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         wake_up(&call->waitq);
  63
  64         while (list) {
  65                 skb = list;
  66                 list = skb->next;
  67                 skb->next = NULL;
  68                 rxrpc_free_skb(skb);
  69         }
  70 }
  71
  72 /*
  73  * End the transmission phase of a call.
  74  *
  75  * This occurs when we get an ACKALL packet, the first DATA packet of a reply,
  76  * or a final ACK packet.
  77  */
  78 static bool rxrpc_end_tx_phase(struct rxrpc_call *call, const char *abort_why)
  79 {
  80         _enter("");
  81
  82         switch (call->state) {
  83         case RXRPC_CALL_CLIENT_RECV_REPLY:
  84                 return true;
  85         case RXRPC_CALL_CLIENT_AWAIT_REPLY:
  86         case RXRPC_CALL_SERVER_AWAIT_ACK:
  87                 break;
  88         default:
  89                 rxrpc_proto_abort(abort_why, call, call->tx_top);
  90                 return false;
  91         }
  92
  93         rxrpc_rotate_tx_window(call, call->tx_top);
  94
  95         write_lock(&call->state_lock);
  96
  97         switch (call->state) {
  98         default:
  99                 break;
 100         case RXRPC_CALL_CLIENT_AWAIT_REPLY:
 101                 call->state = RXRPC_CALL_CLIENT_RECV_REPLY;
 102                 break;
 103         case RXRPC_CALL_SERVER_AWAIT_ACK:
 104                 __rxrpc_call_completed(call);
 105                 rxrpc_notify_socket(call);
 106                 break;
 107         }
 108
 109         write_unlock(&call->state_lock);
 110         _leave(" = ok");
 111         return true;
 112 }
 113
 114 /*
 115  * Scan a jumbo packet to validate its structure and to work out how many
 116  * subpackets it contains.
 117  *
 118  * A jumbo packet is a collection of consecutive packets glued together with
 119  * little headers between that indicate how to change the initial header for
 120  * each subpacket.
 121  *
 122  * RXRPC_JUMBO_PACKET must be set on all but the last subpacket - and all but
 123  * the last are RXRPC_JUMBO_DATALEN in size.  The last subpacket may be of any
 124  * size.
 125  */
 126 static bool rxrpc_validate_jumbo(struct sk_buff *skb)
 127 {
 128         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 129         unsigned int offset = sp->offset;
 130         unsigned int len = skb->len;
 131         int nr_jumbo = 1;
 132         u8 flags = sp->hdr.flags;
 133
 134         do {
 135                 nr_jumbo++;
 136                 if (len - offset < RXRPC_JUMBO_SUBPKTLEN)
 137                         goto protocol_error;
 138                 if (flags & RXRPC_LAST_PACKET)
 139                         goto protocol_error;
 140                 offset += RXRPC_JUMBO_DATALEN;
 141                 if (skb_copy_bits(skb, offset, &flags, 1) < 0)
 142                         goto protocol_error;
 143                 offset += sizeof(struct rxrpc_jumbo_header);
 144         } while (flags & RXRPC_JUMBO_PACKET);
 145
 146         sp->nr_jumbo = nr_jumbo;
 147         return true;
 148
 149 protocol_error:
 150         return false;
 151 }
 152
 153 /*
 154  * Handle reception of a duplicate packet.
 155  *
 156  * We have to take care to avoid an attack here whereby we're given a series of
 157  * jumbograms, each with a sequence number one before the preceding one and
 158  * filled up to maximum UDP size.  If they never send us the first packet in
 159  * the sequence, they can cause us to have to hold on to around 2MiB of kernel
 160  * space until the call times out.
 161  *
 162  * We limit the space usage by only accepting three duplicate jumbo packets per
 163  * call.  After that, we tell the other side we're no longer accepting jumbos
 164  * (that information is encoded in the ACK packet).
