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         } else if (before(seq, call->rx_top)) {
 337                 /* Send an immediate ACK if we fill in a hole */
 338                 if (!ack) {
 339                         ack = RXRPC_ACK_DELAY;
 340                         ack_serial = serial;
 341                 }
 342                 immediate_ack = true;
 343         }
 344         if (flags & RXRPC_LAST_PACKET) {
 345                 set_bit(RXRPC_CALL_RX_LAST, &call->flags);
 346                 trace_rxrpc_receive(call, rxrpc_receive_queue_last, serial, seq);
 347         } else {
 348                 trace_rxrpc_receive(call, rxrpc_receive_queue, serial, seq);
 349         }
 350         queued = true;
 351
 352         if (after_eq(seq, call->rx_expect_next)) {
 353                 if (after(seq, call->rx_expect_next)) {
 354                         _net("OOS %u > %u", seq, call->rx_expect_next);
 355                         ack = RXRPC_ACK_OUT_OF_SEQUENCE;
 356                         ack_serial = serial;
 357                 }
 358                 call->rx_expect_next = seq + 1;
 359         }
 360
 361 skip:
 362         offset += len;
 363         if (flags & RXRPC_JUMBO_PACKET) {
 364                 if (skb_copy_bits(skb, offset, &flags, 1) < 0)
 365                         return rxrpc_proto_abort("XJF", call, seq);
 366                 offset += sizeof(struct rxrpc_jumbo_header);
 367                 seq++;
 368                 serial++;
 369                 annotation++;
 370                 if (flags & RXRPC_JUMBO_PACKET)
 371                         annotation |= RXRPC_RX_ANNO_JLAST;
 372                 if (after(seq, hard_ack + call->rx_winsize)) {
 373                         ack = RXRPC_ACK_EXCEEDS_WINDOW;
 374                         ack_serial = serial;
 375                         if (!jumbo_bad) {
 376                                 call->nr_jumbo_bad++;
 377                                 jumbo_bad = true;
 378                         }
 379                         goto ack;
 380                 }
 381
 382                 _proto("Rx DATA Jumbo %%%u", serial);
 383                 goto next_subpacket;
 384         }
 385
 386         if (queued && flags & RXRPC_LAST_PACKET && !ack) {
 387                 ack = RXRPC_ACK_DELAY;
 388                 ack_serial = serial;
 389         }
 390
 391 ack:
 392         if (ack)
 393                 rxrpc_propose_ACK(call, ack, skew, ack_serial,
 394                                   immediate_ack, true,
 395                                   rxrpc_propose_ack_input_data);
 396
 397         if (sp->hdr.seq == READ_ONCE(call->rx_hard_ack) + 1)
 398                 rxrpc_notify_socket(call);
 399         _leave(" [queued]");
 400 }
 401
 402 /*
 403  * Process a requested ACK.
 404  */
 405 static void rxrpc_input_requested_ack(struct rxrpc_call *call,
 406                                       ktime_t resp_time,
 407                                       rxrpc_serial_t orig_serial,
 408                                       rxrpc_serial_t ack_serial)
 409 {
 410         struct rxrpc_skb_priv *sp;
 411         struct sk_buff *skb;
 412         ktime_t sent_at;
 413         int ix;
 414
 415         for (ix = 0; ix < RXRPC_RXTX_BUFF_SIZE; ix++) {
 416                 skb = call->rxtx_buffer[ix];
 417                 if (!skb)
 418                         continue;
 419
 420                 sp = rxrpc_skb(skb);
 421                 if (sp->hdr.serial != orig_serial)
 422                         continue;
 423                 smp_rmb();
 424                 sent_at = skb->tstamp;
 425                 goto found;
 426         }
 427         return;
 428
 429 found:
 430         rxrpc_peer_add_rtt(call, rxrpc_rtt_rx_requested_ack,
 431                            orig_serial, ack_serial, sent_at, resp_time);
 432 }
 433
 434 /*
 435  * Process a ping response.
