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objtool: Skip unreachable warnings for GCC 4.4 and older
[linux-2.6/btrfs-unstable.git] / net / rxrpc / input.c
blobe56e23ed2229c8568f839cdda32ade1ade0eaee7
1 /* RxRPC packet reception
2 *
3 * Copyright (C) 2007, 2016 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/net.h>
16 #include <linux/skbuff.h>
17 #include <linux/errqueue.h>
18 #include <linux/udp.h>
19 #include <linux/in.h>
20 #include <linux/in6.h>
21 #include <linux/icmp.h>
22 #include <linux/gfp.h>
23 #include <net/sock.h>
24 #include <net/af_rxrpc.h>
25 #include <net/ip.h>
26 #include <net/udp.h>
27 #include <net/net_namespace.h>
28 #include "ar-internal.h"
29
30 static void rxrpc_proto_abort(const char *why,
31 struct rxrpc_call *call, rxrpc_seq_t seq)
32 {
33 if (rxrpc_abort_call(why, call, seq, RX_PROTOCOL_ERROR, -EBADMSG)) {
34 set_bit(RXRPC_CALL_EV_ABORT, &call->events);
35 rxrpc_queue_call(call);
36 }
37 }
38
39 /*
40 * Do TCP-style congestion management [RFC 5681].
41 */
42 static void rxrpc_congestion_management(struct rxrpc_call *call,
43 struct sk_buff *skb,
44 struct rxrpc_ack_summary *summary,
45 rxrpc_serial_t acked_serial)
46 {
47 enum rxrpc_congest_change change = rxrpc_cong_no_change;
48 unsigned int cumulative_acks = call->cong_cumul_acks;
49 unsigned int cwnd = call->cong_cwnd;
50 bool resend = false;
51
52 summary->flight_size =
53 (call->tx_top - call->tx_hard_ack) - summary->nr_acks;
54
55 if (test_and_clear_bit(RXRPC_CALL_RETRANS_TIMEOUT, &call->flags)) {
56 summary->retrans_timeo = true;
57 call->cong_ssthresh = max_t(unsigned int,
58 summary->flight_size / 2, 2);
59 cwnd = 1;
60 if (cwnd >= call->cong_ssthresh &&
61 call->cong_mode == RXRPC_CALL_SLOW_START) {
62 call->cong_mode = RXRPC_CALL_CONGEST_AVOIDANCE;
63 call->cong_tstamp = skb->tstamp;
64 cumulative_acks = 0;
65 }
66 }
67
68 cumulative_acks += summary->nr_new_acks;
69 cumulative_acks += summary->nr_rot_new_acks;
70 if (cumulative_acks > 255)
71 cumulative_acks = 255;
72
73 summary->mode = call->cong_mode;
74 summary->cwnd = call->cong_cwnd;
75 summary->ssthresh = call->cong_ssthresh;
76 summary->cumulative_acks = cumulative_acks;
77 summary->dup_acks = call->cong_dup_acks;
78
79 switch (call->cong_mode) {
80 case RXRPC_CALL_SLOW_START:
81 if (summary->nr_nacks > 0)
82 goto packet_loss_detected;
83 if (summary->cumulative_acks > 0)
84 cwnd += 1;
85 if (cwnd >= call->cong_ssthresh) {
86 call->cong_mode = RXRPC_CALL_CONGEST_AVOIDANCE;
87 call->cong_tstamp = skb->tstamp;
88 }
89 goto out;
90
91 case RXRPC_CALL_CONGEST_AVOIDANCE:
92 if (summary->nr_nacks > 0)
93 goto packet_loss_detected;
94
95 /* We analyse the number of packets that get ACK'd per RTT
96 * period and increase the window if we managed to fill it.
97 */
98 if (call->peer->rtt_usage == 0)
99 goto out;
100 if (ktime_before(skb->tstamp,
101 ktime_add_ns(call->cong_tstamp,
102 call->peer->rtt)))
103 goto out_no_clear_ca;
104 change = rxrpc_cong_rtt_window_end;
105 call->cong_tstamp = skb->tstamp;
106 if (cumulative_acks >= cwnd)
107 cwnd++;
108 goto out;
109
110 case RXRPC_CALL_PACKET_LOSS:
111 if (summary->nr_nacks == 0)
112 goto resume_normality;
113
114 if (summary->new_low_nack) {
115 change = rxrpc_cong_new_low_nack;
116 call->cong_dup_acks = 1;
117 if (call->cong_extra > 1)
118 call->cong_extra = 1;
119 goto send_extra_data;
120 }
121
122 call->cong_dup_acks++;
123 if (call->cong_dup_acks < 3)
124 goto send_extra_data;
125
126 change = rxrpc_cong_begin_retransmission;
127 call->cong_mode = RXRPC_CALL_FAST_RETRANSMIT;
128 call->cong_ssthresh = max_t(unsigned int,
129 summary->flight_size / 2, 2);
130 cwnd = call->cong_ssthresh + 3;
131 call->cong_extra = 0;
132 call->cong_dup_acks = 0;
133 resend = true;
134 goto out;
135
136 case RXRPC_CALL_FAST_RETRANSMIT:
137 if (!summary->new_low_nack) {
138 if (summary->nr_new_acks == 0)
139 cwnd += 1;
140 call->cong_dup_acks++;
141 if (call->cong_dup_acks == 2) {
142 change = rxrpc_cong_retransmit_again;
143 call->cong_dup_acks = 0;
144 resend = true;
145 }
146 } else {
147 change = rxrpc_cong_progress;
148 cwnd = call->cong_ssthresh;
149 if (summary->nr_nacks == 0)
150 goto resume_normality;
151 }
152 goto out;
153
154 default:
155 BUG();
156 goto out;
157 }
158
159 resume_normality:
160 change = rxrpc_cong_cleared_nacks;
161 call->cong_dup_acks = 0;
162 call->cong_extra = 0;
163 call->cong_tstamp = skb->tstamp;
164 if (cwnd < call->cong_ssthresh)
165 call->cong_mode = RXRPC_CALL_SLOW_START;
166 else
167 call->cong_mode = RXRPC_CALL_CONGEST_AVOIDANCE;
168 out:
169 cumulative_acks = 0;
170 out_no_clear_ca:
171 if (cwnd >= RXRPC_RXTX_BUFF_SIZE - 1)
172 cwnd = RXRPC_RXTX_BUFF_SIZE - 1;
173 call->cong_cwnd = cwnd;
174 call->cong_cumul_acks = cumulative_acks;
175 trace_rxrpc_congest(call, summary, acked_serial, change);
176 if (resend && !test_and_set_bit(RXRPC_CALL_EV_RESEND, &call->events))
177 rxrpc_queue_call(call);
178 return;
179
180 packet_loss_detected:
181 change = rxrpc_cong_saw_nack;
182 call->cong_mode = RXRPC_CALL_PACKET_LOSS;
183 call->cong_dup_acks = 0;
184 goto send_extra_data;
185
186 send_extra_data:
187 /* Send some previously unsent DATA if we have some to advance the ACK
188 * state.
