git.sesse.net Git - cubemap/blob - server.cpp

   1 #include <assert.h>
   2 #include <errno.h>
   3 #include <pthread.h>
   4 #include <stdio.h>
   5 #include <stdlib.h>
   6 #include <sys/epoll.h>
   7 #include <sys/sendfile.h>
   8 #include <sys/socket.h>
   9 #include <sys/types.h>
  10 #include <unistd.h>
  11 #include <algorithm>
  12 #include <map>
  13 #include <string>
  14 #include <utility>
  15 #include <vector>
  16
  17 #include "markpool.h"
  18 #include "mutexlock.h"
  19 #include "parse.h"
  20 #include "server.h"
  21 #include "state.pb.h"
  22 #include "stream.h"
  23
  24 using namespace std;
  25
  26 Server::Server()
  27 {
  28         pthread_mutex_init(&mutex, NULL);
  29         pthread_mutex_init(&queued_data_mutex, NULL);
  30
  31         epoll_fd = epoll_create(1024);  // Size argument is ignored.
  32         if (epoll_fd == -1) {
  33                 perror("epoll_fd");
  34                 exit(1);
  35         }
  36 }
  37
  38 Server::~Server()
  39 {
  40         int ret;
  41         do {
  42                 ret = close(epoll_fd);
  43         } while (ret == -1 && errno == EINTR);
  44
  45         if (ret == -1) {
  46                 perror("close(epoll_fd)");
  47         }
  48 }
  49
  50 vector<ClientStats> Server::get_client_stats() const
  51 {
  52         vector<ClientStats> ret;
  53
  54         MutexLock lock(&mutex);
  55         for (map<int, Client>::const_iterator client_it = clients.begin();
  56              client_it != clients.end();
  57              ++client_it) {
  58                 ret.push_back(client_it->second.get_stats());
  59         }
  60         return ret;
  61 }
  62
  63 void Server::do_work()
  64 {
  65         for ( ;; ) {
  66                 int nfds = epoll_wait(epoll_fd, events, EPOLL_MAX_EVENTS, EPOLL_TIMEOUT_MS);
  67                 if (nfds == -1 && errno == EINTR) {
  68                         if (should_stop) {
  69                                 return;
  70                         }
  71                         continue;
  72                 }
  73                 if (nfds == -1) {
  74                         perror("epoll_wait");
  75                         exit(1);
  76                 }
  77
  78                 MutexLock lock(&mutex);  // We release the mutex between iterations.
  79
  80                 process_queued_data();
  81
  82                 for (int i = 0; i < nfds; ++i) {
  83                         int fd = events[i].data.fd;
  84                         assert(clients.count(fd) != 0);
  85                         Client *client = &clients[fd];
  86
  87                         if (events[i].events & (EPOLLERR | EPOLLRDHUP | EPOLLHUP)) {
  88                                 close_client(client);
  89                                 continue;
  90                         }
  91
  92                         process_client(client);
  93                 }
  94
  95                 for (map<string, Stream *>::iterator stream_it = streams.begin();
  96                      stream_it != streams.end();
  97                      ++stream_it) {
  98                         vector<Client *> to_process;
  99                         swap(stream_it->second->to_process, to_process);
 100                         for (size_t i = 0; i < to_process.size(); ++i) {
 101                                 process_client(to_process[i]);
 102                         }
 103                 }
 104
 105                 if (should_stop) {
 106                         return;
 107                 }
 108         }
 109 }
 110
 111 CubemapStateProto Server::serialize()
 112 {
 113         // We don't serialize anything queued, so empty the queues.
 114         process_queued_data();
 115
 116         CubemapStateProto serialized;
 117         for (map<int, Client>::const_iterator client_it = clients.begin();
 118              client_it != clients.end();
 119              ++client_it) {
 120                 serialized.add_clients()->MergeFrom(client_it->second.serialize());
 121         }
 122         for (map<string, Stream *>::const_iterator stream_it = streams.begin();
 123              stream_it != streams.end();
 124              ++stream_it) {
 125                 serialized.add_streams()->MergeFrom(stream_it->second->serialize());
 126         }
 127         return serialized;
 128 }
 129
 130 void Server::add_client_deferred(int sock)
 131 {
 132         MutexLock lock(&queued_data_mutex);
 133         queued_add_clients.push_back(sock);
 134 }
 135
 136 void Server::add_client(int sock)
 137 {
 138         clients.insert(make_pair(sock, Client(sock)));
 139
 140         // Start listening on data from this socket.
