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1 | /* 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 | ||
26 | struct 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 | */ | |
45 | static 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 | */ | |
61 | static 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 | */ | |
77 | struct 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 | */ | |
101 | int 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 | ||
130 | static void node_entry_reclaim(struct rcu_head *rh) | |
131 | { | |
132 | kfree(container_of(rh, struct node_entry, rcu_head)); | |
133 | } | |
134 | ||
135 | ||
136 | /* Add/merge node to the database of nodes. 'skb' must contain an HSR | |
137 | * supervision frame. | |
138 | * - If the supervision header's MacAddressA field is not yet in the database, | |
139 | * this frame is from an hitherto unknown node - add it to the database. | |
140 | * - If the sender's MAC address is not the same as its MacAddressA address, | |
141 | * the node is using PICS_SUBS (address substitution). Record the sender's | |
142 | * address as the node's MacAddressB. | |
143 | * | |
144 | * This function needs to work even if the sender node has changed one of its | |
145 | * slaves' MAC addresses. In this case, there are four different cases described | |
146 | * by (Addr-changed, received-from) pairs as follows. Note that changing the | |
147 | * SlaveA address is equal to changing the node's own address: | |
148 | * | |
149 | * - (AddrB, SlaveB): The new AddrB will be recorded by PICS_SUBS code since | |
150 | * node == NULL. | |
151 | * - (AddrB, SlaveA): Will work as usual (the AddrB change won't be detected | |
152 | * from this frame). | |
153 | * | |
154 | * - (AddrA, SlaveB): The old node will be found. We need to detect this and | |
155 | * remove the node. | |
156 | * - (AddrA, SlaveA): A new node will be registered (non-PICS_SUBS at first). | |
157 | * The old one will be pruned after HSR_NODE_FORGET_TIME. | |
158 | * | |
159 | * We also need to detect if the sender's SlaveA and SlaveB cables have been | |
160 | * swapped. | |
161 | */ | |
162 | struct node_entry *hsr_merge_node(struct hsr_priv *hsr_priv, | |
163 | struct node_entry *node, | |
164 | struct sk_buff *skb, | |
165 | enum hsr_dev_idx dev_idx) | |
166 | { | |
167 | struct hsr_sup_payload *hsr_sp; | |
168 | struct hsr_ethhdr_sp *hsr_ethsup; | |
169 | int i; | |
170 | unsigned long now; | |
171 | ||
172 | hsr_ethsup = (struct hsr_ethhdr_sp *) skb_mac_header(skb); | |
173 | hsr_sp = (struct hsr_sup_payload *) skb->data; | |
174 | ||
175 | if (node && !ether_addr_equal(node->MacAddressA, hsr_sp->MacAddressA)) { | |
176 | /* Node has changed its AddrA, frame was received from SlaveB */ | |
177 | list_del_rcu(&node->mac_list); | |
178 | call_rcu(&node->rcu_head, node_entry_reclaim); | |
179 | node = NULL; | |
180 | } | |
181 | ||
182 | if (node && (dev_idx == node->AddrB_if) && | |
183 | !ether_addr_equal(node->MacAddressB, hsr_ethsup->ethhdr.h_source)) { | |
184 | /* Cables have been swapped */ | |
185 | list_del_rcu(&node->mac_list); | |
186 | call_rcu(&node->rcu_head, node_entry_reclaim); | |
187 | node = NULL; | |
188 | } | |
189 | ||
190 | if (node && (dev_idx != node->AddrB_if) && | |
191 | (node->AddrB_if != HSR_DEV_NONE) && | |
192 | !ether_addr_equal(node->MacAddressA, hsr_ethsup->ethhdr.h_source)) { | |
193 | /* Cables have been swapped */ | |
194 | list_del_rcu(&node->mac_list); | |
195 | call_rcu(&node->rcu_head, node_entry_reclaim); | |
196 | node = NULL; | |
197 | } | |
198 | ||
