net/rxrpc/call_event.c

   1 /* Management of Tx window, Tx resend, ACKs and out-of-sequence 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 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  13
  14 #include <linux/module.h>
  15 #include <linux/circ_buf.h>
  16 #include <linux/net.h>
  17 #include <linux/skbuff.h>
  18 #include <linux/slab.h>
  19 #include <linux/udp.h>
  20 #include <net/sock.h>
  21 #include <net/af_rxrpc.h>
  22 #include "ar-internal.h"
  23
  24 /*
  25  * propose an ACK be sent
  26  */
  27 void __rxrpc_propose_ACK(struct rxrpc_call *call, u8 ack_reason,
  28                          u16 skew, u32 serial, bool immediate)
  29 {
  30         unsigned long expiry;
  31         s8 prior = rxrpc_ack_priority[ack_reason];
  32
  33         ASSERTCMP(prior, >, 0);
  34
  35         _enter("{%d},%s,%%%x,%u",
  36                call->debug_id, rxrpc_acks(ack_reason), serial, immediate);
  37
  38         if (prior < rxrpc_ack_priority[call->ackr_reason]) {
  39                 if (immediate)
  40                         goto cancel_timer;
  41                 return;
  42         }
  43
  44         /* update DELAY, IDLE, REQUESTED and PING_RESPONSE ACK serial
  45          * numbers */
  46         if (prior == rxrpc_ack_priority[call->ackr_reason]) {
  47                 if (prior <= 4) {
  48                         call->ackr_skew = skew;
  49                         call->ackr_serial = serial;
  50                 }
  51                 if (immediate)
  52                         goto cancel_timer;
  53                 return;
  54         }
  55
  56         call->ackr_reason = ack_reason;
  57         call->ackr_serial = serial;
  58
  59         switch (ack_reason) {
  60         case RXRPC_ACK_DELAY:
  61                 _debug("run delay timer");
  62                 expiry = rxrpc_soft_ack_delay;
  63                 goto run_timer;
  64
  65         case RXRPC_ACK_IDLE:
  66                 if (!immediate) {
  67                         _debug("run defer timer");
  68                         expiry = rxrpc_idle_ack_delay;
  69                         goto run_timer;
  70                 }
  71                 goto cancel_timer;
  72
  73         case RXRPC_ACK_REQUESTED:
  74                 expiry = rxrpc_requested_ack_delay;
  75                 if (!expiry)
  76                         goto cancel_timer;
  77                 if (!immediate || serial == 1) {
  78                         _debug("run defer timer");
  79                         goto run_timer;
  80                 }
  81
  82         default:
  83                 _debug("immediate ACK");
  84                 goto cancel_timer;
  85         }
  86
  87 run_timer:
  88         expiry += jiffies;
  89         if (!timer_pending(&call->ack_timer) ||
  90             time_after(call->ack_timer.expires, expiry))
  91                 mod_timer(&call->ack_timer, expiry);
  92         return;
  93
  94 cancel_timer:
  95         _debug("cancel timer %%%u", serial);
  96         try_to_del_timer_sync(&call->ack_timer);
  97         read_lock_bh(&call->state_lock);
  98         if (call->state <= RXRPC_CALL_COMPLETE &&
  99             !test_and_set_bit(RXRPC_CALL_EV_ACK, &call->events))
 100                 rxrpc_queue_call(call);
 101         read_unlock_bh(&call->state_lock);
 102 }
 103
 104 /*
 105  * propose an ACK be sent, locking the call structure
 106  */
 107 void rxrpc_propose_ACK(struct rxrpc_call *call, u8 ack_reason,
 108                        u16 skew, u32 serial, bool immediate)
 109 {
 110         s8 prior = rxrpc_ack_priority[ack_reason];
 111
 112         if (prior > rxrpc_ack_priority[call->ackr_reason]) {
 113                 spin_lock_bh(&call->lock);
 114                 __rxrpc_propose_ACK(call, ack_reason, skew, serial, immediate);
 115                 spin_unlock_bh(&call->lock);
 116         }
 117 }
 118
 119 /*
 120  * set the resend timer
 121  */
 122 static void rxrpc_set_resend(struct rxrpc_call *call, u8 resend,
 123                              unsigned long resend_at)
 124 {
 125         read_lock_bh(&call->state_lock);
 126         if (call->state >= RXRPC_CALL_COMPLETE)
 127                 resend = 0;
 128
 129         if (resend & 1) {
 130                 _debug("SET RESEND");
 131                 set_bit(RXRPC_CALL_EV_RESEND, &call->events);
 132         }
 133
 134         if (resend & 2) {
 135                 _debug("MODIFY RESEND TIMER");
 136                 set_bit(RXRPC_CALL_RUN_RTIMER, &call->flags);
 137                 mod_timer(&call->resend_timer, resend_at);
 138         } else {
 139                 _debug("KILL RESEND TIMER");
 140                 del_timer_sync(&call->resend_timer);
 141                 clear_bit(RXRPC_CALL_EV_RESEND_TIMER, &call->events);
 142                 clear_bit(RXRPC_CALL_RUN_RTIMER, &call->flags);
 143         }
 144         read_unlock_bh(&call->state_lock);
 145 }
 146
 147 /*
 148  * resend packets
 149  */
 150 static void rxrpc_resend(struct rxrpc_call *call)
 151 {
 152         struct rxrpc_wire_header *whdr;
 153         struct rxrpc_skb_priv *sp;
 154         struct sk_buff *txb;
 155         unsigned long *p_txb, resend_at;
 156         bool stop;
 157         int loop;
 158         u8 resend;
 159
 160         _enter("{%d,%d,%d,%d},",
 161                call->acks_hard, call->acks_unacked,
 162                atomic_read(&call->sequence),
 163                CIRC_CNT(call->acks_head, call->acks_tail, call->acks_winsz));
 164
 165         stop = false;
 166         resend = 0;
 167         resend_at = 0;
 168
 169         for (loop = call->acks_tail;
 170              loop != call->acks_head || stop;
 171              loop = (loop + 1) &  (call->acks_winsz - 1)
 172              ) {
 173                 p_txb = call->acks_window + loop;
 174                 smp_read_barrier_depends();
 175                 if (*p_txb & 1)
 176                         continue;
 177
 178                 txb = (struct sk_buff *) *p_txb;
 179                 sp = rxrpc_skb(txb);
 180
 181                 if (sp->need_resend) {
 182                         sp->need_resend = false;
 183
 184                         /* each Tx packet has a new serial number */
 185                         sp->hdr.serial = atomic_inc_return(&call->conn->serial);
 186
 187                         whdr = (struct rxrpc_wire_header *)txb->head;
 188                         whdr->serial = htonl(sp->hdr.serial);
 189
