/*
 * Copyright (c) 2000, Boris Popov
 * All rights reserved.
 *
 * 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.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *    This product includes software developed by Boris Popov.
 * 4. Neither the name of the author nor the names of any co-contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
 *
 * $Id: mbuf.c,v 1.3 2004/12/13 00:25:22 lindak Exp $
 */

/*
 * Copyright (c) 2008, 2010, Oracle and/or its affiliates. All rights reserved.
 */

#include <sys/types.h>
#include <ctype.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <strings.h>
#include <libintl.h>
#include <assert.h>

#include <netsmb/smb_lib.h>
#include <netsmb/mchain.h>

#include "private.h"
#include "charsets.h"

/*
 * Note: Leaving a little space (8 bytes) between the
 * mbuf header and the start of the data so we can
 * prepend a NetBIOS header in that space.
 */
#define M_ALIGNFACTOR   (sizeof (long))
#define M_ALIGN(len)    (((len) + M_ALIGNFACTOR - 1) & ~(M_ALIGNFACTOR - 1))
#define M_BASESIZE      (sizeof (struct mbuf) + 8)
#define M_MINSIZE       (1024 - M_BASESIZE)
#define M_TOP(m)        ((char *)(m) + M_BASESIZE)
#define M_TRAILINGSPACE(m) ((m)->m_maxlen - (m)->m_len)

int
m_get(int len, struct mbuf **mpp)
{
        struct mbuf *m;

        assert(len < 0x100000); /* sanity */

        len = M_ALIGN(len);
        if (len < M_MINSIZE)
                len = M_MINSIZE;
        m = malloc(M_BASESIZE + len);
        if (m == NULL)
                return (ENOMEM);
        bzero(m, M_BASESIZE + len);
        m->m_maxlen = len;
        m->m_data = M_TOP(m);
        *mpp = m;
        return (0);
}

static void
m_free(struct mbuf *m)
{
        free(m);
}

void
m_freem(struct mbuf *m0)
{
        struct mbuf *m;

        while (m0) {
                m = m0->m_next;
                m_free(m0);
                m0 = m;
        }
}

size_t
m_totlen(struct mbuf *m0)
{
        struct mbuf *m = m0;
        int len = 0;

        while (m) {
                len += m->m_len;
                m = m->m_next;
        }
        return (len);
}

int
m_lineup(struct mbuf *m0, struct mbuf **mpp)
{
        struct mbuf *nm, *m;
        char *dp;
        size_t len, totlen;
        int error;

        if (m0->m_next == NULL) {
                *mpp = m0;
                return (0);
        }
        totlen = m_totlen(m0);
        if ((error = m_get(totlen, &nm)) != 0)
                return (error);
        dp = mtod(nm, char *);
        while (m0) {
                len = m0->m_len;
                bcopy(m0->m_data, dp, len);
                dp += len;
                m = m0->m_next;
                m_free(m0);
                m0 = m;
        }
        nm->m_len = totlen;
        *mpp = nm;
        return (0);
}

int
mb_init(struct mbdata *mbp)
{
        return (mb_init_sz(mbp, M_MINSIZE));
}

int
mb_init_sz(struct mbdata *mbp, int size)
{
        struct mbuf *m;
        int error;

        if ((error = m_get(size, &m)) != 0)
                return (error);
        mb_initm(mbp, m);
        return (0);
}

void
mb_initm(struct mbdata *mbp, struct mbuf *m)
{
        bzero(mbp, sizeof (*mbp));
        mbp->mb_top = mbp->mb_cur = m;
        mbp->mb_pos = mtod(m, char *);
}

void
mb_done(struct mbdata *mbp)
{
        if (mbp->mb_top) {
                m_freem(mbp->mb_top);
                mbp->mb_top = NULL;
        }
}

int
m_getm(struct mbuf *top, int len, struct mbuf **mpp)
{
        struct mbuf *m, *mp;
        int  error, ts;

        for (mp = top; ; mp = mp->m_next) {
                ts = M_TRAILINGSPACE(mp);
                if (len <= ts)
                        goto out;
                len -= ts;
                if (mp->m_next == NULL)
                        break;

        }
        if (len > 0) {
                if ((error = m_get(len, &m)) != 0)
                        return (error);
                mp->m_next = m;
        }
out:
        *mpp = top;
        return (0);
}

