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1/* Copyright 2011-2014 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 * 2011-2014 Arvid Brodin, arvid.brodin@alten.se
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 hsr_node {
27 struct list_head mac_list;
28 unsigned char MacAddressA[ETH_ALEN];
29 unsigned char MacAddressB[ETH_ALEN];
30 /* Local slave through which AddrB frames are received from this node */
31 enum hsr_port_type AddrB_port;
32 unsigned long time_in[HSR_PT_PORTS];
33 bool time_in_stale[HSR_PT_PORTS];
34 u16 seq_out[HSR_PT_PORTS];
35 struct rcu_head rcu_head;
36};
37
38
39/* TODO: use hash lists for mac addresses (linux/jhash.h)? */
40
41
42/* seq_nr_after(a, b) - return true if a is after (higher in sequence than) b,
43 * false otherwise.
44 */
45static bool seq_nr_after(u16 a, u16 b)
46{
47 /* Remove inconsistency where
48 * seq_nr_after(a, b) == seq_nr_before(a, b)
49 */
50 if ((int) b - a == 32768)
51 return false;
52
53 return (((s16) (b - a)) < 0);
54}
55#define seq_nr_before(a, b) seq_nr_after((b), (a))
56#define seq_nr_after_or_eq(a, b) (!seq_nr_before((a), (b)))
57#define seq_nr_before_or_eq(a, b) (!seq_nr_after((a), (b)))
58
59
60bool hsr_addr_is_self(struct hsr_priv *hsr, unsigned char *addr)
61{
62 struct hsr_node *node;
63
64 node = list_first_or_null_rcu(&hsr->self_node_db, struct hsr_node,
65 mac_list);
66 if (!node) {
67 WARN_ONCE(1, "HSR: No self node\n");
68 return false;
69 }
70
71 if (ether_addr_equal(addr, node->MacAddressA))
72 return true;
73 if (ether_addr_equal(addr, node->MacAddressB))
74 return true;
75
76 return false;
77}
78
79/* Search for mac entry. Caller must hold rcu read lock.
80 */
81static struct hsr_node *find_node_by_AddrA(struct list_head *node_db,
82 const unsigned char addr[ETH_ALEN])
83{
84 struct hsr_node *node;
85
86 list_for_each_entry_rcu(node, node_db, mac_list) {
87 if (ether_addr_equal(node->MacAddressA, addr))
88 return node;
89 }
90
91 return NULL;
92}
93
94
95/* Helper for device init; the self_node_db is used in hsr_rcv() to recognize
96 * frames from self that's been looped over the HSR ring.
97 */
98int hsr_create_self_node(struct list_head *self_node_db,
99 unsigned char addr_a[ETH_ALEN],
100 unsigned char addr_b[ETH_ALEN])
101{
102 struct hsr_node *node, *oldnode;
103
104 node = kmalloc(sizeof(*node), GFP_KERNEL);
105 if (!node)
106 return -ENOMEM;
107
108 ether_addr_copy(node->MacAddressA, addr_a);
109 ether_addr_copy(node->MacAddressB, addr_b);
110
111 rcu_read_lock();
112 oldnode = list_first_or_null_rcu(self_node_db,
113 struct hsr_node, mac_list);
114 if (oldnode) {
115 list_replace_rcu(&oldnode->mac_list, &node->mac_list);
116 rcu_read_unlock();
117 synchronize_rcu();
118 kfree(oldnode);
119 } else {
120 rcu_read_unlock();
121 list_add_tail_rcu(&node->mac_list, self_node_db);
122 }
123
124 return 0;
125}
126
127
128/* Allocate an hsr_node and add it to node_db. 'addr' is the node's AddressA;
129 * seq_out is used to initialize filtering of outgoing duplicate frames
130 * originating from the newly added node.
131 */
132struct hsr_node *hsr_add_node(struct list_head *node_db, unsigned char addr[],
133 u16 seq_out)
134{
135 struct hsr_node *node;
136 unsigned long now;
137 int i;
138
139 node = kzalloc(sizeof(*node), GFP_ATOMIC);
140 if (!node)
141 return NULL;
142
143 ether_addr_copy(node->MacAddressA, addr);
144
145 /* We are only interested in time diffs here, so use current jiffies
146 * as initialization. (0 could trigger an spurious ring error warning).
147 */
148 now = jiffies;
149 for (i = 0; i < HSR_PT_PORTS; i++)
150 node->time_in[i] = now;
151 for (i = 0; i < HSR_PT_PORTS; i++)
152 node->seq_out[i] = seq_out;
153
154 list_add_tail_rcu(&node->mac_list, node_db);
155
156 return node;
157}
158
159/* Get the hsr_node from which 'skb' was sent.
160 */
161struct hsr_node *hsr_get_node(struct hsr_port *port, struct sk_buff *skb,
162 bool is_sup)
163{
164 struct list_head *node_db = &port->hsr->node_db;
165 struct hsr_node *node;
166 struct ethhdr *ethhdr;
167 u16 seq_out;
168
169 if (!skb_mac_header_was_set(skb))
170 return NULL;
171
172 ethhdr = (struct ethhdr *) skb_mac_header(skb);
173
174 list_for_each_entry_rcu(node, node_db, mac_list) {
175 if (ether_addr_equal(node->MacAddressA, ethhdr->h_source))
176 return node;
177 if (ether_addr_equal(node->MacAddressB, ethhdr->h_source))
178 return node;
179 }
180
181 /* Everyone may create a node entry, connected node to a HSR device. */
182
183 if (ethhdr->h_proto == htons(ETH_P_PRP)
184 || ethhdr->h_proto == htons(ETH_P_HSR)) {
185 /* Use the existing sequence_nr from the tag as starting point
186 * for filtering duplicate frames.
187 */
188 seq_out = hsr_get_skb_sequence_nr(skb) - 1;
189 } else {
190 /* this is called also for frames from master port and
191 * so warn only for non master ports
192 */
193 if (port->type != HSR_PT_MASTER)
194 WARN_ONCE(1, "%s: Non-HSR frame\n", __func__);
195 seq_out = HSR_SEQNR_START;
196 }
197
198 return hsr_add_node(node_db, ethhdr->h_source, seq_out);
199}
200
201/* Use the Supervision frame's info about an eventual MacAddressB for merging
202 * nodes that has previously had their MacAddressB registered as a separate
203 * node.
204 */
205void hsr_handle_sup_frame(struct sk_buff *skb, struct hsr_node *node_curr,
206 struct hsr_port *port_rcv)
207{
208 struct ethhdr *ethhdr;
209 struct hsr_node *node_real;
210 struct hsr_sup_payload *hsr_sp;
211 struct list_head *node_db;
212 int i;
213
214 ethhdr = (struct ethhdr *) skb_mac_header(skb);
215
216 /* Leave the ethernet header. */
217 skb_pull(skb, sizeof(struct ethhdr));
218
219 /* And leave the HSR tag. */
220 if (ethhdr->h_proto == htons(ETH_P_HSR))
221 skb_pull(skb, sizeof(struct hsr_tag));
222
223 /* And leave the HSR sup tag. */
224 skb_pull(skb, sizeof(struct hsr_sup_tag));
225
226 hsr_sp = (struct hsr_sup_payload *) skb->data;
227
228 /* Merge node_curr (registered on MacAddressB) into node_real */
229 node_db = &port_rcv->hsr->node_db;
230 node_real = find_node_by_AddrA(node_db, hsr_sp->MacAddressA);
231 if (!node_real)
232 /* No frame received from AddrA of this node yet */
233 node_real = hsr_add_node(node_db, hsr_sp->MacAddressA,
234 HSR_SEQNR_START - 1);
235 if (!node_real)
236 goto done; /* No mem */
237 if (node_real == node_curr)
238 /* Node has already been merged */
239 goto done;
240
241 ether_addr_copy(node_real->MacAddressB, ethhdr->h_source);
242 for (i = 0; i < HSR_PT_PORTS; i++) {
243 if (!node_curr->time_in_stale[i] &&
244 time_after(node_curr->time_in[i], node_real->time_in[i])) {
245 node_real->time_in[i] = node_curr->time_in[i];
246 node_real->time_in_stale[i] = node_curr->time_in_stale[i];
247 }
248 if (seq_nr_after(node_curr->seq_out[i], node_real->seq_out[i]))
249 node_real->seq_out[i] = node_curr->seq_out[i];
250 }
251 node_real->AddrB_port = port_rcv->type;
252
253 list_del_rcu(&node_curr->mac_list);
254 kfree_rcu(node_curr, rcu_head);
255
256done:
257 skb_push(skb, sizeof(struct hsrv1_ethhdr_sp));
258}
259
260
261/* 'skb' is a frame meant for this host, that is to be passed to upper layers.
