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

   1 #include <assert.h>
   2 #include <errno.h>
   3 #include <netinet/in.h>
   4 #include <pthread.h>
   5 #include <stdint.h>
   6 #include <stdio.h>
   7 #include <stdlib.h>
   8 #include <string.h>
   9 #include <sys/epoll.h>
  10 #include <sys/sendfile.h>
  11 #include <sys/socket.h>
  12 #include <sys/types.h>
  13 #include <unistd.h>
  14 #include <algorithm>
  15 #include <map>
  16 #include <string>
  17 #include <utility>
  18 #include <vector>
  19
  20 #include "accesslog.h"
  21 #include "log.h"
  22 #include "markpool.h"
  23 #include "metacube.h"
  24 #include "mutexlock.h"
  25 #include "parse.h"
  26 #include "server.h"
  27 #include "state.pb.h"
  28 #include "stream.h"
  29 #include "util.h"
  30
  31 using namespace std;
  32
  33 extern AccessLogThread *access_log;
  34
  35 Server::Server()
  36 {
  37         pthread_mutex_init(&mutex, NULL);
  38         pthread_mutex_init(&queued_data_mutex, NULL);
  39
  40         epoll_fd = epoll_create(1024);  // Size argument is ignored.
  41         if (epoll_fd == -1) {
  42                 log_perror("epoll_fd");
  43                 exit(1);
  44         }
  45 }
  46
  47 Server::~Server()
  48 {
  49         for (size_t i = 0; i < streams.size(); ++i) {
  50                 delete streams[i];
  51         }
  52
  53         safe_close(epoll_fd);
  54 }
  55
  56 vector<ClientStats> Server::get_client_stats() const
  57 {
  58         vector<ClientStats> ret;
  59
  60         MutexLock lock(&mutex);
  61         for (map<int, Client>::const_iterator client_it = clients.begin();
  62              client_it != clients.end();
  63              ++client_it) {
  64                 ret.push_back(client_it->second.get_stats());
  65         }
  66         return ret;
  67 }
  68
  69 void Server::do_work()
  70 {
  71         while (!should_stop()) {
  72                 // Wait until there's activity on at least one of the fds,
  73                 // or 20 ms (about one frame at 50 fps) has elapsed.
  74                 //
  75                 // We could in theory wait forever and rely on wakeup()
  76                 // from add_client_deferred() and add_data_deferred(),
  77                 // but wakeup is a pretty expensive operation, and the
  78                 // two threads might end up fighting over a lock, so it's
  79                 // seemingly (much) more efficient to just have a timeout here.
  80                 int nfds = epoll_pwait(epoll_fd, events, EPOLL_MAX_EVENTS, EPOLL_TIMEOUT_MS, &sigset_without_usr1_block);
  81                 if (nfds == -1 && errno != EINTR) {
  82                         log_perror("epoll_wait");
  83                         exit(1);
  84                 }
  85
  86                 MutexLock lock(&mutex);  // We release the mutex between iterations.
  87
  88                 process_queued_data();
  89
  90                 for (int i = 0; i < nfds; ++i) {
  91                         Client *client = reinterpret_cast<Client *>(events[i].data.u64);
  92
  93                         if (events[i].events & (EPOLLERR | EPOLLRDHUP | EPOLLHUP)) {
  94                                 close_client(client);
  95                                 continue;
  96                         }
  97
  98                         process_client(client);
  99                 }
 100
 101                 for (size_t i = 0; i < streams.size(); ++i) {
 102                         vector<Client *> to_process;
 103                         swap(streams[i]->to_process, to_process);
 104                         for (size_t i = 0; i < to_process.size(); ++i) {
 105                                 process_client(to_process[i]);
 106                         }
 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 (size_t i = 0; i < streams.size(); ++i) {
 123                 serialized.add_streams()->MergeFrom(streams[i]->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         pair<map<int, Client>::iterator, bool> ret =
 137                 clients.insert(make_pair(sock, Client(sock)));
 138         assert(ret.second == true);  // Should not already exist.
 139         Client *client_ptr = &ret.first->second;
 140
 141         // Start listening on data from this socket.
 142         epoll_event ev;
 143         ev.events = EPOLLIN | EPOLLET | EPOLLRDHUP;
 144         ev.data.u64 = reinterpret_cast<uint64_t>(client_ptr);
 145         if (epoll_ctl(epoll_fd, EPOLL_CTL_ADD, sock, &ev) == -1) {
 146                 log_perror("epoll_ctl(EPOLL_CTL_ADD)");
 147                 exit(1);
 148         }
 149
 150         process_client(client_ptr);
 151 }
 152
 153 void Server::add_client_from_serialized(const ClientProto &client)
 154 {
 155         MutexLock lock(&mutex);
 156         Stream *stream;
 157         int stream_index = lookup_stream_by_url(client.url());
 158         if (stream_index == -1) {
 159                 assert(client.state() != Client::SENDING_DATA);
 160                 stream = NULL;
 161         } else {
 162                 stream = streams[stream_index];
 163         }
 164         pair<map<int, Client>::iterator, bool> ret =
 165                 clients.insert(make_pair(client.sock(), Client(client, stream)));
 166         assert(ret.second == true);  // Should not already exist.
 167         Client *client_ptr = &ret.first->second;
 168
 169         // Start listening on data from this socket.
 170         epoll_event ev;
 171         if (client.state() == Client::READING_REQUEST) {
 172                 ev.events = EPOLLIN | EPOLLET | EPOLLRDHUP;
 173         } else {
 174                 // If we don't have more data for this client, we'll be putting it into
 175                 // the sleeping array again soon.
 176                 ev.events = EPOLLOUT | EPOLLET | EPOLLRDHUP;
 177         }
 178         ev.data.u64 = reinterpret_cast<uint64_t>(client_ptr);
 179         if (epoll_ctl(epoll_fd, EPOLL_CTL_ADD, client.sock(), &ev) == -1) {
 180                 log_perror("epoll_ctl(EPOLL_CTL_ADD)");
 181                 exit(1);
 182         }
 183
 184         if (client_ptr->state == Client::SENDING_DATA &&
 185             client_ptr->stream_pos == client_ptr->stream->bytes_received) {
 186                 client_ptr->stream->put_client_to_sleep(client_ptr);
 187         } else {
 188                 process_client(client_ptr);
 189         }
 190 }
 191
 192 int Server::lookup_stream_by_url(const std::string &url) const
 193 {
 194         map<string, int>::const_iterator url_it = url_map.find(url);
 195         if (url_it == url_map.end()) {
 196                 return -1;
 197         }
 198         return url_it->second;
 199 }
 200
 201 int Server::add_stream(const string &url, size_t backlog_size, Stream::Encoding encoding)
 202 {
 203         MutexLock lock(&mutex);
 204         url_map.insert(make_pair(url, streams.size()));
 205         streams.push_back(new Stream(url, backlog_size, encoding));
 206         return streams.size() - 1;
 207 }
 208
 209 int Server::add_stream_from_serialized(const StreamProto &stream, int data_fd)
 210 {
 211         MutexLock lock(&mutex);
 212         url_map.insert(make_pair(stream.url(), streams.size()));
 213         streams.push_back(new Stream(stream, data_fd));
 214         return streams.size() - 1;
 215 }
 216
 217 void Server::set_backlog_size(int stream_index, size_t new_size)
 218 {
 219         MutexLock lock(&mutex);
 220         assert(stream_index >= 0 && stream_index < ssize_t(streams.size()));
 221         streams[stream_index]->set_backlog_size(new_size);
 222 }
 223
 224 void Server::set_encoding(int stream_index, Stream::Encoding encoding)
 225 {
 226         MutexLock lock(&mutex);
 227         assert(stream_index >= 0 && stream_index < ssize_t(streams.size()));
 228         streams[stream_index]->encoding = encoding;
 229 }
 230
 231 void Server::set_header(int stream_index, const string &http_header, const string &stream_header)
 232 {
 233         MutexLock lock(&mutex);
 234         assert(stream_index >= 0 && stream_index < ssize_t(streams.size()));
 235         streams[stream_index]->http_header = http_header;
 236         streams[stream_index]->stream_header = stream_header;
 237
 238         // If there are clients we haven't sent anything to yet, we should give
 239         // them the header, so push back into the SENDING_HEADER state.
