Commit | Line | Data |
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7c657876 ACM |
1 | /* |
2 | * net/dccp/options.c | |
3 | * | |
4 | * An implementation of the DCCP protocol | |
5 | * Aristeu Sergio Rozanski Filho <aris@cathedrallabs.org> | |
6 | * Arnaldo Carvalho de Melo <acme@ghostprotocols.net> | |
7 | * | |
8 | * This program is free software; you can redistribute it and/or | |
9 | * modify it under the terms of the GNU General Public License | |
10 | * as published by the Free Software Foundation; either version | |
11 | * 2 of the License, or (at your option) any later version. | |
12 | */ | |
13 | #include <linux/config.h> | |
14 | #include <linux/dccp.h> | |
15 | #include <linux/module.h> | |
16 | #include <linux/types.h> | |
17 | #include <linux/kernel.h> | |
18 | #include <linux/skbuff.h> | |
19 | ||
20 | #include "ccid.h" | |
21 | #include "dccp.h" | |
22 | ||
23 | static void dccp_ackpkts_check_rcv_ackvector(struct dccp_ackpkts *ap, | |
24 | struct sock *sk, | |
25 | const u64 ackno, | |
26 | const unsigned char len, | |
27 | const unsigned char *vector); | |
28 | ||
29 | /* stores the default values for new connection. may be changed with sysctl */ | |
30 | static const struct dccp_options dccpo_default_values = { | |
31 | .dccpo_sequence_window = DCCPF_INITIAL_SEQUENCE_WINDOW, | |
32 | .dccpo_ccid = DCCPF_INITIAL_CCID, | |
33 | .dccpo_send_ack_vector = DCCPF_INITIAL_SEND_ACK_VECTOR, | |
34 | .dccpo_send_ndp_count = DCCPF_INITIAL_SEND_NDP_COUNT, | |
35 | }; | |
36 | ||
37 | void dccp_options_init(struct dccp_options *dccpo) | |
38 | { | |
39 | memcpy(dccpo, &dccpo_default_values, sizeof(*dccpo)); | |
40 | } | |
41 | ||
42 | static u32 dccp_decode_value_var(const unsigned char *bf, const u8 len) | |
43 | { | |
44 | u32 value = 0; | |
45 | ||
46 | if (len > 3) | |
47 | value += *bf++ << 24; | |
48 | if (len > 2) | |
49 | value += *bf++ << 16; | |
50 | if (len > 1) | |
51 | value += *bf++ << 8; | |
52 | if (len > 0) | |
53 | value += *bf; | |
54 | ||
55 | return value; | |
56 | } | |
57 | ||
58 | int dccp_parse_options(struct sock *sk, struct sk_buff *skb) | |
59 | { | |
60 | struct dccp_sock *dp = dccp_sk(sk); | |
61 | #ifdef DCCP_DEBUG | |
62 | const char *debug_prefix = dp->dccps_role == DCCP_ROLE_CLIENT ? "CLIENT rx opt: " : | |
63 | "server rx opt: "; | |
64 | #endif | |
65 | const struct dccp_hdr *dh = dccp_hdr(skb); | |
66 | const u8 pkt_type = DCCP_SKB_CB(skb)->dccpd_type; | |
67 | unsigned char *options = (unsigned char *)dh + dccp_hdr_len(skb); | |
68 | unsigned char *opt_ptr = options; | |
69 | const unsigned char *opt_end = (unsigned char *)dh + (dh->dccph_doff * 4); | |
70 | struct dccp_options_received *opt_recv = &dp->dccps_options_received; | |
71 | unsigned char opt, len; | |
72 | unsigned char *value; | |
73 | ||
74 | memset(opt_recv, 0, sizeof(*opt_recv)); | |
75 | ||
76 | while (opt_ptr != opt_end) { | |
77 | opt = *opt_ptr++; | |
78 | len = 0; | |
79 | value = NULL; | |
80 | ||
81 | /* Check if this isn't a single byte option */ | |
82 | if (opt > DCCPO_MAX_RESERVED) { | |
83 | if (opt_ptr == opt_end) | |
84 | goto out_invalid_option; | |
85 | ||
86 | len = *opt_ptr++; | |
87 | if (len < 3) | |
88 | goto out_invalid_option; | |
89 | /* | |
90 | * Remove the type and len fields, leaving | |
91 | * just the value size | |
92 | */ | |
93 | len -= 2; | |
94 | value = opt_ptr; | |
95 | opt_ptr += len; | |
96 | ||
97 | if (opt_ptr > opt_end) | |
98 | goto out_invalid_option; | |
99 | } | |
100 | ||
