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2a91aa39 AB |
1 | /* |
2 | * net/dccp/ccids/ccid2.c | |
3 | * | |
4 | * Copyright (c) 2005, 2006 Andrea Bittau <a.bittau@cs.ucl.ac.uk> | |
5 | * | |
6 | * Changes to meet Linux coding standards, and DCCP infrastructure fixes. | |
7 | * | |
8 | * Copyright (c) 2006 Arnaldo Carvalho de Melo <acme@conectiva.com.br> | |
9 | * | |
10 | * This program is free software; you can redistribute it and/or modify | |
11 | * it under the terms of the GNU General Public License as published by | |
12 | * the Free Software Foundation; either version 2 of the License, or | |
13 | * (at your option) any later version. | |
14 | * | |
15 | * This program is distributed in the hope that it will be useful, | |
16 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
17 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
18 | * GNU General Public License for more details. | |
19 | * | |
20 | * You should have received a copy of the GNU General Public License | |
21 | * along with this program; if not, write to the Free Software | |
22 | * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. | |
23 | */ | |
24 | ||
25 | /* | |
0e64e94e | 26 | * This implementation should follow RFC 4341 |
2a91aa39 AB |
27 | */ |
28 | ||
2a91aa39 AB |
29 | #include "../ccid.h" |
30 | #include "../dccp.h" | |
31 | #include "ccid2.h" | |
32 | ||
2a91aa39 | 33 | |
8d424f6c | 34 | #ifdef CONFIG_IP_DCCP_CCID2_DEBUG |
84116716 GR |
35 | static int ccid2_debug; |
36 | #define ccid2_pr_debug(format, a...) DCCP_PR_DEBUG(ccid2_debug, format, ##a) | |
2a91aa39 | 37 | |
2a91aa39 AB |
38 | static void ccid2_hc_tx_check_sanity(const struct ccid2_hc_tx_sock *hctx) |
39 | { | |
40 | int len = 0; | |
2a91aa39 | 41 | int pipe = 0; |
c0c736db | 42 | struct ccid2_seq *seqp = hctx->ccid2hctx_seqh; |
2a91aa39 AB |
43 | |
44 | /* there is data in the chain */ | |
45 | if (seqp != hctx->ccid2hctx_seqt) { | |
46 | seqp = seqp->ccid2s_prev; | |
47 | len++; | |
48 | if (!seqp->ccid2s_acked) | |
49 | pipe++; | |
50 | ||
51 | while (seqp != hctx->ccid2hctx_seqt) { | |
c0c736db | 52 | struct ccid2_seq *prev = seqp->ccid2s_prev; |
2a91aa39 | 53 | |
2a91aa39 AB |
54 | len++; |
55 | if (!prev->ccid2s_acked) | |
56 | pipe++; | |
57 | ||
58 | /* packets are sent sequentially */ | |
5e28599a GR |
59 | BUG_ON(dccp_delta_seqno(seqp->ccid2s_seq, |
60 | prev->ccid2s_seq ) >= 0); | |
29651cda AB |
61 | BUG_ON(time_before(seqp->ccid2s_sent, |
62 | prev->ccid2s_sent)); | |
2a91aa39 AB |
63 | |
64 | seqp = prev; | |
65 | } | |
66 | } | |
67 | ||
68 | BUG_ON(pipe != hctx->ccid2hctx_pipe); | |
69 | ccid2_pr_debug("len of chain=%d\n", len); | |
70 | ||
71 | do { | |
72 | seqp = seqp->ccid2s_prev; | |
73 | len++; | |
c0c736db | 74 | } while (seqp != hctx->ccid2hctx_seqh); |
2a91aa39 | 75 | |
2a91aa39 | 76 | ccid2_pr_debug("total len=%d\n", len); |
07978aab | 77 | BUG_ON(len != hctx->ccid2hctx_seqbufc * CCID2_SEQBUF_LEN); |
2a91aa39 AB |
78 | } |
79 | #else | |
84116716 GR |
80 | #define ccid2_pr_debug(format, a...) |
81 | #define ccid2_hc_tx_check_sanity(hctx) | |
2a91aa39 AB |
82 | #endif |
83 | ||
cd1f7d34 | 84 | static int ccid2_hc_tx_alloc_seq(struct ccid2_hc_tx_sock *hctx) |
07978aab AB |
85 | { |
86 | struct ccid2_seq *seqp; | |
87 | int i; | |
88 | ||
89 | /* check if we have space to preserve the pointer to the buffer */ | |
90 | if (hctx->ccid2hctx_seqbufc >= (sizeof(hctx->ccid2hctx_seqbuf) / | |
91 | sizeof(struct ccid2_seq*))) | |
92 | return -ENOMEM; | |
93 | ||
94 | /* allocate buffer and initialize linked list */ | |
cd1f7d34 | 95 | seqp = kmalloc(CCID2_SEQBUF_LEN * sizeof(struct ccid2_seq), gfp_any()); |
07978aab AB |
96 | if (seqp == NULL) |
97 | return -ENOMEM; | |
98 | ||
cd1f7d34 | 99 | for (i = 0; i < (CCID2_SEQBUF_LEN - 1); i++) { |
07978aab AB |
100 | seqp[i].ccid2s_next = &seqp[i + 1]; |
101 | seqp[i + 1].ccid2s_prev = &seqp[i]; | |
102 | } | |
cd1f7d34 GR |
103 | seqp[CCID2_SEQBUF_LEN - 1].ccid2s_next = seqp; |
