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 u16 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) & 0x7ff;
  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 if (length == 0)
 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_gb_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                 default:
 153                         pr_err("Invalid gt tlv value 0x%x\n", type);
 154                         break;
 155                 }
 156
 157                 offset += length + 2;
 158                 tlv += length + 2;
 159         }
 160
 161         pr_debug("version 0x%x miu %d lto %d opt 0x%x wks 0x%x\n",
 162                  local->remote_version, local->remote_miu,
 163                  local->remote_lto, local->remote_opt,
 164                  local->remote_wks);
 165
 166         return 0;
 167 }
 168
 169 int nfc_llcp_parse_connection_tlv(struct nfc_llcp_sock *sock,
 170                                   u8 *tlv_array, u16 tlv_array_len)
 171 {
 172         u8 *tlv = tlv_array, type, length, offset = 0;
 173
 174         pr_debug("TLV array length %d\n", tlv_array_len);
 175
 176         if (sock == NULL)
 177                 return -ENOTCONN;
 178
 179         while (offset < tlv_array_len) {
 180                 type = tlv[0];
 181                 length = tlv[1];
 182
 183                 pr_debug("type 0x%x length %d\n", type, length);
 184
 185                 switch (type) {
 186                 case LLCP_TLV_MIUX:
 187                         sock->miu = llcp_tlv_miux(tlv) + 128;
 188                         break;
 189                 case LLCP_TLV_RW:
 190                         sock->rw = llcp_tlv_rw(tlv);
 191                         break;
 192                 case LLCP_TLV_SN:
 193                         break;
 194                 default:
 195                         pr_err("Invalid gt tlv value 0x%x\n", type);
 196                         break;
 197                 }
 198
 199                 offset += length + 2;
 200                 tlv += length + 2;
 201         }
 202
 203         pr_debug("sock %p rw %d miu %d\n", sock, sock->rw, sock->miu);
 204
 205         return 0;
 206 }
 207
 208 static struct sk_buff *llcp_add_header(struct sk_buff *pdu,
 209                                        u8 dsap, u8 ssap, u8 ptype)
 210 {
 211         u8 header[2];
 212
 213         pr_debug("ptype 0x%x dsap 0x%x ssap 0x%x\n", ptype, dsap, ssap);
 214
 215         header[0] = (u8)((dsap << 2) | (ptype >> 2));
 216         header[1] = (u8)((ptype << 6) | ssap);
 217
 218         pr_debug("header 0x%x 0x%x\n", header[0], header[1]);
 219
 220         memcpy(skb_put(pdu, LLCP_HEADER_SIZE), header, LLCP_HEADER_SIZE);
 221
 222         return pdu;
 223 }
 224
 225 static struct sk_buff *llcp_add_tlv(struct sk_buff *pdu, u8 *tlv,
 226                                     u8 tlv_length)
 227 {
 228         /* XXX Add an skb length check */
 229
 230         if (tlv == NULL)
 231                 return NULL;
 232
 233         memcpy(skb_put(pdu, tlv_length), tlv, tlv_length);
 234
 235         return pdu;
 236 }
 237
 238 static struct sk_buff *llcp_allocate_pdu(struct nfc_llcp_sock *sock,
 239                                          u8 cmd, u16 size)
 240 {
 241         struct sk_buff *skb;
 242         int err;
 243
 244         if (sock->ssap == 0)
 245                 return NULL;
 246
 247         skb = nfc_alloc_send_skb(sock->dev, &sock->sk, MSG_DONTWAIT,
 248                                  size + LLCP_HEADER_SIZE, &err);
 249         if (skb == NULL) {
 250                 pr_err("Could not allocate PDU\n");
 251                 return NULL;
 252         }
 253
 254         skb = llcp_add_header(skb, sock->dsap, sock->ssap, cmd);
 255
 256         return skb;
 257 }
 258
 259 int nfc_llcp_disconnect(struct nfc_llcp_sock *sock)
 260 {
 261         struct sk_buff *skb;
 262         struct nfc_dev *dev;
 263         struct nfc_llcp_local *local;
 264
 265         pr_debug("Sending DISC\n");
 266
 267         local = sock->local;
 268         if (local == NULL)
 269                 return -ENODEV;
 270
 271         dev = sock->dev;
 272         if (dev == NULL)
 273                 return -ENODEV;
 274
 275         skb = llcp_allocate_pdu(sock, LLCP_PDU_DISC, 0);
 276         if (skb == NULL)
 277                 return -ENOMEM;
 278
 279         skb_queue_tail(&local->tx_queue, skb);
 280
 281         return 0;
 282 }
 283
 284 int nfc_llcp_send_symm(struct nfc_dev *dev)
 285 {
 286         struct sk_buff *skb;
 287         struct nfc_llcp_local *local;
 288         u16 size = 0;
 289
 290         pr_debug("Sending SYMM\n");
 291
 292         local = nfc_llcp_find_local(dev);
 293         if (local == NULL)
 294                 return -ENODEV;
 295
 296         size += LLCP_HEADER_SIZE;
 297         size += dev->tx_headroom + dev->tx_tailroom + NFC_HEADER_SIZE;
 298
 299         skb = alloc_skb(size, GFP_KERNEL);
 300         if (skb == NULL)
 301                 return -ENOMEM;
 302
 303         skb_reserve(skb, dev->tx_headroom + NFC_HEADER_SIZE);
 304
 305         skb = llcp_add_header(skb, 0, 0, LLCP_PDU_SYMM);
 306
 307         nfc_llcp_send_to_raw_sock(local, skb, NFC_LLCP_DIRECTION_TX);
 308
 309         return nfc_data_exchange(dev, local->target_idx, skb,
 310                                  nfc_llcp_recv, local);
 311 }
 312
 313 int nfc_llcp_send_connect(struct nfc_llcp_sock *sock)
 314 {
 315         struct nfc_llcp_local *local;
 316         struct sk_buff *skb;
 317         u8 *service_name_tlv = NULL, service_name_tlv_length;
 318         u8 *miux_tlv = NULL, miux_tlv_length;
 319         u8 *rw_tlv = NULL, rw_tlv_length, rw;
 320         __be16 miux;
 321         int err;
 322         u16 size = 0;
 323
 324         pr_debug("Sending CONNECT\n");
 325
 326         local = sock->local;
 327         if (local == NULL)
 328                 return -ENODEV;
 329
 330         if (sock->service_name != NULL) {
 331                 service_name_tlv = nfc_llcp_build_tlv(LLCP_TLV_SN,
 332                                                       sock->service_name,
 333                                                       sock->service_name_len,
 334                                                       &service_name_tlv_length);
 335                 size += service_name_tlv_length;
 336         }
 337
 338         miux = cpu_to_be16(LLCP_MAX_MIUX);
 339         miux_tlv = nfc_llcp_build_tlv(LLCP_TLV_MIUX, (u8 *)&miux, 0,
 340                                       &miux_tlv_length);
 341         size += miux_tlv_length;
 342
 343         rw = LLCP_MAX_RW;
 344         rw_tlv = nfc_llcp_build_tlv(LLCP_TLV_RW, &rw, 0, &rw_tlv_length);
 345         size += rw_tlv_length;
 346
 347         pr_debug("SKB size %d SN length %zu\n", size, sock->service_name_len);
 348
 349         skb = llcp_allocate_pdu(sock, LLCP_PDU_CONNECT, size);
 350         if (skb == NULL) {
 351                 err = -ENOMEM;
 352                 goto error_tlv;
 353         }
 354
 355         if (service_name_tlv != NULL)
 356                 skb = llcp_add_tlv(skb, service_name_tlv,
 357                                    service_name_tlv_length);
 358
 359         skb = llcp_add_tlv(skb, miux_tlv, miux_tlv_length);
 360         skb = llcp_add_tlv(skb, rw_tlv, rw_tlv_length);
 361
 362         skb_queue_tail(&local->tx_queue, skb);
 363
 364         return 0;
 365
 366 error_tlv:
 367         pr_err("error %d\n", err);
 368
 369         kfree(service_name_tlv);
 370         kfree(miux_tlv);
 371         kfree(rw_tlv);
 372
 373         return err;
 374 }
 375
 376 int nfc_llcp_send_cc(struct nfc_llcp_sock *sock)
 377 {
 378         struct nfc_llcp_local *local;
 379         struct sk_buff *skb;
 380         u8 *miux_tlv = NULL, miux_tlv_length;
 381         u8 *rw_tlv = NULL, rw_tlv_length, rw;
 382         __be16 miux;
 383         int err;
 384         u16 size = 0;
 385
 386         pr_debug("Sending CC\n");
 387
 388         local = sock->local;
 389         if (local == NULL)
 390                 return -ENODEV;
 391
 392         miux = cpu_to_be16(LLCP_MAX_MIUX);
 393         miux_tlv = nfc_llcp_build_tlv(LLCP_TLV_MIUX, (u8 *)&miux, 0,
 394                                       &miux_tlv_length);
 395         size += miux_tlv_length;
 396
 397         rw = LLCP_MAX_RW;
 398         rw_tlv = nfc_llcp_build_tlv(LLCP_TLV_RW, &rw, 0, &rw_tlv_length);
 399         size += rw_tlv_length;
 400
 401         skb = llcp_allocate_pdu(sock, LLCP_PDU_CC, size);
 402         if (skb == NULL) {
 403                 err = -ENOMEM;
 404                 goto error_tlv;
 405         }
 406
 407         skb = llcp_add_tlv(skb, miux_tlv, miux_tlv_length);
