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 (map<string, Stream *>::iterator stream_it = streams.begin();
  50              stream_it != streams.end();
  51              ++stream_it) {
  52                 delete stream_it->second;
  53         }
  54
  55         safe_close(epoll_fd);
  56 }
  57
  58 vector<ClientStats> Server::get_client_stats() const
  59 {
  60         vector<ClientStats> ret;
  61
  62         MutexLock lock(&mutex);
  63         for (map<int, Client>::const_iterator client_it = clients.begin();
  64              client_it != clients.end();
  65              ++client_it) {
  66                 ret.push_back(client_it->second.get_stats());
  67         }
  68         return ret;
  69 }
  70
  71 void Server::do_work()
  72 {
  73         while (!should_stop()) {
  74                 // Wait until there's activity on at least one of the fds,
  75                 // or 20 ms (about one frame at 50 fps) has elapsed.
  76                 //
  77                 // We could in theory wait forever and rely on wakeup()
  78                 // from add_client_deferred() and add_data_deferred(),
  79                 // but wakeup is a pretty expensive operation, and the
  80                 // two threads might end up fighting over a lock, so it's
  81                 // seemingly (much) more efficient to just have a timeout here.
  82                 int nfds = epoll_pwait(epoll_fd, events, EPOLL_MAX_EVENTS, EPOLL_TIMEOUT_MS, &sigset_without_usr1_block);
  83                 if (nfds == -1 && errno != EINTR) {
  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 }
 114
 115 CubemapStateProto Server::serialize()
 116 {
 117         // We don't serialize anything queued, so empty the queues.
 118         process_queued_data();
 119
 120         CubemapStateProto serialized;
 121         for (map<int, Client>::const_iterator client_it = clients.begin();
 122              client_it != clients.end();
 123              ++client_it) {
 124                 serialized.add_clients()->MergeFrom(client_it->second.serialize());
 125         }
 126         for (map<string, Stream *>::const_iterator stream_it = streams.begin();
 127              stream_it != streams.end();
 128              ++stream_it) {
 129                 serialized.add_streams()->MergeFrom(stream_it->second->serialize());
 130         }
 131         return serialized;
 132 }
 133
 134 void Server::add_client_deferred(int sock)
 135 {
 136         MutexLock lock(&queued_data_mutex);
 137         queued_add_clients.push_back(sock);
 138 }
 139
 140 void Server::add_client(int sock)
 141 {
 142         pair<map<int, Client>::iterator, bool> ret =
 143                 clients.insert(make_pair(sock, Client(sock)));
 144         assert(ret.second == true);  // Should not already exist.
 145         Client *client_ptr = &ret.first->second;
 146
 147         // Start listening on data from this socket.
 148         epoll_event ev;
 149         ev.events = EPOLLIN | EPOLLET | EPOLLRDHUP;
 150         ev.data.u64 = reinterpret_cast<uint64_t>(client_ptr);
 151         if (epoll_ctl(epoll_fd, EPOLL_CTL_ADD, sock, &ev) == -1) {
 152                 log_perror("epoll_ctl(EPOLL_CTL_ADD)");
 153                 exit(1);
 154         }
 155
 156         process_client(client_ptr);
 157 }
 158
 159 void Server::add_client_from_serialized(const ClientProto &client)
 160 {
 161         MutexLock lock(&mutex);
 162         Stream *stream;
 163         map<string, Stream *>::iterator stream_it = streams.find(client.stream_id());
 164         if (stream_it == streams.end()) {
 165                 stream = NULL;
 166         } else {
 167                 stream = stream_it->second;
 168         }
 169         pair<map<int, Client>::iterator, bool> ret =
 170                 clients.insert(make_pair(client.sock(), Client(client, stream)));
 171         assert(ret.second == true);  // Should not already exist.
 172         Client *client_ptr = &ret.first->second;
 173
 174         // Start listening on data from this socket.
 175         epoll_event ev;
 176         if (client.state() == Client::READING_REQUEST) {
 177                 ev.events = EPOLLIN | EPOLLET | EPOLLRDHUP;
 178         } else {
 179                 // If we don't have more data for this client, we'll be putting it into
 180                 // the sleeping array again soon.
 181                 ev.events = EPOLLOUT | EPOLLET | EPOLLRDHUP;
 182         }
 183         ev.data.u64 = 0;  // Keep Valgrind happy.
 184         ev.data.u64 = reinterpret_cast<uint64_t>(client_ptr);
 185         if (epoll_ctl(epoll_fd, EPOLL_CTL_ADD, client.sock(), &ev) == -1) {
 186                 log_perror("epoll_ctl(EPOLL_CTL_ADD)");
 187                 exit(1);
 188         }
 189
 190         if (client_ptr->state == Client::SENDING_DATA &&
 191             client_ptr->stream_pos == client_ptr->stream->bytes_received) {
 192                 client_ptr->stream->put_client_to_sleep(client_ptr);
 193         } else {
 194                 process_client(client_ptr);
 195         }
 196 }
 197
 198 void Server::add_stream(const string &stream_id, size_t backlog_size, Stream::Encoding encoding)
 199 {
 200         MutexLock lock(&mutex);
 201         streams.insert(make_pair(stream_id, new Stream(stream_id, backlog_size, encoding)));
 202 }
 203
 204 void Server::add_stream_from_serialized(const StreamProto &stream, int data_fd)
 205 {
 206         MutexLock lock(&mutex);
 207         streams.insert(make_pair(stream.stream_id(), new Stream(stream, data_fd)));
 208 }
 209
 210 void Server::set_backlog_size(const string &stream_id, size_t new_size)
 211 {
 212         MutexLock lock(&mutex);
 213         assert(streams.count(stream_id) != 0);
 214         streams[stream_id]->set_backlog_size(new_size);
 215 }
 216
 217 void Server::set_encoding(const string &stream_id, Stream::Encoding encoding)
 218 {
 219         MutexLock lock(&mutex);
 220         assert(streams.count(stream_id) != 0);
 221         streams[stream_id]->encoding = encoding;
 222 }
 223
 224 void Server::set_header(const string &stream_id, const string &http_header, const string &stream_header)
 225 {
 226         MutexLock lock(&mutex);
 227         find_stream(stream_id)->http_header = http_header;
 228         find_stream(stream_id)->stream_header = stream_header;
 229
 230         // If there are clients we haven't sent anything to yet, we should give
 231         // them the header, so push back into the SENDING_HEADER state.
 232         for (map<int, Client>::iterator client_it = clients.begin();
 233              client_it != clients.end();
 234              ++client_it) {
 235                 Client *client = &client_it->second;
 236                 if (client->state == Client::SENDING_DATA &&
 237                     client->stream_pos == 0) {
 238                         construct_header(client);
 239                 }
 240         }
 241 }
 242
 243 void Server::set_mark_pool(const string &stream_id, MarkPool *mark_pool)
 244 {
 245         MutexLock lock(&mutex);
 246         assert(clients.empty());
 247         find_stream(stream_id)->mark_pool = mark_pool;
 248 }
 249
 250 void Server::add_data_deferred(const string &stream_id, const char *data, size_t bytes)
 251 {
 252         MutexLock lock(&queued_data_mutex);
 253         find_stream(stream_id)->add_data_deferred(data, bytes);
 254 }
 255
 256 // See the .h file for postconditions after this function.
 257 void Server::process_client(Client *client)
 258 {
 259         switch (client->state) {
 260         case Client::READING_REQUEST: {
 261 read_request_again:
 262                 // Try to read more of the request.
 263                 char buf[1024];
 264                 int ret;
 265                 do {
 266                         ret = read(client->sock, buf, sizeof(buf));
 267                 } while (ret == -1 && errno == EINTR);
 268
 269                 if (ret == -1 && errno == EAGAIN) {
 270                         // No more data right now. Nothing to do.
 271                         // This is postcondition #2.
