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.
10 GNUnet is distributed in the hope that it will be useful, but
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 cb function to call on completed messages
87 * @param cb_cls closure for cb
88 * @return handle to tokenizer
90 struct GNUNET_SERVER_MessageStreamTokenizer *
91 GNUNET_SERVER_mst_create (GNUNET_SERVER_MessageTokenizerCallback cb,
94 struct GNUNET_SERVER_MessageStreamTokenizer *ret;
96 ret = GNUNET_malloc (sizeof (struct GNUNET_SERVER_MessageStreamTokenizer));
97 ret->hdr = GNUNET_malloc (GNUNET_SERVER_MIN_BUFFER_SIZE);
98 ret->curr_buf = GNUNET_SERVER_MIN_BUFFER_SIZE;
100 ret->cb_cls = cb_cls;
106 * Add incoming data to the receive buffer and call the
107 * callback for all complete messages.
109 * @param mst tokenizer to use
110 * @param client_identity ID of client for which this is a buffer
111 * @param buf input data to add
112 * @param size number of bytes in buf
113 * @param purge should any excess bytes in the buffer be discarded
114 * (i.e. for packet-based services like UDP)
115 * @param one_shot only call callback once, keep rest of message in buffer
116 * @return GNUNET_OK if we are done processing (need more data)
117 * GNUNET_NO if one_shot was set and we have another message ready
118 * GNUNET_SYSERR if the data stream is corrupt
121 GNUNET_SERVER_mst_receive (struct GNUNET_SERVER_MessageStreamTokenizer *mst,
122 void *client_identity, const char *buf, size_t size,
123 int purge, int one_shot)
125 const struct GNUNET_MessageHeader *hdr;
130 unsigned long offset;
134 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
135 "Server-mst receives %u bytes with %u bytes already in private buffer\n",
136 (unsigned int) size, (unsigned int) (mst->pos - mst->off));
139 ibuf = (char *) mst->hdr;
143 if ((mst->curr_buf - mst->off < sizeof (struct GNUNET_MessageHeader)) ||
144 (0 != (mst->off % ALIGN_FACTOR)))
146 /* need to align or need more space */
147 mst->pos -= mst->off;
148 memmove (ibuf, &ibuf[mst->off], mst->pos);
151 if (mst->pos - mst->off < sizeof (struct GNUNET_MessageHeader))
154 GNUNET_MIN (sizeof (struct GNUNET_MessageHeader) -
155 (mst->pos - mst->off), size);
156 memcpy (&ibuf[mst->pos], buf, delta);
161 if (mst->pos - mst->off < sizeof (struct GNUNET_MessageHeader))
170 hdr = (const struct GNUNET_MessageHeader *) &ibuf[mst->off];
171 want = ntohs (hdr->size);
172 if (want < sizeof (struct GNUNET_MessageHeader))
175 return GNUNET_SYSERR;
177 if (mst->curr_buf - mst->off < want)
179 /* need more space */
180 mst->pos -= mst->off;
181 memmove (ibuf, &ibuf[mst->off], mst->pos);
184 if (want > mst->curr_buf)
186 mst->hdr = GNUNET_realloc (mst->hdr, want);
187 ibuf = (char *) mst->hdr;
188 mst->curr_buf = want;
190 hdr = (const struct GNUNET_MessageHeader *) &ibuf[mst->off];
191 if (mst->pos - mst->off < want)
193 delta = GNUNET_MIN (want - (mst->pos - mst->off), size);
194 memcpy (&ibuf[mst->pos], buf, delta);
199 if (mst->pos - mst->off < want)
208 if (one_shot == GNUNET_SYSERR)
210 /* cannot call callback again, but return value saying that
211 * we have another full message in the buffer */
215 if (one_shot == GNUNET_YES)
216 one_shot = GNUNET_SYSERR;
217 mst->cb (mst->cb_cls, client_identity, hdr);
219 if (mst->off == mst->pos)
221 /* reset to beginning of buffer, it's free right now! */
229 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
230 "Server-mst has %u bytes left in inbound buffer\n",
231 (unsigned int) size);
233 if (size < sizeof (struct GNUNET_MessageHeader))
235 offset = (unsigned long) buf;
236 need_align = (0 != offset % ALIGN_FACTOR) ? GNUNET_YES : GNUNET_NO;
237 if (GNUNET_NO == need_align)
239 /* can try to do zero-copy and process directly from original buffer */
240 hdr = (const struct GNUNET_MessageHeader *) buf;
241 want = ntohs (hdr->size);
242 if (want < sizeof (struct GNUNET_MessageHeader))
246 return GNUNET_SYSERR;
249 break; /* or not, buffer incomplete, so copy to private buffer... */
250 if (one_shot == GNUNET_SYSERR)
252 /* cannot call callback again, but return value saying that
253 * we have another full message in the buffer */
257 if (one_shot == GNUNET_YES)
258 one_shot = GNUNET_SYSERR;
259 mst->cb (mst->cb_cls, client_identity, hdr);
265 /* need to copy to private buffer to align;
266 * yes, we go a bit more spagetti than usual here */
271 if ((size > 0) && (!purge))
273 if (size + mst->pos > mst->curr_buf)
275 mst->hdr = GNUNET_realloc (mst->hdr, size + mst->pos);
276 ibuf = (char *) mst->hdr;
277 mst->curr_buf = size + mst->pos;
279 GNUNET_assert (mst->pos + size <= mst->curr_buf);
280 memcpy (&ibuf[mst->pos], buf, size);
286 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
287 "Server-mst leaves %u bytes in private buffer\n",
288 (unsigned int) (mst->pos - mst->off));
295 * Destroys a tokenizer.
297 * @param mst tokenizer to destroy
300 GNUNET_SERVER_mst_destroy (struct GNUNET_SERVER_MessageStreamTokenizer *mst)
302 GNUNET_free (mst->hdr);
308 /* end of server_mst.c */