net/nfc/netlink.c

   1 /*
   2  * Copyright (C) 2011 Instituto Nokia de Tecnologia
   3  *
   4  * Authors:
   5  *    Lauro Ramos Venancio <lauro.venancio@openbossa.org>
   6  *    Aloisio Almeida Jr <aloisio.almeida@openbossa.org>
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License as published by
  10  * the Free Software Foundation; either version 2 of the License, or
  11  * (at your option) any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with this program; if not, write to the
  20  * Free Software Foundation, Inc.,
  21  * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  22  */
  23
  24 #include <net/genetlink.h>
  25 #include <linux/nfc.h>
  26 #include <linux/slab.h>
  27
  28 #include "nfc.h"
  29
  30 static struct genl_multicast_group nfc_genl_event_mcgrp = {
  31         .name = NFC_GENL_MCAST_EVENT_NAME,
  32 };
  33
  34 struct genl_family nfc_genl_family = {
  35         .id = GENL_ID_GENERATE,
  36         .hdrsize = 0,
  37         .name = NFC_GENL_NAME,
  38         .version = NFC_GENL_VERSION,
  39         .maxattr = NFC_ATTR_MAX,
  40 };
  41
  42 static const struct nla_policy nfc_genl_policy[NFC_ATTR_MAX + 1] = {
  43         [NFC_ATTR_DEVICE_INDEX] = { .type = NLA_U32 },
  44         [NFC_ATTR_DEVICE_NAME] = { .type = NLA_STRING,
  45                                 .len = NFC_DEVICE_NAME_MAXSIZE },
  46         [NFC_ATTR_PROTOCOLS] = { .type = NLA_U32 },
  47 };
  48
  49 static int nfc_genl_send_target(struct sk_buff *msg, struct nfc_target *target,
  50                                         struct netlink_callback *cb, int flags)
  51 {
  52         void *hdr;
  53
  54         nfc_dbg("entry");
  55
  56         hdr = genlmsg_put(msg, NETLINK_CB(cb->skb).pid, cb->nlh->nlmsg_seq,
  57                                 &nfc_genl_family, flags, NFC_CMD_GET_TARGET);
  58         if (!hdr)
  59                 return -EMSGSIZE;
  60
  61         genl_dump_check_consistent(cb, hdr, &nfc_genl_family);
  62
  63         NLA_PUT_U32(msg, NFC_ATTR_TARGET_INDEX, target->idx);
  64         NLA_PUT_U32(msg, NFC_ATTR_PROTOCOLS,
  65                                 target->supported_protocols);
  66         NLA_PUT_U16(msg, NFC_ATTR_TARGET_SENS_RES, target->sens_res);
  67         NLA_PUT_U8(msg, NFC_ATTR_TARGET_SEL_RES, target->sel_res);
  68
  69         return genlmsg_end(msg, hdr);
  70
  71 nla_put_failure:
  72         genlmsg_cancel(msg, hdr);
  73         return -EMSGSIZE;
  74 }
  75
  76 static struct nfc_dev *__get_device_from_cb(struct netlink_callback *cb)
  77 {
  78         struct nfc_dev *dev;
  79         int rc;
  80         u32 idx;
  81
  82         rc = nlmsg_parse(cb->nlh, GENL_HDRLEN + nfc_genl_family.hdrsize,
  83                                                 nfc_genl_family.attrbuf,
  84                                                 nfc_genl_family.maxattr,
  85                                                 nfc_genl_policy);
  86         if (rc < 0)
  87                 return ERR_PTR(rc);
  88
  89         if (!nfc_genl_family.attrbuf[NFC_ATTR_DEVICE_INDEX])
  90                 return ERR_PTR(-EINVAL);
  91
  92         idx = nla_get_u32(nfc_genl_family.attrbuf[NFC_ATTR_DEVICE_INDEX]);
  93
  94         dev = nfc_get_device(idx);
  95         if (!dev)
  96                 return ERR_PTR(-ENODEV);
  97
  98         return dev;
  99 }
