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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 "slave.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_master_find_slave(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->slave;
43
44 return NULL;
45}
46
47/* If under a bridge with vlan_filtering=0, make sure to send pvid-tagged
48 * frames as untagged, since the bridge will not untag them.
49 */
50static inline struct sk_buff *dsa_untag_bridge_pvid(struct sk_buff *skb)
51{
52 struct dsa_port *dp = dsa_slave_to_port(skb->dev);
53 struct net_device *br = dsa_port_bridge_dev_get(dp);
54 struct net_device *dev = skb->dev;
55 struct net_device *upper_dev;
56 u16 vid, pvid, proto;
57 int err;
58
59 if (!br || br_vlan_enabled(br))
60 return skb;
61
62 err = br_vlan_get_proto(br, &proto);
63 if (err)
64 return skb;
65
66 /* Move VLAN tag from data to hwaccel */
67 if (!skb_vlan_tag_present(skb) && skb->protocol == htons(proto)) {
68 skb = skb_vlan_untag(skb);
69 if (!skb)
70 return NULL;
71 }
72
73 if (!skb_vlan_tag_present(skb))
74 return skb;
75
76 vid = skb_vlan_tag_get_id(skb);
77
78 /* We already run under an RCU read-side critical section since
79 * we are called from netif_receive_skb_list_internal().
80 */
81 err = br_vlan_get_pvid_rcu(dev, &pvid);
82 if (err)
83 return skb;
84
85 if (vid != pvid)
86 return skb;
87
88 /* The sad part about attempting to untag from DSA is that we
89 * don't know, unless we check, if the skb will end up in
90 * the bridge's data path - br_allowed_ingress() - or not.
91 * For example, there might be an 8021q upper for the
92 * default_pvid of the bridge, which will steal VLAN-tagged traffic
93 * from the bridge's data path. This is a configuration that DSA
94 * supports because vlan_filtering is 0. In that case, we should
95 * definitely keep the tag, to make sure it keeps working.
96 */
97 upper_dev = __vlan_find_dev_deep_rcu(br, htons(proto), vid);
98 if (upper_dev)
99 return skb;
100
101 __vlan_hwaccel_clear_tag(skb);
102
103 return skb;
104}
105
106/* For switches without hardware support for DSA tagging to be able
107 * to support termination through the bridge.
108 */
109static inline struct net_device *
110dsa_find_designated_bridge_port_by_vid(struct net_device *master, u16 vid)
111{
112 struct dsa_port *cpu_dp = master->dsa_ptr;
113 struct dsa_switch_tree *dst = cpu_dp->dst;
114 struct bridge_vlan_info vinfo;
115 struct net_device *slave;
116 struct dsa_port *dp;
117 int err;
118
119 list_for_each_entry(dp, &dst->ports, list) {
120 if (dp->type != DSA_PORT_TYPE_USER)
121 continue;
122
123 if (!dp->bridge)
124 continue;
125
126 if (dp->stp_state != BR_STATE_LEARNING &&
127 dp->stp_state != BR_STATE_FORWARDING)
128 continue;
129
130 /* Since the bridge might learn this packet, keep the CPU port
131 * affinity with the port that will be used for the reply on
132 * xmit.
133 */
134 if (dp->cpu_dp != cpu_dp)
135 continue;
136
137 slave = dp->slave;
138
139 err = br_vlan_get_info_rcu(slave, vid, &vinfo);
140 if (err)
141 continue;
142
143 return slave;
144 }
145
146 return NULL;
147}
148
149/* If the ingress port offloads the bridge, we mark the frame as autonomously
150 * forwarded by hardware, so the software bridge doesn't forward in twice, back
151 * to us, because we already did. However, if we're in fallback mode and we do
152 * software bridging, we are not offloading it, therefore the dp->bridge
153 * pointer is not populated, and flooding needs to be done by software (we are
154 * effectively operating in standalone ports mode).
155 */
156static inline void dsa_default_offload_fwd_mark(struct sk_buff *skb)
157{
158 struct dsa_port *dp = dsa_slave_to_port(skb->dev);
159
160 skb->offload_fwd_mark = !!(dp->bridge);
161}
162
163/* Helper for removing DSA header tags from packets in the RX path.
164 * Must not be called before skb_pull(len).
165 * skb->data
166 * |
167 * v
168 * | | | | | | | | | | | | | | | | | | |
169 * +-----------------------+-----------------------+---------------+-------+
170 * | Destination MAC | Source MAC | DSA header | EType |
171 * +-----------------------+-----------------------+---------------+-------+
172 * | |
173 * <----- len -----> <----- len ----->
174 * |
175 * >>>>>>> v
176 * >>>>>>> | | | | | | | | | | | | | | |
177 * >>>>>>> +-----------------------+-----------------------+-------+
178 * >>>>>>> | Destination MAC | Source MAC | EType |
179 * +-----------------------+-----------------------+-------+
180 * ^
181 * |
182 * skb->data
183 */
184static inline void dsa_strip_etype_header(struct sk_buff *skb, int len)
185{
186 memmove(skb->data - ETH_HLEN, skb->data - ETH_HLEN - len, 2 * ETH_ALEN);
187}
188
189/* Helper for creating space for DSA header tags in TX path packets.