104 | seqp->ccid2s_prev = &seqp[CCID2_SEQBUF_LEN - 1]; | |
07978aab AB |
105 | |
106 | /* This is the first allocation. Initiate the head and tail. */ | |
107 | if (hctx->ccid2hctx_seqbufc == 0) | |
108 | hctx->ccid2hctx_seqh = hctx->ccid2hctx_seqt = seqp; | |
109 | else { | |
110 | /* link the existing list with the one we just created */ | |
111 | hctx->ccid2hctx_seqh->ccid2s_next = seqp; | |
112 | seqp->ccid2s_prev = hctx->ccid2hctx_seqh; | |
113 | ||
cd1f7d34 GR |
114 | hctx->ccid2hctx_seqt->ccid2s_prev = &seqp[CCID2_SEQBUF_LEN - 1]; |
115 | seqp[CCID2_SEQBUF_LEN - 1].ccid2s_next = hctx->ccid2hctx_seqt; | |
07978aab AB |
116 | } |
117 | ||
118 | /* store the original pointer to the buffer so we can free it */ | |
119 | hctx->ccid2hctx_seqbuf[hctx->ccid2hctx_seqbufc] = seqp; | |
120 | hctx->ccid2hctx_seqbufc++; | |
121 | ||
122 | return 0; | |
123 | } | |
124 | ||
6b57c93d | 125 | static int ccid2_hc_tx_send_packet(struct sock *sk, struct sk_buff *skb) |
2a91aa39 | 126 | { |
6c583248 | 127 | struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk); |
2a91aa39 | 128 | |
83399361 GR |
129 | if (hctx->ccid2hctx_pipe < hctx->ccid2hctx_cwnd) |
130 | return 0; | |
2a91aa39 | 131 | |
446dec30 | 132 | return 1; /* XXX CCID should dequeue when ready instead of polling */ |
2a91aa39 AB |
133 | } |
134 | ||
df054e1d | 135 | static void ccid2_change_l_ack_ratio(struct sock *sk, u32 val) |
2a91aa39 AB |
136 | { |
137 | struct dccp_sock *dp = dccp_sk(sk); | |
d50ad163 GR |
138 | u32 max_ratio = DIV_ROUND_UP(ccid2_hc_tx_sk(sk)->ccid2hctx_cwnd, 2); |
139 | ||
2a91aa39 | 140 | /* |
d50ad163 GR |
141 | * Ensure that Ack Ratio does not exceed ceil(cwnd/2), which is (2) from |
142 | * RFC 4341, 6.1.2. We ignore the statement that Ack Ratio 2 is always | |
143 | * acceptable since this causes starvation/deadlock whenever cwnd < 2. | |
144 | * The same problem arises when Ack Ratio is 0 (ie. Ack Ratio disabled). | |
2a91aa39 | 145 | */ |
d50ad163 GR |
146 | if (val == 0 || val > max_ratio) { |
147 | DCCP_WARN("Limiting Ack Ratio (%u) to %u\n", val, max_ratio); | |
148 | val = max_ratio; | |
2a91aa39 | 149 | } |
df054e1d GR |
150 | if (val > 0xFFFF) /* RFC 4340, 11.3 */ |
151 | val = 0xFFFF; | |
2a91aa39 | 152 | |
d50ad163 GR |
153 | if (val == dp->dccps_l_ack_ratio) |
154 | return; | |
155 | ||
df054e1d | 156 | ccid2_pr_debug("changing local ack ratio to %u\n", val); |
2a91aa39 AB |
157 | dp->dccps_l_ack_ratio = val; |
158 | } | |
159 | ||
593f16aa AB |
160 | static void ccid2_change_srtt(struct ccid2_hc_tx_sock *hctx, long val) |
161 | { | |
162 | ccid2_pr_debug("change SRTT to %ld\n", val); | |
163 | hctx->ccid2hctx_srtt = val; | |
164 | } | |
165 | ||
2a91aa39 AB |
166 | static void ccid2_start_rto_timer(struct sock *sk); |
167 | ||
168 | static void ccid2_hc_tx_rto_expire(unsigned long data) | |
169 | { | |
170 | struct sock *sk = (struct sock *)data; | |
171 | struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk); | |
172 | long s; | |
173 | ||
2a91aa39 AB |
174 | bh_lock_sock(sk); |
175 | if (sock_owned_by_user(sk)) { | |
176 | sk_reset_timer(sk, &hctx->ccid2hctx_rtotimer, | |
177 | jiffies + HZ / 5); | |
178 | goto out; | |
179 | } | |
180 | ||
181 | ccid2_pr_debug("RTO_EXPIRE\n"); | |
182 | ||
183 | ccid2_hc_tx_check_sanity(hctx); | |
184 | ||
185 | /* back-off timer */ | |
186 | hctx->ccid2hctx_rto <<= 1; | |
187 | ||
188 | s = hctx->ccid2hctx_rto / HZ; | |
189 | if (s > 60) | |
190 | hctx->ccid2hctx_rto = 60 * HZ; | |
191 | ||
192 | ccid2_start_rto_timer(sk); | |
193 | ||
194 | /* adjust pipe, cwnd etc */ | |
3deeadd7 | 195 | hctx->ccid2hctx_ssthresh = hctx->ccid2hctx_cwnd / 2; |
2a91aa39 AB |
196 | if (hctx->ccid2hctx_ssthresh < 2) |
197 | hctx->ccid2hctx_ssthresh = 2; | |
3deeadd7 | 198 | hctx->ccid2hctx_cwnd = 1; |
95b21d7e | 199 | hctx->ccid2hctx_pipe = 0; |
2a91aa39 AB |
200 | |
201 | /* clear state about stuff we sent */ | |
202 | hctx->ccid2hctx_seqt = hctx->ccid2hctx_seqh; | |
