// SPDX-License-Identifier: GPL-2.0+ /* * Regular and Ethertype DSA tagging * Copyright (c) 2008-2009 Marvell Semiconductor * * Regular DSA * ----------- * For untagged (in 802.1Q terms) packets, the switch will splice in * the tag between the SA and the ethertype of the original * packet. Tagged frames will instead have their outermost .1Q tag * converted to a DSA tag. It expects the same layout when receiving * packets from the CPU. * * Example: * * .----.----.----.--------- * Pu: | DA | SA | ET | Payload ... * '----'----'----'--------- * 6 6 2 N * .----.----.--------.-----.----.--------- * Pt: | DA | SA | 0x8100 | TCI | ET | Payload ... * '----'----'--------'-----'----'--------- * 6 6 2 2 2 N * .----.----.-----.----.--------- * Pd: | DA | SA | DSA | ET | Payload ... * '----'----'-----'----'--------- * 6 6 4 2 N * * No matter if a packet is received untagged (Pu) or tagged (Pt), * they will both have the same layout (Pd) when they are sent to the * CPU. This is done by ignoring 802.3, replacing the ethertype field * with more metadata, among which is a bit to signal if the original * packet was tagged or not. * * Ethertype DSA * ------------- * Uses the exact same tag format as regular DSA, but also includes a * proper ethertype field (which the mv88e6xxx driver sets to * ETH_P_EDSA/0xdada) followed by two zero bytes: * * .----.----.--------.--------.-----.----.--------- * | DA | SA | 0xdada | 0x0000 | DSA | ET | Payload ... * '----'----'--------'--------'-----'----'--------- * 6 6 2 2 4 2 N */ #include <linux/dsa/mv88e6xxx.h> #include <linux/etherdevice.h> #include <linux/list.h> #include <linux/slab.h> #include "tag.h" #define DSA_NAME "dsa" #define EDSA_NAME "edsa" #define DSA_HLEN 4 /** * enum dsa_cmd - DSA Command * @DSA_CMD_TO_CPU: Set on packets that were trapped or mirrored to * the CPU port. This is needed to implement control protocols, * e.g. STP and LLDP, that must not allow those control packets to * be switched according to the normal rules. * @DSA_CMD_FROM_CPU: Used by the CPU to send a packet to a specific * port, ignoring all the barriers that the switch normally * enforces (VLANs, STP port states etc.). No source address * learning takes place. "sudo send packet" * @DSA_CMD_TO_SNIFFER: Set on the copies of packets that matched some * user configured ingress or egress monitor criteria. These are * forwarded by the switch tree to the user configured ingress or * egress monitor port, which can be set to the CPU port or a * regular port. If the destination is a regular port, the tag * will be removed before egressing the port. If the destination * is the CPU port, the tag will not be removed. * @DSA_CMD_FORWARD: This tag is used on all bulk traffic passing * through the switch tree, including the flows that are directed * towards the CPU. Its device/port tuple encodes the original * source port on which the packet ingressed. It can also be used * on transmit by the CPU to defer the forwarding decision to the * hardware, based on the current config of PVT/VTU/ATU * etc. Source address learning takes places if enabled on the * receiving DSA/CPU port. */ enum dsa_cmd { DSA_CMD_TO_CPU = 0, DSA_CMD_FROM_CPU = 1, DSA_CMD_TO_SNIFFER = 2, DSA_CMD_FORWARD = 3 }; /** * enum dsa_code - TO_CPU Code * * @DSA_CODE_MGMT_TRAP: DA was classified as a management * address. Typical examples include STP BPDUs and LLDP. * @DSA_CODE_FRAME2REG: Response to a "remote management" request. * @DSA_CODE_IGMP_MLD_TRAP: IGMP/MLD signaling. * @DSA_CODE_POLICY_TRAP: Frame matched some policy configuration on * the device. Typical examples are matching on DA/SA/VID and DHCP * snooping. * @DSA_CODE_ARP_MIRROR: The name says it all really. * @DSA_CODE_POLICY_MIRROR: Same as @DSA_CODE_POLICY_TRAP, but