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2a91aa39 | 1 | /* |
2a91aa39 AB |
2 | * Copyright (c) 2005, 2006 Andrea Bittau <a.bittau@cs.ucl.ac.uk> |
3 | * | |
4 | * Changes to meet Linux coding standards, and DCCP infrastructure fixes. | |
5 | * | |
6 | * Copyright (c) 2006 Arnaldo Carvalho de Melo <acme@conectiva.com.br> | |
7 | * | |
8 | * This program is free software; you can redistribute it and/or modify | |
9 | * it under the terms of the GNU General Public License as published by | |
10 | * the Free Software Foundation; either version 2 of the License, or | |
11 | * (at your option) any later version. | |
12 | * | |
13 | * This program is distributed in the hope that it will be useful, | |
14 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
15 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
16 | * GNU General Public License for more details. | |
17 | * | |
18 | * You should have received a copy of the GNU General Public License | |
19 | * along with this program; if not, write to the Free Software | |
20 | * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. | |
21 | */ | |
22 | ||
23 | /* | |
0e64e94e | 24 | * This implementation should follow RFC 4341 |
2a91aa39 | 25 | */ |
e8ef967a | 26 | #include "../feat.h" |
2a91aa39 AB |
27 | #include "../ccid.h" |
28 | #include "../dccp.h" | |
29 | #include "ccid2.h" | |
30 | ||
2a91aa39 | 31 | |
8d424f6c | 32 | #ifdef CONFIG_IP_DCCP_CCID2_DEBUG |
84116716 GR |
33 | static int ccid2_debug; |
34 | #define ccid2_pr_debug(format, a...) DCCP_PR_DEBUG(ccid2_debug, format, ##a) | |
410e27a4 GR |
35 | |
36 | static void ccid2_hc_tx_check_sanity(const struct ccid2_hc_tx_sock *hctx) | |
37 | { | |
38 | int len = 0; | |
39 | int pipe = 0; | |
40 | struct ccid2_seq *seqp = hctx->ccid2hctx_seqh; | |
41 | ||
42 | /* there is data in the chain */ | |
43 | if (seqp != hctx->ccid2hctx_seqt) { | |
44 | seqp = seqp->ccid2s_prev; | |
45 | len++; | |
46 | if (!seqp->ccid2s_acked) | |
47 | pipe++; | |
48 | ||
49 | while (seqp != hctx->ccid2hctx_seqt) { | |
50 | struct ccid2_seq *prev = seqp->ccid2s_prev; | |
51 | ||
52 | len++; | |
53 | if (!prev->ccid2s_acked) | |
54 | pipe++; | |
55 | ||
56 | /* packets are sent sequentially */ | |
57 | BUG_ON(dccp_delta_seqno(seqp->ccid2s_seq, | |
58 | prev->ccid2s_seq ) >= 0); | |
59 | BUG_ON(time_before(seqp->ccid2s_sent, | |
60 | prev->ccid2s_sent)); | |
61 | ||
62 | seqp = prev; | |
63 | } | |
64 | } | |
65 | ||
66 | BUG_ON(pipe != hctx->ccid2hctx_pipe); | |
67 | ccid2_pr_debug("len of chain=%d\n", len); | |
68 | ||
69 | do { | |
70 | seqp = seqp->ccid2s_prev; | |
71 | len++; | |
72 | } while (seqp != hctx->ccid2hctx_seqh); | |
73 | ||
74 | ccid2_pr_debug("total len=%d\n", len); | |
75 | BUG_ON(len != hctx->ccid2hctx_seqbufc * CCID2_SEQBUF_LEN); | |
76 | } | |
2a91aa39 | 77 | #else |
84116716 | 78 | #define ccid2_pr_debug(format, a...) |
410e27a4 | 79 | #define ccid2_hc_tx_check_sanity(hctx) |
2a91aa39 AB |
80 | #endif |
81 | ||
cd1f7d34 | 82 | static int ccid2_hc_tx_alloc_seq(struct ccid2_hc_tx_sock *hctx) |
07978aab AB |
83 | { |
84 | struct ccid2_seq *seqp; | |
85 | int i; | |
86 | ||
87 | /* check if we have space to preserve the pointer to the buffer */ | |
410e27a4 GR |
88 | if (hctx->ccid2hctx_seqbufc >= (sizeof(hctx->ccid2hctx_seqbuf) / |
89 | sizeof(struct ccid2_seq*))) | |
07978aab AB |
90 | return -ENOMEM; |
91 | ||
92 | /* allocate buffer and initialize linked list */ | |
cd1f7d34 | 93 | seqp = kmalloc(CCID2_SEQBUF_LEN * sizeof(struct ccid2_seq), gfp_any()); |
07978aab AB |
94 | if (seqp == NULL) |
95 | return -ENOMEM; | |
96 | ||
cd1f7d34 | 97 | for (i = 0; i < (CCID2_SEQBUF_LEN - 1); i++) { |
07978aab AB |
98 | seqp[i].ccid2s_next = &seqp[i + 1]; |
99 | seqp[i + 1].ccid2s_prev = &seqp[i]; | |
100 | } | |
cd1f7d34 GR |
101 | seqp[CCID2_SEQBUF_LEN - 1].ccid2s_next = seqp; |