 408         skb = llcp_add_tlv(skb, rw_tlv, rw_tlv_length);
 409
 410         skb_queue_tail(&local->tx_queue, skb);
 411
 412         return 0;
 413
 414 error_tlv:
 415         pr_err("error %d\n", err);
 416
 417         kfree(miux_tlv);
 418         kfree(rw_tlv);
 419
 420         return err;
 421 }
 422
 423 int nfc_llcp_send_dm(struct nfc_llcp_local *local, u8 ssap, u8 dsap, u8 reason)
 424 {
 425         struct sk_buff *skb;
 426         struct nfc_dev *dev;
 427         u16 size = 1; /* Reason code */
 428
 429         pr_debug("Sending DM reason 0x%x\n", reason);
 430
 431         if (local == NULL)
 432                 return -ENODEV;
 433
 434         dev = local->dev;
 435         if (dev == NULL)
 436                 return -ENODEV;
 437
 438         size += LLCP_HEADER_SIZE;
 439         size += dev->tx_headroom + dev->tx_tailroom + NFC_HEADER_SIZE;
 440
 441         skb = alloc_skb(size, GFP_KERNEL);
 442         if (skb == NULL)
 443                 return -ENOMEM;
 444
 445         skb_reserve(skb, dev->tx_headroom + NFC_HEADER_SIZE);
 446
 447         skb = llcp_add_header(skb, dsap, ssap, LLCP_PDU_DM);
 448
 449         memcpy(skb_put(skb, 1), &reason, 1);
 450
 451         skb_queue_head(&local->tx_queue, skb);
 452
 453         return 0;
 454 }
 455
 456 int nfc_llcp_send_disconnect(struct nfc_llcp_sock *sock)
 457 {
 458         struct sk_buff *skb;
 459         struct nfc_llcp_local *local;
 460
 461         pr_debug("Send DISC\n");
 462
 463         local = sock->local;
 464         if (local == NULL)
 465                 return -ENODEV;
 466
 467         skb = llcp_allocate_pdu(sock, LLCP_PDU_DISC, 0);
 468         if (skb == NULL)
 469                 return -ENOMEM;
 470
 471         skb_queue_head(&local->tx_queue, skb);
 472
 473         return 0;
 474 }
 475
 476 int nfc_llcp_send_i_frame(struct nfc_llcp_sock *sock,
 477                           struct msghdr *msg, size_t len)
 478 {
 479         struct sk_buff *pdu;
 480         struct sock *sk = &sock->sk;
 481         struct nfc_llcp_local *local;
 482         size_t frag_len = 0, remaining_len;
 483         u8 *msg_data, *msg_ptr;
 484
 485         pr_debug("Send I frame len %zd\n", len);
 486
 487         local = sock->local;
 488         if (local == NULL)
 489                 return -ENODEV;
 490
 491         msg_data = kzalloc(len, GFP_KERNEL);
 492         if (msg_data == NULL)
 493                 return -ENOMEM;
 494
 495         if (memcpy_fromiovec(msg_data, msg->msg_iov, len)) {
 496                 kfree(msg_data);
 497                 return -EFAULT;
 498         }
 499
 500         remaining_len = len;
 501         msg_ptr = msg_data;
 502
 503         while (remaining_len > 0) {
 504
 505                 frag_len = min_t(size_t, sock->miu, remaining_len);
 506
 507                 pr_debug("Fragment %zd bytes remaining %zd",
 508                          frag_len, remaining_len);
 509
 510                 pdu = llcp_allocate_pdu(sock, LLCP_PDU_I,
 511                                         frag_len + LLCP_SEQUENCE_SIZE);
 512                 if (pdu == NULL)
 513                         return -ENOMEM;
 514
 515                 skb_put(pdu, LLCP_SEQUENCE_SIZE);
 516
 517                 memcpy(skb_put(pdu, frag_len), msg_ptr, frag_len);
 518
 519                 skb_queue_tail(&sock->tx_queue, pdu);
 520
 521                 lock_sock(sk);
 522
 523                 nfc_llcp_queue_i_frames(sock);
 524
 525                 release_sock(sk);
 526
 527                 remaining_len -= frag_len;
 528                 msg_ptr += frag_len;
 529         }
 530
 531         kfree(msg_data);
 532
 533         return len;
 534 }
 535
 536 int nfc_llcp_send_rr(struct nfc_llcp_sock *sock)
 537 {
 538         struct sk_buff *skb;
 539         struct nfc_llcp_local *local;
 540
 541         pr_debug("Send rr nr %d\n", sock->recv_n);
 542
 543         local = sock->local;
 544         if (local == NULL)
 545                 return -ENODEV;
 546
 547         skb = llcp_allocate_pdu(sock, LLCP_PDU_RR, LLCP_SEQUENCE_SIZE);
 548         if (skb == NULL)
 549                 return -ENOMEM;
 550
 551         skb_put(skb, LLCP_SEQUENCE_SIZE);
 552
 553         skb->data[2] = sock->recv_n;
 554
 555         skb_queue_head(&local->tx_queue, skb);
 556
 557         return 0;
 558 }