 190                         _proto("Tx DATA %%%u { #%d }",
 191                                sp->hdr.serial, sp->hdr.seq);
 192                         if (rxrpc_send_data_packet(call->conn, txb) < 0) {
 193                                 stop = true;
 194                                 sp->resend_at = jiffies + 3;
 195                         } else {
 196                                 sp->resend_at =
 197                                         jiffies + rxrpc_resend_timeout;
 198                         }
 199                 }
 200
 201                 if (time_after_eq(jiffies + 1, sp->resend_at)) {
 202                         sp->need_resend = true;
 203                         resend |= 1;
 204                 } else if (resend & 2) {
 205                         if (time_before(sp->resend_at, resend_at))
 206                                 resend_at = sp->resend_at;
 207                 } else {
 208                         resend_at = sp->resend_at;
 209                         resend |= 2;
 210                 }
 211         }
 212
 213         rxrpc_set_resend(call, resend, resend_at);
 214         _leave("");
 215 }
 216
 217 /*
 218  * handle resend timer expiry
 219  */
 220 static void rxrpc_resend_timer(struct rxrpc_call *call)
 221 {
 222         struct rxrpc_skb_priv *sp;
 223         struct sk_buff *txb;
 224         unsigned long *p_txb, resend_at;
 225         int loop;
 226         u8 resend;
 227
 228         _enter("%d,%d,%d",
 229                call->acks_tail, call->acks_unacked, call->acks_head);
 230
 231         if (call->state >= RXRPC_CALL_COMPLETE)
 232                 return;
 233
 234         resend = 0;
 235         resend_at = 0;
 236
 237         for (loop = call->acks_unacked;
 238              loop != call->acks_head;
 239              loop = (loop + 1) &  (call->acks_winsz - 1)
 240              ) {
 241                 p_txb = call->acks_window + loop;
 242                 smp_read_barrier_depends();
 243                 txb = (struct sk_buff *) (*p_txb & ~1);
 244                 sp = rxrpc_skb(txb);
 245
 246                 ASSERT(!(*p_txb & 1));
 247
 248                 if (sp->need_resend) {
 249                         ;
 250                 } else if (time_after_eq(jiffies + 1, sp->resend_at)) {
 251                         sp->need_resend = true;
 252                         resend |= 1;
 253                 } else if (resend & 2) {
 254                         if (time_before(sp->resend_at, resend_at))
 255                                 resend_at = sp->resend_at;
 256                 } else {
 257                         resend_at = sp->resend_at;
 258                         resend |= 2;
 259                 }
 260         }
 261
 262         rxrpc_set_resend(call, resend, resend_at);
 263         _leave("");
 264 }
 265
 266 /*
 267  * process soft ACKs of our transmitted packets
 268  * - these indicate packets the peer has or has not received, but hasn't yet
 269  *   given to the consumer, and so can still be discarded and re-requested
 270  */
 271 static int rxrpc_process_soft_ACKs(struct rxrpc_call *call,
 272                                    struct rxrpc_ackpacket *ack,
 273                                    struct sk_buff *skb)
 274 {
 275         struct rxrpc_skb_priv *sp;
 276         struct sk_buff *txb;
 277         unsigned long *p_txb, resend_at;
 278         int loop;
 279         u8 sacks[RXRPC_MAXACKS], resend;
 280
 281         _enter("{%d,%d},{%d},",
 282                call->acks_hard,
 283                CIRC_CNT(call->acks_head, call->acks_tail, call->acks_winsz),
 284                ack->nAcks);
 285
 286         if (skb_copy_bits(skb, 0, sacks, ack->nAcks) < 0)
 287                 goto protocol_error;
 288
 289         resend = 0;
 290         resend_at = 0;
 291         for (loop = 0; loop < ack->nAcks; loop++) {
 292                 p_txb = call->acks_window;
 293                 p_txb += (call->acks_tail + loop) & (call->acks_winsz - 1);
 294                 smp_read_barrier_depends();
 295                 txb = (struct sk_buff *) (*p_txb & ~1);
 296                 sp = rxrpc_skb(txb);
 297
 298                 switch (sacks[loop]) {
 299                 case RXRPC_ACK_TYPE_ACK:
 300                         sp->need_resend = false;
 301                         *p_txb |= 1;
 302                         break;
 303                 case RXRPC_ACK_TYPE_NACK:
 304                         sp->need_resend = true;
 305                         *p_txb &= ~1;
 306                         resend = 1;
 307                         break;
 308                 default:
 309                         _debug("Unsupported ACK type %d", sacks[loop]);
 310                         goto protocol_error;
 311                 }
 312         }
 313
 314         smp_mb();
 315         call->acks_unacked = (call->acks_tail + loop) & (call->acks_winsz - 1);
 316
 317         /* anything not explicitly ACK'd is implicitly NACK'd, but may just not
 318          * have been received or processed yet by the far end */
 319         for (loop = call->acks_unacked;
 320              loop != call->acks_head;
 321              loop = (loop + 1) &  (call->acks_winsz - 1)
 322              ) {
 323                 p_txb = call->acks_window + loop;
 324                 smp_read_barrier_depends();
 325                 txb = (struct sk_buff *) (*p_txb & ~1);
 326                 sp = rxrpc_skb(txb);
 327
 328                 if (*p_txb & 1) {
 329                         /* packet must have been discarded */
 330                         sp->need_resend = true;
 331                         *p_txb &= ~1;
 332                         resend |= 1;
 333                 } else if (sp->need_resend) {
 334                         ;
 335                 } else if (time_after_eq(jiffies + 1, sp->resend_at)) {
 336                         sp->need_resend = true;
 337                         resend |= 1;
 338                 } else if (resend & 2) {
 339                         if (time_before(sp->resend_at, resend_at))
 340                                 resend_at = sp->resend_at;
 341                 } else {
 342                         resend_at = sp->resend_at;
 343                         resend |= 2;
 344                 }
 345         }
 346
 347         rxrpc_set_resend(call, resend, resend_at);
 348         _leave(" = 0");
 349         return 0;
 350
 351 protocol_error:
 352         _leave(" = -EPROTO");
 353         return -EPROTO;
 354 }
 355
 356 /*
