i2p.www/i2p2www/pages/site/docs/api/bob.html

{% extends "global/layout.html" %}
{% block title %}{{ _('BOB - Basic Open Bridge') }}{% endblock %}
{% block lastupdated %}{% trans %}November 2015{% endtrans %}{% endblock %}
{% block content %}
<h2>Language libraries for the BOB API</h2>
<ul>
<li>Go - <a href="https://bitbucket.org/kallevedin/ccondom">ccondom</a></li>
<li>Python - <a href="http://{{ i2pconv('git.repo.i2p') }}/w/i2py-bob.git">i2py-bob</a></li>
<li>Twisted - <a href="https://pypi.python.org/pypi/txi2p">txi2p</a></li>
</ul>

<h2>{% trans %}Technical differences from SAM (for the better?){% endtrans %}</h2>

<p>{% trans -%}
BOB has separate command and data channels. 
One, an application command channel socket to router to configure.
Two, the application data sockets to/from router that carry only data.
The command channel is only needed for making or setting the initial
destination key, and to set the destination key to port bindings. 
All connections run in parallel.
{%- endtrans %}</p>

<p>{% trans -%}
SAM has one connection that does everything, and you need to parse every packet.
{%- endtrans %}</p>

<p>{% trans -%}
BOB does not hold keypair values, nor does the router.
Your application holds the keypair values. 
This is to reduce any extra complexity in the router code, it also adds to
your privacy.
{%- endtrans %}</p>

<p>{% trans -%}
SAM router stores every keypair you ever make.
{%- endtrans %}</p>

<p>{% trans -%}
Those are the important differences.
{%- endtrans %}</p>

<p>{% trans -%}
<code>KEYS</code> = keypair public+private, these are BASE64
{%- endtrans %}</p>
<p>{% trans -%}
<code>KEY</code> = public key, also BASE64
{%- endtrans %}</p>
<p>{% trans -%}
<code>ERROR</code> as is implied returns the message <code>"ERROR "+DESCRIPTION+"\n"</code>, where the <code>DESCRIPTION</code> is what went wrong.
{%- endtrans %}</p>
<p>{% trans -%}
<code>OK</code> returns <code>"OK"</code>, and if data is to be returned, it is on the same line. <code>OK</code> means the command is finished.
{%- endtrans %}</p>
<p>{% trans -%}
<code>DATA</code> lines contain information that you requested. There may be multiple <code>DATA</code> lines per request.
{%- endtrans %}</p>

<p>{% trans -%}
<b>NOTE:</b> The help command is the ONLY command that has an exception to
the rules... it can actually return nothing! This is intentional, since
help is a HUMAN and not an APPLICATION command.
{%- endtrans %}</p>

<p>{% trans -%}
<b>PLEASE NOTE:</b>
For CURRENT details on the commands PLEASE use the built-in help command. 
Just telnet to localhost 2827 and type help and you can get full documentation on each command. 
{%- endtrans %}</p>

<p>{% trans -%}
Commands never get obsoleted or changed, however new commands do get added from time to time.
{%- endtrans %}</p>

<p>{% trans -%}
Here are the commands we have as of this writing:
{%- endtrans %}</p>

{% highlight lang='text' %}
{{ _('COMMAND') }}     {{ _('OPERAND') }}                             {{ _('RETURNS') }}
help        (optional command to get help on)   NOTHING or OK and description of the command
clear                                           ERROR or OK
getdest                                         ERROR or OK and KEY
getkeys                                         ERROR or OK and KEYS
getnick     tunnelname                          ERROR or OK
inhost      hostname or IP address              ERROR or OK
inport      port number                         ERROR or OK
list                                            ERROR or DATA lines and final OK
lookup      hostname                            ERROR or OK and KEY
newkeys                                         ERROR or OK and KEY
option      key1=value1 key2=value2...          ERROR or OK
outhost     hostname or IP address              ERROR or OK
outport     port number                         ERROR or OK
quiet                                           ERROR or OK
quit                                            OK and terminates the command connection
setkeys     KEYS                                ERROR or OK and KEY
setnick     tunnel nickname                     ERROR or OK
show                                            ERROR or OK and information
showprops                                       ERROR or OK and information
start                                           ERROR or OK
status      tunnel nickname                     ERROR or OK and information
stop                                            ERROR or OK
verify      KEY                                 ERROR or OK
visit                                           OK, and dumps BOB's threads to the wrapper.log
zap                                             nothing, quits BOB
{% endhighlight %}

