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 3, 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.
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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_util_lib.h"
31 #if HAVE_UNALIGNED_64_ACCESS
32 #define ALIGN_FACTOR 4
34 #define ALIGN_FACTOR 8
37 #define LOG(kind,...) GNUNET_log_from (kind, "util", __VA_ARGS__)
41 * Handle to a message stream tokenizer.
43 struct GNUNET_SERVER_MessageStreamTokenizer
47 * Function to call on completed messages.
49 GNUNET_SERVER_MessageTokenizerCallback cb;
57 * Size of the buffer (starting at 'hdr').
62 * How many bytes in buffer have we already processed?
67 * How many bytes in buffer are valid right now?
72 * Beginning of the buffer. Typed like this to force alignment.
74 struct GNUNET_MessageHeader *hdr;
81 * Create a message stream tokenizer.
83 * @param cb function to call on completed messages
84 * @param cb_cls closure for cb
85 * @return handle to tokenizer
87 struct GNUNET_SERVER_MessageStreamTokenizer *
88 GNUNET_SERVER_mst_create (GNUNET_SERVER_MessageTokenizerCallback cb,
91 struct GNUNET_SERVER_MessageStreamTokenizer *ret;
93 ret = GNUNET_new (struct GNUNET_SERVER_MessageStreamTokenizer);
94 ret->hdr = GNUNET_malloc (GNUNET_SERVER_MIN_BUFFER_SIZE);
95 ret->curr_buf = GNUNET_SERVER_MIN_BUFFER_SIZE;
103 * Add incoming data to the receive buffer and call the
104 * callback for all complete messages.
106 * @param mst tokenizer to use
107 * @param client_identity ID of client for which this is a buffer
108 * @param buf input data to add
109 * @param size number of bytes in buf
110 * @param purge should any excess bytes in the buffer be discarded
111 * (i.e. for packet-based services like UDP)
112 * @param one_shot only call callback once, keep rest of message in buffer
113 * @return GNUNET_OK if we are done processing (need more data)
114 * GNUNET_NO if one_shot was set and we have another message ready
115 * GNUNET_SYSERR if the data stream is corrupt
118 GNUNET_SERVER_mst_receive (struct GNUNET_SERVER_MessageStreamTokenizer *mst,
119 void *client_identity, const char *buf, size_t size,
120 int purge, int one_shot)
122 const struct GNUNET_MessageHeader *hdr;
127 unsigned long offset;
130 GNUNET_assert (mst->off <= mst->pos);
131 GNUNET_assert (mst->pos <= mst->curr_buf);
132 LOG (GNUNET_ERROR_TYPE_DEBUG,
133 "Server-mst receives %u bytes with %u bytes already in private buffer\n",
134 (unsigned int) size, (unsigned int) (mst->pos - mst->off));
136 ibuf = (char *) mst->hdr;
140 GNUNET_assert (mst->pos >= mst->off);
141 if ((mst->curr_buf - mst->off < sizeof (struct GNUNET_MessageHeader)) ||
142 (0 != (mst->off % ALIGN_FACTOR)))
144 /* need to align or need more space */
145 mst->pos -= mst->off;
146 memmove (ibuf, &ibuf[mst->off], mst->pos);
149 if (mst->pos - mst->off < sizeof (struct GNUNET_MessageHeader))
152 GNUNET_MIN (sizeof (struct GNUNET_MessageHeader) -
153 (mst->pos - mst->off), size);
154 memcpy (&ibuf[mst->pos], buf, delta);
159 if (mst->pos - mst->off < sizeof (struct GNUNET_MessageHeader))
168 hdr = (const struct GNUNET_MessageHeader *) &ibuf[mst->off];
169 want = ntohs (hdr->size);
170 if (want < sizeof (struct GNUNET_MessageHeader))
173 return GNUNET_SYSERR;
175 if ( (mst->curr_buf - mst->off < want) &&
178 /* can get more space by moving */
179 mst->pos -= mst->off;
180 memmove (ibuf, &ibuf[mst->off], mst->pos);
183 if (mst->curr_buf < want)
185 /* need to get more space by growing buffer */
186 GNUNET_assert (0 == mst->off);
187 mst->hdr = GNUNET_realloc (mst->hdr, want);
188 ibuf = (char *) mst->hdr;
189 mst->curr_buf = want;
191 hdr = (const struct GNUNET_MessageHeader *) &ibuf[mst->off];
192 if (mst->pos - mst->off < want)
194 delta = GNUNET_MIN (want - (mst->pos - mst->off), size);
195 GNUNET_assert (mst->pos + delta <= mst->curr_buf);
196 memcpy (&ibuf[mst->pos], buf, delta);
201 if (mst->pos - mst->off < want)
210 if (one_shot == GNUNET_SYSERR)
212 /* cannot call callback again, but return value saying that
213 * we have another full message in the buffer */
217 if (one_shot == GNUNET_YES)
218 one_shot = GNUNET_SYSERR;
220 if (GNUNET_SYSERR == mst->cb (mst->cb_cls, client_identity, hdr))
221 return GNUNET_SYSERR;
222 if (mst->off == mst->pos)
224 /* reset to beginning of buffer, it's free right now! */
229 GNUNET_assert (0 == mst->pos);
232 LOG (GNUNET_ERROR_TYPE_DEBUG,
233 "Server-mst has %u bytes left in inbound buffer\n",
234 (unsigned int) size);
235 if (size < sizeof (struct GNUNET_MessageHeader))
237 offset = (unsigned long) buf;
238 need_align = (0 != (offset % ALIGN_FACTOR)) ? GNUNET_YES : GNUNET_NO;
239 if (GNUNET_NO == need_align)
241 /* can try to do zero-copy and process directly from original buffer */
242 hdr = (const struct GNUNET_MessageHeader *) buf;
243 want = ntohs (hdr->size);
244 if (want < sizeof (struct GNUNET_MessageHeader))
248 return GNUNET_SYSERR;
251 break; /* or not: buffer incomplete, so copy to private buffer... */
252 if (one_shot == GNUNET_SYSERR)
254 /* cannot call callback again, but return value saying that
255 * we have another full message in the buffer */
259 if (one_shot == GNUNET_YES)
260 one_shot = GNUNET_SYSERR;
261 if (GNUNET_SYSERR == mst->cb (mst->cb_cls, client_identity, hdr))
262 return GNUNET_SYSERR;
268 /* need to copy to private buffer to align;
269 * yes, we go a bit more spagetti than usual here */
274 if ((size > 0) && (!purge))
276 if (size + mst->pos > mst->curr_buf)
278 mst->hdr = GNUNET_realloc (mst->hdr, size + mst->pos);
279 ibuf = (char *) mst->hdr;
280 mst->curr_buf = size + mst->pos;
282 GNUNET_assert (size + mst->pos <= mst->curr_buf);
283 memcpy (&ibuf[mst->pos], buf, size);
291 LOG (GNUNET_ERROR_TYPE_DEBUG,
292 "Server-mst leaves %u bytes in private buffer\n",
293 (unsigned int) (mst->pos - mst->off));
299 * Destroys a tokenizer.
301 * @param mst tokenizer to destroy
304 GNUNET_SERVER_mst_destroy (struct GNUNET_SERVER_MessageStreamTokenizer *mst)
306 GNUNET_free (mst->hdr);
312 /* end of server_mst.c */