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  */
  50
  51 struct eth_bearer {
  52         struct tipc_bearer *bearer;
  53         struct net_device *dev;
  54         struct packet_type tipc_packet_type;
  55 };
  56
  57 static struct media eth_media_info;
  58 static struct eth_bearer eth_bearers[MAX_ETH_BEARERS];
  59 static int eth_started;
  60 static struct notifier_block notifier;
  61
  62 /**
  63  * eth_media_addr_set - initialize Ethernet media address structure
  64  *
  65  * Media-dependent "value" field stores MAC address in first 6 bytes
  66  * and zeroes out the remaining bytes.
  67  */
  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
  81 static int send_msg(struct sk_buff *buf, struct tipc_bearer *tb_ptr,
  82                     struct tipc_media_addr *dest)
  83 {
  84         struct sk_buff *clone;
  85         struct net_device *dev;
  86         int delta;
  87
  88         clone = skb_clone(buf, GFP_ATOMIC);
  89         if (!clone)
  90                 return 0;
  91
  92         dev = ((struct eth_bearer *)(tb_ptr->usr_handle))->dev;
  93         delta = dev->hard_header_len - skb_headroom(buf);
  94
  95         if ((delta > 0) &&
  96             pskb_expand_head(clone, SKB_DATA_ALIGN(delta), 0, GFP_ATOMIC)) {
  97                 kfree_skb(clone);
  98                 return 0;
  99         }
 100
 101         skb_reset_network_header(clone);
 102         clone->dev = dev;
 103         dev_hard_header(clone, dev, ETH_P_TIPC, dest->value,
 104                         dev->dev_addr, clone->len);
 105         dev_queue_xmit(clone);
 106         return 0;
 107 }
 108
 109 /**
 110  * recv_msg - handle incoming TIPC message from an Ethernet interface
 111  *
 112  * Accept only packets explicitly sent to this node, or broadcast packets;
 113  * ignores packets sent using Ethernet multicast, and traffic sent to other
 114  * nodes (which can happen if interface is running in promiscuous mode).
 115  */
 116
 117 static int recv_msg(struct sk_buff *buf, struct net_device *dev,
 118                     struct packet_type *pt, struct net_device *orig_dev)
 119 {
 120         struct eth_bearer *eb_ptr = (struct eth_bearer *)pt->af_packet_priv;
 121
 122         if (!net_eq(dev_net(dev), &init_net)) {
 123                 kfree_skb(buf);
 124                 return 0;
 125         }
 126
 127         if (likely(eb_ptr->bearer)) {
 128                 if (likely(buf->pkt_type <= PACKET_BROADCAST)) {
 129                         buf->next = NULL;
 130                         tipc_recv_msg(buf, eb_ptr->bearer);
 131                         return 0;
 132                 }
 133         }
 134         kfree_skb(buf);
 135         return 0;
 136 }
 137
 138 /**
 139  * enable_bearer - attach TIPC bearer to an Ethernet interface
 140  */
 141
 142 static int enable_bearer(struct tipc_bearer *tb_ptr)
 143 {
 144         struct net_device *dev = NULL;
 145         struct net_device *pdev = NULL;
 146         struct eth_bearer *eb_ptr = &eth_bearers[0];
 147         struct eth_bearer *stop = &eth_bearers[MAX_ETH_BEARERS];
 148         char *driver_name = strchr((const char *)tb_ptr->name, ':') + 1;
 149         int pending_dev = 0;
 150
 151         /* Find unused Ethernet bearer structure */
 152
 153         while (eb_ptr->dev) {
 154                 if (!eb_ptr->bearer)
 155                         pending_dev++;
 156                 if (++eb_ptr == stop)
 157                         return pending_dev ? -EAGAIN : -EDQUOT;
 158         }
 159
 160         /* Find device with specified name */
 161
 162         read_lock(&dev_base_lock);
 163         for_each_netdev(&init_net, pdev) {
 164                 if (!strncmp(pdev->name, driver_name, IFNAMSIZ)) {
 165                         dev = pdev;
 166                         dev_hold(dev);
