1 /*
2 * Copyright (C) 2011 Intel Corporation. All rights reserved.
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; either version 2 of the License, or
7 * (at your option) any later version.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the
16 * Free Software Foundation, Inc.,
17 * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
18 */
19
20 #define pr_fmt(fmt) "llcp: %s: " fmt, __func__
21
22 #include <linux/init.h>
23 #include <linux/kernel.h>
24 #include <linux/module.h>
25 #include <linux/nfc.h>
26
27 #include <net/nfc/nfc.h>
28
29 #include "../nfc.h"
30 #include "llcp.h"
31
32 static u8 llcp_tlv_length[LLCP_TLV_MAX] = {
33 0,
34 1, /* VERSION */
35 2, /* MIUX */
36 2, /* WKS */
37 1, /* LTO */
38 1, /* RW */
39 0, /* SN */
40 1, /* OPT */
41 0, /* SDREQ */
42 2, /* SDRES */
43
44 };
45
llcp_tlv8(u8 * tlv,u8 type)46 static u8 llcp_tlv8(u8 *tlv, u8 type)
47 {
48 if (tlv[0] != type || tlv[1] != llcp_tlv_length[tlv[0]])
49 return 0;
50
51 return tlv[2];
52 }
53
llcp_tlv16(u8 * tlv,u8 type)54 static u8 llcp_tlv16(u8 *tlv, u8 type)
55 {
56 if (tlv[0] != type || tlv[1] != llcp_tlv_length[tlv[0]])
57 return 0;
58
59 return be16_to_cpu(*((__be16 *)(tlv + 2)));
60 }
61
62
llcp_tlv_version(u8 * tlv)63 static u8 llcp_tlv_version(u8 *tlv)
64 {
65 return llcp_tlv8(tlv, LLCP_TLV_VERSION);
66 }
67
llcp_tlv_miux(u8 * tlv)68 static u16 llcp_tlv_miux(u8 *tlv)
69 {
70 return llcp_tlv16(tlv, LLCP_TLV_MIUX) & 0x7f;
71 }
72
llcp_tlv_wks(u8 * tlv)73 static u16 llcp_tlv_wks(u8 *tlv)
74 {
75 return llcp_tlv16(tlv, LLCP_TLV_WKS);
76 }
77
llcp_tlv_lto(u8 * tlv)78 static u16 llcp_tlv_lto(u8 *tlv)
79 {
80 return llcp_tlv8(tlv, LLCP_TLV_LTO);
81 }
82
llcp_tlv_opt(u8 * tlv)83 static u8 llcp_tlv_opt(u8 *tlv)
84 {
85 return llcp_tlv8(tlv, LLCP_TLV_OPT);
86 }
87
llcp_tlv_rw(u8 * tlv)88 static u8 llcp_tlv_rw(u8 *tlv)
89 {
90 return llcp_tlv8(tlv, LLCP_TLV_RW) & 0xf;
91 }
92
nfc_llcp_build_tlv(u8 type,u8 * value,u8 value_length,u8 * tlv_length)93 u8 *nfc_llcp_build_tlv(u8 type, u8 *value, u8 value_length, u8 *tlv_length)
94 {
95 u8 *tlv, length;
96
97 pr_debug("type %d\n", type);
98
99 if (type >= LLCP_TLV_MAX)
100 return NULL;
101
102 length = llcp_tlv_length[type];
103 if (length == 0 && value_length == 0)
104 return NULL;
105 else
106 length = value_length;
107
108 *tlv_length = 2 + length;
109 tlv = kzalloc(2 + length, GFP_KERNEL);
110 if (tlv == NULL)
111 return tlv;
112
113 tlv[0] = type;
114 tlv[1] = length;
115 memcpy(tlv + 2, value, length);
116
117 return tlv;
118 }
119
nfc_llcp_parse_tlv(struct nfc_llcp_local * local,u8 * tlv_array,u16 tlv_array_len)120 int nfc_llcp_parse_tlv(struct nfc_llcp_local *local,
121 u8 *tlv_array, u16 tlv_array_len)
122 {
123 u8 *tlv = tlv_array, type, length, offset = 0;
124
125 pr_debug("TLV array length %d\n", tlv_array_len);
126
127 if (local == NULL)
128 return -ENODEV;
129
130 while (offset < tlv_array_len) {
131 type = tlv[0];
132 length = tlv[1];
133
134 pr_debug("type 0x%x length %d\n", type, length);
135
136 switch (type) {
137 case LLCP_TLV_VERSION:
138 local->remote_version = llcp_tlv_version(tlv);
139 break;
140 case LLCP_TLV_MIUX:
141 local->remote_miu = llcp_tlv_miux(tlv) + 128;
142 break;
