xref: /openbmc/linux/net/hsr/hsr_framereg.c (revision 39cc316f)
1 // SPDX-License-Identifier: GPL-2.0
2 /* Copyright 2011-2014 Autronica Fire and Security AS
3  *
4  * Author(s):
5  *	2011-2014 Arvid Brodin, arvid.brodin@alten.se
6  *
7  * The HSR spec says never to forward the same frame twice on the same
8  * interface. A frame is identified by its source MAC address and its HSR
9  * sequence number. This code keeps track of senders and their sequence numbers
10  * to allow filtering of duplicate frames, and to detect HSR ring errors.
11  * Same code handles filtering of duplicates for PRP as well.
12  */
13 
14 #include <linux/if_ether.h>
15 #include <linux/etherdevice.h>
16 #include <linux/slab.h>
17 #include <linux/rculist.h>
18 #include "hsr_main.h"
19 #include "hsr_framereg.h"
20 #include "hsr_netlink.h"
21 
22 /* seq_nr_after(a, b) - return true if a is after (higher in sequence than) b,
23  * false otherwise.
24  */
seq_nr_after(u16 a,u16 b)25 static bool seq_nr_after(u16 a, u16 b)
26 {
27 	/* Remove inconsistency where
28 	 * seq_nr_after(a, b) == seq_nr_before(a, b)
29 	 */
30 	if ((int)b - a == 32768)
31 		return false;
32 
33 	return (((s16)(b - a)) < 0);
34 }
35 
36 #define seq_nr_before(a, b)		seq_nr_after((b), (a))
37 #define seq_nr_before_or_eq(a, b)	(!seq_nr_after((a), (b)))
38 
hsr_addr_is_self(struct hsr_priv * hsr,unsigned char * addr)39 bool hsr_addr_is_self(struct hsr_priv *hsr, unsigned char *addr)
40 {
41 	struct hsr_self_node *sn;
42 	bool ret = false;
43 
44 	rcu_read_lock();
45 	sn = rcu_dereference(hsr->self_node);
46 	if (!sn) {
47 		WARN_ONCE(1, "HSR: No self node\n");
48 		goto out;
49 	}
50 
51 	if (ether_addr_equal(addr, sn->macaddress_A) ||
52 	    ether_addr_equal(addr, sn->macaddress_B))
53 		ret = true;
54 out:
55 	rcu_read_unlock();
56 	return ret;
57 }
58 
59 /* Search for mac entry. Caller must hold rcu read lock.
60  */
find_node_by_addr_A(struct list_head * node_db,const unsigned char addr[ETH_ALEN])61 static struct hsr_node *find_node_by_addr_A(struct list_head *node_db,
62 					    const unsigned char addr[ETH_ALEN])
63 {
64 	struct hsr_node *node;
65 
66 	list_for_each_entry_rcu(node, node_db, mac_list) {
67 		if (ether_addr_equal(node->macaddress_A, addr))
68 			return node;
69 	}
70 
71 	return NULL;
72 }
73 
74 /* Helper for device init; the self_node is used in hsr_rcv() to recognize
75  * frames from self that's been looped over the HSR ring.
