[linux.git] / net / dsa / tag_mtk.c

/*
 * Mediatek DSA Tag support
 * Copyright (C) 2017 Landen Chao <[email protected]>
 *		      Sean Wang <[email protected]>
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 and
 * only version 2 as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 */

#include <linux/etherdevice.h>

#include "dsa_priv.h"

#define MTK_HDR_LEN		4
#define MTK_HDR_RECV_SOURCE_PORT_MASK	GENMASK(2, 0)
#define MTK_HDR_XMIT_DP_BIT_MASK	GENMASK(5, 0)

static struct sk_buff *mtk_tag_xmit(struct sk_buff *skb,
				    struct net_device *dev)
{
	struct dsa_port *dp = dsa_slave_to_port(dev);
	u8 *mtk_tag;

	if (skb_cow_head(skb, MTK_HDR_LEN) < 0)
		return NULL;

	skb_push(skb, MTK_HDR_LEN);

	memmove(skb->data, skb->data + MTK_HDR_LEN, 2 * ETH_ALEN);

	/* Build the tag after the MAC Source Address */
	mtk_tag = skb->data + 2 * ETH_ALEN;
	mtk_tag[0] = 0;
	mtk_tag[1] = (1 << dp->index) & MTK_HDR_XMIT_DP_BIT_MASK;
	mtk_tag[2] = 0;
	mtk_tag[3] = 0;

	return skb;
}

static struct sk_buff *mtk_tag_rcv(struct sk_buff *skb, struct net_device *dev,
				   struct packet_type *pt)
{
	int port;
	__be16 *phdr, hdr;

	if (unlikely(!pskb_may_pull(skb, MTK_HDR_LEN)))
		return NULL;

	/* The MTK header is added by the switch between src addr
	 * and ethertype at this point, skb->data points to 2 bytes
	 * after src addr so header should be 2 bytes right before.
	 */
	phdr = (__be16 *)(skb->data - 2);
	hdr = ntohs(*phdr);

	/* Remove MTK tag and recalculate checksum. */
	skb_pull_rcsum(skb, MTK_HDR_LEN);

	memmove(skb->data - ETH_HLEN,
		skb->data - ETH_HLEN - MTK_HDR_LEN,
		2 * ETH_ALEN);

	/* Get source port information */
	port = (hdr & MTK_HDR_RECV_SOURCE_PORT_MASK);

	skb->dev = dsa_master_find_slave(dev, 0, port);
	if (!skb->dev)
		return NULL;

	return skb;
}

static int mtk_tag_flow_dissect(const struct sk_buff *skb, __be16 *proto,
				int *offset)
{
	*offset = 4;
	*proto = ((__be16 *)skb->data)[1];

	return 0;
}

const struct dsa_device_ops mtk_netdev_ops = {
	.xmit		= mtk_tag_xmit,
	.rcv		= mtk_tag_rcv,
	.flow_dissect	= mtk_tag_flow_dissect,
};
Commit	Line	Data
5cd8985a SW	1	/*
	2	* Mediatek DSA Tag support
	3	* Copyright (C) 2017 Landen Chao <[email protected]>
	4	* Sean Wang <[email protected]>
	5	* This program is free software; you can redistribute it and/or modify
	6	* it under the terms of the GNU General Public License version 2 and
	7	* only version 2 as published by the Free Software Foundation.
	8	*
	9	* This program is distributed in the hope that it will be useful,
	10	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	11	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	12	* GNU General Public License for more details.
	13	*/
	14
	15	#include <linux/etherdevice.h>
ea5dd34b	16
5cd8985a SW	17	#include "dsa_priv.h"
	18
	19	#define MTK_HDR_LEN 4
	20	#define MTK_HDR_RECV_SOURCE_PORT_MASK GENMASK(2, 0)
	21	#define MTK_HDR_XMIT_DP_BIT_MASK GENMASK(5, 0)
	22
	23	static struct sk_buff mtk_tag_xmit(struct sk_buff skb,
	24	struct net_device *dev)
	25	{
d945097b	26	struct dsa_port *dp = dsa_slave_to_port(dev);
5cd8985a SW	27	u8 *mtk_tag;
	28
	29	if (skb_cow_head(skb, MTK_HDR_LEN) < 0)
fe47d563	30	return NULL;
5cd8985a SW	31
	32	skb_push(skb, MTK_HDR_LEN);
	33
	34	memmove(skb->data, skb->data + MTK_HDR_LEN, 2 * ETH_ALEN);
	35
	36	/* Build the tag after the MAC Source Address */
	37	mtk_tag = skb->data + 2 * ETH_ALEN;
	38	mtk_tag[0] = 0;
d945097b	39	mtk_tag[1] = (1 << dp->index) & MTK_HDR_XMIT_DP_BIT_MASK;
5cd8985a SW	40	mtk_tag[2] = 0;
	41	mtk_tag[3] = 0;
	42
	43	return skb;
5cd8985a SW	44	}
5cd8985a SW	45
a86d8bec	46	static struct sk_buff mtk_tag_rcv(struct sk_buff skb, struct net_device *dev,
89e49506	47	struct packet_type *pt)
5cd8985a	48	{
5cd8985a SW	49	int port;
	50	__be16 *phdr, hdr;
	51
5cd8985a	52	if (unlikely(!pskb_may_pull(skb, MTK_HDR_LEN)))
54709795	53	return NULL;
5cd8985a SW	54
	55	/* The MTK header is added by the switch between src addr
	56	* and ethertype at this point, skb->data points to 2 bytes
	57	* after src addr so header should be 2 bytes right before.
	58	*/
	59	phdr = (__be16 *)(skb->data - 2);
	60	hdr = ntohs(*phdr);
	61
	62	/* Remove MTK tag and recalculate checksum. */
	63	skb_pull_rcsum(skb, MTK_HDR_LEN);
	64
	65	memmove(skb->data - ETH_HLEN,
	66	skb->data - ETH_HLEN - MTK_HDR_LEN,
	67	2 * ETH_ALEN);
	68
5cd8985a SW	69	/* Get source port information */
5cd8985a SW	70	port = (hdr & MTK_HDR_RECV_SOURCE_PORT_MASK);
5cd8985a	71
2231c43b	72	skb->dev = dsa_master_find_slave(dev, 0, port);
3775b1b7 VD	73	if (!skb->dev)
3775b1b7 VD	74	return NULL;
5cd8985a	75
a86d8bec	76	return skb;
5cd8985a SW	77	}
5cd8985a SW	78
2dd592b2 JC	79	static int mtk_tag_flow_dissect(const struct sk_buff skb, __be16 proto,
	80	int *offset)
	81	{
	82	*offset = 4;
	83	proto = ((__be16 )skb->data)[1];
	84
	85	return 0;
	86	}
	87
5cd8985a	88	const struct dsa_device_ops mtk_netdev_ops = {
2dd592b2 JC	89	.xmit = mtk_tag_xmit,
	90	.rcv = mtk_tag_rcv,
	91	.flow_dissect = mtk_tag_flow_dissect,
5cd8985a	92	};