203 | hctx->ccid2hctx_ssacks = 0; | |
204 | hctx->ccid2hctx_acks = 0; | |
2a91aa39 AB |
205 | |
206 | /* clear ack ratio state. */ | |
2a91aa39 AB |
207 | hctx->ccid2hctx_rpseq = 0; |
208 | hctx->ccid2hctx_rpdupack = -1; | |
209 | ccid2_change_l_ack_ratio(sk, 1); | |
210 | ccid2_hc_tx_check_sanity(hctx); | |
211 | out: | |
212 | bh_unlock_sock(sk); | |
77ff72d5 | 213 | sock_put(sk); |
2a91aa39 AB |
214 | } |
215 | ||
216 | static void ccid2_start_rto_timer(struct sock *sk) | |
217 | { | |
218 | struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk); | |
219 | ||
220 | ccid2_pr_debug("setting RTO timeout=%ld\n", hctx->ccid2hctx_rto); | |
221 | ||
222 | BUG_ON(timer_pending(&hctx->ccid2hctx_rtotimer)); | |
223 | sk_reset_timer(sk, &hctx->ccid2hctx_rtotimer, | |
224 | jiffies + hctx->ccid2hctx_rto); | |
225 | } | |
226 | ||
6b57c93d | 227 | static void ccid2_hc_tx_packet_sent(struct sock *sk, int more, unsigned int len) |
2a91aa39 AB |
228 | { |
229 | struct dccp_sock *dp = dccp_sk(sk); | |
230 | struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk); | |
07978aab | 231 | struct ccid2_seq *next; |
2a91aa39 AB |
232 | u64 seq; |
233 | ||
95b21d7e | 234 | hctx->ccid2hctx_pipe++; |
2a91aa39 AB |
235 | |
236 | /* There is an issue. What if another packet is sent between | |
237 | * packet_send() and packet_sent(). Then the sequence number would be | |
238 | * wrong. | |
239 | * -sorbo. | |
240 | */ | |
241 | seq = dp->dccps_gss; | |
242 | ||
243 | hctx->ccid2hctx_seqh->ccid2s_seq = seq; | |
244 | hctx->ccid2hctx_seqh->ccid2s_acked = 0; | |
245 | hctx->ccid2hctx_seqh->ccid2s_sent = jiffies; | |
2a91aa39 | 246 | |
07978aab AB |
247 | next = hctx->ccid2hctx_seqh->ccid2s_next; |
248 | /* check if we need to alloc more space */ | |
249 | if (next == hctx->ccid2hctx_seqt) { | |
7d9e8931 GR |
250 | if (ccid2_hc_tx_alloc_seq(hctx)) { |
251 | DCCP_CRIT("packet history - out of memory!"); | |
252 | /* FIXME: find a more graceful way to bail out */ | |
253 | return; | |
254 | } | |
07978aab AB |
255 | next = hctx->ccid2hctx_seqh->ccid2s_next; |
256 | BUG_ON(next == hctx->ccid2hctx_seqt); | |
2a91aa39 | 257 | } |
07978aab AB |
258 | hctx->ccid2hctx_seqh = next; |
259 | ||
260 | ccid2_pr_debug("cwnd=%d pipe=%d\n", hctx->ccid2hctx_cwnd, | |
261 | hctx->ccid2hctx_pipe); | |
2a91aa39 | 262 | |
900bfed4 GR |
263 | /* |
264 | * FIXME: The code below is broken and the variables have been removed | |
265 | * from the socket struct. The `ackloss' variable was always set to 0, | |
266 | * and with arsent there are several problems: | |
267 | * (i) it doesn't just count the number of Acks, but all sent packets; | |
268 | * (ii) it is expressed in # of packets, not # of windows, so the | |
269 | * comparison below uses the wrong formula: Appendix A of RFC 4341 | |
270 | * comes up with the number K = cwnd / (R^2 - R) of consecutive windows | |
271 | * of data with no lost or marked Ack packets. If arsent were the # of | |
272 | * consecutive Acks received without loss, then Ack Ratio needs to be | |
273 | * decreased by 1 when | |
274 | * arsent >= K * cwnd / R = cwnd^2 / (R^3 - R^2) | |
275 | * where cwnd / R is the number of Acks received per window of data | |
276 | * (cf. RFC 4341, App. A). The problems are that | |
277 | * - arsent counts other packets as well; | |
278 | * - the comparison uses a formula different from RFC 4341; | |
279 | * - computing a cubic/quadratic equation each time is too complicated. | |
280 | * Hence a different algorithm is needed. | |
281 | */ | |
282 | #if 0 | |
2a91aa39 AB |
283 | /* Ack Ratio. Need to maintain a concept of how many windows we sent */ |
284 | hctx->ccid2hctx_arsent++; | |
285 | /* We had an ack loss in this window... */ | |
286 | if (hctx->ccid2hctx_ackloss) { | |
287 | if (hctx->ccid2hctx_arsent >= hctx->ccid2hctx_cwnd) { | |
c0c736db ACM |
288 | hctx->ccid2hctx_arsent = 0; |
289 | hctx->ccid2hctx_ackloss = 0; | |
2a91aa39 | 290 | } |
c0c736db ACM |
291 | } else { |
