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  * Ping the other end to fill our RTT cache and to retrieve the rwind
  41  * and MTU parameters.
  42  */
  43 static void rxrpc_send_ping(struct rxrpc_call *call, struct sk_buff *skb,
  44                             int skew)
  45 {
  46         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
  47         ktime_t now = skb->tstamp;
  48
  49         if (call->peer->rtt_usage < 3 ||
  50             ktime_before(ktime_add_ms(call->peer->rtt_last_req, 1000), now))
  51                 rxrpc_propose_ACK(call, RXRPC_ACK_PING, skew, sp->hdr.serial,
  52                                   true, true);
  53 }
  54
  55 /*
  56  * Apply a hard ACK by advancing the Tx window.
  57  */
  58 static void rxrpc_rotate_tx_window(struct rxrpc_call *call, rxrpc_seq_t to)
  59 {
  60         struct sk_buff *skb, *list = NULL;
  61         int ix;
  62         u8 annotation;
  63
  64         spin_lock(&call->lock);
  65
  66         while (before(call->tx_hard_ack, to)) {
  67                 call->tx_hard_ack++;
  68                 ix = call->tx_hard_ack & RXRPC_RXTX_BUFF_MASK;
  69                 skb = call->rxtx_buffer[ix];
  70                 annotation = call->rxtx_annotations[ix];
  71                 rxrpc_see_skb(skb, rxrpc_skb_tx_rotated);
  72                 call->rxtx_buffer[ix] = NULL;
  73                 call->rxtx_annotations[ix] = 0;
  74                 skb->next = list;
  75                 list = skb;
  76
  77                 if (annotation & RXRPC_TX_ANNO_LAST)
  78                         set_bit(RXRPC_CALL_TX_LAST, &call->flags);
  79         }
  80
  81         spin_unlock(&call->lock);
  82
  83         trace_rxrpc_transmit(call, (test_bit(RXRPC_CALL_TX_LAST, &call->flags) ?
  84                                     rxrpc_transmit_rotate_last :
  85                                     rxrpc_transmit_rotate));
  86         wake_up(&call->waitq);
  87
  88         while (list) {
  89                 skb = list;
  90                 list = skb->next;
  91                 skb->next = NULL;
  92                 rxrpc_free_skb(skb, rxrpc_skb_tx_freed);
  93         }
  94 }
  95
  96 /*
  97  * End the transmission phase of a call.
  98  *
  99  * This occurs when we get an ACKALL packet, the first DATA packet of a reply,
 100  * or a final ACK packet.
 101  */
 102 static bool rxrpc_end_tx_phase(struct rxrpc_call *call, bool reply_begun,
 103                                const char *abort_why)
 104 {
 105
 106         ASSERT(test_bit(RXRPC_CALL_TX_LAST, &call->flags));
 107
 108         write_lock(&call->state_lock);
 109
 110         switch (call->state) {
 111         case RXRPC_CALL_CLIENT_SEND_REQUEST:
 112         case RXRPC_CALL_CLIENT_AWAIT_REPLY:
 113                 if (reply_begun)
 114                         call->state = RXRPC_CALL_CLIENT_RECV_REPLY;
 115                 else
 116                         call->state = RXRPC_CALL_CLIENT_AWAIT_REPLY;
 117                 break;
 118
 119         case RXRPC_CALL_SERVER_AWAIT_ACK:
 120                 __rxrpc_call_completed(call);
 121                 rxrpc_notify_socket(call);
 122                 break;
 123
 124         default:
 125                 goto bad_state;
 126         }
 127
 128         write_unlock(&call->state_lock);
 129         if (call->state == RXRPC_CALL_CLIENT_AWAIT_REPLY) {
 130                 trace_rxrpc_transmit(call, rxrpc_transmit_await_reply);
 131         } else {
 132                 trace_rxrpc_transmit(call, rxrpc_transmit_end);
 133         }
 134         _leave(" = ok");
 135         return true;
 136
 137 bad_state:
 138         write_unlock(&call->state_lock);
 139         kdebug("end_tx %s", rxrpc_call_states[call->state]);
 140         rxrpc_proto_abort(abort_why, call, call->tx_top);
 141         return false;
 142 }
 143
 144 /*
 145  * Begin the reply reception phase of a call.
 146  */
 147 static bool rxrpc_receiving_reply(struct rxrpc_call *call)
 148 {
 149         rxrpc_seq_t top = READ_ONCE(call->tx_top);
 150
 151         if (!test_bit(RXRPC_CALL_TX_LAST, &call->flags))
 152                 rxrpc_rotate_tx_window(call, top);
 153         if (!test_bit(RXRPC_CALL_TX_LAST, &call->flags)) {
 154                 rxrpc_proto_abort("TXL", call, top);
 155                 return false;
 156         }
 157         if (!rxrpc_end_tx_phase(call, true, "ETD"))
 158                 return false;
 159         call->tx_phase = false;
 160         return true;
 161 }
 162
 163 /*
 164  * Scan a jumbo packet to validate its structure and to work out how many
 165  * subpackets it contains.
