rxrpc: Use rxrpc_free_skb() rather than rxrpc_lose_skb()
[linux-2.6-block.git] / net / rxrpc / input.c
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_mark_not_on_list(skb);
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                 trace_rxrpc_transmit(call, rxrpc_transmit_await_reply);
302         } else {
303                 trace_rxrpc_transmit(call, rxrpc_transmit_end);
304         }
305         _leave(" = ok");
306         return true;
307
308 bad_state:
309         write_unlock(&call->state_lock);
310         kdebug("end_tx %s", rxrpc_call_states[call->state]);
311         rxrpc_proto_abort(abort_why, call, call->tx_top);
312         return false;
313 }
314
315 /*
316  * Begin the reply reception phase of a call.
317  */
318 static bool rxrpc_receiving_reply(struct rxrpc_call *call)
319 {
320         struct rxrpc_ack_summary summary = { 0 };
321         unsigned long now, timo;
322         rxrpc_seq_t top = READ_ONCE(call->tx_top);
323
324         if (call->ackr_reason) {
325                 spin_lock_bh(&call->lock);
326                 call->ackr_reason = 0;
327                 spin_unlock_bh(&call->lock);
328                 now = jiffies;
329                 timo = now + MAX_JIFFY_OFFSET;
330                 WRITE_ONCE(call->resend_at, timo);
331                 WRITE_ONCE(call->ack_at, timo);
332                 trace_rxrpc_timer(call, rxrpc_timer_init_for_reply, now);
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         if (call->state == RXRPC_CALL_SERVER_RECV_REQUEST) {
443                 unsigned long timo = READ_ONCE(call->next_req_timo);
444                 unsigned long now, expect_req_by;
445
446                 if (timo) {
447                         now = jiffies;
448                         expect_req_by = now + timo;
449                         WRITE_ONCE(call->expect_req_by, expect_req_by);
450                         rxrpc_reduce_call_timer(call, expect_req_by, now,
451                                                 rxrpc_timer_set_for_idle);
452                 }
453         }
454
455         /* Received data implicitly ACKs all of the request packets we sent
456          * when we're acting as a client.
457          */
458         if ((state == RXRPC_CALL_CLIENT_SEND_REQUEST ||
459              state == RXRPC_CALL_CLIENT_AWAIT_REPLY) &&
460             !rxrpc_receiving_reply(call))
461                 return;
462
463         call->ackr_prev_seq = seq;
464
465         hard_ack = READ_ONCE(call->rx_hard_ack);
466         if (after(seq, hard_ack + call->rx_winsize)) {
467                 ack = RXRPC_ACK_EXCEEDS_WINDOW;
468                 ack_serial = serial;
469                 goto ack;
470         }
471
472         flags = sp->hdr.flags;
473         if (flags & RXRPC_JUMBO_PACKET) {
474                 if (call->nr_jumbo_bad > 3) {
475                         ack = RXRPC_ACK_NOSPACE;
476                         ack_serial = serial;
477                         goto ack;
478                 }
479                 annotation = 1;
480         }
481
482 next_subpacket:
483         queued = false;
484         ix = seq & RXRPC_RXTX_BUFF_MASK;
485         len = skb->len;
486         if (flags & RXRPC_JUMBO_PACKET)
487                 len = RXRPC_JUMBO_DATALEN;
488
489         if (flags & RXRPC_LAST_PACKET) {
490                 if (test_bit(RXRPC_CALL_RX_LAST, &call->flags) &&
491                     seq != call->rx_top)
492                         return rxrpc_proto_abort("LSN", call, seq);
493         } else {
494                 if (test_bit(RXRPC_CALL_RX_LAST, &call->flags) &&
495                     after_eq(seq, call->rx_top))
496                         return rxrpc_proto_abort("LSA", call, seq);
497         }
498
499         trace_rxrpc_rx_data(call->debug_id, seq, serial, flags, annotation);
500         if (before_eq(seq, hard_ack)) {
501                 ack = RXRPC_ACK_DUPLICATE;
502                 ack_serial = serial;
503                 goto skip;
504         }
505
506         if (flags & RXRPC_REQUEST_ACK && !ack) {
507                 ack = RXRPC_ACK_REQUESTED;
508                 ack_serial = serial;
509         }
510
511         if (call->rxtx_buffer[ix]) {
512                 rxrpc_input_dup_data(call, seq, annotation, &jumbo_bad);
513                 if (ack != RXRPC_ACK_DUPLICATE) {
514                         ack = RXRPC_ACK_DUPLICATE;
515                         ack_serial = serial;
516                 }
517                 immediate_ack = true;
518                 goto skip;
519         }
520
521         /* Queue the packet.  We use a couple of memory barriers here as need
522          * to make sure that rx_top is perceived to be set after the buffer
523          * pointer and that the buffer pointer is set after the annotation and
524          * the skb data.
525          *
526          * Barriers against rxrpc_recvmsg_data() and rxrpc_rotate_rx_window()
527          * and also rxrpc_fill_out_ack().
