drivers/w1/w1_netlink.c

   1 /*
   2  * w1_netlink.c
   3  *
   4  * Copyright (c) 2003 Evgeniy Polyakov <zbr@ioremap.net>
   5  *
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program; if not, write to the Free Software
  19  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  20  */
  21
  22 #include <linux/slab.h>
  23 #include <linux/skbuff.h>
  24 #include <linux/netlink.h>
  25 #include <linux/connector.h>
  26
  27 #include "w1.h"
  28 #include "w1_log.h"
  29 #include "w1_netlink.h"
  30
  31 #if defined(CONFIG_W1_CON) && (defined(CONFIG_CONNECTOR) || (defined(CONFIG_CONNECTOR_MODULE) && defined(CONFIG_W1_MODULE)))
  32 void w1_netlink_send(struct w1_master *dev, struct w1_netlink_msg *msg)
  33 {
  34         char buf[sizeof(struct cn_msg) + sizeof(struct w1_netlink_msg)];
  35         struct cn_msg *m = (struct cn_msg *)buf;
  36         struct w1_netlink_msg *w = (struct w1_netlink_msg *)(m+1);
  37
  38         memset(buf, 0, sizeof(buf));
  39
  40         m->id.idx = CN_W1_IDX;
  41         m->id.val = CN_W1_VAL;
  42
  43         m->seq = dev->seq++;
  44         m->len = sizeof(struct w1_netlink_msg);
  45
  46         memcpy(w, msg, sizeof(struct w1_netlink_msg));
  47
  48         cn_netlink_send(m, dev->portid, 0, GFP_KERNEL);
  49 }
  50
  51 static void w1_send_slave(struct w1_master *dev, u64 rn)
  52 {
  53         struct cn_msg *msg = dev->priv;
  54         struct w1_netlink_msg *hdr = (struct w1_netlink_msg *)(msg + 1);
  55         struct w1_netlink_cmd *cmd = (struct w1_netlink_cmd *)(hdr + 1);
  56         int avail;
  57         u64 *data;
  58
  59         avail = dev->priv_size - cmd->len;
  60
  61         if (avail < 8) {
  62                 msg->ack++;
  63                 cn_netlink_send(msg, dev->portid, 0, GFP_KERNEL);
  64
  65                 msg->len = sizeof(struct w1_netlink_msg) +
  66                         sizeof(struct w1_netlink_cmd);
  67                 hdr->len = sizeof(struct w1_netlink_cmd);
  68                 cmd->len = 0;
  69         }
  70
  71         data = (void *)(cmd + 1) + cmd->len;
  72
  73         *data = rn;
  74         cmd->len += 8;
  75         hdr->len += 8;
  76         msg->len += 8;
  77 }
  78
  79 static void w1_found_send_slave(struct w1_master *dev, u64 rn)
  80 {
  81         /* update kernel slave list */
  82         w1_slave_found(dev, rn);
  83
  84         w1_send_slave(dev, rn);
  85 }
  86
  87 /* Get the current slave list, or search (with or without alarm) */
  88 static int w1_get_slaves(struct w1_master *dev,
  89                 struct cn_msg *req_msg, struct w1_netlink_msg *req_hdr,
  90                 struct w1_netlink_cmd *req_cmd)
  91 {
  92         struct cn_msg *msg;
  93         struct w1_netlink_msg *hdr;
  94         struct w1_netlink_cmd *cmd;
  95         struct w1_slave *sl;
  96
  97         msg = kzalloc(PAGE_SIZE, GFP_KERNEL);
  98         if (!msg)
  99                 return -ENOMEM;
 100
 101         msg->id = req_msg->id;
 102         msg->seq = req_msg->seq;
 103         msg->ack = 0;
 104         msg->len = sizeof(struct w1_netlink_msg) +
 105                 sizeof(struct w1_netlink_cmd);
 106
 107         hdr = (struct w1_netlink_msg *)(msg + 1);
 108         cmd = (struct w1_netlink_cmd *)(hdr + 1);
 109
 110         hdr->type = W1_MASTER_CMD;
 111         hdr->id = req_hdr->id;
 112         hdr->len = sizeof(struct w1_netlink_cmd);
 113
 114         cmd->cmd = req_cmd->cmd;
 115         cmd->len = 0;
 116
 117         dev->priv = msg;
 118         dev->priv_size = PAGE_SIZE - msg->len - sizeof(struct cn_msg);
 119
 120         if (req_cmd->cmd == W1_CMD_LIST_SLAVES) {
 121                 __u64 rn;
 122                 mutex_lock(&dev->list_mutex);
 123                 list_for_each_entry(sl, &dev->slist, w1_slave_entry) {
 124                         memcpy(&rn, &sl->reg_num, sizeof(rn));
 125                         w1_send_slave(dev, rn);
 126                 }
 127                 mutex_unlock(&dev->list_mutex);
 128         } else {
 129                 w1_search_process_cb(dev, cmd->cmd == W1_CMD_ALARM_SEARCH ?
