1 files changed, 945 insertions, 915 deletions

diff --git a/net/rxrpc/input.c b/net/rxrpc/input.c
index e56e23ed2229..24aceb183c2c 100644
--- a/net/rxrpc/input.c
+++ b/net/rxrpc/input.c
@@ -1,118 +1,94 @@
-/* RxRPC packet reception
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* Processing of received RxRPC packets
  *
- * Copyright (C) 2007, 2016 Red Hat, Inc. All Rights Reserved.
+ * Copyright (C) 2020 Red Hat, Inc. All Rights Reserved.
  * Written by David Howells (dhowells@redhat.com)
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public License
- * as published by the Free Software Foundation; either version
- * 2 of the License, or (at your option) any later version.
  */
 
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 
-#include <linux/module.h>
-#include <linux/net.h>
-#include <linux/skbuff.h>
-#include <linux/errqueue.h>
-#include <linux/udp.h>
-#include <linux/in.h>
-#include <linux/in6.h>
-#include <linux/icmp.h>
-#include <linux/gfp.h>
-#include <net/sock.h>
-#include <net/af_rxrpc.h>
-#include <net/ip.h>
-#include <net/udp.h>
-#include <net/net_namespace.h>
 #include "ar-internal.h"
 
-static void rxrpc_proto_abort(const char *why,
-			      struct rxrpc_call *call, rxrpc_seq_t seq)
+/* Override priority when generating ACKs for received DATA */
+static const u8 rxrpc_ack_priority[RXRPC_ACK__INVALID] = {
+	[RXRPC_ACK_IDLE]		= 1,
+	[RXRPC_ACK_DELAY]		= 2,
+	[RXRPC_ACK_REQUESTED]		= 3,
+	[RXRPC_ACK_DUPLICATE]		= 4,
+	[RXRPC_ACK_EXCEEDS_WINDOW]	= 5,
+	[RXRPC_ACK_NOSPACE]		= 6,
+	[RXRPC_ACK_OUT_OF_SEQUENCE]	= 7,
+};
+
+static void rxrpc_proto_abort(struct rxrpc_call *call, rxrpc_seq_t seq,
+			      enum rxrpc_abort_reason why)
 {
-	if (rxrpc_abort_call(why, call, seq, RX_PROTOCOL_ERROR, -EBADMSG)) {
-		set_bit(RXRPC_CALL_EV_ABORT, &call->events);
-		rxrpc_queue_call(call);
-	}
+	rxrpc_abort_call(call, seq, RX_PROTOCOL_ERROR, -EBADMSG, why);
 }
 
 /*
- * Do TCP-style congestion management [RFC 5681].
+ * Do TCP-style congestion management [RFC5681].
  */
 static void rxrpc_congestion_management(struct rxrpc_call *call,
-					struct sk_buff *skb,
-					struct rxrpc_ack_summary *summary,
-					rxrpc_serial_t acked_serial)
+					struct rxrpc_ack_summary *summary)
 {
-	enum rxrpc_congest_change change = rxrpc_cong_no_change;
-	unsigned int cumulative_acks = call->cong_cumul_acks;
-	unsigned int cwnd = call->cong_cwnd;
-	bool resend = false;
-
-	summary->flight_size =
-		(call->tx_top - call->tx_hard_ack) - summary->nr_acks;
+	summary->change = rxrpc_cong_no_change;
+	summary->in_flight = rxrpc_tx_in_flight(call);
 
 	if (test_and_clear_bit(RXRPC_CALL_RETRANS_TIMEOUT, &call->flags)) {
 		summary->retrans_timeo = true;
-		call->cong_ssthresh = max_t(unsigned int,
-					    summary->flight_size / 2, 2);
-		cwnd = 1;
-		if (cwnd >= call->cong_ssthresh &&
-		    call->cong_mode == RXRPC_CALL_SLOW_START) {
-			call->cong_mode = RXRPC_CALL_CONGEST_AVOIDANCE;
-			call->cong_tstamp = skb->tstamp;
-			cumulative_acks = 0;
+		call->cong_ssthresh = umax(summary->in_flight / 2, 2);
+		call->cong_cwnd = 1;
+		if (call->cong_cwnd >= call->cong_ssthresh &&
+		    call->cong_ca_state == RXRPC_CA_SLOW_START) {
+			call->cong_ca_state = RXRPC_CA_CONGEST_AVOIDANCE;
+			call->cong_tstamp = call->acks_latest_ts;
+			call->cong_cumul_acks = 0;
 		}
 	}
 
-	cumulative_acks += summary->nr_new_acks;
-	cumulative_acks += summary->nr_rot_new_acks;
-	if (cumulative_acks > 255)
-		cumulative_acks = 255;
+	call->cong_cumul_acks += summary->nr_new_sacks;
+	call->cong_cumul_acks += summary->nr_new_hacks;
+	if (call->cong_cumul_acks > 255)
+		call->cong_cumul_acks = 255;
 
-	summary->mode = call->cong_mode;
-	summary->cwnd = call->cong_cwnd;
-	summary->ssthresh = call->cong_ssthresh;
-	summary->cumulative_acks = cumulative_acks;
-	summary->dup_acks = call->cong_dup_acks;
-
-	switch (call->cong_mode) {
-	case RXRPC_CALL_SLOW_START:
-		if (summary->nr_nacks > 0)
+	switch (call->cong_ca_state) {
+	case RXRPC_CA_SLOW_START:
+		if (call->acks_nr_snacks > 0)
 			goto packet_loss_detected;
-		if (summary->cumulative_acks > 0)
-			cwnd += 1;
-		if (cwnd >= call->cong_ssthresh) {
-			call->cong_mode = RXRPC_CALL_CONGEST_AVOIDANCE;
-			call->cong_tstamp = skb->tstamp;
+		if (call->cong_cumul_acks > 0)
+			call->cong_cwnd += 1;
+		if (call->cong_cwnd >= call->cong_ssthresh) {
+			call->cong_ca_state = RXRPC_CA_CONGEST_AVOIDANCE;
+			call->cong_tstamp = call->acks_latest_ts;
 		}
 		goto out;
 
-	case RXRPC_CALL_CONGEST_AVOIDANCE:
-		if (summary->nr_nacks > 0)
+	case RXRPC_CA_CONGEST_AVOIDANCE:
+		if (call->acks_nr_snacks > 0)
 			goto packet_loss_detected;
 
 		/* We analyse the number of packets that get ACK'd per RTT
 		 * period and increase the window if we managed to fill it.
 		 */
-		if (call->peer->rtt_usage == 0)
+		if (call->rtt_count == 0)
 			goto out;
-		if (ktime_before(skb->tstamp,
-				 ktime_add_ns(call->cong_tstamp,
-					      call->peer->rtt)))
+		if (ktime_before(call->acks_latest_ts,
+				 ktime_add_us(call->cong_tstamp,
+					      call->srtt_us >> 3)))
 			goto out_no_clear_ca;
-		change = rxrpc_cong_rtt_window_end;
-		call->cong_tstamp = skb->tstamp;
-		if (cumulative_acks >= cwnd)
-			cwnd++;
+		summary->change = rxrpc_cong_rtt_window_end;
+		call->cong_tstamp = call->acks_latest_ts;
+		if (call->cong_cumul_acks >= call->cong_cwnd)
+			call->cong_cwnd++;
 		goto out;
 
-	case RXRPC_CALL_PACKET_LOSS:
-		if (summary->nr_nacks == 0)
+	case RXRPC_CA_PACKET_LOSS:
+		if (call->acks_nr_snacks == 0)
 			goto resume_normality;
 
-		if (summary->new_low_nack) {
-			change = rxrpc_cong_new_low_nack;
+		if (summary->new_low_snack) {
+			summary->change = rxrpc_cong_new_low_nack;
 			call->cong_dup_acks = 1;
 			if (call->cong_extra > 1)
 				call->cong_extra = 1;
@@ -123,31 +99,35 @@ static void rxrpc_congestion_management(struct rxrpc_call *call,
 		if (call->cong_dup_acks < 3)
 			goto send_extra_data;
 
-		change = rxrpc_cong_begin_retransmission;
-		call->cong_mode = RXRPC_CALL_FAST_RETRANSMIT;
-		call->cong_ssthresh = max_t(unsigned int,
-					    summary->flight_size / 2, 2);
-		cwnd = call->cong_ssthresh + 3;
+		summary->change = rxrpc_cong_begin_retransmission;
+		call->cong_ca_state = RXRPC_CA_FAST_RETRANSMIT;
+		call->cong_ssthresh = umax(summary->in_flight / 2, 2);
+		call->cong_cwnd = call->cong_ssthresh + 3;
 		call->cong_extra = 0;
 		call->cong_dup_acks = 0;
-		resend = true;
+		summary->need_retransmit = true;
+		summary->in_fast_or_rto_recovery = true;
 		goto out;
 
-	case RXRPC_CALL_FAST_RETRANSMIT:
-		if (!summary->new_low_nack) {
-			if (summary->nr_new_acks == 0)
-				cwnd += 1;
+	case RXRPC_CA_FAST_RETRANSMIT:
+		rxrpc_tlp_init(call);
+		summary->in_fast_or_rto_recovery = true;
+		if (!summary->new_low_snack) {
+			if (summary->nr_new_sacks == 0)
+				call->cong_cwnd += 1;
 			call->cong_dup_acks++;
 			if (call->cong_dup_acks == 2) {
-				change = rxrpc_cong_retransmit_again;
+				summary->change = rxrpc_cong_retransmit_again;
 				call->cong_dup_acks = 0;
-				resend = true;
+				summary->need_retransmit = true;
 			}
 		} else {
-			change = rxrpc_cong_progress;
-			cwnd = call->cong_ssthresh;
-			if (summary->nr_nacks == 0)
+			summary->change = rxrpc_cong_progress;
+			call->cong_cwnd = call->cong_ssthresh;
+			if (call->acks_nr_snacks == 0) {
+				summary->exiting_fast_or_rto_recovery = true;
 				goto resume_normality;
+			}
 		}
 		goto out;
 
@@ -157,29 +137,25 @@ static void rxrpc_congestion_management(struct rxrpc_call *call,
 	}
 
 resume_normality:
-	change = rxrpc_cong_cleared_nacks;
+	summary->change = rxrpc_cong_cleared_nacks;
 	call->cong_dup_acks = 0;
 	call->cong_extra = 0;
-	call->cong_tstamp = skb->tstamp;
-	if (cwnd < call->cong_ssthresh)
-		call->cong_mode = RXRPC_CALL_SLOW_START;
+	call->cong_tstamp = call->acks_latest_ts;
+	if (call->cong_cwnd < call->cong_ssthresh)
+		call->cong_ca_state = RXRPC_CA_SLOW_START;
 	else
-		call->cong_mode = RXRPC_CALL_CONGEST_AVOIDANCE;
+		call->cong_ca_state = RXRPC_CA_CONGEST_AVOIDANCE;
 out:
-	cumulative_acks = 0;
+	call->cong_cumul_acks = 0;
 out_no_clear_ca:
-	if (cwnd >= RXRPC_RXTX_BUFF_SIZE - 1)
-		cwnd = RXRPC_RXTX_BUFF_SIZE - 1;
-	call->cong_cwnd = cwnd;
-	call->cong_cumul_acks = cumulative_acks;
-	trace_rxrpc_congest(call, summary, acked_serial, change);
-	if (resend && !test_and_set_bit(RXRPC_CALL_EV_RESEND, &call->events))
-		rxrpc_queue_call(call);
+	if (call->cong_cwnd >= RXRPC_TX_MAX_WINDOW)
+		call->cong_cwnd = RXRPC_TX_MAX_WINDOW;
+	trace_rxrpc_congest(call, summary);
 	return;
 
 packet_loss_detected:
-	change = rxrpc_cong_saw_nack;
-	call->cong_mode = RXRPC_CALL_PACKET_LOSS;
+	summary->change = rxrpc_cong_saw_nack;
+	call->cong_ca_state = RXRPC_CA_PACKET_LOSS;
 	call->cong_dup_acks = 0;
 	goto send_extra_data;
 
