diff --git a/slirp/mbuf.c b/slirp/mbuf.c
new file mode 100644
index 0000000..fa36d89
--- /dev/null
+++ b/slirp/mbuf.c
@@ -0,0 +1,245 @@
+/*
+ * Copyright (c) 1995 Danny Gasparovski
+ *
+ * Please read the file COPYRIGHT for the
+ * terms and conditions of the copyright.
+ */
+
+/*
+ * mbuf's in SLiRP are much simpler than the real mbufs in
+ * FreeBSD.  They are fixed size, determined by the MTU,
+ * so that one whole packet can fit.  Mbuf's cannot be
+ * chained together.  If there's more data than the mbuf
+ * could hold, an external malloced buffer is pointed to
+ * by m_ext (and the data pointers) and M_EXT is set in
+ * the flags
+ */
+
+#include <slirp.h>
+
+struct	mbuf *mbutl;
+char	*mclrefcnt;
+int mbuf_alloced = 0;
+struct mbuf m_freelist, m_usedlist;
+int mbuf_thresh = 30;
+int mbuf_max = 0;
+int msize;
+
+void
+m_init()
+{
+	m_freelist.m_next = m_freelist.m_prev = &m_freelist;
+	m_usedlist.m_next = m_usedlist.m_prev = &m_usedlist;
+	msize_init();
+}
+
+void
+msize_init()
+{
+	/*
+	 * Find a nice value for msize
+	 * XXX if_maxlinkhdr already in mtu
+	 */
+	msize = (if_mtu>if_mru?if_mtu:if_mru) + 
+			if_maxlinkhdr + sizeof(struct m_hdr ) + 6;
+}
+
+/*
+ * Get an mbuf from the free list, if there are none
+ * malloc one
+ * 
+ * Because fragmentation can occur if we alloc new mbufs and
+ * free old mbufs, we mark all mbufs above mbuf_thresh as M_DOFREE,
+ * which tells m_free to actually free() it
+ */
+struct mbuf *
+m_get()
+{
+	register struct mbuf *m;
+	int flags = 0;
+	
+	DEBUG_CALL("m_get");
+	
+	if (m_freelist.m_next == &m_freelist) {
+		m = (struct mbuf *)malloc(msize);
+		if (m == NULL) goto end_error;
+		mbuf_alloced++;
+		if (mbuf_alloced > mbuf_thresh)
+			flags = M_DOFREE;
+		if (mbuf_alloced > mbuf_max)
+			mbuf_max = mbuf_alloced;
+	} else {
+		m = m_freelist.m_next;
+		remque(m);
+	}
+	
+	/* Insert it in the used list */
+	insque(m,&m_usedlist);
+	m->m_flags = (flags | M_USEDLIST);
+	
+	/* Initialise it */
+	m->m_size = msize - sizeof(struct m_hdr);
+	m->m_data = m->m_dat;
+	m->m_len = 0;
+	m->m_nextpkt = 0;
+	m->m_prevpkt = 0;
+end_error:
+	DEBUG_ARG("m = %lx", (long )m);
+	return m;
+}
+
+void
+m_free(m)
+	struct mbuf *m;
+{
+	
+  DEBUG_CALL("m_free");
+  DEBUG_ARG("m = %lx", (long )m);
+	
+  if(m) {
+	/* Remove from m_usedlist */
+	if (m->m_flags & M_USEDLIST)
+	   remque(m);
+	
+	/* If it's M_EXT, free() it */
+	if (m->m_flags & M_EXT)
+	   free(m->m_ext);
+
+	/*
+	 * Either free() it or put it on the free list
+	 */
+	if (m->m_flags & M_DOFREE) {
+		free(m);
+		mbuf_alloced--;
+	} else if ((m->m_flags & M_FREELIST) == 0) {
+		insque(m,&m_freelist);
+		m->m_flags = M_FREELIST; /* Clobber other flags */
+	}
+  } /* if(m) */
+}
+
+/*
+ * Copy data from one mbuf to the end of
+ * the other.. if result is too big for one mbuf, malloc()
+ * an M_EXT data segment
+ */
+void
+m_cat(m, n)
+	register struct mbuf *m, *n;
+{
+	/*
+	 * If there's no room, realloc
+	 */
+	if (M_FREEROOM(m) < n->m_len)
+		m_inc(m,m->m_size+MINCSIZE);
+	
+	memcpy(m->m_data+m->m_len, n->m_data, n->m_len);
+	m->m_len += n->m_len;
+
+	m_free(n);
+}
+
+
+/* make m size bytes large */
+void
+m_inc(m, size)
+        struct mbuf *m;
+        int size;
+{
+	/* some compiles throw up on gotos.  This one we can fake. */
+        if(m->m_size>size) return;
+
+        if (m->m_flags & M_EXT) {
+	  /* datasize = m->m_data - m->m_ext; */
+	  m->m_ext = (char *)realloc(m->m_ext,size);
+/*		if (m->m_ext == NULL)
+ *			return (struct mbuf *)NULL;
+ */		
+	  /* m->m_data = m->m_ext + datasize; */
+        } else {
+	  int datasize;
+	  char *dat;
+	  datasize = m->m_data - m->m_dat;
+	  dat = (char *)malloc(size);
+/*		if (dat == NULL)
+ *			return (struct mbuf *)NULL;
+ */
+	  memcpy(dat, m->m_dat, m->m_size);
+	  
+	  m->m_ext = dat;
+	  m->m_data = m->m_ext + datasize;
+	  m->m_flags |= M_EXT;
+        }
+ 
+        m->m_size = size;
+
+}
+
+
+
+void
+m_adj(m, len)
+	struct mbuf *m;
+	int len;
+{
+	if (m == NULL)
+		return;
+	if (len >= 0) {
+		/* Trim from head */
+		m->m_data += len;
+		m->m_len -= len;
+	} else {
+		/* Trim from tail */
+		len = -len;
+		m->m_len -= len;
+	}
+}
+
+
+/*
+ * Copy len bytes from m, starting off bytes into n
+ */
+int
+m_copy(n, m, off, len)
+	struct mbuf *n, *m;
+	int off, len;
+{
+	if (len > M_FREEROOM(n))
+		return -1;
+
+	memcpy((n->m_data + n->m_len), (m->m_data + off), len);
+	n->m_len += len;
+	return 0;
+}
+
+
+/*
+ * Given a pointer into an mbuf, return the mbuf
+ * XXX This is a kludge, I should eliminate the need for it
+ * Fortunately, it's not used often
+ */
+struct mbuf *
+dtom(dat)
+	void *dat;
+{
+	struct mbuf *m;
+	
+	DEBUG_CALL("dtom");
+	DEBUG_ARG("dat = %lx", (long )dat);
+
+	/* bug corrected for M_EXT buffers */
+	for (m = m_usedlist.m_next; m != &m_usedlist; m = m->m_next) {
+	  if (m->m_flags & M_EXT) {
+	    if( (char *)dat>=m->m_ext && (char *)dat<(m->m_ext + m->m_size) )
+	      return m;
+	  } else {
+	    if( (char *)dat >= m->m_dat && (char *)dat<(m->m_dat + m->m_size) )
+	      return m;
+	  }
+	}
+	
+	DEBUG_ERROR((dfd, "dtom failed"));
+	
+	return (struct mbuf *)0;
+}
+