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) 2005-2008, 2011, 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 "core.h"
  38#include "bearer.h"
  39
  40#define MAX_ETH_BEARERS         MAX_BEARERS
  41
  42#define ETH_ADDR_OFFSET 4       /* message header offset of MAC address */
  43
  44/**
  45 * struct eth_bearer - Ethernet bearer data structure
  46 * @bearer: ptr to associated "generic" bearer structure
  47 * @dev: ptr to associated Ethernet network device
  48 * @tipc_packet_type: used in binding TIPC to Ethernet driver
  49 * @cleanup: work item used when disabling bearer
  50 */
  51
  52struct eth_bearer {
  53        struct tipc_bearer *bearer;
  54        struct net_device *dev;
  55        struct packet_type tipc_packet_type;
  56        struct work_struct cleanup;
  57};
  58
  59static struct tipc_media eth_media_info;
  60static struct eth_bearer eth_bearers[MAX_ETH_BEARERS];
  61static int eth_started;
  62static struct notifier_block notifier;
  63
  64/**
  65 * eth_media_addr_set - initialize Ethernet media address structure
  66 *
  67 * Media-dependent "value" field stores MAC address in first 6 bytes
  68 * and zeroes out the remaining bytes.
  69 */
  70
  71static void eth_media_addr_set(struct tipc_media_addr *a, char *mac)
  72{
  73        memcpy(a->value, mac, ETH_ALEN);
  74        memset(a->value + ETH_ALEN, 0, sizeof(a->value) - ETH_ALEN);
  75        a->media_id = TIPC_MEDIA_TYPE_ETH;
  76        a->broadcast = !memcmp(mac, eth_media_info.bcast_addr.value, ETH_ALEN);
  77}
  78
  79/**
  80 * send_msg - send a TIPC message out over an Ethernet interface
  81 */
  82
  83static int send_msg(struct sk_buff *buf, struct tipc_bearer *tb_ptr,
  84                    struct tipc_media_addr *dest)
  85{
  86        struct sk_buff *clone;
  87        struct net_device *dev;
  88        int delta;
  89
  90        clone = skb_clone(buf, GFP_ATOMIC);
  91        if (!clone)
  92                return 0;
  93
  94        dev = ((struct eth_bearer *)(tb_ptr->usr_handle))->dev;
  95        delta = dev->hard_header_len - skb_headroom(buf);
  96
  97        if ((delta > 0) &&
  98            pskb_expand_head(clone, SKB_DATA_ALIGN(delta), 0, GFP_ATOMIC)) {
  99                kfree_skb(clone);
 100                return 0;
 101        }
 102
 103        skb_reset_network_header(clone);
 104        clone->dev = dev;
 105        dev_hard_header(clone, dev, ETH_P_TIPC, dest->value,
 106                        dev->dev_addr, clone->len);
 107        dev_queue_xmit(clone);
 108        return 0;
 109}
 110
 111/**
 112 * recv_msg - handle incoming TIPC message from an Ethernet interface
 113 *
 114 * Accept only packets explicitly sent to this node, or broadcast packets;
 115 * ignores packets sent using Ethernet multicast, and traffic sent to other
 116 * nodes (which can happen if interface is running in promiscuous mode).
 117 */
 118
 119static int recv_msg(struct sk_buff *buf, struct net_device *dev,
 120                    struct packet_type *pt, struct net_device *orig_dev)
 121{
 122        struct eth_bearer *eb_ptr = (struct eth_bearer *)pt->af_packet_priv;
 123
 124        if (!net_eq(dev_net(dev), &init_net)) {
 125                kfree_skb(buf);
 126                return 0;
 127        }
 128
 129        if (likely(eb_ptr->bearer)) {
 130                if (likely(buf->pkt_type <= PACKET_BROADCAST)) {
 131                        buf->next = NULL;
 132                        tipc_recv_msg(buf, eb_ptr->bearer);
