Use sideband also for "proceed" handshake.
[paraslash.git] / client_common.c
1 /*
2 * Copyright (C) 1997-2012 Andre Noll <maan@systemlinux.org>
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 <regex.h>
10 #include <sys/types.h>
11
12 #include "para.h"
13 #include "error.h"
14 #include "list.h"
15 #include "sched.h"
16 #include "client.cmdline.h"
17 #include "crypt.h"
18 #include "net.h"
19 #include "fd.h"
20 #include "sideband.h"
21 #include "string.h"
22 #include "client.cmdline.h"
23 #include "client.h"
24 #include "buffer_tree.h"
25 #include "version.h"
26
27 /** The size of the receiving buffer. */
28 #define CLIENT_BUFSIZE 4000
29
30 /**
31 * Close the connection to para_server and deallocate per-command ressources.
32 *
33 * \param ct The client task.
34 *
35 * This frees all ressources of the current command but keeps the configuration
36 * in \p ct->conf.
37 *
38 * \sa \ref client_close().
39 */
40 void client_disconnect(struct client_task *ct)
41 {
42 if (!ct)
43 return;
44 if (ct->scc.fd >= 0)
45 close(ct->scc.fd);
46 free_argv(ct->features);
47 sc_free(ct->scc.recv);
48 ct->scc.recv = NULL;
49 sc_free(ct->scc.send);
50 ct->scc.send = NULL;
51 btr_free_node(ct->btrn);
52 ct->btrn = NULL;
53 }
54
55 /**
56 * Close the connection to para_server and free all resources.
57 *
58 * \param ct Pointer to the client data.
59 *
60 * \sa \ref client_open(), \ref client_disconnect().
61 */
62 void client_close(struct client_task *ct)
63 {
64 if (!ct)
65 return;
66 client_disconnect(ct);
67 free(ct->user);
68 free(ct->config_file);
69 free(ct->key_file);
70 client_cmdline_parser_free(&ct->conf);
71 free(ct->challenge_hash);
72 sb_free(ct->sbc);
73 free(ct);
74 }
75
76 /**
77 * The preselect hook for server commands.
78 *
79 * \param s Pointer to the scheduler.
80 * \param t Pointer to the task struct for this command.
81 *
82 * The task pointer must contain a pointer to the initialized client data
83 * structure as it is returned by client_open().
84 *
85 * This function checks the state of the connection and adds the file descriptor
86 * of the connection to the read or write fd set of \a s accordingly.
87 *
88 * \sa register_task() client_open(), struct sched, struct task.
89 */
90 static void client_pre_select(struct sched *s, struct task *t)
91 {
92 int ret;
93 struct client_task *ct = container_of(t, struct client_task, task);
94 struct btr_node *btrn = ct->btrn;
95
96 if (ct->scc.fd < 0)
97 return;
98 switch (ct->status) {
99 case CL_CONNECTED:
100 case CL_SENT_AUTH:
101 case CL_SENT_CH_RESPONSE:
102 case CL_SENT_COMMAND:
103 para_fd_set(ct->scc.fd, &s->rfds, &s->max_fileno);
104 return;
105
106 case CL_RECEIVED_WELCOME:
107 case CL_RECEIVED_PROCEED:
108 case CL_RECEIVED_CHALLENGE:
109 para_fd_set(ct->scc.fd, &s->wfds, &s->max_fileno);
110 return;
111
112 case CL_RECEIVING:
113 ret = btr_node_status(btrn, 0, BTR_NT_ROOT);
114 if (ret != 0) {
115 if (ret < 0)
116 sched_min_delay(s);
117 else
118 para_fd_set(ct->scc.fd, &s->rfds,
119 &s->max_fileno);
120 }
121 return;
122 case CL_SENDING:
123 ret = btr_node_status(btrn, 0, BTR_NT_LEAF);
124 if (ret != 0) {
125 if (ret < 0)
126 sched_min_delay(s);
127 else
128 para_fd_set(ct->scc.fd, &s->wfds,
129 &s->max_fileno);
130 }
131 return;
132 }
133 }
134
135 static int client_recv_buffer(struct client_task *ct, fd_set *rfds,
136 char *buf, size_t sz, size_t *n)
137 {
138 int ret;
139
140 if (ct->status < CL_SENT_CH_RESPONSE)
141 return read_nonblock(ct->scc.fd, buf, sz, rfds, n);
142
143 *n = 0;
144 ret = sc_recv_buffer(&ct->scc, buf, sz);
145 /*
146 * sc_recv_buffer is used with blocking fds elsewhere, so it
147 * does not use the nonblock-API. Therefore we need to
148 * check for EOF and EAGAIN.
