Libnetstack

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Code lives at https://github.com/dankamongmen/libnetstack.

==rtnetlink==

<tt>rtnetlink(7)</tt> (originally implemented AFAIK by Alexey Kuznetsov, the Mad Russian, whom I haven't seen post to [[LKML]] in many years, and miss) provides the <tt>NETLINK_ROUTE</tt> protocol for the <tt>AF_NETLINK</tt> family of sockets. According to <tt>netlink(7)</tt>,<blockquote>Netlink is a datagram-oriented service. Both <tt>SOCK_RAW</tt> and <tt>SOCK_DGRAM</tt> are valid values for socket_type. However, the netlink protocol does not distinguish between datagram and raw sockets."—<tt>netlink(7)</tt>, Linux man pages 5.03</blockquote> Creating and using such a socket does not require any special permissions, though <tt>CAP_NET_ADMIN</tt> is needed for many control messages (verified kernel-side, of course). Once established, we can directly request dumps of networking stack state with the <tt>RTM_GET*</tt> set of messages, and/or simply subscribe to the appropriate multicast groups, sit back, and let new events roll to us.

{|class="wikitable"

! Group !! Messages

|-

| <tt>RTNLGRP_LINK</tt> || <tt>RTM_NEWLINK</tt>, <tt>RTM_DELLINK</tt>

|-

| <tt>RTNLGRP_IPV4_IFADDR</tt> || <tt>RTM_NEWADDR</tt>, <tt>RTM_DELADDR</tt> (AF_INET only)

|-

| <tt>RTNLGRP_IPV6_IFADDR</tt> || <tt>RTM_NEWADDR</tt>, <tt>RTM_DELADDR</tt> (AF_INET6 only)

|-

| <tt>RTNLGRP_IPV4_ROUTE</tt> || <tt>RTM_NEWROUTE</tt>, <tt>RTM_DELROUTE</tt> (AF_INET only)

|-

| <tt>RTNLGRP_IPV6_ROUTE</tt> || <tt>RTM_NEWROUTE</tt>, <tt>RTM_DELROUTE</tt> (AF_INET6 only)

|-

| <tt>RTNLGRP_NEIGH</tt> || <tt>RTM_NEWNEIGH</tt>, <tt>RTM_DELNEIGH</tt>

|-

|}

==See also==

* "[https://inai.de/documents/Netlink_Protocol.pdf The Netlink protocol: Mysteries Uncovered]", Jan Engelhardt 2010-10-30

[[CATEGORY: Projects]]

Libnetstack: Difference between revisions

Dank (talk | contribs)

@@ Line 2: / Line 2: @@
 Code lives at https://github.com/dankamongmen/libnetstack.
+==rtnetlink==
+<tt>rtnetlink(7)</tt> (originally implemented AFAIK by Alexey Kuznetsov, the Mad Russian, whom I haven't seen post to [[LKML]] in many years, and miss) provides the <tt>NETLINK_ROUTE</tt> protocol for the <tt>AF_NETLINK</tt> family of sockets. According to <tt>netlink(7)</tt>,<blockquote>Netlink  is  a datagram-oriented service. Both <tt>SOCK_RAW</tt> and <tt>SOCK_DGRAM</tt> are valid values for socket_type. However, the netlink  protocol  does not distinguish between datagram and raw sockets."—<tt>netlink(7)</tt>, Linux man pages 5.03</blockquote> Creating and using such a socket does not require any special permissions, though <tt>CAP_NET_ADMIN</tt> is needed for many control messages (verified kernel-side, of course). Once established, we can directly request dumps of networking stack state with the <tt>RTM_GET*</tt> set of messages, and/or simply subscribe to the appropriate multicast groups, sit back, and let new events roll to us.
+{|class="wikitable"
+! Group !! Messages
+|-
+| <tt>RTNLGRP_LINK</tt> || <tt>RTM_NEWLINK</tt>, <tt>RTM_DELLINK</tt>
+|-
+| <tt>RTNLGRP_IPV4_IFADDR</tt> || <tt>RTM_NEWADDR</tt>, <tt>RTM_DELADDR</tt> (AF_INET only)
+|-
+| <tt>RTNLGRP_IPV6_IFADDR</tt> || <tt>RTM_NEWADDR</tt>, <tt>RTM_DELADDR</tt> (AF_INET6 only)
+|-
+| <tt>RTNLGRP_IPV4_ROUTE</tt> || <tt>RTM_NEWROUTE</tt>, <tt>RTM_DELROUTE</tt> (AF_INET only)
+|-
+| <tt>RTNLGRP_IPV6_ROUTE</tt> || <tt>RTM_NEWROUTE</tt>, <tt>RTM_DELROUTE</tt> (AF_INET6 only)
+|-
+| <tt>RTNLGRP_NEIGH</tt> || <tt>RTM_NEWNEIGH</tt>, <tt>RTM_DELNEIGH</tt>
+|-
+|}
+{{#github:README.md|dankamongmen/libnetstack}}
+==See also==
+* "[https://inai.de/documents/Netlink_Protocol.pdf The Netlink protocol: Mysteries Uncovered]", Jan Engelhardt 2010-10-30
 [[CATEGORY: Projects]]