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Annotation of src/share/man/man7/sysctl.7, Revision 1.36

1.36    ! jruoho      1: .\"    $NetBSD: sysctl.7,v 1.35 2010/03/23 05:54:34 jruoho Exp $
1.1       pavel       2: .\"
                      3: .\" Copyright (c) 1993
                      4: .\"    The Regents of the University of California.  All rights reserved.
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                      7: .\" modification, are permitted provided that the following conditions
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                     18: .\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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                     30: .\"    @(#)sysctl.3    8.4 (Berkeley) 5/9/95
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1.32      wiz        32: .Dd February 21, 2010
1.1       pavel      33: .Dt SYSCTL 7
                     34: .Os
                     35: .Sh NAME
                     36: .Nm sysctl
                     37: .Nd system information variables
                     38: .Sh DESCRIPTION
                     39: The
                     40: .Xr sysctl 3
                     41: library function and the
                     42: .Xr sysctl 8
                     43: utility are used to get and set values of system variables, maintained
                     44: by the kernel.
                     45: The variables are organized in a tree and identified by a sequence of
                     46: numbers, conventionally separated by dots with the topmost identifier
                     47: at the left side.
                     48: The numbers have corresponding text names.
                     49: The
                     50: .Xr sysctlnametomib 3
                     51: function or the
                     52: .Fl M
                     53: argument to the
                     54: .Xr sysctl 8
                     55: utility can be used to convert the text representation to the
                     56: numeric one.
                     57: .Pp
                     58: The individual sysctl variables are described below, both the textual
                     59: and numeric form where applicable.
                     60: The textual names can be used as argument to the
                     61: .Xr sysctl 8
                     62: utility and in the file
                     63: .Pa /etc/sysctl.conf .
                     64: The numeric names are usually defined as preprocessor constants and
                     65: are intended for use by programs.
                     66: Every such constant expands to one integer, which identifies the
                     67: sysctl variable relative to the upper level of the tree.
                     68: See the
                     69: .Xr sysctl 3
                     70: manual page for programming examples.
                     71: .Sh Top level names
                     72: The top level names are defined with a CTL_ prefix in
1.33      joerg      73: .In sys/sysctl.h ,
1.1       pavel      74: and are as follows.
                     75: The next and subsequent levels down are found in the include files
                     76: listed here, and described in separate sections below.
1.21      joerg      77: .Bl -column security CTL_SECURITY "Next level names" "High kernel limits"
1.1       pavel      78: .It Sy Name    Constant        Next level names        Description
1.21      joerg      79: .It kern       CTL_KERN        sys/sysctl.h    High kernel limits
                     80: .It vm CTL_VM  uvm/uvm_param.h Virtual memory
                     81: .It vfs        CTL_VFS sys/mount.h     Filesystem
                     82: .It net        CTL_NET sys/socket.h    Networking
                     83: .It debug      CTL_DEBUG       sys/sysctl.h    Debugging
                     84: .It hw CTL_HW  sys/sysctl.h    Generic CPU, I/O
                     85: .It machdep    CTL_MACHDEP     sys/sysctl.h    Machine dependent
                     86: .It user       CTL_USER        sys/sysctl.h    User-level
                     87: .It ddb        CTL_DDB sys/sysctl.h    In-kernel debugger
                     88: .It proc       CTL_PROC        sys/sysctl.h    Per-process
                     89: .It vendor     CTL_VENDOR      ?       Vendor specific
                     90: .It emul       CTL_EMUL        sys/sysctl.h    Emulation settings
                     91: .It security   CTL_SECURITY    sys/sysctl.h    Security settings
1.1       pavel      92: .El
                     93: .Sh The debug.* subtree
                     94: The debugging variables vary from system to system.
                     95: A debugging variable may be added or deleted without need to recompile
                     96: .Nm
                     97: to know about it.
                     98: Each time it runs,
                     99: .Nm
                    100: gets the list of debugging variables from the kernel and
                    101: displays their current values.
                    102: The system defines twenty
                    103: .Va ( struct ctldebug )
                    104: variables named
                    105: .Dv debug0
                    106: through
                    107: .Dv debug19 .
                    108: They are declared as separate variables so that they can be
                    109: individually initialized at the location of their associated variable.
                    110: The loader prevents multiple use of the same variable by issuing errors
                    111: if a variable is initialized in more than one place.
                    112: For example, to export the variable
                    113: .Dv dospecialcheck
                    114: as a debugging variable, the following declaration would be used:
                    115: .Bd -literal -offset indent -compact
                    116: int dospecialcheck = 1;
                    117: struct ctldebug debug5 = { "dospecialcheck", \*[Am]dospecialcheck };
                    118: .Ed
                    119: .Pp
                    120: Note that the dynamic implementation of
                    121: .Nm
                    122: currently in use largely makes this particular
                    123: .Nm
                    124: interface obsolete.
                    125: See
                    126: .Xr sysctl 8
                    127: .\" and
                    128: .\" .Xr sysctl 9
                    129: for more information.
                    130: .Sh The vfs.* subtree
                    131: A distinguished second level name,
                    132: .Li vfs.generic ( VFS_GENERIC ) ,
                    133: is used to get general information about all filesystems.
1.26      elad      134: It has the following third level identifiers:
                    135: .Bl -tag -width compact
                    136: .It vfs.generic.maxtypenum ( VFS_MAXTYPENUM )
                    137: The highest valid filesystem type number.
                    138: .It vfs.generic.conf ( VFS_CONF )
                    139: Returns configuration information about the file-system type given as a fourth
                    140: level identifier.
                    141: .El
                    142: .Pp
                    143: The remaining second level identifiers are the file-system names, identified
                    144: by the type number returned by a
1.1       pavel     145: .Xr statvfs 2
                    146: call or from
1.27      wiz       147: .Li vfs.generic.conf .
1.1       pavel     148: The third level identifiers available for each filesystem
                    149: are given in the header file that defines the mount
                    150: argument structure for that filesystem.
                    151: .Sh The hw.* subtree
                    152: The string and integer information available for the
                    153: .Li hw
                    154: level is detailed below.
                    155: The changeable column shows whether a process with appropriate
                    156: privilege may change the value.
1.21      joerg     157: .Bl -column "hw.acpi.supported_states" "integer" "Changeable" -offset indent
1.1       pavel     158: .It Sy Second level name       Type    Changeable
1.15      wiz       159: .It hw.acpi.supported_states   string  no
1.1       pavel     160: .It hw.alignbytes      integer no
                    161: .It hw.byteorder       integer no
                    162: .It hw.cnmagic string  yes
                    163: .It hw.disknames       string  no
                    164: .It hw.diskstats       struct  no
                    165: .It hw.machine string  no
                    166: .It hw.machine_arch    string  no
                    167: .It hw.model   string  no
                    168: .It hw.ncpu    integer no
                    169: .It hw.pagesize        integer no
                    170: .It hw.physmem integer no
                    171: .It hw.physmem64       quad    no
                    172: .It hw.usermem integer no
                    173: .It hw.usermem64       quad    no
                    174: .El
                    175: .Pp
                    176: .Bl -tag -width "123456"
1.30      snj       177: .It Li hw.acpi.supported_states
1.15      wiz       178: List of possible
                    179: .Tn ACPI
                    180: sleep states.
                    181: The list can contain the following values:
                    182: .Bl -tag -width XS1X
                    183: .It S0
                    184: fully running
                    185: .It S1
                    186: power on suspend (CPU and hard disks are off)
                    187: .It S2
                    188: similar to S3, usually not implemented
                    189: .It S3
                    190: suspend-to-RAM
                    191: .It S4
                    192: suspend-to-disk (needs BIOS support)
                    193: .It S5
                    194: power off
                    195: .El
1.1       pavel     196: .It Li hw.alignbytes ( HW_ALIGNBYTES )
                    197: Alignment constraint for all possible data types.
                    198: This shows the value
                    199: .Dv ALIGNBYTES
                    200: in
                    201: .Pa /usr/include/machine/param.h ,
                    202: at the kernel compilation time.
                    203: .It Li hw.byteorder ( HW_BYTEORDER )
                    204: The byteorder (4,321, or 1,234).
                    205: .It Li hw.cnmagic ( HW_CNMAGIC )
                    206: The console magic key sequence.
                    207: .It Li hw.disknames ( HW_DISKNAMES )
                    208: The list of (space separated) disk device names on the system.
                    209: .It Li hw.iostatnames ( HW_IOSTATNAMES )
                    210: A space separated list of devices that will have I/O statistics
                    211: collected on them.
                    212: .It Li hw.iostats ( HW_IOSTATS )
                    213: Return statistical information on the NFS mounts, disk and tape
                    214: devices on the system.
                    215: An array of
                    216: .Va struct io_sysctl
                    217: structures is returned,
                    218: whose size depends on the current number of such objects in the system.
                    219: The third level name is the size of the
                    220: .Va struct io_sysctl .
                    221: The type of object can be determined by examining the
                    222: .Va type
                    223: element of
                    224: .Va struct io_sysctl .
                    225: Which can be
                    226: .Dv IOSTAT_DISK
                    227: (disk drive),
                    228: .Dv IOSTAT_TAPE
                    229: (tape drive), or
                    230: .Dv IOSTAT_NFS
                    231: (NFS mount).
                    232: .It Li hw.machine ( HW_MACHINE )
                    233: The machine class.
                    234: .It Li hw.machine_arch ( HW_MACHINE_ARCH )
                    235: The machine CPU class.
                    236: .It Li hw.model ( HW_MODEL )
                    237: The machine model.
                    238: .It Li hw.ncpu ( HW_NCPU )
                    239: The number of CPUs.
                    240: .It Li hw.pagesize ( HW_PAGESIZE )
                    241: The software page size.
                    242: .It Li hw.physmem ( HW_PHYSMEM )
                    243: The bytes of physical memory as a 32-bit integer.
                    244: .It Li hw.physmem64 ( HW_PHYSMEM64 )
                    245: The bytes of physical memory as a 64-bit integer.
                    246: .It Li hw.usermem ( HW_USERMEM )
                    247: The bytes of non-kernel memory as a 32-bit integer.
                    248: .It Li hw.usermem64 ( HW_USERMEM64 )
                    249: The bytes of non-kernel memory as a 64-bit integer.
                    250: .El
                    251: .Sh The kern.* subtree
                    252: The string and integer information available for the
                    253: .Li kern
                    254: level is detailed below.
                    255: The changeable column shows whether a process with appropriate
                    256: privilege may change the value.
                    257: The types of data currently available are process information,
                    258: system vnodes, the open file entries, routing table entries,
                    259: virtual memory statistics, load average history, and clock rate
                    260: information.
1.21      joerg     261: .Bl -column "kern.posix_reader_writer_locks" "struct kinfo_drivers" "not applicable"
1.1       pavel     262: .It Sy Second level name       Type    Changeable
                    263: .It kern.argmax        integer no
                    264: .It kern.autonicetime  integer yes
                    265: .It kern.autoniceval   integer yes
                    266: .It kern.boottime      struct timeval  no
                    267: .It kern.bufq  node    not applicable
                    268: .It kern.ccpu  integer no
                    269: .It kern.clockrate     struct clockinfo        no
                    270: .It kern.consdev       integer no
1.21      joerg     271: .It kern.cp_id struct  no
                    272: .It kern.cp_time       uint64_t[\|]    no
1.1       pavel     273: .It kern.defcorename   string  yes
                    274: .It kern.domainname    string  yes
                    275: .It kern.drivers       struct kinfo_drivers    no
                    276: .It kern.file  struct file     no
                    277: .It kern.forkfsleep    integer yes
                    278: .It kern.fscale        integer no
                    279: .It kern.fsync integer no
1.21      joerg     280: .It kern.hardclock_ticks       integer no
1.1       pavel     281: .It kern.hostid        integer yes
                    282: .It kern.hostname      string  yes
1.21      joerg     283: .It kern.iov_max       integer no
                    284: .It kern.job_control   integer no
1.1       pavel     285: .It kern.labeloffset   integer no
                    286: .It kern.labelsector   integer no
1.21      joerg     287: .It kern.login_name_max        integer no
1.1       pavel     288: .It kern.logsigexit    integer yes
1.21      joerg     289: .It kern.mapped_files  integer no
1.1       pavel     290: .It kern.maxfiles      integer yes
                    291: .It kern.maxpartitions integer no
                    292: .It kern.maxphys       integer no
                    293: .It kern.maxproc       integer yes
                    294: .It kern.maxptys       integer yes
                    295: .It kern.maxvnodes     integer yes
                    296: .It kern.mbuf  node    not applicable
                    297: .It kern.memlock       integer no
1.21      joerg     298: .It kern.memlock_range integer no
                    299: .It kern.memory_protection     integer no
                    300: .It kern.monotonic_clock       integer no
1.1       pavel     301: .It kern.msgbuf        integer no
                    302: .It kern.msgbufsize    integer no
                    303: .It kern.ngroups       integer no
                    304: .It kern.ntptime       struct ntptimeval       no
                    305: .It kern.osrelease     string  no
                    306: .It kern.osrev integer no
                    307: .It kern.ostype        string  no
                    308: .It kern.pipe  node    not applicable
                    309: .It kern.posix1        integer no
1.21      joerg     310: .It kern.posix_barriers        integer no
                    311: .It kern.posix_reader_writer_locks     integer no
                    312: .It kern.posix_semaphores      integer no
                    313: .It kern.posix_spin_locks      integer no
                    314: .It kern.posix_threads integer no
                    315: .It kern.posix_timers  integer no
1.1       pavel     316: .It kern.proc  struct kinfo_proc       no
                    317: .It kern.proc2 struct kinfo_proc2      no
1.21      joerg     318: .It kern.proc_args     string  no
1.1       pavel     319: .It kern.prof  node    not applicable
                    320: .It kern.rawpartition  integer no
1.21      joerg     321: .It kern.root_device   string  no
                    322: .It kern.root_partition        integer no
                    323: .It kern.rtc_offset    integer yes
                    324: .It kern.saved_ids     integer no
1.1       pavel     325: .It kern.securelevel   integer raise only
1.21      joerg     326: .It kern.synchronized_io       integer no
1.1       pavel     327: .It kern.ipc   node    not applicable
1.19      christos  328: .It kern.timecounter   node    not applicable
1.1       pavel     329: .It kern.timex struct  no
                    330: .It kern.tkstat        node    not applicable
                    331: .It kern.urandom       integer no
                    332: .It kern.version       string  no
                    333: .It kern.vnode struct vnode    no
                    334: .El
                    335: .Bl -tag -width "123456"
                    336: .It Li kern.argmax ( KERN_ARGMAX )
                    337: The maximum bytes of argument to
                    338: .Xr execve 2 .