 166  *
 167  * A jumbo packet is a collection of consecutive packets glued together with
 168  * little headers between that indicate how to change the initial header for
 169  * each subpacket.
 170  *
 171  * RXRPC_JUMBO_PACKET must be set on all but the last subpacket - and all but
 172  * the last are RXRPC_JUMBO_DATALEN in size.  The last subpacket may be of any
 173  * size.
 174  */
 175 static bool rxrpc_validate_jumbo(struct sk_buff *skb)
 176 {
 177         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 178         unsigned int offset = sp->offset;
 179         unsigned int len = skb->len;
 180         int nr_jumbo = 1;
 181         u8 flags = sp->hdr.flags;
 182
 183         do {
 184                 nr_jumbo++;
 185                 if (len - offset < RXRPC_JUMBO_SUBPKTLEN)
 186                         goto protocol_error;
 187                 if (flags & RXRPC_LAST_PACKET)
 188                         goto protocol_error;
 189                 offset += RXRPC_JUMBO_DATALEN;
 190                 if (skb_copy_bits(skb, offset, &flags, 1) < 0)
 191                         goto protocol_error;
 192                 offset += sizeof(struct rxrpc_jumbo_header);
 193         } while (flags & RXRPC_JUMBO_PACKET);
 194
 195         sp->nr_jumbo = nr_jumbo;
 196         return true;
 197
 198 protocol_error:
 199         return false;
 200 }
 201
 202 /*
 203  * Handle reception of a duplicate packet.
 204  *
 205  * We have to take care to avoid an attack here whereby we're given a series of
 206  * jumbograms, each with a sequence number one before the preceding one and
 207  * filled up to maximum UDP size.  If they never send us the first packet in
 208  * the sequence, they can cause us to have to hold on to around 2MiB of kernel
 209  * space until the call times out.
 210  *
 211  * We limit the space usage by only accepting three duplicate jumbo packets per
 212  * call.  After that, we tell the other side we're no longer accepting jumbos
 213  * (that information is encoded in the ACK packet).
 214  */
 215 static void rxrpc_input_dup_data(struct rxrpc_call *call, rxrpc_seq_t seq,
 216                                  u8 annotation, bool *_jumbo_bad)
 217 {
 218         /* Discard normal packets that are duplicates. */
 219         if (annotation == 0)
 220                 return;
 221
 222         /* Skip jumbo subpackets that are duplicates.  When we've had three or
 223          * more partially duplicate jumbo packets, we refuse to take any more
 224          * jumbos for this call.
 225          */
 226         if (!*_jumbo_bad) {
 227                 call->nr_jumbo_bad++;
 228                 *_jumbo_bad = true;
 229         }
 230 }
 231
 232 /*
 233  * Process a DATA packet, adding the packet to the Rx ring.
 234  */
 235 static void rxrpc_input_data(struct rxrpc_call *call, struct sk_buff *skb,
 236                              u16 skew)
 237 {
 238         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 239         unsigned int offset = sp->offset;
 240         unsigned int ix;
 241         rxrpc_serial_t serial = sp->hdr.serial, ack_serial = 0;
 242         rxrpc_seq_t seq = sp->hdr.seq, hard_ack;
 243         bool immediate_ack = false, jumbo_bad = false, queued;
 244         u16 len;
 245         u8 ack = 0, flags, annotation = 0;
 246
 247         _enter("{%u,%u},{%u,%u}",
 248                call->rx_hard_ack, call->rx_top, skb->len, seq);
 249
 250         _proto("Rx DATA %%%u { #%u f=%02x }",
 251                sp->hdr.serial, seq, sp->hdr.flags);
 252
 253         if (call->state >= RXRPC_CALL_COMPLETE)
 254                 return;
 255
 256         /* Received data implicitly ACKs all of the request packets we sent
 257          * when we're acting as a client.
