1 // SPDX-License-Identifier: GPL-2.0-or-later 1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /* 2 /*
3 * Copyright (c) 2005, 2006 Andrea Bittau <a. 3 * Copyright (c) 2005, 2006 Andrea Bittau <a.bittau@cs.ucl.ac.uk>
4 * 4 *
5 * Changes to meet Linux coding standards, an 5 * Changes to meet Linux coding standards, and DCCP infrastructure fixes.
6 * 6 *
7 * Copyright (c) 2006 Arnaldo Carvalho de Mel 7 * Copyright (c) 2006 Arnaldo Carvalho de Melo <acme@conectiva.com.br>
8 */ 8 */
9 9
10 /* 10 /*
11 * This implementation should follow RFC 4341 11 * This implementation should follow RFC 4341
12 */ 12 */
13 #include <linux/slab.h> 13 #include <linux/slab.h>
14 #include "../feat.h" 14 #include "../feat.h"
15 #include "ccid2.h" 15 #include "ccid2.h"
16 16
17 17
18 #ifdef CONFIG_IP_DCCP_CCID2_DEBUG 18 #ifdef CONFIG_IP_DCCP_CCID2_DEBUG
19 static bool ccid2_debug; 19 static bool ccid2_debug;
20 #define ccid2_pr_debug(format, a...) DCCP_P 20 #define ccid2_pr_debug(format, a...) DCCP_PR_DEBUG(ccid2_debug, format, ##a)
21 #else 21 #else
22 #define ccid2_pr_debug(format, a...) 22 #define ccid2_pr_debug(format, a...)
23 #endif 23 #endif
24 24
25 static int ccid2_hc_tx_alloc_seq(struct ccid2_ 25 static int ccid2_hc_tx_alloc_seq(struct ccid2_hc_tx_sock *hc)
26 { 26 {
27 struct ccid2_seq *seqp; 27 struct ccid2_seq *seqp;
28 int i; 28 int i;
29 29
30 /* check if we have space to preserve 30 /* check if we have space to preserve the pointer to the buffer */
31 if (hc->tx_seqbufc >= (sizeof(hc->tx_s 31 if (hc->tx_seqbufc >= (sizeof(hc->tx_seqbuf) /
32 sizeof(struct c 32 sizeof(struct ccid2_seq *)))
33 return -ENOMEM; 33 return -ENOMEM;
34 34
35 /* allocate buffer and initialize link 35 /* allocate buffer and initialize linked list */
36 seqp = kmalloc_array(CCID2_SEQBUF_LEN, 36 seqp = kmalloc_array(CCID2_SEQBUF_LEN, sizeof(struct ccid2_seq),
37 gfp_any()); 37 gfp_any());
38 if (seqp == NULL) 38 if (seqp == NULL)
39 return -ENOMEM; 39 return -ENOMEM;
40 40
41 for (i = 0; i < (CCID2_SEQBUF_LEN - 1) 41 for (i = 0; i < (CCID2_SEQBUF_LEN - 1); i++) {
42 seqp[i].ccid2s_next = &seqp[i 42 seqp[i].ccid2s_next = &seqp[i + 1];
43 seqp[i + 1].ccid2s_prev = &seq 43 seqp[i + 1].ccid2s_prev = &seqp[i];
44 } 44 }
45 seqp[CCID2_SEQBUF_LEN - 1].ccid2s_next 45 seqp[CCID2_SEQBUF_LEN - 1].ccid2s_next = seqp;
46 seqp->ccid2s_prev = &seqp[CCID2_SEQBUF 46 seqp->ccid2s_prev = &seqp[CCID2_SEQBUF_LEN - 1];
47 47
48 /* This is the first allocation. Init 48 /* This is the first allocation. Initiate the head and tail. */
49 if (hc->tx_seqbufc == 0) 49 if (hc->tx_seqbufc == 0)
50 hc->tx_seqh = hc->tx_seqt = se 50 hc->tx_seqh = hc->tx_seqt = seqp;
51 else { 51 else {
52 /* link the existing list with 52 /* link the existing list with the one we just created */
53 hc->tx_seqh->ccid2s_next = seq 53 hc->tx_seqh->ccid2s_next = seqp;
54 seqp->ccid2s_prev = hc->tx_seq 54 seqp->ccid2s_prev = hc->tx_seqh;
55 55
56 hc->tx_seqt->ccid2s_prev = &se 56 hc->tx_seqt->ccid2s_prev = &seqp[CCID2_SEQBUF_LEN - 1];
57 seqp[CCID2_SEQBUF_LEN - 1].cci 57 seqp[CCID2_SEQBUF_LEN - 1].ccid2s_next = hc->tx_seqt;
58 } 58 }
59 59
60 /* store the original pointer to the b 60 /* store the original pointer to the buffer so we can free it */
61 hc->tx_seqbuf[hc->tx_seqbufc] = seqp; 61 hc->tx_seqbuf[hc->tx_seqbufc] = seqp;
62 hc->tx_seqbufc++; 62 hc->tx_seqbufc++;
63 63
64 return 0; 64 return 0;
65 } 65 }
66 66
67 static int ccid2_hc_tx_send_packet(struct sock 67 static int ccid2_hc_tx_send_packet(struct sock *sk, struct sk_buff *skb)
68 { 68 {
69 if (ccid2_cwnd_network_limited(ccid2_h 69 if (ccid2_cwnd_network_limited(ccid2_hc_tx_sk(sk)))
70 return CCID_PACKET_WILL_DEQUEU 70 return CCID_PACKET_WILL_DEQUEUE_LATER;
71 return CCID_PACKET_SEND_AT_ONCE; 71 return CCID_PACKET_SEND_AT_ONCE;
72 } 72 }
73 73
74 static void ccid2_change_l_ack_ratio(struct so 74 static void ccid2_change_l_ack_ratio(struct sock *sk, u32 val)
75 { 75 {
76 u32 max_ratio = DIV_ROUND_UP(ccid2_hc_ 76 u32 max_ratio = DIV_ROUND_UP(ccid2_hc_tx_sk(sk)->tx_cwnd, 2);
77 77
78 /* 78 /*
79 * Ensure that Ack Ratio does not exce 79 * Ensure that Ack Ratio does not exceed ceil(cwnd/2), which is (2) from
80 * RFC 4341, 6.1.2. We ignore the stat 80 * RFC 4341, 6.1.2. We ignore the statement that Ack Ratio 2 is always
81 * acceptable since this causes starva 81 * acceptable since this causes starvation/deadlock whenever cwnd < 2.
82 * The same problem arises when Ack Ra 82 * The same problem arises when Ack Ratio is 0 (ie. Ack Ratio disabled).
83 */ 83 */
84 if (val == 0 || val > max_ratio) { 84 if (val == 0 || val > max_ratio) {
85 DCCP_WARN("Limiting Ack Ratio 85 DCCP_WARN("Limiting Ack Ratio (%u) to %u\n", val, max_ratio);
86 val = max_ratio; 86 val = max_ratio;
87 } 87 }
88 dccp_feat_signal_nn_change(sk, DCCPF_A 88 dccp_feat_signal_nn_change(sk, DCCPF_ACK_RATIO,
89 min_t(u32, 89 min_t(u32, val, DCCPF_ACK_RATIO_MAX));
90 } 90 }
91 91
92 static void ccid2_check_l_ack_ratio(struct soc 92 static void ccid2_check_l_ack_ratio(struct sock *sk)
93 { 93 {
94 struct ccid2_hc_tx_sock *hc = ccid2_hc 94 struct ccid2_hc_tx_sock *hc = ccid2_hc_tx_sk(sk);
95 95
96 /* 96 /*
97 * After a loss, idle period, applicat 97 * After a loss, idle period, application limited period, or RTO we
98 * need to check that the ack ratio is 98 * need to check that the ack ratio is still less than the congestion
99 * window. Otherwise, we will send an 99 * window. Otherwise, we will send an entire congestion window of
100 * packets and got no response because 100 * packets and got no response because we haven't sent ack ratio
101 * packets yet. 101 * packets yet.
