Boot Linux faster!

Check our new training course

Boot Linux faster!

Check our new training course
and Creative Commons CC-BY-SA
lecture and lab materials

Bootlin logo

Elixir Cross Referencer

  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
/*
 * Copyright (c) 2017 Intel Corporation
 * Copyright (c) 2019 Nordic Semiconductor ASA
 *
 * SPDX-License-Identifier: Apache-2.0
 */

#include <init.h>

#include <logging/log.h>
#include <net/net_context.h>
#include <net/net_ip.h>
#include <net/net_pkt.h>
#include <shell/shell_telnet.h>

#include "shell_telnet_protocol.h"

SHELL_TELNET_DEFINE(shell_transport_telnet);
SHELL_DEFINE(shell_telnet, CONFIG_SHELL_PROMPT_TELNET, &shell_transport_telnet,
	     CONFIG_SHELL_TELNET_LOG_MESSAGE_QUEUE_SIZE,
	     CONFIG_SHELL_TELNET_LOG_MESSAGE_QUEUE_TIMEOUT,
	     SHELL_FLAG_OLF_CRLF);

LOG_MODULE_REGISTER(shell_telnet, CONFIG_SHELL_TELNET_LOG_LEVEL);

struct shell_telnet *sh_telnet;

/* Various definitions mapping the TELNET service configuration options */
#define TELNET_PORT      CONFIG_SHELL_TELNET_PORT
#define TELNET_LINE_SIZE CONFIG_SHELL_TELNET_LINE_BUF_SIZE
#define TELNET_TIMEOUT   CONFIG_SHELL_TELNET_SEND_TIMEOUT

#define TELNET_MIN_MSG 2

/* Basic TELNET implmentation. */

static void telnet_end_client_connection(void)
{
	struct net_pkt *pkt;

	(void)net_context_put(sh_telnet->client_ctx);

	sh_telnet->client_ctx = NULL;
	sh_telnet->output_lock = false;

	k_delayed_work_cancel(&sh_telnet->send_work);

	/* Flush the RX FIFO */
	while ((pkt = k_fifo_get(&sh_telnet->rx_fifo, K_NO_WAIT)) != NULL) {
		net_pkt_unref(pkt);
	}
}

static void telnet_sent_cb(struct net_context *client,
			   int status, void *user_data)
{
	if (status < 0) {
		telnet_end_client_connection();
		LOG_ERR("Could not send packet %d", status);
	}
}

static void telnet_command_send_reply(u8_t *msg, u16_t len)
{
	int err;

	if (sh_telnet->client_ctx == NULL) {
		return;
	}

	err = net_context_send(sh_telnet->client_ctx, msg, len, telnet_sent_cb,
			       K_FOREVER, NULL);
	if (err < 0) {
		LOG_ERR("Failed to send command %d, shutting down", err);
		telnet_end_client_connection();
	}
}

static void telnet_reply_ay_command(void)
{
	static const char alive[] = "Zephyr at your service\r\n";

	telnet_command_send_reply((u8_t *)alive, strlen(alive));
}

static void telnet_reply_do_command(struct telnet_simple_command *cmd)
{
	switch (cmd->opt) {
	case NVT_OPT_SUPR_GA:
		cmd->op = NVT_CMD_WILL;
		break;
	default:
		cmd->op = NVT_CMD_WONT;
		break;
	}

	telnet_command_send_reply((u8_t *)cmd,
				  sizeof(struct telnet_simple_command));
}

static void telnet_reply_command(struct telnet_simple_command *cmd)
{
	if (!cmd->iac) {
		return;
	}

	switch (cmd->op) {
	case NVT_CMD_AO:
		/* OK, no output then */
		sh_telnet->output_lock = true;
		sh_telnet->line_out.len = 0;
		k_delayed_work_cancel(&sh_telnet->send_work);
		break;
	case NVT_CMD_AYT:
		telnet_reply_ay_command();
		break;
	case NVT_CMD_DO:
		telnet_reply_do_command(cmd);
		break;
	default:
		LOG_DBG("Operation %u not handled", cmd->op);
		break;
	}
}

static int telnet_send(void)
{
	int err;

	if (sh_telnet->line_out.len == 0) {
		return 0;
	}

	if (sh_telnet->client_ctx == NULL) {
		return -ENOTCONN;
	}

	err = net_context_send(sh_telnet->client_ctx, sh_telnet->line_out.buf,
			       sh_telnet->line_out.len, telnet_sent_cb,
			       K_FOREVER, NULL);
	if (err < 0) {
		LOG_ERR("Failed to send %d, shutting down", err);
		telnet_end_client_connection();
		return err;
	}