 436  */
 437 static void rxrpc_input_ping_response(struct rxrpc_call *call,
 438                                       ktime_t resp_time,
 439                                       rxrpc_serial_t orig_serial,
 440                                       rxrpc_serial_t ack_serial)
 441 {
 442         rxrpc_serial_t ping_serial;
 443         ktime_t ping_time;
 444
 445         ping_time = call->ackr_ping_time;
 446         smp_rmb();
 447         ping_serial = call->ackr_ping;
 448
 449         if (!test_bit(RXRPC_CALL_PINGING, &call->flags) ||
 450             before(orig_serial, ping_serial))
 451                 return;
 452         clear_bit(RXRPC_CALL_PINGING, &call->flags);
 453         if (after(orig_serial, ping_serial))
 454                 return;
 455
 456         rxrpc_peer_add_rtt(call, rxrpc_rtt_rx_ping_response,
 457                            orig_serial, ack_serial, ping_time, resp_time);
 458 }
 459
 460 /*
 461  * Process the extra information that may be appended to an ACK packet
 462  */
 463 static void rxrpc_input_ackinfo(struct rxrpc_call *call, struct sk_buff *skb,
 464                                 struct rxrpc_ackinfo *ackinfo)
 465 {
 466         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 467         struct rxrpc_peer *peer;
 468         unsigned int mtu;
 469         u32 rwind = ntohl(ackinfo->rwind);
 470
 471         _proto("Rx ACK %%%u Info { rx=%u max=%u rwin=%u jm=%u }",
 472                sp->hdr.serial,
 473                ntohl(ackinfo->rxMTU), ntohl(ackinfo->maxMTU),
 474                rwind, ntohl(ackinfo->jumbo_max));
 475
 476         if (rwind > RXRPC_RXTX_BUFF_SIZE - 1)
 477                 rwind = RXRPC_RXTX_BUFF_SIZE - 1;
 478         call->tx_winsize = rwind;
 479
 480         mtu = min(ntohl(ackinfo->rxMTU), ntohl(ackinfo->maxMTU));
 481
 482         peer = call->peer;
 483         if (mtu < peer->maxdata) {
 484                 spin_lock_bh(&peer->lock);
 485                 peer->maxdata = mtu;
 486                 peer->mtu = mtu + peer->hdrsize;
 487                 spin_unlock_bh(&peer->lock);
 488                 _net("Net MTU %u (maxdata %u)", peer->mtu, peer->maxdata);
 489         }
 490 }
 491
 492 /*
 493  * Process individual soft ACKs.
 494  *
 495  * Each ACK in the array corresponds to one packet and can be either an ACK or
 496  * a NAK.  If we get find an explicitly NAK'd packet we resend immediately;
 497  * packets that lie beyond the end of the ACK list are scheduled for resend by
 498  * the timer on the basis that the peer might just not have processed them at
 499  * the time the ACK was sent.
 500  */
 501 static void rxrpc_input_soft_acks(struct rxrpc_call *call, u8 *acks,
 502                                   rxrpc_seq_t seq, int nr_acks)
 503 {
 504         bool resend = false;
 505         int ix;
 506         u8 annotation, anno_type;
 507
 508         for (; nr_acks > 0; nr_acks--, seq++) {
 509                 ix = seq & RXRPC_RXTX_BUFF_MASK;
 510                 annotation = call->rxtx_annotations[ix];
 511                 anno_type = annotation & RXRPC_TX_ANNO_MASK;
 512                 annotation &= ~RXRPC_TX_ANNO_MASK;
 513                 switch (*acks++) {
 514                 case RXRPC_ACK_TYPE_ACK:
 515                         if (anno_type == RXRPC_TX_ANNO_ACK)
 516                                 continue;
 517                         call->rxtx_annotations[ix] =
 518                                 RXRPC_TX_ANNO_ACK | annotation;
 519                         break;
 520                 case RXRPC_ACK_TYPE_NACK:
 521                         if (anno_type == RXRPC_TX_ANNO_NAK)
 522                                 continue;
 523                         if (anno_type == RXRPC_TX_ANNO_RETRANS)
 524                                 continue;
 525                         call->rxtx_annotations[ix] =
 526                                 RXRPC_TX_ANNO_NAK | annotation;
 527                         resend = true;
 528                         break;
 529                 default:
 530                         return rxrpc_proto_abort("SFT", call, 0);
 531                 }
 532         }
 533
 534         if (resend &&
 535             !test_and_set_bit(RXRPC_CALL_EV_RESEND, &call->events))
 536                 rxrpc_queue_call(call);
 537 }
 538
 539 /*
 540  * Process an ACK packet.
