[ipv4] Redefine IP address constants to avoid unnecessary byte swapping

Redefine various IPv4 address constants and testing macros to avoid
unnecessary byte swapping at runtime, and slightly rename the macros
to prevent code from accidentally using the old definitions.

Signed-off-by: Michael Brown <mcb30@ipxe.org>

src/include/ipxe/in.h

@@ -4,6 +4,7 @@
 FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
 
 #include <stdint.h>
+#include <byteswap.h>
 #include <ipxe/socket.h>
 
 /* Protocol numbers */
@@ -15,17 +16,22 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
 
 /* IP address constants */
 
-#define INADDR_NONE 0xffffffff
+#define INADDR_NONE		htonl ( 0xffffffff )
 
-#define INADDR_BROADCAST 0xffffffff
+#define INADDR_BROADCAST	htonl ( 0xffffffff )
 
-#define	IN_CLASSA(addr)		( ( (addr) & 0x80000000 ) == 0x00000000 )
-#define	IN_CLASSA_NET		0xff000000
-#define	IN_CLASSB(addr)		( ( (addr) & 0xc0000000 ) == 0x80000000 )
-#define	IN_CLASSB_NET		0xffff0000
-#define	IN_CLASSC(addr)		( ( (addr) & 0xe0000000 ) == 0xc0000000 )
-#define	IN_CLASSC_NET		0xffffff00
-#define IN_MULTICAST(addr)	( ( (addr) & 0xf0000000 ) == 0xe0000000 )
+#define	INADDR_NET_CLASSA	htonl ( 0xff000000 )
+#define	INADDR_NET_CLASSB	htonl ( 0xffff0000 )
+#define	INADDR_NET_CLASSC	htonl ( 0xffffff00 )
+
+#define	IN_IS_CLASSA( addr ) \
+	( ( (addr) & htonl ( 0x80000000 ) ) == htonl ( 0x00000000 ) )
+#define	IN_IS_CLASSB( addr ) \
+	( ( (addr) & htonl ( 0xc0000000 ) ) == htonl ( 0x80000000 ) )
+#define	IN_IS_CLASSC( addr ) \
+	( ( (addr) & htonl ( 0xe0000000 ) ) == htonl ( 0xc0000000 ) )
+#define IN_IS_MULTICAST( addr ) \
+	( ( (addr) & htonl ( 0xf0000000 ) ) == htonl ( 0xe0000000 ) )
 
 /**
  * IP address structure

src/net/ipv4.c

@@ -314,7 +314,7 @@ static int ipv4_tx ( struct io_buffer *iobuf,
 	if ( sin_src )
 		iphdr->src = sin_src->sin_addr;
 	if ( ( next_hop.s_addr != INADDR_BROADCAST ) &&
-	     ( ! IN_MULTICAST ( ntohl ( next_hop.s_addr ) ) ) &&
+	     ( ! IN_IS_MULTICAST ( next_hop.s_addr ) ) &&
 	     ( ( miniroute = ipv4_route ( &next_hop ) ) != NULL ) ) {
 		iphdr->src = miniroute->address;
 		netmask = miniroute->netmask;
@@ -353,7 +353,7 @@ static int ipv4_tx ( struct io_buffer *iobuf,
 		/* Broadcast address */
 		ipv4_stats.out_bcast_pkts++;
 		ll_dest = netdev->ll_broadcast;
-	} else if ( IN_MULTICAST ( ntohl ( next_hop.s_addr ) ) ) {
+	} else if ( IN_IS_MULTICAST ( next_hop.s_addr ) ) {
 		/* Multicast address */
 		ipv4_stats.out_mcast_pkts++;
 		if ( ( rc = netdev->ll_protocol->mc_hash ( AF_INET, &next_hop,
@@ -816,12 +816,12 @@ static int ipv4_create_routes ( void ) {
 		fetch_ipv4_setting ( settings, &netmask_setting, &netmask );
 		/* Calculate default netmask, if necessary */
 		if ( ! netmask.s_addr ) {
-			if ( IN_CLASSA ( ntohl ( address.s_addr ) ) ) {
-				netmask.s_addr = htonl ( IN_CLASSA_NET );
-			} else if ( IN_CLASSB ( ntohl ( address.s_addr ) ) ) {
-				netmask.s_addr = htonl ( IN_CLASSB_NET );
-			} else if ( IN_CLASSC ( ntohl ( address.s_addr ) ) ) {
-				netmask.s_addr = htonl ( IN_CLASSC_NET );
+			if ( IN_IS_CLASSA ( address.s_addr ) ) {
+				netmask.s_addr = INADDR_NET_CLASSA;
+			} else if ( IN_IS_CLASSB ( address.s_addr ) ) {
+				netmask.s_addr = INADDR_NET_CLASSB;
+			} else if ( IN_IS_CLASSC ( address.s_addr ) ) {
+				netmask.s_addr = INADDR_NET_CLASSC;
 			}
 		}
 		/* Get default gateway, if present */

src/tests/ipv4_test.c

@@ -39,7 +39,8 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
 #include <ipxe/test.h>
 
 /** Define inline IPv4 address */
-#define IPV4(a,b,c,d) ( ( (a) << 24 ) | ( (b) << 16 ) | ( (c) << 8 ) | (d) )
+#define IPV4(a,b,c,d) \
+	htonl ( ( (a) << 24 ) | ( (b) << 16 ) | ( (c) << 8 ) | (d) )
 
