.\" A few small grammar fixes
.\" 2010-06-13 Jan Engelhardt <jengelh@medozas.de>
.\" Documented SO_DOMAIN and SO_PROTOCOL.
+.\"
.\" FIXME
.\" The following are not yet documented:
-.\" SO_PEERNAME (2.4?)
-.\" get only
-.\" Seems to do something similar to getpeernam(), but then
-.\" why is it necessary / how does it differ?
-.\" SO_TIMESTAMPNS (2.6.22)
-.\" Documentation/networking/timestamping.txt
-.\" commit 92f37fd2ee805aa77925c1e64fd56088b46094fc
-.\" Author: Eric Dumazet <dada1@cosmosbay.com>
-.\" SO_TIMESTAMPING (2.6.30)
-.\" Documentation/networking/timestamping.txt
-.\" commit cb9eff097831007afb30d64373f29d99825d0068
-.\" Author: Patrick Ohly <patrick.ohly@intel.com>
-.\" SO_RXQ_OVFL (2.6.33)
-.\" commit 3b885787ea4112eaa80945999ea0901bf742707f
-.\" Author: Neil Horman <nhorman@tuxdriver.com>
-.\" SO_WIFI_STATUS (3.3)
-.\" commit 6e3e939f3b1bf8534b32ad09ff199d88800835a0
-.\" Author: Johannes Berg <johannes.berg@intel.com>
-.\" Also: SCM_WIFI_STATUS
-.\" SO_NOFCS (3.4)
-.\" commit 3bdc0eba0b8b47797f4a76e377dd8360f317450f
-.\" Author: Ben Greear <greearb@candelatech.com>
-.\" SO_GET_FILTER (3.8)
-.\" commit a8fc92778080c845eaadc369a0ecf5699a03bef0
-.\" Author: Pavel Emelyanov <xemul@parallels.com>
-.\" SO_REUSEPORT (3.9)
-.\" commit c617f398edd4db2b8567a28e899a88f8f574798d
-.\" https://lwn.net/Articles/542629/
-.\" SO_LOCK_FILTER (3.9)
-.\" commit d59577b6ffd313d0ab3be39cb1ab47e29bdc9182
-.\" Author: Vincent Bernat <bernat@luffy.cx>
-.\" SO_SELECT_ERR_QUEUE (3.10)
-.\" commit 7d4c04fc170087119727119074e72445f2bb192b
-.\" Author: Keller, Jacob E <jacob.e.keller@intel.com>
-.\" SO_MAX_PACING_RATE (3.13)
-.\" commit 62748f32d501f5d3712a7c372bbb92abc7c62bc7
.\"
-.TH SOCKET 7 2014-01-20 Linux "Linux Programmer's Manual"
+.\" SO_PEERNAME (2.4?)
+.\" get only
+.\" Seems to do something similar to getpeername(), but then
+.\" why is it necessary / how does it differ?
+.\"
+.\" SO_TIMESTAMPNS (2.6.22)
+.\" Documentation/networking/timestamping.txt
+.\" commit 92f37fd2ee805aa77925c1e64fd56088b46094fc
+.\" Author: Eric Dumazet <dada1@cosmosbay.com>
+.\"
+.\" SO_TIMESTAMPING (2.6.30)
+.\" Documentation/networking/timestamping.txt
+.\" commit cb9eff097831007afb30d64373f29d99825d0068
+.\" Author: Patrick Ohly <patrick.ohly@intel.com>
+.\"
+.\" SO_WIFI_STATUS (3.3)
+.\" commit 6e3e939f3b1bf8534b32ad09ff199d88800835a0
+.\" Author: Johannes Berg <johannes.berg@intel.com>
+.\" Also: SCM_WIFI_STATUS
+.\"
+.\" SO_NOFCS (3.4)
+.\" commit 3bdc0eba0b8b47797f4a76e377dd8360f317450f
+.\" Author: Ben Greear <greearb@candelatech.com>
+.\"
+.\" SO_GET_FILTER (3.8)
+.\" commit a8fc92778080c845eaadc369a0ecf5699a03bef0
+.\" Author: Pavel Emelyanov <xemul@parallels.com>
+.\"
+.\" SO_SELECT_ERR_QUEUE (3.10)
+.\" commit 7d4c04fc170087119727119074e72445f2bb192b
+.\" Author: Keller, Jacob E <jacob.e.keller@intel.com>
+.\"
+.\" SO_MAX_PACING_RATE (3.13)
+.\" commit 62748f32d501f5d3712a7c372bbb92abc7c62bc7
+.\" Author: Eric Dumazet <edumazet@google.com>
+.\"
+.\" SO_BPF_EXTENSIONS (3.14)
+.\" commit ea02f9411d9faa3553ed09ce0ec9f00ceae9885e
+.\" Author: Michal Sekletar <msekleta@redhat.com>
+.\"
+.TH SOCKET 7 2019-03-06 Linux "Linux Programmer's Manual"
.SH NAME
socket \- Linux socket interface
.SH SYNOPSIS
.B #include <sys/socket.h>
-.sp
+.PP
.IB sockfd " = socket(int " socket_family ", int " socket_type ", int " protocol );
.SH DESCRIPTION
This manual page describes the Linux networking socket layer user
The protocol modules are grouped into
.I protocol families
such as
-.BR AF_INET ", " AF_IPX ", " AF_PACKET
+.BR AF_INET ", " AF_IPX ", and " AF_PACKET ,
and
.I socket types
such as
These functions are used by the user process to send or receive packets
and to do other socket operations.
