client_common.c

   1 /* Copyright (C) 1997 Andre Noll <maan@tuebingen.mpg.de>, see file COPYING. */
   2
   3 /** \file client_common.c Common functions of para_client and para_audiod. */
   4
   5 #include <netinet/in.h>
   6 #include <sys/socket.h>
   7 #include <regex.h>
   8 #include <sys/types.h>
   9 #include <arpa/inet.h>
  10 #include <sys/un.h>
  11 #include <netdb.h>
  12 #include <lopsub.h>
  13
  14 #include "client.lsg.h"
  15 #include "para.h"
  16 #include "error.h"
  17 #include "list.h"
  18 #include "lsu.h"
  19 #include "sched.h"
  20 #include "crypt.h"
  21 #include "net.h"
  22 #include "fd.h"
  23 #include "sideband.h"
  24 #include "string.h"
  25 #include "client.h"
  26 #include "buffer_tree.h"
  27 #include "version.h"
  28
  29 /** The size of the receiving buffer. */
  30 #define CLIENT_BUFSIZE 4000
  31
  32 /**
  33  * Close the connection to para_server and free all resources.
  34  *
  35  * \param ct Pointer to the client data.
  36  *
  37  * \sa \ref client_open().
  38  */
  39 void client_close(struct client_task *ct)
  40 {
  41         if (!ct)
  42                 return;
  43         free(ct->user);
  44         free(ct->key_file);
  45         lls_free_parse_result(ct->lpr, CLIENT_CMD_PTR);
  46         free(ct->challenge_hash);
  47         sb_free(ct->sbc[0]);
  48         sb_free(ct->sbc[1]);
  49         free(ct);
  50 }
  51
  52 /*
  53  * This function asks the scheduler to monitor a file descriptor which
  54  * corresponds to an active connection. The descriptor is monitored for either
  55  * reading or writing, depending on the state of the connection.
  56  *
  57  * The context pointer is assumed to refer to a client task structure that was
  58  * initialized earlier by client_open().
  59  */
  60 static void client_pre_select(struct sched *s, void *context)
  61 {
  62         int ret;
  63         struct client_task *ct = context;
  64
  65         if (ct->scc.fd < 0)
  66                 return;
  67         switch (ct->status) {
  68         case CL_CONNECTED:
  69         case CL_SENT_AUTH:
  70         case CL_SENT_CH_RESPONSE:
  71                 para_fd_set(ct->scc.fd, &s->rfds, &s->max_fileno);
  72                 return;
  73
  74         case CL_RECEIVED_WELCOME:
  75         case CL_RECEIVED_PROCEED:
  76         case CL_RECEIVED_CHALLENGE:
  77                 para_fd_set(ct->scc.fd, &s->wfds, &s->max_fileno);
  78                 return;
  79
  80         case CL_SENDING:
  81                 if (ct->btrn[1]) {
  82                         ret = btr_node_status(ct->btrn[1], 0, BTR_NT_LEAF);
  83                         if (ret < 0)
  84                                 sched_min_delay(s);
  85                         else if (ret > 0)
  86                                 para_fd_set(ct->scc.fd, &s->wfds, &s->max_fileno);
  87                 }
  88                 __attribute__ ((fallthrough));
  89         case CL_EXECUTING:
  90                 if (ct->btrn[0]) {
  91                         ret = btr_node_status(ct->btrn[0], 0, BTR_NT_ROOT);
  92                         if (ret < 0)
  93                                 sched_min_delay(s);
  94                         else if (ret > 0)
  95                                 para_fd_set(ct->scc.fd, &s->rfds, &s->max_fileno);
  96                 }
  97                 return;
  98         }
  99 }
 100
 101 static int send_sb(struct client_task *ct, int channel, void *buf, size_t numbytes,
 102                 enum sb_designator band, bool dont_free)
 103 {
 104         int ret, fd = ct->scc.fd;
 105         struct iovec iov[2];
 106
 107         if (!ct->sbc[channel]) {
 108                 struct sb_buffer sbb;
 109                 sb_transformation trafo = ct->status < CL_RECEIVED_PROCEED?