 100
 101 static int nfc_genl_dump_targets(struct sk_buff *skb,
 102                                 struct netlink_callback *cb)
 103 {
 104         int i = cb->args[0];
 105         struct nfc_dev *dev = (struct nfc_dev *) cb->args[1];
 106         int rc;
 107
 108         nfc_dbg("entry");
 109
 110         if (!dev) {
 111                 dev = __get_device_from_cb(cb);
 112                 if (IS_ERR(dev))
 113                         return PTR_ERR(dev);
 114
 115                 cb->args[1] = (long) dev;
 116         }
 117
 118         spin_lock_bh(&dev->targets_lock);
 119
 120         cb->seq = dev->targets_generation;
 121
 122         while (i < dev->n_targets) {
 123                 rc = nfc_genl_send_target(skb, &dev->targets[i], cb,
 124                                                                 NLM_F_MULTI);
 125                 if (rc < 0)
 126                         break;
 127
 128                 i++;
 129         }
 130
 131         spin_unlock_bh(&dev->targets_lock);
 132
 133         cb->args[0] = i;
 134
 135         return skb->len;
 136 }
 137
 138 static int nfc_genl_dump_targets_done(struct netlink_callback *cb)
 139 {
 140         struct nfc_dev *dev = (struct nfc_dev *) cb->args[1];
 141
 142         nfc_dbg("entry");
 143
 144         if (dev)
 145                 nfc_put_device(dev);
 146
 147         return 0;
 148 }
 149
 150 int nfc_genl_targets_found(struct nfc_dev *dev)
 151 {
 152         struct sk_buff *msg;
 153         void *hdr;
 154
 155         nfc_dbg("entry");
 156
 157         dev->genl_data.poll_req_pid = 0;
 158
 159         msg = nlmsg_new(NLMSG_GOODSIZE, GFP_ATOMIC);
 160         if (!msg)
 161                 return -ENOMEM;
 162
 163         hdr = genlmsg_put(msg, 0, 0, &nfc_genl_family, 0,
 164                                 NFC_EVENT_TARGETS_FOUND);
 165         if (!hdr)
 166                 goto free_msg;
 167
 168         NLA_PUT_U32(msg, NFC_ATTR_DEVICE_INDEX, dev->idx);
 169
 170         genlmsg_end(msg, hdr);
 171
 172         return genlmsg_multicast(msg, 0, nfc_genl_event_mcgrp.id, GFP_ATOMIC);
 173
 174 nla_put_failure:
 175         genlmsg_cancel(msg, hdr);
 176 free_msg:
 177         nlmsg_free(msg);
 178         return -EMSGSIZE;
 179 }
 180
 181 int nfc_genl_device_added(struct nfc_dev *dev)
 182 {
 183         struct sk_buff *msg;
 184         void *hdr;
 185
 186         nfc_dbg("entry");
 187
 188         msg = nlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL);
 189         if (!msg)
 190                 return -ENOMEM;
 191
 192         hdr = genlmsg_put(msg, 0, 0, &nfc_genl_family, 0,
 193                                 NFC_EVENT_DEVICE_ADDED);
 194         if (!hdr)
 195                 goto free_msg;
 196
 197         NLA_PUT_STRING(msg, NFC_ATTR_DEVICE_NAME, nfc_device_name(dev));
 198         NLA_PUT_U32(msg, NFC_ATTR_DEVICE_INDEX, dev->idx);
 199         NLA_PUT_U32(msg, NFC_ATTR_PROTOCOLS, dev->supported_protocols);
 200
 201         genlmsg_end(msg, hdr);
 202
 203         genlmsg_multicast(msg, 0, nfc_genl_event_mcgrp.id, GFP_KERNEL);
 204
 205         return 0;
 206
 207 nla_put_failure:
 208         genlmsg_cancel(msg, hdr);
 209 free_msg:
 210         nlmsg_free(msg);
 211         return -EMSGSIZE;
 212 }
 213
 214 int nfc_genl_device_removed(struct nfc_dev *dev)
 215 {
 216         struct sk_buff *msg;
