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                                   rxrpc_propose_ack_ping_for_params);
  54 }
  55
  56 /*
  57  * Apply a hard ACK by advancing the Tx window.
  58  */
  59 static void rxrpc_rotate_tx_window(struct rxrpc_call *call, rxrpc_seq_t to)
  60 {
  61         struct sk_buff *skb, *list = NULL;
  62         int ix;
  63         u8 annotation;
  64
  65         spin_lock(&call->lock);
  66
  67         while (before(call->tx_hard_ack, to)) {
  68                 call->tx_hard_ack++;
  69                 ix = call->tx_hard_ack & RXRPC_RXTX_BUFF_MASK;
  70                 skb = call->rxtx_buffer[ix];
  71                 annotation = call->rxtx_annotations[ix];
  72                 rxrpc_see_skb(skb, rxrpc_skb_tx_rotated);
  73                 call->rxtx_buffer[ix] = NULL;
  74                 call->rxtx_annotations[ix] = 0;
  75                 skb->next = list;
  76                 list = skb;
  77
  78                 if (annotation & RXRPC_TX_ANNO_LAST)
  79                         set_bit(RXRPC_CALL_TX_LAST, &call->flags);
  80         }
  81
  82         spin_unlock(&call->lock);
  83
  84         trace_rxrpc_transmit(call, (test_bit(RXRPC_CALL_TX_LAST, &call->flags) ?
  85                                     rxrpc_transmit_rotate_last :
  86                                     rxrpc_transmit_rotate));
  87         wake_up(&call->waitq);
  88
  89         while (list) {
  90                 skb = list;
  91                 list = skb->next;
  92                 skb->next = NULL;
  93                 rxrpc_free_skb(skb, rxrpc_skb_tx_freed);
  94         }
  95 }
  96
  97 /*
  98  * End the transmission phase of a call.
  99  *
 100  * This occurs when we get an ACKALL packet, the first DATA packet of a reply,
 101  * or a final ACK packet.
 102  */
 103 static bool rxrpc_end_tx_phase(struct rxrpc_call *call, bool reply_begun,
 104                                const char *abort_why)
 105 {
 106
 107         ASSERT(test_bit(RXRPC_CALL_TX_LAST, &call->flags));
 108
 109         write_lock(&call->state_lock);
 110
 111         switch (call->state) {
 112         case RXRPC_CALL_CLIENT_SEND_REQUEST:
 113         case RXRPC_CALL_CLIENT_AWAIT_REPLY:
 114                 if (reply_begun)
 115                         call->state = RXRPC_CALL_CLIENT_RECV_REPLY;
 116                 else
 117                         call->state = RXRPC_CALL_CLIENT_AWAIT_REPLY;
 118                 break;
 119
 120         case RXRPC_CALL_SERVER_AWAIT_ACK:
 121                 __rxrpc_call_completed(call);
 122                 rxrpc_notify_socket(call);
 123                 break;
 124
 125         default:
 126                 goto bad_state;
 127         }
 128
 129         write_unlock(&call->state_lock);
 130         if (call->state == RXRPC_CALL_CLIENT_AWAIT_REPLY) {
 131                 trace_rxrpc_transmit(call, rxrpc_transmit_await_reply);
 132         } else {
 133                 trace_rxrpc_transmit(call, rxrpc_transmit_end);
 134         }
 135         _leave(" = ok");
 136         return true;
 137
 138 bad_state:
 139         write_unlock(&call->state_lock);
 140         kdebug("end_tx %s", rxrpc_call_states[call->state]);
 141         rxrpc_proto_abort(abort_why, call, call->tx_top);
 142         return false;
 143 }
 144
 145 /*
 146  * Begin the reply reception phase of a call.
 147  */
 148 static bool rxrpc_receiving_reply(struct rxrpc_call *call)
 149 {
 150         rxrpc_seq_t top = READ_ONCE(call->tx_top);
 151
 152         if (!test_bit(RXRPC_CALL_TX_LAST, &call->flags))
 153                 rxrpc_rotate_tx_window(call, top);
 154         if (!test_bit(RXRPC_CALL_TX_LAST, &call->flags)) {
 155                 rxrpc_proto_abort("TXL", call, top);
 156                 return false;
 157         }
 158         if (!rxrpc_end_tx_phase(call, true, "ETD"))
 159                 return false;
 160         call->tx_phase = false;
 161         return true;
 162 }
 163
 164 /*
 165  * Scan a jumbo packet to validate its structure and to work out how many
 166  * subpackets it contains.
 167  *
 168  * A jumbo packet is a collection of consecutive packets glued together with
 169  * little headers between that indicate how to change the initial header for
 170  * each subpacket.
 171  *
 172  * RXRPC_JUMBO_PACKET must be set on all but the last subpacket - and all but
 173  * the last are RXRPC_JUMBO_DATALEN in size.  The last subpacket may be of any
 174  * size.
 175  */
 176 static bool rxrpc_validate_jumbo(struct sk_buff *skb)
 177 {
 178         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 179         unsigned int offset = sp->offset;
 180         unsigned int len = skb->len;
 181         int nr_jumbo = 1;
 182         u8 flags = sp->hdr.flags;
 183
 184         do {
 185                 nr_jumbo++;
 186                 if (len - offset < RXRPC_JUMBO_SUBPKTLEN)
 187                         goto protocol_error;
 188                 if (flags & RXRPC_LAST_PACKET)
 189                         goto protocol_error;
 190                 offset += RXRPC_JUMBO_DATALEN;
 191                 if (skb_copy_bits(skb, offset, &flags, 1) < 0)
 192                         goto protocol_error;
 193                 offset += sizeof(struct rxrpc_jumbo_header);
 194         } while (flags & RXRPC_JUMBO_PACKET);
 195
 196         sp->nr_jumbo = nr_jumbo;
 197         return true;
 198
 199 protocol_error:
 200         return false;
 201 }
 202
 203 /*
 204  * Handle reception of a duplicate packet.
 205  *
 206  * We have to take care to avoid an attack here whereby we're given a series of
 207  * jumbograms, each with a sequence number one before the preceding one and
 208  * filled up to maximum UDP size.  If they never send us the first packet in
 209  * the sequence, they can cause us to have to hold on to around 2MiB of kernel
 210  * space until the call times out.
 211  *
 212  * We limit the space usage by only accepting three duplicate jumbo packets per
 213  * call.  After that, we tell the other side we're no longer accepting jumbos
 214  * (that information is encoded in the ACK packet).
 215  */
 216 static void rxrpc_input_dup_data(struct rxrpc_call *call, rxrpc_seq_t seq,
 217                                  u8 annotation, bool *_jumbo_bad)
 218 {
 219         /* Discard normal packets that are duplicates. */
 220         if (annotation == 0)
 221                 return;
 222
 223         /* Skip jumbo subpackets that are duplicates.  When we've had three or
 224          * more partially duplicate jumbo packets, we refuse to take any more
 225          * jumbos for this call.
 226          */
 227         if (!*_jumbo_bad) {
 228                 call->nr_jumbo_bad++;
 229                 *_jumbo_bad = true;
 230         }
 231 }
 232
 233 /*
 234  * Process a DATA packet, adding the packet to the Rx ring.
 235  */
 236 static void rxrpc_input_data(struct rxrpc_call *call, struct sk_buff *skb,
 237                              u16 skew)
 238 {
 239         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 240         unsigned int offset = sp->offset;
 241         unsigned int ix;
 242         rxrpc_serial_t serial = sp->hdr.serial, ack_serial = 0;
 243         rxrpc_seq_t seq = sp->hdr.seq, hard_ack;
 244         bool immediate_ack = false, jumbo_bad = false, queued;
 245         u16 len;
 246         u8 ack = 0, flags, annotation = 0;
 247
 248         _enter("{%u,%u},{%u,%u}",
 249                call->rx_hard_ack, call->rx_top, skb->len, seq);
 250
 251         _proto("Rx DATA %%%u { #%u f=%02x }",
 252                sp->hdr.serial, seq, sp->hdr.flags);
 253
 254         if (call->state >= RXRPC_CALL_COMPLETE)
 255                 return;
 256
 257         /* Received data implicitly ACKs all of the request packets we sent
 258          * when we're acting as a client.
 259          */
 260         if ((call->state == RXRPC_CALL_CLIENT_SEND_REQUEST ||
 261              call->state == RXRPC_CALL_CLIENT_AWAIT_REPLY) &&
 262             !rxrpc_receiving_reply(call))
 263                 return;
 264
 265         call->ackr_prev_seq = seq;
 266
 267         hard_ack = READ_ONCE(call->rx_hard_ack);
 268         if (after(seq, hard_ack + call->rx_winsize)) {
 269                 ack = RXRPC_ACK_EXCEEDS_WINDOW;
 270                 ack_serial = serial;
 271                 goto ack;
 272         }
 273
 274         flags = sp->hdr.flags;
 275         if (flags & RXRPC_JUMBO_PACKET) {
 276                 if (call->nr_jumbo_bad > 3) {
 277                         ack = RXRPC_ACK_NOSPACE;
 278                         ack_serial = serial;
 279                         goto ack;
 280                 }
 281                 annotation = 1;
 282         }
 283
 284 next_subpacket:
 285         queued = false;
 286         ix = seq & RXRPC_RXTX_BUFF_MASK;
 287         len = skb->len;
 288         if (flags & RXRPC_JUMBO_PACKET)
 289                 len = RXRPC_JUMBO_DATALEN;
 290
 291         if (flags & RXRPC_LAST_PACKET) {
 292                 if (test_bit(RXRPC_CALL_RX_LAST, &call->flags) &&
 293                     seq != call->rx_top)
 294                         return rxrpc_proto_abort("LSN", call, seq);
 295         } else {
 296                 if (test_bit(RXRPC_CALL_RX_LAST, &call->flags) &&
 297                     after_eq(seq, call->rx_top))
 298                         return rxrpc_proto_abort("LSA", call, seq);
 299         }
 300
 301         if (before_eq(seq, hard_ack)) {
 302                 ack = RXRPC_ACK_DUPLICATE;
 303                 ack_serial = serial;
 304                 goto skip;
 305         }
 306
 307         if (flags & RXRPC_REQUEST_ACK && !ack) {
 308                 ack = RXRPC_ACK_REQUESTED;
 309                 ack_serial = serial;
 310         }
 311
 312         if (call->rxtx_buffer[ix]) {
 313                 rxrpc_input_dup_data(call, seq, annotation, &jumbo_bad);
 314                 if (ack != RXRPC_ACK_DUPLICATE) {
 315                         ack = RXRPC_ACK_DUPLICATE;
 316                         ack_serial = serial;
 317                 }
 318                 immediate_ack = true;
 319                 goto skip;
 320         }
 321
 322         /* Queue the packet.  We use a couple of memory barriers here as need
 323          * to make sure that rx_top is perceived to be set after the buffer
 324          * pointer and that the buffer pointer is set after the annotation and
 325          * the skb data.
