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authorDaniel Borkmann <dborkman@redhat.com>2013-06-21 21:38:08 +0400
committerDavid S. Miller <davem@davemloft.net>2013-06-25 03:39:05 +0400
commite4fc408e0e99fd2e009c8b3702d9637f5554fd5c (patch)
treef808ee97e82aaeea7c5fce0dea7ae37610ad27cb /drivers/net/Kconfig
parentbcbde0d449eda7afa8f63280b165c8300dbd00e2 (diff)
downloadlinux-e4fc408e0e99fd2e009c8b3702d9637f5554fd5c.tar.xz
packet: nlmon: virtual netlink monitoring device for packet sockets
Currently, there is no good possibility to debug netlink traffic that is being exchanged between kernel and user space. Therefore, this patch implements a netlink virtual device, so that netlink messages will be made visible to PF_PACKET sockets. Once there was an approach with a similar idea [1], but it got forgotten somehow. I think it makes most sense to accept the "overhead" of an extra netlink net device over implementing the same functionality from PF_PACKET sockets once again into netlink sockets. We have BPF filters that can already be easily applied which even have netlink extensions, we have RX_RING zero-copy between kernel- and user space that can be reused, and much more features. So instead of re-implementing all of this, we simply pass the skb to a given PF_PACKET socket for further analysis. Another nice benefit that comes from that is that no code needs to be changed in user space packet analyzers (maybe adding a dissector, but not more), thus out of the box, we can already capture pcap files of netlink traffic to debug/troubleshoot netlink problems. Also thanks goes to Thomas Graf, Flavio Leitner, Jesper Dangaard Brouer. [1] http://marc.info/?l=linux-netdev&m=113813401516110 Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/net/Kconfig')
-rw-r--r--drivers/net/Kconfig10
1 files changed, 10 insertions, 0 deletions
diff --git a/drivers/net/Kconfig b/drivers/net/Kconfig
index 00aba08f01a9..b45b240889f5 100644
--- a/drivers/net/Kconfig
+++ b/drivers/net/Kconfig
@@ -240,6 +240,16 @@ config VIRTIO_NET
This is the virtual network driver for virtio. It can be used with
lguest or QEMU based VMMs (like KVM or Xen). Say Y or M.
+config NLMON
+ tristate "Virtual netlink monitoring device"
+ ---help---
+ This option enables a monitoring net device for netlink skbs. The
+ purpose of this is to analyze netlink messages with packet sockets.
+ Thus applications like tcpdump will be able to see local netlink
+ messages if they tap into the netlink device, record pcaps for further
+ diagnostics, etc. This is mostly intended for developers or support
+ to debug netlink issues. If unsure, say N.
+
endif # NET_CORE
config SUNGEM_PHY