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dccp: Processing Confirm options
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / net / dccp / options.c
blobdebb1008c7adfb24b8162fd4d679e417e3c41d67
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 <ian.mcdonald@jandi.co.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/dccp.h>
15 #include <linux/module.h>
16 #include <linux/types.h>
17 #include <asm/unaligned.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 #include "feat.h"
25
26 int sysctl_dccp_feat_sequence_window = DCCPF_INITIAL_SEQUENCE_WINDOW;
27 int sysctl_dccp_feat_rx_ccid = DCCPF_INITIAL_CCID;
28 int sysctl_dccp_feat_tx_ccid = DCCPF_INITIAL_CCID;
29 int sysctl_dccp_feat_send_ack_vector = DCCPF_INITIAL_SEND_ACK_VECTOR;
30 int sysctl_dccp_feat_send_ndp_count = DCCPF_INITIAL_SEND_NDP_COUNT;
31
32 u64 dccp_decode_value_var(const u8 *bf, const u8 len)
33 {
34 u64 value = 0;
35
36 if (len >= DCCP_OPTVAL_MAXLEN)
37 value += ((u64)*bf++) << 40;
38 if (len > 4)
39 value += ((u64)*bf++) << 32;
40 if (len > 3)
41 value += ((u64)*bf++) << 24;
42 if (len > 2)
43 value += ((u64)*bf++) << 16;
44 if (len > 1)
45 value += ((u64)*bf++) << 8;
46 if (len > 0)
47 value += *bf;
48
49 return value;
50 }
51
52 /**
53 * dccp_parse_options - Parse DCCP options present in @skb
54 * @sk: client|server|listening dccp socket (when @dreq != NULL)
55 * @dreq: request socket to use during connection setup, or NULL
56 */
57 int dccp_parse_options(struct sock *sk, struct dccp_request_sock *dreq,
58 struct sk_buff *skb)
59 {
60 struct dccp_sock *dp = dccp_sk(sk);
61 const struct dccp_hdr *dh = dccp_hdr(skb);
62 const u8 pkt_type = DCCP_SKB_CB(skb)->dccpd_type;
63 u64 ackno = DCCP_SKB_CB(skb)->dccpd_ack_seq;
64 unsigned char *options = (unsigned char *)dh + dccp_hdr_len(skb);
65 unsigned char *opt_ptr = options;
66 const unsigned char *opt_end = (unsigned char *)dh +
67 (dh->dccph_doff * 4);
68 struct dccp_options_received *opt_recv = &dp->dccps_options_received;
69 unsigned char opt, len;
70 unsigned char *uninitialized_var(value);
71 u32 elapsed_time;
72 __be32 opt_val;
73 int rc;
74 int mandatory = 0;
75
76 memset(opt_recv, 0, sizeof(*opt_recv));
77
78 opt = len = 0;
79 while (opt_ptr != opt_end) {
80 opt = *opt_ptr++;
81 len = 0;
82 value = NULL;
83
84 /* Check if this isn't a single byte option */
85 if (opt > DCCPO_MAX_RESERVED) {
86 if (opt_ptr == opt_end)
87 goto out_nonsensical_length;
88
89 len = *opt_ptr++;
90 if (len < 2)
91 goto out_nonsensical_length;
92 /*
93 * Remove the type and len fields, leaving
94 * just the value size
95 */
96 len -= 2;
97 value = opt_ptr;
98 opt_ptr += len;
99
100 if (opt_ptr > opt_end)
101 goto out_nonsensical_length;
102 }
103
104 /*
105 * CCID-Specific Options (from RFC 4340, sec. 10.3):
106 *
107 * Option numbers 128 through 191 are for options sent from the
108 * HC-Sender to the HC-Receiver; option numbers 192 through 255
109 * are for options sent from the HC-Receiver to the HC-Sender.
110 *
111 * CCID-specific options are ignored during connection setup, as
112 * negotiation may still be in progress (see RFC 4340, 10.3).
113 * The same applies to Ack Vectors, as these depend on the CCID.