262 *
263 * If the frame was sent by a node's B interface, replace the source
264 * address with that node's "official" address (MacAddressA) so that upper
265 * layers recognize where it came from.
266 */
267void hsr_addr_subst_source(struct hsr_node *node, struct sk_buff *skb)
268{
269 if (!skb_mac_header_was_set(skb)) {
270 WARN_ONCE(1, "%s: Mac header not set\n", __func__);
271 return;
272 }
273
274 memcpy(ð_hdr(skb)->h_source, node->MacAddressA, ETH_ALEN);
275}
276
277/* 'skb' is a frame meant for another host.
278 * 'port' is the outgoing interface
279 *
280 * Substitute the target (dest) MAC address if necessary, so the it matches the
281 * recipient interface MAC address, regardless of whether that is the
282 * recipient's A or B interface.
283 * This is needed to keep the packets flowing through switches that learn on
284 * which "side" the different interfaces are.
285 */
286void hsr_addr_subst_dest(struct hsr_node *node_src, struct sk_buff *skb,
287 struct hsr_port *port)
288{
289 struct hsr_node *node_dst;
290
291 if (!skb_mac_header_was_set(skb)) {
292 WARN_ONCE(1, "%s: Mac header not set\n", __func__);
293 return;
294 }
295
296 if (!is_unicast_ether_addr(eth_hdr(skb)->h_dest))
297 return;
298
299 node_dst = find_node_by_AddrA(&port->hsr->node_db, eth_hdr(skb)->h_dest);
300 if (!node_dst) {
301 WARN_ONCE(1, "%s: Unknown node\n", __func__);
302 return;
303 }
304 if (port->type != node_dst->AddrB_port)
305 return;
306
307 ether_addr_copy(eth_hdr(skb)->h_dest, node_dst->MacAddressB);
308}
309
310
311void hsr_register_frame_in(struct hsr_node *node, struct hsr_port *port,
312 u16 sequence_nr)
313{
314 /* Don't register incoming frames without a valid sequence number. This
315 * ensures entries of restarted nodes gets pruned so that they can
316 * re-register and resume communications.
317 */
318 if (seq_nr_before(sequence_nr, node->seq_out[port->type]))
319 return;
320
321 node->time_in[port->type] = jiffies;
322 node->time_in_stale[port->type] = false;
323}
324
325/* 'skb' is a HSR Ethernet frame (with a HSR tag inserted), with a valid
326 * ethhdr->h_source address and skb->mac_header set.
327 *
328 * Return:
329 * 1 if frame can be shown to have been sent recently on this interface,
330 * 0 otherwise, or
331 * negative error code on error
332 */
333int hsr_register_frame_out(struct hsr_port *port, struct hsr_node *node,
334 u16 sequence_nr)
335{
336 if (seq_nr_before_or_eq(sequence_nr, node->seq_out[port->type]))
337 return 1;
338
339 node->seq_out[port->type] = sequence_nr;
340 return 0;
341}
342
343
344static struct hsr_port *get_late_port(struct hsr_priv *hsr,
345 struct hsr_node *node)
346{
347 if (node->time_in_stale[HSR_PT_SLAVE_A])
348 return hsr_port_get_hsr(hsr, HSR_PT_SLAVE_A);
349 if (node->time_in_stale[HSR_PT_SLAVE_B])
350 return hsr_port_get_hsr(hsr, HSR_PT_SLAVE_B);
351
352 if (time_after(node->time_in[HSR_PT_SLAVE_B],
353 node->time_in[HSR_PT_SLAVE_A] +
354 msecs_to_jiffies(MAX_SLAVE_DIFF)))
355 return hsr_port_get_hsr(hsr, HSR_PT_SLAVE_A);
356 if (time_after(node->time_in[HSR_PT_SLAVE_A],
357 node->time_in[HSR_PT_SLAVE_B] +
358 msecs_to_jiffies(MAX_SLAVE_DIFF)))
359 return hsr_port_get_hsr(hsr, HSR_PT_SLAVE_B);
360
361 return NULL;
362}
363
364
365/* Remove stale sequence_nr records. Called by timer every
366 * HSR_LIFE_CHECK_INTERVAL (two seconds or so).
