Dr. David Alan Gilbert, le jeu. 09 août 2018 12:32:05 +0100, a ecrit:
> > |--datasize---->|---m_len------->
> > |----------m_size------------------------------>
> > |----M_ROOM-------------------->
> > |-M_FREEROOM-->
> >
> > ^ ^ ^
> > m_dat m_data end of buffer
> >
> > ("datasize" is a bit misnamed, as it's "size of the leading
> > gap between the start of the buffer and the data"; "gapsize"
> > would be more helpful.)
> >
> > Anyway, we allocate size + datasize, and
> > m_size == datasize + M_ROOM. We know that size >= M_ROOM,
> > so the allocated buffer must be at least m_size big.
>
> Ah OK, thanks.
> (That ascii art could do with being in a comment somewhere!)
Indeed. Peter, maybe your Signed-off-by on this? :)
Samuel
commit 4be85a1eeb6b19e91491e689d4d0d054030cbb49
Author: Peter Maydell <[email protected]>
Date: Thu Aug 9 23:52:59 2018 +0200
slirp: document mbuf pointers and sizes
Signed-off-by: Samuel Thibault <[email protected]>
diff --git a/slirp/mbuf.h b/slirp/mbuf.h
index 33b84485d6..a5bb3f9e66 100644
--- a/slirp/mbuf.h
+++ b/slirp/mbuf.h
@@ -47,6 +47,16 @@
* free the m_ext. This is inefficient memory-wise, but who cares.
*/
+/*
+ * |--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
*/