/*
 * Routines to put data in a buffer
 */

void *
mb_reserve(mbchain_t *mbp, int size)
{
        char *p;

        if (mb_fit(mbp, size, &p) != 0)
                return (NULL);

        return (p);
}

/*
 * Check if object of size 'size' fit to the current position and
 * allocate new mbuf if not. Advance pointers and increase length of mbuf(s).
 * Return pointer to the object placeholder or NULL if any error occured.
 */
int
mb_fit(mbchain_t *mbp, int size, char **pp)
{
        struct mbuf *m, *mn;
        int error;

        m = mbp->mb_cur;
        if (M_TRAILINGSPACE(m) < (int)size) {
                if ((error = m_get(size, &mn)) != 0)
                        return (error);
                mbp->mb_pos = mtod(mn, char *);
                mbp->mb_cur = m->m_next = mn;
                m = mn;
        }
        m->m_len += size;
        *pp = mbp->mb_pos;
        mbp->mb_pos += size;
        mbp->mb_count += size;
        return (0);
}

int
mb_put_uint8(mbchain_t *mbp, uint8_t x)
{
        uint8_t y = x;
        return (mb_put_mem(mbp, &y, sizeof (y), MB_MINLINE));
}

int
mb_put_uint16be(mbchain_t *mbp, uint16_t x)
{
        uint16_t y = htobes(x);
        return (mb_put_mem(mbp, &y, sizeof (y), MB_MINLINE));
}

int
mb_put_uint16le(mbchain_t *mbp, uint16_t x)
{
        uint16_t y = htoles(x);
        return (mb_put_mem(mbp, &y, sizeof (y), MB_MINLINE));
}

int
mb_put_uint32be(mbchain_t *mbp, uint32_t x)
{
        uint32_t y = htobel(x);
        return (mb_put_mem(mbp, &y, sizeof (y), MB_MINLINE));
}

int
mb_put_uint32le(mbchain_t *mbp, uint32_t x)
{
        uint32_t y = htolel(x);
        return (mb_put_mem(mbp, &y, sizeof (y), MB_MINLINE));
}

int
mb_put_uint64be(mbchain_t *mbp, uint64_t x)
{
        uint64_t y = htobeq(x);
        return (mb_put_mem(mbp, &y, sizeof (y), MB_MINLINE));
}

int
mb_put_uint64le(mbchain_t *mbp, uint64_t x)
{
        uint64_t y = htoleq(x);
        return (mb_put_mem(mbp, &y, sizeof (y), MB_MINLINE));
}

/* ARGSUSED */
int
mb_put_mem(mbchain_t *mbp, const void *vmem, int size, int type)
{
        struct mbuf *m;
        const char *src;
        char  *dst;
        size_t cplen;
        int error;

        if (size == 0)
                return (0);

        src = vmem;
        m = mbp->mb_cur;
        if ((error = m_getm(m, size, &m)) != 0)
                return (error);
        while (size > 0) {
                cplen = M_TRAILINGSPACE(m);
                if (cplen == 0) {
                        m = m->m_next;
                        continue;
                }
                if (cplen > size)
                        cplen = size;
                dst = mtod(m, char *) + m->m_len;
                if (src) {
                        bcopy(src, dst, cplen);
                        src += cplen;
                } else
                        bzero(dst, cplen);
                size -= cplen;
                m->m_len += cplen;
                mbp->mb_count += cplen;
        }
        mbp->mb_pos = mtod(m, char *) + m->m_len;
        mbp->mb_cur = m;
        return (0);
}

/*
 * Append another mbuf to the mbuf chain.
 * If what we're appending is smaller than
 * the current trailing space, just copy.
 * This always consumes the passed mbuf.
 */
int
mb_put_mbuf(mbchain_t *mbp, struct mbuf *m)
{
        struct mbuf *cm = mbp->mb_cur;
        int ts = M_TRAILINGSPACE(cm);

        if (m->m_next == NULL && m->m_len <= ts) {
                /* just copy */
                mb_put_mem(mbp, m->m_data, m->m_len, MB_MSYSTEM);
                m_freem(m);
                return (0);
        }

        cm->m_next = m;
        while (m) {
                mbp->mb_count += m->m_len;
                if (m->m_next == NULL)
                        break;
                m = m->m_next;
        }
        mbp->mb_pos = mtod(m, char *) + m->m_len;
        mbp->mb_cur = m;
        return (0);
}

