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Arvid Brodinf4214362013-10-30 21:10:47 +01001/* Copyright 2011-2013 Autronica Fire and Security AS
2 *
3 * This program is free software; you can redistribute it and/or modify it
4 * under the terms of the GNU General Public License as published by the Free
5 * Software Foundation; either version 2 of the License, or (at your option)
6 * any later version.
7 *
8 * Author(s):
9 * 2011-2013 Arvid Brodin, arvid.brodin@xdin.com
10 *
11 * The HSR spec says never to forward the same frame twice on the same
12 * interface. A frame is identified by its source MAC address and its HSR
13 * sequence number. This code keeps track of senders and their sequence numbers
14 * to allow filtering of duplicate frames, and to detect HSR ring errors.
15 */
16
17#include <linux/if_ether.h>
18#include <linux/etherdevice.h>
19#include <linux/slab.h>
20#include <linux/rculist.h>
21#include "hsr_main.h"
22#include "hsr_framereg.h"
23#include "hsr_netlink.h"
24
25
26struct node_entry {
27 struct list_head mac_list;
28 unsigned char MacAddressA[ETH_ALEN];
29 unsigned char MacAddressB[ETH_ALEN];
30 enum hsr_dev_idx AddrB_if; /* The local slave through which AddrB
31 * frames are received from this node
32 */
33 unsigned long time_in[HSR_MAX_SLAVE];
34 bool time_in_stale[HSR_MAX_SLAVE];
35 u16 seq_out[HSR_MAX_DEV];
36 struct rcu_head rcu_head;
37};
38
39/* TODO: use hash lists for mac addresses (linux/jhash.h)? */
40
41
42
43/* Search for mac entry. Caller must hold rcu read lock.
44 */
45static struct node_entry *find_node_by_AddrA(struct list_head *node_db,
46 const unsigned char addr[ETH_ALEN])
47{
48 struct node_entry *node;
49
50 list_for_each_entry_rcu(node, node_db, mac_list) {
51 if (ether_addr_equal(node->MacAddressA, addr))
52 return node;
53 }
54
55 return NULL;
56}
57
58
59/* Search for mac entry. Caller must hold rcu read lock.
60 */
61static struct node_entry *find_node_by_AddrB(struct list_head *node_db,
62 const unsigned char addr[ETH_ALEN])
63{
64 struct node_entry *node;
65
66 list_for_each_entry_rcu(node, node_db, mac_list) {
67 if (ether_addr_equal(node->MacAddressB, addr))
68 return node;
69 }
70
71 return NULL;
72}
73
74
75/* Search for mac entry. Caller must hold rcu read lock.
76 */
77struct node_entry *hsr_find_node(struct list_head *node_db, struct sk_buff *skb)
78{
79 struct node_entry *node;
80 struct ethhdr *ethhdr;
81
82 if (!skb_mac_header_was_set(skb))
83 return NULL;
84
85 ethhdr = (struct ethhdr *) skb_mac_header(skb);
86
87 list_for_each_entry_rcu(node, node_db, mac_list) {
88 if (ether_addr_equal(node->MacAddressA, ethhdr->h_source))
89 return node;
90 if (ether_addr_equal(node->MacAddressB, ethhdr->h_source))
91 return node;
92 }
93
94 return NULL;
95}
96
97
98/* Helper for device init; the self_node_db is used in hsr_rcv() to recognize
99 * frames from self that's been looped over the HSR ring.
100 */
101int hsr_create_self_node(struct list_head *self_node_db,
102 unsigned char addr_a[ETH_ALEN],
103 unsigned char addr_b[ETH_ALEN])
104{
105 struct node_entry *node, *oldnode;
106
107 node = kmalloc(sizeof(*node), GFP_KERNEL);
108 if (!node)
109 return -ENOMEM;
110
111 memcpy(node->MacAddressA, addr_a, ETH_ALEN);
112 memcpy(node->MacAddressB, addr_b, ETH_ALEN);
113
114 rcu_read_lock();
115 oldnode = list_first_or_null_rcu(self_node_db,
116 struct node_entry, mac_list);
117 if (oldnode) {
118 list_replace_rcu(&oldnode->mac_list, &node->mac_list);
119 rcu_read_unlock();
120 synchronize_rcu();
121 kfree(oldnode);
122 } else {
123 rcu_read_unlock();
124 list_add_tail_rcu(&node->mac_list, self_node_db);
125 }
126
127 return 0;
128}
129
Arvid Brodinf4214362013-10-30 21:10:47 +0100130
131/* Add/merge node to the database of nodes. 'skb' must contain an HSR
132 * supervision frame.