@@ -187,9 +163,8 @@ send_extra_data:
 	/* Send some previously unsent DATA if we have some to advance the ACK
 	 * state.
 	 */
-	if (call->rxtx_annotations[call->tx_top & RXRPC_RXTX_BUFF_MASK] &
-	    RXRPC_TX_ANNO_LAST ||
-	    summary->nr_acks != call->tx_top - call->tx_hard_ack) {
+	if (test_bit(RXRPC_CALL_TX_LAST, &call->flags) ||
+	    call->acks_nr_sacks != call->tx_top - call->tx_bottom) {
 		call->cong_extra++;
 		wake_up(&call->waitq);
 	}
@@ -197,71 +172,170 @@ send_extra_data:
 }
 
 /*
- * Ping the other end to fill our RTT cache and to retrieve the rwind
- * and MTU parameters.
+ * Degrade the congestion window if we haven't transmitted a packet for >1RTT.
  */
-static void rxrpc_send_ping(struct rxrpc_call *call, struct sk_buff *skb,
-			    int skew)
+void rxrpc_congestion_degrade(struct rxrpc_call *call)
 {
-	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
-	ktime_t now = skb->tstamp;
+	ktime_t rtt, now, time_since;
 
-	if (call->peer->rtt_usage < 3 ||
-	    ktime_before(ktime_add_ms(call->peer->rtt_last_req, 1000), now))
-		rxrpc_propose_ACK(call, RXRPC_ACK_PING, skew, sp->hdr.serial,
-				  true, true,
-				  rxrpc_propose_ack_ping_for_params);
+	if (call->cong_ca_state != RXRPC_CA_SLOW_START &&
+	    call->cong_ca_state != RXRPC_CA_CONGEST_AVOIDANCE)
+		return;
+	if (__rxrpc_call_state(call) == RXRPC_CALL_CLIENT_AWAIT_REPLY)
+		return;
+
+	rtt = ns_to_ktime(call->srtt_us * (NSEC_PER_USEC / 8));
+	now = ktime_get_real();
+	time_since = ktime_sub(now, call->tx_last_sent);
+	if (ktime_before(time_since, rtt))
+		return;
+
+	trace_rxrpc_reset_cwnd(call, time_since, rtt);
+	rxrpc_inc_stat(call->rxnet, stat_tx_data_cwnd_reset);
+	call->tx_last_sent = now;
+	call->cong_ca_state = RXRPC_CA_SLOW_START;
+	call->cong_ssthresh = umax(call->cong_ssthresh, call->cong_cwnd * 3 / 4);
+	call->cong_cwnd = umax(call->cong_cwnd / 2, RXRPC_MIN_CWND);
+}
+
+/*
+ * Add an RTT sample derived from an ACK'd DATA packet.
+ */
+static void rxrpc_add_data_rtt_sample(struct rxrpc_call *call,
+				      struct rxrpc_ack_summary *summary,
+				      struct rxrpc_txqueue *tq,
+				      int ix)
+{
+	ktime_t xmit_ts = ktime_add_us(tq->xmit_ts_base, tq->segment_xmit_ts[ix]);
+
+	rxrpc_call_add_rtt(call, rxrpc_rtt_rx_data_ack, -1,
+			   summary->acked_serial, summary->ack_serial,
+			   xmit_ts, call->acks_latest_ts);
+	__clear_bit(ix, &tq->rtt_samples); /* Prevent repeat RTT sample */
 }
 
 /*
  * Apply a hard ACK by advancing the Tx window.
  */
-static void rxrpc_rotate_tx_window(struct rxrpc_call *call, rxrpc_seq_t to,
+static bool rxrpc_rotate_tx_window(struct rxrpc_call *call, rxrpc_seq_t to,
 				   struct rxrpc_ack_summary *summary)
 {
-	struct sk_buff *skb, *list = NULL;
-	int ix;
-	u8 annotation;
+	struct rxrpc_txqueue *tq = call->tx_queue;
+	rxrpc_seq_t seq = call->tx_bottom + 1;
+	bool rot_last = false, trace = false;
+
+	_enter("%x,%x", call->tx_bottom, to);
 
-	if (call->acks_lowest_nak == call->tx_hard_ack) {
+	trace_rxrpc_tx_rotate(call, seq, to);
+	trace_rxrpc_tq(call, tq, seq, rxrpc_tq_rotate);
+
+	if (call->acks_lowest_nak == call->tx_bottom) {
 		call->acks_lowest_nak = to;
-	} else if (before_eq(call->acks_lowest_nak, to)) {
-		summary->new_low_nack = true;
+	} else if (after(to, call->acks_lowest_nak)) {
+		summary->new_low_snack = true;
 		call->acks_lowest_nak = to;
 	}
 
-	spin_lock(&call->lock);
+	/* We may have a left over fully-consumed buffer at the front that we
+	 * couldn't drop before (rotate_and_keep below).
+	 */
+	if (seq == call->tx_qbase + RXRPC_NR_TXQUEUE) {
+		call->tx_qbase += RXRPC_NR_TXQUEUE;
+		call->tx_queue = tq->next;
+		trace_rxrpc_tq(call, tq, seq, rxrpc_tq_rotate_and_free);
+		kfree(tq);
+		tq = call->tx_queue;
+	}
 
-	while (before(call->tx_hard_ack, to)) {
-		call->tx_hard_ack++;
-		ix = call->tx_hard_ack & RXRPC_RXTX_BUFF_MASK;
-		skb = call->rxtx_buffer[ix];
-		annotation = call->rxtx_annotations[ix];
-		rxrpc_see_skb(skb, rxrpc_skb_tx_rotated);
-		call->rxtx_buffer[ix] = NULL;
-		call->rxtx_annotations[ix] = 0;
-		skb->next = list;
-		list = skb;
+	do {
+		unsigned int ix = seq - call->tx_qbase;
 
-		if (annotation & RXRPC_TX_ANNO_LAST)
+		_debug("tq=%x seq=%x i=%d f=%x", tq->qbase, seq, ix, tq->bufs[ix]->flags);
+		if (tq->bufs[ix]->flags & RXRPC_LAST_PACKET) {
 			set_bit(RXRPC_CALL_TX_LAST, &call->flags);
-		if ((annotation & RXRPC_TX_ANNO_MASK) != RXRPC_TX_ANNO_ACK)
-			summary->nr_rot_new_acks++;
-	}
+			rot_last = true;
+		}
+
+		if (summary->acked_serial == tq->segment_serial[ix] &&
+		    test_bit(ix, &tq->rtt_samples))
+			rxrpc_add_data_rtt_sample(call, summary, tq, ix);
+
+		if (ix == tq->nr_reported_acks) {
+			/* Packet directly hard ACK'd. */
+			tq->nr_reported_acks++;
+			rxrpc_input_rack_one(call, summary, tq, ix);
+			if (seq == call->tlp_seq)
+				summary->tlp_probe_acked = true;
+			summary->nr_new_hacks++;
+			__set_bit(ix, &tq->segment_acked);
+			trace_rxrpc_rotate(call, tq, summary, seq, rxrpc_rotate_trace_hack);
+		} else if (test_bit(ix, &tq->segment_acked)) {
+			/* Soft ACK -> hard ACK. */
+			call->acks_nr_sacks--;
+			trace_rxrpc_rotate(call, tq, summary, seq, rxrpc_rotate_trace_sack);
+		} else {
+			/* Soft NAK -> hard ACK. */
+			call->acks_nr_snacks--;
+			rxrpc_input_rack_one(call, summary, tq, ix);
+			if (seq == call->tlp_seq)
+				summary->tlp_probe_acked = true;
+			summary->nr_new_hacks++;
+			__set_bit(ix, &tq->segment_acked);
+			trace_rxrpc_rotate(call, tq, summary, seq, rxrpc_rotate_trace_snak);
+		}
 
-	spin_unlock(&call->lock);
+		call->tx_nr_sent--;
+		if (__test_and_clear_bit(ix, &tq->segment_lost))
+			call->tx_nr_lost--;
+		if (__test_and_clear_bit(ix, &tq->segment_retransmitted))
+			call->tx_nr_resent--;
+		__clear_bit(ix, &tq->ever_retransmitted);
 
-	trace_rxrpc_transmit(call, (test_bit(RXRPC_CALL_TX_LAST, &call->flags) ?
-				    rxrpc_transmit_rotate_last :
-				    rxrpc_transmit_rotate));
-	wake_up(&call->waitq);
+		rxrpc_put_txbuf(tq->bufs[ix], rxrpc_txbuf_put_rotated);
+		tq->bufs[ix] = NULL;
+
+		WRITE_ONCE(call->tx_bottom, seq);
+		trace_rxrpc_txqueue(call, (rot_last ?
+					   rxrpc_txqueue_rotate_last :
+					   rxrpc_txqueue_rotate));
+
+		seq++;
+		trace = true;
+		if (!(seq & RXRPC_TXQ_MASK)) {
+			trace_rxrpc_rack_update(call, summary);
+			trace = false;
+			prefetch(tq->next);
+			if (tq != call->tx_qtail) {
+				call->tx_qbase += RXRPC_NR_TXQUEUE;
+				call->tx_queue = tq->next;
+				trace_rxrpc_tq(call, tq, seq, rxrpc_tq_rotate_and_free);
+				kfree(tq);
+				tq = call->tx_queue;
+			} else {
+				trace_rxrpc_tq(call, tq, seq, rxrpc_tq_rotate_and_keep);
+				tq = NULL;
+				break;
+			}
+		}
+
+	} while (before_eq(seq, to));
+
+	if (trace)
+		trace_rxrpc_rack_update(call, summary);
 
-	while (list) {
-		skb = list;
-		list = skb->next;
-		skb->next = NULL;
-		rxrpc_free_skb(skb, rxrpc_skb_tx_freed);
+	if (rot_last) {
+		set_bit(RXRPC_CALL_TX_ALL_ACKED, &call->flags);
+		if (tq) {
+			trace_rxrpc_tq(call, tq, seq, rxrpc_tq_rotate_and_free);
+			kfree(tq);
+			call->tx_queue = NULL;
+		}
 	}
+
+	_debug("%x,%x,%x,%d", to, call->tx_bottom, call->tx_top, rot_last);
+
+	wake_up(&call->waitq);
+	return rot_last;
 }
 
 /*
@@ -270,48 +344,39 @@ static void rxrpc_rotate_tx_window(struct rxrpc_call *call, rxrpc_seq_t to,
  * This occurs when we get an ACKALL packet, the first DATA packet of a reply,
  * or a final ACK packet.
  */
-static bool rxrpc_end_tx_phase(struct rxrpc_call *call, bool reply_begun,
-			       const char *abort_why)
+static void rxrpc_end_tx_phase(struct rxrpc_call *call, bool reply_begun,
+			       enum rxrpc_abort_reason abort_why)
 {
-
 	ASSERT(test_bit(RXRPC_CALL_TX_LAST, &call->flags));
 
-	write_lock(&call->state_lock);
+	call->rack_timer_mode = RXRPC_CALL_RACKTIMER_OFF;
+	call->rack_timo_at = KTIME_MAX;
+	trace_rxrpc_rack_timer(call, 0, false);
+	trace_rxrpc_timer_can(call, rxrpc_timer_trace_rack_off + call->rack_timer_mode);
 
