connect.2, listen.2, send.2, uname.2, cmsg.3, proc.5, arp.7, ddp.7, icmp.7, ip.7, raw.7, socket.7, tcp.7, udp.7: Global fix: eliminate mention of the obsolete sysctl(2) interface

Many pages still mention use of the obsolete sysctl(2) system
call, or used the term "sysctls"; rewrite these mentions to
instead be in terms of /proc interfaces.

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

man2/connect.2

@@ -62,7 +62,7 @@
 .\" Modified 1998, 1999 by Andi Kleen
 .\" Modified 2004-06-23 by Michael Kerrisk <mtk.manpages@gmail.com>
 .\"
-.TH CONNECT 2 2008-08-08 "Linux" "Linux Programmer's Manual"
+.TH CONNECT 2 2008-11-20 "Linux" "Linux Programmer's Manual"
 .SH NAME
 connect \- initiate a connection on a socket
 .SH SYNOPSIS
@@ -156,11 +156,10 @@ field.
 No more free local ports or insufficient entries in the routing cache.
 For
 .B AF_INET
-see the
-.I net.ipv4.ip_local_port_range
-sysctl in
+see the description of
+.I /proc/sys/net/ipv4/ip_local_port_range
 .BR ip (7)
-on how to increase the number of local ports.
+for information on how to increase the number of local ports.
 .TP
 .B EALREADY
 The socket is non-blocking and a previous connection attempt has not yet

man2/listen.2

@@ -40,7 +40,7 @@
 .\" Modified 11 May 2001 by Sam Varshavchik <mrsam@courier-mta.com>
 .\"
 .\"
-.TH LISTEN 2 2007-12-28 "Linux" "Linux Programmer's Manual"
+.TH LISTEN 2 2008-11-20 "Linux" "Linux Programmer's Manual"
 .SH NAME
 listen \- listen for connections on a socket
 .SH SYNOPSIS
@@ -141,11 +141,10 @@ Now it specifies the queue length for
 established sockets waiting to be accepted,
 instead of the number of incomplete connection requests.
 The maximum length of the queue for incomplete sockets
-can be set using the
-.I tcp_max_syn_backlog
-sysctl.
+can be set using
+.IR /proc/sys/net/ipv4/tcp_max_syn_backlog .
 When syncookies are enabled there is no logical maximum
-length and this sysctl setting is ignored.
+length and this setting is ignored.
 See
 .BR tcp (7)
 for more information.

man2/send.2

@@ -35,7 +35,7 @@
 .\" Modified Oct 2003 by aeb
 .\" Modified 2004-07-01 by mtk
 .\"
-.TH SEND 2 2008-10-06 "Linux" "Linux Programmer's Manual"
+.TH SEND 2 2008-11-20 "Linux" "Linux Programmer's Manual"
 .SH NAME
 send, sendto, sendmsg \- send a message on a socket
 .SH SYNOPSIS
@@ -255,9 +255,9 @@ and
 .I msg_controllen
 members.
 The maximum control buffer length the kernel can process is limited
-per socket by the
-.I net.core.optmem_max
-sysctl; see
+per socket by the value in
+.IR /proc/sys/net/core/optmem_max ;
+see
 .BR socket (7).
 .\" Still to be documented:
 .\"  Send file descriptors and user credentials using the

man2/uname.2

@@ -22,7 +22,7 @@
 .\"
 .\" 2007-07-05 mtk: Added details on underlying system call interfaces
 .\"
-.TH UNAME 2 2008-11-19 "Linux" "Linux Programmer's Manual"
+.TH UNAME 2 2008-11-20 "Linux" "Linux Programmer's Manual"
 .SH NAME
 uname \- get name and information about current kernel
 .SH SYNOPSIS
@@ -119,8 +119,6 @@ idea to use any of these constants; just use sizeof(...).
 Often 257 is chosen in order to have room for an internet hostname.
 .LP
 Part of the utsname information is also accessible via
-.BR sysctl (2)
-and via
 .IR /proc/sys/kernel/ { ostype ,
 .IR hostname ,
 .IR osrelease ,

