/* 
   Unix SMB/CIFS implementation.

   SMB2 client library header

   Copyright (C) Andrew Tridgell 2005
   
   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 3 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, see <http://www.gnu.org/licenses/>.
*/

struct smb2_options {
	uint32_t timeout;
};

/*
  information returned from the negotiate response
*/
struct smb2_negotiate {
	DATA_BLOB secblob;
};

/* this is the context for the smb2 transport layer */
struct smb2_transport {
	/* socket level info */
	struct smbcli_socket *socket;

	struct smb2_options options;
	struct smb2_negotiate negotiate;

	/* next seqnum to allocate */
	uint64_t seqnum;

	/* a list of requests that are pending for receive on this
	   connection */
	struct smb2_request *pending_recv;

	/* context of the stream -> packet parser */
	struct packet_context *packet;

	/* an idle function - if this is defined then it will be
	   called once every period microseconds while we are waiting
	   for a packet */
	struct {
		void (*func)(struct smb2_transport *, void *);
		void *private;
		uint_t period;
	} idle;
};


/*
  SMB2 tree context
*/
struct smb2_tree {
	struct smb2_session *session;
	uint32_t tid;
};

/*
  SMB2 session context
*/
struct smb2_session {
	struct smb2_transport *transport;
	struct gensec_security *gensec;
	uint64_t uid;
	DATA_BLOB session_key;
};


struct smb2_request_buffer {
	/* the raw SMB2 buffer, including the 4 byte length header */
	uint8_t *buffer;
	
	/* the size of the raw buffer, including 4 byte header */
	size_t size;
	
	/* how much has been allocated - on reply the buffer is over-allocated to 
	   prevent too many realloc() calls 
	*/
	size_t allocated;
	
	/* the start of the SMB2 header - this is always buffer+4 */
	uint8_t *hdr;
	
	/* the packet body */
	uint8_t *body;
	size_t body_fixed;
	size_t body_size;

	/* this point to the next dynamic byte that can be used
	 * this will be moved when some dynamic data is pushed
	 */
	uint8_t *dynamic;
};


/*
  a client request moves between the following 4 states.
*/
enum smb2_request_state {SMB2_REQUEST_INIT, /* we are creating the request */
			SMB2_REQUEST_RECV, /* we are waiting for a matching reply */
			SMB2_REQUEST_DONE, /* the request is finished */
			SMB2_REQUEST_ERROR}; /* a packet or transport level error has occurred */

/* the context for a single SMB2 request */
struct smb2_request {
	/* allow a request to be part of a list of requests */
	struct smb2_request *next, *prev;

	/* each request is in one of 3 possible states */
	enum smb2_request_state state;
	
	struct smb2_transport *transport;
	struct smb2_session   *session;
	struct smb2_tree      *tree;

	uint64_t seqnum;

	struct {
		bool do_cancel;
		bool can_cancel;
		uint32_t pending_id;
	} cancel;

	/* the NT status for this request. Set by packet receive code
	   or code detecting error. */
	NTSTATUS status;
	
	struct smb2_request_buffer in;
	struct smb2_request_buffer out;

	/* information on what to do with a reply when it is received
	   asyncronously. If this is not setup when a reply is received then
	   the reply is discarded

	   The private pointer is private to the caller of the client
	   library (the application), not private to the library
	*/
	struct {
		void (*fn)(struct smb2_request *);
		void *private;
	} async;
};


#define SMB2_MIN_SIZE 0x42

/* offsets into header elements */
#define SMB2_HDR_LENGTH		0x04
#define SMB2_HDR_PAD1		0x06
#define SMB2_HDR_STATUS		0x08
#define SMB2_HDR_OPCODE		0x0c
#define SMB2_HDR_UNKNOWN1	0x0e
#define SMB2_HDR_FLAGS		0x10
#define SMB2_HDR_CHAIN_OFFSET	0x14
#define SMB2_HDR_SEQNUM		0x18
#define SMB2_HDR_PID		0x20
#define SMB2_HDR_TID		0x24
#define SMB2_HDR_UID		0x28 /* 64 bit */
#define SMB2_HDR_SIG		0x30 /* guess ... */
#define SMB2_HDR_BODY		0x40

/* SMB2 opcodes */
#define SMB2_OP_NEGPROT   0x00
#define SMB2_OP_SESSSETUP 0x01
#define SMB2_OP_LOGOFF    0x02
#define SMB2_OP_TCON      0x03
#define SMB2_OP_TDIS      0x04
#define SMB2_OP_CREATE    0x05
#define SMB2_OP_CLOSE     0x06
#define SMB2_OP_FLUSH     0x07
#define SMB2_OP_READ      0x08
#define SMB2_OP_WRITE     0x09
#define SMB2_OP_LOCK      0x0a
#define SMB2_OP_IOCTL     0x0b
#define SMB2_OP_CANCEL    0x0c
#define SMB2_OP_KEEPALIVE 0x0d
#define SMB2_OP_FIND      0x0e
#define SMB2_OP_NOTIFY    0x0f
#define SMB2_OP_GETINFO   0x10
#define SMB2_OP_SETINFO   0x11
#define SMB2_OP_BREAK     0x12

#define SMB2_MAGIC 0x424D53FE /* 0xFE 'S' 'M' 'B' */

/*
  check that a body has the expected size
*/
#define SMB2_CHECK_PACKET_RECV(req, size, dynamic) do { \
	size_t is_size = req->in.body_size; \
	uint16_t field_size = SVAL(req->in.body, 0); \
	uint16_t want_size = ((dynamic)?(size)+1:(size)); \
	if (is_size < (size)) { \
		DEBUG(0,("%s: buffer too small 0x%x. Expected 0x%x\n", \
			 __location__, (unsigned)is_size, (unsigned)want_size)); \
		return NT_STATUS_BUFFER_TOO_SMALL; \
	}\
	if (field_size != want_size) { \
		DEBUG(0,("%s: unexpected fixed body size 0x%x. Expected 0x%x\n", \
			 __location__, (unsigned)field_size, (unsigned)want_size)); \
		return NT_STATUS_INVALID_PARAMETER; \
	} \
} while (0)