summaryrefslogtreecommitdiffstats
path: root/src/usbmux.c
blob: 7d74b4bb3de80361c818067bc5068c40c0dffffb (plain)
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
/*
 * usbmux.c
 * Interprets the usb multiplexing protocol used by the iPhone.
 *
 * Copyright (c) 2008 Zach C. All Rights Reserved.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 * 
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA 
 */

#include <sys/types.h>
#include <arpa/inet.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "usbmux.h"
#include "utils.h"

static iphone_umux_client_t *connlist = NULL;
static int clients = 0;

/** Creates a USBMux packet for the given set of ports.
 * 
 * @param s_port The source port for the connection.
 * @param d_port The destination port for the connection.
 *
 * @return A USBMux packet
 */
usbmux_tcp_header *new_mux_packet(uint16_t s_port, uint16_t d_port)
{
	usbmux_tcp_header *conn = (usbmux_tcp_header *) malloc(sizeof(usbmux_tcp_header));
	conn->type = htonl(6);
	conn->length = 28;
	conn->sport = htons(s_port);
	conn->dport = htons(d_port);
	conn->scnt = 0;
	conn->ocnt = 0;
	conn->offset = 0x50;
	conn->window = htons(0x0200);
	conn->nullnull = 0x0000;
	conn->length16 = 28;
	return conn;
}

/** Creates a USBMux header containing version information
 * 
 * @return A USBMux header
 */
usbmux_version_header *version_header(void)
{
	usbmux_version_header *version = (usbmux_version_header *) malloc(sizeof(usbmux_version_header));
	version->type = 0;
	version->length = htonl(20);
	version->major = htonl(1);
	version->minor = 0;
	version->allnull = 0;
	return version;
}


// Maintenance functions.

/** Removes a connection from the list of connections made.
 * The list of connections is necessary for buffering.
 * 
 * @param connection The connection to delete from the tracking list.
 */
static void delete_connection(iphone_umux_client_t connection)
{
	iphone_umux_client_t *newlist = (iphone_umux_client_t *) malloc(sizeof(iphone_umux_client_t) * (clients - 1));
	int i = 0, j = 0;
	for (i = 0; i < clients; i++) {
		if (connlist[i] == connection)
			continue;
		else {
			newlist[j] = connlist[i];
			j++;
		}
	}
	free(connlist);
	connlist = newlist;
	clients--;
	if (connection->recv_buffer)
		free(connection->recv_buffer);
	if (connection->header)
		free(connection->header);
	connection->r_len = 0;
	free(connection);
}

/** Adds a connection to the list of connections made.
 * The connection list is necessary for buffering.
 *
 * @param connection The connection to add to the global list of connections.
 */

static void add_connection(iphone_umux_client_t connection)
{
	iphone_umux_client_t *newlist =
		(iphone_umux_client_t *) realloc(connlist, sizeof(iphone_umux_client_t) * (clients + 1));
	newlist[clients] = connection;
	connlist = newlist;
	clients++;
}

/** Initializes a connection on phone, with source port s_port and destination port d_port
 *
 * @param device The iPhone to initialize a connection on.
 * @param src_port The source port
 * @param dst_port The destination port -- 0xf27e for lockdownd. 
 * @param client A mux TCP header for the connection which is used for tracking and data transfer.
 * @return IPHONE_E_SUCCESS on success, an error code otherwise.
 */
iphone_error_t iphone_mux_new_client(iphone_device_t device, uint16_t src_port, uint16_t dst_port,
									 iphone_umux_client_t * client)
{
	if (!device || !src_port || !dst_port)
		return IPHONE_E_INVALID_ARG;

	int bytes = 0;
	// Initialize connection stuff
	iphone_umux_client_t new_connection = (iphone_umux_client_t) malloc(sizeof(struct iphone_umux_client_int));
	new_connection->header = new_mux_packet(src_port, dst_port);

