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| author | Alejandro Colomar <alx@kernel.org> | 2025-11-25 00:32:05 +0100 |
|---|---|---|
| committer | Alejandro Colomar <alx@kernel.org> | 2025-11-25 01:10:35 +0100 |
| commit | 582fce4c02b32ecfc75351c3494cbf4f307f5b6b (patch) | |
| tree | 65621bce4517dfb0392efbeeb2bb68ac26a88c49 /man/man2const/IP_OPTIONS.2const | |
| parent | e11a82a6f7098b94bcd00fb767a1db269e3a83db (diff) | |
| parent | 869bbbf4705313f690e85ad09b9b300b9f846165 (diff) | |
| download | man-pages-master.tar.gz | |
Signed-off-by: Alejandro Colomar <alx@kernel.org>
Diffstat (limited to 'man/man2const/IP_OPTIONS.2const')
| -rw-r--r-- | man/man2const/IP_OPTIONS.2const | 71 |
1 files changed, 71 insertions, 0 deletions
diff --git a/man/man2const/IP_OPTIONS.2const b/man/man2const/IP_OPTIONS.2const new file mode 100644 index 0000000000..f60d5aece0 --- /dev/null +++ b/man/man2const/IP_OPTIONS.2const @@ -0,0 +1,71 @@ +.\" Copyright, the authors of the Linux man-pages project +.\" +.\" SPDX-License-Identifier: Linux-man-pages-copyleft +.\" +.TH IP_OPTIONS 2const (date) "Linux man-pages (unreleased)" +.SH NAME +IP_OPTIONS +\- +options to be sent with every packet +.SH LIBRARY +Standard C library +.RI ( libc ,\~ \-lc ) +.SH SYNOPSIS +.nf +.BR "#include <netinet/in.h>" " /* Definition of " IP* " constants */" +.B #include <sys/socket.h> +.P +.BI int\~setsockopt(int\~ sockfd ,\~IPPROTO_IP,\~IP_OPTIONS, +.BI " const\~void\~" buf [ size ],\~size_t\~ size ); +.BI int\~getsockopt(int\~ sockfd ,\~IPPROTO_IP,\~IP_OPTIONS, +.BI " void\~" buf [ size ],\~size_t\~ size ); +.fi +.SH DESCRIPTION +Set or get the IP options to be sent with every packet from this socket. +.P +The arguments are a pointer to a memory buffer containing the options +and the buffer length. +.P +The +.BR setsockopt (2) +call sets the IP options associated with a socket. +The maximum option size for IPv4 is 40 bytes. +See RFC\ 791 for the allowed options. +.P +When the initial connection request packet for a +.B SOCK_STREAM +socket contains IP options, +the IP options will be set automatically +to the options from the initial packet with routing headers reversed. +.P +Incoming packets are not allowed to change options +after the connection is established. +.P +The processing of all incoming source routing options +is disabled by default and can be enabled by using the +.I accept_source_route +.I /proc +interface. +Other options like timestamps are still handled. +.P +For datagram sockets, IP options can be set only by the local user. +.P +Calling +.BR getsockopt (2) +with +.B IP_OPTIONS +puts the current IP options used for sending into the supplied buffer. +.SH ERRORS +See +.BR IPPROTO_IP (2const). +See +.BR setsockopt (2). +See +.BR ip (7). +.SH HISTORY +Linux 2.0. +.\" Precisely: since Linux 1.3.30 +.SH SEE ALSO +.BR IPPROTO_IP (2const), +.BR setsockopt (2), +.BR ip (7) |