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 = find_stream(client.stream_id());
 157         clients.insert(make_pair(client.sock(), Client(client, stream)));
 158         Client *client_ptr = &clients[client.sock()];
 159
 160         // Start listening on data from this socket.
 161         epoll_event ev;
 162         if (client.state() == Client::READING_REQUEST) {
 163                 ev.events = EPOLLIN | EPOLLET | EPOLLRDHUP;
 164         } else {
 165                 // If we don't have more data for this client, we'll be putting it into
 166                 // the sleeping array again soon.
 167                 ev.events = EPOLLOUT | EPOLLET | EPOLLRDHUP;
 168         }
 169         ev.data.u64 = 0;  // Keep Valgrind happy.
 170         ev.data.fd = client.sock();
 171         if (epoll_ctl(epoll_fd, EPOLL_CTL_ADD, client.sock(), &ev) == -1) {
 172                 perror("epoll_ctl(EPOLL_CTL_ADD)");
 173                 exit(1);
 174         }
 175
 176         if (client_ptr->state == Client::SENDING_DATA &&
 177             client_ptr->bytes_sent == client_ptr->stream->bytes_received) {
 178                 client_ptr->stream->put_client_to_sleep(client_ptr);
 179         } else {
 180                 process_client(client_ptr);
 181         }
 182 }
 183
 184 void Server::add_stream(const string &stream_id, size_t backlog_size)
 185 {
 186         MutexLock lock(&mutex);
 187         streams.insert(make_pair(stream_id, new Stream(stream_id, backlog_size)));
 188 }
 189
 190 void Server::add_stream_from_serialized(const StreamProto &stream)
 191 {
 192         MutexLock lock(&mutex);
 193         streams.insert(make_pair(stream.stream_id(), new Stream(stream)));
 194 }
 195
 196 void Server::set_backlog_size(const std::string &stream_id, size_t new_size)
 197 {
 198         MutexLock lock(&mutex);
 199         assert(streams.count(stream_id) != 0);
 200         streams[stream_id]->set_backlog_size(new_size);
 201 }
 202
 203 void Server::set_header(const string &stream_id, const string &header)
 204 {
 205         MutexLock lock(&mutex);
 206         find_stream(stream_id)->header = header;
 207
 208         // If there are clients we haven't sent anything to yet, we should give
 209         // them the header, so push back into the SENDING_HEADER state.
 210         for (map<int, Client>::iterator client_it = clients.begin();
 211              client_it != clients.end();
 212              ++client_it) {
 213                 Client *client = &client_it->second;
 214                 if (client->state == Client::SENDING_DATA &&
 215                     client->bytes_sent == 0) {
 216                         construct_header(client);
 217                 }
 218         }
 219 }
 220
 221 void Server::set_mark_pool(const std::string &stream_id, MarkPool *mark_pool)
 222 {
 223         MutexLock lock(&mutex);
 224         assert(clients.empty());
 225         find_stream(stream_id)->mark_pool = mark_pool;
 226 }
 227
 228 void Server::add_data_deferred(const string &stream_id, const char *data, size_t bytes)
 229 {
 230         MutexLock lock(&queued_data_mutex);
 231         queued_data[stream_id].append(string(data, data + bytes));
 232 }
 233
 234 // See the .h file for postconditions after this function.
 235 void Server::process_client(Client *client)
 236 {
 237         switch (client->state) {
 238         case Client::READING_REQUEST: {
 239 read_request_again:
 240                 // Try to read more of the request.
 241                 char buf[1024];
 242                 int ret;
 243                 do {
 244                         ret = read(client->sock, buf, sizeof(buf));
 245                 } while (ret == -1 && errno == EINTR);
 246
 247                 if (ret == -1 && errno == EAGAIN) {
 248                         // No more data right now. Nothing to do.
 249                         // This is postcondition #2.
 250                         return;
 251                 }
 252                 if (ret == -1) {
 253                         perror("read");
 254                         close_client(client);
 255                         return;
 256                 }
 257                 if (ret == 0) {
 258                         // OK, the socket is closed.
 259                         close_client(client);
 260                         return;
 261                 }
 262
 263                 RequestParseStatus status = wait_for_double_newline(&client->request, buf, ret);
 264
 265                 switch (status) {
 266                 case RP_OUT_OF_SPACE:
 267                         fprintf(stderr, "WARNING: fd %d sent overlong request!\n", client->sock);
 268                         close_client(client);
 269                         return;
 270                 case RP_NOT_FINISHED_YET:
 271                         // OK, we don't have the entire header yet. Fine; we'll get it later.
 272                         // See if there's more data for us.
 273                         goto read_request_again;
 274                 case RP_EXTRA_DATA:
 275                         fprintf(stderr, "WARNING: fd %d had junk data after request!\n", client->sock);
 276                         close_client(client);
 277                         return;
 278                 case RP_FINISHED:
 279                         break;
 280                 }
 281
 282                 assert(status == RP_FINISHED);
 283
 284                 int error_code = parse_request(client);
 285                 if (error_code == 200) {
 286                         construct_header(client);
 287                 } else {
 288                         construct_error(client, error_code);
 289                 }
 290
 291                 // We've changed states, so fall through.