-	switch (call->state) {
+	switch (__rxrpc_call_state(call)) {
 	case RXRPC_CALL_CLIENT_SEND_REQUEST:
 	case RXRPC_CALL_CLIENT_AWAIT_REPLY:
-		if (reply_begun)
-			call->state = RXRPC_CALL_CLIENT_RECV_REPLY;
-		else
-			call->state = RXRPC_CALL_CLIENT_AWAIT_REPLY;
+		if (reply_begun) {
+			rxrpc_set_call_state(call, RXRPC_CALL_CLIENT_RECV_REPLY);
+			trace_rxrpc_txqueue(call, rxrpc_txqueue_end);
+			break;
+		}
+
+		rxrpc_set_call_state(call, RXRPC_CALL_CLIENT_AWAIT_REPLY);
+		trace_rxrpc_txqueue(call, rxrpc_txqueue_await_reply);
 		break;
 
 	case RXRPC_CALL_SERVER_AWAIT_ACK:
-		__rxrpc_call_completed(call);
-		rxrpc_notify_socket(call);
+		rxrpc_call_completed(call);
+		trace_rxrpc_txqueue(call, rxrpc_txqueue_end);
 		break;
 
 	default:
-		goto bad_state;
-	}
-
-	write_unlock(&call->state_lock);
-	if (call->state == RXRPC_CALL_CLIENT_AWAIT_REPLY) {
-		rxrpc_propose_ACK(call, RXRPC_ACK_IDLE, 0, 0, false, true,
-				  rxrpc_propose_ack_client_tx_end);
-		trace_rxrpc_transmit(call, rxrpc_transmit_await_reply);
-	} else {
-		trace_rxrpc_transmit(call, rxrpc_transmit_end);
+		kdebug("end_tx %s", rxrpc_call_states[__rxrpc_call_state(call)]);
+		rxrpc_proto_abort(call, call->tx_top, abort_why);
+		break;
 	}
-	_leave(" = ok");
-	return true;
-
-bad_state:
-	write_unlock(&call->state_lock);
-	kdebug("end_tx %s", rxrpc_call_states[call->state]);
-	rxrpc_proto_abort(abort_why, call, call->tx_top);
-	return false;
 }
 
 /*
@@ -323,371 +388,565 @@ static bool rxrpc_receiving_reply(struct rxrpc_call *call)
 	rxrpc_seq_t top = READ_ONCE(call->tx_top);
 
 	if (call->ackr_reason) {
-		spin_lock_bh(&call->lock);
-		call->ackr_reason = 0;
-		call->resend_at = call->expire_at;
-		call->ack_at = call->expire_at;
-		spin_unlock_bh(&call->lock);
-		rxrpc_set_timer(call, rxrpc_timer_init_for_reply,
-				ktime_get_real());
+		call->delay_ack_at = KTIME_MAX;
+		trace_rxrpc_timer_can(call, rxrpc_timer_trace_delayed_ack);
 	}
 
-	if (!test_bit(RXRPC_CALL_TX_LAST, &call->flags))
-		rxrpc_rotate_tx_window(call, top, &summary);
 	if (!test_bit(RXRPC_CALL_TX_LAST, &call->flags)) {
-		rxrpc_proto_abort("TXL", call, top);
-		return false;
+		if (!rxrpc_rotate_tx_window(call, top, &summary)) {
+			rxrpc_proto_abort(call, top, rxrpc_eproto_early_reply);
+			return false;
+		}
 	}
-	if (!rxrpc_end_tx_phase(call, true, "ETD"))
-		return false;
-	call->tx_phase = false;
+
+	rxrpc_end_tx_phase(call, true, rxrpc_eproto_unexpected_reply);
 	return true;
 }
 
 /*
- * Scan a jumbo packet to validate its structure and to work out how many
- * subpackets it contains.
- *
- * A jumbo packet is a collection of consecutive packets glued together with
- * little headers between that indicate how to change the initial header for
- * each subpacket.
- *
- * RXRPC_JUMBO_PACKET must be set on all but the last subpacket - and all but
- * the last are RXRPC_JUMBO_DATALEN in size.  The last subpacket may be of any
- * size.
+ * End the packet reception phase.
  */
-static bool rxrpc_validate_jumbo(struct sk_buff *skb)
+static void rxrpc_end_rx_phase(struct rxrpc_call *call, rxrpc_serial_t serial)
 {
-	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
-	unsigned int offset = sizeof(struct rxrpc_wire_header);
-	unsigned int len = skb->len;
-	int nr_jumbo = 1;
-	u8 flags = sp->hdr.flags;
+	rxrpc_seq_t whigh = READ_ONCE(call->rx_highest_seq);
 
-	do {
-		nr_jumbo++;
-		if (len - offset < RXRPC_JUMBO_SUBPKTLEN)
-			goto protocol_error;
-		if (flags & RXRPC_LAST_PACKET)
-			goto protocol_error;
-		offset += RXRPC_JUMBO_DATALEN;
-		if (skb_copy_bits(skb, offset, &flags, 1) < 0)
-			goto protocol_error;
-		offset += sizeof(struct rxrpc_jumbo_header);
-	} while (flags & RXRPC_JUMBO_PACKET);
+	_enter("%d,%s", call->debug_id, rxrpc_call_states[__rxrpc_call_state(call)]);
 
-	sp->nr_jumbo = nr_jumbo;
-	return true;
+	trace_rxrpc_receive(call, rxrpc_receive_end, 0, whigh);
 
-protocol_error:
-	return false;
+	switch (__rxrpc_call_state(call)) {
+	case RXRPC_CALL_CLIENT_RECV_REPLY:
+		rxrpc_propose_delay_ACK(call, serial, rxrpc_propose_ack_terminal_ack);
+		rxrpc_call_completed(call);
+		break;
+
+	case RXRPC_CALL_SERVER_RECV_REQUEST:
+		rxrpc_set_call_state(call, RXRPC_CALL_SERVER_ACK_REQUEST);
+		call->expect_req_by = KTIME_MAX;
+		rxrpc_propose_delay_ACK(call, serial, rxrpc_propose_ack_processing_op);
+		break;
+
+	default:
+		break;
+	}
+}
+
+static void rxrpc_input_update_ack_window(struct rxrpc_call *call,
+					  rxrpc_seq_t window, rxrpc_seq_t wtop)
+{
+	call->ackr_window = window;
+	call->ackr_wtop = wtop;
 }
 
 /*
- * Handle reception of a duplicate packet.
- *
- * We have to take care to avoid an attack here whereby we're given a series of
- * jumbograms, each with a sequence number one before the preceding one and
- * filled up to maximum UDP size.  If they never send us the first packet in
- * the sequence, they can cause us to have to hold on to around 2MiB of kernel
- * space until the call times out.
- *
- * We limit the space usage by only accepting three duplicate jumbo packets per
- * call.  After that, we tell the other side we're no longer accepting jumbos
- * (that information is encoded in the ACK packet).
+ * Push a DATA packet onto the Rx queue.
  */
-static void rxrpc_input_dup_data(struct rxrpc_call *call, rxrpc_seq_t seq,
-				 u8 annotation, bool *_jumbo_bad)
+static void rxrpc_input_queue_data(struct rxrpc_call *call, struct sk_buff *skb,
+				   rxrpc_seq_t window, rxrpc_seq_t wtop,
+				   enum rxrpc_receive_trace why)
 {
-	/* Discard normal packets that are duplicates. */
-	if (annotation == 0)
-		return;
+	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
+	bool last = sp->hdr.flags & RXRPC_LAST_PACKET;
 
-	/* Skip jumbo subpackets that are duplicates.  When we've had three or
-	 * more partially duplicate jumbo packets, we refuse to take any more
-	 * jumbos for this call.
-	 */
-	if (!*_jumbo_bad) {
-		call->nr_jumbo_bad++;
-		*_jumbo_bad = true;
-	}
+	spin_lock_irq(&call->recvmsg_queue.lock);
+
+	__skb_queue_tail(&call->recvmsg_queue, skb);
+	rxrpc_input_update_ack_window(call, window, wtop);
+	trace_rxrpc_receive(call, last ? why + 1 : why, sp->hdr.serial, sp->hdr.seq);
+	if (last)
+		/* Change the state inside the lock so that recvmsg syncs
+		 * correctly with it and using sendmsg() to send a reply
+		 * doesn't race.
+		 */
+		rxrpc_end_rx_phase(call, sp->hdr.serial);
+
+	spin_unlock_irq(&call->recvmsg_queue.lock);
 }
 
 /*
- * Process a DATA packet, adding the packet to the Rx ring.
+ * Process a DATA packet.
  */
-static void rxrpc_input_data(struct rxrpc_call *call, struct sk_buff *skb,
-			     u16 skew)
+static void rxrpc_input_data_one(struct rxrpc_call *call, struct sk_buff *skb,
+				 bool *_notify, rxrpc_serial_t *_ack_serial, int *_ack_reason)
 {
 	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
-	enum rxrpc_call_state state;
-	unsigned int offset = sizeof(struct rxrpc_wire_header);
-	unsigned int ix;
-	rxrpc_serial_t serial = sp->hdr.serial, ack_serial = 0;
-	rxrpc_seq_t seq = sp->hdr.seq, hard_ack;
-	bool immediate_ack = false, jumbo_bad = false, queued;
-	u16 len;
-	u8 ack = 0, flags, annotation = 0;
+	struct sk_buff *oos;
+	rxrpc_serial_t serial = sp->hdr.serial;
+	unsigned int sack = call->ackr_sack_base;
+	rxrpc_seq_t window = call->ackr_window;
+	rxrpc_seq_t wtop = call->ackr_wtop;
+	rxrpc_seq_t wlimit = window + call->rx_winsize - 1;
+	rxrpc_seq_t seq = sp->hdr.seq;
+	bool last = sp->hdr.flags & RXRPC_LAST_PACKET;
+	int ack_reason = -1;
+
+	rxrpc_inc_stat(call->rxnet, stat_rx_data);
+	if (sp->hdr.flags & RXRPC_REQUEST_ACK)
+		rxrpc_inc_stat(call->rxnet, stat_rx_data_reqack);
+	if (sp->hdr.flags & RXRPC_JUMBO_PACKET)
+		rxrpc_inc_stat(call->rxnet, stat_rx_data_jumbo);
+
+	if (last) {
+		if (test_and_set_bit(RXRPC_CALL_RX_LAST, &call->flags) &&
+		    seq + 1 != wtop)
+			return rxrpc_proto_abort(call, seq, rxrpc_eproto_different_last);
+	} else {
+		if (test_bit(RXRPC_CALL_RX_LAST, &call->flags) &&
+		    after_eq(seq, wtop)) {
+			pr_warn("Packet beyond last: c=%x q=%x window=%x-%x wlimit=%x\n",
+				call->debug_id, seq, window, wtop, wlimit);
+			return rxrpc_proto_abort(call, seq, rxrpc_eproto_data_after_last);
+		}
+	}
 
-	_enter("{%u,%u},{%u,%u}",
-	       call->rx_hard_ack, call->rx_top, skb->len, seq);
+	if (after(seq, call->rx_highest_seq))
+		call->rx_highest_seq = seq;
 
-	_proto("Rx DATA %%%u { #%u f=%02x }",
-	       sp->hdr.serial, seq, sp->hdr.flags);
+	trace_rxrpc_rx_data(call->debug_id, seq, serial, sp->hdr.flags);
 
-	state = READ_ONCE(call->state);
-	if (state >= RXRPC_CALL_COMPLETE)
-		return;
+	if (before(seq, window)) {
+		ack_reason = RXRPC_ACK_DUPLICATE;
+		goto send_ack;
+	}
+	if (after(seq, wlimit)) {
+		ack_reason = RXRPC_ACK_EXCEEDS_WINDOW;
+		goto send_ack;
+	}
 
-	/* Received data implicitly ACKs all of the request packets we sent
-	 * when we're acting as a client.
-	 */
-	if ((state == RXRPC_CALL_CLIENT_SEND_REQUEST ||
-	     state == RXRPC_CALL_CLIENT_AWAIT_REPLY) &&
-	    !rxrpc_receiving_reply(call))
-		return;
+	/* Queue the packet. */
+	if (seq == window) {
+		if (sp->hdr.flags & RXRPC_REQUEST_ACK)
+			ack_reason = RXRPC_ACK_REQUESTED;
+		/* Send an immediate ACK if we fill in a hole */
+		else if (!skb_queue_empty(&call->rx_oos_queue))
+			ack_reason = RXRPC_ACK_DELAY;
 
