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>
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.
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>
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
;
32 u64
dccp_decode_value_var(const u8
*bf
, const u8 len
)
36 if (len
>= DCCP_OPTVAL_MAXLEN
)
37 value
+= ((u64
)*bf
++) << 40;
39 value
+= ((u64
)*bf
++) << 32;
41 value
+= ((u64
)*bf
++) << 24;
43 value
+= ((u64
)*bf
++) << 16;
45 value
+= ((u64
)*bf
++) << 8;
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
57 int dccp_parse_options(struct sock
*sk
, struct dccp_request_sock
*dreq
,
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
+
68 struct dccp_options_received
*opt_recv
= &dp
->dccps_options_received
;
69 unsigned char opt
, len
;
70 unsigned char *uninitialized_var(value
);
76 memset(opt_recv
, 0, sizeof(*opt_recv
));
79 while (opt_ptr
!= opt_end
) {
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
;
91 goto out_nonsensical_length
;
93 * Remove the type and len fields, leaving
100 if (opt_ptr
> opt_end
)
101 goto out_nonsensical_length
;
105 * CCID-Specific Options (from RFC 4340, sec. 10.3):
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.
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.
116 if (dreq
!= NULL
&& (opt
>= 128 ||
117 opt
== DCCPO_ACK_VECTOR_0
|| opt
== DCCPO_ACK_VECTOR_1
))
123 case DCCPO_MANDATORY
:
125 goto out_invalid_option
;
126 if (pkt_type
!= DCCP_PKT_DATA
)
129 case DCCPO_NDP_COUNT
:
131 goto out_invalid_option
;
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
);
137 case DCCPO_CHANGE_L
... DCCPO_CONFIRM_R
:
138 if (pkt_type
== DCCP_PKT_DATA
) /* RFC 4340, 6 */
140 rc
= dccp_feat_parse_options(sk
, dreq
, mandatory
, opt
,
141 *value
, value
+ 1, len
- 1);
143 goto out_featneg_failed
;
145 case DCCPO_ACK_VECTOR_0
:
146 case DCCPO_ACK_VECTOR_1
:
147 if (dccp_packet_without_ack(skb
)) /* RFC 4340, 11.4 */
150 if (dccp_msk(sk
)->dccpms_send_ack_vector
&&
151 dccp_ackvec_parse(sk
, skb
, &ackno
, opt
, value
, len
))
152 goto out_invalid_option
;
154 case DCCPO_TIMESTAMP
:
156 goto out_invalid_option
;
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.
162 opt_val
= get_unaligned((__be32
*)value
);
163 if (unlikely(opt_val
== 0)) {
164 DCCP_WARN("Timestamp with zero value\n");
169 dreq
->dreq_timestamp_echo
= ntohl(opt_val
);
170 dreq
->dreq_timestamp_time
= dccp_timestamp();
172 opt_recv
->dccpor_timestamp
=
173 dp
->dccps_timestamp_echo
= ntohl(opt_val
);
174 dp
->dccps_timestamp_time
= dccp_timestamp();
176 dccp_pr_debug("%s rx opt: TIMESTAMP=%u, ackno=%llu\n",
177 dccp_role(sk
), ntohl(opt_val
),
179 DCCP_SKB_CB(skb
)->dccpd_ack_seq
);
181 case DCCPO_TIMESTAMP_ECHO
:
182 if (len
!= 4 && len
!= 6 && len
!= 8)
183 goto out_invalid_option
;
185 opt_val
= get_unaligned((__be32
*)value
);
186 opt_recv
->dccpor_timestamp_echo
= ntohl(opt_val
);
188 dccp_pr_debug("%s rx opt: TIMESTAMP_ECHO=%u, len=%d, "
189 "ackno=%llu", dccp_role(sk
),
190 opt_recv
->dccpor_timestamp_echo
,
193 DCCP_SKB_CB(skb
)->dccpd_ack_seq
);
197 if (len
== 4) { /* no elapsed time included */
198 dccp_pr_debug_cat("\n");
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
);
210 dccp_pr_debug_cat(", ELAPSED_TIME=%u\n", elapsed_time
);
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
;
216 case DCCPO_ELAPSED_TIME
:
217 if (dccp_packet_without_ack(skb
)) /* RFC 4340, 13.2 */
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
);
227 goto out_invalid_option
;
230 if (elapsed_time
> opt_recv
->dccpor_elapsed_time
)
231 opt_recv
->dccpor_elapsed_time
= elapsed_time
;
233 dccp_pr_debug("%s rx opt: ELAPSED_TIME=%d\n",
234 dccp_role(sk
), elapsed_time
);
237 const u16 idx
= value
- options
;
239 if (ccid_hc_rx_parse_options(dp
->dccps_hc_rx_ccid
, sk
,
242 goto out_invalid_option
;
246 const u16 idx
= value
- options
;
248 if (ccid_hc_tx_parse_options(dp