For more information see their respective manual pages.
-
+.PP
.BR socket (2)
creates a socket,
.BR connect (2)
Socket has enough send buffer space for writing new data.
T}
Read/Write:T{
-POLLIN|
+POLLIN |
.br
POLLOUT
T}:T{
.BR getpeername (2)),
which are generic to all socket domains,
to determine the domain of a particular socket address.
-
+.PP
To allow any type of socket address to be passed to
interfaces in the sockets API,
the type
domain-specific socket address types to a "generic" type,
so as to avoid compiler warnings about type mismatches in
calls to the sockets API.
-
+.PP
In addition, the sockets API provides the data type
.IR "struct sockaddr_storage".
This type
IPv6 socket addresses.)
The structure includes the following field, which can be used to identify
the type of socket address actually stored in the structure:
-
+.PP
.in +4n
-.nf
+.EX
sa_family_t ss_family;
-.fi
+.EE
.in
-
+.PP
The
.I sockaddr_storage
structure is useful in programs that must handle socket addresses
.I optval
is a pointer to an
.IR int .
-.\" FIXME
+.\" FIXME .
.\" In the list below, the text used to describe argument types
.\" for each socket option should be more consistent
.\"
the value 1 indicates that this is a listening socket.
This socket option is read-only.
.TP
+.BR SO_ATTACH_FILTER " (since Linux 2.2), " SO_ATTACH_BPF " (since Linux 3.19)"
+Attach a classic BPF
+.RB ( SO_ATTACH_FILTER )
+or an extended BPF
+.RB ( SO_ATTACH_BPF )
+program to the socket for use as a filter of incoming packets.
+A packet will be dropped if the filter program returns zero.
+If the filter program returns a
+nonzero value which is less than the packet's data length,
+the packet will be truncated to the length returned.
+If the value returned by the filter is greater than or equal to the
+packet's data length, the packet is allowed to proceed unmodified.
+.IP
+The argument for
+.BR SO_ATTACH_FILTER
+is a
+.I sock_fprog
+structure, defined in
+.IR <linux/filter.h> :
+.IP
+.in +4n
+.EX
+struct sock_fprog {
+ unsigned short len;
+ struct sock_filter *filter;
+};
+.EE
+.in
+.IP
+The argument for
+.BR SO_ATTACH_BPF
+is a file descriptor returned by the
+.BR bpf (2)
+system call and must refer to a program of type
+.BR BPF_PROG_TYPE_SOCKET_FILTER .
+.IP
+These options may be set multiple times for a given socket,
+each time replacing the previous filter program.
+The classic and extended versions may be called on the same socket,
+but the previous filter will always be replaced such that a socket
+never has more than one filter defined.
+.IP
+Both classic and extended BPF are explained in the kernel source file
+.I Documentation/networking/filter.txt
+.TP
+.BR SO_ATTACH_REUSEPORT_CBPF ", " SO_ATTACH_REUSEPORT_EBPF
+For use with the
+.BR SO_REUSEPORT
+option, these options allow the user to set a classic BPF
+.RB ( SO_ATTACH_REUSEPORT_CBPF )
+or an extended BPF
+.RB ( SO_ATTACH_REUSEPORT_EBPF )
+program which defines how packets are assigned to
+the sockets in the reuseport group (that is, all sockets which have
+.BR SO_REUSEPORT
+set and are using the same local address to receive packets).
+.IP
+The BPF program must return an index between 0 and N\-1 representing
+the socket which should receive the packet
+(where N is the number of sockets in the group).
+If the BPF program returns an invalid index,
+socket selection will fall back to the plain
+.BR SO_REUSEPORT
+mechanism.
+.IP
+Sockets are numbered in the order in which they are added to the group
+(that is, the order of
+.BR bind (2)
+calls for UDP sockets or the order of
+.BR listen (2)
+calls for TCP sockets).
+New sockets added to a reuseport group will inherit the BPF program.
+When a socket is removed from a reuseport group (via
+.BR close (2)),
+the last socket in the group will be moved into the closed socket's
+position.
+.IP
+These options may be set repeatedly at any time on any socket in the group
+to replace the current BPF program used by all sockets in the group.
+.IP
+.BR SO_ATTACH_REUSEPORT_CBPF
+takes the same argument type as
+.BR SO_ATTACH_FILTER
+and
+.BR SO_ATTACH_REUSEPORT_EBPF
+takes the same argument type as
+.BR SO_ATTACH_BPF .
+.IP
+UDP support for this feature is available since Linux 4.5;
+TCP support is available since Linux 4.6.
+.TP
.B SO_BINDTODEVICE
Bind this socket to a particular device like \(lqeth0\(rq,
as specified in the passed interface name.
It is not supported for packet sockets (use normal
.BR bind (2)
there).
-
+.IP
Before Linux 3.8,
this socket option could be set, but could not retrieved with
.BR getsockopt (2).
.I optlen
argument should contain the buffer size available
to receive the device name and is recommended to be
-.BR IFNAMSZ
+.BR IFNAMSIZ
bytes.
The real device name length is reported back in the
.I optlen
.B SO_BSDCOMPAT
Enable BSD bug-to-bug compatibility.
This is used by the UDP protocol module in Linux 2.0 and 2.2.
-If enabled ICMP errors received for a UDP socket will not be passed
+If enabled, ICMP errors received for a UDP socket will not be passed
to the user program.
In later kernel versions, support for this option has been phased out:
Linux 2.4 silently ignores it, and Linux 2.6 generates a kernel warning
.TP
.B SO_DEBUG
Enable socket debugging.
-Only allowed for processes with the
+Allowed only for processes with the
.B CAP_NET_ADMIN
capability or an effective user ID of 0.
.TP
+.BR SO_DETACH_FILTER " (since Linux 2.2), " SO_DETACH_BPF " (since Linux 3.19)"
+These two options, which are synonyms,
+may be used to remove the classic or extended BPF
+program attached to a socket with either
+.BR SO_ATTACH_FILTER
+or
+.BR SO_ATTACH_BPF .
+The option value is ignored.
+.TP
.BR SO_DOMAIN " (since Linux 2.6.32)"
Retrieves the socket domain as an integer, returning a value such as
.BR AF_INET6 .
operation.
Expects an integer boolean flag.
.TP
+.BR SO_INCOMING_CPU " (gettable since Linux 3.19, settable since Linux 4.4)"
+.\" getsockopt 2c8c56e15df3d4c2af3d656e44feb18789f75837
+.\" setsockopt 70da268b569d32a9fddeea85dc18043de9d89f89
+Sets or gets the CPU affinity of a socket.
+Expects an integer flag.
+.IP
+.in +4n
+.EX
+int cpu = 1;
+setsockopt(fd, SOL_SOCKET, SO_INCOMING_CPU, &cpu, sizeof(cpu));
+.EE
+.in
+.IP
+Because all of the packets for a single stream
+(i.e., all packets for the same 4-tuple)
+arrive on the single RX queue that is associated with a particular CPU,
+the typical use case is to employ one listening process per RX queue,
+with the incoming flow being handled by a listener
+on the same CPU that is handling the RX queue.
+This provides optimal NUMA behavior and keeps CPU caches hot.
+.\"
+.\" From an email conversation with Eric Dumazet:
+.\" >> Note that setting the option is not supported if SO_REUSEPORT is used.
+.\" >
+.\" > Please define "not supported". Does this yield an API diagnostic?
+.\" > If so, what is it?
+.\" >
+.\" >> Socket will be selected from an array, either by a hash or BPF program
+.\" >> that has no access to this information.
+.\" >
+.\" > Sorry -- I'm lost here. How does this comment relate to the proposed
+.\" > man page text above?