 165  */
 166 static void rxrpc_input_dup_data(struct rxrpc_call *call, rxrpc_seq_t seq,
 167                                  u8 annotation, bool *_jumbo_bad)
 168 {
 169         /* Discard normal packets that are duplicates. */
 170         if (annotation == 0)
 171                 return;
 172
 173         /* Skip jumbo subpackets that are duplicates.  When we've had three or
 174          * more partially duplicate jumbo packets, we refuse to take any more
 175          * jumbos for this call.
 176          */
 177         if (!*_jumbo_bad) {
 178                 call->nr_jumbo_bad++;
 179                 *_jumbo_bad = true;
 180         }
 181 }
 182
 183 /*
 184  * Process a DATA packet, adding the packet to the Rx ring.
 185  */
 186 static void rxrpc_input_data(struct rxrpc_call *call, struct sk_buff *skb,
 187                              u16 skew)
 188 {
 189         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 190         unsigned int offset = sp->offset;
 191         unsigned int ix;
 192         rxrpc_serial_t serial = sp->hdr.serial, ack_serial = 0;
 193         rxrpc_seq_t seq = sp->hdr.seq, hard_ack;
 194         bool immediate_ack = false, jumbo_bad = false, queued;
 195         u16 len;
 196         u8 ack = 0, flags, annotation = 0;
 197
 198         _enter("{%u,%u},{%u,%u}",
 199                call->rx_hard_ack, call->rx_top, skb->len, seq);
 200
 201         _proto("Rx DATA %%%u { #%u f=%02x }",
 202                sp->hdr.serial, seq, sp->hdr.flags);
 203
 204         if (call->state >= RXRPC_CALL_COMPLETE)
 205                 return;
 206
 207         /* Received data implicitly ACKs all of the request packets we sent
 208          * when we're acting as a client.
 209          */
 210         if (call->state == RXRPC_CALL_CLIENT_AWAIT_REPLY &&
 211             !rxrpc_end_tx_phase(call, "ETD"))
 212                 return;
 213
 214         call->ackr_prev_seq = seq;
 215
 216         hard_ack = READ_ONCE(call->rx_hard_ack);
 217         if (after(seq, hard_ack + call->rx_winsize)) {
 218                 ack = RXRPC_ACK_EXCEEDS_WINDOW;
 219                 ack_serial = serial;
 220                 goto ack;
 221         }
 222
 223         flags = sp->hdr.flags;
 224         if (flags & RXRPC_JUMBO_PACKET) {
 225                 if (call->nr_jumbo_bad > 3) {
 226                         ack = RXRPC_ACK_NOSPACE;
 227                         ack_serial = serial;
 228                         goto ack;
 229                 }
 230                 annotation = 1;
 231         }
 232
 233 next_subpacket:
 234         queued = false;
 235         ix = seq & RXRPC_RXTX_BUFF_MASK;
 236         len = skb->len;
 237         if (flags & RXRPC_JUMBO_PACKET)
 238                 len = RXRPC_JUMBO_DATALEN;
 239
 240         if (flags & RXRPC_LAST_PACKET) {
 241                 if (test_bit(RXRPC_CALL_RX_LAST, &call->flags) &&
 242                     seq != call->rx_top)
 243                         return rxrpc_proto_abort("LSN", call, seq);
 244         } else {
 245                 if (test_bit(RXRPC_CALL_RX_LAST, &call->flags) &&
 246                     after_eq(seq, call->rx_top))
 247                         return rxrpc_proto_abort("LSA", call, seq);
 248         }
 249
 250         if (before_eq(seq, hard_ack)) {
 251                 ack = RXRPC_ACK_DUPLICATE;
 252                 ack_serial = serial;
 253                 goto skip;
 254         }
 255
 256         if (flags & RXRPC_REQUEST_ACK && !ack) {
 257                 ack = RXRPC_ACK_REQUESTED;
 258                 ack_serial = serial;
 259         }
 260
 261         if (call->rxtx_buffer[ix]) {
 262                 rxrpc_input_dup_data(call, seq, annotation, &jumbo_bad);
 263                 if (ack != RXRPC_ACK_DUPLICATE) {
 264                         ack = RXRPC_ACK_DUPLICATE;
 265                         ack_serial = serial;
 266                 }
 267                 immediate_ack = true;
 268                 goto skip;
 269         }
 270
 271         /* Queue the packet.  We use a couple of memory barriers here as need
 272          * to make sure that rx_top is perceived to be set after the buffer
 273          * pointer and that the buffer pointer is set after the annotation and
 274          * the skb data.