	/* We reinitialize the line buffer */
	sh_telnet->line_out.len = 0;

	return 0;
}

static void telnet_send_prematurely(struct k_work *work)
{
	(void)telnet_send();
}

static inline bool telnet_handle_command(struct net_pkt *pkt)
{
	/* Commands are two or three bytes. */
	NET_PKT_DATA_ACCESS_CONTIGUOUS_DEFINE(cmd_access, u16_t);
	struct telnet_simple_command *cmd;

	cmd = (struct telnet_simple_command *)net_pkt_get_data(pkt,
							       &cmd_access);
	if (!cmd || cmd->iac != NVT_CMD_IAC) {
		return false;
	}

	if (IS_ENABLED(CONFIG_SHELL_TELNET_SUPPORT_COMMAND)) {
		LOG_DBG("Got a command %u/%u/%u", cmd->iac, cmd->op, cmd->opt);
		telnet_reply_command(cmd);
	}

	return true;
}

static void telnet_recv(struct net_context *client,
			struct net_pkt *pkt,
			union net_ip_header *ip_hdr,
			union net_proto_header *proto_hdr,
			int status,
			void *user_data)
{
	size_t len;

	if (!pkt || status) {
		telnet_end_client_connection();

		LOG_DBG("Telnet client dropped (AF_INET%s) status %d",
			net_context_get_family(client) == AF_INET ?
			"" : "6", status);
		return;
	}

	len = net_pkt_remaining_data(pkt);
	if (len < TELNET_MIN_MSG) {
		LOG_DBG("Packet smaller than minimum length");
		goto unref;
	}

	if (telnet_handle_command(pkt)) {
		LOG_DBG("Handled command");
		goto unref;
	}

	/* Fifo add */
	k_fifo_put(&sh_telnet->rx_fifo, pkt);

	sh_telnet->shell_handler(SHELL_TRANSPORT_EVT_RX_RDY,
				 sh_telnet->shell_context);

	return;

unref:
	net_pkt_unref(pkt);
}

static void telnet_accept(struct net_context *client,
			  struct sockaddr *addr,
			  socklen_t addrlen,
			  int error,
			  void *user_data)
{
	if (error) {
		LOG_ERR("Error %d", error);
		goto error;
	}

	if (sh_telnet->client_ctx) {
		LOG_INF("A telnet client is already in.");
		goto error;
	}

	if (net_context_recv(client, telnet_recv, K_NO_WAIT, NULL)) {
		LOG_ERR("Unable to setup reception (family %u)",
			net_context_get_family(client));
		goto error;
	}

	net_context_set_accepting(client, false);

	LOG_DBG("Telnet client connected (family AF_INET%s)",
		net_context_get_family(client) == AF_INET ? "" : "6");

	sh_telnet->client_ctx = client;

	return;
error:
	net_context_put(client);
}

static void telnet_setup_server(struct net_context **ctx, sa_family_t family,
				struct sockaddr *addr, socklen_t addrlen)
{
	if (net_context_get(family, SOCK_STREAM, IPPROTO_TCP, ctx)) {
		LOG_ERR("No context available");
		goto error;
	}

	if (net_context_bind(*ctx, addr, addrlen)) {
		LOG_ERR("Cannot bind on family AF_INET%s",
			family == AF_INET ? "" : "6");
		goto error;
	}

	if (net_context_listen(*ctx, 0)) {
		LOG_ERR("Cannot listen on");
		goto error;
	}

	if (net_context_accept(*ctx, telnet_accept, K_NO_WAIT, NULL)) {
		LOG_ERR("Cannot accept");
		goto error;
	}

	LOG_DBG("Telnet console enabled on AF_INET%s",
		family == AF_INET ? "" : "6");

	return;
error:
	LOG_ERR("Unable to start telnet on AF_INET%s",
		family == AF_INET ? "" : "6");

	if (*ctx) {
		(void)net_context_put(*ctx);
		*ctx = NULL;
	}
}

static int telnet_init(void)
{
	if (IS_ENABLED(CONFIG_NET_IPV4)) {
		struct sockaddr_in any_addr4 = {
			.sin_family = AF_INET,
			.sin_port = htons(TELNET_PORT),
			.sin_addr = INADDR_ANY_INIT
		};
		static struct net_context *ctx4;

		telnet_setup_server(&ctx4, AF_INET,
				    (struct sockaddr *)&any_addr4,
				    sizeof(any_addr4));
	}

	if (IS_ENABLED(CONFIG_NET_IPV6)) {
		struct sockaddr_in6 any_addr6 = {
			.sin6_family = AF_INET6,
			.sin6_port = htons(TELNET_PORT),
			.sin6_addr = IN6ADDR_ANY_INIT
		};
		static struct net_context *ctx6;

		telnet_setup_server(&ctx6, AF_INET6,
				    (struct sockaddr *)&any_addr6,
				    sizeof(any_addr6));
	}

	LOG_INF("Telnet shell backend initialized");

	return 0;
}

/* Shell API */

static int init(const struct shell_transport *transport,
		const void *config,
		shell_transport_handler_t evt_handler,
		void *context)
{
	int err;

	sh_telnet = (struct shell_telnet *)transport->ctx;

	err = telnet_init();
	if (err != 0) {
		return err;
	}

	memset(sh_telnet, 0, sizeof(struct shell_telnet));

	sh_telnet->shell_handler = evt_handler;
	sh_telnet->shell_context = context;

	k_fifo_init(&sh_telnet->rx_fifo);
	k_delayed_work_init(&sh_telnet->send_work, telnet_send_prematurely);

	return 0;
}

static int uninit(const struct shell_transport *transport)
{
	if (sh_telnet == NULL) {
		return -ENODEV;
	}

	return 0;
}

static int enable(const struct shell_transport *transport, bool blocking)
{
	if (sh_telnet == NULL) {
		return -ENODEV;
	}

	return 0;
}

static int write(const struct shell_transport *transport,
		 const void *data, size_t length, size_t *cnt)
{
	struct shell_telnet_line_buf *lb;
	size_t copy_len;
	int err;
	u32_t timeout;

	if (sh_telnet == NULL) {
		*cnt = 0;
		return -ENODEV;
	}

	if (sh_telnet->client_ctx == NULL || sh_telnet->output_lock) {
		*cnt = length;
		return 0;
	}

	*cnt = 0;
	lb = &sh_telnet->line_out;

	/* Stop the transmission timer, so it does not interrupt the operation.
	 */
	timeout = k_delayed_work_remaining_get(&sh_telnet->send_work);
	k_delayed_work_cancel(&sh_telnet->send_work);

	do {
		if (lb->len + length - *cnt > TELNET_LINE_SIZE) {
			copy_len = TELNET_LINE_SIZE - lb->len;
		} else {
			copy_len = length - *cnt;
		}

		memcpy(lb->buf + lb->len, (u8_t *)data + *cnt, copy_len);
		lb->len += copy_len;

		/* Send the data immediately if the buffer is full or line feed
		 * is recognized.
		 */
		if (lb->buf[lb->len - 1] == '\n' ||
		    lb->len == TELNET_LINE_SIZE) {
			err = telnet_send();
			if (err != 0) {
				*cnt = length;
				return err;
			}
		}

		*cnt += copy_len;
	} while (*cnt < length);

	if (lb->len > 0) {
		/* Check if the timer was already running, initialize otherwise.
		 */
		timeout = (timeout == 0) ? TELNET_TIMEOUT : timeout;

		k_delayed_work_submit(&sh_telnet->send_work, K_MSEC(timeout));
	}

	sh_telnet->shell_handler(SHELL_TRANSPORT_EVT_TX_RDY,
				 sh_telnet->shell_context);

	return 0;
}

static int read(const struct shell_transport *transport,
		void *data, size_t length, size_t *cnt)
{
	struct net_pkt *pkt;
	size_t read_len;
	bool flush = true;

	if (sh_telnet == NULL) {
		return -ENODEV;
	}

	if (sh_telnet->client_ctx == NULL) {
		goto no_data;
	}

	pkt = k_fifo_peek_head(&sh_telnet->rx_fifo);
	if (pkt == NULL) {
		goto no_data;
	}

	read_len = net_pkt_remaining_data(pkt);
	if (read_len > length) {
		read_len = length;
		flush = false;
	}

	*cnt = read_len;
	if (net_pkt_read(pkt, data, read_len) < 0) {
		/* Failed to read, get rid of the faulty packet. */
		LOG_ERR("Failed to read net packet.");
		*cnt = 0;
		flush = true;
	}

	if (flush) {
		(void)k_fifo_get(&sh_telnet->rx_fifo, K_NO_WAIT);
		net_pkt_unref(pkt);
	}

	return 0;

no_data:
	*cnt = 0;
	return 0;
}

const struct shell_transport_api shell_telnet_transport_api = {
	.init = init,
	.uninit = uninit,
	.enable = enable,
	.write = write,
	.read = read
};

static int enable_shell_telnet(struct device *arg)
{
	ARG_UNUSED(arg);

	bool log_backend = CONFIG_SHELL_TELNET_INIT_LOG_LEVEL > 0;
	u32_t level = (CONFIG_SHELL_TELNET_INIT_LOG_LEVEL > LOG_LEVEL_DBG) ?
		      CONFIG_LOG_MAX_LEVEL : CONFIG_SHELL_TELNET_INIT_LOG_LEVEL;

	return shell_init(&shell_telnet, NULL, true, log_backend, level);
}

SYS_INIT(enable_shell_telnet, APPLICATION, 0);

const struct shell *shell_backend_telnet_get_ptr(void)
{
	return &shell_telnet;
}