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         pair<map<int, Client>::iterator, bool> ret =
 151                 clients.insert(make_pair(sock, Client(sock)));
 152         assert(ret.second == true);  // Should not already exist.
 153         Client *client_ptr = &ret.first->second;
 154
 155         // Start listening on data from this socket.
 156         epoll_event ev;
 157         ev.events = EPOLLIN | EPOLLET | EPOLLRDHUP;
 158         ev.data.u64 = reinterpret_cast<uint64_t>(client_ptr);
 159         if (epoll_ctl(epoll_fd, EPOLL_CTL_ADD, sock, &ev) == -1) {
 160                 log_perror("epoll_ctl(EPOLL_CTL_ADD)");
 161                 exit(1);
 162         }
 163
 164         process_client(client_ptr);
 165 }
 166
 167 void Server::add_client_from_serialized(const ClientProto &client)
 168 {
 169         MutexLock lock(&mutex);
 170         Stream *stream;
 171         map<string, Stream *>::iterator stream_it = streams.find(client.stream_id());
 172         if (stream_it == streams.end()) {
 173                 stream = NULL;
 174         } else {
 175                 stream = stream_it->second;
 176         }
 177         pair<map<int, Client>::iterator, bool> ret =
 178                 clients.insert(make_pair(client.sock(), Client(client, stream)));
 179         assert(ret.second == true);  // Should not already exist.
 180         Client *client_ptr = &ret.first->second;
 181
 182         // Start listening on data from this socket.
 183         epoll_event ev;
 184         if (client.state() == Client::READING_REQUEST) {
 185                 ev.events = EPOLLIN | EPOLLET | EPOLLRDHUP;
 186         } else {
 187                 // If we don't have more data for this client, we'll be putting it into
 188                 // the sleeping array again soon.
 189                 ev.events = EPOLLOUT | EPOLLET | EPOLLRDHUP;
 190         }
 191         ev.data.u64 = 0;  // Keep Valgrind happy.
 192         ev.data.u64 = reinterpret_cast<uint64_t>(client_ptr);
 193         if (epoll_ctl(epoll_fd, EPOLL_CTL_ADD, client.sock(), &ev) == -1) {
 194                 log_perror("epoll_ctl(EPOLL_CTL_ADD)");
 195                 exit(1);
 196         }
 197
 198         if (client_ptr->state == Client::SENDING_DATA &&
 199             client_ptr->stream_pos == client_ptr->stream->bytes_received) {
 200                 client_ptr->stream->put_client_to_sleep(client_ptr);
 201         } else {
 202                 process_client(client_ptr);
 203         }
 204 }
 205
 206 void Server::add_stream(const string &stream_id, size_t backlog_size, Stream::Encoding encoding)
 207 {
 208         MutexLock lock(&mutex);
 209         streams.insert(make_pair(stream_id, new Stream(stream_id, backlog_size, encoding)));
 210 }
 211
 212 void Server::add_stream_from_serialized(const StreamProto &stream, int data_fd)
 213 {
 214         MutexLock lock(&mutex);
 215         streams.insert(make_pair(stream.stream_id(), new Stream(stream, data_fd)));
 216 }
 217
 218 void Server::set_backlog_size(const string &stream_id, size_t new_size)
 219 {
 220         MutexLock lock(&mutex);
 221         assert(streams.count(stream_id) != 0);
 222         streams[stream_id]->set_backlog_size(new_size);
 223 }
 224
 225 void Server::set_encoding(const string &stream_id, Stream::Encoding encoding)
 226 {
 227         MutexLock lock(&mutex);
 228         assert(streams.count(stream_id) != 0);
 229         streams[stream_id]->encoding = encoding;
 230 }
 231
 232 void Server::set_header(const string &stream_id, const string &http_header, const string &stream_header)
 233 {
 234         MutexLock lock(&mutex);
 235         find_stream(stream_id)->http_header = http_header;
 236         find_stream(stream_id)->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(const string &stream_id, MarkPool *mark_pool)
 252 {
 253         MutexLock lock(&mutex);
 254         assert(clients.empty());
 255         find_stream(stream_id)->mark_pool = mark_pool;
 256 }
 257
 258 void Server::add_data_deferred(const string &stream_id, const char *data, size_t bytes)
 259 {
 260         MutexLock lock(&queued_data_mutex);
 261         queued_data[stream_id].append(string(data, data + bytes));
 262 }
 263
 264 // See the .h file for postconditions after this function.