 541  *
 542  * ack.firstPacket is the sequence number of the first soft-ACK'd/NAK'd packet
 543  * in the ACK array.  Anything before that is hard-ACK'd and may be discarded.
 544  *
 545  * A hard-ACK means that a packet has been processed and may be discarded; a
 546  * soft-ACK means that the packet may be discarded and retransmission
 547  * requested.  A phase is complete when all packets are hard-ACK'd.
 548  */
 549 static void rxrpc_input_ack(struct rxrpc_call *call, struct sk_buff *skb,
 550                             u16 skew)
 551 {
 552         u8 ack_reason;
 553         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 554         union {
 555                 struct rxrpc_ackpacket ack;
 556                 struct rxrpc_ackinfo info;
 557                 u8 acks[RXRPC_MAXACKS];
 558         } buf;
 559         rxrpc_serial_t acked_serial;
 560         rxrpc_seq_t first_soft_ack, hard_ack;
 561         int nr_acks, offset;
 562
 563         _enter("");
 564
 565         if (skb_copy_bits(skb, sp->offset, &buf.ack, sizeof(buf.ack)) < 0) {
 566                 _debug("extraction failure");
 567                 return rxrpc_proto_abort("XAK", call, 0);
 568         }
 569         sp->offset += sizeof(buf.ack);
 570
 571         acked_serial = ntohl(buf.ack.serial);
 572         first_soft_ack = ntohl(buf.ack.firstPacket);
 573         hard_ack = first_soft_ack - 1;
 574         nr_acks = buf.ack.nAcks;
 575         ack_reason = (buf.ack.reason < RXRPC_ACK__INVALID ?
 576                       buf.ack.reason : RXRPC_ACK__INVALID);
 577
 578         trace_rxrpc_rx_ack(call, first_soft_ack, ack_reason, nr_acks);
 579
 580         _proto("Rx ACK %%%u { m=%hu f=#%u p=#%u s=%%%u r=%s n=%u }",
 581                sp->hdr.serial,
 582                ntohs(buf.ack.maxSkew),
 583                first_soft_ack,
 584                ntohl(buf.ack.previousPacket),
 585                acked_serial,
 586                rxrpc_ack_names[ack_reason],
 587                buf.ack.nAcks);
 588
 589         if (buf.ack.reason == RXRPC_ACK_PING_RESPONSE)
 590                 rxrpc_input_ping_response(call, skb->tstamp, acked_serial,
 591                                           sp->hdr.serial);
 592         if (buf.ack.reason == RXRPC_ACK_REQUESTED)
 593                 rxrpc_input_requested_ack(call, skb->tstamp, acked_serial,
 594                                           sp->hdr.serial);
 595
 596         if (buf.ack.reason == RXRPC_ACK_PING) {
 597                 _proto("Rx ACK %%%u PING Request", sp->hdr.serial);
 598                 rxrpc_propose_ACK(call, RXRPC_ACK_PING_RESPONSE,
 599                                   skew, sp->hdr.serial, true, true,
 600                                   rxrpc_propose_ack_respond_to_ping);
 601         } else if (sp->hdr.flags & RXRPC_REQUEST_ACK) {
 602                 rxrpc_propose_ACK(call, RXRPC_ACK_REQUESTED,
 603                                   skew, sp->hdr.serial, true, true,
 604                                   rxrpc_propose_ack_respond_to_ack);
 605         }
 606
 607         offset = sp->offset + nr_acks + 3;
 608         if (skb->len >= offset + sizeof(buf.info)) {
