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1/* RxRPC packet reception
2 *
3 * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
4 * Written by David Howells (dhowells@redhat.com)
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
10 */
11
12#include <linux/module.h>
13#include <linux/net.h>
14#include <linux/skbuff.h>
15#include <linux/errqueue.h>
16#include <linux/udp.h>
17#include <linux/in.h>
18#include <linux/in6.h>
19#include <linux/icmp.h>
20#include <linux/gfp.h>
21#include <net/sock.h>
22#include <net/af_rxrpc.h>
23#include <net/ip.h>
24#include <net/udp.h>
25#include <net/net_namespace.h>
26#include "ar-internal.h"
27
28unsigned long rxrpc_ack_timeout = 1;
29
30const char *rxrpc_pkts[] = {
31 "?00",
32 "DATA", "ACK", "BUSY", "ABORT", "ACKALL", "CHALL", "RESP", "DEBUG",
33 "?09", "?10", "?11", "?12", "?13", "?14", "?15"
34};
35
36/*
37 * queue a packet for recvmsg to pass to userspace
38 * - the caller must hold a lock on call->lock
39 * - must not be called with interrupts disabled (sk_filter() disables BH's)
40 * - eats the packet whether successful or not
41 * - there must be just one reference to the packet, which the caller passes to
42 * this function
43 */
44int rxrpc_queue_rcv_skb(struct rxrpc_call *call, struct sk_buff *skb,
45 bool force, bool terminal)
46{
47 struct rxrpc_skb_priv *sp;
48 struct rxrpc_sock *rx = call->socket;
49 struct sock *sk;
50 int skb_len, ret;
51
52 _enter(",,%d,%d", force, terminal);
53
54 ASSERT(!irqs_disabled());
55
56 sp = rxrpc_skb(skb);
57 ASSERTCMP(sp->call, ==, call);
58
59 /* if we've already posted the terminal message for a call, then we
60 * don't post any more */
61 if (test_bit(RXRPC_CALL_TERMINAL_MSG, &call->flags)) {
62 _debug("already terminated");
63 ASSERTCMP(call->state, >=, RXRPC_CALL_COMPLETE);
64 skb->destructor = NULL;
65 sp->call = NULL;
66 rxrpc_put_call(call);
67 rxrpc_free_skb(skb);
68 return 0;
69 }
70
71 sk = &rx->sk;
72
73 if (!force) {
74 /* cast skb->rcvbuf to unsigned... It's pointless, but
75 * reduces number of warnings when compiling with -W
76 * --ANK */
77// ret = -ENOBUFS;
78// if (atomic_read(&sk->sk_rmem_alloc) + skb->truesize >=
79// (unsigned) sk->sk_rcvbuf)
80// goto out;
81
82 ret = sk_filter(sk, skb);
83 if (ret < 0)
84 goto out;
85 }
86
87 spin_lock_bh(&sk->sk_receive_queue.lock);
88 if (!test_bit(RXRPC_CALL_TERMINAL_MSG, &call->flags) &&
89 !test_bit(RXRPC_CALL_RELEASED, &call->flags) &&
90 call->socket->sk.sk_state != RXRPC_CLOSE) {
91 skb->destructor = rxrpc_packet_destructor;
92 skb->dev = NULL;
93 skb->sk = sk;
94 atomic_add(skb->truesize, &sk->sk_rmem_alloc);
95
96 if (terminal) {
97 _debug("<<<< TERMINAL MESSAGE >>>>");
98 set_bit(RXRPC_CALL_TERMINAL_MSG, &call->flags);
99 }
100
101 /* allow interception by a kernel service */
102 if (rx->interceptor) {
103 rx->interceptor(sk, call->user_call_ID, skb);
104 spin_unlock_bh(&sk->sk_receive_queue.lock);
105 } else {
106
107 /* Cache the SKB length before we tack it onto the
108 * receive queue. Once it is added it no longer
109 * belongs to us and may be freed by other threads of
110 * control pulling packets from the queue */
111 skb_len = skb->len;
112
113 _net("post skb %p", skb);
114 __skb_queue_tail(&sk->sk_receive_queue, skb);
115 spin_unlock_bh(&sk->sk_receive_queue.lock);
116
117 if (!sock_flag(sk, SOCK_DEAD))
118 sk->sk_data_ready(sk, skb_len);
119 }
120 skb = NULL;
121 } else {
122 spin_unlock_bh(&sk->sk_receive_queue.lock);
123 }
124 ret = 0;
125
126out:
127 /* release the socket buffer */
128 if (skb) {
129 skb->destructor = NULL;
130 sp->call = NULL;
131 rxrpc_put_call(call);
132 rxrpc_free_skb(skb);
133 }
134
135 _leave(" = %d", ret);
136 return ret;
137}
138
139/*
140 * process a DATA packet, posting the packet to the appropriate queue
141 * - eats the packet if successful
142 */
143static int rxrpc_fast_process_data(struct rxrpc_call *call,
144 struct sk_buff *skb, u32 seq)
145{
146 struct rxrpc_skb_priv *sp;
147 bool terminal;
148 int ret, ackbit, ack;
149
150 _enter("{%u,%u},,{%u}", call->rx_data_post, call->rx_first_oos, seq);
151
152 sp = rxrpc_skb(skb);
153 ASSERTCMP(sp->call, ==, NULL);
154
155 spin_lock(&call->lock);
156
157 if (call->state > RXRPC_CALL_COMPLETE)
158 goto discard;
159
160 ASSERTCMP(call->rx_data_expect, >=, call->rx_data_post);
161 ASSERTCMP(call->rx_data_post, >=, call->rx_data_recv);
162 ASSERTCMP(call->rx_data_recv, >=, call->rx_data_eaten);
163
164 if (seq < call->rx_data_post) {
165 _debug("dup #%u [-%u]", seq, call->rx_data_post);
166 ack = RXRPC_ACK_DUPLICATE;
167 ret = -ENOBUFS;
168 goto discard_and_ack;
169 }
170
171 /* we may already have the packet in the out of sequence queue */
172 ackbit = seq - (call->rx_data_eaten + 1);
173 ASSERTCMP(ackbit, >=, 0);
174 if (__test_and_set_bit(ackbit, call->ackr_window)) {
175 _debug("dup oos #%u [%u,%u]",
176 seq, call->rx_data_eaten, call->rx_data_post);
177 ack = RXRPC_ACK_DUPLICATE;
178 goto discard_and_ack;
179 }
180
181 if (seq >= call->ackr_win_top) {
182 _debug("exceed #%u [%u]", seq, call->ackr_win_top);
183 __clear_bit(ackbit, call->ackr_window);
184 ack = RXRPC_ACK_EXCEEDS_WINDOW;
185 goto discard_and_ack;
186 }
187
188 if (seq == call->rx_data_expect) {
189 clear_bit(RXRPC_CALL_EXPECT_OOS, &call->flags);
190 call->rx_data_expect++;
191 } else if (seq > call->rx_data_expect) {
192 _debug("oos #%u [%u]", seq, call->rx_data_expect);
193 call->rx_data_expect = seq + 1;
194 if (test_and_set_bit(RXRPC_CALL_EXPECT_OOS, &call->flags)) {
195 ack = RXRPC_ACK_OUT_OF_SEQUENCE;
196 goto enqueue_and_ack;
197 }
198 goto enqueue_packet;
199 }
200
201 if (seq != call->rx_data_post) {
202 _debug("ahead #%u [%u]", seq, call->rx_data_post);
203 goto enqueue_packet;
204 }
205
206 if (test_bit(RXRPC_CALL_RCVD_LAST, &call->flags))
207 goto protocol_error;
208
209 /* if the packet need security things doing to it, then it goes down
210 * the slow path */
211 if (call->conn->security)
212 goto enqueue_packet;
213
214 sp->call = call;
215 rxrpc_get_call(call);
216 terminal = ((sp->hdr.flags & RXRPC_LAST_PACKET) &&
217 !(sp->hdr.flags & RXRPC_CLIENT_INITIATED));
218 ret = rxrpc_queue_rcv_skb(call, skb, false, terminal);
219 if (ret < 0) {
220 if (ret == -ENOMEM || ret == -ENOBUFS) {
221 __clear_bit(ackbit, call->ackr_window);
222 ack = RXRPC_ACK_NOSPACE;
223 goto discard_and_ack;
