]>
Commit | Line | Data |
---|---|---|
ae31c339 ACM |
1 | /* |
2 | * net/dccp/ackvec.c | |
3 | * | |
4 | * An implementation of the DCCP protocol | |
5 | * Copyright (c) 2005 Arnaldo Carvalho de Melo <acme@ghostprotocols.net> | |
6 | * | |
7 | * This program is free software; you can redistribute it and/or modify it | |
8 | * under the terms of the GNU General Public License as published by the | |
9 | * Free Software Foundation; version 2 of the License; | |
10 | */ | |
11 | ||
12 | #include "ackvec.h" | |
13 | #include "dccp.h" | |
14 | ||
15 | #include <linux/dccp.h> | |
16 | #include <linux/skbuff.h> | |
17 | ||
18 | #include <net/sock.h> | |
19 | ||
20 | int dccp_insert_option_ackvec(struct sock *sk, struct sk_buff *skb) | |
21 | { | |
22 | struct dccp_sock *dp = dccp_sk(sk); | |
23 | struct dccp_ackvec *av = dp->dccps_hc_rx_ackvec; | |
24 | int len = av->dccpav_vec_len + 2; | |
25 | struct timeval now; | |
26 | u32 elapsed_time; | |
27 | unsigned char *to, *from; | |
28 | ||
29 | dccp_timestamp(sk, &now); | |
30 | elapsed_time = timeval_delta(&now, &av->dccpav_time) / 10; | |
31 | ||
32 | if (elapsed_time != 0) | |
33 | dccp_insert_option_elapsed_time(sk, skb, elapsed_time); | |
34 | ||
35 | if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN) | |
36 | return -1; | |
37 | ||
38 | /* | |
39 | * XXX: now we have just one ack vector sent record, so | |
40 | * we have to wait for it to be cleared. | |
41 | * | |
42 | * Of course this is not acceptable, but this is just for | |
43 | * basic testing now. | |
44 | */ | |
45 | if (av->dccpav_ack_seqno != DCCP_MAX_SEQNO + 1) | |
46 | return -1; | |
47 | ||
48 | DCCP_SKB_CB(skb)->dccpd_opt_len += len; | |
49 | ||
50 | to = skb_push(skb, len); | |
51 | *to++ = DCCPO_ACK_VECTOR_0; | |
52 | *to++ = len; | |
53 | ||
54 | len = av->dccpav_vec_len; | |
55 | from = av->dccpav_buf + av->dccpav_buf_head; | |
56 | ||
57 | /* Check if buf_head wraps */ | |
58 | if (av->dccpav_buf_head + len > av->dccpav_vec_len) { | |
59 | const u32 tailsize = (av->dccpav_vec_len - av->dccpav_buf_head); | |
60 | ||
61 | memcpy(to, from, tailsize); | |
62 | to += tailsize; | |
63 | len -= tailsize; | |
64 | from = av->dccpav_buf; | |
65 | } | |
66 | ||
67 | memcpy(to, from, len); | |
68 | /* | |
69 | * From draft-ietf-dccp-spec-11.txt: | |
70 | * | |
71 | * For each acknowledgement it sends, the HC-Receiver will add an | |
72 | * acknowledgement record. ack_seqno will equal the HC-Receiver | |
73 | * sequence number it used for the ack packet; ack_ptr will equal | |
74 | * buf_head; ack_ackno will equal buf_ackno; and ack_nonce will | |
75 | * equal buf_nonce. | |
76 | * | |
77 | * This implemention uses just one ack record for now. | |
78 | */ | |
79 | av->dccpav_ack_seqno = DCCP_SKB_CB(skb)->dccpd_seq; | |
80 | av->dccpav_ack_ptr = av->dccpav_buf_head; | |
81 | av->dccpav_ack_ackno = av->dccpav_buf_ackno; | |
82 | av->dccpav_ack_nonce = av->dccpav_buf_nonce; | |
83 | av->dccpav_sent_len = av->dccpav_vec_len; | |
84 | ||
85 | dccp_pr_debug("%sACK Vector 0, len=%d, ack_seqno=%llu, " | |
