4 * An implementation of the DCCP protocol
5 * Andrea Bittau <a.bittau@cs.ucl.ac.uk>
9 * o Feature negotiation is coordinated with connection setup (as in TCP), wild
10 * changes of parameters of an established connection are not supported.
11 * o All currently known SP features have 1-byte quantities. If in the future
12 * extensions of RFCs 4340..42 define features with item lengths larger than
13 * one byte, a feature-specific extension of the code will be required.
15 * This program is free software; you can redistribute it and/or
16 * modify it under the terms of the GNU General Public License
17 * as published by the Free Software Foundation; either version
18 * 2 of the License, or (at your option) any later version.
21 #include <linux/module.h>
26 #define DCCP_FEAT_SP_NOAGREE (-123)
29 u8 feat_num
; /* DCCPF_xxx */
30 enum dccp_feat_type rxtx
; /* RX or TX */
31 enum dccp_feat_type reconciliation
; /* SP or NN */
32 u8 default_value
; /* as in 6.4 */
34 * Lookup table for location and type of features (from RFC 4340/4342)
35 * +--------------------------+----+-----+----+----+---------+-----------+
36 * | Feature | Location | Reconc. | Initial | Section |
37 * | | RX | TX | SP | NN | Value | Reference |
38 * +--------------------------+----+-----+----+----+---------+-----------+
39 * | DCCPF_CCID | | X | X | | 2 | 10 |
40 * | DCCPF_SHORT_SEQNOS | | X | X | | 0 | 7.6.1 |
41 * | DCCPF_SEQUENCE_WINDOW | | X | | X | 100 | 7.5.2 |
42 * | DCCPF_ECN_INCAPABLE | X | | X | | 0 | 12.1 |
43 * | DCCPF_ACK_RATIO | | X | | X | 2 | 11.3 |
44 * | DCCPF_SEND_ACK_VECTOR | X | | X | | 0 | 11.5 |
45 * | DCCPF_SEND_NDP_COUNT | | X | X | | 0 | 7.7.2 |
46 * | DCCPF_MIN_CSUM_COVER | X | | X | | 0 | 9.2.1 |
47 * | DCCPF_DATA_CHECKSUM | X | | X | | 0 | 9.3.1 |
48 * | DCCPF_SEND_LEV_RATE | X | | X | | 0 | 4342/8.4 |
49 * +--------------------------+----+-----+----+----+---------+-----------+
51 } dccp_feat_table
[] = {
52 { DCCPF_CCID
, FEAT_AT_TX
, FEAT_SP
, 2 },
53 { DCCPF_SHORT_SEQNOS
, FEAT_AT_TX
, FEAT_SP
, 0 },
54 { DCCPF_SEQUENCE_WINDOW
, FEAT_AT_TX
, FEAT_NN
, 100 },
55 { DCCPF_ECN_INCAPABLE
, FEAT_AT_RX
, FEAT_SP
, 0 },
56 { DCCPF_ACK_RATIO
, FEAT_AT_TX
, FEAT_NN
, 2 },
57 { DCCPF_SEND_ACK_VECTOR
, FEAT_AT_RX
, FEAT_SP
, 0 },
58 { DCCPF_SEND_NDP_COUNT
, FEAT_AT_TX
, FEAT_SP
, 0 },
59 { DCCPF_MIN_CSUM_COVER
, FEAT_AT_RX
, FEAT_SP
, 0 },
60 { DCCPF_DATA_CHECKSUM
, FEAT_AT_RX
, FEAT_SP
, 0 },
61 { DCCPF_SEND_LEV_RATE
, FEAT_AT_RX
, FEAT_SP
, 0 },
63 #define DCCP_FEAT_SUPPORTED_MAX ARRAY_SIZE(dccp_feat_table)
66 * dccp_feat_index - Hash function to map feature number into array position
67 * Returns consecutive array index or -1 if the feature is not understood.
69 static int dccp_feat_index(u8 feat_num
)
71 /* The first 9 entries are occupied by the types from RFC 4340, 6.4 */
72 if (feat_num
> DCCPF_RESERVED
&& feat_num
<= DCCPF_DATA_CHECKSUM
)
76 * Other features: add cases for new feature types here after adding
77 * them to the above table.
80 case DCCPF_SEND_LEV_RATE
:
81 return DCCP_FEAT_SUPPORTED_MAX
- 1;
86 static u8
dccp_feat_type(u8 feat_num
)
88 int idx
= dccp_feat_index(feat_num
);
92 return dccp_feat_table
[idx
].reconciliation
;
95 static int dccp_feat_default_value(u8 feat_num
)
97 int idx
= dccp_feat_index(feat_num
);
99 * There are no default values for unknown features, so encountering a
100 * negative index here indicates a serious problem somewhere else.
