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1.6     ! liamjfoy    1: .\"    $NetBSD: sysctl.7,v 1.5 2007/03/07 22:24:31 liamjfoy Exp $
1.1       pavel       2: .\"
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                     30: .\"    @(#)sysctl.3    8.4 (Berkeley) 5/9/95
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1.4       elad       32: .Dd February 2, 2007
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
                     73: .Aq Pa sys/sysctl.h ,
                     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.
                     77: .Bl -column securityXX CTLXSECURITYXX "Next level namesXX"
                     78: .It Sy Name    Constant        Next level names        Description
                     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
                     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.
                    134: One of its third level identifiers is
                    135: .Li vfs.generic.maxtypenum ( VFS_MAXTYPENUM )
                    136: that gives the highest valid filesystem type number.
                    137: Its other third level identifier is
                    138: .Li vfs.generic.conf ( VFS_CONF )
                    139: that returns configuration information about the filesystem
                    140: type given as a fourth level identifier.
                    141: The remaining second level identifiers are the
                    142: filesystem type number returned by a
                    143: .Xr statvfs 2
                    144: call or from
                    145: .Li vfs.generic.conf .
                    146: The third level identifiers available for each filesystem
                    147: are given in the header file that defines the mount
                    148: argument structure for that filesystem.
                    149: .Sh The hw.* subtree
                    150: The string and integer information available for the
                    151: .Li hw
                    152: level is detailed below.
                    153: The changeable column shows whether a process with appropriate
                    154: privilege may change the value.
                    155: .Bl -column "Second level nameXXXXXX" "struct disk_sysctlXXX" -offset indent
                    156: .It Sy Second level name       Type    Changeable
                    157: .It hw.alignbytes      integer no
                    158: .It hw.byteorder       integer no
                    159: .It hw.cnmagic string  yes
                    160: .It hw.disknames       string  no
                    161: .It hw.diskstats       struct  no
                    162: .It hw.machine string  no
                    163: .It hw.machine_arch    string  no
                    164: .It hw.model   string  no
                    165: .It hw.ncpu    integer no
                    166: .It hw.pagesize        integer no
                    167: .It hw.physmem integer no
                    168: .It hw.physmem64       quad    no
                    169: .It hw.usermem integer no
                    170: .It hw.usermem64       quad    no
                    171: .El
                    172: .Pp
                    173: .Bl -tag -width "123456"
                    174: .It Li hw.alignbytes ( HW_ALIGNBYTES )
                    175: Alignment constraint for all possible data types.
                    176: This shows the value
                    177: .Dv ALIGNBYTES
                    178: in
                    179: .Pa /usr/include/machine/param.h ,
                    180: at the kernel compilation time.
                    181: .It Li hw.byteorder ( HW_BYTEORDER )
                    182: The byteorder (4,321, or 1,234).
                    183: .It Li hw.cnmagic ( HW_CNMAGIC )
                    184: The console magic key sequence.
                    185: .It Li hw.disknames ( HW_DISKNAMES )
                    186: The list of (space separated) disk device names on the system.
                    187: .It Li hw.iostatnames ( HW_IOSTATNAMES )
                    188: A space separated list of devices that will have I/O statistics
                    189: collected on them.
                    190: .It Li hw.iostats ( HW_IOSTATS )
                    191: Return statistical information on the NFS mounts, disk and tape
                    192: devices on the system.
                    193: An array of
                    194: .Va struct io_sysctl
                    195: structures is returned,
                    196: whose size depends on the current number of such objects in the system.
                    197: The third level name is the size of the
                    198: .Va struct io_sysctl .
                    199: The type of object can be determined by examining the
                    200: .Va type
                    201: element of
                    202: .Va struct io_sysctl .
                    203: Which can be
                    204: .Dv IOSTAT_DISK
                    205: (disk drive),
                    206: .Dv IOSTAT_TAPE
                    207: (tape drive), or
                    208: .Dv IOSTAT_NFS
                    209: (NFS mount).
                    210: .It Li hw.machine ( HW_MACHINE )
                    211: The machine class.
                    212: .It Li hw.machine_arch ( HW_MACHINE_ARCH )
                    213: The machine CPU class.
                    214: .It Li hw.model ( HW_MODEL )
                    215: The machine model.
                    216: .It Li hw.ncpu ( HW_NCPU )
                    217: The number of CPUs.
                    218: .ne 1i
                    219: .It Li hw.pagesize ( HW_PAGESIZE )
                    220: The software page size.
                    221: .It Li hw.physmem ( HW_PHYSMEM )
                    222: The bytes of physical memory as a 32-bit integer.
                    223: .It Li hw.physmem64 ( HW_PHYSMEM64 )
                    224: The bytes of physical memory as a 64-bit integer.
                    225: .It Li hw.usermem ( HW_USERMEM )
                    226: The bytes of non-kernel memory as a 32-bit integer.
                    227: .It Li hw.usermem64 ( HW_USERMEM64 )
                    228: The bytes of non-kernel memory as a 64-bit integer.
                    229: .El
                    230: .Sh The kern.* subtree
                    231: The string and integer information available for the
                    232: .Li kern
                    233: level is detailed below.
                    234: The changeable column shows whether a process with appropriate
                    235: privilege may change the value.
                    236: The types of data currently available are process information,
                    237: system vnodes, the open file entries, routing table entries,
                    238: virtual memory statistics, load average history, and clock rate
                    239: information.
                    240: .Bl -column "kern.posix_reader_writer_locks" "struct clockrateXXX" -offset indent
                    241: .It Sy Second level name       Type    Changeable
                    242: .It kern.argmax        integer no
                    243: .It kern.autonicetime  integer yes
                    244: .It kern.autoniceval   integer yes
                    245: .It kern.boottime      struct timeval  no
                    246: .It kern.bufq  node    not applicable
                    247: .It kern.ccpu  integer no
                    248: .It kern.clockrate     struct clockinfo        no
                    249: .It kern.consdev       integer no
                    250: .It kern.cp\_id        struct  no
                    251: .It kern.cp\_time      uint64_t[\|]    no
                    252: .It kern.defcorename   string  yes
                    253: .It kern.domainname    string  yes
                    254: .It kern.drivers       struct kinfo_drivers    no
                    255: .It kern.file  struct file     no
                    256: .It kern.forkfsleep    integer yes
                    257: .It kern.fscale        integer no
                    258: .It kern.fsync integer no
                    259: .It kern.hardclock\_ticks      integer no
                    260: .It kern.hostid        integer yes
                    261: .It kern.hostname      string  yes
                    262: .It kern.iov\_max      integer no
                    263: .It kern.job\_control  integer no
                    264: .It kern.labeloffset   integer no
                    265: .It kern.labelsector   integer no
                    266: .It kern.login\_name\_max      integer no
                    267: .It kern.logsigexit    integer yes
                    268: .It kern.mapped\_files integer no
                    269: .It kern.maxfiles      integer yes
                    270: .It kern.maxpartitions integer no
                    271: .It kern.maxphys       integer no
                    272: .It kern.maxproc       integer yes
                    273: .It kern.maxptys       integer yes
                    274: .It kern.maxvnodes     integer yes
                    275: .It kern.mbuf  node    not applicable
                    276: .It kern.memlock       integer no
                    277: .It kern.memlock\_range        integer no
                    278: .It kern.memory\_protection    integer no
                    279: .It kern.monotonic\_clock      integer no
                    280: .It kern.msgbuf        integer no
                    281: .It kern.msgbufsize    integer no
                    282: .It kern.ngroups       integer no
                    283: .It kern.ntptime       struct ntptimeval       no
                    284: .It kern.osrelease     string  no
                    285: .It kern.osrev integer no
                    286: .It kern.ostype        string  no
                    287: .It kern.pipe  node    not applicable
                    288: .It kern.posix1        integer no
                    289: .It kern.posix\_barriers       integer no
                    290: .It kern.posix\_reader\_writer\_locks  integer no
                    291: .It kern.posix\_semaphores     integer no
                    292: .It kern.posix\_spin\_locks    integer no
                    293: .It kern.posix\_threads        integer no
                    294: .It kern.posix\_timers integer no
                    295: .It kern.proc  struct kinfo_proc       no
                    296: .It kern.proc2 struct kinfo_proc2      no
                    297: .It kern.proc\_args    string  no
                    298: .It kern.prof  node    not applicable
                    299: .It kern.rawpartition  integer no
                    300: .It kern.root\_device  string  no
                    301: .It kern.root\_partition       integer no
                    302: .It kern.rtc\_offset   integer yes
                    303: .It kern.saved\_ids    integer no
                    304: .It kern.securelevel   integer raise only
                    305: .It kern.synchronized\_io      integer no
                    306: .It kern.ipc   node    not applicable
                    307: .It kern.timex struct  no
                    308: .It kern.tkstat        node    not applicable
                    309: .It kern.urandom       integer no
                    310: .It kern.version       string  no
                    311: .It kern.vnode struct vnode    no
                    312: .El
                    313: .ne 1i
                    314: .Pp
                    315: .Bl -tag -width "123456"
                    316: .It Li kern.argmax ( KERN_ARGMAX )
                    317: The maximum bytes of argument to
                    318: .Xr execve 2 .
                    319: .It Li kern.autonicetime ( KERN_AUTONICETIME )
                    320: The number of seconds of CPU-time a non-root process may accumulate before
                    321: having its priority lowered from the default to the value of KERN_AUTONICEVAL.
                    322: If set to 0, automatic lowering of priority is not performed, and if set to \-1
                    323: all non-root processes are immediately lowered.
                    324: .It Li kern.autoniceval ( KERN_AUTONICEVAL )
                    325: The priority assigned for automatically niced processes.
                    326: .It Li kern.boottime ( KERN_BOOTTIME )
                    327: A
                    328: .Va struct timeval
                    329: structure is returned.
                    330: This structure contains the time that the system was booted.
                    331: .It Li kern.ccpu ( KERN_CCPU )
                    332: The scheduler exponential decay value.
                    333: .It Li kern.clockrate ( KERN_CLOCKRATE )
                    334: A
                    335: .Va struct clockinfo
                    336: structure is returned.
                    337: This structure contains the clock, statistics clock and profiling clock
                    338: frequencies, the number of micro-seconds per hz tick, and the clock
                    339: skew rate.
                    340: .It Li kern.consdev ( KERN_CONSDEV )
                    341: Console device.
                    342: .It Li kern.cp_id ( KERN_CP_ID )
                    343: Mapping of CPU number to CPU id.
                    344: .It Li kern.cp_time ( KERN_CP_TIME )
                    345: Returns an array of CPUSTATES uint64_ts.
                    346: This array contains the
                    347: number of clock ticks spent in different CPU states.
                    348: On multi-processor systems, the sum across all CPUs is returned unless
                    349: appropriate space is given for one data set for each CPU.
                    350: Data for a specific CPU can also be obtained by adding the number of the
                    351: CPU at the end of the MIB, enlarging it by one.
                    352: .It Li kern.defcorename ( KERN_DEFCORENAME )
                    353: Default template for the name of core dump files (see also
                    354: .Li proc.pid.corename
                    355: in the per-process variables
                    356: .Li proc.* ,
                    357: and
                    358: .Xr core 5
                    359: for format of this template).
                    360: The default value is
                    361: .Nm %n.core
                    362: and can be changed with the kernel configuration option
                    363: .Cd options DEFCORENAME
                    364: (see
                    365: .Xr options 4
                    366: ).
                    367: .It Li kern.domainname ( KERN_DOMAINNAME )
                    368: Get or set the YP domain name.
                    369: .It Li kern.dump_on_panic ( KERN_DUMP_ON_PANIC )
                    370: Perform a crash dump on system panic.
                    371: .It Li kern.drivers ( KERN_DRIVERS )
                    372: Return an array of
                    373: .Va struct kinfo_drivers
                    374: that contains the name and major device numbers of all the device drivers
                    375: in the current kernel.
                    376: The
                    377: .Va d_name
                    378: field is always a NUL terminated string.