102 * If the ack ratio does need to be re 102 * If the ack ratio does need to be reduced, we reduce it to half of
103 * the congestion window (or 1 if that 103 * the congestion window (or 1 if that's zero) instead of to the
104 * congestion window. This prevents pr 104 * congestion window. This prevents problems if one ack is lost.
105 */ 105 */
106 if (dccp_feat_nn_get(sk, DCCPF_ACK_RAT 106 if (dccp_feat_nn_get(sk, DCCPF_ACK_RATIO) > hc->tx_cwnd)
107 ccid2_change_l_ack_ratio(sk, h 107 ccid2_change_l_ack_ratio(sk, hc->tx_cwnd/2 ? : 1U);
108 } 108 }
109 109
110 static void ccid2_change_l_seq_window(struct s 110 static void ccid2_change_l_seq_window(struct sock *sk, u64 val)
111 { 111 {
112 dccp_feat_signal_nn_change(sk, DCCPF_S 112 dccp_feat_signal_nn_change(sk, DCCPF_SEQUENCE_WINDOW,
113 clamp_val(v 113 clamp_val(val, DCCPF_SEQ_WMIN,
114 114 DCCPF_SEQ_WMAX));
115 } 115 }
116 116
117 static void dccp_tasklet_schedule(struct sock 117 static void dccp_tasklet_schedule(struct sock *sk)
118 { 118 {
119 struct tasklet_struct *t = &dccp_sk(sk 119 struct tasklet_struct *t = &dccp_sk(sk)->dccps_xmitlet;
120 120
121 if (!test_and_set_bit(TASKLET_STATE_SC 121 if (!test_and_set_bit(TASKLET_STATE_SCHED, &t->state)) {
122 sock_hold(sk); 122 sock_hold(sk);
123 __tasklet_schedule(t); 123 __tasklet_schedule(t);
124 } 124 }
125 } 125 }
126 126
127 static void ccid2_hc_tx_rto_expire(struct time 127 static void ccid2_hc_tx_rto_expire(struct timer_list *t)
128 { 128 {
129 struct ccid2_hc_tx_sock *hc = from_tim 129 struct ccid2_hc_tx_sock *hc = from_timer(hc, t, tx_rtotimer);
130 struct sock *sk = hc->sk; 130 struct sock *sk = hc->sk;
131 const bool sender_was_blocked = ccid2_ 131 const bool sender_was_blocked = ccid2_cwnd_network_limited(hc);
132 132
133 bh_lock_sock(sk); 133 bh_lock_sock(sk);
134 if (sock_owned_by_user(sk)) { 134 if (sock_owned_by_user(sk)) {
135 sk_reset_timer(sk, &hc->tx_rto 135 sk_reset_timer(sk, &hc->tx_rtotimer, jiffies + HZ / 5);
136 goto out; 136 goto out;
137 } 137 }
138 138
139 ccid2_pr_debug("RTO_EXPIRE\n"); 139 ccid2_pr_debug("RTO_EXPIRE\n");
140 140
141 if (sk->sk_state == DCCP_CLOSED) 141 if (sk->sk_state == DCCP_CLOSED)
142 goto out; 142 goto out;
143 143
144 /* back-off timer */ 144 /* back-off timer */
145 hc->tx_rto <<= 1; 145 hc->tx_rto <<= 1;
146 if (hc->tx_rto > DCCP_RTO_MAX) 146 if (hc->tx_rto > DCCP_RTO_MAX)
147 hc->tx_rto = DCCP_RTO_MAX; 147 hc->tx_rto = DCCP_RTO_MAX;
148 148
149 /* adjust pipe, cwnd etc */ 149 /* adjust pipe, cwnd etc */
150 hc->tx_ssthresh = hc->tx_cwnd / 2; 150 hc->tx_ssthresh = hc->tx_cwnd / 2;
151 if (hc->tx_ssthresh < 2) 151 if (hc->tx_ssthresh < 2)
152 hc->tx_ssthresh = 2; 152 hc->tx_ssthresh = 2;
153 hc->tx_cwnd = 1; 153 hc->tx_cwnd = 1;
154 hc->tx_pipe = 0; 154 hc->tx_pipe = 0;
155 155
156 /* clear state about stuff we sent */ 156 /* clear state about stuff we sent */
157 hc->tx_seqt = hc->tx_seqh; 157 hc->tx_seqt = hc->tx_seqh;
158 hc->tx_packets_acked = 0; 158 hc->tx_packets_acked = 0;
159 159
160 /* clear ack ratio state. */ 160 /* clear ack ratio state. */
161 hc->tx_rpseq = 0; 161 hc->tx_rpseq = 0;
162 hc->tx_rpdupack = -1; 162 hc->tx_rpdupack = -1;
163 ccid2_change_l_ack_ratio(sk, 1); 163 ccid2_change_l_ack_ratio(sk, 1);
164 164
165 /* if we were blocked before, we may n 165 /* if we were blocked before, we may now send cwnd=1 packet */
166 if (sender_was_blocked) 166 if (sender_was_blocked)
167 dccp_tasklet_schedule(sk); 167 dccp_tasklet_schedule(sk);
168 /* restart backed-off timer */ 168 /* restart backed-off timer */
169 sk_reset_timer(sk, &hc->tx_rtotimer, j 169 sk_reset_timer(sk, &hc->tx_rtotimer, jiffies + hc->tx_rto);
170 out: 170 out:
171 bh_unlock_sock(sk); 171 bh_unlock_sock(sk);
172 sock_put(sk); 172 sock_put(sk);
173 } 173 }
174 174
175 /* 175 /*
176 * Congestion window validation (RFC 2861 176 * Congestion window validation (RFC 2861).
177 */ 177 */
178 static bool ccid2_do_cwv = true; 178 static bool ccid2_do_cwv = true;
179 module_param(ccid2_do_cwv, bool, 0644); 179 module_param(ccid2_do_cwv, bool, 0644);
180 MODULE_PARM_DESC(ccid2_do_cwv, "Perform RFC286 180 MODULE_PARM_DESC(ccid2_do_cwv, "Perform RFC2861 Congestion Window Validation");
181 181
182 /** 182 /**
183 * ccid2_update_used_window - Track how much 183 * ccid2_update_used_window - Track how much of cwnd is actually used
184 * @hc: socket to update window <<
185 * @new_wnd: new window values to add into the <<
186 * <<
187 * This is done in addition to CWV. The sender 184 * This is done in addition to CWV. The sender needs to have an idea of how many
188 * packets may be in flight, to set the local 185 * packets may be in flight, to set the local Sequence Window value accordingly
189 * (RFC 4340, 7.5.2). The CWV mechanism is exp 186 * (RFC 4340, 7.5.2). The CWV mechanism is exploited to keep track of the
190 * maximum-used window. We use an EWMA low-pas 187 * maximum-used window. We use an EWMA low-pass filter to filter out noise.
