1.\" $NetBSD: sysctl.3,v 1.118 2003/06/27 17:59:33 wiz Exp $ 2.\" 3.\" Copyright (c) 1993 4.\" The Regents of the University of California. All rights reserved. 5.\" 6.\" Redistribution and use in source and binary forms, with or without 7.\" modification, are permitted provided that the following conditions 8.\" are met: 9.\" 1. Redistributions of source code must retain the above copyright 10.\" notice, this list of conditions and the following disclaimer. 11.\" 2. Redistributions in binary form must reproduce the above copyright 12.\" notice, this list of conditions and the following disclaimer in the 13.\" documentation and/or other materials provided with the distribution. 14.\" 3. All advertising materials mentioning features or use of this software 15.\" must display the following acknowledgement: 16.\" This product includes software developed by the University of 17.\" California, Berkeley and its contributors. 18.\" 4. Neither the name of the University nor the names of its contributors 19.\" may be used to endorse or promote products derived from this software 20.\" without specific prior written permission. 21.\" 22.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32.\" SUCH DAMAGE. 33.\" 34.\" @(#)sysctl.3 8.4 (Berkeley) 5/9/95 35.\" 36.Dd April 11, 2003 37.Dt SYSCTL 3 38.Os 39.Sh NAME 40.Nm sysctl 41.Nd get or set system information 42.Sh LIBRARY 43.Lb libc 44.Sh SYNOPSIS 45.In sys/param.h 46.In sys/sysctl.h 47.Ft int 48.Fn sysctl "int *name" "u_int namelen" "void *oldp" "size_t *oldlenp" "void *newp" "size_t newlen" 49.Sh DESCRIPTION 50The 51.Nm 52function retrieves system information and allows processes with 53appropriate privileges to set system information. 54The information available from 55.Nm 56consists of integers, strings, and tables. 57Information may be retrieved and set from the command interface 58using the 59.Xr sysctl 8 60utility. 61.Pp 62Unless explicitly noted below, 63.Nm 64returns a consistent snapshot of the data requested. 65Consistency is obtained by locking the destination 66buffer into memory so that the data may be copied out without blocking. 67Calls to 68.Nm 69are serialized to avoid deadlock. 70.Pp 71The state is described using a ``Management Information Base'' (MIB) 72style name, listed in 73.Fa name , 74which is a 75.Fa namelen 76length array of integers. 77.Pp 78The information is copied into the buffer specified by 79.Fa oldp . 80The size of the buffer is given by the location specified by 81.Fa oldlenp 82before the call, 83and that location gives the amount of data copied after a successful call. 84If the amount of data available is greater 85than the size of the buffer supplied, 86the call supplies as much data as fits in the buffer provided 87and returns with the error code ENOMEM. 88If the old value is not desired, 89.Fa oldp 90and 91.Fa oldlenp 92should be set to 93.Dv NULL . 94.Pp 95The size of the available data can be determined by calling 96.Nm 97with a 98.Dv NULL 99parameter for 100.Fa oldp . 101The size of the available data will be returned in the location pointed to by 102.Fa oldlenp . 103For some operations, the amount of space may change often. 104For these operations, 105the system attempts to round up so that the returned size is 106large enough for a call to return the data shortly thereafter. 107.Pp 108To set a new value, 109.Fa newp 110is set to point to a buffer of length 111.Fa newlen 112from which the requested value is to be taken. 113If a new value is not to be set, 114.Fa newp 115should be set to 116.Dv NULL 117and 118.Fa newlen 119set to 0. 120.Pp 121The top level names are defined with a CTL_ prefix in 122.Aq Pa sys/sysctl.h , 123and are as follows. 124The next and subsequent levels down are found in the include files 125listed here, and described in separate sections below. 126.Pp 127.Bl -column CTLXMACHDEPXXX "Next level namesXXXXXX" -offset indent 128.It Sy Name Next level names Description 129.It CTL\_KERN sys/sysctl.h High kernel limits 130.It CTL\_VM uvm/uvm_param.h Virtual memory 131.It CTL\_VFS sys/mount.h Filesystem 132.It CTL\_NET sys/socket.h Networking 133.It CTL\_DEBUG sys/sysctl.h Debugging 134.It CTL\_HW sys/sysctl.h Generic CPU, I/O 135.It CTL\_MACHDEP sys/sysctl.h Machine dependent 136.It CTL\_USER sys/sysctl.h User-level 137.It CTL\_DDB sys/sysctl.h In-kernel debugger 138.It CTL\_PROC sys/sysctl.h Per-process 139.It CTL\_VENDOR ? Vendor specific 140.El 141.Pp 142For example, the following retrieves the maximum number of processes allowed 143in the system: 144.Bd -literal -offset indent -compact 145int mib[2], maxproc; 146size_t len; 147.sp 148mib[0] = CTL_KERN; 149mib[1] = KERN_MAXPROC; 150len = sizeof(maxproc); 151sysctl(mib, 2, \*[Am]maxproc, \*[Am]len, NULL, 0); 152.Ed 153.sp 154To retrieve the standard search path for the system utilities: 155.Bd -literal -offset indent -compact 156int mib[2]; 157size_t len; 158char *p; 159.sp 160mib[0] = CTL_USER; 161mib[1] = USER_CS_PATH; 162sysctl(mib, 2, NULL, \*[Am]len, NULL, 0); 163p = malloc(len); 164sysctl(mib, 2, p, \*[Am]len, NULL, 0); 165.Ed 166.Sh CTL_DEBUG 167The debugging variables vary from system to system. 168A debugging variable may be added or deleted without need to recompile 169.Nm 170to know about it. 171Each time it runs, 172.Nm 173gets the list of debugging variables from the kernel and 174displays their current values. 175The system defines twenty 176.Va ( struct ctldebug ) 177variables named 178.Dv debug0 179through 180.Dv debug19 . 181They are declared as separate variables so that they can be 182individually initialized at the location of their associated variable. 183The loader prevents multiple use of the same variable by issuing errors 184if a variable is initialized in more than one place. 185For example, to export the variable 186.Dv dospecialcheck 187as a debugging variable, the following declaration would be used: 188.Bd -literal -offset indent -compact 189int dospecialcheck = 1; 190struct ctldebug debug5 = { "dospecialcheck", \*[Am]dospecialcheck }; 191.Ed 192.Sh CTL_VFS 193A distinguished second level name, VFS_GENERIC, 194is used to get general information about all filesystems. 195One of its third level identifiers is VFS_MAXTYPENUM 196that gives the highest valid filesystem type number. 197Its other third level identifier is VFS_CONF that 198returns configuration information about the filesystem 199type given as a fourth level identifier. 200The remaining second level identifiers are the 201filesystem type number returned by a 202.Xr statfs 2 203call or from VFS_CONF. 204The third level identifiers available for each filesystem 205are given in the header file that defines the mount 206argument structure for that filesystem. 207.Sh CTL_HW 208The string and integer information available for the CTL_HW level 209is detailed below. 210The changeable column shows whether a process with appropriate 211privilege may change the value. 212.Bl -column "Second level nameXXXXXX" "struct disk_sysctlXXX" -offset indent 213.It Sy Second level name Type Changeable 214.It HW\_MACHINE string no 215.It HW\_MODEL string no 216.It HW\_NCPU integer no 217.It HW\_BYTEORDER integer no 218.It HW\_PHYSMEM integer no 219.It HW\_PHYSMEM64 quad no 220.It HW\_USERMEM integer no 221.It HW\_USERMEM64 quad no 222.It HW\_PAGESIZE integer no 223.\".It HW\_DISKNAMES struct no 224.\".It HW\_DISKSTATS struct no 225.It HW\_MACHINE\_ARCH string no 226.It HW\_ALIGNBYTES integer no 227.It HW\_DISKNAMES string no 228.It HW\_DISKSTATS struct disk_sysctl no 229.It HW\_CNMAGIC string yes 230.El 231.Pp 232.Bl -tag -width "123456" 233.It Li HW_MACHINE 234The machine class. 235.It Li HW_MODEL 236The machine model. 237.It Li HW_NCPU 238The number of CPUs. 239.ne 1i 240.It Li HW_BYTEORDER 241The byteorder (4,321, or 1,234). 242.It Li HW_PHYSMEM 243The bytes of physical memory as a 32-bit integer. 244.It Li HW_PHYSMEM64 245The bytes of physical memory as a 64-bit integer. 246.It Li HW_USERMEM 247The bytes of non-kernel memory as a 32-bit integer. 