 130                         W1_ALARM_SEARCH : W1_SEARCH, w1_found_send_slave);
 131         }
 132
 133         msg->ack = 0;
 134         cn_netlink_send(msg, dev->portid, 0, GFP_KERNEL);
 135
 136         dev->priv = NULL;
 137         dev->priv_size = 0;
 138
 139         kfree(msg);
 140
 141         return 0;
 142 }
 143
 144 static int w1_send_read_reply(struct cn_msg *msg, struct w1_netlink_msg *hdr,
 145                 struct w1_netlink_cmd *cmd, u32 portid)
 146 {
 147         void *data;
 148         struct w1_netlink_msg *h;
 149         struct w1_netlink_cmd *c;
 150         struct cn_msg *cm;
 151         int err;
 152
 153         data = kzalloc(sizeof(struct cn_msg) +
 154                         sizeof(struct w1_netlink_msg) +
 155                         sizeof(struct w1_netlink_cmd) +
 156                         cmd->len, GFP_KERNEL);
 157         if (!data)
 158                 return -ENOMEM;
 159
 160         cm = (struct cn_msg *)(data);
 161         h = (struct w1_netlink_msg *)(cm + 1);
 162         c = (struct w1_netlink_cmd *)(h + 1);
 163
 164         memcpy(cm, msg, sizeof(struct cn_msg));
 165         memcpy(h, hdr, sizeof(struct w1_netlink_msg));
 166         memcpy(c, cmd, sizeof(struct w1_netlink_cmd));
 167
 168         cm->ack = msg->seq+1;
 169         cm->len = sizeof(struct w1_netlink_msg) +
 170                 sizeof(struct w1_netlink_cmd) + cmd->len;
 171
 172         h->len = sizeof(struct w1_netlink_cmd) + cmd->len;
 173
 174         memcpy(c->data, cmd->data, c->len);
 175
 176         err = cn_netlink_send(cm, portid, 0, GFP_KERNEL);
 177
 178         kfree(data);
 179
 180         return err;
 181 }
 182
 183 static int w1_process_command_io(struct w1_master *dev, struct cn_msg *msg,
 184                 struct w1_netlink_msg *hdr, struct w1_netlink_cmd *cmd)
 185 {
 186         int err = 0;
 187
 188         switch (cmd->cmd) {
 189         case W1_CMD_TOUCH:
 190                 w1_touch_block(dev, cmd->data, cmd->len);
 191                 w1_send_read_reply(msg, hdr, cmd, dev->portid);
 192                 break;
 193         case W1_CMD_READ:
 194                 w1_read_block(dev, cmd->data, cmd->len);
 195                 w1_send_read_reply(msg, hdr, cmd, dev->portid);
 196                 break;
 197         case W1_CMD_WRITE:
 198                 w1_write_block(dev, cmd->data, cmd->len);
 199                 break;
 200         default:
 201                 err = -EINVAL;
 202                 break;
 203         }
 204
 205         return err;
 206 }
 207
 208 static int w1_process_command_addremove(struct w1_master *dev,
 209         struct cn_msg *msg, struct w1_netlink_msg *hdr,
 210         struct w1_netlink_cmd *cmd)
 211 {
 212         struct w1_slave *sl;
 213         int err = 0;
 214         struct w1_reg_num *id;
 215
 216         if (cmd->len != 8)
