1 // SPDX-License-Identifier: GPL-2.0+ 2 /* 3 * Regular and Ethertype DSA tagging 4 * Copyright (c) 2008-2009 Marvell Semiconductor 5 * 6 * Regular DSA 7 * ----------- 8 9 * For untagged (in 802.1Q terms) packets, the switch will splice in 10 * the tag between the SA and the ethertype of the original 11 * packet. Tagged frames will instead have their outermost .1Q tag 12 * converted to a DSA tag. It expects the same layout when receiving 13 * packets from the CPU. 14 * 15 * Example: 16 * 17 * .----.----.----.--------- 18 * Pu: | DA | SA | ET | Payload ... 19 * '----'----'----'--------- 20 * 6 6 2 N 21 * .----.----.--------.-----.----.--------- 22 * Pt: | DA | SA | 0x8100 | TCI | ET | Payload ... 23 * '----'----'--------'-----'----'--------- 24 * 6 6 2 2 2 N 25 * .----.----.-----.----.--------- 26 * Pd: | DA | SA | DSA | ET | Payload ... 27 * '----'----'-----'----'--------- 28 * 6 6 4 2 N 29 * 30 * No matter if a packet is received untagged (Pu) or tagged (Pt), 31 * they will both have the same layout (Pd) when they are sent to the 32 * CPU. This is done by ignoring 802.3, replacing the ethertype field 33 * with more metadata, among which is a bit to signal if the original 34 * packet was tagged or not. 35 * 36 * Ethertype DSA 37 * ------------- 38 * Uses the exact same tag format as regular DSA, but also includes a 39 * proper ethertype field (which the mv88e6xxx driver sets to 40 * ETH_P_EDSA/0xdada) followed by two zero bytes: 41 * 42 * .----.----.--------.--------.-----.----.--------- 43 * | DA | SA | 0xdada | 0x0000 | DSA | ET | Payload ... 44 * '----'----'--------'--------'-----'----'--------- 45 * 6 6 2 2 4 2 N 46 */ 47 48 #include <linux/dsa/mv88e6xxx.h> 49 #include <linux/etherdevice.h> 50 #include <linux/list.h> 51 #include <linux/slab.h> 52 53 #include "dsa_priv.h" 54 55 #define DSA_HLEN 4 56 57 /** 58 * enum dsa_cmd - DSA Command 59 * @DSA_CMD_TO_CPU: Set on packets that were trapped or mirrored to 60 * the CPU port. This is needed to implement control protocols, 61 * e.g. STP and LLDP, that must not allow those control packets to 62 * be switched according to the normal rules. 63 * @DSA_CMD_FROM_CPU: Used by the CPU to send a packet to a specific 64 * port, ignoring all the barriers that the switch normally 65 * enforces (VLANs, STP port states etc.). No source address 66 * learning takes place. "sudo send packet" 67 * @DSA_CMD_TO_SNIFFER: Set on the copies of packets that matched some 68 * user configured ingress or egress monitor criteria. These are 69 * forwarded by the switch tree to the user configured ingress or 70 * egress monitor port, which can be set to the CPU port or a 71 * regular port. If the destination is a regular port, the tag 72 * will be removed before egressing the port. If the destination 73 * is the CPU port, the tag will not be removed. 