102 | seqp->ccid2s_prev = &seqp[CCID2_SEQBUF_LEN - 1]; | |
07978aab AB |
103 | |
104 | /* This is the first allocation. Initiate the head and tail. */ | |
410e27a4 GR |
105 | if (hctx->ccid2hctx_seqbufc == 0) |
106 | hctx->ccid2hctx_seqh = hctx->ccid2hctx_seqt = seqp; | |
07978aab AB |
107 | else { |
108 | /* link the existing list with the one we just created */ | |
410e27a4 GR |
109 | hctx->ccid2hctx_seqh->ccid2s_next = seqp; |
110 | seqp->ccid2s_prev = hctx->ccid2hctx_seqh; | |
07978aab | 111 | |
410e27a4 GR |
112 | hctx->ccid2hctx_seqt->ccid2s_prev = &seqp[CCID2_SEQBUF_LEN - 1]; |
113 | seqp[CCID2_SEQBUF_LEN - 1].ccid2s_next = hctx->ccid2hctx_seqt; | |
07978aab AB |
114 | } |
115 | ||
116 | /* store the original pointer to the buffer so we can free it */ | |
410e27a4 GR |
117 | hctx->ccid2hctx_seqbuf[hctx->ccid2hctx_seqbufc] = seqp; |
118 | hctx->ccid2hctx_seqbufc++; | |
07978aab AB |
119 | |
120 | return 0; | |
121 | } | |
122 | ||
6b57c93d | 123 | static int ccid2_hc_tx_send_packet(struct sock *sk, struct sk_buff *skb) |
2a91aa39 | 124 | { |
410e27a4 GR |
125 | struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk); |
126 | ||
127 | if (hctx->ccid2hctx_pipe < hctx->ccid2hctx_cwnd) | |
128 | return 0; | |
129 | ||
130 | return 1; /* XXX CCID should dequeue when ready instead of polling */ | |
2a91aa39 AB |
131 | } |
132 | ||
df054e1d | 133 | static void ccid2_change_l_ack_ratio(struct sock *sk, u32 val) |
2a91aa39 AB |
134 | { |
135 | struct dccp_sock *dp = dccp_sk(sk); | |
410e27a4 | 136 | u32 max_ratio = DIV_ROUND_UP(ccid2_hc_tx_sk(sk)->ccid2hctx_cwnd, 2); |
d50ad163 | 137 | |
2a91aa39 | 138 | /* |
d50ad163 GR |
139 | * Ensure that Ack Ratio does not exceed ceil(cwnd/2), which is (2) from |
140 | * RFC 4341, 6.1.2. We ignore the statement that Ack Ratio 2 is always | |
141 | * acceptable since this causes starvation/deadlock whenever cwnd < 2. | |
142 | * The same problem arises when Ack Ratio is 0 (ie. Ack Ratio disabled). | |
2a91aa39 | 143 | */ |
d50ad163 GR |
144 | if (val == 0 || val > max_ratio) { |
145 | DCCP_WARN("Limiting Ack Ratio (%u) to %u\n", val, max_ratio); | |
146 | val = max_ratio; | |
2a91aa39 | 147 | } |
e8ef967a GR |
148 | if (val > DCCPF_ACK_RATIO_MAX) |
149 | val = DCCPF_ACK_RATIO_MAX; | |
2a91aa39 | 150 | |
d50ad163 GR |
151 | if (val == dp->dccps_l_ack_ratio) |
152 | return; | |
153 | ||
df054e1d | 154 | ccid2_pr_debug("changing local ack ratio to %u\n", val); |
2a91aa39 AB |
155 | dp->dccps_l_ack_ratio = val; |
156 | } | |
157 | ||
410e27a4 GR |
158 | static void ccid2_change_srtt(struct ccid2_hc_tx_sock *hctx, long val) |
159 | { | |
160 | ccid2_pr_debug("change SRTT to %ld\n", val); | |
161 | hctx->ccid2hctx_srtt = val; | |
162 | } | |
163 | ||
164 | static void ccid2_start_rto_timer(struct sock *sk); | |
165 | ||
2a91aa39 AB |
166 | static void ccid2_hc_tx_rto_expire(unsigned long data) |
167 | { | |
168 | struct sock *sk = (struct sock *)data; | |
169 | struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk); | |
410e27a4 | 170 | long s; |
2a91aa39 | 171 | |
2a91aa39 AB |
172 | bh_lock_sock(sk); |
173 | if (sock_owned_by_user(sk)) { | |
410e27a4 GR |
174 | sk_reset_timer(sk, &hctx->ccid2hctx_rtotimer, |
175 | jiffies + HZ / 5); | |
2a91aa39 AB |
176 | goto out; |
177 | } | |
178 | ||
179 | ccid2_pr_debug("RTO_EXPIRE\n"); | |
180 | ||
410e27a4 GR |
181 | ccid2_hc_tx_check_sanity(hctx); |
182 | ||
2a91aa39 | 183 | /* back-off timer */ |
410e27a4 GR |
184 | hctx->ccid2hctx_rto <<= 1; |
185 | ||
186 | s = hctx->ccid2hctx_rto / HZ; | |
187 | if (s > 60) | |
188 | hctx->ccid2hctx_rto = 60 * HZ; | |
189 | ||
190 | ccid2_start_rto_timer(sk); | |
2a91aa39 | 191 | |
2a91aa39 | 192 | /* adjust pipe, cwnd etc */ |
410e27a4 GR |
193 | hctx->ccid2hctx_ssthresh = hctx->ccid2hctx_cwnd / 2; |
194 | if (hctx->ccid2hctx_ssthresh < 2) | |
195 | hctx->ccid2hctx_ssthresh = 2; | |
196 | hctx->ccid2hctx_cwnd = 1; | |
