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         for (map<string, Stream *>::iterator stream_it = streams.begin();
  45              stream_it != streams.end();
  46              ++stream_it) {
  47                 delete stream_it->second;
  48         }
  49
  50         int ret;
  51         do {
  52                 ret = close(epoll_fd);
  53         } while (ret == -1 && errno == EINTR);
  54
  55         if (ret == -1) {
  56                 log_perror("close(epoll_fd)");
  57         }
  58 }
  59
  60 vector<ClientStats> Server::get_client_stats() const
  61 {
  62         vector<ClientStats> ret;
  63
  64         MutexLock lock(&mutex);
  65         for (map<int, Client>::const_iterator client_it = clients.begin();
  66              client_it != clients.end();
  67              ++client_it) {
  68                 ret.push_back(client_it->second.get_stats());
  69         }
  70         return ret;
  71 }
  72
  73 void Server::do_work()
  74 {
  75         for ( ;; ) {
  76                 int nfds = epoll_wait(epoll_fd, events, EPOLL_MAX_EVENTS, EPOLL_TIMEOUT_MS);
  77                 if (nfds == -1 && errno == EINTR) {
  78                         if (should_stop) {
  79                                 return;
  80                         }
  81                         continue;
  82                 }
  83                 if (nfds == -1) {
  84                         log_perror("epoll_wait");
  85                         exit(1);
  86                 }
  87
  88                 MutexLock lock(&mutex);  // We release the mutex between iterations.
  89
  90                 process_queued_data();
  91
  92                 for (int i = 0; i < nfds; ++i) {
  93                         Client *client = reinterpret_cast<Client *>(events[i].data.u64);
  94
  95                         if (events[i].events & (EPOLLERR | EPOLLRDHUP | EPOLLHUP)) {
  96                                 close_client(client);
  97                                 continue;
  98                         }
  99
 100                         process_client(client);
 101                 }
 102
 103                 for (map<string, Stream *>::iterator stream_it = streams.begin();
 104                      stream_it != streams.end();
 105                      ++stream_it) {
 106                         vector<Client *> to_process;
 107                         swap(stream_it->second->to_process, to_process);
 108                         for (size_t i = 0; i < to_process.size(); ++i) {
 109                                 process_client(to_process[i]);
 110                         }
 111                 }
 112
 113                 if (should_stop) {
 114                         return;
 115                 }
 116         }
 117 }
 118
 119 CubemapStateProto Server::serialize()
 120 {
 121         // We don't serialize anything queued, so empty the queues.
 122         process_queued_data();
 123
 124         CubemapStateProto serialized;
 125         for (map<int, Client>::const_iterator client_it = clients.begin();
 126              client_it != clients.end();
 127              ++client_it) {
 128                 serialized.add_clients()->MergeFrom(client_it->second.serialize());
 129         }
 130         for (map<string, Stream *>::const_iterator stream_it = streams.begin();
 131              stream_it != streams.end();
 132              ++stream_it) {
 133                 serialized.add_streams()->MergeFrom(stream_it->second->serialize());
 134         }
 135         return serialized;
 136 }
 137
 138 void Server::add_client_deferred(int sock)
 139 {
 140         MutexLock lock(&queued_data_mutex);
 141         queued_add_clients.push_back(sock);
 142 }
 143
 144 void Server::add_client(int sock)
 145 {
 146         clients.insert(make_pair(sock, Client(sock)));
 147
 148         // Start listening on data from this socket.