 217         void *hdr;
 218
 219         nfc_dbg("entry");
 220
 221         msg = nlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL);
 222         if (!msg)
 223                 return -ENOMEM;
 224
 225         hdr = genlmsg_put(msg, 0, 0, &nfc_genl_family, 0,
 226                                 NFC_EVENT_DEVICE_REMOVED);
 227         if (!hdr)
 228                 goto free_msg;
 229
 230         NLA_PUT_U32(msg, NFC_ATTR_DEVICE_INDEX, dev->idx);
 231
 232         genlmsg_end(msg, hdr);
 233
 234         genlmsg_multicast(msg, 0, nfc_genl_event_mcgrp.id, GFP_KERNEL);
 235
 236         return 0;
 237
 238 nla_put_failure:
 239         genlmsg_cancel(msg, hdr);
 240 free_msg:
 241         nlmsg_free(msg);
 242         return -EMSGSIZE;
 243 }
 244
 245 static int nfc_genl_send_device(struct sk_buff *msg, struct nfc_dev *dev,
 246                                                 u32 pid, u32 seq,
 247                                                 struct netlink_callback *cb,
 248                                                 int flags)
 249 {
 250         void *hdr;
 251
 252         nfc_dbg("entry");
 253
 254         hdr = genlmsg_put(msg, pid, seq, &nfc_genl_family, flags,
 255                                                         NFC_CMD_GET_DEVICE);
 256         if (!hdr)
 257                 return -EMSGSIZE;
 258
 259         if (cb)
 260                 genl_dump_check_consistent(cb, hdr, &nfc_genl_family);
 261
 262         NLA_PUT_STRING(msg, NFC_ATTR_DEVICE_NAME, nfc_device_name(dev));
 263         NLA_PUT_U32(msg, NFC_ATTR_DEVICE_INDEX, dev->idx);
 264         NLA_PUT_U32(msg, NFC_ATTR_PROTOCOLS, dev->supported_protocols);
 265
 266         return genlmsg_end(msg, hdr);
 267
 268 nla_put_failure:
 269         genlmsg_cancel(msg, hdr);
 270         return -EMSGSIZE;
 271 }
 272
 273 static int nfc_genl_dump_devices(struct sk_buff *skb,
 274                                 struct netlink_callback *cb)
 275 {
 276         struct class_dev_iter *iter = (struct class_dev_iter *) cb->args[0];
 277         struct nfc_dev *dev = (struct nfc_dev *) cb->args[1];
 278         bool first_call = false;
 279
 280         nfc_dbg("entry");
 281
 282         if (!iter) {
 283                 first_call = true;
 284                 iter = kmalloc(sizeof(struct class_dev_iter), GFP_KERNEL);
 285                 if (!iter)
 286                         return -ENOMEM;
 287                 cb->args[0] = (long) iter;
 288         }
 289
 290         mutex_lock(&nfc_devlist_mutex);
 291
 292         cb->seq = nfc_devlist_generation;
 293
 294         if (first_call) {
 295                 nfc_device_iter_init(iter);
 296                 dev = nfc_device_iter_next(iter);
 297         }
 298
 299         while (dev) {
 300                 int rc;
 301
 302                 rc = nfc_genl_send_device(skb, dev, NETLINK_CB(cb->skb).pid,
 303                                                         cb->nlh->nlmsg_seq,
 304                                                         cb, NLM_F_MULTI);
 305                 if (rc < 0)
 306                         break;
 307
 308                 dev = nfc_device_iter_next(iter);
 309         }
 310
 311         mutex_unlock(&nfc_devlist_mutex);
 312
 313         cb->args[1] = (long) dev;
 314
 315         return skb->len;
 316 }
 317
