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Commit 34ae6a1a authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
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ipv6: update skb->csum when CE mark is propagated 



When a tunnel decapsulates the outer header, it has to comply
with RFC 6080 and eventually propagate CE mark into inner header.

It turns out IP6_ECN_set_ce() does not correctly update skb->csum
for CHECKSUM_COMPLETE packets, triggering infamous "hw csum failure"
messages and stack traces.

Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Acked-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 113c74d8

include/net/inet_ecn.h

+16 −3
Original line number Diff line number Diff line
@@ -111,11 +111,24 @@ static inline void ipv4_copy_dscp(unsigned int dscp, struct iphdr *inner) 


struct ipv6hdr;



static inline int IP6_ECN_set_ce(struct ipv6hdr *iph)

/* Note:

 * IP_ECN_set_ce() has to tweak IPV4 checksum when setting CE,

 * meaning both changes have no effect on skb->csum if/when CHECKSUM_COMPLETE

 * In IPv6 case, no checksum compensates the change in IPv6 header,

 * so we have to update skb->csum.

 */

static inline int IP6_ECN_set_ce(struct sk_buff *skb, struct ipv6hdr *iph)

{

	__be32 from, to;



	if (INET_ECN_is_not_ect(ipv6_get_dsfield(iph)))

		return 0;

	*(__be32*)iph |= htonl(INET_ECN_CE << 20);



	from = *(__be32 *)iph;

	to = from | htonl(INET_ECN_CE << 20);

	*(__be32 *)iph = to;

	if (skb->ip_summed == CHECKSUM_COMPLETE)

		skb->csum = csum_add(csum_sub(skb->csum, from), to);

	return 1;

}
@@ -142,7 +155,7 @@ static inline int INET_ECN_set_ce(struct sk_buff *skb) 
	case cpu_to_be16(ETH_P_IPV6):

		if (skb_network_header(skb) + sizeof(struct ipv6hdr) <=

		    skb_tail_pointer(skb))

			return IP6_ECN_set_ce(ipv6_hdr(skb));

			return IP6_ECN_set_ce(skb, ipv6_hdr(skb));

		break;

	}

net/ipv6/xfrm6_mode_tunnel.c

+1 −1
Original line number Diff line number Diff line
@@ -23,7 +23,7 @@ static inline void ipip6_ecn_decapsulate(struct sk_buff *skb) 
	struct ipv6hdr *inner_iph = ipipv6_hdr(skb);



	if (INET_ECN_is_ce(XFRM_MODE_SKB_CB(skb)->tos))

		IP6_ECN_set_ce(inner_iph);

		IP6_ECN_set_ce(skb, inner_iph);

}



/* Add encapsulation header.