                    339: .It Li kern.autonicetime ( KERN_AUTONICETIME )
                    340: The number of seconds of CPU-time a non-root process may accumulate before
                    341: having its priority lowered from the default to the value of KERN_AUTONICEVAL.
                    342: If set to 0, automatic lowering of priority is not performed, and if set to \-1
                    343: all non-root processes are immediately lowered.
                    344: .It Li kern.autoniceval ( KERN_AUTONICEVAL )
                    345: The priority assigned for automatically niced processes.
1.23      apb       346: .It Li kern.boothowto
                    347: Flags passed from the boot loader; see
                    348: .Xr reboot 2
                    349: for the meanings of the flags.
1.1       pavel     350: .It Li kern.boottime ( KERN_BOOTTIME )
                    351: A
                    352: .Va struct timeval
                    353: structure is returned.
                    354: This structure contains the time that the system was booted.
                    355: .It Li kern.ccpu ( KERN_CCPU )
                    356: The scheduler exponential decay value.
                    357: .It Li kern.clockrate ( KERN_CLOCKRATE )
                    358: A
                    359: .Va struct clockinfo
                    360: structure is returned.
                    361: This structure contains the clock, statistics clock and profiling clock
                    362: frequencies, the number of micro-seconds per hz tick, and the clock
                    363: skew rate.
1.36    ! jruoho    364: Refer to
        !           365: .Xr hz 9
        !           366: for additional details.
1.1       pavel     367: .It Li kern.consdev ( KERN_CONSDEV )
                    368: Console device.
                    369: .It Li kern.cp_id ( KERN_CP_ID )
                    370: Mapping of CPU number to CPU id.
                    371: .It Li kern.cp_time ( KERN_CP_TIME )
                    372: Returns an array of CPUSTATES uint64_ts.
                    373: This array contains the
                    374: number of clock ticks spent in different CPU states.
                    375: On multi-processor systems, the sum across all CPUs is returned unless
                    376: appropriate space is given for one data set for each CPU.
                    377: Data for a specific CPU can also be obtained by adding the number of the
                    378: CPU at the end of the MIB, enlarging it by one.
                    379: .It Li kern.defcorename ( KERN_DEFCORENAME )
                    380: Default template for the name of core dump files (see also
                    381: .Li proc.pid.corename
                    382: in the per-process variables
                    383: .Li proc.* ,
                    384: and
                    385: .Xr core 5
                    386: for format of this template).
                    387: The default value is
                    388: .Nm %n.core
                    389: and can be changed with the kernel configuration option
                    390: .Cd options DEFCORENAME
                    391: (see
                    392: .Xr options 4
                    393: ).
                    394: .It Li kern.domainname ( KERN_DOMAINNAME )
                    395: Get or set the YP domain name.
                    396: .It Li kern.dump_on_panic ( KERN_DUMP_ON_PANIC )
                    397: Perform a crash dump on system panic.
                    398: .It Li kern.drivers ( KERN_DRIVERS )
                    399: Return an array of
                    400: .Va struct kinfo_drivers
                    401: that contains the name and major device numbers of all the device drivers
                    402: in the current kernel.
                    403: The
                    404: .Va d_name
                    405: field is always a NUL terminated string.
                    406: The
                    407: .Va d_bmajor
                    408: field will be set to \-1 if the driver doesn't have a block device.
                    409: .It Li kern.file ( KERN_FILE )
                    410: Return the entire file table.
                    411: The returned data consists of a single
                    412: .Va struct filelist
                    413: followed by an array of
                    414: .Va struct file ,
                    415: whose size depends on the current number of such objects in the system.
                    416: .It Li kern.forkfsleep ( KERN_FORKFSLEEP )
                    417: If
                    418: .Xr fork 2
                    419: system call fails due to limit on number of processes (either
                    420: the global maxproc limit or user's one), wait for this many
                    421: milliseconds before returning
                    422: .Er EAGAIN
                    423: error to process.
                    424: Useful to keep heavily forking runaway processes in bay.
                    425: Default zero (no sleep).
                    426: Maximum is 20 seconds.
                    427: .It Li kern.fscale ( KERN_FSCALE )
                    428: The kernel fixed-point scale factor.
                    429: .It Li kern.fsync ( KERN_FSYNC )
                    430: Return 1 if the POSIX 1003.1b File Synchronization Option is available
                    431: on this system,
                    432: otherwise 0.
                    433: .It Li kern.hardclock_ticks ( KERN_HARDCLOCK_TICKS )
                    434: Returns the number of
                    435: .Xr hardclock 9
                    436: ticks.
                    437: .It Li kern.hostid ( KERN_HOSTID )
                    438: Get or set the host id.
                    439: .It Li kern.hostname ( KERN_HOSTNAME )
                    440: Get or set the hostname.
                    441: .It Li kern.iov_max ( KERN_IOV_MAX )
                    442: Return the maximum number of
                    443: .Va iovec
                    444: structures that a process has available for use with
                    445: .Xr preadv 2 ,
                    446: .Xr pwritev 2 ,
                    447: .Xr readv 2 ,
                    448: .Xr recvmsg 2 ,
                    449: .Xr sendmsg 2
                    450: and
                    451: .Xr writev 2 .
                    452: .It Li kern.job_control ( KERN_JOB_CONTROL )
                    453: Return 1 if job control is available on this system, otherwise 0.
                    454: .It Li kern.labeloffset ( KERN_LABELOFFSET )
                    455: The offset within the sector specified by KERN_LABELSECTOR of the
                    456: .Xr disklabel 5 .
                    457: .It Li kern.labelsector ( KERN_LABELSECTOR )
                    458: The sector number containing the
                    459: .Xr disklabel 5 .
                    460: .It Li kern.login_name_max ( KERN_LOGIN_NAME_MAX )
                    461: The size of the storage required for a login name, in bytes,
                    462: including the terminating NUL.
                    463: .It Li kern.logsigexit ( KERN_LOGSIGEXIT )
                    464: If this flag is non-zero, the kernel will
                    465: .Xr log 9
                    466: all process exits due to signals which create a
                    467: .Xr core 5
                    468: file, and whether the coredump was created.
                    469: .It Li kern.mapped_files ( KERN_MAPPED_FILES )
                    470: Returns 1 if the POSIX 1003.1b Memory Mapped Files Option is available
                    471: on this system,
                    472: otherwise 0.
                    473: .It Li kern.maxfiles ( KERN_MAXFILES )
                    474: The maximum number of open files that may be open in the system.
                    475: .It Li kern.maxpartitions ( KERN_MAXPARTITIONS )
                    476: The maximum number of partitions allowed per disk.
                    477: .It Li kern.maxphys ( KERN_MAXPHYS )
                    478: Maximum raw I/O transfer size.
                    479: .It Li kern.maxproc ( KERN_MAXPROC )
                    480: The maximum number of simultaneous processes the system will allow.
                    481: .It Li kern.maxptys ( KERN_MAXPTYS )
                    482: The maximum number of pseudo terminals.
                    483: This value can be both raised and lowered, though it cannot
                    484: be set lower than number of currently used ptys.
                    485: See also
                    486: .Xr pty 4 .
                    487: .It Li kern.maxvnodes ( KERN_MAXVNODES )
                    488: The maximum number of vnodes available on the system.
                    489: This can only be raised.
                    490: .It Li kern.mbuf ( KERN_MBUF )
                    491: Return information about the mbuf control variables.
                    492: Mbufs are data structures which store network packets and other data
                    493: structures in the networking code, see
                    494: .Xr mbuf 9 .
                    495: The third level names for the mbuf variables are detailed below.
                    496: The changeable column shows whether a process with appropriate
                    497: privilege may change the value.
1.21      joerg     498: .Bl -column "kern.mbuf.nmbclusters" "integer" "Changeable" -offset indent
1.1       pavel     499: .It Sy Third level name        Type    Changeable
                    500: .\" XXX Changeable? really?
                    501: .It kern.mbuf.mblowat  integer yes
                    502: .It kern.mbuf.mclbytes integer yes
                    503: .It kern.mbuf.mcllowat integer yes
                    504: .It kern.mbuf.msize    integer yes
                    505: .It kern.mbuf.nmbclusters      integer yes
                    506: .El
                    507: .Pp
                    508: The variables are as follows:
                    509: .Bl -tag -width "123456"
                    510: .It Li kern.mbuf.mblowat ( MBUF_MBLOWAT )
                    511: The mbuf low water mark.
                    512: .It Li kern.mbuf.mclbytes ( MBUF_MCLBYTES )
                    513: The mbuf cluster size.
                    514: .It Li kern.mbuf.mcllowat ( MBUF_MCLLOWAT )
                    515: The mbuf cluster low water mark.
                    516: .It Li kern.mbuf.msize ( MBUF_MSIZE )
                    517: The mbuf base size.
                    518: .It Li kern.mbuf.nmbclusters ( MBUF_NMBCLUSTERS )
                    519: The limit on the number of mbuf clusters.
                    520: The variable can only be increased, and only increased on machines with
                    521: direct-mapped pool pages.
                    522: .El
                    523: .It Li kern.memlock ( KERN_MEMLOCK )
                    524: Returns 1 if the POSIX 1003.1b Process Memory Locking Option is available
                    525: on this system,
                    526: otherwise 0.
                    527: .It Li kern.memlock_range ( KERN_MEMLOCK_RANGE )
                    528: Returns 1 if the POSIX 1003.1b Range Memory Locking Option is available
                    529: on this system,
                    530: otherwise 0.
                    531: .It Li kern.memory_protection ( KERN_MEMORY_PROTECTION )
                    532: Returns 1 if the POSIX 1003.1b Memory Protection Option is available
                    533: on this system,
                    534: otherwise 0.
                    535: .It Li kern.monotonic_clock ( KERN_MONOTONIC_CLOCK )
                    536: Returns the standard version the implementation of the POSIX 1003.1b
                    537: Monotonic Clock Option conforms to,
                    538: otherwise 0.
                    539: .It Li kern.msgbuf ( KERN_MSGBUF )
                    540: The kernel message buffer, rotated so that the head of the circular kernel
                    541: message buffer is at the start of the returned data.
                    542: The returned data may contain NUL bytes.
                    543: .It Li kern.msgbufsize ( KERN_MSGBUFSIZE )
                    544: The maximum number of characters that the kernel message buffer can hold.
                    545: .It Li kern.ngroups ( KERN_NGROUPS )
                    546: The maximum number of supplemental groups.
                    547: .It Li kern.ntptime ( KERN_NTPTIME )
                    548: A
                    549: .Va struct ntptimeval
                    550: structure is returned.
                    551: This structure contains data used by the
                    552: .Xr ntpd 8
                    553: program.
                    554: .It Li kern.osrelease ( KERN_OSRELEASE )
                    555: The system release string.
                    556: .It Li kern.osrevision ( KERN_OSREV )
                    557: The system revision string.
                    558: .It Li kern.ostype ( KERN_OSTYPE )
                    559: The system type string.
                    560: .It Li kern.pipe ( KERN_PIPE )
                    561: Pipe settings.
                    562: The third level names for the  integer pipe settings is detailed below.
                    563: The changeable column shows whether a process with appropriate
                    564: privilege may change the value.
1.21      joerg     565: .Bl -column "kern.pipe.maxbigpipes" "integer" "Changeable" -offset indent
1.1       pavel     566: .It Sy Third level name        Type    Changeable
                    567: .It kern.pipe.kvasiz   integer yes
                    568: .It kern.pipe.maxbigpipes      integer yes
                    569: .It kern.pipe.maxkvasz integer yes
                    570: .It kern.pipe.limitkva integer yes
                    571: .It kern.pipe.nbigpipes        integer yes
                    572: .El
                    573: .Pp
                    574: The variables are as follows:
                    575: .Bl -tag -width "123456"
                    576: .It Li kern.pipe.kvasiz ( KERN_PIPE_KVASIZ )
                    577: Amount of kernel memory consumed by pipe buffers.
                    578: .It Li kern.pipe.maxbigpipes ( KERN_PIPE_MAXBIGPIPES )
                    579: Maximum number of "big" pipes.
                    580: .It Li kern.pipe.maxkvasz ( KERN_PIPE_MAXKVASZ )
                    581: Maximum amount of kernel memory to be used for pipes.