133 * - If the supervision header's MacAddressA field is not yet in the database,
134 * this frame is from an hitherto unknown node - add it to the database.
135 * - If the sender's MAC address is not the same as its MacAddressA address,
136 * the node is using PICS_SUBS (address substitution). Record the sender's
137 * address as the node's MacAddressB.
138 *
139 * This function needs to work even if the sender node has changed one of its
140 * slaves' MAC addresses. In this case, there are four different cases described
141 * by (Addr-changed, received-from) pairs as follows. Note that changing the
142 * SlaveA address is equal to changing the node's own address:
143 *
144 * - (AddrB, SlaveB): The new AddrB will be recorded by PICS_SUBS code since
145 * node == NULL.
146 * - (AddrB, SlaveA): Will work as usual (the AddrB change won't be detected
147 * from this frame).
148 *
149 * - (AddrA, SlaveB): The old node will be found. We need to detect this and
150 * remove the node.
151 * - (AddrA, SlaveA): A new node will be registered (non-PICS_SUBS at first).
152 * The old one will be pruned after HSR_NODE_FORGET_TIME.
153 *
154 * We also need to detect if the sender's SlaveA and SlaveB cables have been
155 * swapped.
156 */
157struct node_entry *hsr_merge_node(struct hsr_priv *hsr_priv,
158 struct node_entry *node,
159 struct sk_buff *skb,
160 enum hsr_dev_idx dev_idx)
161{
162 struct hsr_sup_payload *hsr_sp;
163 struct hsr_ethhdr_sp *hsr_ethsup;
164 int i;
165 unsigned long now;
166
167 hsr_ethsup = (struct hsr_ethhdr_sp *) skb_mac_header(skb);
168 hsr_sp = (struct hsr_sup_payload *) skb->data;
169
170 if (node && !ether_addr_equal(node->MacAddressA, hsr_sp->MacAddressA)) {
171 /* Node has changed its AddrA, frame was received from SlaveB */
172 list_del_rcu(&node->mac_list);
Wei Yongjun1aee6cc2013-12-16 14:05:50 +0800173 kfree_rcu(node, rcu_head);
Arvid Brodinf4214362013-10-30 21:10:47 +0100174 node = NULL;
175 }
176
177 if (node && (dev_idx == node->AddrB_if) &&
178 !ether_addr_equal(node->MacAddressB, hsr_ethsup->ethhdr.h_source)) {
179 /* Cables have been swapped */
180 list_del_rcu(&node->mac_list);
Wei Yongjun1aee6cc2013-12-16 14:05:50 +0800181 kfree_rcu(node, rcu_head);
Arvid Brodinf4214362013-10-30 21:10:47 +0100182 node = NULL;
183 }
184
185 if (node && (dev_idx != node->AddrB_if) &&
186 (node->AddrB_if != HSR_DEV_NONE) &&
187 !ether_addr_equal(node->MacAddressA, hsr_ethsup->ethhdr.h_source)) {
188 /* Cables have been swapped */
189 list_del_rcu(&node->mac_list);
Wei Yongjun1aee6cc2013-12-16 14:05:50 +0800190 kfree_rcu(node, rcu_head);
Arvid Brodinf4214362013-10-30 21:10:47 +0100191 node = NULL;
192 }
193
194 if (node)
195 return node;
196
197 node = find_node_by_AddrA(&hsr_priv->node_db, hsr_sp->MacAddressA);
198 if (node) {
199 /* Node is known, but frame was received from an unknown
200 * address. Node is PICS_SUBS capable; merge its AddrB.