191 */ 188 */
192 static void ccid2_update_used_window(struct cc 189 static void ccid2_update_used_window(struct ccid2_hc_tx_sock *hc, u32 new_wnd)
193 { 190 {
194 hc->tx_expected_wnd = (3 * hc->tx_expe 191 hc->tx_expected_wnd = (3 * hc->tx_expected_wnd + new_wnd) / 4;
195 } 192 }
196 193
197 /* This borrows the code of tcp_cwnd_applicati 194 /* This borrows the code of tcp_cwnd_application_limited() */
198 static void ccid2_cwnd_application_limited(str 195 static void ccid2_cwnd_application_limited(struct sock *sk, const u32 now)
199 { 196 {
200 struct ccid2_hc_tx_sock *hc = ccid2_hc 197 struct ccid2_hc_tx_sock *hc = ccid2_hc_tx_sk(sk);
201 /* don't reduce cwnd below the initial 198 /* don't reduce cwnd below the initial window (IW) */
202 u32 init_win = rfc3390_bytes_to_packet 199 u32 init_win = rfc3390_bytes_to_packets(dccp_sk(sk)->dccps_mss_cache),
203 win_used = max(hc->tx_cwnd_used, i 200 win_used = max(hc->tx_cwnd_used, init_win);
204 201
205 if (win_used < hc->tx_cwnd) { 202 if (win_used < hc->tx_cwnd) {
206 hc->tx_ssthresh = max(hc->tx_s 203 hc->tx_ssthresh = max(hc->tx_ssthresh,
207 (hc->tx_c 204 (hc->tx_cwnd >> 1) + (hc->tx_cwnd >> 2));
208 hc->tx_cwnd = (hc->tx_cwnd + w 205 hc->tx_cwnd = (hc->tx_cwnd + win_used) >> 1;
209 } 206 }
210 hc->tx_cwnd_used = 0; 207 hc->tx_cwnd_used = 0;
211 hc->tx_cwnd_stamp = now; 208 hc->tx_cwnd_stamp = now;
212 209
213 ccid2_check_l_ack_ratio(sk); 210 ccid2_check_l_ack_ratio(sk);
214 } 211 }
215 212
216 /* This borrows the code of tcp_cwnd_restart() 213 /* This borrows the code of tcp_cwnd_restart() */
217 static void ccid2_cwnd_restart(struct sock *sk 214 static void ccid2_cwnd_restart(struct sock *sk, const u32 now)
218 { 215 {
219 struct ccid2_hc_tx_sock *hc = ccid2_hc 216 struct ccid2_hc_tx_sock *hc = ccid2_hc_tx_sk(sk);
220 u32 cwnd = hc->tx_cwnd, restart_cwnd, 217 u32 cwnd = hc->tx_cwnd, restart_cwnd,
221 iwnd = rfc3390_bytes_to_packets(dc 218 iwnd = rfc3390_bytes_to_packets(dccp_sk(sk)->dccps_mss_cache);
222 s32 delta = now - hc->tx_lsndtime; 219 s32 delta = now - hc->tx_lsndtime;
223 220
224 hc->tx_ssthresh = max(hc->tx_ssthresh, 221 hc->tx_ssthresh = max(hc->tx_ssthresh, (cwnd >> 1) + (cwnd >> 2));
225 222
226 /* don't reduce cwnd below the initial 223 /* don't reduce cwnd below the initial window (IW) */
227 restart_cwnd = min(cwnd, iwnd); 224 restart_cwnd = min(cwnd, iwnd);
228 225
229 while ((delta -= hc->tx_rto) >= 0 && c 226 while ((delta -= hc->tx_rto) >= 0 && cwnd > restart_cwnd)
230 cwnd >>= 1; 227 cwnd >>= 1;
231 hc->tx_cwnd = max(cwnd, restart_cwnd); 228 hc->tx_cwnd = max(cwnd, restart_cwnd);
232 hc->tx_cwnd_stamp = now; 229 hc->tx_cwnd_stamp = now;
233 hc->tx_cwnd_used = 0; 230 hc->tx_cwnd_used = 0;
234 231
235 ccid2_check_l_ack_ratio(sk); 232 ccid2_check_l_ack_ratio(sk);
236 } 233 }
237 234
238 static void ccid2_hc_tx_packet_sent(struct soc 235 static void ccid2_hc_tx_packet_sent(struct sock *sk, unsigned int len)
239 { 236 {
240 struct dccp_sock *dp = dccp_sk(sk); 237 struct dccp_sock *dp = dccp_sk(sk);
241 struct ccid2_hc_tx_sock *hc = ccid2_hc 238 struct ccid2_hc_tx_sock *hc = ccid2_hc_tx_sk(sk);
242 const u32 now = ccid2_jiffies32; 239 const u32 now = ccid2_jiffies32;
243 struct ccid2_seq *next; 240 struct ccid2_seq *next;
244 241
245 /* slow-start after idle periods (RFC 242 /* slow-start after idle periods (RFC 2581, RFC 2861) */
246 if (ccid2_do_cwv && !hc->tx_pipe && 243 if (ccid2_do_cwv && !hc->tx_pipe &&
247 (s32)(now - hc->tx_lsndtime) >= hc 244 (s32)(now - hc->tx_lsndtime) >= hc->tx_rto)
248 ccid2_cwnd_restart(sk, now); 245 ccid2_cwnd_restart(sk, now);
249 246
250 hc->tx_lsndtime = now; 247 hc->tx_lsndtime = now;
251 hc->tx_pipe += 1; 248 hc->tx_pipe += 1;
252 249
253 /* see whether cwnd was fully used (RF 250 /* see whether cwnd was fully used (RFC 2861), update expected window */
254 if (ccid2_cwnd_network_limited(hc)) { 251 if (ccid2_cwnd_network_limited(hc)) {
255 ccid2_update_used_window(hc, h 252 ccid2_update_used_window(hc, hc->tx_cwnd);
256 hc->tx_cwnd_used = 0; 253 hc->tx_cwnd_used = 0;
257 hc->tx_cwnd_stamp = now; 254 hc->tx_cwnd_stamp = now;
258 } else { 255 } else {
259 if (hc->tx_pipe > hc->tx_cwnd_ 256 if (hc->tx_pipe > hc->tx_cwnd_used)
260 hc->tx_cwnd_used = hc- 257 hc->tx_cwnd_used = hc->tx_pipe;
261 258
262 ccid2_update_used_window(hc, h 259 ccid2_update_used_window(hc, hc->tx_cwnd_used);
263 260
264 if (ccid2_do_cwv && (s32)(now 261 if (ccid2_do_cwv && (s32)(now - hc->tx_cwnd_stamp) >= hc->tx_rto)
265 ccid2_cwnd_application 262 ccid2_cwnd_application_limited(sk, now);
266 } 263 }
267 264
268 hc->tx_seqh->ccid2s_seq = dp->dccps_ 265 hc->tx_seqh->ccid2s_seq = dp->dccps_gss;
269 hc->tx_seqh->ccid2s_acked = 0; 266 hc->tx_seqh->ccid2s_acked = 0;
270 hc->tx_seqh->ccid2s_sent = now; 267 hc->tx_seqh->ccid2s_sent = now;
271 268
272 next = hc->tx_seqh->ccid2s_next; 269 next = hc->tx_seqh->ccid2s_next;
273 /* check if we need to alloc more spac 270 /* check if we need to alloc more space */
274 if (next == hc->tx_seqt) { 271 if (next == hc->tx_seqt) {
275 if (ccid2_hc_tx_alloc_seq(hc)) 272 if (ccid2_hc_tx_alloc_seq(hc)) {
276 DCCP_CRIT("packet hist 273 DCCP_CRIT("packet history - out of memory!");
277 /* FIXME: find a more 274 /* FIXME: find a more graceful way to bail out */
278 return; 275 return;
279 } 276 }
280 next = hc->tx_seqh->ccid2s_nex 277 next = hc->tx_seqh->ccid2s_next;
281 BUG_ON(next == hc->tx_seqt); 278 BUG_ON(next == hc->tx_seqt);
282 } 279 }
283 hc->tx_seqh = next; 280 hc->tx_seqh = next;
284 281
285 ccid2_pr_debug("cwnd=%d pipe=%d\n", hc 282 ccid2_pr_debug("cwnd=%d pipe=%d\n", hc->tx_cwnd, hc->tx_pipe);
286 283
287 /* 284 /*
288 * FIXME: The code below is broken and 285 * FIXME: The code below is broken and the variables have been removed
289 * from the socket struct. The `acklos 286 * from the socket struct. The `ackloss' variable was always set to 0,
290 * and with arsent there are several p 287 * and with arsent there are several problems:
291 * (i) it doesn't just count the numb 288 * (i) it doesn't just count the number of Acks, but all sent packets;
292 * (ii) it is expressed in # of packe 289 * (ii) it is expressed in # of packets, not # of windows, so the
293 * comparison below uses the wrong fo 290 * comparison below uses the wrong formula: Appendix A of RFC 4341
294 * comes up with the number K = cwnd 291 * comes up with the number K = cwnd / (R^2 - R) of consecutive windows
295 * of data with no lost or marked Ack 292 * of data with no lost or marked Ack packets. If arsent were the # of
296 * consecutive Acks received without 293 * consecutive Acks received without loss, then Ack Ratio needs to be
297 * decreased by 1 when 294 * decreased by 1 when
298 * arsent >= K * cwnd / R 295 * arsent >= K * cwnd / R = cwnd^2 / (R^3 - R^2)
299 * where cwnd / R is the number of Ac 296 * where cwnd / R is the number of Acks received per window of data
300 * (cf. RFC 4341, App. A). The proble 297 * (cf. RFC 4341, App. A). The problems are that
301 * - arsent counts other packets as w 298 * - arsent counts other packets as well;
302 * - the comparison uses a formula di 299 * - the comparison uses a formula different from RFC 4341;
303 * - computing a cubic/quadratic equa 300 * - computing a cubic/quadratic equation each time is too complicated.