102 DCCP_BUG_ON(idx
< 0);
104 return idx
< 0 ? 0 : dccp_feat_table
[idx
].default_value
;
107 /* copy constructor, fval must not already contain allocated memory */
108 static int dccp_feat_clone_sp_val(dccp_feat_val
*fval
, u8
const *val
, u8 len
)
111 if (fval
->sp
.len
> 0) {
112 fval
->sp
.vec
= kmemdup(val
, len
, gfp_any());
113 if (fval
->sp
.vec
== NULL
) {
121 static void dccp_feat_val_destructor(u8 feat_num
, dccp_feat_val
*val
)
123 if (unlikely(val
== NULL
))
125 if (dccp_feat_type(feat_num
) == FEAT_SP
)
127 memset(val
, 0, sizeof(*val
));
130 static struct dccp_feat_entry
*
131 dccp_feat_clone_entry(struct dccp_feat_entry
const *original
)
133 struct dccp_feat_entry
*new;
134 u8 type
= dccp_feat_type(original
->feat_num
);
136 if (type
== FEAT_UNKNOWN
)
139 new = kmemdup(original
, sizeof(struct dccp_feat_entry
), gfp_any());
143 if (type
== FEAT_SP
&& dccp_feat_clone_sp_val(&new->val
,
144 original
->val
.sp
.vec
,
145 original
->val
.sp
.len
)) {
152 static void dccp_feat_entry_destructor(struct dccp_feat_entry
*entry
)
155 dccp_feat_val_destructor(entry
->feat_num
, &entry
->val
);
161 * List management functions
163 * Feature negotiation lists rely on and maintain the following invariants:
164 * - each feat_num in the list is known, i.e. we know its type and default value
165 * - each feat_num/is_local combination is unique (old entries are overwritten)
166 * - SP values are always freshly allocated
167 * - list is sorted in increasing order of feature number (faster lookup)
169 static struct dccp_feat_entry
*dccp_feat_list_lookup(struct list_head
*fn_list
,
170 u8 feat_num
, bool is_local
)
172 struct dccp_feat_entry
*entry
;
174 list_for_each_entry(entry
, fn_list
, node
) {
175 if (entry
->feat_num
== feat_num
&& entry
->is_local
== is_local
)
177 else if (entry
->feat_num
> feat_num
)
184 * dccp_feat_entry_new - Central list update routine (called by all others)
185 * @head: list to add to
186 * @feat: feature number
187 * @local: whether the local (1) or remote feature with number @feat is meant
188 * This is the only constructor and serves to ensure the above invariants.
190 static struct dccp_feat_entry
*
191 dccp_feat_entry_new(struct list_head
*head
, u8 feat
, bool local
)
193 struct dccp_feat_entry
*entry
;
195 list_for_each_entry(entry
, head
, node
)
196 if (entry
->feat_num
== feat
&& entry
->is_local
== local
) {
197 dccp_feat_val_destructor(entry
->feat_num
, &entry
->val
);
199 } else if (entry
->feat_num
> feat
) {
204 entry
= kmalloc(sizeof(*entry
), gfp_any());
206 entry
->feat_num
= feat
;
207 entry
->is_local
= local
;
208 list_add_tail(&entry
->node
, head
);
214 * dccp_feat_push_change - Add/overwrite a Change option in the list
215 * @fn_list: feature-negotiation list to update
216 * @feat: one of %dccp_feature_numbers
217 * @local: whether local (1) or remote (0) @feat_num is meant
218 * @needs_mandatory: whether to use Mandatory feature negotiation options
219 * @fval: pointer to NN/SP value to be inserted (will be copied)
221 static int dccp_feat_push_change(struct list_head
*fn_list
, u8 feat
, u8 local
,
222 u8 mandatory
, dccp_feat_val
*fval
)
224 struct dccp_feat_entry
*new = dccp_feat_entry_new(fn_list
, feat
, local
);
229 new->feat_num
= feat
;
230 new->is_local
= local
;
231 new->state
= FEAT_INITIALISING
;
232 new->needs_confirm
= 0;
233 new->empty_confirm
= 0;
235 new->needs_mandatory
= mandatory
;
240 static inline void dccp_feat_list_pop(struct dccp_feat_entry
*entry
)
242 list_del(&entry
->node
);
243 dccp_feat_entry_destructor(entry
);
246 void dccp_feat_list_purge(struct list_head
*fn_list
)
248 struct dccp_feat_entry
*entry
, *next
;
250 list_for_each_entry_safe(entry
, next
, fn_list
, node
)
251 dccp_feat_entry_destructor(entry
);
252 INIT_LIST_HEAD(fn_list
);
254 EXPORT_SYMBOL_GPL(dccp_feat_list_purge
);
256 /* generate @to as full clone of @from - @to must not contain any nodes */
257 int dccp_feat_clone_list(struct list_head
const *from
, struct list_head
*to
)
259 struct dccp_feat_entry
*entry
, *new;
262 list_for_each_entry(entry
, from
, node
) {