528          */
529         rxrpc_get_skb(skb, rxrpc_skb_rx_got);
530         call->rxtx_annotations[ix] = annotation;
531         smp_wmb();
532         call->rxtx_buffer[ix] = skb;
533         if (after(seq, call->rx_top)) {
534                 smp_store_release(&call->rx_top, seq);
535         } else if (before(seq, call->rx_top)) {
536                 /* Send an immediate ACK if we fill in a hole */
537                 if (!ack) {
538                         ack = RXRPC_ACK_DELAY;
539                         ack_serial = serial;
540                 }
541                 immediate_ack = true;
542         }
543         if (flags & RXRPC_LAST_PACKET) {
544                 set_bit(RXRPC_CALL_RX_LAST, &call->flags);
545                 trace_rxrpc_receive(call, rxrpc_receive_queue_last, serial, seq);
546         } else {
547                 trace_rxrpc_receive(call, rxrpc_receive_queue, serial, seq);
548         }
549         queued = true;
550
551         if (after_eq(seq, call->rx_expect_next)) {
552                 if (after(seq, call->rx_expect_next)) {
553                         _net("OOS %u > %u", seq, call->rx_expect_next);
554                         ack = RXRPC_ACK_OUT_OF_SEQUENCE;
555                         ack_serial = serial;
556                 }
557                 call->rx_expect_next = seq + 1;
558         }
559
560 skip:
561         offset += len;
562         if (flags & RXRPC_JUMBO_PACKET) {
563                 if (skb_copy_bits(skb, offset, &flags, 1) < 0)
564                         return rxrpc_proto_abort("XJF", call, seq);
565                 offset += sizeof(struct rxrpc_jumbo_header);
566                 seq++;
567                 serial++;
568                 annotation++;
569                 if (flags & RXRPC_JUMBO_PACKET)
570                         annotation |= RXRPC_RX_ANNO_JLAST;
571                 if (after(seq, hard_ack + call->rx_winsize)) {
572                         ack = RXRPC_ACK_EXCEEDS_WINDOW;
573                         ack_serial = serial;
574                         if (!jumbo_bad) {
575                                 call->nr_jumbo_bad++;
576                                 jumbo_bad = true;
577                         }
578                         goto ack;
579                 }
580
581                 _proto("Rx DATA Jumbo %%%u", serial);
582                 goto next_subpacket;
583         }
584
585         if (queued && flags & RXRPC_LAST_PACKET && !ack) {
586                 ack = RXRPC_ACK_DELAY;
587                 ack_serial = serial;
588         }
589
590 ack:
591         if (ack)
592                 rxrpc_propose_ACK(call, ack, skew, ack_serial,
593                                   immediate_ack, true,
594                                   rxrpc_propose_ack_input_data);
595         else
596                 rxrpc_propose_ACK(call, RXRPC_ACK_DELAY, skew, serial,
597                                   false, true,
598                                   rxrpc_propose_ack_input_data);
599
600         if (sp->hdr.seq == READ_ONCE(call->rx_hard_ack) + 1) {
601                 trace_rxrpc_notify_socket(call->debug_id, serial);
602                 rxrpc_notify_socket(call);
603         }
604         _leave(" [queued]");
605 }
606
607 /*
608  * Process a requested ACK.
609  */
610 static void rxrpc_input_requested_ack(struct rxrpc_call *call,
611                                       ktime_t resp_time,
612                                       rxrpc_serial_t orig_serial,
613                                       rxrpc_serial_t ack_serial)
614 {
615         struct rxrpc_skb_priv *sp;
616         struct sk_buff *skb;
617         ktime_t sent_at;
618         int ix;
619
620         for (ix = 0; ix < RXRPC_RXTX_BUFF_SIZE; ix++) {
621                 skb = call->rxtx_buffer[ix];
622                 if (!skb)
623                         continue;
624
625                 sent_at = skb->tstamp;
626                 smp_rmb(); /* Read timestamp before serial. */
627                 sp = rxrpc_skb(skb);
628                 if (sp->hdr.serial != orig_serial)
629                         continue;
630                 goto found;
631         }
632
633         return;
634
635 found:
636         rxrpc_peer_add_rtt(call, rxrpc_rtt_rx_requested_ack,
637                            orig_serial, ack_serial, sent_at, resp_time);
638 }
639
640 /*
641  * Process the response to a ping that we sent to find out if we lost an ACK.
642  *
643  * If we got back a ping response that indicates a lower tx_top than what we
644  * had at the time of the ping transmission, we adjudge all the DATA packets
645  * sent between the response tx_top and the ping-time tx_top to have been lost.
646  */
647 static void rxrpc_input_check_for_lost_ack(struct rxrpc_call *call)
648 {
649         rxrpc_seq_t top, bottom, seq;
650         bool resend = false;
651
652         spin_lock_bh(&call->lock);
653
654         bottom = call->tx_hard_ack + 1;
655         top = call->acks_lost_top;
656         if (before(bottom, top)) {
657                 for (seq = bottom; before_eq(seq, top); seq++) {
658                         int ix = seq & RXRPC_RXTX_BUFF_MASK;
659                         u8 annotation = call->rxtx_annotations[ix];
660                         u8 anno_type = annotation & RXRPC_TX_ANNO_MASK;
661
662                         if (anno_type != RXRPC_TX_ANNO_UNACK)
663                                 continue;
664                         annotation &= ~RXRPC_TX_ANNO_MASK;
665                         annotation |= RXRPC_TX_ANNO_RETRANS;
666                         call->rxtx_annotations[ix] = annotation;
667                         resend = true;
668                 }
669         }
670
671         spin_unlock_bh(&call->lock);
672
673         if (resend && !test_and_set_bit(RXRPC_CALL_EV_RESEND, &call->events))
674                 rxrpc_queue_call(call);
675 }
676
677 /*
678  * Process a ping response.
679  */
680 static void rxrpc_input_ping_response(struct rxrpc_call *call,
681                                       ktime_t resp_time,
682                                       rxrpc_serial_t orig_serial,
683                                       rxrpc_serial_t ack_serial)
684 {
685         rxrpc_serial_t ping_serial;
686         ktime_t ping_time;
687
688         ping_time = call->ping_time;
689         smp_rmb();
690         ping_serial = call->ping_serial;
691
692         if (orig_serial == call->acks_lost_ping)
693                 rxrpc_input_check_for_lost_ack(call);
694
695         if (!test_bit(RXRPC_CALL_PINGING, &call->flags) ||
696             before(orig_serial, ping_serial))
697                 return;
698         clear_bit(RXRPC_CALL_PINGING, &call->flags);
699         if (after(orig_serial, ping_serial))
700                 return;
701
702         rxrpc_peer_add_rtt(call, rxrpc_rtt_rx_ping_response,
703                            orig_serial, ack_serial, ping_time, resp_time);
704 }
705
706 /*
707  * Process the extra information that may be appended to an ACK packet
708  */
709 static void rxrpc_input_ackinfo(struct rxrpc_call *call, struct sk_buff *skb,
710                                 struct rxrpc_ackinfo *ackinfo)
711 {
712         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
713         struct rxrpc_peer *peer;
714         unsigned int mtu;
715         bool wake = false;
716         u32 rwind = ntohl(ackinfo->rwind);
717
718         _proto("Rx ACK %%%u Info { rx=%u max=%u rwin=%u jm=%u }",
719                sp->hdr.serial,
720                ntohl(ackinfo->rxMTU), ntohl(ackinfo->maxMTU),
721                rwind, ntohl(ackinfo->jumbo_max));
722
723         if (call->tx_winsize != rwind) {
724                 if (rwind > RXRPC_RXTX_BUFF_SIZE - 1)
725                         rwind = RXRPC_RXTX_BUFF_SIZE - 1;
726                 if (rwind > call->tx_winsize)
727                         wake = true;
728                 trace_rxrpc_rx_rwind_change(call, sp->hdr.serial,
729                                             ntohl(ackinfo->rwind), wake);
730                 call->tx_winsize = rwind;
731         }
732
733         if (call->cong_ssthresh > rwind)
734                 call->cong_ssthresh = rwind;
735
736         mtu = min(ntohl(ackinfo->rxMTU), ntohl(ackinfo->maxMTU));
737
738         peer = call->peer;
739         if (mtu < peer->maxdata) {
740                 spin_lock_bh(&peer->lock);
741                 peer->maxdata = mtu;
742                 peer->mtu = mtu + peer->hdrsize;
743                 spin_unlock_bh(&peer->lock);
744                 _net("Net MTU %u (maxdata %u)", peer->mtu, peer->maxdata);
745         }
746
747         if (wake)
748                 wake_up(&call->waitq);
749 }
750
751 /*
752  * Process individual soft ACKs.
753  *
754  * Each ACK in the array corresponds to one packet and can be either an ACK or
755  * a NAK.  If we get find an explicitly NAK'd packet we resend immediately;
756  * packets that lie beyond the end of the ACK list are scheduled for resend by
757  * the timer on the basis that the peer might just not have processed them at
758  * the time the ACK was sent.
759  */
760 static void rxrpc_input_soft_acks(struct rxrpc_call *call, u8 *acks,
761                                   rxrpc_seq_t seq, int nr_acks,
762                                   struct rxrpc_ack_summary *summary)
763 {
764         int ix;
765         u8 annotation, anno_type;
766
767         for (; nr_acks > 0; nr_acks--, seq++) {
768                 ix = seq & RXRPC_RXTX_BUFF_MASK;
769                 annotation = call->rxtx_annotations[ix];
770                 anno_type = annotation & RXRPC_TX_ANNO_MASK;
771                 annotation &= ~RXRPC_TX_ANNO_MASK;
772                 switch (*acks++) {
773                 case RXRPC_ACK_TYPE_ACK:
774                         summary->nr_acks++;
775                         if (anno_type == RXRPC_TX_ANNO_ACK)
776                                 continue;
777                         summary->nr_new_acks++;
778                         call->rxtx_annotations[ix] =
779                                 RXRPC_TX_ANNO_ACK | annotation;
780                         break;
781                 case RXRPC_ACK_TYPE_NACK:
782                         if (!summary->nr_nacks &&
783                             call->acks_lowest_nak != seq) {
784                                 call->acks_lowest_nak = seq;
785                                 summary->new_low_nack = true;
786                         }
787                         summary->nr_nacks++;
788                         if (anno_type == RXRPC_TX_ANNO_NAK)
789                                 continue;
790                         summary->nr_new_nacks++;
791                         if (anno_type == RXRPC_TX_ANNO_RETRANS)
792                                 continue;
793                         call->rxtx_annotations[ix] =
794                                 RXRPC_TX_ANNO_NAK | annotation;
795                         break;
796                 default:
797                         return rxrpc_proto_abort("SFT", call, 0);
798                 }
799         }
800 }
801
802 /*
803  * Process an ACK packet.
