[RXRPC]: Fix pointers passed to bitops.
[linux-2.6.git] / net / rxrpc / ar-input.c
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 <net/sock.h>
21 #include <net/af_rxrpc.h>
22 #include <net/ip.h>
23 #include "ar-internal.h"
24
25 unsigned long rxrpc_ack_timeout = 1;
26
27 const char *rxrpc_pkts[] = {
28         "?00",
29         "DATA", "ACK", "BUSY", "ABORT", "ACKALL", "CHALL", "RESP", "DEBUG",
30         "?09", "?10", "?11", "?12", "?13", "?14", "?15"
31 };
32
33 /*
34  * queue a packet for recvmsg to pass to userspace
35  * - the caller must hold a lock on call->lock
36  * - must not be called with interrupts disabled (sk_filter() disables BH's)
37  * - eats the packet whether successful or not
38  * - there must be just one reference to the packet, which the caller passes to
39  *   this function
40  */
41 int rxrpc_queue_rcv_skb(struct rxrpc_call *call, struct sk_buff *skb,
42                         bool force, bool terminal)
43 {
44         struct rxrpc_skb_priv *sp;
45         struct rxrpc_sock *rx = call->socket;
46         struct sock *sk;
47         int skb_len, ret;
48
49         _enter(",,%d,%d", force, terminal);
50
51         ASSERT(!irqs_disabled());
52
53         sp = rxrpc_skb(skb);
54         ASSERTCMP(sp->call, ==, call);
55
56         /* if we've already posted the terminal message for a call, then we
57          * don't post any more */
58         if (test_bit(RXRPC_CALL_TERMINAL_MSG, &call->flags)) {
59                 _debug("already terminated");
60                 ASSERTCMP(call->state, >=, RXRPC_CALL_COMPLETE);
61                 skb->destructor = NULL;
62                 sp->call = NULL;
63                 rxrpc_put_call(call);
64                 rxrpc_free_skb(skb);
65                 return 0;
66         }
67
68         sk = &rx->sk;
69
70         if (!force) {
71                 /* cast skb->rcvbuf to unsigned...  It's pointless, but
72                  * reduces number of warnings when compiling with -W
73                  * --ANK */
74 //              ret = -ENOBUFS;
75 //              if (atomic_read(&sk->sk_rmem_alloc) + skb->truesize >=
76 //                  (unsigned) sk->sk_rcvbuf)
77 //                      goto out;
78
79                 ret = sk_filter(sk, skb);
80                 if (ret < 0)
81                         goto out;
82         }
83
84         spin_lock_bh(&sk->sk_receive_queue.lock);
85         if (!test_bit(RXRPC_CALL_TERMINAL_MSG, &call->flags) &&
86             !test_bit(RXRPC_CALL_RELEASED, &call->flags) &&
87             call->socket->sk.sk_state != RXRPC_CLOSE) {
88                 skb->destructor = rxrpc_packet_destructor;
89                 skb->dev = NULL;
90                 skb->sk = sk;
91                 atomic_add(skb->truesize, &sk->sk_rmem_alloc);
92
93                 if (terminal) {
94                         _debug("<<<< TERMINAL MESSAGE >>>>");
95                         set_bit(RXRPC_CALL_TERMINAL_MSG, &call->flags);
96                 }
97
98                 /* allow interception by a kernel service */
99                 if (rx->interceptor) {
100                         rx->interceptor(sk, call->user_call_ID, skb);
101                         spin_unlock_bh(&sk->sk_receive_queue.lock);
102                 } else {
103
104                         /* Cache the SKB length before we tack it onto the
105                          * receive queue.  Once it is added it no longer
106                          * belongs to us and may be freed by other threads of
107                          * control pulling packets from the queue */
108                         skb_len = skb->len;
109
110                         _net("post skb %p", skb);
111                         __skb_queue_tail(&sk->sk_receive_queue, skb);
112                         spin_unlock_bh(&sk->sk_receive_queue.lock);
113
114                         if (!sock_flag(sk, SOCK_DEAD))
115                                 sk->sk_data_ready(sk, skb_len);
116                 }
117                 skb = NULL;
118         } else {
119                 spin_unlock_bh(&sk->sk_receive_queue.lock);
120         }
121         ret = 0;
