/*
   * linux/fs/lockd/clnt4xdr.c
   *
   * XDR functions to encode/decode NLM version 4 RPC arguments and results.
   *
   * NLM client-side only.
   *
   * Copyright (C) 2010, Oracle.  All rights reserved.
   */
  
  #include <linux/types.h>
  #include <linux/sunrpc/xdr.h>
  #include <linux/sunrpc/clnt.h>
  #include <linux/sunrpc/stats.h>
  #include <linux/lockd/lockd.h>
  
  #define NLMDBG_FACILITY		NLMDBG_XDR
  
  #if (NLMCLNT_OHSIZE > XDR_MAX_NETOBJ)
  #  error "NLM host name cannot be larger than XDR_MAX_NETOBJ!"
  #endif
  
  #if (NLMCLNT_OHSIZE > NLM_MAXSTRLEN)
  #  error "NLM host name cannot be larger than NLM's maximum string length!"
  #endif
  
  /*
   * Declare the space requirements for NLM arguments and replies as
   * number of 32bit-words
   */
  #define NLM4_void_sz		(0)
  #define NLM4_cookie_sz		(1+(NLM_MAXCOOKIELEN>>2))
  #define NLM4_caller_sz		(1+(NLMCLNT_OHSIZE>>2))
  #define NLM4_owner_sz		(1+(NLMCLNT_OHSIZE>>2))
  #define NLM4_fhandle_sz		(1+(NFS3_FHSIZE>>2))
  #define NLM4_lock_sz		(5+NLM4_caller_sz+NLM4_owner_sz+NLM4_fhandle_sz)
  #define NLM4_holder_sz		(6+NLM4_owner_sz)
  
  #define NLM4_testargs_sz	(NLM4_cookie_sz+1+NLM4_lock_sz)
  #define NLM4_lockargs_sz	(NLM4_cookie_sz+4+NLM4_lock_sz)
  #define NLM4_cancargs_sz	(NLM4_cookie_sz+2+NLM4_lock_sz)
  #define NLM4_unlockargs_sz	(NLM4_cookie_sz+NLM4_lock_sz)
  
  #define NLM4_testres_sz		(NLM4_cookie_sz+1+NLM4_holder_sz)
  #define NLM4_res_sz		(NLM4_cookie_sz+1)
  #define NLM4_norep_sz		(0)
  
  
  static s64 loff_t_to_s64(loff_t offset)
  {
  	s64 res;
  
  	if (offset >= NLM4_OFFSET_MAX)
  		res = NLM4_OFFSET_MAX;
  	else if (offset <= -NLM4_OFFSET_MAX)
  		res = -NLM4_OFFSET_MAX;
  	else
  		res = offset;
  	return res;
  }
  
  static void nlm4_compute_offsets(const struct nlm_lock *lock,
  				 u64 *l_offset, u64 *l_len)
  {
  	const struct file_lock *fl = &lock->fl;
  
  	*l_offset = loff_t_to_s64(fl->fl_start);
  	if (fl->fl_end == OFFSET_MAX)
  		*l_len = 0;
  	else
  		*l_len = loff_t_to_s64(fl->fl_end - fl->fl_start + 1);
  }
  
  /*
   * Handle decode buffer overflows out-of-line.
   */
  static void print_overflow_msg(const char *func, const struct xdr_stream *xdr)
  {
  	dprintk("lockd: %s prematurely hit the end of our receive buffer. "
  		"Remaining buffer length is %tu words.
  ",
  		func, xdr->end - xdr->p);
  }
  
