linux/net/rxrpc/misc.c
David Howells 70790dbe3f rxrpc: Pass the last Tx packet marker in the annotation buffer
When the last packet of data to be transmitted on a call is queued, tx_top
is set and then the RXRPC_CALL_TX_LAST flag is set.  Unfortunately, this
leaves a race in the ACK processing side of things because the flag affects
the interpretation of tx_top and also allows us to start receiving reply
data before we've finished transmitting.

To fix this, make the following changes:

 (1) rxrpc_queue_packet() now sets a marker in the annotation buffer
     instead of setting the RXRPC_CALL_TX_LAST flag.

 (2) rxrpc_rotate_tx_window() detects the marker and sets the flag in the
     same context as the routines that use it.

 (3) rxrpc_end_tx_phase() is simplified to just shift the call state.
     The Tx window must have been rotated before calling to discard the
     last packet.

 (4) rxrpc_receiving_reply() is added to handle the arrival of the first
     DATA packet of a reply to a client call (which is an implicit ACK of
     the Tx phase).

 (5) The last part of rxrpc_input_ack() is reordered to perform Tx
     rotation, then soft-ACK application and then to end the phase if we've
     rotated the last packet.  In the event of a terminal ACK, the soft-ACK
     application will be skipped as nAcks should be 0.

 (6) rxrpc_input_ackall() now has to rotate as well as ending the phase.

In addition:

 (7) Alter the transmit tracepoint to log the rotation of the last packet.

 (8) Remove the no-longer relevant queue_reqack tracepoint note.  The
     ACK-REQUESTED packet header flag is now set as needed when we actually
     transmit the packet and may vary by retransmission.

