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
  30 using namespace std;
  31
  32 extern AccessLogThread *access_log;
  33
  34 Server::Server()
  35 {
  36         pthread_mutex_init(&mutex, NULL);
  37         pthread_mutex_init(&queued_data_mutex, NULL);
  38
  39         epoll_fd = epoll_create(1024);  // Size argument is ignored.
  40         if (epoll_fd == -1) {
  41                 log_perror("epoll_fd");
  42                 exit(1);
  43         }
  44 }
  45
  46 Server::~Server()
  47 {
  48         for (map<string, Stream *>::iterator stream_it = streams.begin();
  49              stream_it != streams.end();
  50              ++stream_it) {
  51                 delete stream_it->second;
  52         }
  53
  54         int ret;
  55         do {
  56                 ret = close(epoll_fd);
  57         } while (ret == -1 && errno == EINTR);
  58
  59         if (ret == -1) {
  60                 log_perror("close(epoll_fd)");
  61         }
  62 }
  63
  64 vector<ClientStats> Server::get_client_stats() const
  65 {
  66         vector<ClientStats> ret;
  67
  68         MutexLock lock(&mutex);
  69         for (map<int, Client>::const_iterator client_it = clients.begin();
  70              client_it != clients.end();
  71              ++client_it) {
  72                 ret.push_back(client_it->second.get_stats());
  73         }
  74         return ret;
  75 }
  76
  77 void Server::do_work()
  78 {
  79         for ( ;; ) {
  80                 int nfds = epoll_wait(epoll_fd, events, EPOLL_MAX_EVENTS, EPOLL_TIMEOUT_MS);
  81                 if (nfds == -1 && errno == EINTR) {
  82                         if (should_stop) {
  83                                 return;
  84                         }
  85                         continue;
  86                 }
  87                 if (nfds == -1) {
  88                         log_perror("epoll_wait");
  89                         exit(1);
  90                 }
  91
  92                 MutexLock lock(&mutex);  // We release the mutex between iterations.
  93
  94                 process_queued_data();
  95
  96                 for (int i = 0; i < nfds; ++i) {
  97                         Client *client = reinterpret_cast<Client *>(events[i].data.u64);
  98
  99                         if (events[i].events & (EPOLLERR | EPOLLRDHUP | EPOLLHUP)) {
 100                                 close_client(client);
 101                                 continue;
 102                         }
 103
 104                         process_client(client);
 105                 }
 106
 107                 for (map<string, Stream *>::iterator stream_it = streams.begin();
 108                      stream_it != streams.end();
 109                      ++stream_it) {
 110                         vector<Client *> to_process;
 111                         swap(stream_it->second->to_process, to_process);
 112                         for (size_t i = 0; i < to_process.size(); ++i) {
 113                                 process_client(to_process[i]);
 114                         }
 115                 }
 116
 117                 if (should_stop) {
 118                         return;
 119                 }
 120         }
 121 }
 122
 123 CubemapStateProto Server::serialize()
 124 {
 125         // We don't serialize anything queued, so empty the queues.
 126         process_queued_data();
 127
 128         CubemapStateProto serialized;
 129         for (map<int, Client>::const_iterator client_it = clients.begin();
 130              client_it != clients.end();
 131              ++client_it) {
 132                 serialized.add_clients()->MergeFrom(client_it->second.serialize());
 133         }
 134         for (map<string, Stream *>::const_iterator stream_it = streams.begin();
 135              stream_it != streams.end();
 136              ++stream_it) {
 137                 serialized.add_streams()->MergeFrom(stream_it->second->serialize());
 138         }
 139         return serialized;
 140 }
 141
 142 void Server::add_client_deferred(int sock)
 143 {
 144         MutexLock lock(&queued_data_mutex);
 145         queued_add_clients.push_back(sock);
 146 }
 147
 148 void Server::add_client(int sock)
 149 {
 150         clients.insert(make_pair(sock, Client(sock)));
 151
 152         // Start listening on data from this socket.
