i386/93448: CARP advskew not propagated to VRRP packets

[Andrew Webster]

>Number:         93448
>Category:       i386
>Synopsis:       CARP advskew not propagated to VRRP packets
>Confidential:   no
>Severity:       non-critical
>Priority:       medium
>Responsible:    freebsd-i386
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Thu Feb 16 19:10:03 GMT 2006
>Closed-Date:
>Last-Modified:
>Originator:     Andrew Webster
>Release:        5.4p8
>Organization:
ConnecTalk Inc.
>Environment:
FreeBSD carp1.connectalk.com 5.4-RELEASE-p8 FreeBSD 5.4-RELEASE-p8 #0: Tue Dec 20 11:39:40 EST 2005     root at serialtest.connectalk.com:/usr/src/sys/i386/compile/CARP  i386              
>Description:
Carp advskew values of < 240 are ignored and set to 240.

Carp interface configured as follows:
# ifconfig em1
em1: flags=8943<UP,BROADCAST,RUNNING,PROMISC,SIMPLEX,MULTICAST> mtu 1500
        options=b<RXCSUM,TXCSUM,VLAN_MTU>
        inet6 fe80::20c:29ff:fef1:9f4c%em1 prefixlen 64 scopeid 0x2 
        inet 10.10.1.2 netmask 0xffffff00 broadcast 10.10.1.255
        ether 00:0c:29:f1:9f:4c
        media: Ethernet autoselect (1000baseTX <full-duplex>)
        status: active
# ifconfig carp0
carp0: flags=41<UP,RUNNING> mtu 1500
        inet 10.10.1.1 netmask 0xffffff00 
        carp: MASTER vhid 10 advbase 1 advskew 1

# tcpdump -n -i em1
13:58:14.738030 IP 10.10.1.2 > 224.0.0.18: VRRPv2, Advertisement, vrid 10, prio 240, authtype none, intvl 1s, length 36
13:58:16.687548 IP 10.10.1.2 > 224.0.0.18: VRRPv2, Advertisement, vrid 10, prio 240, authtype none, intvl 1s, length 36

Notice prio is 240, not 1.  If set to > 240, then it follows.

# ifconfig carp0 advskew 242
# tcpdump -n -i em1
13:59:07.529908 IP 10.10.1.2 > 224.0.0.18: VRRPv2, Advertisement, vrid 10, prio 242, authtype none, intvl 1s, length 36
13:59:09.488462 IP 10.10.1.2 > 224.0.0.18: VRRPv2, Advertisement, vrid 10, prio 242, authtype none, intvl 1s, length 36

Now it is 242.
>How-To-Repeat:
# ifconfig em1 10.10.1.2/24
# ifconfig carp0 create
# ifconfig carp0 vhid 10 advbase 1 advskew 1
# ifconfig carp0 10.10.1.1/24
# ifconfig carp0 up
# tcpdump -n -i em1              
>Fix:
Looks like carp_suppress_preempt is being incorrectly set to true.
Perhaps in static void carp_sc_state_locked(struct carp_softc *sc)              
Actual fix ?
>Release-Note:
>Audit-Trail:
>Unformatted: