.\" $OpenBSD: sysctl.3,v 1.285 2017/10/28 20:16:13 mpi Exp $ .\" .\" Copyright (c) 1993 .\" The Regents of the University of California. All rights reserved. .\" .\" Redistribution and use in source and binary forms, with or without .\" modification, are permitted provided that the following conditions .\" are met: .\" 1. Redistributions of source code must retain the above copyright .\" notice, this list of conditions and the following disclaimer. .\" 2. Redistributions in binary form must reproduce the above copyright .\" notice, this list of conditions and the following disclaimer in the .\" documentation and/or other materials provided with the distribution. .\" 3. Neither the name of the University nor the names of its contributors .\" may be used to endorse or promote products derived from this software .\" without specific prior written permission. .\" .\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND .\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE .\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE .\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE .\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL .\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS .\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) .\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT .\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF .\" SUCH DAMAGE. .\" .Dd $Mdocdate: October 28 2017 $ .Dt SYSCTL 3 .Os .Sh NAME .Nm sysctl .Nd get or set system information .Sh SYNOPSIS .In sys/types.h .In sys/sysctl.h .Ft int .Fn sysctl "const int *name" "u_int namelen" "void *oldp" "size_t *oldlenp" "void *newp" "size_t newlen" .Sh DESCRIPTION The .Fn sysctl function retrieves system information and allows processes with appropriate privileges to set system information. The information available from .Fn sysctl consists of integers, strings, and tables. Information may be retrieved and set using the .Xr sysctl 8 utility; the variable names used by this utility are given here in parentheses. .Pp Unless explicitly noted below, .Fn sysctl returns a consistent snapshot of the data requested. Consistency is obtained by locking the destination buffer into memory so that the data may be copied out without blocking. Calls to .Fn sysctl are serialized to avoid deadlock. .Pp The state is described using a .Dq Management Information Base (MIB) style name, listed in .Fa name , which is a .Fa namelen length array of integers. .Pp The information is copied into the buffer specified by .Fa oldp . The size of the buffer is given by the location specified by .Fa oldlenp before the call, and that location gives the amount of data copied after a successful call. If the amount of data available is greater than the size of the buffer supplied, the call supplies as much data as fits in the buffer provided and returns with the error code .Er ENOMEM . If the old value is not desired, .Fa oldp and .Fa oldlenp should be set to .Dv NULL . .Pp The size of the available data can be determined by calling .Fn sysctl with a .Dv NULL parameter for .Fa oldp . The size of the available data will be returned in the location pointed to by .Fa oldlenp . For some operations, the amount of space may change often. For these operations, the system attempts to round up so that the returned size is large enough for a call to return the data shortly thereafter. .Pp The terminating NUL character is included in the lengths of string values. .Pp To set a new value, .Fa newp is set to point to a buffer of length .Fa newlen from which the requested value is to be taken. If a new value is not to be set, .Fa newp should be set to .Dv NULL and .Fa newlen set to 0. .Pp The top level names are defined with a .Dv CTL_ prefix in .In sys/sysctl.h , and are as follows. The next and subsequent levels down are found in the include files listed here, and described in separate sections below. .Bl -column "CTL_MACHDEP" "ufs/ffs/ffs_extern.h" "Description" -offset indent .It Sy "Name" Ta Sy "Next level names" Ta Sy "Description" .It Dv CTL_DDB Ta "ddb/db_var.h" Ta "Kernel debugger" .It Dv CTL_DEBUG Ta "sys/sysctl.h" Ta "Debugging" .It Dv CTL_FS Ta "sys/sysctl.h" Ta "File system" .It Dv CTL_HW Ta "sys/sysctl.h" Ta "Generic CPU, I/O" .It Dv CTL_KERN Ta "sys/sysctl.h" Ta "High kernel limits" .It Dv CTL_MACHDEP Ta "sys/sysctl.h" Ta "Machine dependent" .It Dv CTL_NET Ta "sys/socket.h" Ta "Networking" .It Dv CTL_VFS Ta "ufs/ffs/ffs_extern.h" Ta "Virtual file system" .It Dv CTL_VM Ta "uvm/uvm_param.h" Ta "Virtual memory" .El .Pp For example, the following retrieves the maximum number of processes allowed in the system: .Bd -literal -offset indent int mib[2], maxproc; size_t len; mib[0] = CTL_KERN; mib[1] = KERN_MAXPROC; len = sizeof(maxproc); if (sysctl(mib, 2, &maxproc, &len, NULL, 0) == -1) err(1, "sysctl"); .Ed .Ss CTL_DDB Integer information and settable variables are available for the .Dv CTL_DDB level , as described below. More information is also available in .Xr ddb 4 . .Bl -column "Second level name" "integer" "Changeable" -offset indent .It Sy "Second level name" Ta Sy "Type" Ta Sy "Changeable" .It Dv DBCTL_CONSOLE Ta "integer" Ta "yes" .It Dv DBCTL_LOG Ta "integer" Ta "yes" .It Dv DBCTL_MAXLINE Ta "integer" Ta "yes" .It Dv DBCTL_MAXWIDTH Ta "integer" Ta "yes" .It Dv DBCTL_PANIC Ta "integer" Ta "yes" .It Dv DBCTL_RADIX Ta "integer" Ta "yes" .It Dv DBCTL_TABSTOP Ta "integer" Ta "yes" .It Dv DBCTL_TRIGGER Ta "integer" Ta "yes" .El .Bl -tag -width "123456" .It Dv DBCTL_CONSOLE Pq Va ddb.console When this variable is set, an architecture dependent magic key sequence on the console or a debugger button will permit entry into the kernel debugger. When running with a .Xr securelevel 7 greater than 0, this variable may not be raised. .It Dv DBCTL_LOG Pq Va ddb.log When set, ddb output is also logged in the kernel message buffer. .It Dv DBCTL_MAXLINE Pq Va ddb.max_line Determines the number of lines to page in .Xr ddb 4 . This variable is also available as the ddb .Dv $lines variable. .It Dv DBCTL_MAXWIDTH Pq Va ddb.max_width Determines the maximum width of a line in .Xr ddb 4 . This variable is also available as the ddb .Dv $maxwidth variable. .It Dv DBCTL_PANIC Pq Va ddb.panic When this variable is set, system panics may drop into the kernel debugger. When running with a .Xr securelevel 7 greater than 0, this variable may not be raised. .It Dv DBCTL_RADIX Pq Va ddb.radix Determines the default radix or base for non-prefixed numbers entered into .Xr ddb 4 . This variable is also available as the ddb .Dv $radix variable. .It Dv DBCTL_TABSTOP Pq Va ddb.tab_stop_width Width of a tab stop in .Xr ddb 4 . This variable is also available as the ddb .Dv $tabstops variable. .It Dv DBCTL_TRIGGER Pq Va ddb.trigger When .Dv DBCTL_CONSOLE is set, writing to .Dv DBCTL_TRIGGER causes the system to enter .Xr ddb 4 . When running with a .Xr securelevel 7 greater than 0, the process writing to this variable must be running on the console in order to enter .Xr ddb 4 . .El .Ss CTL_DEBUG The debugging variables vary from system to system. A debugging variable may be added or deleted without need to recompile .Fn sysctl to know about it. Each time it runs, .Fn sysctl gets the list of debugging variables from the kernel and displays their current values. The system defines twenty .Li struct ctldebug variables named .Va debug0 through .Va debug19 . They are declared as separate variables so that they can be individually initialized at the location of their associated variable. The loader prevents multiple use of the same variable by issuing errors if a variable is initialized in more than one place. For example, to export the variable .Va dospecialcheck as a debugging variable, the following declaration would be used: .Bd -literal -offset indent int dospecialcheck = 1; struct ctldebug debug5 = { "dospecialcheck", &dospecialcheck }; .Ed .Ss CTL_FS The string and integer information available for the .Dv CTL_FS level is detailed below. The changeable column shows whether a process with appropriate privileges may change the value. .Bl -column "Second level name" "integer" "Changeable" -offset indent .It Sy "Second level name" Ta Sy "Type" Ta Sy "Changeable" .It Dv FS_POSIX_SETUID Ta "integer" Ta "yes" .El .Bl -tag -width "123456" .It Dv FS_POSIX_SETUID Pq Va fx.posix.setuid When this variable is set, ownership changes on a file will cause the .Va S_ISUID and .Va S_ISGID bits to be cleared. When running with a .Xr securelevel 7 greater than 0, this variable may not be changed. .El .Ss CTL_HW The string and integer information available for the .Dv CTL_HW level is detailed below. The changeable column shows whether a process with appropriate privileges may change the value. .Bl -column "Second level name" "integer" "Changeable" -offset indent .It Sy "Second level name" Ta Sy "Type" Ta Sy "Changeable" .It Dv HW_ALLOWPOWERDOWN Ta "integer" Ta "yes" .It Dv HW_BYTEORDER Ta "integer" Ta "no" .It Dv HW_CPUSPEED Ta "integer" Ta "no" .It Dv HW_DISKCOUNT Ta "integer" Ta "no" .It Dv HW_DISKNAMES Ta "string" Ta "no" .It Dv HW_DISKSTATS Ta "struct" Ta "no" .It Dv HW_MACHINE Ta "string" Ta "no" .It Dv HW_MODEL Ta "string" Ta "no" .It Dv HW_NCPU Ta "integer" Ta "no" .It Dv HW_NCPUFOUND Ta "integer" Ta "no" .It Dv HW_PAGESIZE Ta "integer" Ta "no" .It Dv HW_PERFPOLICY Ta "string" Ta "yes" .It Dv HW_PHYSMEM Ta "integer" Ta "no" .It Dv HW_PHYSMEM64 Ta "int64_t" Ta "no" .It Dv HW_PRODUCT Ta "string" Ta "no" .It Dv HW_SENSORS Ta "node" Ta "not applicable" .It Dv HW_SETPERF Ta "integer" Ta "yes" .It Dv HW_USERMEM Ta "integer" Ta "no" .It Dv HW_USERMEM64 Ta "int64_t" Ta "no" .It Dv HW_UUID Ta "string" Ta "no" .It Dv HW_VENDOR Ta "string" Ta "no" .It Dv HW_VERSION Ta "string" Ta "no" .El .Bl -tag -width "123456" .It Dv HW_ALLOWPOWERDOWN Pq Va hw.allowpowerdown Some machines generate an interrupt when the power button is pressed and a driver can catch that interrupt. When this variable is set, such an event will cause the system to perform a regular shutdown and power off the machine. When running with a .Xr securelevel 7 greater than 0, this variable may not be changed. .It Dv HW_BYTEORDER Pq Va hw.byteorder The byteorder (4321 or 1234). .It Dv HW_CPUSPEED Pq Va hw.cpuspeed The current CPU frequency .Pq in MHz . .It Dv HW_DISKCOUNT Pq Va hw.diskcount The number of disks currently attached to the system. .It Dv HW_DISKNAMES Pq Va hw.disknames A comma-separated list of disk names. .It Dv HW_DISKSTATS Pq Va hw.diskstats An array of .Li struct diskstats structures containing disk statistics. .It Dv HW_MACHINE Pq Va hw.machine The machine class. .It Dv HW_MODEL Pq Va hw.model The machine model. .It Dv HW_NCPU Pq Va hw.ncpu The number of CPUs being used. .It Dv HW_NCPUFOUND Pq Va hw.ncpufound The number of CPUs found. .It Dv HW_PAGESIZE Pq Va hw.pagesize The software page size. .It Dv HW_PERFPOLICY Pq Va hw.perfpolicy The performance policy for power management. Can be one of .Dq manual , .Dq auto , or .Dq high . .It Dv HW_PHYSMEM The total physical memory, in bytes. This variable is deprecated; use .Dv HW_PHYSMEM64 instead. .It Dv HW_PHYSMEM64 Pq Va hw.physmem The total physical memory, in bytes. .It Dv HW_PRODUCT Pq Va hw.product The product name of the machine. .It Dv HW_SENSORS Pq Va hw.sensors Third level comprises an array of .Li struct sensordev structures containing information about devices that may attach hardware monitoring sensors. .Pp Third, fourth and fifth levels together comprise an array of .Li struct sensor structures containing snapshot readings of hardware monitoring sensors. In such usage, third level indicates the numerical representation of the sensor device name to which the sensor is attached (a device's xname and number are matched with the help of .Li struct sensordev structure above), fourth level indicates sensor type and fifth level is an ordinal sensor number (unique to the specified sensor type on the specified sensor device). .Pp The .Sy sensordev and .Sy sensor structures and .Sy sensor_type enumeration are defined in .In sys/sensors.h . .It Dv HW_SERIALNO Pq Va hw.serialno The serial number of the machine. .It Dv HW_SETPERF Pq Va hw.setperf Current CPU performance .Pq percentage . It is only modifiable if .Dv HW_PERFPOLICY is set to .Dq manual . .It Dv HW_USERMEM The amount of available non-kernel memory in bytes. This variable is deprecated; use .Dv HW_USERMEM64 instead. .It Dv HW_USERMEM64 Pq Va hw.usermem The amount of available non-kernel memory in bytes. .It Dv HW_UUID Pq Va hw.uuid The universal unique identification number assigned to the machine. .It Dv HW_VENDOR Pq Va hw.vendor The vendor name for this machine. .It Dv HW_VERSION Pq Va hw.version The version or revision of this machine. .El .Ss CTL_KERN The string and integer information available for the .Dv CTL_KERN level is detailed below. The changeable column shows whether a process with appropriate privileges may change the value. The types of data currently available are process information, system vnodes, the open file entries, routing table entries, virtual memory statistics, load average history, and clock rate information. .Bl -column "KERN_PROC_NOBROADCASTKILL" "u_int64_t[CPUSTATES]" "no" -offset indent .It Sy "Second level name" Ta Sy "Type" Ta Sy "Changeable" .It Dv KERN_ALLOWKMEM Ta "integer" Ta "yes" .It Dv KERN_ARGMAX Ta "integer" Ta "no" .It Dv KERN_BOOTTIME Ta "struct timeval" Ta "no" .It Dv KERN_CACHEPCT Ta "integer" Ta "yes" .It Dv KERN_CCPU Ta "integer" Ta "no" .It Dv KERN_CLOCKRATE Ta "struct clockinfo" Ta "no" .It Dv KERN_CONSDEV Ta "dev_t" Ta "no" .It Dv KERN_CPTIME Ta "long[CPUSTATES]" Ta "no" .It Dv KERN_CPTIME2 Ta "u_int64_t[CPUSTATES]" Ta "no" .It Dv KERN_DNSJACKPORT Ta "integer" Ta "yes" .It Dv KERN_DOMAINNAME Ta "string" Ta "yes" .It Dv KERN_FILE Ta "struct kinfo_file" Ta "no" .It Dv KERN_FORKSTAT Ta "struct forkstat" Ta "no" .It Dv KERN_FSCALE Ta "integer" Ta "no" .It Dv KERN_FSYNC Ta "integer" Ta "no" .It Dv KERN_GLOBAL_PTRACE Ta "integer" Ta "yes" .It Dv KERN_HOSTID Ta "integer" Ta "yes" .It Dv KERN_HOSTNAME Ta "string" Ta "yes" .It Dv KERN_INTRCNT Ta "node" Ta "not applicable" .It Dv KERN_JOB_CONTROL Ta "integer" Ta "no" .It Dv KERN_MALLOCSTATS Ta "node" Ta "no" .It Dv KERN_MAXCLUSTERS Ta "integer" Ta "yes" .It Dv KERN_MAXFILES Ta "integer" Ta "yes" .It Dv KERN_MAXLOCKSPERUID Ta "integer" Ta "yes" .It Dv KERN_MAXPARTITIONS Ta "integer" Ta "no" .It Dv KERN_MAXPROC Ta "integer" Ta "yes" .It Dv KERN_MAXTHREAD Ta "integer" Ta "yes" .It Dv KERN_MAXVNODES Ta "integer" Ta "yes" .It Dv KERN_MBSTAT Ta "struct mbstat" Ta "no" .It Dv KERN_MSGBUF Ta "char[]" Ta "no" .It Dv KERN_MSGBUFSIZE Ta "integer" Ta "no" .It Dv KERN_NCHSTATS Ta "struct nchstats" Ta "no" .It Dv KERN_NFILES Ta "integer" Ta "no" .It Dv KERN_NGROUPS Ta "integer" Ta "no" .It Dv KERN_NOSUIDCOREDUMP Ta "integer" Ta "yes" .It Dv KERN_NPROCS Ta "integer" Ta "no" .It Dv KERN_NSELCOLL Ta "integer" Ta "no" .It Dv KERN_NTHREADS Ta "integer" Ta "no" .It Dv KERN_NUMVNODES Ta "integer" Ta "no" .It Dv KERN_OSRELEASE Ta "string" Ta "no" .It Dv KERN_OSREV Ta "integer" Ta "no" .It Dv KERN_OSTYPE Ta "string" Ta "no" .It Dv KERN_OSVERSION Ta "string" Ta "no" .It Dv KERN_POSIX1 Ta "integer" Ta "no" .It Dv KERN_PROC Ta "struct kinfo_proc" Ta "no" .It Dv KERN_PROC_ARGS Ta "node" Ta "not applicable" .It Dv KERN_PROC_CWD Ta "string" Ta "not applicable" .It Dv KERN_PROC_NOBROADCASTKILL Ta "node" Ta "not applicable" .It Dv KERN_PROC_VMMAP Ta "struct kinfo_vmentry" Ta "no" .It Dv KERN_PROF Ta "node" Ta "not applicable" .It Dv KERN_RAWPARTITION Ta "integer" Ta "no" .It Dv KERN_SAVED_IDS Ta "integer" Ta "no" .It Dv KERN_SECURELVL Ta "integer" Ta "raise only" .It Dv KERN_SEMINFO Ta "node" Ta "not applicable" .It Dv KERN_SHMINFO Ta "node" Ta "not applicable" .It Dv KERN_SOMAXCONN Ta "integer" Ta "yes" .It Dv KERN_SOMINCONN Ta "integer" Ta "yes" .It Dv KERN_SPLASSERT Ta "int" Ta "yes" .It Dv KERN_STACKGAPRANDOM Ta "integer" Ta "yes" .It Dv KERN_SYSVIPC_INFO Ta "node" Ta "not applicable" .It Dv KERN_SYSVMSG Ta "integer" Ta "no" .It Dv KERN_SYSVSEM Ta "integer" Ta "no" .It Dv KERN_SYSVSHM Ta "integer" Ta "no" .It Dv KERN_TIMECOUNTER Ta "node" Ta "not applicable" .It Dv KERN_TTY Ta "node" Ta "not applicable" .It Dv KERN_TTYCOUNT Ta "integer" Ta "no" .It Dv KERN_VERSION Ta "string" Ta "no" .It Dv KERN_WATCHDOG Ta "node" Ta "not applicable" .It Dv KERN_WXABORT Ta "integer" Ta "yes" .El .Bl -tag -width "123456" .It Dv KERN_ALLOWKMEM Pq Va kern.allowkmem Allow userland processes access to .Pa /dev/mem and .Pa /dev/kmem . When running with a .Xr securelevel 7 greater than 0, this variable may not be changed. .It Dv KERN_ARGMAX Pq Va kern.argmax The maximum number of bytes allowed among the arguments to .Xr exec 3 . .It Dv KERN_BOOTTIME Pq Va kern.boottime A .Li struct timeval structure is returned. This structure contains the time that the system was booted. .It Dv KERN_CACHEPCT Pq Va kern.bufcachepercent The maximum percentage of physical memory the buffer cache may use; the default is 20%. .It Dv KERN_CCPU Pq Va kern.ccpu The scheduler exponential decay value. .It Dv KERN_CLOCKRATE Pq Va kern.clockrate A .Li struct clockinfo structure is returned. This structure contains the clock, statistics clock and profiling clock frequencies, the number of micro-seconds per hz tick, and the clock skew rate. .It Dv KERN_CONSDEV Pq Va kern.consdev The console device. .It Dv KERN_CPTIME Pq Va kern.cp_time An array of longs of size .Li CPUSTATES is returned, containing statistics about the number of ticks spent by the system in interrupt processing, user processes .Po .Xr nice 1 or normal .Pc , system processing, or idling. .It Dv KERN_CPTIME2 Pq Va kern.cp_time2 Similar to .Dv KERN_CPTIME , but obtains information from only the single CPU specified by the third level name given. .It Dv KERN_DNSJACKPORT Pq Va kern.dnsjackport When non-zero, the localhost port to which all DNS sockets should be redirected. .It Dv KERN_DOMAINNAME Pq Va kern.domainname Get or set the YP domain name. .It Dv KERN_FILE Pq Va kern.file Return the entire file table, or a subset of it. An array of .Li struct kinfo_file structures is returned, whose size depends on the current number of selected files in the system. The third and fourth level names are as follows: .Bl -column "Third level name" "Fourth level is:" -offset indent .It Sy "Third level name" Ta Sy "Fourth level is:" .It Dv KERN_FILE_BYFILE Ta "A file type" .It Dv KERN_FILE_BYPID Ta "A process ID" .It Dv KERN_FILE_BYUID Ta "A user ID" .El .Pp The fifth level name is the size of the .Li struct kinfo_file and the sixth level name is the number of structures to return. .It Dv KERN_FORKSTAT Pq Va kern.forkstat A .Li struct forkstat structure is returned. This structure contains information about the number of .Xr fork 2 , .Xr vfork 2 , and .Xr __tfork 3 system calls as well as kernel thread creations since system startup, and the number of pages of virtual memory involved in each. .It Dv KERN_FSCALE Pq Va kern.fscale The kernel fixed-point scale factor. .It Dv KERN_FSYNC Pq Va kern.fsync Return 1 if the File Synchronisation Option is available on this system, otherwise 0. .It Dv KERN_GLOBAL_PTRACE Pq Va kern.global_ptrace When set to 1, permit .Xr ptrace 2 to attach to any process with the appropriate privileges. When set to 0, processes may only attach to their own descendants. .It Dv KERN_HOSTID Pq Va kern.hostid Get or set the host ID. .It Dv KERN_HOSTNAME Pq Va kern.hostname Get or set the hostname. .It Dv KERN_JOB_CONTROL Pq Va kern.job_control Return 1 if job control is available on this system, otherwise 0. .It Dv KERN_MALLOCSTATS Pq Va kern.malloc Return kernel memory bucket statistics. The third level names are detailed below. There are no changeable values in this branch. .Bl -column "KERN_MALLOC_KMEMNAMES" "string" -offset indent .It Sy "Third level name" Ta Sy "Type" .It Dv KERN_MALLOC_BUCKET Ta "node" .It Dv KERN_MALLOC_BUCKETS Ta "string" .It Dv KERN_MALLOC_KMEMNAMES Ta "string" .It Dv KERN_MALLOC_KMEMSTATS Ta "node" .El .Pp The variables are as follows: .Bl -tag -width "123456" .It Dv KERN_MALLOC_BUCKET. Pq Va kern.malloc.bucket A node containing the statistics for the memory bucket of the specified size (in decimal notation, the number of bytes per bucket element, e.g., 16, 32, 128). Each node returns a .Li struct kmembuckets . .Pp If a value is specified that does not correspond directly to a bucket size, the statistics for the closest larger bucket size will be returned instead. .Pp Note that bucket sizes are typically powers of 2. .It Dv KERN_MALLOC_BUCKETS Pq Va kern.malloc.buckets Return a comma-separated list of the bucket sizes used by the kernel. .It Dv KERN_MALLOC_KMEMNAMES Pq Va kern.malloc.kmemnames Return a comma-separated list of the names of the kernel .Xr malloc 9 types. .It Dv KERN_MALLOC_KMEMSTATS