NFC: add NFC socket family

Signed-off-by: Lauro Ramos Venancio <lauro.venancio@openbossa.org>
Signed-off-by: Aloisio Almeida Jr <aloisio.almeida@openbossa.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

include/linux/nfc.h

@@ -109,4 +109,7 @@ enum nfc_attrs {
 #define NFC_PROTO_ISO14443_MASK	(1 << NFC_PROTO_ISO14443)
 #define NFC_PROTO_NFC_DEP_MASK	(1 << NFC_PROTO_NFC_DEP)
 
+/* NFC socket protocols */
+#define NFC_SOCKPROTO_MAX	0
+
 #endif /*__LINUX_NFC_H */

include/linux/socket.h

@@ -192,7 +192,8 @@ struct ucred {
 #define AF_IEEE802154	36	/* IEEE802154 sockets		*/
 #define AF_CAIF		37	/* CAIF sockets			*/
 #define AF_ALG		38	/* Algorithm sockets		*/
-#define AF_MAX		39	/* For now.. */
+#define AF_NFC		39	/* NFC sockets			*/
+#define AF_MAX		40	/* For now.. */
 
 /* Protocol families, same as address families. */
 #define PF_UNSPEC	AF_UNSPEC
@@ -234,6 +235,7 @@ struct ucred {
 #define PF_IEEE802154	AF_IEEE802154
 #define PF_CAIF		AF_CAIF
 #define PF_ALG		AF_ALG
+#define PF_NFC		AF_NFC
 #define PF_MAX		AF_MAX
 
 /* Maximum queue length specifiable by listen.  */

net/core/sock.c

@@ -158,7 +158,7 @@ static const char *const af_family_key_strings[AF_MAX+1] = {
   "sk_lock-AF_TIPC"  , "sk_lock-AF_BLUETOOTH", "sk_lock-IUCV"        ,
   "sk_lock-AF_RXRPC" , "sk_lock-AF_ISDN"     , "sk_lock-AF_PHONET"   ,
   "sk_lock-AF_IEEE802154", "sk_lock-AF_CAIF" , "sk_lock-AF_ALG"      ,
-  "sk_lock-AF_MAX"
+  "sk_lock-AF_NFC"   , "sk_lock-AF_MAX"
 };
 static const char *const af_family_slock_key_strings[AF_MAX+1] = {
   "slock-AF_UNSPEC", "slock-AF_UNIX"     , "slock-AF_INET"     ,
@@ -174,7 +174,7 @@ static const char *const af_family_slock_key_strings[AF_MAX+1] = {
   "slock-AF_TIPC"  , "slock-AF_BLUETOOTH", "slock-AF_IUCV"     ,
   "slock-AF_RXRPC" , "slock-AF_ISDN"     , "slock-AF_PHONET"   ,
   "slock-AF_IEEE802154", "slock-AF_CAIF" , "slock-AF_ALG"      ,
-  "slock-AF_MAX"
+  "slock-AF_NFC"   , "slock-AF_MAX"
 };
 static const char *const af_family_clock_key_strings[AF_MAX+1] = {
   "clock-AF_UNSPEC", "clock-AF_UNIX"     , "clock-AF_INET"     ,
@@ -190,7 +190,7 @@ static const char *const af_family_clock_key_strings[AF_MAX+1] = {
   "clock-AF_TIPC"  , "clock-AF_BLUETOOTH", "clock-AF_IUCV"     ,
   "clock-AF_RXRPC" , "clock-AF_ISDN"     , "clock-AF_PHONET"   ,
   "clock-AF_IEEE802154", "clock-AF_CAIF" , "clock-AF_ALG"      ,
-  "clock-AF_MAX"
+  "clock-AF_NFC"   , "clock-AF_MAX"
 };
 
