93 lines
2.3 KiB
C
93 lines
2.3 KiB
C
/*
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* Mediatek DSA Tag support
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* Copyright (C) 2017 Landen Chao <landen.chao@mediatek.com>
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* Sean Wang <sean.wang@mediatek.com>
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 and
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* only version 2 as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*/
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#include <linux/etherdevice.h>
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#include "dsa_priv.h"
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#define MTK_HDR_LEN 4
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#define MTK_HDR_RECV_SOURCE_PORT_MASK GENMASK(2, 0)
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#define MTK_HDR_XMIT_DP_BIT_MASK GENMASK(5, 0)
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static struct sk_buff *mtk_tag_xmit(struct sk_buff *skb,
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struct net_device *dev)
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{
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struct dsa_port *dp = dsa_slave_to_port(dev);
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u8 *mtk_tag;
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if (skb_cow_head(skb, MTK_HDR_LEN) < 0)
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return NULL;
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skb_push(skb, MTK_HDR_LEN);
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memmove(skb->data, skb->data + MTK_HDR_LEN, 2 * ETH_ALEN);
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/* Build the tag after the MAC Source Address */
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mtk_tag = skb->data + 2 * ETH_ALEN;
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mtk_tag[0] = 0;
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mtk_tag[1] = (1 << dp->index) & MTK_HDR_XMIT_DP_BIT_MASK;
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mtk_tag[2] = 0;
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mtk_tag[3] = 0;
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return skb;
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}
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static struct sk_buff *mtk_tag_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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int port;
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__be16 *phdr, hdr;
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if (unlikely(!pskb_may_pull(skb, MTK_HDR_LEN)))
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return NULL;
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/* The MTK header is added by the switch between src addr
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* and ethertype at this point, skb->data points to 2 bytes
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* after src addr so header should be 2 bytes right before.
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*/
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phdr = (__be16 *)(skb->data - 2);
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hdr = ntohs(*phdr);
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/* Remove MTK tag and recalculate checksum. */
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skb_pull_rcsum(skb, MTK_HDR_LEN);
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memmove(skb->data - ETH_HLEN,
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skb->data - ETH_HLEN - MTK_HDR_LEN,
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2 * ETH_ALEN);
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/* Get source port information */
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port = (hdr & MTK_HDR_RECV_SOURCE_PORT_MASK);
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skb->dev = dsa_master_find_slave(dev, 0, port);
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if (!skb->dev)
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return NULL;
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return skb;
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}
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static int mtk_tag_flow_dissect(const struct sk_buff *skb, __be16 *proto,
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int *offset)
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{
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*offset = 4;
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*proto = ((__be16 *)skb->data)[1];
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return 0;
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}
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const struct dsa_device_ops mtk_netdev_ops = {
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.xmit = mtk_tag_xmit,
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.rcv = mtk_tag_rcv,
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.flow_dissect = mtk_tag_flow_dissect,
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};
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