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