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 (call->ackr_reason) {
 153                 spin_lock_bh(&call->lock);
 154                 call->ackr_reason = 0;
 155                 call->resend_at = call->expire_at;
 156                 call->ack_at = call->expire_at;
 157                 spin_unlock_bh(&call->lock);
 158                 rxrpc_set_timer(call, rxrpc_timer_init_for_reply);
 159         }
 160
 161         if (!test_bit(RXRPC_CALL_TX_LAST, &call->flags))
 162                 rxrpc_rotate_tx_window(call, top);
 163         if (!test_bit(RXRPC_CALL_TX_LAST, &call->flags)) {
 164                 rxrpc_proto_abort("TXL", call, top);
 165                 return false;
 166         }
 167         if (!rxrpc_end_tx_phase(call, true, "ETD"))
 168                 return false;
 169         call->tx_phase = false;
 170         return true;
 171 }
 172
 173 /*
 174  * Scan a jumbo packet to validate its structure and to work out how many
 175  * subpackets it contains.
 176  *
 177  * A jumbo packet is a collection of consecutive packets glued together with
 178  * little headers between that indicate how to change the initial header for
 179  * each subpacket.
 180  *
 181  * RXRPC_JUMBO_PACKET must be set on all but the last subpacket - and all but
 182  * the last are RXRPC_JUMBO_DATALEN in size.  The last subpacket may be of any
 183  * size.
 184  */
 185 static bool rxrpc_validate_jumbo(struct sk_buff *skb)
 186 {
 187         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 188         unsigned int offset = sp->offset;
 189         unsigned int len = skb->len;
 190         int nr_jumbo = 1;
 191         u8 flags = sp->hdr.flags;
 192
 193         do {
 194                 nr_jumbo++;
 195                 if (len - offset < RXRPC_JUMBO_SUBPKTLEN)
 196                         goto protocol_error;
 197                 if (flags & RXRPC_LAST_PACKET)
 198                         goto protocol_error;
 199                 offset += RXRPC_JUMBO_DATALEN;
 200                 if (skb_copy_bits(skb, offset, &flags, 1) < 0)
 201                         goto protocol_error;
 202                 offset += sizeof(struct rxrpc_jumbo_header);
 203         } while (flags & RXRPC_JUMBO_PACKET);
 204
 205         sp->nr_jumbo = nr_jumbo;
 206         return true;
 207
 208 protocol_error:
 209         return false;
 210 }
 211
 212 /*
 213  * Handle reception of a duplicate packet.
 214  *
 215  * We have to take care to avoid an attack here whereby we're given a series of
 216  * jumbograms, each with a sequence number one before the preceding one and
 217  * filled up to maximum UDP size.  If they never send us the first packet in
 218  * the sequence, they can cause us to have to hold on to around 2MiB of kernel
 219  * space until the call times out.
 220  *
 221  * We limit the space usage by only accepting three duplicate jumbo packets per
 222  * call.  After that, we tell the other side we're no longer accepting jumbos
 223  * (that information is encoded in the ACK packet).
 224  */
 225 static void rxrpc_input_dup_data(struct rxrpc_call *call, rxrpc_seq_t seq,
 226                                  u8 annotation, bool *_jumbo_bad)
 227 {
 228         /* Discard normal packets that are duplicates. */
 229         if (annotation == 0)
 230                 return;
 231
 232         /* Skip jumbo subpackets that are duplicates.  When we've had three or
 233          * more partially duplicate jumbo packets, we refuse to take any more
 234          * jumbos for this call.
 235          */
 236         if (!*_jumbo_bad) {
 237                 call->nr_jumbo_bad++;
 238                 *_jumbo_bad = true;
 239         }
 240 }
 241
 242 /*
 243  * Process a DATA packet, adding the packet to the Rx ring.
 244  */
 245 static void rxrpc_input_data(struct rxrpc_call *call, struct sk_buff *skb,
 246                              u16 skew)
 247 {
 248         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 249         unsigned int offset = sp->offset;
 250         unsigned int ix;
 251         rxrpc_serial_t serial = sp->hdr.serial, ack_serial = 0;
 252         rxrpc_seq_t seq = sp->hdr.seq, hard_ack;
 253         bool immediate_ack = false, jumbo_bad = false, queued;
 254         u16 len;
 255         u8 ack = 0, flags, annotation = 0;
 256
 257         _enter("{%u,%u},{%u,%u}",
 258                call->rx_hard_ack, call->rx_top, skb->len, seq);
 259
 260         _proto("Rx DATA %%%u { #%u f=%02x }",
 261                sp->hdr.serial, seq, sp->hdr.flags);
 262
 263         if (call->state >= RXRPC_CALL_COMPLETE)
 264                 return;
 265
 266         /* Received data implicitly ACKs all of the request packets we sent
 267          * when we're acting as a client.
 268          */
 269         if ((call->state == RXRPC_CALL_CLIENT_SEND_REQUEST ||
 270              call->state == RXRPC_CALL_CLIENT_AWAIT_REPLY) &&
 271             !rxrpc_receiving_reply(call))
 272                 return;
 273
 274         call->ackr_prev_seq = seq;
 275
 276         hard_ack = READ_ONCE(call->rx_hard_ack);
 277         if (after(seq, hard_ack + call->rx_winsize)) {
 278                 ack = RXRPC_ACK_EXCEEDS_WINDOW;
 279                 ack_serial = serial;
 280                 goto ack;
 281         }
 282
 283         flags = sp->hdr.flags;
 284         if (flags & RXRPC_JUMBO_PACKET) {
 285                 if (call->nr_jumbo_bad > 3) {
 286                         ack = RXRPC_ACK_NOSPACE;
 287                         ack_serial = serial;
 288                         goto ack;
 289                 }
 290                 annotation = 1;
 291         }
 292
 293 next_subpacket:
 294         queued = false;
 295         ix = seq & RXRPC_RXTX_BUFF_MASK;
 296         len = skb->len;
 297         if (flags & RXRPC_JUMBO_PACKET)
 298                 len = RXRPC_JUMBO_DATALEN;
 299
 300         if (flags & RXRPC_LAST_PACKET) {
 301                 if (test_bit(RXRPC_CALL_RX_LAST, &call->flags) &&
 302                     seq != call->rx_top)
 303                         return rxrpc_proto_abort("LSN", call, seq);
 304         } else {
 305                 if (test_bit(RXRPC_CALL_RX_LAST, &call->flags) &&
 306                     after_eq(seq, call->rx_top))
 307                         return rxrpc_proto_abort("LSA", call, seq);
 308         }
 309
 310         if (before_eq(seq, hard_ack)) {
 311                 ack = RXRPC_ACK_DUPLICATE;
 312                 ack_serial = serial;
 313                 goto skip;
 314         }
 315
 316         if (flags & RXRPC_REQUEST_ACK && !ack) {
 317                 ack = RXRPC_ACK_REQUESTED;
 318                 ack_serial = serial;
 319         }
 320
 321         if (call->rxtx_buffer[ix]) {
 322                 rxrpc_input_dup_data(call, seq, annotation, &jumbo_bad);
 323                 if (ack != RXRPC_ACK_DUPLICATE) {
 324                         ack = RXRPC_ACK_DUPLICATE;
 325                         ack_serial = serial;
 326                 }
 327                 immediate_ack = true;
 328                 goto skip;
 329         }
 330
 331         /* Queue the packet.  We use a couple of memory barriers here as need
 332          * to make sure that rx_top is perceived to be set after the buffer
 333          * pointer and that the buffer pointer is set after the annotation and
 334          * the skb data.
 335          *
 336          * Barriers against rxrpc_recvmsg_data() and rxrpc_rotate_rx_window()
 337          * and also rxrpc_fill_out_ack().