263 new = dccp_feat_clone_entry(entry
);
266 list_add_tail(&new->node
, to
);
271 dccp_feat_list_purge(to
);
275 static u8
dccp_feat_is_valid_nn_val(u8 feat_num
, u64 val
)
278 case DCCPF_ACK_RATIO
:
279 return val
<= DCCPF_ACK_RATIO_MAX
;
280 case DCCPF_SEQUENCE_WINDOW
:
281 return val
>= DCCPF_SEQ_WMIN
&& val
<= DCCPF_SEQ_WMAX
;
283 return 0; /* feature unknown - so we can't tell */
286 /* check that SP values are within the ranges defined in RFC 4340 */
287 static u8
dccp_feat_is_valid_sp_val(u8 feat_num
, u8 val
)
291 return val
== DCCPC_CCID2
|| val
== DCCPC_CCID3
;
292 /* Type-check Boolean feature values: */
293 case DCCPF_SHORT_SEQNOS
:
294 case DCCPF_ECN_INCAPABLE
:
295 case DCCPF_SEND_ACK_VECTOR
:
296 case DCCPF_SEND_NDP_COUNT
:
297 case DCCPF_DATA_CHECKSUM
:
298 case DCCPF_SEND_LEV_RATE
:
300 case DCCPF_MIN_CSUM_COVER
:
303 return 0; /* feature unknown */
306 static u8
dccp_feat_sp_list_ok(u8 feat_num
, u8
const *sp_list
, u8 sp_len
)
308 if (sp_list
== NULL
|| sp_len
< 1)
311 if (!dccp_feat_is_valid_sp_val(feat_num
, *sp_list
++))
317 * __feat_register_nn - Register new NN value on socket
318 * @fn: feature-negotiation list to register with
319 * @feat: an NN feature from %dccp_feature_numbers
320 * @mandatory: use Mandatory option if 1
321 * @nn_val: value to register (restricted to 4 bytes)
322 * Note that NN features are local by definition (RFC 4340, 6.3.2).
324 static int __feat_register_nn(struct list_head
*fn
, u8 feat
,
325 u8 mandatory
, u64 nn_val
)
327 dccp_feat_val fval
= { .nn
= nn_val
};
329 if (dccp_feat_type(feat
) != FEAT_NN
||
330 !dccp_feat_is_valid_nn_val(feat
, nn_val
))
333 /* Don't bother with default values, they will be activated anyway. */
334 if (nn_val
- (u64
)dccp_feat_default_value(feat
) == 0)
337 return dccp_feat_push_change(fn
, feat
, 1, mandatory
, &fval
);
341 * __feat_register_sp - Register new SP value/list on socket
342 * @fn: feature-negotiation list to register with
343 * @feat: an SP feature from %dccp_feature_numbers
344 * @is_local: whether the local (1) or the remote (0) @feat is meant
345 * @mandatory: use Mandatory option if 1
346 * @sp_val: SP value followed by optional preference list
347 * @sp_len: length of @sp_val in bytes
349 static int __feat_register_sp(struct list_head
*fn
, u8 feat
, u8 is_local
,
350 u8 mandatory
, u8
const *sp_val
, u8 sp_len
)
354 if (dccp_feat_type(feat
) != FEAT_SP
||
355 !dccp_feat_sp_list_ok(feat
, sp_val
, sp_len
))
358 /* Avoid negotiating alien CCIDs by only advertising supported ones */
359 if (feat
== DCCPF_CCID
&& !ccid_support_check(sp_val
, sp_len
))
362 if (dccp_feat_clone_sp_val(&fval
, sp_val
, sp_len
))
365 return dccp_feat_push_change(fn
, feat
, is_local
, mandatory
, &fval
);
369 * dccp_feat_register_sp - Register requests to change SP feature values
370 * @sk: client or listening socket
371 * @feat: one of %dccp_feature_numbers
372 * @is_local: whether the local (1) or remote (0) @feat is meant
373 * @list: array of preferred values, in descending order of preference
374 * @len: length of @list in bytes
376 int dccp_feat_register_sp(struct sock
*sk
, u8 feat
, u8 is_local
,
377 u8
const *list
, u8 len
)
378 { /* any changes must be registered before establishing the connection */
379 if (sk
->sk_state
!= DCCP_CLOSED
)
381 if (dccp_feat_type(feat
) != FEAT_SP
)
383 return __feat_register_sp(&dccp_sk(sk
)->dccps_featneg
, feat
, is_local
,
387 /* Analogous to dccp_feat_register_sp(), but for non-negotiable values */
388 int dccp_feat_register_nn(struct sock
*sk
, u8 feat
, u64 val
)
390 /* any changes must be registered before establishing the connection */
391 if (sk
->sk_state
!= DCCP_CLOSED
)
393 if (dccp_feat_type(feat
) != FEAT_NN
)
395 return __feat_register_nn(&dccp_sk(sk
)->dccps_featneg
, feat
, 0, val
);
399 * Tracking features whose value depend on the choice of CCID
401 * This is designed with an extension in mind so that a list walk could be done
402 * before activating any features. However, the existing framework was found to
403 * work satisfactorily up until now, the automatic verification is left open.
404 * When adding new CCIDs, add a corresponding dependency table here.
406 static const struct ccid_dependency
*dccp_feat_ccid_deps(u8 ccid
, bool is_local
)
408 static const struct ccid_dependency ccid2_dependencies
[2][2] = {
410 * CCID2 mandates Ack Vectors (RFC 4341, 4.): as CCID is a TX
411 * feature and Send Ack Vector is an RX feature, `is_local'
412 * needs to be reversed.
414 { /* Dependencies of the receiver-side (remote) CCID2 */
416 .dependent_feat
= DCCPF_SEND_ACK_VECTOR
,
418 .is_mandatory
= true,
423 { /* Dependencies of the sender-side (local) CCID2 */
425 .dependent_feat
= DCCPF_SEND_ACK_VECTOR
,
427 .is_mandatory
= true,
433 static const struct ccid_dependency ccid3_dependencies
[2][5] = {
435 * Dependencies of the receiver-side CCID3
437 { /* locally disable Ack Vectors */
438 .dependent_feat
= DCCPF_SEND_ACK_VECTOR
,
440 .is_mandatory
= false,
443 { /* see below why Send Loss Event Rate is on */
444 .dependent_feat
= DCCPF_SEND_LEV_RATE
,
446 .is_mandatory
= true,
449 { /* NDP Count is needed as per RFC 4342, 6.1.1 */
450 .dependent_feat
= DCCPF_SEND_NDP_COUNT
,
452 .is_mandatory
= true,
458 * CCID3 at the TX side: we request that the HC-receiver
459 * will not send Ack Vectors (they will be ignored, so
460 * Mandatory is not set); we enable Send Loss Event Rate
461 * (Mandatory since the implementation does not support
462 * the Loss Intervals option of RFC 4342, 8.6).
463 * The last two options are for peer's information only.
466 .dependent_feat
= DCCPF_SEND_ACK_VECTOR
,
468 .is_mandatory
= false,
472 .dependent_feat
= DCCPF_SEND_LEV_RATE
,
474 .is_mandatory
= true,
477 { /* this CCID does not support Ack Ratio */
478 .dependent_feat
= DCCPF_ACK_RATIO
,
480 .is_mandatory
= false,
483 { /* tell receiver we are sending NDP counts */
484 .dependent_feat
= DCCPF_SEND_NDP_COUNT
,
486 .is_mandatory
= false,
494 return ccid2_dependencies
[is_local
];
496 return ccid3_dependencies
[is_local
];
503 * dccp_feat_propagate_ccid - Resolve dependencies of features on choice of CCID
504 * @fn: feature-negotiation list to update
505 * @id: CCID number to track
506 * @is_local: whether TX CCID (1) or RX CCID (0) is meant
507 * This function needs to be called after registering all other features.
509 static int dccp_feat_propagate_ccid(struct list_head
*fn
, u8 id
, bool is_local
)
511 const struct ccid_dependency
*table
= dccp_feat_ccid_deps(id
, is_local
);
512 int i
, rc
= (table
== NULL
);
514 for (i
= 0; rc
== 0 && table
[i
].dependent_feat
!= DCCPF_RESERVED
; i
++)
515 if (dccp_feat_type(table
[i
].dependent_feat
) == FEAT_SP
)
516 rc
= __feat_register_sp(fn
, table
[i
].dependent_feat
,
518 table
[i
].is_mandatory
,
521 rc
= __feat_register_nn(fn
, table
[i
].dependent_feat
,
522 table
[i
].is_mandatory
,
528 * dccp_feat_finalise_settings - Finalise settings before starting negotiation
529 * @dp: client or listening socket (settings will be inherited)
530 * This is called after all registrations (socket initialisation, sysctls, and
531 * sockopt calls), and before sending the first packet containing Change options
532 * (ie. client-Request or server-Response), to ensure internal consistency.
534 int dccp_feat_finalise_settings(struct dccp_sock
*dp
)
536 struct list_head
*fn
= &dp
->dccps_featneg
;
537 struct dccp_feat_entry
*entry
;
538 int i
= 2, ccids
[2] = { -1, -1 };
542 * 1) not useful to propagate CCID settings if this host advertises more
543 * than one CCID: the choice of CCID may still change - if this is
544 * the client, or if this is the server and the client sends
545 * singleton CCID values.
546 * 2) since is that propagate_ccid changes the list, we defer changing
547 * the sorted list until after the traversal.
