/*
   * linux/fs/lockd/clntxdr.c
   *
   * XDR functions to encode/decode NLM version 3 RPC arguments and results.
   * NLM version 3 is backwards compatible with NLM versions 1 and 2.
   *
   * 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
  
  /*
   * Declare the space requirements for NLM arguments and replies as
   * number of 32bit-words
   */
  #define NLM_cookie_sz		(1+(NLM_MAXCOOKIELEN>>2))
  #define NLM_caller_sz		(1+(NLMCLNT_OHSIZE>>2))
  #define NLM_owner_sz		(1+(NLMCLNT_OHSIZE>>2))
  #define NLM_fhandle_sz		(1+(NFS2_FHSIZE>>2))
  #define NLM_lock_sz		(3+NLM_caller_sz+NLM_owner_sz+NLM_fhandle_sz)
  #define NLM_holder_sz		(4+NLM_owner_sz)
  
  #define NLM_testargs_sz		(NLM_cookie_sz+1+NLM_lock_sz)
  #define NLM_lockargs_sz		(NLM_cookie_sz+4+NLM_lock_sz)
  #define NLM_cancargs_sz		(NLM_cookie_sz+2+NLM_lock_sz)
  #define NLM_unlockargs_sz	(NLM_cookie_sz+NLM_lock_sz)
  
  #define NLM_testres_sz		(NLM_cookie_sz+1+NLM_holder_sz)
  #define NLM_res_sz		(NLM_cookie_sz+1)
  #define NLM_norep_sz		(0)
  
  
  static s32 loff_t_to_s32(loff_t offset)
  {
  	s32 res;
  
  	if (offset >= NLM_OFFSET_MAX)
  		res = NLM_OFFSET_MAX;
  	else if (offset <= -NLM_OFFSET_MAX)
  		res = -NLM_OFFSET_MAX;
  	else
  		res = offset;
  	return res;
  }
  
  static void nlm_compute_offsets(const struct nlm_lock *lock,
  				u32 *l_offset, u32 *l_len)
  {
  	const struct file_lock *fl = &lock->fl;
  
  	BUG_ON(fl->fl_start > NLM_OFFSET_MAX);
  	BUG_ON(fl->fl_end > NLM_OFFSET_MAX &&
  				fl->fl_end != OFFSET_MAX);
  
  	*l_offset = loff_t_to_s32(fl->fl_start);
  	if (fl->fl_end == OFFSET_MAX)
  		*l_len = 0;
  	else
  		*l_len = loff_t_to_s32(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 NLMv3 basic data types
   *
   * Basic NLMv3 data types are not defined in an IETF standards
   * document.  X/Open has a description of these data types that
   * is useful.  See Chapter 10 of "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;
  
  	BUG_ON(length > XDR_MAX_NETOBJ);
  	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)
  {
  	BUG_ON(cookie->len > NLM_MAXCOOKIELEN);
  	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)
  {
  	BUG_ON(fh->size != NFS2_FHSIZE);
  	encode_netobj(xdr, (u8 *)&fh->data, NFS2_FHSIZE);
  }
  
  /*
   *	enum nlm_stats {
   *		LCK_GRANTED = 0,
   *		LCK_DENIED = 1,
   *		LCK_DENIED_NOLOCKS = 2,
   *		LCK_BLOCKED = 3,
   *		LCK_DENIED_GRACE_PERIOD = 4
   *	};
   *
   *
   *	struct nlm_stat {
   *		nlm_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_nlm_stat(struct xdr_stream *xdr,
  			    const __be32 stat)
  {
  	__be32 *p;
  
  	BUG_ON(be32_to_cpu(stat) > NLM_LCK_DENIED_GRACE_PERIOD);
  	p = xdr_reserve_space(xdr, 4);
  	*p = stat;
  }
  
  static int decode_nlm_stat(struct xdr_stream *xdr,
  			   __be32 *stat)
  {
  	__be32 *p;
  
  	p = xdr_inline_decode(xdr, 4);
  	if (unlikely(p == NULL))
  		goto out_overflow;
  	if (unlikely(*p > nlm_lck_denied_grace_period))
  		goto out_enum;
  	*stat = *p;
  	return 0;
  out_enum:
  	dprintk("%s: server returned invalid nlm_stats value: %u
  ",
  		__func__, be32_to_cpup(p));
  	return -EIO;
  out_overflow:
  	print_overflow_msg(__func__, xdr);
  	return -EIO;
  }
  