292 | /* No acks lost up to now... */ | |
2a91aa39 AB |
293 | /* decrease ack ratio if enough packets were sent */ |
294 | if (dp->dccps_l_ack_ratio > 1) { | |
295 | /* XXX don't calculate denominator each time */ | |
c0c736db ACM |
296 | int denom = dp->dccps_l_ack_ratio * dp->dccps_l_ack_ratio - |
297 | dp->dccps_l_ack_ratio; | |
2a91aa39 | 298 | |
2a91aa39 AB |
299 | denom = hctx->ccid2hctx_cwnd * hctx->ccid2hctx_cwnd / denom; |
300 | ||
301 | if (hctx->ccid2hctx_arsent >= denom) { | |
302 | ccid2_change_l_ack_ratio(sk, dp->dccps_l_ack_ratio - 1); | |
303 | hctx->ccid2hctx_arsent = 0; | |
304 | } | |
c0c736db ACM |
305 | } else { |
306 | /* we can't increase ack ratio further [1] */ | |
2a91aa39 AB |
307 | hctx->ccid2hctx_arsent = 0; /* or maybe set it to cwnd*/ |
308 | } | |
309 | } | |
900bfed4 | 310 | #endif |
2a91aa39 AB |
311 | |
312 | /* setup RTO timer */ | |
c0c736db | 313 | if (!timer_pending(&hctx->ccid2hctx_rtotimer)) |
2a91aa39 | 314 | ccid2_start_rto_timer(sk); |
c0c736db | 315 | |
8d424f6c | 316 | #ifdef CONFIG_IP_DCCP_CCID2_DEBUG |
234af484 | 317 | ccid2_pr_debug("Sent: seq=%llu\n", (unsigned long long)seq); |
2a91aa39 AB |
318 | do { |
319 | struct ccid2_seq *seqp = hctx->ccid2hctx_seqt; | |
320 | ||
321 | while (seqp != hctx->ccid2hctx_seqh) { | |
322 | ccid2_pr_debug("out seq=%llu acked=%d time=%lu\n", | |
8109b02b | 323 | (unsigned long long)seqp->ccid2s_seq, |
234af484 | 324 | seqp->ccid2s_acked, seqp->ccid2s_sent); |
2a91aa39 AB |
325 | seqp = seqp->ccid2s_next; |
326 | } | |
c0c736db | 327 | } while (0); |
2a91aa39 AB |
328 | ccid2_pr_debug("=========\n"); |
329 | ccid2_hc_tx_check_sanity(hctx); | |
330 | #endif | |
331 | } | |
332 | ||
333 | /* XXX Lame code duplication! | |
334 | * returns -1 if none was found. | |
335 | * else returns the next offset to use in the function call. | |
336 | */ | |
337 | static int ccid2_ackvector(struct sock *sk, struct sk_buff *skb, int offset, | |
338 | unsigned char **vec, unsigned char *veclen) | |
339 | { | |
c9eaf173 YH |
340 | const struct dccp_hdr *dh = dccp_hdr(skb); |
341 | unsigned char *options = (unsigned char *)dh + dccp_hdr_len(skb); | |
342 | unsigned char *opt_ptr; | |
343 | const unsigned char *opt_end = (unsigned char *)dh + | |
344 | (dh->dccph_doff * 4); | |
345 | unsigned char opt, len; | |
346 | unsigned char *value; | |
2a91aa39 AB |
347 | |
348 | BUG_ON(offset < 0); | |
349 | options += offset; | |
350 | opt_ptr = options; | |
351 | if (opt_ptr >= opt_end) | |
352 | return -1; | |
353 | ||
354 | while (opt_ptr != opt_end) { | |
c9eaf173 YH |
355 | opt = *opt_ptr++; |
356 | len = 0; | |
357 | value = NULL; | |
358 | ||
359 | /* Check if this isn't a single byte option */ | |
360 | if (opt > DCCPO_MAX_RESERVED) { | |
361 | if (opt_ptr == opt_end) | |
362 | goto out_invalid_option; | |
363 | ||
364 | len = *opt_ptr++; | |
365 | if (len < 3) | |
366 | goto out_invalid_option; | |
367 | /* | |
368 | * Remove the type and len fields, leaving | |
369 | * just the value size | |
370 | */ | |
371 | len -= 2; | |
372 | value = opt_ptr; | |
373 | opt_ptr += len; | |
374 | ||
375 | if (opt_ptr > opt_end) | |
376 | goto out_invalid_option; | |
377 | } | |
2a91aa39 AB |
378 | |
379 | switch (opt) { | |
380 | case DCCPO_ACK_VECTOR_0: | |
381 | case DCCPO_ACK_VECTOR_1: | |
382 | *vec = value; | |
383 | *veclen = len; | |
384 | return offset + (opt_ptr - options); | |
2a91aa39 AB |
385 | } |
386 | } | |
387 | ||
388 | return -1; | |
389 | ||
390 | out_invalid_option: | |
59348b19 | 391 | DCCP_BUG("Invalid option - this should not happen (previous parsing)!"); |
2a91aa39 AB |
392 | return -1; |
393 | } | |
394 | ||
77ff72d5 | 395 | static void ccid2_hc_tx_kill_rto_timer(struct sock *sk) |
2a91aa39 | 396 | { |
77ff72d5 AB |
397 | struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk); |
398 | ||
399 | sk_stop_timer(sk, &hctx->ccid2hctx_rtotimer); | |
400 | ccid2_pr_debug("deleted RTO timer\n"); | |
2a91aa39 AB |
401 | } |
402 | ||