	// blargg
	if (new_connection && new_connection->header) {
		new_connection->header->tcp_flags = 0x02;
		new_connection->header->length = htonl(new_connection->header->length);
		new_connection->header->length16 = htons(new_connection->header->length16);

		if (send_to_phone(device, (char *) new_connection->header, sizeof(usbmux_tcp_header)) >= 0) {
			usbmux_tcp_header *response;
			response = (usbmux_tcp_header *) malloc(sizeof(usbmux_tcp_header));
			bytes = recv_from_phone(device, (char *) response, sizeof(*response), 3500);
			if (response->tcp_flags != 0x12) {
				free(response);
				return IPHONE_E_UNKNOWN_ERROR;
			} else {
				free(response);

				log_debug_msg("mux_connect: connection success\n");
				new_connection->header->tcp_flags = 0x10;
				new_connection->header->scnt = 1;
				new_connection->header->ocnt = 1;
				new_connection->phone = device;
				new_connection->recv_buffer = NULL;
				new_connection->r_len = 0;
				add_connection(new_connection);
				*client = new_connection;
				return IPHONE_E_SUCCESS;
			}
		} else {
			return IPHONE_E_NOT_ENOUGH_DATA;
		}
	}
	// if we get to this point it's probably bad
	return IPHONE_E_UNKNOWN_ERROR;
}

/** Cleans up the given USBMux connection.
 * @note Once a connection is closed it may not be used again.
 * 
 * @param connection The connection to close.
 *
 * @return IPHONE_E_SUCCESS on success.
 */
iphone_error_t iphone_mux_free_client(iphone_umux_client_t client)
{
	if (!client || !client->phone)
		return IPHONE_E_INVALID_ARG;

	client->header->tcp_flags = 0x04;
	client->header->length = htonl(0x1C);
	client->header->scnt = htonl(client->header->scnt);
	client->header->ocnt = htonl(client->header->ocnt);
	client->header->window = 0;
	client->header->length16 = htons(0x1C);
	int bytes = 0;

	bytes = usb_bulk_write(client->phone->device, BULKOUT, (char *) client->header, sizeof(usbmux_tcp_header), 800);
	if (bytes < 0)
		log_debug_msg("iphone_muxèfree_client(): when writing, libusb gave me the error: %s\n", usb_strerror());

	bytes = usb_bulk_read(client->phone->device, BULKIN, (char *) client->header, sizeof(usbmux_tcp_header), 800);
	if (bytes < 0)
		log_debug_msg("get_iPhone(): when reading, libusb gave me the error: %s\n", usb_strerror());

	delete_connection(client);

	return IPHONE_E_SUCCESS;
}


/** Sends the given data over the selected connection.
 *
 * @param phone The iPhone to send to.
 * @param client The client we're sending data on.
 * @param data A pointer to the data to send.
 * @param datalen How much data we're sending.
 * @param sent_bytes The number of bytes sent, minus the header (28)
 *
 * @return IPHONE_E_SUCCESS on success.
 */

iphone_error_t iphone_mux_send(iphone_umux_client_t client, const char *data, uint32_t datalen, uint32_t * sent_bytes)
{
	if (!client->phone || !client || !data || datalen == 0 || !sent_bytes)
		return IPHONE_E_INVALID_ARG;
	// client->scnt and client->ocnt should already be in host notation...
	// we don't need to change them juuuust yet. 
	*sent_bytes = 0;
	log_debug_msg("mux_send(): client wants to send %i bytes\n", datalen);
	char *buffer = (char *) malloc(sizeof(usbmux_tcp_header) + datalen + 2);	// allow 2 bytes of safety padding
	// Set the length and pre-emptively htonl/htons it
	client->header->length = htonl(sizeof(usbmux_tcp_header) + datalen);
	client->header->length16 = htons(sizeof(usbmux_tcp_header) + datalen);

	// Put scnt and ocnt into big-endian notation
	client->header->scnt = htonl(client->header->scnt);
	client->header->ocnt = htonl(client->header->ocnt);
	// Concatenation of stuff in the buffer.
	memcpy(buffer, client->header, sizeof(usbmux_tcp_header));
	memcpy(buffer + sizeof(usbmux_tcp_header), data, datalen);

