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 <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
  56struct eth_bearer {
  57        struct tipc_bearer *bearer;
  58        struct net_device *dev;
  59        struct packet_type tipc_packet_type;
  60};
  61
  62static struct eth_bearer eth_bearers[MAX_ETH_BEARERS];
  63static int eth_started = 0;
  64static struct notifier_block notifier;
  65
  66/**
  67 * send_msg - send a TIPC message out over an Ethernet interface
  68 */
  69
  70static 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
  99static 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
 129static 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
 183static 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
 195static 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
 244static 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
 262int 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
 294void 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}
 315