197 | hctx->ccid2hctx_pipe = 0; | |
2a91aa39 AB |
198 | |
199 | /* clear state about stuff we sent */ | |
410e27a4 GR |
200 | hctx->ccid2hctx_seqt = hctx->ccid2hctx_seqh; |
201 | hctx->ccid2hctx_packets_acked = 0; | |
2a91aa39 AB |
202 | |
203 | /* clear ack ratio state. */ | |
410e27a4 GR |
204 | hctx->ccid2hctx_rpseq = 0; |
205 | hctx->ccid2hctx_rpdupack = -1; | |
2a91aa39 | 206 | ccid2_change_l_ack_ratio(sk, 1); |
410e27a4 | 207 | ccid2_hc_tx_check_sanity(hctx); |
2a91aa39 AB |
208 | out: |
209 | bh_unlock_sock(sk); | |
77ff72d5 | 210 | sock_put(sk); |
2a91aa39 AB |
211 | } |
212 | ||
410e27a4 GR |
213 | static void ccid2_start_rto_timer(struct sock *sk) |
214 | { | |
215 | struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk); | |
216 | ||
217 | ccid2_pr_debug("setting RTO timeout=%ld\n", hctx->ccid2hctx_rto); | |
218 | ||
219 | BUG_ON(timer_pending(&hctx->ccid2hctx_rtotimer)); | |
220 | sk_reset_timer(sk, &hctx->ccid2hctx_rtotimer, | |
221 | jiffies + hctx->ccid2hctx_rto); | |
222 | } | |
223 | ||
224 | static void ccid2_hc_tx_packet_sent(struct sock *sk, int more, unsigned int len) | |
2a91aa39 AB |
225 | { |
226 | struct dccp_sock *dp = dccp_sk(sk); | |
227 | struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk); | |
07978aab | 228 | struct ccid2_seq *next; |
2a91aa39 | 229 | |
410e27a4 | 230 | hctx->ccid2hctx_pipe++; |
2a91aa39 | 231 | |
410e27a4 GR |
232 | hctx->ccid2hctx_seqh->ccid2s_seq = dp->dccps_gss; |
233 | hctx->ccid2hctx_seqh->ccid2s_acked = 0; | |
234 | hctx->ccid2hctx_seqh->ccid2s_sent = jiffies; | |
2a91aa39 | 235 | |
410e27a4 | 236 | next = hctx->ccid2hctx_seqh->ccid2s_next; |
07978aab | 237 | /* check if we need to alloc more space */ |
410e27a4 | 238 | if (next == hctx->ccid2hctx_seqt) { |
7d9e8931 GR |
239 | if (ccid2_hc_tx_alloc_seq(hctx)) { |
240 | DCCP_CRIT("packet history - out of memory!"); | |
241 | /* FIXME: find a more graceful way to bail out */ | |
242 | return; | |
243 | } | |
410e27a4 GR |
244 | next = hctx->ccid2hctx_seqh->ccid2s_next; |
245 | BUG_ON(next == hctx->ccid2hctx_seqt); | |
2a91aa39 | 246 | } |
410e27a4 | 247 | hctx->ccid2hctx_seqh = next; |
07978aab | 248 | |
410e27a4 GR |
249 | ccid2_pr_debug("cwnd=%d pipe=%d\n", hctx->ccid2hctx_cwnd, |
250 | hctx->ccid2hctx_pipe); | |
2a91aa39 | 251 | |
900bfed4 GR |
252 | /* |
253 | * FIXME: The code below is broken and the variables have been removed | |
254 | * from the socket struct. The `ackloss' variable was always set to 0, | |
255 | * and with arsent there are several problems: | |
256 | * (i) it doesn't just count the number of Acks, but all sent packets; | |
257 | * (ii) it is expressed in # of packets, not # of windows, so the | |
258 | * comparison below uses the wrong formula: Appendix A of RFC 4341 | |
259 | * comes up with the number K = cwnd / (R^2 - R) of consecutive windows | |
260 | * of data with no lost or marked Ack packets. If arsent were the # of | |
261 | * consecutive Acks received without loss, then Ack Ratio needs to be | |
262 | * decreased by 1 when | |
263 | * arsent >= K * cwnd / R = cwnd^2 / (R^3 - R^2) | |
264 | * where cwnd / R is the number of Acks received per window of data | |
265 | * (cf. RFC 4341, App. A). The problems are that | |
266 | * - arsent counts other packets as well; | |
267 | * - the comparison uses a formula different from RFC 4341; | |
268 | * - computing a cubic/quadratic equation each time is too complicated. | |
269 | * Hence a different algorithm is needed. | |
270 | */ | |
271 | #if 0 | |
2a91aa39 | 272 | /* Ack Ratio. Need to maintain a concept of how many windows we sent */ |
410e27a4 | 273 | hctx->ccid2hctx_arsent++; |
2a91aa39 | 274 | /* We had an ack loss in this window... */ |
410e27a4 GR |
275 | if (hctx->ccid2hctx_ackloss) { |
276 | if (hctx->ccid2hctx_arsent >= hctx->ccid2hctx_cwnd) { | |
277 | hctx->ccid2hctx_arsent = 0; | |
