212 lines
5.3 KiB
Groff
212 lines
5.3 KiB
Groff
.\" -*- nroff -*-
|
|
.\"
|
|
.\" Copyright (c) 2001 Boris Popov
|
|
.\"
|
|
.\" Redistribution and use in source and binary forms, with or without
|
|
.\" modification, are permitted provided that the following conditions
|
|
.\" are met:
|
|
.\" 1. Redistributions of source code must retain the above copyright
|
|
.\" notice, this list of conditions and the following disclaimer.
|
|
.\" 2. Redistributions in binary form must reproduce the above copyright
|
|
.\" notice, this list of conditions and the following disclaimer in the
|
|
.\" documentation and/or other materials provided with the distribution.
|
|
.\"
|
|
.\" THIS SOFTWARE IS PROVIDED BY THE DEVELOPERS ``AS IS'' AND ANY EXPRESS OR
|
|
.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
|
|
.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
|
|
.\" IN NO EVENT SHALL THE DEVELOPERS BE LIABLE FOR ANY DIRECT, INDIRECT,
|
|
.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
|
|
.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
|
|
.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
|
|
.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
|
|
.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
|
|
.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
|
|
.\"
|
|
.\" $FreeBSD$
|
|
.\"
|
|
.Dd February 28, 2001
|
|
.Dt MDCHAIN 9
|
|
.Os
|
|
.Sh NAME
|
|
.Nm mdchain ,
|
|
.Nm md_initm ,
|
|
.Nm md_done ,
|
|
.Nm md_append_record ,
|
|
.Nm md_next_record ,
|
|
.Nm md_get_uint8 ,
|
|
.Nm md_get_uint16 ,
|
|
.Nm md_get_uint16be ,
|
|
.Nm md_get_uint16le ,
|
|
.Nm md_get_uint32 ,
|
|
.Nm md_get_uint32be ,
|
|
.Nm md_get_uint32le ,
|
|
.Nm md_get_int64 ,
|
|
.Nm md_get_int64be ,
|
|
.Nm md_get_int64le ,
|
|
.Nm md_get_mem ,
|
|
.Nm md_get_mbuf ,
|
|
.Nm md_get_uio
|
|
.Nd "set of functions to dissect an mbuf chain to various data types"
|
|
.Sh SYNOPSIS
|
|
.Cd options LIBMCHAIN
|
|
.Li kldload libmchain
|
|
.Pp
|
|
.In sys/param.h
|
|
.In sys/uio.h
|
|
.In sys/mchain.h
|
|
.Ft void
|
|
.Fn md_initm "struct mdchain *mdp" "struct mbuf *m"
|
|
.Ft void
|
|
.Fn md_done "struct mdchain *mdp"
|
|
.Ft void
|
|
.Fn md_append_record "struct mdchain *mdp" "struct mbuf *top"
|
|
.Ft int
|
|
.Fn md_next_record "struct mdchain *mdp"
|
|
.Ft int
|
|
.Fn md_get_uint8 "struct mdchain *mdp" "u_int8_t *x"
|
|
.Ft int
|
|
.Fn md_get_uint16 "struct mdchain *mdp" "u_int16_t *x"
|
|
.Ft int
|
|
.Fn md_get_uint16be "struct mdchain *mdp" "u_int16_t *x"
|
|
.Ft int
|
|
.Fn md_get_uint16le "struct mdchain *mdp" "u_int16_t *x"
|
|
.Ft int
|
|
.Fn md_get_uint32 "struct mdchain *mdp" "u_int32_t *x"
|
|
.Ft int
|
|
.Fn md_get_uint32be "struct mdchain *mdp" "u_int32_t *x"
|
|
.Ft int
|
|
.Fn md_get_uint32le "struct mdchain *mdp" "u_int32_t *x"
|
|
.Ft int
|
|
.Fn md_get_int64 "struct mdchain *mdp" "int64_t *x"
|
|
.Ft int
|
|
.Fn md_get_int64be "struct mdchain *mdp" "int64_t *x"
|
|
.Ft int
|
|
.Fn md_get_int64le "struct mdchain *mdp" "int64_t *x"
|
|
.Ft int
|
|
.Fn md_get_mem "struct mdchain *mdp" "caddr_t target" "int size" "int type"
|
|
.Ft int
|
|
.Fn md_get_mbuf "struct mdchain *mdp" "int size" "struct mbuf **m"
|
|
.Ft int
|
|
.Fn md_get_uio "struct mdchain *mdp" "struct uio *uiop" "int size"
|
|
.Sh DESCRIPTION
|
|
These functions are used to decompose mbuf chains to various data types.
