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 | EPOLLET | 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         process_client(&clients[sock]);
 213 }
 214
 215 void Server::add_client_from_serialized(const ClientProto &client)
 216 {
 217         MutexLock lock(&mutex);
 218         Stream *stream = find_stream(client.stream_id());
 219         clients.insert(make_pair(client.sock(), Client(client, stream)));
 220
 221         // Start listening on data from this socket.
 222         epoll_event ev;
 223         if (client.state() == Client::READING_REQUEST) {
 224                 ev.events = EPOLLIN | EPOLLET | EPOLLRDHUP;
 225         } else {
 226                 // If we don't have more data for this client, we'll be putting it into
 227                 // the sleeping array again soon.
 228                 ev.events = EPOLLOUT | EPOLLET | EPOLLRDHUP;
 229         }
 230         ev.data.u64 = 0;  // Keep Valgrind happy.
 231         ev.data.fd = client.sock();
 232         if (epoll_ctl(epoll_fd, EPOLL_CTL_ADD, client.sock(), &ev) == -1) {
 233                 perror("epoll_ctl(EPOLL_CTL_ADD)");
 234                 exit(1);
 235         }
 236
 237         process_client(&clients[client.sock()]);
 238 }
 239
 240 void Server::add_stream(const string &stream_id)
 241 {
 242         MutexLock lock(&mutex);
 243         streams.insert(make_pair(stream_id, new Stream(stream_id)));
 244 }
 245
 246 void Server::add_stream_from_serialized(const StreamProto &stream)
 247 {
 248         MutexLock lock(&mutex);
 249         streams.insert(make_pair(stream.stream_id(), new Stream(stream)));
 250 }
 251
 252 void Server::set_header(const string &stream_id, const string &header)
 253 {
 254         MutexLock lock(&mutex);
 255         find_stream(stream_id)->header = header;
 256
 257         // If there are clients we haven't sent anything to yet, we should give
 258         // them the header, so push back into the SENDING_HEADER state.
 259         for (map<int, Client>::iterator client_it = clients.begin();
 260              client_it != clients.end();
 261              ++client_it) {
 262                 Client *client = &client_it->second;
 263                 if (client->state == Client::SENDING_DATA &&
 264                     client->bytes_sent == 0) {
 265                         construct_header(client);
 266                 }
 267         }
 268 }
 269
 270 void Server::add_data(const string &stream_id, const char *data, size_t bytes)
 271 {
 272         if (bytes == 0) {
 273                 return;
 274         }
 275
 276         MutexLock lock(&mutex);
 277         Stream *stream = find_stream(stream_id);
 278         size_t pos = stream->data_size % BACKLOG_SIZE;
 279         stream->data_size += bytes;
 280
 281         if (pos + bytes > BACKLOG_SIZE) {
 282                 size_t to_copy = BACKLOG_SIZE - pos;
 283                 memcpy(stream->data + pos, data, to_copy);
 284                 data += to_copy;
 285                 bytes -= to_copy;
 286                 pos = 0;
 287         }
 288
 289         memcpy(stream->data + pos, data, bytes);
 290         wake_up_all_clients();
 291 }
 292
 293 // See the .h file for postconditions after this function.
 294 void Server::process_client(Client *client)
 295 {
 296         switch (client->state) {
 297         case Client::READING_REQUEST: {
 298 read_request_again:
 299                 // Try to read more of the request.
 300                 char buf[1024];
 301                 int ret;
 302                 do {
 303                         ret = read(client->sock, buf, sizeof(buf));
 304                 } while (ret == -1 && errno == EINTR);
 305
 306                 if (ret == -1 && errno == EAGAIN) {
 307                         // No more data right now. Nothing to do.
 308                         // This is postcondition #2.
 309                         return;
 310                 }
 311                 if (ret == -1) {
 312                         perror("read");
 313                         close_client(client);
 314                         return;
 315                 }
 316                 if (ret == 0) {
 317                         // OK, the socket is closed.
 318                         close_client(client);
 319                         return;
 320                 }
 321
 322                 // Guard against overlong requests gobbling up all of our space.
 323                 if (client->request.size() + ret > MAX_CLIENT_REQUEST) {
 324                         fprintf(stderr, "WARNING: fd %d sent overlong request!\n", client->sock);
 325                         close_client(client);
 326                         return;
 327                 }
 328
 329                 // See if we have \r\n\r\n anywhere in the request. We start three bytes
 330                 // before what we just appended, in case we just got the final character.
 331                 size_t existing_req_bytes = client->request.size();
 332                 client->request.append(string(buf, buf + ret));
 333
 334                 size_t start_at = (existing_req_bytes >= 3 ? existing_req_bytes - 3 : 0);
 335                 const char *ptr = reinterpret_cast<char *>(
 336                         memmem(client->request.data() + start_at, client->request.size() - start_at,
 337                                "\r\n\r\n", 4));
 338                 if (ptr == NULL) {
 339                         // OK, we don't have the entire header yet. Fine; we'll get it later.
 340                         // See if there's more data for us.
 341                         goto read_request_again;
 342                 }
 343
 344                 if (ptr != client->request.data() + client->request.size() - 4) {
 345                         fprintf(stderr, "WARNING: fd %d had junk data after request!\n", client->sock);
 346                         close_client(client);
 347                         return;
 348                 }
 349
 350                 int error_code = parse_request(client);
 351                 if (error_code == 200) {
 352                         construct_header(client);
 353                 } else {
 354                         construct_error(client, error_code);
 355                 }
 356
 357                 // We've changed states, so fall through.
 358                 assert(client->state == Client::SENDING_ERROR ||
 359                        client->state == Client::SENDING_HEADER);
 360         }
 361         case Client::SENDING_ERROR:
 362         case Client::SENDING_HEADER: {
 363 sending_header_or_error_again:
 364                 int ret;
 365                 do {
 366                         ret = write(client->sock,
 367                                     client->header_or_error.data() + client->header_or_error_bytes_sent,
 368                                     client->header_or_error.size() - client->header_or_error_bytes_sent);
 369                 } while (ret == -1 && errno == EINTR);
 370
 371                 if (ret == -1 && errno == EAGAIN) {
 372                         // We're out of socket space, so now we're at the “low edge” of epoll's
 373                         // edge triggering. epoll will tell us when there is more room, so for now,
 374                         // just return.
 375                         // This is postcondition #4.
 376                         return;
 377                 }
 378
 379                 if (ret == -1) {
 380                         // Error! Postcondition #1.
 381                         perror("write");
 382                         close_client(client);
 383                         return;
 384                 }
 385
 386                 client->header_or_error_bytes_sent += ret;
 387                 assert(client->header_or_error_bytes_sent <= client->header_or_error.size());
 388
 389                 if (client->header_or_error_bytes_sent < client->header_or_error.size()) {
 390                         // We haven't sent all yet. Fine; go another round.
 391                         goto sending_header_or_error_again;
 392                 }
 393
 394                 // We're done sending the header or error! Clear it to release some memory.
 395                 client->header_or_error.clear();
 396
 397                 if (client->state == Client::SENDING_ERROR) {
 398                         // We're done sending the error, so now close.
 399                         // This is postcondition #1.
 400                         close_client(client);
 401                         return;
 402                 }
 403
 404                 // Start sending from the end. In other words, we won't send any of the backlog,
 405                 // but we'll start sending immediately as we get data.
 406                 // This is postcondition #3.
 407                 client->state = Client::SENDING_DATA;
 408                 client->bytes_sent = client->stream->data_size;
 409                 put_client_to_sleep(client);
 410                 return;
 411         }
 412         case Client::SENDING_DATA: {
 413                 // See if there's some data we've lost. Ideally, we should drop to a block boundary,
 414                 // but resync will be the mux's problem.
 415                 const Stream *stream = client->stream;
 416                 size_t bytes_to_send = stream->data_size - client->bytes_sent;
 417                 if (bytes_to_send == 0) {
 418                         return;
 419                 }
 420                 if (bytes_to_send > BACKLOG_SIZE) {
 421                         fprintf(stderr, "WARNING: fd %d lost %lld bytes, maybe too slow connection\n",
 422                                 client->sock,
 423                                 (long long int)(bytes_to_send - BACKLOG_SIZE));
 424                         client->bytes_sent = stream->data_size - BACKLOG_SIZE;
 425                         bytes_to_send = BACKLOG_SIZE;
 426                 }
 427
 428                 // See if we need to split across the circular buffer.
 429                 ssize_t ret;
 430                 if ((client->bytes_sent % BACKLOG_SIZE) + bytes_to_send > BACKLOG_SIZE) {
 431                         size_t bytes_first_part = BACKLOG_SIZE - (client->bytes_sent % BACKLOG_SIZE);
 432
 433                         iovec iov[2];
 434                         iov[0].iov_base = const_cast<char *>(stream->data + (client->bytes_sent % BACKLOG_SIZE));
 435                         iov[0].iov_len = bytes_first_part;
 436
 437                         iov[1].iov_base = const_cast<char *>(stream->data);
 438                         iov[1].iov_len = bytes_to_send - bytes_first_part;
 439
 440                         do {
 441                                 ret = writev(client->sock, iov, 2);
 442                         } while (ret == -1 && errno == EINTR);
 443                 } else {
 444                         do {
 445                                 ret = write(client->sock,
 446                                             stream->data + (client->bytes_sent % BACKLOG_SIZE),
 447                                             bytes_to_send);
 448                         } while (ret == -1 && errno == EINTR);
 449                 }
 450                 if (ret == -1 && errno == EAGAIN) {
 451                         // We're out of socket space, so return; epoll will wake us up
 452                         // when there is more room.
