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
);
276 * dccp_feat_valid_nn_length - Enforce length constraints on NN options
277 * Length is between 0 and %DCCP_OPTVAL_MAXLEN. Used for outgoing packets only,
278 * incoming options are accepted as long as their values are valid.
280 static u8
dccp_feat_valid_nn_length(u8 feat_num
)
282 if (feat_num
== DCCPF_ACK_RATIO
) /* RFC 4340, 11.3 and 6.6.8 */
284 if (feat_num
== DCCPF_SEQUENCE_WINDOW
) /* RFC 4340, 7.5.2 and 6.5 */
289 static u8
dccp_feat_is_valid_nn_val(u8 feat_num
, u64 val
)
292 case DCCPF_ACK_RATIO
:
293 return val
<= DCCPF_ACK_RATIO_MAX
;
294 case DCCPF_SEQUENCE_WINDOW
:
295 return val
>= DCCPF_SEQ_WMIN
&& val
<= DCCPF_SEQ_WMAX
;
297 return 0; /* feature unknown - so we can't tell */
300 /* check that SP values are within the ranges defined in RFC 4340 */
301 static u8
dccp_feat_is_valid_sp_val(u8 feat_num
, u8 val
)
305 return val
== DCCPC_CCID2
|| val
== DCCPC_CCID3
;
306 /* Type-check Boolean feature values: */
307 case DCCPF_SHORT_SEQNOS
:
308 case DCCPF_ECN_INCAPABLE
:
309 case DCCPF_SEND_ACK_VECTOR
:
310 case DCCPF_SEND_NDP_COUNT
:
311 case DCCPF_DATA_CHECKSUM
:
312 case DCCPF_SEND_LEV_RATE
:
314 case DCCPF_MIN_CSUM_COVER
:
317 return 0; /* feature unknown */
320 static u8
dccp_feat_sp_list_ok(u8 feat_num
, u8
const *sp_list
, u8 sp_len
)
322 if (sp_list
== NULL
|| sp_len
< 1)
325 if (!dccp_feat_is_valid_sp_val(feat_num
, *sp_list
++))
331 * dccp_feat_insert_opts - Generate FN options from current list state
332 * @skb: next sk_buff to be sent to the peer
333 * @dp: for client during handshake and general negotiation
334 * @dreq: used by the server only (all Changes/Confirms in LISTEN/RESPOND)
336 int dccp_feat_insert_opts(struct dccp_sock
*dp
, struct dccp_request_sock
*dreq
,
339 struct list_head
*fn
= dreq
? &dreq
->dreq_featneg
: &dp
->dccps_featneg
;
340 struct dccp_feat_entry
*pos
, *next
;
341 u8 opt
, type
, len
, *ptr
, nn_in_nbo
[DCCP_OPTVAL_MAXLEN
];
344 /* put entries into @skb in the order they appear in the list */
345 list_for_each_entry_safe_reverse(pos
, next
, fn
, node
) {
346 opt
= dccp_feat_genopt(pos
);
347 type
= dccp_feat_type(pos
->feat_num
);
350 if (pos
->empty_confirm
) {
354 if (type
== FEAT_SP
) {
355 len
= pos
->val
.sp
.len
;
356 ptr
= pos
->val
.sp
.vec
;
357 rpt
= pos
->needs_confirm
;
358 } else if (type
== FEAT_NN
) {
359 len
= dccp_feat_valid_nn_length(pos
->feat_num
);
361 dccp_encode_value_var(pos
->val
.nn
, ptr
, len
);
363 DCCP_BUG("unknown feature %u", pos
->feat_num
);
368 if (dccp_insert_fn_opt(skb
, opt
, pos
->feat_num
, ptr
, len
, rpt
))
370 if (pos
->needs_mandatory
&& dccp_insert_option_mandatory(skb
))
373 * Enter CHANGING after transmitting the Change option (6.6.2).
375 if (pos
->state
== FEAT_INITIALISING
)
376 pos
->state
= FEAT_CHANGING
;
382 * __feat_register_nn - Register new NN value on socket
383 * @fn: feature-negotiation list to register with
384 * @feat: an NN feature from %dccp_feature_numbers
385 * @mandatory: use Mandatory option if 1
386 * @nn_val: value to register (restricted to 4 bytes)
387 * Note that NN features are local by definition (RFC 4340, 6.3.2).
389 static int __feat_register_nn(struct list_head
*fn
, u8 feat
,
390 u8 mandatory
, u64 nn_val
)
392 dccp_feat_val fval
= { .nn
= nn_val
};
394 if (dccp_feat_type(feat
) != FEAT_NN
||
395 !dccp_feat_is_valid_nn_val(feat
, nn_val
))
398 /* Don't bother with default values, they will be activated anyway. */
399 if (nn_val
- (u64
)dccp_feat_default_value(feat
) == 0)
402 return dccp_feat_push_change(fn
, feat
, 1, mandatory
, &fval
);
406 * __feat_register_sp - Register new SP value/list on socket
407 * @fn: feature-negotiation list to register with
408 * @feat: an SP feature from %dccp_feature_numbers
409 * @is_local: whether the local (1) or the remote (0) @feat is meant
410 * @mandatory: use Mandatory option if 1
411 * @sp_val: SP value followed by optional preference list
412 * @sp_len: length of @sp_val in bytes
414 static int __feat_register_sp(struct list_head
*fn
, u8 feat
, u8 is_local
,
415 u8 mandatory
, u8
const *sp_val
, u8 sp_len
)
419 if (dccp_feat_type(feat
) != FEAT_SP
||
420 !dccp_feat_sp_list_ok(feat
, sp_val
, sp_len
))
423 /* Avoid negotiating alien CCIDs by only advertising supported ones */
424 if (feat
== DCCPF_CCID
&& !ccid_support_check(sp_val
, sp_len
))
427 if (dccp_feat_clone_sp_val(&fval
, sp_val
, sp_len
))
430 return dccp_feat_push_change(fn
, feat
, is_local
, mandatory
, &fval
);
434 * dccp_feat_register_sp - Register requests to change SP feature values
435 * @sk: client or listening socket
436 * @feat: one of %dccp_feature_numbers
437 * @is_local: whether the local (1) or remote (0) @feat is meant
438 * @list: array of preferred values, in descending order of preference
439 * @len: length of @list in bytes
441 int dccp_feat_register_sp(struct sock
*sk
, u8 feat
, u8 is_local
,
442 u8
const *list
, u8 len
)
443 { /* any changes must be registered before establishing the connection */
444 if (sk
->sk_state
!= DCCP_CLOSED
)
446 if (dccp_feat_type(feat
) != FEAT_SP
)
448 return __feat_register_sp(&dccp_sk(sk
)->dccps_featneg
, feat
, is_local
,
452 /* Analogous to dccp_feat_register_sp(), but for non-negotiable values */
453 int dccp_feat_register_nn(struct sock
*sk
, u8 feat
, u64 val
)
455 /* any changes must be registered before establishing the connection */
456 if (sk
->sk_state
!= DCCP_CLOSED
)
458 if (dccp_feat_type(feat
) != FEAT_NN
)
460 return __feat_register_nn(&dccp_sk(sk
)->dccps_featneg
, feat
, 0, val
);
464 * Tracking features whose value depend on the choice of CCID
466 * This is designed with an extension in mind so that a list walk could be done
467 * before activating any features. However, the existing framework was found to
468 * work satisfactorily up until now, the automatic verification is left open.
469 * When adding new CCIDs, add a corresponding dependency table here.
471 static const struct ccid_dependency
*dccp_feat_ccid_deps(u8 ccid
, bool is_local
)
473 static const struct ccid_dependency ccid2_dependencies
[2][2] = {
475 * CCID2 mandates Ack Vectors (RFC 4341, 4.): as CCID is a TX
476 * feature and Send Ack Vector is an RX feature, `is_local'
477 * needs to be reversed.
