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