122
123 out:
124         /* release the socket buffer */
125         if (skb) {
126                 skb->destructor = NULL;
127                 sp->call = NULL;
128                 rxrpc_put_call(call);
129                 rxrpc_free_skb(skb);
130         }
131
132         _leave(" = %d", ret);
133         return ret;
134 }
135
136 /*
137  * process a DATA packet, posting the packet to the appropriate queue
138  * - eats the packet if successful
139  */
140 static int rxrpc_fast_process_data(struct rxrpc_call *call,
141                                    struct sk_buff *skb, u32 seq)
142 {
143         struct rxrpc_skb_priv *sp;
144         bool terminal;
145         int ret, ackbit, ack;
146
147         _enter("{%u,%u},,{%u}", call->rx_data_post, call->rx_first_oos, seq);
148
149         sp = rxrpc_skb(skb);
150         ASSERTCMP(sp->call, ==, NULL);
151
152         spin_lock(&call->lock);
153
154         if (call->state > RXRPC_CALL_COMPLETE)
155                 goto discard;
156
157         ASSERTCMP(call->rx_data_expect, >=, call->rx_data_post);
158         ASSERTCMP(call->rx_data_post, >=, call->rx_data_recv);
159         ASSERTCMP(call->rx_data_recv, >=, call->rx_data_eaten);
160
161         if (seq < call->rx_data_post) {
162                 _debug("dup #%u [-%u]", seq, call->rx_data_post);
163                 ack = RXRPC_ACK_DUPLICATE;
164                 ret = -ENOBUFS;
165                 goto discard_and_ack;
166         }
167
168         /* we may already have the packet in the out of sequence queue */
169         ackbit = seq - (call->rx_data_eaten + 1);
170         ASSERTCMP(ackbit, >=, 0);
171         if (__test_and_set_bit(ackbit, call->ackr_window)) {
172                 _debug("dup oos #%u [%u,%u]",
173                        seq, call->rx_data_eaten, call->rx_data_post);
174                 ack = RXRPC_ACK_DUPLICATE;
175                 goto discard_and_ack;
176         }
177
178         if (seq >= call->ackr_win_top) {
179                 _debug("exceed #%u [%u]", seq, call->ackr_win_top);
180                 __clear_bit(ackbit, call->ackr_window);
181                 ack = RXRPC_ACK_EXCEEDS_WINDOW;
182                 goto discard_and_ack;
183         }
184
185         if (seq == call->rx_data_expect) {
186                 clear_bit(RXRPC_CALL_EXPECT_OOS, &call->flags);
187                 call->rx_data_expect++;
188         } else if (seq > call->rx_data_expect) {
189                 _debug("oos #%u [%u]", seq, call->rx_data_expect);
190                 call->rx_data_expect = seq + 1;
191                 if (test_and_set_bit(RXRPC_CALL_EXPECT_OOS, &call->flags)) {
192                         ack = RXRPC_ACK_OUT_OF_SEQUENCE;
193                         goto enqueue_and_ack;
194                 }
195                 goto enqueue_packet;
196         }
197
198         if (seq != call->rx_data_post) {
199                 _debug("ahead #%u [%u]", seq, call->rx_data_post);
200                 goto enqueue_packet;
201         }
202
203         if (test_bit(RXRPC_CALL_RCVD_LAST, &call->flags))
204                 goto protocol_error;
205
206         /* if the packet need security things doing to it, then it goes down
207          * the slow path */
208         if (call->conn->security)
209                 goto enqueue_packet;
210
211         sp->call = call;
212         rxrpc_get_call(call);
213         terminal = ((sp->hdr.flags & RXRPC_LAST_PACKET) &&
214                     !(sp->hdr.flags & RXRPC_CLIENT_INITIATED));
215         ret = rxrpc_queue_rcv_skb(call, skb, false, terminal);
216         if (ret < 0) {
217                 if (ret == -ENOMEM || ret == -ENOBUFS) {
218                         __clear_bit(ackbit, call->ackr_window);
219                         ack = RXRPC_ACK_NOSPACE;
220                         goto discard_and_ack;
221                 }
222                 goto out;
223         }
224
225         skb = NULL;
226
227         _debug("post #%u", seq);
228         ASSERTCMP(call->rx_data_post, ==, seq);
229         call->rx_data_post++;
230
231         if (sp->hdr.flags & RXRPC_LAST_PACKET)