 265 void Server::process_client(Client *client)
 266 {
 267         switch (client->state) {
 268         case Client::READING_REQUEST: {
 269 read_request_again:
 270                 // Try to read more of the request.
 271                 char buf[1024];
 272                 int ret;
 273                 do {
 274                         ret = read(client->sock, buf, sizeof(buf));
 275                 } while (ret == -1 && errno == EINTR);
 276
 277                 if (ret == -1 && errno == EAGAIN) {
 278                         // No more data right now. Nothing to do.
 279                         // This is postcondition #2.
 280                         return;
 281                 }
 282                 if (ret == -1) {
 283                         log_perror("read");
 284                         close_client(client);
 285                         return;
 286                 }
 287                 if (ret == 0) {
 288                         // OK, the socket is closed.
 289                         close_client(client);
 290                         return;
 291                 }
 292
 293                 RequestParseStatus status = wait_for_double_newline(&client->request, buf, ret);
 294
 295                 switch (status) {
 296                 case RP_OUT_OF_SPACE:
 297                         log(WARNING, "[%s] Client sent overlong request!", client->remote_addr.c_str());
 298                         close_client(client);
 299                         return;
 300                 case RP_NOT_FINISHED_YET:
 301                         // OK, we don't have the entire header yet. Fine; we'll get it later.
 302                         // See if there's more data for us.
 303                         goto read_request_again;
 304                 case RP_EXTRA_DATA:
 305                         log(WARNING, "[%s] Junk data after request!", client->remote_addr.c_str());
 306                         close_client(client);
 307                         return;
 308                 case RP_FINISHED:
 309                         break;
 310                 }
 311
 312                 assert(status == RP_FINISHED);
 313
 314                 int error_code = parse_request(client);
 315                 if (error_code == 200) {
 316                         construct_header(client);
 317                 } else {
 318                         construct_error(client, error_code);
 319                 }
 320
 321                 // We've changed states, so fall through.
 322                 assert(client->state == Client::SENDING_ERROR ||
 323                        client->state == Client::SENDING_HEADER);
 324         }
 325         case Client::SENDING_ERROR:
 326         case Client::SENDING_HEADER: {
 327 sending_header_or_error_again:
 328                 int ret;
 329                 do {
 330                         ret = write(client->sock,
 331                                     client->header_or_error.data() + client->header_or_error_bytes_sent,
 332                                     client->header_or_error.size() - client->header_or_error_bytes_sent);
 333                 } while (ret == -1 && errno == EINTR);
 334
 335                 if (ret == -1 && errno == EAGAIN) {
 336                         // We're out of socket space, so now we're at the “low edge” of epoll's
 337                         // edge triggering. epoll will tell us when there is more room, so for now,
 338                         // just return.
 339                         // This is postcondition #4.
 340                         return;
 341                 }
 342
 343                 if (ret == -1) {
 344                         // Error! Postcondition #1.
 345                         log_perror("write");
 346                         close_client(client);
 347                         return;
 348                 }
 349
 350                 client->header_or_error_bytes_sent += ret;
 351                 assert(client->header_or_error_bytes_sent <= client->header_or_error.size());
 352
 353                 if (client->header_or_error_bytes_sent < client->header_or_error.size()) {
 354                         // We haven't sent all yet. Fine; go another round.
 355                         goto sending_header_or_error_again;
 356                 }
 357
 358                 // We're done sending the header or error! Clear it to release some memory.
 359                 client->header_or_error.clear();
 360
 361                 if (client->state == Client::SENDING_ERROR) {
 362                         // We're done sending the error, so now close.
 363                         // This is postcondition #1.
 364                         close_client(client);
 365                         return;
 366                 }
 367
 368                 // Start sending from the end. In other words, we won't send any of the backlog,
 369                 // but we'll start sending immediately as we get data.
 370                 // This is postcondition #3.
 371                 client->state = Client::SENDING_DATA;
 372                 client->stream_pos = client->stream->bytes_received;
 373                 client->stream->put_client_to_sleep(client);
 374                 return;
 375         }
 376         case Client::SENDING_DATA: {
 377 sending_data_again:
 378                 // See if there's some data we've lost. Ideally, we should drop to a block boundary,
 379                 // but resync will be the mux's problem.
