[linux-block.git] / net / dsa / tag_dsa.c

// 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/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 *dsa_header;

	if (skb->protocol == htons(ETH_P_8021Q)) {
		if (extra) {
			skb_push(skb, extra);
			memmove(skb->data, skb->data + extra, 2 * ETH_ALEN);
		}

		/* Construct tagged FROM_CPU DSA tag from 802.1Q tag. */
		dsa_header = skb->data + 2 * ETH_ALEN + extra;
		dsa_header[0] = (DSA_CMD_FROM_CPU << 6) | 0x20 | dp->ds->index;
		dsa_header[1] = dp->index << 3;

		/* Move CFI field from byte 2 to byte 1. */
		if (dsa_header[2] & 0x10) {
			dsa_header[1] |= 0x01;
			dsa_header[2] &= ~0x10;
		}
	} else {
		skb_push(skb, DSA_HLEN + extra);
		memmove(skb->data, skb->data + DSA_HLEN + extra, 2 * ETH_ALEN);

		/* Construct untagged FROM_CPU DSA tag. */
		dsa_header = skb->data + 2 * ETH_ALEN + extra;
		dsa_header[0] = (DSA_CMD_FROM_CPU << 6) | dp->ds->index;
		dsa_header[1] = dp->index << 3;
		dsa_header[2] = 0x00;
		dsa_header[3] = 0x00;
	}

	return skb;
}

static struct sk_buff *dsa_rcv_ll(struct sk_buff *skb, struct net_device *dev,
				  u8 extra)
{
	int source_device, source_port;
	bool trunk = false;
	enum dsa_code code;
	enum dsa_cmd cmd;
	u8 *dsa_header;

	/* The ethertype field is part of the DSA header. */
	dsa_header = skb->data - 2;

	cmd = dsa_header[0] >> 6;
	switch (cmd) {
	case DSA_CMD_FORWARD:
		skb->offload_fwd_mark = 1;

		trunk = !!(dsa_header[1] & 7);
		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.
			 */
			skb->offload_fwd_mark = 1;
			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.
			 */
			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;

	/* 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)
			memmove(skb->data - ETH_HLEN,
				skb->data - ETH_HLEN - extra,
				2 * ETH_ALEN);
	} else {
		skb_pull_rcsum(skb, DSA_HLEN);
		memmove(skb->data - ETH_HLEN,
			skb->data - ETH_HLEN - DSA_HLEN - extra,
			2 * ETH_ALEN);
	}

	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,
			       struct packet_type *pt)
{
	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,
	.overhead = 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 = skb->data + 2 * ETH_ALEN;
	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,
				struct packet_type *pt)
{
	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,
	.overhead = 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");
Commit	Line	Data
dfedd3b6	1	// SPDX-License-Identifier: GPL-2.0+
cf85d08f	2	/*
469ee5fe	3	* Regular and Ethertype DSA tagging
e84665c9	4	* Copyright (c) 2008-2009 Marvell Semiconductor
469ee5fe TW	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
cf85d08f LB	46	*/
	47
	48	#include <linux/etherdevice.h>
	49	#include <linux/list.h>
5a0e3ad6	50	#include <linux/slab.h>
ea5dd34b	51
cf85d08f LB	52	#include "dsa_priv.h"
	53
	54	#define DSA_HLEN 4
	55
469ee5fe TW	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	};
e468d141	88
469ee5fe TW	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	};
e468d141	124
469ee5fe TW	125	static struct sk_buff dsa_xmit_ll(struct sk_buff skb, struct net_device *dev,
469ee5fe TW	126	u8 extra)
cf85d08f	127	{
d945097b	128	struct dsa_port *dp = dsa_slave_to_port(dev);
cf85d08f LB	129	u8 *dsa_header;
cf85d08f LB	130
cf85d08f	131	if (skb->protocol == htons(ETH_P_8021Q)) {
469ee5fe TW	132	if (extra) {
	133	skb_push(skb, extra);
	134	memmove(skb->data, skb->data + extra, 2 * ETH_ALEN);
	135	}
	136
13f49b6f	137	/* Construct tagged FROM_CPU DSA tag from 802.1Q tag. */
469ee5fe TW	138	dsa_header = skb->data + 2 * ETH_ALEN + extra;
469ee5fe TW	139	dsa_header[0] = (DSA_CMD_FROM_CPU << 6) \| 0x20 \| dp->ds->index;
d945097b	140	dsa_header[1] = dp->index << 3;
cf85d08f	141
13f49b6f	142	/* Move CFI field from byte 2 to byte 1. */
cf85d08f LB	143	if (dsa_header[2] & 0x10) {
	144	dsa_header[1] \|= 0x01;
	145	dsa_header[2] &= ~0x10;
	146	}
	147	} else {
469ee5fe TW	148	skb_push(skb, DSA_HLEN + extra);
469ee5fe TW	149	memmove(skb->data, skb->data + DSA_HLEN + extra, 2 * ETH_ALEN);
cf85d08f	150
13f49b6f	151	/* Construct untagged FROM_CPU DSA tag. */
469ee5fe TW	152	dsa_header = skb->data + 2 * ETH_ALEN + extra;
469ee5fe TW	153	dsa_header[0] = (DSA_CMD_FROM_CPU << 6) \| dp->ds->index;
d945097b	154	dsa_header[1] = dp->index << 3;
cf85d08f LB	155	dsa_header[2] = 0x00;
	156	dsa_header[3] = 0x00;
	157	}
	158
4ed70ce9	159	return skb;
cf85d08f LB	160	}
cf85d08f LB	161
469ee5fe TW	162	static struct sk_buff dsa_rcv_ll(struct sk_buff skb, struct net_device *dev,
469ee5fe TW	163	u8 extra)
cf85d08f	164	{
469ee5fe	165	int source_device, source_port;
5b60dadb	166	bool trunk = false;
469ee5fe TW	167	enum dsa_code code;
469ee5fe TW	168	enum dsa_cmd cmd;
cf85d08f	169	u8 *dsa_header;
cf85d08f	170
13f49b6f	171	/* The ethertype field is part of the DSA header. */
cf85d08f LB	172	dsa_header = skb->data - 2;
cf85d08f LB	173
469ee5fe TW	174	cmd = dsa_header[0] >> 6;
	175	switch (cmd) {
	176	case DSA_CMD_FORWARD:
	177	skb->offload_fwd_mark = 1;
5b60dadb TW	178
5b60dadb TW	179	trunk = !!(dsa_header[1] & 7);
469ee5fe	180	break;
e468d141	181
469ee5fe	182	case DSA_CMD_TO_CPU:
e468d141 TW	183	code = (dsa_header[1] & 0x6) \| ((dsa_header[2] >> 4) & 1);
e468d141 TW	184
469ee5fe TW	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	*/
e468d141	197	skb->offload_fwd_mark = 1;
469ee5fe TW	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	}
e468d141 TW	212
	213	break;
	214
e468d141	215	default:
54709795	216	return NULL;
e468d141	217	}
cf85d08f	218
e84665c9	219	source_device = dsa_header[0] & 0x1f;
cf85d08f	220	source_port = (dsa_header[1] >> 3) & 0x1f;
e84665c9	221
5b60dadb TW	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
3775b1b7	235	if (!skb->dev)
54709795	236	return NULL;
cf85d08f	237
469ee5fe TW	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.
cf85d08f LB	242	*/
	243	if (dsa_header[0] & 0x20) {
	244	u8 new_header[4];
	245
13f49b6f	246	/* Insert 802.1Q ethertype and copy the VLAN-related
cf85d08f LB	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
13f49b6f TW	255	/* Move CFI bit from its place in the DSA header to
13f49b6f TW	256	* its 802.1Q-designated place.
cf85d08f LB	257	*/
	258	if (dsa_header[1] & 0x01)
	259	new_header[2] \|= 0x10;
	260
13f49b6f	261	/* Update packet checksum if skb is CHECKSUM_COMPLETE. */
cf85d08f LB	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);
469ee5fe TW	270
	271	if (extra)
	272	memmove(skb->data - ETH_HLEN,
	273	skb->data - ETH_HLEN - extra,
	274	2 * ETH_ALEN);
cf85d08f	275	} else {
cf85d08f LB	276	skb_pull_rcsum(skb, DSA_HLEN);
cf85d08f LB	277	memmove(skb->data - ETH_HLEN,
469ee5fe	278	skb->data - ETH_HLEN - DSA_HLEN - extra,
cf85d08f LB	279	2 * ETH_ALEN);
	280	}
	281
a86d8bec	282	return skb;
cf85d08f LB	283	}
cf85d08f LB	284
469ee5fe TW	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
f81a43e8	301	static const struct dsa_device_ops dsa_netdev_ops = {
469ee5fe TW	302	.name = "dsa",
	303	.proto = DSA_TAG_PROTO_DSA,
	304	.xmit = dsa_xmit,
	305	.rcv = dsa_rcv,
a5dd3087	306	.overhead = DSA_HLEN,
cf85d08f	307	};
0b42f033	308
469ee5fe	309	DSA_TAG_DRIVER(dsa_netdev_ops);
0b42f033	310	MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_DSA);
469ee5fe TW	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;
d3b8c049	324
469ee5fe TW	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");