76  */
hsr_create_self_node(struct hsr_priv * hsr,const unsigned char addr_a[ETH_ALEN],const unsigned char addr_b[ETH_ALEN])77 int hsr_create_self_node(struct hsr_priv *hsr,
78 			 const unsigned char addr_a[ETH_ALEN],
79 			 const unsigned char addr_b[ETH_ALEN])
80 {
81 	struct hsr_self_node *sn, *old;
82 
83 	sn = kmalloc(sizeof(*sn), GFP_KERNEL);
84 	if (!sn)
85 		return -ENOMEM;
86 
87 	ether_addr_copy(sn->macaddress_A, addr_a);
88 	ether_addr_copy(sn->macaddress_B, addr_b);
89 
90 	spin_lock_bh(&hsr->list_lock);
91 	old = rcu_replace_pointer(hsr->self_node, sn,
92 				  lockdep_is_held(&hsr->list_lock));
93 	spin_unlock_bh(&hsr->list_lock);
94 
95 	if (old)
96 		kfree_rcu(old, rcu_head);
97 	return 0;
98 }
99 
hsr_del_self_node(struct hsr_priv * hsr)100 void hsr_del_self_node(struct hsr_priv *hsr)
101 {
102 	struct hsr_self_node *old;
103 
104 	spin_lock_bh(&hsr->list_lock);
105 	old = rcu_replace_pointer(hsr->self_node, NULL,
106 				  lockdep_is_held(&hsr->list_lock));
107 	spin_unlock_bh(&hsr->list_lock);
108 	if (old)
109 		kfree_rcu(old, rcu_head);
110 }
111 
hsr_del_nodes(struct list_head * node_db)112 void hsr_del_nodes(struct list_head *node_db)
113 {
114 	struct hsr_node *node;
115 	struct hsr_node *tmp;
116 
117 	list_for_each_entry_safe(node, tmp, node_db, mac_list)
118 		kfree(node);
119 }
120 
prp_handle_san_frame(bool san,enum hsr_port_type port,struct hsr_node * node)121 void prp_handle_san_frame(bool san, enum hsr_port_type port,
122 			  struct hsr_node *node)
123 {
124 	/* Mark if the SAN node is over LAN_A or LAN_B */
125 	if (port == HSR_PT_SLAVE_A) {
126 		node->san_a = true;
127 		return;
128 	}
129 
130 	if (port == HSR_PT_SLAVE_B)
131 		node->san_b = true;
132 }
133 
134 /* Allocate an hsr_node and add it to node_db. 'addr' is the node's address_A;
135  * seq_out is used to initialize filtering of outgoing duplicate frames
136  * originating from the newly added node.
137  */
hsr_add_node(struct hsr_priv * hsr,struct list_head * node_db,unsigned char addr[],u16 seq_out,bool san,enum hsr_port_type rx_port)138 static struct hsr_node *hsr_add_node(struct hsr_priv *hsr,
139 				     struct list_head *node_db,
140 				     unsigned char addr[],
141 				     u16 seq_out, bool san,
142 				     enum hsr_port_type rx_port)
143 {
144 	struct hsr_node *new_node, *node;
145 	unsigned long now;
146 	int i;
147 
148 	new_node = kzalloc(sizeof(*new_node), GFP_ATOMIC);
149 	if (!new_node)
150 		return NULL;
151 
152 	ether_addr_copy(new_node->macaddress_A, addr);
153 	spin_lock_init(&new_node->seq_out_lock);
154 
155 	/* We are only interested in time diffs here, so use current jiffies
156 	 * as initialization. (0 could trigger an spurious ring error warning).
157 	 */
158 	now = jiffies;
159 	for (i = 0; i < HSR_PT_PORTS; i++) {
160 		new_node->time_in[i] = now;
161 		new_node->time_out[i] = now;
162 	}
163 	for (i = 0; i < HSR_PT_PORTS; i++)
164 		new_node->seq_out[i] = seq_out;
165 
166 	if (san && hsr->proto_ops->handle_san_frame)
167 		hsr->proto_ops->handle_san_frame(san, rx_port, new_node);
168 
169 	spin_lock_bh(&hsr->list_lock);
170 	list_for_each_entry_rcu(node, node_db, mac_list,
171 				lockdep_is_held(&hsr->list_lock)) {
172 		if (ether_addr_equal(node->macaddress_A, addr))
173 			goto out;
174 		if (ether_addr_equal(node->macaddress_B, addr))
175 			goto out;
176 	}
177 	list_add_tail_rcu(&new_node->mac_list, node_db);
178 	spin_unlock_bh(&hsr->list_lock);
179 	return new_node;
180 out:
181 	spin_unlock_bh(&hsr->list_lock);
182 	kfree(new_node);
183 	return node;
184 }
185 
prp_update_san_info(struct hsr_node * node,bool is_sup)186 void prp_update_san_info(struct hsr_node *node, bool is_sup)
187 {
188 	if (!is_sup)
189 		return;
190 
191 	node->san_a = false;
192 	node->san_b = false;
193 }
194 
195 /* Get the hsr_node from which 'skb' was sent.
