1// SPDX-License-Identifier: GPL-2.0
2/* Copyright (c) 2019, Vladimir Oltean <olteanv@gmail.com>
3 *
4 * This module is not a complete tagger implementation. It only provides
5 * primitives for taggers that rely on 802.1Q VLAN tags to use.
6 */
7#include <linux/if_vlan.h>
8#include <linux/dsa/8021q.h>
9
10#include "port.h"
11#include "switch.h"
12#include "tag.h"
13#include "tag_8021q.h"
14
15/* Binary structure of the fake 12-bit VID field (when the TPID is
16 * ETH_P_DSA_8021Q):
17 *
18 * | 11 | 10 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
19 * +-----------+-----+-----------------+-----------+-----------------------+
20 * | RSV | VBID| SWITCH_ID | VBID | PORT |
21 * +-----------+-----+-----------------+-----------+-----------------------+
22 *
23 * RSV - VID[11:10]:
24 * Reserved. Must be set to 3 (0b11).
25 *
26 * SWITCH_ID - VID[8:6]:
27 * Index of switch within DSA tree. Must be between 0 and 7.
28 *
29 * VBID - { VID[9], VID[5:4] }:
30 * Virtual bridge ID. If between 1 and 7, packet targets the broadcast
31 * domain of a bridge. If transmitted as zero, packet targets a single
32 * port.
33 *
34 * PORT - VID[3:0]:
35 * Index of switch port. Must be between 0 and 15.
36 */
37
38#define DSA_8021Q_RSV_VAL 3
39#define DSA_8021Q_RSV_SHIFT 10
40#define DSA_8021Q_RSV_MASK GENMASK(11, 10)
41#define DSA_8021Q_RSV ((DSA_8021Q_RSV_VAL << DSA_8021Q_RSV_SHIFT) & \
42 DSA_8021Q_RSV_MASK)
43
44#define DSA_8021Q_SWITCH_ID_SHIFT 6
45#define DSA_8021Q_SWITCH_ID_MASK GENMASK(8, 6)
46#define DSA_8021Q_SWITCH_ID(x) (((x) << DSA_8021Q_SWITCH_ID_SHIFT) & \
47 DSA_8021Q_SWITCH_ID_MASK)
48
49#define DSA_8021Q_VBID_HI_SHIFT 9
50#define DSA_8021Q_VBID_HI_MASK GENMASK(9, 9)
51#define DSA_8021Q_VBID_LO_SHIFT 4
52#define DSA_8021Q_VBID_LO_MASK GENMASK(5, 4)
53#define DSA_8021Q_VBID_HI(x) (((x) & GENMASK(2, 2)) >> 2)
54#define DSA_8021Q_VBID_LO(x) ((x) & GENMASK(1, 0))
55#define DSA_8021Q_VBID(x) \
56 (((DSA_8021Q_VBID_LO(x) << DSA_8021Q_VBID_LO_SHIFT) & \
57 DSA_8021Q_VBID_LO_MASK) | \
58 ((DSA_8021Q_VBID_HI(x) << DSA_8021Q_VBID_HI_SHIFT) & \
59 DSA_8021Q_VBID_HI_MASK))
60
61#define DSA_8021Q_PORT_SHIFT 0
62#define DSA_8021Q_PORT_MASK GENMASK(3, 0)
63#define DSA_8021Q_PORT(x) (((x) << DSA_8021Q_PORT_SHIFT) & \
64 DSA_8021Q_PORT_MASK)
65
66struct dsa_tag_8021q_vlan {
67 struct list_head list;
68 int port;
69 u16 vid;
70 refcount_t refcount;
71};
72
73struct dsa_8021q_context {
74 struct dsa_switch *ds;
75 struct list_head vlans;
76 /* EtherType of RX VID, used for filtering on conduit interface */
77 __be16 proto;
78};
79
80u16 dsa_tag_8021q_bridge_vid(unsigned int bridge_num)
81{
82 /* The VBID value of 0 is reserved for precise TX, but it is also
83 * reserved/invalid for the bridge_num, so all is well.