143 case LLCP_TLV_WKS:
144 local->remote_wks = llcp_tlv_wks(tlv);
145 break;
146 case LLCP_TLV_LTO:
147 local->remote_lto = llcp_tlv_lto(tlv) * 10;
148 break;
149 case LLCP_TLV_OPT:
150 local->remote_opt = llcp_tlv_opt(tlv);
151 break;
152 case LLCP_TLV_RW:
153 local->remote_rw = llcp_tlv_rw(tlv);
154 break;
155 default:
156 pr_err("Invalid gt tlv value 0x%x\n", type);
157 break;
158 }
159
160 offset += length + 2;
161 tlv += length + 2;
162 }
163
164 pr_debug("version 0x%x miu %d lto %d opt 0x%x wks 0x%x rw %d\n",
165 local->remote_version, local->remote_miu,
166 local->remote_lto, local->remote_opt,
167 local->remote_wks, local->remote_rw);
168
169 return 0;
170 }
171
llcp_add_header(struct sk_buff * pdu,u8 dsap,u8 ssap,u8 ptype)172 static struct sk_buff *llcp_add_header(struct sk_buff *pdu,
173 u8 dsap, u8 ssap, u8 ptype)
174 {
175 u8 header[2];
176
177 pr_debug("ptype 0x%x dsap 0x%x ssap 0x%x\n", ptype, dsap, ssap);
178
179 header[0] = (u8)((dsap << 2) | (ptype >> 2));
180 header[1] = (u8)((ptype << 6) | ssap);
181
182 pr_debug("header 0x%x 0x%x\n", header[0], header[1]);
183
184 memcpy(skb_put(pdu, LLCP_HEADER_SIZE), header, LLCP_HEADER_SIZE);
185
186 return pdu;
187 }
188
llcp_add_tlv(struct sk_buff * pdu,u8 * tlv,u8 tlv_length)189 static struct sk_buff *llcp_add_tlv(struct sk_buff *pdu, u8 *tlv, u8 tlv_length)
190 {
191 /* XXX Add an skb length check */
192
193 if (tlv == NULL)
194 return NULL;
195
196 memcpy(skb_put(pdu, tlv_length), tlv, tlv_length);
197
198 return pdu;
199 }
200
llcp_allocate_pdu(struct nfc_llcp_sock * sock,u8 cmd,u16 size)201 static struct sk_buff *llcp_allocate_pdu(struct nfc_llcp_sock *sock,
202 u8 cmd, u16 size)
203 {
204 struct sk_buff *skb;
205 int err;
206
207 if (sock->ssap == 0)
208 return NULL;
209
210 skb = nfc_alloc_send_skb(sock->dev, &sock->sk, MSG_DONTWAIT,
211 size + LLCP_HEADER_SIZE, &err);
212 if (skb == NULL) {
213 pr_err("Could not allocate PDU\n");
214 return NULL;
215 }
216
217 skb = llcp_add_header(skb, sock->dsap, sock->ssap, cmd);
218
219 return skb;
220 }
221
nfc_llcp_disconnect(struct nfc_llcp_sock * sock)222 int nfc_llcp_disconnect(struct nfc_llcp_sock *sock)
223 {
224 struct sk_buff *skb;
225 struct nfc_dev *dev;
226 struct nfc_llcp_local *local;
227 u16 size = 0;
228
229 pr_debug("Sending DISC\n");
230
231 local = sock->local;
232 if (local == NULL)
233 return -ENODEV;
234
235 dev = sock->dev;
236 if (dev == NULL)
237 return -ENODEV;
238
239 size += LLCP_HEADER_SIZE;
240 size += dev->tx_headroom + dev->tx_tailroom + NFC_HEADER_SIZE;
241
242 skb = alloc_skb(size, GFP_ATOMIC);
243 if (skb == NULL)
244 return -ENOMEM;
245
246 skb_reserve(skb, dev->tx_headroom + NFC_HEADER_SIZE);
247
248 skb = llcp_add_header(skb, sock->ssap, sock->dsap, LLCP_PDU_DISC);
249
250 skb_queue_tail(&local->tx_queue, skb);
251
252 return 0;
253 }
254
nfc_llcp_send_symm(struct nfc_dev * dev)255 int nfc_llcp_send_symm(struct nfc_dev *dev)
256 {
257 struct sk_buff *skb;
258 struct nfc_llcp_local *local;
259 u16 size = 0;
260
261 pr_debug("Sending SYMM\n");
262
263 local = nfc_llcp_find_local(dev);
264 if (local == NULL)
265 return -ENODEV;
266
267 size += LLCP_HEADER_SIZE;
