: no-cache\r\n\r\n" +
 500                 find_stream(client->stream_id)->header;
 501
 502         // Switch states.
 503         client->state = Client::SENDING_HEADER;
 504
 505         epoll_event ev;
 506         ev.events = EPOLLOUT | EPOLLET | EPOLLRDHUP;
 507         ev.data.u64 = 0;  // Keep Valgrind happy.
 508         ev.data.fd = client->sock;
 509
 510         if (epoll_ctl(epoll_fd, EPOLL_CTL_MOD, client->sock, &ev) == -1) {
 511                 perror("epoll_ctl(EPOLL_CTL_MOD)");
 512                 exit(1);
 513         }
 514 }
 515
 516 void Server::construct_error(Client *client, int error_code)
 517 {
 518         char error[256];
 519         snprintf(error, 256, "HTTP/1.0 %d Error\r\nContent-type: text/plain\r\n\r\nSomething went wrong. Sorry.\r\n",
 520                 error_code);
 521         client->header_or_error = error;
 522
 523         // Switch states.
 524         client->state = Client::SENDING_ERROR;
 525
 526         epoll_event ev;
 527         ev.events = EPOLLOUT | EPOLLET | EPOLLRDHUP;
 528         ev.data.u64 = 0;  // Keep Valgrind happy.
 529         ev.data.fd = client->sock;
 530
 531         if (epoll_ctl(epoll_fd, EPOLL_CTL_MOD, client->sock, &ev) == -1) {
 532                 perror("epoll_ctl(EPOLL_CTL_MOD)");
 533                 exit(1);
 534         }
 535 }
 536
 537 void Server::close_client(Client *client)
 538 {
 539         if (epoll_ctl(epoll_fd, EPOLL_CTL_DEL, client->sock, NULL) == -1) {
 540                 perror("epoll_ctl(EPOLL_CTL_DEL)");
 541                 exit(1);
 542         }
 543
 544         // This client could be sleeping, so we'll need to fix that. (Argh, O(n).)
 545         vector<Client *>::iterator new_end =
 546                 remove(sleeping_clients.begin(), sleeping_clients.end(), client);
 547         sleeping_clients.erase(new_end, sleeping_clients.end());
 548
 549         // Bye-bye!
 550         int ret;
 551         do {
 552                 ret = close(client->sock);
 553         } while (ret == -1 && errno == EINTR);
 554
 555         if (ret == -1) {
 556                 perror("close");
 557         }
 558
 559         clients.erase(client->sock);
 560 }
 561
 562 void Server::put_client_to_sleep(Client *client)
 563 {
 564         sleeping_clients.push_back(client);
 565 }
 566
 567 void Server::wake_up_all_clients()
 568 {
 569         vector<Client *> to_process;
 570         swap(sleeping_clients, to_process);
 571         for (unsigned i = 0; i < to_process.size(); ++i) {
 572                 process_client(to_process[i]);
 573         }
 574 }
 575
 576 Stream *Server::find_stream(const string &stream_id)
 577 {
 578         map<string, Stream *>::iterator it = streams.find(stream_id);
 579         assert(it != streams.end());
 580         return it->second;
 581 }