<p>{% trans -%}
Once set up, all TCP sockets can and will block as needed, and there is no need for any 
additional messages to/from the command channel. This allows the router to pace the
stream without exploding with OOM like SAM does as it chokes on attempting to shove 
many streams in or out one socket -- that can't scale when you have alot of connections!
{%- endtrans %}</p>

<p>{% trans -%}
What is also nice about this particular interface is that writing anything to interface 
to it, is much much easier than SAM. There is no other processing to do after the set up.
It's configuration is so simple, that very simple tools, such as nc (netcat) can be used 
to point to some application. The value there is that one could schedule up and down times 
for an application, and not have to change the application to do that, or to even have 
to stop that application. Instead, you can literally "unplug" the destination, and 
"plug it in" again. As long as the same IP/port addresses and destination keys are used 
when bringing the bridge up, the normal TCP application won't care, and won't notice.
It will simply be fooled -- the destinations are not reachable, and that nothing is coming in.
{%- endtrans %}</p>

<p>{% trans -%}
For the following example, we'll setup a very simple local loopback connection, 
with two destinations. Destination "mouth" will be the CHARGEN service from 
the INET superserver daemon. Destination "ear" will be a local port that you
can telnet into, and watch the pretty ASCII test puke forth.
{%- endtrans %}</p>

{% highlight lang='text' %}
{% trans %}EXAMPLE SESSION DIALOGUE -- simple telnet 127.0.0.1 2827 works{% endtrans %}
A = {{ _('Application') }}
C = {% trans %}BOB's Command response.{% endtrans %}

{{ _('FROM') }} 	{{ _('TO') }}	{{ _('DIALOGUE') }}
A	C	setnick mouth
C	A	OK Nickname set to mouth
A	C	newkeys
C	A	OK ZMPz1zinTdy3~zGD~f3g9aikZTipujEvvXOEyYfq4Su-mNKerqG710hFbkR6P-xkouVyNQsqWLI8c6ngnkSwGdUfM7hGccqBYDjIubTrlr~0g2-l0vM7Y8nSqtFrSdMw~pyufXZ0Ys3NqUSb8NuZXpiH2lCCkFG21QPRVfKBGwvvyDVU~hPVfBHuR8vkd5x0teMXGGmiTzdB96DuNRWayM0y8vkP-1KJiPFxKjOXULjuXhLmINIOYn39bQprq~dAtNALoBgd-waZedYgFLvwHDCc9Gui8Cpp41EihlYGNW0cu0vhNFUN79N4DEpO7AtJyrSu5ZjFTAGjLw~lOvhyO2NwQ4RiC4UCKSuM70Fz0BFKTJquIjUNkQ8pBPBYvJRRlRG9HjAcSqAMckC3pvKKlcTJJBAE8GqexV7rdCCIsnasJXle-6DoWrDkY1s1KNbEVH6i1iUEtmFr2IHTpPeFCyWfZ581CAFNRbbUs-MmnZu1tXAYF7I2-oXTH2hXoxCGAAAA
{% endhighlight %}

<p><b>{% trans -%}
MAKE NOTE OF THE ABOVE DESTINATION KEY, YOURS WILL BE DIFFERENT!
{%- endtrans %}</b></p>

{% highlight lang='text' %}
{{ _('FROM') }}    {{ _('TO') }}    {{ _('DIALOGUE') }}
A       C     outhost 127.0.0.1
C       A     OK outhost set
A       C     outport 19
C       A     OK outbound port set
A       C     start
C       A     OK tunnel starting
{% endhighlight %}

<p>{% trans -%}
At this point, there was no error, a destination with a nickname of "mouth" 
is set up. When you contact the destination provided, you actually connect 
to the <code>CHARGEN</code> service on <code>19/TCP</code>.
{%- endtrans %}</p>

<p>{% trans -%}
Now for the other half, so that we can actually contact this destination.
{%- endtrans %}</p>