232                 set_bit(RXRPC_CALL_RCVD_LAST, &call->flags);
233
234         /* if we've reached an out of sequence packet then we need to drain
235          * that queue into the socket Rx queue now */
236         if (call->rx_data_post == call->rx_first_oos) {
237                 _debug("drain rx oos now");
238                 read_lock(&call->state_lock);
239                 if (call->state < RXRPC_CALL_COMPLETE &&
240                     !test_and_set_bit(RXRPC_CALL_DRAIN_RX_OOS, &call->events))
241                         rxrpc_queue_call(call);
242                 read_unlock(&call->state_lock);
243         }
244
245         spin_unlock(&call->lock);
246         atomic_inc(&call->ackr_not_idle);
247         rxrpc_propose_ACK(call, RXRPC_ACK_DELAY, sp->hdr.serial, false);
248         _leave(" = 0 [posted]");
249         return 0;
250
251 protocol_error:
252         ret = -EBADMSG;
253 out:
254         spin_unlock(&call->lock);
255         _leave(" = %d", ret);
256         return ret;
257
258 discard_and_ack:
259         _debug("discard and ACK packet %p", skb);
260         __rxrpc_propose_ACK(call, ack, sp->hdr.serial, true);
261 discard:
262         spin_unlock(&call->lock);
263         rxrpc_free_skb(skb);
264         _leave(" = 0 [discarded]");
265         return 0;
266
267 enqueue_and_ack:
268         __rxrpc_propose_ACK(call, ack, sp->hdr.serial, true);
269 enqueue_packet:
270         _net("defer skb %p", skb);
271         spin_unlock(&call->lock);
272         skb_queue_tail(&call->rx_queue, skb);
273         atomic_inc(&call->ackr_not_idle);
274         read_lock(&call->state_lock);
275         if (call->state < RXRPC_CALL_DEAD)
276                 rxrpc_queue_call(call);
277         read_unlock(&call->state_lock);
278         _leave(" = 0 [queued]");
279         return 0;
280 }
281
282 /*
283  * assume an implicit ACKALL of the transmission phase of a client socket upon
284  * reception of the first reply packet
285  */
286 static void rxrpc_assume_implicit_ackall(struct rxrpc_call *call, u32 serial)
287 {
288         write_lock_bh(&call->state_lock);
289
290         switch (call->state) {
291         case RXRPC_CALL_CLIENT_AWAIT_REPLY:
292                 call->state = RXRPC_CALL_CLIENT_RECV_REPLY;
293                 call->acks_latest = serial;
294
295                 _debug("implicit ACKALL %%%u", call->acks_latest);
296                 set_bit(RXRPC_CALL_RCVD_ACKALL, &call->events);
297                 write_unlock_bh(&call->state_lock);
298
299                 if (try_to_del_timer_sync(&call->resend_timer) >= 0) {
300                         clear_bit(RXRPC_CALL_RESEND_TIMER, &call->events);
301                         clear_bit(RXRPC_CALL_RESEND, &call->events);
302                         clear_bit(RXRPC_CALL_RUN_RTIMER, &call->flags);
303                 }
304                 break;
305
306         default:
307                 write_unlock_bh(&call->state_lock);
308                 break;
309         }
310 }
311
312 /*
313  * post an incoming packet to the nominated call to deal with
314  * - must get rid of the sk_buff, either by freeing it or by queuing it
315  */
316 void rxrpc_fast_process_packet(struct rxrpc_call *call, struct sk_buff *skb)
317 {
318         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
319         __be32 _abort_code;
320         u32 serial, hi_serial, seq, abort_code;
321
322         _enter("%p,%p", call, skb);
323
324         ASSERT(!irqs_disabled());
325
326 #if 0 // INJECT RX ERROR
327         if (sp->hdr.type == RXRPC_PACKET_TYPE_DATA) {
328                 static int skip = 0;
329                 if (++skip == 3) {
330                         printk("DROPPED 3RD PACKET!!!!!!!!!!!!!\n");
331                         skip = 0;
332                         goto free_packet;
333                 }
334         }
335 #endif
336
337         /* track the latest serial number on this connection for ACK packet
338          * information */
339         serial = ntohl(sp->hdr.serial);
340         hi_serial = atomic_read(&call->conn->hi_serial);
341         while (serial > hi_serial)