 240         for (map<int, Client>::iterator client_it = clients.begin();
 241              client_it != clients.end();
 242              ++client_it) {
 243                 Client *client = &client_it->second;
 244                 if (client->state == Client::SENDING_DATA &&
 245                     client->stream_pos == 0) {
 246                         construct_header(client);
 247                 }
 248         }
 249 }
 250
 251 void Server::set_mark_pool(int stream_index, MarkPool *mark_pool)
 252 {
 253         MutexLock lock(&mutex);
 254         assert(clients.empty());
 255         assert(stream_index >= 0 && stream_index < ssize_t(streams.size()));
 256         streams[stream_index]->mark_pool = mark_pool;
 257 }
 258
 259 void Server::add_data_deferred(int stream_index, const char *data, size_t bytes)
 260 {
 261         MutexLock lock(&queued_data_mutex);
 262         assert(stream_index >= 0 && stream_index < ssize_t(streams.size()));
 263         streams[stream_index]->add_data_deferred(data, bytes);
 264 }
 265
 266 // See the .h file for postconditions after this function.
 267 void Server::process_client(Client *client)
 268 {
 269         switch (client->state) {
 270         case Client::READING_REQUEST: {
 271 read_request_again:
 272                 // Try to read more of the request.
 273                 char buf[1024];
 274                 int ret;
 275                 do {
 276                         ret = read(client->sock, buf, sizeof(buf));
 277                 } while (ret == -1 && errno == EINTR);
 278
 279                 if (ret == -1 && errno == EAGAIN) {
 280                         // No more data right now. Nothing to do.
 281                         // This is postcondition #2.
 282                         return;
 283                 }
 284                 if (ret == -1) {
 285                         log_perror("read");
 286                         close_client(client);
 287                         return;
 288                 }
 289                 if (ret == 0) {
 290                         // OK, the socket is closed.
 291                         close_client(client);
 292                         return;
 293                 }
 294
 295                 RequestParseStatus status = wait_for_double_newline(&client->request, buf, ret);
 296
 297                 switch (status) {
 298                 case RP_OUT_OF_SPACE:
 299                         log(WARNING, "[%s] Client sent overlong request!", client->remote_addr.c_str());
 300                         close_client(client);
 301                         return;
 302                 case RP_NOT_FINISHED_YET:
 303                         // OK, we don't have the entire header yet. Fine; we'll get it later.
 304                         // See if there's more data for us.
 305                         goto read_request_again;
 306                 case RP_EXTRA_DATA:
 307                         log(WARNING, "[%s] Junk data after request!", client->remote_addr.c_str());
 308                         close_client(client);
 309                         return;
 310                 case RP_FINISHED:
 311                         break;
 312                 }
 313
 314                 assert(status == RP_FINISHED);
 315
 316                 int error_code = parse_request(client);
 317                 if (error_code == 200) {
 318                         construct_header(client);
 319                 } else {
 320                         construct_error(client, error_code);
 321                 }
 322
 323                 // We've changed states, so fall through.
 324                 assert(client->state == Client::SENDING_ERROR ||
 325                        client->state == Client::SENDING_HEADER);
 326         }
 327         case Client::SENDING_ERROR:
 328         case Client::SENDING_HEADER: {
 329 sending_header_or_error_again:
 330                 int ret;
 331                 do {
 332                         ret = write(client->sock,
 333                                     client->header_or_error.data() + client->header_or_error_bytes_sent,
 334                                     client->header_or_error.size() - client->header_or_error_bytes_sent);
 335                 } while (ret == -1 && errno == EINTR);
 336
 337                 if (ret == -1 && errno == EAGAIN) {
 338                         // We're out of socket space, so now we're at the “low edge” of epoll's
 339                         // edge triggering. epoll will tell us when there is more room, so for now,
 340                         // just return.
 341                         // This is postcondition #4.
 342                         return;
 343                 }
 344
 345                 if (ret == -1) {
 346                         // Error! Postcondition #1.
 347                         log_perror("write");
 348                         close_client(client);
 349                         return;
 350                 }
 351
 352                 client->header_or_error_bytes_sent += ret;
 353                 assert(client->header_or_error_bytes_sent <= client->header_or_error.size());
 354
 355                 if (client->header_or_error_bytes_sent < client->header_or_error.size()) {
 356                         // We haven't sent all yet. Fine; go another round.
 357                         goto sending_header_or_error_again;
 358                 }
 359
 360                 // We're done sending the header or error! Clear it to release some memory.
 361                 client->header_or_error.clear();
 362
 363                 if (client->state == Client::SENDING_ERROR) {
 364                         // We're done sending the error, so now close.
 365                         // This is postcondition #1.