-	call->ackr_prev_seq = seq;
+		window++;
+		if (after(window, wtop)) {
+			trace_rxrpc_sack(call, seq, sack, rxrpc_sack_none);
+			wtop = window;
+		} else {
+			trace_rxrpc_sack(call, seq, sack, rxrpc_sack_advance);
+			sack = (sack + 1) % RXRPC_SACK_SIZE;
+		}
 
-	hard_ack = READ_ONCE(call->rx_hard_ack);
-	if (after(seq, hard_ack + call->rx_winsize)) {
-		ack = RXRPC_ACK_EXCEEDS_WINDOW;
-		ack_serial = serial;
-		goto ack;
-	}
 
-	flags = sp->hdr.flags;
-	if (flags & RXRPC_JUMBO_PACKET) {
-		if (call->nr_jumbo_bad > 3) {
-			ack = RXRPC_ACK_NOSPACE;
-			ack_serial = serial;
-			goto ack;
-		}
-		annotation = 1;
-	}
+		rxrpc_get_skb(skb, rxrpc_skb_get_to_recvmsg);
 
-next_subpacket:
-	queued = false;
-	ix = seq & RXRPC_RXTX_BUFF_MASK;
-	len = skb->len;
-	if (flags & RXRPC_JUMBO_PACKET)
-		len = RXRPC_JUMBO_DATALEN;
+		rxrpc_input_queue_data(call, skb, window, wtop, rxrpc_receive_queue);
+		*_notify = true;
 
-	if (flags & RXRPC_LAST_PACKET) {
-		if (test_bit(RXRPC_CALL_RX_LAST, &call->flags) &&
-		    seq != call->rx_top)
-			return rxrpc_proto_abort("LSN", call, seq);
-	} else {
-		if (test_bit(RXRPC_CALL_RX_LAST, &call->flags) &&
-		    after_eq(seq, call->rx_top))
-			return rxrpc_proto_abort("LSA", call, seq);
-	}
+		while ((oos = skb_peek(&call->rx_oos_queue))) {
+			struct rxrpc_skb_priv *osp = rxrpc_skb(oos);
 
-	trace_rxrpc_rx_data(call, seq, serial, flags, annotation);
-	if (before_eq(seq, hard_ack)) {
-		ack = RXRPC_ACK_DUPLICATE;
-		ack_serial = serial;
-		goto skip;
-	}
+			if (after(osp->hdr.seq, window))
+				break;
 
-	if (flags & RXRPC_REQUEST_ACK && !ack) {
-		ack = RXRPC_ACK_REQUESTED;
-		ack_serial = serial;
-	}
+			__skb_unlink(oos, &call->rx_oos_queue);
+			last = osp->hdr.flags & RXRPC_LAST_PACKET;
+			seq = osp->hdr.seq;
+			call->ackr_sack_table[sack] = 0;
+			trace_rxrpc_sack(call, seq, sack, rxrpc_sack_fill);
+			sack = (sack + 1) % RXRPC_SACK_SIZE;
 
-	if (call->rxtx_buffer[ix]) {
-		rxrpc_input_dup_data(call, seq, annotation, &jumbo_bad);
-		if (ack != RXRPC_ACK_DUPLICATE) {
-			ack = RXRPC_ACK_DUPLICATE;
-			ack_serial = serial;
+			window++;
+			rxrpc_input_queue_data(call, oos, window, wtop,
+					       rxrpc_receive_queue_oos);
 		}
-		immediate_ack = true;
-		goto skip;
-	}
 
-	/* Queue the packet.  We use a couple of memory barriers here as need
-	 * to make sure that rx_top is perceived to be set after the buffer
-	 * pointer and that the buffer pointer is set after the annotation and
-	 * the skb data.
-	 *
-	 * Barriers against rxrpc_recvmsg_data() and rxrpc_rotate_rx_window()
-	 * and also rxrpc_fill_out_ack().
-	 */
-	rxrpc_get_skb(skb, rxrpc_skb_rx_got);
-	call->rxtx_annotations[ix] = annotation;
-	smp_wmb();
-	call->rxtx_buffer[ix] = skb;
-	if (after(seq, call->rx_top)) {
-		smp_store_release(&call->rx_top, seq);
-	} else if (before(seq, call->rx_top)) {
-		/* Send an immediate ACK if we fill in a hole */
-		if (!ack) {
-			ack = RXRPC_ACK_DELAY;
-			ack_serial = serial;
-		}
-		immediate_ack = true;
-	}
-	if (flags & RXRPC_LAST_PACKET) {
-		set_bit(RXRPC_CALL_RX_LAST, &call->flags);
-		trace_rxrpc_receive(call, rxrpc_receive_queue_last, serial, seq);
+		call->ackr_sack_base = sack;
 	} else {
-		trace_rxrpc_receive(call, rxrpc_receive_queue, serial, seq);
-	}
-	queued = true;
+		unsigned int slot;
+
+		ack_reason = RXRPC_ACK_OUT_OF_SEQUENCE;
+
+		slot = seq - window;
+		sack = (sack + slot) % RXRPC_SACK_SIZE;
 
-	if (after_eq(seq, call->rx_expect_next)) {
-		if (after(seq, call->rx_expect_next)) {
-			_net("OOS %u > %u", seq, call->rx_expect_next);
-			ack = RXRPC_ACK_OUT_OF_SEQUENCE;
-			ack_serial = serial;
+		if (call->ackr_sack_table[sack % RXRPC_SACK_SIZE]) {
+			ack_reason = RXRPC_ACK_DUPLICATE;
+			goto send_ack;
 		}
-		call->rx_expect_next = seq + 1;
-	}
 
-skip:
-	offset += len;
-	if (flags & RXRPC_JUMBO_PACKET) {
-		if (skb_copy_bits(skb, offset, &flags, 1) < 0)
-			return rxrpc_proto_abort("XJF", call, seq);
-		offset += sizeof(struct rxrpc_jumbo_header);
-		seq++;
-		serial++;
-		annotation++;
-		if (flags & RXRPC_JUMBO_PACKET)
-			annotation |= RXRPC_RX_ANNO_JLAST;
-		if (after(seq, hard_ack + call->rx_winsize)) {
-			ack = RXRPC_ACK_EXCEEDS_WINDOW;
-			ack_serial = serial;
-			if (!jumbo_bad) {
-				call->nr_jumbo_bad++;
-				jumbo_bad = true;
+		call->ackr_sack_table[sack % RXRPC_SACK_SIZE] |= 1;
+		trace_rxrpc_sack(call, seq, sack, rxrpc_sack_oos);
+
+		if (after(seq + 1, wtop)) {
+			wtop = seq + 1;
+			rxrpc_input_update_ack_window(call, window, wtop);
+		}
+
+		skb_queue_walk(&call->rx_oos_queue, oos) {
+			struct rxrpc_skb_priv *osp = rxrpc_skb(oos);
+
+			if (after(osp->hdr.seq, seq)) {
+				rxrpc_get_skb(skb, rxrpc_skb_get_to_recvmsg_oos);
+				__skb_queue_before(&call->rx_oos_queue, oos, skb);
+				goto oos_queued;
 			}
-			goto ack;
 		}
 
-		_proto("Rx DATA Jumbo %%%u", serial);
-		goto next_subpacket;
+		rxrpc_get_skb(skb, rxrpc_skb_get_to_recvmsg_oos);
+		__skb_queue_tail(&call->rx_oos_queue, skb);
+	oos_queued:
+		trace_rxrpc_receive(call, last ? rxrpc_receive_oos_last : rxrpc_receive_oos,
+				    sp->hdr.serial, sp->hdr.seq);
 	}
 
-	if (queued && flags & RXRPC_LAST_PACKET && !ack) {
-		ack = RXRPC_ACK_DELAY;
-		ack_serial = serial;
+send_ack:
+	if (ack_reason >= 0) {
+		if (rxrpc_ack_priority[ack_reason] > rxrpc_ack_priority[*_ack_reason]) {
+			*_ack_serial = serial;
+			*_ack_reason = ack_reason;
+		} else if (rxrpc_ack_priority[ack_reason] == rxrpc_ack_priority[*_ack_reason] &&
+			   ack_reason == RXRPC_ACK_REQUESTED) {
+			*_ack_serial = serial;
+			*_ack_reason = ack_reason;
+		}
+	}
+}
+
+/*
+ * Split a jumbo packet and file the bits separately.
+ */
+static bool rxrpc_input_split_jumbo(struct rxrpc_call *call, struct sk_buff *skb)
+{
+	struct rxrpc_jumbo_header jhdr;
+	struct rxrpc_skb_priv *sp = rxrpc_skb(skb), *jsp;
+	struct sk_buff *jskb;
+	rxrpc_serial_t ack_serial = 0;
+	unsigned int offset = sizeof(struct rxrpc_wire_header);
+	unsigned int len = skb->len - offset;
+	bool notify = false;
+	int ack_reason = 0, count = 1, stat_ix;
+
+	while (sp->hdr.flags & RXRPC_JUMBO_PACKET) {
+		if (len < RXRPC_JUMBO_SUBPKTLEN)
+			goto protocol_error;
+		if (sp->hdr.flags & RXRPC_LAST_PACKET)
+			goto protocol_error;
+		if (skb_copy_bits(skb, offset + RXRPC_JUMBO_DATALEN,
+				  &jhdr, sizeof(jhdr)) < 0)
+			goto protocol_error;
+
+		jskb = skb_clone(skb, GFP_NOFS);
+		if (!jskb) {
+			kdebug("couldn't clone");
+			return false;
+		}
+		rxrpc_new_skb(jskb, rxrpc_skb_new_jumbo_subpacket);
+		jsp = rxrpc_skb(jskb);
+		jsp->offset = offset;
+		jsp->len = RXRPC_JUMBO_DATALEN;
+		rxrpc_input_data_one(call, jskb, &notify, &ack_serial, &ack_reason);
+		rxrpc_free_skb(jskb, rxrpc_skb_put_jumbo_subpacket);
+
+		sp->hdr.flags = jhdr.flags;
+		sp->hdr._rsvd = ntohs(jhdr._rsvd);
+		sp->hdr.seq++;
+		sp->hdr.serial++;
+		offset += RXRPC_JUMBO_SUBPKTLEN;
+		len -= RXRPC_JUMBO_SUBPKTLEN;
+		count++;
 	}
 
-ack:
-	if (ack)
-		rxrpc_propose_ACK(call, ack, skew, ack_serial,
-				  immediate_ack, true,
-				  rxrpc_propose_ack_input_data);
+	sp->offset = offset;
+	sp->len    = len;
+	rxrpc_input_data_one(call, skb, &notify, &ack_serial, &ack_reason);
 
-	if (sp->hdr.seq == READ_ONCE(call->rx_hard_ack) + 1)
+	stat_ix = umin(count, ARRAY_SIZE(call->rxnet->stat_rx_jumbo)) - 1;
+	atomic_inc(&call->rxnet->stat_rx_jumbo[stat_ix]);
+
+	if (ack_reason > 0) {
+		rxrpc_send_ACK(call, ack_reason, ack_serial,
+			       rxrpc_propose_ack_input_data);
+	} else {
+		call->ackr_nr_unacked++;
+		rxrpc_propose_delay_ACK(call, sp->hdr.serial,
+					rxrpc_propose_ack_input_data);
+	}
+	if (notify && !test_bit(RXRPC_CALL_CONN_CHALLENGING, &call->flags)) {
+		trace_rxrpc_notify_socket(call->debug_id, sp->hdr.serial);
 		rxrpc_notify_socket(call);
-	_leave(" [queued]");
+	}
+	return true;
+
+protocol_error:
+	return false;
 }
 
