kernel: fix IPv6 TCP GSO segmentation with NAT
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Add missing checksum update

Fixes: https://github.com/openwrt/openwrt/issues/15857
Signed-off-by: Felix Fietkau <nbd@nbd.name>
(cherry picked from commit 00e4b23e27bd4ed3e0370b9b474ec53f72bd1282)
This commit is contained in:
Felix Fietkau 2025-02-24 12:26:01 +01:00
parent bb6f183e93
commit 8c1296f157

View File

@ -0,0 +1,54 @@
From: Felix Fietkau <nbd@nbd.name>
Date: Mon, 24 Feb 2025 12:18:23 +0100
Subject: [PATCH] net: ipv6: fix TCP GSO segmentation with NAT
When updating the source/destination address, the TCP/UDP checksum needs to
be updated as well.
Fixes: bee88cd5bd83 ("net: add support for segmenting TCP fraglist GSO packets")
Signed-off-by: Felix Fietkau <nbd@nbd.name>
---
--- a/net/ipv6/tcpv6_offload.c
+++ b/net/ipv6/tcpv6_offload.c
@@ -112,24 +112,36 @@ static struct sk_buff *__tcpv6_gso_segme
struct sk_buff *seg;
struct tcphdr *th2;
struct ipv6hdr *iph2;
+ bool addr_equal;
seg = segs;
th = tcp_hdr(seg);
iph = ipv6_hdr(seg);
th2 = tcp_hdr(seg->next);
iph2 = ipv6_hdr(seg->next);
+ addr_equal = ipv6_addr_equal(&iph->saddr, &iph2->saddr) &&
+ ipv6_addr_equal(&iph->daddr, &iph2->daddr);
if (!(*(const u32 *)&th->source ^ *(const u32 *)&th2->source) &&
- ipv6_addr_equal(&iph->saddr, &iph2->saddr) &&
- ipv6_addr_equal(&iph->daddr, &iph2->daddr))
+ addr_equal)
return segs;
while ((seg = seg->next)) {
th2 = tcp_hdr(seg);
iph2 = ipv6_hdr(seg);
- iph2->saddr = iph->saddr;
- iph2->daddr = iph->daddr;
+ if (!addr_equal) {
+ inet_proto_csum_replace16(&th2->check, seg,
+ iph2->saddr.s6_addr32,
+ iph->saddr.s6_addr32,
+ true);
+ inet_proto_csum_replace16(&th2->check, seg,
+ iph2->daddr.s6_addr32,
+ iph->daddr.s6_addr32,
+ true);
+ iph2->saddr = iph->saddr;
+ iph2->daddr = iph->daddr;
+ }
__tcpv6_gso_segment_csum(seg, &th2->source, th->source);
__tcpv6_gso_segment_csum(seg, &th2->dest, th->dest);
}