/[gxemul]/trunk/doc/networking.html
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20070616	Implementing the MIPS32/64 revision 2 "ror" instruction.
20070617	Adding a struct for each physpage which keeps track of which
		ranges within that page (base offset, length) that are
		continuously translatable. When running with native code
		generation enabled (-b), a range is added after each read-
		ahead loop.
		Experimenting with using the physical program counter sample
		data (implemented 20070608) together with the "translatable
		range" information, to figure out which physical address ranges
		would be worth translating to native code (if the number of
		samples falling within a range is above a certain threshold).
20070618	Adding automagic building of .index comment files for
		src/file/, src/promemul/, src src/useremul/ as well.
		Adding a "has been translated" bit to the ranges, so that only
		not-yet-translated ranges will be sampled.
20070619	Moving src/cpu.c and src/memory_rw.c into src/cpus/,
		src/device.c into src/devices/, and src/machine.c into
		src/machines/.
		Creating a skeleton cc/ld native backend module; beginning on
		the function which will detect cc command line, etc.
20070620	Continuing on the native code generation infrastructure.
20070621	Moving src/x11.c and src/console.c into a new src/console/
		subdir (for everything that is console or framebuffer related).
		Moving src/symbol*.c into a new src/symbol/, which should
		contain anything that is symbol handling related.
20070624	Making the program counter sampling threshold a "settings
		variable" (sampling_threshold), i.e. it can now be changed
		during runtime.
		Switching the RELEASE notes format from plain text to HTML.
		If the TMPDIR environment variable is set, it is used instead
		of "/tmp" for temporary files.
		Continuing on the cc/ld backend: simple .c code is generated,
		the compiler and linker are called, etc.
		Adding detection of host architecture to the configure script
		(again), and adding icache invalidation support (only
		implemented for Alpha hosts so far).
20070625	Simplifying the program counter sampling mechanism.
20070626	Removing the cc/ld native code generation stuff, program
		counter sampling, etc; it would not have worked well in the
		general case.
20070627	Removing everything related to native code generation.
20070629	Removing the (practically unusable) support for multiple
		emulations. (The single emulation allowed now still supports
		multiple simultaneous machines, as before.)
		Beginning on PCCTWO and M88K interrupts.
20070723	Adding a dummy skeleton for emulation of M32R processors.
20070901	Fixing a warning found by "gcc version 4.3.0 20070817
		(experimental)" on amd64.
20070905	Removing some more traces of the old "multiple emulations"
		code.
		Also looking in /usr/local/include and /usr/local/lib for
		X11 libs, when running configure.
20070909	Minor updates to the guest OS install instructions, in
		preparation for the NetBSD 4.0 release.
20070918	More testing of NetBSD 4.0 RC1.
1 dpavlin 32 <html><head><title>Gavare's eXperimental Emulator:&nbsp;&nbsp;&nbsp;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 dpavlin 44 <b>GXemul:</b></font>&nbsp;&nbsp;
8 dpavlin 32 <font color="#000000" size="6"><b>Networking</b>
9     </font></td></tr></table></td></tr></table><p>
10    
11     <!--
12    
13 dpavlin 44 $Id: networking.html,v 1.7 2007/06/23 16:59:35 debug Exp $
14 dpavlin 32
15 dpavlin 34 Copyright (C) 2003-2007 Anders Gavare. All rights reserved.
16 dpavlin 32
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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 dpavlin 42 <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 dpavlin 32 <ul>
102 dpavlin 42 <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 dpavlin 32 <li><tt><b>ether</b></tt>, the "fake" experimental ethernet device
105     (documented <a href="experiments.html#expdevices_ether">here</a>)
106 dpavlin 44 <li><tt><b>le</b></tt>, <a href="http://en.wikipedia.org/wiki/TURBOchannel">Turbochannel</a>
107     Lance Ethernet, as used in DECstation 5000/200 ("3max")
108 dpavlin 32 <li><tt><b>mec</b></tt>, the SGI O2's ethernet controller
109     </ul>
110    
111 dpavlin 42 <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 dpavlin 32
116 dpavlin 42 <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 dpavlin 32
120    
121    
122    
123    
124 dpavlin 42
125    
126 dpavlin 32 <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">&nbsp;</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">&nbsp;</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">&nbsp;</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    
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