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 * Frame router for HSR and PRP.
8 */
9
10 #include "hsr_forward.h"
11 #include <linux/types.h>
12 #include <linux/skbuff.h>
13 #include <linux/etherdevice.h>
14 #include <linux/if_vlan.h>
15 #include "hsr_main.h"
16 #include "hsr_framereg.h"
17
18 struct hsr_node;
19
20 /* The uses I can see for these HSR supervision frames are:
21 * 1) Use the frames that are sent after node initialization ("HSR_TLV.Type =
22 * 22") to reset any sequence_nr counters belonging to that node. Useful if
23 * the other node's counter has been reset for some reason.
24 * --
25 * Or not - resetting the counter and bridging the frame would create a
26 * loop, unfortunately.
27 *
28 * 2) Use the LifeCheck frames to detect ring breaks. I.e. if no LifeCheck
29 * frame is received from a particular node, we know something is wrong.
30 * We just register these (as with normal frames) and throw them away.
31 *
32 * 3) Allow different MAC addresses for the two slave interfaces, using the
33 * MacAddressA field.
34 */
is_supervision_frame(struct hsr_priv * hsr,struct sk_buff * skb)35 static bool is_supervision_frame(struct hsr_priv *hsr, struct sk_buff *skb)
36 {
37 struct ethhdr *eth_hdr;
38 struct hsr_sup_tag *hsr_sup_tag;
39 struct hsrv1_ethhdr_sp *hsr_V1_hdr;
40
41 WARN_ON_ONCE(!skb_mac_header_was_set(skb));
42 eth_hdr = (struct ethhdr *)skb_mac_header(skb);
43
44 /* Correct addr? */
45 if (!ether_addr_equal(eth_hdr->h_dest,
46 hsr->sup_multicast_addr))
47 return false;
48
49 /* Correct ether type?. */
50 if (!(eth_hdr->h_proto == htons(ETH_P_PRP) ||
51 eth_hdr->h_proto == htons(ETH_P_HSR)))
52 return false;
53
54 /* Get the supervision header from correct location. */
55 if (eth_hdr->h_proto == htons(ETH_P_HSR)) { /* Okay HSRv1. */
56 hsr_V1_hdr = (struct hsrv1_ethhdr_sp *)skb_mac_header(skb);
57 if (hsr_V1_hdr->hsr.encap_proto != htons(ETH_P_PRP))
58 return false;
59
60 hsr_sup_tag = &hsr_V1_hdr->hsr_sup;
61 } else {
62 hsr_sup_tag =
63 &((struct hsrv0_ethhdr_sp *)skb_mac_header(skb))->hsr_sup;
64 }
65
66 if (hsr_sup_tag->HSR_TLV_type != HSR_TLV_ANNOUNCE &&
67 hsr_sup_tag->HSR_TLV_type != HSR_TLV_LIFE_CHECK &&
68 hsr_sup_tag->HSR_TLV_type != PRP_TLV_LIFE_CHECK_DD &&
69 hsr_sup_tag->HSR_TLV_type != PRP_TLV_LIFE_CHECK_DA)
70 return false;
71 if (hsr_sup_tag->HSR_TLV_length != 12 &&
72 hsr_sup_tag->HSR_TLV_length != sizeof(struct hsr_sup_payload))
73 return false;
74
75 return true;
76 }
77
create_stripped_skb_hsr(struct sk_buff * skb_in,struct hsr_frame_info * frame)78 static struct sk_buff *create_stripped_skb_hsr(struct sk_buff *skb_in,
79 struct hsr_frame_info *frame)
80 {
81 struct sk_buff *skb;
82 int copylen;
83 unsigned char *dst, *src;
84
85 skb_pull(skb_in, HSR_HLEN);
86 skb = __pskb_copy(skb_in, skb_headroom(skb_in) - HSR_HLEN, GFP_ATOMIC);
87 skb_push(skb_in, HSR_HLEN);
88 if (!skb)
89 return NULL;
90
91 skb_reset_mac_header(skb);
92
93 if (skb->ip_summed == CHECKSUM_PARTIAL)
94 skb->csum_start -= HSR_HLEN;
95