114 *
115 */
116 if (dreq != NULL && (opt >= 128 ||
117 opt == DCCPO_ACK_VECTOR_0 || opt == DCCPO_ACK_VECTOR_1))
118 goto ignore_option;
119
120 switch (opt) {
121 case DCCPO_PADDING:
122 break;
123 case DCCPO_MANDATORY:
124 if (mandatory)
125 goto out_invalid_option;
126 if (pkt_type != DCCP_PKT_DATA)
127 mandatory = 1;
128 break;
129 case DCCPO_NDP_COUNT:
130 if (len > 6)
131 goto out_invalid_option;
132
133 opt_recv->dccpor_ndp = dccp_decode_value_var(value, len);
134 dccp_pr_debug("%s opt: NDP count=%llu\n", dccp_role(sk),
135 (unsigned long long)opt_recv->dccpor_ndp);
136 break;
137 case DCCPO_CHANGE_L ... DCCPO_CONFIRM_R:
138 if (pkt_type == DCCP_PKT_DATA) /* RFC 4340, 6 */
139 break;
140 rc = dccp_feat_parse_options(sk, dreq, mandatory, opt,
141 *value, value + 1, len - 1);
142 if (rc)
143 goto out_featneg_failed;
144 break;
145 case DCCPO_ACK_VECTOR_0:
146 case DCCPO_ACK_VECTOR_1:
147 if (dccp_packet_without_ack(skb)) /* RFC 4340, 11.4 */
148 break;
149
150 if (dccp_msk(sk)->dccpms_send_ack_vector &&
151 dccp_ackvec_parse(sk, skb, &ackno, opt, value, len))
152 goto out_invalid_option;
153 break;
154 case DCCPO_TIMESTAMP:
155 if (len != 4)
156 goto out_invalid_option;
157 /*
158 * RFC 4340 13.1: "The precise time corresponding to
159 * Timestamp Value zero is not specified". We use
160 * zero to indicate absence of a meaningful timestamp.
161 */
162 opt_val = get_unaligned((__be32 *)value);
163 if (unlikely(opt_val == 0)) {
164 DCCP_WARN("Timestamp with zero value\n");
165 break;
166 }
167
168 if (dreq != NULL) {
169 dreq->dreq_timestamp_echo = ntohl(opt_val);
170 dreq->dreq_timestamp_time = dccp_timestamp();
171 } else {
172 opt_recv->dccpor_timestamp =
173 dp->dccps_timestamp_echo = ntohl(opt_val);
174 dp->dccps_timestamp_time = dccp_timestamp();
175 }
176 dccp_pr_debug("%s rx opt: TIMESTAMP=%u, ackno=%llu\n",
177 dccp_role(sk), ntohl(opt_val),
178 (unsigned long long)
179 DCCP_SKB_CB(skb)->dccpd_ack_seq);
180 break;
181 case DCCPO_TIMESTAMP_ECHO:
182 if (len != 4 && len != 6 && len != 8)
183 goto out_invalid_option;
184
185 opt_val = get_unaligned((__be32 *)value);
186 opt_recv->dccpor_timestamp_echo = ntohl(opt_val);
187
188 dccp_pr_debug("%s rx opt: TIMESTAMP_ECHO=%u, len=%d, "
189 "ackno=%llu", dccp_role(sk),
190 opt_recv->dccpor_timestamp_echo,
191 len + 2,
192 (unsigned long long)
193 DCCP_SKB_CB(skb)->dccpd_ack_seq);
194
195 value += 4;
196
197 if (len == 4) { /* no elapsed time included */
198 dccp_pr_debug_cat("\n");
199 break;
200 }
201
202 if (len == 6) { /* 2-byte elapsed time */
203 __be16 opt_val2 = get_unaligned((__be16 *)value);
204 elapsed_time = ntohs(opt_val2);
205 } else { /* 4-byte elapsed time */
206 opt_val = get_unaligned((__be32 *)value);
207 elapsed_time = ntohl(opt_val);
208 }
209
210 dccp_pr_debug_cat(", ELAPSED_TIME=%u\n", elapsed_time);
211
212 /* Give precedence to the biggest ELAPSED_TIME */
213 if (elapsed_time > opt_recv->dccpor_elapsed_time)
214 opt_recv->dccpor_elapsed_time = elapsed_time;
215 break;
216 case DCCPO_ELAPSED_TIME:
217 if (dccp_packet_without_ack(skb)) /* RFC 4340, 13.2 */
218 break;
219
220 if (len == 2) {
221 __be16 opt_val2 = get_unaligned((__be16 *)value);
222 elapsed_time = ntohs(opt_val2);
223 } else if (len == 4) {
224 opt_val = get_unaligned((__be32 *)value);
225 elapsed_time = ntohl(opt_val);
226 } else {
227 goto out_invalid_option;
228 }
229
230 if (elapsed_time > opt_recv->dccpor_elapsed_time)
231 opt_recv->dccpor_elapsed_time = elapsed_time;
232