 258          */
 259         if ((call->state == RXRPC_CALL_CLIENT_SEND_REQUEST ||
 260              call->state == RXRPC_CALL_CLIENT_AWAIT_REPLY) &&
 261             !rxrpc_receiving_reply(call))
 262                 return;
 263
 264         call->ackr_prev_seq = seq;
 265
 266         hard_ack = READ_ONCE(call->rx_hard_ack);
 267         if (after(seq, hard_ack + call->rx_winsize)) {
 268                 ack = RXRPC_ACK_EXCEEDS_WINDOW;
 269                 ack_serial = serial;
 270                 goto ack;
 271         }
 272
 273         flags = sp->hdr.flags;
 274         if (flags & RXRPC_JUMBO_PACKET) {
 275                 if (call->nr_jumbo_bad > 3) {
 276                         ack = RXRPC_ACK_NOSPACE;
 277                         ack_serial = serial;
 278                         goto ack;
 279                 }
 280                 annotation = 1;
 281         }
 282
 283 next_subpacket:
 284         queued = false;
 285         ix = seq & RXRPC_RXTX_BUFF_MASK;
 286         len = skb->len;
 287         if (flags & RXRPC_JUMBO_PACKET)
 288                 len = RXRPC_JUMBO_DATALEN;
 289
 290         if (flags & RXRPC_LAST_PACKET) {
 291                 if (test_bit(RXRPC_CALL_RX_LAST, &call->flags) &&
 292                     seq != call->rx_top)
 293                         return rxrpc_proto_abort("LSN", call, seq);
 294         } else {
 295                 if (test_bit(RXRPC_CALL_RX_LAST, &call->flags) &&
 296                     after_eq(seq, call->rx_top))
 297                         return rxrpc_proto_abort("LSA", call, seq);
 298         }
 299
 300         if (before_eq(seq, hard_ack)) {
 301                 ack = RXRPC_ACK_DUPLICATE;
 302                 ack_serial = serial;
 303                 goto skip;
 304         }
 305
 306         if (flags & RXRPC_REQUEST_ACK && !ack) {
 307                 ack = RXRPC_ACK_REQUESTED;
 308                 ack_serial = serial;
 309         }
 310
 311         if (call->rxtx_buffer[ix]) {
 312                 rxrpc_input_dup_data(call, seq, annotation, &jumbo_bad);
 313                 if (ack != RXRPC_ACK_DUPLICATE) {
 314                         ack = RXRPC_ACK_DUPLICATE;
 315                         ack_serial = serial;
 316                 }
 317                 immediate_ack = true;
 318                 goto skip;
 319         }
 320
 321         /* Queue the packet.  We use a couple of memory barriers here as need
 322          * to make sure that rx_top is perceived to be set after the buffer
 323          * pointer and that the buffer pointer is set after the annotation and
 324          * the skb data.
 325          *
 326          * Barriers against rxrpc_recvmsg_data() and rxrpc_rotate_rx_window()
 327          * and also rxrpc_fill_out_ack().
 328          */
 329         rxrpc_get_skb(skb, rxrpc_skb_rx_got);
 330         call->rxtx_annotations[ix] = annotation;
 331         smp_wmb();
 332         call->rxtx_buffer[ix] = skb;
 333         if (after(seq, call->rx_top))
 334                 smp_store_release(&call->rx_top, seq);
 335         if (flags & RXRPC_LAST_PACKET) {
 336                 set_bit(RXRPC_CALL_RX_LAST, &call->flags);
 337                 trace_rxrpc_receive(call, rxrpc_receive_queue_last, serial, seq);
 338         } else {
 339                 trace_rxrpc_receive(call, rxrpc_receive_queue, serial, seq);
 340         }
 341         queued = true;
 342
 343         if (after_eq(seq, call->rx_expect_next)) {
 344                 if (after(seq, call->rx_expect_next)) {
 345                         _net("OOS %u > %u", seq, call->rx_expect_next);
 346                         ack = RXRPC_ACK_OUT_OF_SEQUENCE;
 347                         ack_serial = serial;
 348                 }
 349                 call->rx_expect_next = seq + 1;
 350         }
 351
 352 skip:
 353         offset += len;
 354         if (flags & RXRPC_JUMBO_PACKET) {
 355                 if (skb_copy_bits(skb, offset, &flags, 1) < 0)
 356                         return rxrpc_proto_abort("XJF", call, seq);
 357                 offset += sizeof(struct rxrpc_jumbo_header);
 358                 seq++;
 359                 serial++;
 360                 annotation++;
 361                 if (flags & RXRPC_JUMBO_PACKET)
 362                         annotation |= RXRPC_RX_ANNO_JLAST;
 363                 if (after(seq, hard_ack + call->rx_winsize)) {
 364                         ack = RXRPC_ACK_EXCEEDS_WINDOW;
 365                         ack_serial = serial;
 366                         if (!jumbo_bad) {
 367                                 call->nr_jumbo_bad++;
 368                                 jumbo_bad = true;
 369                         }
 370                         goto ack;
 371                 }
 372
 373                 _proto("Rx DATA Jumbo %%%u", serial);
 374                 goto next_subpacket;
 375         }
 376
 377         if (queued && flags & RXRPC_LAST_PACKET && !ack) {
 378                 ack = RXRPC_ACK_DELAY;
 379                 ack_serial = serial;
 380         }
 381
 382 ack:
 383         if (ack)
 384                 rxrpc_propose_ACK(call, ack, skew, ack_serial,
 385                                   immediate_ack, true);
 386
 387         if (sp->hdr.seq == READ_ONCE(call->rx_hard_ack) + 1)
 388                 rxrpc_notify_socket(call);
 389         _leave(" [queued]");
 390 }
 391
 392 /*
 393  * Process a requested ACK.