342                 hi_serial = atomic_cmpxchg(&call->conn->hi_serial, hi_serial,
343                                            serial);
344
345         /* request ACK generation for any ACK or DATA packet that requests
346          * it */
347         if (sp->hdr.flags & RXRPC_REQUEST_ACK) {
348                 _proto("ACK Requested on %%%u", serial);
349                 rxrpc_propose_ACK(call, RXRPC_ACK_REQUESTED, sp->hdr.serial,
350                                   !(sp->hdr.flags & RXRPC_MORE_PACKETS));
351         }
352
353         switch (sp->hdr.type) {
354         case RXRPC_PACKET_TYPE_ABORT:
355                 _debug("abort");
356
357                 if (skb_copy_bits(skb, 0, &_abort_code,
358                                   sizeof(_abort_code)) < 0)
359                         goto protocol_error;
360
361                 abort_code = ntohl(_abort_code);
362                 _proto("Rx ABORT %%%u { %x }", serial, abort_code);
363
364                 write_lock_bh(&call->state_lock);
365                 if (call->state < RXRPC_CALL_COMPLETE) {
366                         call->state = RXRPC_CALL_REMOTELY_ABORTED;
367                         call->abort_code = abort_code;
368                         set_bit(RXRPC_CALL_RCVD_ABORT, &call->events);
369                         rxrpc_queue_call(call);
370                 }
371                 goto free_packet_unlock;
372
373         case RXRPC_PACKET_TYPE_BUSY:
374                 _proto("Rx BUSY %%%u", serial);
375
376                 if (call->conn->out_clientflag)
377                         goto protocol_error;
378
379                 write_lock_bh(&call->state_lock);
380                 switch (call->state) {
381                 case RXRPC_CALL_CLIENT_SEND_REQUEST:
382                         call->state = RXRPC_CALL_SERVER_BUSY;
383                         set_bit(RXRPC_CALL_RCVD_BUSY, &call->events);
384                         rxrpc_queue_call(call);
385                 case RXRPC_CALL_SERVER_BUSY:
386                         goto free_packet_unlock;
387                 default:
388                         goto protocol_error_locked;
389                 }
390
391         default:
392                 _proto("Rx %s %%%u", rxrpc_pkts[sp->hdr.type], serial);
393                 goto protocol_error;
394
395         case RXRPC_PACKET_TYPE_DATA:
396                 seq = ntohl(sp->hdr.seq);
397
398                 _proto("Rx DATA %%%u { #%u }", serial, seq);
399
400                 if (seq == 0)
401                         goto protocol_error;
402
403                 call->ackr_prev_seq = sp->hdr.seq;
404
405                 /* received data implicitly ACKs all of the request packets we
406                  * sent when we're acting as a client */
407                 if (call->state == RXRPC_CALL_CLIENT_AWAIT_REPLY)
408                         rxrpc_assume_implicit_ackall(call, serial);
409
410                 switch (rxrpc_fast_process_data(call, skb, seq)) {
411                 case 0:
412                         skb = NULL;
413                         goto done;
414
415                 default:
416                         BUG();
417
418                         /* data packet received beyond the last packet */
419                 case -EBADMSG:
420                         goto protocol_error;
421                 }
422
423         case RXRPC_PACKET_TYPE_ACK:
424                 /* ACK processing is done in process context */
425                 read_lock_bh(&call->state_lock);
426                 if (call->state < RXRPC_CALL_DEAD) {
427                         skb_queue_tail(&call->rx_queue, skb);
428                         rxrpc_queue_call(call);
429                         skb = NULL;
430                 }
431                 read_unlock_bh(&call->state_lock);
432                 goto free_packet;
433         }
434
435 protocol_error:
436         _debug("protocol error");
437         write_lock_bh(&call->state_lock);
438 protocol_error_locked:
439         if (call->state <= RXRPC_CALL_COMPLETE) {
440                 call->state = RXRPC_CALL_LOCALLY_ABORTED;
441                 call->abort_code = RX_PROTOCOL_ERROR;