96 copylen = 2 * ETH_ALEN;
97 if (frame->is_vlan)
98 copylen += VLAN_HLEN;
99 src = skb_mac_header(skb_in);
100 dst = skb_mac_header(skb);
101 memcpy(dst, src, copylen);
102
103 skb->protocol = eth_hdr(skb)->h_proto;
104 return skb;
105 }
106
hsr_get_untagged_frame(struct hsr_frame_info * frame,struct hsr_port * port)107 struct sk_buff *hsr_get_untagged_frame(struct hsr_frame_info *frame,
108 struct hsr_port *port)
109 {
110 if (!frame->skb_std) {
111 if (frame->skb_hsr)
112 frame->skb_std =
113 create_stripped_skb_hsr(frame->skb_hsr, frame);
114 else
115 netdev_warn_once(port->dev,
116 "Unexpected frame received in hsr_get_untagged_frame()\n");
117
118 if (!frame->skb_std)
119 return NULL;
120 }
121
122 return skb_clone(frame->skb_std, GFP_ATOMIC);
123 }
124
prp_get_untagged_frame(struct hsr_frame_info * frame,struct hsr_port * port)125 struct sk_buff *prp_get_untagged_frame(struct hsr_frame_info *frame,
126 struct hsr_port *port)
127 {
128 if (!frame->skb_std) {
129 if (frame->skb_prp) {
130 /* trim the skb by len - HSR_HLEN to exclude RCT */
131 skb_trim(frame->skb_prp,
132 frame->skb_prp->len - HSR_HLEN);
133 frame->skb_std =
134 __pskb_copy(frame->skb_prp,
135 skb_headroom(frame->skb_prp),
136 GFP_ATOMIC);
137 } else {
138 /* Unexpected */
139 WARN_ONCE(1, "%s:%d: Unexpected frame received (port_src %s)\n",
140 __FILE__, __LINE__, port->dev->name);
141 return NULL;
142 }
143 }
144
145 return skb_clone(frame->skb_std, GFP_ATOMIC);
146 }
147
prp_set_lan_id(struct prp_rct * trailer,struct hsr_port * port)148 static void prp_set_lan_id(struct prp_rct *trailer,
149 struct hsr_port *port)
150 {
151 int lane_id;
152
153 if (port->type == HSR_PT_SLAVE_A)
154 lane_id = 0;
155 else
156 lane_id = 1;
157
158 /* Add net_id in the upper 3 bits of lane_id */
159 lane_id |= port->hsr->net_id;
160 set_prp_lan_id(trailer, lane_id);
161 }
162
163 /* Tailroom for PRP rct should have been created before calling this */
prp_fill_rct(struct sk_buff * skb,struct hsr_frame_info * frame,struct hsr_port * port)164 static struct sk_buff *prp_fill_rct(struct sk_buff *skb,
165 struct hsr_frame_info *frame,
166 struct hsr_port *port)
167 {
168 struct prp_rct *trailer;
169 int min_size = ETH_ZLEN;
170 int lsdu_size;
171
172 if (!skb)
173 return skb;
174
175 if (frame->is_vlan)
176 min_size = VLAN_ETH_ZLEN;
177
178 if (skb_put_padto(skb, min_size))
179 return NULL;
180
181 trailer = (struct prp_rct *)skb_put(skb, HSR_HLEN);
182 lsdu_size = skb->len - 14;
183 if (frame->is_vlan)
184 lsdu_size -= 4;
185 prp_set_lan_id(trailer, port);
186 set_prp_LSDU_size(trailer, lsdu_size);
187 trailer->sequence_nr = htons(frame->sequence_nr);
188 trailer->PRP_suffix = htons(ETH_P_PRP);
189 skb->protocol = eth_hdr(skb)->h_proto;
190
191 return skb;
192 }
193
hsr_set_path_id(struct hsr_ethhdr * hsr_ethhdr,struct hsr_port * port)194 static void hsr_set_path_id(struct hsr_ethhdr *hsr_ethhdr,
195 struct hsr_port *port)
196 {
197 int path_id;
198
199 if (port->type == HSR_PT_SLAVE_A)
200 path_id = 0;
201 else
202 path_id = 1;
203
204 set_hsr_tag_path(&hsr_ethhdr->hsr_tag, path_id);
205 }
206
hsr_fill_tag(struct sk_buff * skb,struct hsr_frame_info * frame,struct hsr_port * port,u8 proto_version)207 static struct sk_buff *hsr_fill_tag(struct sk_buff *skb,
208 struct hsr_frame_info *frame,
209 struct hsr_port *port, u8 proto_version)
210 {
211 struct hsr_ethhdr *hsr_ethhdr;
212 int lsdu_size;
213
214 /* pad to minimum packet size which is 60 + 6 (HSR tag) */
215 if (skb_put_padto(skb, ETH_ZLEN + HSR_HLEN))
216 return NULL;
217
218 lsdu_size = skb->len - 14;
219 if (frame->is_vlan)
220 lsdu_size -= 4;
221
222 hsr_ethhdr = (struct hsr_ethhdr *)skb_mac_header(skb);
223
224 hsr_set_path_id(hsr_ethhdr, port);
225 set_hsr_tag_LSDU_size(&hsr_ethhdr->hsr_tag, lsdu_size);
226 hsr_ethhdr->hsr_tag.sequence_nr = htons(frame->sequence_nr);
227 hsr_ethhdr->hsr_tag.encap_proto = hsr_ethhdr->ethhdr.h_proto;
228 hsr_ethhdr->ethhdr.h_proto = htons(proto_version ?
229 ETH_P_HSR : ETH_P_PRP);
230 skb->protocol = hsr_ethhdr->ethhdr.h_proto;
231
232 return skb;
233 }
234
235 /* If the original frame was an HSR tagged frame, just clone it to be sent
236 * unchanged. Otherwise, create a private frame especially tagged for 'port'.
237 */
hsr_create_tagged_frame(struct hsr_frame_info * frame,struct hsr_port * port)238 struct sk_buff *hsr_create_tagged_frame(struct hsr_frame_info *frame,
239 struct hsr_port *port)
240 {
241 unsigned char *dst, *src;
242 struct sk_buff *skb;
243 int movelen;
244
245 if (frame->skb_hsr) {
246 struct hsr_ethhdr *hsr_ethhdr =
247 (struct hsr_ethhdr *)skb_mac_header(frame->skb_hsr);
248
249 /* set the lane id properly */
250 hsr_set_path_id(hsr_ethhdr, port);
251 return skb_clone(frame->skb_hsr, GFP_ATOMIC);
252 }
253
254 /* Create the new skb with enough headroom to fit the HSR tag */
255 skb = __pskb_copy(frame->skb_std,
256 skb_headroom(frame->skb_std) + HSR_HLEN, GFP_ATOMIC);
257 if (!skb)
258 return NULL;
259 skb_reset_mac_header(skb);
260
261 if (skb->ip_summed == CHECKSUM_PARTIAL)
262 skb->csum_start += HSR_HLEN;
263
264 movelen = ETH_HLEN;
265 if (frame->is_vlan)
266 movelen += VLAN_HLEN;
267
268 src = skb_mac_header(skb);
269 dst = skb_push(skb, HSR_HLEN);
270 memmove(dst, src, movelen);
271 skb_reset_mac_header(skb);
272
273 /* skb_put_padto free skb on error and hsr_fill_tag returns NULL in
274 * that case
275 */
276 return hsr_fill_tag(skb, frame, port, port->hsr->prot_version);
277 }
278
prp_create_tagged_frame(struct hsr_frame_info * frame,struct hsr_port * port)279 struct sk_buff *prp_create_tagged_frame(struct hsr_frame_info *frame,
280 struct hsr_port *port)
281 {
282 struct sk_buff *skb;
283
284 if (frame->skb_prp) {
285 struct prp_rct *trailer = skb_get_PRP_rct(frame->skb_prp);
286
287 if (trailer) {
288 prp_set_lan_id(trailer, port);
289 } else {
290 WARN_ONCE(!trailer, "errored PRP skb");
291 return NULL;
292 }
293 return skb_clone(frame->skb_prp, GFP_ATOMIC);
294 }
295
296 skb = skb_copy_expand(frame->skb_std, 0,
297 skb_tailroom(frame->skb_std) + HSR_HLEN,