248.It Li HW_USERMEM64 249The bytes of non-kernel memory as a 64-bit integer. 250.It Li HW_PAGESIZE 251The software page size. 252.It Li HW_MACHINE_ARCH 253The machine cpu class. 254.It Li HW_ALIGNBYTES 255Alignment constraint for all possible data types. 256This shows the value 257.Dv ALIGNBYTES 258in 259.Pa /usr/include/machine/param.h , 260at the kernel compilation time. 261.It Li HW_DISKNAMES 262The list of (space separated) disk device names on the system. 263.It Li HW_DISKSTATS 264Return statistical information on the disk devices on the system. 265An array of 266.Va struct disk_sysctl 267structures is returned, 268whose size depends on the current number of such objects in the system. 269The third level name is the size of the 270.Va struct disk_sysctl . 271.It Li HW_CNMAGIC 272The console magic key sequence. 273.El 274.Sh CTL_KERN 275The string and integer information available for the CTL_KERN level 276is detailed below. 277The changeable column shows whether a process with appropriate 278privilege may change the value. 279The types of data currently available are process information, 280system vnodes, the open file entries, routing table entries, 281virtual memory statistics, load average history, and clock rate 282information. 283.Bl -column "KERNXCHOWNXRESTRICTEDXXXXXX" "struct clockrateXXX" -offset indent 284.It Sy Second level name Type Changeable 285.It KERN\_ARGMAX integer no 286.It KERN\_AUTONICETIME integer yes 287.It KERN\_AUTONICEVAL integer yes 288.It KERN\_BOOTTIME struct timeval no 289.It KERN\_CCPU integer no 290.It KERN\_CLOCKRATE struct clockinfo no 291.It KERN\_CP\_TIME long[\|] no 292.It KERN\_DEFCORENAME string yes 293.It KERN\_DOMAINNAME string yes 294.It KERN\_FILE struct file no 295.It KERN\_FORKFSLEEP integer yes 296.It KERN\_FSCALE integer no 297.It KERN\_FSYNC integer no 298.It KERN\_HOSTID integer yes 299.It KERN\_HOSTNAME string yes 300.It KERN\_IOV\_MAX integer no 301.It KERN\_JOB\_CONTROL integer no 302.It KERN\_LABELOFFSET integer no 303.It KERN\_LABELSECTOR integer no 304.It KERN\_LOGIN\_NAME\_MAX integer no 305.It KERN\_LOGSIGEXIT integer yes 306.It KERN\_MAPPED\_FILES integer no 307.It KERN\_MAXFILES integer yes 308.It KERN\_MAXPARTITIONS integer no 309.It KERN\_MAXPROC integer yes 310.It KERN\_MAXPTYS integer yes 311.It KERN\_MAXVNODES integer yes 312.It KERN\_MBUF node not applicable 313.It KERN\_MEMLOCK integer no 314.It KERN\_MEMLOCK\_RANGE integer no 315.It KERN\_MEMORY\_PROTECTION integer no 316.It KERN\_MONOTONIC\_CLOCK integer no 317.It KERN\_MSGBUF char[\|] no 318.It KERN\_MSGBUFSIZE integer no 319.It KERN\_NGROUPS integer no 320.It KERN\_NTPTIME struct ntptimeval no 321.It KERN\_OSRELEASE string no 322.It KERN\_OSREV integer no 323.It KERN\_OSTYPE string no 324.It KERN\_POSIX1 integer no 325.It KERN\_POSIX\_BARRIERS integer no 326.It KERN\_POSIX\_READER\_WRITER\_LOCKS integer no 327.It KERN\_POSIX\_SEMAPHORES integer no 328.It KERN\_POSIX\_SPIN\_LOCKS integer no 329.It KERN\_POSIX\_THREADS integer no 330.It KERN\_POSIX\_TIMERS integer no 331.It KERN\_PROC struct kinfo_proc no 332.It KERN\_PROC2 struct kinfo_proc2 no 333.It KERN\_PROC\_ARGS string no 334.It KERN\_PROF node not applicable 335.It KERN\_RAWPARTITION integer no 336.It KERN\_ROOT\_DEVICE string no 337.It KERN\_RTC\_OFFSET integer no 338.It KERN\_SAVED\_IDS integer no 339.It KERN\_SECURELVL integer raise only 340.It KERN\_SYNCHRONIZED\_IO integer no 341.It KERN\_SYSVIPC\_INFO node not applicable 342.It KERN\_SYSVMSG integer no 343.It KERN\_SYSVSEM integer no 344.It KERN\_SYSVSHM integer no 345.It KERN\_TKSTAT node not applicable 346.It KERN\_VERSION string no 347.It KERN\_VNODE struct vnode no 348.El 349.ne 1i 350.Pp 351.Bl -tag -width "123456" 352.It Li KERN_ARGMAX 353The maximum bytes of argument to 354.Xr execve 2 . 355.It Li KERN_AUTONICETIME 356The number of seconds of cpu-time a non-root process may accumulate before 357having its priority lowered from the default to the value of KERN_AUTONICEVAL. 358If set to 0, automatic lowering of priority is not performed, and if set to \-1 359all non-root processes are immediately lowered. 360.It Li KERN_AUTONICEVAL 361The priority assigned for automatically niced processes. 362.It Li KERN_BOOTTIME 363A 364.Va struct timeval 365structure is returned. 366This structure contains the time that the system was booted. 367.It Li KERN_CCPU 368The scheduler exponential decay value. 369.It Li KERN_CLOCKRATE 370A 371.Va struct clockinfo 372structure is returned. 373This structure contains the clock, statistics clock and profiling clock 374frequencies, the number of micro-seconds per hz tick, and the clock 375skew rate. 376.It Li KERN_CP_TIME 377Return an array if CPUSTATES longs is returned. 378This array contains the 379number of clock ticks spent in different CPU states. 380.It Li KERN_DEFCORENAME 381Default template for the name of core dump files (see also PROC_PID_CORENAME 382in the per-process variables CTL_PROC, and 383.Xr core 5 384for format of this template). 385The default value is 386.Nm %n.core 387and can be changed with the kernel configuration option 388.Cd options DEFCORENAME 389(see 390.Xr options 4 391). 392.It Li KERN_DOMAINNAME 393Get or set the YP domain name. 394.It Li KERN_FILE 395Return the entire file table. 396The returned data consists of a single 397.Va struct filehead 398followed by an array of 399.Va struct file , 400whose size depends on the current number of such objects in the system. 401.It Li KERN_FSCALE 402The kernel fixed-point scale factor. 403.It Li KERN_FORKFSLEEP 404If 405.Xr fork 2 406system call fails due to limit on number of processes (either 407the global maxproc limit or user's one), wait for this many 408miliseconds before returning 409.Er EAGAIN 410error to process. 411Useful to keep heavily forking runaway processes in bay. 412Default zero (no sleep). 413Maximum is 20 seconds. 414.It Li KERN_FSYNC 415Return 1 if the POSIX 1003.1b File Synchronization Option is available 416on this system, 417otherwise 0. 418.It Li KERN_HOSTID 419Get or set the host id. 420.It Li KERN_HOSTNAME 421Get or set the hostname. 422.It Li KERN_IOV_MAX 423Return the maximum number of 424.Va iovec 425structures that a process has available for use with 426.Xr preadv 2 , 427.Xr pwritev 2 , 428.Xr readv 2 , 429.Xr recvmsg 2 , 430.Xr sendmsg 2 431and 432.Xr writev 2 . 433.It Li KERN_JOB_CONTROL 434Return 1 if job control is available on this system, otherwise 0. 435.It Li KERN_LABELOFFSET 436The offset within the sector specified by KERN_LABELSECTOR of the 437.Xr disklabel 5 . 438.It Li KERN_LABELSECTOR 439The sector number containing the 440.Xr disklabel 5 . 441.It Li KERN_LOGIN_NAME_MAX 442The size of the storage required for a login name, in bytes, 443including the terminating NUL. 444.It Li KERN_LOGSIGEXIT 445If this flag is non-zero, the kernel will 446.Xr log 9 447all process exits due to signals which create a 448.Xr core 5 449file, and whether the coredump was created. 450.It Li KERN_MAPPED_FILES 451Returns 1 if the POSIX 1003.1b Memory Mapped Files Option is available 452on this system, 453otherwise 0. 454.It Li KERN_MAXFILES 455The maximum number of open files that may be open in the system. 456.It Li KERN_MAXPARTITIONS 457The maximum number of partitions allowed per disk. 458.It Li KERN_MAXPROC 459The maximum number of simultaneous processes the system will allow. 460.It Li KERN_MAXPTYS 461The maximum number of pseudo terminals. 462This value can be both raised and lowered, though it cannot 463be set lower than number of currently used ptys. 464See also 465.Xr pty 4 . 466.It Li KERN_MAXVNODES 467The maximum number of vnodes available on the system. 468This can only be raised. 469.It Li KERN_MBUF 470Return information about the mbuf control variables. 471the third level names for the mbuf variables are detailed below. 472The changeable column shows whether a process with appropriate 473privilege may change the value. 