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/****************************************************************************
* net/iob/iob_copyin.c
*
* Copyright (C) 2014 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* 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.
* 3. Neither the name NuttX nor the names of its contributors may be
* used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "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
* COPYRIGHT OWNER OR CONTRIBUTORS 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.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#if defined(CONFIG_DEBUG) && defined(CONFIG_IOB_DEBUG)
/* Force debug output (from this file only) */
# undef CONFIG_DEBUG_NET
# define CONFIG_DEBUG_NET 1
#endif
#include <stdint.h>
#include <string.h>
#include <errno.h>
#include <assert.h>
#include <debug.h>
#include <nuttx/net/iob.h>
#include "iob.h"
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
#ifndef MIN
# define MIN(a,b) ((a) < (b) ? (a) : (b))
#endif
/****************************************************************************
* Private Types
****************************************************************************/
/****************************************************************************
* Private Data
****************************************************************************/
/****************************************************************************
* Public Data
****************************************************************************/
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: iob_copyin
*
* Description:
* Copy data 'len' bytes from a user buffer into the I/O buffer chain,
* starting at 'offset', extending the chain as necessary.
*
****************************************************************************/
int iob_copyin(FAR struct iob_s *iob, FAR const uint8_t *src,
unsigned int len, unsigned int offset, bool throttled)
{
FAR struct iob_s *head = iob;
FAR struct iob_s *next;
FAR uint8_t *dest;
unsigned int ncopy;
unsigned int avail;
nllvdbg("iob=%p len=%u offset=%u\n", iob, len, offset);
DEBUGASSERT(iob && src);
/* The offset must applied to data that is already in the I/O buffer chain */
if (offset > iob->io_pktlen)
{
ndbg("ERROR: offset is past the end of data: %u > %u\n",
offset, iob->io_pktlen);
return -ESPIPE;
}
/* Skip to the I/O buffer containing the data offset */
while (offset > iob->io_len)
{
offset -= iob->io_len;
iob = iob->io_flink;
}
/* Then loop until all of the I/O data is copied from the user buffer */
while (len > 0)
{
next = iob->io_flink;
/* Get the destination I/O buffer address and the amount of data
* available from that address.
*/
dest = &iob->io_data[iob->io_offset + offset];
avail = iob->io_len - offset;
nllvdbg("iob=%p avail=%u len=%u next=%p\n", iob, avail, len, next);
/* Will the rest of the copy fit into this buffer, overwriting
* existing data.
*/
if (len > avail)
{
/* No.. Is this the last buffer in the chain? */
if (next)
{
/* No.. clip to size that will overwrite. We cannot
* extend the length of an I/O block in mid-chain.
*/
ncopy = avail;
}
else
{
unsigned int maxlen;
unsigned int newlen;
/* Yes.. We can extend this buffer to the up to the very end. */
maxlen = CONFIG_IOB_BUFSIZE - iob->io_offset;
/* This is the new buffer length that we need. Of course,
* clipped to the maximum possible size in this buffer.
*/
newlen = len + offset;
if (newlen > maxlen)
{
newlen = maxlen;
}
/* Set the new length and increment the packet length */
head->io_pktlen += (newlen - iob->io_len);
iob->io_len = newlen;
/* Set the new number of bytes to copy */
ncopy = newlen - offset;
}
}
else
{
/* Yes.. Copy all of the remaining bytes */
ncopy = len;
}
/* Copy from the user buffer to the I/O buffer. */
memcpy(dest, src, ncopy);
nllvdbg("iob=%p Copy %u bytes new len=%u\n",
iob, ncopy, iob->io_len);
/* Adjust the total length of the copy and the destination address in
* the user buffer.
*/
len -= ncopy;
src += ncopy;
/* Skip to the next I/O buffer in the chain. First, check if we
* are at the end of the buffer chain.
*/
if (len > 0 && !next)
{
/* Yes.. allocate a new buffer */
next = iob_alloc(throttled);
if (next == NULL)
{
ndbg("ERROR: Failed to allocate I/O buffer\n");
return -ENOMEM;
}
/* Add the new, empty I/O buffer to the end of the buffer chain. */
iob->io_flink = next;
nllvdbg("iob=%p added to the chain\n", iob);
}
iob = next;
offset = 0;
}
return 0;
}
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