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#include "dsa_priv.h"
  16
  17#define QCA_HDR_LEN     2
  18#define QCA_HDR_VERSION 0x2
  19
  20#define QCA_HDR_RECV_VERSION_MASK       GENMASK(15, 14)
  21#define QCA_HDR_RECV_VERSION_S          14
  22#define QCA_HDR_RECV_PRIORITY_MASK      GENMASK(13, 11)
  23#define QCA_HDR_RECV_PRIORITY_S         11
  24#define QCA_HDR_RECV_TYPE_MASK          GENMASK(10, 6)
  25#define QCA_HDR_RECV_TYPE_S             6
  26#define QCA_HDR_RECV_FRAME_IS_TAGGED    BIT(3)
  27#define QCA_HDR_RECV_SOURCE_PORT_MASK   GENMASK(2, 0)
  28
  29#define QCA_HDR_XMIT_VERSION_MASK       GENMASK(15, 14)
  30#define QCA_HDR_XMIT_VERSION_S          14
  31#define QCA_HDR_XMIT_PRIORITY_MASK      GENMASK(13, 11)
  32#define QCA_HDR_XMIT_PRIORITY_S         11
  33#define QCA_HDR_XMIT_CONTROL_MASK       GENMASK(10, 8)
  34#define QCA_HDR_XMIT_CONTROL_S          8
  35#define QCA_HDR_XMIT_FROM_CPU           BIT(7)
  36#define QCA_HDR_XMIT_DP_BIT_MASK        GENMASK(6, 0)
  37
  38static struct sk_buff *qca_tag_xmit(struct sk_buff *skb, struct net_device *dev)
  39{
  40        struct dsa_slave_priv *p = netdev_priv(dev);
  41        u16 *phdr, hdr;
  42
  43        dev->stats.tx_packets++;
  44        dev->stats.tx_bytes += skb->len;
  45
  46        if (skb_cow_head(skb, 0) < 0)
  47                goto out_free;
  48
  49        skb_push(skb, QCA_HDR_LEN);
  50
  51        memmove(skb->data, skb->data + QCA_HDR_LEN, 2 * ETH_ALEN);
  52        phdr = (u16 *)(skb->data + 2 * ETH_ALEN);
  53
  54        /* Set the version field, and set destination port information */
  55        hdr = QCA_HDR_VERSION << QCA_HDR_XMIT_VERSION_S |
  56                QCA_HDR_XMIT_FROM_CPU |
  57                BIT(p->port);
  58
  59        *phdr = htons(hdr);
  60
  61        return skb;
  62
  63out_free:
  64        kfree_skb(skb);
  65        return NULL;
  66}
  67
  68static int qca_tag_rcv(struct sk_buff *skb, struct net_device *dev,
  69                       struct packet_type *pt, struct net_device *orig_dev)
  70{
  71        struct dsa_switch_tree *dst = dev->dsa_ptr;
  72        struct dsa_switch *ds;
  73        u8 ver;
  74        int port;
  75        __be16 *phdr, hdr;
  76
  77        if (unlikely(!dst))
  78                goto out_drop;
  79
  80        skb = skb_unshare(skb, GFP_ATOMIC);
  81        if (!skb)
  82                goto out;
  83
  84        if (unlikely(!pskb_may_pull(skb, QCA_HDR_LEN)))
  85                goto out_drop;
  86
  87        /* The QCA header is added by the switch between src addr and Ethertype
  88         * At this point, skb->data points to ethertype so header should be
  89         * right before
  90         */
  91        phdr = (__be16 *)(skb->data - 2);
  92        hdr = ntohs(*phdr);
  93
  94        /* Make sure the version is correct */
  95        ver = (hdr & QCA_HDR_RECV_VERSION_MASK) >> QCA_HDR_RECV_VERSION_S;
  96        if (unlikely(ver != QCA_HDR_VERSION))
  97                goto out_drop;
  98
  99        /* Remove QCA tag and recalculate checksum */
 100        skb_pull_rcsum(skb, QCA_HDR_LEN);
 101        memmove(skb->data - ETH_HLEN, skb->data - ETH_HLEN - QCA_HDR_LEN,
 102                ETH_HLEN - QCA_HDR_LEN);
 103
 104        /* This protocol doesn't support cascading multiple switches so it's
 105         * safe to assume the switch is first in the tree
 106         */
 107        ds = dst->ds[0];
 108        if (!ds)
 109                goto out_drop;
 110
 111        /* Get source port information */
 112        port = (hdr & QCA_HDR_RECV_SOURCE_PORT_MASK);
 113        if (!ds->ports[port].netdev)
 114                goto out_drop;
 115
 116        /* Update skb & forward the frame accordingly */
 117        skb_push(skb, ETH_HLEN);
 118        skb->pkt_type = PACKET_HOST;
 119        skb->dev = ds->ports[port].netdev;
 120        skb->protocol = eth_type_trans(skb, skb->dev);
 121
 122        skb->dev->stats.rx_packets++;
 123        skb->dev->stats.rx_bytes += skb->len;
 124
 125        netif_receive_skb(skb);
 126
 127        return 0;
 128
 129out_drop:
 130        kfree_skb(skb);
 131out:
 132        return 0;
 133}
 134
 135const struct dsa_device_ops qca_netdev_ops = {
 136        .xmit   = qca_tag_xmit,
 137        .rcv    = qca_tag_rcv,
 138};
 139