net/nfc/llcp/commands.c

   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
  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
  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
  63 static u8 llcp_tlv_version(u8 *tlv)
  64 {
  65         return llcp_tlv8(tlv, LLCP_TLV_VERSION);
  66 }
  67
  68 static u16 llcp_tlv_miux(u8 *tlv)
  69 {
  70         return llcp_tlv16(tlv, LLCP_TLV_MIUX) & 0x7f;
  71 }
  72
  73 static u16 llcp_tlv_wks(u8 *tlv)
  74 {
  75         return llcp_tlv16(tlv, LLCP_TLV_WKS);
  76 }
  77
  78 static u16 llcp_tlv_lto(u8 *tlv)
  79 {
  80         return llcp_tlv8(tlv, LLCP_TLV_LTO);
  81 }
  82
  83 static u8 llcp_tlv_opt(u8 *tlv)
  84 {
  85         return llcp_tlv8(tlv, LLCP_TLV_OPT);
  86 }
  87
  88 static u8 llcp_tlv_rw(u8 *tlv)
  89 {
  90         return llcp_tlv8(tlv, LLCP_TLV_RW) & 0xf;
  91 }
  92
  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
 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
 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
 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
 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
 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
 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
 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
 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
 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
 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 }