 394  */
 395 static void rxrpc_input_requested_ack(struct rxrpc_call *call,
 396                                       ktime_t resp_time,
 397                                       rxrpc_serial_t orig_serial,
 398                                       rxrpc_serial_t ack_serial)
 399 {
 400         struct rxrpc_skb_priv *sp;
 401         struct sk_buff *skb;
 402         ktime_t sent_at;
 403         int ix;
 404
 405         for (ix = 0; ix < RXRPC_RXTX_BUFF_SIZE; ix++) {
 406                 skb = call->rxtx_buffer[ix];
 407                 if (!skb)
 408                         continue;
 409
 410                 sp = rxrpc_skb(skb);
 411                 if (sp->hdr.serial != orig_serial)
 412                         continue;
 413                 smp_rmb();
 414                 sent_at = skb->tstamp;
 415                 goto found;
 416         }
 417         return;
 418
 419 found:
 420         rxrpc_peer_add_rtt(call, rxrpc_rtt_rx_requested_ack,
 421                            orig_serial, ack_serial, sent_at, resp_time);
 422 }
 423
 424 /*
 425  * Process a ping response.
 426  */
 427 static void rxrpc_input_ping_response(struct rxrpc_call *call,
 428                                       ktime_t resp_time,
 429                                       rxrpc_serial_t orig_serial,
 430                                       rxrpc_serial_t ack_serial)
 431 {
 432         rxrpc_serial_t ping_serial;
 433         ktime_t ping_time;
 434
 435         ping_time = call->ackr_ping_time;
 436         smp_rmb();
 437         ping_serial = call->ackr_ping;
 438
 439         if (!test_bit(RXRPC_CALL_PINGING, &call->flags) ||
 440             before(orig_serial, ping_serial))
 441                 return;
 442         clear_bit(RXRPC_CALL_PINGING, &call->flags);
 443         if (after(orig_serial, ping_serial))
 444                 return;
 445
 446         rxrpc_peer_add_rtt(call, rxrpc_rtt_rx_ping_response,
 447                            orig_serial, ack_serial, ping_time, resp_time);
 448 }
 449
 450 /*
 451  * Process the extra information that may be appended to an ACK packet
 452  */
 453 static void rxrpc_input_ackinfo(struct rxrpc_call *call, struct sk_buff *skb,
 454                                 struct rxrpc_ackinfo *ackinfo)
 455 {
 456         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 457         struct rxrpc_peer *peer;
 458         unsigned int mtu;
 459         u32 rwind = ntohl(ackinfo->rwind);
 460
 461         _proto("Rx ACK %%%u Info { rx=%u max=%u rwin=%u jm=%u }",
 462                sp->hdr.serial,
 463                ntohl(ackinfo->rxMTU), ntohl(ackinfo->maxMTU),
 464                rwind, ntohl(ackinfo->jumbo_max));
 465
 466         if (rwind > RXRPC_RXTX_BUFF_SIZE - 1)
 467                 rwind = RXRPC_RXTX_BUFF_SIZE - 1;
 468         call->tx_winsize = rwind;
 469
 470         mtu = min(ntohl(ackinfo->rxMTU), ntohl(ackinfo->maxMTU));
 471
 472         peer = call->peer;
 473         if (mtu < peer->maxdata) {
 474                 spin_lock_bh(&peer->lock);
 475                 peer->maxdata = mtu;
 476                 peer->mtu = mtu + peer->hdrsize;
 477                 spin_unlock_bh(&peer->lock);
 478                 _net("Net MTU %u (maxdata %u)", peer->mtu, peer->maxdata);
 479         }
 480 }
 481
 482 /*
 483  * Process individual soft ACKs.
 484  *
 485  * Each ACK in the array corresponds to one packet and can be either an ACK or
 486  * a NAK.  If we get find an explicitly NAK'd packet we resend immediately;
 487  * packets that lie beyond the end of the ACK list are scheduled for resend by
 488  * the timer on the basis that the peer might just not have processed them at
 489  * the time the ACK was sent.
 490  */
 491 static void rxrpc_input_soft_acks(struct rxrpc_call *call, u8 *acks,
 492                                   rxrpc_seq_t seq, int nr_acks)
 493 {
 494         bool resend = false;
 495         int ix;
 496         u8 annotation, anno_type;
 497
 498         for (; nr_acks > 0; nr_acks--, seq++) {
 499                 ix = seq & RXRPC_RXTX_BUFF_MASK;
 500                 annotation = call->rxtx_annotations[ix];
 501                 anno_type = annotation & RXRPC_TX_ANNO_MASK;
 502                 annotation &= ~RXRPC_TX_ANNO_MASK;
 503                 switch (*acks++) {
 504                 case RXRPC_ACK_TYPE_ACK:
 505                         if (anno_type == RXRPC_TX_ANNO_ACK)
 506                                 continue;
 507                         call->rxtx_annotations[ix] =
 508                                 RXRPC_TX_ANNO_ACK | annotation;
 509                         break;
 510                 case RXRPC_ACK_TYPE_NACK:
 511                         if (anno_type == RXRPC_TX_ANNO_NAK)
 512                                 continue;
 513                         if (anno_type == RXRPC_TX_ANNO_RETRANS)
 514                                 continue;
 515                         call->rxtx_annotations[ix] =
 516                                 RXRPC_TX_ANNO_NAK | annotation;
 517                         resend = true;
 518                         break;
 519                 default:
 520                         return rxrpc_proto_abort("SFT", call, 0);
 521                 }
 522         }
 523
 524         if (resend &&
 525             !test_and_set_bit(RXRPC_CALL_EV_RESEND, &call->events))
 526                 rxrpc_queue_call(call);
 527 }
 528
 529 /*
 530  * Process an ACK packet.