  
  /*
   * Encode/decode NLMv4 basic data types
   *
   * Basic NLMv4 data types are defined in Appendix II, section 6.1.4
   * of RFC 1813: "NFS Version 3 Protocol Specification" and in Chapter
   * 10 of X/Open's "Protocols for Interworking: XNFS, Version 3W".
   *
   * Not all basic data types have their own encoding and decoding
   * functions.  For run-time efficiency, some data types are encoded
   * or decoded inline.
   */
  
  static void encode_bool(struct xdr_stream *xdr, const int value)
  {
  	__be32 *p;
  
  	p = xdr_reserve_space(xdr, 4);
  	*p = value ? xdr_one : xdr_zero;
  }
  
  static void encode_int32(struct xdr_stream *xdr, const s32 value)
  {
  	__be32 *p;
  
  	p = xdr_reserve_space(xdr, 4);
  	*p = cpu_to_be32(value);
  }
  
  /*
   *	typedef opaque netobj<MAXNETOBJ_SZ>
   */
  static void encode_netobj(struct xdr_stream *xdr,
  			  const u8 *data, const unsigned int length)
  {
  	__be32 *p;
  
  	p = xdr_reserve_space(xdr, 4 + length);
  	xdr_encode_opaque(p, data, length);
  }
  
  static int decode_netobj(struct xdr_stream *xdr,
  			 struct xdr_netobj *obj)
  {
  	u32 length;
  	__be32 *p;
  
  	p = xdr_inline_decode(xdr, 4);
  	if (unlikely(p == NULL))
  		goto out_overflow;
  	length = be32_to_cpup(p++);
  	if (unlikely(length > XDR_MAX_NETOBJ))
  		goto out_size;
  	obj->len = length;
  	obj->data = (u8 *)p;
  	return 0;
  out_size:
  	dprintk("NFS: returned netobj was too long: %u
  ", length);
  	return -EIO;
  out_overflow:
  	print_overflow_msg(__func__, xdr);
  	return -EIO;
  }
  
  /*
   *	netobj cookie;
   */
  static void encode_cookie(struct xdr_stream *xdr,
  			  const struct nlm_cookie *cookie)
  {
  	encode_netobj(xdr, (u8 *)&cookie->data, cookie->len);
  }
  
  static int decode_cookie(struct xdr_stream *xdr,
  			     struct nlm_cookie *cookie)
  {
  	u32 length;
  	__be32 *p;
  
  	p = xdr_inline_decode(xdr, 4);
  	if (unlikely(p == NULL))
  		goto out_overflow;
  	length = be32_to_cpup(p++);
  	/* apparently HPUX can return empty cookies */
  	if (length == 0)
  		goto out_hpux;
  	if (length > NLM_MAXCOOKIELEN)
  		goto out_size;
  	p = xdr_inline_decode(xdr, length);
  	if (unlikely(p == NULL))
  		goto out_overflow;
  	cookie->len = length;
  	memcpy(cookie->data, p, length);
  	return 0;
  out_hpux:
  	cookie->len = 4;
  	memset(cookie->data, 0, 4);
  	return 0;
  out_size:
  	dprintk("NFS: returned cookie was too long: %u
  ", length);
  	return -EIO;
  out_overflow:
  	print_overflow_msg(__func__, xdr);
  	return -EIO;
  }
  
  /*
   *	netobj fh;
   */
  static void encode_fh(struct xdr_stream *xdr, const struct nfs_fh *fh)
  {
  	encode_netobj(xdr, (u8 *)&fh->data, fh->size);
  }
  
  /*
   *	enum nlm4_stats {
   *		NLM4_GRANTED = 0,
   *		NLM4_DENIED = 1,
   *		NLM4_DENIED_NOLOCKS = 2,
   *		NLM4_BLOCKED = 3,
   *		NLM4_DENIED_GRACE_PERIOD = 4,
   *		NLM4_DEADLCK = 5,
   *		NLM4_ROFS = 6,
   *		NLM4_STALE_FH = 7,
   *		NLM4_FBIG = 8,
   *		NLM4_FAILED = 9
   *	};
   *
   *	struct nlm4_stat {
   *		nlm4_stats stat;
   *	};
   *
   * NB: we don't swap bytes for the NLM status values.  The upper
   * layers deal directly with the status value in network byte
   * order.
   */
  static void encode_nlm4_stat(struct xdr_stream *xdr,
  			     const __be32 stat)
  {
  	__be32 *p;
  
