tag.h

  1/* SPDX-License-Identifier: GPL-2.0-or-later */
  2
  3#ifndef __DSA_TAG_H
  4#define __DSA_TAG_H
  5
  6#include <linux/if_vlan.h>
  7#include <linux/list.h>
  8#include <linux/types.h>
  9#include <net/dsa.h>
 10
 11#include "port.h"
 12#include "user.h"
 13
 14struct dsa_tag_driver {
 15	const struct dsa_device_ops *ops;
 16	struct list_head list;
 17	struct module *owner;
 18};
 19
 20extern struct packet_type dsa_pack_type;
 21
 22const struct dsa_device_ops *dsa_tag_driver_get_by_id(int tag_protocol);
 23const struct dsa_device_ops *dsa_tag_driver_get_by_name(const char *name);
 24void dsa_tag_driver_put(const struct dsa_device_ops *ops);
 25const char *dsa_tag_protocol_to_str(const struct dsa_device_ops *ops);
 26
 27static inline int dsa_tag_protocol_overhead(const struct dsa_device_ops *ops)
 28{
 29	return ops->needed_headroom + ops->needed_tailroom;
 30}
 31
 32static inline struct net_device *dsa_conduit_find_user(struct net_device *dev,
 33						       int device, int port)
 34{
 35	struct dsa_port *cpu_dp = dev->dsa_ptr;
 36	struct dsa_switch_tree *dst = cpu_dp->dst;
 37	struct dsa_port *dp;
 38
 39	list_for_each_entry(dp, &dst->ports, list)
 40		if (dp->ds->index == device && dp->index == port &&
 41		    dp->type == DSA_PORT_TYPE_USER)
 42			return dp->user;
 43
 44	return NULL;
 45}
 46
 47/**
 48 * dsa_software_untag_vlan_aware_bridge: Software untagging for VLAN-aware bridge
 49 * @skb: Pointer to received socket buffer (packet)
 50 * @br: Pointer to bridge upper interface of ingress port
 51 * @vid: Parsed VID from packet
 52 *
 53 * The bridge can process tagged packets. Software like STP/PTP may not. The
 54 * bridge can also process untagged packets, to the same effect as if they were
 55 * tagged with the PVID of the ingress port. So packets tagged with the PVID of
 56 * the bridge port must be software-untagged, to support both use cases.
 57 */
 58static inline void dsa_software_untag_vlan_aware_bridge(struct sk_buff *skb,
 59							struct net_device *br,
 60							u16 vid)
 61{
 62	u16 pvid, proto;
 63	int err;
 64
 65	err = br_vlan_get_proto(br, &proto);
 66	if (err)
 67		return;
 68
 69	err = br_vlan_get_pvid_rcu(skb->dev, &pvid);
 70	if (err)
 71		return;
 72
 73	if (vid == pvid && skb->vlan_proto == htons(proto))
 74		__vlan_hwaccel_clear_tag(skb);
 75}
 76
 77/**
 78 * dsa_software_untag_vlan_unaware_bridge: Software untagging for VLAN-unaware bridge
 79 * @skb: Pointer to received socket buffer (packet)
 80 * @br: Pointer to bridge upper interface of ingress port
 81 * @vid: Parsed VID from packet
 82 *
 83 * The bridge ignores all VLAN tags. Software like STP/PTP may not (it may run
 84 * on the plain port, or on a VLAN upper interface). Maybe packets are coming
 85 * to software as tagged with a driver-defined VID which is NOT equal to the
 86 * PVID of the bridge port (since the bridge is VLAN-unaware, its configuration
 87 * should NOT be committed to hardware). DSA needs a method for this private
 88 * VID to be communicated by software to it, and if packets are tagged with it,
 89 * software-untag them. Note: the private VID may be different per bridge, to
 90 * support the FDB isolation use case.
 91 *
 92 * FIXME: this is currently implemented based on the broken assumption that
 93 * the "private VID" used by the driver in VLAN-unaware mode is equal to the
 94 * bridge PVID. It should not be, except for a coincidence; the bridge PVID is
 95 * irrelevant to the data path in the VLAN-unaware mode. Thus, the VID that
 96 * this function removes is wrong.
 97 *
 98 * All users of ds->untag_bridge_pvid should fix their drivers, if necessary,
 99 * to make the two independent. Only then, if there still remains a need to
100 * strip the private VID from packets, then a new ds->ops->get_private_vid()
101 * API shall be introduced to communicate to DSA what this VID is, which needs
102 * to be stripped here.
103 */
104static inline void dsa_software_untag_vlan_unaware_bridge(struct sk_buff *skb,
105							  struct net_device *br,
106							  u16 vid)
107{
108	struct net_device *upper_dev;
109	u16 pvid, proto;
110	int err;
111
112	err = br_vlan_get_proto(br, &proto);
113	if (err)
114		return;
115
116	err = br_vlan_get_pvid_rcu(skb->dev, &pvid);
117	if (err)
118		return;
119
120	if (vid != pvid || skb->vlan_proto != htons(proto))
121		return;
122
123	/* The sad part about attempting to untag from DSA is that we
124	 * don't know, unless we check, if the skb will end up in
125	 * the bridge's data path - br_allowed_ingress() - or not.
126	 * For example, there might be an 8021q upper for the
127	 * default_pvid of the bridge, which will steal VLAN-tagged traffic
128	 * from the bridge's data path. This is a configuration that DSA
129	 * supports because vlan_filtering is 0. In that case, we should
130	 * definitely keep the tag, to make sure it keeps working.
131	 */
132	upper_dev = __vlan_find_dev_deep_rcu(br, htons(proto), vid);
133	if (!upper_dev)
134		__vlan_hwaccel_clear_tag(skb);
135}
136
137/**
138 * dsa_software_vlan_untag: Software VLAN untagging in DSA receive path
139 * @skb: Pointer to socket buffer (packet)
140 *
141 * Receive path method for switches which send some packets as VLAN-tagged
142 * towards the CPU port (generally from VLAN-aware bridge ports) even when the
143 * packet was not tagged on the wire. Called when ds->untag_bridge_pvid
144 * (legacy) or ds->untag_vlan_aware_bridge_pvid is set to true.
145 *
146 * As a side effect of this method, any VLAN tag from the skb head is moved
147 * to hwaccel.
148 */
149static inline struct sk_buff *dsa_software_vlan_untag(struct sk_buff *skb)
150{
151	struct dsa_port *dp = dsa_user_to_port(skb->dev);
152	struct net_device *br = dsa_port_bridge_dev_get(dp);
153	u16 vid, proto;
154	int err;
155
156	/* software untagging for standalone ports not yet necessary */
157	if (!br)
158		return skb;
159
160	err = br_vlan_get_proto(br, &proto);
161	if (err)
162		return skb;
163
164	/* Move VLAN tag from data to hwaccel */
165	if (!skb_vlan_tag_present(skb) && skb->protocol == htons(proto)) {
166		skb = skb_vlan_untag(skb);
167		if (!skb)
168			return NULL;
169	}
170
171	if (!skb_vlan_tag_present(skb))
172		return skb;
173
174	vid = skb_vlan_tag_get_id(skb);
175
176	if (br_vlan_enabled(br)) {
177		if (dp->ds->untag_vlan_aware_bridge_pvid)
178			dsa_software_untag_vlan_aware_bridge(skb, br, vid);
179	} else {
180		if (dp->ds->untag_bridge_pvid)
181			dsa_software_untag_vlan_unaware_bridge(skb, br, vid);
182	}
183
184	return skb;
185}
186
187/* For switches without hardware support for DSA tagging to be able
188 * to support termination through the bridge.
189 */
190static inline struct net_device *
191dsa_find_designated_bridge_port_by_vid(struct net_device *conduit, u16 vid)
192{
193	struct dsa_port *cpu_dp = conduit->dsa_ptr;
194	struct dsa_switch_tree *dst = cpu_dp->dst;
195	struct bridge_vlan_info vinfo;
196	struct net_device *user;
197	struct dsa_port *dp;
198	int err;
199
200	list_for_each_entry(dp, &dst->ports, list) {
201		if (dp->type != DSA_PORT_TYPE_USER)
202			continue;
203
204		if (!dp->bridge)
205			continue;
206
207		if (dp->stp_state != BR_STATE_LEARNING &&
208		    dp->stp_state != BR_STATE_FORWARDING)
209			continue;
210
211		/* Since the bridge might learn this packet, keep the CPU port
212		 * affinity with the port that will be used for the reply on
213		 * xmit.
214		 */
215		if (dp->cpu_dp != cpu_dp)
216			continue;
217
218		user = dp->user;
219
220		err = br_vlan_get_info_rcu(user, vid, &vinfo);
221		if (err)
222			continue;
223
224		return user;
225	}
226
227	return NULL;
228}
229
230/* If the ingress port offloads the bridge, we mark the frame as autonomously
231 * forwarded by hardware, so the software bridge doesn't forward in twice, back
232 * to us, because we already did. However, if we're in fallback mode and we do
233 * software bridging, we are not offloading it, therefore the dp->bridge
234 * pointer is not populated, and flooding needs to be done by software (we are
235 * effectively operating in standalone ports mode).
236 */
237static inline void dsa_default_offload_fwd_mark(struct sk_buff *skb)
238{
239	struct dsa_port *dp = dsa_user_to_port(skb->dev);
240
241	skb->offload_fwd_mark = !!(dp->bridge);
242}
243
244/* Helper for removing DSA header tags from packets in the RX path.
245 * Must not be called before skb_pull(len).
246 *                                                                 skb->data
247 *                                                                         |
248 *                                                                         v
249 * |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |
250 * +-----------------------+-----------------------+---------------+-------+
251 * |    Destination MAC    |      Source MAC       |  DSA header   | EType |
252 * +-----------------------+-----------------------+---------------+-------+
253 *                                                 |               |
254 * <----- len ----->                               <----- len ----->
255 *                 |
256 *       >>>>>>>   v
257 *       >>>>>>>   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |
258 *       >>>>>>>   +-----------------------+-----------------------+-------+
259 *       >>>>>>>   |    Destination MAC    |      Source MAC       | EType |
260 *                 +-----------------------+-----------------------+-------+
261 *                                                                         ^
262 *                                                                         |
263 *                                                                 skb->data
264 */
265static inline void dsa_strip_etype_header(struct sk_buff *skb, int len)
266{
267	memmove(skb->data - ETH_HLEN, skb->data - ETH_HLEN - len, 2 * ETH_ALEN);
268}
269
270/* Helper for creating space for DSA header tags in TX path packets.
271 * Must not be called before skb_push(len).
272 *
273 * Before:
274 *
275 *       <<<<<<<   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |
276 * ^     <<<<<<<   +-----------------------+-----------------------+-------+
277 * |     <<<<<<<   |    Destination MAC    |      Source MAC       | EType |
278 * |               +-----------------------+-----------------------+-------+
279 * <----- len ----->
280 * |
281 * |
282 * skb->data
283 *
284 * After:
285 *
286 * |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |
287 * +-----------------------+-----------------------+---------------+-------+
288 * |    Destination MAC    |      Source MAC       |  DSA header   | EType |
289 * +-----------------------+-----------------------+---------------+-------+
290 * ^                                               |               |
291 * |                                               <----- len ----->
292 * skb->data
293 */
294static inline void dsa_alloc_etype_header(struct sk_buff *skb, int len)
295{
296	memmove(skb->data, skb->data + len, 2 * ETH_ALEN);
297}
298
299/* On RX, eth_type_trans() on the DSA conduit pulls ETH_HLEN bytes starting from
300 * skb_mac_header(skb), which leaves skb->data pointing at the first byte after
301 * what the DSA conduit perceives as the EtherType (the beginning of the L3
302 * protocol). Since DSA EtherType header taggers treat the EtherType as part of
303 * the DSA tag itself, and the EtherType is 2 bytes in length, the DSA header
304 * is located 2 bytes behind skb->data. Note that EtherType in this context
305 * means the first 2 bytes of the DSA header, not the encapsulated EtherType
306 * that will become visible after the DSA header is stripped.
307 */
308static inline void *dsa_etype_header_pos_rx(struct sk_buff *skb)
309{
310	return skb->data - 2;
311}
312
313/* On TX, skb->data points to the MAC header, which means that EtherType
314 * header taggers start exactly where the EtherType is (the EtherType is
315 * treated as part of the DSA header).