 531  *
 532  * ack.firstPacket is the sequence number of the first soft-ACK'd/NAK'd packet
 533  * in the ACK array.  Anything before that is hard-ACK'd and may be discarded.
 534  *
 535  * A hard-ACK means that a packet has been processed and may be discarded; a
 536  * soft-ACK means that the packet may be discarded and retransmission
 537  * requested.  A phase is complete when all packets are hard-ACK'd.
 538  */
 539 static void rxrpc_input_ack(struct rxrpc_call *call, struct sk_buff *skb,
 540                             u16 skew)
 541 {
 542         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 543         union {
 544                 struct rxrpc_ackpacket ack;
 545                 struct rxrpc_ackinfo info;
 546                 u8 acks[RXRPC_MAXACKS];
 547         } buf;
 548         rxrpc_serial_t acked_serial;
 549         rxrpc_seq_t first_soft_ack, hard_ack;
 550         int nr_acks, offset;
 551
 552         _enter("");
 553
 554         if (skb_copy_bits(skb, sp->offset, &buf.ack, sizeof(buf.ack)) < 0) {
 555                 _debug("extraction failure");
 556                 return rxrpc_proto_abort("XAK", call, 0);
 557         }
 558         sp->offset += sizeof(buf.ack);
 559
 560         acked_serial = ntohl(buf.ack.serial);
 561         first_soft_ack = ntohl(buf.ack.firstPacket);
 562         hard_ack = first_soft_ack - 1;
 563         nr_acks = buf.ack.nAcks;
 564
 565         trace_rxrpc_rx_ack(call, first_soft_ack, buf.ack.reason, nr_acks);
 566
 567         _proto("Rx ACK %%%u { m=%hu f=#%u p=#%u s=%%%u r=%s n=%u }",
 568                sp->hdr.serial,
 569                ntohs(buf.ack.maxSkew),
 570                first_soft_ack,
 571                ntohl(buf.ack.previousPacket),
 572                acked_serial,
 573                rxrpc_acks(buf.ack.reason),
 574                buf.ack.nAcks);
 575
 576         if (buf.ack.reason == RXRPC_ACK_PING_RESPONSE)
 577                 rxrpc_input_ping_response(call, skb->tstamp, acked_serial,
 578                                           sp->hdr.serial);
 579         if (buf.ack.reason == RXRPC_ACK_REQUESTED)
 580                 rxrpc_input_requested_ack(call, skb->tstamp, acked_serial,
 581                                           sp->hdr.serial);
 582
 583         if (buf.ack.reason == RXRPC_ACK_PING) {
 584                 _proto("Rx ACK %%%u PING Request", sp->hdr.serial);
 585                 rxrpc_propose_ACK(call, RXRPC_ACK_PING_RESPONSE,
 586                                   skew, sp->hdr.serial, true, true);
 587         } else if (sp->hdr.flags & RXRPC_REQUEST_ACK) {
 588                 rxrpc_propose_ACK(call, RXRPC_ACK_REQUESTED,
 589                                   skew, sp->hdr.serial, true, true);
 590         }
 591
 592         offset = sp->offset + nr_acks + 3;
 593         if (skb->len >= offset + sizeof(buf.info)) {
 594                 if (skb_copy_bits(skb, offset, &buf.info, sizeof(buf.info)) < 0)
 595                         return rxrpc_proto_abort("XAI", call, 0);
 596                 rxrpc_input_ackinfo(call, skb, &buf.info);
 597         }
 598
 599         if (first_soft_ack == 0)
 600                 return rxrpc_proto_abort("AK0", call, 0);
 601
 602         /* Ignore ACKs unless we are or have just been transmitting. */
 603         switch (call->state) {
 604         case RXRPC_CALL_CLIENT_SEND_REQUEST:
 605         case RXRPC_CALL_CLIENT_AWAIT_REPLY:
 606         case RXRPC_CALL_SERVER_SEND_REPLY:
 607         case RXRPC_CALL_SERVER_AWAIT_ACK:
 608                 break;
 609         default:
 610                 return;
 611         }
 612
 613         /* Discard any out-of-order or duplicate ACKs. */
 614         if (before_eq(sp->hdr.serial, call->acks_latest)) {
 615                 _debug("discard ACK %d <= %d",
 616                        sp->hdr.serial, call->acks_latest);
 617                 return;
 618         }
 619         call->acks_latest = sp->hdr.serial;
 620
 621         if (before(hard_ack, call->tx_hard_ack) ||
 622             after(hard_ack, call->tx_top))
 623                 return rxrpc_proto_abort("AKW", call, 0);
 624         if (nr_acks > call->tx_top - hard_ack)
 625                 return rxrpc_proto_abort("AKN", call, 0);
 626
 627         if (after(hard_ack, call->tx_hard_ack))
 628                 rxrpc_rotate_tx_window(call, hard_ack);
 629
 630         if (nr_acks > 0) {
 631                 if (skb_copy_bits(skb, sp->offset, buf.acks, nr_acks) < 0)
 632                         return rxrpc_proto_abort("XSA", call, 0);
 633                 rxrpc_input_soft_acks(call, buf.acks, first_soft_ack, nr_acks);
 634         }
 635
 636         if (test_bit(RXRPC_CALL_TX_LAST, &call->flags)) {
 637                 rxrpc_end_tx_phase(call, false, "ETA");
 638                 return;
 639         }
 640
 641 }
 642
 643 /*
 644  * Process an ACKALL packet.
