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 <net/tipc/tipc.h>
  38 #include <net/tipc/tipc_bearer.h>
  39 #include <net/tipc/tipc_msg.h>
  40 #include <linux/netdevice.h>
  41 #include <linux/slab.h>
  42 #include <net/net_namespace.h>
  43
  44 #define MAX_ETH_BEARERS         2
  45 #define ETH_LINK_PRIORITY       TIPC_DEF_LINK_PRI
  46 #define ETH_LINK_TOLERANCE      TIPC_DEF_LINK_TOL
  47 #define ETH_LINK_WINDOW         TIPC_DEF_LINK_WIN
  48
  49 /**
  50  * struct eth_bearer - Ethernet bearer data structure
  51  * @bearer: ptr to associated "generic" bearer structure
  52  * @dev: ptr to associated Ethernet network device
  53  * @tipc_packet_type: used in binding TIPC to Ethernet driver
  54  */
  55
  56 struct eth_bearer {
  57         struct tipc_bearer *bearer;
  58         struct net_device *dev;
  59         struct packet_type tipc_packet_type;
  60 };
  61
  62 static struct eth_bearer eth_bearers[MAX_ETH_BEARERS];
  63 static int eth_started = 0;
  64 static struct notifier_block notifier;
  65
  66 /**
  67  * send_msg - send a TIPC message out over an Ethernet interface
  68  */
  69
  70 static int send_msg(struct sk_buff *buf, struct tipc_bearer *tb_ptr,
  71                     struct tipc_media_addr *dest)
  72 {
  73         struct sk_buff *clone;
  74         struct net_device *dev;
  75         int delta;
  76
  77         clone = skb_clone(buf, GFP_ATOMIC);
  78         if (!clone)
  79                 return 0;
  80
  81         dev = ((struct eth_bearer *)(tb_ptr->usr_handle))->dev;
  82         delta = dev->hard_header_len - skb_headroom(buf);
  83
  84         if ((delta > 0) &&
  85             pskb_expand_head(clone, SKB_DATA_ALIGN(delta), 0, GFP_ATOMIC)) {
  86                 kfree_skb(clone);
  87                 return 0;
  88         }
  89
  90         skb_reset_network_header(clone);
  91         clone->dev = dev;
  92         dev_hard_header(clone, dev, ETH_P_TIPC, &dest->dev_addr.eth_addr,
  93                         dev->dev_addr, clone->len);
  94         dev_queue_xmit(clone);
  95         return 0;
  96 }
  97
  98 /**
  99  * recv_msg - handle incoming TIPC message from an Ethernet interface
 100  *
 101  * Accept only packets explicitly sent to this node, or broadcast packets;
 102  * ignores packets sent using Ethernet multicast, and traffic sent to other
 103  * nodes (which can happen if interface is running in promiscuous mode).