 /*
- * Process a requested ACK.
+ * Process a DATA packet, adding the packet to the Rx ring.  The caller's
+ * packet ref must be passed on or discarded.
  */
-static void rxrpc_input_requested_ack(struct rxrpc_call *call,
-				      ktime_t resp_time,
-				      rxrpc_serial_t orig_serial,
-				      rxrpc_serial_t ack_serial)
+static void rxrpc_input_data(struct rxrpc_call *call, struct sk_buff *skb)
 {
-	struct rxrpc_skb_priv *sp;
-	struct sk_buff *skb;
-	ktime_t sent_at;
-	int ix;
+	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
+	rxrpc_serial_t serial = sp->hdr.serial;
+	rxrpc_seq_t seq0 = sp->hdr.seq;
 
-	for (ix = 0; ix < RXRPC_RXTX_BUFF_SIZE; ix++) {
-		skb = call->rxtx_buffer[ix];
-		if (!skb)
-			continue;
+	_enter("{%x,%x,%x},{%u,%x}",
+	       call->ackr_window, call->ackr_wtop, call->rx_highest_seq,
+	       skb->len, seq0);
 
-		sp = rxrpc_skb(skb);
-		if (sp->hdr.serial != orig_serial)
-			continue;
-		smp_rmb();
-		sent_at = skb->tstamp;
-		goto found;
+	if (__rxrpc_call_is_complete(call))
+		return;
+
+	switch (__rxrpc_call_state(call)) {
+	case RXRPC_CALL_CLIENT_SEND_REQUEST:
+	case RXRPC_CALL_CLIENT_AWAIT_REPLY:
+		/* Received data implicitly ACKs all of the request
+		 * packets we sent when we're acting as a client.
+		 */
+		if (!rxrpc_receiving_reply(call))
+			goto out_notify;
+		break;
+
+	case RXRPC_CALL_SERVER_RECV_REQUEST: {
+		unsigned long timo = READ_ONCE(call->next_req_timo);
+
+		if (timo) {
+			ktime_t delay = ms_to_ktime(timo);
+
+			call->expect_req_by = ktime_add(ktime_get_real(), delay);
+			trace_rxrpc_timer_set(call, delay, rxrpc_timer_trace_idle);
+		}
+		break;
+	}
+
+	default:
+		break;
+	}
+
+	if (!rxrpc_input_split_jumbo(call, skb)) {
+		rxrpc_proto_abort(call, sp->hdr.seq, rxrpc_badmsg_bad_jumbo);
+		goto out_notify;
 	}
 	return;
 
-found:
-	rxrpc_peer_add_rtt(call, rxrpc_rtt_rx_requested_ack,
-			   orig_serial, ack_serial, sent_at, resp_time);
+out_notify:
+	trace_rxrpc_notify_socket(call->debug_id, serial);
+	rxrpc_notify_socket(call);
+	_leave(" [queued]");
 }
 
 /*
- * Process a ping response.
+ * See if there's a cached RTT probe to complete.
  */
-static void rxrpc_input_ping_response(struct rxrpc_call *call,
-				      ktime_t resp_time,
-				      rxrpc_serial_t orig_serial,
-				      rxrpc_serial_t ack_serial)
+static void rxrpc_complete_rtt_probe(struct rxrpc_call *call,
+				     ktime_t resp_time,
+				     rxrpc_serial_t acked_serial,
+				     rxrpc_serial_t ack_serial,
+				     enum rxrpc_rtt_rx_trace type)
 {
-	rxrpc_serial_t ping_serial;
-	ktime_t ping_time;
+	rxrpc_serial_t orig_serial;
+	unsigned long avail;
+	ktime_t sent_at;
+	bool matched = false;
+	int i;
 
-	ping_time = call->ping_time;
-	smp_rmb();
-	ping_serial = call->ping_serial;
+	avail = READ_ONCE(call->rtt_avail);
+	smp_rmb(); /* Read avail bits before accessing data. */
 
-	if (!test_bit(RXRPC_CALL_PINGING, &call->flags) ||
-	    before(orig_serial, ping_serial))
-		return;
-	clear_bit(RXRPC_CALL_PINGING, &call->flags);
-	if (after(orig_serial, ping_serial))
-		return;
+	for (i = 0; i < ARRAY_SIZE(call->rtt_serial); i++) {
+		if (!test_bit(i + RXRPC_CALL_RTT_PEND_SHIFT, &avail))
+			continue;
+
+		sent_at = call->rtt_sent_at[i];
+		orig_serial = call->rtt_serial[i];
 
-	rxrpc_peer_add_rtt(call, rxrpc_rtt_rx_ping_response,
-			   orig_serial, ack_serial, ping_time, resp_time);
+		if (orig_serial == acked_serial) {
+			clear_bit(i + RXRPC_CALL_RTT_PEND_SHIFT, &call->rtt_avail);
+			smp_mb(); /* Read data before setting avail bit */
+			set_bit(i, &call->rtt_avail);
+			rxrpc_call_add_rtt(call, type, i, acked_serial, ack_serial,
+					   sent_at, resp_time);
+			matched = true;
+		}
+
+		/* If a later serial is being acked, then mark this slot as
+		 * being available.
+		 */
+		if (after(acked_serial, orig_serial)) {
+			trace_rxrpc_rtt_rx(call, rxrpc_rtt_rx_obsolete, i,
+					   orig_serial, acked_serial, 0, 0, 0);
+			clear_bit(i + RXRPC_CALL_RTT_PEND_SHIFT, &call->rtt_avail);
+			smp_wmb();
+			set_bit(i, &call->rtt_avail);
+		}
+	}
+
+	if (!matched)
+		trace_rxrpc_rtt_rx(call, rxrpc_rtt_rx_lost, 9, 0, acked_serial, 0, 0, 0);
 }
 
 /*
  * Process the extra information that may be appended to an ACK packet
  */
-static void rxrpc_input_ackinfo(struct rxrpc_call *call, struct sk_buff *skb,
-				struct rxrpc_ackinfo *ackinfo)
+static void rxrpc_input_ack_trailer(struct rxrpc_call *call, struct sk_buff *skb,
+				    struct rxrpc_acktrailer *trailer)
 {
 	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
-	struct rxrpc_peer *peer;
-	unsigned int mtu;
+	struct rxrpc_peer *peer = call->peer;
+	unsigned int max_data, capacity;
 	bool wake = false;
-	u32 rwind = ntohl(ackinfo->rwind);
-
-	_proto("Rx ACK %%%u Info { rx=%u max=%u rwin=%u jm=%u }",
-	       sp->hdr.serial,
-	       ntohl(ackinfo->rxMTU), ntohl(ackinfo->maxMTU),
-	       rwind, ntohl(ackinfo->jumbo_max));
+	u32 max_mtu	= ntohl(trailer->maxMTU);
+	//u32 if_mtu	= ntohl(trailer->ifMTU);
+	u32 rwind	= ntohl(trailer->rwind);
+	u32 jumbo_max	= ntohl(trailer->jumbo_max);
 
+	if (rwind > RXRPC_TX_MAX_WINDOW)
+		rwind = RXRPC_TX_MAX_WINDOW;
 	if (call->tx_winsize != rwind) {
-		if (rwind > RXRPC_RXTX_BUFF_SIZE - 1)
-			rwind = RXRPC_RXTX_BUFF_SIZE - 1;
 		if (rwind > call->tx_winsize)
 			wake = true;
-		trace_rxrpc_rx_rwind_change(call, sp->hdr.serial,
-					    ntohl(ackinfo->rwind), wake);
+		trace_rxrpc_rx_rwind_change(call, sp->hdr.serial, rwind, wake);
 		call->tx_winsize = rwind;
 	}
 
-	if (call->cong_ssthresh > rwind)
-		call->cong_ssthresh = rwind;
+	max_mtu = clamp(max_mtu, 500, 65535);
+	peer->ackr_max_data = max_mtu;
 
-	mtu = min(ntohl(ackinfo->rxMTU), ntohl(ackinfo->maxMTU));
+	if (max_mtu < peer->max_data) {
+		trace_rxrpc_pmtud_reduce(peer, sp->hdr.serial, max_mtu,
+					 rxrpc_pmtud_reduce_ack);
+		peer->max_data = max_mtu;
+	}
 
-	peer = call->peer;
-	if (mtu < peer->maxdata) {
-		spin_lock_bh(&peer->lock);
-		peer->maxdata = mtu;
-		peer->mtu = mtu + peer->hdrsize;
-		spin_unlock_bh(&peer->lock);
-		_net("Net MTU %u (maxdata %u)", peer->mtu, peer->maxdata);
+	max_data = umin(max_mtu, peer->max_data);
+	capacity = max_data;
+	capacity += sizeof(struct rxrpc_jumbo_header); /* First subpacket has main hdr, not jumbo */
+	capacity /= sizeof(struct rxrpc_jumbo_header) + RXRPC_JUMBO_DATALEN;
+
+	if (jumbo_max == 0) {
+		/* The peer says it supports pmtu discovery */
+		peer->ackr_adv_pmtud = true;
+	} else {
+		peer->ackr_adv_pmtud = false;
+		capacity = clamp(capacity, 1, jumbo_max);
 	}
 
