Subject: cannot delete & duplicate entries WAS: Re: strange routing behavior: wrong route picked
To: None <tech-net@netbsd.org, tech-kern@netbsd.org>
From: Tad Hunt <tad@entrisphere.com>
List: tech-net
Date: 11/07/2002 20:03:23
More related oddities.  As before, "netstat -nr" tells me that
there is a route to 192.168.1.2 through 192.168.1.1.  However,
"route get 192.168.1.2" gives the default route.

Attempting to delete the route to 192.168.1.2 gives an error, as
if it cannot find such a route.  If I add the route, netstat shows
two routes, but now the packets go where they are supposed to.

Thanks,
	-Tad

-------------------------------------------------------------------------------
# netstat -nr
Routing tables

Internet:
Destination        Gateway            Flags     Refs     Use    Mtu  Interface
default            192.168.167.1      UGS         3     3866   1500  fe0
127                127.0.0.1          UR          0        0  33228  lo0
127.0.0.1          127.0.0.1          UH          1        0  33228  lo0
192.168.1.1        127.0.0.1          UGH         0        0  33228  lo0
192.168.1.2        192.168.1.1        UH          0        0    512  tun0
192.168.167        link#1             UC          0        0   1500  fe0
192.168.167.1      00:01:30:1e:4d:c0  UHL         1        0   1500  fe0
# 
# 
# 
# route get 192.168.1.2
   route to: 192.168.1.2
destination: default
       mask: default
    gateway: 192.168.167.1
 local addr: fab1197.int.entrisphere.com
  interface: fe0
      flags: <UP,GATEWAY,DONE,STATIC>
 recvpipe  sendpipe  ssthresh  rtt,msec    rttvar  hopcount      mtu     expire
       0         0         0         0         0         0      1500         0 
# 
# 
# route delete -host 192.168.1.2
writing to routing socket: No such process
delete host 192.168.1.2: Bad file descriptor
# 
# route add -host 192.168.1.2 192.168.1.1
add host 192.168.1.2: gateway 192.168.1.1
# 
# 
# route get 192.168.1.2
   route to: 192.168.1.2
destination: 192.168.1.2
    gateway: 192.168.1.1
 local addr: 192.168.1.1
  interface: tun0
      flags: <UP,GATEWAY,HOST,DONE,STATIC>
 recvpipe  sendpipe  ssthresh  rtt,msec    rttvar  hopcount      mtu     expire
       0         0         0         0         0         0     33228         0 
# 
# 
# netstat -nr
Routing tables

Internet:
Destination        Gateway            Flags     Refs     Use    Mtu  Interface
default            192.168.167.1      UGS         3     4169   1500  fe0
127                127.0.0.1          UR          0        0  33228  lo0
127.0.0.1          127.0.0.1          UH          1        0  33228  lo0
192.168.1.1        127.0.0.1          UGH         1        0  33228  lo0
192.168.1.2        192.168.1.1        UGHS        0        0  33228  tun0
192.168.1.2        192.168.1.1        UH          0        0    512  tun0
192.168.167        link#1             UC          0        0   1500  fe0
192.168.167.1      00:01:30:1e:4d:c0  UHL         1        0   1500  fe0
# 

In message <MOBYDICKlrjbudzxxfY00000123@mobydick.int.entrisphere.com>, you said:
;
;I've attached what I think is the relevant output below.
;
;Notice the route for 192.168.1.1, which should be reachable via
;interface tun8.  For some reason that I cannot fathom, "route get
;192.168.1.1" tells me that it's using the default route out the
;"fe0" interface, instead of the the more specific route (which
;appears to be marked UP) as far as I can tell.
;
;According to route(4), the most specific route should be picked:
;
;     "When routing a packet, the kernel will attempt to find the
;     most specific route matching the destination.  (If there are
;     two different mask and value-under-the-mask pairs that match,
;     the more specific is the one with more bits in the mask.  A
;     route to a host is regarded as being supplied with a mask of
;     as many ones as there are bits in the destination).  If no
;     entry is found, the destination is declared to be unreachable,
;     and a routing-miss message is generated if there are any
;     listers on the routing control socket described below.
;
;Does anyone have any idea what is happening here?
;
;If additional information would be helpful, let me know and I'll provide
;it!
;
;Background:
;* I'm running gated(8)
;
;* I seem to notice this problem after bringing an interface down
;  and back up.  It works correctly after the interface comes
;  up the first time.  The "route get" starts returning the wrong route
;  after the interface goes down and comes back up.
;
;
;Thanks,
;	-Tad
;
;    ----------------------------------------------------------------------
;
;# ifconfig tun8
;tun8: flags=51<UP,POINTOPOINT,RUNNING> mtu 576
;        inet 192.168.1.2 -> 192.168.1.1 netmask 0xffffffff
;#
;# netstat -nr
;Routing tables
;
;Internet:
;Destination        Gateway            Flags     Refs     Use    Mtu  Interface
;default            192.168.167.1      UGS         2     2194   1500  fe0
;127                127.0.0.1          UR          0        0  33228  lo0
;127.0.0.1          127.0.0.1          UH          1        3  33228  lo0
;192.168.1.1        192.168.1.2        UH          0        0    576  tun8
;192.168.1.2        127.0.0.1          UGH         0        3  33228  lo0
;192.168.167        link#1             UC          0        0   1500  fe0
;192.168.167.1      00:01:30:1e:4d:c0  UHL         1        0   1500  fe0
;#
;# route get 192.168.1.1
;   route to: 192.168.1.1
;destination: default
;       mask: default
;    gateway: 192.168.167.1
; local addr: fab1318.int.entrisphere.com
;  interface: fe0
;      flags: <UP,GATEWAY,DONE,STATIC>
; recvpipe  sendpipe  ssthresh  rtt,msec    rttvar  hopcount      mtu     expire
;       0         0         0         0         0         0      1500         0 
;#