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