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