 141         epoll_event ev;
 142         ev.events = EPOLLIN | EPOLLET | EPOLLRDHUP;
 143         ev.data.u64 = 0;  // Keep Valgrind happy.
 144         ev.data.fd = sock;
 145         if (epoll_ctl(epoll_fd, EPOLL_CTL_ADD, sock, &ev) == -1) {
 146                 perror("epoll_ctl(EPOLL_CTL_ADD)");
 147                 exit(1);
 148         }
 149
 150         process_client(&clients[sock]);
 151 }
 152
 153 void Server::add_client_from_serialized(const ClientProto &client)
 154 {
 155         MutexLock lock(&mutex);
 156         Stream *stream;
 157         map<string, Stream *>::iterator stream_it = streams.find(client.stream_id());
 158         if (stream_it == streams.end()) {
 159                 stream = NULL;
 160         } else {
 161                 stream = stream_it->second;
 162         }
 163         clients.insert(make_pair(client.sock(), Client(client, stream)));
 164         Client *client_ptr = &clients[client.sock()];
 165
 166         // Start listening on data from this socket.
 167         epoll_event ev;
 168         if (client.state() == Client::READING_REQUEST) {
 169                 ev.events = EPOLLIN | EPOLLET | EPOLLRDHUP;
 170         } else {
 171                 // If we don't have more data for this client, we'll be putting it into
 172                 // the sleeping array again soon.
 173                 ev.events = EPOLLOUT | EPOLLET | EPOLLRDHUP;
 174         }
 175         ev.data.u64 = 0;  // Keep Valgrind happy.
 176         ev.data.fd = client.sock();
 177         if (epoll_ctl(epoll_fd, EPOLL_CTL_ADD, client.sock(), &ev) == -1) {
 178                 perror("epoll_ctl(EPOLL_CTL_ADD)");
 179                 exit(1);
 180         }
 181
 182         if (client_ptr->state == Client::SENDING_DATA &&
 183             client_ptr->stream_pos == client_ptr->stream->bytes_received) {
 184                 client_ptr->stream->put_client_to_sleep(client_ptr);
 185         } else {
 186                 process_client(client_ptr);
 187         }
 188 }
 189
 190 void Server::add_stream(const string &stream_id, size_t backlog_size)
 191 {
 192         MutexLock lock(&mutex);
 193         streams.insert(make_pair(stream_id, new Stream(stream_id, backlog_size)));
 194 }
 195
 196 void Server::add_stream_from_serialized(const StreamProto &stream)
 197 {
 198         MutexLock lock(&mutex);
 199         streams.insert(make_pair(stream.stream_id(), new Stream(stream)));
 200 }
 201
 202 void Server::set_backlog_size(const std::string &stream_id, size_t new_size)
 203 {
 204         MutexLock lock(&mutex);
 205         assert(streams.count(stream_id) != 0);
 206         streams[stream_id]->set_backlog_size(new_size);
 207 }
 208
 209 void Server::set_header(const string &stream_id, const string &header)
 210 {
 211         MutexLock lock(&mutex);
 212         find_stream(stream_id)->header = header;
 213
 214         // If there are clients we haven't sent anything to yet, we should give
 215         // them the header, so push back into the SENDING_HEADER state.