233 dccp_pr_debug("%s rx opt: ELAPSED_TIME=%d\n",
234 dccp_role(sk), elapsed_time);
235 break;
236 case 128 ... 191: {
237 const u16 idx = value - options;
238
239 if (ccid_hc_rx_parse_options(dp->dccps_hc_rx_ccid, sk,
240 opt, len, idx,
241 value) != 0)
242 goto out_invalid_option;
243 }
244 break;
245 case 192 ... 255: {
246 const u16 idx = value - options;
247
248 if (ccid_hc_tx_parse_options(dp->dccps_hc_tx_ccid, sk,
249 opt, len, idx,
250 value) != 0)
251 goto out_invalid_option;
252 }
253 break;
254 default:
255 DCCP_CRIT("DCCP(%p): option %d(len=%d) not "
256 "implemented, ignoring", sk, opt, len);
257 break;
258 }
259 ignore_option:
260 if (opt != DCCPO_MANDATORY)
261 mandatory = 0;
262 }
263
264 /* mandatory was the last byte in option list -> reset connection */
265 if (mandatory)
266 goto out_invalid_option;
267
268 out_nonsensical_length:
269 /* RFC 4340, 5.8: ignore option and all remaining option space */
270 return 0;
271
272 out_invalid_option:
273 DCCP_INC_STATS_BH(DCCP_MIB_INVALIDOPT);
274 rc = DCCP_RESET_CODE_OPTION_ERROR;
275 out_featneg_failed:
276 DCCP_WARN("DCCP(%p): Option %d (len=%d) error=%u\n", sk, opt, len, rc);
277 DCCP_SKB_CB(skb)->dccpd_reset_code = rc;
278 DCCP_SKB_CB(skb)->dccpd_reset_data[0] = opt;
279 DCCP_SKB_CB(skb)->dccpd_reset_data[1] = len > 0 ? value[0] : 0;
280 DCCP_SKB_CB(skb)->dccpd_reset_data[2] = len > 1 ? value[1] : 0;
281 return -1;
282 }
283
284 EXPORT_SYMBOL_GPL(dccp_parse_options);
285
286 void dccp_encode_value_var(const u64 value, u8 *to, const u8 len)
287 {
288 if (len >= DCCP_OPTVAL_MAXLEN)
289 *to++ = (value & 0xFF0000000000ull) >> 40;
290 if (len > 4)
291 *to++ = (value & 0xFF00000000ull) >> 32;
292 if (len > 3)
293 *to++ = (value & 0xFF000000) >> 24;
294 if (len > 2)
295 *to++ = (value & 0xFF0000) >> 16;
296 if (len > 1)
297 *to++ = (value & 0xFF00) >> 8;
298 if (len > 0)
299 *to++ = (value & 0xFF);
300 }
301
302 static inline u8 dccp_ndp_len(const u64 ndp)
303 {
304 if (likely(ndp <= 0xFF))
305 return 1;
306 return likely(ndp <= USHORT_MAX) ? 2 : (ndp <= UINT_MAX ? 4 : 6);
307 }
308
309 int dccp_insert_option(struct sock *sk, struct sk_buff *skb,
310 const unsigned char option,
311 const void *value, const unsigned char len)
312 {
313 unsigned char *to;
314
315 if (DCCP_SKB_CB(skb)->dccpd_opt_len + len + 2 > DCCP_MAX_OPT_LEN)
316 return -1;
317
318 DCCP_SKB_CB(skb)->dccpd_opt_len += len + 2;
319
320 to = skb_push(skb, len + 2);
321 *to++ = option;
322 *to++ = len + 2;
323
324 memcpy(to, value, len);
325 return 0;
326 }
327
328 EXPORT_SYMBOL_GPL(dccp_insert_option);
329
330 static int dccp_insert_option_ndp(struct sock *sk, struct sk_buff *skb)
331 {
332 struct dccp_sock *dp = dccp_sk(sk);
333 u64 ndp = dp->dccps_ndp_count;
334
335 if (dccp_non_data_packet(skb))
336 ++dp->dccps_ndp_count;
337 else
338 dp->dccps_ndp_count = 0;
339
340 if (ndp > 0) {
341 unsigned char *ptr;
342 const int ndp_len = dccp_ndp_len(ndp);
343 const int len = ndp_len + 2;
344
345 if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN)
346 return -1;
347
348 DCCP_SKB_CB(skb)->dccpd_opt_len += len;
349
350 ptr = skb_push(skb, len);
351 *ptr++ = DCCPO_NDP_COUNT;
352 *ptr++ = len;
353 dccp_encode_value_var(ndp, ptr, ndp_len);
354 }
355
356 return 0;
357 }
358
359 static inline int dccp_elapsed_time_len(const u32 elapsed_time)
360 {
361 return elapsed_time == 0 ? 0 : elapsed_time <= 0xFFFF ? 2 : 4;
362 }
363
364 int dccp_insert_option_elapsed_time(struct sock *sk, struct sk_buff *skb,
365 u32 elapsed_time)
366 {
