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(size: 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_inc(r: &v->refcount);
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)
290{
291 struct dsa_port *dp = dsa_to_port(ds, p: port);
292 u16 standalone_vid, bridge_vid;
293 int err;
294
295 /* Delete the standalone VLAN of the port and replace it with a
296 * bridging VLAN
297 */
298 standalone_vid = dsa_tag_8021q_standalone_vid(dp);
299 bridge_vid = dsa_tag_8021q_bridge_vid(bridge.num);
300
301 err = dsa_port_tag_8021q_vlan_add(dp, vid: bridge_vid, broadcast: true);
302 if (err)
303 return err;
304
305 dsa_port_tag_8021q_vlan_del(dp, vid: standalone_vid, broadcast: false);
306
307 return 0;
308}
309EXPORT_SYMBOL_GPL(dsa_tag_8021q_bridge_join);
310
311void dsa_tag_8021q_bridge_leave(struct dsa_switch *ds, int port,
312 struct dsa_bridge bridge)
313{
314 struct dsa_port *dp = dsa_to_port(ds, p: port);
315 u16 standalone_vid, bridge_vid;
316 int err;
317
318 /* Delete the bridging VLAN of the port and replace it with a
319 * standalone VLAN
320 */
321 standalone_vid = dsa_tag_8021q_standalone_vid(dp);
322 bridge_vid = dsa_tag_8021q_bridge_vid(bridge.num);
323
324 err = dsa_port_tag_8021q_vlan_add(dp, vid: standalone_vid, broadcast: false);
325 if (err) {
326 dev_err(ds->dev,
327 "Failed to delete tag_8021q standalone VLAN %d from port %d: %pe\n",
328 standalone_vid, port, ERR_PTR(err));
329 }
330
331 dsa_port_tag_8021q_vlan_del(dp, vid: bridge_vid, broadcast: true);
332}
333EXPORT_SYMBOL_GPL(dsa_tag_8021q_bridge_leave);
334
335/* Set up a port's standalone tag_8021q VLAN */
336static int dsa_tag_8021q_port_setup(struct dsa_switch *ds, int port)
337{
338 struct dsa_8021q_context *ctx = ds->tag_8021q_ctx;
339 struct dsa_port *dp = dsa_to_port(ds, p: port);
340 u16 vid = dsa_tag_8021q_standalone_vid(dp);
341 struct net_device *conduit;
342 int err;
343
344 /* The CPU port is implicitly configured by
345 * configuring the front-panel ports
346 */
347 if (!dsa_port_is_user(dp))
348 return 0;
349
350 conduit = dsa_port_to_conduit(dp);
351
352 err = dsa_port_tag_8021q_vlan_add(dp, vid, broadcast: false);
353 if (err) {
354 dev_err(ds->dev,
355 "Failed to apply standalone VID %d to port %d: %pe\n",
356 vid, port, ERR_PTR(err));
357 return err;
358 }
359
360 /* Add the VLAN to the conduit's RX filter. */
361 vlan_vid_add(dev: conduit, proto: ctx->proto, vid);
362
363 return err;
364}
365
366static void dsa_tag_8021q_port_teardown(struct dsa_switch *ds, int port)
367{
368 struct dsa_8021q_context *ctx = ds->tag_8021q_ctx;
369 struct dsa_port *dp = dsa_to_port(ds, p: port);
370 u16 vid = dsa_tag_8021q_standalone_vid(dp);
371 struct net_device *conduit;
372
373 /* The CPU port is implicitly configured by
374 * configuring the front-panel ports
375 */
376 if (!dsa_port_is_user(dp))
377 return;
378
379 conduit = dsa_port_to_conduit(dp);
380
381 dsa_port_tag_8021q_vlan_del(dp, vid, broadcast: false);
382
383 vlan_vid_del(dev: conduit, proto: ctx->proto, vid);
384}
385
386static int dsa_tag_8021q_setup(struct dsa_switch *ds)
387{
388 int err, port;
389
390 ASSERT_RTNL();
