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 <net/net_namespace.h>
42
43#define MAX_ETH_BEARERS 2
44#define ETH_LINK_PRIORITY TIPC_DEF_LINK_PRI
45#define ETH_LINK_TOLERANCE TIPC_DEF_LINK_TOL
46#define ETH_LINK_WINDOW TIPC_DEF_LINK_WIN
47
48/**
49 * struct eth_bearer - Ethernet bearer data structure
50 * @bearer: ptr to associated "generic" bearer structure
51 * @dev: ptr to associated Ethernet network device
52 * @tipc_packet_type: used in binding TIPC to Ethernet driver
53 */
54
55struct eth_bearer {
56    struct tipc_bearer *bearer;
57    struct net_device *dev;
58    struct packet_type tipc_packet_type;
59};
60
61static struct eth_bearer eth_bearers[MAX_ETH_BEARERS];
62static int eth_started = 0;
63static struct notifier_block notifier;
64
65/**
66 * send_msg - send a TIPC message out over an Ethernet interface
67 */
68
69static int send_msg(struct sk_buff *buf, struct tipc_bearer *tb_ptr,
70            struct tipc_media_addr *dest)
71{
72    struct sk_buff *clone;
73    struct net_device *dev;
74
75    clone = skb_clone(buf, GFP_ATOMIC);
76    if (clone) {
77        skb_reset_network_header(clone);
78        dev = ((struct eth_bearer *)(tb_ptr->usr_handle))->dev;
79        clone->dev = dev;
80        dev_hard_header(clone, dev, ETH_P_TIPC,
81                 &dest->dev_addr.eth_addr,
82                 dev->dev_addr, clone->len);
83        dev_queue_xmit(clone);
84    }
85    return 0;
86}
87
88/**
89 * recv_msg - handle incoming TIPC message from an Ethernet interface
90 *
91 * Accept only packets explicitly sent to this node, or broadcast packets;
92 * ignores packets sent using Ethernet multicast, and traffic sent to other
93 * nodes (which can happen if interface is running in promiscuous mode).
94 * Routine truncates any Ethernet padding/CRC appended to the message,
95 * and ensures message size matches actual length
96 */
97
98static int recv_msg(struct sk_buff *buf, struct net_device *dev,
99            struct packet_type *pt, struct net_device *orig_dev)
100{
101    struct eth_bearer *eb_ptr = (struct eth_bearer *)pt->af_packet_priv;
102    u32 size;
103
104    if (!net_eq(dev_net(dev), &init_net)) {
105        kfree_skb(buf);
106        return 0;
107    }
108
109    if (likely(eb_ptr->bearer)) {
110        if (likely(buf->pkt_type <= PACKET_BROADCAST)) {
111            size = msg_size((struct tipc_msg *)buf->data);
112            skb_trim(buf, size);
113            if (likely(buf->len == size)) {
114                buf->next = NULL;
115                tipc_recv_msg(buf, eb_ptr->bearer);
116                return 0;
117            }
118        }
119    }
120    kfree_skb(buf);
121    return 0;
122}
123
124/**
125 * enable_bearer - attach TIPC bearer to an Ethernet interface
126 */
127
128static int enable_bearer(struct tipc_bearer *tb_ptr)
129{
130    struct net_device *dev = NULL;
131    struct net_device *pdev = NULL;
132    struct eth_bearer *eb_ptr = &eth_bearers[0];
133    struct eth_bearer *stop = &eth_bearers[MAX_ETH_BEARERS];
134    char *driver_name = strchr((const char *)tb_ptr->name, ':') + 1;
135
136    /* Find device with specified name */
137
138    for_each_netdev(&init_net, pdev){
139        if (!strncmp(pdev->name, driver_name, IFNAMSIZ)) {
140            dev = pdev;
141            break;
142        }
143    }
144    if (!dev)
145        return -ENODEV;
146
147    /* Find Ethernet bearer for device (or create one) */
148
149    for (;(eb_ptr != stop) && eb_ptr->dev && (eb_ptr->dev != dev); eb_ptr++);
150    if (eb_ptr == stop)
151        return -EDQUOT;
152    if (!eb_ptr->dev) {
153        eb_ptr->dev = dev;
154        eb_ptr->tipc_packet_type.type = htons(ETH_P_TIPC);
155        eb_ptr->tipc_packet_type.dev = dev;
156        eb_ptr->tipc_packet_type.func = recv_msg;
157        eb_ptr->tipc_packet_type.af_packet_priv = eb_ptr;
158        INIT_LIST_HEAD(&(eb_ptr->tipc_packet_type.list));
159        dev_hold(dev);
160        dev_add_pack(&eb_ptr->tipc_packet_type);
161    }
162
163    /* Associate TIPC bearer with Ethernet bearer */
164
165    eb_ptr->bearer = tb_ptr;
166    tb_ptr->usr_handle = (void *)eb_ptr;
167    tb_ptr->mtu = dev->mtu;
168    tb_ptr->blocked = 0;
169    tb_ptr->addr.type = htonl(TIPC_MEDIA_TYPE_ETH);
170    memcpy(&tb_ptr->addr.dev_addr, dev->dev_addr, ETH_ALEN);
171    return 0;
172}
173
174/**
175 * disable_bearer - detach TIPC bearer from an Ethernet interface
176 *
177 * We really should do dev_remove_pack() here, but this function can not be
178 * called at tasklet level. => Use eth_bearer->bearer as a flag to throw away
179 * incoming buffers, & postpone dev_remove_pack() to eth_media_stop() on exit.
