>--- sys/mbuf.h	2000/08/18 16:19:23	1.53
>+++ sys/mbuf.h	2000/11/13 21:48:11
>@@ -114,6 +114,10 @@
> 	int	mh_len;			/* amount of data in this mbuf */
> 	short	mh_type;		/* type of data in this mbuf */
> 	short	mh_flags;		/* flags; see below */
>+	union   {
>+		int mh_info;
>+		void *mh_infop;
>+	} mh_info;			/* link-layer specific info */
> };

	you may want to look at m->m_pkthdr.m_aux.  it can hold anything you
	want.

itojun