 110                         NULL : sc_trafo;
 111                 sbb = (typeof(sbb))SBB_INIT(band, buf, numbytes);
 112                 ct->sbc[channel] = sb_new_send(&sbb, dont_free, trafo, ct->scc.send);
 113         }
 114         ret = sb_get_send_buffers(ct->sbc[channel], iov);
 115         ret = xwritev(fd, iov, ret);
 116         if (ret < 0) {
 117                 sb_free(ct->sbc[channel]);
 118                 ct->sbc[channel] = NULL;
 119                 return ret;
 120         }
 121         if (sb_sent(ct->sbc[channel], ret)) {
 122                 ct->sbc[channel] = NULL;
 123                 return 1;
 124         }
 125         return 0;
 126 }
 127
 128 static int recv_sb(struct client_task *ct, fd_set *rfds,
 129                 struct sb_buffer *result)
 130 {
 131         int ret;
 132         size_t n;
 133         sb_transformation trafo;
 134         void *trafo_context;
 135         struct iovec iov;
 136
 137         if (!FD_ISSET(ct->scc.fd, rfds))
 138                 return 0;
 139         if (ct->status < CL_SENT_CH_RESPONSE)
 140                 trafo = trafo_context = NULL;
 141         else {
 142                 trafo = sc_trafo;
 143                 trafo_context = ct->scc.recv;
 144         }
 145         if (!ct->sbc[0])
 146                 ct->sbc[0] = sb_new_recv(0, trafo, trafo_context);
 147 again:
 148         sb_get_recv_buffer(ct->sbc[0], &iov);
 149         ret = read_nonblock(ct->scc.fd, iov.iov_base, iov.iov_len, rfds, &n);
 150         if (ret < 0) {
 151                 sb_free(ct->sbc[0]);
 152                 ct->sbc[0] = NULL;
 153                 return ret;
 154         }
 155         if (n == 0)
 156                 return 0;
 157         ret = sb_received(ct->sbc[0], n, result);
 158         if (ret < 0)
 159                 return ret;
 160         if (ret == 0)
 161                 goto again;
 162         ct->sbc[0] = NULL;
 163         return 1;
 164 }
 165
 166
 167 static char **parse_features(char *buf)
 168 {
 169         int i;
 170         const char id[] = "\nFeatures: ";
 171         char *p, *q, **features;
 172
 173         p = strstr(buf, id);
 174         if (!p)
 175                 return NULL;
 176         p += strlen(id);
 177         q = strchr(p, '\n');
 178         if (!q)
 179                 return NULL;
 180         *q = '\0';
 181         create_argv(p, ",", &features);
 182         for (i = 0; features[i]; i++)
 183                 PARA_INFO_LOG("server feature: %s\n", features[i]);
 184         return features;
 185 }
 186
 187 static int dispatch_sbb(struct client_task *ct, struct sb_buffer *sbb)
 188 {
 189         int ret;
 190         const char *designator[] = {SB_DESIGNATORS_ARRAY};
 191
 192         if (!sbb)
 193                 return 0;
 194         if (sbb->band < NUM_SB_DESIGNATORS)
 195                 PARA_DEBUG_LOG("band: %s\n", designator[sbb->band]);
 196
 197         switch (sbb->band) {
 198         case SBD_AWAITING_DATA:
 199                 ct->status = CL_SENDING;
 200                 ret = 1;
 201                 goto out;
 202         case SBD_OUTPUT:
 203                 if (iov_valid(&sbb->iov))
 204                         btr_add_output(sbb->iov.iov_base, sbb->iov.iov_len,
 205                                 ct->btrn[0]);
 206                 ret = 1;
 207                 goto out;
 208         case SBD_DEBUG_LOG:
 209         case SBD_INFO_LOG:
 210         case SBD_NOTICE_LOG:
 211         case SBD_WARNING_LOG:
 212         case SBD_ERROR_LOG:
 213         case SBD_CRIT_LOG:
 214         case SBD_EMERG_LOG:
 215                 if (iov_valid(&sbb->iov)) {
 216                         int ll = sbb->band - SBD_DEBUG_LOG;
