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  * @setup: work item used when enabling bearer
  50  * @cleanup: work item used when disabling bearer
  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 setup;
  57         struct work_struct cleanup;
  58 };
  59
  60 static struct tipc_media eth_media_info;
  61 static struct eth_bearer eth_bearers[MAX_ETH_BEARERS];
  62 static int eth_started;
  63
  64 static int recv_notification(struct notifier_block *nb, unsigned long evt,
  65                               void *dv);
  66 /*
  67  * Network device notifier info
  68  */
  69 static struct notifier_block notifier = {
  70         .notifier_call  = recv_notification,
  71         .priority       = 0
  72 };
  73
  74 /**
  75  * eth_media_addr_set - initialize Ethernet media address structure
  76  *
  77  * Media-dependent "value" field stores MAC address in first 6 bytes
  78  * and zeroes out the remaining bytes.
  79  */
  80 static void eth_media_addr_set(struct tipc_media_addr *a, char *mac)
  81 {
  82         memcpy(a->value, mac, ETH_ALEN);
  83         memset(a->value + ETH_ALEN, 0, sizeof(a->value) - ETH_ALEN);
  84         a->media_id = TIPC_MEDIA_TYPE_ETH;
  85         a->broadcast = !memcmp(mac, eth_media_info.bcast_addr.value, ETH_ALEN);
  86 }
  87
  88 /**
  89  * send_msg - send a TIPC message out over an Ethernet interface
  90  */
  91 static int send_msg(struct sk_buff *buf, struct tipc_bearer *tb_ptr,
  92                     struct tipc_media_addr *dest)
  93 {
  94         struct sk_buff *clone;
  95         struct net_device *dev;
  96         int delta;
  97
  98         clone = skb_clone(buf, GFP_ATOMIC);
  99         if (!clone)
 100                 return 0;
 101
 102         dev = ((struct eth_bearer *)(tb_ptr->usr_handle))->dev;
 103         delta = dev->hard_header_len - skb_headroom(buf);
 104
 105         if ((delta > 0) &&
 106             pskb_expand_head(clone, SKB_DATA_ALIGN(delta), 0, GFP_ATOMIC)) {
 107                 kfree_skb(clone);
 108                 return 0;
 109         }
 110
 111         skb_reset_network_header(clone);
 112         clone->dev = dev;
 113         dev_hard_header(clone, dev, ETH_P_TIPC, dest->value,
 114                         dev->dev_addr, clone->len);
 115         dev_queue_xmit(clone);
 116         return 0;
 117 }
 118
 119 /**
 120  * recv_msg - handle incoming TIPC message from an Ethernet interface
 121  *
 122  * Accept only packets explicitly sent to this node, or broadcast packets;
 123  * ignores packets sent using Ethernet multicast, and traffic sent to other
 124  * nodes (which can happen if interface is running in promiscuous mode).
 125  */
 126 static int recv_msg(struct sk_buff *buf, struct net_device *dev,
 127                     struct packet_type *pt, struct net_device *orig_dev)
 128 {
 129         struct eth_bearer *eb_ptr = (struct eth_bearer *)pt->af_packet_priv;
 130
 131         if (!net_eq(dev_net(dev), &init_net)) {
 132                 kfree_skb(buf);
 133                 return 0;
 134         }
 135
 136         if (likely(eb_ptr->bearer)) {
 137                 if (likely(buf->pkt_type <= PACKET_BROADCAST)) {
 138                         buf->next = NULL;
 139                         tipc_recv_msg(buf, eb_ptr->bearer);
 140                         return 0;
 141                 }
 142         }
 143         kfree_skb(buf);
 144         return 0;
 145 }
 146
 147 /**
 148  * setup_bearer - setup association between Ethernet bearer and interface
 149  */
 150 static void setup_bearer(struct work_struct *work)