 357  * discard hard-ACK'd packets from the Tx window
 358  */
 359 static void rxrpc_rotate_tx_window(struct rxrpc_call *call, u32 hard)
 360 {
 361         unsigned long _skb;
 362         int tail = call->acks_tail, old_tail;
 363         int win = CIRC_CNT(call->acks_head, tail, call->acks_winsz);
 364
 365         _enter("{%u,%u},%u", call->acks_hard, win, hard);
 366
 367         ASSERTCMP(hard - call->acks_hard, <=, win);
 368
 369         while (call->acks_hard < hard) {
 370                 smp_read_barrier_depends();
 371                 _skb = call->acks_window[tail] & ~1;
 372                 rxrpc_free_skb((struct sk_buff *) _skb);
 373                 old_tail = tail;
 374                 tail = (tail + 1) & (call->acks_winsz - 1);
 375                 call->acks_tail = tail;
 376                 if (call->acks_unacked == old_tail)
 377                         call->acks_unacked = tail;
 378                 call->acks_hard++;
 379         }
 380
 381         wake_up(&call->tx_waitq);
 382 }
 383
 384 /*
 385  * clear the Tx window in the event of a failure
 386  */
 387 static void rxrpc_clear_tx_window(struct rxrpc_call *call)
 388 {
 389         rxrpc_rotate_tx_window(call, atomic_read(&call->sequence));
 390 }
 391
 392 /*
 393  * drain the out of sequence received packet queue into the packet Rx queue
 394  */
 395 static int rxrpc_drain_rx_oos_queue(struct rxrpc_call *call)
 396 {
 397         struct rxrpc_skb_priv *sp;
 398         struct sk_buff *skb;
 399         bool terminal;
 400         int ret;
 401
 402         _enter("{%d,%d}", call->rx_data_post, call->rx_first_oos);
 403
 404         spin_lock_bh(&call->lock);
 405
 406         ret = -ECONNRESET;
 407         if (test_bit(RXRPC_CALL_RELEASED, &call->flags))
 408                 goto socket_unavailable;
 409
 410         skb = skb_dequeue(&call->rx_oos_queue);
 411         if (skb) {
 412                 rxrpc_see_skb(skb);
 413                 sp = rxrpc_skb(skb);
 414
 415                 _debug("drain OOS packet %d [%d]",
 416                        sp->hdr.seq, call->rx_first_oos);
 417
 418                 if (sp->hdr.seq != call->rx_first_oos) {
 419                         skb_queue_head(&call->rx_oos_queue, skb);
 420                         call->rx_first_oos = rxrpc_skb(skb)->hdr.seq;
 421                         _debug("requeue %p {%u}", skb, call->rx_first_oos);
 422                 } else {
 423                         skb->mark = RXRPC_SKB_MARK_DATA;
 424                         terminal = ((sp->hdr.flags & RXRPC_LAST_PACKET) &&
 425                                 !(sp->hdr.flags & RXRPC_CLIENT_INITIATED));
 426                         ret = rxrpc_queue_rcv_skb(call, skb, true, terminal);
 427                         BUG_ON(ret < 0);
 428                         _debug("drain #%u", call->rx_data_post);
 429                         call->rx_data_post++;
 430
 431                         /* find out what the next packet is */
 432                         skb = skb_peek(&call->rx_oos_queue);
 433                         rxrpc_see_skb(skb);
 434                         if (skb)
 435                                 call->rx_first_oos = rxrpc_skb(skb)->hdr.seq;
 436                         else
 437                                 call->rx_first_oos = 0;
 438                         _debug("peek %p {%u}", skb, call->rx_first_oos);
 439                 }
 440         }
 441
 442         ret = 0;
 443 socket_unavailable:
 444         spin_unlock_bh(&call->lock);
 445         _leave(" = %d", ret);
 446         return ret;
 447 }
 448
 449 /*
 450  * insert an out of sequence packet into the buffer
 451  */
 452 static void rxrpc_insert_oos_packet(struct rxrpc_call *call,
 453                                     struct sk_buff *skb)
 454 {
 455         struct rxrpc_skb_priv *sp, *psp;
 456         struct sk_buff *p;
 457         u32 seq;
 458
 459         sp = rxrpc_skb(skb);
 460         seq = sp->hdr.seq;
 461         _enter(",,{%u}", seq);
 462
 463         skb->destructor = rxrpc_packet_destructor;
 464         ASSERTCMP(sp->call, ==, NULL);
 465         sp->call = call;
 466         rxrpc_get_call(call);
 467         atomic_inc(&call->skb_count);
 468
 469         /* insert into the buffer in sequence order */
 470         spin_lock_bh(&call->lock);
 471
 472         skb_queue_walk(&call->rx_oos_queue, p) {
 473                 psp = rxrpc_skb(p);
 474                 if (psp->hdr.seq > seq) {
 475                         _debug("insert oos #%u before #%u", seq, psp->hdr.seq);
 476                         skb_insert(p, skb, &call->rx_oos_queue);
 477                         goto inserted;
 478                 }
 479         }
 480
 481         _debug("append oos #%u", seq);
 482         skb_queue_tail(&call->rx_oos_queue, skb);
 483 inserted:
 484
 485         /* we might now have a new front to the queue */
 486         if (call->rx_first_oos == 0 || seq < call->rx_first_oos)
 487                 call->rx_first_oos = seq;
 488
 489         read_lock(&call->state_lock);
 490         if (call->state < RXRPC_CALL_COMPLETE &&
 491             call->rx_data_post == call->rx_first_oos) {
 492                 _debug("drain rx oos now");
 493                 set_bit(RXRPC_CALL_EV_DRAIN_RX_OOS, &call->events);
 494         }
 495         read_unlock(&call->state_lock);
 496
 497         spin_unlock_bh(&call->lock);
 498         _leave(" [stored #%u]", call->rx_first_oos);
 499 }
 500
 501 /*
 502  * clear the Tx window on final ACK reception
 503  */
 504 static void rxrpc_zap_tx_window(struct rxrpc_call *call)
 505 {
 506         struct rxrpc_skb_priv *sp;
 507         struct sk_buff *skb;
 508         unsigned long _skb, *acks_window;
 509         u8 winsz = call->acks_winsz;
 510         int tail;
 511
 512         acks_window = call->acks_window;
 513         call->acks_window = NULL;
 514
 515         while (CIRC_CNT(call->acks_head, call->acks_tail, winsz) > 0) {
 516                 tail = call->acks_tail;
 517                 smp_read_barrier_depends();
 518                 _skb = acks_window[tail] & ~1;
 519                 smp_mb();
 520                 call->acks_tail = (call->acks_tail + 1) & (winsz - 1);
 521
 522                 skb = (struct sk_buff *) _skb;
 523                 sp = rxrpc_skb(skb);
 524                 _debug("+++ clear Tx %u", sp->hdr.seq);
 525                 rxrpc_free_skb(skb);
 526         }
 527
 528         kfree(acks_window);
 529 }
 530
 531 /*
 532  * process the extra information that may be appended to an ACK packet
 533  */
 534 static void rxrpc_extract_ackinfo(struct rxrpc_call *call, struct sk_buff *skb,
 535                                   unsigned int latest, int nAcks)
 536 {
 537         struct rxrpc_ackinfo ackinfo;
 538         struct rxrpc_peer *peer;
 539         unsigned int mtu;
 540
 541         if (skb_copy_bits(skb, nAcks + 3, &ackinfo, sizeof(ackinfo)) < 0) {
 542                 _leave(" [no ackinfo]");
 543                 return;
 544         }
 545
 546         _proto("Rx ACK %%%u Info { rx=%u max=%u rwin=%u jm=%u }",
 547                latest,
 548                ntohl(ackinfo.rxMTU), ntohl(ackinfo.maxMTU),
 549                ntohl(ackinfo.rwind), ntohl(ackinfo.jumbo_max));
 550
 551         mtu = min(ntohl(ackinfo.rxMTU), ntohl(ackinfo.maxMTU));
 552
 553         peer = call->conn->params.peer;
 554         if (mtu < peer->maxdata) {
 555                 spin_lock_bh(&peer->lock);
 556                 peer->maxdata = mtu;
 557                 peer->mtu = mtu + peer->hdrsize;
 558                 spin_unlock_bh(&peer->lock);
 559                 _net("Net MTU %u (maxdata %u)", peer->mtu, peer->maxdata);
 560         }
 561 }
 562
 563 /*
 564  * process packets in the reception queue
 565  */
 566 static int rxrpc_process_rx_queue(struct rxrpc_call *call,
 567                                   u32 *_abort_code)
 568 {
 569         struct rxrpc_ackpacket ack;
 570         struct rxrpc_skb_priv *sp;
 571         struct sk_buff *skb;
 572         bool post_ACK;
 573         int latest;
 574         u32 hard, tx;
 575
 576         _enter("");
 577
 578 process_further:
 579         skb = skb_dequeue(&call->rx_queue);
 580         if (!skb)
 581                 return -EAGAIN;
 582
 583         rxrpc_see_skb(skb);
 584         _net("deferred skb %p", skb);
 585
 586         sp = rxrpc_skb(skb);
 587
 588         _debug("process %s [st %d]", rxrpc_pkts[sp->hdr.type], call->state);
 589
 590         post_ACK = false;
 591
 592         switch (sp->hdr.type) {
 593                 /* data packets that wind up here have been received out of
 594                  * order, need security processing or are jumbo packets */
 595         case RXRPC_PACKET_TYPE_DATA:
 596                 _proto("OOSQ DATA %%%u { #%u }", sp->hdr.serial, sp->hdr.seq);
 597
 598                 /* secured packets must be verified and possibly decrypted */
 599                 if (call->conn->security->verify_packet(call, skb,
 600                                                         _abort_code) < 0)
 601                         goto protocol_error;
 602
 603                 rxrpc_insert_oos_packet(call, skb);
 604                 goto process_further;
 605
 606                 /* partial ACK to process */
 607         case RXRPC_PACKET_TYPE_ACK:
 608                 if (skb_copy_bits(skb, 0, &ack, sizeof(ack)) < 0) {
 609                         _debug("extraction failure");
 610                         goto protocol_error;
 611                 }
 612                 if (!skb_pull(skb, sizeof(ack)))
 613                         BUG();
 614
 615                 latest = sp->hdr.serial;
 616                 hard = ntohl(ack.firstPacket);
 617                 tx = atomic_read(&call->sequence);
 618
 619                 _proto("Rx ACK %%%u { m=%hu f=#%u p=#%u s=%%%u r=%s n=%u }",
 620                        latest,
 621                        ntohs(ack.maxSkew),
 622                        hard,
 623                        ntohl(ack.previousPacket),
 624                        ntohl(ack.serial),
 625                        rxrpc_acks(ack.reason),
 626                        ack.nAcks);
 627
 628                 rxrpc_extract_ackinfo(call, skb, latest, ack.nAcks);
 629
 630                 if (ack.reason == RXRPC_ACK_PING) {
 631                         _proto("Rx ACK %%%u PING Request", latest);
 632                         rxrpc_propose_ACK(call, RXRPC_ACK_PING_RESPONSE,
 633                                           skb->priority, sp->hdr.serial, true);
 634                 }
 635
 636                 /* discard any out-of-order or duplicate ACKs */
 637                 if (latest - call->acks_latest <= 0) {
 638                         _debug("discard ACK %d <= %d",
 639                                latest, call->acks_latest);
 640                         goto discard;
 641                 }
 642                 call->acks_latest = latest;
 643
 644                 if (call->state != RXRPC_CALL_CLIENT_SEND_REQUEST &&
 645                     call->state != RXRPC_CALL_CLIENT_AWAIT_REPLY &&
 646                     call->state != RXRPC_CALL_SERVER_SEND_REPLY &&
 647                     call->state != RXRPC_CALL_SERVER_AWAIT_ACK)
 648                         goto discard;
 649
 650                 _debug("Tx=%d H=%u S=%d", tx, call->acks_hard, call->state);
 651
 652                 if (hard > 0) {
 653                         if (hard - 1 > tx) {
 654                                 _debug("hard-ACK'd packet %d not transmitted"
 655                                        " (%d top)",
 656                                        hard - 1, tx);
 657                                 goto protocol_error;
 658                         }
 659
 660                         if ((call->state == RXRPC_CALL_CLIENT_AWAIT_REPLY ||
 661                              call->state == RXRPC_CALL_SERVER_AWAIT_ACK) &&
 662                             hard > tx) {
 663                                 call->acks_hard = tx;
 664                                 goto all_acked;
 665                         }
 666
 667                         smp_rmb();
 668                         rxrpc_rotate_tx_window(call, hard - 1);
 669                 }
 670
 671                 if (ack.nAcks > 0) {
 672                         if (hard - 1 + ack.nAcks > tx) {
 673                                 _debug("soft-ACK'd packet %d+%d not"
 674                                        " transmitted (%d top)",
 675                                        hard - 1, ack.nAcks, tx);
 676                                 goto protocol_error;
 677                         }
 678
 679                         if (rxrpc_process_soft_ACKs(call, &ack, skb) < 0)
 680                                 goto protocol_error;
 681                 }
 682                 goto discard;
 683
 684                 /* complete ACK to process */
 685         case RXRPC_PACKET_TYPE_ACKALL:
 686                 goto all_acked;
