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 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 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 */ 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 */ 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 */ 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 * 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 */ 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 */ 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 */ 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 */ 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 */ 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