316 */
317static inline void *dsa_etype_header_pos_tx(struct sk_buff *skb)
318{
319	return skb->data + 2 * ETH_ALEN;
320}
321
322static inline unsigned long dsa_xmit_port_mask(const struct sk_buff *skb,
323					       const struct net_device *dev)
324{
325	struct dsa_port *dp = dsa_user_to_port(dev);
326	unsigned long mask = BIT(dp->index);
327
328	if (IS_ENABLED(CONFIG_HSR) &&
329	    unlikely(dev->features & NETIF_F_HW_HSR_DUP)) {
330		struct net_device *hsr_dev = dp->hsr_dev;
331		struct dsa_port *other_dp;
332
333		dsa_hsr_foreach_port(other_dp, dp->ds, hsr_dev)
334			mask |= BIT(other_dp->index);
335	}
336
337	return mask;
338}
339
340/* Create 2 modaliases per tagging protocol, one to auto-load the module
341 * given the ID reported by get_tag_protocol(), and the other by name.
342 */
343#define DSA_TAG_DRIVER_ALIAS "dsa_tag:"
344#define MODULE_ALIAS_DSA_TAG_DRIVER(__proto, __name) \
345	MODULE_ALIAS(DSA_TAG_DRIVER_ALIAS __name); \
346	MODULE_ALIAS(DSA_TAG_DRIVER_ALIAS "id-" \
347		     __stringify(__proto##_VALUE))
348
349void dsa_tag_drivers_register(struct dsa_tag_driver *dsa_tag_driver_array[],
350			      unsigned int count,
351			      struct module *owner);
352void dsa_tag_drivers_unregister(struct dsa_tag_driver *dsa_tag_driver_array[],
353				unsigned int count);
354
355#define dsa_tag_driver_module_drivers(__dsa_tag_drivers_array, __count)	\
356static int __init dsa_tag_driver_module_init(void)			\
357{									\
358	dsa_tag_drivers_register(__dsa_tag_drivers_array, __count,	\
359				 THIS_MODULE);				\
360	return 0;							\
361}									\
362module_init(dsa_tag_driver_module_init);				\
363									\
364static void __exit dsa_tag_driver_module_exit(void)			\
365{									\
366	dsa_tag_drivers_unregister(__dsa_tag_drivers_array, __count);	\
367}									\
368module_exit(dsa_tag_driver_module_exit)
369
370/**
371 * module_dsa_tag_drivers() - Helper macro for registering DSA tag
372 * drivers
373 * @__ops_array: Array of tag driver structures
374 *
375 * Helper macro for DSA tag drivers which do not do anything special
376 * in module init/exit. Each module may only use this macro once, and
377 * calling it replaces module_init() and module_exit().
378 */
379#define module_dsa_tag_drivers(__ops_array)				\
380dsa_tag_driver_module_drivers(__ops_array, ARRAY_SIZE(__ops_array))
381
382#define DSA_TAG_DRIVER_NAME(__ops) dsa_tag_driver ## _ ## __ops
383
384/* Create a static structure we can build a linked list of dsa_tag
385 * drivers
386 */
387#define DSA_TAG_DRIVER(__ops)						\
388static struct dsa_tag_driver DSA_TAG_DRIVER_NAME(__ops) = {		\
389	.ops = &__ops,							\
390}
391
392/**
393 * module_dsa_tag_driver() - Helper macro for registering a single DSA tag
394 * driver
395 * @__ops: Single tag driver structures
396 *
397 * Helper macro for DSA tag drivers which do not do anything special
398 * in module init/exit. Each module may only use this macro once, and
399 * calling it replaces module_init() and module_exit().
400 */
401#define module_dsa_tag_driver(__ops)					\
402DSA_TAG_DRIVER(__ops);							\
403									\
404static struct dsa_tag_driver *dsa_tag_driver_array[] =	{		\
405	&DSA_TAG_DRIVER_NAME(__ops)					\
406};									\
407module_dsa_tag_drivers(dsa_tag_driver_array)
408
409#endif