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eeaedc5449
Implement path-MTU probing (along the lines of RFC8899) by padding some of the PING ACKs we send. PING ACKs get their own individual responses quite apart from the acking of data (though, as ACKs, they fulfil that role also). The probing concentrates on packet sizes that correspond how many subpackets can be stuffed inside a jumbo packet as jumbo DATA packets are just aggregations of individual DATA packets and can be split easily for retransmission purposes. If we want to perform probing, we advertise this by setting the maximum number of jumbo subpackets to 0 in the ack trailer when we send an ACK and see if the peer is also advertising the service. This is interpreted by non-supporting Rx stacks as an indication that jumbo packets aren't supported. The MTU sizes advertised in the ACK trailer AF_RXRPC transmits are pegged at a maximum of 1444 unless pmtud is supported by both sides. Signed-off-by: David Howells <dhowells@redhat.com> cc: Marc Dionne <marc.dionne@auristor.com> cc: linux-afs@lists.infradead.org Link: https://patch.msgid.link/20241204074710.990092-10-dhowells@redhat.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
148 lines
3.9 KiB
C
148 lines
3.9 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/* sysctls for configuring RxRPC operating parameters
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*
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* Copyright (C) 2014 Red Hat, Inc. All Rights Reserved.
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* Written by David Howells (dhowells@redhat.com)
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*/
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#include <linux/sysctl.h>
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#include <net/sock.h>
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#include <net/af_rxrpc.h>
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#include "ar-internal.h"
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static struct ctl_table_header *rxrpc_sysctl_reg_table;
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static const unsigned int rxrpc_rx_mtu_min = 500;
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static const unsigned int rxrpc_jumbo_max = RXRPC_MAX_NR_JUMBO;
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static const unsigned int four = 4;
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static const unsigned int max_backlog = RXRPC_BACKLOG_MAX - 1;
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static const unsigned int n_65535 = 65535;
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static const unsigned int n_max_acks = 255;
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static const unsigned long one_ms = 1;
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static const unsigned long max_ms = 1000;
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static const unsigned long one_jiffy = 1;
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static const unsigned long max_jiffies = MAX_JIFFY_OFFSET;
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#ifdef CONFIG_AF_RXRPC_INJECT_RX_DELAY
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static const unsigned long max_500 = 500;
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#endif
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/*
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* RxRPC operating parameters.
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*
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* See Documentation/networking/rxrpc.rst and the variable definitions for more
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* information on the individual parameters.
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*/
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static struct ctl_table rxrpc_sysctl_table[] = {
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/* Values measured in milliseconds */
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{
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.procname = "soft_ack_delay",
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.data = &rxrpc_soft_ack_delay,
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.maxlen = sizeof(unsigned long),
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.mode = 0644,
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.proc_handler = proc_doulongvec_minmax,
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.extra1 = (void *)&one_ms,
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.extra2 = (void *)&max_ms,
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},
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{
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.procname = "idle_ack_delay",
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.data = &rxrpc_idle_ack_delay,
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.maxlen = sizeof(unsigned long),
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.mode = 0644,
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.proc_handler = proc_doulongvec_minmax,
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.extra1 = (void *)&one_ms,
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.extra2 = (void *)&max_ms,
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},
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{
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.procname = "idle_conn_expiry",
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.data = &rxrpc_conn_idle_client_expiry,
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.maxlen = sizeof(unsigned long),
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.mode = 0644,
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.proc_handler = proc_doulongvec_ms_jiffies_minmax,
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.extra1 = (void *)&one_jiffy,
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.extra2 = (void *)&max_jiffies,
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},
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{
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.procname = "idle_conn_fast_expiry",
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.data = &rxrpc_conn_idle_client_fast_expiry,
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.maxlen = sizeof(unsigned long),
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.mode = 0644,
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.proc_handler = proc_doulongvec_ms_jiffies_minmax,
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.extra1 = (void *)&one_jiffy,
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.extra2 = (void *)&max_jiffies,
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},
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/* Values used in milliseconds */
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#ifdef CONFIG_AF_RXRPC_INJECT_RX_DELAY
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{
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.procname = "inject_rx_delay",
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.data = &rxrpc_inject_rx_delay,
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.maxlen = sizeof(unsigned long),
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.mode = 0644,
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.proc_handler = proc_doulongvec_minmax,
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.extra1 = (void *)SYSCTL_LONG_ZERO,
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.extra2 = (void *)&max_500,
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},
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#endif
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/* Non-time values */
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{
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.procname = "reap_client_conns",
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.data = &rxrpc_reap_client_connections,
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.maxlen = sizeof(unsigned int),
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.mode = 0644,
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.proc_handler = proc_dointvec_minmax,
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.extra1 = (void *)SYSCTL_ONE,
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.extra2 = (void *)&n_65535,
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},
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{
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.procname = "max_backlog",
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.data = &rxrpc_max_backlog,
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.maxlen = sizeof(unsigned int),
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.mode = 0644,
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.proc_handler = proc_dointvec_minmax,
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.extra1 = (void *)&four,
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.extra2 = (void *)&max_backlog,
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},
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{
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.procname = "rx_window_size",
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.data = &rxrpc_rx_window_size,
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.maxlen = sizeof(unsigned int),
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.mode = 0644,
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.proc_handler = proc_dointvec_minmax,
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.extra1 = (void *)SYSCTL_ONE,
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.extra2 = (void *)&n_max_acks,
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},
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{
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.procname = "rx_mtu",
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.data = &rxrpc_rx_mtu,
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.maxlen = sizeof(unsigned int),
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.mode = 0644,
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.proc_handler = proc_dointvec_minmax,
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.extra1 = (void *)&rxrpc_rx_mtu_min,
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.extra2 = (void *)&n_65535,
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},
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{
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.procname = "rx_jumbo_max",
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.data = &rxrpc_rx_jumbo_max,
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.maxlen = sizeof(unsigned int),
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.mode = 0644,
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.proc_handler = proc_dointvec_minmax,
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.extra1 = (void *)SYSCTL_ONE,
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.extra2 = (void *)&rxrpc_jumbo_max,
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},
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};
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int __init rxrpc_sysctl_init(void)
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{
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rxrpc_sysctl_reg_table = register_net_sysctl(&init_net, "net/rxrpc",
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rxrpc_sysctl_table);
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if (!rxrpc_sysctl_reg_table)
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return -ENOMEM;
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return 0;
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}
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void rxrpc_sysctl_exit(void)
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{
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if (rxrpc_sysctl_reg_table)
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unregister_net_sysctl_table(rxrpc_sysctl_reg_table);
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}
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