 609                 if (skb_copy_bits(skb, offset, &buf.info, sizeof(buf.info)) < 0)
 610                         return rxrpc_proto_abort("XAI", call, 0);
 611                 rxrpc_input_ackinfo(call, skb, &buf.info);
 612         }
 613
 614         if (first_soft_ack == 0)
 615                 return rxrpc_proto_abort("AK0", call, 0);
 616
 617         /* Ignore ACKs unless we are or have just been transmitting. */
 618         switch (call->state) {
 619         case RXRPC_CALL_CLIENT_SEND_REQUEST:
 620         case RXRPC_CALL_CLIENT_AWAIT_REPLY:
 621         case RXRPC_CALL_SERVER_SEND_REPLY:
 622         case RXRPC_CALL_SERVER_AWAIT_ACK:
 623                 break;
 624         default:
 625                 return;
 626         }
 627
 628         /* Discard any out-of-order or duplicate ACKs. */
 629         if (before_eq(sp->hdr.serial, call->acks_latest)) {
 630                 _debug("discard ACK %d <= %d",
 631                        sp->hdr.serial, call->acks_latest);
 632                 return;
 633         }
 634         call->acks_latest = sp->hdr.serial;
 635
 636         if (before(hard_ack, call->tx_hard_ack) ||
 637             after(hard_ack, call->tx_top))
 638                 return rxrpc_proto_abort("AKW", call, 0);
 639         if (nr_acks > call->tx_top - hard_ack)
 640                 return rxrpc_proto_abort("AKN", call, 0);
 641
 642         if (after(hard_ack, call->tx_hard_ack))
 643                 rxrpc_rotate_tx_window(call, hard_ack);
 644
 645         if (nr_acks > 0) {
 646                 if (skb_copy_bits(skb, sp->offset, buf.acks, nr_acks) < 0)
 647                         return rxrpc_proto_abort("XSA", call, 0);
 648                 rxrpc_input_soft_acks(call, buf.acks, first_soft_ack, nr_acks);
 649         }
 650
 651         if (test_bit(RXRPC_CALL_TX_LAST, &call->flags)) {
 652                 rxrpc_end_tx_phase(call, false, "ETA");
 653                 return;
 654         }
 655
 656 }
 657
 658 /*
 659  * Process an ACKALL packet.
 660  */
 661 static void rxrpc_input_ackall(struct rxrpc_call *call, struct sk_buff *skb)
 662 {
 663         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 664
 665         _proto("Rx ACKALL %%%u", sp->hdr.serial);
 666
 667         rxrpc_rotate_tx_window(call, call->tx_top);
 668         if (test_bit(RXRPC_CALL_TX_LAST, &call->flags))
 669                 rxrpc_end_tx_phase(call, false, "ETL");
 670 }
 671
 672 /*
 673  * Process an ABORT packet.
 674  */
 675 static void rxrpc_input_abort(struct rxrpc_call *call, struct sk_buff *skb)
 676 {
 677         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 678         __be32 wtmp;
 679         u32 abort_code = RX_CALL_DEAD;
 680
 681         _enter("");
 682
 683         if (skb->len >= 4 &&
 684             skb_copy_bits(skb, sp->offset, &wtmp, sizeof(wtmp)) >= 0)
 685                 abort_code = ntohl(wtmp);
 686
 687         _proto("Rx ABORT %%%u { %x }", sp->hdr.serial, abort_code);
 688
 689         if (rxrpc_set_call_completion(call, RXRPC_CALL_REMOTELY_ABORTED,
 690                                       abort_code, ECONNABORTED))
 691                 rxrpc_notify_socket(call);
 692 }
 693
 694 /*
 695  * Process an incoming call packet.
