NETLINK(3) manual page
Table of Contents
netlink - Netlink macros
#include <asm/types.h>
#include <linux/netlink.h>
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);
<linux/netlink.h>
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 be accessed
using only 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 nlmsghdr.
- NLMSG_NEXT()
- Get the next nlmsghdr
in a multipart message. The caller must check if the current nlmsghdr didn’t
have the NLMSG_DONE set--this function doesn’t 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 is in a form suitable
for parsing.
- NLMSG_PAYLOAD()
- Return the length of the payload associated
with the nlmsghdr.
These macros are nonstandard Linux extensions.
It is often better to use netlink via libnetlink than via the low-level
kernel interface.
libnetlink(3)
, netlink(7)
This page is
part of release 3.78 of the Linux man-pages project. A description of the
project, information about reporting bugs, and the latest version of this
page, can be found at http://www.kernel.org/doc/man-pages/.
Table of Contents
![[Go to CFHT Home Page]](/images/cfht-icon.gif){kind=icon}
Man Pages 
Back to Software Index 
Manpage Top Level