Rename struct rc4_context and stream cipher send/receive functions.
[paraslash.git] / client_common.c
1 /*
2 * Copyright (C) 1997-2011 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 #include <dirent.h>
12
13 #include "para.h"
14 #include "error.h"
15 #include "list.h"
16 #include "sched.h"
17 #include "client.cmdline.h"
18 #include "crypt.h"
19 #include "rc4.h"
20 #include "net.h"
21 #include "fd.h"
22 #include "string.h"
23 #include "client.cmdline.h"
24 #include "client.h"
25 #include "hash.h"
26 #include "buffer_tree.h"
27
28 /** The size of the receiving buffer. */
29 #define CLIENT_BUFSIZE 4000
30
31 /**
32 * Close the connection to para_server and free all resources.
33 *
34 * \param ct Pointer to the client data.
35 *
36 * \sa client_open.
37 */
38 void client_close(struct client_task *ct)
39 {
40 if (!ct)
41 return;
42 if (ct->scc.fd >= 0)
43 close(ct->scc.fd);
44 sc_free(ct->scc.recv);
45 sc_free(ct->scc.send);
46 free(ct->user);
47 free(ct->config_file);
48 free(ct->key_file);
49 client_cmdline_parser_free(&ct->conf);
50 free(ct);
51 }
52
53 /**
54 * The preselect hook for server commands.
55 *
56 * \param s Pointer to the scheduler.
57 * \param t Pointer to the task struct for this command.
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 \a s accordingly.
64 *
65 * \sa register_task() client_open(), struct sched, struct task.
66 */
67 static void client_pre_select(struct sched *s, struct task *t)
68 {
69 int ret;
70 struct client_task *ct = container_of(t, struct client_task, task);
71 struct btr_node *btrn = ct->btrn;
72
73 if (ct->scc.fd < 0)
74 return;
75 switch (ct->status) {
76 case CL_CONNECTED:
77 case CL_SENT_AUTH:
78 case CL_SENT_CH_RESPONSE:
79 case CL_SENT_COMMAND:
80 para_fd_set(ct->scc.fd, &s->rfds, &s->max_fileno);
81 return;
82
83 case CL_RECEIVED_WELCOME:
84 case CL_RECEIVED_PROCEED:
85 para_fd_set(ct->scc.fd, &s->wfds, &s->max_fileno);
86 return;
87
88 case CL_RECEIVING:
89 ret = btr_node_status(btrn, 0, BTR_NT_ROOT);
90 if (ret != 0) {
91 if (ret < 0)
92 sched_min_delay(s);
93 else
94 para_fd_set(ct->scc.fd, &s->rfds,
95 &s->max_fileno);
96 }
97 return;
98 case CL_SENDING:
99 ret = btr_node_status(btrn, 0, BTR_NT_LEAF);
100 if (ret != 0) {
101 if (ret < 0)
102 sched_min_delay(s);
103 else
104 para_fd_set(ct->scc.fd, &s->wfds,
105 &s->max_fileno);
106 }
107 return;
108 }
109 }
110
111 static int client_recv_buffer(struct client_task *ct, fd_set *rfds,
112 char *buf, size_t sz, size_t *n)
113 {
114 int ret;
115
116 if (ct->status < CL_SENT_CH_RESPONSE)
117 return read_nonblock(ct->scc.fd, buf, sz, rfds, n);
118
119 *n = 0;
120 ret = sc_recv_buffer(&ct->scc, buf, sz);
121 /*
122 * sc_recv_buffer is used with blocking fds elsewhere, so it
123 * does not use the nonblock-API. Therefore we need to
124 * check for EOF and EAGAIN.
125 */
126 if (ret == 0)
127 return -E_SERVER_EOF;
128 if (ret == -ERRNO_TO_PARA_ERROR(EAGAIN))
129 return 0;
130 if (ret < 0)
131 return ret;
132 *n = ret;
133 return 0;
134 }
135
136 /**
137 * The post select hook for client commands.
138 *
139 * \param s Pointer to the scheduler.
140 * \param t Pointer to the task struct for this command.
141 *
142 * Depending on the current state of the connection and the status of the read
143 * and write fd sets of \a s, this function performs the necessary steps to
144 * authenticate the connection, to send the command given by \a t->private_data
145 * and to receive para_server's output, if any.
146 *
147 * \sa struct sched, struct task.
148 */
149 static void client_post_select(struct sched *s, struct task *t)
150 {
151 struct client_task *ct = container_of(t, struct client_task, task);
152 struct btr_node *btrn = ct->btrn;
153 int ret = 0;
154 size_t n;
155 char buf[CLIENT_BUFSIZE];
156
157 t->error = 0;
158 if (ct->scc.fd < 0)
159 return;
160 switch (ct->status) {
161 case CL_CONNECTED: /* receive welcome message */
162 ret = client_recv_buffer(ct, &s->rfds, buf, sizeof(buf), &n);
163 if (ret < 0 || n == 0)
164 goto out;
165 ct->status = CL_RECEIVED_WELCOME;
166 return;
167 case CL_RECEIVED_WELCOME: /* send auth command */
168 sprintf(buf, AUTH_REQUEST_MSG "%s", ct->user);
169 PARA_INFO_LOG("--> %s\n", buf);
170 if (!FD_ISSET(ct->scc.fd, &s->wfds))
171 return;
172 ret = send_buffer(ct->scc.fd, buf);
173 if (ret < 0)
174 goto out;
175 ct->status = CL_SENT_AUTH;
176 return;
177 case CL_SENT_AUTH:
178 /*
179 * Receive challenge and session keys, decrypt the challenge and
180 * send back the hash of the decrypted challenge.
