Archipelago » qemu

/*

 * Copyright (c) 1995 Danny Gasparovski.

 *

 * Please read the file COPYRIGHT for the

 * terms and conditions of the copyright.

 */

#include <slirp.h>

static void sbappendsb(struct sbuf *sb, struct mbuf *m);

void

sbfree(struct sbuf *sb)

{

        free(sb->sb_data);

}

void

sbdrop(struct sbuf *sb, int num)

{

        /*

         * We can only drop how much we have

         * This should never succeed

         */

        if(num > sb->sb_cc)

                num = sb->sb_cc;

        sb->sb_cc -= num;

        sb->sb_rptr += num;

        if(sb->sb_rptr >= sb->sb_data + sb->sb_datalen)

                sb->sb_rptr -= sb->sb_datalen;

}

void

sbreserve(struct sbuf *sb, int size)

{

        if (sb->sb_data) {

                /* Already alloced, realloc if necessary */

                if (sb->sb_datalen != size) {

                        sb->sb_wptr = sb->sb_rptr = sb->sb_data = (char *)realloc(sb->sb_data, size);

                        sb->sb_cc = 0;

                        if (sb->sb_wptr)

                           sb->sb_datalen = size;

                        else

                           sb->sb_datalen = 0;

                }

        } else {

                sb->sb_wptr = sb->sb_rptr = sb->sb_data = (char *)malloc(size);

                sb->sb_cc = 0;

                if (sb->sb_wptr)

                   sb->sb_datalen = size;

                else

                   sb->sb_datalen = 0;

        }

}

/*

 * Try and write() to the socket, whatever doesn't get written

 * append to the buffer... for a host with a fast net connection,

 * this prevents an unnecessary copy of the data

 * (the socket is non-blocking, so we won't hang)

 */

void

sbappend(struct socket *so, struct mbuf *m)

{

        int ret = 0;

        DEBUG_CALL("sbappend");

        DEBUG_ARG("so = %lx", (long)so);

        DEBUG_ARG("m = %lx", (long)m);

        DEBUG_ARG("m->m_len = %d", m->m_len);

        /* Shouldn't happen, but...  e.g. foreign host closes connection */

        if (m->m_len <= 0) {

                m_free(m);

                return;

        }

        /*

         * If there is urgent data, call sosendoob

         * if not all was sent, sowrite will take care of the rest

         * (The rest of this function is just an optimisation)

         */

        if (so->so_urgc) {

                sbappendsb(&so->so_rcv, m);

                m_free(m);

                sosendoob(so);

                return;

        }

        /*

         * We only write if there's nothing in the buffer,

         * ottherwise it'll arrive out of order, and hence corrupt

         */

        if (!so->so_rcv.sb_cc)

           ret = slirp_send(so, m->m_data, m->m_len, 0);

        if (ret <= 0) {

                /*

                 * Nothing was written

                 * It's possible that the socket has closed, but

                 * we don't need to check because if it has closed,

                 * it will be detected in the normal way by soread()

                 */

                sbappendsb(&so->so_rcv, m);

        } else if (ret != m->m_len) {

                /*

                 * Something was written, but not everything..

                 * sbappendsb the rest

                 */

                m->m_len -= ret;

                m->m_data += ret;

                sbappendsb(&so->so_rcv, m);

        } /* else */

        /* Whatever happened, we free the mbuf */

        m_free(m);

}

/*

 * Copy the data from m into sb

 * The caller is responsible to make sure there's enough room

 */

static void

sbappendsb(struct sbuf *sb, struct mbuf *m)

{

        int len, n,  nn;

        len = m->m_len;

        if (sb->sb_wptr < sb->sb_rptr) {

                n = sb->sb_rptr - sb->sb_wptr;

                if (n > len) n = len;

                memcpy(sb->sb_wptr, m->m_data, n);

        } else {

                /* Do the right edge first */

                n = sb->sb_data + sb->sb_datalen - sb->sb_wptr;

                if (n > len) n = len;

                memcpy(sb->sb_wptr, m->m_data, n);

                len -= n;

                if (len) {

                        /* Now the left edge */

                        nn = sb->sb_rptr - sb->sb_data;

                        if (nn > len) nn = len;

                        memcpy(sb->sb_data,m->m_data+n,nn);

                        n += nn;

                }

        }

        sb->sb_cc += n;

        sb->sb_wptr += n;

        if (sb->sb_wptr >= sb->sb_data + sb->sb_datalen)

                sb->sb_wptr -= sb->sb_datalen;

}

/*

 * Copy data from sbuf to a normal, straight buffer

 * Don't update the sbuf rptr, this will be

 * done in sbdrop when the data is acked

 */

void

sbcopy(struct sbuf *sb, int off, int len, char *to)

{

        char *from;

        from = sb->sb_rptr + off;

        if (from >= sb->sb_data + sb->sb_datalen)

                from -= sb->sb_datalen;

        if (from < sb->sb_wptr) {

                if (len > sb->sb_cc) len = sb->sb_cc;

                memcpy(to,from,len);

        } else {

                /* re-use off */

                off = (sb->sb_data + sb->sb_datalen) - from;

                if (off > len) off = len;

                memcpy(to,from,off);

                len -= off;

                if (len)

                   memcpy(to+off,sb->sb_data,len);

        }

}