367 const int elapsed_time_len = dccp_elapsed_time_len(elapsed_time);
368 const int len = 2 + elapsed_time_len;
369 unsigned char *to;
370
371 if (elapsed_time_len == 0)
372 return 0;
373
374 if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN)
375 return -1;
376
377 DCCP_SKB_CB(skb)->dccpd_opt_len += len;
378
379 to = skb_push(skb, len);
380 *to++ = DCCPO_ELAPSED_TIME;
381 *to++ = len;
382
383 if (elapsed_time_len == 2) {
384 const __be16 var16 = htons((u16)elapsed_time);
385 memcpy(to, &var16, 2);
386 } else {
387 const __be32 var32 = htonl(elapsed_time);
388 memcpy(to, &var32, 4);
389 }
390
391 return 0;
392 }
393
394 EXPORT_SYMBOL_GPL(dccp_insert_option_elapsed_time);
395
396 int dccp_insert_option_timestamp(struct sock *sk, struct sk_buff *skb)
397 {
398 __be32 now = htonl(dccp_timestamp());
399 /* yes this will overflow but that is the point as we want a
400 * 10 usec 32 bit timer which mean it wraps every 11.9 hours */
401
402 return dccp_insert_option(sk, skb, DCCPO_TIMESTAMP, &now, sizeof(now));
403 }
404
405 EXPORT_SYMBOL_GPL(dccp_insert_option_timestamp);
406
407 static int dccp_insert_option_timestamp_echo(struct dccp_sock *dp,
408 struct dccp_request_sock *dreq,
409 struct sk_buff *skb)
410 {
411 __be32 tstamp_echo;
412 unsigned char *to;
413 u32 elapsed_time, elapsed_time_len, len;
414
415 if (dreq != NULL) {
416 elapsed_time = dccp_timestamp() - dreq->dreq_timestamp_time;
417 tstamp_echo = htonl(dreq->dreq_timestamp_echo);
418 dreq->dreq_timestamp_echo = 0;
419 } else {
420 elapsed_time = dccp_timestamp() - dp->dccps_timestamp_time;
421 tstamp_echo = htonl(dp->dccps_timestamp_echo);
422 dp->dccps_timestamp_echo = 0;
423 }
424
425 elapsed_time_len = dccp_elapsed_time_len(elapsed_time);
426 len = 6 + elapsed_time_len;
427
428 if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN)
429 return -1;
430
431 DCCP_SKB_CB(skb)->dccpd_opt_len += len;
432
433 to = skb_push(skb, len);
434 *to++ = DCCPO_TIMESTAMP_ECHO;
435 *to++ = len;
436
437 memcpy(to, &tstamp_echo, 4);
438 to += 4;
439
440 if (elapsed_time_len == 2) {
441 const __be16 var16 = htons((u16)elapsed_time);
442 memcpy(to, &var16, 2);
443 } else if (elapsed_time_len == 4) {
444 const __be32 var32 = htonl(elapsed_time);
445 memcpy(to, &var32, 4);
446 }
447
448 return 0;
449 }
450
451 /**
452 * dccp_insert_option_mandatory - Mandatory option (5.8.2)
453 * Note that since we are using skb_push, this function needs to be called
454 * _after_ inserting the option it is supposed to influence (stack order).
455 */
456 int dccp_insert_option_mandatory(struct sk_buff *skb)
457 {
458 if (DCCP_SKB_CB(skb)->dccpd_opt_len >= DCCP_MAX_OPT_LEN)
459 return -1;
460
461 DCCP_SKB_CB(skb)->dccpd_opt_len++;
462 *skb_push(skb, 1) = DCCPO_MANDATORY;
463 return 0;
464 }
465
466 /**
467 * dccp_insert_fn_opt - Insert single Feature-Negotiation option into @skb
468 * @type: %DCCPO_CHANGE_L, %DCCPO_CHANGE_R, %DCCPO_CONFIRM_L, %DCCPO_CONFIRM_R
469 * @feat: one out of %dccp_feature_numbers
470 * @val: NN value or SP array (preferred element first) to copy
471 * @len: true length of @val in bytes (excluding first element repetition)
472 * @repeat_first: whether to copy the first element of @val twice
473 * The last argument is used to construct Confirm options, where the preferred
474 * value and the preference list appear separately (RFC 4340, 6.3.1). Preference
475 * lists are kept such that the preferred entry is always first, so we only need
476 * to copy twice, and avoid the overhead of cloning into a bigger array.