304 * Hence a different algorithm is nee 301 * Hence a different algorithm is needed.
305 */ 302 */
306 #if 0 303 #if 0
307 /* Ack Ratio. Need to maintain a conc 304 /* Ack Ratio. Need to maintain a concept of how many windows we sent */
308 hc->tx_arsent++; 305 hc->tx_arsent++;
309 /* We had an ack loss in this window.. 306 /* We had an ack loss in this window... */
310 if (hc->tx_ackloss) { 307 if (hc->tx_ackloss) {
311 if (hc->tx_arsent >= hc->tx_cw 308 if (hc->tx_arsent >= hc->tx_cwnd) {
312 hc->tx_arsent = 0; 309 hc->tx_arsent = 0;
313 hc->tx_ackloss = 0; 310 hc->tx_ackloss = 0;
314 } 311 }
315 } else { 312 } else {
316 /* No acks lost up to now... * 313 /* No acks lost up to now... */
317 /* decrease ack ratio if enoug 314 /* decrease ack ratio if enough packets were sent */
318 if (dp->dccps_l_ack_ratio > 1) 315 if (dp->dccps_l_ack_ratio > 1) {
319 /* XXX don't calculate 316 /* XXX don't calculate denominator each time */
320 int denom = dp->dccps_ 317 int denom = dp->dccps_l_ack_ratio * dp->dccps_l_ack_ratio -
321 dp->dccps_ 318 dp->dccps_l_ack_ratio;
322 319
323 denom = hc->tx_cwnd * 320 denom = hc->tx_cwnd * hc->tx_cwnd / denom;
324 321
325 if (hc->tx_arsent >= d 322 if (hc->tx_arsent >= denom) {
326 ccid2_change_l 323 ccid2_change_l_ack_ratio(sk, dp->dccps_l_ack_ratio - 1);
327 hc->tx_arsent 324 hc->tx_arsent = 0;
328 } 325 }
329 } else { 326 } else {
330 /* we can't increase a 327 /* we can't increase ack ratio further [1] */
331 hc->tx_arsent = 0; /* 328 hc->tx_arsent = 0; /* or maybe set it to cwnd*/
332 } 329 }
333 } 330 }
334 #endif 331 #endif
335 332
336 sk_reset_timer(sk, &hc->tx_rtotimer, j 333 sk_reset_timer(sk, &hc->tx_rtotimer, jiffies + hc->tx_rto);
337 334
338 #ifdef CONFIG_IP_DCCP_CCID2_DEBUG 335 #ifdef CONFIG_IP_DCCP_CCID2_DEBUG
339 do { 336 do {
340 struct ccid2_seq *seqp = hc->t 337 struct ccid2_seq *seqp = hc->tx_seqt;
341 338
342 while (seqp != hc->tx_seqh) { 339 while (seqp != hc->tx_seqh) {
343 ccid2_pr_debug("out se 340 ccid2_pr_debug("out seq=%llu acked=%d time=%u\n",
344 (unsign 341 (unsigned long long)seqp->ccid2s_seq,
345 seqp->c 342 seqp->ccid2s_acked, seqp->ccid2s_sent);
346 seqp = seqp->ccid2s_ne 343 seqp = seqp->ccid2s_next;
347 } 344 }
348 } while (0); 345 } while (0);
349 ccid2_pr_debug("=========\n"); 346 ccid2_pr_debug("=========\n");
350 #endif 347 #endif
351 } 348 }
352 349
353 /** 350 /**
354 * ccid2_rtt_estimator - Sample RTT and comput 351 * ccid2_rtt_estimator - Sample RTT and compute RTO using RFC2988 algorithm
355 * @sk: socket to perform estimator on <<
356 * @mrtt: measured RTT <<
357 * <<
358 * This code is almost identical with TCP's tc 352 * This code is almost identical with TCP's tcp_rtt_estimator(), since
359 * - it has a higher sampling frequency (recom 353 * - it has a higher sampling frequency (recommended by RFC 1323),
360 * - the RTO does not collapse into RTT due to 354 * - the RTO does not collapse into RTT due to RTTVAR going towards zero,
361 * - it is simple (cf. more complex proposals 355 * - it is simple (cf. more complex proposals such as Eifel timer or research
362 * which suggests that the gain should be se 356 * which suggests that the gain should be set according to window size),
363 * - in tests it was found to work well with C 357 * - in tests it was found to work well with CCID2 [gerrit].
364 */ 358 */
365 static void ccid2_rtt_estimator(struct sock *s 359 static void ccid2_rtt_estimator(struct sock *sk, const long mrtt)
366 { 360 {
367 struct ccid2_hc_tx_sock *hc = ccid2_hc 361 struct ccid2_hc_tx_sock *hc = ccid2_hc_tx_sk(sk);
368 long m = mrtt ? : 1; 362 long m = mrtt ? : 1;
369 363
370 if (hc->tx_srtt == 0) { 364 if (hc->tx_srtt == 0) {
371 /* First measurement m */ 365 /* First measurement m */
372 hc->tx_srtt = m << 3; 366 hc->tx_srtt = m << 3;
373 hc->tx_mdev = m << 1; 367 hc->tx_mdev = m << 1;
374 368
375 hc->tx_mdev_max = max(hc->tx_m 369 hc->tx_mdev_max = max(hc->tx_mdev, tcp_rto_min(sk));
376 hc->tx_rttvar = hc->tx_mdev_ 370 hc->tx_rttvar = hc->tx_mdev_max;
377 371
378 hc->tx_rtt_seq = dccp_sk(sk)- 372 hc->tx_rtt_seq = dccp_sk(sk)->dccps_gss;
379 } else { 373 } else {
380 /* Update scaled SRTT as SRTT 374 /* Update scaled SRTT as SRTT += 1/8 * (m - SRTT) */
381 m -= (hc->tx_srtt >> 3); 375 m -= (hc->tx_srtt >> 3);
382 hc->tx_srtt += m; 376 hc->tx_srtt += m;
383 377
384 /* Similarly, update scaled md 378 /* Similarly, update scaled mdev with regard to |m| */
385 if (m < 0) { 379 if (m < 0) {
386 m = -m; 380 m = -m;
387 m -= (hc->tx_mdev >> 2 381 m -= (hc->tx_mdev >> 2);
388 /* 382 /*
389 * This neutralises RT 383 * This neutralises RTO increase when RTT < SRTT - mdev
390 * (see P. Sarolahti, 384 * (see P. Sarolahti, A. Kuznetsov,"Congestion Control
391 * in Linux TCP", USEN 385 * in Linux TCP", USENIX 2002, pp. 49-62).