196  */
hsr_get_node(struct hsr_port * port,struct list_head * node_db,struct sk_buff * skb,bool is_sup,enum hsr_port_type rx_port)197 struct hsr_node *hsr_get_node(struct hsr_port *port, struct list_head *node_db,
198 			      struct sk_buff *skb, bool is_sup,
199 			      enum hsr_port_type rx_port)
200 {
201 	struct hsr_priv *hsr = port->hsr;
202 	struct hsr_node *node;
203 	struct ethhdr *ethhdr;
204 	struct prp_rct *rct;
205 	bool san = false;
206 	u16 seq_out;
207 
208 	if (!skb_mac_header_was_set(skb))
209 		return NULL;
210 
211 	ethhdr = (struct ethhdr *)skb_mac_header(skb);
212 
213 	list_for_each_entry_rcu(node, node_db, mac_list) {
214 		if (ether_addr_equal(node->macaddress_A, ethhdr->h_source)) {
215 			if (hsr->proto_ops->update_san_info)
216 				hsr->proto_ops->update_san_info(node, is_sup);
217 			return node;
218 		}
219 		if (ether_addr_equal(node->macaddress_B, ethhdr->h_source)) {
220 			if (hsr->proto_ops->update_san_info)
221 				hsr->proto_ops->update_san_info(node, is_sup);
222 			return node;
223 		}
224 	}
225 
226 	/* Everyone may create a node entry, connected node to a HSR/PRP
227 	 * device.
228 	 */
229 	if (ethhdr->h_proto == htons(ETH_P_PRP) ||
230 	    ethhdr->h_proto == htons(ETH_P_HSR)) {
231 		/* Check if skb contains hsr_ethhdr */
232 		if (skb->mac_len < sizeof(struct hsr_ethhdr))
233 			return NULL;
234 
235 		/* Use the existing sequence_nr from the tag as starting point
236 		 * for filtering duplicate frames.
237 		 */
238 		seq_out = hsr_get_skb_sequence_nr(skb) - 1;
239 	} else {
240 		rct = skb_get_PRP_rct(skb);
241 		if (rct && prp_check_lsdu_size(skb, rct, is_sup)) {
242 			seq_out = prp_get_skb_sequence_nr(rct);
243 		} else {
244 			if (rx_port != HSR_PT_MASTER)
245 				san = true;
246 			seq_out = HSR_SEQNR_START;
247 		}
248 	}
249 
250 	return hsr_add_node(hsr, node_db, ethhdr->h_source, seq_out,
251 			    san, rx_port);
252 }
253 
254 /* Use the Supervision frame's info about an eventual macaddress_B for merging
255  * nodes that has previously had their macaddress_B registered as a separate
256  * node.
257  */
hsr_handle_sup_frame(struct hsr_frame_info * frame)258 void hsr_handle_sup_frame(struct hsr_frame_info *frame)
259 {
260 	struct hsr_node *node_curr = frame->node_src;
261 	struct hsr_port *port_rcv = frame->port_rcv;
262 	struct hsr_priv *hsr = port_rcv->hsr;
263 	struct hsr_sup_payload *hsr_sp;
264 	struct hsr_sup_tlv *hsr_sup_tlv;
265 	struct hsr_node *node_real;
266 	struct sk_buff *skb = NULL;
267 	struct list_head *node_db;
268 	struct ethhdr *ethhdr;
269 	int i;
270 	unsigned int pull_size = 0;
271 	unsigned int total_pull_size = 0;
272 
273 	/* Here either frame->skb_hsr or frame->skb_prp should be
274 	 * valid as supervision frame always will have protocol
275 	 * header info.
276 	 */
277 	if (frame->skb_hsr)
278 		skb = frame->skb_hsr;
279 	else if (frame->skb_prp)
280 		skb = frame->skb_prp;
281 	else if (frame->skb_std)
282 		skb = frame->skb_std;
283 	if (!skb)
284 		return;
285 
286 	/* Leave the ethernet header. */
287 	pull_size = sizeof(struct ethhdr);
288 	skb_pull(skb, pull_size);
289 	total_pull_size += pull_size;
290 
291 	ethhdr = (struct ethhdr *)skb_mac_header(skb);
292 
293 	/* And leave the HSR tag. */
294 	if (ethhdr->h_proto == htons(ETH_P_HSR)) {
295 		pull_size = sizeof(struct hsr_tag);
296 		skb_pull(skb, pull_size);
297 		total_pull_size += pull_size;
298 	}
299 
300 	/* And leave the HSR sup tag. */
301 	pull_size = sizeof(struct hsr_sup_tag);
302 	skb_pull(skb, pull_size);
303 	total_pull_size += pull_size;
304 
305 	/* get HSR sup payload */
306 	hsr_sp = (struct hsr_sup_payload *)skb->data;
307 
308 	/* Merge node_curr (registered on macaddress_B) into node_real */
309 	node_db = &port_rcv->hsr->node_db;
310 	node_real = find_node_by_addr_A(node_db, hsr_sp->macaddress_A);
311 	if (!node_real)
312 		/* No frame received from AddrA of this node yet */
313 		node_real = hsr_add_node(hsr, node_db, hsr_sp->macaddress_A,
314 					 HSR_SEQNR_START - 1, true,
315 					 port_rcv->type);
316 	if (!node_real)
317 		goto done; /* No mem */
318 	if (node_real == node_curr)
319 		/* Node has already been merged */
320 		goto done;
321 
322 	/* Leave the first HSR sup payload. */
323 	pull_size = sizeof(struct hsr_sup_payload);
324 	skb_pull(skb, pull_size);
325 	total_pull_size += pull_size;
326 
327 	/* Get second supervision tlv */
328 	hsr_sup_tlv = (struct hsr_sup_tlv *)skb->data;
329 	/* And check if it is a redbox mac TLV */
330 	if (hsr_sup_tlv->HSR_TLV_type == PRP_TLV_REDBOX_MAC) {
331 		/* We could stop here after pushing hsr_sup_payload,
332 		 * or proceed and allow macaddress_B and for redboxes.
333 		 */
334 		/* Sanity check length */
335 		if (hsr_sup_tlv->HSR_TLV_length != 6)
336 			goto done;
337 
338 		/* Leave the second HSR sup tlv. */
339 		pull_size = sizeof(struct hsr_sup_tlv);
340 		skb_pull(skb, pull_size);
341 		total_pull_size += pull_size;
342 
343 		/* Get redbox mac address. */
344 		hsr_sp = (struct hsr_sup_payload *)skb->data;
345 
346 		/* Check if redbox mac and node mac are equal. */
347 		if (!ether_addr_equal(node_real->macaddress_A, hsr_sp->macaddress_A)) {
348 			/* This is a redbox supervision frame for a VDAN! */
349 			goto done;
350 		}
351 	}
352 
353 	ether_addr_copy(node_real->macaddress_B, ethhdr->h_source);
354 	spin_lock_bh(&node_real->seq_out_lock);
355 	for (i = 0; i < HSR_PT_PORTS; i++) {
356 		if (!node_curr->time_in_stale[i] &&
357 		    time_after(node_curr->time_in[i], node_real->time_in[i])) {
358 			node_real->time_in[i] = node_curr->time_in[i];
359 			node_real->time_in_stale[i] =
360 						node_curr->time_in_stale[i];
361 		}
362 		if (seq_nr_after(node_curr->seq_out[i], node_real->seq_out[i]))
363 			node_real->seq_out[i] = node_curr->seq_out[i];
364 	}
365 	spin_unlock_bh(&node_real->seq_out_lock);
366 	node_real->addr_B_port = port_rcv->type;
367 
368 	spin_lock_bh(&hsr->list_lock);
369 	if (!node_curr->removed) {
370 		list_del_rcu(&node_curr->mac_list);
371 		node_curr->removed = true;
372 		kfree_rcu(node_curr, rcu_head);
373 	}
374 	spin_unlock_bh(&hsr->list_lock);
375 
376 done:
377 	/* Push back here */
378 	skb_push(skb, total_pull_size);
379 }
380 
381 /* 'skb' is a frame meant for this host, that is to be passed to upper layers.