 366                         close_client(client);
 367                         return;
 368                 }
 369
 370                 // Start sending from the end. In other words, we won't send any of the backlog,
 371                 // but we'll start sending immediately as we get data.
 372                 // This is postcondition #3.
 373                 client->state = Client::SENDING_DATA;
 374                 client->stream_pos = client->stream->bytes_received;
 375                 client->stream->put_client_to_sleep(client);
 376                 return;
 377         }
 378         case Client::SENDING_DATA: {
 379 sending_data_again:
 380                 // See if there's some data we've lost. Ideally, we should drop to a block boundary,
 381                 // but resync will be the mux's problem.
 382                 Stream *stream = client->stream;
 383                 size_t bytes_to_send = stream->bytes_received - client->stream_pos;
 384                 if (bytes_to_send == 0) {
 385                         return;
 386                 }
 387                 if (bytes_to_send > stream->backlog_size) {
 388                         size_t bytes_lost = bytes_to_send - stream->backlog_size;
 389                         client->stream_pos = stream->bytes_received - stream->backlog_size;
 390                         client->bytes_lost += bytes_lost;
 391                         ++client->num_loss_events;
 392                         bytes_to_send = stream->backlog_size;
 393
 394                         double loss_fraction = double(client->bytes_lost) / double(client->bytes_lost + client->bytes_sent);
 395                         log(WARNING, "[%s] Client lost %lld bytes (total loss: %.2f%%), maybe too slow connection",
 396                                 client->remote_addr.c_str(),
 397                                 (long long int)(bytes_lost),
 398                                 100.0 * loss_fraction);
 399                 }
 400
 401                 // See if we need to split across the circular buffer.
 402                 bool more_data = false;
 403                 if ((client->stream_pos % stream->backlog_size) + bytes_to_send > stream->backlog_size) {
 404                         bytes_to_send = stream->backlog_size - (client->stream_pos % stream->backlog_size);
 405                         more_data = true;
 406                 }
 407
 408                 ssize_t ret;
 409                 do {
 410                         loff_t offset = client->stream_pos % stream->backlog_size;
 411                         ret = sendfile(client->sock, stream->data_fd, &offset, bytes_to_send);
 412                 } while (ret == -1 && errno == EINTR);
 413
 414                 if (ret == -1 && errno == EAGAIN) {
 415                         // We're out of socket space, so return; epoll will wake us up
 416                         // when there is more room.
 417                         // This is postcondition #4.
 418                         return;
 419                 }
 420                 if (ret == -1) {
 421                         // Error, close; postcondition #1.
 422                         log_perror("sendfile");
 423                         close_client(client);
 424                         return;
 425                 }
 426                 client->stream_pos += ret;
 427                 client->bytes_sent += ret;
 428
 429                 if (client->stream_pos == stream->bytes_received) {
 430                         // We don't have any more data for this client, so put it to sleep.
 431                         // This is postcondition #3.
 432                         stream->put_client_to_sleep(client);
 433                 } else if (more_data && size_t(ret) == bytes_to_send) {
 434                         goto sending_data_again;
 435                 }
 436                 break;
 437         }
 438         default:
 439                 assert(false);
 440         }
 441 }
 442
 443 int Server::parse_request(Client *client)
 444 {
 445         vector<string> lines = split_lines(client->request);
 446         if (lines.empty()) {
 447                 return 400;  // Bad request (empty).
 448         }
 449
 450         vector<string> request_tokens = split_tokens(lines[0]);
 451         if (request_tokens.size() < 2) {
 452                 return 400;  // Bad request (empty).
 453         }
 454         if (request_tokens[0] != "GET") {
 455                 return 400;  // Should maybe be 405 instead?
 456         }
 457
 458         map<string, int>::const_iterator url_map_it = url_map.find(request_tokens[1]);
 459         if (url_map_it == url_map.end()) {
 460                 return 404;  // Not found.
 461         }
 462
 463         client->url = request_tokens[1];
 464         client->stream = streams[url_map_it->second];
 465         if (client->stream->mark_pool != NULL) {
 466                 client->fwmark = client->stream->mark_pool->get_mark();
 467         } else {
 468                 client->fwmark = 0;  // No mark.
 469         }
 470         if (setsockopt(client->sock, SOL_SOCKET, SO_MARK, &client->fwmark, sizeof(client->fwmark)) == -1) {
 471                 if (client->fwmark != 0) {
 472                         log_perror("setsockopt(SO_MARK)");
 473                 }
 474         }
 475         client->request.clear();
 476
 477         return 200;  // OK!