 149         epoll_event ev;
 150         ev.events = EPOLLIN | EPOLLET | EPOLLRDHUP;
 151         ev.data.u64 = reinterpret_cast<uint64_t>(&clients[sock]);
 152         if (epoll_ctl(epoll_fd, EPOLL_CTL_ADD, sock, &ev) == -1) {
 153                 log_perror("epoll_ctl(EPOLL_CTL_ADD)");
 154                 exit(1);
 155         }
 156
 157         process_client(&clients[sock]);
 158 }
 159
 160 void Server::add_client_from_serialized(const ClientProto &client)
 161 {
 162         MutexLock lock(&mutex);
 163         Stream *stream;
 164         map<string, Stream *>::iterator stream_it = streams.find(client.stream_id());
 165         if (stream_it == streams.end()) {
 166                 stream = NULL;
 167         } else {
 168                 stream = stream_it->second;
 169         }
 170         clients.insert(make_pair(client.sock(), Client(client, stream)));
 171         Client *client_ptr = &clients[client.sock()];
 172
 173         // Start listening on data from this socket.
 174         epoll_event ev;
 175         if (client.state() == Client::READING_REQUEST) {
 176                 ev.events = EPOLLIN | EPOLLET | EPOLLRDHUP;
 177         } else {
 178                 // If we don't have more data for this client, we'll be putting it into
 179                 // the sleeping array again soon.
 180                 ev.events = EPOLLOUT | EPOLLET | EPOLLRDHUP;
 181         }
 182         ev.data.u64 = 0;  // Keep Valgrind happy.
 183         ev.data.u64 = reinterpret_cast<uint64_t>(client_ptr);
 184         if (epoll_ctl(epoll_fd, EPOLL_CTL_ADD, client.sock(), &ev) == -1) {
 185                 log_perror("epoll_ctl(EPOLL_CTL_ADD)");
 186                 exit(1);
 187         }
 188
 189         if (client_ptr->state == Client::SENDING_DATA &&
 190             client_ptr->stream_pos == client_ptr->stream->bytes_received) {
 191                 client_ptr->stream->put_client_to_sleep(client_ptr);
 192         } else {
 193                 process_client(client_ptr);
 194         }
 195 }
 196
 197 void Server::add_stream(const string &stream_id, size_t backlog_size)
 198 {
 199         MutexLock lock(&mutex);
 200         streams.insert(make_pair(stream_id, new Stream(stream_id, backlog_size)));
 201 }
 202
 203 void Server::add_stream_from_serialized(const StreamProto &stream)
 204 {
 205         MutexLock lock(&mutex);
 206         streams.insert(make_pair(stream.stream_id(), new Stream(stream)));
 207 }
 208
 209 void Server::set_backlog_size(const std::string &stream_id, size_t new_size)
 210 {
 211         MutexLock lock(&mutex);
 212         assert(streams.count(stream_id) != 0);
 213         streams[stream_id]->set_backlog_size(new_size);
 214 }
 215
 216 void Server::set_header(const string &stream_id, const string &header)
 217 {
 218         MutexLock lock(&mutex);
 219         find_stream(stream_id)->header = header;
 220
 221         // If there are clients we haven't sent anything to yet, we should give
 222         // them the header, so push back into the SENDING_HEADER state.
 223         for (map<int, Client>::iterator client_it = clients.begin();
 224              client_it != clients.end();
 225              ++client_it) {
 226                 Client *client = &client_it->second;
 227                 if (client->state == Client::SENDING_DATA &&
 228                     client->stream_pos == 0) {
 229                         construct_header(client);
 230                 }
 231         }
 232 }
 233
 234 void Server::set_mark_pool(const std::string &stream_id, MarkPool *mark_pool)
 235 {
 236         MutexLock lock(&mutex);
 237         assert(clients.empty());
 238         find_stream(stream_id)->mark_pool = mark_pool;
 239 }
 240
 241 void Server::add_data_deferred(const string &stream_id, const char *data, size_t bytes)
 242 {
 243         MutexLock lock(&queued_data_mutex);
 244         queued_data[stream_id].append(string(data, data + bytes));
 245 }
 246
 247 // See the .h file for postconditions after this function.
 248 void Server::process_client(Client *client)
 249 {
 250         switch (client->state) {
 251         case Client::READING_REQUEST: {
 252 read_request_again:
 253                 // Try to read more of the request.
