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 /**
  43  * struct eth_bearer - Ethernet bearer data structure
  44  * @bearer: ptr to associated "generic" bearer structure
  45  * @dev: ptr to associated Ethernet network device
  46  * @tipc_packet_type: used in binding TIPC to Ethernet driver
  47  */
  48
  49 struct eth_bearer {
  50         struct tipc_bearer *bearer;
  51         struct net_device *dev;
  52         struct packet_type tipc_packet_type;
  53 };
  54
  55 static struct eth_bearer eth_bearers[MAX_ETH_BEARERS];
  56 static int eth_started;
  57 static struct notifier_block notifier;
  58
  59 /**
  60  * send_msg - send a TIPC message out over an Ethernet interface
  61  */
  62
  63 static int send_msg(struct sk_buff *buf, struct tipc_bearer *tb_ptr,
  64                     struct tipc_media_addr *dest)
  65 {
  66         struct sk_buff *clone;
  67         struct net_device *dev;
  68         int delta;
  69
  70         clone = skb_clone(buf, GFP_ATOMIC);
  71         if (!clone)
  72                 return 0;
  73
  74         dev = ((struct eth_bearer *)(tb_ptr->usr_handle))->dev;
  75         delta = dev->hard_header_len - skb_headroom(buf);
  76
  77         if ((delta > 0) &&
  78             pskb_expand_head(clone, SKB_DATA_ALIGN(delta), 0, GFP_ATOMIC)) {
  79                 kfree_skb(clone);
  80                 return 0;
  81         }
  82
  83         skb_reset_network_header(clone);
  84         clone->dev = dev;
  85         dev_hard_header(clone, dev, ETH_P_TIPC, &dest->dev_addr.eth_addr,
  86                         dev->dev_addr, clone->len);
  87         dev_queue_xmit(clone);
  88         return 0;
  89 }
  90
  91 /**
  92  * recv_msg - handle incoming TIPC message from an Ethernet interface
  93  *
  94  * Accept only packets explicitly sent to this node, or broadcast packets;
  95  * ignores packets sent using Ethernet multicast, and traffic sent to other
  96  * nodes (which can happen if interface is running in promiscuous mode).
  97  */
  98
  99 static int recv_msg(struct sk_buff *buf, struct net_device *dev,
 100                     struct packet_type *pt, struct net_device *orig_dev)
 101 {
 102         struct eth_bearer *eb_ptr = (struct eth_bearer *)pt->af_packet_priv;
 103
 104         if (!net_eq(dev_net(dev), &init_net)) {
 105                 kfree_skb(buf);
 106                 return 0;
 107         }
 108
 109         if (likely(eb_ptr->bearer)) {
 110                 if (likely(buf->pkt_type <= PACKET_BROADCAST)) {
 111                         buf->next = NULL;
 112                         tipc_recv_msg(buf, eb_ptr->bearer);
 113                         return 0;
 114                 }
 115         }
 116         kfree_skb(buf);
 117         return 0;
 118 }
 119
 120 /**
 121  * enable_bearer - attach TIPC bearer to an Ethernet interface
 122  */
 123
 124 static int enable_bearer(struct tipc_bearer *tb_ptr)
 125 {
 126         struct net_device *dev = NULL;
 127         struct net_device *pdev = NULL;
 128         struct eth_bearer *eb_ptr = &eth_bearers[0];
 129         struct eth_bearer *stop = &eth_bearers[MAX_ETH_BEARERS];
 130         char *driver_name = strchr((const char *)tb_ptr->name, ':') + 1;
 131         int pending_dev = 0;
 132
 133         /* Find unused Ethernet bearer structure */
 134
 135         while (eb_ptr->dev) {
 136                 if (!eb_ptr->bearer)
 137                         pending_dev++;
 138                 if (++eb_ptr == stop)
 139                         return pending_dev ? -EAGAIN : -EDQUOT;
 140         }
 141
 142         /* Find device with specified name */
 143
 144         read_lock(&dev_base_lock);
 145         for_each_netdev(&init_net, pdev) {
 146                 if (!strncmp(pdev->name, driver_name, IFNAMSIZ)) {
 147                         dev = pdev;
 148                         dev_hold(dev);
 149                         break;
 150                 }
 151         }
 152         read_unlock(&dev_base_lock);
 153         if (!dev)
 154                 return -ENODEV;
 155
 156         /* Create Ethernet bearer for device */
 157
 158         eb_ptr->dev = dev;
 159         eb_ptr->tipc_packet_type.type = htons(ETH_P_TIPC);
 160         eb_ptr->tipc_packet_type.dev = dev;
 161         eb_ptr->tipc_packet_type.func = recv_msg;
 162         eb_ptr->tipc_packet_type.af_packet_priv = eb_ptr;
 163         INIT_LIST_HEAD(&(eb_ptr->tipc_packet_type.list));
 164         dev_add_pack(&eb_ptr->tipc_packet_type);
 165
 166         /* Associate TIPC bearer with Ethernet bearer */
 167
 168         eb_ptr->bearer = tb_ptr;
 169         tb_ptr->usr_handle = (void *)eb_ptr;
 170         tb_ptr->mtu = dev->mtu;
 171         tb_ptr->blocked = 0;
 172         tb_ptr->addr.type = htonl(TIPC_MEDIA_TYPE_ETH);
 173         memcpy(&tb_ptr->addr.dev_addr, dev->dev_addr, ETH_ALEN);
 174         return 0;
 175 }
 176
 177 /**
 178  * disable_bearer - detach TIPC bearer from an Ethernet interface
 179  *
 180  * We really should do dev_remove_pack() here, but this function can not be
 181  * called at tasklet level. => Use eth_bearer->bearer as a flag to throw away
 182  * incoming buffers, & postpone dev_remove_pack() to eth_media_stop() on exit.
