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1/* Management of Tx window, Tx resend, ACKs and out-of-sequence reception
2 *
3 * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
4 * Written by David Howells (dhowells@redhat.com)
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
10 */
11
12#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
13
14#include <linux/module.h>
15#include <linux/circ_buf.h>
16#include <linux/net.h>
17#include <linux/skbuff.h>
18#include <linux/slab.h>
19#include <linux/udp.h>
20#include <net/sock.h>
21#include <net/af_rxrpc.h>
22#include "ar-internal.h"
23
24/*
25 * Propose a PING ACK be sent.
26 */
27static void rxrpc_propose_ping(struct rxrpc_call *call,
28 bool immediate, bool background)
29{
30 if (immediate) {
31 if (background &&
32 !test_and_set_bit(RXRPC_CALL_EV_PING, &call->events))
33 rxrpc_queue_call(call);
34 } else {
35 unsigned long now = jiffies;
36 unsigned long ping_at = now + rxrpc_idle_ack_delay;
37
38 if (time_before(ping_at, call->ping_at)) {
39 WRITE_ONCE(call->ping_at, ping_at);
40 rxrpc_reduce_call_timer(call, ping_at, now,
41 rxrpc_timer_set_for_ping);
42 }
43 }
44}
45
46/*
47 * propose an ACK be sent
48 */
49static void __rxrpc_propose_ACK(struct rxrpc_call *call, u8 ack_reason,
50 u16 skew, u32 serial, bool immediate,
51 bool background,
52 enum rxrpc_propose_ack_trace why)
53{
54 enum rxrpc_propose_ack_outcome outcome = rxrpc_propose_ack_use;
55 unsigned long expiry = rxrpc_soft_ack_delay;
56 s8 prior = rxrpc_ack_priority[ack_reason];
57
58 /* Pings are handled specially because we don't want to accidentally
59 * lose a ping response by subsuming it into a ping.
60 */
61 if (ack_reason == RXRPC_ACK_PING) {
62 rxrpc_propose_ping(call, immediate, background);
63 goto trace;
64 }
65
66 /* Update DELAY, IDLE, REQUESTED and PING_RESPONSE ACK serial
67 * numbers, but we don't alter the timeout.
68 */
69 _debug("prior %u %u vs %u %u",
70 ack_reason, prior,
71 call->ackr_reason, rxrpc_ack_priority[call->ackr_reason]);
72 if (ack_reason == call->ackr_reason) {
73 if (RXRPC_ACK_UPDATEABLE & (1 << ack_reason)) {
74 outcome = rxrpc_propose_ack_update;
75 call->ackr_serial = serial;
76 call->ackr_skew = skew;
77 }
78 if (!immediate)
79 goto trace;
80 } else if (prior > rxrpc_ack_priority[call->ackr_reason]) {
81 call->ackr_reason = ack_reason;
82 call->ackr_serial = serial;
83 call->ackr_skew = skew;
84 } else {
85 outcome = rxrpc_propose_ack_subsume;
86 }
87
88 switch (ack_reason) {
89 case RXRPC_ACK_REQUESTED:
90 if (rxrpc_requested_ack_delay < expiry)
91 expiry = rxrpc_requested_ack_delay;
92 if (serial == 1)
93 immediate = false;
94 break;
95
96 case RXRPC_ACK_DELAY:
97 if (rxrpc_soft_ack_delay < expiry)
98 expiry = rxrpc_soft_ack_delay;
99 break;
100
101 case RXRPC_ACK_IDLE:
102 if (rxrpc_idle_ack_delay < expiry)
103 expiry = rxrpc_idle_ack_delay;
104 break;
105
106 default:
107 immediate = true;
108 break;
109 }
110
111 if (test_bit(RXRPC_CALL_EV_ACK, &call->events)) {
112 _debug("already scheduled");
113 } else if (immediate || expiry == 0) {
114 _debug("immediate ACK %lx", call->events);
115 if (!test_and_set_bit(RXRPC_CALL_EV_ACK, &call->events) &&
116 background)
117 rxrpc_queue_call(call);
118 } else {
119 unsigned long now = jiffies, ack_at;
120
121 if (call->peer->rtt_usage > 0)
122 ack_at = nsecs_to_jiffies(call->peer->rtt);
123 else
124 ack_at = expiry;
125
126 ack_at += now;
127 if (time_before(ack_at, call->ack_at)) {
128 WRITE_ONCE(call->ack_at, ack_at);
129 rxrpc_reduce_call_timer(call, ack_at, now,
130 rxrpc_timer_set_for_ack);
131 }
132 }
133
134trace:
135 trace_rxrpc_propose_ack(call, why, ack_reason, serial, immediate,
136 background, outcome);
137}
138
139/*
140 * propose an ACK be sent, locking the call structure
141 */
142void rxrpc_propose_ACK(struct rxrpc_call *call, u8 ack_reason,
143 u16 skew, u32 serial, bool immediate, bool background,
144 enum rxrpc_propose_ack_trace why)
145{
146 spin_lock_bh(&call->lock);
147 __rxrpc_propose_ACK(call, ack_reason, skew, serial,
148 immediate, background, why);
149 spin_unlock_bh(&call->lock);
150}
151
152/*
153 * Handle congestion being detected by the retransmit timeout.