->dccps_hc_tx_ccid
, sk
,
251 goto out_invalid_option
;
255 DCCP_CRIT("DCCP(%p): option %d(len=%d) not "
256 "implemented, ignoring", sk
, opt
, len
);
260 if (opt
!= DCCPO_MANDATORY
)
264 /* mandatory was the last byte in option list -> reset connection */
266 goto out_invalid_option
;
268 out_nonsensical_length
:
269 /* RFC 4340, 5.8: ignore option and all remaining option space */
273 DCCP_INC_STATS_BH(DCCP_MIB_INVALIDOPT
);
274 rc
= DCCP_RESET_CODE_OPTION_ERROR
;
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;
284 EXPORT_SYMBOL_GPL(dccp_parse_options
);
286 void dccp_encode_value_var(const u64 value
, u8
*to
, const u8 len
)
288 if (len
>= DCCP_OPTVAL_MAXLEN
)
289 *to
++ = (value
& 0xFF0000000000ull
) >> 40;
291 *to
++ = (value
& 0xFF00000000ull
) >> 32;
293 *to
++ = (value
& 0xFF000000) >> 24;
295 *to
++ = (value
& 0xFF0000) >> 16;
297 *to
++ = (value
& 0xFF00) >> 8;
299 *to
++ = (value
& 0xFF);
302 static inline u8
dccp_ndp_len(const u64 ndp
)
304 if (likely(ndp
<= 0xFF))
306 return likely(ndp
<= USHORT_MAX
) ? 2 : (ndp
<= UINT_MAX
? 4 : 6);
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
)
315 if (DCCP_SKB_CB(skb
)->dccpd_opt_len
+ len
+ 2 > DCCP_MAX_OPT_LEN
)
318 DCCP_SKB_CB(skb
)->dccpd_opt_len
+= len
+ 2;
320 to
= skb_push(skb
, len
+ 2);
324 memcpy(to
, value
, len
);
328 EXPORT_SYMBOL_GPL(dccp_insert_option
);
330 static int dccp_insert_option_ndp(struct sock
*sk
, struct sk_buff
*skb
)
332 struct dccp_sock
*dp
= dccp_sk(sk
);
333 u64 ndp
= dp
->dccps_ndp_count
;
335 if (dccp_non_data_packet(skb
))
336 ++dp
->dccps_ndp_count
;
338 dp
->dccps_ndp_count
= 0;
342 const int ndp_len
= dccp_ndp_len(ndp
);
343 const int len
= ndp_len
+ 2;
345 if (DCCP_SKB_CB(skb
)->dccpd_opt_len
+ len
> DCCP_MAX_OPT_LEN
)
348 DCCP_SKB_CB(skb
)->dccpd_opt_len
+= len
;
350 ptr
= skb_push(skb
, len
);
351 *ptr
++ = DCCPO_NDP_COUNT
;
353 dccp_encode_value_var(ndp
, ptr
, ndp_len
);
359 static inline int dccp_elapsed_time_len(const u32 elapsed_time
)
361 return elapsed_time
== 0 ? 0 : elapsed_time
<= 0xFFFF ? 2 : 4;
364 int dccp_insert_option_elapsed_time(struct sock
*sk
, struct sk_buff
*skb
,
367 const int elapsed_time_len
= dccp_elapsed_time_len(elapsed_time
);
368 const int len
= 2 + elapsed_time_len
;
371 if (elapsed_time_len
== 0)
374 if (DCCP_SKB_CB(skb
)->dccpd_opt_len
+ len
> DCCP_MAX_OPT_LEN
)
377 DCCP_SKB_CB(skb
)->dccpd_opt_len
+= len
;
379 to
= skb_push(skb
, len
);
380 *to
++ = DCCPO_ELAPSED_TIME
;
383 if (elapsed_time_len
== 2) {
384 const __be16 var16
= htons((u16
)elapsed_time
);
385 memcpy(to
, &var16
, 2);
387 const __be32 var32
= htonl(elapsed_time
);
388 memcpy(to
, &var32
, 4);
394 EXPORT_SYMBOL_GPL(dccp_insert_option_elapsed_time
);
396 int dccp_insert_option_timestamp(struct sock
*sk
, struct sk_buff
*skb
)
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 */
402 return dccp_insert_option(sk
, skb
, DCCPO_TIMESTAMP
, &now
, sizeof(now
));
405 EXPORT_SYMBOL_GPL(dccp_insert_option_timestamp
);
407 static int dccp_insert_option_timestamp_echo(struct dccp_sock
*dp
,
408 struct dccp_request_sock
*dreq
,
413 u32 elapsed_time
, elapsed_time_len
, len
;
416 elapsed_time
= dccp_timestamp() - dreq
->dreq_timestamp_time
;
417 tstamp_echo
= htonl(dreq
->dreq_timestamp_echo
);
418 dreq
->dreq_timestamp_echo
= 0;
420 elapsed_time
= dccp_timestamp() - dp
->dccps_timestamp_time
;
421 tstamp_echo
= htonl(dp
->dccps_timestamp_echo
);
422 dp
->dccps_timestamp_echo
= 0;
425 elapsed_time_len
= dccp_elapsed_time_len(elapsed_time
);
426 len
= 6 + elapsed_time_len
;
428 if (DCCP_SKB_CB(skb
)->dccpd_opt_len
+ len
> DCCP_MAX_OPT_LEN
)
431 DCCP_SKB_CB(skb
)->dccpd_opt_len
+= len
;
433 to
= skb_push(skb
, len
);
434 *to
++ = DCCPO_TIMESTAMP_ECHO
;
437 memcpy(to
, &tstamp_echo
, 4);
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);
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).
