1NETLINK(3)                 Linux Programmer's Manual                NETLINK(3)
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NAME

6       netlink - Netlink macros
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SYNOPSIS

9       #include <asm/types.h>
10       #include <linux/netlink.h>
11       int NLMSG_ALIGN(size_t len);
12       int NLMSG_LENGTH(size_t len);
13       int NLMSG_SPACE(size_t len);
14       void *NLMSG_DATA(struct nlmsghdr *nlh);
15       struct nlmsghdr *NLMSG_NEXT(struct nlmsghdr *nlh, int len);
16       int NLMSG_OK(struct nlmsghdr *nlh, int len);
17       int NLMSG_PAYLOAD(struct nlmsghdr *nlh, int len);
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DESCRIPTION

20       <linux/netlink.h> defines several standard macros to access or create a
21       netlink datagram.  They are similar in spirit to the macros defined  in
22       cmsg(3)  for  auxiliary  data.  The buffer passed to and from a netlink
23       socket should be only accessed using these macros.
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26       NLMSG_ALIGN
27              Round the length of a netlink  message  up  to  align  it
28              properly.
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30       NLMSG_LENGTH
31              Gets  the  payload  length  as  argument  and returns the
32              aligned length to store in the  nlmsg_len  field  of  the
33              nlmsghdr.
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36       NLMSG_SPACE
37              Return the number of bytes a netlink message with payload
38              of the passed length would occupy.
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40       NLMSG_DATA
41              Return a pointer  to  the  payload  associated  with  the
42              passed nlmsghdr.
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44       NLMSG_NEXT
45              Get the next nlmsghdr in a multipart message.  The caller
46              must check  if  the  current  nlmsghdr  didn't  have  the
47              NLMSG_DONE  set  —  this  function doesn't return NULL on
48              end.  The length parameter is an  lvalue  containing  the
49              remaining  length  of  the  message  buffer.   This macro
50              decrements it by the length of the message header.
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52       NLMSG_OK
53              Return true if the netlink message is not  truncated  and
54              ok to parse.
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56       NLMSG_PAYLOAD
57              Return  the  length  of  the  payload associated with the
58              nlmsghdr.
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NOTES

62       It is often better to use netlink via libnetlink  than  via  the
63       low level kernel interface.
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SEE ALSO

67       netlink(7)
68
69       and ftp://ftp.inr.ac.ru/ip-routing/iproute2* for libnetlink
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73Linux Man Page                    1999-05-14                        NETLINK(3)
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