 217                 return -EINVAL;
 218
 219         id = (struct w1_reg_num *)cmd->data;
 220
 221         sl = w1_slave_search_device(dev, id);
 222         switch (cmd->cmd) {
 223         case W1_CMD_SLAVE_ADD:
 224                 if (sl)
 225                         err = -EINVAL;
 226                 else
 227                         err = w1_attach_slave_device(dev, id);
 228                 break;
 229         case W1_CMD_SLAVE_REMOVE:
 230                 if (sl)
 231                         w1_slave_detach(sl);
 232                 else
 233                         err = -EINVAL;
 234                 break;
 235         default:
 236                 err = -EINVAL;
 237                 break;
 238         }
 239
 240         return err;
 241 }
 242
 243 static int w1_process_command_master(struct w1_master *dev,
 244         struct cn_msg *req_msg, struct w1_netlink_msg *req_hdr,
 245         struct w1_netlink_cmd *req_cmd)
 246 {
 247         int err = -EINVAL;
 248
 249         /* drop bus_mutex for search (does it's own locking), and add/remove
 250          * which doesn't use the bus
 251          */
 252         switch (req_cmd->cmd) {
 253         case W1_CMD_SEARCH:
 254         case W1_CMD_ALARM_SEARCH:
 255         case W1_CMD_LIST_SLAVES:
 256                 mutex_unlock(&dev->bus_mutex);
 257                 err = w1_get_slaves(dev, req_msg, req_hdr, req_cmd);
 258                 mutex_lock(&dev->bus_mutex);
 259                 break;
 260         case W1_CMD_READ:
 261         case W1_CMD_WRITE:
 262         case W1_CMD_TOUCH:
 263                 err = w1_process_command_io(dev, req_msg, req_hdr, req_cmd);
 264                 break;
 265         case W1_CMD_RESET:
 266                 err = w1_reset_bus(dev);
 267                 break;
 268         case W1_CMD_SLAVE_ADD:
 269         case W1_CMD_SLAVE_REMOVE:
 270                 mutex_unlock(&dev->bus_mutex);
 271                 mutex_lock(&dev->mutex);
 272                 err = w1_process_command_addremove(dev, req_msg, req_hdr,
 273                         req_cmd);
 274                 mutex_unlock(&dev->mutex);
 275                 mutex_lock(&dev->bus_mutex);
 276                 break;
 277         default:
 278                 err = -EINVAL;
 279                 break;
 280         }
 281
 282         return err;
 283 }
 284
 285 static int w1_process_command_slave(struct w1_slave *sl, struct cn_msg *msg,
 286                 struct w1_netlink_msg *hdr, struct w1_netlink_cmd *cmd)
 287 {
 288         dev_dbg(&sl->master->dev, "%s: %02x.%012llx.%02x: cmd=%02x, len=%u.\n",
 289                 __func__, sl->reg_num.family, (unsigned long long)sl->reg_num.id,
 290                 sl->reg_num.crc, cmd->cmd, cmd->len);
 291
 292         return w1_process_command_io(sl->master, msg, hdr, cmd);
 293 }
 294