181 */
182 {
183 /* decrypted challenge/session key buffer */
184 unsigned char crypt_buf[1024];
185 /* the SHA1 of the decrypted challenge */
186 unsigned char challenge_sha1[HASH_SIZE];
187
188 ret = client_recv_buffer(ct, &s->rfds, buf, sizeof(buf), &n);
189 if (ret < 0 || n == 0)
190 goto out;
191 PARA_INFO_LOG("<-- [challenge] (%zu bytes)\n", n);
192 ret = priv_decrypt(ct->key_file, crypt_buf,
193 (unsigned char *)buf, n);
194 if (ret < 0)
195 goto out;
196 sha1_hash((char *)crypt_buf, CHALLENGE_SIZE, challenge_sha1);
197 ct->scc.send = sc_new(crypt_buf + CHALLENGE_SIZE, RC4_KEY_LEN);
198 ct->scc.recv = sc_new(crypt_buf + CHALLENGE_SIZE + RC4_KEY_LEN,
199 RC4_KEY_LEN);
200 hash_to_asc(challenge_sha1, buf);
201 PARA_INFO_LOG("--> %s\n", buf);
202 ret = send_bin_buffer(ct->scc.fd, (char *)challenge_sha1,
203 HASH_SIZE);
204 if (ret < 0)
205 goto out;
206 ct->status = CL_SENT_CH_RESPONSE;
207 return;
208 }
209 case CL_SENT_CH_RESPONSE: /* read server response */
210 {
211 ret = client_recv_buffer(ct, &s->rfds, buf, sizeof(buf), &n);
212 if (ret < 0 || n == 0)
213 goto out;
214 /* check if server has sent "Proceed" message */
215 ret = -E_CLIENT_AUTH;
216 if (n < PROCEED_MSG_LEN)
217 goto out;
218 if (!strstr(buf, PROCEED_MSG))
219 goto out;
220 ct->status = CL_RECEIVED_PROCEED;
221 return;
222 }
223 case CL_RECEIVED_PROCEED: /* concat args and send command */
224 {
225 int i;
226 char *command = NULL;
227 if (!FD_ISSET(ct->scc.fd, &s->wfds))
228 return;
229 for (i = 0; i < ct->conf.inputs_num; i++) {
230 char *tmp = command;
231 command = make_message("%s\n%s", command?
232 command : "", ct->conf.inputs[i]);
233 free(tmp);
234 }
235 command = para_strcat(command, EOC_MSG "\n");
236 PARA_DEBUG_LOG("--> %s\n", command);
237 ret = sc_send_buffer(&ct->scc, command);
238 free(command);
239 if (ret < 0)
240 goto out;
241 ct->status = CL_SENT_COMMAND;
242 return;
243 }
244 case CL_SENT_COMMAND:
245 {
246 char *buf2;
247 /* can not use "buf" here because we need a malloced buffer */
248 buf2 = para_malloc(CLIENT_BUFSIZE);
249 ret = client_recv_buffer(ct, &s->rfds, buf2, CLIENT_BUFSIZE, &n);
250 if (n > 0) {
251 if (strstr(buf2, AWAITING_DATA_MSG)) {
252 free(buf2);
253 ct->status = CL_SENDING;
254 return;
255 }
256 ct->status = CL_RECEIVING;
257 btr_add_output(buf2, n, btrn);
258 } else
259 free(buf2);
260 goto out;
261 }
262 case CL_SENDING:
263 {
264 char *buf2;
265 size_t sz;
266 ret = btr_node_status(btrn, 0, BTR_NT_LEAF);
267 if (ret < 0)
268 goto out;
269 if (ret == 0)
270 return;
271 if (!FD_ISSET(ct->scc.fd, &s->wfds))
272 return;
273 sz = btr_next_buffer(btrn, &buf2);
274 ret = sc_send_bin_buffer(&ct->scc, buf2, sz);
275 if (ret < 0)
276 goto out;
277 btr_consume(btrn, sz);
278 return;
279 }
280 case CL_RECEIVING:
281 {
282 char *buf2;
283 ret = btr_node_status(btrn, 0, BTR_NT_ROOT);
284 if (ret < 0)
285 goto out;
286 if (ret == 0)
287 return;
288 /*
289 * The FD_ISSET() is not strictly necessary, but is allows us
290 * to skip the malloc below if there is nothing to read anyway.
291 */
292 if (!FD_ISSET(ct->scc.fd, &s->rfds))
293 return;
294 buf2 = para_malloc(CLIENT_BUFSIZE);
295 ret = client_recv_buffer(ct, &s->rfds, buf2, CLIENT_BUFSIZE, &n);
296 if (n > 0) {
297 buf2 = para_realloc(buf2, n);
298 btr_add_output(buf2, n, btrn);
299 } else
300 free(buf2);
301 goto out;
302 }
303 }
304 out:
305 t->error = ret;
306 if (ret < 0) {
307 if (ret != -E_SERVER_EOF && ret != -E_BTR_EOF)
308 PARA_ERROR_LOG("%s\n", para_strerror(-t->error));
309 btr_remove_node(btrn);
310 }
311 }
312
313 /* connect to para_server and register the client task */
314 static int client_connect(struct client_task *ct)
315 {
316 int ret;
317
318 ct->scc.fd = -1;
319 ret = para_connect_simple(IPPROTO_TCP, ct->conf.hostname_arg,
320 ct->conf.server_port_arg);
321 if (ret < 0)
322 return ret;
323 ct->scc.fd = ret;
324 ct->status = CL_CONNECTED;
325 ret = mark_fd_nonblocking(ct->scc.fd);
326 if (ret < 0)
327 goto err_out;
328 ct->task.pre_select = client_pre_select;
329 ct->task.post_select = client_post_select;
330 sprintf(ct->task.status, "client");
331 register_task(&ct->task);
332 return 1;
333 err_out:
334 close(ct->scc.fd);
335 ct->scc.fd = -1;
336 return ret;
337 }
338
339 /**
340 * Open connection to para_server.
341 *
342 * \param argc Usual argument count.
343 * \param argv Usual argument vector.
344 * \param ct_ptr Points to dynamically allocated and initialized client task
345 * struct upon successful return.
346 * \param loglevel If not \p NULL, the number of the loglevel is stored here.
347 * \param parent Add the new buffer tree node as a child of this node.
348 * \param child Add the new buffer tree node as a parent of this node.
349 *
350 * Check the command line options given by \a argc and argv, set default values
351 * for user name and rsa key file, read further option from the config file.
352 * Finally, establish a connection to para_server.
353 *
354 * \return Standard.
355 */
356 int client_open(int argc, char *argv[], struct client_task **ct_ptr,
357 int *loglevel, struct btr_node *parent, struct btr_node *child)
358 {
359 char *home = para_homedir();
360 int ret;
361 struct client_task *ct = para_calloc(sizeof(struct client_task));
362
363 ct->btrn = btr_new_node(&(struct btr_node_description)
364 EMBRACE(.name = "client", .parent = parent, .child = child));
365 *ct_ptr = ct;
366 ct->scc.fd = -1;
367 ret = -E_CLIENT_SYNTAX;
368 if (client_cmdline_parser(argc, argv, &ct->conf))
369 goto out;
370 HANDLE_VERSION_FLAG("client", ct->conf);
371 ret = -E_CLIENT_SYNTAX;
372 if (!ct->conf.inputs_num)
373 goto out;
374
375 ct->config_file = ct->conf.config_file_given?
376 para_strdup(ct->conf.config_file_arg) :
377 make_message("%s/.paraslash/client.conf", home);
378 ret = file_exists(ct->config_file);
379 if (!ret && ct->conf.config_file_given) {
380 ret = -E_NO_CONFIG;
381 goto out;
382 }
383 if (ret) {
384 struct client_cmdline_parser_params params = {
385 .override = 0,
386 .initialize = 0,
387 .check_required = 0,
388 .check_ambiguity = 0,
389 .print_errors = 0
390 };
391 ret = -E_BAD_CONFIG;
392 if (client_cmdline_parser_config_file(ct->config_file,
393 &ct->conf, &params))
394 goto out;
395 }
396 ct->user = ct->conf.user_given?
397 para_strdup(ct->conf.user_arg) : para_logname();
398
399 ct->key_file = ct->conf.key_file_given?
400 para_strdup(ct->conf.key_file_arg) :
401 make_message("%s/.paraslash/key.%s", home, ct->user);
402
403 if (loglevel)
404 *loglevel = get_loglevel_by_name(ct->conf.loglevel_arg);
405 PARA_INFO_LOG("loglevel: %s\n", ct->conf.loglevel_arg);
406 PARA_INFO_LOG("config_file: %s\n", ct->config_file);
407 PARA_INFO_LOG("key_file: %s\n", ct->key_file);
408 PARA_NOTICE_LOG("connecting %s:%d\n", ct->conf.hostname_arg,
409 ct->conf.server_port_arg);
410 ret = client_connect(ct);
411 out:
412 free(home);
413 if (ret < 0) {
414 PARA_ERROR_LOG("%s\n", para_strerror(-ret));
415 btr_remove_node(ct->btrn);
416 btr_free_node(ct->btrn);
417 client_close(ct);
418 *ct_ptr = NULL;
419 }
420 return ret;
421 }