358 lines
9.6 KiB
C
358 lines
9.6 KiB
C
/* Management of Tx window, Tx resend, ACKs and out-of-sequence reception
|
|
*
|
|
* Copyright (C) 2007 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/circ_buf.h>
|
|
#include <linux/net.h>
|
|
#include <linux/skbuff.h>
|
|
#include <linux/slab.h>
|
|
#include <linux/udp.h>
|
|
#include <net/sock.h>
|
|
#include <net/af_rxrpc.h>
|
|
#include "ar-internal.h"
|
|
|
|
/*
|
|
* Set the timer
|
|
*/
|
|
void rxrpc_set_timer(struct rxrpc_call *call, enum rxrpc_timer_trace why)
|
|
{
|
|
unsigned long t, now = jiffies;
|
|
|
|
read_lock_bh(&call->state_lock);
|
|
|
|
if (call->state < RXRPC_CALL_COMPLETE) {
|
|
t = call->expire_at;
|
|
if (time_before_eq(t, now))
|
|
goto out;
|
|
|
|
if (time_after(call->resend_at, now) &&
|
|
time_before(call->resend_at, t))
|
|
t = call->resend_at;
|
|
|
|
if (time_after(call->ack_at, now) &&
|
|
time_before(call->ack_at, t))
|
|
t = call->ack_at;
|
|
|
|
if (call->timer.expires != t || !timer_pending(&call->timer)) {
|
|
mod_timer(&call->timer, t);
|
|
trace_rxrpc_timer(call, why, now);
|
|
}
|
|
}
|
|
|
|
out:
|
|
read_unlock_bh(&call->state_lock);
|
|
}
|
|
|
|
/*
|
|
* propose an ACK be sent
|
|
*/
|
|
static void __rxrpc_propose_ACK(struct rxrpc_call *call, u8 ack_reason,
|
|
u16 skew, u32 serial, bool immediate,
|
|
bool background,
|
|
enum rxrpc_propose_ack_trace why)
|
|
{
|
|
enum rxrpc_propose_ack_outcome outcome = rxrpc_propose_ack_use;
|
|
unsigned long now, ack_at, expiry = rxrpc_soft_ack_delay;
|
|
s8 prior = rxrpc_ack_priority[ack_reason];
|
|
|
|
/* Update DELAY, IDLE, REQUESTED and PING_RESPONSE ACK serial
|
|
* numbers, but we don't alter the timeout.
|
|
*/
|
|
_debug("prior %u %u vs %u %u",
|
|
ack_reason, prior,
|
|
call->ackr_reason, rxrpc_ack_priority[call->ackr_reason]);
|
|
if (ack_reason == call->ackr_reason) {
|
|
if (RXRPC_ACK_UPDATEABLE & (1 << ack_reason)) {
|
|
outcome = rxrpc_propose_ack_update;
|
|
call->ackr_serial = serial;
|
|
call->ackr_skew = skew;
|
|
}
|
|
if (!immediate)
|
|
goto trace;
|
|
} else if (prior > rxrpc_ack_priority[call->ackr_reason]) {
|
|
call->ackr_reason = ack_reason;
|
|
call->ackr_serial = serial;
|
|
call->ackr_skew = skew;
|
|
} else {
|
|
outcome = rxrpc_propose_ack_subsume;
|
|
}
|
|
|
|
switch (ack_reason) {
|
|
case RXRPC_ACK_REQUESTED:
|
|
if (rxrpc_requested_ack_delay < expiry)
|
|
expiry = rxrpc_requested_ack_delay;
|
|
if (serial == 1)
|
|
immediate = false;
|
|
break;
|
|
|
|
case RXRPC_ACK_DELAY:
|
|
if (rxrpc_soft_ack_delay < expiry)
|
|
expiry = rxrpc_soft_ack_delay;
|
|
break;
|
|
|
|
case RXRPC_ACK_PING:
|
|
case RXRPC_ACK_IDLE:
|
|
if (rxrpc_idle_ack_delay < expiry)
|
|
expiry = rxrpc_idle_ack_delay;
|
|
break;
|
|
|
|
default:
|
|
immediate = true;
|
|
break;
|
|
}
|
|
|
|
now = jiffies;
|
|
if (test_bit(RXRPC_CALL_EV_ACK, &call->events)) {
|
|
_debug("already scheduled");
|
|
} else if (immediate || expiry == 0) {
|
|
_debug("immediate ACK %lx", call->events);
|
|
if (!test_and_set_bit(RXRPC_CALL_EV_ACK, &call->events) &&
|
|
background)
|
|
rxrpc_queue_call(call);
|
|
} else {
|
|
ack_at = now + expiry;
|
|
_debug("deferred ACK %ld < %ld", expiry, call->ack_at - now);
|
|
if (time_before(ack_at, call->ack_at)) {
|
|
call->ack_at = ack_at;
|
|
rxrpc_set_timer(call, rxrpc_timer_set_for_ack);
|
|
}
|
|
}
|
|
|
|
trace:
|
|
trace_rxrpc_propose_ack(call, why, ack_reason, serial, immediate,
|
|
background, outcome);
|
|
}
|
|
|
|
/*
|
|
* propose an ACK be sent, locking the call structure
|
|
*/
|
|
void rxrpc_propose_ACK(struct rxrpc_call *call, u8 ack_reason,
|
|
u16 skew, u32 serial, bool immediate, bool background,
|
|
enum rxrpc_propose_ack_trace why)
|
|
{
|
|
spin_lock_bh(&call->lock);
|
|
__rxrpc_propose_ACK(call, ack_reason, skew, serial,
|
|
immediate, background, why);
|
|
spin_unlock_bh(&call->lock);
|
|
}
|
|
|
|
/*
|
|
* Handle congestion being detected by the retransmit timeout.