 645  */
 646 static void rxrpc_input_ackall(struct rxrpc_call *call, struct sk_buff *skb)
 647 {
 648         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 649
 650         _proto("Rx ACKALL %%%u", sp->hdr.serial);
 651
 652         rxrpc_rotate_tx_window(call, call->tx_top);
 653         if (test_bit(RXRPC_CALL_TX_LAST, &call->flags))
 654                 rxrpc_end_tx_phase(call, false, "ETL");
 655 }
 656
 657 /*
 658  * Process an ABORT packet.
 659  */
 660 static void rxrpc_input_abort(struct rxrpc_call *call, struct sk_buff *skb)
 661 {
 662         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 663         __be32 wtmp;
 664         u32 abort_code = RX_CALL_DEAD;
 665
 666         _enter("");
 667
 668         if (skb->len >= 4 &&
 669             skb_copy_bits(skb, sp->offset, &wtmp, sizeof(wtmp)) >= 0)
 670                 abort_code = ntohl(wtmp);
 671
 672         _proto("Rx ABORT %%%u { %x }", sp->hdr.serial, abort_code);
 673
 674         if (rxrpc_set_call_completion(call, RXRPC_CALL_REMOTELY_ABORTED,
 675                                       abort_code, ECONNABORTED))
 676                 rxrpc_notify_socket(call);
 677 }
 678
 679 /*
 680  * Process an incoming call packet.
 681  */
 682 static void rxrpc_input_call_packet(struct rxrpc_call *call,
 683                                     struct sk_buff *skb, u16 skew)
 684 {
 685         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 686
 687         _enter("%p,%p", call, skb);
 688
 689         switch (sp->hdr.type) {
 690         case RXRPC_PACKET_TYPE_DATA:
 691                 rxrpc_input_data(call, skb, skew);
 692                 break;
 693
 694         case RXRPC_PACKET_TYPE_ACK:
 695                 rxrpc_input_ack(call, skb, skew);
 696                 break;
 697
 698         case RXRPC_PACKET_TYPE_BUSY:
 699                 _proto("Rx BUSY %%%u", sp->hdr.serial);
 700
 701                 /* Just ignore BUSY packets from the server; the retry and
 702                  * lifespan timers will take care of business.  BUSY packets
 703                  * from the client don't make sense.
 704                  */
 705                 break;
 706
 707         case RXRPC_PACKET_TYPE_ABORT:
 708                 rxrpc_input_abort(call, skb);
 709                 break;
 710
 711         case RXRPC_PACKET_TYPE_ACKALL:
 712                 rxrpc_input_ackall(call, skb);
 713                 break;
 714
 715         default:
 716                 _proto("Rx %s %%%u", rxrpc_pkts[sp->hdr.type], sp->hdr.serial);
 717                 break;
 718         }
 719
 720         _leave("");
 721 }
 722
 723 /*
 724  * post connection-level events to the connection
 725  * - this includes challenges, responses, some aborts and call terminal packet
 726  *   retransmission.
 727  */
 728 static void rxrpc_post_packet_to_conn(struct rxrpc_connection *conn,
 729                                       struct sk_buff *skb)
 730 {
 731         _enter("%p,%p", conn, skb);
 732
 733         skb_queue_tail(&conn->rx_queue, skb);
 734         rxrpc_queue_conn(conn);
 735 }
 736
 737 /*
 738  * post endpoint-level events to the local endpoint
 739  * - this includes debug and version messages
 740  */
 741 static void rxrpc_post_packet_to_local(struct rxrpc_local *local,
 742                                        struct sk_buff *skb)
 743 {
 744         _enter("%p,%p", local, skb);
 745
 746         skb_queue_tail(&local->event_queue, skb);
 747         rxrpc_queue_local(local);
 748 }
 749
 750 /*
 751  * put a packet up for transport-level abort
 752  */
 753 static void rxrpc_reject_packet(struct rxrpc_local *local, struct sk_buff *skb)
 754 {
 755         CHECK_SLAB_OKAY(&local->usage);
 756
 757         skb_queue_tail(&local->reject_queue, skb);
 758         rxrpc_queue_local(local);
 759 }
 760
 761 /*
 762  * Extract the wire header from a packet and translate the byte order.