 133                        return 0;
 134                }
 135        }
 136        kfree_skb(buf);
 137        return 0;
 138}
 139
 140/**
 141 * enable_bearer - attach TIPC bearer to an Ethernet interface
 142 */
 143
 144static int enable_bearer(struct tipc_bearer *tb_ptr)
 145{
 146        struct net_device *dev = NULL;
 147        struct net_device *pdev = NULL;
 148        struct eth_bearer *eb_ptr = &eth_bearers[0];
 149        struct eth_bearer *stop = &eth_bearers[MAX_ETH_BEARERS];
 150        char *driver_name = strchr((const char *)tb_ptr->name, ':') + 1;
 151        int pending_dev = 0;
 152
 153        /* Find unused Ethernet bearer structure */
 154
 155        while (eb_ptr->dev) {
 156                if (!eb_ptr->bearer)
 157                        pending_dev++;
 158                if (++eb_ptr == stop)
 159                        return pending_dev ? -EAGAIN : -EDQUOT;
 160        }
 161
 162        /* Find device with specified name */
 163
 164        read_lock(&dev_base_lock);
 165        for_each_netdev(&init_net, pdev) {
 166                if (!strncmp(pdev->name, driver_name, IFNAMSIZ)) {
 167                        dev = pdev;
 168                        dev_hold(dev);
 169                        break;
 170                }
 171        }
 172        read_unlock(&dev_base_lock);
 173        if (!dev)
 174                return -ENODEV;
 175
 176        /* Create Ethernet bearer for device */
 177
 178        eb_ptr->dev = dev;
 179        eb_ptr->tipc_packet_type.type = htons(ETH_P_TIPC);
 180        eb_ptr->tipc_packet_type.dev = dev;
 181        eb_ptr->tipc_packet_type.func = recv_msg;
 182        eb_ptr->tipc_packet_type.af_packet_priv = eb_ptr;
 183        INIT_LIST_HEAD(&(eb_ptr->tipc_packet_type.list));
 184        dev_add_pack(&eb_ptr->tipc_packet_type);
 185
 186        /* Associate TIPC bearer with Ethernet bearer */
 187
 188        eb_ptr->bearer = tb_ptr;
 189        tb_ptr->usr_handle = (void *)eb_ptr;
 190        tb_ptr->mtu = dev->mtu;
 191        tb_ptr->blocked = 0;
 192        eth_media_addr_set(&tb_ptr->addr, (char *)dev->dev_addr);
 193        return 0;
 194}
 195
 196/**
 197 * cleanup_bearer - break association between Ethernet bearer and interface
 198 *
 199 * This routine must be invoked from a work queue because it can sleep.
 200 */
 201
 202static void cleanup_bearer(struct work_struct *work)
 203{
 204        struct eth_bearer *eb_ptr =
 205                container_of(work, struct eth_bearer, cleanup);
 206
 207        dev_remove_pack(&eb_ptr->tipc_packet_type);
 208        dev_put(eb_ptr->dev);
 209        eb_ptr->dev = NULL;
 210}
 211
 212/**
 213 * disable_bearer - detach TIPC bearer from an Ethernet interface
 214 *
 215 * Mark Ethernet bearer as inactive so that incoming buffers are thrown away,
 216 * then get worker thread to complete bearer cleanup.  (Can't do cleanup
 217 * here because cleanup code needs to sleep and caller holds spinlocks.)
 218 */
 219
 220static void disable_bearer(struct tipc_bearer *tb_ptr)
 221{
 222        struct eth_bearer *eb_ptr = (struct eth_bearer *)tb_ptr->usr_handle;
 223
 224        eb_ptr->bearer = NULL;
 225        INIT_WORK(&eb_ptr->cleanup, cleanup_bearer);
 226        schedule_work(&eb_ptr->cleanup);
 227}
 228
 229/**
 230 * recv_notification - handle device updates from OS
 231 *
 232 * Change the state of the Ethernet bearer (if any) associated with the
 233 * specified device.
 234 */
 235
 236static int recv_notification(struct notifier_block *nb, unsigned long evt,
 237                             void *dv)
 238{
 239        struct net_device *dev = (struct net_device *)dv;
 240        struct eth_bearer *eb_ptr = &eth_bearers[0];
 241        struct eth_bearer *stop = &eth_bearers[MAX_ETH_BEARERS];
 242
 243        if (!net_eq(dev_net(dev), &init_net))
 244                return NOTIFY_DONE;
 245
 246        while ((eb_ptr->dev != dev)) {
 247                if (++eb_ptr == stop)
 248                        return NOTIFY_DONE;     /* couldn't find device */
 249        }
 250        if (!eb_ptr->bearer)
 251                return NOTIFY_DONE;             /* bearer had been disabled */
 252
 253        eb_ptr->bearer->mtu = dev->mtu;
 254
 255        switch (evt) {
 256        case NETDEV_CHANGE:
 257                if (netif_carrier_ok(dev))
 258                        tipc_continue(eb_ptr->bearer);
 259                else
 260                        tipc_block_bearer(eb_ptr->bearer->name);
 261                break;
 262        case NETDEV_UP:
 263                tipc_continue(eb_ptr->bearer);
 264                break;
 265        case NETDEV_DOWN:
 266                tipc_block_bearer(eb_ptr->bearer->name);
 267                break;
 268        case NETDEV_CHANGEMTU:
 269        case NETDEV_CHANGEADDR:
 270                tipc_block_bearer(eb_ptr->bearer->name);
 271                tipc_continue(eb_ptr->bearer);
 272                break;
 273        case NETDEV_UNREGISTER:
 274        case NETDEV_CHANGENAME:
 275                tipc_disable_bearer(eb_ptr->bearer->name);
 276                break;
 277        }
 278        return NOTIFY_OK;
 279}
 280
 281/**
 282 * eth_addr2str - convert Ethernet address to string
 283 */
 284
 285static int eth_addr2str(struct tipc_media_addr *a, char *str_buf, int str_size)
 286{
 287        if (str_size < 18)      /* 18 = strlen("aa:bb:cc:dd:ee:ff\0") */
 288                return 1;
 289
 290        sprintf(str_buf, "%pM", a->value);
 291        return 0;
 292}
 293
 294/**
 295 * eth_str2addr - convert string to Ethernet address
 296 */
 297
 298static int eth_str2addr(struct tipc_media_addr *a, char *str_buf)
 299{
 300        char mac[ETH_ALEN];
 301        int r;
 302
 303        r = sscanf(str_buf, "%02x:%02x:%02x:%02x:%02x:%02x",
 304                       (u32 *)&mac[0], (u32 *)&mac[1], (u32 *)&mac[2],
 305                       (u32 *)&mac[3], (u32 *)&mac[4], (u32 *)&mac[5]);
 306
 307        if (r != ETH_ALEN)
 308                return 1;
 309
 310        eth_media_addr_set(a, mac);
 311        return 0;
 312}
 313
 314/**
 315 * eth_str2addr - convert Ethernet address format to message header format
 316 */
 317
 318static int eth_addr2msg(struct tipc_media_addr *a, char *msg_area)
 319{
 320        memset(msg_area, 0, TIPC_MEDIA_ADDR_SIZE);
 321        msg_area[TIPC_MEDIA_TYPE_OFFSET] = TIPC_MEDIA_TYPE_ETH;
 322        memcpy(msg_area + ETH_ADDR_OFFSET, a->value, ETH_ALEN);
 323        return 0;
 324}
 325
 326/**
 327 * eth_str2addr - convert message header address format to Ethernet format
 328 */
 329
 330static int eth_msg2addr(struct tipc_media_addr *a, char *msg_area)
 331{
 332        if (msg_area[TIPC_MEDIA_TYPE_OFFSET] != TIPC_MEDIA_TYPE_ETH)
 333                return 1;
 334
 335        eth_media_addr_set(a, msg_area + ETH_ADDR_OFFSET);
 336        return 0;
 337}
 338
 339/*
 340 * Ethernet media registration info
 341 */
 342
 343static struct tipc_media eth_media_info = {
 344        .send_msg       = send_msg,
 345        .enable_bearer  = enable_bearer,
 346        .disable_bearer = disable_bearer,
 347        .addr2str       = eth_addr2str,
 348        .str2addr       = eth_str2addr,
 349        .addr2msg       = eth_addr2msg,
 350        .msg2addr       = eth_msg2addr,
 351        .bcast_addr     = { { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff },
 352                            TIPC_MEDIA_TYPE_ETH, 1 },
 353        .priority       = TIPC_DEF_LINK_PRI,
 354        .tolerance      = TIPC_DEF_LINK_TOL,
 355        .window         = TIPC_DEF_LINK_WIN,
 356        .type_id        = TIPC_MEDIA_TYPE_ETH,
 357        .name           = "eth"
 358};
 359
 360/**
 361 * tipc_eth_media_start - activate Ethernet bearer support
 362 *
 363 * Register Ethernet media type with TIPC bearer code.  Also register
 364 * with OS for notifications about device state changes.
 365 */
 366
 367int tipc_eth_media_start(void)
 368{
 369        int res;
 370
 371        if (eth_started)
 372                return -EINVAL;
 373
 374        res = tipc_register_media(&eth_media_info);
 375        if (res)
 376                return res;
 377
 378        notifier.notifier_call = &recv_notification;
 379        notifier.priority = 0;
 380        res = register_netdevice_notifier(&notifier);
 381        if (!res)
 382                eth_started = 1;
 383        return res;
 384}
 385
 386/**
 387 * tipc_eth_media_stop - deactivate Ethernet bearer support
 388 */
 389
 390void tipc_eth_media_stop(void)
 391{
 392        if (!eth_started)
 393                return;
 394
 395        flush_scheduled_work();
 396        unregister_netdevice_notifier(&notifier);
 397        eth_started = 0;
 398}
 399