154 */
155static void rxrpc_congestion_timeout(struct rxrpc_call *call)
156{
157 set_bit(RXRPC_CALL_RETRANS_TIMEOUT, &call->flags);
158}
159
160/*
161 * Perform retransmission of NAK'd and unack'd packets.
162 */
163static void rxrpc_resend(struct rxrpc_call *call, unsigned long now_j)
164{
165 struct rxrpc_skb_priv *sp;
166 struct sk_buff *skb;
167 unsigned long resend_at;
168 rxrpc_seq_t cursor, seq, top;
169 ktime_t now, max_age, oldest, ack_ts, timeout, min_timeo;
170 int ix;
171 u8 annotation, anno_type, retrans = 0, unacked = 0;
172
173 _enter("{%d,%d}", call->tx_hard_ack, call->tx_top);
174
175 if (call->peer->rtt_usage > 1)
176 timeout = ns_to_ktime(call->peer->rtt * 3 / 2);
177 else
178 timeout = ms_to_ktime(rxrpc_resend_timeout);
179 min_timeo = ns_to_ktime((1000000000 / HZ) * 4);
180 if (ktime_before(timeout, min_timeo))
181 timeout = min_timeo;
182
183 now = ktime_get_real();
184 max_age = ktime_sub(now, timeout);
185
186 spin_lock_bh(&call->lock);
187
188 cursor = call->tx_hard_ack;
189 top = call->tx_top;
190 ASSERT(before_eq(cursor, top));
191 if (cursor == top)
192 goto out_unlock;
193
194 /* Scan the packet list without dropping the lock and decide which of
195 * the packets in the Tx buffer we're going to resend and what the new
196 * resend timeout will be.
197 */
198 trace_rxrpc_resend(call, (cursor + 1) & RXRPC_RXTX_BUFF_MASK);
199 oldest = now;
200 for (seq = cursor + 1; before_eq(seq, top); seq++) {
201 ix = seq & RXRPC_RXTX_BUFF_MASK;
202 annotation = call->rxtx_annotations[ix];
203 anno_type = annotation & RXRPC_TX_ANNO_MASK;
204 annotation &= ~RXRPC_TX_ANNO_MASK;
205 if (anno_type == RXRPC_TX_ANNO_ACK)
206 continue;
207
208 skb = call->rxtx_buffer[ix];
209 rxrpc_see_skb(skb, rxrpc_skb_tx_seen);
210 sp = rxrpc_skb(skb);
211
212 if (anno_type == RXRPC_TX_ANNO_UNACK) {
213 if (ktime_after(skb->tstamp, max_age)) {
214 if (ktime_before(skb->tstamp, oldest))
215 oldest = skb->tstamp;
216 continue;
217 }
218 if (!(annotation & RXRPC_TX_ANNO_RESENT))
219 unacked++;
220 }
221
222 /* Okay, we need to retransmit a packet. */
223 call->rxtx_annotations[ix] = RXRPC_TX_ANNO_RETRANS | annotation;
224 retrans++;
225 trace_rxrpc_retransmit(call, seq, annotation | anno_type,
226 ktime_to_ns(ktime_sub(skb->tstamp, max_age)));
227 }
228
229 resend_at = nsecs_to_jiffies(ktime_to_ns(ktime_sub(now, oldest)));
230 resend_at += jiffies + rxrpc_resend_timeout;
231 WRITE_ONCE(call->resend_at, resend_at);
232
233 if (unacked)
234 rxrpc_congestion_timeout(call);
235
236 /* If there was nothing that needed retransmission then it's likely
237 * that an ACK got lost somewhere. Send a ping to find out instead of
238 * retransmitting data.
