linux/net/tipc/eth_media.c
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   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
  55struct eth_bearer {
  56        struct tipc_bearer *bearer;
  57        struct net_device *dev;
  58        struct packet_type tipc_packet_type;
  59};
  60
  61static struct eth_bearer eth_bearers[MAX_ETH_BEARERS];
  62static int eth_started = 0;
  63static struct notifier_block notifier;
  64
  65/**
  66 * send_msg - send a TIPC message out over an Ethernet interface
  67 */
  68
  69static 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
  98static 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
 128static 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
 182static 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
 194static 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
 243static 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
 261int 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
 293void 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}
 314