2 This file is part of GNUnet.
3 (C) 2010 Christian Grothoff (and other contributing authors)
5 GNUnet is free software; you can redistribute it and/or modify
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 * Client to pass to cb.
62 void *client_identity;
65 * Size of the buffer (starting at 'hdr').
70 * How many bytes in buffer have we already processed?
75 * How many bytes in buffer are valid right now?
80 * Beginning of the buffer. Typed like this to force alignment.
82 struct GNUNET_MessageHeader hdr;
89 * Create a message stream tokenizer.
91 * @param maxbuf maximum message size to support (typically
92 * GNUNET_SERVER_MAX_MESSAGE_SIZE)
93 * @param client_identity ID of client for which this is a buffer,
94 * can be NULL (will be passed back to 'cb')
95 * @param cb function to call on completed messages
96 * @param cb_cls closure for cb
97 * @return handle to tokenizer
99 struct GNUNET_SERVER_MessageStreamTokenizer *
100 GNUNET_SERVER_mst_create (size_t maxbuf,
101 void *client_identity,
102 GNUNET_SERVER_MessageTokenizerCallback cb,
105 struct GNUNET_SERVER_MessageStreamTokenizer *ret;
107 ret = GNUNET_malloc (maxbuf + sizeof (struct GNUNET_SERVER_MessageStreamTokenizer));
108 ret->maxbuf = maxbuf;
109 ret->client_identity = client_identity;
111 ret->cb_cls = cb_cls;
117 * Add incoming data to the receive buffer and call the
118 * callback for all complete messages.
120 * @param mst tokenizer to use
121 * @param buf input data to add
122 * @param size number of bytes in buf
123 * @param purge should any excess bytes in the buffer be discarded
124 * (i.e. for packet-based services like UDP)
125 * @param one_shot only call callback once, keep rest of message in buffer
126 * @return GNUNET_OK if we are done processing (need more data)
127 * GNUNET_NO if one_shot was set and we have another message ready
128 * GNUNET_SYSERR if the data stream is corrupt
131 GNUNET_SERVER_mst_receive (struct GNUNET_SERVER_MessageStreamTokenizer *mst,
137 const struct GNUNET_MessageHeader *hdr;
142 unsigned long offset;
146 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
147 "Server-mst receives %u bytes with %u bytes already in private buffer\n",
149 (unsigned int) (mst->pos - mst->off));
152 ibuf = (char*) &mst->hdr;
156 if ( (mst->maxbuf - mst->off < sizeof (struct GNUNET_MessageHeader)) ||
157 (0 != (mst->off % ALIGN_FACTOR)) )
159 /* need to align or need more space */
160 mst->pos -= mst->off;
166 if (mst->pos - mst->off < sizeof (struct GNUNET_MessageHeader))
168 delta = GNUNET_MIN (sizeof (struct GNUNET_MessageHeader) - (mst->pos - mst->off),
170 memcpy (&ibuf[mst->pos],
177 if (mst->pos - mst->off < sizeof (struct GNUNET_MessageHeader))
186 hdr = (const struct GNUNET_MessageHeader*) &ibuf[mst->off];
187 want = ntohs (hdr->size);
188 if (want < sizeof (struct GNUNET_MessageHeader))
191 return GNUNET_SYSERR;
193 if (mst->maxbuf - mst->off < want)
195 /* need more space */
196 mst->pos -= mst->off;
202 if (mst->pos - mst->off < want)
204 delta = GNUNET_MIN (want - (mst->pos - mst->off),
206 memcpy (&ibuf[mst->pos],
213 if (mst->pos - mst->off < want)
222 if (one_shot == GNUNET_SYSERR)
224 /* cannot call callback again, but return value saying that
225 we have another full message in the buffer */
229 if (one_shot == GNUNET_YES)
230 one_shot = GNUNET_SYSERR;
231 mst->cb (mst->cb_cls, mst->client_identity, hdr);
233 if (mst->off == mst->pos)
235 /* reset to beginning of buffer, it's free right now! */
243 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
244 "Server-mst has %u bytes left in inbound buffer\n",
245 (unsigned int) size);
247 if (size < sizeof (struct GNUNET_MessageHeader))
249 offset = (unsigned long) buf;
250 need_align = (0 != offset % ALIGN_FACTOR) ? GNUNET_YES : GNUNET_NO;
251 if (GNUNET_NO == need_align)
253 /* can try to do zero-copy and process directly from original buffer */
254 hdr = (const struct GNUNET_MessageHeader *) buf;
255 want = ntohs (hdr->size);
257 break; /* or not, buffer incomplete, so copy to private buffer... */
258 if (one_shot == GNUNET_SYSERR)
260 /* cannot call callback again, but return value saying that
261 we have another full message in the buffer */
265 if (one_shot == GNUNET_YES)
266 one_shot = GNUNET_SYSERR;
267 mst->cb (mst->cb_cls, mst->client_identity, hdr);
273 /* need to copy to private buffer to align;
274 yes, we go a bit more spagetti than usual here */
279 if ( (size > 0) && (! purge) )
281 GNUNET_assert (mst->pos + size <= mst->maxbuf);
282 memcpy (&ibuf[mst->pos], buf, size);
288 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
289 "Server-mst leaves %u bytes in private buffer\n",
290 (unsigned int) (mst->pos - mst->off));
297 * Destroys a tokenizer.
299 * @param mst tokenizer to destroy
302 GNUNET_SERVER_mst_destroy (struct GNUNET_SERVER_MessageStreamTokenizer *mst)
309 /* end of server_mst.c */