1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /* RxRPC packet reception
3 *
4 * Copyright (C) 2007, 2016 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/net.h>
12 #include <linux/skbuff.h>
13 #include <linux/errqueue.h>
14 #include <linux/udp.h>
15 #include <linux/in.h>
16 #include <linux/in6.h>
17 #include <linux/icmp.h>
18 #include <linux/gfp.h>
19 #include <net/sock.h>
20 #include <net/af_rxrpc.h>
21 #include <net/ip.h>
22 #include <net/udp.h>
23 #include <net/net_namespace.h>
24 #include "ar-internal.h"
25
rxrpc_proto_abort(const char * why,struct rxrpc_call * call,rxrpc_seq_t seq)26 static void rxrpc_proto_abort(const char *why,
27 struct rxrpc_call *call, rxrpc_seq_t seq)
28 {
29 if (rxrpc_abort_call(why, call, seq, RX_PROTOCOL_ERROR, -EBADMSG)) {
30 set_bit(RXRPC_CALL_EV_ABORT, &call->events);
31 rxrpc_queue_call(call);
32 }
33 }
34
35 /*
36 * Do TCP-style congestion management [RFC 5681].
37 */
rxrpc_congestion_management(struct rxrpc_call * call,struct sk_buff * skb,struct rxrpc_ack_summary * summary,rxrpc_serial_t acked_serial)38 static void rxrpc_congestion_management(struct rxrpc_call *call,
39 struct sk_buff *skb,
40 struct rxrpc_ack_summary *summary,
41 rxrpc_serial_t acked_serial)
42 {
43 enum rxrpc_congest_change change = rxrpc_cong_no_change;
44 unsigned int cumulative_acks = call->cong_cumul_acks;
45 unsigned int cwnd = call->cong_cwnd;
46 bool resend = false;
47
48 summary->flight_size =
49 (call->tx_top - call->tx_hard_ack) - summary->nr_acks;
50
51 if (test_and_clear_bit(RXRPC_CALL_RETRANS_TIMEOUT, &call->flags)) {
52 summary->retrans_timeo = true;
53 call->cong_ssthresh = max_t(unsigned int,
54 summary->flight_size / 2, 2);
55 cwnd = 1;
56 if (cwnd >= call->cong_ssthresh &&
57 call->cong_mode == RXRPC_CALL_SLOW_START) {
58 call->cong_mode = RXRPC_CALL_CONGEST_AVOIDANCE;
59 call->cong_tstamp = skb->tstamp;
60 cumulative_acks = 0;
61 }
62 }
63
64 cumulative_acks += summary->nr_new_acks;
65 cumulative_acks += summary->nr_rot_new_acks;
66 if (cumulative_acks > 255)
67 cumulative_acks = 255;
68
69 summary->mode = call->cong_mode;
70 summary->cwnd = call->cong_cwnd;
71 summary->ssthresh = call->cong_ssthresh;
72 summary->cumulative_acks = cumulative_acks;
73 summary->dup_acks = call->cong_dup_acks;
74
75 switch (call->cong_mode) {
76 case RXRPC_CALL_SLOW_START:
77 if (summary->nr_nacks > 0)
78 goto packet_loss_detected;
79 if (summary->cumulative_acks > 0)
80 cwnd += 1;
81 if (cwnd >= call->cong_ssthresh) {
82 call->cong_mode = RXRPC_CALL_CONGEST_AVOIDANCE;
83 call->cong_tstamp = skb->tstamp;
84 }
85 goto out;
86
87 case RXRPC_CALL_CONGEST_AVOIDANCE:
88 if (summary->nr_nacks > 0)
89 goto packet_loss_detected;
90
91 /* We analyse the number of packets that get ACK'd per RTT
92 * period and increase the window if we managed to fill it.
93 */
94 if (call->peer->rtt_count == 0)
95 goto out;
96 if (ktime_before(skb->tstamp,
97 ktime_add_us(call->cong_tstamp,
98 call->peer->srtt_us >> 3)))
99 goto out_no_clear_ca;
100 change = rxrpc_cong_rtt_window_end;
101 call->cong_tstamp = skb->tstamp;
102 if (cumulative_acks >= cwnd)
103 cwnd++;
104 goto out;
105
106 case RXRPC_CALL_PACKET_LOSS:
107 if (summary->nr_nacks == 0)
108 goto resume_normality;
109
110 if (summary->new_low_nack) {
111 change = rxrpc_cong_new_low_nack;
112 call->cong_dup_acks = 1;
113 if (call->cong_extra > 1)
114 call->cong_extra = 1;
115 goto send_extra_data;
116 }
117
118 call->cong_dup_acks++;
119 if (call->cong_dup_acks < 3)
120 goto send_extra_data;
121
122 change = rxrpc_cong_begin_retransmission;
123 call->cong_mode = RXRPC_CALL_FAST_RETRANSMIT;
124 call->cong_ssthresh = max_t(unsigned int,
125 summary->flight_size / 2, 2);
126 cwnd = call->cong_ssthresh + 3;
127 call->cong_extra = 0;
128 call->cong_dup_acks = 0;
129 resend = true;
130 goto out;
131
132 case RXRPC_CALL_FAST_RETRANSMIT:
133 if (!summary->new_low_nack) {
134 if (summary->nr_new_acks == 0)
135 cwnd += 1;
136 call->cong_dup_acks++;
137 if (call->cong_dup_acks == 2) {
138 change = rxrpc_cong_retransmit_again;
139 call->cong_dup_acks = 0;
140 resend = true;
141 }
142 } else {
143 change = rxrpc_cong_progress;
144 cwnd = call->cong_ssthresh;
145 if (summary->nr_nacks == 0)
146 goto resume_normality;
147 }
148 goto out;
149
150 default:
151 BUG();
152 goto out;
153 }
154
155 resume_normality:
156 change = rxrpc_cong_cleared_nacks;
157 call->cong_dup_acks = 0;
158 call->cong_extra = 0;
159 call->cong_tstamp = skb->tstamp;
160 if (cwnd < call->cong_ssthresh)
161 call->cong_mode = RXRPC_CALL_SLOW_START;
162 else
163 call->cong_mode = RXRPC_CALL_CONGEST_AVOIDANCE;
164 out:
165 cumulative_acks = 0;
166 out_no_clear_ca:
167 if (cwnd >= RXRPC_RXTX_BUFF_SIZE - 1)
168 cwnd = RXRPC_RXTX_BUFF_SIZE - 1;
169 call->cong_cwnd = cwnd;
170 call->cong_cumul_acks = cumulative_acks;
171 trace_rxrpc_congest(call, summary, acked_serial, change);
172 if (resend && !test_and_set_bit(RXRPC_CALL_EV_RESEND, &call->events))
173 rxrpc_queue_call(call);
174 return;
175
176 packet_loss_detected:
177 change = rxrpc_cong_saw_nack;
178 call->cong_mode = RXRPC_CALL_PACKET_LOSS;
179 call->cong_dup_acks = 0;
180 goto send_extra_data;
181
182 send_extra_data:
183 /* Send some previously unsent DATA if we have some to advance the ACK
184 * state.
185 */
186 if (call->rxtx_annotations[call->tx_top & RXRPC_RXTX_BUFF_MASK] &
187 RXRPC_TX_ANNO_LAST ||
188 summary->nr_acks != call->tx_top - call->tx_hard_ack) {
189 call->cong_extra++;
190 wake_up(&call->waitq);
191 }
192 goto out_no_clear_ca;
193 }
194
195 /*
196 * Apply a hard ACK by advancing the Tx window.