 272                         return;
 273                 }
 274                 if (ret == -1) {
 275                         log_perror("read");
 276                         close_client(client);
 277                         return;
 278                 }
 279                 if (ret == 0) {
 280                         // OK, the socket is closed.
 281                         close_client(client);
 282                         return;
 283                 }
 284
 285                 RequestParseStatus status = wait_for_double_newline(&client->request, buf, ret);
 286
 287                 switch (status) {
 288                 case RP_OUT_OF_SPACE:
 289                         log(WARNING, "[%s] Client sent overlong request!", client->remote_addr.c_str());
 290                         close_client(client);
 291                         return;
 292                 case RP_NOT_FINISHED_YET:
 293                         // OK, we don't have the entire header yet. Fine; we'll get it later.
 294                         // See if there's more data for us.
 295                         goto read_request_again;
 296                 case RP_EXTRA_DATA:
 297                         log(WARNING, "[%s] Junk data after request!", client->remote_addr.c_str());
 298                         close_client(client);
 299                         return;
 300                 case RP_FINISHED:
 301                         break;
 302                 }
 303
 304                 assert(status == RP_FINISHED);
 305
 306                 int error_code = parse_request(client);
 307                 if (error_code == 200) {
 308                         construct_header(client);
 309                 } else {
 310                         construct_error(client, error_code);
 311                 }
 312
 313                 // We've changed states, so fall through.
 314                 assert(client->state == Client::SENDING_ERROR ||
 315                        client->state == Client::SENDING_HEADER);
 316         }
 317         case Client::SENDING_ERROR:
 318         case Client::SENDING_HEADER: {
 319 sending_header_or_error_again:
 320                 int ret;
 321                 do {
 322                         ret = write(client->sock,
 323                                     client->header_or_error.data() + client->header_or_error_bytes_sent,
 324                                     client->header_or_error.size() - client->header_or_error_bytes_sent);
 325                 } while (ret == -1 && errno == EINTR);
 326
 327                 if (ret == -1 && errno == EAGAIN) {
 328                         // We're out of socket space, so now we're at the “low edge” of epoll's
 329                         // edge triggering. epoll will tell us when there is more room, so for now,
 330                         // just return.
 331                         // This is postcondition #4.
 332                         return;
 333                 }
 334
 335                 if (ret == -1) {
 336                         // Error! Postcondition #1.
 337                         log_perror("write");
 338                         close_client(client);
 339                         return;
 340                 }
 341
 342                 client->header_or_error_bytes_sent += ret;
 343                 assert(client->header_or_error_bytes_sent <= client->header_or_error.size());
 344
 345                 if (client->header_or_error_bytes_sent < client->header_or_error.size()) {
 346                         // We haven't sent all yet. Fine; go another round.
 347                         goto sending_header_or_error_again;
 348                 }
 349
 350                 // We're done sending the header or error! Clear it to release some memory.
 351                 client->header_or_error.clear();
 352
 353                 if (client->state == Client::SENDING_ERROR) {
 354                         // We're done sending the error, so now close.
 355                         // This is postcondition #1.
 356                         close_client(client);
 357                         return;
 358                 }
 359
 360                 // Start sending from the end. In other words, we won't send any of the backlog,
 361                 // but we'll start sending immediately as we get data.
 362                 // This is postcondition #3.
 363                 client->state = Client::SENDING_DATA;
 364                 client->stream_pos = client->stream->bytes_received;
 365                 client->stream->put_client_to_sleep(client);
 366                 return;
 367         }
 368         case Client::SENDING_DATA: {
 369 sending_data_again:
 370                 // See if there's some data we've lost. Ideally, we should drop to a block boundary,
 371                 // but resync will be the mux's problem.
