client_common.c

   1 /*
   2  * Copyright (C) 1997 Andre Noll <maan@tuebingen.mpg.de>
   3  *
   4  * Licensed under the GPL v2. For licencing details see COPYING.
   5  */
   6
   7 /** \file client_common.c Common functions of para_client and para_audiod. */
   8
   9 #include <netinet/in.h>
  10 #include <sys/socket.h>
  11 #include <regex.h>
  12 #include <sys/types.h>
  13 #include <arpa/inet.h>
  14 #include <sys/un.h>
  15 #include <netdb.h>
  16
  17 #include "para.h"
  18 #include "error.h"
  19 #include "list.h"
  20 #include "sched.h"
  21 #include "crypt.h"
  22 #include "net.h"
  23 #include "fd.h"
  24 #include "sideband.h"
  25 #include "string.h"
  26 #include "client.cmdline.h"
  27 #include "client.h"
  28 #include "buffer_tree.h"
  29 #include "version.h"
  30 #include "ggo.h"
  31
  32 /** The size of the receiving buffer. */
  33 #define CLIENT_BUFSIZE 4000
  34
  35 /**
  36  * Close the connection to para_server and free all resources.
  37  *
  38  * \param ct Pointer to the client data.
  39  *
  40  * \sa \ref client_open().
  41  */
  42 void client_close(struct client_task *ct)
  43 {
  44         if (!ct)
  45                 return;
  46         free(ct->user);
  47         free(ct->config_file);
  48         free(ct->key_file);
  49         client_cmdline_parser_free(&ct->conf);
  50         free(ct->challenge_hash);
  51         sb_free(ct->sbc[0]);
  52         sb_free(ct->sbc[1]);
  53         free(ct);
  54 }
  55
  56 /*
  57  * The preselect hook for server commands.
  58  *
  59  * The task pointer must contain a pointer to the initialized client data
  60  * structure as it is returned by client_open().
  61  *
  62  * This function checks the state of the connection and adds the file descriptor
  63  * of the connection to the read or write fd set of s accordingly.
  64  */
  65 static void client_pre_select(struct sched *s, void *context)
  66 {
  67         int ret;
  68         struct client_task *ct = context;
  69
  70         if (ct->scc.fd < 0)
  71                 return;
  72         switch (ct->status) {
  73         case CL_CONNECTED:
  74         case CL_SENT_AUTH:
  75         case CL_SENT_CH_RESPONSE:
  76                 para_fd_set(ct->scc.fd, &s->rfds, &s->max_fileno);
  77                 return;
  78
  79         case CL_RECEIVED_WELCOME:
  80         case CL_RECEIVED_PROCEED:
  81         case CL_RECEIVED_CHALLENGE:
  82                 para_fd_set(ct->scc.fd, &s->wfds, &s->max_fileno);
  83                 return;
  84
  85         case CL_SENDING:
  86                 if (ct->btrn[1]) {
  87                         ret = btr_node_status(ct->btrn[1], 0, BTR_NT_LEAF);
  88                         if (ret < 0)
  89                                 sched_min_delay(s);
  90                         else if (ret > 0)
  91                                 para_fd_set(ct->scc.fd, &s->wfds, &s->max_fileno);
  92                 }
  93                 /* fall though */
  94         case CL_EXECUTING:
  95                 if (ct->btrn[0]) {
  96                         ret = btr_node_status(ct->btrn[0], 0, BTR_NT_ROOT);
  97                         if (ret < 0)
  98                                 sched_min_delay(s);
  99                         else if (ret > 0)
 100                                 para_fd_set(ct->scc.fd, &s->rfds, &s->max_fileno);
 101                 }
 102                 return;
 103         }
 104 }
 105
 106 static int send_sb(struct client_task *ct, int channel, void *buf, size_t numbytes,
 107                 enum sb_designator band, bool dont_free)
 108 {
 109         int ret, fd = ct->scc.fd;
 110         struct iovec iov[2];
 111
 112         if (!ct->sbc[channel]) {
 113                 struct sb_buffer sbb;
 114                 sb_transformation trafo = ct->status < CL_RECEIVED_PROCEED?
