[Simh] VAX-11/780 DEUNA Ethernet problems with 4.3BSD

Sat Sep 13 09:24:40 EDT 2008

Does anyone have any thoughts on this?

I've got no idea how to approach this problem, so would appreciate any thoughts.

Roy

From: royhills at hotmail.com
To: simh at trailing-edge.com
Date: Fri, 15 Aug 2008 19:08:44 +0100
Subject: [Simh] VAX-11/780 DEUNA Ethernet problems with 4.3BSD

I'm running 4.3BSD on the SIMH VAX-11/780 emulator, and I'm having some issues with the emulated DEUNA Ethernet adapter.  I'm using SIMH version 3.8 on Windows XP.

I've got two issues:

1.  The Ethernet adapter does not appear to respond to broadcasts (i.e. destination address ff:ff:ff:ff:ff:ff), so the system does not answer ARP requests.

Here's an example tcpdump output.  The client is at IP address 192.168.1.57, and the 4.3BSD machine is at 192.168.1.70:

18:27:03.623364 00:0c:29:01:67:5a > ff:ff:ff:ff:ff:ff, ethertype ARP (0x0806), length 42: arp who-has 192.168.1.70 tell 192.168.1.57
18:27:03.725393 00:0c:29:01:67:5a > ff:ff:ff:ff:ff:ff, ethertype ARP (0x0806), length 42: arp who-has 192.168.1.70 tell 192.168.1.57

2.  The Ethernet adapter responds to packets sent to its own address, but replies from seemingly random source addresses.

Here's an example of an ARP request sent to the SIMH system's MAC address of 08:00:2b:12:34:56.  We see that it replies with the correct MAC address in the ARP packet, but the source address in the Ethernet frame is aa:fd:00:00:00:00

18:29:48.059696 00:0c:29:01:67:5a > 08:00:2b:12:34:56, ethertype ARP (0x0806), length 42: arp who-has 192.168.1.70 tell 192.168.1.57
18:29:48.060160 aa:fd:00:00:00:00 > 00:0c:29:01:67:5a, ethertype ARP (0x0806), length 60: arp reply 192.168.1.70 is-at 08:00:2b:12:34:56

Sending another directed ARP request gets a reply with a different source MAC address:

18:32:05.439533 00:0c:29:01:67:5a > 08:00:2b:12:34:56, ethertype ARP (0x0806), length 42: arp who-has 192.168.1.70 tell 192.168.1.57
18:32:05.445380 ab:b1:00:00:00:00 > 00:0c:29:01:67:5a, ethertype ARP (0x0806), length 60: arp reply 192.168.1.70 is-at 08:00:2b:12:34:56

If I put a static ARP mapping on the client, I can telnet to the SIMH system and login.  The telnet session also uses random source addresses in the ethernet header, but surprisingly still works OK:

18:38:19.567264 00:0c:29:01:67:5a > 08:00:2b:12:34:56, IPv4, length 74: 192.168.1.57.4658 > 192.168.1.70.23: tcp 0
18:38:19.574243 33:00:00:00:07:00 > 00:0c:29:01:67:5a, IPv4, length 60: 192.168.1.70.23 > 192.168.1.57.4658: tcp 0
18:38:19.574287 00:0c:29:01:67:5a > 08:00:2b:12:34:56, IPv4, length 54: 192.168.1.57.4658 > 192.168.1.70.23: tcp 0
18:38:19.576378 00:0c:29:01:67:5a > 08:00:2b:12:34:56, IPv4, length 78: 192.168.1.57.4658 > 192.168.1.70.23: tcp 24
18:38:19.589707 00:00:00:00:00:00 > 00:0c:29:01:67:5a, IPv4, length 60: 192.168.1.70.23 > 192.168.1.57.4658: tcp 3
18:38:19.589795 00:0c:29:01:67:5a > 08:00:2b:12:34:56, IPv4, length 54: 192.168.1.57.4658 > 192.168.1.70.23: tcp 0
18:38:19.598110 27:ff:fd:05:07:00 > 00:0c:29:01:67:5a, IPv4, length 81: 192.168.1.70.23 > 192.168.1.57.4658: tcp 27
18:38:19.598160 00:0c:29:01:67:5a > 08:00:2b:12:34:56, IPv4, length 54: 192.168.1.57.4658 > 192.168.1.70.23: tcp 0
18:38:19.599593 00:0c:29:01:67:5a > 08:00:2b:12:34:56, IPv4, length 65: 192.168.1.57.4658 > 192.168.1.70.23: tcp 11
18:38:19.609339 1e:01:00:00:c0:a8 > 00:0c:29:01:67:5a, IPv4, length 107: 192.168.1.70.23 > 192.168.1.57.4658: tcp 53
18:38:19.609920 00:0c:29:01:67:5a > 08:00:2b:12:34:56, IPv4, length 60: 192.168.1.57.4658 > 192.168.1.70.23: tcp 6
18:38:19.616475 1e:01:00:00:c0:a8 > 00:0c:29:01:67:5a, IPv4, length 61: 192.168.1.70.23 > 192.168.1.57.4658: tcp 7

The DEUNA configuration in the SIMH config file is:

set xu enabled
set xu mac=08-00-2B-12-34-56
attach xu \Device\NPF_{A390A62C-E18B-45FC-A99F-FB039C5B4032}

The SIMH system sees the DEUNA at boot, and gets the correct MAC address:

de0 at uba0 csr 174510 vec 120, ipl 15
de0: hardware address 08:00:2b:12:34:56

And ifconfig shows the device OK:

de0: flags=63<UP,BROADCAST,NOTRAILERS,RUNNING>
        inet 192.168.1.70 netmask ffffff00 broadcast 192.168.1.255

I'm running the original 1986 vintage 4.3BSD from the CSRG Archive CDROM installed on a virtual RA81 disk.  Apart from the DEUNA issue, it's working fine.

Any ideas?

Roy

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