Commit 632dd719 authored by Peter Maydell's avatar Peter Maydell Committed by Samuel Thibault
Browse files

slirp: document mbuf pointers and sizes 



and fix confusing datasize name into gapsize in m_inc.

Signed-off-by: default avatarPeter Maydell <peter.maydell@linaro.org>
Signed-off-by: default avatarSamuel Thibault <samuel.thibault@ens-lyon.org>
parent 3c2d3042

slirp/mbuf.c

+7 −7
Original line number Diff line number Diff line
@@ -151,7 +151,7 @@ m_cat(struct mbuf *m, struct mbuf *n) 
void

m_inc(struct mbuf *m, int size)

{

    int datasize;

    int gapsize;



    /* some compilers throw up on gotos.  This one we can fake. */

    if (M_ROOM(m) > size) {
@@ -159,17 +159,17 @@ m_inc(struct mbuf *m, int size) 
    }



    if (m->m_flags & M_EXT) {

        datasize = m->m_data - m->m_ext;

        m->m_ext = g_realloc(m->m_ext, size + datasize);

        gapsize = m->m_data - m->m_ext;

        m->m_ext = g_realloc(m->m_ext, size + gapsize);

    } else {

        datasize = m->m_data - m->m_dat;

        m->m_ext = g_malloc(size + datasize);

        gapsize = m->m_data - m->m_dat;

        m->m_ext = g_malloc(size + gapsize);

        memcpy(m->m_ext, m->m_dat, m->m_size);

        m->m_flags |= M_EXT;

    }



    m->m_data = m->m_ext + datasize;

    m->m_size = size + datasize;

    m->m_data = m->m_ext + gapsize;

    m->m_size = size + gapsize;

}

slirp/mbuf.h

+13 −0
Original line number Diff line number Diff line
@@ -47,6 +47,19 @@ 
 * free the m_ext.  This is inefficient memory-wise, but who cares.

 */



/*

 * mbufs allow to have a gap between the start of the allocated buffer (m_ext if

 * M_EXT is set, m_dat otherwise) and the in-use data:

 *

 *  |--gapsize----->|---m_len------->

 *  |----------m_size------------------------------>

 *                  |----M_ROOM-------------------->

 *                                   |-M_FREEROOM-->

 *

 *  ^               ^                               ^

 *  m_dat/m_ext     m_data                          end of buffer

 */



/*

 * How much room is in the mbuf, from m_data to the end of the mbuf

 */