SCTP: Fix build issues with SCTP AUTH.

SCTP-AUTH requires selection of CRYPTO, HMAC and SHA1 since
SHA1 is a MUST requirement for AUTH.  We also support SHA256,
but that's optional, so fix the code to treat it as such.
Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>

include/net/sctp/constants.h

@@ -441,11 +441,14 @@ enum {
 	SCTP_AUTH_HMAC_ID_RESERVED_0,
 	SCTP_AUTH_HMAC_ID_SHA1,
 	SCTP_AUTH_HMAC_ID_RESERVED_2,
-	SCTP_AUTH_HMAC_ID_SHA256
+#if defined (CONFIG_CRYPTO_SHA256) || defined (CONFIG_CRYPTO_SHA256_MODULE)
+	SCTP_AUTH_HMAC_ID_SHA256,
+#endif
+	__SCTP_AUTH_HMAC_MAX
 };
 
-#define SCTP_AUTH_HMAC_ID_MAX	SCTP_AUTH_HMAC_ID_SHA256
-#define SCTP_AUTH_NUM_HMACS (SCTP_AUTH_HMAC_ID_SHA256 + 1)
+#define SCTP_AUTH_HMAC_ID_MAX	__SCTP_AUTH_HMAC_MAX - 1
+#define SCTP_AUTH_NUM_HMACS 	__SCTP_AUTH_HMAC_MAX
 #define SCTP_SHA1_SIG_SIZE 20
 #define SCTP_SHA256_SIG_SIZE 32
 

net/sctp/Kconfig

@@ -6,9 +6,9 @@ menuconfig IP_SCTP
 	tristate "The SCTP Protocol (EXPERIMENTAL)"
 	depends on INET && EXPERIMENTAL
 	depends on IPV6 || IPV6=n
-	select CRYPTO if SCTP_HMAC_SHA1 || SCTP_HMAC_MD5
-	select CRYPTO_HMAC if SCTP_HMAC_SHA1 || SCTP_HMAC_MD5
-	select CRYPTO_SHA1 if SCTP_HMAC_SHA1
+	select CRYPTO
+	select CRYPTO_HMAC
+	select CRYPTO_SHA1
 	select CRYPTO_MD5 if SCTP_HMAC_MD5
 	---help---
 	  Stream Control Transmission Protocol

net/sctp/auth.c

@@ -54,11 +54,13 @@ static struct sctp_hmac sctp_hmac_list[SCTP_AUTH_NUM_HMACS] = {
 		/* id 2 is reserved as well */
 		.hmac_id = SCTP_AUTH_HMAC_ID_RESERVED_2,
 	},
+#if defined (CONFIG_CRYPTO_SHA256) || defined (CONFIG_CRYPTO_SHA256_MODULE)
 	{
 		.hmac_id = SCTP_AUTH_HMAC_ID_SHA256,
 		.hmac_name="hmac(sha256)",
 		.hmac_len = SCTP_SHA256_SIG_SIZE,
 	}
+#endif
 };