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 struct eth_bearer {
  52         struct tipc_bearer *bearer;
  53         struct net_device *dev;
  54         struct packet_type tipc_packet_type;
  55         struct work_struct cleanup;
  56 };
  57
  58 static struct tipc_media eth_media_info;
  59 static struct eth_bearer eth_bearers[MAX_ETH_BEARERS];
  60 static int eth_started;
  61 static struct notifier_block notifier;
  62
  63 /**
  64  * eth_media_addr_set - initialize Ethernet media address structure
  65  *
  66  * Media-dependent "value" field stores MAC address in first 6 bytes
  67  * and zeroes out the remaining bytes.
  68  */
  69 static void eth_media_addr_set(struct tipc_media_addr *a, char *mac)
  70 {
  71         memcpy(a->value, mac, ETH_ALEN);
  72         memset(a->value + ETH_ALEN, 0, sizeof(a->value) - ETH_ALEN);
  73         a->media_id = TIPC_MEDIA_TYPE_ETH;
  74         a->broadcast = !memcmp(mac, eth_media_info.bcast_addr.value, ETH_ALEN);
  75 }
  76
  77 /**
  78  * send_msg - send a TIPC message out over an Ethernet interface
  79  */
  80 static int send_msg(struct sk_buff *buf, struct tipc_bearer *tb_ptr,
  81                     struct tipc_media_addr *dest)
  82 {
  83         struct sk_buff *clone;
  84         struct net_device *dev;
  85         int delta;
  86
  87         clone = skb_clone(buf, GFP_ATOMIC);
  88         if (!clone)
  89                 return 0;
  90
  91         dev = ((struct eth_bearer *)(tb_ptr->usr_handle))->dev;
  92         delta = dev->hard_header_len - skb_headroom(buf);
  93
  94         if ((delta > 0) &&
  95             pskb_expand_head(clone, SKB_DATA_ALIGN(delta), 0, GFP_ATOMIC)) {
  96                 kfree_skb(clone);
  97                 return 0;
  98         }
  99
 100         skb_reset_network_header(clone);
 101         clone->dev = dev;
 102         dev_hard_header(clone, dev, ETH_P_TIPC, dest->value,
 103                         dev->dev_addr, clone->len);
 104         dev_queue_xmit(clone);
 105         return 0;
 106 }
 107
 108 /**
 109  * recv_msg - handle incoming TIPC message from an Ethernet interface
 110  *
 111  * Accept only packets explicitly sent to this node, or broadcast packets;
 112  * ignores packets sent using Ethernet multicast, and traffic sent to other
 113  * nodes (which can happen if interface is running in promiscuous mode).
 114  */
 115 static int recv_msg(struct sk_buff *buf, struct net_device *dev,
 116                     struct packet_type *pt, struct net_device *orig_dev)
 117 {
 118         struct eth_bearer *eb_ptr = (struct eth_bearer *)pt->af_packet_priv;
 119
 120         if (!net_eq(dev_net(dev), &init_net)) {
 121                 kfree_skb(buf);
 122                 return 0;
 123         }
 124
 125         if (likely(eb_ptr->bearer)) {
 126                 if (likely(buf->pkt_type <= PACKET_BROADCAST)) {
 127                         buf->next = NULL;
 128                         tipc_recv_msg(buf, eb_ptr->bearer);
 129                         return 0;
 130                 }
 131         }
 132         kfree_skb(buf);
 133         return 0;
 134 }
 135
 136 /**
 137  * enable_bearer - attach TIPC bearer to an Ethernet interface
 138  */
 139 static int enable_bearer(struct tipc_bearer *tb_ptr)
 140 {
 141         struct net_device *dev = NULL;
 142         struct net_device *pdev = NULL;
 143         struct eth_bearer *eb_ptr = &eth_bearers[0];
 144         struct eth_bearer *stop = &eth_bearers[MAX_ETH_BEARERS];
 145         char *driver_name = strchr((const char *)tb_ptr->name, ':') + 1;
 146         int pending_dev = 0;
 147
 148         /* Find unused Ethernet bearer structure */
 149         while (eb_ptr->dev) {
 150                 if (!eb_ptr->bearer)
 151                         pending_dev++;
 152                 if (++eb_ptr == stop)
 153                         return pending_dev ? -EAGAIN : -EDQUOT;
 154         }
 155