86 | "ack_ackno=%llu\n", | |
87 | debug_prefix, av->dccpav_sent_len, | |
88 | (unsigned long long)av->dccpav_ack_seqno, | |
89 | (unsigned long long)av->dccpav_ack_ackno); | |
90 | return -1; | |
91 | } | |
92 | ||
93 | struct dccp_ackvec *dccp_ackvec_alloc(const unsigned int len, | |
dd0fc66f | 94 | const gfp_t priority) |
ae31c339 ACM |
95 | { |
96 | struct dccp_ackvec *av = kmalloc(sizeof(*av) + len, priority); | |
97 | ||
98 | if (av != NULL) { | |
99 | av->dccpav_buf_len = len; | |
100 | av->dccpav_buf_head = | |
101 | av->dccpav_buf_tail = av->dccpav_buf_len - 1; | |
102 | av->dccpav_buf_ackno = | |
103 | av->dccpav_ack_ackno = av->dccpav_ack_seqno = ~0LLU; | |
104 | av->dccpav_buf_nonce = av->dccpav_buf_nonce = 0; | |
105 | av->dccpav_ack_ptr = 0; | |
106 | av->dccpav_time.tv_sec = 0; | |
107 | av->dccpav_time.tv_usec = 0; | |
108 | av->dccpav_sent_len = av->dccpav_vec_len = 0; | |
109 | } | |
110 | ||
111 | return av; | |
112 | } | |
113 | ||
114 | void dccp_ackvec_free(struct dccp_ackvec *av) | |
115 | { | |
116 | kfree(av); | |
117 | } | |
118 | ||
119 | static inline u8 dccp_ackvec_state(const struct dccp_ackvec *av, | |
120 | const unsigned int index) | |
121 | { | |
122 | return av->dccpav_buf[index] & DCCP_ACKVEC_STATE_MASK; | |
123 | } | |
124 | ||
125 | static inline u8 dccp_ackvec_len(const struct dccp_ackvec *av, | |
126 | const unsigned int index) | |
127 | { | |
128 | return av->dccpav_buf[index] & DCCP_ACKVEC_LEN_MASK; | |
129 | } | |
130 | ||
131 | /* | |
132 | * If several packets are missing, the HC-Receiver may prefer to enter multiple | |
133 | * bytes with run length 0, rather than a single byte with a larger run length; | |
134 | * this simplifies table updates if one of the missing packets arrives. | |
135 | */ | |
136 | static inline int dccp_ackvec_set_buf_head_state(struct dccp_ackvec *av, | |
137 | const unsigned int packets, | |
138 | const unsigned char state) | |
139 | { | |
140 | unsigned int gap; | |
141 | signed long new_head; | |
142 | ||
143 | if (av->dccpav_vec_len + packets > av->dccpav_buf_len) | |
144 | return -ENOBUFS; | |
145 | ||
146 | gap = packets - 1; | |
147 | new_head = av->dccpav_buf_head - packets; | |
148 | ||
149 | if (new_head < 0) { | |
150 | if (gap > 0) { | |
151 | memset(av->dccpav_buf, DCCP_ACKVEC_STATE_NOT_RECEIVED, | |
152 | gap + new_head + 1); | |
153 | gap = -new_head; | |
154 | } | |
155 | new_head += av->dccpav_buf_len; | |
156 | } | |
157 | ||
158 | av->dccpav_buf_head = new_head; | |
159 | ||
160 | if (gap > 0) | |
161 | memset(av->dccpav_buf + av->dccpav_buf_head + 1, | |
162 | DCCP_ACKVEC_STATE_NOT_RECEIVED, gap); | |
163 | ||
164 | av->dccpav_buf[av->dccpav_buf_head] = state; | |
165 | av->dccpav_vec_len += packets; | |
166 | return 0; | |
167 | } | |
168 | ||
169 | /* | |
170 | * Implements the draft-ietf-dccp-spec-11.txt Appendix A | |
171 | */ | |
172 | int dccp_ackvec_add(struct dccp_ackvec *av, const struct sock *sk, | |
173 | const u64 ackno, const u8 state) | |
174 | { | |
175 | /* | |
176 | * Check at the right places if the buffer is full, if it is, tell the | |
177 | * caller to start dropping packets till the HC-Sender acks our ACK | |
178 | * vectors, when we will free up space in dccpav_buf. | |
179 | * | |
180 | * We may well decide to do buffer compression, etc, but for now lets | |
181 | * just drop. | |
182 | * | |
183 | * From Appendix A: | |
184 | * | |
185 | * Of course, the circular buffer may overflow, either when the | |
186 | * HC-Sender is sending data at a very high rate, when the | |
187 | * HC-Receiver's acknowledgements are not reaching the HC-Sender, | |
188 | * or when the HC-Sender is forgetting to acknowledge those acks | |
189 | * (so the HC-Receiver is unable to clean up old state). In this | |
190 | * case, the HC-Receiver should either compress the buffer (by | |
191 | * increasing run lengths when possible), transfer its state to | |
192 | * a larger buffer, or, as a last resort, drop all received | |
193 | * packets, without processing them whatsoever, until its buffer | |
194 | * shrinks again. | |
195 | */ | |
196 | ||
197 | /* See if this is the first ackno being inserted */ | |
198 | if (av->dccpav_vec_len == 0) { | |
199 | av->dccpav_buf[av->dccpav_buf_head] = state; | |
200 | av->dccpav_vec_len = 1; | |
201 | } else if (after48(ackno, av->dccpav_buf_ackno)) { | |
202 | const u64 delta = dccp_delta_seqno(av->dccpav_buf_ackno, | |
203 | ackno); | |
204 | ||
205 | /* | |
206 | * Look if the state of this packet is the same as the | |
207 | * previous ackno and if so if we can bump the head len. | |
208 | */ | |
209 | if (delta == 1 && | |
210 | dccp_ackvec_state(av, av->dccpav_buf_head) == state && | |
211 | (dccp_ackvec_len(av, av->dccpav_buf_head) < | |
212 | DCCP_ACKVEC_LEN_MASK)) | |
213 | av->dccpav_buf[av->dccpav_buf_head]++; | |
214 | else if (dccp_ackvec_set_buf_head_state(av, delta, state)) | |
215 | return -ENOBUFS; | |
216 | } else { | |
217 | /* | |
218 | * A.1.2. Old Packets | |
219 | * | |
220 | * When a packet with Sequence Number S arrives, and | |
221 | * S <= buf_ackno, the HC-Receiver will scan the table | |
222 | * for the byte corresponding to S. (Indexing structures | |
223 | * could reduce the complexity of this scan.) | |
224 | */ | |
225 | u64 delta = dccp_delta_seqno(ackno, av->dccpav_buf_ackno); | |
226 | unsigned int index = av->dccpav_buf_head; | |
227 | ||
228 | while (1) { | |
229 | const u8 len = dccp_ackvec_len(av, index); | |
230 | const u8 state = dccp_ackvec_state(av, index); | |
231 | /* | |
232 | * valid packets not yet in dccpav_buf have a reserved | |
233 | * entry, with a len equal to 0. | |
234 | */ | |
235 | if (state == DCCP_ACKVEC_STATE_NOT_RECEIVED && | |
236 | len == 0 && delta == 0) { /* Found our | |
237 | reserved seat! */ | |
238 | dccp_pr_debug("Found %llu reserved seat!\n", | |
239 | (unsigned long long)ackno); | |
240 | av->dccpav_buf[index] = state; | |
241 | goto out; | |
242 | } | |
243 | /* len == 0 means one packet */ | |
244 | if (delta < len + 1) | |
245 | goto out_duplicate; | |
246 | ||
247 | delta -= len + 1; | |
248 | if (++index == av->dccpav_buf_len) | |
249 | index = 0; | |
250 | } | |
251 | } | |
252 | ||
253 | av->dccpav_buf_ackno = ackno; | |
254 | dccp_timestamp(sk, &av->dccpav_time); | |
255 | out: | |
256 | dccp_pr_debug(""); | |
257 | return 0; | |
258 | ||
259 | out_duplicate: | |
260 | /* Duplicate packet */ | |
261 | dccp_pr_debug("Received a dup or already considered lost " | |
262 | "packet: %llu\n", (unsigned long long)ackno); | |
263 | return -EILSEQ; | |
264 | } | |
265 | ||
266 | #ifdef CONFIG_IP_DCCP_DEBUG | |
267 | void dccp_ackvector_print(const u64 ackno, const unsigned char *vector, int len) | |
268 | { | |
269 | if (!dccp_debug) | |
270 | return; | |
271 | ||
272 | printk("ACK vector len=%d, ackno=%llu |", len, | |
273 | (unsigned long long)ackno); | |
274 | ||
275 | while (len--) { | |
276 | const u8 state = (*vector & DCCP_ACKVEC_STATE_MASK) >> 6; | |
277 | const u8 rl = *vector & DCCP_ACKVEC_LEN_MASK; | |
278 | ||
279 | printk("%d,%d|", state, rl); | |
280 | ++vector; | |
281 | } | |
282 | ||
283 | printk("\n"); | |
284 | } | |
285 | ||
286 | void dccp_ackvec_print(const struct dccp_ackvec *av) | |
287 | { | |
288 | dccp_ackvector_print(av->dccpav_buf_ackno, | |
289 | av->dccpav_buf + av->dccpav_buf_head, | |
290 | av->dccpav_vec_len); | |
291 | } | |
292 | #endif | |
293 | ||
294 | static void dccp_ackvec_trow_away_ack_record(struct dccp_ackvec *av) | |
295 | { | |
296 | /* | |
297 | * As we're keeping track of the ack vector size (dccpav_vec_len) and | |
298 | * the sent ack vector size (dccpav_sent_len) we don't need | |
299 | * dccpav_buf_tail at all, but keep this code here as in the future | |
300 | * we'll implement a vector of ack records, as suggested in | |
301 | * draft-ietf-dccp-spec-11.txt Appendix A. -acme | |
302 | */ | |
303 | #if 0 | |
304 | av->dccpav_buf_tail = av->dccpav_ack_ptr + 1; | |
305 | if (av->dccpav_buf_tail >= av->dccpav_vec_len) | |
306 | av->dccpav_buf_tail -= av->dccpav_vec_len; | |
307 | #endif | |
308 | av->dccpav_vec_len -= av->dccpav_sent_len; | |
309 | } | |
310 | ||
311 | void dccp_ackvec_check_rcv_ackno(struct dccp_ackvec *av, struct sock *sk, | |
312 | const u64 ackno) | |
313 | { | |
314 | /* Check if we actually sent an ACK vector */ | |
315 | if (av->dccpav_ack_seqno == DCCP_MAX_SEQNO + 1) | |
316 | return; | |
317 | ||
318 | if (ackno == av->dccpav_ack_seqno) { | |
319 | #ifdef CONFIG_IP_DCCP_DEBUG | |
320 | struct dccp_sock *dp = dccp_sk(sk); | |
321 | const char *debug_prefix = dp->dccps_role == DCCP_ROLE_CLIENT ? | |
322 | "CLIENT rx ack: " : "server rx ack: "; | |
323 | #endif | |
324 | dccp_pr_debug("%sACK packet 0, len=%d, ack_seqno=%llu, " | |
325 | "ack_ackno=%llu, ACKED!\n", | |
326 | debug_prefix, 1, | |
327 | (unsigned long long)av->dccpav_ack_seqno, | |
328 | (unsigned long long)av->dccpav_ack_ackno); | |
329 | dccp_ackvec_trow_away_ack_record(av); | |
330 | av->dccpav_ack_seqno = DCCP_MAX_SEQNO + 1; | |
331 | } | |
332 | } | |
333 | ||
334 | static void dccp_ackvec_check_rcv_ackvector(struct dccp_ackvec *av, | |
335 | struct sock *sk, u64 ackno, | |
336 | const unsigned char len, | |
337 | const unsigned char *vector) | |
338 | { | |
339 | unsigned char i; | |
340 | ||
341 | /* Check if we actually sent an ACK vector */ | |
342 | if (av->dccpav_ack_seqno == DCCP_MAX_SEQNO + 1) | |
343 | return; | |
344 | /* | |
345 | * We're in the receiver half connection, so if the received an ACK | |
346 | * vector ackno (e.g. 50) before dccpav_ack_seqno (e.g. 52), we're | |
347 | * not interested. | |
348 | * | |
349 | * Extra explanation with example: | |
350 | * | |
351 | * if we received an ACK vector with ackno 50, it can only be acking | |
352 | * 50, 49, 48, etc, not 52 (the seqno for the ACK vector we sent). | |
353 | */ | |
354 | /* dccp_pr_debug("is %llu < %llu? ", ackno, av->dccpav_ack_seqno); */ | |
355 | if (before48(ackno, av->dccpav_ack_seqno)) { | |
356 | /* dccp_pr_debug_cat("yes\n"); */ | |
357 | return; | |
358 | } | |
359 | /* dccp_pr_debug_cat("no\n"); */ | |
360 | ||
361 | i = len; | |
362 | while (i--) { | |
363 | const u8 rl = *vector & DCCP_ACKVEC_LEN_MASK; | |
364 | u64 ackno_end_rl; | |
365 | ||
366 | dccp_set_seqno(&ackno_end_rl, ackno - rl); | |
367 | ||
368 | /* | |
369 | * dccp_pr_debug("is %llu <= %llu <= %llu? ", ackno_end_rl, | |
370 | * av->dccpav_ack_seqno, ackno); | |
371 | */ | |
372 | if (between48(av->dccpav_ack_seqno, ackno_end_rl, ackno)) { | |
373 | const u8 state = (*vector & | |
374 | DCCP_ACKVEC_STATE_MASK) >> 6; | |
375 | /* dccp_pr_debug_cat("yes\n"); */ | |
376 | ||
377 | if (state != DCCP_ACKVEC_STATE_NOT_RECEIVED) { | |
378 | #ifdef CONFIG_IP_DCCP_DEBUG | |
379 | struct dccp_sock *dp = dccp_sk(sk); | |
380 | const char *debug_prefix = | |
381 | dp->dccps_role == DCCP_ROLE_CLIENT ? | |
382 | "CLIENT rx ack: " : "server rx ack: "; | |
383 | #endif | |
384 | dccp_pr_debug("%sACK vector 0, len=%d, " | |
385 | "ack_seqno=%llu, ack_ackno=%llu, " | |
386 | "ACKED!\n", | |
387 | debug_prefix, len, | |
388 | (unsigned long long) | |
389 | av->dccpav_ack_seqno, | |
390 | (unsigned long long) | |
391 | av->dccpav_ack_ackno); | |
392 | dccp_ackvec_trow_away_ack_record(av); | |
393 | } | |
394 | /* | |
395 | * If dccpav_ack_seqno was not received, no problem | |
396 | * we'll send another ACK vector. | |
397 | */ | |
398 | av->dccpav_ack_seqno = DCCP_MAX_SEQNO + 1; | |
399 | break; | |
400 | } | |
401 | /* dccp_pr_debug_cat("no\n"); */ | |
402 | ||
403 | dccp_set_seqno(&ackno, ackno_end_rl - 1); | |
404 | ++vector; | |
405 | } | |
406 | } | |
407 | ||
408 | int dccp_ackvec_parse(struct sock *sk, const struct sk_buff *skb, | |
409 | const u8 opt, const u8 *value, const u8 len) | |
410 | { | |
411 | if (len > DCCP_MAX_ACKVEC_LEN) | |
412 | return -1; | |
413 | ||
414 | /* dccp_ackvector_print(DCCP_SKB_CB(skb)->dccpd_ack_seq, value, len); */ | |
415 | dccp_ackvec_check_rcv_ackvector(dccp_sk(sk)->dccps_hc_rx_ackvec, sk, | |
416 | DCCP_SKB_CB(skb)->dccpd_ack_seq, | |
417 | len, value); | |
418 | return 0; | |
419 | } |