/*
 * Copyright (c) 2000, 2001 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.
 * 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.
 *
 * $FreeBSD: src/sys/kern/subr_mchain.c,v 1.2.2.2 2002/04/13 12:46:40 bp Exp $
 */


#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/endian.h>
#include <sys/errno.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/module.h>
#include <sys/uio.h>

#include <sys/mchain.h>

MODULE_VERSION(libmchain, 1);

#define MBERROR(format, ...) kprintf("%s(%d): "format, __func__ , \
                                    __LINE__ , ## __VA_ARGS__)

#define MBPANIC(format, ...) kprintf("%s(%d): "format, __func__ , \
                                    __LINE__ , ## __VA_ARGS__)

/*
 * Various helper functions
 */
int
m_fixhdr(struct mbuf *m0)
{
        struct mbuf *m = m0;
        int len = 0;

        while (m) {
                len += m->m_len;
                m = m->m_next;
        }
        m0->m_pkthdr.len = len;
        return len;
}

int
mb_init(struct mbchain *mbp)
{
        struct mbuf *m;

        m = m_gethdr(M_WAITOK, MT_DATA);
        m->m_pkthdr.rcvif = NULL;
        m->m_len = 0;
        mb_initm(mbp, m);
        return 0;
}

void
mb_initm(struct mbchain *mbp, struct mbuf *m)
{
        bzero(mbp, sizeof(*mbp));
        mbp->mb_top = mbp->mb_cur = m;
        mbp->mb_mleft = M_TRAILINGSPACE(m);
}

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

struct mbuf *
mb_detach(struct mbchain *mbp)
{
        struct mbuf *m;

        m = mbp->mb_top;
        mbp->mb_top = NULL;
        return m;
}

int
mb_fixhdr(struct mbchain *mbp)
{
        return mbp->mb_top->m_pkthdr.len = m_fixhdr(mbp->mb_top);
}

/*
 * 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.
 * Note: size should be <= MLEN
 */
caddr_t
mb_reserve(struct mbchain *mbp, int size)
{
        struct mbuf *m, *mn;
        caddr_t bpos;

        if (size > MLEN)
                panic("mb_reserve: size = %d", size);
        m = mbp->mb_cur;
        if (mbp->mb_mleft < size) {
                mn = m_get(M_WAITOK, MT_DATA);
                mbp->mb_cur = m->m_next = mn;
                m = mn;
                m->m_len = 0;
                mbp->mb_mleft = M_TRAILINGSPACE(m);
        }
        mbp->mb_mleft -= size;
        mbp->mb_count += size;
        bpos = mtod(m, caddr_t) + m->m_len;
        m->m_len += size;
        return bpos;
}

int
mb_put_uint8(struct mbchain *mbp, u_int8_t x)
{
        return mb_put_mem(mbp, (caddr_t)&x, sizeof(x), MB_MSYSTEM);
}

int
mb_put_uint16be(struct mbchain *mbp, u_int16_t x)
{
        x = htobe16(x);
        return mb_put_mem(mbp, (caddr_t)&x, sizeof(x), MB_MSYSTEM);
}

int
mb_put_uint16le(struct mbchain *mbp, u_int16_t x)
{
        x = htole16(x);
        return mb_put_mem(mbp, (caddr_t)&x, sizeof(x), MB_MSYSTEM);
}

int
mb_put_uint32be(struct mbchain *mbp, u_int32_t x)
{
        x = htobe32(x);
        return mb_put_mem(mbp, (caddr_t)&x, sizeof(x), MB_MSYSTEM);
}

int
mb_put_uint32le(struct mbchain *mbp, u_int32_t x)
{
        x = htole32(x);
        return mb_put_mem(mbp, (caddr_t)&x, sizeof(x), MB_MSYSTEM);
}

int
mb_put_int64be(struct mbchain *mbp, int64_t x)
{
        x = htobe64(x);
        return mb_put_mem(mbp, (caddr_t)&x, sizeof(x), MB_MSYSTEM);
}

int
mb_put_int64le(struct mbchain *mbp, int64_t x)
{
        x = htole64(x);
        return mb_put_mem(mbp, (caddr_t)&x, sizeof(x), MB_MSYSTEM);
}

int
mb_put_mem(struct mbchain *mbp, c_caddr_t source, int size, int type)
{
        struct mbuf *m;
        caddr_t dst;
        c_caddr_t src;
        int error, mleft, count;
        size_t cplen, srclen, dstlen;

        m = mbp->mb_cur;
        mleft = mbp->mb_mleft;