 153         epoll_event ev;
 154         ev.events = EPOLLIN | EPOLLET | EPOLLRDHUP;
 155         ev.data.u64 = reinterpret_cast<uint64_t>(&clients[sock]);
 156         if (epoll_ctl(epoll_fd, EPOLL_CTL_ADD, sock, &ev) == -1) {
 157                 log_perror("epoll_ctl(EPOLL_CTL_ADD)");
 158                 exit(1);
 159         }
 160
 161         process_client(&clients[sock]);
 162 }
 163
 164 void Server::add_client_from_serialized(const ClientProto &client)
 165 {
 166         MutexLock lock(&mutex);
 167         Stream *stream;
 168         map<string, Stream *>::iterator stream_it = streams.find(client.stream_id());
 169         if (stream_it == streams.end()) {
 170                 stream = NULL;
 171         } else {
 172                 stream = stream_it->second;
 173         }
 174         clients.insert(make_pair(client.sock(), Client(client, stream)));
 175         Client *client_ptr = &clients[client.sock()];
 176
 177         // Start listening on data from this socket.
 178         epoll_event ev;
 179         if (client.state() == Client::READING_REQUEST) {
 180                 ev.events = EPOLLIN | EPOLLET | EPOLLRDHUP;
 181         } else {
 182                 // If we don't have more data for this client, we'll be putting it into
 183                 // the sleeping array again soon.
 184                 ev.events = EPOLLOUT | EPOLLET | EPOLLRDHUP;
 185         }
 186         ev.data.u64 = 0;  // Keep Valgrind happy.
 187         ev.data.u64 = reinterpret_cast<uint64_t>(client_ptr);
 188         if (epoll_ctl(epoll_fd, EPOLL_CTL_ADD, client.sock(), &ev) == -1) {
 189                 log_perror("epoll_ctl(EPOLL_CTL_ADD)");
 190                 exit(1);
 191         }
 192
 193         if (client_ptr->state == Client::SENDING_DATA &&
 194             client_ptr->stream_pos == client_ptr->stream->bytes_received) {
 195                 client_ptr->stream->put_client_to_sleep(client_ptr);
 196         } else {
 197                 process_client(client_ptr);
 198         }
 199 }
 200
 201 void Server::add_stream(const string &stream_id, size_t backlog_size, Stream::Encoding encoding)
 202 {
 203         MutexLock lock(&mutex);
 204         streams.insert(make_pair(stream_id, new Stream(stream_id, backlog_size, encoding)));
 205 }
 206
 207 void Server::add_stream_from_serialized(const StreamProto &stream, int data_fd)
 208 {
 209         MutexLock lock(&mutex);
 210         streams.insert(make_pair(stream.stream_id(), new Stream(stream, data_fd)));
 211 }
 212
 213 void Server::set_backlog_size(const string &stream_id, size_t new_size)
 214 {
 215         MutexLock lock(&mutex);
 216         assert(streams.count(stream_id) != 0);
 217         streams[stream_id]->set_backlog_size(new_size);
 218 }
 219
 220 void Server::set_encoding(const string &stream_id, Stream::Encoding encoding)
 221 {
 222         MutexLock lock(&mutex);
 223         assert(streams.count(stream_id) != 0);
 224         streams[stream_id]->encoding = encoding;
 225 }
 226
 227 void Server::set_header(const string &stream_id, const string &http_header, const string &stream_header)
 228 {
 229         MutexLock lock(&mutex);
 230         find_stream(stream_id)->http_header = http_header;
 231         find_stream(stream_id)->stream_header = stream_header;
 232
 233         // If there are clients we haven't sent anything to yet, we should give
 234         // them the header, so push back into the SENDING_HEADER state.
 235         for (map<int, Client>::iterator client_it = clients.begin();
 236              client_it != clients.end();
 237              ++client_it) {
 238                 Client *client = &client_it->second;
 239                 if (client->state == Client::SENDING_DATA &&
 240                     client->stream_pos == 0) {
 241                         construct_header(client);
 242                 }
 243         }
 244 }
 245
 246 void Server::set_mark_pool(const string &stream_id, MarkPool *mark_pool)
 247 {
 248         MutexLock lock(&mutex);
 249         assert(clients.empty());
 250         find_stream(stream_id)->mark_pool = mark_pool;
 251 }
 252
 253 void Server::add_data_deferred(const string &stream_id, const char *data, size_t bytes)
 254 {
 255         MutexLock lock(&queued_data_mutex);
 256         queued_data[stream_id].append(string(data, data + bytes));
 257 }
 258
 259 // See the .h file for postconditions after this function.