 380                 Stream *stream = client->stream;
 381                 size_t bytes_to_send = stream->bytes_received - client->stream_pos;
 382                 if (bytes_to_send == 0) {
 383                         return;
 384                 }
 385                 if (bytes_to_send > stream->backlog_size) {
 386                         size_t bytes_lost = bytes_to_send - stream->backlog_size;
 387                         client->stream_pos = stream->bytes_received - stream->backlog_size;
 388                         client->bytes_lost += bytes_lost;
 389                         ++client->num_loss_events;
 390                         bytes_to_send = stream->backlog_size;
 391
 392                         double loss_fraction = double(client->bytes_lost) / double(client->bytes_lost + client->bytes_sent);
 393                         log(WARNING, "[%s] Client lost %lld bytes (total loss: %.2f%%), maybe too slow connection",
 394                                 client->remote_addr.c_str(),
 395                                 (long long int)(bytes_lost),
 396                                 100.0 * loss_fraction);
 397                 }
 398
 399                 // See if we need to split across the circular buffer.
 400                 bool more_data = false;
 401                 if ((client->stream_pos % stream->backlog_size) + bytes_to_send > stream->backlog_size) {
 402                         bytes_to_send = stream->backlog_size - (client->stream_pos % stream->backlog_size);
 403                         more_data = true;
 404                 }
 405
 406                 ssize_t ret;
 407                 do {
 408                         loff_t offset = client->stream_pos % stream->backlog_size;
 409                         ret = sendfile(client->sock, stream->data_fd, &offset, bytes_to_send);
 410                 } while (ret == -1 && errno == EINTR);
 411
 412                 if (ret == -1 && errno == EAGAIN) {
 413                         // We're out of socket space, so return; epoll will wake us up
 414                         // when there is more room.
 415                         // This is postcondition #4.
 416                         return;
 417                 }
 418                 if (ret == -1) {
 419                         // Error, close; postcondition #1.
 420                         log_perror("sendfile");
 421                         close_client(client);
 422                         return;
 423                 }
 424                 client->stream_pos += ret;
 425                 client->bytes_sent += ret;
 426
 427                 if (client->stream_pos == stream->bytes_received) {
 428                         // We don't have any more data for this client, so put it to sleep.
 429                         // This is postcondition #3.
 430                         stream->put_client_to_sleep(client);
 431                 } else if (more_data && size_t(ret) == bytes_to_send) {
 432                         goto sending_data_again;
 433                 }
 434                 break;
 435         }
 436         default:
 437                 assert(false);
 438         }
 439 }
 440
 441 int Server::parse_request(Client *client)
 442 {
 443         vector<string> lines = split_lines(client->request);
 444         if (lines.empty()) {
 445                 return 400;  // Bad request (empty).
 446         }
 447
 448         vector<string> request_tokens = split_tokens(lines[0]);
 449         if (request_tokens.size() < 2) {
 450                 return 400;  // Bad request (empty).
 451         }
 452         if (request_tokens[0] != "GET") {
 453                 return 400;  // Should maybe be 405 instead?
 454         }
 455         if (streams.count(request_tokens[1]) == 0) {
 456                 return 404;  // Not found.
 457         }
 458
 459         client->stream_id = request_tokens[1];
 460         client->stream = find_stream(client->stream_id);
 461         if (client->stream->mark_pool != NULL) {
 462                 client->fwmark = client->stream->mark_pool->get_mark();
 463         } else {
 464                 client->fwmark = 0;  // No mark.
 465         }
 466         if (setsockopt(client->sock, SOL_SOCKET, SO_MARK, &client->fwmark, sizeof(client->fwmark)) == -1) {
 467                 if (client->fwmark != 0) {
 468                         log_perror("setsockopt(SO_MARK)");
 469                 }
 470         }
 471         client->request.clear();
 472
 473         return 200;  // OK!