180 */
181
182static void disable_bearer(struct tipc_bearer *tb_ptr)
183{
184    ((struct eth_bearer *)tb_ptr->usr_handle)->bearer = NULL;
185}
186
187/**
188 * recv_notification - handle device updates from OS
189 *
190 * Change the state of the Ethernet bearer (if any) associated with the
191 * specified device.
192 */
193
194static int recv_notification(struct notifier_block *nb, unsigned long evt,
195                 void *dv)
196{
197    struct net_device *dev = (struct net_device *)dv;
198    struct eth_bearer *eb_ptr = &eth_bearers[0];
199    struct eth_bearer *stop = &eth_bearers[MAX_ETH_BEARERS];
200
201    if (!net_eq(dev_net(dev), &init_net))
202        return NOTIFY_DONE;
203
204    while ((eb_ptr->dev != dev)) {
205        if (++eb_ptr == stop)
206            return NOTIFY_DONE; /* couldn't find device */
207    }
208    if (!eb_ptr->bearer)
209        return NOTIFY_DONE; /* bearer had been disabled */
210
211    eb_ptr->bearer->mtu = dev->mtu;
212
213    switch (evt) {
214    case NETDEV_CHANGE:
215        if (netif_carrier_ok(dev))
216            tipc_continue(eb_ptr->bearer);
217        else
218            tipc_block_bearer(eb_ptr->bearer->name);
219        break;
220    case NETDEV_UP:
221        tipc_continue(eb_ptr->bearer);
222        break;
223    case NETDEV_DOWN:
224        tipc_block_bearer(eb_ptr->bearer->name);
225        break;
226    case NETDEV_CHANGEMTU:
227    case NETDEV_CHANGEADDR:
228        tipc_block_bearer(eb_ptr->bearer->name);
229        tipc_continue(eb_ptr->bearer);
230        break;
231    case NETDEV_UNREGISTER:
232    case NETDEV_CHANGENAME:
233        tipc_disable_bearer(eb_ptr->bearer->name);
234        break;
235    }
236    return NOTIFY_OK;
237}
238
239/**
240 * eth_addr2str - convert Ethernet address to string
241 */
242
243static char *eth_addr2str(struct tipc_media_addr *a, char *str_buf, int str_size)
244{
245    unchar *addr = (unchar *)&a->dev_addr;
246
247    if (str_size < 18)
248        *str_buf = '\0';
249    else
250        sprintf(str_buf, "%pM", addr);
251    return str_buf;
252}
253
254/**
255 * tipc_eth_media_start - activate Ethernet bearer support
256 *
257 * Register Ethernet media type with TIPC bearer code. Also register
258 * with OS for notifications about device state changes.
259 */
260
261int tipc_eth_media_start(void)
262{
263    struct tipc_media_addr bcast_addr;
264    int res;
265
266    if (eth_started)
267        return -EINVAL;
268
269    bcast_addr.type = htonl(TIPC_MEDIA_TYPE_ETH);
270    memset(&bcast_addr.dev_addr, 0xff, ETH_ALEN);
271
272    memset(eth_bearers, 0, sizeof(eth_bearers));
273
274    res = tipc_register_media(TIPC_MEDIA_TYPE_ETH, "eth",
275                  enable_bearer, disable_bearer, send_msg,
276                  eth_addr2str, &bcast_addr, ETH_LINK_PRIORITY,
277                  ETH_LINK_TOLERANCE, ETH_LINK_WINDOW);
278    if (res)
279        return res;
280
281    notifier.notifier_call = &recv_notification;
282    notifier.priority = 0;
283    res = register_netdevice_notifier(&notifier);
284    if (!res)
285        eth_started = 1;
286    return res;
287}
288
289/**
290 * tipc_eth_media_stop - deactivate Ethernet bearer support
291 */
292
293void tipc_eth_media_stop(void)
294{
295    int i;
296
297    if (!eth_started)
298        return;
299
300    unregister_netdevice_notifier(&notifier);
301    for (i = 0; i < MAX_ETH_BEARERS ; i++) {
302        if (eth_bearers[i].bearer) {
303            eth_bearers[i].bearer->blocked = 1;
304            eth_bearers[i].bearer = NULL;
305        }
306        if (eth_bearers[i].dev) {
307            dev_remove_pack(&eth_bearers[i].tipc_packet_type);
308            dev_put(eth_bearers[i].dev);
309        }
310    }
311    memset(&eth_bearers, 0, sizeof(eth_bearers));
312    eth_started = 0;
313}
314

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