391
392 for (port = 0; port < ds->num_ports; port++) {
393 err = dsa_tag_8021q_port_setup(ds, port);
394 if (err < 0) {
395 dev_err(ds->dev,
396 "Failed to setup VLAN tagging for port %d: %pe\n",
397 port, ERR_PTR(err));
398 return err;
399 }
400 }
401
402 return 0;
403}
404
405static void dsa_tag_8021q_teardown(struct dsa_switch *ds)
406{
407 int port;
408
409 ASSERT_RTNL();
410
411 for (port = 0; port < ds->num_ports; port++)
412 dsa_tag_8021q_port_teardown(ds, port);
413}
414
415int dsa_tag_8021q_register(struct dsa_switch *ds, __be16 proto)
416{
417 struct dsa_8021q_context *ctx;
418 int err;
419
420 ctx = kzalloc(size: sizeof(*ctx), GFP_KERNEL);
421 if (!ctx)
422 return -ENOMEM;
423
424 ctx->proto = proto;
425 ctx->ds = ds;
426
427 INIT_LIST_HEAD(list: &ctx->vlans);
428
429 ds->tag_8021q_ctx = ctx;
430
431 err = dsa_tag_8021q_setup(ds);
432 if (err)
433 goto err_free;
434
435 return 0;
436
437err_free:
438 kfree(objp: ctx);
439 return err;
440}
441EXPORT_SYMBOL_GPL(dsa_tag_8021q_register);
442
443void dsa_tag_8021q_unregister(struct dsa_switch *ds)
444{
445 struct dsa_8021q_context *ctx = ds->tag_8021q_ctx;
446 struct dsa_tag_8021q_vlan *v, *n;
447
448 dsa_tag_8021q_teardown(ds);
449
450 list_for_each_entry_safe(v, n, &ctx->vlans, list) {
451 list_del(entry: &v->list);
452 kfree(objp: v);
453 }
454
455 ds->tag_8021q_ctx = NULL;
456
457 kfree(objp: ctx);
458}
459EXPORT_SYMBOL_GPL(dsa_tag_8021q_unregister);
460
461struct sk_buff *dsa_8021q_xmit(struct sk_buff *skb, struct net_device *netdev,
462 u16 tpid, u16 tci)
463{
464 /* skb->data points at the MAC header, which is fine
465 * for vlan_insert_tag().
466 */
467 return vlan_insert_tag(skb, htons(tpid), vlan_tci: tci);
468}
469EXPORT_SYMBOL_GPL(dsa_8021q_xmit);
470
471struct net_device *dsa_tag_8021q_find_port_by_vbid(struct net_device *conduit,
472 int vbid)
473{
474 struct dsa_port *cpu_dp = conduit->dsa_ptr;
475 struct dsa_switch_tree *dst = cpu_dp->dst;
476 struct dsa_port *dp;
477
478 if (WARN_ON(!vbid))
479 return NULL;
480
481 dsa_tree_for_each_user_port(dp, dst) {
482 if (!dp->bridge)
483 continue;
484
485 if (dp->stp_state != BR_STATE_LEARNING &&
486 dp->stp_state != BR_STATE_FORWARDING)
487 continue;
488
489 if (dp->cpu_dp != cpu_dp)
490 continue;
491
492 if (dsa_port_bridge_num_get(dp) == vbid)
493 return dp->user;
494 }
495
496 return NULL;
497}
498EXPORT_SYMBOL_GPL(dsa_tag_8021q_find_port_by_vbid);
499
500void dsa_8021q_rcv(struct sk_buff *skb, int *source_port, int *switch_id,
501 int *vbid)
502{
503 u16 vid, tci;
504
505 if (skb_vlan_tag_present(skb)) {
506 tci = skb_vlan_tag_get(skb);
507 __vlan_hwaccel_clear_tag(skb);
508 } else {
509 skb_push_rcsum(skb, ETH_HLEN);
510 __skb_vlan_pop(skb, vlan_tci: &tci);
511 skb_pull_rcsum(skb, ETH_HLEN);
512 }
513
514 vid = tci & VLAN_VID_MASK;
515
516 *source_port = dsa_8021q_rx_source_port(vid);
517 *switch_id = dsa_8021q_rx_switch_id(vid);
518
519 if (vbid)
520 *vbid = dsa_tag_8021q_rx_vbid(vid);
521
522 skb->priority = (tci & VLAN_PRIO_MASK) >> VLAN_PRIO_SHIFT;
523}
524EXPORT_SYMBOL_GPL(dsa_8021q_rcv);
525

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