442                 set_bit(RXRPC_CALL_ABORT, &call->events);
443                 rxrpc_queue_call(call);
444         }
445 free_packet_unlock:
446         write_unlock_bh(&call->state_lock);
447 free_packet:
448         rxrpc_free_skb(skb);
449 done:
450         _leave("");
451 }
452
453 /*
454  * split up a jumbo data packet
455  */
456 static void rxrpc_process_jumbo_packet(struct rxrpc_call *call,
457                                        struct sk_buff *jumbo)
458 {
459         struct rxrpc_jumbo_header jhdr;
460         struct rxrpc_skb_priv *sp;
461         struct sk_buff *part;
462
463         _enter(",{%u,%u}", jumbo->data_len, jumbo->len);
464
465         sp = rxrpc_skb(jumbo);
466
467         do {
468                 sp->hdr.flags &= ~RXRPC_JUMBO_PACKET;
469
470                 /* make a clone to represent the first subpacket in what's left
471                  * of the jumbo packet */
472                 part = skb_clone(jumbo, GFP_ATOMIC);
473                 if (!part) {
474                         /* simply ditch the tail in the event of ENOMEM */
475                         pskb_trim(jumbo, RXRPC_JUMBO_DATALEN);
476                         break;
477                 }
478                 rxrpc_new_skb(part);
479
480                 pskb_trim(part, RXRPC_JUMBO_DATALEN);
481
482                 if (!pskb_pull(jumbo, RXRPC_JUMBO_DATALEN))
483                         goto protocol_error;
484
485                 if (skb_copy_bits(jumbo, 0, &jhdr, sizeof(jhdr)) < 0)
486                         goto protocol_error;
487                 if (!pskb_pull(jumbo, sizeof(jhdr)))
488                         BUG();
489
490                 sp->hdr.seq     = htonl(ntohl(sp->hdr.seq) + 1);
491                 sp->hdr.serial  = htonl(ntohl(sp->hdr.serial) + 1);
492                 sp->hdr.flags   = jhdr.flags;
493                 sp->hdr._rsvd   = jhdr._rsvd;
494
495                 _proto("Rx DATA Jumbo %%%u", ntohl(sp->hdr.serial) - 1);
496
497                 rxrpc_fast_process_packet(call, part);
498                 part = NULL;
499
500         } while (sp->hdr.flags & RXRPC_JUMBO_PACKET);
501
502         rxrpc_fast_process_packet(call, jumbo);
503         _leave("");
504         return;
505
506 protocol_error:
507         _debug("protocol error");
508         rxrpc_free_skb(part);
509         rxrpc_free_skb(jumbo);
510         write_lock_bh(&call->state_lock);
511         if (call->state <= RXRPC_CALL_COMPLETE) {
512                 call->state = RXRPC_CALL_LOCALLY_ABORTED;
513                 call->abort_code = RX_PROTOCOL_ERROR;
514                 set_bit(RXRPC_CALL_ABORT, &call->events);
515                 rxrpc_queue_call(call);
516         }
517         write_unlock_bh(&call->state_lock);
518         _leave("");
519 }
520
521 /*
522  * post an incoming packet to the appropriate call/socket to deal with
523  * - must get rid of the sk_buff, either by freeing it or by queuing it
524  */
525 static void rxrpc_post_packet_to_call(struct rxrpc_connection *conn,
526                                       struct sk_buff *skb)
527 {
528         struct rxrpc_skb_priv *sp;
529         struct rxrpc_call *call;
530         struct rb_node *p;
531         __be32 call_id;
532
533         _enter("%p,%p", conn, skb);
534
535         read_lock_bh(&conn->lock);
536
537         sp = rxrpc_skb(skb);
538
539         /* look at extant calls by channel number first */
540         call = conn->channels[ntohl(sp->hdr.cid) & RXRPC_CHANNELMASK];
541         if (!call || call->call_id != sp->hdr.callNumber)
542                 goto call_not_extant;
543
544         _debug("extant call [%d]", call->state);
545         ASSERTCMP(call->conn, ==, conn);
546
547         read_lock(&call->state_lock);
548         switch (call->state) {
549         case RXRPC_CALL_LOCALLY_ABORTED:
550                 if (!test_and_set_bit(RXRPC_CALL_ABORT, &call->events))
551                         rxrpc_queue_call(call);
552         case RXRPC_CALL_REMOTELY_ABORTED:
553         case RXRPC_CALL_NETWORK_ERROR:
554         case RXRPC_CALL_DEAD:
555                 goto free_unlock;