224 }
225 goto out;
226 }
227
228 skb = NULL;
229
230 _debug("post #%u", seq);
231 ASSERTCMP(call->rx_data_post, ==, seq);
232 call->rx_data_post++;
233
234 if (sp->hdr.flags & RXRPC_LAST_PACKET)
235 set_bit(RXRPC_CALL_RCVD_LAST, &call->flags);
236
237 /* if we've reached an out of sequence packet then we need to drain
238 * that queue into the socket Rx queue now */
239 if (call->rx_data_post == call->rx_first_oos) {
240 _debug("drain rx oos now");
241 read_lock(&call->state_lock);
242 if (call->state < RXRPC_CALL_COMPLETE &&
243 !test_and_set_bit(RXRPC_CALL_DRAIN_RX_OOS, &call->events))
244 rxrpc_queue_call(call);
245 read_unlock(&call->state_lock);
246 }
247
248 spin_unlock(&call->lock);
249 atomic_inc(&call->ackr_not_idle);
250 rxrpc_propose_ACK(call, RXRPC_ACK_DELAY, sp->hdr.serial, false);
251 _leave(" = 0 [posted]");
252 return 0;
253
254protocol_error:
255 ret = -EBADMSG;
256out:
257 spin_unlock(&call->lock);
258 _leave(" = %d", ret);
259 return ret;
260
261discard_and_ack:
262 _debug("discard and ACK packet %p", skb);
263 __rxrpc_propose_ACK(call, ack, sp->hdr.serial, true);
264discard:
265 spin_unlock(&call->lock);
266 rxrpc_free_skb(skb);
267 _leave(" = 0 [discarded]");
268 return 0;
269
270enqueue_and_ack:
271 __rxrpc_propose_ACK(call, ack, sp->hdr.serial, true);
272enqueue_packet:
273 _net("defer skb %p", skb);
274 spin_unlock(&call->lock);
275 skb_queue_tail(&call->rx_queue, skb);
276 atomic_inc(&call->ackr_not_idle);
277 read_lock(&call->state_lock);
278 if (call->state < RXRPC_CALL_DEAD)
279 rxrpc_queue_call(call);
280 read_unlock(&call->state_lock);
281 _leave(" = 0 [queued]");
282 return 0;
283}
284
285/*
286 * assume an implicit ACKALL of the transmission phase of a client socket upon
287 * reception of the first reply packet
288 */
289static void rxrpc_assume_implicit_ackall(struct rxrpc_call *call, u32 serial)
290{
291 write_lock_bh(&call->state_lock);
292
293 switch (call->state) {
294 case RXRPC_CALL_CLIENT_AWAIT_REPLY:
295 call->state = RXRPC_CALL_CLIENT_RECV_REPLY;
296 call->acks_latest = serial;
297
298 _debug("implicit ACKALL %%%u", call->acks_latest);
299 set_bit(RXRPC_CALL_RCVD_ACKALL, &call->events);
300 write_unlock_bh(&call->state_lock);
301
302 if (try_to_del_timer_sync(&call->resend_timer) >= 0) {
303 clear_bit(RXRPC_CALL_RESEND_TIMER, &call->events);
304 clear_bit(RXRPC_CALL_RESEND, &call->events);
305 clear_bit(RXRPC_CALL_RUN_RTIMER, &call->flags);
306 }
307 break;
308
309 default:
310 write_unlock_bh(&call->state_lock);
311 break;
312 }
313}
314
315/*
316 * post an incoming packet to the nominated call to deal with
317 * - must get rid of the sk_buff, either by freeing it or by queuing it
318 */
319void rxrpc_fast_process_packet(struct rxrpc_call *call, struct sk_buff *skb)
320{
321 struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
322 __be32 _abort_code;
323 u32 serial, hi_serial, seq, abort_code;
324
325 _enter("%p,%p", call, skb);
326
327 ASSERT(!irqs_disabled());
328
329#if 0 // INJECT RX ERROR
330 if (sp->hdr.type == RXRPC_PACKET_TYPE_DATA) {
331 static int skip = 0;
332 if (++skip == 3) {
333 printk("DROPPED 3RD PACKET!!!!!!!!!!!!!\n");