479 { /* Dependencies of the receiver-side (remote) CCID2 */
481 .dependent_feat
= DCCPF_SEND_ACK_VECTOR
,
483 .is_mandatory
= true,
488 { /* Dependencies of the sender-side (local) CCID2 */
490 .dependent_feat
= DCCPF_SEND_ACK_VECTOR
,
492 .is_mandatory
= true,
498 static const struct ccid_dependency ccid3_dependencies
[2][5] = {
500 * Dependencies of the receiver-side CCID3
502 { /* locally disable Ack Vectors */
503 .dependent_feat
= DCCPF_SEND_ACK_VECTOR
,
505 .is_mandatory
= false,
508 { /* see below why Send Loss Event Rate is on */
509 .dependent_feat
= DCCPF_SEND_LEV_RATE
,
511 .is_mandatory
= true,
514 { /* NDP Count is needed as per RFC 4342, 6.1.1 */
515 .dependent_feat
= DCCPF_SEND_NDP_COUNT
,
517 .is_mandatory
= true,
523 * CCID3 at the TX side: we request that the HC-receiver
524 * will not send Ack Vectors (they will be ignored, so
525 * Mandatory is not set); we enable Send Loss Event Rate
526 * (Mandatory since the implementation does not support
527 * the Loss Intervals option of RFC 4342, 8.6).
528 * The last two options are for peer's information only.
531 .dependent_feat
= DCCPF_SEND_ACK_VECTOR
,
533 .is_mandatory
= false,
537 .dependent_feat
= DCCPF_SEND_LEV_RATE
,
539 .is_mandatory
= true,
542 { /* this CCID does not support Ack Ratio */
543 .dependent_feat
= DCCPF_ACK_RATIO
,
545 .is_mandatory
= false,
548 { /* tell receiver we are sending NDP counts */
549 .dependent_feat
= DCCPF_SEND_NDP_COUNT
,
551 .is_mandatory
= false,
559 return ccid2_dependencies
[is_local
];
561 return ccid3_dependencies
[is_local
];
568 * dccp_feat_propagate_ccid - Resolve dependencies of features on choice of CCID
569 * @fn: feature-negotiation list to update
570 * @id: CCID number to track
571 * @is_local: whether TX CCID (1) or RX CCID (0) is meant
572 * This function needs to be called after registering all other features.
574 static int dccp_feat_propagate_ccid(struct list_head
*fn
, u8 id
, bool is_local
)
576 const struct ccid_dependency
*table
= dccp_feat_ccid_deps(id
, is_local
);
577 int i
, rc
= (table
== NULL
);
579 for (i
= 0; rc
== 0 && table
[i
].dependent_feat
!= DCCPF_RESERVED
; i
++)
580 if (dccp_feat_type(table
[i
].dependent_feat
) == FEAT_SP
)
581 rc
= __feat_register_sp(fn
, table
[i
].dependent_feat
,
583 table
[i
].is_mandatory
,
586 rc
= __feat_register_nn(fn
, table
[i
].dependent_feat
,
587 table
[i
].is_mandatory
,
593 * dccp_feat_finalise_settings - Finalise settings before starting negotiation
594 * @dp: client or listening socket (settings will be inherited)
595 * This is called after all registrations (socket initialisation, sysctls, and
596 * sockopt calls), and before sending the first packet containing Change options
597 * (ie. client-Request or server-Response), to ensure internal consistency.
599 int dccp_feat_finalise_settings(struct dccp_sock
*dp
)
601 struct list_head
*fn
= &dp
->dccps_featneg
;
602 struct dccp_feat_entry
*entry
;
603 int i
= 2, ccids
[2] = { -1, -1 };
607 * 1) not useful to propagate CCID settings if this host advertises more
608 * than one CCID: the choice of CCID may still change - if this is
609 * the client, or if this is the server and the client sends
610 * singleton CCID values.
611 * 2) since is that propagate_ccid changes the list, we defer changing
612 * the sorted list until after the traversal.
614 list_for_each_entry(entry
, fn
, node
)
615 if (entry
->feat_num
== DCCPF_CCID
&& entry
->val
.sp
.len
== 1)
616 ccids
[entry
->is_local
] = entry
->val
.sp
.vec
[0];
618 if (ccids
[i
] > 0 && dccp_feat_propagate_ccid(fn
, ccids
[i
], i
))
624 * dccp_feat_server_ccid_dependencies - Resolve CCID-dependent features
625 * It is the server which resolves the dependencies once the CCID has been
626 * fully negotiated. If no CCID has been negotiated, it uses the default CCID.