197 */
rxrpc_rotate_tx_window(struct rxrpc_call * call,rxrpc_seq_t to,struct rxrpc_ack_summary * summary)198 static bool rxrpc_rotate_tx_window(struct rxrpc_call *call, rxrpc_seq_t to,
199 struct rxrpc_ack_summary *summary)
200 {
201 struct sk_buff *skb, *list = NULL;
202 bool rot_last = false;
203 int ix;
204 u8 annotation;
205
206 if (call->acks_lowest_nak == call->tx_hard_ack) {
207 call->acks_lowest_nak = to;
208 } else if (before_eq(call->acks_lowest_nak, to)) {
209 summary->new_low_nack = true;
210 call->acks_lowest_nak = to;
211 }
212
213 spin_lock(&call->lock);
214
215 while (before(call->tx_hard_ack, to)) {
216 call->tx_hard_ack++;
217 ix = call->tx_hard_ack & RXRPC_RXTX_BUFF_MASK;
218 skb = call->rxtx_buffer[ix];
219 annotation = call->rxtx_annotations[ix];
220 rxrpc_see_skb(skb, rxrpc_skb_rotated);
221 call->rxtx_buffer[ix] = NULL;
222 call->rxtx_annotations[ix] = 0;
223 skb->next = list;
224 list = skb;
225
226 if (annotation & RXRPC_TX_ANNO_LAST) {
227 set_bit(RXRPC_CALL_TX_LAST, &call->flags);
228 rot_last = true;
229 }
230 if ((annotation & RXRPC_TX_ANNO_MASK) != RXRPC_TX_ANNO_ACK)
231 summary->nr_rot_new_acks++;
232 }
233
234 spin_unlock(&call->lock);
235
236 trace_rxrpc_transmit(call, (rot_last ?
237 rxrpc_transmit_rotate_last :
238 rxrpc_transmit_rotate));
239 wake_up(&call->waitq);
240
241 while (list) {
242 skb = list;
243 list = skb->next;
244 skb_mark_not_on_list(skb);
245 rxrpc_free_skb(skb, rxrpc_skb_freed);
246 }
247
248 return rot_last;
249 }
250
251 /*
252 * End the transmission phase of a call.
253 *
254 * This occurs when we get an ACKALL packet, the first DATA packet of a reply,
255 * or a final ACK packet.
256 */
rxrpc_end_tx_phase(struct rxrpc_call * call,bool reply_begun,const char * abort_why)257 static bool rxrpc_end_tx_phase(struct rxrpc_call *call, bool reply_begun,
258 const char *abort_why)
259 {
260 unsigned int state;
261
262 ASSERT(test_bit(RXRPC_CALL_TX_LAST, &call->flags));
263
264 write_lock(&call->state_lock);
265
266 state = call->state;
267 switch (state) {
268 case RXRPC_CALL_CLIENT_SEND_REQUEST:
269 case RXRPC_CALL_CLIENT_AWAIT_REPLY:
270 if (reply_begun)
271 call->state = state = RXRPC_CALL_CLIENT_RECV_REPLY;
272 else
273 call->state = state = RXRPC_CALL_CLIENT_AWAIT_REPLY;
274 break;
275
276 case RXRPC_CALL_SERVER_AWAIT_ACK:
277 __rxrpc_call_completed(call);
278 state = call->state;
279 break;
280
281 default:
282 goto bad_state;
283 }
284
285 write_unlock(&call->state_lock);
286 if (state == RXRPC_CALL_CLIENT_AWAIT_REPLY)
287 trace_rxrpc_transmit(call, rxrpc_transmit_await_reply);
288 else
289 trace_rxrpc_transmit(call, rxrpc_transmit_end);
290 _leave(" = ok");
291 return true;
292
293 bad_state:
294 write_unlock(&call->state_lock);
295 kdebug("end_tx %s", rxrpc_call_states[call->state]);
296 rxrpc_proto_abort(abort_why, call, call->tx_top);
297 return false;
298 }
299
300 /*
301 * Begin the reply reception phase of a call.
302 */
rxrpc_receiving_reply(struct rxrpc_call * call)303 static bool rxrpc_receiving_reply(struct rxrpc_call *call)
304 {
305 struct rxrpc_ack_summary summary = { 0 };
306 unsigned long now, timo;
307 rxrpc_seq_t top = READ_ONCE(call->tx_top);
308
309 if (call->ackr_reason) {
310 spin_lock_bh(&call->lock);
311 call->ackr_reason = 0;
312 spin_unlock_bh(&call->lock);
313 now = jiffies;
314 timo = now + MAX_JIFFY_OFFSET;
315 WRITE_ONCE(call->resend_at, timo);
316 WRITE_ONCE(call->ack_at, timo);
317 trace_rxrpc_timer(call, rxrpc_timer_init_for_reply, now);
318 }
319
320 if (!test_bit(RXRPC_CALL_TX_LAST, &call->flags)) {
321 if (!rxrpc_rotate_tx_window(call, top, &summary)) {
322 rxrpc_proto_abort("TXL", call, top);
323 return false;
324 }
325 }
326 if (!rxrpc_end_tx_phase(call, true, "ETD"))
327 return false;
328 call->tx_phase = false;
329 return true;
330 }
331
332 /*
333 * Scan a data packet to validate its structure and to work out how many
334 * subpackets it contains.
335 *
336 * A jumbo packet is a collection of consecutive packets glued together with
337 * little headers between that indicate how to change the initial header for
338 * each subpacket.
339 *
340 * RXRPC_JUMBO_PACKET must be set on all but the last subpacket - and all but
341 * the last are RXRPC_JUMBO_DATALEN in size. The last subpacket may be of any
342 * size.
343 */
rxrpc_validate_data(struct sk_buff * skb)344 static bool rxrpc_validate_data(struct sk_buff *skb)
345 {
346 struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
347 unsigned int offset = sizeof(struct rxrpc_wire_header);
348 unsigned int len = skb->len;
349 u8 flags = sp->hdr.flags;
350
351 for (;;) {
352 if (flags & RXRPC_REQUEST_ACK)
353 __set_bit(sp->nr_subpackets, sp->rx_req_ack);
354 sp->nr_subpackets++;
355
356 if (!(flags & RXRPC_JUMBO_PACKET))
357 break;
358
359 if (len - offset < RXRPC_JUMBO_SUBPKTLEN)
360 goto protocol_error;
361 if (flags & RXRPC_LAST_PACKET)
362 goto protocol_error;
363 offset += RXRPC_JUMBO_DATALEN;
364 if (skb_copy_bits(skb, offset, &flags, 1) < 0)
365 goto protocol_error;
366 offset += sizeof(struct rxrpc_jumbo_header);
367 }
368
369 if (flags & RXRPC_LAST_PACKET)
370 sp->rx_flags |= RXRPC_SKB_INCL_LAST;
371 return true;
372
373 protocol_error:
374 return false;
375 }
376
377 /*
378 * Handle reception of a duplicate packet.
379 *
380 * We have to take care to avoid an attack here whereby we're given a series of
381 * jumbograms, each with a sequence number one before the preceding one and
382 * filled up to maximum UDP size. If they never send us the first packet in
383 * the sequence, they can cause us to have to hold on to around 2MiB of kernel
384 * space until the call times out.
385 *
386 * We limit the space usage by only accepting three duplicate jumbo packets per
387 * call. After that, we tell the other side we're no longer accepting jumbos
388 * (that information is encoded in the ACK packet).
