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
  76         clone = skb_clone(buf, GFP_ATOMIC);
  77         if (clone) {
  78                 skb_reset_network_header(clone);
  79                 dev = ((struct eth_bearer *)(tb_ptr->usr_handle))->dev;
  80                 clone->dev = dev;
  81                 dev_hard_header(clone, dev, ETH_P_TIPC,
  82                                  &dest->dev_addr.eth_addr,
  83                                  dev->dev_addr, clone->len);
  84                 dev_queue_xmit(clone);
  85         }
  86         return 0;
  87 }
  88
  89 /**
  90  * recv_msg - handle incoming TIPC message from an Ethernet interface
  91  *
  92  * Accept only packets explicitly sent to this node, or broadcast packets;
  93  * ignores packets sent using Ethernet multicast, and traffic sent to other
  94  * nodes (which can happen if interface is running in promiscuous mode).
  95  * Routine truncates any Ethernet padding/CRC appended to the message,
  96  * and ensures message size matches actual length
  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         u32 size;
 104
 105         if (!net_eq(dev_net(dev), &init_net)) {
 106                 kfree_skb(buf);
 107                 return 0;
 108         }
 109
 110         if (likely(eb_ptr->bearer)) {
 111                 if (likely(buf->pkt_type <= PACKET_BROADCAST)) {
 112                         size = msg_size((struct tipc_msg *)buf->data);
 113                         skb_trim(buf, size);
 114                         if (likely(buf->len == size)) {
 115                                 buf->next = NULL;
 116                                 tipc_recv_msg(buf, eb_ptr->bearer);
 117                                 return 0;
 118                         }
 119                 }
 120         }
 121         kfree_skb(buf);
 122         return 0;
 123 }
 124
 125 /**
 126  * enable_bearer - attach TIPC bearer to an Ethernet interface
 127  */
 128
 129 static int enable_bearer(struct tipc_bearer *tb_ptr)
 130 {
 131         struct net_device *dev = NULL;
 132         struct net_device *pdev = NULL;
 133         struct eth_bearer *eb_ptr = &eth_bearers[0];
 134         struct eth_bearer *stop = &eth_bearers[MAX_ETH_BEARERS];
 135         char *driver_name = strchr((const char *)tb_ptr->name, ':') + 1;
 136
 137         /* Find device with specified name */
 138
 139         for_each_netdev(&init_net, pdev){
 140                 if (!strncmp(pdev->name, driver_name, IFNAMSIZ)) {
 141                         dev = pdev;
 142                         break;
 143                 }
 144         }
 145         if (!dev)
 146                 return -ENODEV;
 147
 148         /* Find Ethernet bearer for device (or create one) */
 149
 150         for (;(eb_ptr != stop) && eb_ptr->dev && (eb_ptr->dev != dev); eb_ptr++);
 151         if (eb_ptr == stop)
 152                 return -EDQUOT;
 153         if (!eb_ptr->dev) {
 154                 eb_ptr->dev = dev;
 155                 eb_ptr->tipc_packet_type.type = htons(ETH_P_TIPC);
 156                 eb_ptr->tipc_packet_type.dev = dev;
 157                 eb_ptr->tipc_packet_type.func = recv_msg;
 158                 eb_ptr->tipc_packet_type.af_packet_priv = eb_ptr;
 159                 INIT_LIST_HEAD(&(eb_ptr->tipc_packet_type.list));
 160                 dev_hold(dev);
 161                 dev_add_pack(&eb_ptr->tipc_packet_type);
 162         }
 163
 164         /* Associate TIPC bearer with Ethernet bearer */
 165
 166         eb_ptr->bearer = tb_ptr;
 167         tb_ptr->usr_handle = (void *)eb_ptr;
 168         tb_ptr->mtu = dev->mtu;
 169         tb_ptr->blocked = 0;
 170         tb_ptr->addr.type = htonl(TIPC_MEDIA_TYPE_ETH);
 171         memcpy(&tb_ptr->addr.dev_addr, dev->dev_addr, ETH_ALEN);
 172         return 0;
 173 }
 174
 175 /**
 176  * disable_bearer - detach TIPC bearer from an Ethernet interface
 177  *
 178  * We really should do dev_remove_pack() here, but this function can not be
 179  * called at tasklet level. => Use eth_bearer->bearer as a flag to throw away
 180  * incoming buffers, & postpone dev_remove_pack() to eth_media_stop() on exit.
 181  */
 182
 183 static void disable_bearer(struct tipc_bearer *tb_ptr)
 184 {
 185         ((struct eth_bearer *)tb_ptr->usr_handle)->bearer = NULL;
 186 }
 187
 188 /**
 189  * recv_notification - handle device updates from OS
 190  *
 191  * Change the state of the Ethernet bearer (if any) associated with the
 192  * specified device.