298 GFP_ATOMIC);
299 return prp_fill_rct(skb, frame, port);
300 }
301
hsr_deliver_master(struct sk_buff * skb,struct net_device * dev,struct hsr_node * node_src)302 static void hsr_deliver_master(struct sk_buff *skb, struct net_device *dev,
303 struct hsr_node *node_src)
304 {
305 bool was_multicast_frame;
306 int res, recv_len;
307
308 was_multicast_frame = (skb->pkt_type == PACKET_MULTICAST);
309 hsr_addr_subst_source(node_src, skb);
310 skb_pull(skb, ETH_HLEN);
311 recv_len = skb->len;
312 res = netif_rx(skb);
313 if (res == NET_RX_DROP) {
314 dev->stats.rx_dropped++;
315 } else {
316 dev->stats.rx_packets++;
317 dev->stats.rx_bytes += recv_len;
318 if (was_multicast_frame)
319 dev->stats.multicast++;
320 }
321 }
322
hsr_xmit(struct sk_buff * skb,struct hsr_port * port,struct hsr_frame_info * frame)323 static int hsr_xmit(struct sk_buff *skb, struct hsr_port *port,
324 struct hsr_frame_info *frame)
325 {
326 if (frame->port_rcv->type == HSR_PT_MASTER) {
327 hsr_addr_subst_dest(frame->node_src, skb, port);
328
329 /* Address substitution (IEC62439-3 pp 26, 50): replace mac
330 * address of outgoing frame with that of the outgoing slave's.
331 */
332 ether_addr_copy(eth_hdr(skb)->h_source, port->dev->dev_addr);
333 }
334 return dev_queue_xmit(skb);
335 }
336
prp_drop_frame(struct hsr_frame_info * frame,struct hsr_port * port)337 bool prp_drop_frame(struct hsr_frame_info *frame, struct hsr_port *port)
338 {
339 return ((frame->port_rcv->type == HSR_PT_SLAVE_A &&
340 port->type == HSR_PT_SLAVE_B) ||
341 (frame->port_rcv->type == HSR_PT_SLAVE_B &&
342 port->type == HSR_PT_SLAVE_A));
343 }
344
345 /* Forward the frame through all devices except:
346 * - Back through the receiving device
347 * - If it's a HSR frame: through a device where it has passed before
348 * - if it's a PRP frame: through another PRP slave device (no bridge)
349 * - To the local HSR master only if the frame is directly addressed to it, or
350 * a non-supervision multicast or broadcast frame.
351 *
352 * HSR slave devices should insert a HSR tag into the frame, or forward the
353 * frame unchanged if it's already tagged. Interlink devices should strip HSR
354 * tags if they're of the non-HSR type (but only after duplicate discard). The
355 * master device always strips HSR tags.
356 */
hsr_forward_do(struct hsr_frame_info * frame)357 static void hsr_forward_do(struct hsr_frame_info *frame)
358 {
359 struct hsr_port *port;
360 struct sk_buff *skb;
361
362 hsr_for_each_port(frame->port_rcv->hsr, port) {
363 struct hsr_priv *hsr = port->hsr;
364 /* Don't send frame back the way it came */
365 if (port == frame->port_rcv)
366 continue;
367
368 /* Don't deliver locally unless we should */
369 if (port->type == HSR_PT_MASTER && !frame->is_local_dest)
370 continue;
371
372 /* Deliver frames directly addressed to us to master only */
373 if (port->type != HSR_PT_MASTER && frame->is_local_exclusive)
374 continue;
375
376 /* Don't send frame over port where it has been sent before.
377 * Also fro SAN, this shouldn't be done.
378 */
379 if (!frame->is_from_san &&
380 hsr_register_frame_out(port, frame->node_src,
381 frame->sequence_nr))
382 continue;
383
384 if (frame->is_supervision && port->type == HSR_PT_MASTER) {
385 hsr_handle_sup_frame(frame);
386 continue;
387 }
388
389 /* Check if frame is to be dropped. Eg. for PRP no forward
390 * between ports.
391 */
392 if (hsr->proto_ops->drop_frame &&
393 hsr->proto_ops->drop_frame(frame, port))
394 continue;
395
396 if (port->type != HSR_PT_MASTER)
397 skb = hsr->proto_ops->create_tagged_frame(frame, port);
398 else
399 skb = hsr->proto_ops->get_untagged_frame(frame, port);
400
401 if (!skb) {
402 frame->port_rcv->dev->stats.rx_dropped++;
403 continue;
404 }
405
406 skb->dev = port->dev;
407 if (port->type == HSR_PT_MASTER)
408 hsr_deliver_master(skb, port->dev, frame->node_src);
409 else
410 hsr_xmit(skb, port, frame);
411 }
412 }
413
check_local_dest(struct hsr_priv * hsr,struct sk_buff * skb,struct hsr_frame_info * frame)414 static void check_local_dest(struct hsr_priv *hsr, struct sk_buff *skb,
415 struct hsr_frame_info *frame)
416 {
417 if (hsr_addr_is_self(hsr, eth_hdr(skb)->h_dest)) {
418 frame->is_local_exclusive = true;
419 skb->pkt_type = PACKET_HOST;
420 } else {
421 frame->is_local_exclusive = false;
422 }
423
424 if (skb->pkt_type == PACKET_HOST ||
425 skb->pkt_type == PACKET_MULTICAST ||
426 skb->pkt_type == PACKET_BROADCAST) {
427 frame->is_local_dest = true;
428 } else {
429 frame->is_local_dest = false;
430 }
431 }
432
handle_std_frame(struct sk_buff * skb,struct hsr_frame_info * frame)433 static void handle_std_frame(struct sk_buff *skb,
434 struct hsr_frame_info *frame)
435 {
436 struct hsr_port *port = frame->port_rcv;
437 struct hsr_priv *hsr = port->hsr;
438
439 frame->skb_hsr = NULL;
440 frame->skb_prp = NULL;
441 frame->skb_std = skb;
442
443 if (port->type != HSR_PT_MASTER) {
444 frame->is_from_san = true;
445 } else {
446 /* Sequence nr for the master node */
447 lockdep_assert_held(&hsr->seqnr_lock);
448 frame->sequence_nr = hsr->sequence_nr;
449 hsr->sequence_nr++;
450 }
451 }
452
hsr_fill_frame_info(__be16 proto,struct sk_buff * skb,struct hsr_frame_info * frame)453 int hsr_fill_frame_info(__be16 proto, struct sk_buff *skb,
454 struct hsr_frame_info *frame)
455 {
456 struct hsr_port *port = frame->port_rcv;
457 struct hsr_priv *hsr = port->hsr;
458
459 /* HSRv0 supervisory frames double as a tag so treat them as tagged. */
460 if ((!hsr->prot_version && proto == htons(ETH_P_PRP)) ||
461 proto == htons(ETH_P_HSR)) {
462 /* Check if skb contains hsr_ethhdr */
463 if (skb->mac_len < sizeof(struct hsr_ethhdr))
464 return -EINVAL;
465
466 /* HSR tagged frame :- Data or Supervision */
467 frame->skb_std = NULL;
468 frame->skb_prp = NULL;
469 frame->skb_hsr = skb;
470 frame->sequence_nr = hsr_get_skb_sequence_nr(skb);
471 return 0;
472 }
473
474 /* Standard frame or PRP from master port */
