net/tipc/eth_media.c

   1 /*
   2  * net/tipc/eth_media.c: Ethernet bearer support for TIPC
   3  *
   4  * Copyright (c) 2001-2007, Ericsson AB
   5  * Copyright (c) 2005-2008, 2011, Wind River Systems
   6  * All rights reserved.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions are met:
  10  *
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  * 3. Neither the names of the copyright holders nor the names of its
  17  *    contributors may be used to endorse or promote products derived from
  18  *    this software without specific prior written permission.
  19  *
  20  * Alternatively, this software may be distributed under the terms of the
  21  * GNU General Public License ("GPL") version 2 as published by the Free
  22  * Software Foundation.
  23  *
  24  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  25  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  27  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
  28  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  29  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  30  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  31  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  32  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  33  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  34  * POSSIBILITY OF SUCH DAMAGE.
  35  */
  36
  37 #include "core.h"
  38 #include "bearer.h"
  39
  40 #define MAX_ETH_BEARERS         MAX_BEARERS
  41
  42 #define ETH_ADDR_OFFSET 4       /* message header offset of MAC address */
  43
  44 /**
  45  * struct eth_bearer - Ethernet bearer data structure
  46  * @bearer: ptr to associated "generic" bearer structure
  47  * @dev: ptr to associated Ethernet network device
  48  * @tipc_packet_type: used in binding TIPC to Ethernet driver
  49  * @cleanup: work item used when disabling bearer
  50  */
  51
  52 struct eth_bearer {
  53         struct tipc_bearer *bearer;
  54         struct net_device *dev;
  55         struct packet_type tipc_packet_type;
  56         struct work_struct cleanup;
  57 };
  58
  59 static struct tipc_media eth_media_info;
  60 static struct eth_bearer eth_bearers[MAX_ETH_BEARERS];
  61 static int eth_started;
  62 static struct notifier_block notifier;
  63
  64 /**
  65  * eth_media_addr_set - initialize Ethernet media address structure
  66  *
  67  * Media-dependent "value" field stores MAC address in first 6 bytes
  68  * and zeroes out the remaining bytes.
  69  */
  70
  71 static void eth_media_addr_set(struct tipc_media_addr *a, char *mac)
  72 {
  73         memcpy(a->value, mac, ETH_ALEN);
  74         memset(a->value + ETH_ALEN, 0, sizeof(a->value) - ETH_ALEN);
  75         a->media_id = TIPC_MEDIA_TYPE_ETH;
  76         a->broadcast = !memcmp(mac, eth_media_info.bcast_addr.value, ETH_ALEN);
  77 }
  78
  79 /**
  80  * send_msg - send a TIPC message out over an Ethernet interface
  81  */
  82
  83 static int send_msg(struct sk_buff *buf, struct tipc_bearer *tb_ptr,
  84                     struct tipc_media_addr *dest)
  85 {
  86         struct sk_buff *clone;
  87         struct net_device *dev;
  88         int delta;
  89
  90         clone = skb_clone(buf, GFP_ATOMIC);
  91         if (!clone)
  92                 return 0;
  93
  94         dev = ((struct eth_bearer *)(tb_ptr->usr_handle))->dev;
  95         delta = dev->hard_header_len - skb_headroom(buf);
  96
  97         if ((delta > 0) &&
  98             pskb_expand_head(clone, SKB_DATA_ALIGN(delta), 0, GFP_ATOMIC)) {
  99                 kfree_skb(clone);
 100                 return 0;
 101         }
 102
 103         skb_reset_network_header(clone);
 104         clone->dev = dev;
 105         dev_hard_header(clone, dev, ETH_P_TIPC, dest->value,
 106                         dev->dev_addr, clone->len);
 107         dev_queue_xmit(clone);
 108         return 0;
 109 }
 110
 111 /**
 112  * recv_msg - handle incoming TIPC message from an Ethernet interface
 113  *
 114  * Accept only packets explicitly sent to this node, or broadcast packets;
 115  * ignores packets sent using Ethernet multicast, and traffic sent to other
 116  * nodes (which can happen if interface is running in promiscuous mode).
 117  */
 118
 119 static int recv_msg(struct sk_buff *buf, struct net_device *dev,
 120                     struct packet_type *pt, struct net_device *orig_dev)
 121 {
 122         struct eth_bearer *eb_ptr = (struct eth_bearer *)pt->af_packet_priv;
 123
 124         if (!net_eq(dev_net(dev), &init_net)) {
 125                 kfree_skb(buf);
 126                 return 0;
 127         }
 128
 129         if (likely(eb_ptr->bearer)) {
 130                 if (likely(buf->pkt_type <= PACKET_BROADCAST)) {
 131                         buf->next = NULL;
 132                         tipc_recv_msg(buf, eb_ptr->bearer);
 133                         return 0;
 134                 }
 135         }
 136         kfree_skb(buf);
 137         return 0;
 138 }
 139
 140 /**
 141  * enable_bearer - attach TIPC bearer to an Ethernet interface
 142  */
 143
 144 static int enable_bearer(struct tipc_bearer *tb_ptr)
 145 {
 146         struct net_device *dev = NULL;
 147         struct net_device *pdev = NULL;
 148         struct eth_bearer *eb_ptr = &eth_bearers[0];
 149         struct eth_bearer *stop = &eth_bearers[MAX_ETH_BEARERS];
 150         char *driver_name = strchr((const char *)tb_ptr->name, ':') + 1;
 151         int pending_dev = 0;
 152
 153         /* Find unused Ethernet bearer structure */
 154
 155         while (eb_ptr->dev) {
 156                 if (!eb_ptr->bearer)
 157                         pending_dev++;
 158                 if (++eb_ptr == stop)
 159                         return pending_dev ? -EAGAIN : -EDQUOT;
 160         }
 161
 162         /* Find device with specified name */
 163
 164         read_lock(&dev_base_lock);
 165         for_each_netdev(&init_net, pdev) {
 166                 if (!strncmp(pdev->name, driver_name, IFNAMSIZ)) {
 167                         dev = pdev;
 168                         dev_hold(dev);
 169                         break;
 170                 }
 171         }
 172         read_unlock(&dev_base_lock);
 173         if (!dev)
 174                 return -ENODEV;
 175
 176         /* Create Ethernet bearer for device */
 177
 178         eb_ptr->dev = dev;
 179         eb_ptr->tipc_packet_type.type = htons(ETH_P_TIPC);
 180         eb_ptr->tipc_packet_type.dev = dev;
 181         eb_ptr->tipc_packet_type.func = recv_msg;
 182         eb_ptr->tipc_packet_type.af_packet_priv = eb_ptr;
 183         INIT_LIST_HEAD(&(eb_ptr->tipc_packet_type.list));
 184         dev_add_pack(&eb_ptr->tipc_packet_type);
 185
 186         /* Associate TIPC bearer with Ethernet bearer */
 187
 188         eb_ptr->bearer = tb_ptr;
 189         tb_ptr->usr_handle = (void *)eb_ptr;
 190         tb_ptr->mtu = dev->mtu;
 191         tb_ptr->blocked = 0;
 192         eth_media_addr_set(&tb_ptr->addr, (char *)dev->dev_addr);
 193         return 0;
 194 }
 195
 196 /**
 197  * cleanup_bearer - break association between Ethernet bearer and interface
 198  *
 199  * This routine must be invoked from a work queue because it can sleep.
 200  */
 201
 202 static void cleanup_bearer(struct work_struct *work)
 203 {
 204         struct eth_bearer *eb_ptr =
 205                 container_of(work, struct eth_bearer, cleanup);
 206
 207         dev_remove_pack(&eb_ptr->tipc_packet_type);
 208         dev_put(eb_ptr->dev);
 209         eb_ptr->dev = NULL;
 210 }
 211
 212 /**
 213  * disable_bearer - detach TIPC bearer from an Ethernet interface
 214  *
 215  * Mark Ethernet bearer as inactive so that incoming buffers are thrown away,
 216  * then get worker thread to complete bearer cleanup.  (Can't do cleanup
 217  * here because cleanup code needs to sleep and caller holds spinlocks.)
 218  */
 219
 220 static void disable_bearer(struct tipc_bearer *tb_ptr)
 221 {
 222         struct eth_bearer *eb_ptr = (struct eth_bearer *)tb_ptr->usr_handle;
 223
 224         eb_ptr->bearer = NULL;
 225         INIT_WORK(&eb_ptr->cleanup, cleanup_bearer);
 226         schedule_work(&eb_ptr->cleanup);
 227 }
 228
 229 /**
 230  * recv_notification - handle device updates from OS
 231  *
 232  * Change the state of the Ethernet bearer (if any) associated with the
 233  * specified device.