                    379: The
                    380: .Va d_bmajor
                    381: field will be set to \-1 if the driver doesn't have a block device.
                    382: .It Li kern.file ( KERN_FILE )
                    383: Return the entire file table.
                    384: The returned data consists of a single
                    385: .Va struct filelist
                    386: followed by an array of
                    387: .Va struct file ,
                    388: whose size depends on the current number of such objects in the system.
                    389: .It Li kern.forkfsleep ( KERN_FORKFSLEEP )
                    390: If
                    391: .Xr fork 2
                    392: system call fails due to limit on number of processes (either
                    393: the global maxproc limit or user's one), wait for this many
                    394: milliseconds before returning
                    395: .Er EAGAIN
                    396: error to process.
                    397: Useful to keep heavily forking runaway processes in bay.
                    398: Default zero (no sleep).
                    399: Maximum is 20 seconds.
                    400: .It Li kern.fscale ( KERN_FSCALE )
                    401: The kernel fixed-point scale factor.
                    402: .It Li kern.fsync ( KERN_FSYNC )
                    403: Return 1 if the POSIX 1003.1b File Synchronization Option is available
                    404: on this system,
                    405: otherwise 0.
                    406: .It Li kern.hardclock_ticks ( KERN_HARDCLOCK_TICKS )
                    407: Returns the number of
                    408: .Xr hardclock 9
                    409: ticks.
                    410: .It Li kern.hostid ( KERN_HOSTID )
                    411: Get or set the host id.
                    412: .It Li kern.hostname ( KERN_HOSTNAME )
                    413: Get or set the hostname.
                    414: .It Li kern.iov_max ( KERN_IOV_MAX )
                    415: Return the maximum number of
                    416: .Va iovec
                    417: structures that a process has available for use with
                    418: .Xr preadv 2 ,
                    419: .Xr pwritev 2 ,
                    420: .Xr readv 2 ,
                    421: .Xr recvmsg 2 ,
                    422: .Xr sendmsg 2
                    423: and
                    424: .Xr writev 2 .
                    425: .It Li kern.job_control ( KERN_JOB_CONTROL )
                    426: Return 1 if job control is available on this system, otherwise 0.
                    427: .It Li kern.labeloffset ( KERN_LABELOFFSET )
                    428: The offset within the sector specified by KERN_LABELSECTOR of the
                    429: .Xr disklabel 5 .
                    430: .It Li kern.labelsector ( KERN_LABELSECTOR )
                    431: The sector number containing the
                    432: .Xr disklabel 5 .
                    433: .It Li kern.login_name_max ( KERN_LOGIN_NAME_MAX )
                    434: The size of the storage required for a login name, in bytes,
                    435: including the terminating NUL.
                    436: .It Li kern.logsigexit ( KERN_LOGSIGEXIT )
                    437: If this flag is non-zero, the kernel will
                    438: .Xr log 9
                    439: all process exits due to signals which create a
                    440: .Xr core 5
                    441: file, and whether the coredump was created.
                    442: .It Li kern.mapped_files ( KERN_MAPPED_FILES )
                    443: Returns 1 if the POSIX 1003.1b Memory Mapped Files Option is available
                    444: on this system,
                    445: otherwise 0.
                    446: .It Li kern.maxfiles ( KERN_MAXFILES )
                    447: The maximum number of open files that may be open in the system.
                    448: .It Li kern.maxpartitions ( KERN_MAXPARTITIONS )
                    449: The maximum number of partitions allowed per disk.
                    450: .It Li kern.maxphys ( KERN_MAXPHYS )
                    451: Maximum raw I/O transfer size.
                    452: .It Li kern.maxproc ( KERN_MAXPROC )
                    453: The maximum number of simultaneous processes the system will allow.
                    454: .It Li kern.maxptys ( KERN_MAXPTYS )
                    455: The maximum number of pseudo terminals.
                    456: This value can be both raised and lowered, though it cannot
                    457: be set lower than number of currently used ptys.
                    458: See also
                    459: .Xr pty 4 .
                    460: .It Li kern.maxvnodes ( KERN_MAXVNODES )
                    461: The maximum number of vnodes available on the system.
                    462: This can only be raised.
                    463: .It Li kern.mbuf ( KERN_MBUF )
                    464: Return information about the mbuf control variables.
                    465: Mbufs are data structures which store network packets and other data
                    466: structures in the networking code, see
                    467: .Xr mbuf 9 .
                    468: The third level names for the mbuf variables are detailed below.
                    469: The changeable column shows whether a process with appropriate
                    470: privilege may change the value.
                    471: .Bl -column "kern.mbuf.nmbclusters" "struct integerXXX" -offset indent
                    472: .It Sy Third level name        Type    Changeable
                    473: .\" XXX Changeable? really?
                    474: .It kern.mbuf.mblowat  integer yes
                    475: .It kern.mbuf.mclbytes integer yes
                    476: .It kern.mbuf.mcllowat integer yes
                    477: .It kern.mbuf.msize    integer yes
                    478: .It kern.mbuf.nmbclusters      integer yes
                    479: .El
                    480: .Pp
                    481: The variables are as follows:
                    482: .Bl -tag -width "123456"
                    483: .It Li kern.mbuf.mblowat ( MBUF_MBLOWAT )
                    484: The mbuf low water mark.
                    485: .It Li kern.mbuf.mclbytes ( MBUF_MCLBYTES )
                    486: The mbuf cluster size.
                    487: .It Li kern.mbuf.mcllowat ( MBUF_MCLLOWAT )
                    488: The mbuf cluster low water mark.
                    489: .It Li kern.mbuf.msize ( MBUF_MSIZE )
                    490: The mbuf base size.
                    491: .It Li kern.mbuf.nmbclusters ( MBUF_NMBCLUSTERS )
                    492: The limit on the number of mbuf clusters.
                    493: The variable can only be increased, and only increased on machines with
                    494: direct-mapped pool pages.
                    495: .El
                    496: .It Li kern.memlock ( KERN_MEMLOCK )
                    497: Returns 1 if the POSIX 1003.1b Process Memory Locking Option is available
                    498: on this system,
                    499: otherwise 0.
                    500: .It Li kern.memlock_range ( KERN_MEMLOCK_RANGE )
                    501: Returns 1 if the POSIX 1003.1b Range Memory Locking Option is available
                    502: on this system,
                    503: otherwise 0.
                    504: .It Li kern.memory_protection ( KERN_MEMORY_PROTECTION )
                    505: Returns 1 if the POSIX 1003.1b Memory Protection Option is available
                    506: on this system,
                    507: otherwise 0.
                    508: .It Li kern.monotonic_clock ( KERN_MONOTONIC_CLOCK )
                    509: Returns the standard version the implementation of the POSIX 1003.1b
                    510: Monotonic Clock Option conforms to,
                    511: otherwise 0.
                    512: .It Li kern.msgbuf ( KERN_MSGBUF )
                    513: The kernel message buffer, rotated so that the head of the circular kernel
                    514: message buffer is at the start of the returned data.
                    515: The returned data may contain NUL bytes.
                    516: .It Li kern.msgbufsize ( KERN_MSGBUFSIZE )
                    517: The maximum number of characters that the kernel message buffer can hold.
                    518: .It Li kern.ngroups ( KERN_NGROUPS )
                    519: The maximum number of supplemental groups.
                    520: .It Li kern.ntptime ( KERN_NTPTIME )
                    521: A
                    522: .Va struct ntptimeval
                    523: structure is returned.
                    524: This structure contains data used by the
                    525: .Xr ntpd 8
                    526: program.
                    527: .It Li kern.osrelease ( KERN_OSRELEASE )
                    528: The system release string.
                    529: .It Li kern.osrevision ( KERN_OSREV )
                    530: The system revision string.
                    531: .It Li kern.ostype ( KERN_OSTYPE )
                    532: The system type string.
                    533: .It Li kern.pipe ( KERN_PIPE )
                    534: Pipe settings.
                    535: The third level names for the  integer pipe settings is detailed below.
                    536: The changeable column shows whether a process with appropriate
                    537: privilege may change the value.
                    538: .Bl -column "kern.pipe.maxbigpipesXXX" "integerXXX" -offset indent
                    539: .It Sy Third level name        Type    Changeable
                    540: .It kern.pipe.kvasiz   integer yes
                    541: .It kern.pipe.maxbigpipes      integer yes
                    542: .It kern.pipe.maxkvasz integer yes
                    543: .It kern.pipe.limitkva integer yes
                    544: .It kern.pipe.nbigpipes        integer yes
                    545: .El
                    546: .Pp
                    547: The variables are as follows:
                    548: .Bl -tag -width "123456"
                    549: .It Li kern.pipe.kvasiz ( KERN_PIPE_KVASIZ )
                    550: Amount of kernel memory consumed by pipe buffers.
                    551: .It Li kern.pipe.maxbigpipes ( KERN_PIPE_MAXBIGPIPES )
                    552: Maximum number of "big" pipes.
                    553: .It Li kern.pipe.maxkvasz ( KERN_PIPE_MAXKVASZ )
                    554: Maximum amount of kernel memory to be used for pipes.
                    555: .It Li kern.pipe.limitkva ( KERN_PIPE_LIMITKVA )
                    556: Limit for direct transfers via page loan.
                    557: .It Li kern.pipe.nbigpipes ( KERN_PIPE_NBIGPIPES )
                    558: Number of "big" pipes.
                    559: .El
                    560: .It Li kern.posix1version ( KERN_POSIX1 )
                    561: The version of ISO/IEC 9945 (POSIX 1003.1) with which the system
                    562: attempts to comply.
                    563: .It Li kern.posix_barriers ( KERN_POSIX_BARRIERS )
                    564: The version of
                    565: .St -p1003.1
                    566: and its
                    567: Barriers
                    568: option to which the system attempts to conform,
                    569: otherwise 0.
                    570: .It Li kern.posix_reader_writer_locks ( KERN_POSIX_READER_WRITER_LOCKS )
                    571: The version of
                    572: .St -p1003.1
                    573: and its
                    574: Read-Write Locks
                    575: option to which the system attempts to conform,
                    576: otherwise 0.
                    577: .It Li kern.posix_semaphores ( KERN_POSIX_SEMAPHORES )
                    578: The version of
                    579: .St -p1003.1
                    580: and its
                    581: Semaphores
                    582: option to which the system attempts to conform,
                    583: otherwise 0.
                    584: .It Li kern.posix_spin_locks ( KERN_POSIX_SPIN_LOCKS )
                    585: The version of
                    586: .St -p1003.1
                    587: and its
                    588: Spin Locks
                    589: option to which the system attempts to conform,
                    590: otherwise 0.
                    591: .It Li kern.posix_threads ( KERN_POSIX_THREADS )
                    592: The version of
                    593: .St -p1003.1
                    594: and its
                    595: Threads
                    596: option to which the system attempts to conform,
                    597: otherwise 0.
                    598: .It Li kern.posix_timers ( KERN_POSIX_TIMERS )
                    599: The version of
                    600: .St -p1003.1
                    601: and its
                    602: Timers
                    603: option to which the system attempts to conform,
                    604: otherwise 0.
                    605: .It Li kern.proc ( KERN_PROC )
                    606: Return the entire process table, or a subset of it.
                    607: An array of
                    608: .Va struct kinfo_proc
                    609: structures is returned,
                    610: whose size depends on the current number of such objects in the system.
                    611: The third and fourth level numeric names are as follows:
                    612: .Bl -column "Third level nameXXXXXX" "Fourth level is:XXXXXX" -offset indent
                    613: .It Sy Third level name        Fourth level is:
                    614: .It KERN\_PROC\_ALL    None
                    615: .It KERN\_PROC\_GID    A group ID
                    616: .It KERN\_PROC\_PID    A process ID
                    617: .It KERN\_PROC\_PGRP   A process group
                    618: .It KERN\_PROC\_RGID   A real group ID
                    619: .It KERN\_PROC\_RUID   A real user ID
                    620: .It KERN\_PROC\_SESSION        A session ID
                    621: .It KERN\_PROC\_TTY    A tty device
                    622: .It KERN\_PROC\_UID    A user ID
                    623: .El
                    624: .It Li kern.proc2 ( KERN_PROC2 )
                    625: As for KERN_PROC, but an array of
                    626: .Va struct kinfo_proc2
                    627: structures are returned.