549 list_for_each_entry(entry
, fn
, node
)
550 if (entry
->feat_num
== DCCPF_CCID
&& entry
->val
.sp
.len
== 1)
551 ccids
[entry
->is_local
] = entry
->val
.sp
.vec
[0];
553 if (ccids
[i
] > 0 && dccp_feat_propagate_ccid(fn
, ccids
[i
], i
))
559 * dccp_feat_server_ccid_dependencies - Resolve CCID-dependent features
560 * It is the server which resolves the dependencies once the CCID has been
561 * fully negotiated. If no CCID has been negotiated, it uses the default CCID.
563 int dccp_feat_server_ccid_dependencies(struct dccp_request_sock
*dreq
)
565 struct list_head
*fn
= &dreq
->dreq_featneg
;
566 struct dccp_feat_entry
*entry
;
569 for (is_local
= 0; is_local
<= 1; is_local
++) {
570 entry
= dccp_feat_list_lookup(fn
, DCCPF_CCID
, is_local
);
572 if (entry
!= NULL
&& !entry
->empty_confirm
)
573 ccid
= entry
->val
.sp
.vec
[0];
575 ccid
= dccp_feat_default_value(DCCPF_CCID
);
577 if (dccp_feat_propagate_ccid(fn
, ccid
, is_local
))
583 static int dccp_feat_update_ccid(struct sock
*sk
, u8 type
, u8 new_ccid_nr
)
585 struct dccp_sock
*dp
= dccp_sk(sk
);
586 struct dccp_minisock
*dmsk
= dccp_msk(sk
);
587 /* figure out if we are changing our CCID or the peer's */
588 const int rx
= type
== DCCPO_CHANGE_R
;
589 const u8 ccid_nr
= rx
? dmsk
->dccpms_rx_ccid
: dmsk
->dccpms_tx_ccid
;
590 struct ccid
*new_ccid
;
592 /* Check if nothing is being changed. */
593 if (ccid_nr
== new_ccid_nr
)
596 new_ccid
= ccid_new(new_ccid_nr
, sk
, rx
, GFP_ATOMIC
);
597 if (new_ccid
== NULL
)
601 ccid_hc_rx_delete(dp
->dccps_hc_rx_ccid
, sk
);
602 dp
->dccps_hc_rx_ccid
= new_ccid
;
603 dmsk
->dccpms_rx_ccid
= new_ccid_nr
;
605 ccid_hc_tx_delete(dp
->dccps_hc_tx_ccid
, sk
);
606 dp
->dccps_hc_tx_ccid
= new_ccid
;
607 dmsk
->dccpms_tx_ccid
= new_ccid_nr
;
613 static int dccp_feat_update(struct sock
*sk
, u8 type
, u8 feat
, u8 val
)
615 dccp_feat_debug(type
, feat
, val
);
619 return dccp_feat_update_ccid(sk
, type
, val
);
621 dccp_pr_debug("UNIMPLEMENTED: %s(%d, ...)\n",
622 dccp_feat_typename(type
), feat
);
628 static int dccp_feat_reconcile(struct sock
*sk
, struct dccp_opt_pend
*opt
,
631 struct dccp_sock
*dp
= dccp_sk(sk
);
632 u8
*spref
, slen
, *res
= NULL
;
633 int i
, j
, rc
, agree
= 1;
635 BUG_ON(rpref
== NULL
);
637 /* check if we are the black sheep */
638 if (dp
->dccps_role
== DCCP_ROLE_CLIENT
) {
641 rpref
= opt
->dccpop_val
;
642 rlen
= opt
->dccpop_len
;
644 spref
= opt
->dccpop_val
;
645 slen
= opt
->dccpop_len
;
648 * Now we have server preference list in spref and client preference in
651 BUG_ON(spref
== NULL
);
652 BUG_ON(rpref
== NULL
);
654 /* FIXME sanity check vals */
656 /* Are values in any order? XXX Lame "algorithm" here */
657 for (i
= 0; i
< slen
; i
++) {
658 for (j
= 0; j
< rlen
; j
++) {
659 if (spref
[i
] == rpref
[j
]) {
668 /* we didn't agree on anything */
670 /* confirm previous value */
671 switch (opt
->dccpop_feat
) {
673 /* XXX did i get this right? =P */
674 if (opt
->dccpop_type
== DCCPO_CHANGE_L
)
675 res
= &dccp_msk(sk
)->dccpms_tx_ccid
;
677 res
= &dccp_msk(sk
)->dccpms_rx_ccid
;
681 DCCP_BUG("Fell through, feat=%d", opt
->dccpop_feat
);
682 /* XXX implement res */
686 dccp_pr_debug("Don't agree... reconfirming %d\n", *res
);
687 agree
= 0; /* this is used for mandatory options... */
690 /* need to put result and our preference list */
691 rlen
= 1 + opt
->dccpop_len
;
692 rpref
= kmalloc(rlen
, GFP_ATOMIC
);
697 memcpy(&rpref
[1], opt
->dccpop_val
, opt
->dccpop_len
