summaryrefslogtreecommitdiffstats
path: root/net/hsr/hsr_slave.c
blob: 23817d0b765b68dff83b143b9b21091cffb1865b (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
/* Copyright 2011-2014 Autronica Fire and Security AS
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the Free
 * Software Foundation; either version 2 of the License, or (at your option)
 * any later version.
 *
 * Author(s):
 *	2011-2014 Arvid Brodin, arvid.brodin@alten.se
 */

#include "hsr_slave.h"
#include <linux/etherdevice.h>
#include <linux/if_arp.h>
#include "hsr_main.h"
#include "hsr_device.h"
#include "hsr_framereg.h"


static int hsr_check_dev_ok(struct net_device *dev)
{
	/* Don't allow HSR on non-ethernet like devices */
	if ((dev->flags & IFF_LOOPBACK) || (dev->type != ARPHRD_ETHER) ||
	    (dev->addr_len != ETH_ALEN)) {
		netdev_info(dev, "Cannot use loopback or non-ethernet device as HSR slave.\n");
		return -EINVAL;
	}

	/* Don't allow enslaving hsr devices */
	if (is_hsr_master(dev)) {
		netdev_info(dev, "Cannot create trees of HSR devices.\n");
		return -EINVAL;
	}

	if (hsr_port_exists(dev)) {
		netdev_info(dev, "This device is already a HSR slave.\n");
		return -EINVAL;
	}

	if (dev->priv_flags & IFF_802_1Q_VLAN) {
		netdev_info(dev, "HSR on top of VLAN is not yet supported in this driver.\n");
		return -EINVAL;
	}

	/* HSR over bonded devices has not been tested, but I'm not sure it
	 * won't work...
	 */

	return 0;
}


static struct sk_buff *hsr_pull_tag(struct sk_buff *skb)
{
	struct hsr_tag *hsr_tag;
	struct sk_buff *skb2;

	skb2 = skb_share_check(skb, GFP_ATOMIC);
	if (unlikely(!skb2))
		goto err_free;
	skb = skb2;

	if (unlikely(!pskb_may_pull(skb, HSR_HLEN)))
		goto err_free;

	hsr_tag = (struct hsr_tag *) skb->data;
	skb->protocol = hsr_tag->encap_proto;
	skb_pull(skb, HSR_HLEN);

	return skb;

err_free:
	kfree_skb(skb);
	return NULL;
}


/* The uses I can see for these HSR supervision frames are:
 * 1) Use the frames that are sent after node initialization ("HSR_TLV.Type =
 *    22") to reset any sequence_nr counters belonging to that node. Useful if
 *    the other node's counter has been reset for some reason.
 *    --
 *    Or not - resetting the counter and bridging the frame would create a
 *    loop, unfortunately.
 *
 * 2) Use the LifeCheck frames to detect ring breaks. I.e. if no LifeCheck
 *    frame is received from a particular node, we know something is wrong.
 *    We just register these (as with normal frames) and throw them away.
 *
 * 3) Allow different MAC addresses for the two slave interfaces, using the
 *    MacAddressA field.
 */
static bool is_supervision_frame(struct hsr_priv *hsr, struct sk_buff *skb)
{
	struct hsr_sup_tag *hsr_stag;

	if (!ether_addr_equal(eth_hdr(skb)->h_dest,
			      hsr->sup_multicast_addr))
		return false;

	hsr_stag = (struct hsr_sup_tag *) skb->data;
	if (get_hsr_stag_path(hsr_stag) != 0x0f)
		return false;
	if ((hsr_stag->HSR_TLV_Type != HSR_TLV_ANNOUNCE) &&
	    (hsr_stag->HSR_TLV_Type != HSR_TLV_LIFE_CHECK))
		return false;
	if (hsr_stag->HSR_TLV_Length != 12)
		return false;

	return true;
}


/* Implementation somewhat according to IEC-62439-3, p. 43
 */
rx_handler_result_t hsr_handle_frame(struct sk_buff **pskb)
{
	struct sk_buff *skb = *pskb;
	struct hsr_port *port, *other_port, *master;
	struct hsr_priv *hsr;
	struct hsr_node *node;
	bool deliver_to_self;
	struct sk_buff *skb_deliver;
	bool dup_out;
	int ret;

