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 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  25
  26 #include <net/genetlink.h>
  27 #include <linux/nfc.h>
  28 #include <linux/slab.h>
  29
  30 #include "nfc.h"
  31
  32 static struct genl_multicast_group nfc_genl_event_mcgrp = {
  33         .name = NFC_GENL_MCAST_EVENT_NAME,
  34 };
  35
  36 struct genl_family nfc_genl_family = {
  37         .id = GENL_ID_GENERATE,
  38         .hdrsize = 0,
  39         .name = NFC_GENL_NAME,
  40         .version = NFC_GENL_VERSION,
  41         .maxattr = NFC_ATTR_MAX,
  42 };
  43
  44 static const struct nla_policy nfc_genl_policy[NFC_ATTR_MAX + 1] = {
  45         [NFC_ATTR_DEVICE_INDEX] = { .type = NLA_U32 },
  46         [NFC_ATTR_DEVICE_NAME] = { .type = NLA_STRING,
  47                                 .len = NFC_DEVICE_NAME_MAXSIZE },
  48         [NFC_ATTR_PROTOCOLS] = { .type = NLA_U32 },
  49 };
  50
  51 static int nfc_genl_send_target(struct sk_buff *msg, struct nfc_target *target,
  52                                         struct netlink_callback *cb, int flags)
  53 {
  54         void *hdr;
  55
  56         pr_debug("entry\n");
  57
  58         hdr = genlmsg_put(msg, NETLINK_CB(cb->skb).pid, cb->nlh->nlmsg_seq,
  59                                 &nfc_genl_family, flags, NFC_CMD_GET_TARGET);
  60         if (!hdr)
  61                 return -EMSGSIZE;
  62
  63         genl_dump_check_consistent(cb, hdr, &nfc_genl_family);
  64
  65         NLA_PUT_U32(msg, NFC_ATTR_TARGET_INDEX, target->idx);
  66         NLA_PUT_U32(msg, NFC_ATTR_PROTOCOLS,
  67                                 target->supported_protocols);
  68         NLA_PUT_U16(msg, NFC_ATTR_TARGET_SENS_RES, target->sens_res);
  69         NLA_PUT_U8(msg, NFC_ATTR_TARGET_SEL_RES, target->sel_res);
  70
  71         return genlmsg_end(msg, hdr);
  72
  73 nla_put_failure:
  74         genlmsg_cancel(msg, hdr);
  75         return -EMSGSIZE;
  76 }
  77
  78 static struct nfc_dev *__get_device_from_cb(struct netlink_callback *cb)
  79 {
  80         struct nfc_dev *dev;
  81         int rc;
  82         u32 idx;
  83
  84         rc = nlmsg_parse(cb->nlh, GENL_HDRLEN + nfc_genl_family.hdrsize,
  85                                                 nfc_genl_family.attrbuf,
  86                                                 nfc_genl_family.maxattr,
  87                                                 nfc_genl_policy);
  88         if (rc < 0)
  89                 return ERR_PTR(rc);
  90
  91         if (!nfc_genl_family.attrbuf[NFC_ATTR_DEVICE_INDEX])
  92                 return ERR_PTR(-EINVAL);
  93
  94         idx = nla_get_u32(nfc_genl_family.attrbuf[NFC_ATTR_DEVICE_INDEX]);
  95
  96         dev = nfc_get_device(idx);
  97         if (!dev)
  98                 return ERR_PTR(-ENODEV);
  99
 100         return dev;
 101 }
 102
 103 static int nfc_genl_dump_targets(struct sk_buff *skb,
 104                                 struct netlink_callback *cb)
 105 {
 106         int i = cb->args[0];
 107         struct nfc_dev *dev = (struct nfc_dev *) cb->args[1];
 108         int rc;
 109
 110         pr_debug("entry\n");
 111
 112         if (!dev) {
 113                 dev = __get_device_from_cb(cb);
 114                 if (IS_ERR(dev))
 115                         return PTR_ERR(dev);
 116
 117                 cb->args[1] = (long) dev;
 118         }
 119
 120         spin_lock_bh(&dev->targets_lock);
 121
 122         cb->seq = dev->targets_generation;
 123
 124         while (i < dev->n_targets) {
