OpenSimulator - User contributions [en]

Build Instructions

2009-01-19T11:58:07Z

MWr: /* Running */

[[Category:Users]]
This page covers building OpenSim from source code on multiple platforms. Please help us keep this page up to date as the project progresses.

==Download from SVN==
Check out the [[Download]] Section

==MS Windows==

OpenSim requires either the .Net framework version 2.0, or the latest Mono. It supports the following compilers:
* [http://msdn2.microsoft.com/en-us/express/aa700756.aspx Microsoft Visual C# Express Edition] (note: not Visual C++)
* [http://www.mono-project.com/ mono]

Note for people who just downloaded the sources from http://dist.opensimulator.org/ (the "Downloads" link on the left) be advised that some important things are missing (like MySQL template scripts). For such features, you must download using svn!

Additional note: any Microsoft C# Express edition should work (2005 or 2008)

Additional note: It is possible to develope on Windows Vista 64 bits with the following tweaks:
# Select OpenSim project properties from solution and choose platform to be x86. Rebuild solution.
# Select OpenSim.exe properties under solution bin folder and choose windows xp sp 2 compatibility mode + run as administrator.

=== Building ===

* In the top-level directory, run the '<tt>runprebuild.bat</tt>' file. This will create a VS2005 solution file, a nant build file and a '<tt>compile.bat</tt>' file.
* If you prefer VS2008, run the '<tt>runprebuild2008.bat</tt>' instead.

* Open the resulting sln file with visual studio and build it there, or
* Run the '<tt>compile.bat</tt>' file. This will build the executable using MSBuild.
* if you prefer to use nant, run nant in the same top-level directory. This will build the executables.

If you don't care about physics (walking on prims, etc), ignore the rest of this section.

=== Running ===

Recent versions of OpenSim come without an <tt>OpenSim.ini</tt> file. Copy the <tt>OpenSim.ini.example</tt> file to <tt>OpenSim.ini</tt> before making any changes.

Double-click on the <tt>OpenSim.exe</tt> executable file in the <tt>bin</tt> directory. This will start up OpenSim in standalone mode.

The debugger in VS2005 C# may be used to step through the code. For those that use a Cygwin shell, you may find that one or more dll's have permissions that cause problems running. Most find that a "<tt>chmod 777 *</tt>" from the <tt>bin</tt> directory solves this.

Physics can be invoked by adding the appropriate line to the [Startup] section of <tt>OpenSim.ini</tt>. For ODE, that would be:

physics = OpenDynamicsEngine

You can also add a command line option to a shortcut, or run from a command prompt with:

-physics=OpenDynamicsEngine

'''''Windows Vista'''''

Some people have reported that to run on Windows Vista, you must first disable Windows Firewall. Under the new "Start" button of Vista, select "Control panel". Then double-click "Windows Firewall". In the window that pops up, on the left column, select "Turn Windows Firewall on or off". You will have to give permission for this to run, then select the option "Off (not recommended)". Click "OK" and exit from the Windows Firewall window.

If you have McAfee SecurityCenter, see the description below.

Once all the security features are disabled, right click on <tt>OpenSim.exe</tt> and select "Run as administrator". This will pop up a window asking permission, select "Allow". Your OpenSim server should run in a DOS-like window and accept connections.

'''''McAfee Security'''''

McAfee Security does not allow applications to listen on ports not explicitly specified. You have two options: 1) disable firewall protection all together, 2) enable <tt>OpenSim.exe</tt> to be able to open ports.

''Disable firewall''

Open McAfee SecurityCenter. Select "Internet & Network". In the lower left corner is a small link to "Configure...". Select this. In the right side of the window, select the bar that says "Firewall protection is enabled". Here you can select "Off".

''Enable <tt>OpenSim.exe</tt> to open ports''

Open McAfee SecurityCenter. Select "Internet & Network". In the lower left corner is a small link to "Configure...". Select this. In the right side of the window, select the bar that says "Firewall protection is enabled". Select the "Advanced..." button. This will pop up a new window.

In the new window, on the left side, select "Program Permissions." In the middle on the right side of the window, select the "Add Allowed Program" button. Use the browser that pops up to find the OpenSim executable and select it.

Finally, select "OK" and exit the McAfee SecurityCenter window.

==Linux/Mac OS X/FreeBSD==

The easiest plaform to get running on the Linux side is Ubuntu 8.10, 32bit. This is what most of the developers running Linux use. If you are looking for the quick path, start there.

=== Ubuntu 8.04 / 8.10 ===

For Ubuntu users on older distributions (7.10, 8.04, etc.) '''you need''' to upgrade your mono to 1.9.1.

You can use the built in packages for mono. However, for better performance, you may want to [http://xyzzyxyzzy.net/2008/05/08/updated-mono-build-script-for-hardy-heron-and-mono-191/ upgrade mono to 1.9.1] ([http://tempvariable.blogspot.com/2008/04/installing-mono-191-on-ubuntu-804-hardy.html Other simple method])

sudo apt-get install subversion nant mono-gmcs libmono-microsoft8.0-cil \
libmono-system-runtime2.0-cil libgdiplus libmono-i18n2.0-cil libmono-oracle2.0-cil ruby
svn co http://opensimulator.org/svn/opensim/trunk opensim
cd opensim
./runprebuild.sh
nant

To upgrade the Mono version to the latest stable build Mono 2.0.1, read this page [[Build Instructions/Ubuntu-Mono-2.0.1 | Ubuntu on Mono 2.0.1]]

=== openSUSE 10.3 and 11 ===

Install an openSUSE 11 or 10.3 with its default options, add the online repositories
when finished installing do an online update with all the latest packages.

In yast install these packages, for running Opensim in standalone mode.
(there is a slight diffrence between 10.3 and 11 but following should be same)
subversion
nant
mono-jscript
- check that mono-core is installed

If you just want to use SQLite then jump to last section
within this post.

* Optional mysql - for Opensim running in Grid mode:
Install these mysql packages via yast
mysql
mysql-client
mysql-administrator
mysql-gui-tools
mysql-query-browser

Before building create the mysql database.
/etc/init.d/mysql start
mysql -u root -p -h localhost
(when asked for password just hit enter)

mysql> create database opensim;
mysql> quit

set the configuration in bin/mysql_connection.ini
Or on later builds set the connection string inside bin/OpenSim.ini

Build after installation of above in bash terminal. i save it in /opt

su -
cd /opt
svn co http://opensimulator.org/svn/opensim/trunk opensim
cd opensim
./runprebuild.sh
nant

After this you should be able to continue on starting the diffrent Servers, look in the mysql-config section,or
just run your OpenSim as a Standalone. By - eagleFX

=== Mac OS X 10.5/10.4 ===
* OpenSim is now working on PowerPC Macs! Thanks to DrScofield and those who helped him. Current nightly builds for PowerPC are not working, not sure about Intel so use the 0.5 Build. OpenSim works on Intel Macs. I'm testing on PowerBook G4. Tested these step on 10.5, but not 10.4 but should work --[[User:Mokele|Mokele]] 22:36, 14 February 2008 (PST) (Works on iMac G5 with OS 10.4.11, including expanding to local grid mode. --[[User:Magnuz|Magnuz]] 2008-12-15 10:50 (CET))
* Install XCode Developers Tools from DVD/CD Installation Disk or download from http://developer.apple.com/. You have to create an Apple account to access the downloads if you don't have an Apple account.
* Install X11 for 10.4 from the Optional Install from the DVD/CD Installation Disk. X11 for 10.5 is installed by default.
* Install Mono 1.2.5 from http://ftp.novell.com/pub/mono/archive/1.2.5/macos-10-universal/5/MonoFramework-1.2.5_5.macos10.novell.universal.dmg (The more recent releases Mono 1.2.6, 1.9.1 and 2.0.1 do not appear to work with these installation instructions. --[[User:Magnuz|Magnuz]] 2008-12-14 15:56 (CET)) and in Terminal or X11 edit the .profile file and add the following line:
export PKG_CONFIG_PATH="/Library/Frameworks/Mono.framework/Versions/Current/lib/pkgconfig/:${PKG_CONFIG_PATH}"
* Compile OpenSim
svn co http://opensimulator.org/svn/opensim/tags/0.5.0-release opensim
cd opensim
./runprebuild.sh
nant

* Download and Compile libopenjpeg-libsl-2.1.2.0.dylib and libsecondlife.dll
* libopenjpeg-libsl-2.1.2.0.dylib:
svn co http://opensimulator.org/svn/opensim-libs/old/libsl1550 opensim-libs
cd opensim-libs/openjpeg-libsl
make -f Makefile.osx
cp libopenjpeg-libsl-2.1.2.0.dylib ../../bin
* Note: The Makefile that creates the libopenjpeg-libsl-2.1.2.0.so does not compile on PowerPC, but works properly on Intel Macs. Looks like a gcc issue with compile options. (It appears to work on iMac G5 with OS X 10.4.11. --[[User:Magnuz|Magnuz]] 2008-12-14 15:55 (CET))

* libsecondlife.dll: (for PowerPC Only, see details on this step [http://xyzzyxyzzy.net/2008/02/12/installing-opensim-on-powerpcor-of-eggs-and-virtual-worlds installing OpenSim on PowerPC…or: of eggs and virtual worlds])
cd .. (back into opensim-libs)
nant
cp bin/libsecondlife.dll ../bin

* Edit the libsecondlife.dll.config (PowerPC Only). Remove the cpu="x86" tag in the last dllmap line.

=== FreeBSD 6.2 ===
su
cd /usr/ports/devel/subversion/ && make install clean (you may also need to rebuild apr-svn if this step fails)
cd /usr/ports/lang/mono/ && make install clean
cd /usr/ports/devel/nant/ && make install clean
cd /usr/ports/databases/sqlite3/ && make install clean
cd /usr/ports/x11-toolkits/libgdiplus/ && make install clean
cd /opensim/installation/directory/
svn co http://opensimulator.org/svn/opensim/trunk opensim
cd opensim
./runprebuild.sh
nant

Note: [http://opensimulator.org/wiki/OpenSim:FAQ#System.DllNotFoundException:_..2Flibopenjpeg-libsl-2.1.2.0.so|Follow the instructions on the FAQ to fix the]
"System.DllNotFoundException: ./libopenjpeg-libsl-2.1.2.0.so" issue, but use "gmake" instead of "make"

For ODE Physics you must do the following:
cd /usr/ports/graphics/libGL/ && make install clean
cd /usr/ports/graphics/libGLU/ && make install clean
cd /opensim/installation/directory/
svn co http://opensimulator.org/svn/opensim-libs/trunk opensim-libs
cd opensim-libs/unmanaged/OpenDynamicsEngine2/
sh autogen.sh
./configure --enable-shared --enable-release --disable-demos
make
mv ./ode/src/.libs/libode.so /opensim/installation/directory/opensim/bin/

=== RedHat Enterprise Linux 4 ===
sudo vi /etc/yum.repos.d/mono.repo

[mono]
name=Mono for rhel-4-i386 (stable)
baseurl=http://ftp.novell.com/pub/mono/download-stable/rhel-4-i386/
enabled=1
gpgcheck=0

sudo yum install mono-complete monodoc-core nant
svn co svn co http://opensimulator.org/svn/opensim/trunk opensim
cd opensim
./runprebuild.sh
nant

=== RedHat Enterprise Linux 5 ===

The instructions below also work on other RedHat Linux flavors such as CentOS or maybe Fedora.

1. Put the [http://download.opensuse.org/repositories/Mono/RHEL_5/Mono.repo Mono.repo] file in the /etc/yum.repo.d/ directory:
$ sudo su -
$ cd /etc/yum.repos.d/
$ wget http://download.opensuse.org/repositories/Mono/RHEL_5/Mono.repo
Naturally use the most [http://download.opensuse.org/repositories/Mono up-to-date link for your distribution].

2. Install Mono and related tools with yum:
$ yum install mono nant mono-jscript mono-nunit
Make sure to use nunit-console2 to run your tests.