);
699 /* put it in the "confirm queue" */
700 if (opt
->dccpop_sc
== NULL
) {
701 opt
->dccpop_sc
= kmalloc(sizeof(*opt
->dccpop_sc
), GFP_ATOMIC
);
702 if (opt
->dccpop_sc
== NULL
) {
707 /* recycle the confirm slot */
708 BUG_ON(opt
->dccpop_sc
->dccpoc_val
== NULL
);
709 kfree(opt
->dccpop_sc
->dccpoc_val
);
710 dccp_pr_debug("recycling confirm slot\n");
712 memset(opt
->dccpop_sc
, 0, sizeof(*opt
->dccpop_sc
));
714 opt
->dccpop_sc
->dccpoc_val
= rpref
;
715 opt
->dccpop_sc
->dccpoc_len
= rlen
;
717 /* update the option on our side [we are about to send the confirm] */
718 rc
= dccp_feat_update(sk
, opt
->dccpop_type
, opt
->dccpop_feat
, *res
);
720 kfree(opt
->dccpop_sc
->dccpoc_val
);
721 kfree(opt
->dccpop_sc
);
722 opt
->dccpop_sc
= NULL
;
726 dccp_pr_debug("Will confirm %d\n", *rpref
);
728 /* say we want to change to X but we just got a confirm X, suppress our
731 if (!opt
->dccpop_conf
) {
732 if (*opt
->dccpop_val
== *res
)
733 opt
->dccpop_conf
= 1;
734 dccp_pr_debug("won't ask for change of same feature\n");
737 return agree
? 0 : DCCP_FEAT_SP_NOAGREE
; /* used for mandatory opts */
740 static int dccp_feat_sp(struct sock
*sk
, u8 type
, u8 feature
, u8
*val
, u8 len
)
742 struct dccp_minisock
*dmsk
= dccp_msk(sk
);
743 struct dccp_opt_pend
*opt
;
748 * We received a CHANGE. We gotta match it against our own preference
749 * list. If we got a CHANGE_R it means it's a change for us, so we need
750 * to compare our CHANGE_L list.
752 if (type
== DCCPO_CHANGE_L
)
757 /* find our preference list for this feature */
758 list_for_each_entry(opt
, &dmsk
->dccpms_pending
, dccpop_node
) {
759 if (opt
->dccpop_type
!= t
|| opt
->dccpop_feat
!= feature
)
762 /* find the winner from the two preference lists */
763 rc
= dccp_feat_reconcile(sk
, opt
, val
, len
);
767 /* We didn't deal with the change. This can happen if we have no
768 * preference list for the feature. In fact, it just shouldn't
769 * happen---if we understand a feature, we should have a preference list
770 * with at least the default value.
777 static int dccp_feat_nn(struct sock
*sk
, u8 type
, u8 feature
, u8
*val
, u8 len
)
779 struct dccp_opt_pend
*opt
;
780 struct dccp_minisock
*dmsk
= dccp_msk(sk
);
784 /* NN features must be Change L (sec. 6.3.2) */
785 if (type
!= DCCPO_CHANGE_L
) {
786 dccp_pr_debug("received %s for NN feature %d\n",
787 dccp_feat_typename(type
), feature
);
791 /* XXX sanity check opt val */
793 /* copy option so we can confirm it */
794 opt
= kzalloc(sizeof(*opt
), GFP_ATOMIC
);
798 copy
= kmemdup(val
, len
, GFP_ATOMIC
);
804 opt
->dccpop_type
= DCCPO_CONFIRM_R
; /* NN can only confirm R */
805 opt
->dccpop_feat
= feature
;
806 opt
->dccpop_val
= copy
;
807 opt
->dccpop_len
= len
;
810 rc
= dccp_feat_update(sk
, type
, feature
, *val
);
812 kfree(opt
->dccpop_val
);
817 dccp_feat_debug(type
, feature
, *copy
);
819 list_add_tail(&opt
->dccpop_node
, &dmsk
->dccpms_conf
);
824 static void dccp_feat_empty_confirm(struct dccp_minisock
*dmsk
,
827 /* XXX check if other confirms for that are queued and recycle slot */
828 struct dccp_opt_pend
*opt
= kzalloc(sizeof(*opt
), GFP_ATOMIC
);
831 /* XXX what do we do? Ignoring should be fine. It's a change
839 opt
->dccpop_type
= DCCPO_CONFIRM_R
;
842 opt
->dccpop_type
= DCCPO_CONFIRM_L
;
845 DCCP_WARN("invalid type %d\n", type
);
849 opt
->dccpop_feat
= feature
;
850 opt
->dccpop_val
= NULL
;
854 dccp_pr_debug("Empty %s(%d)\n", dccp_feat_typename(type
