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Commit 44540960 authored by Arnd Bergmann's avatar Arnd Bergmann Committed by David S. Miller
Browse files

veth: move loopback logic to common location 



The veth driver contains code to forward an skb
from the start_xmit function of one network
device into the receive path of another device.

Moving that code into a common location lets us
reuse the code for direct forwarding of data
between macvlan ports, and possibly in other
drivers.

Signed-off-by: default avatarArnd Bergmann <arnd@arndb.de>
Acked-by: default avatarPatrick McHardy <kaber@trash.net>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 1bda8aa8

drivers/net/veth.c

+3 −14
Original line number Diff line number Diff line
@@ -155,8 +155,6 @@ static netdev_tx_t veth_xmit(struct sk_buff *skb, struct net_device *dev) 
	struct veth_net_stats *stats, *rcv_stats;

	int length, cpu;



	skb_orphan(skb);



	priv = netdev_priv(dev);

	rcv = priv->peer;

	rcv_priv = netdev_priv(rcv);
@@ -168,20 +166,12 @@ static netdev_tx_t veth_xmit(struct sk_buff *skb, struct net_device *dev) 
	if (!(rcv->flags & IFF_UP))

		goto tx_drop;



	if (skb->len > (rcv->mtu + MTU_PAD))

		goto rx_drop;



        skb->tstamp.tv64 = 0;

	skb->pkt_type = PACKET_HOST;

	skb->protocol = eth_type_trans(skb, rcv);

	if (dev->features & NETIF_F_NO_CSUM)

		skb->ip_summed = rcv_priv->ip_summed;



	skb->mark = 0;

	secpath_reset(skb);

	nf_reset(skb);



	length = skb->len;

	length = skb->len + ETH_HLEN;

	if (dev_forward_skb(rcv, skb) != NET_RX_SUCCESS)

		goto rx_drop;



	stats->tx_bytes += length;

	stats->tx_packets++;
@@ -189,7 +179,6 @@ static netdev_tx_t veth_xmit(struct sk_buff *skb, struct net_device *dev) 
	rcv_stats->rx_bytes += length;

	rcv_stats->rx_packets++;



	netif_rx(skb);

	return NETDEV_TX_OK;



tx_drop:

include/linux/netdevice.h

+2 −0
Original line number Diff line number Diff line
@@ -1562,6 +1562,8 @@ extern int dev_set_mac_address(struct net_device *, 
extern int		dev_hard_start_xmit(struct sk_buff *skb,

					    struct net_device *dev,

					    struct netdev_queue *txq);

extern int		dev_forward_skb(struct net_device *dev,

					struct sk_buff *skb);



extern int		netdev_budget;

net/core/dev.c

+40 −0
Original line number Diff line number Diff line
@@ -105,6 +105,7 @@ 
#include <net/dst.h>

#include <net/pkt_sched.h>

#include <net/checksum.h>

#include <net/xfrm.h>

#include <linux/highmem.h>

#include <linux/init.h>

#include <linux/kmod.h>
@@ -1419,6 +1420,45 @@ static inline void net_timestamp(struct sk_buff *skb) 
		skb->tstamp.tv64 = 0;

}



/**

 * dev_forward_skb - loopback an skb to another netif

 *

 * @dev: destination network device

 * @skb: buffer to forward

 *

 * return values:

 *	NET_RX_SUCCESS	(no congestion)

 *	NET_RX_DROP     (packet was dropped)

 *

 * dev_forward_skb can be used for injecting an skb from the

 * start_xmit function of one device into the receive queue

 * of another device.

 *

 * The receiving device may be in another namespace, so

 * we have to clear all information in the skb that could

 * impact namespace isolation.

 */

int dev_forward_skb(struct net_device *dev, struct sk_buff *skb)

{

	skb_orphan(skb);



	if (!(dev->flags & IFF_UP))

		return NET_RX_DROP;



	if (skb->len > (dev->mtu + dev->hard_header_len))

		return NET_RX_DROP;



	skb_dst_drop(skb);

	skb->tstamp.tv64 = 0;

	skb->pkt_type = PACKET_HOST;

	skb->protocol = eth_type_trans(skb, dev);

	skb->mark = 0;

	secpath_reset(skb);

	nf_reset(skb);

	return netif_rx(skb);

}

EXPORT_SYMBOL_GPL(dev_forward_skb);



/*

 *	Support routine. Sends outgoing frames to any network

 *	taps currently in use.