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 /* TODO: use hash lists for mac addresses (linux/jhash.h)? */
23
24 /* seq_nr_after(a, b) - return true if a is after (higher in sequence than) b,
25 * false otherwise.
26 */
seq_nr_after(u16 a,u16 b)27 static bool seq_nr_after(u16 a, u16 b)
28 {
29 /* Remove inconsistency where
30 * seq_nr_after(a, b) == seq_nr_before(a, b)
31 */
32 if ((int)b - a == 32768)
33 return false;
34
35 return (((s16)(b - a)) < 0);
36 }
37
38 #define seq_nr_before(a, b) seq_nr_after((b), (a))
39 #define seq_nr_before_or_eq(a, b) (!seq_nr_after((a), (b)))
40
hsr_addr_is_self(struct hsr_priv * hsr,unsigned char * addr)41 bool hsr_addr_is_self(struct hsr_priv *hsr, unsigned char *addr)
42 {
43 struct hsr_node *node;
44
45 node = list_first_or_null_rcu(&hsr->self_node_db, struct hsr_node,
46 mac_list);
47 if (!node) {
48 WARN_ONCE(1, "HSR: No self node\n");
49 return false;
50 }
51
52 if (ether_addr_equal(addr, node->macaddress_A))
53 return true;
54 if (ether_addr_equal(addr, node->macaddress_B))
55 return true;
56
57 return false;
58 }
59
60 /* Search for mac entry. Caller must hold rcu read lock.
61 */
find_node_by_addr_A(struct list_head * node_db,const unsigned char addr[ETH_ALEN])62 static struct hsr_node *find_node_by_addr_A(struct list_head *node_db,
63 const unsigned char addr[ETH_ALEN])
64 {
65 struct hsr_node *node;
66
67 list_for_each_entry_rcu(node, node_db, mac_list) {
68 if (ether_addr_equal(node->macaddress_A, addr))
69 return node;
70 }
71
72 return NULL;
73 }
74
75 /* Helper for device init; the self_node_db is used in hsr_rcv() to recognize
76 * frames from self that's been looped over the HSR ring.
77 */
hsr_create_self_node(struct hsr_priv * hsr,unsigned char addr_a[ETH_ALEN],unsigned char addr_b[ETH_ALEN])78 int hsr_create_self_node(struct hsr_priv *hsr,
79 unsigned char addr_a[ETH_ALEN],
80 unsigned char addr_b[ETH_ALEN])
81 {
82 struct list_head *self_node_db = &hsr->self_node_db;
83 struct hsr_node *node, *oldnode;
84
85 node = kmalloc(sizeof(*node), GFP_KERNEL);
86 if (!node)
87 return -ENOMEM;
88
89 ether_addr_copy(node->macaddress_A, addr_a);
90 ether_addr_copy(node->macaddress_B, addr_b);
91
92 spin_lock_bh(&hsr->list_lock);
93 oldnode = list_first_or_null_rcu(self_node_db,
94 struct hsr_node, mac_list);
95 if (oldnode) {
96 list_replace_rcu(&oldnode->mac_list, &node->mac_list);
97 spin_unlock_bh(&hsr->list_lock);
98 kfree_rcu(oldnode, rcu_head);
99 } else {
100 list_add_tail_rcu(&node->mac_list, self_node_db);
101 spin_unlock_bh(&hsr->list_lock);
102 }
103
104 return 0;
105 }
106
hsr_del_self_node(struct hsr_priv * hsr)107 void hsr_del_self_node(struct hsr_priv *hsr)
108 {
109 struct list_head *self_node_db = &hsr->self_node_db;
110 struct hsr_node *node;
111
112 spin_lock_bh(&hsr->list_lock);
113 node = list_first_or_null_rcu(self_node_db, struct hsr_node, mac_list);
114 if (node) {
115 list_del_rcu(&node->mac_list);
116 kfree_rcu(node, rcu_head);
117 }
118 spin_unlock_bh(&hsr->list_lock);
119 }
120
hsr_del_nodes(struct list_head * node_db)121 void hsr_del_nodes(struct list_head *node_db)
122 {
123 struct hsr_node *node;
124 struct hsr_node *tmp;
125
126 list_for_each_entry_safe(node, tmp, node_db, mac_list)
127 kfree(node);
128 }
129
prp_handle_san_frame(bool san,enum hsr_port_type port,struct hsr_node * node)130 void prp_handle_san_frame(bool san, enum hsr_port_type port,
131 struct hsr_node *node)
132 {
133 /* Mark if the SAN node is over LAN_A or LAN_B */
134 if (port == HSR_PT_SLAVE_A) {
135 node->san_a = true;
136 return;
137 }
138
139 if (port == HSR_PT_SLAVE_B)
140 node->san_b = true;
141 }
142
143 /* Allocate an hsr_node and add it to node_db. 'addr' is the node's address_A;
144 * seq_out is used to initialize filtering of outgoing duplicate frames
145 * originating from the newly added node.