Pq Va kern.malloc.kmemstat A node containing the statistics for the memory types of the specified name. Each node returns a .Li struct kmemstats . .El .It Dv KERN_MAXCLUSTERS Pq Va kern.maxclusters The maximum number of .Xr mbuf 9 clusters that may be allocated. .It Dv KERN_MAXFILES Pq Va kern.maxfiles The maximum number of open files that may be open in the system. .It Dv KERN_MAXLOCKSPERUID Pq Va kerb.maxlocksperuid The maximum number of file locks per user; the default is 1024. .It Dv KERN_MAXPARTITIONS Pq Va kern.maxpartitions The maximum number of partitions allowed per disk. .It Dv KERN_MAXPROC Pq Va kern.maxproc The maximum number of simultaneous processes the system will allow. .It Dv KERN_MAXTHREAD Pq Va kern.maxthread The maximum number of simultaneous threads the system will allow. .It Dv KERN_MAXVNODES Pq Va kern.maxvnodes The maximum number of vnodes available on the system. .It Dv KERN_MBSTAT Pq Va kern.mbstat A .Li struct mbstat structure is returned, containing statistics on .Xr mbuf 9 usage. .It Dv KERN_MSGBUF Pq Va kern.msgbuf Returns a buffer containing kernel log messages; see .Xr dmesg 8 . .It Dv KERN_MSGBUFSIZE Pq Va kern.msgbufsize The size of the kernel message buffer. .It Dv KERN_NCHSTATS Pq Va kern.nchstats A .Li struct nchstats structure is returned. This structure contains information about the filename to .Xr inode 5 mapping cache. .It Dv KERN_NFILES Pq Va kern.nfiles Number of open files. .It Dv KERN_NGROUPS Pq Va kern.ngroups The maximum number of supplemental groups. .It Dv KERN_NOSUIDCOREDUMP Pq Va kern.nosuidcoredump Whether a process may dump core after changing user or group ID: .Bl -column "value" "condition" "current directory" .It Sy "value" Ta Sy "condition" Ta Sy "dump core to" .It 0 Ta "euid == 0" Ta "current directory" .It 1 Ta "never" Ta "" .It 2 Ta "always" Ta Pa "/var/crash" .It 3 Ta "depends" Ta Pa "/var/crash/$programname/" .El .It Dv KERN_NPROCS Pq Va kern.nprocs The number of entries in the kernel process table. .It Dv KERN_NSELCOLL Pq Va kern.nselcoll Number of .Xr select 2 collisions. .It Dv KERN_NTHREADS Pq Va kern.nthreads The number of entries in the kernel thread table. .It Dv KERN_NUMVNODES Pq Va kern.numvnodes Number of vnodes in use. .It Dv KERN_OSRELEASE Pq Va kern.osrelease The system release string. .It Dv KERN_OSREV Pq Va kern.osrevision The system revision number. .It Dv KERN_OSTYPE Pq Va kern.ostype The system type string. .It Dv KERN_OSVERSION Pq Va kern.osversion The kernel build version. .It Dv KERN_POSIX1 Pq Va kern.posix1version The version of ISO/IEC 9945 (POSIX 1003.1) with which the system attempts to comply. .It Dv KERN_PROC Pq Va kern.proc Return the entire process table, or a subset of it. An array of .Li struct kinfo_proc structures is returned, whose size depends on the current number of selected processes in the system. The third and fourth level names are as follows: .Bl -column "KERN_PROC_SESSION" "Fourth level is:" -offset indent .It Sy "Third level name" Ta Sy "Fourth level is:" .It Dv KERN_PROC_ALL Ta "None" .It Dv KERN_PROC_KTHREAD Ta "A kernel thread" .It Dv KERN_PROC_PID Ta "A process ID" .It Dv KERN_PROC_PGRP Ta "A process group" .It Dv KERN_PROC_RUID Ta "A real user ID" .It Dv KERN_PROC_SESSION Ta "A session PID" .It Dv KERN_PROC_TTY Ta "A tty device" .It Dv KERN_PROC_UID Ta "A user ID" .El .Pp The fifth level name is the size of the .Li struct kinfo_proc and the sixth level name is the number of structures to return. .It Dv KERN_PROC_ARGS Pq Va kern.procargs Returns the arguments or environment of a process. The third level name is the PID of the process. The fourth level name is one of: .Bl -column KERN_PROC_NARGV -offset indent .It Dv KERN_PROC_ARGV .It Dv KERN_PROC_ENV .It Dv KERN_PROC_NARGV .It Dv KERN_PROC_NENV .El .Pp .Dv KERN_PROC_NARGV and .Dv KERN_PROC_NENV return the number of elements as an .Vt int in the argv or env array. .Dv KERN_PROC_ARGV returns the argv array and .Dv KERN_PROC_ENV returns the environ array. The buffer pointed to by .Fa oldp is filled with an array of char pointers followed by the strings themselves. The last char pointer is a .Dv NULL pointer. .It Dv KERN_PROC_CWD Pq Va kern.proc_cwd Return the current working directory of a process. The third level name is the target process ID. A NUL-terminated string is returned. .It Dv KERN_PROC_NOBROADCASTKILL Pq Va kern.proc_nobroadcastkill When set, a process will no longer be signaled when sending broadcast signals. The third level name is the target process ID. .It Dv KERN_PROC_VMMAP Pq Va kern.proc_vmmap Return the entire process VM map entries. An array of .Li struct kinfo_vmentry structures is returned, whose size depends on the current number of VM map entries of the selected process. Iteration is possible by setting the base address in the first element of .Li struct kinfo_vmentry . .It Dv KERN_PROF Pq Va kern.profiling Return profiling information about the kernel. If the kernel is not compiled for profiling, attempts to retrieve any of the .Dv KERN_PROF values will fail with .Er EOPNOTSUPP . The third level names for the string and integer profiling information are detailed below. The changeable column shows whether a process with appropriate privileges may change the value. .Bl -column "Third level name" "struct gmonparam" -offset indent .It Sy "Third level name" Ta Sy "Type" Ta Sy "Changeable" .It Dv GPROF_COUNT Ta "u_short[]" Ta "yes" .It Dv GPROF_FROMS Ta "u_short[]" Ta "yes" .It Dv GPROF_GMONPARAM Ta "struct gmonparam" Ta "no" .It Dv GPROF_STATE Ta "integer" Ta "yes" .It Dv GPROF_TOS Ta "struct tostruct" Ta "yes" .El .Pp The variables are as follows: .Bl -tag -width "123456" .It Dv GPROF_COUNT Array of statistical program counter counts. .It Dv GPROF_FROMS Array indexed by program counter of call-from points. .It Dv GPROF_GMONPARAM Structure giving the sizes of the above arrays. .It Dv GPROF_STATE Returns .Dv GMON_PROF_ON or .Dv GMON_PROF_OFF to show that profiling is running or stopped. .It Dv GPROF_TOS Array of .Li struct tostruct describing destination of calls and their counts. .El .It Dv KERN_RAWPARTITION Pq Va kern.rawpartition The raw partition of a disk (a == 0). .It Dv KERN_SAVED_IDS Pq Va kern.saved_ids Returns 1 if saved set-group-ID and saved set-user-ID are available. .It Dv KERN_SECURELVL Pq Va kern.securelevel The system security level. This level may be raised by processes with appropriate privileges. It may only be lowered by process 1. .It Dv KERN_SEMINFO Pq Va kern.seminfo Return the elements of .Li struct seminfo . If the kernel is not compiled with System V style semaphore support, attempts to retrieve any of the .Dv KERN_SEMINFO values will fail with .Er EOPNOTSUPP . The third level names for the elements of .Li struct seminfo are detailed below. The changeable column shows whether a process with appropriate privileges may change the value. .Bl -column "KERN_SEMINFO_SEMMNI" "integer" "Changeable" -offset indent .It Sy "Third level name" Ta Sy "Type" Ta Sy "Changeable" .It Dv KERN_SEMINFO_SEMAEM Ta "integer" Ta "no" .It Dv KERN_SEMINFO_SEMMNI Ta "integer" Ta "yes" .It Dv KERN_SEMINFO_SEMMNS Ta "integer" Ta "yes" .It Dv KERN_SEMINFO_SEMMNU Ta "integer" Ta "yes" .It Dv KERN_SEMINFO_SEMMSL Ta "integer" Ta "yes" .It Dv KERN_SEMINFO_SEMOPM Ta "integer" Ta "yes" .It Dv KERN_SEMINFO_SEMUME Ta "integer" Ta "no" .It Dv KERN_SEMINFO_SEMUSZ Ta "integer" Ta "no" .It Dv KERN_SEMINFO_SEMVMX Ta "integer" Ta "no" .El .Pp The variables are as follows: .Bl -tag -width "123456" .It Dv KERN_SEMINFO_SEMAEM Pq Va kern.seminfo.semaem The adjust on exit maximum value. .It Dv KERN_SEMINFO_SEMMNI Pq Va kern.seminfo.semni The maximum number of semaphore identifiers allowed. .It Dv KERN_SEMINFO_SEMMNS Pq Va kern.seminfo.semmns The maximum number of semaphores allowed in the system. .It Dv KERN_SEMINFO_SEMMNU Pq Va kern.seminfo.semnu The maximum number of semaphore undo structures allowed in the system. .It Dv KERN_SEMINFO_SEMMSL Pq Va kern.seminfo.semmsl The maximum number of semaphores allowed per ID. .It Dv KERN_SEMINFO_SEMOPM Pq Va kern.seminfo.semopm The maximum number of operations per .Xr semop 2 call. .It Dv KERN_SEMINFO_SEMUME Pq Va kern.seminfo.semume The maximum number of undo entries per process. .It Dv KERN_SEMINFO_SEMUSZ Pq Va kern.seminfo.semusz The size (in bytes) of the undo structure. .It Dv KERN_SEMINFO_SEMVMX Pq Va kern.seminfo.semvmx The semaphore maximum value. .El .It Dv KERN_SHMINFO Pq Va kern.shminfo Return the elements of .Li struct shminfo . If the kernel is not compiled with System V style shared memory support, attempts to retrieve any of the .Dv KERN_SHMINFO values will fail with .Er EOPNOTSUPP . The third level names for the elements of .Li struct shminfo are detailed below. The changeable column shows whether a process with appropriate privileges may change the value. .Bl -column "KERN_SHMINFO_SHMMAX" "integer" "Changeable" -offset indent .It Sy "Third level name" Ta Sy "Type" Ta Sy "Changeable" .It Dv KERN_SHMINFO_SHMALL Ta "integer" Ta "yes" .It Dv KERN_SHMINFO_SHMMAX Ta "integer" Ta "yes" .It Dv KERN_SHMINFO_SHMMIN Ta "integer" Ta "yes" .It Dv KERN_SHMINFO_SHMMNI Ta "integer" Ta "yes" .It Dv KERN_SHMINFO_SHMSEG Ta "integer" Ta "yes" .El .Pp The variables are as follows: .Bl -tag -width "123456" .It Dv KERN_SHMINFO_SHMALL Pq Va kern.shminfo.shmall The maximum amount of total shared memory allowed in the system (in pages). .It Dv KERN_SHMINFO_SHMMAX Pq Va kern.shminfo.shmmax The maximum shared memory segment size (in bytes). .It Dv KERN_SHMINFO_SHMMIN Pq Va kern.shminfo.shmmin The minimum shared memory segment size (in bytes). .It Dv KERN_SHMINFO_SHMMNI Pq Va kern.shminfo.shmmni The maximum number of shared memory identifiers in the system. .It Dv KERN_SHMINFO_SHMSEG Pq Va kern.shminfo.shmseg The maximum number of shared memory segments per process. .El .It Dv KERN_SOMAXCONN Pq Va kern.somaxconn Upper bound on the number of half-open connections a process can allow to be associated with a socket, using .Xr listen 2 . The default value is 128. .It Dv KERN_SOMINCONN Pq Va kern.sominconn Lower bound on the number of half-open connections a process can allow to be associated with a socket, using .Xr listen 2 . The default value is 80. .It Dv KERN_SPLASSERT Pq Va kern.splassert Modify the system interrupt priority level. Valid values are: .Pp .Bl -tag -width 3n -offset indent -compact .It 0 Disable error checking. .It 1 Print a message if an error is detected. .It 2 Print a message if an error is detected, and a stack trace if possible. .It 3 The same as 2, but also drop into the kernel debugger. .El .Pp Any other value causes a system panic on errors. See .Xr splassert 9 for more information. .It Dv KERN_STACKGAPRANDOM Pq Va kern.stackgap_random Sets the range of the random value added to the stack pointer on each program execution. The random value is added to make buffer overflow exploitation slightly harder. The bigger the number, the harder it is to brute force this added protection, but it also means bigger waste of memory. .It Li KERN_SYSVIPC_INFO Pq Va kern.sysvipc_info Return System V style IPC configuration and run-time information. The third level name selects the System V style IPC facility. .Bl -column "KERN_SYSVIPC_MSG_INFO" "struct shm_sysctl_info" -offset indent .It Sy "Third level name" Ta Sy "Type" .It Dv KERN_SYSVIPC_MSG_INFO Ta "struct msg_sysctl_info" .It Dv KERN_SYSVIPC_SEM_INFO Ta "struct sem_sysctl_info" .It Dv KERN_SYSVIPC_SHM_INFO Ta "struct shm_sysctl_info" .El .Bl -tag -width "123456" .It Dv KERN_SYSVIPC_MSG_INFO Return information on the System V style message facility. The .Sy msg_sysctl_info structure is defined in .In sys/msg.h . .It Dv KERN_SYSVIPC_SEM_INFO Return information on the System V style semaphore facility. The .Sy sem_sysctl_info structure is defined in .In sys/sem.h . .It Dv KERN_SYSVIPC_SHM_INFO Return information on the System V style shared memory facility. The .Sy shm_sysctl_info structure is defined in .In sys/shm.h . .El .It Dv KERN_SYSVMSG Pq Va kern.sysvmsg Returns 1 if System V style message queue functionality is available on this system, otherwise 0. .It Dv KERN_SYSVSEM Pq Va kern.sysvem Returns 1 if System V style semaphore functionality is available on this system, otherwise 0. .It Dv KERN_SYSVSHM Pq Va kern.sysvshm Returns 1 if System V style shared memory functionality is available on this system, otherwise 0. .It Dv KERN_TIMECOUNTER Pq Va kern.timecounter Return statistics information about the kernel time counter. The third level names information is detailed below. The changeable column shows whether a process with appropriate privileges may change the value. .Bl -column "KERN_TIMECOUNTER_TIMESTEPWARNINGS" "integer" -offset indent .It Sy "Third level name" Ta Sy "Type" Ta Sy "Changeable" .It Dv KERN_TIMECOUNTER_CHOICE Ta "string" Ta "no" .It Dv KERN_TIMECOUNTER_HARDWARE Ta "string" Ta "yes" .It Dv KERN_TIMECOUNTER_TICK Ta "integer" Ta "no" .It Dv KERN_TIMECOUNTER_TIMESTEPWARNINGS Ta "integer" Ta "yes" .El .Pp The variables are as follows: .Bl -tag -width "123456" .It Dv KERN_TIMECOUNTER_CHOICE Pq Va kern.timecounter.choice Get the list of kernel time counter sources and their claimed quality (higher is better). .It Dv KERN_TIMECOUNTER_HARDWARE Pq Va kern.timecounter.hardware Get or set the kernel time counter source by name. .It Dv KERN_TIMECOUNTER_TICK Pq Va kern.timecounter.tick Get the number of times we have reset the kernel time counter information. .It Dv KERN_TIMECOUNTER_TIMESTEPWARNINGS Pq Va kern.timecounter.timestepwarnings Get or set a flag to log a message when the kernel time is stepped. .El .It Dv KERN_TTY Pq Va kern.tty Return statistics information about tty input/output. The third level names information is detailed below. The changeable column shows whether a process with appropriate privileges may change the value. .Bl -column "KERN_TTY_TKRAWCC" "struct itty" "Changeable" -offset indent .It Sy "Third level name" Ta Sy "Type" Ta Sy "Changeable" .It Dv KERN_TTY_INFO Ta "struct itty" Ta "no" .It Dv KERN_TTY_TKCANCC Ta "int64_t" Ta "no" .It Dv KERN_TTY_TKNIN Ta "int64_t" Ta "no" .It Dv KERN_TTY_TKNOUT Ta "int64_t" Ta "no" .It Dv KERN_TTY_TKRAWCC Ta "int64_t" Ta "no" .El .Pp The variables are as follows: .Bl -tag -width "123456" .It Dv KERN_TTY_INFO Pq Va kern.tty.ttyinfo Returns an array of .Li struct itty structures containing tty statistics. .It Dv KERN_TTY_TKCANCC Pq Va kern.tty.tk_cancc Returns the number of input characters in canonical mode. .It Dv KERN_TTY_TKNIN Pq Va kern.tty.tk_nin Returns the number of input characters from a .Xr tty 4 . .It Dv KERN_TTY_TKNOUT Pq Va kern.tty.tk_nout Returns the number of output characters on a .Xr tty 4 . .It Dv KERN_TTY_TKRAWCC Pq Va kern.tty.tk_rawcc Returns the number of input characters in raw mode. .El .It Dv KERN_TTYCOUNT Pq Va kern.ttycount Number of available .Xr tty 4 devices. .It Dv KERN_VERSION Pq Va kern.version The system version string. .It Dv KERN_WATCHDOG Pq Va kern.watchdog Return information on hardware watchdog timers. If the kernel does not support a hardware watchdog timer, attempts to retrieve or set any of the .Dv KERN_WATCHDOG values will fail with .Er EOPNOTSUPP . .Bl -column "KERN_WATCHDOG_PERIOD" "integer" "Changeable" -offset indent .It Sy "Third level name" Ta Sy "Type" Ta Sy "Changeable" .It Dv KERN_WATCHDOG_AUTO Ta "integer" Ta "yes" .It Dv KERN_WATCHDOG_PERIOD Ta "integer" Ta "yes" .El .Pp The variables are as follows: .Bl -tag -width "123456" .It Dv KERN_WATCHDOG_AUTO Pq Va kern.watchdog.auto If set to 1, the kernel refreshes the watchdog timer periodically. If set to 0, a userland process must ensure that the watchdog timer gets refreshed by setting the .Dv KERN_WATCHDOG_PERIOD variable. .It Dv KERN_WATCHDOG_PERIOD Pq Va kern.watchdog.period The period of the watchdog timer in seconds. Set to 0 to disable the watchdog timer. .El .It Dv KERN_WXABORT Pq Va kern.wxabort Generate an abort, rather than returning an error, on W^X violation. .El .Ss CTL_MACHDEP The set of variables defined is architecture dependent. Most architectures define at least the following variables. .Bl -column "Second level name" "dev_t" "Changeable" -offset indent .It Sy "Second level name" Ta Sy "Type" Ta Sy "Changeable" .It Dv CPU_CONSDEV Ta "dev_t" Ta "no" .El .Pp Consult the example file .Pa /etc/examples/sysctl.conf for a non-exhaustive list of .Li machdep variables. .Ss CTL_NET The string and integer information available for the .Dv CTL_NET level is detailed below. The changeable column shows whether a process with appropriate privileges may change the value. .Bl -column "Second level name" "routing messages" "Changeable" -offset indent .It Sy "Second level name" Ta Sy "Type" Ta Sy "Changeable" .It Dv PF_ROUTE Ta "routing messages" Ta "no" .It Dv PF_INET Ta "IPv4 values" Ta "yes" .It Dv PF_INET6 Ta "IPv6 values" Ta "yes" .It Dv PF_KEY Ta "key management" Ta "no" .It Dv PF_MPLS Ta "MPLS values" Ta "yes" .It Dv PF_PIPEX Ta "PIPEX values" Ta "yes" .El .Bl -tag -width "123456" .It Dv PF_ROUTE Return the entire routing table or a subset of it. The data is returned as a sequence of routing messages (see .Xr route 4 for the header file, format, and meaning). The length of each message is contained in the message header. .Pp The third level name is a protocol number, which is currently always 0. The fourth level name is an address family, which may be set to 0 to select all address families. The fifth and sixth level names are as follows: .Bl -column "Fifth level name" "Sixth level is:" -offset indent .It Sy "Fifth level name" Ta Sy "Sixth level is:" .It Dv NET_RT_DUMP Ta "priority" .It Dv NET_RT_FLAGS Ta "rtflags" .It Dv NET_RT_IFLIST Ta "None" .It Dv NET_RT_IFNAMES Ta "None" .It Dv NET_RT_STATS Ta "None" .El .Bl -tag -width "123456" .It Li NET_RT_DUMP If set to 0, show all routes. If set to any number, show all routes with that number priority. If set to a negative number, show routes that do not have the positive priority value. .El .Pp An optional seventh level name can be provided to select the routing table on which to run the operation. If not provided, the table with ID 0 is used. .It Dv PF_INET Get or set various global information about IPv4 .Pq Internet Protocol version 4 . The third level name is the protocol. The fourth level name is the variable name. The currently defined protocols and names are: .Bl -column "Protocol name" "ipsec-expire-acquire" "structure" "Changeable" -offset 2n .It Sy "Protocol name" Ta Sy "Variable name" Ta Sy "Type" Ta Sy "Changeable" .It ah Ta enable Ta integer Ta yes .It bpf Ta bufsize Ta integer Ta yes .It bpf Ta maxbufsize Ta integer Ta yes .It carp Ta allow Ta integer Ta yes .It carp Ta log Ta integer Ta yes .It carp Ta preempt Ta integer Ta yes .It divert Ta recvspace Ta integer Ta yes .It divert Ta sendspace Ta integer Ta yes .It esp Ta enable Ta integer Ta yes .It esp Ta udpencap Ta integer Ta yes .It esp Ta udpencap_port Ta integer Ta yes .It etherip Ta allow Ta integer Ta yes .It gre Ta allow Ta integer Ta yes .It gre Ta wccp Ta integer Ta yes .It icmp Ta bmcastecho Ta integer Ta yes .It icmp Ta errppslimit Ta integer Ta yes .It icmp Ta maskrepl Ta integer Ta yes .It icmp Ta rediraccept Ta integer Ta yes .It icmp Ta redirtimeout Ta integer Ta yes .It icmp Ta stats Ta structure Ta no .It icmp Ta tstamprepl Ta integer Ta yes .It ip Ta arpdown Ta integer Ta yes .It ip Ta arptimeout Ta integer Ta yes .It ip Ta directed-broadcast Ta integer Ta yes .It ip Ta encdebug Ta integer Ta yes .It ip Ta forwarding Ta integer Ta yes .It ip Ta ifq Ta node Ta "N/A" .It ip Ta ipsec-allocs Ta integer Ta yes .It ip Ta ipsec-auth-alg Ta string Ta yes .It ip Ta ipsec-bytes Ta integer Ta yes .It ip Ta ipsec-comp-alg Ta string Ta yes .It ip Ta ipsec-enc-alg Ta string Ta yes .It ip Ta ipsec-expire-acquire Ta integer Ta yes .It ip Ta ipsec-firstuse Ta integer Ta yes .It ip Ta ipsec-invalid-life Ta integer Ta yes .It ip Ta ipsec-pfs Ta integer Ta yes .It ip Ta ipsec-soft-allocs Ta integer Ta yes .It ip Ta ipsec-soft-bytes Ta integer Ta yes .It ip Ta ipsec-soft-firstuse Ta integer Ta yes .It ip Ta ipsec-soft-timeout Ta integer Ta yes .It ip Ta ipsec-timeout Ta integer Ta yes .It ip Ta maxqueue Ta integer Ta yes .It ip Ta mforwarding Ta integer Ta yes .It ip Ta mtudisc Ta integer Ta yes .It ip Ta mtudisctimeout Ta integer Ta yes .It ip Ta multipath Ta integer Ta yes .It ip Ta portfirst Ta integer Ta yes .It ip Ta porthifirst Ta integer Ta yes .It ip Ta porthilast Ta integer Ta yes .It ip Ta portlast Ta integer Ta yes .It ip Ta redirect Ta integer Ta yes .It ip Ta sourceroute Ta integer Ta yes .It ip Ta stats Ta structure Ta no .It ip Ta ttl Ta integer Ta yes .It ipcomp Ta enable Ta integer Ta yes .It ipip Ta allow Ta integer Ta yes .It mobileip Ta allow Ta integer Ta yes .It tcp Ta ackonpush Ta integer Ta yes .It tcp Ta