net/rxrpc/input.c

   1 /* RxRPC packet reception
   2  *
   3  * Copyright (C) 2007, 2016 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/net.h>
  16 #include <linux/skbuff.h>
  17 #include <linux/errqueue.h>
  18 #include <linux/udp.h>
  19 #include <linux/in.h>
  20 #include <linux/in6.h>
  21 #include <linux/icmp.h>
  22 #include <linux/gfp.h>
  23 #include <net/sock.h>
  24 #include <net/af_rxrpc.h>
  25 #include <net/ip.h>
  26 #include <net/udp.h>
  27 #include <net/net_namespace.h>
  28 #include "ar-internal.h"
  29
  30 static void rxrpc_proto_abort(const char *why,
  31                               struct rxrpc_call *call, rxrpc_seq_t seq)
  32 {
  33         if (rxrpc_abort_call(why, call, seq, RX_PROTOCOL_ERROR, EBADMSG)) {
  34                 set_bit(RXRPC_CALL_EV_ABORT, &call->events);
  35                 rxrpc_queue_call(call);
  36         }
  37 }
  38
  39 /*
  40  * Apply a hard ACK by advancing the Tx window.
  41  */
  42 static void rxrpc_rotate_tx_window(struct rxrpc_call *call, rxrpc_seq_t to)
  43 {
  44         struct sk_buff *skb, *list = NULL;
  45         int ix;
  46
  47         spin_lock(&call->lock);
  48
  49         while (before(call->tx_hard_ack, to)) {
  50                 call->tx_hard_ack++;
  51                 ix = call->tx_hard_ack & RXRPC_RXTX_BUFF_MASK;
  52                 skb = call->rxtx_buffer[ix];
  53                 rxrpc_see_skb(skb);
  54                 call->rxtx_buffer[ix] = NULL;
  55                 call->rxtx_annotations[ix] = 0;
  56                 skb->next = list;
  57                 list = skb;
  58         }
  59
  60         spin_unlock(&call->lock);
  61
  62         trace_rxrpc_transmit(call, rxrpc_transmit_rotate);
  63         wake_up(&call->waitq);
  64
  65         while (list) {
  66                 skb = list;
  67                 list = skb->next;
  68                 skb->next = NULL;
  69                 rxrpc_free_skb(skb);
  70         }
  71 }
  72
  73 /*
  74  * End the transmission phase of a call.
  75  *
  76  * This occurs when we get an ACKALL packet, the first DATA packet of a reply,
  77  * or a final ACK packet.
  78  */
  79 static bool rxrpc_end_tx_phase(struct rxrpc_call *call, const char *abort_why)
  80 {
  81         _enter("");
  82
  83         switch (call->state) {
  84         case RXRPC_CALL_CLIENT_RECV_REPLY:
  85                 return true;
  86         case RXRPC_CALL_CLIENT_AWAIT_REPLY:
  87         case RXRPC_CALL_SERVER_AWAIT_ACK:
  88                 break;
  89         default:
  90                 rxrpc_proto_abort(abort_why, call, call->tx_top);
  91                 return false;
  92         }
  93
  94         rxrpc_rotate_tx_window(call, call->tx_top);
  95
  96         write_lock(&call->state_lock);
  97
  98         switch (call->state) {
  99         default:
 100                 break;
 101         case RXRPC_CALL_CLIENT_AWAIT_REPLY:
 102                 call->state = RXRPC_CALL_CLIENT_RECV_REPLY;
 103                 break;
 104         case RXRPC_CALL_SERVER_AWAIT_ACK:
 105                 __rxrpc_call_completed(call);
 106                 rxrpc_notify_socket(call);
 107                 break;
 108         }
 109
 110         write_unlock(&call->state_lock);
 111         trace_rxrpc_transmit(call, rxrpc_transmit_end);
 112         _leave(" = ok");
 113         return true;
 114 }
 115
 116 /*
 117  * Scan a jumbo packet to validate its structure and to work out how many
 118  * subpackets it contains.
 119  *
 120  * A jumbo packet is a collection of consecutive packets glued together with
 121  * little headers between that indicate how to change the initial header for
 122  * each subpacket.