389 */
rxrpc_input_dup_data(struct rxrpc_call * call,rxrpc_seq_t seq,bool is_jumbo,bool * _jumbo_bad)390 static void rxrpc_input_dup_data(struct rxrpc_call *call, rxrpc_seq_t seq,
391 bool is_jumbo, bool *_jumbo_bad)
392 {
393 /* Discard normal packets that are duplicates. */
394 if (is_jumbo)
395 return;
396
397 /* Skip jumbo subpackets that are duplicates. When we've had three or
398 * more partially duplicate jumbo packets, we refuse to take any more
399 * jumbos for this call.
400 */
401 if (!*_jumbo_bad) {
402 call->nr_jumbo_bad++;
403 *_jumbo_bad = true;
404 }
405 }
406
407 /*
408 * Process a DATA packet, adding the packet to the Rx ring. The caller's
409 * packet ref must be passed on or discarded.
410 */
rxrpc_input_data(struct rxrpc_call * call,struct sk_buff * skb)411 static void rxrpc_input_data(struct rxrpc_call *call, struct sk_buff *skb)
412 {
413 struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
414 enum rxrpc_call_state state;
415 unsigned int j, nr_subpackets, nr_unacked = 0;
416 rxrpc_serial_t serial = sp->hdr.serial, ack_serial = serial;
417 rxrpc_seq_t seq0 = sp->hdr.seq, hard_ack;
418 bool immediate_ack = false, jumbo_bad = false;
419 u8 ack = 0;
420
421 _enter("{%u,%u},{%u,%u}",
422 call->rx_hard_ack, call->rx_top, skb->len, seq0);
423
424 _proto("Rx DATA %%%u { #%u f=%02x n=%u }",
425 sp->hdr.serial, seq0, sp->hdr.flags, sp->nr_subpackets);
426
427 state = READ_ONCE(call->state);
428 if (state >= RXRPC_CALL_COMPLETE) {
429 rxrpc_free_skb(skb, rxrpc_skb_freed);
430 return;
431 }
432
433 if (state == RXRPC_CALL_SERVER_RECV_REQUEST) {
434 unsigned long timo = READ_ONCE(call->next_req_timo);
435 unsigned long now, expect_req_by;
436
437 if (timo) {
438 now = jiffies;
439 expect_req_by = now + timo;
440 WRITE_ONCE(call->expect_req_by, expect_req_by);
441 rxrpc_reduce_call_timer(call, expect_req_by, now,
442 rxrpc_timer_set_for_idle);
443 }
444 }
445
446 spin_lock(&call->input_lock);
447
448 /* Received data implicitly ACKs all of the request packets we sent
449 * when we're acting as a client.
450 */
451 if ((state == RXRPC_CALL_CLIENT_SEND_REQUEST ||
452 state == RXRPC_CALL_CLIENT_AWAIT_REPLY) &&
453 !rxrpc_receiving_reply(call))
454 goto unlock;
455
456 hard_ack = READ_ONCE(call->rx_hard_ack);
457
458 nr_subpackets = sp->nr_subpackets;
459 if (nr_subpackets > 1) {
460 if (call->nr_jumbo_bad > 3) {
461 ack = RXRPC_ACK_NOSPACE;
462 ack_serial = serial;
463 goto ack;
464 }
465 }
466
467 for (j = 0; j < nr_subpackets; j++) {
468 rxrpc_serial_t serial = sp->hdr.serial + j;
469 rxrpc_seq_t seq = seq0 + j;
470 unsigned int ix = seq & RXRPC_RXTX_BUFF_MASK;
471 bool terminal = (j == nr_subpackets - 1);
472 bool last = terminal && (sp->rx_flags & RXRPC_SKB_INCL_LAST);
473 u8 flags, annotation = j;
474
475 _proto("Rx DATA+%u %%%u { #%x t=%u l=%u }",
476 j, serial, seq, terminal, last);
477
478 if (last) {
479 if (test_bit(RXRPC_CALL_RX_LAST, &call->flags) &&
480 seq != call->rx_top) {
481 rxrpc_proto_abort("LSN", call, seq);
482 goto unlock;
483 }
484 } else {
485 if (test_bit(RXRPC_CALL_RX_LAST, &call->flags) &&
486 after_eq(seq, call->rx_top)) {
487 rxrpc_proto_abort("LSA", call, seq);
488 goto unlock;
489 }
490 }
491
492 flags = 0;
493 if (last)
494 flags |= RXRPC_LAST_PACKET;
495 if (!terminal)
496 flags |= RXRPC_JUMBO_PACKET;
497 if (test_bit(j, sp->rx_req_ack))
498 flags |= RXRPC_REQUEST_ACK;
499 trace_rxrpc_rx_data(call->debug_id, seq, serial, flags, annotation);
500
501 if (before_eq(seq, hard_ack)) {
502 ack = RXRPC_ACK_DUPLICATE;
503 ack_serial = serial;
504 continue;
505 }
506
507 if (call->rxtx_buffer[ix]) {
508 rxrpc_input_dup_data(call, seq, nr_subpackets > 1,
509 &jumbo_bad);
510 if (ack != RXRPC_ACK_DUPLICATE) {
511 ack = RXRPC_ACK_DUPLICATE;
512 ack_serial = serial;
513 }
514 immediate_ack = true;
515 continue;
516 }
517
518 if (after(seq, hard_ack + call->rx_winsize)) {
519 ack = RXRPC_ACK_EXCEEDS_WINDOW;
520 ack_serial = serial;
521 if (flags & RXRPC_JUMBO_PACKET) {
522 if (!jumbo_bad) {
523 call->nr_jumbo_bad++;
524 jumbo_bad = true;
525 }
526 }
527
528 goto ack;
529 }
530
531 if (flags & RXRPC_REQUEST_ACK && !ack) {
532 ack = RXRPC_ACK_REQUESTED;
533 ack_serial = serial;
534 }
535
536 if (after(seq0, call->ackr_highest_seq))
537 call->ackr_highest_seq = seq0;
538
539 /* Queue the packet. We use a couple of memory barriers here as need
540 * to make sure that rx_top is perceived to be set after the buffer
541 * pointer and that the buffer pointer is set after the annotation and
542 * the skb data.
543 *
544 * Barriers against rxrpc_recvmsg_data() and rxrpc_rotate_rx_window()
545 * and also rxrpc_fill_out_ack().
546 */
547 if (!terminal)
548 rxrpc_get_skb(skb, rxrpc_skb_got);
549 call->rxtx_annotations[ix] = annotation;
550 smp_wmb();
551 call->rxtx_buffer[ix] = skb;
552 if (after(seq, call->rx_top)) {
553 smp_store_release(&call->rx_top, seq);
554 } else if (before(seq, call->rx_top)) {
555 /* Send an immediate ACK if we fill in a hole */
556 if (!ack) {
557 ack = RXRPC_ACK_DELAY;
558 ack_serial = serial;
559 }
560 immediate_ack = true;
561 }
562
563 if (terminal) {
564 /* From this point on, we're not allowed to touch the
565 * packet any longer as its ref now belongs to the Rx
566 * ring.