 687
 688                 /* abort and busy are handled elsewhere */
 689         case RXRPC_PACKET_TYPE_BUSY:
 690         case RXRPC_PACKET_TYPE_ABORT:
 691                 BUG();
 692
 693                 /* connection level events - also handled elsewhere */
 694         case RXRPC_PACKET_TYPE_CHALLENGE:
 695         case RXRPC_PACKET_TYPE_RESPONSE:
 696         case RXRPC_PACKET_TYPE_DEBUG:
 697                 BUG();
 698         }
 699
 700         /* if we've had a hard ACK that covers all the packets we've sent, then
 701          * that ends that phase of the operation */
 702 all_acked:
 703         write_lock_bh(&call->state_lock);
 704         _debug("ack all %d", call->state);
 705
 706         switch (call->state) {
 707         case RXRPC_CALL_CLIENT_AWAIT_REPLY:
 708                 call->state = RXRPC_CALL_CLIENT_RECV_REPLY;
 709                 break;
 710         case RXRPC_CALL_SERVER_AWAIT_ACK:
 711                 _debug("srv complete");
 712                 call->state = RXRPC_CALL_COMPLETE;
 713                 post_ACK = true;
 714                 break;
 715         case RXRPC_CALL_CLIENT_SEND_REQUEST:
 716         case RXRPC_CALL_SERVER_RECV_REQUEST:
 717                 goto protocol_error_unlock; /* can't occur yet */
 718         default:
 719                 write_unlock_bh(&call->state_lock);
 720                 goto discard; /* assume packet left over from earlier phase */
 721         }
 722
 723         write_unlock_bh(&call->state_lock);
 724
 725         /* if all the packets we sent are hard-ACK'd, then we can discard
 726          * whatever we've got left */
 727         _debug("clear Tx %d",
 728                CIRC_CNT(call->acks_head, call->acks_tail, call->acks_winsz));
 729
 730         del_timer_sync(&call->resend_timer);
 731         clear_bit(RXRPC_CALL_RUN_RTIMER, &call->flags);
 732         clear_bit(RXRPC_CALL_EV_RESEND_TIMER, &call->events);
 733
 734         if (call->acks_window)
 735                 rxrpc_zap_tx_window(call);
 736
 737         if (post_ACK) {
 738                 /* post the final ACK message for userspace to pick up */
 739                 _debug("post ACK");
 740                 skb->mark = RXRPC_SKB_MARK_FINAL_ACK;
 741                 sp->call = call;
 742                 rxrpc_get_call(call);
 743                 atomic_inc(&call->skb_count);
 744                 spin_lock_bh(&call->lock);
 745                 if (rxrpc_queue_rcv_skb(call, skb, true, true) < 0)
 746                         BUG();
 747                 spin_unlock_bh(&call->lock);
 748                 goto process_further;
 749         }
 750
 751 discard:
 752         rxrpc_free_skb(skb);
 753         goto process_further;
 754
 755 protocol_error_unlock:
 756         write_unlock_bh(&call->state_lock);
 757 protocol_error:
 758         rxrpc_free_skb(skb);
 759         _leave(" = -EPROTO");
 760         return -EPROTO;
 761 }
 762
 763 /*
 764  * post a message to the socket Rx queue for recvmsg() to pick up
 765  */
 766 static int rxrpc_post_message(struct rxrpc_call *call, u32 mark, u32 error,
 767                               bool fatal)
 768 {
 769         struct rxrpc_skb_priv *sp;
 770         struct sk_buff *skb;
 771         int ret;
 772
 773         _enter("{%d,%lx},%u,%u,%d",
 774                call->debug_id, call->flags, mark, error, fatal);
 775
 776         /* remove timers and things for fatal messages */
 777         if (fatal) {
 778                 del_timer_sync(&call->resend_timer);
 779                 del_timer_sync(&call->ack_timer);
 780                 clear_bit(RXRPC_CALL_RUN_RTIMER, &call->flags);
 781         }
 782
 783         if (mark != RXRPC_SKB_MARK_NEW_CALL &&
 784             !test_bit(RXRPC_CALL_HAS_USERID, &call->flags)) {
 785                 _leave("[no userid]");
 786                 return 0;
 787         }
 788
 789         if (!test_bit(RXRPC_CALL_TERMINAL_MSG, &call->flags)) {
 790                 skb = alloc_skb(0, GFP_NOFS);
 791                 if (!skb)
 792                         return -ENOMEM;
 793
 794                 rxrpc_new_skb(skb);
 795
 796                 skb->mark = mark;
 797
 798                 sp = rxrpc_skb(skb);
 799                 memset(sp, 0, sizeof(*sp));
 800                 sp->error = error;
 801                 sp->call = call;
 802                 rxrpc_get_call(call);
 803                 atomic_inc(&call->skb_count);
 804
 805                 spin_lock_bh(&call->lock);
 806                 ret = rxrpc_queue_rcv_skb(call, skb, true, fatal);
 807                 spin_unlock_bh(&call->lock);
 808                 BUG_ON(ret < 0);
 809         }
 810
 811         return 0;
 812 }
 813
 814 /*
 815  * handle background processing of incoming call packets and ACK / abort
 816  * generation
 817  */
 818 void rxrpc_process_call(struct work_struct *work)
 819 {
 820         struct rxrpc_call *call =
 821                 container_of(work, struct rxrpc_call, processor);
 822         struct rxrpc_wire_header whdr;
 823         struct rxrpc_ackpacket ack;
 824         struct rxrpc_ackinfo ackinfo;
 825         struct msghdr msg;
 826         struct kvec iov[5];
 827         enum rxrpc_call_event genbit;
 828         unsigned long bits;
 829         __be32 data, pad;
 830         size_t len;
 831         int loop, nbit, ioc, ret, mtu;
 832         u32 serial, abort_code = RX_PROTOCOL_ERROR;
 833         u8 *acks = NULL;
 834
 835         //printk("\n--------------------\n");
 836         _enter("{%d,%s,%lx} [%lu]",
 837                call->debug_id, rxrpc_call_states[call->state], call->events,
 838                (jiffies - call->creation_jif) / (HZ / 10));
 839
 840         if (!call->conn)
 841                 goto skip_msg_init;
 842
 843         /* there's a good chance we're going to have to send a message, so set
 844          * one up in advance */
 845         msg.msg_name    = &call->conn->params.peer->srx.transport;
 846         msg.msg_namelen = call->conn->params.peer->srx.transport_len;
 847         msg.msg_control = NULL;
 848         msg.msg_controllen = 0;
 849         msg.msg_flags   = 0;
 850
 851         whdr.epoch      = htonl(call->conn->proto.epoch);
 852         whdr.cid        = htonl(call->cid);
 853         whdr.callNumber = htonl(call->call_id);
 854         whdr.seq        = 0;
 855         whdr.type       = RXRPC_PACKET_TYPE_ACK;
 856         whdr.flags      = call->conn->out_clientflag;
 857         whdr.userStatus = 0;
 858         whdr.securityIndex = call->conn->security_ix;
 859         whdr._rsvd      = 0;
 860         whdr.serviceId  = htons(call->service_id);
 861
 862         memset(iov, 0, sizeof(iov));
 863         iov[0].iov_base = &whdr;
 864         iov[0].iov_len  = sizeof(whdr);
 865 skip_msg_init:
 866
 867         /* deal with events of a final nature */
 868         if (test_bit(RXRPC_CALL_EV_RCVD_ERROR, &call->events)) {
 869                 enum rxrpc_skb_mark mark;
 870                 int error;
 871
 872                 clear_bit(RXRPC_CALL_EV_CONN_ABORT, &call->events);
 873                 clear_bit(RXRPC_CALL_EV_REJECT_BUSY, &call->events);
 874                 clear_bit(RXRPC_CALL_EV_ABORT, &call->events);
 875
 876                 error = call->error_report;
 877                 if (error < RXRPC_LOCAL_ERROR_OFFSET) {
 878                         mark = RXRPC_SKB_MARK_NET_ERROR;
 879                         _debug("post net error %d", error);
 880                 } else {
 881                         mark = RXRPC_SKB_MARK_LOCAL_ERROR;
 882                         error -= RXRPC_LOCAL_ERROR_OFFSET;
 883                         _debug("post net local error %d", error);
 884                 }
 885
 886                 if (rxrpc_post_message(call, mark, error, true) < 0)
 887                         goto no_mem;
 888                 clear_bit(RXRPC_CALL_EV_RCVD_ERROR, &call->events);
 889                 goto kill_ACKs;
 890         }
 891
 892         if (test_bit(RXRPC_CALL_EV_CONN_ABORT, &call->events)) {
 893                 ASSERTCMP(call->state, >, RXRPC_CALL_COMPLETE);
 894
 895                 clear_bit(RXRPC_CALL_EV_REJECT_BUSY, &call->events);
 896                 clear_bit(RXRPC_CALL_EV_ABORT, &call->events);
 897
 898                 _debug("post conn abort");
 899
 900                 if (rxrpc_post_message(call, RXRPC_SKB_MARK_LOCAL_ERROR,
 901                                        call->conn->error, true) < 0)
 902                         goto no_mem;
 903                 clear_bit(RXRPC_CALL_EV_CONN_ABORT, &call->events);
 904                 goto kill_ACKs;
 905         }
 906
 907         if (test_bit(RXRPC_CALL_EV_REJECT_BUSY, &call->events)) {
 908                 whdr.type = RXRPC_PACKET_TYPE_BUSY;
 909                 genbit = RXRPC_CALL_EV_REJECT_BUSY;
 910                 goto send_message;
 911         }
 912
 913         if (test_bit(RXRPC_CALL_EV_ABORT, &call->events)) {
 914                 ASSERTCMP(call->state, >, RXRPC_CALL_COMPLETE);
 915
 916                 if (rxrpc_post_message(call, RXRPC_SKB_MARK_LOCAL_ERROR,
 917                                        ECONNABORTED, true) < 0)
 918                         goto no_mem;
 919                 whdr.type = RXRPC_PACKET_TYPE_ABORT;
 920                 data = htonl(call->local_abort);
 921                 iov[1].iov_base = &data;
 922                 iov[1].iov_len = sizeof(data);
 923                 genbit = RXRPC_CALL_EV_ABORT;
 924                 goto send_message;
 925         }
 926
 927         if (test_bit(RXRPC_CALL_EV_ACK_FINAL, &call->events)) {
 928                 genbit = RXRPC_CALL_EV_ACK_FINAL;
 929
 930                 ack.bufferSpace = htons(8);
 931                 ack.maxSkew     = 0;
 932                 ack.serial      = 0;
 933                 ack.reason      = RXRPC_ACK_IDLE;
 934                 ack.nAcks       = 0;
 935                 call->ackr_reason = 0;
 936
 937                 spin_lock_bh(&call->lock);
 938                 ack.serial      = htonl(call->ackr_serial);
 939                 ack.previousPacket = htonl(call->ackr_prev_seq);
 940                 ack.firstPacket = htonl(call->rx_data_eaten + 1);
 941                 spin_unlock_bh(&call->lock);
 942
 943                 pad = 0;
 944
 945                 iov[1].iov_base = &ack;
 946                 iov[1].iov_len  = sizeof(ack);
 947                 iov[2].iov_base = &pad;
 948                 iov[2].iov_len  = 3;
 949                 iov[3].iov_base = &ackinfo;
 950                 iov[3].iov_len  = sizeof(ackinfo);
 951                 goto send_ACK;
 952         }
 953
 954         if (call->events & ((1 << RXRPC_CALL_EV_RCVD_BUSY) |
 955                             (1 << RXRPC_CALL_EV_RCVD_ABORT))
 956             ) {
 957                 u32 mark;
 958
 959                 if (test_bit(RXRPC_CALL_EV_RCVD_ABORT, &call->events))
 960                         mark = RXRPC_SKB_MARK_REMOTE_ABORT;
 961                 else
 962                         mark = RXRPC_SKB_MARK_BUSY;
 963
 964                 _debug("post abort/busy");
 965                 rxrpc_clear_tx_window(call);
 966                 if (rxrpc_post_message(call, mark, ECONNABORTED, true) < 0)
 967                         goto no_mem;
 968
 969                 clear_bit(RXRPC_CALL_EV_RCVD_BUSY, &call->events);
 970                 clear_bit(RXRPC_CALL_EV_RCVD_ABORT, &call->events);
 971                 goto kill_ACKs;
 972         }
 973
 974         if (test_and_clear_bit(RXRPC_CALL_EV_RCVD_ACKALL, &call->events)) {
 975                 _debug("do implicit ackall");
 976                 rxrpc_clear_tx_window(call);
 977         }
 978
 979         if (test_bit(RXRPC_CALL_EV_LIFE_TIMER, &call->events)) {
 980                 write_lock_bh(&call->state_lock);
 981                 if (call->state <= RXRPC_CALL_COMPLETE) {
 982                         call->state = RXRPC_CALL_LOCALLY_ABORTED;
 983                         call->local_abort = RX_CALL_TIMEOUT;
 984                         set_bit(RXRPC_CALL_EV_ABORT, &call->events);
 985                 }
 986                 write_unlock_bh(&call->state_lock);
 987
 988                 _debug("post timeout");
 989                 if (rxrpc_post_message(call, RXRPC_SKB_MARK_LOCAL_ERROR,
 990                                        ETIME, true) < 0)
 991                         goto no_mem;
 992
 993                 clear_bit(RXRPC_CALL_EV_LIFE_TIMER, &call->events);
 994                 goto kill_ACKs;
 995         }
 996
 997         /* deal with assorted inbound messages */
 998         if (!skb_queue_empty(&call->rx_queue)) {
 999                 switch (rxrpc_process_rx_queue(call, &abort_code)) {
1000                 case 0:
1001                 case -EAGAIN:
1002                         break;
1003                 case -ENOMEM:
1004                         goto no_mem;
1005                 case -EKEYEXPIRED:
1006                 case -EKEYREJECTED:
1007                 case -EPROTO:
