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
14 struct dsa_tag_driver {
15 const struct dsa_device_ops *ops;
16 struct list_head list;
17 struct module *owner;
18 };
19
20 extern struct packet_type dsa_pack_type;
21
22 const struct dsa_device_ops *dsa_tag_driver_get_by_id(int tag_protocol);
23 const struct dsa_device_ops *dsa_tag_driver_get_by_name(const char *name);
24 void dsa_tag_driver_put(const struct dsa_device_ops *ops);
25 const char *dsa_tag_protocol_to_str(const struct dsa_device_ops *ops);
26
dsa_tag_protocol_overhead(const struct dsa_device_ops * ops)27 static inline int dsa_tag_protocol_overhead(const struct dsa_device_ops *ops)
28 {
29 return ops->needed_headroom + ops->needed_tailroom;
30 }
31
dsa_conduit_find_user(struct net_device * dev,int device,int port)32 static 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 */
dsa_software_untag_vlan_aware_bridge(struct sk_buff * skb,struct net_device * br,u16 vid)58 static 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 */
dsa_software_untag_vlan_unaware_bridge(struct sk_buff * skb,struct net_device * br,u16 vid)104 static 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 cannot avoid tagging all packets
142 * towards the CPU port. Called when ds->untag_bridge_pvid (legacy) or
143 * ds->untag_vlan_aware_bridge_pvid is set to true.
144 *
145 * As a side effect of this method, any VLAN tag from the skb head is moved
146 * to hwaccel.
147 */
dsa_software_vlan_untag(struct sk_buff * skb)148 static inline struct sk_buff *dsa_software_vlan_untag(struct sk_buff *skb)
149 {
150 struct dsa_port *dp = dsa_user_to_port(skb->dev);
151 struct net_device *br = dsa_port_bridge_dev_get(dp);
152 u16 vid;
153
154 /* software untagging for standalone ports not yet necessary */
155 if (!br)
156 return skb;
157
158 /* Move VLAN tag from data to hwaccel */
159 if (!skb_vlan_tag_present(skb)) {
160 skb = skb_vlan_untag(skb);
161 if (!skb)
162 return NULL;
163 }
164
165 if (!skb_vlan_tag_present(skb))
166 return skb;
167
168 vid = skb_vlan_tag_get_id(skb);
169
170 if (br_vlan_enabled(br)) {
171 if (dp->ds->untag_vlan_aware_bridge_pvid)
172 dsa_software_untag_vlan_aware_bridge(skb, br, vid);
173 } else {
174 if (dp->ds->untag_bridge_pvid)
175 dsa_software_untag_vlan_unaware_bridge(skb, br, vid);
176 }
177
178 return skb;
179 }
180
181 /* For switches without hardware support for DSA tagging to be able
182 * to support termination through the bridge.
183 */
184 static inline struct net_device *
dsa_find_designated_bridge_port_by_vid(struct net_device * conduit,u16 vid)185 dsa_find_designated_bridge_port_by_vid(struct net_device *conduit, u16 vid)
186 {
187 struct dsa_port *cpu_dp = conduit->dsa_ptr;
188 struct dsa_switch_tree *dst = cpu_dp->dst;
189 struct bridge_vlan_info vinfo;
190 struct net_device *user;
191 struct dsa_port *dp;
192 int err;
193
194 list_for_each_entry(dp, &dst->ports, list) {
195 if (dp->type != DSA_PORT_TYPE_USER)
196 continue;
197
198 if (!dp->bridge)
199 continue;
200
201 if (dp->stp_state != BR_STATE_LEARNING &&
202 dp->stp_state != BR_STATE_FORWARDING)
203 continue;
204
205 /* Since the bridge might learn this packet, keep the CPU port
206 * affinity with the port that will be used for the reply on
207 * xmit.
208 */
209 if (dp->cpu_dp != cpu_dp)
210 continue;
211
212 user = dp->user;
213
214 err = br_vlan_get_info_rcu(user, vid, &vinfo);
215 if (err)
216 continue;
217
218 return user;
219 }
220
221 return NULL;
222 }
223
224 /* If the ingress port offloads the bridge, we mark the frame as autonomously
225 * forwarded by hardware, so the software bridge doesn't forward in twice, back
226 * to us, because we already did. However, if we're in fallback mode and we do
227 * software bridging, we are not offloading it, therefore the dp->bridge
228 * pointer is not populated, and flooding needs to be done by software (we are
229 * effectively operating in standalone ports mode).
230 */
dsa_default_offload_fwd_mark(struct sk_buff * skb)231 static inline void dsa_default_offload_fwd_mark(struct sk_buff *skb)
232 {
233 struct dsa_port *dp = dsa_user_to_port(skb->dev);
234
235 skb->offload_fwd_mark = !!(dp->bridge);
236 }
237
238 /* Helper for removing DSA header tags from packets in the RX path.
239 * Must not be called before skb_pull(len).
240 * skb->data
241 * |
242 * v
243 * | | | | | | | | | | | | | | | | | | |
244 * +-----------------------+-----------------------+---------------+-------+
245 * | Destination MAC | Source MAC | DSA header | EType |
246 * +-----------------------+-----------------------+---------------+-------+
247 * | |
248 * <----- len -----> <----- len ----->
249 * |
250 * >>>>>>> v
251 * >>>>>>> | | | | | | | | | | | | | | |
252 * >>>>>>> +-----------------------+-----------------------+-------+
253 * >>>>>>> | Destination MAC | Source MAC | EType |
254 * +-----------------------+-----------------------+-------+
255 * ^
256 * |
257 * skb->data
258 */
dsa_strip_etype_header(struct sk_buff * skb,int len)259 static inline void dsa_strip_etype_header(struct sk_buff *skb, int len)
260 {
261 memmove(skb->data - ETH_HLEN, skb->data - ETH_HLEN - len, 2 * ETH_ALEN);
262 }
263
264 /* Helper for creating space for DSA header tags in TX path packets.