 453                         // This is postcondition #4.
 454                         return;
 455                 }
 456                 if (ret == -1) {
 457                         // Error, close; postcondition #1.
 458                         perror("write/writev");
 459                         close_client(client);
 460                         return;
 461                 }
 462                 client->bytes_sent += ret;
 463
 464                 if (client->bytes_sent == stream->data_size) {
 465                         // We don't have any more data for this client, so put it to sleep.
 466                         // This is postcondition #3.
 467                         put_client_to_sleep(client);
 468                 } else {
 469                         // XXX: Do we need to go another round here to explicitly
 470                         // get the EAGAIN?
 471                 }
 472                 break;
 473         }
 474         default:
 475                 assert(false);
 476         }
 477 }
 478
 479 int Server::parse_request(Client *client)
 480 {
 481         vector<string> lines = split_lines(client->request);
 482         if (lines.empty()) {
 483                 return 400;  // Bad request (empty).
 484         }
 485
 486         vector<string> request_tokens = split_tokens(lines[0]);
 487         if (request_tokens.size() < 2) {
 488                 return 400;  // Bad request (empty).
 489         }
 490         if (request_tokens[0] != "GET") {
 491                 return 400;  // Should maybe be 405 instead?
 492         }
 493         if (streams.count(request_tokens[1]) == 0) {
 494                 return 404;  // Not found.
 495         }
 496
 497         client->stream_id = request_tokens[1];
 498         client->stream = find_stream(client->stream_id);
 499         client->request.clear();
 500
 501         return 200;  // OK!
 502 }
 503
 504 void Server::construct_header(Client *client)
 505 {
 506         client->header_or_error = "HTTP/1.0 200 OK\r\nContent-type: video/x-flv\r\nCache-Control: no-cache\r\n\r\n" +
 507                 find_stream(client->stream_id)->header;
 508
 509         // Switch states.
 510         client->state = Client::SENDING_HEADER;
 511
 512         epoll_event ev;
 513         ev.events = EPOLLOUT | EPOLLET | EPOLLRDHUP;
 514         ev.data.u64 = 0;  // Keep Valgrind happy.
 515         ev.data.fd = client->sock;
 516
 517         if (epoll_ctl(epoll_fd, EPOLL_CTL_MOD, client->sock, &ev) == -1) {
 518                 perror("epoll_ctl(EPOLL_CTL_MOD)");
 519                 exit(1);
 520         }
 521 }
 522
 523 void Server::construct_error(Client *client, int error_code)
 524 {
 525         char error[256];
 526         snprintf(error, 256, "HTTP/1.0 %d Error\r\nContent-type: text/plain\r\n\r\nSomething went wrong. Sorry.\r\n",
 527                 error_code);
 528         client->header_or_error = error;
 529
 530         // Switch states.
 531         client->state = Client::SENDING_ERROR;
 532
 533         epoll_event ev;
 534         ev.events = EPOLLOUT | EPOLLET | EPOLLRDHUP;
 535         ev.data.u64 = 0;  // Keep Valgrind happy.
 536         ev.data.fd = client->sock;
 537
 538         if (epoll_ctl(epoll_fd, EPOLL_CTL_MOD, client->sock, &ev) == -1) {
 539                 perror("epoll_ctl(EPOLL_CTL_MOD)");
 540                 exit(1);
 541         }
 542 }
 543
 544 void Server::close_client(Client *client)
 545 {
 546         if (epoll_ctl(epoll_fd, EPOLL_CTL_DEL, client->sock, NULL) == -1) {
 547                 perror("epoll_ctl(EPOLL_CTL_DEL)");
 548                 exit(1);
 549         }
 550
 551         // This client could be sleeping, so we'll need to fix that. (Argh, O(n).)
 552         vector<Client *>::iterator new_end =
 553                 remove(sleeping_clients.begin(), sleeping_clients.end(), client);
 554         sleeping_clients.erase(new_end, sleeping_clients.end());
 555
 556         // Bye-bye!
 557         int ret;
 558         do {
 559                 ret = close(client->sock);
 560         } while (ret == -1 && errno == EINTR);
 561
 562         if (ret == -1) {
 563                 perror("close");
 564         }
 565
 566         clients.erase(client->sock);
 567 }
 568
 569 void Server::put_client_to_sleep(Client *client)
 570 {
 571         sleeping_clients.push_back(client);
 572 }
 573
 574 void Server::wake_up_all_clients()
 575 {
 576         vector<Client *> to_process;
 577         swap(sleeping_clients, to_process);
 578         for (unsigned i = 0; i < to_process.size(); ++i) {
 579                 process_client(to_process[i]);
 580         }
 581 }
 582
 583 Stream *Server::find_stream(const string &stream_id)
 584 {
 585         map<string, Stream *>::iterator it = streams.find(stream_id);
 586         assert(it != streams.end());
 587         return it->second;
 588 }