 275          *
 276          * Barriers against rxrpc_recvmsg_data() and rxrpc_rotate_rx_window()
 277          * and also rxrpc_fill_out_ack().
 278          */
 279         rxrpc_get_skb(skb);
 280         call->rxtx_annotations[ix] = annotation;
 281         smp_wmb();
 282         call->rxtx_buffer[ix] = skb;
 283         if (after(seq, call->rx_top))
 284                 smp_store_release(&call->rx_top, seq);
 285         if (flags & RXRPC_LAST_PACKET)
 286                 set_bit(RXRPC_CALL_RX_LAST, &call->flags);
 287         queued = true;
 288
 289         if (after_eq(seq, call->rx_expect_next)) {
 290                 if (after(seq, call->rx_expect_next)) {
 291                         _net("OOS %u > %u", seq, call->rx_expect_next);
 292                         ack = RXRPC_ACK_OUT_OF_SEQUENCE;
 293                         ack_serial = serial;
 294                 }
 295                 call->rx_expect_next = seq + 1;
 296         }
 297
 298 skip:
 299         offset += len;
 300         if (flags & RXRPC_JUMBO_PACKET) {
 301                 if (skb_copy_bits(skb, offset, &flags, 1) < 0)
 302                         return rxrpc_proto_abort("XJF", call, seq);
 303                 offset += sizeof(struct rxrpc_jumbo_header);
 304                 seq++;
 305                 serial++;
 306                 annotation++;
 307                 if (flags & RXRPC_JUMBO_PACKET)
 308                         annotation |= RXRPC_RX_ANNO_JLAST;
 309                 if (after(seq, hard_ack + call->rx_winsize)) {
 310                         ack = RXRPC_ACK_EXCEEDS_WINDOW;
 311                         ack_serial = serial;
 312                         if (!jumbo_bad) {
 313                                 call->nr_jumbo_bad++;
 314                                 jumbo_bad = true;
 315                         }
 316                         goto ack;
 317                 }
 318
 319                 _proto("Rx DATA Jumbo %%%u", serial);
 320                 goto next_subpacket;
 321         }
 322
 323         if (queued && flags & RXRPC_LAST_PACKET && !ack) {
 324                 ack = RXRPC_ACK_DELAY;
 325                 ack_serial = serial;
 326         }
 327
 328 ack:
 329         if (ack)
 330                 rxrpc_propose_ACK(call, ack, skew, ack_serial,
 331                                   immediate_ack, true);
 332
 333         if (sp->hdr.seq == READ_ONCE(call->rx_hard_ack) + 1)
 334                 rxrpc_notify_socket(call);
 335         _leave(" [queued]");
 336 }
 337
 338 /*
 339  * Process the extra information that may be appended to an ACK packet
 340  */
 341 static void rxrpc_input_ackinfo(struct rxrpc_call *call, struct sk_buff *skb,
 342                                 struct rxrpc_ackinfo *ackinfo)
 343 {
 344         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 345         struct rxrpc_peer *peer;
 346         unsigned int mtu;
 347         u32 rwind = ntohl(ackinfo->rwind);
 348
 349         _proto("Rx ACK %%%u Info { rx=%u max=%u rwin=%u jm=%u }",
 350                sp->hdr.serial,
 351                ntohl(ackinfo->rxMTU), ntohl(ackinfo->maxMTU),
 352                rwind, ntohl(ackinfo->jumbo_max));
 353
 354         if (rwind > RXRPC_RXTX_BUFF_SIZE - 1)
 355                 rwind = RXRPC_RXTX_BUFF_SIZE - 1;
 356         call->tx_winsize = rwind;
 357
 358         mtu = min(ntohl(ackinfo->rxMTU), ntohl(ackinfo->maxMTU));
 359
 360         peer = call->peer;
 361         if (mtu < peer->maxdata) {
 362                 spin_lock_bh(&peer->lock);
 363                 peer->maxdata = mtu;
 364                 peer->mtu = mtu + peer->hdrsize;
 365                 spin_unlock_bh(&peer->lock);
 366                 _net("Net MTU %u (maxdata %u)", peer->mtu, peer->maxdata);
 367         }
 368 }
 369
 370 /*
 371  * Process individual soft ACKs.
 372  *
 373  * Each ACK in the array corresponds to one packet and can be either an ACK or
 374  * a NAK.  If we get find an explicitly NAK'd packet we resend immediately;
 375  * packets that lie beyond the end of the ACK list are scheduled for resend by
 376  * the timer on the basis that the peer might just not have processed them at
 377  * the time the ACK was sent.
 378  */
 379 static void rxrpc_input_soft_acks(struct rxrpc_call *call, u8 *acks,
 380                                   rxrpc_seq_t seq, int nr_acks)
 381 {
 382         bool resend = false;
 383         int ix;
 384
 385         for (; nr_acks > 0; nr_acks--, seq++) {
 386                 ix = seq & RXRPC_RXTX_BUFF_MASK;
 387                 switch (*acks++) {
 388                 case RXRPC_ACK_TYPE_ACK:
 389                         call->rxtx_annotations[ix] = RXRPC_TX_ANNO_ACK;
 390                         break;
 391                 case RXRPC_ACK_TYPE_NACK:
 392                         if (call->rxtx_annotations[ix] == RXRPC_TX_ANNO_NAK)
 393                                 continue;
 394                         call->rxtx_annotations[ix] = RXRPC_TX_ANNO_NAK;
 395                         resend = true;
 396                         break;
 397                 default:
 398                         return rxrpc_proto_abort("SFT", call, 0);
 399                 }
 400         }
 401
 402         if (resend &&
 403             !test_and_set_bit(RXRPC_CALL_EV_RESEND, &call->events))
 404                 rxrpc_queue_call(call);
 405 }
 406
 407 /*
 408  * Process an ACK packet.
 409  *
 410  * ack.firstPacket is the sequence number of the first soft-ACK'd/NAK'd packet
 411  * in the ACK array.  Anything before that is hard-ACK'd and may be discarded.
 412  *
 413  * A hard-ACK means that a packet has been processed and may be discarded; a
 414  * soft-ACK means that the packet may be discarded and retransmission
 415  * requested.  A phase is complete when all packets are hard-ACK'd.
 416  */
 417 static void rxrpc_input_ack(struct rxrpc_call *call, struct sk_buff *skb,
 418                             u16 skew)
 419 {
 420         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 421         union {
 422                 struct rxrpc_ackpacket ack;
 423                 struct rxrpc_ackinfo info;
 424                 u8 acks[RXRPC_MAXACKS];
 425         } buf;
 426         rxrpc_seq_t first_soft_ack, hard_ack;
 427         int nr_acks, offset;
 428
 429         _enter("");
 430
 431         if (skb_copy_bits(skb, sp->offset, &buf.ack, sizeof(buf.ack)) < 0) {
 432                 _debug("extraction failure");
 433                 return rxrpc_proto_abort("XAK", call, 0);
 434         }
 435         sp->offset += sizeof(buf.ack);
 436
 437         first_soft_ack = ntohl(buf.ack.firstPacket);
 438         hard_ack = first_soft_ack - 1;
 439         nr_acks = buf.ack.nAcks;
 440
 441         _proto("Rx ACK %%%u { m=%hu f=#%u p=#%u s=%%%u r=%s n=%u }",
 442                sp->hdr.serial,
 443                ntohs(buf.ack.maxSkew),
 444                first_soft_ack,
 445                ntohl(buf.ack.previousPacket),
 446                ntohl(buf.ack.serial),
 447                rxrpc_acks(buf.ack.reason),
 448                buf.ack.nAcks);
 449
 450         if (buf.ack.reason == RXRPC_ACK_PING) {
 451                 _proto("Rx ACK %%%u PING Request", sp->hdr.serial);
 452                 rxrpc_propose_ACK(call, RXRPC_ACK_PING_RESPONSE,
 453                                   skew, sp->hdr.serial, true, true);