 338          */
 339         rxrpc_get_skb(skb, rxrpc_skb_rx_got);
 340         call->rxtx_annotations[ix] = annotation;
 341         smp_wmb();
 342         call->rxtx_buffer[ix] = skb;
 343         if (after(seq, call->rx_top)) {
 344                 smp_store_release(&call->rx_top, seq);
 345         } else if (before(seq, call->rx_top)) {
 346                 /* Send an immediate ACK if we fill in a hole */
 347                 if (!ack) {
 348                         ack = RXRPC_ACK_DELAY;
 349                         ack_serial = serial;
 350                 }
 351                 immediate_ack = true;
 352         }
 353         if (flags & RXRPC_LAST_PACKET) {
 354                 set_bit(RXRPC_CALL_RX_LAST, &call->flags);
 355                 trace_rxrpc_receive(call, rxrpc_receive_queue_last, serial, seq);
 356         } else {
 357                 trace_rxrpc_receive(call, rxrpc_receive_queue, serial, seq);
 358         }
 359         queued = true;
 360
 361         if (after_eq(seq, call->rx_expect_next)) {
 362                 if (after(seq, call->rx_expect_next)) {
 363                         _net("OOS %u > %u", seq, call->rx_expect_next);
 364                         ack = RXRPC_ACK_OUT_OF_SEQUENCE;
 365                         ack_serial = serial;
 366                 }
 367                 call->rx_expect_next = seq + 1;
 368         }
 369
 370 skip:
 371         offset += len;
 372         if (flags & RXRPC_JUMBO_PACKET) {
 373                 if (skb_copy_bits(skb, offset, &flags, 1) < 0)
 374                         return rxrpc_proto_abort("XJF", call, seq);
 375                 offset += sizeof(struct rxrpc_jumbo_header);
 376                 seq++;
 377                 serial++;
 378                 annotation++;
 379                 if (flags & RXRPC_JUMBO_PACKET)
 380                         annotation |= RXRPC_RX_ANNO_JLAST;
 381                 if (after(seq, hard_ack + call->rx_winsize)) {
 382                         ack = RXRPC_ACK_EXCEEDS_WINDOW;
 383                         ack_serial = serial;
 384                         if (!jumbo_bad) {
 385                                 call->nr_jumbo_bad++;
 386                                 jumbo_bad = true;
 387                         }
 388                         goto ack;
 389                 }
 390
 391                 _proto("Rx DATA Jumbo %%%u", serial);
 392                 goto next_subpacket;
 393         }
 394
 395         if (queued && flags & RXRPC_LAST_PACKET && !ack) {
 396                 ack = RXRPC_ACK_DELAY;
 397                 ack_serial = serial;
 398         }
 399
 400 ack:
 401         if (ack)
 402                 rxrpc_propose_ACK(call, ack, skew, ack_serial,
 403                                   immediate_ack, true,
 404                                   rxrpc_propose_ack_input_data);
 405
 406         if (sp->hdr.seq == READ_ONCE(call->rx_hard_ack) + 1)
 407                 rxrpc_notify_socket(call);
 408         _leave(" [queued]");
 409 }
 410
 411 /*
 412  * Process a requested ACK.
 413  */
 414 static void rxrpc_input_requested_ack(struct rxrpc_call *call,
 415                                       ktime_t resp_time,
 416                                       rxrpc_serial_t orig_serial,
 417                                       rxrpc_serial_t ack_serial)
 418 {
 419         struct rxrpc_skb_priv *sp;
 420         struct sk_buff *skb;
 421         ktime_t sent_at;
 422         int ix;
 423
 424         for (ix = 0; ix < RXRPC_RXTX_BUFF_SIZE; ix++) {
 425                 skb = call->rxtx_buffer[ix];
 426                 if (!skb)
 427                         continue;
 428
 429                 sp = rxrpc_skb(skb);
 430                 if (sp->hdr.serial != orig_serial)
 431                         continue;
 432                 smp_rmb();
 433                 sent_at = skb->tstamp;
 434                 goto found;
 435         }
 436         return;
 437
 438 found:
 439         rxrpc_peer_add_rtt(call, rxrpc_rtt_rx_requested_ack,
 440                            orig_serial, ack_serial, sent_at, resp_time);
 441 }
 442
 443 /*
 444  * Process a ping response.
 445  */
 446 static void rxrpc_input_ping_response(struct rxrpc_call *call,
 447                                       ktime_t resp_time,
 448                                       rxrpc_serial_t orig_serial,
 449                                       rxrpc_serial_t ack_serial)
 450 {
 451         rxrpc_serial_t ping_serial;
 452         ktime_t ping_time;
 453
 454         ping_time = call->ackr_ping_time;
 455         smp_rmb();
 456         ping_serial = call->ackr_ping;
 457
 458         if (!test_bit(RXRPC_CALL_PINGING, &call->flags) ||
 459             before(orig_serial, ping_serial))
 460                 return;
 461         clear_bit(RXRPC_CALL_PINGING, &call->flags);
 462         if (after(orig_serial, ping_serial))
 463                 return;
 464
 465         rxrpc_peer_add_rtt(call, rxrpc_rtt_rx_ping_response,
 466                            orig_serial, ack_serial, ping_time, resp_time);
 467 }
 468
 469 /*
 470  * Process the extra information that may be appended to an ACK packet
 471  */
 472 static void rxrpc_input_ackinfo(struct rxrpc_call *call, struct sk_buff *skb,
 473                                 struct rxrpc_ackinfo *ackinfo)
 474 {
 475         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 476         struct rxrpc_peer *peer;
 477         unsigned int mtu;
 478         u32 rwind = ntohl(ackinfo->rwind);
 479
 480         _proto("Rx ACK %%%u Info { rx=%u max=%u rwin=%u jm=%u }",
 481                sp->hdr.serial,
 482                ntohl(ackinfo->rxMTU), ntohl(ackinfo->maxMTU),
 483                rwind, ntohl(ackinfo->jumbo_max));
 484
 485         if (rwind > RXRPC_RXTX_BUFF_SIZE - 1)
 486                 rwind = RXRPC_RXTX_BUFF_SIZE - 1;
 487         call->tx_winsize = rwind;
 488
 489         mtu = min(ntohl(ackinfo->rxMTU), ntohl(ackinfo->maxMTU));
 490
 491         peer = call->peer;
 492         if (mtu < peer->maxdata) {
 493                 spin_lock_bh(&peer->lock);
 494                 peer->maxdata = mtu;
 495                 peer->mtu = mtu + peer->hdrsize;
 496                 spin_unlock_bh(&peer->lock);
 497                 _net("Net MTU %u (maxdata %u)", peer->mtu, peer->maxdata);
 498         }
 499 }
 500
 501 /*
 502  * Process individual soft ACKs.
 503  *
 504  * Each ACK in the array corresponds to one packet and can be either an ACK or
 505  * a NAK.  If we get find an explicitly NAK'd packet we resend immediately;
 506  * packets that lie beyond the end of the ACK list are scheduled for resend by
 507  * the timer on the basis that the peer might just not have processed them at
 508  * the time the ACK was sent.
 509  */
 510 static void rxrpc_input_soft_acks(struct rxrpc_call *call, u8 *acks,
 511                                   rxrpc_seq_t seq, int nr_acks)
 512 {
 513         bool resend = false;
 514         int ix;
 515         u8 annotation, anno_type;
 516
 517         for (; nr_acks > 0; nr_acks--, seq++) {
 518                 ix = seq & RXRPC_RXTX_BUFF_MASK;
 519                 annotation = call->rxtx_annotations[ix];
 520                 anno_type = annotation & RXRPC_TX_ANNO_MASK;
 521                 annotation &= ~RXRPC_TX_ANNO_MASK;
 522                 switch (*acks++) {
 523                 case RXRPC_ACK_TYPE_ACK:
 524                         if (anno_type == RXRPC_TX_ANNO_ACK)
 525                                 continue;
 526                         call->rxtx_annotations[ix] =
 527                                 RXRPC_TX_ANNO_ACK | annotation;
 528                         break;
 529                 case RXRPC_ACK_TYPE_NACK:
 530                         if (anno_type == RXRPC_TX_ANNO_NAK)
 531                                 continue;
 532                         if (anno_type == RXRPC_TX_ANNO_RETRANS)
 533                                 continue;
 534                         call->rxtx_annotations[ix] =
 535                                 RXRPC_TX_ANNO_NAK | annotation;
 536                         resend = true;
 537                         break;
 538                 default:
 539                         return rxrpc_proto_abort("SFT", call, 0);
 540                 }
 541         }
 542
 543         if (resend &&
 544             !test_and_set_bit(RXRPC_CALL_EV_RESEND, &call->events))
 545                 rxrpc_queue_call(call);
 546 }
 547
 548 /*
 549  * Process an ACK packet.
 550  *
 551  * ack.firstPacket is the sequence number of the first soft-ACK'd/NAK'd packet
 552  * in the ACK array.  Anything before that is hard-ACK'd and may be discarded.
 553  *
 554  * A hard-ACK means that a packet has been processed and may be discarded; a
 555  * soft-ACK means that the packet may be discarded and retransmission
 556  * requested.  A phase is complete when all packets are hard-ACK'd.
 557  */
 558 static void rxrpc_input_ack(struct rxrpc_call *call, struct sk_buff *skb,
 559                             u16 skew)
 560 {
 561         u8 ack_reason;
 562         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 563         union {
 564                 struct rxrpc_ackpacket ack;
 565                 struct rxrpc_ackinfo info;
 566                 u8 acks[RXRPC_MAXACKS];
 567         } buf;
 568         rxrpc_serial_t acked_serial;
 569         rxrpc_seq_t first_soft_ack, hard_ack;
 570         int nr_acks, offset;
 571
 572         _enter("");
 573
 574         if (skb_copy_bits(skb, sp->offset, &buf.ack, sizeof(buf.ack)) < 0) {
 575                 _debug("extraction failure");
 576                 return rxrpc_proto_abort("XAK", call, 0);
 577         }
 578         sp->offset += sizeof(buf.ack);
 579
 580         acked_serial = ntohl(buf.ack.serial);
 581         first_soft_ack = ntohl(buf.ack.firstPacket);
 582         hard_ack = first_soft_ack - 1;
 583         nr_acks = buf.ack.nAcks;
 584         ack_reason = (buf.ack.reason < RXRPC_ACK__INVALID ?
 585                       buf.ack.reason : RXRPC_ACK__INVALID);
 586
 587         trace_rxrpc_rx_ack(call, first_soft_ack, ack_reason, nr_acks);
 588
 589         _proto("Rx ACK %%%u { m=%hu f=#%u p=#%u s=%%%u r=%s n=%u }",
 590                sp->hdr.serial,
 591                ntohs(buf.ack.maxSkew),
 592                first_soft_ack,
 593                ntohl(buf.ack.previousPacket),
 594                acked_serial,
 595                rxrpc_ack_names[ack_reason],
 596                buf.ack.nAcks);
 597
 598         if (buf.ack.reason == RXRPC_ACK_PING_RESPONSE)
 599                 rxrpc_input_ping_response(call, skb->tstamp, acked_serial,
 600                                           sp->hdr.serial);
 601         if (buf.ack.reason == RXRPC_ACK_REQUESTED)
 602                 rxrpc_input_requested_ack(call, skb->tstamp, acked_serial,
 603                                           sp->hdr.serial);
 604
 605         if (buf.ack.reason == RXRPC_ACK_PING) {
 606                 _proto("Rx ACK %%%u PING Request", sp->hdr.serial);
 607                 rxrpc_propose_ACK(call, RXRPC_ACK_PING_RESPONSE,
 608                                   skew, sp->hdr.serial, true, true,
 609                                   rxrpc_propose_ack_respond_to_ping);
 610         } else if (sp->hdr.flags & RXRPC_REQUEST_ACK) {
 611                 rxrpc_propose_ACK(call, RXRPC_ACK_REQUESTED,
 612                                   skew, sp->hdr.serial, true, true,
 613                                   rxrpc_propose_ack_respond_to_ack);
 614         }
 615
 616         offset = sp->offset + nr_acks + 3;
 617         if (skb->len >= offset + sizeof(buf.info)) {
 618                 if (skb_copy_bits(skb, offset, &buf.info, sizeof(buf.info)) < 0)
 619                         return rxrpc_proto_abort("XAI", call, 0);
 620                 rxrpc_input_ackinfo(call, skb, &buf.info);
 621         }
 622
 623         if (first_soft_ack == 0)
 624                 return rxrpc_proto_abort("AK0", call, 0);
 625
 626         /* Ignore ACKs unless we are or have just been transmitting. */
 627         switch (call->state) {
 628         case RXRPC_CALL_CLIENT_SEND_REQUEST:
 629         case RXRPC_CALL_CLIENT_AWAIT_REPLY:
 630         case RXRPC_CALL_SERVER_SEND_REPLY:
 631         case RXRPC_CALL_SERVER_AWAIT_ACK:
 632                 break;
 633         default:
 634                 return;
 635         }
 636
 637         /* Discard any out-of-order or duplicate ACKs. */
 638         if (before_eq(sp->hdr.serial, call->acks_latest)) {
 639                 _debug("discard ACK %d <= %d",
 640                        sp->hdr.serial, call->acks_latest);
 641                 return;
 642         }
 643         call->acks_latest = sp->hdr.serial;
 644
 645         if (before(hard_ack, call->tx_hard_ack) ||
 646             after(hard_ack, call->tx_top))
 647                 return rxrpc_proto_abort("AKW", call, 0);
 648         if (nr_acks > call->tx_top - hard_ack)
 649                 return rxrpc_proto_abort("AKN", call, 0);
 650
 651         if (after(hard_ack, call->tx_hard_ack))
 652                 rxrpc_rotate_tx_window(call, hard_ack);
 653
 654         if (nr_acks > 0) {
 655                 if (skb_copy_bits(skb, sp->offset, buf.acks, nr_acks) < 0)
 656                         return rxrpc_proto_abort("XSA", call, 0);
 657                 rxrpc_input_soft_acks(call, buf.acks, first_soft_ack, nr_acks);
 658         }
 659
 660         if (test_bit(RXRPC_CALL_TX_LAST, &call->flags)) {
 661                 rxrpc_end_tx_phase(call, false, "ETA");
 662                 return;
 663         }
 664
 665 }
 666
 667 /*
 668  * Process an ACKALL packet.
