>Number:         189088
>Category:       kern
>Synopsis:       Assigning the same IP to multiple interfaces in different FIBs 
>creates a host route for only one.
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Mon Apr 28 22:30:00 UTC 2014
>Closed-Date:
>Last-Modified:
>Originator:     Alan Somers
>Release:        11.0 CURRENT
>Organization:
Spectra Logic
>Environment:
FreeBSD alans-fbsd-head 11.0-CURRENT FreeBSD 11.0-CURRENT #55 r265061M: Mon Apr 
28 15:08:01 MDT 2014     
[email protected]:/vmpool/obj/usr/home/alans/freebsd/head/sys/GENERIC  
amd64
>Description:
Assigning the same IP to multiple interfaces simultaneously sounds insane, but 
some people do it.  However, if you assign them to separate FIBs as well as 
separate interfaces, bad stuff happens.  For one thing, only the first FIB used 
will get a host route.  For another, if you delete the addresses in FIFO order 
the host route will never get deleted (though it will if you delete them in 
LIFO order).
>How-To-Repeat:
On a system with net.add_addr_allfibs=0 and net.fibs=4, Run the following 
commands:

# ifconfig tap0 create
# ifconfig tap1 create
# ifconfig tap0 192.0.2.2/32 fib 2
# ifconfig tap1 192.0.2.2/32 fib 3
# setfib 2 netstat -rn -f inet
Routing tables (fib: 2)

Internet:
Destination        Gateway            Flags    Netif Expire
192.0.2.2          link#3             UHS       lo0
192.0.2.2/32       link#3             U        tap0
# setfib 3 netstat -rn -f inet
Routing tables (fib: 3)

Internet:
Destination        Gateway            Flags    Netif Expire
192.0.2.2/32       link#4             U        tap1


Notice that FIB 3 does not get a 192.0.2.2 host route.  Now try deleting the 
addresses in FIFO order:


# ifconfig tap0 -alias 192.0.2.2
# ifconfig tap1 -alias 192.0.2.2
# setfib 2 netstat -rn -f inet
Routing tables (fib: 2)

Internet:
Destination        Gateway            Flags    Netif Expire
192.0.2.2          link#4             UHS       lo0
>Fix:


>Release-Note:
>Audit-Trail:
>Unformatted:
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