 326          *
 327          * Barriers against rxrpc_recvmsg_data() and rxrpc_rotate_rx_window()
 328          * and also rxrpc_fill_out_ack().
 329          */
 330         rxrpc_get_skb(skb, rxrpc_skb_rx_got);
 331         call->rxtx_annotations[ix] = annotation;
 332         smp_wmb();
 333         call->rxtx_buffer[ix] = skb;
 334         if (after(seq, call->rx_top))
 335                 smp_store_release(&call->rx_top, seq);
 336         if (flags & RXRPC_LAST_PACKET) {
 337                 set_bit(RXRPC_CALL_RX_LAST, &call->flags);
 338                 trace_rxrpc_receive(call, rxrpc_receive_queue_last, serial, seq);
 339         } else {
 340                 trace_rxrpc_receive(call, rxrpc_receive_queue, serial, seq);
 341         }
 342         queued = true;
 343
 344         if (after_eq(seq, call->rx_expect_next)) {
 345                 if (after(seq, call->rx_expect_next)) {
 346                         _net("OOS %u > %u", seq, call->rx_expect_next);
 347                         ack = RXRPC_ACK_OUT_OF_SEQUENCE;
 348                         ack_serial = serial;
 349                 }
 350                 call->rx_expect_next = seq + 1;
 351         }
 352
 353 skip:
 354         offset += len;
 355         if (flags & RXRPC_JUMBO_PACKET) {
 356                 if (skb_copy_bits(skb, offset, &flags, 1) < 0)
 357                         return rxrpc_proto_abort("XJF", call, seq);
 358                 offset += sizeof(struct rxrpc_jumbo_header);
 359                 seq++;
 360                 serial++;
 361                 annotation++;
 362                 if (flags & RXRPC_JUMBO_PACKET)
 363                         annotation |= RXRPC_RX_ANNO_JLAST;
 364                 if (after(seq, hard_ack + call->rx_winsize)) {
 365                         ack = RXRPC_ACK_EXCEEDS_WINDOW;
 366                         ack_serial = serial;
 367                         if (!jumbo_bad) {
 368                                 call->nr_jumbo_bad++;
 369                                 jumbo_bad = true;
 370                         }
 371                         goto ack;
 372                 }
 373
 374                 _proto("Rx DATA Jumbo %%%u", serial);
 375                 goto next_subpacket;
 376         }
 377
 378         if (queued && flags & RXRPC_LAST_PACKET && !ack) {
 379                 ack = RXRPC_ACK_DELAY;
 380                 ack_serial = serial;
 381         }
 382
 383 ack:
 384         if (ack)
 385                 rxrpc_propose_ACK(call, ack, skew, ack_serial,
 386                                   immediate_ack, true,
 387                                   rxrpc_propose_ack_input_data);
 388
 389         if (sp->hdr.seq == READ_ONCE(call->rx_hard_ack) + 1)
 390                 rxrpc_notify_socket(call);
 391         _leave(" [queued]");
 392 }
 393
 394 /*
 395  * Process a requested ACK.
 396  */
 397 static void rxrpc_input_requested_ack(struct rxrpc_call *call,
 398                                       ktime_t resp_time,
 399                                       rxrpc_serial_t orig_serial,
 400                                       rxrpc_serial_t ack_serial)
 401 {
 402         struct rxrpc_skb_priv *sp;
 403         struct sk_buff *skb;
 404         ktime_t sent_at;
 405         int ix;
 406
 407         for (ix = 0; ix < RXRPC_RXTX_BUFF_SIZE; ix++) {
 408                 skb = call->rxtx_buffer[ix];
 409                 if (!skb)
 410                         continue;
 411
 412                 sp = rxrpc_skb(skb);
 413                 if (sp->hdr.serial != orig_serial)
 414                         continue;
 415                 smp_rmb();
 416                 sent_at = skb->tstamp;
 417                 goto found;
 418         }
 419         return;
 420
 421 found:
 422         rxrpc_peer_add_rtt(call, rxrpc_rtt_rx_requested_ack,
 423                            orig_serial, ack_serial, sent_at, resp_time);
 424 }
 425
 426 /*
 427  * Process a ping response.