), feature
);
856 list_add_tail(&opt
->dccpop_node
, &dmsk
->dccpms_conf
);
859 static void dccp_feat_flush_confirm(struct sock
*sk
)
861 struct dccp_minisock
*dmsk
= dccp_msk(sk
);
862 /* Check if there is anything to confirm in the first place */
863 int yes
= !list_empty(&dmsk
->dccpms_conf
);
866 struct dccp_opt_pend
*opt
;
868 list_for_each_entry(opt
, &dmsk
->dccpms_pending
, dccpop_node
) {
869 if (opt
->dccpop_conf
) {
879 /* OK there is something to confirm... */
880 /* XXX check if packet is in flight? Send delayed ack?? */
881 if (sk
->sk_state
== DCCP_OPEN
)
885 int dccp_feat_change_recv(struct sock
*sk
, u8 type
, u8 feature
, u8
*val
, u8 len
)
889 /* Ignore Change requests other than during connection setup */
890 if (sk
->sk_state
!= DCCP_LISTEN
&& sk
->sk_state
!= DCCP_REQUESTING
)
892 dccp_feat_debug(type
, feature
, *val
);
894 /* figure out if it's SP or NN feature */
896 /* deal with SP features */
898 rc
= dccp_feat_sp(sk
, type
, feature
, val
, len
);
901 /* deal with NN features */
902 case DCCPF_ACK_RATIO
:
903 rc
= dccp_feat_nn(sk
, type
, feature
, val
, len
);
906 /* XXX implement other features */
908 dccp_pr_debug("UNIMPLEMENTED: not handling %s(%d, ...)\n",
909 dccp_feat_typename(type
), feature
);
914 /* check if there were problems changing features */
916 /* If we don't agree on SP, we sent a confirm for old value.
917 * However we propagate rc to caller in case option was
920 if (rc
!= DCCP_FEAT_SP_NOAGREE
)
921 dccp_feat_empty_confirm(dccp_msk(sk
), type
, feature
);
924 /* generate the confirm [if required] */
925 dccp_feat_flush_confirm(sk
);
930 EXPORT_SYMBOL_GPL(dccp_feat_change_recv
);
932 int dccp_feat_confirm_recv(struct sock
*sk
, u8 type
, u8 feature
,
936 struct dccp_opt_pend
*opt
;
937 struct dccp_minisock
*dmsk
= dccp_msk(sk
);
939 int all_confirmed
= 1;
941 /* Ignore Confirm options other than during connection setup */
942 if (sk
->sk_state
!= DCCP_LISTEN
&& sk
->sk_state
!= DCCP_REQUESTING
)
944 dccp_feat_debug(type
, feature
, *val
);
946 /* locate our change request */
948 case DCCPO_CONFIRM_L
: t
= DCCPO_CHANGE_R
; break;
949 case DCCPO_CONFIRM_R
: t
= DCCPO_CHANGE_L
; break;
950 default: DCCP_WARN("invalid type %d\n", type
);
954 /* XXX sanity check feature value */
956 list_for_each_entry(opt
, &dmsk
->dccpms_pending
, dccpop_node
) {
957 if (!opt
->dccpop_conf
&& opt
->dccpop_type
== t
&&
958 opt
->dccpop_feat
== feature
) {
960 dccp_pr_debug("feature %d found\n", opt
->dccpop_feat
);
962 /* XXX do sanity check */
964 opt
->dccpop_conf
= 1;
966 /* We got a confirmation---change the option */
967 dccp_feat_update(sk
, opt
->dccpop_type
,
968 opt
->dccpop_feat
, *val
);
970 /* XXX check the return value of dccp_feat_update */
974 if (!opt
->dccpop_conf
)
979 dccp_pr_debug("%s(%d, ...) never requested\n",
980 dccp_feat_typename(type
), feature
);
984 EXPORT_SYMBOL_GPL(dccp_feat_confirm_recv
);
986 void dccp_feat_clean(struct dccp_minisock
*dmsk
)
988 struct dccp_opt_pend
*opt
, *next
;
990 list_for_each_entry_safe(opt
, next
, &dmsk
->dccpms_pending
,
992 BUG_ON(opt
->dccpop_val
== NULL
);
993 kfree(opt
->dccpop_val
);
995 if (opt
->dccpop_sc
!= NULL
) {
996 BUG_ON(opt
->dccpop_sc
->dccpoc_val
== NULL
);
997 kfree(opt
->dccpop_sc
->dccpoc_val
);
998 kfree(opt
->dccpop_sc
);
1003 INIT_LIST_HEAD(&dmsk
->dccpms_pending
);
1005 list_for_each_entry_safe(opt
, next
, &dmsk
->dccpms_conf
, dccpop_node
) {
1006 BUG_ON(opt
== NULL
);
1007 if (opt
->dccpop_val
