Re: patch for common networking error messages

From: Janice Girouard (
Date: Mon Jun 16 2003 - 19:44:22 EST

From: David S. Miller" <>
   Date: Mon, 16 Jun 2003 17:50:08 -0500

   If you want events, standardize events and push them over
   a queueing based communications channel to userspace, namely
   using netlink sockets.

It sounds like you are proposing a new family for the netlink
subsystem. I've included a list of the families I see in 2.5.70
the end of this note. I'm trying to understand which family handles
events such as link state changes or device initialization failure?
It sounds like you're proposing somethink equivalent to
NETLINK_TCP_DIAG. Is that right?

There seems to be some overlap between netlink and netdev notifier
events. Netdev notifier reports many key events. One event I don't
see reported is any indication that device initialization failed.
#define NETDEV_UP 0x0001
#define NETDEV_DOWN 0x0002
#define NETDEV_REBOOT 0x0003
#define NETDEV_CHANGE 0x0004
#define NETDEV_REGISTER 0x0005
#define NETDEV_UNREGISTER 0x0006
#define NETDEV_CHANGEMTU 0x0007
#define NETDEV_CHANGEADDR 0x0008
#define NETDEV_GOING_DOWN 0x0009

One issue with netdev, is that it doesn't seem to allow
for the flexibility of the information passed that netlink has.
For example, when you issue a NETDEV_CHANGE, it's not clear
from the event what the specific change was.

NETLINK 2.5.70


#define NETLINK_ROUTE 0 /* Routing/device hook */
#define NETLINK_SKIP 1 /* Reserved for ENskip */
#define NETLINK_USERSOCK 2 /* Reserved for user mode socket protocols */
#define NETLINK_FIREWALL 3 /* Firewalling hook */
#define NETLINK_TCPDIAG 4 /* TCP socket monitoring */
#define NETLINK_NFLOG 5 /* netfilter/iptables ULOG */
#define NETLINK_XFRM 6 /* ipsec */
#define NETLINK_ARPD 8
#define NETLINK_ROUTE6 11 /* af_inet6 route comm channel */
#define NETLINK_IP6_FW 13
#define NETLINK_DNRTMSG 14 /* DECnet routing messages */
#define NETLINK_TAPBASE 16 /* 16 to 31 are ethertap */

Descriptions for many of these events can be found at

       Receives routing updates and may be used
       to modify the IPv4 routing table (see
       Receives packets sent by the IPv4 firewall code.
       For managing the arp table in user space.
       Receives and sends IPv6 routing table updates.
       to receive packets that failed the IPv6 firewall
       checks (currently not implemented).
       are the instances of the ethertap device. Ethertap
       is a pseudo network tunnel device that allows an
       ethernet driver to be simulated from user space.
       Reserved for ENskip.
       is reserved for future user space protocols.

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