149 */
150 if (ret == 0)
151 return -E_SERVER_EOF;
152 if (ret == -ERRNO_TO_PARA_ERROR(EAGAIN))
153 return 0;
154 if (ret < 0)
155 return ret;
156 *n = ret;
157 return 0;
158 }
159
160 static int send_sb(struct client_task *ct, void *buf, size_t numbytes,
161 enum sb_designator band, bool dont_free)
162 {
163 int ret, fd = ct->scc.fd;
164 struct iovec iov[2];
165
166 if (!ct->sbc) {
167 struct sb_buffer sbb;
168 sb_transformation trafo = ct->status < CL_RECEIVED_PROCEED?
169 NULL : sc_trafo;
170 sbb = (typeof(sbb))SBB_INIT(band, buf, numbytes);
171 ct->sbc = sb_new_send(&sbb, dont_free, trafo, ct->scc.send);
172 }
173 ret = sb_get_send_buffers(ct->sbc, iov);
174 ret = xwritev(fd, iov, ret);
175 if (ret < 0) {
176 sb_free(ct->sbc);
177 ct->sbc = NULL;
178 return ret;
179 }
180 if (sb_sent(ct->sbc, ret)) {
181 ct->sbc = NULL;
182 return 1;
183 }
184 return 0;
185 }
186
187 static int recv_sb(struct client_task *ct, fd_set *rfds,
188 struct sb_buffer *result)
189 {
190 int ret;
191 size_t n;
192 sb_transformation trafo;
193 void *trafo_context;
194 struct iovec iov;
195
196 if (!FD_ISSET(ct->scc.fd, rfds))
197 return 0;
198 if (ct->status < CL_SENT_CH_RESPONSE)
199 trafo = trafo_context = NULL;
200 else {
201 trafo = sc_trafo;
202 trafo_context = ct->scc.recv;
203 }
204 if (!ct->sbc)
205 ct->sbc = sb_new_recv(0, trafo, trafo_context);
206 again:
207 sb_get_recv_buffer(ct->sbc, &iov);
208 ret = read_nonblock(ct->scc.fd, iov.iov_base, iov.iov_len, rfds, &n);
209 if (ret < 0) {
210 sb_free(ct->sbc);
211 ct->sbc = NULL;
212 return ret;
213 }
214 if (n == 0)
215 return 0;
216 if (!sb_received(ct->sbc, n, result))
217 goto again;
218 ct->sbc = NULL;
219 return 1;
220 }
221
222
223 static char **parse_features(char *buf)
224 {
225 int i;
226 const char id[] = "\nFeatures: ";
227 char *p, *q, **features;
228
229 p = strstr(buf, id);
230 if (!p)
231 return NULL;
232 p += strlen(id);
233 q = strchr(p, '\n');
234 if (!q)
235 return NULL;
236 *q = '\0';
237 create_argv(p, ",", &features);
238 for (i = 0; features[i]; i++)
239 PARA_INFO_LOG("server feature: %s\n", features[i]);
240 return features;
241 }
242
243 static bool has_feature(const char *feature, struct client_task *ct)
244 {
245 return find_arg(feature, ct->features) >= 0? true : false;
246 }
247
248 /**
249 * The post select hook for client commands.
250 *
251 * \param s Pointer to the scheduler.
252 * \param t Pointer to the task struct for this command.
253 *
254 * Depending on the current state of the connection and the status of the read
255 * and write fd sets of \a s, this function performs the necessary steps to
256 * authenticate the connection, to send the command given by \a t->private_data
257 * and to receive para_server's output, if any.
258 *
259 * \sa struct sched, struct task.
260 */
261 static void client_post_select(struct sched *s, struct task *t)
262 {
263 struct client_task *ct = container_of(t, struct client_task, task);
264 struct btr_node *btrn = ct->btrn;
265 int ret = 0;
266 size_t n;
267 char buf[CLIENT_BUFSIZE];
268
269 t->error = 0;
270 if (ct->scc.fd < 0)
271 return;
272 switch (ct->status) {
273 case CL_CONNECTED: /* receive welcome message */
274 ret = client_recv_buffer(ct, &s->rfds, buf, sizeof(buf), &n);
275 if (ret < 0 || n == 0)
276 goto out;
277 ct->features = parse_features(buf);
278 ct->status = CL_RECEIVED_WELCOME;
279 return;
280 case CL_RECEIVED_WELCOME: /* send auth command */
281 if (!FD_ISSET(ct->scc.fd, &s->wfds))
282 return;
283 if (has_feature("sideband", ct)) {
284 ct->use_sideband = true;
285 sprintf(buf, AUTH_REQUEST_MSG "%s sideband", ct->user);
286 } else
287 sprintf(buf, AUTH_REQUEST_MSG "%s", ct->user);
288 PARA_INFO_LOG("--> %s\n", buf);
289 ret = write_buffer(ct->scc.fd, buf);
290 if (ret < 0)
291 goto out;
292 ct->status = CL_SENT_AUTH;
293 return;
294 case CL_SENT_AUTH:
295 /*
296 * Receive challenge and session keys, decrypt the challenge and
297 * send back the hash of the decrypted challenge.
