From 3ca52e72dbe435ba709f7e2b7436dd7fe630ab25 Mon Sep 17 00:00:00 2001
From: spz <spz@NetBSD.org>
Date: Sun, 12 Dec 2004 21:04:16 +0000
Subject: [PATCH] adds a description of m_apply closes PR kern/26059 has been
 looked at by Jason Thorpe and Christos Zoulas

---
 share/man/man9/mbuf.9 | 35 +++++++++++++++++++++++++++++++++--
 1 file changed, 33 insertions(+), 2 deletions(-)

diff --git a/share/man/man9/mbuf.9 b/share/man/man9/mbuf.9
index 106f57c53728..ecb88a6fd96c 100644
--- a/share/man/man9/mbuf.9
+++ b/share/man/man9/mbuf.9
@@ -1,4 +1,4 @@
-.\"	$NetBSD: mbuf.9,v 1.30 2004/09/06 16:25:29 wiz Exp $
+.\"	$NetBSD: mbuf.9,v 1.31 2004/12/12 21:04:16 spz Exp $
 .\"
 .\" Copyright (c) 1997 The NetBSD Foundation, Inc.
 .\" All rights reserved.
@@ -34,7 +34,7 @@
 .\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 .\" POSSIBILITY OF SUCH DAMAGE.
 .\"
-.Dd September 6, 2004
+.Dd December 12, 2004
 .Dt MBUF 9
 .Os
 .Sh NAME
@@ -56,6 +56,7 @@
 .Nm m_pullup ,
 .Nm m_split ,
 .Nm m_adj ,
+.Nm m_apply ,
 .Nm m_free ,
 .Nm m_freem ,
 .Nm mtod ,
@@ -112,6 +113,8 @@
 .Fn m_split "struct mbuf *m0" "int len0" "int wait"
 .Ft void
 .Fn m_adj "struct mbuf *mp" "int req_len"
+.Ft int
+.Fn m_apply "struct mbuf *m" "int off" "int len" "int *f(void *, caddr_t, unsigned int)" "void *arg"
 .Ft struct mbuf *
 .Fn m_free "struct mbuf *m"
 .Ft void
@@ -508,6 +511,34 @@ from the back (and if it is zero, the mbuf will stay bearded).
 This function does not move data in any way, but is used to manipulate the
 data area pointer and data length variable of the mbuf in a non-clobbering
 way.
+.It Fn m_apply "struct mbuf *m" "int off" "int len" "int (*f)(void *, caddr_t, unsigned int)" "void *arg"
+Apply function 
+.Fa f 
+to the data in an mbuf chain starting 
+.Fa off 
+bytes from the beginning, continuing for 
+.Fa len 
+bytes. Neither
+.Fa off 
+nor
+.Fa len 
+may be negative. 
+.Fa arg 
+will be supplied as first argument for
+.Fa f ,
+the second argument will be the pointer to the data buffer of a
+packet (starting after 
+.Fa off
+bytes in the stream), and the third argument is the amount 
+of data in bytes in this call. If
+.Fa f 
+returns something not equal to 
+.Dv zero 
+.Fn m_apply 
+will bail out, returning the return code of
+.Fa f .
+Upon successful completion it will return 
+.Dv zero .
 .It Fn m_free "struct mbuf *m"
 Frees mbuf
 .Fa m .