 318 static int nfc_genl_dump_devices_done(struct netlink_callback *cb)
 319 {
 320         struct class_dev_iter *iter = (struct class_dev_iter *) cb->args[0];
 321
 322         nfc_dbg("entry");
 323
 324         nfc_device_iter_exit(iter);
 325         kfree(iter);
 326
 327         return 0;
 328 }
 329
 330 static int nfc_genl_get_device(struct sk_buff *skb, struct genl_info *info)
 331 {
 332         struct sk_buff *msg;
 333         struct nfc_dev *dev;
 334         u32 idx;
 335         int rc = -ENOBUFS;
 336
 337         nfc_dbg("entry");
 338
 339         if (!info->attrs[NFC_ATTR_DEVICE_INDEX])
 340                 return -EINVAL;
 341
 342         idx = nla_get_u32(info->attrs[NFC_ATTR_DEVICE_INDEX]);
 343
 344         dev = nfc_get_device(idx);
 345         if (!dev)
 346                 return -ENODEV;
 347
 348         msg = nlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL);
 349         if (!msg) {
 350                 rc = -ENOMEM;
 351                 goto out_putdev;
 352         }
 353
 354         rc = nfc_genl_send_device(msg, dev, info->snd_pid, info->snd_seq,
 355                                                                 NULL, 0);
 356         if (rc < 0)
 357                 goto out_free;
 358
 359         nfc_put_device(dev);
 360
 361         return genlmsg_reply(msg, info);
 362
 363 out_free:
 364         nlmsg_free(msg);
 365 out_putdev:
 366         nfc_put_device(dev);
 367         return rc;
 368 }
 369
 370 static int nfc_genl_start_poll(struct sk_buff *skb, struct genl_info *info)
 371 {
 372         struct nfc_dev *dev;
 373         int rc;
 374         u32 idx;
 375         u32 protocols;
 376
 377         nfc_dbg("entry");
 378
 379         if (!info->attrs[NFC_ATTR_DEVICE_INDEX] ||
 380                 !info->attrs[NFC_ATTR_PROTOCOLS])
 381                 return -EINVAL;
 382
 383         idx = nla_get_u32(info->attrs[NFC_ATTR_DEVICE_INDEX]);
 384         protocols = nla_get_u32(info->attrs[NFC_ATTR_PROTOCOLS]);
 385
 386         dev = nfc_get_device(idx);
 387         if (!dev)
 388                 return -ENODEV;
 389
 390         mutex_lock(&dev->genl_data.genl_data_mutex);
 391
 392         rc = nfc_start_poll(dev, protocols);
 393         if (!rc)
 394                 dev->genl_data.poll_req_pid = info->snd_pid;
 395
 396         mutex_unlock(&dev->genl_data.genl_data_mutex);
 397
 398         nfc_put_device(dev);
 399         return rc;
 400 }
 401
 402 static int nfc_genl_stop_poll(struct sk_buff *skb, struct genl_info *info)
 403 {
 404         struct nfc_dev *dev;
 405         int rc;
 406         u32 idx;
 407
 408         nfc_dbg("entry");
 409
 410         if (!info->attrs[NFC_ATTR_DEVICE_INDEX])
 411                 return -EINVAL;
 412
 413         idx = nla_get_u32(info->attrs[NFC_ATTR_DEVICE_INDEX]);
 414
 415         dev = nfc_get_device(idx);
 416         if (!dev)
 417                 return -ENODEV;
 418
 419         mutex_lock(&dev->genl_data.genl_data_mutex);
 420
 421         if (dev->genl_data.poll_req_pid != info->snd_pid) {
 422                 rc = -EBUSY;
 423                 goto out;
 424         }
 425
 426         rc = nfc_stop_poll(dev);
 427         dev->genl_data.poll_req_pid = 0;
 428
 429 out:
 430         mutex_unlock(&dev->genl_data.genl_data_mutex);
 431         nfc_put_device(dev);
 432         return rc;
 433 }
 434
 435 static struct genl_ops nfc_genl_ops[] = {