                    582: .It Li kern.pipe.limitkva ( KERN_PIPE_LIMITKVA )
                    583: Limit for direct transfers via page loan.
                    584: .It Li kern.pipe.nbigpipes ( KERN_PIPE_NBIGPIPES )
                    585: Number of "big" pipes.
                    586: .El
                    587: .It Li kern.posix1version ( KERN_POSIX1 )
                    588: The version of ISO/IEC 9945 (POSIX 1003.1) with which the system
                    589: attempts to comply.
                    590: .It Li kern.posix_barriers ( KERN_POSIX_BARRIERS )
                    591: The version of
                    592: .St -p1003.1
                    593: and its
                    594: Barriers
                    595: option to which the system attempts to conform,
                    596: otherwise 0.
                    597: .It Li kern.posix_reader_writer_locks ( KERN_POSIX_READER_WRITER_LOCKS )
                    598: The version of
                    599: .St -p1003.1
                    600: and its
                    601: Read-Write Locks
                    602: option to which the system attempts to conform,
                    603: otherwise 0.
                    604: .It Li kern.posix_semaphores ( KERN_POSIX_SEMAPHORES )
                    605: The version of
                    606: .St -p1003.1
                    607: and its
                    608: Semaphores
                    609: option to which the system attempts to conform,
                    610: otherwise 0.
                    611: .It Li kern.posix_spin_locks ( KERN_POSIX_SPIN_LOCKS )
                    612: The version of
                    613: .St -p1003.1
                    614: and its
                    615: Spin Locks
                    616: option to which the system attempts to conform,
                    617: otherwise 0.
                    618: .It Li kern.posix_threads ( KERN_POSIX_THREADS )
                    619: The version of
                    620: .St -p1003.1
                    621: and its
                    622: Threads
                    623: option to which the system attempts to conform,
                    624: otherwise 0.
                    625: .It Li kern.posix_timers ( KERN_POSIX_TIMERS )
                    626: The version of
                    627: .St -p1003.1
                    628: and its
                    629: Timers
                    630: option to which the system attempts to conform,
                    631: otherwise 0.
                    632: .It Li kern.proc ( KERN_PROC )
                    633: Return the entire process table, or a subset of it.
                    634: An array of
                    635: .Va struct kinfo_proc
                    636: structures is returned,
                    637: whose size depends on the current number of such objects in the system.
                    638: The third and fourth level numeric names are as follows:
1.21      joerg     639: .Bl -column "KERN_PROC_SESSION" "Fourth level is:" -offset indent
1.1       pavel     640: .It Sy Third level name        Fourth level is:
1.21      joerg     641: .It KERN_PROC_ALL      None
                    642: .It KERN_PROC_GID      A group ID
                    643: .It KERN_PROC_PID      A process ID
                    644: .It KERN_PROC_PGRP     A process group
                    645: .It KERN_PROC_RGID     A real group ID
                    646: .It KERN_PROC_RUID     A real user ID
                    647: .It KERN_PROC_SESSION  A session ID
                    648: .It KERN_PROC_TTY      A tty device
                    649: .It KERN_PROC_UID      A user ID
1.1       pavel     650: .El
                    651: .It Li kern.proc2 ( KERN_PROC2 )
                    652: As for KERN_PROC, but an array of
                    653: .Va struct kinfo_proc2
                    654: structures are returned.
                    655: The fifth level name is the size of the
                    656: .Va struct kinfo_proc2
                    657: and the sixth level name is the number of structures to return.
                    658: .It Li kern.proc_args ( KERN_PROC_ARGS )
                    659: Return the argv or environment strings (or the number thereof)
                    660: of a process.
                    661: Multiple strings are returned separated by NUL characters.
                    662: The third level name is the process ID.
                    663: The fourth level name is as follows:
1.21      joerg     664: .Bl -column "KERN_PROG_NARGV" "The number of environ strings" -offset indent
                    665: .It KERN_PROC_ARGV     The argv strings
                    666: .It KERN_PROC_ENV      The environ strings
                    667: .It KERN_PROC_NARGV    The number of argv strings
                    668: .It KERN_PROC_NENV     The number of environ strings
1.1       pavel     669: .El
                    670: .It Li kern.profiling ( KERN_PROF )
                    671: Return profiling information about the kernel.
                    672: If the kernel is not compiled for profiling,
                    673: attempts to retrieve any of the KERN_PROF values will
                    674: fail with
                    675: .Er EOPNOTSUPP .
                    676: The third level names for the string and integer profiling information
                    677: is detailed below.
                    678: The changeable column shows whether a process with appropriate
                    679: privilege may change the value.
1.21      joerg     680: .Bl -column "kern.profiling.gmonparam" "struct gmonparam" "Changeable" -offset indent
1.1       pavel     681: .It Sy Third level name        Type    Changeable
                    682: .It kern.profiling.count       u_short[\|]     yes
                    683: .It kern.profiling.froms       u_short[\|]     yes
                    684: .It kern.profiling.gmonparam   struct gmonparam        no
                    685: .It kern.profiling.state       integer yes
                    686: .It kern.profiling.tos struct tostruct yes
                    687: .El
                    688: .Pp
                    689: The variables are as follows:
                    690: .Bl -tag -width "123456"
                    691: .It Li kern.profiling.count ( GPROF_COUNT )
                    692: Array of statistical program counter counts.
                    693: .It Li kern.profiling.froms ( GPROF_FROMS )
                    694: Array indexed by program counter of call-from points.
                    695: .It Li kern.profiling.gmonparams ( GPROF_GMONPARAM )
                    696: Structure giving the sizes of the above arrays.
                    697: .It Li kern.profiling.state ( GPROF_STATE )
                    698: Profiling state.
                    699: If set to GMON_PROF_ON, starts profiling.
                    700: If set to GMON_PROF_OFF, stops profiling.
                    701: .It Li kern.profiling.tos ( GPROF_TOS )
                    702: Array of
                    703: .Va struct tostruct
                    704: describing destination of calls and their counts.
                    705: .El
                    706: .It Li kern.rawpartition ( KERN_RAWPARTITION )
                    707: The raw partition of a disk (a == 0).
                    708: .It Li kern.root_device ( KERN_ROOT_DEVICE )
                    709: The name of the root device (e.g.,
                    710: .Dq wd0 ) .
                    711: .It Li kern.root_partition ( KERN_ROOT_PARTITION )
                    712: The root partition on the root device (a == 0).
                    713: .It Li kern.rtc_offset ( KERN_RTC_OFFSET )
                    714: Return the offset of real time clock from UTC in minutes.
                    715: .It Li kern.saved_ids ( KERN_SAVED_IDS )
                    716: Returns 1 if saved set-group and saved set-user ID is available.
                    717: .It Li kern.sbmax ( KERN_SBMAX )
                    718: Maximum socket buffer size.
                    719: .\" XXX units?
                    720: .It Li kern.securelevel ( KERN_SECURELVL )
1.25      elad      721: See
                    722: .Xr secmodel_securelevel 9 .
1.1       pavel     723: .It Li kern.somaxkva ( KERN_SOMAXKVA )
                    724: Maximum amount of kernel memory to be used for socket buffers.
                    725: .\" XXX units?
                    726: .It Li kern.synchronized_io ( KERN_SYNCHRONIZED_IO )
                    727: Returns 1 if the POSIX 1003.1b Synchronized I/O Option is available
                    728: on this system,
                    729: otherwise 0.
                    730: .It Li kern.ipc ( KERN_SYSVIPC )
1.2       wiz       731: Return information about the SysV IPC parameters.
                    732: The third level names for the ipc variables are detailed below.
1.21      joerg     733: .Bl -column "kern.ipc.shm_use_phys" "integer" "Changeable" -offset indent
                    734: .It Sy Third level name        Type    Changeable
                    735: .It kern.ipc.sysvmsg   integer no
                    736: .It kern.ipc.sysvsem   integer no
                    737: .It kern.ipc.sysvshm   integer no
                    738: .It kern.ipc.sysvipc_info      struct  no
                    739: .It kern.ipc.shmmax    integer yes
                    740: .It kern.ipc.shmmni    integer yes
                    741: .It kern.ipc.shmseg    integer yes
                    742: .It kern.ipc.shmmaxpgs integer yes
                    743: .It kern.ipc.shm_use_phys      integer yes
                    744: .It kern.ipc.msgmni    integer yes
                    745: .It kern.ipc.msgseg    integer yes
                    746: .It kern.ipc.semmni    integer yes
                    747: .It kern.ipc.semmns    integer yes
                    748: .It kern.ipc.semmnu    integer yes
1.1       pavel     749: .El
                    750: .Bl -tag -width "123456"
                    751: .It Li kern.ipc.sysvmsg ( KERN_SYSVIPC_MSG )
                    752: Returns 1 if System V style message queue functionality is available
                    753: on this system,
                    754: otherwise 0.
                    755: .It Li kern.ipc.sysvsem ( KERN_SYSVIPC_SEM )
                    756: Returns 1 if System V style semaphore functionality is available
                    757: on this system,
                    758: otherwise 0.
                    759: .It Li kern.ipc.sysvshm ( KERN_SYSVIPC_SHM )
                    760: Returns 1 if System V style share memory functionality is available
                    761: on this system,
                    762: otherwise 0.
                    763: .It Li kern.ipc.sysvipc_info ( KERN_SYSVIPC_INFO )
                    764: Return System V style IPC configuration and run-time information.
                    765: The fourth level name selects the System V style IPC facility.
1.21      joerg     766: .Bl -column "KERN_SYSVIPC_MSG_INFO" "struct shm_sysctl_info" -offset indent
1.1       pavel     767: .It Sy Fourth level name       Type
1.21      joerg     768: .It KERN_SYSVIPC_MSG_INFO      struct msg_sysctl_info
                    769: .It KERN_SYSVIPC_SEM_INFO      struct sem_sysctl_info
                    770: .It KERN_SYSVIPC_SHM_INFO      struct shm_sysctl_info
1.1       pavel     771: .El
                    772: .Pp
                    773: .Bl -tag -width "123456"
                    774: .It Li KERN_SYSVIPC_MSG_INFO
                    775: Return information on the System V style message facility.
                    776: The
                    777: .Sy msg_sysctl_info
                    778: structure is defined in
1.33      joerg     779: .In sys/msg.h .
1.1       pavel     780: .It Li KERN_SYSVIPC_SEM_INFO
                    781: Return information on the System V style semaphore facility.
                    782: The
                    783: .Sy sem_sysctl_info
                    784: structure is defined in
1.33      joerg     785: .In sys/sem.h .
1.1       pavel     786: .It Li KERN_SYSVIPC_SHM_INFO
                    787: Return information on the System V style shared memory facility.
                    788: The
                    789: .Sy shm_sysctl_info
                    790: structure is defined in
1.33      joerg     791: .In sys/shm.h .
1.1       pavel     792: .El
                    793: .It Li kern.ipc.shmmax ( KERN_SYSVIPC_SHMMAX )
                    794: Max shared memory segment size in bytes.
                    795: .It Li kern.ipc.shmmni ( KERN_SYSVIPC_SHMMNI )
                    796: Max number of shared memory identifiers.
                    797: .It Li kern.ipc.shmseg ( KERN_SYSVIPC_SHMSEG )
                    798: Max shared memory segments per process.
                    799: .It Li kern.ipc.shmmaxpgs ( KERN_SYSVIPC_SHMMAXPGS )
                    800: Max amount of shared memory in pages.
                    801: .It Li kern.ipc.shm_use_phys ( KERN_SYSVIPC_SHMUSEPHYS )
1.2       wiz       802: Locking of shared memory in physical memory.
1.3       wiz       803: If 0, memory can be swapped
1.1       pavel     804: out, otherwise it will be locked in physical memory.
1.16      rmind     805: .It Li kern.ipc.msgmni
                    806: Max number of message queue identifiers.
                    807: .It Li kern.ipc.msgseg
                    808: Max number of number of message segments.
                    809: .It Li kern.ipc.semmni
                    810: Max number of number of semaphore identifiers.
                    811: .It Li kern.ipc.semmns
                    812: Max number of number of semaphores in system.
                    813: .It Li kern.ipc.semmnu
                    814: Max number of undo structures in system.
1.1       pavel     815: .El
1.19      christos  816: .It Li kern.timecounter ( dynamic )
                    817: Display and control the timecounter source of the system.
1.21      joerg     818: .Bl -column "kern.timecounter.timestepwarnings" "integer" "Changeable" -offset indent
1.19      christos  819: .It Sy Third level name        Type    Changeable
                    820: .It kern.timecounter.choice    string  no
                    821: .It kern.timecounter.hardware  string  yes
                    822: .It kern.timecounter.timestepwarnings  integer yes
                    823: .El
                    824: .Pp
                    825: The variables are as follows:
                    826: .Bl -tag -width "123456"
                    827: .It Li kern.timecounter.choice ( dynamic )
                    828: The list of available timecounters with their quality and frequency.
                    829: .It Li kern.timecounter.hardware ( dynamic )
                    830: The currently selected timecounter source.
                    831: .It Li kern.timecounter.timestepwarnings ( dynamic )
                    832: If non-zero display a message each time the time is stepped.
                    833: .El
1.1       pavel     834: .It Li kern.timex ( KERN_TIMEX )
                    835: Not available.
                    836: .It Li kern.tkstat ( KERN_TKSTAT )
                    837: Return information about the number of characters sent and received
                    838: on ttys.
