man/man3/libnetlink.3

#include <asm/types.h>
#include <libnetlink.h>
#include <linux/netlink.h>
#include <linux/rtnetlink.h>
int rtnl_open(struct rtnl_handle *rth, unsigned subscriptions)
int rtnl_wilddump_request(struct rtnl_handle *rth, int family, int type)
int rtnl_send(struct rtnl_handle *rth, char *buf, int len)
int rtnl_dump_request(struct rtnl_handle *rth, int type, void *req, int len)
int rtnl_dump_filter(struct rtnl_handle *rth,
 int (*filter)(struct sockaddr_nl *, struct nlmsghdr *n, void *),
 void *arg1,
 int (*junk)(struct sockaddr_nl *,struct nlmsghdr *n, void *),
 void *arg2)
int rtnl_talk(struct rtnl_handle *rtnl, struct nlmsghdr *n, pid_t peer,
 unsigned groups, struct nlmsghdr *answer,
 int (*junk)(struct sockaddr_nl *,struct nlmsghdr *n, void *),
 void *jarg)
int rtnl_listen(struct rtnl_handle *rtnl,
 int (*handler)(struct sockaddr_nl *,struct nlmsghdr *n, void *),
 void *jarg)
int rtnl_from_file(FILE *rtnl,
 int (*handler)(struct sockaddr_nl *,struct nlmsghdr *n, void *),
 void *jarg)
int addattr32(struct nlmsghdr *n, int maxlen, int type, __u32 data)
int addattr_l(struct nlmsghdr *n, int maxlen, int type, void *data, int alen)
int rta_addattr32(struct rtattr *rta, int maxlen, int type, __u32 data)
int rta_addattr_l(struct rtattr *rta, int maxlen, int type, void *data, int alen)
 DESCRIPTION
libnetlink provides a higher level interface to
 rtnetlink(7).  The read functions return 0 on success and a negative errno on failure.
The send functions return the amount of data sent, or -1 on error.

rtnl_open
Open a rtnetlink socket and save the state into the
 rth handle. This handle is passed to all subsequent calls.
 subscriptions is a bitmap of the rtnetlink multicast groups the socket will be
a member of.


rtnl_wilddump_request
Request a full dump of the
 type database for
 family addresses.
 type is a rtnetlink message type.
 XXX


rtnl_dump_request
Request a full dump of the
 type  data buffer into
 buf with maximum length of
 len.  type is a rtnetlink message type.


rtnl_dump_filter
Receive netlink data after a request and filter it.
The
 filter callback checks if the received message is wanted. It gets the source
address of the message, the message itself and
 arg1  as arguments. 0 as return means that the filter passed, a negative
value is returned
by
 rtnl_dump_filter  in case of error. NULL for
 filter means to not use a filter.
 junk is used to filter messages not destined to the local socket.
Only one message bundle is received. Unless there is no message
pending, this function does not block.


rtnl_listen
Receive netlink data after a request and pass it to
 handler.  handler is a callback that gets the message source address, the message itself,
and the
 jarg cookie as arguments. It will get called for all received messages.
Only one message bundle is received. Unless there is no message
pending this function does not block.


rtnl_from_file
Works like
 rtnl_listen,  but reads a netlink message bundle from the file
 file and passes the messages to
 handler for parsing. The file contains raw data as received from a rtnetlink socket.

The following functions are useful to construct custom rtnetlink messages. For
simple database dumping with filtering it is better to use the higher level
functions above. See
 rtnetlink(3) and
 netlink(3) on how to generate a rtnetlink message. The following utility functions
require a continuous buffer that already contains a netlink message header
and a rtnetlink request.


rtnl_send
Send the rtnetlink message in
 buf of length
 len to handle
 rth.

addattr32
Add a __u32 attribute of type
 type and with value
 data to netlink message
 n, which is part of a buffer of length
 maxlen.

addattr_l
Add a variable length attribute of type
 type and with value
 data and
 alen length to netlink message
 n, which is part of a buffer of length
 maxlen.  data  is copied.


rta_addattr32
Initialize the rtnetlink attribute
 rta with a __u32 data value.


rta_addattr32
Initialize the rtnetlink attribute
 rta with a variable length data value.

 BUGS
The functions sometimes use fprintf and exit when a fatal error occurs.
This library should be named librtnetlink.

 AUTHORS
netlink/rtnetlink was designed and written by Alexey Kuznetsov.
Andi Kleen wrote the man page.

 SEE ALSO
 netlink(7),  rtnetlink(7) /usr/include/linux/rtnetlink.h