84 */
85 return DSA_8021Q_RSV | DSA_8021Q_VBID(bridge_num);
86}
87EXPORT_SYMBOL_GPL(dsa_tag_8021q_bridge_vid);
88
89/* Returns the VID that will be installed as pvid for this switch port, sent as
90 * tagged egress towards the CPU port and decoded by the rcv function.
91 */
92u16 dsa_tag_8021q_standalone_vid(const struct dsa_port *dp)
93{
94 return DSA_8021Q_RSV | DSA_8021Q_SWITCH_ID(dp->ds->index) |
95 DSA_8021Q_PORT(dp->index);
96}
97EXPORT_SYMBOL_GPL(dsa_tag_8021q_standalone_vid);
98
99/* Returns the decoded switch ID from the RX VID. */
100int dsa_8021q_rx_switch_id(u16 vid)
101{
102 return (vid & DSA_8021Q_SWITCH_ID_MASK) >> DSA_8021Q_SWITCH_ID_SHIFT;
103}
104EXPORT_SYMBOL_GPL(dsa_8021q_rx_switch_id);
105
106/* Returns the decoded port ID from the RX VID. */
107int dsa_8021q_rx_source_port(u16 vid)
108{
109 return (vid & DSA_8021Q_PORT_MASK) >> DSA_8021Q_PORT_SHIFT;
110}
111EXPORT_SYMBOL_GPL(dsa_8021q_rx_source_port);
112
113/* Returns the decoded VBID from the RX VID. */
114static int dsa_tag_8021q_rx_vbid(u16 vid)
115{
116 u16 vbid_hi = (vid & DSA_8021Q_VBID_HI_MASK) >> DSA_8021Q_VBID_HI_SHIFT;
117 u16 vbid_lo = (vid & DSA_8021Q_VBID_LO_MASK) >> DSA_8021Q_VBID_LO_SHIFT;
118
119 return (vbid_hi << 2) | vbid_lo;
120}
121
122bool vid_is_dsa_8021q(u16 vid)
123{
124 u16 rsv = (vid & DSA_8021Q_RSV_MASK) >> DSA_8021Q_RSV_SHIFT;
125
126 return rsv == DSA_8021Q_RSV_VAL;
127}
128EXPORT_SYMBOL_GPL(vid_is_dsa_8021q);
129
130static struct dsa_tag_8021q_vlan *
131dsa_tag_8021q_vlan_find(struct dsa_8021q_context *ctx, int port, u16 vid)
132{
133 struct dsa_tag_8021q_vlan *v;
134
135 list_for_each_entry(v, &ctx->vlans, list)
136 if (v->vid == vid && v->port == port)
137 return v;
138
139 return NULL;
140}
141
142static int dsa_port_do_tag_8021q_vlan_add(struct dsa_port *dp, u16 vid,
143 u16 flags)
144{
145 struct dsa_8021q_context *ctx = dp->ds->tag_8021q_ctx;
146 struct dsa_switch *ds = dp->ds;
147 struct dsa_tag_8021q_vlan *v;
148 int port = dp->index;
149 int err;
150
151 /* No need to bother with refcounting for user ports */
152 if (!(dsa_port_is_cpu(port: dp) || dsa_port_is_dsa(port: dp)))
153 return ds->ops->tag_8021q_vlan_add(ds, port, vid, flags);
154
155 v = dsa_tag_8021q_vlan_find(ctx, port, vid);
156 if (v) {
157 refcount_inc(r: &v->refcount);
158 return 0;
159 }
160
161 v = kzalloc(sizeof(*v), GFP_KERNEL);
162 if (!v)
163 return -ENOMEM;
164
165 err = ds->ops->tag_8021q_vlan_add(ds, port, vid, flags);
166 if (err) {
167 kfree(objp: v);
168 return err;
169 }
170
171 v->vid = vid;
172 v->port = port;
173 refcount_set(r: &v->refcount, n: 1);
174 list_add_tail(new: &v->list, head: &ctx->vlans);
175
176 return 0;
177}
178
179static int dsa_port_do_tag_8021q_vlan_del(struct dsa_port *dp, u16 vid)