474.Bl -column "MBUFXNMBCLUSTERSXXX" "struct integerXXX" -offset indent 475.It Sy Third level name Type Changeable 476.It MBUF\_MSIZE integer yes 477.It MBUF\_MCLBYTES integer yes 478.It MBUF\_NMBCLUSTERS integer yes 479.It MBUF\_MBLOWAT integer yes 480.It MBUF\_MCLLOWAT integer yes 481.El 482.Pp 483The variables are as follows: 484.Bl -tag -width "123456" 485.It Li MBUF_MSIZE 486The mbuf base size. 487.It Li MBUF_MCLBYTES 488The mbuf cluster size. 489.It Li MBUF_NMBCLUSTERS 490The limit on the number of mbuf clusters. 491The variable can only be increased, and only increased on machines with 492direct-mapped pool pages 493.It Li MBUF_MBLOWAT 494The mbuf low water mark. 495.It Li MBUF_MCLLOWAT 496The mbuf cluster low water mark. 497.El 498.It Li KERN_MEMLOCK 499Returns 1 if the POSIX 1003.1b Process Memory Locking Option is available 500on this system, 501otherwise 0. 502.It Li KERN_MEMLOCK_RANGE 503Returns 1 if the POSIX 1003.1b Range Memory Locking Option is available 504on this system, 505otherwise 0. 506.It Li KERN_MEMORY_PROTECTION 507Returns 1 if the POSIX 1003.1b Memory Protection Option is available 508on this system, 509otherwise 0. 510.It Li KERN_MONOTONIC_CLOCK 511Returns the standard version the implementation of the POSIX 1003.1b 512Monotonic Clock Option conforms to, 513otherwise 0. 514.It Li KERN_MSGBUF 515The kernel message buffer, rotated so that the head of the circular kernel 516message buffer is returned at the start of the buffer specified by 517.Fa oldp . 518The returned data may contain NUL bytes. 519.It Li KERN_MSGBUFSIZE 520The maximum number of characters that the kernel message buffer can hold. 521.It Li KERN_NGROUPS 522The maximum number of supplemental groups. 523.It Li KERN_NO_TRUNC 524Return 1 if file names longer than KERN_NAME_MAX are truncated. 525.It Li KERN_NTPTIME 526A 527.Va struct ntptimeval 528structure is returned. 529This structure contains data used by the 530.Xr ntpd 8 531program. 532.It Li KERN_OSRELEASE 533The system release string. 534.It Li KERN_OSREV 535The system revision string. 536.It Li KERN_OSTYPE 537The system type string. 538.It Li KERN_PATH_MAX 539The maximum number of bytes in a pathname. 540.It Li KERN_POSIX1 541The version of ISO/IEC 9945 (POSIX 1003.1) with which the system 542attempts to comply. 543.It Li KERN_POSIX_BARRIERS 544The version of 545.St -p1003.1 546and its 547Barriers 548option to which the system attempts to conform, 549otherwise 0. 550.It Li KERN_POSIX_READER_WRITER_LOCKS 551The version of 552.St -p1003.1 553and its 554Read-Write Locks 555option to which the system attempts to conform, 556otherwise 0. 557.It Li KERN_POSIX_SEMAPHORES 558The version of 559.St -p1003.1 560and its 561Semaphores 562option to which the system attempts to conform, 563otherwise 0. 564.It Li KERN_POSIX_SPIN_LOCKS 565The version of 566.St -p1003.1 567and its 568Spin Locks 569option to which the system attempts to conform, 570otherwise 0. 571.It Li KERN_POSIX_THREADS 572The version of 573.St -p1003.1 574and its 575Threads 576option to which the system attempts to conform, 577otherwise 0. 578.It Li KERN_POSIX_TIMERS 579The version of 580.St -p1003.1 581and its 582Timers 583option to which the system attempts to conform, 584otherwise 0. 585.It Li KERN_PROC 586Return the entire process table, or a subset of it. 587An array of 588.Va struct kinfo_proc 589structures is returned, 590whose size depends on the current number of such objects in the system. 591The third and fourth level names are as follows: 592.Bl -column "Third level nameXXXXXX" "Fourth level is:XXXXXX" -offset indent 593.It Sy Third level name Fourth level is: 594.It KERN\_PROC\_ALL None 595.It KERN\_PROC\_PID A process ID 596.It KERN\_PROC\_PGRP A process group 597.It KERN\_PROC\_SESSION A session ID 598.It KERN\_PROC\_TTY A tty device 599.It KERN\_PROC\_UID A user ID 600.It KERN\_PROC\_RUID A real user ID 601.It KERN\_PROC\_GID A group ID 602.It KERN\_PROC\_RGID A real group ID 603.El 604.It Li KERN_PROC2 605As for KERN_PROC, but an array of 606.Va struct kinfo_proc2 607structures are returned. 608The fifth level name is the size of the 609.Va struct kinfo_proc2 610and the sixth level name is the number of structures to return. 611.It Li KERN_PROC_ARGS 612Return the argv or environment strings (or the number thereof) 613of a process. 614Multiple strings are returned separated by NUL characters. 615The third level name is the process ID. 616The fourth level name is as follows: 617.Bl -column "Third level nameXXXXXX" -offset indent 618.It KERN\_PROC\_ARGV The argv strings 619.It KERN\_PROC\_NARGV The number of argv strings 620.It KERN\_PROC\_ENV The environ strings 621.It KERN\_PROC\_NENV The number of environ strings 622.El 623.It Li KERN_PROF 624Return profiling information about the kernel. 625If the kernel is not compiled for profiling, 626attempts to retrieve any of the KERN_PROF values will 627fail with EOPNOTSUPP. 628The third level names for the string and integer profiling information 629is detailed below. 630The changeable column shows whether a process with appropriate 631privilege may change the value. 632.Bl -column "GPROFXGMONPARAMXXX" "struct gmonparamXXX" -offset indent 633.It Sy Third level name Type Changeable 634.It GPROF\_STATE integer yes 635.It GPROF\_COUNT u_short[\|] yes 636.It GPROF\_FROMS u_short[\|] yes 637.It GPROF\_TOS struct tostruct yes 638.It GPROF\_GMONPARAM struct gmonparam no 639.El 640.Pp 641The variables are as follows: 642.Bl -tag -width "123456" 643.It Li GPROF_STATE 644Returns GMON_PROF_ON or GMON_PROF_OFF to show that profiling 645is running or stopped. 646.It Li GPROF_COUNT 647Array of statistical program counter counts. 648.It Li GPROF_FROMS 649Array indexed by program counter of call-from points. 650.It Li GPROF_TOS 651Array of 652.Va struct tostruct 653describing destination of calls and their counts. 654.It Li GPROF_GMONPARAM 655Structure giving the sizes of the above arrays. 656.El 657.It Li KERN_RAWPARTITION 658The raw partition of a disk (a == 0). 659.It Li KERN_ROOT_DEVICE 660The name of the root device. 661.It Li KERN_RTC_OFFSET 662Return the offset of real time clock from UTC in minutes. 663.It Li KERN_SAVED_IDS 664Returns 1 if saved set-group and saved set-user ID is available. 665.It Li KERN_SECURELVL 666The system security level. 667This level may be raised by processes with appropriate privilege. 668It may only be lowered by process 1. 669.It Li KERN_SYNCHRONIZED_IO 670Returns 1 if the POSIX 1003.1b Synchronized I/O Option is available 671on this system, 672otherwise 0. 673.It Li KERN_SYSVIPC_INFO 674Return System V style IPC configuration and run-time information. 675The third level name selects the System V style IPC facility. 676.Bl -column "KERN_SYSVIPC_MSG_INFOXXX" "struct shm_sysctl_infoXXX" -offset indent 677.It Sy Third level name Type 678.It KERN\_SYSVIPC\_MSG\_INFO struct msg_sysctl_info 679.It KERN\_SYSVIPC\_SEM\_INFO struct sem_sysctl_info 680.It KERN\_SYSVIPC\_SHM\_INFO struct shm_sysctl_info 681.El 682.Pp 683.Bl -tag -width "123456" 684.It Li KERN_SYSVIPC_MSG_INFO 685Return information on the System V style message facility. 686The 687.Sy msg_sysctl_info 688structure is defined in 689.Aq Pa sys/msg.h . 690.It Li KERN_SYSVIPC_SEM_INFO 691Return information on the System V style semaphore facility. 692The 693.Sy sem_sysctl_info 694structure is defined in 695.Aq Pa sys/sem.h . 696.It Li KERN_SYSVIPC_SHM_INFO 697Return information on the System V style shared memory facility. 698The 699.Sy shm_sysctl_info 700structure is defined in 701.Aq Pa sys/shm.h . 702.El 703.It Li KERN_SYSVMSG 704Returns 1 if System V style message queue functionality is available 705on this system, 706otherwise 0. 707.It Li KERN_SYSVSEM 708Returns 1 if System V style semaphore functionality is available 709on this system, 710otherwise 0. 711.It Li KERN_SYSVSHM 712Returns 1 if System V style share memory functionality is available 713on this system, 714otherwise 0. 715.It Li KERN_TKSTAT 716Return information about the number of characters sent and received 717on ttys. 718The third level names for the tty statistic variables are detailed below. 719The changeable column shows whether a process 720with appropriate privilege may change the value. 721.Bl -column "KERNXTKSTATXRAWCCXXX" "struct integerXXX" -offset indent 722.It Sy Third level name Type Changeable 723.It KERN\_TKSTAT\_NIN quad no 724.It KERN\_TKSTAT\_NOUT quad no 725.It KERN\_TKSTAT\_CANCC quad no 726.It KERN\_TKSTAT\_RAWCC quad no 727.El 728.Pp 729The variables are as follows: 730.Bl -tag -width "123456" 731.It Li KERN_TKSTAT_NIN 732The total number of input characters. 733.It Li KERN_TKSTAT_NOUT 734The total number of output characters. 735.It Li KERN_TKSTAT_CANCC 736The number of canonical input characters. 737.It Li KERN_TKSTAT_RAWCC 738The number of raw input characters. 739.El 740.It Li KERN_VERSION 741The system version string. 742.It Li KERN_VNODE 743Return the entire vnode table. 744Note, the vnode table is not necessarily a consistent snapshot of 745the system. 746The returned data consists of an array whose size depends on the 747current number of such objects in the system. 748Each element of the array contains the kernel address of a vnode 749.Va struct vnode * 750followed by the vnode itself 751.Va struct vnode . 752.El 753.Sh CTL_MACHDEP 754The set of variables defined is architecture dependent. 755Most architectures define at least the following variables. 756.Bl -column "CONSOLE_DEVICEXXX" "integerXXX" -offset indent 757.It Sy Second level name Type Changeable 758.It Li CPU_CONSDEV dev_t no 759.El 760.Sh CTL_NET 761The string and integer information available for the CTL_NET level 762is detailed below. 763The changeable column shows whether a process with appropriate 764privilege may change the value. 765.Bl -column "Second level nameXXXXXX" "routing messagesXXX" -offset indent 766.It Sy Second level name Type Changeable 767.It PF\_ROUTE routing messages no 768.It PF\_INET IPv4 values yes 769.It PF\_INET6 IPv6 values yes 770.It PF\_KEY IPsec key management values yes 771.El 772.Pp 773.Bl -tag -width "123456" 774.It Li PF_ROUTE 775Return the entire routing table or a subset of it. 776The data is returned as a sequence of routing messages (see 777.Xr route 4 778for the header file, format and meaning). 779The length of each message is contained in the message header. 780.Pp 781The third level name is a protocol number, which is currently always 0. 782The fourth level name is an address family, which may be set to 0 to 783select all address families. 784The fifth and sixth level names are as follows: 785.Bl -column "Fifth level nameXXXXXX" "Sixth level is:XXX" -offset indent 786.It Sy Fifth level name Sixth level is: 787.It NET\_RT\_FLAGS rtflags 788.It NET\_RT\_DUMP None 789.It NET\_RT\_IFLIST None 790.El 791.It Li PF_INET 792Get or set various global information about the IPv4 793.Pq Internet Protocol version 4 . 794The third level name is the protocol. 795The fourth level name is the variable name. 796The currently defined protocols and names are: 797.Bl -column "Protocol name" "Variable nameXX" "integer" "yes" -offset indent 798.It Sy Protocol name Variable name Type Changeable 799.It ip forwarding integer yes 800.It ip redirect integer yes 801.It ip ttl integer yes 802.It ip forwsrcrt integer yes 803.It ip directed-broadcast integer yes 804.It ip allowsrcrt integer yes 805.It ip subnetsarelocal integer yes 806.It ip mtudisc integer yes 807.It ip anonportmin integer yes 808.It ip anonportmax integer yes 809.It ip mtudisctimeout integer yes 810.It ip gifttl integer yes 811.It ip grettl integer yes 812.It ip lowportmin integer yes 813.It ip lowportmax integer yes 814.It ip maxfragpacket integer yes 815.It ip checkinterface integer yes 816.It icmp maskrepl integer yes 817.It icmp errppslimit integer yes 818.It icmp rediraccept integer yes 819.It icmp redirtimeout integer yes 820.It tcp rfc1323 integer yes 821.It tcp sendspace integer yes 822.It tcp recvspace integer yes 823.It tcp mssdflt integer yes 824.It tcp syn_cache_limit integer yes 825.It tcp syn_bucket_limit integer yes 826.It tcp syn_cache_interval integer yes 827.It tcp init_win integer yes 828.It tcp init_win_local integer yes 829.It tcp mss_ifmtu integer yes 830.It tcp sack integer yes 831.It tcp win_scale integer yes 832.It tcp timestamps integer yes 833.It tcp compat_42 integer yes 834.It tcp cwm integer yes 835.It tcp cwm_burstsize integer yes 836.It tcp ack_on_push integer yes 837.It tcp keepidle integer yes 838.It tcp keepintvl integer yes 839.It tcp keepcnt integer yes 840.It tcp slowhz integer no 841.It tcp newreno integer yes 842.It tcp log_refused integer yes 843.It tcp rstppslimit integer yes 844.It tcp ident struct no 845.It udp checksum integer yes 846.It udp sendspace integer yes 847.It udp recvspace integer yes 848.El 849.Pp 850The variables are as follows: 851.Bl -tag -width "123456" 852.It Li ip.forwarding 853Returns 1 when IP forwarding is enabled for the host, 854meaning that the host is acting as a router. 855.It Li ip.redirect 856Returns 1 when ICMP redirects may be sent by the host. 857This option is ignored unless the host is routing IP packets, 858and should normally be enabled on all systems. 859.It Li ip.ttl 860The maximum time-to-live (hop count) value for an IP packet sourced by 861the system. 862This value applies to normal transport protocols, not to ICMP. 863.It Li ip.forwsrcrt 864Returns 1 when forwarding of source-routed packets is enabled for 865the host. 866This value may only be changed if the kernel security level is less than 1. 867.It Li ip.directed-broadcast 868Returns 1 if directed broadcast behavior is enabled for the host. 869.It Li ip.allowsrcrt 870Returns 1 if the host accepts source routed packets. 871.It Li ip.subnetsarelocal 872Returns 1 if subnets are to be considered local addresses. 873.It Li ip.mtudisc 874Returns 1 if Path MTU Discovery is enabled. 875.It Li ip.anonportmin 876The lowest port number to use for TCP and UDP ephemeral port allocation. 877This cannot be set to less than 1024 or greater than 65535. 878.It Li ip.anonportmax 879The highest port number to use for TCP and UDP ephemeral port allocation. 880This cannot be set to less than 1024 or greater than 65535, and must 881be greater than 882.Li ip.anonportmin . 883.It Li ip.mtudisctimeout 884Returns the number of seconds in which a route added by the Path MTU 885Discovery engine will time out. 886When the route times out, the Path 887MTU Discovery engine will attempt to probe a larger path MTU. 888.It Li ip.gifttl 889The maximum time-to-live (hop count) value for an IPv4 packet generated by 890.Xr gif 4 891tunnel interface. 892.It Li ip.grettl 893The maximum time-to-live (hop count) value for an IPv4 packet generated by 894.Xr gre 4 895tunnel interface. 896.It Li ip.lowportmin 897The lowest port number to use for TCP and UDP reserved port allocation. 898This cannot be set to less than 0 or greater than 1024, and must 899be smaller than 900.Li ip.lowportmax . 901.It Li ip.lowportmax 902The highest port number to use for TCP and UDP reserved port allocation. 903This cannot be set to less than 0 or greater than 1024, and must 904be greater than 905.Li ip.lowportmin . 906.It Li ip.maxfragpackets 907The maximum number of fragmented packets the node will accept. 9080 means that the node will not accept any fragmented packets. 909\-1 means that the node will accept as many fragmented packets as it receives. 910The flag is provided basically for avoiding possible DoS attacks. 911.It Li ip.checkinterface 912If set to non-zero, the host will reject packets addressed to it that arrive 913on an interface not bound to that address. Currently, this must be disabled 914if ipnat is used to translate the destination address to another local 915interface, or if addresses are added to the loopback interface instead of 916the interface where the packets for those packets are received. 917.It Li icmp.maskrepl 918Returns 1 if ICMP network mask requests are to be answered. 919.It Li icmp.errppslimit 920The variable specifies the maximum number of outgoing ICMP error messages, 921per second. 922ICMP error messages that exceeded the value are subject to rate limitation 923and will not go out from the node. 924Negative value disables rate limitation. 925.It Li icmp.rediraccept 926If set to non-zero, the host will accept ICMP redirect packets. 927Note that routers will never accept ICMP redirect packets, 928and the variable is meaningful on IP hosts only. 929.It Li icmp.redirtimeout 930The variable specifies lifetime of routing entries generated by incoming 931ICMP redirect. 932This defaults to 600 seconds. 933.It Li tcp.rfc1323 934Returns 1 if RFC1323 extensions to TCP are enabled. 935.It Li tcp.sendspace 936Returns the default TCP send buffer size. 937.It Li tcp.recvspace 938Returns the default TCP receive buffer size. 939.It Li tcp.mssdflt 940Returns the default maximum segment size both advertized to the peer 941and to use when the peer does not advertize a maximum segment size to 942us during connection setup. 943Do not change this value unless you really know what you are doing. 944.It Li tcp.syn_cache_limit 945Returns the maximum number of entries allowed in the TCP compressed state 946engine. 947.It Li tcp.syn_bucket_limit 948Returns the maximum number of entries allowed per hash bucket in the TCP 949compressed state engine. 950.It Li tcp.syn_cache_interval 951Returns the TCP compressed state engine's timer interval. 952.It Li tcp.init_win 953Returns a value indicating the TCP initial congestion window. 954If this value is 0, an auto-tuning algorithm designed to use an initial 955window of approximately 4K bytes is in use. 956Otherwise, this value indicates a fixed number of packets. 957.It Li tcp.init_win_local 958Like 959.Li tcp.init_win , 960but used when communicating with hosts on a local network. 961.It Li tcp.mss_ifmtu 962Returns 1 if TCP calculates the outgoing maximum segment size based on 963the MTU of the appropriate interface. 964Otherwise, it is calculated based on the greater of the MTU of the 965interface, and the largest (non-loopback) interface MTU on the system. 966.It Li tcp.sack 967TCP Selective ACKnowledgement (RFC 2018) is not implemented in 968.Nx 969at this time. 970Changing this value will have no effect. 971.It Li tcp.win_scale 972If rfc1323 is enabled, a value of 1 indicates RFC1323 window scale options, 973for increasing the TCP window size, are enabled. 974.It Li tcp.timestamps 975If rfc1323 is enabled, a value of 1 indicates RFC1323 time stamp options, 976used for measuring TCP round trip times, are enabled. 977.It Li tcp.compat_42 978Returns 1 if work-arounds for bugs in the 4.2BSD TCP implementation are 979enabled. 980Use of this option is not recommended, although it may be 981required in order to communicate with extremely old TCP implementations. 982.It Li tcp.cwm 983Returns 1 if use of the Hughes/Touch/Heidemann Congestion Window Monitoring 984algorithm is enabled. 985This algorithm prevents line-rate bursts of packets that could 986otherwise occur when data begins flowing on an idle TCP connection. 987These line-rate bursts can contribute to network and router congestion. 988This can be particularly useful on World Wide Web servers 989which support HTTP/1.1, which has lingering connections. 990.It Li tcp.cwm_burstsize 991Returns the Congestion Window Monitoring allowed burst size, in terms 992of packet count. 993.It Li tcp.ack_on_push 994Returns 1 if TCP is to immediately transmit an ACK upon reception of 995a packet with PUSH set. 996This can avoid losing a round trip time in some rare situations, 997but has the caveat of potentially defeating TCP's delayed ACK algorithm. 998Use of this option is generally not recommended, but 999the variable exists in case your configuration really needs it. 1000.It Li tcp.keepidle 1001Time a connection must be idle before keepalives are sent (if keepalives 1002are enabled for the connection). 1003See also tcp.slowhz. 1004.It Li tcp.keepintvl 1005Time after a keepalive probe is sent until, in the absence of any response, 1006another probe is sent. 1007See also tcp.slowhz. 1008.It Li tcp.keepcnt 1009Number of keepalive probes sent before declaring a connection dead. 1010If set to zero, there is no limit; 1011keepalives will be sent until some kind of 1012response is received from the peer. 1013.It Li tcp.slowhz 1014The units for tcp.keepidle and tcp.keepintvl; those variables are in ticks 1015of a clock that ticks tcp.slowhz times per second. 1016(That is, their values 1017must be divided by the tcp.slowhz value to get times in seconds.) 1018.It Li tcp.newreno 1019Returns 1 if the use of J. 1020Hoe's NewReno congestion control algorithm is enabled. 1021This algorithm improves the start-up behavior of TCP connections. 1022.It Li tcp.log_refused 1023Returns 1 if refused TCP connections to the host will be logged. 1024.It Li tcp.rstppslimit 1025The variable specifies the maximum number of outgoing TCP RST packets, 1026per second. 1027TCP RST packet that exceeded the value are subject to rate limitation 1028and will not go out from the node. 1029Negative value disables rate limitation. 1030.It Li udp.checksum 1031Returns 1 when UDP checksums are being computed and checked. 1032Disabling UDP checksums is strongly discouraged. 1033.It Li udp.sendspace 1034Returns the default UDP send buffer size. 1035.It Li udp.recvspace 1036Returns the default UDP receive buffer size. 1037.El 1038.Pp 1039For variables net.*.ipsec, please refer to 1040.Xr ipsec 4 . 1041.It Li PF_INET6 1042Get or set various global information about the IPv6 1043.Pq Internet Protocol version 6 . 1044The third level name is the protocol. 1045The fourth level name is the variable name. 1046The currently defined protocols and names are: 1047.Bl -column "Protocol name" "Variable nameXX" "integer" "yes" -offset indent 1048.It Sy Protocol name Variable name Type Changeable 1049.It ip6 forwarding integer yes 1050.It ip6 redirect integer yes 1051.It ip6 hlim integer yes 1052.It ip6 maxfragpackets integer yes 1053.It ip6 accept_rtadv integer yes 1054.It ip6 keepfaith integer yes 1055.It ip6 log_interval integer yes 1056.It ip6 hdrnestlimit integer yes 1057.It ip6 dad_count integer yes 1058.It ip6 auto_flowlabel integer yes 1059.It ip6 defmcasthlim integer yes 1060.It ip6 gif_hlim integer yes 1061.It ip6 kame_version string no 1062.It ip6 use_deprecated integer yes 1063.It ip6 rr_prune integer yes 1064.It ip6 v6only integer yes 1065.It ip6 anonportmin integer yes 1066.It ip6 anonportmax integer yes 1067.It ip6 lowportmin integer yes 1068.It ip6 lowportmax integer yes 1069.It ip6 maxfrags integer yes 1070.It icmp6 rediraccept integer yes 1071.It icmp6 redirtimeout integer yes 1072.It icmp6 nd6_prune integer yes 1073.It icmp6 nd6_delay integer yes 1074.It icmp6 nd6_umaxtries integer yes 1075.It icmp6 nd6_mmaxtries integer yes 1076.It icmp6 nd6_useloopback integer yes 1077.It icmp6 nodeinfo integer yes 1078.It icmp6 errppslimit integer yes 1079.It icmp6 nd6_maxnudhint integer yes 1080.It icmp6 mtudisc_hiwat integer yes 1081.It icmp6 mtudisc_lowat integer yes 1082.It icmp6 nd6_debug integer yes 1083.It udp6 sendspace integer yes 1084.It udp6 recvspace integer yes 1085.El 1086.Pp 1087The variables are as follows: 1088.Bl -tag -width "123456" 1089.It Li ip6.forwarding 1090Returns 1 when IPv6 forwarding is enabled for the node, 1091meaning that the node is acting as a router. 1092Returns 0 when IPv6 forwarding is disabled for the node, 1093meaning that the node is acting as a host. 1094IPv6 specification defines node behavior for 1095.Dq router 1096case and 1097.Dq host 1098case quite differently, and changing this variable during operation 1099may cause serious trouble. 1100It is recommended to configure the variable at bootstrap time, 1101and bootstrap time only. 1102.It Li ip6.redirect 1103Returns 1 when ICMPv6 redirects may be sent by the node. 1104This option is ignored unless the node is routing IP packets, 1105and should normally be enabled on all systems. 