 436         {
 437                 .cmd = NFC_CMD_GET_DEVICE,
 438                 .doit = nfc_genl_get_device,
 439                 .dumpit = nfc_genl_dump_devices,
 440                 .done = nfc_genl_dump_devices_done,
 441                 .policy = nfc_genl_policy,
 442         },
 443         {
 444                 .cmd = NFC_CMD_START_POLL,
 445                 .doit = nfc_genl_start_poll,
 446                 .policy = nfc_genl_policy,
 447         },
 448         {
 449                 .cmd = NFC_CMD_STOP_POLL,
 450                 .doit = nfc_genl_stop_poll,
 451                 .policy = nfc_genl_policy,
 452         },
 453         {
 454                 .cmd = NFC_CMD_GET_TARGET,
 455                 .dumpit = nfc_genl_dump_targets,
 456                 .done = nfc_genl_dump_targets_done,
 457                 .policy = nfc_genl_policy,
 458         },
 459 };
 460
 461 static int nfc_genl_rcv_nl_event(struct notifier_block *this,
 462                                                 unsigned long event, void *ptr)
 463 {
 464         struct netlink_notify *n = ptr;
 465         struct class_dev_iter iter;
 466         struct nfc_dev *dev;
 467
 468         if (event != NETLINK_URELEASE || n->protocol != NETLINK_GENERIC)
 469                 goto out;
 470
 471         nfc_dbg("NETLINK_URELEASE event from id %d", n->pid);
 472
 473         nfc_device_iter_init(&iter);
 474         dev = nfc_device_iter_next(&iter);
 475
 476         while (dev) {
 477                 mutex_lock(&dev->genl_data.genl_data_mutex);
 478                 if (dev->genl_data.poll_req_pid == n->pid) {
 479                         nfc_stop_poll(dev);
 480                         dev->genl_data.poll_req_pid = 0;
 481                 }
 482                 mutex_unlock(&dev->genl_data.genl_data_mutex);
 483                 dev = nfc_device_iter_next(&iter);
 484         }
 485
 486         nfc_device_iter_exit(&iter);
 487
 488 out:
 489         return NOTIFY_DONE;
 490 }
 491
 492 void nfc_genl_data_init(struct nfc_genl_data *genl_data)
 493 {
 494         genl_data->poll_req_pid = 0;
 495         mutex_init(&genl_data->genl_data_mutex);
 496 }
 497
 498 void nfc_genl_data_exit(struct nfc_genl_data *genl_data)
 499 {
 500         mutex_destroy(&genl_data->genl_data_mutex);
 501 }
 502
 503 static struct notifier_block nl_notifier = {
 504         .notifier_call  = nfc_genl_rcv_nl_event,
 505 };
 506
 507 /**
 508  * nfc_genl_init() - Initialize netlink interface
 509  *
 510  * This initialization function registers the nfc netlink family.
 511  */
 512 int __init nfc_genl_init(void)
 513 {
 514         int rc;
 515
 516         rc = genl_register_family_with_ops(&nfc_genl_family, nfc_genl_ops,
 517                                         ARRAY_SIZE(nfc_genl_ops));
 518         if (rc)
 519                 return rc;
 520
 521         rc = genl_register_mc_group(&nfc_genl_family, &nfc_genl_event_mcgrp);
 522
 523         netlink_register_notifier(&nl_notifier);
 524
 525         return rc;
 526 }
 527
 528 /**
 529  * nfc_genl_exit() - Deinitialize netlink interface
 530  *
 531  * This exit function unregisters the nfc netlink family.
 532  */
 533 void nfc_genl_exit(void)
 534 {
 535         netlink_unregister_notifier(&nl_notifier);
 536         genl_unregister_family(&nfc_genl_family);
 537 }