                    839: The third level names for the tty statistic variables are detailed below.
                    840: The changeable column shows whether a process
                    841: with appropriate privilege may change the value.
1.21      joerg     842: .Bl -column "kern.tkstat.cancc" "quad" "Changeable" -offset indent
1.1       pavel     843: .It Sy Third level name        Type    Changeable
                    844: .It kern.tkstat.cancc  quad    no
                    845: .It kern.tkstat.nin    quad    no
                    846: .It kern.tkstat.nout   quad    no
                    847: .It kern.tkstat.rawcc  quad    no
                    848: .El
                    849: .Pp
                    850: The variables are as follows:
                    851: .Bl -tag -width "123456"
                    852: .It Li kern.tkstat.cancc ( KERN_TKSTAT_CANCC )
                    853: The number of canonical input characters.
                    854: .It Li kern.tkstat.nin ( KERN_TKSTAT_NIN )
                    855: The total number of input characters.
                    856: .It Li kern.tkstat.nout ( KERN_TKSTAT_NOUT )
                    857: The total number of output characters.
                    858: .It Li kern.tkstat.rawcc ( KERN_TKSTAT_RAWCC )
                    859: The number of raw input characters.
                    860: .El
                    861: .It Li kern.urandom ( KERN_URND )
                    862: Random integer value.
                    863: .It Li kern.veriexec
                    864: Tunings for Verixec.
                    865: .Bl -tag -width "123456"
                    866: .It Li kern.veriexec.algorithms
                    867: Returns a string with the supported algorithms in Veriexec.
                    868: .It Li kern.veriexec.count
                    869: Sub-nodes are added to this node as new mounts are monitored by Veriexec.
                    870: Each mount will be under its own
                    871: .No tableN
                    872: node.
                    873: Under each node there will be three variables, indicating the mount
                    874: point, the file-system type, and the number of entries.
                    875: .It Li kern.veriexec.strict
                    876: Controls the strict level of Veriexec.
                    877: See
                    878: .Xr security 8
                    879: for more information on each level's implications.
                    880: .It Li kern.veriexec.verbose
                    881: Controls the verbosity level of Veriexec.
                    882: If 0, only the minimal
                    883: indication required will be given about what's happening - fingerprint
                    884: mismatches, removal of entries from the tables, modification of a
                    885: fingerprinted file.
                    886: If 1, more messages will be printed (ie., when a file with a valid
                    887: fingerprint is accessed).
                    888: Verbose level 2 is debug mode.
                    889: .El
                    890: .It Li kern.version ( KERN_VERSION )
                    891: The system version string.
                    892: .It Li kern.vnode ( KERN_VNODE )
                    893: Return the entire vnode table.
                    894: Note, the vnode table is not necessarily a consistent snapshot of
                    895: the system.
                    896: The returned data consists of an array whose size depends on the
                    897: current number of such objects in the system.
                    898: Each element of the array contains the kernel address of a vnode
                    899: .Va struct vnode *
                    900: followed by the vnode itself
                    901: .Va struct vnode .
                    902: .It Li kern.coredump.setid
                    903: Settings related to set-id processes coredumps.
                    904: By default, set-id processes do not dump core in situations where
                    905: other processes would.
                    906: The settings in this node allows an administrator to change this
                    907: behavior.
                    908: .Pp
                    909: .Bl -tag -width "123456"
                    910: .It Li kern.coredump.setid.dump
                    911: If non-zero, set-id processes will dump core.
                    912: .It Li kern.coredump.setid.group
                    913: The group-id for the set-id processes' coredump.
                    914: .It Li kern.coredump.setid.mode
                    915: The mode for the set-id processes' coredump.
                    916: See
                    917: .Xr chmod 1 .
                    918: .It Li kern.coredump.setid.owner
                    919: The user-id that will be used as the owner of the set-id processes'
                    920: coredump.
                    921: .It Li kern.coredump.setid.path
                    922: The path to which set-id processes' coredumps will be saved to.
                    923: Same syntax as kern.defcorename.
                    924: .El
                    925: .\" XXX kern.lwp
                    926: .El
                    927: .Sh The machdep.* subtree
                    928: The set of variables defined is architecture dependent.
                    929: Most architectures define at least the following variables.
1.21      joerg     930: .Bl -column "Second level name" "Type" "Changeable" -offset indent
1.1       pavel     931: .It Sy Second level name       Type    Changeable
                    932: .It Li CPU_CONSDEV     dev_t   no
                    933: .El
                    934: .Sh The net.* subtree
                    935: The string and integer information available for the
                    936: .Li net
                    937: level is detailed below.
                    938: The changeable column shows whether a process with appropriate
                    939: privilege may change the value.
                    940: The second and third levels are typically the protocol family and
                    941: protocol number, though this is not always the case.
1.21      joerg     942: .Bl -column "Second level name" "IPsec key management values" "Changeable" -offset indent
1.1       pavel     943: .It Sy Second level name       Type    Changeable
                    944: .It net.route  routing messages        no
                    945: .It net.inet   IPv4 values     yes
                    946: .It net.inet6  IPv6 values     yes
                    947: .It net.key    IPsec key management values     yes
                    948: .El
                    949: .Pp
                    950: .Bl -tag -width "123456"
                    951: .It Li net.route ( PF_ROUTE )
                    952: .\" XXX really?
                    953: Return the entire routing table or a subset of it.
                    954: The data is returned as a sequence of routing messages (see
                    955: .Xr route 4
                    956: for the header file, format and meaning).
                    957: The length of each message is contained in the message header.
                    958: .Pp
                    959: The third level name is a protocol number, which is currently always 0.
                    960: The fourth level name is an address family, which may be set to 0 to
                    961: select all address families.
                    962: The fifth and sixth level names are as follows:
1.21      joerg     963: .Bl -column "Fifth level name" "Sixth level is:" -offset indent
1.1       pavel     964: .It Sy Fifth level name        Sixth level is:
1.21      joerg     965: .It NET_RT_FLAGS       rtflags
                    966: .It NET_RT_DUMP        None
                    967: .It NET_RT_IFLIST      None
1.1       pavel     968: .El
                    969: .It Li net.inet ( PF_INET )
                    970: Get or set various global information about the IPv4
                    971: .Pq Internet Protocol version 4 .
                    972: The third level name is the protocol.
                    973: The fourth level name is the variable name.
                    974: The currently defined protocols and names are:
1.21      joerg     975: .Bl -column "Protocol name" "sack.globalmaxholes" "integer" "Changeable" -offset 4n
1.1       pavel     976: .It Sy Protocol name   Variable name   Type    Changeable
                    977: .It arp        down    integer yes
                    978: .It arp        keep    integer yes
                    979: .It arp        prune   integer yes
                    980: .It arp        refresh integer yes
                    981: .It carp       allow   integer yes
                    982: .It carp       preempt integer yes
                    983: .It carp       log     integer yes
                    984: .It carp       arpbalance      integer yes
                    985: .It icmp       errppslimit     integer yes
                    986: .It icmp       maskrepl        integer yes
                    987: .It icmp       rediraccept     integer yes
                    988: .It icmp       redirtimeout    integer yes
1.28      christos  989: .It icmp       bmcastecho      integer yes
1.1       pavel     990: .It ip allowsrcrt      integer yes
                    991: .It ip anonportmax     integer yes
                    992: .It ip anonportmin     integer yes
                    993: .It ip checkinterface  integer yes
                    994: .It ip directed-broadcast      integer yes
                    995: .It ip do_loopback_cksum       integer yes
                    996: .It ip forwarding      integer yes
                    997: .It ip forwsrcrt       integer yes
                    998: .It ip gifttl  integer yes
                    999: .It ip grettl  integer yes
1.8       liamjfoy 1000: .It ip hashsize        integer yes
1.1       pavel    1001: .It ip hostzerobroadcast       integer yes
                   1002: .It ip lowportmin      integer yes
                   1003: .It ip lowportmax      integer yes
                   1004: .It ip maxflows        integer yes
                   1005: .It ip maxfragpackets  integer yes
                   1006: .It ip mtudisc integer yes
                   1007: .It ip mtudisctimeout  integer yes
                   1008: .It ip random_id       integer yes
                   1009: .It ip redirect        integer yes
                   1010: .It ip subnetsarelocal integer yes
                   1011: .It ip ttl     integer yes
                   1012: .It tcp        rfc1323 integer yes
                   1013: .It tcp        sendspace       integer yes
                   1014: .It tcp        recvspace       integer yes
                   1015: .It tcp        mssdflt integer yes
                   1016: .It tcp        syn_cache_limit integer yes
                   1017: .It tcp        syn_bucket_limit        integer yes
                   1018: .It tcp        syn_cache_interval      integer yes
                   1019: .It tcp        init_win        integer yes
                   1020: .It tcp        init_win_local  integer yes
                   1021: .It tcp        mss_ifmtu       integer yes
                   1022: .It tcp        win_scale       integer yes
                   1023: .It tcp        timestamps      integer yes
                   1024: .It tcp        compat_42       integer yes
                   1025: .It tcp        cwm     integer yes
                   1026: .It tcp        cwm_burstsize   integer yes
                   1027: .It tcp        ack_on_push     integer yes
                   1028: .It tcp        keepidle        integer yes
                   1029: .It tcp        keepintvl       integer yes
                   1030: .It tcp        keepcnt integer yes
                   1031: .It tcp        slowhz  integer no
1.12      christos 1032: .It tcp        keepinit        integer yes
1.1       pavel    1033: .It tcp        log_refused     integer yes
                   1034: .It tcp        rstppslimit     integer yes
                   1035: .It tcp        ident   struct  no
1.13      christos 1036: .It tcp        drop    struct  no
1.1       pavel    1037: .It tcp        sack.enable     integer yes
                   1038: .It tcp        sack.globalholes        integer no
                   1039: .It tcp        sack.globalmaxholes     integer yes
                   1040: .It tcp        sack.maxholes   integer yes
                   1041: .It tcp        ecn.enable      integer yes
                   1042: .It tcp        ecn.maxretries  integer yes
                   1043: .It tcp        congctl.selected        string  yes
                   1044: .It tcp        congctl.available       string  yes
                   1045: .It tcp        abc.enable      integer yes
                   1046: .It tcp        abc.aggressive  integer yes
                   1047: .It udp        checksum        integer yes
                   1048: .It udp        do_loopback_cksum       integer yes
                   1049: .It udp        recvspace       integer yes
                   1050: .It udp        sendspace       integer yes
                   1051: .El
                   1052: .Pp
                   1053: The variables are as follows:
                   1054: .Bl -tag -width "123456"
                   1055: .It Li arp.down
                   1056: Failed ARP entry lifetime.
                   1057: .It Li arp.keep
                   1058: Valid ARP entry lifetime.
                   1059: .It Li arp.prune
                   1060: ARP cache pruning interval.
                   1061: .It Li arp.refresh
                   1062: ARP entry refresh interval.
                   1063: .It Li carp.allow
                   1064: If set to 0, incoming
                   1065: .Xr carp 4
                   1066: packets will not be processed.
                   1067: If set to any other value, processing will occur.
                   1068: Enabled by default.
                   1069: .It Li carp.arpbalance
                   1070: If set to any value other than 0, the ARP balancing functionality of
                   1071: .Xr carp 4
                   1072: is enabled.
                   1073: When ARP requests are received for an IP address which is part of any virtual
                   1074: host, carp will hash the source IP in the ARP request to select one of the
                   1075: virtual hosts from the set of all the virtual hosts which have that IP address.
                   1076: The master of that host will respond with the correct virtual MAC address.
                   1077: Disabled by default.
                   1078: .It Li carp.log
                   1079: If set to any value other than 0,
                   1080: .Xr carp 4
                   1081: will log errors.
                   1082: Disabled by default.
                   1083: .It Li carp.preempt
                   1084: If set to 0,
                   1085: .Xr carp 4
                   1086: will not attempt to become master if it is receiving advertisements from
                   1087: another active master.
                   1088: If set to any other value, carp will become master of the virtual host if it
                   1089: believes it can send advertisements more frequently than the current master.
                   1090: Disabled by default.
                   1091: .It Li ip.allowsrcrt
                   1092: If set to 1, the host accepts source routed packets.
                   1093: .It Li ip.anonportmax
                   1094: The highest port number to use for TCP and UDP ephemeral port allocation.
                   1095: This cannot be set to less than 1024 or greater than 65535, and must
                   1096: be greater than
                   1097: .Li ip.anonportmin .
                   1098: .It Li ip.anonportmin
                   1099: The lowest port number to use for TCP and UDP ephemeral port allocation.
                   1100: This cannot be set to less than 1024 or greater than 65535.
                   1101: .It Li ip.checkinterface
                   1102: If set to non-zero, the host will reject packets addressed to it
                   1103: that arrive on an interface not bound to that address.
                   1104: Currently, this must be disabled if ipnat is used to translate the
                   1105: destination address to another local interface, or if addresses
                   1106: are added to the loopback interface instead of the interface where
                   1107: the packets for those packets are received.
                   1108: .It Li ip.directed-broadcast
                   1109: If set to 1, enables directed broadcast behavior for the host.
                   1110: .It Li ip.do_loopback_cksum
                   1111: Perform IP checksum on loopback.
                   1112: .It Li ip.forwarding
                   1113: If set to 1, enables IP forwarding for the host,
                   1114: meaning that the host is acting as a router.
                   1115: .It Li ip.forwsrcrt
                   1116: If set to 1, enables forwarding of source-routed packets for the host.
                   1117: This value may only be changed if the kernel security level is less than 1.
                   1118: .It Li ip.gifttl
                   1119: The maximum time-to-live (hop count) value for an IPv4 packet generated by
                   1120: .Xr gif 4
                   1121: tunnel interface.
                   1122: .It Li ip.grettl
                   1123: The maximum time-to-live (hop count) value for an IPv4 packet generated by
                   1124: .Xr gre 4
                   1125: tunnel interface.
1.8       liamjfoy 1126: .It Li ip.hashsize
                   1127: The size of IPv4 Fast Forward hash table.
                   1128: This value must be a power of 2 (64, 256...).
                   1129: A larger hash table size results in fewer collisions.
                   1130: Also see
                   1131: .Li ip.maxflows .
1.1       pavel    1132: .It Li ip.hostzerobroadcast
                   1133: All zeroes address is broadcast address.
                   1134: .It Li ip.lowportmax
                   1135: The highest port number to use for TCP and UDP reserved port allocation.
                   1136: This cannot be set to less than 0 or greater than 1024, and must
                   1137: be greater than
                   1138: .Li ip.lowportmin .
                   1139: .It Li ip.lowportmin
                   1140: The lowest port number to use for TCP and UDP reserved port allocation.
                   1141: This cannot be set to less than 0 or greater than 1024, and must
                   1142: be smaller than
                   1143: .Li ip.lowportmax .
                   1144: .It Li ip.maxflows
1.5       liamjfoy 1145: IPv4 Fast Forwarding is enabled by default.
                   1146: If set to 0, IPv4 Fast Forwarding is disabled.
1.1       pavel    1147: .Li ip.maxflows
                   1148: controls the maximum amount of flows which can be created.
                   1149: The default value is 256.
                   1150: .It Li ip.maxfragpackets
                   1151: The maximum number of fragmented packets the node will accept.
                   1152: 0 means that the node will not accept any fragmented packets.
                   1153: \-1 means that the node will accept as many fragmented packets as it receives.
                   1154: The flag is provided basically for avoiding possible DoS attacks.
                   1155: .It Li ip.mtudisc
                   1156: If set to 1, enables Path MTU Discovery (RFC 1191).
                   1157: When Path MTU Discovery is enabled, the transmitted TCP segment
                   1158: size will be determined by the advertised maximum segment size
                   1159: (MSS) from the remote end, as constrained by the path MTU.
                   1160: If MTU Discovery is disabled, the transmitted segment size will
                   1161: never be greater than
                   1162: .Li tcp.mssdflt
                   1163: (the local maximum segment size).
                   1164: .It Li ip.mtudisctimeout
                   1165: The number of seconds in which a route added by the Path MTU
                   1166: Discovery engine will time out.
                   1167: When the route times out, the Path
                   1168: MTU Discovery engine will attempt to probe a larger path MTU.
                   1169: .It Li ip.random_id
                   1170: Assign random ip_id values.
                   1171: .It Li ip.redirect
                   1172: If set to 1, ICMP redirects may be sent by the host.
                   1173: This option is ignored unless the host is routing IP packets,
                   1174: and should normally be enabled on all systems.
                   1175: .It Li ip.subnetsarelocal
                   1176: If set to 1, subnets are to be considered local addresses.
                   1177: .It Li ip.ttl
                   1178: The maximum time-to-live (hop count) value for an IP packet sourced by
                   1179: the system.
                   1180: This value applies to normal transport protocols, not to ICMP.
                   1181: .It Li icmp.errppslimit
                   1182: The variable specifies the maximum number of outgoing ICMP error messages,
                   1183: per second.
                   1184: ICMP error messages that exceeded the value are subject to rate limitation
                   1185: and will not go out from the node.
                   1186: Negative value disables rate limitation.
                   1187: .It Li icmp.maskrepl
                   1188: If set to 1, ICMP network mask requests are to be answered.
                   1189: .It Li icmp.rediraccept
                   1190: If set to non-zero, the host will accept ICMP redirect packets.
                   1191: Note that routers will never accept ICMP redirect packets,
                   1192: and the variable is meaningful on IP hosts only.
                   1193: .It Li icmp.redirtimeout
                   1194: The variable specifies lifetime of routing entries generated by incoming
                   1195: ICMP redirect.
                   1196: This defaults to 600 seconds.
                   1197: .It Li icmp.returndatabytes
                   1198: Number of bytes to return in an ICMP error message.
1.28      christos 1199: .It Li icmp.bmcastecho
                   1200: If set to 1, enables responding to ICMP echo or timestamp request to the
                   1201: broadcast address.
1.1       pavel    1202: .It Li tcp.ack_on_push
                   1203: If set to 1, TCP is to immediately transmit an ACK upon reception of
                   1204: a packet with PUSH set.
                   1205: This can avoid losing a round trip time in some rare situations,
                   1206: but has the caveat of potentially defeating TCP's delayed ACK algorithm.
                   1207: Use of this option is generally not recommended, but
                   1208: the variable exists in case your configuration really needs it.
                   1209: .It Li tcp.compat_42
                   1210: If set to 1, enables work-arounds for bugs in the 4.2BSD TCP implementation.
                   1211: Use of this option is not recommended, although it may be
                   1212: required in order to communicate with extremely old TCP implementations.
                   1213: .It Li tcp.cwm
                   1214: If set to 1, enables use of the Hughes/Touch/Heidemann Congestion Window
                   1215: Monitoring algorithm.
                   1216: This algorithm prevents line-rate bursts of packets that could
                   1217: otherwise occur when data begins flowing on an idle TCP connection.
                   1218: These line-rate bursts can contribute to network and router congestion.
                   1219: This can be particularly useful on World Wide Web servers
                   1220: which support HTTP/1.1, which has lingering connections.
                   1221: .It Li tcp.cwm_burstsize
                   1222: The Congestion Window Monitoring allowed burst size, in terms
                   1223: of packet count.
                   1224: .It Li tcp.delack_ticks
                   1225: Number of ticks to delay sending an ACK.
                   1226: .It Li tcp.do_loopback_cksum
                   1227: Perform TCP checksum on loopback.
                   1228: .It Li tcp.init_win
                   1229: A value indicating the TCP initial congestion window.
                   1230: If this value is 0, an auto-tuning algorithm designed to use an initial
                   1231: window of approximately 4K bytes is in use.
                   1232: Otherwise, this value indicates a fixed number of packets.
                   1233: .It Li tcp.init_win_local
                   1234: Like
                   1235: .Li tcp.init_win ,
                   1236: but used when communicating with hosts on a local network.
                   1237: .It Li tcp.keepcnt
                   1238: Number of keepalive probes sent before declaring a connection dead.
                   1239: If set to zero, there is no limit;
                   1240: keepalives will be sent until some kind of
                   1241: response is received from the peer.
                   1242: .It Li tcp.keepidle
                   1243: Time a connection must be idle before keepalives are sent (if keepalives
                   1244: are enabled for the connection).
                   1245: See also tcp.slowhz.
                   1246: .It Li tcp.keepintvl
                   1247: Time after a keepalive probe is sent until, in the absence of any response,
                   1248: another probe is sent.
                   1249: See also tcp.slowhz.
                   1250: .It Li tcp.log_refused
                   1251: If set to 1, refused TCP connections to the host will be logged.
1.12      christos 1252: .It Li tcp.keepinit
                   1253: Timeout in seconds during connection establishment.
1.1       pavel    1254: .It Li tcp.mss_ifmtu
                   1255: If set to 1, TCP calculates the outgoing maximum segment size based on
                   1256: the MTU of the appropriate interface.
                   1257: If set to 0, it is calculated based on the greater of the MTU of the
                   1258: interface, and the largest (non-loopback) interface MTU on the system.
                   1259: .It Li tcp.mssdflt
                   1260: The default maximum segment size both advertised to the peer
                   1261: and to use when either the peer does not advertise a maximum segment size to
                   1262: us during connection setup or Path MTU Discovery
                   1263: .Li ( ip.mtudisc )
                   1264: is disabled.
                   1265: Do not change this value unless you really know what you are doing.
                   1266: .It Li tcp.recvspace
                   1267: The default TCP receive buffer size.
                   1268: .It Li tcp.rfc1323
                   1269: If set to 1, enables RFC 1323 extensions to TCP.
                   1270: .It Li tcp.rstppslimit
                   1271: The variable specifies the maximum number of outgoing TCP RST packets,
                   1272: per second.
                   1273: TCP RST packet that exceeded the value are subject to rate limitation
                   1274: and will not go out from the node.
                   1275: Negative value disables rate limitation.
1.13      christos 1276: .It Li tcp.ident
                   1277: Return the user ID of a connected socket pair.
                   1278: (RFC1413 Identification Protocol lookups.)
                   1279: .It Li tcp.drop
                   1280: Drop a TCP socket pair connection.
1.1       pavel    1281: .It Li tcp.sack.enable
                   1282: If set to 1, enables RFC 2018 Selective ACKnowledgement.
                   1283: .It Li tcp.sack.globalholes
                   1284: Global number of TCP SACK holes.
                   1285: .It Li tcp.sack.globalmaxholes
                   1286: Global maximum number of TCP SACK holes.
                   1287: .It Li tcp.sack.maxholes
                   1288: Maximum number of TCP SACK holes allowed per connection.
                   1289: .It Li tcp.ecn.enable
                   1290: If set to 1, enables RFC 3168 Explicit Congestion Notification.
                   1291: .It Li tcp.ecn.maxretries
                   1292: Number of times to retry sending the ECN-setup packet.
                   1293: .It Li tcp.sendspace
                   1294: The default TCP send buffer size.
                   1295: .It Li tcp.slowhz
                   1296: The units for tcp.keepidle and tcp.keepintvl; those variables are in ticks
                   1297: of a clock that ticks tcp.slowhz times per second.
                   1298: (That is, their values
                   1299: must be divided by the tcp.slowhz value to get times in seconds.)
                   1300: .It Li tcp.syn_bucket_limit
                   1301: The maximum number of entries allowed per hash bucket in the TCP
                   1302: compressed state engine.
                   1303: .It Li tcp.syn_cache_limit
                   1304: The maximum number of entries allowed in the TCP compressed state
                   1305: engine.
                   1306: .It Li tcp.timestamps
                   1307: If rfc1323 is enabled, a value of 1 indicates RFC 1323 time stamp options,
                   1308: used for measuring TCP round trip times, are enabled.
                   1309: .It Li tcp.win_scale
                   1310: If rfc1323 is enabled, a value of 1 indicates RFC 1323 window scale options,
                   1311: for increasing the TCP window size, are enabled.
                   1312: .It Li tcp.congctl.available
                   1313: The available TCP congestion control algorithms.
                   1314: .It Li tcp.congctl.selected
                   1315: The currently selected TCP congestion control algorithm.
                   1316: .It Li tcp.abc.enable
                   1317: If set to 1, use RFC 3465 Appropriate Byte Counting (ABC).
                   1318: If set to 0, use traditional Packet Counting.
                   1319: .It Li tcp.abc.aggressive
                   1320: Choose the L parameter found in RFC 3465.
                   1321: L is the maximum cwnd increase for an ack during slow start.
                   1322: If set to 1, use L=2*SMSS.
                   1323: If set to 0, use L=1*SMSS.
                   1324: It has no effect unless tcp.abc.enable is set to 1.
                   1325: .It Li udp.checksum
                   1326: If set to 1, UDP checksums are being computed.
                   1327: Received non-zero UDP checksums are always checked.
                   1328: Disabling UDP checksums is strongly discouraged.
                   1329: .It Li udp.sendspace
                   1330: The default UDP send buffer size.
                   1331: .It Li udp.recvspace
                   1332: The default UDP receive buffer size.
                   1333: .El
                   1334: .Pp
                   1335: For variables net.*.ipsec, please refer to
                   1336: .Xr ipsec 4 .
                   1337: .It Li net.inet6 ( PF_INET6 )
                   1338: Get or set various global information about the IPv6
                   1339: .Pq Internet Protocol version 6 .
                   1340: The third level name is the protocol.
                   1341: The fourth level name is the variable name.
