iPXE
iobpad.c
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1 /*
2  * Copyright (C) 2007 Michael Brown <mbrown@fensystems.co.uk>.
3  *
4  * This program is free software; you can redistribute it and/or
5  * modify it under the terms of the GNU General Public License as
6  * published by the Free Software Foundation; either version 2 of the
7  * License, or any later version.
8  *
9  * This program is distributed in the hope that it will be useful, but
10  * WITHOUT ANY WARRANTY; without even the implied warranty of
11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12  * General Public License for more details.
13  *
14  * You should have received a copy of the GNU General Public License
15  * along with this program; if not, write to the Free Software
16  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
17  * 02110-1301, USA.
18  *
19  * You can also choose to distribute this program under the terms of
20  * the Unmodified Binary Distribution Licence (as given in the file
21  * COPYING.UBDL), provided that you have satisfied its requirements.
22  */
23 
24 FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
25 
26 /**
27  * @file
28  *
29  * I/O buffer padding
30  *
31  */
32 
33 #include <string.h>
34 #include <ipxe/iobuf.h>
35 
36 /**
37  * Pad I/O buffer
38  *
39  * @v iobuf I/O buffer
40  * @v min_len Minimum length
41  *
42  * This function pads and aligns I/O buffers, for devices that
43  * aren't capable of padding in hardware, or that require specific
44  * alignment in TX buffers. The packet data will end up aligned to a
45  * multiple of @c IOB_ALIGN.
46  *
47  * @c min_len must not exceed @v IOB_ZLEN.
48  */
49 void iob_pad ( struct io_buffer *iobuf, size_t min_len ) {
50  void *data;
51  size_t len;
52  size_t headroom;
53  signed int pad_len;
54 
55  assert ( min_len <= IOB_ZLEN );
56 
57  /* Move packet data to start of I/O buffer. This will both
58  * align the data (since I/O buffers are aligned to
59  * IOB_ALIGN) and give us sufficient space for the
60  * zero-padding
61  */
62  data = iobuf->data;
63  len = iob_len ( iobuf );
64  headroom = iob_headroom ( iobuf );
65  iob_push ( iobuf, headroom );
66  memmove ( iobuf->data, data, len );
67  iob_unput ( iobuf, headroom );
68 
69  /* Pad to minimum packet length */
70  pad_len = ( min_len - iob_len ( iobuf ) );
71  if ( pad_len > 0 )
72  memset ( iob_put ( iobuf, pad_len ), 0, pad_len );
73 }
#define iob_put(iobuf, len)
Definition: iobuf.h:116
#define iob_push(iobuf, len)
Definition: iobuf.h:80
I/O buffers.
FILE_LICENCE(GPL2_OR_LATER_OR_UBDL)
assert((readw(&hdr->flags) &(GTF_reading|GTF_writing))==0)
static void size_t min_len
Definition: entropy.h:152
#define iob_unput(iobuf, len)
Definition: iobuf.h:131
static size_t iob_len(struct io_buffer *iobuf)
Calculate length of data in an I/O buffer.
Definition: iobuf.h:151
void * memmove(void *dest, const void *src, size_t len) __nonnull
static size_t iob_headroom(struct io_buffer *iobuf)
Calculate available space at start of an I/O buffer.
Definition: iobuf.h:161
uint32_t len
Length.
Definition: ena.h:14
#define IOB_ZLEN
Minimum I/O buffer length.
Definition: iobuf.h:23
void * data
Start of data.
Definition: iobuf.h:44
struct arbelprm_port_state_change_st data
Message.
Definition: arbel.h:12
String functions.
void iob_pad(struct io_buffer *iobuf, size_t min_len)
Pad I/O buffer.
Definition: iobpad.c:49
void * memset(void *dest, int character, size_t len) __nonnull
A persistent I/O buffer.
Definition: iobuf.h:32