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| author | Tom Herbert <therbert@google.com> | 2014-06-04 17:20:02 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2014-06-04 22:46:38 -0700 |
| commit | 7e2b10c1e52ca37fb522be49f4be367f9311d0cd (patch) | |
| tree | 67fd8a9e9b90f732c45f406df145c8a149d24a53 /net/core | |
| parent | 77157e1973cbdb8d60bdb0ec749d6014bedc5bd5 (diff) | |
| download | linux-7e2b10c1e52ca37fb522be49f4be367f9311d0cd.tar.gz linux-7e2b10c1e52ca37fb522be49f4be367f9311d0cd.tar.bz2 linux-7e2b10c1e52ca37fb522be49f4be367f9311d0cd.zip | |
net: Support for multiple checksums with gso
When creating a GSO packet segment we may need to set more than
one checksum in the packet (for instance a TCP checksum and
UDP checksum for VXLAN encapsulation). To be efficient, we want
to do checksum calculation for any part of the packet at most once.
This patch adds csum_start offset to skb_gso_cb. This tracks the
starting offset for skb->csum which is initially set in skb_segment.
When a protocol needs to compute a transport checksum it calls
gso_make_checksum which computes the checksum value from the start
of transport header to csum_start and then adds in skb->csum to get
the full checksum. skb->csum and csum_start are then updated to reflect
the checksum of the resultant packet starting from the transport header.
This patch also adds a flag to skbuff, encap_hdr_csum, which is set
in *gso_segment fucntions to indicate that a tunnel protocol needs
checksum calculation
Signed-off-by: Tom Herbert <therbert@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/core')
| -rw-r--r-- | net/core/skbuff.c | 8 |
1 files changed, 7 insertions, 1 deletions
diff --git a/net/core/skbuff.c b/net/core/skbuff.c index 3f6c7e8be8a4..05f4bef2ce12 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -2885,7 +2885,9 @@ struct sk_buff *skb_segment(struct sk_buff *head_skb, if (unlikely(!proto)) return ERR_PTR(-EINVAL); - csum = !!can_checksum_protocol(features, proto); + csum = !head_skb->encap_hdr_csum && + !!can_checksum_protocol(features, proto); + __skb_push(head_skb, doffset); headroom = skb_headroom(head_skb); pos = skb_headlen(head_skb); @@ -2983,6 +2985,8 @@ struct sk_buff *skb_segment(struct sk_buff *head_skb, nskb->csum = skb_copy_and_csum_bits(head_skb, offset, skb_put(nskb, len), len, 0); + SKB_GSO_CB(nskb)->csum_start = + skb_headroom(nskb) + offset; continue; } @@ -3052,6 +3056,8 @@ perform_csum_check: nskb->csum = skb_checksum(nskb, doffset, nskb->len - doffset, 0); nskb->ip_summed = CHECKSUM_NONE; + SKB_GSO_CB(nskb)->csum_start = + skb_headroom(nskb) + doffset; } } while ((offset += len) < head_skb->len); |