334 skip = 0;
335 goto free_packet;
336 }
337 }
338#endif
339
340 /* track the latest serial number on this connection for ACK packet
341 * information */
342 serial = ntohl(sp->hdr.serial);
343 hi_serial = atomic_read(&call->conn->hi_serial);
344 while (serial > hi_serial)
345 hi_serial = atomic_cmpxchg(&call->conn->hi_serial, hi_serial,
346 serial);
347
348 /* request ACK generation for any ACK or DATA packet that requests
349 * it */
350 if (sp->hdr.flags & RXRPC_REQUEST_ACK) {
351 _proto("ACK Requested on %%%u", serial);
352 rxrpc_propose_ACK(call, RXRPC_ACK_REQUESTED, sp->hdr.serial,
353 !(sp->hdr.flags & RXRPC_MORE_PACKETS));
354 }
355
356 switch (sp->hdr.type) {
357 case RXRPC_PACKET_TYPE_ABORT:
358 _debug("abort");
359
360 if (skb_copy_bits(skb, 0, &_abort_code,
361 sizeof(_abort_code)) < 0)
362 goto protocol_error;
363
364 abort_code = ntohl(_abort_code);
365 _proto("Rx ABORT %%%u { %x }", serial, abort_code);
366
367 write_lock_bh(&call->state_lock);
368 if (call->state < RXRPC_CALL_COMPLETE) {
369 call->state = RXRPC_CALL_REMOTELY_ABORTED;
370 call->abort_code = abort_code;
371 set_bit(RXRPC_CALL_RCVD_ABORT, &call->events);
372 rxrpc_queue_call(call);
373 }
374 goto free_packet_unlock;
375
376 case RXRPC_PACKET_TYPE_BUSY:
377 _proto("Rx BUSY %%%u", serial);
378
379 if (call->conn->out_clientflag)
380 goto protocol_error;
381
382 write_lock_bh(&call->state_lock);
383 switch (call->state) {
384 case RXRPC_CALL_CLIENT_SEND_REQUEST:
385 call->state = RXRPC_CALL_SERVER_BUSY;
386 set_bit(RXRPC_CALL_RCVD_BUSY, &call->events);
387 rxrpc_queue_call(call);
388 case RXRPC_CALL_SERVER_BUSY:
389 goto free_packet_unlock;
390 default:
391 goto protocol_error_locked;
392 }
393
394 default:
395 _proto("Rx %s %%%u", rxrpc_pkts[sp->hdr.type], serial);
396 goto protocol_error;
397
398 case RXRPC_PACKET_TYPE_DATA:
399 seq = ntohl(sp->hdr.seq);
400
401 _proto("Rx DATA %%%u { #%u }", serial, seq);
402
403 if (seq == 0)
404 goto protocol_error;
405
406 call->ackr_prev_seq = sp->hdr.seq;
407
408 /* received data implicitly ACKs all of the request packets we
409 * sent when we're acting as a client */
410 if (call->state == RXRPC_CALL_CLIENT_AWAIT_REPLY)
411 rxrpc_assume_implicit_ackall(call, serial);
412
413 switch (rxrpc_fast_process_data(call, skb, seq)) {
414 case 0:
415 skb = NULL;
416 goto done;
417
418 default:
419 BUG();
420
421 /* data packet received beyond the last packet */
422 case -EBADMSG:
423 goto protocol_error;
424 }
425
426 case RXRPC_PACKET_TYPE_ACKALL:
427 case RXRPC_PACKET_TYPE_ACK:
428 /* ACK processing is done in process context */
429 read_lock_bh(&call->state_lock);
430 if (call->state < RXRPC_CALL_DEAD) {
431 skb_queue_tail(&call->rx_queue, skb);
432 rxrpc_queue_call(call);
433 skb = NULL;
434 }
435 read_unlock_bh(&call->state_lock);
436 goto free_packet;
437 }
438
439protocol_error:
440 _debug("protocol error");
441 write_lock_bh(&call->state_lock);
442protocol_error_locked:
443 if (call->state <= RXRPC_CALL_COMPLETE) {
444 call->state = RXRPC_CALL_LOCALLY_ABORTED;
445 call->abort_code = RX_PROTOCOL_ERROR;
446 set_bit(RXRPC_CALL_ABORT, &call->events);
447 rxrpc_queue_call(call);
448 }
