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v5.4
   1// SPDX-License-Identifier: GPL-2.0-or-later
   2/* RxRPC packet reception
   3 *
   4 * Copyright (C) 2007, 2016 Red Hat, Inc. All Rights Reserved.
   5 * Written by David Howells (dhowells@redhat.com)
   6 */
   7
   8#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
   9
  10#include <linux/module.h>
  11#include <linux/net.h>
  12#include <linux/skbuff.h>
  13#include <linux/errqueue.h>
  14#include <linux/udp.h>
  15#include <linux/in.h>
  16#include <linux/in6.h>
  17#include <linux/icmp.h>
  18#include <linux/gfp.h>
  19#include <net/sock.h>
  20#include <net/af_rxrpc.h>
  21#include <net/ip.h>
  22#include <net/udp.h>
  23#include <net/net_namespace.h>
  24#include "ar-internal.h"
  25
  26static void rxrpc_proto_abort(const char *why,
  27			      struct rxrpc_call *call, rxrpc_seq_t seq)
  28{
  29	if (rxrpc_abort_call(why, call, seq, RX_PROTOCOL_ERROR, -EBADMSG)) {
  30		set_bit(RXRPC_CALL_EV_ABORT, &call->events);
  31		rxrpc_queue_call(call);
  32	}
  33}
  34
  35/*
  36 * Do TCP-style congestion management [RFC 5681].
  37 */
  38static void rxrpc_congestion_management(struct rxrpc_call *call,
  39					struct sk_buff *skb,
  40					struct rxrpc_ack_summary *summary,
  41					rxrpc_serial_t acked_serial)
  42{
  43	enum rxrpc_congest_change change = rxrpc_cong_no_change;
  44	unsigned int cumulative_acks = call->cong_cumul_acks;
  45	unsigned int cwnd = call->cong_cwnd;
  46	bool resend = false;
  47
  48	summary->flight_size =
  49		(call->tx_top - call->tx_hard_ack) - summary->nr_acks;
  50
  51	if (test_and_clear_bit(RXRPC_CALL_RETRANS_TIMEOUT, &call->flags)) {
  52		summary->retrans_timeo = true;
  53		call->cong_ssthresh = max_t(unsigned int,
  54					    summary->flight_size / 2, 2);
  55		cwnd = 1;
  56		if (cwnd >= call->cong_ssthresh &&
  57		    call->cong_mode == RXRPC_CALL_SLOW_START) {
  58			call->cong_mode = RXRPC_CALL_CONGEST_AVOIDANCE;
  59			call->cong_tstamp = skb->tstamp;
  60			cumulative_acks = 0;
  61		}
  62	}
  63
  64	cumulative_acks += summary->nr_new_acks;
  65	cumulative_acks += summary->nr_rot_new_acks;
  66	if (cumulative_acks > 255)
  67		cumulative_acks = 255;
  68
  69	summary->mode = call->cong_mode;
  70	summary->cwnd = call->cong_cwnd;
  71	summary->ssthresh = call->cong_ssthresh;
  72	summary->cumulative_acks = cumulative_acks;
  73	summary->dup_acks = call->cong_dup_acks;
  74
  75	switch (call->cong_mode) {
  76	case RXRPC_CALL_SLOW_START:
  77		if (summary->nr_nacks > 0)
  78			goto packet_loss_detected;
  79		if (summary->cumulative_acks > 0)
  80			cwnd += 1;
  81		if (cwnd >= call->cong_ssthresh) {
  82			call->cong_mode = RXRPC_CALL_CONGEST_AVOIDANCE;
  83			call->cong_tstamp = skb->tstamp;
  84		}
  85		goto out;
  86
  87	case RXRPC_CALL_CONGEST_AVOIDANCE:
  88		if (summary->nr_nacks > 0)
  89			goto packet_loss_detected;
  90
  91		/* We analyse the number of packets that get ACK'd per RTT
  92		 * period and increase the window if we managed to fill it.
  93		 */
  94		if (call->peer->rtt_usage == 0)
  95			goto out;
  96		if (ktime_before(skb->tstamp,
  97				 ktime_add_ns(call->cong_tstamp,
  98					      call->peer->rtt)))
  99			goto out_no_clear_ca;
 100		change = rxrpc_cong_rtt_window_end;
 101		call->cong_tstamp = skb->tstamp;
 102		if (cumulative_acks >= cwnd)
 103			cwnd++;
 104		goto out;
 105
 106	case RXRPC_CALL_PACKET_LOSS:
 107		if (summary->nr_nacks == 0)
 108			goto resume_normality;
 109
 110		if (summary->new_low_nack) {
 111			change = rxrpc_cong_new_low_nack;
 112			call->cong_dup_acks = 1;
 113			if (call->cong_extra > 1)
 114				call->cong_extra = 1;
 115			goto send_extra_data;
 116		}
 117
 118		call->cong_dup_acks++;
 119		if (call->cong_dup_acks < 3)
 120			goto send_extra_data;
 121
 122		change = rxrpc_cong_begin_retransmission;
 123		call->cong_mode = RXRPC_CALL_FAST_RETRANSMIT;
 124		call->cong_ssthresh = max_t(unsigned int,
 125					    summary->flight_size / 2, 2);
 126		cwnd = call->cong_ssthresh + 3;
 127		call->cong_extra = 0;
 128		call->cong_dup_acks = 0;
 129		resend = true;
 130		goto out;
 131
 132	case RXRPC_CALL_FAST_RETRANSMIT:
 133		if (!summary->new_low_nack) {
 134			if (summary->nr_new_acks == 0)
 135				cwnd += 1;
 136			call->cong_dup_acks++;
 137			if (call->cong_dup_acks == 2) {
 138				change = rxrpc_cong_retransmit_again;
 139				call->cong_dup_acks = 0;
 140				resend = true;
 141			}
 142		} else {
 143			change = rxrpc_cong_progress;
 144			cwnd = call->cong_ssthresh;
 145			if (summary->nr_nacks == 0)
 146				goto resume_normality;
 147		}
 148		goto out;
 149
 150	default:
 151		BUG();
 152		goto out;
 153	}
 154
 155resume_normality:
 156	change = rxrpc_cong_cleared_nacks;
 157	call->cong_dup_acks = 0;
 158	call->cong_extra = 0;
 159	call->cong_tstamp = skb->tstamp;
 160	if (cwnd < call->cong_ssthresh)
 161		call->cong_mode = RXRPC_CALL_SLOW_START;
 162	else
 163		call->cong_mode = RXRPC_CALL_CONGEST_AVOIDANCE;
 164out:
 165	cumulative_acks = 0;
 166out_no_clear_ca:
 167	if (cwnd >= RXRPC_RXTX_BUFF_SIZE - 1)
 168		cwnd = RXRPC_RXTX_BUFF_SIZE - 1;
 169	call->cong_cwnd = cwnd;
 170	call->cong_cumul_acks = cumulative_acks;
 
 171	trace_rxrpc_congest(call, summary, acked_serial, change);
 172	if (resend && !test_and_set_bit(RXRPC_CALL_EV_RESEND, &call->events))
 173		rxrpc_queue_call(call);
 174	return;
 175
 176packet_loss_detected:
 177	change = rxrpc_cong_saw_nack;
 178	call->cong_mode = RXRPC_CALL_PACKET_LOSS;
 179	call->cong_dup_acks = 0;
 180	goto send_extra_data;
 181
 182send_extra_data:
 183	/* Send some previously unsent DATA if we have some to advance the ACK
 184	 * state.
 185	 */
 186	if (call->rxtx_annotations[call->tx_top & RXRPC_RXTX_BUFF_MASK] &
 187	    RXRPC_TX_ANNO_LAST ||
 188	    summary->nr_acks != call->tx_top - call->tx_hard_ack) {
 189		call->cong_extra++;
 190		wake_up(&call->waitq);
 191	}
 192	goto out_no_clear_ca;
 193}
 194
 195/*
 196 * Ping the other end to fill our RTT cache and to retrieve the rwind
 197 * and MTU parameters.
 198 */
 199static void rxrpc_send_ping(struct rxrpc_call *call, struct sk_buff *skb)
 200{
 201	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 202	ktime_t now = skb->tstamp;
 
 
 
 
 
 
 
 
 
 
 203
 204	if (call->peer->rtt_usage < 3 ||
 205	    ktime_before(ktime_add_ms(call->peer->rtt_last_req, 1000), now))
 206		rxrpc_propose_ACK(call, RXRPC_ACK_PING, sp->hdr.serial,
 207				  true, true,
 208				  rxrpc_propose_ack_ping_for_params);
 
 
 209}
 210
 211/*
 212 * Apply a hard ACK by advancing the Tx window.
 213 */
 214static bool rxrpc_rotate_tx_window(struct rxrpc_call *call, rxrpc_seq_t to,
 215				   struct rxrpc_ack_summary *summary)
 216{
 217	struct sk_buff *skb, *list = NULL;
 218	bool rot_last = false;
 219	int ix;
 220	u8 annotation;
 221
 222	if (call->acks_lowest_nak == call->tx_hard_ack) {
 223		call->acks_lowest_nak = to;
 224	} else if (before_eq(call->acks_lowest_nak, to)) {
 225		summary->new_low_nack = true;
 226		call->acks_lowest_nak = to;
 227	}
 228
 229	spin_lock(&call->lock);
 230
 231	while (before(call->tx_hard_ack, to)) {
 232		call->tx_hard_ack++;
 233		ix = call->tx_hard_ack & RXRPC_RXTX_BUFF_MASK;
 234		skb = call->rxtx_buffer[ix];
 235		annotation = call->rxtx_annotations[ix];
 236		rxrpc_see_skb(skb, rxrpc_skb_rotated);
 237		call->rxtx_buffer[ix] = NULL;
 238		call->rxtx_annotations[ix] = 0;
 239		skb->next = list;
 240		list = skb;
 241
 242		if (annotation & RXRPC_TX_ANNO_LAST) {
 243			set_bit(RXRPC_CALL_TX_LAST, &call->flags);
 244			rot_last = true;
 245		}
 246		if ((annotation & RXRPC_TX_ANNO_MASK) != RXRPC_TX_ANNO_ACK)
 247			summary->nr_rot_new_acks++;
 248	}
 249
 250	spin_unlock(&call->lock);
 
 251
 252	trace_rxrpc_transmit(call, (rot_last ?
 253				    rxrpc_transmit_rotate_last :
 254				    rxrpc_transmit_rotate));
 255	wake_up(&call->waitq);
 256
 257	while (list) {
 258		skb = list;
 259		list = skb->next;
 260		skb_mark_not_on_list(skb);
 261		rxrpc_free_skb(skb, rxrpc_skb_freed);
 262	}
 263
 
 
 
 
 
 
 264	return rot_last;
 265}
 266
 267/*
 268 * End the transmission phase of a call.
 269 *
 270 * This occurs when we get an ACKALL packet, the first DATA packet of a reply,
 271 * or a final ACK packet.
 272 */
 273static bool rxrpc_end_tx_phase(struct rxrpc_call *call, bool reply_begun,
 274			       const char *abort_why)
 275{
 276	unsigned int state;
 277
 278	ASSERT(test_bit(RXRPC_CALL_TX_LAST, &call->flags));
 279
 280	write_lock(&call->state_lock);
 
 
 
 281
 282	state = call->state;
 283	switch (state) {
 284	case RXRPC_CALL_CLIENT_SEND_REQUEST:
 285	case RXRPC_CALL_CLIENT_AWAIT_REPLY:
 286		if (reply_begun)
 287			call->state = state = RXRPC_CALL_CLIENT_RECV_REPLY;
 288		else
 289			call->state = state = RXRPC_CALL_CLIENT_AWAIT_REPLY;
 
 
 
 
 290		break;
 291
 292	case RXRPC_CALL_SERVER_AWAIT_ACK:
 293		__rxrpc_call_completed(call);
 294		rxrpc_notify_socket(call);
 295		state = call->state;
 296		break;
 297
 298	default:
 299		goto bad_state;
 