101 | switch (opt) { | |
102 | case DCCPO_PADDING: | |
103 | break; | |
104 | case DCCPO_NDP_COUNT: | |
105 | if (len > 3) | |
106 | goto out_invalid_option; | |
107 | ||
108 | opt_recv->dccpor_ndp = dccp_decode_value_var(value, len); | |
109 | dccp_pr_debug("%sNDP count=%d\n", debug_prefix, opt_recv->dccpor_ndp); | |
110 | break; | |
111 | case DCCPO_ACK_VECTOR_0: | |
112 | if (len > DCCP_MAX_ACK_VECTOR_LEN) | |
113 | goto out_invalid_option; | |
114 | ||
115 | if (pkt_type == DCCP_PKT_DATA) | |
116 | continue; | |
117 | ||
118 | opt_recv->dccpor_ack_vector_len = len; | |
119 | opt_recv->dccpor_ack_vector_idx = value - options; | |
120 | ||
121 | dccp_pr_debug("%sACK vector 0, len=%d, ack_ackno=%llu\n", | |
122 | debug_prefix, len, DCCP_SKB_CB(skb)->dccpd_ack_seq); | |
123 | dccp_ackvector_print(DCCP_SKB_CB(skb)->dccpd_ack_seq, | |
124 | value, len); | |
125 | dccp_ackpkts_check_rcv_ackvector(dp->dccps_hc_rx_ackpkts, sk, | |
126 | DCCP_SKB_CB(skb)->dccpd_ack_seq, | |
127 | len, value); | |
128 | break; | |
129 | case DCCPO_TIMESTAMP: | |
130 | if (len != 4) | |
131 | goto out_invalid_option; | |
132 | ||
133 | opt_recv->dccpor_timestamp = ntohl(*(u32 *)value); | |
134 | ||
135 | dp->dccps_timestamp_echo = opt_recv->dccpor_timestamp; | |
136 | dp->dccps_timestamp_time = jiffies; | |
137 | ||
138 | dccp_pr_debug("%sTIMESTAMP=%u, ackno=%llu\n", | |
139 | debug_prefix, opt_recv->dccpor_timestamp, | |
140 | DCCP_SKB_CB(skb)->dccpd_ack_seq); | |
141 | break; | |
142 | case DCCPO_TIMESTAMP_ECHO: | |
143 | if (len < 4 || len > 8) | |
144 | goto out_invalid_option; | |
145 | ||
146 | opt_recv->dccpor_timestamp_echo = ntohl(*(u32 *)value); | |
147 | ||
148 | dccp_pr_debug("%sTIMESTAMP_ECHO=%u, len=%d, ackno=%llu, diff=%u\n", | |
149 | debug_prefix, opt_recv->dccpor_timestamp_echo, | |
150 | len + 2, DCCP_SKB_CB(skb)->dccpd_ack_seq, | |
151 | tcp_time_stamp - opt_recv->dccpor_timestamp_echo); | |
152 | ||
153 | opt_recv->dccpor_elapsed_time = dccp_decode_value_var(value + 4, len - 4); | |
154 | dccp_pr_debug("%sTIMESTAMP_ECHO ELAPSED_TIME=%d\n", debug_prefix, | |
155 | opt_recv->dccpor_elapsed_time); | |
156 | break; | |
157 | case DCCPO_ELAPSED_TIME: | |
158 | if (len > 4) | |
159 | goto out_invalid_option; | |
160 | ||
161 | if (pkt_type == DCCP_PKT_DATA) | |
162 | continue; | |
163 | opt_recv->dccpor_elapsed_time = dccp_decode_value_var(value, len); | |
164 | dccp_pr_debug("%sELAPSED_TIME=%d\n", debug_prefix, | |
165 | opt_recv->dccpor_elapsed_time); | |
166 | break; | |
167 | /* | |
168 | * From draft-ietf-dccp-spec-11.txt: | |
169 | * | |
170 | * Option numbers 128 through 191 are for options sent from the HC- | |
171 | * Sender to the HC-Receiver; option numbers 192 through 255 are for | |
172 | * options sent from the HC-Receiver to the HC-Sender. | |
173 | */ | |
174 | case 128 ... 191: { | |
175 | const u16 idx = value - options; | |
176 | ||
177 | if (ccid_hc_rx_parse_options(dp->dccps_hc_rx_ccid, sk, opt, len, idx, value) != 0) | |
178 | goto out_invalid_option; | |
179 | } | |
180 | break; | |
181 | case 192 ... 255: { | |
182 | const u16 idx = value - options; | |
183 | ||
184 | if (ccid_hc_tx_parse_options(dp->dccps_hc_tx_ccid, sk, opt, len, idx, value) != 0) | |
185 | goto out_invalid_option; | |
186 | } | |
187 | break; | |
188 | default: | |
189 | pr_info("DCCP(%p): option %d(len=%d) not implemented, ignoring\n", | |
190 | sk, opt, len); | |
191 | break; | |
192 | } | |
193 | } | |
194 | ||
195 | return 0; | |
196 | ||
