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