NFC: Initial LLCP support

This patch is an initial implementation for the NFC Logical Link Control
protocol. It's also known as NFC peer to peer mode.
This is a basic implementation as it lacks SDP (services Discovery
Protocol), frames aggregation support, and frame rejecion parsing.
Follow up patches will implement those missing features.
This code has been tested against a Nexus S phone implementing LLCP 1.0.

Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

Author: Samuel Ortiz

include/linux/nfc.h

@@ -139,9 +139,22 @@ struct sockaddr_nfc {
 	__u32 nfc_protocol;
 };
 
+#define NFC_LLCP_MAX_SERVICE_NAME 63
+struct sockaddr_nfc_llcp {
+	sa_family_t sa_family;
+	__u32 dev_idx;
+	__u32 target_idx;
+	__u32 nfc_protocol;
+	__u8 dsap; /* Destination SAP, if known */
+	__u8 ssap; /* Source SAP to be bound to */
+	char service_name[NFC_LLCP_MAX_SERVICE_NAME]; /* Service name URI */;
+	size_t service_name_len;
+};
+
 /* NFC socket protocols */
 #define NFC_SOCKPROTO_RAW	0
-#define NFC_SOCKPROTO_MAX	1
+#define NFC_SOCKPROTO_LLCP	1
+#define NFC_SOCKPROTO_MAX	2
 
 #define NFC_HEADER_SIZE 1
 

net/nfc/Kconfig

@@ -14,5 +14,6 @@ menuconfig NFC
 	  be called nfc.
 
 source "net/nfc/nci/Kconfig"
+source "net/nfc/llcp/Kconfig"
 
 source "drivers/nfc/Kconfig"

net/nfc/Makefile

@@ -6,3 +6,4 @@ obj-$(CONFIG_NFC) += nfc.o
 obj-$(CONFIG_NFC_NCI) += nci/
 
 nfc-objs := core.o netlink.o af_nfc.o rawsock.o
+nfc-$(CONFIG_NFC_LLCP)	+= llcp/llcp.o llcp/commands.o llcp/sock.o

net/nfc/core.c

@@ -240,6 +240,7 @@ int nfc_dep_link_down(struct nfc_dev *dev)
 	rc = dev->ops->dep_link_down(dev);
 	if (!rc) {
 		dev->dep_link_up = false;
+		nfc_llcp_mac_is_down(dev);
 		nfc_genl_dep_link_down_event(dev);
 	}
 
@@ -254,6 +255,8 @@ int nfc_dep_link_is_up(struct nfc_dev *dev, u32 target_idx,
 	dev->dep_link_up = true;
 	dev->dep_rf_mode = rf_mode;
 
+	nfc_llcp_mac_is_up(dev, target_idx, comm_mode, rf_mode);
+
 	return nfc_genl_dep_link_up_event(dev, target_idx, comm_mode, rf_mode);
 }
 EXPORT_SYMBOL(nfc_dep_link_is_up);
@@ -360,13 +363,13 @@ int nfc_set_remote_general_bytes(struct nfc_dev *dev, u8 *gb, u8 gb_len)
 	if (gb_len > NFC_MAX_GT_LEN)
 		return -EINVAL;
 
-	return 0;
+	return nfc_llcp_set_remote_gb(dev, gb, gb_len);
 }
 EXPORT_SYMBOL(nfc_set_remote_general_bytes);
 
 u8 *nfc_get_local_general_bytes(struct nfc_dev *dev, u8 *gt_len)
 {
-	return NULL;
+	return nfc_llcp_general_bytes(dev, gt_len);
 }
 EXPORT_SYMBOL(nfc_get_local_general_bytes);
 
@@ -560,6 +563,10 @@ int nfc_register_device(struct nfc_dev *dev)
 	if (rc < 0)
 		return rc;
 
+	rc = nfc_llcp_register_device(dev);
+	if (rc)
+		pr_err("Could not register llcp device\n");
+
 	rc = nfc_genl_device_added(dev);
 	if (rc)
 		pr_debug("The userspace won't be notified that the device %s was added\n",
@@ -591,6 +598,8 @@ void nfc_unregister_device(struct nfc_dev *dev)
 
 	mutex_unlock(&nfc_devlist_mutex);
 
+	nfc_llcp_unregister_device(dev);
+
 	rc = nfc_genl_device_removed(dev);
 	if (rc)
 		pr_debug("The userspace won't be notified that the device %s was removed\n",
@@ -620,13 +629,19 @@ static int __init nfc_init(void)
 	if (rc)
 		goto err_rawsock;
 
+	rc = nfc_llcp_init();
+	if (rc)
+		goto err_llcp_sock;
+
 	rc = af_nfc_init();
 	if (rc)
 		goto err_af_nfc;
 
 	return 0;
 
 err_af_nfc:
+	nfc_llcp_exit();
+err_llcp_sock:
 	rawsock_exit();
 err_rawsock:
 	nfc_genl_exit();
@@ -638,6 +653,7 @@ static int __init nfc_init(void)
 static void __exit nfc_exit(void)
 {
 	af_nfc_exit();
+	nfc_llcp_exit();
 	rawsock_exit();
 	nfc_genl_exit();
 	class_unregister(&nfc_class);

net/nfc/llcp/Kconfig

@@ -0,0 +1,7 @@
+config NFC_LLCP
+       depends on NFC && EXPERIMENTAL
+       bool "NFC LLCP support (EXPERIMENTAL)"
+       default n
+       help
+	 Say Y here if you want to build support for a kernel NFC LLCP
+	 implementation.