 167                         break;
 168                 }
 169         }
 170         read_unlock(&dev_base_lock);
 171         if (!dev)
 172                 return -ENODEV;
 173
 174         /* Create Ethernet bearer for device */
 175
 176         eb_ptr->dev = dev;
 177         eb_ptr->tipc_packet_type.type = htons(ETH_P_TIPC);
 178         eb_ptr->tipc_packet_type.dev = dev;
 179         eb_ptr->tipc_packet_type.func = recv_msg;
 180         eb_ptr->tipc_packet_type.af_packet_priv = eb_ptr;
 181         INIT_LIST_HEAD(&(eb_ptr->tipc_packet_type.list));
 182         dev_add_pack(&eb_ptr->tipc_packet_type);
 183
 184         /* Associate TIPC bearer with Ethernet bearer */
 185
 186         eb_ptr->bearer = tb_ptr;
 187         tb_ptr->usr_handle = (void *)eb_ptr;
 188         tb_ptr->mtu = dev->mtu;
 189         tb_ptr->blocked = 0;
 190         eth_media_addr_set(&tb_ptr->addr, (char *)dev->dev_addr);
 191         return 0;
 192 }
 193
 194 /**
 195  * disable_bearer - detach TIPC bearer from an Ethernet interface
 196  *
 197  * We really should do dev_remove_pack() here, but this function can not be
 198  * called at tasklet level. => Use eth_bearer->bearer as a flag to throw away
 199  * incoming buffers, & postpone dev_remove_pack() to eth_media_stop() on exit.
 200  */
 201
 202 static void disable_bearer(struct tipc_bearer *tb_ptr)
 203 {
 204         ((struct eth_bearer *)tb_ptr->usr_handle)->bearer = NULL;
 205 }
 206
 207 /**
 208  * recv_notification - handle device updates from OS
 209  *
 210  * Change the state of the Ethernet bearer (if any) associated with the
 211  * specified device.
 212  */
 213
 214 static int recv_notification(struct notifier_block *nb, unsigned long evt,
 215                              void *dv)
 216 {
 217         struct net_device *dev = (struct net_device *)dv;
 218         struct eth_bearer *eb_ptr = &eth_bearers[0];
 219         struct eth_bearer *stop = &eth_bearers[MAX_ETH_BEARERS];
 220
 221         if (!net_eq(dev_net(dev), &init_net))
 222                 return NOTIFY_DONE;
 223
 224         while ((eb_ptr->dev != dev)) {
 225                 if (++eb_ptr == stop)
 226                         return NOTIFY_DONE;     /* couldn't find device */
 227         }
 228         if (!eb_ptr->bearer)
 229                 return NOTIFY_DONE;             /* bearer had been disabled */
 230
 231         eb_ptr->bearer->mtu = dev->mtu;
 232
 233         switch (evt) {
 234         case NETDEV_CHANGE:
 235                 if (netif_carrier_ok(dev))
 236                         tipc_continue(eb_ptr->bearer);
 237                 else
 238                         tipc_block_bearer(eb_ptr->bearer->name);
 239                 break;
 240         case NETDEV_UP:
 241                 tipc_continue(eb_ptr->bearer);
 242                 break;
 243         case NETDEV_DOWN:
 244                 tipc_block_bearer(eb_ptr->bearer->name);
 245                 break;
 246         case NETDEV_CHANGEMTU:
 247         case NETDEV_CHANGEADDR:
 248                 tipc_block_bearer(eb_ptr->bearer->name);
 249                 tipc_continue(eb_ptr->bearer);
 250                 break;
 251         case NETDEV_UNREGISTER:
 252         case NETDEV_CHANGENAME:
 253                 tipc_disable_bearer(eb_ptr->bearer->name);
 254                 break;
 255         }
 256         return NOTIFY_OK;
 257 }
 258
 259 /**
 260  * eth_addr2str - convert Ethernet address to string
 261  */
 262
 263 static int eth_addr2str(struct tipc_media_addr *a, char *str_buf, int str_size)
 264 {
 265         if (str_size < 18)      /* 18 = strlen("aa:bb:cc:dd:ee:ff\0") */
 266                 return 1;
 267
 268         sprintf(str_buf, "%pM", a->value);
 269         return 0;
 270 }
 271
 272 /**
 273  * eth_str2addr - convert string to Ethernet address
