Merge remote-tracking branch 'iommu/next'
[deliverable/linux.git] / net / rxrpc / call_event.c
CommitLineData
17926a79
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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
9b6d5398
JP
12#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
13
17926a79
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14#include <linux/module.h>
15#include <linux/circ_buf.h>
16#include <linux/net.h>
17#include <linux/skbuff.h>
5a0e3ad6 18#include <linux/slab.h>
17926a79
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19#include <linux/udp.h>
20#include <net/sock.h>
21#include <net/af_rxrpc.h>
22#include "ar-internal.h"
23
17926a79 24/*
248f219c 25 * Set the timer
17926a79 26 */
248f219c 27static void rxrpc_set_timer(struct rxrpc_call *call)
17926a79 28{
248f219c 29 unsigned long t, now = jiffies;
17926a79 30
248f219c
DH
31 _enter("{%ld,%ld,%ld:%ld}",
32 call->ack_at - now, call->resend_at - now, call->expire_at - now,
33 call->timer.expires - now);
34
35 read_lock_bh(&call->state_lock);
17926a79 36
248f219c
DH
37 if (call->state < RXRPC_CALL_COMPLETE) {
38 t = call->ack_at;
39 if (time_before(call->resend_at, t))
40 t = call->resend_at;
41 if (time_before(call->expire_at, t))
42 t = call->expire_at;
43 if (!timer_pending(&call->timer) ||
44 time_before(t, call->timer.expires)) {
45 _debug("set timer %ld", t - now);
46 mod_timer(&call->timer, t);
17926a79 47 }
17926a79 48 }
17926a79
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49 read_unlock_bh(&call->state_lock);
50}
51
52/*
248f219c 53 * propose an ACK be sent
17926a79 54 */
248f219c
DH
55static void __rxrpc_propose_ACK(struct rxrpc_call *call, u8 ack_reason,
56 u16 skew, u32 serial, bool immediate,
57 bool background)
17926a79 58{
248f219c 59 unsigned long now, ack_at, expiry = rxrpc_soft_ack_delay;
17926a79
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60 s8 prior = rxrpc_ack_priority[ack_reason];
61
248f219c
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62 _enter("{%d},%s,%%%x,%u",
63 call->debug_id, rxrpc_acks(ack_reason), serial, immediate);
17926a79 64
248f219c
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65 /* Update DELAY, IDLE, REQUESTED and PING_RESPONSE ACK serial
66 * numbers, but we don't alter the timeout.
67 */
68 _debug("prior %u %u vs %u %u",
69 ack_reason, prior,
70 call->ackr_reason, rxrpc_ack_priority[call->ackr_reason]);
71 if (ack_reason == call->ackr_reason) {
72 if (RXRPC_ACK_UPDATEABLE & (1 << ack_reason)) {
73 call->ackr_serial = serial;
74 call->ackr_skew = skew;
17926a79 75 }
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DH
76 if (!immediate)
77 return;
78 } else if (prior > rxrpc_ack_priority[call->ackr_reason]) {
79 call->ackr_reason = ack_reason;
80 call->ackr_serial = serial;
81 call->ackr_skew = skew;
17926a79
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82 }
83
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84 switch (ack_reason) {
85 case RXRPC_ACK_REQUESTED:
86 if (rxrpc_requested_ack_delay < expiry)
87 expiry = rxrpc_requested_ack_delay;
88 if (serial == 1)
89 immediate = false;
90 break;
17926a79 91
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92 case RXRPC_ACK_DELAY:
93 if (rxrpc_soft_ack_delay < expiry)
94 expiry = rxrpc_soft_ack_delay;
95 break;
17926a79 96
248f219c
DH
97 case RXRPC_ACK_IDLE:
98 if (rxrpc_soft_ack_delay < expiry)
99 expiry = rxrpc_idle_ack_delay;
100 break;
17926a79 101
248f219c
DH
102 default:
103 immediate = true;
104 break;
17926a79
DH
105 }
106
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DH
107 now = jiffies;
108 if (test_bit(RXRPC_CALL_EV_ACK, &call->events)) {
109 _debug("already scheduled");
110 } else if (immediate || expiry == 0) {
111 _debug("immediate ACK %lx", call->events);
112 if (!test_and_set_bit(RXRPC_CALL_EV_ACK, &call->events) &&
113 background)
114 rxrpc_queue_call(call);
115 } else {
116 ack_at = now + expiry;
117 _debug("deferred ACK %ld < %ld", expiry, call->ack_at - now);
118 if (time_before(ack_at, call->ack_at)) {
119 call->ack_at = ack_at;
120 rxrpc_set_timer(call);
17926a79
DH
121 }
122 }
17926a79
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123}
124
125/*
248f219c 126 * propose an ACK be sent, locking the call structure
17926a79 127 */
248f219c
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128void rxrpc_propose_ACK(struct rxrpc_call *call, u8 ack_reason,
129 u16 skew, u32 serial, bool immediate, bool background)
17926a79 130{
248f219c
DH
131 spin_lock_bh(&call->lock);
132 __rxrpc_propose_ACK(call, ack_reason, skew, serial,
133 immediate, background);
134 spin_unlock_bh(&call->lock);
17926a79
DH
135}
136
137/*
248f219c 138 * Perform retransmission of NAK'd and unack'd packets.