 104  */
 105
 106 static int recv_msg(struct sk_buff *buf, struct net_device *dev,
 107                     struct packet_type *pt, struct net_device *orig_dev)
 108 {
 109         struct eth_bearer *eb_ptr = (struct eth_bearer *)pt->af_packet_priv;
 110
 111         if (!net_eq(dev_net(dev), &init_net)) {
 112                 kfree_skb(buf);
 113                 return 0;
 114         }
 115
 116         if (likely(eb_ptr->bearer)) {
 117                 if (likely(buf->pkt_type <= PACKET_BROADCAST)) {
 118                         buf->next = NULL;
 119                         tipc_recv_msg(buf, eb_ptr->bearer);
 120                         return 0;
 121                 }
 122         }
 123         kfree_skb(buf);
 124         return 0;
 125 }
 126
 127 /**
 128  * enable_bearer - attach TIPC bearer to an Ethernet interface
 129  */
 130
 131 static int enable_bearer(struct tipc_bearer *tb_ptr)
 132 {
 133         struct net_device *dev = NULL;
 134         struct net_device *pdev = NULL;
 135         struct eth_bearer *eb_ptr = &eth_bearers[0];
 136         struct eth_bearer *stop = &eth_bearers[MAX_ETH_BEARERS];
 137         char *driver_name = strchr((const char *)tb_ptr->name, ':') + 1;
 138         int pending_dev = 0;
 139
 140         /* Find unused Ethernet bearer structure */
 141
 142         while (eb_ptr->dev) {
 143                 if (!eb_ptr->bearer)
 144                         pending_dev++;
 145                 if (++eb_ptr == stop)
 146                         return pending_dev ? -EAGAIN : -EDQUOT;
 147         }
 148
 149         /* Find device with specified name */
 150
 151         for_each_netdev(&init_net, pdev){
 152                 if (!strncmp(pdev->name, driver_name, IFNAMSIZ)) {
 153                         dev = pdev;
 154                         break;
 155                 }
 156         }
 157         if (!dev)
 158                 return -ENODEV;
 159
 160         /* Find Ethernet bearer for device (or create one) */
 161
 162         for (;(eb_ptr != stop) && eb_ptr->dev && (eb_ptr->dev != dev); eb_ptr++);
 163         if (eb_ptr == stop)
 164                 return -EDQUOT;
 165         if (!eb_ptr->dev) {
 166                 eb_ptr->dev = dev;
 167                 eb_ptr->tipc_packet_type.type = htons(ETH_P_TIPC);
 168                 eb_ptr->tipc_packet_type.dev = dev;
 169                 eb_ptr->tipc_packet_type.func = recv_msg;
 170                 eb_ptr->tipc_packet_type.af_packet_priv = eb_ptr;
 171                 INIT_LIST_HEAD(&(eb_ptr->tipc_packet_type.list));
 172                 dev_hold(dev);
 173                 dev_add_pack(&eb_ptr->tipc_packet_type);
 174         }
 175
 176         /* Associate TIPC bearer with Ethernet bearer */
 177
 178         eb_ptr->bearer = tb_ptr;
 179         tb_ptr->usr_handle = (void *)eb_ptr;
 180         tb_ptr->mtu = dev->mtu;
 181         tb_ptr->blocked = 0;
 182         tb_ptr->addr.type = htonl(TIPC_MEDIA_TYPE_ETH);
 183         memcpy(&tb_ptr->addr.dev_addr, dev->dev_addr, ETH_ALEN);
 184         return 0;
 185 }
 186
 187 /**
 188  * disable_bearer - detach TIPC bearer from an Ethernet interface
 189  *
 190  * We really should do dev_remove_pack() here, but this function can not be
 191  * called at tasklet level. => Use eth_bearer->bearer as a flag to throw away
 192  * incoming buffers, & postpone dev_remove_pack() to eth_media_stop() on exit.
 193  */
 194
 195 static void disable_bearer(struct tipc_bearer *tb_ptr)
 196 {
 197         ((struct eth_bearer *)tb_ptr->usr_handle)->bearer = NULL;
 198 }
 199
 200 /**
 201  * recv_notification - handle device updates from OS
 202  *
 203  * Change the state of the Ethernet bearer (if any) associated with the
 204  * specified device.
