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 we are waken up due to new queued clients or data.
  76                 int nfds = epoll_pwait(epoll_fd, events, EPOLL_MAX_EVENTS, -1, &sigset_without_usr1_block);
  77                 if (nfds == -1 && errno != EINTR) {
  78                         log_perror("epoll_wait");
  79                         exit(1);
  80                 }
  81
  82                 MutexLock lock(&mutex);  // We release the mutex between iterations.
  83
  84                 process_queued_data();
  85
  86                 for (int i = 0; i < nfds; ++i) {
  87                         Client *client = reinterpret_cast<Client *>(events[i].data.u64);
  88
  89                         if (events[i].events & (EPOLLERR | EPOLLRDHUP | EPOLLHUP)) {
  90                                 close_client(client);
  91                                 continue;
  92                         }
  93
  94                         process_client(client);
  95                 }
  96
  97                 for (map<string, Stream *>::iterator stream_it = streams.begin();
  98                      stream_it != streams.end();
  99                      ++stream_it) {
 100                         vector<Client *> to_process;
 101                         swap(stream_it->second->to_process, to_process);
 102                         for (size_t i = 0; i < to_process.size(); ++i) {
 103                                 process_client(to_process[i]);
 104                         }
 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         wakeup();
 133 }
 134
 135 void Server::add_client(int sock)
 136 {
 137         pair<map<int, Client>::iterator, bool> ret =
 138                 clients.insert(make_pair(sock, Client(sock)));
 139         assert(ret.second == true);  // Should not already exist.
 140         Client *client_ptr = &ret.first->second;
 141
 142         // Start listening on data from this socket.
 143         epoll_event ev;
 144         ev.events = EPOLLIN | EPOLLET | EPOLLRDHUP;
 145         ev.data.u64 = reinterpret_cast<uint64_t>(client_ptr);
 146         if (epoll_ctl(epoll_fd, EPOLL_CTL_ADD, sock, &ev) == -1) {
 147                 log_perror("epoll_ctl(EPOLL_CTL_ADD)");
 148                 exit(1);
 149         }
 150
 151         process_client(client_ptr);
 152 }
 153
 154 void Server::add_client_from_serialized(const ClientProto &client)
 155 {
 156         MutexLock lock(&mutex);
 157         Stream *stream;
 158         map<string, Stream *>::iterator stream_it = streams.find(client.stream_id());
 159         if (stream_it == streams.end()) {
 160                 stream = NULL;
 161         } else {
 162                 stream = stream_it->second;
 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 = 0;  // Keep Valgrind happy.
 179         ev.data.u64 = reinterpret_cast<uint64_t>(client_ptr);
 180         if (epoll_ctl(epoll_fd, EPOLL_CTL_ADD, client.sock(), &ev) == -1) {
 181                 log_perror("epoll_ctl(EPOLL_CTL_ADD)");
 182                 exit(1);
 183         }
 184
 185         if (client_ptr->state == Client::SENDING_DATA &&
 186             client_ptr->stream_pos == client_ptr->stream->bytes_received) {
 187                 client_ptr->stream->put_client_to_sleep(client_ptr);
 188         } else {
 189                 process_client(client_ptr);
 190         }
 191 }
 192
 193 void Server::add_stream(const string &stream_id, size_t backlog_size, Stream::Encoding encoding)
 194 {
 195         MutexLock lock(&mutex);
 196         streams.insert(make_pair(stream_id, new Stream(stream_id, backlog_size, encoding)));
 197 }
 198
 199 void Server::add_stream_from_serialized(const StreamProto &stream, int data_fd)
 200 {
 201         MutexLock lock(&mutex);
 202         streams.insert(make_pair(stream.stream_id(), new Stream(stream, data_fd)));
 203 }
 204
 205 void Server::set_backlog_size(const string &stream_id, size_t new_size)
 206 {
 207         MutexLock lock(&mutex);
 208         assert(streams.count(stream_id) != 0);
 209         streams[stream_id]->set_backlog_size(new_size);
 210 }
 211
 212 void Server::set_encoding(const string &stream_id, Stream::Encoding encoding)
 213 {
 214         MutexLock lock(&mutex);
 215         assert(streams.count(stream_id) != 0);
 216         streams[stream_id]->encoding = encoding;
 217 }
 218
 219 void Server::set_header(const string &stream_id, const string &http_header, const string &stream_header)
 220 {
 221         MutexLock lock(&mutex);
 222         find_stream(stream_id)->http_header = http_header;
 223         find_stream(stream_id)->stream_header = stream_header;
 224
 225         // If there are clients we haven't sent anything to yet, we should give
 226         // them the header, so push back into the SENDING_HEADER state.
 227         for (map<int, Client>::iterator client_it = clients.begin();
 228              client_it != clients.end();
 229              ++client_it) {
 230                 Client *client = &client_it->second;
 231                 if (client->state == Client::SENDING_DATA &&
 232                     client->stream_pos == 0) {
 233                         construct_header(client);
 234                 }
 235         }
 236 }
 237
 238 void Server::set_mark_pool(const string &stream_id, MarkPool *mark_pool)
 239 {
 240         MutexLock lock(&mutex);
 241         assert(clients.empty());
 242         find_stream(stream_id)->mark_pool = mark_pool;
 243 }
 244
 245 void Server::add_data_deferred(const string &stream_id, const char *data, size_t bytes)
 246 {
 247         MutexLock lock(&queued_data_mutex);
 248         queued_data[stream_id].append(string(data, data + bytes));
 249         wakeup();
 250 }
 251
 252 // See the .h file for postconditions after this function.
 253 void Server::process_client(Client *client)
 254 {
 255         switch (client->state) {
 256         case Client::READING_REQUEST: {
 257 read_request_again:
 258                 // Try to read more of the request.
 259                 char buf[1024];
 260                 int ret;
 261                 do {
 262                         ret = read(client->sock, buf, sizeof(buf));
 263                 } while (ret == -1 && errno == EINTR);
 264
 265                 if (ret == -1 && errno == EAGAIN) {
 266                         // No more data right now. Nothing to do.
 267                         // This is postcondition #2.
 268                         return;
 269                 }
 270                 if (ret == -1) {
 271                         log_perror("read");
 272                         close_client(client);
 273                         return;
 274                 }
 275                 if (ret == 0) {
 276                         // OK, the socket is closed.
 277                         close_client(client);
 278                         return;
 279                 }
 280
 281                 RequestParseStatus status = wait_for_double_newline(&client->request, buf, ret);
 282
 283                 switch (status) {
 284                 case RP_OUT_OF_SPACE:
 285                         log(WARNING, "[%s] Client sent overlong request!", client->remote_addr.c_str());
 286                         close_client(client);
 287                         return;
 288                 case RP_NOT_FINISHED_YET:
 289                         // OK, we don't have the entire header yet. Fine; we'll get it later.
 290                         // See if there's more data for us.
 291                         goto read_request_again;
 292                 case RP_EXTRA_DATA:
 293                         log(WARNING, "[%s] Junk data after request!", client->remote_addr.c_str());
 294                         close_client(client);
 295                         return;
 296                 case RP_FINISHED:
 297                         break;
 298                 }
 299
 300                 assert(status == RP_FINISHED);
 301
 302                 int error_code = parse_request(client);
 303                 if (error_code == 200) {
 304                         construct_header(client);
 305                 } else {
 306                         construct_error(client, error_code);
 307                 }
 308
 309                 // We've changed states, so fall through.
 310                 assert(client->state == Client::SENDING_ERROR ||
 311                        client->state == Client::SENDING_HEADER);
 312         }
 313         case Client::SENDING_ERROR:
 314         case Client::SENDING_HEADER: {
 315 sending_header_or_error_again:
 316                 int ret;
 317                 do {
 318                         ret = write(client->sock,
 319                                     client->header_or_error.data() + client->header_or_error_bytes_sent,
 320                                     client->header_or_error.size() - client->header_or_error_bytes_sent);
 321                 } while (ret == -1 && errno == EINTR);
 322
 323                 if (ret == -1 && errno == EAGAIN) {
 324                         // We're out of socket space, so now we're at the “low edge” of epoll's
 325                         // edge triggering. epoll will tell us when there is more room, so for now,
 326                         // just return.
 327                         // This is postcondition #4.
 328                         return;
 329                 }
 330
 331                 if (ret == -1) {
 332                         // Error! Postcondition #1.
 333                         log_perror("write");
 334                         close_client(client);
 335                         return;
 336                 }
 337
 338                 client->header_or_error_bytes_sent += ret;
 339                 assert(client->header_or_error_bytes_sent <= client->header_or_error.size());
 340
 341                 if (client->header_or_error_bytes_sent < client->header_or_error.size()) {
 342                         // We haven't sent all yet. Fine; go another round.
 343                         goto sending_header_or_error_again;
 344                 }
 345
 346                 // We're done sending the header or error! Clear it to release some memory.
 347                 client->header_or_error.clear();
 348
 349                 if (client->state == Client::SENDING_ERROR) {
 350                         // We're done sending the error, so now close.
 351                         // This is postcondition #1.
