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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 | */ |
5a0e3ad6 | 26 | #include <linux/slab.h> |
e8ef967a | 27 | #include "../feat.h" |
2a91aa39 AB |
28 | #include "../ccid.h" |
29 | #include "../dccp.h" | |
30 | #include "ccid2.h" | |
31 | ||
2a91aa39 | 32 | |
8d424f6c | 33 | #ifdef CONFIG_IP_DCCP_CCID2_DEBUG |
84116716 GR |
34 | static int ccid2_debug; |
35 | #define ccid2_pr_debug(format, a...) DCCP_PR_DEBUG(ccid2_debug, format, ##a) | |
410e27a4 | 36 | |
77d2dd93 | 37 | static void ccid2_hc_tx_check_sanity(const struct ccid2_hc_tx_sock *hc) |
410e27a4 GR |
38 | { |
39 | int len = 0; | |
40 | int pipe = 0; | |
77d2dd93 | 41 | struct ccid2_seq *seqp = hc->tx_seqh; |
410e27a4 GR |
42 | |
43 | /* there is data in the chain */ | |
77d2dd93 | 44 | if (seqp != hc->tx_seqt) { |
410e27a4 GR |
45 | seqp = seqp->ccid2s_prev; |
46 | len++; | |
47 | if (!seqp->ccid2s_acked) | |
48 | pipe++; | |
49 | ||
77d2dd93 | 50 | while (seqp != hc->tx_seqt) { |
410e27a4 GR |
51 | struct ccid2_seq *prev = seqp->ccid2s_prev; |
52 | ||
53 | len++; | |
54 | if (!prev->ccid2s_acked) | |
55 | pipe++; | |
56 | ||
57 | /* packets are sent sequentially */ | |
58 | BUG_ON(dccp_delta_seqno(seqp->ccid2s_seq, | |
59 | prev->ccid2s_seq ) >= 0); | |
60 | BUG_ON(time_before(seqp->ccid2s_sent, | |
61 | prev->ccid2s_sent)); | |
62 | ||
63 | seqp = prev; | |
64 | } | |
65 | } | |
66 | ||
77d2dd93 | 67 | BUG_ON(pipe != hc->tx_pipe); |
410e27a4 GR |
68 | ccid2_pr_debug("len of chain=%d\n", len); |
69 | ||
70 | do { | |
71 | seqp = seqp->ccid2s_prev; | |
72 | len++; | |
77d2dd93 | 73 | } while (seqp != hc->tx_seqh); |
410e27a4 GR |
74 | |
75 | ccid2_pr_debug("total len=%d\n", len); | |
77d2dd93 | 76 | BUG_ON(len != hc->tx_seqbufc * CCID2_SEQBUF_LEN); |
410e27a4 | 77 | } |
2a91aa39 | 78 | #else |
84116716 | 79 | #define ccid2_pr_debug(format, a...) |
77d2dd93 | 80 | #define ccid2_hc_tx_check_sanity(hc) |
2a91aa39 AB |
81 | #endif |
82 | ||
77d2dd93 | 83 | static int ccid2_hc_tx_alloc_seq(struct ccid2_hc_tx_sock *hc) |
07978aab AB |
84 | { |
85 | struct ccid2_seq *seqp; | |
86 | int i; | |
87 | ||
88 | /* check if we have space to preserve the pointer to the buffer */ | |
77d2dd93 GR |
89 | if (hc->tx_seqbufc >= (sizeof(hc->tx_seqbuf) / |
90 | sizeof(struct ccid2_seq *))) | |
07978aab AB |
91 | return -ENOMEM; |
92 | ||
93 | /* allocate buffer and initialize linked list */ | |
cd1f7d34 | 94 | seqp = kmalloc(CCID2_SEQBUF_LEN * sizeof(struct ccid2_seq), gfp_any()); |
07978aab AB |
95 | if (seqp == NULL) |
96 | return -ENOMEM; | |
97 | ||
cd1f7d34 | 98 | for (i = 0; i < (CCID2_SEQBUF_LEN - 1); i++) { |
07978aab AB |
99 | seqp[i].ccid2s_next = &seqp[i + 1]; |
100 | seqp[i + 1].ccid2s_prev = &seqp[i]; | |
101 | } | |
cd1f7d34 GR |
102 | seqp[CCID2_SEQBUF_LEN - 1].ccid2s_next = seqp; |
103 | seqp->ccid2s_prev = &seqp[CCID2_SEQBUF_LEN - 1]; | |
07978aab AB |
104 | |
105 | /* This is the first allocation. Initiate the head and tail. */ | |
77d2dd93 GR |
106 | if (hc->tx_seqbufc == 0) |
107 | hc->tx_seqh = hc->tx_seqt = seqp; | |
07978aab AB |
108 | else { |
109 | /* link the existing list with the one we just created */ | |
77d2dd93 GR |
110 | hc->tx_seqh->ccid2s_next = seqp; |
111 | seqp->ccid2s_prev = hc->tx_seqh; | |
07978aab | 112 | |
77d2dd93 GR |
113 | hc->tx_seqt->ccid2s_prev = &seqp[CCID2_SEQBUF_LEN - 1]; |
114 | seqp[CCID2_SEQBUF_LEN - 1].ccid2s_next = hc->tx_seqt; | |
07978aab AB |
115 | } |
116 | ||
117 | /* store the original pointer to the buffer so we can free it */ | |
77d2dd93 GR |
118 | hc->tx_seqbuf[hc->tx_seqbufc] = seqp; |
119 | hc->tx_seqbufc++; | |
