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net: Fix test for VLAN TX checksum offload capability

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Selected device feature bits can be propagated to VLAN devices, so we
can make use of TX checksum offload and TSO on VLAN-tagged packets.
However, if the physical device does not do VLAN tag insertion or
generic checksum offload then the test for TX checksum offload in
dev_queue_xmit() will see a protocol of htons(ETH_P_8021Q) and yield
false.

This splits the checksum offload test into two functions:

- can_checksum_protocol() tests a given protocol against a feature bitmask

- dev_can_checksum() first tests the skb protocol against the device
  features; if that fails and the protocol is htons(ETH_P_8021Q) then
  it tests the encapsulated protocol against the effective device
  features for VLANs

Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
Acked-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Ben Hutchings 2008-06-16 17:02:28 -07:00 committed by David S. Miller
parent 319fa2a24f
commit 6de329e26c
1 changed files with 26 additions and 8 deletions
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34
net/core/dev.c
View File

@ -119,6 +119,7 @@
#include <linux/err.h>
#include <linux/ctype.h>
#include <linux/if_arp.h>
#include <linux/if_vlan.h>
#include "net-sysfs.h"
@ -1362,6 +1363,29 @@ void netif_device_attach(struct net_device *dev)
}
EXPORT_SYMBOL(netif_device_attach);
static bool can_checksum_protocol(unsigned long features, __be16 protocol)
{
return ((features & NETIF_F_GEN_CSUM) ||
((features & NETIF_F_IP_CSUM) &&
protocol == htons(ETH_P_IP)) ||
((features & NETIF_F_IPV6_CSUM) &&
protocol == htons(ETH_P_IPV6)));
}
static bool dev_can_checksum(struct net_device *dev, struct sk_buff *skb)
{
if (can_checksum_protocol(dev->features, skb->protocol))
return true;
if (skb->protocol == htons(ETH_P_8021Q)) {
struct vlan_ethhdr *veh = (struct vlan_ethhdr *)skb->data;
if (can_checksum_protocol(dev->features & dev->vlan_features,
veh->h_vlan_encapsulated_proto))
return true;
}
return false;
}
/*
* Invalidate hardware checksum when packet is to be mangled, and
@ -1640,14 +1664,8 @@ int dev_queue_xmit(struct sk_buff *skb)
if (skb->ip_summed == CHECKSUM_PARTIAL) {
skb_set_transport_header(skb, skb->csum_start -
skb_headroom(skb));
if (!(dev->features & NETIF_F_GEN_CSUM) &&
!((dev->features & NETIF_F_IP_CSUM) &&
skb->protocol == htons(ETH_P_IP)) &&
!((dev->features & NETIF_F_IPV6_CSUM) &&
skb->protocol == htons(ETH_P_IPV6)))
if (skb_checksum_help(skb))
goto out_kfree_skb;
if (!dev_can_checksum(dev, skb) && skb_checksum_help(skb))
goto out_kfree_skb;
}
gso: