Skip to content
Switch branches/tags

Name already in use

A tag already exists with the provided branch name. Many Git commands accept both tag and branch names, so creating this branch may cause unexpected behavior. Are you sure you want to create this branch?
Go to file
Cannot retrieve contributors at this time
This file contains information about the SIMH Ethernet package.
The XQ emulator is a host-independent software emulation of Digital's
DELQA-T (M7516-YM), DELQA (M7516) and DEQNA (M7504) Q-bus Ethernet cards
for the SIMH emulator.
The XU emulator is a host-independent software emulation of Digital's DEUNA
(M7792/M7793) and DELUA (M7521) Unibus Ethernet cards for the SIMH emulator.
The XQ and XU simulators use the Sim_Ether module to execute host-specific
packet reads and writes, since all operating systems talk to real Ethernet
cards/controllers differently. See the comments at the top of sim_ether.c
for the list of currently supported host platforms.
The Sim_Ether module sets the selected Ethernet card into
promiscuous mode to gather all packets, then filters out the packets that it
doesn't want. In Windows, packets having the same source MAC address as the
controller are ignored for WinPCAP compatibility (see Windows notes below).
If your Ethernet card is plugged into a switch, the promiscuous mode setting
should not cause much of a problem, since the switch will still filter out
most of the undesirable traffic. You will only see "excessive" traffic if you
are on a direct or hub(repeater) segment.
On Windows using the WinPcap interface, the simulated computer can "talk" to
the host computer on the same interface. On other platforms with libpcap
(*nix), the simulated computer can not "talk" to the host computer via the
selected interface, since simulator transmitted packets are not received
by the host's network stack. The workaround for this is to use a second NIC
in the host and connect them both into the same network; then the host and
the simulator can communicate over the physical LAN.
Integrated Universal TUN/TAP support provides another solution for the above
dual-NIC problem for systems that support Universal TUN/TAP. Since the TUN/TAP
interface is a pseudo network interface, the host can create a TAP device for
the simulator and then bridge or route packets between the TAP device and the
real network interface. Note that the TAP device and any bridging or routing
must be established before running the simulator; SIMH does not create,
bridge, or route TAP devices for you.
Integrated Universal TUN/TAP support can be used for host<->simulator network
traffic (on the platforms where it is available) by using the SIMH command:
"attach xq tap:tapN" (i.e. attach xq tap:tap0). Platforms that this has been
tested on include: Linux, FreeBSD, OpenBSD, NetBSD and OSX. Each of these
platforms has some way to create a tap pseudo device (and possibly then to
bridge it with a physical network interface).
The following steps were performed to get a working SIMH vax simulator
sharing a physical NIC and allowing Host<->SIMH vax communications:
Linux (Ubuntu 10.04):
apt-get install make
apt-get install libpcap-dev
apt-get install bridge-utils
apt-get install uml-utilities
HOSTIP=`/sbin/ifconfig eth0 | grep "inet addr" | gawk -- '{ print $2 }' | gawk -F : -- '{ print $2 }'`
HOSTNETMASK=`/sbin/ifconfig eth0 | grep "inet addr" | gawk -- '{ print $4 }' | gawk -F : -- '{ print $2 }'`
HOSTBCASTADDR=`/sbin/ifconfig eth0 | grep "inet addr" | gawk -- '{ print $3 }' | gawk -F : -- '{ print $2 }'`
HOSTDEFAULTGATEWAY=`/sbin/route -n | grep ^ | gawk -- '{ print $2 }'`
/usr/sbin/tunctl -t tap0 [-u someuser]
/sbin/ifconfig tap0 up
# Now convert eth0 to a bridge and bridge it with the TAP interface
/usr/sbin/brctl addbr br0
/usr/sbin/brctl addif br0 eth0
/usr/sbin/brctl setfd br0 0
/sbin/ifconfig eth0
/sbin/ifconfig br0 $HOSTIP netmask $HOSTNETMASK broadcast $HOSTBCASTADDR up
# set the default route to the br0 interface
/sbin/route add -net gw $HOSTDEFAULTGATEWAY
# bridge in the tap device
/usr/sbin/brctl addif br0 tap0
/sbin/ifconfig tap0
# Run simulator and "attach xq tap:tap0"
Linux (Fedora Core 18, 20, CentOS, RedHat, etc.):
yum install gcc
yum install libpcap-devel