 254                 char buf[1024];
 255                 int ret;
 256                 do {
 257                         ret = read(client->sock, buf, sizeof(buf));
 258                 } while (ret == -1 && errno == EINTR);
 259
 260                 if (ret == -1 && errno == EAGAIN) {
 261                         // No more data right now. Nothing to do.
 262                         // This is postcondition #2.
 263                         return;
 264                 }
 265                 if (ret == -1) {
 266                         log_perror("read");
 267                         close_client(client);
 268                         return;
 269                 }
 270                 if (ret == 0) {
 271                         // OK, the socket is closed.
 272                         close_client(client);
 273                         return;
 274                 }
 275
 276                 RequestParseStatus status = wait_for_double_newline(&client->request, buf, ret);
 277
 278                 switch (status) {
 279                 case RP_OUT_OF_SPACE:
 280                         log(WARNING, "[%s] Client sent overlong request!", client->remote_addr.c_str());
 281                         close_client(client);
 282                         return;
 283                 case RP_NOT_FINISHED_YET:
 284                         // OK, we don't have the entire header yet. Fine; we'll get it later.
 285                         // See if there's more data for us.
 286                         goto read_request_again;
 287                 case RP_EXTRA_DATA:
 288                         log(WARNING, "[%s] Junk data after request!", client->remote_addr.c_str());
 289                         close_client(client);
 290                         return;
 291                 case RP_FINISHED:
 292                         break;
 293                 }
 294
 295                 assert(status == RP_FINISHED);
 296
 297                 int error_code = parse_request(client);
 298                 if (error_code == 200) {
 299                         construct_header(client);
 300                 } else {
 301                         construct_error(client, error_code);
 302                 }
 303
 304                 // We've changed states, so fall through.
 305                 assert(client->state == Client::SENDING_ERROR ||
 306                        client->state == Client::SENDING_HEADER);
 307         }
 308         case Client::SENDING_ERROR:
 309         case Client::SENDING_HEADER: {
 310 sending_header_or_error_again:
 311                 int ret;
 312                 do {
 313                         ret = write(client->sock,
 314                                     client->header_or_error.data() + client->header_or_error_bytes_sent,
 315                                     client->header_or_error.size() - client->header_or_error_bytes_sent);
 316                 } while (ret == -1 && errno == EINTR);
 317
 318                 if (ret == -1 && errno == EAGAIN) {
 319                         // We're out of socket space, so now we're at the “low edge” of epoll's
 320                         // edge triggering. epoll will tell us when there is more room, so for now,
 321                         // just return.
 322                         // This is postcondition #4.
 323                         return;
 324                 }
 325
 326                 if (ret == -1) {
 327                         // Error! Postcondition #1.
 328                         log_perror("write");
 329                         close_client(client);
 330                         return;
 331                 }
 332
 333                 client->header_or_error_bytes_sent += ret;
 334                 assert(client->header_or_error_bytes_sent <= client->header_or_error.size());
 335
 336                 if (client->header_or_error_bytes_sent < client->header_or_error.size()) {
 337                         // We haven't sent all yet. Fine; go another round.
 338                         goto sending_header_or_error_again;
 339                 }
 340
 341                 // We're done sending the header or error! Clear it to release some memory.
 342                 client->header_or_error.clear();
 343
 344                 if (client->state == Client::SENDING_ERROR) {
 345                         // We're done sending the error, so now close.
 346                         // This is postcondition #1.
 347                         close_client(client);
 348                         return;
 349                 }
 350
 351                 // Start sending from the end. In other words, we won't send any of the backlog,
 352                 // but we'll start sending immediately as we get data.
 353                 // This is postcondition #3.