 478 }
 479
 480 void Server::construct_header(Client *client)
 481 {
 482         Stream *stream = client->stream;
 483         if (stream->encoding == Stream::STREAM_ENCODING_RAW) {
 484                 client->header_or_error = stream->http_header +
 485                         "\r\n" +
 486                         stream->stream_header;
 487         } else if (stream->encoding == Stream::STREAM_ENCODING_METACUBE) {
 488                 client->header_or_error = stream->http_header +
 489                         "Content-encoding: metacube\r\n" +
 490                         "\r\n";
 491                 if (!stream->stream_header.empty()) {
 492                         metacube_block_header hdr;
 493                         memcpy(hdr.sync, METACUBE_SYNC, sizeof(hdr.sync));
 494                         hdr.size = htonl(stream->stream_header.size());
 495                         hdr.flags = htonl(METACUBE_FLAGS_HEADER);
 496                         client->header_or_error.append(
 497                                 string(reinterpret_cast<char *>(&hdr), sizeof(hdr)));
 498                 }
 499                 client->header_or_error.append(stream->stream_header);
 500         } else {
 501                 assert(false);
 502         }
 503
 504         // Switch states.
 505         client->state = Client::SENDING_HEADER;
 506
 507         epoll_event ev;
 508         ev.events = EPOLLOUT | EPOLLET | EPOLLRDHUP;
 509         ev.data.u64 = reinterpret_cast<uint64_t>(client);
 510
 511         if (epoll_ctl(epoll_fd, EPOLL_CTL_MOD, client->sock, &ev) == -1) {
 512                 log_perror("epoll_ctl(EPOLL_CTL_MOD)");
 513                 exit(1);
 514         }
 515 }
 516
 517 void Server::construct_error(Client *client, int error_code)
 518 {
 519         char error[256];
 520         snprintf(error, 256, "HTTP/1.0 %d Error\r\nContent-type: text/plain\r\n\r\nSomething went wrong. Sorry.\r\n",
 521                 error_code);
 522         client->header_or_error = error;
 523
 524         // Switch states.
 525         client->state = Client::SENDING_ERROR;
 526
 527         epoll_event ev;
 528         ev.events = EPOLLOUT | EPOLLET | EPOLLRDHUP;
 529         ev.data.u64 = reinterpret_cast<uint64_t>(client);
 530
 531         if (epoll_ctl(epoll_fd, EPOLL_CTL_MOD, client->sock, &ev) == -1) {
 532                 log_perror("epoll_ctl(EPOLL_CTL_MOD)");
 533                 exit(1);
 534         }
 535 }
 536
 537 template<class T>
 538 void delete_from(vector<T> *v, T elem)
 539 {
 540         typename vector<T>::iterator new_end = remove(v->begin(), v->end(), elem);
 541         v->erase(new_end, v->end());
 542 }
 543
 544 void Server::close_client(Client *client)
 545 {
 546         if (epoll_ctl(epoll_fd, EPOLL_CTL_DEL, client->sock, NULL) == -1) {
 547                 log_perror("epoll_ctl(EPOLL_CTL_DEL)");
 548                 exit(1);
 549         }
 550
 551         // This client could be sleeping, so we'll need to fix that. (Argh, O(n).)
 552         if (client->stream != NULL) {
 553                 delete_from(&client->stream->sleeping_clients, client);
 554                 delete_from(&client->stream->to_process, client);
 555                 if (client->stream->mark_pool != NULL) {
 556                         int fwmark = client->fwmark;
 557                         client->stream->mark_pool->release_mark(fwmark);
 558                 }
 559         }
 560
 561         // Log to access_log.
 562         access_log->write(client->get_stats());
 563
 564         // Bye-bye!
 565         safe_close(client->sock);
 566
 567         clients.erase(client->sock);
 568 }
 569
 570 void Server::process_queued_data()
 571 {
 572         MutexLock lock(&queued_data_mutex);
 573
 574         for (size_t i = 0; i < queued_add_clients.size(); ++i) {
 575                 add_client(queued_add_clients[i]);
 576         }
 577         queued_add_clients.clear();
 578
 579         for (size_t i = 0; i < streams.size(); ++i) {
 580                 streams[i]->process_queued_data();
 581         }
 582 }