+	call->tx_jumbo_max = capacity;
+
 	if (wake)
 		wake_up(&call->waitq);
 }
 
+#if defined(CONFIG_X86) && __GNUC__ && !defined(__clang__)
+/* Clang doesn't support the %z constraint modifier */
+#define shiftr_adv_rotr(shift_from, rotate_into) ({			\
+			asm(" shr%z1 %1\n"				\
+			    " inc %0\n"					\
+			    " rcr%z2 %2\n"				\
+			    : "+d"(shift_from), "+m"(*(shift_from)), "+rm"(rotate_into) \
+			    );						\
+		})
+#else
+#define shiftr_adv_rotr(shift_from, rotate_into) ({	\
+			typeof(rotate_into) __bit0 = *(shift_from) & 1;	\
+			*(shift_from) >>= 1;				\
+			shift_from++;					\
+			rotate_into >>= 1;				\
+			rotate_into |= __bit0 << (sizeof(rotate_into) * 8 - 1); \
+		})
+#endif
+
+/*
+ * Deal with RTT samples from soft ACKs.
+ */
+static void rxrpc_input_soft_rtt(struct rxrpc_call *call,
+				 struct rxrpc_ack_summary *summary,
+				 struct rxrpc_txqueue *tq)
+{
+	for (int ix = 0; ix < RXRPC_NR_TXQUEUE; ix++)
+		if (summary->acked_serial == tq->segment_serial[ix])
+			return rxrpc_add_data_rtt_sample(call, summary, tq, ix);
+}
+
+/*
+ * Process a batch of soft ACKs specific to a transmission queue segment.
+ */
+static void rxrpc_input_soft_ack_tq(struct rxrpc_call *call,
+				    struct rxrpc_ack_summary *summary,
+				    struct rxrpc_txqueue *tq,
+				    unsigned long extracted_acks,
+				    int nr_reported,
+				    rxrpc_seq_t seq,
+				    rxrpc_seq_t *lowest_nak)
+{
+	unsigned long old_reported = 0, flipped, new_acks = 0;
+	unsigned long a_to_n, n_to_a = 0;
+	int new, a, n;
+
+	if (tq->nr_reported_acks > 0)
+		old_reported = ~0UL >> (RXRPC_NR_TXQUEUE - tq->nr_reported_acks);
+
+	_enter("{%x,%lx,%d},%lx,%d,%x",
+	       tq->qbase, tq->segment_acked, tq->nr_reported_acks,
+	       extracted_acks, nr_reported, seq);
+
+	_debug("[%x]", tq->qbase);
+	_debug("tq    %16lx %u", tq->segment_acked, tq->nr_reported_acks);
+	_debug("sack  %16lx %u", extracted_acks, nr_reported);
+
+	/* See how many previously logged ACKs/NAKs have flipped. */
+	flipped = (tq->segment_acked ^ extracted_acks) & old_reported;
+	if (flipped) {
+		n_to_a = ~tq->segment_acked & flipped; /* Old NAK -> ACK */
+		a_to_n =  tq->segment_acked & flipped; /* Old ACK -> NAK */
+		a = hweight_long(n_to_a);
+		n = hweight_long(a_to_n);
+		_debug("flip  %16lx", flipped);
+		_debug("ntoa  %16lx %d", n_to_a, a);
+		_debug("aton  %16lx %d", a_to_n, n);
+		call->acks_nr_sacks	+= a - n;
+		call->acks_nr_snacks	+= n - a;
+		summary->nr_new_sacks	+= a;
+		summary->nr_new_snacks	+= n;
+	}
+
+	/* See how many new ACKs/NAKs have been acquired. */
+	new = nr_reported - tq->nr_reported_acks;
+	if (new > 0) {
+		new_acks = extracted_acks & ~old_reported;
+		if (new_acks) {
+			a = hweight_long(new_acks);
+			n = new - a;
+			_debug("new_a %16lx new=%d a=%d n=%d", new_acks, new, a, n);
+			call->acks_nr_sacks	+= a;
+			call->acks_nr_snacks	+= n;
+			summary->nr_new_sacks	+= a;
+			summary->nr_new_snacks	+= n;
+		} else {
+			call->acks_nr_snacks	+= new;
+			summary->nr_new_snacks	+= new;
+		}
+	}
+
+	tq->nr_reported_acks = nr_reported;
+	tq->segment_acked = extracted_acks;
+	trace_rxrpc_apply_acks(call, tq);
+
+	if (extracted_acks != ~0UL) {
+		rxrpc_seq_t lowest = seq + ffz(extracted_acks);
+
+		if (before(lowest, *lowest_nak))
+			*lowest_nak = lowest;
+	}
+
+	if (summary->acked_serial)
+		rxrpc_input_soft_rtt(call, summary, tq);
+
+	new_acks |= n_to_a;
+	if (new_acks)
+		rxrpc_input_rack(call, summary, tq, new_acks);
+
+	if (call->tlp_serial &&
+	    rxrpc_seq_in_txq(tq, call->tlp_seq) &&
+	    test_bit(call->tlp_seq - tq->qbase, &new_acks))
+		summary->tlp_probe_acked = true;
+}
+
 /*
  * Process individual soft ACKs.
  *
@@ -697,46 +956,91 @@ static void rxrpc_input_ackinfo(struct rxrpc_call *call, struct sk_buff *skb,
  * the timer on the basis that the peer might just not have processed them at
  * the time the ACK was sent.
  */
-static void rxrpc_input_soft_acks(struct rxrpc_call *call, u8 *acks,
-				  rxrpc_seq_t seq, int nr_acks,
-				  struct rxrpc_ack_summary *summary)
+static void rxrpc_input_soft_acks(struct rxrpc_call *call,
+				  struct rxrpc_ack_summary *summary,
+				  struct sk_buff *skb)
 {
-	int ix;
-	u8 annotation, anno_type;
-
-	for (; nr_acks > 0; nr_acks--, seq++) {
-		ix = seq & RXRPC_RXTX_BUFF_MASK;
-		annotation = call->rxtx_annotations[ix];
-		anno_type = annotation & RXRPC_TX_ANNO_MASK;
-		annotation &= ~RXRPC_TX_ANNO_MASK;
-		switch (*acks++) {
-		case RXRPC_ACK_TYPE_ACK:
-			summary->nr_acks++;
-			if (anno_type == RXRPC_TX_ANNO_ACK)
-				continue;
-			summary->nr_new_acks++;
-			call->rxtx_annotations[ix] =
-				RXRPC_TX_ANNO_ACK | annotation;
-			break;
-		case RXRPC_ACK_TYPE_NACK:
-			if (!summary->nr_nacks &&
-			    call->acks_lowest_nak != seq) {
-				call->acks_lowest_nak = seq;
-				summary->new_low_nack = true;
-			}
-			summary->nr_nacks++;
-			if (anno_type == RXRPC_TX_ANNO_NAK)
-				continue;
-			summary->nr_new_nacks++;
-			if (anno_type == RXRPC_TX_ANNO_RETRANS)
-				continue;
-			call->rxtx_annotations[ix] =
-				RXRPC_TX_ANNO_NAK | annotation;
-			break;
-		default:
-			return rxrpc_proto_abort("SFT", call, 0);
+	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
+	struct rxrpc_txqueue *tq = call->tx_queue;
+	unsigned long extracted = ~0UL;
+	unsigned int nr = 0;
+	rxrpc_seq_t seq = call->acks_hard_ack + 1;
+	rxrpc_seq_t lowest_nak = seq + sp->ack.nr_acks;
+	u8 *acks = skb->data + sizeof(struct rxrpc_wire_header) + sizeof(struct rxrpc_ackpacket);
+
+	_enter("%x,%x,%u", tq->qbase, seq, sp->ack.nr_acks);
+
+	while (after(seq, tq->qbase + RXRPC_NR_TXQUEUE - 1))
+		tq = tq->next;
+
+	for (unsigned int i = 0; i < sp->ack.nr_acks; i++) {
+		/* Decant ACKs until we hit a txqueue boundary. */
+		shiftr_adv_rotr(acks, extracted);
+		if (i == 256) {
+			acks -= i;
+			i = 0;
 		}
+		seq++;
+		nr++;
+		if ((seq & RXRPC_TXQ_MASK) != 0)
+			continue;
+
+		_debug("bound %16lx %u", extracted, nr);
+
+		rxrpc_input_soft_ack_tq(call, summary, tq, extracted, RXRPC_NR_TXQUEUE,
+					seq - RXRPC_NR_TXQUEUE, &lowest_nak);
+		extracted = ~0UL;
+		nr = 0;
+		tq = tq->next;
+		prefetch(tq);
 	}
+
+	if (nr) {
+		unsigned int nr_reported = seq & RXRPC_TXQ_MASK;
+
+		extracted >>= RXRPC_NR_TXQUEUE - nr_reported;
+		_debug("tail  %16lx %u", extracted, nr_reported);
+		rxrpc_input_soft_ack_tq(call, summary, tq, extracted, nr_reported,
+					seq & ~RXRPC_TXQ_MASK, &lowest_nak);
+	}
+
+	/* We *can* have more nacks than we did - the peer is permitted to drop
+	 * packets it has soft-acked and re-request them.  Further, it is
+	 * possible for the nack distribution to change whilst the number of
+	 * nacks stays the same or goes down.
+	 */
+	if (lowest_nak != call->acks_lowest_nak) {
+		call->acks_lowest_nak = lowest_nak;
+		summary->new_low_snack = true;
+	}
+
+	_debug("summary A=%d+%d N=%d+%d",
+	       call->acks_nr_sacks,  summary->nr_new_sacks,
+	       call->acks_nr_snacks, summary->nr_new_snacks);
+}
+
+/*
+ * Return true if the ACK is valid - ie. it doesn't appear to have regressed
+ * with respect to the ack state conveyed by preceding ACKs.
+ */
+static bool rxrpc_is_ack_valid(struct rxrpc_call *call,
+			       rxrpc_seq_t hard_ack, rxrpc_seq_t prev_pkt)
+{
+	rxrpc_seq_t base = READ_ONCE(call->acks_hard_ack);
+
+	if (after(hard_ack, base))
+		return true; /* The window advanced */
+
+	if (before(hard_ack, base))
+		return false; /* firstPacket regressed */
+
+	if (after_eq(prev_pkt, call->acks_prev_seq))
+		return true; /* previousPacket hasn't regressed. */
+
+	/* Some rx implementations put a serial number in previousPacket. */
+	if (after(prev_pkt, base + call->tx_winsize))
+		return false;
+	return true;
 }
 
 /*
@@ -749,118 +1053,151 @@ static void rxrpc_input_soft_acks(struct rxrpc_call *call, u8 *acks,
  * soft-ACK means that the packet may be discarded and retransmission
  * requested.  A phase is complete when all packets are hard-ACK'd.
  */
-static void rxrpc_input_ack(struct rxrpc_call *call, struct sk_buff *skb,
-			    u16 skew)
+static void rxrpc_input_ack(struct rxrpc_call *call, struct sk_buff *skb)
 {
 	struct rxrpc_ack_summary summary = { 0 };
+	struct rxrpc_acktrailer trailer;
 	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
-	union {
-		struct rxrpc_ackpacket ack;
-		struct rxrpc_ackinfo info;
-		u8 acks[RXRPC_MAXACKS];
-	} buf;
-	rxrpc_serial_t acked_serial;
-	rxrpc_seq_t first_soft_ack, hard_ack;
+	rxrpc_seq_t first_soft_ack, hard_ack, prev_pkt;
 	int nr_acks, offset, ioffset;
 
 	_enter("");
 
-	offset = sizeof(struct rxrpc_wire_header);
-	if (skb_copy_bits(skb, offset, &buf.ack, sizeof(buf.ack)) < 0) {
-		_debug("extraction failure");
-		return rxrpc_proto_abort("XAK", call, 0);
+	offset = sizeof(struct rxrpc_wire_header) + sizeof(struct rxrpc_ackpacket);
+
+	summary.ack_serial	= sp->hdr.serial;
+	first_soft_ack		= sp->ack.first_ack;
+	prev_pkt		= sp->ack.prev_ack;
+	nr_acks			= sp->ack.nr_acks;
+	hard_ack		= first_soft_ack - 1;
+	summary.acked_serial	= sp->ack.acked_serial;
+	summary.ack_reason	= (sp->ack.reason < RXRPC_ACK__INVALID ?
+				   sp->ack.reason : RXRPC_ACK__INVALID);
+
+	trace_rxrpc_rx_ack(call, sp);
+	rxrpc_inc_stat(call->rxnet, stat_rx_acks[summary.ack_reason]);
+	prefetch(call->tx_queue);
+
+	/* If we get an EXCEEDS_WINDOW ACK from the server, it probably
+	 * indicates that the client address changed due to NAT.  The server
+	 * lost the call because it switched to a different peer.
+	 */
+	if (unlikely(summary.ack_reason == RXRPC_ACK_EXCEEDS_WINDOW) &&
+	    hard_ack == 0 &&
+	    prev_pkt == 0 &&
+	    rxrpc_is_client_call(call)) {
+		rxrpc_set_call_completion(call, RXRPC_CALL_REMOTELY_ABORTED,
+					  0, -ENETRESET);
+		goto send_response;
 	}
-	offset += sizeof(buf.ack);
-
-	acked_serial = ntohl(buf.ack.serial);
-	first_soft_ack = ntohl(buf.ack.firstPacket);
-	hard_ack = first_soft_ack - 1;
-	nr_acks = buf.ack.nAcks;
-	summary.ack_reason = (buf.ack.reason < RXRPC_ACK__INVALID ?
-			      buf.ack.reason : RXRPC_ACK__INVALID);
-
-	trace_rxrpc_rx_ack(call, sp->hdr.serial, acked_serial,
-			   first_soft_ack, ntohl(buf.ack.previousPacket),
-			   summary.ack_reason, nr_acks);
-
-	if (buf.ack.reason == RXRPC_ACK_PING_RESPONSE)
-		rxrpc_input_ping_response(call, skb->tstamp, acked_serial,
-					  sp->hdr.serial);
-	if (buf.ack.reason == RXRPC_ACK_REQUESTED)
-		rxrpc_input_requested_ack(call, skb->tstamp, acked_serial,
-					  sp->hdr.serial);
-
-	if (buf.ack.reason == RXRPC_ACK_PING) {
-		_proto("Rx ACK %%%u PING Request", sp->hdr.serial);
-		rxrpc_propose_ACK(call, RXRPC_ACK_PING_RESPONSE,
-				  skew, sp->hdr.serial, true, true,
-				  rxrpc_propose_ack_respond_to_ping);
-	} else if (sp->hdr.flags & RXRPC_REQUEST_ACK) {
-		rxrpc_propose_ACK(call, RXRPC_ACK_REQUESTED,
-				  skew, sp->hdr.serial, true, true,
-				  rxrpc_propose_ack_respond_to_ack);
+
+	/* If we get an OUT_OF_SEQUENCE ACK from the server, that can also
+	 * indicate a change of address.  However, we can retransmit the call
+	 * if we still have it buffered to the beginning.
+	 */
+	if (unlikely(summary.ack_reason == RXRPC_ACK_OUT_OF_SEQUENCE) &&
+	    hard_ack == 0 &&
+	    prev_pkt == 0 &&
+	    call->tx_bottom == 0 &&
+	    rxrpc_is_client_call(call)) {
+		rxrpc_set_call_completion(call, RXRPC_CALL_REMOTELY_ABORTED,
+					  0, -ENETRESET);
+		goto send_response;
+	}
+
+	/* Discard any out-of-order or duplicate ACKs (outside lock). */
+	if (!rxrpc_is_ack_valid(call, hard_ack, prev_pkt)) {
+		trace_rxrpc_rx_discard_ack(call, summary.ack_serial, hard_ack, prev_pkt);
+		goto send_response; /* Still respond if requested. */
 	}
 