 763  */
 764 static noinline
 765 int rxrpc_extract_header(struct rxrpc_skb_priv *sp, struct sk_buff *skb)
 766 {
 767         struct rxrpc_wire_header whdr;
 768
 769         /* dig out the RxRPC connection details */
 770         if (skb_copy_bits(skb, 0, &whdr, sizeof(whdr)) < 0)
 771                 return -EBADMSG;
 772
 773         memset(sp, 0, sizeof(*sp));
 774         sp->hdr.epoch           = ntohl(whdr.epoch);
 775         sp->hdr.cid             = ntohl(whdr.cid);
 776         sp->hdr.callNumber      = ntohl(whdr.callNumber);
 777         sp->hdr.seq             = ntohl(whdr.seq);
 778         sp->hdr.serial          = ntohl(whdr.serial);
 779         sp->hdr.flags           = whdr.flags;
 780         sp->hdr.type            = whdr.type;
 781         sp->hdr.userStatus      = whdr.userStatus;
 782         sp->hdr.securityIndex   = whdr.securityIndex;
 783         sp->hdr._rsvd           = ntohs(whdr._rsvd);
 784         sp->hdr.serviceId       = ntohs(whdr.serviceId);
 785         sp->offset = sizeof(whdr);
 786         return 0;
 787 }
 788
 789 /*
 790  * handle data received on the local endpoint
 791  * - may be called in interrupt context
 792  *
 793  * The socket is locked by the caller and this prevents the socket from being
 794  * shut down and the local endpoint from going away, thus sk_user_data will not
 795  * be cleared until this function returns.
 796  */
 797 void rxrpc_data_ready(struct sock *udp_sk)
 798 {
 799         struct rxrpc_connection *conn;
 800         struct rxrpc_channel *chan;
 801         struct rxrpc_call *call;
 802         struct rxrpc_skb_priv *sp;
 803         struct rxrpc_local *local = udp_sk->sk_user_data;
 804         struct sk_buff *skb;
 805         unsigned int channel;
 806         int ret, skew;
 807
 808         _enter("%p", udp_sk);
 809
 810         ASSERT(!irqs_disabled());
 811
 812         skb = skb_recv_datagram(udp_sk, 0, 1, &ret);
 813         if (!skb) {
 814                 if (ret == -EAGAIN)
 815                         return;
 816                 _debug("UDP socket error %d", ret);
 817                 return;
 818         }
 819
 820         rxrpc_new_skb(skb, rxrpc_skb_rx_received);
 821
 822         _net("recv skb %p", skb);
 823
 824         /* we'll probably need to checksum it (didn't call sock_recvmsg) */
 825         if (skb_checksum_complete(skb)) {
 826                 rxrpc_free_skb(skb, rxrpc_skb_rx_freed);
 827                 __UDP_INC_STATS(&init_net, UDP_MIB_INERRORS, 0);
 828                 _leave(" [CSUM failed]");
 829                 return;
 830         }
 831
 832         __UDP_INC_STATS(&init_net, UDP_MIB_INDATAGRAMS, 0);
 833
 834         /* The socket buffer we have is owned by UDP, with UDP's data all over
 835          * it, but we really want our own data there.