 428  */
 429 static void rxrpc_input_ping_response(struct rxrpc_call *call,
 430                                       ktime_t resp_time,
 431                                       rxrpc_serial_t orig_serial,
 432                                       rxrpc_serial_t ack_serial)
 433 {
 434         rxrpc_serial_t ping_serial;
 435         ktime_t ping_time;
 436
 437         ping_time = call->ackr_ping_time;
 438         smp_rmb();
 439         ping_serial = call->ackr_ping;
 440
 441         if (!test_bit(RXRPC_CALL_PINGING, &call->flags) ||
 442             before(orig_serial, ping_serial))
 443                 return;
 444         clear_bit(RXRPC_CALL_PINGING, &call->flags);
 445         if (after(orig_serial, ping_serial))
 446                 return;
 447
 448         rxrpc_peer_add_rtt(call, rxrpc_rtt_rx_ping_response,
 449                            orig_serial, ack_serial, ping_time, resp_time);
 450 }
 451
 452 /*
 453  * Process the extra information that may be appended to an ACK packet
 454  */
 455 static void rxrpc_input_ackinfo(struct rxrpc_call *call, struct sk_buff *skb,
 456                                 struct rxrpc_ackinfo *ackinfo)
 457 {
 458         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 459         struct rxrpc_peer *peer;
 460         unsigned int mtu;
 461         u32 rwind = ntohl(ackinfo->rwind);
 462
 463         _proto("Rx ACK %%%u Info { rx=%u max=%u rwin=%u jm=%u }",
 464                sp->hdr.serial,
 465                ntohl(ackinfo->rxMTU), ntohl(ackinfo->maxMTU),
 466                rwind, ntohl(ackinfo->jumbo_max));
 467
 468         if (rwind > RXRPC_RXTX_BUFF_SIZE - 1)
 469                 rwind = RXRPC_RXTX_BUFF_SIZE - 1;
 470         call->tx_winsize = rwind;
 471
 472         mtu = min(ntohl(ackinfo->rxMTU), ntohl(ackinfo->maxMTU));
 473
 474         peer = call->peer;
 475         if (mtu < peer->maxdata) {
 476                 spin_lock_bh(&peer->lock);
 477                 peer->maxdata = mtu;
 478                 peer->mtu = mtu + peer->hdrsize;
 479                 spin_unlock_bh(&peer->lock);
 480                 _net("Net MTU %u (maxdata %u)", peer->mtu, peer->maxdata);
 481         }
 482 }
 483
 484 /*
 485  * Process individual soft ACKs.
 486  *
 487  * Each ACK in the array corresponds to one packet and can be either an ACK or
 488  * a NAK.  If we get find an explicitly NAK'd packet we resend immediately;
 489  * packets that lie beyond the end of the ACK list are scheduled for resend by
 490  * the timer on the basis that the peer might just not have processed them at
 491  * the time the ACK was sent.
 492  */
 493 static void rxrpc_input_soft_acks(struct rxrpc_call *call, u8 *acks,
 494                                   rxrpc_seq_t seq, int nr_acks)
 495 {
 496         bool resend = false;
 497         int ix;
 498         u8 annotation, anno_type;
 499
 500         for (; nr_acks > 0; nr_acks--, seq++) {
 501                 ix = seq & RXRPC_RXTX_BUFF_MASK;
 502                 annotation = call->rxtx_annotations[ix];
 503                 anno_type = annotation & RXRPC_TX_ANNO_MASK;
 504                 annotation &= ~RXRPC_TX_ANNO_MASK;
 505                 switch (*acks++) {
 506                 case RXRPC_ACK_TYPE_ACK:
 507                         if (anno_type == RXRPC_TX_ANNO_ACK)
 508                                 continue;
 509                         call->rxtx_annotations[ix] =
 510                                 RXRPC_TX_ANNO_ACK | annotation;
 511                         break;
 512                 case RXRPC_ACK_TYPE_NACK:
 513                         if (anno_type == RXRPC_TX_ANNO_NAK)
 514                                 continue;
 515                         if (anno_type == RXRPC_TX_ANNO_RETRANS)
 516                                 continue;
 517                         call->rxtx_annotations[ix] =
 518                                 RXRPC_TX_ANNO_NAK | annotation;
 519                         resend = true;
 520                         break;
 521                 default:
 522                         return rxrpc_proto_abort("SFT", call, 0);
 523                 }
 524         }
 525
 526         if (resend &&
 527             !test_and_set_bit(RXRPC_CALL_EV_RESEND, &call->events))
 528                 rxrpc_queue_call(call);
 529 }
 530
 531 /*
 532  * Process an ACK packet.