=== Fedora 5 ===
* I needed to build latest mono and nant from sources to build OpenSim successfully, the ones available in yum repository didn't work so I had to uninstall and build and configure the packages.

For detailed instructions go [http://ruakuu.blogspot.com/2008/06/installing-and-configuring-opensim-on.html here]

=== Debian 4 ===

The following packages and their dependencies are required to run OpenSim on a default Debian 4 netinstall:
* mono
* libmono-corlib2.0-cil
* libmono-sqlite2.0-cil
* libmono-system-web2.0-cil
* libmono-microsoft8.0-cil
* libmono-system-runtime2.0-cil
* libmono-oracle2.0-cil (new dependency since r7587)

Hint: Currently (Nov/28/2008) it is possible to use Debian etch, but you will need to add custom repositories for mono to work. However installing or upgrading to Lenny/Sid will enable you to use the standard debian repositories.

=== CentOS 5.2 32bit ===

For detailed instructions please see [[CentOS 5.2 Build Instructions]]

=== 64bit ===
Please note that only 32bit binaries are provided in the bin/ directory of subversion. If you want to use 64bit, you'll need to rebuild these shared objects. See [[Installing and running on x86-64]]

=== Physics (Open Dynamics Engine ODE) ===
As installed from svn, ODE will work on most 32 bit platforms. If you get an ODE-related crash, and/or a <i>libode.so not found</i> type of error, you will need to build libode from source.

Remove <tt>libode.so</tt> from the <tt>./bin</tt> folder. (Note that subsequent svn updates may replace it again; best fix is to copy your built <tt>libode.so</tt> to <tt>bin</tt>). Do NOT remove <tt>ode.net.dll</tt>! Download the latest source from:

svn co http://opensimulator.org/svn/opensim-libs/trunk/unmanaged/OpenDynamicsEngine

OpenSim requires a couple of patches on top of ODE which are not yet included upstream. When compiling, make sure to use the following configure options:

--with-trimesh=gimpact
--enable-shared

Make sure the configure script confirms these choices, and always compile with single precision (I believe that's the default). Try <code> make -k </code> if you get errors relating to drawstuff, test*, or openGL. <code> make install </code> should put <tt>libode.so</tt> in the proper place (usually <tt>/usr/local/lib</tt>), and it should be seen by opensim (<tt>ode.net.dll</tt>)

'''''Note:''' if OpenSim fails to launch with <tt>Exception: System.DllNotFoundException: ode</tt>, after compiling ODE, just copy <tt>libode.so</tt> from its usual place (probably <tt>/usr/local/lib/</tt>) to ./bin/, as per [http://metafuturing.net/index.php/OpenSim_Notebook_1 this suggestion]''

Setting up ODE for 64 Bits systems:

========================================================================
HOWTO on setting up and Install OpenSim on SLES10 - SP1 64Bit

1. I installed Mono 2.01, added this installation source in Yast2
This distro supports installing packages via YaST. Add the following installation source to YaST:
* http://ftp.novell.com/pub/mono/download-stable/SLE_10 [^]
For assistance with using repositories and installing packages with YaST, visit the Yast help page.

"nant" was installed also via this operation.

2. I installed subversion from http://software.opensuse.org/search [^]

SLES/SLED10 ->
subversion-1.5.2-34.2.x86_64.rpm

3. I downloaded and installed the lastest SVN version of opensim as usual (like a 32 bit system):
http://opensimulator.org/wiki/Build_Instructions [^]

4. I downloaded and installed the Open Dynamics Engine (ODE) to replace the 32 bit version of ODE with a 64 bit version.

I did that with the following linux commands:
(it is expected that you have all required Linux building tools installed):

# cd
# svn co http://opensimulator.org/svn/opensim-libs/trunk/unmanaged/OpenDynamicsEngine [^]
# cd OpenDynamicEngine
# chmod a+x ou/bootstrap
# sh autogen.sh

I installed/updated SLES10 with these rpm's for autogen.sh to run properly. http://software.opensuse.org/search [^]

SLES/SLED10 ->
- autoconf-2.61-168.1.x86_64.rpm
- automake-1.10.1-5.3.x86_64.rpm

# CFLAGS="-m64" ./configure --enable-shared
# make

I installed gtk2-devel via yast2, and all its dependancies, because make keept failing.

# cp ./ode/src/.libs/libode.so /opt/opensim/bin/

note:
in this directory it had made several versions of the "libode.so" because of running the previous commands several times
so i had to copy libode.so.1.0.0 to /opt/opensim/bin/libode.so

# vi ../opensim/bin/OpenSim.ini (change av_capsule_standup_tensor_linux to 1700000)

The 'chmod' command is required to fix permissions that are wrong.
The change in OpenSim.ini is required to avoid that avatars have bend legs and/or their feet are in the ground.
========================================================================

===Running===
Recent versions of OpenSim come without an <tt>OpenSim.ini</tt> file. Copy the <tt>OpenSim.ini.example</tt> file to <tt>OpenSim.ini</tt> before making any changes.
<code>
cd bin
mono OpenSim.exe
</code>

Note: if you are running a 32bit Server such as Ubuntu 8.0.4 you need the alternative launcher:

<code>
mono OpenSim.32BitLaunch.exe
</code>

* To invoke ODE, add the option:
-physics=OpenDynamicsEngine
to the <tt>mono OpenSim.exe</tt> line

or add <code> physics = OpenDynamicsEngine </code> to the [Startup] section of <tt>OpenSim.ini</tt>. Same deal for other physics engines, when available.

On mono 1.2.6, some distributions may see
Unhandled Exception: System.NotSupportedException: CodePage 1252 not supported
on startup when using mysql. This can be resolved by installing the package libmono-i18n2.0-cil (see http://bugs.mysql.com/bug.php?id=33938).

=== Additional Items ===

* [[GC_NO_EXPLICIT|GC NO EXPLICIT]] - Enable Large Heap in Mono, this has been known to help performance and stability

== Hardware selection guide ==

An often-asked question is "what kind of hardware do I need to successfully run OpenSim?" Unfortunately, the answer is "it depends". The number of regions hosted on a given machine, number of simultaneous avatars on those regions, number of prims, use of scripts, etc., all affect hardware requirements. So, to help you make a more informed selection, some examples of hardware used are listed in the [[Hardware_Selection_Guide|hardware selection guide]].

[[Category:Users]]

Hypergrid

2009-01-19T10:20:03Z

MWr: /* Hypergrid Lists */

==The OpenSim Hypergrid==

=== What is the hypergrid? ===


The hypergrid is an extension to opensim that allows you to link your opensim to other opensims on the internet, and that supports seamless agent transfers among those opensims. It can be used both in standalone mode and in grid mode. The hypergrid is effectively supporting the emergence of a Web of virtual worlds.

The basic idea for the hypergrid is that region/grid administrations can place hyperlinks on their map to hypergrided regions run by others. Once those hyperlinks are established, users interact with those regions in exactly the same way as they interact with local regions. Specifically, users can choose to teleport there. Once the user reaches the region behind the hyperlink, she is automatically interacting with a different virtual world without having to logout from the world where she came from, and while still having access to her inventory.

The hypergrid started as a GForge project, but it is now included in the standard distribution of OpenSim. To run your OpenSim instance in hypergrid mode, please see [[Hypergrid#Installing_and_Running_Hypergrid|Installing and Running]].

=== Virtual World Hyperlinks ===
[[image:hghyperlink.jpg|250px|thumb|A Virtual World Hyperlink]]

We're all familiar with hypertext links on the Web. But what is a virtual world hyperlink?

In the hypergrid model, we consider the 2D map of the virtual world as the equivalent of a web page. As such, a VW hyperlink is simply a region on that map.

The default model of opensim-based virtual worlds already supports this concept of hyperlink, to some extent. When you teleport from one region to another via the map, chances are you are migrating your agent into a different opensim server. This migration is a glorified "agent transfer" that also exists, in rudimentary form, on the web when hypertext links are followed. The default model, however, imposes two very strong constraints on these hyperlinks:
# The entire map of regions is controlled by a central service known as the grid service, whose job is to provide a uniform view of the world to all of its regions.
# The only agents that can be transferred are those pertaining to users known to another central service, the user service; if the incoming user is not on that service's database, the agent transfer doesn't go through.

The hypergrid simply removes these two constraints.

First, it allows individual opensim instances to add "neighbors" to their local map, shifting the control of the map down from the grid server to individual opensim instances (although hyperlinks can also be served by grid servers if grid admins so wish). In doing so, the world becomes a lot more interesting and varied. The map that you see in one opensim instance may be completely different from the map that you see after you teleport via an hyperlink. As an opensim administrator, you are free to define what other opensims you want to see on your map.

Second, it allows the transfer of agents pertaining to foreigner users, i.e. users who are registered elsewhere. Instead of assuming one central user service, the hypergrid assumes an arbitrarily large number of such services distributed all over the world. As such, when agents are transferred among hypergrided opensims, a lot more information is passed about the corresponding user. That information includes the collection of servers that the transferring user needs.

=== Usage Scenarios ===

The following are some usage scenarios. There isn't a clear separation between these scenarios, there's a large overlap between them. This is also not an exhaustive list. The purpose of these descriptions is to give you some starting ideas for how to use the hypergrid in practice. Please feel free to add other interesting scenarios to this list.

{| {{Prettytable}}
|-
|
[[image:topoA.jpg|400px|left]]
|
'''Personal Worlds'''

This first scenario pertains to standalone opensims. Normally, standalones are completely disconnected from the internet. However, when run in hypergrid mode, standalones become network-able. As such, you can run your own world in your own computer, and link your world to whoever you want. For example, you can link to your friends' hypergrided opensims and to hypergrid gateways in open grids such as OSGrid.

The great thing about this scenario is that all of your assets are stored on your computer, and not on somebody else's server. You can back them up using ordinary backend tools. The not so great thing about this scenario is that all of your assets are stored on your computer! If your disk goes berserk, you loose them. (so make sure you make external backups regularly)

|-
|
[[image:topoB.jpg|400px|left]]
|
'''Communities'''

This second scenario is about communities, broadly construed. The idea here is that a group of people come together to support a small community grid, i.e. a common world where shared activities take place. But at the same time, the members of the community maintain their own standalone worlds. The standalones link to the community grid, and the community grid may link back to the individual members' worlds and other places of interest.

The members' identities are probably the identities they have on their standalones, and their assets are also probably stored there. The assets present in the community regions, however, are stored on the grid asset server.

|-
|
[[image:topoC.jpg|400px|left]]
|
'''Grid Public Regions'''

Walled-gardens are here to stay, and they serve many useful purposes. There is a hybrid mode for the hypergrid that some walled-garden grid operators may be interested in supporting. In this hybrid mode, most opensim instances on the grid run in normal, wall-garden mode, so no foreign visitors are allowed there - technically it is impossible to reach them. However, a few opensim instances on that grid can run in hypergrid mode, so that foreign visitors are allowed. This way, there is a gateway for grid-local users and arbitrary visitors to meet. This is also a good strategy for attracting new users to the grid, since random users are able to visit those gateway regions without having to sign up for an account upfront.

This hybrid mode is very similar to what happens on the web. For example, anyone can visit Facebook's public pages without having to sign up for a Facebook account. However, only Facebook users can go further inside.

|-
|
[[image:topoD.jpg|400px|left]]
|
'''Level Games'''

The normal version of OpenSim enforces a common map for all the regions on a grid. The hypergrid removes that constraint. As such, it becomes easy to design VW games where the world looks different depending of where the player is.

|-
|}

== Security Concerns ==

There is a wide-spread assumption that open grids such as OSGrid and new forms of grids such as the hypergrid are inherently insecure, and that it will be impossible to develop a "goods-based" economy on top of them; only walled-gardens can be secured. This is both true and false. While it is true with the current state of things, open grids, whatever their form, can be made as secure as the web. The first step towards that is to define exactly what the security threats are, and how they affect (or not) open and closed grids. So, let's spell them out, and face them head-on. This will help put our feet on the ground so that we start developing appropriate solutions.