199 | if (node) | |
200 | return node; | |
201 | ||
202 | node = find_node_by_AddrA(&hsr_priv->node_db, hsr_sp->MacAddressA); | |
203 | if (node) { | |
204 | /* Node is known, but frame was received from an unknown | |
205 | * address. Node is PICS_SUBS capable; merge its AddrB. | |
206 | */ | |
207 | memcpy(node->MacAddressB, hsr_ethsup->ethhdr.h_source, ETH_ALEN); | |
208 | node->AddrB_if = dev_idx; | |
209 | return node; | |
210 | } | |
211 | ||
212 | node = kzalloc(sizeof(*node), GFP_ATOMIC); | |
213 | if (!node) | |
214 | return NULL; | |
215 | ||
216 | memcpy(node->MacAddressA, hsr_sp->MacAddressA, ETH_ALEN); | |
217 | memcpy(node->MacAddressB, hsr_ethsup->ethhdr.h_source, ETH_ALEN); | |
218 | if (!ether_addr_equal(hsr_sp->MacAddressA, hsr_ethsup->ethhdr.h_source)) | |
219 | node->AddrB_if = dev_idx; | |
220 | else | |
221 | node->AddrB_if = HSR_DEV_NONE; | |
222 | ||
223 | /* We are only interested in time diffs here, so use current jiffies | |
224 | * as initialization. (0 could trigger an spurious ring error warning). | |
225 | */ | |
226 | now = jiffies; | |
227 | for (i = 0; i < HSR_MAX_SLAVE; i++) | |
228 | node->time_in[i] = now; | |
229 | for (i = 0; i < HSR_MAX_DEV; i++) | |
230 | node->seq_out[i] = ntohs(hsr_ethsup->hsr_sup.sequence_nr) - 1; | |
231 | ||
232 | list_add_tail_rcu(&node->mac_list, &hsr_priv->node_db); | |
233 | ||
234 | return node; | |
235 | } | |
236 | ||
237 | ||
238 | /* 'skb' is a frame meant for this host, that is to be passed to upper layers. | |
239 | * | |
240 | * If the frame was sent by a node's B interface, replace the sender | |
241 | * address with that node's "official" address (MacAddressA) so that upper | |
242 | * layers recognize where it came from. | |
243 | */ | |
244 | void hsr_addr_subst_source(struct hsr_priv *hsr_priv, struct sk_buff *skb) | |
245 | { | |
246 | struct ethhdr *ethhdr; | |
247 | struct node_entry *node; | |
248 | ||
249 | if (!skb_mac_header_was_set(skb)) { | |
250 | WARN_ONCE(1, "%s: Mac header not set\n", __func__); | |
251 | return; | |
252 | } | |
253 | ethhdr = (struct ethhdr *) skb_mac_header(skb); | |
254 | ||
255 | rcu_read_lock(); | |
256 | node = find_node_by_AddrB(&hsr_priv->node_db, ethhdr->h_source); | |
257 | if (node) | |
258 | memcpy(ethhdr->h_source, node->MacAddressA, ETH_ALEN); | |
259 | rcu_read_unlock(); | |
260 | } | |
261 | ||
262 | ||
263 | /* 'skb' is a frame meant for another host. | |
264 | * 'hsr_dev_idx' is the HSR index of the outgoing device | |
265 | * | |
266 | * Substitute the target (dest) MAC address if necessary, so the it matches the | |
267 | * recipient interface MAC address, regardless of whether that is the | |
268 | * recipient's A or B interface. | |
269 | * This is needed to keep the packets flowing through switches that learn on | |
270 | * which "side" the different interfaces are. | |
271 | */ | |
272 | void hsr_addr_subst_dest(struct hsr_priv *hsr_priv, struct ethhdr *ethhdr, | |
273 | enum hsr_dev_idx dev_idx) | |
274 | { | |
275 | struct node_entry *node; | |
276 | ||
277 | rcu_read_lock(); | |
278 | node = find_node_by_AddrA(&hsr_priv->node_db, ethhdr->h_dest); | |
279 | if (node && (node->AddrB_if == dev_idx)) | |
280 | memcpy(ethhdr->h_dest, node->MacAddressB, ETH_ALEN); | |
281 | rcu_read_unlock(); | |
282 | } | |
283 | ||
284 | ||
285 | /* seq_nr_after(a, b) - return true if a is after (higher in sequence than) b, | |
286 | * false otherwise. | |
287 | */ | |
288 | static bool seq_nr_after(u16 a, u16 b) | |
289 | { | |
290 | /* Remove inconsistency where | |
291 | * seq_nr_after(a, b) == seq_nr_before(a, b) */ | |