 115                         NULL : sc_trafo;
 116                 sbb = (typeof(sbb))SBB_INIT(band, buf, numbytes);
 117                 ct->sbc[channel] = sb_new_send(&sbb, dont_free, trafo, ct->scc.send);
 118         }
 119         ret = sb_get_send_buffers(ct->sbc[channel], iov);
 120         ret = xwritev(fd, iov, ret);
 121         if (ret < 0) {
 122                 sb_free(ct->sbc[channel]);
 123                 ct->sbc[channel] = NULL;
 124                 return ret;
 125         }
 126         if (sb_sent(ct->sbc[channel], ret)) {
 127                 ct->sbc[channel] = NULL;
 128                 return 1;
 129         }
 130         return 0;
 131 }
 132
 133 static int recv_sb(struct client_task *ct, fd_set *rfds,
 134                 struct sb_buffer *result)
 135 {
 136         int ret;
 137         size_t n;
 138         sb_transformation trafo;
 139         void *trafo_context;
 140         struct iovec iov;
 141
 142         if (!FD_ISSET(ct->scc.fd, rfds))
 143                 return 0;
 144         if (ct->status < CL_SENT_CH_RESPONSE)
 145                 trafo = trafo_context = NULL;
 146         else {
 147                 trafo = sc_trafo;
 148                 trafo_context = ct->scc.recv;
 149         }
 150         if (!ct->sbc[0])
 151                 ct->sbc[0] = sb_new_recv(0, trafo, trafo_context);
 152 again:
 153         sb_get_recv_buffer(ct->sbc[0], &iov);
 154         ret = read_nonblock(ct->scc.fd, iov.iov_base, iov.iov_len, rfds, &n);
 155         if (ret < 0) {
 156                 sb_free(ct->sbc[0]);
 157                 ct->sbc[0] = NULL;
 158                 return ret;
 159         }
 160         if (n == 0)
 161                 return 0;
 162         ret = sb_received(ct->sbc[0], n, result);
 163         if (ret < 0)
 164                 return ret;
 165         if (ret == 0)
 166                 goto again;
 167         ct->sbc[0] = NULL;
 168         return 1;
 169 }
 170
 171
 172 static char **parse_features(char *buf)
 173 {
 174         int i;
 175         const char id[] = "\nFeatures: ";
 176         char *p, *q, **features;
 177
 178         p = strstr(buf, id);
 179         if (!p)
 180                 return NULL;
 181         p += strlen(id);
 182         q = strchr(p, '\n');
 183         if (!q)
 184                 return NULL;
 185         *q = '\0';
 186         create_argv(p, ",", &features);
 187         for (i = 0; features[i]; i++)
 188                 PARA_INFO_LOG("server feature: %s\n", features[i]);
 189         return features;
 190 }
 191
 192 static int dispatch_sbb(struct client_task *ct, struct sb_buffer *sbb)
 193 {
 194         int ret;
 195         const char *designator[] = {SB_DESIGNATORS_ARRAY};
 196
 197         if (!sbb)
 198                 return 0;
 199         if (sbb->band < NUM_SB_DESIGNATORS)
 200                 PARA_DEBUG_LOG("band: %s\n", designator[sbb->band]);
 201
 202         switch (sbb->band) {
 203         case SBD_AWAITING_DATA:
 204                 ct->status = CL_SENDING;
 205                 ret = 1;
 206                 goto out;
 207         case SBD_OUTPUT:
 208                 if (iov_valid(&sbb->iov))
 209                         btr_add_output(sbb->iov.iov_base, sbb->iov.iov_len,
 210                                 ct->btrn[0]);
 211                 ret = 1;
 212                 goto out;
 213         case SBD_DEBUG_LOG:
 214         case SBD_INFO_LOG:
 215         case SBD_NOTICE_LOG:
 216         case SBD_WARNING_LOG:
 217         case SBD_ERROR_LOG:
 218         case SBD_CRIT_LOG:
 219         case SBD_EMERG_LOG:
 220                 if (iov_valid(&sbb->iov)) {