628 int dccp_feat_server_ccid_dependencies(struct dccp_request_sock
*dreq
)
630 struct list_head
*fn
= &dreq
->dreq_featneg
;
631 struct dccp_feat_entry
*entry
;
634 for (is_local
= 0; is_local
<= 1; is_local
++) {
635 entry
= dccp_feat_list_lookup(fn
, DCCPF_CCID
, is_local
);
637 if (entry
!= NULL
&& !entry
->empty_confirm
)
638 ccid
= entry
->val
.sp
.vec
[0];
640 ccid
= dccp_feat_default_value(DCCPF_CCID
);
642 if (dccp_feat_propagate_ccid(fn
, ccid
, is_local
))
648 static int dccp_feat_update_ccid(struct sock
*sk
, u8 type
, u8 new_ccid_nr
)
650 struct dccp_sock
*dp
= dccp_sk(sk
);
651 struct dccp_minisock
*dmsk
= dccp_msk(sk
);
652 /* figure out if we are changing our CCID or the peer's */
653 const int rx
= type
== DCCPO_CHANGE_R
;
654 const u8 ccid_nr
= rx
? dmsk
->dccpms_rx_ccid
: dmsk
->dccpms_tx_ccid
;
655 struct ccid
*new_ccid
;
657 /* Check if nothing is being changed. */
658 if (ccid_nr
== new_ccid_nr
)
661 new_ccid
= ccid_new(new_ccid_nr
, sk
, rx
, GFP_ATOMIC
);
662 if (new_ccid
== NULL
)
666 ccid_hc_rx_delete(dp
->dccps_hc_rx_ccid
, sk
);
667 dp
->dccps_hc_rx_ccid
= new_ccid
;
668 dmsk
->dccpms_rx_ccid
= new_ccid_nr
;
670 ccid_hc_tx_delete(dp
->dccps_hc_tx_ccid
, sk
);
671 dp
->dccps_hc_tx_ccid
= new_ccid
;
672 dmsk
->dccpms_tx_ccid
= new_ccid_nr
;
678 static int dccp_feat_update(struct sock
*sk
, u8 type
, u8 feat
, u8 val
)
680 dccp_feat_debug(type
, feat
, val
);
684 return dccp_feat_update_ccid(sk
, type
, val
);
686 dccp_pr_debug("UNIMPLEMENTED: %s(%d, ...)\n",
687 dccp_feat_typename(type
), feat
);
693 /* Select the first entry in @servlist that also occurs in @clilist (6.3.1) */
694 static int dccp_feat_preflist_match(u8
*servlist
, u8 slen
, u8
*clilist
, u8 clen
)
698 for (s
= 0; s
< slen
; s
++)
699 for (c
= 0; c
< clen
; c
++)
700 if (servlist
[s
] == clilist
[c
])
706 * dccp_feat_prefer - Move preferred entry to the start of array
707 * Reorder the @array_len elements in @array so that @preferred_value comes
708 * first. Returns >0 to indicate that @preferred_value does occur in @array.
710 static u8
dccp_feat_prefer(u8 preferred_value
, u8
*array
, u8 array_len
)
712 u8 i
, does_occur
= 0;
715 for (i
= 0; i
< array_len
; i
++)
716 if (array
[i
] == preferred_value
) {
721 array
[0] = preferred_value
;
727 * dccp_feat_reconcile - Reconcile SP preference lists
728 * @fval: SP list to reconcile into
729 * @arr: received SP preference list
730 * @len: length of @arr in bytes
731 * @is_server: whether this side is the server (and @fv is the server's list)
732 * @reorder: whether to reorder the list in @fv after reconciling with @arr
733 * When successful, > 0 is returned and the reconciled list is in @fval.
734 * A value of 0 means that negotiation failed (no shared entry).
736 static int dccp_feat_reconcile(dccp_feat_val
*fv
, u8
*arr
, u8 len
,
737 bool is_server
, bool reorder
)
741 if (!fv
->sp
.vec
|| !arr
) {
742 DCCP_CRIT("NULL feature value or array");
747 rc
= dccp_feat_preflist_match(fv
->sp
.vec
, fv
->sp
.len
, arr
, len
);
749 rc
= dccp_feat_preflist_match(arr
, len
, fv
->sp
.vec
, fv
->sp
.len
);
757 * Reorder list: used for activating features and in dccp_insert_fn_opt.