189 */
190 if (call->rxtx_annotations[call->tx_top & RXRPC_RXTX_BUFF_MASK] &
191 RXRPC_TX_ANNO_LAST ||
192 summary->nr_acks != call->tx_top - call->tx_hard_ack) {
193 call->cong_extra++;
194 wake_up(&call->waitq);
195 }
196 goto out_no_clear_ca;
197 }
198
199 /*
200 * Ping the other end to fill our RTT cache and to retrieve the rwind
201 * and MTU parameters.
202 */
203 static void rxrpc_send_ping(struct rxrpc_call *call, struct sk_buff *skb,
204 int skew)
205 {
206 struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
207 ktime_t now = skb->tstamp;
208
209 if (call->peer->rtt_usage < 3 ||
210 ktime_before(ktime_add_ms(call->peer->rtt_last_req, 1000), now))
211 rxrpc_propose_ACK(call, RXRPC_ACK_PING, skew, sp->hdr.serial,
212 true, true,
213 rxrpc_propose_ack_ping_for_params);
214 }
215
216 /*
217 * Apply a hard ACK by advancing the Tx window.
218 */
219 static void rxrpc_rotate_tx_window(struct rxrpc_call *call, rxrpc_seq_t to,
220 struct rxrpc_ack_summary *summary)
221 {
222 struct sk_buff *skb, *list = NULL;
223 int ix;
224 u8 annotation;
225
226 if (call->acks_lowest_nak == call->tx_hard_ack) {
227 call->acks_lowest_nak = to;
228 } else if (before_eq(call->acks_lowest_nak, to)) {
229 summary->new_low_nack = true;
230 call->acks_lowest_nak = to;
231 }
232
233 spin_lock(&call->lock);
234
235 while (before(call->tx_hard_ack, to)) {
236 call->tx_hard_ack++;
237 ix = call->tx_hard_ack & RXRPC_RXTX_BUFF_MASK;
238 skb = call->rxtx_buffer[ix];
239 annotation = call->rxtx_annotations[ix];
240 rxrpc_see_skb(skb, rxrpc_skb_tx_rotated);
241 call->rxtx_buffer[ix] = NULL;
242 call->rxtx_annotations[ix] = 0;
243 skb->next = list;
244 list = skb;
245
246 if (annotation & RXRPC_TX_ANNO_LAST)
247 set_bit(RXRPC_CALL_TX_LAST, &call->flags);
248 if ((annotation & RXRPC_TX_ANNO_MASK) != RXRPC_TX_ANNO_ACK)
249 summary->nr_rot_new_acks++;
250 }
251
252 spin_unlock(&call->lock);
253
254 trace_rxrpc_transmit(call, (test_bit(RXRPC_CALL_TX_LAST, &call->flags) ?
255 rxrpc_transmit_rotate_last :
256 rxrpc_transmit_rotate));
257 wake_up(&call->waitq);
258
259 while (list) {
260 skb = list;
261 list = skb->next;
262 skb->next = NULL;
263 rxrpc_free_skb(skb, rxrpc_skb_tx_freed);
264 }
265 }
266
267 /*
268 * End the transmission phase of a call.
269 *
270 * This occurs when we get an ACKALL packet, the first DATA packet of a reply,
271 * or a final ACK packet.
272 */
273 static bool rxrpc_end_tx_phase(struct rxrpc_call *call, bool reply_begun,
274 const char *abort_why)
275 {
276
277 ASSERT(test_bit(RXRPC_CALL_TX_LAST, &call->flags));
278
279 write_lock(&call->state_lock);
280
281 switch (call->state) {
282 case RXRPC_CALL_CLIENT_SEND_REQUEST:
283 case RXRPC_CALL_CLIENT_AWAIT_REPLY:
284 if (reply_begun)
285 call->state = RXRPC_CALL_CLIENT_RECV_REPLY;
286 else
287 call->state = RXRPC_CALL_CLIENT_AWAIT_REPLY;
288 break;
289
290 case RXRPC_CALL_SERVER_AWAIT_ACK:
291 __rxrpc_call_completed(call);
292 rxrpc_notify_socket(call);
293 break;
294
295 default:
296 goto bad_state;
297 }
298
299 write_unlock(&call->state_lock);
300 if (call->state == RXRPC_CALL_CLIENT_AWAIT_REPLY) {
301 rxrpc_propose_ACK(call, RXRPC_ACK_IDLE, 0, 0, false, true,
302 rxrpc_propose_ack_client_tx_end);
303 trace_rxrpc_transmit(call, rxrpc_transmit_await_reply);
304 } else {
305 trace_rxrpc_transmit(call, rxrpc_transmit_end);
306 }
307 _leave(" = ok");
308 return true;
309
310 bad_state:
311 write_unlock(&call->state_lock);
312 kdebug("end_tx %s", rxrpc_call_states[call->state]);
313 rxrpc_proto_abort(abort_why, call, call->tx_top);
314 return false;
315 }
316
317 /*
318 * Begin the reply reception phase of a call.
