| // 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 "dsa_priv.h" |
| |
| #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_slave_to_port(dev); |
| u8 tag_dev, tag_port; |
| enum dsa_cmd cmd; |
| u8 *dsa_header; |
| |
| if (skb->offload_fwd_mark) { |
| 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 + 1 + dp->bridge_num; |
| tag_port = 0; |
| } else { |
| cmd = DSA_CMD_FROM_CPU; |
| tag_dev = dp->ds->index; |
| tag_port = dp->index; |
| } |
| |
| if (skb->protocol == htons(ETH_P_8021Q)) { |
| 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 { |
| struct net_device *br = dp->bridge_dev; |
| u16 vid; |
| |
| vid = br ? 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; |
| |
| /* The exact source port is not available in the tag, |
| * so we inject the frame directly on the upper |
| * team/bond. |
| */ |
| skb->dev = dsa_lag_dev(cpu_dp->dst, source_port); |
| } else { |
| skb->dev = dsa_master_find_slave(dev, source_device, |
| source_port); |
| } |
| |
| if (!skb->dev) |
| return NULL; |
| |
| /* When using LAG offload, skb->dev is not a DSA slave 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", |
| .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); |
| #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", |
| .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); |
| #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_LICENSE("GPL"); |