 696  */
 697 static void rxrpc_input_call_packet(struct rxrpc_call *call,
 698                                     struct sk_buff *skb, u16 skew)
 699 {
 700         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 701
 702         _enter("%p,%p", call, skb);
 703
 704         switch (sp->hdr.type) {
 705         case RXRPC_PACKET_TYPE_DATA:
 706                 rxrpc_input_data(call, skb, skew);
 707                 break;
 708
 709         case RXRPC_PACKET_TYPE_ACK:
 710                 rxrpc_input_ack(call, skb, skew);
 711                 break;
 712
 713         case RXRPC_PACKET_TYPE_BUSY:
 714                 _proto("Rx BUSY %%%u", sp->hdr.serial);
 715
 716                 /* Just ignore BUSY packets from the server; the retry and
 717                  * lifespan timers will take care of business.  BUSY packets
 718                  * from the client don't make sense.
 719                  */
 720                 break;
 721
 722         case RXRPC_PACKET_TYPE_ABORT:
 723                 rxrpc_input_abort(call, skb);
 724                 break;
 725
 726         case RXRPC_PACKET_TYPE_ACKALL:
 727                 rxrpc_input_ackall(call, skb);
 728                 break;
 729
 730         default:
 731                 _proto("Rx %s %%%u", rxrpc_pkts[sp->hdr.type], sp->hdr.serial);
 732                 break;
 733         }
 734
 735         _leave("");
 736 }
 737
 738 /*
 739  * post connection-level events to the connection
 740  * - this includes challenges, responses, some aborts and call terminal packet
 741  *   retransmission.
 742  */
 743 static void rxrpc_post_packet_to_conn(struct rxrpc_connection *conn,
 744                                       struct sk_buff *skb)
 745 {
 746         _enter("%p,%p", conn, skb);
 747
 748         skb_queue_tail(&conn->rx_queue, skb);
 749         rxrpc_queue_conn(conn);
 750 }
 751
 752 /*
 753  * post endpoint-level events to the local endpoint
 754  * - this includes debug and version messages
 755  */
 756 static void rxrpc_post_packet_to_local(struct rxrpc_local *local,
 757                                        struct sk_buff *skb)
 758 {
 759         _enter("%p,%p", local, skb);
 760
 761         skb_queue_tail(&local->event_queue, skb);
 762         rxrpc_queue_local(local);
 763 }
 764
 765 /*
 766  * put a packet up for transport-level abort
 767  */
 768 static void rxrpc_reject_packet(struct rxrpc_local *local, struct sk_buff *skb)
 769 {
 770         CHECK_SLAB_OKAY(&local->usage);
 771
 772         skb_queue_tail(&local->reject_queue, skb);
 773         rxrpc_queue_local(local);
 774 }
 775
 776 /*
 777  * Extract the wire header from a packet and translate the byte order.
 778  */
 779 static noinline
 780 int rxrpc_extract_header(struct rxrpc_skb_priv *sp, struct sk_buff *skb)
 781 {
 782         struct rxrpc_wire_header whdr;
 783
 784         /* dig out the RxRPC connection details */
 785         if (skb_copy_bits(skb, 0, &whdr, sizeof(whdr)) < 0)
 786                 return -EBADMSG;
 787
 788         memset(sp, 0, sizeof(*sp));
 789         sp->hdr.epoch           = ntohl(whdr.epoch);
 790         sp->hdr.cid             = ntohl(whdr.cid);
 791         sp->hdr.callNumber      = ntohl(whdr.callNumber);
 792         sp->hdr.seq             = ntohl(whdr.seq);
 793         sp->hdr.serial          = ntohl(whdr.serial);
 794         sp->hdr.flags           = whdr.flags;
 795         sp->hdr.type            = whdr.type;
 796         sp->hdr.userStatus      = whdr.userStatus;
 797         sp->hdr.securityIndex   = whdr.securityIndex;
 798         sp->hdr._rsvd           = ntohs(whdr._rsvd);
 799         sp->hdr.serviceId       = ntohs(whdr.serviceId);
 800         sp->offset = sizeof(whdr);
 801         return 0;
 802 }
 803
 804 /*
 805  * handle data received on the local endpoint
 806  * - may be called in interrupt context
 807  *
 808  * The socket is locked by the caller and this prevents the socket from being
 809  * shut down and the local endpoint from going away, thus sk_user_data will not
 810  * be cleared until this function returns.