477 */
478 int dccp_insert_fn_opt(struct sk_buff *skb, u8 type, u8 feat,
479 u8 *val, u8 len, bool repeat_first)
480 {
481 u8 tot_len, *to;
482
483 /* take the `Feature' field and possible repetition into account */
484 if (len > (DCCP_SINGLE_OPT_MAXLEN - 2)) {
485 DCCP_WARN("length %u for feature %u too large\n", len, feat);
486 return -1;
487 }
488
489 if (unlikely(val == NULL || len == 0))
490 len = repeat_first = 0;
491 tot_len = 3 + repeat_first + len;
492
493 if (DCCP_SKB_CB(skb)->dccpd_opt_len + tot_len > DCCP_MAX_OPT_LEN) {
494 DCCP_WARN("packet too small for feature %d option!\n", feat);
495 return -1;
496 }
497 DCCP_SKB_CB(skb)->dccpd_opt_len += tot_len;
498
499 to = skb_push(skb, tot_len);
500 *to++ = type;
501 *to++ = tot_len;
502 *to++ = feat;
503
504 if (repeat_first)
505 *to++ = *val;
506 if (len)
507 memcpy(to, val, len);
508
509 dccp_pr_debug("%s(%s (%d), ...), length %d\n",
510 dccp_feat_typename(type),
511 dccp_feat_name(feat), feat, len);
512 return 0;
513 }
514
515 /* The length of all options needs to be a multiple of 4 (5.8) */
516 static void dccp_insert_option_padding(struct sk_buff *skb)
517 {
518 int padding = DCCP_SKB_CB(skb)->dccpd_opt_len % 4;
519
520 if (padding != 0) {
521 padding = 4 - padding;
522 memset(skb_push(skb, padding), 0, padding);
523 DCCP_SKB_CB(skb)->dccpd_opt_len += padding;
524 }
525 }
526
527 int dccp_insert_options(struct sock *sk, struct sk_buff *skb)
528 {
529 struct dccp_sock *dp = dccp_sk(sk);
530 struct dccp_minisock *dmsk = dccp_msk(sk);
531
532 DCCP_SKB_CB(skb)->dccpd_opt_len = 0;
533
534 if (dmsk->dccpms_send_ndp_count &&
535 dccp_insert_option_ndp(sk, skb))
536 return -1;
537
538 if (DCCP_SKB_CB(skb)->dccpd_type != DCCP_PKT_DATA) {
539
540 /* Feature Negotiation */
541 if (dccp_feat_insert_opts(dp, NULL, skb))
542 return -1;
543
544 if (DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_REQUEST) {
545 /*
546 * Obtain RTT sample from Request/Response exchange.
547 * This is currently used in CCID 3 initialisation.
548 */
549 if (dccp_insert_option_timestamp(sk, skb))
550 return -1;
551
552 } else if (dmsk->dccpms_send_ack_vector &&
553 dccp_ackvec_pending(dp->dccps_hc_rx_ackvec) &&
554 dccp_insert_option_ackvec(sk, skb)) {
555 return -1;
556 }
557 }
558
559 if (dp->dccps_hc_rx_insert_options) {
560 if (ccid_hc_rx_insert_options(dp->dccps_hc_rx_ccid, sk, skb))
561 return -1;
562 dp->dccps_hc_rx_insert_options = 0;
563 }
564
565 if (dp->dccps_timestamp_echo != 0 &&
566 dccp_insert_option_timestamp_echo(dp, NULL, skb))
567 return -1;
568
569 dccp_insert_option_padding(skb);
570 return 0;
571 }
572
573 int dccp_insert_options_rsk(struct dccp_request_sock *dreq, struct sk_buff *skb)
574 {
575 DCCP_SKB_CB(skb)->dccpd_opt_len = 0;
576
577 if (dccp_feat_insert_opts(NULL, dreq, skb))
578 return -1;
579
580 if (dreq->dreq_timestamp_echo != 0 &&
581 dccp_insert_option_timestamp_echo(NULL, dreq, skb))
582 return -1;
583
584 dccp_insert_option_padding(skb);
585 return 0;
586 }
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