  	BUG_ON(be32_to_cpu(stat) > NLM_FAILED);
  	p = xdr_reserve_space(xdr, 4);
  	*p = stat;
  }
  
  static int decode_nlm4_stat(struct xdr_stream *xdr, __be32 *stat)
  {
  	__be32 *p;
  
  	p = xdr_inline_decode(xdr, 4);
  	if (unlikely(p == NULL))
  		goto out_overflow;
  	if (unlikely(ntohl(*p) > ntohl(nlm4_failed)))
  		goto out_bad_xdr;
  	*stat = *p;
  	return 0;
  out_bad_xdr:
  	dprintk("%s: server returned invalid nlm4_stats value: %u
  ",
  			__func__, be32_to_cpup(p));
  	return -EIO;
  out_overflow:
  	print_overflow_msg(__func__, xdr);
  	return -EIO;
  }
  
  /*
   *	struct nlm4_holder {
   *		bool	exclusive;
   *		int32	svid;
   *		netobj	oh;
   *		uint64	l_offset;
   *		uint64	l_len;
   *	};
   */
  static void encode_nlm4_holder(struct xdr_stream *xdr,
  			       const struct nlm_res *result)
  {
  	const struct nlm_lock *lock = &result->lock;
  	u64 l_offset, l_len;
  	__be32 *p;
  
  	encode_bool(xdr, lock->fl.fl_type == F_RDLCK);
  	encode_int32(xdr, lock->svid);
  	encode_netobj(xdr, lock->oh.data, lock->oh.len);
  
  	p = xdr_reserve_space(xdr, 4 + 4);
  	nlm4_compute_offsets(lock, &l_offset, &l_len);
  	p = xdr_encode_hyper(p, l_offset);
  	xdr_encode_hyper(p, l_len);
  }
  
  static int decode_nlm4_holder(struct xdr_stream *xdr, struct nlm_res *result)
  {
  	struct nlm_lock *lock = &result->lock;
  	struct file_lock *fl = &lock->fl;
  	u64 l_offset, l_len;
  	u32 exclusive;
  	int error;
  	__be32 *p;
  	s32 end;
  
  	memset(lock, 0, sizeof(*lock));
  	locks_init_lock(fl);
  
  	p = xdr_inline_decode(xdr, 4 + 4);
  	if (unlikely(p == NULL))
  		goto out_overflow;
  	exclusive = be32_to_cpup(p++);
  	lock->svid = be32_to_cpup(p);
  	fl->fl_pid = (pid_t)lock->svid;
  
  	error = decode_netobj(xdr, &lock->oh);
  	if (unlikely(error))
  		goto out;
  
  	p = xdr_inline_decode(xdr, 8 + 8);
  	if (unlikely(p == NULL))
  		goto out_overflow;
  
  	fl->fl_flags = FL_POSIX;
  	fl->fl_type  = exclusive != 0 ? F_WRLCK : F_RDLCK;
  	p = xdr_decode_hyper(p, &l_offset);
  	xdr_decode_hyper(p, &l_len);
  	end = l_offset + l_len - 1;
  
  	fl->fl_start = (loff_t)l_offset;
  	if (l_len == 0 || end < 0)
  		fl->fl_end = OFFSET_MAX;
  	else
  		fl->fl_end = (loff_t)end;
  	error = 0;
  out:
  	return error;
  out_overflow:
  	print_overflow_msg(__func__, xdr);
  	return -EIO;
  }
  
  /*
   *	string caller_name<LM_MAXSTRLEN>;
   */
  static void encode_caller_name(struct xdr_stream *xdr, const char *name)
  {
  	/* NB: client-side does not set lock->len */
  	u32 length = strlen(name);
  	__be32 *p;
  
  	p = xdr_reserve_space(xdr, 4 + length);
  	xdr_encode_opaque(p, name, length);
  }
  
  /*
   *	struct nlm4_lock {
   *		string	caller_name<LM_MAXSTRLEN>;
   *		netobj	fh;
   *		netobj	oh;
   *		int32	svid;
   *		uint64	l_offset;
   *		uint64	l_len;
   *	};
   */
  static void encode_nlm4_lock(struct xdr_stream *xdr,
  			     const struct nlm_lock *lock)
  {
  	u64 l_offset, l_len;
  	__be32 *p;
  
  	encode_caller_name(xdr, lock->caller);
  	encode_fh(xdr, &lock->fh);
  	encode_netobj(xdr, lock->oh.data, lock->oh.len);
  
  	p = xdr_reserve_space(xdr, 4 + 8 + 8);
  	*p++ = cpu_to_be32(lock->svid);
  
  	nlm4_compute_offsets(lock, &l_offset, &l_len);
  	p = xdr_encode_hyper(p, l_offset);
  	xdr_encode_hyper(p, l_len);
  }
  