 454         } else if (sp->hdr.flags & RXRPC_REQUEST_ACK) {
 455                 rxrpc_propose_ACK(call, RXRPC_ACK_REQUESTED,
 456                                   skew, sp->hdr.serial, true, true);
 457         }
 458
 459         offset = sp->offset + nr_acks + 3;
 460         if (skb->len >= offset + sizeof(buf.info)) {
 461                 if (skb_copy_bits(skb, offset, &buf.info, sizeof(buf.info)) < 0)
 462                         return rxrpc_proto_abort("XAI", call, 0);
 463                 rxrpc_input_ackinfo(call, skb, &buf.info);
 464         }
 465
 466         if (first_soft_ack == 0)
 467                 return rxrpc_proto_abort("AK0", call, 0);
 468
 469         /* Ignore ACKs unless we are or have just been transmitting. */
 470         switch (call->state) {
 471         case RXRPC_CALL_CLIENT_SEND_REQUEST:
 472         case RXRPC_CALL_CLIENT_AWAIT_REPLY:
 473         case RXRPC_CALL_SERVER_SEND_REPLY:
 474         case RXRPC_CALL_SERVER_AWAIT_ACK:
 475                 break;
 476         default:
 477                 return;
 478         }
 479
 480         /* Discard any out-of-order or duplicate ACKs. */
 481         if ((int)sp->hdr.serial - (int)call->acks_latest <= 0) {
 482                 _debug("discard ACK %d <= %d",
 483                        sp->hdr.serial, call->acks_latest);
 484                 return;
 485         }
 486         call->acks_latest = sp->hdr.serial;
 487
 488         if (test_bit(RXRPC_CALL_TX_LAST, &call->flags) &&
 489             hard_ack == call->tx_top) {
 490                 rxrpc_end_tx_phase(call, "ETA");
 491                 return;
 492         }
 493
 494         if (before(hard_ack, call->tx_hard_ack) ||
 495             after(hard_ack, call->tx_top))
 496                 return rxrpc_proto_abort("AKW", call, 0);
 497
 498         if (after(hard_ack, call->tx_hard_ack))
 499                 rxrpc_rotate_tx_window(call, hard_ack);
 500
 501         if (after(first_soft_ack, call->tx_top))
 502                 return;
 503
 504         if (nr_acks > call->tx_top - first_soft_ack + 1)
 505                 nr_acks = first_soft_ack - call->tx_top + 1;
 506         if (skb_copy_bits(skb, sp->offset, buf.acks, nr_acks) < 0)
 507                 return rxrpc_proto_abort("XSA", call, 0);
 508         rxrpc_input_soft_acks(call, buf.acks, first_soft_ack, nr_acks);
 509 }
 510
 511 /*
 512  * Process an ACKALL packet.
 513  */
 514 static void rxrpc_input_ackall(struct rxrpc_call *call, struct sk_buff *skb)
 515 {
 516         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 517
 518         _proto("Rx ACKALL %%%u", sp->hdr.serial);
 519
 520         rxrpc_end_tx_phase(call, "ETL");
 521 }
 522
 523 /*
 524  * Process an ABORT packet.
 525  */
 526 static void rxrpc_input_abort(struct rxrpc_call *call, struct sk_buff *skb)
 527 {
 528         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 529         __be32 wtmp;
 530         u32 abort_code = RX_CALL_DEAD;
 531
 532         _enter("");
 533
 534         if (skb->len >= 4 &&
 535             skb_copy_bits(skb, sp->offset, &wtmp, sizeof(wtmp)) >= 0)
 536                 abort_code = ntohl(wtmp);
 537
 538         _proto("Rx ABORT %%%u { %x }", sp->hdr.serial, abort_code);
 539
 540         if (rxrpc_set_call_completion(call, RXRPC_CALL_REMOTELY_ABORTED,
 541                                       abort_code, ECONNABORTED))
 542                 rxrpc_notify_socket(call);
 543 }
 544
 545 /*
 546  * Process an incoming call packet.