319 */
320 static bool rxrpc_receiving_reply(struct rxrpc_call *call)
321 {
322 struct rxrpc_ack_summary summary = { 0 };
323 rxrpc_seq_t top = READ_ONCE(call->tx_top);
324
325 if (call->ackr_reason) {
326 spin_lock_bh(&call->lock);
327 call->ackr_reason = 0;
328 call->resend_at = call->expire_at;
329 call->ack_at = call->expire_at;
330 spin_unlock_bh(&call->lock);
331 rxrpc_set_timer(call, rxrpc_timer_init_for_reply,
332 ktime_get_real());
333 }
334
335 if (!test_bit(RXRPC_CALL_TX_LAST, &call->flags))
336 rxrpc_rotate_tx_window(call, top, &summary);
337 if (!test_bit(RXRPC_CALL_TX_LAST, &call->flags)) {
338 rxrpc_proto_abort("TXL", call, top);
339 return false;
340 }
341 if (!rxrpc_end_tx_phase(call, true, "ETD"))
342 return false;
343 call->tx_phase = false;
344 return true;
345 }
346
347 /*
348 * Scan a jumbo packet to validate its structure and to work out how many
349 * subpackets it contains.
350 *
351 * A jumbo packet is a collection of consecutive packets glued together with
352 * little headers between that indicate how to change the initial header for
353 * each subpacket.
354 *
355 * RXRPC_JUMBO_PACKET must be set on all but the last subpacket - and all but
356 * the last are RXRPC_JUMBO_DATALEN in size. The last subpacket may be of any
357 * size.
358 */
359 static bool rxrpc_validate_jumbo(struct sk_buff *skb)
360 {
361 struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
362 unsigned int offset = sizeof(struct rxrpc_wire_header);
363 unsigned int len = skb->len;
364 int nr_jumbo = 1;
365 u8 flags = sp->hdr.flags;
366
367 do {
368 nr_jumbo++;
369 if (len - offset < RXRPC_JUMBO_SUBPKTLEN)
370 goto protocol_error;
371 if (flags & RXRPC_LAST_PACKET)
372 goto protocol_error;
373 offset += RXRPC_JUMBO_DATALEN;
374 if (skb_copy_bits(skb, offset, &flags, 1) < 0)
375 goto protocol_error;
376 offset += sizeof(struct rxrpc_jumbo_header);
377 } while (flags & RXRPC_JUMBO_PACKET);
378
379 sp->nr_jumbo = nr_jumbo;
380 return true;
381
382 protocol_error:
383 return false;
384 }
385
386 /*
387 * Handle reception of a duplicate packet.
388 *
389 * We have to take care to avoid an attack here whereby we're given a series of
390 * jumbograms, each with a sequence number one before the preceding one and
391 * filled up to maximum UDP size. If they never send us the first packet in
392 * the sequence, they can cause us to have to hold on to around 2MiB of kernel
393 * space until the call times out.
394 *
395 * We limit the space usage by only accepting three duplicate jumbo packets per
396 * call. After that, we tell the other side we're no longer accepting jumbos
397 * (that information is encoded in the ACK packet).
398 */
399 static void rxrpc_input_dup_data(struct rxrpc_call *call, rxrpc_seq_t seq,
400 u8 annotation, bool *_jumbo_bad)
401 {
402 /* Discard normal packets that are duplicates. */
403 if (annotation == 0)
404 return;
405
406 /* Skip jumbo subpackets that are duplicates. When we've had three or
407 * more partially duplicate jumbo packets, we refuse to take any more
408 * jumbos for this call.
409 */
410 if (!*_jumbo_bad) {
411 call->nr_jumbo_bad++;
412 *_jumbo_bad = true;
413 }
414 }
415
416 /*
417 * Process a DATA packet, adding the packet to the Rx ring.
418 */
419 static void rxrpc_input_data(struct rxrpc_call *call, struct sk_buff *skb,
420 u16 skew)
421 {
422 struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
423 enum rxrpc_call_state state;
424 unsigned int offset = sizeof(struct rxrpc_wire_header);
425 unsigned int ix;
426 rxrpc_serial_t serial = sp->hdr.serial, ack_serial = 0;
427 rxrpc_seq_t seq = sp->hdr.seq, hard_ack;
428 bool immediate_ack = false, jumbo_bad = false, queued;
429 u16 len;
430 u8 ack = 0, flags, annotation = 0;
431
432 _enter("{%u,%u},{%u,%u}",
433 call->rx_hard_ack, call->rx_top, skb->len, seq);
434
435 _proto("Rx DATA %%%u { #%u f=%02x }",
436 sp->hdr.serial, seq, sp->hdr.flags);
437
438 state = READ_ONCE(call->state);
439 if (state >= RXRPC_CALL_COMPLETE)
440 return;
441
442 /* Received data implicitly ACKs all of the request packets we sent
443 * when we're acting as a client.
444 */
445 if ((state == RXRPC_CALL_CLIENT_SEND_REQUEST ||
446 state == RXRPC_CALL_CLIENT_AWAIT_REPLY) &&
447 !rxrpc_receiving_reply(call))
448 return;
449
450 call->ackr_prev_seq = seq;
451
452 hard_ack = READ_ONCE(call->rx_hard_ack);
453 if (after(seq, hard_ack + call->rx_winsize)) {
454 ack = RXRPC_ACK_EXCEEDS_WINDOW;
455 ack_serial = serial;
456 goto ack;
457 }
458
459 flags = sp->hdr.flags;
460 if (flags & RXRPC_JUMBO_PACKET) {
461 if (call->nr_jumbo_bad > 3) {
462 ack = RXRPC_ACK_NOSPACE;
463 ack_serial = serial;
464 goto ack;
465 }
466 annotation = 1;
467 }
468
469 next_subpacket:
470 queued = false;
471 ix = seq & RXRPC_RXTX_BUFF_MASK;
472 len = skb->len;
473 if (flags & RXRPC_JUMBO_PACKET)
474 len = RXRPC_JUMBO_DATALEN;
475
476 if (flags & RXRPC_LAST_PACKET) {
477 if (test_bit(RXRPC_CALL_RX_LAST, &call->flags) &&
478 seq != call->rx_top)
479 return rxrpc_proto_abort("LSN", call, seq);
480 } else {
481 if (test_bit(RXRPC_CALL_RX_LAST, &call->flags) &&
482 after_eq(seq, call->rx_top))
483 return rxrpc_proto_abort("LSA", call, seq);
484 }
485
486 trace_rxrpc_rx_data(call, seq, serial, flags, annotation);
487 if (before_eq(seq, hard_ack)) {
488 ack = RXRPC_ACK_DUPLICATE;
489 ack_serial = serial;
490 goto skip;
491 }
492
493 if (flags & RXRPC_REQUEST_ACK && !ack) {
494 ack = RXRPC_ACK_REQUESTED;
495 ack_serial = serial;
496 }
497
498 if (call->rxtx_buffer[ix]) {
499 rxrpc_input_dup_data(call, seq, annotation, &jumbo_bad);
500 if (ack != RXRPC_ACK_DUPLICATE) {
501 ack = RXRPC_ACK_DUPLICATE;
502 ack_serial = serial;
503 }
504 immediate_ack = true;
505 goto skip;
506 }
507
508 /* Queue the packet. We use a couple of memory barriers here as need
509 * to make sure that rx_top is perceived to be set after the buffer
510 * pointer and that the buffer pointer is set after the annotation and
511 * the skb data.
512 *
513 * Barriers against rxrpc_recvmsg_data() and rxrpc_rotate_rx_window()
514 * and also rxrpc_fill_out_ack().
515 */
516 rxrpc_get_skb(skb, rxrpc_skb_rx_got);
517 call->rxtx_annotations[ix] = annotation;
518 smp_wmb();
519 call->rxtx_buffer[ix] = skb;
520 if (after(seq, call->rx_top)) {
521 smp_store_release(&call->rx_top, seq);
522 } else if (before(seq, call->rx_top)) {
523 /* Send an immediate ACK if we fill in a hole */
524 if (!ack) {
525 ack = RXRPC_ACK_DELAY;
526 ack_serial = serial;
527 }
528 immediate_ack = true;
529 }
530 if (flags & RXRPC_LAST_PACKET) {
531 set_bit(RXRPC_CALL_RX_LAST, &call->flags);
532 trace_rxrpc_receive(call, rxrpc_receive_queue_last, serial, seq);
533 } else {
534 trace_rxrpc_receive(call, rxrpc_receive_queue, serial, seq);
535 }
536 queued = true;
537
538 if (after_eq(seq, call->rx_expect_next)) {
539 if (after(seq, call->rx_expect_next)) {
540 _net("OOS %u > %u", seq, call->rx_expect_next);
541 ack = RXRPC_ACK_OUT_OF_SEQUENCE;
542 ack_serial = serial;
543 }
544 call->rx_expect_next = seq + 1;
545 }
546
547 skip:
548 offset += len;
549 if (flags & RXRPC_JUMBO_PACKET) {
550 if (skb_copy_bits(skb, offset, &flags, 1) < 0)
551 return rxrpc_proto_abort("XJF", call, seq);
552 offset += sizeof(struct rxrpc_jumbo_header);
553 seq++;
554 serial++;
555 annotation++;
556 if (flags & RXRPC_JUMBO_PACKET)
557 annotation |= RXRPC_RX_ANNO_JLAST;
558 if (after(seq, hard_ack + call->rx_winsize)) {
559 ack = RXRPC_ACK_EXCEEDS_WINDOW;
560 ack_serial = serial;
561 if (!jumbo_bad) {
562 call->nr_jumbo_bad++;
563 jumbo_bad = true;
564 }
565 goto ack;
566 }
567
568 _proto("Rx DATA Jumbo %%%u", serial);
569 goto next_subpacket;
570 }
571
572 if (queued && flags & RXRPC_LAST_PACKET && !ack) {
573 ack = RXRPC_ACK_DELAY;
574 ack_serial = serial;
575 }
576
577 ack:
578 if (ack)
579 rxrpc_propose_ACK(call, ack, skew, ack_serial,
580 immediate_ack, true,
581 rxrpc_propose_ack_input_data);
582
583 if (sp->hdr.seq == READ_ONCE(call->rx_hard_ack) + 1)
584 rxrpc_notify_socket(call);
585 _leave(" [queued]");
586 }
587
588 /*
589 * Process a requested ACK.
590 */
591 static void rxrpc_input_requested_ack(struct rxrpc_call *call,
592 ktime_t resp_time,
593 rxrpc_serial_t orig_serial,
594 rxrpc_serial_t ack_serial)
595 {
596 struct rxrpc_skb_priv *sp;
597 struct sk_buff *skb;
598 ktime_t sent_at;
599 int ix;
600
601 for (ix = 0; ix < RXRPC_RXTX_BUFF_SIZE; ix++) {
602 skb = call->rxtx_buffer[ix];
603 if (!skb)
604 continue;
605
606 sp = rxrpc_skb(skb);
607 if (sp->hdr.serial != orig_serial)
608 continue;
609 smp_rmb();
610 sent_at = skb->tstamp;
611 goto found;
612 }
613 return;
614
615 found:
616 rxrpc_peer_add_rtt(call, rxrpc_rtt_rx_requested_ack,
617 orig_serial, ack_serial, sent_at, resp_time);
618 }
619
620 /*
621 * Process a ping response.
622 */
623 static void rxrpc_input_ping_response(struct rxrpc_call *call,
624 ktime_t resp_time,
625 rxrpc_serial_t orig_serial,
626 rxrpc_serial_t ack_serial)
627 {
628 rxrpc_serial_t ping_serial;
629 ktime_t ping_time;
630
631 ping_time = call->ping_time;
632 smp_rmb();
633 ping_serial = call->ping_serial;
634
635 if (!test_bit(RXRPC_CALL_PINGING, &call->flags) ||
636 before(orig_serial, ping_serial))
637 return;
638 clear_bit(RXRPC_CALL_PINGING, &call->flags);
639 if (after(orig_serial, ping_serial))
640 return;
641
642 rxrpc_peer_add_rtt(call, rxrpc_rtt_rx_ping_response,
643 orig_serial, ack_serial, ping_time, resp_time);
644 }
645
646 /*
647 * Process the extra information that may be appended to an ACK packet
648 */
649 static void rxrpc_input_ackinfo(struct rxrpc_call *call, struct sk_buff *skb,
650 struct rxrpc_ackinfo *ackinfo)
651 {
652 struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
653 struct rxrpc_peer *peer;
654 unsigned int mtu;
655 bool wake = false;
656 u32 rwind = ntohl(ackinfo->rwind);
657
658 _proto("Rx ACK %%%u Info { rx=%u max=%u rwin=%u jm=%u }",
659 sp->hdr.serial,
660 ntohl(ackinfo->rxMTU), ntohl(ackinfo->maxMTU),
661 rwind, ntohl(ackinfo->jumbo_max));
662
663 if (call->tx_winsize != rwind) {
664 if (rwind > RXRPC_RXTX_BUFF_SIZE - 1)
665 rwind = RXRPC_RXTX_BUFF_SIZE - 1;
666 if (rwind > call->tx_winsize)
667 wake = true;
668 trace_rxrpc_rx_rwind_change(call, sp->hdr.serial,
669 ntohl(ackinfo->rwind), wake);
670 call->tx_winsize = rwind;
671 }
672
673 if (call->cong_ssthresh > rwind)
674 call->cong_ssthresh = rwind;
675
676 mtu = min(ntohl(ackinfo->rxMTU), ntohl(ackinfo->maxMTU));
677
678 peer = call->peer;
679 if (mtu < peer->maxdata) {
680 spin_lock_bh(&peer->lock);
681 peer->maxdata = mtu;
682 peer->mtu = mtu + peer->hdrsize;
683 spin_unlock_bh(&peer->lock);
684 _net("Net MTU %u (maxdata %u)", peer->mtu, peer->maxdata);
685 }
686
687 if (wake)
688 wake_up(&call->waitq);
689 }
690
691 /*
692 * Process individual soft ACKs.
693 *
694 * Each ACK in the array corresponds to one packet and can be either an ACK or
695 * a NAK. If we get find an explicitly NAK'd packet we resend immediately;
696 * packets that lie beyond the end of the ACK list are scheduled for resend by
697 * the timer on the basis that the peer might just not have processed them at
698 * the time the ACK was sent.
699 */
700 static void rxrpc_input_soft_acks(struct rxrpc_call *call, u8 *acks,
701 rxrpc_seq_t seq, int nr_acks,
702 struct rxrpc_ack_summary *summary)
703 {
704 int ix;
705 u8 annotation, anno_type;
706
707 for (; nr_acks > 0; nr_acks--, seq++) {
708 ix = seq & RXRPC_RXTX_BUFF_MASK;
709 annotation = call->rxtx_annotations[ix];
710 anno_type = annotation & RXRPC_TX_ANNO_MASK;
711 annotation &= ~RXRPC_TX_ANNO_MASK;
712 switch (*acks++) {
713 case RXRPC_ACK_TYPE_ACK:
714 summary->nr_acks++;
715 if (anno_type == RXRPC_TX_ANNO_ACK)
716 continue;
717 summary->nr_new_acks++;
718 call->rxtx_annotations[ix] =
719 RXRPC_TX_ANNO_ACK | annotation;
720 break;
721 case RXRPC_ACK_TYPE_NACK:
722 if (!summary->nr_nacks &&
723 call->acks_lowest_nak != seq) {
724 call->acks_lowest_nak = seq;
725 summary->new_low_nack = true;
726 }
727 summary->nr_nacks++;
728 if (anno_type == RXRPC_TX_ANNO_NAK)
729 continue;
730 summary->nr_new_nacks++;
731 if (anno_type == RXRPC_TX_ANNO_RETRANS)
732 continue;
733 call->rxtx_annotations[ix] =
734 RXRPC_TX_ANNO_NAK | annotation;
735 break;
736 default:
737 return rxrpc_proto_abort("SFT", call, 0);
738 }
739 }
740 }
741
742 /*
743 * Process an ACK packet.
744 *
745 * ack.firstPacket is the sequence number of the first soft-ACK'd/NAK'd packet
746 * in the ACK array. Anything before that is hard-ACK'd and may be discarded.
747 *
748 * A hard-ACK means that a packet has been processed and may be discarded; a
749 * soft-ACK means that the packet may be discarded and retransmission
750 * requested. A phase is complete when all packets are hard-ACK'd.
751 */
752 static void rxrpc_input_ack(struct rxrpc_call *call, struct sk_buff *skb,
753 u16 skew)
754 {
755 struct rxrpc_ack_summary summary = { 0 };
756 struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
757 union {
758 struct rxrpc_ackpacket ack;
759 struct rxrpc_ackinfo info;
760 u8 acks[RXRPC_MAXACKS];
761 } buf;
762 rxrpc_serial_t acked_serial;
763 rxrpc_seq_t first_soft_ack, hard_ack;
764 int nr_acks, offset, ioffset;
765
766 _enter("");
767
768 offset = sizeof(struct rxrpc_wire_header);
769 if (skb_copy_bits(skb, offset, &buf.ack, sizeof(buf.ack)) < 0) {
770 _debug("extraction failure");
771 return rxrpc_proto_abort("XAK", call, 0);
772 }
773 offset += sizeof(buf.ack);
774
775 acked_serial = ntohl(buf.ack.serial);
776 first_soft_ack = ntohl(buf.ack.firstPacket);
777 hard_ack = first_soft_ack - 1;
778 nr_acks = buf.ack.nAcks;
779 summary.ack_reason = (buf.ack.reason < RXRPC_ACK__INVALID ?
780 buf.ack.reason : RXRPC_ACK__INVALID);
781
782 trace_rxrpc_rx_ack(call, sp->hdr.serial, acked_serial,
783 first_soft_ack, ntohl(buf.ack.previousPacket),
784 summary.ack_reason, nr_acks);
785
786 if (buf.ack.reason == RXRPC_ACK_PING_RESPONSE)
787 rxrpc_input_ping_response(call, skb->tstamp, acked_serial,
788 sp->hdr.serial);
789 if (buf.ack.reason == RXRPC_ACK_REQUESTED)
790 rxrpc_input_requested_ack(call, skb->tstamp, acked_serial,
791 sp->hdr.serial);
792
793 if (buf.ack.reason == RXRPC_ACK_PING) {
794 _proto("Rx ACK %%%u PING Request", sp->hdr.serial);
795 rxrpc_propose_ACK(call, RXRPC_ACK_PING_RESPONSE,
796 skew, sp->hdr.serial, true, true,
797 rxrpc_propose_ack_respond_to_ping);
798 } else if (sp->hdr.flags & RXRPC_REQUEST_ACK) {
799 rxrpc_propose_ACK(call, RXRPC_ACK_REQUESTED,
800 skew, sp->hdr.serial, true, true,
801 rxrpc_propose_ack_respond_to_ack);
802 }
803
804 ioffset = offset + nr_acks + 3;
805 if (skb->len >= ioffset + sizeof(buf.info)) {
806 if (skb_copy_bits(skb, ioffset, &buf.info, sizeof(buf.info)) < 0)
807 return rxrpc_proto_abort("XAI", call, 0);
808 rxrpc_input_ackinfo(call, skb, &buf.info);
809 }
810
811 if (first_soft_ack == 0)
812 return rxrpc_proto_abort("AK0", call, 0);
813
814 /* Ignore ACKs unless we are or have just been transmitting. */
815 switch (READ_ONCE(call->state)) {
816 case RXRPC_CALL_CLIENT_SEND_REQUEST:
817 case RXRPC_CALL_CLIENT_AWAIT_REPLY:
818 case RXRPC_CALL_SERVER_SEND_REPLY:
819 case RXRPC_CALL_SERVER_AWAIT_ACK:
820 break;
821 default:
822 return;
823 }
824
825 /* Discard any out-of-order or duplicate ACKs. */
826 if (before_eq(sp->hdr.serial, call->acks_latest)) {
827 _debug("discard ACK %d <= %d",
828 sp->hdr.serial, call->acks_latest);
829 return;
830 }
831 call->acks_latest_ts = skb->tstamp;
832 call->acks_latest = sp->hdr.serial;
833
834 if (before(hard_ack, call->tx_hard_ack) ||
835 after(hard_ack, call->tx_top))
836 return rxrpc_proto_abort("AKW", call, 0);
837 if (nr_acks > call->tx_top - hard_ack)
838 return rxrpc_proto_abort("AKN", call, 0);
839
840 if (after(hard_ack, call->tx_hard_ack))
841 rxrpc_rotate_tx_window(call, hard_ack, &summary);
842
843 if (nr_acks > 0) {
844 if (skb_copy_bits(skb, offset, buf.acks, nr_acks) < 0)
845 return rxrpc_proto_abort("XSA", call, 0);
846 rxrpc_input_soft_acks(call, buf.acks, first_soft_ack, nr_acks,
847 &summary);
848 }
849
850 if (test_bit(RXRPC_CALL_TX_LAST, &call->flags)) {
851 rxrpc_end_tx_phase(call, false, "ETA");
852 return;
853 }
854
855 if (call->rxtx_annotations[call->tx_top & RXRPC_RXTX_BUFF_MASK] &
856 RXRPC_TX_ANNO_LAST &&
857 summary.nr_acks == call->tx_top - hard_ack &&
858 rxrpc_is_client_call(call))
859 rxrpc_propose_ACK(call, RXRPC_ACK_PING, skew, sp->hdr.serial,
860 false, true,
861 rxrpc_propose_ack_ping_for_lost_reply);
862
863 return rxrpc_congestion_management(call, skb, &summary, acked_serial);
864 }
865
866 /*
867 * Process an ACKALL packet.
868 */
869 static void rxrpc_input_ackall(struct rxrpc_call *call, struct sk_buff *skb)
870 {
871 struct rxrpc_ack_summary summary = { 0 };
872 struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
873
874 _proto("Rx ACKALL %%%u", sp->hdr.serial);
875
876 rxrpc_rotate_tx_window(call, call->tx_top, &summary);
877 if (test_bit(RXRPC_CALL_TX_LAST, &call->flags))
878 rxrpc_end_tx_phase(call, false, "ETL");
879 }
880
881 /*
882 * Process an ABORT packet directed at a call.
883 */
884 static void rxrpc_input_abort(struct rxrpc_call *call, struct sk_buff *skb)
885 {
886 struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
887 __be32 wtmp;
888 u32 abort_code = RX_CALL_DEAD;
889
890 _enter("");
891
892 if (skb->len >= 4 &&
893 skb_copy_bits(skb, sizeof(struct rxrpc_wire_header),
894 &wtmp, sizeof(wtmp)) >= 0)
895 abort_code = ntohl(wtmp);
896
897 trace_rxrpc_rx_abort(call, sp->hdr.serial, abort_code);
898
899 _proto("Rx ABORT %%%u { %x }", sp->hdr.serial, abort_code);
900
901 if (rxrpc_set_call_completion(call, RXRPC_CALL_REMOTELY_ABORTED,
902 abort_code, -ECONNABORTED))
903 rxrpc_notify_socket(call);
904 }
905
906 /*
907 * Process an incoming call packet.
908 */
909 static void rxrpc_input_call_packet(struct rxrpc_call *call,
910 struct sk_buff *skb, u16 skew)
911 {
912 struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
913
914 _enter("%p,%p", call, skb);
915
916 switch (sp->hdr.type) {
917 case RXRPC_PACKET_TYPE_DATA:
918 rxrpc_input_data(call, skb, skew);
919 break;
920
921 case RXRPC_PACKET_TYPE_ACK:
922 rxrpc_input_ack(call, skb, skew);
923 break;
924
925 case RXRPC_PACKET_TYPE_BUSY:
926 _proto("Rx BUSY %%%u", sp->hdr.serial);
927
928 /* Just ignore BUSY packets from the server; the retry and
929 * lifespan timers will take care of business. BUSY packets
930 * from the client don't make sense.
931 */
932 break;
933
934 case RXRPC_PACKET_TYPE_ABORT:
935 rxrpc_input_abort(call, skb);
936 break;
937
938 case RXRPC_PACKET_TYPE_ACKALL:
939 rxrpc_input_ackall(call, skb);
940 break;
941
942 default:
943 break;
944 }
945
946 _leave("");
947 }
948
949 /*
950 * Handle a new call on a channel implicitly completing the preceding call on
951 * that channel.
952 *
953 * TODO: If callNumber > call_id + 1, renegotiate security.