the * particular policy was set to trigger a mirror instead of a * trap. * @DSA_CODE_RESERVED_6: Unused on all devices up to at least 6393X. * @DSA_CODE_RESERVED_7: Unused on all devices up to at least 6393X. * * A 3-bit code is used to relay why a particular frame was sent to * the CPU. We only use this to determine if the packet was mirrored * or trapped, i.e. whether the packet has been forwarded by hardware * or not. * * This is the superset of all possible codes. Any particular device * may only implement a subset. */ enum dsa_code { DSA_CODE_MGMT_TRAP = 0, DSA_CODE_FRAME2REG = 1, DSA_CODE_IGMP_MLD_TRAP = 2, DSA_CODE_POLICY_TRAP = 3, DSA_CODE_ARP_MIRROR = 4, DSA_CODE_POLICY_MIRROR = 5, DSA_CODE_RESERVED_6 = 6, DSA_CODE_RESERVED_7 = 7 }; static struct sk_buff *dsa_xmit_ll(struct sk_buff *skb, struct net_device *dev, u8 extra) { struct dsa_port *dp = dsa_user_to_port(dev); struct net_device *br_dev; u8 tag_dev, tag_port; enum dsa_cmd cmd; u8 *dsa_header; if (skb->offload_fwd_mark) { unsigned int bridge_num = dsa_port_bridge_num_get(dp); struct dsa_switch_tree *dst = dp->ds->dst; cmd = DSA_CMD_FORWARD; /* When offloading forwarding for a bridge, inject FORWARD * packets on behalf of a virtual switch device with an index * past the physical switches. */ tag_dev = dst->last_switch + bridge_num; tag_port = 0; } else { cmd = DSA_CMD_FROM_CPU; tag_dev = dp->ds->index; tag_port = dp->index; } br_dev = dsa_port_bridge_dev_get(dp); /* If frame is already 802.1Q tagged, we can convert it to a DSA * tag (avoiding a memmove), but only if the port is standalone * (in which case we always send FROM_CPU) or if the port's * bridge has VLAN filtering enabled (in which case the CPU port * will be a member of the VLAN). */ if (skb->protocol == htons(ETH_P_8021Q) && (!br_dev || br_vlan_enabled(br_dev))) { if (extra) { skb_push(skb, extra); dsa_alloc_etype_header(skb, extra); } /* Construct tagged DSA tag from 802.1Q tag. */ dsa_header = dsa_etype_header_pos_tx(skb) + extra; dsa_header[0] = (cmd << 6) | 0x20 | tag_dev; dsa_header[1] = tag_port << 3; /* Move CFI field from byte 2 to byte 1. */ if (dsa_header[2] & 0x10) { dsa_header[1] |= 0x01; dsa_header[2] &= ~0x10; } } else { u16 vid; vid = br_dev ? MV88E6XXX_VID_BRIDGED : MV88E6XXX_VID_STANDALONE; skb_push(skb, DSA_HLEN + extra); dsa_alloc_etype_header(skb, DSA_HLEN + extra); /* Construct DSA header from untagged frame. */ dsa_header = dsa_etype_header_pos_tx(skb) + extra; dsa_header[0] = (cmd << 6) | tag_dev; dsa_header[1] = tag_port << 3; dsa_header[2] = vid >> 8; dsa_header[3] = vid & 0xff; } return skb; } static struct sk_buff *dsa_rcv_ll(struct sk_buff *skb, struct net_device *dev, u8 extra) { bool trap = false, trunk = false; int source_device, source_port; enum dsa_code code; enum dsa_cmd cmd; u8 *dsa_header; /* The ethertype field is part of the DSA header. */ dsa_header = dsa_etype_header_pos_rx(skb); cmd = dsa_header[0] >> 6; switch (cmd) { case DSA_CMD_FORWARD: trunk = !!(dsa_header[1] & 4); break; case DSA_CMD_TO_CPU: code = (dsa_header[1] & 0x6) | ((dsa_header[2] >> 4) & 1); switch (code) { case DSA_CODE_FRAME2REG: /* Remote management is not implemented yet, * drop. */ return NULL; case DSA_CODE_ARP_MIRROR: case DSA_CODE_POLICY_MIRROR: /* Mark mirrored packets to notify any upper * device (like a bridge) that forwarding has * already been done by hardware. */ break; case DSA_CODE_MGMT_TRAP: case DSA_CODE_IGMP_MLD_TRAP: case DSA_CODE_POLICY_TRAP: /* Traps have, by definition, not been * forwarded by hardware, so don't mark them. */ trap = true; break; default: /* Reserved code, this could be anything. Drop * seems like the safest option. */ return NULL; } break; default: return NULL; } source_device = dsa_header[0] & 0x1f; source_port = (dsa_header[1] >> 3) & 0x1f; if (trunk) { struct dsa_port *cpu_dp = dev->dsa_ptr; struct dsa_lag *lag; /* The exact source port is not available in the tag, * so we inject the frame directly on the upper * team/bond. */ lag = dsa_lag_by_id(cpu_dp->dst, source_port + 1); skb->dev = lag ? lag->dev : NULL; } else { skb->dev = dsa_conduit_find_user(dev, source_device, source_port); } if (!skb->dev) return NULL; /* When using LAG offload, skb->dev is not a DSA user interface, * so we cannot call dsa_default_offload_fwd_mark and we need to * special-case it. */ if (trunk) skb->offload_fwd_mark = true; else if (!trap) dsa_default_offload_fwd_mark(skb); /* If the 'tagged' bit is set; convert the DSA tag to a 802.1Q * tag, and delete the ethertype (extra) if applicable. If the * 'tagged' bit is cleared; delete the DSA tag, and ethertype * if applicable. */ if (dsa_header[0] & 0x20) { u8 new_header[4]; /* Insert 802.1Q ethertype and copy the VLAN-related * fields, but clear the bit that will hold CFI (since * DSA uses that bit location for another purpose). */ new_header[0] = (ETH_P_8021Q >> 8) & 0xff; new_header[1] = ETH_P_8021Q & 0xff; new_header[2] = dsa_header[2] & ~0x10; new_header[3] = dsa_header[3]; /* Move CFI bit from its place in the DSA header to * its 802.1Q-designated place. */ if (dsa_header[1] & 0x01) new_header[2] |= 0x10; /* Update packet checksum if skb is CHECKSUM_COMPLETE. */ if (skb->ip_summed == CHECKSUM_COMPLETE) { __wsum c = skb->csum; c = csum_add(c, csum_partial(new_header + 2, 2, 0)); c = csum_sub(c, csum_partial(dsa_header + 2, 2, 0)); skb->csum = c; } memcpy(dsa_header, new_header, DSA_HLEN); if (extra) dsa_strip_etype_header(skb, extra); } else { skb_pull_rcsum(skb, DSA_HLEN); dsa_strip_etype_header(skb, DSA_HLEN + extra); } return skb; } #if IS_ENABLED(CONFIG_NET_DSA_TAG_DSA) static struct sk_buff *dsa_xmit(struct sk_buff *skb, struct net_device *dev) { return dsa_xmit_ll(skb, dev, 0); } static struct sk_buff *dsa_rcv(struct sk_buff *skb, struct net_device *dev) { if (unlikely(!pskb_may_pull(skb, DSA_HLEN))) return NULL; return dsa_rcv_ll(skb, dev, 0); } static const struct dsa_device_ops dsa_netdev_ops = { .name = DSA_NAME, .proto = DSA_TAG_PROTO_DSA, .xmit = dsa_xmit, .rcv = dsa_rcv, .needed_headroom = DSA_HLEN, }; DSA_TAG_DRIVER(dsa_netdev_ops); MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_DSA, DSA_NAME); #endif /* CONFIG_NET_DSA_TAG_DSA */ #if IS_ENABLED(CONFIG_NET_DSA_TAG_EDSA) #define EDSA_HLEN 8 static struct sk_buff *edsa_xmit(struct sk_buff *skb, struct net_device *dev) { u8 *edsa_header; skb = dsa_xmit_ll(skb, dev, EDSA_HLEN - DSA_HLEN); if (!skb) return NULL; edsa_header = dsa_etype_header_pos_tx(skb); edsa_header[0] = (ETH_P_EDSA >> 8) & 0xff; edsa_header[1] = ETH_P_EDSA & 0xff; edsa_header[2] = 0x00; edsa_header[3] = 0x00; return skb; } static struct sk_buff *edsa_rcv(struct sk_buff *skb, struct net_device *dev) { if (unlikely(!pskb_may_pull(skb, EDSA_HLEN))) return NULL; skb_pull_rcsum(skb, EDSA_HLEN - DSA_HLEN); return dsa_rcv_ll(skb, dev, EDSA_HLEN - DSA_HLEN); } static const struct dsa_device_ops edsa_netdev_ops = { .name = EDSA_NAME, .proto = DSA_TAG_PROTO_EDSA, .xmit = edsa_xmit, .rcv = edsa_rcv, .needed_headroom = EDSA_HLEN, }; DSA_TAG_DRIVER(edsa_netdev_ops); MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_EDSA, EDSA_NAME); #endif /* CONFIG_NET_DSA_TAG_EDSA */ static struct dsa_tag_driver *dsa_tag_drivers[] = { #if IS_ENABLED(CONFIG_NET_DSA_TAG_DSA) &DSA_TAG_DRIVER_NAME(dsa_netdev_ops), #endif #if IS_ENABLED(CONFIG_NET_DSA_TAG_EDSA) &DSA_TAG_DRIVER_NAME(edsa_netdev_ops), #endif }; module_dsa_tag_drivers(dsa_tag_drivers); MODULE_DESCRIPTION("DSA tag driver for Marvell switches using DSA headers"); MODULE_LICENSE("GPL");