 295 static int w1_process_command_root(struct cn_msg *msg,
 296         struct w1_netlink_msg *mcmd, u32 portid)
 297 {
 298         struct w1_master *m;
 299         struct cn_msg *cn;
 300         struct w1_netlink_msg *w;
 301         u32 *id;
 302
 303         cn = kmalloc(PAGE_SIZE, GFP_KERNEL);
 304         if (!cn)
 305                 return -ENOMEM;
 306
 307         cn->id.idx = CN_W1_IDX;
 308         cn->id.val = CN_W1_VAL;
 309
 310         cn->seq = msg->seq;
 311         cn->ack = 1;
 312         cn->len = sizeof(struct w1_netlink_msg);
 313         w = (struct w1_netlink_msg *)(cn + 1);
 314
 315         w->type = W1_LIST_MASTERS;
 316         w->status = 0;
 317         w->len = 0;
 318         id = (u32 *)(w + 1);
 319
 320         mutex_lock(&w1_mlock);
 321         list_for_each_entry(m, &w1_masters, w1_master_entry) {
 322                 if (cn->len + sizeof(*id) > PAGE_SIZE - sizeof(struct cn_msg)) {
 323                         cn_netlink_send(cn, portid, 0, GFP_KERNEL);
 324                         cn->ack++;
 325                         cn->len = sizeof(struct w1_netlink_msg);
 326                         w->len = 0;
 327                         id = (u32 *)(w + 1);
 328                 }
 329
 330                 *id = m->id;
 331                 w->len += sizeof(*id);
 332                 cn->len += sizeof(*id);
 333                 id++;
 334         }
 335         cn->ack = 0;
 336         cn_netlink_send(cn, portid, 0, GFP_KERNEL);
 337         mutex_unlock(&w1_mlock);
 338
 339         kfree(cn);
 340         return 0;
 341 }
 342
 343 static int w1_netlink_send_error(struct cn_msg *rcmsg, struct w1_netlink_msg *rmsg,
 344                 struct w1_netlink_cmd *rcmd, int portid, int error)
 345 {
 346         struct cn_msg *cmsg;
 347         struct w1_netlink_msg *msg;
 348         struct w1_netlink_cmd *cmd;
 349
 350         cmsg = kzalloc(sizeof(*msg) + sizeof(*cmd) + sizeof(*cmsg), GFP_KERNEL);
 351         if (!cmsg)
 352                 return -ENOMEM;
 353
 354         msg = (struct w1_netlink_msg *)(cmsg + 1);
 355         cmd = (struct w1_netlink_cmd *)(msg + 1);
 356
 357         memcpy(cmsg, rcmsg, sizeof(*cmsg));
 358         cmsg->len = sizeof(*msg);
 359
 360         memcpy(msg, rmsg, sizeof(*msg));
 361         msg->len = 0;
 362         msg->status = (short)-error;
 363
 364         if (rcmd) {
 365                 memcpy(cmd, rcmd, sizeof(*cmd));
 366                 cmd->len = 0;
 367                 msg->len += sizeof(*cmd);
 368                 cmsg->len += sizeof(*cmd);
 369         }
 370
 371         error = cn_netlink_send(cmsg, portid, 0, GFP_KERNEL);
 372         kfree(cmsg);
 373
 374         return error;
 375 }
 376
 377 /* Bundle together a reference count, the full message, and broken out
 378  * commands to be executed on each w1 master kthread in one memory allocation.