298 */
299 {
300 /* decrypted challenge/session key buffer */
301 unsigned char crypt_buf[1024];
302 /* the SHA1 of the decrypted challenge */
303
304 if (ct->use_sideband) {
305 struct sb_buffer sbb;
306 ret = recv_sb(ct, &s->rfds, &sbb);
307 if (ret <= 0)
308 goto out;
309 if (sbb.band != SBD_CHALLENGE) {
310 ret = -E_BAD_BAND;
311 free(sbb.iov.iov_base);
312 goto out;
313 }
314 n = sbb.iov.iov_len;
315 PARA_INFO_LOG("<-- [challenge] (%zu bytes)\n", n);
316 ret = priv_decrypt(ct->key_file, crypt_buf,
317 sbb.iov.iov_base, n);
318 free(sbb.iov.iov_base);
319 if (ret < 0)
320 goto out;
321 } else {
322 ret = client_recv_buffer(ct, &s->rfds, buf, sizeof(buf), &n);
323 if (ret < 0 || n == 0)
324 goto out;
325 PARA_INFO_LOG("<-- [challenge] (%zu bytes)\n", n);
326 ret = priv_decrypt(ct->key_file, crypt_buf,
327 (unsigned char *)buf, n);
328 if (ret < 0)
329 goto out;
330 }
331 ct->challenge_hash = para_malloc(HASH_SIZE);
332 hash_function((char *)crypt_buf, CHALLENGE_SIZE, ct->challenge_hash);
333 ct->scc.send = sc_new(crypt_buf + CHALLENGE_SIZE, SESSION_KEY_LEN);
334 ct->scc.recv = sc_new(crypt_buf + CHALLENGE_SIZE + SESSION_KEY_LEN,
335 SESSION_KEY_LEN);
336 hash_to_asc(ct->challenge_hash, buf);
337 PARA_INFO_LOG("--> %s\n", buf);
338 ct->status = CL_RECEIVED_CHALLENGE;
339 return;
340 }
341 case CL_RECEIVED_CHALLENGE:
342 if (ct->use_sideband) {
343 ret = send_sb(ct, ct->challenge_hash, HASH_SIZE,
344 SBD_CHALLENGE_RESPONSE, false);
345 if (ret != 0)
346 ct->challenge_hash = NULL;
347 if (ret <= 0)
348 goto out;
349 } else {
350 ret = write_all(ct->scc.fd, (char *)ct->challenge_hash, HASH_SIZE);
351 if (ret < 0)
352 goto out;
353 }
354 ct->status = CL_SENT_CH_RESPONSE;
355 goto out;
356 case CL_SENT_CH_RESPONSE: /* read server response */
357 {
358 if (ct->use_sideband) {
359 struct sb_buffer sbb;
360 ret = recv_sb(ct, &s->rfds, &sbb);
361 if (ret <= 0)
362 goto out;
363 free(sbb.iov.iov_base);
364 if (sbb.band != SBD_PROCEED)
365 ret = -E_BAD_BAND;
366 else
367 ct->status = CL_RECEIVED_PROCEED;
368 goto out;
369 }
370 ret = client_recv_buffer(ct, &s->rfds, buf, sizeof(buf), &n);
371 if (ret < 0 || n == 0)
372 goto out;
373 /* check if server has sent "Proceed" message */
374 ret = -E_CLIENT_AUTH;
375 if (n < PROCEED_MSG_LEN)
376 goto out;
377 if (!strstr(buf, PROCEED_MSG))
378 goto out;
379 ct->status = CL_RECEIVED_PROCEED;
380 return;
381 }
382 case CL_RECEIVED_PROCEED: /* concat args and send command */
383 {
384 int i;
385 char *command = NULL;
386 if (!FD_ISSET(ct->scc.fd, &s->wfds))
387 return;
388 for (i = 0; i < ct->conf.inputs_num; i++) {
389 char *tmp = command;
390 command = make_message("%s\n%s", command?