449free_packet_unlock:
450 write_unlock_bh(&call->state_lock);
451free_packet:
452 rxrpc_free_skb(skb);
453done:
454 _leave("");
455}
456
457/*
458 * split up a jumbo data packet
459 */
460static void rxrpc_process_jumbo_packet(struct rxrpc_call *call,
461 struct sk_buff *jumbo)
462{
463 struct rxrpc_jumbo_header jhdr;
464 struct rxrpc_skb_priv *sp;
465 struct sk_buff *part;
466
467 _enter(",{%u,%u}", jumbo->data_len, jumbo->len);
468
469 sp = rxrpc_skb(jumbo);
470
471 do {
472 sp->hdr.flags &= ~RXRPC_JUMBO_PACKET;
473
474 /* make a clone to represent the first subpacket in what's left
475 * of the jumbo packet */
476 part = skb_clone(jumbo, GFP_ATOMIC);
477 if (!part) {
478 /* simply ditch the tail in the event of ENOMEM */
479 pskb_trim(jumbo, RXRPC_JUMBO_DATALEN);
480 break;
481 }
482 rxrpc_new_skb(part);
483
484 pskb_trim(part, RXRPC_JUMBO_DATALEN);
485
486 if (!pskb_pull(jumbo, RXRPC_JUMBO_DATALEN))
487 goto protocol_error;
488
489 if (skb_copy_bits(jumbo, 0, &jhdr, sizeof(jhdr)) < 0)
490 goto protocol_error;
491 if (!pskb_pull(jumbo, sizeof(jhdr)))
492 BUG();
493
494 sp->hdr.seq = htonl(ntohl(sp->hdr.seq) + 1);
495 sp->hdr.serial = htonl(ntohl(sp->hdr.serial) + 1);
496 sp->hdr.flags = jhdr.flags;
497 sp->hdr._rsvd = jhdr._rsvd;
498
499 _proto("Rx DATA Jumbo %%%u", ntohl(sp->hdr.serial) - 1);
500
501 rxrpc_fast_process_packet(call, part);
502 part = NULL;
503
504 } while (sp->hdr.flags & RXRPC_JUMBO_PACKET);
505
506 rxrpc_fast_process_packet(call, jumbo);
507 _leave("");
508 return;
509
510protocol_error:
511 _debug("protocol error");
512 rxrpc_free_skb(part);
513 rxrpc_free_skb(jumbo);
514 write_lock_bh(&call->state_lock);
515 if (call->state <= RXRPC_CALL_COMPLETE) {
516 call->state = RXRPC_CALL_LOCALLY_ABORTED;
517 call->abort_code = RX_PROTOCOL_ERROR;
518 set_bit(RXRPC_CALL_ABORT, &call->events);
519 rxrpc_queue_call(call);
520 }
521 write_unlock_bh(&call->state_lock);
522 _leave("");
523}
524
525/*
526 * post an incoming packet to the appropriate call/socket to deal with
527 * - must get rid of the sk_buff, either by freeing it or by queuing it
528 */
529static void rxrpc_post_packet_to_call(struct rxrpc_connection *conn,
530 struct sk_buff *skb)
531{
532 struct rxrpc_skb_priv *sp;
533 struct rxrpc_call *call;
534 struct rb_node *p;
535 __be32 call_id;
536
537 _enter("%p,%p", conn, skb);
538
539 read_lock_bh(&conn->lock);
540
541 sp = rxrpc_skb(skb);
542
543 /* look at extant calls by channel number first */
544 call = conn->channels[ntohl(sp->hdr.cid) & RXRPC_CHANNELMASK];
545 if (!call || call->call_id != sp->hdr.callNumber)
546 goto call_not_extant;
547
548 _debug("extant call [%d]", call->state);
549 ASSERTCMP(call->conn, ==, conn);
550
551 read_lock(&call->state_lock);
552 switch (call->state) {
553 case RXRPC_CALL_LOCALLY_ABORTED:
554 if (!test_and_set_bit(RXRPC_CALL_ABORT, &call->events))
555 rxrpc_queue_call(call);
556 case RXRPC_CALL_REMOTELY_ABORTED:
557 case RXRPC_CALL_NETWORK_ERROR:
558 case RXRPC_CALL_DEAD:
559 goto free_unlock;
560 default:
561 break;
562 }
563
564 read_unlock(&call->state_lock);
565 rxrpc_get_call(call);
566 read_unlock_bh(&conn->lock);
567
568 if (sp->hdr.type == RXRPC_PACKET_TYPE_DATA &&