	// We have a buffer full of data, we should now send it to the phone.
	log_debug_msg("actually sending %zi bytes of data at %p\n", sizeof(usbmux_tcp_header) + datalen, buffer);


	*sent_bytes = send_to_phone(client->phone, buffer, sizeof(usbmux_tcp_header) + datalen);
	log_debug_msg("mux_send: sent %i bytes!\n", *sent_bytes);
	// Now that we've sent it off, we can clean up after our sloppy selves.
	dump_debug_buffer("packet", buffer, *sent_bytes);
	if (buffer)
		free(buffer);
	// Re-calculate scnt and ocnt
	client->header->scnt = ntohl(client->header->scnt) + datalen;
	client->header->ocnt = ntohl(client->header->ocnt);

	// Revert lengths
	client->header->length = ntohl(client->header->length);
	client->header->length16 = ntohs(client->header->length16);

	// Now return the bytes.
	if (*sent_bytes < sizeof(usbmux_tcp_header) + datalen) {
		*sent_bytes = 0;
		return IPHONE_E_NOT_ENOUGH_DATA;
	} else {
		*sent_bytes = *sent_bytes - 28;	// actual length sent. :/
	}

	return IPHONE_E_SUCCESS;
}

/** This is a higher-level USBMuxTCP-like function
 *
 * @param connection The connection to receive data on.
 * @param data Where to put the data we receive. 
 * @param datalen How much data to read.
 * @param recv_bytes Pointer to a uint32_t that will be set
 *        to the number of bytes received.
 * @param timeout How many milliseconds to wait for data.
 *
 * @return IPHONE_E_SUCCESS on success, or and error value.
 */
iphone_error_t iphone_mux_recv_timeout(iphone_umux_client_t client, char *data, uint32_t datalen, uint32_t * recv_bytes, int timeout)
{

	if (!client || !data || datalen == 0 || !recv_bytes)
		return IPHONE_E_INVALID_ARG;
	/*
	 * Order of operation:
	 * 1.) Check if the client has a pre-received buffer.
	 * 2.) If so, fill data with the buffer, as much as needed.
	 *      a.) Return quickly if the buffer has enough
	 *      b.) If the buffer is only part of the datalen, get the rest of datalen (and if we can't, just return)
	 * 3.) If not, receive directly from the phone. 
	 *      a.) Check incoming packet's ports. If proper, follow proper buffering and receiving operation.
	 *      b.) If not, find the client the ports belong to and fill that client's buffer, then return mux_recv with the same args to try again.
	 */
	log_debug_msg("mux_recv: datalen == %i\n", datalen);
	int bytes = 0, i = 0, complex = 0, offset = 0;
	*recv_bytes = 0;
	char *buffer = NULL;
	usbmux_tcp_header *header = NULL;

	if (client->recv_buffer) {
		if (client->r_len >= datalen) {
			memcpy(data, client->recv_buffer, datalen);
			if (client->r_len == datalen) {
				// reset everything
				free(client->recv_buffer);
				client->r_len = 0;
				client->recv_buffer = NULL;
			} else {
				buffer = (char *) malloc(sizeof(char) * (client->r_len - datalen));
				memcpy(buffer, client->recv_buffer + datalen, (client->r_len - datalen));
				client->r_len -= datalen;
				free(client->recv_buffer);
				client->recv_buffer = buffer;
			}

			// Since we were able to fill the data straight from our buffer, we can just return datalen. See 2a above.
			*recv_bytes = datalen;
			return IPHONE_E_SUCCESS;
		} else {
			memcpy(data, client->recv_buffer, client->r_len);
			free(client->recv_buffer);	// don't need to deal with anymore, but...
			client->recv_buffer = NULL;
			offset = client->r_len;	// see #2b, above
			client->r_len = 0;
		}
	}							// End of what to do if we have a pre-buffer. See #1 and #2 above. 

	buffer = (char *) malloc(sizeof(char) * 131072);	// make sure we get enough ;)

