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authorHerbert Xu <herbert@gondor.apana.org.au>2006-06-27 13:22:38 -0700
committerDavid S. Miller <davem@sunset.davemloft.net>2006-06-29 16:57:53 -0700
commit576a30eb6453439b3c37ba24455ac7090c247b5a (patch)
treee0c427a61e3de5c93e797c09903d910f6f060e64 /net/core/dev.c
parent68c1692e3ea5d79f24cb5cc566c4a73939d13d25 (diff)
[NET]: Added GSO header verification
When GSO packets come from an untrusted source (e.g., a Xen guest domain), we need to verify the header integrity before passing it to the hardware. Since the first step in GSO is to verify the header, we can reuse that code by adding a new bit to gso_type: SKB_GSO_DODGY. Packets with this bit set can only be fed directly to devices with the corresponding bit NETIF_F_GSO_ROBUST. If the device doesn't have that bit, then the skb is fed to the GSO engine which will allow the packet to be sent to the hardware if it passes the header check. This patch changes the sg flag to a full features flag. The same method can be used to implement TSO ECN support. We simply have to mark packets with CWR set with SKB_GSO_ECN so that only hardware with a corresponding NETIF_F_TSO_ECN can accept them. The GSO engine can either fully segment the packet, or segment the first MTU and pass the rest to the hardware for further segmentation. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/core/dev.c')
-rw-r--r--net/core/dev.c33
1 files changed, 24 insertions, 9 deletions
diff --git a/net/core/dev.c b/net/core/dev.c
index f1c52cbd6ef7..4f2014994a84 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -1190,11 +1190,14 @@ out:
/**
* skb_gso_segment - Perform segmentation on skb.
* @skb: buffer to segment
- * @sg: whether scatter-gather is supported on the target.
+ * @features: features for the output path (see dev->features)
*
* This function segments the given skb and returns a list of segments.
+ *
+ * It may return NULL if the skb requires no segmentation. This is
+ * only possible when GSO is used for verifying header integrity.
*/
-struct sk_buff *skb_gso_segment(struct sk_buff *skb, int sg)
+struct sk_buff *skb_gso_segment(struct sk_buff *skb, int features)
{
struct sk_buff *segs = ERR_PTR(-EPROTONOSUPPORT);
struct packet_type *ptype;
@@ -1210,12 +1213,14 @@ struct sk_buff *skb_gso_segment(struct sk_buff *skb, int sg)
rcu_read_lock();
list_for_each_entry_rcu(ptype, &ptype_base[ntohs(type) & 15], list) {
if (ptype->type == type && !ptype->dev && ptype->gso_segment) {
- segs = ptype->gso_segment(skb, sg);
+ segs = ptype->gso_segment(skb, features);
break;
}
}
rcu_read_unlock();
+ __skb_push(skb, skb->data - skb->mac.raw);
+
return segs;
}
@@ -1291,9 +1296,15 @@ static int dev_gso_segment(struct sk_buff *skb)
{
struct net_device *dev = skb->dev;
struct sk_buff *segs;
+ int features = dev->features & ~(illegal_highdma(dev, skb) ?
+ NETIF_F_SG : 0);
+
+ segs = skb_gso_segment(skb, features);
+
+ /* Verifying header integrity only. */
+ if (!segs)
+ return 0;
- segs = skb_gso_segment(skb, dev->features & NETIF_F_SG &&
- !illegal_highdma(dev, skb));
if (unlikely(IS_ERR(segs)))
return PTR_ERR(segs);
@@ -1310,13 +1321,17 @@ int dev_hard_start_xmit(struct sk_buff *skb, struct net_device *dev)
if (netdev_nit)
dev_queue_xmit_nit(skb, dev);
- if (!netif_needs_gso(dev, skb))
- return dev->hard_start_xmit(skb, dev);
+ if (netif_needs_gso(dev, skb)) {
+ if (unlikely(dev_gso_segment(skb)))
+ goto out_kfree_skb;
+ if (skb->next)
+ goto gso;
+ }
- if (unlikely(dev_gso_segment(skb)))
- goto out_kfree_skb;
+ return dev->hard_start_xmit(skb, dev);
}
+gso:
do {
struct sk_buff *nskb = skb->next;
int rc;