Guides:MAME - Networking

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(Ether)net Networking in MAME

Support was added back in ~2012 but the documentation is fragmented.

Note alot of older posts say to compile with USE_NETWORK=1, this is no longer required as it became the default in 0.156

Very basically you will

  • give the MAME machine a static ip internally,

on the host

  • tweak some ipv4 network behavior
  • create a basic tap device
  • route traffic out the hosts eth int

MAME only looks at the /dev/net/tun device currently (0.229) with a specific naming convention so it wont support macvtap devices etc atm.

The naming convention (commit 2ca5f3a) of the tap device seems to be important, otherwise MAME doesn't seem to know what to use. Its not a parameter we can pass into the machine, this probably limits the possiblities of building networks between MAME machines

/src/osd/modules/netdev/taptun.cpp
91: sprintf(ifr.ifr_name, "tap-mess-%d-0", getuid());


List MAME Networks

mame -listnetwork will display available devices as per below

$ ./mame -listnetwork
Available network adapters:
    TAP/TUN Device


tap device setup

Manual setup

  1. Allow forwarded traffic, and proxied arp requests
  2. Create a tap device and route traffic across you host ethernet
  3. confirm you have read access to the /dev/net/tun device
  # echo 1 > /proc/sys/net/ipv4/ip_forward
  # echo 1 > /proc/sys/net/ipv4/conf/all/proxy_arp
  # chmod 666 /dev/net/tun

  $ MAMESTATIC=192.168.0.102
  $ HOSTIP=192.168.0.200
  $ TAP=tap-mess-<uid>-0
  $ USERNAME=$(whoami)
  $ sudo ip tuntap add dev $TAP mode tap user $USERNAME
  $ sudo ip link set $TAP up arp on
  $ sudo ip addr replace dev $TAP $HOSTIP/32
  $ sudo ip route replace $MAMESTATIC via $HOSTIP dev $TAP 

  $ ip link show $TAP
  $ ip route

MAME Script

MAME has a script in the git repo /src/osd/sdl/taputil.sh

The format to execute this is

sudo taputil.sh <mame user> <mame machine ip> <host machine ip>

NOTE: be mindful of this script, it will not honor existing tap perms nor kernel settings see #7877

MAME Setup

In the in-game UI

  • open the Network Devices menu and select "TAP/TUN Device"
  • Confirm the IRQ under machine configuration is correct
IRQs

Just a note on my config,

  • ISA1 svga_s1,
  • ISA2, sblaster_16 (IRQ5)
  • ISA4 ne2000.

The IRQ used by the ne2000 adapter would only work on IRQ2/9

DOS Setup

Load the ne2000 drivers from in autoexec.bat, try auto discovery first

c:\PATH\TO\NE2000.COM 0x60

A decent test suite of tools while getting setup is the mTCP project, refer to their doco to setup the config etc. but remove LEASE_TIME from the ip settings to set a static ip for use with the applications otherwise the applications will throw a lease expired warning and exit

Drivers/Software

References