 183  */
 184
 185 static void disable_bearer(struct tipc_bearer *tb_ptr)
 186 {
 187         ((struct eth_bearer *)tb_ptr->usr_handle)->bearer = NULL;
 188 }
 189
 190 /**
 191  * recv_notification - handle device updates from OS
 192  *
 193  * Change the state of the Ethernet bearer (if any) associated with the
 194  * specified device.
 195  */
 196
 197 static int recv_notification(struct notifier_block *nb, unsigned long evt,
 198                              void *dv)
 199 {
 200         struct net_device *dev = (struct net_device *)dv;
 201         struct eth_bearer *eb_ptr = &eth_bearers[0];
 202         struct eth_bearer *stop = &eth_bearers[MAX_ETH_BEARERS];
 203
 204         if (!net_eq(dev_net(dev), &init_net))
 205                 return NOTIFY_DONE;
 206
 207         while ((eb_ptr->dev != dev)) {
 208                 if (++eb_ptr == stop)
 209                         return NOTIFY_DONE;     /* couldn't find device */
 210         }
 211         if (!eb_ptr->bearer)
 212                 return NOTIFY_DONE;             /* bearer had been disabled */
 213
 214         eb_ptr->bearer->mtu = dev->mtu;
 215
 216         switch (evt) {
 217         case NETDEV_CHANGE:
 218                 if (netif_carrier_ok(dev))
 219                         tipc_continue(eb_ptr->bearer);
 220                 else
 221                         tipc_block_bearer(eb_ptr->bearer->name);
 222                 break;
 223         case NETDEV_UP:
 224                 tipc_continue(eb_ptr->bearer);
 225                 break;
 226         case NETDEV_DOWN:
 227                 tipc_block_bearer(eb_ptr->bearer->name);
 228                 break;
 229         case NETDEV_CHANGEMTU:
 230         case NETDEV_CHANGEADDR:
 231                 tipc_block_bearer(eb_ptr->bearer->name);
 232                 tipc_continue(eb_ptr->bearer);
 233                 break;
 234         case NETDEV_UNREGISTER:
 235         case NETDEV_CHANGENAME:
 236                 tipc_disable_bearer(eb_ptr->bearer->name);
 237                 break;
 238         }
 239         return NOTIFY_OK;
 240 }
 241
 242 /**
 243  * eth_addr2str - convert Ethernet address to string
 244  */
 245
 246 static char *eth_addr2str(struct tipc_media_addr *a, char *str_buf, int str_size)
 247 {
 248         unchar *addr = (unchar *)&a->dev_addr;
 249
 250         if (str_size < 18)
 251                 *str_buf = '\0';
 252         else
 253                 sprintf(str_buf, "%pM", addr);
 254         return str_buf;
 255 }
 256
 257 /*
 258  * Ethernet media registration info
 259  */
 260
 261 static struct media eth_media_info = {
 262         .send_msg       = send_msg,
 263         .enable_bearer  = enable_bearer,
 264         .disable_bearer = disable_bearer,
 265         .addr2str       = eth_addr2str,
 266         .bcast_addr     = { htonl(TIPC_MEDIA_TYPE_ETH),
 267                             { {0xff, 0xff, 0xff, 0xff, 0xff, 0xff} } },
 268         .priority       = TIPC_DEF_LINK_PRI,
 269         .tolerance      = TIPC_DEF_LINK_TOL,
 270         .window         = TIPC_DEF_LINK_WIN,
 271         .type_id        = TIPC_MEDIA_TYPE_ETH,
 272         .name           = "eth"
 273 };
 274
 275 /**
 276  * tipc_eth_media_start - activate Ethernet bearer support
 277  *
 278  * Register Ethernet media type with TIPC bearer code.  Also register
 279  * with OS for notifications about device state changes.
 280  */
 281
 282 int tipc_eth_media_start(void)
 283 {
 284         int res;
 285
 286         if (eth_started)
 287                 return -EINVAL;
 288
 289         memset(eth_bearers, 0, sizeof(eth_bearers));
 290
 291         res = tipc_register_media(&eth_media_info);
 292         if (res)
 293                 return res;
 294
 295         notifier.notifier_call = &recv_notification;
 296         notifier.priority = 0;
 297         res = register_netdevice_notifier(&notifier);
 298         if (!res)
 299                 eth_started = 1;
 300         return res;
 301 }
 302
 303 /**
 304  * tipc_eth_media_stop - deactivate Ethernet bearer support
 305  */
 306
 307 void tipc_eth_media_stop(void)
 308 {
 309         int i;
 310
 311         if (!eth_started)
 312                 return;
 313
 314         unregister_netdevice_notifier(&notifier);
 315         for (i = 0; i < MAX_ETH_BEARERS ; i++) {
 316                 if (eth_bearers[i].bearer) {
 317                         eth_bearers[i].bearer->blocked = 1;
 318                         eth_bearers[i].bearer = NULL;
 319                 }
 320                 if (eth_bearers[i].dev) {
 321                         dev_remove_pack(&eth_bearers[i].tipc_packet_type);
 322                         dev_put(eth_bearers[i].dev);
 323                 }
 324         }
 325         memset(&eth_bearers, 0, sizeof(eth_bearers));
 326         eth_started = 0;
 327 }