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-rw-r--r--src/lib/util/mst.c411
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diff --git a/src/lib/util/mst.c b/src/lib/util/mst.c
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1/*
2 This file is part of GNUnet.
3 Copyright (C) 2010, 2016, 2017 GNUnet e.V.
4
5 GNUnet is free software: you can redistribute it and/or modify it
6 under the terms of the GNU Affero General Public License as published
7 by the Free Software Foundation, either version 3 of the License,
8 or (at your option) any later version.
9
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 Affero General Public License for more details.
14
15 You should have received a copy of the GNU Affero General Public License
16 along with this program. If not, see <http://www.gnu.org/licenses/>.
17
18 SPDX-License-Identifier: AGPL3.0-or-later
19 */
20
21/**
22 * @file util/mst.c
23 * @brief convenience functions for handling inbound message buffers
24 * @author Christian Grothoff
25 */
26
27
28#include "platform.h"
29#include "gnunet_util_lib.h"
30
31
32#if HAVE_UNALIGNED_64_ACCESS
33#define ALIGN_FACTOR 4
34#else
35#define ALIGN_FACTOR 8
36#endif
37
38#define LOG(kind, ...) GNUNET_log_from (kind, "util-mst", __VA_ARGS__)
39
40
41/**
42 * Handle to a message stream tokenizer.
43 */
44struct GNUNET_MessageStreamTokenizer
45{
46 /**
47 * Function to call on completed messages.
48 */
49 GNUNET_MessageTokenizerCallback cb;
50
51 /**
52 * Closure for @e cb.
53 */
54 void *cb_cls;
55
56 /**
57 * Size of the buffer (starting at @e hdr).
58 */
59 size_t curr_buf;
60
61 /**
62 * How many bytes in buffer have we already processed?
63 */
64 size_t off;
65
66 /**
67 * How many bytes in buffer are valid right now?
68 */
69 size_t pos;
70
71 /**
72 * Beginning of the buffer. Typed like this to force alignment.
73 */
74 struct GNUNET_MessageHeader *hdr;
75};
76
77
78/**
79 * Create a message stream tokenizer.
80 *
81 * @param cb function to call on completed messages
82 * @param cb_cls closure for @a cb
83 * @return handle to tokenizer
84 */
85struct GNUNET_MessageStreamTokenizer *
86GNUNET_MST_create (GNUNET_MessageTokenizerCallback cb,
87 void *cb_cls)
88{
89 struct GNUNET_MessageStreamTokenizer *ret;
90
91 ret = GNUNET_new (struct GNUNET_MessageStreamTokenizer);
92 ret->hdr = GNUNET_malloc (GNUNET_MIN_MESSAGE_SIZE);
93 ret->curr_buf = GNUNET_MIN_MESSAGE_SIZE;
94 ret->cb = cb;
95 ret->cb_cls = cb_cls;
96 return ret;
97}
98
99
100enum GNUNET_GenericReturnValue
101GNUNET_MST_from_buffer (struct GNUNET_MessageStreamTokenizer *mst,
102 const char *buf,
103 size_t size,
104 int purge,
105 int one_shot)
106{
107 const struct GNUNET_MessageHeader *hdr;
108 size_t delta;
109 uint16_t want;
110 char *ibuf;
111 int ret;
112 int cbret;
113
114 GNUNET_assert (mst->off <= mst->pos);
115 GNUNET_assert (mst->pos <= mst->curr_buf);
116 LOG (GNUNET_ERROR_TYPE_DEBUG,
117 "MST receives %u bytes with %u (%u/%u) bytes already in private buffer\n",
118 (unsigned int) size,
119 (unsigned int) (mst->pos - mst->off),
120 (unsigned int) mst->pos,
121 (unsigned int) mst->off);
122 ret = GNUNET_OK;
123 ibuf = (char *) mst->hdr;
124 while (mst->pos > 0)
125 {
126do_align:
127 GNUNET_assert (mst->pos >= mst->off);
128 if ((mst->curr_buf - mst->off < sizeof(struct GNUNET_MessageHeader)) ||
129 (0 != (mst->off % ALIGN_FACTOR)))
130 {
131 /* need to align or need more space */
132 mst->pos -= mst->off;
133 memmove (ibuf,
134 &ibuf[mst->off],
135 mst->pos);
136 mst->off = 0;
137 }
138 if (mst->pos - mst->off < sizeof(struct GNUNET_MessageHeader))
139 {
140 delta
141 = GNUNET_MIN (sizeof(struct GNUNET_MessageHeader)
142 - (mst->pos - mst->off),
143 size);
144 GNUNET_memcpy (&ibuf[mst->pos],
145 buf,
146 delta);
147 mst->pos += delta;
148 buf += delta;
149 size -= delta;
150 }
151 if (mst->pos - mst->off < sizeof(struct GNUNET_MessageHeader))
152 {
153 if (purge)
154 {
155 mst->off = 0;
156 mst->pos = 0;
157 }
158 return GNUNET_OK;
159 }
160 hdr = (const struct GNUNET_MessageHeader *) &ibuf[mst->off];
161 want = ntohs (hdr->size);
162 LOG (GNUNET_ERROR_TYPE_DEBUG,
163 "We want to read message of size %u\n",
164 want);
165 if (want < sizeof(struct GNUNET_MessageHeader))
166 {
167 GNUNET_break_op (0);
168 return GNUNET_SYSERR;
169 }
170 if ((mst->curr_buf - mst->off < want) &&
171 (mst->off > 0))
172 {
173 /* can get more space by moving */
174 mst->pos -= mst->off;
175 memmove (ibuf,
176 &ibuf[mst->off],
177 mst->pos);
178 mst->off = 0;
179 }
180 if (mst->curr_buf < want)
181 {
182 /* need to get more space by growing buffer */
183 GNUNET_assert (0 == mst->off);
184 mst->hdr = GNUNET_realloc (mst->hdr,
185 want);
186 ibuf = (char *) mst->hdr;
187 mst->curr_buf = want;
188 }
189 hdr = (const struct GNUNET_MessageHeader *) &ibuf[mst->off];
190 if (mst->pos - mst->off < want)
191 {
192 delta = GNUNET_MIN (want - (mst->pos - mst->off),
193 size);
194 GNUNET_assert (mst->pos + delta <= mst->curr_buf);
195 GNUNET_memcpy (&ibuf[mst->pos],
196 buf,
197 delta);
198 mst->pos += delta;
199 buf += delta;
200 size -= delta;
201 }
202 if (mst->pos - mst->off < want)
203 {
204 if (purge)
205 {
206 mst->off = 0;
207 mst->pos = 0;
208 }
209 return GNUNET_OK;
210 }
211 if (one_shot == GNUNET_SYSERR)
212 {
213 /* cannot call callback again, but return value saying that
214 * we have another full message in the buffer */
215 ret = GNUNET_NO;
216 goto copy;
217 }
218 if (one_shot == GNUNET_YES)
219 one_shot = GNUNET_SYSERR;
220 mst->off += want;
221 if (GNUNET_OK !=
222 (cbret = mst->cb (mst->cb_cls,
223 hdr)))
224 {
225 if (GNUNET_SYSERR == cbret)
226 GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
227 "Failure processing message of type %u and size %u\n",
228 ntohs (hdr->type),
229 ntohs (hdr->size));
230 return GNUNET_SYSERR;
231 }
232 if (mst->off == mst->pos)
233 {
234 /* reset to beginning of buffer, it's free right now! */
235 mst->off = 0;
236 mst->pos = 0;
237 }
238 }
239 GNUNET_assert (0 == mst->pos);
240 while (size > 0)
241 {
242 unsigned long offset = (unsigned long) buf;
243 bool need_align = (0 != (offset % ALIGN_FACTOR));
244
245 LOG (GNUNET_ERROR_TYPE_DEBUG,
246 "Server-mst has %u bytes left in inbound buffer\n",
247 (unsigned int) size);
248 if (size < sizeof(struct GNUNET_MessageHeader))
249 break;
250 if (! need_align)
251 {
252 /* can try to do zero-copy and process directly from original buffer */
253 hdr = (const struct GNUNET_MessageHeader *) buf;
254 want = ntohs (hdr->size);
255 if (want < sizeof(struct GNUNET_MessageHeader))
256 {
257 GNUNET_break_op (0);
258 mst->off = 0;
259 return GNUNET_SYSERR;
260 }
261 if (size < want)
262 break; /* or not: buffer incomplete, so copy to private buffer... */
263 if (one_shot == GNUNET_SYSERR)
264 {
265 /* cannot call callback again, but return value saying that
266 * we have another full message in the buffer */
267 ret = GNUNET_NO;
268 goto copy;
269 }
270 if (GNUNET_YES == one_shot)
271 one_shot = GNUNET_SYSERR;
272 if (GNUNET_OK !=
273 (cbret = mst->cb (mst->cb_cls,