 221                         int ll = sbb->band - SBD_DEBUG_LOG;
 222                         para_log(ll, "remote: %s", (char *)sbb->iov.iov_base);
 223                 }
 224                 ret = 1;
 225                 goto deallocate;
 226         case SBD_EXIT__SUCCESS:
 227                 ret = -E_SERVER_CMD_SUCCESS;
 228                 goto deallocate;
 229         case SBD_EXIT__FAILURE:
 230                 ret = -E_SERVER_CMD_FAILURE;
 231                 goto deallocate;
 232         default:
 233                 PARA_ERROR_LOG("invalid band %d\n", sbb->band);
 234                 ret = -E_BAD_BAND;
 235                 goto deallocate;
 236         }
 237 deallocate:
 238         free(sbb->iov.iov_base);
 239 out:
 240         sbb->iov.iov_base = NULL;
 241         return ret;
 242 }
 243
 244 static bool has_feature(const char *feature, struct client_task *ct)
 245 {
 246         return find_arg(feature, ct->features) >= 0? true : false;
 247 }
 248
 249 static int send_sb_command(struct client_task *ct)
 250 {
 251         int i;
 252         char *command, *p;
 253         size_t len = 0;
 254
 255         if (ct->sbc[1])
 256                 return send_sb(ct, 0, NULL, 0, 0, false);
 257
 258         for (i = 0; i < ct->conf.inputs_num; i++)
 259                 len += strlen(ct->conf.inputs[i]) + 1;
 260         p = command = para_malloc(len);
 261         for (i = 0; i < ct->conf.inputs_num; i++) {
 262                 strcpy(p, ct->conf.inputs[i]);
 263                 p += strlen(ct->conf.inputs[i]) + 1;
 264         }
 265         PARA_DEBUG_LOG("--> %s\n", command);
 266         return send_sb(ct, 0, command, len, SBD_COMMAND, false);
 267 }
 268
 269 /*
 270  * The post select hook for client commands.
 271  *
 272  * Depending on the current state of the connection and the status of the read
 273  * and write fd sets of s, this function performs the necessary steps to
 274  * authenticate the connection, to send the command given by t->private_data
 275  * and to receive para_server's output, if any.
 276  */
 277 static int client_post_select(struct sched *s, void *context)
 278 {
 279         struct client_task *ct = context;
 280         int ret = 0;
 281         size_t n;
 282         char buf[CLIENT_BUFSIZE];
 283
 284         ret = task_get_notification(ct->task);
 285         if (ret < 0)
 286                 goto out;
 287         if (ct->scc.fd < 0)
 288                 return 0;
 289         switch (ct->status) {
 290         case CL_CONNECTED: /* receive welcome message */
 291                 ret = read_nonblock(ct->scc.fd, buf, sizeof(buf), &s->rfds, &n);
 292                 if (ret < 0 || n == 0)
 293                         goto out;
 294                 ct->features = parse_features(buf);
 295                 ct->status = CL_RECEIVED_WELCOME;
 296                 return 0;
 297         case CL_RECEIVED_WELCOME: /* send auth command */
 298                 if (!FD_ISSET(ct->scc.fd, &s->wfds))
 299                         return 0;
 300                 sprintf(buf, AUTH_REQUEST_MSG "%s sideband%s", ct->user,
 301                         has_feature("aes_ctr128", ct)? ",aes_ctr128" : "");
 302                 PARA_INFO_LOG("--> %s\n", buf);
 303                 ret = write_buffer(ct->scc.fd, buf);
 304                 if (ret < 0)
 305                         goto out;
 306                 ct->status = CL_SENT_AUTH;
 307                 return 0;
 308         case CL_SENT_AUTH:
 309                 /*
 310                  * Receive challenge and session keys, decrypt the challenge and
 311                  * send back the hash of the decrypted challenge.