 123  *
 124  * RXRPC_JUMBO_PACKET must be set on all but the last subpacket - and all but
 125  * the last are RXRPC_JUMBO_DATALEN in size.  The last subpacket may be of any
 126  * size.
 127  */
 128 static bool rxrpc_validate_jumbo(struct sk_buff *skb)
 129 {
 130         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 131         unsigned int offset = sp->offset;
 132         unsigned int len = skb->len;
 133         int nr_jumbo = 1;
 134         u8 flags = sp->hdr.flags;
 135
 136         do {
 137                 nr_jumbo++;
 138                 if (len - offset < RXRPC_JUMBO_SUBPKTLEN)
 139                         goto protocol_error;
 140                 if (flags & RXRPC_LAST_PACKET)
 141                         goto protocol_error;
 142                 offset += RXRPC_JUMBO_DATALEN;
 143                 if (skb_copy_bits(skb, offset, &flags, 1) < 0)
 144                         goto protocol_error;
 145                 offset += sizeof(struct rxrpc_jumbo_header);
 146         } while (flags & RXRPC_JUMBO_PACKET);
 147
 148         sp->nr_jumbo = nr_jumbo;
 149         return true;
 150
 151 protocol_error:
 152         return false;
 153 }
 154
 155 /*
 156  * Handle reception of a duplicate packet.
 157  *
 158  * We have to take care to avoid an attack here whereby we're given a series of
 159  * jumbograms, each with a sequence number one before the preceding one and
 160  * filled up to maximum UDP size.  If they never send us the first packet in
 161  * the sequence, they can cause us to have to hold on to around 2MiB of kernel
 162  * space until the call times out.
 163  *
 164  * We limit the space usage by only accepting three duplicate jumbo packets per
 165  * call.  After that, we tell the other side we're no longer accepting jumbos
 166  * (that information is encoded in the ACK packet).
 167  */
 168 static void rxrpc_input_dup_data(struct rxrpc_call *call, rxrpc_seq_t seq,
 169                                  u8 annotation, bool *_jumbo_bad)
 170 {
 171         /* Discard normal packets that are duplicates. */
 172         if (annotation == 0)
 173                 return;
 174
 175         /* Skip jumbo subpackets that are duplicates.  When we've had three or
 176          * more partially duplicate jumbo packets, we refuse to take any more
 177          * jumbos for this call.
 178          */
 179         if (!*_jumbo_bad) {
 180                 call->nr_jumbo_bad++;
 181                 *_jumbo_bad = true;
 182         }
 183 }
 184
 185 /*
 186  * Process a DATA packet, adding the packet to the Rx ring.
 187  */
 188 static void rxrpc_input_data(struct rxrpc_call *call, struct sk_buff *skb,
 189                              u16 skew)
 190 {
 191         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 192         unsigned int offset = sp->offset;
 193         unsigned int ix;
 194         rxrpc_serial_t serial = sp->hdr.serial, ack_serial = 0;
 195         rxrpc_seq_t seq = sp->hdr.seq, hard_ack;
 196         bool immediate_ack = false, jumbo_bad = false, queued;
 197         u16 len;
 198         u8 ack = 0, flags, annotation = 0;
 199
 200         _enter("{%u,%u},{%u,%u}",
 201                call->rx_hard_ack, call->rx_top, skb->len, seq);
 202
 203         _proto("Rx DATA %%%u { #%u f=%02x }",
 204                sp->hdr.serial, seq, sp->hdr.flags);
 205
 206         if (call->state >= RXRPC_CALL_COMPLETE)
 207                 return;
 208
 209         /* Received data implicitly ACKs all of the request packets we sent
 210          * when we're acting as a client.
