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>
diff --git a/net/nfc/llcp/llcp.h b/net/nfc/llcp/llcp.h
new file mode 100644
index 0000000..0ad2e33
--- /dev/null
+++ b/net/nfc/llcp/llcp.h
@@ -0,0 +1,193 @@
+/*
+ * Copyright (C) 2011  Intel Corporation. All rights reserved.
+ *
+ * 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.
+ */
+
+enum llcp_state {
+	LLCP_CONNECTED = 1, /* wait_for_packet() wants that */
+	LLCP_CLOSED,
+	LLCP_BOUND,
+	LLCP_LISTEN,
+};
+
+#define LLCP_DEFAULT_LTO 100
+#define LLCP_DEFAULT_RW  1
+#define LLCP_DEFAULT_MIU 128
+
+#define LLCP_WKS_NUM_SAP   16
+#define LLCP_SDP_NUM_SAP   16
+#define LLCP_LOCAL_NUM_SAP 32
+#define LLCP_LOCAL_SAP_OFFSET (LLCP_WKS_NUM_SAP + LLCP_SDP_NUM_SAP)
+#define LLCP_MAX_SAP (LLCP_WKS_NUM_SAP + LLCP_SDP_NUM_SAP + LLCP_LOCAL_NUM_SAP)
+
+struct nfc_llcp_sock;
+
+struct nfc_llcp_local {
+	struct list_head list;
+	struct nfc_dev *dev;
+
+	struct mutex sdp_lock;
+	struct mutex socket_lock;
+
+	struct timer_list link_timer;
+	struct sk_buff_head tx_queue;
+	struct workqueue_struct	*tx_wq;
+	struct work_struct	 tx_work;
+	struct workqueue_struct	*rx_wq;
+	struct work_struct	 rx_work;
+	struct sk_buff *rx_pending;
+	struct workqueue_struct	*timeout_wq;
+	struct work_struct	 timeout_work;
+
+	u32 target_idx;
+	u8 rf_mode;
+	u8 comm_mode;
+	unsigned long local_wks;      /* Well known services */
+	unsigned long local_sdp;      /* Local services  */
+	unsigned long local_sap; /* Local SAPs, not available for discovery */
+
+	/* local */
+	u8 gb[NFC_MAX_GT_LEN];
+	u8 gb_len;
+
+	/* remote */
+	u8 remote_gb[NFC_MAX_GT_LEN];
+	u8 remote_gb_len;
+
+	u8  remote_version;
+	u16 remote_miu;
+	u16 remote_lto;
+	u8  remote_opt;
+	u16 remote_wks;
+	u8  remote_rw;
+
+	/* sockets array */
+	struct nfc_llcp_sock *sockets[LLCP_MAX_SAP];
+};
+
+struct nfc_llcp_sock {
+	struct sock sk;
+	struct list_head list;
+	struct nfc_dev *dev;
+	struct nfc_llcp_local *local;
+	u32 target_idx;
+	u32 nfc_protocol;
+
+	u8 ssap;
+	u8 dsap;
+	char *service_name;
+	size_t service_name_len;
+
+	/* Link variables */
+	u8 send_n;
+	u8 send_ack_n;
+	u8 recv_n;
+	u8 recv_ack_n;
+
+	/* Is the remote peer ready to receive */
+	u8 remote_ready;
+
+	struct sk_buff_head tx_queue;
+	struct sk_buff_head tx_pending_queue;
+	struct sk_buff_head tx_backlog_queue;
+
+	struct list_head accept_queue;
+	struct sock *parent;
+};
+
+#define nfc_llcp_sock(sk) ((struct nfc_llcp_sock *) (sk))
+#define nfc_llcp_dev(sk)  (nfc_llcp_sock((sk))->dev)
+
+#define LLCP_HEADER_SIZE   2
+#define LLCP_SEQUENCE_SIZE 1
+