 125                 rc = nfc_genl_send_target(skb, &dev->targets[i], cb,
 126                                                                 NLM_F_MULTI);
 127                 if (rc < 0)
 128                         break;
 129
 130                 i++;
 131         }
 132
 133         spin_unlock_bh(&dev->targets_lock);
 134
 135         cb->args[0] = i;
 136
 137         return skb->len;
 138 }
 139
 140 static int nfc_genl_dump_targets_done(struct netlink_callback *cb)
 141 {
 142         struct nfc_dev *dev = (struct nfc_dev *) cb->args[1];
 143
 144         pr_debug("entry\n");
 145
 146         if (dev)
 147                 nfc_put_device(dev);
 148
 149         return 0;
 150 }
 151
 152 int nfc_genl_targets_found(struct nfc_dev *dev)
 153 {
 154         struct sk_buff *msg;
 155         void *hdr;
 156
 157         pr_debug("entry\n");
 158
 159         dev->genl_data.poll_req_pid = 0;
 160
 161         msg = nlmsg_new(NLMSG_GOODSIZE, GFP_ATOMIC);
 162         if (!msg)
 163                 return -ENOMEM;
 164
 165         hdr = genlmsg_put(msg, 0, 0, &nfc_genl_family, 0,
 166                                 NFC_EVENT_TARGETS_FOUND);
 167         if (!hdr)
 168                 goto free_msg;
 169
 170         NLA_PUT_U32(msg, NFC_ATTR_DEVICE_INDEX, dev->idx);
 171
 172         genlmsg_end(msg, hdr);
 173
 174         return genlmsg_multicast(msg, 0, nfc_genl_event_mcgrp.id, GFP_ATOMIC);
 175
 176 nla_put_failure:
 177         genlmsg_cancel(msg, hdr);
 178 free_msg:
 179         nlmsg_free(msg);
 180         return -EMSGSIZE;
 181 }
 182
 183 int nfc_genl_device_added(struct nfc_dev *dev)
 184 {
 185         struct sk_buff *msg;
 186         void *hdr;
 187
 188         pr_debug("entry\n");
 189
 190         msg = nlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL);
 191         if (!msg)
 192                 return -ENOMEM;
 193
 194         hdr = genlmsg_put(msg, 0, 0, &nfc_genl_family, 0,
 195                                 NFC_EVENT_DEVICE_ADDED);
 196         if (!hdr)
 197                 goto free_msg;
 198
 199         NLA_PUT_STRING(msg, NFC_ATTR_DEVICE_NAME, nfc_device_name(dev));
 200         NLA_PUT_U32(msg, NFC_ATTR_DEVICE_INDEX, dev->idx);
 201         NLA_PUT_U32(msg, NFC_ATTR_PROTOCOLS, dev->supported_protocols);
 202
 203         genlmsg_end(msg, hdr);
 204
 205         genlmsg_multicast(msg, 0, nfc_genl_event_mcgrp.id, GFP_KERNEL);
 206
 207         return 0;
 208
 209 nla_put_failure:
 210         genlmsg_cancel(msg, hdr);
 211 free_msg:
 212         nlmsg_free(msg);
 213         return -EMSGSIZE;
 214 }
 215
 216 int nfc_genl_device_removed(struct nfc_dev *dev)
 217 {
 218         struct sk_buff *msg;
 219         void *hdr;
 220
 221         pr_debug("entry\n");
 222
 223         msg = nlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL);
 224         if (!msg)
 225                 return -ENOMEM;
 226
 227         hdr = genlmsg_put(msg, 0, 0, &nfc_genl_family, 0,
 228                                 NFC_EVENT_DEVICE_REMOVED);
 229         if (!hdr)
 230                 goto free_msg;
 231
 232         NLA_PUT_U32(msg, NFC_ATTR_DEVICE_INDEX, dev->idx);
 233
 234         genlmsg_end(msg, hdr);
 235
 236         genlmsg_multicast(msg, 0, nfc_genl_event_mcgrp.id, GFP_KERNEL);
 237
 238         return 0;
 239
 240 nla_put_failure:
 241         genlmsg_cancel(msg, hdr);
 242 free_msg:
 243         nlmsg_free(msg);
 244         return -EMSGSIZE;
 245 }
 246
 247 static int nfc_genl_send_device(struct sk_buff *msg, struct nfc_dev *dev,
 248                                                 u32 pid, u32 seq,
