/*      $NetBSD: nfsm_subs.h,v 1.4 2016/12/13 22:52:46 pgoyette Exp $   */
/*-
* Copyright (c) 1989, 1993
*      The Regents of the University of California.  All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* Rick Macklem at The University of Guelph.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
*    notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
*    notice, this list of conditions and the following disclaimer in the
*    documentation and/or other materials provided with the distribution.
* 4. Neither the name of the University nor the names of its contributors
*    may be used to endorse or promote products derived from this software
*    without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* FreeBSD: head/sys/fs/nfs/nfsm_subs.h 276780 2015-01-07 17:22:56Z rwatson
* $NetBSD: nfsm_subs.h,v 1.4 2016/12/13 22:52:46 pgoyette Exp $
*/

#ifndef _NFS_NFSM_SUBS_H_
#define _NFS_NFSM_SUBS_H_


/*
* These macros do strange and peculiar things to mbuf chains for
* the assistance of the nfs code. To attempt to use them for any
* other purpose will be dangerous. (they make weird assumptions)
*/

#ifndef APPLE
/*
* First define what the actual subs. return
*/
#define NFSM_DATAP(m, s)        (m)->m_data += (s)

/*
* Now for the macros that do the simple stuff and call the functions
* for the hard stuff.
* They use fields in struct nfsrv_descript to handle the mbuf queues.
* Replace most of the macro with an inline function, to minimize
* the machine code. The inline functions in lower case can be called
* directly, bypassing the macro.
*/
static __inline void *
nfsm_build(struct nfsrv_descript *nd, int siz)
{
       void *retp;
       struct mbuf *mb2;

       if (siz > M_TRAILINGSPACE(nd->nd_mb)) {
               NFSMCLGET(mb2, M_NOWAIT);
               if (siz > MLEN)
                       panic("build > MLEN");
               mbuf_setlen(mb2, 0);
               nd->nd_bpos = NFSMTOD(mb2, char *);
               nd->nd_mb->m_next = mb2;
               nd->nd_mb = mb2;
       }
       retp = (void *)(nd->nd_bpos);
       nd->nd_mb->m_len += siz;
       nd->nd_bpos += siz;
       return (retp);
}

#define NFSM_BUILD(a, c, s)     ((a) = (c)nfsm_build(nd, (s)))

static __inline void *
nfsm_dissect(struct nfsrv_descript *nd, int siz)
{
       int tt1;
       void *retp;

       tt1 = NFSMTOD(nd->nd_md, char *) + nd->nd_md->m_len - nd->nd_dpos;
       if (tt1 >= siz) {
               retp = (void *)nd->nd_dpos;
               nd->nd_dpos += siz;
       } else {
               retp = nfsm_dissct(nd, siz, M_WAITOK);
       }
       return (retp);
}

static __inline void *
nfsm_dissect_nonblock(struct nfsrv_descript *nd, int siz)
{
       int tt1;
       void *retp;

       tt1 = NFSMTOD(nd->nd_md, char *) + nd->nd_md->m_len - nd->nd_dpos;
       if (tt1 >= siz) {
               retp = (void *)nd->nd_dpos;
               nd->nd_dpos += siz;
       } else {
               retp = nfsm_dissct(nd, siz, M_NOWAIT);
       }
       return (retp);
}

#define NFSM_DISSECT(a, c, s)                                           \
       do {                                                            \
               (a) = (c)nfsm_dissect(nd, (s));                         \
               if ((a) == NULL) {                                      \
                       error = EBADRPC;                                \
                       goto nfsmout;                                   \
               }                                                       \
       } while (0)

#define NFSM_DISSECT_NONBLOCK(a, c, s)                                  \
       do {                                                            \
               (a) = (c)nfsm_dissect_nonblock(nd, (s));                \
               if ((a) == NULL) {                                      \
                       error = EBADRPC;                                \
                       goto nfsmout;                                   \
               }                                                       \
       } while (0)
#endif  /* !APPLE */

#define NFSM_STRSIZ(s, m)                                               \
       do {                                                            \
               tl = (u_int32_t *)nfsm_dissect(nd, NFSX_UNSIGNED);      \
               if (!tl || ((s) = fxdr_unsigned(int32_t, *tl)) > (m)) { \
                       error = EBADRPC;                                \
                       goto nfsmout;                                   \
               }                                                       \
       } while (0)

#define NFSM_RNDUP(a)   (((a)+3)&(~0x3))

#endif  /* _NFS_NFSM_SUBS_H_ */