804  *
805  * ack.firstPacket is the sequence number of the first soft-ACK'd/NAK'd packet
806  * in the ACK array.  Anything before that is hard-ACK'd and may be discarded.
807  *
808  * A hard-ACK means that a packet has been processed and may be discarded; a
809  * soft-ACK means that the packet may be discarded and retransmission
810  * requested.  A phase is complete when all packets are hard-ACK'd.
811  */
812 static void rxrpc_input_ack(struct rxrpc_call *call, struct sk_buff *skb,
813                             u16 skew)
814 {
815         struct rxrpc_ack_summary summary = { 0 };
816         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
817         union {
818                 struct rxrpc_ackpacket ack;
819                 struct rxrpc_ackinfo info;
820                 u8 acks[RXRPC_MAXACKS];
821         } buf;
822         rxrpc_serial_t acked_serial;
823         rxrpc_seq_t first_soft_ack, hard_ack;
824         int nr_acks, offset, ioffset;
825
826         _enter("");
827
828         offset = sizeof(struct rxrpc_wire_header);
829         if (skb_copy_bits(skb, offset, &buf.ack, sizeof(buf.ack)) < 0) {
830                 _debug("extraction failure");
831                 return rxrpc_proto_abort("XAK", call, 0);
832         }
833         offset += sizeof(buf.ack);
834
835         acked_serial = ntohl(buf.ack.serial);
836         first_soft_ack = ntohl(buf.ack.firstPacket);
837         hard_ack = first_soft_ack - 1;
838         nr_acks = buf.ack.nAcks;
839         summary.ack_reason = (buf.ack.reason < RXRPC_ACK__INVALID ?
840                               buf.ack.reason : RXRPC_ACK__INVALID);
841
842         trace_rxrpc_rx_ack(call, sp->hdr.serial, acked_serial,
843                            first_soft_ack, ntohl(buf.ack.previousPacket),
844                            summary.ack_reason, nr_acks);
845
846         if (buf.ack.reason == RXRPC_ACK_PING_RESPONSE)
847                 rxrpc_input_ping_response(call, skb->tstamp, acked_serial,
848                                           sp->hdr.serial);
849         if (buf.ack.reason == RXRPC_ACK_REQUESTED)
850                 rxrpc_input_requested_ack(call, skb->tstamp, acked_serial,
851                                           sp->hdr.serial);
852
853         if (buf.ack.reason == RXRPC_ACK_PING) {
854                 _proto("Rx ACK %%%u PING Request", sp->hdr.serial);
855                 rxrpc_propose_ACK(call, RXRPC_ACK_PING_RESPONSE,
856                                   skew, sp->hdr.serial, true, true,
857                                   rxrpc_propose_ack_respond_to_ping);
858         } else if (sp->hdr.flags & RXRPC_REQUEST_ACK) {
859                 rxrpc_propose_ACK(call, RXRPC_ACK_REQUESTED,
860                                   skew, sp->hdr.serial, true, true,
861                                   rxrpc_propose_ack_respond_to_ack);
862         }
863
864         ioffset = offset + nr_acks + 3;
865         if (skb->len >= ioffset + sizeof(buf.info)) {
866                 if (skb_copy_bits(skb, ioffset, &buf.info, sizeof(buf.info)) < 0)
867                         return rxrpc_proto_abort("XAI", call, 0);
868                 rxrpc_input_ackinfo(call, skb, &buf.info);
869         }
870
871         if (first_soft_ack == 0)
872                 return rxrpc_proto_abort("AK0", call, 0);
873
874         /* Ignore ACKs unless we are or have just been transmitting. */
875         switch (READ_ONCE(call->state)) {
876         case RXRPC_CALL_CLIENT_SEND_REQUEST:
877         case RXRPC_CALL_CLIENT_AWAIT_REPLY:
878         case RXRPC_CALL_SERVER_SEND_REPLY:
879         case RXRPC_CALL_SERVER_AWAIT_ACK:
880                 break;
881         default:
882                 return;
883         }
884
885         /* Discard any out-of-order or duplicate ACKs. */
886         if (before_eq(sp->hdr.serial, call->acks_latest)) {
887                 _debug("discard ACK %d <= %d",
888                        sp->hdr.serial, call->acks_latest);
889                 return;
890         }
891         call->acks_latest_ts = skb->tstamp;
892         call->acks_latest = sp->hdr.serial;
893
894         if (before(hard_ack, call->tx_hard_ack) ||
895             after(hard_ack, call->tx_top))
896                 return rxrpc_proto_abort("AKW", call, 0);
897         if (nr_acks > call->tx_top - hard_ack)
898                 return rxrpc_proto_abort("AKN", call, 0);
899
900         if (after(hard_ack, call->tx_hard_ack))
901                 rxrpc_rotate_tx_window(call, hard_ack, &summary);
902
903         if (nr_acks > 0) {
904                 if (skb_copy_bits(skb, offset, buf.acks, nr_acks) < 0)
905                         return rxrpc_proto_abort("XSA", call, 0);
906                 rxrpc_input_soft_acks(call, buf.acks, first_soft_ack, nr_acks,
907                                       &summary);
908         }
909
910         if (test_bit(RXRPC_CALL_TX_LAST, &call->flags)) {
911                 rxrpc_end_tx_phase(call, false, "ETA");
912                 return;
913         }
914
915         if (call->rxtx_annotations[call->tx_top & RXRPC_RXTX_BUFF_MASK] &
916             RXRPC_TX_ANNO_LAST &&
917             summary.nr_acks == call->tx_top - hard_ack &&
918             rxrpc_is_client_call(call))
919                 rxrpc_propose_ACK(call, RXRPC_ACK_PING, skew, sp->hdr.serial,
920                                   false, true,
921                                   rxrpc_propose_ack_ping_for_lost_reply);
922
923         return rxrpc_congestion_management(call, skb, &summary, acked_serial);
924 }
925
926 /*
927  * Process an ACKALL packet.