 249                                                 struct netlink_callback *cb,
 250                                                 int flags)
 251 {
 252         void *hdr;
 253
 254         pr_debug("entry\n");
 255
 256         hdr = genlmsg_put(msg, pid, seq, &nfc_genl_family, flags,
 257                                                         NFC_CMD_GET_DEVICE);
 258         if (!hdr)
 259                 return -EMSGSIZE;
 260
 261         if (cb)
 262                 genl_dump_check_consistent(cb, hdr, &nfc_genl_family);
 263
 264         NLA_PUT_STRING(msg, NFC_ATTR_DEVICE_NAME, nfc_device_name(dev));
 265         NLA_PUT_U32(msg, NFC_ATTR_DEVICE_INDEX, dev->idx);
 266         NLA_PUT_U32(msg, NFC_ATTR_PROTOCOLS, dev->supported_protocols);
 267
 268         return genlmsg_end(msg, hdr);
 269
 270 nla_put_failure:
 271         genlmsg_cancel(msg, hdr);
 272         return -EMSGSIZE;
 273 }
 274
 275 static int nfc_genl_dump_devices(struct sk_buff *skb,
 276                                 struct netlink_callback *cb)
 277 {
 278         struct class_dev_iter *iter = (struct class_dev_iter *) cb->args[0];
 279         struct nfc_dev *dev = (struct nfc_dev *) cb->args[1];
 280         bool first_call = false;
 281
 282         pr_debug("entry\n");
 283
 284         if (!iter) {
 285                 first_call = true;
 286                 iter = kmalloc(sizeof(struct class_dev_iter), GFP_KERNEL);
 287                 if (!iter)
 288                         return -ENOMEM;
 289                 cb->args[0] = (long) iter;
 290         }
 291
 292         mutex_lock(&nfc_devlist_mutex);
 293
 294         cb->seq = nfc_devlist_generation;
 295
 296         if (first_call) {
 297                 nfc_device_iter_init(iter);
 298                 dev = nfc_device_iter_next(iter);
 299         }
 300
 301         while (dev) {
 302                 int rc;
 303
 304                 rc = nfc_genl_send_device(skb, dev, NETLINK_CB(cb->skb).pid,
 305                                                         cb->nlh->nlmsg_seq,
 306                                                         cb, NLM_F_MULTI);
 307                 if (rc < 0)
 308                         break;
 309
 310                 dev = nfc_device_iter_next(iter);
 311         }
 312
 313         mutex_unlock(&nfc_devlist_mutex);
 314
 315         cb->args[1] = (long) dev;
 316
 317         return skb->len;
 318 }
 319
 320 static int nfc_genl_dump_devices_done(struct netlink_callback *cb)
 321 {
 322         struct class_dev_iter *iter = (struct class_dev_iter *) cb->args[0];
 323
 324         pr_debug("entry\n");
 325
 326         nfc_device_iter_exit(iter);
 327         kfree(iter);
 328
 329         return 0;
 330 }
 331
 332 static int nfc_genl_get_device(struct sk_buff *skb, struct genl_info *info)
 333 {
 334         struct sk_buff *msg;
 335         struct nfc_dev *dev;
 336         u32 idx;
 337         int rc = -ENOBUFS;
 338
 339         pr_debug("entry\n");
 340
 341         if (!info->attrs[NFC_ATTR_DEVICE_INDEX])
 342                 return -EINVAL;
 343
 344         idx = nla_get_u32(info->attrs[NFC_ATTR_DEVICE_INDEX]);
 345
 346         dev = nfc_get_device(idx);
 347         if (!dev)
 348                 return -ENODEV;
 349
 350         msg = nlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL);
 351         if (!msg) {
 352                 rc = -ENOMEM;
 353                 goto out_putdev;
 354         }
 355
 356         rc = nfc_genl_send_device(msg, dev, info->snd_pid, info->snd_seq,