954 */
955 static void rxrpc_input_implicit_end_call(struct rxrpc_connection *conn,
956 struct rxrpc_call *call)
957 {
958 switch (READ_ONCE(call->state)) {
959 case RXRPC_CALL_SERVER_AWAIT_ACK:
960 rxrpc_call_completed(call);
961 break;
962 case RXRPC_CALL_COMPLETE:
963 break;
964 default:
965 if (rxrpc_abort_call("IMP", call, 0, RX_CALL_DEAD, -ESHUTDOWN)) {
966 set_bit(RXRPC_CALL_EV_ABORT, &call->events);
967 rxrpc_queue_call(call);
968 }
969 break;
970 }
971
972 trace_rxrpc_improper_term(call);
973 __rxrpc_disconnect_call(conn, call);
974 rxrpc_notify_socket(call);
975 }
976
977 /*
978 * post connection-level events to the connection
979 * - this includes challenges, responses, some aborts and call terminal packet
980 * retransmission.
981 */
982 static void rxrpc_post_packet_to_conn(struct rxrpc_connection *conn,
983 struct sk_buff *skb)
984 {
985 _enter("%p,%p", conn, skb);
986
987 skb_queue_tail(&conn->rx_queue, skb);
988 rxrpc_queue_conn(conn);
989 }
990
991 /*
992 * post endpoint-level events to the local endpoint
993 * - this includes debug and version messages
994 */
995 static void rxrpc_post_packet_to_local(struct rxrpc_local *local,
996 struct sk_buff *skb)
997 {
998 _enter("%p,%p", local, skb);
999
1000 skb_queue_tail(&local->event_queue, skb);
1001 rxrpc_queue_local(local);
1002 }
1003
1004 /*
1005 * put a packet up for transport-level abort
1006 */
1007 static void rxrpc_reject_packet(struct rxrpc_local *local, struct sk_buff *skb)
1008 {
1009 CHECK_SLAB_OKAY(&local->usage);
1010
1011 skb_queue_tail(&local->reject_queue, skb);
1012 rxrpc_queue_local(local);
1013 }
1014
1015 /*
1016 * Extract the wire header from a packet and translate the byte order.
1017 */
1018 static noinline
1019 int rxrpc_extract_header(struct rxrpc_skb_priv *sp, struct sk_buff *skb)
1020 {
1021 struct rxrpc_wire_header whdr;
1022
1023 /* dig out the RxRPC connection details */
1024 if (skb_copy_bits(skb, 0, &whdr, sizeof(whdr)) < 0) {
1025 trace_rxrpc_rx_eproto(NULL, sp->hdr.serial,
1026 tracepoint_string("bad_hdr"));
1027 return -EBADMSG;
1028 }
1029
1030 memset(sp, 0, sizeof(*sp));
1031 sp->hdr.epoch = ntohl(whdr.epoch);
1032 sp->hdr.cid = ntohl(whdr.cid);
1033 sp->hdr.callNumber = ntohl(whdr.callNumber);
1034 sp->hdr.seq = ntohl(whdr.seq);
1035 sp->hdr.serial = ntohl(whdr.serial);
1036 sp->hdr.flags = whdr.flags;
1037 sp->hdr.type = whdr.type;
1038 sp->hdr.userStatus = whdr.userStatus;
1039 sp->hdr.securityIndex = whdr.securityIndex;
1040 sp->hdr._rsvd = ntohs(whdr._rsvd);
1041 sp->hdr.serviceId = ntohs(whdr.serviceId);
1042 return 0;
1043 }
1044
1045 /*
1046 * handle data received on the local endpoint
1047 * - may be called in interrupt context
1048 *
1049 * The socket is locked by the caller and this prevents the socket from being
1050 * shut down and the local endpoint from going away, thus sk_user_data will not
1051 * be cleared until this function returns.
1052 */
1053 void rxrpc_data_ready(struct sock *udp_sk)
1054 {
1055 struct rxrpc_connection *conn;
1056 struct rxrpc_channel *chan;
1057 struct rxrpc_call *call;
1058 struct rxrpc_skb_priv *sp;
1059 struct rxrpc_local *local = udp_sk->sk_user_data;
1060 struct sk_buff *skb;
1061 unsigned int channel;
1062 int ret, skew;
1063
1064 _enter("%p", udp_sk);
1065
1066 ASSERT(!irqs_disabled());
1067
1068 skb = skb_recv_udp(udp_sk, 0, 1, &ret);
1069 if (!skb) {
1070 if (ret == -EAGAIN)
1071 return;
1072 _debug("UDP socket error %d", ret);
1073 return;
1074 }
1075
1076 rxrpc_new_skb(skb, rxrpc_skb_rx_received);
1077
1078 _net("recv skb %p", skb);
1079
1080 /* we'll probably need to checksum it (didn't call sock_recvmsg) */
1081 if (skb_checksum_complete(skb)) {
1082 rxrpc_free_skb(skb, rxrpc_skb_rx_freed);
1083 __UDP_INC_STATS(&init_net, UDP_MIB_INERRORS, 0);
1084 _leave(" [CSUM failed]");
1085 return;
1086 }
1087
1088 __UDP_INC_STATS(&init_net, UDP_MIB_INDATAGRAMS, 0);
1089
1090 /* The UDP protocol already released all skb resources;
1091 * we are free to add our own data there.
1092 */
1093 sp = rxrpc_skb(skb);
1094
1095 /* dig out the RxRPC connection details */
1096 if (rxrpc_extract_header(sp, skb) < 0)
1097 goto bad_message;
1098
1099 if (IS_ENABLED(CONFIG_AF_RXRPC_INJECT_LOSS)) {
1100 static int lose;
1101 if ((lose++ & 7) == 7) {
1102 trace_rxrpc_rx_lose(sp);
1103 rxrpc_lose_skb(skb, rxrpc_skb_rx_lost);
1104 return;
1105 }
1106 }
1107
1108 trace_rxrpc_rx_packet(sp);
1109
1110 _net("Rx RxRPC %s ep=%x call=%x:%x",
1111 sp->hdr.flags & RXRPC_CLIENT_INITIATED ? "ToServer" : "ToClient",
1112 sp->hdr.epoch, sp->hdr.cid, sp->hdr.callNumber);
1113
1114 if (sp->hdr.type >= RXRPC_N_PACKET_TYPES ||
1115 !((RXRPC_SUPPORTED_PACKET_TYPES >> sp->hdr.type) & 1)) {
1116 _proto("Rx Bad Packet Type %u", sp->hdr.type);
1117 goto bad_message;
1118 }
1119
1120 switch (sp->hdr.type) {
1121 case RXRPC_PACKET_TYPE_VERSION:
1122 rxrpc_post_packet_to_local(local, skb);
1123 goto out;
1124
1125 case RXRPC_PACKET_TYPE_BUSY:
1126 if (sp->hdr.flags & RXRPC_CLIENT_INITIATED)
1127 goto discard;
1128
1129 case RXRPC_PACKET_TYPE_DATA:
1130 if (sp->hdr.callNumber == 0)
1131 goto bad_message;
1132 if (sp->hdr.flags & RXRPC_JUMBO_PACKET &&
1133 !rxrpc_validate_jumbo(skb))
1134 goto bad_message;
1135 break;
1136 }
1137
1138 rcu_read_lock();
1139
1140 conn = rxrpc_find_connection_rcu(local, skb);
1141 if (conn) {
1142 if (sp->hdr.securityIndex != conn->security_ix)
1143 goto wrong_security;
1144
1145 if (sp->hdr.serviceId != conn->service_id) {
1146 if (!test_bit(RXRPC_CONN_PROBING_FOR_UPGRADE, &conn->flags) ||
1147 conn->service_id != conn->params.service_id)
1148 goto reupgrade;
1149 conn->service_id = sp->hdr.serviceId;
1150 }
1151
1152 if (sp->hdr.callNumber == 0) {
1153 /* Connection-level packet */
1154 _debug("CONN %p {%d}", conn, conn->debug_id);
1155 rxrpc_post_packet_to_conn(conn, skb);
1156 goto out_unlock;
1157 }
1158
1159 /* Note the serial number skew here */
1160 skew = (int)sp->hdr.serial - (int)conn->hi_serial;
1161 if (skew >= 0) {
1162 if (skew > 0)
1163 conn->hi_serial = sp->hdr.serial;
1164 } else {
1165 skew = -skew;
1166 skew = min(skew, 65535);
1167 }
1168
1169 /* Call-bound packets are routed by connection channel. */
1170 channel = sp->hdr.cid & RXRPC_CHANNELMASK;
1171 chan = &conn->channels[channel];
1172
1173 /* Ignore really old calls */
1174 if (sp->hdr.callNumber < chan->last_call)
1175 goto discard_unlock;
1176
1177 if (sp->hdr.callNumber == chan->last_call) {
1178 /* For the previous service call, if completed successfully, we
1179 * discard all further packets.
1180 */
1181 if (rxrpc_conn_is_service(conn) &&
1182 (chan->last_type == RXRPC_PACKET_TYPE_ACK ||
1183 sp->hdr.type == RXRPC_PACKET_TYPE_ABORT))
1184 goto discard_unlock;
1185
1186 /* But otherwise we need to retransmit the final packet from
1187 * data cached in the connection record.
1188 */
1189 rxrpc_post_packet_to_conn(conn, skb);
1190 goto out_unlock;
1191 }
1192
1193 call = rcu_dereference(chan->call);
1194
1195 if (sp->hdr.callNumber > chan->call_id) {
1196 if (!(sp->hdr.flags & RXRPC_CLIENT_INITIATED)) {
1197 rcu_read_unlock();
1198 goto reject_packet;
1199 }
1200 if (call)
1201 rxrpc_input_implicit_end_call(conn, call);
1202 call = NULL;
1203 }
1204
1205 if (call && sp->hdr.serviceId != call->service_id)
1206 call->service_id = sp->hdr.serviceId;
1207 } else {
1208 skew = 0;
1209 call = NULL;
1210 }
1211
1212 if (!call || atomic_read(&call->usage) == 0) {
1213 if (!(sp->hdr.type & RXRPC_CLIENT_INITIATED) ||
1214 sp->hdr.callNumber == 0 ||
1215 sp->hdr.type != RXRPC_PACKET_TYPE_DATA)
1216 goto bad_message_unlock;
1217 if (sp->hdr.seq != 1)
1218 goto discard_unlock;
1219 call = rxrpc_new_incoming_call(local, conn, skb);
1220 if (!call) {
1221 rcu_read_unlock();
1222 goto reject_packet;
1223 }
1224 rxrpc_send_ping(call, skb, skew);
1225 mutex_unlock(&call->user_mutex);
1226 }
1227
1228 rxrpc_input_call_packet(call, skb, skew);
1229 goto discard_unlock;
1230
1231 discard_unlock:
1232 rcu_read_unlock();
1233 discard:
1234 rxrpc_free_skb(skb, rxrpc_skb_rx_freed);
1235 out:
1236 trace_rxrpc_rx_done(0, 0);
1237 return;
1238
1239 out_unlock:
1240 rcu_read_unlock();
1241 goto out;
1242
1243 wrong_security:
1244 rcu_read_unlock();
1245 trace_rxrpc_abort("SEC", sp->hdr.cid, sp->hdr.callNumber, sp->hdr.seq,
1246 RXKADINCONSISTENCY, EBADMSG);
1247 skb->priority = RXKADINCONSISTENCY;
1248 goto post_abort;
1249
1250 reupgrade:
1251 rcu_read_unlock();
1252 trace_rxrpc_abort("UPG", sp->hdr.cid, sp->hdr.callNumber, sp->hdr.seq,
1253 RX_PROTOCOL_ERROR, EBADMSG);
1254 goto protocol_error;
1255
1256 bad_message_unlock:
1257 rcu_read_unlock();
1258 bad_message:
1259 trace_rxrpc_abort("BAD", sp->hdr.cid, sp->hdr.callNumber, sp->hdr.seq,
1260 RX_PROTOCOL_ERROR, EBADMSG);
1261 protocol_error:
1262 skb->priority = RX_PROTOCOL_ERROR;
1263 post_abort:
1264 skb->mark = RXRPC_SKB_MARK_LOCAL_ABORT;
1265 reject_packet:
1266 trace_rxrpc_rx_done(skb->mark, skb->priority);
1267 rxrpc_reject_packet(local, skb);
1268 _leave(" [badmsg]");
1269 }
(deprecated) Btrfs devel tree