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 #if HAVE_UNALIGNED_64_ACCESS
35 #define ALIGN_FACTOR 4
37 #define ALIGN_FACTOR 8
42 * Handle to a message stream tokenizer.
44 struct GNUNET_SERVER_MessageStreamTokenizer
48 * Function to call on completed messages.
50 GNUNET_SERVER_MessageTokenizerCallback cb;
58 * Client to pass to cb.
60 void *client_identity;
63 * Size of the buffer (starting at 'hdr').
68 * How many bytes in buffer have we already processed?
73 * How many bytes in buffer are valid right now?
78 * Beginning of the buffer. Typed like this to force alignment.
80 struct GNUNET_MessageHeader hdr;
87 * Create a message stream tokenizer.
89 * @param maxbuf maximum message size to support (typically
90 * GNUNET_SERVER_MAX_MESSAGE_SIZE)
91 * @param client_identity ID of client for which this is a buffer,
92 * can be NULL (will be passed back to 'cb')
93 * @param cb function to call on completed messages
94 * @param cb_cls closure for cb
95 * @return handle to tokenizer
97 struct GNUNET_SERVER_MessageStreamTokenizer *
98 GNUNET_SERVER_mst_create (size_t maxbuf,
99 void *client_identity,
100 GNUNET_SERVER_MessageTokenizerCallback cb,
103 struct GNUNET_SERVER_MessageStreamTokenizer *ret;
105 ret = GNUNET_malloc (maxbuf + sizeof (struct GNUNET_SERVER_MessageStreamTokenizer));
106 ret->maxbuf = maxbuf;
107 ret->client_identity = client_identity;
109 ret->cb_cls = cb_cls;
115 * Add incoming data to the receive buffer and call the
116 * callback for all complete messages.
118 * @param mst tokenizer to use
119 * @param buf input data to add
120 * @param size number of bytes in buf
121 * @param purge should any excess bytes in the buffer be discarded
122 * (i.e. for packet-based services like UDP)
123 * @param one_shot only call callback once, keep rest of message in buffer
124 * @return GNUNET_OK if we are done processing (need more data)
125 * GNUNET_NO if one_shot was set and we have another message ready
126 * GNUNET_SYSERR if the data stream is corrupt
129 GNUNET_SERVER_mst_receive (struct GNUNET_SERVER_MessageStreamTokenizer *mst,
135 const struct GNUNET_MessageHeader *hdr;
140 unsigned long offset;
144 ibuf = (char*) &mst->hdr;
148 if ( (mst->maxbuf - mst->off < sizeof (struct GNUNET_MessageHeader)) ||
149 (0 != (mst->off % ALIGN_FACTOR)) )
151 /* need to align or need more space */
152 mst->pos -= mst->off;
158 if (mst->pos - mst->off < sizeof (struct GNUNET_MessageHeader))
160 delta = GNUNET_MIN (sizeof (struct GNUNET_MessageHeader) - (mst->pos - mst->off),
162 memcpy (&ibuf[mst->pos],
169 if (mst->pos - mst->off < sizeof (struct GNUNET_MessageHeader))
178 hdr = (const struct GNUNET_MessageHeader*) &ibuf[mst->off];
179 want = ntohs (hdr->size);
180 if (want < sizeof (struct GNUNET_MessageHeader))
183 return GNUNET_SYSERR;
185 if (mst->maxbuf - mst->off < want)
187 /* need more space */
188 mst->pos -= mst->off;
194 if (mst->pos - mst->off < want)
196 delta = GNUNET_MIN (want - (mst->pos - mst->off),
198 memcpy (&ibuf[mst->pos],
205 if (mst->pos - mst->off < want)
214 if (one_shot == GNUNET_SYSERR)
216 /* cannot call callback again, but return value saying that
217 we have another full message in the buffer */
221 if (one_shot == GNUNET_YES)
222 one_shot = GNUNET_SYSERR;
223 mst->cb (mst->cb_cls, mst->client_identity, hdr);
225 if (mst->off == mst->pos)
227 /* reset to beginning of buffer, it's free right now! */
234 if (size < sizeof (struct GNUNET_MessageHeader))
236 offset = (unsigned long) buf;
237 need_align = (0 != offset % ALIGN_FACTOR) ? GNUNET_YES : GNUNET_NO;
238 if (GNUNET_NO == need_align)
240 /* can try to do zero-copy and process directly from original buffer */
241 hdr = (const struct GNUNET_MessageHeader *) buf;
242 want = ntohs (hdr->size);
244 break; /* or not, buffer incomplete, so copy to private buffer... */
245 if (one_shot == GNUNET_SYSERR)
247 /* cannot call callback again, but return value saying that
248 we have another full message in the buffer */
252 if (one_shot == GNUNET_YES)
253 one_shot = GNUNET_SYSERR;
254 mst->cb (mst->cb_cls, mst->client_identity, hdr);
260 /* need to copy to private buffer to align;
261 yes, we go a bit more spagetti than usual here */
266 if ( (size > 0) && (! purge) )
268 GNUNET_assert (mst->pos + size <= mst->maxbuf);
269 memcpy (&ibuf[mst->pos], buf, size);
279 * Destroys a tokenizer.
281 * @param mst tokenizer to destroy
284 GNUNET_SERVER_mst_destroy (struct GNUNET_SERVER_MessageStreamTokenizer *mst)
291 /* end of server_mst.c */