 
 300	}
 301
 302	write_unlock(&call->state_lock);
 303	if (state == RXRPC_CALL_CLIENT_AWAIT_REPLY)
 304		trace_rxrpc_transmit(call, rxrpc_transmit_await_reply);
 305	else
 306		trace_rxrpc_transmit(call, rxrpc_transmit_end);
 307	_leave(" = ok");
 308	return true;
 309
 310bad_state:
 311	write_unlock(&call->state_lock);
 312	kdebug("end_tx %s", rxrpc_call_states[call->state]);
 313	rxrpc_proto_abort(abort_why, call, call->tx_top);
 314	return false;
 315}
 316
 317/*
 318 * Begin the reply reception phase of a call.
 319 */
 320static bool rxrpc_receiving_reply(struct rxrpc_call *call)
 321{
 322	struct rxrpc_ack_summary summary = { 0 };
 323	unsigned long now, timo;
 324	rxrpc_seq_t top = READ_ONCE(call->tx_top);
 325
 326	if (call->ackr_reason) {
 327		spin_lock_bh(&call->lock);
 328		call->ackr_reason = 0;
 329		spin_unlock_bh(&call->lock);
 330		now = jiffies;
 331		timo = now + MAX_JIFFY_OFFSET;
 332		WRITE_ONCE(call->resend_at, timo);
 333		WRITE_ONCE(call->ack_at, timo);
 334		trace_rxrpc_timer(call, rxrpc_timer_init_for_reply, now);
 335	}
 336
 337	if (!test_bit(RXRPC_CALL_TX_LAST, &call->flags)) {
 338		if (!rxrpc_rotate_tx_window(call, top, &summary)) {
 339			rxrpc_proto_abort("TXL", call, top);
 340			return false;
 341		}
 342	}
 343	if (!rxrpc_end_tx_phase(call, true, "ETD"))
 344		return false;
 345	call->tx_phase = false;
 346	return true;
 347}
 348
 349/*
 350 * Scan a data packet to validate its structure and to work out how many
 351 * subpackets it contains.
 352 *
 353 * A jumbo packet is a collection of consecutive packets glued together with
 354 * little headers between that indicate how to change the initial header for
 355 * each subpacket.
 356 *
 357 * RXRPC_JUMBO_PACKET must be set on all but the last subpacket - and all but
 358 * the last are RXRPC_JUMBO_DATALEN in size.  The last subpacket may be of any
 359 * size.
 360 */
 361static bool rxrpc_validate_data(struct sk_buff *skb)
 362{
 363	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 364	unsigned int offset = sizeof(struct rxrpc_wire_header);
 365	unsigned int len = skb->len;
 366	u8 flags = sp->hdr.flags;
 367
 368	for (;;) {
 369		if (flags & RXRPC_REQUEST_ACK)
 370			__set_bit(sp->nr_subpackets, sp->rx_req_ack);
 371		sp->nr_subpackets++;
 372
 373		if (!(flags & RXRPC_JUMBO_PACKET))
 374			break;
 375
 376		if (len - offset < RXRPC_JUMBO_SUBPKTLEN)
 377			goto protocol_error;
 378		if (flags & RXRPC_LAST_PACKET)
 379			goto protocol_error;
 380		offset += RXRPC_JUMBO_DATALEN;
 381		if (skb_copy_bits(skb, offset, &flags, 1) < 0)
 382			goto protocol_error;
 383		offset += sizeof(struct rxrpc_jumbo_header);
 384	}
 385
 386	if (flags & RXRPC_LAST_PACKET)
 387		sp->rx_flags |= RXRPC_SKB_INCL_LAST;
 388	return true;
 
 
 389
 390protocol_error:
 391	return false;
 
 
 
 
 
 
 
 
 392}
 393
 394/*
 395 * Handle reception of a duplicate packet.
 396 *
 397 * We have to take care to avoid an attack here whereby we're given a series of
 398 * jumbograms, each with a sequence number one before the preceding one and
 399 * filled up to maximum UDP size.  If they never send us the first packet in
 400 * the sequence, they can cause us to have to hold on to around 2MiB of kernel
 401 * space until the call times out.
 402 *
 403 * We limit the space usage by only accepting three duplicate jumbo packets per
 404 * call.  After that, we tell the other side we're no longer accepting jumbos
 405 * (that information is encoded in the ACK packet).
 406 */
 407static void rxrpc_input_dup_data(struct rxrpc_call *call, rxrpc_seq_t seq,
 408				 bool is_jumbo, bool *_jumbo_bad)
 
 409{
 410	/* Discard normal packets that are duplicates. */
 411	if (is_jumbo)
 412		return;
 413
 414	/* Skip jumbo subpackets that are duplicates.  When we've had three or
 415	 * more partially duplicate jumbo packets, we refuse to take any more
 416	 * jumbos for this call.
 417	 */
 418	if (!*_jumbo_bad) {
 419		call->nr_jumbo_bad++;
 420		*_jumbo_bad = true;
 421	}
 422}
 423
 424/*
 425 * Process a DATA packet, adding the packet to the Rx ring.  The caller's
 426 * packet ref must be passed on or discarded.
 427 */
 428static void rxrpc_input_data(struct rxrpc_call *call, struct sk_buff *skb)
 
 429{
 430	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 431	enum rxrpc_call_state state;
 432	unsigned int j;
 433	rxrpc_serial_t serial = sp->hdr.serial, ack_serial = 0;
 434	rxrpc_seq_t seq0 = sp->hdr.seq, hard_ack;
 435	bool immediate_ack = false, jumbo_bad = false;
 436	u8 ack = 0;
 437
 438	_enter("{%u,%u},{%u,%u}",
 439	       call->rx_hard_ack, call->rx_top, skb->len, seq0);
 440
 441	_proto("Rx DATA %%%u { #%u f=%02x n=%u }",
 442	       sp->hdr.serial, seq0, sp->hdr.flags, sp->nr_subpackets);
 443
 444	state = READ_ONCE(call->state);
 445	if (state >= RXRPC_CALL_COMPLETE) {
 446		rxrpc_free_skb(skb, rxrpc_skb_freed);
 447		return;
 448	}
 449
 450	if (call->state == RXRPC_CALL_SERVER_RECV_REQUEST) {
 451		unsigned long timo = READ_ONCE(call->next_req_timo);
 452		unsigned long now, expect_req_by;
 453
 454		if (timo) {
 455			now = jiffies;
 456			expect_req_by = now + timo;
 457			WRITE_ONCE(call->expect_req_by, expect_req_by);
 458			rxrpc_reduce_call_timer(call, expect_req_by, now,
 459						rxrpc_timer_set_for_idle);
 460		}
 461	}
 462
 463	spin_lock(&call->input_lock);
 
 464
 465	/* Received data implicitly ACKs all of the request packets we sent
 466	 * when we're acting as a client.
 467	 */
 468	if ((state == RXRPC_CALL_CLIENT_SEND_REQUEST ||
 469	     state == RXRPC_CALL_CLIENT_AWAIT_REPLY) &&
 470	    !rxrpc_receiving_reply(call))
 471		goto unlock;
 472
 473	call->ackr_prev_seq = seq0;
 474	hard_ack = READ_ONCE(call->rx_hard_ack);
 475
 476	if (sp->nr_subpackets > 1) {
 477		if (call->nr_jumbo_bad > 3) {
 478			ack = RXRPC_ACK_NOSPACE;
 479			ack_serial = serial;
 480			goto ack;
 481		}
 482	}
 483
 484	for (j = 0; j < sp->nr_subpackets; j++) {
 485		rxrpc_serial_t serial = sp->hdr.serial + j;
 486		rxrpc_seq_t seq = seq0 + j;
 487		unsigned int ix = seq & RXRPC_RXTX_BUFF_MASK;
 488		bool terminal = (j == sp->nr_subpackets - 1);
 489		bool last = terminal && (sp->rx_flags & RXRPC_SKB_INCL_LAST);
 490		u8 flags, annotation = j;
 491
 492		_proto("Rx DATA+%u %%%u { #%x t=%u l=%u }",
 493		     j, serial, seq, terminal, last);
 494
 495		if (last) {
 496			if (test_bit(RXRPC_CALL_RX_LAST, &call->flags) &&
 497			    seq != call->rx_top) {
 498				rxrpc_proto_abort("LSN", call, seq);
 499				goto unlock;
 500			}
 501		} else {
 502			if (test_bit(RXRPC_CALL_RX_LAST, &call->flags) &&
 503			    after_eq(seq, call->rx_top)) {
 504				rxrpc_proto_abort("LSA", call, seq);
 505				goto unlock;
 506			}
 507		}
 508
 509		flags = 0;
 510		if (last)
 511			flags |= RXRPC_LAST_PACKET;
 512		if (!terminal)
 513			flags |= RXRPC_JUMBO_PACKET;
 514		if (test_bit(j, sp->rx_req_ack))
 515			flags |= RXRPC_REQUEST_ACK;
 516		trace_rxrpc_rx_data(call->debug_id, seq, serial, flags, annotation);
 517
 518		if (before_eq(seq, hard_ack)) {
 519			ack = RXRPC_ACK_DUPLICATE;
 520			ack_serial = serial;
 521			continue;
 522		}
 523
 524		if (call->rxtx_buffer[ix]) {
 525			rxrpc_input_dup_data(call, seq, sp->nr_subpackets > 1,
 526					     &jumbo_bad);
 527			if (ack != RXRPC_ACK_DUPLICATE) {
 528				ack = RXRPC_ACK_DUPLICATE;
 529				ack_serial = serial;
 530			}
 531			immediate_ack = true;
 532			continue;
 533		}
 534
 535		if (after(seq, hard_ack + call->rx_winsize)) {
 536			ack = RXRPC_ACK_EXCEEDS_WINDOW;
 537			ack_serial = serial;
 538			if (flags & RXRPC_JUMBO_PACKET) {
 539				if (!jumbo_bad) {
 540					call->nr_jumbo_bad++;
 541					jumbo_bad = true;
 542				}
 543			}
 544
 545			goto ack;
 546		}
 547
 548		if (flags & RXRPC_REQUEST_ACK && !ack) {
 549			ack = RXRPC_ACK_REQUESTED;
 550			ack_serial = serial;
 
 
 
 
 
 
 
 
 
 
 551		}
 552
 553		/* Queue the packet.  We use a couple of memory barriers here as need
 554		 * to make sure that rx_top is perceived to be set after the buffer
 555		 * pointer and that the buffer pointer is set after the annotation and
 556		 * the skb data.
 557		 *
 558		 * Barriers against rxrpc_recvmsg_data() and rxrpc_rotate_rx_window()
 559		 * and also rxrpc_fill_out_ack().
 560		 */
 561		if (!terminal)
 562			rxrpc_get_skb(skb, rxrpc_skb_got);
 563		call->rxtx_annotations[ix] = annotation;
 564		smp_wmb();
 565		call->rxtx_buffer[ix] = skb;
 566		if (after(seq, call->rx_top)) {
 567			smp_store_release(&call->rx_top, seq);
 568		} else if (before(seq, call->rx_top)) {
 569			/* Send an immediate ACK if we fill in a hole */
 570			if (!ack) {
 571				ack = RXRPC_ACK_DELAY;
 572				ack_serial = serial;
 573			}
 574			immediate_ack = true;
 575		}
 576
 577		if (terminal) {
 578			/* From this point on, we're not allowed to touch the
 579			 * packet any longer as its ref now belongs to the Rx
 580			 * ring.
 581			 */
 582			skb = NULL;
 583		}
 584
 585		if (last) {
 586			set_bit(RXRPC_CALL_RX_LAST, &call->flags);
 587			if (!ack) {
 588				ack = RXRPC_ACK_DELAY;
 589				ack_serial = serial;
 590			}
 591			trace_rxrpc_receive(call, rxrpc_receive_queue_last, serial, seq);
 592		} else {
 593			trace_rxrpc_receive(call, rxrpc_receive_queue, serial, seq);
 594		}
 595
 596		if (after_eq(seq, call->rx_expect_next)) {
 597			if (after(seq, call->rx_expect_next)) {
 598				_net("OOS %u > %u", seq, call->rx_expect_next);
 599				ack = RXRPC_ACK_OUT_OF_SEQUENCE;
 600				ack_serial = serial;
 
 
 601			}
 602			call->rx_expect_next = seq + 1;
 603		}
 604	}
 605
 606ack:
 607	if (ack)
 608		rxrpc_propose_ACK(call, ack, ack_serial,
 609				  immediate_ack, true,
 610				  rxrpc_propose_ack_input_data);
 611	else
 612		rxrpc_propose_ACK(call, RXRPC_ACK_DELAY, serial,
 613				  false, true,
 614				  rxrpc_propose_ack_input_data);
 615
 616	if (seq0 == READ_ONCE(call->rx_hard_ack) + 1) {
 617		trace_rxrpc_notify_socket(call->debug_id, serial);
 618		rxrpc_notify_socket(call);
 619	}
 620
 621unlock:
 622	spin_unlock(&call->input_lock);
 623	rxrpc_free_skb(skb, rxrpc_skb_freed);
 624	_leave(" [queued]");
 
 
 
 625}
 626
 627/*
 628 * Process a requested ACK.
 629 */
 630static void rxrpc_input_requested_ack(struct rxrpc_call *call,
 631				      ktime_t resp_time,
 632				      rxrpc_serial_t orig_serial,
 633				      rxrpc_serial_t ack_serial)
 634{
 635	struct rxrpc_skb_priv *sp;
 636	struct sk_buff *skb;
 637	ktime_t sent_at;
 638	int ix;
 
 
 639
 640	for (ix = 0; ix < RXRPC_RXTX_BUFF_SIZE; ix++) {
 641		skb = call->rxtx_buffer[ix];
 642		if (!skb)
 643			continue;
 
 
 
 
 644
 645		sent_at = skb->tstamp;
 646		smp_rmb(); /* Read timestamp before serial. */
 647		sp = rxrpc_skb(skb);
 648		if (sp->hdr.serial != orig_serial)
 649			continue;
 650		goto found;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 651	}
 
 652
 653	return;
 654
 655found:
 656	rxrpc_peer_add_rtt(call, rxrpc_rtt_rx_requested_ack,
 657			   orig_serial, ack_serial, sent_at, resp_time);
 658}
 659
 660/*
 661 * Process the response to a ping that we sent to find out if we lost an ACK.
 662 *
 663 * If we got back a ping response that indicates a lower tx_top than what we
 664 * had at the time of the ping transmission, we adjudge all the DATA packets
 665 * sent between the response tx_top and the ping-time tx_top to have been lost.
 666 */
 667static void rxrpc_input_check_for_lost_ack(struct rxrpc_call *call)
 668{
 669	rxrpc_seq_t top, bottom, seq;
 670	bool resend = false;
 