 151 {
 152         struct eth_bearer *eb_ptr =
 153                 container_of(work, struct eth_bearer, setup);
 154
 155         dev_add_pack(&eb_ptr->tipc_packet_type);
 156 }
 157
 158 /**
 159  * enable_bearer - attach TIPC bearer to an Ethernet interface
 160  */
 161 static int enable_bearer(struct tipc_bearer *tb_ptr)
 162 {
 163         struct net_device *dev = NULL;
 164         struct net_device *pdev = NULL;
 165         struct eth_bearer *eb_ptr = &eth_bearers[0];
 166         struct eth_bearer *stop = &eth_bearers[MAX_ETH_BEARERS];
 167         char *driver_name = strchr((const char *)tb_ptr->name, ':') + 1;
 168         int pending_dev = 0;
 169
 170         /* Find unused Ethernet bearer structure */
 171         while (eb_ptr->dev) {
 172                 if (!eb_ptr->bearer)
 173                         pending_dev++;
 174                 if (++eb_ptr == stop)
 175                         return pending_dev ? -EAGAIN : -EDQUOT;
 176         }
 177
 178         /* Find device with specified name */
 179         read_lock(&dev_base_lock);
 180         for_each_netdev(&init_net, pdev) {
 181                 if (!strncmp(pdev->name, driver_name, IFNAMSIZ)) {
 182                         dev = pdev;
 183                         dev_hold(dev);
 184                         break;
 185                 }
 186         }
 187         read_unlock(&dev_base_lock);
 188         if (!dev)
 189                 return -ENODEV;
 190
 191         /* Create Ethernet bearer for device */
 192         eb_ptr->dev = dev;
 193         eb_ptr->tipc_packet_type.type = htons(ETH_P_TIPC);
 194         eb_ptr->tipc_packet_type.dev = dev;
 195         eb_ptr->tipc_packet_type.func = recv_msg;
 196         eb_ptr->tipc_packet_type.af_packet_priv = eb_ptr;
 197         INIT_LIST_HEAD(&(eb_ptr->tipc_packet_type.list));
 198         INIT_WORK(&eb_ptr->setup, setup_bearer);
 199         schedule_work(&eb_ptr->setup);
 200
 201         /* Associate TIPC bearer with Ethernet bearer */
 202         eb_ptr->bearer = tb_ptr;
 203         tb_ptr->usr_handle = (void *)eb_ptr;
 204         tb_ptr->mtu = dev->mtu;
 205         tb_ptr->blocked = 0;
 206         eth_media_addr_set(&tb_ptr->addr, (char *)dev->dev_addr);
 207         return 0;
 208 }
 209
 210 /**
 211  * cleanup_bearer - break association between Ethernet bearer and interface
 212  *
 213  * This routine must be invoked from a work queue because it can sleep.
 214  */
 215 static void cleanup_bearer(struct work_struct *work)
 216 {
 217         struct eth_bearer *eb_ptr =
 218                 container_of(work, struct eth_bearer, cleanup);
 219
 220         dev_remove_pack(&eb_ptr->tipc_packet_type);
 221         dev_put(eb_ptr->dev);
 222         eb_ptr->dev = NULL;
 223 }
 224
 225 /**
 226  * disable_bearer - detach TIPC bearer from an Ethernet interface
 227  *
 228  * Mark Ethernet bearer as inactive so that incoming buffers are thrown away,
 229  * then get worker thread to complete bearer cleanup.  (Can't do cleanup
 230  * here because cleanup code needs to sleep and caller holds spinlocks.)
 231  */
 232 static void disable_bearer(struct tipc_bearer *tb_ptr)
 233 {
 234         struct eth_bearer *eb_ptr = (struct eth_bearer *)tb_ptr->usr_handle;
 235
 236         eb_ptr->bearer = NULL;
 237         INIT_WORK(&eb_ptr->cleanup, cleanup_bearer);
 238         schedule_work(&eb_ptr->cleanup);
 239 }
 240
 241 /**
 242  * recv_notification - handle device updates from OS
 243  *
 244  * Change the state of the Ethernet bearer (if any) associated with the
 245  * specified device.