197 | out_invalid_option: | |
198 | DCCP_INC_STATS_BH(DCCP_MIB_INVALIDOPT); | |
199 | DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_OPTION_ERROR; | |
200 | pr_info("DCCP(%p): invalid option %d, len=%d\n", sk, opt, len); | |
201 | return -1; | |
202 | } | |
203 | ||
204 | static void dccp_encode_value_var(const u32 value, unsigned char *to, | |
205 | const unsigned int len) | |
206 | { | |
207 | if (len > 3) | |
208 | *to++ = (value & 0xFF000000) >> 24; | |
209 | if (len > 2) | |
210 | *to++ = (value & 0xFF0000) >> 16; | |
211 | if (len > 1) | |
212 | *to++ = (value & 0xFF00) >> 8; | |
213 | if (len > 0) | |
214 | *to++ = (value & 0xFF); | |
215 | } | |
216 | ||
217 | static inline int dccp_ndp_len(const int ndp) | |
218 | { | |
219 | return likely(ndp <= 0xFF) ? 1 : ndp <= 0xFFFF ? 2 : 3; | |
220 | } | |
221 | ||
222 | void dccp_insert_option(struct sock *sk, struct sk_buff *skb, | |
223 | const unsigned char option, | |
224 | const void *value, const unsigned char len) | |
225 | { | |
226 | unsigned char *to; | |
227 | ||
228 | if (DCCP_SKB_CB(skb)->dccpd_opt_len + len + 2 > DCCP_MAX_OPT_LEN) { | |
229 | LIMIT_NETDEBUG(pr_info("DCCP: packet too small to insert %d option!\n", option)); | |
230 | return; | |
231 | } | |
232 | ||
233 | DCCP_SKB_CB(skb)->dccpd_opt_len += len + 2; | |
234 | ||
235 | to = skb_push(skb, len + 2); | |
236 | *to++ = option; | |
237 | *to++ = len + 2; | |
238 | ||
239 | memcpy(to, value, len); | |
240 | } | |
241 | ||
242 | EXPORT_SYMBOL_GPL(dccp_insert_option); | |
243 | ||
244 | static void dccp_insert_option_ndp(struct sock *sk, struct sk_buff *skb) | |
245 | { | |
246 | struct dccp_sock *dp = dccp_sk(sk); | |
247 | int ndp = dp->dccps_ndp_count; | |
248 | ||
249 | if (dccp_non_data_packet(skb)) | |
250 | ++dp->dccps_ndp_count; | |
251 | else | |
252 | dp->dccps_ndp_count = 0; | |
253 | ||
254 | if (ndp > 0) { | |
255 | unsigned char *ptr; | |
256 | const int ndp_len = dccp_ndp_len(ndp); | |
257 | const int len = ndp_len + 2; | |
258 | ||
259 | if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN) | |
260 | return; | |
261 | ||
262 | DCCP_SKB_CB(skb)->dccpd_opt_len += len; | |
263 | ||
264 | ptr = skb_push(skb, len); | |
265 | *ptr++ = DCCPO_NDP_COUNT; | |
266 | *ptr++ = len; | |
267 | dccp_encode_value_var(ndp, ptr, ndp_len); | |
268 | } | |
269 | } | |
270 | ||
271 | static inline int dccp_elapsed_time_len(const u32 elapsed_time) | |
272 | { | |
273 | return elapsed_time == 0 ? 0 : | |
274 | elapsed_time <= 0xFF ? 1 : | |
275 | elapsed_time <= 0xFFFF ? 2 : | |
276 | elapsed_time <= 0xFFFFFF ? 3 : 4; | |
277 | } | |
278 | ||
279 | void dccp_insert_option_elapsed_time(struct sock *sk, | |
280 | struct sk_buff *skb, | |
281 | u32 elapsed_time) | |
282 | { | |
283 | #ifdef DCCP_DEBUG | |
284 | struct dccp_sock *dp = dccp_sk(sk); | |
285 | const char *debug_prefix = dp->dccps_role == DCCP_ROLE_CLIENT ? "CLIENT TX opt: " : | |
286 | "server TX opt: "; | |
287 | #endif | |
288 | const int elapsed_time_len = dccp_elapsed_time_len(elapsed_time); | |
289 | const int len = 2 + elapsed_time_len; | |
290 | unsigned char *to; | |
291 | ||
292 | /* If elapsed_time == 0... */ | |
293 | if (elapsed_time_len == 2) | |
294 | return; | |
295 | ||
296 | if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN) { | |
297 | LIMIT_NETDEBUG(pr_info("DCCP: packet too small to insert elapsed time!\n")); | |
298 | return; | |
299 | } | |
300 | ||
301 | DCCP_SKB_CB(skb)->dccpd_opt_len += len; | |
302 | ||
303 | to = skb_push(skb, len); | |
304 | *to++ = DCCPO_ELAPSED_TIME; | |
305 | *to++ = len; | |
306 | ||
307 | dccp_encode_value_var(elapsed_time, to, elapsed_time_len); | |
308 | ||
309 | dccp_pr_debug("%sELAPSED_TIME=%u, len=%d, seqno=%llu\n", | |
310 | debug_prefix, elapsed_time, | |
311 | len, DCCP_SKB_CB(skb)->dccpd_seq); | |
312 | } | |
313 | ||
314 | EXPORT_SYMBOL(dccp_insert_option_elapsed_time); | |
315 | ||
316 | static void dccp_insert_option_ack_vector(struct sock *sk, struct sk_buff *skb) | |
317 | { | |
318 | struct dccp_sock *dp = dccp_sk(sk); | |
319 | #ifdef DCCP_DEBUG | |
320 | const char *debug_prefix = dp->dccps_role == DCCP_ROLE_CLIENT ? "CLIENT TX opt: " : | |
321 | "server TX opt: "; | |
322 | #endif | |
323 | struct dccp_ackpkts *ap = dp->dccps_hc_rx_ackpkts; | |
324 | int len = ap->dccpap_buf_vector_len + 2; | |
325 | const u32 elapsed_time = jiffies_to_usecs(jiffies - ap->dccpap_time) / 10; | |
326 | unsigned char *to, *from; | |
327 | ||
328 | if (elapsed_time != 0) | |
329 | dccp_insert_option_elapsed_time(sk, skb, elapsed_time); | |
330 | ||
331 | if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN) { | |
332 | LIMIT_NETDEBUG(pr_info("DCCP: packet too small to insert ACK Vector!\n")); | |
333 | return; | |
334 | } | |
335 | ||
336 | /* | |
337 | * XXX: now we have just one ack vector sent record, so | |
338 | * we have to wait for it to be cleared. | |
339 | * | |
340 | * Of course this is not acceptable, but this is just for | |
341 | * basic testing now. | |
342 | */ | |
343 | if (ap->dccpap_ack_seqno != DCCP_MAX_SEQNO + 1) | |
344 | return; | |
345 | ||
346 | DCCP_SKB_CB(skb)->dccpd_opt_len += len; | |
347 | ||
348 | to = skb_push(skb, len); | |
349 | *to++ = DCCPO_ACK_VECTOR_0; | |
350 | *to++ = len; | |
351 | ||
352 | len = ap->dccpap_buf_vector_len; | |
353 | from = ap->dccpap_buf + ap->dccpap_buf_head; | |
354 | ||
355 | /* Check if buf_head wraps */ | |
356 | if (ap->dccpap_buf_head + len > ap->dccpap_buf_len) { | |
357 | const unsigned int tailsize = ap->dccpap_buf_len - ap->dccpap_buf_head; | |
358 | ||
359 | memcpy(to, from, tailsize); | |
360 | to += tailsize; | |
361 | len -= tailsize; | |
362 | from = ap->dccpap_buf; | |
363 | } | |
364 | ||
365 | memcpy(to, from, len); | |
366 | /* | |
367 | * From draft-ietf-dccp-spec-11.txt: | |
368 | * | |
369 | * For each acknowledgement it sends, the HC-Receiver will add an | |
370 | * acknowledgement record. ack_seqno will equal the HC-Receiver | |
371 | * sequence number it used for the ack packet; ack_ptr will equal | |
372 | * buf_head; ack_ackno will equal buf_ackno; and ack_nonce will equal | |
373 | * buf_nonce. | |
374 | * | |
375 | * This implemention uses just one ack record for now. | |
376 | */ | |
377 | ap->dccpap_ack_seqno = DCCP_SKB_CB(skb)->dccpd_seq; | |
378 | ap->dccpap_ack_ptr = ap->dccpap_buf_head; | |
379 | ap->dccpap_ack_ackno = ap->dccpap_buf_ackno; | |
380 | ap->dccpap_ack_nonce = ap->dccpap_buf_nonce; | |
381 | ap->dccpap_ack_vector_len = ap->dccpap_buf_vector_len; | |
382 | ||
383 | dccp_pr_debug("%sACK Vector 0, len=%d, ack_seqno=%llu, ack_ackno=%llu\n", | |
384 | debug_prefix, ap->dccpap_ack_vector_len, | |
385 | ap->dccpap_ack_seqno, ap->dccpap_ack_ackno); | |
386 | } | |
387 | ||
388 | static inline void dccp_insert_option_timestamp(struct sock *sk, struct sk_buff *skb) | |
389 | { | |
390 | const u32 now = htonl(tcp_time_stamp); | |
391 | dccp_insert_option(sk, skb, DCCPO_TIMESTAMP, &now, sizeof(now)); | |
392 | } | |
393 | ||
