Add buf_seek() as buf_reserve() fails if a buf_add()/buf_reserve() is

called afterwards as it may realloc() the buffer and so the returned
pointer is bogus. Needed by the upcomming originate LSA code.
OK henning@

2 files changed, 13 insertions, 2 deletions

diff --git a/usr.sbin/ospfd/buffer.c b/usr.sbin/ospfd/buffer.c
index 42d160499ed..41693565a10 100644
--- a/usr.sbin/ospfd/buffer.c
+++ b/usr.sbin/ospfd/buffer.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: buffer.c,v 1.2 2005/02/01 21:25:18 claudio Exp $ */
+/*	$OpenBSD: buffer.c,v 1.3 2005/02/09 14:39:56 claudio Exp $ */
 
 /*
  * Copyright (c) 2003, 2004 Henning Brauer <henning@openbsd.org>
@@ -111,6 +111,16 @@ buf_reserve(struct buf *buf, size_t len)
 	return (b);
 }
 
+void *
+buf_seek(struct buf *buf, size_t pos, size_t len)
+{
+	/* only allowed to seek in already written parts */
+	if (pos + len > buf->wpos)
+		return (NULL);
+
+	return (buf->buf + pos);
+}
+
 int
 buf_close(struct msgbuf *msgbuf, struct buf *buf)
 {
diff --git a/usr.sbin/ospfd/ospfd.h b/usr.sbin/ospfd/ospfd.h
index 6d954ad2442..78e114c50ab 100644
--- a/usr.sbin/ospfd/ospfd.h
+++ b/usr.sbin/ospfd/ospfd.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: ospfd.h,v 1.5 2005/02/07 05:51:00 david Exp $ */
+/*	$OpenBSD: ospfd.h,v 1.6 2005/02/09 14:39:56 claudio Exp $ */
 
 /*
  * Copyright (c) 2004 Esben Norby <norby@openbsd.org>
@@ -367,6 +367,7 @@ struct buf	*buf_open(size_t);
 struct buf	*buf_dynamic(size_t, size_t);
 int		 buf_add(struct buf *, void *, size_t);
 void		*buf_reserve(struct buf *, size_t);
+void		*buf_seek(struct buf *, size_t, size_t);
 int		 buf_close(struct msgbuf *, struct buf *);
 int		 buf_write(int, struct buf *);
 void		 buf_free(struct buf *);