net: Fix test for VLAN TX checksum offload capability
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>
diff --git a/net/core/dev.c b/net/core/dev.c
index 5829630..68d8df0 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -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 @@
}
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 @@
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: