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/*
This file is part of GNUnet.
(C) 2009 Christian Grothoff (and other contributing authors)
GNUnet is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published
by the Free Software Foundation; either version 2, or (at your
option) any later version.
GNUnet is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
General Public License for more details.
You should have received a copy of the GNU General Public License
along with GNUnet; see the file COPYING. If not, write to the
Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA.
*/
/**
* @file util/server_mst.c
* @brief convenience functions for handling inbound message buffers
* @author Christian Grothoff
*/
#include "platform.h"
#include "gnunet_common.h"
#include "gnunet_connection_lib.h"
#include "gnunet_scheduler_lib.h"
#include "gnunet_server_lib.h"
#include "gnunet_time_lib.h"
/**
* Handle to a message stream tokenizer.
*/
struct GNUNET_SERVER_MessageStreamTokenizer
{
size_t maxbuf;
size_t off;
void *client_identity;
GNUNET_SERVER_MessageTokenizerCallback cb;
void *cb_cls;
/**
* Beginning of the buffer.
*/
struct GNUNET_MessageHeader hdr;
};
/**
* Create a message stream tokenizer.
*
* @param maxbuf maximum message size to support (typically
* GNUNET_SERVER_MAX_MESSAGE_SIZE)
* @param client_identity ID of client for which this is a buffer,
* can be NULL (will be passed back to 'cb')
* @return handle to tokenizer
*/
struct GNUNET_SERVER_MessageStreamTokenizer *
GNUNET_SERVER_mst_create (size_t maxbuf,
void *client_identity,
GNUNET_SERVER_MessageTokenizerCallback cb,
void *cb_cls)
{
struct GNUNET_SERVER_MessageStreamTokenizer *ret;
ret = GNUNET_malloc (maxbuf + sizeof (struct GNUNET_SERVER_MessageStreamTokenizer));
ret->maxbuf = maxbuf;
ret->client_identity = client_identity;
ret->cb = cb;
ret->cb_cls = cb_cls;
return ret;
}
/**
* Add incoming data to the receive buffer and call the
* callback for all complete messages.
*
* @param mst tokenizer to use
* @param buf input data to add
* @param size number of bytes in buf
* @param purge should any excess bytes in the buffer be discarded
* (i.e. for packet-based services like UDP)
* @param one_shot only call callback once, keep rest of message in buffer
* @return GNUNET_OK if we are done processing (need more data)
* GNUNET_NO if one_shot was set and we have another message ready
* GNUNET_SYSERR if the data stream is corrupt
*/
int
GNUNET_SERVER_mst_receive (struct GNUNET_SERVER_MessageStreamTokenizer *mst,
const char *buf,
size_t size,
int purge,
int one_shot)
{
const struct GNUNET_MessageHeader *hdr;
size_t delta;
size_t want;
char *ibuf;
int need_align;
unsigned long offset;
int ret;
ret = GNUNET_OK;
ibuf = (char*) &mst->hdr;
if (mst->off > 0)
{
do_align:
if (mst->off < sizeof (struct GNUNET_MessageHeader))
{
delta = GNUNET_MIN (sizeof (struct GNUNET_MessageHeader) - mst->off,
size);
memcpy (&ibuf[mst->off],
buf,
delta);
mst->off += delta;
buf += delta;
size -= delta;
}
if (mst->off < sizeof (struct GNUNET_MessageHeader))
{
if (purge)
mst->off = 0;
return GNUNET_OK;
}
want = ntohs (mst->hdr.size);
if (want < sizeof (struct GNUNET_MessageHeader))
{
GNUNET_break_op (0);
return GNUNET_SYSERR;
}
if (want < mst->off)
{
delta = GNUNET_MIN (want - mst->off,
size);
memcpy (&ibuf[mst->off],
buf,
delta);
mst->off += delta;
buf += delta;
size -= delta;
}
if (want < mst->off)
{
if (purge)
mst->off = 0;
return GNUNET_OK;
}
if (one_shot == GNUNET_SYSERR)
{
ret = GNUNET_NO;
goto copy;
}
if (one_shot == GNUNET_YES)
one_shot = GNUNET_SYSERR;
mst->cb (mst->cb_cls, mst->client_identity, &mst->hdr);
mst->off = 0;
}
while (size > 0)
{
if (size < sizeof (struct GNUNET_MessageHeader))
break;
offset = (unsigned long) buf;
#if HAVE_UNALIGNED_64_ACCESS
need_align = (0 != offset % 4) ? GNUNET_YES : GNUNET_NO;
#else
need_align = (0 != offset % 8) ? GNUNET_YES : GNUNET_NO;
#endif
if (GNUNET_NO == need_align)
{
/* can try to do zero-copy */
hdr = (const struct GNUNET_MessageHeader *) buf;
want = ntohs (hdr->size);
if (size < want)
break; /* or not, buffer incomplete... */
if (one_shot == GNUNET_SYSERR)
{
ret = GNUNET_NO;
goto copy;
}
if (one_shot == GNUNET_YES)
one_shot = GNUNET_SYSERR;
mst->cb (mst->cb_cls, mst->client_identity, hdr);
buf += want;
size -= want;
}
else
{
/* yes, we go a bit more spagetti than usual here */
goto do_align;
}
}
copy:
if ( (size > 0) && (! purge) )
{
memcpy (&ibuf[mst->off], buf, size);
mst->off += size;
size = 0;
}
if (purge)
mst->off = 0;
return ret;
}
/**
* Destroys a tokenizer.
*
* @param mst tokenizer to destroy
*/
void
GNUNET_SERVER_mst_destroy (struct GNUNET_SERVER_MessageStreamTokenizer *mst)
{
GNUNET_free (mst);
}
/* end of server_mst.c */
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