 836          */
 837         skb_orphan(skb);
 838         sp = rxrpc_skb(skb);
 839
 840         /* dig out the RxRPC connection details */
 841         if (rxrpc_extract_header(sp, skb) < 0)
 842                 goto bad_message;
 843
 844         if (IS_ENABLED(CONFIG_AF_RXRPC_INJECT_LOSS)) {
 845                 static int lose;
 846                 if ((lose++ & 7) == 7) {
 847                         trace_rxrpc_rx_lose(sp);
 848                         rxrpc_lose_skb(skb, rxrpc_skb_rx_lost);
 849                         return;
 850                 }
 851         }
 852
 853         trace_rxrpc_rx_packet(sp);
 854
 855         _net("Rx RxRPC %s ep=%x call=%x:%x",
 856              sp->hdr.flags & RXRPC_CLIENT_INITIATED ? "ToServer" : "ToClient",
 857              sp->hdr.epoch, sp->hdr.cid, sp->hdr.callNumber);
 858
 859         if (sp->hdr.type >= RXRPC_N_PACKET_TYPES ||
 860             !((RXRPC_SUPPORTED_PACKET_TYPES >> sp->hdr.type) & 1)) {
 861                 _proto("Rx Bad Packet Type %u", sp->hdr.type);
 862                 goto bad_message;
 863         }
 864
 865         switch (sp->hdr.type) {
 866         case RXRPC_PACKET_TYPE_VERSION:
 867                 rxrpc_post_packet_to_local(local, skb);
 868                 goto out;
 869
 870         case RXRPC_PACKET_TYPE_BUSY:
 871                 if (sp->hdr.flags & RXRPC_CLIENT_INITIATED)
 872                         goto discard;
 873
 874         case RXRPC_PACKET_TYPE_DATA:
 875                 if (sp->hdr.callNumber == 0)
 876                         goto bad_message;
 877                 if (sp->hdr.flags & RXRPC_JUMBO_PACKET &&
 878                     !rxrpc_validate_jumbo(skb))
 879                         goto bad_message;
 880                 break;
 881         }
 882
 883         rcu_read_lock();
 884
 885         conn = rxrpc_find_connection_rcu(local, skb);
 886         if (conn) {
 887                 if (sp->hdr.securityIndex != conn->security_ix)
 888                         goto wrong_security;
 889
 890                 if (sp->hdr.callNumber == 0) {
 891                         /* Connection-level packet */
 892                         _debug("CONN %p {%d}", conn, conn->debug_id);
 893                         rxrpc_post_packet_to_conn(conn, skb);
 894                         goto out_unlock;
 895                 }
 896
 897                 /* Note the serial number skew here */
 898                 skew = (int)sp->hdr.serial - (int)conn->hi_serial;
 899                 if (skew >= 0) {
 900                         if (skew > 0)
 901                                 conn->hi_serial = sp->hdr.serial;
 902                 } else {
 903                         skew = -skew;
 904                         skew = min(skew, 65535);
 905                 }
 906
 907                 /* Call-bound packets are routed by connection channel. */
 908                 channel = sp->hdr.cid & RXRPC_CHANNELMASK;
 909                 chan = &conn->channels[channel];
 910
 911                 /* Ignore really old calls */
 912                 if (sp->hdr.callNumber < chan->last_call)
 913                         goto discard_unlock;
 914
 915                 if (sp->hdr.callNumber == chan->last_call) {
 916                         /* For the previous service call, if completed successfully, we
 917                          * discard all further packets.
 918                          */
 919                         if (rxrpc_conn_is_service(conn) &&
 920                             (chan->last_type == RXRPC_PACKET_TYPE_ACK ||
 921                              sp->hdr.type == RXRPC_PACKET_TYPE_ABORT))
 922                                 goto discard_unlock;
 923
 924                         /* But otherwise we need to retransmit the final packet from
 925                          * data cached in the connection record.
 926                          */
 927                         rxrpc_post_packet_to_conn(conn, skb);
 928                         goto out_unlock;
 929                 }
 930
 931                 call = rcu_dereference(chan->call);
 932         } else {
 933                 skew = 0;
 934                 call = NULL;
 935         }
 936
 937         if (!call || atomic_read(&call->usage) == 0) {
 938                 if (!(sp->hdr.type & RXRPC_CLIENT_INITIATED) ||
 939                     sp->hdr.callNumber == 0 ||
 940                     sp->hdr.type != RXRPC_PACKET_TYPE_DATA)
 941                         goto bad_message_unlock;
 942                 if (sp->hdr.seq != 1)
 943                         goto discard_unlock;
 944                 call = rxrpc_new_incoming_call(local, conn, skb);
 945                 if (!call) {
 946                         rcu_read_unlock();
 947                         goto reject_packet;
 948                 }
 949                 rxrpc_send_ping(call, skb, skew);
 950         }
 951
 952         rxrpc_input_call_packet(call, skb, skew);
 953         goto discard_unlock;
 954
 955 discard_unlock:
 956         rcu_read_unlock();
 957 discard:
 958         rxrpc_free_skb(skb, rxrpc_skb_rx_freed);
 959 out:
 960         trace_rxrpc_rx_done(0, 0);
 961         return;
 962
 963 out_unlock:
 964         rcu_read_unlock();
 965         goto out;
 966
 967 wrong_security:
 968         rcu_read_unlock();
 969         trace_rxrpc_abort("SEC", sp->hdr.cid, sp->hdr.callNumber, sp->hdr.seq,
 970                           RXKADINCONSISTENCY, EBADMSG);
 971         skb->priority = RXKADINCONSISTENCY;
 972         goto post_abort;
 973
 974 bad_message_unlock:
 975         rcu_read_unlock();
 976 bad_message:
 977         trace_rxrpc_abort("BAD", sp->hdr.cid, sp->hdr.callNumber, sp->hdr.seq,
 978                           RX_PROTOCOL_ERROR, EBADMSG);
 979         skb->priority = RX_PROTOCOL_ERROR;
 980 post_abort:
 981         skb->mark = RXRPC_SKB_MARK_LOCAL_ABORT;
 982 reject_packet:
 983         trace_rxrpc_rx_done(skb->mark, skb->priority);
 984         rxrpc_reject_packet(local, skb);
 985         _leave(" [badmsg]");
 986 }