268 size += dev->tx_headroom + dev->tx_tailroom + NFC_HEADER_SIZE;
269
270 skb = alloc_skb(size, GFP_KERNEL);
271 if (skb == NULL)
272 return -ENOMEM;
273
274 skb_reserve(skb, dev->tx_headroom + NFC_HEADER_SIZE);
275
276 skb = llcp_add_header(skb, 0, 0, LLCP_PDU_SYMM);
277
278 return nfc_data_exchange(dev, local->target_idx, skb,
279 nfc_llcp_recv, local);
280 }
281
nfc_llcp_send_connect(struct nfc_llcp_sock * sock)282 int nfc_llcp_send_connect(struct nfc_llcp_sock *sock)
283 {
284 struct nfc_llcp_local *local;
285 struct sk_buff *skb;
286 u8 *service_name_tlv = NULL, service_name_tlv_length;
287 int err;
288 u16 size = 0;
289
290 pr_debug("Sending CONNECT\n");
291
292 local = sock->local;
293 if (local == NULL)
294 return -ENODEV;
295
296 if (sock->service_name != NULL) {
297 service_name_tlv = nfc_llcp_build_tlv(LLCP_TLV_SN,
298 sock->service_name,
299 sock->service_name_len,
300 &service_name_tlv_length);
301 size += service_name_tlv_length;
302 }
303
304 pr_debug("SKB size %d SN length %zu\n", size, sock->service_name_len);
305
306 skb = llcp_allocate_pdu(sock, LLCP_PDU_CONNECT, size);
307 if (skb == NULL) {
308 err = -ENOMEM;
309 goto error_tlv;
310 }
311
312 if (service_name_tlv != NULL)
313 skb = llcp_add_tlv(skb, service_name_tlv,
314 service_name_tlv_length);
315
316 skb_queue_tail(&local->tx_queue, skb);
317
318 return 0;
319
320 error_tlv:
321 pr_err("error %d\n", err);
322
323 kfree(service_name_tlv);
324
325 return err;
326 }
327
nfc_llcp_send_cc(struct nfc_llcp_sock * sock)328 int nfc_llcp_send_cc(struct nfc_llcp_sock *sock)
329 {
330 struct nfc_llcp_local *local;
331 struct sk_buff *skb;
332
333 pr_debug("Sending CC\n");
334
335 local = sock->local;
336 if (local == NULL)
337 return -ENODEV;
338
339 skb = llcp_allocate_pdu(sock, LLCP_PDU_CC, 0);
340 if (skb == NULL)
341 return -ENOMEM;
342
343 skb_queue_tail(&local->tx_queue, skb);
344
345 return 0;
346 }
347
nfc_llcp_send_dm(struct nfc_llcp_local * local,u8 ssap,u8 dsap,u8 reason)348 int nfc_llcp_send_dm(struct nfc_llcp_local *local, u8 ssap, u8 dsap, u8 reason)
349 {
350 struct sk_buff *skb;
351 struct nfc_dev *dev;
352 u16 size = 1; /* Reason code */
353
354 pr_debug("Sending DM reason 0x%x\n", reason);
355
356 if (local == NULL)
357 return -ENODEV;
358
359 dev = local->dev;
360 if (dev == NULL)
361 return -ENODEV;
362
363 size += LLCP_HEADER_SIZE;
364 size += dev->tx_headroom + dev->tx_tailroom + NFC_HEADER_SIZE;
365
366 skb = alloc_skb(size, GFP_KERNEL);
367 if (skb == NULL)
368 return -ENOMEM;
369
370 skb_reserve(skb, dev->tx_headroom + NFC_HEADER_SIZE);
371
372 skb = llcp_add_header(skb, ssap, dsap, LLCP_PDU_DM);
373
374 memcpy(skb_put(skb, 1), &reason, 1);
375
376 skb_queue_head(&local->tx_queue, skb);
377
378 return 0;
379 }
380
nfc_llcp_send_disconnect(struct nfc_llcp_sock * sock)381 int nfc_llcp_send_disconnect(struct nfc_llcp_sock *sock)
382 {
383 struct sk_buff *skb;
384 struct nfc_llcp_local *local;
385
386 pr_debug("Send DISC\n");
387
388 local = sock->local;
389 if (local == NULL)
390 return -ENODEV;
391
392 skb = llcp_allocate_pdu(sock, LLCP_PDU_DISC, 0);
393 if (skb == NULL)
394 return -ENOMEM;
395
396 skb_queue_head(&local->tx_queue, skb);
397
398 return 0;
399 }
400