201 */
202 memcpy(node->MacAddressB, hsr_ethsup->ethhdr.h_source, ETH_ALEN);
203 node->AddrB_if = dev_idx;
204 return node;
205 }
206
207 node = kzalloc(sizeof(*node), GFP_ATOMIC);
208 if (!node)
209 return NULL;
210
211 memcpy(node->MacAddressA, hsr_sp->MacAddressA, ETH_ALEN);
212 memcpy(node->MacAddressB, hsr_ethsup->ethhdr.h_source, ETH_ALEN);
213 if (!ether_addr_equal(hsr_sp->MacAddressA, hsr_ethsup->ethhdr.h_source))
214 node->AddrB_if = dev_idx;
215 else
216 node->AddrB_if = HSR_DEV_NONE;
217
218 /* We are only interested in time diffs here, so use current jiffies
219 * as initialization. (0 could trigger an spurious ring error warning).
220 */
221 now = jiffies;
222 for (i = 0; i < HSR_MAX_SLAVE; i++)
223 node->time_in[i] = now;
224 for (i = 0; i < HSR_MAX_DEV; i++)
225 node->seq_out[i] = ntohs(hsr_ethsup->hsr_sup.sequence_nr) - 1;
226
227 list_add_tail_rcu(&node->mac_list, &hsr_priv->node_db);
228
229 return node;
230}
231
232
233/* 'skb' is a frame meant for this host, that is to be passed to upper layers.
234 *
235 * If the frame was sent by a node's B interface, replace the sender
236 * address with that node's "official" address (MacAddressA) so that upper
237 * layers recognize where it came from.
238 */
239void hsr_addr_subst_source(struct hsr_priv *hsr_priv, struct sk_buff *skb)
240{
241 struct ethhdr *ethhdr;
242 struct node_entry *node;
243
244 if (!skb_mac_header_was_set(skb)) {
245 WARN_ONCE(1, "%s: Mac header not set\n", __func__);
246 return;
247 }
248 ethhdr = (struct ethhdr *) skb_mac_header(skb);
249
250 rcu_read_lock();
251 node = find_node_by_AddrB(&hsr_priv->node_db, ethhdr->h_source);
252 if (node)
253 memcpy(ethhdr->h_source, node->MacAddressA, ETH_ALEN);
254 rcu_read_unlock();
255}
256
257
258/* 'skb' is a frame meant for another host.
259 * 'hsr_dev_idx' is the HSR index of the outgoing device
260 *
261 * Substitute the target (dest) MAC address if necessary, so the it matches the
262 * recipient interface MAC address, regardless of whether that is the
263 * recipient's A or B interface.
264 * This is needed to keep the packets flowing through switches that learn on
265 * which "side" the different interfaces are.
266 */
267void hsr_addr_subst_dest(struct hsr_priv *hsr_priv, struct ethhdr *ethhdr,
268 enum hsr_dev_idx dev_idx)
269{
270 struct node_entry *node;
271
272 rcu_read_lock();
273 node = find_node_by_AddrA(&hsr_priv->node_db, ethhdr->h_dest);
274 if (node && (node->AddrB_if == dev_idx))
275 memcpy(ethhdr->h_dest, node->MacAddressB, ETH_ALEN);
276 rcu_read_unlock();
277}
278
279
280/* seq_nr_after(a, b) - return true if a is after (higher in sequence than) b,
281 * false otherwise.