 292                 assert(client->state == Client::SENDING_ERROR ||
 293                        client->state == Client::SENDING_HEADER);
 294         }
 295         case Client::SENDING_ERROR:
 296         case Client::SENDING_HEADER: {
 297 sending_header_or_error_again:
 298                 int ret;
 299                 do {
 300                         ret = write(client->sock,
 301                                     client->header_or_error.data() + client->header_or_error_bytes_sent,
 302                                     client->header_or_error.size() - client->header_or_error_bytes_sent);
 303                 } while (ret == -1 && errno == EINTR);
 304
 305                 if (ret == -1 && errno == EAGAIN) {
 306                         // We're out of socket space, so now we're at the “low edge” of epoll's
 307                         // edge triggering. epoll will tell us when there is more room, so for now,
 308                         // just return.
 309                         // This is postcondition #4.
 310                         return;
 311                 }
 312
 313                 if (ret == -1) {
 314                         // Error! Postcondition #1.
 315                         perror("write");
 316                         close_client(client);
 317                         return;
 318                 }
 319
 320                 client->header_or_error_bytes_sent += ret;
 321                 assert(client->header_or_error_bytes_sent <= client->header_or_error.size());
 322
 323                 if (client->header_or_error_bytes_sent < client->header_or_error.size()) {
 324                         // We haven't sent all yet. Fine; go another round.
 325                         goto sending_header_or_error_again;
 326                 }
 327
 328                 // We're done sending the header or error! Clear it to release some memory.
 329                 client->header_or_error.clear();
 330
 331                 if (client->state == Client::SENDING_ERROR) {
 332                         // We're done sending the error, so now close.
 333                         // This is postcondition #1.
 334                         close_client(client);
 335                         return;
 336                 }
 337
 338                 // Start sending from the end. In other words, we won't send any of the backlog,
 339                 // but we'll start sending immediately as we get data.
 340                 // This is postcondition #3.
 341                 client->state = Client::SENDING_DATA;
 342                 client->bytes_sent = client->stream->bytes_received;
 343                 client->stream->put_client_to_sleep(client);
 344                 return;
 345         }
 346         case Client::SENDING_DATA: {
 347 sending_data_again:
 348                 // See if there's some data we've lost. Ideally, we should drop to a block boundary,
 349                 // but resync will be the mux's problem.
 350                 Stream *stream = client->stream;
 351                 size_t bytes_to_send = stream->bytes_received - client->bytes_sent;
 352                 if (bytes_to_send == 0) {
 353                         return;
 354                 }
 355                 if (bytes_to_send > stream->backlog_size) {
 356                         fprintf(stderr, "WARNING: fd %d lost %lld bytes, maybe too slow connection\n",
 357                                 client->sock,
 358                                 (long long int)(bytes_to_send - stream->backlog_size));
 359                         client->bytes_sent = stream->bytes_received - stream->backlog_size;
 360                         bytes_to_send = stream->backlog_size;
 361                 }
 362
 363                 // See if we need to split across the circular buffer.
 364                 bool more_data = false;
 365                 if ((client->bytes_sent % stream->backlog_size) + bytes_to_send > stream->backlog_size) {
 366                         bytes_to_send = stream->backlog_size - (client->bytes_sent % stream->backlog_size);
 367                         more_data = true;
 368                 }
 369
 370                 ssize_t ret;
 371                 do {
 372                         loff_t offset = client->bytes_sent % stream->backlog_size;
 373                         ret = sendfile(client->sock, stream->data_fd, &offset, bytes_to_send);
 374                 } while (ret == -1 && errno == EINTR);
 375
 376                 if (ret == -1 && errno == EAGAIN) {
 377                         // We're out of socket space, so return; epoll will wake us up
 378                         // when there is more room.
 379                         // This is postcondition #4.
 380                         return;
 381                 }
 382                 if (ret == -1) {
 383                         // Error, close; postcondition #1.
 384                         perror("sendfile");
 385                         close_client(client);
 386                         return;
 387                 }
 388                 client->bytes_sent += ret;
 389
 390                 if (client->bytes_sent == stream->bytes_received) {
 391                         // We don't have any more data for this client, so put it to sleep.
 392                         // This is postcondition #3.
 393                         stream->put_client_to_sleep(client);
 394                 } else if (more_data) {
 395                         goto sending_data_again;
 396                 }
 397                 break;
 398         }
 399         default:
 400                 assert(false);
 401         }
 402 }
 403
 404 int Server::parse_request(Client *client)
 405 {
 406         vector<string> lines = split_lines(client->request);
 407         if (lines.empty()) {
 408                 return 400;  // Bad request (empty).