146 */
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)147 static struct hsr_node *hsr_add_node(struct hsr_priv *hsr,
148 struct list_head *node_db,
149 unsigned char addr[],
150 u16 seq_out, bool san,
151 enum hsr_port_type rx_port)
152 {
153 struct hsr_node *new_node, *node;
154 unsigned long now;
155 int i;
156
157 new_node = kzalloc(sizeof(*new_node), GFP_ATOMIC);
158 if (!new_node)
159 return NULL;
160
161 ether_addr_copy(new_node->macaddress_A, addr);
162 spin_lock_init(&new_node->seq_out_lock);
163
164 /* We are only interested in time diffs here, so use current jiffies
165 * as initialization. (0 could trigger an spurious ring error warning).
166 */
167 now = jiffies;
168 for (i = 0; i < HSR_PT_PORTS; i++) {
169 new_node->time_in[i] = now;
170 new_node->time_out[i] = now;
171 }
172 for (i = 0; i < HSR_PT_PORTS; i++)
173 new_node->seq_out[i] = seq_out;
174
175 if (san && hsr->proto_ops->handle_san_frame)
176 hsr->proto_ops->handle_san_frame(san, rx_port, new_node);
177
178 spin_lock_bh(&hsr->list_lock);
179 list_for_each_entry_rcu(node, node_db, mac_list,
180 lockdep_is_held(&hsr->list_lock)) {
181 if (ether_addr_equal(node->macaddress_A, addr))
182 goto out;
183 if (ether_addr_equal(node->macaddress_B, addr))
184 goto out;
185 }
186 list_add_tail_rcu(&new_node->mac_list, node_db);
187 spin_unlock_bh(&hsr->list_lock);
188 return new_node;
189 out:
190 spin_unlock_bh(&hsr->list_lock);
191 kfree(new_node);
192 return node;
193 }
194
prp_update_san_info(struct hsr_node * node,bool is_sup)195 void prp_update_san_info(struct hsr_node *node, bool is_sup)
196 {
197 if (!is_sup)
198 return;
199
200 node->san_a = false;
201 node->san_b = false;
202 }
203
204 /* Get the hsr_node from which 'skb' was sent.
205 */
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)206 struct hsr_node *hsr_get_node(struct hsr_port *port, struct list_head *node_db,
207 struct sk_buff *skb, bool is_sup,
208 enum hsr_port_type rx_port)
209 {
210 struct hsr_priv *hsr = port->hsr;
211 struct hsr_node *node;
212 struct ethhdr *ethhdr;
213 struct prp_rct *rct;
214 bool san = false;
215 u16 seq_out;
216
217 if (!skb_mac_header_was_set(skb))
218 return NULL;
219
220 ethhdr = (struct ethhdr *)skb_mac_header(skb);
221
222 list_for_each_entry_rcu(node, node_db, mac_list) {
223 if (ether_addr_equal(node->macaddress_A, ethhdr->h_source)) {
224 if (hsr->proto_ops->update_san_info)
225 hsr->proto_ops->update_san_info(node, is_sup);
226 return node;
227 }
228 if (ether_addr_equal(node->macaddress_B, ethhdr->h_source)) {
229 if (hsr->proto_ops->update_san_info)
230 hsr->proto_ops->update_san_info(node, is_sup);
231 return node;
232 }
233 }
234
235 /* Everyone may create a node entry, connected node to a HSR/PRP
236 * device.
237 */
238 if (ethhdr->h_proto == htons(ETH_P_PRP) ||
239 ethhdr->h_proto == htons(ETH_P_HSR)) {
240 /* Use the existing sequence_nr from the tag as starting point
241 * for filtering duplicate frames.
242 */
243 seq_out = hsr_get_skb_sequence_nr(skb) - 1;
244 } else {
245 rct = skb_get_PRP_rct(skb);
246 if (rct && prp_check_lsdu_size(skb, rct, is_sup)) {
247 seq_out = prp_get_skb_sequence_nr(rct);
248 } else {
249 if (rx_port != HSR_PT_MASTER)
250 san = true;
251 seq_out = HSR_SEQNR_START;
252 }
253 }
254
255 return hsr_add_node(hsr, node_db, ethhdr->h_source, seq_out,
256 san, rx_port);
257 }
258
259 /* Use the Supervision frame's info about an eventual macaddress_B for merging
260 * nodes that has previously had their macaddress_B registered as a separate
261 * node.
262 */
hsr_handle_sup_frame(struct hsr_frame_info * frame)263 void hsr_handle_sup_frame(struct hsr_frame_info *frame)
264 {
265 struct hsr_node *node_curr = frame->node_src;
266 struct hsr_port *port_rcv = frame->port_rcv;
267 struct hsr_priv *hsr = port_rcv->hsr;
268 struct hsr_sup_payload *hsr_sp;
269 struct hsr_node *node_real;
270 struct sk_buff *skb = NULL;
271 struct list_head *node_db;
272 struct ethhdr *ethhdr;
273 int i;
274
275 /* Here either frame->skb_hsr or frame->skb_prp should be
276 * valid as supervision frame always will have protocol
277 * header info.
278 */
279 if (frame->skb_hsr)
280 skb = frame->skb_hsr;
281 else if (frame->skb_prp)
282 skb = frame->skb_prp;
283 else if (frame->skb_std)
284 skb = frame->skb_std;
285 if (!skb)
286 return;
287
288 ethhdr = (struct ethhdr *)skb_mac_header(skb);
289
290 /* Leave the ethernet header. */
291 skb_pull(skb, sizeof(struct ethhdr));
292
293 /* And leave the HSR tag. */
294 if (ethhdr->h_proto == htons(ETH_P_HSR))
295 skb_pull(skb, sizeof(struct hsr_tag));
296
297 /* And leave the HSR sup tag. */
298 skb_pull(skb, sizeof(struct hsr_sup_tag));
299
300 hsr_sp = (struct hsr_sup_payload *)skb->data;
301
302 /* Merge node_curr (registered on macaddress_B) into node_real */
303 node_db = &port_rcv->hsr->node_db;
304 node_real = find_node_by_addr_A(node_db, hsr_sp->macaddress_A);
305 if (!node_real)
306 /* No frame received from AddrA of this node yet */
307 node_real = hsr_add_node(hsr, node_db, hsr_sp->macaddress_A,
308 HSR_SEQNR_START - 1, true,
309 port_rcv->type);
310 if (!node_real)
311 goto done; /* No mem */
312 if (node_real == node_curr)
313 /* Node has already been merged */
314 goto done;
315
316 ether_addr_copy(node_real->macaddress_B, ethhdr->h_source);
317 spin_lock_bh(&node_real->seq_out_lock);
318 for (i = 0; i < HSR_PT_PORTS; i++) {
319 if (!node_curr->time_in_stale[i] &&
320 time_after(node_curr->time_in[i], node_real->time_in[i])) {
321 node_real->time_in[i] = node_curr->time_in[i];
322 node_real->time_in_stale[i] =
323 node_curr->time_in_stale[i];
324 }
325 if (seq_nr_after(node_curr->seq_out[i], node_real->seq_out[i]))
326 node_real->seq_out[i] = node_curr->seq_out[i];
327 }
328 spin_unlock_bh(&node_real->seq_out_lock);
329 node_real->addr_B_port = port_rcv->type;
330
331 spin_lock_bh(&hsr->list_lock);
332 if (!node_curr->removed) {
333 list_del_rcu(&node_curr->mac_list);
334 node_curr->removed = true;
335 kfree_rcu(node_curr, rcu_head);
336 }
337 spin_unlock_bh(&hsr->list_lock);
338
339 done:
340 /* PRP uses v0 header */
341 if (ethhdr->h_proto == htons(ETH_P_HSR))
342 skb_push(skb, sizeof(struct hsrv1_ethhdr_sp));
343 else
344 skb_push(skb, sizeof(struct hsrv0_ethhdr_sp));
345 }
346
347 /* 'skb' is a frame meant for this host, that is to be passed to upper layers.
348 *
349 * If the frame was sent by a node's B interface, replace the source
350 * address with that node's "official" address (macaddress_A) so that upper
351 * layers recognize where it came from.
352 */
hsr_addr_subst_source(struct hsr_node * node,struct sk_buff * skb)353 void hsr_addr_subst_source(struct hsr_node *node, struct sk_buff *skb)
354 {
355 if (!skb_mac_header_was_set(skb)) {
356 WARN_ONCE(1, "%s: Mac header not set\n", __func__);
357 return;
358 }
359
360 memcpy(ð_hdr(skb)->h_source, node->macaddress_A, ETH_ALEN);
361 }
362
363 /* 'skb' is a frame meant for another host.
364 * 'port' is the outgoing interface
365 *
366 * Substitute the target (dest) MAC address if necessary, so the it matches the
367 * recipient interface MAC address, regardless of whether that is the
368 * recipient's A or B interface.
369 * This is needed to keep the packets flowing through switches that learn on
370 * which "side" the different interfaces are.
371 */
hsr_addr_subst_dest(struct hsr_node * node_src,struct sk_buff * skb,struct hsr_port * port)372 void hsr_addr_subst_dest(struct hsr_node *node_src, struct sk_buff *skb,
373 struct hsr_port *port)
374 {
375 struct hsr_node *node_dst;
376
377 if (!skb_mac_header_was_set(skb)) {
378 WARN_ONCE(1, "%s: Mac header not set\n", __func__);
379 return;
380 }
381
382 if (!is_unicast_ether_addr(eth_hdr(skb)->h_dest))
383 return;
384
385 node_dst = find_node_by_addr_A(&port->hsr->node_db,
386 eth_hdr(skb)->h_dest);
387 if (!node_dst) {
388 if (port->hsr->prot_version != PRP_V1 && net_ratelimit())
389 netdev_err(skb->dev, "%s: Unknown node\n", __func__);
390 return;
391 }
392 if (port->type != node_dst->addr_B_port)
393 return;
394
395 if (is_valid_ether_addr(node_dst->macaddress_B))
396 ether_addr_copy(eth_hdr(skb)->h_dest, node_dst->macaddress_B);
397 }
398
hsr_register_frame_in(struct hsr_node * node,struct hsr_port * port,u16 sequence_nr)399 void hsr_register_frame_in(struct hsr_node *node, struct hsr_port *port,
400 u16 sequence_nr)
401 {
402 /* Don't register incoming frames without a valid sequence number. This
403 * ensures entries of restarted nodes gets pruned so that they can
404 * re-register and resume communications.
405 */
406 if (!(port->dev->features & NETIF_F_HW_HSR_TAG_RM) &&
407 seq_nr_before(sequence_nr, node->seq_out[port->type]))
408 return;
409
410 node->time_in[port->type] = jiffies;
411 node->time_in_stale[port->type] = false;
412 }
413
414 /* 'skb' is a HSR Ethernet frame (with a HSR tag inserted), with a valid
415 * ethhdr->h_source address and skb->mac_header set.