567 */
568 skb = NULL;
569 sp = NULL;
570 }
571
572 nr_unacked++;
573
574 if (last) {
575 set_bit(RXRPC_CALL_RX_LAST, &call->flags);
576 if (!ack) {
577 ack = RXRPC_ACK_DELAY;
578 ack_serial = serial;
579 }
580 trace_rxrpc_receive(call, rxrpc_receive_queue_last, serial, seq);
581 } else {
582 trace_rxrpc_receive(call, rxrpc_receive_queue, serial, seq);
583 }
584
585 if (after_eq(seq, call->rx_expect_next)) {
586 if (after(seq, call->rx_expect_next)) {
587 _net("OOS %u > %u", seq, call->rx_expect_next);
588 ack = RXRPC_ACK_OUT_OF_SEQUENCE;
589 ack_serial = serial;
590 }
591 call->rx_expect_next = seq + 1;
592 }
593 if (!ack)
594 ack_serial = serial;
595 }
596
597 ack:
598 if (atomic_add_return(nr_unacked, &call->ackr_nr_unacked) > 2 && !ack)
599 ack = RXRPC_ACK_IDLE;
600
601 if (ack)
602 rxrpc_propose_ACK(call, ack, ack_serial,
603 immediate_ack, true,
604 rxrpc_propose_ack_input_data);
605 else
606 rxrpc_propose_ACK(call, RXRPC_ACK_DELAY, serial,
607 false, true,
608 rxrpc_propose_ack_input_data);
609
610 trace_rxrpc_notify_socket(call->debug_id, serial);
611 rxrpc_notify_socket(call);
612
613 unlock:
614 spin_unlock(&call->input_lock);
615 rxrpc_free_skb(skb, rxrpc_skb_freed);
616 _leave(" [queued]");
617 }
618
619 /*
620 * See if there's a cached RTT probe to complete.
621 */
rxrpc_complete_rtt_probe(struct rxrpc_call * call,ktime_t resp_time,rxrpc_serial_t acked_serial,rxrpc_serial_t ack_serial,enum rxrpc_rtt_rx_trace type)622 static void rxrpc_complete_rtt_probe(struct rxrpc_call *call,
623 ktime_t resp_time,
624 rxrpc_serial_t acked_serial,
625 rxrpc_serial_t ack_serial,
626 enum rxrpc_rtt_rx_trace type)
627 {
628 rxrpc_serial_t orig_serial;
629 unsigned long avail;
630 ktime_t sent_at;
631 bool matched = false;
632 int i;
633
634 avail = READ_ONCE(call->rtt_avail);
635 smp_rmb(); /* Read avail bits before accessing data. */
636
637 for (i = 0; i < ARRAY_SIZE(call->rtt_serial); i++) {
638 if (!test_bit(i + RXRPC_CALL_RTT_PEND_SHIFT, &avail))
639 continue;
640
641 sent_at = call->rtt_sent_at[i];
642 orig_serial = call->rtt_serial[i];
643
644 if (orig_serial == acked_serial) {
645 clear_bit(i + RXRPC_CALL_RTT_PEND_SHIFT, &call->rtt_avail);
646 smp_mb(); /* Read data before setting avail bit */
647 set_bit(i, &call->rtt_avail);
648 if (type != rxrpc_rtt_rx_cancel)
649 rxrpc_peer_add_rtt(call, type, i, acked_serial, ack_serial,
650 sent_at, resp_time);
651 else
652 trace_rxrpc_rtt_rx(call, rxrpc_rtt_rx_cancel, i,
653 orig_serial, acked_serial, 0, 0);
654 matched = true;
655 }
656
657 /* If a later serial is being acked, then mark this slot as
658 * being available.
659 */
660 if (after(acked_serial, orig_serial)) {
661 trace_rxrpc_rtt_rx(call, rxrpc_rtt_rx_obsolete, i,
662 orig_serial, acked_serial, 0, 0);
663 clear_bit(i + RXRPC_CALL_RTT_PEND_SHIFT, &call->rtt_avail);
664 smp_wmb();
665 set_bit(i, &call->rtt_avail);
666 }
667 }
668
669 if (!matched)
670 trace_rxrpc_rtt_rx(call, rxrpc_rtt_rx_lost, 9, 0, acked_serial, 0, 0);
671 }
672
673 /*
674 * Process the response to a ping that we sent to find out if we lost an ACK.
675 *
676 * If we got back a ping response that indicates a lower tx_top than what we
677 * had at the time of the ping transmission, we adjudge all the DATA packets
678 * sent between the response tx_top and the ping-time tx_top to have been lost.
679 */
rxrpc_input_check_for_lost_ack(struct rxrpc_call * call)680 static void rxrpc_input_check_for_lost_ack(struct rxrpc_call *call)
681 {
682 rxrpc_seq_t top, bottom, seq;
683 bool resend = false;
684
685 spin_lock_bh(&call->lock);
686
687 bottom = call->tx_hard_ack + 1;
688 top = call->acks_lost_top;
689 if (before(bottom, top)) {
690 for (seq = bottom; before_eq(seq, top); seq++) {
691 int ix = seq & RXRPC_RXTX_BUFF_MASK;
692 u8 annotation = call->rxtx_annotations[ix];
693 u8 anno_type = annotation & RXRPC_TX_ANNO_MASK;
694
695 if (anno_type != RXRPC_TX_ANNO_UNACK)
696 continue;
697 annotation &= ~RXRPC_TX_ANNO_MASK;
698 annotation |= RXRPC_TX_ANNO_RETRANS;
699 call->rxtx_annotations[ix] = annotation;
700 resend = true;
701 }
702 }
703
704 spin_unlock_bh(&call->lock);
705
706 if (resend && !test_and_set_bit(RXRPC_CALL_EV_RESEND, &call->events))
707 rxrpc_queue_call(call);
708 }
709
710 /*
711 * Process a ping response.
712 */
rxrpc_input_ping_response(struct rxrpc_call * call,ktime_t resp_time,rxrpc_serial_t acked_serial,rxrpc_serial_t ack_serial)713 static void rxrpc_input_ping_response(struct rxrpc_call *call,
714 ktime_t resp_time,
715 rxrpc_serial_t acked_serial,
716 rxrpc_serial_t ack_serial)
717 {
718 if (acked_serial == call->acks_lost_ping)
719 rxrpc_input_check_for_lost_ack(call);
720 }
721
722 /*
723 * Process the extra information that may be appended to an ACK packet
724 */
rxrpc_input_ackinfo(struct rxrpc_call * call,struct sk_buff * skb,struct rxrpc_ackinfo * ackinfo)725 static void rxrpc_input_ackinfo(struct rxrpc_call *call, struct sk_buff *skb,
726 struct rxrpc_ackinfo *ackinfo)
727 {
728 struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
729 struct rxrpc_peer *peer;
730 unsigned int mtu;
731 bool wake = false;
732 u32 rwind = ntohl(ackinfo->rwind);
733
734 _proto("Rx ACK %%%u Info { rx=%u max=%u rwin=%u jm=%u }",
735 sp->hdr.serial,
736 ntohl(ackinfo->rxMTU), ntohl(ackinfo->maxMTU),
737 rwind, ntohl(ackinfo->jumbo_max));
738
739 if (rwind > RXRPC_RXTX_BUFF_SIZE - 1)
740 rwind = RXRPC_RXTX_BUFF_SIZE - 1;
741 if (call->tx_winsize != rwind) {
742 if (rwind > call->tx_winsize)
743 wake = true;
744 trace_rxrpc_rx_rwind_change(call, sp->hdr.serial, rwind, wake);
745 call->tx_winsize = rwind;
746 }
747
748 if (call->cong_ssthresh > rwind)
749 call->cong_ssthresh = rwind;
750
751 mtu = min(ntohl(ackinfo->rxMTU), ntohl(ackinfo->maxMTU));
752
753 peer = call->peer;
754 if (mtu < peer->maxdata) {
755 spin_lock_bh(&peer->lock);
756 peer->maxdata = mtu;
757 peer->mtu = mtu + peer->hdrsize;
758 spin_unlock_bh(&peer->lock);
759 _net("Net MTU %u (maxdata %u)", peer->mtu, peer->maxdata);
760 }
761
762 if (wake)
763 wake_up(&call->waitq);
764 }
765
766 /*
767 * Process individual soft ACKs.