391 command : "", ct->conf.inputs[i]);
392 free(tmp);
393 }
394 command = para_strcat(command, EOC_MSG "\n");
395 PARA_DEBUG_LOG("--> %s\n", command);
396 ret = sc_send_buffer(&ct->scc, command);
397 free(command);
398 if (ret < 0)
399 goto out;
400 ct->status = CL_SENT_COMMAND;
401 return;
402 }
403 case CL_SENT_COMMAND:
404 {
405 char *buf2;
406 /* can not use "buf" here because we need a malloced buffer */
407 buf2 = para_malloc(CLIENT_BUFSIZE);
408 ret = client_recv_buffer(ct, &s->rfds, buf2, CLIENT_BUFSIZE, &n);
409 if (n > 0) {
410 if (strstr(buf2, AWAITING_DATA_MSG)) {
411 free(buf2);
412 ct->status = CL_SENDING;
413 return;
414 }
415 ct->status = CL_RECEIVING;
416 btr_add_output(buf2, n, btrn);
417 } else
418 free(buf2);
419 goto out;
420 }
421 case CL_SENDING:
422 {
423 char *buf2;
424 size_t sz;
425 ret = btr_node_status(btrn, 0, BTR_NT_LEAF);
426 if (ret < 0)
427 goto out;
428 if (ret == 0)
429 return;
430 if (!FD_ISSET(ct->scc.fd, &s->wfds))
431 return;
432 sz = btr_next_buffer(btrn, &buf2);
433 ret = sc_send_bin_buffer(&ct->scc, buf2, sz);
434 if (ret < 0)
435 goto out;
436 btr_consume(btrn, sz);
437 return;
438 }
439 case CL_RECEIVING:
440 {
441 char *buf2;
442 ret = btr_node_status(btrn, 0, BTR_NT_ROOT);
443 if (ret < 0)
444 goto out;
445 if (ret == 0)
446 return;
447 /*
448 * The FD_ISSET() is not strictly necessary, but is allows us
449 * to skip the malloc below if there is nothing to read anyway.
450 */
451 if (!FD_ISSET(ct->scc.fd, &s->rfds))
452 return;
453 buf2 = para_malloc(CLIENT_BUFSIZE);
454 ret = client_recv_buffer(ct, &s->rfds, buf2, CLIENT_BUFSIZE, &n);
455 if (n > 0) {
456 buf2 = para_realloc(buf2, n);
457 btr_add_output(buf2, n, btrn);
458 } else
459 free(buf2);
460 goto out;
461 }
462 }
463 out:
464 t->error = ret;
465 if (ret < 0) {
466 if (ret != -E_SERVER_EOF && ret != -E_BTR_EOF && ret != -E_EOF)
467 PARA_ERROR_LOG("%s\n", para_strerror(-t->error));
468 btr_remove_node(btrn);
469 }
470 }
471
472 /**
473 * Connect to para_server and register the client task.
474 *
475 * \param ct The initialized client task structure.
476 * \param s The scheduler instance to register the client task to.
477 * \param parent The parent node of the client btr node.
478 * \param child The child node of the client node.
479 *
480 * The client task structure given by \a ct must be allocated and initialized
481 * by \ref client_parse_config() before this function is called.
482 *
483 * \return Standard.
484 */
485 int client_connect(struct client_task *ct, struct sched *s,
486 struct btr_node *parent, struct btr_node *child)
487 {
488 int ret;
489
490 PARA_NOTICE_LOG("connecting %s:%d\n", ct->conf.hostname_arg,
491 ct->conf.server_port_arg);
492 ct->scc.fd = -1;
493 ret = para_connect_simple(IPPROTO_TCP, ct->conf.hostname_arg,
494 ct->conf.server_port_arg);
495 if (ret < 0)
496 return ret;
497 ct->scc.fd = ret;
498 ret = mark_fd_nonblocking(ct->scc.fd);
499 if (ret < 0)
500 goto err_out;
501 ct->status = CL_CONNECTED;
502 ct->btrn = btr_new_node(&(struct btr_node_description)
503 EMBRACE(.name = "client", .parent = parent, .child = child));
504 ct->task.pre_select = client_pre_select;
505 ct->task.post_select = client_post_select;
506 ct->task.error = 0;
507 sprintf(ct->task.status, "client");
508 register_task(s, &ct->task);
509 return 1;
510 err_out:
511 close(ct->scc.fd);
512 ct->scc.fd = -1;
513 return ret;
514 }
515
516 /**
517 * Parse a client configuration.