392 */ 386 */
393 if (m > 0) 387 if (m > 0)
394 m >>= 3; 388 m >>= 3;
395 } else { 389 } else {
396 m -= (hc->tx_mdev >> 2 390 m -= (hc->tx_mdev >> 2);
397 } 391 }
398 hc->tx_mdev += m; 392 hc->tx_mdev += m;
399 393
400 if (hc->tx_mdev > hc->tx_mdev_ 394 if (hc->tx_mdev > hc->tx_mdev_max) {
401 hc->tx_mdev_max = hc-> 395 hc->tx_mdev_max = hc->tx_mdev;
402 if (hc->tx_mdev_max > 396 if (hc->tx_mdev_max > hc->tx_rttvar)
403 hc->tx_rttvar 397 hc->tx_rttvar = hc->tx_mdev_max;
404 } 398 }
405 399
406 /* 400 /*
407 * Decay RTTVAR at most once p 401 * Decay RTTVAR at most once per flight, exploiting that
408 * 1) pipe <= cwnd <= Sequenc 402 * 1) pipe <= cwnd <= Sequence_Window = W (RFC 4340, 7.5.2)
409 * 2) AWL = GSS-W+1 <= GAR <= 403 * 2) AWL = GSS-W+1 <= GAR <= GSS (RFC 4340, 7.5.1)
410 * GAR is a useful bound for F 404 * GAR is a useful bound for FlightSize = pipe.
411 * AWL is probably too low her 405 * AWL is probably too low here, as it over-estimates pipe.
412 */ 406 */
413 if (after48(dccp_sk(sk)->dccps 407 if (after48(dccp_sk(sk)->dccps_gar, hc->tx_rtt_seq)) {
414 if (hc->tx_mdev_max < 408 if (hc->tx_mdev_max < hc->tx_rttvar)
415 hc->tx_rttvar 409 hc->tx_rttvar -= (hc->tx_rttvar -
416 410 hc->tx_mdev_max) >> 2;
417 hc->tx_rtt_seq = dccp 411 hc->tx_rtt_seq = dccp_sk(sk)->dccps_gss;
418 hc->tx_mdev_max = tcp_ 412 hc->tx_mdev_max = tcp_rto_min(sk);
419 } 413 }
420 } 414 }
421 415
422 /* 416 /*
423 * Set RTO from SRTT and RTTVAR 417 * Set RTO from SRTT and RTTVAR
424 * As in TCP, 4 * RTTVAR >= TCP_RTO_MI 418 * As in TCP, 4 * RTTVAR >= TCP_RTO_MIN, giving a minimum RTO of 200 ms.
425 * This agrees with RFC 4341, 5: 419 * This agrees with RFC 4341, 5:
426 * "Because DCCP does not retrans 420 * "Because DCCP does not retransmit data, DCCP does not require
427 * TCP's recommended minimum tim 421 * TCP's recommended minimum timeout of one second".
428 */ 422 */
429 hc->tx_rto = (hc->tx_srtt >> 3) + hc-> 423 hc->tx_rto = (hc->tx_srtt >> 3) + hc->tx_rttvar;
430 424
431 if (hc->tx_rto > DCCP_RTO_MAX) 425 if (hc->tx_rto > DCCP_RTO_MAX)
432 hc->tx_rto = DCCP_RTO_MAX; 426 hc->tx_rto = DCCP_RTO_MAX;
433 } 427 }
434 428
435 static void ccid2_new_ack(struct sock *sk, str 429 static void ccid2_new_ack(struct sock *sk, struct ccid2_seq *seqp,
436 unsigned int *maxinc 430 unsigned int *maxincr)
437 { 431 {
438 struct ccid2_hc_tx_sock *hc = ccid2_hc 432 struct ccid2_hc_tx_sock *hc = ccid2_hc_tx_sk(sk);
439 struct dccp_sock *dp = dccp_sk(sk); 433 struct dccp_sock *dp = dccp_sk(sk);
440 int r_seq_used = hc->tx_cwnd / dp->dcc 434 int r_seq_used = hc->tx_cwnd / dp->dccps_l_ack_ratio;
441 435
442 if (hc->tx_cwnd < dp->dccps_l_seq_win 436 if (hc->tx_cwnd < dp->dccps_l_seq_win &&
443 r_seq_used < dp->dccps_r_seq_win) 437 r_seq_used < dp->dccps_r_seq_win) {
444 if (hc->tx_cwnd < hc->tx_ssthr 438 if (hc->tx_cwnd < hc->tx_ssthresh) {
445 if (*maxincr > 0 && ++ 439 if (*maxincr > 0 && ++hc->tx_packets_acked >= 2) {
446 hc->tx_cwnd += 440 hc->tx_cwnd += 1;
447 *maxincr -= 441 *maxincr -= 1;
448 hc->tx_packets 442 hc->tx_packets_acked = 0;
449 } 443 }
450 } else if (++hc->tx_packets_ac 444 } else if (++hc->tx_packets_acked >= hc->tx_cwnd) {
451 hc->tx_cwnd += 1; 445 hc->tx_cwnd += 1;
452 hc->tx_packets_acked = 446 hc->tx_packets_acked = 0;
453 } 447 }
454 } 448 }
455 449
456 /* 450 /*
457 * Adjust the local sequence window an 451 * Adjust the local sequence window and the ack ratio to allow about
458 * 5 times the number of packets in th 452 * 5 times the number of packets in the network (RFC 4340 7.5.2)
459 */ 453 */
460 if (r_seq_used * CCID2_WIN_CHANGE_FACT 454 if (r_seq_used * CCID2_WIN_CHANGE_FACTOR >= dp->dccps_r_seq_win)
461 ccid2_change_l_ack_ratio(sk, d 455 ccid2_change_l_ack_ratio(sk, dp->dccps_l_ack_ratio * 2);
462 else if (r_seq_used * CCID2_WIN_CHANGE 456 else if (r_seq_used * CCID2_WIN_CHANGE_FACTOR < dp->dccps_r_seq_win/2)
463 ccid2_change_l_ack_ratio(sk, d 457 ccid2_change_l_ack_ratio(sk, dp->dccps_l_ack_ratio / 2 ? : 1U);
464 458
465 if (hc->tx_cwnd * CCID2_WIN_CHANGE_FAC 459 if (hc->tx_cwnd * CCID2_WIN_CHANGE_FACTOR >= dp->dccps_l_seq_win)
466 ccid2_change_l_seq_window(sk, 460 ccid2_change_l_seq_window(sk, dp->dccps_l_seq_win * 2);
467 else if (hc->tx_cwnd * CCID2_WIN_CHANG 461 else if (hc->tx_cwnd * CCID2_WIN_CHANGE_FACTOR < dp->dccps_l_seq_win/2)
468 ccid2_change_l_seq_window(sk, 462 ccid2_change_l_seq_window(sk, dp->dccps_l_seq_win / 2);
469 463
470 /* 464 /*
471 * FIXME: RTT is sampled several times 465 * FIXME: RTT is sampled several times per acknowledgment (for each
472 * entry in the Ack Vector), instead o 466 * entry in the Ack Vector), instead of once per Ack (as in TCP SACK).
473 * This causes the RTT to be over-esti 467 * This causes the RTT to be over-estimated, since the older entries
474 * in the Ack Vector have earlier send 468 * in the Ack Vector have earlier sending times.
