Root/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) 2005-2007, 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

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