 211          */
 212         if (call->state == RXRPC_CALL_CLIENT_AWAIT_REPLY &&
 213             !rxrpc_end_tx_phase(call, "ETD"))
 214                 return;
 215
 216         call->ackr_prev_seq = seq;
 217
 218         hard_ack = READ_ONCE(call->rx_hard_ack);
 219         if (after(seq, hard_ack + call->rx_winsize)) {
 220                 ack = RXRPC_ACK_EXCEEDS_WINDOW;
 221                 ack_serial = serial;
 222                 goto ack;
 223         }
 224
 225         flags = sp->hdr.flags;
 226         if (flags & RXRPC_JUMBO_PACKET) {
 227                 if (call->nr_jumbo_bad > 3) {
 228                         ack = RXRPC_ACK_NOSPACE;
 229                         ack_serial = serial;
 230                         goto ack;
 231                 }
 232                 annotation = 1;
 233         }
 234
 235 next_subpacket:
 236         queued = false;
 237         ix = seq & RXRPC_RXTX_BUFF_MASK;
 238         len = skb->len;
 239         if (flags & RXRPC_JUMBO_PACKET)
 240                 len = RXRPC_JUMBO_DATALEN;
 241
 242         if (flags & RXRPC_LAST_PACKET) {
 243                 if (test_bit(RXRPC_CALL_RX_LAST, &call->flags) &&
 244                     seq != call->rx_top)
 245                         return rxrpc_proto_abort("LSN", call, seq);
 246         } else {
 247                 if (test_bit(RXRPC_CALL_RX_LAST, &call->flags) &&
 248                     after_eq(seq, call->rx_top))
 249                         return rxrpc_proto_abort("LSA", call, seq);
 250         }
 251
 252         if (before_eq(seq, hard_ack)) {
 253                 ack = RXRPC_ACK_DUPLICATE;
 254                 ack_serial = serial;
 255                 goto skip;
 256         }
 257
 258         if (flags & RXRPC_REQUEST_ACK && !ack) {
 259                 ack = RXRPC_ACK_REQUESTED;
 260                 ack_serial = serial;
 261         }
 262
 263         if (call->rxtx_buffer[ix]) {
 264                 rxrpc_input_dup_data(call, seq, annotation, &jumbo_bad);
 265                 if (ack != RXRPC_ACK_DUPLICATE) {
 266                         ack = RXRPC_ACK_DUPLICATE;
 267                         ack_serial = serial;
 268                 }
 269                 immediate_ack = true;
 270                 goto skip;
 271         }
 272
 273         /* Queue the packet.  We use a couple of memory barriers here as need
 274          * to make sure that rx_top is perceived to be set after the buffer
 275          * pointer and that the buffer pointer is set after the annotation and
 276          * the skb data.
 277          *
 278          * Barriers against rxrpc_recvmsg_data() and rxrpc_rotate_rx_window()
 279          * and also rxrpc_fill_out_ack().
 280          */
 281         rxrpc_get_skb(skb);
 282         call->rxtx_annotations[ix] = annotation;
 283         smp_wmb();
 284         call->rxtx_buffer[ix] = skb;
 285         if (after(seq, call->rx_top))
 286                 smp_store_release(&call->rx_top, seq);
 287         if (flags & RXRPC_LAST_PACKET) {
 288                 set_bit(RXRPC_CALL_RX_LAST, &call->flags);
 289                 trace_rxrpc_receive(call, rxrpc_receive_queue_last, serial, seq);
 290         } else {
 291                 trace_rxrpc_receive(call, rxrpc_receive_queue, serial, seq);
 292         }
 293         queued = true;
 294
 295         if (after_eq(seq, call->rx_expect_next)) {
 296                 if (after(seq, call->rx_expect_next)) {
 297                         _net("OOS %u > %u", seq, call->rx_expect_next);
 298                         ack = RXRPC_ACK_OUT_OF_SEQUENCE;
 299                         ack_serial = serial;
 300                 }
 301                 call->rx_expect_next = seq + 1;
 302         }
 303
 304 skip:
 305         offset += len;
 306         if (flags & RXRPC_JUMBO_PACKET) {
 307                 if (skb_copy_bits(skb, offset, &flags, 1) < 0)
 308                         return rxrpc_proto_abort("XJF", call, seq);
 309                 offset += sizeof(struct rxrpc_jumbo_header);
 310                 seq++;
 311                 serial++;
 312                 annotation++;
 313                 if (flags & RXRPC_JUMBO_PACKET)
 314                         annotation |= RXRPC_RX_ANNO_JLAST;
 315                 if (after(seq, hard_ack + call->rx_winsize)) {