yum install uml-utilities
Linux (Centos 6.x):
yum install gcc
yum install libpcap-devel
yum install uml_utilities
OpenBSD (OpenBSD 4.6)
/sbin/ifconfig tun0 create
/sbin/ifconfig tun0 link0
/sbin/ifconfig tun0 up
/sbin/ifconfig bridge0 create
/sbin/brconfig bridge0 fwddelay 4
/sbin/brconfig bridge0 add em0 add tun0 # Change em0 to reflect your physical NIC name
/sbin/brconfig bridge0 up
# Run simulator and "attach xq tap:tun0"
FreeBSD (FreeBSD 11.3)
/sbin/ifconfig tap0 create
/sbin/ifconfig tap0 up
/sbin/ifconfig bridge0 create
/sbin/ifconfig bridge0 addm em0 addm tap0 # Change em0 to reflect your physical NIC name
/sbin/ifconfig bridge0 up
# Run simulator and "attach xq tap:tap0"
NetBSD (NetBSD 5.0.2)
/sbin/ifconfig tap0 create
/sbin/ifconfig tap0 up
/sbin/ifconfig bridge0 create
/sbin/brconfig bridge0 fwddelay 1
/sbin/brconfig bridge0 add wm0 add tap0 # Change wm0 to reflect your physical NIC name
/sbin/brconfig bridge0 up
# Run simulator and "attach xq tap:tap0"
OSX (Snow Leopard)
OSX Does NOT have native support for tun/tap interfaces. It also does not have native
support for bridging.
Mattias Nissler has created tun/tap functionality available at http://tuntaposx,
We'll punt on bridging for the sake of this example and move on to use a basic tap
based internal network so a host and guest can communicate directly.
Download the install package from:
Expand the tarball to a directory.
Invoke the package installer tuntap_20111101.pkg
Click through the various prompts accepting things and eventually installing the package.
# Build and Run simulator and:
sim> attach xq tap:tap0
sim> ! ifconfig tap0 netmask
Simulated system uses IP address and host uses
and things work.
You must run as root for this to work.
An alternative to direct pcap and tun/tap networking on *nix environments is
VDE (Virtual Distributed Ethernet).
Note 1: Using vde based networking is likely more flexible, but it isn't
nearly as efficient. Host OS overhead will always be higher when
vde networking is used as compared to native pcap and/or tun/tap
Note 2: Root access will likely be needed to configure or start the vde
environment prior to starting a simulator which may use it.
Note 3: Simulators running using VDE networking can run without root
Linux (Ubuntu 11.10):
apt-get install make
apt-get install libvdeplug2-dev
apt-get install vde2
vde_switch -s /tmp/switch1 -tap tap0 -m 666
ifconfig tap0 netmask up
# Build and Run simulator and:
sim> attach xq vde:/tmp/switch1 #simulator uses IP address
The macports package manager ( can be used to
install the net/vde2 package.
Another alternative to direct pcap and tun/tap networking on all environments is
NAT (SLiRP) networking. NAT networking is limited to only IP network protocols
so DECnet, LAT and Clusting can't work on a NAT connected interface, but this may
be the easiest solution for many folks.
sim> attach xq nat:
The simulator can use static IP addresses of thru with a
netmask of and a gateway of and a nameserver of
If the simulated machine uses DHCP it will get the address Various
NAT based parameters can be configured on the attach command. HELP XQ ATTACH
will provide useful information. Host to simulator connectivitiy can be
achieved for a simulator which gets its IP address via DHCP with the following
sim> attach xq nat:tcp=2323:,tcp=2121:
The host computer can telnet to localhost:2323 to reach the simulator via
telnet, etc.
Additionally NAT based networking is useful to allow host systems with WiFi
networking to a) reach the simulated system and b) allow the simulated system
to reach out to the Internet.
Note: As mentioned above, NAT networking is specifically capable of providing
TCP/IP connectivity. Only expect TCP and UDP traffic to pass through
the interface. Do not expect ICMP traffic (ping mostly) to traverse
the NAT boundary. This restriction is a conseqence of host platform
and network limitations regarding direct user mode code generating ICMP
Windows notes:
1. The Npcap package available from is the preferred
interface for Windows 7 onward since the original WinPCAP 4.1.3 package
from is no longer
developed or supported. These packages for windows simulate the libpcap
package that is freely available for un*x systems.
2. You must *install* the Npcap or WinPCAP runtime package.
3. The first time the Npcap/WinPCAP driver is used, it will be dynamically
loaded, and the user must be an Administrator on the machine to do so.
If you need to run as an unprivileged user, you must set the "npf" driver
to autostart.
Current Npcap and WinPcap installers provide an option to configure this
at installation time, so if that choice is made, then there is no need for
administrator privileged to run simulators with network support.
Building on Windows:
You should be able to build with any of the free compiler environments
available on the Windows platform. If you want to use the Visual C++
Express 2008 or 2010 interactive development environments, read the file
".\Visual Studio Projects\0ReadMe_Projects.txt" for details about the
required dependencies. Alternatively, you can build simh with networking
support using the MinGW GCC compiler environment (32 bit) or the cygwin
environment. Each of these Visual C++, MinGW and cygwin build environments
require Npcap or WinPcap and Posix threading packages being available.
These should be located in a directory structure parallel to the current
simulator source directory.
For Example, the directory structure should look like:
.../simh/simh-master/Visual Studio Projects/simh.sln
.../simh/simh-master/Visual Studio Projects/VAX.vcproj
The contents of the windows-build directory can be downloaded from:
This archive of dependent components for Windows simulators will
automatically be downloaded, if needed, when building with Visual Studio.
There are Windows batch files provided to initiate compiles using the MinGW
compiler tool chain. These batch files are located in the same directory
as this file and are called: build_mingw.bat, build_mingw_ether.bat, and
build_mingw_noasync.bat. These batch files each presume that the MinGW
toolchain is either in the current path or, if not that it is located at
C:\MinGW\bin. These batch files merely invoke the MinGW make (GNU make)
passing some specific arguments along with the optional arguments the batch
file is invoked with.
The current windows network built binaries will run on any system without
regard to whether or not Npcap or WinPcap is installed, and will provide
Network functionality when Npcap or WinPcap is available.
Linux, {Free|Net|Open}BSD, OS/X, and Un*x notes:
----- WARNING ----- WARNING ----- WARNING ----- WARNING ----- WARNING -----
Sim_Ether has been reworked to be more universal; because of this, you will
need to get a version of libpcap that is 0.9 or greater. All current Linux
distributions provide a libpcap-dev package which has the needed version
of libpcap and the required components to build applications using it.
If you are running an older Linux OS, you can download and build the required
library from - see the comments at the top of Sim_ether.c
for details.
----- WARNING ----- WARNING ----- WARNING ----- WARNING ----- WARNING -----
1. For all platforms, you must run SIMH(scp) with sufficient privilege to
allow the Ethernet card to be set into promiscuous mode and to write
packets through the driver.
a) For Windows systems this means having administrator privileges to
start the "npf" driver. The current WinPcap installer offers an
option to autostart the "npf" driver when the system boots.
Starting the "npf" driver at boot time means that simulators do
not need to run with administrator privileges.
b) For more recent Linux systems, The concepts leveraging "Filesystem
Capabilities" can be used to specifically grant the simh binary
the needed privileges to access the network. The article at:
describes how to do this for wireshark. The exact same capabilities
are needed by SIMH for network support. Use that article as a guide.
c) For Unix/Unix-like systems which use bpf devices (NetBSD,
OpenBSD, FreeBSD and OS/X) it is possible to set permissions on
the bpf devices to allow read and write access to users other
than root (For example: chmod 666 /dev/bpf*). Doing this, has
its own security issues.
d) For other platforms this will likely mean running as root.
Additional alternative methods for avoiding the 'run as root' requirement
will be welcomed.
2. If you want to use TAP devices, and any surrounding system network/bridge
setup must be done before running SIMH. However, once that is done
(possibly at system boot time), using the TAP devices can be done without
root privileges.
Building on Linux, {Free|Net|Open}BSD, OS/X, Solaris, other *nix:
1. Get/make/install the libpcap-dev package (or libpcap-devel) for your
operating system. Sources:
All :
Older versions of libpcap can be found, for various systems, at:
Linux :
Debian Based distributions:
# apt-get install libpcap-dev
RedHat/Fedora Based distributions:
# yum install libpcap-devel
OS/X : The libpcap components are installed as part of the Xcode
developer package. Instructions to install Xcode on various
OSX versions are available at:
Be sure to install the command line tools which are installed
with the command "xcode-select --install" in more recent
versions of the Apple developer support.
NOTE: The repositories for older versions of these platforms
don't contain a version of libpcap greater than 0.8.1.
However, most(all) recent releases of *nix environments
ship with sufficiently recent versions of libpcap either
automatically installed or available for installation as
part of the distribution.
The OS provided libpcap-dev components will be prefereable
to a package built from sources. This is
due to the fact that various OS supplied packages will
depend on the OS supplied libpcap. The improper build or
install of the source package can conflict
with the OS provided one and break the OS provided
applications (i.e. tcpdump and/or wireshark) as well as
not working correctly for use by simh.
2. If you install the vendor supplied libpcap-dev package then the simh
makefile will automatically use the vendor supplied library without any
additional arguments. If you have downloaded and built libpcap from, then the existing makefile will detect that this is
the case and try to use that.
3. The makefile defaults to building simulators with network support which
dynamically load the libpcap library. This means that the same simulator
binaries will run on any system whether or not libpcap is installed. If
you want to force direct libpcap linking during a build you do so by
typing 'make USE_NETWORK=1'. You must build with gcc to do this. There
is no observable benefit to directly linking against libpcap. Support
for directly linking libpcap is deprecated on all platforms except
Linux and macOS where it has already been removed.
4. Some platforms (HP-UX in particular) may not have vendor supplied libpcap
components available and installed with the operating system. The packages
which are available for this platform install include and library files in
user specified locations. When building on these platforms the library
path must be specified on the make command line. This can be done with:
'make LPATH=/usr/lib:/usr/local/lib'
5. Build it!
OpenVMS Alpha and OpenVMS Integrety (IA64) notes:
1. Ethernet support will only work on Alpha VMS 7.3-1 or later, which is
when required VCI promiscuous mode support was added. Hobbyists can
get the required version of VMS from the OpenVMS Alpha Hobbyist Kit 3.0.
Running a simulator built with Ethernet support on a version of VMS prior
to 7.3-1 will behave as if there is no Ethernet support built in due to
the inability of the software to set the PCAPVCM into promiscuous mode.
An example display of fully functional Ethernet support:
ETH devices:
0 we0 (VMS Device: _EWA0:)
1 we1 (VMS Device: _EWB0:)
An example display when the simulator was built without Ethernet support
or is not running the required version of VMS:
ETH devices:
no network devices are available
2. You must place the PCAPVCM.EXE execlet in SYS$LOADABLE_IMAGES before
running a simulator with Ethernet support. Note: This is done by the
build commands in descrip.mms.
3. You must have CMKRNL privilege to SHOW or ATTACH an Ethernet device;
alternatively, you can INSTALL the simulator with CMKRNL privilege.
4. If you use a second adapter to communicate to the host, SOME protocol
that creates an I/O structure (SCS, DECNET, TCP) must be running on the
adapter prior trying to connect with SIMH, or the host may crash.
The execlet is not written to create an I/O structure for the device.
Building on OpenVMS Alpha and OpenVMS Integrety (IA64):
The current descrip.mms file will build simulators capable of using
Ethernet support with them automatically. These currently are: VAX,
VAX780, and PDP11. The descrip.mms driven builds will also build the
pcap library and build and install the VCI execlet.
1. Fetch the VMS-PCAP zip file from:
2. Unzip it into the base of the SIMH distribution directory.
3. Build the simulator(s) with MMS or MMK:
$ MMx {VAX,PDP11,PDP10, etc...}
VAX simulator support:
An OpenVMS VAX v7.3 system with DECNET Phase IV, MultiNet 5.4, and LAT 5.3 has
been successfully run. Other testers have reported success booting NetBSD and
OpenVMS VAX 5.5-2 also.
PDP11 simulator support:
An RT-11 v5.3 system with a freeware TCP/IP stack has been successfully run.
Other testers have reported that RSX with DECNET and the NetBSD operating
systems also work. RSTS/E v10.1 has preliminary support - RSTS/E boots and
enables the XH (XQ) device - DECNET and LAT software have not been tested.
The XU module has been tested by a third party for basic packet functionality
under a modified RSX11M environment. I am unable to test it in-house until
someone can arrange to send me a disk image containing a stock RSTS/E or
RSX11M+ system image that also contains DECNET, LAT, and/or TCP/IP software.
How to debug problems with the Ethernet subsystems:
PLEASE read the host-specific notes in sim_ether.c!
While running SCP, the following commands can be used to enable debug messages:
Documentation of the functionality of these debug modifiers can be found in
pdp11_xq.h and pdp11_xu.h. Inline debugging has replaced the previous #ifdef
style of debugging, which required recompilation before debugging.
Things planned for future releases:
1. Full MOP implementation
Things which I need help with:
1. Information about Remote MOP processing
2. VAX/PDP-11 hardware diagnostics image files and docs, to test XQ thoroughly.
3. Feedback on operation with other VAX/PDP-11 OS's.
Please send all patches, questions, feedback, clarifications, and help to:
david DOT hittner AT ngc DOT com
Thanks, and Enjoy!!
Change Log
01-Mar-12 AGN Added support for building using Cygwin on Windows
01-Mar-12 MP Made host NIC address detection more robust on *nix platforms
and mad it work when compiling under Cygwin
29-Feb-12 MP Fixed MAC Address Conflict detection support
28-Feb-12 MP Fixed overrun bug in eth_devices which caused SEGFAULTs
28-Feb-12 MP Fixed internal loopback processing to only respond to loopback
packets addressed to the physical MAC or appropriate Multicast
or Broadcast addresses.
17-Nov-11 MP Added dynamic loading of libpcap on *nix platforms
30-Oct-11 MP Added support for vde (Virtual Distributed Ethernet) networking
29-Oct-11 MP Added support for integrated Tap networking interfaces on OSX
17-Aug-11 RMS Fix from Sergey Oboguev relating to XU and XQ Auto Config and
vector assignments
12-Aug-11 MP Cleaned up payload length determination
Fixed race condition detecting reflections when threaded
reading and writing is enabled
07-Jul-11 MB VMS Pcap (from Mike Burke)
- Fixed Alpha issues
- Added OpenVMS Integrety support
20-Apr-11 MP Fixed save/restore behavior
12-Jan-11 DTH Added SHOW XU FILTERS modifier
11-Jan-11 DTH Corrected DEUNA/DELUA SELFTEST command, enabling use by
VMS 3.7, VMS 4.7, and Ultrix 1.1
09-Jan-11 MP Fixed missing crc data when USE_READER_THREAD is defined and
crc's are needed (only the pdp11_xu)
16-Dec-10 MP added priority boost for read and write threads when
USE_READER_THREAD does I/O in separate threads. This helps
throughput since it allows these I/O bound threads to preempt
the main thread (which is executing simulated instructions).
09-Dec-10 MP allowed more flexible parsing of MAC address strings
09-Dec-10 MP Added support to determine if network address conflicts exist
07-Dec-10 MP Reworked DECnet self detection to the more general approach
of loopback self when any Physical Address is being set.
06-Dec-10 MP Added loopback processing support to pdp11_xu.c
06-Dec-10 MP Fixed loopback processing to correctly handle forward packets.
04-Dec-10 MP Changed eth_write to do nonblocking writes when
30-Nov-10 MP Fixed the fact that no broadcast packets were received by the DEUNA
29-Nov-10 MP Fixed interrupt dispatch issue which caused delivered packets
(in and out) to sometimes not interrupt the CPU after processing.
17-Jun-10 MP Fixed bug in the AUTODIN II hash filtering.
14-Jun-10 MP Added support for integrated Tap networking interfaces on BSD
13-Jun-10 MP Added support for integrated Tap networking interfaces on Linux
31-May-10 MP Added support for more TOE (TCP Offload Engine) features for IPv4
network traffic from the host and/or from hosts on the LAN. These
new TOE features are: LSO (Large Send Offload) and Jumbo packet
fragmentation support. These features allow a simulated network
device to support traffic when a host leverages a NIC's Large
Send Offload capabilities to fragment and/or segment outgoing
network traffic. Additionally a simulated network device can
reasonably exist on a LAN which is configured to use Jumbo frames.
21-May-10 MP Added functionality to fix up IP header checksums to accommodate
packets from a host with a NIC which has TOE (TCP Offload Engine)
enabled which is expected to implement the checksum computations
in hardware. Since we catch packets before they arrive at the
NIC the expected checksum insertions haven't been performed yet.
This processing is only done for packets sent from the host to
the guest we're supporting. In general this will be a relatively
small number of packets so it is done for all IP frame packets
coming from the host to the guest. In order to make the
determination of packets specifically arriving from the host we
need to know the hardware MAC address of the host NIC. Currently
determining a NIC's MAC address is relatively easy on Windows.
The non-windows code works on linux and may work on other *nix
platforms either as is or with slight modifications. The code,
as implemented, only messes with this activity if the host
interface MAC address can be determined.
20-May-10 MP Added general support to deal with receiving packets smaller
than ETH_MIN_PACKET in length. These come from packets
looped back by some bridging mechanism and need to be padded
to the minimum frame size. A real NIC won't pass us any
packets like that. This fix belongs here since this layer
is responsible for interfacing to the physical layer
devices, AND it belongs here to get CRC processing right.
15-Aug-08 MP Fixed transmitted packets to have the correct source MAC address.
Fixed incorrect address filter setting calling eth_filter().
07-Mar-08 MP Fixed the SCP visible SA registers to always display the
ROM MAC address, even after it is changed by SET XQ MAC=.
07-Mar-08 MP Added changes so that the Console DELQA diagnostic (>>>TEST 82)
will succeed.
03-Mar-08 MP Added DELQA-T (aka DELQA Plus) device emulation support.
06-Feb-08 MP Added dropped frame statistics to record when the receiver discards
received packets due to the receiver being disabled, or due to the
XQ device's packet receive queue being full.
Fixed bug in receive processing when we're not polling. This could
cause receive processing to never be activated again if we don't
read all available packets via eth_read each time we get the
31-Jan-08 MP Added the ability to Coalesce received packet interrupts. This
is enabled by SET XQ POLL=DELAY=nnn where nnn is a number of
microseconds to delay the triggering of an interrupt when a packet
is received.
29-Jan-08 MP Added SET XQ POLL=DISABLE (aka SET XQ POLL=0) to operate without
polling for packet read completion.
29-Jan-08 MP Changed the sanity and id timer mechanisms to use a separate timer
unit so that transmit and receive activities can be dealt with
by the normal xq_svc routine.
Dynamically determine the timer polling rate based on the
calibrated tmr_poll and clk_tps values of the simulator.
25-Jan-08 MP Enabled the SET XQ POLL to be meaningful if the simulator currently
doesn't support idling.
25-Jan-08 MP Changed xq_debug_setup to use sim_debug instead of printf so that
all debug output goes to the same place.
25-Jan-08 MP Restored the call to xq_svc after all successful calls to eth_write
to allow receive processing to happen before the next event
service time. This must have been inadvertently commented out
while other things were being tested.
23-Jan-08 MP Added debugging support to display packet headers and packet data
18-Jun-07 RMS Added UNIT_IDLE flag
29-Oct-06 RMS Synced poll and clock
27-Jan-06 RMS Fixed unaligned accesses in XQB (found by Doug Carman)
07-Jan-06 RMS Fixed unaligned access bugs (found by Doug Carman)
07-Sep-05 DTH Removed unused variable
16-Aug-05 RMS Fixed C++ declaration and cast problems
05-Mar-08 MP Added optional multicast filtering support for doing
LANCE style AUTODIN II based hashed filtering.
07-Feb-08 MP Added eth_show_dev to display Ethernet state
Changed the return value from eth_read to return whether
or not a packet was read. No existing callers used or
checked constant return value that previously was being
29-Jan-08 MP Added eth_set_async to provide a mechanism (when
USE_READER_THREAD is enabled) to allow packet reception
to dynamically update the simulator event queue and
potentially avoid polling for I/O. This provides a minimal
overhead (no polling) maximal responsiveness for network
29-Jan-08 MP Properly sequenced activities in eth_close to avoid a race
condition when USE_READER_THREAD is enabled.
25-Jan-08 MP Changed the following when USE_READER_THREAD is enabled:
- Fixed bug when the simulated device doesn't need crc
in packet data which is read.
- Added call to pcap_setmintocopy to minimize packet
delivery latencies.
- Added ethq_destroy and used it to avoid a memory leak in
- Properly cleaned up pthread mutexes in eth_close.
Migrated to using sim_os_ms_sleep for a delay instead of
a call to select().
Fixed the bpf filter used when no traffic is to be matched.
Reworked eth_add_packet_crc32 implementation to avoid an
extra buffer copy while reading packets.