                   1342: The currently defined protocols and names are:
1.21      joerg    1343: .Bl -column "Protocol name" "do_loopback_cksum" "integer" "Changeable" -offset indent
1.1       pavel    1344: .It Sy Protocol name   Variable name   Type    Changeable
                   1345: .It icmp6      errppslimit     integer yes
                   1346: .It icmp6      mtudisc_hiwat   integer yes
                   1347: .It icmp6      mtudisc_lowat   integer yes
                   1348: .It icmp6      nd6_debug       integer yes
                   1349: .It icmp6      nd6_delay       integer yes
                   1350: .It icmp6      nd6_maxnudhint  integer yes
                   1351: .It icmp6      nd6_mmaxtries   integer yes
                   1352: .It icmp6      nd6_prune       integer yes
                   1353: .It icmp6      nd6_umaxtries   integer yes
                   1354: .It icmp6      nd6_useloopback integer yes
                   1355: .It icmp6      nodeinfo        integer yes
                   1356: .It icmp6      rediraccept     integer yes
                   1357: .It icmp6      redirtimeout    integer yes
                   1358: .It ip6        accept_rtadv    integer yes
                   1359: .It ip6        anonportmax     integer yes
                   1360: .It ip6        anonportmin     integer yes
                   1361: .It ip6        auto_flowlabel  integer yes
                   1362: .It ip6        dad_count       integer yes
                   1363: .It ip6        defmcasthlim    integer yes
                   1364: .It ip6        forwarding      integer yes
                   1365: .It ip6        gifhlim integer yes
1.7       liamjfoy 1366: .It ip6        hashsize        integer yes
1.1       pavel    1367: .It ip6        hlim    integer yes
                   1368: .It ip6        hdrnestlimit    integer yes
                   1369: .It ip6        kame_version    string  no
                   1370: .It ip6        keepfaith       integer yes
                   1371: .It ip6        log_interval    integer yes
                   1372: .It ip6        lowportmax      integer yes
                   1373: .It ip6        lowportmin      integer yes
1.5       liamjfoy 1374: .It ip6        maxflows        integer yes
1.1       pavel    1375: .It ip6        maxfragpackets  integer yes
                   1376: .It ip6        maxfrags        integer yes
                   1377: .It ip6        redirect        integer yes
                   1378: .It ip6        rr_prune        integer yes
                   1379: .It ip6        use_deprecated  integer yes
                   1380: .It ip6        v6only  integer yes
                   1381: .It udp6       do_loopback_cksum       integer yes
                   1382: .It udp6       recvspace       integer yes
                   1383: .It udp6       sendspace       integer yes
                   1384: .El
                   1385: .Pp
                   1386: The variables are as follows:
                   1387: .Bl -tag -width "123456"
                   1388: .It Li ip6.accept_rtadv
                   1389: If set to non-zero, the node will accept ICMPv6 router advertisement packets
                   1390: and autoconfigures address prefixes and default routers.
                   1391: The node must be a host
                   1392: .Pq not a router
                   1393: for the option to be meaningful.
                   1394: .It Li ip6.anonportmax
                   1395: The highest port number to use for TCP and UDP ephemeral port allocation.
                   1396: This cannot be set to less than 1024 or greater than 65535, and must
                   1397: be greater than
                   1398: .Li ip6.anonportmin .
                   1399: .It Li ip6.anonportmin
                   1400: The lowest port number to use for TCP and UDP ephemeral port allocation.
                   1401: This cannot be set to less than 1024 or greater than 65535.
                   1402: .It Li ip6.auto_flowlabel
                   1403: On connected transport protocol packets,
                   1404: fill IPv6 flowlabel field to help intermediate routers to identify packet flows.
                   1405: .It Li ip6.dad_count
                   1406: The variable configures number of IPv6 DAD
                   1407: .Pq duplicated address detection
                   1408: probe packets.
                   1409: The packets will be generated when IPv6 interface addresses are configured.
                   1410: .It Li ip6.defmcasthlim
                   1411: The default hop limit value for an IPv6 multicast packet sourced by the node.
                   1412: This value applies to all the transport protocols on top of IPv6.
                   1413: There are APIs to override the value, as documented in
                   1414: .Xr ip6 4 .
                   1415: .It Li ip6.forwarding
                   1416: If set to 1, enables IPv6 forwarding for the node,
                   1417: meaning that the node is acting as a router.
                   1418: If set to 0, disables IPv6 forwarding for the node,
                   1419: meaning that the node is acting as a host.
                   1420: IPv6 specification defines node behavior for
                   1421: .Dq router
                   1422: case and
                   1423: .Dq host
                   1424: case quite differently, and changing this variable during operation
                   1425: may cause serious trouble.
                   1426: It is recommended to configure the variable at bootstrap time,
                   1427: and bootstrap time only.
                   1428: .It Li ip6.gifhlim
                   1429: The maximum hop limit value for an IPv6 packet generated by
                   1430: .Xr gif 4
                   1431: tunnel interface.
                   1432: .It Li ip6.hdrnestlimit
                   1433: The number of IPv6 extension headers permitted on incoming IPv6 packets.
                   1434: If set to 0, the node will accept as many extension headers as possible.
1.7       liamjfoy 1435: .It Li ip6.hashsize
                   1436: The size of IPv6 Fast Forward hash table.
                   1437: This value must be a power of 2 (64, 256...).
                   1438: A larger hash table size results in fewer collisions.
                   1439: Also see
                   1440: .Li ip6.maxflows .
1.1       pavel    1441: .It Li ip6.hlim
                   1442: The default hop limit value for an IPv6 unicast packet sourced by the node.
                   1443: This value applies to all the transport protocols on top of IPv6.
                   1444: There are APIs to override the value, as documented in
                   1445: .Xr ip6 4 .
                   1446: .It Li ip6.kame_version
                   1447: The string identifies the version of KAME IPv6 stack implemented in the kernel.
                   1448: .It Li ip6.keepfaith
                   1449: If set to non-zero, it enables
                   1450: .Dq FAITH
                   1451: TCP relay IPv6-to-IPv4 translator code in the kernel.
                   1452: Refer
                   1453: .Xr faith 4
                   1454: and
                   1455: .Xr faithd 8
                   1456: for detail.
                   1457: .It Li ip6.log_interval
                   1458: The variable controls amount of logs generated by IPv6 packet
                   1459: forwarding engine, by setting interval between log output
                   1460: .Pq in seconds .
                   1461: .It Li ip6.lowportmax
                   1462: The highest port number to use for TCP and UDP reserved port allocation.
                   1463: This cannot be set to less than 0 or greater than 1024, and must
                   1464: be greater than
                   1465: .Li ip6.lowportmin .
                   1466: .It Li ip6.lowportmin
                   1467: The lowest port number to use for TCP and UDP reserved port allocation.
                   1468: This cannot be set to less than 0 or greater than 1024, and must
                   1469: be smaller than
                   1470: .Li ip6.lowportmax .
1.5       liamjfoy 1471: .It Li ip6.maxflows
                   1472: IPv6 Fast Forwarding is enabled by default.
                   1473: If set to 0, IPv6 Fast Forwarding is disabled.
                   1474: .Li ip6.maxflows
                   1475: controls the maximum amount of flows which can be created.
1.6       liamjfoy 1476: The default value is 256.
1.1       pavel    1477: .It Li ip6.maxfragpackets
                   1478: The maximum number of fragmented packets the node will accept.
                   1479: 0 means that the node will not accept any fragmented packets.
                   1480: \-1 means that the node will accept as many fragmented packets as it receives.
                   1481: The flag is provided basically for avoiding possible DoS attacks.
                   1482: .It Li ip6.maxfrags
                   1483: The maximum number of fragments the node will accept.
                   1484: 0 means that the node will not accept any fragments.
                   1485: \-1 means that the node will accept as many fragments as it receives.
                   1486: The flag is provided basically for avoiding possible DoS attacks.
                   1487: .It Li ip6.redirect
                   1488: If set to 1, ICMPv6 redirects may be sent by the node.
                   1489: This option is ignored unless the node is routing IP packets,
                   1490: and should normally be enabled on all systems.
                   1491: .It Li ip6.rr_prune
                   1492: The variable specifies interval between IPv6 router renumbering prefix
                   1493: babysitting, in seconds.
                   1494: .It Li ip6.use_deprecated
                   1495: The variable controls use of deprecated address, specified in RFC 2462 5.5.4.
                   1496: .It Li ip6.v6only
                   1497: The variable specifies initial value for
                   1498: .Dv IPV6_V6ONLY
                   1499: socket option for
                   1500: .Dv AF_INET6
                   1501: socket.
                   1502: Please refer to
                   1503: .Xr ip6 4
                   1504: for detail.
                   1505: .It Li icmp6.errppslimit
                   1506: The variable specifies the maximum number of outgoing ICMPv6 error messages,
                   1507: per second.
                   1508: ICMPv6 error messages that exceeded the value are subject to rate limitation
                   1509: and will not go out from the node.
                   1510: Negative value disables rate limitation.
                   1511: .It Li icmp6.mtudisc_hiwat
                   1512: .It Li icmp6.mtudisc_lowat
                   1513: The variables define the maximum number of routing table entries,
                   1514: created due to path MTU discovery
                   1515: .Pq prevents denial-of-service attacks with ICMPv6 too big messages .
                   1516: When IPv6 path MTU discovery happens, we keep path MTU information into
                   1517: the routing table.
                   1518: If the number of routing table entries exceed the value,
                   1519: the kernel will not attempt to keep the path MTU information.
                   1520: .Li icmp6.mtudisc_hiwat
                   1521: is used when we have verified ICMPv6 too big messages.
                   1522: .Li icmp6.mtudisc_lowat
                   1523: is used when we have unverified ICMPv6 too big messages.
                   1524: Verification is performed by using address/port pairs kept in connected pcbs.
                   1525: Negative value disables the upper limit.
                   1526: .It Li icmp6.nd6_debug
                   1527: If set to non-zero, kernel IPv6 neighbor discovery code will generate
                   1528: debugging messages.
                   1529: The debug outputs are useful to diagnose IPv6 interoperability issues.
                   1530: The flag must be set to 0 for normal operation.
                   1531: .It Li icmp6.nd6_delay
                   1532: The variable specifies
                   1533: .Dv DELAY_FIRST_PROBE_TIME
                   1534: timing constant in IPv6 neighbor discovery specification
                   1535: .Pq RFC 2461 ,
                   1536: in seconds.
                   1537: .It Li icmp6.nd6_maxnudhint
                   1538: IPv6 neighbor discovery permits upper layer protocols to supply reachability
                   1539: hints, to avoid unnecessary neighbor discovery exchanges.
                   1540: The variable defines the number of consecutive hints the neighbor discovery
                   1541: layer will take.
                   1542: For example, by setting the variable to 3, neighbor discovery layer
                   1543: will take 3 consecutive hints in maximum.
                   1544: After receiving 3 hints, neighbor discovery layer will perform
                   1545: normal neighbor discovery process.
                   1546: .It Li icmp6.nd6_mmaxtries
                   1547: The variable specifies
                   1548: .Dv MAX_MULTICAST_SOLICIT
                   1549: constant in IPv6 neighbor discovery specification
                   1550: .Pq RFC 2461 .
                   1551: .It Li icmp6.nd6_prune
                   1552: The variable specifies interval between IPv6 neighbor cache babysitting,
                   1553: in seconds.
                   1554: .It Li icmp6.nd6_umaxtries
                   1555: The variable specifies
                   1556: .Dv MAX_UNICAST_SOLICIT
                   1557: constant in IPv6 neighbor discovery specification
                   1558: .Pq RFC 2461 .
                   1559: .It Li icmp6.nd6_useloopback
                   1560: If set to non-zero, kernel IPv6 stack will use loopback interface for
                   1561: local traffic.
                   1562: .It Li icmp6.nodeinfo
                   1563: The variable enables responses to ICMPv6 node information queries.
                   1564: If you set the variable to 0, responses will not be generated for
                   1565: ICMPv6 node information queries.
                   1566: Since node information queries can have a security impact, it is
                   1567: possible to fine tune which responses should be answered.
                   1568: Two separate bits can be set.
                   1569: .Bl -tag -width "12345"
                   1570: .It 1
                   1571: Respond to ICMPv6 FQDN queries, e.g.
                   1572: .Li ping6 -w .
                   1573: .It 2
                   1574: Respond to ICMPv6 node addresses queries, e.g.
                   1575: .Li ping6 -a .
                   1576: .El
                   1577: .It Li icmp6.rediraccept
                   1578: If set to non-zero, the host will accept ICMPv6 redirect packets.
                   1579: Note that IPv6 routers will never accept ICMPv6 redirect packets,
                   1580: and the variable is meaningful on IPv6 hosts
                   1581: .Pq non-router
                   1582: only.
                   1583: .It Li icmp6.redirtimeout
                   1584: The variable specifies lifetime of routing entries generated by incoming
                   1585: ICMPv6 redirect.
                   1586: .It Li udp6.do_loopback_cksum
                   1587: Perform UDP checksum on loopback.
                   1588: .It Li udp6.recvspace
                   1589: Default UDP receive buffer size.
                   1590: .It Li udp6.sendspace
                   1591: Default UDP send buffer size.
                   1592: .El
                   1593: .Pp
                   1594: We reuse net.*.tcp for
                   1595: .Tn TCP
                   1596: over
                   1597: .Tn IPv6 ,
                   1598: and therefore we do not have variables net.*.tcp6.
                   1599: Variables net.inet6.udp6 have identical meaning to net.inet.udp.
                   1600: Please refer to
                   1601: .Li PF_INET
                   1602: section above.
                   1603: For variables net.*.ipsec6, please refer to
                   1604: .Xr ipsec 4 .
                   1605: .It Li net.key ( PF_KEY )
                   1606: Get or set various global information about the IPsec key management.
                   1607: The third level name is the variable name.
                   1608: The currently defined variable and names are:
1.21      joerg    1609: .Bl -column "blockacq_lifetime" "integer" "Changeable" -offset indent
1.1       pavel    1610: .It Sy Variable name   Type    Changeable
                   1611: .It debug      integer yes
                   1612: .It spi_try    integer yes
                   1613: .It spi_min_value      integer yes
                   1614: .It spi_max_value      integer yes
                   1615: .It larval_lifetime    integer yes
                   1616: .It blockacq_count     integer yes
                   1617: .It blockacq_lifetime  integer yes
                   1618: .It esp_keymin integer yes
                   1619: .It esp_auth   integer yes
                   1620: .It ah_keymin  integer yes
                   1621: .El
1.21      joerg    1622: .Pp
1.1       pavel    1623: The variables are as follows:
                   1624: .Bl -tag -width "123456"
                   1625: .It Li debug
                   1626: Turn on debugging message from within the kernel.