 474 }
 475
 476 void Server::construct_header(Client *client)
 477 {
 478         Stream *stream = find_stream(client->stream_id);
 479         if (stream->encoding == Stream::STREAM_ENCODING_RAW) {
 480                 client->header_or_error = stream->http_header +
 481                         "\r\n" +
 482                         stream->stream_header;
 483         } else if (stream->encoding == Stream::STREAM_ENCODING_METACUBE) {
 484                 client->header_or_error = stream->http_header +
 485                         "Content-encoding: metacube\r\n" +
 486                         "\r\n";
 487                 if (!stream->stream_header.empty()) {
 488                         metacube_block_header hdr;
 489                         memcpy(hdr.sync, METACUBE_SYNC, sizeof(hdr.sync));
 490                         hdr.size = htonl(stream->stream_header.size());
 491                         hdr.flags = htonl(METACUBE_FLAGS_HEADER);
 492                         client->header_or_error.append(
 493                                 string(reinterpret_cast<char *>(&hdr), sizeof(hdr)));
 494                 }
 495                 client->header_or_error.append(stream->stream_header);
 496         } else {
 497                 assert(false);
 498         }
 499
 500         // Switch states.
 501         client->state = Client::SENDING_HEADER;
 502
 503         epoll_event ev;
 504         ev.events = EPOLLOUT | EPOLLET | EPOLLRDHUP;
 505         ev.data.u64 = reinterpret_cast<uint64_t>(client);
 506
 507         if (epoll_ctl(epoll_fd, EPOLL_CTL_MOD, client->sock, &ev) == -1) {
 508                 log_perror("epoll_ctl(EPOLL_CTL_MOD)");
 509                 exit(1);
 510         }
 511 }
 512
 513 void Server::construct_error(Client *client, int error_code)
 514 {
 515         char error[256];
 516         snprintf(error, 256, "HTTP/1.0 %d Error\r\nContent-type: text/plain\r\n\r\nSomething went wrong. Sorry.\r\n",
 517                 error_code);
 518         client->header_or_error = error;
 519
 520         // Switch states.
 521         client->state = Client::SENDING_ERROR;
 522
 523         epoll_event ev;
 524         ev.events = EPOLLOUT | EPOLLET | EPOLLRDHUP;
 525         ev.data.u64 = reinterpret_cast<uint64_t>(client);
 526
 527         if (epoll_ctl(epoll_fd, EPOLL_CTL_MOD, client->sock, &ev) == -1) {
 528                 log_perror("epoll_ctl(EPOLL_CTL_MOD)");
 529                 exit(1);
 530         }
 531 }
 532
 533 template<class T>
 534 void delete_from(vector<T> *v, T elem)
 535 {
 536         typename vector<T>::iterator new_end = remove(v->begin(), v->end(), elem);
 537         v->erase(new_end, v->end());
 538 }
 539
 540 void Server::close_client(Client *client)
 541 {
 542         if (epoll_ctl(epoll_fd, EPOLL_CTL_DEL, client->sock, NULL) == -1) {
 543                 log_perror("epoll_ctl(EPOLL_CTL_DEL)");
 544                 exit(1);
 545         }
 546
 547         // This client could be sleeping, so we'll need to fix that. (Argh, O(n).)
 548         if (client->stream != NULL) {
 549                 delete_from(&client->stream->sleeping_clients, client);
 550                 delete_from(&client->stream->to_process, client);
 551                 if (client->stream->mark_pool != NULL) {
 552                         int fwmark = client->fwmark;
 553                         client->stream->mark_pool->release_mark(fwmark);
 554                 }
 555         }
 556
 557         // Log to access_log.
 558         access_log->write(client->get_stats());
 559
 560         // Bye-bye!
 561         int ret;
 562         do {
 563                 ret = close(client->sock);
 564         } while (ret == -1 && errno == EINTR);
 565
 566         if (ret == -1) {
 567                 log_perror("close");
 568         }
 569
 570         clients.erase(client->sock);
 571 }
 572
 573 Stream *Server::find_stream(const string &stream_id)
 574 {
 575         map<string, Stream *>::iterator it = streams.find(stream_id);
 576         assert(it != streams.end());
 577         return it->second;
 578 }
 579
 580 void Server::process_queued_data()
 581 {
 582         MutexLock lock(&queued_data_mutex);
 583
 584         for (size_t i = 0; i < queued_add_clients.size(); ++i) {
 585                 add_client(queued_add_clients[i]);
 586         }
 587         queued_add_clients.clear();
 588
 589         for (map<string, string>::iterator queued_it = queued_data.begin();
 590              queued_it != queued_data.end();
 591              ++queued_it) {
 592                 Stream *stream = find_stream(queued_it->first);
 593                 stream->add_data(queued_it->second.data(), queued_it->second.size());
 594                 stream->wake_up_all_clients();
 595         }
 596         queued_data.clear();
 597 }