 260 void Server::process_client(Client *client)
 261 {
 262         switch (client->state) {
 263         case Client::READING_REQUEST: {
 264 read_request_again:
 265                 // Try to read more of the request.
 266                 char buf[1024];
 267                 int ret;
 268                 do {
 269                         ret = read(client->sock, buf, sizeof(buf));
 270                 } while (ret == -1 && errno == EINTR);
 271
 272                 if (ret == -1 && errno == EAGAIN) {
 273                         // No more data right now. Nothing to do.
 274                         // This is postcondition #2.
 275                         return;
 276                 }
 277                 if (ret == -1) {
 278                         log_perror("read");
 279                         close_client(client);
 280                         return;
 281                 }
 282                 if (ret == 0) {
 283                         // OK, the socket is closed.
 284                         close_client(client);
 285                         return;
 286                 }
 287
 288                 RequestParseStatus status = wait_for_double_newline(&client->request, buf, ret);
 289
 290                 switch (status) {
 291                 case RP_OUT_OF_SPACE:
 292                         log(WARNING, "[%s] Client sent overlong request!", client->remote_addr.c_str());
 293                         close_client(client);
 294                         return;
 295                 case RP_NOT_FINISHED_YET:
 296                         // OK, we don't have the entire header yet. Fine; we'll get it later.
 297                         // See if there's more data for us.
 298                         goto read_request_again;
 299                 case RP_EXTRA_DATA:
 300                         log(WARNING, "[%s] Junk data after request!", client->remote_addr.c_str());
 301                         close_client(client);
 302                         return;
 303                 case RP_FINISHED:
 304                         break;
 305                 }
 306
 307                 assert(status == RP_FINISHED);
 308
 309                 int error_code = parse_request(client);
 310                 if (error_code == 200) {
 311                         construct_header(client);
 312                 } else {
 313                         construct_error(client, error_code);
 314                 }
 315
 316                 // We've changed states, so fall through.
 317                 assert(client->state == Client::SENDING_ERROR ||
 318                        client->state == Client::SENDING_HEADER);
 319         }
 320         case Client::SENDING_ERROR:
 321         case Client::SENDING_HEADER: {
 322 sending_header_or_error_again:
 323                 int ret;
 324                 do {
 325                         ret = write(client->sock,
 326                                     client->header_or_error.data() + client->header_or_error_bytes_sent,
 327                                     client->header_or_error.size() - client->header_or_error_bytes_sent);
 328                 } while (ret == -1 && errno == EINTR);
 329
 330                 if (ret == -1 && errno == EAGAIN) {
 331                         // We're out of socket space, so now we're at the “low edge” of epoll's
 332                         // edge triggering. epoll will tell us when there is more room, so for now,
 333                         // just return.
 334                         // This is postcondition #4.
 335                         return;
 336                 }
 337
 338                 if (ret == -1) {
 339                         // Error! Postcondition #1.
 340                         log_perror("write");
 341                         close_client(client);
 342                         return;
 343                 }
 344
 345                 client->header_or_error_bytes_sent += ret;
 346                 assert(client->header_or_error_bytes_sent <= client->header_or_error.size());
 347
 348                 if (client->header_or_error_bytes_sent < client->header_or_error.size()) {
 349                         // We haven't sent all yet. Fine; go another round.
 350                         goto sending_header_or_error_again;
 351                 }
 352
 353                 // We're done sending the header or error! Clear it to release some memory.
 354                 client->header_or_error.clear();
 355
 356                 if (client->state == Client::SENDING_ERROR) {
 357                         // We're done sending the error, so now close.
 358                         // This is postcondition #1.
 359                         close_client(client);
 360                         return;
 361                 }
 362
 363                 // Start sending from the end. In other words, we won't send any of the backlog,
 364                 // but we'll start sending immediately as we get data.
 365                 // This is postcondition #3.
 366                 client->state = Client::SENDING_DATA;
 367                 client->stream_pos = client->stream->bytes_received;
 368                 client->stream->put_client_to_sleep(client);
 369                 return;
 370         }
 371         case Client::SENDING_DATA: {
 372 sending_data_again:
 373                 // See if there's some data we've lost. Ideally, we should drop to a block boundary,
 374                 // but resync will be the mux's problem.
 375                 Stream *stream = client->stream;
 376                 size_t bytes_to_send = stream->bytes_received - client->stream_pos;
 377                 if (bytes_to_send == 0) {
 378                         return;
 379                 }
 380                 if (bytes_to_send > stream->backlog_size) {
 381                         size_t bytes_lost = bytes_to_send - stream->backlog_size;
 382                         client->stream_pos = stream->bytes_received - stream->backlog_size;
 383                         client->bytes_lost += bytes_lost;
 384                         ++client->num_loss_events;
 385                         bytes_to_send = stream->backlog_size;
 386
 387                         double loss_fraction = double(client->bytes_lost) / double(client->bytes_lost + client->bytes_sent);
 388                         log(WARNING, "[%s] Client lost %lld bytes (total loss: %.2f%%), maybe too slow connection",
 389                                 client->remote_addr.c_str(),
 390                                 (long long int)(bytes_lost),
 391                                 100.0 * loss_fraction);
 392                 }
 393
 394                 // See if we need to split across the circular buffer.
 395                 bool more_data = false;
 396                 if ((client->stream_pos % stream->backlog_size) + bytes_to_send > stream->backlog_size) {
 397                         bytes_to_send = stream->backlog_size - (client->stream_pos % stream->backlog_size);
 398                         more_data = true;
 399                 }
 400
 401                 ssize_t ret;
 402                 do {
 403                         loff_t offset = client->stream_pos % stream->backlog_size;
 404                         ret = sendfile(client->sock, stream->data_fd, &offset, bytes_to_send);
 405                 } while (ret == -1 && errno == EINTR);
 406
 407                 if (ret == -1 && errno == EAGAIN) {
 408                         // We're out of socket space, so return; epoll will wake us up
 409                         // when there is more room.
 410                         // This is postcondition #4.
 411                         return;
 412                 }
 413                 if (ret == -1) {
 414                         // Error, close; postcondition #1.
 415                         log_perror("sendfile");
 416                         close_client(client);
 417                         return;
 418                 }
 419                 client->stream_pos += ret;
 420                 client->bytes_sent += ret;
 421
 422                 if (client->stream_pos == stream->bytes_received) {
 423                         // We don't have any more data for this client, so put it to sleep.
 424                         // This is postcondition #3.
 425                         stream->put_client_to_sleep(client);
 426                 } else if (more_data && size_t(ret) == bytes_to_send) {
 427                         goto sending_data_again;
 428                 }
 429                 break;
 430         }
 431         default:
 432                 assert(false);
 433         }
 434 }
 435
 436 int Server::parse_request(Client *client)
 437 {
 438         vector<string> lines = split_lines(client->request);
 439         if (lines.empty()) {
 440                 return 400;  // Bad request (empty).
 441         }
 442
 443         vector<string> request_tokens = split_tokens(lines[0]);
 444         if (request_tokens.size() < 2) {
 445                 return 400;  // Bad request (empty).
 446         }
 447         if (request_tokens[0] != "GET") {
 448                 return 400;  // Should maybe be 405 instead?
 449         }
 450         if (streams.count(request_tokens[1]) == 0) {
 451                 return 404;  // Not found.
 452         }
 453
 454         client->stream_id = request_tokens[1];
 455         client->stream = find_stream(client->stream_id);
 456         if (client->stream->mark_pool != NULL) {
 457                 client->fwmark = client->stream->mark_pool->get_mark();
 458         } else {
 459                 client->fwmark = 0;  // No mark.
 460         }
 461         if (setsockopt(client->sock, SOL_SOCKET, SO_MARK, &client->fwmark, sizeof(client->fwmark)) == -1) {
 462                 if (client->fwmark != 0) {
 463                         log_perror("setsockopt(SO_MARK)");
 464                 }
 465         }
 466         client->request.clear();
 467
 468         return 200;  // OK!
 469 }
 470
 471 void Server::construct_header(Client *client)
 472 {
 473         Stream *stream = find_stream(client->stream_id);
 474         if (stream->encoding == Stream::STREAM_ENCODING_RAW) {
 475                 client->header_or_error = stream->http_header +
 476                         "\r\n" +
 477                         stream->stream_header;
 478         } else if (stream->encoding == Stream::STREAM_ENCODING_METACUBE) {
 479                 client->header_or_error = stream->http_header +
 480                         "Content-encoding: metacube\r\n" +
 481                         "\r\n";
 482                 if (!stream->stream_header.empty()) {
 483                         metacube_block_header hdr;
 484                         memcpy(hdr.sync, METACUBE_SYNC, sizeof(hdr.sync));
 485                         hdr.size = htonl(stream->stream_header.size());
 486                         hdr.flags = htonl(METACUBE_FLAGS_HEADER);
 487                         client->header_or_error.append(
 488                                 string(reinterpret_cast<char *>(&hdr), sizeof(hdr)));
 489                 }
 490                 client->header_or_error.append(stream->stream_header);
 491         } else {
 492                 assert(false);
 493         }
 494
 495         // Switch states.
 496         client->state = Client::SENDING_HEADER;
 497
 498         epoll_event ev;
 499         ev.events = EPOLLOUT | EPOLLET | EPOLLRDHUP;
 500         ev.data.u64 = reinterpret_cast<uint64_t>(client);
 501
 502         if (epoll_ctl(epoll_fd, EPOLL_CTL_MOD, client->sock, &ev) == -1) {
 503                 log_perror("epoll_ctl(EPOLL_CTL_MOD)");
 504                 exit(1);
 505         }
 506 }
 507
 508 void Server::construct_error(Client *client, int error_code)
 509 {
 510         char error[256];
 511         snprintf(error, 256, "HTTP/1.0 %d Error\r\nContent-type: text/plain\r\n\r\nSomething went wrong. Sorry.\r\n",
 512                 error_code);
 513         client->header_or_error = error;
 514
 515         // Switch states.
 516         client->state = Client::SENDING_ERROR;
 517
 518         epoll_event ev;
 519         ev.events = EPOLLOUT | EPOLLET | EPOLLRDHUP;
 520         ev.data.u64 = reinterpret_cast<uint64_t>(client);
 521
 522         if (epoll_ctl(epoll_fd, EPOLL_CTL_MOD, client->sock, &ev) == -1) {
 523                 log_perror("epoll_ctl(EPOLL_CTL_MOD)");
 524                 exit(1);
 525         }
 526 }
 527
 528 template<class T>
 529 void delete_from(vector<T> *v, T elem)
 530 {
 531         typename vector<T>::iterator new_end = remove(v->begin(), v->end(), elem);
 532         v->erase(new_end, v->end());
 533 }
 534
 535 void Server::close_client(Client *client)
 536 {
 537         if (epoll_ctl(epoll_fd, EPOLL_CTL_DEL, client->sock, NULL) == -1) {
 538                 log_perror("epoll_ctl(EPOLL_CTL_DEL)");
 539                 exit(1);
 540         }
 541
 542         // This client could be sleeping, so we'll need to fix that. (Argh, O(n).)
 543         if (client->stream != NULL) {
 544                 delete_from(&client->stream->sleeping_clients, client);
 545                 delete_from(&client->stream->to_process, client);
 546                 if (client->stream->mark_pool != NULL) {
 547                         int fwmark = client->fwmark;
 548                         client->stream->mark_pool->release_mark(fwmark);
 549                 }
 550         }
 551
 552         // Log to access_log.
 553         access_log->write(client->get_stats());
 554
 555         // Bye-bye!
 556         int ret;
 557         do {
 558                 ret = close(client->sock);
 559         } while (ret == -1 && errno == EINTR);
 560
 561         if (ret == -1) {
 562                 log_perror("close");
 563         }
 564
 565         clients.erase(client->sock);
 566 }
 567
 568 Stream *Server::find_stream(const string &stream_id)
 569 {
 570         map<string, Stream *>::iterator it = streams.find(stream_id);
 571         assert(it != streams.end());
 572         return it->second;
 573 }
 574
 575 void Server::process_queued_data()
 576 {
 577         MutexLock lock(&queued_data_mutex);
 578
 579         for (size_t i = 0; i < queued_add_clients.size(); ++i) {
 580                 add_client(queued_add_clients[i]);
 581         }
 582         queued_add_clients.clear();
 583
 584         for (map<string, string>::iterator queued_it = queued_data.begin();
 585              queued_it != queued_data.end();
 586              ++queued_it) {
 587                 Stream *stream = find_stream(queued_it->first);
 588                 stream->add_data(queued_it->second.data(), queued_it->second.size());
 589                 stream->wake_up_all_clients();
 590         }
 591         queued_data.clear();
 592 }