282 */
283static bool seq_nr_after(u16 a, u16 b)
284{
285 /* Remove inconsistency where
Arvid Brodin213e3bc2013-11-29 23:37:07 +0100286 * seq_nr_after(a, b) == seq_nr_before(a, b)
287 */
Arvid Brodinf4214362013-10-30 21:10:47 +0100288 if ((int) b - a == 32768)
289 return false;
290
291 return (((s16) (b - a)) < 0);
292}
293#define seq_nr_before(a, b) seq_nr_after((b), (a))
294#define seq_nr_after_or_eq(a, b) (!seq_nr_before((a), (b)))
295#define seq_nr_before_or_eq(a, b) (!seq_nr_after((a), (b)))
296
297
298void hsr_register_frame_in(struct node_entry *node, enum hsr_dev_idx dev_idx)
299{
300 if ((dev_idx < 0) || (dev_idx >= HSR_MAX_DEV)) {
301 WARN_ONCE(1, "%s: Invalid dev_idx (%d)\n", __func__, dev_idx);
302 return;
303 }
304 node->time_in[dev_idx] = jiffies;
305 node->time_in_stale[dev_idx] = false;
306}
307
308
309/* 'skb' is a HSR Ethernet frame (with a HSR tag inserted), with a valid
310 * ethhdr->h_source address and skb->mac_header set.
311 *
312 * Return:
313 * 1 if frame can be shown to have been sent recently on this interface,
314 * 0 otherwise, or
315 * negative error code on error
316 */
317int hsr_register_frame_out(struct node_entry *node, enum hsr_dev_idx dev_idx,
318 struct sk_buff *skb)
319{
320 struct hsr_ethhdr *hsr_ethhdr;
321 u16 sequence_nr;
322
323 if ((dev_idx < 0) || (dev_idx >= HSR_MAX_DEV)) {
324 WARN_ONCE(1, "%s: Invalid dev_idx (%d)\n", __func__, dev_idx);
325 return -EINVAL;
326 }
327 if (!skb_mac_header_was_set(skb)) {
328 WARN_ONCE(1, "%s: Mac header not set\n", __func__);
329 return -EINVAL;
330 }
331 hsr_ethhdr = (struct hsr_ethhdr *) skb_mac_header(skb);
332
333 sequence_nr = ntohs(hsr_ethhdr->hsr_tag.sequence_nr);
334 if (seq_nr_before_or_eq(sequence_nr, node->seq_out[dev_idx]))
335 return 1;
336
337 node->seq_out[dev_idx] = sequence_nr;
338 return 0;
339}
340
341
342
343static bool is_late(struct node_entry *node, enum hsr_dev_idx dev_idx)
344{
345 enum hsr_dev_idx other;
346
347 if (node->time_in_stale[dev_idx])
348 return true;
349
350 if (dev_idx == HSR_DEV_SLAVE_A)
351 other = HSR_DEV_SLAVE_B;
352 else
353 other = HSR_DEV_SLAVE_A;
354
355 if (node->time_in_stale[other])
356 return false;
357
358 if (time_after(node->time_in[other], node->time_in[dev_idx] +
359 msecs_to_jiffies(MAX_SLAVE_DIFF)))
360 return true;
361
362 return false;
363}
364
365
366/* Remove stale sequence_nr records. Called by timer every
367 * HSR_LIFE_CHECK_INTERVAL (two seconds or so).
368 */
369void hsr_prune_nodes(struct hsr_priv *hsr_priv)
370{
371 struct node_entry *node;
372 unsigned long timestamp;
373 unsigned long time_a, time_b;
374
375 rcu_read_lock();
376 list_for_each_entry_rcu(node, &hsr_priv->node_db, mac_list) {
377 /* Shorthand */
378 time_a = node->time_in[HSR_DEV_SLAVE_A];
379 time_b = node->time_in[HSR_DEV_SLAVE_B];
380
381 /* Check for timestamps old enough to risk wrap-around */
382 if (time_after(jiffies, time_a + MAX_JIFFY_OFFSET/2))
383 node->time_in_stale[HSR_DEV_SLAVE_A] = true;
384 if (time_after(jiffies, time_b + MAX_JIFFY_OFFSET/2))
385 node->time_in_stale[HSR_DEV_SLAVE_B] = true;
386
387 /* Get age of newest frame from node.
