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 <net/net_namespace.h>
  42
  43 #define MAX_ETH_BEARERS         2
  44 #define ETH_LINK_PRIORITY       TIPC_DEF_LINK_PRI
  45 #define ETH_LINK_TOLERANCE      TIPC_DEF_LINK_TOL
  46 #define ETH_LINK_WINDOW         TIPC_DEF_LINK_WIN
  47
  48 /**
  49  * struct eth_bearer - Ethernet bearer data structure
  50  * @bearer: ptr to associated "generic" bearer structure
  51  * @dev: ptr to associated Ethernet network device
  52  * @tipc_packet_type: used in binding TIPC to Ethernet driver
  53  */
  54
  55 struct eth_bearer {
  56         struct tipc_bearer *bearer;
  57         struct net_device *dev;
  58         struct packet_type tipc_packet_type;
  59 };
  60
  61 static struct eth_bearer eth_bearers[MAX_ETH_BEARERS];
  62 static int eth_started = 0;
  63 static struct notifier_block notifier;
  64
  65 /**
  66  * send_msg - send a TIPC message out over an Ethernet interface
  67  */
  68
  69 static int send_msg(struct sk_buff *buf, struct tipc_bearer *tb_ptr,
  70                     struct tipc_media_addr *dest)
  71 {
  72         struct sk_buff *clone;
  73         struct net_device *dev;
  74
  75         clone = skb_clone(buf, GFP_ATOMIC);
  76         if (clone) {
  77                 skb_reset_network_header(clone);
  78                 dev = ((struct eth_bearer *)(tb_ptr->usr_handle))->dev;
  79                 clone->dev = dev;
  80                 dev_hard_header(clone, dev, ETH_P_TIPC,
  81                                  &dest->dev_addr.eth_addr,
  82                                  dev->dev_addr, clone->len);
  83                 dev_queue_xmit(clone);
  84         }
  85         return 0;
  86 }
  87
  88 /**
  89  * recv_msg - handle incoming TIPC message from an Ethernet interface
  90  *
  91  * Accept only packets explicitly sent to this node, or broadcast packets;
  92  * ignores packets sent using Ethernet multicast, and traffic sent to other
  93  * nodes (which can happen if interface is running in promiscuous mode).
  94  * Routine truncates any Ethernet padding/CRC appended to the message,
  95  * and ensures message size matches actual length
  96  */
  97
  98 static int recv_msg(struct sk_buff *buf, struct net_device *dev,
  99                     struct packet_type *pt, struct net_device *orig_dev)
 100 {
 101         struct eth_bearer *eb_ptr = (struct eth_bearer *)pt->af_packet_priv;
 102         u32 size;
 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                         size = msg_size((struct tipc_msg *)buf->data);
 112                         skb_trim(buf, size);
 113                         if (likely(buf->len == size)) {
 114                                 buf->next = NULL;
 115                                 tipc_recv_msg(buf, eb_ptr->bearer);
 116                                 return 0;
 117                         }
 118                 }
 119         }
 120         kfree_skb(buf);
 121         return 0;
 122 }
 123
 124 /**
 125  * enable_bearer - attach TIPC bearer to an Ethernet interface
 126  */
 127
 128 static int enable_bearer(struct tipc_bearer *tb_ptr)
 129 {
 130         struct net_device *dev = NULL;
 131         struct net_device *pdev = NULL;
 132         struct eth_bearer *eb_ptr = &eth_bearers[0];
 133         struct eth_bearer *stop = &eth_bearers[MAX_ETH_BEARERS];
 134         char *driver_name = strchr((const char *)tb_ptr->name, ':') + 1;
 135
 136         /* Find device with specified name */
 137
 138         for_each_netdev(&init_net, pdev){
 139                 if (!strncmp(pdev->name, driver_name, IFNAMSIZ)) {
 140                         dev = pdev;
 141                         break;
 142                 }
 143         }
 144         if (!dev)
 145                 return -ENODEV;
 146
 147         /* Find Ethernet bearer for device (or create one) */
 148
 149         for (;(eb_ptr != stop) && eb_ptr->dev && (eb_ptr->dev != dev); eb_ptr++);
 150         if (eb_ptr == stop)
 151                 return -EDQUOT;
 152         if (!eb_ptr->dev) {
 153                 eb_ptr->dev = dev;
 154                 eb_ptr->tipc_packet_type.type = htons(ETH_P_TIPC);
 155                 eb_ptr->tipc_packet_type.dev = dev;
 156                 eb_ptr->tipc_packet_type.func = recv_msg;
 157                 eb_ptr->tipc_packet_type.af_packet_priv = eb_ptr;
 158                 INIT_LIST_HEAD(&(eb_ptr->tipc_packet_type.list));
 159                 dev_hold(dev);
 160                 dev_add_pack(&eb_ptr->tipc_packet_type);
 161         }
 162
 163         /* Associate TIPC bearer with Ethernet bearer */
 164
 165         eb_ptr->bearer = tb_ptr;
 166         tb_ptr->usr_handle = (void *)eb_ptr;
 167         tb_ptr->mtu = dev->mtu;
 168         tb_ptr->blocked = 0;
 169         tb_ptr->addr.type = htonl(TIPC_MEDIA_TYPE_ETH);
 170         memcpy(&tb_ptr->addr.dev_addr, dev->dev_addr, ETH_ALEN);
 171         return 0;
 172 }
 173
 174 /**
 175  * disable_bearer - detach TIPC bearer from an Ethernet interface
 176  *
 177  * We really should do dev_remove_pack() here, but this function can not be
 178  * called at tasklet level. => Use eth_bearer->bearer as a flag to throw away
 179  * incoming buffers, & postpone dev_remove_pack() to eth_media_stop() on exit.