=== Malicious Clients ===

==== CopyBots ====

Everyone knows about the infamous [http://en.wikipedia.org/wiki/CopyBot CopyBot]. Using libraries such as [http://www.libsecondlife.org/wiki/Main_Page LibSL] (now known as OpenMetaverse) it is possible to develop clients for opensim servers that do unorthodox things such as bypassing the permissions system to copy people's assets. Bots written by griefers can do lots of other nasty things.

Malicious bots are a problem for all opensim administrators, including walled-garden grids. They can be prevented, to a certain extent, by exo-technical solutions such as Terms of Service and real-world lawsuits. Technically speaking, the only way to keep intruders out is to run opensim inside a firewall, pretty much like all other pieces of client/server software out there. If that's an acceptable solution for your case, you should do it.

Unfortunately firewalls also keep the public out, and most opensim operators, even the ones running walled-garden grids, want to reach out to the public. In this case, opensim operators may develop additional technical obstacles for bots, similar to those we see on the Web. For example, make sure agents are being run by real people by giving them a human-challenge during the login/TP process, etc.

Every obstacle to malicious clients lowers the risk of an intruder attack. However keep this in mind: no matter how many obstacles one builds, a sufficiently skilled and motivated attacker will be able to overcome them to penetrate opensims connected to the public internet. This affects hypergrid nodes as much as walled-garden grids. In fact, it's more pervasive than that: it affects '''all''' servers (opensim, web, etc.) connected to the public internet. Fighting malicious intruders is a fact of a connected world. Fortunately, those attacks don't happen very often, or the Web would have been dead by now.

==== Web Clients ====

CopyBots are the most well-known bots for opensim-based virtual worlds, but these virtual worlds are also susceptible to attacks by regular web clients. With the current state of things, it is actually easier to copy assets with a web-based client than with a libsl-based one. The weakness is that asset servers are connected to the public internet, and the protocol for interacting with them is public.

OpenSim has some minimal guards in place to fence against these kinds of attacks. Specifically, when the inventory server receives a request for an item, it checks the session identifier of the requester. Web clients aren't logged in, so they are refused service. I don't want to expand much more on this, so not to make life easy for attackers, but let's just say that opensim has the necessary mechanisms in place to fence off web-based attackers.

=== Malicious Hosts ===

==== Actively Malicious Hosts ====

The new security threat introduced by openness, one that does not exist in closed grids, is the possibility of a user to visit a region that is running malicious code. In the current state of opensim, a malicious host can do serious damage to the user's assets. Let's see how.

Assume you have your assets in your hypergrided-standalone opensim, and you go visit another opensim that happens to be running malicious code. Here is a non-exhaustive list of vulnerabilities that you are exposed to:

* The host has your session id, so it can request your inventory items on your behalf and store copies in its local asset server. To add insult to injury, a malicious host could simply wipe out your inventory after having copied it.
* Even if the malicious host doesn't access your items by itself, every time you access items in your inventory while you are in that region, those items are cached in the region's local cache, and can be stored persistently by the malicious host.

Malicious hosts can do a lot more damage, but those two are enough to illustrate this new kind of vulnerability affecting open grids. Note that this affects all open grids, i.e. those where arbitrary people can plug-in their opensims, and not just the hypergrid.

Fortunately, there is a family of simple solutions to this problem that can be summarized as "protecting you from yourself." That proposal is described [[Hypergrid Inventory Access|here]].

==== Piracy ====

A second new security threat affecting open grids is one pertaining to commerce of virtual goods. Suppose you put something out for sale on your hypergrided opensim. A foreign user comes and buys it. What that really means is that that user will physically get a copy of the assets moved to his/her asset server, which is different from your asset server. The permissions will be whatever you define them to be, and using the regular VW client, that user can only do what you defined he/she should could do with the object, as usual. However, if the user has direct backend access to the asset and inventory servers, that person can simply modify the permissions on his/her copy. This is commonly known as '''piracy'''. (This is also a problem with programmers who have direct access to the cache that their client keeps; in this case, the only thing that needs to be done to enable piracy is for the user to actually see a texture/animation/in-world object. This does NOT allow scripts to be copied, though, since the script is only interpreted on the server and is never sent for interpretation by the client.)

This situation is the kernel of the belief that open grids are hopeless for a virtual-goods economy. DRM discussion aside, maybe they are hopeless. But then, everyone thought the web was hopeless for selling music, and look at the success of iTunes in spite of all the piracy that still exists out there. Who will be the equivalent of iTunes for virtual hair, skin and clothes?

== Hypergrid Implementation ==

=== Hyperlinks and Agent Transfers ===

When you establish a link between your opensim and another, a message is sent out to that other opensim requesting information about it; the required information includes the network information of that opensim host, and the coordinates of its first region on its local grid in the form of a region handle. For example, suppose you are linking node X.com:9000, placing it in your local map at 900, 900. That opensim runs one or more regions that likely are not in 900, 900 on their own map; suppose the first region of that opensim is at 1100, 1100. From your point of view, it doesn't matter what those other coordinates are, and you don't need to know -- that's the key to being able to decentralize the "world" as given by a 2D map; you want to place it in your map at 900, 900. The "true" position of that simulator only matters for the LL viewer, when there are teleports between your world and that other opensim. This mapping between coordinate systems is the essence of hyperlinks for opensim; it's one simple but critical thing that the hypergrid implementation does. The mapping happens on the TeleportFinish event; instead of sending the local coordinates to the viewer, the hypergrid teleport wrapper sends the remote coordinates.

When an agent teleports through that hyperlink the following happens. First, before InformRegionOfChildAgent, the local opensim notifies the remote opensim of this foreign user via the "expect_hg_user" method. That message sends along the addresses of all the servers that this user uses, i.e. user, inventory and asset servers. The remote opensim places an entry for that user in its local user profile cache but not in its user database; the foreign user information is non-persistent. After that, the teleport process is exactly the same as the normal teleport process; the only difference is that the region handles are switched between the remote region's hyperlink position on the local grid and its actual position on its grid.

In summary, the two new concepts introduced by the hypergrid are the concept of an hyperlink and the concept of a "local user" vs. "foreign user".

=== Inventory Access ===

Inventory access from abroad is done by wrapping the existing scene-inventory interactions with additional code that gets or posts inventory assets from/to the user's asset server. When inventory is accessed, the hypergrid wrapper checks if the user is foreign and, if she is, the wrapper simply brings the necessary assets from the user's asset server to the local asset cache and server; from then on, the wrapper passes the control to the existing inventory access functions. When something is added to inventory, the hypergrid wrapper is notified via an event, and posts the assets to the user's asset server. A cache of the exchanged item identifiers is maintained so that they aren't brought back over and over again.

The result is that hypergrided opensim instances end up interacting with several asset servers, instead of just one. That interaction is implemented in a straightforward manner by instantiating several GridAssetClient objects, instead of just one.

=== The Hypergrid Namespace ===

Currently, the hypergrid is implemented outside of the OpenSim namespace, so that there is complete separation between what already exists and this new behavior. It has its own namespace, HyperGrid. In it, there are 4 sub-namespaces that follow directly the software architecture of OpenSim, namely:

* '''HyperGrid.Framework''' extends OpenSim.Framework in the following manner:
** HGUserProfileData extends UserProfileData by introducing information about the user's "home", namely the home address, port and remoting port. The user's home is not that user's user service; it's the opensim that the user has defined to be her home. This is necessary for supporting the home jump (Ctrl-Shift-H).
** HGNetworkServersInfo follows the spirit of NetworkServersInfo, although it neither extends it nor uses it. For now, it's a utility class whose two main functions are to convert domain names of servers to IP addresses, and to uniformly provide the answer to the question bool IsLocalUser(...).

* '''HyperGrid.Environment''' extends OpenSim.Region.Environment.Scenes in the following manner:
** HGSceneCommunicationService extends SceneCommunicationService, overriding RequestTeleportToLocation. There are two very small but critical changes to the base method: (a) on the TeleportFinish event, we switch the region handles when the destination region is an hyperlink; (b) the connections at the end are always closed for hyperlink TPs.
** HGScene extends Scene, overriding TeleportClientHome(...). The only change to the base method is to stay away from the user server, for now, because the user service is still not completely wrapped up for foreign users. Once the user service is properly wrapped up, this class will become unnecessary.
** HGScene.Inventory is a partial class of HGScene, just like what happens in the OpenSim framework. This part of HGScene overrides some inventory-scene interaction methods, so that assets are fetched/posted from/to the user's asset server. Once that extra fetching/posting is done, these methods simply pass the ball to the base methods.
** HGAssetMapper: this is a new class specific to the hypergrid that manages the fetching and posting of assets between foreign regions where the user is and the user's asset server.

* '''HyperGrid.Protocol''' is a mashup of OpenSim.Region.Communications.*. This is the place where most of the hypergrid extension lies. One of the reasons for this is that the hypergrid communications part is doing one additional thing: it is making standalones network-able.
** HGCommunicationsStandalone extends CommuniationsLocal. Just as its base, it is a hub for the several network services available in standalone mode. The main difference is that those services are extensions of what's in OpenSim.
** HGCommunicationsGridMode extends CommunicationsManager directly. Again, it's a hub for the network services available in grid mode, those services being extensions of OpenSim.
** The cluster HGGridServices (superclass), HGGridServicesStandalone and HGGridServicesGridMode (subclasses) implements the OpenSim interfaces IGridServices and IInterRegionCommunications. The 2 subclasses are wrappers for LocalBackEndServices and OGS1GridServices, respectively. There is one common pattern throughout these classes: check if the region to talk to is an hyperlink; if it's not, simply delegate the work to LocalBackEndServices/OGS1GridServices; if it is, push the work to the base class HGGridServices. HGGridServices, in turn, does the management of hyperlink regions, and defines two additional pieces of inter-region protocol:
*** region_uuid: for linking regions
*** expect_hg_user: similar to the existing expect_user interface, but with a lot more information about the user being passed around, namely all the user's servers (inventory, asset, user, home, etc.)
** HGInventoryService extends LocalInventoryService and implements ISecureInventoryService. This class is the most obvious mashup of the pack, mixing local service access for standalone users and remote inventory access for when users are out and about. Right now, there is a fair amount of selective copy-and-paste, to stay away from the ugliness coming from OGS1InventoryService and OGS1SecureInventoryService. HGInventoryService is always a ISecureInventoryService. Its methods all follow the same pattern: check if the user is a local standalone user; if it is, pass the work to the base method (in LocalInventoryService); if it's not perform secure remote access.
** HGUserServices wraps OSG1UserServices, but it's not functional yet.

* '''HyperGrid.Modules''' is a collection of 3 region modules:
** HGWorldMapModule extends WorldMapModule. It reuses almost everything from the base class. The only small change is in RequestMapBlocks, where it tries to send Offline mapblocks to the client.
** HGStandaloneInventoryService and HGStandaloneAssetService do what their names say. They are region modules that allow access to inventory and assets for standalones, when the standalone user is out and about. In spirit, there is a lot in common between these modules and the REST inventory/asset plugin. Unfortunately, that plugin could not be used because it defines a completely different interface than that used by existing inventory and asset servers, and the access for the hypergrid must use a consistent interface.

=== Class Diagram ===

[[image:HypergridImplementation.jpg|600px|center|(Click on the image to enlarge)]]

== Installing and Running Hypergrid ==

=== Installing ===

# Checkout OpenSim, prebuild and build as normal.
# Make the following changes to your OpenSim.ini:
#* The map: '''WorldMapModule = "HGWorldMap" ''' If you didn't have this setting in your original OpenSim.ini, make sure you place it under the [Startup] section.
#* If you're running your opensim in grid mode with the UGAIM servers on other machines, you're done. If you're running in standalone and you want it to be network-able, or if you have your grid on loopback (127.0.0.1) change all the [Network] server addresses to <nowiki>"http://<external_host_name>:<http_port>"</nowiki>. See below.
# Run opensim like this: <nowiki>[mono] OpenSim.exe -hypergrid=true</nowiki>. To make sure the hypergrid is running type this on your console: '''link-region'''. If you don't hear anything back, the hypergrid is not properly installed.