239 */
240 if (!retrans) {
241 rxrpc_reduce_call_timer(call, resend_at, now_j,
242 rxrpc_timer_set_for_resend);
243 spin_unlock_bh(&call->lock);
244 ack_ts = ktime_sub(now, call->acks_latest_ts);
245 if (ktime_to_ns(ack_ts) < call->peer->rtt)
246 goto out;
247 rxrpc_propose_ACK(call, RXRPC_ACK_PING, 0, 0, true, false,
248 rxrpc_propose_ack_ping_for_lost_ack);
249 rxrpc_send_ack_packet(call, true, NULL);
250 goto out;
251 }
252
253 /* Now go through the Tx window and perform the retransmissions. We
254 * have to drop the lock for each send. If an ACK comes in whilst the
255 * lock is dropped, it may clear some of the retransmission markers for
256 * packets that it soft-ACKs.
257 */
258 for (seq = cursor + 1; before_eq(seq, top); seq++) {
259 ix = seq & RXRPC_RXTX_BUFF_MASK;
260 annotation = call->rxtx_annotations[ix];
261 anno_type = annotation & RXRPC_TX_ANNO_MASK;
262 if (anno_type != RXRPC_TX_ANNO_RETRANS)
263 continue;
264
265 skb = call->rxtx_buffer[ix];
266 rxrpc_get_skb(skb, rxrpc_skb_tx_got);
267 spin_unlock_bh(&call->lock);
268
269 if (rxrpc_send_data_packet(call, skb, true) < 0) {
270 rxrpc_free_skb(skb, rxrpc_skb_tx_freed);
271 return;
272 }
273
274 if (rxrpc_is_client_call(call))
275 rxrpc_expose_client_call(call);
276
277 rxrpc_free_skb(skb, rxrpc_skb_tx_freed);
278 spin_lock_bh(&call->lock);
279
280 /* We need to clear the retransmit state, but there are two
281 * things we need to be aware of: A new ACK/NAK might have been
282 * received and the packet might have been hard-ACK'd (in which
283 * case it will no longer be in the buffer).
284 */
285 if (after(seq, call->tx_hard_ack)) {
286 annotation = call->rxtx_annotations[ix];
287 anno_type = annotation & RXRPC_TX_ANNO_MASK;
288 if (anno_type == RXRPC_TX_ANNO_RETRANS ||
289 anno_type == RXRPC_TX_ANNO_NAK) {
290 annotation &= ~RXRPC_TX_ANNO_MASK;
291 annotation |= RXRPC_TX_ANNO_UNACK;
292 }
293 annotation |= RXRPC_TX_ANNO_RESENT;
294 call->rxtx_annotations[ix] = annotation;
295 }
296
297 if (after(call->tx_hard_ack, seq))
298 seq = call->tx_hard_ack;
299 }
300
301out_unlock:
302 spin_unlock_bh(&call->lock);
303out:
304 _leave("");
305}
306
307/*
308 * Handle retransmission and deferred ACK/abort generation.
309 */
310void rxrpc_process_call(struct work_struct *work)
311{
312 struct rxrpc_call *call =
313 container_of(work, struct rxrpc_call, processor);
314 rxrpc_serial_t *send_ack;
315 unsigned long now, next, t;
316
317 rxrpc_see_call(call);
318
319 //printk("\n--------------------\n");
320 _enter("{%d,%s,%lx}",
321 call->debug_id, rxrpc_call_states[call->state], call->events);
322
323recheck_state:
324 if (test_and_clear_bit(RXRPC_CALL_EV_ABORT, &call->events)) {
325 rxrpc_send_abort_packet(call);
326 goto recheck_state;
327 }
328
329 if (call->state == RXRPC_CALL_COMPLETE) {
330 del_timer_sync(&call->timer);
331 rxrpc_notify_socket(call);
332 goto out_put;
333 }
334
335 /* Work out if any timeouts tripped */
336 now = jiffies;
337 t = READ_ONCE(call->expect_rx_by);
338 if (time_after_eq(now, t)) {
339 trace_rxrpc_timer(call, rxrpc_timer_exp_normal, now);
340 set_bit(RXRPC_CALL_EV_EXPIRED, &call->events);
341 }
342
343 t = READ_ONCE(call->expect_req_by);
344 if (call->state == RXRPC_CALL_SERVER_RECV_REQUEST &&
345 time_after_eq(now, t)) {
346 trace_rxrpc_timer(call, rxrpc_timer_exp_idle, now);
347 set_bit(RXRPC_CALL_EV_EXPIRED, &call->events);
348 }
349
350 t = READ_ONCE(call->expect_term_by);
351 if (time_after_eq(now, t)) {
352 trace_rxrpc_timer(call, rxrpc_timer_exp_hard, now);
353 set_bit(RXRPC_CALL_EV_EXPIRED, &call->events);
354 }
355
356 t = READ_ONCE(call->ack_at);