07978aab AB |
120 | |
121 | return 0; | |
122 | } | |
123 | ||
6b57c93d | 124 | static int ccid2_hc_tx_send_packet(struct sock *sk, struct sk_buff *skb) |
2a91aa39 | 125 | { |
77d2dd93 | 126 | struct ccid2_hc_tx_sock *hc = ccid2_hc_tx_sk(sk); |
410e27a4 | 127 | |
77d2dd93 | 128 | if (hc->tx_pipe < hc->tx_cwnd) |
410e27a4 GR |
129 | return 0; |
130 | ||
131 | return 1; /* XXX CCID should dequeue when ready instead of polling */ | |
2a91aa39 AB |
132 | } |
133 | ||
df054e1d | 134 | static void ccid2_change_l_ack_ratio(struct sock *sk, u32 val) |
2a91aa39 AB |
135 | { |
136 | struct dccp_sock *dp = dccp_sk(sk); | |
b1c00fe3 | 137 | u32 max_ratio = DIV_ROUND_UP(ccid2_hc_tx_sk(sk)->tx_cwnd, 2); |
d50ad163 | 138 | |
2a91aa39 | 139 | /* |
d50ad163 GR |
140 | * Ensure that Ack Ratio does not exceed ceil(cwnd/2), which is (2) from |
141 | * RFC 4341, 6.1.2. We ignore the statement that Ack Ratio 2 is always | |
142 | * acceptable since this causes starvation/deadlock whenever cwnd < 2. | |
143 | * The same problem arises when Ack Ratio is 0 (ie. Ack Ratio disabled). | |
2a91aa39 | 144 | */ |
d50ad163 GR |
145 | if (val == 0 || val > max_ratio) { |
146 | DCCP_WARN("Limiting Ack Ratio (%u) to %u\n", val, max_ratio); | |
147 | val = max_ratio; | |
2a91aa39 | 148 | } |
e8ef967a GR |
149 | if (val > DCCPF_ACK_RATIO_MAX) |
150 | val = DCCPF_ACK_RATIO_MAX; | |
2a91aa39 | 151 | |
d50ad163 GR |
152 | if (val == dp->dccps_l_ack_ratio) |
153 | return; | |
154 | ||
df054e1d | 155 | ccid2_pr_debug("changing local ack ratio to %u\n", val); |
2a91aa39 AB |
156 | dp->dccps_l_ack_ratio = val; |
157 | } | |
158 | ||
77d2dd93 | 159 | static void ccid2_change_srtt(struct ccid2_hc_tx_sock *hc, long val) |
410e27a4 GR |
160 | { |
161 | ccid2_pr_debug("change SRTT to %ld\n", val); | |
77d2dd93 | 162 | hc->tx_srtt = val; |
410e27a4 GR |
163 | } |
164 | ||
165 | static void ccid2_start_rto_timer(struct sock *sk); | |
166 | ||
2a91aa39 AB |
167 | static void ccid2_hc_tx_rto_expire(unsigned long data) |
168 | { | |
169 | struct sock *sk = (struct sock *)data; | |
77d2dd93 | 170 | struct ccid2_hc_tx_sock *hc = ccid2_hc_tx_sk(sk); |
410e27a4 | 171 | long s; |
2a91aa39 | 172 | |
2a91aa39 AB |
173 | bh_lock_sock(sk); |
174 | if (sock_owned_by_user(sk)) { | |
77d2dd93 | 175 | sk_reset_timer(sk, &hc->tx_rtotimer, jiffies + HZ / 5); |
2a91aa39 AB |
176 | goto out; |
177 | } | |
178 | ||
179 | ccid2_pr_debug("RTO_EXPIRE\n"); | |
180 | ||
77d2dd93 | 181 | ccid2_hc_tx_check_sanity(hc); |
410e27a4 | 182 | |
2a91aa39 | 183 | /* back-off timer */ |
77d2dd93 | 184 | hc->tx_rto <<= 1; |
410e27a4 | 185 | |
77d2dd93 | 186 | s = hc->tx_rto / HZ; |
410e27a4 | 187 | if (s > 60) |
77d2dd93 | 188 | hc->tx_rto = 60 * HZ; |
410e27a4 GR |
189 | |
190 | ccid2_start_rto_timer(sk); | |
2a91aa39 | 191 | |
2a91aa39 | 192 | /* adjust pipe, cwnd etc */ |
77d2dd93 GR |
193 | hc->tx_ssthresh = hc->tx_cwnd / 2; |
194 | if (hc->tx_ssthresh < 2) | |
195 | hc->tx_ssthresh = 2; | |
196 | hc->tx_cwnd = 1; | |
197 | hc->tx_pipe = 0; | |
2a91aa39 AB |
198 | |
199 | /* clear state about stuff we sent */ | |
77d2dd93 GR |
200 | hc->tx_seqt = hc->tx_seqh; |
201 | hc->tx_packets_acked = 0; | |
2a91aa39 AB |
202 | |
203 | /* clear ack ratio state. */ | |
77d2dd93 GR |
204 | hc->tx_rpseq = 0; |
205 | hc->tx_rpdupack = -1; | |
2a91aa39 | 206 | ccid2_change_l_ack_ratio(sk, 1); |
77d2dd93 | 207 | ccid2_hc_tx_check_sanity(hc); |
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 | { | |
77d2dd93 | 215 | struct ccid2_hc_tx_sock *hc = ccid2_hc_tx_sk(sk); |
410e27a4 | 216 | |
77d2dd93 | 217 | ccid2_pr_debug("setting RTO timeout=%ld\n", hc->tx_rto); |