 372                 Stream *stream = client->stream;
 373                 size_t bytes_to_send = stream->bytes_received - client->stream_pos;
 374                 if (bytes_to_send == 0) {
 375                         return;
 376                 }
 377                 if (bytes_to_send > stream->backlog_size) {
 378                         size_t bytes_lost = bytes_to_send - stream->backlog_size;
 379                         client->stream_pos = stream->bytes_received - stream->backlog_size;
 380                         client->bytes_lost += bytes_lost;
 381                         ++client->num_loss_events;
 382                         bytes_to_send = stream->backlog_size;
 383
 384                         double loss_fraction = double(client->bytes_lost) / double(client->bytes_lost + client->bytes_sent);
 385                         log(WARNING, "[%s] Client lost %lld bytes (total loss: %.2f%%), maybe too slow connection",
 386                                 client->remote_addr.c_str(),
 387                                 (long long int)(bytes_lost),
 388                                 100.0 * loss_fraction);
 389                 }
 390
 391                 // See if we need to split across the circular buffer.
 392                 bool more_data = false;
 393                 if ((client->stream_pos % stream->backlog_size) + bytes_to_send > stream->backlog_size) {
 394                         bytes_to_send = stream->backlog_size - (client->stream_pos % stream->backlog_size);
 395                         more_data = true;
 396                 }
 397
 398                 ssize_t ret;
 399                 do {
 400                         loff_t offset = client->stream_pos % stream->backlog_size;
 401                         ret = sendfile(client->sock, stream->data_fd, &offset, bytes_to_send);
 402                 } while (ret == -1 && errno == EINTR);
 403
 404                 if (ret == -1 && errno == EAGAIN) {
 405                         // We're out of socket space, so return; epoll will wake us up
 406                         // when there is more room.
 407                         // This is postcondition #4.
 408                         return;
 409                 }
 410                 if (ret == -1) {
 411                         // Error, close; postcondition #1.
 412                         log_perror("sendfile");
 413                         close_client(client);
 414                         return;
 415                 }
 416                 client->stream_pos += ret;
 417                 client->bytes_sent += ret;
 418
 419                 if (client->stream_pos == stream->bytes_received) {
 420                         // We don't have any more data for this client, so put it to sleep.
 421                         // This is postcondition #3.
 422                         stream->put_client_to_sleep(client);
 423                 } else if (more_data && size_t(ret) == bytes_to_send) {
 424                         goto sending_data_again;
 425                 }
 426                 break;
 427         }
 428         default:
 429                 assert(false);
 430         }
 431 }
 432
 433 int Server::parse_request(Client *client)
 434 {
 435         vector<string> lines = split_lines(client->request);
 436         if (lines.empty()) {
 437                 return 400;  // Bad request (empty).
 438         }
 439
 440         vector<string> request_tokens = split_tokens(lines[0]);
 441         if (request_tokens.size() < 2) {
 442                 return 400;  // Bad request (empty).
 443         }
 444         if (request_tokens[0] != "GET") {
 445                 return 400;  // Should maybe be 405 instead?
 446         }
 447         if (streams.count(request_tokens[1]) == 0) {
 448                 return 404;  // Not found.
 449         }
 450
 451         client->stream_id = request_tokens[1];
 452         client->stream = find_stream(client->stream_id);
 453         if (client->stream->mark_pool != NULL) {
 454                 client->fwmark = client->stream->mark_pool->get_mark();
 455         } else {
 456                 client->fwmark = 0;  // No mark.
 457         }
 458         if (setsockopt(client->sock, SOL_SOCKET, SO_MARK, &client->fwmark, sizeof(client->fwmark)) == -1) {
 459                 if (client->fwmark != 0) {
 460                         log_perror("setsockopt(SO_MARK)");
 461                 }
 462         }
 463         client->request.clear();
 464
 465         return 200;  // OK!