  /*
   *	struct nlm_holder {
   *		bool exclusive;
   *		int uppid;
   *		netobj oh;
   *		unsigned l_offset;
   *		unsigned l_len;
   *	};
   */
  static void encode_nlm_holder(struct xdr_stream *xdr,
  			      const struct nlm_res *result)
  {
  	const struct nlm_lock *lock = &result->lock;
  	u32 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);
  	nlm_compute_offsets(lock, &l_offset, &l_len);
  	*p++ = cpu_to_be32(l_offset);
  	*p   = cpu_to_be32(l_len);
  }
  
  static int decode_nlm_holder(struct xdr_stream *xdr, struct nlm_res *result)
  {
  	struct nlm_lock *lock = &result->lock;
  	struct file_lock *fl = &lock->fl;
  	u32 exclusive, l_offset, l_len;
  	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, 4 + 4);
  	if (unlikely(p == NULL))
  		goto out_overflow;
  
  	fl->fl_flags = FL_POSIX;
  	fl->fl_type  = exclusive != 0 ? F_WRLCK : F_RDLCK;
  	l_offset = be32_to_cpup(p++);
  	l_len = be32_to_cpup(p);
  	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;
  
  	BUG_ON(length > NLM_MAXSTRLEN);
  	p = xdr_reserve_space(xdr, 4 + length);
  	xdr_encode_opaque(p, name, length);
  }
  
  /*
   *	struct nlm_lock {
   *		string caller_name<LM_MAXSTRLEN>;
   *		netobj fh;
   *		netobj oh;
   *		int uppid;
   *		unsigned l_offset;
   *		unsigned l_len;
   *	};
   */
  static void encode_nlm_lock(struct xdr_stream *xdr,
  			    const struct nlm_lock *lock)
  {
  	u32 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 + 4 + 4);
  	*p++ = cpu_to_be32(lock->svid);
  
  	nlm_compute_offsets(lock, &l_offset, &l_len);
  	*p++ = cpu_to_be32(l_offset);
  	*p   = cpu_to_be32(l_len);
  }
  
  
  /*
   * NLMv3 XDR encode functions
   *
   * NLMv3 argument types are defined in Chapter 10 of The Open Group's
   * "Protocols for Interworking: XNFS, Version 3W".
   */
  
  /*
   *	struct nlm_testargs {
   *		netobj cookie;
   *		bool exclusive;
   *		struct nlm_lock alock;
   *	};
   */

  static void nlm_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_nlm_lock(xdr, lock);

  }
  
  /*
   *	struct nlm_lockargs {
   *		netobj cookie;
   *		bool block;
   *		bool exclusive;
   *		struct nlm_lock alock;
   *		bool reclaim;
   *		int state;
   *	};
   */

  static void nlm_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_nlm_lock(xdr, lock);
  	encode_bool(xdr, args->reclaim);
  	encode_int32(xdr, args->state);

  }
  
  /*
   *	struct nlm_cancargs {
   *		netobj cookie;
   *		bool block;
   *		bool exclusive;
   *		struct nlm_lock alock;
   *	};
   */

  static void nlm_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_nlm_lock(xdr, lock);

  }
  
  /*
   *	struct nlm_unlockargs {
   *		netobj cookie;
   *		struct nlm_lock alock;
   *	};
   */

  static void nlm_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_nlm_lock(xdr, lock);

  }
  
  /*
   *	struct nlm_res {
   *		netobj cookie;
   *		nlm_stat stat;
   *	};
   */

  static void nlm_xdr_enc_res(struct rpc_rqst *req,
  			    struct xdr_stream *xdr,
  			    const struct nlm_res *result)

