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[DCCP]: Move the ack vector code to net/dccp/ackvec.[ch]
[deliverable/linux.git] / net / dccp / options.c
1 /*
2 * net/dccp/options.c
3 *
4 * An implementation of the DCCP protocol
5 * Copyright (c) 2005 Aristeu Sergio Rozanski Filho <aris@cathedrallabs.org>
6 * Copyright (c) 2005 Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
7 * Copyright (c) 2005 Ian McDonald <iam4@cs.waikato.ac.nz>
8 *
9 * This program is free software; you can redistribute it and/or
10 * modify it under the terms of the GNU General Public License
11 * as published by the Free Software Foundation; either version
12 * 2 of the License, or (at your option) any later version.
13 */
14 #include <linux/config.h>
15 #include <linux/dccp.h>
16 #include <linux/module.h>
17 #include <linux/types.h>
18 #include <linux/kernel.h>
19 #include <linux/skbuff.h>
20
21 #include "ackvec.h"
22 #include "ccid.h"
23 #include "dccp.h"
24
25 /* stores the default values for new connection. may be changed with sysctl */
26 static const struct dccp_options dccpo_default_values = {
27 .dccpo_sequence_window = DCCPF_INITIAL_SEQUENCE_WINDOW,
28 .dccpo_ccid = DCCPF_INITIAL_CCID,
29 .dccpo_send_ack_vector = DCCPF_INITIAL_SEND_ACK_VECTOR,
30 .dccpo_send_ndp_count = DCCPF_INITIAL_SEND_NDP_COUNT,
31 };
32
33 void dccp_options_init(struct dccp_options *dccpo)
34 {
35 memcpy(dccpo, &dccpo_default_values, sizeof(*dccpo));
36 }
37
38 static u32 dccp_decode_value_var(const unsigned char *bf, const u8 len)
39 {
40 u32 value = 0;
41
42 if (len > 3)
43 value += *bf++ << 24;
44 if (len > 2)
45 value += *bf++ << 16;
46 if (len > 1)
47 value += *bf++ << 8;
48 if (len > 0)
49 value += *bf;
50
51 return value;
52 }
53
54 int dccp_parse_options(struct sock *sk, struct sk_buff *skb)
55 {
56 struct dccp_sock *dp = dccp_sk(sk);
57 #ifdef CONFIG_IP_DCCP_DEBUG
58 const char *debug_prefix = dp->dccps_role == DCCP_ROLE_CLIENT ?
59 "CLIENT rx opt: " : "server rx opt: ";
60 #endif
61 const struct dccp_hdr *dh = dccp_hdr(skb);
62 const u8 pkt_type = DCCP_SKB_CB(skb)->dccpd_type;
63 unsigned char *options = (unsigned char *)dh + dccp_hdr_len(skb);
64 unsigned char *opt_ptr = options;
65 const unsigned char *opt_end = (unsigned char *)dh +
66 (dh->dccph_doff * 4);
67 struct dccp_options_received *opt_recv = &dp->dccps_options_received;
68 unsigned char opt, len;
69 unsigned char *value;
70 u32 elapsed_time;
71
72 memset(opt_recv, 0, sizeof(*opt_recv));
73
74 while (opt_ptr != opt_end) {
75 opt = *opt_ptr++;
76 len = 0;
77 value = NULL;
78
79 /* Check if this isn't a single byte option */
80 if (opt > DCCPO_MAX_RESERVED) {
81 if (opt_ptr == opt_end)
82 goto out_invalid_option;
83
84 len = *opt_ptr++;
85 if (len < 3)
86 goto out_invalid_option;
87 /*
88 * Remove the type and len fields, leaving
89 * just the value size
90 */
91 len -= 2;
92 value = opt_ptr;
93 opt_ptr += len;
94
95 if (opt_ptr > opt_end)
96 goto out_invalid_option;
97 }
98
99 switch (opt) {
100 case DCCPO_PADDING:
101 break;
102 case DCCPO_NDP_COUNT:
103 if (len > 3)
104 goto out_invalid_option;
105
106 opt_recv->dccpor_ndp = dccp_decode_value_var(value, len);
107 dccp_pr_debug("%sNDP count=%d\n", debug_prefix,
108 opt_recv->dccpor_ndp);
109 break;
110 case DCCPO_ACK_VECTOR_0:
111 case DCCPO_ACK_VECTOR_1:
112 if (pkt_type == DCCP_PKT_DATA)
113 continue;
114
115 if (dp->dccps_options.dccpo_send_ack_vector &&
116 dccp_ackvec_parse(sk, skb, opt, value, len))
