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 "accesslog.h"
  18 #include "log.h"
  19 #include "markpool.h"
  20 #include "mutexlock.h"
  21 #include "parse.h"
  22 #include "server.h"
  23 #include "state.pb.h"
  24 #include "stream.h"
  25
  26 using namespace std;
  27
  28 extern AccessLogThread *access_log;
  29
  30 Server::Server()
  31 {
  32         pthread_mutex_init(&mutex, NULL);
  33         pthread_mutex_init(&queued_data_mutex, NULL);
  34
  35         epoll_fd = epoll_create(1024);  // Size argument is ignored.
  36         if (epoll_fd == -1) {
  37                 log_perror("epoll_fd");
  38                 exit(1);
  39         }
  40 }
  41
  42 Server::~Server()
  43 {
  44         int ret;
  45         do {
  46                 ret = close(epoll_fd);
  47         } while (ret == -1 && errno == EINTR);
  48
  49         if (ret == -1) {
  50                 log_perror("close(epoll_fd)");
  51         }
  52 }
  53
  54 vector<ClientStats> Server::get_client_stats() const
  55 {
  56         vector<ClientStats> ret;
  57
  58         MutexLock lock(&mutex);
  59         for (map<int, Client>::const_iterator client_it = clients.begin();
  60              client_it != clients.end();
  61              ++client_it) {
  62                 ret.push_back(client_it->second.get_stats());
  63         }
  64         return ret;
  65 }
  66
  67 void Server::do_work()
  68 {
  69         for ( ;; ) {
  70                 int nfds = epoll_wait(epoll_fd, events, EPOLL_MAX_EVENTS, EPOLL_TIMEOUT_MS);
  71                 if (nfds == -1 && errno == EINTR) {
  72                         if (should_stop) {
  73                                 return;
  74                         }
  75                         continue;
  76                 }
  77                 if (nfds == -1) {
  78                         log_perror("epoll_wait");
  79                         exit(1);
  80                 }
  81
  82                 MutexLock lock(&mutex);  // We release the mutex between iterations.
  83
  84                 process_queued_data();
  85
  86                 for (int i = 0; i < nfds; ++i) {
  87                         Client *client = reinterpret_cast<Client *>(events[i].data.u64);
  88
  89                         if (events[i].events & (EPOLLERR | EPOLLRDHUP | EPOLLHUP)) {
  90                                 close_client(client);
  91                                 continue;
  92                         }
  93
  94                         process_client(client);
  95                 }
  96
  97                 for (map<string, Stream *>::iterator stream_it = streams.begin();
  98                      stream_it != streams.end();
  99                      ++stream_it) {
 100                         vector<Client *> to_process;
 101                         swap(stream_it->second->to_process, to_process);
 102                         for (size_t i = 0; i < to_process.size(); ++i) {
 103                                 process_client(to_process[i]);
 104                         }
 105                 }
 106
 107                 if (should_stop) {
 108                         return;
 109                 }
 110         }
 111 }
 112
 113 CubemapStateProto Server::serialize()
 114 {
 115         // We don't serialize anything queued, so empty the queues.
 116         process_queued_data();
 117
 118         CubemapStateProto serialized;
 119         for (map<int, Client>::const_iterator client_it = clients.begin();
 120              client_it != clients.end();
 121              ++client_it) {
 122                 serialized.add_clients()->MergeFrom(client_it->second.serialize());
 123         }
 124         for (map<string, Stream *>::const_iterator stream_it = streams.begin();
 125              stream_it != streams.end();
 126              ++stream_it) {
 127                 serialized.add_streams()->MergeFrom(stream_it->second->serialize());
 128         }
 129         return serialized;
 130 }
 131
 132 void Server::add_client_deferred(int sock)
 133 {
 134         MutexLock lock(&queued_data_mutex);
 135         queued_add_clients.push_back(sock);
 136 }
 137
 138 void Server::add_client(int sock)
 139 {
 140         clients.insert(make_pair(sock, Client(sock)));
 141
 142         // Start listening on data from this socket.
 143         epoll_event ev;
 144         ev.events = EPOLLIN | EPOLLET | EPOLLRDHUP;
 145         ev.data.u64 = reinterpret_cast<uint64_t>(&clients[sock]);
 146         if (epoll_ctl(epoll_fd, EPOLL_CTL_ADD, sock, &ev) == -1) {
 147                 log_perror("epoll_ctl(EPOLL_CTL_ADD)");
 148                 exit(1);
 149         }
 150
 151         process_client(&clients[sock]);
 152 }
 153
 154 void Server::add_client_from_serialized(const ClientProto &client)
 155 {
 156         MutexLock lock(&mutex);
 157         Stream *stream;
 158         map<string, Stream *>::iterator stream_it = streams.find(client.stream_id());
 159         if (stream_it == streams.end()) {
 160                 stream = NULL;
 161         } else {
 162                 stream = stream_it->second;
 163         }
 164         clients.insert(make_pair(client.sock(), Client(client, stream)));
 165         Client *client_ptr = &clients[client.sock()];
 166
 167         // Start listening on data from this socket.