278 | hctx->ccid2hctx_ackloss = 0; | |
2a91aa39 | 279 | } |
c0c736db ACM |
280 | } else { |
281 | /* No acks lost up to now... */ | |
2a91aa39 AB |
282 | /* decrease ack ratio if enough packets were sent */ |
283 | if (dp->dccps_l_ack_ratio > 1) { | |
284 | /* XXX don't calculate denominator each time */ | |
c0c736db ACM |
285 | int denom = dp->dccps_l_ack_ratio * dp->dccps_l_ack_ratio - |
286 | dp->dccps_l_ack_ratio; | |
2a91aa39 | 287 | |
410e27a4 | 288 | denom = hctx->ccid2hctx_cwnd * hctx->ccid2hctx_cwnd / denom; |
2a91aa39 | 289 | |
410e27a4 | 290 | if (hctx->ccid2hctx_arsent >= denom) { |
2a91aa39 | 291 | ccid2_change_l_ack_ratio(sk, dp->dccps_l_ack_ratio - 1); |
410e27a4 | 292 | hctx->ccid2hctx_arsent = 0; |
2a91aa39 | 293 | } |
c0c736db ACM |
294 | } else { |
295 | /* we can't increase ack ratio further [1] */ | |
410e27a4 | 296 | hctx->ccid2hctx_arsent = 0; /* or maybe set it to cwnd*/ |
2a91aa39 AB |
297 | } |
298 | } | |
900bfed4 | 299 | #endif |
2a91aa39 AB |
300 | |
301 | /* setup RTO timer */ | |
410e27a4 GR |
302 | if (!timer_pending(&hctx->ccid2hctx_rtotimer)) |
303 | ccid2_start_rto_timer(sk); | |
c0c736db | 304 | |
8d424f6c | 305 | #ifdef CONFIG_IP_DCCP_CCID2_DEBUG |
2a91aa39 | 306 | do { |
410e27a4 | 307 | struct ccid2_seq *seqp = hctx->ccid2hctx_seqt; |
2a91aa39 | 308 | |
410e27a4 | 309 | while (seqp != hctx->ccid2hctx_seqh) { |
2a91aa39 | 310 | ccid2_pr_debug("out seq=%llu acked=%d time=%lu\n", |
8109b02b | 311 | (unsigned long long)seqp->ccid2s_seq, |
234af484 | 312 | seqp->ccid2s_acked, seqp->ccid2s_sent); |
2a91aa39 AB |
313 | seqp = seqp->ccid2s_next; |
314 | } | |
c0c736db | 315 | } while (0); |
2a91aa39 | 316 | ccid2_pr_debug("=========\n"); |
410e27a4 | 317 | ccid2_hc_tx_check_sanity(hctx); |
2a91aa39 AB |
318 | #endif |
319 | } | |
320 | ||
410e27a4 GR |
321 | /* XXX Lame code duplication! |
322 | * returns -1 if none was found. | |
323 | * else returns the next offset to use in the function call. | |
1435562d | 324 | */ |
410e27a4 GR |
325 | static int ccid2_ackvector(struct sock *sk, struct sk_buff *skb, int offset, |
326 | unsigned char **vec, unsigned char *veclen) | |
1435562d | 327 | { |
410e27a4 GR |
328 | const struct dccp_hdr *dh = dccp_hdr(skb); |
329 | unsigned char *options = (unsigned char *)dh + dccp_hdr_len(skb); | |
330 | unsigned char *opt_ptr; | |
331 | const unsigned char *opt_end = (unsigned char *)dh + | |
332 | (dh->dccph_doff * 4); | |
333 | unsigned char opt, len; | |
334 | unsigned char *value; | |
335 | ||
336 | BUG_ON(offset < 0); | |
337 | options += offset; | |
338 | opt_ptr = options; | |
339 | if (opt_ptr >= opt_end) | |
340 | return -1; | |
341 | ||
342 | while (opt_ptr != opt_end) { | |
343 | opt = *opt_ptr++; | |
344 | len = 0; | |
345 | value = NULL; | |
346 | ||
347 | /* Check if this isn't a single byte option */ | |
348 | if (opt > DCCPO_MAX_RESERVED) { | |
349 | if (opt_ptr == opt_end) | |
350 | goto out_invalid_option; | |
351 | ||
352 | len = *opt_ptr++; | |
353 | if (len < 3) | |
354 | goto out_invalid_option; | |
1435562d | 355 | /* |
410e27a4 GR |
356 | * Remove the type and len fields, leaving |
357 | * just the value size | |
1435562d | 358 | */ |
410e27a4 GR |
359 | len -= 2; |
360 | value = opt_ptr; | |
361 | opt_ptr += len; | |
1435562d | 362 | |
410e27a4 GR |
363 | if (opt_ptr > opt_end) |
364 | goto out_invalid_option; | |
1435562d GR |
365 | } |
366 | ||
410e27a4 GR |
367 | switch (opt) { |
368 | case DCCPO_ACK_VECTOR_0: | |
369 | case DCCPO_ACK_VECTOR_1: | |
370 | *vec = value; | |
371 | *veclen = len; | |
372 | return offset + (opt_ptr - options); | |
1435562d GR |
373 | } |
374 | } | |
375 | ||
410e27a4 | 376 | return -1; |
1435562d | 377 | |
410e27a4 GR |
378 | out_invalid_option: |
379 | DCCP_BUG("Invalid option - this should not happen (previous parsing)!"); | |
380 | return -1; | |
1435562d GR |
381 | } |
382 | ||
