| 1 |
<html><head><title>Gavare's eXperimental Emulator: Networking</title> |
| 2 |
<meta name="robots" content="noarchive,nofollow,noindex"></head> |
| 3 |
<body bgcolor="#f8f8f8" text="#000000" link="#4040f0" vlink="#404040" alink="#ff0000"> |
| 4 |
<table border=0 width=100% bgcolor="#d0d0d0"><tr> |
| 5 |
<td width=100% align=center valign=center><table border=0 width=100%><tr> |
| 6 |
<td align="left" valign=center bgcolor="#d0efff"><font color="#6060e0" size="6"> |
| 7 |
<b>Gavare's eXperimental Emulator:</b></font><br> |
| 8 |
<font color="#000000" size="6"><b>Networking</b> |
| 9 |
</font></td></tr></table></td></tr></table><p> |
| 10 |
|
| 11 |
<!-- |
| 12 |
|
| 13 |
$Id: networking.html,v 1.5 2007/05/05 06:42:50 debug Exp $ |
| 14 |
|
| 15 |
Copyright (C) 2003-2007 Anders Gavare. All rights reserved. |
| 16 |
|
| 17 |
Redistribution and use in source and binary forms, with or without |
| 18 |
modification, are permitted provided that the following conditions are met: |
| 19 |
|
| 20 |
1. Redistributions of source code must retain the above copyright |
| 21 |
notice, this list of conditions and the following disclaimer. |
| 22 |
2. Redistributions in binary form must reproduce the above copyright |
| 23 |
notice, this list of conditions and the following disclaimer in the |
| 24 |
documentation and/or other materials provided with the distribution. |
| 25 |
3. The name of the author may not be used to endorse or promote products |
| 26 |
derived from this software without specific prior written permission. |
| 27 |
|
| 28 |
THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND |
| 29 |
ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
| 30 |
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
| 31 |
ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE |
| 32 |
FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
| 33 |
DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
| 34 |
OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
| 35 |
HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
| 36 |
LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
| 37 |
OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
| 38 |
SUCH DAMAGE. |
| 39 |
|
| 40 |
--> |
| 41 |
|
| 42 |
|
| 43 |
<a href="./">Back to the index</a> |
| 44 |
|
| 45 |
<p><br> |
| 46 |
<h2>Networking</h2> |
| 47 |
|
| 48 |
<p> |
| 49 |
<ul> |
| 50 |
<li><a href="#intro">Introduction</a> |
| 51 |
<li><a href="#multihost">Network across multiple hosts</a> |
| 52 |
<li><a href="#direct_example_1">Direct-access example 1: udp_snoop</a> |
| 53 |
</ul> |
| 54 |
|
| 55 |
|
| 56 |
|
| 57 |
|
| 58 |
|
| 59 |
|
| 60 |
|
| 61 |
<p><br> |
| 62 |
<a name="intro"></a> |
| 63 |
<h3>Introduction:</h3> |
| 64 |
|
| 65 |
GXemul's current networking layer supports two modes: |
| 66 |
|
| 67 |
<p><ol> |
| 68 |
<li>A NAT-like layer, which allows guest OSes to access the outside |
| 69 |
internet world (IPv4 only, so far). When only one machine is being |
| 70 |
emulated, the following default values apply to the guest OS:<pre> |
| 71 |
IPv4 address: 10.0.0.1 |
| 72 |
Netmask: 255.0.0.0 |
| 73 |
Gateway / default route: 10.0.0.254 |
| 74 |
Nameserver: 10.0.0.254 |
| 75 |
</pre>To the outside world, it will seem as if the host is doing all the |
| 76 |
networking, since the emulator is just a normal user process |
| 77 |
on the host. |
| 78 |
<p> |
| 79 |
<li>A direct-access layer, allowing external tools to read/write raw |
| 80 |
ethernet packages from/to the emulator. |
| 81 |
</ol> |
| 82 |
|
| 83 |
<p><i>NOTE:</i> Both these modes have problems. The NAT-like layer is very |
| 84 |
"hackish" and was only meant as a proof-of-concept, to see if networking |
| 85 |
like this would work with e.g. NetBSD as a guest OS. (If you are |
| 86 |
interested in the technical details, and the reasons why NAT networking is |
| 87 |
implemented this way, you might want to read the <a |
| 88 |
