[PATCH net-next 1/3] net: core: add helper tcp_v6_gso_csum_prep

[Heiner Kallweit]

Several network drivers for chips that support TSO6 share the same code
for preparing the TCP header. A difference is that some reset the
payload_len whilst others don't do this. Let's factor out this common
code to a new helper.

Signed-off-by: Heiner Kallweit <hkallweit1@xxxxxxxxx>
---
 include/net/ip6_checksum.h | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/include/net/ip6_checksum.h b/include/net/ip6_checksum.h
index 7bec95df4..ef0130023 100644
--- a/include/net/ip6_checksum.h
+++ b/include/net/ip6_checksum.h
@@ -76,6 +76,18 @@ static inline void __tcp_v6_send_check(struct sk_buff *skb,
 	}
 }
 
+static inline void tcp_v6_gso_csum_prep(struct sk_buff *skb,
+					bool clear_payload_len)
+{
+	struct ipv6hdr *ipv6h = ipv6_hdr(skb);
+	struct tcphdr *th = tcp_hdr(skb);
+
+	if (clear_payload_len)
+		ipv6h->payload_len = 0;
+
+	th->check = ~tcp_v6_check(0, &ipv6h->saddr, &ipv6h->daddr, 0);
+}
+
 #if IS_ENABLED(CONFIG_IPV6)
 static inline void tcp_v6_send_check(struct sock *sk, struct sk_buff *skb)
 {
-- 
2.25.0