+.\"
+.\" Simply that :
+.\"
+.\" If an application uses both SO_INCOMING_CPU and SO_REUSEPORT, then
+.\" SO_REUSEPORT logic, selecting the socket to receive the packet, ignores
+.\" SO_INCOMING_CPU setting.
+.TP
.B SO_KEEPALIVE
Enable sending of keep-alive messages on connection-oriented sockets.
Expects an integer boolean flag.
The argument is a
.I linger
structure.
-.sp
+.IP
.in +4n
-.nf
+.EX
struct linger {
int l_onoff; /* linger active */
int l_linger; /* how many seconds to linger for */
};
-.fi
+.EE
.in
.IP
When enabled, a
.BR exit (2),
it always lingers in the background.
.TP
+.B SO_LOCK_FILTER
+.\" commit d59577b6ffd313d0ab3be39cb1ab47e29bdc9182
+When set, this option will prevent
+changing the filters associated with the socket.
+These filters include any set using the socket options
+.BR SO_ATTACH_FILTER ,
+.BR SO_ATTACH_BPF ,
+.BR SO_ATTACH_REUSEPORT_CBPF ,
+and
+.BR SO_ATTACH_REUSEPORT_EBPF .
+.IP
+The typical use case is for a privileged process to set up a raw socket
+(an operation that requires the
+.BR CAP_NET_RAW
+capability), apply a restrictive filter, set the
+.BR SO_LOCK_FILTER
+option,
+and then either drop its privileges or pass the socket file descriptor
+to an unprivileged process via a UNIX domain socket.
+.IP
+Once the
+.BR SO_LOCK_FILTER
+option has been enabled, attempts to change or remove the filter
+attached to a socket, or to disable the
+.BR SO_LOCK_FILTER
+option will fail with the error
+.BR EPERM .
+.TP
.BR SO_MARK " (since Linux 2.6.25)"
.\" commit 4a19ec5800fc3bb64e2d87c4d9fdd9e636086fe0
.\" and 914a9ab386a288d0f22252fc268ecbc048cdcbd5
.B SO_OOBINLINE
If this option is enabled,
out-of-band data is directly placed into the receive data stream.
-Otherwise out-of-band data is passed only when the
+Otherwise, out-of-band data is passed only when the
.B MSG_OOB
flag is set during receiving.
.\" don't document it because it can do too much harm.
.\".B SO_NO_CHECK
+.\" The kernel has support for the SO_NO_CHECK socket
+.\" option (boolean: 0 == default, calculate checksum on xmit,
+.\" 1 == do not calculate checksum on xmit).
+.\" Additional note from Andi Kleen on SO_NO_CHECK (2010-08-30)
+.\" On Linux UDP checksums are essentially free and there's no reason
+.\" to turn them off and it would disable another safety line.
+.\" That is why I didn't document the option.
.TP
.B SO_PASSCRED
Enable or disable the receiving of the
control message.
For more information see
.BR unix (7).
-.\" FIXME Document SO_PASSSEC, added in 2.6.18; there is some info
-.\" in the 2.6.18 ChangeLog
+.TP
+.B SO_PASSSEC
+Enable or disable the receiving of the
+.B SCM_SECURITY
+control message.
+For more information see
+.BR unix (7).
.TP
.BR SO_PEEK_OFF " (since Linux 3.4)"
.\" commit ef64a54f6e558155b4f149bb10666b9e914b6c54
This option, which is currently supported only for
.BR unix (7)
sockets, sets the value of the "peek offset" for the
-.BR recv(2)
+.BR recv (2)
system call when used with
.BR MSG_PEEK
flag.
-
+.IP
When this option is set to a negative value
(it is set to \-1 for all new sockets),
traditional behavior is provided:
-.BR recv(2)
+.BR recv (2)
with the
.BR MSG_PEEK
flag will peek data from the front of the queue.
-
+.IP
When the option is set to a value greater than or equal to zero,
then the next peek at data queued in the socket will occur at
the byte offset specified by the option value.
At the same time, the "peek offset" will be
incremented by the number of bytes that were peeked from the queue,
so that a subsequent peek will return the next data in the queue.
-
+.IP
If data is removed from the front of the queue via a call to
.BR recv (2)
(or similar) without the
the correct relative position in the queued data,
so that a subsequent peek will retrieve the data that would have been
retrieved had the data not been removed.
-
+.IP
For datagram sockets, if the "peek offset" points to the middle of a packet,
the data returned will be marked with the
.BR MSG_TRUNC
flag.