Here is an example of the Network settings for a standalone:

[Network]
http_listener_port = 9300
remoting_listener_port = 9895

grid_server_url = http://example.com:9300
grid_send_key = null
grid_recv_key = null

user_server_url = http://example.com:9300
user_send_key = null
user_recv_key = null

asset_server_url = http://example.com:9300
inventory_server_url = http://example.com:9300
messaging_server_url = http://example.com:9300

Here is an example of the Network settings for a grided opensim:

[Network]
http_listener_port = 9300
remoting_listener_port = 9895

grid_server_url = http://example.com:8001
grid_send_key = null
grid_recv_key = null

user_server_url = http://example.com:8002
user_send_key = null
user_recv_key = null

asset_server_url = http://example.com:8003
inventory_server_url = http://example.com:8004
; Port 8005 reserved
messaging_server_url = http://example.com:8006

'''Important Note'''

Make sure you have a 'home' set. If your home region doesn't exist, the hyperlink TPs may not work. To set your home, go to one of your local regions and "Set Home" from the viewer.

=== Linking regions ===
'''Method 1:'''

On the console, type for example:

link-region <Xloc> <Yloc> osl2.nac.uci.edu 9006 OSGrid Gateway

* Use Xloc and Yloc that make sense to your world, i.e. close to your regions, but not adjacent.
* replace osl2.nac.uci.edu and 9006 with the domain name / ip address and the port of the region you want to link to

'''Method 2:'''

There is also some initial support for reading the links from a xml file.

Use the console command: link-region <URI> [<excludeList>]

The uri can be either the path of a local xml file or a xml document on a http server.

The format of the xml file is:

<Nini>
<Section Name="Region1"> 
<Key Name="xloc" Value="1002"/>
<Key Name="yloc" Value="1006" />
<Key Name="externalPort" Value="9006" />
<Key Name="externalHostName" Value="osl2.nac.uci.edu" />
<Key Name="localName" Value="OSGrid-Gateway" />
<Key Name="real-xloc" Value="10222"/> //optional field that gives the region's real location on its home grid
<Key Name="real-yloc" Value="10265" /> //optional field that gives the region's real location on its home grid
</Section>
<Section Name="Region2">
...
</Section>
...
</Nini>

[Note] The section names can be anything you want, but they all should be different and have no spaces in the name.

ExcludeList:

The exclude list is a single string paramater with the format: excludeList:<SectionName>[;<SectionName>]

This means that while reading from the xml file any sections that are listed in the excludeList will be ignored and no HyperGrid link created for them.

This could allow, link lists to be created on a webserver that everyone could add their own regions to, and then they just make sure they add their own section name(s) to the exclude list on their own region(s).

So for example, someone might create a editable online list for the up coming OpenSimulator's 2nd birthday. Which might look something like:

<Nini>
<Section Name="OSGrid-Party"> 
<Key Name="xloc" Value="1002"/>
<Key Name="yloc" Value="1006" />
<Key Name="externalPort" Value="9006" />
<Key Name="externalHostName" Value="osl2.nac.uci.edu" />
<Key Name="localName" Value="OSGrid-Gateway" />
</Section>
<Section Name="UCIGrid-Party">
...
</Section>
</Nini>

I could then add my own region to the list with the section name "MW-Party". Then when I startup that region that I want to be part of this hypergrid, I use the command: "link-region <URI of xml file> excludeList:MW-Party"

This is so that my region doesn't try to create a hyper link to itself.

'''Important Note'''

Due to a viewer [https://jira.secondlife.com/browse/SVC-2941 bug], you can only TP between regions that are no more than 4096 cells apart in any dimension. What this means in practice is that if you want to link to OSGrid, you must have your own regions reachable from the (10,000; 10,000) point on the map, which is where OSGrid is centered. Place your regions somewhere in the 8,000s or the 12,000s.

== Public Hypergrid Nodes ==

Please see [[Public Hypergrid Nodes]].

== Hypergrid Lists ==
Please see [[Hypergrid Lists]].

Hypergrid Lists

2009-01-19T10:18:57Z

MWr: New page: == Hypergrid Lists == Draft 1: A new feature for hypergrids that is currently being worked on, is support for shared online lists of hypergrid links. So there could be various list s of ...

== Hypergrid Lists ==

Draft 1:

A new feature for hypergrids that is currently being worked on, is support for shared online lists of hypergrid links. So there could be various list s of a set of hypergrid enabled regions that all share a similar theme. And hopefully a lot of these lists will enable a user to add their own region data to that list.

Basically these lists will be a xml file, listing all the regions and the relevant data required for a hypergrid link; like their hostName and port number. Each region will also have a assigned "virtual location" within a 0,0 - 99,99 map area (the size of this area could change at a later data).

A user can then tell their own hypergrid enabled region to load that hypergrid list, by telling it the url of that list.

They user will also need to tell their own region how to deal with the location of those regions. So you can define a Hypergrid area, that is 99,99 region spaces in size, anywhere on your region's map. And then as your region loads that list, it will translate the link locations from the list (those assigned positions within that 0,0-99,99 area) into that hypergrid area. So if you had set the hypergrid area to start at location 2200, 2200. Then the link for the region that had a assigned list position of 2,2, will appear at 2202,2202 on your map.

The following image (not to scale) gives a basic overview, the regions on your home grid are the green squares and the orange area is the hypergrid area that you want the hypergrid regions to be in.

[[Image:HyperGrid-Area.png]]

The StartXLoc,StartYloc are the coordinates for the start of the hypergrid area that you need to set.

So there are two things that need to be done to load such a list.

First set the Start location for that hypergrid area using the console command: link-mapping <startXloc> <startYloc>

So for our example it would be: link-mapping 2200 2200

Next the region needs to be told to load the list by providing it with the url, using the console command : link-region <url> [excludeList]

That would result in the region fetching that xml file and creating all the links for the regions in that list.

----

However there are currently two problems with this.

The first being that if the details for your own region was in that list, it would try to create a link to itself. So this is where the excludeList parameter (mentioned above ) comes in.

The details for each region in a list includes a "Section Name" which can be anything as long as it has no spaces and each region has a unique one. This is the name that you need to include in the excludelist, so that you region knows to ignore that data.

So if my region had a section name of "Hyper-Gateway1" in the list, I would need to use the command: link-region <url of list> excludeList:Hyper-Gateway1

How the section names are actually set will depend on how and where the list is hosted. And as there are no such lists at the time of writing, its not possible to give instructions on how to find that name. But hopefully each list will have some instructions on either setting your own section name or how to find it if they assign one for you.

The second problem is that due to a bug in the viewer, teleports can only happen between regions that are within 4096,4096 map spaces of each other. As you should know from reading the rest of this page, Hypergrid regions have two map locations, their real location where they are on their home region. And the "virtual map location" somewhere within your hypergrid area, which is really just a local link to the real location.

For this bug, its the real location that matters. So when trying to teleport to a hypergrid region, there can't be more than a 4096,4096 difference between the location that you are currently on and the real location of the hypergrid region.

To get around this, the list can include details of a region's real location. And then currently when a list is loaded, your region will check that this real location is within the 4096,4096 range of its potential "virtual map location". If it is outside that limit, then no link will be created for that region.

This is all done automatically so there is nothing the user has to do.

2009-01-16T17:48:49Z

MWr: /* Hypergrid Lists */

==The OpenSim Hypergrid==

=== What is the hypergrid? ===


The hypergrid is an extension to opensim that allows you to link your opensim to other opensims on the internet, and that supports seamless agent transfers among those opensims. It can be used both in standalone mode and in grid mode. The hypergrid is effectively supporting the emergence of a Web of virtual worlds.

The basic idea for the hypergrid is that region/grid administrations can place hyperlinks on their map to hypergrided regions run by others. Once those hyperlinks are established, users interact with those regions in exactly the same way as they interact with local regions. Specifically, users can choose to teleport there. Once the user reaches the region behind the hyperlink, she is automatically interacting with a different virtual world without having to logout from the world where she came from, and while still having access to her inventory.

The hypergrid started as a GForge project, but it is now included in the standard distribution of OpenSim. To run your OpenSim instance in hypergrid mode, please see [[Hypergrid#Installing_and_Running_Hypergrid|Installing and Running]].

=== Virtual World Hyperlinks ===
[[image:hghyperlink.jpg|250px|thumb|A Virtual World Hyperlink]]

We're all familiar with hypertext links on the Web. But what is a virtual world hyperlink?

In the hypergrid model, we consider the 2D map of the virtual world as the equivalent of a web page. As such, a VW hyperlink is simply a region on that map.

The default model of opensim-based virtual worlds already supports this concept of hyperlink, to some extent. When you teleport from one region to another via the map, chances are you are migrating your agent into a different opensim server. This migration is a glorified "agent transfer" that also exists, in rudimentary form, on the web when hypertext links are followed. The default model, however, imposes two very strong constraints on these hyperlinks:
# The entire map of regions is controlled by a central service known as the grid service, whose job is to provide a uniform view of the world to all of its regions.
# The only agents that can be transferred are those pertaining to users known to another central service, the user service; if the incoming user is not on that service's database, the agent transfer doesn't go through.

The hypergrid simply removes these two constraints.

First, it allows individual opensim instances to add "neighbors" to their local map, shifting the control of the map down from the grid server to individual opensim instances (although hyperlinks can also be served by grid servers if grid admins so wish). In doing so, the world becomes a lot more interesting and varied. The map that you see in one opensim instance may be completely different from the map that you see after you teleport via an hyperlink. As an opensim administrator, you are free to define what other opensims you want to see on your map.

Second, it allows the transfer of agents pertaining to foreigner users, i.e. users who are registered elsewhere. Instead of assuming one central user service, the hypergrid assumes an arbitrarily large number of such services distributed all over the world. As such, when agents are transferred among hypergrided opensims, a lot more information is passed about the corresponding user. That information includes the collection of servers that the transferring user needs.

=== Usage Scenarios ===

The following are some usage scenarios. There isn't a clear separation between these scenarios, there's a large overlap between them. This is also not an exhaustive list. The purpose of these descriptions is to give you some starting ideas for how to use the hypergrid in practice. Please feel free to add other interesting scenarios to this list.

{| {{Prettytable}}
|-
|
[[image:topoA.jpg|400px|left]]
|
'''Personal Worlds'''

This first scenario pertains to standalone opensims. Normally, standalones are completely disconnected from the internet. However, when run in hypergrid mode, standalones become network-able. As such, you can run your own world in your own computer, and link your world to whoever you want. For example, you can link to your friends' hypergrided opensims and to hypergrid gateways in open grids such as OSGrid.

The great thing about this scenario is that all of your assets are stored on your computer, and not on somebody else's server. You can back them up using ordinary backend tools. The not so great thing about this scenario is that all of your assets are stored on your computer! If your disk goes berserk, you loose them. (so make sure you make external backups regularly)

|-
|
[[image:topoB.jpg|400px|left]]
|
'''Communities'''

This second scenario is about communities, broadly construed. The idea here is that a group of people come together to support a small community grid, i.e. a common world where shared activities take place. But at the same time, the members of the community maintain their own standalone worlds. The standalones link to the community grid, and the community grid may link back to the individual members' worlds and other places of interest.

