I'm trying to make a 6rd pseudo-device

[Patrick Klos <patrick%klos.com@localhost>]

Hello tech-net:

I am trying to make my own 6rd pseudo-device for NetBSD (partly, to try 
to use Comcast's 6rd support, and partly to learn more about how these 
kinds of drivers work?).  I'm building with current (5.99.43).

I modeled my 'sixrd' driver after the 'stf' driver since they're both 
doing almost the same tunneling with just a few different rules.

After creating the device, I configure it with the IPv6 address 
2001:55c:62d8:93c7::1:

   ifconfig sixrd0 inet6 2001:55c:62d8:93c7::1 prefixlen 32

Then I try to ping6 to 2001:55c:62d8:93c7::2 which should force the 
packets to/thru my driver, but instead, I get the following:

  lily# ping6 2001:55c:45fc:5042::2
  PING6(56=40+8+8 bytes) 2001:55c:62d8:93c7::1 --> 2001:55c:45fc:5042::2
  ping6: sendmsg: Message too long
  ping6: wrote 2001:55c:45fc:5042::2 16 chars, ret=-1
  ping6: sendmsg: Message too long
  ping6: wrote 2001:55c:45fc:5042::2 16 chars, ret=-1
  ping6: sendmsg: Message too long
  ping6: wrote 2001:55c:45fc:5042::2 16 chars, ret=-1
  ^C
  --- 2001:55c:45fc:5042::2 ping6 statistics ---
  3 packets transmitted, 0 packets received, 100.0% packet loss

I have a debug statement in the sixrd_output() routine, so I'd see if 
any packets were trying to be sent.

It's almost as if the IPv6 stack is checking the length, and thinking 
the packet is too big to send on the target interface? 

My device's settings are all identical to what the stf driver uses.  Any 
ideas?

Thanks,

Patrick Klos