  
  /*
   * NLMv4 XDR encode functions
   *
   * NLMv4 argument types are defined in Appendix II of RFC 1813:
   * "NFS Version 3 Protocol Specification" and Chapter 10 of X/Open's
   * "Protocols for Interworking: XNFS, Version 3W".
   */
  
  /*
   *	struct nlm4_testargs {
   *		netobj cookie;
   *		bool exclusive;
   *		struct nlm4_lock alock;
   *	};
   */
  static void nlm4_xdr_enc_testargs(struct rpc_rqst *req,
  				  struct xdr_stream *xdr,
  				  const struct nlm_args *args)
  {
  	const struct nlm_lock *lock = &args->lock;
  
  	encode_cookie(xdr, &args->cookie);
  	encode_bool(xdr, lock->fl.fl_type == F_WRLCK);
  	encode_nlm4_lock(xdr, lock);
  }
  
  /*
   *	struct nlm4_lockargs {
   *		netobj cookie;
   *		bool block;
   *		bool exclusive;
   *		struct nlm4_lock alock;
   *		bool reclaim;
   *		int state;
   *	};
   */
  static void nlm4_xdr_enc_lockargs(struct rpc_rqst *req,
  				  struct xdr_stream *xdr,
  				  const struct nlm_args *args)
  {
  	const struct nlm_lock *lock = &args->lock;
  
  	encode_cookie(xdr, &args->cookie);
  	encode_bool(xdr, args->block);
  	encode_bool(xdr, lock->fl.fl_type == F_WRLCK);
  	encode_nlm4_lock(xdr, lock);
  	encode_bool(xdr, args->reclaim);
  	encode_int32(xdr, args->state);
  }
  
  /*
   *	struct nlm4_cancargs {
   *		netobj cookie;
   *		bool block;
   *		bool exclusive;
   *		struct nlm4_lock alock;
   *	};
   */
  static void nlm4_xdr_enc_cancargs(struct rpc_rqst *req,
  				  struct xdr_stream *xdr,
  				  const struct nlm_args *args)
  {
  	const struct nlm_lock *lock = &args->lock;
  
  	encode_cookie(xdr, &args->cookie);
  	encode_bool(xdr, args->block);
  	encode_bool(xdr, lock->fl.fl_type == F_WRLCK);
  	encode_nlm4_lock(xdr, lock);
  }
  
  /*
   *	struct nlm4_unlockargs {
   *		netobj cookie;
   *		struct nlm4_lock alock;
   *	};
   */
  static void nlm4_xdr_enc_unlockargs(struct rpc_rqst *req,
  				    struct xdr_stream *xdr,
  				    const struct nlm_args *args)
  {
  	const struct nlm_lock *lock = &args->lock;
  
  	encode_cookie(xdr, &args->cookie);
  	encode_nlm4_lock(xdr, lock);
  }
  
  /*
   *	struct nlm4_res {
   *		netobj cookie;
   *		nlm4_stat stat;
   *	};
   */
  static void nlm4_xdr_enc_res(struct rpc_rqst *req,
  			     struct xdr_stream *xdr,
  			     const struct nlm_res *result)
  {
  	encode_cookie(xdr, &result->cookie);
  	encode_nlm4_stat(xdr, result->status);
  }
  
  /*
   *	union nlm4_testrply switch (nlm4_stats stat) {
   *	case NLM4_DENIED:
   *		struct nlm4_holder holder;
   *	default:
   *		void;
   *	};
   *
   *	struct nlm4_testres {
   *		netobj cookie;
   *		nlm4_testrply test_stat;
   *	};
   */
  static void nlm4_xdr_enc_testres(struct rpc_rqst *req,
  				 struct xdr_stream *xdr,
  				 const struct nlm_res *result)
  {
  	encode_cookie(xdr, &result->cookie);
  	encode_nlm4_stat(xdr, result->status);
  	if (result->status == nlm_lck_denied)
  		encode_nlm4_holder(xdr, result);
  }
  