 547  */
 548 static void rxrpc_input_call_packet(struct rxrpc_call *call,
 549                                     struct sk_buff *skb, u16 skew)
 550 {
 551         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 552
 553         _enter("%p,%p", call, skb);
 554
 555         switch (sp->hdr.type) {
 556         case RXRPC_PACKET_TYPE_DATA:
 557                 rxrpc_input_data(call, skb, skew);
 558                 break;
 559
 560         case RXRPC_PACKET_TYPE_ACK:
 561                 rxrpc_input_ack(call, skb, skew);
 562                 break;
 563
 564         case RXRPC_PACKET_TYPE_BUSY:
 565                 _proto("Rx BUSY %%%u", sp->hdr.serial);
 566
 567                 /* Just ignore BUSY packets from the server; the retry and
 568                  * lifespan timers will take care of business.  BUSY packets
 569                  * from the client don't make sense.
 570                  */
 571                 break;
 572
 573         case RXRPC_PACKET_TYPE_ABORT:
 574                 rxrpc_input_abort(call, skb);
 575                 break;
 576
 577         case RXRPC_PACKET_TYPE_ACKALL:
 578                 rxrpc_input_ackall(call, skb);
 579                 break;
 580
 581         default:
 582                 _proto("Rx %s %%%u", rxrpc_pkts[sp->hdr.type], sp->hdr.serial);
 583                 break;
 584         }
 585
 586         _leave("");
 587 }
 588
 589 /*
 590  * post connection-level events to the connection
 591  * - this includes challenges, responses, some aborts and call terminal packet
 592  *   retransmission.
 593  */
 594 static void rxrpc_post_packet_to_conn(struct rxrpc_connection *conn,
 595                                       struct sk_buff *skb)
 596 {
 597         _enter("%p,%p", conn, skb);
 598
 599         skb_queue_tail(&conn->rx_queue, skb);
 600         rxrpc_queue_conn(conn);
 601 }
 602
 603 /*
 604  * post endpoint-level events to the local endpoint
 605  * - this includes debug and version messages
 606  */
 607 static void rxrpc_post_packet_to_local(struct rxrpc_local *local,
 608                                        struct sk_buff *skb)
 609 {
 610         _enter("%p,%p", local, skb);
 611
 612         skb_queue_tail(&local->event_queue, skb);
 613         rxrpc_queue_local(local);
 614 }
 615
 616 /*
 617  * put a packet up for transport-level abort
 618  */
 619 static void rxrpc_reject_packet(struct rxrpc_local *local, struct sk_buff *skb)
 620 {
 621         CHECK_SLAB_OKAY(&local->usage);
 622
 623         skb_queue_tail(&local->reject_queue, skb);
 624         rxrpc_queue_local(local);
 625 }
 626
 627 /*
 628  * Extract the wire header from a packet and translate the byte order.
 629  */
 630 static noinline
 631 int rxrpc_extract_header(struct rxrpc_skb_priv *sp, struct sk_buff *skb)
 632 {
 633         struct rxrpc_wire_header whdr;
 634
 635         /* dig out the RxRPC connection details */
 636         if (skb_copy_bits(skb, 0, &whdr, sizeof(whdr)) < 0)
 637                 return -EBADMSG;
 638
 639         memset(sp, 0, sizeof(*sp));
 640         sp->hdr.epoch           = ntohl(whdr.epoch);
 641         sp->hdr.cid             = ntohl(whdr.cid);
 642         sp->hdr.callNumber      = ntohl(whdr.callNumber);
 643         sp->hdr.seq             = ntohl(whdr.seq);
 644         sp->hdr.serial          = ntohl(whdr.serial);
 645         sp->hdr.flags           = whdr.flags;
 646         sp->hdr.type            = whdr.type;
 647         sp->hdr.userStatus      = whdr.userStatus;
 648         sp->hdr.securityIndex   = whdr.securityIndex;
 649         sp->hdr._rsvd           = ntohs(whdr._rsvd);
 650         sp->hdr.serviceId       = ntohs(whdr.serviceId);
 651         sp->offset = sizeof(whdr);
 652         return 0;
 653 }
 654
 655 /*
 656  * handle data received on the local endpoint
 657  * - may be called in interrupt context
 658  *
 659  * The socket is locked by the caller and this prevents the socket from being
 660  * shut down and the local endpoint from going away, thus sk_user_data will not
 661  * be cleared until this function returns.