 312                  */
 313                 {
 314                 /* decrypted challenge/session key buffer */
 315                 unsigned char crypt_buf[1024];
 316                 struct sb_buffer sbb;
 317                 bool use_aes;
 318
 319                 ret = recv_sb(ct, &s->rfds, &sbb);
 320                 if (ret <= 0)
 321                         goto out;
 322                 if (sbb.band != SBD_CHALLENGE) {
 323                         ret = -E_BAD_BAND;
 324                         free(sbb.iov.iov_base);
 325                                 goto out;
 326                 }
 327                 n = sbb.iov.iov_len;
 328                 PARA_INFO_LOG("<-- [challenge] (%zu bytes)\n", n);
 329                 ret = priv_decrypt(ct->key_file, crypt_buf,
 330                         sbb.iov.iov_base, n);
 331                 free(sbb.iov.iov_base);
 332                 if (ret < 0)
 333                         goto out;
 334                 ct->challenge_hash = para_malloc(HASH_SIZE);
 335                 hash_function((char *)crypt_buf, CHALLENGE_SIZE, ct->challenge_hash);
 336                 use_aes = has_feature("aes_ctr128", ct);
 337                 ct->scc.send = sc_new(crypt_buf + CHALLENGE_SIZE, SESSION_KEY_LEN, use_aes);
 338                 ct->scc.recv = sc_new(crypt_buf + CHALLENGE_SIZE + SESSION_KEY_LEN,
 339                         SESSION_KEY_LEN, use_aes);
 340                 hash_to_asc(ct->challenge_hash, buf);
 341                 PARA_INFO_LOG("--> %s\n", buf);
 342                 ct->status = CL_RECEIVED_CHALLENGE;
 343                 return 0;
 344                 }
 345         case CL_RECEIVED_CHALLENGE:
 346                 ret = send_sb(ct, 0, ct->challenge_hash, HASH_SIZE,
 347                         SBD_CHALLENGE_RESPONSE, false);
 348                 if (ret != 0)
 349                         ct->challenge_hash = NULL;
 350                 if (ret <= 0)
 351                         goto out;
 352                 ct->status = CL_SENT_CH_RESPONSE;
 353                 goto out;
 354         case CL_SENT_CH_RESPONSE: /* read server response */
 355                 {
 356                 struct sb_buffer sbb;
 357                 ret = recv_sb(ct, &s->rfds, &sbb);
 358                 if (ret <= 0)
 359                         goto out;
 360                 free(sbb.iov.iov_base);
 361                 if (sbb.band != SBD_PROCEED)
 362                         ret = -E_BAD_BAND;
 363                 else
 364                         ct->status = CL_RECEIVED_PROCEED;
 365                 goto out;
 366                 }
 367         case CL_RECEIVED_PROCEED: /* concat args and send command */
 368                 {
 369                 if (!FD_ISSET(ct->scc.fd, &s->wfds))
 370                         return 0;
 371                 ret = send_sb_command(ct);
 372                 if (ret <= 0)
 373                         goto out;
 374                 ct->status = CL_EXECUTING;
 375                 return 0;
 376                 }
 377         case CL_SENDING:
 378                 if (ct->btrn[1]) {
 379                         char *buf2;
 380                         size_t sz;
 381                         ret = btr_node_status(ct->btrn[1], 0, BTR_NT_LEAF);
 382                         if (ret == -E_BTR_EOF) {
 383                                 /* empty blob data packet indicates EOF */
 384                                 PARA_INFO_LOG("blob sent\n");
 385                                 ret = send_sb(ct, 1, NULL, 0, SBD_BLOB_DATA, true);
 386                                 if (ret >= 0)
 387                                         ret = -E_BTR_EOF;
 388                         }
 389                         if (ret < 0)
 390                                 goto close1;
 391                         if (ret > 0 && FD_ISSET(ct->scc.fd, &s->wfds)) {
 392                                 sz = btr_next_buffer(ct->btrn[1], &buf2);
 393                                 assert(sz);
 394                                 ret = send_sb(ct, 1, buf2, sz, SBD_BLOB_DATA, true);
 395                                 if (ret < 0)
 396                                         goto close1;
 397                                 if (ret > 0)
 398                                         btr_consume(ct->btrn[1], sz);
 399                         }
 400                 }
 401                 /* fall through */
 402         case CL_EXECUTING:
 403                 if (ct->btrn[0]) {
 404                         ret = btr_node_status(ct->btrn[0], 0, BTR_NT_ROOT);
 405                         if (ret < 0)
 406                                 goto close0;
 407                         if (ret > 0 && FD_ISSET(ct->scc.fd, &s->rfds)) {