href="technical.html#net"> networking section in the technical |
| 89 |
documentation</a>.) Because of the obvious limitations with the NAT |
| 90 |
approach, I have also included support for direct packet access, but this |
| 91 |
is not designed for security or anything like that. |
| 92 |
|
| 93 |
<p><font color="#ff0000">Use the networking features at your own risk. |
| 94 |
</font> |
| 95 |
|
| 96 |
|
| 97 |
<p>The emulated machine must have a NIC (network interface card). Not all |
| 98 |
machines have this. At the moment, the following NICs are more or less |
| 99 |
working: |
| 100 |
|
| 101 |
<ul> |
| 102 |
<li><tt><b>dec21143</b></tt>, Digital's 21143 PCI NIC (known as <tt>dc</tt> |
| 103 |
in OpenBSD, or <tt>tlp</tt> in NetBSD) |
| 104 |
<li><tt><b>ether</b></tt>, the "fake" experimental ethernet device |
| 105 |
(documented <a href="experiments.html#expdevices_ether">here</a>) |
| 106 |
<li><tt><b>le</b></tt>, Turbochannel Lance Ethernet, as used in |
| 107 |
DECstation 5000/200 ("3max") |
| 108 |
<li><tt><b>mec</b></tt>, the SGI O2's ethernet controller |
| 109 |
</ul> |
| 110 |
|
| 111 |
<p>It is not possible to simply attach any of the supported NICs into any |
| 112 |
of the supported emulated machines. Some machines, for example, have a |
| 113 |
specific NIC in them, others may have a PCI bus where a PCI NIC can be |
| 114 |
used. This is very much machine-dependent. |
| 115 |
|
| 116 |
<p>If you are impatient, and simply want to try out networking in GXemul, |
| 117 |
I would recommend trying out an ftp install of <a |
| 118 |
href="guestoses.html#netbsdpmaxinstall">NetBSD/pmax</a>. |
| 119 |
|
| 120 |
|
| 121 |
|
| 122 |
|
| 123 |
|
| 124 |
|
| 125 |
|
| 126 |
<p><br> |
| 127 |
<a name="multihost"></a> |
| 128 |
<h3>Network across multiple hosts:</h3> |
| 129 |
|
| 130 |
<p>The way to emulate a network of multiple emulated machines, whether |
| 131 |
they are actually running on the same physical host, or on multiple hosts, |
| 132 |
is to use <a href="configfiles.html">configuration files</a>, and the |
| 133 |
"direct-access" method of networking. |
| 134 |
|
| 135 |
<p>Although it <i>is</i> possible to have more than one machine per |
| 136 |
configuration file, I strongly recommend against it. Please use one |
| 137 |
configuration file for one emulated machine. |
| 138 |
|
| 139 |
<p>Here is a simple example: |
| 140 |
|
| 141 |
<p><table border="0" width="100%"><tr><td width="40"> </td> |
| 142 |
<td><pre> |
| 143 |
<font color="#2020cf">! Configuration file for a |
| 144 |
! "client" machine, netbooting |
| 145 |
! of another machine.</font> |
| 146 |
|
| 147 |
<b>net(</b> |
| 148 |
<b>local_port(15000)</b> |
| 149 |
<b>add_remote(<font color="#ff003f">"localhost:15001"</font>)</b> |
| 150 |
<b>)</b> |
| 151 |
<b>machine(</b> |
| 152 |
<b>name(<font color="#ff003f">"client machine"</font>)</b> |
| 153 |
<b>serial_nr(1)</b> <font color="#2020cf">! 10.0.0.1</font> |
| 154 |
|
| 155 |
<b>type(<font color="#ff003f">"sgi"</font>)</b> |
| 156 |
<b>subtype(<font color="#ff003f">"o2"</font>)</b> |
| 157 |
<b>load(<font color="#ff003f">"netbsd-GENERIC32_IP3x.gz"</font>)</b> |
| 158 |
<b>)</b> |
| 159 |
</pre></td><td width="20"> </td><td><pre> |
| 160 |
<font color="#2020cf">! Configuration file for the |
| 161 |
! "server" machine.</font> |
| 162 |
|
| 163 |
<b>net(</b> |
| 164 |
<b>local_port(15001)</b> |
| 165 |
<b>add_remote(<font color="#ff003f">"localhost:15000"</font>)</b> |
| 166 |
<b>)</b> |
| 167 |
<b>machine(</b> |
| 168 |
<b>name(<font color="#ff003f">"nfs server"</font>)</b> |
| 169 |
<b>serial_nr(2)</b> <font color="#2020cf">! 10.0.0.2</font> |
| 170 |
|
| 171 |
<b>type(<font color="#ff003f">"dec"</font>)</b> |
| 172 |
<b>subtype(<font color="#ff003f">"3max"</font>)</b> |
| 173 |
<b>disk(<font color="#ff003f">"nbsd_pmax.img"</font>)</b> |
| 174 |
<b>)</b> |
| 175 |
</pre></td><td width="20"> </td></tr></table> |