1106.It Li ip6.hlim 1107The default hop limit value for an IPv6 unicast packet sourced by the node. 1108This value applies to all the transport protocols on top of IPv6. 1109There are APIs to override the value, as documented in 1110.Xr ip6 4 . 1111.It Li ip6.maxfragpackets 1112The maximum number of fragmented packets the node will accept. 11130 means that the node will not accept any fragmented packets. 1114\-1 means that the node will accept as many fragmented packets as it receives. 1115The flag is provided basically for avoiding possible DoS attacks. 1116.It Li ip6.accept_rtadv 1117If set to non-zero, the node will accept ICMPv6 router advertisement packets 1118and autoconfigures address prefixes and default routers. 1119The node must be a host 1120.Pq not a router 1121for the option to be meaningful. 1122.It Li ip6.keepfaith 1123If set to non-zero, it enables 1124.Dq FAITH 1125TCP relay IPv6-to-IPv4 translator code in the kernel. 1126Refer 1127.Xr faith 4 1128and 1129.Xr faithd 8 1130for detail. 1131.It Li ip6.log_interval 1132The variable controls amount of logs generated by IPv6 packet 1133forwarding engine, by setting interval between log output 1134.Pq in seconds . 1135.It Li ip6.hdrnestlimit 1136The number of IPv6 extension headers permitted on incoming IPv6 packets. 1137If set to 0, the node will accept as many extension headers as possible. 1138.It Li ip6.dad_count 1139The variable configures number of IPv6 DAD 1140.Pq duplicated address detection 1141probe packets. 1142The packets will be generated when IPv6 interface addresses are configured. 1143.It Li ip6.auto_flowlabel 1144On connected transport protocol packets, 1145fill IPv6 flowlabel field to help intermediate routers to identify packet flows. 1146.It Li ip6.defmcasthlim 1147The default hop limit value for an IPv6 multicast packet sourced by the node. 1148This value applies to all the transport protocols on top of IPv6. 1149There are APIs to override the value, as documented in 1150.Xr ip6 4 . 1151.It Li ip6.gif_hlim 1152The maximum hop limit value for an IPv6 packet generated by 1153.Xr gif 4 1154tunnel interface. 1155.It Li ip6.kame_version 1156The string identifies the version of KAME IPv6 stack implemented in the kernel. 1157.It Li ip6.use_deprecated 1158The variable controls use of deprecated address, specified in RFC2462 5.5.4. 1159.It Li ip6.rr_prune 1160The variable specifies interval between IPv6 router renumbering prefix 1161babysitting, in seconds. 1162.It Li ip6.v6only 1163The variable specifies initial value for 1164.Dv IPV6_V6ONLY 1165socket option for 1166.Dv AF_INET6 1167socket. 1168Please refer to 1169.Xr ip6 4 1170for detail. 1171.It Li ip6.anonportmin 1172The lowest port number to use for TCP and UDP ephemeral port allocation. 1173This cannot be set to less than 1024 or greater than 65535. 1174.It Li ip6.anonportmax 1175The highest port number to use for TCP and UDP ephemeral port allocation. 1176This cannot be set to less than 1024 or greater than 65535, and must 1177be greater than 1178.Li ip6.anonportmin . 1179.It Li ip6.lowportmin 1180The lowest port number to use for TCP and UDP reserved port allocation. 1181This cannot be set to less than 0 or greater than 1024, and must 1182be smaller than 1183.Li ip6.lowportmax . 1184.It Li ip6.lowportmax 1185The highest port number to use for TCP and UDP reserved port allocation. 1186This cannot be set to less than 0 or greater than 1024, and must 1187be greater than 1188.Li ip6.lowportmin . 1189.It Li ip6.maxfrags 1190The maximum number of fragments the node will accept. 11910 means that the node will not accept any fragments. 1192\-1 means that the node will accept as many fragments as it receives. 1193The flag is provided basically for avoiding possible DoS attacks. 1194.It Li icmp6.rediraccept 1195If set to non-zero, the host will accept ICMPv6 redirect packets. 1196Note that IPv6 routers will never accept ICMPv6 redirect packets, 1197and the variable is meaningful on IPv6 hosts 1198.Pq non-router 1199only. 1200.It Li icmp6.redirtimeout 1201The variable specifies lifetime of routing entries generated by incoming 1202ICMPv6 redirect. 1203.It Li icmp6.nd6_prune 1204The variable specifies interval between IPv6 neighbor cache babysitting, 1205in seconds. 1206.It Li icmp6.nd6_delay 1207The variable specifies 1208.Dv DELAY_FIRST_PROBE_TIME 1209timing constant in IPv6 neighbor discovery specification 1210.Pq RFC2461 , 1211in seconds. 1212.It Li icmp6.nd6_umaxtries 1213The variable specifies 1214.Dv MAX_UNICAST_SOLICIT 1215constant in IPv6 neighbor discovery specification 1216.Pq RFC2461 . 1217.It Li icmp6.nd6_mmaxtries 1218The variable specifies 1219.Dv MAX_MULTICAST_SOLICIT 1220constant in IPv6 neighbor discovery specification 1221.Pq RFC2461 . 1222.It Li icmp6.nd6_useloopback 1223If set to non-zero, kernel IPv6 stack will use loopback interface for 1224local traffic. 1225.It Li icmp6.nodeinfo 1226The variable enables responses to ICMPv6 node information queries. 1227If you set the variable to 0, responses will not be generated for 1228ICMPv6 node information queries. 1229Since node information queries can have a security impact, it is 1230possible to fine tune which responses should be answered. 1231Two separate bits can be set. 1232.Bl -tag -width "12345" 1233.It 1 1234Respond to ICMPv6 FQDN queries, e.g. 1235.Li ping6 -w . 1236.It 2 1237Respond to ICMPv6 node addresses queries, e.g. 1238.Li ping6 -a . 1239.El 1240.It Li icmp6.errppslimit 1241The variable specifies the maximum number of outgoing ICMPv6 error messages, 1242per second. 1243ICMPv6 error messages that exceeded the value are subject to rate limitation 1244and will not go out from the node. 1245Negative value disables rate limitation. 1246.It Li icmp6.nd6_maxnudhint 1247IPv6 neighbor discovery permits upper layer protocols to supply reachability 1248hints, to avoid unnecessary neighbor discovery exchanges. 1249The variable defines the number of consecutive hints the neighbor discovery 1250layer will take. 1251For example, by setting the variable to 3, neighbor discovery layer 1252will take 3 consecutive hints in maximum. 1253After receiving 3 hints, neighbor discovery layer will perform 1254normal neighbor discovery process. 1255.It Li icmp6.mtudisc_hiwat 1256.It Li icmp6.mtudisc_lowat 1257The variables define the maximum number of routing table entries, 1258created due to path MTU discovery 1259.Pq prevents denial-of-service attacks with ICMPv6 too big messages . 1260When IPv6 path MTU discovery happens, we keep path MTU information into 1261the routing table. 1262If the number of routing table entries exceed the value, 1263the kernel will not attempt to keep the path MTU information. 1264.Li icmp6.mtudisc_hiwat 1265is used when we have verified ICMPv6 too big messages. 1266.Li icmp6.mtudisc_lowat 1267is used when we have unverified ICMPv6 too big messages. 1268Verification is performed by using address/port pairs kept in connected pcbs. 1269Negative value disables the upper limit. 1270.It Li icmp6.nd6_debug 1271If set to non-zero, kernel IPv6 neighbor discovery code will generate 1272debugging messages. 1273The debug outputs are useful to diagnose IPv6 interoperability issues. 1274The flag must be set to 0 for normal operation. 1275.El 1276.Pp 1277We reuse net.*.tcp for 1278.Tn TCP 1279over 1280.Tn IPv6 , 1281and therefore we do not have variables net.*.tcp6. 1282Variables net.inet6.udp6 have identical meaning to net.inet.udp. 1283Please refer to 1284.Li PF_INET 1285section above. 1286For variables net.*.ipsec6, please refer to 1287.Xr ipsec 4 . 1288.It Li PF_KEY 1289Get or set various global information about the IPsec key management. 