410e27a4 | 218 | |
77d2dd93 GR |
219 | BUG_ON(timer_pending(&hc->tx_rtotimer)); |
220 | sk_reset_timer(sk, &hc->tx_rtotimer, jiffies + hc->tx_rto); | |
410e27a4 GR |
221 | } |
222 | ||
223 | static void ccid2_hc_tx_packet_sent(struct sock *sk, int more, unsigned int len) | |
2a91aa39 AB |
224 | { |
225 | struct dccp_sock *dp = dccp_sk(sk); | |
77d2dd93 | 226 | struct ccid2_hc_tx_sock *hc = ccid2_hc_tx_sk(sk); |
07978aab | 227 | struct ccid2_seq *next; |
2a91aa39 | 228 | |
77d2dd93 | 229 | hc->tx_pipe++; |
2a91aa39 | 230 | |
77d2dd93 GR |
231 | hc->tx_seqh->ccid2s_seq = dp->dccps_gss; |
232 | hc->tx_seqh->ccid2s_acked = 0; | |
233 | hc->tx_seqh->ccid2s_sent = jiffies; | |
2a91aa39 | 234 | |
77d2dd93 | 235 | next = hc->tx_seqh->ccid2s_next; |
07978aab | 236 | /* check if we need to alloc more space */ |
77d2dd93 GR |
237 | if (next == hc->tx_seqt) { |
238 | if (ccid2_hc_tx_alloc_seq(hc)) { | |
7d9e8931 GR |
239 | DCCP_CRIT("packet history - out of memory!"); |
240 | /* FIXME: find a more graceful way to bail out */ | |
241 | return; | |
242 | } | |
77d2dd93 GR |
243 | next = hc->tx_seqh->ccid2s_next; |
244 | BUG_ON(next == hc->tx_seqt); | |
2a91aa39 | 245 | } |
77d2dd93 | 246 | hc->tx_seqh = next; |
07978aab | 247 | |
77d2dd93 | 248 | ccid2_pr_debug("cwnd=%d pipe=%d\n", hc->tx_cwnd, hc->tx_pipe); |
2a91aa39 | 249 | |
900bfed4 GR |
250 | /* |
251 | * FIXME: The code below is broken and the variables have been removed | |
252 | * from the socket struct. The `ackloss' variable was always set to 0, | |
253 | * and with arsent there are several problems: | |
254 | * (i) it doesn't just count the number of Acks, but all sent packets; | |
255 | * (ii) it is expressed in # of packets, not # of windows, so the | |
256 | * comparison below uses the wrong formula: Appendix A of RFC 4341 | |
257 | * comes up with the number K = cwnd / (R^2 - R) of consecutive windows | |
258 | * of data with no lost or marked Ack packets. If arsent were the # of | |
259 | * consecutive Acks received without loss, then Ack Ratio needs to be | |
260 | * decreased by 1 when | |
261 | * arsent >= K * cwnd / R = cwnd^2 / (R^3 - R^2) | |
262 | * where cwnd / R is the number of Acks received per window of data | |
263 | * (cf. RFC 4341, App. A). The problems are that | |
264 | * - arsent counts other packets as well; | |
265 | * - the comparison uses a formula different from RFC 4341; | |
266 | * - computing a cubic/quadratic equation each time is too complicated. | |
267 | * Hence a different algorithm is needed. | |
268 | */ | |
269 | #if 0 | |
2a91aa39 | 270 | /* Ack Ratio. Need to maintain a concept of how many windows we sent */ |
77d2dd93 | 271 | hc->tx_arsent++; |
2a91aa39 | 272 | /* We had an ack loss in this window... */ |
77d2dd93 GR |
273 | if (hc->tx_ackloss) { |
274 | if (hc->tx_arsent >= hc->tx_cwnd) { | |
275 | hc->tx_arsent = 0; | |
276 | hc->tx_ackloss = 0; | |
2a91aa39 | 277 | } |
c0c736db ACM |
278 | } else { |
279 | /* No acks lost up to now... */ | |
2a91aa39 AB |
280 | /* decrease ack ratio if enough packets were sent */ |
281 | if (dp->dccps_l_ack_ratio > 1) { | |
282 | /* XXX don't calculate denominator each time */ | |
c0c736db ACM |
283 | int denom = dp->dccps_l_ack_ratio * dp->dccps_l_ack_ratio - |
284 | dp->dccps_l_ack_ratio; | |
2a91aa39 | 285 | |
77d2dd93 | 286 | denom = hc->tx_cwnd * hc->tx_cwnd / denom; |
2a91aa39 | 287 | |
77d2dd93 | 288 | if (hc->tx_arsent >= denom) { |
2a91aa39 | 289 | ccid2_change_l_ack_ratio(sk, dp->dccps_l_ack_ratio - 1); |
77d2dd93 | 290 | hc->tx_arsent = 0; |
2a91aa39 | 291 | } |
c0c736db ACM |
292 | } else { |
293 | /* we can't increase ack ratio further [1] */ | |
77d2dd93 | 294 | hc->tx_arsent = 0; /* or maybe set it to cwnd*/ |
2a91aa39 AB |
295 | } |
296 | } | |
900bfed4 | 297 | #endif |
2a91aa39 AB |
298 | |
299 | /* setup RTO timer */ | |
77d2dd93 | 300 | if (!timer_pending(&hc->tx_rtotimer)) |
410e27a4 | 301 | ccid2_start_rto_timer(sk); |
c0c736db | 302 | |
8d424f6c | 303 | #ifdef CONFIG_IP_DCCP_CCID2_DEBUG |
2a91aa39 | 304 | do { |
77d2dd93 | 305 | struct ccid2_seq *seqp = hc->tx_seqt; |
2a91aa39 | 306 | |
77d2dd93 | 307 | while (seqp != hc->tx_seqh) { |
2a91aa39 | 308 | ccid2_pr_debug("out seq=%llu acked=%d time=%lu\n", |
8109b02b | 309 | (unsigned long long)seqp->ccid2s_seq, |
234af484 | 310 | seqp->ccid2s_acked, seqp->ccid2s_sent); |
2a91aa39 AB |
311 | seqp = seqp->ccid2s_next; |
312 | } | |
c0c736db | 313 | } while (0); |
2a91aa39 | 314 | ccid2_pr_debug("=========\n"); |
77d2dd93 | 315 | ccid2_hc_tx_check_sanity(hc); |
2a91aa39 AB |
316 | #endif |
317 | } | |
318 | ||
410e27a4 GR |
319 | /* XXX Lame code duplication! |
320 | * returns -1 if none was found. | |
321 | * else returns the next offset to use in the function call. | |
1435562d | 322 | */ |
410e27a4 GR |
323 | static int ccid2_ackvector(struct sock *sk, struct sk_buff *skb, int offset, |
324 | unsigned char **vec, unsigned char *veclen) | |
1435562d | 325 | { |
410e27a4 GR |
326 | const struct dccp_hdr *dh = dccp_hdr(skb); |
327 | unsigned char *options = (unsigned char *)dh + dccp_hdr_len(skb); | |
328 | unsigned char *opt_ptr; | |
329 | const unsigned char *opt_end = (unsigned char *)dh + | |
330 | (dh->dccph_doff * 4); | |
331 | unsigned char opt, len; | |
332 | unsigned char *value; | |
333 | ||
334 | BUG_ON(offset < 0); | |
335 | options += offset; | |
336 | opt_ptr = options; | |
337 | if (opt_ptr >= opt_end) | |
338 | return -1; | |
339 | ||
340 | while (opt_ptr != opt_end) { | |
341 | opt = *opt_ptr++; | |
342 | len = 0; | |
343 | value = NULL; | |
344 | ||
345 | /* Check if this isn't a single byte option */ | |
346 | if (opt > DCCPO_MAX_RESERVED) { | |
347 | if (opt_ptr == opt_end) | |
348 | goto out_invalid_option; | |
349 | ||
350 | len = *opt_ptr++; | |
351 | if (len < 3) | |
352 | goto out_invalid_option; | |
1435562d | 353 | /* |
410e27a4 GR |
354 | * Remove the type and len fields, leaving |
355 | * just the value size | |
1435562d | 356 | */ |
410e27a4 GR |
357 | len -= 2; |
358 | value = opt_ptr; | |
359 | opt_ptr += len; | |
1435562d | 360 | |
410e27a4 GR |
361 | if (opt_ptr > opt_end) |
362 | goto out_invalid_option; | |
1435562d GR |
363 | } |
364 | ||
410e27a4 GR |
365 | switch (opt) { |
366 | case DCCPO_ACK_VECTOR_0: | |
367 | case DCCPO_ACK_VECTOR_1: | |
368 | *vec = value; | |
369 | *veclen = len; | |
370 | return offset + (opt_ptr - options); | |
1435562d GR |
371 | } |
372 | } | |
373 | ||
410e27a4 | 374 | return -1; |
1435562d | 375 | |
410e27a4 GR |
376 | out_invalid_option: |
377 | DCCP_BUG("Invalid option - this should not happen (previous parsing)!"); | |
378 | return -1; | |
1435562d GR |
379 | } |
380 | ||
410e27a4 | 381 | static void ccid2_hc_tx_kill_rto_timer(struct sock *sk) |
2a91aa39 | 382 | { |
77d2dd93 | 383 | struct ccid2_hc_tx_sock *hc = ccid2_hc_tx_sk(sk); |
2a91aa39 | 384 | |
77d2dd93 | 385 | sk_stop_timer(sk, &hc->tx_rtotimer); |
410e27a4 | 386 | ccid2_pr_debug("deleted RTO timer\n"); |
2a91aa39 AB |
387 | } |
388 | ||
410e27a4 GR |
389 | static inline void ccid2_new_ack(struct sock *sk, |
390 | struct ccid2_seq *seqp, | |
391 | unsigned int *maxincr) | |
374bcf32 | 392 | { |
77d2dd93 | 393 | struct ccid2_hc_tx_sock *hc = ccid2_hc_tx_sk(sk); |
d50ad163 | 394 | |
77d2dd93 GR |
395 | if (hc->tx_cwnd < hc->tx_ssthresh) { |