 205  */
 206
 207 static int recv_notification(struct notifier_block *nb, unsigned long evt,
 208                              void *dv)
 209 {
 210         struct net_device *dev = (struct net_device *)dv;
 211         struct eth_bearer *eb_ptr = &eth_bearers[0];
 212         struct eth_bearer *stop = &eth_bearers[MAX_ETH_BEARERS];
 213
 214         if (!net_eq(dev_net(dev), &init_net))
 215                 return NOTIFY_DONE;
 216
 217         while ((eb_ptr->dev != dev)) {
 218                 if (++eb_ptr == stop)
 219                         return NOTIFY_DONE;     /* couldn't find device */
 220         }
 221         if (!eb_ptr->bearer)
 222                 return NOTIFY_DONE;             /* bearer had been disabled */
 223
 224         eb_ptr->bearer->mtu = dev->mtu;
 225
 226         switch (evt) {
 227         case NETDEV_CHANGE:
 228                 if (netif_carrier_ok(dev))
 229                         tipc_continue(eb_ptr->bearer);
 230                 else
 231                         tipc_block_bearer(eb_ptr->bearer->name);
 232                 break;
 233         case NETDEV_UP:
 234                 tipc_continue(eb_ptr->bearer);
 235                 break;
 236         case NETDEV_DOWN:
 237                 tipc_block_bearer(eb_ptr->bearer->name);
 238                 break;
 239         case NETDEV_CHANGEMTU:
 240         case NETDEV_CHANGEADDR:
 241                 tipc_block_bearer(eb_ptr->bearer->name);
 242                 tipc_continue(eb_ptr->bearer);
 243                 break;
 244         case NETDEV_UNREGISTER:
 245         case NETDEV_CHANGENAME:
 246                 tipc_disable_bearer(eb_ptr->bearer->name);
 247                 break;
 248         }
 249         return NOTIFY_OK;
 250 }
 251
 252 /**
 253  * eth_addr2str - convert Ethernet address to string
 254  */
 255
 256 static char *eth_addr2str(struct tipc_media_addr *a, char *str_buf, int str_size)
 257 {
 258         unchar *addr = (unchar *)&a->dev_addr;
 259
 260         if (str_size < 18)
 261                 *str_buf = '\0';
 262         else
 263                 sprintf(str_buf, "%pM", addr);
 264         return str_buf;
 265 }
 266
 267 /**
 268  * tipc_eth_media_start - activate Ethernet bearer support
 269  *
 270  * Register Ethernet media type with TIPC bearer code.  Also register
 271  * with OS for notifications about device state changes.
 272  */
 273
 274 int tipc_eth_media_start(void)
 275 {
 276         struct tipc_media_addr bcast_addr;
 277         int res;
 278
 279         if (eth_started)
 280                 return -EINVAL;
 281
 282         bcast_addr.type = htonl(TIPC_MEDIA_TYPE_ETH);
 283         memset(&bcast_addr.dev_addr, 0xff, ETH_ALEN);
 284
 285         memset(eth_bearers, 0, sizeof(eth_bearers));
 286
 287         res = tipc_register_media(TIPC_MEDIA_TYPE_ETH, "eth",
 288                                   enable_bearer, disable_bearer, send_msg,
 289                                   eth_addr2str, &bcast_addr, ETH_LINK_PRIORITY,
 290                                   ETH_LINK_TOLERANCE, ETH_LINK_WINDOW);
 291         if (res)
 292                 return res;
 293
 294         notifier.notifier_call = &recv_notification;
 295         notifier.priority = 0;
 296         res = register_netdevice_notifier(&notifier);
 297         if (!res)
 298                 eth_started = 1;
 299         return res;
 300 }
 301
 302 /**
 303  * tipc_eth_media_stop - deactivate Ethernet bearer support
 304  */
 305
 306 void tipc_eth_media_stop(void)
 307 {
 308         int i;
 309
 310         if (!eth_started)
 311                 return;
 312
 313         unregister_netdevice_notifier(&notifier);
 314         for (i = 0; i < MAX_ETH_BEARERS ; i++) {
 315                 if (eth_bearers[i].bearer) {
 316                         eth_bearers[i].bearer->blocked = 1;
 317                         eth_bearers[i].bearer = NULL;
 318                 }
 319                 if (eth_bearers[i].dev) {
 320                         dev_remove_pack(&eth_bearers[i].tipc_packet_type);
 321                         dev_put(eth_bearers[i].dev);
 322                 }
 323         }
 324         memset(&eth_bearers, 0, sizeof(eth_bearers));
 325         eth_started = 0;
 326 }