always_keepalive Ta integer Ta yes .It tcp Ta baddynamic Ta array Ta yes .It tcp Ta ecn Ta integer Ta yes .It tcp Ta ident Ta structure Ta no .It tcp Ta keepidle Ta integer Ta yes .It tcp Ta keepinittime Ta integer Ta yes .It tcp Ta keepintvl Ta integer Ta yes .It tcp Ta mssdflt Ta integer Ta yes .It tcp Ta reasslimit Ta integer Ta yes .It tcp Ta rfc1323 Ta integer Ta yes .It tcp Ta rfc3390 Ta integer Ta yes .It tcp Ta rootonly Ta array Ta yes .It tcp Ta rstppslimit Ta integer Ta yes .It tcp Ta sack Ta integer Ta yes .It tcp Ta slowhz Ta integer Ta no .It tcp Ta stats Ta structure Ta no .It tcp Ta synbucketlimit Ta integer Ta yes .It tcp Ta syncachelimit Ta integer Ta yes .It tcp Ta synhashsize Ta integer Ta yes .It tcp Ta synuselimit Ta integer Ta yes .It udp Ta baddynamic Ta array Ta yes .It udp Ta checksum Ta integer Ta yes .It udp Ta recvspace Ta integer Ta yes .It udp Ta rootonly Ta array Ta yes .It udp Ta sendspace Ta integer Ta yes .It udp Ta stats Ta structure Ta no .El .Pp The variables are as follows: .Bl -tag -width "123456" .It Li ah.enable Pq Va net.inet.ah.enable If set to 1, enable the Authentication Header .Pq AH IPsec protocol. Enabled by default. See .Xr ipsec 4 for more information. .It Li bpf.bufsize Pq Va net.bpf.bufsize The initial size of .Xr bpf 4 buffers. .It Li bpf.maxbufsize Pq Va net.bpf.maxbufsize The maximum size a user may request a .Xr bpf 4 buffer to be. .It Li carp.allow Pq Va net.inet.carp.allow If set to 0, incoming .Xr carp 4 packets will not be processed. If set to any other value, processing will occur. Enabled by default. .It Li carp.log Pq Va net.inet.carp.log Controls the verbosity of .Xr carp 4 logging. May be a value between 0 and 7 corresponding with .Xr syslog 3 priorities. The default value is 2. .It Li carp.preempt Pq Va net.inet.carp.preempt If set to 0, .Xr carp 4 will not attempt to become master if it is receiving advertisements from another active master. If set to any other value, carp will become master of the virtual host if it believes it can send advertisements more frequently than the current master. Disabled by default. .It Li divert.recvspace Pq Va net.inet.divert.recvspace Returns the default divert receive buffer size. .It Li divert.sendspace Pq Va net.inet.divert.sendspace Returns the default divert send buffer size. .It Li esp.enable Pq Va net.inet.esp.enable If set to 1, enable the Encapsulating Security Payload .Pq ESP IPsec protocol. Enabled by default. See .Xr ipsec 4 for more information. .It Li esp.udpencap Pq Va net.inet.esp.udpencap If set to 1, enable processing of UDP encapsulated ESP packets. Enabled by default. .It Li esp.udpencap_port Pq Va net.inet.udpencap_port Contains the value of the UDP port that triggers decapsulation for incoming UDP encapsulated ESP packets. The default port is 4500. .It Li etherip.allow Pq Va net.inet.etherip.allow If set to 0, incoming Ethernet-in-IPv4 packets will not be processed. If set to any other value, processing will occur. .It Li gre.allow Pq Va net.inet.gre.allow If set to 0, incoming GRE packets will not be processed. If set to any other value, processing will occur. .It Li gre.wccp Pq Va net.inet.gre.wccp If set to 0, incoming WCCPv1-style GRE packets will not be processed. If set to any other value, and gre.allow allows GRE packet processing, WCCPv1-style GRE packets will be processed. .It Li icmp.bmcastecho Pq Va net.inet.icmp.bmcastecho If set to 1, respond to ICMP echo requests destined for broadcast and multicast addresses. Note, enabling this could open a system to a type of denial of service attack called .Qq smurfing , and is thus not advised. .It Li icmp.errppslimit Pq Va net.inet.icmp.errppslimit This variable specifies the maximum number of outgoing ICMP error messages per second. ICMP error messages exceeding this value are subject to rate limitation and will not go out from the node. A negative value disables rate limitation. .It Li icmp.maskrepl Pq Va kern.inet.icmp.maskrepl Returns 1 if ICMP network mask requests are to be answered. .It Li icmp.rediraccept Pq Va kern.inet.icmp.rediraccept If set to non-zero, the host will accept ICMP redirect packets. Note that routers will never accept ICMP redirect packets, and the variable is meaningful on IP hosts only. .It Li icmp.redirtimeout Pq Va net.inet.icmp.redrttimeout This variable specifies the lifetime of routing entries generated by incoming ICMP redirects. The default timeout is 10 minutes. .It Li icmp.stats Pq Va kern.inet.icmp.stats Returns the ICMP statistics in a struct icmpstat. .It Li icmp.tstamprepl Pq Va net.inet.icmp.tstamprepl If set to 1, reply to ICMP timestamp requests. If set to 0, ignore timestamp requests. .It Li ip.arpdown Pq Va net.inet.ip.arpdown Lifetime of unresolved ARP entries, in seconds. .It Li ip.arptimeout Pq Va net.inet.ip.arptimeout Lifetime of resolved ARP entries, in seconds. .It Li ip.directed-broadcast Pq Va net.inet.ip.directed-broadcast Returns 1 if directed broadcast behavior is enabled for the host. .It Li ip.encdebug Pq Va net.inet.ip.encdebug Returns 1 when error message reporting is enabled for the host. If the kernel has been compiled with the .Dv ENCDEBUG option, then debugging information will also be reported when this variable is set. .It Li ip.forwarding Pq Va net.inet.ip.forwarding If set to 1, then IP forwarding is enabled for the host, indicating the host is acting as a router. If set to 2, then IP forwarding is restricted to traffic that has been IPsec encapsulated or decapsulated by the host. The default value is 0. .It Li ip.ifq Fifth level comprises an array of .Li struct ifqueue structures containing information about IP packet input queue. The fifth level names for the elements of .Li struct ifqueue are detailed below. .Bl -column "Fifth level name" "integer" "Changeable" -offset indent .It Sy "Fifth level name" Ta Sy "Type" Ta Sy "Changeable" .It Dv IFQCTL_DROPS Ta "integer" Ta "no" .It Dv IFQCTL_LEN Ta "integer" Ta "no" .It Dv IFQCTL_MAXLEN Ta "integer" Ta "yes" .El .Pp The variables are as follows: .Pp .Bl -tag -width Ds -compact .It Dv IFQCTL_DROPS Pq Va net.inet.ip.ifq.drops Returns number of packet dropped. .It Dv IFQCTL_LEN Pq Va net.inet.ip.ifq.len Returns the current queue length. .It Dv IFQCTL_MAXLEN Pq Va bet.inet.ip.ifq.maxlen Get or set the maximum number of queue length. .El .It Li ip.ipsec-allocs Pq Va net.inet.ip.ipsec-allocs The number of IPsec flows that can use a security association before it expires. If set to less than or equal to zero, the security association will not expire because of this counter. The default value is 0. .It Li ip.ipsec-auth-alg Pq Va net.inet.ip.ipsec-auth-alg This is the default authentication algorithm the kernel will instruct key management daemons to negotiate when establishing security associations on behalf of the kernel. Such security associations can occur as a result of a process having requested some security level through .Xr setsockopt 2 , or as a result of dynamic VPN entries. Supported values are hmac-md5, hmac-sha1, and hmac-ripemd160. If set to any other value, it is left to the key management daemons to select an authentication algorithm for the security association. The default value is hmac-sha1. .It Li ip.ipsec-bytes Pq Va net.inet.ip.ipsec-bytes The number of bytes that will be processed by a security association before it expires. If set to less than or equal to zero, the security association will not expire because of this counter. The default value is 0. .It Li ip.ipsec-comp-alg Pq Va net.inet.ip.ipsec-comp-alg The compression algorithm to use with an IP Compression Association .Pq IPCA . Possible values are .Dq deflate and .Dq lzs . Note that lzs is only available with .Xr hifn 4 . See .Xr ipsecctl 8 for more information. .It Li ip.ipsec-enc-alg Pq Va net.inet.ip.ipsec-enc-alg This is the default encryption algorithm the kernel will instruct key management daemons to negotiate when establishing security associations on behalf of the kernel. Such security associations can occur as a result of a process having requested some security level through .Xr setsockopt 2 , or as a result of dynamic VPN entries. Supported values are aes, des, 3des, blowfish and cast128. If set to any other value, it is left to the key management daemons to select an encryption algorithm for the security association. The default value is aes. .It Li ip.ipsec-expire-acquire Pq Va net.inet.ip.ipsec-expire-acquire How long the kernel should allow key management to dynamically acquire security associations before re-sending a request. The default value is 30 seconds. .It Li ip.ipsec-firstuse Pq Va net.inet.ip.ipsec-firstuse The number of seconds after a security association is first used before it expires. If set to less than or equal to zero, the security association will not expire because of this timer. The default value is 7200 seconds. .It Li ip.ipsec-invalid-life Pq Va net.inet.ip.ipsec-invalid-life The lifetime of embryonic Security Associations (SAs that key management daemons have reserved but not fully established yet) in seconds. If set to less than or equal to zero, embryonic SAs will not expire. The default value is 60. .It Li ip.ipsec-pfs Pq Va net.inet.ip.ipsec-pfs If set to any non-zero value, the kernel will ask the key management daemons to use Perfect Forward Secrecy when establishing IPsec Security Associations. Perfect Forward Secrecy makes IPsec Security Associations cryptographically distinct from each other, such that breaking the key for one such SA does not compromise any others. Requiring PFS for every security association significantly increases the computational load of .Xr isakmpd 8 exchanges. The default value is 1. .It Li ip.ipsec-soft-allocs Pq Va net.inet.ip.ipsec-soft-allocs The number of IPsec flows that can use a security association before a message is sent by the kernel to key management for renegotiation of the security association. If set to less than or equal to zero, no message is sent to key management. The default value is 0. .It Li ip.ipsec-soft-bytes Pq Va net.inet.ip.ipsec-soft-bytes The number of bytes that will be processed by a security association before a message is sent by the kernel to key management for renegotiation of the security association. If set to less than or equal to zero, no message is sent to key management. The default value is 0. .It Li ip.ipsec-soft-firstuse Pq Va net.inet.ip.ipsec-soft-firstuse The number