475 handle_std_frame(skb, frame);
476
477 return 0;
478 }
479
prp_fill_frame_info(__be16 proto,struct sk_buff * skb,struct hsr_frame_info * frame)480 int prp_fill_frame_info(__be16 proto, struct sk_buff *skb,
481 struct hsr_frame_info *frame)
482 {
483 /* Supervision frame */
484 struct prp_rct *rct = skb_get_PRP_rct(skb);
485
486 if (rct &&
487 prp_check_lsdu_size(skb, rct, frame->is_supervision)) {
488 frame->skb_hsr = NULL;
489 frame->skb_std = NULL;
490 frame->skb_prp = skb;
491 frame->sequence_nr = prp_get_skb_sequence_nr(rct);
492 return 0;
493 }
494 handle_std_frame(skb, frame);
495
496 return 0;
497 }
498
fill_frame_info(struct hsr_frame_info * frame,struct sk_buff * skb,struct hsr_port * port)499 static int fill_frame_info(struct hsr_frame_info *frame,
500 struct sk_buff *skb, struct hsr_port *port)
501 {
502 struct hsr_priv *hsr = port->hsr;
503 struct hsr_vlan_ethhdr *vlan_hdr;
504 struct ethhdr *ethhdr;
505 __be16 proto;
506 int ret;
507
508 /* Check if skb contains ethhdr */
509 if (skb->mac_len < sizeof(struct ethhdr))
510 return -EINVAL;
511
512 memset(frame, 0, sizeof(*frame));
513 frame->is_supervision = is_supervision_frame(port->hsr, skb);
514 frame->node_src = hsr_get_node(port, &hsr->node_db, skb,
515 frame->is_supervision,
516 port->type);
517 if (!frame->node_src)
518 return -1; /* Unknown node and !is_supervision, or no mem */
519
520 ethhdr = (struct ethhdr *)skb_mac_header(skb);
521 frame->is_vlan = false;
522 proto = ethhdr->h_proto;
523
524 if (proto == htons(ETH_P_8021Q))
525 frame->is_vlan = true;
526
527 if (frame->is_vlan) {
528 vlan_hdr = (struct hsr_vlan_ethhdr *)ethhdr;
529 proto = vlan_hdr->vlanhdr.h_vlan_encapsulated_proto;
530 /* FIXME: */
531 netdev_warn_once(skb->dev, "VLAN not yet supported");
532 return -EINVAL;
533 }
534
535 frame->is_from_san = false;
536 frame->port_rcv = port;
537 ret = hsr->proto_ops->fill_frame_info(proto, skb, frame);
538 if (ret)
539 return ret;
540
541 check_local_dest(port->hsr, skb, frame);
542
543 return 0;
544 }
545
546 /* Must be called holding rcu read lock (because of the port parameter) */
hsr_forward_skb(struct sk_buff * skb,struct hsr_port * port)547 void hsr_forward_skb(struct sk_buff *skb, struct hsr_port *port)
548 {
549 struct hsr_frame_info frame;
550
551 rcu_read_lock();
552 if (fill_frame_info(&frame, skb, port) < 0)
553 goto out_drop;
554
555 hsr_register_frame_in(frame.node_src, port, frame.sequence_nr);
556 hsr_forward_do(&frame);
557 rcu_read_unlock();
558 /* Gets called for ingress frames as well as egress from master port.
559 * So check and increment stats for master port only here.
560 */
561 if (port->type == HSR_PT_MASTER) {
562 port->dev->stats.tx_packets++;
563 port->dev->stats.tx_bytes += skb->len;
564 }
565
566 kfree_skb(frame.skb_hsr);
567 kfree_skb(frame.skb_prp);
568 kfree_skb(frame.skb_std);
569 return;
570
571 out_drop:
572 rcu_read_unlock();
573 port->dev->stats.tx_dropped++;
574 kfree_skb(skb);
575 }
576