1008                         rxrpc_abort_call(call, abort_code);
1009                         goto kill_ACKs;
1010                 }
1011         }
1012
1013         /* handle resending */
1014         if (test_and_clear_bit(RXRPC_CALL_EV_RESEND_TIMER, &call->events))
1015                 rxrpc_resend_timer(call);
1016         if (test_and_clear_bit(RXRPC_CALL_EV_RESEND, &call->events))
1017                 rxrpc_resend(call);
1018
1019         /* consider sending an ordinary ACK */
1020         if (test_bit(RXRPC_CALL_EV_ACK, &call->events)) {
1021                 _debug("send ACK: window: %d - %d { %lx }",
1022                        call->rx_data_eaten, call->ackr_win_top,
1023                        call->ackr_window[0]);
1024
1025                 if (call->state > RXRPC_CALL_SERVER_ACK_REQUEST &&
1026                     call->ackr_reason != RXRPC_ACK_PING_RESPONSE) {
1027                         /* ACK by sending reply DATA packet in this state */
1028                         clear_bit(RXRPC_CALL_EV_ACK, &call->events);
1029                         goto maybe_reschedule;
1030                 }
1031
1032                 genbit = RXRPC_CALL_EV_ACK;
1033
1034                 acks = kzalloc(call->ackr_win_top - call->rx_data_eaten,
1035                                GFP_NOFS);
1036                 if (!acks)
1037                         goto no_mem;
1038
1039                 //hdr.flags     = RXRPC_SLOW_START_OK;
1040                 ack.bufferSpace = htons(8);
1041                 ack.maxSkew     = 0;
1042
1043                 spin_lock_bh(&call->lock);
1044                 ack.reason      = call->ackr_reason;
1045                 ack.serial      = htonl(call->ackr_serial);
1046                 ack.previousPacket = htonl(call->ackr_prev_seq);
1047                 ack.firstPacket = htonl(call->rx_data_eaten + 1);
1048
1049                 ack.nAcks = 0;
1050                 for (loop = 0; loop < RXRPC_ACKR_WINDOW_ASZ; loop++) {
1051                         nbit = loop * BITS_PER_LONG;
1052                         for (bits = call->ackr_window[loop]; bits; bits >>= 1
1053                              ) {
1054                                 _debug("- l=%d n=%d b=%lx", loop, nbit, bits);
1055                                 if (bits & 1) {
1056                                         acks[nbit] = RXRPC_ACK_TYPE_ACK;
1057                                         ack.nAcks = nbit + 1;
1058                                 }
1059                                 nbit++;
1060                         }
1061                 }
1062                 call->ackr_reason = 0;
1063                 spin_unlock_bh(&call->lock);
1064
1065                 pad = 0;
1066
1067                 iov[1].iov_base = &ack;
1068                 iov[1].iov_len  = sizeof(ack);
1069                 iov[2].iov_base = acks;
1070                 iov[2].iov_len  = ack.nAcks;
1071                 iov[3].iov_base = &pad;
1072                 iov[3].iov_len  = 3;
1073                 iov[4].iov_base = &ackinfo;
1074                 iov[4].iov_len  = sizeof(ackinfo);
1075
1076                 switch (ack.reason) {
1077                 case RXRPC_ACK_REQUESTED:
1078                 case RXRPC_ACK_DUPLICATE:
1079                 case RXRPC_ACK_OUT_OF_SEQUENCE:
1080                 case RXRPC_ACK_EXCEEDS_WINDOW:
1081                 case RXRPC_ACK_NOSPACE:
1082                 case RXRPC_ACK_PING:
1083                 case RXRPC_ACK_PING_RESPONSE:
1084                         goto send_ACK_with_skew;
1085                 case RXRPC_ACK_DELAY:
1086                 case RXRPC_ACK_IDLE:
1087                         goto send_ACK;
1088                 }
1089         }
1090
1091         /* handle completion of security negotiations on an incoming
1092          * connection */
1093         if (test_and_clear_bit(RXRPC_CALL_EV_SECURED, &call->events)) {
1094                 _debug("secured");
1095                 spin_lock_bh(&call->lock);
1096
1097                 if (call->state == RXRPC_CALL_SERVER_SECURING) {
1098                         _debug("securing");
1099                         write_lock(&call->socket->call_lock);
1100                         if (!test_bit(RXRPC_CALL_RELEASED, &call->flags) &&
1101                             !test_bit(RXRPC_CALL_EV_RELEASE, &call->events)) {
1102                                 _debug("not released");
1103                                 call->state = RXRPC_CALL_SERVER_ACCEPTING;
1104                                 list_move_tail(&call->accept_link,
1105                                                &call->socket->acceptq);
1106                         }
1107                         write_unlock(&call->socket->call_lock);
1108                         read_lock(&call->state_lock);
1109                         if (call->state < RXRPC_CALL_COMPLETE)
1110                                 set_bit(RXRPC_CALL_EV_POST_ACCEPT, &call->events);
1111                         read_unlock(&call->state_lock);
1112                 }
1113
1114                 spin_unlock_bh(&call->lock);
1115                 if (!test_bit(RXRPC_CALL_EV_POST_ACCEPT, &call->events))
1116                         goto maybe_reschedule;
1117         }
1118
1119         /* post a notification of an acceptable connection to the app */
1120         if (test_bit(RXRPC_CALL_EV_POST_ACCEPT, &call->events)) {
1121                 _debug("post accept");
1122                 if (rxrpc_post_message(call, RXRPC_SKB_MARK_NEW_CALL,
1123                                        0, false) < 0)
1124                         goto no_mem;
1125                 clear_bit(RXRPC_CALL_EV_POST_ACCEPT, &call->events);
1126                 goto maybe_reschedule;
1127         }
1128
1129         /* handle incoming call acceptance */
1130         if (test_and_clear_bit(RXRPC_CALL_EV_ACCEPTED, &call->events)) {
1131                 _debug("accepted");
1132                 ASSERTCMP(call->rx_data_post, ==, 0);
1133                 call->rx_data_post = 1;
1134                 read_lock_bh(&call->state_lock);
1135                 if (call->state < RXRPC_CALL_COMPLETE)
1136                         set_bit(RXRPC_CALL_EV_DRAIN_RX_OOS, &call->events);
1137                 read_unlock_bh(&call->state_lock);
1138         }
1139
1140         /* drain the out of sequence received packet queue into the packet Rx
1141          * queue */
1142         if (test_and_clear_bit(RXRPC_CALL_EV_DRAIN_RX_OOS, &call->events)) {
1143                 while (call->rx_data_post == call->rx_first_oos)