 662  */
 663 void rxrpc_data_ready(struct sock *udp_sk)
 664 {
 665         struct rxrpc_connection *conn;
 666         struct rxrpc_channel *chan;
 667         struct rxrpc_call *call;
 668         struct rxrpc_skb_priv *sp;
 669         struct rxrpc_local *local = udp_sk->sk_user_data;
 670         struct sk_buff *skb;
 671         unsigned int channel;
 672         int ret, skew;
 673
 674         _enter("%p", udp_sk);
 675
 676         ASSERT(!irqs_disabled());
 677
 678         skb = skb_recv_datagram(udp_sk, 0, 1, &ret);
 679         if (!skb) {
 680                 if (ret == -EAGAIN)
 681                         return;
 682                 _debug("UDP socket error %d", ret);
 683                 return;
 684         }
 685
 686         rxrpc_new_skb(skb);
 687
 688         _net("recv skb %p", skb);
 689
 690         /* we'll probably need to checksum it (didn't call sock_recvmsg) */
 691         if (skb_checksum_complete(skb)) {
 692                 rxrpc_free_skb(skb);
 693                 __UDP_INC_STATS(&init_net, UDP_MIB_INERRORS, 0);
 694                 _leave(" [CSUM failed]");
 695                 return;
 696         }
 697
 698         __UDP_INC_STATS(&init_net, UDP_MIB_INDATAGRAMS, 0);
 699
 700         /* The socket buffer we have is owned by UDP, with UDP's data all over
 701          * it, but we really want our own data there.
 702          */
 703         skb_orphan(skb);
 704         sp = rxrpc_skb(skb);
 705
 706         _net("Rx UDP packet from %08x:%04hu",
 707              ntohl(ip_hdr(skb)->saddr), ntohs(udp_hdr(skb)->source));
 708
 709         /* dig out the RxRPC connection details */
 710         if (rxrpc_extract_header(sp, skb) < 0)
 711                 goto bad_message;
 712         trace_rxrpc_rx_packet(sp);
 713
 714         _net("Rx RxRPC %s ep=%x call=%x:%x",
 715              sp->hdr.flags & RXRPC_CLIENT_INITIATED ? "ToServer" : "ToClient",
 716              sp->hdr.epoch, sp->hdr.cid, sp->hdr.callNumber);
 717
 718         if (sp->hdr.type >= RXRPC_N_PACKET_TYPES ||
 719             !((RXRPC_SUPPORTED_PACKET_TYPES >> sp->hdr.type) & 1)) {
 720                 _proto("Rx Bad Packet Type %u", sp->hdr.type);
 721                 goto bad_message;
 722         }
 723
 724         switch (sp->hdr.type) {
 725         case RXRPC_PACKET_TYPE_VERSION:
 726                 rxrpc_post_packet_to_local(local, skb);
 727                 goto out;
 728
 729         case RXRPC_PACKET_TYPE_BUSY:
 730                 if (sp->hdr.flags & RXRPC_CLIENT_INITIATED)
 731                         goto discard;
 732
 733         case RXRPC_PACKET_TYPE_DATA:
 734                 if (sp->hdr.callNumber == 0)
 735                         goto bad_message;
 736                 if (sp->hdr.flags & RXRPC_JUMBO_PACKET &&
 737                     !rxrpc_validate_jumbo(skb))
 738                         goto bad_message;
 739                 break;
 740         }
 741
 742         rcu_read_lock();
 743
 744         conn = rxrpc_find_connection_rcu(local, skb);
 745         if (conn) {
 746                 if (sp->hdr.securityIndex != conn->security_ix)
 747                         goto wrong_security;
 748
 749                 if (sp->hdr.callNumber == 0) {
 750                         /* Connection-level packet */
 751                         _debug("CONN %p {%d}", conn, conn->debug_id);
 752                         rxrpc_post_packet_to_conn(conn, skb);
 753                         goto out_unlock;
 754                 }
 755
 756                 /* Note the serial number skew here */