410e27a4 | 383 | static void ccid2_hc_tx_kill_rto_timer(struct sock *sk) |
2a91aa39 AB |
384 | { |
385 | struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk); | |
386 | ||
410e27a4 GR |
387 | sk_stop_timer(sk, &hctx->ccid2hctx_rtotimer); |
388 | ccid2_pr_debug("deleted RTO timer\n"); | |
2a91aa39 AB |
389 | } |
390 | ||
410e27a4 GR |
391 | static inline void ccid2_new_ack(struct sock *sk, |
392 | struct ccid2_seq *seqp, | |
393 | unsigned int *maxincr) | |
374bcf32 | 394 | { |
d50ad163 GR |
395 | struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk); |
396 | ||
410e27a4 GR |
397 | if (hctx->ccid2hctx_cwnd < hctx->ccid2hctx_ssthresh) { |
398 | if (*maxincr > 0 && ++hctx->ccid2hctx_packets_acked == 2) { | |
399 | hctx->ccid2hctx_cwnd += 1; | |
400 | *maxincr -= 1; | |
401 | hctx->ccid2hctx_packets_acked = 0; | |
402 | } | |
403 | } else if (++hctx->ccid2hctx_packets_acked >= hctx->ccid2hctx_cwnd) { | |
404 | hctx->ccid2hctx_cwnd += 1; | |
405 | hctx->ccid2hctx_packets_acked = 0; | |
374bcf32 AB |
406 | } |
407 | ||
410e27a4 GR |
408 | /* update RTO */ |
409 | if (hctx->ccid2hctx_srtt == -1 || | |
410 | time_after(jiffies, hctx->ccid2hctx_lastrtt + hctx->ccid2hctx_srtt)) { | |
411 | unsigned long r = (long)jiffies - (long)seqp->ccid2s_sent; | |
412 | int s; | |
413 | ||
414 | /* first measurement */ | |
415 | if (hctx->ccid2hctx_srtt == -1) { | |
416 | ccid2_pr_debug("R: %lu Time=%lu seq=%llu\n", | |
417 | r, jiffies, | |
418 | (unsigned long long)seqp->ccid2s_seq); | |
419 | ccid2_change_srtt(hctx, r); | |
420 | hctx->ccid2hctx_rttvar = r >> 1; | |
421 | } else { | |
422 | /* RTTVAR */ | |
423 | long tmp = hctx->ccid2hctx_srtt - r; | |
424 | long srtt; | |
425 | ||
426 | if (tmp < 0) | |
427 | tmp *= -1; | |
428 | ||
429 | tmp >>= 2; | |
430 | hctx->ccid2hctx_rttvar *= 3; | |
431 | hctx->ccid2hctx_rttvar >>= 2; | |
432 | hctx->ccid2hctx_rttvar += tmp; | |
433 | ||
434 | /* SRTT */ | |
435 | srtt = hctx->ccid2hctx_srtt; | |
436 | srtt *= 7; | |
437 | srtt >>= 3; | |
438 | tmp = r >> 3; | |
439 | srtt += tmp; | |
440 | ccid2_change_srtt(hctx, srtt); | |
441 | } | |
442 | s = hctx->ccid2hctx_rttvar << 2; | |
443 | /* clock granularity is 1 when based on jiffies */ | |
444 | if (!s) | |
445 | s = 1; | |
446 | hctx->ccid2hctx_rto = hctx->ccid2hctx_srtt + s; | |
447 | ||
448 | /* must be at least a second */ | |
449 | s = hctx->ccid2hctx_rto / HZ; | |
450 | /* DCCP doesn't require this [but I like it cuz my code sux] */ | |
451 | #if 1 | |
452 | if (s < 1) | |
453 | hctx->ccid2hctx_rto = HZ; | |
454 | #endif | |
455 | /* max 60 seconds */ | |
456 | if (s > 60) | |
457 | hctx->ccid2hctx_rto = HZ * 60; | |
374bcf32 | 458 | |
410e27a4 | 459 | hctx->ccid2hctx_lastrtt = jiffies; |
d50ad163 | 460 | |
410e27a4 GR |
461 | ccid2_pr_debug("srtt: %ld rttvar: %ld rto: %ld (HZ=%d) R=%lu\n", |
462 | hctx->ccid2hctx_srtt, hctx->ccid2hctx_rttvar, | |
463 | hctx->ccid2hctx_rto, HZ, r); | |
464 | } | |
465 | ||
466 | /* we got a new ack, so re-start RTO timer */ | |
467 | ccid2_hc_tx_kill_rto_timer(sk); | |
468 | ccid2_start_rto_timer(sk); | |
374bcf32 AB |
469 | } |
470 | ||
410e27a4 | 471 | static void ccid2_hc_tx_dec_pipe(struct sock *sk) |
c8bf462b GR |
472 | { |
473 | struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk); | |
474 | ||
410e27a4 GR |
475 | if (hctx->ccid2hctx_pipe == 0) |
476 | DCCP_BUG("pipe == 0"); | |
477 | else | |
478 | hctx->ccid2hctx_pipe--; | |
479 | ||
480 | if (hctx->ccid2hctx_pipe == 0) | |
481 | ccid2_hc_tx_kill_rto_timer(sk); | |
482 | } | |
483 | ||
484 | static void ccid2_congestion_event(struct sock *sk, struct ccid2_seq *seqp) | |
485 | { | |
486 | struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk); | |
487 | ||
488 | if (time_before(seqp->ccid2s_sent, hctx->ccid2hctx_last_cong)) { | |
489 | ccid2_pr_debug("Multiple losses in an RTT---treating as one\n"); | |
490 | return; | |
c8bf462b | 491 | } |
410e27a4 GR |
492 | |
493 | hctx->ccid2hctx_last_cong = jiffies; | |
494 | ||
495 | hctx->ccid2hctx_cwnd = hctx->ccid2hctx_cwnd / 2 ? : 1U; | |
496 | hctx->ccid2hctx_ssthresh = max(hctx->ccid2hctx_cwnd, 2U); | |
497 | ||
498 | /* Avoid spurious timeouts resulting from Ack Ratio > cwnd */ | |
499 | if (dccp_sk(sk)->dccps_l_ack_ratio > hctx->ccid2hctx_cwnd) | |
500 | ccid2_change_l_ack_ratio(sk, hctx->ccid2hctx_cwnd); | |
c8bf462b GR |
501 | } |
502 | ||
2a91aa39 AB |
503 | static void ccid2_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb) |
504 | { | |
505 | struct dccp_sock *dp = dccp_sk(sk); | |
506 | struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk); | |
507 | u64 ackno, seqno; | |
508 | struct ccid2_seq *seqp; | |
410e27a4 GR |
509 | unsigned char *vector; |
510 | unsigned char veclen; | |
511 | int offset = 0; | |
2a91aa39 | 512 | int done = 0; |
2a91aa39 AB |
513 | unsigned int maxincr = 0; |
514 | ||
410e27a4 | 515 | ccid2_hc_tx_check_sanity(hctx); |
2a91aa39 AB |
516 | /* check reverse path congestion */ |
517 | seqno = DCCP_SKB_CB(skb)->dccpd_seq; | |
518 | ||
519 | /* XXX this whole "algorithm" is broken. Need to fix it to keep track | |
520 | * of the seqnos of the dupacks so that rpseq and rpdupack are correct | |
521 | * -sorbo. | |
522 | */ | |
523 | /* need to bootstrap */ | |
410e27a4 GR |
524 | if (hctx->ccid2hctx_rpdupack == -1) { |
525 | hctx->ccid2hctx_rpdupack = 0; | |
526 | hctx->ccid2hctx_rpseq = seqno; | |
c0c736db | 527 | } else { |
2a91aa39 | 528 | /* check if packet is consecutive */ |
410e27a4 GR |
529 | if (dccp_delta_seqno(hctx->ccid2hctx_rpseq, seqno) == 1) |
530 | hctx->ccid2hctx_rpseq = seqno; | |
2a91aa39 | 531 | /* it's a later packet */ |
410e27a4 GR |
532 | else if (after48(seqno, hctx->ccid2hctx_rpseq)) { |
533 | hctx->ccid2hctx_rpdupack++; | |
2a91aa39 AB |
534 | |
535 | /* check if we got enough dupacks */ | |
410e27a4 GR |
536 | if (hctx->ccid2hctx_rpdupack >= NUMDUPACK) { |
537 | hctx->ccid2hctx_rpdupack = -1; /* XXX lame */ | |
538 | hctx->ccid2hctx_rpseq = 0; | |
2a91aa39 | 539 | |
df054e1d | 540 | ccid2_change_l_ack_ratio(sk, 2 * dp->dccps_l_ack_ratio); |
2a91aa39 AB |
541 | } |
542 | } | |
543 | } | |
544 | ||
545 | /* check forward path congestion */ | |
410e27a4 GR |
546 | /* still didn't send out new data packets */ |
547 | if (hctx->ccid2hctx_seqh == hctx->ccid2hctx_seqt) | |
2a91aa39 AB |
548 | return; |
549 | ||
410e27a4 GR |
550 | switch (DCCP_SKB_CB(skb)->dccpd_type) { |
551 | case DCCP_PKT_ACK: | |
552 | case DCCP_PKT_DATAACK: | |
553 | break; | |
554 | default: | |
555 | return; | |
556 | } | |
2a91aa39 AB |
557 | |
558 | ackno = DCCP_SKB_CB(skb)->dccpd_ack_seq; | |
410e27a4 GR |
559 | if (after48(ackno, hctx->ccid2hctx_high_ack)) |
560 | hctx->ccid2hctx_high_ack = ackno; | |
32aac18d | 561 | |
410e27a4 | 562 | seqp = hctx->ccid2hctx_seqt; |
32aac18d AB |
563 | while (before48(seqp->ccid2s_seq, ackno)) { |
564 | seqp = seqp->ccid2s_next; | |
410e27a4 GR |
565 | if (seqp == hctx->ccid2hctx_seqh) { |
566 | seqp = hctx->ccid2hctx_seqh->ccid2s_prev; | |
32aac18d AB |
567 | break; |
568 | } | |
569 | } | |
2a91aa39 | 570 | |
a3020025 GR |
571 | /* |
572 | * In slow-start, cwnd can increase up to a maximum of Ack Ratio/2 | |
573 | * packets per acknowledgement. Rounding up avoids that cwnd is not | |
574 | * advanced when Ack Ratio is 1 and gives a slight edge otherwise. | |
2a91aa39 | 575 | */ |
410e27a4 | 576 | if (hctx->ccid2hctx_cwnd < hctx->ccid2hctx_ssthresh) |
a3020025 | 577 | maxincr = DIV_ROUND_UP(dp->dccps_l_ack_ratio, 2); |
2a91aa39 AB |
578 | |
579 | /* go through all ack vectors */ | |
410e27a4 GR |
580 | while ((offset = ccid2_ackvector(sk, skb, offset, |
581 | &vector, &veclen)) != -1) { | |
2a91aa39 | 582 | /* go through this ack vector */ |
410e27a4 GR |
583 | while (veclen--) { |