 352                         close_client(client);
 353                         return;
 354                 }
 355
 356                 // Start sending from the end. In other words, we won't send any of the backlog,
 357                 // but we'll start sending immediately as we get data.
 358                 // This is postcondition #3.
 359                 client->state = Client::SENDING_DATA;
 360                 client->stream_pos = client->stream->bytes_received;
 361                 client->stream->put_client_to_sleep(client);
 362                 return;
 363         }
 364         case Client::SENDING_DATA: {
 365 sending_data_again:
 366                 // See if there's some data we've lost. Ideally, we should drop to a block boundary,
 367                 // but resync will be the mux's problem.
 368                 Stream *stream = client->stream;
 369                 size_t bytes_to_send = stream->bytes_received - client->stream_pos;
 370                 if (bytes_to_send == 0) {
 371                         return;
 372                 }
 373                 if (bytes_to_send > stream->backlog_size) {
 374                         size_t bytes_lost = bytes_to_send - stream->backlog_size;
 375                         client->stream_pos = stream->bytes_received - stream->backlog_size;
 376                         client->bytes_lost += bytes_lost;
 377                         ++client->num_loss_events;
 378                         bytes_to_send = stream->backlog_size;
 379
 380                         double loss_fraction = double(client->bytes_lost) / double(client->bytes_lost + client->bytes_sent);
 381                         log(WARNING, "[%s] Client lost %lld bytes (total loss: %.2f%%), maybe too slow connection",
 382                                 client->remote_addr.c_str(),
 383                                 (long long int)(bytes_lost),
 384                                 100.0 * loss_fraction);
 385                 }
 386
 387                 // See if we need to split across the circular buffer.
 388                 bool more_data = false;
 389                 if ((client->stream_pos % stream->backlog_size) + bytes_to_send > stream->backlog_size) {
 390                         bytes_to_send = stream->backlog_size - (client->stream_pos % stream->backlog_size);
 391                         more_data = true;
 392                 }
 393
 394                 ssize_t ret;
 395                 do {
 396                         loff_t offset = client->stream_pos % stream->backlog_size;
 397                         ret = sendfile(client->sock, stream->data_fd, &offset, bytes_to_send);
 398                 } while (ret == -1 && errno == EINTR);
 399
 400                 if (ret == -1 && errno == EAGAIN) {
 401                         // We're out of socket space, so return; epoll will wake us up
 402                         // when there is more room.
 403                         // This is postcondition #4.
 404                         return;
 405                 }
 406                 if (ret == -1) {
 407                         // Error, close; postcondition #1.
 408                         log_perror("sendfile");
 409                         close_client(client);
 410                         return;
 411                 }
 412                 client->stream_pos += ret;
 413                 client->bytes_sent += ret;
 414
 415                 if (client->stream_pos == stream->bytes_received) {
 416                         // We don't have any more data for this client, so put it to sleep.
 417                         // This is postcondition #3.
 418                         stream->put_client_to_sleep(client);
 419                 } else if (more_data && size_t(ret) == bytes_to_send) {
 420                         goto sending_data_again;
 421                 }
 422                 break;
 423         }
 424         default:
 425                 assert(false);
 426         }
 427 }
 428
 429 int Server::parse_request(Client *client)
 430 {
 431         vector<string> lines = split_lines(client->request);
 432         if (lines.empty()) {
 433                 return 400;  // Bad request (empty).
 434         }
 435
 436         vector<string> request_tokens = split_tokens(lines[0]);
 437         if (request_tokens.size() < 2) {
 438                 return 400;  // Bad request (empty).
 439         }
 440         if (request_tokens[0] != "GET") {
 441                 return 400;  // Should maybe be 405 instead?
 442         }
 443         if (streams.count(request_tokens[1]) == 0) {
 444                 return 404;  // Not found.
 445         }
 446
 447         client->stream_id = request_tokens[1];
 448         client->stream = find_stream(client->stream_id);
 449         if (client->stream->mark_pool != NULL) {
 450                 client->fwmark = client->stream->mark_pool->get_mark();
 451         } else {
 452                 client->fwmark = 0;  // No mark.
 453         }
 454         if (setsockopt(client->sock, SOL_SOCKET, SO_MARK, &client->fwmark, sizeof(client->fwmark)) == -1) {
 455                 if (client->fwmark != 0) {
 456                         log_perror("setsockopt(SO_MARK)");
 457                 }
 458         }
 459         client->request.clear();
 460
 461         return 200;  // OK!