man3/cmsg.3

@@ -4,7 +4,7 @@
 .\" and in case of nontrivial modification author and date
 .\" of the modification is added to the header.
 .\" $Id: cmsg.3,v 1.8 2000/12/20 18:10:31 ak Exp $
-.TH CMSG 3 1998-10-02 "Linux" "Linux Programmer's Manual"
+.TH CMSG 3 2008-11-20 "Linux" "Linux Programmer's Manual"
 .SH NAME
 CMSG_ALIGN, CMSG_SPACE, CMSG_NXTHDR, CMSG_FIRSTHDR \- Access ancillary data
 .SH SYNOPSIS
@@ -51,9 +51,9 @@ structures with appended data.
 This sequence should only be accessed
 using the macros described in this manual page and never directly.
 See the specific protocol man pages for the available control message types.
-The maximum ancillary buffer size allowed per socket can be set using the
-.I net.core.optmem_max
-sysctl; see
+The maximum ancillary buffer size allowed per socket can be set using
+.IR /proc/sys/net/core/optmem_max ;
+see
 .BR socket (7).
 .PP
 .BR CMSG_FIRSTHDR ()

man5/proc.5

@@ -1706,7 +1706,7 @@ See also
 This directory (present since 1.3.57) contains a number of files
 and subdirectories corresponding to kernel variables.
 These variables can be read and sometimes modified using
-the \fI/proc\fP file system, and the
+the \fI/proc\fP file system, and the (deprecated)
 .BR sysctl (2)
 system call.
 Presently, there are subdirectories

man7/arp.7

@@ -6,7 +6,7 @@
 .\" of the modification is added to the header.
 .\" Modified June 1999 Andi Kleen
 .\" $Id: arp.7,v 1.10 2000/04/27 19:31:38 ak Exp $
-.TH ARP 7 2008-08-08 "Linux" "Linux Programmer's Manual"
+.TH ARP 7 2008-11-20 "Linux" "Linux Programmer's Manual"
 .SH NAME
 arp \- Linux ARP kernel module.
 .SH DESCRIPTION
@@ -39,10 +39,14 @@ Entries which are marked
 as permanent are never deleted by the garbage-collector.
 The cache can
 be directly manipulated by the use of ioctls and its behavior can be
-tuned by the sysctls defined below.
+tuned by the
+.I /proc
+interfaces described below.
 
 When there is no positive feedback for an existing mapping after some
-time (see the sysctls below) a neighbor cache entry is considered stale.
+time (see the 
+.I /proc
+interfaces below) a neighbor cache entry is considered stale.
 Positive feedback can be gotten from a higher layer; for example from
 a successful TCP ACK.
 Other protocols can signal forward progress
@@ -128,19 +132,18 @@ Linux 2.2 does not support proxy network ARP entries, so this
 should be set to 0xffffffff, or 0 to remove an existing proxy arp entry.
 .B ATF_USETRAILERS
 is obsolete and should not be used.
-.SS Sysctls
-ARP supports a sysctl interface to configure parameters on a global
-or per-interface basis.
-The sysctls can be accessed by reading or writing the
+.SS /proc interfaces
+ARP supports a range of
+.I /proc
+interfaces to configure parameters on a global or per-interface basis.
+The interfaces can be accessed by reading or writing the
 .I /proc/sys/net/ipv4/neigh/*/*
-files or with the
-.BR sysctl (2)
-interface.
+files.
 Each interface in the system has its own directory in
-/proc/sys/net/ipv4/neigh/.
+.IR /proc/sys/net/ipv4/neigh/ .
 The setting in the "default" directory is used for all newly created
 devices.
-Unless otherwise specified time-related sysctls are specified
+Unless otherwise specified time-related interfaces are specified
 in seconds.
 .TP
 .I anycast_delay
@@ -249,7 +252,7 @@ forwarding and proxy arp is enabled for the interface).
 
 The
 .I neigh/*
-sysctls did not exist before Linux 2.2.
+interfaces did not exist before Linux 2.2.
 .SH BUGS
 Some timer settings are specified in jiffies, which is architecture-
 and kernel version-dependent; see

man7/ddp.7

@@ -4,7 +4,7 @@
 .\" and in case of nontrivial modification author and date
 .\" of the modification is added to the header.
 .\" $Id: ddp.7,v 1.3 1999/05/13 11:33:22 freitag Exp $
-.TH DDP  7 2008-08-08 "Linux" "Linux Programmer's Manual"
+.TH DDP  7 2008-11-20 "Linux" "Linux Programmer's Manual"
 .SH NAME
 ddp \- Linux AppleTalk protocol implementation
 .SH SYNOPSIS
@@ -114,14 +114,12 @@ local broadcast address.
 .\" FIXME this doesn't make sense [johnl]
 .SS "Socket Options"
 No protocol-specific socket options are supported.
-.SS Sysctls
-IP supports a sysctl interface to configure some global AppleTalk
-parameters.
-The sysctls can be accessed by reading or writing the
-.I /proc/sys/net/atalk/*
-files or with the
-.BR sysctl (2)
-interface.
+.SS /proc interfaces
+IP supports a set of
+.I /proc
+interfaces to configure some global AppleTalk parameters.
+The parameters can be accessed by reading or writing files in the directory
+.IR /proc/sys/net/atalk/ .
 .TP
 .I aarp-expiry-time
 The time interval (in seconds) before an AARP cache entry expires.
@@ -141,7 +139,7 @@ changed.
 .SS Ioctls
 All ioctls described in
 .BR socket (7)
-apply to ddp.
+apply to DDP.
 .\" FIXME Add a section about multicasting
 .SH ERRORS
 .\" FIXME document all errors. We should really fix the kernels to
@@ -218,9 +216,8 @@ The socket was unconfigured, or an unknown socket type was requested.
 .SH VERSIONS
 Appletalk is supported by Linux 2.0 or higher.
 The
-.B sysctl
-interface is
-new in Linux 2.2.
+.I /proc
+interfaces exist since Linux 2.2.
 .SH NOTES
 Be very careful with the
 .B SO_BROADCAST

man7/icmp.7

@@ -4,7 +4,7 @@
 .\" and in case of nontrivial modification author and date
 .\" of the modification is added to the header.
 .\" $Id: icmp.7,v 1.6 2000/08/14 08:03:45 ak Exp $
-.TH ICMP 7 1999-04-27 "Linux" "Linux Programmer's Manual"
+.TH ICMP 7 2008-11-20 "Linux" "Linux Programmer's Manual"
 .SH NAME
 icmp, IPPROTO_ICMP \- Linux IPv4 ICMP kernel module.
 .SH DESCRIPTION
@@ -33,14 +33,13 @@ Linux limits the rate of ICMP error packets to each destination.
 and
 .B ICMP_DEST_UNREACH
 are also limited by the destination route of the incoming packets.
-.SS Sysctls
-ICMP supports a sysctl interface to configure some global IP parameters.
-The sysctls can be accessed by reading or writing the
-.I /proc/sys/net/ipv4/*
-files or with the
-.BR sysctl (2)
-interface.
-Most of these sysctls are rate limitations for specific ICMP types.
+.SS /proc interfaces
+ICMP supports a set of
+.I /proc
+interfaces to configure some global IP parameters.
+The parameters can be accessed by reading or writing files in the directory
+.IR /proc/sys/net/ipv4/ .
+Most of these parameters are rate limitations for specific ICMP types.
 Linux 2.2 uses a token bucket filter to limit ICMPs.
 .\" FIXME better description needed
 The value is the timeout in jiffies until the token bucket filter is