180{
181 struct dsa_8021q_context *ctx = dp->ds->tag_8021q_ctx;
182 struct dsa_switch *ds = dp->ds;
183 struct dsa_tag_8021q_vlan *v;
184 int port = dp->index;
185 int err;
186
187 /* No need to bother with refcounting for user ports */
188 if (!(dsa_port_is_cpu(port: dp) || dsa_port_is_dsa(port: dp)))
189 return ds->ops->tag_8021q_vlan_del(ds, port, vid);
190
191 v = dsa_tag_8021q_vlan_find(ctx, port, vid);
192 if (!v)
193 return -ENOENT;
194
195 if (!refcount_dec_and_test(r: &v->refcount))
196 return 0;
197
198 err = ds->ops->tag_8021q_vlan_del(ds, port, vid);
199 if (err) {
200 refcount_set(r: &v->refcount, n: 1);
201 return err;
202 }
203
204 list_del(entry: &v->list);
205 kfree(objp: v);
206
207 return 0;
208}
209
210static bool
211dsa_port_tag_8021q_vlan_match(struct dsa_port *dp,
212 struct dsa_notifier_tag_8021q_vlan_info *info)
213{
214 return dsa_port_is_dsa(port: dp) || dsa_port_is_cpu(port: dp) || dp == info->dp;
215}
216
217int dsa_switch_tag_8021q_vlan_add(struct dsa_switch *ds,
218 struct dsa_notifier_tag_8021q_vlan_info *info)
219{
220 struct dsa_port *dp;
221 int err;
222
223 /* Since we use dsa_broadcast(), there might be other switches in other
224 * trees which don't support tag_8021q, so don't return an error.
225 * Or they might even support tag_8021q but have not registered yet to
226 * use it (maybe they use another tagger currently).
227 */
228 if (!ds->ops->tag_8021q_vlan_add || !ds->tag_8021q_ctx)
229 return 0;
230
231 dsa_switch_for_each_port(dp, ds) {
232 if (dsa_port_tag_8021q_vlan_match(dp, info)) {
233 u16 flags = 0;
234
235 if (dsa_port_is_user(dp))
236 flags |= BRIDGE_VLAN_INFO_UNTAGGED |
237 BRIDGE_VLAN_INFO_PVID;
238
239 err = dsa_port_do_tag_8021q_vlan_add(dp, vid: info->vid,
240 flags);
241 if (err)
242 return err;
243 }
244 }
245
246 return 0;
247}
248
249int dsa_switch_tag_8021q_vlan_del(struct dsa_switch *ds,
250 struct dsa_notifier_tag_8021q_vlan_info *info)
251{
252 struct dsa_port *dp;
253 int err;
254
255 if (!ds->ops->tag_8021q_vlan_del || !ds->tag_8021q_ctx)
256 return 0;
257
258 dsa_switch_for_each_port(dp, ds) {
259 if (dsa_port_tag_8021q_vlan_match(dp, info)) {
260 err = dsa_port_do_tag_8021q_vlan_del(dp, vid: info->vid);
261 if (err)
262 return err;
263 }
264 }
265
266 return 0;
267}
268
269/* There are 2 ways of offloading tag_8021q VLANs.
270 *
271 * One is to use a hardware TCAM to push the port's standalone VLAN into the
272 * frame when forwarding it to the CPU, as an egress modification rule on the
273 * CPU port. This is preferable because it has no side effects for the
274 * autonomous forwarding path, and accomplishes tag_8021q's primary goal of
275 * identifying the source port of each packet based on VLAN ID.