382  *
383  * If the frame was sent by a node's B interface, replace the source
384  * address with that node's "official" address (macaddress_A) so that upper
385  * layers recognize where it came from.
386  */
hsr_addr_subst_source(struct hsr_node * node,struct sk_buff * skb)387 void hsr_addr_subst_source(struct hsr_node *node, struct sk_buff *skb)
388 {
389 	if (!skb_mac_header_was_set(skb)) {
390 		WARN_ONCE(1, "%s: Mac header not set\n", __func__);
391 		return;
392 	}
393 
394 	memcpy(&eth_hdr(skb)->h_source, node->macaddress_A, ETH_ALEN);
395 }
396 
397 /* 'skb' is a frame meant for another host.
398  * 'port' is the outgoing interface
399  *
400  * Substitute the target (dest) MAC address if necessary, so the it matches the
401  * recipient interface MAC address, regardless of whether that is the
402  * recipient's A or B interface.
403  * This is needed to keep the packets flowing through switches that learn on
404  * which "side" the different interfaces are.
405  */
hsr_addr_subst_dest(struct hsr_node * node_src,struct sk_buff * skb,struct hsr_port * port)406 void hsr_addr_subst_dest(struct hsr_node *node_src, struct sk_buff *skb,
407 			 struct hsr_port *port)
408 {
409 	struct hsr_node *node_dst;
410 
411 	if (!skb_mac_header_was_set(skb)) {
412 		WARN_ONCE(1, "%s: Mac header not set\n", __func__);
413 		return;
414 	}
415 
416 	if (!is_unicast_ether_addr(eth_hdr(skb)->h_dest))
417 		return;
418 
419 	node_dst = find_node_by_addr_A(&port->hsr->node_db,
420 				       eth_hdr(skb)->h_dest);
421 	if (!node_dst) {
422 		if (port->hsr->prot_version != PRP_V1 && net_ratelimit())
423 			netdev_err(skb->dev, "%s: Unknown node\n", __func__);
424 		return;
425 	}
426 	if (port->type != node_dst->addr_B_port)
427 		return;
428 
429 	if (is_valid_ether_addr(node_dst->macaddress_B))
430 		ether_addr_copy(eth_hdr(skb)->h_dest, node_dst->macaddress_B);
431 }
432 
hsr_register_frame_in(struct hsr_node * node,struct hsr_port * port,u16 sequence_nr)433 void hsr_register_frame_in(struct hsr_node *node, struct hsr_port *port,
434 			   u16 sequence_nr)
435 {
436 	/* Don't register incoming frames without a valid sequence number. This
437 	 * ensures entries of restarted nodes gets pruned so that they can
438 	 * re-register and resume communications.
439 	 */
440 	if (!(port->dev->features & NETIF_F_HW_HSR_TAG_RM) &&
441 	    seq_nr_before(sequence_nr, node->seq_out[port->type]))
442 		return;
443 
444 	node->time_in[port->type] = jiffies;
445 	node->time_in_stale[port->type] = false;
446 }
447 
448 /* 'skb' is a HSR Ethernet frame (with a HSR tag inserted), with a valid
449  * ethhdr->h_source address and skb->mac_header set.
