[socket] Add concept of a generalised socket address converter

Add sock_aton() and sock_ntoa() to allow for parsing and transcription
of arbitrary socket addresses.

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

src/include/ipxe/errfile.h

@@ -215,6 +215,7 @@ FILE_LICENCE ( GPL2_OR_LATER );
 #define ERRFILE_mount			( ERRFILE_NET | 0x00350000 )
 #define ERRFILE_oncrpc_iob		( ERRFILE_NET | 0x00360000 )
 #define ERRFILE_neighbour		( ERRFILE_NET | 0x00370000 )
+#define ERRFILE_socket			( ERRFILE_NET | 0x00380000 )
 
 #define ERRFILE_image		      ( ERRFILE_IMAGE | 0x00000000 )
 #define ERRFILE_elf		      ( ERRFILE_IMAGE | 0x00010000 )

src/include/ipxe/socket.h

@@ -10,6 +10,7 @@
 FILE_LICENCE ( GPL2_OR_LATER );
 
 #include <stdint.h>
+#include <ipxe/tables.h>
 
 /**
  * @defgroup commtypes Communication semantics
@@ -99,4 +100,39 @@ struct sockaddr {
 	char pad[ SA_LEN - sizeof ( sa_family_t ) ];
 } __attribute__ (( may_alias ));
 
+/**
+ * Socket address converter
+ *
+ */
+struct sockaddr_converter {
+	/** Socket address family
+	 *
+	 * This is an AF_XXX constant.
+	 */
+        sa_family_t family;
+	/** Transcribe socket address
+	 *
+	 * @v sa		Socket address
+	 * @ret string		Socket address string
+	 */
+	const char * ( * ntoa ) ( struct sockaddr *sa );
+	/** Parse socket address
+	 *
+	 * @v string		Socket address stringh
+	 * @v sa		Socket address to fill in
+	 * @ret rc		Return status code
+	 */
+	int ( * aton ) ( const char *string, struct sockaddr *sa );
+};
+
+/** Socket address converter table */
+#define SOCKADDR_CONVERTERS \
+	__table ( struct sockaddr_converter, "sockaddr_converters" )
+
+/** Declare a socket address converter */
+#define __sockaddr_converter __table_entry ( SOCKADDR_CONVERTERS, 01 )
+
+extern const char * sock_ntoa ( struct sockaddr *sa );
+extern int sock_aton ( const char *string, struct sockaddr *sa );
+
 #endif /* _IPXE_SOCKET_H */

src/net/socket.c

@@ -0,0 +1,65 @@
+/*
+ * Copyright (C) 2013 Michael Brown <mbrown@fensystems.co.uk>.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER );
+
+#include <stddef.h>
+#include <errno.h>
+#include <ipxe/socket.h>
+
+/** @file
+ *
+ * Sockets
+ *
+ */
+
+/**
+ * Transcribe socket address
+ *
+ * @v sa		Socket address
+ * @ret string		Socket address string
+ */
+const char * sock_ntoa ( struct sockaddr *sa ) {
+	struct sockaddr_converter *converter;
+
+	for_each_table_entry ( converter, SOCKADDR_CONVERTERS ) {
+		if ( converter->family == sa->sa_family )
+			return converter->ntoa ( sa );
+	}
+	return NULL;
+}
+
+/**
+ * Parse socket address
+ *
+ * @v string		Socket address string
+ * @v sa		Socket address to fill in
+ * @ret rc		Return status code
+ */
+int sock_aton ( const char *string, struct sockaddr *sa ) {
+	struct sockaddr_converter *converter;
+
+	for_each_table_entry ( converter, SOCKADDR_CONVERTERS ) {
+		if ( converter->aton ( string, sa ) == 0 ) {
+			sa->sa_family = converter->family;
+			return 0;
+		}
+	}
+	return -EINVAL;
+}