569 sp->hdr.flags & RXRPC_JUMBO_PACKET)
570 rxrpc_process_jumbo_packet(call, skb);
571 else
572 rxrpc_fast_process_packet(call, skb);
573
574 rxrpc_put_call(call);
575 goto done;
576
577call_not_extant:
578 /* search the completed calls in case what we're dealing with is
579 * there */
580 _debug("call not extant");
581
582 call_id = sp->hdr.callNumber;
583 p = conn->calls.rb_node;
584 while (p) {
585 call = rb_entry(p, struct rxrpc_call, conn_node);
586
587 if (call_id < call->call_id)
588 p = p->rb_left;
589 else if (call_id > call->call_id)
590 p = p->rb_right;
591 else
592 goto found_completed_call;
593 }
594
595dead_call:
596 /* it's a either a really old call that we no longer remember or its a
597 * new incoming call */
598 read_unlock_bh(&conn->lock);
599
600 if (sp->hdr.flags & RXRPC_CLIENT_INITIATED &&
601 sp->hdr.seq == cpu_to_be32(1)) {
602 _debug("incoming call");
603 skb_queue_tail(&conn->trans->local->accept_queue, skb);
604 rxrpc_queue_work(&conn->trans->local->acceptor);
605 goto done;
606 }
607
608 _debug("dead call");
609 skb->priority = RX_CALL_DEAD;
610 rxrpc_reject_packet(conn->trans->local, skb);
611 goto done;
612
613 /* resend last packet of a completed call
614 * - client calls may have been aborted or ACK'd
615 * - server calls may have been aborted
616 */
617found_completed_call:
618 _debug("completed call");
619
620 if (atomic_read(&call->usage) == 0)
621 goto dead_call;
622
623 /* synchronise any state changes */
624 read_lock(&call->state_lock);
625 ASSERTIFCMP(call->state != RXRPC_CALL_CLIENT_FINAL_ACK,
626 call->state, >=, RXRPC_CALL_COMPLETE);
627
628 if (call->state == RXRPC_CALL_LOCALLY_ABORTED ||
629 call->state == RXRPC_CALL_REMOTELY_ABORTED ||
630 call->state == RXRPC_CALL_DEAD) {
631 read_unlock(&call->state_lock);
632 goto dead_call;
633 }
634
635 if (call->conn->in_clientflag) {
636 read_unlock(&call->state_lock);
637 goto dead_call; /* complete server call */
638 }
639
640 _debug("final ack again");
641 rxrpc_get_call(call);
642 set_bit(RXRPC_CALL_ACK_FINAL, &call->events);
643 rxrpc_queue_call(call);
644
645free_unlock:
646 read_unlock(&call->state_lock);
647 read_unlock_bh(&conn->lock);
648 rxrpc_free_skb(skb);
649done:
650 _leave("");
651}
652
653/*
654 * post connection-level events to the connection
655 * - this includes challenges, responses and some aborts
656 */
657static void rxrpc_post_packet_to_conn(struct rxrpc_connection *conn,
658 struct sk_buff *skb)
659{
660 _enter("%p,%p", conn, skb);
661
662 atomic_inc(&conn->usage);
663 skb_queue_tail(&conn->rx_queue, skb);
664 rxrpc_queue_conn(conn);
665}
666
667/*
668 * handle data received on the local endpoint
669 * - may be called in interrupt context
670 */
671void rxrpc_data_ready(struct sock *sk, int count)
672{
673 struct rxrpc_connection *conn;
674 struct rxrpc_transport *trans;
675 struct rxrpc_skb_priv *sp;
676 struct rxrpc_local *local;
677 struct rxrpc_peer *peer;
678 struct sk_buff *skb;
679 int ret;
680
681 _enter("%p, %d", sk, count);
682
683 ASSERT(!irqs_disabled());
684
685 read_lock_bh(&rxrpc_local_lock);
686 local = sk->sk_user_data;
687 if (local && atomic_read(&local->usage) > 0)
