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authorHerbert Xu <herbert@gondor.apana.org.au>2008-12-15 23:42:33 -0800
committerDavid S. Miller <davem@davemloft.net>2008-12-15 23:42:33 -0800
commit71d93b39e52e92aea35f1058d957cf12250d0b75 (patch)
tree270e3fe674d15467454504a99af2146c0324e08b /net/core
parent73cc19f1556b95976934de236fd9043f7208844f (diff)
net: Add skb_gro_receive
This patch adds the helper skb_gro_receive to merge packets for GRO. The current method is to allocate a new header skb and then chain the original packets to its frag_list. This is done to make it easier to integrate into the existing GSO framework. In future as GSO is moved into the drivers, we can undo this and simply chain the original packets together. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/core')
-rw-r--r--net/core/skbuff.c59
1 files changed, 59 insertions, 0 deletions
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 18e224af05a..b8d0abb2643 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -2582,6 +2582,65 @@ err:
EXPORT_SYMBOL_GPL(skb_segment);
+int skb_gro_receive(struct sk_buff **head, struct sk_buff *skb)
+{
+ struct sk_buff *p = *head;
+ struct sk_buff *nskb;
+ unsigned int headroom;
+ unsigned int hlen = p->data - skb_mac_header(p);
+
+ if (hlen + p->len + skb->len >= 65536)
+ return -E2BIG;
+
+ if (skb_shinfo(p)->frag_list)
+ goto merge;
+
+ headroom = skb_headroom(p);
+ nskb = netdev_alloc_skb(p->dev, headroom);
+ if (unlikely(!nskb))
+ return -ENOMEM;
+
+ __copy_skb_header(nskb, p);
+ nskb->mac_len = p->mac_len;
+
+ skb_reserve(nskb, headroom);
+
+ skb_set_mac_header(nskb, -hlen);
+ skb_set_network_header(nskb, skb_network_offset(p));
+ skb_set_transport_header(nskb, skb_transport_offset(p));
+
+ memcpy(skb_mac_header(nskb), skb_mac_header(p), hlen);
+
+ *NAPI_GRO_CB(nskb) = *NAPI_GRO_CB(p);
+ skb_shinfo(nskb)->frag_list = p;
+ skb_header_release(p);
+ nskb->prev = p;
+
+ nskb->data_len += p->len;
+ nskb->truesize += p->len;
+ nskb->len += p->len;
+
+ *head = nskb;
+ nskb->next = p->next;
+ p->next = NULL;
+
+ p = nskb;
+
+merge:
+ NAPI_GRO_CB(p)->count++;
+ p->prev->next = skb;
+ p->prev = skb;
+ skb_header_release(skb);
+
+ p->data_len += skb->len;
+ p->truesize += skb->len;
+ p->len += skb->len;
+
+ NAPI_GRO_CB(skb)->same_flow = 1;
+ return 0;
+}
+EXPORT_SYMBOL_GPL(skb_gro_receive);
+
void __init skb_init(void)
{
skbuff_head_cache = kmem_cache_create("skbuff_head_cache",