 669  */
 670 static void rxrpc_input_ackall(struct rxrpc_call *call, struct sk_buff *skb)
 671 {
 672         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 673
 674         _proto("Rx ACKALL %%%u", sp->hdr.serial);
 675
 676         rxrpc_rotate_tx_window(call, call->tx_top);
 677         if (test_bit(RXRPC_CALL_TX_LAST, &call->flags))
 678                 rxrpc_end_tx_phase(call, false, "ETL");
 679 }
 680
 681 /*
 682  * Process an ABORT packet.
 683  */
 684 static void rxrpc_input_abort(struct rxrpc_call *call, struct sk_buff *skb)
 685 {
 686         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 687         __be32 wtmp;
 688         u32 abort_code = RX_CALL_DEAD;
 689
 690         _enter("");
 691
 692         if (skb->len >= 4 &&
 693             skb_copy_bits(skb, sp->offset, &wtmp, sizeof(wtmp)) >= 0)
 694                 abort_code = ntohl(wtmp);
 695
 696         _proto("Rx ABORT %%%u { %x }", sp->hdr.serial, abort_code);
 697
 698         if (rxrpc_set_call_completion(call, RXRPC_CALL_REMOTELY_ABORTED,
 699                                       abort_code, ECONNABORTED))
 700                 rxrpc_notify_socket(call);
 701 }
 702
 703 /*
 704  * Process an incoming call packet.
 705  */
 706 static void rxrpc_input_call_packet(struct rxrpc_call *call,
 707                                     struct sk_buff *skb, u16 skew)
 708 {
 709         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 710
 711         _enter("%p,%p", call, skb);
 712
 713         switch (sp->hdr.type) {
 714         case RXRPC_PACKET_TYPE_DATA:
 715                 rxrpc_input_data(call, skb, skew);
 716                 break;
 717
 718         case RXRPC_PACKET_TYPE_ACK:
 719                 rxrpc_input_ack(call, skb, skew);
 720                 break;
 721
 722         case RXRPC_PACKET_TYPE_BUSY:
 723                 _proto("Rx BUSY %%%u", sp->hdr.serial);
 724
 725                 /* Just ignore BUSY packets from the server; the retry and
 726                  * lifespan timers will take care of business.  BUSY packets
 727                  * from the client don't make sense.
 728                  */
 729                 break;
 730
 731         case RXRPC_PACKET_TYPE_ABORT:
 732                 rxrpc_input_abort(call, skb);
 733                 break;
 734
 735         case RXRPC_PACKET_TYPE_ACKALL:
 736                 rxrpc_input_ackall(call, skb);
 737                 break;
 738
 739         default:
 740                 _proto("Rx %s %%%u", rxrpc_pkts[sp->hdr.type], sp->hdr.serial);
 741                 break;
 742         }
 743
 744         _leave("");
 745 }
 746
 747 /*
 748  * post connection-level events to the connection
 749  * - this includes challenges, responses, some aborts and call terminal packet
 750  *   retransmission.
 751  */
 752 static void rxrpc_post_packet_to_conn(struct rxrpc_connection *conn,
 753                                       struct sk_buff *skb)
 754 {
 755         _enter("%p,%p", conn, skb);
 756
 757         skb_queue_tail(&conn->rx_queue, skb);
 758         rxrpc_queue_conn(conn);
 759 }
 760
 761 /*
 762  * post endpoint-level events to the local endpoint
 763  * - this includes debug and version messages
 764  */
 765 static void rxrpc_post_packet_to_local(struct rxrpc_local *local,
 766                                        struct sk_buff *skb)
 767 {
 768         _enter("%p,%p", local, skb);
 769
 770         skb_queue_tail(&local->event_queue, skb);
 771         rxrpc_queue_local(local);
 772 }
 773
 774 /*
 775  * put a packet up for transport-level abort
 776  */
 777 static void rxrpc_reject_packet(struct rxrpc_local *local, struct sk_buff *skb)
 778 {
 779         CHECK_SLAB_OKAY(&local->usage);
 780
 781         skb_queue_tail(&local->reject_queue, skb);
 782         rxrpc_queue_local(local);
 783 }
 784
 785 /*
 786  * Extract the wire header from a packet and translate the byte order.