396 | if (*maxincr > 0 && ++hc->tx_packets_acked == 2) { | |
397 | hc->tx_cwnd += 1; | |
398 | *maxincr -= 1; | |
399 | hc->tx_packets_acked = 0; | |
410e27a4 | 400 | } |
77d2dd93 GR |
401 | } else if (++hc->tx_packets_acked >= hc->tx_cwnd) { |
402 | hc->tx_cwnd += 1; | |
403 | hc->tx_packets_acked = 0; | |
374bcf32 AB |
404 | } |
405 | ||
410e27a4 | 406 | /* update RTO */ |
77d2dd93 GR |
407 | if (hc->tx_srtt == -1 || |
408 | time_after(jiffies, hc->tx_lastrtt + hc->tx_srtt)) { | |
410e27a4 GR |
409 | unsigned long r = (long)jiffies - (long)seqp->ccid2s_sent; |
410 | int s; | |
411 | ||
412 | /* first measurement */ | |
77d2dd93 | 413 | if (hc->tx_srtt == -1) { |
410e27a4 GR |
414 | ccid2_pr_debug("R: %lu Time=%lu seq=%llu\n", |
415 | r, jiffies, | |
416 | (unsigned long long)seqp->ccid2s_seq); | |
77d2dd93 GR |
417 | ccid2_change_srtt(hc, r); |
418 | hc->tx_rttvar = r >> 1; | |
410e27a4 GR |
419 | } else { |
420 | /* RTTVAR */ | |
77d2dd93 | 421 | long tmp = hc->tx_srtt - r; |
410e27a4 GR |
422 | long srtt; |
423 | ||
424 | if (tmp < 0) | |
425 | tmp *= -1; | |
426 | ||
427 | tmp >>= 2; | |
77d2dd93 GR |
428 | hc->tx_rttvar *= 3; |
429 | hc->tx_rttvar >>= 2; | |
430 | hc->tx_rttvar += tmp; | |
410e27a4 GR |
431 | |
432 | /* SRTT */ | |
77d2dd93 | 433 | srtt = hc->tx_srtt; |
410e27a4 GR |
434 | srtt *= 7; |
435 | srtt >>= 3; | |
436 | tmp = r >> 3; | |
437 | srtt += tmp; | |
77d2dd93 | 438 | ccid2_change_srtt(hc, srtt); |
410e27a4 | 439 | } |
77d2dd93 | 440 | s = hc->tx_rttvar << 2; |
410e27a4 GR |
441 | /* clock granularity is 1 when based on jiffies */ |
442 | if (!s) | |
443 | s = 1; | |
77d2dd93 | 444 | hc->tx_rto = hc->tx_srtt + s; |
410e27a4 GR |
445 | |
446 | /* must be at least a second */ | |
77d2dd93 | 447 | s = hc->tx_rto / HZ; |
410e27a4 GR |
448 | /* DCCP doesn't require this [but I like it cuz my code sux] */ |
449 | #if 1 | |
450 | if (s < 1) | |
77d2dd93 | 451 | hc->tx_rto = HZ; |
410e27a4 GR |
452 | #endif |
453 | /* max 60 seconds */ | |
454 | if (s > 60) | |
77d2dd93 | 455 | hc->tx_rto = HZ * 60; |
374bcf32 | 456 | |
77d2dd93 | 457 | hc->tx_lastrtt = jiffies; |
d50ad163 | 458 | |
410e27a4 | 459 | ccid2_pr_debug("srtt: %ld rttvar: %ld rto: %ld (HZ=%d) R=%lu\n", |
77d2dd93 GR |
460 | hc->tx_srtt, hc->tx_rttvar, |
461 | hc->tx_rto, HZ, r); | |
410e27a4 GR |
462 | } |
463 | ||
464 | /* we got a new ack, so re-start RTO timer */ | |
465 | ccid2_hc_tx_kill_rto_timer(sk); | |
466 | ccid2_start_rto_timer(sk); | |
374bcf32 AB |
467 | } |
468 | ||
410e27a4 | 469 | static void ccid2_hc_tx_dec_pipe(struct sock *sk) |
c8bf462b | 470 | { |
77d2dd93 | 471 | struct ccid2_hc_tx_sock *hc = ccid2_hc_tx_sk(sk); |
c8bf462b | 472 | |
77d2dd93 | 473 | if (hc->tx_pipe == 0) |
410e27a4 GR |
474 | DCCP_BUG("pipe == 0"); |
475 | else | |
77d2dd93 | 476 | hc->tx_pipe--; |
410e27a4 | 477 | |
77d2dd93 | 478 | if (hc->tx_pipe == 0) |
410e27a4 GR |
479 | ccid2_hc_tx_kill_rto_timer(sk); |
480 | } | |
481 | ||
482 | static void ccid2_congestion_event(struct sock *sk, struct ccid2_seq *seqp) | |
483 | { | |
77d2dd93 | 484 | struct ccid2_hc_tx_sock *hc = ccid2_hc_tx_sk(sk); |
410e27a4 | 485 | |
77d2dd93 | 486 | if (time_before(seqp->ccid2s_sent, hc->tx_last_cong)) { |
410e27a4 GR |
487 | ccid2_pr_debug("Multiple losses in an RTT---treating as one\n"); |
488 | return; | |
c8bf462b | 489 | } |
410e27a4 | 490 | |
77d2dd93 | 491 | hc->tx_last_cong = jiffies; |
410e27a4 | 492 | |
77d2dd93 GR |
493 | hc->tx_cwnd = hc->tx_cwnd / 2 ? : 1U; |
494 | hc->tx_ssthresh = max(hc->tx_cwnd, 2U); | |
410e27a4 GR |
495 | |
496 | /* Avoid spurious timeouts resulting from Ack Ratio > cwnd */ | |
77d2dd93 GR |
497 | if (dccp_sk(sk)->dccps_l_ack_ratio > hc->tx_cwnd) |
498 | ccid2_change_l_ack_ratio(sk, hc->tx_cwnd); | |
c8bf462b GR |
499 | } |
500 | ||
2a91aa39 AB |
501 | static void ccid2_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb) |
502 | { | |
503 | struct dccp_sock *dp = dccp_sk(sk); | |
77d2dd93 | 504 | struct ccid2_hc_tx_sock *hc = ccid2_hc_tx_sk(sk); |
2a91aa39 AB |
505 | u64 ackno, seqno; |
506 | struct ccid2_seq *seqp; | |
410e27a4 GR |
507 | unsigned char *vector; |
508 | unsigned char veclen; | |
509 | int offset = 0; | |
2a91aa39 | 510 | int done = 0; |
2a91aa39 AB |
511 | unsigned int maxincr = 0; |
512 | ||
77d2dd93 | 513 | ccid2_hc_tx_check_sanity(hc); |
2a91aa39 AB |
514 | /* check reverse path congestion */ |
515 | seqno = DCCP_SKB_CB(skb)->dccpd_seq; | |
516 | ||
517 | /* XXX this whole "algorithm" is broken. Need to fix it to keep track | |
518 | * of the seqnos of the dupacks so that rpseq and rpdupack are correct | |
519 | * -sorbo. | |
520 | */ | |
521 | /* need to bootstrap */ | |
77d2dd93 GR |
522 | if (hc->tx_rpdupack == -1) { |
523 | hc->tx_rpdupack = 0; | |
524 | hc->tx_rpseq = seqno; | |
c0c736db | 525 | } else { |
2a91aa39 | 526 | /* check if packet is consecutive */ |
77d2dd93 GR |
527 | if (dccp_delta_seqno(hc->tx_rpseq, seqno) == 1) |
528 | hc->tx_rpseq = seqno; | |
2a91aa39 | 529 | /* it's a later packet */ |
77d2dd93 GR |
530 | else if (after48(seqno, hc->tx_rpseq)) { |
531 | hc->tx_rpdupack++; | |
2a91aa39 AB |
532 | |
533 | /* check if we got enough dupacks */ | |
77d2dd93 GR |
534 | if (hc->tx_rpdupack >= NUMDUPACK) { |
535 | hc->tx_rpdupack = -1; /* XXX lame */ | |
536 | hc->tx_rpseq = 0; | |
2a91aa39 | 537 | |
df054e1d | 538 | ccid2_change_l_ack_ratio(sk, 2 * dp->dccps_l_ack_ratio); |
2a91aa39 AB |
539 | } |
540 | } | |
541 | } | |
542 | ||
543 | /* check forward path congestion */ | |
410e27a4 | 544 | /* still didn't send out new data packets */ |
77d2dd93 | 545 | if (hc->tx_seqh == hc->tx_seqt) |
2a91aa39 AB |
546 | return; |
547 | ||
410e27a4 GR |
548 | switch (DCCP_SKB_CB(skb)->dccpd_type) { |
549 | case DCCP_PKT_ACK: | |
550 | case DCCP_PKT_DATAACK: | |
551 | break; | |
552 | default: | |
553 | return; | |
554 | } | |
2a91aa39 AB |
555 | |
556 | ackno = DCCP_SKB_CB(skb)->dccpd_ack_seq; | |
77d2dd93 GR |
557 | if (after48(ackno, hc->tx_high_ack)) |
558 | hc->tx_high_ack = ackno; | |
32aac18d | 559 | |
77d2dd93 | 560 | seqp = hc->tx_seqt; |
32aac18d AB |
561 | while (before48(seqp->ccid2s_seq, ackno)) { |
562 | seqp = seqp->ccid2s_next; | |
77d2dd93 GR |
563 | if (seqp == hc->tx_seqh) { |
564 | seqp = hc->tx_seqh->ccid2s_prev; | |
32aac18d AB |
565 | break; |
566 | } | |
567 | } | |
2a91aa39 | 568 | |
a3020025 GR |
569 | /* |
570 | * In slow-start, cwnd can increase up to a maximum of Ack Ratio/2 | |
571 | * packets per acknowledgement. Rounding up avoids that cwnd is not | |
572 | * advanced when Ack Ratio is 1 and gives a slight edge otherwise. | |
2a91aa39 | 573 | */ |
77d2dd93 | 574 | if (hc->tx_cwnd < hc->tx_ssthresh) |
a3020025 | 575 | maxincr = DIV_ROUND_UP(dp->dccps_l_ack_ratio, 2); |
2a91aa39 AB |
576 | |
577 | /* go through all ack vectors */ | |
410e27a4 GR |
578 | while ((offset = ccid2_ackvector(sk, skb, offset, |
579 | &vector, &veclen)) != -1) { | |
2a91aa39 | 580 | /* go through this ack vector */ |
410e27a4 GR |
581 | while (veclen--) { |
582 | const u8 rl = *vector & DCCP_ACKVEC_LEN_MASK; | |
583 | u64 ackno_end_rl = SUB48(ackno, rl); | |
2a91aa39 | 584 | |
410e27a4 | 585 | ccid2_pr_debug("ackvec start:%llu end:%llu\n", |
234af484 | 586 | (unsigned long long)ackno, |
410e27a4 | 587 | (unsigned long long)ackno_end_rl); |
2a91aa39 AB |
588 | /* if the seqno we are analyzing is larger than the |
589 | * current ackno, then move towards the tail of our | |
590 | * seqnos. | |
591 | */ | |
592 | while (after48(seqp->ccid2s_seq, ackno)) { | |
77d2dd93 | 593 | if (seqp == hc->tx_seqt) { |
2a91aa39 AB |
594 | done = 1; |
595 | break; | |
596 | } | |
597 | seqp = seqp->ccid2s_prev; | |
598 | } | |
599 | if (done) | |
600 | break; | |
601 | ||
602 | /* check all seqnos in the range of the vector | |
603 | * run length | |
604 | */ | |
605 | while (between48(seqp->ccid2s_seq,ackno_end_rl,ackno)) { | |
410e27a4 GR |
606 | const u8 state = *vector & |
607 | DCCP_ACKVEC_STATE_MASK; | |
2a91aa39 AB |
608 | |
609 | /* new packet received or marked */ | |
410e27a4 | 610 | if (state != DCCP_ACKVEC_STATE_NOT_RECEIVED && |
2a91aa39 | 611 | !seqp->ccid2s_acked) { |
410e27a4 GR |
612 | if (state == |
613 | DCCP_ACKVEC_STATE_ECN_MARKED) { | |
d50ad163 | 614 | ccid2_congestion_event(sk, |
374bcf32 | 615 | seqp); |
410e27a4 | 616 | } else |
2a91aa39 AB |
617 | ccid2_new_ack(sk, seqp, |
618 | &maxincr); | |
2a91aa39 AB |
619 | |
620 | seqp->ccid2s_acked = 1; | |
621 | ccid2_pr_debug("Got ack for %llu\n", | |
234af484 | 622 | (unsigned long long)seqp->ccid2s_seq); |
410e27a4 | 623 | ccid2_hc_tx_dec_pipe(sk); |
2a91aa39 | 624 | } |
77d2dd93 | 625 | if (seqp == hc->tx_seqt) { |
2a91aa39 AB |
626 | done = 1; |
627 | break; | |
628 | } | |
3de5489f | 629 | seqp = seqp->ccid2s_prev; |
2a91aa39 AB |
630 | } |
631 | if (done) | |
632 | break; | |
633 | ||
cfbbeabc | 634 | ackno = SUB48(ackno_end_rl, 1); |
410e27a4 | 635 | vector++; |
2a91aa39 AB |
636 | } |
637 | if (done) | |
638 | break; | |
639 | } | |
640 | ||
641 | /* The state about what is acked should be correct now | |
642 | * Check for NUMDUPACK | |
643 | */ | |
77d2dd93 GR |
644 | seqp = hc->tx_seqt; |
645 | while (before48(seqp->ccid2s_seq, hc->tx_high_ack)) { | |
32aac18d | 646 | seqp = seqp->ccid2s_next; |
77d2dd93 GR |
647 | if (seqp == hc->tx_seqh) { |
648 | seqp = hc->tx_seqh->ccid2s_prev; | |
32aac18d AB |
649 | break; |
650 | } | |
651 | } | |
2a91aa39 AB |
652 | done = 0; |
653 | while (1) { | |
654 | if (seqp->ccid2s_acked) { | |
655 | done++; | |
63df18ad | 656 | if (done == NUMDUPACK) |
2a91aa39 | 657 | break; |
2a91aa39 | 658 | } |
77d2dd93 | 659 | if (seqp == hc->tx_seqt) |
2a91aa39 | 660 | break; |
2a91aa39 AB |
661 | seqp = seqp->ccid2s_prev; |
662 | } | |
663 | ||
664 | /* If there are at least 3 acknowledgements, anything unacknowledged | |
665 | * below the last sequence number is considered lost | |
666 | */ | |
63df18ad | 667 | if (done == NUMDUPACK) { |
2a91aa39 AB |
668 | struct ccid2_seq *last_acked = seqp; |
669 | ||
670 | /* check for lost packets */ | |
671 | while (1) { | |
672 | if (!seqp->ccid2s_acked) { | |
374bcf32 | 673 | ccid2_pr_debug("Packet lost: %llu\n", |
234af484 | 674 | (unsigned long long)seqp->ccid2s_seq); |
374bcf32 AB |
675 | /* XXX need to traverse from tail -> head in |
676 | * order to detect multiple congestion events in | |
677 | * one ack vector. | |
678 | */ | |
d50ad163 | 679 | ccid2_congestion_event(sk, seqp); |
410e27a4 | 680 | ccid2_hc_tx_dec_pipe(sk); |
2a91aa39 | 681 | } |
77d2dd93 | 682 | if (seqp == hc->tx_seqt) |
2a91aa39 AB |
683 | break; |
684 | seqp = seqp->ccid2s_prev; | |
685 | } | |
686 | ||
77d2dd93 | 687 | hc->tx_seqt = last_acked; |
2a91aa39 AB |
688 | } |
689 | ||
690 | /* trim acked packets in tail */ | |
77d2dd93 GR |
691 | while (hc->tx_seqt != hc->tx_seqh) { |
692 | if (!hc->tx_seqt->ccid2s_acked) | |
2a91aa39 AB |
693 | break; |
694 | ||
77d2dd93 | 695 | hc->tx_seqt = hc->tx_seqt->ccid2s_next; |