 533  *
 534  * ack.firstPacket is the sequence number of the first soft-ACK'd/NAK'd packet
 535  * in the ACK array.  Anything before that is hard-ACK'd and may be discarded.
 536  *
 537  * A hard-ACK means that a packet has been processed and may be discarded; a
 538  * soft-ACK means that the packet may be discarded and retransmission
 539  * requested.  A phase is complete when all packets are hard-ACK'd.
 540  */
 541 static void rxrpc_input_ack(struct rxrpc_call *call, struct sk_buff *skb,
 542                             u16 skew)
 543 {
 544         u8 ack_reason;
 545         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 546         union {
 547                 struct rxrpc_ackpacket ack;
 548                 struct rxrpc_ackinfo info;
 549                 u8 acks[RXRPC_MAXACKS];
 550         } buf;
 551         rxrpc_serial_t acked_serial;
 552         rxrpc_seq_t first_soft_ack, hard_ack;
 553         int nr_acks, offset;
 554
 555         _enter("");
 556
 557         if (skb_copy_bits(skb, sp->offset, &buf.ack, sizeof(buf.ack)) < 0) {
 558                 _debug("extraction failure");
 559                 return rxrpc_proto_abort("XAK", call, 0);
 560         }
 561         sp->offset += sizeof(buf.ack);
 562
 563         acked_serial = ntohl(buf.ack.serial);
 564         first_soft_ack = ntohl(buf.ack.firstPacket);
 565         hard_ack = first_soft_ack - 1;
 566         nr_acks = buf.ack.nAcks;
 567         ack_reason = (buf.ack.reason < RXRPC_ACK__INVALID ?
 568                       buf.ack.reason : RXRPC_ACK__INVALID);
 569
 570         trace_rxrpc_rx_ack(call, first_soft_ack, ack_reason, nr_acks);
 571
 572         _proto("Rx ACK %%%u { m=%hu f=#%u p=#%u s=%%%u r=%s n=%u }",
 573                sp->hdr.serial,
 574                ntohs(buf.ack.maxSkew),
 575                first_soft_ack,
 576                ntohl(buf.ack.previousPacket),
 577                acked_serial,
 578                rxrpc_ack_names[ack_reason],
 579                buf.ack.nAcks);
 580
 581         if (buf.ack.reason == RXRPC_ACK_PING_RESPONSE)
 582                 rxrpc_input_ping_response(call, skb->tstamp, acked_serial,
 583                                           sp->hdr.serial);
 584         if (buf.ack.reason == RXRPC_ACK_REQUESTED)
 585                 rxrpc_input_requested_ack(call, skb->tstamp, acked_serial,
 586                                           sp->hdr.serial);
 587
 588         if (buf.ack.reason == RXRPC_ACK_PING) {
 589                 _proto("Rx ACK %%%u PING Request", sp->hdr.serial);
 590                 rxrpc_propose_ACK(call, RXRPC_ACK_PING_RESPONSE,
 591                                   skew, sp->hdr.serial, true, true,
 592                                   rxrpc_propose_ack_respond_to_ping);
 593         } else if (sp->hdr.flags & RXRPC_REQUEST_ACK) {
 594                 rxrpc_propose_ACK(call, RXRPC_ACK_REQUESTED,
 595                                   skew, sp->hdr.serial, true, true,
 596                                   rxrpc_propose_ack_respond_to_ack);
 597         }
 598
 599         offset = sp->offset + nr_acks + 3;
 600         if (skb->len >= offset + sizeof(buf.info)) {
 601                 if (skb_copy_bits(skb, offset, &buf.info, sizeof(buf.info)) < 0)
 602                         return rxrpc_proto_abort("XAI", call, 0);
 603                 rxrpc_input_ackinfo(call, skb, &buf.info);
 604         }
 605
 606         if (first_soft_ack == 0)
 607                 return rxrpc_proto_abort("AK0", call, 0);
 608
 609         /* Ignore ACKs unless we are or have just been transmitting. */
 610         switch (call->state) {
 611         case RXRPC_CALL_CLIENT_SEND_REQUEST:
 612         case RXRPC_CALL_CLIENT_AWAIT_REPLY:
 613         case RXRPC_CALL_SERVER_SEND_REPLY:
 614         case RXRPC_CALL_SERVER_AWAIT_ACK:
 615                 break;
 616         default:
 617                 return;
 618         }
 619
 620         /* Discard any out-of-order or duplicate ACKs. */
 621         if (before_eq(sp->hdr.serial, call->acks_latest)) {
 622                 _debug("discard ACK %d <= %d",
 623                        sp->hdr.serial, call->acks_latest);
 624                 return;
 625         }
 626         call->acks_latest = sp->hdr.serial;
 627
 628         if (before(hard_ack, call->tx_hard_ack) ||
 629             after(hard_ack, call->tx_top))
 630                 return rxrpc_proto_abort("AKW", call, 0);
 631         if (nr_acks > call->tx_top - hard_ack)
 632                 return rxrpc_proto_abort("AKN", call, 0);
 633
 634         if (after(hard_ack, call->tx_hard_ack))
 635                 rxrpc_rotate_tx_window(call, hard_ack);
 636
 637         if (nr_acks > 0) {
 638                 if (skb_copy_bits(skb, sp->offset, buf.acks, nr_acks) < 0)
 639                         return rxrpc_proto_abort("XSA", call, 0);
 640                 rxrpc_input_soft_acks(call, buf.acks, first_soft_ack, nr_acks);
 641         }
 642
 643         if (test_bit(RXRPC_CALL_TX_LAST, &call->flags)) {
 644                 rxrpc_end_tx_phase(call, false, "ETA");
 645                 return;
 646         }
 647
 648 }
 649
 650 /*
 651  * Process an ACKALL packet.