|
|
*/
|
|
static void rxrpc_congestion_timeout(struct rxrpc_call *call)
|
|
{
|
|
set_bit(RXRPC_CALL_RETRANS_TIMEOUT, &call->flags);
|
|
}
|
|
|
|
/*
|
|
* Perform retransmission of NAK'd and unack'd packets.
|
|
*/
|
|
static void rxrpc_resend(struct rxrpc_call *call)
|
|
{
|
|
struct rxrpc_skb_priv *sp;
|
|
struct sk_buff *skb;
|
|
rxrpc_seq_t cursor, seq, top;
|
|
ktime_t now = ktime_get_real(), max_age, oldest, resend_at, ack_ts;
|
|
int ix;
|
|
u8 annotation, anno_type, retrans = 0, unacked = 0;
|
|
|
|
_enter("{%d,%d}", call->tx_hard_ack, call->tx_top);
|
|
|
|
max_age = ktime_sub_ms(now, rxrpc_resend_timeout);
|
|
|
|
spin_lock_bh(&call->lock);
|
|
|
|
cursor = call->tx_hard_ack;
|
|
top = call->tx_top;
|
|
ASSERT(before_eq(cursor, top));
|
|
if (cursor == top)
|
|
goto out_unlock;
|
|
|
|
/* Scan the packet list without dropping the lock and decide which of
|
|
* the packets in the Tx buffer we're going to resend and what the new
|
|
* resend timeout will be.
|
|
*/
|
|
oldest = now;
|
|
for (seq = cursor + 1; before_eq(seq, top); seq++) {
|
|
ix = seq & RXRPC_RXTX_BUFF_MASK;
|
|
annotation = call->rxtx_annotations[ix];
|
|
anno_type = annotation & RXRPC_TX_ANNO_MASK;
|
|
annotation &= ~RXRPC_TX_ANNO_MASK;
|
|
if (anno_type == RXRPC_TX_ANNO_ACK)
|
|
continue;
|
|
|
|
skb = call->rxtx_buffer[ix];
|
|
rxrpc_see_skb(skb, rxrpc_skb_tx_seen);
|
|
sp = rxrpc_skb(skb);
|
|
|
|
if (anno_type == RXRPC_TX_ANNO_UNACK) {
|
|
if (ktime_after(skb->tstamp, max_age)) {
|
|
if (ktime_before(skb->tstamp, oldest))
|
|
oldest = skb->tstamp;
|
|
continue;
|
|
}
|
|
if (!(annotation & RXRPC_TX_ANNO_RESENT))
|
|
unacked++;
|
|
}
|
|
|
|
/* Okay, we need to retransmit a packet. */
|
|
call->rxtx_annotations[ix] = RXRPC_TX_ANNO_RETRANS | annotation;
|
|
retrans++;
|
|
trace_rxrpc_retransmit(call, seq, annotation | anno_type,
|
|
ktime_to_ns(ktime_sub(skb->tstamp, max_age)));
|
|
}
|
|
|
|
resend_at = ktime_add_ms(oldest, rxrpc_resend_timeout);
|
|
call->resend_at = jiffies +
|
|
nsecs_to_jiffies(ktime_to_ns(ktime_sub(resend_at, now))) +
|
|
1; /* We have to make sure that the calculated jiffies value
|
|
* falls at or after the nsec value, or we shall loop
|
|
* ceaselessly because the timer times out, but we haven't
|
|
* reached the nsec timeout yet.
|
|
*/
|
|
|
|
if (unacked)
|
|
rxrpc_congestion_timeout(call);
|
|
|
|
/* If there was nothing that needed retransmission then it's likely
|
|
* that an ACK got lost somewhere. Send a ping to find out instead of
|
|
* retransmitting data.
|
|
*/
|
|
if (!retrans) {
|
|
rxrpc_set_timer(call, rxrpc_timer_set_for_resend);
|
|
spin_unlock_bh(&call->lock);
|
|
ack_ts = ktime_sub(now, call->acks_latest_ts);
|
|
if (ktime_to_ns(ack_ts) < call->peer->rtt)
|
|
goto out;
|
|
rxrpc_propose_ACK(call, RXRPC_ACK_PING, 0, 0, true, false,
|
|
rxrpc_propose_ack_ping_for_lost_ack);
|
|
rxrpc_send_call_packet(call, RXRPC_PACKET_TYPE_ACK);
|
|
goto out;
|
|
}
|
|
|
|
/* Now go through the Tx window and perform the retransmissions. We
|
|
* have to drop the lock for each send. If an ACK comes in whilst the
|
|
* lock is dropped, it may clear some of the retransmission markers for
|
|
* packets that it soft-ACKs.
|
|
*/
|
|
for (seq = cursor + 1; before_eq(seq, top); seq++) {
|
|
ix = seq & RXRPC_RXTX_BUFF_MASK;
|
|
annotation = call->rxtx_annotations[ix];
|
|
anno_type = annotation & RXRPC_TX_ANNO_MASK;
|
|
if (anno_type != RXRPC_TX_ANNO_RETRANS)
|
|
continue;
|
|
|
|
skb = call->rxtx_buffer[ix];
|
|
rxrpc_get_skb(skb, rxrpc_skb_tx_got);
|
|
spin_unlock_bh(&call->lock);
|
|
|
|
if (rxrpc_send_data_packet(call, skb) < 0) {
|
|
rxrpc_free_skb(skb, rxrpc_skb_tx_freed);
|
|
return;
|
|
}
|
|
|
|
if (rxrpc_is_client_call(call))
|
|
rxrpc_expose_client_call(call);
|
|
|
|
rxrpc_free_skb(skb, rxrpc_skb_tx_freed);
|
|
spin_lock_bh(&call->lock);
|
|
|
|
/* We need to clear the retransmit state, but there are two
|
|
* things we need to be aware of: A new ACK/NAK might have been
|
|
* received and the packet might have been hard-ACK'd (in which
|
|
* case it will no longer be in the buffer).
|
|
*/
|
|
if (after(seq, call->tx_hard_ack)) {
|
|
annotation = call->rxtx_annotations[ix];
|
|
anno_type = annotation & RXRPC_TX_ANNO_MASK;
|
|
if (anno_type == RXRPC_TX_ANNO_RETRANS ||
|
|
anno_type == RXRPC_TX_ANNO_NAK) {
|
|
annotation &= ~RXRPC_TX_ANNO_MASK;
|
|
annotation |= RXRPC_TX_ANNO_UNACK;
|
|
}
|
|
annotation |= RXRPC_TX_ANNO_RESENT;
|
|
call->rxtx_annotations[ix] = annotation;
|
|
}
|
|
|
|
if (after(call->tx_hard_ack, seq))
|
|
seq = call->tx_hard_ack;
|
|
}
|
|
|
|
out_unlock:
|
|
spin_unlock_bh(&call->lock);
|
|
out:
|
|
_leave("");
|
|
}
|
|
|
|
/*
|
|
* Handle retransmission and deferred ACK/abort generation.
|
|
*/
|
|
void rxrpc_process_call(struct work_struct *work)
|
|
{
|
|
struct rxrpc_call *call =
|
|
container_of(work, struct rxrpc_call, processor);
|
|
unsigned long now;
|
|
|
|
rxrpc_see_call(call);
|
|
|
|
//printk("\n--------------------\n");
|
|
_enter("{%d,%s,%lx}",
|
|
call->debug_id, rxrpc_call_states[call->state], call->events);
|
|
|
|
recheck_state:
|
|
if (test_and_clear_bit(RXRPC_CALL_EV_ABORT, &call->events)) {
|
|
rxrpc_send_call_packet(call, RXRPC_PACKET_TYPE_ABORT);
|
|
goto recheck_state;
|
|
}
|
|
|
|
if (call->state == RXRPC_CALL_COMPLETE) {
|
|
del_timer_sync(&call->timer);
|
|
goto out_put;
|
|
}
|
|
|
|
now = jiffies;
|
|
if (time_after_eq(now, call->expire_at)) {
|
|
rxrpc_abort_call("EXP", call, 0, RX_CALL_TIMEOUT, ETIME);
|
|
set_bit(RXRPC_CALL_EV_ABORT, &call->events);
|
|
goto recheck_state;
|
|
}
|
|
|
|
if (test_and_clear_bit(RXRPC_CALL_EV_ACK, &call->events) ||
|
|
time_after_eq(now, call->ack_at)) {
|
|
call->ack_at = call->expire_at;
|
|
if (call->ackr_reason) {
|
|
rxrpc_send_call_packet(call, RXRPC_PACKET_TYPE_ACK);
|
|
goto recheck_state;
|
|
}
|
|
}
|
|
|
|
if (test_and_clear_bit(RXRPC_CALL_EV_RESEND, &call->events) ||
|
|
time_after_eq(now, call->resend_at)) {
|
|
rxrpc_resend(call);
|
|
goto recheck_state;
|
|
}
|
|
|
|
rxrpc_set_timer(call, rxrpc_timer_set_for_resend);
|
|
|
|
/* other events may have been raised since we started checking */
|
|
if (call->events && call->state < RXRPC_CALL_COMPLETE) {
|
|
__rxrpc_queue_call(call);
|
|
goto out;
|
|
}
|
|
|
|
out_put:
|
|
rxrpc_put_call(call, rxrpc_call_put);
|
|
out:
|
|
_leave("");
|
|
}
|