 217                         para_log(ll, "remote: %s", (char *)sbb->iov.iov_base);
 218                 }
 219                 ret = 1;
 220                 goto deallocate;
 221         case SBD_EXIT__SUCCESS:
 222                 ret = -E_SERVER_CMD_SUCCESS;
 223                 goto deallocate;
 224         case SBD_EXIT__FAILURE:
 225                 ret = -E_SERVER_CMD_FAILURE;
 226                 goto deallocate;
 227         default:
 228                 PARA_ERROR_LOG("invalid band %d\n", sbb->band);
 229                 ret = -E_BAD_BAND;
 230                 goto deallocate;
 231         }
 232 deallocate:
 233         free(sbb->iov.iov_base);
 234 out:
 235         sbb->iov.iov_base = NULL;
 236         return ret;
 237 }
 238
 239 static int send_sb_command(struct client_task *ct)
 240 {
 241         int i;
 242         char *command, *p;
 243         size_t len = 0;
 244         unsigned num_inputs = lls_num_inputs(ct->lpr);
 245
 246         if (ct->sbc[1])
 247                 return send_sb(ct, 0, NULL, 0, 0, false);
 248
 249         for (i = 0; i < num_inputs; i++)
 250                 len += strlen(lls_input(i, ct->lpr)) + 1;
 251         p = command = para_malloc(len);
 252         for (i = 0; i < num_inputs; i++) {
 253                 const char *str = lls_input(i, ct->lpr);
 254                 strcpy(p, str);
 255                 p += strlen(str) + 1;
 256         }
 257         PARA_DEBUG_LOG("--> %s\n", command);
 258         return send_sb(ct, 0, command, len, SBD_COMMAND, false);
 259 }
 260
 261 /*
 262  * This function reads or writes to the socket file descriptor which
 263  * corresponds to an established connection between the client and the server.
 264  * It depends on the current state of the connection and on the readiness of
 265  * the socket file descriptor which type of I/O is going to be performed.
 266  * Besides the initial handshake and authentication, the function sends the
 267  * server command and receives the output from the server, if any.
 268  *
 269  * The context pointer refers to a client task structure that was initialized
 270  * earlier by client_open().
 271  */
 272 static int client_post_select(struct sched *s, void *context)
 273 {
 274         struct client_task *ct = context;
 275         int ret = 0;
 276         size_t n;
 277         char buf[CLIENT_BUFSIZE];
 278
 279         ret = task_get_notification(ct->task);
 280         if (ret < 0)
 281                 goto out;
 282         if (ct->scc.fd < 0)
 283                 return 0;
 284         switch (ct->status) {
 285         case CL_CONNECTED: /* receive welcome message */
 286                 ret = read_nonblock(ct->scc.fd, buf, sizeof(buf), &s->rfds, &n);
 287                 if (ret < 0 || n == 0)
 288                         goto out;
 289                 ct->features = parse_features(buf);
 290                 ct->status = CL_RECEIVED_WELCOME;
 291                 return 0;
 292         case CL_RECEIVED_WELCOME: /* send auth command */
 293                 if (!FD_ISSET(ct->scc.fd, &s->wfds))
 294                         return 0;
 295                 sprintf(buf, AUTH_REQUEST_MSG "%s sideband,aes_ctr128",
 296                         ct->user);
 297                 PARA_INFO_LOG("--> %s\n", buf);
 298                 ret = write_buffer(ct->scc.fd, buf);
 299                 if (ret < 0)
 300                         goto out;
 301                 ct->status = CL_SENT_AUTH;
 302                 return 0;
 303         case CL_SENT_AUTH:
 304                 /*
 305                  * Receive challenge and session keys, decrypt the challenge and
 306                  * send back the hash of the decrypted challenge.
 307                  */
 308                 {
 309                 /* decrypted challenge/session key buffer */
 310                 unsigned char crypt_buf[1024];
 311                 struct sb_buffer sbb;
 312
 313                 ret = recv_sb(ct, &s->rfds, &sbb);
 314                 if (ret <= 0)
 315                         goto out;
 316                 if (sbb.band != SBD_CHALLENGE) {
 317                         ret = -E_BAD_BAND;
 318                         free(sbb.iov.iov_base);
 319                                 goto out;
 320                 }
 321                 n = sbb.iov.iov_len;
 322                 PARA_INFO_LOG("<-- [challenge] (%zu bytes)\n", n);
 323                 ret = apc_priv_decrypt(ct->key_file, crypt_buf,
 324                         sbb.iov.iov_base, n);
 325                 free(sbb.iov.iov_base);
 326                 if (ret < 0)
 327                         goto out;
 328                 ct->challenge_hash = para_malloc(HASH_SIZE);
 329                 hash_function((char *)crypt_buf, APC_CHALLENGE_SIZE, ct->challenge_hash);
 330                 ct->scc.send = sc_new(crypt_buf + APC_CHALLENGE_SIZE, SESSION_KEY_LEN);
 331                 ct->scc.recv = sc_new(crypt_buf + APC_CHALLENGE_SIZE + SESSION_KEY_LEN,
 332                         SESSION_KEY_LEN);
 333                 hash_to_asc(ct->challenge_hash, buf);
 334                 PARA_INFO_LOG("--> %s\n", buf);
 335                 ct->status = CL_RECEIVED_CHALLENGE;
 336                 return 0;
 337                 }
 338         case CL_RECEIVED_CHALLENGE:
 339                 ret = send_sb(ct, 0, ct->challenge_hash, HASH_SIZE,
 340                         SBD_CHALLENGE_RESPONSE, false);
 341                 if (ret != 0)
 342                         ct->challenge_hash = NULL;
 343                 if (ret <= 0)
 344                         goto out;
 345                 ct->status = CL_SENT_CH_RESPONSE;
 346                 goto out;
 347         case CL_SENT_CH_RESPONSE: /* read server response */
 348                 {
 349                 struct sb_buffer sbb;
 350                 ret = recv_sb(ct, &s->rfds, &sbb);
 351                 if (ret <= 0)
 352                         goto out;
 353                 free(sbb.iov.iov_base);
 354                 if (sbb.band != SBD_PROCEED)
 355                         ret = -E_BAD_BAND;
 356                 else
 357                         ct->status = CL_RECEIVED_PROCEED;
 358                 goto out;
 359                 }
 360         case CL_RECEIVED_PROCEED: /* concat args and send command */
 361                 {
 362                 if (!FD_ISSET(ct->scc.fd, &s->wfds))
 363                         return 0;
 364                 ret = send_sb_command(ct);
 365                 if (ret <= 0)
 366                         goto out;
 367                 ct->status = CL_EXECUTING;
 368                 return 0;
 369                 }
 370         case CL_SENDING:
 371                 if (ct->btrn[1]) {
 372                         char *buf2;
 373                         size_t sz;
 374                         ret = btr_node_status(ct->btrn[1], 0, BTR_NT_LEAF);
 375                         if (ret == -E_BTR_EOF) {
 376                                 /* empty blob data packet indicates EOF */
 377                                 PARA_INFO_LOG("blob sent\n");
 378                                 ret = send_sb(ct, 1, NULL, 0, SBD_BLOB_DATA, true);
 379                                 if (ret >= 0)
 380                                         ret = -E_BTR_EOF;
 381                         }
 382                         if (ret < 0)
 383                                 goto close1;
 384                         if (ret > 0 && FD_ISSET(ct->scc.fd, &s->wfds)) {
 385                                 sz = btr_next_buffer(ct->btrn[1], &buf2);
 386                                 assert(sz);
 387                                 ret = send_sb(ct, 1, buf2, sz, SBD_BLOB_DATA, true);
 388                                 if (ret < 0)
 389                                         goto close1;
 390                                 if (ret > 0)
 391                                         btr_consume(ct->btrn[1], sz);
 392                         }
 393                 }
 394                 __attribute__ ((fallthrough));
 395         case CL_EXECUTING:
 396                 if (ct->btrn[0]) {
 397                         ret = btr_node_status(ct->btrn[0], 0, BTR_NT_ROOT);
 398                         if (ret < 0)
 399                                 goto close0;
 400                         if (ret > 0 && FD_ISSET(ct->scc.fd, &s->rfds)) {
 401                                 struct sb_buffer sbb;
 402                                 ret = recv_sb(ct, &s->rfds, &sbb);
 403                                 if (ret < 0)
 404                                         goto close0;
 405                                 if (ret > 0) {
 406                                         ret = dispatch_sbb(ct, &sbb);
 407                                         if (ret < 0)
 408                                                 goto close0;
 409                                 }
 410                         }
 411                 }
 412                 ret = 0;
 413                 goto out;
 414         }
 415 close1:
 416         PARA_INFO_LOG("channel 1: %s\n", para_strerror(-ret));
 417         btr_remove_node(&ct->btrn[1]);
 418         if (ct->btrn[0])
 419                 return 0;
 420         goto out;
 421 close0:
 422         PARA_INFO_LOG("channel 0: %s\n", para_strerror(-ret));
 423         btr_remove_node(&ct->btrn[0]);
 424         if (ct->btrn[1] && ct->status == CL_SENDING)
 425                 return 0;
 426 out:
 427         if (ret >= 0)
 428                 return 0;
 429         btr_remove_node(&ct->btrn[0]);
 430         btr_remove_node(&ct->btrn[1]);
 431         if (ret != -E_SERVER_CMD_SUCCESS && ret != -E_SERVER_CMD_FAILURE)
 432                 PARA_ERROR_LOG("%s\n", para_strerror(-ret));
 433         if (ct->scc.fd >= 0) {
 434                 close(ct->scc.fd);
 435                 ct->scc.fd = -1;
 436         }
 437         free_argv(ct->features);
 438         ct->features = NULL;
 439         sc_free(ct->scc.recv);
 440         ct->scc.recv = NULL;
 441         sc_free(ct->scc.send);
 442         ct->scc.send = NULL;
 443         return ret;
 444 }
 445
 446 /**
 447  * Connect to para_server and register the client task.