 379  */
 380 struct w1_cb_block {
 381         atomic_t refcnt;
 382         u32 portid; /* Sending process port ID */
 383         struct cn_msg msg;
 384         /* cn_msg data */
 385         /* one or more variable length struct w1_cb_node */
 386 };
 387 struct w1_cb_node {
 388         struct w1_async_cmd async;
 389         /* pointers within w1_cb_block and msg data */
 390         struct w1_cb_block *block;
 391         struct w1_netlink_msg *m;
 392         struct w1_slave *sl;
 393         struct w1_master *dev;
 394 };
 395
 396 static void w1_process_cb(struct w1_master *dev, struct w1_async_cmd *async_cmd)
 397 {
 398         struct w1_cb_node *node = container_of(async_cmd, struct w1_cb_node,
 399                 async);
 400         u16 mlen = node->m->len;
 401         u8 *cmd_data = node->m->data;
 402         int err = 0;
 403         struct w1_slave *sl = node->sl;
 404         struct w1_netlink_cmd *cmd = NULL;
 405
 406         mutex_lock(&dev->bus_mutex);
 407         dev->portid = node->block->portid;
 408         if (sl && w1_reset_select_slave(sl))
 409                 err = -ENODEV;
 410
 411         while (mlen && !err) {
 412                 cmd = (struct w1_netlink_cmd *)cmd_data;
 413
 414                 if (cmd->len + sizeof(struct w1_netlink_cmd) > mlen) {
 415                         err = -E2BIG;
 416                         break;
 417                 }
 418
 419                 if (sl)
 420                         err = w1_process_command_slave(sl, &node->block->msg,
 421                                 node->m, cmd);
 422                 else
 423                         err = w1_process_command_master(dev, &node->block->msg,
 424                                 node->m, cmd);
 425
 426                 w1_netlink_send_error(&node->block->msg, node->m, cmd,
 427                         node->block->portid, err);
 428                 err = 0;
 429
 430                 cmd_data += cmd->len + sizeof(struct w1_netlink_cmd);
 431                 mlen -= cmd->len + sizeof(struct w1_netlink_cmd);
 432         }
 433
 434         if (!cmd || err)
 435                 w1_netlink_send_error(&node->block->msg, node->m, cmd,
 436                         node->block->portid, err);
 437
 438         /* ref taken in w1_search_slave or w1_search_master_id when building
 439          * the block
 440          */
 441         if (sl)
 442                 w1_unref_slave(sl);
 443         else
 444                 atomic_dec(&dev->refcnt);
 445         dev->portid = 0;
 446         mutex_unlock(&dev->bus_mutex);
 447
 448         mutex_lock(&dev->list_mutex);
 449         list_del(&async_cmd->async_entry);
 450         mutex_unlock(&dev->list_mutex);
 451
 452         if (atomic_sub_return(1, &node->block->refcnt) == 0)
 453                 kfree(node->block);
 454 }
 455
 456 static void w1_cn_callback(struct cn_msg *msg, struct netlink_skb_parms *nsp)
 457 {
 458         struct w1_netlink_msg *m = (struct w1_netlink_msg *)(msg + 1);
 459         struct w1_slave *sl;
 460         struct w1_master *dev;
 461         u16 msg_len;
 462         int err = 0;
 463         struct w1_cb_block *block = NULL;
 464         struct w1_cb_node *node = NULL;
 465         int node_count = 0;
 466
 467         /* Count the number of master or slave commands there are to allocate
 468          * space for one cb_node each.
 469          */
 470         msg_len = msg->len;
 471         while (msg_len && !err) {
 472                 if (m->len + sizeof(struct w1_netlink_msg) > msg_len) {
 473                         err = -E2BIG;
 474                         break;
 475                 }
 476
 477                 if (m->type == W1_MASTER_CMD || m->type == W1_SLAVE_CMD)
 478                         ++node_count;
 479
 480                 msg_len -= sizeof(struct w1_netlink_msg) + m->len;
 481                 m = (struct w1_netlink_msg *)(((u8 *)m) +
 482                         sizeof(struct w1_netlink_msg) + m->len);
 483         }
 484         m = (struct w1_netlink_msg *)(msg + 1);
 485         if (node_count) {
 486                 /* msg->len doesn't include itself */
 487                 long size = sizeof(struct w1_cb_block) + msg->len +
 488                         node_count*sizeof(struct w1_cb_node);
 489                 block = kmalloc(size, GFP_KERNEL);
 490                 if (!block) {
 491                         w1_netlink_send_error(msg, m, NULL, nsp->portid,
 492                                 -ENOMEM);
 493                         return;
 494                 }
 495                 atomic_set(&block->refcnt, 1);
 496                 block->portid = nsp->portid;
 497                 memcpy(&block->msg, msg, sizeof(*msg) + msg->len);
 498                 node = (struct w1_cb_node *)((u8 *)block->msg.data + msg->len);
 499         }
 500
 501         msg_len = msg->len;
 502         while (msg_len && !err) {
 503
 504                 dev = NULL;
 505                 sl = NULL;
 506
 507                 if (m->len + sizeof(struct w1_netlink_msg) > msg_len) {
 508                         err = -E2BIG;
 509                         break;
 510                 }
 511
 512                 /* execute on this thread, no need to process later */
 513                 if (m->type == W1_LIST_MASTERS) {
 514                         err = w1_process_command_root(msg, m, nsp->portid);
 515                         goto out_cont;
 516                 }
 517
 518                 /* All following message types require additional data,
 519                  * check here before references are taken.