584 | const u8 rl = *vector & DCCP_ACKVEC_LEN_MASK; | |
585 | u64 ackno_end_rl = SUB48(ackno, rl); | |
2a91aa39 | 586 | |
410e27a4 | 587 | ccid2_pr_debug("ackvec start:%llu end:%llu\n", |
234af484 | 588 | (unsigned long long)ackno, |
410e27a4 | 589 | (unsigned long long)ackno_end_rl); |
2a91aa39 AB |
590 | /* if the seqno we are analyzing is larger than the |
591 | * current ackno, then move towards the tail of our | |
592 | * seqnos. | |
593 | */ | |
594 | while (after48(seqp->ccid2s_seq, ackno)) { | |
410e27a4 | 595 | if (seqp == hctx->ccid2hctx_seqt) { |
2a91aa39 AB |
596 | done = 1; |
597 | break; | |
598 | } | |
599 | seqp = seqp->ccid2s_prev; | |
600 | } | |
601 | if (done) | |
602 | break; | |
603 | ||
604 | /* check all seqnos in the range of the vector | |
605 | * run length | |
606 | */ | |
607 | while (between48(seqp->ccid2s_seq,ackno_end_rl,ackno)) { | |
410e27a4 GR |
608 | const u8 state = *vector & |
609 | DCCP_ACKVEC_STATE_MASK; | |
2a91aa39 AB |
610 | |
611 | /* new packet received or marked */ | |
410e27a4 | 612 | if (state != DCCP_ACKVEC_STATE_NOT_RECEIVED && |
2a91aa39 | 613 | !seqp->ccid2s_acked) { |
410e27a4 GR |
614 | if (state == |
615 | DCCP_ACKVEC_STATE_ECN_MARKED) { | |
d50ad163 | 616 | ccid2_congestion_event(sk, |
374bcf32 | 617 | seqp); |
410e27a4 | 618 | } else |
2a91aa39 AB |
619 | ccid2_new_ack(sk, seqp, |
620 | &maxincr); | |
2a91aa39 AB |
621 | |
622 | seqp->ccid2s_acked = 1; | |
623 | ccid2_pr_debug("Got ack for %llu\n", | |
234af484 | 624 | (unsigned long long)seqp->ccid2s_seq); |
410e27a4 | 625 | ccid2_hc_tx_dec_pipe(sk); |
2a91aa39 | 626 | } |
410e27a4 | 627 | if (seqp == hctx->ccid2hctx_seqt) { |
2a91aa39 AB |
628 | done = 1; |
629 | break; | |
630 | } | |
3de5489f | 631 | seqp = seqp->ccid2s_prev; |
2a91aa39 AB |
632 | } |
633 | if (done) | |
634 | break; | |
635 | ||
cfbbeabc | 636 | ackno = SUB48(ackno_end_rl, 1); |
410e27a4 | 637 | vector++; |
2a91aa39 AB |
638 | } |
639 | if (done) | |
640 | break; | |
641 | } | |
642 | ||
643 | /* The state about what is acked should be correct now | |
644 | * Check for NUMDUPACK | |
645 | */ | |
410e27a4 GR |
646 | seqp = hctx->ccid2hctx_seqt; |
647 | while (before48(seqp->ccid2s_seq, hctx->ccid2hctx_high_ack)) { | |
32aac18d | 648 | seqp = seqp->ccid2s_next; |
410e27a4 GR |
649 | if (seqp == hctx->ccid2hctx_seqh) { |
650 | seqp = hctx->ccid2hctx_seqh->ccid2s_prev; | |
32aac18d AB |
651 | break; |
652 | } | |
653 | } | |
2a91aa39 AB |
654 | done = 0; |
655 | while (1) { | |
656 | if (seqp->ccid2s_acked) { | |
657 | done++; | |
63df18ad | 658 | if (done == NUMDUPACK) |
2a91aa39 | 659 | break; |
2a91aa39 | 660 | } |
410e27a4 | 661 | if (seqp == hctx->ccid2hctx_seqt) |
2a91aa39 | 662 | break; |
2a91aa39 AB |
663 | seqp = seqp->ccid2s_prev; |
664 | } | |
665 | ||
666 | /* If there are at least 3 acknowledgements, anything unacknowledged | |
667 | * below the last sequence number is considered lost | |
668 | */ | |
63df18ad | 669 | if (done == NUMDUPACK) { |
2a91aa39 AB |
670 | struct ccid2_seq *last_acked = seqp; |
671 | ||
672 | /* check for lost packets */ | |
673 | while (1) { | |
674 | if (!seqp->ccid2s_acked) { | |
374bcf32 | 675 | ccid2_pr_debug("Packet lost: %llu\n", |
234af484 | 676 | (unsigned long long)seqp->ccid2s_seq); |
374bcf32 AB |
677 | /* XXX need to traverse from tail -> head in |
678 | * order to detect multiple congestion events in | |
679 | * one ack vector. | |
680 | */ | |
d50ad163 | 681 | ccid2_congestion_event(sk, seqp); |
410e27a4 | 682 | ccid2_hc_tx_dec_pipe(sk); |
2a91aa39 | 683 | } |
410e27a4 | 684 | if (seqp == hctx->ccid2hctx_seqt) |
2a91aa39 AB |
685 | break; |
686 | seqp = seqp->ccid2s_prev; | |
687 | } | |
688 | ||
410e27a4 | 689 | hctx->ccid2hctx_seqt = last_acked; |
2a91aa39 AB |
690 | } |
691 | ||
692 | /* trim acked packets in tail */ | |
410e27a4 GR |
693 | while (hctx->ccid2hctx_seqt != hctx->ccid2hctx_seqh) { |
694 | if (!hctx->ccid2hctx_seqt->ccid2s_acked) | |
2a91aa39 AB |
695 | break; |
696 | ||
410e27a4 | 697 | hctx->ccid2hctx_seqt = hctx->ccid2hctx_seqt->ccid2s_next; |
2a91aa39 AB |
698 | } |
699 | ||
410e27a4 | 700 | ccid2_hc_tx_check_sanity(hctx); |
2a91aa39 AB |
701 | } |
702 | ||
91f0ebf7 | 703 | static int ccid2_hc_tx_init(struct ccid *ccid, struct sock *sk) |
2a91aa39 | 704 | { |
c9eaf173 | 705 | struct ccid2_hc_tx_sock *hctx = ccid_priv(ccid); |
b00d2bbc GR |
706 | struct dccp_sock *dp = dccp_sk(sk); |
707 | u32 max_ratio; | |
2a91aa39 | 708 | |
b00d2bbc | 709 | /* RFC 4341, 5: initialise ssthresh to arbitrarily high (max) value */ |
410e27a4 | 710 | hctx->ccid2hctx_ssthresh = ~0U; |
2a91aa39 | 711 | |
410e27a4 GR |
712 | /* |
713 | * RFC 4341, 5: "The cwnd parameter is initialized to at most four | |
714 | * packets for new connections, following the rules from [RFC3390]". | |
715 | * We need to convert the bytes of RFC3390 into the packets of RFC 4341. | |
716 | */ | |
717 | hctx->ccid2hctx_cwnd = clamp(4380U / dp->dccps_mss_cache, 2U, 4U); | |
b00d2bbc GR |
718 | |
719 | /* Make sure that Ack Ratio is enabled and within bounds. */ | |
410e27a4 | 720 | max_ratio = DIV_ROUND_UP(hctx->ccid2hctx_cwnd, 2); |
b00d2bbc GR |
721 | if (dp->dccps_l_ack_ratio == 0 || dp->dccps_l_ack_ratio > max_ratio) |
722 | dp->dccps_l_ack_ratio = max_ratio; | |
723 | ||
2a91aa39 | 724 | /* XXX init ~ to window size... */ |
cd1f7d34 | 725 | if (ccid2_hc_tx_alloc_seq(hctx)) |
2a91aa39 | 726 | return -ENOMEM; |
91f0ebf7 | 727 | |
410e27a4 GR |
728 | hctx->ccid2hctx_rto = 3 * HZ; |
729 | ccid2_change_srtt(hctx, -1); | |
730 | hctx->ccid2hctx_rttvar = -1; | |
731 | hctx->ccid2hctx_rpdupack = -1; | |
732 | hctx->ccid2hctx_last_cong = jiffies; | |
733 | setup_timer(&hctx->ccid2hctx_rtotimer, ccid2_hc_tx_rto_expire, | |
734 | (unsigned long)sk); | |
735 | ||
736 | ccid2_hc_tx_check_sanity(hctx); | |
2a91aa39 AB |
737 | return 0; |
738 | } | |
739 | ||
740 | static void ccid2_hc_tx_exit(struct sock *sk) | |
741 | { | |
c9eaf173 | 742 | struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk); |
07978aab | 743 | int i; |
2a91aa39 | 744 | |
410e27a4 | 745 | ccid2_hc_tx_kill_rto_timer(sk); |
07978aab | 746 | |
410e27a4 GR |
747 | for (i = 0; i < hctx->ccid2hctx_seqbufc; i++) |
748 | kfree(hctx->ccid2hctx_seqbuf[i]); | |
749 | hctx->ccid2hctx_seqbufc = 0; | |
2a91aa39 AB |
750 | } |
751 | ||
752 | static void ccid2_hc_rx_packet_recv(struct sock *sk, struct sk_buff *skb) | |
753 | { | |
754 | const struct dccp_sock *dp = dccp_sk(sk); | |
755 | struct ccid2_hc_rx_sock *hcrx = ccid2_hc_rx_sk(sk); | |
756 | ||
757 | switch (DCCP_SKB_CB(skb)->dccpd_type) { | |
758 | case DCCP_PKT_DATA: | |
759 | case DCCP_PKT_DATAACK: | |
410e27a4 GR |
760 | hcrx->ccid2hcrx_data++; |
761 | if (hcrx->ccid2hcrx_data >= dp->dccps_r_ack_ratio) { | |
2a91aa39 | 762 | dccp_send_ack(sk); |
410e27a4 | 763 | hcrx->ccid2hcrx_data = 0; |
2a91aa39 AB |
764 | } |
765 | break; | |
766 | } | |
767 | } | |
768 | ||
ddebc973 | 769 | struct ccid_operations ccid2_ops = { |
410e27a4 GR |
770 | .ccid_id = DCCPC_CCID2, |
771 | .ccid_name = "TCP-like", | |
410e27a4 GR |
772 | .ccid_hc_tx_obj_size = sizeof(struct ccid2_hc_tx_sock), |
773 | .ccid_hc_tx_init = ccid2_hc_tx_init, | |
774 | .ccid_hc_tx_exit = ccid2_hc_tx_exit, | |
775 | .ccid_hc_tx_send_packet = ccid2_hc_tx_send_packet, | |
776 | .ccid_hc_tx_packet_sent = ccid2_hc_tx_packet_sent, | |
777 | .ccid_hc_tx_packet_recv = ccid2_hc_tx_packet_recv, | |
778 | .ccid_hc_rx_obj_size = sizeof(struct ccid2_hc_rx_sock), | |
779 | .ccid_hc_rx_packet_recv = ccid2_hc_rx_packet_recv, | |
2a91aa39 AB |
780 | }; |
781 | ||
84116716 | 782 | #ifdef CONFIG_IP_DCCP_CCID2_DEBUG |
43264991 | 783 | module_param(ccid2_debug, bool, 0644); |
ddebc973 | 784 | MODULE_PARM_DESC(ccid2_debug, "Enable CCID-2 debug messages"); |
84116716 | 785 | #endif |