 193  */
 194
 195 static int recv_notification(struct notifier_block *nb, unsigned long evt,
 196                              void *dv)
 197 {
 198         struct net_device *dev = (struct net_device *)dv;
 199         struct eth_bearer *eb_ptr = &eth_bearers[0];
 200         struct eth_bearer *stop = &eth_bearers[MAX_ETH_BEARERS];
 201
 202         if (!net_eq(dev_net(dev), &init_net))
 203                 return NOTIFY_DONE;
 204
 205         while ((eb_ptr->dev != dev)) {
 206                 if (++eb_ptr == stop)
 207                         return NOTIFY_DONE;     /* couldn't find device */
 208         }
 209         if (!eb_ptr->bearer)
 210                 return NOTIFY_DONE;             /* bearer had been disabled */
 211
 212         eb_ptr->bearer->mtu = dev->mtu;
 213
 214         switch (evt) {
 215         case NETDEV_CHANGE:
 216                 if (netif_carrier_ok(dev))
 217                         tipc_continue(eb_ptr->bearer);
 218                 else
 219                         tipc_block_bearer(eb_ptr->bearer->name);
 220                 break;
 221         case NETDEV_UP:
 222                 tipc_continue(eb_ptr->bearer);
 223                 break;
 224         case NETDEV_DOWN:
 225                 tipc_block_bearer(eb_ptr->bearer->name);
 226                 break;
 227         case NETDEV_CHANGEMTU:
 228         case NETDEV_CHANGEADDR:
 229                 tipc_block_bearer(eb_ptr->bearer->name);
 230                 tipc_continue(eb_ptr->bearer);
 231                 break;
 232         case NETDEV_UNREGISTER:
 233         case NETDEV_CHANGENAME:
 234                 tipc_disable_bearer(eb_ptr->bearer->name);
 235                 break;
 236         }
 237         return NOTIFY_OK;
 238 }
 239
 240 /**
 241  * eth_addr2str - convert Ethernet address to string
 242  */
 243
 244 static char *eth_addr2str(struct tipc_media_addr *a, char *str_buf, int str_size)
 245 {
 246         unchar *addr = (unchar *)&a->dev_addr;
 247
 248         if (str_size < 18)
 249                 *str_buf = '\0';
 250         else
 251                 sprintf(str_buf, "%pM", addr);
 252         return str_buf;
 253 }
 254
 255 /**
 256  * tipc_eth_media_start - activate Ethernet bearer support
 257  *
 258  * Register Ethernet media type with TIPC bearer code.  Also register
 259  * with OS for notifications about device state changes.
 260  */
 261
 262 int tipc_eth_media_start(void)
 263 {
 264         struct tipc_media_addr bcast_addr;
 265         int res;
 266
 267         if (eth_started)
 268                 return -EINVAL;
 269
 270         bcast_addr.type = htonl(TIPC_MEDIA_TYPE_ETH);
 271         memset(&bcast_addr.dev_addr, 0xff, ETH_ALEN);
 272
 273         memset(eth_bearers, 0, sizeof(eth_bearers));
 274
 275         res = tipc_register_media(TIPC_MEDIA_TYPE_ETH, "eth",
 276                                   enable_bearer, disable_bearer, send_msg,
 277                                   eth_addr2str, &bcast_addr, ETH_LINK_PRIORITY,
 278                                   ETH_LINK_TOLERANCE, ETH_LINK_WINDOW);
 279         if (res)
 280                 return res;
 281
 282         notifier.notifier_call = &recv_notification;
 283         notifier.priority = 0;
 284         res = register_netdevice_notifier(&notifier);
 285         if (!res)
 286                 eth_started = 1;
 287         return res;
 288 }
 289
 290 /**
 291  * tipc_eth_media_stop - deactivate Ethernet bearer support
 292  */
 293
 294 void tipc_eth_media_stop(void)
 295 {
 296         int i;
 297
 298         if (!eth_started)
 299                 return;
 300
 301         unregister_netdevice_notifier(&notifier);
 302         for (i = 0; i < MAX_ETH_BEARERS ; i++) {
 303                 if (eth_bearers[i].bearer) {
 304                         eth_bearers[i].bearer->blocked = 1;
 305                         eth_bearers[i].bearer = NULL;
 306                 }
 307                 if (eth_bearers[i].dev) {
 308                         dev_remove_pack(&eth_bearers[i].tipc_packet_type);
 309                         dev_put(eth_bearers[i].dev);
 310                 }
 311         }
 312         memset(&eth_bearers, 0, sizeof(eth_bearers));
 313         eth_started = 0;
 314 }