768 *
769 * Each ACK in the array corresponds to one packet and can be either an ACK or
770 * a NAK. If we get find an explicitly NAK'd packet we resend immediately;
771 * packets that lie beyond the end of the ACK list are scheduled for resend by
772 * the timer on the basis that the peer might just not have processed them at
773 * the time the ACK was sent.
774 */
rxrpc_input_soft_acks(struct rxrpc_call * call,u8 * acks,rxrpc_seq_t seq,int nr_acks,struct rxrpc_ack_summary * summary)775 static void rxrpc_input_soft_acks(struct rxrpc_call *call, u8 *acks,
776 rxrpc_seq_t seq, int nr_acks,
777 struct rxrpc_ack_summary *summary)
778 {
779 int ix;
780 u8 annotation, anno_type;
781
782 for (; nr_acks > 0; nr_acks--, seq++) {
783 ix = seq & RXRPC_RXTX_BUFF_MASK;
784 annotation = call->rxtx_annotations[ix];
785 anno_type = annotation & RXRPC_TX_ANNO_MASK;
786 annotation &= ~RXRPC_TX_ANNO_MASK;
787 switch (*acks++) {
788 case RXRPC_ACK_TYPE_ACK:
789 summary->nr_acks++;
790 if (anno_type == RXRPC_TX_ANNO_ACK)
791 continue;
792 summary->nr_new_acks++;
793 call->rxtx_annotations[ix] =
794 RXRPC_TX_ANNO_ACK | annotation;
795 break;
796 case RXRPC_ACK_TYPE_NACK:
797 if (!summary->nr_nacks &&
798 call->acks_lowest_nak != seq) {
799 call->acks_lowest_nak = seq;
800 summary->new_low_nack = true;
801 }
802 summary->nr_nacks++;
803 if (anno_type == RXRPC_TX_ANNO_NAK)
804 continue;
805 summary->nr_new_nacks++;
806 if (anno_type == RXRPC_TX_ANNO_RETRANS)
807 continue;
808 call->rxtx_annotations[ix] =
809 RXRPC_TX_ANNO_NAK | annotation;
810 break;
811 default:
812 return rxrpc_proto_abort("SFT", call, 0);
813 }
814 }
815 }
816
817 /*
818 * Return true if the ACK is valid - ie. it doesn't appear to have regressed
819 * with respect to the ack state conveyed by preceding ACKs.
820 */
rxrpc_is_ack_valid(struct rxrpc_call * call,rxrpc_seq_t first_pkt,rxrpc_seq_t prev_pkt)821 static bool rxrpc_is_ack_valid(struct rxrpc_call *call,
822 rxrpc_seq_t first_pkt, rxrpc_seq_t prev_pkt)
823 {
824 rxrpc_seq_t base = READ_ONCE(call->acks_first_seq);
825
826 if (after(first_pkt, base))
827 return true; /* The window advanced */
828
829 if (before(first_pkt, base))
830 return false; /* firstPacket regressed */
831
832 if (after_eq(prev_pkt, call->acks_prev_seq))
833 return true; /* previousPacket hasn't regressed. */
834
835 /* Some rx implementations put a serial number in previousPacket. */
836 if (after_eq(prev_pkt, base + call->tx_winsize))
837 return false;
838 return true;
839 }
840
841 /*
842 * Process an ACK packet.
843 *
844 * ack.firstPacket is the sequence number of the first soft-ACK'd/NAK'd packet
845 * in the ACK array. Anything before that is hard-ACK'd and may be discarded.
846 *
847 * A hard-ACK means that a packet has been processed and may be discarded; a
848 * soft-ACK means that the packet may be discarded and retransmission
849 * requested. A phase is complete when all packets are hard-ACK'd.
850 */
rxrpc_input_ack(struct rxrpc_call * call,struct sk_buff * skb)851 static void rxrpc_input_ack(struct rxrpc_call *call, struct sk_buff *skb)
852 {
853 struct rxrpc_ack_summary summary = { 0 };
854 struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
855 union {
856 struct rxrpc_ackpacket ack;
857 struct rxrpc_ackinfo info;
858 u8 acks[RXRPC_MAXACKS];
859 } buf;
860 rxrpc_serial_t ack_serial, acked_serial;
861 rxrpc_seq_t first_soft_ack, hard_ack, prev_pkt;
862 int nr_acks, offset, ioffset;
863
864 _enter("");
865
866 offset = sizeof(struct rxrpc_wire_header);
867 if (skb_copy_bits(skb, offset, &buf.ack, sizeof(buf.ack)) < 0) {
868 _debug("extraction failure");
869 return rxrpc_proto_abort("XAK", call, 0);
870 }
871 offset += sizeof(buf.ack);
872
873 ack_serial = sp->hdr.serial;
874 acked_serial = ntohl(buf.ack.serial);
875 first_soft_ack = ntohl(buf.ack.firstPacket);
876 prev_pkt = ntohl(buf.ack.previousPacket);
877 hard_ack = first_soft_ack - 1;
878 nr_acks = buf.ack.nAcks;
879 summary.ack_reason = (buf.ack.reason < RXRPC_ACK__INVALID ?