{% highlight lang='text' %}
{{ _('FROM') }}    {{ _('TO') }}      {{ _('DIALOGUE') }}
A       C       setnick ear
C       A       OK Nickname set to ear
A       C       newkeys
C       A       OK 8SlWuZ6QNKHPZ8KLUlExLwtglhizZ7TG19T7VwN25AbLPsoxW0fgLY8drcH0r8Klg~3eXtL-7S-qU-wdP-6VF~ulWCWtDMn5UaPDCZytdGPni9pK9l1Oudqd2lGhLA4DeQ0QRKU9Z1ESqejAIFZ9rjKdij8UQ4amuLEyoI0GYs2J~flAvF4wrbF-LfVpMdg~tjtns6fA~EAAM1C4AFGId9RTGot6wwmbVmKKFUbbSmqdHgE6x8-xtqjeU80osyzeN7Jr7S7XO1bivxEDnhIjvMvR9sVNC81f1CsVGzW8AVNX5msEudLEggpbcjynoi-968tDLdvb-CtablzwkWBOhSwhHIXbbDEm0Zlw17qKZw4rzpsJzQg5zbGmGoPgrSD80FyMdTCG0-f~dzoRCapAGDDTTnvjXuLrZ-vN-orT~HIVYoHV7An6t6whgiSXNqeEFq9j52G95MhYIfXQ79pO9mcJtV3sfea6aGkMzqmCP3aikwf4G3y0RVbcPcNMQetDAAAA
A       C       inhost 127.0.0.1
C       A       OK inhost set
A       C       inport 37337
C       A       OK inbound port set
A       C       start
C       A       OK tunnel starting
A       C       quit
C       A       OK Bye!
{% endhighlight %}

<p>{% trans -%}
Now all we need to do is telnet into 127.0.0.1, port 37337,
send the destination key or host address from addressbook we want to contact.
In this case, we want to contact "mouth", all we do is paste in the
key and it goes.
{%- endtrans %}</p>

<p>{% trans -%}
<b>NOTE:</b> The "quit" command in the command channel does NOT disconnect the tunnels like SAM.
{%- endtrans %}</p>

{% highlight lang='text' %}
$ telnet 127.0.0.1 37337
Trying 127.0.0.1...
Connected to 127.0.0.1.
Escape character is '^]'.
ZMPz1zinTdy3~zGD~f3g9aikZTipujEvvXOEyYfq4Su-mNKerqG710hFbkR6P-xkouVyNQsqWLI8c6ngnkSwGdUfM7hGccqBYDjIubTrlr~0g2-l0vM7Y8nSqtFrSdMw~pyufXZ0Ys3NqUSb8NuZXpiH2lCCkFG21QPRVfKBGwvvyDVU~hPVfBHuR8vkd5x0teMXGGmiTzdB96DuNRWayM0y8vkP-1KJiPFxKjOXULjuXhLmINIOYn39bQprq~dAtNALoBgd-waZedYgFLvwHDCc9Gui8Cpp41EihlYGNW0cu0vhNFUN79N4DEpO7AtJyrSu5ZjFTAGjLw~lOvhyO2NwQ4RiC4UCKSuM70Fz0BFKTJquIjUNkQ8pBPBYvJRRlRG9HjAcSqAMckC3pvKKlcTJJBAE8GqexV7rdCCIsnasJXle-6DoWrDkY1s1KNbEVH6i1iUEtmFr2IHTpPeFCyWfZ581CAFNRbbUs-MmnZu1tXAYF7I2-oXTH2hXoxCGAAAA
 !"#$%&amp;'()*+,-./0123456789:;&lt;=&gt;?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcdefg
!"#$%&amp;'()*+,-./0123456789:;&lt;=&gt;?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcdefgh
"#$%&amp;'()*+,-./0123456789:;&lt;=&gt;?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcdefghi
#$%&amp;'()*+,-./0123456789:;&lt;=&gt;?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcdefghij
$%&amp;'()*+,-./0123456789:;&lt;=&gt;?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcdefghijk
...
{% endhighlight %}
<p>{% trans -%}
After a few virtual miles of this spew, press <code>Control-]</code>
{%- endtrans %}</p>
{% highlight lang='text' %}
...
cdefghijklmnopqrstuvwxyz{|}~ !"#$%&amp;'()*+,-./0123456789:;&lt;=&gt;?@ABCDEFGHIJK
defghijklmnopqrstuvwxyz{|}~ !"#$%&amp;'()*+,-./0123456789:;&lt;=&gt;?@ABCDEFGHIJKL
efghijklmnopqrstuvwxyz{|}~ !"#$%&amp;'()*+,-./0123456789:;&lt;=
telnet&gt; c
Connection closed.
{% endhighlight %}

<p>{% trans -%}
Here is what happened...
{%- endtrans %}</p>
{% highlight lang='text' %}
telnet -&gt; ear -&gt; i2p -&gt; mouth -&gt; chargen -.
telnet &lt;- ear &lt;- i2p &lt;- mouth &lt;-----------'
{% endhighlight %}

<p>{% trans -%}
You can connect to EEPSITES too!
{%- endtrans %}</p>

{% highlight lang='text' %}
$ telnet 127.0.0.1 37337
Trying 127.0.0.1...
Connected to 127.0.0.1.
Escape character is '^]'.
i2host.i2p
GET / HTTP/1.1