 316                         ack = RXRPC_ACK_EXCEEDS_WINDOW;
 317                         ack_serial = serial;
 318                         if (!jumbo_bad) {
 319                                 call->nr_jumbo_bad++;
 320                                 jumbo_bad = true;
 321                         }
 322                         goto ack;
 323                 }
 324
 325                 _proto("Rx DATA Jumbo %%%u", serial);
 326                 goto next_subpacket;
 327         }
 328
 329         if (queued && flags & RXRPC_LAST_PACKET && !ack) {
 330                 ack = RXRPC_ACK_DELAY;
 331                 ack_serial = serial;
 332         }
 333
 334 ack:
 335         if (ack)
 336                 rxrpc_propose_ACK(call, ack, skew, ack_serial,
 337                                   immediate_ack, true);
 338
 339         if (sp->hdr.seq == READ_ONCE(call->rx_hard_ack) + 1)
 340                 rxrpc_notify_socket(call);
 341         _leave(" [queued]");
 342 }
 343
 344 /*
 345  * Process the extra information that may be appended to an ACK packet
 346  */
 347 static void rxrpc_input_ackinfo(struct rxrpc_call *call, struct sk_buff *skb,
 348                                 struct rxrpc_ackinfo *ackinfo)
 349 {
 350         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 351         struct rxrpc_peer *peer;
 352         unsigned int mtu;
 353         u32 rwind = ntohl(ackinfo->rwind);
 354
 355         _proto("Rx ACK %%%u Info { rx=%u max=%u rwin=%u jm=%u }",
 356                sp->hdr.serial,
 357                ntohl(ackinfo->rxMTU), ntohl(ackinfo->maxMTU),
 358                rwind, ntohl(ackinfo->jumbo_max));
 359
 360         if (rwind > RXRPC_RXTX_BUFF_SIZE - 1)
 361                 rwind = RXRPC_RXTX_BUFF_SIZE - 1;
 362         call->tx_winsize = rwind;
 363
 364         mtu = min(ntohl(ackinfo->rxMTU), ntohl(ackinfo->maxMTU));
 365
 366         peer = call->peer;
 367         if (mtu < peer->maxdata) {
 368                 spin_lock_bh(&peer->lock);
 369                 peer->maxdata = mtu;
 370                 peer->mtu = mtu + peer->hdrsize;
 371                 spin_unlock_bh(&peer->lock);
 372                 _net("Net MTU %u (maxdata %u)", peer->mtu, peer->maxdata);
 373         }
 374 }
 375
 376 /*
 377  * Process individual soft ACKs.
 378  *
 379  * Each ACK in the array corresponds to one packet and can be either an ACK or
 380  * a NAK.  If we get find an explicitly NAK'd packet we resend immediately;
 381  * packets that lie beyond the end of the ACK list are scheduled for resend by
 382  * the timer on the basis that the peer might just not have processed them at
 383  * the time the ACK was sent.
 384  */
 385 static void rxrpc_input_soft_acks(struct rxrpc_call *call, u8 *acks,
 386                                   rxrpc_seq_t seq, int nr_acks)
 387 {
 388         bool resend = false;
 389         int ix;
 390
 391         for (; nr_acks > 0; nr_acks--, seq++) {
 392                 ix = seq & RXRPC_RXTX_BUFF_MASK;
 393                 switch (*acks++) {
 394                 case RXRPC_ACK_TYPE_ACK:
 395                         call->rxtx_annotations[ix] = RXRPC_TX_ANNO_ACK;
 396                         break;
 397                 case RXRPC_ACK_TYPE_NACK:
 398                         if (call->rxtx_annotations[ix] == RXRPC_TX_ANNO_NAK)
 399                                 continue;
 400                         call->rxtx_annotations[ix] = RXRPC_TX_ANNO_NAK;
 401                         resend = true;
 402                         break;
 403                 default:
 404                         return rxrpc_proto_abort("SFT", call, 0);
 405                 }
 406         }
 407
 408         if (resend &&
 409             !test_and_set_bit(RXRPC_CALL_EV_RESEND, &call->events))
 410                 rxrpc_queue_call(call);
 411 }
 412
 413 /*
 414  * Process an ACK packet.
 415  *
 416  * ack.firstPacket is the sequence number of the first soft-ACK'd/NAK'd packet
 417  * in the ACK array.  Anything before that is hard-ACK'd and may be discarded.
 418  *
 419  * A hard-ACK means that a packet has been processed and may be discarded; a
 420  * soft-ACK means that the packet may be discarded and retransmission
 421  * requested.  A phase is complete when all packets are hard-ACK'd.
