LXR linux/net/dsa/tag

   1/*
   2 * Copyright (c) 2015, The Linux Foundation. All rights reserved.
   3 *
   4 * This program is free software; you can redistribute it and/or modify
   5 * it under the terms of the GNU General Public License version 2 and
   6 * only version 2 as published by the Free Software Foundation.
   7 *
   8 * This program is distributed in the hope that it will be useful,
   9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11 * GNU General Public License for more details.
  12 */
  13
  14#include <linux/etherdevice.h>
  15
  16#include "dsa_priv.h"
  17
  18#define QCA_HDR_LEN     2
  19#define QCA_HDR_VERSION 0x2
  20
  21#define QCA_HDR_RECV_VERSION_MASK       GENMASK(15, 14)
  22#define QCA_HDR_RECV_VERSION_S          14
  23#define QCA_HDR_RECV_PRIORITY_MASK      GENMASK(13, 11)
  24#define QCA_HDR_RECV_PRIORITY_S         11
  25#define QCA_HDR_RECV_TYPE_MASK          GENMASK(10, 6)
  26#define QCA_HDR_RECV_TYPE_S             6
  27#define QCA_HDR_RECV_FRAME_IS_TAGGED    BIT(3)
  28#define QCA_HDR_RECV_SOURCE_PORT_MASK   GENMASK(2, 0)
  29
  30#define QCA_HDR_XMIT_VERSION_MASK       GENMASK(15, 14)
  31#define QCA_HDR_XMIT_VERSION_S          14
  32#define QCA_HDR_XMIT_PRIORITY_MASK      GENMASK(13, 11)
  33#define QCA_HDR_XMIT_PRIORITY_S         11
  34#define QCA_HDR_XMIT_CONTROL_MASK       GENMASK(10, 8)
  35#define QCA_HDR_XMIT_CONTROL_S          8
  36#define QCA_HDR_XMIT_FROM_CPU           BIT(7)
  37#define QCA_HDR_XMIT_DP_BIT_MASK        GENMASK(6, 0)
  38
  39static struct sk_buff *qca_tag_xmit(struct sk_buff *skb, struct net_device *dev)
  40{
  41        struct dsa_port *dp = dsa_slave_to_port(dev);
  42        u16 *phdr, hdr;
  43
  44        dev->stats.tx_packets++;
  45        dev->stats.tx_bytes += skb->len;
  46
  47        if (skb_cow_head(skb, 0) < 0)
  48                return NULL;
  49
  50        skb_push(skb, QCA_HDR_LEN);
  51
  52        memmove(skb->data, skb->data + QCA_HDR_LEN, 2 * ETH_ALEN);
  53        phdr = (u16 *)(skb->data + 2 * ETH_ALEN);
  54
  55        /* Set the version field, and set destination port information */
  56        hdr = QCA_HDR_VERSION << QCA_HDR_XMIT_VERSION_S |
  57                QCA_HDR_XMIT_FROM_CPU | BIT(dp->index);
  58
  59        *phdr = htons(hdr);
  60
  61        return skb;
  62}
  63
  64static struct sk_buff *qca_tag_rcv(struct sk_buff *skb, struct net_device *dev,
  65                                   struct packet_type *pt)
  66{
  67        u8 ver;
  68        int port;
  69        __be16 *phdr, hdr;
  70
  71        if (unlikely(!pskb_may_pull(skb, QCA_HDR_LEN)))
  72                return NULL;
  73
  74        /* The QCA header is added by the switch between src addr and Ethertype
  75         * At this point, skb->data points to ethertype so header should be
  76         * right before
  77         */
  78        phdr = (__be16 *)(skb->data - 2);
  79        hdr = ntohs(*phdr);
  80
  81        /* Make sure the version is correct */
  82        ver = (hdr & QCA_HDR_RECV_VERSION_MASK) >> QCA_HDR_RECV_VERSION_S;
  83        if (unlikely(ver != QCA_HDR_VERSION))
  84                return NULL;
  85
  86        /* Remove QCA tag and recalculate checksum */
  87        skb_pull_rcsum(skb, QCA_HDR_LEN);
  88        memmove(skb->data - ETH_HLEN, skb->data - ETH_HLEN - QCA_HDR_LEN,
  89                ETH_HLEN - QCA_HDR_LEN);
  90
  91        /* Get source port information */
  92        port = (hdr & QCA_HDR_RECV_SOURCE_PORT_MASK);
  93
  94        skb->dev = dsa_master_find_slave(dev, 0, port);
  95        if (!skb->dev)
  96                return NULL;
  97
  98        return skb;
  99}
 100
 101const struct dsa_device_ops qca_netdev_ops = {
 102        .xmit   = qca_tag_xmit,
 103        .rcv    = qca_tag_rcv,
 104        .overhead = QCA_HDR_LEN,
 105};
 106