 787  */
 788 static noinline
 789 int rxrpc_extract_header(struct rxrpc_skb_priv *sp, struct sk_buff *skb)
 790 {
 791         struct rxrpc_wire_header whdr;
 792
 793         /* dig out the RxRPC connection details */
 794         if (skb_copy_bits(skb, 0, &whdr, sizeof(whdr)) < 0)
 795                 return -EBADMSG;
 796
 797         memset(sp, 0, sizeof(*sp));
 798         sp->hdr.epoch           = ntohl(whdr.epoch);
 799         sp->hdr.cid             = ntohl(whdr.cid);
 800         sp->hdr.callNumber      = ntohl(whdr.callNumber);
 801         sp->hdr.seq             = ntohl(whdr.seq);
 802         sp->hdr.serial          = ntohl(whdr.serial);
 803         sp->hdr.flags           = whdr.flags;
 804         sp->hdr.type            = whdr.type;
 805         sp->hdr.userStatus      = whdr.userStatus;
 806         sp->hdr.securityIndex   = whdr.securityIndex;
 807         sp->hdr._rsvd           = ntohs(whdr._rsvd);
 808         sp->hdr.serviceId       = ntohs(whdr.serviceId);
 809         sp->offset = sizeof(whdr);
 810         return 0;
 811 }
 812
 813 /*
 814  * handle data received on the local endpoint
 815  * - may be called in interrupt context
 816  *
 817  * The socket is locked by the caller and this prevents the socket from being
 818  * shut down and the local endpoint from going away, thus sk_user_data will not
 819  * be cleared until this function returns.
 820  */
 821 void rxrpc_data_ready(struct sock *udp_sk)
 822 {
 823         struct rxrpc_connection *conn;
 824         struct rxrpc_channel *chan;
 825         struct rxrpc_call *call;
 826         struct rxrpc_skb_priv *sp;
 827         struct rxrpc_local *local = udp_sk->sk_user_data;
 828         struct sk_buff *skb;
 829         unsigned int channel;
 830         int ret, skew;
 831
 832         _enter("%p", udp_sk);
 833
 834         ASSERT(!irqs_disabled());
 835
 836         skb = skb_recv_datagram(udp_sk, 0, 1, &ret);
 837         if (!skb) {
 838                 if (ret == -EAGAIN)
 839                         return;
 840                 _debug("UDP socket error %d", ret);
 841                 return;
 842         }
 843
 844         rxrpc_new_skb(skb, rxrpc_skb_rx_received);
 845
 846         _net("recv skb %p", skb);
 847
 848         /* we'll probably need to checksum it (didn't call sock_recvmsg) */
 849         if (skb_checksum_complete(skb)) {
 850                 rxrpc_free_skb(skb, rxrpc_skb_rx_freed);
 851                 __UDP_INC_STATS(&init_net, UDP_MIB_INERRORS, 0);
 852                 _leave(" [CSUM failed]");
 853                 return;
 854         }
 855
 856         __UDP_INC_STATS(&init_net, UDP_MIB_INDATAGRAMS, 0);
 857
 858         /* The socket buffer we have is owned by UDP, with UDP's data all over
 859          * it, but we really want our own data there.
 860          */
 861         skb_orphan(skb);
 862         sp = rxrpc_skb(skb);
 863
 864         /* dig out the RxRPC connection details */
 865         if (rxrpc_extract_header(sp, skb) < 0)
 866                 goto bad_message;
 867
 868         if (IS_ENABLED(CONFIG_AF_RXRPC_INJECT_LOSS)) {
 869                 static int lose;
 870                 if ((lose++ & 7) == 7) {
 871                         trace_rxrpc_rx_lose(sp);
 872                         rxrpc_lose_skb(skb, rxrpc_skb_rx_lost);
 873                         return;
 874                 }
 875         }
 876
 877         trace_rxrpc_rx_packet(sp);
 878
 879         _net("Rx RxRPC %s ep=%x call=%x:%x",
 880              sp->hdr.flags & RXRPC_CLIENT_INITIATED ? "ToServer" : "ToClient",
 881              sp->hdr.epoch, sp->hdr.cid, sp->hdr.callNumber);
 882
 883         if (sp->hdr.type >= RXRPC_N_PACKET_TYPES ||
 884             !((RXRPC_SUPPORTED_PACKET_TYPES >> sp->hdr.type) & 1)) {
 885                 _proto("Rx Bad Packet Type %u", sp->hdr.type);
 886                 goto bad_message;
 887         }
 888
 889         switch (sp->hdr.type) {
 890         case RXRPC_PACKET_TYPE_VERSION:
 891                 rxrpc_post_packet_to_local(local, skb);
 892                 goto out;
 893
 894         case RXRPC_PACKET_TYPE_BUSY:
 895                 if (sp->hdr.flags & RXRPC_CLIENT_INITIATED)
 896                         goto discard;
 897
 898         case RXRPC_PACKET_TYPE_DATA:
 899                 if (sp->hdr.callNumber == 0)
 900                         goto bad_message;
 901                 if (sp->hdr.flags & RXRPC_JUMBO_PACKET &&
