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) 2005-2007, 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         2
  41 #define ETH_LINK_PRIORITY       TIPC_DEF_LINK_PRI
  42 #define ETH_LINK_TOLERANCE      TIPC_DEF_LINK_TOL
  43 #define ETH_LINK_WINDOW         TIPC_DEF_LINK_WIN
  44
  45 /**
  46  * struct eth_bearer - Ethernet bearer data structure
  47  * @bearer: ptr to associated "generic" bearer structure
  48  * @dev: ptr to associated Ethernet network device
  49  * @tipc_packet_type: used in binding TIPC to Ethernet driver
  50  */
  51
  52 struct eth_bearer {
  53         struct tipc_bearer *bearer;
  54         struct net_device *dev;
  55         struct packet_type tipc_packet_type;
  56 };
  57
  58 static struct eth_bearer eth_bearers[MAX_ETH_BEARERS];
  59 static int eth_started;
  60 static struct notifier_block notifier;
  61
  62 /**
  63  * send_msg - send a TIPC message out over an Ethernet interface
  64  */
  65
  66 static int send_msg(struct sk_buff *buf, struct tipc_bearer *tb_ptr,
  67                     struct tipc_media_addr *dest)
  68 {
  69         struct sk_buff *clone;
  70         struct net_device *dev;
  71         int delta;
  72
  73         clone = skb_clone(buf, GFP_ATOMIC);
  74         if (!clone)
  75                 return 0;
  76
  77         dev = ((struct eth_bearer *)(tb_ptr->usr_handle))->dev;
  78         delta = dev->hard_header_len - skb_headroom(buf);
  79
  80         if ((delta > 0) &&
  81             pskb_expand_head(clone, SKB_DATA_ALIGN(delta), 0, GFP_ATOMIC)) {
  82                 kfree_skb(clone);
  83                 return 0;
  84         }
  85
  86         skb_reset_network_header(clone);
  87         clone->dev = dev;
  88         dev_hard_header(clone, dev, ETH_P_TIPC, &dest->dev_addr.eth_addr,
  89                         dev->dev_addr, clone->len);
  90         dev_queue_xmit(clone);
  91         return 0;
  92 }
  93
  94 /**
  95  * recv_msg - handle incoming TIPC message from an Ethernet interface
  96  *
  97  * Accept only packets explicitly sent to this node, or broadcast packets;
  98  * ignores packets sent using Ethernet multicast, and traffic sent to other
  99  * nodes (which can happen if interface is running in promiscuous mode).
 100  */
 101
 102 static int recv_msg(struct sk_buff *buf, struct net_device *dev,
 103                     struct packet_type *pt, struct net_device *orig_dev)
 104 {
 105         struct eth_bearer *eb_ptr = (struct eth_bearer *)pt->af_packet_priv;
 106
 107         if (!net_eq(dev_net(dev), &init_net)) {
 108                 kfree_skb(buf);
 109                 return 0;
 110         }
 111
 112         if (likely(eb_ptr->bearer)) {
 113                 if (likely(buf->pkt_type <= PACKET_BROADCAST)) {
 114                         buf->next = NULL;
 115                         tipc_recv_msg(buf, eb_ptr->bearer);
 116                         return 0;
 117                 }
 118         }
 119         kfree_skb(buf);
 120         return 0;
 121 }
 122
 123 /**
 124  * enable_bearer - attach TIPC bearer to an Ethernet interface
 125  */
 126
 127 static int enable_bearer(struct tipc_bearer *tb_ptr)
 128 {
 129         struct net_device *dev = NULL;
 130         struct net_device *pdev = NULL;
 131         struct eth_bearer *eb_ptr = &eth_bearers[0];
 132         struct eth_bearer *stop = &eth_bearers[MAX_ETH_BEARERS];
 133         char *driver_name = strchr((const char *)tb_ptr->name, ':') + 1;
 134         int pending_dev = 0;
 135
 136         /* Find unused Ethernet bearer structure */
 137
 138         while (eb_ptr->dev) {
 139                 if (!eb_ptr->bearer)
 140                         pending_dev++;
 141                 if (++eb_ptr == stop)
 142                         return pending_dev ? -EAGAIN : -EDQUOT;
 143         }
 144
 145         /* Find device with specified name */
 146
 147         for_each_netdev(&init_net, pdev) {
 148                 if (!strncmp(pdev->name, driver_name, IFNAMSIZ)) {
 149                         dev = pdev;
 150                         break;
 151                 }
 152         }
 153         if (!dev)
 154                 return -ENODEV;
 155
 156         /* Find Ethernet bearer for device (or create one) */
 157
 158         while ((eb_ptr != stop) && eb_ptr->dev && (eb_ptr->dev != dev))
 159                 eb_ptr++;
 160         if (eb_ptr == stop)
 161                 return -EDQUOT;
 162         if (!eb_ptr->dev) {
 163                 eb_ptr->dev = dev;
 164                 eb_ptr->tipc_packet_type.type = htons(ETH_P_TIPC);
 165                 eb_ptr->tipc_packet_type.dev = dev;
 166                 eb_ptr->tipc_packet_type.func = recv_msg;
 167                 eb_ptr->tipc_packet_type.af_packet_priv = eb_ptr;
 168                 INIT_LIST_HEAD(&(eb_ptr->tipc_packet_type.list));
 169                 dev_hold(dev);
 170                 dev_add_pack(&eb_ptr->tipc_packet_type);
 171         }
 172
 173         /* Associate TIPC bearer with Ethernet bearer */
 174
 175         eb_ptr->bearer = tb_ptr;
 176         tb_ptr->usr_handle = (void *)eb_ptr;
 177         tb_ptr->mtu = dev->mtu;
 178         tb_ptr->blocked = 0;
 179         tb_ptr->addr.type = htonl(TIPC_MEDIA_TYPE_ETH);
 180         memcpy(&tb_ptr->addr.dev_addr, dev->dev_addr, ETH_ALEN);
 181         return 0;
 182 }
 183
 184 /**
 185  * disable_bearer - detach TIPC bearer from an Ethernet interface
 186  *
 187  * We really should do dev_remove_pack() here, but this function can not be
 188  * called at tasklet level. => Use eth_bearer->bearer as a flag to throw away
 189  * incoming buffers, & postpone dev_remove_pack() to eth_media_stop() on exit.