	if (eth_hdr(skb)->h_proto != htons(ETH_P_PRP))
		return RX_HANDLER_PASS;

	rcu_read_lock(); /* ports & node */

	port = hsr_port_get_rcu(skb->dev);
	hsr = port->hsr;
	master = hsr_port_get_hsr(hsr, HSR_PT_MASTER);

	node = hsr_find_node(&hsr->self_node_db, skb);
	if (node) {
		/* Always kill frames sent by ourselves */
		kfree_skb(skb);
		ret = RX_HANDLER_CONSUMED;
		goto finish;
	}

	/* Is this frame a candidate for local reception? */
	deliver_to_self = false;
	if ((skb->pkt_type == PACKET_HOST) ||
	    (skb->pkt_type == PACKET_MULTICAST) ||
	    (skb->pkt_type == PACKET_BROADCAST))
		deliver_to_self = true;
	else if (ether_addr_equal(eth_hdr(skb)->h_dest,
				  master->dev->dev_addr)) {
		skb->pkt_type = PACKET_HOST;
		deliver_to_self = true;
	}

	node = hsr_find_node(&hsr->node_db, skb);

	if (is_supervision_frame(hsr, skb)) {
		skb_pull(skb, sizeof(struct hsr_sup_tag));
		node = hsr_merge_node(node, skb, port);
		if (!node) {
			kfree_skb(skb);
			master->dev->stats.rx_dropped++;
			ret = RX_HANDLER_CONSUMED;
			goto finish;
		}
		skb_push(skb, sizeof(struct hsr_sup_tag));
		deliver_to_self = false;
	}

	if (!node) {
		/* Source node unknown; this might be a HSR frame from
		 * another net (different multicast address). Ignore it.
		 */
		kfree_skb(skb);
		ret = RX_HANDLER_CONSUMED;
		goto finish;
	}

	if (port->type == HSR_PT_SLAVE_A)
		other_port = hsr_port_get_hsr(hsr, HSR_PT_SLAVE_B);
	else
		other_port = hsr_port_get_hsr(hsr, HSR_PT_SLAVE_A);

	/* Register ALL incoming frames as outgoing through the other interface.
	 * This allows us to register frames as incoming only if they are valid
	 * for the receiving interface, without using a specific counter for
	 * incoming frames.
	 */
	if (other_port)
		dup_out = hsr_register_frame_out(node, other_port, skb);
	else
		dup_out = 0;
	if (!dup_out)
		hsr_register_frame_in(node, port);

	/* Forward this frame? */
	if (dup_out || (skb->pkt_type == PACKET_HOST))
		other_port = NULL;

	if (hsr_register_frame_out(node, master, skb))
		deliver_to_self = false;

	if (!deliver_to_self && !other_port) {
		kfree_skb(skb);
		/* Circulated frame; silently remove it. */
		ret = RX_HANDLER_CONSUMED;
		goto finish;
	}

	skb_deliver = skb;
	if (deliver_to_self && other_port) {
		/* skb_clone() is not enough since we will strip the hsr tag
		 * and do address substitution below
		 */
		skb_deliver = pskb_copy(skb, GFP_ATOMIC);
		if (!skb_deliver) {
			deliver_to_self = false;
			master->dev->stats.rx_dropped++;
		}
	}

	if (deliver_to_self) {
		bool multicast_frame;

		skb_deliver = hsr_pull_tag(skb_deliver);
		if (!skb_deliver) {
			master->dev->stats.rx_dropped++;
			goto forward;
		}
#if !defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS)
		/* Move everything in the header that is after the HSR tag,
		 * to work around alignment problems caused by the 6-byte HSR
		 * tag. In practice, this removes/overwrites the HSR tag in
		 * the header and restores a "standard" packet.
		 */
		memmove(skb_deliver->data - HSR_HLEN, skb_deliver->data,
			skb_headlen(skb_deliver));