394 | static void dccp_insert_option_timestamp_echo(struct sock *sk, struct sk_buff *skb) | |
395 | { | |
396 | struct dccp_sock *dp = dccp_sk(sk); | |
397 | #ifdef DCCP_DEBUG | |
398 | const char *debug_prefix = dp->dccps_role == DCCP_ROLE_CLIENT ? "CLIENT TX opt: " : | |
399 | "server TX opt: "; | |
400 | #endif | |
401 | u32 tstamp_echo; | |
402 | const u32 elapsed_time = jiffies_to_usecs(jiffies - dp->dccps_timestamp_time) / 10; | |
403 | const int elapsed_time_len = dccp_elapsed_time_len(elapsed_time); | |
404 | const int len = 6 + elapsed_time_len; | |
405 | unsigned char *to; | |
406 | ||
407 | if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN) { | |
408 | LIMIT_NETDEBUG(pr_info("DCCP: packet too small to insert timestamp echo!\n")); | |
409 | return; | |
410 | } | |
411 | ||
412 | DCCP_SKB_CB(skb)->dccpd_opt_len += len; | |
413 | ||
414 | to = skb_push(skb, len); | |
415 | *to++ = DCCPO_TIMESTAMP_ECHO; | |
416 | *to++ = len; | |
417 | ||
418 | tstamp_echo = htonl(dp->dccps_timestamp_echo); | |
419 | memcpy(to, &tstamp_echo, 4); | |
420 | to += 4; | |
421 | dccp_encode_value_var(elapsed_time, to, elapsed_time_len); | |
422 | ||
423 | dccp_pr_debug("%sTIMESTAMP_ECHO=%u, len=%d, seqno=%llu\n", | |
424 | debug_prefix, dp->dccps_timestamp_echo, | |
425 | len, DCCP_SKB_CB(skb)->dccpd_seq); | |
426 | ||
427 | dp->dccps_timestamp_echo = 0; | |
428 | dp->dccps_timestamp_time = 0; | |
429 | } | |
430 | ||
431 | void dccp_insert_options(struct sock *sk, struct sk_buff *skb) | |
432 | { | |
433 | struct dccp_sock *dp = dccp_sk(sk); | |
434 | ||
435 | DCCP_SKB_CB(skb)->dccpd_opt_len = 0; | |
436 | ||
437 | if (dp->dccps_options.dccpo_send_ndp_count) | |
438 | dccp_insert_option_ndp(sk, skb); | |
439 | ||
440 | if (!dccp_packet_without_ack(skb)) { | |
441 | if (dp->dccps_options.dccpo_send_ack_vector && | |
442 | dp->dccps_hc_rx_ackpkts->dccpap_buf_ackno != DCCP_MAX_SEQNO + 1) | |
443 | dccp_insert_option_ack_vector(sk, skb); | |
444 | ||
445 | dccp_insert_option_timestamp(sk, skb); | |
446 | if (dp->dccps_timestamp_echo != 0) | |
447 | dccp_insert_option_timestamp_echo(sk, skb); | |
448 | } | |
449 | ||
450 | ccid_hc_rx_insert_options(dp->dccps_hc_rx_ccid, sk, skb); | |
451 | ccid_hc_tx_insert_options(dp->dccps_hc_tx_ccid, sk, skb); | |
452 | ||
453 | /* XXX: insert other options when appropriate */ | |
454 | ||
455 | if (DCCP_SKB_CB(skb)->dccpd_opt_len != 0) { | |
456 | /* The length of all options has to be a multiple of 4 */ | |
457 | int padding = DCCP_SKB_CB(skb)->dccpd_opt_len % 4; | |
458 | ||
459 | if (padding != 0) { | |
460 | padding = 4 - padding; | |
461 | memset(skb_push(skb, padding), 0, padding); | |
462 | DCCP_SKB_CB(skb)->dccpd_opt_len += padding; | |
463 | } | |
464 | } | |
465 | } | |
466 | ||
467 | struct dccp_ackpkts *dccp_ackpkts_alloc(unsigned int len, int priority) | |
468 | { | |
469 | struct dccp_ackpkts *ap = kmalloc(sizeof(*ap) + len, priority); | |
470 | ||
471 | if (ap != NULL) { | |
472 | #ifdef DCCP_DEBUG | |
473 | memset(ap->dccpap_buf, 0xFF, len); | |
474 | #endif | |
475 | ap->dccpap_buf_len = len; | |
476 | ap->dccpap_buf_head = ap->dccpap_buf_tail = ap->dccpap_buf_len - 1; | |
477 | ap->dccpap_buf_ackno = ap->dccpap_ack_ackno = ap->dccpap_ack_seqno = DCCP_MAX_SEQNO + 1; | |
478 | ap->dccpap_buf_nonce = ap->dccpap_buf_nonce = 0; | |
479 | ap->dccpap_ack_ptr = 0; | |
480 | ap->dccpap_time = 0; | |
481 | ap->dccpap_buf_vector_len = ap->dccpap_ack_vector_len = 0; | |
482 | } | |
483 | ||
484 | return ap; | |
485 | } | |
