2 This file is part of GNUnet.
3 (C) 2010 Christian Grothoff (and other contributing authors)
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6 it under the terms of the GNU General Public License as published
7 by the Free Software Foundation; either version 2, or (at your
8 option) any later version.
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11 WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 General Public License for more details.
15 You should have received a copy of the GNU General Public License
16 along with GNUnet; see the file COPYING. If not, write to the
17 Free Software Foundation, Inc., 59 Temple Place - Suite 330,
18 Boston, MA 02111-1307, USA.
22 * @file util/server_mst.c
23 * @brief convenience functions for handling inbound message buffers
24 * @author Christian Grothoff
28 #include "gnunet_common.h"
29 #include "gnunet_connection_lib.h"
30 #include "gnunet_scheduler_lib.h"
31 #include "gnunet_server_lib.h"
32 #include "gnunet_time_lib.h"
34 #define DEBUG_SERVER_MST GNUNET_NO
36 #if HAVE_UNALIGNED_64_ACCESS
37 #define ALIGN_FACTOR 4
39 #define ALIGN_FACTOR 8
44 * Handle to a message stream tokenizer.
46 struct GNUNET_SERVER_MessageStreamTokenizer
50 * Function to call on completed messages.
52 GNUNET_SERVER_MessageTokenizerCallback cb;
60 * Size of the buffer (starting at 'hdr').
65 * How many bytes in buffer have we already processed?
70 * How many bytes in buffer are valid right now?
75 * Beginning of the buffer. Typed like this to force alignment.
77 struct GNUNET_MessageHeader hdr;
84 * Create a message stream tokenizer.
86 * @param maxbuf maximum message size to support (typically
87 * GNUNET_SERVER_MAX_MESSAGE_SIZE)
88 * @param cb function to call on completed messages
89 * @param cb_cls closure for cb
90 * @return handle to tokenizer
92 struct GNUNET_SERVER_MessageStreamTokenizer *
93 GNUNET_SERVER_mst_create (size_t maxbuf,
94 GNUNET_SERVER_MessageTokenizerCallback cb,
97 struct GNUNET_SERVER_MessageStreamTokenizer *ret;
99 ret = GNUNET_malloc (maxbuf + sizeof (struct GNUNET_SERVER_MessageStreamTokenizer));
100 ret->maxbuf = maxbuf;
102 ret->cb_cls = cb_cls;
108 * Add incoming data to the receive buffer and call the
109 * callback for all complete messages.
111 * @param mst tokenizer to use
112 * @param client_identity ID of client for which this is a buffer
113 * @param buf input data to add
114 * @param size number of bytes in buf
115 * @param purge should any excess bytes in the buffer be discarded
116 * (i.e. for packet-based services like UDP)
117 * @param one_shot only call callback once, keep rest of message in buffer
118 * @return GNUNET_OK if we are done processing (need more data)
119 * GNUNET_NO if one_shot was set and we have another message ready
120 * GNUNET_SYSERR if the data stream is corrupt
123 GNUNET_SERVER_mst_receive (struct GNUNET_SERVER_MessageStreamTokenizer *mst,
130 const struct GNUNET_MessageHeader *hdr;
135 unsigned long offset;
139 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
140 "Server-mst receives %u bytes with %u bytes already in private buffer\n",
142 (unsigned int) (mst->pos - mst->off));
145 ibuf = (char*) &mst->hdr;
149 if ( (mst->maxbuf - mst->off < sizeof (struct GNUNET_MessageHeader)) ||
150 (0 != (mst->off % ALIGN_FACTOR)) )
152 /* need to align or need more space */
153 mst->pos -= mst->off;
159 if (mst->pos - mst->off < sizeof (struct GNUNET_MessageHeader))
161 delta = GNUNET_MIN (sizeof (struct GNUNET_MessageHeader) - (mst->pos - mst->off),
163 memcpy (&ibuf[mst->pos],
170 if (mst->pos - mst->off < sizeof (struct GNUNET_MessageHeader))
179 hdr = (const struct GNUNET_MessageHeader*) &ibuf[mst->off];
180 want = ntohs (hdr->size);
181 if (want < sizeof (struct GNUNET_MessageHeader))
184 return GNUNET_SYSERR;
186 if (mst->maxbuf - mst->off < want)
188 /* need more space */
189 mst->pos -= mst->off;
195 if (mst->pos - mst->off < want)
197 delta = GNUNET_MIN (want - (mst->pos - mst->off),
199 memcpy (&ibuf[mst->pos],
206 if (mst->pos - mst->off < want)
215 if (one_shot == GNUNET_SYSERR)
217 /* cannot call callback again, but return value saying that
218 we have another full message in the buffer */
222 if (one_shot == GNUNET_YES)
223 one_shot = GNUNET_SYSERR;
224 mst->cb (mst->cb_cls, client, hdr);
226 if (mst->off == mst->pos)
228 /* reset to beginning of buffer, it's free right now! */
236 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
237 "Server-mst has %u bytes left in inbound buffer\n",
238 (unsigned int) size);
240 if (size < sizeof (struct GNUNET_MessageHeader))
242 offset = (unsigned long) buf;
243 need_align = (0 != offset % ALIGN_FACTOR) ? GNUNET_YES : GNUNET_NO;
244 if (GNUNET_NO == need_align)
246 /* can try to do zero-copy and process directly from original buffer */
247 hdr = (const struct GNUNET_MessageHeader *) buf;
248 want = ntohs (hdr->size);
250 break; /* or not, buffer incomplete, so copy to private buffer... */
251 if (one_shot == GNUNET_SYSERR)
253 /* cannot call callback again, but return value saying that
254 we have another full message in the buffer */
258 if (one_shot == GNUNET_YES)
259 one_shot = GNUNET_SYSERR;
260 mst->cb (mst->cb_cls, client, hdr);
266 /* need to copy to private buffer to align;
267 yes, we go a bit more spagetti than usual here */
272 if ( (size > 0) && (! purge) )
274 GNUNET_assert (mst->pos + size <= mst->maxbuf);
275 memcpy (&ibuf[mst->pos], buf, size);
281 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
282 "Server-mst leaves %u bytes in private buffer\n",
283 (unsigned int) (mst->pos - mst->off));
290 * Destroys a tokenizer.
292 * @param mst tokenizer to destroy
295 GNUNET_SERVER_mst_destroy (struct GNUNET_SERVER_MessageStreamTokenizer *mst)
302 /* end of server_mst.c */