276 *
277 * The other is to commit the tag_8021q VLAN as a PVID to the VLAN table, and
278 * to configure the port as VLAN-unaware. This is less preferable because
279 * unique source port identification can only be done for standalone ports;
280 * under a VLAN-unaware bridge, all ports share the same tag_8021q VLAN as
281 * PVID, and under a VLAN-aware bridge, packets received by software will not
282 * have tag_8021q VLANs appended, just bridge VLANs.
283 *
284 * For tag_8021q implementations of the second type, this method is used to
285 * replace the standalone tag_8021q VLAN of a port with the tag_8021q VLAN to
286 * be used for VLAN-unaware bridging.
287 */
288int dsa_tag_8021q_bridge_join(struct dsa_switch *ds, int port,
289 struct dsa_bridge bridge, bool *tx_fwd_offload,
290 struct netlink_ext_ack *extack)
291{
292 struct dsa_port *dp = dsa_to_port(ds, p: port);
293 u16 standalone_vid, bridge_vid;
294 int err;
295
296 /* Delete the standalone VLAN of the port and replace it with a
297 * bridging VLAN
298 */
299 standalone_vid = dsa_tag_8021q_standalone_vid(dp);
300 bridge_vid = dsa_tag_8021q_bridge_vid(bridge.num);
301
302 err = dsa_port_tag_8021q_vlan_add(dp, vid: bridge_vid, broadcast: true);
303 if (err)
304 return err;
305
306 dsa_port_tag_8021q_vlan_del(dp, vid: standalone_vid, broadcast: false);
307
308 *tx_fwd_offload = true;
309
310 return 0;
311}
312EXPORT_SYMBOL_GPL(dsa_tag_8021q_bridge_join);
313
314void dsa_tag_8021q_bridge_leave(struct dsa_switch *ds, int port,
315 struct dsa_bridge bridge)
316{
317 struct dsa_port *dp = dsa_to_port(ds, p: port);
318 u16 standalone_vid, bridge_vid;
319 int err;
320
321 /* Delete the bridging VLAN of the port and replace it with a
322 * standalone VLAN
323 */
324 standalone_vid = dsa_tag_8021q_standalone_vid(dp);
325 bridge_vid = dsa_tag_8021q_bridge_vid(bridge.num);
326
327 err = dsa_port_tag_8021q_vlan_add(dp, vid: standalone_vid, broadcast: false);
328 if (err) {
329 dev_err(ds->dev,
330 "Failed to delete tag_8021q standalone VLAN %d from port %d: %pe\n",
331 standalone_vid, port, ERR_PTR(err));
332 }
333
334 dsa_port_tag_8021q_vlan_del(dp, vid: bridge_vid, broadcast: true);
335}
336EXPORT_SYMBOL_GPL(dsa_tag_8021q_bridge_leave);
337
338/* Set up a port's standalone tag_8021q VLAN */
339static int dsa_tag_8021q_port_setup(struct dsa_switch *ds, int port)
340{
341 struct dsa_8021q_context *ctx = ds->tag_8021q_ctx;
342 struct dsa_port *dp = dsa_to_port(ds, p: port);
343 u16 vid = dsa_tag_8021q_standalone_vid(dp);
344 struct net_device *conduit;
345 int err;
346
347 /* The CPU port is implicitly configured by
348 * configuring the front-panel ports
349 */
350 if (!dsa_port_is_user(dp))
351 return 0;
352
353 conduit = dsa_port_to_conduit(dp);
354
355 err = dsa_port_tag_8021q_vlan_add(dp, vid, broadcast: false);
356 if (err) {
357 dev_err(ds->dev,
358 "Failed to apply standalone VID %d to port %d: %pe\n",
359 vid, port, ERR_PTR(err));
360 return err;
361 }
362
363 /* Add the VLAN to the conduit's RX filter. */
364 vlan_vid_add(dev: conduit, proto: ctx->proto, vid);
365
366 return err;
367}
368
369static void dsa_tag_8021q_port_teardown(struct dsa_switch *ds, int port)
370{
371 struct dsa_8021q_context *ctx = ds->tag_8021q_ctx;
372 struct dsa_port *dp = dsa_to_port(ds, p: port);
373 u16 vid = dsa_tag_8021q_standalone_vid(dp);
374 struct net_device *conduit;
375
376 /* The CPU port is implicitly configured by
377 * configuring the front-panel ports