357 if (time_after_eq(now, t)) {
358 trace_rxrpc_timer(call, rxrpc_timer_exp_ack, now);
359 cmpxchg(&call->ack_at, t, now + MAX_JIFFY_OFFSET);
360 set_bit(RXRPC_CALL_EV_ACK, &call->events);
361 }
362
363 t = READ_ONCE(call->ack_lost_at);
364 if (time_after_eq(now, t)) {
365 trace_rxrpc_timer(call, rxrpc_timer_exp_lost_ack, now);
366 cmpxchg(&call->ack_lost_at, t, now + MAX_JIFFY_OFFSET);
367 set_bit(RXRPC_CALL_EV_ACK_LOST, &call->events);
368 }
369
370 t = READ_ONCE(call->keepalive_at);
371 if (time_after_eq(now, t)) {
372 trace_rxrpc_timer(call, rxrpc_timer_exp_keepalive, now);
373 cmpxchg(&call->keepalive_at, t, now + MAX_JIFFY_OFFSET);
374 rxrpc_propose_ACK(call, RXRPC_ACK_PING, 0, 0, true, true,
375 rxrpc_propose_ack_ping_for_keepalive);
376 set_bit(RXRPC_CALL_EV_PING, &call->events);
377 }
378
379 t = READ_ONCE(call->ping_at);
380 if (time_after_eq(now, t)) {
381 trace_rxrpc_timer(call, rxrpc_timer_exp_ping, now);
382 cmpxchg(&call->ping_at, t, now + MAX_JIFFY_OFFSET);
383 set_bit(RXRPC_CALL_EV_PING, &call->events);
384 }
385
386 t = READ_ONCE(call->resend_at);
387 if (time_after_eq(now, t)) {
388 trace_rxrpc_timer(call, rxrpc_timer_exp_resend, now);
389 cmpxchg(&call->resend_at, t, now + MAX_JIFFY_OFFSET);
390 set_bit(RXRPC_CALL_EV_RESEND, &call->events);
391 }
392
393 /* Process events */
394 if (test_and_clear_bit(RXRPC_CALL_EV_EXPIRED, &call->events)) {
395 rxrpc_abort_call("EXP", call, 0, RX_USER_ABORT, -ETIME);
396 set_bit(RXRPC_CALL_EV_ABORT, &call->events);
397 goto recheck_state;
398 }
399
400 send_ack = NULL;
401 if (test_and_clear_bit(RXRPC_CALL_EV_ACK_LOST, &call->events)) {
402 call->acks_lost_top = call->tx_top;
403 rxrpc_propose_ACK(call, RXRPC_ACK_PING, 0, 0, true, false,
404 rxrpc_propose_ack_ping_for_lost_ack);
405 send_ack = &call->acks_lost_ping;
406 }
407
408 if (test_and_clear_bit(RXRPC_CALL_EV_ACK, &call->events) ||
409 send_ack) {
410 if (call->ackr_reason) {
411 rxrpc_send_ack_packet(call, false, send_ack);
412 goto recheck_state;
413 }
414 }
415
416 if (test_and_clear_bit(RXRPC_CALL_EV_PING, &call->events)) {
417 rxrpc_send_ack_packet(call, true, NULL);
418 goto recheck_state;
419 }
420
421 if (test_and_clear_bit(RXRPC_CALL_EV_RESEND, &call->events)) {
422 rxrpc_resend(call, now);
423 goto recheck_state;
424 }
425
426 /* Make sure the timer is restarted */
427 next = call->expect_rx_by;
428
429#define set(T) { t = READ_ONCE(T); if (time_before(t, next)) next = t; }
430
431 set(call->expect_req_by);
432 set(call->expect_term_by);
433 set(call->ack_at);
434 set(call->ack_lost_at);
435 set(call->resend_at);
436 set(call->keepalive_at);
437 set(call->ping_at);
438
439 now = jiffies;
440 if (time_after_eq(now, next))
441 goto recheck_state;
442
443 rxrpc_reduce_call_timer(call, next, now, rxrpc_timer_restart);
444
445 /* other events may have been raised since we started checking */
446 if (call->events && call->state < RXRPC_CALL_COMPLETE) {
447 __rxrpc_queue_call(call);
448 goto out;
449 }
450
451out_put:
452 rxrpc_put_call(call, rxrpc_call_put);
453out:
454 _leave("");
455}
1// SPDX-License-Identifier: GPL-2.0-or-later
2/* Management of Tx window, Tx resend, ACKs and out-of-sequence reception
3 *
4 * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
5 * Written by David Howells (dhowells@redhat.com)
6 */
7
8#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
9
10#include <linux/module.h>
11#include <linux/circ_buf.h>
12#include <linux/net.h>
13#include <linux/skbuff.h>
14#include <linux/slab.h>
15#include <linux/udp.h>
16#include <net/sock.h>
17#include <net/af_rxrpc.h>
18#include "ar-internal.h"
19
20/*
21 * Propose a PING ACK be sent.