 811  */
 812 void rxrpc_data_ready(struct sock *udp_sk)
 813 {
 814         struct rxrpc_connection *conn;
 815         struct rxrpc_channel *chan;
 816         struct rxrpc_call *call;
 817         struct rxrpc_skb_priv *sp;
 818         struct rxrpc_local *local = udp_sk->sk_user_data;
 819         struct sk_buff *skb;
 820         unsigned int channel;
 821         int ret, skew;
 822
 823         _enter("%p", udp_sk);
 824
 825         ASSERT(!irqs_disabled());
 826
 827         skb = skb_recv_datagram(udp_sk, 0, 1, &ret);
 828         if (!skb) {
 829                 if (ret == -EAGAIN)
 830                         return;
 831                 _debug("UDP socket error %d", ret);
 832                 return;
 833         }
 834
 835         rxrpc_new_skb(skb, rxrpc_skb_rx_received);
 836
 837         _net("recv skb %p", skb);
 838
 839         /* we'll probably need to checksum it (didn't call sock_recvmsg) */
 840         if (skb_checksum_complete(skb)) {
 841                 rxrpc_free_skb(skb, rxrpc_skb_rx_freed);
 842                 __UDP_INC_STATS(&init_net, UDP_MIB_INERRORS, 0);
 843                 _leave(" [CSUM failed]");
 844                 return;
 845         }
 846
 847         __UDP_INC_STATS(&init_net, UDP_MIB_INDATAGRAMS, 0);
 848
 849         /* The socket buffer we have is owned by UDP, with UDP's data all over
 850          * it, but we really want our own data there.
 851          */
 852         skb_orphan(skb);
 853         sp = rxrpc_skb(skb);
 854
 855         /* dig out the RxRPC connection details */
 856         if (rxrpc_extract_header(sp, skb) < 0)
 857                 goto bad_message;
 858
 859         if (IS_ENABLED(CONFIG_AF_RXRPC_INJECT_LOSS)) {
 860                 static int lose;
 861                 if ((lose++ & 7) == 7) {
 862                         trace_rxrpc_rx_lose(sp);
 863                         rxrpc_lose_skb(skb, rxrpc_skb_rx_lost);
 864                         return;
 865                 }
 866         }
 867
 868         trace_rxrpc_rx_packet(sp);
 869
 870         _net("Rx RxRPC %s ep=%x call=%x:%x",
 871              sp->hdr.flags & RXRPC_CLIENT_INITIATED ? "ToServer" : "ToClient",
 872              sp->hdr.epoch, sp->hdr.cid, sp->hdr.callNumber);
 873
 874         if (sp->hdr.type >= RXRPC_N_PACKET_TYPES ||
 875             !((RXRPC_SUPPORTED_PACKET_TYPES >> sp->hdr.type) & 1)) {
 876                 _proto("Rx Bad Packet Type %u", sp->hdr.type);
 877                 goto bad_message;
 878         }
 879
 880         switch (sp->hdr.type) {
 881         case RXRPC_PACKET_TYPE_VERSION:
 882                 rxrpc_post_packet_to_local(local, skb);
 883                 goto out;
 884
 885         case RXRPC_PACKET_TYPE_BUSY:
 886                 if (sp->hdr.flags & RXRPC_CLIENT_INITIATED)
 887                         goto discard;
 888
 889         case RXRPC_PACKET_TYPE_DATA:
 890                 if (sp->hdr.callNumber == 0)
 891                         goto bad_message;
 892                 if (sp->hdr.flags & RXRPC_JUMBO_PACKET &&
 893                     !rxrpc_validate_jumbo(skb))
 894                         goto bad_message;
 895                 break;
 896         }
 897
 898         rcu_read_lock();
 899
 900         conn = rxrpc_find_connection_rcu(local, skb);
 901         if (conn) {
 902                 if (sp->hdr.securityIndex != conn->security_ix)
 903                         goto wrong_security;
 904
 905                 if (sp->hdr.callNumber == 0) {
 906                         /* Connection-level packet */
 907                         _debug("CONN %p {%d}", conn, conn->debug_id);
 908                         rxrpc_post_packet_to_conn(conn, skb);
 909                         goto out_unlock;
 910                 }
 911
 912                 /* Note the serial number skew here */
 913                 skew = (int)sp->hdr.serial - (int)conn->hi_serial;
 914                 if (skew >= 0) {
 915                         if (skew > 0)
 916                                 conn->hi_serial = sp->hdr.serial;
 917                 } else {
 918                         skew = -skew;
 919                         skew = min(skew, 65535);
 920                 }
 921
 922                 /* Call-bound packets are routed by connection channel. */
 923                 channel = sp->hdr.cid & RXRPC_CHANNELMASK;
 924                 chan = &conn->channels[channel];
 925
 926                 /* Ignore really old calls */
 927                 if (sp->hdr.callNumber < chan->last_call)
 928                         goto discard_unlock;
 929
 930                 if (sp->hdr.callNumber == chan->last_call) {
 931                         /* For the previous service call, if completed successfully, we
 932                          * discard all further packets.