 448  *
 449  * \param ct The initialized client task structure.
 450  * \param s The scheduler instance to register the client task to.
 451  * \param parent The parent node of the client btr node.
 452  * \param child The child node of the client node.
 453  *
 454  * The client task structure given by \a ct  must be allocated and initialized
 455  * by \ref client_parse_config() before this function is called.
 456  *
 457  * \return Standard.
 458  */
 459 int client_connect(struct client_task *ct, struct sched *s,
 460                 struct btr_node *parent, struct btr_node *child)
 461 {
 462         int ret;
 463         const char *host = CLIENT_OPT_STRING_VAL(HOSTNAME, ct->lpr);
 464         uint32_t port = CLIENT_OPT_UINT32_VAL(SERVER_PORT, ct->lpr);
 465
 466         PARA_NOTICE_LOG("connecting %s:%u\n", host, port);
 467         ct->scc.fd = -1;
 468         ret = para_connect_simple(IPPROTO_TCP, host, port);
 469         if (ret < 0)
 470                 return ret;
 471         ct->scc.fd = ret;
 472         ret = mark_fd_nonblocking(ct->scc.fd);
 473         if (ret < 0)
 474                 goto err_out;
 475         ct->status = CL_CONNECTED;
 476         ct->btrn[0] = btr_new_node(&(struct btr_node_description)
 477                 EMBRACE(.name = "client recv", .parent = NULL, .child = child));
 478         ct->btrn[1] = btr_new_node(&(struct btr_node_description)
 479                 EMBRACE(.name = "client send", .parent = parent, .child = NULL));
 480
 481         ct->task = task_register(&(struct task_info) {
 482                 .name = "client",
 483                 .pre_select = client_pre_select,
 484                 .post_select = client_post_select,
 485                 .context = ct,
 486         }, s);
 487         return 1;
 488 err_out:
 489         close(ct->scc.fd);
 490         ct->scc.fd = -1;
 491         return ret;
 492 }
 493
 494 static void handle_help_flag(struct lls_parse_result *lpr)
 495 {
 496         char *help;
 497
 498         if (CLIENT_OPT_GIVEN(DETAILED_HELP, lpr))
 499                 help = lls_long_help(CLIENT_CMD_PTR);
 500         else if (CLIENT_OPT_GIVEN(HELP, lpr))
 501                 help = lls_short_help(CLIENT_CMD_PTR);
 502         else
 503                 return;
 504         printf("%s\n", help);
 505         free(help);
 506         exit(EXIT_SUCCESS);
 507 }
 508
 509 /**
 510  * Parse a client configuration.
 511  *
 512  * \param argc Usual argument count.
 513  * \param argv Usual argument vector.
 514  * \param ct_ptr Filled in by this function.
 515  * \param loglevel If not \p NULL, the number of the loglevel is stored here.
 516  *
 517  * This checks the command line options given by \a argc and \a argv, sets
 518  * default values for the user name and the name of the rsa key file and reads
 519  * further options from the config file.