 408                                 struct sb_buffer sbb;
 409                                 ret = recv_sb(ct, &s->rfds, &sbb);
 410                                 if (ret < 0)
 411                                         goto close0;
 412                                 if (ret > 0) {
 413                                         ret = dispatch_sbb(ct, &sbb);
 414                                         if (ret < 0)
 415                                                 goto close0;
 416                                 }
 417                         }
 418                 }
 419                 ret = 0;
 420                 goto out;
 421         }
 422 close1:
 423         PARA_INFO_LOG("channel 1: %s\n", para_strerror(-ret));
 424         btr_remove_node(&ct->btrn[1]);
 425         if (ct->btrn[0])
 426                 return 0;
 427         goto out;
 428 close0:
 429         PARA_INFO_LOG("channel 0: %s\n", para_strerror(-ret));
 430         btr_remove_node(&ct->btrn[0]);
 431         if (ct->btrn[1] && ct->status == CL_SENDING)
 432                 return 0;
 433 out:
 434         if (ret >= 0)
 435                 return 0;
 436         btr_remove_node(&ct->btrn[0]);
 437         btr_remove_node(&ct->btrn[1]);
 438         if (ret != -E_SERVER_CMD_SUCCESS && ret != -E_SERVER_CMD_FAILURE)
 439                 PARA_ERROR_LOG("%s\n", para_strerror(-ret));
 440         if (ct->scc.fd >= 0) {
 441                 close(ct->scc.fd);
 442                 ct->scc.fd = -1;
 443         }
 444         free_argv(ct->features);
 445         ct->features = NULL;
 446         sc_free(ct->scc.recv);
 447         ct->scc.recv = NULL;
 448         sc_free(ct->scc.send);
 449         ct->scc.send = NULL;
 450         return ret;
 451 }
 452
 453 /**
 454  * Connect to para_server and register the client task.
 455  *
 456  * \param ct The initialized client task structure.
 457  * \param s The scheduler instance to register the client task to.
 458  * \param parent The parent node of the client btr node.
 459  * \param child The child node of the client node.
 460  *
 461  * The client task structure given by \a ct  must be allocated and initialized
 462  * by \ref client_parse_config() before this function is called.
 463  *
 464  * \return Standard.
 465  */
 466 int client_connect(struct client_task *ct, struct sched *s,
 467                 struct btr_node *parent, struct btr_node *child)
 468 {
 469         int ret;
 470
 471         PARA_NOTICE_LOG("connecting %s:%d\n", ct->conf.hostname_arg,
 472                 ct->conf.server_port_arg);
 473         ct->scc.fd = -1;
 474         ret = para_connect_simple(IPPROTO_TCP, ct->conf.hostname_arg,
 475                                                ct->conf.server_port_arg);
 476         if (ret < 0)
 477                 return ret;
 478         ct->scc.fd = ret;
 479         ret = mark_fd_nonblocking(ct->scc.fd);
 480         if (ret < 0)
 481                 goto err_out;
 482         ct->status = CL_CONNECTED;
 483         ct->btrn[0] = btr_new_node(&(struct btr_node_description)
 484                 EMBRACE(.name = "client recv", .parent = NULL, .child = child));
 485         ct->btrn[1] = btr_new_node(&(struct btr_node_description)
 486                 EMBRACE(.name = "client send", .parent = parent, .child = NULL));
 487
 488         ct->task = task_register(&(struct task_info) {
 489                 .name = "client",
 490                 .pre_select = client_pre_select,
 491                 .post_select = client_post_select,
 492                 .context = ct,
 493         }, s);
 494         return 1;
 495 err_out:
 496         close(ct->scc.fd);
 497         ct->scc.fd = -1;
 498         return ret;
 499 }
 500
 501 __noreturn static void print_help_and_die(struct client_task *ct)
 502 {
 503         struct ggo_help h = DEFINE_GGO_HELP(client);
 504         bool d = ct->conf.detailed_help_given;
 505
 506         ggo_print_help(&h, d? GPH_STANDARD_FLAGS_DETAILED : GPH_STANDARD_FLAGS);
 507         exit(0);
 508 }
 509
 510 /**
 511  * Parse a client configuration.
 512  *
 513  * \param argc Usual argument count.
 514  * \param argv Usual argument vector.
 515  * \param ct_ptr Filled in by this function.
 516  * \param loglevel If not \p NULL, the number of the loglevel is stored here.
 517  *
 518  * This checks the command line options given by \a argc and \a argv, sets
 519  * default values for the user name and the name of the rsa key file and reads
 520  * further options from the config file.
 521  *
 522  * Upon successful return, \a ct_ptr points to a dynamically allocated and
 523  * initialized client task struct.
 524  *
 525  * \return The number of non-option arguments in \a argc/argv on success,
 526  * negative on errors.