The members' identities are probably the identities they have on their standalones, and their assets are also probably stored there. The assets present in the community regions, however, are stored on the grid asset server.

|-
|
[[image:topoC.jpg|400px|left]]
|
'''Grid Public Regions'''

Walled-gardens are here to stay, and they serve many useful purposes. There is a hybrid mode for the hypergrid that some walled-garden grid operators may be interested in supporting. In this hybrid mode, most opensim instances on the grid run in normal, wall-garden mode, so no foreign visitors are allowed there - technically it is impossible to reach them. However, a few opensim instances on that grid can run in hypergrid mode, so that foreign visitors are allowed. This way, there is a gateway for grid-local users and arbitrary visitors to meet. This is also a good strategy for attracting new users to the grid, since random users are able to visit those gateway regions without having to sign up for an account upfront.

This hybrid mode is very similar to what happens on the web. For example, anyone can visit Facebook's public pages without having to sign up for a Facebook account. However, only Facebook users can go further inside.

|-
|
[[image:topoD.jpg|400px|left]]
|
'''Level Games'''

The normal version of OpenSim enforces a common map for all the regions on a grid. The hypergrid removes that constraint. As such, it becomes easy to design VW games where the world looks different depending of where the player is.

|-
|}

== Security Concerns ==

There is a wide-spread assumption that open grids such as OSGrid and new forms of grids such as the hypergrid are inherently insecure, and that it will be impossible to develop a "goods-based" economy on top of them; only walled-gardens can be secured. This is both true and false. While it is true with the current state of things, open grids, whatever their form, can be made as secure as the web. The first step towards that is to define exactly what the security threats are, and how they affect (or not) open and closed grids. So, let's spell them out, and face them head-on. This will help put our feet on the ground so that we start developing appropriate solutions.

=== Malicious Clients ===

==== CopyBots ====

Everyone knows about the infamous [http://en.wikipedia.org/wiki/CopyBot CopyBot]. Using libraries such as [http://www.libsecondlife.org/wiki/Main_Page LibSL] (now known as OpenMetaverse) it is possible to develop clients for opensim servers that do unorthodox things such as bypassing the permissions system to copy people's assets. Bots written by griefers can do lots of other nasty things.

Malicious bots are a problem for all opensim administrators, including walled-garden grids. They can be prevented, to a certain extent, by exo-technical solutions such as Terms of Service and real-world lawsuits. Technically speaking, the only way to keep intruders out is to run opensim inside a firewall, pretty much like all other pieces of client/server software out there. If that's an acceptable solution for your case, you should do it.

Unfortunately firewalls also keep the public out, and most opensim operators, even the ones running walled-garden grids, want to reach out to the public. In this case, opensim operators may develop additional technical obstacles for bots, similar to those we see on the Web. For example, make sure agents are being run by real people by giving them a human-challenge during the login/TP process, etc.

Every obstacle to malicious clients lowers the risk of an intruder attack. However keep this in mind: no matter how many obstacles one builds, a sufficiently skilled and motivated attacker will be able to overcome them to penetrate opensims connected to the public internet. This affects hypergrid nodes as much as walled-garden grids. In fact, it's more pervasive than that: it affects '''all''' servers (opensim, web, etc.) connected to the public internet. Fighting malicious intruders is a fact of a connected world. Fortunately, those attacks don't happen very often, or the Web would have been dead by now.

==== Web Clients ====

CopyBots are the most well-known bots for opensim-based virtual worlds, but these virtual worlds are also susceptible to attacks by regular web clients. With the current state of things, it is actually easier to copy assets with a web-based client than with a libsl-based one. The weakness is that asset servers are connected to the public internet, and the protocol for interacting with them is public.

OpenSim has some minimal guards in place to fence against these kinds of attacks. Specifically, when the inventory server receives a request for an item, it checks the session identifier of the requester. Web clients aren't logged in, so they are refused service. I don't want to expand much more on this, so not to make life easy for attackers, but let's just say that opensim has the necessary mechanisms in place to fence off web-based attackers.

=== Malicious Hosts ===

==== Actively Malicious Hosts ====

The new security threat introduced by openness, one that does not exist in closed grids, is the possibility of a user to visit a region that is running malicious code. In the current state of opensim, a malicious host can do serious damage to the user's assets. Let's see how.

Assume you have your assets in your hypergrided-standalone opensim, and you go visit another opensim that happens to be running malicious code. Here is a non-exhaustive list of vulnerabilities that you are exposed to:

* The host has your session id, so it can request your inventory items on your behalf and store copies in its local asset server. To add insult to injury, a malicious host could simply wipe out your inventory after having copied it.
* Even if the malicious host doesn't access your items by itself, every time you access items in your inventory while you are in that region, those items are cached in the region's local cache, and can be stored persistently by the malicious host.

Malicious hosts can do a lot more damage, but those two are enough to illustrate this new kind of vulnerability affecting open grids. Note that this affects all open grids, i.e. those where arbitrary people can plug-in their opensims, and not just the hypergrid.

Fortunately, there is a family of simple solutions to this problem that can be summarized as "protecting you from yourself." That proposal is described [[Hypergrid Inventory Access|here]].

==== Piracy ====

A second new security threat affecting open grids is one pertaining to commerce of virtual goods. Suppose you put something out for sale on your hypergrided opensim. A foreign user comes and buys it. What that really means is that that user will physically get a copy of the assets moved to his/her asset server, which is different from your asset server. The permissions will be whatever you define them to be, and using the regular VW client, that user can only do what you defined he/she should could do with the object, as usual. However, if the user has direct backend access to the asset and inventory servers, that person can simply modify the permissions on his/her copy. This is commonly known as '''piracy'''. (This is also a problem with programmers who have direct access to the cache that their client keeps; in this case, the only thing that needs to be done to enable piracy is for the user to actually see a texture/animation/in-world object. This does NOT allow scripts to be copied, though, since the script is only interpreted on the server and is never sent for interpretation by the client.)

This situation is the kernel of the belief that open grids are hopeless for a virtual-goods economy. DRM discussion aside, maybe they are hopeless. But then, everyone thought the web was hopeless for selling music, and look at the success of iTunes in spite of all the piracy that still exists out there. Who will be the equivalent of iTunes for virtual hair, skin and clothes?

== Hypergrid Implementation ==

=== Hyperlinks and Agent Transfers ===

When you establish a link between your opensim and another, a message is sent out to that other opensim requesting information about it; the required information includes the network information of that opensim host, and the coordinates of its first region on its local grid in the form of a region handle. For example, suppose you are linking node X.com:9000, placing it in your local map at 900, 900. That opensim runs one or more regions that likely are not in 900, 900 on their own map; suppose the first region of that opensim is at 1100, 1100. From your point of view, it doesn't matter what those other coordinates are, and you don't need to know -- that's the key to being able to decentralize the "world" as given by a 2D map; you want to place it in your map at 900, 900. The "true" position of that simulator only matters for the LL viewer, when there are teleports between your world and that other opensim. This mapping between coordinate systems is the essence of hyperlinks for opensim; it's one simple but critical thing that the hypergrid implementation does. The mapping happens on the TeleportFinish event; instead of sending the local coordinates to the viewer, the hypergrid teleport wrapper sends the remote coordinates.

When an agent teleports through that hyperlink the following happens. First, before InformRegionOfChildAgent, the local opensim notifies the remote opensim of this foreign user via the "expect_hg_user" method. That message sends along the addresses of all the servers that this user uses, i.e. user, inventory and asset servers. The remote opensim places an entry for that user in its local user profile cache but not in its user database; the foreign user information is non-persistent. After that, the teleport process is exactly the same as the normal teleport process; the only difference is that the region handles are switched between the remote region's hyperlink position on the local grid and its actual position on its grid.

In summary, the two new concepts introduced by the hypergrid are the concept of an hyperlink and the concept of a "local user" vs. "foreign user".

=== Inventory Access ===

Inventory access from abroad is done by wrapping the existing scene-inventory interactions with additional code that gets or posts inventory assets from/to the user's asset server. When inventory is accessed, the hypergrid wrapper checks if the user is foreign and, if she is, the wrapper simply brings the necessary assets from the user's asset server to the local asset cache and server; from then on, the wrapper passes the control to the existing inventory access functions. When something is added to inventory, the hypergrid wrapper is notified via an event, and posts the assets to the user's asset server. A cache of the exchanged item identifiers is maintained so that they aren't brought back over and over again.

The result is that hypergrided opensim instances end up interacting with several asset servers, instead of just one. That interaction is implemented in a straightforward manner by instantiating several GridAssetClient objects, instead of just one.

=== The Hypergrid Namespace ===

Currently, the hypergrid is implemented outside of the OpenSim namespace, so that there is complete separation between what already exists and this new behavior. It has its own namespace, HyperGrid. In it, there are 4 sub-namespaces that follow directly the software architecture of OpenSim, namely:

* '''HyperGrid.Framework''' extends OpenSim.Framework in the following manner:
** HGUserProfileData extends UserProfileData by introducing information about the user's "home", namely the home address, port and remoting port. The user's home is not that user's user service; it's the opensim that the user has defined to be her home. This is necessary for supporting the home jump (Ctrl-Shift-H).
** HGNetworkServersInfo follows the spirit of NetworkServersInfo, although it neither extends it nor uses it. For now, it's a utility class whose two main functions are to convert domain names of servers to IP addresses, and to uniformly provide the answer to the question bool IsLocalUser(...).

* '''HyperGrid.Environment''' extends OpenSim.Region.Environment.Scenes in the following manner:
** HGSceneCommunicationService extends SceneCommunicationService, overriding RequestTeleportToLocation. There are two very small but critical changes to the base method: (a) on the TeleportFinish event, we switch the region handles when the destination region is an hyperlink; (b) the connections at the end are always closed for hyperlink TPs.
** HGScene extends Scene, overriding TeleportClientHome(...). The only change to the base method is to stay away from the user server, for now, because the user service is still not completely wrapped up for foreign users. Once the user service is properly wrapped up, this class will become unnecessary.
** HGScene.Inventory is a partial class of HGScene, just like what happens in the OpenSim framework. This part of HGScene overrides some inventory-scene interaction methods, so that assets are fetched/posted from/to the user's asset server. Once that extra fetching/posting is done, these methods simply pass the ball to the base methods.
** HGAssetMapper: this is a new class specific to the hypergrid that manages the fetching and posting of assets between foreign regions where the user is and the user's asset server.

* '''HyperGrid.Protocol''' is a mashup of OpenSim.Region.Communications.*. This is the place where most of the hypergrid extension lies. One of the reasons for this is that the hypergrid communications part is doing one additional thing: it is making standalones network-able.
** HGCommunicationsStandalone extends CommuniationsLocal. Just as its base, it is a hub for the several network services available in standalone mode. The main difference is that those services are extensions of what's in OpenSim.
** HGCommunicationsGridMode extends CommunicationsManager directly. Again, it's a hub for the network services available in grid mode, those services being extensions of OpenSim.
** The cluster HGGridServices (superclass), HGGridServicesStandalone and HGGridServicesGridMode (subclasses) implements the OpenSim interfaces IGridServices and IInterRegionCommunications. The 2 subclasses are wrappers for LocalBackEndServices and OGS1GridServices, respectively. There is one common pattern throughout these classes: check if the region to talk to is an hyperlink; if it's not, simply delegate the work to LocalBackEndServices/OGS1GridServices; if it is, push the work to the base class HGGridServices. HGGridServices, in turn, does the management of hyperlink regions, and defines two additional pieces of inter-region protocol:
*** region_uuid: for linking regions
*** expect_hg_user: similar to the existing expect_user interface, but with a lot more information about the user being passed around, namely all the user's servers (inventory, asset, user, home, etc.)
** HGInventoryService extends LocalInventoryService and implements ISecureInventoryService. This class is the most obvious mashup of the pack, mixing local service access for standalone users and remote inventory access for when users are out and about. Right now, there is a fair amount of selective copy-and-paste, to stay away from the ugliness coming from OGS1InventoryService and OGS1SecureInventoryService. HGInventoryService is always a ISecureInventoryService. Its methods all follow the same pattern: check if the user is a local standalone user; if it is, pass the work to the base method (in LocalInventoryService); if it's not perform secure remote access.
** HGUserServices wraps OSG1UserServices, but it's not functional yet.