928  */
929 static void rxrpc_input_ackall(struct rxrpc_call *call, struct sk_buff *skb)
930 {
931         struct rxrpc_ack_summary summary = { 0 };
932         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
933
934         _proto("Rx ACKALL %%%u", sp->hdr.serial);
935
936         rxrpc_rotate_tx_window(call, call->tx_top, &summary);
937         if (test_bit(RXRPC_CALL_TX_LAST, &call->flags))
938                 rxrpc_end_tx_phase(call, false, "ETL");
939 }
940
941 /*
942  * Process an ABORT packet directed at a call.
943  */
944 static void rxrpc_input_abort(struct rxrpc_call *call, struct sk_buff *skb)
945 {
946         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
947         __be32 wtmp;
948         u32 abort_code = RX_CALL_DEAD;
949
950         _enter("");
951
952         if (skb->len >= 4 &&
953             skb_copy_bits(skb, sizeof(struct rxrpc_wire_header),
954                           &wtmp, sizeof(wtmp)) >= 0)
955                 abort_code = ntohl(wtmp);
956
957         trace_rxrpc_rx_abort(call, sp->hdr.serial, abort_code);
958
959         _proto("Rx ABORT %%%u { %x }", sp->hdr.serial, abort_code);
960
961         if (rxrpc_set_call_completion(call, RXRPC_CALL_REMOTELY_ABORTED,
962                                       abort_code, -ECONNABORTED))
963                 rxrpc_notify_socket(call);
964 }
965
966 /*
967  * Process an incoming call packet.
968  */
969 static void rxrpc_input_call_packet(struct rxrpc_call *call,
970                                     struct sk_buff *skb, u16 skew)
971 {
972         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
973         unsigned long timo;
974
975         _enter("%p,%p", call, skb);
976
977         timo = READ_ONCE(call->next_rx_timo);
978         if (timo) {
979                 unsigned long now = jiffies, expect_rx_by;
980
981                 expect_rx_by = now + timo;
982                 WRITE_ONCE(call->expect_rx_by, expect_rx_by);
983                 rxrpc_reduce_call_timer(call, expect_rx_by, now,
984                                         rxrpc_timer_set_for_normal);
985         }
986
987         switch (sp->hdr.type) {
988         case RXRPC_PACKET_TYPE_DATA:
989                 rxrpc_input_data(call, skb, skew);
990                 break;
991
992         case RXRPC_PACKET_TYPE_ACK:
993                 rxrpc_input_ack(call, skb, skew);
994                 break;
995
996         case RXRPC_PACKET_TYPE_BUSY:
997                 _proto("Rx BUSY %%%u", sp->hdr.serial);
998
999                 /* Just ignore BUSY packets from the server; the retry and
1000                  * lifespan timers will take care of business.  BUSY packets
1001                  * from the client don't make sense.
1002                  */
1003                 break;
1004
1005         case RXRPC_PACKET_TYPE_ABORT:
1006                 rxrpc_input_abort(call, skb);
1007                 break;
1008
1009         case RXRPC_PACKET_TYPE_ACKALL:
1010                 rxrpc_input_ackall(call, skb);
1011                 break;
1012
1013         default:
1014                 break;
1015         }
1016
1017         _leave("");
1018 }
1019
1020 /*
1021  * Handle a new call on a channel implicitly completing the preceding call on
1022  * that channel.
1023  *
1024  * TODO: If callNumber > call_id + 1, renegotiate security.
1025  */
1026 static void rxrpc_input_implicit_end_call(struct rxrpc_connection *conn,
1027                                           struct rxrpc_call *call)
1028 {
1029         switch (READ_ONCE(call->state)) {
1030         case RXRPC_CALL_SERVER_AWAIT_ACK:
1031                 rxrpc_call_completed(call);
1032                 break;
1033         case RXRPC_CALL_COMPLETE:
1034                 break;
1035         default:
1036                 if (rxrpc_abort_call("IMP", call, 0, RX_CALL_DEAD, -ESHUTDOWN)) {
1037                         set_bit(RXRPC_CALL_EV_ABORT, &call->events);
1038                         rxrpc_queue_call(call);
1039                 }
1040                 break;
1041         }
1042
1043         trace_rxrpc_improper_term(call);
1044         __rxrpc_disconnect_call(conn, call);
1045         rxrpc_notify_socket(call);
1046 }
1047
1048 /*
1049  * post connection-level events to the connection
1050  * - this includes challenges, responses, some aborts and call terminal packet
1051  *   retransmission.
1052  */
1053 static void rxrpc_post_packet_to_conn(struct rxrpc_connection *conn,
1054                                       struct sk_buff *skb)
1055 {
1056         _enter("%p,%p", conn, skb);
1057
1058         skb_queue_tail(&conn->rx_queue, skb);
1059         rxrpc_queue_conn(conn);
1060 }
1061
1062 /*
1063  * post endpoint-level events to the local endpoint
1064  * - this includes debug and version messages
1065  */
1066 static void rxrpc_post_packet_to_local(struct rxrpc_local *local,
1067                                        struct sk_buff *skb)
1068 {
1069         _enter("%p,%p", local, skb);
1070
1071         skb_queue_tail(&local->event_queue, skb);
1072         rxrpc_queue_local(local);
1073 }
1074
1075 /*
1076  * put a packet up for transport-level abort
1077  */
1078 static void rxrpc_reject_packet(struct rxrpc_local *local, struct sk_buff *skb)
1079 {
1080         CHECK_SLAB_OKAY(&local->usage);
1081
1082         skb_queue_tail(&local->reject_queue, skb);
1083         rxrpc_queue_local(local);
1084 }
1085
1086 /*
1087  * Extract the wire header from a packet and translate the byte order.
1088  */
1089 static noinline
1090 int rxrpc_extract_header(struct rxrpc_skb_priv *sp, struct sk_buff *skb)
1091 {
1092         struct rxrpc_wire_header whdr;
1093
1094         /* dig out the RxRPC connection details */
1095         if (skb_copy_bits(skb, 0, &whdr, sizeof(whdr)) < 0) {
1096                 trace_rxrpc_rx_eproto(NULL, sp->hdr.serial,
1097                                       tracepoint_string("bad_hdr"));
1098                 return -EBADMSG;
1099         }
1100
1101         memset(sp, 0, sizeof(*sp));
1102         sp->hdr.epoch           = ntohl(whdr.epoch);
1103         sp->hdr.cid             = ntohl(whdr.cid);
1104         sp->hdr.callNumber      = ntohl(whdr.callNumber);
1105         sp->hdr.seq             = ntohl(whdr.seq);
1106         sp->hdr.serial          = ntohl(whdr.serial);
1107         sp->hdr.flags           = whdr.flags;
1108         sp->hdr.type            = whdr.type;
1109         sp->hdr.userStatus      = whdr.userStatus;
1110         sp->hdr.securityIndex   = whdr.securityIndex;
1111         sp->hdr._rsvd           = ntohs(whdr._rsvd);
1112         sp->hdr.serviceId       = ntohs(whdr.serviceId);
1113         return 0;
1114 }
1115
1116 /*
1117  * handle data received on the local endpoint
1118  * - may be called in interrupt context
1119  *
1120  * The socket is locked by the caller and this prevents the socket from being
1121  * shut down and the local endpoint from going away, thus sk_user_data will not
1122  * be cleared until this function returns.
1123  */
1124 void rxrpc_data_ready(struct sock *udp_sk)
1125 {
1126         struct rxrpc_connection *conn;
1127         struct rxrpc_channel *chan;
1128         struct rxrpc_call *call = NULL;
1129         struct rxrpc_skb_priv *sp;
1130         struct rxrpc_local *local = udp_sk->sk_user_data;
1131         struct rxrpc_peer *peer = NULL;
1132         struct rxrpc_sock *rx = NULL;
1133         struct sk_buff *skb;
1134         unsigned int channel;
1135         int ret, skew = 0;
1136
1137         _enter("%p", udp_sk);
1138
1139         ASSERT(!irqs_disabled());
1140
1141         skb = skb_recv_udp(udp_sk, 0, 1, &ret);
1142         if (!skb) {
1143                 if (ret == -EAGAIN)
1144                         return;
1145                 _debug("UDP socket error %d", ret);
1146                 return;
1147         }
1148
1149         if (skb->tstamp == 0)
1150                 skb->tstamp = ktime_get_real();
1151
1152         rxrpc_new_skb(skb, rxrpc_skb_rx_received);
1153
1154         _net("recv skb %p", skb);
1155
1156         /* we'll probably need to checksum it (didn't call sock_recvmsg) */
1157         if (skb_checksum_complete(skb)) {
1158                 rxrpc_free_skb(skb, rxrpc_skb_rx_freed);
1159                 __UDP_INC_STATS(&init_net, UDP_MIB_INERRORS, 0);
1160                 _leave(" [CSUM failed]");
1161                 return;
1162         }
1163
1164         __UDP_INC_STATS(&init_net, UDP_MIB_INDATAGRAMS, 0);
1165
1166         /* The UDP protocol already released all skb resources;
1167          * we are free to add our own data there.