		/* Adjust skb members so they correspond with the move above.
		 * This cannot possibly underflow skb->data since hsr_pull_tag()
		 * above succeeded.
		 * At this point in the protocol stack, the transport and
		 * network headers have not been set yet, and we haven't touched
		 * the mac header nor the head. So we only need to adjust data
		 * and tail:
		 */
		skb_deliver->data -= HSR_HLEN;
		skb_deliver->tail -= HSR_HLEN;
#endif
		skb_deliver->dev = master->dev;
		hsr_addr_subst_source(hsr, skb_deliver);
		multicast_frame = (skb_deliver->pkt_type == PACKET_MULTICAST);
		ret = netif_rx(skb_deliver);
		if (ret == NET_RX_DROP) {
			master->dev->stats.rx_dropped++;
		} else {
			master->dev->stats.rx_packets++;
			master->dev->stats.rx_bytes += skb->len;
			if (multicast_frame)
				master->dev->stats.multicast++;
		}
	}

forward:
	if (other_port) {
		skb_push(skb, ETH_HLEN);
		skb->dev = other_port->dev;
		dev_queue_xmit(skb);
	}

	ret = RX_HANDLER_CONSUMED;

finish:
	rcu_read_unlock();
	return ret;
}

/* Setup device to be added to the HSR bridge. */
static int hsr_portdev_setup(struct net_device *dev, struct hsr_port *port)
{
	int res;

	dev_hold(dev);
	res = dev_set_promiscuity(dev, 1);
	if (res)
		goto fail_promiscuity;
	res = netdev_rx_handler_register(dev, hsr_handle_frame, port);
	if (res)
		goto fail_rx_handler;
	dev_disable_lro(dev);

	/* FIXME:
	 * What does net device "adjacency" mean? Should we do
	 * res = netdev_master_upper_dev_link(port->dev, port->hsr->dev); ?
	 */

	return 0;

fail_rx_handler:
	dev_set_promiscuity(dev, -1);
fail_promiscuity:
	dev_put(dev);

	return res;
}

int hsr_add_port(struct hsr_priv *hsr, struct net_device *dev,
		 enum hsr_port_type type)
{
	struct hsr_port *port, *master;
	int res;

	if (type != HSR_PT_MASTER) {
		res = hsr_check_dev_ok(dev);
		if (res)
			return res;
	}

	port = hsr_port_get_hsr(hsr, type);
	if (port != NULL)
		return -EBUSY;	/* This port already exists */

	port = kzalloc(sizeof(*port), GFP_KERNEL);
	if (port == NULL)
		return -ENOMEM;

	if (type != HSR_PT_MASTER) {
		res = hsr_portdev_setup(dev, port);
		if (res)
			goto fail_dev_setup;
	}

	port->hsr = hsr;
	port->dev = dev;
	port->type = type;

	list_add_tail_rcu(&port->port_list, &hsr->ports);
	synchronize_rcu();

	master = hsr_port_get_hsr(hsr, HSR_PT_MASTER);

	/* Set required header length */
	if (dev->hard_header_len + HSR_HLEN > master->dev->hard_header_len)
		master->dev->hard_header_len = dev->hard_header_len + HSR_HLEN;

	netdev_update_features(master->dev);
	dev_set_mtu(master->dev, hsr_get_max_mtu(hsr));

	return 0;

fail_dev_setup:
	kfree(port);
	return res;
}

void hsr_del_port(struct hsr_port *port)
{
	struct hsr_priv *hsr;
	struct hsr_port *master;

	hsr = port->hsr;
	master = hsr_port_get_hsr(hsr, HSR_PT_MASTER);
	list_del_rcu(&port->port_list);

	if (port != master) {
		netdev_update_features(master->dev);
		dev_set_mtu(master->dev, hsr_get_max_mtu(hsr));
		netdev_rx_handler_unregister(port->dev);
		dev_set_promiscuity(port->dev, -1);
	}

	/* FIXME?
	 * netdev_upper_dev_unlink(port->dev, port->hsr->dev);
	 */

	synchronize_rcu();
	dev_put(port->dev);
}