* '''HyperGrid.Modules''' is a collection of 3 region modules:
** HGWorldMapModule extends WorldMapModule. It reuses almost everything from the base class. The only small change is in RequestMapBlocks, where it tries to send Offline mapblocks to the client.
** HGStandaloneInventoryService and HGStandaloneAssetService do what their names say. They are region modules that allow access to inventory and assets for standalones, when the standalone user is out and about. In spirit, there is a lot in common between these modules and the REST inventory/asset plugin. Unfortunately, that plugin could not be used because it defines a completely different interface than that used by existing inventory and asset servers, and the access for the hypergrid must use a consistent interface.

=== Class Diagram ===

[[image:HypergridImplementation.jpg|600px|center|(Click on the image to enlarge)]]

== Installing and Running Hypergrid ==

=== Installing ===

# Checkout OpenSim, prebuild and build as normal.
# Make the following changes to your OpenSim.ini:
#* The map: '''WorldMapModule = "HGWorldMap" ''' If you didn't have this setting in your original OpenSim.ini, make sure you place it under the [Startup] section.
#* If you're running your opensim in grid mode with the UGAIM servers on other machines, you're done. If you're running in standalone and you want it to be network-able, or if you have your grid on loopback (127.0.0.1) change all the [Network] server addresses to <nowiki>"http://<external_host_name>:<http_port>"</nowiki>. See below.
# Run opensim like this: <nowiki>[mono] OpenSim.exe -hypergrid=true</nowiki>. To make sure the hypergrid is running type this on your console: '''link-region'''. If you don't hear anything back, the hypergrid is not properly installed.

Here is an example of the Network settings for a standalone:

[Network]
http_listener_port = 9300
remoting_listener_port = 9895

grid_server_url = http://example.com:9300
grid_send_key = null
grid_recv_key = null

user_server_url = http://example.com:9300
user_send_key = null
user_recv_key = null

asset_server_url = http://example.com:9300
inventory_server_url = http://example.com:9300
messaging_server_url = http://example.com:9300

Here is an example of the Network settings for a grided opensim:

[Network]
http_listener_port = 9300
remoting_listener_port = 9895

grid_server_url = http://example.com:8001
grid_send_key = null
grid_recv_key = null

user_server_url = http://example.com:8002
user_send_key = null
user_recv_key = null

asset_server_url = http://example.com:8003
inventory_server_url = http://example.com:8004
; Port 8005 reserved
messaging_server_url = http://example.com:8006

'''Important Note'''

Make sure you have a 'home' set. If your home region doesn't exist, the hyperlink TPs may not work. To set your home, go to one of your local regions and "Set Home" from the viewer.

=== Linking regions ===
'''Method 1:'''

On the console, type for example:

link-region <Xloc> <Yloc> osl2.nac.uci.edu 9006 OSGrid Gateway

* Use Xloc and Yloc that make sense to your world, i.e. close to your regions, but not adjacent.
* replace osl2.nac.uci.edu and 9006 with the domain name / ip address and the port of the region you want to link to

'''Method 2:'''

There is also some initial support for reading the links from a xml file.

Use the console command: link-region <URI> [<excludeList>]

The uri can be either the path of a local xml file or a xml document on a http server.

The format of the xml file is:

<Nini>
<Section Name="Region1"> 
<Key Name="xloc" Value="1002"/>
<Key Name="yloc" Value="1006" />
<Key Name="externalPort" Value="9006" />
<Key Name="externalHostName" Value="osl2.nac.uci.edu" />
<Key Name="localName" Value="OSGrid-Gateway" />
</Section>
<Section Name="Region2">
...
</Section>
...
</Nini>

[Note] The section names can be anything you want, but they all should be different and have no spaces in the name.

ExcludeList:

The exclude list is a single string paramater with the format: excludeList:<SectionName>[;<SectionName>]

This means that while reading from the xml file any sections that are listed in the excludeList will be ignored and no HyperGrid link created for them.

This could allow, link lists to be created on a webserver that everyone could add their own regions to, and then they just make sure they add their own section name(s) to the exclude list on their own region(s).

So for example, someone might create a editable online list for the up coming OpenSimulator's 2nd birthday. Which might look something like:

<Nini>
<Section Name="OSGrid-Party"> 
<Key Name="xloc" Value="1002"/>
<Key Name="yloc" Value="1006" />
<Key Name="externalPort" Value="9006" />
<Key Name="externalHostName" Value="osl2.nac.uci.edu" />
<Key Name="localName" Value="OSGrid-Gateway" />
</Section>
<Section Name="UCIGrid-Party">
...
</Section>
</Nini>

I could then add my own region to the list with the section name "MW-Party". Then when I startup that region that I want to be part of this hypergrid, I use the command: "link-region <URI of xml file> excludeList:MW-Party"

This is so that my region doesn't try to create a hyper link to itself.

'''Important Note'''

Due to a viewer [https://jira.secondlife.com/browse/SVC-2941 bug], you can only TP between regions that are no more than 4096 cells apart in any dimension. What this means in practice is that if you want to link to OSGrid, you must have your own regions reachable from the (10,000; 10,000) point on the map, which is where OSGrid is centered. Place your regions somewhere in the 8,000s or the 12,000s.

== Public Hypergrid Nodes ==

Please see [[Public Hypergrid Nodes]].

The following is a list of hypergrid-ready nodes that you can use for testing your installation and for linking your world. Please add your public node here if you wish to help build a web of opensims!

For the time being, and until the security concerns described above are addressed, we advise you to be careful about who you link to.

* '''osl2.nac.uci.edu 9006'''
The "UCI Welcome" region connected to OSGrid. It is run by Diva (Crista Lopes) on a machine owned by the University of California, Irvine. You can link to it as a way to link to OSGrid.

* '''ucigrid02.nacs.uci.edu 9000'''
A region in the UCI Grid. It is run by Diva (Crista Lopes) on a machine owned by the University of California, Irvine.

* '''grid.cyberlandia.net 9000'''
The "Cyberlandia Gw" region. http://www.cyberlandia.net Metaverso italiano 3D, more to 250 region and 1000 users. You can link to it as a way to link to Cyberlandia.

* '''hypergrid.cyberlandia.net 9000'''
The "Osgrid Gw" region connected to Cyberlandia grid http://www.cyberlandia.net. Search on map "Cyberlandia grid" You can link to it as a way to link to OSGrid.

* '''joomla-italia.net 9000
The "SNI City" region connected to SNI (Social Network Italia) grid http://www.opensim-italia.net. This grid is connected with Osgrid,Collateral World,Francogrid and Darwin

* '''collateral.opensim-italia.net 9000
[Collateral World is CLOSED and now is part of SNI]

* '''88.191.79.199 9050'''
Francogrid node, connected to "City", behind the welcome land of Francogrid "Orion"

* '''94.23.8.158 9999'''
Le Monde de Darwin node, The Lost of Darwin http://www.LeMondedeDarwin.com
----
[[Image:hypergrid.jpg]]
----

* '''grid.k-grid.com 9000'''
K-grid, [http://k-grid.com the Kool grid for the Kool KidZ] . Feel free to visit us. The main Gateway is located at 3700,3700 so take that in account before any HyperJump

* '''metropolis.hypergrid.org 9000'''
The Region "Center-World" (at 1000:1000) connected to the METROPOLIS-Grid http://metropolis.hypergrid.org . German Grid with a lot of free Content and free SIM-hosting. Connected via HG to the most of the Grids listed here.

* '''ascent.bluewallgroup.com 9910'''
This region is in a good proximity @ (6000,6000) for intermediate jumps to OSGrid from grids in the (2000,2000) range, or any region within 4096 units. [[Image:Hypernaut 001.png|150px|none|thumb|Get your Hypernaut here :)]]

* '''sim.thestudyofracialism.org 9000'''
TSOR1 is a stand-alone sim (at 4000,4000) owned by '''Backintyme Publishing'''. It connects to most of the other downrange sites listed here. Although currently sparse, the sim is eventually intended for an SL discussion-group's migration from SL to OS.

* '''pc.backintyme.com 9100'''
TSOR2 is a small teleport relay island (at 8000,8000), also owned by '''Backintyme Publishing''', intended for jumps to the vicinity of OSGrid. It is linked to most of the uprange sites listed here.

* '''http://myopengrid.com 9000'''
Myopengrid is connected to osl2.nac.uci.edu "Osgrid Gateway" our regions are at (7000,7000).

* '''cuonsim1.de 9300'''
Cuon-Grid is a little grid and has some Main Sims with linux themes, Regions are at (10000,10000),server are in Germany.To login in to the grid use this http://sim-linuxmain.org:8081/CuonGrid/index.html. There are free sims for testing.

* '''metaversesims.net 9014'''
Standalone mode - 6 regions at (9000,9000) - linked to the grids shown below
----
[[Image:Mtvs09010101.jpg]]
----

== Hypergrid Lists ==

Draft 1:

A new feature for hypergrids that is currently being worked on, is support for shared online lists of hypergrid links. So there might be a list somewhere of a set of hypergrid enabled regions that all share a similar theme. And hopefully a lot of these lists will enable a user to add their own region data to that list.

Basically these lists will be a xml file, listing all the regions and the relevant data required for a hypergrid link; like their hostName and port number. Each region will have a assigned "virtual location" within a 0,0 - 99,99 map area (the size of this area could change at a later data).

A user can then tell their own hypergrid enabled region to load that hypergrid list, by telling their region the url of that list.

They also will need to tell there own region how to deal with the location of those region. So you can define a Hypergrid area, that is 99,99 region spaces in size, anywhere on your region's map. And then as your region loads that list, it will tranlate the link locations from the list (those assigned positions within that 0,0-99,99 area) into that hypergrid area. So if you had set the hypergrid area to start at location 2200, 2200. Then the link for the region that had a assigned list position of 2,2, will appear at 2202,2202 on your map.

The following image gives a basic overview, the regions on your home grid are the green squares and the orange area is the hypergrid area that you want the hypergrid regions into.

[[Image:HyperGrid-Area.png]]

The StartXLoc,StartYloc are the coordinates for the start of the hypergrid area that you need to set.

So there are two things that need to be done to load such a list.

First set the Start location for that hypergrid area using the console command: link-mapping <startXloc> <startYloc>

So for our example it would be: link-mapping 2200 2200

Next the region needs to be told to load the list by providing it with the url, using the console command : link-region <url> [excludeList]

That would result in the region fetching that xml file and creating all the links for the regions in that list.

----

However there are currently two problems with this.

The first being that if the details for your own region was in that list, it would try to create a link to itself. So this is where the excludeList parameter (mentioned above ) comes in.

The details for each region in a list includes a "Section Name" which can be anything as long as it has no spaces and each region has a unique one. This is the name that you need to include in the excludelist, so that you region knows to ignore that data.

So if my region had a section name of "Hyper-Gateway1" in the list, I would need to use the command: link-region <url of list> excludeList:Hyper-Gateway1

How the section names are actually set will depend on how and where the list is hosted. And as there are no such lists at the time of writing no such lists, its not possible to give instructions on how to find that name. But hopefully each list will have some instructions on either setting your own section name or how to find it if they assign one for you.

The second problem is that due to a bug in the viewer, teleports can only happen between regions that are within 4096,4096 map spaces of each other. As you should know from reading the rest of this page, Hypergrid regions have two map locations, their real location where they are on their home region. And the "virtual map location" somewhere within your hypergrid area, which is really just a local link to the real location.

For this bug, its the real location that matters. So when trying to teleport to a hypergrid region, there can't be more than a 4096,4096 difference between the location that you are currently on and the real location of the hypergrid region.

To get around this, the list can include details of a region's real location. And then currently when a list is loaded, your region will check that this real location is within the 4096,4096 range of its potential "virtual map location". If it is outside that limit, then no link will be created for that region.

This is all done automatically so there is nothing the user has to do.