        while (size > 0) {
                if (mleft == 0) {
                        if (m->m_next == NULL)
                                m->m_next = m_getc(size, M_WAITOK, MT_DATA);
                        m = m->m_next;
                        mleft = M_TRAILINGSPACE(m);
                        continue;
                }
                cplen = mleft > size ? size : mleft;
                srclen = dstlen = cplen;
                dst = mtod(m, caddr_t) + m->m_len;
                switch (type) {
                    case MB_MCUSTOM:
                        srclen = size;
                        dstlen = mleft;
                        error = mbp->mb_copy(mbp, source, dst, &srclen, &dstlen);
                        if (error)
                                return error;
                        break;
                    case MB_MINLINE:
                        for (src = source, count = cplen; count; count--)
                                *dst++ = *src++;
                        break;
                    case MB_MSYSTEM:
                        bcopy(source, dst, cplen);
                        break;
                    case MB_MUSER:
                        error = copyin(source, dst, cplen);
                        if (error)
                                return error;
                        break;
                    case MB_MZERO:
                        bzero(dst, cplen);
                        break;
                }
                size -= srclen;
                source += srclen;
                m->m_len += dstlen;
                mleft -= dstlen;
                mbp->mb_count += dstlen;
        }
        mbp->mb_cur = m;
        mbp->mb_mleft = mleft;
        return 0;
}

int
mb_put_mbuf(struct mbchain *mbp, struct mbuf *m)
{
        mbp->mb_cur->m_next = m;
        while (m) {
                mbp->mb_count += m->m_len;
                if (m->m_next == NULL)
                        break;
                m = m->m_next;
        }
        mbp->mb_mleft = M_TRAILINGSPACE(m);
        mbp->mb_cur = m;
        return 0;
}

/*
 * copies a uio scatter/gather list to an mbuf chain.
 */
int
mb_put_uio(struct mbchain *mbp, struct uio *uiop, int size)
{
        long left;
        int mtype, error;

        mtype = (uiop->uio_segflg == UIO_SYSSPACE) ? MB_MSYSTEM : MB_MUSER;

        while (size > 0 && uiop->uio_resid) {
                if (uiop->uio_iovcnt <= 0 || uiop->uio_iov == NULL)
                        return EFBIG;
                left = uiop->uio_iov->iov_len;
                if (left == 0) {
                        uiop->uio_iov++;
                        uiop->uio_iovcnt--;
                        continue;
                }
                if (left > size)
                        left = size;
                error = mb_put_mem(mbp, uiop->uio_iov->iov_base, left, mtype);
                if (error)
                        return error;
                uiop->uio_offset += left;
                uiop->uio_resid -= left;
                uiop->uio_iov->iov_base =
                    (char *)uiop->uio_iov->iov_base + left;
                uiop->uio_iov->iov_len -= left;
                size -= left;
        }
        return 0;
}

/*
 * Routines for fetching data from an mbuf chain
 */
int
md_init(struct mdchain *mdp)
{
        struct mbuf *m;

        m = m_gethdr(M_WAITOK, MT_DATA);
        m->m_pkthdr.rcvif = NULL;
        m->m_len = 0;
        md_initm(mdp, m);
        return 0;
}

void
md_initm(struct mdchain *mdp, struct mbuf *m)
{
        bzero(mdp, sizeof(*mdp));
        mdp->md_top = mdp->md_cur = m;
        mdp->md_pos = mtod(m, u_char*);
}

void
md_done(struct mdchain *mdp)
{
        if (mdp->md_top) {
                m_freem(mdp->md_top);
                mdp->md_top = NULL;
        }
}

/*
 * Append a separate mbuf chain. It is caller responsibility to prevent
 * multiple calls to fetch/record routines.
 */
void
md_append_record(struct mdchain *mdp, struct mbuf *top)
{
        struct mbuf *m;

        if (mdp->md_top == NULL) {
                md_initm(mdp, top);
                return;
        }
        m = mdp->md_top;
        while (m->m_nextpkt)
                m = m->m_nextpkt;
        m->m_nextpkt = top;
        top->m_nextpkt = NULL;
        return;
}