                    628: The fifth level name is the size of the
                    629: .Va struct kinfo_proc2
                    630: and the sixth level name is the number of structures to return.
                    631: .It Li kern.proc_args ( KERN_PROC_ARGS )
                    632: Return the argv or environment strings (or the number thereof)
                    633: of a process.
                    634: Multiple strings are returned separated by NUL characters.
                    635: The third level name is the process ID.
                    636: The fourth level name is as follows:
                    637: .Bl -column "Third level nameXXXXXX" -offset indent
                    638: .It KERN\_PROC\_ARGV   The argv strings
                    639: .It KERN\_PROC\_ENV    The environ strings
                    640: .It KERN\_PROC\_NARGV  The number of argv strings
                    641: .It KERN\_PROC\_NENV   The number of environ strings
                    642: .El
                    643: .It Li kern.profiling ( KERN_PROF )
                    644: Return profiling information about the kernel.
                    645: If the kernel is not compiled for profiling,
                    646: attempts to retrieve any of the KERN_PROF values will
                    647: fail with
                    648: .Er EOPNOTSUPP .
                    649: The third level names for the string and integer profiling information
                    650: is detailed below.
                    651: The changeable column shows whether a process with appropriate
                    652: privilege may change the value.
                    653: .Bl -column "kern.profiling.gmonparam" "struct gmonparam" -offset indent
                    654: .It Sy Third level name        Type    Changeable
                    655: .It kern.profiling.count       u_short[\|]     yes
                    656: .It kern.profiling.froms       u_short[\|]     yes
                    657: .It kern.profiling.gmonparam   struct gmonparam        no
                    658: .It kern.profiling.state       integer yes
                    659: .It kern.profiling.tos struct tostruct yes
                    660: .El
                    661: .Pp
                    662: The variables are as follows:
                    663: .Bl -tag -width "123456"
                    664: .It Li kern.profiling.count ( GPROF_COUNT )
                    665: Array of statistical program counter counts.
                    666: .It Li kern.profiling.froms ( GPROF_FROMS )
                    667: Array indexed by program counter of call-from points.
                    668: .It Li kern.profiling.gmonparams ( GPROF_GMONPARAM )
                    669: Structure giving the sizes of the above arrays.
                    670: .It Li kern.profiling.state ( GPROF_STATE )
                    671: Profiling state.
                    672: If set to GMON_PROF_ON, starts profiling.
                    673: If set to GMON_PROF_OFF, stops profiling.
                    674: .It Li kern.profiling.tos ( GPROF_TOS )
                    675: Array of
                    676: .Va struct tostruct
                    677: describing destination of calls and their counts.
                    678: .El
                    679: .It Li kern.rawpartition ( KERN_RAWPARTITION )
                    680: The raw partition of a disk (a == 0).
                    681: .It Li kern.root_device ( KERN_ROOT_DEVICE )
                    682: The name of the root device (e.g.,
                    683: .Dq wd0 ) .
                    684: .It Li kern.root_partition ( KERN_ROOT_PARTITION )
                    685: The root partition on the root device (a == 0).
                    686: .It Li kern.rtc_offset ( KERN_RTC_OFFSET )
                    687: Return the offset of real time clock from UTC in minutes.
                    688: .It Li kern.saved_ids ( KERN_SAVED_IDS )
                    689: Returns 1 if saved set-group and saved set-user ID is available.
                    690: .It Li kern.sbmax ( KERN_SBMAX )
                    691: Maximum socket buffer size.
                    692: .\" XXX units?
                    693: .It Li kern.securelevel ( KERN_SECURELVL )
                    694: The system security level.
                    695: This level may be raised by processes with appropriate privilege.
                    696: It may only be lowered by process 1.
                    697: .It Li kern.somaxkva ( KERN_SOMAXKVA )
                    698: Maximum amount of kernel memory to be used for socket buffers.
                    699: .\" XXX units?
                    700: .It Li kern.synchronized_io ( KERN_SYNCHRONIZED_IO )
                    701: Returns 1 if the POSIX 1003.1b Synchronized I/O Option is available
                    702: on this system,
                    703: otherwise 0.
                    704: .It Li kern.ipc ( KERN_SYSVIPC )
1.2       wiz       705: Return information about the SysV IPC parameters.
                    706: The third level names for the ipc variables are detailed below.
1.1       pavel     707: .Bl -column "KERN_SYSVIPC_MSGXXX" "integerXXX" "noXXX" -offset indent
                    708: .It Sy Third level name        Type            Changeable
                    709: .It kern.ipc.sysvmsg   integer         no
                    710: .It kern.ipc.sysvsem   integer         no
                    711: .It kern.ipc.sysvshm   integer         no
                    712: .It kern.ipc.sysvipc_info      struct          no
                    713: .It kern.ipc.shmmax    integer         no
                    714: .It kern.ipc.shmmni    integer         yes
                    715: .It kern.ipc.shmseg    integer         yes
                    716: .It kern.ipc.shmmaxpgs integer         yes
                    717: .It kern.ipc.shm_use_phys      integer         yes
                    718: .El
                    719: .Bl -tag -width "123456"
                    720: .It Li kern.ipc.sysvmsg ( KERN_SYSVIPC_MSG )
                    721: Returns 1 if System V style message queue functionality is available
                    722: on this system,
                    723: otherwise 0.
                    724: .It Li kern.ipc.sysvsem ( KERN_SYSVIPC_SEM )
                    725: Returns 1 if System V style semaphore functionality is available
                    726: on this system,
                    727: otherwise 0.
                    728: .It Li kern.ipc.sysvshm ( KERN_SYSVIPC_SHM )
                    729: Returns 1 if System V style share memory functionality is available
                    730: on this system,
                    731: otherwise 0.
                    732: .It Li kern.ipc.sysvipc_info ( KERN_SYSVIPC_INFO )
                    733: Return System V style IPC configuration and run-time information.
                    734: The fourth level name selects the System V style IPC facility.
                    735: .Bl -column "KERN_SYSVIPC_MSG_INFOXXX" "struct shm_sysctl_infoXXX" -offset indent
                    736: .It Sy Fourth level name       Type
                    737: .It KERN\_SYSVIPC\_MSG\_INFO   struct msg_sysctl_info
                    738: .It KERN\_SYSVIPC\_SEM\_INFO   struct sem_sysctl_info
                    739: .It KERN\_SYSVIPC\_SHM\_INFO   struct shm_sysctl_info
                    740: .El
                    741: .Pp
                    742: .Bl -tag -width "123456"
                    743: .It Li KERN_SYSVIPC_MSG_INFO
                    744: Return information on the System V style message facility.
                    745: The
                    746: .Sy msg_sysctl_info
                    747: structure is defined in
                    748: .Aq Pa sys/msg.h .
                    749: .It Li KERN_SYSVIPC_SEM_INFO
                    750: Return information on the System V style semaphore facility.
                    751: The
                    752: .Sy sem_sysctl_info
                    753: structure is defined in
                    754: .Aq Pa sys/sem.h .
                    755: .It Li KERN_SYSVIPC_SHM_INFO
                    756: Return information on the System V style shared memory facility.
                    757: The
                    758: .Sy shm_sysctl_info
                    759: structure is defined in
                    760: .Aq Pa sys/shm.h .
                    761: .El
                    762: .It Li kern.ipc.shmmax ( KERN_SYSVIPC_SHMMAX )
                    763: Max shared memory segment size in bytes.
                    764: .It Li kern.ipc.shmmni ( KERN_SYSVIPC_SHMMNI )
                    765: Max number of shared memory identifiers.
                    766: .It Li kern.ipc.shmseg ( KERN_SYSVIPC_SHMSEG )
                    767: Max shared memory segments per process.
                    768: .It Li kern.ipc.shmmaxpgs ( KERN_SYSVIPC_SHMMAXPGS )
                    769: Max amount of shared memory in pages.
                    770: .It Li kern.ipc.shm_use_phys ( KERN_SYSVIPC_SHMUSEPHYS )
1.2       wiz       771: Locking of shared memory in physical memory.
1.3       wiz       772: If 0, memory can be swapped
1.1       pavel     773: out, otherwise it will be locked in physical memory.
                    774: .El
                    775: .It Li kern.timex ( KERN_TIMEX )
                    776: Not available.
                    777: .It Li kern.tkstat ( KERN_TKSTAT )
                    778: Return information about the number of characters sent and received
                    779: on ttys.
                    780: The third level names for the tty statistic variables are detailed below.
                    781: The changeable column shows whether a process
                    782: with appropriate privilege may change the value.
                    783: .Bl -column "KERNXTKSTATXRAWCCXXX" "struct integerXXX" -offset indent
                    784: .It Sy Third level name        Type    Changeable
                    785: .It kern.tkstat.cancc  quad    no
                    786: .It kern.tkstat.nin    quad    no
                    787: .It kern.tkstat.nout   quad    no
                    788: .It kern.tkstat.rawcc  quad    no
                    789: .El
                    790: .Pp
                    791: The variables are as follows:
                    792: .Bl -tag -width "123456"
                    793: .It Li kern.tkstat.cancc ( KERN_TKSTAT_CANCC )
                    794: The number of canonical input characters.
                    795: .It Li kern.tkstat.nin ( KERN_TKSTAT_NIN )
                    796: The total number of input characters.
                    797: .It Li kern.tkstat.nout ( KERN_TKSTAT_NOUT )
                    798: The total number of output characters.
                    799: .It Li kern.tkstat.rawcc ( KERN_TKSTAT_RAWCC )
                    800: The number of raw input characters.
                    801: .El
                    802: .It Li kern.urandom ( KERN_URND )
                    803: Random integer value.
                    804: .It Li kern.veriexec
                    805: Tunings for Verixec.
                    806: .Bl -tag -width "123456"
                    807: .It Li kern.veriexec.algorithms
                    808: Returns a string with the supported algorithms in Veriexec.
                    809: .It Li kern.veriexec.count
                    810: Sub-nodes are added to this node as new mounts are monitored by Veriexec.
                    811: Each mount will be under its own
                    812: .No tableN
                    813: node.
                    814: Under each node there will be three variables, indicating the mount
                    815: point, the file-system type, and the number of entries.
                    816: .It Li kern.veriexec.strict
                    817: Controls the strict level of Veriexec.
                    818: See
                    819: .Xr security 8
                    820: for more information on each level's implications.
                    821: .It Li kern.veriexec.verbose
                    822: Controls the verbosity level of Veriexec.
                    823: If 0, only the minimal
                    824: indication required will be given about what's happening - fingerprint
                    825: mismatches, removal of entries from the tables, modification of a
                    826: fingerprinted file.
                    827: If 1, more messages will be printed (ie., when a file with a valid
                    828: fingerprint is accessed).
                    829: Verbose level 2 is debug mode.
                    830: .El
                    831: .It Li kern.version ( KERN_VERSION )
                    832: The system version string.
                    833: .It Li kern.vnode ( KERN_VNODE )
                    834: Return the entire vnode table.
                    835: Note, the vnode table is not necessarily a consistent snapshot of
                    836: the system.
                    837: The returned data consists of an array whose size depends on the
                    838: current number of such objects in the system.
                    839: Each element of the array contains the kernel address of a vnode
                    840: .Va struct vnode *
                    841: followed by the vnode itself
                    842: .Va struct vnode .
                    843: .It Li kern.coredump.setid
                    844: Settings related to set-id processes coredumps.
                    845: By default, set-id processes do not dump core in situations where
                    846: other processes would.
                    847: The settings in this node allows an administrator to change this
                    848: behavior.
                    849: .Pp
                    850: .Bl -tag -width "123456"
                    851: .It Li kern.coredump.setid.dump
                    852: If non-zero, set-id processes will dump core.