117 goto out_invalid_option;
118 break;
119 case DCCPO_TIMESTAMP:
120 if (len != 4)
121 goto out_invalid_option;
122
123 opt_recv->dccpor_timestamp = ntohl(*(u32 *)value);
124
125 dp->dccps_timestamp_echo = opt_recv->dccpor_timestamp;
126 dccp_timestamp(sk, &dp->dccps_timestamp_time);
127
128 dccp_pr_debug("%sTIMESTAMP=%u, ackno=%llu\n",
129 debug_prefix, opt_recv->dccpor_timestamp,
130 (unsigned long long)
131 DCCP_SKB_CB(skb)->dccpd_ack_seq);
132 break;
133 case DCCPO_TIMESTAMP_ECHO:
134 if (len != 4 && len != 6 && len != 8)
135 goto out_invalid_option;
136
137 opt_recv->dccpor_timestamp_echo = ntohl(*(u32 *)value);
138
139 dccp_pr_debug("%sTIMESTAMP_ECHO=%u, len=%d, ackno=%llu, ",
140 debug_prefix,
141 opt_recv->dccpor_timestamp_echo,
142 len + 2,
143 (unsigned long long)
144 DCCP_SKB_CB(skb)->dccpd_ack_seq);
145
146
147 if (len == 4)
148 break;
149
150 if (len == 6)
151 elapsed_time = ntohs(*(u16 *)(value + 4));
152 else
153 elapsed_time = ntohl(*(u32 *)(value + 4));
154
155 /* Give precedence to the biggest ELAPSED_TIME */
156 if (elapsed_time > opt_recv->dccpor_elapsed_time)
157 opt_recv->dccpor_elapsed_time = elapsed_time;
158 break;
159 case DCCPO_ELAPSED_TIME:
160 if (len != 2 && len != 4)
161 goto out_invalid_option;
162
163 if (pkt_type == DCCP_PKT_DATA)
164 continue;
165
166 if (len == 2)
167 elapsed_time = ntohs(*(u16 *)value);
168 else
169 elapsed_time = ntohl(*(u32 *)value);
170
171 if (elapsed_time > opt_recv->dccpor_elapsed_time)
172 opt_recv->dccpor_elapsed_time = elapsed_time;
173
174 dccp_pr_debug("%sELAPSED_TIME=%d\n", debug_prefix,
175 elapsed_time);
176 break;
177 /*
178 * From draft-ietf-dccp-spec-11.txt:
179 *
180 * Option numbers 128 through 191 are for
181 * options sent from the HC-Sender to the
182 * HC-Receiver; option numbers 192 through 255
183 * are for options sent from the HC-Receiver to
184 * the HC-Sender.
185 */
186 case 128 ... 191: {
187 const u16 idx = value - options;
188
189 if (ccid_hc_rx_parse_options(dp->dccps_hc_rx_ccid, sk,
190 opt, len, idx,
191 value) != 0)
192 goto out_invalid_option;
193 }
194 break;
195 case 192 ... 255: {
196 const u16 idx = value - options;
197
198 if (ccid_hc_tx_parse_options(dp->dccps_hc_tx_ccid, sk,
199 opt, len, idx,
200 value) != 0)
201 goto out_invalid_option;
202 }
203 break;
204 default:
205 pr_info("DCCP(%p): option %d(len=%d) not "
206 "implemented, ignoring\n",
207 sk, opt, len);
208 break;
209 }
210 }
211
212 return 0;
213
214 out_invalid_option:
215 DCCP_INC_STATS_BH(DCCP_MIB_INVALIDOPT);
216 DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_OPTION_ERROR;
217 pr_info("DCCP(%p): invalid option %d, len=%d\n", sk, opt, len);
218 return -1;
219 }
220
221 static void dccp_encode_value_var(const u32 value, unsigned char *to,
222 const unsigned int len)
223 {
224 if (len > 3)
225 *to++ = (value & 0xFF000000) >> 24;
226 if (len > 2)
227 *to++ = (value & 0xFF0000) >> 16;
228 if (len > 1)
229 *to++ = (value & 0xFF00) >> 8;
230 if (len > 0)
231 *to++ = (value & 0xFF);
232 }
233
234 static inline int dccp_ndp_len(const int ndp)
235 {
236 return likely(ndp <= 0xFF) ? 1 : ndp <= 0xFFFF ? 2 : 3;
237 }
238
239 void dccp_insert_option(struct sock *sk, struct sk_buff *skb,
240 const unsigned char option,
241 const void *value, const unsigned char len)
242 {
243 unsigned char *to;
244
245 if (DCCP_SKB_CB(skb)->dccpd_opt_len + len + 2 > DCCP_MAX_OPT_LEN) {