 757                 skew = (int)sp->hdr.serial - (int)conn->hi_serial;
 758                 if (skew >= 0) {
 759                         if (skew > 0)
 760                                 conn->hi_serial = sp->hdr.serial;
 761                 } else {
 762                         skew = -skew;
 763                         skew = min(skew, 65535);
 764                 }
 765
 766                 /* Call-bound packets are routed by connection channel. */
 767                 channel = sp->hdr.cid & RXRPC_CHANNELMASK;
 768                 chan = &conn->channels[channel];
 769
 770                 /* Ignore really old calls */
 771                 if (sp->hdr.callNumber < chan->last_call)
 772                         goto discard_unlock;
 773
 774                 if (sp->hdr.callNumber == chan->last_call) {
 775                         /* For the previous service call, if completed successfully, we
 776                          * discard all further packets.
 777                          */
 778                         if (rxrpc_conn_is_service(conn) &&
 779                             (chan->last_type == RXRPC_PACKET_TYPE_ACK ||
 780                              sp->hdr.type == RXRPC_PACKET_TYPE_ABORT))
 781                                 goto discard_unlock;
 782
 783                         /* But otherwise we need to retransmit the final packet from
 784                          * data cached in the connection record.
 785                          */
 786                         rxrpc_post_packet_to_conn(conn, skb);
 787                         goto out_unlock;
 788                 }
 789
 790                 call = rcu_dereference(chan->call);
 791         } else {
 792                 skew = 0;
 793                 call = NULL;
 794         }
 795
 796         if (!call || atomic_read(&call->usage) == 0) {
 797                 if (!(sp->hdr.type & RXRPC_CLIENT_INITIATED) ||
 798                     sp->hdr.callNumber == 0 ||
 799                     sp->hdr.type != RXRPC_PACKET_TYPE_DATA)
 800                         goto bad_message_unlock;
 801                 if (sp->hdr.seq != 1)
 802                         goto discard_unlock;
 803                 call = rxrpc_new_incoming_call(local, conn, skb);
 804                 if (!call) {
 805                         rcu_read_unlock();
 806                         goto reject_packet;
 807                 }
 808         }
 809
 810         rxrpc_input_call_packet(call, skb, skew);
 811         goto discard_unlock;
 812
 813 discard_unlock:
 814         rcu_read_unlock();
 815 discard:
 816         rxrpc_free_skb(skb);
 817 out:
 818         trace_rxrpc_rx_done(0, 0);
 819         return;
 820
 821 out_unlock:
 822         rcu_read_unlock();
 823         goto out;
 824
 825 wrong_security:
 826         rcu_read_unlock();
 827         trace_rxrpc_abort("SEC", sp->hdr.cid, sp->hdr.callNumber, sp->hdr.seq,
 828                           RXKADINCONSISTENCY, EBADMSG);
 829         skb->priority = RXKADINCONSISTENCY;
 830         goto post_abort;
 831
 832 bad_message_unlock:
 833         rcu_read_unlock();
 834 bad_message:
 835         trace_rxrpc_abort("BAD", sp->hdr.cid, sp->hdr.callNumber, sp->hdr.seq,
 836                           RX_PROTOCOL_ERROR, EBADMSG);
 837         skb->priority = RX_PROTOCOL_ERROR;
 838 post_abort:
 839         skb->mark = RXRPC_SKB_MARK_LOCAL_ABORT;
 840 reject_packet:
 841         trace_rxrpc_rx_done(skb->mark, skb->priority);
 842         rxrpc_reject_packet(local, skb);
 843         _leave(" [badmsg]");
 844 }