 168         epoll_event ev;
 169         if (client.state() == Client::READING_REQUEST) {
 170                 ev.events = EPOLLIN | EPOLLET | EPOLLRDHUP;
 171         } else {
 172                 // If we don't have more data for this client, we'll be putting it into
 173                 // the sleeping array again soon.
 174                 ev.events = EPOLLOUT | EPOLLET | EPOLLRDHUP;
 175         }
 176         ev.data.u64 = 0;  // Keep Valgrind happy.
 177         ev.data.u64 = reinterpret_cast<uint64_t>(client_ptr);
 178         if (epoll_ctl(epoll_fd, EPOLL_CTL_ADD, client.sock(), &ev) == -1) {
 179                 log_perror("epoll_ctl(EPOLL_CTL_ADD)");
 180                 exit(1);
 181         }
 182
 183         if (client_ptr->state == Client::SENDING_DATA &&
 184             client_ptr->stream_pos == client_ptr->stream->bytes_received) {
 185                 client_ptr->stream->put_client_to_sleep(client_ptr);
 186         } else {
 187                 process_client(client_ptr);
 188         }
 189 }
 190
 191 void Server::add_stream(const string &stream_id, size_t backlog_size)
 192 {
 193         MutexLock lock(&mutex);
 194         streams.insert(make_pair(stream_id, new Stream(stream_id, backlog_size)));
 195 }
 196
 197 void Server::add_stream_from_serialized(const StreamProto &stream)
 198 {
 199         MutexLock lock(&mutex);
 200         streams.insert(make_pair(stream.stream_id(), new Stream(stream)));
 201 }
 202
 203 void Server::set_backlog_size(const std::string &stream_id, size_t new_size)
 204 {
 205         MutexLock lock(&mutex);
 206         assert(streams.count(stream_id) != 0);
 207         streams[stream_id]->set_backlog_size(new_size);
 208 }
 209
 210 void Server::set_header(const string &stream_id, const string &header)
 211 {
 212         MutexLock lock(&mutex);
 213         find_stream(stream_id)->header = header;
 214
 215         // If there are clients we haven't sent anything to yet, we should give
 216         // them the header, so push back into the SENDING_HEADER state.
 217         for (map<int, Client>::iterator client_it = clients.begin();
 218              client_it != clients.end();
 219              ++client_it) {
 220                 Client *client = &client_it->second;
 221                 if (client->state == Client::SENDING_DATA &&
 222                     client->stream_pos == 0) {
 223                         construct_header(client);
 224                 }
 225         }
 226 }
 227
 228 void Server::set_mark_pool(const std::string &stream_id, MarkPool *mark_pool)
 229 {
 230         MutexLock lock(&mutex);
 231         assert(clients.empty());
 232         find_stream(stream_id)->mark_pool = mark_pool;
 233 }
 234
 235 void Server::add_data_deferred(const string &stream_id, const char *data, size_t bytes)
 236 {
 237         MutexLock lock(&queued_data_mutex);
 238         queued_data[stream_id].append(string(data, data + bytes));
 239 }
 240
 241 // See the .h file for postconditions after this function.
 242 void Server::process_client(Client *client)
 243 {
 244         switch (client->state) {
 245         case Client::READING_REQUEST: {
 246 read_request_again:
 247                 // Try to read more of the request.
 248                 char buf[1024];
 249                 int ret;
 250                 do {
 251                         ret = read(client->sock, buf, sizeof(buf));
 252                 } while (ret == -1 && errno == EINTR);
 253
 254                 if (ret == -1 && errno == EAGAIN) {
 255                         // No more data right now. Nothing to do.
 256                         // This is postcondition #2.
 257                         return;
 258                 }
 259                 if (ret == -1) {
 260                         log_perror("read");
 261                         close_client(client);
 262                         return;
 263                 }
 264                 if (ret == 0) {
 265                         // OK, the socket is closed.
 266                         close_client(client);
 267                         return;
 268                 }
 269
 270                 RequestParseStatus status = wait_for_double_newline(&client->request, buf, ret);
 271
 272                 switch (status) {
 273                 case RP_OUT_OF_SPACE:
 274                         log(WARNING, "[%s] Client sent overlong request!", client->remote_addr.c_str());
 275                         close_client(client);
 276                         return;
 277                 case RP_NOT_FINISHED_YET:
 278                         // OK, we don't have the entire header yet. Fine; we'll get it later.
 279                         // See if there's more data for us.