190 * Must not be called before skb_push(len).
191 *
192 * Before:
193 *
194 * <<<<<<< | | | | | | | | | | | | | | |
195 * ^ <<<<<<< +-----------------------+-----------------------+-------+
196 * | <<<<<<< | Destination MAC | Source MAC | EType |
197 * | +-----------------------+-----------------------+-------+
198 * <----- len ----->
199 * |
200 * |
201 * skb->data
202 *
203 * After:
204 *
205 * | | | | | | | | | | | | | | | | | | |
206 * +-----------------------+-----------------------+---------------+-------+
207 * | Destination MAC | Source MAC | DSA header | EType |
208 * +-----------------------+-----------------------+---------------+-------+
209 * ^ | |
210 * | <----- len ----->
211 * skb->data
212 */
213static inline void dsa_alloc_etype_header(struct sk_buff *skb, int len)
214{
215 memmove(skb->data, skb->data + len, 2 * ETH_ALEN);
216}
217
218/* On RX, eth_type_trans() on the DSA master pulls ETH_HLEN bytes starting from
219 * skb_mac_header(skb), which leaves skb->data pointing at the first byte after
220 * what the DSA master perceives as the EtherType (the beginning of the L3
221 * protocol). Since DSA EtherType header taggers treat the EtherType as part of
222 * the DSA tag itself, and the EtherType is 2 bytes in length, the DSA header
223 * is located 2 bytes behind skb->data. Note that EtherType in this context
224 * means the first 2 bytes of the DSA header, not the encapsulated EtherType
225 * that will become visible after the DSA header is stripped.
226 */
227static inline void *dsa_etype_header_pos_rx(struct sk_buff *skb)
228{
229 return skb->data - 2;
230}
231
232/* On TX, skb->data points to skb_mac_header(skb), which means that EtherType
233 * header taggers start exactly where the EtherType is (the EtherType is
234 * treated as part of the DSA header).
235 */
236static inline void *dsa_etype_header_pos_tx(struct sk_buff *skb)
237{
238 return skb->data + 2 * ETH_ALEN;
239}
240
241/* Create 2 modaliases per tagging protocol, one to auto-load the module
242 * given the ID reported by get_tag_protocol(), and the other by name.
243 */
244#define DSA_TAG_DRIVER_ALIAS "dsa_tag:"
245#define MODULE_ALIAS_DSA_TAG_DRIVER(__proto, __name) \
246 MODULE_ALIAS(DSA_TAG_DRIVER_ALIAS __name); \
247 MODULE_ALIAS(DSA_TAG_DRIVER_ALIAS "id-" \
248 __stringify(__proto##_VALUE))
249
250void dsa_tag_drivers_register(struct dsa_tag_driver *dsa_tag_driver_array[],
251 unsigned int count,
252 struct module *owner);
253void dsa_tag_drivers_unregister(struct dsa_tag_driver *dsa_tag_driver_array[],
254 unsigned int count);
255
256#define dsa_tag_driver_module_drivers(__dsa_tag_drivers_array, __count) \
257static int __init dsa_tag_driver_module_init(void) \
258{ \
259 dsa_tag_drivers_register(__dsa_tag_drivers_array, __count, \
260 THIS_MODULE); \
261 return 0; \
262} \
263module_init(dsa_tag_driver_module_init); \
264 \
265static void __exit dsa_tag_driver_module_exit(void) \
266{ \
267 dsa_tag_drivers_unregister(__dsa_tag_drivers_array, __count); \
268} \
269module_exit(dsa_tag_driver_module_exit)
270
271/**
272 * module_dsa_tag_drivers() - Helper macro for registering DSA tag
273 * drivers
274 * @__ops_array: Array of tag driver structures
275 *
276 * Helper macro for DSA tag drivers which do not do anything special
277 * in module init/exit. Each module may only use this macro once, and
278 * calling it replaces module_init() and module_exit().
279 */
280#define module_dsa_tag_drivers(__ops_array) \
281dsa_tag_driver_module_drivers(__ops_array, ARRAY_SIZE(__ops_array))
282
283#define DSA_TAG_DRIVER_NAME(__ops) dsa_tag_driver ## _ ## __ops
284
285/* Create a static structure we can build a linked list of dsa_tag
286 * drivers
287 */
288#define DSA_TAG_DRIVER(__ops) \
289static struct dsa_tag_driver DSA_TAG_DRIVER_NAME(__ops) = { \
290 .ops = &__ops, \
291}
292
293/**
294 * module_dsa_tag_driver() - Helper macro for registering a single DSA tag
295 * driver
296 * @__ops: Single tag driver structures
297 *
298 * Helper macro for DSA tag drivers which do not do anything special
299 * in module init/exit. Each module may only use this macro once, and
300 * calling it replaces module_init() and module_exit().
301 */
302#define module_dsa_tag_driver(__ops) \
303DSA_TAG_DRIVER(__ops); \
304 \
305static struct dsa_tag_driver *dsa_tag_driver_array[] = { \
306 &DSA_TAG_DRIVER_NAME(__ops) \
307}; \
308module_dsa_tag_drivers(dsa_tag_driver_array)
309
310#endif