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);
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 auxilliary data. The buffer passed to and from a netlink socket
should be only accessed using these macros.
NLMSG_ALIGN
Round the length of a netlink message up to align it
properly.
NLMSG_LENGTH
Gets the payload length as argument and returns the
aligned length to store in the nlmsg_len field of the
nlmsghdr.
NLMSG_SPACE
Return the number of bytes a netlink message with payload
of the passed length 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 length parameter 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.
It is often better to use netlink via libnetlink than via the
low level kernel interface.
netlink(7)
and ftp://ftp.inr.ac.ru/ip-routing/iproute2* for libnetlink
Linux Man Page 1999-05-14 NETLINK(3)
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