!= NULL
)
1008 kfree(opt
->dccpop_val
);
1011 INIT_LIST_HEAD(&dmsk
->dccpms_conf
);
1014 EXPORT_SYMBOL_GPL(dccp_feat_clean
);
1016 /* this is to be called only when a listening sock creates its child. It is
1017 * assumed by the function---the confirm is not duplicated, but rather it is
1020 int dccp_feat_clone(struct sock
*oldsk
, struct sock
*newsk
)
1022 struct dccp_minisock
*olddmsk
= dccp_msk(oldsk
);
1023 struct dccp_minisock
*newdmsk
= dccp_msk(newsk
);
1024 struct dccp_opt_pend
*opt
;
1027 INIT_LIST_HEAD(&newdmsk
->dccpms_pending
);
1028 INIT_LIST_HEAD(&newdmsk
->dccpms_conf
);
1030 list_for_each_entry(opt
, &olddmsk
->dccpms_pending
, dccpop_node
) {
1031 struct dccp_opt_pend
*newopt
;
1032 /* copy the value of the option */
1033 u8
*val
= kmemdup(opt
->dccpop_val
, opt
->dccpop_len
, GFP_ATOMIC
);
1038 newopt
= kmemdup(opt
, sizeof(*newopt
), GFP_ATOMIC
);
1039 if (newopt
== NULL
) {
1044 /* insert the option */
1045 newopt
->dccpop_val
= val
;
1046 list_add_tail(&newopt
->dccpop_node
, &newdmsk
->dccpms_pending
);
1048 /* XXX what happens with backlogs and multiple connections at
1051 /* the master socket no longer needs to worry about confirms */
1052 opt
->dccpop_sc
= NULL
; /* it's not a memleak---new socket has it */
1054 /* reset state for a new socket */
1055 opt
->dccpop_conf
= 0;
1058 /* XXX not doing anything about the conf queue */
1064 dccp_feat_clean(newdmsk
);
1069 EXPORT_SYMBOL_GPL(dccp_feat_clone
);
1071 int dccp_feat_init(struct sock
*sk
)
1073 struct dccp_sock
*dp
= dccp_sk(sk
);
1074 struct dccp_minisock
*dmsk
= dccp_msk(sk
);
1077 INIT_LIST_HEAD(&dmsk
->dccpms_pending
); /* XXX no longer used */
1078 INIT_LIST_HEAD(&dmsk
->dccpms_conf
); /* XXX no longer used */
1081 rc
= __feat_register_sp(&dp
->dccps_featneg
, DCCPF_CCID
, 1, 0,
1082 &dmsk
->dccpms_tx_ccid
, 1);
1087 rc
= __feat_register_sp(&dp
->dccps_featneg
, DCCPF_CCID
, 0, 0,
1088 &dmsk
->dccpms_rx_ccid
, 1);
1093 rc
= __feat_register_nn(&dp
->dccps_featneg
, DCCPF_ACK_RATIO
, 0,
1094 dp
->dccps_l_ack_ratio
);
1099 EXPORT_SYMBOL_GPL(dccp_feat_init
);
1101 #ifdef CONFIG_IP_DCCP_DEBUG
1102 const char *dccp_feat_typename(const u8 type
)
1105 case DCCPO_CHANGE_L
: return("ChangeL");
1106 case DCCPO_CONFIRM_L
: return("ConfirmL");
1107 case DCCPO_CHANGE_R
: return("ChangeR");
1108 case DCCPO_CONFIRM_R
: return("ConfirmR");
1109 /* the following case must not appear in feature negotation */
1110 default: dccp_pr_debug("unknown type %d [BUG!]\n", type
);
1115 EXPORT_SYMBOL_GPL(dccp_feat_typename
);
1117 const char *dccp_feat_name(const u8 feat
)
1119 static const char *feature_names
[] = {
1120 [DCCPF_RESERVED
] = "Reserved",
1121 [DCCPF_CCID
] = "CCID",
1122 [DCCPF_SHORT_SEQNOS
] = "Allow Short Seqnos",
1123 [DCCPF_SEQUENCE_WINDOW
] = "Sequence Window",
1124 [DCCPF_ECN_INCAPABLE
] = "ECN Incapable",
1125 [DCCPF_ACK_RATIO
] = "Ack Ratio",
1126 [DCCPF_SEND_ACK_VECTOR
] = "Send ACK Vector",
1127 [DCCPF_SEND_NDP_COUNT
] = "Send NDP Count",
1128 [DCCPF_MIN_CSUM_COVER
] = "Min. Csum Coverage",
1129 [DCCPF_DATA_CHECKSUM
] = "Send Data Checksum",
1131 if (feat
> DCCPF_DATA_CHECKSUM
&& feat
< DCCPF_MIN_CCID_SPECIFIC
)
1132 return feature_names
[DCCPF_RESERVED
];
1134 if (feat
== DCCPF_SEND_LEV_RATE
)
1135 return "Send Loss Event Rate";
1136 if (feat
>= DCCPF_MIN_CCID_SPECIFIC
)
1137 return "CCID-specific";
1139 return feature_names
[feat
];
1142 EXPORT_SYMBOL_GPL(dccp_feat_name
);
1143 #endif /* CONFIG_IP_DCCP_DEBUG */