388 * At least one time_in is OK here; nodes get pruned long
389 * before both time_ins can get stale
390 */
391 timestamp = time_a;
392 if (node->time_in_stale[HSR_DEV_SLAVE_A] ||
393 (!node->time_in_stale[HSR_DEV_SLAVE_B] &&
394 time_after(time_b, time_a)))
395 timestamp = time_b;
396
397 /* Warn of ring error only as long as we get frames at all */
398 if (time_is_after_jiffies(timestamp +
399 msecs_to_jiffies(1.5*MAX_SLAVE_DIFF))) {
400
401 if (is_late(node, HSR_DEV_SLAVE_A))
402 hsr_nl_ringerror(hsr_priv, node->MacAddressA,
403 HSR_DEV_SLAVE_A);
404 else if (is_late(node, HSR_DEV_SLAVE_B))
405 hsr_nl_ringerror(hsr_priv, node->MacAddressA,
406 HSR_DEV_SLAVE_B);
407 }
408
409 /* Prune old entries */
410 if (time_is_before_jiffies(timestamp +
411 msecs_to_jiffies(HSR_NODE_FORGET_TIME))) {
412 hsr_nl_nodedown(hsr_priv, node->MacAddressA);
413 list_del_rcu(&node->mac_list);
414 /* Note that we need to free this entry later: */
Wei Yongjun1aee6cc2013-12-16 14:05:50 +0800415 kfree_rcu(node, rcu_head);
Arvid Brodinf4214362013-10-30 21:10:47 +0100416 }
417 }
418 rcu_read_unlock();
419}
420
421
422void *hsr_get_next_node(struct hsr_priv *hsr_priv, void *_pos,
423 unsigned char addr[ETH_ALEN])
424{
425 struct node_entry *node;
426
427 if (!_pos) {
428 node = list_first_or_null_rcu(&hsr_priv->node_db,
429 struct node_entry, mac_list);
430 if (node)
431 memcpy(addr, node->MacAddressA, ETH_ALEN);
432 return node;
433 }
434
435 node = _pos;
436 list_for_each_entry_continue_rcu(node, &hsr_priv->node_db, mac_list) {
437 memcpy(addr, node->MacAddressA, ETH_ALEN);
438 return node;
439 }
440
441 return NULL;
442}
443
444
445int hsr_get_node_data(struct hsr_priv *hsr_priv,
446 const unsigned char *addr,
447 unsigned char addr_b[ETH_ALEN],
448 unsigned int *addr_b_ifindex,
449 int *if1_age,
450 u16 *if1_seq,
451 int *if2_age,
452 u16 *if2_seq)
453{
454 struct node_entry *node;
455 unsigned long tdiff;
456
457
458 rcu_read_lock();
459 node = find_node_by_AddrA(&hsr_priv->node_db, addr);
460 if (!node) {
461 rcu_read_unlock();
462 return -ENOENT; /* No such entry */
463 }
464
465 memcpy(addr_b, node->MacAddressB, ETH_ALEN);
466
467 tdiff = jiffies - node->time_in[HSR_DEV_SLAVE_A];
468 if (node->time_in_stale[HSR_DEV_SLAVE_A])
469 *if1_age = INT_MAX;
470#if HZ <= MSEC_PER_SEC
471 else if (tdiff > msecs_to_jiffies(INT_MAX))
472 *if1_age = INT_MAX;
473#endif
474 else
475 *if1_age = jiffies_to_msecs(tdiff);
476
477 tdiff = jiffies - node->time_in[HSR_DEV_SLAVE_B];
478 if (node->time_in_stale[HSR_DEV_SLAVE_B])
479 *if2_age = INT_MAX;
480#if HZ <= MSEC_PER_SEC
481 else if (tdiff > msecs_to_jiffies(INT_MAX))
482 *if2_age = INT_MAX;
483#endif
484 else
485 *if2_age = jiffies_to_msecs(tdiff);
486
487 /* Present sequence numbers as if they were incoming on interface */
488 *if1_seq = node->seq_out[HSR_DEV_SLAVE_B];
489 *if2_seq = node->seq_out[HSR_DEV_SLAVE_A];
490
491 if ((node->AddrB_if != HSR_DEV_NONE) && hsr_priv->slave[node->AddrB_if])
492 *addr_b_ifindex = hsr_priv->slave[node->AddrB_if]->ifindex;
493 else
494 *addr_b_ifindex = -1;
495
496 rcu_read_unlock();
497
498 return 0;
499}