456 int dccp_insert_option_mandatory(struct sk_buff
*skb
)
458 if (DCCP_SKB_CB(skb
)->dccpd_opt_len
>= DCCP_MAX_OPT_LEN
)
461 DCCP_SKB_CB(skb
)->dccpd_opt_len
++;
462 *skb_push(skb
, 1) = DCCPO_MANDATORY
;
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.
478 int dccp_insert_fn_opt(struct sk_buff
*skb
, u8 type
, u8 feat
,
479 u8
*val
, u8 len
, bool repeat_first
)
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
);
489 if (unlikely(val
== NULL
|| len
== 0))
490 len
= repeat_first
= 0;
491 tot_len
= 3 + repeat_first
+ len
;
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
);
497 DCCP_SKB_CB(skb
)->dccpd_opt_len
+= tot_len
;
499 to
= skb_push(skb
, tot_len
);
507 memcpy(to
, val
, len
);
509 dccp_pr_debug("%s(%s (%d), ...), length %d\n",
510 dccp_feat_typename(type
),
511 dccp_feat_name(feat
), feat
, len
);
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
)
518 int padding
= DCCP_SKB_CB(skb
)->dccpd_opt_len
% 4;
521 padding
= 4 - padding
;
522 memset(skb_push(skb
, padding
), 0, padding
);
523 DCCP_SKB_CB(skb
)->dccpd_opt_len
+= padding
;
527 int dccp_insert_options(struct sock
*sk
, struct sk_buff
*skb
)
529 struct dccp_sock
*dp
= dccp_sk(sk
);
530 struct dccp_minisock
*dmsk
= dccp_msk(sk
);
532 DCCP_SKB_CB(skb
)->dccpd_opt_len
= 0;
534 if (dmsk
->dccpms_send_ndp_count
&&
535 dccp_insert_option_ndp(sk
, skb
))
538 if (DCCP_SKB_CB(skb
)->dccpd_type
!= DCCP_PKT_DATA
) {
540 /* Feature Negotiation */
541 if (dccp_feat_insert_opts(dp
, NULL
, skb
))
544 if (DCCP_SKB_CB(skb
)->dccpd_type
== DCCP_PKT_REQUEST
) {
546 * Obtain RTT sample from Request/Response exchange.
547 * This is currently used in CCID 3 initialisation.
549 if (dccp_insert_option_timestamp(sk
, skb
))
552 } else if (dmsk
->dccpms_send_ack_vector
&&
553 dccp_ackvec_pending(dp
->dccps_hc_rx_ackvec
) &&
554 dccp_insert_option_ackvec(sk
, skb
)) {
559 if (dp
->dccps_hc_rx_insert_options
) {
560 if (ccid_hc_rx_insert_options(dp
->dccps_hc_rx_ccid
, sk
, skb
))
562 dp
->dccps_hc_rx_insert_options
= 0;
565 if (dp
->dccps_timestamp_echo
!= 0 &&
566 dccp_insert_option_timestamp_echo(dp
, NULL
, skb
))
569 dccp_insert_option_padding(skb
);
573 int dccp_insert_options_rsk(struct dccp_request_sock
*dreq
, struct sk_buff
*skb
)
575 DCCP_SKB_CB(skb
)->dccpd_opt_len
= 0;
577 if (dccp_feat_insert_opts(NULL
, dreq
, skb
))
580 if (dreq
->dreq_timestamp_echo
!= 0 &&
581 dccp_insert_option_timestamp_echo(NULL
, dreq
, skb
))
584 dccp_insert_option_padding(skb
);