A major overhaul of the CARP implementation. The ip_carp.c was started

from scratch, copying needed functionality from the old implemenation
on demand, with a thorough review of all code. The main change is that
interface layer has been removed from the CARP. Now redundant addresses
are configured exactly on the interfaces, they run on.

The CARP configuration itself is, as before, configured and read via
SIOCSVH/SIOCGVH ioctls. A new prefix created with SIOCAIFADDR or
SIOCAIFADDR_IN6 may now be configured to a particular virtual host id,
which makes the prefix redundant.

ifconfig(8) semantics has been changed too: now one doesn't need
to clone carpXX interface, he/she should directly configure a vhid
on a Ethernet interface.

To supply vhid data from the kernel to an application the getifaddrs(8)
function had been changed to pass ifam_data with each address. [1]

The new implementation definitely closes all PRs related to carp(4)
being an interface, and may close several others. It also allows
to run a single redundant IP per interface.

Big thanks to Bjoern Zeeb for his help with inet6 part of patch, for
idea on using ifam_data and for several rounds of reviewing!

PR:		kern/117000, kern/126945, kern/126714, kern/120130, kern/117448
Reviewed by:	bz
Submitted by:	bz [1]

1 files changed, 35 insertions, 11 deletions

diff --git a/sbin/ifconfig/ifconfig.8 b/sbin/ifconfig/ifconfig.8
index c6b8ea3..afee726 100644
--- a/sbin/ifconfig/ifconfig.8
+++ b/sbin/ifconfig/ifconfig.8
@@ -28,7 +28,7 @@
 .\"     From: @(#)ifconfig.8	8.3 (Berkeley) 1/5/94
 .\" $FreeBSD$
 .\"
-.Dd November 12, 2011
+.Dd December 16, 2011
 .Dt IFCONFIG 8
 .Os
 .Sh NAME
@@ -2445,16 +2445,36 @@ The
 argument is useless and hence deprecated.
 .El
 .Pp
-The following parameters are specific to
+The following parameters are used to configure
 .Xr carp 4
-interfaces:
+protocol on an interface:
 .Bl -tag -width indent
+.It Cm vhid Ar n
+Set the virtual host ID.
+This is a required setting to initiate
+.Xr carp 4 .
+If the virtual host ID doesn't exist yet, it is created and attached to the
+interface, otherwise configuration of an existing vhid is adjusted.
+If the
+.Cm vhid
+keyword is supplied along with an
+.Dq inet6
+or
+.Dq inet
+address, then this address is configured to be run under control of the
+specified vhid.
+Whenever a last address that refers to a particular vhid is removed from an
+interface, the vhid is automatically removed from interface and destroyed.
+Any other configuration parameters for the
+.Xr carp 4
+protocol should be supplied along with the
+.Cm vhid
+keyword.
+Acceptable values for vhid are 1 to 255.
 .It Cm advbase Ar seconds
 Specifies the base of the advertisement interval in seconds.
 The acceptable values are 1 to 255.
 The default value is 1.
-.\" The default value is
-.\" .Dv CARP_DFLTINTV .
 .It Cm advskew Ar interval
 Specifies the skew to add to the base advertisement interval to
 make one host advertise slower than another host.
@@ -2464,10 +2484,8 @@ The default value is 0.
 .It Cm pass Ar phrase
 Set the authentication key to
 .Ar phrase .
-.It Cm vhid Ar n
-Set the virtual host ID.
-This is a required setting.
-Acceptable values are 1 to 255.
+.It Cm state Ar MASTER|BACKUP
+Forcibly change state of a given vhid.
 .El
 .Pp
 The
@@ -2530,8 +2548,9 @@ The
 .Fl k
 flag causes keying information for the interface, if available, to be
 printed.
-For example, the values of 802.11 WEP keys will be printed, if accessible to
-the current user.
+For example, the values of 802.11 WEP keys and
+.Xr carp 4
+passphrases will be printed, if accessible to the current user.
 This information is not printed by default, as it may be considered
 sensitive.
 .Pp 
@@ -2593,6 +2612,11 @@ as a synonym for the canonical form of the option
 .Fl alias :
 .Dl # ifconfig em0 inet6 2001:db8:bdbd::123/48 delete
 .Pp
+Configure a single CARP redundant address on igb0, and then switch it
+to be master:
+.Dl # ifconfig igb0 vhid 1 10.0.0.1/24 pass foobar
+.Dl # ifconfig igb0 vhid 1 state master
+.Pp
 Configure the interface
 .Li xl0 ,
 to use 100baseTX, full duplex Ethernet media options: