Commit b936a9b8 authored by Felix Fietkau's avatar Felix Fietkau Committed by Jakub Kicinski
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net: ipv6: fix UDPv6 GSO segmentation with NAT 



If any address or port is changed, update it in all packets and recalculate
checksum.

Fixes: 9fd1ff5d ("udp: Support UDP fraglist GRO/GSO.")
Signed-off-by: default avatarFelix Fietkau <nbd@nbd.name>
Reviewed-by: default avatarWillem de Bruijn <willemb@google.com>
Link: https://patch.msgid.link/20250426153210.14044-1-nbd@nbd.name


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 1e0bff3b

net/ipv4/udp_offload.c

+60 −1
Original line number Diff line number Diff line
@@ -247,6 +247,62 @@ static struct sk_buff *__udpv4_gso_segment_list_csum(struct sk_buff *segs) 
	return segs;

}



static void __udpv6_gso_segment_csum(struct sk_buff *seg,

				     struct in6_addr *oldip,

				     const struct in6_addr *newip,

				     __be16 *oldport, __be16 newport)

{

	struct udphdr *uh = udp_hdr(seg);



	if (ipv6_addr_equal(oldip, newip) && *oldport == newport)

		return;



	if (uh->check) {

		inet_proto_csum_replace16(&uh->check, seg, oldip->s6_addr32,

					  newip->s6_addr32, true);



		inet_proto_csum_replace2(&uh->check, seg, *oldport, newport,

					 false);

		if (!uh->check)

			uh->check = CSUM_MANGLED_0;

	}



	*oldip = *newip;

	*oldport = newport;

}



static struct sk_buff *__udpv6_gso_segment_list_csum(struct sk_buff *segs)

{

	const struct ipv6hdr *iph;

	const struct udphdr *uh;

	struct ipv6hdr *iph2;

	struct sk_buff *seg;

	struct udphdr *uh2;



	seg = segs;

	uh = udp_hdr(seg);

	iph = ipv6_hdr(seg);

	uh2 = udp_hdr(seg->next);

	iph2 = ipv6_hdr(seg->next);



	if (!(*(const u32 *)&uh->source ^ *(const u32 *)&uh2->source) &&

	    ipv6_addr_equal(&iph->saddr, &iph2->saddr) &&

	    ipv6_addr_equal(&iph->daddr, &iph2->daddr))

		return segs;



	while ((seg = seg->next)) {

		uh2 = udp_hdr(seg);

		iph2 = ipv6_hdr(seg);



		__udpv6_gso_segment_csum(seg, &iph2->saddr, &iph->saddr,

					 &uh2->source, uh->source);

		__udpv6_gso_segment_csum(seg, &iph2->daddr, &iph->daddr,

					 &uh2->dest, uh->dest);

	}



	return segs;

}



static struct sk_buff *__udp_gso_segment_list(struct sk_buff *skb,

					      netdev_features_t features,

					      bool is_ipv6)
@@ -259,7 +315,10 @@ static struct sk_buff *__udp_gso_segment_list(struct sk_buff *skb, 


	udp_hdr(skb)->len = htons(sizeof(struct udphdr) + mss);



	return is_ipv6 ? skb : __udpv4_gso_segment_list_csum(skb);

	if (is_ipv6)

		return __udpv6_gso_segment_list_csum(skb);

	else

		return __udpv4_gso_segment_list_csum(skb);

}



struct sk_buff *__udp_gso_segment(struct sk_buff *gso_skb,