1168          */
1169         sp = rxrpc_skb(skb);
1170
1171         /* dig out the RxRPC connection details */
1172         if (rxrpc_extract_header(sp, skb) < 0)
1173                 goto bad_message;
1174
1175         if (IS_ENABLED(CONFIG_AF_RXRPC_INJECT_LOSS)) {
1176                 static int lose;
1177                 if ((lose++ & 7) == 7) {
1178                         trace_rxrpc_rx_lose(sp);
1179                         rxrpc_free_skb(skb, rxrpc_skb_rx_lost);
1180                         return;
1181                 }
1182         }
1183
1184         trace_rxrpc_rx_packet(sp);
1185
1186         switch (sp->hdr.type) {
1187         case RXRPC_PACKET_TYPE_VERSION:
1188                 if (rxrpc_to_client(sp))
1189                         goto discard;
1190                 rxrpc_post_packet_to_local(local, skb);
1191                 goto out;
1192
1193         case RXRPC_PACKET_TYPE_BUSY:
1194                 if (rxrpc_to_server(sp))
1195                         goto discard;
1196                 /* Fall through */
1197         case RXRPC_PACKET_TYPE_ACK:
1198         case RXRPC_PACKET_TYPE_ACKALL:
1199                 if (sp->hdr.callNumber == 0)
1200                         goto bad_message;
1201                 /* Fall through */
1202         case RXRPC_PACKET_TYPE_ABORT:
1203                 break;
1204
1205         case RXRPC_PACKET_TYPE_DATA:
1206                 if (sp->hdr.callNumber == 0 ||
1207                     sp->hdr.seq == 0)
1208                         goto bad_message;
1209                 if (sp->hdr.flags & RXRPC_JUMBO_PACKET &&
1210                     !rxrpc_validate_jumbo(skb))
1211                         goto bad_message;
1212                 break;
1213
1214         case RXRPC_PACKET_TYPE_CHALLENGE:
1215                 if (rxrpc_to_server(sp))
1216                         goto discard;
1217                 break;
1218         case RXRPC_PACKET_TYPE_RESPONSE:
1219                 if (rxrpc_to_client(sp))
1220                         goto discard;
1221                 break;
1222
1223                 /* Packet types 9-11 should just be ignored. */
1224         case RXRPC_PACKET_TYPE_PARAMS:
1225         case RXRPC_PACKET_TYPE_10:
1226         case RXRPC_PACKET_TYPE_11:
1227                 goto discard;
1228
1229         default:
1230                 _proto("Rx Bad Packet Type %u", sp->hdr.type);
1231                 goto bad_message;
1232         }
1233
1234         if (sp->hdr.serviceId == 0)
1235                 goto bad_message;
1236
1237         rcu_read_lock();
1238
1239         if (rxrpc_to_server(sp)) {
1240                 /* Weed out packets to services we're not offering.  Packets
1241                  * that would begin a call are explicitly rejected and the rest
1242                  * are just discarded.
1243                  */
1244                 rx = rcu_dereference(local->service);
1245                 if (!rx || (sp->hdr.serviceId != rx->srx.srx_service &&
1246                             sp->hdr.serviceId != rx->second_service)) {
1247                         if (sp->hdr.type == RXRPC_PACKET_TYPE_DATA &&
1248                             sp->hdr.seq == 1)
1249                                 goto unsupported_service;
1250                         goto discard_unlock;
1251                 }
1252         }
1253
1254         conn = rxrpc_find_connection_rcu(local, skb, &peer);
1255         if (conn) {
1256                 if (sp->hdr.securityIndex != conn->security_ix)
1257                         goto wrong_security;
1258
1259                 if (sp->hdr.serviceId != conn->service_id) {
1260                         if (!test_bit(RXRPC_CONN_PROBING_FOR_UPGRADE, &conn->flags) ||
1261                             conn->service_id != conn->params.service_id)
1262                                 goto reupgrade;
1263                         conn->service_id = sp->hdr.serviceId;
1264                 }
1265
1266                 if (sp->hdr.callNumber == 0) {
1267                         /* Connection-level packet */
1268                         _debug("CONN %p {%d}", conn, conn->debug_id);
1269                         rxrpc_post_packet_to_conn(conn, skb);
1270                         goto out_unlock;
1271                 }
1272
1273                 /* Note the serial number skew here */
1274                 skew = (int)sp->hdr.serial - (int)conn->hi_serial;
1275                 if (skew >= 0) {
1276                         if (skew > 0)
1277                                 conn->hi_serial = sp->hdr.serial;
1278                 } else {
1279                         skew = -skew;
1280                         skew = min(skew, 65535);
1281                 }
1282
1283                 /* Call-bound packets are routed by connection channel. */
1284                 channel = sp->hdr.cid & RXRPC_CHANNELMASK;
1285                 chan = &conn->channels[channel];
1286
1287                 /* Ignore really old calls */
1288                 if (sp->hdr.callNumber < chan->last_call)
1289                         goto discard_unlock;
1290
1291                 if (sp->hdr.callNumber == chan->last_call) {
1292                         if (chan->call ||
1293                             sp->hdr.type == RXRPC_PACKET_TYPE_ABORT)
1294                                 goto discard_unlock;
1295
1296                         /* For the previous service call, if completed
1297                          * successfully, we discard all further packets.
