/*
* Put the skb on the stack to be looped backed locally lateron
*
* The function is typically called in the start_xmit function
* of the device driver. The driver must protect access to
* priv->echo_skb, if necessary.
*/
void can_put_echo_skb(struct sk_buff *skb, struct net_device *dev,
unsigned int idx)
{
struct can_priv *priv = netdev_priv(dev);
BUG_ON(idx >= priv->echo_skb_max);
/* check flag whether this packet has to be looped back */
if (!(dev->flags & IFF_ECHO) || skb->pkt_type != PACKET_LOOPBACK ||
(skb->protocol != htons(ETH_P_CAN) &&
skb->protocol != htons(ETH_P_CANFD))) {
kfree_skb(skb);
return;
}
if (!priv->echo_skb[idx]) {
skb = can_create_echo_skb(skb);
if (!skb)
return;
/* make settings for echo to reduce code in irq context */
skb->pkt_type = PACKET_BROADCAST;
skb->ip_summed = CHECKSUM_UNNECESSARY;
skb->dev = dev;
/* save this skb for tx interrupt echo handling */
priv->echo_skb[idx] = skb;
} else {
/* locking problem with netif_stop_queue() ?? */
netdev_err(dev, "%s: BUG! echo_skb is occupied!\n", __func__);
kfree_skb(skb);
}
}
static netdev_tx_t vcan_tx(struct sk_buff *skb, struct net_device *dev)
{
struct canfd_frame *cfd = (struct canfd_frame *)skb->data;
struct net_device_stats *stats = &dev->stats;
int loop;
if (can_dropped_invalid_skb(dev, skb))
return NETDEV_TX_OK;
stats->tx_packets++;
stats->tx_bytes += cfd->len;
/* set flag whether this packet has to be looped back */
loop = skb->pkt_type == PACKET_LOOPBACK;
if (!echo) {
/* no echo handling available inside this driver */
if (loop) {
/*
* only count the packets here, because the
* CAN core already did the echo for us
*/
stats->rx_packets++;
stats->rx_bytes += cfd->len;
}
consume_skb(skb);
return NETDEV_TX_OK;
}
/* perform standard echo handling for CAN network interfaces */
if (loop) {
skb = can_create_echo_skb(skb);
if (!skb)
return NETDEV_TX_OK;
/* receive with packet counting */
vcan_rx(skb, dev);
} else {
/* no looped packets => no counting */
consume_skb(skb);
}
return NETDEV_TX_OK;
}
static netdev_tx_t vxcan_xmit(struct sk_buff *skb, struct net_device *dev)
{
struct vxcan_priv *priv = netdev_priv(dev);
struct net_device *peer;
struct canfd_frame *cfd = (struct canfd_frame *)skb->data;
struct net_device_stats *peerstats, *srcstats = &dev->stats;
if (can_dropped_invalid_skb(dev, skb))
return NETDEV_TX_OK;
rcu_read_lock();
peer = rcu_dereference(priv->peer);
if (unlikely(!peer)) {
kfree_skb(skb);
dev->stats.tx_dropped++;
goto out_unlock;
}
skb = can_create_echo_skb(skb);
if (!skb)
goto out_unlock;
/* reset CAN GW hop counter */
skb->csum_start = 0;
skb->pkt_type = PACKET_BROADCAST;
skb->dev = peer;
skb->ip_summed = CHECKSUM_UNNECESSARY;
if (netif_rx_ni(skb) == NET_RX_SUCCESS) {
srcstats->tx_packets++;
srcstats->tx_bytes += cfd->len;
peerstats = &peer->stats;
peerstats->rx_packets++;
peerstats->rx_bytes += cfd->len;
}
out_unlock:
rcu_read_unlock();
return NETDEV_TX_OK;
}