1290The third level name is the variable name. 1291The currently defined variable and names are: 1292.Bl -column "blockacq_lifetime" "integer" "yes" -offset indent 1293.It Sy Variable name Type Changeable 1294.It debug integer yes 1295.It spi_try integer yes 1296.It spi_min_value integer yes 1297.It spi_max_value integer yes 1298.It random_int integer yes 1299.It larval_lifetime integer yes 1300.It blockacq_count integer yes 1301.It blockacq_lifetime integer yes 1302.It esp_keymin integer yes 1303.It esp_auth integer yes 1304.It ah_keymin integer yes 1305.El 1306The variables are as follows: 1307.Bl -tag -width "123456" 1308.It Li debug 1309Turn on debugging message from within the kernel. 1310The value is a bitmap, as defined in 1311.Pa /usr/include/netkey/key_debug.h . 1312.It Li spi_try 1313The number of times the kernel will try to obtain an unique SPI 1314when it generates it from random number generator. 1315.It Li spi_min_value 1316Minimum SPI value when generating it within the kernel. 1317.It Li spi_max_value 1318Maximum SPI value when generating it within the kernel. 1319.It Li random_int 1320Interval to stir pseudo-random number generator, in seconds. 1321Pseudo-random number generator is used only as a last resort when 1322random number source 1323.Pq Pa /dev/urandom 1324is not available. 1325It should not really be used, and if it were used, 1326kernel will warn about it. 1327.It Li larval_lifetime 1328Lifetime for LARVAL SAD entries, in seconds. 1329.It Li blockacq_count 1330Number of ACQUIRE PF_KEY messages to be blocked after an ACQUIRE message. 1331It avoids flood of ACQUIRE PF_KEY from being sent from the kernel to the 1332key management daemon. 1333.It Li blockacq_lifetime 1334Lifetime of ACQUIRE PF_KEY message. 1335.It Li esp_keymin 1336Minimum ESP key length, in bits. 1337The value is used when the kernel creates proposal payload 1338on ACQUIRE PF_KEY message. 1339.It Li esp_auth 1340Whether ESP authentication should be used or not. 1341Non-zero value indicates that ESP authentication should be used. 1342The value is used when the kernel creates proposal payload 1343on ACQUIRE PF_KEY message. 1344.It Li ah_keymin 1345Minimum AH key length, in bits, 1346The value is used when the kernel creates proposal payload 1347on ACQUIRE PF_KEY message. 1348.El 1349.El 1350.Sh CTL_PROC 1351The string and integer information available for the CTL_PROC 1352is detailed below. 1353The changeable column shows whether a process with appropriate 1354privilege may change the value. 1355These values are per-process, 1356and as such may change from one process to another. 1357When a process is created, 1358the default values are inherited from its parent. 1359When a set-user-ID or set-group-ID binary is executed, the 1360value of PROC_PID_CORENAME is reset to the system default value. 1361The second level name is either the magic value PROC_CURPROC, which 1362points to the current process, or the PID of the target process. 1363.Bl -column "USER_COLL_WEIGHTS_MAXXXX" "integerXXX" "yes" -offset indent 1364.It Sy Third level name Type Changeable 1365.It PROC\_PID\_CORENAME string yes 1366.It PROC\_STOPEXEC int yes 1367.It PROC\_STOPFORK int yes 1368.It PROC\_PID\_LIMIT node not applicable 1369.El 1370.Bl -tag -width "123456" 1371.Pp 1372.It Li PROC_PID_CORENAME 1373The template used for the core dump file name (see 1374.Xr core 5 1375for details). 1376The base name must either be 1377.Nm core 1378or end with the suffix ``.core'' (the super-user may set arbitrary names). 1379By default it points to KERN_DEFCORENAME. 1380.It Li PROC_PID_LIMIT 1381Return resources limits, as defined for the 1382.Xr getrlimit 2 1383and 1384.Xr setrlimit 2 1385system calls. 1386The fourth level name is one of: 1387.Bl -tag -width PROC_PID_LIMIT_MEMLOCKAA 1388.It Li PROC_PID_LIMIT_CPU 1389The maximum amount of cpu time (in seconds) to be used by each process. 1390.It Li PROC_PID_LIMIT_FSIZE 1391The largest size (in bytes) file that may be created. 1392.It Li PROC_PID_LIMIT_DATA 1393The maximum size (in bytes) of the data segment for a process; 1394this defines how far a program may extend its break with the 1395.Xr sbrk 2 1396system call. 1397.It Li PROC_PID_LIMIT_STACK 1398The maximum size (in bytes) of the stack segment for a process; 1399this defines how far a program's stack segment may be extended. 1400Stack extension is performed automatically by the system. 1401.It Li PROC_PID_LIMIT_CORE 1402The largest size (in bytes) 1403.Pa core 1404file that may be created. 1405.It Li PROC_PID_LIMIT_RSS 1406The maximum size (in bytes) to which a process's resident set size may 1407grow. 1408This imposes a limit on the amount of physical memory to be given to 1409a process; if memory is tight, the system will prefer to take memory 1410from processes that are exceeding their declared resident set size. 1411.It Li PROC_PID_LIMIT_MEMLOCK 1412The maximum size (in bytes) which a process may lock into memory 1413using the 1414.Xr mlock 2 1415function. 1416.It Li PROC_PID_LIMIT_NPROC 1417The maximum number of simultaneous processes for this user id. 1418.It Li PROC_PID_LIMIT_NOFILE 1419The maximum number of open files for this process. 1420.El 1421.Pp 1422The fifth level name is one of PROC_PID_LIMIT_TYPE_SOFT or 1423PROC_PID_LIMIT_TYPE_HARD, to select respectively the soft or hard limit. 1424Both are of type integer. 1425.It Li PROC_STOPEXEC 1426If non zero, the process will be stopped on next 1427.Xr exec 3 1428call. 1429The process created by 1430.Xr exec 3 1431is created in the SSTOP state and is never scheduled for running 1432before being stopped. 1433This feature helps attaching a process with a debugger such as 1434.Xr gdb 1 1435before it had the opportunity to actually do anything. 1436.Pp 1437This value is inherited by the process's children. 1438.It Li PROC_STOPFORK 1439If non zero, the process' children will be stopped after 1440.Xr fork 2 1441calls. 1442The children is created in the SSTOP state and is never scheduled 1443for running before being stopped. 1444This feature helps attaching a process with a debugger such as 1445.Xr gdb 1 1446before it had the opportunity to actually do anything. 1447.Pp 1448This value is inherited by the process's children, and it also 1449apply to emulation specific system calls that fork a new process, such as 1450.Fn sproc 1451or 1452.Fn clone . 1453.El 1454.Sh CTL_USER 1455The string and integer information available for the CTL_USER level 1456is detailed below. 1457The changeable column shows whether a process with appropriate 1458privilege may change the value. 1459.Bl -column "USER_COLL_WEIGHTS_MAXXXX" "integerXXX" -offset indent 1460.It Sy Second level name Type Changeable 1461.It USER\_BC\_BASE\_MAX integer no 1462.It USER\_BC\_DIM\_MAX integer no 1463.It USER\_BC\_SCALE\_MAX integer no 1464.It USER\_BC\_STRING\_MAX integer no 1465.It USER\_COLL\_WEIGHTS\_MAX integer no 1466.It USER\_CS\_PATH string no 1467.It USER\_EXPR\_NEST\_MAX integer no 1468.It USER\_LINE\_MAX integer no 1469.It USER\_POSIX2\_CHAR\_TERM integer no 1470.It USER\_POSIX2\_C\_BIND integer no 1471.It USER\_POSIX2\_C\_DEV integer no 1472.It USER\_POSIX2\_FORT\_DEV integer no 1473.It USER\_POSIX2\_FORT\_RUN integer no 1474.It USER\_POSIX2\_LOCALEDEF integer no 1475.It USER\_POSIX2\_SW\_DEV integer no 1476.It USER\_POSIX2\_UPE integer no 1477.It USER\_POSIX2\_VERSION integer no 1478.It USER\_RE\_DUP\_MAX integer no 1479.It USER\_STREAM\_MAX integer no 1480.It USER\_TZNAME\_MAX integer no 1481.It USER\_ATEXIT\_MAX integer no 1482.El 1483.Bl -tag -width "123456" 1484.Pp 1485.It Li USER_BC_BASE_MAX 1486The maximum ibase/obase values in the 1487.Xr bc 1 1488utility. 1489.It Li USER_BC_DIM_MAX 1490The maximum array size in the 1491.Xr bc 1 1492utility. 1493.It Li USER_BC_SCALE_MAX 1494The maximum scale value in the 1495.Xr bc 1 1496utility. 1497.It Li USER_BC_STRING_MAX 1498The maximum string length in the 1499.Xr bc 1 1500utility. 1501.It Li USER_COLL_WEIGHTS_MAX 1502The maximum number of weights that can be assigned to any entry of 1503the LC_COLLATE order keyword in the locale definition file. 1504.It Li USER_CS_PATH 1505Return a value for the 1506.Ev PATH 1507environment variable that finds all the standard utilities. 1508.It Li USER_EXPR_NEST_MAX 1509The maximum number of expressions that can be nested within 1510parenthesis by the 1511.Xr expr 1 1512utility. 