  {

  	encode_cookie(xdr, &result->cookie);
  	encode_nlm_stat(xdr, result->status);

  }
  
  /*
   *	union nlm_testrply switch (nlm_stats stat) {
   *	case LCK_DENIED:
   *		struct nlm_holder holder;
   *	default:
   *		void;
   *	};
   *
   *	struct nlm_testres {
   *		netobj cookie;
   *		nlm_testrply test_stat;
   *	};
   */
  static void encode_nlm_testrply(struct xdr_stream *xdr,
  				const struct nlm_res *result)
  {
  	if (result->status == nlm_lck_denied)
  		encode_nlm_holder(xdr, result);
  }

  static void nlm_xdr_enc_testres(struct rpc_rqst *req,
  				struct xdr_stream *xdr,
  				const struct nlm_res *result)

  {

  	encode_cookie(xdr, &result->cookie);
  	encode_nlm_stat(xdr, result->status);
  	encode_nlm_testrply(xdr, result);

  }
  
  
  /*
   * NLMv3 XDR decode functions
   *
   * NLMv3 result types are defined in Chapter 10 of The Open Group's
   * "Protocols for Interworking: XNFS, Version 3W".
   */
  
  /*
   *	union nlm_testrply switch (nlm_stats stat) {
   *	case LCK_DENIED:
   *		struct nlm_holder holder;
   *	default:
   *		void;
   *	};
   *
   *	struct nlm_testres {
   *		netobj cookie;
   *		nlm_testrply test_stat;
   *	};
   */
  static int decode_nlm_testrply(struct xdr_stream *xdr,
  			       struct nlm_res *result)
  {
  	int error;
  
  	error = decode_nlm_stat(xdr, &result->status);
  	if (unlikely(error))
  		goto out;
  	if (result->status == nlm_lck_denied)
  		error = decode_nlm_holder(xdr, result);
  out:
  	return error;
  }

  static int nlm_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_nlm_testrply(xdr, result);

  out:
  	return error;
  }
  
  /*
   *	struct nlm_res {
   *		netobj cookie;
   *		nlm_stat stat;
   *	};
   */

  static int nlm_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_nlm_stat(xdr, &result->status);

  out:
  	return error;
  }
  
  
  /*
   * For NLM, a void procedure really returns nothing
   */
  #define nlm_xdr_dec_norep	NULL
  
  #define PROC(proc, argtype, restype)	\
  [NLMPROC_##proc] = {							\
  	.p_proc      = NLMPROC_##proc,					\

  	.p_encode    = (kxdreproc_t)nlm_xdr_enc_##argtype,		\

  	.p_decode    = (kxdrdproc_t)nlm_xdr_dec_##restype,		\

  	.p_arglen    = NLM_##argtype##_sz,				\
  	.p_replen    = NLM_##restype##_sz,				\
  	.p_statidx   = NLMPROC_##proc,					\
  	.p_name      = #proc,						\
  	}
  
  static struct rpc_procinfo	nlm_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),
  };
  
  static struct rpc_version	nlm_version1 = {
  		.number		= 1,
  		.nrprocs	= ARRAY_SIZE(nlm_procedures),
  		.procs		= nlm_procedures,
  };
  
  static struct rpc_version	nlm_version3 = {
  		.number		= 3,
  		.nrprocs	= ARRAY_SIZE(nlm_procedures),
  		.procs		= nlm_procedures,
  };
  
  static struct rpc_version	*nlm_versions[] = {
  	[1] = &nlm_version1,
  	[3] = &nlm_version3,
  #ifdef CONFIG_LOCKD_V4
  	[4] = &nlm_version4,
  #endif
  };
  
  static struct rpc_stat		nlm_rpc_stats;
  
  struct rpc_program		nlm_program = {
  		.name		= "lockd",
  		.number		= NLM_PROGRAM,
  		.nrvers		= ARRAY_SIZE(nlm_versions),
  		.version	= nlm_versions,
  		.stats		= &nlm_rpc_stats,
  };