Commit 7fbeffed authored by Alexander Duyck's avatar Alexander Duyck Committed by David S. Miller
Browse files

net: Update remote checksum segmentation to support use of GSO checksum 



This patch addresses two main issues.

First in the case of remote checksum offload we were avoiding dealing with
scatter-gather issues.  As a result it would be possible to assemble a
series of frames that used frags instead of being linearized as they should
have if remote checksum offload was enabled.

Second I have updated the code so that we now let GSO take care of doing
the checksum on the data itself and drop the special case that was added
for remote checksum offload.

Signed-off-by: default avatarAlexander Duyck <aduyck@mirantis.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 76443456

net/core/skbuff.c

+6 −4
Original line number Diff line number Diff line
@@ -3098,7 +3098,8 @@ struct sk_buff *skb_segment(struct sk_buff *head_skb, 
		if (nskb->len == len + doffset)

			goto perform_csum_check;



		if (!sg && !nskb->remcsum_offload) {

		if (!sg) {

			if (!nskb->remcsum_offload)

				nskb->ip_summed = CHECKSUM_NONE;

			SKB_GSO_CB(nskb)->csum =

				skb_copy_and_csum_bits(head_skb, offset,
@@ -3171,7 +3172,8 @@ skip_fraglist: 
		nskb->truesize += nskb->data_len;



perform_csum_check:

		if (!csum && !nskb->remcsum_offload) {

		if (!csum) {

			if (!nskb->remcsum_offload)

				nskb->ip_summed = CHECKSUM_NONE;

			SKB_GSO_CB(nskb)->csum =

				skb_checksum(nskb, doffset,

net/ipv4/udp_offload.c

+10 −12
Original line number Diff line number Diff line
@@ -66,6 +66,16 @@ static struct sk_buff *__skb_udp_tunnel_segment(struct sk_buff *skb, 


	features &= skb->dev->hw_enc_features;



	/* The only checksum offload we care about from here on out is the

	 * outer one so strip the existing checksum feature flags and

	 * instead set the flag based on our outer checksum offload value.

	 */

	if (remcsum) {

		features &= ~NETIF_F_CSUM_MASK;

		if (offload_csum)

			features |= NETIF_F_HW_CSUM;

	}



	/* segment inner packet. */

	segs = gso_inner_segment(skb, features);

	if (IS_ERR_OR_NULL(segs)) {
@@ -116,18 +126,6 @@ static struct sk_buff *__skb_udp_tunnel_segment(struct sk_buff *skb, 
			skb->ip_summed = CHECKSUM_PARTIAL;

			skb->csum_start = skb_transport_header(skb) - skb->head;

			skb->csum_offset = offsetof(struct udphdr, check);

		} else if (remcsum) {

			/* Need to calculate checksum from scratch,

			 * inner checksums are never when doing

			 * remote_checksum_offload.

			 */



			skb->csum = skb_checksum(skb, udp_offset,

						 skb->len - udp_offset,

						 0);

			uh->check = csum_fold(skb->csum);

			if (uh->check == 0)

				uh->check = CSUM_MANGLED_0;

		} else {

			uh->check = gso_make_checksum(skb, ~uh->check);

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