-
+.IP
The following example serves to illustrate the use of
.BR SO_PEEK_OFF .
Suppose a stream socket has the following queued input data:
-
+.IP
aabbccddeeff
-
.IP
The following sequence of
.BR recv (2)
calls would have the effect noted in the comments:
-
+.IP
.in +4n
-.nf
+.EX
int ov = 4; // Set peek offset to 4
setsockopt(fd, SOL_SOCKET, SO_PEEK_OFF, &ov, sizeof(ov));
recv(fd, buf, 2, MSG_PEEK); // Peeks "dd"; offset set to 8
recv(fd, buf, 2, 0); // Reads "aa"; offset set to 6
recv(fd, buf, 2, MSG_PEEK); // Peeks "ee"; offset set to 8
-.fi
+.EE
.in
.TP
.B SO_PEERCRED
-Return the credentials of the foreign process connected to this socket.
-This is possible only for connected
-.B AF_UNIX
-stream sockets and
-.B AF_UNIX
-stream and datagram socket pairs created using
-.BR socketpair (2);
-see
+Return the credentials of the peer process connected to this socket.
+For further details, see
.BR unix (7).
-The returned credentials are those that were in effect at the time
-of the call to
-.BR connect (2)
-or
-.BR socketpair (2).
-The argument is a
-.I ucred
-structure; define the
-.B GNU_SOURCE
-feature test macro to obtain the definition of that structure from
-.IR <sys/socket.h> .
-This socket option is read-only.
.TP
.B SO_PRIORITY
Set the protocol-defined priority for all packets to be sent on
Linux uses this value to order the networking queues:
packets with a higher priority may be processed first depending
on the selected device queueing discipline.
-For
-.BR ip (7),
-this also sets the IP type-of-service (TOS) field for outgoing packets.
+.\" For
+.\" .BR ip (7),
+.\" this also sets the IP type-of-service (TOS) field for outgoing packets.
Setting a priority outside the range 0 to 6 requires the
.B CAP_NET_ADMIN
capability.
and this doubled value is returned by
.BR getsockopt (2).
.\" The following thread on LMKL is quite informative:
-.\" getsockopt/setsockopt with SO_RCVBUF and SO_SNDBUF "non-standard" behaviour
+.\" getsockopt/setsockopt with SO_RCVBUF and SO_SNDBUF "non-standard" behavior
.\" 17 July 2012
.\" http://thread.gmane.org/gmane.linux.kernel/1328935
The default value is set by the
.B SO_RCVLOWAT
is changeable
only since Linux 2.4.
-The
-.BR select (2)
+.IP
+Before Linux 2.6.28
+.\" commit c7004482e8dcb7c3c72666395cfa98a216a4fb70
+.BR select (2),
+.BR poll (2),
and
-.BR poll (2)
-system calls currently do not respect the
+.BR epoll (7)
+did not respect the
.B SO_RCVLOWAT
setting on Linux,
-and mark a socket readable when even a single byte of data is available.
-A subsequent read from the socket will block until
+and indicated a socket as readable when even a single byte of data
+was available.
+A subsequent read from the socket would then block until
.B SO_RCVLOWAT
bytes are available.
.\" See http://marc.theaimsgroup.com/?l=linux-kernel&m=111049368106984&w=2
If an input or output function blocks for this period of time, and
data has been sent or received, the return value of that function
will be the amount of data transferred; if no data has been transferred
-and the timeout has been reached then \-1 is returned with
+and the timeout has been reached, then \-1 is returned with
.I errno
set to
.BR EAGAIN
(for
.BR connect (2))
just as if the socket was specified to be nonblocking.
-If the timeout is set to zero (the default)
+If the timeout is set to zero (the default),
then the operation will never timeout.
Timeouts only have effect for system calls that perform socket I/O (e.g.,
.BR read (2),
and so on.
.TP
.B SO_REUSEADDR
+.\" commit c617f398edd4db2b8567a28e899a88f8f574798d
+.\" https://lwn.net/Articles/542629/
Indicates that the rules used in validating addresses supplied in a
.BR bind (2)
call should allow reuse of local addresses.
to bind to this port for any local address.
Argument is an integer boolean flag.
.TP
+.BR SO_REUSEPORT " (since Linux 3.9)"
+Permits multiple
+.B AF_INET
+or
+.B AF_INET6
+sockets to be bound to an identical socket address.
+This option must be set on each socket (including the first socket)
+prior to calling
+.BR bind (2)
+on the socket.