403 | static inline void ccid2_new_ack(struct sock *sk, | |
c9eaf173 | 404 | struct ccid2_seq *seqp, |
2a91aa39 AB |
405 | unsigned int *maxincr) |
406 | { | |
407 | struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk); | |
408 | ||
409 | /* slow start */ | |
410 | if (hctx->ccid2hctx_cwnd < hctx->ccid2hctx_ssthresh) { | |
411 | hctx->ccid2hctx_acks = 0; | |
412 | ||
413 | /* We can increase cwnd at most maxincr [ack_ratio/2] */ | |
414 | if (*maxincr) { | |
415 | /* increase every 2 acks */ | |
416 | hctx->ccid2hctx_ssacks++; | |
417 | if (hctx->ccid2hctx_ssacks == 2) { | |
3deeadd7 | 418 | hctx->ccid2hctx_cwnd++; |
2a91aa39 AB |
419 | hctx->ccid2hctx_ssacks = 0; |
420 | *maxincr = *maxincr - 1; | |
421 | } | |
c0c736db ACM |
422 | } else { |
423 | /* increased cwnd enough for this single ack */ | |
2a91aa39 AB |
424 | hctx->ccid2hctx_ssacks = 0; |
425 | } | |
c0c736db | 426 | } else { |
2a91aa39 AB |
427 | hctx->ccid2hctx_ssacks = 0; |
428 | hctx->ccid2hctx_acks++; | |
429 | ||
430 | if (hctx->ccid2hctx_acks >= hctx->ccid2hctx_cwnd) { | |
3deeadd7 | 431 | hctx->ccid2hctx_cwnd++; |
2a91aa39 AB |
432 | hctx->ccid2hctx_acks = 0; |
433 | } | |
434 | } | |
435 | ||
436 | /* update RTO */ | |
437 | if (hctx->ccid2hctx_srtt == -1 || | |
29651cda AB |
438 | time_after(jiffies, hctx->ccid2hctx_lastrtt + hctx->ccid2hctx_srtt)) { |
439 | unsigned long r = (long)jiffies - (long)seqp->ccid2s_sent; | |
2a91aa39 AB |
440 | int s; |
441 | ||
442 | /* first measurement */ | |
443 | if (hctx->ccid2hctx_srtt == -1) { | |
444 | ccid2_pr_debug("R: %lu Time=%lu seq=%llu\n", | |
8109b02b | 445 | r, jiffies, |
234af484 | 446 | (unsigned long long)seqp->ccid2s_seq); |
593f16aa | 447 | ccid2_change_srtt(hctx, r); |
2a91aa39 | 448 | hctx->ccid2hctx_rttvar = r >> 1; |
c0c736db | 449 | } else { |
2a91aa39 AB |
450 | /* RTTVAR */ |
451 | long tmp = hctx->ccid2hctx_srtt - r; | |
593f16aa AB |
452 | long srtt; |
453 | ||
2a91aa39 AB |
454 | if (tmp < 0) |
455 | tmp *= -1; | |
456 | ||
457 | tmp >>= 2; | |
458 | hctx->ccid2hctx_rttvar *= 3; | |
459 | hctx->ccid2hctx_rttvar >>= 2; | |
460 | hctx->ccid2hctx_rttvar += tmp; | |
461 | ||
462 | /* SRTT */ | |
593f16aa AB |
463 | srtt = hctx->ccid2hctx_srtt; |
464 | srtt *= 7; | |
465 | srtt >>= 3; | |
2a91aa39 | 466 | tmp = r >> 3; |
593f16aa AB |
467 | srtt += tmp; |
468 | ccid2_change_srtt(hctx, srtt); | |
2a91aa39 AB |
469 | } |
470 | s = hctx->ccid2hctx_rttvar << 2; | |
471 | /* clock granularity is 1 when based on jiffies */ | |
472 | if (!s) | |
473 | s = 1; | |
474 | hctx->ccid2hctx_rto = hctx->ccid2hctx_srtt + s; | |
475 | ||
476 | /* must be at least a second */ | |
477 | s = hctx->ccid2hctx_rto / HZ; | |
478 | /* DCCP doesn't require this [but I like it cuz my code sux] */ | |
479 | #if 1 | |
480 | if (s < 1) | |
481 | hctx->ccid2hctx_rto = HZ; | |
482 | #endif | |
483 | /* max 60 seconds */ | |
484 | if (s > 60) | |
485 | hctx->ccid2hctx_rto = HZ * 60; | |
486 | ||
487 | hctx->ccid2hctx_lastrtt = jiffies; | |
488 | ||
489 | ccid2_pr_debug("srtt: %ld rttvar: %ld rto: %ld (HZ=%d) R=%lu\n", | |
8109b02b ACM |
490 | hctx->ccid2hctx_srtt, hctx->ccid2hctx_rttvar, |
491 | hctx->ccid2hctx_rto, HZ, r); | |
2a91aa39 AB |
492 | } |
493 | ||
494 | /* we got a new ack, so re-start RTO timer */ | |
77ff72d5 | 495 | ccid2_hc_tx_kill_rto_timer(sk); |
2a91aa39 AB |
496 | ccid2_start_rto_timer(sk); |
497 | } | |
498 | ||
77ff72d5 | 499 | static void ccid2_hc_tx_dec_pipe(struct sock *sk) |
2a91aa39 | 500 | { |
77ff72d5 AB |
501 | struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk); |
502 | ||
95b21d7e GR |
503 | if (hctx->ccid2hctx_pipe == 0) |
504 | DCCP_BUG("pipe == 0"); | |
505 | else | |
506 | hctx->ccid2hctx_pipe--; | |
2a91aa39 AB |
507 | |
508 | if (hctx->ccid2hctx_pipe == 0) | |
77ff72d5 | 509 | ccid2_hc_tx_kill_rto_timer(sk); |
2a91aa39 AB |
510 | } |
511 | ||
d50ad163 | 512 | static void ccid2_congestion_event(struct sock *sk, struct ccid2_seq *seqp) |
374bcf32 | 513 | { |