man7/ip.7

@@ -228,7 +228,8 @@ is established.
 The processing of all incoming source routing options
 is disabled by default and can be enabled by using the
 .I accept_source_route
-sysctl.
+.I /proc
+interface.
 Other options like timestamps are still handled.
 For datagram sockets, IP options can be only set by the local user.
 Calling
@@ -519,8 +520,8 @@ as defined in RFC\ 1191
 on this socket.
 The don't fragment flag is set on all outgoing datagrams.
 The system-wide default is controlled by the
-.I ip_no_pmtu_disc
-sysctl for
+.I /proc/sys/net/ipv4/ip_no_pmtu_disc
+file for
 .B SOCK_STREAM
 sockets, and disabled on all others.
 For
@@ -700,18 +701,17 @@ structure similar to
 When an invalid socket option is passed,
 .B ENOPROTOOPT
 is returned.
-.SS Sysctls
+.SS /proc interfaces
 The IP protocol
-supports the sysctl interface to configure some global options.
-The sysctls can be accessed by reading or writing the
-.I /proc/sys/net/ipv4/*
-files or using the
+supports a set of
+.I /proc
+interfaces to configure some global parameters.
+The parameters can be accessed by reading or writing files in the directory
+.IR /proc/sys/net/ipv4/ .
 .\" FIXME As at 2.6.12, 14 Jun 2005, the following are undocumented:
 .\"	ip_queue_maxlen
 .\"	ip_conntrack_max
-.BR sysctl (2)
-interface.
-Variables described as
+Interfaces described as
 .I Boolean
 take an integer value, with a non-zero value ("true") meaning that
 the corresponding option is enabled, and a zero value ("false")
@@ -818,8 +818,8 @@ bytes.
 .I neigh/*
 See
 .BR arp (7).
-.\" FIXME Document the conf/*/* sysctls
-.\" FIXME Document the route/* sysctls
+.\" FIXME Document the conf/*/* interfaces
+.\" FIXME Document the route/* interfaces
 .\" FIXME document them all
 .SS Ioctls
 All ioctls described in
@@ -952,7 +952,9 @@ is new in Linux 2.2.
 Linux 2.0 only supported
 .BR ip_mreq .
 .PP
-The sysctls were introduced with Linux 2.2.
+The
+.I /proc
+interfaces were introduced with Linux 2.2.
 .SH NOTES
 Be very careful with the
 .B SO_BROADCAST

man7/raw.7

@@ -6,7 +6,7 @@
 .\" and in case of nontrivial modification author and date
 .\" of the modification is added to the header.
 .\" $Id: raw.7,v 1.6 1999/06/05 10:32:08 freitag Exp $
-.TH RAW  7 2008-08-08 "Linux" "Linux Programmer's Manual"
+.TH RAW  7 2008-11-20 "Linux" "Linux Programmer's Manual"
 .SH NAME
 raw, SOCK_RAW \- Linux IPv4 raw sockets
 .SH SYNOPSIS
@@ -190,8 +190,8 @@ When this happens the application should decrease the packet size.
 Path MTU discovery can be also turned off using the
 .B IP_MTU_DISCOVER
 socket option or the
-.I ip_no_pmtu_disc
-sysctl, see
+.I /proc/sys/net/ipv4/ip_no_pmtu_disc
+file, see
 .BR ip (7)
 for details.
 When turned off raw sockets will fragment outgoing packets

man7/socket.7

@@ -14,7 +14,7 @@
 .\"     Added notes on capability requirements
 .\"	A few small grammar fixes
 .\"
-.TH SOCKET 7 2008-08-08 Linux "Linux Programmer's Manual"
+.TH SOCKET 7 2008-11-20 Linux "Linux Programmer's Manual"
 .SH NAME
 socket \- Linux socket interface
 .SH SYNOPSIS
@@ -364,10 +364,10 @@ when it is set using
 and this doubled value is returned by
 .BR getsockopt (2).
 The default value is set by the
-.I rmem_default
-sysctl and the maximum allowed value is set by the
-.I rmem_max
-sysctl.
+.I /proc/sys/net/core/rmem_default
+file, and the maximum allowed value is set by the
+.I /proc/sys/net/core/rmem_max
+file.
 The minimum (doubled) value for this option is 256.
 .TP
 .BR SO_RCVBUFFORCE " (since Linux 2.6.14)"
@@ -463,10 +463,10 @@ when it is set using
 and this doubled value is returned by
 .BR getsockopt (2).
 The default value is set by the
-.I wmem_default
-sysctl and the maximum allowed value is set by the
-.I wmem_max
-sysctl.
+.I /proc/sys/net/core/wmem_default
+file and the maximum allowed value is set by the
+.I /proc/sys/net/core/wmem_max
+file.
 The minimum (doubled) value for this option is 2048.
 .TP
 .BR SO_SNDBUFFORCE " (since Linux 2.6.14)"
@@ -544,12 +544,10 @@ may have already disappeared when the process reacts to the signal.
 If this happens, the process should wait again because Linux
 will resend the signal later.
 .\" .SS Ancillary Messages
-.SS Sysctls
-The core socket networking sysctls can be accessed using the
-.I /proc/sys/net/core/*
-files or with the
-.BR sysctl (2)
-interface.
+.SS /proc interfaces
+The core socket networking parameters can be accessed
+via files in the directory
+.IR /proc/sys/net/core/ .
 .TP
 .I rmem_default
 contains the default setting in bytes of the socket receive buffer.
@@ -678,7 +676,9 @@ The same as the
 was introduced in Linux 2.0.30.
 .B SO_PASSCRED
 is new in Linux 2.2.
-The sysctls are new in Linux 2.2.
+The
+.I /proc
+interfaces was introduced in Linux 2.2.
 .B SO_RCVTIMEO
 and
 .B SO_SNDTIMEO
@@ -687,8 +687,9 @@ Earlier, timeouts were fixed to
 a protocol-specific setting, and could not be read or written.
 .SH NOTES
 Linux assumes that half of the send/receive buffer is used for internal
-kernel structures; thus the sysctls are twice what can be observed
-on the wire.
+kernel structures; thus the values in the corresponding
+.I /proc
+files are twice what can be observed on the wire.
 