 652  */
 653 static void rxrpc_input_ackall(struct rxrpc_call *call, struct sk_buff *skb)
 654 {
 655         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 656
 657         _proto("Rx ACKALL %%%u", sp->hdr.serial);
 658
 659         rxrpc_rotate_tx_window(call, call->tx_top);
 660         if (test_bit(RXRPC_CALL_TX_LAST, &call->flags))
 661                 rxrpc_end_tx_phase(call, false, "ETL");
 662 }
 663
 664 /*
 665  * Process an ABORT packet.
 666  */
 667 static void rxrpc_input_abort(struct rxrpc_call *call, struct sk_buff *skb)
 668 {
 669         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 670         __be32 wtmp;
 671         u32 abort_code = RX_CALL_DEAD;
 672
 673         _enter("");
 674
 675         if (skb->len >= 4 &&
 676             skb_copy_bits(skb, sp->offset, &wtmp, sizeof(wtmp)) >= 0)
 677                 abort_code = ntohl(wtmp);
 678
 679         _proto("Rx ABORT %%%u { %x }", sp->hdr.serial, abort_code);
 680
 681         if (rxrpc_set_call_completion(call, RXRPC_CALL_REMOTELY_ABORTED,
 682                                       abort_code, ECONNABORTED))
 683                 rxrpc_notify_socket(call);
 684 }
 685
 686 /*
 687  * Process an incoming call packet.
 688  */
 689 static void rxrpc_input_call_packet(struct rxrpc_call *call,
 690                                     struct sk_buff *skb, u16 skew)
 691 {
 692         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 693
 694         _enter("%p,%p", call, skb);
 695
 696         switch (sp->hdr.type) {
 697         case RXRPC_PACKET_TYPE_DATA:
 698                 rxrpc_input_data(call, skb, skew);
 699                 break;
 700
 701         case RXRPC_PACKET_TYPE_ACK:
 702                 rxrpc_input_ack(call, skb, skew);
 703                 break;
 704
 705         case RXRPC_PACKET_TYPE_BUSY:
 706                 _proto("Rx BUSY %%%u", sp->hdr.serial);
 707
 708                 /* Just ignore BUSY packets from the server; the retry and
 709                  * lifespan timers will take care of business.  BUSY packets
 710                  * from the client don't make sense.
 711                  */
 712                 break;
 713
 714         case RXRPC_PACKET_TYPE_ABORT:
 715                 rxrpc_input_abort(call, skb);
 716                 break;
 717
 718         case RXRPC_PACKET_TYPE_ACKALL:
 719                 rxrpc_input_ackall(call, skb);
 720                 break;
 721
 722         default:
 723                 _proto("Rx %s %%%u", rxrpc_pkts[sp->hdr.type], sp->hdr.serial);
 724                 break;
 725         }
 726
 727         _leave("");
 728 }
 729
 730 /*
 731  * post connection-level events to the connection
 732  * - this includes challenges, responses, some aborts and call terminal packet
 733  *   retransmission.
 734  */
 735 static void rxrpc_post_packet_to_conn(struct rxrpc_connection *conn,
 736                                       struct sk_buff *skb)
 737 {
 738         _enter("%p,%p", conn, skb);
 739
 740         skb_queue_tail(&conn->rx_queue, skb);
 741         rxrpc_queue_conn(conn);
 742 }
 743
 744 /*
 745  * post endpoint-level events to the local endpoint
 746  * - this includes debug and version messages
 747  */
 748 static void rxrpc_post_packet_to_local(struct rxrpc_local *local,
 749                                        struct sk_buff *skb)
 750 {
 751         _enter("%p,%p", local, skb);
 752
 753         skb_queue_tail(&local->event_queue, skb);
 754         rxrpc_queue_local(local);
 755 }
 756
 757 /*
 758  * put a packet up for transport-level abort
 759  */
 760 static void rxrpc_reject_packet(struct rxrpc_local *local, struct sk_buff *skb)
 761 {
 762         CHECK_SLAB_OKAY(&local->usage);
 763
 764         skb_queue_tail(&local->reject_queue, skb);
 765         rxrpc_queue_local(local);
 766 }
 767
 768 /*
 769  * Extract the wire header from a packet and translate the byte order.
 770  */
 771 static noinline
 772 int rxrpc_extract_header(struct rxrpc_skb_priv *sp, struct sk_buff *skb)
 773 {
 774         struct rxrpc_wire_header whdr;
 775
 776         /* dig out the RxRPC connection details */
 777         if (skb_copy_bits(skb, 0, &whdr, sizeof(whdr)) < 0)
 778                 return -EBADMSG;
 779
 780         memset(sp, 0, sizeof(*sp));
 781         sp->hdr.epoch           = ntohl(whdr.epoch);
 782         sp->hdr.cid             = ntohl(whdr.cid);
 783         sp->hdr.callNumber      = ntohl(whdr.callNumber);
 784         sp->hdr.seq             = ntohl(whdr.seq);
 785         sp->hdr.serial          = ntohl(whdr.serial);
 786         sp->hdr.flags           = whdr.flags;
 787         sp->hdr.type            = whdr.type;
 788         sp->hdr.userStatus      = whdr.userStatus;
 789         sp->hdr.securityIndex   = whdr.securityIndex;
 790         sp->hdr._rsvd           = ntohs(whdr._rsvd);
 791         sp->hdr.serviceId       = ntohs(whdr.serviceId);
 792         sp->offset = sizeof(whdr);
 793         return 0;
 794 }
 795
 796 /*
 797  * handle data received on the local endpoint
 798  * - may be called in interrupt context
 799  *
 800  * The socket is locked by the caller and this prevents the socket from being
 801  * shut down and the local endpoint from going away, thus sk_user_data will not
 802  * be cleared until this function returns.
 803  */
 804 void rxrpc_data_ready(struct sock *udp_sk)
 805 {
 806         struct rxrpc_connection *conn;
 807         struct rxrpc_channel *chan;
 808         struct rxrpc_call *call;
 809         struct rxrpc_skb_priv *sp;
 810         struct rxrpc_local *local = udp_sk->sk_user_data;
 811         struct sk_buff *skb;
 812         unsigned int channel;
 813         int ret, skew;
 814
 815         _enter("%p", udp_sk);
 816
 817         ASSERT(!irqs_disabled());
 818
 819         skb = skb_recv_datagram(udp_sk, 0, 1, &ret);
 820         if (!skb) {
 821                 if (ret == -EAGAIN)
 822                         return;
 823                 _debug("UDP socket error %d", ret);
 824                 return;
 825         }
 826
 827         rxrpc_new_skb(skb, rxrpc_skb_rx_received);
 828
 829         _net("recv skb %p", skb);
 830
 831         /* we'll probably need to checksum it (didn't call sock_recvmsg) */
 832         if (skb_checksum_complete(skb)) {
 833                 rxrpc_free_skb(skb, rxrpc_skb_rx_freed);
 834                 __UDP_INC_STATS(&init_net, UDP_MIB_INERRORS, 0);
 835                 _leave(" [CSUM failed]");
 836                 return;
 837         }
 838
 839         __UDP_INC_STATS(&init_net, UDP_MIB_INDATAGRAMS, 0);
 840
 841         /* The socket buffer we have is owned by UDP, with UDP's data all over
 842          * it, but we really want our own data there.