556         default:
557                 break;
558         }
559
560         read_unlock(&call->state_lock);
561         rxrpc_get_call(call);
562         read_unlock_bh(&conn->lock);
563
564         if (sp->hdr.type == RXRPC_PACKET_TYPE_DATA &&
565             sp->hdr.flags & RXRPC_JUMBO_PACKET)
566                 rxrpc_process_jumbo_packet(call, skb);
567         else
568                 rxrpc_fast_process_packet(call, skb);
569
570         rxrpc_put_call(call);
571         goto done;
572
573 call_not_extant:
574         /* search the completed calls in case what we're dealing with is
575          * there */
576         _debug("call not extant");
577
578         call_id = sp->hdr.callNumber;
579         p = conn->calls.rb_node;
580         while (p) {
581                 call = rb_entry(p, struct rxrpc_call, conn_node);
582
583                 if (call_id < call->call_id)
584                         p = p->rb_left;
585                 else if (call_id > call->call_id)
586                         p = p->rb_right;
587                 else
588                         goto found_completed_call;
589         }
590
591 dead_call:
592         /* it's a either a really old call that we no longer remember or its a
593          * new incoming call */
594         read_unlock_bh(&conn->lock);
595
596         if (sp->hdr.flags & RXRPC_CLIENT_INITIATED &&
597             sp->hdr.seq == __constant_cpu_to_be32(1)) {
598                 _debug("incoming call");
599                 skb_queue_tail(&conn->trans->local->accept_queue, skb);
600                 rxrpc_queue_work(&conn->trans->local->acceptor);
601                 goto done;
602         }
603
604         _debug("dead call");
605         skb->priority = RX_CALL_DEAD;
606         rxrpc_reject_packet(conn->trans->local, skb);
607         goto done;
608
609         /* resend last packet of a completed call
610          * - client calls may have been aborted or ACK'd
611          * - server calls may have been aborted
612          */
613 found_completed_call:
614         _debug("completed call");
615
616         if (atomic_read(&call->usage) == 0)
617                 goto dead_call;
618
619         /* synchronise any state changes */
620         read_lock(&call->state_lock);
621         ASSERTIFCMP(call->state != RXRPC_CALL_CLIENT_FINAL_ACK,
622                     call->state, >=, RXRPC_CALL_COMPLETE);
623
624         if (call->state == RXRPC_CALL_LOCALLY_ABORTED ||
625             call->state == RXRPC_CALL_REMOTELY_ABORTED ||
626             call->state == RXRPC_CALL_DEAD) {
627                 read_unlock(&call->state_lock);
628                 goto dead_call;
629         }
630
631         if (call->conn->in_clientflag) {
632                 read_unlock(&call->state_lock);
633                 goto dead_call; /* complete server call */
634         }
635
636         _debug("final ack again");
637         rxrpc_get_call(call);
638         set_bit(RXRPC_CALL_ACK_FINAL, &call->events);
639         rxrpc_queue_call(call);
640
641 free_unlock:
642         read_unlock(&call->state_lock);
643         read_unlock_bh(&conn->lock);
644         rxrpc_free_skb(skb);
645 done:
646         _leave("");
647 }
648
649 /*
650  * post connection-level events to the connection
651  * - this includes challenges, responses and some aborts
652  */
653 static void rxrpc_post_packet_to_conn(struct rxrpc_connection *conn,
654                                       struct sk_buff *skb)
655 {
656         _enter("%p,%p", conn, skb);
657
658         atomic_inc(&conn->usage);
659         skb_queue_tail(&conn->rx_queue, skb);
660         rxrpc_queue_conn(conn);
661 }
662
663 /*
664  * handle data received on the local endpoint
665  * - may be called in interrupt context
666  */
667 void rxrpc_data_ready(struct sock *sk, int count)
668 {
669         struct rxrpc_connection *conn;
670         struct rxrpc_transport *trans;
671         struct rxrpc_skb_priv *sp;
672         struct rxrpc_local *local;
673         struct rxrpc_peer *peer;
674         struct sk_buff *skb;
675         int ret;
676
677         _enter("%p, %d", sk, count);