 280                         goto read_request_again;
 281                 case RP_EXTRA_DATA:
 282                         log(WARNING, "[%s] Junk data after request!", client->remote_addr.c_str());
 283                         close_client(client);
 284                         return;
 285                 case RP_FINISHED:
 286                         break;
 287                 }
 288
 289                 assert(status == RP_FINISHED);
 290
 291                 int error_code = parse_request(client);
 292                 if (error_code == 200) {
 293                         construct_header(client);
 294                 } else {
 295                         construct_error(client, error_code);
 296                 }
 297
 298                 // We've changed states, so fall through.
 299                 assert(client->state == Client::SENDING_ERROR ||
 300                        client->state == Client::SENDING_HEADER);
 301         }
 302         case Client::SENDING_ERROR:
 303         case Client::SENDING_HEADER: {
 304 sending_header_or_error_again:
 305                 int ret;
 306                 do {
 307                         ret = write(client->sock,
 308                                     client->header_or_error.data() + client->header_or_error_bytes_sent,
 309                                     client->header_or_error.size() - client->header_or_error_bytes_sent);
 310                 } while (ret == -1 && errno == EINTR);
 311
 312                 if (ret == -1 && errno == EAGAIN) {
 313                         // We're out of socket space, so now we're at the “low edge” of epoll's
 314                         // edge triggering. epoll will tell us when there is more room, so for now,
 315                         // just return.
 316                         // This is postcondition #4.
 317                         return;
 318                 }
 319
 320                 if (ret == -1) {
 321                         // Error! Postcondition #1.
 322                         log_perror("write");
 323                         close_client(client);
 324                         return;
 325                 }
 326
 327                 client->header_or_error_bytes_sent += ret;
 328                 assert(client->header_or_error_bytes_sent <= client->header_or_error.size());
 329
 330                 if (client->header_or_error_bytes_sent < client->header_or_error.size()) {
 331                         // We haven't sent all yet. Fine; go another round.
 332                         goto sending_header_or_error_again;
 333                 }
 334
 335                 // We're done sending the header or error! Clear it to release some memory.
 336                 client->header_or_error.clear();
 337
 338                 if (client->state == Client::SENDING_ERROR) {
 339                         // We're done sending the error, so now close.
 340                         // This is postcondition #1.
 341                         close_client(client);
 342                         return;
 343                 }
 344
 345                 // Start sending from the end. In other words, we won't send any of the backlog,
 346                 // but we'll start sending immediately as we get data.
 347                 // This is postcondition #3.
 348                 client->state = Client::SENDING_DATA;
 349                 client->stream_pos = client->stream->bytes_received;
 350                 client->stream->put_client_to_sleep(client);
 351                 return;
 352         }
 353         case Client::SENDING_DATA: {
 354 sending_data_again:
 355                 // See if there's some data we've lost. Ideally, we should drop to a block boundary,
 356                 // but resync will be the mux's problem.
 357                 Stream *stream = client->stream;
 358                 size_t bytes_to_send = stream->bytes_received - client->stream_pos;
 359                 if (bytes_to_send == 0) {
 360                         return;
 361                 }
 362                 if (bytes_to_send > stream->backlog_size) {
 363                         log(WARNING, "[%s] Client lost %lld bytes, maybe too slow connection",
 364                                 client->remote_addr.c_str(),
 365                                 (long long int)(bytes_to_send - stream->backlog_size));
 366                         client->stream_pos = stream->bytes_received - stream->backlog_size;
 367                         client->bytes_lost += bytes_to_send - stream->backlog_size;
 368                         ++client->num_loss_events;
 369                         bytes_to_send = stream->backlog_size;
 370                 }
 371
 372                 // See if we need to split across the circular buffer.
 373                 bool more_data = false;
 374                 if ((client->stream_pos % stream->backlog_size) + bytes_to_send > stream->backlog_size) {
 375                         bytes_to_send = stream->backlog_size - (client->stream_pos % stream->backlog_size);
 376                         more_data = true;
 377                 }
 378
 379                 ssize_t ret;
 380                 do {
 381                         loff_t offset = client->stream_pos % stream->backlog_size;
 382                         ret = sendfile(client->sock, stream->data_fd, &offset, bytes_to_send);
 383                 } while (ret == -1 && errno == EINTR);
 384
 385                 if (ret == -1 && errno == EAGAIN) {
 386                         // We're out of socket space, so return; epoll will wake us up
 387                         // when there is more room.
 388                         // This is postcondition #4.
 389                         return;
 390                 }
 391                 if (ret == -1) {
 392                         // Error, close; postcondition #1.
 393                         log_perror("sendfile");
 394                         close_client(client);
 395                         return;
 396                 }
 397                 client->stream_pos += ret;
 398                 client->bytes_sent += ret;
 399
 400                 if (client->stream_pos == stream->bytes_received) {
 401                         // We don't have any more data for this client, so put it to sleep.