1513.It Li USER_LINE_MAX 1514The maximum length in bytes of a text-processing utility's input 1515line. 1516.It Li USER_POSIX2_CHAR_TERM 1517Return 1 if the system supports at least one terminal type capable of 1518all operations described in POSIX 1003.2, otherwise 0. 1519.It Li USER_POSIX2_C_BIND 1520Return 1 if the system's C-language development facilities support the 1521C-Language Bindings Option, otherwise 0. 1522.It Li USER_POSIX2_C_DEV 1523Return 1 if the system supports the C-Language Development Utilities Option, 1524otherwise 0. 1525.It Li USER_POSIX2_FORT_DEV 1526Return 1 if the system supports the FORTRAN Development Utilities Option, 1527otherwise 0. 1528.It Li USER_POSIX2_FORT_RUN 1529Return 1 if the system supports the FORTRAN Runtime Utilities Option, 1530otherwise 0. 1531.It Li USER_POSIX2_LOCALEDEF 1532Return 1 if the system supports the creation of locales, otherwise 0. 1533.It Li USER_POSIX2_SW_DEV 1534Return 1 if the system supports the Software Development Utilities Option, 1535otherwise 0. 1536.It Li USER_POSIX2_UPE 1537Return 1 if the system supports the User Portability Utilities Option, 1538otherwise 0. 1539.It Li USER_POSIX2_VERSION 1540The version of POSIX 1003.2 with which the system attempts to comply. 1541.It Li USER_RE_DUP_MAX 1542The maximum number of repeated occurrences of a regular expression 1543permitted when using interval notation. 1544.ne 1i 1545.It Li USER_STREAM_MAX 1546The minimum maximum number of streams that a process may have open 1547at any one time. 1548.It Li USER_TZNAME_MAX 1549The minimum maximum number of types supported for the name of a 1550timezone. 1551.It Li USER_ATEXIT_MAX 1552The maximum namber of functions that may be registered with 1553.Xr atexit 3 . 1554.El 1555.Sh CTL_VM 1556The string and integer information available for the CTL_VM level 1557is detailed below. 1558The changeable column shows whether a process with appropriate 1559privilege may change the value. 1560.Bl -column "Second level nameXXXXXX" "struct loadavgXXX" -offset indent 1561.It Sy Second level name Type Changeable 1562.It VM\_ANONMAX int yes 1563.It VM\_ANONMIN int yes 1564.It VM\_EXECMAX int yes 1565.It VM\_EXECMIN int yes 1566.It VM\_FILEMAX int yes 1567.It VM\_FILEMIN int yes 1568.It VM\_LOADAVG struct loadavg no 1569.It VM\_MAXSLP int no 1570.It VM\_METER struct vmtotal no 1571.It VM\_NKMEMPAGES int no 1572.It VM\_USPACE int no 1573.It VM\_UVMEXP struct uvmexp no 1574.It VM\_UVMEXP2 struct uvmexp_sysctl no 1575.El 1576.Pp 1577.Bl -tag -width "123456" 1578.It Li VM_ANONMAX 1579The percentage of physical memory which will be reclaimed 1580from other types of memory usage to store anonymous application data. 1581.It Li VM_ANONMIN 1582The percentage of physical memory which will be always be available for 1583anonymous application data. 1584.It Li VM_EXECMAX 1585The percentage of physical memory which will be reclaimed 1586from other types of memory usage to store cached executable data. 1587.It Li VM_EXECMIN 1588The percentage of physical memory which will be always be available for 1589cached executable data. 1590.It Li VM_FILEMAX 1591The percentage of physical memory which will be reclaimed 1592from other types of memory usage to store cached file data. 1593.It Li VM_FILEMIN 1594The percentage of physical memory which will be always be available for 1595cached file data. 1596.It Li VM_LOADAVG 1597Return the load average history. 1598The returned data consists of a 1599.Va struct loadavg . 1600.It Li VM_MAXSLP 1601The value of the maxslp kernel global variable. 1602.It Li VM_METER 1603Return system wide virtual memory statistics. 1604The returned data consists of a 1605.Va struct vmtotal . 1606.It Li VM_USPACE 1607The number of bytes allocated for each kernel stack. 1608.It Li VM_UVMEXP 1609Return system wide virtual memory statistics. 1610The returned data consists of a 1611.Va struct uvmexp . 1612.It Li VM_UVMEXP2 1613Return system wide virtual memory statistics. 1614The returned data consists of a 1615.Va struct uvmexp_sysctl . 1616.El 1617.Sh CTL_DDB 1618The integer information available for the CTL_DDB level is detailed below. 1619The changeable column shows whether a process with appropriate 1620privilege may change the value. 1621.Bl -column "DBCTL_TABSTOPSXXX" "integerXXX" -offset indent 1622.It Sy Second level name Type Changeable 1623.It DBCTL\_RADIX integer yes 1624.It DBCTL\_MAXOFF integer yes 1625.It DBCTL\_LINES integer yes 1626.It DBCTL\_TABSTOPS integer yes 1627.It DBCTL\_ONPANIC integer yes 1628.It DBCTL\_FROMCONSOLE integer yes 1629.El 1630.Pp 1631.Bl -tag -width "123456" 1632.It Li DBCTL_RADIX 1633The input and output radix. 1634.It Li DBCTL_MAXOFF 1635The maximum symbol offset. 1636.It Li DBCTL_LINES 1637Number of display lines. 1638.It Li DBCTL_TABSTOPS 1639Tab width. 1640.It Li DBCTL_ONPANIC 1641If non-zero, DDB will be entered when the kernel panics. 1642.It Li DBCTL_FROMCONSOLE 1643If not zero, DDB may be entered by sending a break on a serial 1644console or by a special key sequence on a graphics console. 1645.El 1646.Pp 1647These MIB nodes are also available as variables from within the DDB. 1648See 1649.Xr ddb 4 1650for more details. 1651.Sh CTL_VENDOR 1652The "vendor" toplevel name is reserved to be used by vendors who wish to 1653have their own private MIB tree. 1654Intended use is to store values under 1655.Dq vendor.\*[Lt]yourname\*[Gt].* . 1656.Sh RETURN VALUES 1657If the call to 1658.Nm 1659is successful, the number of bytes copied out is returned. 1660Otherwise \-1 is returned and 1661.Va errno 1662is set appropriately. 1663.Sh FILES 1664.Bl -tag -width \*[Lt]netinet6/udp6Xvar.h\*[Gt] -compact 1665.It Aq Pa sys/sysctl.h 1666definitions for top level identifiers, second level kernel and hardware 1667identifiers, and user level identifiers 1668.It Aq Pa sys/socket.h 1669definitions for second level network identifiers 1670.It Aq Pa sys/gmon.h 1671definitions for third level profiling identifiers 1672.It Aq Pa uvm/uvm_param.h 1673definitions for second level virtual memory identifiers 1674.It Aq Pa netinet/in.h 1675definitions for third level IPv4/v6 identifiers and 1676fourth level IPv4/v6 identifiers 1677.It Aq Pa netinet/icmp_var.h 1678definitions for fourth level ICMP identifiers 1679.It Aq Pa netinet/icmp6.h 1680definitions for fourth level ICMPv6 identifiers 1681.It Aq Pa netinet/tcp_var.h 1682definitions for fourth level TCP identifiers 1683.It Aq Pa netinet/udp_var.h 1684definitions for fourth level UDP identifiers 1685.It Aq Pa netinet6/udp6_var.h 1686definitions for fourth level IPv6 UDP identifiers 1687.It Aq Pa netinet6/ipsec.h 1688definitions for fourth level IPsec identifiers 1689.It Aq Pa netkey/key_var.h 1690definitions for third level PF_KEY identifiers 1691.El 1692.Sh ERRORS 1693The following errors may be reported: 1694.Bl -tag -width Er 1695.It Bq Er EFAULT 1696The buffer 1697.Fa name , 1698.Fa oldp , 1699.Fa newp , 1700or length pointer 1701.Fa oldlenp 1702contains an invalid address. 1703.It Bq Er EINVAL 1704The 1705.Fa name 1706array is less than two or greater than CTL_MAXNAME. 1707.It Bq Er EINVAL 1708A non-null 1709.Fa newp 1710is given and its specified length in 1711.Fa newlen 1712is too large or too small. 1713.It Bq Er ENOMEM 1714The length pointed to by 1715.Fa oldlenp 1716is too short to hold the requested value. 1717.It Bq Er ENOTDIR 1718The 1719.Fa name 1720array specifies an intermediate rather than terminal name. 1721.It Bq Er EOPNOTSUPP 1722The 1723.Fa name 1724array specifies a value that is unknown. 1725.It Bq Er EPERM 1726An attempt is made to set a read-only value. 1727.It Bq Er EPERM 1728A process without appropriate privilege attempts to set a value. 1729.It Bq Er EPERM 1730An attempt to change a value protected by the current kernel security 1731level is made. 1732.El 1733.Sh SEE ALSO 1734.Xr ipsec 4 , 1735.Xr sysctl 8 1736.Sh HISTORY 1737The 1738.Nm 1739function first appeared in 1740.Bx 4.4 . 1741