 216         for (map<int, Client>::iterator client_it = clients.begin();
 217              client_it != clients.end();
 218              ++client_it) {
 219                 Client *client = &client_it->second;
 220                 if (client->state == Client::SENDING_DATA &&
 221                     client->stream_pos == 0) {
 222                         construct_header(client);
 223                 }
 224         }
 225 }
 226
 227 void Server::set_mark_pool(const std::string &stream_id, MarkPool *mark_pool)
 228 {
 229         MutexLock lock(&mutex);
 230         assert(clients.empty());
 231         find_stream(stream_id)->mark_pool = mark_pool;
 232 }
 233
 234 void Server::add_data_deferred(const string &stream_id, const char *data, size_t bytes)
 235 {
 236         MutexLock lock(&queued_data_mutex);
 237         queued_data[stream_id].append(string(data, data + bytes));
 238 }
 239
 240 // See the .h file for postconditions after this function.
 241 void Server::process_client(Client *client)
 242 {
 243         switch (client->state) {
 244         case Client::READING_REQUEST: {
 245 read_request_again:
 246                 // Try to read more of the request.
 247                 char buf[1024];
 248                 int ret;
 249                 do {
 250                         ret = read(client->sock, buf, sizeof(buf));
 251                 } while (ret == -1 && errno == EINTR);
 252
 253                 if (ret == -1 && errno == EAGAIN) {
 254                         // No more data right now. Nothing to do.
 255                         // This is postcondition #2.
 256                         return;
 257                 }
 258                 if (ret == -1) {
 259                         perror("read");
 260                         close_client(client);
 261                         return;
 262                 }
 263                 if (ret == 0) {
 264                         // OK, the socket is closed.
 265                         close_client(client);
 266                         return;
 267                 }
 268
 269                 RequestParseStatus status = wait_for_double_newline(&client->request, buf, ret);
 270
 271                 switch (status) {
 272                 case RP_OUT_OF_SPACE:
 273                         fprintf(stderr, "WARNING: fd %d sent overlong request!\n", client->sock);
 274                         close_client(client);
 275                         return;
 276                 case RP_NOT_FINISHED_YET:
 277                         // OK, we don't have the entire header yet. Fine; we'll get it later.
 278                         // See if there's more data for us.
 279                         goto read_request_again;
 280                 case RP_EXTRA_DATA:
 281                         fprintf(stderr, "WARNING: fd %d had junk data after request!\n", client->sock);
 282                         close_client(client);
 283                         return;
 284                 case RP_FINISHED:
 285                         break;
 286                 }
 287
 288                 assert(status == RP_FINISHED);
 289
 290                 int error_code = parse_request(client);
 291                 if (error_code == 200) {
 292                         construct_header(client);
 293                 } else {
 294                         construct_error(client, error_code);
 295                 }
 296
 297                 // We've changed states, so fall through.
 298                 assert(client->state == Client::SENDING_ERROR ||
 299                        client->state == Client::SENDING_HEADER);
 300         }
 301         case Client::SENDING_ERROR:
 302         case Client::SENDING_HEADER: {
 303 sending_header_or_error_again:
 304                 int ret;
 305                 do {
 306                         ret = write(client->sock,
 307                                     client->header_or_error.data() + client->header_or_error_bytes_sent,
 308                                     client->header_or_error.size() - client->header_or_error_bytes_sent);
 309                 } while (ret == -1 && errno == EINTR);
 310
 311                 if (ret == -1 && errno == EAGAIN) {
 312                         // We're out of socket space, so now we're at the “low edge” of epoll's
 313                         // edge triggering. epoll will tell us when there is more room, so for now,
 314                         // just return.
 315                         // This is postcondition #4.
 316                         return;
 317                 }
 318
 319                 if (ret == -1) {
 320                         // Error! Postcondition #1.
 321                         perror("write");
 322                         close_client(client);
 323                         return;
 324                 }
 325
 326                 client->header_or_error_bytes_sent += ret;
 327                 assert(client->header_or_error_bytes_sent <= client->header_or_error.size());
 328
 329                 if (client->header_or_error_bytes_sent < client->header_or_error.size()) {
 330                         // We haven't sent all yet. Fine; go another round.
 331                         goto sending_header_or_error_again;
 332                 }
 333
 334                 // We're done sending the header or error! Clear it to release some memory.
 335                 client->header_or_error.clear();
 336
 337                 if (client->state == Client::SENDING_ERROR) {
 338                         // We're done sending the error, so now close.
 339                         // This is postcondition #1.
 340                         close_client(client);
 341                         return;
 342                 }
 343
 344                 // Start sending from the end. In other words, we won't send any of the backlog,
 345                 // but we'll start sending immediately as we get data.
 346                 // This is postcondition #3.
 347                 client->state = Client::SENDING_DATA;
 348                 client->stream_pos = client->stream->bytes_received;
 349                 client->stream->put_client_to_sleep(client);
 350                 return;
 351         }
 352         case Client::SENDING_DATA: {
 353 sending_data_again:
 354                 // See if there's some data we've lost. Ideally, we should drop to a block boundary,
 355                 // but resync will be the mux's problem.
 356                 Stream *stream = client->stream;
 357                 size_t bytes_to_send = stream->bytes_received - client->stream_pos;
 358                 if (bytes_to_send == 0) {
 359                         return;
 360                 }
 361                 if (bytes_to_send > stream->backlog_size) {
 362                         fprintf(stderr, "WARNING: fd %d lost %lld bytes, maybe too slow connection\n",
 363                                 client->sock,
 364                                 (long long int)(bytes_to_send - stream->backlog_size));
 365                         client->stream_pos = stream->bytes_received - stream->backlog_size;
 366                         client->bytes_lost += bytes_to_send - stream->backlog_size;
 367                         ++client->num_loss_events;
 368                         bytes_to_send = stream->backlog_size;
 369                 }
 370
 371                 // See if we need to split across the circular buffer.
 372                 bool more_data = false;
 373                 if ((client->stream_pos % stream->backlog_size) + bytes_to_send > stream->backlog_size) {
 374                         bytes_to_send = stream->backlog_size - (client->stream_pos % stream->backlog_size);
 375                         more_data = true;
 376                 }
 377
 378                 ssize_t ret;
 379                 do {
 380                         loff_t offset = client->stream_pos % stream->backlog_size;
 381                         ret = sendfile(client->sock, stream->data_fd, &offset, bytes_to_send);
 382                 } while (ret == -1 && errno == EINTR);
 383
 384                 if (ret == -1 && errno == EAGAIN) {
 385                         // We're out of socket space, so return; epoll will wake us up
 386                         // when there is more room.
 387                         // This is postcondition #4.
 388                         return;
 389                 }
 390                 if (ret == -1) {
 391                         // Error, close; postcondition #1.
 392                         perror("sendfile");
 393                         close_client(client);
 394                         return;
 395                 }
 396                 client->stream_pos += ret;
 397                 client->bytes_sent += ret;
 398
 399                 if (client->stream_pos == stream->bytes_received) {
 400                         // We don't have any more data for this client, so put it to sleep.
 401                         // This is postcondition #3.
 402                         stream->put_client_to_sleep(client);
 403                 } else if (more_data) {
 404                         goto sending_data_again;
 405                 }
 406                 break;
 407         }
 408         default:
 409                 assert(false);
 410         }
 411 }
 412
 413 int Server::parse_request(Client *client)
 414 {
 415         vector<string> lines = split_lines(client->request);
 416         if (lines.empty()) {
 417                 return 400;  // Bad request (empty).
 418         }
 419
 420         vector<string> request_tokens = split_tokens(lines[0]);
 421         if (request_tokens.size() < 2) {
 422                 return 400;  // Bad request (empty).
 423         }
 424         if (request_tokens[0] != "GET") {
 425                 return 400;  // Should maybe be 405 instead?
 426         }
 427         if (streams.count(request_tokens[1]) == 0) {
 428                 return 404;  // Not found.
 429         }
 430
 431         client->stream_id = request_tokens[1];
 432         client->stream = find_stream(client->stream_id);
 433         if (client->stream->mark_pool != NULL) {
 434                 client->fwmark = client->stream->mark_pool->get_mark();
 435         } else {
 436                 client->fwmark = 0;  // No mark.