416 *
417 * Return:
418 * 1 if frame can be shown to have been sent recently on this interface,
419 * 0 otherwise, or
420 * negative error code on error
421 */
hsr_register_frame_out(struct hsr_port * port,struct hsr_node * node,u16 sequence_nr)422 int hsr_register_frame_out(struct hsr_port *port, struct hsr_node *node,
423 u16 sequence_nr)
424 {
425 spin_lock_bh(&node->seq_out_lock);
426 if (seq_nr_before_or_eq(sequence_nr, node->seq_out[port->type]) &&
427 time_is_after_jiffies(node->time_out[port->type] +
428 msecs_to_jiffies(HSR_ENTRY_FORGET_TIME))) {
429 spin_unlock_bh(&node->seq_out_lock);
430 return 1;
431 }
432
433 node->time_out[port->type] = jiffies;
434 node->seq_out[port->type] = sequence_nr;
435 spin_unlock_bh(&node->seq_out_lock);
436 return 0;
437 }
438
get_late_port(struct hsr_priv * hsr,struct hsr_node * node)439 static struct hsr_port *get_late_port(struct hsr_priv *hsr,
440 struct hsr_node *node)
441 {
442 if (node->time_in_stale[HSR_PT_SLAVE_A])
443 return hsr_port_get_hsr(hsr, HSR_PT_SLAVE_A);
444 if (node->time_in_stale[HSR_PT_SLAVE_B])
445 return hsr_port_get_hsr(hsr, HSR_PT_SLAVE_B);
446
447 if (time_after(node->time_in[HSR_PT_SLAVE_B],
448 node->time_in[HSR_PT_SLAVE_A] +
449 msecs_to_jiffies(MAX_SLAVE_DIFF)))
450 return hsr_port_get_hsr(hsr, HSR_PT_SLAVE_A);
451 if (time_after(node->time_in[HSR_PT_SLAVE_A],
452 node->time_in[HSR_PT_SLAVE_B] +
453 msecs_to_jiffies(MAX_SLAVE_DIFF)))
454 return hsr_port_get_hsr(hsr, HSR_PT_SLAVE_B);
455
456 return NULL;
457 }
458
459 /* Remove stale sequence_nr records. Called by timer every
460 * HSR_LIFE_CHECK_INTERVAL (two seconds or so).
461 */
hsr_prune_nodes(struct timer_list * t)462 void hsr_prune_nodes(struct timer_list *t)
463 {
464 struct hsr_priv *hsr = from_timer(hsr, t, prune_timer);
465 struct hsr_node *node;
466 struct hsr_node *tmp;
467 struct hsr_port *port;
468 unsigned long timestamp;
469 unsigned long time_a, time_b;
470
471 spin_lock_bh(&hsr->list_lock);
472 list_for_each_entry_safe(node, tmp, &hsr->node_db, mac_list) {
473 /* Don't prune own node. Neither time_in[HSR_PT_SLAVE_A]
474 * nor time_in[HSR_PT_SLAVE_B], will ever be updated for
475 * the master port. Thus the master node will be repeatedly
476 * pruned leading to packet loss.
477 */
478 if (hsr_addr_is_self(hsr, node->macaddress_A))
479 continue;
480
481 /* Shorthand */
482 time_a = node->time_in[HSR_PT_SLAVE_A];
483 time_b = node->time_in[HSR_PT_SLAVE_B];
484
485 /* Check for timestamps old enough to risk wrap-around */
486 if (time_after(jiffies, time_a + MAX_JIFFY_OFFSET / 2))
487 node->time_in_stale[HSR_PT_SLAVE_A] = true;
488 if (time_after(jiffies, time_b + MAX_JIFFY_OFFSET / 2))
489 node->time_in_stale[HSR_PT_SLAVE_B] = true;
490
491 /* Get age of newest frame from node.