                    853: .It Li kern.coredump.setid.group
                    854: The group-id for the set-id processes' coredump.
                    855: .It Li kern.coredump.setid.mode
                    856: The mode for the set-id processes' coredump.
                    857: See
                    858: .Xr chmod 1 .
                    859: .It Li kern.coredump.setid.owner
                    860: The user-id that will be used as the owner of the set-id processes'
                    861: coredump.
                    862: .It Li kern.coredump.setid.path
                    863: The path to which set-id processes' coredumps will be saved to.
                    864: Same syntax as kern.defcorename.
                    865: .El
                    866: .\" XXX kern.lwp
                    867: .El
                    868: .Sh The machdep.* subtree
                    869: The set of variables defined is architecture dependent.
                    870: Most architectures define at least the following variables.
                    871: .Bl -column "CONSOLE_DEVICEXXX" "integerXXX" -offset indent
                    872: .It Sy Second level name       Type    Changeable
                    873: .It Li CPU_CONSDEV     dev_t   no
                    874: .El
                    875: .Sh The net.* subtree
                    876: The string and integer information available for the
                    877: .Li net
                    878: level is detailed below.
                    879: The changeable column shows whether a process with appropriate
                    880: privilege may change the value.
                    881: The second and third levels are typically the protocol family and
                    882: protocol number, though this is not always the case.
                    883: .Bl -column "Second level nameX" "IPsec key management valuesX" -offset indent
                    884: .It Sy Second level name       Type    Changeable
                    885: .It net.route  routing messages        no
                    886: .It net.inet   IPv4 values     yes
                    887: .It net.inet6  IPv6 values     yes
                    888: .It net.key    IPsec key management values     yes
                    889: .El
                    890: .Pp
                    891: .Bl -tag -width "123456"
                    892: .It Li net.route ( PF_ROUTE )
                    893: .\" XXX really?
                    894: Return the entire routing table or a subset of it.
                    895: The data is returned as a sequence of routing messages (see
                    896: .Xr route 4
                    897: for the header file, format and meaning).
                    898: The length of each message is contained in the message header.
                    899: .Pp
                    900: The third level name is a protocol number, which is currently always 0.
                    901: The fourth level name is an address family, which may be set to 0 to
                    902: select all address families.
                    903: The fifth and sixth level names are as follows:
                    904: .Bl -column "Fifth level nameXXXXXX" "Sixth level is:XXX" -offset indent
                    905: .It Sy Fifth level name        Sixth level is:
                    906: .It NET\_RT\_FLAGS     rtflags
                    907: .It NET\_RT\_DUMP      None
                    908: .It NET\_RT\_IFLIST    None
                    909: .El
                    910: .It Li net.inet ( PF_INET )
                    911: Get or set various global information about the IPv4
                    912: .Pq Internet Protocol version 4 .
                    913: The third level name is the protocol.
                    914: The fourth level name is the variable name.
                    915: The currently defined protocols and names are:
                    916: .Bl -column "Protocol name" "sack.globalmaxholes" "integer" -offset 4n
                    917: .It Sy Protocol name   Variable name   Type    Changeable
                    918: .It arp        down    integer yes
                    919: .It arp        keep    integer yes
                    920: .It arp        prune   integer yes
                    921: .It arp        refresh integer yes
                    922: .It carp       allow   integer yes
                    923: .It carp       preempt integer yes
                    924: .It carp       log     integer yes
                    925: .It carp       arpbalance      integer yes
                    926: .It icmp       errppslimit     integer yes
                    927: .It icmp       maskrepl        integer yes
                    928: .It icmp       rediraccept     integer yes
                    929: .It icmp       redirtimeout    integer yes
                    930: .It ip allowsrcrt      integer yes
                    931: .It ip anonportmax     integer yes
                    932: .It ip anonportmin     integer yes
                    933: .It ip checkinterface  integer yes
                    934: .It ip directed-broadcast      integer yes
                    935: .It ip do_loopback_cksum       integer yes
                    936: .It ip forwarding      integer yes
                    937: .It ip forwsrcrt       integer yes
                    938: .It ip gifttl  integer yes
                    939: .It ip grettl  integer yes
                    940: .It ip hostzerobroadcast       integer yes
                    941: .It ip lowportmin      integer yes
                    942: .It ip lowportmax      integer yes
                    943: .It ip maxflows        integer yes
                    944: .It ip maxfragpackets  integer yes
                    945: .It ip mtudisc integer yes
                    946: .It ip mtudisctimeout  integer yes
                    947: .It ip random_id       integer yes
                    948: .It ip redirect        integer yes
                    949: .It ip subnetsarelocal integer yes
                    950: .It ip ttl     integer yes
                    951: .It tcp        rfc1323 integer yes
                    952: .It tcp        sendspace       integer yes
                    953: .It tcp        recvspace       integer yes
                    954: .It tcp        mssdflt integer yes
                    955: .It tcp        syn_cache_limit integer yes
                    956: .It tcp        syn_bucket_limit        integer yes
                    957: .It tcp        syn_cache_interval      integer yes
                    958: .It tcp        init_win        integer yes
                    959: .It tcp        init_win_local  integer yes
                    960: .It tcp        mss_ifmtu       integer yes
                    961: .It tcp        win_scale       integer yes
                    962: .It tcp        timestamps      integer yes
                    963: .It tcp        compat_42       integer yes
                    964: .It tcp        cwm     integer yes
                    965: .It tcp        cwm_burstsize   integer yes
                    966: .It tcp        ack_on_push     integer yes
                    967: .It tcp        keepidle        integer yes
                    968: .It tcp        keepintvl       integer yes
                    969: .It tcp        keepcnt integer yes
                    970: .It tcp        slowhz  integer no
                    971: .It tcp        log_refused     integer yes
                    972: .It tcp        rstppslimit     integer yes
                    973: .It tcp        ident   struct  no
                    974: .It tcp        sack.enable     integer yes
                    975: .It tcp        sack.globalholes        integer no
                    976: .It tcp        sack.globalmaxholes     integer yes
                    977: .It tcp        sack.maxholes   integer yes
                    978: .It tcp        ecn.enable      integer yes
                    979: .It tcp        ecn.maxretries  integer yes
                    980: .It tcp        congctl.selected        string  yes
                    981: .It tcp        congctl.available       string  yes
                    982: .It tcp        abc.enable      integer yes
                    983: .It tcp        abc.aggressive  integer yes
                    984: .It udp        checksum        integer yes
                    985: .It udp        do_loopback_cksum       integer yes
                    986: .It udp        recvspace       integer yes
                    987: .It udp        sendspace       integer yes
                    988: .El
                    989: .Pp
                    990: The variables are as follows:
                    991: .Bl -tag -width "123456"
                    992: .It Li arp.down
                    993: Failed ARP entry lifetime.
                    994: .It Li arp.keep
                    995: Valid ARP entry lifetime.
                    996: .It Li arp.prune
                    997: ARP cache pruning interval.
                    998: .It Li arp.refresh
                    999: ARP entry refresh interval.
                   1000: .It Li carp.allow
                   1001: If set to 0, incoming
                   1002: .Xr carp 4
                   1003: packets will not be processed.
                   1004: If set to any other value, processing will occur.
                   1005: Enabled by default.
                   1006: .It Li carp.arpbalance
                   1007: If set to any value other than 0, the ARP balancing functionality of
                   1008: .Xr carp 4
                   1009: is enabled.
                   1010: When ARP requests are received for an IP address which is part of any virtual
                   1011: host, carp will hash the source IP in the ARP request to select one of the
                   1012: virtual hosts from the set of all the virtual hosts which have that IP address.
                   1013: The master of that host will respond with the correct virtual MAC address.
                   1014: Disabled by default.
                   1015: .It Li carp.log
                   1016: If set to any value other than 0,
                   1017: .Xr carp 4
                   1018: will log errors.
                   1019: Disabled by default.
                   1020: .It Li carp.preempt
                   1021: If set to 0,
                   1022: .Xr carp 4
                   1023: will not attempt to become master if it is receiving advertisements from
                   1024: another active master.
                   1025: If set to any other value, carp will become master of the virtual host if it
                   1026: believes it can send advertisements more frequently than the current master.
                   1027: Disabled by default.
                   1028: .It Li ip.allowsrcrt
                   1029: If set to 1, the host accepts source routed packets.
                   1030: .It Li ip.anonportmax
                   1031: The highest port number to use for TCP and UDP ephemeral port allocation.
                   1032: This cannot be set to less than 1024 or greater than 65535, and must
                   1033: be greater than
                   1034: .Li ip.anonportmin .
                   1035: .It Li ip.anonportmin
                   1036: The lowest port number to use for TCP and UDP ephemeral port allocation.
                   1037: This cannot be set to less than 1024 or greater than 65535.
                   1038: .It Li ip.checkinterface
                   1039: If set to non-zero, the host will reject packets addressed to it
                   1040: that arrive on an interface not bound to that address.
                   1041: Currently, this must be disabled if ipnat is used to translate the
                   1042: destination address to another local interface, or if addresses
                   1043: are added to the loopback interface instead of the interface where
                   1044: the packets for those packets are received.
                   1045: .It Li ip.directed-broadcast
                   1046: If set to 1, enables directed broadcast behavior for the host.
                   1047: .It Li ip.do_loopback_cksum
                   1048: Perform IP checksum on loopback.
                   1049: .It Li ip.forwarding
                   1050: If set to 1, enables IP forwarding for the host,
                   1051: meaning that the host is acting as a router.
                   1052: .It Li ip.forwsrcrt
                   1053: If set to 1, enables forwarding of source-routed packets for the host.
                   1054: This value may only be changed if the kernel security level is less than 1.
                   1055: .It Li ip.gifttl
                   1056: The maximum time-to-live (hop count) value for an IPv4 packet generated by
                   1057: .Xr gif 4
                   1058: tunnel interface.
                   1059: .It Li ip.grettl
                   1060: The maximum time-to-live (hop count) value for an IPv4 packet generated by
                   1061: .Xr gre 4
                   1062: tunnel interface.
                   1063: .It Li ip.hostzerobroadcast
                   1064: All zeroes address is broadcast address.
                   1065: .It Li ip.lowportmax
                   1066: The highest port number to use for TCP and UDP reserved port allocation.
                   1067: This cannot be set to less than 0 or greater than 1024, and must
                   1068: be greater than
                   1069: .Li ip.lowportmin .
                   1070: .It Li ip.lowportmin
                   1071: The lowest port number to use for TCP and UDP reserved port allocation.
                   1072: This cannot be set to less than 0 or greater than 1024, and must
                   1073: be smaller than
                   1074: .Li ip.lowportmax .
                   1075: .It Li ip.maxflows
1.5       liamjfoy 1076: IPv4 Fast Forwarding is enabled by default.
                   1077: If set to 0, IPv4 Fast Forwarding is disabled.
1.1       pavel    1078: .Li ip.maxflows
                   1079: controls the maximum amount of flows which can be created.
                   1080: The default value is 256.
                   1081: .It Li ip.maxfragpackets
                   1082: The maximum number of fragmented packets the node will accept.
                   1083: 0 means that the node will not accept any fragmented packets.
                   1084: \-1 means that the node will accept as many fragmented packets as it receives.
                   1085: The flag is provided basically for avoiding possible DoS attacks.
                   1086: .It Li ip.mtudisc
                   1087: If set to 1, enables Path MTU Discovery (RFC 1191).
                   1088: When Path MTU Discovery is enabled, the transmitted TCP segment
                   1089: size will be determined by the advertised maximum segment size
                   1090: (MSS) from the remote end, as constrained by the path MTU.
                   1091: If MTU Discovery is disabled, the transmitted segment size will
                   1092: never be greater than
                   1093: .Li tcp.mssdflt
                   1094: (the local maximum segment size).
                   1095: .It Li ip.mtudisctimeout
                   1096: The number of seconds in which a route added by the Path MTU
                   1097: Discovery engine will time out.
                   1098: When the route times out, the Path
                   1099: MTU Discovery engine will attempt to probe a larger path MTU.