 422  */
 423 static void rxrpc_input_ack(struct rxrpc_call *call, struct sk_buff *skb,
 424                             u16 skew)
 425 {
 426         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 427         union {
 428                 struct rxrpc_ackpacket ack;
 429                 struct rxrpc_ackinfo info;
 430                 u8 acks[RXRPC_MAXACKS];
 431         } buf;
 432         rxrpc_seq_t first_soft_ack, hard_ack;
 433         int nr_acks, offset;
 434
 435         _enter("");
 436
 437         if (skb_copy_bits(skb, sp->offset, &buf.ack, sizeof(buf.ack)) < 0) {
 438                 _debug("extraction failure");
 439                 return rxrpc_proto_abort("XAK", call, 0);
 440         }
 441         sp->offset += sizeof(buf.ack);
 442
 443         first_soft_ack = ntohl(buf.ack.firstPacket);
 444         hard_ack = first_soft_ack - 1;
 445         nr_acks = buf.ack.nAcks;
 446
 447         trace_rxrpc_rx_ack(call, first_soft_ack, buf.ack.reason, nr_acks);
 448
 449         _proto("Rx ACK %%%u { m=%hu f=#%u p=#%u s=%%%u r=%s n=%u }",
 450                sp->hdr.serial,
 451                ntohs(buf.ack.maxSkew),
 452                first_soft_ack,
 453                ntohl(buf.ack.previousPacket),
 454                ntohl(buf.ack.serial),
 455                rxrpc_acks(buf.ack.reason),
 456                buf.ack.nAcks);
 457
 458         if (buf.ack.reason == RXRPC_ACK_PING) {
 459                 _proto("Rx ACK %%%u PING Request", sp->hdr.serial);
 460                 rxrpc_propose_ACK(call, RXRPC_ACK_PING_RESPONSE,
 461                                   skew, sp->hdr.serial, true, true);
 462         } else if (sp->hdr.flags & RXRPC_REQUEST_ACK) {
 463                 rxrpc_propose_ACK(call, RXRPC_ACK_REQUESTED,
 464                                   skew, sp->hdr.serial, true, true);
 465         }
 466
 467         offset = sp->offset + nr_acks + 3;
 468         if (skb->len >= offset + sizeof(buf.info)) {
 469                 if (skb_copy_bits(skb, offset, &buf.info, sizeof(buf.info)) < 0)
 470                         return rxrpc_proto_abort("XAI", call, 0);
 471                 rxrpc_input_ackinfo(call, skb, &buf.info);
 472         }
 473
 474         if (first_soft_ack == 0)
 475                 return rxrpc_proto_abort("AK0", call, 0);
 476
 477         /* Ignore ACKs unless we are or have just been transmitting. */
 478         switch (call->state) {
 479         case RXRPC_CALL_CLIENT_SEND_REQUEST:
 480         case RXRPC_CALL_CLIENT_AWAIT_REPLY:
 481         case RXRPC_CALL_SERVER_SEND_REPLY:
 482         case RXRPC_CALL_SERVER_AWAIT_ACK:
 483                 break;
 484         default:
 485                 return;
 486         }
 487
 488         /* Discard any out-of-order or duplicate ACKs. */
 489         if ((int)sp->hdr.serial - (int)call->acks_latest <= 0) {
 490                 _debug("discard ACK %d <= %d",
 491                        sp->hdr.serial, call->acks_latest);
 492                 return;
 493         }
 494         call->acks_latest = sp->hdr.serial;
 495
 496         if (test_bit(RXRPC_CALL_TX_LAST, &call->flags) &&
 497             hard_ack == call->tx_top) {
 498                 rxrpc_end_tx_phase(call, "ETA");
 499                 return;
 500         }
 501
 502         if (before(hard_ack, call->tx_hard_ack) ||
 503             after(hard_ack, call->tx_top))
 504                 return rxrpc_proto_abort("AKW", call, 0);
 505
 506         if (after(hard_ack, call->tx_hard_ack))
 507                 rxrpc_rotate_tx_window(call, hard_ack);
 508
 509         if (after(first_soft_ack, call->tx_top))
 510                 return;
 511
 512         if (nr_acks > call->tx_top - first_soft_ack + 1)
 513                 nr_acks = first_soft_ack - call->tx_top + 1;
 514         if (skb_copy_bits(skb, sp->offset, buf.acks, nr_acks) < 0)
 515                 return rxrpc_proto_abort("XSA", call, 0);
 516         rxrpc_input_soft_acks(call, buf.acks, first_soft_ack, nr_acks);
 517 }
 518
 519 /*
 520  * Process an ACKALL packet.