File:HyperGrid-Area.png

2009-01-16T17:24:49Z

MWr: uploaded a new version of "Image:HyperGrid-Area.png"

File:HyperGrid-Area.png

2009-01-16T17:22:46Z

MWr: uploaded a new version of "Image:HyperGrid-Area.png"

2009-01-15T14:50:55Z

MWr: /* Linking regions */

==The OpenSim Hypergrid==

=== What is the hypergrid? ===


The hypergrid is an extension to opensim that allows you to link your opensim to other opensims on the internet, and that supports seamless agent transfers among those opensims. It can be used both in standalone mode and in grid mode. The hypergrid is effectively supporting the emergence of a Web of virtual worlds.

The basic idea for the hypergrid is that region/grid administrations can place hyperlinks on their map to hypergrided regions run by others. Once those hyperlinks are established, users interact with those regions in exactly the same way as they interact with local regions. Specifically, users can choose to teleport there. Once the user reaches the region behind the hyperlink, she is automatically interacting with a different virtual world without having to logout from the world where she came from, and while still having access to her inventory.

The hypergrid started as a GForge project, but it is now included in the standard distribution of OpenSim. To run your OpenSim instance in hypergrid mode, please see [[Hypergrid#Installing_and_Running_Hypergrid|Installing and Running]].

=== Virtual World Hyperlinks ===
[[image:hghyperlink.jpg|250px|thumb|A Virtual World Hyperlink]]

We're all familiar with hypertext links on the Web. But what is a virtual world hyperlink?

In the hypergrid model, we consider the 2D map of the virtual world as the equivalent of a web page. As such, a VW hyperlink is simply a region on that map.

The default model of opensim-based virtual worlds already supports this concept of hyperlink, to some extent. When you teleport from one region to another via the map, chances are you are migrating your agent into a different opensim server. This migration is a glorified "agent transfer" that also exists, in rudimentary form, on the web when hypertext links are followed. The default model, however, imposes two very strong constraints on these hyperlinks:
# The entire map of regions is controlled by a central service known as the grid service, whose job is to provide a uniform view of the world to all of its regions.
# The only agents that can be transferred are those pertaining to users known to another central service, the user service; if the incoming user is not on that service's database, the agent transfer doesn't go through.

The hypergrid simply removes these two constraints.

First, it allows individual opensim instances to add "neighbors" to their local map, shifting the control of the map down from the grid server to individual opensim instances (although hyperlinks can also be served by grid servers if grid admins so wish). In doing so, the world becomes a lot more interesting and varied. The map that you see in one opensim instance may be completely different from the map that you see after you teleport via an hyperlink. As an opensim administrator, you are free to define what other opensims you want to see on your map.

Second, it allows the transfer of agents pertaining to foreigner users, i.e. users who are registered elsewhere. Instead of assuming one central user service, the hypergrid assumes an arbitrarily large number of such services distributed all over the world. As such, when agents are transferred among hypergrided opensims, a lot more information is passed about the corresponding user. That information includes the collection of servers that the transferring user needs.

=== Usage Scenarios ===

The following are some usage scenarios. There isn't a clear separation between these scenarios, there's a large overlap between them. This is also not an exhaustive list. The purpose of these descriptions is to give you some starting ideas for how to use the hypergrid in practice. Please feel free to add other interesting scenarios to this list.

{| {{Prettytable}}
|-
|
[[image:topoA.jpg|400px|left]]
|
'''Personal Worlds'''

This first scenario pertains to standalone opensims. Normally, standalones are completely disconnected from the internet. However, when run in hypergrid mode, standalones become network-able. As such, you can run your own world in your own computer, and link your world to whoever you want. For example, you can link to your friends' hypergrided opensims and to hypergrid gateways in open grids such as OSGrid.

The great thing about this scenario is that all of your assets are stored on your computer, and not on somebody else's server. You can back them up using ordinary backend tools. The not so great thing about this scenario is that all of your assets are stored on your computer! If your disk goes berserk, you loose them. (so make sure you make external backups regularly)

|-
|
[[image:topoB.jpg|400px|left]]
|
'''Communities'''

This second scenario is about communities, broadly construed. The idea here is that a group of people come together to support a small community grid, i.e. a common world where shared activities take place. But at the same time, the members of the community maintain their own standalone worlds. The standalones link to the community grid, and the community grid may link back to the individual members' worlds and other places of interest.

The members' identities are probably the identities they have on their standalones, and their assets are also probably stored there. The assets present in the community regions, however, are stored on the grid asset server.

|-
|
[[image:topoC.jpg|400px|left]]
|
'''Grid Public Regions'''

Walled-gardens are here to stay, and they serve many useful purposes. There is a hybrid mode for the hypergrid that some walled-garden grid operators may be interested in supporting. In this hybrid mode, most opensim instances on the grid run in normal, wall-garden mode, so no foreign visitors are allowed there - technically it is impossible to reach them. However, a few opensim instances on that grid can run in hypergrid mode, so that foreign visitors are allowed. This way, there is a gateway for grid-local users and arbitrary visitors to meet. This is also a good strategy for attracting new users to the grid, since random users are able to visit those gateway regions without having to sign up for an account upfront.

This hybrid mode is very similar to what happens on the web. For example, anyone can visit Facebook's public pages without having to sign up for a Facebook account. However, only Facebook users can go further inside.

|-
|
[[image:topoD.jpg|400px|left]]
|
'''Level Games'''

The normal version of OpenSim enforces a common map for all the regions on a grid. The hypergrid removes that constraint. As such, it becomes easy to design VW games where the world looks different depending of where the player is.

|-
|}

== Security Concerns ==

There is a wide-spread assumption that open grids such as OSGrid and new forms of grids such as the hypergrid are inherently insecure, and that it will be impossible to develop a "goods-based" economy on top of them; only walled-gardens can be secured. This is both true and false. While it is true with the current state of things, open grids, whatever their form, can be made as secure as the web. The first step towards that is to define exactly what the security threats are, and how they affect (or not) open and closed grids. So, let's spell them out, and face them head-on. This will help put our feet on the ground so that we start developing appropriate solutions.

=== Malicious Clients ===

==== CopyBots ====

Everyone knows about the infamous [http://en.wikipedia.org/wiki/CopyBot CopyBot]. Using libraries such as [http://www.libsecondlife.org/wiki/Main_Page LibSL] (now known as OpenMetaverse) it is possible to develop clients for opensim servers that do unorthodox things such as bypassing the permissions system to copy people's assets. Bots written by griefers can do lots of other nasty things.

Malicious bots are a problem for all opensim administrators, including walled-garden grids. They can be prevented, to a certain extent, by exo-technical solutions such as Terms of Service and real-world lawsuits. Technically speaking, the only way to keep intruders out is to run opensim inside a firewall, pretty much like all other pieces of client/server software out there. If that's an acceptable solution for your case, you should do it.

Unfortunately firewalls also keep the public out, and most opensim operators, even the ones running walled-garden grids, want to reach out to the public. In this case, opensim operators may develop additional technical obstacles for bots, similar to those we see on the Web. For example, make sure agents are being run by real people by giving them a human-challenge during the login/TP process, etc.

Every obstacle to malicious clients lowers the risk of an intruder attack. However keep this in mind: no matter how many obstacles one builds, a sufficiently skilled and motivated attacker will be able to overcome them to penetrate opensims connected to the public internet. This affects hypergrid nodes as much as walled-garden grids. In fact, it's more pervasive than that: it affects '''all''' servers (opensim, web, etc.) connected to the public internet. Fighting malicious intruders is a fact of a connected world. Fortunately, those attacks don't happen very often, or the Web would have been dead by now.

==== Web Clients ====

CopyBots are the most well-known bots for opensim-based virtual worlds, but these virtual worlds are also susceptible to attacks by regular web clients. With the current state of things, it is actually easier to copy assets with a web-based client than with a libsl-based one. The weakness is that asset servers are connected to the public internet, and the protocol for interacting with them is public.

OpenSim has some minimal guards in place to fence against these kinds of attacks. Specifically, when the inventory server receives a request for an item, it checks the session identifier of the requester. Web clients aren't logged in, so they are refused service. I don't want to expand much more on this, so not to make life easy for attackers, but let's just say that opensim has the necessary mechanisms in place to fence off web-based attackers.

=== Malicious Hosts ===

==== Actively Malicious Hosts ====

The new security threat introduced by openness, one that does not exist in closed grids, is the possibility of a user to visit a region that is running malicious code. In the current state of opensim, a malicious host can do serious damage to the user's assets. Let's see how.

Assume you have your assets in your hypergrided-standalone opensim, and you go visit another opensim that happens to be running malicious code. Here is a non-exhaustive list of vulnerabilities that you are exposed to:

* The host has your session id, so it can request your inventory items on your behalf and store copies in its local asset server. To add insult to injury, a malicious host could simply wipe out your inventory after having copied it.
* Even if the malicious host doesn't access your items by itself, every time you access items in your inventory while you are in that region, those items are cached in the region's local cache, and can be stored persistently by the malicious host.

Malicious hosts can do a lot more damage, but those two are enough to illustrate this new kind of vulnerability affecting open grids. Note that this affects all open grids, i.e. those where arbitrary people can plug-in their opensims, and not just the hypergrid.

Fortunately, there is a family of simple solutions to this problem that can be summarized as "protecting you from yourself." That proposal is described [[Hypergrid Inventory Access|here]].

==== Piracy ====

A second new security threat affecting open grids is one pertaining to commerce of virtual goods. Suppose you put something out for sale on your hypergrided opensim. A foreign user comes and buys it. What that really means is that that user will physically get a copy of the assets moved to his/her asset server, which is different from your asset server. The permissions will be whatever you define them to be, and using the regular VW client, that user can only do what you defined he/she should could do with the object, as usual. However, if the user has direct backend access to the asset and inventory servers, that person can simply modify the permissions on his/her copy. This is commonly known as '''piracy'''. (This is also a problem with programmers who have direct access to the cache that their client keeps; in this case, the only thing that needs to be done to enable piracy is for the user to actually see a texture/animation/in-world object. This does NOT allow scripts to be copied, though, since the script is only interpreted on the server and is never sent for interpretation by the client.)

This situation is the kernel of the belief that open grids are hopeless for a virtual-goods economy. DRM discussion aside, maybe they are hopeless. But then, everyone thought the web was hopeless for selling music, and look at the success of iTunes in spite of all the piracy that still exists out there. Who will be the equivalent of iTunes for virtual hair, skin and clothes?

== Hypergrid Implementation ==

=== Hyperlinks and Agent Transfers ===

When you establish a link between your opensim and another, a message is sent out to that other opensim requesting information about it; the required information includes the network information of that opensim host, and the coordinates of its first region on its local grid in the form of a region handle. For example, suppose you are linking node X.com:9000, placing it in your local map at 900, 900. That opensim runs one or more regions that likely are not in 900, 900 on their own map; suppose the first region of that opensim is at 1100, 1100. From your point of view, it doesn't matter what those other coordinates are, and you don't need to know -- that's the key to being able to decentralize the "world" as given by a 2D map; you want to place it in your map at 900, 900. The "true" position of that simulator only matters for the LL viewer, when there are teleports between your world and that other opensim. This mapping between coordinate systems is the essence of hyperlinks for opensim; it's one simple but critical thing that the hypergrid implementation does. The mapping happens on the TeleportFinish event; instead of sending the local coordinates to the viewer, the hypergrid teleport wrapper sends the remote coordinates.

When an agent teleports through that hyperlink the following happens. First, before InformRegionOfChildAgent, the local opensim notifies the remote opensim of this foreign user via the "expect_hg_user" method. That message sends along the addresses of all the servers that this user uses, i.e. user, inventory and asset servers. The remote opensim places an entry for that user in its local user profile cache but not in its user database; the foreign user information is non-persistent. After that, the teleport process is exactly the same as the normal teleport process; the only difference is that the region handles are switched between the remote region's hyperlink position on the local grid and its actual position on its grid.

In summary, the two new concepts introduced by the hypergrid are the concept of an hyperlink and the concept of a "local user" vs. "foreign user".