 180  */
 181
 182 static void disable_bearer(struct tipc_bearer *tb_ptr)
 183 {
 184         ((struct eth_bearer *)tb_ptr->usr_handle)->bearer = NULL;
 185 }
 186
 187 /**
 188  * recv_notification - handle device updates from OS
 189  *
 190  * Change the state of the Ethernet bearer (if any) associated with the
 191  * specified device.
 192  */
 193
 194 static int recv_notification(struct notifier_block *nb, unsigned long evt,
 195                              void *dv)
 196 {
 197         struct net_device *dev = (struct net_device *)dv;
 198         struct eth_bearer *eb_ptr = &eth_bearers[0];
 199         struct eth_bearer *stop = &eth_bearers[MAX_ETH_BEARERS];
 200
 201         if (!net_eq(dev_net(dev), &init_net))
 202                 return NOTIFY_DONE;
 203
 204         while ((eb_ptr->dev != dev)) {
 205                 if (++eb_ptr == stop)
 206                         return NOTIFY_DONE;     /* couldn't find device */
 207         }
 208         if (!eb_ptr->bearer)
 209                 return NOTIFY_DONE;             /* bearer had been disabled */
 210
 211         eb_ptr->bearer->mtu = dev->mtu;
 212
 213         switch (evt) {
 214         case NETDEV_CHANGE:
 215                 if (netif_carrier_ok(dev))
 216                         tipc_continue(eb_ptr->bearer);
 217                 else
 218                         tipc_block_bearer(eb_ptr->bearer->name);
 219                 break;
 220         case NETDEV_UP:
 221                 tipc_continue(eb_ptr->bearer);
 222                 break;
 223         case NETDEV_DOWN:
 224                 tipc_block_bearer(eb_ptr->bearer->name);
 225                 break;
 226         case NETDEV_CHANGEMTU:
 227         case NETDEV_CHANGEADDR:
 228                 tipc_block_bearer(eb_ptr->bearer->name);
 229                 tipc_continue(eb_ptr->bearer);
 230                 break;
 231         case NETDEV_UNREGISTER:
 232         case NETDEV_CHANGENAME:
 233                 tipc_disable_bearer(eb_ptr->bearer->name);
 234                 break;
 235         }
 236         return NOTIFY_OK;
 237 }
 238
 239 /**
 240  * eth_addr2str - convert Ethernet address to string
 241  */
 242
 243 static char *eth_addr2str(struct tipc_media_addr *a, char *str_buf, int str_size)
 244 {
 245         unchar *addr = (unchar *)&a->dev_addr;
 246
 247         if (str_size < 18)
 248                 *str_buf = '\0';
 249         else
 250                 sprintf(str_buf, "%pM", addr);
 251         return str_buf;
 252 }
 253
 254 /**
 255  * tipc_eth_media_start - activate Ethernet bearer support
 256  *
 257  * Register Ethernet media type with TIPC bearer code.  Also register
 258  * with OS for notifications about device state changes.
 259  */
 260
 261 int tipc_eth_media_start(void)
 262 {
 263         struct tipc_media_addr bcast_addr;
 264         int res;
 265
 266         if (eth_started)
 267                 return -EINVAL;
 268
 269         bcast_addr.type = htonl(TIPC_MEDIA_TYPE_ETH);
 270         memset(&bcast_addr.dev_addr, 0xff, ETH_ALEN);
 271
 272         memset(eth_bearers, 0, sizeof(eth_bearers));
 273
 274         res = tipc_register_media(TIPC_MEDIA_TYPE_ETH, "eth",
 275                                   enable_bearer, disable_bearer, send_msg,
 276                                   eth_addr2str, &bcast_addr, ETH_LINK_PRIORITY,
 277                                   ETH_LINK_TOLERANCE, ETH_LINK_WINDOW);
 278         if (res)
 279                 return res;
 280
 281         notifier.notifier_call = &recv_notification;
 282         notifier.priority = 0;
 283         res = register_netdevice_notifier(&notifier);
 284         if (!res)
 285                 eth_started = 1;
 286         return res;
 287 }
 288
 289 /**
 290  * tipc_eth_media_stop - deactivate Ethernet bearer support
 291  */
 292
 293 void tipc_eth_media_stop(void)
 294 {
 295         int i;
 296
 297         if (!eth_started)
 298                 return;
 299
 300         unregister_netdevice_notifier(&notifier);
 301         for (i = 0; i < MAX_ETH_BEARERS ; i++) {
 302                 if (eth_bearers[i].bearer) {
 303                         eth_bearers[i].bearer->blocked = 1;
 304                         eth_bearers[i].bearer = NULL;
 305                 }
 306                 if (eth_bearers[i].dev) {
 307                         dev_remove_pack(&eth_bearers[i].tipc_packet_type);
 308                         dev_put(eth_bearers[i].dev);
 309                 }
 310         }
 311         memset(&eth_bearers, 0, sizeof(eth_bearers));
 312         eth_started = 0;
 313 }