 Linux will only allow port re-use with the
 .B SO_REUSEADDR

man7/tcp.7

@@ -12,7 +12,7 @@
 .\" 	  documented: tcp_mtu_probing, tcp_base_mss, and
 .\"	  tcp_workaround_signed_windows
 .\"
-.TH TCP  7 2008-08-08 "Linux" "Linux Programmer's Manual"
+.TH TCP  7 2008-11-20 "Linux" "Linux Programmer's Manual"
 .SH NAME
 tcp \- TCP protocol
 .SH SYNOPSIS
@@ -71,10 +71,10 @@ latency or bandwidth.
 To make use of them, the send and
 receive buffer sizes must be increased.
 They can be set globally with the
-.I net.ipv4.tcp_wmem
+.I /proc/sys/net/ipv4/tcp_wmem
 and
-.I net.ipv4.tcp_rmem
-sysctl variables, or on individual sockets by using the
+.I /proc/sys/net/ipv4/tcp_rmem
+files, or on individual sockets by using the
 .B SO_SNDBUF
 and
 .B SO_RCVBUF
@@ -86,11 +86,11 @@ The maximum sizes for socket buffers declared via the
 .B SO_SNDBUF
 and
 .B SO_RCVBUF
-mechanisms are limited by the global
-.I net.core.rmem_max
+mechanisms are limited by the values in the
+.I /proc/sys/net/core/rmem_max
 and
-.I net.core.wmem_max
-sysctls.
+.I /proc/sys/net/core/wmem_max
+files.
 Note that TCP actually allocates twice the size of
 the buffer requested in the
 .BR setsockopt (2)
@@ -101,7 +101,9 @@ in the
 .BR setsockopt (2)
 call.
 TCP uses the extra space for administrative purposes and internal
-kernel structures, and the sysctl variables reflect the
+kernel structures, and the
+/proc
+file values reflect the
 larger sizes compared to the actual TCP windows.
 On individual connections, the socket buffer size must be
 set prior to the
@@ -161,13 +163,12 @@ apply to TCP.
 TCP only supports point-to-point
 communication; broadcasting and multicasting are not
 supported.
-.SS Sysctls
-These variables can be accessed by the
-.I /proc/sys/net/ipv4/*
-files or with the
-.BR sysctl (2)
-interface.
-In addition, most IP sysctls also apply to TCP; see
+.SS /proc interfaces
+System-wide TCP parameter settings can be accessed by files in the directory
+.IR /proc/sys/net/ipv4/ .
+In addition, most IP
+.I /proc
+interfaces also apply to TCP; see
 .BR ip (7).
 Variables described as
 .I Boolean
@@ -444,7 +445,7 @@ These parameters are used by TCP to regulate receive
 buffer sizes.
 TCP dynamically adjusts the size of the
 receive buffer from the defaults listed below, in the range
-of these sysctl variables, depending on memory available
+of these values, depending on memory available
 in the system.
 .RS
 .TP 9
@@ -606,8 +607,8 @@ TCP Reno in wired networks and throughput over wireless links.
 This is a vector of 3 integers: [min, default, max].
 These parameters are used by TCP to regulate send buffer sizes.
 TCP dynamically adjusts the size of the send buffer from the
-default values listed below, in the range of these sysctl
-variables, depending on memory available.
+default values listed below, in the range of these values,
+depending on memory available.
 