22 */
23static void rxrpc_propose_ping(struct rxrpc_call *call,
24 bool immediate, bool background)
25{
26 if (immediate) {
27 if (background &&
28 !test_and_set_bit(RXRPC_CALL_EV_PING, &call->events))
29 rxrpc_queue_call(call);
30 } else {
31 unsigned long now = jiffies;
32 unsigned long ping_at = now + rxrpc_idle_ack_delay;
33
34 if (time_before(ping_at, call->ping_at)) {
35 WRITE_ONCE(call->ping_at, ping_at);
36 rxrpc_reduce_call_timer(call, ping_at, now,
37 rxrpc_timer_set_for_ping);
38 }
39 }
40}
41
42/*
43 * propose an ACK be sent
44 */
45static void __rxrpc_propose_ACK(struct rxrpc_call *call, u8 ack_reason,
46 u32 serial, bool immediate, bool background,
47 enum rxrpc_propose_ack_trace why)
48{
49 enum rxrpc_propose_ack_outcome outcome = rxrpc_propose_ack_use;
50 unsigned long expiry = rxrpc_soft_ack_delay;
51 s8 prior = rxrpc_ack_priority[ack_reason];
52
53 /* Pings are handled specially because we don't want to accidentally
54 * lose a ping response by subsuming it into a ping.
55 */
56 if (ack_reason == RXRPC_ACK_PING) {
57 rxrpc_propose_ping(call, immediate, background);
58 goto trace;
59 }
60
61 /* Update DELAY, IDLE, REQUESTED and PING_RESPONSE ACK serial
62 * numbers, but we don't alter the timeout.
63 */
64 _debug("prior %u %u vs %u %u",
65 ack_reason, prior,
66 call->ackr_reason, rxrpc_ack_priority[call->ackr_reason]);
67 if (ack_reason == call->ackr_reason) {
68 if (RXRPC_ACK_UPDATEABLE & (1 << ack_reason)) {
69 outcome = rxrpc_propose_ack_update;
70 call->ackr_serial = serial;
71 }
72 if (!immediate)
73 goto trace;
74 } else if (prior > rxrpc_ack_priority[call->ackr_reason]) {
75 call->ackr_reason = ack_reason;
76 call->ackr_serial = serial;
77 } else {
78 outcome = rxrpc_propose_ack_subsume;
79 }
80
81 switch (ack_reason) {
82 case RXRPC_ACK_REQUESTED:
83 if (rxrpc_requested_ack_delay < expiry)
84 expiry = rxrpc_requested_ack_delay;
85 if (serial == 1)
86 immediate = false;
87 break;
88
89 case RXRPC_ACK_DELAY:
90 if (rxrpc_soft_ack_delay < expiry)
91 expiry = rxrpc_soft_ack_delay;
92 break;
93
94 case RXRPC_ACK_IDLE:
95 if (rxrpc_idle_ack_delay < expiry)
96 expiry = rxrpc_idle_ack_delay;
97 break;
98
99 default:
100 immediate = true;
101 break;
102 }
103
104 if (test_bit(RXRPC_CALL_EV_ACK, &call->events)) {
105 _debug("already scheduled");
106 } else if (immediate || expiry == 0) {
107 _debug("immediate ACK %lx", call->events);
108 if (!test_and_set_bit(RXRPC_CALL_EV_ACK, &call->events) &&
109 background)
110 rxrpc_queue_call(call);
111 } else {
112 unsigned long now = jiffies, ack_at;
113
114 if (call->peer->rtt_usage > 0)
115 ack_at = nsecs_to_jiffies(call->peer->rtt);
116 else
117 ack_at = expiry;
118
119 ack_at += READ_ONCE(call->tx_backoff);
120 ack_at += now;
121 if (time_before(ack_at, call->ack_at)) {
122 WRITE_ONCE(call->ack_at, ack_at);
123 rxrpc_reduce_call_timer(call, ack_at, now,
124 rxrpc_timer_set_for_ack);
125 }
126 }
127
128trace:
129 trace_rxrpc_propose_ack(call, why, ack_reason, serial, immediate,
130 background, outcome);
131}
132
133/*
134 * propose an ACK be sent, locking the call structure
135 */
136void rxrpc_propose_ACK(struct rxrpc_call *call, u8 ack_reason,
137 u32 serial, bool immediate, bool background,
138 enum rxrpc_propose_ack_trace why)
139{
140 spin_lock_bh(&call->lock);
141 __rxrpc_propose_ACK(call, ack_reason, serial,
142 immediate, background, why);
143 spin_unlock_bh(&call->lock);
144}
145
146/*
147 * Handle congestion being detected by the retransmit timeout.