378 */
379 if (!dsa_port_is_user(dp))
380 return;
381
382 conduit = dsa_port_to_conduit(dp);
383
384 dsa_port_tag_8021q_vlan_del(dp, vid, broadcast: false);
385
386 vlan_vid_del(dev: conduit, proto: ctx->proto, vid);
387}
388
389static int dsa_tag_8021q_setup(struct dsa_switch *ds)
390{
391 int err, port;
392
393 ASSERT_RTNL();
394
395 for (port = 0; port < ds->num_ports; port++) {
396 err = dsa_tag_8021q_port_setup(ds, port);
397 if (err < 0) {
398 dev_err(ds->dev,
399 "Failed to setup VLAN tagging for port %d: %pe\n",
400 port, ERR_PTR(err));
401 return err;
402 }
403 }
404
405 return 0;
406}
407
408static void dsa_tag_8021q_teardown(struct dsa_switch *ds)
409{
410 int port;
411
412 ASSERT_RTNL();
413
414 for (port = 0; port < ds->num_ports; port++)
415 dsa_tag_8021q_port_teardown(ds, port);
416}
417
418int dsa_tag_8021q_register(struct dsa_switch *ds, __be16 proto)
419{
420 struct dsa_8021q_context *ctx;
421 int err;
422
423 ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
424 if (!ctx)
425 return -ENOMEM;
426
427 ctx->proto = proto;
428 ctx->ds = ds;
429
430 INIT_LIST_HEAD(list: &ctx->vlans);
431
432 ds->tag_8021q_ctx = ctx;
433
434 err = dsa_tag_8021q_setup(ds);
435 if (err)
436 goto err_free;
437
438 return 0;
439
440err_free:
441 kfree(objp: ctx);
442 return err;
443}
444EXPORT_SYMBOL_GPL(dsa_tag_8021q_register);
445
446void dsa_tag_8021q_unregister(struct dsa_switch *ds)
447{
448 struct dsa_8021q_context *ctx = ds->tag_8021q_ctx;
449 struct dsa_tag_8021q_vlan *v, *n;
450
451 dsa_tag_8021q_teardown(ds);
452
453 list_for_each_entry_safe(v, n, &ctx->vlans, list) {
454 list_del(entry: &v->list);
455 kfree(objp: v);
456 }
457
458 ds->tag_8021q_ctx = NULL;
459
460 kfree(objp: ctx);
461}
462EXPORT_SYMBOL_GPL(dsa_tag_8021q_unregister);
463
464struct sk_buff *dsa_8021q_xmit(struct sk_buff *skb, struct net_device *netdev,
465 u16 tpid, u16 tci)
466{
467 /* skb->data points at the MAC header, which is fine
468 * for vlan_insert_tag().
469 */
470 return vlan_insert_tag(skb, htons(tpid), vlan_tci: tci);
471}
472EXPORT_SYMBOL_GPL(dsa_8021q_xmit);
473
474static struct net_device *
475dsa_tag_8021q_find_port_by_vbid(struct net_device *conduit, int vbid)
476{
477 struct dsa_port *cpu_dp = conduit->dsa_ptr;
478 struct dsa_switch_tree *dst = cpu_dp->dst;
479 struct dsa_port *dp;
480
481 if (WARN_ON(!vbid))
482 return NULL;
483
484 dsa_tree_for_each_user_port(dp, dst) {
485 if (!dp->bridge)
486 continue;
487
488 if (dp->stp_state != BR_STATE_LEARNING &&
489 dp->stp_state != BR_STATE_FORWARDING)
490 continue;
491
492 if (dp->cpu_dp != cpu_dp)
493 continue;
494
495 if (dsa_port_bridge_num_get(dp) == vbid)
496 return dp->user;
497 }
498
499 return NULL;
500}
501
502struct net_device *dsa_tag_8021q_find_user(struct net_device *conduit,
503 int source_port, int switch_id,
504 int vid, int vbid)
505{
506 /* Always prefer precise source port information, if available */
507 if (source_port != -1 && switch_id != -1)
508 return dsa_conduit_find_user(dev: conduit, device: switch_id, port: source_port);
509 else if (vbid >= 1)
510 return dsa_tag_8021q_find_port_by_vbid(conduit, vbid);
511
512 return dsa_find_designated_bridge_port_by_vid(conduit, vid);
513}
514EXPORT_SYMBOL_GPL(dsa_tag_8021q_find_user);
515
516/**
517 * dsa_8021q_rcv - Decode source information from tag_8021q header
518 * @skb: RX socket buffer
519 * @source_port: pointer to storage for precise source port information.