 /**
  * Report an inet_ntoa() test result
@@ -51,7 +52,7 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
  */
 static void inet_ntoa_okx ( uint32_t addr, const char *text, const char *file,
 			    unsigned int line ) {
-	struct in_addr in = { .s_addr = htonl ( addr ) };
+	struct in_addr in = { .s_addr = addr };
 	char *actual;
 
 	/* Format address */
@@ -81,7 +82,7 @@ static void inet_aton_okx ( const char *text, uint32_t addr, const char *file,
 	/* Parse address */
 	okx ( inet_aton ( text, &actual ) != 0, file, line );
 	DBG ( "inet_aton ( \"%s\" ) = %s\n", text, inet_ntoa ( actual ) );
-	okx ( ntohl ( actual.s_addr ) == addr, file, line );
+	okx ( actual.s_addr == addr, file, line );
 };
 #define inet_aton_ok( text, addr ) \
 	inet_aton_okx ( text, addr, __FILE__, __LINE__ )
@@ -110,23 +111,23 @@ static void inet_aton_fail_okx ( const char *text, const char *file,
 static void ipv4_test_exec ( void ) {
 
 	/* Address testing macros */
-	ok (   IN_CLASSA ( IPV4 ( 10, 0, 0, 1 ) ) );
-	ok ( ! IN_CLASSB ( IPV4 ( 10, 0, 0, 1 ) ) );
-	ok ( ! IN_CLASSC ( IPV4 ( 10, 0, 0, 1 ) ) );
-	ok ( ! IN_CLASSA ( IPV4 ( 172, 16, 0, 1 ) ) );
-	ok (   IN_CLASSB ( IPV4 ( 172, 16, 0, 1 ) ) );
-	ok ( ! IN_CLASSC ( IPV4 ( 172, 16, 0, 1 ) ) );
-	ok ( ! IN_CLASSA ( IPV4 ( 192, 168, 0, 1 ) ) );
-	ok ( ! IN_CLASSB ( IPV4 ( 192, 168, 0, 1 ) ) );
-	ok (   IN_CLASSC ( IPV4 ( 192, 168, 0, 1 ) ) );
-	ok ( ! IN_MULTICAST ( IPV4 ( 127, 0, 0, 1 ) ) );
-	ok ( ! IN_MULTICAST ( IPV4 ( 8, 8, 8, 8 ) ) );
-	ok ( ! IN_MULTICAST ( IPV4 ( 0, 0, 0, 0 ) ) );
-	ok ( ! IN_MULTICAST ( IPV4 ( 223, 0, 0, 1 ) ) );
-	ok ( ! IN_MULTICAST ( IPV4 ( 240, 0, 0, 1 ) ) );
-	ok (   IN_MULTICAST ( IPV4 ( 224, 0, 0, 1 ) ) );
-	ok (   IN_MULTICAST ( IPV4 ( 231, 89, 0, 2 ) ) );
-	ok (   IN_MULTICAST ( IPV4 ( 239, 6, 1, 17 ) ) );
+	ok (   IN_IS_CLASSA ( IPV4 ( 10, 0, 0, 1 ) ) );
+	ok ( ! IN_IS_CLASSB ( IPV4 ( 10, 0, 0, 1 ) ) );
+	ok ( ! IN_IS_CLASSC ( IPV4 ( 10, 0, 0, 1 ) ) );
+	ok ( ! IN_IS_CLASSA ( IPV4 ( 172, 16, 0, 1 ) ) );
+	ok (   IN_IS_CLASSB ( IPV4 ( 172, 16, 0, 1 ) ) );
+	ok ( ! IN_IS_CLASSC ( IPV4 ( 172, 16, 0, 1 ) ) );
+	ok ( ! IN_IS_CLASSA ( IPV4 ( 192, 168, 0, 1 ) ) );
+	ok ( ! IN_IS_CLASSB ( IPV4 ( 192, 168, 0, 1 ) ) );
+	ok (   IN_IS_CLASSC ( IPV4 ( 192, 168, 0, 1 ) ) );
+	ok ( ! IN_IS_MULTICAST ( IPV4 ( 127, 0, 0, 1 ) ) );
+	ok ( ! IN_IS_MULTICAST ( IPV4 ( 8, 8, 8, 8 ) ) );
+	ok ( ! IN_IS_MULTICAST ( IPV4 ( 0, 0, 0, 0 ) ) );
+	ok ( ! IN_IS_MULTICAST ( IPV4 ( 223, 0, 0, 1 ) ) );
+	ok ( ! IN_IS_MULTICAST ( IPV4 ( 240, 0, 0, 1 ) ) );
+	ok (   IN_IS_MULTICAST ( IPV4 ( 224, 0, 0, 1 ) ) );
+	ok (   IN_IS_MULTICAST ( IPV4 ( 231, 89, 0, 2 ) ) );
+	ok (   IN_IS_MULTICAST ( IPV4 ( 239, 6, 1, 17 ) ) );
 
 	/* inet_ntoa() tests */
 	inet_ntoa_ok ( IPV4 ( 127, 0, 0, 1 ), "127.0.0.1" );