 
 
 
 
 671
 672	spin_lock_bh(&call->lock);
 
 
 
 
 
 
 
 
 
 
 
 673
 674	bottom = call->tx_hard_ack + 1;
 675	top = call->acks_lost_top;
 676	if (before(bottom, top)) {
 677		for (seq = bottom; before_eq(seq, top); seq++) {
 678			int ix = seq & RXRPC_RXTX_BUFF_MASK;
 679			u8 annotation = call->rxtx_annotations[ix];
 680			u8 anno_type = annotation & RXRPC_TX_ANNO_MASK;
 681
 682			if (anno_type != RXRPC_TX_ANNO_UNACK)
 683				continue;
 684			annotation &= ~RXRPC_TX_ANNO_MASK;
 685			annotation |= RXRPC_TX_ANNO_RETRANS;
 686			call->rxtx_annotations[ix] = annotation;
 687			resend = true;
 688		}
 
 
 
 
 
 689	}
 690
 691	spin_unlock_bh(&call->lock);
 
 
 
 
 692
 693	if (resend && !test_and_set_bit(RXRPC_CALL_EV_RESEND, &call->events))
 694		rxrpc_queue_call(call);
 
 
 695}
 696
 697/*
 698 * Process a ping response.
 699 */
 700static void rxrpc_input_ping_response(struct rxrpc_call *call,
 701				      ktime_t resp_time,
 702				      rxrpc_serial_t orig_serial,
 703				      rxrpc_serial_t ack_serial)
 
 704{
 705	rxrpc_serial_t ping_serial;
 706	ktime_t ping_time;
 
 
 
 707
 708	ping_time = call->ping_time;
 709	smp_rmb();
 710	ping_serial = READ_ONCE(call->ping_serial);
 711
 712	if (orig_serial == call->acks_lost_ping)
 713		rxrpc_input_check_for_lost_ack(call);
 
 714
 715	if (before(orig_serial, ping_serial) ||
 716	    !test_and_clear_bit(RXRPC_CALL_PINGING, &call->flags))
 717		return;
 718	if (after(orig_serial, ping_serial))
 719		return;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 720
 721	rxrpc_peer_add_rtt(call, rxrpc_rtt_rx_ping_response,
 722			   orig_serial, ack_serial, ping_time, resp_time);
 723}
 724
 725/*
 726 * Process the extra information that may be appended to an ACK packet
 727 */
 728static void rxrpc_input_ackinfo(struct rxrpc_call *call, struct sk_buff *skb,
 729				struct rxrpc_ackinfo *ackinfo)
 730{
 731	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 732	struct rxrpc_peer *peer;
 733	unsigned int mtu;
 734	bool wake = false;
 735	u32 rwind = ntohl(ackinfo->rwind);
 736
 737	_proto("Rx ACK %%%u Info { rx=%u max=%u rwin=%u jm=%u }",
 738	       sp->hdr.serial,
 739	       ntohl(ackinfo->rxMTU), ntohl(ackinfo->maxMTU),
 740	       rwind, ntohl(ackinfo->jumbo_max));
 741
 742	if (call->tx_winsize != rwind) {
 743		if (rwind > RXRPC_RXTX_BUFF_SIZE - 1)
 744			rwind = RXRPC_RXTX_BUFF_SIZE - 1;
 745		if (rwind > call->tx_winsize)
 746			wake = true;
 747		trace_rxrpc_rx_rwind_change(call, sp->hdr.serial,
 748					    ntohl(ackinfo->rwind), wake);
 749		call->tx_winsize = rwind;
 750	}
 751
 752	if (call->cong_ssthresh > rwind)
 753		call->cong_ssthresh = rwind;
 754
 755	mtu = min(ntohl(ackinfo->rxMTU), ntohl(ackinfo->maxMTU));
 756
 757	peer = call->peer;
 758	if (mtu < peer->maxdata) {
 759		spin_lock_bh(&peer->lock);
 760		peer->maxdata = mtu;
 761		peer->mtu = mtu + peer->hdrsize;
 762		spin_unlock_bh(&peer->lock);
 763		_net("Net MTU %u (maxdata %u)", peer->mtu, peer->maxdata);
 764	}
 765
 766	if (wake)
 767		wake_up(&call->waitq);
 768}
 769
 770/*
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 771 * Process individual soft ACKs.
 772 *
 773 * Each ACK in the array corresponds to one packet and can be either an ACK or
 774 * a NAK.  If we get find an explicitly NAK'd packet we resend immediately;
 775 * packets that lie beyond the end of the ACK list are scheduled for resend by
 776 * the timer on the basis that the peer might just not have processed them at
 777 * the time the ACK was sent.
 778 */
 779static void rxrpc_input_soft_acks(struct rxrpc_call *call, u8 *acks,
 780				  rxrpc_seq_t seq, int nr_acks,
 781				  struct rxrpc_ack_summary *summary)
 782{
 783	int ix;
 784	u8 annotation, anno_type;
 785
 786	for (; nr_acks > 0; nr_acks--, seq++) {
 787		ix = seq & RXRPC_RXTX_BUFF_MASK;
 788		annotation = call->rxtx_annotations[ix];
 789		anno_type = annotation & RXRPC_TX_ANNO_MASK;
 790		annotation &= ~RXRPC_TX_ANNO_MASK;
 791		switch (*acks++) {
 792		case RXRPC_ACK_TYPE_ACK:
 793			summary->nr_acks++;
 794			if (anno_type == RXRPC_TX_ANNO_ACK)
 795				continue;
 796			summary->nr_new_acks++;
 797			call->rxtx_annotations[ix] =
 798				RXRPC_TX_ANNO_ACK | annotation;
 799			break;
 800		case RXRPC_ACK_TYPE_NACK:
 801			if (!summary->nr_nacks &&
 802			    call->acks_lowest_nak != seq) {
 803				call->acks_lowest_nak = seq;
 804				summary->new_low_nack = true;
 805			}
 806			summary->nr_nacks++;
 807			if (anno_type == RXRPC_TX_ANNO_NAK)
 808				continue;
 809			summary->nr_new_nacks++;
 810			if (anno_type == RXRPC_TX_ANNO_RETRANS)
 811				continue;
 812			call->rxtx_annotations[ix] =
 813				RXRPC_TX_ANNO_NAK | annotation;
 814			break;
 815		default:
 816			return rxrpc_proto_abort("SFT", call, 0);
 817		}
 
 
 
 
 
 
 818	}
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 819}
 820
 821/*
 822 * Process an ACK packet.
 823 *
 824 * ack.firstPacket is the sequence number of the first soft-ACK'd/NAK'd packet
 825 * in the ACK array.  Anything before that is hard-ACK'd and may be discarded.
 826 *
 827 * A hard-ACK means that a packet has been processed and may be discarded; a
 828 * soft-ACK means that the packet may be discarded and retransmission
 829 * requested.  A phase is complete when all packets are hard-ACK'd.
 830 */
 831static void rxrpc_input_ack(struct rxrpc_call *call, struct sk_buff *skb)
 832{
 833	struct rxrpc_ack_summary summary = { 0 };
 
 834	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 835	union {
 836		struct rxrpc_ackpacket ack;
 837		struct rxrpc_ackinfo info;
 838		u8 acks[RXRPC_MAXACKS];
 839	} buf;
 840	rxrpc_serial_t acked_serial;
 841	rxrpc_seq_t first_soft_ack, hard_ack, prev_pkt;
 842	int nr_acks, offset, ioffset;
 843
 844	_enter("");
 845
 846	offset = sizeof(struct rxrpc_wire_header);
 847	if (skb_copy_bits(skb, offset, &buf.ack, sizeof(buf.ack)) < 0) {
 848		_debug("extraction failure");
 849		return rxrpc_proto_abort("XAK", call, 0);
 850	}
 851	offset += sizeof(buf.ack);
 852
 853	acked_serial = ntohl(buf.ack.serial);
 854	first_soft_ack = ntohl(buf.ack.firstPacket);
 855	prev_pkt = ntohl(buf.ack.previousPacket);
 856	hard_ack = first_soft_ack - 1;
 857	nr_acks = buf.ack.nAcks;
 858	summary.ack_reason = (buf.ack.reason < RXRPC_ACK__INVALID ?
 859			      buf.ack.reason : RXRPC_ACK__INVALID);
 
 
 860
 861	trace_rxrpc_rx_ack(call, sp->hdr.serial, acked_serial,
 862			   first_soft_ack, prev_pkt,
 863			   summary.ack_reason, nr_acks);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 864
 865	if (buf.ack.reason == RXRPC_ACK_PING_RESPONSE)
 866		rxrpc_input_ping_response(call, skb->tstamp, acked_serial,
 867					  sp->hdr.serial);
 868	if (buf.ack.reason == RXRPC_ACK_REQUESTED)
 869		rxrpc_input_requested_ack(call, skb->tstamp, acked_serial,
 870					  sp->hdr.serial);
 871
 872	if (buf.ack.reason == RXRPC_ACK_PING) {
 873		_proto("Rx ACK %%%u PING Request", sp->hdr.serial);
 874		rxrpc_propose_ACK(call, RXRPC_ACK_PING_RESPONSE,
 875				  sp->hdr.serial, true, true,
 876				  rxrpc_propose_ack_respond_to_ping);
 877	} else if (sp->hdr.flags & RXRPC_REQUEST_ACK) {
 878		rxrpc_propose_ACK(call, RXRPC_ACK_REQUESTED,
 879				  sp->hdr.serial, true, true,
 880				  rxrpc_propose_ack_respond_to_ack);
 
 
 
 
 
 
 
 
 
 881	}
 882
 883	/* Discard any out-of-order or duplicate ACKs (outside lock). */
 884	if (before(first_soft_ack, call->ackr_first_seq) ||
 885	    before(prev_pkt, call->ackr_prev_seq))
 886		return;
 
 
 
 887
 888	buf.info.rxMTU = 0;
 889	ioffset = offset + nr_acks + 3;
 890	if (skb->len >= ioffset + sizeof(buf.info) &&
 891	    skb_copy_bits(skb, ioffset, &buf.info, sizeof(buf.info)) < 0)
 892		return rxrpc_proto_abort("XAI", call, 0);
 893
 894	spin_lock(&call->input_lock);
 895
 896	/* Discard any out-of-order or duplicate ACKs (inside lock). */
 897	if (before(first_soft_ack, call->ackr_first_seq) ||
 898	    before(prev_pkt, call->ackr_prev_seq))
 899		goto out;
 
 
 
 
 
 
 
 900	call->acks_latest_ts = skb->tstamp;
 901	call->acks_latest = sp->hdr.serial;
 
 902
 903	call->ackr_first_seq = first_soft_ack;
 904	call->ackr_prev_seq = prev_pkt;
 
 
 
 
 
 
 905
 906	/* Parse rwind and mtu sizes if provided. */
 907	if (buf.info.rxMTU)
 908		rxrpc_input_ackinfo(call, skb, &buf.info);
 909
 910	if (first_soft_ack == 0) {
 911		rxrpc_proto_abort("AK0", call, 0);
 912		goto out;
 913	}
 914
 915	/* Ignore ACKs unless we are or have just been transmitting. */
 916	switch (READ_ONCE(call->state)) {
 917	case RXRPC_CALL_CLIENT_SEND_REQUEST:
 918	case RXRPC_CALL_CLIENT_AWAIT_REPLY:
 919	case RXRPC_CALL_SERVER_SEND_REPLY:
 920	case RXRPC_CALL_SERVER_AWAIT_ACK:
 921		break;
 922	default:
 923		goto out;
 924	}
 925
 926	if (before(hard_ack, call->tx_hard_ack) ||
 927	    after(hard_ack, call->tx_top)) {
 928		rxrpc_proto_abort("AKW", call, 0);
 929		goto out;
 930	}
 931	if (nr_acks > call->tx_top - hard_ack) {
 932		rxrpc_proto_abort("AKN", call, 0);
 933		goto out;
 934	}
 935
 936	if (after(hard_ack, call->tx_hard_ack)) {
 937		if (rxrpc_rotate_tx_window(call, hard_ack, &summary)) {
 938			rxrpc_end_tx_phase(call, false, "ETA");
 939			goto out;
 940		}
 941	}
 942
 943	if (nr_acks > 0) {
 944		if (skb_copy_bits(skb, offset, buf.acks, nr_acks) < 0) {
 945			rxrpc_proto_abort("XSA", call, 0);
 946			goto out;
 947		}
 948		rxrpc_input_soft_acks(call, buf.acks, first_soft_ack, nr_acks,
 949				      &summary);
 950	}
 951
 952	if (call->rxtx_annotations[call->tx_top & RXRPC_RXTX_BUFF_MASK] &
 953	    RXRPC_TX_ANNO_LAST &&
 954	    summary.nr_acks == call->tx_top - hard_ack &&
 955	    rxrpc_is_client_call(call))
 956		rxrpc_propose_ACK(call, RXRPC_ACK_PING, sp->hdr.serial,
 957				  false, true,
 958				  rxrpc_propose_ack_ping_for_lost_reply);
 959
 960	rxrpc_congestion_management(call, skb, &summary, acked_serial);
 961out:
 962	spin_unlock(&call->input_lock);
 
 
 
 
 
