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 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_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 */ 50 static 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 */ 109 static inline struct net_device * 110 dsa_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 */ 156 static 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 */ 184 static 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 */ 213 static 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 */ 227 static 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 */ 236 static 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)) 249 250 void dsa_tag_drivers_register(struct dsa_tag_driver *dsa_tag_driver_array[], 251 unsigned int count, 252 struct module *owner); 253 void 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) \ 257 static 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 } \ 263 module_init(dsa_tag_driver_module_init); \ 264 \ 265 static void __exit dsa_tag_driver_module_exit(void) \ 266 { \ 267 dsa_tag_drivers_unregister(__dsa_tag_drivers_array, __count); \ 268 } \ 269 module_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) \ 281 dsa_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) \ 289 static 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) \ 303 DSA_TAG_DRIVER(__ops); \ 304 \ 305 static struct dsa_tag_driver *dsa_tag_driver_array[] = { \ 306 &DSA_TAG_DRIVER_NAME(__ops) \ 307 }; \ 308 module_dsa_tag_drivers(dsa_tag_driver_array) 309 310 #endif 311