linux-stable/net/dsa/tag_mtk.c
John Crispin 2dd592b274 net-next: tag_mtk: add flow_dissect callback to the ops struct
The MT7530 inserts the 4 magic header in between the 802.3 address and
protocol field. The patch implements the callback that can be called by
the flow dissector to figure out the real protocol and offset of the
network header. With this patch applied we can properly parse the packet
and thus make hashing function properly.

Signed-off-by: Muciri Gatimu <muciri@openmesh.com>
Signed-off-by: Shashidhar Lakkavalli <shashidhar.lakkavalli@openmesh.com>
Signed-off-by: John Crispin <john@phrozen.org>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-08-09 22:51:47 -07:00

103 lines
2.6 KiB
C

/*
* Mediatek DSA Tag support
* Copyright (C) 2017 Landen Chao <landen.chao@mediatek.com>
* Sean Wang <sean.wang@mediatek.com>
* 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_slave_priv *p = netdev_priv(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 << p->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,
struct net_device *orig_dev)
{
struct dsa_switch_tree *dst = dev->dsa_ptr;
struct dsa_switch *ds;
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);
/* This protocol doesn't support cascading multiple
* switches so it's safe to assume the switch is first
* in the tree.
*/
ds = dst->ds[0];
if (!ds)
return NULL;
/* Get source port information */
port = (hdr & MTK_HDR_RECV_SOURCE_PORT_MASK);
if (!ds->ports[port].netdev)
return NULL;
skb->dev = ds->ports[port].netdev;
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,
};