 234  */
 235
 236 static int recv_notification(struct notifier_block *nb, unsigned long evt,
 237                              void *dv)
 238 {
 239         struct net_device *dev = (struct net_device *)dv;
 240         struct eth_bearer *eb_ptr = &eth_bearers[0];
 241         struct eth_bearer *stop = &eth_bearers[MAX_ETH_BEARERS];
 242
 243         if (!net_eq(dev_net(dev), &init_net))
 244                 return NOTIFY_DONE;
 245
 246         while ((eb_ptr->dev != dev)) {
 247                 if (++eb_ptr == stop)
 248                         return NOTIFY_DONE;     /* couldn't find device */
 249         }
 250         if (!eb_ptr->bearer)
 251                 return NOTIFY_DONE;             /* bearer had been disabled */
 252
 253         eb_ptr->bearer->mtu = dev->mtu;
 254
 255         switch (evt) {
 256         case NETDEV_CHANGE:
 257                 if (netif_carrier_ok(dev))
 258                         tipc_continue(eb_ptr->bearer);
 259                 else
 260                         tipc_block_bearer(eb_ptr->bearer->name);
 261                 break;
 262         case NETDEV_UP:
 263                 tipc_continue(eb_ptr->bearer);
 264                 break;
 265         case NETDEV_DOWN:
 266                 tipc_block_bearer(eb_ptr->bearer->name);
 267                 break;
 268         case NETDEV_CHANGEMTU:
 269         case NETDEV_CHANGEADDR:
 270                 tipc_block_bearer(eb_ptr->bearer->name);
 271                 tipc_continue(eb_ptr->bearer);
 272                 break;
 273         case NETDEV_UNREGISTER:
 274         case NETDEV_CHANGENAME:
 275                 tipc_disable_bearer(eb_ptr->bearer->name);
 276                 break;
 277         }
 278         return NOTIFY_OK;
 279 }
 280
 281 /**
 282  * eth_addr2str - convert Ethernet address to string
 283  */
 284
 285 static int eth_addr2str(struct tipc_media_addr *a, char *str_buf, int str_size)
 286 {
 287         if (str_size < 18)      /* 18 = strlen("aa:bb:cc:dd:ee:ff\0") */
 288                 return 1;
 289
 290         sprintf(str_buf, "%pM", a->value);
 291         return 0;
 292 }
 293
 294 /**
 295  * eth_str2addr - convert string to Ethernet address
 296  */
 297
 298 static int eth_str2addr(struct tipc_media_addr *a, char *str_buf)
 299 {
 300         char mac[ETH_ALEN];
 301         int r;
 302
 303         r = sscanf(str_buf, "%02x:%02x:%02x:%02x:%02x:%02x",
 304                        (u32 *)&mac[0], (u32 *)&mac[1], (u32 *)&mac[2],
 305                        (u32 *)&mac[3], (u32 *)&mac[4], (u32 *)&mac[5]);
 306
 307         if (r != ETH_ALEN)
 308                 return 1;
 309
 310         eth_media_addr_set(a, mac);
 311         return 0;
 312 }
 313
 314 /**
 315  * eth_str2addr - convert Ethernet address format to message header format
 316  */
 317
 318 static int eth_addr2msg(struct tipc_media_addr *a, char *msg_area)
 319 {
 320         memset(msg_area, 0, TIPC_MEDIA_ADDR_SIZE);
 321         msg_area[TIPC_MEDIA_TYPE_OFFSET] = TIPC_MEDIA_TYPE_ETH;
 322         memcpy(msg_area + ETH_ADDR_OFFSET, a->value, ETH_ALEN);
 323         return 0;
 324 }
 325
 326 /**
 327  * eth_str2addr - convert message header address format to Ethernet format
 328  */
 329
 330 static int eth_msg2addr(struct tipc_media_addr *a, char *msg_area)
 331 {
 332         if (msg_area[TIPC_MEDIA_TYPE_OFFSET] != TIPC_MEDIA_TYPE_ETH)
 333                 return 1;
 334
 335         eth_media_addr_set(a, msg_area + ETH_ADDR_OFFSET);
 336         return 0;
 337 }
 338
 339 /*
 340  * Ethernet media registration info
 341  */
 342
 343 static struct tipc_media eth_media_info = {
 344         .send_msg       = send_msg,
 345         .enable_bearer  = enable_bearer,
 346         .disable_bearer = disable_bearer,
 347         .addr2str       = eth_addr2str,
 348         .str2addr       = eth_str2addr,
 349         .addr2msg       = eth_addr2msg,
 350         .msg2addr       = eth_msg2addr,
 351         .bcast_addr     = { { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff },
 352                             TIPC_MEDIA_TYPE_ETH, 1 },
 353         .priority       = TIPC_DEF_LINK_PRI,
 354         .tolerance      = TIPC_DEF_LINK_TOL,
 355         .window         = TIPC_DEF_LINK_WIN,
 356         .type_id        = TIPC_MEDIA_TYPE_ETH,
 357         .name           = "eth"
 358 };
 359
 360 /**
 361  * tipc_eth_media_start - activate Ethernet bearer support
 362  *
 363  * Register Ethernet media type with TIPC bearer code.  Also register
 364  * with OS for notifications about device state changes.
 365  */
 366
 367 int tipc_eth_media_start(void)
 368 {
 369         int res;
 370
 371         if (eth_started)
 372                 return -EINVAL;
 373
 374         res = tipc_register_media(&eth_media_info);
 375         if (res)
 376                 return res;
 377
 378         notifier.notifier_call = &recv_notification;
 379         notifier.priority = 0;
 380         res = register_netdevice_notifier(&notifier);
 381         if (!res)
 382                 eth_started = 1;
 383         return res;
 384 }
 385
 386 /**
 387  * tipc_eth_media_stop - deactivate Ethernet bearer support
 388  */
 389
 390 void tipc_eth_media_stop(void)
 391 {
 392         if (!eth_started)
 393                 return;
 394
 395         flush_scheduled_work();
 396         unregister_netdevice_notifier(&notifier);
 397         eth_started = 0;
 398 }