+	trailer.maxMTU = 0;
 	ioffset = offset + nr_acks + 3;
-	if (skb->len >= ioffset + sizeof(buf.info)) {
-		if (skb_copy_bits(skb, ioffset, &buf.info, sizeof(buf.info)) < 0)
-			return rxrpc_proto_abort("XAI", call, 0);
-		rxrpc_input_ackinfo(call, skb, &buf.info);
+	if (skb->len >= ioffset + sizeof(trailer) &&
+	    skb_copy_bits(skb, ioffset, &trailer, sizeof(trailer)) < 0)
+		return rxrpc_proto_abort(call, 0, rxrpc_badmsg_short_ack_trailer);
+
+	if (nr_acks > 0)
+		skb_condense(skb);
+
+	call->acks_latest_ts = ktime_get_real();
+	call->acks_hard_ack = hard_ack;
+	call->acks_prev_seq = prev_pkt;
+
+	if (summary.acked_serial) {
+		switch (summary.ack_reason) {
+		case RXRPC_ACK_PING_RESPONSE:
+			rxrpc_complete_rtt_probe(call, call->acks_latest_ts,
+						 summary.acked_serial, summary.ack_serial,
+						 rxrpc_rtt_rx_ping_response);
+			break;
+		default:
+			if (after(summary.acked_serial, call->acks_highest_serial))
+				call->acks_highest_serial = summary.acked_serial;
+			summary.rtt_sample_avail = true;
+			break;
+		}
 	}
 
-	if (first_soft_ack == 0)
-		return rxrpc_proto_abort("AK0", call, 0);
+	/* Parse rwind and mtu sizes if provided. */
+	if (trailer.maxMTU)
+		rxrpc_input_ack_trailer(call, skb, &trailer);
+
+	if (hard_ack + 1 == 0)
+		return rxrpc_proto_abort(call, 0, rxrpc_eproto_ackr_zero);
 
 	/* Ignore ACKs unless we are or have just been transmitting. */
-	switch (READ_ONCE(call->state)) {
+	switch (__rxrpc_call_state(call)) {
 	case RXRPC_CALL_CLIENT_SEND_REQUEST:
 	case RXRPC_CALL_CLIENT_AWAIT_REPLY:
 	case RXRPC_CALL_SERVER_SEND_REPLY:
 	case RXRPC_CALL_SERVER_AWAIT_ACK:
 		break;
 	default:
-		return;
+		goto send_response;
 	}
 
-	/* Discard any out-of-order or duplicate ACKs. */
-	if (before_eq(sp->hdr.serial, call->acks_latest)) {
-		_debug("discard ACK %d <= %d",
-		       sp->hdr.serial, call->acks_latest);
-		return;
-	}
-	call->acks_latest_ts = skb->tstamp;
-	call->acks_latest = sp->hdr.serial;
-
-	if (before(hard_ack, call->tx_hard_ack) ||
+	if (before(hard_ack, call->tx_bottom) ||
 	    after(hard_ack, call->tx_top))
-		return rxrpc_proto_abort("AKW", call, 0);
+		return rxrpc_proto_abort(call, 0, rxrpc_eproto_ackr_outside_window);
 	if (nr_acks > call->tx_top - hard_ack)
-		return rxrpc_proto_abort("AKN", call, 0);
-
-	if (after(hard_ack, call->tx_hard_ack))
-		rxrpc_rotate_tx_window(call, hard_ack, &summary);
+		return rxrpc_proto_abort(call, 0, rxrpc_eproto_ackr_sack_overflow);
 
-	if (nr_acks > 0) {
-		if (skb_copy_bits(skb, offset, buf.acks, nr_acks) < 0)
-			return rxrpc_proto_abort("XSA", call, 0);
-		rxrpc_input_soft_acks(call, buf.acks, first_soft_ack, nr_acks,
-				      &summary);
+	if (after(hard_ack, call->tx_bottom)) {
+		if (rxrpc_rotate_tx_window(call, hard_ack, &summary)) {
+			rxrpc_end_tx_phase(call, false, rxrpc_eproto_unexpected_ack);
+			goto send_response;
+		}
 	}
 
-	if (test_bit(RXRPC_CALL_TX_LAST, &call->flags)) {
-		rxrpc_end_tx_phase(call, false, "ETA");
-		return;
+	if (nr_acks > 0) {
+		if (offset > (int)skb->len - nr_acks)
+			return rxrpc_proto_abort(call, 0, rxrpc_eproto_ackr_short_sack);
+		rxrpc_input_soft_acks(call, &summary, skb);
 	}
 
-	if (call->rxtx_annotations[call->tx_top & RXRPC_RXTX_BUFF_MASK] &
-	    RXRPC_TX_ANNO_LAST &&
-	    summary.nr_acks == call->tx_top - hard_ack &&
+	if (test_bit(RXRPC_CALL_TX_LAST, &call->flags) &&
+	    call->acks_nr_sacks == call->tx_top - hard_ack &&
 	    rxrpc_is_client_call(call))
-		rxrpc_propose_ACK(call, RXRPC_ACK_PING, skew, sp->hdr.serial,
-				  false, true,
-				  rxrpc_propose_ack_ping_for_lost_reply);
+		rxrpc_propose_ping(call, summary.ack_serial,
+				   rxrpc_propose_ack_ping_for_lost_reply);
 
-	return rxrpc_congestion_management(call, skb, &summary, acked_serial);
+	/* Drive the congestion management algorithm first and then RACK-TLP as
+	 * the latter depends on the state/change in state in the former.
+	 */
+	rxrpc_congestion_management(call, &summary);
+	rxrpc_rack_detect_loss_and_arm_timer(call, &summary);
+	rxrpc_tlp_process_ack(call, &summary);
+	if (call->tlp_serial && after_eq(summary.acked_serial, call->tlp_serial))
+		call->tlp_serial = 0;
+
+send_response:
+	if (summary.ack_reason == RXRPC_ACK_PING)
+		rxrpc_send_ACK(call, RXRPC_ACK_PING_RESPONSE, summary.ack_serial,
+			       rxrpc_propose_ack_respond_to_ping);
+	else if (sp->hdr.flags & RXRPC_REQUEST_ACK)
+		rxrpc_send_ACK(call, RXRPC_ACK_REQUESTED, summary.ack_serial,
+			       rxrpc_propose_ack_respond_to_ack);
 }
 
 /*
@@ -869,13 +1206,9 @@ static void rxrpc_input_ack(struct rxrpc_call *call, struct sk_buff *skb,
 static void rxrpc_input_ackall(struct rxrpc_call *call, struct sk_buff *skb)
 {
 	struct rxrpc_ack_summary summary = { 0 };
-	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
-
-	_proto("Rx ACKALL %%%u", sp->hdr.serial);
 
-	rxrpc_rotate_tx_window(call, call->tx_top, &summary);
-	if (test_bit(RXRPC_CALL_TX_LAST, &call->flags))
-		rxrpc_end_tx_phase(call, false, "ETL");
+	if (rxrpc_rotate_tx_window(call, call->tx_top, &summary))
+		rxrpc_end_tx_phase(call, false, rxrpc_eproto_unexpected_ackall);
 }
 
 /*
@@ -884,386 +1217,83 @@ static void rxrpc_input_ackall(struct rxrpc_call *call, struct sk_buff *skb)
 static void rxrpc_input_abort(struct rxrpc_call *call, struct sk_buff *skb)
 {
 	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
-	__be32 wtmp;
-	u32 abort_code = RX_CALL_DEAD;
-
-	_enter("");
 
-	if (skb->len >= 4 &&
-	    skb_copy_bits(skb, sizeof(struct rxrpc_wire_header),
-			  &wtmp, sizeof(wtmp)) >= 0)
-		abort_code = ntohl(wtmp);
+	trace_rxrpc_rx_abort(call, sp->hdr.serial, skb->priority);
 
-	trace_rxrpc_rx_abort(call, sp->hdr.serial, abort_code);
-
-	_proto("Rx ABORT %%%u { %x }", sp->hdr.serial, abort_code);
-
-	if (rxrpc_set_call_completion(call, RXRPC_CALL_REMOTELY_ABORTED,
-				      abort_code, -ECONNABORTED))
-		rxrpc_notify_socket(call);
+	rxrpc_set_call_completion(call, RXRPC_CALL_REMOTELY_ABORTED,
+				  skb->priority, -ECONNABORTED);
 }
 
 /*
  * Process an incoming call packet.
  */
-static void rxrpc_input_call_packet(struct rxrpc_call *call,
-				    struct sk_buff *skb, u16 skew)
+void rxrpc_input_call_packet(struct rxrpc_call *call, struct sk_buff *skb)
 {
 	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
+	unsigned long timo;
 
 	_enter("%p,%p", call, skb);
 
+	if (sp->hdr.serviceId != call->dest_srx.srx_service)
+		call->dest_srx.srx_service = sp->hdr.serviceId;
+	if ((int)sp->hdr.serial - (int)call->rx_serial > 0)
+		call->rx_serial = sp->hdr.serial;
+	if (!test_bit(RXRPC_CALL_RX_HEARD, &call->flags))
+		set_bit(RXRPC_CALL_RX_HEARD, &call->flags);
+
+	timo = READ_ONCE(call->next_rx_timo);
+	if (timo) {
+		ktime_t delay = ms_to_ktime(timo);
+
+		call->expect_rx_by = ktime_add(ktime_get_real(), delay);
+		trace_rxrpc_timer_set(call, delay, rxrpc_timer_trace_expect_rx);
+	}
+
 	switch (sp->hdr.type) {
 	case RXRPC_PACKET_TYPE_DATA:
-		rxrpc_input_data(call, skb, skew);
-		break;
+		return rxrpc_input_data(call, skb);
 
 	case RXRPC_PACKET_TYPE_ACK:
-		rxrpc_input_ack(call, skb, skew);
-		break;
+		return rxrpc_input_ack(call, skb);
 
 	case RXRPC_PACKET_TYPE_BUSY:
-		_proto("Rx BUSY %%%u", sp->hdr.serial);
-
 		/* Just ignore BUSY packets from the server; the retry and
 		 * lifespan timers will take care of business.  BUSY packets
 		 * from the client don't make sense.
 		 */
-		break;
+		return;
 
 	case RXRPC_PACKET_TYPE_ABORT:
-		rxrpc_input_abort(call, skb);
-		break;
+		return rxrpc_input_abort(call, skb);
 
 	case RXRPC_PACKET_TYPE_ACKALL:
-		rxrpc_input_ackall(call, skb);
-		break;
+		return rxrpc_input_ackall(call, skb);
 
 	default:
 		break;
 	}
-
-	_leave("");
 }
 
 /*
- * Handle a new call on a channel implicitly completing the preceding call on
- * that channel.
+ * Handle a new service call on a channel implicitly completing the preceding
+ * call on that channel.  This does not apply to client conns.
  *
  * TODO: If callNumber > call_id + 1, renegotiate security.
  */
-static void rxrpc_input_implicit_end_call(struct rxrpc_connection *conn,
-					  struct rxrpc_call *call)
+void rxrpc_implicit_end_call(struct rxrpc_call *call, struct sk_buff *skb)
 {
-	switch (READ_ONCE(call->state)) {
+	switch (__rxrpc_call_state(call)) {
 	case RXRPC_CALL_SERVER_AWAIT_ACK:
 		rxrpc_call_completed(call);
-		break;
+		fallthrough;
 	case RXRPC_CALL_COMPLETE:
 		break;
 	default:
-		if (rxrpc_abort_call("IMP", call, 0, RX_CALL_DEAD, -ESHUTDOWN)) {
-			set_bit(RXRPC_CALL_EV_ABORT, &call->events);
-			rxrpc_queue_call(call);
-		}
-		break;
-	}
-
-	trace_rxrpc_improper_term(call);
-	__rxrpc_disconnect_call(conn, call);
-	rxrpc_notify_socket(call);
-}
-
-/*
- * post connection-level events to the connection
- * - this includes challenges, responses, some aborts and call terminal packet
- *   retransmission.
- */
-static void rxrpc_post_packet_to_conn(struct rxrpc_connection *conn,
-				      struct sk_buff *skb)
-{
-	_enter("%p,%p", conn, skb);
-
-	skb_queue_tail(&conn->rx_queue, skb);
-	rxrpc_queue_conn(conn);
-}
-
-/*
- * post endpoint-level events to the local endpoint
- * - this includes debug and version messages
- */
-static void rxrpc_post_packet_to_local(struct rxrpc_local *local,
-				       struct sk_buff *skb)
-{
-	_enter("%p,%p", local, skb);
-
-	skb_queue_tail(&local->event_queue, skb);
-	rxrpc_queue_local(local);
-}
-
-/*
- * put a packet up for transport-level abort
- */
-static void rxrpc_reject_packet(struct rxrpc_local *local, struct sk_buff *skb)
-{
-	CHECK_SLAB_OKAY(&local->usage);
-
-	skb_queue_tail(&local->reject_queue, skb);
-	rxrpc_queue_local(local);
-}
-
-/*
- * Extract the wire header from a packet and translate the byte order.
- */
-static noinline
-int rxrpc_extract_header(struct rxrpc_skb_priv *sp, struct sk_buff *skb)
-{
-	struct rxrpc_wire_header whdr;
-
-	/* dig out the RxRPC connection details */
-	if (skb_copy_bits(skb, 0, &whdr, sizeof(whdr)) < 0) {
-		trace_rxrpc_rx_eproto(NULL, sp->hdr.serial,
-				      tracepoint_string("bad_hdr"));
-		return -EBADMSG;
-	}
-
-	memset(sp, 0, sizeof(*sp));
-	sp->hdr.epoch		= ntohl(whdr.epoch);
-	sp->hdr.cid		= ntohl(whdr.cid);
-	sp->hdr.callNumber	= ntohl(whdr.callNumber);
-	sp->hdr.seq		= ntohl(whdr.seq);
-	sp->hdr.serial		= ntohl(whdr.serial);
-	sp->hdr.flags		= whdr.flags;
-	sp->hdr.type		= whdr.type;
-	sp->hdr.userStatus	= whdr.userStatus;
-	sp->hdr.securityIndex	= whdr.securityIndex;
-	sp->hdr._rsvd		= ntohs(whdr._rsvd);
-	sp->hdr.serviceId	= ntohs(whdr.serviceId);
-	return 0;
-}
-
-/*
- * handle data received on the local endpoint
- * - may be called in interrupt context
- *
- * The socket is locked by the caller and this prevents the socket from being
- * shut down and the local endpoint from going away, thus sk_user_data will not
- * be cleared until this function returns.
- */
-void rxrpc_data_ready(struct sock *udp_sk)
-{
-	struct rxrpc_connection *conn;
-	struct rxrpc_channel *chan;
-	struct rxrpc_call *call;
-	struct rxrpc_skb_priv *sp;
-	struct rxrpc_local *local = udp_sk->sk_user_data;
-	struct sk_buff *skb;
-	unsigned int channel;
-	int ret, skew;
-
-	_enter("%p", udp_sk);
-
-	ASSERT(!irqs_disabled());
-
-	skb = skb_recv_udp(udp_sk, 0, 1, &ret);
-	if (!skb) {
-		if (ret == -EAGAIN)
-			return;
-		_debug("UDP socket error %d", ret);
-		return;
-	}
-
-	rxrpc_new_skb(skb, rxrpc_skb_rx_received);
-
-	_net("recv skb %p", skb);
-
-	/* we'll probably need to checksum it (didn't call sock_recvmsg) */
-	if (skb_checksum_complete(skb)) {
-		rxrpc_free_skb(skb, rxrpc_skb_rx_freed);
-		__UDP_INC_STATS(&init_net, UDP_MIB_INERRORS, 0);
-		_leave(" [CSUM failed]");
-		return;
-	}
-
-	__UDP_INC_STATS(&init_net, UDP_MIB_INDATAGRAMS, 0);
-
-	/* The UDP protocol already released all skb resources;
-	 * we are free to add our own data there.
-	 */
-	sp = rxrpc_skb(skb);
-
-	/* dig out the RxRPC connection details */
-	if (rxrpc_extract_header(sp, skb) < 0)
-		goto bad_message;
-
-	if (IS_ENABLED(CONFIG_AF_RXRPC_INJECT_LOSS)) {
-		static int lose;
-		if ((lose++ & 7) == 7) {
-			trace_rxrpc_rx_lose(sp);
-			rxrpc_lose_skb(skb, rxrpc_skb_rx_lost);
-			return;
-		}
-	}
-
-	trace_rxrpc_rx_packet(sp);
-
-	_net("Rx RxRPC %s ep=%x call=%x:%x",
-	     sp->hdr.flags & RXRPC_CLIENT_INITIATED ? "ToServer" : "ToClient",
-	     sp->hdr.epoch, sp->hdr.cid, sp->hdr.callNumber);
-
-	if (sp->hdr.type >= RXRPC_N_PACKET_TYPES ||
-	    !((RXRPC_SUPPORTED_PACKET_TYPES >> sp->hdr.type) & 1)) {
-		_proto("Rx Bad Packet Type %u", sp->hdr.type);
-		goto bad_message;
-	}
-
-	switch (sp->hdr.type) {
-	case RXRPC_PACKET_TYPE_VERSION:
-		rxrpc_post_packet_to_local(local, skb);
-		goto out;
-
-	case RXRPC_PACKET_TYPE_BUSY:
-		if (sp->hdr.flags & RXRPC_CLIENT_INITIATED)
-			goto discard;
-
-	case RXRPC_PACKET_TYPE_DATA:
-		if (sp->hdr.callNumber == 0)
-			goto bad_message;
-		if (sp->hdr.flags & RXRPC_JUMBO_PACKET &&
-		    !rxrpc_validate_jumbo(skb))
-			goto bad_message;
+		rxrpc_abort_call(call, 0, RX_CALL_DEAD, -ESHUTDOWN,
+				 rxrpc_eproto_improper_term);
+		trace_rxrpc_improper_term(call);
 		break;
 	}
 
-	rcu_read_lock();
-
-	conn = rxrpc_find_connection_rcu(local, skb);
-	if (conn) {
-		if (sp->hdr.securityIndex != conn->security_ix)
-			goto wrong_security;
-
-		if (sp->hdr.serviceId != conn->service_id) {
-			if (!test_bit(RXRPC_CONN_PROBING_FOR_UPGRADE, &conn->flags) ||
-			    conn->service_id != conn->params.service_id)
-				goto reupgrade;
-			conn->service_id = sp->hdr.serviceId;
-		}
-		
-		if (sp->hdr.callNumber == 0) {
-			/* Connection-level packet */
-			_debug("CONN %p {%d}", conn, conn->debug_id);
-			rxrpc_post_packet_to_conn(conn, skb);
-			goto out_unlock;
-		}
-
-		/* Note the serial number skew here */
-		skew = (int)sp->hdr.serial - (int)conn->hi_serial;
-		if (skew >= 0) {
-			if (skew > 0)
-				conn->hi_serial = sp->hdr.serial;
-		} else {
-			skew = -skew;
-			skew = min(skew, 65535);
-		}
-
-		/* Call-bound packets are routed by connection channel. */
-		channel = sp->hdr.cid & RXRPC_CHANNELMASK;
-		chan = &conn->channels[channel];
-
-		/* Ignore really old calls */
-		if (sp->hdr.callNumber < chan->last_call)
-			goto discard_unlock;
-
-		if (sp->hdr.callNumber == chan->last_call) {
-			/* For the previous service call, if completed successfully, we
-			 * discard all further packets.
-			 */
-			if (rxrpc_conn_is_service(conn) &&
-			    (chan->last_type == RXRPC_PACKET_TYPE_ACK ||
-			     sp->hdr.type == RXRPC_PACKET_TYPE_ABORT))
-				goto discard_unlock;
-
-			/* But otherwise we need to retransmit the final packet from
-			 * data cached in the connection record.
-			 */
-			rxrpc_post_packet_to_conn(conn, skb);
-			goto out_unlock;
-		}
-
-		call = rcu_dereference(chan->call);
-
-		if (sp->hdr.callNumber > chan->call_id) {
-			if (!(sp->hdr.flags & RXRPC_CLIENT_INITIATED)) {
-				rcu_read_unlock();
-				goto reject_packet;
-			}
-			if (call)
-				rxrpc_input_implicit_end_call(conn, call);
-			call = NULL;
-		}
-
-		if (call && sp->hdr.serviceId != call->service_id)
-			call->service_id = sp->hdr.serviceId;
-	} else {
-		skew = 0;
-		call = NULL;
-	}
-
-	if (!call || atomic_read(&call->usage) == 0) {
-		if (!(sp->hdr.type & RXRPC_CLIENT_INITIATED) ||
-		    sp->hdr.callNumber == 0 ||
-		    sp->hdr.type != RXRPC_PACKET_TYPE_DATA)
-			goto bad_message_unlock;
-		if (sp->hdr.seq != 1)
-			goto discard_unlock;
-		call = rxrpc_new_incoming_call(local, conn, skb);
-		if (!call) {
-			rcu_read_unlock();
-			goto reject_packet;
-		}
-		rxrpc_send_ping(call, skb, skew);
-		mutex_unlock(&call->user_mutex);
-	}
-
-	rxrpc_input_call_packet(call, skb, skew);
-	goto discard_unlock;
-
-discard_unlock:
-	rcu_read_unlock();
-discard:
-	rxrpc_free_skb(skb, rxrpc_skb_rx_freed);
-out:
-	trace_rxrpc_rx_done(0, 0);
-	return;
-
-out_unlock:
-	rcu_read_unlock();
-	goto out;
-
-wrong_security:
-	rcu_read_unlock();
-	trace_rxrpc_abort("SEC", sp->hdr.cid, sp->hdr.callNumber, sp->hdr.seq,
-			  RXKADINCONSISTENCY, EBADMSG);
-	skb->priority = RXKADINCONSISTENCY;
-	goto post_abort;
-
-reupgrade:
-	rcu_read_unlock();
-	trace_rxrpc_abort("UPG", sp->hdr.cid, sp->hdr.callNumber, sp->hdr.seq,
-			  RX_PROTOCOL_ERROR, EBADMSG);
-	goto protocol_error;
-
-bad_message_unlock:
-	rcu_read_unlock();
-bad_message:
-	trace_rxrpc_abort("BAD", sp->hdr.cid, sp->hdr.callNumber, sp->hdr.seq,
-			  RX_PROTOCOL_ERROR, EBADMSG);
-protocol_error:
-	skb->priority = RX_PROTOCOL_ERROR;
-post_abort:
-	skb->mark = RXRPC_SKB_MARK_LOCAL_ABORT;
-reject_packet:
-	trace_rxrpc_rx_done(skb->mark, skb->priority);
-	rxrpc_reject_packet(local, skb);
-	_leave(" [badmsg]");
+	rxrpc_input_call_event(call);
 }