=== Inventory Access ===

Inventory access from abroad is done by wrapping the existing scene-inventory interactions with additional code that gets or posts inventory assets from/to the user's asset server. When inventory is accessed, the hypergrid wrapper checks if the user is foreign and, if she is, the wrapper simply brings the necessary assets from the user's asset server to the local asset cache and server; from then on, the wrapper passes the control to the existing inventory access functions. When something is added to inventory, the hypergrid wrapper is notified via an event, and posts the assets to the user's asset server. A cache of the exchanged item identifiers is maintained so that they aren't brought back over and over again.

The result is that hypergrided opensim instances end up interacting with several asset servers, instead of just one. That interaction is implemented in a straightforward manner by instantiating several GridAssetClient objects, instead of just one.

=== The Hypergrid Namespace ===

Currently, the hypergrid is implemented outside of the OpenSim namespace, so that there is complete separation between what already exists and this new behavior. It has its own namespace, HyperGrid. In it, there are 4 sub-namespaces that follow directly the software architecture of OpenSim, namely:

* '''HyperGrid.Framework''' extends OpenSim.Framework in the following manner:
** HGUserProfileData extends UserProfileData by introducing information about the user's "home", namely the home address, port and remoting port. The user's home is not that user's user service; it's the opensim that the user has defined to be her home. This is necessary for supporting the home jump (Ctrl-Shift-H).
** HGNetworkServersInfo follows the spirit of NetworkServersInfo, although it neither extends it nor uses it. For now, it's a utility class whose two main functions are to convert domain names of servers to IP addresses, and to uniformly provide the answer to the question bool IsLocalUser(...).

* '''HyperGrid.Environment''' extends OpenSim.Region.Environment.Scenes in the following manner:
** HGSceneCommunicationService extends SceneCommunicationService, overriding RequestTeleportToLocation. There are two very small but critical changes to the base method: (a) on the TeleportFinish event, we switch the region handles when the destination region is an hyperlink; (b) the connections at the end are always closed for hyperlink TPs.
** HGScene extends Scene, overriding TeleportClientHome(...). The only change to the base method is to stay away from the user server, for now, because the user service is still not completely wrapped up for foreign users. Once the user service is properly wrapped up, this class will become unnecessary.
** HGScene.Inventory is a partial class of HGScene, just like what happens in the OpenSim framework. This part of HGScene overrides some inventory-scene interaction methods, so that assets are fetched/posted from/to the user's asset server. Once that extra fetching/posting is done, these methods simply pass the ball to the base methods.
** HGAssetMapper: this is a new class specific to the hypergrid that manages the fetching and posting of assets between foreign regions where the user is and the user's asset server.

* '''HyperGrid.Protocol''' is a mashup of OpenSim.Region.Communications.*. This is the place where most of the hypergrid extension lies. One of the reasons for this is that the hypergrid communications part is doing one additional thing: it is making standalones network-able.
** HGCommunicationsStandalone extends CommuniationsLocal. Just as its base, it is a hub for the several network services available in standalone mode. The main difference is that those services are extensions of what's in OpenSim.
** HGCommunicationsGridMode extends CommunicationsManager directly. Again, it's a hub for the network services available in grid mode, those services being extensions of OpenSim.
** The cluster HGGridServices (superclass), HGGridServicesStandalone and HGGridServicesGridMode (subclasses) implements the OpenSim interfaces IGridServices and IInterRegionCommunications. The 2 subclasses are wrappers for LocalBackEndServices and OGS1GridServices, respectively. There is one common pattern throughout these classes: check if the region to talk to is an hyperlink; if it's not, simply delegate the work to LocalBackEndServices/OGS1GridServices; if it is, push the work to the base class HGGridServices. HGGridServices, in turn, does the management of hyperlink regions, and defines two additional pieces of inter-region protocol:
*** region_uuid: for linking regions
*** expect_hg_user: similar to the existing expect_user interface, but with a lot more information about the user being passed around, namely all the user's servers (inventory, asset, user, home, etc.)
** HGInventoryService extends LocalInventoryService and implements ISecureInventoryService. This class is the most obvious mashup of the pack, mixing local service access for standalone users and remote inventory access for when users are out and about. Right now, there is a fair amount of selective copy-and-paste, to stay away from the ugliness coming from OGS1InventoryService and OGS1SecureInventoryService. HGInventoryService is always a ISecureInventoryService. Its methods all follow the same pattern: check if the user is a local standalone user; if it is, pass the work to the base method (in LocalInventoryService); if it's not perform secure remote access.
** HGUserServices wraps OSG1UserServices, but it's not functional yet.

* '''HyperGrid.Modules''' is a collection of 3 region modules:
** HGWorldMapModule extends WorldMapModule. It reuses almost everything from the base class. The only small change is in RequestMapBlocks, where it tries to send Offline mapblocks to the client.
** HGStandaloneInventoryService and HGStandaloneAssetService do what their names say. They are region modules that allow access to inventory and assets for standalones, when the standalone user is out and about. In spirit, there is a lot in common between these modules and the REST inventory/asset plugin. Unfortunately, that plugin could not be used because it defines a completely different interface than that used by existing inventory and asset servers, and the access for the hypergrid must use a consistent interface.

=== Class Diagram ===

[[image:HypergridImplementation.jpg|600px|center|(Click on the image to enlarge)]]

== Installing and Running Hypergrid ==

=== Installing ===

# Checkout OpenSim, prebuild and build as normal.
# Make the following changes to your OpenSim.ini:
#* The map: '''WorldMapModule = "HGWorldMap" ''' If you didn't have this setting in your original OpenSim.ini, make sure you place it under the [Startup] section.
#* If you're running your opensim in grid mode with the UGAIM servers on other machines, you're done. If you're running in standalone and you want it to be network-able, or if you have your grid on loopback (127.0.0.1) change all the [Network] server addresses to <nowiki>"http://<external_host_name>:<http_port>"</nowiki>. See below.
# Run opensim like this: <nowiki>[mono] OpenSim.exe -hypergrid=true</nowiki>. To make sure the hypergrid is running type this on your console: '''link-region'''. If you don't hear anything back, the hypergrid is not properly installed.

Here is an example of the Network settings for a standalone:

[Network]
http_listener_port = 9300
remoting_listener_port = 9895

grid_server_url = http://example.com:9300
grid_send_key = null
grid_recv_key = null

user_server_url = http://example.com:9300
user_send_key = null
user_recv_key = null

asset_server_url = http://example.com:9300
inventory_server_url = http://example.com:9300
messaging_server_url = http://example.com:9300

Here is an example of the Network settings for a grided opensim:

[Network]
http_listener_port = 9300
remoting_listener_port = 9895

grid_server_url = http://example.com:8001
grid_send_key = null
grid_recv_key = null

user_server_url = http://example.com:8002
user_send_key = null
user_recv_key = null

asset_server_url = http://example.com:8003
inventory_server_url = http://example.com:8004
; Port 8005 reserved
messaging_server_url = http://example.com:8006

'''Important Note'''

Make sure you have a 'home' set. If your home region doesn't exist, the hyperlink TPs may not work. To set your home, go to one of your local regions and "Set Home" from the viewer.

=== Linking regions ===

On the console, type for example:

link-region <Xloc> <Yloc> osl2.nac.uci.edu 9006 OSGrid Gateway

* Use Xloc and Yloc that make sense to your world, i.e. close to your regions, but not adjacent.
* replace osl2.nac.uci.edu and 9006 with the domain name / ip address and the port of the region you want to link to

There is also some initial support for reading the links from a xml file.

By using the console command: link-region <URI>

The uri can be either the path of a local xml file or a xml file on a http server.

The format of the xml file is:

<Nini>
<Section Name="Region 1"> 
<Key Name="xloc" Value="1002"/>
<Key Name="yloc" Value="1006" />
<Key Name="externalPort" Value="9006" />
<Key Name="externalHostName" Value="osl2.nac.uci.edu" />
<Key Name="localName" Value="OSGrid-Gateway" />
</Section>
<Section Name="Region 2">
...
</Section>
...
</Nini>

'''Important Note'''

Due to a viewer [https://jira.secondlife.com/browse/SVC-2941 bug], you can only TP between regions that are no more than 4096 cells apart in any dimension. What this means in practice is that if you want to link to OSGrid, you must have your own regions reachable from the (10,000; 10,000) point on the map, which is where OSGrid is centered. Place your regions somewhere in the 8,000s or the 12,000s.

== Public Hypergrid Nodes ==

The following is a list of hypergrid-ready nodes that you can use for testing your installation and for linking your world. Please add your public node here if you wish to help build a web of opensims!

For the time being, and until the security concerns described above are addressed, we advise you to be careful about who you link to.

* '''osl2.nac.uci.edu 9006'''
The "UCI Welcome" region connected to OSGrid. It is run by Diva (Crista Lopes) on a machine owned by the University of California, Irvine. You can link to it as a way to link to OSGrid.

* '''ucigrid02.nacs.uci.edu 9000'''
A region in the UCI Grid. It is run by Diva (Crista Lopes) on a machine owned by the University of California, Irvine.

* '''grid.cyberlandia.net 9000'''
The "Cyberlandia Gw" region. http://www.cyberlandia.net Metaverso italiano 3D, more to 250 region and 1000 users. You can link to it as a way to link to Cyberlandia.

* '''hypergrid.cyberlandia.net 9000'''
The "Osgrid Gw" region connected to Cyberlandia grid http://www.cyberlandia.net. Search on map "Cyberlandia grid" You can link to it as a way to link to OSGrid.

* '''joomla-italia.net 9000
The "SNI City" region connected to SNI (Social Network Italia) grid http://www.opensim-italia.net. This grid is connected with Osgrid,Collateral World,Francogrid and Darwin

* '''collateral.opensim-italia.net 9000
[Collateral World is CLOSED and now is part of SNI]

* '''88.191.79.199 9050'''
Francogrid node, connected to "City", behind the welcome land of Francogrid "Orion"

* '''94.23.8.158 9999'''
Le Monde de Darwin node, The Lost of Darwin http://www.LeMondedeDarwin.com
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* '''grid.k-grid.com 9000'''
K-grid, [http://k-grid.com the Kool grid for the Kool KidZ] . Feel free to visit us. The main Gateway is located at 3700,3700 so take that in account before any HyperJump

* '''metropolis.hypergrid.org 9000'''
The Region "Center-World" (at 1000:1000) connected to the METROPOLIS-Grid http://metropolis.hypergrid.org . German Grid with a lot of free Content and free SIM-hosting. Connected via HG to the most of the Grids listed here.

* '''ascent.bluewallgroup.com 9910'''
This region is in a good proximity @ (6000,6000) for intermediate jumps to OSGrid from grids in the (2000,2000) range, or any region within 4096 units. [[Image:Hypernaut 001.png|150px|none|thumb|Get your Hypernaut here :)]]

* '''sim.thestudyofracialism.org 9000'''
TSOR1 is a stand-alone sim (at 4000,4000) owned by '''Backintyme Publishing'''. It connects to most of the other downrange sites listed here. Although currently sparse, the sim is eventually intended for an SL discussion-group's migration from SL to OS.

* '''pc.backintyme.com 9100'''
TSOR2 is a small teleport relay island (at 8000,8000), also owned by '''Backintyme Publishing''', intended for jumps to the vicinity of OSGrid. It is linked to most of the uprange sites listed here.

* '''http://myopengrid.com 9000'''
Myopengrid is connected to osl2.nac.uci.edu "Osgrid Gateway" our regions are at (7000,7000).

* '''cuonsim1.de 9300'''
Cuon-Grid is a little grid and has some Main Sims with linux themes, Regions are at (10000,10000),server are in Germany.To login in to the grid use this http://sim-linuxmain.org:8081/CuonGrid/index.html. There are free sims for testing.

* '''metaversesims.net 9014'''
Standalone mode - 6 regions at (9000,9000) - linked to the grids shown below
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