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