From d938e50136b0bd7dbc56b250cd4363646e59c9fc Mon Sep 17 00:00:00 2001
From: Michael Brown <mcb30@ipxe.org>
Date: Wed, 20 Mar 2013 15:06:40 +0000
Subject: [PATCH] [uuid] Abstract UUID mangling code out to a separate
 uuid_mangle() function

Signed-off-by: Michael Brown <mcb30@ipxe.org>
---
 src/include/ipxe/uuid.h                | 19 +++++++++++++++++++
 src/interface/smbios/smbios_settings.c |  5 +----
 src/net/udp/dhcp.c                     |  4 +---
 3 files changed, 21 insertions(+), 7 deletions(-)

diff --git a/src/include/ipxe/uuid.h b/src/include/ipxe/uuid.h
index 5de56b94..ad515d0c 100644
--- a/src/include/ipxe/uuid.h
+++ b/src/include/ipxe/uuid.h
@@ -9,6 +9,7 @@
 FILE_LICENCE ( GPL2_OR_LATER );
 
 #include <stdint.h>
+#include <byteswap.h>
 
 /** A universally unique ID */
 union uuid {
@@ -28,6 +29,24 @@ union uuid {
 	uint8_t raw[16];
 };
 
+/**
+ * Change UUID endianness
+ *
+ * @v uuid		UUID
+ *
+ * RFC4122 defines UUIDs as being encoded in network byte order, but
+ * leaves some wriggle room for "explicit application or presentation
+ * protocol specification to the contrary".  PXE, EFI and SMBIOS
+ * (versions 2.6 and above) treat the first three fields as being
+ * little-endian.
+ */
+static inline void uuid_mangle ( union uuid *uuid ) {
+
+	__bswap_32s ( &uuid->canonical.a );
+	__bswap_16s ( &uuid->canonical.b );
+	__bswap_16s ( &uuid->canonical.c );
+}
+
 extern char * uuid_ntoa ( const union uuid *uuid );
 
 #endif /* _IPXE_UUID_H */
diff --git a/src/interface/smbios/smbios_settings.c b/src/interface/smbios/smbios_settings.c
index 4ca14476..663da968 100644
--- a/src/interface/smbios/smbios_settings.c
+++ b/src/interface/smbios/smbios_settings.c
@@ -22,7 +22,6 @@ FILE_LICENCE ( GPL2_OR_LATER );
 #include <stdint.h>
 #include <string.h>
 #include <errno.h>
-#include <byteswap.h>
 #include <ipxe/settings.h>
 #include <ipxe/init.h>
 #include <ipxe/uuid.h>
@@ -148,9 +147,7 @@ static int smbios_fetch ( struct settings *settings __unused,
 		     ( smbios_version() >= SMBIOS_VERSION ( 2, 6 ) ) ) {
 			DBG ( "SMBIOS detected mangled UUID\n" );
 			memcpy ( &uuid, &buf[tag_offset], sizeof ( uuid ) );
-			__bswap_32s ( &uuid.canonical.a );
-			__bswap_16s ( &uuid.canonical.b );
-			__bswap_16s ( &uuid.canonical.c );
+			uuid_mangle ( &uuid );
 			raw = &uuid;
 		}
 
diff --git a/src/net/udp/dhcp.c b/src/net/udp/dhcp.c
index 3f2c451e..762ae732 100644
--- a/src/net/udp/dhcp.c
+++ b/src/net/udp/dhcp.c
@@ -1049,9 +1049,7 @@ int dhcp_create_request ( struct dhcp_packet *dhcppkt,
 	client_uuid.type = DHCP_CLIENT_UUID_TYPE;
 	if ( ( len = fetch_uuid_setting ( NULL, &uuid_setting,
 					  &client_uuid.uuid ) ) >= 0 ) {
-		__bswap_32s ( &client_uuid.uuid.canonical.a );
-		__bswap_16s ( &client_uuid.uuid.canonical.b );
-		__bswap_16s ( &client_uuid.uuid.canonical.c );
+		uuid_mangle ( &client_uuid.uuid );
 		if ( ( rc = dhcppkt_store ( dhcppkt, DHCP_CLIENT_UUID,
 					    &client_uuid,
 					    sizeof ( client_uuid ) ) ) != 0 ) {