17926a79 139 */
248f219c 140static void rxrpc_resend(struct rxrpc_call *call)
17926a79 141{
248f219c 142 struct rxrpc_wire_header *whdr;
17926a79
DH
143 struct rxrpc_skb_priv *sp;
144 struct sk_buff *skb;
248f219c
DH
145 rxrpc_seq_t cursor, seq, top;
146 unsigned long resend_at, now;
147 int ix;
148 u8 annotation;
17926a79 149
248f219c 150 _enter("{%d,%d}", call->tx_hard_ack, call->tx_top);
17926a79
DH
151
152 spin_lock_bh(&call->lock);
153
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154 cursor = call->tx_hard_ack;
155 top = call->tx_top;
156 ASSERT(before_eq(cursor, top));
157 if (cursor == top)
158 goto out_unlock;
159
160 /* Scan the packet list without dropping the lock and decide which of
161 * the packets in the Tx buffer we're going to resend and what the new
162 * resend timeout will be.
163 */
164 now = jiffies;
165 resend_at = now + rxrpc_resend_timeout;
166 seq = cursor + 1;
167 do {
168 ix = seq & RXRPC_RXTX_BUFF_MASK;
169 annotation = call->rxtx_annotations[ix];
170 if (annotation == RXRPC_TX_ANNO_ACK)
171 continue;
17926a79 172
248f219c 173 skb = call->rxtx_buffer[ix];
df844fd4 174 rxrpc_see_skb(skb);
17926a79
DH
175 sp = rxrpc_skb(skb);
176
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DH
177 if (annotation == RXRPC_TX_ANNO_UNACK) {
178 if (time_after(sp->resend_at, now)) {
179 if (time_before(sp->resend_at, resend_at))
180 resend_at = sp->resend_at;
181 continue;
33c40e24 182 }
17926a79 183 }
17926a79 184
248f219c
DH
185 /* Okay, we need to retransmit a packet. */
186 call->rxtx_annotations[ix] = RXRPC_TX_ANNO_RETRANS;
187 seq++;
188 } while (before_eq(seq, top));
189
190 call->resend_at = resend_at;
191
192 /* Now go through the Tx window and perform the retransmissions. We
193 * have to drop the lock for each send. If an ACK comes in whilst the
194 * lock is dropped, it may clear some of the retransmission markers for
195 * packets that it soft-ACKs.
196 */
197 seq = cursor + 1;
198 do {
199 ix = seq & RXRPC_RXTX_BUFF_MASK;
200 annotation = call->rxtx_annotations[ix];
201 if (annotation != RXRPC_TX_ANNO_RETRANS)
202 continue;
17926a79 203
248f219c
DH
204 skb = call->rxtx_buffer[ix];
205 rxrpc_get_skb(skb);
17926a79 206 spin_unlock_bh(&call->lock);
248f219c 207 sp = rxrpc_skb(skb);
17926a79 208
248f219c
DH
209 /* Each Tx packet needs a new serial number */
210 sp->hdr.serial = atomic_inc_return(&call->conn->serial);
17926a79 211
248f219c
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212 whdr = (struct rxrpc_wire_header *)skb->head;
213 whdr->serial = htonl(sp->hdr.serial);
17926a79 214
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DH
215 if (rxrpc_send_data_packet(call->conn, skb) < 0) {
216 call->resend_at = now + 2;
217 rxrpc_free_skb(skb);
218 return;
219 }
17926a79 220
248f219c
DH
221 if (rxrpc_is_client_call(call))
222 rxrpc_expose_client_call(call);
223 sp->resend_at = now + rxrpc_resend_timeout;
17926a79 224
248f219c 225 rxrpc_free_skb(skb);
17926a79 226 spin_lock_bh(&call->lock);
17926a79 227
248f219c
DH
228 /* We need to clear the retransmit state, but there are two
229 * things we need to be aware of: A new ACK/NAK might have been
230 * received and the packet might have been hard-ACK'd (in which
231 * case it will no longer be in the buffer).
232 */
233 if (after(seq, call->tx_hard_ack) &&
234 (call->rxtx_annotations[ix] == RXRPC_TX_ANNO_RETRANS ||
235 call->rxtx_annotations[ix] == RXRPC_TX_ANNO_NAK))
236 call->rxtx_annotations[ix] = RXRPC_TX_ANNO_UNACK;
237
238 if (after(call->tx_hard_ack, seq))
239 seq = call->tx_hard_ack;
240 seq++;
241 } while (before_eq(seq, top));
242
243out_unlock:
244 spin_unlock_bh(&call->lock);
245 _leave("");
17926a79
DH
246}
247
248/*
248f219c 249 * Handle retransmission and deferred ACK/abort generation.
17926a79
DH
250 */
251void rxrpc_process_call(struct work_struct *work)
252{
253 struct rxrpc_call *call =
254 container_of(work, struct rxrpc_call, processor);
248f219c 255 unsigned long now;
17926a79 256
e34d4234
DH
257 rxrpc_see_call(call);
258
17926a79 259 //printk("\n--------------------\n");
248f219c
DH
260 _enter("{%d,%s,%lx}",
261 call->debug_id, rxrpc_call_states[call->state], call->events);
17926a79 262
248f219c
DH
263recheck_state:
264 if (test_and_clear_bit(RXRPC_CALL_EV_ABORT, &call->events)) {
265 rxrpc_send_call_packet(call, RXRPC_PACKET_TYPE_ABORT);
266 goto recheck_state;
17926a79
DH
267 }
268
248f219c
DH
269 if (call->state == RXRPC_CALL_COMPLETE) {
270 del_timer_sync(&call->timer);
271 goto out_put;
17926a79
DH
272 }
273
248f219c
DH
274 now = jiffies;
275 if (time_after_eq(now, call->expire_at)) {
5a42976d 276 rxrpc_abort_call("EXP", call, 0, RX_CALL_TIMEOUT, ETIME);
248f219c 277 set_bit(RXRPC_CALL_EV_ABORT, &call->events);
17926a79
DH
278 }
279
248f219c
DH
280 if (test_and_clear_bit(RXRPC_CALL_EV_ACK, &call->events) ||
281 time_after_eq(now, call->ack_at)) {
282 call->ack_at = call->expire_at;
283 if (call->ackr_reason) {
284 rxrpc_send_call_packet(call, RXRPC_PACKET_TYPE_ACK);
285 goto recheck_state;
17926a79
DH
286 }
287 }
288
248f219c
DH
289 if (test_and_clear_bit(RXRPC_CALL_EV_RESEND, &call->events) ||
290 time_after_eq(now, call->resend_at)) {
17926a79 291 rxrpc_resend(call);
248f219c 292 goto recheck_state;
17926a79
DH
293 }
294
248f219c 295 rxrpc_set_timer(call);
17926a79
DH
296
297 /* other events may have been raised since we started checking */
248f219c 298 if (call->events && call->state < RXRPC_CALL_COMPLETE) {
8d94aa38 299 __rxrpc_queue_call(call);
248f219c 300 goto out;
17926a79
DH
301 }
302
248f219c
DH
303out_put:
304 rxrpc_put_call(call, rxrpc_call_put);
305out:
17926a79 306 _leave("");
17926a79 307}
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