759 return dccp_feat_prefer(rc
, fv
->sp
.vec
, fv
->sp
.len
);
762 #ifdef __this_is_the_old_framework_and_will_be_removed_later_in_a_subsequent_patch
763 static int dccp_feat_reconcile(struct sock
*sk
, struct dccp_opt_pend
*opt
,
766 struct dccp_sock
*dp
= dccp_sk(sk
);
767 u8
*spref
, slen
, *res
= NULL
;
768 int i
, j
, rc
, agree
= 1;
770 BUG_ON(rpref
== NULL
);
772 /* check if we are the black sheep */
773 if (dp
->dccps_role
== DCCP_ROLE_CLIENT
) {
776 rpref
= opt
->dccpop_val
;
777 rlen
= opt
->dccpop_len
;
779 spref
= opt
->dccpop_val
;
780 slen
= opt
->dccpop_len
;
783 * Now we have server preference list in spref and client preference in
786 BUG_ON(spref
== NULL
);
787 BUG_ON(rpref
== NULL
);
789 /* FIXME sanity check vals */
791 /* Are values in any order? XXX Lame "algorithm" here */
792 for (i
= 0; i
< slen
; i
++) {
793 for (j
= 0; j
< rlen
; j
++) {
794 if (spref
[i
] == rpref
[j
]) {
803 /* we didn't agree on anything */
805 /* confirm previous value */
806 switch (opt
->dccpop_feat
) {
808 /* XXX did i get this right? =P */
809 if (opt
->dccpop_type
== DCCPO_CHANGE_L
)
810 res
= &dccp_msk(sk
)->dccpms_tx_ccid
;
812 res
= &dccp_msk(sk
)->dccpms_rx_ccid
;
816 DCCP_BUG("Fell through, feat=%d", opt
->dccpop_feat
);
817 /* XXX implement res */
821 dccp_pr_debug("Don't agree... reconfirming %d\n", *res
);
822 agree
= 0; /* this is used for mandatory options... */
825 /* need to put result and our preference list */
826 rlen
= 1 + opt
->dccpop_len
;
827 rpref
= kmalloc(rlen
, GFP_ATOMIC
);
832 memcpy(&rpref
[1], opt
->dccpop_val
, opt
->dccpop_len
);
834 /* put it in the "confirm queue" */
835 if (opt
->dccpop_sc
== NULL
) {
836 opt
->dccpop_sc
= kmalloc(sizeof(*opt
->dccpop_sc
), GFP_ATOMIC
);
837 if (opt
->dccpop_sc
== NULL
) {
842 /* recycle the confirm slot */
843 BUG_ON(opt
->dccpop_sc
->dccpoc_val
== NULL
);
844 kfree(opt
->dccpop_sc
->dccpoc_val
);
845 dccp_pr_debug("recycling confirm slot\n");
847 memset(opt
->dccpop_sc
, 0, sizeof(*opt
->dccpop_sc
));
849 opt
->dccpop_sc
->dccpoc_val
= rpref
;
850 opt
->dccpop_sc
->dccpoc_len
= rlen
;
852 /* update the option on our side [we are about to send the confirm] */
853 rc
= dccp_feat_update(sk
, opt
->dccpop_type
, opt
->dccpop_feat
, *res
);
855 kfree(opt
->dccpop_sc
->dccpoc_val
);
856 kfree(opt
->dccpop_sc
);
857 opt
->dccpop_sc
= NULL
;
861 dccp_pr_debug("Will confirm %d\n", *rpref
);
863 /* say we want to change to X but we just got a confirm X, suppress our
866 if (!opt
->dccpop_conf
) {
867 if (*opt
->dccpop_val
== *res
)
868 opt
->dccpop_conf
= 1;
869 dccp_pr_debug("won't ask for change of same feature\n");
872 return agree
? 0 : DCCP_FEAT_SP_NOAGREE
; /* used for mandatory opts */
875 static int dccp_feat_sp(struct sock
*sk
, u8 type
, u8 feature
, u8
*val
, u8 len
)
877 struct dccp_minisock
*dmsk
= dccp_msk(sk
);
878 struct dccp_opt_pend
*opt
;
883 * We received a CHANGE. We gotta match it against our own preference
884 * list. If we got a CHANGE_R it means it's a change for us, so we need
885 * to compare our CHANGE_L list.