486 | ||
487 | void dccp_ackpkts_free(struct dccp_ackpkts *ap) | |
488 | { | |
489 | if (ap != NULL) { | |
490 | #ifdef DCCP_DEBUG | |
491 | memset(ap, 0xFF, sizeof(*ap) + ap->dccpap_buf_len); | |
492 | #endif | |
493 | kfree(ap); | |
494 | } | |
495 | } | |
496 | ||
497 | static inline u8 dccp_ackpkts_state(const struct dccp_ackpkts *ap, | |
498 | const unsigned int index) | |
499 | { | |
500 | return ap->dccpap_buf[index] & DCCP_ACKPKTS_STATE_MASK; | |
501 | } | |
502 | ||
503 | static inline u8 dccp_ackpkts_len(const struct dccp_ackpkts *ap, | |
504 | const unsigned int index) | |
505 | { | |
506 | return ap->dccpap_buf[index] & DCCP_ACKPKTS_LEN_MASK; | |
507 | } | |
508 | ||
509 | /* | |
510 | * If several packets are missing, the HC-Receiver may prefer to enter multiple | |
511 | * bytes with run length 0, rather than a single byte with a larger run length; | |
512 | * this simplifies table updates if one of the missing packets arrives. | |
513 | */ | |
514 | static inline int dccp_ackpkts_set_buf_head_state(struct dccp_ackpkts *ap, | |
515 | const unsigned int packets, | |
516 | const unsigned char state) | |
517 | { | |
518 | unsigned int gap; | |
519 | signed long new_head; | |
520 | ||
521 | if (ap->dccpap_buf_vector_len + packets > ap->dccpap_buf_len) | |
522 | return -ENOBUFS; | |
523 | ||
524 | gap = packets - 1; | |
525 | new_head = ap->dccpap_buf_head - packets; | |
526 | ||
527 | if (new_head < 0) { | |
528 | if (gap > 0) { | |
529 | memset(ap->dccpap_buf, DCCP_ACKPKTS_STATE_NOT_RECEIVED, | |
530 | gap + new_head + 1); | |
531 | gap = -new_head; | |
532 | } | |
533 | new_head += ap->dccpap_buf_len; | |
534 | } | |
535 | ||
536 | ap->dccpap_buf_head = new_head; | |
537 | ||
538 | if (gap > 0) | |
539 | memset(ap->dccpap_buf + ap->dccpap_buf_head + 1, | |
540 | DCCP_ACKPKTS_STATE_NOT_RECEIVED, gap); | |
541 | ||
542 | ap->dccpap_buf[ap->dccpap_buf_head] = state; | |
543 | ap->dccpap_buf_vector_len += packets; | |
544 | return 0; | |
545 | } | |
546 | ||
547 | /* | |
548 | * Implements the draft-ietf-dccp-spec-11.txt Appendix A | |
549 | */ | |
550 | int dccp_ackpkts_add(struct dccp_ackpkts *ap, u64 ackno, u8 state) | |
551 | { | |
552 | /* | |
553 | * Check at the right places if the buffer is full, if it is, tell the | |
554 | * caller to start dropping packets till the HC-Sender acks our ACK | |
555 | * vectors, when we will free up space in dccpap_buf. | |
556 | * | |
557 | * We may well decide to do buffer compression, etc, but for now lets | |
558 | * just drop. | |
559 | * | |
560 | * From Appendix A: | |
561 | * | |
562 | * Of course, the circular buffer may overflow, either when the HC- | |
563 | * Sender is sending data at a very high rate, when the HC-Receiver's | |
564 | * acknowledgements are not reaching the HC-Sender, or when the HC- | |
565 | * Sender is forgetting to acknowledge those acks (so the HC-Receiver | |
566 | * is unable to clean up old state). In this case, the HC-Receiver | |
567 | * should either compress the buffer (by increasing run lengths when | |
568 | * possible), transfer its state to a larger buffer, or, as a last | |
569 | * resort, drop all received packets, without processing them | |
570 | * whatsoever, until its buffer shrinks again. | |
571 | */ | |
572 | ||
573 | /* See if this is the first ackno being inserted */ | |
574 | if (ap->dccpap_buf_vector_len == 0) { | |
575 | ap->dccpap_buf[ap->dccpap_buf_head] = state; | |
576 | ap->dccpap_buf_vector_len = 1; | |