 357                                                                 NULL, 0);
 358         if (rc < 0)
 359                 goto out_free;
 360
 361         nfc_put_device(dev);
 362
 363         return genlmsg_reply(msg, info);
 364
 365 out_free:
 366         nlmsg_free(msg);
 367 out_putdev:
 368         nfc_put_device(dev);
 369         return rc;
 370 }
 371
 372 static int nfc_genl_dev_up(struct sk_buff *skb, struct genl_info *info)
 373 {
 374         struct nfc_dev *dev;
 375         int rc;
 376         u32 idx;
 377
 378         pr_debug("entry\n");
 379
 380         if (!info->attrs[NFC_ATTR_DEVICE_INDEX])
 381                 return -EINVAL;
 382
 383         idx = nla_get_u32(info->attrs[NFC_ATTR_DEVICE_INDEX]);
 384
 385         dev = nfc_get_device(idx);
 386         if (!dev)
 387                 return -ENODEV;
 388
 389         rc = nfc_dev_up(dev);
 390
 391         nfc_put_device(dev);
 392         return rc;
 393 }
 394
 395 static int nfc_genl_dev_down(struct sk_buff *skb, struct genl_info *info)
 396 {
 397         struct nfc_dev *dev;
 398         int rc;
 399         u32 idx;
 400
 401         pr_debug("entry\n");
 402
 403         if (!info->attrs[NFC_ATTR_DEVICE_INDEX])
 404                 return -EINVAL;
 405
 406         idx = nla_get_u32(info->attrs[NFC_ATTR_DEVICE_INDEX]);
 407
 408         dev = nfc_get_device(idx);
 409         if (!dev)
 410                 return -ENODEV;
 411
 412         rc = nfc_dev_down(dev);
 413
 414         nfc_put_device(dev);
 415         return rc;
 416 }
 417
 418 static int nfc_genl_start_poll(struct sk_buff *skb, struct genl_info *info)
 419 {
 420         struct nfc_dev *dev;
 421         int rc;
 422         u32 idx;
 423         u32 protocols;
 424
 425         pr_debug("entry\n");
 426
 427         if (!info->attrs[NFC_ATTR_DEVICE_INDEX] ||
 428                 !info->attrs[NFC_ATTR_PROTOCOLS])
 429                 return -EINVAL;
 430
 431         idx = nla_get_u32(info->attrs[NFC_ATTR_DEVICE_INDEX]);
 432         protocols = nla_get_u32(info->attrs[NFC_ATTR_PROTOCOLS]);
 433
 434         dev = nfc_get_device(idx);
 435         if (!dev)
 436                 return -ENODEV;
 437
 438         mutex_lock(&dev->genl_data.genl_data_mutex);
 439
 440         rc = nfc_start_poll(dev, protocols);
 441         if (!rc)
 442                 dev->genl_data.poll_req_pid = info->snd_pid;
 443
 444         mutex_unlock(&dev->genl_data.genl_data_mutex);
 445
 446         nfc_put_device(dev);
 447         return rc;
 448 }
 449
 450 static int nfc_genl_stop_poll(struct sk_buff *skb, struct genl_info *info)
 451 {
 452         struct nfc_dev *dev;
 453         int rc;
 454         u32 idx;
 455
 456         pr_debug("entry\n");
 457
 458         if (!info->attrs[NFC_ATTR_DEVICE_INDEX])
 459                 return -EINVAL;
 460
 461         idx = nla_get_u32(info->attrs[NFC_ATTR_DEVICE_INDEX]);
 462
 463         dev = nfc_get_device(idx);
 464         if (!dev)
 465                 return -ENODEV;
 466
 467         mutex_lock(&dev->genl_data.genl_data_mutex);
 468
 469         if (dev->genl_data.poll_req_pid != info->snd_pid) {
 470                 rc = -EBUSY;
 471                 goto out;
 472         }
 473
 474         rc = nfc_stop_poll(dev);
 475         dev->genl_data.poll_req_pid = 0;
 476
 477 out:
 478         mutex_unlock(&dev->genl_data.genl_data_mutex);
 479         nfc_put_device(dev);
 480         return rc;
 481 }
 482
 483 static struct genl_ops nfc_genl_ops[] = {
 484         {
 485                 .cmd = NFC_CMD_GET_DEVICE,
 486                 .doit = nfc_genl_get_device,
