NAME | SYNOPSIS | DESCRIPTION | BUGS | AUTHORS | SEE ALSO | COLOPHON

libnetlink(3)             Library Functions Manual             libnetlink(3)

NAME         top

       libnetlink - A library for accessing the netlink service

SYNOPSIS         top

       #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 rtnl_ctrl_data *,
                           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         top

       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.

       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. If there is a 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,
              anscillary data, the message itself, and the jarg cookie as
              arguments. It will get called for all received messages.  Only
              one message bundle is received. If there is a 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 should contain 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         top

       This library is meant for internal use, use libmnl for new programs.

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

AUTHORS         top

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

SEE ALSO         top

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

COLOPHON         top

       This page is part of the iproute2 (utilities for controlling TCP/IP
       networking and traffic) project.  Information about the project can
       be found at 
       ⟨http://www.linuxfoundation.org/collaborate/workgroups/networking/iproute2⟩.
       If you have a bug report for this manual page, send it to
       netdev@vger.kernel.org, shemminger@osdl.org.  This page was obtained
       from the project's upstream Git repository 
       ⟨git://git.kernel.org/pub/scm/linux/kernel/git/shemminger/iproute2.git⟩
       on 2017-03-13.  If you discover any rendering problems in this HTML
       version of the page, or you believe there is a better or more up-to-
       date source for the page, or you have corrections or improvements to
       the information in this COLOPHON (which is not part of the original
       manual page), send a mail to man-pages@man7.org

                                                               libnetlink(3)