                   1627: The value is a bitmap, as defined in
                   1628: .Pa /usr/include/netkey/key_debug.h .
                   1629: .It Li spi_try
                   1630: The number of times the kernel will try to obtain an unique SPI
                   1631: when it generates it from random number generator.
                   1632: .It Li spi_min_value
                   1633: Minimum SPI value when generating it within the kernel.
                   1634: .It Li spi_max_value
                   1635: Maximum SPI value when generating it within the kernel.
                   1636: .It Li larval_lifetime
                   1637: Lifetime for LARVAL SAD entries, in seconds.
                   1638: .It Li blockacq_count
                   1639: Number of ACQUIRE PF_KEY messages to be blocked after an ACQUIRE message.
                   1640: It avoids flood of ACQUIRE PF_KEY from being sent from the kernel to the
                   1641: key management daemon.
                   1642: .It Li blockacq_lifetime
                   1643: Lifetime of ACQUIRE PF_KEY message.
                   1644: .It Li esp_keymin
                   1645: Minimum ESP key length, in bits.
                   1646: The value is used when the kernel creates proposal payload
                   1647: on ACQUIRE PF_KEY message.
                   1648: .It Li esp_auth
                   1649: Whether ESP authentication should be used or not.
                   1650: Non-zero value indicates that ESP authentication should be used.
                   1651: The value is used when the kernel creates proposal payload
                   1652: on ACQUIRE PF_KEY message.
                   1653: .It Li ah_keymin
                   1654: Minimum AH key length, in bits,
                   1655: The value is used when the kernel creates proposal payload
                   1656: on ACQUIRE PF_KEY message.
                   1657: .El
                   1658: .El
                   1659: .Sh The proc.* subtree
                   1660: The string and integer information available for the
                   1661: .Li proc
                   1662: level is detailed below.
                   1663: The changeable column shows whether a process with appropriate
                   1664: privilege may change the value.
                   1665: These values are per-process,
                   1666: and as such may change from one process to another.
                   1667: When a process is created,
                   1668: the default values are inherited from its parent.
                   1669: When a set-user-ID or set-group-ID binary is executed, the
                   1670: value of PROC_PID_CORENAME is reset to the system default value.
                   1671: The second level name is either the magic value PROC_CURPROC, which
                   1672: points to the current process, or the PID of the target process.
1.21      joerg    1673: .Bl -column "proc.pid.corename" "string" "not applicable" -offset indent
1.1       pavel    1674: .It Sy Third level name        Type    Changeable
                   1675: .It proc.pid.corename  string  yes
                   1676: .It proc.pid.rlimit    node    not applicable
                   1677: .It proc.pid.stopfork  int     yes
                   1678: .It proc.pid.stopexec  int     yes
                   1679: .It proc.pid.stopexit  int     yes
                   1680: .El
                   1681: .Bl -tag -width "123456"
                   1682: .It Li proc.pid.corename ( PROC_PID_CORENAME )
                   1683: The template used for the core dump file name (see
                   1684: .Xr core 5
                   1685: for details).
                   1686: The base name must either be
                   1687: .Nm core
                   1688: or end with the suffix ``.core'' (the super-user may set arbitrary names).
                   1689: By default it points to KERN_DEFCORENAME.
                   1690: .It Li proc.pid.rlimit ( PROC_PID_LIMIT )
                   1691: Return resources limits, as defined for the
                   1692: .Xr getrlimit 2
                   1693: and
                   1694: .Xr setrlimit 2
                   1695: system calls.
                   1696: The fourth level name is one of:
                   1697: .Bl -tag -width PROC_PID_LIMIT_MEMLOCKAA
                   1698: .It Li proc.pid.rlimit.cputime ( PROC_PID_LIMIT_CPU )
                   1699: The maximum amount of CPU time (in seconds) to be used by each process.
                   1700: .It Li proc.pid.rlimit.filesize ( PROC_PID_LIMIT_FSIZE )
                   1701: The largest size (in bytes) file that may be created.
                   1702: .It Li proc.pid.rlimit.datasize ( PROC_PID_LIMIT_DATA )
                   1703: The maximum size (in bytes) of the data segment for a process;
                   1704: this defines how far a program may extend its break with the
                   1705: .Xr sbrk 2
                   1706: system call.
                   1707: .It Li proc.pid.rlimit.stacksize ( PROC_PID_LIMIT_STACK )
                   1708: The maximum size (in bytes) of the stack segment for a process;
                   1709: this defines how far a program's stack segment may be extended.
                   1710: Stack extension is performed automatically by the system.
                   1711: .It Li proc.pid.rlimit.coredumpsize ( PROC_PID_LIMIT_CORE )
                   1712: The largest size (in bytes)
                   1713: .Pa core
                   1714: file that may be created.
                   1715: .It Li proc.pid.rlimit.memoryuse ( PROC_PID_LIMIT_RSS )
                   1716: The maximum size (in bytes) to which a process's resident set size may
                   1717: grow.
                   1718: This imposes a limit on the amount of physical memory to be given to
                   1719: a process; if memory is tight, the system will prefer to take memory
                   1720: from processes that are exceeding their declared resident set size.
                   1721: .It Li proc.pid.rlimit.memorylocked ( PROC_PID_LIMIT_MEMLOCK )
                   1722: The maximum size (in bytes) which a process may lock into memory
                   1723: using the
                   1724: .Xr mlock 2
                   1725: function.
                   1726: .It Li proc.pid.rlimit.maxproc ( PROC_PID_LIMIT_NPROC )
                   1727: The maximum number of simultaneous processes for this user id.
                   1728: .It Li proc.pid.rlimit.descriptors ( PROC_PID_LIMIT_NOFILE )
                   1729: The maximum number of open files for this process.
1.22      snj      1730: .It Li proc.pid.rlimit.sbsize ( PROC_PID_LIMIT_SBSIZE )
                   1731: The maximum size (in bytes) of the socket buffers
                   1732: set by the
                   1733: .Xr setsockopt 2
                   1734: .Dv SO_RCVBUF
                   1735: and
                   1736: .Dv SO_SNDBUF
                   1737: options.
1.1       pavel    1738: .El
                   1739: .Pp
                   1740: The fifth level name is one of
                   1741: .Li soft ( PROC_PID_LIMIT_TYPE_SOFT ) or
                   1742: .Li hard ( PROC_PID_LIMIT_TYPE_HARD ) ,
                   1743: to select respectively the soft or hard limit.
                   1744: Both are of type integer.
                   1745: .It Li proc.pid.stopfork ( PROC_PID_STOPFORK )
                   1746: If non zero, the process' children will be stopped after
                   1747: .Xr fork 2
                   1748: calls.
                   1749: The children is created in the SSTOP state and is never scheduled
                   1750: for running before being stopped.
                   1751: This feature helps attaching a process with a debugger such as
                   1752: .Xr gdb 1
                   1753: before it had the opportunity to actually do anything.
                   1754: .Pp
                   1755: This value is inherited by the process's children, and it also
                   1756: apply to emulation specific system calls that fork a new process, such as
                   1757: .Fn sproc
                   1758: or
                   1759: .Fn clone .
                   1760: .It Li proc.pid.stopexec ( PROC_PID_STOPEXEC )
                   1761: If non zero, the process will be stopped on next
                   1762: .Xr exec 3
                   1763: call.
                   1764: The process created by
                   1765: .Xr exec 3
                   1766: is created in the SSTOP state and is never scheduled for running
                   1767: before being stopped.
                   1768: This feature helps attaching a process with a debugger such as
                   1769: .Xr gdb 1
                   1770: before it had the opportunity to actually do anything.
                   1771: .Pp
                   1772: This value is inherited by the process's children.
                   1773: .It Li proc.pid.stopexit ( PROC_PID_STOPEXIT )
                   1774: If non zero, the process will be stopped on when it has cause to exit,
                   1775: either by way of calling
                   1776: .Xr exit 3 ,
                   1777: .Xr _exit 2 ,
                   1778: or by the receipt of a specific signal.
                   1779: The process is stopped before any of its resources or vm space is
                   1780: released allowing examination of the termination state of a process
                   1781: before it disappears.
                   1782: This feature can be used to examine the final conditions of the
                   1783: process's vmspace via
                   1784: .Xr pmap 1
                   1785: or its resource settings with
                   1786: .Xr sysctl 8
                   1787: before it disappears.
                   1788: .Pp
                   1789: This value is also inherited by the process's children.
                   1790: .El
                   1791: .Sh The user.* subtree ( CTL_USER )
                   1792: The string and integer information available for the
                   1793: .Li user
                   1794: level is detailed below.
                   1795: The changeable column shows whether a process with appropriate
                   1796: privilege may change the value.
1.21      joerg    1797: .Bl -column "user.coll_weights_max" "integer" "Changeable" -offset indent
1.1       pavel    1798: .It Sy Second level name       Type    Changeable
                   1799: .It user.atexit_max    integer no
                   1800: .It user.bc_base_max   integer no
                   1801: .It user.bc_dim_max    integer no
                   1802: .It user.bc_scale_max  integer no
                   1803: .It user.bc_string_max integer no
                   1804: .It user.coll_weights_max      integer no
                   1805: .It user.cs_path       string  no
                   1806: .It user.expr_nest_max integer no
                   1807: .It user.line_max      integer no
                   1808: .It user.posix2_c_bind integer no
                   1809: .It user.posix2_c_dev  integer no
                   1810: .It user.posix2_char_term      integer no
                   1811: .It user.posix2_fort_dev       integer no
                   1812: .It user.posix2_fort_run       integer no
                   1813: .It user.posix2_localedef      integer no
                   1814: .It user.posix2_sw_dev integer no
                   1815: .It user.posix2_upe    integer no
                   1816: .It user.posix2_version        integer no
                   1817: .It user.re_dup_max    integer no
                   1818: .It user.stream_max    integer no
                   1819: .It user.stream_max    integer no
                   1820: .It user.tzname_max    integer no
                   1821: .El
                   1822: .Bl -tag -width "123456"
                   1823: .It Li user.atexit_max ( USER_ATEXIT_MAX )
                   1824: The maximum number of functions that may be registered with
                   1825: .Xr atexit 3 .
                   1826: .It Li user.bc_base_max ( USER_BC_BASE_MAX )
                   1827: The maximum ibase/obase values in the
                   1828: .Xr bc 1
                   1829: utility.
                   1830: .It Li user.bc_dim_max ( USER_BC_DIM_MAX )
                   1831: The maximum array size in the
                   1832: .Xr bc 1
                   1833: utility.
                   1834: .It Li user.bc_scale_max ( USER_BC_SCALE_MAX )
                   1835: The maximum scale value in the
                   1836: .Xr bc 1
                   1837: utility.
                   1838: .It Li user.bc_string_max ( USER_BC_STRING_MAX )
                   1839: The maximum string length in the
                   1840: .Xr bc 1
                   1841: utility.
                   1842: .It Li user.coll_weights_max ( USER_COLL_WEIGHTS_MAX )
                   1843: The maximum number of weights that can be assigned to any entry of
                   1844: the LC_COLLATE order keyword in the locale definition file.
                   1845: .It Li user.cs_path ( USER_CS_PATH )
                   1846: Return a value for the
                   1847: .Ev PATH
                   1848: environment variable that finds all the standard utilities.
                   1849: .It Li user.expr_nest_max ( USER_EXPR_NEST_MAX )
                   1850: The maximum number of expressions that can be nested within
                   1851: parenthesis by the
                   1852: .Xr expr 1
                   1853: utility.
                   1854: .It Li user.line_max ( USER_LINE_MAX )
                   1855: The maximum length in bytes of a text-processing utility's input
                   1856: line.
                   1857: .It Li user.posix2_char_term ( USER_POSIX2_CHAR_TERM )
                   1858: Return 1 if the system supports at least one terminal type capable of
                   1859: all operations described in POSIX 1003.2, otherwise 0.
                   1860: .It Li user.posix2_c_bind ( USER_POSIX2_C_BIND )
                   1861: Return 1 if the system's C-language development facilities support the
                   1862: C-Language Bindings Option, otherwise 0.
                   1863: .It Li user.posix2_c_dev ( USER_POSIX2_C_DEV )
                   1864: Return 1 if the system supports the C-Language Development Utilities Option,
                   1865: otherwise 0.
                   1866: .It Li user.posix2_fort_dev ( USER_POSIX2_FORT_DEV )
                   1867: Return 1 if the system supports the FORTRAN Development Utilities Option,
                   1868: otherwise 0.
                   1869: .It Li user.posix2_fort_run ( USER_POSIX2_FORT_RUN )
                   1870: Return 1 if the system supports the FORTRAN Runtime Utilities Option,
                   1871: otherwise 0.
                   1872: .It Li user.posix2_localedef ( USER_POSIX2_LOCALEDEF )
                   1873: Return 1 if the system supports the creation of locales, otherwise 0.
                   1874: .It Li user.posix2_sw_dev ( USER_POSIX2_SW_DEV )
                   1875: Return 1 if the system supports the Software Development Utilities Option,
                   1876: otherwise 0.
                   1877: .It Li user.posix2_upe ( USER_POSIX2_UPE )
                   1878: Return 1 if the system supports the User Portability Utilities Option,
                   1879: otherwise 0.
                   1880: .It Li user.posix2_version ( USER_POSIX2_VERSION )
                   1881: The version of POSIX 1003.2 with which the system attempts to comply.