Fixed up #ifdef's relating to USE_SHARED so that setting
USE_SHARED or USE_NETWORK will build a working network
23-Jan-08 MP Reworked eth_packet_trace and eth_packet_trace_ex to allow
only output Ethernet header+crc and provide a mechanism for
the simulated device to display full packet data debugging.
17-May-07 DTH Fixed non-Ethernet device removal loop (from Naoki Hamada)
15-May-07 DTH Added dynamic loading of wpcap.dll;
Corrected exceed max index bug in ethX lookup
04-May-07 DTH Corrected failure to look up Ethernet device names in
the registry on Windows XP x64
10-Jul-06 RMS Fixed linux conditionalization (from Chaskiel Grundman)
02-Jun-06 JDB Fixed compiler warning for incompatible sscanf parameter
15-Dec-05 DTH Patched eth_host_devices [remove non-Ethernet devices]
(from Mark Pizzolato and Galen Tackett, 08-Jun-05)
Patched eth_open [tun fix](from Antal Ritter, 06-Oct-05)
30-Nov-05 DTH Added option to regenerate CRC on received packets; some
Ethernet devices need to pass it on to the simulation, and by
the time libpcap/winpcap gets the packet, the host OS network
layer has already stripped CRC out of the packet
01-Dec-04 DTH Added Windows user-defined adapter names (from Timothe Litt)
19-Mar-04 Release:
1. Genericized Sim_Ether code, reduced #ifdefs (David Hittner)
2. Further refinement of sim_ether, qualified more platforms (Mark Pizzolato)
3. Added XU module (David Hittner)
4. Corrected XQ interrupt signaling for PDP11s (David Hittner)
5. Added inline debugging support (David Hittner)
26-Nov-03 Release:
1. Added VMS support to Sim_Ether; created pcap-vms port (Anders Ahgren)
2. Added DECNET duplicate detection for Windows (Mark Pizzolato)
3. Added BPF filtering to increase efficiency (Mark Pizzolato)
4. Corrected XQ Runt processing (Mark Pizzolato)
5. Corrected XQ Software Reset (Mark Pizzolato)
6. Corrected XQ Multicast/Promiscuous mode setting/resetting (Mark Pizzolato)
7. Added Universal TUN/TAP support (Mark Pizzolato)
8. Added FreeBSD support (Edward Brocklesby)
9. Corrected interrupts on XQB device (David Hittner)
05-Jun-03 Release:
1. Added SET/SHOW XQ STATS (David Hittner)
2. Added SHOW XQ FILTERS (David Hittner)
3. Added ability to split rcv packets into multiple buffers (David Hittner)
4. Added explicit runt & giant packet processing (David Hittner)
30-May-03 Release:
1. Corrected bug in xq_setmac introduced in v3.0 (multiple people)
2. Made XQ rcv buffer allocation dynamic to reduce scp size (David Hittner)
3. Optimized some structs, removed legacy variables (Mark Pizzolato)
4. Changed #ifdef WIN32 to _WIN32 for consistency (Mark Pizzolato)
06-May-03 Release:
1. Added second XQ controller (David Hittner)
2. Added SIMH v3.0 compatibility (David Hittner)
3. Removed SET ADDRESS functionality (David Hittner)
10-Apr-03 Release:
1. Added preliminary support for RSTS/E (David Hittner)
2. Added PDP-11 bootrom load via CSR flags (David Hittner)
3. Support for SPARC linux (Mark Pizzolato)
11-Mar-03 Release:
1. Added support for RT-11 TCP/IP
2. Corrected interrupts (thanks to Tom Evans and Bob Supnik)
3. Moved change log to the bottom of the readme file, cleaned up document
16-Jan-03 Release:
1. Added VMScluster support (thanks to Mark Pizzolato)
2. Verified VAX remote boot functionality (>>>B XQA0)
3. Added major performance enhancements (thanks to Mark Pizzolato again)
4. Changed _DEBUG tracers to XQ_DEBUG and ETH_DEBUG
5. Added local packet processing
6. Added system id broadcast
08-Nov-02 Release:
1. Added USE_NETWORK conditional to Sim_Ether
2. Fixed behavior of SHOW XQ ETH if no devices exist
3. Added OpenBSD support to Sim_Ether (courtesy of Federico Schwindt)
4. Added ethX detection simplification (from Megan Gentry)