1144                         if (rxrpc_drain_rx_oos_queue(call) < 0)
1145                                 break;
1146                 goto maybe_reschedule;
1147         }
1148
1149         if (test_bit(RXRPC_CALL_EV_RELEASE, &call->events)) {
1150                 rxrpc_release_call(call);
1151                 clear_bit(RXRPC_CALL_EV_RELEASE, &call->events);
1152         }
1153
1154         /* other events may have been raised since we started checking */
1155         goto maybe_reschedule;
1156
1157 send_ACK_with_skew:
1158         ack.maxSkew = htons(call->ackr_skew);
1159 send_ACK:
1160         mtu = call->conn->params.peer->if_mtu;
1161         mtu -= call->conn->params.peer->hdrsize;
1162         ackinfo.maxMTU  = htonl(mtu);
1163         ackinfo.rwind   = htonl(rxrpc_rx_window_size);
1164
1165         /* permit the peer to send us jumbo packets if it wants to */
1166         ackinfo.rxMTU   = htonl(rxrpc_rx_mtu);
1167         ackinfo.jumbo_max = htonl(rxrpc_rx_jumbo_max);
1168
1169         serial = atomic_inc_return(&call->conn->serial);
1170         whdr.serial = htonl(serial);
1171         _proto("Tx ACK %%%u { m=%hu f=#%u p=#%u s=%%%u r=%s n=%u }",
1172                serial,
1173                ntohs(ack.maxSkew),
1174                ntohl(ack.firstPacket),
1175                ntohl(ack.previousPacket),
1176                ntohl(ack.serial),
1177                rxrpc_acks(ack.reason),
1178                ack.nAcks);
1179
1180         del_timer_sync(&call->ack_timer);
1181         if (ack.nAcks > 0)
1182                 set_bit(RXRPC_CALL_TX_SOFT_ACK, &call->flags);
1183         goto send_message_2;
1184
1185 send_message:
1186         _debug("send message");
1187
1188         serial = atomic_inc_return(&call->conn->serial);
1189         whdr.serial = htonl(serial);
1190         _proto("Tx %s %%%u", rxrpc_pkts[whdr.type], serial);
1191 send_message_2:
1192
1193         len = iov[0].iov_len;
1194         ioc = 1;
1195         if (iov[4].iov_len) {
1196                 ioc = 5;
1197                 len += iov[4].iov_len;
1198                 len += iov[3].iov_len;
1199                 len += iov[2].iov_len;
1200                 len += iov[1].iov_len;
1201         } else if (iov[3].iov_len) {
1202                 ioc = 4;
1203                 len += iov[3].iov_len;
1204                 len += iov[2].iov_len;
1205                 len += iov[1].iov_len;
1206         } else if (iov[2].iov_len) {
1207                 ioc = 3;
1208                 len += iov[2].iov_len;
1209                 len += iov[1].iov_len;
1210         } else if (iov[1].iov_len) {
1211                 ioc = 2;
1212                 len += iov[1].iov_len;
1213         }
1214
1215         ret = kernel_sendmsg(call->conn->params.local->socket,
1216                              &msg, iov, ioc, len);
1217         if (ret < 0) {
1218                 _debug("sendmsg failed: %d", ret);
1219                 read_lock_bh(&call->state_lock);
1220                 if (call->state < RXRPC_CALL_DEAD)
1221                         rxrpc_queue_call(call);
1222                 read_unlock_bh(&call->state_lock);
1223                 goto error;
1224         }
1225
1226         switch (genbit) {
1227         case RXRPC_CALL_EV_ABORT:
1228                 clear_bit(genbit, &call->events);
1229                 clear_bit(RXRPC_CALL_EV_RCVD_ABORT, &call->events);
1230                 goto kill_ACKs;
1231
1232         case RXRPC_CALL_EV_ACK_FINAL:
1233                 write_lock_bh(&call->state_lock);
1234                 if (call->state == RXRPC_CALL_CLIENT_FINAL_ACK)
1235                         call->state = RXRPC_CALL_COMPLETE;
1236                 write_unlock_bh(&call->state_lock);
1237                 goto kill_ACKs;
1238
1239         default:
1240                 clear_bit(genbit, &call->events);
1241                 switch (call->state) {
1242                 case RXRPC_CALL_CLIENT_AWAIT_REPLY:
1243                 case RXRPC_CALL_CLIENT_RECV_REPLY:
1244                 case RXRPC_CALL_SERVER_RECV_REQUEST:
1245                 case RXRPC_CALL_SERVER_ACK_REQUEST:
1246                         _debug("start ACK timer");
1247                         rxrpc_propose_ACK(call, RXRPC_ACK_DELAY,
1248                                           call->ackr_skew, call->ackr_serial,
1249                                           false);
1250                 default:
1251                         break;
1252                 }
1253                 goto maybe_reschedule;
1254         }
1255
1256 kill_ACKs:
1257         del_timer_sync(&call->ack_timer);
1258         if (test_and_clear_bit(RXRPC_CALL_EV_ACK_FINAL, &call->events))
1259                 rxrpc_put_call(call);
1260         clear_bit(RXRPC_CALL_EV_ACK, &call->events);
1261
1262 maybe_reschedule:
1263         if (call->events || !skb_queue_empty(&call->rx_queue)) {
1264                 read_lock_bh(&call->state_lock);
1265                 if (call->state < RXRPC_CALL_DEAD)
1266                         rxrpc_queue_call(call);
1267                 read_unlock_bh(&call->state_lock);
1268         }
1269
1270         /* don't leave aborted connections on the accept queue */
1271         if (call->state >= RXRPC_CALL_COMPLETE &&
1272             !list_empty(&call->accept_link)) {
1273                 _debug("X unlinking once-pending call %p { e=%lx f=%lx c=%x }",
1274                        call, call->events, call->flags, call->conn->proto.cid);
1275
1276                 read_lock_bh(&call->state_lock);
1277                 if (!test_bit(RXRPC_CALL_RELEASED, &call->flags) &&
1278                     !test_and_set_bit(RXRPC_CALL_EV_RELEASE, &call->events))
1279                         rxrpc_queue_call(call);
1280                 read_unlock_bh(&call->state_lock);
1281         }
1282
1283 error:
1284         kfree(acks);
1285
1286         /* because we don't want two CPUs both processing the work item for one
1287          * call at the same time, we use a flag to note when it's busy; however
1288          * this means there's a race between clearing the flag and setting the
1289          * work pending bit and the work item being processed again */
1290         if (call->events && !work_pending(&call->processor)) {
1291                 _debug("jumpstart %x", call->conn->proto.cid);
1292                 rxrpc_queue_call(call);
1293         }
1294
1295         _leave("");
1296         return;
1297
1298 no_mem:
1299         _debug("out of memory");
1300         goto maybe_reschedule;
1301 }