 .I min
 - minimum size of the send buffer used by each TCP socket.
@@ -629,15 +630,15 @@ defined for all protocols.
 The default value is 16K bytes.
 If larger send buffer sizes are desired, this value
 should be increased (to affect all sockets).
-To employ large TCP windows, the sysctl variable
-.I net.ipv4.tcp_window_scaling
-must be enabled (default).
+To employ large TCP windows, the 
+.I /proc/sys/net/ipv4/tcp_window_scaling
+must be set to a non-zero value (default).
 
 .I max
 - the maximum size of the send buffer used by
 each TCP socket.
-This value does not override the global
-.IR net.core.wmem_max .
+This value does not override the value in
+.IR /proc/sys/net/core/wmem_max .
 This is not used to limit the size of the send buffer
 declared using
 .B SO_SNDBUF
@@ -715,9 +716,9 @@ portable.
 .TP
 .B TCP_LINGER2
 The lifetime of orphaned FIN_WAIT2 state sockets.
-This option can be used to override the system wide sysctl
-.I tcp_fin_timeout
-on this socket.
+This option can be used to override the system-wide setting in the file
+.I /proc/sys/net/ipv4/tcp_fin_timeout
+for this socket.
 This is not to be confused with the
 .BR socket (7)
 level option
@@ -882,11 +883,13 @@ Support for Explicit Congestion Notification, zero-copy
 reordering support and some SACK extensions
 (DSACK) were introduced in 2.4.
 Support for forward acknowledgement (FACK), TIME_WAIT recycling,
-per connection keepalive socket options and sysctls
-were introduced in 2.3.
+per connection keepalive socket options and the
+.I /proc
+interfaces were introduced in 2.3.
 
-The default values and descriptions for the sysctl variables
-given above are applicable for the 2.4 kernel.
+The default values and descriptions for the
+.I /proc
+files given above are applicable for the 2.4 kernel.
 .SH NOTES
 TCP has no real out-of-band data; it has urgent data.
 In Linux this means if the other end sends newer out-of-band
@@ -900,9 +903,8 @@ Linux uses the BSD compatible interpretation of the urgent
 pointer field by default.
 This violates RFC\ 1122, but is
 required for interoperability with other stacks.
-It can be changed by the
-.I tcp_stdurg
-sysctl.
+It can be changed via
+.IR /proc/sys/net/ipv4/tcp_stdurg .
 .SH BUGS
 Not all errors are documented.
 .br
@@ -925,7 +927,6 @@ IPv6 is not described.
 .BR sendfile (2),
 .BR sendmsg (2),
 .BR socket (2),
-.BR sysctl (2),
 .BR ip (7),
 .BR socket (7)
 .sp

man7/udp.7

@@ -5,7 +5,7 @@
 .\" of the modification is added to the header.
 .\" $Id: udp.7,v 1.7 2000/01/22 01:55:05 freitag Exp $
 .\"
-.TH UDP  7 2008-08-08 "Linux" "Linux Programmer's Manual"
+.TH UDP  7 2008-11-20 "Linux" "Linux Programmer's Manual"
 .SH NAME
 udp \- User Datagram Protocol for IPv4
 .SH SYNOPSIS
@@ -60,7 +60,9 @@ is not supported.
 
 IP options may be sent or received using the socket options described in
 .BR ip (7).
-They are only processed by the kernel when the appropriate sysctl
+They are only processed by the kernel when the appropriate
+/proc
+parameter
 is enabled (but still passed to the user even when it is turned off).
 See
 .BR ip (7).
@@ -79,8 +81,8 @@ When this happens the application should decrease the packet size.
 Path MTU discovery can be also turned off using the
 .B IP_MTU_DISCOVER
 socket option or the
-.I ip_no_pmtu_disc
-sysctl, see
+.I /proc/sys/net/ipv4/ip_no_pmtu_disc
+file; see
 .BR ip (7)
 for details.
 When turned off UDP will fragment outgoing UDP packets