292 | if ((int) b - a == 32768) | |
293 | return false; | |
294 | ||
295 | return (((s16) (b - a)) < 0); | |
296 | } | |
297 | #define seq_nr_before(a, b) seq_nr_after((b), (a)) | |
298 | #define seq_nr_after_or_eq(a, b) (!seq_nr_before((a), (b))) | |
299 | #define seq_nr_before_or_eq(a, b) (!seq_nr_after((a), (b))) | |
300 | ||
301 | ||
302 | void hsr_register_frame_in(struct node_entry *node, enum hsr_dev_idx dev_idx) | |
303 | { | |
304 | if ((dev_idx < 0) || (dev_idx >= HSR_MAX_DEV)) { | |
305 | WARN_ONCE(1, "%s: Invalid dev_idx (%d)\n", __func__, dev_idx); | |
306 | return; | |
307 | } | |
308 | node->time_in[dev_idx] = jiffies; | |
309 | node->time_in_stale[dev_idx] = false; | |
310 | } | |
311 | ||
312 | ||
313 | /* 'skb' is a HSR Ethernet frame (with a HSR tag inserted), with a valid | |
314 | * ethhdr->h_source address and skb->mac_header set. | |
315 | * | |
316 | * Return: | |
317 | * 1 if frame can be shown to have been sent recently on this interface, | |
318 | * 0 otherwise, or | |
319 | * negative error code on error | |
320 | */ | |
321 | int hsr_register_frame_out(struct node_entry *node, enum hsr_dev_idx dev_idx, | |
322 | struct sk_buff *skb) | |
323 | { | |
324 | struct hsr_ethhdr *hsr_ethhdr; | |
325 | u16 sequence_nr; | |
326 | ||
327 | if ((dev_idx < 0) || (dev_idx >= HSR_MAX_DEV)) { | |
328 | WARN_ONCE(1, "%s: Invalid dev_idx (%d)\n", __func__, dev_idx); | |
329 | return -EINVAL; | |
330 | } | |
331 | if (!skb_mac_header_was_set(skb)) { | |
332 | WARN_ONCE(1, "%s: Mac header not set\n", __func__); | |
333 | return -EINVAL; | |
334 | } | |
335 | hsr_ethhdr = (struct hsr_ethhdr *) skb_mac_header(skb); | |
336 | ||
337 | sequence_nr = ntohs(hsr_ethhdr->hsr_tag.sequence_nr); | |
338 | if (seq_nr_before_or_eq(sequence_nr, node->seq_out[dev_idx])) | |
339 | return 1; | |
340 | ||
341 | node->seq_out[dev_idx] = sequence_nr; | |
342 | return 0; | |
343 | } | |
344 | ||
345 | ||
346 | ||
347 | static bool is_late(struct node_entry *node, enum hsr_dev_idx dev_idx) | |
348 | { | |
349 | enum hsr_dev_idx other; | |
350 | ||
351 | if (node->time_in_stale[dev_idx]) | |
352 | return true; | |
353 | ||
354 | if (dev_idx == HSR_DEV_SLAVE_A) | |
355 | other = HSR_DEV_SLAVE_B; | |
356 | else | |
357 | other = HSR_DEV_SLAVE_A; | |
358 | ||
359 | if (node->time_in_stale[other]) | |
360 | return false; | |
361 | ||
362 | if (time_after(node->time_in[other], node->time_in[dev_idx] + | |
363 | msecs_to_jiffies(MAX_SLAVE_DIFF))) | |
364 | return true; | |
365 | ||
366 | return false; | |
367 | } | |
368 | ||
369 | ||
370 | /* Remove stale sequence_nr records. Called by timer every | |
371 | * HSR_LIFE_CHECK_INTERVAL (two seconds or so). | |
372 | */ | |
373 | void hsr_prune_nodes(struct hsr_priv *hsr_priv) | |
374 | { | |
375 | struct node_entry *node; | |
376 | unsigned long timestamp; | |
377 | unsigned long time_a, time_b; | |
378 | ||
379 | rcu_read_lock(); | |
380 | list_for_each_entry_rcu(node, &hsr_priv->node_db, mac_list) { | |
381 | /* Shorthand */ | |
382 | time_a = node->time_in[HSR_DEV_SLAVE_A]; | |
383 | time_b = node->time_in[HSR_DEV_SLAVE_B]; | |
384 | ||
385 | /* Check for timestamps old enough to risk wrap-around */ | |
386 | if (time_after(jiffies, time_a + MAX_JIFFY_OFFSET/2)) | |
387 | node->time_in_stale[HSR_DEV_SLAVE_A] = true; | |
388 | if (time_after(jiffies, time_b + MAX_JIFFY_OFFSET/2)) | |
389 | node->time_in_stale[HSR_DEV_SLAVE_B] = true; | |
390 | ||
391 | /* Get age of newest frame from node. | |
392 | * At least one time_in is OK here; nodes get pruned long | |
393 | * before both time_ins can get stale | |