/*
 * Convenience function to put an OEM or Unicode string,
 * null terminated, and aligned if necessary.
 */
int
mb_put_string(mbchain_t *mbp, const char *s, int uc)
{
        int err;

        if (uc) {
                /* Put Unicode.  align(2) first. */
                if (mbp->mb_count & 1)
                        mb_put_uint8(mbp, 0);
                err = mb_put_ustring(mbp, s);
        } else {
                /* Put ASCII (really OEM) */
                err = mb_put_astring(mbp, s);
        }

        return (err);
}

/*
 * Put an ASCII string (really OEM), given a UTF-8 string.
 */
int
mb_put_astring(mbchain_t *mbp, const char *s)
{
        char *abuf;
        int err, len;

        abuf = convert_utf8_to_wincs(s);
        if (abuf == NULL)
                return (ENOMEM);
        len = strlen(abuf) + 1;
        err = mb_put_mem(mbp, abuf, len, MB_MSYSTEM);
        free(abuf);
        return (err);
}

/*
 * Put UCS-2LE, given a UTF-8 string.
 */
int
mb_put_ustring(mbchain_t *mbp, const char *s)
{
        uint16_t *ubuf;
        int err, len;

        ubuf = convert_utf8_to_leunicode(s);
        if (ubuf == NULL)
                return (ENOMEM);
        len = 2 * (unicode_strlen(ubuf) + 1);
        err = mb_put_mem(mbp, ubuf, len, MB_MSYSTEM);
        free(ubuf);
        return (err);
}

/*
 * Routines for fetching data from an mbuf chain
 */
#define mb_left(m, p)   (mtod(m, char *) + (m)->m_len - (p))

int
md_get_uint8(mdchain_t *mbp, uint8_t *x)
{
        return (md_get_mem(mbp, x, 1, MB_MINLINE));
}

int
md_get_uint16le(mdchain_t *mbp, uint16_t *x)
{
        uint16_t v;
        int err;

        if ((err = md_get_mem(mbp, &v, sizeof (v), MB_MINLINE)) != 0)
                return (err);
        if (x != NULL)
                *x = letohs(v);
        return (0);
}

int
md_get_uint16be(mdchain_t *mbp, uint16_t *x) {
        uint16_t v;
        int err;

        if ((err = md_get_mem(mbp, &v, sizeof (v), MB_MINLINE)) != 0)
                return (err);
        if (x != NULL)
                *x = betohs(v);
        return (0);
}

int
md_get_uint32be(mdchain_t *mbp, uint32_t *x)
{
        uint32_t v;
        int err;

        if ((err = md_get_mem(mbp, &v, sizeof (v), MB_MINLINE)) != 0)
                return (err);
        if (x != NULL)
                *x = betohl(v);
        return (0);
}

int
md_get_uint32le(mdchain_t *mbp, uint32_t *x)
{
        uint32_t v;
        int err;

        if ((err = md_get_mem(mbp, &v, sizeof (v), MB_MINLINE)) != 0)
                return (err);
        if (x != NULL)
                *x = letohl(v);
        return (0);
}

int
md_get_uint64be(mdchain_t *mbp, uint64_t *x)
{
        uint64_t v;
        int err;

        if ((err = md_get_mem(mbp, &v, sizeof (v), MB_MINLINE)) != 0)
                return (err);
        if (x != NULL)
                *x = betohq(v);
        return (0);
}

int
md_get_uint64le(mdchain_t *mbp, uint64_t *x)
{
        uint64_t v;
        int err;

        if ((err = md_get_mem(mbp, &v, sizeof (v), MB_MINLINE)) != 0)
                return (err);
        if (x != NULL)
                *x = letohq(v);
        return (0);
}

/* ARGSUSED */
int
md_get_mem(mdchain_t *mbp, void *vmem, int size, int type)
{
        struct mbuf *m = mbp->mb_cur;
        char *dst = vmem;
        uint_t count;

        while (size > 0) {
                if (m == NULL) {
                        /* DPRINT("incomplete copy"); */
                        return (EBADRPC);
                }
                count = mb_left(m, mbp->mb_pos);
                if (count == 0) {
                        mbp->mb_cur = m = m->m_next;
                        if (m)
                                mbp->mb_pos = mtod(m, char *);
                        continue;
                }
                if (count > size)
                        count = size;
                size -= count;
                if (dst) {
                        if (count == 1) {
                                *dst++ = *mbp->mb_pos;
                        } else {
                                bcopy(mbp->mb_pos, dst, count);
                                dst += count;
                        }
                }
                mbp->mb_pos += count;
        }
        return (0);
}