 354                 client->state = Client::SENDING_DATA;
 355                 client->stream_pos = client->stream->bytes_received;
 356                 client->stream->put_client_to_sleep(client);
 357                 return;
 358         }
 359         case Client::SENDING_DATA: {
 360 sending_data_again:
 361                 // See if there's some data we've lost. Ideally, we should drop to a block boundary,
 362                 // but resync will be the mux's problem.
 363                 Stream *stream = client->stream;
 364                 size_t bytes_to_send = stream->bytes_received - client->stream_pos;
 365                 if (bytes_to_send == 0) {
 366                         return;
 367                 }
 368                 if (bytes_to_send > stream->backlog_size) {
 369                         log(WARNING, "[%s] Client lost %lld bytes, maybe too slow connection",
 370                                 client->remote_addr.c_str(),
 371                                 (long long int)(bytes_to_send - stream->backlog_size));
 372                         client->stream_pos = stream->bytes_received - stream->backlog_size;
 373                         client->bytes_lost += bytes_to_send - stream->backlog_size;
 374                         ++client->num_loss_events;
 375                         bytes_to_send = stream->backlog_size;
 376                 }
 377
 378                 // See if we need to split across the circular buffer.
 379                 bool more_data = false;
 380                 if ((client->stream_pos % stream->backlog_size) + bytes_to_send > stream->backlog_size) {
 381                         bytes_to_send = stream->backlog_size - (client->stream_pos % stream->backlog_size);
 382                         more_data = true;
 383                 }
 384
 385                 ssize_t ret;
 386                 do {
 387                         loff_t offset = client->stream_pos % stream->backlog_size;
 388                         ret = sendfile(client->sock, stream->data_fd, &offset, bytes_to_send);
 389                 } while (ret == -1 && errno == EINTR);
 390
 391                 if (ret == -1 && errno == EAGAIN) {
 392                         // We're out of socket space, so return; epoll will wake us up
 393                         // when there is more room.
 394                         // This is postcondition #4.
 395                         return;
 396                 }
 397                 if (ret == -1) {
 398                         // Error, close; postcondition #1.
 399                         log_perror("sendfile");
 400                         close_client(client);
 401                         return;
 402                 }
 403                 client->stream_pos += ret;
 404                 client->bytes_sent += ret;
 405
 406                 if (client->stream_pos == stream->bytes_received) {
 407                         // We don't have any more data for this client, so put it to sleep.
 408                         // This is postcondition #3.
 409                         stream->put_client_to_sleep(client);
 410                 } else if (more_data && size_t(ret) == bytes_to_send) {
 411                         goto sending_data_again;
 412                 }
 413                 break;
 414         }
 415         default:
 416                 assert(false);
 417         }
 418 }
 419
 420 int Server::parse_request(Client *client)
 421 {
 422         vector<string> lines = split_lines(client->request);
 423         if (lines.empty()) {
 424                 return 400;  // Bad request (empty).
 425         }
 426
 427         vector<string> request_tokens = split_tokens(lines[0]);
 428         if (request_tokens.size() < 2) {
 429                 return 400;  // Bad request (empty).
 430         }
 431         if (request_tokens[0] != "GET") {
 432                 return 400;  // Should maybe be 405 instead?
 433         }
 434         if (streams.count(request_tokens[1]) == 0) {
 435                 return 404;  // Not found.
 436         }
 437
 438         client->stream_id = request_tokens[1];
 439         client->stream = find_stream(client->stream_id);
 440         if (client->stream->mark_pool != NULL) {
 441                 client->fwmark = client->stream->mark_pool->get_mark();
 442         } else {
 443                 client->fwmark = 0;  // No mark.
 444         }
 445         if (setsockopt(client->sock, SOL_SOCKET, SO_MARK, &client->fwmark, sizeof(client->fwmark)) == -1) {
 446                 if (client->fwmark != 0) {
 447                         log_perror("setsockopt(SO_MARK)");
 448                 }
 449         }
 450         client->request.clear();
 451
 452         return 200;  // OK!
