kernel-ark/net/dccp/sysctl.c
Gerrit Renker 883ca833e5 dccp: Initialisation and type-checking of feature sysctls
This patch takes care of initialising and type-checking sysctls
related to feature negotiation. Type checking is important since some
of the sysctls now directly impact the feature-negotiation process.

The sysctls are initialised with the known default values for each
feature.  For the type-checking the value constraints from RFC 4340
are used:

 * Sequence Window uses the specified Wmin=32, the maximum is ulong (4 bytes),
   tested and confirmed that it works up to 4294967295 - for Gbps speed;
 * Ack Ratio is between 0 .. 0xffff (2-byte unsigned integer);
 * CCIDs are between 0 .. 255;
 * request_retries, retries1, retries2 also between 0..255 for good measure;
 * tx_qlen is checked to be non-negative;
 * sync_ratelimit remains as before.

Notes:
------
 1. Die s@sysctl_dccp_feat@sysctl_dccp@g since the sysctls are now in feat.c.
 2. As pointed out by Arnaldo, the pattern of type-checking repeats itself in
    other places, sometimes with exactly the same kind of definitions (e.g.
    "static int zero;"). It may be a good idea (kernel janitors?) to consolidate
    type checking. For the sake of keeping the changeset small and in order not
    to affect other subsystems, I have not strived to generalise here.

Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: David S. Miller <davem@davemloft.net>
2009-01-21 14:34:05 -08:00

123 lines
2.9 KiB
C

/*
* net/dccp/sysctl.c
*
* An implementation of the DCCP protocol
* Arnaldo Carvalho de Melo <acme@mandriva.com>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License v2
* as published by the Free Software Foundation.
*/
#include <linux/mm.h>
#include <linux/sysctl.h>
#include "dccp.h"
#include "feat.h"
#ifndef CONFIG_SYSCTL
#error This file should not be compiled without CONFIG_SYSCTL defined
#endif
/* Boundary values */
static int zero = 0,
u8_max = 0xFF;
static unsigned long seqw_min = 32;
static struct ctl_table dccp_default_table[] = {
{
.procname = "seq_window",
.data = &sysctl_dccp_sequence_window,
.maxlen = sizeof(sysctl_dccp_sequence_window),
.mode = 0644,
.proc_handler = proc_doulongvec_minmax,
.extra1 = &seqw_min, /* RFC 4340, 7.5.2 */
},
{
.procname = "rx_ccid",
.data = &sysctl_dccp_rx_ccid,
.maxlen = sizeof(sysctl_dccp_rx_ccid),
.mode = 0644,
.proc_handler = proc_dointvec_minmax,
.extra1 = &zero,
.extra2 = &u8_max, /* RFC 4340, 10. */
},
{
.procname = "tx_ccid",
.data = &sysctl_dccp_tx_ccid,
.maxlen = sizeof(sysctl_dccp_tx_ccid),
.mode = 0644,
.proc_handler = proc_dointvec_minmax,
.extra1 = &zero,
.extra2 = &u8_max, /* RFC 4340, 10. */
},
{
.procname = "request_retries",
.data = &sysctl_dccp_request_retries,
.maxlen = sizeof(sysctl_dccp_request_retries),
.mode = 0644,
.proc_handler = proc_dointvec_minmax,
.extra1 = &zero,
.extra2 = &u8_max,
},
{
.procname = "retries1",
.data = &sysctl_dccp_retries1,
.maxlen = sizeof(sysctl_dccp_retries1),
.mode = 0644,
.proc_handler = proc_dointvec_minmax,
.extra1 = &zero,
.extra2 = &u8_max,
},
{
.procname = "retries2",
.data = &sysctl_dccp_retries2,
.maxlen = sizeof(sysctl_dccp_retries2),
.mode = 0644,
.proc_handler = proc_dointvec_minmax,
.extra1 = &zero,
.extra2 = &u8_max,
},
{
.procname = "tx_qlen",
.data = &sysctl_dccp_tx_qlen,
.maxlen = sizeof(sysctl_dccp_tx_qlen),
.mode = 0644,
.proc_handler = proc_dointvec_minmax,
.extra1 = &zero,
},
{
.procname = "sync_ratelimit",
.data = &sysctl_dccp_sync_ratelimit,
.maxlen = sizeof(sysctl_dccp_sync_ratelimit),
.mode = 0644,
.proc_handler = proc_dointvec_ms_jiffies,
},
{ .ctl_name = 0, }
};
static struct ctl_path dccp_path[] = {
{ .procname = "net", .ctl_name = CTL_NET, },
{ .procname = "dccp", .ctl_name = NET_DCCP, },
{ .procname = "default", .ctl_name = NET_DCCP_DEFAULT, },
{ }
};
static struct ctl_table_header *dccp_table_header;
int __init dccp_sysctl_init(void)
{
dccp_table_header = register_sysctl_paths(dccp_path,
dccp_default_table);
return dccp_table_header != NULL ? 0 : -ENOMEM;
}
void dccp_sysctl_exit(void)
{
if (dccp_table_header != NULL) {
unregister_sysctl_table(dccp_table_header);
dccp_table_header = NULL;
}
}