d50ad163 GR |
514 | struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk); |
515 | ||
374bcf32 AB |
516 | if (time_before(seqp->ccid2s_sent, hctx->ccid2hctx_last_cong)) { |
517 | ccid2_pr_debug("Multiple losses in an RTT---treating as one\n"); | |
518 | return; | |
519 | } | |
520 | ||
521 | hctx->ccid2hctx_last_cong = jiffies; | |
522 | ||
3deeadd7 GR |
523 | hctx->ccid2hctx_cwnd = hctx->ccid2hctx_cwnd / 2 ? : 1U; |
524 | hctx->ccid2hctx_ssthresh = max(hctx->ccid2hctx_cwnd, 2U); | |
d50ad163 GR |
525 | |
526 | /* Avoid spurious timeouts resulting from Ack Ratio > cwnd */ | |
527 | if (dccp_sk(sk)->dccps_l_ack_ratio > hctx->ccid2hctx_cwnd) | |
528 | ccid2_change_l_ack_ratio(sk, hctx->ccid2hctx_cwnd); | |
374bcf32 AB |
529 | } |
530 | ||
2a91aa39 AB |
531 | static void ccid2_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb) |
532 | { | |
533 | struct dccp_sock *dp = dccp_sk(sk); | |
534 | struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk); | |
535 | u64 ackno, seqno; | |
536 | struct ccid2_seq *seqp; | |
537 | unsigned char *vector; | |
538 | unsigned char veclen; | |
539 | int offset = 0; | |
540 | int done = 0; | |
2a91aa39 AB |
541 | unsigned int maxincr = 0; |
542 | ||
543 | ccid2_hc_tx_check_sanity(hctx); | |
544 | /* check reverse path congestion */ | |
545 | seqno = DCCP_SKB_CB(skb)->dccpd_seq; | |
546 | ||
547 | /* XXX this whole "algorithm" is broken. Need to fix it to keep track | |
548 | * of the seqnos of the dupacks so that rpseq and rpdupack are correct | |
549 | * -sorbo. | |
550 | */ | |
551 | /* need to bootstrap */ | |
552 | if (hctx->ccid2hctx_rpdupack == -1) { | |
553 | hctx->ccid2hctx_rpdupack = 0; | |
554 | hctx->ccid2hctx_rpseq = seqno; | |
c0c736db | 555 | } else { |
2a91aa39 | 556 | /* check if packet is consecutive */ |
5e28599a GR |
557 | if (dccp_delta_seqno(hctx->ccid2hctx_rpseq, seqno) == 1) |
558 | hctx->ccid2hctx_rpseq = seqno; | |
2a91aa39 AB |
559 | /* it's a later packet */ |
560 | else if (after48(seqno, hctx->ccid2hctx_rpseq)) { | |
561 | hctx->ccid2hctx_rpdupack++; | |
562 | ||
563 | /* check if we got enough dupacks */ | |
63df18ad | 564 | if (hctx->ccid2hctx_rpdupack >= NUMDUPACK) { |
2a91aa39 AB |
565 | hctx->ccid2hctx_rpdupack = -1; /* XXX lame */ |
566 | hctx->ccid2hctx_rpseq = 0; | |
567 | ||
df054e1d | 568 | ccid2_change_l_ack_ratio(sk, 2 * dp->dccps_l_ack_ratio); |
2a91aa39 AB |
569 | } |
570 | } | |
571 | } | |
572 | ||
573 | /* check forward path congestion */ | |
574 | /* still didn't send out new data packets */ | |
575 | if (hctx->ccid2hctx_seqh == hctx->ccid2hctx_seqt) | |
576 | return; | |
577 | ||
578 | switch (DCCP_SKB_CB(skb)->dccpd_type) { | |
579 | case DCCP_PKT_ACK: | |
580 | case DCCP_PKT_DATAACK: | |
581 | break; | |
2a91aa39 AB |
582 | default: |
583 | return; | |
584 | } | |
585 | ||
586 | ackno = DCCP_SKB_CB(skb)->dccpd_ack_seq; | |
32aac18d AB |
587 | if (after48(ackno, hctx->ccid2hctx_high_ack)) |
588 | hctx->ccid2hctx_high_ack = ackno; | |
589 | ||
590 | seqp = hctx->ccid2hctx_seqt; | |
591 | while (before48(seqp->ccid2s_seq, ackno)) { | |
592 | seqp = seqp->ccid2s_next; | |
593 | if (seqp == hctx->ccid2hctx_seqh) { | |
594 | seqp = hctx->ccid2hctx_seqh->ccid2s_prev; | |
595 | break; | |
596 | } | |
597 | } | |
2a91aa39 AB |
598 | |
599 | /* If in slow-start, cwnd can increase at most Ack Ratio / 2 packets for | |
600 | * this single ack. I round up. | |
601 | * -sorbo. | |
602 | */ | |
603 | maxincr = dp->dccps_l_ack_ratio >> 1; | |
604 | maxincr++; | |
605 | ||
606 | /* go through all ack vectors */ | |
607 | while ((offset = ccid2_ackvector(sk, skb, offset, | |
608 | &vector, &veclen)) != -1) { | |
609 | /* go through this ack vector */ | |
610 | while (veclen--) { | |
611 | const u8 rl = *vector & DCCP_ACKVEC_LEN_MASK; | |
cfbbeabc | 612 | u64 ackno_end_rl = SUB48(ackno, rl); |
2a91aa39 | 613 | |
234af484 RD |
614 | ccid2_pr_debug("ackvec start:%llu end:%llu\n", |
615 | (unsigned long long)ackno, | |
616 | (unsigned long long)ackno_end_rl); | |
2a91aa39 AB |
617 | /* if the seqno we are analyzing is larger than the |
618 | * current ackno, then move towards the tail of our | |
619 | * seqnos. | |
620 | */ | |
621 | while (after48(seqp->ccid2s_seq, ackno)) { | |
622 | if (seqp == hctx->ccid2hctx_seqt) { | |
623 | done = 1; | |
624 | break; | |
625 | } | |
626 | seqp = seqp->ccid2s_prev; | |
627 | } | |
628 | if (done) | |
629 | break; | |
630 | ||
631 | /* check all seqnos in the range of the vector | |
632 | * run length | |
633 | */ | |
634 | while (between48(seqp->ccid2s_seq,ackno_end_rl,ackno)) { | |
8e27e465 AB |
635 | const u8 state = *vector & |
636 | DCCP_ACKVEC_STATE_MASK; | |
2a91aa39 AB |
637 | |
638 | /* new packet received or marked */ | |
639 | if (state != DCCP_ACKVEC_STATE_NOT_RECEIVED && | |
640 | !seqp->ccid2s_acked) { | |
8109b02b | 641 | if (state == |
2a91aa39 | 642 | DCCP_ACKVEC_STATE_ECN_MARKED) { |
d50ad163 | 643 | ccid2_congestion_event(sk, |
374bcf32 | 644 | seqp); |
c0c736db | 645 | } else |
2a91aa39 AB |
646 | ccid2_new_ack(sk, seqp, |
647 | &maxincr); | |
2a91aa39 AB |
648 | |
649 | seqp->ccid2s_acked = 1; | |
650 | ccid2_pr_debug("Got ack for %llu\n", | |
234af484 | 651 | (unsigned long long)seqp->ccid2s_seq); |
77ff72d5 | 652 | ccid2_hc_tx_dec_pipe(sk); |
2a91aa39 AB |
653 | } |
654 | if (seqp == hctx->ccid2hctx_seqt) { | |
655 | done = 1; | |
656 | break; | |
657 | } | |
3de5489f | 658 | seqp = seqp->ccid2s_prev; |
2a91aa39 AB |
659 | } |
660 | if (done) | |
661 | break; | |
662 | ||
cfbbeabc | 663 | ackno = SUB48(ackno_end_rl, 1); |
2a91aa39 AB |
664 | vector++; |
665 | } | |
666 | if (done) | |
667 | break; | |
668 | } | |
669 | ||
670 | /* The state about what is acked should be correct now | |
671 | * Check for NUMDUPACK | |
672 | */ | |
32aac18d AB |
673 | seqp = hctx->ccid2hctx_seqt; |
674 | while (before48(seqp->ccid2s_seq, hctx->ccid2hctx_high_ack)) { | |
675 | seqp = seqp->ccid2s_next; | |
676 | if (seqp == hctx->ccid2hctx_seqh) { | |
677 | seqp = hctx->ccid2hctx_seqh->ccid2s_prev; | |
678 | break; | |
679 | } | |
680 | } | |
2a91aa39 AB |
681 | done = 0; |
682 | while (1) { | |
683 | if (seqp->ccid2s_acked) { | |
684 | done++; | |
63df18ad | 685 | if (done == NUMDUPACK) |
2a91aa39 | 686 | break; |
2a91aa39 | 687 | } |
c0c736db | 688 | if (seqp == hctx->ccid2hctx_seqt) |
2a91aa39 | 689 | break; |
2a91aa39 AB |
690 | seqp = seqp->ccid2s_prev; |
691 | } | |
692 | ||
693 | /* If there are at least 3 acknowledgements, anything unacknowledged | |
694 | * below the last sequence number is considered lost | |
695 | */ | |
63df18ad | 696 | if (done == NUMDUPACK) { |
2a91aa39 AB |
697 | struct ccid2_seq *last_acked = seqp; |
698 | ||
699 | /* check for lost packets */ | |
700 | while (1) { | |
701 | if (!seqp->ccid2s_acked) { | |
374bcf32 | 702 | ccid2_pr_debug("Packet lost: %llu\n", |
234af484 | 703 | (unsigned long long)seqp->ccid2s_seq); |
374bcf32 AB |
704 | /* XXX need to traverse from tail -> head in |
705 | * order to detect multiple congestion events in | |
706 | * one ack vector. | |
707 | */ | |
d50ad163 | 708 | ccid2_congestion_event(sk, seqp); |
77ff72d5 | 709 | ccid2_hc_tx_dec_pipe(sk); |
2a91aa39 AB |
710 | } |
711 | if (seqp == hctx->ccid2hctx_seqt) | |
712 | break; | |
713 | seqp = seqp->ccid2s_prev; | |
714 | } | |
715 | ||
716 | hctx->ccid2hctx_seqt = last_acked; | |
717 | } | |
718 | ||
719 | /* trim acked packets in tail */ | |
720 | while (hctx->ccid2hctx_seqt != hctx->ccid2hctx_seqh) { | |
721 | if (!hctx->ccid2hctx_seqt->ccid2s_acked) | |
722 | break; | |
723 | ||
724 | hctx->ccid2hctx_seqt = hctx->ccid2hctx_seqt->ccid2s_next; | |
725 | } | |
726 | ||
2a91aa39 AB |
727 | ccid2_hc_tx_check_sanity(hctx); |
728 | } | |
729 | ||
91f0ebf7 | 730 | static int ccid2_hc_tx_init(struct ccid *ccid, struct sock *sk) |
2a91aa39 | 731 | { |
c9eaf173 | 732 | struct ccid2_hc_tx_sock *hctx = ccid_priv(ccid); |
b00d2bbc GR |
733 | struct dccp_sock *dp = dccp_sk(sk); |
734 | u32 max_ratio; | |
2a91aa39 | 735 | |
b00d2bbc | 736 | /* RFC 4341, 5: initialise ssthresh to arbitrarily high (max) value */ |
3deeadd7 | 737 | hctx->ccid2hctx_ssthresh = ~0U; |
2a91aa39 | 738 | |
b00d2bbc GR |
739 | /* |
740 | * RFC 4341, 5: "The cwnd parameter is initialized to at most four | |
741 | * packets for new connections, following the rules from [RFC3390]". | |
742 | * We need to convert the bytes of RFC3390 into the packets of RFC 4341. | |
743 | */ | |
744 | hctx->ccid2hctx_cwnd = min(4U, max(2U, 4380U / dp->dccps_mss_cache)); | |
745 | ||
746 | /* Make sure that Ack Ratio is enabled and within bounds. */ | |
747 | max_ratio = DIV_ROUND_UP(hctx->ccid2hctx_cwnd, 2); | |
748 | if (dp->dccps_l_ack_ratio == 0 || dp->dccps_l_ack_ratio > max_ratio) | |
749 | dp->dccps_l_ack_ratio = max_ratio; | |
750 | ||
2a91aa39 | 751 | /* XXX init ~ to window size... */ |
cd1f7d34 | 752 | if (ccid2_hc_tx_alloc_seq(hctx)) |
2a91aa39 | 753 | return -ENOMEM; |
91f0ebf7 | 754 | |
2a91aa39 | 755 | hctx->ccid2hctx_rto = 3 * HZ; |
593f16aa | 756 | ccid2_change_srtt(hctx, -1); |
2a91aa39 | 757 | hctx->ccid2hctx_rttvar = -1; |
2a91aa39 | 758 | hctx->ccid2hctx_rpdupack = -1; |
374bcf32 | 759 | hctx->ccid2hctx_last_cong = jiffies; |
b24b8a24 PE |
760 | setup_timer(&hctx->ccid2hctx_rtotimer, ccid2_hc_tx_rto_expire, |
761 | (unsigned long)sk); | |
2a91aa39 AB |
762 | |
763 | ccid2_hc_tx_check_sanity(hctx); | |
764 | return 0; | |
765 | } | |
766 | ||
767 | static void ccid2_hc_tx_exit(struct sock *sk) | |
768 | { | |
c9eaf173 | 769 | struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk); |
07978aab | 770 | int i; |
2a91aa39 | 771 | |
77ff72d5 | 772 | ccid2_hc_tx_kill_rto_timer(sk); |
07978aab AB |
773 | |
774 | for (i = 0; i < hctx->ccid2hctx_seqbufc; i++) | |
775 | kfree(hctx->ccid2hctx_seqbuf[i]); | |
776 | hctx->ccid2hctx_seqbufc = 0; | |
2a91aa39 AB |
777 | } |
778 | ||
779 | static void ccid2_hc_rx_packet_recv(struct sock *sk, struct sk_buff *skb) | |
780 | { | |
781 | const struct dccp_sock *dp = dccp_sk(sk); | |
782 | struct ccid2_hc_rx_sock *hcrx = ccid2_hc_rx_sk(sk); | |
783 | ||
784 | switch (DCCP_SKB_CB(skb)->dccpd_type) { | |
785 | case DCCP_PKT_DATA: | |
786 | case DCCP_PKT_DATAACK: | |
787 | hcrx->ccid2hcrx_data++; | |
788 | if (hcrx->ccid2hcrx_data >= dp->dccps_r_ack_ratio) { | |
789 | dccp_send_ack(sk); | |
790 | hcrx->ccid2hcrx_data = 0; | |
791 | } | |
792 | break; | |
793 | } | |
794 | } | |
795 | ||
91f0ebf7 | 796 | static struct ccid_operations ccid2 = { |
3dd9a7c3 | 797 | .ccid_id = DCCPC_CCID2, |
2a91aa39 AB |
798 | .ccid_name = "ccid2", |
799 | .ccid_owner = THIS_MODULE, | |
91f0ebf7 | 800 | .ccid_hc_tx_obj_size = sizeof(struct ccid2_hc_tx_sock), |
2a91aa39 AB |
801 | .ccid_hc_tx_init = ccid2_hc_tx_init, |
802 | .ccid_hc_tx_exit = ccid2_hc_tx_exit, | |
803 | .ccid_hc_tx_send_packet = ccid2_hc_tx_send_packet, | |
804 | .ccid_hc_tx_packet_sent = ccid2_hc_tx_packet_sent, | |
805 | .ccid_hc_tx_packet_recv = ccid2_hc_tx_packet_recv, | |
91f0ebf7 | 806 | .ccid_hc_rx_obj_size = sizeof(struct ccid2_hc_rx_sock), |
2a91aa39 AB |
807 | .ccid_hc_rx_packet_recv = ccid2_hc_rx_packet_recv, |
808 | }; | |
809 | ||
84116716 | 810 | #ifdef CONFIG_IP_DCCP_CCID2_DEBUG |
042d18f9 | 811 | module_param(ccid2_debug, bool, 0444); |
2a91aa39 | 812 | MODULE_PARM_DESC(ccid2_debug, "Enable debug messages"); |
84116716 | 813 | #endif |
2a91aa39 AB |
814 | |
815 | static __init int ccid2_module_init(void) | |
816 | { | |
817 | return ccid_register(&ccid2); | |
818 | } | |
819 | module_init(ccid2_module_init); | |
820 | ||
821 | static __exit void ccid2_module_exit(void) | |
822 | { | |
823 | ccid_unregister(&ccid2); | |
824 | } | |
825 | module_exit(ccid2_module_exit); | |
826 | ||
827 | MODULE_AUTHOR("Andrea Bittau <a.bittau@cs.ucl.ac.uk>"); | |
c0c736db | 828 | MODULE_DESCRIPTION("DCCP TCP-Like (CCID2) CCID"); |
2a91aa39 AB |
829 | MODULE_LICENSE("GPL"); |
830 | MODULE_ALIAS("net-dccp-ccid-2"); |