NETLINK(3) Linux Programmers Manual NETLINK(3)
NAME
netlink - Netlink macros
SYNOPSIS
#include
#include
int NLMSG_ALIGN(size_t len);
int NLMSG_LENGTH(size_t len);
int NLMSG_SPACE(size_t len);
void *NLMSG_DATA(struct nlmsghdr *nlh);
struct nlmsghdr *NLMSG_NEXT(struct nlmsghdr *nlh, int len);
int NLMSG_OK(struct nlmsghdr *nlh, int len);
int NLMSG_PAYLOAD(struct nlmsghdr *nlh, int len);
DESCRIPTION
defines several standard macros to access or create a
netlink datagram. They are similar in spirit to the macros defined in
cmsg(3) for auxiliary data. The buffer passed to and from a netlink
socket should only be accessed using these macros.
NLMSG_ALIGN()
Round the length of a netlink message up to align it properly.
NLMSG_LENGTH()
Given the payload length, len, this macro returns the aligned
length to store in the nlmsg_len field of the nlmsghdr.
NLMSG_SPACE()
Return the number of bytes that a netlink message with payload
of len would occupy.
NLMSG_DATA()
Return a pointer to the payload associated with the passed nlms
ghdr.
NLMSG_NEXT()
Get the next nlmsghdr in a multipart message. The caller must
check if the current nlmsghdr didnt have the NLMSG_DONE set
this function doesnt return NULL on end. The len argument is
an lvalue containing the remaining length of the message buffer.
This macro decrements it by the length of the message header.
NLMSG_OK()
Return true if the netlink message is not truncated and ok to
parse.
NLMSG_PAYLOAD()
Return the length of the payload associated with the nlmsghdr.
CONFORMING TO
These macros are non-standard Linux extensions.
NOTES
It is often better to use netlink via libnetlink than via the low-level
kernel interface.
SEE ALSO
netlink(7)
and ftp://ftp.inr.ac.ru/ip-routing/iproute2* for libnetlink
COLOPHON
This page is part of release 3.05 of the Linux man-pages project. A
description of the project, and information about reporting bugs, can
be found at http://www.kernel.org/doc/man-pages/.
GNU 1999-05-14 NETLINK(3)
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