492 * At least one time_in is OK here; nodes get pruned long
493 * before both time_ins can get stale
494 */
495 timestamp = time_a;
496 if (node->time_in_stale[HSR_PT_SLAVE_A] ||
497 (!node->time_in_stale[HSR_PT_SLAVE_B] &&
498 time_after(time_b, time_a)))
499 timestamp = time_b;
500
501 /* Warn of ring error only as long as we get frames at all */
502 if (time_is_after_jiffies(timestamp +
503 msecs_to_jiffies(1.5 * MAX_SLAVE_DIFF))) {
504 rcu_read_lock();
505 port = get_late_port(hsr, node);
506 if (port)
507 hsr_nl_ringerror(hsr, node->macaddress_A, port);
508 rcu_read_unlock();
509 }
510
511 /* Prune old entries */
512 if (time_is_before_jiffies(timestamp +
513 msecs_to_jiffies(HSR_NODE_FORGET_TIME))) {
514 hsr_nl_nodedown(hsr, node->macaddress_A);
515 if (!node->removed) {
516 list_del_rcu(&node->mac_list);
517 node->removed = true;
518 /* Note that we need to free this entry later: */
519 kfree_rcu(node, rcu_head);
520 }
521 }
522 }
523 spin_unlock_bh(&hsr->list_lock);
524
525 /* Restart timer */
526 mod_timer(&hsr->prune_timer,
527 jiffies + msecs_to_jiffies(PRUNE_PERIOD));
528 }
529
hsr_get_next_node(struct hsr_priv * hsr,void * _pos,unsigned char addr[ETH_ALEN])530 void *hsr_get_next_node(struct hsr_priv *hsr, void *_pos,
531 unsigned char addr[ETH_ALEN])
532 {
533 struct hsr_node *node;
534
535 if (!_pos) {
536 node = list_first_or_null_rcu(&hsr->node_db,
537 struct hsr_node, mac_list);
538 if (node)
539 ether_addr_copy(addr, node->macaddress_A);
540 return node;
541 }
542
543 node = _pos;
544 list_for_each_entry_continue_rcu(node, &hsr->node_db, mac_list) {
545 ether_addr_copy(addr, node->macaddress_A);
546 return node;
547 }
548
549 return NULL;
550 }
551
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)552 int hsr_get_node_data(struct hsr_priv *hsr,
553 const unsigned char *addr,
554 unsigned char addr_b[ETH_ALEN],
555 unsigned int *addr_b_ifindex,
556 int *if1_age,
557 u16 *if1_seq,
558 int *if2_age,
559 u16 *if2_seq)
560 {
561 struct hsr_node *node;
562 struct hsr_port *port;
563 unsigned long tdiff;
564
565 node = find_node_by_addr_A(&hsr->node_db, addr);
566 if (!node)
567 return -ENOENT;
568
569 ether_addr_copy(addr_b, node->macaddress_B);
570
571 tdiff = jiffies - node->time_in[HSR_PT_SLAVE_A];
572 if (node->time_in_stale[HSR_PT_SLAVE_A])
573 *if1_age = INT_MAX;
574 #if HZ <= MSEC_PER_SEC
575 else if (tdiff > msecs_to_jiffies(INT_MAX))
576 *if1_age = INT_MAX;
577 #endif
578 else
579 *if1_age = jiffies_to_msecs(tdiff);
580
581 tdiff = jiffies - node->time_in[HSR_PT_SLAVE_B];
582 if (node->time_in_stale[HSR_PT_SLAVE_B])
583 *if2_age = INT_MAX;
584 #if HZ <= MSEC_PER_SEC
585 else if (tdiff > msecs_to_jiffies(INT_MAX))
586 *if2_age = INT_MAX;
587 #endif
588 else
589 *if2_age = jiffies_to_msecs(tdiff);
590
591 /* Present sequence numbers as if they were incoming on interface */
592 *if1_seq = node->seq_out[HSR_PT_SLAVE_B];
593 *if2_seq = node->seq_out[HSR_PT_SLAVE_A];
594
595 if (node->addr_B_port != HSR_PT_NONE) {
596 port = hsr_port_get_hsr(hsr, node->addr_B_port);
597 *addr_b_ifindex = port->dev->ifindex;
598 } else {
599 *addr_b_ifindex = -1;
600 }
601
602 return 0;
603 }
604