/*
 * Get the next SIZE bytes as a separate mblk.
 * Nothing fancy here - just copy.
 */
int
md_get_mbuf(mdchain_t *mbp, int size, mbuf_t **ret)
{
        mbuf_t *m;
        int err;

        err = m_get(size, &m);
        if (err)
                return (err);

        err = md_get_mem(mbp, m->m_data, size, MB_MSYSTEM);
        if (err) {
                m_freem(m);
                return (err);
        }
        m->m_len = size;
        *ret = m;

        return (0);
}

/*
 * Get a string from the mbuf chain,
 * either Unicode or OEM chars.
 */
int
md_get_string(mdchain_t *mbp, char **str_pp, int uc)
{
        int err;

        if (uc)
                err = md_get_ustring(mbp, str_pp);
        else
                err = md_get_astring(mbp, str_pp);
        return (err);
}

/*
 * Get an ASCII (really OEM) string from the mbuf chain
 * and convert it to UTF-8
 *
 * Similar to md_get_ustring below.
 */
int
md_get_astring(mdchain_t *real_mbp, char **str_pp)
{
        mdchain_t tmp_mb, *mbp;
        char *tstr, *ostr;
        int err, i, slen;
        uint8_t ch;

        /*
         * First, figure out the string length.
         * Use a copy of the real_mbp so we don't
         * actually consume it here, then search for
         * the null (or end of data).
         */
        bcopy(real_mbp, &tmp_mb, sizeof (tmp_mb));
        mbp = &tmp_mb;
        slen = 0;
        for (;;) {
                err = md_get_uint8(mbp, &ch);
                if (err)
                        break;
                if (ch == 0)
                        break;
                slen++;
        }

        /*
         * Now read the (OEM) string for real.
         * No need to re-check errors.
         */
        tstr = malloc(slen + 1);
        if (tstr == NULL)
                return (ENOMEM);
        mbp = real_mbp;
        for (i = 0; i < slen; i++) {
                md_get_uint8(mbp, &ch);
                tstr[i] = ch;
        }
        tstr[i] = 0;
        md_get_uint8(mbp, NULL);

        /*
         * Convert OEM to UTF-8
         */
        ostr = convert_wincs_to_utf8(tstr);
        free(tstr);
        if (ostr == NULL)
                return (ENOMEM);

        *str_pp = ostr;
        return (0);
}

/*
 * Get a UCS-2LE string from the mbuf chain, and
 * convert it to UTF-8.
 *
 * Similar to md_get_astring above.
 */
int
md_get_ustring(mdchain_t *real_mbp, char **str_pp)
{
        mdchain_t tmp_mb, *mbp;
        uint16_t *tstr;
        char *ostr;
        int err, i, slen;
        uint16_t ch;

        /*
         * First, align(2) on the real_mbp
         */
        if (((uintptr_t)real_mbp->mb_pos) & 1)
                md_get_uint8(real_mbp, NULL);

        /*
         * Next, figure out the string length.
         * Use a copy of the real_mbp so we don't
         * actually consume it here, then search for
         * the null (or end of data).
         */
        bcopy(real_mbp, &tmp_mb, sizeof (tmp_mb));
        mbp = &tmp_mb;
        slen = 0;
        for (;;) {
                err = md_get_uint16le(mbp, &ch);
                if (err)
                        break;
                if (ch == 0)
                        break;
                slen++;
        }

        /*
         * Now read the (UCS-2) string for real.
         * No need to re-check errors.  Note:
         * This puts the UCS-2 in NATIVE order!
         */
        tstr = calloc(slen + 1, 2);
        if (tstr == NULL)
                return (ENOMEM);
        mbp = real_mbp;
        for (i = 0; i < slen; i++) {
                md_get_uint16le(mbp, &ch);
                tstr[i] = ch;
        }
        tstr[i] = 0;
        md_get_uint16le(mbp, NULL);

        /*
         * Convert UCS-2 (native!) to UTF-8
         */
        ostr = convert_unicode_to_utf8(tstr);
        free(tstr);
        if (ostr == NULL)
                return (ENOMEM);

        *str_pp = ostr;
        return (0);
}