 402                         // This is postcondition #3.
 403                         stream->put_client_to_sleep(client);
 404                 } else if (more_data && size_t(ret) == bytes_to_send) {
 405                         goto sending_data_again;
 406                 }
 407                 break;
 408         }
 409         default:
 410                 assert(false);
 411         }
 412 }
 413
 414 int Server::parse_request(Client *client)
 415 {
 416         vector<string> lines = split_lines(client->request);
 417         if (lines.empty()) {
 418                 return 400;  // Bad request (empty).
 419         }
 420
 421         vector<string> request_tokens = split_tokens(lines[0]);
 422         if (request_tokens.size() < 2) {
 423                 return 400;  // Bad request (empty).
 424         }
 425         if (request_tokens[0] != "GET") {
 426                 return 400;  // Should maybe be 405 instead?
 427         }
 428         if (streams.count(request_tokens[1]) == 0) {
 429                 return 404;  // Not found.
 430         }
 431
 432         client->stream_id = request_tokens[1];
 433         client->stream = find_stream(client->stream_id);
 434         if (client->stream->mark_pool != NULL) {
 435                 client->fwmark = client->stream->mark_pool->get_mark();
 436         } else {
 437                 client->fwmark = 0;  // No mark.
 438         }
 439         if (setsockopt(client->sock, SOL_SOCKET, SO_MARK, &client->fwmark, sizeof(client->fwmark)) == -1) {
 440                 if (client->fwmark != 0) {
 441                         log_perror("setsockopt(SO_MARK)");
 442                 }
 443         }
 444         client->request.clear();
 445
 446         return 200;  // OK!
 447 }
 448
 449 void Server::construct_header(Client *client)
 450 {
 451         client->header_or_error = find_stream(client->stream_id)->header;
 452
 453         // Switch states.
 454         client->state = Client::SENDING_HEADER;
 455
 456         epoll_event ev;
 457         ev.events = EPOLLOUT | EPOLLET | EPOLLRDHUP;
 458         ev.data.u64 = reinterpret_cast<uint64_t>(client);
 459
 460         if (epoll_ctl(epoll_fd, EPOLL_CTL_MOD, client->sock, &ev) == -1) {
 461                 log_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 = reinterpret_cast<uint64_t>(client);
 479
 480         if (epoll_ctl(epoll_fd, EPOLL_CTL_MOD, client->sock, &ev) == -1) {
 481                 log_perror("epoll_ctl(EPOLL_CTL_MOD)");
 482                 exit(1);
 483         }
 484 }
 485
 486 template<class T>
 487 void delete_from(vector<T> *v, T elem)
 488 {
 489         typename vector<T>::iterator new_end = remove(v->begin(), v->end(), elem);
 490         v->erase(new_end, v->end());
 491 }
 492
 493 void Server::close_client(Client *client)
 494 {
 495         if (epoll_ctl(epoll_fd, EPOLL_CTL_DEL, client->sock, NULL) == -1) {
 496                 log_perror("epoll_ctl(EPOLL_CTL_DEL)");
 497                 exit(1);
 498         }
 499
 500         // This client could be sleeping, so we'll need to fix that. (Argh, O(n).)
 501         if (client->stream != NULL) {
 502                 delete_from(&client->stream->sleeping_clients, client);
 503                 delete_from(&client->stream->to_process, client);
 504                 if (client->stream->mark_pool != NULL) {
 505                         int fwmark = client->fwmark;
 506                         client->stream->mark_pool->release_mark(fwmark);
 507                 }
 508         }
 509
 510         // Log to access_log.
 511         access_log->write(client->get_stats());
 512
 513         // Bye-bye!
 514         int ret;
 515         do {
 516                 ret = close(client->sock);
 517         } while (ret == -1 && errno == EINTR);
 518
 519         if (ret == -1) {
 520                 log_perror("close");
 521         }
 522
 523         clients.erase(client->sock);
 524 }
 525
 526 Stream *Server::find_stream(const string &stream_id)
 527 {
 528         map<string, Stream *>::iterator it = streams.find(stream_id);
 529         assert(it != streams.end());
 530         return it->second;
 531 }
 532
 533 void Server::process_queued_data()
 534 {
 535         MutexLock lock(&queued_data_mutex);
 536
 537         for (size_t i = 0; i < queued_add_clients.size(); ++i) {
 538                 add_client(queued_add_clients[i]);
 539         }
 540         queued_add_clients.clear();
 541
 542         for (map<string, string>::iterator queued_it = queued_data.begin();
 543              queued_it != queued_data.end();
 544              ++queued_it) {
 545                 Stream *stream = find_stream(queued_it->first);
 546                 stream->add_data(queued_it->second.data(), queued_it->second.size());
 547                 stream->wake_up_all_clients();
 548         }
 549         queued_data.clear();
 550 }