 /*

net/nfc/Makefile

@@ -4,4 +4,4 @@
 
 obj-$(CONFIG_NFC) += nfc.o
 
-nfc-objs := core.o netlink.o
+nfc-objs := core.o netlink.o af_nfc.o

net/nfc/af_nfc.c

+/*
+ * Copyright (C) 2011 Instituto Nokia de Tecnologia
+ *
+ * Authors:
+ *    Aloisio Almeida Jr <aloisio.almeida@openbossa.org>
+ *    Lauro Ramos Venancio <lauro.venancio@openbossa.org>
+ *
+ * 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
+ * (at your option) 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.,
+ * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ */
+
+#include <linux/nfc.h>
+
+#include "nfc.h"
+
+static DEFINE_RWLOCK(proto_tab_lock);
+static const struct nfc_protocol *proto_tab[NFC_SOCKPROTO_MAX];
+
+static int nfc_sock_create(struct net *net, struct socket *sock, int proto,
+								int kern)
+{
+	int rc = -EPROTONOSUPPORT;
+
+	if (net != &init_net)
+		return -EAFNOSUPPORT;
+
+	if (proto < 0 || proto >= NFC_SOCKPROTO_MAX)
+		return -EINVAL;
+
+	read_lock(&proto_tab_lock);
+	if (proto_tab[proto] &&	try_module_get(proto_tab[proto]->owner)) {
+		rc = proto_tab[proto]->create(net, sock, proto_tab[proto]);
+		module_put(proto_tab[proto]->owner);
+	}
+	read_unlock(&proto_tab_lock);
+
+	return rc;
+}
+
+static struct net_proto_family nfc_sock_family_ops = {
+	.owner  = THIS_MODULE,
+	.family = PF_NFC,
+	.create = nfc_sock_create,
+};
+
+int nfc_proto_register(const struct nfc_protocol *nfc_proto)
+{
+	int rc;
+
+	if (nfc_proto->id < 0 || nfc_proto->id >= NFC_SOCKPROTO_MAX)
+		return -EINVAL;
+
+	rc = proto_register(nfc_proto->proto, 0);
+	if (rc)
+		return rc;
+
+	write_lock(&proto_tab_lock);
+	if (proto_tab[nfc_proto->id])
+		rc = -EBUSY;
+	else
+		proto_tab[nfc_proto->id] = nfc_proto;
+	write_unlock(&proto_tab_lock);
+
+	return rc;
+}
+EXPORT_SYMBOL(nfc_proto_register);
+
+void nfc_proto_unregister(const struct nfc_protocol *nfc_proto)
+{
+	write_lock(&proto_tab_lock);
+	proto_tab[nfc_proto->id] = NULL;
+	write_unlock(&proto_tab_lock);
+
+	proto_unregister(nfc_proto->proto);
+}
+EXPORT_SYMBOL(nfc_proto_unregister);
+
+int __init af_nfc_init(void)
+{
+	return sock_register(&nfc_sock_family_ops);
+}
+
+void af_nfc_exit(void)
+{
+	sock_unregister(PF_NFC);
+}

net/nfc/core.c

@@ -432,8 +432,14 @@ static int __init nfc_init(void)
 	/* the first generation must not be 0 */
 	nfc_devlist_generation = 1;
 
+	rc = af_nfc_init();
+	if (rc)
+		goto err_af_nfc;
+
 	return 0;
 
+err_af_nfc:
+	nfc_genl_exit();
 err_genl:
 	class_unregister(&nfc_class);
 	return rc;
@@ -441,6 +447,7 @@ static int __init nfc_init(void)
 
 static void __exit nfc_exit(void)
 {
+	af_nfc_exit();
 	nfc_genl_exit();
 	class_unregister(&nfc_class);
 }

net/nfc/nfc.h

@@ -25,6 +25,7 @@
 #define __LOCAL_NFC_H
 
 #include <net/nfc.h>
+#include <net/sock.h>
 
 __attribute__((format (printf, 2, 3)))
 int nfc_printk(const char *level, const char *fmt, ...);
@@ -33,6 +34,19 @@ int nfc_printk(const char *level, const char *fmt, ...);
 #define nfc_err(fmt, arg...) nfc_printk(KERN_ERR, fmt, ##arg)
 #define nfc_dbg(fmt, arg...) pr_debug(fmt "\n", ##arg)
 
+struct nfc_protocol {
+	int id;
+	struct proto *proto;
+	struct module *owner;
+	int (*create)(struct net *net, struct socket *sock,
+			const struct nfc_protocol *nfc_proto);
+};
+
+int __init af_nfc_init(void);
+void af_nfc_exit(void);
+int nfc_proto_register(const struct nfc_protocol *nfc_proto);
+void nfc_proto_unregister(const struct nfc_protocol *nfc_proto);
+
 extern int nfc_devlist_generation;
 extern struct mutex nfc_devlist_mutex;