inet: add rfc 3168 extract in front of INET_ECN_encapsulate()
INET_ECN_encapsulate() is better understood if we can read the official
statement.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/inet_ecn.h b/include/net/inet_ecn.h
index 2fa8d13..2fa1469 100644
--- a/include/net/inet_ecn.h
+++ b/include/net/inet_ecn.h
@@ -30,6 +30,14 @@
return dsfield & INET_ECN_ECT_0;
}
+/*
+ * RFC 3168 9.1.1
+ * The full-functionality option for ECN encapsulation is to copy the
+ * ECN codepoint of the inside header to the outside header on
+ * encapsulation if the inside header is not-ECT or ECT, and to set the
+ * ECN codepoint of the outside header to ECT(0) if the ECN codepoint of
+ * the inside header is CE.
+ */
static inline __u8 INET_ECN_encapsulate(__u8 outer, __u8 inner)
{
outer &= ~INET_ECN_MASK;