2a91aa39 AB |
696 | } |
697 | ||
77d2dd93 | 698 | ccid2_hc_tx_check_sanity(hc); |
2a91aa39 AB |
699 | } |
700 | ||
91f0ebf7 | 701 | static int ccid2_hc_tx_init(struct ccid *ccid, struct sock *sk) |
2a91aa39 | 702 | { |
77d2dd93 | 703 | struct ccid2_hc_tx_sock *hc = ccid_priv(ccid); |
b00d2bbc GR |
704 | struct dccp_sock *dp = dccp_sk(sk); |
705 | u32 max_ratio; | |
2a91aa39 | 706 | |
b00d2bbc | 707 | /* RFC 4341, 5: initialise ssthresh to arbitrarily high (max) value */ |
77d2dd93 | 708 | hc->tx_ssthresh = ~0U; |
2a91aa39 | 709 | |
410e27a4 GR |
710 | /* |
711 | * RFC 4341, 5: "The cwnd parameter is initialized to at most four | |
712 | * packets for new connections, following the rules from [RFC3390]". | |
713 | * We need to convert the bytes of RFC3390 into the packets of RFC 4341. | |
714 | */ | |
77d2dd93 | 715 | hc->tx_cwnd = clamp(4380U / dp->dccps_mss_cache, 2U, 4U); |
b00d2bbc GR |
716 | |
717 | /* Make sure that Ack Ratio is enabled and within bounds. */ | |
77d2dd93 | 718 | max_ratio = DIV_ROUND_UP(hc->tx_cwnd, 2); |
b00d2bbc GR |
719 | if (dp->dccps_l_ack_ratio == 0 || dp->dccps_l_ack_ratio > max_ratio) |
720 | dp->dccps_l_ack_ratio = max_ratio; | |
721 | ||
2a91aa39 | 722 | /* XXX init ~ to window size... */ |
77d2dd93 | 723 | if (ccid2_hc_tx_alloc_seq(hc)) |
2a91aa39 | 724 | return -ENOMEM; |
91f0ebf7 | 725 | |
77d2dd93 GR |
726 | hc->tx_rto = 3 * HZ; |
727 | ccid2_change_srtt(hc, -1); | |
728 | hc->tx_rttvar = -1; | |
729 | hc->tx_rpdupack = -1; | |
730 | hc->tx_last_cong = jiffies; | |
731 | setup_timer(&hc->tx_rtotimer, ccid2_hc_tx_rto_expire, | |
410e27a4 GR |
732 | (unsigned long)sk); |
733 | ||
77d2dd93 | 734 | ccid2_hc_tx_check_sanity(hc); |
2a91aa39 AB |
735 | return 0; |
736 | } | |
737 | ||
738 | static void ccid2_hc_tx_exit(struct sock *sk) | |
739 | { | |
77d2dd93 | 740 | struct ccid2_hc_tx_sock *hc = ccid2_hc_tx_sk(sk); |
07978aab | 741 | int i; |
2a91aa39 | 742 | |
410e27a4 | 743 | ccid2_hc_tx_kill_rto_timer(sk); |
07978aab | 744 | |
77d2dd93 GR |
745 | for (i = 0; i < hc->tx_seqbufc; i++) |
746 | kfree(hc->tx_seqbuf[i]); | |
747 | hc->tx_seqbufc = 0; | |
2a91aa39 AB |
748 | } |
749 | ||
750 | static void ccid2_hc_rx_packet_recv(struct sock *sk, struct sk_buff *skb) | |
751 | { | |
752 | const struct dccp_sock *dp = dccp_sk(sk); | |
77d2dd93 | 753 | struct ccid2_hc_rx_sock *hc = ccid2_hc_rx_sk(sk); |
2a91aa39 AB |
754 | |
755 | switch (DCCP_SKB_CB(skb)->dccpd_type) { | |
756 | case DCCP_PKT_DATA: | |
757 | case DCCP_PKT_DATAACK: | |
77d2dd93 GR |
758 | hc->rx_data++; |
759 | if (hc->rx_data >= dp->dccps_r_ack_ratio) { | |
2a91aa39 | 760 | dccp_send_ack(sk); |
77d2dd93 | 761 | hc->rx_data = 0; |
2a91aa39 AB |
762 | } |
763 | break; | |
764 | } | |
765 | } | |
766 | ||
ddebc973 | 767 | struct ccid_operations ccid2_ops = { |
410e27a4 GR |
768 | .ccid_id = DCCPC_CCID2, |
769 | .ccid_name = "TCP-like", | |
410e27a4 GR |
770 | .ccid_hc_tx_obj_size = sizeof(struct ccid2_hc_tx_sock), |
771 | .ccid_hc_tx_init = ccid2_hc_tx_init, | |
772 | .ccid_hc_tx_exit = ccid2_hc_tx_exit, | |
773 | .ccid_hc_tx_send_packet = ccid2_hc_tx_send_packet, | |
774 | .ccid_hc_tx_packet_sent = ccid2_hc_tx_packet_sent, | |
775 | .ccid_hc_tx_packet_recv = ccid2_hc_tx_packet_recv, | |
776 | .ccid_hc_rx_obj_size = sizeof(struct ccid2_hc_rx_sock), | |
777 | .ccid_hc_rx_packet_recv = ccid2_hc_rx_packet_recv, | |
2a91aa39 AB |
778 | }; |
779 | ||
84116716 | 780 | #ifdef CONFIG_IP_DCCP_CCID2_DEBUG |
43264991 | 781 | module_param(ccid2_debug, bool, 0644); |
ddebc973 | 782 | MODULE_PARM_DESC(ccid2_debug, "Enable CCID-2 debug messages"); |
84116716 | 783 | #endif |