 521  */
 522 static void rxrpc_input_ackall(struct rxrpc_call *call, struct sk_buff *skb)
 523 {
 524         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 525
 526         _proto("Rx ACKALL %%%u", sp->hdr.serial);
 527
 528         rxrpc_end_tx_phase(call, "ETL");
 529 }
 530
 531 /*
 532  * Process an ABORT packet.
 533  */
 534 static void rxrpc_input_abort(struct rxrpc_call *call, struct sk_buff *skb)
 535 {
 536         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 537         __be32 wtmp;
 538         u32 abort_code = RX_CALL_DEAD;
 539
 540         _enter("");
 541
 542         if (skb->len >= 4 &&
 543             skb_copy_bits(skb, sp->offset, &wtmp, sizeof(wtmp)) >= 0)
 544                 abort_code = ntohl(wtmp);
 545
 546         _proto("Rx ABORT %%%u { %x }", sp->hdr.serial, abort_code);
 547
 548         if (rxrpc_set_call_completion(call, RXRPC_CALL_REMOTELY_ABORTED,
 549                                       abort_code, ECONNABORTED))
 550                 rxrpc_notify_socket(call);
 551 }
 552
 553 /*
 554  * Process an incoming call packet.
 555  */
 556 static void rxrpc_input_call_packet(struct rxrpc_call *call,
 557                                     struct sk_buff *skb, u16 skew)
 558 {
 559         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 560
 561         _enter("%p,%p", call, skb);
 562
 563         switch (sp->hdr.type) {
 564         case RXRPC_PACKET_TYPE_DATA:
 565                 rxrpc_input_data(call, skb, skew);
 566                 break;
 567
 568         case RXRPC_PACKET_TYPE_ACK:
 569                 rxrpc_input_ack(call, skb, skew);
 570                 break;
 571
 572         case RXRPC_PACKET_TYPE_BUSY:
 573                 _proto("Rx BUSY %%%u", sp->hdr.serial);
 574
 575                 /* Just ignore BUSY packets from the server; the retry and
 576                  * lifespan timers will take care of business.  BUSY packets
 577                  * from the client don't make sense.
 578                  */
 579                 break;
 580
 581         case RXRPC_PACKET_TYPE_ABORT:
 582                 rxrpc_input_abort(call, skb);
 583                 break;
 584
 585         case RXRPC_PACKET_TYPE_ACKALL:
 586                 rxrpc_input_ackall(call, skb);
 587                 break;
 588
 589         default:
 590                 _proto("Rx %s %%%u", rxrpc_pkts[sp->hdr.type], sp->hdr.serial);
 591                 break;
 592         }
 593
 594         _leave("");
 595 }
 596
 597 /*
 598  * post connection-level events to the connection
 599  * - this includes challenges, responses, some aborts and call terminal packet
 600  *   retransmission.
 601  */
 602 static void rxrpc_post_packet_to_conn(struct rxrpc_connection *conn,
 603                                       struct sk_buff *skb)
 604 {
 605         _enter("%p,%p", conn, skb);
 606
 607         skb_queue_tail(&conn->rx_queue, skb);
 608         rxrpc_queue_conn(conn);
 609 }
 610
 611 /*
 612  * post endpoint-level events to the local endpoint
 613  * - this includes debug and version messages
 614  */
 615 static void rxrpc_post_packet_to_local(struct rxrpc_local *local,
 616                                        struct sk_buff *skb)
 617 {
 618         _enter("%p,%p", local, skb);
 619
 620         skb_queue_tail(&local->event_queue, skb);
 621         rxrpc_queue_local(local);
 622 }
 623
 624 /*
 625  * put a packet up for transport-level abort
 626  */
 627 static void rxrpc_reject_packet(struct rxrpc_local *local, struct sk_buff *skb)
 628 {
 629         CHECK_SLAB_OKAY(&local->usage);
 630
 631         skb_queue_tail(&local->reject_queue, skb);
 632         rxrpc_queue_local(local);
 633 }
 634
 635 /*
 636  * Extract the wire header from a packet and translate the byte order.
 637  */
 638 static noinline
 639 int rxrpc_extract_header(struct rxrpc_skb_priv *sp, struct sk_buff *skb)
 640 {
 641         struct rxrpc_wire_header whdr;
 642
 643         /* dig out the RxRPC connection details */
 644         if (skb_copy_bits(skb, 0, &whdr, sizeof(whdr)) < 0)
 645                 return -EBADMSG;
 646
 647         memset(sp, 0, sizeof(*sp));
 648         sp->hdr.epoch           = ntohl(whdr.epoch);
 649         sp->hdr.cid             = ntohl(whdr.cid);
 650         sp->hdr.callNumber      = ntohl(whdr.callNumber);
 651         sp->hdr.seq             = ntohl(whdr.seq);
 652         sp->hdr.serial          = ntohl(whdr.serial);
 653         sp->hdr.flags           = whdr.flags;
 654         sp->hdr.type            = whdr.type;
 655         sp->hdr.userStatus      = whdr.userStatus;
 656         sp->hdr.securityIndex   = whdr.securityIndex;
 657         sp->hdr._rsvd           = ntohs(whdr._rsvd);
 658         sp->hdr.serviceId       = ntohs(whdr.serviceId);
 659         sp->offset = sizeof(whdr);
 660         return 0;
 661 }
 662
 663 /*
 664  * handle data received on the local endpoint
 665  * - may be called in interrupt context
 666  *
 667  * The socket is locked by the caller and this prevents the socket from being
 668  * shut down and the local endpoint from going away, thus sk_user_data will not
 669  * be cleared until this function returns.
 670  */
 671 void rxrpc_data_ready(struct sock *udp_sk)
 672 {
 673         struct rxrpc_connection *conn;
 674         struct rxrpc_channel *chan;
 675         struct rxrpc_call *call;
 676         struct rxrpc_skb_priv *sp;
 677         struct rxrpc_local *local = udp_sk->sk_user_data;
 678         struct sk_buff *skb;
 679         unsigned int channel;
 680         int ret, skew;
 681
 682         _enter("%p", udp_sk);
 683
 684         ASSERT(!irqs_disabled());
 685
 686         skb = skb_recv_datagram(udp_sk, 0, 1, &ret);
 687         if (!skb) {
 688                 if (ret == -EAGAIN)
 689                         return;
 690                 _debug("UDP socket error %d", ret);
 691                 return;
 692         }
 693
 694         rxrpc_new_skb(skb);
 695
 696         _net("recv skb %p", skb);
 697
 698         /* we'll probably need to checksum it (didn't call sock_recvmsg) */
 699         if (skb_checksum_complete(skb)) {
 700                 rxrpc_free_skb(skb);
 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         trace_rxrpc_rx_packet(sp);
 721
 722         _net("Rx RxRPC %s ep=%x call=%x:%x",
 723              sp->hdr.flags & RXRPC_CLIENT_INITIATED ? "ToServer" : "ToClient",
 724              sp->hdr.epoch, sp->hdr.cid, sp->hdr.callNumber);
 725
 726         if (sp->hdr.type >= RXRPC_N_PACKET_TYPES ||
 727             !((RXRPC_SUPPORTED_PACKET_TYPES >> sp->hdr.type) & 1)) {
 728                 _proto("Rx Bad Packet Type %u", sp->hdr.type);
 729                 goto bad_message;
 730         }
 731
 732         switch (sp->hdr.type) {
 733         case RXRPC_PACKET_TYPE_VERSION:
 734                 rxrpc_post_packet_to_local(local, skb);
 735                 goto out;
 736
 737         case RXRPC_PACKET_TYPE_BUSY:
 738                 if (sp->hdr.flags & RXRPC_CLIENT_INITIATED)
 739                         goto discard;
 740
 741         case RXRPC_PACKET_TYPE_DATA:
 742                 if (sp->hdr.callNumber == 0)
 743                         goto bad_message;
 744                 if (sp->hdr.flags & RXRPC_JUMBO_PACKET &&
 745                     !rxrpc_validate_jumbo(skb))
 746                         goto bad_message;
 747                 break;
 748         }
 749
 750         rcu_read_lock();
 751
 752         conn = rxrpc_find_connection_rcu(local, skb);
 753         if (conn) {
 754                 if (sp->hdr.securityIndex != conn->security_ix)
 755                         goto wrong_security;
 756
 757                 if (sp->hdr.callNumber == 0) {