 274  */
 275
 276 static int eth_str2addr(struct tipc_media_addr *a, char *str_buf)
 277 {
 278         char mac[ETH_ALEN];
 279         int r;
 280
 281         r = sscanf(str_buf, "%02x:%02x:%02x:%02x:%02x:%02x",
 282                        (u32 *)&mac[0], (u32 *)&mac[1], (u32 *)&mac[2],
 283                        (u32 *)&mac[3], (u32 *)&mac[4], (u32 *)&mac[5]);
 284
 285         if (r != ETH_ALEN)
 286                 return 1;
 287
 288         eth_media_addr_set(a, mac);
 289         return 0;
 290 }
 291
 292 /**
 293  * eth_str2addr - convert Ethernet address format to message header format
 294  */
 295
 296 static int eth_addr2msg(struct tipc_media_addr *a, char *msg_area)
 297 {
 298         memset(msg_area, 0, TIPC_MEDIA_ADDR_SIZE);
 299         msg_area[TIPC_MEDIA_TYPE_OFFSET] = TIPC_MEDIA_TYPE_ETH;
 300         memcpy(msg_area + ETH_ADDR_OFFSET, a->value, ETH_ALEN);
 301         return 0;
 302 }
 303
 304 /**
 305  * eth_str2addr - convert message header address format to Ethernet format
 306  */
 307
 308 static int eth_msg2addr(struct tipc_media_addr *a, char *msg_area)
 309 {
 310         if (msg_area[TIPC_MEDIA_TYPE_OFFSET] != TIPC_MEDIA_TYPE_ETH)
 311                 return 1;
 312
 313         eth_media_addr_set(a, msg_area + ETH_ADDR_OFFSET);
 314         return 0;
 315 }
 316
 317 /*
 318  * Ethernet media registration info
 319  */
 320
 321 static struct media eth_media_info = {
 322         .send_msg       = send_msg,
 323         .enable_bearer  = enable_bearer,
 324         .disable_bearer = disable_bearer,
 325         .addr2str       = eth_addr2str,
 326         .str2addr       = eth_str2addr,
 327         .addr2msg       = eth_addr2msg,
 328         .msg2addr       = eth_msg2addr,
 329         .bcast_addr     = { { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff },
 330                             TIPC_MEDIA_TYPE_ETH, 1 },
 331         .priority       = TIPC_DEF_LINK_PRI,
 332         .tolerance      = TIPC_DEF_LINK_TOL,
 333         .window         = TIPC_DEF_LINK_WIN,
 334         .type_id        = TIPC_MEDIA_TYPE_ETH,
 335         .name           = "eth"
 336 };
 337
 338 /**
 339  * tipc_eth_media_start - activate Ethernet bearer support
 340  *
 341  * Register Ethernet media type with TIPC bearer code.  Also register
 342  * with OS for notifications about device state changes.
 343  */
 344
 345 int tipc_eth_media_start(void)
 346 {
 347         int res;
 348
 349         if (eth_started)
 350                 return -EINVAL;
 351
 352         memset(eth_bearers, 0, sizeof(eth_bearers));
 353
 354         res = tipc_register_media(&eth_media_info);
 355         if (res)
 356                 return res;
 357
 358         notifier.notifier_call = &recv_notification;
 359         notifier.priority = 0;
 360         res = register_netdevice_notifier(&notifier);
 361         if (!res)
 362                 eth_started = 1;
 363         return res;
 364 }
 365
 366 /**
 367  * tipc_eth_media_stop - deactivate Ethernet bearer support
 368  */
 369
 370 void tipc_eth_media_stop(void)
 371 {
 372         int i;
 373
 374         if (!eth_started)
 375                 return;
 376
 377         unregister_netdevice_notifier(&notifier);
 378         for (i = 0; i < MAX_ETH_BEARERS ; i++) {
 379                 if (eth_bearers[i].bearer) {
 380                         eth_bearers[i].bearer->blocked = 1;
 381                         eth_bearers[i].bearer = NULL;
 382                 }
 383                 if (eth_bearers[i].dev) {
 384                         dev_remove_pack(&eth_bearers[i].tipc_packet_type);
 385                         dev_put(eth_bearers[i].dev);
 386                 }
 387         }
 388         memset(&eth_bearers, 0, sizeof(eth_bearers));
 389         eth_started = 0;
 390 }