                   1100: .It Li ip.random_id
                   1101: Assign random ip_id values.
                   1102: .It Li ip.redirect
                   1103: If set to 1, ICMP redirects may be sent by the host.
                   1104: This option is ignored unless the host is routing IP packets,
                   1105: and should normally be enabled on all systems.
                   1106: .It Li ip.subnetsarelocal
                   1107: If set to 1, subnets are to be considered local addresses.
                   1108: .It Li ip.ttl
                   1109: The maximum time-to-live (hop count) value for an IP packet sourced by
                   1110: the system.
                   1111: This value applies to normal transport protocols, not to ICMP.
                   1112: .It Li icmp.errppslimit
                   1113: The variable specifies the maximum number of outgoing ICMP error messages,
                   1114: per second.
                   1115: ICMP error messages that exceeded the value are subject to rate limitation
                   1116: and will not go out from the node.
                   1117: Negative value disables rate limitation.
                   1118: .It Li icmp.maskrepl
                   1119: If set to 1, ICMP network mask requests are to be answered.
                   1120: .It Li icmp.rediraccept
                   1121: If set to non-zero, the host will accept ICMP redirect packets.
                   1122: Note that routers will never accept ICMP redirect packets,
                   1123: and the variable is meaningful on IP hosts only.
                   1124: .It Li icmp.redirtimeout
                   1125: The variable specifies lifetime of routing entries generated by incoming
                   1126: ICMP redirect.
                   1127: This defaults to 600 seconds.
                   1128: .It Li icmp.returndatabytes
                   1129: Number of bytes to return in an ICMP error message.
                   1130: .It Li tcp.ack_on_push
                   1131: If set to 1, TCP is to immediately transmit an ACK upon reception of
                   1132: a packet with PUSH set.
                   1133: This can avoid losing a round trip time in some rare situations,
                   1134: but has the caveat of potentially defeating TCP's delayed ACK algorithm.
                   1135: Use of this option is generally not recommended, but
                   1136: the variable exists in case your configuration really needs it.
                   1137: .It Li tcp.compat_42
                   1138: If set to 1, enables work-arounds for bugs in the 4.2BSD TCP implementation.
                   1139: Use of this option is not recommended, although it may be
                   1140: required in order to communicate with extremely old TCP implementations.
                   1141: .It Li tcp.cwm
                   1142: If set to 1, enables use of the Hughes/Touch/Heidemann Congestion Window
                   1143: Monitoring algorithm.
                   1144: This algorithm prevents line-rate bursts of packets that could
                   1145: otherwise occur when data begins flowing on an idle TCP connection.
                   1146: These line-rate bursts can contribute to network and router congestion.
                   1147: This can be particularly useful on World Wide Web servers
                   1148: which support HTTP/1.1, which has lingering connections.
                   1149: .It Li tcp.cwm_burstsize
                   1150: The Congestion Window Monitoring allowed burst size, in terms
                   1151: of packet count.
                   1152: .It Li tcp.delack_ticks
                   1153: Number of ticks to delay sending an ACK.
                   1154: .It Li tcp.do_loopback_cksum
                   1155: Perform TCP checksum on loopback.
                   1156: .It Li tcp.init_win
                   1157: A value indicating the TCP initial congestion window.
                   1158: If this value is 0, an auto-tuning algorithm designed to use an initial
                   1159: window of approximately 4K bytes is in use.
                   1160: Otherwise, this value indicates a fixed number of packets.
                   1161: .It Li tcp.init_win_local
                   1162: Like
                   1163: .Li tcp.init_win ,
                   1164: but used when communicating with hosts on a local network.
                   1165: .It Li tcp.keepcnt
                   1166: Number of keepalive probes sent before declaring a connection dead.
                   1167: If set to zero, there is no limit;
                   1168: keepalives will be sent until some kind of
                   1169: response is received from the peer.
                   1170: .It Li tcp.keepidle
                   1171: Time a connection must be idle before keepalives are sent (if keepalives
                   1172: are enabled for the connection).
                   1173: See also tcp.slowhz.
                   1174: .It Li tcp.keepintvl
                   1175: Time after a keepalive probe is sent until, in the absence of any response,
                   1176: another probe is sent.
                   1177: See also tcp.slowhz.
                   1178: .It Li tcp.log_refused
                   1179: If set to 1, refused TCP connections to the host will be logged.
                   1180: .It Li tcp.mss_ifmtu
                   1181: If set to 1, TCP calculates the outgoing maximum segment size based on
                   1182: the MTU of the appropriate interface.
                   1183: If set to 0, it is calculated based on the greater of the MTU of the
                   1184: interface, and the largest (non-loopback) interface MTU on the system.
                   1185: .It Li tcp.mssdflt
                   1186: The default maximum segment size both advertised to the peer
                   1187: and to use when either the peer does not advertise a maximum segment size to
                   1188: us during connection setup or Path MTU Discovery
                   1189: .Li ( ip.mtudisc )
                   1190: is disabled.
                   1191: Do not change this value unless you really know what you are doing.
                   1192: .It Li tcp.newreno
                   1193: If set to 1, enables the use of J.
                   1194: Hoe's NewReno congestion control algorithm.
                   1195: This algorithm improves the start-up behavior of TCP connections.
                   1196: .It Li tcp.recvspace
                   1197: The default TCP receive buffer size.
                   1198: .It Li tcp.rfc1323
                   1199: If set to 1, enables RFC 1323 extensions to TCP.
                   1200: .It Li tcp.rstppslimit
                   1201: The variable specifies the maximum number of outgoing TCP RST packets,
                   1202: per second.
                   1203: TCP RST packet that exceeded the value are subject to rate limitation
                   1204: and will not go out from the node.
                   1205: Negative value disables rate limitation.
                   1206: .It Li tcp.sack.enable
                   1207: If set to 1, enables RFC 2018 Selective ACKnowledgement.
                   1208: .It Li tcp.sack.globalholes
                   1209: Global number of TCP SACK holes.
                   1210: .It Li tcp.sack.globalmaxholes
                   1211: Global maximum number of TCP SACK holes.
                   1212: .It Li tcp.sack.maxholes
                   1213: Maximum number of TCP SACK holes allowed per connection.
                   1214: .It Li tcp.ecn.enable
                   1215: If set to 1, enables RFC 3168 Explicit Congestion Notification.
                   1216: .It Li tcp.ecn.maxretries
                   1217: Number of times to retry sending the ECN-setup packet.
                   1218: .It Li tcp.sendspace
                   1219: The default TCP send buffer size.
                   1220: .It Li tcp.slowhz
                   1221: The units for tcp.keepidle and tcp.keepintvl; those variables are in ticks
                   1222: of a clock that ticks tcp.slowhz times per second.
                   1223: (That is, their values
                   1224: must be divided by the tcp.slowhz value to get times in seconds.)
                   1225: .It Li tcp.syn_bucket_limit
                   1226: The maximum number of entries allowed per hash bucket in the TCP
                   1227: compressed state engine.
                   1228: .It Li tcp.syn_cache_limit
                   1229: The maximum number of entries allowed in the TCP compressed state
                   1230: engine.
                   1231: .It Li tcp.timestamps
                   1232: If rfc1323 is enabled, a value of 1 indicates RFC 1323 time stamp options,
                   1233: used for measuring TCP round trip times, are enabled.
                   1234: .It Li tcp.win_scale
                   1235: If rfc1323 is enabled, a value of 1 indicates RFC 1323 window scale options,
                   1236: for increasing the TCP window size, are enabled.
                   1237: .It Li tcp.congctl.available
                   1238: The available TCP congestion control algorithms.
                   1239: .It Li tcp.congctl.selected
                   1240: The currently selected TCP congestion control algorithm.
                   1241: .It Li tcp.abc.enable
                   1242: If set to 1, use RFC 3465 Appropriate Byte Counting (ABC).
                   1243: If set to 0, use traditional Packet Counting.
                   1244: .It Li tcp.abc.aggressive
                   1245: Choose the L parameter found in RFC 3465.
                   1246: L is the maximum cwnd increase for an ack during slow start.
                   1247: If set to 1, use L=2*SMSS.
                   1248: If set to 0, use L=1*SMSS.
                   1249: It has no effect unless tcp.abc.enable is set to 1.
                   1250: .It Li udp.checksum
                   1251: If set to 1, UDP checksums are being computed.
                   1252: Received non-zero UDP checksums are always checked.
                   1253: Disabling UDP checksums is strongly discouraged.
                   1254: .It Li udp.sendspace
                   1255: The default UDP send buffer size.
                   1256: .It Li udp.recvspace
                   1257: The default UDP receive buffer size.
                   1258: .El
                   1259: .Pp
                   1260: For variables net.*.ipsec, please refer to
                   1261: .Xr ipsec 4 .
                   1262: .It Li net.inet6 ( PF_INET6 )
                   1263: Get or set various global information about the IPv6
                   1264: .Pq Internet Protocol version 6 .
                   1265: The third level name is the protocol.
                   1266: The fourth level name is the variable name.
                   1267: The currently defined protocols and names are:
                   1268: .Bl -column "Protocol name" "Variable nameXX" "integer" "yes" -offset indent
                   1269: .It Sy Protocol name   Variable name   Type    Changeable
                   1270: .It icmp6      errppslimit     integer yes
                   1271: .It icmp6      mtudisc_hiwat   integer yes
                   1272: .It icmp6      mtudisc_lowat   integer yes
                   1273: .It icmp6      nd6_debug       integer yes
                   1274: .It icmp6      nd6_delay       integer yes
                   1275: .It icmp6      nd6_maxnudhint  integer yes
                   1276: .It icmp6      nd6_mmaxtries   integer yes
                   1277: .It icmp6      nd6_prune       integer yes
                   1278: .It icmp6      nd6_umaxtries   integer yes
                   1279: .It icmp6      nd6_useloopback integer yes
                   1280: .It icmp6      nodeinfo        integer yes
                   1281: .It icmp6      rediraccept     integer yes
                   1282: .It icmp6      redirtimeout    integer yes
                   1283: .It ip6        accept_rtadv    integer yes
                   1284: .It ip6        anonportmax     integer yes
                   1285: .It ip6        anonportmin     integer yes
                   1286: .It ip6        auto_flowlabel  integer yes
                   1287: .It ip6        dad_count       integer yes
                   1288: .It ip6        defmcasthlim    integer yes
                   1289: .It ip6        forwarding      integer yes
                   1290: .It ip6        gifhlim integer yes
                   1291: .It ip6        hlim    integer yes
                   1292: .It ip6        hdrnestlimit    integer yes
                   1293: .It ip6        kame_version    string  no
                   1294: .It ip6        keepfaith       integer yes
                   1295: .It ip6        log_interval    integer yes
                   1296: .It ip6        lowportmax      integer yes
                   1297: .It ip6        lowportmin      integer yes
1.5       liamjfoy 1298: .It ip6        maxflows        integer yes
1.1       pavel    1299: .It ip6        maxfragpackets  integer yes
                   1300: .It ip6        maxfrags        integer yes
                   1301: .It ip6        redirect        integer yes
                   1302: .It ip6        rr_prune        integer yes
                   1303: .It ip6        use_deprecated  integer yes
                   1304: .It ip6        v6only  integer yes
                   1305: .It udp6       do_loopback_cksum       integer yes
                   1306: .It udp6       recvspace       integer yes
                   1307: .It udp6       sendspace       integer yes
                   1308: .El
                   1309: .Pp
                   1310: The variables are as follows:
                   1311: .Bl -tag -width "123456"
                   1312: .It Li ip6.accept_rtadv
                   1313: If set to non-zero, the node will accept ICMPv6 router advertisement packets
                   1314: and autoconfigures address prefixes and default routers.
                   1315: The node must be a host
                   1316: .Pq not a router
                   1317: for the option to be meaningful.
                   1318: .It Li ip6.anonportmax
                   1319: The highest port number to use for TCP and UDP ephemeral port allocation.