 520                  */
 521                 if (!m->len) {
 522                         err = -EPROTO;
 523                         goto out_cont;
 524                 }
 525
 526                 /* both search calls take reference counts */
 527                 if (m->type == W1_MASTER_CMD) {
 528                         dev = w1_search_master_id(m->id.mst.id);
 529                 } else if (m->type == W1_SLAVE_CMD) {
 530                         sl = w1_search_slave((struct w1_reg_num *)m->id.id);
 531                         if (sl)
 532                                 dev = sl->master;
 533                 } else {
 534                         printk(KERN_NOTICE
 535                                 "%s: msg: %x.%x, wrong type: %u, len: %u.\n",
 536                                 __func__, msg->id.idx, msg->id.val,
 537                                 m->type, m->len);
 538                         err = -EPROTO;
 539                         goto out_cont;
 540                 }
 541
 542                 if (!dev) {
 543                         err = -ENODEV;
 544                         goto out_cont;
 545                 }
 546
 547                 err = 0;
 548
 549                 atomic_inc(&block->refcnt);
 550                 node->async.cb = w1_process_cb;
 551                 node->block = block;
 552                 node->m = (struct w1_netlink_msg *)((u8 *)&block->msg +
 553                         (size_t)((u8 *)m - (u8 *)msg));
 554                 node->sl = sl;
 555                 node->dev = dev;
 556
 557                 mutex_lock(&dev->list_mutex);
 558                 list_add_tail(&node->async.async_entry, &dev->async_list);
 559                 wake_up_process(dev->thread);
 560                 mutex_unlock(&dev->list_mutex);
 561                 ++node;
 562
 563 out_cont:
 564                 if (err)
 565                         w1_netlink_send_error(msg, m, NULL, nsp->portid, err);
 566                 msg_len -= sizeof(struct w1_netlink_msg) + m->len;
 567                 m = (struct w1_netlink_msg *)(((u8 *)m) +
 568                         sizeof(struct w1_netlink_msg) + m->len);
 569
 570                 /*
 571                  * Let's allow requests for nonexisting devices.
 572                  */
 573                 if (err == -ENODEV)
 574                         err = 0;
 575         }
 576         if (block && atomic_sub_return(1, &block->refcnt) == 0)
 577                 kfree(block);
 578 }
 579
 580 int w1_init_netlink(void)
 581 {
 582         struct cb_id w1_id = {.idx = CN_W1_IDX, .val = CN_W1_VAL};
 583
 584         return cn_add_callback(&w1_id, "w1", &w1_cn_callback);
 585 }
 586
 587 void w1_fini_netlink(void)
 588 {
 589         struct cb_id w1_id = {.idx = CN_W1_IDX, .val = CN_W1_VAL};
 590
 591         cn_del_callback(&w1_id);
 592 }
 593 #else
 594 void w1_netlink_send(struct w1_master *dev, struct w1_netlink_msg *msg)
 595 {
 596 }
 597
 598 int w1_init_netlink(void)
 599 {
 600         return 0;
 601 }
 602
 603 void w1_fini_netlink(void)
 604 {
 605 }
 606 #endif