 902                     !rxrpc_validate_jumbo(skb))
 903                         goto bad_message;
 904                 break;
 905         }
 906
 907         rcu_read_lock();
 908
 909         conn = rxrpc_find_connection_rcu(local, skb);
 910         if (conn) {
 911                 if (sp->hdr.securityIndex != conn->security_ix)
 912                         goto wrong_security;
 913
 914                 if (sp->hdr.callNumber == 0) {
 915                         /* Connection-level packet */
 916                         _debug("CONN %p {%d}", conn, conn->debug_id);
 917                         rxrpc_post_packet_to_conn(conn, skb);
 918                         goto out_unlock;
 919                 }
 920
 921                 /* Note the serial number skew here */
 922                 skew = (int)sp->hdr.serial - (int)conn->hi_serial;
 923                 if (skew >= 0) {
 924                         if (skew > 0)
 925                                 conn->hi_serial = sp->hdr.serial;
 926                 } else {
 927                         skew = -skew;
 928                         skew = min(skew, 65535);
 929                 }
 930
 931                 /* Call-bound packets are routed by connection channel. */
 932                 channel = sp->hdr.cid & RXRPC_CHANNELMASK;
 933                 chan = &conn->channels[channel];
 934
 935                 /* Ignore really old calls */
 936                 if (sp->hdr.callNumber < chan->last_call)
 937                         goto discard_unlock;
 938
 939                 if (sp->hdr.callNumber == chan->last_call) {
 940                         /* For the previous service call, if completed successfully, we
 941                          * discard all further packets.
 942                          */
 943                         if (rxrpc_conn_is_service(conn) &&
 944                             (chan->last_type == RXRPC_PACKET_TYPE_ACK ||
 945                              sp->hdr.type == RXRPC_PACKET_TYPE_ABORT))
 946                                 goto discard_unlock;
 947
 948                         /* But otherwise we need to retransmit the final packet from
 949                          * data cached in the connection record.
 950                          */
 951                         rxrpc_post_packet_to_conn(conn, skb);
 952                         goto out_unlock;
 953                 }
 954
 955                 call = rcu_dereference(chan->call);
 956         } else {
 957                 skew = 0;
 958                 call = NULL;
 959         }
 960
 961         if (!call || atomic_read(&call->usage) == 0) {
 962                 if (!(sp->hdr.type & RXRPC_CLIENT_INITIATED) ||
 963                     sp->hdr.callNumber == 0 ||
 964                     sp->hdr.type != RXRPC_PACKET_TYPE_DATA)
 965                         goto bad_message_unlock;
 966                 if (sp->hdr.seq != 1)
 967                         goto discard_unlock;
 968                 call = rxrpc_new_incoming_call(local, conn, skb);
 969                 if (!call) {
 970                         rcu_read_unlock();
 971                         goto reject_packet;
 972                 }
 973                 rxrpc_send_ping(call, skb, skew);
 974         }
 975
 976         rxrpc_input_call_packet(call, skb, skew);
 977         goto discard_unlock;
 978
 979 discard_unlock:
 980         rcu_read_unlock();
 981 discard:
 982         rxrpc_free_skb(skb, rxrpc_skb_rx_freed);
 983 out:
 984         trace_rxrpc_rx_done(0, 0);
 985         return;
 986
 987 out_unlock:
 988         rcu_read_unlock();
 989         goto out;
 990
 991 wrong_security:
 992         rcu_read_unlock();
 993         trace_rxrpc_abort("SEC", sp->hdr.cid, sp->hdr.callNumber, sp->hdr.seq,
 994                           RXKADINCONSISTENCY, EBADMSG);
 995         skb->priority = RXKADINCONSISTENCY;
 996         goto post_abort;
 997
 998 bad_message_unlock:
 999         rcu_read_unlock();
1000 bad_message:
1001         trace_rxrpc_abort("BAD", sp->hdr.cid, sp->hdr.callNumber, sp->hdr.seq,
1002                           RX_PROTOCOL_ERROR, EBADMSG);
1003         skb->priority = RX_PROTOCOL_ERROR;
1004 post_abort:
1005         skb->mark = RXRPC_SKB_MARK_LOCAL_ABORT;
1006 reject_packet:
1007         trace_rxrpc_rx_done(skb->mark, skb->priority);
1008         rxrpc_reject_packet(local, skb);
1009         _leave(" [badmsg]");
1010 }