 156         /* Find device with specified name */
 157         read_lock(&dev_base_lock);
 158         for_each_netdev(&init_net, pdev) {
 159                 if (!strncmp(pdev->name, driver_name, IFNAMSIZ)) {
 160                         dev = pdev;
 161                         dev_hold(dev);
 162                         break;
 163                 }
 164         }
 165         read_unlock(&dev_base_lock);
 166         if (!dev)
 167                 return -ENODEV;
 168
 169         /* Create Ethernet bearer for device */
 170         eb_ptr->dev = dev;
 171         eb_ptr->tipc_packet_type.type = htons(ETH_P_TIPC);
 172         eb_ptr->tipc_packet_type.dev = dev;
 173         eb_ptr->tipc_packet_type.func = recv_msg;
 174         eb_ptr->tipc_packet_type.af_packet_priv = eb_ptr;
 175         INIT_LIST_HEAD(&(eb_ptr->tipc_packet_type.list));
 176         dev_add_pack(&eb_ptr->tipc_packet_type);
 177
 178         /* Associate TIPC bearer with Ethernet bearer */
 179         eb_ptr->bearer = tb_ptr;
 180         tb_ptr->usr_handle = (void *)eb_ptr;
 181         tb_ptr->mtu = dev->mtu;
 182         tb_ptr->blocked = 0;
 183         eth_media_addr_set(&tb_ptr->addr, (char *)dev->dev_addr);
 184         return 0;
 185 }
 186
 187 /**
 188  * cleanup_bearer - break association between Ethernet bearer and interface
 189  *
 190  * This routine must be invoked from a work queue because it can sleep.
 191  */
 192 static void cleanup_bearer(struct work_struct *work)
 193 {
 194         struct eth_bearer *eb_ptr =
 195                 container_of(work, struct eth_bearer, cleanup);
 196
 197         dev_remove_pack(&eb_ptr->tipc_packet_type);
 198         dev_put(eb_ptr->dev);
 199         eb_ptr->dev = NULL;
 200 }
 201
 202 /**
 203  * disable_bearer - detach TIPC bearer from an Ethernet interface
 204  *
 205  * Mark Ethernet bearer as inactive so that incoming buffers are thrown away,
 206  * then get worker thread to complete bearer cleanup.  (Can't do cleanup
 207  * here because cleanup code needs to sleep and caller holds spinlocks.)
 208  */
 209 static void disable_bearer(struct tipc_bearer *tb_ptr)
 210 {
 211         struct eth_bearer *eb_ptr = (struct eth_bearer *)tb_ptr->usr_handle;
 212
 213         eb_ptr->bearer = NULL;
 214         INIT_WORK(&eb_ptr->cleanup, cleanup_bearer);
 215         schedule_work(&eb_ptr->cleanup);
 216 }
 217
 218 /**
 219  * recv_notification - handle device updates from OS
 220  *
 221  * Change the state of the Ethernet bearer (if any) associated with the
 222  * specified device.
 223  */
 224 static int recv_notification(struct notifier_block *nb, unsigned long evt,
 225                              void *dv)
 226 {
 227         struct net_device *dev = (struct net_device *)dv;
 228         struct eth_bearer *eb_ptr = &eth_bearers[0];
 229         struct eth_bearer *stop = &eth_bearers[MAX_ETH_BEARERS];
 230
 231         if (!net_eq(dev_net(dev), &init_net))
 232                 return NOTIFY_DONE;
 233
 234         while ((eb_ptr->dev != dev)) {
 235                 if (++eb_ptr == stop)
 236                         return NOTIFY_DONE;     /* couldn't find device */
 237         }
 238         if (!eb_ptr->bearer)
 239                 return NOTIFY_DONE;             /* bearer had been disabled */
 240
 241         eb_ptr->bearer->mtu = dev->mtu;
 242
 243         switch (evt) {
 244         case NETDEV_CHANGE:
 245                 if (netif_carrier_ok(dev))
 246                         tipc_continue(eb_ptr->bearer);
 247                 else
 248                         tipc_block_bearer(eb_ptr->bearer->name);
 249                 break;
 250         case NETDEV_UP:
 251                 tipc_continue(eb_ptr->bearer);
 252                 break;
 253         case NETDEV_DOWN:
 254                 tipc_block_bearer(eb_ptr->bearer->name);
 255                 break;
 256         case NETDEV_CHANGEMTU:
 257         case NETDEV_CHANGEADDR:
 258                 tipc_block_bearer(eb_ptr->bearer->name);
 259                 tipc_continue(eb_ptr->bearer);
 260                 break;
 261         case NETDEV_UNREGISTER:
 262         case NETDEV_CHANGENAME:
 263                 tipc_disable_bearer(eb_ptr->bearer->name);
 264                 break;
 265         }
 266         return NOTIFY_OK;
 267 }
 268
 269 /**
 270  * eth_addr2str - convert Ethernet address to string
 271  */
 272 static int eth_addr2str(struct tipc_media_addr *a, char *str_buf, int str_size)
 273 {
 274         if (str_size < 18)      /* 18 = strlen("aa:bb:cc:dd:ee:ff\0") */
 275                 return 1;
 276
 277         sprintf(str_buf, "%pM", a->value);
 278         return 0;
 279 }
 280
 281 /**
 282  * eth_str2addr - convert string to Ethernet address
 283  */
 284 static int eth_str2addr(struct tipc_media_addr *a, char *str_buf)
 285 {
 286         char mac[ETH_ALEN];
 287         int r;
 288
 289         r = sscanf(str_buf, "%02x:%02x:%02x:%02x:%02x:%02x",
 290                        (u32 *)&mac[0], (u32 *)&mac[1], (u32 *)&mac[2],
 291                        (u32 *)&mac[3], (u32 *)&mac[4], (u32 *)&mac[5]);
 292
 293         if (r != ETH_ALEN)
 294                 return 1;
 295
 296         eth_media_addr_set(a, mac);
 297         return 0;
 298 }
 299
 300 /**
 301  * eth_str2addr - convert Ethernet address format to message header format
 302  */
 303 static int eth_addr2msg(struct tipc_media_addr *a, char *msg_area)
 304 {
 305         memset(msg_area, 0, TIPC_MEDIA_ADDR_SIZE);
 306         msg_area[TIPC_MEDIA_TYPE_OFFSET] = TIPC_MEDIA_TYPE_ETH;
 307         memcpy(msg_area + ETH_ADDR_OFFSET, a->value, ETH_ALEN);
 308         return 0;
 309 }
 310
 311 /**
 312  * eth_str2addr - convert message header address format to Ethernet format
 313  */
 314 static int eth_msg2addr(struct tipc_media_addr *a, char *msg_area)
 315 {
 316         if (msg_area[TIPC_MEDIA_TYPE_OFFSET] != TIPC_MEDIA_TYPE_ETH)
 317                 return 1;
 318
 319         eth_media_addr_set(a, msg_area + ETH_ADDR_OFFSET);
 320         return 0;
 321 }
 322
 323 /*
 324  * Ethernet media registration info
 325  */
 326 static struct tipc_media eth_media_info = {
 327         .send_msg       = send_msg,
 328         .enable_bearer  = enable_bearer,
 329         .disable_bearer = disable_bearer,
 330         .addr2str       = eth_addr2str,
 331         .str2addr       = eth_str2addr,
 332         .addr2msg       = eth_addr2msg,
 333         .msg2addr       = eth_msg2addr,
 334         .bcast_addr     = { { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff },
 335                             TIPC_MEDIA_TYPE_ETH, 1 },
 336         .priority       = TIPC_DEF_LINK_PRI,
 337         .tolerance      = TIPC_DEF_LINK_TOL,
 338         .window         = TIPC_DEF_LINK_WIN,
 339         .type_id        = TIPC_MEDIA_TYPE_ETH,
 340         .name           = "eth"
 341 };
 342
 343 /**
 344  * tipc_eth_media_start - activate Ethernet bearer support
 345  *
 346  * Register Ethernet media type with TIPC bearer code.  Also register
 347  * with OS for notifications about device state changes.
 348  */
 349 int tipc_eth_media_start(void)
 350 {
 351         int res;
 352
 353         if (eth_started)
 354                 return -EINVAL;
 355
 356         res = tipc_register_media(&eth_media_info);
 357         if (res)
 358                 return res;
 359
 360         notifier.notifier_call = &recv_notification;
 361         notifier.priority = 0;
 362         res = register_netdevice_notifier(&notifier);
 363         if (!res)
 364                 eth_started = 1;
 365         return res;
 366 }
 367
 368 /**
 369  * tipc_eth_media_stop - deactivate Ethernet bearer support
 370  */
 371 void tipc_eth_media_stop(void)
 372 {
 373         if (!eth_started)
 374                 return;
 375
 376         flush_scheduled_work();
 377         unregister_netdevice_notifier(&notifier);
 378         eth_started = 0;
 379 }