520 * If this is known already from outside tag_8021q, the pre-initialized
521 * value is preserved. If not known, pass -1.
522 * @switch_id: similar to source_port.
523 * @vbid: pointer to storage for imprecise bridge ID. Must be pre-initialized
524 * with -1. If a positive value is returned, the source_port and switch_id
525 * are invalid.
526 * @vid: pointer to storage for original VID, in case tag_8021q decoding failed.
527 *
528 * If the packet has a tag_8021q header, decode it and set @source_port,
529 * @switch_id and @vbid, and strip the header. Otherwise set @vid and keep the
530 * header in the hwaccel area of the packet.
531 */
532void dsa_8021q_rcv(struct sk_buff *skb, int *source_port, int *switch_id,
533 int *vbid, int *vid)
534{
535 int tmp_source_port, tmp_switch_id, tmp_vbid;
536 __be16 vlan_proto;
537 u16 tmp_vid, tci;
538
539 if (skb_vlan_tag_present(skb)) {
540 vlan_proto = skb->vlan_proto;
541 tci = skb_vlan_tag_get(skb);
542 __vlan_hwaccel_clear_tag(skb);
543 } else {
544 struct vlan_ethhdr *hdr = vlan_eth_hdr(skb);
545
546 vlan_proto = hdr->h_vlan_proto;
547 skb_push_rcsum(skb, ETH_HLEN);
548 __skb_vlan_pop(skb, vlan_tci: &tci);
549 skb_pull_rcsum(skb, ETH_HLEN);
550 }
551
552 tmp_vid = tci & VLAN_VID_MASK;
553 if (!vid_is_dsa_8021q(tmp_vid)) {
554 /* Not a tag_8021q frame, so return the VID to the
555 * caller for further processing, and put the tag back
556 */
557 if (vid)
558 *vid = tmp_vid;
559
560 __vlan_hwaccel_put_tag(skb, vlan_proto, vlan_tci: tci);
561
562 return;
563 }
564
565 tmp_source_port = dsa_8021q_rx_source_port(tmp_vid);
566 tmp_switch_id = dsa_8021q_rx_switch_id(tmp_vid);
567 tmp_vbid = dsa_tag_8021q_rx_vbid(vid: tmp_vid);
568
569 /* Precise source port information is unknown when receiving from a
570 * VLAN-unaware bridging domain, and tmp_source_port and tmp_switch_id
571 * are zeroes in this case.
572 *
573 * Preserve the source information from hardware-specific mechanisms,
574 * if available. This allows us to not overwrite a valid source port
575 * and switch ID with less precise values.
576 */
577 if (tmp_vbid == 0 && *source_port == -1)
578 *source_port = tmp_source_port;
579 if (tmp_vbid == 0 && *switch_id == -1)
580 *switch_id = tmp_switch_id;
581
582 if (vbid)
583 *vbid = tmp_vbid;
584
585 skb->priority = (tci & VLAN_PRIO_MASK) >> VLAN_PRIO_SHIFT;
586 return;
587}
588EXPORT_SYMBOL_GPL(dsa_8021q_rcv);
589

source code of linux/net/dsa/tag_8021q.c