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| -rw-r--r-- | man3/netlink.3 | 87 |
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diff --git a/man3/netlink.3 b/man3/netlink.3 new file mode 100644 index 0000000..eeb8875 --- /dev/null +++ b/man3/netlink.3 @@ -0,0 +1,87 @@ +.\" This manpage copyright 1998 by Andi Kleen. +.\" +.\" SPDX-License-Identifier: GPL-1.0-or-later +.\" +.\" Based on the original comments from Alexey Kuznetsov +.\" $Id: netlink.3,v 1.1 1999/05/14 17:17:24 freitag Exp $ +.\" +.TH netlink 3 2023-03-30 "Linux man-pages 6.05.01" +.SH NAME +netlink \- Netlink macros +.SH LIBRARY +Standard C library +.RI ( libc ", " \-lc ) +.SH SYNOPSIS +.nf +.B #include <asm/types.h> +.B #include <linux/netlink.h> +.PP +.BI "int NLMSG_ALIGN(size_t " len ); +.BI "int NLMSG_LENGTH(size_t " len ); +.BI "int NLMSG_SPACE(size_t " len ); +.BI "void *NLMSG_DATA(struct nlmsghdr *" nlh ); +.BI "struct nlmsghdr *NLMSG_NEXT(struct nlmsghdr *" nlh ", int " len ); +.BI "int NLMSG_OK(struct nlmsghdr *" nlh ", int " len ); +.BI "int NLMSG_PAYLOAD(struct nlmsghdr *" nlh ", int " len ); +.fi +.SH DESCRIPTION +.I <linux/netlink.h> +defines several standard macros to access or create a netlink datagram. +They are similar in spirit to the macros defined in +.BR cmsg (3) +for auxiliary data. +The buffer passed to and from a netlink socket should +be accessed using only these macros. +.TP +.BR NLMSG_ALIGN () +Round the length of a netlink message up to align it properly. +.TP +.BR NLMSG_LENGTH () +Given the payload length, +.IR len , +this macro returns the aligned length to store in the +.I nlmsg_len +field of the +.IR nlmsghdr . +.TP +.BR NLMSG_SPACE () +Return the number of bytes that a netlink message with payload of +.I len +would occupy. +.TP +.BR NLMSG_DATA () +Return a pointer to the payload associated with the passed +.IR nlmsghdr . +.TP +.\" this is bizarre, maybe the interface should be fixed. +.BR NLMSG_NEXT () +Get the next +.I nlmsghdr +in a multipart message. +The caller must check if the current +.I nlmsghdr +didn't have the +.B NLMSG_DONE +set\[em]this function doesn't return NULL on end. +The +.I len +argument is an lvalue containing the remaining length +of the message buffer. +This macro decrements it by the length of the message header. +.TP +.BR NLMSG_OK () +Return true if the netlink message is not truncated and +is in a form suitable for parsing. +.TP +.BR NLMSG_PAYLOAD () +Return the length of the payload associated with the +.IR nlmsghdr . +.SH VERSIONS +It is often better to use netlink via +.I libnetlink +than via the low-level kernel interface. +.SH STANDARDS +Linux. +.SH SEE ALSO +.BR libnetlink (3), +.BR netlink (7) |