Signed-off-by: David Howells <dhowells@redhat.com>
2016-09-23 15:49:19 +01:00

197 lines
5.9 KiB
C

/* Miscellaneous bits
*
* Copyright (C) 2016 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 Licence
* as published by the Free Software Foundation; either version
* 2 of the Licence, or (at your option) any later version.
*/
#include <linux/kernel.h>
#include <net/sock.h>
#include <net/af_rxrpc.h>
#include "ar-internal.h"
/*
* The maximum listening backlog queue size that may be set on a socket by
* listen().
*/
unsigned int rxrpc_max_backlog __read_mostly = 10;
/*
* How long to wait before scheduling ACK generation after seeing a
* packet with RXRPC_REQUEST_ACK set (in jiffies).
*/
unsigned int rxrpc_requested_ack_delay = 1;
/*
* How long to wait before scheduling an ACK with subtype DELAY (in jiffies).
*
* We use this when we've received new data packets. If those packets aren't
* all consumed within this time we will send a DELAY ACK if an ACK was not
* requested to let the sender know it doesn't need to resend.
*/
unsigned int rxrpc_soft_ack_delay = 1 * HZ;
/*
* How long to wait before scheduling an ACK with subtype IDLE (in jiffies).
*
* We use this when we've consumed some previously soft-ACK'd packets when
* further packets aren't immediately received to decide when to send an IDLE
* ACK let the other end know that it can free up its Tx buffer space.
*/
unsigned int rxrpc_idle_ack_delay = 0.5 * HZ;
/*
* Receive window size in packets. This indicates the maximum number of
* unconsumed received packets we're willing to retain in memory. Once this
* limit is hit, we should generate an EXCEEDS_WINDOW ACK and discard further
* packets.
*/
unsigned int rxrpc_rx_window_size = RXRPC_INIT_RX_WINDOW_SIZE;
#if (RXRPC_RXTX_BUFF_SIZE - 1) < RXRPC_INIT_RX_WINDOW_SIZE
#error Need to reduce RXRPC_INIT_RX_WINDOW_SIZE
#endif
/*
* Maximum Rx MTU size. This indicates to the sender the size of jumbo packet
* made by gluing normal packets together that we're willing to handle.
*/
unsigned int rxrpc_rx_mtu = 5692;
/*
* The maximum number of fragments in a received jumbo packet that we tell the
* sender that we're willing to handle.
*/
unsigned int rxrpc_rx_jumbo_max = 4;
/*
* Time till packet resend (in milliseconds).
*/
unsigned int rxrpc_resend_timeout = 4 * 1000;
const char *const rxrpc_pkts[] = {
"?00",
"DATA", "ACK", "BUSY", "ABORT", "ACKALL", "CHALL", "RESP", "DEBUG",
"?09", "?10", "?11", "?12", "VERSION", "?14", "?15"
};
const s8 rxrpc_ack_priority[] = {
[0] = 0,
[RXRPC_ACK_DELAY] = 1,
[RXRPC_ACK_REQUESTED] = 2,
[RXRPC_ACK_IDLE] = 3,
[RXRPC_ACK_DUPLICATE] = 4,
[RXRPC_ACK_OUT_OF_SEQUENCE] = 5,
[RXRPC_ACK_EXCEEDS_WINDOW] = 6,
[RXRPC_ACK_NOSPACE] = 7,
[RXRPC_ACK_PING_RESPONSE] = 8,
[RXRPC_ACK_PING] = 9,
};
const char *rxrpc_acks(u8 reason)
{
static const char *const str[] = {
"---", "REQ", "DUP", "OOS", "WIN", "MEM", "PNG", "PNR", "DLY",
"IDL", "-?-"
};
if (reason >= ARRAY_SIZE(str))
reason = ARRAY_SIZE(str) - 1;
return str[reason];
}
const char rxrpc_skb_traces[rxrpc_skb__nr_trace][7] = {
[rxrpc_skb_rx_cleaned] = "Rx CLN",
[rxrpc_skb_rx_freed] = "Rx FRE",
[rxrpc_skb_rx_got] = "Rx GOT",
[rxrpc_skb_rx_lost] = "Rx *L*",
[rxrpc_skb_rx_received] = "Rx RCV",
[rxrpc_skb_rx_purged] = "Rx PUR",
[rxrpc_skb_rx_rotated] = "Rx ROT",
[rxrpc_skb_rx_seen] = "Rx SEE",
[rxrpc_skb_tx_cleaned] = "Tx CLN",
[rxrpc_skb_tx_freed] = "Tx FRE",
[rxrpc_skb_tx_got] = "Tx GOT",
[rxrpc_skb_tx_lost] = "Tx *L*",
[rxrpc_skb_tx_new] = "Tx NEW",
[rxrpc_skb_tx_rotated] = "Tx ROT",
[rxrpc_skb_tx_seen] = "Tx SEE",
};
const char rxrpc_conn_traces[rxrpc_conn__nr_trace][4] = {
[rxrpc_conn_new_client] = "NWc",
[rxrpc_conn_new_service] = "NWs",
[rxrpc_conn_queued] = "QUE",
[rxrpc_conn_seen] = "SEE",
[rxrpc_conn_got] = "GOT",
[rxrpc_conn_put_client] = "PTc",
[rxrpc_conn_put_service] = "PTs",
};
const char rxrpc_client_traces[rxrpc_client__nr_trace][7] = {
[rxrpc_client_activate_chans] = "Activa",
[rxrpc_client_alloc] = "Alloc ",
[rxrpc_client_chan_activate] = "ChActv",
[rxrpc_client_chan_disconnect] = "ChDisc",
[rxrpc_client_chan_pass] = "ChPass",
[rxrpc_client_chan_unstarted] = "ChUnst",
[rxrpc_client_cleanup] = "Clean ",
[rxrpc_client_count] = "Count ",
[rxrpc_client_discard] = "Discar",
[rxrpc_client_duplicate] = "Duplic",
[rxrpc_client_exposed] = "Expose",
[rxrpc_client_replace] = "Replac",
[rxrpc_client_to_active] = "->Actv",
[rxrpc_client_to_culled] = "->Cull",
[rxrpc_client_to_idle] = "->Idle",
[rxrpc_client_to_inactive] = "->Inac",
[rxrpc_client_to_waiting] = "->Wait",
[rxrpc_client_uncount] = "Uncoun",
};
const char rxrpc_transmit_traces[rxrpc_transmit__nr_trace][4] = {
[rxrpc_transmit_wait] = "WAI",
[rxrpc_transmit_queue] = "QUE",
[rxrpc_transmit_queue_last] = "QLS",
[rxrpc_transmit_rotate] = "ROT",
[rxrpc_transmit_rotate_last] = "RLS",
[rxrpc_transmit_await_reply] = "AWR",
[rxrpc_transmit_end] = "END",
};
const char rxrpc_receive_traces[rxrpc_receive__nr_trace][4] = {
[rxrpc_receive_incoming] = "INC",
[rxrpc_receive_queue] = "QUE",
[rxrpc_receive_queue_last] = "QLS",
[rxrpc_receive_front] = "FRN",
[rxrpc_receive_rotate] = "ROT",
[rxrpc_receive_end] = "END",
};
const char rxrpc_recvmsg_traces[rxrpc_recvmsg__nr_trace][5] = {
[rxrpc_recvmsg_enter] = "ENTR",
[rxrpc_recvmsg_wait] = "WAIT",
[rxrpc_recvmsg_dequeue] = "DEQU",
[rxrpc_recvmsg_hole] = "HOLE",
[rxrpc_recvmsg_next] = "NEXT",
[rxrpc_recvmsg_cont] = "CONT",
[rxrpc_recvmsg_full] = "FULL",
[rxrpc_recvmsg_data_return] = "DATA",
[rxrpc_recvmsg_terminal] = "TERM",
[rxrpc_recvmsg_to_be_accepted] = "TBAC",
[rxrpc_recvmsg_return] = "RETN",
};
const char rxrpc_rtt_tx_traces[rxrpc_rtt_tx__nr_trace][5] = {
[rxrpc_rtt_tx_ping] = "PING",
[rxrpc_rtt_tx_data] = "DATA",
};
const char rxrpc_rtt_rx_traces[rxrpc_rtt_rx__nr_trace][5] = {
[rxrpc_rtt_rx_ping_response] = "PONG",
[rxrpc_rtt_rx_requested_ack] = "RACK",
};