+/* LLCP versions: 1.1 is 1.0 plus SDP */
+#define LLCP_VERSION_10 0x10
+#define LLCP_VERSION_11 0x11
+
+/* LLCP PDU types */
+#define LLCP_PDU_SYMM     0x0
+#define LLCP_PDU_PAX      0x1
+#define LLCP_PDU_AGF      0x2
+#define LLCP_PDU_UI       0x3
+#define LLCP_PDU_CONNECT  0x4
+#define LLCP_PDU_DISC     0x5
+#define LLCP_PDU_CC       0x6
+#define LLCP_PDU_DM       0x7
+#define LLCP_PDU_FRMR     0x8
+#define LLCP_PDU_SNL      0x9
+#define LLCP_PDU_I        0xc
+#define LLCP_PDU_RR       0xd
+#define LLCP_PDU_RNR      0xe
+
+/* Parameters TLV types */
+#define LLCP_TLV_VERSION 0x1
+#define LLCP_TLV_MIUX    0x2
+#define LLCP_TLV_WKS     0x3
+#define LLCP_TLV_LTO     0x4
+#define LLCP_TLV_RW      0x5
+#define LLCP_TLV_SN      0x6
+#define LLCP_TLV_OPT     0x7
+#define LLCP_TLV_SDREQ   0x8
+#define LLCP_TLV_SDRES   0x9
+#define LLCP_TLV_MAX     0xa
+
+/* Well known LLCP SAP */
+#define LLCP_SAP_SDP   0x1
+#define LLCP_SAP_IP    0x2
+#define LLCP_SAP_OBEX  0x3
+#define LLCP_SAP_SNEP  0x4
+#define LLCP_SAP_MAX   0xff
+
+/* Disconnection reason code */
+#define LLCP_DM_DISC    0x00
+#define LLCP_DM_NOCONN  0x01
+#define LLCP_DM_NOBOUND 0x02
+#define LLCP_DM_REJ     0x03
+
+
+struct nfc_llcp_local *nfc_llcp_find_local(struct nfc_dev *dev);
+u8 nfc_llcp_get_sdp_ssap(struct nfc_llcp_local *local,
+				struct nfc_llcp_sock *sock);
+u8 nfc_llcp_get_local_ssap(struct nfc_llcp_local *local);
+void nfc_llcp_put_ssap(struct nfc_llcp_local *local, u8 ssap);
+
+/* Sock API */
+struct sock *nfc_llcp_sock_alloc(struct socket *sock, int type, gfp_t gfp);
+void nfc_llcp_sock_free(struct nfc_llcp_sock *sock);
+void nfc_llcp_accept_unlink(struct sock *sk);
+void nfc_llcp_accept_enqueue(struct sock *parent, struct sock *sk);
+struct sock *nfc_llcp_accept_dequeue(struct sock *sk, struct socket *newsock);
+
+/* TLV API */
+int nfc_llcp_parse_tlv(struct nfc_llcp_local *local,
+			u8 *tlv_array, u16 tlv_array_len);
+
+/* Commands API */
+void nfc_llcp_recv(void *data, struct sk_buff *skb, int err);
+u8 *nfc_llcp_build_tlv(u8 type, u8 *value, u8 value_length, u8 *tlv_length);
+void nfc_llcp_recv(void *data, struct sk_buff *skb, int err);
+int nfc_llcp_disconnect(struct nfc_llcp_sock *sock);
+int nfc_llcp_send_symm(struct nfc_dev *dev);
+int nfc_llcp_send_connect(struct nfc_llcp_sock *sock);
+int nfc_llcp_send_cc(struct nfc_llcp_sock *sock);
+int nfc_llcp_send_dm(struct nfc_llcp_local *local, u8 ssap, u8 dsap, u8 reason);
+int nfc_llcp_send_disconnect(struct nfc_llcp_sock *sock);
+
+/* Socket API */
+int __init nfc_llcp_sock_init(void);
+void nfc_llcp_sock_exit(void);