                   1320: This cannot be set to less than 1024 or greater than 65535, and must
                   1321: be greater than
                   1322: .Li ip6.anonportmin .
                   1323: .It Li ip6.anonportmin
                   1324: The lowest port number to use for TCP and UDP ephemeral port allocation.
                   1325: This cannot be set to less than 1024 or greater than 65535.
                   1326: .It Li ip6.auto_flowlabel
                   1327: On connected transport protocol packets,
                   1328: fill IPv6 flowlabel field to help intermediate routers to identify packet flows.
                   1329: .It Li ip6.dad_count
                   1330: The variable configures number of IPv6 DAD
                   1331: .Pq duplicated address detection
                   1332: probe packets.
                   1333: The packets will be generated when IPv6 interface addresses are configured.
                   1334: .It Li ip6.defmcasthlim
                   1335: The default hop limit value for an IPv6 multicast packet sourced by the node.
                   1336: This value applies to all the transport protocols on top of IPv6.
                   1337: There are APIs to override the value, as documented in
                   1338: .Xr ip6 4 .
                   1339: .It Li ip6.forwarding
                   1340: If set to 1, enables IPv6 forwarding for the node,
                   1341: meaning that the node is acting as a router.
                   1342: If set to 0, disables IPv6 forwarding for the node,
                   1343: meaning that the node is acting as a host.
                   1344: IPv6 specification defines node behavior for
                   1345: .Dq router
                   1346: case and
                   1347: .Dq host
                   1348: case quite differently, and changing this variable during operation
                   1349: may cause serious trouble.
                   1350: It is recommended to configure the variable at bootstrap time,
                   1351: and bootstrap time only.
                   1352: .It Li ip6.gifhlim
                   1353: The maximum hop limit value for an IPv6 packet generated by
                   1354: .Xr gif 4
                   1355: tunnel interface.
                   1356: .It Li ip6.hdrnestlimit
                   1357: The number of IPv6 extension headers permitted on incoming IPv6 packets.
                   1358: If set to 0, the node will accept as many extension headers as possible.
                   1359: .It Li ip6.hlim
                   1360: The default hop limit value for an IPv6 unicast packet sourced by the node.
                   1361: This value applies to all the transport protocols on top of IPv6.
                   1362: There are APIs to override the value, as documented in
                   1363: .Xr ip6 4 .
                   1364: .It Li ip6.kame_version
                   1365: The string identifies the version of KAME IPv6 stack implemented in the kernel.
                   1366: .It Li ip6.keepfaith
                   1367: If set to non-zero, it enables
                   1368: .Dq FAITH
                   1369: TCP relay IPv6-to-IPv4 translator code in the kernel.
                   1370: Refer
                   1371: .Xr faith 4
                   1372: and
                   1373: .Xr faithd 8
                   1374: for detail.
                   1375: .It Li ip6.log_interval
                   1376: The variable controls amount of logs generated by IPv6 packet
                   1377: forwarding engine, by setting interval between log output
                   1378: .Pq in seconds .
                   1379: .It Li ip6.lowportmax
                   1380: The highest port number to use for TCP and UDP reserved port allocation.
                   1381: This cannot be set to less than 0 or greater than 1024, and must
                   1382: be greater than
                   1383: .Li ip6.lowportmin .
                   1384: .It Li ip6.lowportmin
                   1385: The lowest port number to use for TCP and UDP reserved port allocation.
                   1386: This cannot be set to less than 0 or greater than 1024, and must
                   1387: be smaller than
                   1388: .Li ip6.lowportmax .
1.5       liamjfoy 1389: .It Li ip6.maxflows
                   1390: IPv6 Fast Forwarding is enabled by default.
                   1391: If set to 0, IPv6 Fast Forwarding is disabled.
                   1392: .Li ip6.maxflows
                   1393: controls the maximum amount of flows which can be created.
1.6     ! liamjfoy 1394: The default value is 256.
1.1       pavel    1395: .It Li ip6.maxfragpackets
                   1396: The maximum number of fragmented packets the node will accept.
                   1397: 0 means that the node will not accept any fragmented packets.
                   1398: \-1 means that the node will accept as many fragmented packets as it receives.
                   1399: The flag is provided basically for avoiding possible DoS attacks.
                   1400: .It Li ip6.maxfrags
                   1401: The maximum number of fragments the node will accept.
                   1402: 0 means that the node will not accept any fragments.
                   1403: \-1 means that the node will accept as many fragments as it receives.
                   1404: The flag is provided basically for avoiding possible DoS attacks.
                   1405: .It Li ip6.redirect
                   1406: If set to 1, ICMPv6 redirects may be sent by the node.
                   1407: This option is ignored unless the node is routing IP packets,
                   1408: and should normally be enabled on all systems.
                   1409: .It Li ip6.rr_prune
                   1410: The variable specifies interval between IPv6 router renumbering prefix
                   1411: babysitting, in seconds.
                   1412: .It Li ip6.use_deprecated
                   1413: The variable controls use of deprecated address, specified in RFC 2462 5.5.4.
                   1414: .It Li ip6.v6only
                   1415: The variable specifies initial value for
                   1416: .Dv IPV6_V6ONLY
                   1417: socket option for
                   1418: .Dv AF_INET6
                   1419: socket.
                   1420: Please refer to
                   1421: .Xr ip6 4
                   1422: for detail.
                   1423: .It Li icmp6.errppslimit
                   1424: The variable specifies the maximum number of outgoing ICMPv6 error messages,
                   1425: per second.
                   1426: ICMPv6 error messages that exceeded the value are subject to rate limitation
                   1427: and will not go out from the node.
                   1428: Negative value disables rate limitation.
                   1429: .It Li icmp6.mtudisc_hiwat
                   1430: .It Li icmp6.mtudisc_lowat
                   1431: The variables define the maximum number of routing table entries,
                   1432: created due to path MTU discovery
                   1433: .Pq prevents denial-of-service attacks with ICMPv6 too big messages .
                   1434: When IPv6 path MTU discovery happens, we keep path MTU information into
                   1435: the routing table.
                   1436: If the number of routing table entries exceed the value,
                   1437: the kernel will not attempt to keep the path MTU information.
                   1438: .Li icmp6.mtudisc_hiwat
                   1439: is used when we have verified ICMPv6 too big messages.
                   1440: .Li icmp6.mtudisc_lowat
                   1441: is used when we have unverified ICMPv6 too big messages.
                   1442: Verification is performed by using address/port pairs kept in connected pcbs.
                   1443: Negative value disables the upper limit.
                   1444: .It Li icmp6.nd6_debug
                   1445: If set to non-zero, kernel IPv6 neighbor discovery code will generate
                   1446: debugging messages.
                   1447: The debug outputs are useful to diagnose IPv6 interoperability issues.
                   1448: The flag must be set to 0 for normal operation.
                   1449: .It Li icmp6.nd6_delay
                   1450: The variable specifies
                   1451: .Dv DELAY_FIRST_PROBE_TIME
                   1452: timing constant in IPv6 neighbor discovery specification
                   1453: .Pq RFC 2461 ,
                   1454: in seconds.
                   1455: .It Li icmp6.nd6_maxnudhint
                   1456: IPv6 neighbor discovery permits upper layer protocols to supply reachability
                   1457: hints, to avoid unnecessary neighbor discovery exchanges.
                   1458: The variable defines the number of consecutive hints the neighbor discovery
                   1459: layer will take.
                   1460: For example, by setting the variable to 3, neighbor discovery layer
                   1461: will take 3 consecutive hints in maximum.
                   1462: After receiving 3 hints, neighbor discovery layer will perform
                   1463: normal neighbor discovery process.
                   1464: .It Li icmp6.nd6_mmaxtries
                   1465: The variable specifies
                   1466: .Dv MAX_MULTICAST_SOLICIT
                   1467: constant in IPv6 neighbor discovery specification
                   1468: .Pq RFC 2461 .
                   1469: .It Li icmp6.nd6_prune
                   1470: The variable specifies interval between IPv6 neighbor cache babysitting,
                   1471: in seconds.
                   1472: .It Li icmp6.nd6_umaxtries
                   1473: The variable specifies
                   1474: .Dv MAX_UNICAST_SOLICIT
                   1475: constant in IPv6 neighbor discovery specification
                   1476: .Pq RFC 2461 .
                   1477: .It Li icmp6.nd6_useloopback
                   1478: If set to non-zero, kernel IPv6 stack will use loopback interface for
                   1479: local traffic.
                   1480: .It Li icmp6.nodeinfo
                   1481: The variable enables responses to ICMPv6 node information queries.
                   1482: If you set the variable to 0, responses will not be generated for
                   1483: ICMPv6 node information queries.
                   1484: Since node information queries can have a security impact, it is
                   1485: possible to fine tune which responses should be answered.
                   1486: Two separate bits can be set.
                   1487: .Bl -tag -width "12345"
                   1488: .It 1
                   1489: Respond to ICMPv6 FQDN queries, e.g.
                   1490: .Li ping6 -w .
                   1491: .It 2
                   1492: Respond to ICMPv6 node addresses queries, e.g.
                   1493: .Li ping6 -a .
                   1494: .El
                   1495: .It Li icmp6.rediraccept
                   1496: If set to non-zero, the host will accept ICMPv6 redirect packets.
                   1497: Note that IPv6 routers will never accept ICMPv6 redirect packets,
                   1498: and the variable is meaningful on IPv6 hosts
                   1499: .Pq non-router
                   1500: only.
                   1501: .It Li icmp6.redirtimeout
                   1502: The variable specifies lifetime of routing entries generated by incoming
                   1503: ICMPv6 redirect.
                   1504: .It Li udp6.do_loopback_cksum
                   1505: Perform UDP checksum on loopback.
                   1506: .It Li udp6.recvspace
                   1507: Default UDP receive buffer size.
                   1508: .It Li udp6.sendspace
                   1509: Default UDP send buffer size.
                   1510: .El
                   1511: .Pp
                   1512: We reuse net.*.tcp for
                   1513: .Tn TCP
                   1514: over
                   1515: .Tn IPv6 ,
                   1516: and therefore we do not have variables net.*.tcp6.
                   1517: Variables net.inet6.udp6 have identical meaning to net.inet.udp.
                   1518: Please refer to
                   1519: .Li PF_INET
                   1520: section above.
                   1521: For variables net.*.ipsec6, please refer to
                   1522: .Xr ipsec 4 .
                   1523: .It Li net.key ( PF_KEY )
                   1524: Get or set various global information about the IPsec key management.
                   1525: The third level name is the variable name.
                   1526: The currently defined variable and names are:
                   1527: .Bl -column "blockacq_lifetime" "integer" "yes" -offset indent
                   1528: .It Sy Variable name   Type    Changeable
                   1529: .It debug      integer yes
                   1530: .It spi_try    integer yes
                   1531: .It spi_min_value      integer yes
                   1532: .It spi_max_value      integer yes
                   1533: .It larval_lifetime    integer yes
                   1534: .It blockacq_count     integer yes
                   1535: .It blockacq_lifetime  integer yes
                   1536: .It esp_keymin integer yes
                   1537: .It esp_auth   integer yes
                   1538: .It ah_keymin  integer yes
                   1539: .El
                   1540: The variables are as follows:
                   1541: .Bl -tag -width "123456"
                   1542: .It Li debug
                   1543: Turn on debugging message from within the kernel.
                   1544: The value is a bitmap, as defined in
                   1545: .Pa /usr/include/netkey/key_debug.h .
                   1546: .It Li spi_try
                   1547: The number of times the kernel will try to obtain an unique SPI
                   1548: when it generates it from random number generator.
                   1549: .It Li spi_min_value
                   1550: Minimum SPI value when generating it within the kernel.
                   1551: .It Li spi_max_value
                   1552: Maximum SPI value when generating it within the kernel.
                   1553: .It Li larval_lifetime
                   1554: Lifetime for LARVAL SAD entries, in seconds.
                   1555: .It Li blockacq_count
                   1556: Number of ACQUIRE PF_KEY messages to be blocked after an ACQUIRE message.
