ipv6: updates to privacy addresses per RFC 4941
[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 <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
28 unsigned long rxrpc_ack_timeout = 1;
29
30 const 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  */
44 int 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
126 out:
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  */
143 static 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
254 protocol_error:
255         ret = -EBADMSG;
256 out:
257         spin_unlock(&call->lock);
258         _leave(" = %d", ret);
259         return ret;
260
261 discard_and_ack:
262         _debug("discard and ACK packet %p", skb);
263         __rxrpc_propose_ACK(call, ack, sp->hdr.serial, true);
264 discard:
265         spin_unlock(&call->lock);
266         rxrpc_free_skb(skb);
267         _leave(" = 0 [discarded]");
268         return 0;
269
270 enqueue_and_ack:
271         __rxrpc_propose_ACK(call, ack, sp->hdr.serial, true);
272 enqueue_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  */
289 static 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  */
319 void 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
439 protocol_error:
440         _debug("protocol error");
441         write_lock_bh(&call->state_lock);
442 protocol_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         }
449 free_packet_unlock:
450         write_unlock_bh(&call->state_lock);
451 free_packet:
452         rxrpc_free_skb(skb);
453 done:
454         _leave("");
455 }
456
457 /*
458  * split up a jumbo data packet
459  */
460 static 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
510 protocol_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  */
529 static 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
577 call_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
595 dead_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          */
617 found_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
645 free_unlock:
646         read_unlock(&call->state_lock);
647         read_unlock_bh(&conn->lock);
648         rxrpc_free_skb(skb);
649 done:
650         _leave("");
651 }
652
653 /*
654  * post connection-level events to the connection
655  * - this includes challenges, responses and some aborts
656  */
657 static 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  */
671 void 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
776 cant_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
799 bad_message:
800         skb->priority = RX_PROTOCOL_ERROR;
801         rxrpc_reject_packet(local, skb);
802         rxrpc_put_local(local);
803         _leave(" [badmsg]");
804 }