of seconds after a security association is first used before a message is sent by the kernel to key management for renegotiation of the security association. If set to less than or equal to zero, no message is sent to key management. The default value is 3600 seconds. .It Li ip.ipsec-soft-timeout Pq Va net.inet.ip.ipsec-soft-timeout The number of seconds after a security association is established before a message is sent by the kernel to key management for renegotiation of the security association. If set to less than or equal to zero, no message is sent to key management. The default value is 80000 seconds. .It Li ip.ipsec-timeout Pq Va net.inet.ip.ipsec-timeout The number of seconds after a security association is established before it will expire. If set to less than or equal to zero, the security association will not expire because of this timer. The default value is 86400 seconds. .It Li ip.maxqueue Pq Va net.inet.ip.maxqueue Fragment flood protection. Sets the maximum number of unassembled IP fragments in the fragment queue. .It Li ip.mforwarding Pq Va net.inet.ip.mforwarding If set to 1, then multicast forwarding is enabled for the host. The default is 0. .It Li ip.mtudisc Pq Va net.inet.ip.mtudisc Returns 1 if Path MTU Discovery is enabled. .It Li ip.mtudisctimeout Pq Va net.inet.ip.mtudisctimeout Number of seconds in which a route added by the Path MTU Discovery engine will time out. When the route times out, the Path MTU Discovery engine will attempt to probe a larger path MTU. .It Li ip.multipath Pq Va net.inet.ip.multipath This variable enables multipath routing for IPv4 addresses. If set to 0, only the first route selected will be used for a given destination regardless of how many routes exist in the routing table. .It Li ip.portfirst Pq Va net.inet.ip.portfirst Minimum registered port number for TCP/UDP port allocation. Registered ports can be used by ordinary user processes or programs executed by ordinary users. Cannot be less than 1024 or greater than 49151. Must be less than ip.portlast. .It Li ip.porthifirst Pq Va net.inet.ip.porthifirst Minimum dynamic/private port number for TCP/UDP port allocation. Dynamic/private ports can be used by ordinary user processes or programs executed by ordinary users. Cannot be less than 49152 or greater than 65535. Must be less than ip.porthilast. .It Li ip.porthilast Pq Va net.inet.ip.porthilast Maximum dynamic/private port number for TCP/UDP port allocation. Dynamic/private ports can be used by ordinary user processes or programs executed by ordinary users. Cannot be less than 49152 or greater than 65535. Must be greater than ip.porthifirst. .It Li ip.portlast Pq Va net.inet.ip.portlast Maximum registered port number for TCP/UDP port allocation. Registered ports can be used by ordinary user processes or programs executed by ordinary users. Cannot be less than 1024 or greater than 49151. Must be greater than ip.portfirst. .It Li ip.redirect Pq Va net.inet.ip.redirect Returns 1 when ICMP redirects may be sent by the host. This option is ignored unless the host is routing IP packets, and should normally be enabled on all systems. .It Li ip.sourceroute Pq Va net.inet.ip.sourceroute Returns 1 when forwarding of source-routed packets is enabled for the host. When running with a .Xr securelevel 7 greater than 0, this variable may not be changed. .It Li ip.stats Pq Va net.inet.ip.stats Returns the IP statistics in a struct ipstat. .It Li ip.ttl Pq Va net.inet.ip.ttl The maximum time-to-live (hop count) value for an IP packet sourced by the system. This value applies to normal transport protocols, not to ICMP. .It Li ipcomp.enable Pq Va net.inet.ipcomp.enable Enable the IPComp protocol. See .Xr ipsecctl 8 for more information. .It Li ipip.allow Pq Va net.inet.ipip.allow If set to 0, incoming IP-in-IP packets will not be processed. If set to any other value, processing will occur; furthermore, if set to 2, no checks for spoofing of loopback addresses will be done. This is useful only for debugging purposes, and should never be used in production systems. .It Li mobileip.allow Pq Va net.inet.mobileip.allow If set to 0, incoming Mobile IP encapsulated packets (RFC 2004) will not be processed. If set to any other value, processing will occur. .It Li tcp.ackonpush Pq Va net.inet.tcp.ackonpush Returns 1 if TCP segments with the .Dv TH_PUSH flag set are being acknowledged immediately, otherwise 0. .It Li tcp.baddynamic Pq Va net.inet.tcp.baddynamic An array of .Li in_port_t is returned specifying the bitmask of TCP ports between 512 and 1023 inclusive that should not be allocated dynamically by the kernel (i.e., they must be bound specifically by port number). .It Li tcp.ecn Pq Va net.inet.tcp.ecn Returns 1 if Explicit Congestion Notifications for TCP are enabled. .It Li tcp.ident Pq Va net.inet.tcp.ident A .Li struct tcp_ident_mapping specifying a local and foreign endpoint of a TCP socket is filled in with the effective and real UIDs of the process that owns the socket. If no such socket exists, then the effective and real UID values are both set to \-1. .It Li tcp.keepidle Pq Va net.inet.tcp.keepidle If the socket option .Dv SO_KEEPALIVE has been set on a socket, then this value specifies how much time a connection needs to be idle before keepalives are sent. See also tcp.slowhz. .It Li tcp.keepinittime Pq Va net.inet.tcp.keepinittime Time to keep alive the initial SYN packet of a TCP handshake. .It Li tcp.keepintvl Pq Va net.inet.tcp.keepintvl Time after a keepalive probe is sent until, in the absence of any response, another probe is sent. See also tcp.slowhz. .It Li tcp.always_keepalive Pq Va net.inet.tcp.always_keepalive Act as if the option .Dv SO_KEEPALIVE was set on all TCP sockets. .It Li tcp.mssdflt Pq Va net.inet.tcp.mssdflt The maximum segment size that is used as default for non-local connections. The default value is 512. .It Li tcp.reasslimit Pq Va net.inet.tcp.reasslimit The maximum number of out-of-order TCP segments the system will store for reassembly. .It Li tcp.rfc1323 Pq Va net.inet.tcp.rfc1323 Returns 1 if RFC 1323 extensions to TCP are enabled. .It Li tcp.rfc3390 Pq Va net.inet.tcp.rfc3390 Returns 1 if the TCP Initial Window is increased to 4 * MSS or 4380 bytes, as specified in RFC 3390. Returns 2 if the TCP Initial Window is increased to 10 * MSS or 14600 bytes, as specified in RFC 6928. .It Li tcp.rootonly Pq Va net.inet.tcp.rootonly An array of .Li in_port_t is returned specifying the bitmask of TCP ports that can only be bound by processes with root euid. When running with a .Xr securelevel 7 greater than 0, this variable may not be changed. .It Li tcp.rstppslimit Pq Va net.inet.tcp.rstppslimit This variable specifies the maximum number of outgoing TCP RST packets per second. TCP RST packets exceeding this value are subject to rate limitation and will not go out from the node. A negative value disables rate limitation. .It Li tcp.sack Pq Va net.inet.tcp.sack Returns 1 if RFC 2018 Selective Acknowledgements are enabled. .It Li tcp.slowhz Pq Va net.inet.tcp.slowhz The units for tcp.keepidle and tcp.keepintvl; those variables are in ticks of a clock that ticks tcp.slowhz times per second. (That is, their values must be divided by the tcp.slowhz value to get times in seconds.) .It Li tcp.stats Pq Va net.inet.tcp.stats Returns the TCP statistics in a struct tcpstat. .It Li tcp.synbucketlimit Pq Va net.inet.tcp.synbucketlimit The maximum number of entries allowed per hash bucket in the TCP SYN cache. .It Li tcp.syncachelimit Pq Va net.inet.tcp.syncachelimit The maximum number of entries allowed in the TCP SYN cache. .It Li tcp.synhashsize Pq Va net.inet.tcp.synhashsize The number of buckets in the TCP SYN cache hash array. After the value is set, the actual size changes when the alternative SYN cache becomes empty and both SYN caches are swapped. .It Li tcp.synuselimit Pq Va net.inet.tcp.synuselimit The minimum number of times the hash function for the TCP SYN cache is used before it is reseeded. .It Li udp.baddynamic Pq Va net.inet.udp.baddynamic Analogous to .Li tcp.baddynamic but for UDP sockets. .It Li udp.checksum Pq Va net.inet.udp.checksum Returns 1 when UDP checksums are being computed and checked. Disabling UDP checksums is strongly discouraged. .It Li udp.recvspace Pq Va net.inet.udp.recvspace Returns the default UDP receive buffer size. .It Li udp.rootonly Pq Va net.inet.udp.rootonly Analogous to .Li tcp.rootonly but for UDP sockets. .It Li udp.sendspace Pq Va net.inet.udp.sendspace Returns the default UDP send buffer size. .It Li udp.stats Pq Va net.inet.udp.stats Returns the UDP statistics in a struct udpstat. .El .It Dv PF_INET6 Get or set various global information about IPv6 .Pq Internet Protocol version 6 . The third level name is the protocol. The fourth level name is the variable name. The currently defined protocols and names are: .Bl -column "Protocol name" "multicast_mtudisc" "integer" "yes" -offset indent .It Sy "Protocol name" Ta Sy "Variable name" Ta Sy "Type" Ta Sy "Changeable" .It icmp6 Ta errppslimit Ta integer Ta yes .It icmp6 Ta mtudisc_hiwat Ta integer Ta yes .It icmp6 Ta mtudisc_lowat Ta integer Ta yes .It icmp6 Ta nd6_debug Ta integer Ta yes .It icmp6 Ta nd6_delay Ta integer Ta yes .It icmp6 Ta nd6_maxnudhint Ta integer Ta yes .It icmp6 Ta nd6_mmaxtries Ta integer Ta yes .It icmp6 Ta nd6_umaxtries Ta integer Ta yes .It icmp6 Ta redirtimeout Ta integer Ta yes .It ip6 Ta auto_flowlabel Ta integer Ta yes .It ip6 Ta dad_count Ta integer Ta yes .It ip6 Ta dad_pending Ta integer Ta yes .It ip6 Ta defmcasthlim Ta integer Ta yes .It ip6 Ta forwarding Ta integer Ta yes .It ip6 Ta hdrnestlimit Ta integer Ta yes .It ip6 Ta hlim Ta integer Ta yes .It ip6 Ta ifq Ta node Ta "N/A" .It ip6 Ta log_interval Ta integer Ta yes .It ip6 Ta maxdynroutes Ta integer Ta yes .It ip6 Ta maxfragpackets Ta integer Ta yes .It ip6 Ta maxfrags Ta integer Ta yes .It ip6 Ta mforwarding Ta integer Ta yes .It ip6 Ta mtudisctimeout Ta integer Ta yes .It ip6 Ta multicast_mtudisc Ta integer Ta yes .It ip6 Ta multipath Ta integer Ta yes .It ip6 Ta neighborgcthresh Ta integer Ta yes .It ip6 Ta redirect Ta integer Ta yes .It ip6 Ta use_deprecated Ta integer Ta yes .El .Pp The variables are as follows: .Pp .Bl -tag -width "123456" -compact .It Li icmp6.errppslimit Pq Va net.inet6.icmp6.errppslimit This variable specifies the maximum number of outgoing ICMPv6 error messages per