880 buf.ack.reason : RXRPC_ACK__INVALID);
881
882 trace_rxrpc_rx_ack(call, ack_serial, acked_serial,
883 first_soft_ack, prev_pkt,
884 summary.ack_reason, nr_acks);
885
886 switch (buf.ack.reason) {
887 case RXRPC_ACK_PING_RESPONSE:
888 rxrpc_input_ping_response(call, skb->tstamp, acked_serial,
889 ack_serial);
890 rxrpc_complete_rtt_probe(call, skb->tstamp, acked_serial, ack_serial,
891 rxrpc_rtt_rx_ping_response);
892 break;
893 case RXRPC_ACK_REQUESTED:
894 rxrpc_complete_rtt_probe(call, skb->tstamp, acked_serial, ack_serial,
895 rxrpc_rtt_rx_requested_ack);
896 break;
897 default:
898 if (acked_serial != 0)
899 rxrpc_complete_rtt_probe(call, skb->tstamp, acked_serial, ack_serial,
900 rxrpc_rtt_rx_cancel);
901 break;
902 }
903
904 if (buf.ack.reason == RXRPC_ACK_PING) {
905 _proto("Rx ACK %%%u PING Request", ack_serial);
906 rxrpc_propose_ACK(call, RXRPC_ACK_PING_RESPONSE,
907 ack_serial, true, true,
908 rxrpc_propose_ack_respond_to_ping);
909 } else if (sp->hdr.flags & RXRPC_REQUEST_ACK) {
910 rxrpc_propose_ACK(call, RXRPC_ACK_REQUESTED,
911 ack_serial, true, true,
912 rxrpc_propose_ack_respond_to_ack);
913 }
914
915 /* Discard any out-of-order or duplicate ACKs (outside lock). */
916 if (!rxrpc_is_ack_valid(call, first_soft_ack, prev_pkt)) {
917 trace_rxrpc_rx_discard_ack(call->debug_id, ack_serial,
918 first_soft_ack, call->acks_first_seq,
919 prev_pkt, call->acks_prev_seq);
920 return;
921 }
922
923 buf.info.rxMTU = 0;
924 ioffset = offset + nr_acks + 3;
925 if (skb->len >= ioffset + sizeof(buf.info) &&
926 skb_copy_bits(skb, ioffset, &buf.info, sizeof(buf.info)) < 0)
927 return rxrpc_proto_abort("XAI", call, 0);
928
929 spin_lock(&call->input_lock);
930
931 /* Discard any out-of-order or duplicate ACKs (inside lock). */
932 if (!rxrpc_is_ack_valid(call, first_soft_ack, prev_pkt)) {
933 trace_rxrpc_rx_discard_ack(call->debug_id, ack_serial,
934 first_soft_ack, call->acks_first_seq,
935 prev_pkt, call->acks_prev_seq);
936 goto out;
937 }
938 call->acks_latest_ts = skb->tstamp;
939
940 call->acks_first_seq = first_soft_ack;
941 call->acks_prev_seq = prev_pkt;
942
943 /* Parse rwind and mtu sizes if provided. */
944 if (buf.info.rxMTU)
945 rxrpc_input_ackinfo(call, skb, &buf.info);
946
947 if (first_soft_ack == 0) {
948 rxrpc_proto_abort("AK0", call, 0);
949 goto out;
950 }
951
952 /* Ignore ACKs unless we are or have just been transmitting. */
953 switch (READ_ONCE(call->state)) {
954 case RXRPC_CALL_CLIENT_SEND_REQUEST:
955 case RXRPC_CALL_CLIENT_AWAIT_REPLY:
956 case RXRPC_CALL_SERVER_SEND_REPLY:
957 case RXRPC_CALL_SERVER_AWAIT_ACK:
958 break;
959 default:
960 goto out;
961 }
962
963 if (before(hard_ack, call->tx_hard_ack) ||
964 after(hard_ack, call->tx_top)) {
965 rxrpc_proto_abort("AKW", call, 0);
966 goto out;
967 }
968 if (nr_acks > call->tx_top - hard_ack) {
969 rxrpc_proto_abort("AKN", call, 0);
970 goto out;
971 }
972
973 if (after(hard_ack, call->tx_hard_ack)) {
974 if (rxrpc_rotate_tx_window(call, hard_ack, &summary)) {
975 rxrpc_end_tx_phase(call, false, "ETA");
976 goto out;
977 }
978 }
979
980 if (nr_acks > 0) {
981 if (skb_copy_bits(skb, offset, buf.acks, nr_acks) < 0) {
982 rxrpc_proto_abort("XSA", call, 0);
983 goto out;
984 }
985 rxrpc_input_soft_acks(call, buf.acks, first_soft_ack, nr_acks,
986 &summary);
987 }
988
989 if (call->rxtx_annotations[call->tx_top & RXRPC_RXTX_BUFF_MASK] &
990 RXRPC_TX_ANNO_LAST &&
991 summary.nr_acks == call->tx_top - hard_ack &&
992 rxrpc_is_client_call(call))
993 rxrpc_propose_ACK(call, RXRPC_ACK_PING, ack_serial,
994 false, true,
995 rxrpc_propose_ack_ping_for_lost_reply);
996
997 rxrpc_congestion_management(call, skb, &summary, acked_serial);
998 out:
999 spin_unlock(&call->input_lock);
1000 }
1001
1002 /*
1003 * Process an ACKALL packet.
1004 */
rxrpc_input_ackall(struct rxrpc_call * call,struct sk_buff * skb)1005 static void rxrpc_input_ackall(struct rxrpc_call *call, struct sk_buff *skb)
1006 {
1007 struct rxrpc_ack_summary summary = { 0 };
1008 struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
1009
1010 _proto("Rx ACKALL %%%u", sp->hdr.serial);
1011
1012 spin_lock(&call->input_lock);
1013
1014 if (rxrpc_rotate_tx_window(call, call->tx_top, &summary))
1015 rxrpc_end_tx_phase(call, false, "ETL");
1016
1017 spin_unlock(&call->input_lock);
1018 }
1019
1020 /*
1021 * Process an ABORT packet directed at a call.
1022 */
rxrpc_input_abort(struct rxrpc_call * call,struct sk_buff * skb)1023 static void rxrpc_input_abort(struct rxrpc_call *call, struct sk_buff *skb)
1024 {
1025 struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
1026 __be32 wtmp;
1027 u32 abort_code = RX_CALL_DEAD;
1028
1029 _enter("");
1030
1031 if (skb->len >= 4 &&
1032 skb_copy_bits(skb, sizeof(struct rxrpc_wire_header),
1033 &wtmp, sizeof(wtmp)) >= 0)
1034 abort_code = ntohl(wtmp);
1035
1036 trace_rxrpc_rx_abort(call, sp->hdr.serial, abort_code);
1037
1038 _proto("Rx ABORT %%%u { %x }", sp->hdr.serial, abort_code);
1039
1040 rxrpc_set_call_completion(call, RXRPC_CALL_REMOTELY_ABORTED,
1041 abort_code, -ECONNABORTED);
1042 }
1043
1044 /*
1045 * Process an incoming call packet.
1046 */
rxrpc_input_call_packet(struct rxrpc_call * call,struct sk_buff * skb)1047 static void rxrpc_input_call_packet(struct rxrpc_call *call,
1048 struct sk_buff *skb)
1049 {
1050 struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
1051 unsigned long timo;
1052
1053 _enter("%p,%p", call, skb);
1054
1055 timo = READ_ONCE(call->next_rx_timo);
1056 if (timo) {
1057 unsigned long now = jiffies, expect_rx_by;
1058
1059 expect_rx_by = now + timo;
1060 WRITE_ONCE(call->expect_rx_by, expect_rx_by);
1061 rxrpc_reduce_call_timer(call, expect_rx_by, now,
1062 rxrpc_timer_set_for_normal);
1063 }
1064
1065 switch (sp->hdr.type) {
1066 case RXRPC_PACKET_TYPE_DATA:
1067 rxrpc_input_data(call, skb);
1068 goto no_free;
1069
1070 case RXRPC_PACKET_TYPE_ACK:
1071 rxrpc_input_ack(call, skb);
1072 break;
1073
1074 case RXRPC_PACKET_TYPE_BUSY:
1075 _proto("Rx BUSY %%%u", sp->hdr.serial);
1076
1077 /* Just ignore BUSY packets from the server; the retry and
1078 * lifespan timers will take care of business. BUSY packets
1079 * from the client don't make sense.
1080 */
1081 break;
1082
1083 case RXRPC_PACKET_TYPE_ABORT:
1084 rxrpc_input_abort(call, skb);
1085 break;
1086
1087 case RXRPC_PACKET_TYPE_ACKALL:
1088 rxrpc_input_ackall(call, skb);
1089 break;
1090
1091 default:
1092 break;
1093 }
1094
1095 rxrpc_free_skb(skb, rxrpc_skb_freed);
1096 no_free:
1097 _leave("");
1098 }
1099
1100 /*
1101 * Handle a new service call on a channel implicitly completing the preceding
1102 * call on that channel. This does not apply to client conns.
1103 *
1104 * TODO: If callNumber > call_id + 1, renegotiate security.
1105 */
rxrpc_input_implicit_end_call(struct rxrpc_sock * rx,struct rxrpc_connection * conn,struct rxrpc_call * call)1106 static void rxrpc_input_implicit_end_call(struct rxrpc_sock *rx,
1107 struct rxrpc_connection *conn,
1108 struct rxrpc_call *call)
1109 {
1110 switch (READ_ONCE(call->state)) {
1111 case RXRPC_CALL_SERVER_AWAIT_ACK:
1112 rxrpc_call_completed(call);
1113 fallthrough;
1114 case RXRPC_CALL_COMPLETE:
1115 break;
1116 default:
1117 if (rxrpc_abort_call("IMP", call, 0, RX_CALL_DEAD, -ESHUTDOWN)) {
1118 set_bit(RXRPC_CALL_EV_ABORT, &call->events);
1119 rxrpc_queue_call(call);
1120 }
1121 trace_rxrpc_improper_term(call);
1122 break;
1123 }
1124
1125 spin_lock(&rx->incoming_lock);
1126 __rxrpc_disconnect_call(conn, call);
1127 spin_unlock(&rx->incoming_lock);
1128 }
1129
1130 /*
1131 * post connection-level events to the connection
1132 * - this includes challenges, responses, some aborts and call terminal packet
1133 * retransmission.
1134 */
rxrpc_post_packet_to_conn(struct rxrpc_connection * conn,struct sk_buff * skb)1135 static void rxrpc_post_packet_to_conn(struct rxrpc_connection *conn,
1136 struct sk_buff *skb)
1137 {
1138 _enter("%p,%p", conn, skb);
1139
1140 skb_queue_tail(&conn->rx_queue, skb);
1141 rxrpc_queue_conn(conn);
1142 }
1143
1144 /*
1145 * post endpoint-level events to the local endpoint
1146 * - this includes debug and version messages
1147 */
rxrpc_post_packet_to_local(struct rxrpc_local * local,struct sk_buff * skb)1148 static void rxrpc_post_packet_to_local(struct rxrpc_local *local,
1149 struct sk_buff *skb)
1150 {
1151 _enter("%p,%p", local, skb);
1152
1153 if (rxrpc_get_local_maybe(local)) {
1154 skb_queue_tail(&local->event_queue, skb);
1155 rxrpc_queue_local(local);
1156 } else {
1157 rxrpc_free_skb(skb, rxrpc_skb_freed);
1158 }
1159 }
1160
1161 /*
1162 * put a packet up for transport-level abort
1163 */
rxrpc_reject_packet(struct rxrpc_local * local,struct sk_buff * skb)1164 static void rxrpc_reject_packet(struct rxrpc_local *local, struct sk_buff *skb)
1165 {
1166 if (rxrpc_get_local_maybe(local)) {
1167 skb_queue_tail(&local->reject_queue, skb);
1168 rxrpc_queue_local(local);
1169 } else {
1170 rxrpc_free_skb(skb, rxrpc_skb_freed);
1171 }
1172 }
1173
1174 /*
1175 * Extract the wire header from a packet and translate the byte order.
1176 */
1177 static noinline
rxrpc_extract_header(struct rxrpc_skb_priv * sp,struct sk_buff * skb)1178 int rxrpc_extract_header(struct rxrpc_skb_priv *sp, struct sk_buff *skb)
1179 {
1180 struct rxrpc_wire_header whdr;
1181
1182 /* dig out the RxRPC connection details */
1183 if (skb_copy_bits(skb, 0, &whdr, sizeof(whdr)) < 0) {
1184 trace_rxrpc_rx_eproto(NULL, sp->hdr.serial,
1185 tracepoint_string("bad_hdr"));
1186 return -EBADMSG;
1187 }
1188
1189 memset(sp, 0, sizeof(*sp));
1190 sp->hdr.epoch = ntohl(whdr.epoch);
1191 sp->hdr.cid = ntohl(whdr.cid);
1192 sp->hdr.callNumber = ntohl(whdr.callNumber);
1193 sp->hdr.seq = ntohl(whdr.seq);
1194 sp->hdr.serial = ntohl(whdr.serial);
1195 sp->hdr.flags = whdr.flags;
1196 sp->hdr.type = whdr.type;
1197 sp->hdr.userStatus = whdr.userStatus;
1198 sp->hdr.securityIndex = whdr.securityIndex;
1199 sp->hdr._rsvd = ntohs(whdr._rsvd);
1200 sp->hdr.serviceId = ntohs(whdr.serviceId);
1201 return 0;
1202 }
1203
1204 /*
1205 * handle data received on the local endpoint
1206 * - may be called in interrupt context
1207 *
1208 * [!] Note that as this is called from the encap_rcv hook, the socket is not
1209 * held locked by the caller and nothing prevents sk_user_data on the UDP from
1210 * being cleared in the middle of processing this function.
1211 *
1212 * Called with the RCU read lock held from the IP layer via UDP.
1213 */
rxrpc_input_packet(struct sock * udp_sk,struct sk_buff * skb)1214 int rxrpc_input_packet(struct sock *udp_sk, struct sk_buff *skb)
1215 {
1216 struct rxrpc_local *local = rcu_dereference_sk_user_data(udp_sk);
1217 struct rxrpc_connection *conn;
1218 struct rxrpc_channel *chan;
1219 struct rxrpc_call *call = NULL;
1220 struct rxrpc_skb_priv *sp;
1221 struct rxrpc_peer *peer = NULL;
1222 struct rxrpc_sock *rx = NULL;
1223 unsigned int channel;
1224
1225 _enter("%p", udp_sk);
1226
1227 if (unlikely(!local)) {
1228 kfree_skb(skb);
1229 return 0;
1230 }
1231 if (skb->tstamp == 0)
1232 skb->tstamp = ktime_get_real();
1233
1234 rxrpc_new_skb(skb, rxrpc_skb_received);
1235
1236 skb_pull(skb, sizeof(struct udphdr));
1237
1238 /* The UDP protocol already released all skb resources;
1239 * we are free to add our own data there.
1240 */
1241 sp = rxrpc_skb(skb);
1242
1243 /* dig out the RxRPC connection details */
1244 if (rxrpc_extract_header(sp, skb) < 0)
1245 goto bad_message;
1246
1247 if (IS_ENABLED(CONFIG_AF_RXRPC_INJECT_LOSS)) {
1248 static int lose;
1249 if ((lose++ & 7) == 7) {
1250 trace_rxrpc_rx_lose(sp);
1251 rxrpc_free_skb(skb, rxrpc_skb_lost);
1252 return 0;
1253 }
1254 }
1255
1256 if (skb->tstamp == 0)
1257 skb->tstamp = ktime_get_real();
1258 trace_rxrpc_rx_packet(sp);
1259
1260 switch (sp->hdr.type) {
1261 case RXRPC_PACKET_TYPE_VERSION:
1262 if (rxrpc_to_client(sp))
1263 goto discard;
1264 rxrpc_post_packet_to_local(local, skb);
1265 goto out;
1266
1267 case RXRPC_PACKET_TYPE_BUSY:
1268 if (rxrpc_to_server(sp))
1269 goto discard;
1270 fallthrough;
1271 case RXRPC_PACKET_TYPE_ACK:
1272 case RXRPC_PACKET_TYPE_ACKALL:
1273 if (sp->hdr.callNumber == 0)
1274 goto bad_message;
1275 fallthrough;
1276 case RXRPC_PACKET_TYPE_ABORT:
1277 break;
1278
1279 case RXRPC_PACKET_TYPE_DATA:
1280 if (sp->hdr.callNumber == 0 ||
1281 sp->hdr.seq == 0)
1282 goto bad_message;
1283 if (!rxrpc_validate_data(skb))
1284 goto bad_message;
1285
1286 /* Unshare the packet so that it can be modified for in-place
1287 * decryption.
1288 */
1289 if (sp->hdr.securityIndex != 0) {
1290 struct sk_buff *nskb = skb_unshare(skb, GFP_ATOMIC);
1291 if (!nskb) {
1292 rxrpc_eaten_skb(skb, rxrpc_skb_unshared_nomem);
1293 goto out;
1294 }
1295
1296 if (nskb != skb) {
1297 rxrpc_eaten_skb(skb, rxrpc_skb_received);
1298 skb = nskb;
1299 rxrpc_new_skb(skb, rxrpc_skb_unshared);
1300 sp = rxrpc_skb(skb);
1301 }
1302 }
1303 break;
1304
1305 case RXRPC_PACKET_TYPE_CHALLENGE:
1306 if (rxrpc_to_server(sp))
1307 goto discard;
1308 break;
1309 case RXRPC_PACKET_TYPE_RESPONSE:
1310 if (rxrpc_to_client(sp))
1311 goto discard;
1312 break;
1313
1314 /* Packet types 9-11 should just be ignored. */
1315 case RXRPC_PACKET_TYPE_PARAMS:
1316 case RXRPC_PACKET_TYPE_10:
1317 case RXRPC_PACKET_TYPE_11:
1318 goto discard;
1319
1320 default:
1321 _proto("Rx Bad Packet Type %u", sp->hdr.type);
1322 goto bad_message;
1323 }
1324
1325 if (sp->hdr.serviceId == 0)
1326 goto bad_message;
1327
1328 if (rxrpc_to_server(sp)) {
1329 /* Weed out packets to services we're not offering. Packets
1330 * that would begin a call are explicitly rejected and the rest
1331 * are just discarded.
1332 */
1333 rx = rcu_dereference(local->service);
1334 if (!rx || (sp->hdr.serviceId != rx->srx.srx_service &&
1335 sp->hdr.serviceId != rx->second_service)) {
1336 if (sp->hdr.type == RXRPC_PACKET_TYPE_DATA &&
1337 sp->hdr.seq == 1)
1338 goto unsupported_service;
1339 goto discard;
1340 }
1341 }
1342
1343 conn = rxrpc_find_connection_rcu(local, skb, &peer);
1344 if (conn) {
1345 if (sp->hdr.securityIndex != conn->security_ix)
1346 goto wrong_security;
1347
1348 if (sp->hdr.serviceId != conn->service_id) {
1349 int old_id;
1350
1351 if (!test_bit(RXRPC_CONN_PROBING_FOR_UPGRADE, &conn->flags))
1352 goto reupgrade;
1353 old_id = cmpxchg(&conn->service_id, conn->params.service_id,
1354 sp->hdr.serviceId);
1355
1356 if (old_id != conn->params.service_id &&
1357 old_id != sp->hdr.serviceId)
1358 goto reupgrade;
1359 }
1360
1361 if (sp->hdr.callNumber == 0) {
1362 /* Connection-level packet */
1363 _debug("CONN %p {%d}", conn, conn->debug_id);
1364 rxrpc_post_packet_to_conn(conn, skb);
1365 goto out;
1366 }
1367
1368 if ((int)sp->hdr.serial - (int)conn->hi_serial > 0)
1369 conn->hi_serial = sp->hdr.serial;
1370
1371 /* Call-bound packets are routed by connection channel. */
1372 channel = sp->hdr.cid & RXRPC_CHANNELMASK;
1373 chan = &conn->channels[channel];
1374
1375 /* Ignore really old calls */
1376 if (sp->hdr.callNumber < chan->last_call)
1377 goto discard;
1378
1379 if (sp->hdr.callNumber == chan->last_call) {
1380 if (chan->call ||
1381 sp->hdr.type == RXRPC_PACKET_TYPE_ABORT)
1382 goto discard;
1383
1384 /* For the previous service call, if completed
1385 * successfully, we discard all further packets.
1386 */
1387 if (rxrpc_conn_is_service(conn) &&
1388 chan->last_type == RXRPC_PACKET_TYPE_ACK)
1389 goto discard;
1390
1391 /* But otherwise we need to retransmit the final packet
1392 * from data cached in the connection record.
1393 */
1394 if (sp->hdr.type == RXRPC_PACKET_TYPE_DATA)
1395 trace_rxrpc_rx_data(chan->call_debug_id,
1396 sp->hdr.seq,
1397 sp->hdr.serial,
1398 sp->hdr.flags, 0);
1399 rxrpc_post_packet_to_conn(conn, skb);
1400 goto out;
1401 }
1402
1403 call = rcu_dereference(chan->call);
1404
1405 if (sp->hdr.callNumber > chan->call_id) {
1406 if (rxrpc_to_client(sp))
1407 goto reject_packet;
1408 if (call)
1409 rxrpc_input_implicit_end_call(rx, conn, call);
1410 call = NULL;
1411 }
1412
1413 if (call) {
1414 if (sp->hdr.serviceId != call->service_id)
1415 call->service_id = sp->hdr.serviceId;
1416 if ((int)sp->hdr.serial - (int)call->rx_serial > 0)
1417 call->rx_serial = sp->hdr.serial;
1418 if (!test_bit(RXRPC_CALL_RX_HEARD, &call->flags))
1419 set_bit(RXRPC_CALL_RX_HEARD, &call->flags);
1420 }
1421 }
1422
1423 if (!call || refcount_read(&call->ref) == 0) {
1424 if (rxrpc_to_client(sp) ||
1425 sp->hdr.type != RXRPC_PACKET_TYPE_DATA)
1426 goto bad_message;
1427 if (sp->hdr.seq != 1)
1428 goto discard;
1429 call = rxrpc_new_incoming_call(local, rx, skb);
1430 if (!call)
1431 goto reject_packet;
1432 }
1433
1434 /* Process a call packet; this either discards or passes on the ref
1435 * elsewhere.
1436 */
1437 rxrpc_input_call_packet(call, skb);
1438 goto out;
1439
1440 discard:
1441 rxrpc_free_skb(skb, rxrpc_skb_freed);
1442 out:
1443 trace_rxrpc_rx_done(0, 0);
1444 return 0;
1445
1446 wrong_security:
1447 trace_rxrpc_abort(0, "SEC", sp->hdr.cid, sp->hdr.callNumber, sp->hdr.seq,
1448 RXKADINCONSISTENCY, EBADMSG);
1449 skb->priority = RXKADINCONSISTENCY;
1450 goto post_abort;
1451
1452 unsupported_service:
1453 trace_rxrpc_abort(0, "INV", sp->hdr.cid, sp->hdr.callNumber, sp->hdr.seq,
1454 RX_INVALID_OPERATION, EOPNOTSUPP);
1455 skb->priority = RX_INVALID_OPERATION;
1456 goto post_abort;
1457
1458 reupgrade:
1459 trace_rxrpc_abort(0, "UPG", sp->hdr.cid, sp->hdr.callNumber, sp->hdr.seq,
1460 RX_PROTOCOL_ERROR, EBADMSG);
1461 goto protocol_error;
1462
1463 bad_message:
1464 trace_rxrpc_abort(0, "BAD", sp->hdr.cid, sp->hdr.callNumber, sp->hdr.seq,
1465 RX_PROTOCOL_ERROR, EBADMSG);
1466 protocol_error:
1467 skb->priority = RX_PROTOCOL_ERROR;
1468 post_abort:
1469 skb->mark = RXRPC_SKB_MARK_REJECT_ABORT;
1470 reject_packet:
1471 trace_rxrpc_rx_done(skb->mark, skb->priority);
1472 rxrpc_reject_packet(local, skb);
1473 _leave(" [badmsg]");
1474 return 0;
1475 }
1476