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