second. ICMPv6 error messages exceeding this value are subject to rate limitation and will not go out from the node. A negative value will disable the rate limitation. .Pp .It Li icmp6.mtudisc_hiwat Pq Va net.inet6.icmp6.mtudisc_hiwat .It Li icmp6.mtudisc_lowat Pq Va net.inet6.icmp6.mtudisc_lowat These variables define the maximum number of routing table entries created due to path MTU discovery .Pq preventing denial-of-service attacks with ICMPv6 too big messages . After IPv6 path MTU discovery happens, path MTU information is kept in the routing table. If the number of routing table entries exceeds this value, the kernel will not attempt to keep the path MTU information. .Li icmp6.mtudisc_hiwat is used when we have verified ICMPv6 too big messages. .Li icmp6.mtudisc_lowat is used when we have unverified ICMPv6 too big messages. Verification is performed by using address/port pairs kept in connected PCBs. A negative value disables the upper limit. .Pp .It Li icmp6.nd6_debug Pq Va net.inet6.icmp6.nd6_debug If set to non-zero, IPv6 neighbor discovery will generate debugging messages. The debug output is useful for diagnosing IPv6 interoperability issues. The flag must be set to 0 for normal operation. .Pp .It Li icmp6.nd6_delay Pq Va net.inet6.icmp6.nd6_delay This variable specifies the .Dv DELAY_FIRST_PROBE_TIME timing constant in IPv6 neighbor discovery specification .Pq RFC 4861 , in seconds. .Pp .It Li icmp6.nd6_maxnudhint Pq Va net.inet6.icmp6.nd6_maxnudhint IPv6 neighbor discovery permits upper layer protocols to supply reachability hints, to avoid unnecessary neighbor discovery exchanges. This variable defines the number of consecutive hints the neighbor discovery layer will take. For example, by setting the variable to 3, neighbor discovery will take a maximum of 3 consecutive hints. After receiving 3 hints, the neighbor discovery layer will instead perform the normal neighbor discovery process. .Pp .It Li icmp6.nd6_mmaxtries Pq Va net.inet6.icmp6.nd6_mmaxtries This variable specifies the .Dv MAX_MULTICAST_SOLICIT constant in IPv6 neighbor discovery specification .Pq RFC 4861 . .Pp .It Li icmp6.nd6_umaxtries Pq Va net.inet6.icmp6.nd6_umaxtries This variable specifies the .Dv MAX_UNICAST_SOLICIT constant in IPv6 neighbor discovery specification .Pq RFC 4861 . .Pp .It Li icmp6.redirtimeout Pq Va net.inet6.icmp6.redirtimeout The variable specifies the lifetime of routing entries generated by incoming ICMPv6 redirects. .Pp .It Li ip6.auto_flowlabel Pq Va net.inet6.ip6.auto_flowlabel On connected transport protocol packets, fill the IPv6 flowlabel field to help intermediate routers identify packet flows. .Pp .It Li ip6.dad_count Pq Va net.inet6.ip6.dad_count This variable configures the number of IPv6 DAD .Pq duplicated address detection probe packets. These packets are generated when IPv6 interfaces are first brought up. .Pp .It Li ip6.dad_pending Pq Va net.inet6.ip6.dad_pending This variable displays the number of pending IPv6 DAD .Pq duplicated address detection before completion. It is used to make sure that DAD is completed before .Xr netstart 8 is executed. .Pp .It Li ip6.defmcasthlim Pq Va net.inet6.ip6.defmcasthlim The default hop limit value for an IPv6 multicast packet sourced by the node. This value applies to all the transport protocols on top of IPv6. Methods for overriding this value are documented in .Xr ip6 4 . .Pp .It Li ip6.forwarding Pq Va net.inet6.ip6.forwarding Returns 1 when IPv6 forwarding is enabled for the node, meaning that the node is acting as a router. Returns 0 when IPv6 forwarding is disabled for the node, meaning that the node is acting as a host. Note that IPv6 defines node behavior for the .Dq router and .Dq host cases quite differently, and changing this variable during operation may cause serious trouble. Hence, this variable should only be set at bootstrap time. .Pp .It Li ip6.hdrnestlimit Pq Va net.inet6.ip6.hdrnestlimit The number of IPv6 extension headers permitted on incoming IPv6 packets. If set to 0, the node will accept as many extension headers as possible. .Pp .It Li ip6.hlim Pq Va net.inet6.ip6.hlim The default hop limit value for an IPv6 unicast packet sourced by the node. This value applies to all the transport protocols on top of IPv6. Methods for overriding this value are documented in .Xr ip6 4 . .Pp .It Li ip6.ifq Pq Va net.inet6.ip6.ifq Fifth level comprises an array of .Li struct ifqueue structures containing information about IPv6 packet input queue. The fifth level names for the elements of .Li struct ifqueue are detailed above in .Li ip.ifq . .Pp .It Li ip6.log_interval Pq Va net.inet6.ip6.log_interval This variable permits adjusting the amount of logs generated by the IPv6 packet forwarding engine. The value indicates the number of seconds of interval which must elapse between log output. .Pp .It Li ip6.maxdynroutes Pq Va net.inet6.ip6.maxdynroutes Maximum number of routes created by redirect. Set to negative to disable. The default value is 4096. .Pp .It Li ip6.maxfragpackets Pq Va net.inet6.ip6.maxfragpackets The maximum number of fragmented packets the node will accept. 0 means that the node will not accept any fragmented packets. \-1 means that the node will accept as many fragmented packets as it receives. The flag is provided basically for avoiding possible DoS attacks. .Pp .It Li ip6.maxfrags Pq Va net.inet6.ip6.maxfrags The maximum number of fragments the node will accept. 0 means that the node will not accept any fragments. \-1 means that the node will accept as many fragments as it receives. The flag is provided basically for avoiding possible DoS attacks. .Pp .It Li ip6.mforwarding Pq Va net.inet6.ip6.mforwarding If set to 1, then multicast forwarding is enabled for the host. The default is 0. .Pp .It Li ip6.multicast_mtudisc Pq Va net.inet6.ip6.multicast_mtudisc This variable controls generation of ICMPv6 Too Big messages when the machine is performing as an IPv6 multicast router. If set to 1, an ICMPv6 Too Big message will be generated for multicast packets which were too big to be forwarded. If set to 0, the ICMPv6 Too Big message will be suppressed. .Pp .It Li ip6.multipath Pq Va net.inet6.ip6.multipath This variable enables multipath routing for IPv6 addresses. If set to 0, only the first route selected will be used for a given destination regardless of how many routes exist in the routing table. .Pp .It Li ip6.mtudisctimeout Pq Va net.inet6.ip6.mtudisctimeout Number of seconds in which a route added by the Path MTU Discovery engine will time out. When the route times out, the Path MTU Discovery engine will attempt to probe a larger path MTU. .Pp .It Li ip6.neighborgcthresh Pq Va net.inet6.ip6.neighborgcthresh Maximum number of entries in neighbor cache. Set to negative to disable. The default value is 2048. .Pp .It Li ip6.redirect Pq Va net.inet6.ip6.redirect Returns 1 when ICMPv6 redirects may be sent by the node. This option is ignored unless the node is routing IP packets, and should normally be enabled on all systems. .Pp .It Li ip6.use_deprecated Pq Va net.inet6.ip6.use_deprecated This variable controls the use of deprecated addresses, specified in RFC 4862 5.5.4. .El .Pp We reuse .Li net.inet.tcp and .Li net.inet.udp for TCP/UDP over IPv6. .It Dv PF_KEY Return .Xr ipsec 4 database dumps. The second level name is .Dv PF_KEY_V2 . The third level name selects the database as follows: .Pp .Bl -tag -width "NET_KEY_SADB_DUMP" -offset indent -compact .It Dv NET_KEY_SADB_DUMP Security Association database (SADB). .It Dv NET_KEY_SPD_DUMP IPsec flow database (SPD). .El .It Dv PF_MPLS Get or set global information about MPLS (Multiprotocol Label Switching). .Bl -column "MPLSCTL_MAXINKLOOP " "integer" "not applicable" -offset indent .It Sy "Third level name" Ta Sy "Type" Ta Sy "Changeable" .It Dv MPLSCTL_DEFTTL Ta integer Ta yes .It Dv MPLSCTL_IFQUEUE Ta node Ta "not applicable" .It Dv MPLSCTL_MAPTTL_IP Ta integer Ta yes .It Dv MPLSCTL_MAPTTL_IP6 Ta integer Ta yes .It Dv MPLSCTL_MAXINKLOOP Ta integer Ta yes .El .Bl -tag -width "123456" .It Dv MPLSCTL_DEFTTL Pq Va net.mpls.ttl Set or get the default TTL value which is used for MPLS (Shim) Header. The default is 255. .It Dv MPLSCTL_IFQUEUE Pq Va net.mpls.ifq Fourth level comprises an array of .Li struct ifqueue structures containing information about MPLS packet input queue. The forth level names for the elements of .Li struct ifqueue are same as described in .Li ip.ifq in the .Dv PF_INET section. .It Dv MPLSCTL_MAPTTL_IP Pq Va net.mpls.mapttl_ip If set to 1 the TTL field is synchronized between the IP header and the MPLS label stack. If set to 0 the IP header TTL is not modified while passing through MPLS and the MPLS label stack is initialized with the .Dv MPLSCTL_DEFTTL . The default is 1. .It Dv MPLSCTL_MAPTTL_IP6 Pq Va net.mpls.mapttl_ip6 If set to 1 the TTL field is synchronized between the IPv6 header and the MPLS label stack. If set to 0 the IPv6 header TTL is not modified while passing through MPLS and the MPLS label stack is initialized with the .Dv MPLSCTL_DEFTTL . The default is 0. .It Dv MPLSCTL_MAXINKLOOP Pq Va net.mpls.maxloop_inkernel Set or get the maxinum number of label stack operations (push, swap, pop) that can be made on a packet. The default is 16. .El .It Dv PF_PIPEX Pq Va net.pipex Get or set global information about PIPEX. .Pp The currently defined variable names are: .Bl -column "Third level name" "integer" "Changeable" -offset indent .It Sy "Third level name" Ta Sy "Type" Ta Sy "Changeable" .It Dv PIPEXCTL_ENABLE Ta integer Ta yes .It Dv PIPEXCTL_INQ Ta node Ta not applicable .It Dv PIPEXCTL_OUTQ Ta node Ta not applicable .El .Bl -tag -width "123456" .It Dv PIPEXCTL_ENABLE If set to 1, enable PIPEX processing. The default is 0. .It Dv PIPEXCTL_INQ Pq Va net.pipex.inq Fourth level comprises an array of .Li struct ifqueue structures containing information about the PIPEX packet input queue. The forth level names for the elements of .Li struct ifqueue are the same as described in .Li ip.ifq in the .Dv PF_INET section. .It Dv PIPEXCTL_OUTQ Pq Va net.pipex.outq Fourth level comprises an array of .Li struct ifqueue structures containing information about PIPEX packet output queue. The forth level names for the elements of .Li struct ifqueue are same as described in .Li ip.ifq in the .Dv PF_INET section. .El .El .Ss CTL_VFS The string and integer information available for the .Dv CTL_VFS level is detailed below. The changeable column shows whether a process with appropriate privileges may change the value. .Bl -column "Second level name" "VFS generic info" "Changeable" -offset indent .It Sy "Second level name" Ta Sy "Type" Ta Sy "Changeable" .It Dv VFS_GENERIC Ta "VFS generic info" Ta "no" .It Dv "filesystem #" Ta "filesystem info" Ta "no" .El .Bl -tag -width "123456" .It Dv VFS_GENERIC This second level identifier requests generic information about the VFS layer. Within it, the following third level identifiers exist: .Bl -column "Third level name" "struct vfsconf" "Changeable" -offset indent .It Sy "Third level name" Ta Sy "Type" Ta Sy "Changeable" .It Dv VFS_CONF Ta "struct vfsconf" Ta "no" .It Dv VFS_MAXTYPENUM Ta "int" Ta "no" .El .It filesystem # After finding the filesystem dependent .Va vfc_typenum using .Dv VFS_GENERIC with .Dv VFS_CONF , it is possible to access filesystem dependent information. .Pp Some filesystems may contain settings. .Bl -tag -width "123" .It FFS .Bl -column "FFS_SD_DIRECT_BLK_PTRS" "integer" "Changeable" -offset indent .It Sy "Third level name" Ta Sy "Type" Ta Sy "Changeable" .It Dv FFS_DIRHASH_DIRSIZE Ta "integer" Ta "yes" .It Dv FFS_DIRHASH_MAXMEM Ta "integer" Ta "yes" .It Dv FFS_DIRHASH_MEM Ta "integer" Ta "no" .It Dv FFS_MAX_SOFTDEPS Ta "integer" Ta "yes" .It Dv FFS_SD_BLK_LIMIT_HIT Ta "integer" Ta "yes" .It Dv FFS_SD_BLK_LIMIT_PUSH Ta "integer" Ta "yes" .It Dv FFS_SD_DIR_ENTRY Ta "integer" Ta "yes" .It Dv FFS_SD_DIRECT_BLK_PTRS Ta "integer" Ta "yes" .It Dv FFS_SD_INDIR_BLK_PTRS Ta "integer" Ta "yes" .It Dv FFS_SD_INO_LIMIT_HIT Ta "integer" Ta "yes" .It Dv FFS_SD_INO_LIMIT_PUSH Ta "integer" Ta "yes" .It Dv FFS_SD_INODE_BITMAP Ta "integer" Ta "yes" .It Dv FFS_SD_SYNC_LIMIT_HIT Ta "integer" Ta "yes" .It Dv FFS_SD_TICKDELAY Ta "integer" Ta "yes" .It Dv FFS_SD_WORKLIST_PUSH Ta "integer" Ta "yes" .El .Bl -tag -width "123456" .It Dv FFS_DIRHASH_DIRSIZE Pq Va vfs.ffs.dirhash_dirsize The minimum size of a directory, in bytes, before it is considered for hashing. .It Dv FFS_DIRHASH_MAXMEM Pq Va vfs.ffs.dirhash_maxmem The maximum amount of memory, in bytes, to be used for storing directory hashes. .It Dv FFS_DIRHASH_MEM Pq Va vfs.ffs.dirhash_mem The amount of memory currently used by all directory hashes. .It Dv FFS_MAX_SOFTDEPS Pq Va vfs.ffs.max_softdeps Maximum strcuctures before slowdowns. .It Dv FFS_SD_BLK_LIMIT_HIT Pq Va vfs.ffs.sd_blk_limit_hit Number of times block slowdown imposed. .It Dv FFS_SD_BLK_LIMIT_PUSH Pq Va vfs.ffs.sd_blk_limit_push Number of times block limit neared. .It Dv FFS_SD_DIR_ENTRY Pq Va vfs.ffs.sd_dir_entry Bufs redirtied as dir entry cannot write. .It Dv FFS_SD_DIRECT_BLK_PTRS Pq Va vfs.ffs.sd_direct_blk_ptrs Bufs redirtied as direct ptrs not written. .It Dv FFS_SD_INDIR_BLK_PTRS Pq Va vfs.ffs.sd_indir_blk_ptrs Bufs redirtied as indirect ptrs not written. .It Dv FFS_SD_INO_LIMIT_HIT Pq Va vfs.ffs.sd_ino_limit_hit Number of times inode limit imposed. .It Dv FFS_SD_INO_LIMIT_PUSH Pq Va vfs.ffs.sd_ino_limit_push Number of times inode limit neared. .It Dv FFS_SD_INODE_BITMAP Pq Va vfs.ffs.sd_inode_bitmap Bufs redirtied as inode bitmap not written. .It Dv FFS_SD_SYNC_LIMIT_HIT Pq Va vfs.ffs.sd_sync_limit_hit Number of synchronous slowdowns imposed. .It Dv FFS_SD_TICKDELAY Pq Va vfs.ffs.sd_tickdelay Ticks to pause during slowdown. .It Dv FFS_SD_WORKLIST_PUSH Pq Va vfs.ffs.sd_worklist_push Number of worklist cleanups. .El .It NFS .Bl -column "Third level name" "struct nfsstats" "Changeable" -offset indent .It Sy "Third level name" Ta Sy "Type" Ta Sy "Changeable" .It Dv NFS_NFSSTATS Ta "struct nfsstats" Ta "yes" .It Dv NFS_NIOTHREADS Ta "int" Ta "yes" .El .Bl -tag -width Ds .It Dv NFS_NIOTHREADS Pq Va vfs.nfs.iothreads The number of I/O kernel threads for NFS clients. The default is 4; the maximum is 20. .El .It FUSE .Bl -column "FUSEFS_POOL_NBPAGES" "Type" "Changeable" -offset indent .It Sy "Third level name" Ta Sy "Type" Ta Sy "Changeable" .It Dv FUSEFS_INFBUFS Ta "int" Ta "no" .It Dv FUSEFS_OPENDEVS Ta "int" Ta "no" .It Dv FUSEFS_POOL_NBPAGES Ta "int" Ta "no" .It Dv FUSEFS_WAITFBUFS Ta "int" Ta "no" .El .Bl -tag -width Ds .It Dv FUSEFS_INFBUFS Pq Va vfs.fuse.fusefs_fbufs_in The number of inbound fusebufs. .It Dv FUSEFS_OPENDEVS Pq Va vfs.fuse.fusefs_open_devices The number of FUSE devices opened. .It Dv FUSEFS_POOL_NBPAGES Pq Va vfs.fuse.fusefs_pool_pages The number of pages used for fusebuf memory. .It Dv FUSEFS_WAITFBUFS Pq Va vfs.fuse.fusefs_fbufs_wait The number of fusebufs waiting for a response. .El .El .El .Ss CTL_VM The string and integer information available for the .Dv CTL_VM level is detailed below. The changeable column shows whether a process with appropriate privileges may change the value. .Bl -column "Second level name" "swap encrypt values" "yes" -offset indent .It Sy "Second level name" Ta Sy "Type" Ta Sy "Changeable" .It Dv VM_ANONMIN Ta "integer" Ta "yes" .It Dv VM_LOADAVG Ta "struct loadavg" Ta "no" .It Dv VM_MAXSLP Ta "integer" Ta "no" .It Dv VM_METER Ta "struct vmtotal" Ta "no" .It Dv VM_NKMEMPAGES Ta "integer" Ta "no" .It Dv VM_PSSTRINGS Ta "struct psstrings" Ta "no" .It Dv VM_SWAPENCRYPT Ta "swap encrypt values" Ta "yes" .It Dv VM_USPACE Ta "integer" Ta "no" .It Dv VM_UVMEXP Ta "struct uvmexp" Ta "no" .It Dv VM_VNODEMIN Ta "integer" Ta "yes" .It Dv VM_VTEXTMIN Ta "integer" Ta "yes" .El .Bl -tag -width "123456" .It Dv VM_ANONMIN Pq Va vm.anonmin Percentage of physical memory available for pages which contain anonymous mapping. .It Dv VM_LOADAVG Pq Va vm.loadavg Return the load average history. The returned data consists of a .Li struct loadavg . .It Dv VM_MAXSLP Pq Va vm.maxslp The time for a process to be blocked before being swappable, in seconds. .It Dv VM_METER Pq Va vm.vmmeter Return the system wide virtual memory statistics. The returned data consists of a .Li struct vmtotal . .It Dv VM_NKMEMPAGES Pq Va vm.nkmempages Number of pages in kmem_map. .It Dv VM_PSSTRINGS Pq Va vm.psstrings Returns the address of the process .Li struct ps_strings . The .Xr ps 1 program uses it to locate the argument and environment strings. .It Dv VM_SWAPENCRYPT Contains statistics about swap encryption. The string and integer information available for the third level is detailed below. .Bl -column "Third level name" "integer" "Changeable" -offset indent .It Sy "Third level name" Ta Sy "Type" Ta Sy "Changeable" .It Dv SWPENC_CREATED Ta "integer" Ta "no" .It Dv SWPENC_DELETED Ta "integer" Ta "no" .It Dv SWPENC_ENABLE Ta "integer" Ta "yes" .El .Bl -tag -width "123456" .It Dv SWPENC_CREATED Pq Va vm.swapencrypt.keyscreated The number of encryption keys that have been randomly created. The swap partition is divided into sections of normally 512KB. Each section has its own encryption key. .It Dv SWPENC_DELETED Pq Va vm.swapencrypt.keysdeleted The number of encryption keys that have been deleted, thus effectively erasing the data that has been encrypted with them. Encryption keys are deleted when their reference counter reaches zero. .It Dv SWPENC_ENABLE Pq Va vm.swapencrypt.enable Set to 1 to enable swap encryption for all processes. A 0 disables swap encryption. Pages still on swap receive a grandfather clause. Turning this option on does not affect legacy swap data already on the disk, but all newly written data will be encrypted. When swap encryption is turned on, automatic .Xr crash 8 dumps are disabled. .El .It Dv VM_USPACE Pq Va vm.uspace The number of bytes allocated for each kernel stack. .It Dv VM_UVMEXP Pq Va vm.uvmexp Contains statistics about the UVM memory management system. .It Dv VM_VNODEMIN Pq Va vm.vnodemin Percentage of physical memory available for pages which contain cached file data. .It Dv VM_VTEXTMIN Pq Va vm.vtextmin Percentage of physical memory available for pages which contain cached executable data. .El .Sh RETURN VALUES If the call to .Fn sysctl is unsuccessful, \-1 is returned and .Va errno is set appropriately. .Sh FILES .Bl -tag -width "uvm/uvmXswapXencrypt.h " -compact .It In sys/sysctl.h top level identifiers and second level kernel and hardware identifiers .It In sys/socket.h second level network identifiers .It In sys/gmon.h third level profiling identifiers .It In uvm/uvm_param.h second level virtual memory identifiers .It In uvm/uvm_swap_encrypt.h third level virtual memory identifiers .It In net/if.h packet input/output queue identifiers .It In net/pipex.h third level PIPEX identifiers .It In netinet/in.h third and fourth level IPv4/v6 identifiers .It In netinet/ip_divert.h fourth level divert identifiers .It In netinet/icmp_var.h fourth level ICMP identifiers .It In netinet/icmp6.h fourth level ICMPv6 identifiers .It In netinet/tcp_var.h fourth level TCP identifiers .It In netinet/udp_var.h fourth level UDP identifiers .It In ddb/db_var.h second level ddb identifiers .It In sys/mount.h second level vfs identifiers .It In miscfs/fuse/fusefs.h third level fusefs identifiers .It In nfs/nfs.h third level NFS identifiers .It In ufs/ffs/ffs_extern.h third level FFS identifiers .It In machine/cpu.h second level CPU identifiers .El .Sh ERRORS The following errors may be reported: .Bl -tag -width Er .It Bq Er EFAULT The buffer .Fa name , .Fa oldp , .Fa newp , or length pointer .Fa oldlenp contains an invalid address. .It Bq Er EINVAL The .Fa name array is less than two or greater than .Dv CTL_MAXNAME . .It Bq Er EINVAL A non-null .Fa newp pointer is given and its specified length in .Fa newlen is too large or too small. .It Bq Er ENOMEM The length pointed to by .Fa oldlenp is too short to hold the requested value. .It Bq Er ENOENT The mib specified does not exist, or exceeds the range that is possible. .It Bq Er ENXIO If the mib is a sparsely populated array, this error may be returned instead. .It Bq Er ENOTDIR The .Fa name array specifies an intermediate rather than terminal name. .It Bq Er EOPNOTSUPP The .Fa name array specifies a value that is unknown. .It Bq Er EPERM An attempt is made to set a read-only value. .It Bq Er EPERM A process without appropriate privileges attempts to set a value. .It Bq Er EPERM An attempt to change a value protected by the current kernel security level is made. .It Bq Er ESRCH No process could be found which corresponds to the given process ID. .El .Sh SEE ALSO .Xr pathconf 2 , .Xr sysconf 3 , .Xr ddb 4 , .Xr sysctl.conf 5 , .Xr securelevel 7 , .Xr sysctl 8 .Sh HISTORY The .Fn sysctl function first appeared in .Bx 4.4 .