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authorAlice Mikityanska <alice@isovalent.com>2026-02-05 15:39:14 +0200
committerJakub Kicinski <kuba@kernel.org>2026-02-06 20:50:03 -0800
commitb2936b4fd56294e49d6c8e9152ea6c4982757c7d (patch)
tree09239f6aac9c4482707e969f395da685a5d6b1f0 /include/linux
parent5826eec8710c214f02f253c165d66a230f5a86c3 (diff)
net/ipv6: Introduce payload_len helpers
The next commits will transition away from using the hop-by-hop extension header to encode packet length for BIG TCP. Add wrappers around ip6->payload_len that return the actual value if it's non-zero, and calculate it from skb->len if payload_len is set to zero (and a symmetrical setter). The new helpers are used wherever the surrounding code supports the hop-by-hop jumbo header for BIG TCP IPv6, or the corresponding IPv4 code uses skb_ip_totlen (e.g., in include/net/netfilter/nf_tables_ipv6.h). No behavioral change in this commit. Signed-off-by: Alice Mikityanska <alice@isovalent.com> Acked-by: Paolo Abeni <pabeni@redhat.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Link: https://patch.msgid.link/20260205133925.526371-2-alice.kernel@fastmail.im Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'include/linux')
-rw-r--r--include/linux/ipv6.h22
1 files changed, 22 insertions, 0 deletions
diff --git a/include/linux/ipv6.h b/include/linux/ipv6.h
index 20aae8357dd1..57ab6c97ee7e 100644
--- a/include/linux/ipv6.h
+++ b/include/linux/ipv6.h
@@ -126,6 +126,28 @@ static inline unsigned int ipv6_transport_len(const struct sk_buff *skb)
skb_network_header_len(skb);
}
+static inline unsigned int
+ipv6_payload_len(const struct sk_buff *skb, const struct ipv6hdr *ip6)
+{
+ u32 len = ntohs(ip6->payload_len);
+
+ return (len || !skb_is_gso(skb) || !skb_is_gso_tcp(skb)) ?
+ len :
+ skb->len - skb_network_offset(skb) - sizeof(struct ipv6hdr);
+}
+
+static inline unsigned int skb_ipv6_payload_len(const struct sk_buff *skb)
+{
+ return ipv6_payload_len(skb, ipv6_hdr(skb));
+}
+
+#define IPV6_MAXPLEN 65535
+
+static inline void ipv6_set_payload_len(struct ipv6hdr *ip6, unsigned int len)
+{
+ ip6->payload_len = len <= IPV6_MAXPLEN ? htons(len) : 0;
+}
+
/*
This structure contains results of exthdrs parsing
as offsets from skb->nh.