 409         }
 410
 411         vector<string> request_tokens = split_tokens(lines[0]);
 412         if (request_tokens.size() < 2) {
 413                 return 400;  // Bad request (empty).
 414         }
 415         if (request_tokens[0] != "GET") {
 416                 return 400;  // Should maybe be 405 instead?
 417         }
 418         if (streams.count(request_tokens[1]) == 0) {
 419                 return 404;  // Not found.
 420         }
 421
 422         client->stream_id = request_tokens[1];
 423         client->stream = find_stream(client->stream_id);
 424         if (client->stream->mark_pool != NULL) {
 425                 client->fwmark = client->stream->mark_pool->get_mark();
 426         } else {
 427                 client->fwmark = 0;  // No mark.
 428         }
 429         if (setsockopt(client->sock, SOL_SOCKET, SO_MARK, &client->fwmark, sizeof(client->fwmark)) == -1) {
 430                 if (client->fwmark != 0) {
 431                         perror("setsockopt(SO_MARK)");
 432                 }
 433         }
 434         client->request.clear();
 435
 436         return 200;  // OK!
 437 }
 438
 439 void Server::construct_header(Client *client)
 440 {
 441         client->header_or_error = find_stream(client->stream_id)->header;
 442
 443         // Switch states.
 444         client->state = Client::SENDING_HEADER;
 445
 446         epoll_event ev;
 447         ev.events = EPOLLOUT | EPOLLET | EPOLLRDHUP;
 448         ev.data.u64 = 0;  // Keep Valgrind happy.
 449         ev.data.fd = client->sock;
 450
 451         if (epoll_ctl(epoll_fd, EPOLL_CTL_MOD, client->sock, &ev) == -1) {
 452                 perror("epoll_ctl(EPOLL_CTL_MOD)");
 453                 exit(1);
 454         }
 455 }
 456
 457 void Server::construct_error(Client *client, int error_code)
 458 {
 459         char error[256];
 460         snprintf(error, 256, "HTTP/1.0 %d Error\r\nContent-type: text/plain\r\n\r\nSomething went wrong. Sorry.\r\n",
 461                 error_code);
 462         client->header_or_error = error;
 463
 464         // Switch states.
 465         client->state = Client::SENDING_ERROR;
 466
 467         epoll_event ev;
 468         ev.events = EPOLLOUT | EPOLLET | EPOLLRDHUP;
 469         ev.data.u64 = 0;  // Keep Valgrind happy.
 470         ev.data.fd = client->sock;
 471
 472         if (epoll_ctl(epoll_fd, EPOLL_CTL_MOD, client->sock, &ev) == -1) {
 473                 perror("epoll_ctl(EPOLL_CTL_MOD)");
 474                 exit(1);
 475         }
 476 }
 477
 478 template<class T>
 479 void delete_from(vector<T> *v, T elem)
 480 {
 481         typename vector<T>::iterator new_end = remove(v->begin(), v->end(), elem);
 482         v->erase(new_end, v->end());
 483 }
 484
 485 void Server::close_client(Client *client)
 486 {
 487         if (epoll_ctl(epoll_fd, EPOLL_CTL_DEL, client->sock, NULL) == -1) {
 488                 perror("epoll_ctl(EPOLL_CTL_DEL)");
 489                 exit(1);
 490         }
 491
 492         // This client could be sleeping, so we'll need to fix that. (Argh, O(n).)
 493         if (client->stream != NULL) {
 494                 delete_from(&client->stream->sleeping_clients, client);
 495                 delete_from(&client->stream->to_process, client);
 496                 if (client->stream->mark_pool != NULL) {
 497                         int fwmark = client->fwmark;
 498                         client->stream->mark_pool->release_mark(fwmark);
 499                 }
 500         }
 501
 502         // Bye-bye!
 503         int ret;
 504         do {
 505                 ret = close(client->sock);
 506         } while (ret == -1 && errno == EINTR);
 507
 508         if (ret == -1) {
 509                 perror("close");
 510         }
 511
 512         clients.erase(client->sock);
 513 }
 514
 515 Stream *Server::find_stream(const string &stream_id)
 516 {
 517         map<string, Stream *>::iterator it = streams.find(stream_id);
 518         assert(it != streams.end());
 519         return it->second;
 520 }
 521
 522 void Server::process_queued_data()
 523 {
 524         MutexLock lock(&queued_data_mutex);
 525
 526         for (size_t i = 0; i < queued_add_clients.size(); ++i) {
 527                 add_client(queued_add_clients[i]);
 528         }
 529         queued_add_clients.clear();
 530
 531         for (map<string, string>::iterator queued_it = queued_data.begin();
 532              queued_it != queued_data.end();
 533              ++queued_it) {
 534                 Stream *stream = find_stream(queued_it->first);
 535                 stream->add_data(queued_it->second.data(), queued_it->second.size());
 536                 stream->wake_up_all_clients();
 537         }
 538         queued_data.clear();
 539 }