HTTP/1.1 200 OK
Date: Fri, 05 Dec 2008 14:20:28 GMT
Connection: close
Content-Type: text/html
Content-Length: 3946
Last-Modified: Fri, 05 Dec 2008 10:33:36 GMT
Accept-Ranges: bytes

&lt;html&gt;
&lt;head&gt;
  &lt;title&gt;I2HOST&lt;/title&gt;
  &lt;link rel="shortcut icon" href="favicon.ico"&gt;
&lt;/head&gt;
...
&lt;a href="http://sponge.i2p/"&gt;--Sponge.&lt;/a&gt;&lt;/pre&gt;
&lt;img src="/counter.gif" alt="!@^7A76Z!#(*&amp;amp;%"&gt; visitors. &lt;/body&gt;
&lt;/html&gt;
Connection closed by foreign host.
$
{% endhighlight %}

<p>{% trans -%}
Pretty cool isn't it? Try some other well known EEPSITES if you like, nonexistent ones, 
etc, to get a feel for what kind of output to expect in different situations. 
For the most part, it is suggested that you ignore any of the error messages. 
They would be meaningless to the application, and are only presented for human debugging.
{%- endtrans %}</p>

<p>{% trans -%}
Let's put down our destinations now that we are all done with them.
{%- endtrans %}</p>

<p>{% trans -%}
First, lets see what destination nicknames we have.
{%- endtrans %}</p>

{% highlight lang='text' %}
{{ _('FROM') }} 	{{ _('TO') }}	{{ _('DIALOGUE') }}
A	C	list
C	A	DATA NICKNAME: mouth STARTING: false RUNNING: true STOPPING: false KEYS: true QUIET: false INPORT: not_set INHOST: localhost OUTPORT: 19 OUTHOST: 127.0.0.1
C	A	DATA NICKNAME: ear STARTING: false RUNNING: true STOPPING: false KEYS: true QUIET: false INPORT: 37337 INHOST: 127.0.0.1 OUTPORT: not_set OUTHOST: localhost
C	A	OK Listing done
{% endhighlight %}

<p>{% trans -%}
Alright, there they are. First, let's remove "mouth".
{%- endtrans %}</p>

{% highlight lang='text' %}
{{ _('FROM') }} 	{{ _('TO') }}	{{ _('DIALOGUE') }}
A	C	getnick mouth
C	A	OK Nickname set to mouth
A	C	stop
C	A	OK tunnel stopping
A	C	clear
C	A	OK cleared
{% endhighlight %}

<p>{% trans -%}
Now to remove "ear", note that this is what happens when you type too fast,
and shows you what typical ERROR messages looks like.
{%- endtrans %}</p>

{% highlight lang='text' %}
{{ _('FROM') }} 	{{ _('TO') }}	{{ _('DIALOGUE') }}
A	C	getnick ear
C	A	OK Nickname set to ear
A	C	stop
C	A	OK tunnel stopping
A	C	clear
C	A	ERROR tunnel is active
A	C	clear
C	A	OK cleared
A	C	quit
C	A	OK Bye!
{% endhighlight %}

<p>{% trans -%}
I won't bother to show an example of the receiver end of a bridge
because it is very simple. There are two possible settings for it, and
it is toggled with the "quiet" command.
{%- endtrans %}</p>

<p>{% trans -%}
The default is NOT quiet, and the first data to come into your
listening socket is the destination that is making the contact. It is a
single line consisting of the BASE64 address followed by a newline.
Everything after that is for the application to actually consume.
{%- endtrans %}</p>

<p>{% trans -%}
In quiet mode, think of it as a regular Internet connection. No
extra data comes in at all. It's just as if you are plain connected to
the regular Internet. This mode allows a form of transparency much like
is available on the router console tunnel settings pages, so that you
can use BOB to point a destination at a web server, for example, and
you would not have to modify the web server at all.
{%- endtrans %}</p>

<p>{% trans -%}
The advantage with using BOB for this is as discussed
previously. You could schedule random uptimes for the application,
redirect to a different machine, etc. One use of this may be something
like wanting to try to goof up router-to-destination upness guessing.
You could stop and start the destination with a totally different
process to make random up and down times on services. That way you
would only be stopping the ability to contact such a service, and not
have to bother shutting it down and restarting it. You could redirect
and point to a different machine on your LAN while you do updates, or
point to a set of backup machines depending on what is running, etc,
etc. Only your imagination limits what you could do with BOB.
{%- endtrans %}</p>
{% endblock %}