148 */
149static void rxrpc_congestion_timeout(struct rxrpc_call *call)
150{
151 set_bit(RXRPC_CALL_RETRANS_TIMEOUT, &call->flags);
152}
153
154/*
155 * Perform retransmission of NAK'd and unack'd packets.
156 */
157static void rxrpc_resend(struct rxrpc_call *call, unsigned long now_j)
158{
159 struct sk_buff *skb;
160 unsigned long resend_at;
161 rxrpc_seq_t cursor, seq, top;
162 ktime_t now, max_age, oldest, ack_ts, timeout, min_timeo;
163 int ix;
164 u8 annotation, anno_type, retrans = 0, unacked = 0;
165
166 _enter("{%d,%d}", call->tx_hard_ack, call->tx_top);
167
168 if (call->peer->rtt_usage > 1)
169 timeout = ns_to_ktime(call->peer->rtt * 3 / 2);
170 else
171 timeout = ms_to_ktime(rxrpc_resend_timeout);
172 min_timeo = ns_to_ktime((1000000000 / HZ) * 4);
173 if (ktime_before(timeout, min_timeo))
174 timeout = min_timeo;
175
176 now = ktime_get_real();
177 max_age = ktime_sub(now, timeout);
178
179 spin_lock_bh(&call->lock);
180
181 cursor = call->tx_hard_ack;
182 top = call->tx_top;
183 ASSERT(before_eq(cursor, top));
184 if (cursor == top)
185 goto out_unlock;
186
187 /* Scan the packet list without dropping the lock and decide which of
188 * the packets in the Tx buffer we're going to resend and what the new
189 * resend timeout will be.
190 */
191 trace_rxrpc_resend(call, (cursor + 1) & RXRPC_RXTX_BUFF_MASK);
192 oldest = now;
193 for (seq = cursor + 1; before_eq(seq, top); seq++) {
194 ix = seq & RXRPC_RXTX_BUFF_MASK;
195 annotation = call->rxtx_annotations[ix];
196 anno_type = annotation & RXRPC_TX_ANNO_MASK;
197 annotation &= ~RXRPC_TX_ANNO_MASK;
198 if (anno_type == RXRPC_TX_ANNO_ACK)
199 continue;
200
201 skb = call->rxtx_buffer[ix];
202 rxrpc_see_skb(skb, rxrpc_skb_seen);
203
204 if (anno_type == RXRPC_TX_ANNO_UNACK) {
205 if (ktime_after(skb->tstamp, max_age)) {
206 if (ktime_before(skb->tstamp, oldest))
207 oldest = skb->tstamp;
208 continue;
209 }
210 if (!(annotation & RXRPC_TX_ANNO_RESENT))
211 unacked++;
212 }
213
214 /* Okay, we need to retransmit a packet. */
215 call->rxtx_annotations[ix] = RXRPC_TX_ANNO_RETRANS | annotation;
216 retrans++;
217 trace_rxrpc_retransmit(call, seq, annotation | anno_type,
218 ktime_to_ns(ktime_sub(skb->tstamp, max_age)));
219 }
220
221 resend_at = nsecs_to_jiffies(ktime_to_ns(ktime_sub(now, oldest)));
222 resend_at += jiffies + rxrpc_resend_timeout;
223 WRITE_ONCE(call->resend_at, resend_at);
224
225 if (unacked)
226 rxrpc_congestion_timeout(call);
227
228 /* If there was nothing that needed retransmission then it's likely
229 * that an ACK got lost somewhere. Send a ping to find out instead of
230 * retransmitting data.
231 */
232 if (!retrans) {
233 rxrpc_reduce_call_timer(call, resend_at, now_j,
234 rxrpc_timer_set_for_resend);
235 spin_unlock_bh(&call->lock);
236 ack_ts = ktime_sub(now, call->acks_latest_ts);
237 if (ktime_to_ns(ack_ts) < call->peer->rtt)
238 goto out;
239 rxrpc_propose_ACK(call, RXRPC_ACK_PING, 0, true, false,
240 rxrpc_propose_ack_ping_for_lost_ack);
241 rxrpc_send_ack_packet(call, true, NULL);
242 goto out;
243 }
244
245 /* Now go through the Tx window and perform the retransmissions. We
246 * have to drop the lock for each send. If an ACK comes in whilst the
247 * lock is dropped, it may clear some of the retransmission markers for
248 * packets that it soft-ACKs.
249 */
250 for (seq = cursor + 1; before_eq(seq, top); seq++) {
251 ix = seq & RXRPC_RXTX_BUFF_MASK;
252 annotation = call->rxtx_annotations[ix];
253 anno_type = annotation & RXRPC_TX_ANNO_MASK;
254 if (anno_type != RXRPC_TX_ANNO_RETRANS)
255 continue;
256
257 skb = call->rxtx_buffer[ix];
258 rxrpc_get_skb(skb, rxrpc_skb_got);
259 spin_unlock_bh(&call->lock);
260
261 if (rxrpc_send_data_packet(call, skb, true) < 0) {
262 rxrpc_free_skb(skb, rxrpc_skb_freed);
263 return;
264 }
265
266 if (rxrpc_is_client_call(call))
267 rxrpc_expose_client_call(call);
268
269 rxrpc_free_skb(skb, rxrpc_skb_freed);
270 spin_lock_bh(&call->lock);
271
272 /* We need to clear the retransmit state, but there are two
273 * things we need to be aware of: A new ACK/NAK might have been
274 * received and the packet might have been hard-ACK'd (in which
275 * case it will no longer be in the buffer).
276 */
277 if (after(seq, call->tx_hard_ack)) {
278 annotation = call->rxtx_annotations[ix];
279 anno_type = annotation & RXRPC_TX_ANNO_MASK;
280 if (anno_type == RXRPC_TX_ANNO_RETRANS ||
281 anno_type == RXRPC_TX_ANNO_NAK) {
282 annotation &= ~RXRPC_TX_ANNO_MASK;
283 annotation |= RXRPC_TX_ANNO_UNACK;
284 }
285 annotation |= RXRPC_TX_ANNO_RESENT;
286 call->rxtx_annotations[ix] = annotation;
287 }
288
289 if (after(call->tx_hard_ack, seq))
290 seq = call->tx_hard_ack;
291 }
292
293out_unlock:
294 spin_unlock_bh(&call->lock);
295out:
296 _leave("");
297}
298
299/*
300 * Handle retransmission and deferred ACK/abort generation.
301 */
302void rxrpc_process_call(struct work_struct *work)
303{
304 struct rxrpc_call *call =
305 container_of(work, struct rxrpc_call, processor);
306 rxrpc_serial_t *send_ack;
307 unsigned long now, next, t;
308 unsigned int iterations = 0;
309
310 rxrpc_see_call(call);
311
312 //printk("\n--------------------\n");
313 _enter("{%d,%s,%lx}",
314 call->debug_id, rxrpc_call_states[call->state], call->events);
315
316recheck_state:
317 /* Limit the number of times we do this before returning to the manager */
318 iterations++;
319 if (iterations > 5)
320 goto requeue;
321
322 if (test_and_clear_bit(RXRPC_CALL_EV_ABORT, &call->events)) {
323 rxrpc_send_abort_packet(call);
324 goto recheck_state;
325 }
326
327 if (call->state == RXRPC_CALL_COMPLETE) {
328 del_timer_sync(&call->timer);
329 rxrpc_notify_socket(call);
330 goto out_put;
331 }
332
333 /* Work out if any timeouts tripped */
334 now = jiffies;
335 t = READ_ONCE(call->expect_rx_by);
336 if (time_after_eq(now, t)) {
337 trace_rxrpc_timer(call, rxrpc_timer_exp_normal, now);
338 set_bit(RXRPC_CALL_EV_EXPIRED, &call->events);
339 }
340
341 t = READ_ONCE(call->expect_req_by);
342 if (call->state == RXRPC_CALL_SERVER_RECV_REQUEST &&
343 time_after_eq(now, t)) {
344 trace_rxrpc_timer(call, rxrpc_timer_exp_idle, now);
345 set_bit(RXRPC_CALL_EV_EXPIRED, &call->events);
346 }
347
348 t = READ_ONCE(call->expect_term_by);
349 if (time_after_eq(now, t)) {
350 trace_rxrpc_timer(call, rxrpc_timer_exp_hard, now);
351 set_bit(RXRPC_CALL_EV_EXPIRED, &call->events);
352 }
353
354 t = READ_ONCE(call->ack_at);
355 if (time_after_eq(now, t)) {
356 trace_rxrpc_timer(call, rxrpc_timer_exp_ack, now);
357 cmpxchg(&call->ack_at, t, now + MAX_JIFFY_OFFSET);
358 set_bit(RXRPC_CALL_EV_ACK, &call->events);
359 }
360
361 t = READ_ONCE(call->ack_lost_at);
362 if (time_after_eq(now, t)) {
363 trace_rxrpc_timer(call, rxrpc_timer_exp_lost_ack, now);
364 cmpxchg(&call->ack_lost_at, t, now + MAX_JIFFY_OFFSET);
365 set_bit(RXRPC_CALL_EV_ACK_LOST, &call->events);
366 }
367
368 t = READ_ONCE(call->keepalive_at);
369 if (time_after_eq(now, t)) {
370 trace_rxrpc_timer(call, rxrpc_timer_exp_keepalive, now);
371 cmpxchg(&call->keepalive_at, t, now + MAX_JIFFY_OFFSET);
372 rxrpc_propose_ACK(call, RXRPC_ACK_PING, 0, true, true,
373 rxrpc_propose_ack_ping_for_keepalive);
374 set_bit(RXRPC_CALL_EV_PING, &call->events);
375 }
376
377 t = READ_ONCE(call->ping_at);
378 if (time_after_eq(now, t)) {
379 trace_rxrpc_timer(call, rxrpc_timer_exp_ping, now);
380 cmpxchg(&call->ping_at, t, now + MAX_JIFFY_OFFSET);
381 set_bit(RXRPC_CALL_EV_PING, &call->events);
382 }
383
384 t = READ_ONCE(call->resend_at);
385 if (time_after_eq(now, t)) {
386 trace_rxrpc_timer(call, rxrpc_timer_exp_resend, now);
387 cmpxchg(&call->resend_at, t, now + MAX_JIFFY_OFFSET);
388 set_bit(RXRPC_CALL_EV_RESEND, &call->events);
389 }
390
391 /* Process events */
392 if (test_and_clear_bit(RXRPC_CALL_EV_EXPIRED, &call->events)) {
393 if (test_bit(RXRPC_CALL_RX_HEARD, &call->flags) &&
394 (int)call->conn->hi_serial - (int)call->rx_serial > 0) {
395 trace_rxrpc_call_reset(call);
396 rxrpc_abort_call("EXP", call, 0, RX_USER_ABORT, -ECONNRESET);
397 } else {
398 rxrpc_abort_call("EXP", call, 0, RX_USER_ABORT, -ETIME);
399 }
400 set_bit(RXRPC_CALL_EV_ABORT, &call->events);
401 goto recheck_state;
402 }
403
404 send_ack = NULL;
405 if (test_and_clear_bit(RXRPC_CALL_EV_ACK_LOST, &call->events)) {
406 call->acks_lost_top = call->tx_top;
407 rxrpc_propose_ACK(call, RXRPC_ACK_PING, 0, true, false,
408 rxrpc_propose_ack_ping_for_lost_ack);
409 send_ack = &call->acks_lost_ping;
410 }
411
412 if (test_and_clear_bit(RXRPC_CALL_EV_ACK, &call->events) ||
413 send_ack) {
414 if (call->ackr_reason) {
415 rxrpc_send_ack_packet(call, false, send_ack);
416 goto recheck_state;
417 }
418 }
419
420 if (test_and_clear_bit(RXRPC_CALL_EV_PING, &call->events)) {
421 rxrpc_send_ack_packet(call, true, NULL);
422 goto recheck_state;
423 }
424
425 if (test_and_clear_bit(RXRPC_CALL_EV_RESEND, &call->events)) {
426 rxrpc_resend(call, now);
427 goto recheck_state;
428 }
429
430 /* Make sure the timer is restarted */
431 next = call->expect_rx_by;
432
433#define set(T) { t = READ_ONCE(T); if (time_before(t, next)) next = t; }
434
435 set(call->expect_req_by);
436 set(call->expect_term_by);
437 set(call->ack_at);
438 set(call->ack_lost_at);
439 set(call->resend_at);
440 set(call->keepalive_at);
441 set(call->ping_at);
442
443 now = jiffies;
444 if (time_after_eq(now, next))
445 goto recheck_state;
446
447 rxrpc_reduce_call_timer(call, next, now, rxrpc_timer_restart);
448
449 /* other events may have been raised since we started checking */
450 if (call->events && call->state < RXRPC_CALL_COMPLETE)
451 goto requeue;
452
453out_put:
454 rxrpc_put_call(call, rxrpc_call_put);
455out:
456 _leave("");
457 return;
458
459requeue:
460 __rxrpc_queue_call(call);
461 goto out;
462}