/*      $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_ */