577 | } else if (after48(ackno, ap->dccpap_buf_ackno)) { | |
578 | const u64 delta = dccp_delta_seqno(ap->dccpap_buf_ackno, ackno); | |
579 | ||
580 | /* | |
581 | * Look if the state of this packet is the same as the previous ackno | |
582 | * and if so if we can bump the head len. | |
583 | */ | |
584 | if (delta == 1 && | |
585 | dccp_ackpkts_state(ap, ap->dccpap_buf_head) == state && | |
586 | dccp_ackpkts_len(ap, ap->dccpap_buf_head) < DCCP_ACKPKTS_LEN_MASK) | |
587 | ap->dccpap_buf[ap->dccpap_buf_head]++; | |
588 | else if (dccp_ackpkts_set_buf_head_state(ap, delta, state)) | |
589 | return -ENOBUFS; | |
590 | } else { | |
591 | /* | |
592 | * A.1.2. Old Packets | |
593 | * | |
594 | * When a packet with Sequence Number S arrives, and S <= buf_ackno, | |
595 | * the HC-Receiver will scan the table for the byte corresponding to S. | |
596 | * (Indexing structures could reduce the complexity of this scan.) | |
597 | */ | |
598 | u64 delta = dccp_delta_seqno(ackno, ap->dccpap_buf_ackno); | |
599 | unsigned int index = ap->dccpap_buf_head; | |
600 | ||
601 | while (1) { | |
602 | const u8 len = dccp_ackpkts_len(ap, index); | |
603 | const u8 state = dccp_ackpkts_state(ap, index); | |
604 | /* | |
605 | * valid packets not yet in dccpap_buf have a reserved entry, with | |
606 | * a len equal to 0 | |
607 | */ | |
608 | if (state == DCCP_ACKPKTS_STATE_NOT_RECEIVED && | |
609 | len == 0 && delta == 0) { /* Found our reserved seat! */ | |
610 | dccp_pr_debug("Found %llu reserved seat!\n", ackno); | |
611 | ap->dccpap_buf[index] = state; | |
612 | goto out; | |
613 | } | |
614 | /* len == 0 means one packet */ | |
615 | if (delta < len + 1) | |
616 | goto out_duplicate; | |
617 | ||
618 | delta -= len + 1; | |
619 | if (++index == ap->dccpap_buf_len) | |
620 | index = 0; | |
621 | } | |
622 | } | |
623 | ||
624 | ap->dccpap_buf_ackno = ackno; | |
625 | ap->dccpap_time = jiffies; | |
626 | out: | |
627 | dccp_pr_debug(""); | |
628 | dccp_ackpkts_print(ap); | |
629 | return 0; | |
630 | ||
631 | out_duplicate: | |
632 | /* Duplicate packet */ | |
633 | dccp_pr_debug("Received a dup or already considered lost packet: %llu\n", ackno); | |
634 | return -EILSEQ; | |
635 | } | |
636 | ||
637 | #ifdef DCCP_DEBUG | |
638 | void dccp_ackvector_print(const u64 ackno, const unsigned char *vector, int len) | |
639 | { | |
640 | if (!dccp_debug) | |
641 | return; | |
642 | ||
643 | printk("ACK vector len=%d, ackno=%llu |", len, ackno); | |
644 | ||
645 | while (len--) { | |
646 | const u8 state = (*vector & DCCP_ACKPKTS_STATE_MASK) >> 6; | |
647 | const u8 rl = (*vector & DCCP_ACKPKTS_LEN_MASK); | |
648 | ||
649 | printk("%d,%d|", state, rl); | |
650 | ++vector; | |
651 | } | |
652 | ||
653 | printk("\n"); | |
654 | } | |
655 | ||
656 | void dccp_ackpkts_print(const struct dccp_ackpkts *ap) | |
657 | { | |
658 | dccp_ackvector_print(ap->dccpap_buf_ackno, | |
659 | ap->dccpap_buf + ap->dccpap_buf_head, | |
660 | ap->dccpap_buf_vector_len); | |
661 | } | |
662 | #endif | |
663 | ||
664 | static void dccp_ackpkts_trow_away_ack_record(struct dccp_ackpkts *ap) | |
665 | { | |
666 | /* | |
667 | * As we're keeping track of the ack vector size | |
668 | * (dccpap_buf_vector_len) and the sent ack vector size | |
669 | * (dccpap_ack_vector_len) we don't need dccpap_buf_tail at all, but | |
670 | * keep this code here as in the future we'll implement a vector of ack | |
671 | * records, as suggested in draft-ietf-dccp-spec-11.txt Appendix A. -acme | |
672 | */ | |
673 | #if 0 | |