367 */
368void hsr_prune_nodes(struct timer_list *t)
369{
370 struct hsr_priv *hsr = from_timer(hsr, t, prune_timer);
371 struct hsr_node *node;
372 struct hsr_port *port;
373 unsigned long timestamp;
374 unsigned long time_a, time_b;
375
376 rcu_read_lock();
377 list_for_each_entry_rcu(node, &hsr->node_db, mac_list) {
378 /* Shorthand */
379 time_a = node->time_in[HSR_PT_SLAVE_A];
380 time_b = node->time_in[HSR_PT_SLAVE_B];
381
382 /* Check for timestamps old enough to risk wrap-around */
383 if (time_after(jiffies, time_a + MAX_JIFFY_OFFSET/2))
384 node->time_in_stale[HSR_PT_SLAVE_A] = true;
385 if (time_after(jiffies, time_b + MAX_JIFFY_OFFSET/2))
386 node->time_in_stale[HSR_PT_SLAVE_B] = true;
387
388 /* Get age of newest frame from node.
389 * At least one time_in is OK here; nodes get pruned long
390 * before both time_ins can get stale
391 */
392 timestamp = time_a;
393 if (node->time_in_stale[HSR_PT_SLAVE_A] ||
394 (!node->time_in_stale[HSR_PT_SLAVE_B] &&
395 time_after(time_b, time_a)))
396 timestamp = time_b;
397
398 /* Warn of ring error only as long as we get frames at all */
399 if (time_is_after_jiffies(timestamp +
400 msecs_to_jiffies(1.5*MAX_SLAVE_DIFF))) {
401 rcu_read_lock();
402 port = get_late_port(hsr, node);
403 if (port != NULL)
404 hsr_nl_ringerror(hsr, node->MacAddressA, port);
405 rcu_read_unlock();
406 }
407
408 /* Prune old entries */
409 if (time_is_before_jiffies(timestamp +
410 msecs_to_jiffies(HSR_NODE_FORGET_TIME))) {
411 hsr_nl_nodedown(hsr, node->MacAddressA);
412 list_del_rcu(&node->mac_list);
413 /* Note that we need to free this entry later: */
414 kfree_rcu(node, rcu_head);
415 }
416 }
417 rcu_read_unlock();
418}
419
420
421void *hsr_get_next_node(struct hsr_priv *hsr, void *_pos,
422 unsigned char addr[ETH_ALEN])
423{
424 struct hsr_node *node;
425
426 if (!_pos) {
427 node = list_first_or_null_rcu(&hsr->node_db,
428 struct hsr_node, mac_list);
429 if (node)
430 ether_addr_copy(addr, node->MacAddressA);
431 return node;
432 }
433
434 node = _pos;
435 list_for_each_entry_continue_rcu(node, &hsr->node_db, mac_list) {
436 ether_addr_copy(addr, node->MacAddressA);
437 return node;
438 }
439
440 return NULL;
441}
442
443
444int hsr_get_node_data(struct hsr_priv *hsr,
445 const unsigned char *addr,
446 unsigned char addr_b[ETH_ALEN],
447 unsigned int *addr_b_ifindex,
448 int *if1_age,
449 u16 *if1_seq,
450 int *if2_age,
451 u16 *if2_seq)
452{
453 struct hsr_node *node;
454 struct hsr_port *port;
455 unsigned long tdiff;
456
457
458 rcu_read_lock();
459 node = find_node_by_AddrA(&hsr->node_db, addr);
460 if (!node) {
461 rcu_read_unlock();
462 return -ENOENT; /* No such entry */
463 }
464
465 ether_addr_copy(addr_b, node->MacAddressB);
466
467 tdiff = jiffies - node->time_in[HSR_PT_SLAVE_A];
468 if (node->time_in_stale[HSR_PT_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_PT_SLAVE_B];
478 if (node->time_in_stale[HSR_PT_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_PT_SLAVE_B];
489 *if2_seq = node->seq_out[HSR_PT_SLAVE_A];
490
491 if (node->AddrB_port != HSR_PT_NONE) {
492 port = hsr_port_get_hsr(hsr, node->AddrB_port);
493 *addr_b_ifindex = port->dev->ifindex;
494 } else {
495 *addr_b_ifindex = -1;
496 }
497
498 rcu_read_unlock();
499
500 return 0;
501}