223 lines
5.7 KiB
Groff
223 lines
5.7 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 20, 2001
|
|
.Dt MBCHAIN 9
|
|
.Os
|
|
.Sh NAME
|
|
.Nm mbchain ,
|
|
.Nm mb_init ,
|
|
.Nm mb_initm ,
|
|
.Nm mb_done ,
|
|
.Nm mb_detach ,
|
|
.Nm mb_fixhdr ,
|
|
.Nm mb_reserve ,
|
|
.Nm mb_put_uint8 ,
|
|
.Nm mb_put_uint16be ,
|
|
.Nm mb_put_uint16le ,
|
|
.Nm mb_put_uint32be ,
|
|
.Nm mb_put_uint32le ,
|
|
.Nm mb_put_int64be ,
|
|
.Nm mb_put_int64le ,
|
|
.Nm mb_put_mem ,
|
|
.Nm mb_put_mbuf ,
|
|
.Nm mb_put_uio
|
|
.Nd "set of functions to build an mbuf chain from 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 int
|
|
.Fn mb_init "struct mbchain *mbp"
|
|
.Ft void
|
|
.Fn mb_initm "struct mbchain *mbp" "struct mbuf *m"
|
|
.Ft void
|
|
.Fn mb_done "struct mbchain *mbp"
|
|
.Ft struct mbuf *
|
|
.Fn mb_detach "struct mbchain *mbp"
|
|
.Ft int
|
|
.Fn mb_fixhdr "struct mbchain *mbp"
|
|
.Ft caddr_t
|
|
.Fn mb_reserve "struct mbchain *mbp" "int size"
|
|
.Ft int
|
|
.Fn mb_put_uint8 "struct mbchain *mbp" "uint8_t x"
|
|
.Ft int
|
|
.Fn mb_put_uint16be "struct mbchain *mbp" "uint16_t x"
|
|
.Ft int
|
|
.Fn mb_put_uint16le "struct mbchain *mbp" "uint16_t x"
|
|
.Ft int
|
|
.Fn mb_put_uint32be "struct mbchain *mbp" "uint32_t x"
|
|
.Ft int
|
|
.Fn mb_put_uint32le "struct mbchain *mbp" "uint32_t x"
|
|
.Ft int
|
|
.Fn mb_put_int64be "struct mbchain *mbp" "int64_t x"
|
|
.Ft int
|
|
.Fn mb_put_int64le "struct mbchain *mbp" "int64_t x"
|
|
.Ft int
|
|
.Fn mb_put_mem "struct mbchain *mbp" "c_caddr_t source" "int size" "int type"
|
|
.Ft int
|
|
.Fn mb_put_mbuf "struct mbchain *mbp" "struct mbuf *m"
|
|
.Ft int
|
|
.Fn mb_put_uio "struct mbchain *mbp" "struct uio *uiop" "int size"
|
|
.Sh DESCRIPTION
|
|
These functions are used to compose mbuf chains from various data types.
|
|
The
|
|
.Vt mbchain
|
|
structure is used as a working context and should be initialized with a call
|
|
to either
|
|
.Fn mb_init
|
|
or
|
|
.Fn mb_initm .
|
|
It has the following fields:
|
|
.Bl -tag -width ".Va mb_count"
|
|
.It Va "mb_top"
|
|
.Pq Vt "struct mbuf *"
|
|
A pointer to the top of constructed mbuf chain.
|
|
.It Va mb_cur
|
|
.Pq Vt "struct mbuf *"
|
|
A pointer to the currently filled mbuf.
|
|
.It Va mb_mleft
|
|
.Pq Vt int
|
|
Number of bytes left in the current mbuf.
|
|
.It Va mb_count
|
|
.Pq Vt int
|
|
Total number of bytes placed in the mbuf chain.
|
|
.It Va mb_copy
|
|
.Pq Vt "mb_copy_t *"
|
|
User-defined function to perform a copy into mbuf;
|
|
useful if any unusual
|
|
data conversion is necessary.
|
|
.It Va mb_udata
|
|
.Pq Vt "void *"
|
|
User-supplied data which can be used in the
|
|
.Va mb_copy
|
|
function.
|
|
.El
|
|
.Pp
|
|
.Fn mb_done
|
|
function disposes an mbuf chain pointed to by
|
|
.Fa mbp->mb_top
|
|
field and sets
|
|
the field to
|
|
.Dv NULL .
|
|
.Pp
|
|
.Fn mb_detach
|
|
function returns the value of
|
|
.Fa mbp->mb_top
|
|
field and sets its value to
|
|
.Dv NULL .
|
|
.Pp
|
|
.Fn mb_fixhdr
|
|
recalculates the length of an mbuf chain and updates the
|
|
.Va m_pkthdr.len
|
|
field of the first mbuf in the chain.
|
|
It returns the calculated length.
|
|
.Pp
|
|
.Fn mb_reserve
|
|
ensures that the object of the length specified by the
|
|
.Fa size
|
|
argument will fit in the current mbuf (mbuf allocation is performed if
|
|
necessary), and advances all pointers as if the real data was placed.
|
|
Returned
|
|
value will point to the beginning of the reserved space.
|
|
Note that the size
|
|
of the object should not exceed
|
|
.Dv MLEN
|
|
bytes.
|
|
.Pp
|
|
All
|
|
.Fn mb_put_*
|
|
functions perform an actual copy of the data into mbuf chain.
|
|
Functions which have
|
|
.Cm le
|
|
or
|
|
.Cm be
|
|
suffixes will perform conversion to the little\- or big\-endian data formats.
|
|
.Pp
|
|
.Fn mb_put_mem
|
|
function copies
|
|
.Fa size
|
|
bytes of data specified by the
|
|
.Fa source
|
|
argument to 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
|
|
.Fn bcopy
|
|
function.
|
|
.It Dv MB_MUSER
|
|
Use
|
|
.Xr copyin 9
|
|
function.
|
|
.It Dv MB_MINLINE
|
|
Use an
|
|
.Dq inline
|
|
loop which does not call any function.
|
|
.It Dv MB_MZERO
|
|
Do not copy any data, but just fill the destination with zero bytes.
|
|
.It Dv MB_MCUSTOM
|
|
Call function specified by the
|
|
.Fa mbp->mb_copy
|
|
field.
|
|
.El
|
|
.Sh RETURN VALUES
|
|
All
|
|
.Ft int
|
|
functions except
|
|
.Fn mb_fixhdr
|
|
return zero if successful and an error code otherwise.
|
|
.Pp
|
|
.Em Note :
|
|
after failure of any function, an mbuf chain is left in the broken state,
|
|
and only
|
|
.Fn mb_done
|
|
function can safely be called to destroy it.
|
|
.Sh EXAMPLES
|
|
.Bd -literal
|
|
struct mbchain *mbp;
|
|
struct mbuf *m;
|
|
|
|
mb_init(mbp);
|
|
mb_put_uint8(mbp, 33);
|
|
mb_put_uint16le(mbp, length);
|
|
m = m_copym(mbp->mb_top, 0, M_COPYALL, M_WAIT);
|
|
send(m);
|
|
mb_done(mbp);
|
|
.Ed
|
|
.Sh SEE ALSO
|
|
.Xr mbuf 9 ,
|
|
.Xr mdchain 9
|
|
.Sh AUTHORS
|
|
This manual page was written by
|
|
.An Boris Popov Aq Mt bp@FreeBSD.org .
|