518 *
519 * \param argc Usual argument count.
520 * \param argv Usual argument vector.
521 * \param ct_ptr Filled in by this function.
522 * \param loglevel If not \p NULL, the number of the loglevel is stored here.
523 *
524 * This checks the command line options given by \a argc and \a argv, sets
525 * default values for the user name and the name of the rsa key file and reads
526 * further options from the config file.
527 *
528 * Upon successful return, \a ct_ptr points to a dynamically allocated and
529 * initialized client task struct.
530 *
531 * \return The number of non-option arguments in \a argc/argv on success,
532 * negative on errors.
533 */
534 int client_parse_config(int argc, char *argv[], struct client_task **ct_ptr,
535 int *loglevel)
536 {
537 char *home = para_homedir();
538 int ret;
539 struct client_task *ct = para_calloc(sizeof(struct client_task));
540
541 *ct_ptr = ct;
542 ct->scc.fd = -1;
543 ret = -E_CLIENT_SYNTAX;
544 if (client_cmdline_parser(argc, argv, &ct->conf))
545 goto out;
546 HANDLE_VERSION_FLAG("client", ct->conf);
547
548 ct->config_file = ct->conf.config_file_given?
549 para_strdup(ct->conf.config_file_arg) :
550 make_message("%s/.paraslash/client.conf", home);
551 ret = file_exists(ct->config_file);
552 if (!ret && ct->conf.config_file_given) {
553 ret = -E_NO_CONFIG;
554 goto out;
555 }
556 if (ret) {
557 struct client_cmdline_parser_params params = {
558 .override = 0,
559 .initialize = 0,
560 .check_required = 0,
561 .check_ambiguity = 0,
562 .print_errors = 0
563 };
564 ret = -E_BAD_CONFIG;
565 if (client_cmdline_parser_config_file(ct->config_file,
566 &ct->conf, &params))
567 goto out;
568 }
569 ct->user = ct->conf.user_given?
570 para_strdup(ct->conf.user_arg) : para_logname();
571
572 if (ct->conf.key_file_given)
573 ct->key_file = para_strdup(ct->conf.key_file_arg);
574 else {
575 ct->key_file = make_message("%s/.paraslash/key.%s",
576 home, ct->user);
577 if (!file_exists(ct->key_file)) {
578 free(ct->key_file);
579 ct->key_file = make_message("%s/.ssh/id_rsa", home);
580 }
581 }
582
583 if (loglevel)
584 *loglevel = get_loglevel_by_name(ct->conf.loglevel_arg);
585 PARA_INFO_LOG("loglevel: %s\n", ct->conf.loglevel_arg);
586 PARA_INFO_LOG("config_file: %s\n", ct->config_file);
587 PARA_INFO_LOG("key_file: %s\n", ct->key_file);
588 ret = ct->conf.inputs_num;
589 out:
590 free(home);
591 if (ret < 0) {
592 PARA_ERROR_LOG("%s\n", para_strerror(-ret));
593 client_close(ct);
594 *ct_ptr = NULL;
595 }
596 return ret;
597 }
598
599 /**
600 * Parse the client configuration and open a connection to para_server.
601 *
602 * \param argc See \ref client_parse_config.
603 * \param argv See \ref client_parse_config.
604 * \param ct_ptr See \ref client_parse_config.
605 * \param loglevel See \ref client_parse_config.
606 * \param parent See \ref client_connect().
607 * \param child See \ref client_connect().
608 * \param sched See \ref client_connect().
609 *
610 * This function combines client_parse_config() and client_connect(). It is
611 * considered a syntax error if no command was given, i.e. if the number
612 * of non-option arguments is zero.
613 *
614 * \return Standard.
615 */
616 int client_open(int argc, char *argv[], struct client_task **ct_ptr,
617 int *loglevel, struct btr_node *parent, struct btr_node *child,
618 struct sched *sched)
619 {
620 int ret = client_parse_config(argc, argv, ct_ptr, loglevel);
621
622 if (ret < 0)
623 return ret;
624 if (ret == 0) {
625 ret = -E_CLIENT_SYNTAX;
626 goto fail;
627 }
628 ret = client_connect(*ct_ptr, sched, parent, child);
629 if (ret < 0)
630 goto fail;
631 return 1;
632 fail:
633 client_close(*ct_ptr);
634 *ct_ptr = NULL;
635 return ret;
636 }