887 if (type
== DCCPO_CHANGE_L
)
892 /* find our preference list for this feature */
893 list_for_each_entry(opt
, &dmsk
->dccpms_pending
, dccpop_node
) {
894 if (opt
->dccpop_type
!= t
|| opt
->dccpop_feat
!= feature
)
897 /* find the winner from the two preference lists */
898 rc
= dccp_feat_reconcile(sk
, opt
, val
, len
);
902 /* We didn't deal with the change. This can happen if we have no
903 * preference list for the feature. In fact, it just shouldn't
904 * happen---if we understand a feature, we should have a preference list
905 * with at least the default value.
912 static int dccp_feat_nn(struct sock
*sk
, u8 type
, u8 feature
, u8
*val
, u8 len
)
914 struct dccp_opt_pend
*opt
;
915 struct dccp_minisock
*dmsk
= dccp_msk(sk
);
919 /* NN features must be Change L (sec. 6.3.2) */
920 if (type
!= DCCPO_CHANGE_L
) {
921 dccp_pr_debug("received %s for NN feature %d\n",
922 dccp_feat_typename(type
), feature
);
926 /* XXX sanity check opt val */
928 /* copy option so we can confirm it */
929 opt
= kzalloc(sizeof(*opt
), GFP_ATOMIC
);
933 copy
= kmemdup(val
, len
, GFP_ATOMIC
);
939 opt
->dccpop_type
= DCCPO_CONFIRM_R
; /* NN can only confirm R */
940 opt
->dccpop_feat
= feature
;
941 opt
->dccpop_val
= copy
;
942 opt
->dccpop_len
= len
;
945 rc
= dccp_feat_update(sk
, type
, feature
, *val
);
947 kfree(opt
->dccpop_val
);
952 dccp_feat_debug(type
, feature
, *copy
);
954 list_add_tail(&opt
->dccpop_node
, &dmsk
->dccpms_conf
);
960 static void dccp_feat_empty_confirm(struct dccp_minisock
*dmsk
,
963 /* XXX check if other confirms for that are queued and recycle slot */
964 struct dccp_opt_pend
*opt
= kzalloc(sizeof(*opt
), GFP_ATOMIC
);
967 /* XXX what do we do? Ignoring should be fine. It's a change
975 opt
->dccpop_type
= DCCPO_CONFIRM_R
;
978 opt
->dccpop_type
= DCCPO_CONFIRM_L
;
981 DCCP_WARN("invalid type %d\n", type
);
985 opt
->dccpop_feat
= feature
;
986 opt
->dccpop_val
= NULL
;
990 dccp_pr_debug("Empty %s(%d)\n", dccp_feat_typename(type
), feature
);
992 list_add_tail(&opt
->dccpop_node
, &dmsk
->dccpms_conf
);
995 static void dccp_feat_flush_confirm(struct sock
*sk
)
997 struct dccp_minisock
*dmsk
= dccp_msk(sk
);
998 /* Check if there is anything to confirm in the first place */
999 int yes
= !list_empty(&dmsk
->dccpms_conf
);
1002 struct dccp_opt_pend
*opt
;
1004 list_for_each_entry(opt
, &dmsk
->dccpms_pending
, dccpop_node
) {
1005 if (opt
->dccpop_conf
) {
1015 /* OK there is something to confirm... */
1016 /* XXX check if packet is in flight? Send delayed ack?? */
1017 if (sk
->sk_state
== DCCP_OPEN
)
1021 int dccp_feat_change_recv(struct sock
*sk
, u8 type
, u8 feature
, u8
*val
, u8 len
)
1025 /* Ignore Change requests other than during connection setup */
1026 if (sk
->sk_state
!= DCCP_LISTEN
&& sk
->sk_state
!= DCCP_REQUESTING
)
1028 dccp_feat_debug(type
, feature
, *val
);
1030 /* figure out if it's SP or NN feature */
1032 /* deal with SP features */
1034 /* XXX Obsoleted by next patch
1035 rc = dccp_feat_sp(sk, type, feature, val, len); */
1038 /* deal with NN features */
1039 case DCCPF_ACK_RATIO
:
1040 /* XXX Obsoleted by next patch
1041 rc = dccp_feat_nn(sk, type, feature, val, len); */
1044 /* XXX implement other features */
1046 dccp_pr_debug("UNIMPLEMENTED: not handling %s(%d, ...)\n",
1047 dccp_feat_typename(type
), feature
);
1052 /* check if there were problems changing features */
1054 /* If we don't agree on SP, we sent a confirm for old value.