475 * The cleanest solution is to not use 469 * The cleanest solution is to not use the ccid2s_sent field at all
476 * and instead use DCCP timestamps: re 470 * and instead use DCCP timestamps: requires changes in other places.
477 */ 471 */
478 ccid2_rtt_estimator(sk, ccid2_jiffies3 472 ccid2_rtt_estimator(sk, ccid2_jiffies32 - seqp->ccid2s_sent);
479 } 473 }
480 474
481 static void ccid2_congestion_event(struct sock 475 static void ccid2_congestion_event(struct sock *sk, struct ccid2_seq *seqp)
482 { 476 {
483 struct ccid2_hc_tx_sock *hc = ccid2_hc 477 struct ccid2_hc_tx_sock *hc = ccid2_hc_tx_sk(sk);
484 478
485 if ((s32)(seqp->ccid2s_sent - hc->tx_l 479 if ((s32)(seqp->ccid2s_sent - hc->tx_last_cong) < 0) {
486 ccid2_pr_debug("Multiple losse 480 ccid2_pr_debug("Multiple losses in an RTT---treating as one\n");
487 return; 481 return;
488 } 482 }
489 483
490 hc->tx_last_cong = ccid2_jiffies32; 484 hc->tx_last_cong = ccid2_jiffies32;
491 485
492 hc->tx_cwnd = hc->tx_cwnd / 2 ? : 486 hc->tx_cwnd = hc->tx_cwnd / 2 ? : 1U;
493 hc->tx_ssthresh = max(hc->tx_cwnd, 2U 487 hc->tx_ssthresh = max(hc->tx_cwnd, 2U);
494 488
495 ccid2_check_l_ack_ratio(sk); 489 ccid2_check_l_ack_ratio(sk);
496 } 490 }
497 491
498 static int ccid2_hc_tx_parse_options(struct so 492 static int ccid2_hc_tx_parse_options(struct sock *sk, u8 packet_type,
499 u8 option 493 u8 option, u8 *optval, u8 optlen)
500 { 494 {
501 struct ccid2_hc_tx_sock *hc = ccid2_hc 495 struct ccid2_hc_tx_sock *hc = ccid2_hc_tx_sk(sk);
502 496
503 switch (option) { 497 switch (option) {
504 case DCCPO_ACK_VECTOR_0: 498 case DCCPO_ACK_VECTOR_0:
505 case DCCPO_ACK_VECTOR_1: 499 case DCCPO_ACK_VECTOR_1:
506 return dccp_ackvec_parsed_add( 500 return dccp_ackvec_parsed_add(&hc->tx_av_chunks, optval, optlen,
507 501 option - DCCPO_ACK_VECTOR_0);
508 } 502 }
509 return 0; 503 return 0;
510 } 504 }
511 505
512 static void ccid2_hc_tx_packet_recv(struct soc 506 static void ccid2_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb)
513 { 507 {
514 struct dccp_sock *dp = dccp_sk(sk); 508 struct dccp_sock *dp = dccp_sk(sk);
515 struct ccid2_hc_tx_sock *hc = ccid2_hc 509 struct ccid2_hc_tx_sock *hc = ccid2_hc_tx_sk(sk);
516 const bool sender_was_blocked = ccid2_ 510 const bool sender_was_blocked = ccid2_cwnd_network_limited(hc);
517 struct dccp_ackvec_parsed *avp; 511 struct dccp_ackvec_parsed *avp;
518 u64 ackno, seqno; 512 u64 ackno, seqno;
519 struct ccid2_seq *seqp; 513 struct ccid2_seq *seqp;
520 int done = 0; 514 int done = 0;
521 unsigned int maxincr = 0; 515 unsigned int maxincr = 0;
522 516
523 /* check reverse path congestion */ 517 /* check reverse path congestion */
524 seqno = DCCP_SKB_CB(skb)->dccpd_seq; 518 seqno = DCCP_SKB_CB(skb)->dccpd_seq;
525 519
526 /* XXX this whole "algorithm" is broke 520 /* XXX this whole "algorithm" is broken. Need to fix it to keep track
527 * of the seqnos of the dupacks so tha 521 * of the seqnos of the dupacks so that rpseq and rpdupack are correct
528 * -sorbo. 522 * -sorbo.
529 */ 523 */
530 /* need to bootstrap */ 524 /* need to bootstrap */
531 if (hc->tx_rpdupack == -1) { 525 if (hc->tx_rpdupack == -1) {
532 hc->tx_rpdupack = 0; 526 hc->tx_rpdupack = 0;
533 hc->tx_rpseq = seqno; 527 hc->tx_rpseq = seqno;
534 } else { 528 } else {
535 /* check if packet is consecut 529 /* check if packet is consecutive */
536 if (dccp_delta_seqno(hc->tx_rp 530 if (dccp_delta_seqno(hc->tx_rpseq, seqno) == 1)
537 hc->tx_rpseq = seqno; 531 hc->tx_rpseq = seqno;
538 /* it's a later packet */ 532 /* it's a later packet */
539 else if (after48(seqno, hc->tx 533 else if (after48(seqno, hc->tx_rpseq)) {
540 hc->tx_rpdupack++; 534 hc->tx_rpdupack++;
541 535
542 /* check if we got eno 536 /* check if we got enough dupacks */
543 if (hc->tx_rpdupack >= 537 if (hc->tx_rpdupack >= NUMDUPACK) {
544 hc->tx_rpdupac 538 hc->tx_rpdupack = -1; /* XXX lame */
545 hc->tx_rpseq 539 hc->tx_rpseq = 0;
546 #ifdef __CCID2_COPES_GRACEFULLY_WITH_ACK_CONGE 540 #ifdef __CCID2_COPES_GRACEFULLY_WITH_ACK_CONGESTION_CONTROL__
547 /* 541 /*
548 * FIXME: Ack 542 * FIXME: Ack Congestion Control is broken; in
549 * the current 543 * the current state instabilities occurred with
550 * Ack Ratios 544 * Ack Ratios greater than 1; causing hang-ups
551 * and long RT 545 * and long RTO timeouts. This needs to be fixed
552 * before open 546 * before opening up dynamic changes. -- gerrit
553 */ 547 */
554 ccid2_change_l 548 ccid2_change_l_ack_ratio(sk, 2 * dp->dccps_l_ack_ratio);
555 #endif 549 #endif
556 } 550 }
557 } 551 }
558 } 552 }
559 553
560 /* check forward path congestion */ 554 /* check forward path congestion */
561 if (dccp_packet_without_ack(skb)) 555 if (dccp_packet_without_ack(skb))
562 return; 556 return;
563 557
564 /* still didn't send out new data pack 558 /* still didn't send out new data packets */
565 if (hc->tx_seqh == hc->tx_seqt) 559 if (hc->tx_seqh == hc->tx_seqt)
566 goto done; 560 goto done;
567 561
568 ackno = DCCP_SKB_CB(skb)->dccpd_ack_se 562 ackno = DCCP_SKB_CB(skb)->dccpd_ack_seq;
569 if (after48(ackno, hc->tx_high_ack)) 563 if (after48(ackno, hc->tx_high_ack))
570 hc->tx_high_ack = ackno; 564 hc->tx_high_ack = ackno;
571 565
572 seqp = hc->tx_seqt; 566 seqp = hc->tx_seqt;
573 while (before48(seqp->ccid2s_seq, ackn 567 while (before48(seqp->ccid2s_seq, ackno)) {
574 seqp = seqp->ccid2s_next; 568 seqp = seqp->ccid2s_next;
575 if (seqp == hc->tx_seqh) { 569 if (seqp == hc->tx_seqh) {
576 seqp = hc->tx_seqh->cc 570 seqp = hc->tx_seqh->ccid2s_prev;
577 break; 571 break;
578 } 572 }
579 } 573 }
580 574
581 /* 575 /*
582 * In slow-start, cwnd can increase up 576 * In slow-start, cwnd can increase up to a maximum of Ack Ratio/2
583 * packets per acknowledgement. Roundi 577 * packets per acknowledgement. Rounding up avoids that cwnd is not
584 * advanced when Ack Ratio is 1 and gi 578 * advanced when Ack Ratio is 1 and gives a slight edge otherwise.
585 */ 579 */
586 if (hc->tx_cwnd < hc->tx_ssthresh) 580 if (hc->tx_cwnd < hc->tx_ssthresh)
587 maxincr = DIV_ROUND_UP(dp->dcc 581 maxincr = DIV_ROUND_UP(dp->dccps_l_ack_ratio, 2);
588 582
589 /* go through all ack vectors */ 583 /* go through all ack vectors */
590 list_for_each_entry(avp, &hc->tx_av_ch 584 list_for_each_entry(avp, &hc->tx_av_chunks, node) {
591 /* go through this ack vector 585 /* go through this ack vector */
592 for (; avp->len--; avp->vec++) 586 for (; avp->len--; avp->vec++) {
593 u64 ackno_end_rl = SUB 587 u64 ackno_end_rl = SUB48(ackno,
594 588 dccp_ackvec_runlen(avp->vec));
595 589
596 ccid2_pr_debug("ackvec 590 ccid2_pr_debug("ackvec %llu |%u,%u|\n",
597 (unsign 591 (unsigned long long)ackno,
598 dccp_ac 592 dccp_ackvec_state(avp->vec) >> 6,
599 dccp_ac 593 dccp_ackvec_runlen(avp->vec));
600 /* if the seqno we are 594 /* if the seqno we are analyzing is larger than the
601 * current ackno, then 595 * current ackno, then move towards the tail of our
602 * seqnos. 596 * seqnos.
603 */ 597 */
604 while (after48(seqp->c 598 while (after48(seqp->ccid2s_seq, ackno)) {
605 if (seqp == hc 599 if (seqp == hc->tx_seqt) {
606 done = 600 done = 1;
607 break; 601 break;
608 } 602 }
609 seqp = seqp->c 603 seqp = seqp->ccid2s_prev;
610 } 604 }
611 if (done) 605 if (done)
612 break; 606 break;
613 607
614 /* check all seqnos in 608 /* check all seqnos in the range of the vector
615 * run length 609 * run length
616 */ 610 */
617 while (between48(seqp- 611 while (between48(seqp->ccid2s_seq,ackno_end_rl,ackno)) {
618 const u8 state 612 const u8 state = dccp_ackvec_state(avp->vec);
619 613
620 /* new packet 614 /* new packet received or marked */
621 if (state != D 615 if (state != DCCPAV_NOT_RECEIVED &&
622 !seqp->cci 616 !seqp->ccid2s_acked) {
623 if (st 617 if (state == DCCPAV_ECN_MARKED)
624 618 ccid2_congestion_event(sk,
625 619 seqp);
626 else 620 else
627 621 ccid2_new_ack(sk, seqp,
628 622 &maxincr);
629 623
630 seqp-> 624 seqp->ccid2s_acked = 1;
631 ccid2_ 625 ccid2_pr_debug("Got ack for %llu\n",
632 626 (unsigned long long)seqp->ccid2s_seq);
633 hc->tx 627 hc->tx_pipe--;
634 } 628 }
635 if (seqp == hc 629 if (seqp == hc->tx_seqt) {
636 done = 630 done = 1;
637 break; 631 break;
638 } 632 }
639 seqp = seqp->c 633 seqp = seqp->ccid2s_prev;
640 } 634 }
641 if (done) 635 if (done)
642 break; 636 break;
643 637
644 ackno = SUB48(ackno_en 638 ackno = SUB48(ackno_end_rl, 1);
645 } 639 }
646 if (done) 640 if (done)
647 break; 641 break;
648 } 642 }
649 643
650 /* The state about what is acked shoul 644 /* The state about what is acked should be correct now
651 * Check for NUMDUPACK 645 * Check for NUMDUPACK
652 */ 646 */
653 seqp = hc->tx_seqt; 647 seqp = hc->tx_seqt;
654 while (before48(seqp->ccid2s_seq, hc-> 648 while (before48(seqp->ccid2s_seq, hc->tx_high_ack)) {
655 seqp = seqp->ccid2s_next; 649 seqp = seqp->ccid2s_next;
656 if (seqp == hc->tx_seqh) { 650 if (seqp == hc->tx_seqh) {
657 seqp = hc->tx_seqh->cc 651 seqp = hc->tx_seqh->ccid2s_prev;
658 break; 652 break;
659 } 653 }
660 } 654 }
661 done = 0; 655 done = 0;
662 while (1) { 656 while (1) {
663 if (seqp->ccid2s_acked) { 657 if (seqp->ccid2s_acked) {
664 done++; 658 done++;
665 if (done == NUMDUPACK) 659 if (done == NUMDUPACK)
666 break; 660 break;
667 } 661 }
668 if (seqp == hc->tx_seqt) 662 if (seqp == hc->tx_seqt)
669 break; 663 break;
670 seqp = seqp->ccid2s_prev; 664 seqp = seqp->ccid2s_prev;
671 } 665 }
672 666
673 /* If there are at least 3 acknowledge 667 /* If there are at least 3 acknowledgements, anything unacknowledged
674 * below the last sequence number is c 668 * below the last sequence number is considered lost
675 */ 669 */
676 if (done == NUMDUPACK) { 670 if (done == NUMDUPACK) {
677 struct ccid2_seq *last_acked = 671 struct ccid2_seq *last_acked = seqp;
678 672
679 /* check for lost packets */ 673 /* check for lost packets */
680 while (1) { 674 while (1) {
681 if (!seqp->ccid2s_acke 675 if (!seqp->ccid2s_acked) {
682 ccid2_pr_debug 676 ccid2_pr_debug("Packet lost: %llu\n",
683 677 (unsigned long long)seqp->ccid2s_seq);
684 /* XXX need to 678 /* XXX need to traverse from tail -> head in
685 * order to de 679 * order to detect multiple congestion events in
686 * one ack vec 680 * one ack vector.
687 */ 681 */
688 ccid2_congesti 682 ccid2_congestion_event(sk, seqp);
689 hc->tx_pipe--; 683 hc->tx_pipe--;
690 } 684 }
691 if (seqp == hc->tx_seq 685 if (seqp == hc->tx_seqt)
692 break; 686 break;
693 seqp = seqp->ccid2s_pr 687 seqp = seqp->ccid2s_prev;
694 } 688 }
695 689
696 hc->tx_seqt = last_acked; 690 hc->tx_seqt = last_acked;
697 } 691 }
698 692
699 /* trim acked packets in tail */ 693 /* trim acked packets in tail */
700 while (hc->tx_seqt != hc->tx_seqh) { 694 while (hc->tx_seqt != hc->tx_seqh) {
701 if (!hc->tx_seqt->ccid2s_acked 695 if (!hc->tx_seqt->ccid2s_acked)
702 break; 696 break;
703 697
704 hc->tx_seqt = hc->tx_seqt->cci 698 hc->tx_seqt = hc->tx_seqt->ccid2s_next;
705 } 699 }
706 700
707 /* restart RTO timer if not all outsta 701 /* restart RTO timer if not all outstanding data has been acked */
708 if (hc->tx_pipe == 0) 702 if (hc->tx_pipe == 0)
709 sk_stop_timer(sk, &hc->tx_rtot 703 sk_stop_timer(sk, &hc->tx_rtotimer);
710 else 704 else
711 sk_reset_timer(sk, &hc->tx_rto 705 sk_reset_timer(sk, &hc->tx_rtotimer, jiffies + hc->tx_rto);
712 done: 706 done:
713 /* check if incoming Acks allow pendin 707 /* check if incoming Acks allow pending packets to be sent */
714 if (sender_was_blocked && !ccid2_cwnd_ 708 if (sender_was_blocked && !ccid2_cwnd_network_limited(hc))
715 dccp_tasklet_schedule(sk); 709 dccp_tasklet_schedule(sk);
716 dccp_ackvec_parsed_cleanup(&hc->tx_av_ 710 dccp_ackvec_parsed_cleanup(&hc->tx_av_chunks);
717 } 711 }
718 712
719 static int ccid2_hc_tx_init(struct ccid *ccid, 713 static int ccid2_hc_tx_init(struct ccid *ccid, struct sock *sk)
720 { 714 {
721 struct ccid2_hc_tx_sock *hc = ccid_pri 715 struct ccid2_hc_tx_sock *hc = ccid_priv(ccid);
722 struct dccp_sock *dp = dccp_sk(sk); 716 struct dccp_sock *dp = dccp_sk(sk);
723 u32 max_ratio; 717 u32 max_ratio;
724 718
725 /* RFC 4341, 5: initialise ssthresh to 719 /* RFC 4341, 5: initialise ssthresh to arbitrarily high (max) value */
726 hc->tx_ssthresh = ~0U; 720 hc->tx_ssthresh = ~0U;
727 721
728 /* Use larger initial windows (RFC 434 722 /* Use larger initial windows (RFC 4341, section 5). */
729 hc->tx_cwnd = rfc3390_bytes_to_packets 723 hc->tx_cwnd = rfc3390_bytes_to_packets(dp->dccps_mss_cache);
730 hc->tx_expected_wnd = hc->tx_cwnd; 724 hc->tx_expected_wnd = hc->tx_cwnd;
731 725
732 /* Make sure that Ack Ratio is enabled 726 /* Make sure that Ack Ratio is enabled and within bounds. */
733 max_ratio = DIV_ROUND_UP(hc->tx_cwnd, 727 max_ratio = DIV_ROUND_UP(hc->tx_cwnd, 2);
734 if (dp->dccps_l_ack_ratio == 0 || dp-> 728 if (dp->dccps_l_ack_ratio == 0 || dp->dccps_l_ack_ratio > max_ratio)
735 dp->dccps_l_ack_ratio = max_ra 729 dp->dccps_l_ack_ratio = max_ratio;
736 730
737 /* XXX init ~ to window size... */ 731 /* XXX init ~ to window size... */
738 if (ccid2_hc_tx_alloc_seq(hc)) 732 if (ccid2_hc_tx_alloc_seq(hc))
739 return -ENOMEM; 733 return -ENOMEM;
740 734
741 hc->tx_rto = DCCP_TIMEOUT_INIT; 735 hc->tx_rto = DCCP_TIMEOUT_INIT;
742 hc->tx_rpdupack = -1; 736 hc->tx_rpdupack = -1;
743 hc->tx_last_cong = hc->tx_lsndtime = h 737 hc->tx_last_cong = hc->tx_lsndtime = hc->tx_cwnd_stamp = ccid2_jiffies32;
744 hc->tx_cwnd_used = 0; 738 hc->tx_cwnd_used = 0;
745 hc->sk = sk; 739 hc->sk = sk;
746 timer_setup(&hc->tx_rtotimer, ccid2_hc 740 timer_setup(&hc->tx_rtotimer, ccid2_hc_tx_rto_expire, 0);
747 INIT_LIST_HEAD(&hc->tx_av_chunks); 741 INIT_LIST_HEAD(&hc->tx_av_chunks);
748 return 0; 742 return 0;
749 } 743 }
750 744
751 static void ccid2_hc_tx_exit(struct sock *sk) 745 static void ccid2_hc_tx_exit(struct sock *sk)
752 { 746 {
753 struct ccid2_hc_tx_sock *hc = ccid2_hc 747 struct ccid2_hc_tx_sock *hc = ccid2_hc_tx_sk(sk);
754 int i; 748 int i;
755 749
756 sk_stop_timer(sk, &hc->tx_rtotimer); 750 sk_stop_timer(sk, &hc->tx_rtotimer);
757 751
758 for (i = 0; i < hc->tx_seqbufc; i++) 752 for (i = 0; i < hc->tx_seqbufc; i++)
759 kfree(hc->tx_seqbuf[i]); 753 kfree(hc->tx_seqbuf[i]);
760 hc->tx_seqbufc = 0; 754 hc->tx_seqbufc = 0;
761 dccp_ackvec_parsed_cleanup(&hc->tx_av_ 755 dccp_ackvec_parsed_cleanup(&hc->tx_av_chunks);
762 } 756 }
763 757
764 static void ccid2_hc_rx_packet_recv(struct soc 758 static void ccid2_hc_rx_packet_recv(struct sock *sk, struct sk_buff *skb)
765 { 759 {
766 struct ccid2_hc_rx_sock *hc = ccid2_hc 760 struct ccid2_hc_rx_sock *hc = ccid2_hc_rx_sk(sk);
767 761
768 if (!dccp_data_packet(skb)) 762 if (!dccp_data_packet(skb))
769 return; 763 return;
770 764
771 if (++hc->rx_num_data_pkts >= dccp_sk( 765 if (++hc->rx_num_data_pkts >= dccp_sk(sk)->dccps_r_ack_ratio) {
772 dccp_send_ack(sk); 766 dccp_send_ack(sk);
773 hc->rx_num_data_pkts = 0; 767 hc->rx_num_data_pkts = 0;
774 } 768 }
775 } 769 }
776 770
777 struct ccid_operations ccid2_ops = { 771 struct ccid_operations ccid2_ops = {
778 .ccid_id = DCCPC_CCID 772 .ccid_id = DCCPC_CCID2,
779 .ccid_name = "TCP-like" 773 .ccid_name = "TCP-like",
780 .ccid_hc_tx_obj_size = sizeof(str 774 .ccid_hc_tx_obj_size = sizeof(struct ccid2_hc_tx_sock),
781 .ccid_hc_tx_init = ccid2_hc_t 775 .ccid_hc_tx_init = ccid2_hc_tx_init,
782 .ccid_hc_tx_exit = ccid2_hc_t 776 .ccid_hc_tx_exit = ccid2_hc_tx_exit,
783 .ccid_hc_tx_send_packet = ccid2_hc_t 777 .ccid_hc_tx_send_packet = ccid2_hc_tx_send_packet,
784 .ccid_hc_tx_packet_sent = ccid2_hc_t 778 .ccid_hc_tx_packet_sent = ccid2_hc_tx_packet_sent,
785 .ccid_hc_tx_parse_options = ccid2_hc_t 779 .ccid_hc_tx_parse_options = ccid2_hc_tx_parse_options,
786 .ccid_hc_tx_packet_recv = ccid2_hc_t 780 .ccid_hc_tx_packet_recv = ccid2_hc_tx_packet_recv,
787 .ccid_hc_rx_obj_size = sizeof(str 781 .ccid_hc_rx_obj_size = sizeof(struct ccid2_hc_rx_sock),
788 .ccid_hc_rx_packet_recv = ccid2_hc_r 782 .ccid_hc_rx_packet_recv = ccid2_hc_rx_packet_recv,
789 }; 783 };
790 784
791 #ifdef CONFIG_IP_DCCP_CCID2_DEBUG 785 #ifdef CONFIG_IP_DCCP_CCID2_DEBUG
792 module_param(ccid2_debug, bool, 0644); 786 module_param(ccid2_debug, bool, 0644);
793 MODULE_PARM_DESC(ccid2_debug, "Enable CCID-2 d 787 MODULE_PARM_DESC(ccid2_debug, "Enable CCID-2 debug messages");
794 #endif 788 #endif
795 789
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