450  *
451  * Return:
452  *	 1 if frame can be shown to have been sent recently on this interface,
453  *	 0 otherwise, or
454  *	 negative error code on error
455  */
hsr_register_frame_out(struct hsr_port * port,struct hsr_node * node,u16 sequence_nr)456 int hsr_register_frame_out(struct hsr_port *port, struct hsr_node *node,
457 			   u16 sequence_nr)
458 {
459 	spin_lock_bh(&node->seq_out_lock);
460 	if (seq_nr_before_or_eq(sequence_nr, node->seq_out[port->type]) &&
461 	    time_is_after_jiffies(node->time_out[port->type] +
462 	    msecs_to_jiffies(HSR_ENTRY_FORGET_TIME))) {
463 		spin_unlock_bh(&node->seq_out_lock);
464 		return 1;
465 	}
466 
467 	node->time_out[port->type] = jiffies;
468 	node->seq_out[port->type] = sequence_nr;
469 	spin_unlock_bh(&node->seq_out_lock);
470 	return 0;
471 }
472 
get_late_port(struct hsr_priv * hsr,struct hsr_node * node)473 static struct hsr_port *get_late_port(struct hsr_priv *hsr,
474 				      struct hsr_node *node)
475 {
476 	if (node->time_in_stale[HSR_PT_SLAVE_A])
477 		return hsr_port_get_hsr(hsr, HSR_PT_SLAVE_A);
478 	if (node->time_in_stale[HSR_PT_SLAVE_B])
479 		return hsr_port_get_hsr(hsr, HSR_PT_SLAVE_B);
480 
481 	if (time_after(node->time_in[HSR_PT_SLAVE_B],
482 		       node->time_in[HSR_PT_SLAVE_A] +
483 					msecs_to_jiffies(MAX_SLAVE_DIFF)))
484 		return hsr_port_get_hsr(hsr, HSR_PT_SLAVE_A);
485 	if (time_after(node->time_in[HSR_PT_SLAVE_A],
486 		       node->time_in[HSR_PT_SLAVE_B] +
487 					msecs_to_jiffies(MAX_SLAVE_DIFF)))
488 		return hsr_port_get_hsr(hsr, HSR_PT_SLAVE_B);
489 
490 	return NULL;
491 }
492 
493 /* Remove stale sequence_nr records. Called by timer every
494  * HSR_LIFE_CHECK_INTERVAL (two seconds or so).
495  */
hsr_prune_nodes(struct timer_list * t)496 void hsr_prune_nodes(struct timer_list *t)
497 {
498 	struct hsr_priv *hsr = from_timer(hsr, t, prune_timer);
499 	struct hsr_node *node;
500 	struct hsr_node *tmp;
501 	struct hsr_port *port;
502 	unsigned long timestamp;
503 	unsigned long time_a, time_b;
504 
505 	spin_lock_bh(&hsr->list_lock);
506 	list_for_each_entry_safe(node, tmp, &hsr->node_db, mac_list) {
507 		/* Don't prune own node. Neither time_in[HSR_PT_SLAVE_A]
508 		 * nor time_in[HSR_PT_SLAVE_B], will ever be updated for
509 		 * the master port. Thus the master node will be repeatedly
510 		 * pruned leading to packet loss.
511 		 */
512 		if (hsr_addr_is_self(hsr, node->macaddress_A))
513 			continue;
514 
515 		/* Shorthand */
516 		time_a = node->time_in[HSR_PT_SLAVE_A];
517 		time_b = node->time_in[HSR_PT_SLAVE_B];
518 
519 		/* Check for timestamps old enough to risk wrap-around */
520 		if (time_after(jiffies, time_a + MAX_JIFFY_OFFSET / 2))
521 			node->time_in_stale[HSR_PT_SLAVE_A] = true;
522 		if (time_after(jiffies, time_b + MAX_JIFFY_OFFSET / 2))
523 			node->time_in_stale[HSR_PT_SLAVE_B] = true;
524 
525 		/* Get age of newest frame from node.
526 		 * At least one time_in is OK here; nodes get pruned long
527 		 * before both time_ins can get stale
528 		 */
529 		timestamp = time_a;
530 		if (node->time_in_stale[HSR_PT_SLAVE_A] ||
531 		    (!node->time_in_stale[HSR_PT_SLAVE_B] &&
532 		    time_after(time_b, time_a)))
533 			timestamp = time_b;
534 
535 		/* Warn of ring error only as long as we get frames at all */
536 		if (time_is_after_jiffies(timestamp +
537 				msecs_to_jiffies(1.5 * MAX_SLAVE_DIFF))) {
538 			rcu_read_lock();
539 			port = get_late_port(hsr, node);
540 			if (port)
541 				hsr_nl_ringerror(hsr, node->macaddress_A, port);
542 			rcu_read_unlock();
543 		}
544 
545 		/* Prune old entries */
546 		if (time_is_before_jiffies(timestamp +
547 				msecs_to_jiffies(HSR_NODE_FORGET_TIME))) {
548 			hsr_nl_nodedown(hsr, node->macaddress_A);
549 			if (!node->removed) {
550 				list_del_rcu(&node->mac_list);
551 				node->removed = true;
552 				/* Note that we need to free this entry later: */
553 				kfree_rcu(node, rcu_head);
554 			}
555 		}
556 	}
557 	spin_unlock_bh(&hsr->list_lock);
558 
559 	/* Restart timer */
560 	mod_timer(&hsr->prune_timer,
561 		  jiffies + msecs_to_jiffies(PRUNE_PERIOD));
562 }
563 
hsr_get_next_node(struct hsr_priv * hsr,void * _pos,unsigned char addr[ETH_ALEN])564 void *hsr_get_next_node(struct hsr_priv *hsr, void *_pos,
565 			unsigned char addr[ETH_ALEN])
566 {
567 	struct hsr_node *node;
568 
569 	if (!_pos) {
570 		node = list_first_or_null_rcu(&hsr->node_db,
571 					      struct hsr_node, mac_list);
572 		if (node)
573 			ether_addr_copy(addr, node->macaddress_A);
574 		return node;
575 	}
576 
577 	node = _pos;
578 	list_for_each_entry_continue_rcu(node, &hsr->node_db, mac_list) {
579 		ether_addr_copy(addr, node->macaddress_A);
580 		return node;
581 	}
582 
583 	return NULL;
584 }
585 
hsr_get_node_data(struct hsr_priv * hsr,const unsigned char * addr,unsigned char addr_b[ETH_ALEN],unsigned int * addr_b_ifindex,int * if1_age,u16 * if1_seq,int * if2_age,u16 * if2_seq)586 int hsr_get_node_data(struct hsr_priv *hsr,
587 		      const unsigned char *addr,
588 		      unsigned char addr_b[ETH_ALEN],
589 		      unsigned int *addr_b_ifindex,
590 		      int *if1_age,
591 		      u16 *if1_seq,
592 		      int *if2_age,
593 		      u16 *if2_seq)
594 {
595 	struct hsr_node *node;
596 	struct hsr_port *port;
597 	unsigned long tdiff;
598 
599 	node = find_node_by_addr_A(&hsr->node_db, addr);
600 	if (!node)
601 		return -ENOENT;
602 
603 	ether_addr_copy(addr_b, node->macaddress_B);
604 
605 	tdiff = jiffies - node->time_in[HSR_PT_SLAVE_A];
606 	if (node->time_in_stale[HSR_PT_SLAVE_A])
607 		*if1_age = INT_MAX;
608 #if HZ <= MSEC_PER_SEC
609 	else if (tdiff > msecs_to_jiffies(INT_MAX))
610 		*if1_age = INT_MAX;
611 #endif
612 	else
613 		*if1_age = jiffies_to_msecs(tdiff);
614 
615 	tdiff = jiffies - node->time_in[HSR_PT_SLAVE_B];
616 	if (node->time_in_stale[HSR_PT_SLAVE_B])
617 		*if2_age = INT_MAX;
618 #if HZ <= MSEC_PER_SEC
619 	else if (tdiff > msecs_to_jiffies(INT_MAX))
620 		*if2_age = INT_MAX;
621 #endif
622 	else
623 		*if2_age = jiffies_to_msecs(tdiff);
624 
625 	/* Present sequence numbers as if they were incoming on interface */
626 	*if1_seq = node->seq_out[HSR_PT_SLAVE_B];
627 	*if2_seq = node->seq_out[HSR_PT_SLAVE_A];
628 
629 	if (node->addr_B_port != HSR_PT_NONE) {
630 		port = hsr_port_get_hsr(hsr, node->addr_B_port);
631 		*addr_b_ifindex = port->dev->ifindex;
632 	} else {
633 		*addr_b_ifindex = -1;
634 	}
635 
636 	return 0;
637 }
638