                   1557: It avoids flood of ACQUIRE PF_KEY from being sent from the kernel to the
                   1558: key management daemon.
                   1559: .It Li blockacq_lifetime
                   1560: Lifetime of ACQUIRE PF_KEY message.
                   1561: .It Li esp_keymin
                   1562: Minimum ESP key length, in bits.
                   1563: The value is used when the kernel creates proposal payload
                   1564: on ACQUIRE PF_KEY message.
                   1565: .It Li esp_auth
                   1566: Whether ESP authentication should be used or not.
                   1567: Non-zero value indicates that ESP authentication should be used.
                   1568: The value is used when the kernel creates proposal payload
                   1569: on ACQUIRE PF_KEY message.
                   1570: .It Li ah_keymin
                   1571: Minimum AH key length, in bits,
                   1572: The value is used when the kernel creates proposal payload
                   1573: on ACQUIRE PF_KEY message.
                   1574: .El
                   1575: .El
                   1576: .Sh The proc.* subtree
                   1577: The string and integer information available for the
                   1578: .Li proc
                   1579: level is detailed below.
                   1580: The changeable column shows whether a process with appropriate
                   1581: privilege may change the value.
                   1582: These values are per-process,
                   1583: and as such may change from one process to another.
                   1584: When a process is created,
                   1585: the default values are inherited from its parent.
                   1586: When a set-user-ID or set-group-ID binary is executed, the
                   1587: value of PROC_PID_CORENAME is reset to the system default value.
                   1588: The second level name is either the magic value PROC_CURPROC, which
                   1589: points to the current process, or the PID of the target process.
                   1590: .Bl -column "USER_COLL_WEIGHTS_MAXXXX" "integerXXX" "yes" -offset indent
                   1591: .It Sy Third level name        Type    Changeable
                   1592: .It proc.pid.corename  string  yes
                   1593: .It proc.pid.rlimit    node    not applicable
                   1594: .It proc.pid.stopfork  int     yes
                   1595: .It proc.pid.stopexec  int     yes
                   1596: .It proc.pid.stopexit  int     yes
                   1597: .El
                   1598: .Bl -tag -width "123456"
                   1599: .Pp
                   1600: .It Li proc.pid.corename ( PROC_PID_CORENAME )
                   1601: The template used for the core dump file name (see
                   1602: .Xr core 5
                   1603: for details).
                   1604: The base name must either be
                   1605: .Nm core
                   1606: or end with the suffix ``.core'' (the super-user may set arbitrary names).
                   1607: By default it points to KERN_DEFCORENAME.
                   1608: .It Li proc.pid.rlimit ( PROC_PID_LIMIT )
                   1609: Return resources limits, as defined for the
                   1610: .Xr getrlimit 2
                   1611: and
                   1612: .Xr setrlimit 2
                   1613: system calls.
                   1614: The fourth level name is one of:
                   1615: .Bl -tag -width PROC_PID_LIMIT_MEMLOCKAA
                   1616: .It Li proc.pid.rlimit.cputime ( PROC_PID_LIMIT_CPU )
                   1617: The maximum amount of CPU time (in seconds) to be used by each process.
                   1618: .It Li proc.pid.rlimit.filesize ( PROC_PID_LIMIT_FSIZE )
                   1619: The largest size (in bytes) file that may be created.
                   1620: .It Li proc.pid.rlimit.datasize ( PROC_PID_LIMIT_DATA )
                   1621: The maximum size (in bytes) of the data segment for a process;
                   1622: this defines how far a program may extend its break with the
                   1623: .Xr sbrk 2
                   1624: system call.
                   1625: .It Li proc.pid.rlimit.stacksize ( PROC_PID_LIMIT_STACK )
                   1626: The maximum size (in bytes) of the stack segment for a process;
                   1627: this defines how far a program's stack segment may be extended.
                   1628: Stack extension is performed automatically by the system.
                   1629: .It Li proc.pid.rlimit.coredumpsize ( PROC_PID_LIMIT_CORE )
                   1630: The largest size (in bytes)
                   1631: .Pa core
                   1632: file that may be created.
                   1633: .It Li proc.pid.rlimit.memoryuse ( PROC_PID_LIMIT_RSS )
                   1634: The maximum size (in bytes) to which a process's resident set size may
                   1635: grow.
                   1636: This imposes a limit on the amount of physical memory to be given to
                   1637: a process; if memory is tight, the system will prefer to take memory
                   1638: from processes that are exceeding their declared resident set size.
                   1639: .It Li proc.pid.rlimit.memorylocked ( PROC_PID_LIMIT_MEMLOCK )
                   1640: The maximum size (in bytes) which a process may lock into memory
                   1641: using the
                   1642: .Xr mlock 2
                   1643: function.
                   1644: .It Li proc.pid.rlimit.maxproc ( PROC_PID_LIMIT_NPROC )
                   1645: The maximum number of simultaneous processes for this user id.
                   1646: .It Li proc.pid.rlimit.descriptors ( PROC_PID_LIMIT_NOFILE )
                   1647: The maximum number of open files for this process.
                   1648: .\" XXX proc.pid.rlimit.sbsize
                   1649: .El
                   1650: .Pp
                   1651: The fifth level name is one of
                   1652: .Li soft ( PROC_PID_LIMIT_TYPE_SOFT ) or
                   1653: .Li hard ( PROC_PID_LIMIT_TYPE_HARD ) ,
                   1654: to select respectively the soft or hard limit.
                   1655: Both are of type integer.
                   1656: .It Li proc.pid.stopfork ( PROC_PID_STOPFORK )
                   1657: If non zero, the process' children will be stopped after
                   1658: .Xr fork 2
                   1659: calls.
                   1660: The children is created in the SSTOP state and is never scheduled
                   1661: for running before being stopped.
                   1662: This feature helps attaching a process with a debugger such as
                   1663: .Xr gdb 1
                   1664: before it had the opportunity to actually do anything.
                   1665: .Pp
                   1666: This value is inherited by the process's children, and it also
                   1667: apply to emulation specific system calls that fork a new process, such as
                   1668: .Fn sproc
                   1669: or
                   1670: .Fn clone .
                   1671: .It Li proc.pid.stopexec ( PROC_PID_STOPEXEC )
                   1672: If non zero, the process will be stopped on next
                   1673: .Xr exec 3
                   1674: call.
                   1675: The process created by
                   1676: .Xr exec 3
                   1677: is created in the SSTOP state and is never scheduled for running
                   1678: before being stopped.
                   1679: This feature helps attaching a process with a debugger such as
                   1680: .Xr gdb 1
                   1681: before it had the opportunity to actually do anything.
                   1682: .Pp
                   1683: This value is inherited by the process's children.
                   1684: .It Li proc.pid.stopexit ( PROC_PID_STOPEXIT )
                   1685: If non zero, the process will be stopped on when it has cause to exit,
                   1686: either by way of calling
                   1687: .Xr exit 3 ,
                   1688: .Xr _exit 2 ,
                   1689: or by the receipt of a specific signal.
                   1690: The process is stopped before any of its resources or vm space is
                   1691: released allowing examination of the termination state of a process
                   1692: before it disappears.
                   1693: This feature can be used to examine the final conditions of the
                   1694: process's vmspace via
                   1695: .Xr pmap 1
                   1696: or its resource settings with
                   1697: .Xr sysctl 8
                   1698: before it disappears.
                   1699: .Pp
                   1700: This value is also inherited by the process's children.
                   1701: .El
                   1702: .Sh The user.* subtree ( CTL_USER )
                   1703: The string and integer information available for the
                   1704: .Li user
                   1705: level is detailed below.
                   1706: The changeable column shows whether a process with appropriate
                   1707: privilege may change the value.
                   1708: .Bl -column "USER_COLL_WEIGHTS_MAXXXX" "integerXXX" -offset indent
                   1709: .It Sy Second level name       Type    Changeable
                   1710: .It user.atexit_max    integer no
                   1711: .It user.bc_base_max   integer no
                   1712: .It user.bc_dim_max    integer no
                   1713: .It user.bc_scale_max  integer no
                   1714: .It user.bc_string_max integer no
                   1715: .It user.coll_weights_max      integer no
                   1716: .It user.cs_path       string  no
                   1717: .It user.expr_nest_max integer no
                   1718: .It user.line_max      integer no
                   1719: .It user.posix2_c_bind integer no
                   1720: .It user.posix2_c_dev  integer no
                   1721: .It user.posix2_char_term      integer no
                   1722: .It user.posix2_fort_dev       integer no
                   1723: .It user.posix2_fort_run       integer no
                   1724: .It user.posix2_localedef      integer no
                   1725: .It user.posix2_sw_dev integer no
                   1726: .It user.posix2_upe    integer no
                   1727: .It user.posix2_version        integer no
                   1728: .It user.re_dup_max    integer no
                   1729: .It user.stream_max    integer no
                   1730: .It user.stream_max    integer no
                   1731: .It user.tzname_max    integer no
                   1732: .El
                   1733: .Bl -tag -width "123456"
                   1734: .Pp
                   1735: .It Li user.atexit_max ( USER_ATEXIT_MAX )
                   1736: The maximum number of functions that may be registered with
                   1737: .Xr atexit 3 .
                   1738: .It Li user.bc_base_max ( USER_BC_BASE_MAX )
                   1739: The maximum ibase/obase values in the
                   1740: .Xr bc 1
                   1741: utility.
                   1742: .It Li user.bc_dim_max ( USER_BC_DIM_MAX )
                   1743: The maximum array size in the
                   1744: .Xr bc 1
                   1745: utility.
                   1746: .It Li user.bc_scale_max ( USER_BC_SCALE_MAX )
                   1747: The maximum scale value in the
                   1748: .Xr bc 1
                   1749: utility.
                   1750: .It Li user.bc_string_max ( USER_BC_STRING_MAX )
                   1751: The maximum string length in the
                   1752: .Xr bc 1
                   1753: utility.
                   1754: .It Li user.coll_weights_max ( USER_COLL_WEIGHTS_MAX )
                   1755: The maximum number of weights that can be assigned to any entry of
                   1756: the LC_COLLATE order keyword in the locale definition file.
                   1757: .It Li user.cs_path ( USER_CS_PATH )
                   1758: Return a value for the
                   1759: .Ev PATH
                   1760: environment variable that finds all the standard utilities.
                   1761: .It Li user.expr_nest_max ( USER_EXPR_NEST_MAX )
                   1762: The maximum number of expressions that can be nested within
                   1763: parenthesis by the
                   1764: .Xr expr 1
                   1765: utility.
                   1766: .It Li user.line_max ( USER_LINE_MAX )
                   1767: The maximum length in bytes of a text-processing utility's input
                   1768: line.
                   1769: .It Li user.posix2_char_term ( USER_POSIX2_CHAR_TERM )
                   1770: Return 1 if the system supports at least one terminal type capable of
                   1771: all operations described in POSIX 1003.2, otherwise 0.
                   1772: .It Li user.posix2_c_bind ( USER_POSIX2_C_BIND )
                   1773: Return 1 if the system's C-language development facilities support the
                   1774: C-Language Bindings Option, otherwise 0.
                   1775: .It Li user.posix2_c_dev ( USER_POSIX2_C_DEV )
                   1776: Return 1 if the system supports the C-Language Development Utilities Option,
                   1777: otherwise 0.
                   1778: .It Li user.posix2_fort_dev ( USER_POSIX2_FORT_DEV )
                   1779: Return 1 if the system supports the FORTRAN Development Utilities Option,
                   1780: otherwise 0.
                   1781: .It Li user.posix2_fort_run ( USER_POSIX2_FORT_RUN )
                   1782: Return 1 if the system supports the FORTRAN Runtime Utilities Option,
                   1783: otherwise 0.
                   1784: .It Li user.posix2_localedef ( USER_POSIX2_LOCALEDEF )
                   1785: Return 1 if the system supports the creation of locales, otherwise 0.