274 hdr)))
275 {
276 if (GNUNET_SYSERR == cbret)
277 GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
278 "Failure processing message of type %u and size %u\n",
279 ntohs (hdr->type),
280 ntohs (hdr->size));
281 return GNUNET_SYSERR;
282 }
283 buf += want;
284 size -= want;
285 }
286 else
287 {
288 /* need to copy to private buffer to align;
289 * yes, we go a bit more spaghetti than usual here */
290 goto do_align;
291 }
292 }
293copy:
294 if ((size > 0) && (! purge))
295 {
296 if (size + mst->pos > mst->curr_buf)
297 {
298 mst->hdr = GNUNET_realloc (mst->hdr,
299 size + mst->pos);
300 ibuf = (char *) mst->hdr;
301 mst->curr_buf = size + mst->pos;
302 }
303 GNUNET_assert (size + mst->pos <= mst->curr_buf);
304 GNUNET_memcpy (&ibuf[mst->pos],
305 buf,
306 size);
307 mst->pos += size;
308 }
309 if (purge)
310 {
311 mst->off = 0;
312 mst->pos = 0;
313 }
314 LOG (GNUNET_ERROR_TYPE_DEBUG,
315 "Server-mst leaves %u (%u/%u) bytes in private buffer\n",
316 (unsigned int) (mst->pos - mst->off),
317 (unsigned int) mst->pos,
318 (unsigned int) mst->off);
319 return ret;
320}
321
322
323/**
324 * Add incoming data to the receive buffer and call the
325 * callback for all complete messages.
326 *
327 * @param mst tokenizer to use
328 * @param buf input data to add
329 * @param size number of bytes in @a buf
330 * @param purge should any excess bytes in the buffer be discarded
331 * (i.e. for packet-based services like UDP)
332 * @param one_shot only call callback once, keep rest of message in buffer
333 * @return #GNUNET_OK if we are done processing (need more data)
334 * #GNUNET_NO if one_shot was set and we have another message ready
335 * #GNUNET_SYSERR if the data stream is corrupt
336 */
337enum GNUNET_GenericReturnValue
338GNUNET_MST_read (struct GNUNET_MessageStreamTokenizer *mst,
339 struct GNUNET_NETWORK_Handle *sock,
340 int purge,
341 int one_shot)
342{
343 ssize_t ret;
344 size_t left;
345 char *buf;
346
347 left = mst->curr_buf - mst->pos;
348 buf = (char *) mst->hdr;
349 ret = GNUNET_NETWORK_socket_recv (sock,
350 &buf[mst->pos],
351 left);
352 if (-1 == ret)
353 {
354 if ((EAGAIN == errno) ||
355 (EINTR == errno))
356 return GNUNET_OK;
357 GNUNET_log_strerror (GNUNET_ERROR_TYPE_INFO,
358 "recv");
359 return GNUNET_SYSERR;
360 }
361 if (0 == ret)
362 {
363 /* other side closed connection, treat as error */
364 return GNUNET_SYSERR;
365 }
366 mst->pos += ret;
367 return GNUNET_MST_from_buffer (mst,
368 NULL,
369 0,
370 purge,
371 one_shot);
372}
373
374
375/**
376 * Obtain the next message from the @a mst, assuming that
377 * there are more unprocessed messages in the internal buffer
378 * of the @a mst.
379 *
380 * @param mst tokenizer to use
381 * @param one_shot only call callback once, keep rest of message in buffer
382 * @return #GNUNET_OK if we are done processing (need more data)
383 * #GNUNET_NO if one_shot was set and we have another message ready
384 * #GNUNET_SYSERR if the data stream is corrupt
385 */
386enum GNUNET_GenericReturnValue
387GNUNET_MST_next (struct GNUNET_MessageStreamTokenizer *mst,
388 int one_shot)
389{
390 return GNUNET_MST_from_buffer (mst,
391 NULL,
392 0,
393 GNUNET_NO,
394 one_shot);
395}
396
397
398/**
399 * Destroys a tokenizer.
400 *
401 * @param mst tokenizer to destroy
402 */
403void
404GNUNET_MST_destroy (struct GNUNET_MessageStreamTokenizer *mst)
405{
406 GNUNET_free (mst->hdr);
407 GNUNET_free (mst);
408}
409
410
411/* end of server_mst.c */
generated by cgit v1.2.3 (git 2.39.1) at 2024-05-05 09:39:58 +0000