74 * @DSA_CMD_FORWARD: This tag is used on all bulk traffic passing 75 * through the switch tree, including the flows that are directed 76 * towards the CPU. Its device/port tuple encodes the original 77 * source port on which the packet ingressed. It can also be used 78 * on transmit by the CPU to defer the forwarding decision to the 79 * hardware, based on the current config of PVT/VTU/ATU 80 * etc. Source address learning takes places if enabled on the 81 * receiving DSA/CPU port. 82 */ 83 enum dsa_cmd { 84 DSA_CMD_TO_CPU = 0, 85 DSA_CMD_FROM_CPU = 1, 86 DSA_CMD_TO_SNIFFER = 2, 87 DSA_CMD_FORWARD = 3 88 }; 89 90 /** 91 * enum dsa_code - TO_CPU Code 92 * 93 * @DSA_CODE_MGMT_TRAP: DA was classified as a management 94 * address. Typical examples include STP BPDUs and LLDP. 95 * @DSA_CODE_FRAME2REG: Response to a "remote management" request. 96 * @DSA_CODE_IGMP_MLD_TRAP: IGMP/MLD signaling. 97 * @DSA_CODE_POLICY_TRAP: Frame matched some policy configuration on 98 * the device. Typical examples are matching on DA/SA/VID and DHCP 99 * snooping. 100 * @DSA_CODE_ARP_MIRROR: The name says it all really. 101 * @DSA_CODE_POLICY_MIRROR: Same as @DSA_CODE_POLICY_TRAP, but the 102 * particular policy was set to trigger a mirror instead of a 103 * trap. 104 * @DSA_CODE_RESERVED_6: Unused on all devices up to at least 6393X. 105 * @DSA_CODE_RESERVED_7: Unused on all devices up to at least 6393X. 106 * 107 * A 3-bit code is used to relay why a particular frame was sent to 108 * the CPU. We only use this to determine if the packet was mirrored 109 * or trapped, i.e. whether the packet has been forwarded by hardware 110 * or not. 111 * 112 * This is the superset of all possible codes. Any particular device 113 * may only implement a subset. 114 */ 115 enum dsa_code { 116 DSA_CODE_MGMT_TRAP = 0, 117 DSA_CODE_FRAME2REG = 1, 118 DSA_CODE_IGMP_MLD_TRAP = 2, 119 DSA_CODE_POLICY_TRAP = 3, 120 DSA_CODE_ARP_MIRROR = 4, 121 DSA_CODE_POLICY_MIRROR = 5, 122 DSA_CODE_RESERVED_6 = 6, 123 DSA_CODE_RESERVED_7 = 7 124 }; 125 126 static struct sk_buff *dsa_xmit_ll(struct sk_buff *skb, struct net_device *dev, 127 u8 extra) 128 { 129 struct dsa_port *dp = dsa_slave_to_port(dev); 130 u8 tag_dev, tag_port; 131 enum dsa_cmd cmd; 132 u8 *dsa_header; 133 134 if (skb->offload_fwd_mark) { 135 struct dsa_switch_tree *dst = dp->ds->dst; 136 137 cmd = DSA_CMD_FORWARD; 138 139 /* When offloading forwarding for a bridge, inject FORWARD 140 * packets on behalf of a virtual switch device with an index 141 * past the physical switches. 142 */ 143 tag_dev = dst->last_switch + 1 + dp->bridge_num; 144 tag_port = 0; 145 } else { 146 cmd = DSA_CMD_FROM_CPU; 147 tag_dev = dp->ds->index; 148 tag_port = dp->index; 149 } 150 151 if (skb->protocol == htons(ETH_P_8021Q)) { 152 if (extra) { 153 skb_push(skb, extra); 154 dsa_alloc_etype_header(skb, extra); 155 } 156 157 /* Construct tagged DSA tag from 802.1Q tag. */ 158 dsa_header = dsa_etype_header_pos_tx(skb) + extra; 159 dsa_header[0] = (cmd << 6) | 0x20 | tag_dev; 160 dsa_header[1] = tag_port << 3; 161 162 /* Move CFI field from byte 2 to byte 1. */ 163 if (dsa_header[2] & 0x10) { 164 dsa_header[1] |= 0x01; 165 dsa_header[2] &= ~0x10; 166 } 167 } else { 168 struct net_device *br = dp->bridge_dev; 169 u16 vid; 170 171 vid = br ? MV88E6XXX_VID_BRIDGED : MV88E6XXX_VID_STANDALONE; 172 173 skb_push(skb, DSA_HLEN + extra); 174 dsa_alloc_etype_header(skb, DSA_HLEN + extra); 175 176 /* Construct DSA header from untagged frame. */ 177 dsa_header = dsa_etype_header_pos_tx(skb) + extra; 178 179 dsa_header[0] = (cmd << 6) | tag_dev; 180 dsa_header[1] = tag_port << 3; 181 dsa_header[2] = vid >> 8; 182 dsa_header[3] = vid & 0xff; 183 } 184 185 return skb; 186 } 187 188 static struct sk_buff *dsa_rcv_ll(struct sk_buff *skb, struct net_device *dev, 189 u8 extra) 190 { 191 bool trap = false, trunk = false; 192 int source_device, source_port; 193 enum dsa_code code; 194 enum dsa_cmd cmd; 195 u8 *dsa_header; 196 197 /* The ethertype field is part of the DSA header. */ 198 dsa_header = dsa_etype_header_pos_rx(skb); 199 200 cmd = dsa_header[0] >> 6; 201 switch (cmd) { 202 case DSA_CMD_FORWARD: 203 trunk = !!(dsa_header[1] & 4); 204 break; 205 206 case DSA_CMD_TO_CPU: 207 code = (dsa_header[1] & 0x6) | ((dsa_header[2] >> 4) & 1); 208 209 switch (code) { 210 case DSA_CODE_FRAME2REG: 211 /* Remote management is not implemented yet, 212 * drop. 213 */ 214 return NULL; 215 case DSA_CODE_ARP_MIRROR: 216 case DSA_CODE_POLICY_MIRROR: 217 /* Mark mirrored packets to notify any upper 218 * device (like a bridge) that forwarding has 219 * already been done by hardware. 220 */ 221 break; 222 case DSA_CODE_MGMT_TRAP: 223 case DSA_CODE_IGMP_MLD_TRAP: 224 case DSA_CODE_POLICY_TRAP: 225 /* Traps have, by definition, not been 226 * forwarded by hardware, so don't mark them. 227 */ 228 trap = true; 229 break; 230 default: 231 /* Reserved code, this could be anything. Drop 232 * seems like the safest option. 233 */ 234 return NULL; 235 } 236 237 break; 238 239 default: 240 return NULL; 241 } 242 243 source_device = dsa_header[0] & 0x1f; 244 source_port = (dsa_header[1] >> 3) & 0x1f; 245 246 if (trunk) { 247 struct dsa_port *cpu_dp = dev->dsa_ptr; 248 249 /* The exact source port is not available in the tag, 250 * so we inject the frame directly on the upper 251 * team/bond. 252 */ 253 skb->dev = dsa_lag_dev(cpu_dp->dst, source_port); 254 } else { 255 skb->dev = dsa_master_find_slave(dev, source_device, 256 source_port); 257 } 258 259 if (!skb->dev) 260 return NULL; 261 262 /* When using LAG offload, skb->dev is not a DSA slave interface, 263 * so we cannot call dsa_default_offload_fwd_mark and we need to 264 * special-case it. 265 */ 266 if (trunk) 267 skb->offload_fwd_mark = true; 268 else if (!trap) 269 dsa_default_offload_fwd_mark(skb); 270 271 /* If the 'tagged' bit is set; convert the DSA tag to a 802.1Q 272 * tag, and delete the ethertype (extra) if applicable. If the 273 * 'tagged' bit is cleared; delete the DSA tag, and ethertype 274 * if applicable. 275 */ 276 if (dsa_header[0] & 0x20) { 277 u8 new_header[4]; 278 279 /* Insert 802.1Q ethertype and copy the VLAN-related 280 * fields, but clear the bit that will hold CFI (since 281 * DSA uses that bit location for another purpose). 