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