678
679         ASSERT(!irqs_disabled());
680
681         read_lock_bh(&rxrpc_local_lock);
682         local = sk->sk_user_data;
683         if (local && atomic_read(&local->usage) > 0)
684                 rxrpc_get_local(local);
685         else
686                 local = NULL;
687         read_unlock_bh(&rxrpc_local_lock);
688         if (!local) {
689                 _leave(" [local dead]");
690                 return;
691         }
692
693         skb = skb_recv_datagram(sk, 0, 1, &ret);
694         if (!skb) {
695                 rxrpc_put_local(local);
696                 if (ret == -EAGAIN)
697                         return;
698                 _debug("UDP socket error %d", ret);
699                 return;
700         }
701
702         rxrpc_new_skb(skb);
703
704         _net("recv skb %p", skb);
705
706         /* we'll probably need to checksum it (didn't call sock_recvmsg) */
707         if (skb_checksum_complete(skb)) {
708                 rxrpc_free_skb(skb);
709                 rxrpc_put_local(local);
710                 _leave(" [CSUM failed]");
711                 return;
712         }
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 */
716         skb_orphan(skb);
717         sp = rxrpc_skb(skb);
718         memset(sp, 0, sizeof(*sp));
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 (skb_copy_bits(skb, sizeof(struct udphdr), &sp->hdr,
725                           sizeof(sp->hdr)) < 0)
726                 goto bad_message;
727         if (!pskb_pull(skb, sizeof(struct udphdr) + sizeof(sp->hdr)))
728                 BUG();
729
730         _net("Rx RxRPC %s ep=%x call=%x:%x",
731              sp->hdr.flags & RXRPC_CLIENT_INITIATED ? "ToServer" : "ToClient",
732              ntohl(sp->hdr.epoch),
733              ntohl(sp->hdr.cid),
734              ntohl(sp->hdr.callNumber));
735
736         if (sp->hdr.type == 0 || sp->hdr.type >= RXRPC_N_PACKET_TYPES) {
737                 _proto("Rx Bad Packet Type %u", sp->hdr.type);
738                 goto bad_message;
739         }
740
741         if (sp->hdr.type == RXRPC_PACKET_TYPE_DATA &&
742             (sp->hdr.callNumber == 0 || sp->hdr.seq == 0))
743                 goto bad_message;
744
745         peer = rxrpc_find_peer(local, ip_hdr(skb)->saddr, udp_hdr(skb)->source);
746         if (IS_ERR(peer))
747                 goto cant_route_call;
748
749         trans = rxrpc_find_transport(local, peer);
750         rxrpc_put_peer(peer);
751         if (!trans)
752                 goto cant_route_call;
753
754         conn = rxrpc_find_connection(trans, &sp->hdr);
755         rxrpc_put_transport(trans);
756         if (!conn)
757                 goto cant_route_call;
758
759         _debug("CONN %p {%d}", conn, conn->debug_id);
760
761         if (sp->hdr.callNumber == 0)
762                 rxrpc_post_packet_to_conn(conn, skb);
763         else
764                 rxrpc_post_packet_to_call(conn, skb);
765         rxrpc_put_connection(conn);
766         rxrpc_put_local(local);
767         return;
768
769 cant_route_call:
770         _debug("can't route call");
771         if (sp->hdr.flags & RXRPC_CLIENT_INITIATED &&
772             sp->hdr.type == RXRPC_PACKET_TYPE_DATA) {
773                 if (sp->hdr.seq == __constant_cpu_to_be32(1)) {
774                         _debug("first packet");
775                         skb_queue_tail(&local->accept_queue, skb);
776                         rxrpc_queue_work(&local->acceptor);
777                         rxrpc_put_local(local);
778                         _leave(" [incoming]");
779                         return;
780                 }
781                 skb->priority = RX_INVALID_OPERATION;
782         } else {
783                 skb->priority = RX_CALL_DEAD;
784         }
785
786         _debug("reject");
787         rxrpc_reject_packet(local, skb);
788         rxrpc_put_local(local);
789         _leave(" [no call]");
790         return;
791
792 bad_message:
793         skb->priority = RX_PROTOCOL_ERROR;
794         rxrpc_reject_packet(local, skb);
795         rxrpc_put_local(local);
796         _leave(" [badmsg]");
797 }