282 */ 283 new_header[0] = (ETH_P_8021Q >> 8) & 0xff; 284 new_header[1] = ETH_P_8021Q & 0xff; 285 new_header[2] = dsa_header[2] & ~0x10; 286 new_header[3] = dsa_header[3]; 287 288 /* Move CFI bit from its place in the DSA header to 289 * its 802.1Q-designated place. 290 */ 291 if (dsa_header[1] & 0x01) 292 new_header[2] |= 0x10; 293 294 /* Update packet checksum if skb is CHECKSUM_COMPLETE. */ 295 if (skb->ip_summed == CHECKSUM_COMPLETE) { 296 __wsum c = skb->csum; 297 c = csum_add(c, csum_partial(new_header + 2, 2, 0)); 298 c = csum_sub(c, csum_partial(dsa_header + 2, 2, 0)); 299 skb->csum = c; 300 } 301 302 memcpy(dsa_header, new_header, DSA_HLEN); 303 304 if (extra) 305 dsa_strip_etype_header(skb, extra); 306 } else { 307 skb_pull_rcsum(skb, DSA_HLEN); 308 dsa_strip_etype_header(skb, DSA_HLEN + extra); 309 } 310 311 return skb; 312 } 313 314 #if IS_ENABLED(CONFIG_NET_DSA_TAG_DSA) 315 316 static struct sk_buff *dsa_xmit(struct sk_buff *skb, struct net_device *dev) 317 { 318 return dsa_xmit_ll(skb, dev, 0); 319 } 320 321 static struct sk_buff *dsa_rcv(struct sk_buff *skb, struct net_device *dev) 322 { 323 if (unlikely(!pskb_may_pull(skb, DSA_HLEN))) 324 return NULL; 325 326 return dsa_rcv_ll(skb, dev, 0); 327 } 328 329 static const struct dsa_device_ops dsa_netdev_ops = { 330 .name = "dsa", 331 .proto = DSA_TAG_PROTO_DSA, 332 .xmit = dsa_xmit, 333 .rcv = dsa_rcv, 334 .needed_headroom = DSA_HLEN, 335 }; 336 337 DSA_TAG_DRIVER(dsa_netdev_ops); 338 MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_DSA); 339 #endif /* CONFIG_NET_DSA_TAG_DSA */ 340 341 #if IS_ENABLED(CONFIG_NET_DSA_TAG_EDSA) 342 343 #define EDSA_HLEN 8 344 345 static struct sk_buff *edsa_xmit(struct sk_buff *skb, struct net_device *dev) 346 { 347 u8 *edsa_header; 348 349 skb = dsa_xmit_ll(skb, dev, EDSA_HLEN - DSA_HLEN); 350 if (!skb) 351 return NULL; 352 353 edsa_header = dsa_etype_header_pos_tx(skb); 354 edsa_header[0] = (ETH_P_EDSA >> 8) & 0xff; 355 edsa_header[1] = ETH_P_EDSA & 0xff; 356 edsa_header[2] = 0x00; 357 edsa_header[3] = 0x00; 358 return skb; 359 } 360 361 static struct sk_buff *edsa_rcv(struct sk_buff *skb, struct net_device *dev) 362 { 363 if (unlikely(!pskb_may_pull(skb, EDSA_HLEN))) 364 return NULL; 365 366 skb_pull_rcsum(skb, EDSA_HLEN - DSA_HLEN); 367 368 return dsa_rcv_ll(skb, dev, EDSA_HLEN - DSA_HLEN); 369 } 370 371 static const struct dsa_device_ops edsa_netdev_ops = { 372 .name = "edsa", 373 .proto = DSA_TAG_PROTO_EDSA, 374 .xmit = edsa_xmit, 375 .rcv = edsa_rcv, 376 .needed_headroom = EDSA_HLEN, 377 }; 378 379 DSA_TAG_DRIVER(edsa_netdev_ops); 380 MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_EDSA); 381 #endif /* CONFIG_NET_DSA_TAG_EDSA */ 382 383 static struct dsa_tag_driver *dsa_tag_drivers[] = { 384 #if IS_ENABLED(CONFIG_NET_DSA_TAG_DSA) 385 &DSA_TAG_DRIVER_NAME(dsa_netdev_ops), 386 #endif 387 #if IS_ENABLED(CONFIG_NET_DSA_TAG_EDSA) 388 &DSA_TAG_DRIVER_NAME(edsa_netdev_ops), 389 #endif 390 }; 391 392 module_dsa_tag_drivers(dsa_tag_drivers); 393 394 MODULE_LICENSE("GPL"); 395