 190  */
 191
 192 static void disable_bearer(struct tipc_bearer *tb_ptr)
 193 {
 194         ((struct eth_bearer *)tb_ptr->usr_handle)->bearer = NULL;
 195 }
 196
 197 /**
 198  * recv_notification - handle device updates from OS
 199  *
 200  * Change the state of the Ethernet bearer (if any) associated with the
 201  * specified device.
 202  */
 203
 204 static int recv_notification(struct notifier_block *nb, unsigned long evt,
 205                              void *dv)
 206 {
 207         struct net_device *dev = (struct net_device *)dv;
 208         struct eth_bearer *eb_ptr = &eth_bearers[0];
 209         struct eth_bearer *stop = &eth_bearers[MAX_ETH_BEARERS];
 210
 211         if (!net_eq(dev_net(dev), &init_net))
 212                 return NOTIFY_DONE;
 213
 214         while ((eb_ptr->dev != dev)) {
 215                 if (++eb_ptr == stop)
 216                         return NOTIFY_DONE;     /* couldn't find device */
 217         }
 218         if (!eb_ptr->bearer)
 219                 return NOTIFY_DONE;             /* bearer had been disabled */
 220
 221         eb_ptr->bearer->mtu = dev->mtu;
 222
 223         switch (evt) {
 224         case NETDEV_CHANGE:
 225                 if (netif_carrier_ok(dev))
 226                         tipc_continue(eb_ptr->bearer);
 227                 else
 228                         tipc_block_bearer(eb_ptr->bearer->name);
 229                 break;
 230         case NETDEV_UP:
 231                 tipc_continue(eb_ptr->bearer);
 232                 break;
 233         case NETDEV_DOWN:
 234                 tipc_block_bearer(eb_ptr->bearer->name);
 235                 break;
 236         case NETDEV_CHANGEMTU:
 237         case NETDEV_CHANGEADDR:
 238                 tipc_block_bearer(eb_ptr->bearer->name);
 239                 tipc_continue(eb_ptr->bearer);
 240                 break;
 241         case NETDEV_UNREGISTER:
 242         case NETDEV_CHANGENAME:
 243                 tipc_disable_bearer(eb_ptr->bearer->name);
 244                 break;
 245         }
 246         return NOTIFY_OK;
 247 }
 248
 249 /**
 250  * eth_addr2str - convert Ethernet address to string
 251  */
 252
 253 static char *eth_addr2str(struct tipc_media_addr *a, char *str_buf, int str_size)
 254 {
 255         unchar *addr = (unchar *)&a->dev_addr;
 256
 257         if (str_size < 18)
 258                 *str_buf = '\0';
 259         else
 260                 sprintf(str_buf, "%pM", addr);
 261         return str_buf;
 262 }
 263
 264 /**
 265  * tipc_eth_media_start - activate Ethernet bearer support
 266  *
 267  * Register Ethernet media type with TIPC bearer code.  Also register
 268  * with OS for notifications about device state changes.
 269  */
 270
 271 int tipc_eth_media_start(void)
 272 {
 273         struct tipc_media_addr bcast_addr;
 274         int res;
 275
 276         if (eth_started)
 277                 return -EINVAL;
 278
 279         bcast_addr.type = htonl(TIPC_MEDIA_TYPE_ETH);
 280         memset(&bcast_addr.dev_addr, 0xff, ETH_ALEN);
 281
 282         memset(eth_bearers, 0, sizeof(eth_bearers));
 283
 284         res = tipc_register_media(TIPC_MEDIA_TYPE_ETH, "eth",
 285                                   enable_bearer, disable_bearer, send_msg,
 286                                   eth_addr2str, &bcast_addr, ETH_LINK_PRIORITY,
 287                                   ETH_LINK_TOLERANCE, ETH_LINK_WINDOW);
 288         if (res)
 289                 return res;
 290
 291         notifier.notifier_call = &recv_notification;
 292         notifier.priority = 0;
 293         res = register_netdevice_notifier(&notifier);
 294         if (!res)
 295                 eth_started = 1;
 296         return res;
 297 }
 298
 299 /**
 300  * tipc_eth_media_stop - deactivate Ethernet bearer support
 301  */
 302
 303 void tipc_eth_media_stop(void)
 304 {
 305         int i;
 306
 307         if (!eth_started)
 308                 return;
 309
 310         unregister_netdevice_notifier(&notifier);
 311         for (i = 0; i < MAX_ETH_BEARERS ; i++) {
 312                 if (eth_bearers[i].bearer) {
 313                         eth_bearers[i].bearer->blocked = 1;
 314                         eth_bearers[i].bearer = NULL;
 315                 }
 316                 if (eth_bearers[i].dev) {
 317                         dev_remove_pack(&eth_bearers[i].tipc_packet_type);
 318                         dev_put(eth_bearers[i].dev);
 319                 }
 320         }
 321         memset(&eth_bearers, 0, sizeof(eth_bearers));
 322         eth_started = 0;
 323 }