 246  */
 247 static int recv_notification(struct notifier_block *nb, unsigned long evt,
 248                              void *dv)
 249 {
 250         struct net_device *dev = (struct net_device *)dv;
 251         struct eth_bearer *eb_ptr = &eth_bearers[0];
 252         struct eth_bearer *stop = &eth_bearers[MAX_ETH_BEARERS];
 253
 254         if (!net_eq(dev_net(dev), &init_net))
 255                 return NOTIFY_DONE;
 256
 257         while ((eb_ptr->dev != dev)) {
 258                 if (++eb_ptr == stop)
 259                         return NOTIFY_DONE;     /* couldn't find device */
 260         }
 261         if (!eb_ptr->bearer)
 262                 return NOTIFY_DONE;             /* bearer had been disabled */
 263
 264         eb_ptr->bearer->mtu = dev->mtu;
 265
 266         switch (evt) {
 267         case NETDEV_CHANGE:
 268                 if (netif_carrier_ok(dev))
 269                         tipc_continue(eb_ptr->bearer);
 270                 else
 271                         tipc_block_bearer(eb_ptr->bearer->name);
 272                 break;
 273         case NETDEV_UP:
 274                 tipc_continue(eb_ptr->bearer);
 275                 break;
 276         case NETDEV_DOWN:
 277                 tipc_block_bearer(eb_ptr->bearer->name);
 278                 break;
 279         case NETDEV_CHANGEMTU:
 280         case NETDEV_CHANGEADDR:
 281                 tipc_block_bearer(eb_ptr->bearer->name);
 282                 tipc_continue(eb_ptr->bearer);
 283                 break;
 284         case NETDEV_UNREGISTER:
 285         case NETDEV_CHANGENAME:
 286                 tipc_disable_bearer(eb_ptr->bearer->name);
 287                 break;
 288         }
 289         return NOTIFY_OK;
 290 }
 291
 292 /**
 293  * eth_addr2str - convert Ethernet address to string
 294  */
 295 static int eth_addr2str(struct tipc_media_addr *a, char *str_buf, int str_size)
 296 {
 297         if (str_size < 18)      /* 18 = strlen("aa:bb:cc:dd:ee:ff\0") */
 298                 return 1;
 299
 300         sprintf(str_buf, "%pM", a->value);
 301         return 0;
 302 }
 303
 304 /**
 305  * eth_str2addr - convert string to Ethernet address
 306  */
 307 static int eth_str2addr(struct tipc_media_addr *a, char *str_buf)
 308 {
 309         char mac[ETH_ALEN];
 310         int r;
 311
 312         r = sscanf(str_buf, "%02x:%02x:%02x:%02x:%02x:%02x",
 313                        (u32 *)&mac[0], (u32 *)&mac[1], (u32 *)&mac[2],
 314                        (u32 *)&mac[3], (u32 *)&mac[4], (u32 *)&mac[5]);
 315
 316         if (r != ETH_ALEN)
 317                 return 1;
 318
 319         eth_media_addr_set(a, mac);
 320         return 0;
 321 }
 322
 323 /**
 324  * eth_str2addr - convert Ethernet address format to message header format
 325  */
 326 static int eth_addr2msg(struct tipc_media_addr *a, char *msg_area)
 327 {
 328         memset(msg_area, 0, TIPC_MEDIA_ADDR_SIZE);
 329         msg_area[TIPC_MEDIA_TYPE_OFFSET] = TIPC_MEDIA_TYPE_ETH;
 330         memcpy(msg_area + ETH_ADDR_OFFSET, a->value, ETH_ALEN);
 331         return 0;
 332 }
 333
 334 /**
 335  * eth_str2addr - convert message header address format to Ethernet format
 336  */
 337 static int eth_msg2addr(struct tipc_media_addr *a, char *msg_area)
 338 {
 339         if (msg_area[TIPC_MEDIA_TYPE_OFFSET] != TIPC_MEDIA_TYPE_ETH)
 340                 return 1;
 341
 342         eth_media_addr_set(a, msg_area + ETH_ADDR_OFFSET);
 343         return 0;
 344 }
 345
 346 /*
 347  * Ethernet media registration info
 348  */
 349 static struct tipc_media eth_media_info = {
 350         .send_msg       = send_msg,
 351         .enable_bearer  = enable_bearer,
 352         .disable_bearer = disable_bearer,
 353         .addr2str       = eth_addr2str,
 354         .str2addr       = eth_str2addr,
 355         .addr2msg       = eth_addr2msg,
 356         .msg2addr       = eth_msg2addr,
 357         .bcast_addr     = { { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff },
 358                             TIPC_MEDIA_TYPE_ETH, 1 },
 359         .priority       = TIPC_DEF_LINK_PRI,
 360         .tolerance      = TIPC_DEF_LINK_TOL,
 361         .window         = TIPC_DEF_LINK_WIN,
 362         .type_id        = TIPC_MEDIA_TYPE_ETH,
 363         .name           = "eth"
 364 };
 365
 366 /**
 367  * tipc_eth_media_start - activate Ethernet bearer support
 368  *
 369  * Register Ethernet media type with TIPC bearer code.  Also register
 370  * with OS for notifications about device state changes.
 371  */
 372 int tipc_eth_media_start(void)
 373 {
 374         int res;
 375
 376         if (eth_started)
 377                 return -EINVAL;
 378
 379         res = tipc_register_media(&eth_media_info);
 380         if (res)
 381                 return res;
 382
 383         res = register_netdevice_notifier(&notifier);
 384         if (!res)
 385                 eth_started = 1;
 386         return res;
 387 }
 388
 389 /**
 390  * tipc_eth_media_stop - deactivate Ethernet bearer support
 391  */
 392 void tipc_eth_media_stop(void)
 393 {
 394         if (!eth_started)
 395                 return;
 396
 397         flush_scheduled_work();
 398         unregister_netdevice_notifier(&notifier);
 399         eth_started = 0;
 400 }