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TOMOYO Linux Cross Reference
Linux/net/rxrpc/ar-input.c

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

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