 437         }
 438         if (setsockopt(client->sock, SOL_SOCKET, SO_MARK, &client->fwmark, sizeof(client->fwmark)) == -1) {
 439                 if (client->fwmark != 0) {
 440                         perror("setsockopt(SO_MARK)");
 441                 }
 442         }
 443         client->request.clear();
 444
 445         return 200;  // OK!
 446 }
 447
 448 void Server::construct_header(Client *client)
 449 {
 450         client->header_or_error = find_stream(client->stream_id)->header;
 451
 452         // Switch states.
 453         client->state = Client::SENDING_HEADER;
 454
 455         epoll_event ev;
 456         ev.events = EPOLLOUT | EPOLLET | EPOLLRDHUP;
 457         ev.data.u64 = 0;  // Keep Valgrind happy.
 458         ev.data.fd = client->sock;
 459
 460         if (epoll_ctl(epoll_fd, EPOLL_CTL_MOD, client->sock, &ev) == -1) {
 461                 perror("epoll_ctl(EPOLL_CTL_MOD)");
 462                 exit(1);
 463         }
 464 }
 465
 466 void Server::construct_error(Client *client, int error_code)
 467 {
 468         char error[256];
 469         snprintf(error, 256, "HTTP/1.0 %d Error\r\nContent-type: text/plain\r\n\r\nSomething went wrong. Sorry.\r\n",
 470                 error_code);
 471         client->header_or_error = error;
 472
 473         // Switch states.
 474         client->state = Client::SENDING_ERROR;
 475
 476         epoll_event ev;
 477         ev.events = EPOLLOUT | EPOLLET | EPOLLRDHUP;
 478         ev.data.u64 = 0;  // Keep Valgrind happy.
 479         ev.data.fd = client->sock;
 480
 481         if (epoll_ctl(epoll_fd, EPOLL_CTL_MOD, client->sock, &ev) == -1) {
 482                 perror("epoll_ctl(EPOLL_CTL_MOD)");
 483                 exit(1);
 484         }
 485 }
 486
 487 template<class T>
 488 void delete_from(vector<T> *v, T elem)
 489 {
 490         typename vector<T>::iterator new_end = remove(v->begin(), v->end(), elem);
 491         v->erase(new_end, v->end());
 492 }
 493
 494 void Server::close_client(Client *client)
 495 {
 496         if (epoll_ctl(epoll_fd, EPOLL_CTL_DEL, client->sock, NULL) == -1) {
 497                 perror("epoll_ctl(EPOLL_CTL_DEL)");
 498                 exit(1);
 499         }
 500
 501         // This client could be sleeping, so we'll need to fix that. (Argh, O(n).)
 502         if (client->stream != NULL) {
 503                 delete_from(&client->stream->sleeping_clients, client);
 504                 delete_from(&client->stream->to_process, client);
 505                 if (client->stream->mark_pool != NULL) {
 506                         int fwmark = client->fwmark;
 507                         client->stream->mark_pool->release_mark(fwmark);
 508                 }
 509         }
 510
 511         // Bye-bye!
 512         int ret;
 513         do {
 514                 ret = close(client->sock);
 515         } while (ret == -1 && errno == EINTR);
 516
 517         if (ret == -1) {
 518                 perror("close");
 519         }
 520
 521         clients.erase(client->sock);
 522 }
 523
 524 Stream *Server::find_stream(const string &stream_id)
 525 {
 526         map<string, Stream *>::iterator it = streams.find(stream_id);
 527         assert(it != streams.end());
 528         return it->second;
 529 }
 530
 531 void Server::process_queued_data()
 532 {
 533         MutexLock lock(&queued_data_mutex);
 534
 535         for (size_t i = 0; i < queued_add_clients.size(); ++i) {
 536                 add_client(queued_add_clients[i]);
 537         }
 538         queued_add_clients.clear();
 539
 540         for (map<string, string>::iterator queued_it = queued_data.begin();
 541              queued_it != queued_data.end();
 542              ++queued_it) {
 543                 Stream *stream = find_stream(queued_it->first);
 544                 stream->add_data(queued_it->second.data(), queued_it->second.size());
 545                 stream->wake_up_all_clients();
 546         }
 547         queued_data.clear();
 548 }