                   1882: .It Li user.re_dup_max ( USER_RE_DUP_MAX )
                   1883: The maximum number of repeated occurrences of a regular expression
                   1884: permitted when using interval notation.
                   1885: .It Li user.stream_max ( USER_STREAM_MAX )
                   1886: The minimum maximum number of streams that a process may have open
                   1887: at any one time.
                   1888: .It Li user.tzname_max ( USER_TZNAME_MAX )
                   1889: The minimum maximum number of types supported for the name of a
                   1890: timezone.
                   1891: .El
                   1892: .Sh The vm.* subtree ( CTL_VM )
                   1893: The string and integer information available for the
                   1894: .Li vm
                   1895: level is detailed below.
                   1896: The changeable column shows whether a process with appropriate
                   1897: privilege may change the value.
1.21      joerg    1898: .Bl -column "Second level name" "struct uvmexp_sysctl" "Changeable" -offset indent
1.1       pavel    1899: .It Sy Second level name       Type    Changeable
                   1900: .It vm.anonmax int     yes
                   1901: .It vm.anonmin int     yes
                   1902: .It vm.bufcache        int     yes
                   1903: .It vm.bufmem  int     no
                   1904: .It vm.bufmem_hiwater  int     yes
                   1905: .It vm.bufmem_lowater  int     yes
                   1906: .It vm.execmax int     yes
                   1907: .It vm.execmin int     yes
                   1908: .It vm.filemax int     yes
                   1909: .It vm.filemin int     yes
                   1910: .It vm.loadavg struct loadavg  no
                   1911: .It vm.maxslp  int     no
                   1912: .It vm.nkmempages      int     no
                   1913: .It vm.uspace  int     no
                   1914: .It vm.uvmexp  struct uvmexp   no
                   1915: .It vm.uvmexp2 struct uvmexp_sysctl    no
                   1916: .It vm.vmmeter struct vmtotal  no
                   1917: .El
                   1918: .Pp
                   1919: .Bl -tag -width "123456"
                   1920: .It Li vm.anonmax ( VM_ANONMAX )
                   1921: The percentage of physical memory which will be reclaimed
                   1922: from other types of memory usage to store anonymous application data.
                   1923: .It Li vm.anonmin ( VM_ANONMIN )
                   1924: The percentage of physical memory which will be always be available for
                   1925: anonymous application data.
                   1926: .It Li vm.bufcache ( VM_BUFCACHE )
                   1927: The percentage of physical memory which will be available
                   1928: for the buffer cache.
                   1929: .It Li vm.bufmem ( VM_BUFMEM )
                   1930: The amount of kernel memory that is being used by the buffer cache.
                   1931: .It Li vm.bufmem_lowater ( VM_BUFMEM_LOWATER )
                   1932: The minimum amount of kernel memory to reserve for the
                   1933: buffer cache.
                   1934: .It Li vm.bufmem_hiwater ( VM_BUFMEM_HIWATER )
                   1935: The maximum amount of kernel memory to be used for the
                   1936: buffer cache.
                   1937: .It Li vm.execmax ( VM_EXECMAX )
                   1938: The percentage of physical memory which will be reclaimed
                   1939: from other types of memory usage to store cached executable data.
                   1940: .It Li vm.execmin ( VM_EXECMIN )
                   1941: The percentage of physical memory which will be always be available for
                   1942: cached executable data.
                   1943: .It Li vm.filemax ( VM_FILEMAX )
                   1944: The percentage of physical memory which will be reclaimed
                   1945: from other types of memory usage to store cached file data.
                   1946: .It Li vm.filemin ( VM_FILEMIN )
                   1947: The percentage of physical memory which will be always be available for
                   1948: cached file data.
                   1949: .It Li vm.loadavg ( VM_LOADAVG )
                   1950: Return the load average history.
                   1951: The returned data consists of a
                   1952: .Va struct loadavg .
                   1953: .It Li vm.maxslp ( VM_MAXSLP )
                   1954: The value of the maxslp kernel global variable.
                   1955: .It Li vm.vmmeter ( VM_METER )
                   1956: Return system wide virtual memory statistics.
                   1957: The returned data consists of a
                   1958: .Va struct vmtotal .
1.31      drochner 1959: .It vm.user_va0_disable
                   1960: A flag which controls whether user processes can map virtual address 0.
1.1       pavel    1961: .It Li vm.uspace ( VM_USPACE )
                   1962: The number of bytes allocated for each kernel stack.
                   1963: .It Li vm.uvmexp ( VM_UVMEXP )
                   1964: Return system wide virtual memory statistics.
                   1965: The returned data consists of a
                   1966: .Va struct uvmexp .
                   1967: .It Li vm.uvmexp2 ( VM_UVMEXP2 )
                   1968: Return system wide virtual memory statistics.
                   1969: The returned data consists of a
                   1970: .Va struct uvmexp_sysctl .
                   1971: .\" XXX vm.idlezero
                   1972: .El
                   1973: .Sh The ddb.* subtree ( CTL_DDB )
1.34      jruoho   1974: The information available for the
1.1       pavel    1975: .Li ddb
                   1976: level is detailed below.
                   1977: The changeable column shows whether a process with appropriate
                   1978: privilege may change the value.
                   1979: .\" XXX sort
1.21      joerg    1980: .Bl -column "Second level name" "integer" "Changeable" -offset indent
1.1       pavel    1981: .It Sy Second level name       Type    Changeable
                   1982: .It ddb.radix  integer yes
                   1983: .It ddb.maxoff integer yes
1.34      jruoho   1984: .It ddb.maxwidth       integer yes
1.1       pavel    1985: .It ddb.lines  integer yes
                   1986: .It ddb.tabstops       integer yes
                   1987: .It ddb.onpanic        integer yes
                   1988: .It ddb.fromconsole    integer yes
1.34      jruoho   1989: .It ddb.tee_msgbuf     integer yes
                   1990: .It ddb.commandonenter string  yes
1.1       pavel    1991: .El
                   1992: .Pp
                   1993: .Bl -tag -width "123456"
1.35      jruoho   1994: .It Li ddb.radix ( DDBCTL_RADIX )
1.1       pavel    1995: The input and output radix.
1.35      jruoho   1996: .It Li ddb.maxoff ( DDBCTL_MAXOFF )
1.1       pavel    1997: The maximum symbol offset.
1.34      jruoho   1998: .It Li ddb.maxwidth ( DDBCTL_MAXWIDTH )
                   1999: The maximum output line width.
1.35      jruoho   2000: .It Li ddb.lines ( DDBCTL_LINES )
1.1       pavel    2001: Number of display lines.
1.35      jruoho   2002: .It Li ddb.tabstops ( DDBCTL_TABSTOPS )
1.1       pavel    2003: Tab width.
1.35      jruoho   2004: .It Li ddb.onpanic ( DDBCTL_ONPANIC )
1.18      ad       2005: If non-zero, DDB will be entered if the kernel panics.
1.35      jruoho   2006: .It Li ddb.fromconsole ( DDBCTL_FROMCONSOLE )
1.1       pavel    2007: If not zero, DDB may be entered by sending a break on a serial
                   2008: console or by a special key sequence on a graphics console.
1.34      jruoho   2009: .It Li ddb.tee_msgbuf
                   2010: If not zero, DDB will output also to the kernel message buffer.
                   2011: .It Li ddb.commandonenter
                   2012: If not empty, a command to be executed on each enter to the
                   2013: .Tn DDB .
                   2014: .\"
                   2015: .\" XXX: (a) ddb.commandonenter is missing in ddb(4);
                   2016: .\"     (b) No DDBCTL definitions for tee_msgbuf and commandonenter.
1.1       pavel    2017: .El
                   2018: .Pp
1.34      jruoho   2019: Some of these
                   2020: .Tn MIB
                   2021: nodes are also available as variables from within the debugger.
1.1       pavel    2022: See
                   2023: .Xr ddb 4
                   2024: for more details.
                   2025: .Sh The security.* subtree ( CTL_SECURITY )
                   2026: The
                   2027: .Li security
                   2028: level contains various security-related settings for
1.2       wiz      2029: the system.
                   2030: Available settings are detailed below.
1.1       pavel    2031: .Pp
                   2032: .Bl -tag -width "123456"
                   2033: .It Li security.curtain
                   2034: If non-zero, will filter return objects according to the user-id
                   2035: requesting information about them, preventing from users any
                   2036: access to objects they don't own.
                   2037: .Pp
                   2038: At the moment, it affects
                   2039: .Xr ps 1 ,
                   2040: .Xr netstat 1
                   2041: (for
                   2042: .Dv PF_INET ,
                   2043: .Dv PF_INET6 ,
                   2044: and
                   2045: .Dv PF_UNIX
                   2046: PCBs), and
                   2047: .Xr w 1 .
1.4       elad     2048: .It Li security.models
                   2049: .Nx
                   2050: supports pluggable security models.
1.17      ad       2051: Every security model used, whether if loaded as a module or built with the system,
1.4       elad     2052: is required to add an entry to this node with at least one element,
                   2053: .Dq name ,
                   2054: indicating the name of the security model.
                   2055: .Pp
                   2056: In addition to the name, any settings and other information private to the
                   2057: security model will be available under this node.
                   2058: See
                   2059: .Xr secmodel 9
                   2060: for more information.
1.1       pavel    2061: .It Li security.pax
                   2062: Settings for PaX -- exploit mitigation features.
1.4       elad     2063: For more information on any of the PaX features, please see
                   2064: .Xr paxctl 8
                   2065: and
                   2066: .Xr security 8 .
1.1       pavel    2067: .Pp
                   2068: .Bl -tag -width "123456"
1.14      elad     2069: .It Li security.pax.aslr.enable
                   2070: Enable PaX ASLR (Address Space Layout Randomization).
                   2071: .Pp
                   2072: The value of this
                   2073: knob must be non-zero for PaX ASLR to be enabled, even if a program is set to
                   2074: explicit enable.
                   2075: .It Li security.pax.aslr.global
                   2076: Specifies the default global policy for programs without an
                   2077: explicit enable/disable flag.
                   2078: .Pp
                   2079: When non-zero, all programs will get PaX ASLR, except those exempted with
                   2080: .Xr paxctl 8  .
                   2081: Otherwise, all programs will not get PaX ASLR, except those specifically
                   2082: marked as such with
                   2083: .Xr paxctl 8 .
1.1       pavel    2084: .It Li security.pax.mprotect.enable
                   2085: Enable PaX MPROTECT restrictions.
                   2086: .Pp
                   2087: These are
                   2088: .Xr mprotect 2
1.2       wiz      2089: restrictions to better enforce a W^X policy.
                   2090: The value of this
1.1       pavel    2091: knob must be non-zero for PaX MPROTECT to be enabled, even if a
                   2092: program is set to explicit enable.
                   2093: .It Li security.pax.mprotect.global
                   2094: Specifies the default global policy for programs without an
                   2095: explicit enable/disable flag.
                   2096: .Pp
                   2097: When non-zero, all programs will get the PaX MPROTECT restrictions,
                   2098: except those exempted with
1.4       elad     2099: .Xr paxctl 8  .
1.1       pavel    2100: Otherwise, all programs will not get the PaX MPROTECT restrictions,
                   2101: except those specifically marked as such with
1.4       elad     2102: .Xr paxctl 8 .
1.1       pavel    2103: .It Li security.pax.segvguard.enable
                   2104: Enable PaX Segvguard.
                   2105: .Pp
                   2106: PaX Segvguard can detect and prevent certain exploitation attempts, where
                   2107: an attacker may try for example to brute-force function return addresses
                   2108: of respawning daemons.
                   2109: .Pp
                   2110: .Em Note :
                   2111: The
                   2112: .Nx
                   2113: interface and implementation of the Segvguard is still experimental, and may
                   2114: change in future releases.
                   2115: .It Li security.pax.segvguard.global
                   2116: Specifies the default global policy for programs without an
                   2117: explicit enable/disable flag.
                   2118: .Pp
                   2119: When non-zero, all programs will get the PaX Segvguard,
                   2120: except those exempted with
1.4       elad     2121: .Xr paxctl 8  .
1.2       wiz      2122: Otherwise, no program will get the PaX Segvguard restrictions,
1.1       pavel    2123: except those specifically marked as such with
1.4       elad     2124: .Xr paxctl 8 .
1.1       pavel    2125: .It Li security.pax.segvguard.expiry_timeout
                   2126: If the max number was not reached within this timeout (in seconds), the entry
                   2127: will expire.
                   2128: .It Li security.pax.segvguard.suspend_timeout
                   2129: Number of seconds to suspend a user from running a faulting program when the
                   2130: limit was exceeded.
                   2131: .It Li security.pax.segvguard.max_crashes
                   2132: Max number of segfaults a program can receive before suspension.
                   2133: .El
                   2134: .El
                   2135: .Sh The vendor.* subtree ( CTL_VENDOR )
                   2136: The
                   2137: .Li vendor
                   2138: toplevel name is reserved to be used by vendors who wish to
                   2139: have their own private MIB tree.
                   2140: Intended use is to store values under
                   2141: .Dq vendor.\*[Lt]yourname\*[Gt].* .
                   2142: .Sh SEE ALSO
                   2143: .Xr sysctl 3 ,
                   2144: .Xr ipsec 4 ,
                   2145: .Xr tcp 4 ,
                   2146: .Xr security 8 ,
                   2147: .Xr sysctl 8
                   2148: .Sh HISTORY
                   2149: The
                   2150: .Nm
                   2151: variables first appeared in
                   2152: .Bx 4.4 .

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