1055 * However we propagate rc to caller in case option was
1058 if (rc
!= DCCP_FEAT_SP_NOAGREE
)
1059 dccp_feat_empty_confirm(dccp_msk(sk
), type
, feature
);
1062 /* generate the confirm [if required] */
1063 dccp_feat_flush_confirm(sk
);
1068 EXPORT_SYMBOL_GPL(dccp_feat_change_recv
);
1070 int dccp_feat_confirm_recv(struct sock
*sk
, u8 type
, u8 feature
,
1074 struct dccp_opt_pend
*opt
;
1075 struct dccp_minisock
*dmsk
= dccp_msk(sk
);
1077 int all_confirmed
= 1;
1079 /* Ignore Confirm options other than during connection setup */
1080 if (sk
->sk_state
!= DCCP_LISTEN
&& sk
->sk_state
!= DCCP_REQUESTING
)
1082 dccp_feat_debug(type
, feature
, *val
);
1084 /* locate our change request */
1086 case DCCPO_CONFIRM_L
: t
= DCCPO_CHANGE_R
; break;
1087 case DCCPO_CONFIRM_R
: t
= DCCPO_CHANGE_L
; break;
1088 default: DCCP_WARN("invalid type %d\n", type
);
1092 /* XXX sanity check feature value */
1094 list_for_each_entry(opt
, &dmsk
->dccpms_pending
, dccpop_node
) {
1095 if (!opt
->dccpop_conf
&& opt
->dccpop_type
== t
&&
1096 opt
->dccpop_feat
== feature
) {
1098 dccp_pr_debug("feature %d found\n", opt
->dccpop_feat
);
1100 /* XXX do sanity check */
1102 opt
->dccpop_conf
= 1;
1104 /* We got a confirmation---change the option */
1105 dccp_feat_update(sk
, opt
->dccpop_type
,
1106 opt
->dccpop_feat
, *val
);
1108 /* XXX check the return value of dccp_feat_update */
1112 if (!opt
->dccpop_conf
)
1117 dccp_pr_debug("%s(%d, ...) never requested\n",
1118 dccp_feat_typename(type
), feature
);
1122 EXPORT_SYMBOL_GPL(dccp_feat_confirm_recv
);
1124 void dccp_feat_clean(struct dccp_minisock
*dmsk
)
1126 struct dccp_opt_pend
*opt
, *next
;
1128 list_for_each_entry_safe(opt
, next
, &dmsk
->dccpms_pending
,
1130 BUG_ON(opt
->dccpop_val
== NULL
);
1131 kfree(opt
->dccpop_val
);
1133 if (opt
->dccpop_sc
!= NULL
) {
1134 BUG_ON(opt
->dccpop_sc
->dccpoc_val
== NULL
);
1135 kfree(opt
->dccpop_sc
->dccpoc_val
);
1136 kfree(opt
->dccpop_sc
);
1141 INIT_LIST_HEAD(&dmsk
->dccpms_pending
);
1143 list_for_each_entry_safe(opt
, next
, &dmsk
->dccpms_conf
, dccpop_node
) {
1144 BUG_ON(opt
== NULL
);
1145 if (opt
->dccpop_val
!= NULL
)
1146 kfree(opt
->dccpop_val
);
1149 INIT_LIST_HEAD(&dmsk
->dccpms_conf
);
1152 EXPORT_SYMBOL_GPL(dccp_feat_clean
);
1154 /* this is to be called only when a listening sock creates its child. It is
1155 * assumed by the function---the confirm is not duplicated, but rather it is
1158 int dccp_feat_clone(struct sock
*oldsk
, struct sock
*newsk
)
1160 struct dccp_minisock
*olddmsk
= dccp_msk(oldsk
);
1161 struct dccp_minisock
*newdmsk
= dccp_msk(newsk
);
1162 struct dccp_opt_pend
*opt
;
1165 INIT_LIST_HEAD(&newdmsk
->dccpms_pending
);
1166 INIT_LIST_HEAD(&newdmsk
->dccpms_conf
);
1168 list_for_each_entry(opt
, &olddmsk
->dccpms_pending
, dccpop_node
) {
1169 struct dccp_opt_pend
*newopt
;
1170 /* copy the value of the option */
1171 u8
*val
= kmemdup(opt
->dccpop_val
, opt
->dccpop_len
, GFP_ATOMIC
);
1176 newopt
= kmemdup(opt
, sizeof(*newopt
), GFP_ATOMIC
);
1177 if (newopt
== NULL
) {
1182 /* insert the option */
1183 newopt
->dccpop_val
= val
;
1184 list_add_tail(&newopt
->dccpop_node
, &newdmsk
->dccpms_pending
);
1186 /* XXX what happens with backlogs and multiple connections at
1189 /* the master socket no longer needs to worry about confirms */
1190 opt
->dccpop_sc
= NULL
; /* it's not a memleak---new socket has it */
1192 /* reset state for a new socket */
1193 opt
->dccpop_conf
= 0;
1196 /* XXX not doing anything about the conf queue */
1202 dccp_feat_clean(newdmsk
);
1207 EXPORT_SYMBOL_GPL(dccp_feat_clone
);
1209 int dccp_feat_init(struct sock
*sk
)
1211 struct dccp_sock
*dp
= dccp_sk(sk
);
1212 struct dccp_minisock
*dmsk
= dccp_msk(sk
);
1215 INIT_LIST_HEAD(&dmsk
->dccpms_pending
); /* XXX no longer used */
1216 INIT_LIST_HEAD(&dmsk
->dccpms_conf
); /* XXX no longer used */
1219 rc
= __feat_register_sp(&dp
->dccps_featneg
, DCCPF_CCID
, 1, 0,
1220 &dmsk
->dccpms_tx_ccid
, 1);
1225 rc
= __feat_register_sp(&dp
->dccps_featneg
, DCCPF_CCID
, 0, 0,
1226 &dmsk
->dccpms_rx_ccid
, 1);
1231 rc
= __feat_register_nn(&dp
->dccps_featneg
, DCCPF_ACK_RATIO
, 0,
1232 dp
->dccps_l_ack_ratio
);
1237 EXPORT_SYMBOL_GPL(dccp_feat_init
);
1239 #ifdef CONFIG_IP_DCCP_DEBUG
1240 const char *dccp_feat_typename(const u8 type
)
1243 case DCCPO_CHANGE_L
: return("ChangeL");
1244 case DCCPO_CONFIRM_L
: return("ConfirmL");
1245 case DCCPO_CHANGE_R
: return("ChangeR");
1246 case DCCPO_CONFIRM_R
: return("ConfirmR");
1247 /* the following case must not appear in feature negotation */
1248 default: dccp_pr_debug("unknown type %d [BUG!]\n", type
);
1253 EXPORT_SYMBOL_GPL(dccp_feat_typename
);
1255 const char *dccp_feat_name(const u8 feat
)
1257 static const char *feature_names
[] = {
1258 [DCCPF_RESERVED
] = "Reserved",
1259 [DCCPF_CCID
] = "CCID",
1260 [DCCPF_SHORT_SEQNOS
] = "Allow Short Seqnos",
1261 [DCCPF_SEQUENCE_WINDOW
] = "Sequence Window",
1262 [DCCPF_ECN_INCAPABLE
] = "ECN Incapable",
1263 [DCCPF_ACK_RATIO
] = "Ack Ratio",
1264 [DCCPF_SEND_ACK_VECTOR
] = "Send ACK Vector",
1265 [DCCPF_SEND_NDP_COUNT
] = "Send NDP Count",
1266 [DCCPF_MIN_CSUM_COVER
] = "Min. Csum Coverage",
1267 [DCCPF_DATA_CHECKSUM
] = "Send Data Checksum",
1269 if (feat
> DCCPF_DATA_CHECKSUM
&& feat
< DCCPF_MIN_CCID_SPECIFIC
)
1270 return feature_names
[DCCPF_RESERVED
];
1272 if (feat
== DCCPF_SEND_LEV_RATE
)
1273 return "Send Loss Event Rate";
1274 if (feat
>= DCCPF_MIN_CCID_SPECIFIC
)
1275 return "CCID-specific";
1277 return feature_names
[feat
];
1280 EXPORT_SYMBOL_GPL(dccp_feat_name
);
1281 #endif /* CONFIG_IP_DCCP_DEBUG */