 520  *
 521  * Upon successful return, \a ct_ptr points to a dynamically allocated and
 522  * initialized client task struct.
 523  *
 524  * \return The number of non-option arguments in \a argc/argv on success,
 525  * negative on errors.
 526  */
 527 int client_parse_config(int argc, char *argv[], struct client_task **ct_ptr,
 528                 int *loglevel)
 529 {
 530         const struct lls_command *cmd = CLIENT_CMD_PTR;
 531         struct lls_parse_result *lpr;
 532         int ret, ll;
 533         struct client_task *ct;
 534         char *kf = NULL, *user, *errctx, *home = para_homedir();
 535
 536         ret = lls(lls_parse(argc, argv, cmd, &lpr, &errctx));
 537         if (ret < 0)
 538                 goto out;
 539         version_handle_flag("client", CLIENT_OPT_GIVEN(VERSION, lpr));
 540         handle_help_flag(lpr);
 541
 542         ret = lsu_merge_config_file_options(CLIENT_OPT_STRING_VAL(CONFIG_FILE, lpr),
 543                 "client.conf", &lpr, cmd, client_suite, 0U /* default flags */);
 544         if (ret < 0)
 545                 goto out;
 546         /* success */
 547         ll = CLIENT_OPT_UINT32_VAL(LOGLEVEL, lpr);
 548         if (loglevel)
 549                 *loglevel = ll;
 550         user = CLIENT_OPT_GIVEN(USER, lpr)?
 551                 para_strdup(CLIENT_OPT_STRING_VAL(USER, lpr)) : para_logname();
 552
 553         if (CLIENT_OPT_GIVEN(KEY_FILE, lpr))
 554                 kf = para_strdup(CLIENT_OPT_STRING_VAL(KEY_FILE, lpr));
 555         else {
 556                 kf = make_message("%s/.paraslash/key.%s", home, user);
 557                 if (!file_exists(kf)) {
 558                         free(kf);
 559                         kf = make_message("%s/.ssh/id_rsa", home);
 560                 }
 561         }
 562         PARA_INFO_LOG("user: %s\n", user);
 563         PARA_INFO_LOG("key file: %s\n", kf);
 564         PARA_INFO_LOG("loglevel: %d\n", ll);
 565         ct = para_calloc(sizeof(*ct));
 566         ct->scc.fd = -1;
 567         ct->lpr = lpr;
 568         ct->key_file = kf;
 569         ct->user = user;
 570         *ct_ptr = ct;
 571         ret = lls_num_inputs(lpr);
 572 out:
 573         free(home);
 574         if (ret < 0) {
 575                 if (errctx)
 576                         PARA_ERROR_LOG("%s\n", errctx);
 577                 free(errctx);
 578                 lls_free_parse_result(lpr, cmd);
 579                 free(kf);
 580                 *ct_ptr = NULL;
 581         }
 582         return ret;
 583 }
 584
 585 /**
 586  * Parse the client configuration and open a connection to para_server.
 587  *
 588  * \param argc See \ref client_parse_config.
 589  * \param argv See \ref client_parse_config.
 590  * \param ct_ptr See \ref client_parse_config.
 591  * \param loglevel See \ref client_parse_config.
 592  * \param parent See \ref client_connect().
 593  * \param child See \ref client_connect().
 594  * \param sched See \ref client_connect().
 595  *
 596  * This function combines client_parse_config() and client_connect(). It is
 597  * considered a syntax error if no command was given, i.e. if the number
 598  * of non-option arguments is zero.
 599  *
 600  * \return Standard.
 601  */
 602 int client_open(int argc, char *argv[], struct client_task **ct_ptr,
 603                 int *loglevel, struct btr_node *parent, struct btr_node *child,
 604                 struct sched *sched)
 605 {
 606         int ret = client_parse_config(argc, argv, ct_ptr, loglevel);
 607
 608         if (ret < 0)
 609                 return ret;
 610         if (ret == 0) {
 611                 ret = -E_CLIENT_SYNTAX;
 612                 goto fail;
 613         }
 614         ret = client_connect(*ct_ptr, sched, parent, child);
 615         if (ret < 0)
 616                 goto fail;
 617         return 1;
 618 fail:
 619         client_close(*ct_ptr);
 620         *ct_ptr = NULL;
 621         return ret;
 622 }