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