	// See #3.
	bytes = recv_from_phone(client->phone, buffer, 131072, timeout);
	if (bytes < 28) {
		free(buffer);
		log_debug_msg("mux_recv: Did not even get the header.\n");
		return IPHONE_E_NOT_ENOUGH_DATA;
	}

	header = (usbmux_tcp_header *) buffer;
	if (header->sport != client->header->dport || header->dport != client->header->sport) {
		// Ooooops -- we got someone else's packet.
		// We gotta stick it in their buffer. (Take that any old way you want ;) )
		for (i = 0; i < clients; i++) {
			if (connlist[i]->header->sport == header->dport && connlist[i]->header->dport == header->sport) {
				// we have a winner.
				char *nfb = (char *) malloc(sizeof(char) * (connlist[i]->r_len + (bytes - 28)));
				if (connlist[i]->recv_buffer && connlist[i]->r_len) {
					memcpy(nfb, connlist[i]->recv_buffer, connlist[i]->r_len);
					free(connlist[i]->recv_buffer);
				}
				connlist[i]->r_len += bytes - 28;
				//connlist[i]->recv_buffer = (char*)realloc(connlist[i]->recv_buffer, sizeof(char) * client->r_len); // grow their buffer
				connlist[i]->recv_buffer = nfb;
				nfb = NULL;		// A cookie for you if you can guess what "nfb" means. 
				complex = connlist[i]->r_len - (bytes - 28);
				memcpy(connlist[i]->recv_buffer + complex, buffer + 28, bytes - 28);	// paste into their buffer
				connlist[i]->header->ocnt += bytes - 28;
			}
		}
		// If it wasn't ours, it's been handled by this point... or forgotten.
		// Free our buffer and continue.
		free(buffer);
		buffer = NULL;
		return iphone_mux_recv(client, data, datalen, recv_bytes);	// recurse back in to try again
	}
	// The packet was absolutely meant for us if it hits this point.
	// The pre-buffer has been taken care of, so, again, if we're at this point we have to read from the phone.

	if ((bytes - 28) > datalen) {
		// Copy what we need into the data, buffer the rest because we can.
		memcpy(data + offset, buffer + 28, datalen);	// data+offset: see #2b, above
		complex = client->r_len + ((bytes - 28) - datalen);
		client->recv_buffer = (char *) realloc(client->recv_buffer, (sizeof(char) * complex));
		client->r_len = complex;
		complex = client->r_len - ((bytes - 28) - datalen);
		memcpy(client->recv_buffer + complex, buffer + 28 + datalen, (bytes - 28) - datalen);
		free(buffer);
		client->header->ocnt += bytes - 28;
		*recv_bytes = datalen;
		return IPHONE_E_SUCCESS;
	} else {
		// Fill the data with what we have, and just return.
		memcpy(data + offset, buffer + 28, bytes - 28);	// data+offset: see #2b, above
		client->header->ocnt += bytes - 28;
		free(buffer);
		*recv_bytes = bytes - 28;
		return IPHONE_E_SUCCESS;
	}

	// If we get to this point, 'tis probably bad.
	log_debug_msg("mux_recv: Heisenbug: bytes and datalen not matching up\n");
	return IPHONE_E_UNKNOWN_ERROR;
}

/**
 * This function is just like 'iphone_mux_recv_timeout' but you do not need
 * to specify a timeout. It simply calls iphone_mux_recv_timeout with a
 * timeout value of 3500 milliseconds.
 *
 * @param connection The connection to receive data on.
 * @param data Where to put the data we receive.
 * @param datalen How much data to read.
 * @param recv_bytes Pointer to a uint32_t that will be set
 *        to the number of bytes received.
 *
 * @return The return value of iphone_mux_recv_timeout.
 *
 * @see iphone_mux_recv_timeout
 */
iphone_error_t iphone_mux_recv(iphone_umux_client_t client, char *data, uint32_t datalen, uint32_t * recv_bytes)
{
	return iphone_mux_recv_timeout(client, data, datalen, recv_bytes, 3500);
}