[TCP]: MD5 Signature Option (RFC2385) support.

Based on implementation by Rick Payne.

Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/Kconfig b/net/ipv4/Kconfig
index bc298bc..39e0cb7 100644
--- a/net/ipv4/Kconfig
+++ b/net/ipv4/Kconfig
@@ -618,5 +618,21 @@
 	default "reno" if DEFAULT_RENO
 	default "cubic"
 
+config TCP_MD5SIG
+	bool "TCP: MD5 Signature Option support (RFC2385) (EXPERIMENTAL)"
+	depends on EXPERIMENTAL
+	select CRYPTO
+	select CRYPTO_MD5
+	---help---
+	  RFC2385 specifices a method of giving MD5 protection to TCP sessions.
+	  Its main (only?) use is to protect BGP sessions between core routers
+	  on the Internet.
+
+	  If unsure, say N.
+
+config TCP_MD5SIG_DEBUG
+	bool "TCP: MD5 Signature Option debugging"
+	depends on TCP_MD5SIG
+
 source "net/ipv4/ipvs/Kconfig"