+To prevent port hijacking,
+all of the processes binding to the same address must have the same
+effective UID.
+This option can be employed with both TCP and UDP sockets.
+.IP
+For TCP sockets, this option allows
+.BR accept (2)
+load distribution in a multi-threaded server to be improved by
+using a distinct listener socket for each thread.
+This provides improved load distribution as compared
+to traditional techniques such using a single
+.BR accept (2)ing
+thread that distributes connections,
+or having multiple threads that compete to
+.BR accept (2)
+from the same socket.
+.IP
+For UDP sockets,
+the use of this option can provide better distribution
+of incoming datagrams to multiple processes (or threads) as compared
+to the traditional technique of having multiple processes
+compete to receive datagrams on the same socket.
+.TP
+.BR SO_RXQ_OVFL " (since Linux 2.6.33)"
+.\" commit 3b885787ea4112eaa80945999ea0901bf742707f
+Indicates that an unsigned 32-bit value ancillary message (cmsg)
+should be attached to received skbs indicating
+the number of packets dropped by the socket since its creation.
+.TP
.B SO_SNDBUF
Sets or gets the maximum socket send buffer in bytes.
The kernel doubles this value (to allow space for bookkeeping overhead)
.BR SOCK_STREAM ).
This socket option is read-only.
.TP
-.B SO_BUSY_POLL
+.BR SO_BUSY_POLL " (since Linux 3.11)"
Sets the approximate time in microseconds to busy poll on a blocking receive
when there is no data.
Increasing this value requires
The default for this option is controlled by the
.I /proc/sys/net/core/busy_read
file.
-
+.IP
The value in the
.I /proc/sys/net/core/busy_poll
file determines how long
will busy poll when they operate on sockets with
.BR SO_BUSY_POLL
set and no events to report are found.
-
+.IP
In both cases,
busy polling will only be done when the socket last received data
from a network device that supports this option.
-
+.IP
While busy polling may improve latency of some applications,
care must be taken when using it since this will increase
both CPU utilization and power usage.
.SS Ioctls
These operations can be accessed using
.BR ioctl (2):
-
+.PP
.in +4n
-.nf
+.EX
.IB error " = ioctl(" ip_socket ", " ioctl_type ", " &value_result ");"
-.fi
+.EE
.in
.TP
.B SIOCGSTAMP
.BR ENOENT ).
.TP
.B SIOCSPGRP
-Set the process or process group to send
+Set the process or process group that is to receive
.B SIGIO
or
.B SIGURG
-signals
-to when an
-asynchronous I/O operation has finished or urgent data is available.
+signals when I/O becomes possible or urgent data is available.
The argument is a pointer to a
.IR pid_t .
-If the argument is positive, send the signals to that process.
-If the
-argument is negative, send the signals to the process group with the ID
-of the absolute value of the argument.
-The process may only choose itself or its own process group to receive
-signals unless it has the
-.B CAP_KILL
-capability or an effective UID of 0.
+For further details, see the description of
+.BR F_SETOWN
+in
+.BR fcntl (2).
.TP
.B FIOASYNC
Change the
is new in Linux 2.2.
The
.I /proc
-interfaces was introduced in Linux 2.2.
+interfaces were introduced in Linux 2.2.
.B SO_RCVTIMEO
and
.B SO_SNDTIMEO
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 reuse with the
+.PP
+Linux will allow port reuse only with the
.B SO_REUSEADDR
option
when this option was set both in the previous program that performed a
option.
Typically this difference is invisible, since, for example, a server
program is designed to always set this option.
-.SH BUGS
-The
-.B CONFIG_FILTER
-socket options
-.B SO_ATTACH_FILTER
-and
-.B SO_DETACH_FILTER
-.\" FIXME Document SO_ATTACH_FILTER and SO_DETACH_FILTER
-are not documented.
-The suggested interface to use them is via the libpcap
-library.
.\" .SH AUTHORS
.\" This man page was written by Andi Kleen.
.SH SEE ALSO
-.BR getsockopt (2),
+.BR wireshark (1),
+.BR bpf (2),
.BR connect (2),
+.BR getsockopt (2),
.BR setsockopt (2),
.BR socket (2),
+.BR pcap (3),
+.BR address_families (7),
.BR capabilities (7),
.BR ddp (7),
.BR ip (7),
.BR packet (7),
.BR tcp (7),
.BR udp (7),
-.BR unix (7)
+.BR unix (7),
+.BR tcpdump (8)
projects / thirdparty / man-pages.git / blobdiff