394 | */ | |
395 | timestamp = time_a; | |
396 | if (node->time_in_stale[HSR_DEV_SLAVE_A] || | |
397 | (!node->time_in_stale[HSR_DEV_SLAVE_B] && | |
398 | time_after(time_b, time_a))) | |
399 | timestamp = time_b; | |
400 | ||
401 | /* Warn of ring error only as long as we get frames at all */ | |
402 | if (time_is_after_jiffies(timestamp + | |
403 | msecs_to_jiffies(1.5*MAX_SLAVE_DIFF))) { | |
404 | ||
405 | if (is_late(node, HSR_DEV_SLAVE_A)) | |
406 | hsr_nl_ringerror(hsr_priv, node->MacAddressA, | |
407 | HSR_DEV_SLAVE_A); | |
408 | else if (is_late(node, HSR_DEV_SLAVE_B)) | |
409 | hsr_nl_ringerror(hsr_priv, node->MacAddressA, | |
410 | HSR_DEV_SLAVE_B); | |
411 | } | |
412 | ||
413 | /* Prune old entries */ | |
414 | if (time_is_before_jiffies(timestamp + | |
415 | msecs_to_jiffies(HSR_NODE_FORGET_TIME))) { | |
416 | hsr_nl_nodedown(hsr_priv, node->MacAddressA); | |
417 | list_del_rcu(&node->mac_list); | |
418 | /* Note that we need to free this entry later: */ | |
419 | call_rcu(&node->rcu_head, node_entry_reclaim); | |
420 | } | |
421 | } | |
422 | rcu_read_unlock(); | |
423 | } | |
424 | ||
425 | ||
426 | void *hsr_get_next_node(struct hsr_priv *hsr_priv, void *_pos, | |
427 | unsigned char addr[ETH_ALEN]) | |
428 | { | |
429 | struct node_entry *node; | |
430 | ||
431 | if (!_pos) { | |
432 | node = list_first_or_null_rcu(&hsr_priv->node_db, | |
433 | struct node_entry, mac_list); | |
434 | if (node) | |
435 | memcpy(addr, node->MacAddressA, ETH_ALEN); | |
436 | return node; | |
437 | } | |
438 | ||
439 | node = _pos; | |
440 | list_for_each_entry_continue_rcu(node, &hsr_priv->node_db, mac_list) { | |
441 | memcpy(addr, node->MacAddressA, ETH_ALEN); | |
442 | return node; | |
443 | } | |
444 | ||
445 | return NULL; | |
446 | } | |
447 | ||
448 | ||
449 | int hsr_get_node_data(struct hsr_priv *hsr_priv, | |
450 | const unsigned char *addr, | |
451 | unsigned char addr_b[ETH_ALEN], | |
452 | unsigned int *addr_b_ifindex, | |
453 | int *if1_age, | |
454 | u16 *if1_seq, | |
455 | int *if2_age, | |
456 | u16 *if2_seq) | |
457 | { | |
458 | struct node_entry *node; | |
459 | unsigned long tdiff; | |
460 | ||
461 | ||
462 | rcu_read_lock(); | |
463 | node = find_node_by_AddrA(&hsr_priv->node_db, addr); | |
464 | if (!node) { | |
465 | rcu_read_unlock(); | |
466 | return -ENOENT; /* No such entry */ | |
467 | } | |
468 | ||
469 | memcpy(addr_b, node->MacAddressB, ETH_ALEN); | |
470 | ||
471 | tdiff = jiffies - node->time_in[HSR_DEV_SLAVE_A]; | |
472 | if (node->time_in_stale[HSR_DEV_SLAVE_A]) | |
473 | *if1_age = INT_MAX; | |
474 | #if HZ <= MSEC_PER_SEC | |
475 | else if (tdiff > msecs_to_jiffies(INT_MAX)) | |
476 | *if1_age = INT_MAX; | |
477 | #endif | |
478 | else | |
479 | *if1_age = jiffies_to_msecs(tdiff); | |
480 | ||
481 | tdiff = jiffies - node->time_in[HSR_DEV_SLAVE_B]; | |
482 | if (node->time_in_stale[HSR_DEV_SLAVE_B]) | |
483 | *if2_age = INT_MAX; | |
484 | #if HZ <= MSEC_PER_SEC | |
485 | else if (tdiff > msecs_to_jiffies(INT_MAX)) | |
486 | *if2_age = INT_MAX; | |
487 | #endif | |
488 | else | |
489 | *if2_age = jiffies_to_msecs(tdiff); | |
490 | ||
491 | /* Present sequence numbers as if they were incoming on interface */ | |
492 | *if1_seq = node->seq_out[HSR_DEV_SLAVE_B]; | |
493 | *if2_seq = node->seq_out[HSR_DEV_SLAVE_A]; | |
494 | ||
495 | if ((node->AddrB_if != HSR_DEV_NONE) && hsr_priv->slave[node->AddrB_if]) | |
496 | *addr_b_ifindex = hsr_priv->slave[node->AddrB_if]->ifindex; | |
497 | else | |
498 | *addr_b_ifindex = -1; | |
499 | ||
500 | rcu_read_unlock(); | |
501 | ||
502 | return 0; | |
503 | } |