1298                          */
1299                         if (rxrpc_conn_is_service(conn) &&
1300                             chan->last_type == RXRPC_PACKET_TYPE_ACK)
1301                                 goto discard_unlock;
1302
1303                         /* But otherwise we need to retransmit the final packet
1304                          * from data cached in the connection record.
1305                          */
1306                         if (sp->hdr.type == RXRPC_PACKET_TYPE_DATA)
1307                                 trace_rxrpc_rx_data(chan->call_debug_id,
1308                                                     sp->hdr.seq,
1309                                                     sp->hdr.serial,
1310                                                     sp->hdr.flags, 0);
1311                         rxrpc_post_packet_to_conn(conn, skb);
1312                         goto out_unlock;
1313                 }
1314
1315                 call = rcu_dereference(chan->call);
1316
1317                 if (sp->hdr.callNumber > chan->call_id) {
1318                         if (rxrpc_to_client(sp)) {
1319                                 rcu_read_unlock();
1320                                 goto reject_packet;
1321                         }
1322                         if (call)
1323                                 rxrpc_input_implicit_end_call(conn, call);
1324                         call = NULL;
1325                 }
1326
1327                 if (call) {
1328                         if (sp->hdr.serviceId != call->service_id)
1329                                 call->service_id = sp->hdr.serviceId;
1330                         if ((int)sp->hdr.serial - (int)call->rx_serial > 0)
1331                                 call->rx_serial = sp->hdr.serial;
1332                         if (!test_bit(RXRPC_CALL_RX_HEARD, &call->flags))
1333                                 set_bit(RXRPC_CALL_RX_HEARD, &call->flags);
1334                 }
1335         }
1336
1337         if (!call || atomic_read(&call->usage) == 0) {
1338                 if (rxrpc_to_client(sp) ||
1339                     sp->hdr.type != RXRPC_PACKET_TYPE_DATA)
1340                         goto bad_message_unlock;
1341                 if (sp->hdr.seq != 1)
1342                         goto discard_unlock;
1343                 call = rxrpc_new_incoming_call(local, rx, peer, conn, skb);
1344                 if (!call) {
1345                         rcu_read_unlock();
1346                         goto reject_packet;
1347                 }
1348                 rxrpc_send_ping(call, skb, skew);
1349                 mutex_unlock(&call->user_mutex);
1350         }
1351
1352         rxrpc_input_call_packet(call, skb, skew);
1353         goto discard_unlock;
1354
1355 discard_unlock:
1356         rcu_read_unlock();
1357 discard:
1358         rxrpc_free_skb(skb, rxrpc_skb_rx_freed);
1359 out:
1360         trace_rxrpc_rx_done(0, 0);
1361         return;
1362
1363 out_unlock:
1364         rcu_read_unlock();
1365         goto out;
1366
1367 wrong_security:
1368         rcu_read_unlock();
1369         trace_rxrpc_abort(0, "SEC", sp->hdr.cid, sp->hdr.callNumber, sp->hdr.seq,
1370                           RXKADINCONSISTENCY, EBADMSG);
1371         skb->priority = RXKADINCONSISTENCY;
1372         goto post_abort;
1373
1374 unsupported_service:
1375         rcu_read_unlock();
1376         trace_rxrpc_abort(0, "INV", sp->hdr.cid, sp->hdr.callNumber, sp->hdr.seq,
1377                           RX_INVALID_OPERATION, EOPNOTSUPP);
1378         skb->priority = RX_INVALID_OPERATION;
1379         goto post_abort;
1380
1381 reupgrade:
1382         rcu_read_unlock();
1383         trace_rxrpc_abort(0, "UPG", sp->hdr.cid, sp->hdr.callNumber, sp->hdr.seq,
1384                           RX_PROTOCOL_ERROR, EBADMSG);
1385         goto protocol_error;
1386
1387 bad_message_unlock:
1388         rcu_read_unlock();
1389 bad_message:
1390         trace_rxrpc_abort(0, "BAD", sp->hdr.cid, sp->hdr.callNumber, sp->hdr.seq,
1391                           RX_PROTOCOL_ERROR, EBADMSG);
1392 protocol_error:
1393         skb->priority = RX_PROTOCOL_ERROR;
1394 post_abort:
1395         skb->mark = RXRPC_SKB_MARK_REJECT_ABORT;
1396 reject_packet:
1397         trace_rxrpc_rx_done(skb->mark, skb->priority);
1398         rxrpc_reject_packet(local, skb);
1399         _leave(" [badmsg]");
1400 }