 527  */
 528 int client_parse_config(int argc, char *argv[], struct client_task **ct_ptr,
 529                 int *loglevel)
 530 {
 531         char *home = para_homedir();
 532         int ret;
 533         struct client_task *ct = para_calloc(sizeof(struct client_task));
 534
 535         *ct_ptr = ct;
 536         ct->scc.fd = -1;
 537         ret = -E_CLIENT_SYNTAX;
 538         if (client_cmdline_parser(argc, argv, &ct->conf))
 539                 goto out;
 540         version_handle_flag("client", ct->conf.version_given);
 541         if (ct->conf.help_given || ct->conf.detailed_help_given)
 542                 print_help_and_die(ct);
 543
 544         ct->config_file = ct->conf.config_file_given?
 545                 para_strdup(ct->conf.config_file_arg) :
 546                 make_message("%s/.paraslash/client.conf", home);
 547         ret = file_exists(ct->config_file);
 548         if (!ret && ct->conf.config_file_given) {
 549                 ret = -E_NO_CONFIG;
 550                 goto out;
 551         }
 552         if (ret) {
 553                 struct client_cmdline_parser_params params = {
 554                         .override = 0,
 555                         .initialize = 0,
 556                         .check_required = 0,
 557                         .check_ambiguity = 0,
 558                         .print_errors = 0
 559                 };
 560                 ret = -E_BAD_CONFIG;
 561                 if (client_cmdline_parser_config_file(ct->config_file,
 562                         &ct->conf, &params))
 563                         goto out;
 564         }
 565         ct->user = ct->conf.user_given?
 566                 para_strdup(ct->conf.user_arg) : para_logname();
 567
 568         if (ct->conf.key_file_given)
 569                 ct->key_file = para_strdup(ct->conf.key_file_arg);
 570         else {
 571                 ct->key_file = make_message("%s/.paraslash/key.%s",
 572                         home, ct->user);
 573                 if (!file_exists(ct->key_file)) {
 574                         free(ct->key_file);
 575                         ct->key_file = make_message("%s/.ssh/id_rsa", home);
 576                 }
 577         }
 578
 579         if (loglevel)
 580                 *loglevel = get_loglevel_by_name(ct->conf.loglevel_arg);
 581         PARA_INFO_LOG("loglevel: %s\n", ct->conf.loglevel_arg);
 582         PARA_INFO_LOG("config_file: %s\n", ct->config_file);
 583         PARA_INFO_LOG("key_file: %s\n", ct->key_file);
 584         ret = ct->conf.inputs_num;
 585 out:
 586         free(home);
 587         if (ret < 0) {
 588                 PARA_ERROR_LOG("%s\n", para_strerror(-ret));
 589                 client_close(ct);
 590                 *ct_ptr = NULL;
 591         }
 592         return ret;
 593 }
 594
 595 /**
 596  * Parse the client configuration and open a connection to para_server.
 597  *
 598  * \param argc See \ref client_parse_config.
 599  * \param argv See \ref client_parse_config.
 600  * \param ct_ptr See \ref client_parse_config.
 601  * \param loglevel See \ref client_parse_config.
 602  * \param parent See \ref client_connect().
 603  * \param child See \ref client_connect().
 604  * \param sched See \ref client_connect().
 605  *
 606  * This function combines client_parse_config() and client_connect(). It is
 607  * considered a syntax error if no command was given, i.e. if the number
 608  * of non-option arguments is zero.
 609  *
 610  * \return Standard.
 611  */
 612 int client_open(int argc, char *argv[], struct client_task **ct_ptr,
 613                 int *loglevel, struct btr_node *parent, struct btr_node *child,
 614                 struct sched *sched)
 615 {
 616         int ret = client_parse_config(argc, argv, ct_ptr, loglevel);
 617
 618         if (ret < 0)
 619                 return ret;
 620         if (ret == 0) {
 621                 ret = -E_CLIENT_SYNTAX;
 622                 goto fail;
 623         }
 624         ret = client_connect(*ct_ptr, sched, parent, child);
 625         if (ret < 0)
 626                 goto fail;
 627         return 1;
 628 fail:
 629         client_close(*ct_ptr);
 630         *ct_ptr = NULL;
 631         return ret;
 632 }