 462 }
 463
 464 void Server::construct_header(Client *client)
 465 {
 466         Stream *stream = find_stream(client->stream_id);
 467         if (stream->encoding == Stream::STREAM_ENCODING_RAW) {
 468                 client->header_or_error = stream->http_header +
 469                         "\r\n" +
 470                         stream->stream_header;
 471         } else if (stream->encoding == Stream::STREAM_ENCODING_METACUBE) {
 472                 client->header_or_error = stream->http_header +
 473                         "Content-encoding: metacube\r\n" +
 474                         "\r\n";
 475                 if (!stream->stream_header.empty()) {
 476                         metacube_block_header hdr;
 477                         memcpy(hdr.sync, METACUBE_SYNC, sizeof(hdr.sync));
 478                         hdr.size = htonl(stream->stream_header.size());
 479                         hdr.flags = htonl(METACUBE_FLAGS_HEADER);
 480                         client->header_or_error.append(
 481                                 string(reinterpret_cast<char *>(&hdr), sizeof(hdr)));
 482                 }
 483                 client->header_or_error.append(stream->stream_header);
 484         } else {
 485                 assert(false);
 486         }
 487
 488         // Switch states.
 489         client->state = Client::SENDING_HEADER;
 490
 491         epoll_event ev;
 492         ev.events = EPOLLOUT | EPOLLET | EPOLLRDHUP;
 493         ev.data.u64 = reinterpret_cast<uint64_t>(client);
 494
 495         if (epoll_ctl(epoll_fd, EPOLL_CTL_MOD, client->sock, &ev) == -1) {
 496                 log_perror("epoll_ctl(EPOLL_CTL_MOD)");
 497                 exit(1);
 498         }
 499 }
 500
 501 void Server::construct_error(Client *client, int error_code)
 502 {
 503         char error[256];
 504         snprintf(error, 256, "HTTP/1.0 %d Error\r\nContent-type: text/plain\r\n\r\nSomething went wrong. Sorry.\r\n",
 505                 error_code);
 506         client->header_or_error = error;
 507
 508         // Switch states.
 509         client->state = Client::SENDING_ERROR;
 510
 511         epoll_event ev;
 512         ev.events = EPOLLOUT | EPOLLET | EPOLLRDHUP;
 513         ev.data.u64 = reinterpret_cast<uint64_t>(client);
 514
 515         if (epoll_ctl(epoll_fd, EPOLL_CTL_MOD, client->sock, &ev) == -1) {
 516                 log_perror("epoll_ctl(EPOLL_CTL_MOD)");
 517                 exit(1);
 518         }
 519 }
 520
 521 template<class T>
 522 void delete_from(vector<T> *v, T elem)
 523 {
 524         typename vector<T>::iterator new_end = remove(v->begin(), v->end(), elem);
 525         v->erase(new_end, v->end());
 526 }
 527
 528 void Server::close_client(Client *client)
 529 {
 530         if (epoll_ctl(epoll_fd, EPOLL_CTL_DEL, client->sock, NULL) == -1) {
 531                 log_perror("epoll_ctl(EPOLL_CTL_DEL)");
 532                 exit(1);
 533         }
 534
 535         // This client could be sleeping, so we'll need to fix that. (Argh, O(n).)
 536         if (client->stream != NULL) {
 537                 delete_from(&client->stream->sleeping_clients, client);
 538                 delete_from(&client->stream->to_process, client);
 539                 if (client->stream->mark_pool != NULL) {
 540                         int fwmark = client->fwmark;
 541                         client->stream->mark_pool->release_mark(fwmark);
 542                 }
 543         }
 544
 545         // Log to access_log.
 546         access_log->write(client->get_stats());
 547
 548         // Bye-bye!
 549         safe_close(client->sock);
 550
 551         clients.erase(client->sock);
 552 }
 553
 554 Stream *Server::find_stream(const string &stream_id)
 555 {
 556         map<string, Stream *>::iterator it = streams.find(stream_id);
 557         assert(it != streams.end());
 558         return it->second;
 559 }
 560
 561 void Server::process_queued_data()
 562 {
 563         MutexLock lock(&queued_data_mutex);
 564
 565         for (size_t i = 0; i < queued_add_clients.size(); ++i) {
 566                 add_client(queued_add_clients[i]);
 567         }
 568         queued_add_clients.clear();
 569
 570         for (map<string, string>::iterator queued_it = queued_data.begin();
 571              queued_it != queued_data.end();
 572              ++queued_it) {
 573                 Stream *stream = find_stream(queued_it->first);
 574                 stream->add_data(queued_it->second.data(), queued_it->second.size());
 575                 stream->wake_up_all_clients();
 576         }
 577         queued_data.clear();
 578 }