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
Round the length of a netlink message up to align it properly.
Given the payload length,
len, this macro returns the
aligned length to store in the
nlmsg_len field of the
Return the number of bytes that a netlink message with payload of
len would occupy.
Return a pointer to the payload associated with the passed
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
len argument is an lvalue containing the remaining
length of the message buffer. This macro decrements it by the length of
the message header.
Return true if the netlink message is not truncated and is in a form suitable for parsing.
Return the length of the payload associated with the
These macros are nonstandard Linux extensions.
It is often better to use netlink via
libnetlink than via
the low-level kernel interface.
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