 453 }
 454
 455 void Server::construct_header(Client *client)
 456 {
 457         client->header_or_error = find_stream(client->stream_id)->header;
 458
 459         // Switch states.
 460         client->state = Client::SENDING_HEADER;
 461
 462         epoll_event ev;
 463         ev.events = EPOLLOUT | EPOLLET | EPOLLRDHUP;
 464         ev.data.u64 = reinterpret_cast<uint64_t>(client);
 465
 466         if (epoll_ctl(epoll_fd, EPOLL_CTL_MOD, client->sock, &ev) == -1) {
 467                 log_perror("epoll_ctl(EPOLL_CTL_MOD)");
 468                 exit(1);
 469         }
 470 }
 471
 472 void Server::construct_error(Client *client, int error_code)
 473 {
 474         char error[256];
 475         snprintf(error, 256, "HTTP/1.0 %d Error\r\nContent-type: text/plain\r\n\r\nSomething went wrong. Sorry.\r\n",
 476                 error_code);
 477         client->header_or_error = error;
 478
 479         // Switch states.
 480         client->state = Client::SENDING_ERROR;
 481
 482         epoll_event ev;
 483         ev.events = EPOLLOUT | EPOLLET | EPOLLRDHUP;
 484         ev.data.u64 = reinterpret_cast<uint64_t>(client);
 485
 486         if (epoll_ctl(epoll_fd, EPOLL_CTL_MOD, client->sock, &ev) == -1) {
 487                 log_perror("epoll_ctl(EPOLL_CTL_MOD)");
 488                 exit(1);
 489         }
 490 }
 491
 492 template<class T>
 493 void delete_from(vector<T> *v, T elem)
 494 {
 495         typename vector<T>::iterator new_end = remove(v->begin(), v->end(), elem);
 496         v->erase(new_end, v->end());
 497 }
 498
 499 void Server::close_client(Client *client)
 500 {
 501         if (epoll_ctl(epoll_fd, EPOLL_CTL_DEL, client->sock, NULL) == -1) {
 502                 log_perror("epoll_ctl(EPOLL_CTL_DEL)");
 503                 exit(1);
 504         }
 505
 506         // This client could be sleeping, so we'll need to fix that. (Argh, O(n).)
 507         if (client->stream != NULL) {
 508                 delete_from(&client->stream->sleeping_clients, client);
 509                 delete_from(&client->stream->to_process, client);
 510                 if (client->stream->mark_pool != NULL) {
 511                         int fwmark = client->fwmark;
 512                         client->stream->mark_pool->release_mark(fwmark);
 513                 }
 514         }
 515
 516         // Log to access_log.
 517         access_log->write(client->get_stats());
 518
 519         // Bye-bye!
 520         int ret;
 521         do {
 522                 ret = close(client->sock);
 523         } while (ret == -1 && errno == EINTR);
 524
 525         if (ret == -1) {
 526                 log_perror("close");
 527         }
 528
 529         clients.erase(client->sock);
 530 }
 531
 532 Stream *Server::find_stream(const string &stream_id)
 533 {
 534         map<string, Stream *>::iterator it = streams.find(stream_id);
 535         assert(it != streams.end());
 536         return it->second;
 537 }
 538
 539 void Server::process_queued_data()
 540 {
 541         MutexLock lock(&queued_data_mutex);
 542
 543         for (size_t i = 0; i < queued_add_clients.size(); ++i) {
 544                 add_client(queued_add_clients[i]);
 545         }
 546         queued_add_clients.clear();
 547
 548         for (map<string, string>::iterator queued_it = queued_data.begin();
 549              queued_it != queued_data.end();
 550              ++queued_it) {
 551                 Stream *stream = find_stream(queued_it->first);
 552                 stream->add_data(queued_it->second.data(), queued_it->second.size());
 553                 stream->wake_up_all_clients();
 554         }
 555         queued_data.clear();
 556 }