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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 | ||
f421436a AB |
130 | |
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 | */ | |
157 | struct 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); | |
1aee6cc2 | 173 | kfree_rcu(node, rcu_head); |
f421436a AB |
174 | 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); | |
1aee6cc2 | 181 | kfree_rcu(node, rcu_head); |
f421436a AB |
182 | 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); | |
1aee6cc2 | 190 | kfree_rcu(node, rcu_head); |
f421436a AB |
191 | 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 | */ | |
239 | void 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 | */ | |
267 | void 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 | */ | |
283 | static bool seq_nr_after(u16 a, u16 b) | |
284 | { | |
285 | /* Remove inconsistency where | |
213e3bc7 AB |
286 | * seq_nr_after(a, b) == seq_nr_before(a, b) |
287 | */ | |
f421436a AB |
288 | 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 | ||
298 | void 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 | */ | |
317 | int 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 | ||
343 | static 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 | */ | |
369 | void 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: */ | |
1aee6cc2 | 415 | kfree_rcu(node, rcu_head); |
f421436a AB |
416 | } |
417 | } | |
418 | rcu_read_unlock(); | |
419 | } | |
420 | ||
421 | ||
422 | void *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 | ||
445 | int 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 | } |