674 | ap->dccpap_buf_tail = ap->dccpap_ack_ptr + 1; | |
675 | if (ap->dccpap_buf_tail >= ap->dccpap_buf_len) | |
676 | ap->dccpap_buf_tail -= ap->dccpap_buf_len; | |
677 | #endif | |
678 | ap->dccpap_buf_vector_len -= ap->dccpap_ack_vector_len; | |
679 | } | |
680 | ||
681 | void dccp_ackpkts_check_rcv_ackno(struct dccp_ackpkts *ap, struct sock *sk, | |
682 | u64 ackno) | |
683 | { | |
684 | /* Check if we actually sent an ACK vector */ | |
685 | if (ap->dccpap_ack_seqno == DCCP_MAX_SEQNO + 1) | |
686 | return; | |
687 | ||
688 | if (ackno == ap->dccpap_ack_seqno) { | |
689 | #ifdef DCCP_DEBUG | |
690 | struct dccp_sock *dp = dccp_sk(sk); | |
691 | const char *debug_prefix = dp->dccps_role == DCCP_ROLE_CLIENT ? "CLIENT rx ack: " : | |
692 | "server rx ack: "; | |
693 | #endif | |
694 | dccp_pr_debug("%sACK packet 0, len=%d, ack_seqno=%llu, ack_ackno=%llu, ACKED!\n", | |
695 | debug_prefix, 1, | |
696 | ap->dccpap_ack_seqno, ap->dccpap_ack_ackno); | |
697 | dccp_ackpkts_trow_away_ack_record(ap); | |
698 | ap->dccpap_ack_seqno = DCCP_MAX_SEQNO + 1; | |
699 | } | |
700 | } | |
701 | ||
702 | static void dccp_ackpkts_check_rcv_ackvector(struct dccp_ackpkts *ap, | |
703 | struct sock *sk, u64 ackno, | |
704 | const unsigned char len, | |
705 | const unsigned char *vector) | |
706 | { | |
707 | unsigned char i; | |
708 | ||
709 | /* Check if we actually sent an ACK vector */ | |
710 | if (ap->dccpap_ack_seqno == DCCP_MAX_SEQNO + 1) | |
711 | return; | |
712 | /* | |
713 | * We're in the receiver half connection, so if the received an ACK vector | |
714 | * ackno (e.g. 50) before dccpap_ack_seqno (e.g. 52), we're not interested. | |
715 | * | |
716 | * Extra explanation with example: | |
717 | * | |
718 | * if we received an ACK vector with ackno 50, it can only be acking | |
719 | * 50, 49, 48, etc, not 52 (the seqno for the ACK vector we sent). | |
720 | */ | |
721 | // dccp_pr_debug("is %llu < %llu? ", ackno, ap->dccpap_ack_seqno); | |
722 | if (before48(ackno, ap->dccpap_ack_seqno)) { | |
723 | // dccp_pr_debug_cat("yes\n"); | |
724 | return; | |
725 | } | |
726 | // dccp_pr_debug_cat("no\n"); | |
727 | ||
728 | i = len; | |
729 | while (i--) { | |
730 | const u8 rl = (*vector & DCCP_ACKPKTS_LEN_MASK); | |
731 | u64 ackno_end_rl; | |
732 | ||
733 | dccp_set_seqno(&ackno_end_rl, ackno - rl); | |
734 | ||
735 | // dccp_pr_debug("is %llu <= %llu <= %llu? ", ackno_end_rl, ap->dccpap_ack_seqno, ackno); | |
736 | if (between48(ap->dccpap_ack_seqno, ackno_end_rl, ackno)) { | |
737 | const u8 state = (*vector & DCCP_ACKPKTS_STATE_MASK) >> 6; | |
738 | // dccp_pr_debug_cat("yes\n"); | |
739 | ||
740 | if (state != DCCP_ACKPKTS_STATE_NOT_RECEIVED) { | |
741 | #ifdef DCCP_DEBUG | |
742 | struct dccp_sock *dp = dccp_sk(sk); | |
743 | const char *debug_prefix = dp->dccps_role == DCCP_ROLE_CLIENT ? "CLIENT rx ack: " : | |
744 | "server rx ack: "; | |
745 | #endif | |
746 | dccp_pr_debug("%sACK vector 0, len=%d, ack_seqno=%llu, ack_ackno=%llu, ACKED!\n", | |
747 | debug_prefix, len, | |
748 | ap->dccpap_ack_seqno, ap->dccpap_ack_ackno); | |
749 | dccp_ackpkts_trow_away_ack_record(ap); | |
750 | } | |
751 | /* | |
752 | * If dccpap_ack_seqno was not received, no problem we'll | |
753 | * send another ACK vector. | |
754 | */ | |
755 | ap->dccpap_ack_seqno = DCCP_MAX_SEQNO + 1; | |
756 | break; | |
757 | } | |
758 | // dccp_pr_debug_cat("no\n"); | |
759 | ||
760 | dccp_set_seqno(&ackno, ackno_end_rl - 1); | |
761 | ++vector; | |
762 | } | |
763 | } |