265 * Must not be called before skb_push(len).
266 *
267 * Before:
268 *
269 * <<<<<<< | | | | | | | | | | | | | | |
270 * ^ <<<<<<< +-----------------------+-----------------------+-------+
271 * | <<<<<<< | Destination MAC | Source MAC | EType |
272 * | +-----------------------+-----------------------+-------+
273 * <----- len ----->
274 * |
275 * |
276 * skb->data
277 *
278 * After:
279 *
280 * | | | | | | | | | | | | | | | | | | |
281 * +-----------------------+-----------------------+---------------+-------+
282 * | Destination MAC | Source MAC | DSA header | EType |
283 * +-----------------------+-----------------------+---------------+-------+
284 * ^ | |
285 * | <----- len ----->
286 * skb->data
287 */
dsa_alloc_etype_header(struct sk_buff * skb,int len)288 static inline void dsa_alloc_etype_header(struct sk_buff *skb, int len)
289 {
290 memmove(skb->data, skb->data + len, 2 * ETH_ALEN);
291 }
292
293 /* On RX, eth_type_trans() on the DSA conduit pulls ETH_HLEN bytes starting from
294 * skb_mac_header(skb), which leaves skb->data pointing at the first byte after
295 * what the DSA conduit perceives as the EtherType (the beginning of the L3
296 * protocol). Since DSA EtherType header taggers treat the EtherType as part of
297 * the DSA tag itself, and the EtherType is 2 bytes in length, the DSA header
298 * is located 2 bytes behind skb->data. Note that EtherType in this context
299 * means the first 2 bytes of the DSA header, not the encapsulated EtherType
300 * that will become visible after the DSA header is stripped.
301 */
dsa_etype_header_pos_rx(struct sk_buff * skb)302 static inline void *dsa_etype_header_pos_rx(struct sk_buff *skb)
303 {
304 return skb->data - 2;
305 }
306
307 /* On TX, skb->data points to the MAC header, which means that EtherType
308 * header taggers start exactly where the EtherType is (the EtherType is
309 * treated as part of the DSA header).
310 */
dsa_etype_header_pos_tx(struct sk_buff * skb)311 static inline void *dsa_etype_header_pos_tx(struct sk_buff *skb)
312 {
313 return skb->data + 2 * ETH_ALEN;
314 }
315
316 /* Create 2 modaliases per tagging protocol, one to auto-load the module
317 * given the ID reported by get_tag_protocol(), and the other by name.
318 */
319 #define DSA_TAG_DRIVER_ALIAS "dsa_tag:"
320 #define MODULE_ALIAS_DSA_TAG_DRIVER(__proto, __name) \
321 MODULE_ALIAS(DSA_TAG_DRIVER_ALIAS __name); \
322 MODULE_ALIAS(DSA_TAG_DRIVER_ALIAS "id-" \
323 __stringify(__proto##_VALUE))
324
325 void dsa_tag_drivers_register(struct dsa_tag_driver *dsa_tag_driver_array[],
326 unsigned int count,
327 struct module *owner);
328 void dsa_tag_drivers_unregister(struct dsa_tag_driver *dsa_tag_driver_array[],
329 unsigned int count);
330
331 #define dsa_tag_driver_module_drivers(__dsa_tag_drivers_array, __count) \
332 static int __init dsa_tag_driver_module_init(void) \
333 { \
334 dsa_tag_drivers_register(__dsa_tag_drivers_array, __count, \
335 THIS_MODULE); \
336 return 0; \
337 } \
338 module_init(dsa_tag_driver_module_init); \
339 \
340 static void __exit dsa_tag_driver_module_exit(void) \
341 { \
342 dsa_tag_drivers_unregister(__dsa_tag_drivers_array, __count); \
343 } \
344 module_exit(dsa_tag_driver_module_exit)
345
346 /**
347 * module_dsa_tag_drivers() - Helper macro for registering DSA tag
348 * drivers
349 * @__ops_array: Array of tag driver structures
350 *
351 * Helper macro for DSA tag drivers which do not do anything special
352 * in module init/exit. Each module may only use this macro once, and
353 * calling it replaces module_init() and module_exit().
354 */
355 #define module_dsa_tag_drivers(__ops_array) \
356 dsa_tag_driver_module_drivers(__ops_array, ARRAY_SIZE(__ops_array))
357
358 #define DSA_TAG_DRIVER_NAME(__ops) dsa_tag_driver ## _ ## __ops
359
360 /* Create a static structure we can build a linked list of dsa_tag
361 * drivers
362 */
363 #define DSA_TAG_DRIVER(__ops) \
364 static struct dsa_tag_driver DSA_TAG_DRIVER_NAME(__ops) = { \
365 .ops = &__ops, \
366 }
367
368 /**
369 * module_dsa_tag_driver() - Helper macro for registering a single DSA tag
370 * driver
371 * @__ops: Single tag driver structures
372 *
373 * Helper macro for DSA tag drivers which do not do anything special
374 * in module init/exit. Each module may only use this macro once, and
375 * calling it replaces module_init() and module_exit().
376 */
377 #define module_dsa_tag_driver(__ops) \
378 DSA_TAG_DRIVER(__ops); \
379 \
380 static struct dsa_tag_driver *dsa_tag_driver_array[] = { \
381 &DSA_TAG_DRIVER_NAME(__ops) \
382 }; \
383 module_dsa_tag_drivers(dsa_tag_driver_array)
384
385 #endif
386