| 176 |
|
| 177 |
<p>This example creates a network using the default settings (10.0.0.0/8), |
| 178 |
but it also uses the direct-access networking mode to allow the network |
| 179 |
to be connected to other emulator instances. <tt>local_port(15000)</tt> |
| 180 |
means that anything coming in to UDP port 15000 on the host is added to |
| 181 |
the network. All ethernet packets on the network are also sent out to all |
| 182 |
other connected machines (those added with <tt>add_remote()</tt>). |
| 183 |
|
| 184 |
<p>As you can see in the example, this is a configuration file for |
| 185 |
netbooting a NetBSD/sgimips diskless machine, with a NetBSD/pmax machine |
| 186 |
acting as the nfs server. Note that the nfs server has ports 15000 and |
| 187 |
15001 reversed, compared to the client! |
| 188 |
|
| 189 |
<p>"<tt>localhost</tt>" can be changed to the Internet hostname of a |
| 190 |
remote machine, to run the simulation across a physical network. |
| 191 |
|
| 192 |
<p><font color="#ff0000"><b>NOTE:</b> There is no error checking or |
| 193 |
security checking of any kind. All UDP packets arriving at the input port |
| 194 |
are added to the emulated ethernet. This is not very good of course; use |
| 195 |
this feature at your own risk.</font> |
| 196 |
|
| 197 |
|
| 198 |
|
| 199 |
|
| 200 |
|
| 201 |
<p><br> |
| 202 |
<a name="direct_example_1"></a> |
| 203 |
<h3>Direct-access example 1: udp_snoop:</h3> |
| 204 |
|
| 205 |
The most basic example of how the simple direct-access system works is a small |
| 206 |
program in the <tt>experiments/</tt> directory, <tt>udp_snoop</tt>, which simply |
| 207 |
dumps incoming UDP packets to the terminal, in hex and ASCII. |
| 208 |
|
| 209 |
<p>The easiest way to test the example is to download a <a href="ftp://ftp.netbsd.org/pub/NetBSD/NetBSD-3.1/pmax/binary/kernel/netbsd-INSTALL.gz"> |
| 210 |
NetBSD/pmax INSTALL kernel</a>, and start the emulator with a configuration file |
| 211 |
looking something like this: |
| 212 |
|
| 213 |
<pre> |
| 214 |
net( |
| 215 |
add_remote("localhost:12300") |
| 216 |
) |
| 217 |
|
| 218 |
machine( |
| 219 |
subtype(3max) |
| 220 |
load("netbsd-INSTALL.gz") |
| 221 |
) |
| 222 |
</pre> |
| 223 |
|
| 224 |
<p>In addition to the machine section, you can see that there is also a |
| 225 |
<tt>net()</tt> section. It defaults to emulating a 10.0.0.0/8 IPv4 NATed |
| 226 |
network, but there is also an additional "raw output", to UDP port 12300. |
| 227 |
|
| 228 |
<p>Now, do the following: |
| 229 |
<ul> |
| 230 |
<li>Start the emulator with the configuration file, i.e. |
| 231 |
<tt><b>gxemul @testconfig</b></tt>. |
| 232 |
<li>Start <tt><b>udp_snoop 12300</b></tt> in another terminal. |
| 233 |
<li>Inside emulated NetBSD/pmax, type <tt><b>ifconfig le0 10.0.0.1</b></tt>. |
| 234 |
</ul> |
| 235 |
|
| 236 |
<p>This should be enough to see broadcast messages from the guest OS which |
| 237 |
are not directed to the gateway. It might look like this: |
| 238 |
|
| 239 |
<pre> |
| 240 |
$ ./udp_snoop 12300 |
| 241 |
ff ff ff ff ff ff 10 20 30 00 00 10 08 06 00 01 ....... 0....... |
| 242 |
08 00 06 04 00 01 10 20 30 00 00 10 0a 00 00 02 ....... 0....... |
| 243 |
00 00 00 00 00 00 0a 00 00 02 00 00 00 00 00 00 ................ |
| 244 |
00 00 00 00 00 00 00 00 00 00 00 00 ............ |
| 245 |
|
| 246 |
33 33 ff 00 00 10 10 20 30 00 00 10 86 dd 60 00 33..... 0.....`. |
| 247 |
00 00 00 20 00 01 00 00 00 00 00 00 00 00 00 00 ... ............ |
| 248 |
00 00 00 00 00 00 ff 02 00 00 00 00 00 00 00 00 ................ |
| 249 |
00 01 ff 00 00 10 3a 00 01 00 05 02 00 00 83 00 ......:......... |
| 250 |
80 83 00 00 00 00 ff 02 00 00 00 00 00 00 00 00 ................ |
| 251 |
00 01 ff 00 00 10 ...... |
| 252 |
... |
| 253 |
</pre> |
| 254 |
|
| 255 |
|
| 256 |
|
| 257 |
|
| 258 |
</p> |
| 259 |
|
| 260 |
</body> |
| 261 |
</html> |
| 262 |
|
| 263 |
|
Parent Directory
| 
Revision Log