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