688 rxrpc_get_local(local);
689 else
690 local = NULL;
691 read_unlock_bh(&rxrpc_local_lock);
692 if (!local) {
693 _leave(" [local dead]");
694 return;
695 }
696
697 skb = skb_recv_datagram(sk, 0, 1, &ret);
698 if (!skb) {
699 rxrpc_put_local(local);
700 if (ret == -EAGAIN)
701 return;
702 _debug("UDP socket error %d", ret);
703 return;
704 }
705
706 rxrpc_new_skb(skb);
707
708 _net("recv skb %p", skb);
709
710 /* we'll probably need to checksum it (didn't call sock_recvmsg) */
711 if (skb_checksum_complete(skb)) {
712 rxrpc_free_skb(skb);
713 rxrpc_put_local(local);
714 UDP_INC_STATS_BH(&init_net, UDP_MIB_INERRORS, 0);
715 _leave(" [CSUM failed]");
716 return;
717 }
718
719 UDP_INC_STATS_BH(&init_net, UDP_MIB_INDATAGRAMS, 0);
720
721 /* the socket buffer we have is owned by UDP, with UDP's data all over
722 * it, but we really want our own */
723 skb_orphan(skb);
724 sp = rxrpc_skb(skb);
725 memset(sp, 0, sizeof(*sp));
726
727 _net("Rx UDP packet from %08x:%04hu",
728 ntohl(ip_hdr(skb)->saddr), ntohs(udp_hdr(skb)->source));
729
730 /* dig out the RxRPC connection details */
731 if (skb_copy_bits(skb, sizeof(struct udphdr), &sp->hdr,
732 sizeof(sp->hdr)) < 0)
733 goto bad_message;
734 if (!pskb_pull(skb, sizeof(struct udphdr) + sizeof(sp->hdr)))
735 BUG();
736
737 _net("Rx RxRPC %s ep=%x call=%x:%x",
738 sp->hdr.flags & RXRPC_CLIENT_INITIATED ? "ToServer" : "ToClient",
739 ntohl(sp->hdr.epoch),
740 ntohl(sp->hdr.cid),
741 ntohl(sp->hdr.callNumber));
742
743 if (sp->hdr.type == 0 || sp->hdr.type >= RXRPC_N_PACKET_TYPES) {
744 _proto("Rx Bad Packet Type %u", sp->hdr.type);
745 goto bad_message;
746 }
747
748 if (sp->hdr.type == RXRPC_PACKET_TYPE_DATA &&
749 (sp->hdr.callNumber == 0 || sp->hdr.seq == 0))
750 goto bad_message;
751
752 peer = rxrpc_find_peer(local, ip_hdr(skb)->saddr, udp_hdr(skb)->source);
753 if (IS_ERR(peer))
754 goto cant_route_call;
755
756 trans = rxrpc_find_transport(local, peer);
757 rxrpc_put_peer(peer);
758 if (!trans)
759 goto cant_route_call;
760
761 conn = rxrpc_find_connection(trans, &sp->hdr);
762 rxrpc_put_transport(trans);
763 if (!conn)
764 goto cant_route_call;
765
766 _debug("CONN %p {%d}", conn, conn->debug_id);
767
768 if (sp->hdr.callNumber == 0)
769 rxrpc_post_packet_to_conn(conn, skb);
770 else
771 rxrpc_post_packet_to_call(conn, skb);
772 rxrpc_put_connection(conn);
773 rxrpc_put_local(local);
774 return;
775
776cant_route_call:
777 _debug("can't route call");
778 if (sp->hdr.flags & RXRPC_CLIENT_INITIATED &&
779 sp->hdr.type == RXRPC_PACKET_TYPE_DATA) {
780 if (sp->hdr.seq == cpu_to_be32(1)) {
781 _debug("first packet");
782 skb_queue_tail(&local->accept_queue, skb);
783 rxrpc_queue_work(&local->acceptor);
784 rxrpc_put_local(local);
785 _leave(" [incoming]");
786 return;
787 }
788 skb->priority = RX_INVALID_OPERATION;
789 } else {
790 skb->priority = RX_CALL_DEAD;
791 }
792
793 _debug("reject");
794 rxrpc_reject_packet(local, skb);
795 rxrpc_put_local(local);
796 _leave(" [no call]");
797 return;
798
799bad_message:
800 skb->priority = RX_PROTOCOL_ERROR;
801 rxrpc_reject_packet(local, skb);
802 rxrpc_put_local(local);
803 _leave(" [badmsg]");
804}