 758                         /* Connection-level packet */
 759                         _debug("CONN %p {%d}", conn, conn->debug_id);
 760                         rxrpc_post_packet_to_conn(conn, skb);
 761                         goto out_unlock;
 762                 }
 763
 764                 /* Note the serial number skew here */
 765                 skew = (int)sp->hdr.serial - (int)conn->hi_serial;
 766                 if (skew >= 0) {
 767                         if (skew > 0)
 768                                 conn->hi_serial = sp->hdr.serial;
 769                 } else {
 770                         skew = -skew;
 771                         skew = min(skew, 65535);
 772                 }
 773
 774                 /* Call-bound packets are routed by connection channel. */
 775                 channel = sp->hdr.cid & RXRPC_CHANNELMASK;
 776                 chan = &conn->channels[channel];
 777
 778                 /* Ignore really old calls */
 779                 if (sp->hdr.callNumber < chan->last_call)
 780                         goto discard_unlock;
 781
 782                 if (sp->hdr.callNumber == chan->last_call) {
 783                         /* For the previous service call, if completed successfully, we
 784                          * discard all further packets.
 785                          */
 786                         if (rxrpc_conn_is_service(conn) &&
 787                             (chan->last_type == RXRPC_PACKET_TYPE_ACK ||
 788                              sp->hdr.type == RXRPC_PACKET_TYPE_ABORT))
 789                                 goto discard_unlock;
 790
 791                         /* But otherwise we need to retransmit the final packet from
 792                          * data cached in the connection record.
 793                          */
 794                         rxrpc_post_packet_to_conn(conn, skb);
 795                         goto out_unlock;
 796                 }
 797
 798                 call = rcu_dereference(chan->call);
 799         } else {
 800                 skew = 0;
 801                 call = NULL;
 802         }
 803
 804         if (!call || atomic_read(&call->usage) == 0) {
 805                 if (!(sp->hdr.type & RXRPC_CLIENT_INITIATED) ||
 806                     sp->hdr.callNumber == 0 ||
 807                     sp->hdr.type != RXRPC_PACKET_TYPE_DATA)
 808                         goto bad_message_unlock;
 809                 if (sp->hdr.seq != 1)
 810                         goto discard_unlock;
 811                 call = rxrpc_new_incoming_call(local, conn, skb);
 812                 if (!call) {
 813                         rcu_read_unlock();
 814                         goto reject_packet;
 815                 }
 816         }
 817
 818         rxrpc_input_call_packet(call, skb, skew);
 819         goto discard_unlock;
 820
 821 discard_unlock:
 822         rcu_read_unlock();
 823 discard:
 824         rxrpc_free_skb(skb);
 825 out:
 826         trace_rxrpc_rx_done(0, 0);
 827         return;
 828
 829 out_unlock:
 830         rcu_read_unlock();
 831         goto out;
 832
 833 wrong_security:
 834         rcu_read_unlock();
 835         trace_rxrpc_abort("SEC", sp->hdr.cid, sp->hdr.callNumber, sp->hdr.seq,
 836                           RXKADINCONSISTENCY, EBADMSG);
 837         skb->priority = RXKADINCONSISTENCY;
 838         goto post_abort;
 839
 840 bad_message_unlock:
 841         rcu_read_unlock();
 842 bad_message:
 843         trace_rxrpc_abort("BAD", sp->hdr.cid, sp->hdr.callNumber, sp->hdr.seq,
 844                           RX_PROTOCOL_ERROR, EBADMSG);
 845         skb->priority = RX_PROTOCOL_ERROR;
 846 post_abort:
 847         skb->mark = RXRPC_SKB_MARK_LOCAL_ABORT;
 848 reject_packet:
 849         trace_rxrpc_rx_done(skb->mark, skb->priority);
 850         rxrpc_reject_packet(local, skb);
 851         _leave(" [badmsg]");
 852 }