/*
 * Put next record in place of existing
 */
int
md_next_record(struct mdchain *mdp)
{
        struct mbuf *m;

        if (mdp->md_top == NULL)
                return ENOENT;
        m = mdp->md_top->m_nextpkt;
        md_done(mdp);
        if (m == NULL)
                return ENOENT;
        md_initm(mdp, m);
        return 0;
}

int
md_get_uint8(struct mdchain *mdp, u_int8_t *x)
{
        return md_get_mem(mdp, x, 1, MB_MINLINE);
}

int
md_get_uint16(struct mdchain *mdp, u_int16_t *x)
{
        return md_get_mem(mdp, (caddr_t)x, 2, MB_MINLINE);
}

int
md_get_uint16le(struct mdchain *mdp, u_int16_t *x)
{
        u_int16_t v;
        int error = md_get_uint16(mdp, &v);

        if (x != NULL)
                *x = le16toh(v);
        return error;
}

int
md_get_uint16be(struct mdchain *mdp, u_int16_t *x) {
        u_int16_t v;
        int error = md_get_uint16(mdp, &v);

        if (x != NULL)
                *x = be16toh(v);
        return error;
}

int
md_get_uint32(struct mdchain *mdp, u_int32_t *x)
{
        return md_get_mem(mdp, (caddr_t)x, 4, MB_MINLINE);
}

int
md_get_uint32be(struct mdchain *mdp, u_int32_t *x)
{
        u_int32_t v;
        int error;

        error = md_get_uint32(mdp, &v);
        if (x != NULL)
                *x = be32toh(v);
        return error;
}

int
md_get_uint32le(struct mdchain *mdp, u_int32_t *x)
{
        u_int32_t v;
        int error;

        error = md_get_uint32(mdp, &v);
        if (x != NULL)
                *x = le32toh(v);
        return error;
}

int
md_get_int64(struct mdchain *mdp, int64_t *x)
{
        return md_get_mem(mdp, (caddr_t)x, 8, MB_MINLINE);
}

int
md_get_int64be(struct mdchain *mdp, int64_t *x)
{
        int64_t v;
        int error;

        error = md_get_int64(mdp, &v);
        if (x != NULL)
                *x = be64toh(v);
        return error;
}

int
md_get_int64le(struct mdchain *mdp, int64_t *x)
{
        int64_t v;
        int error;

        error = md_get_int64(mdp, &v);
        if (x != NULL)
                *x = le64toh(v);
        return error;
}

int
md_get_mem(struct mdchain *mdp, caddr_t target, int size, int type)
{
        struct mbuf *m = mdp->md_cur;
        int error;
        u_int count;
        u_char *s;

        while (size > 0) {
                if (m == NULL) {
                        MBERROR("incomplete copy\n");
                        return EBADRPC;
                }
                s = mdp->md_pos;
                count = mtod(m, u_char*) + m->m_len - s;
                if (count == 0) {
                        mdp->md_cur = m = m->m_next;
                        if (m)
                                s = mdp->md_pos = mtod(m, caddr_t);
                        continue;
                }
                if (count > size)
                        count = size;
                size -= count;
                mdp->md_pos += count;
                if (target == NULL)
                        continue;
                switch (type) {
                    case MB_MUSER:
                        error = copyout(s, target, count);
                        if (error)
                                return error;
                        break;
                    case MB_MSYSTEM:
                        bcopy(s, target, count);
                        break;
                    case MB_MINLINE:
                        while (count--)
                                *target++ = *s++;
                        continue;
                }
                target += count;
        }
        return 0;
}

int
md_get_mbuf(struct mdchain *mdp, int size, struct mbuf **ret)
{
        struct mbuf *m = mdp->md_cur, *rm;

        rm = m_copym(m, mdp->md_pos - mtod(m, u_char*), size, M_WAITOK);
        if (rm == NULL)
                return EBADRPC;
        md_get_mem(mdp, NULL, size, MB_MZERO);
        *ret = rm;
        return 0;
}

int
md_get_uio(struct mdchain *mdp, struct uio *uiop, int size)
{
        char *uiocp;
        long left;
        int mtype, error;

        mtype = (uiop->uio_segflg == UIO_SYSSPACE) ? MB_MSYSTEM : MB_MUSER;
        while (size > 0 && uiop->uio_resid) {
                if (uiop->uio_iovcnt <= 0 || uiop->uio_iov == NULL)
                        return EFBIG;
                left = uiop->uio_iov->iov_len;
                if (left == 0) {
                        uiop->uio_iov++;
                        uiop->uio_iovcnt--;
                        continue;
                }
                uiocp = uiop->uio_iov->iov_base;
                if (left > size)
                        left = size;
                error = md_get_mem(mdp, uiocp, left, mtype);
                if (error)
                        return error;
                uiop->uio_offset += left;
                uiop->uio_resid -= left;
                uiop->uio_iov->iov_base =
                    (char *)uiop->uio_iov->iov_base + left;
                uiop->uio_iov->iov_len -= left;
                size -= left;
        }
        return 0;
}