246 LIMIT_NETDEBUG(KERN_INFO "DCCP: packet too small to insert "
247 "%d option!\n", option);
248 return;
249 }
250
251 DCCP_SKB_CB(skb)->dccpd_opt_len += len + 2;
252
253 to = skb_push(skb, len + 2);
254 *to++ = option;
255 *to++ = len + 2;
256
257 memcpy(to, value, len);
258 }
259
260 EXPORT_SYMBOL_GPL(dccp_insert_option);
261
262 static void dccp_insert_option_ndp(struct sock *sk, struct sk_buff *skb)
263 {
264 struct dccp_sock *dp = dccp_sk(sk);
265 int ndp = dp->dccps_ndp_count;
266
267 if (dccp_non_data_packet(skb))
268 ++dp->dccps_ndp_count;
269 else
270 dp->dccps_ndp_count = 0;
271
272 if (ndp > 0) {
273 unsigned char *ptr;
274 const int ndp_len = dccp_ndp_len(ndp);
275 const int len = ndp_len + 2;
276
277 if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN)
278 return;
279
280 DCCP_SKB_CB(skb)->dccpd_opt_len += len;
281
282 ptr = skb_push(skb, len);
283 *ptr++ = DCCPO_NDP_COUNT;
284 *ptr++ = len;
285 dccp_encode_value_var(ndp, ptr, ndp_len);
286 }
287 }
288
289 static inline int dccp_elapsed_time_len(const u32 elapsed_time)
290 {
291 return elapsed_time == 0 ? 0 : elapsed_time <= 0xFFFF ? 2 : 4;
292 }
293
294 void dccp_insert_option_elapsed_time(struct sock *sk,
295 struct sk_buff *skb,
296 u32 elapsed_time)
297 {
298 #ifdef CONFIG_IP_DCCP_DEBUG
299 struct dccp_sock *dp = dccp_sk(sk);
300 const char *debug_prefix = dp->dccps_role == DCCP_ROLE_CLIENT ?
301 "CLIENT TX opt: " : "server TX opt: ";
302 #endif
303 const int elapsed_time_len = dccp_elapsed_time_len(elapsed_time);
304 const int len = 2 + elapsed_time_len;
305 unsigned char *to;
306
307 if (elapsed_time_len == 0)
308 return;
309
310 if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN) {
311 LIMIT_NETDEBUG(KERN_INFO "DCCP: packet too small to "
312 "insert elapsed time!\n");
313 return;
314 }
315
316 DCCP_SKB_CB(skb)->dccpd_opt_len += len;
317
318 to = skb_push(skb, len);
319 *to++ = DCCPO_ELAPSED_TIME;
320 *to++ = len;
321
322 if (elapsed_time_len == 2) {
323 const u16 var16 = htons((u16)elapsed_time);
324 memcpy(to, &var16, 2);
325 } else {
326 const u32 var32 = htonl(elapsed_time);
327 memcpy(to, &var32, 4);
328 }
329
330 dccp_pr_debug("%sELAPSED_TIME=%u, len=%d, seqno=%llu\n",
331 debug_prefix, elapsed_time,
332 len,
333 (unsigned long long) DCCP_SKB_CB(skb)->dccpd_seq);
334 }
335
336 EXPORT_SYMBOL_GPL(dccp_insert_option_elapsed_time);
337
338 void dccp_timestamp(const struct sock *sk, struct timeval *tv)
339 {
340 const struct dccp_sock *dp = dccp_sk(sk);
341
342 do_gettimeofday(tv);
343 tv->tv_sec -= dp->dccps_epoch.tv_sec;
344 tv->tv_usec -= dp->dccps_epoch.tv_usec;
345
346 while (tv->tv_usec < 0) {
347 tv->tv_sec--;
348 tv->tv_usec += USEC_PER_SEC;
349 }
350 }
351
352 EXPORT_SYMBOL_GPL(dccp_timestamp);
353
354 void dccp_insert_option_timestamp(struct sock *sk, struct sk_buff *skb)
355 {
356 struct timeval tv;
357 u32 now;
358
359 dccp_timestamp(sk, &tv);
360 now = timeval_usecs(&tv) / 10;
361 /* yes this will overflow but that is the point as we want a
362 * 10 usec 32 bit timer which mean it wraps every 11.9 hours */
363
364 now = htonl(now);
365 dccp_insert_option(sk, skb, DCCPO_TIMESTAMP, &now, sizeof(now));
366 }
367
368 EXPORT_SYMBOL_GPL(dccp_insert_option_timestamp);
369
370 static void dccp_insert_option_timestamp_echo(struct sock *sk,
371 struct sk_buff *skb)
372 {
373 struct dccp_sock *dp = dccp_sk(sk);
374 #ifdef CONFIG_IP_DCCP_DEBUG
375 const char *debug_prefix = dp->dccps_role == DCCP_ROLE_CLIENT ?
376 "CLIENT TX opt: " : "server TX opt: ";
377 #endif
378 struct timeval now;
379 u32 tstamp_echo;
380 u32 elapsed_time;
381 int len, elapsed_time_len;
382 unsigned char *to;
383
384 dccp_timestamp(sk, &now);
385 elapsed_time = timeval_delta(&now, &dp->dccps_timestamp_time) / 10;
386 elapsed_time_len = dccp_elapsed_time_len(elapsed_time);
387 len = 6 + elapsed_time_len;
388
389 if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN) {
390 LIMIT_NETDEBUG(KERN_INFO "DCCP: packet too small to insert "
391 "timestamp echo!\n");
392 return;
393 }
394
395 DCCP_SKB_CB(skb)->dccpd_opt_len += len;
396
397 to = skb_push(skb, len);
398 *to++ = DCCPO_TIMESTAMP_ECHO;
399 *to++ = len;
400
401 tstamp_echo = htonl(dp->dccps_timestamp_echo);
402 memcpy(to, &tstamp_echo, 4);
403 to += 4;
404
405 if (elapsed_time_len == 2) {
406 const u16 var16 = htons((u16)elapsed_time);
407 memcpy(to, &var16, 2);
408 } else if (elapsed_time_len == 4) {
409 const u32 var32 = htonl(elapsed_time);
410 memcpy(to, &var32, 4);
411 }
412
413 dccp_pr_debug("%sTIMESTAMP_ECHO=%u, len=%d, seqno=%llu\n",
414 debug_prefix, dp->dccps_timestamp_echo,
415 len,
416 (unsigned long long) DCCP_SKB_CB(skb)->dccpd_seq);
417
418 dp->dccps_timestamp_echo = 0;
419 dp->dccps_timestamp_time.tv_sec = 0;
420 dp->dccps_timestamp_time.tv_usec = 0;
421 }
422
423 void dccp_insert_options(struct sock *sk, struct sk_buff *skb)
424 {
425 struct dccp_sock *dp = dccp_sk(sk);
426
427 DCCP_SKB_CB(skb)->dccpd_opt_len = 0;
428
429 if (dp->dccps_options.dccpo_send_ndp_count)
430 dccp_insert_option_ndp(sk, skb);
431
432 if (!dccp_packet_without_ack(skb)) {
433 if (dp->dccps_options.dccpo_send_ack_vector &&
434 dccp_ackvec_pending(dp->dccps_hc_rx_ackvec))
435 dccp_insert_option_ackvec(sk, skb);
436 if (dp->dccps_timestamp_echo != 0)
437 dccp_insert_option_timestamp_echo(sk, skb);
438 }
439
440 if (dp->dccps_hc_rx_insert_options) {
441 ccid_hc_rx_insert_options(dp->dccps_hc_rx_ccid, sk, skb);
442 dp->dccps_hc_rx_insert_options = 0;
443 }
444 if (dp->dccps_hc_tx_insert_options) {
445 ccid_hc_tx_insert_options(dp->dccps_hc_tx_ccid, sk, skb);
446 dp->dccps_hc_tx_insert_options = 0;
447 }
448
449 /* XXX: insert other options when appropriate */
450
451 if (DCCP_SKB_CB(skb)->dccpd_opt_len != 0) {
452 /* The length of all options has to be a multiple of 4 */
453 int padding = DCCP_SKB_CB(skb)->dccpd_opt_len % 4;
454
455 if (padding != 0) {
456 padding = 4 - padding;
457 memset(skb_push(skb, padding), 0, padding);
458 DCCP_SKB_CB(skb)->dccpd_opt_len += padding;
459 }
460 }
461 }
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