 933                          */
 934                         if (rxrpc_conn_is_service(conn) &&
 935                             (chan->last_type == RXRPC_PACKET_TYPE_ACK ||
 936                              sp->hdr.type == RXRPC_PACKET_TYPE_ABORT))
 937                                 goto discard_unlock;
 938
 939                         /* But otherwise we need to retransmit the final packet from
 940                          * data cached in the connection record.
 941                          */
 942                         rxrpc_post_packet_to_conn(conn, skb);
 943                         goto out_unlock;
 944                 }
 945
 946                 call = rcu_dereference(chan->call);
 947         } else {
 948                 skew = 0;
 949                 call = NULL;
 950         }
 951
 952         if (!call || atomic_read(&call->usage) == 0) {
 953                 if (!(sp->hdr.type & RXRPC_CLIENT_INITIATED) ||
 954                     sp->hdr.callNumber == 0 ||
 955                     sp->hdr.type != RXRPC_PACKET_TYPE_DATA)
 956                         goto bad_message_unlock;
 957                 if (sp->hdr.seq != 1)
 958                         goto discard_unlock;
 959                 call = rxrpc_new_incoming_call(local, conn, skb);
 960                 if (!call) {
 961                         rcu_read_unlock();
 962                         goto reject_packet;
 963                 }
 964                 rxrpc_send_ping(call, skb, skew);
 965         }
 966
 967         rxrpc_input_call_packet(call, skb, skew);
 968         goto discard_unlock;
 969
 970 discard_unlock:
 971         rcu_read_unlock();
 972 discard:
 973         rxrpc_free_skb(skb, rxrpc_skb_rx_freed);
 974 out:
 975         trace_rxrpc_rx_done(0, 0);
 976         return;
 977
 978 out_unlock:
 979         rcu_read_unlock();
 980         goto out;
 981
 982 wrong_security:
 983         rcu_read_unlock();
 984         trace_rxrpc_abort("SEC", sp->hdr.cid, sp->hdr.callNumber, sp->hdr.seq,
 985                           RXKADINCONSISTENCY, EBADMSG);
 986         skb->priority = RXKADINCONSISTENCY;
 987         goto post_abort;
 988
 989 bad_message_unlock:
 990         rcu_read_unlock();
 991 bad_message:
 992         trace_rxrpc_abort("BAD", sp->hdr.cid, sp->hdr.callNumber, sp->hdr.seq,
 993                           RX_PROTOCOL_ERROR, EBADMSG);
 994         skb->priority = RX_PROTOCOL_ERROR;
 995 post_abort:
 996         skb->mark = RXRPC_SKB_MARK_LOCAL_ABORT;
 997 reject_packet:
 998         trace_rxrpc_rx_done(skb->mark, skb->priority);
 999         rxrpc_reject_packet(local, skb);
1000         _leave(" [badmsg]");
1001 }