|
|
The
|
|
.Vt mdchain
|
|
structure is used as a working context
|
|
and should be initialized through a call of the
|
|
.Fn mb_initm
|
|
function.
|
|
It has the following fields:
|
|
.Bl -tag -width "md_top"
|
|
.It Va "md_top"
|
|
.Pq Vt "struct mbuf *"
|
|
A pointer to the top of the parsed mbuf chain.
|
|
.It Va md_cur
|
|
.Pq Vt "struct mbuf *"
|
|
A pointer to the currently parsed mbuf.
|
|
.It Va md_pas
|
|
.Pq Vt int
|
|
Offset in the current mbuf.
|
|
.El
|
|
.Pp
|
|
The
|
|
.Fn md_done
|
|
function disposes of an mbuf chain pointed to by the
|
|
.Fa mdp->md_top
|
|
field and sets the field to
|
|
.Dv NULL .
|
|
.Pp
|
|
The
|
|
.Fn md_append_record
|
|
appends a new mbuf chain using
|
|
.Va m_nextpkt
|
|
field to form a single linked list of mbuf chains.
|
|
If the
|
|
.Fa mdp->md_top
|
|
field is
|
|
.Dv NULL ,
|
|
then this function behaves exactly as the
|
|
.Fn md_initm
|
|
function.
|
|
.Pp
|
|
The
|
|
.Fn md_next_record
|
|
function extracts the next mbuf chain and disposes the current one, if any.
|
|
For a new mbuf chain it calls the
|
|
.Fn md_initm
|
|
function.
|
|
If there is no data left the function returns
|
|
.Er ENOENT .
|
|
.Pp
|
|
All
|
|
.Fn md_get_*
|
|
functions perform an actual copy of the data from an mbuf chain.
|
|
Functions which have
|
|
.Cm le
|
|
or
|
|
.Cm be
|
|
suffixes will perform conversion to the little\- or big\-endian data formats.
|
|
.Pp
|
|
.Fn md_get_mem
|
|
function copies
|
|
.Fa size
|
|
bytes of data specified by the
|
|
.Fa source
|
|
argument from an mbuf chain.
|
|
The
|
|
.Fa type
|
|
argument specifies the method used to perform a copy,
|
|
and can be one of the following:
|
|
.Bl -tag -width ".Dv MB_MINLINE"
|
|
.It Dv MB_MSYSTEM
|
|
Use the
|
|
.Fn bcopy
|
|
function.
|
|
.It Dv MB_MUSER
|
|
Use the
|
|
.Xr copyin 9
|
|
function.
|
|
.It Dv MB_MINLINE
|
|
Use an
|
|
.Dq inline
|
|
loop which does not call any function.
|
|
.El
|
|
.Pp
|
|
If
|
|
.Fa target
|
|
is
|
|
.Dv NULL ,
|
|
an actual copy is not performed
|
|
and the function just skips the given number of bytes.
|
|
.Sh RETURN VALUES
|
|
All
|
|
.Ft int
|
|
functions return zero if successful,
|
|
otherwise an error code is returned.
|
|
.Pp
|
|
.Em Note :
|
|
after failure of any function,
|
|
an mbuf chain is left in the broken state and only the
|
|
.Fn md_done
|
|
function can safely be called to destroy it.
|
|
.Sh EXAMPLES
|
|
.Bd -literal
|
|
struct mdchain *mdp;
|
|
struct mbuf *m;
|
|
u_int16_t length;
|
|
u_int8_t byte;
|
|
|
|
receive(so, &m);
|
|
md_initm(mdp, m);
|
|
if (md_get_uint8(mdp, &byte) != 0 ||
|
|
md_get_uint16le(mdp, &length) != 0)
|
|
error = EBADRPC;
|
|
mb_done(mdp);
|
|
.Ed
|
|
.Sh SEE ALSO
|
|
.Xr mbchain 9 ,
|
|
.Xr mbuf 9
|
|
.Sh AUTHORS
|
|
This manual page was written by
|
|
.An Boris Popov Aq bp@FreeBSD.org .
|