                   1786: .It Li user.posix2_sw_dev ( USER_POSIX2_SW_DEV )
                   1787: Return 1 if the system supports the Software Development Utilities Option,
                   1788: otherwise 0.
                   1789: .It Li user.posix2_upe ( USER_POSIX2_UPE )
                   1790: Return 1 if the system supports the User Portability Utilities Option,
                   1791: otherwise 0.
                   1792: .It Li user.posix2_version ( USER_POSIX2_VERSION )
                   1793: The version of POSIX 1003.2 with which the system attempts to comply.
                   1794: .It Li user.re_dup_max ( USER_RE_DUP_MAX )
                   1795: The maximum number of repeated occurrences of a regular expression
                   1796: permitted when using interval notation.
                   1797: .ne 1i
                   1798: .It Li user.stream_max ( USER_STREAM_MAX )
                   1799: The minimum maximum number of streams that a process may have open
                   1800: at any one time.
                   1801: .It Li user.tzname_max ( USER_TZNAME_MAX )
                   1802: The minimum maximum number of types supported for the name of a
                   1803: timezone.
                   1804: .El
                   1805: .Sh The vm.* subtree ( CTL_VM )
                   1806: The string and integer information available for the
                   1807: .Li vm
                   1808: level is detailed below.
                   1809: The changeable column shows whether a process with appropriate
                   1810: privilege may change the value.
                   1811: .Bl -column "Second level nameXXXXXX" "struct uvmexp_sysctlXXX" -offset indent
                   1812: .It Sy Second level name       Type    Changeable
                   1813: .It vm.anonmax int     yes
                   1814: .It vm.anonmin int     yes
                   1815: .It vm.bufcache        int     yes
                   1816: .It vm.bufmem  int     no
                   1817: .It vm.bufmem_hiwater  int     yes
                   1818: .It vm.bufmem_lowater  int     yes
                   1819: .It vm.execmax int     yes
                   1820: .It vm.execmin int     yes
                   1821: .It vm.filemax int     yes
                   1822: .It vm.filemin int     yes
                   1823: .It vm.loadavg struct loadavg  no
                   1824: .It vm.maxslp  int     no
                   1825: .It vm.nkmempages      int     no
                   1826: .It vm.uspace  int     no
                   1827: .It vm.uvmexp  struct uvmexp   no
                   1828: .It vm.uvmexp2 struct uvmexp_sysctl    no
                   1829: .It vm.vmmeter struct vmtotal  no
                   1830: .El
                   1831: .Pp
                   1832: .Bl -tag -width "123456"
                   1833: .It Li vm.anonmax ( VM_ANONMAX )
                   1834: The percentage of physical memory which will be reclaimed
                   1835: from other types of memory usage to store anonymous application data.
                   1836: .It Li vm.anonmin ( VM_ANONMIN )
                   1837: The percentage of physical memory which will be always be available for
                   1838: anonymous application data.
                   1839: .It Li vm.bufcache ( VM_BUFCACHE )
                   1840: The percentage of physical memory which will be available
                   1841: for the buffer cache.
                   1842: .It Li vm.bufmem ( VM_BUFMEM )
                   1843: The amount of kernel memory that is being used by the buffer cache.
                   1844: .It Li vm.bufmem_lowater ( VM_BUFMEM_LOWATER )
                   1845: The minimum amount of kernel memory to reserve for the
                   1846: buffer cache.
                   1847: .It Li vm.bufmem_hiwater ( VM_BUFMEM_HIWATER )
                   1848: The maximum amount of kernel memory to be used for the
                   1849: buffer cache.
                   1850: .It Li vm.execmax ( VM_EXECMAX )
                   1851: The percentage of physical memory which will be reclaimed
                   1852: from other types of memory usage to store cached executable data.
                   1853: .It Li vm.execmin ( VM_EXECMIN )
                   1854: The percentage of physical memory which will be always be available for
                   1855: cached executable data.
                   1856: .It Li vm.filemax ( VM_FILEMAX )
                   1857: The percentage of physical memory which will be reclaimed
                   1858: from other types of memory usage to store cached file data.
                   1859: .It Li vm.filemin ( VM_FILEMIN )
                   1860: The percentage of physical memory which will be always be available for
                   1861: cached file data.
                   1862: .It Li vm.loadavg ( VM_LOADAVG )
                   1863: Return the load average history.
                   1864: The returned data consists of a
                   1865: .Va struct loadavg .
                   1866: .It Li vm.maxslp ( VM_MAXSLP )
                   1867: The value of the maxslp kernel global variable.
                   1868: .It Li vm.vmmeter ( VM_METER )
                   1869: Return system wide virtual memory statistics.
                   1870: The returned data consists of a
                   1871: .Va struct vmtotal .
                   1872: .It Li vm.uspace ( VM_USPACE )
                   1873: The number of bytes allocated for each kernel stack.
                   1874: .It Li vm.uvmexp ( VM_UVMEXP )
                   1875: Return system wide virtual memory statistics.
                   1876: The returned data consists of a
                   1877: .Va struct uvmexp .
                   1878: .It Li vm.uvmexp2 ( VM_UVMEXP2 )
                   1879: Return system wide virtual memory statistics.
                   1880: The returned data consists of a
                   1881: .Va struct uvmexp_sysctl .
                   1882: .\" XXX vm.idlezero
                   1883: .El
                   1884: .Sh The ddb.* subtree ( CTL_DDB )
                   1885: The integer information available for the
                   1886: .Li ddb
                   1887: level is detailed below.
                   1888: The changeable column shows whether a process with appropriate
                   1889: privilege may change the value.
                   1890: .\" XXX sort
                   1891: .Bl -column "ddb.fromconsoleXXX" "integerXXX" -offset indent
                   1892: .It Sy Second level name       Type    Changeable
                   1893: .It ddb.radix  integer yes
                   1894: .It ddb.maxoff integer yes
                   1895: .It ddb.lines  integer yes
                   1896: .It ddb.tabstops       integer yes
                   1897: .It ddb.onpanic        integer yes
                   1898: .It ddb.fromconsole    integer yes
                   1899: .El
                   1900: .Pp
                   1901: .Bl -tag -width "123456"
                   1902: .It Li ddb.radix ( DBCTL_RADIX )
                   1903: The input and output radix.
                   1904: .It Li ddb.maxoff ( DBCTL_MAXOFF )
                   1905: The maximum symbol offset.
                   1906: .It Li ddb.lines ( DBCTL_LINES )
                   1907: Number of display lines.
                   1908: .It Li ddb.tabstops ( DBCTL_TABSTOPS )
                   1909: Tab width.
                   1910: .It Li ddb.onpanic ( DBCTL_ONPANIC )
                   1911: If non-zero, DDB will be entered when the kernel panics.
                   1912: .It Li ddb.fromconsole ( DBCTL_FROMCONSOLE )
                   1913: If not zero, DDB may be entered by sending a break on a serial
                   1914: console or by a special key sequence on a graphics console.
                   1915: .\" XXX tee_msgbuf maxwidth commandonenter
                   1916: .El
                   1917: .Pp
                   1918: These MIB nodes are also available as variables from within the DDB.
                   1919: See
                   1920: .Xr ddb 4
                   1921: for more details.
                   1922: .Sh The security.* subtree ( CTL_SECURITY )
                   1923: The
                   1924: .Li security
                   1925: level contains various security-related settings for
1.2       wiz      1926: the system.
                   1927: Available settings are detailed below.
1.1       pavel    1928: .Pp
                   1929: .Bl -tag -width "123456"
                   1930: .It Li security.curtain
                   1931: If non-zero, will filter return objects according to the user-id
                   1932: requesting information about them, preventing from users any
                   1933: access to objects they don't own.
                   1934: .Pp
                   1935: At the moment, it affects
                   1936: .Xr ps 1 ,
                   1937: .Xr netstat 1
                   1938: (for
                   1939: .Dv PF_INET ,
                   1940: .Dv PF_INET6 ,
                   1941: and
                   1942: .Dv PF_UNIX
                   1943: PCBs), and
                   1944: .Xr w 1 .
1.4       elad     1945: .It Li security.models
                   1946: .Nx
                   1947: supports pluggable security models.
                   1948: Every security model used, whether if loaded as an LKM or built with the system,
                   1949: is required to add an entry to this node with at least one element,
                   1950: .Dq name ,
                   1951: indicating the name of the security model.
                   1952: .Pp
                   1953: In addition to the name, any settings and other information private to the
                   1954: security model will be available under this node.
                   1955: See
                   1956: .Xr secmodel 9
                   1957: for more information.
1.1       pavel    1958: .It Li security.pax
                   1959: Settings for PaX -- exploit mitigation features.
1.4       elad     1960: For more information on any of the PaX features, please see
                   1961: .Xr paxctl 8
                   1962: and
                   1963: .Xr security 8 .
1.1       pavel    1964: .Pp
                   1965: .Bl -tag -width "123456"
                   1966: .It Li security.pax.mprotect.enable
                   1967: Enable PaX MPROTECT restrictions.
                   1968: .Pp
                   1969: These are
                   1970: .Xr mprotect 2
1.2       wiz      1971: restrictions to better enforce a W^X policy.
                   1972: The value of this
1.1       pavel    1973: knob must be non-zero for PaX MPROTECT to be enabled, even if a
                   1974: program is set to explicit enable.
                   1975: .It Li security.pax.mprotect.global
                   1976: Specifies the default global policy for programs without an
                   1977: explicit enable/disable flag.
                   1978: .Pp
                   1979: When non-zero, all programs will get the PaX MPROTECT restrictions,
                   1980: except those exempted with
1.4       elad     1981: .Xr paxctl 8  .
1.1       pavel    1982: Otherwise, all programs will not get the PaX MPROTECT restrictions,
                   1983: except those specifically marked as such with
1.4       elad     1984: .Xr paxctl 8 .
1.1       pavel    1985: .It Li security.pax.segvguard.enable
                   1986: Enable PaX Segvguard.
                   1987: .Pp
                   1988: PaX Segvguard can detect and prevent certain exploitation attempts, where
                   1989: an attacker may try for example to brute-force function return addresses
                   1990: of respawning daemons.
                   1991: .Pp
                   1992: .Em Note :
                   1993: The
                   1994: .Nx
                   1995: interface and implementation of the Segvguard is still experimental, and may
                   1996: change in future releases.
                   1997: .It Li security.pax.segvguard.global
                   1998: Specifies the default global policy for programs without an
                   1999: explicit enable/disable flag.
                   2000: .Pp
                   2001: When non-zero, all programs will get the PaX Segvguard,
                   2002: except those exempted with
1.4       elad     2003: .Xr paxctl 8  .
1.2       wiz      2004: Otherwise, no program will get the PaX Segvguard restrictions,
1.1       pavel    2005: except those specifically marked as such with
1.4       elad     2006: .Xr paxctl 8 .
1.1       pavel    2007: .It Li security.pax.segvguard.expiry_timeout
                   2008: If the max number was not reached within this timeout (in seconds), the entry
                   2009: will expire.
                   2010: .It Li security.pax.segvguard.suspend_timeout
                   2011: Number of seconds to suspend a user from running a faulting program when the
                   2012: limit was exceeded.
                   2013: .It Li security.pax.segvguard.max_crashes
                   2014: Max number of segfaults a program can receive before suspension.
                   2015: .El
                   2016: .El
                   2017: .Sh The vendor.* subtree ( CTL_VENDOR )
                   2018: The
                   2019: .Li vendor
                   2020: toplevel name is reserved to be used by vendors who wish to
                   2021: have their own private MIB tree.
                   2022: Intended use is to store values under
                   2023: .Dq vendor.\*[Lt]yourname\*[Gt].* .
                   2024: .Sh SEE ALSO
                   2025: .Xr sysctl 3 ,
                   2026: .Xr ipsec 4 ,
                   2027: .Xr tcp 4 ,
                   2028: .Xr security 8 ,
                   2029: .Xr sysctl 8
                   2030: .Sh HISTORY
                   2031: The
                   2032: .Nm
                   2033: variables first appeared in
                   2034: .Bx 4.4 .

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