 
 963}
 964
 965/*
 966 * Process an ACKALL packet.
 967 */
 968static void rxrpc_input_ackall(struct rxrpc_call *call, struct sk_buff *skb)
 969{
 970	struct rxrpc_ack_summary summary = { 0 };
 971	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 972
 973	_proto("Rx ACKALL %%%u", sp->hdr.serial);
 974
 975	spin_lock(&call->input_lock);
 976
 977	if (rxrpc_rotate_tx_window(call, call->tx_top, &summary))
 978		rxrpc_end_tx_phase(call, false, "ETL");
 979
 980	spin_unlock(&call->input_lock);
 981}
 982
 983/*
 984 * Process an ABORT packet directed at a call.
 985 */
 986static void rxrpc_input_abort(struct rxrpc_call *call, struct sk_buff *skb)
 987{
 988	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 989	__be32 wtmp;
 990	u32 abort_code = RX_CALL_DEAD;
 991
 992	_enter("");
 993
 994	if (skb->len >= 4 &&
 995	    skb_copy_bits(skb, sizeof(struct rxrpc_wire_header),
 996			  &wtmp, sizeof(wtmp)) >= 0)
 997		abort_code = ntohl(wtmp);
 998
 999	trace_rxrpc_rx_abort(call, sp->hdr.serial, abort_code);
1000
1001	_proto("Rx ABORT %%%u { %x }", sp->hdr.serial, abort_code);
1002
1003	if (rxrpc_set_call_completion(call, RXRPC_CALL_REMOTELY_ABORTED,
1004				      abort_code, -ECONNABORTED))
1005		rxrpc_notify_socket(call);
1006}
1007
1008/*
1009 * Process an incoming call packet.
1010 */
1011static void rxrpc_input_call_packet(struct rxrpc_call *call,
1012				    struct sk_buff *skb)
1013{
1014	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
1015	unsigned long timo;
1016
1017	_enter("%p,%p", call, skb);
1018
 
 
 
 
 
 
 
1019	timo = READ_ONCE(call->next_rx_timo);
1020	if (timo) {
1021		unsigned long now = jiffies, expect_rx_by;
1022
1023		expect_rx_by = now + timo;
1024		WRITE_ONCE(call->expect_rx_by, expect_rx_by);
1025		rxrpc_reduce_call_timer(call, expect_rx_by, now,
1026					rxrpc_timer_set_for_normal);
1027	}
1028
1029	switch (sp->hdr.type) {
1030	case RXRPC_PACKET_TYPE_DATA:
1031		rxrpc_input_data(call, skb);
1032		goto no_free;
1033
1034	case RXRPC_PACKET_TYPE_ACK:
1035		rxrpc_input_ack(call, skb);
1036		break;
1037
1038	case RXRPC_PACKET_TYPE_BUSY:
1039		_proto("Rx BUSY %%%u", sp->hdr.serial);
1040
1041		/* Just ignore BUSY packets from the server; the retry and
1042		 * lifespan timers will take care of business.  BUSY packets
1043		 * from the client don't make sense.
1044		 */
1045		break;
1046
1047	case RXRPC_PACKET_TYPE_ABORT:
1048		rxrpc_input_abort(call, skb);
1049		break;
1050
1051	case RXRPC_PACKET_TYPE_ACKALL:
1052		rxrpc_input_ackall(call, skb);
1053		break;
1054
1055	default:
1056		break;
1057	}
1058
1059	rxrpc_free_skb(skb, rxrpc_skb_freed);
1060no_free:
1061	_leave("");
1062}
1063
1064/*
1065 * Handle a new service call on a channel implicitly completing the preceding
1066 * call on that channel.  This does not apply to client conns.
1067 *
1068 * TODO: If callNumber > call_id + 1, renegotiate security.
1069 */
1070static void rxrpc_input_implicit_end_call(struct rxrpc_sock *rx,
1071					  struct rxrpc_connection *conn,
1072					  struct rxrpc_call *call)
1073{
1074	switch (READ_ONCE(call->state)) {
1075	case RXRPC_CALL_SERVER_AWAIT_ACK:
1076		rxrpc_call_completed(call);
1077		/* Fall through */
1078	case RXRPC_CALL_COMPLETE:
1079		break;
1080	default:
1081		if (rxrpc_abort_call("IMP", call, 0, RX_CALL_DEAD, -ESHUTDOWN)) {
1082			set_bit(RXRPC_CALL_EV_ABORT, &call->events);
1083			rxrpc_queue_call(call);
1084		}
1085		trace_rxrpc_improper_term(call);
1086		break;
1087	}
1088
1089	spin_lock(&rx->incoming_lock);
1090	__rxrpc_disconnect_call(conn, call);
1091	spin_unlock(&rx->incoming_lock);
1092	rxrpc_notify_socket(call);
1093}
1094
1095/*
1096 * post connection-level events to the connection
1097 * - this includes challenges, responses, some aborts and call terminal packet
1098 *   retransmission.
1099 */
1100static void rxrpc_post_packet_to_conn(struct rxrpc_connection *conn,
1101				      struct sk_buff *skb)
1102{
1103	_enter("%p,%p", conn, skb);
1104
1105	skb_queue_tail(&conn->rx_queue, skb);
1106	rxrpc_queue_conn(conn);
1107}
1108
1109/*
1110 * post endpoint-level events to the local endpoint
1111 * - this includes debug and version messages
1112 */
1113static void rxrpc_post_packet_to_local(struct rxrpc_local *local,
1114				       struct sk_buff *skb)
1115{
1116	_enter("%p,%p", local, skb);
1117
1118	if (rxrpc_get_local_maybe(local)) {
1119		skb_queue_tail(&local->event_queue, skb);
1120		rxrpc_queue_local(local);
1121	} else {
1122		rxrpc_free_skb(skb, rxrpc_skb_freed);
1123	}
1124}
1125
1126/*
1127 * put a packet up for transport-level abort
1128 */
1129static void rxrpc_reject_packet(struct rxrpc_local *local, struct sk_buff *skb)
1130{
1131	CHECK_SLAB_OKAY(&local->usage);
1132
1133	if (rxrpc_get_local_maybe(local)) {
1134		skb_queue_tail(&local->reject_queue, skb);
1135		rxrpc_queue_local(local);
1136	} else {
1137		rxrpc_free_skb(skb, rxrpc_skb_freed);
1138	}
1139}
1140
1141/*
1142 * Extract the wire header from a packet and translate the byte order.
1143 */
1144static noinline
1145int rxrpc_extract_header(struct rxrpc_skb_priv *sp, struct sk_buff *skb)
1146{
1147	struct rxrpc_wire_header whdr;
1148
1149	/* dig out the RxRPC connection details */
1150	if (skb_copy_bits(skb, 0, &whdr, sizeof(whdr)) < 0) {
1151		trace_rxrpc_rx_eproto(NULL, sp->hdr.serial,
1152				      tracepoint_string("bad_hdr"));
1153		return -EBADMSG;
1154	}
1155
1156	memset(sp, 0, sizeof(*sp));
1157	sp->hdr.epoch		= ntohl(whdr.epoch);
1158	sp->hdr.cid		= ntohl(whdr.cid);
1159	sp->hdr.callNumber	= ntohl(whdr.callNumber);
1160	sp->hdr.seq		= ntohl(whdr.seq);
1161	sp->hdr.serial		= ntohl(whdr.serial);
1162	sp->hdr.flags		= whdr.flags;
1163	sp->hdr.type		= whdr.type;
1164	sp->hdr.userStatus	= whdr.userStatus;
1165	sp->hdr.securityIndex	= whdr.securityIndex;
1166	sp->hdr._rsvd		= ntohs(whdr._rsvd);
1167	sp->hdr.serviceId	= ntohs(whdr.serviceId);
1168	return 0;
1169}
1170
1171/*
1172 * handle data received on the local endpoint
1173 * - may be called in interrupt context
1174 *
1175 * [!] Note that as this is called from the encap_rcv hook, the socket is not
1176 * held locked by the caller and nothing prevents sk_user_data on the UDP from
1177 * being cleared in the middle of processing this function.
1178 *
1179 * Called with the RCU read lock held from the IP layer via UDP.
1180 */
1181int rxrpc_input_packet(struct sock *udp_sk, struct sk_buff *skb)
1182{
1183	struct rxrpc_local *local = rcu_dereference_sk_user_data(udp_sk);
1184	struct rxrpc_connection *conn;
1185	struct rxrpc_channel *chan;
1186	struct rxrpc_call *call = NULL;
1187	struct rxrpc_skb_priv *sp;
1188	struct rxrpc_peer *peer = NULL;
1189	struct rxrpc_sock *rx = NULL;
1190	unsigned int channel;
1191
1192	_enter("%p", udp_sk);
1193
1194	if (unlikely(!local)) {
1195		kfree_skb(skb);
1196		return 0;
1197	}
1198	if (skb->tstamp == 0)
1199		skb->tstamp = ktime_get_real();
1200
1201	rxrpc_new_skb(skb, rxrpc_skb_received);
1202
1203	skb_pull(skb, sizeof(struct udphdr));
1204
1205	/* The UDP protocol already released all skb resources;
1206	 * we are free to add our own data there.
1207	 */
1208	sp = rxrpc_skb(skb);
1209
1210	/* dig out the RxRPC connection details */
1211	if (rxrpc_extract_header(sp, skb) < 0)
1212		goto bad_message;
1213
1214	if (IS_ENABLED(CONFIG_AF_RXRPC_INJECT_LOSS)) {
1215		static int lose;
1216		if ((lose++ & 7) == 7) {
1217			trace_rxrpc_rx_lose(sp);
1218			rxrpc_free_skb(skb, rxrpc_skb_lost);
1219			return 0;
1220		}
1221	}
1222
1223	if (skb->tstamp == 0)
1224		skb->tstamp = ktime_get_real();
1225	trace_rxrpc_rx_packet(sp);
1226
1227	switch (sp->hdr.type) {
1228	case RXRPC_PACKET_TYPE_VERSION:
1229		if (rxrpc_to_client(sp))
1230			goto discard;
1231		rxrpc_post_packet_to_local(local, skb);
1232		goto out;
1233
1234	case RXRPC_PACKET_TYPE_BUSY:
1235		if (rxrpc_to_server(sp))
1236			goto discard;
1237		/* Fall through */
1238	case RXRPC_PACKET_TYPE_ACK:
1239	case RXRPC_PACKET_TYPE_ACKALL:
1240		if (sp->hdr.callNumber == 0)
1241			goto bad_message;
1242		/* Fall through */
1243	case RXRPC_PACKET_TYPE_ABORT:
1244		break;
1245
1246	case RXRPC_PACKET_TYPE_DATA:
1247		if (sp->hdr.callNumber == 0 ||
1248		    sp->hdr.seq == 0)
1249			goto bad_message;
1250		if (!rxrpc_validate_data(skb))
1251			goto bad_message;
1252
1253		/* Unshare the packet so that it can be modified for in-place
1254		 * decryption.
1255		 */
1256		if (sp->hdr.securityIndex != 0) {
1257			struct sk_buff *nskb = skb_unshare(skb, GFP_ATOMIC);
1258			if (!nskb) {
1259				rxrpc_eaten_skb(skb, rxrpc_skb_unshared_nomem);
1260				goto out;
1261			}
1262
1263			if (nskb != skb) {
1264				rxrpc_eaten_skb(skb, rxrpc_skb_received);
1265				skb = nskb;
1266				rxrpc_new_skb(skb, rxrpc_skb_unshared);
1267				sp = rxrpc_skb(skb);
1268			}
1269		}
1270		break;
1271
1272	case RXRPC_PACKET_TYPE_CHALLENGE:
1273		if (rxrpc_to_server(sp))
1274			goto discard;
1275		break;
1276	case RXRPC_PACKET_TYPE_RESPONSE:
1277		if (rxrpc_to_client(sp))
1278			goto discard;
1279		break;
1280
1281		/* Packet types 9-11 should just be ignored. */
1282	case RXRPC_PACKET_TYPE_PARAMS:
1283	case RXRPC_PACKET_TYPE_10:
1284	case RXRPC_PACKET_TYPE_11:
1285		goto discard;
1286
1287	default:
1288		_proto("Rx Bad Packet Type %u", sp->hdr.type);
1289		goto bad_message;
1290	}
1291
1292	if (sp->hdr.serviceId == 0)
1293		goto bad_message;
1294
1295	if (rxrpc_to_server(sp)) {
1296		/* Weed out packets to services we're not offering.  Packets
1297		 * that would begin a call are explicitly rejected and the rest
1298		 * are just discarded.
1299		 */
1300		rx = rcu_dereference(local->service);
1301		if (!rx || (sp->hdr.serviceId != rx->srx.srx_service &&
1302			    sp->hdr.serviceId != rx->second_service)) {
1303			if (sp->hdr.type == RXRPC_PACKET_TYPE_DATA &&
1304			    sp->hdr.seq == 1)
1305				goto unsupported_service;
1306			goto discard;
1307		}
1308	}
1309
1310	conn = rxrpc_find_connection_rcu(local, skb, &peer);
1311	if (conn) {
1312		if (sp->hdr.securityIndex != conn->security_ix)
1313			goto wrong_security;
1314
1315		if (sp->hdr.serviceId != conn->service_id) {
1316			int old_id;
1317
1318			if (!test_bit(RXRPC_CONN_PROBING_FOR_UPGRADE, &conn->flags))
1319				goto reupgrade;
1320			old_id = cmpxchg(&conn->service_id, conn->params.service_id,
1321					 sp->hdr.serviceId);
1322
1323			if (old_id != conn->params.service_id &&
1324			    old_id != sp->hdr.serviceId)
1325				goto reupgrade;
1326		}
1327
1328		if (sp->hdr.callNumber == 0) {
1329			/* Connection-level packet */
1330			_debug("CONN %p {%d}", conn, conn->debug_id);
1331			rxrpc_post_packet_to_conn(conn, skb);
1332			goto out;
1333		}
1334
1335		if ((int)sp->hdr.serial - (int)conn->hi_serial > 0)
1336			conn->hi_serial = sp->hdr.serial;
1337
1338		/* Call-bound packets are routed by connection channel. */
1339		channel = sp->hdr.cid & RXRPC_CHANNELMASK;
1340		chan = &conn->channels[channel];
1341
1342		/* Ignore really old calls */
1343		if (sp->hdr.callNumber < chan->last_call)
1344			goto discard;
1345
1346		if (sp->hdr.callNumber == chan->last_call) {
1347			if (chan->call ||
1348			    sp->hdr.type == RXRPC_PACKET_TYPE_ABORT)
1349				goto discard;
1350
1351			/* For the previous service call, if completed
1352			 * successfully, we discard all further packets.
1353			 */
1354			if (rxrpc_conn_is_service(conn) &&
1355			    chan->last_type == RXRPC_PACKET_TYPE_ACK)
1356				goto discard;
1357
1358			/* But otherwise we need to retransmit the final packet
1359			 * from data cached in the connection record.
1360			 */
1361			if (sp->hdr.type == RXRPC_PACKET_TYPE_DATA)
1362				trace_rxrpc_rx_data(chan->call_debug_id,
1363						    sp->hdr.seq,
1364						    sp->hdr.serial,
1365						    sp->hdr.flags, 0);
1366			rxrpc_post_packet_to_conn(conn, skb);
1367			goto out;
1368		}
1369
1370		call = rcu_dereference(chan->call);
1371
1372		if (sp->hdr.callNumber > chan->call_id) {
1373			if (rxrpc_to_client(sp))
1374				goto reject_packet;
1375			if (call)
1376				rxrpc_input_implicit_end_call(rx, conn, call);
1377			call = NULL;
1378		}
1379
1380		if (call) {
1381			if (sp->hdr.serviceId != call->service_id)
1382				call->service_id = sp->hdr.serviceId;
1383			if ((int)sp->hdr.serial - (int)call->rx_serial > 0)
1384				call->rx_serial = sp->hdr.serial;
1385			if (!test_bit(RXRPC_CALL_RX_HEARD, &call->flags))
1386				set_bit(RXRPC_CALL_RX_HEARD, &call->flags);
1387		}
1388	}
1389
1390	if (!call || atomic_read(&call->usage) == 0) {
1391		if (rxrpc_to_client(sp) ||
1392		    sp->hdr.type != RXRPC_PACKET_TYPE_DATA)
1393			goto bad_message;
1394		if (sp->hdr.seq != 1)
1395			goto discard;
1396		call = rxrpc_new_incoming_call(local, rx, skb);
1397		if (!call)
1398			goto reject_packet;
1399		rxrpc_send_ping(call, skb);
1400		mutex_unlock(&call->user_mutex);
1401	}
1402
1403	/* Process a call packet; this either discards or passes on the ref
1404	 * elsewhere.
1405	 */
1406	rxrpc_input_call_packet(call, skb);
1407	goto out;
1408
1409discard:
1410	rxrpc_free_skb(skb, rxrpc_skb_freed);
1411out:
1412	trace_rxrpc_rx_done(0, 0);
1413	return 0;
1414
1415wrong_security:
1416	trace_rxrpc_abort(0, "SEC", sp->hdr.cid, sp->hdr.callNumber, sp->hdr.seq,
1417			  RXKADINCONSISTENCY, EBADMSG);
1418	skb->priority = RXKADINCONSISTENCY;
1419	goto post_abort;
1420
1421unsupported_service:
1422	trace_rxrpc_abort(0, "INV", sp->hdr.cid, sp->hdr.callNumber, sp->hdr.seq,
1423			  RX_INVALID_OPERATION, EOPNOTSUPP);
1424	skb->priority = RX_INVALID_OPERATION;
1425	goto post_abort;
1426
1427reupgrade:
1428	trace_rxrpc_abort(0, "UPG", sp->hdr.cid, sp->hdr.callNumber, sp->hdr.seq,
1429			  RX_PROTOCOL_ERROR, EBADMSG);
1430	goto protocol_error;
1431
1432bad_message:
1433	trace_rxrpc_abort(0, "BAD", sp->hdr.cid, sp->hdr.callNumber, sp->hdr.seq,
1434			  RX_PROTOCOL_ERROR, EBADMSG);
1435protocol_error:
1436	skb->priority = RX_PROTOCOL_ERROR;
1437post_abort:
1438	skb->mark = RXRPC_SKB_MARK_REJECT_ABORT;
1439reject_packet:
1440	trace_rxrpc_rx_done(skb->mark, skb->priority);
1441	rxrpc_reject_packet(local, skb);
1442	_leave(" [badmsg]");
1443	return 0;
1444}
v6.8
   1// SPDX-License-Identifier: GPL-2.0-or-later
   2/* Processing of received RxRPC packets
   3 *
   4 * Copyright (C) 2020 Red Hat, Inc. All Rights Reserved.
   5 * Written by David Howells (dhowells@redhat.com)
   6 */
   7
   8#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
   9
 
 
 
 
 
 
 
 
 
 
 
 
 
 
  10#include "ar-internal.h"
  11
  12static void rxrpc_proto_abort(struct rxrpc_call *call, rxrpc_seq_t seq,
  13			      enum rxrpc_abort_reason why)
  14{
  15	rxrpc_abort_call(call, seq, RX_PROTOCOL_ERROR, -EBADMSG, why);
 
 
 
  16}
  17
  18/*
  19 * Do TCP-style congestion management [RFC 5681].
  20 */
  21static void rxrpc_congestion_management(struct rxrpc_call *call,
  22					struct sk_buff *skb,
  23					struct rxrpc_ack_summary *summary,
  24					rxrpc_serial_t acked_serial)
  25{
  26	enum rxrpc_congest_change change = rxrpc_cong_no_change;
  27	unsigned int cumulative_acks = call->cong_cumul_acks;
  28	unsigned int cwnd = call->cong_cwnd;
  29	bool resend = false;
  30
  31	summary->flight_size =
  32		(call->tx_top - call->acks_hard_ack) - summary->nr_acks;
  33
  34	if (test_and_clear_bit(RXRPC_CALL_RETRANS_TIMEOUT, &call->flags)) {
  35		summary->retrans_timeo = true;
  36		call->cong_ssthresh = max_t(unsigned int,
  37					    summary->flight_size / 2, 2);
  38		cwnd = 1;
  39		if (cwnd >= call->cong_ssthresh &&
  40		    call->cong_mode == RXRPC_CALL_SLOW_START) {
  41			call->cong_mode = RXRPC_CALL_CONGEST_AVOIDANCE;
  42			call->cong_tstamp = skb->tstamp;
  43			cumulative_acks = 0;
  44		}
  45	}
  46
  47	cumulative_acks += summary->nr_new_acks;
 
  48	if (cumulative_acks > 255)
  49		cumulative_acks = 255;
  50
 
  51	summary->cwnd = call->cong_cwnd;
  52	summary->ssthresh = call->cong_ssthresh;
  53	summary->cumulative_acks = cumulative_acks;
  54	summary->dup_acks = call->cong_dup_acks;
  55
  56	switch (call->cong_mode) {
  57	case RXRPC_CALL_SLOW_START:
  58		if (summary->saw_nacks)
  59			goto packet_loss_detected;
  60		if (summary->cumulative_acks > 0)
  61			cwnd += 1;
  62		if (cwnd >= call->cong_ssthresh) {
  63			call->cong_mode = RXRPC_CALL_CONGEST_AVOIDANCE;
  64			call->cong_tstamp = skb->tstamp;
  65		}
  66		goto out;
  67
  68	case RXRPC_CALL_CONGEST_AVOIDANCE:
  69		if (summary->saw_nacks)
  70			goto packet_loss_detected;
  71
  72		/* We analyse the number of packets that get ACK'd per RTT
  73		 * period and increase the window if we managed to fill it.
  74		 */
  75		if (call->peer->rtt_count == 0)
  76			goto out;
  77		if (ktime_before(skb->tstamp,
  78				 ktime_add_us(call->cong_tstamp,
  79					      call->peer->srtt_us >> 3)))
  80			goto out_no_clear_ca;
  81		change = rxrpc_cong_rtt_window_end;
  82		call->cong_tstamp = skb->tstamp;
  83		if (cumulative_acks >= cwnd)
  84			cwnd++;
  85		goto out;
  86
  87	case RXRPC_CALL_PACKET_LOSS:
  88		if (!summary->saw_nacks)
  89			goto resume_normality;
  90
  91		if (summary->new_low_nack) {
  92			change = rxrpc_cong_new_low_nack;
  93			call->cong_dup_acks = 1;
  94			if (call->cong_extra > 1)
  95				call->cong_extra = 1;
  96			goto send_extra_data;
  97		}
  98
  99		call->cong_dup_acks++;
 100		if (call->cong_dup_acks < 3)
 101			goto send_extra_data;
 102
 103		change = rxrpc_cong_begin_retransmission;
 104		call->cong_mode = RXRPC_CALL_FAST_RETRANSMIT;
 105		call->cong_ssthresh = max_t(unsigned int,
 106					    summary->flight_size / 2, 2);
 107		cwnd = call->cong_ssthresh + 3;
 108		call->cong_extra = 0;
 109		call->cong_dup_acks = 0;
 110		resend = true;
 111		goto out;
 112
 113	case RXRPC_CALL_FAST_RETRANSMIT:
 114		if (!summary->new_low_nack) {
 115			if (summary->nr_new_acks == 0)
 116				cwnd += 1;
 117			call->cong_dup_acks++;
 118			if (call->cong_dup_acks == 2) {
 119				change = rxrpc_cong_retransmit_again;
 120				call->cong_dup_acks = 0;
 121				resend = true;
 122			}
 123		} else {
 124			change = rxrpc_cong_progress;
 125			cwnd = call->cong_ssthresh;
 126			if (!summary->saw_nacks)
 127				goto resume_normality;
 128		}
 129		goto out;
 130
 131	default:
 132		BUG();
 133		goto out;
 134	}
 135
 136resume_normality:
 137	change = rxrpc_cong_cleared_nacks;
 138	call->cong_dup_acks = 0;
 139	call->cong_extra = 0;
 140	call->cong_tstamp = skb->tstamp;
 141	if (cwnd < call->cong_ssthresh)
 142		call->cong_mode = RXRPC_CALL_SLOW_START;
 143	else
 144		call->cong_mode = RXRPC_CALL_CONGEST_AVOIDANCE;
 145out:
 146	cumulative_acks = 0;
 147out_no_clear_ca:
 148	if (cwnd >= RXRPC_TX_MAX_WINDOW)
 149		cwnd = RXRPC_TX_MAX_WINDOW;
 150	call->cong_cwnd = cwnd;
 151	call->cong_cumul_acks = cumulative_acks;
 152	summary->mode = call->cong_mode;
 153	trace_rxrpc_congest(call, summary, acked_serial, change);
 154	if (resend)
 155		rxrpc_resend(call, skb);
 156	return;
 157
 158packet_loss_detected:
 159	change = rxrpc_cong_saw_nack;
 160	call->cong_mode = RXRPC_CALL_PACKET_LOSS;
 161	call->cong_dup_acks = 0;
 162	goto send_extra_data;
 163
 164send_extra_data:
 165	/* Send some previously unsent DATA if we have some to advance the ACK
 166	 * state.
 167	 */
 168	if (test_bit(RXRPC_CALL_TX_LAST, &call->flags) ||
 169	    summary->nr_acks != call->tx_top - call->acks_hard_ack) {
 
 170		call->cong_extra++;
 171		wake_up(&call->waitq);
 172	}
 173	goto out_no_clear_ca;
 174}
 175
 176/*
 177 * Degrade the congestion window if we haven't transmitted a packet for >1RTT.
 
 178 */
 179void rxrpc_congestion_degrade(struct rxrpc_call *call)
 180{
 181	ktime_t rtt, now;
 182
 183	if (call->cong_mode != RXRPC_CALL_SLOW_START &&
 184	    call->cong_mode != RXRPC_CALL_CONGEST_AVOIDANCE)
 185		return;
 186	if (__rxrpc_call_state(call) == RXRPC_CALL_CLIENT_AWAIT_REPLY)
 187		return;
 188
 189	rtt = ns_to_ktime(call->peer->srtt_us * (1000 / 8));
 190	now = ktime_get_real();
 191	if (!ktime_before(ktime_add(call->tx_last_sent, rtt), now))
 192		return;
 193
 194	trace_rxrpc_reset_cwnd(call, now);
 195	rxrpc_inc_stat(call->rxnet, stat_tx_data_cwnd_reset);
 196	call->tx_last_sent = now;
 197	call->cong_mode = RXRPC_CALL_SLOW_START;
 198	call->cong_ssthresh = max_t(unsigned int, call->cong_ssthresh,
 199				    call->cong_cwnd * 3 / 4);
 200	call->cong_cwnd = max_t(unsigned int, call->cong_cwnd / 2, RXRPC_MIN_CWND);
 201}
 202
 203/*
 204 * Apply a hard ACK by advancing the Tx window.
 205 */
 206static bool rxrpc_rotate_tx_window(struct rxrpc_call *call, rxrpc_seq_t to,
 207				   struct rxrpc_ack_summary *summary)
 208{
 209	struct rxrpc_txbuf *txb;
 210	bool rot_last = false;
 
 
 211
 212	list_for_each_entry_rcu(txb, &call->tx_buffer, call_link, false) {
 213		if (before_eq(txb->seq, call->acks_hard_ack))
 214			continue;
 215		if (test_bit(RXRPC_TXBUF_LAST, &txb->flags)) {
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 216			set_bit(RXRPC_CALL_TX_LAST, &call->flags);
 217			rot_last = true;
 218		}
 219		if (txb->seq == to)
 220			break;
 221	}
 222
 223	if (rot_last)
 224		set_bit(RXRPC_CALL_TX_ALL_ACKED, &call->flags);
 225
 226	_enter("%x,%x,%x,%d", to, call->acks_hard_ack, call->tx_top, rot_last);
 
 
 
 227
 228	if (call->acks_lowest_nak == call->acks_hard_ack) {
 229		call->acks_lowest_nak = to;
 230	} else if (after(to, call->acks_lowest_nak)) {
 231		summary->new_low_nack = true;
 232		call->acks_lowest_nak = to;
 233	}
 234
 235	smp_store_release(&call->acks_hard_ack, to);
 236
 237	trace_rxrpc_txqueue(call, (rot_last ?
 238				   rxrpc_txqueue_rotate_last :
 239				   rxrpc_txqueue_rotate));
 240	wake_up(&call->waitq);
 241	return rot_last;
 242}
 243
 244/*
 245 * End the transmission phase of a call.
 246 *
 247 * This occurs when we get an ACKALL packet, the first DATA packet of a reply,
 248 * or a final ACK packet.
 249 */
 250static void rxrpc_end_tx_phase(struct rxrpc_call *call, bool reply_begun,
 251			       enum rxrpc_abort_reason abort_why)
 252{
 
 
 253	ASSERT(test_bit(RXRPC_CALL_TX_LAST, &call->flags));
 254
 255	if (unlikely(call->cong_last_nack)) {
 256		rxrpc_free_skb(call->cong_last_nack, rxrpc_skb_put_last_nack);
 257		call->cong_last_nack = NULL;
 258	}
 259
 260	switch (__rxrpc_call_state(call)) {
 
 261	case RXRPC_CALL_CLIENT_SEND_REQUEST:
 262	case RXRPC_CALL_CLIENT_AWAIT_REPLY:
 263		if (reply_begun) {
 264			rxrpc_set_call_state(call, RXRPC_CALL_CLIENT_RECV_REPLY);
 265			trace_rxrpc_txqueue(call, rxrpc_txqueue_end);
 266			break;
 267		}
 268
 269		rxrpc_set_call_state(call, RXRPC_CALL_CLIENT_AWAIT_REPLY);
 270		trace_rxrpc_txqueue(call, rxrpc_txqueue_await_reply);
 271		break;
 272
 273	case RXRPC_CALL_SERVER_AWAIT_ACK:
 274		rxrpc_call_completed(call);
 275		trace_rxrpc_txqueue(call, rxrpc_txqueue_end);
 
 276		break;
 277
 278	default:
 279		kdebug("end_tx %s", rxrpc_call_states[__rxrpc_call_state(call)]);
 280		rxrpc_proto_abort(call, call->tx_top, abort_why);
 281		break;
 282	}
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 283}
 284
 285/*
 286 * Begin the reply reception phase of a call.
 287 */
 288static bool rxrpc_receiving_reply(struct rxrpc_call *call)
 289{
 290	struct rxrpc_ack_summary summary = { 0 };
 291	unsigned long now, timo;
 292	rxrpc_seq_t top = READ_ONCE(call->tx_top);
 293
 294	if (call->ackr_reason) {
 
 
 
 295		now = jiffies;
 296		timo = now + MAX_JIFFY_OFFSET;
 297
 298		WRITE_ONCE(call->delay_ack_at, timo);
 299		trace_rxrpc_timer(call, rxrpc_timer_init_for_reply, now);
 300	}
 301
 302	if (!test_bit(RXRPC_CALL_TX_LAST, &call->flags)) {
 303		if (!rxrpc_rotate_tx_window(call, top, &summary)) {
 304			rxrpc_proto_abort(call, top, rxrpc_eproto_early_reply);
 305			return false;
 306		}
 307	}
 308
 309	rxrpc_end_tx_phase(call, true, rxrpc_eproto_unexpected_reply);
 
 310	return true;
 311}
 312
 313/*
 314 * End the packet reception phase.
 
 
 
 
 
 
 
 
 
 315 */
 316static void rxrpc_end_rx_phase(struct rxrpc_call *call, rxrpc_serial_t serial)
 317{
 318	rxrpc_seq_t whigh = READ_ONCE(call->rx_highest_seq);
 
 
 
 319
 320	_enter("%d,%s", call->debug_id, rxrpc_call_states[__rxrpc_call_state(call)]);
 
 
 
 321
 322	trace_rxrpc_receive(call, rxrpc_receive_end, 0, whigh);
 
 323
 324	switch (__rxrpc_call_state(call)) {
 325	case RXRPC_CALL_CLIENT_RECV_REPLY:
 326		rxrpc_propose_delay_ACK(call, serial, rxrpc_propose_ack_terminal_ack);
 327		rxrpc_call_completed(call);
 328		break;
 
 
 
 
 329
 330	case RXRPC_CALL_SERVER_RECV_REQUEST:
 331		rxrpc_set_call_state(call, RXRPC_CALL_SERVER_ACK_REQUEST);
 332		call->expect_req_by = jiffies + MAX_JIFFY_OFFSET;
 333		rxrpc_propose_delay_ACK(call, serial, rxrpc_propose_ack_processing_op);
 334		break;
 335
 336	default:
 337		break;
 338	}
 339}
 340
 341static void rxrpc_input_update_ack_window(struct rxrpc_call *call,
 342					  rxrpc_seq_t window, rxrpc_seq_t wtop)
 343{
 344	call->ackr_window = window;
 345	call->ackr_wtop = wtop;
 346}
 347
 348/*
 349 * Push a DATA packet onto the Rx queue.
 
 
 
 
 
 
 
 
 
 
 350 */
 351static void rxrpc_input_queue_data(struct rxrpc_call *call, struct sk_buff *skb,
 352				   rxrpc_seq_t window, rxrpc_seq_t wtop,
 353				   enum rxrpc_receive_trace why)
 354{
 355	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 356	bool last = sp->hdr.flags & RXRPC_LAST_PACKET;
 
 357
 358	__skb_queue_tail(&call->recvmsg_queue, skb);
 359	rxrpc_input_update_ack_window(call, window, wtop);
 360	trace_rxrpc_receive(call, last ? why + 1 : why, sp->hdr.serial, sp->hdr.seq);
 361	if (last)
 362		rxrpc_end_rx_phase(call, sp->hdr.serial);
 
 
 
 363}
 364
 365/*
 366 * Process a DATA packet.
 
 367 */
 368static void rxrpc_input_data_one(struct rxrpc_call *call, struct sk_buff *skb,
 369				 bool *_notify)
 370{
 371	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 372	struct sk_buff *oos;
 373	rxrpc_serial_t serial = sp->hdr.serial;
 374	unsigned int sack = call->ackr_sack_base;
 375	rxrpc_seq_t window = call->ackr_window;
 376	rxrpc_seq_t wtop = call->ackr_wtop;
 377	rxrpc_seq_t wlimit = window + call->rx_winsize - 1;
 378	rxrpc_seq_t seq = sp->hdr.seq;
 379	bool last = sp->hdr.flags & RXRPC_LAST_PACKET;
 380	int ack_reason = -1;
 381
 382	rxrpc_inc_stat(call->rxnet, stat_rx_data);
 383	if (sp->hdr.flags & RXRPC_REQUEST_ACK)
 384		rxrpc_inc_stat(call->rxnet, stat_rx_data_reqack);
 385	if (sp->hdr.flags & RXRPC_JUMBO_PACKET)
 386		rxrpc_inc_stat(call->rxnet, stat_rx_data_jumbo);
 387
 388	if (last) {
 389		if (test_and_set_bit(RXRPC_CALL_RX_LAST, &call->flags) &&
 390		    seq + 1 != wtop)
 391			return rxrpc_proto_abort(call, seq, rxrpc_eproto_different_last);
 392	} else {
 393		if (test_bit(RXRPC_CALL_RX_LAST, &call->flags) &&
 394		    after_eq(seq, wtop)) {
 395			pr_warn("Packet beyond last: c=%x q=%x window=%x-%x wlimit=%x\n",
 396				call->debug_id, seq, window, wtop, wlimit);
 397			return rxrpc_proto_abort(call, seq, rxrpc_eproto_data_after_last);
 
 
 
 398		}
 399	}
 400
 401	if (after(seq, call->rx_highest_seq))
 402		call->rx_highest_seq = seq;
 403
 404	trace_rxrpc_rx_data(call->debug_id, seq, serial, sp->hdr.flags);
 405
 406	if (before(seq, window)) {
 407		ack_reason = RXRPC_ACK_DUPLICATE;
 408		goto send_ack;
 409	}
 410	if (after(seq, wlimit)) {
 411		ack_reason = RXRPC_ACK_EXCEEDS_WINDOW;
 412		goto send_ack;
 
 
 
 
 
 
 
 
 413	}
 414
 415	/* Queue the packet. */
 416	if (seq == window) {
 417		if (sp->hdr.flags & RXRPC_REQUEST_ACK)
 418			ack_reason = RXRPC_ACK_REQUESTED;
 419		/* Send an immediate ACK if we fill in a hole */
 420		else if (!skb_queue_empty(&call->rx_oos_queue))
 421			ack_reason = RXRPC_ACK_DELAY;
 422		else
 423			call->ackr_nr_unacked++;
 424
 425		window++;
 426		if (after(window, wtop)) {
 427			trace_rxrpc_sack(call, seq, sack, rxrpc_sack_none);
 428			wtop = window;
 
 
 
 429		} else {
 430			trace_rxrpc_sack(call, seq, sack, rxrpc_sack_advance);
 431			sack = (sack + 1) % RXRPC_SACK_SIZE;
 
 
 
 432		}
 433
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 434
 435		rxrpc_get_skb(skb, rxrpc_skb_get_to_recvmsg);
 
 
 
 
 
 
 
 
 
 436
 437		spin_lock(&call->recvmsg_queue.lock);
 438		rxrpc_input_queue_data(call, skb, window, wtop, rxrpc_receive_queue);
 439		*_notify = true;
 
 
 
 
 
 
 440
 441		while ((oos = skb_peek(&call->rx_oos_queue))) {
 442			struct rxrpc_skb_priv *osp = rxrpc_skb(oos);
 443
 444			if (after(osp->hdr.seq, window))
 445				break;
 446
 447			__skb_unlink(oos, &call->rx_oos_queue);
 448			last = osp->hdr.flags & RXRPC_LAST_PACKET;
 449			seq = osp->hdr.seq;
 450			call->ackr_sack_table[sack] = 0;
 451			trace_rxrpc_sack(call, seq, sack, rxrpc_sack_fill);
 452			sack = (sack + 1) % RXRPC_SACK_SIZE;
 453
 454			window++;
 455			rxrpc_input_queue_data(call, oos, window, wtop,
 456					       rxrpc_receive_queue_oos);
 457		}
 458
 459		spin_unlock(&call->recvmsg_queue.lock);
 460
 461		call->ackr_sack_base = sack;
 462	} else {
 463		unsigned int slot;
 464
 465		ack_reason = RXRPC_ACK_OUT_OF_SEQUENCE;
 466
 467		slot = seq - window;
 468		sack = (sack + slot) % RXRPC_SACK_SIZE;
 469
 470		if (call->ackr_sack_table[sack % RXRPC_SACK_SIZE]) {
 471			ack_reason = RXRPC_ACK_DUPLICATE;
 472			goto send_ack;
 
 
 
 
 
 
 
 
 473		}
 474
 475		call->ackr_sack_table[sack % RXRPC_SACK_SIZE] |= 1;
 476		trace_rxrpc_sack(call, seq, sack, rxrpc_sack_oos);
 477
 478		if (after(seq + 1, wtop)) {
 479			wtop = seq + 1;
 480			rxrpc_input_update_ack_window(call, window, wtop);
 
 
 
 
 
 
 
 
 
 
 
 481		}
 482
 483		skb_queue_walk(&call->rx_oos_queue, oos) {
 484			struct rxrpc_skb_priv *osp = rxrpc_skb(oos);
 485
 486			if (after(osp->hdr.seq, seq)) {
 487				rxrpc_get_skb(skb, rxrpc_skb_get_to_recvmsg_oos);
 488				__skb_queue_before(&call->rx_oos_queue, oos, skb);
 489				goto oos_queued;
 490			}
 
 491		}
 
 492
 493		rxrpc_get_skb(skb, rxrpc_skb_get_to_recvmsg_oos);
 494		__skb_queue_tail(&call->rx_oos_queue, skb);
 495	oos_queued:
 496		trace_rxrpc_receive(call, last ? rxrpc_receive_oos_last : rxrpc_receive_oos,
 497				    sp->hdr.serial, sp->hdr.seq);
 
 
 
 
 
 
 
 
 498	}
 499
 500send_ack:
 501	if (ack_reason >= 0)
 502		rxrpc_send_ACK(call, ack_reason, serial,
 503			       rxrpc_propose_ack_input_data);
 504	else
 505		rxrpc_propose_delay_ACK(call, serial,
 506					rxrpc_propose_ack_input_data);
 507}
 508
 509/*
 510 * Split a jumbo packet and file the bits separately.
 511 */
 512static bool rxrpc_input_split_jumbo(struct rxrpc_call *call, struct sk_buff *skb)
 
 
 
 513{
 514	struct rxrpc_jumbo_header jhdr;
 515	struct rxrpc_skb_priv *sp = rxrpc_skb(skb), *jsp;
 516	struct sk_buff *jskb;
 517	unsigned int offset = sizeof(struct rxrpc_wire_header);
 518	unsigned int len = skb->len - offset;
 519	bool notify = false;
 520
 521	while (sp->hdr.flags & RXRPC_JUMBO_PACKET) {
 522		if (len < RXRPC_JUMBO_SUBPKTLEN)
 523			goto protocol_error;
 524		if (sp->hdr.flags & RXRPC_LAST_PACKET)
 525			goto protocol_error;
 526		if (skb_copy_bits(skb, offset + RXRPC_JUMBO_DATALEN,
 527				  &jhdr, sizeof(jhdr)) < 0)
 528			goto protocol_error;
 529
 530		jskb = skb_clone(skb, GFP_NOFS);
 531		if (!jskb) {
 532			kdebug("couldn't clone");
 533			return false;
 534		}
 535		rxrpc_new_skb(jskb, rxrpc_skb_new_jumbo_subpacket);
 536		jsp = rxrpc_skb(jskb);
 537		jsp->offset = offset;
 538		jsp->len = RXRPC_JUMBO_DATALEN;
 539		rxrpc_input_data_one(call, jskb, &notify);
 540		rxrpc_free_skb(jskb, rxrpc_skb_put_jumbo_subpacket);
 541
 542		sp->hdr.flags = jhdr.flags;
 543		sp->hdr._rsvd = ntohs(jhdr._rsvd);
 544		sp->hdr.seq++;
 545		sp->hdr.serial++;
 546		offset += RXRPC_JUMBO_SUBPKTLEN;
 547		len -= RXRPC_JUMBO_SUBPKTLEN;
 548	}
 549
 550	sp->offset = offset;
 551	sp->len    = len;
 552	rxrpc_input_data_one(call, skb, &notify);
 553	if (notify) {
 554		trace_rxrpc_notify_socket(call->debug_id, sp->hdr.serial);
 555		rxrpc_notify_socket(call);
 556	}
 557	return true;
 558
 559protocol_error:
 560	return false;
 
 
 
 561}
 562
 563/*
 564 * Process a DATA packet, adding the packet to the Rx ring.  The caller's
 565 * packet ref must be passed on or discarded.
 
 
 
 566 */
 567static void rxrpc_input_data(struct rxrpc_call *call, struct sk_buff *skb)
 568{
 569	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 570	rxrpc_serial_t serial = sp->hdr.serial;
 571	rxrpc_seq_t seq0 = sp->hdr.seq;
 572
 573	_enter("{%x,%x,%x},{%u,%x}",
 574	       call->ackr_window, call->ackr_wtop, call->rx_highest_seq,
 575	       skb->len, seq0);
 576
 577	if (__rxrpc_call_is_complete(call))
 578		return;
 579
 580	switch (__rxrpc_call_state(call)) {
 581	case RXRPC_CALL_CLIENT_SEND_REQUEST:
 582	case RXRPC_CALL_CLIENT_AWAIT_REPLY:
 583		/* Received data implicitly ACKs all of the request
 584		 * packets we sent when we're acting as a client.
 585		 */
 586		if (!rxrpc_receiving_reply(call))
 587			goto out_notify;
 588		break;
 589
 590	case RXRPC_CALL_SERVER_RECV_REQUEST: {
 591		unsigned long timo = READ_ONCE(call->next_req_timo);
 592		unsigned long now, expect_req_by;
 
 
 
 
 593
 594		if (timo) {
 595			now = jiffies;
 596			expect_req_by = now + timo;
 597			WRITE_ONCE(call->expect_req_by, expect_req_by);
 598			rxrpc_reduce_call_timer(call, expect_req_by, now,
 599						rxrpc_timer_set_for_idle);
 600		}
 601		break;
 602	}
 603
 604	default:
 605		break;
 606	}
 607
 608	if (!rxrpc_input_split_jumbo(call, skb)) {
 609		rxrpc_proto_abort(call, sp->hdr.seq, rxrpc_badmsg_bad_jumbo);
 610		goto out_notify;
 611	}
 612	return;
 613
 614out_notify:
 615	trace_rxrpc_notify_socket(call->debug_id, serial);
 616	rxrpc_notify_socket(call);
 617	_leave(" [queued]");
 618}
 619
 620/*
 621 * See if there's a cached RTT probe to complete.
 622 */
 623static void rxrpc_complete_rtt_probe(struct rxrpc_call *call,
 624				     ktime_t resp_time,
 625				     rxrpc_serial_t acked_serial,
 626				     rxrpc_serial_t ack_serial,
 627				     enum rxrpc_rtt_rx_trace type)
 628{
 629	rxrpc_serial_t orig_serial;
 630	unsigned long avail;
 631	ktime_t sent_at;
 632	bool matched = false;
 633	int i;
 634
 635	avail = READ_ONCE(call->rtt_avail);
 636	smp_rmb(); /* Read avail bits before accessing data. */
 
 637
 638	for (i = 0; i < ARRAY_SIZE(call->rtt_serial); i++) {
 639		if (!test_bit(i + RXRPC_CALL_RTT_PEND_SHIFT, &avail))
 640			continue;
 641
 642		sent_at = call->rtt_sent_at[i];
 643		orig_serial = call->rtt_serial[i];
 644
 645		if (orig_serial == acked_serial) {
 646			clear_bit(i + RXRPC_CALL_RTT_PEND_SHIFT, &call->rtt_avail);
 647			smp_mb(); /* Read data before setting avail bit */
 648			set_bit(i, &call->rtt_avail);
 649			rxrpc_peer_add_rtt(call, type, i, acked_serial, ack_serial,
 650					   sent_at, resp_time);
 651			matched = true;
 652		}
 653
 654		/* If a later serial is being acked, then mark this slot as
 655		 * being available.
 656		 */
 657		if (after(acked_serial, orig_serial)) {
 658			trace_rxrpc_rtt_rx(call, rxrpc_rtt_rx_obsolete, i,
 659					   orig_serial, acked_serial, 0, 0);
 660			clear_bit(i + RXRPC_CALL_RTT_PEND_SHIFT, &call->rtt_avail);
 661			smp_wmb();
 662			set_bit(i, &call->rtt_avail);
 663		}
 664	}
 665
 666	if (!matched)
 667		trace_rxrpc_rtt_rx(call, rxrpc_rtt_rx_lost, 9, 0, acked_serial, 0, 0);
 668}
 669
 670/*
 671 * Process the extra information that may be appended to an ACK packet
 672 */
 673static void rxrpc_input_ackinfo(struct rxrpc_call *call, struct sk_buff *skb,
 674				struct rxrpc_ackinfo *ackinfo)
 675{
 676	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 677	struct rxrpc_peer *peer;
 678	unsigned int mtu;
 679	bool wake = false;
 680	u32 rwind = ntohl(ackinfo->rwind);
 681
 682	if (rwind > RXRPC_TX_MAX_WINDOW)
 683		rwind = RXRPC_TX_MAX_WINDOW;
 
 
 
 684	if (call->tx_winsize != rwind) {
 
 
 685		if (rwind > call->tx_winsize)
 686			wake = true;
 687		trace_rxrpc_rx_rwind_change(call, sp->hdr.serial, rwind, wake);
 
 688		call->tx_winsize = rwind;
 689	}
 690
 691	if (call->cong_ssthresh > rwind)
 692		call->cong_ssthresh = rwind;
 693
 694	mtu = min(ntohl(ackinfo->rxMTU), ntohl(ackinfo->maxMTU));
 695
 696	peer = call->peer;
 697	if (mtu < peer->maxdata) {
 698		spin_lock(&peer->lock);
 699		peer->maxdata = mtu;
 700		peer->mtu = mtu + peer->hdrsize;
 701		spin_unlock(&peer->lock);
 
 702	}
 703
 704	if (wake)
 705		wake_up(&call->waitq);
 706}
 707
 708/*
 709 * Determine how many nacks from the previous ACK have now been satisfied.
 710 */
 711static rxrpc_seq_t rxrpc_input_check_prev_ack(struct rxrpc_call *call,
 712					      struct rxrpc_ack_summary *summary,
 713					      rxrpc_seq_t seq)
 714{
 715	struct sk_buff *skb = call->cong_last_nack;
 716	struct rxrpc_ackpacket ack;
 717	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 718	unsigned int i, new_acks = 0, retained_nacks = 0;
 719	rxrpc_seq_t old_seq = sp->first_ack;
 720	u8 *acks = skb->data + sizeof(struct rxrpc_wire_header) + sizeof(ack);
 721
 722	if (after_eq(seq, old_seq + sp->nr_acks)) {
 723		summary->nr_new_acks += sp->nr_nacks;
 724		summary->nr_new_acks += seq - (old_seq + sp->nr_acks);
 725		summary->nr_retained_nacks = 0;
 726	} else if (seq == old_seq) {
 727		summary->nr_retained_nacks = sp->nr_nacks;
 728	} else {
 729		for (i = 0; i < sp->nr_acks; i++) {
 730			if (acks[i] == RXRPC_ACK_TYPE_NACK) {
 731				if (before(old_seq + i, seq))
 732					new_acks++;
 733				else
 734					retained_nacks++;
 735			}
 736		}
 737
 738		summary->nr_new_acks += new_acks;
 739		summary->nr_retained_nacks = retained_nacks;
 740	}
 741
 742	return old_seq + sp->nr_acks;
 743}
 744
 745/*
 746 * Process individual soft ACKs.
 747 *
 748 * Each ACK in the array corresponds to one packet and can be either an ACK or
 749 * a NAK.  If we get find an explicitly NAK'd packet we resend immediately;
 750 * packets that lie beyond the end of the ACK list are scheduled for resend by
 751 * the timer on the basis that the peer might just not have processed them at
 752 * the time the ACK was sent.
 753 */
 754static void rxrpc_input_soft_acks(struct rxrpc_call *call,
 755				  struct rxrpc_ack_summary *summary,
 756				  struct sk_buff *skb,
 757				  rxrpc_seq_t seq,
 758				  rxrpc_seq_t since)
 759{
 760	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 761	unsigned int i, old_nacks = 0;
 762	rxrpc_seq_t lowest_nak = seq + sp->nr_acks;
 763	u8 *acks = skb->data + sizeof(struct rxrpc_wire_header) + sizeof(struct rxrpc_ackpacket);
 764
 765	for (i = 0; i < sp->nr_acks; i++) {
 766		if (acks[i] == RXRPC_ACK_TYPE_ACK) {
 
 767			summary->nr_acks++;
 768			if (after_eq(seq, since))
 769				summary->nr_new_acks++;
 770		} else {
 771			summary->saw_nacks = true;
 772			if (before(seq, since)) {
 773				/* Overlap with previous ACK */
 774				old_nacks++;
 775			} else {
 776				summary->nr_new_nacks++;
 777				sp->nr_nacks++;
 
 778			}
 779
 780			if (before(seq, lowest_nak))
 781				lowest_nak = seq;
 
 
 
 
 
 
 