 466 }
 467
 468 void Server::construct_header(Client *client)
 469 {
 470         Stream *stream = find_stream(client->stream_id);
 471         if (stream->encoding == Stream::STREAM_ENCODING_RAW) {
 472                 client->header_or_error = stream->http_header +
 473                         "\r\n" +
 474                         stream->stream_header;
 475         } else if (stream->encoding == Stream::STREAM_ENCODING_METACUBE) {
 476                 client->header_or_error = stream->http_header +
 477                         "Content-encoding: metacube\r\n" +
 478                         "\r\n";
 479                 if (!stream->stream_header.empty()) {
 480                         metacube_block_header hdr;
 481                         memcpy(hdr.sync, METACUBE_SYNC, sizeof(hdr.sync));
 482                         hdr.size = htonl(stream->stream_header.size());
 483                         hdr.flags = htonl(METACUBE_FLAGS_HEADER);
 484                         client->header_or_error.append(
 485                                 string(reinterpret_cast<char *>(&hdr), sizeof(hdr)));
 486                 }
 487                 client->header_or_error.append(stream->stream_header);
 488         } else {
 489                 assert(false);
 490         }
 491
 492         // Switch states.
 493         client->state = Client::SENDING_HEADER;
 494
 495         epoll_event ev;
 496         ev.events = EPOLLOUT | EPOLLET | EPOLLRDHUP;
 497         ev.data.u64 = reinterpret_cast<uint64_t>(client);
 498
 499         if (epoll_ctl(epoll_fd, EPOLL_CTL_MOD, client->sock, &ev) == -1) {
 500                 log_perror("epoll_ctl(EPOLL_CTL_MOD)");
 501                 exit(1);
 502         }
 503 }
 504
 505 void Server::construct_error(Client *client, int error_code)
 506 {
 507         char error[256];
 508         snprintf(error, 256, "HTTP/1.0 %d Error\r\nContent-type: text/plain\r\n\r\nSomething went wrong. Sorry.\r\n",
 509                 error_code);
 510         client->header_or_error = error;
 511
 512         // Switch states.
 513         client->state = Client::SENDING_ERROR;
 514
 515         epoll_event ev;
 516         ev.events = EPOLLOUT | EPOLLET | EPOLLRDHUP;
 517         ev.data.u64 = reinterpret_cast<uint64_t>(client);
 518
 519         if (epoll_ctl(epoll_fd, EPOLL_CTL_MOD, client->sock, &ev) == -1) {
 520                 log_perror("epoll_ctl(EPOLL_CTL_MOD)");
 521                 exit(1);
 522         }
 523 }
 524
 525 template<class T>
 526 void delete_from(vector<T> *v, T elem)
 527 {
 528         typename vector<T>::iterator new_end = remove(v->begin(), v->end(), elem);
 529         v->erase(new_end, v->end());
 530 }
 531
 532 void Server::close_client(Client *client)
 533 {
 534         if (epoll_ctl(epoll_fd, EPOLL_CTL_DEL, client->sock, NULL) == -1) {
 535                 log_perror("epoll_ctl(EPOLL_CTL_DEL)");
 536                 exit(1);
 537         }
 538
 539         // This client could be sleeping, so we'll need to fix that. (Argh, O(n).)
 540         if (client->stream != NULL) {
 541                 delete_from(&client->stream->sleeping_clients, client);
 542                 delete_from(&client->stream->to_process, client);
 543                 if (client->stream->mark_pool != NULL) {
 544                         int fwmark = client->fwmark;
 545                         client->stream->mark_pool->release_mark(fwmark);
 546                 }
 547         }
 548
 549         // Log to access_log.
 550         access_log->write(client->get_stats());
 551
 552         // Bye-bye!
 553         safe_close(client->sock);
 554
 555         clients.erase(client->sock);
 556 }
 557
 558 Stream *Server::find_stream(const string &stream_id)
 559 {
 560         map<string, Stream *>::iterator it = streams.find(stream_id);
 561         assert(it != streams.end());
 562         return it->second;
 563 }
 564
 565 void Server::process_queued_data()
 566 {
 567         MutexLock lock(&queued_data_mutex);
 568
 569         for (size_t i = 0; i < queued_add_clients.size(); ++i) {
 570                 add_client(queued_add_clients[i]);
 571         }
 572         queued_add_clients.clear();
 573
 574         for (map<string, Stream *>::iterator stream_it = streams.begin();
 575              stream_it != streams.end();
 576              ++stream_it) {
 577                 stream_it->second->process_queued_data();
 578         }
 579 }