 487                 .dumpit = nfc_genl_dump_devices,
 488                 .done = nfc_genl_dump_devices_done,
 489                 .policy = nfc_genl_policy,
 490         },
 491         {
 492                 .cmd = NFC_CMD_DEV_UP,
 493                 .doit = nfc_genl_dev_up,
 494                 .policy = nfc_genl_policy,
 495         },
 496         {
 497                 .cmd = NFC_CMD_DEV_DOWN,
 498                 .doit = nfc_genl_dev_down,
 499                 .policy = nfc_genl_policy,
 500         },
 501         {
 502                 .cmd = NFC_CMD_START_POLL,
 503                 .doit = nfc_genl_start_poll,
 504                 .policy = nfc_genl_policy,
 505         },
 506         {
 507                 .cmd = NFC_CMD_STOP_POLL,
 508                 .doit = nfc_genl_stop_poll,
 509                 .policy = nfc_genl_policy,
 510         },
 511         {
 512                 .cmd = NFC_CMD_GET_TARGET,
 513                 .dumpit = nfc_genl_dump_targets,
 514                 .done = nfc_genl_dump_targets_done,
 515                 .policy = nfc_genl_policy,
 516         },
 517 };
 518
 519 static int nfc_genl_rcv_nl_event(struct notifier_block *this,
 520                                                 unsigned long event, void *ptr)
 521 {
 522         struct netlink_notify *n = ptr;
 523         struct class_dev_iter iter;
 524         struct nfc_dev *dev;
 525
 526         if (event != NETLINK_URELEASE || n->protocol != NETLINK_GENERIC)
 527                 goto out;
 528
 529         pr_debug("NETLINK_URELEASE event from id %d\n", n->pid);
 530
 531         nfc_device_iter_init(&iter);
 532         dev = nfc_device_iter_next(&iter);
 533
 534         while (dev) {
 535                 mutex_lock(&dev->genl_data.genl_data_mutex);
 536                 if (dev->genl_data.poll_req_pid == n->pid) {
 537                         nfc_stop_poll(dev);
 538                         dev->genl_data.poll_req_pid = 0;
 539                 }
 540                 mutex_unlock(&dev->genl_data.genl_data_mutex);
 541                 dev = nfc_device_iter_next(&iter);
 542         }
 543
 544         nfc_device_iter_exit(&iter);
 545
 546 out:
 547         return NOTIFY_DONE;
 548 }
 549
 550 void nfc_genl_data_init(struct nfc_genl_data *genl_data)
 551 {
 552         genl_data->poll_req_pid = 0;
 553         mutex_init(&genl_data->genl_data_mutex);
 554 }
 555
 556 void nfc_genl_data_exit(struct nfc_genl_data *genl_data)
 557 {
 558         mutex_destroy(&genl_data->genl_data_mutex);
 559 }
 560
 561 static struct notifier_block nl_notifier = {
 562         .notifier_call  = nfc_genl_rcv_nl_event,
 563 };
 564
 565 /**
 566  * nfc_genl_init() - Initialize netlink interface
 567  *
 568  * This initialization function registers the nfc netlink family.
 569  */
 570 int __init nfc_genl_init(void)
 571 {
 572         int rc;
 573
 574         rc = genl_register_family_with_ops(&nfc_genl_family, nfc_genl_ops,
 575                                         ARRAY_SIZE(nfc_genl_ops));
 576         if (rc)
 577                 return rc;
 578
 579         rc = genl_register_mc_group(&nfc_genl_family, &nfc_genl_event_mcgrp);
 580
 581         netlink_register_notifier(&nl_notifier);
 582
 583         return rc;
 584 }
 585
 586 /**
 587  * nfc_genl_exit() - Deinitialize netlink interface
 588  *
 589  * This exit function unregisters the nfc netlink family.
 590  */
 591 void nfc_genl_exit(void)
 592 {
 593         netlink_unregister_notifier(&nl_notifier);
 594         genl_unregister_family(&nfc_genl_family);
 595 }