  
  /*
   * NLMv4 XDR decode functions
   *
   * NLMv4 argument types are defined in Appendix II of RFC 1813:
   * "NFS Version 3 Protocol Specification" and Chapter 10 of X/Open's
   * "Protocols for Interworking: XNFS, Version 3W".
   */
  
  /*
   *	union nlm4_testrply switch (nlm4_stats stat) {
   *	case NLM4_DENIED:
   *		struct nlm4_holder holder;
   *	default:
   *		void;
   *	};
   *
   *	struct nlm4_testres {
   *		netobj cookie;
   *		nlm4_testrply test_stat;
   *	};
   */
  static int decode_nlm4_testrply(struct xdr_stream *xdr,
  				struct nlm_res *result)
  {
  	int error;
  
  	error = decode_nlm4_stat(xdr, &result->status);
  	if (unlikely(error))
  		goto out;
  	if (result->status == nlm_lck_denied)
  		error = decode_nlm4_holder(xdr, result);
  out:
  	return error;
  }
  
  static int nlm4_xdr_dec_testres(struct rpc_rqst *req,
  				struct xdr_stream *xdr,
  				struct nlm_res *result)
  {
  	int error;
  
  	error = decode_cookie(xdr, &result->cookie);
  	if (unlikely(error))
  		goto out;
  	error = decode_nlm4_testrply(xdr, result);
  out:
  	return error;
  }
  
  /*
   *	struct nlm4_res {
   *		netobj cookie;
   *		nlm4_stat stat;
   *	};
   */
  static int nlm4_xdr_dec_res(struct rpc_rqst *req,
  			    struct xdr_stream *xdr,
  			    struct nlm_res *result)
  {
  	int error;
  
  	error = decode_cookie(xdr, &result->cookie);
  	if (unlikely(error))
  		goto out;
  	error = decode_nlm4_stat(xdr, &result->status);
  out:
  	return error;
  }
  
  
  /*
   * For NLM, a void procedure really returns nothing
   */
  #define nlm4_xdr_dec_norep	NULL
  
  #define PROC(proc, argtype, restype)					\
  [NLMPROC_##proc] = {							\
  	.p_proc      = NLMPROC_##proc,					\
  	.p_encode    = (kxdreproc_t)nlm4_xdr_enc_##argtype,		\
  	.p_decode    = (kxdrdproc_t)nlm4_xdr_dec_##restype,		\
  	.p_arglen    = NLM4_##argtype##_sz,				\
  	.p_replen    = NLM4_##restype##_sz,				\
  	.p_statidx   = NLMPROC_##proc,					\
  	.p_name      = #proc,						\
  	}
  
  static struct rpc_procinfo	nlm4_procedures[] = {
  	PROC(TEST,		testargs,	testres),
  	PROC(LOCK,		lockargs,	res),
  	PROC(CANCEL,		cancargs,	res),
  	PROC(UNLOCK,		unlockargs,	res),
  	PROC(GRANTED,		testargs,	res),
  	PROC(TEST_MSG,		testargs,	norep),
  	PROC(LOCK_MSG,		lockargs,	norep),
  	PROC(CANCEL_MSG,	cancargs,	norep),
  	PROC(UNLOCK_MSG,	unlockargs,	norep),
  	PROC(GRANTED_MSG,	testargs,	norep),
  	PROC(TEST_RES,		testres,	norep),
  	PROC(LOCK_RES,		res,		norep),
  	PROC(CANCEL_RES,	res,		norep),
  	PROC(UNLOCK_RES,	res,		norep),
  	PROC(GRANTED_RES,	res,		norep),
  };
  
  const struct rpc_version nlm_version4 = {
  	.number		= 4,
  	.nrprocs	= ARRAY_SIZE(nlm4_procedures),
  	.procs		= nlm4_procedures,
  };