 843          */
 844         skb_orphan(skb);
 845         sp = rxrpc_skb(skb);
 846
 847         /* dig out the RxRPC connection details */
 848         if (rxrpc_extract_header(sp, skb) < 0)
 849                 goto bad_message;
 850
 851         if (IS_ENABLED(CONFIG_AF_RXRPC_INJECT_LOSS)) {
 852                 static int lose;
 853                 if ((lose++ & 7) == 7) {
 854                         trace_rxrpc_rx_lose(sp);
 855                         rxrpc_lose_skb(skb, rxrpc_skb_rx_lost);
 856                         return;
 857                 }
 858         }
 859
 860         trace_rxrpc_rx_packet(sp);
 861
 862         _net("Rx RxRPC %s ep=%x call=%x:%x",
 863              sp->hdr.flags & RXRPC_CLIENT_INITIATED ? "ToServer" : "ToClient",
 864              sp->hdr.epoch, sp->hdr.cid, sp->hdr.callNumber);
 865
 866         if (sp->hdr.type >= RXRPC_N_PACKET_TYPES ||
 867             !((RXRPC_SUPPORTED_PACKET_TYPES >> sp->hdr.type) & 1)) {
 868                 _proto("Rx Bad Packet Type %u", sp->hdr.type);
 869                 goto bad_message;
 870         }
 871
 872         switch (sp->hdr.type) {
 873         case RXRPC_PACKET_TYPE_VERSION:
 874                 rxrpc_post_packet_to_local(local, skb);
 875                 goto out;
 876
 877         case RXRPC_PACKET_TYPE_BUSY:
 878                 if (sp->hdr.flags & RXRPC_CLIENT_INITIATED)
 879                         goto discard;
 880
 881         case RXRPC_PACKET_TYPE_DATA:
 882                 if (sp->hdr.callNumber == 0)
 883                         goto bad_message;
 884                 if (sp->hdr.flags & RXRPC_JUMBO_PACKET &&
 885                     !rxrpc_validate_jumbo(skb))
 886                         goto bad_message;
 887                 break;
 888         }
 889
 890         rcu_read_lock();
 891
 892         conn = rxrpc_find_connection_rcu(local, skb);
 893         if (conn) {
 894                 if (sp->hdr.securityIndex != conn->security_ix)
 895                         goto wrong_security;
 896
 897                 if (sp->hdr.callNumber == 0) {
 898                         /* Connection-level packet */
 899                         _debug("CONN %p {%d}", conn, conn->debug_id);
 900                         rxrpc_post_packet_to_conn(conn, skb);
 901                         goto out_unlock;
 902                 }
 903
 904                 /* Note the serial number skew here */
 905                 skew = (int)sp->hdr.serial - (int)conn->hi_serial;
 906                 if (skew >= 0) {
 907                         if (skew > 0)
 908                                 conn->hi_serial = sp->hdr.serial;
 909                 } else {
 910                         skew = -skew;
 911                         skew = min(skew, 65535);
 912                 }
 913
 914                 /* Call-bound packets are routed by connection channel. */
 915                 channel = sp->hdr.cid & RXRPC_CHANNELMASK;
 916                 chan = &conn->channels[channel];
 917
 918                 /* Ignore really old calls */
 919                 if (sp->hdr.callNumber < chan->last_call)
 920                         goto discard_unlock;
 921
 922                 if (sp->hdr.callNumber == chan->last_call) {
 923                         /* For the previous service call, if completed successfully, we
 924                          * discard all further packets.
 925                          */
 926                         if (rxrpc_conn_is_service(conn) &&
 927                             (chan->last_type == RXRPC_PACKET_TYPE_ACK ||
 928                              sp->hdr.type == RXRPC_PACKET_TYPE_ABORT))
 929                                 goto discard_unlock;
 930
 931                         /* But otherwise we need to retransmit the final packet from
 932                          * data cached in the connection record.
 933                          */
 934                         rxrpc_post_packet_to_conn(conn, skb);
 935                         goto out_unlock;
 936                 }
 937
 938                 call = rcu_dereference(chan->call);
 939         } else {
 940                 skew = 0;
 941                 call = NULL;
 942         }
 943
 944         if (!call || atomic_read(&call->usage) == 0) {
 945                 if (!(sp->hdr.type & RXRPC_CLIENT_INITIATED) ||
 946                     sp->hdr.callNumber == 0 ||
 947                     sp->hdr.type != RXRPC_PACKET_TYPE_DATA)
 948                         goto bad_message_unlock;
 949                 if (sp->hdr.seq != 1)
 950                         goto discard_unlock;
 951                 call = rxrpc_new_incoming_call(local, conn, skb);
 952                 if (!call) {
 953                         rcu_read_unlock();
 954                         goto reject_packet;
 955                 }
 956                 rxrpc_send_ping(call, skb, skew);
 957         }
 958
 959         rxrpc_input_call_packet(call, skb, skew);
 960         goto discard_unlock;
 961
 962 discard_unlock:
 963         rcu_read_unlock();
 964 discard:
 965         rxrpc_free_skb(skb, rxrpc_skb_rx_freed);
 966 out:
 967         trace_rxrpc_rx_done(0, 0);
 968         return;
 969
 970 out_unlock:
 971         rcu_read_unlock();
 972         goto out;
 973
 974 wrong_security:
 975         rcu_read_unlock();
 976         trace_rxrpc_abort("SEC", sp->hdr.cid, sp->hdr.callNumber, sp->hdr.seq,
 977                           RXKADINCONSISTENCY, EBADMSG);
 978         skb->priority = RXKADINCONSISTENCY;
 979         goto post_abort;
 980
 981 bad_message_unlock:
 982         rcu_read_unlock();
 983 bad_message:
 984         trace_rxrpc_abort("BAD", sp->hdr.cid, sp->hdr.callNumber, sp->hdr.seq,
 985                           RX_PROTOCOL_ERROR, EBADMSG);
 986         skb->priority = RX_PROTOCOL_ERROR;
 987 post_abort:
 988         skb->mark = RXRPC_SKB_MARK_LOCAL_ABORT;
 989 reject_packet:
 990         trace_rxrpc_rx_done(skb->mark, skb->priority);
 991         rxrpc_reject_packet(local, skb);
 992         _leave(" [badmsg]");
 993 }