 
 782		}
 783		seq++;
 784	}
 785
 786	if (lowest_nak != call->acks_lowest_nak) {
 787		call->acks_lowest_nak = lowest_nak;
 788		summary->new_low_nack = true;
 789	}
 790
 791	/* We *can* have more nacks than we did - the peer is permitted to drop
 792	 * packets it has soft-acked and re-request them.  Further, it is
 793	 * possible for the nack distribution to change whilst the number of
 794	 * nacks stays the same or goes down.
 795	 */
 796	if (old_nacks < summary->nr_retained_nacks)
 797		summary->nr_new_acks += summary->nr_retained_nacks - old_nacks;
 798	summary->nr_retained_nacks = old_nacks;
 799}
 800
 801/*
 802 * Return true if the ACK is valid - ie. it doesn't appear to have regressed
 803 * with respect to the ack state conveyed by preceding ACKs.
 804 */
 805static bool rxrpc_is_ack_valid(struct rxrpc_call *call,
 806			       rxrpc_seq_t first_pkt, rxrpc_seq_t prev_pkt)
 807{
 808	rxrpc_seq_t base = READ_ONCE(call->acks_first_seq);
 809
 810	if (after(first_pkt, base))
 811		return true; /* The window advanced */
 812
 813	if (before(first_pkt, base))
 814		return false; /* firstPacket regressed */
 815
 816	if (after_eq(prev_pkt, call->acks_prev_seq))
 817		return true; /* previousPacket hasn't regressed. */
 818
 819	/* Some rx implementations put a serial number in previousPacket. */
 820	if (after_eq(prev_pkt, base + call->tx_winsize))
 821		return false;
 822	return true;
 823}
 824
 825/*
 826 * Process an ACK packet.
 827 *
 828 * ack.firstPacket is the sequence number of the first soft-ACK'd/NAK'd packet
 829 * in the ACK array.  Anything before that is hard-ACK'd and may be discarded.
 830 *
 831 * A hard-ACK means that a packet has been processed and may be discarded; a
 832 * soft-ACK means that the packet may be discarded and retransmission
 833 * requested.  A phase is complete when all packets are hard-ACK'd.
 834 */
 835static void rxrpc_input_ack(struct rxrpc_call *call, struct sk_buff *skb)
 836{
 837	struct rxrpc_ack_summary summary = { 0 };
 838	struct rxrpc_ackpacket ack;
 839	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 840	struct rxrpc_ackinfo info;
 841	rxrpc_serial_t ack_serial, acked_serial;
 842	rxrpc_seq_t first_soft_ack, hard_ack, prev_pkt, since;
 
 
 
 
 843	int nr_acks, offset, ioffset;
 844
 845	_enter("");
 846
 847	offset = sizeof(struct rxrpc_wire_header);
 848	if (skb_copy_bits(skb, offset, &ack, sizeof(ack)) < 0)
 849		return rxrpc_proto_abort(call, 0, rxrpc_badmsg_short_ack);
 850	offset += sizeof(ack);
 851
 852	ack_serial = sp->hdr.serial;
 853	acked_serial = ntohl(ack.serial);
 854	first_soft_ack = ntohl(ack.firstPacket);
 855	prev_pkt = ntohl(ack.previousPacket);
 
 856	hard_ack = first_soft_ack - 1;
 857	nr_acks = ack.nAcks;
 858	sp->first_ack = first_soft_ack;
 859	sp->nr_acks = nr_acks;
 860	summary.ack_reason = (ack.reason < RXRPC_ACK__INVALID ?
 861			      ack.reason : RXRPC_ACK__INVALID);
 862
 863	trace_rxrpc_rx_ack(call, ack_serial, acked_serial,
 864			   first_soft_ack, prev_pkt,
 865			   summary.ack_reason, nr_acks);
 866	rxrpc_inc_stat(call->rxnet, stat_rx_acks[ack.reason]);
 867
 868	if (acked_serial != 0) {
 869		switch (ack.reason) {
 870		case RXRPC_ACK_PING_RESPONSE:
 871			rxrpc_complete_rtt_probe(call, skb->tstamp, acked_serial, ack_serial,
 872						 rxrpc_rtt_rx_ping_response);
 873			break;
 874		case RXRPC_ACK_REQUESTED:
 875			rxrpc_complete_rtt_probe(call, skb->tstamp, acked_serial, ack_serial,
 876						 rxrpc_rtt_rx_requested_ack);
 877			break;
 878		default:
 879			rxrpc_complete_rtt_probe(call, skb->tstamp, acked_serial, ack_serial,
 880						 rxrpc_rtt_rx_other_ack);
 881			break;
 882		}
 883	}
 884
 885	/* If we get an EXCEEDS_WINDOW ACK from the server, it probably
 886	 * indicates that the client address changed due to NAT.  The server
 887	 * lost the call because it switched to a different peer.
 888	 */
 889	if (unlikely(ack.reason == RXRPC_ACK_EXCEEDS_WINDOW) &&
 890	    first_soft_ack == 1 &&
 891	    prev_pkt == 0 &&
 892	    rxrpc_is_client_call(call)) {
 893		rxrpc_set_call_completion(call, RXRPC_CALL_REMOTELY_ABORTED,
 894					  0, -ENETRESET);
 895		goto send_response;
 896	}
 897
 898	/* If we get an OUT_OF_SEQUENCE ACK from the server, that can also
 899	 * indicate a change of address.  However, we can retransmit the call
 900	 * if we still have it buffered to the beginning.
 901	 */
 902	if (unlikely(ack.reason == RXRPC_ACK_OUT_OF_SEQUENCE) &&
 903	    first_soft_ack == 1 &&
 904	    prev_pkt == 0 &&
 905	    call->acks_hard_ack == 0 &&
 906	    rxrpc_is_client_call(call)) {
 907		rxrpc_set_call_completion(call, RXRPC_CALL_REMOTELY_ABORTED,
 908					  0, -ENETRESET);
 909		goto send_response;
 910	}
 911
 912	/* Discard any out-of-order or duplicate ACKs (outside lock). */
 913	if (!rxrpc_is_ack_valid(call, first_soft_ack, prev_pkt)) {
 914		trace_rxrpc_rx_discard_ack(call->debug_id, ack_serial,
 915					   first_soft_ack, call->acks_first_seq,
 916					   prev_pkt, call->acks_prev_seq);
 917		goto send_response;
 918	}
 919
 920	info.rxMTU = 0;
 921	ioffset = offset + nr_acks + 3;
 922	if (skb->len >= ioffset + sizeof(info) &&
 923	    skb_copy_bits(skb, ioffset, &info, sizeof(info)) < 0)
 924		return rxrpc_proto_abort(call, 0, rxrpc_badmsg_short_ack_info);
 925
 926	if (nr_acks > 0)
 927		skb_condense(skb);
 928
 929	if (call->cong_last_nack) {
 930		since = rxrpc_input_check_prev_ack(call, &summary, first_soft_ack);
 931		rxrpc_free_skb(call->cong_last_nack, rxrpc_skb_put_last_nack);
 932		call->cong_last_nack = NULL;
 933	} else {
 934		summary.nr_new_acks = first_soft_ack - call->acks_first_seq;
 935		call->acks_lowest_nak = first_soft_ack + nr_acks;
 936		since = first_soft_ack;
 937	}
 938
 939	call->acks_latest_ts = skb->tstamp;
 940	call->acks_first_seq = first_soft_ack;
 941	call->acks_prev_seq = prev_pkt;
 942
 943	switch (ack.reason) {
 944	case RXRPC_ACK_PING:
 945		break;
 946	default:
 947		if (acked_serial && after(acked_serial, call->acks_highest_serial))
 948			call->acks_highest_serial = acked_serial;
 949		break;
 950	}
 951
 952	/* Parse rwind and mtu sizes if provided. */
 953	if (info.rxMTU)
 954		rxrpc_input_ackinfo(call, skb, &info);
 955
 956	if (first_soft_ack == 0)
 957		return rxrpc_proto_abort(call, 0, rxrpc_eproto_ackr_zero);
 
 
 958
 959	/* Ignore ACKs unless we are or have just been transmitting. */
 960	switch (__rxrpc_call_state(call)) {
 961	case RXRPC_CALL_CLIENT_SEND_REQUEST:
 962	case RXRPC_CALL_CLIENT_AWAIT_REPLY:
 963	case RXRPC_CALL_SERVER_SEND_REPLY:
 964	case RXRPC_CALL_SERVER_AWAIT_ACK:
 965		break;
 966	default:
 967		goto send_response;
 968	}
 969
 970	if (before(hard_ack, call->acks_hard_ack) ||
 971	    after(hard_ack, call->tx_top))
 972		return rxrpc_proto_abort(call, 0, rxrpc_eproto_ackr_outside_window);
 973	if (nr_acks > call->tx_top - hard_ack)
 974		return rxrpc_proto_abort(call, 0, rxrpc_eproto_ackr_sack_overflow);
 
 
 
 
 975
 976	if (after(hard_ack, call->acks_hard_ack)) {
 977		if (rxrpc_rotate_tx_window(call, hard_ack, &summary)) {
 978			rxrpc_end_tx_phase(call, false, rxrpc_eproto_unexpected_ack);
 979			goto send_response;
 980		}
 981	}
 982
 983	if (nr_acks > 0) {
 984		if (offset > (int)skb->len - nr_acks)
 985			return rxrpc_proto_abort(call, 0, rxrpc_eproto_ackr_short_sack);
 986		rxrpc_input_soft_acks(call, &summary, skb, first_soft_ack, since);
 987		rxrpc_get_skb(skb, rxrpc_skb_get_last_nack);
 988		call->cong_last_nack = skb;
 
 989	}
 990
 991	if (test_bit(RXRPC_CALL_TX_LAST, &call->flags) &&
 
 992	    summary.nr_acks == call->tx_top - hard_ack &&
 993	    rxrpc_is_client_call(call))
 994		rxrpc_propose_ping(call, ack_serial,
 995				   rxrpc_propose_ack_ping_for_lost_reply);
 
 996
 997	rxrpc_congestion_management(call, skb, &summary, acked_serial);
 998
 999send_response:
1000	if (ack.reason == RXRPC_ACK_PING)
1001		rxrpc_send_ACK(call, RXRPC_ACK_PING_RESPONSE, ack_serial,
1002			       rxrpc_propose_ack_respond_to_ping);
1003	else if (sp->hdr.flags & RXRPC_REQUEST_ACK)
1004		rxrpc_send_ACK(call, RXRPC_ACK_REQUESTED, ack_serial,
1005			       rxrpc_propose_ack_respond_to_ack);
1006}
1007
1008/*
1009 * Process an ACKALL packet.
1010 */
1011static void rxrpc_input_ackall(struct rxrpc_call *call, struct sk_buff *skb)
1012{
1013	struct rxrpc_ack_summary summary = { 0 };
 
 
 
 
 
1014
1015	if (rxrpc_rotate_tx_window(call, call->tx_top, &summary))
1016		rxrpc_end_tx_phase(call, false, rxrpc_eproto_unexpected_ackall);
 
 
1017}
1018
1019/*
1020 * Process an ABORT packet directed at a call.
1021 */
1022static void rxrpc_input_abort(struct rxrpc_call *call, struct sk_buff *skb)
1023{
1024	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 
 
1025
1026	trace_rxrpc_rx_abort(call, sp->hdr.serial, skb->priority);
 
 
 
 
 
 
 
1027
1028	rxrpc_set_call_completion(call, RXRPC_CALL_REMOTELY_ABORTED,
1029				  skb->priority, -ECONNABORTED);
 
 
 
1030}
1031
1032/*
1033 * Process an incoming call packet.
1034 */
1035void rxrpc_input_call_packet(struct rxrpc_call *call, struct sk_buff *skb)
 
1036{
1037	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
1038	unsigned long timo;
1039
1040	_enter("%p,%p", call, skb);
1041
1042	if (sp->hdr.serviceId != call->dest_srx.srx_service)
1043		call->dest_srx.srx_service = sp->hdr.serviceId;
1044	if ((int)sp->hdr.serial - (int)call->rx_serial > 0)
1045		call->rx_serial = sp->hdr.serial;
1046	if (!test_bit(RXRPC_CALL_RX_HEARD, &call->flags))
1047		set_bit(RXRPC_CALL_RX_HEARD, &call->flags);
1048
1049	timo = READ_ONCE(call->next_rx_timo);
1050	if (timo) {
1051		unsigned long now = jiffies, expect_rx_by;
1052
1053		expect_rx_by = now + timo;
1054		WRITE_ONCE(call->expect_rx_by, expect_rx_by);
1055		rxrpc_reduce_call_timer(call, expect_rx_by, now,
1056					rxrpc_timer_set_for_normal);
1057	}
1058
1059	switch (sp->hdr.type) {
1060	case RXRPC_PACKET_TYPE_DATA:
1061		return rxrpc_input_data(call, skb);
 
1062
1063	case RXRPC_PACKET_TYPE_ACK:
1064		return rxrpc_input_ack(call, skb);
 
1065
1066	case RXRPC_PACKET_TYPE_BUSY:
 
 
1067		/* Just ignore BUSY packets from the server; the retry and
1068		 * lifespan timers will take care of business.  BUSY packets
1069		 * from the client don't make sense.
1070		 */
1071		return;
1072
1073	case RXRPC_PACKET_TYPE_ABORT:
1074		return rxrpc_input_abort(call, skb);
 
1075
1076	case RXRPC_PACKET_TYPE_ACKALL:
1077		return rxrpc_input_ackall(call, skb);
 
1078
1079	default:
1080		break;
1081	}
 
 
 
 
1082}
1083
1084/*
1085 * Handle a new service call on a channel implicitly completing the preceding
1086 * call on that channel.  This does not apply to client conns.
1087 *
1088 * TODO: If callNumber > call_id + 1, renegotiate security.
1089 */
1090void rxrpc_implicit_end_call(struct rxrpc_call *call, struct sk_buff *skb)
 
 
1091{
1092	switch (__rxrpc_call_state(call)) {
1093	case RXRPC_CALL_SERVER_AWAIT_ACK:
1094		rxrpc_call_completed(call);
1095		fallthrough;
1096	case RXRPC_CALL_COMPLETE:
1097		break;
1098	default:
1099		rxrpc_abort_call(call, 0, RX_CALL_DEAD, -ESHUTDOWN,
1100				 rxrpc_eproto_improper_term);
 
 
1101		trace_rxrpc_improper_term(call);
1102		break;
1103	}
1104
1105	rxrpc_input_call_event(call, skb);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1106}