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+BIBOUMI 1 "2013-11-21"
+======================
+
+NAME
+----
+
+Bbiboumi - XMPP gateway to IRC
+
+SYNOPSIS
+--------
+
+`biboumi` [`config_file`]
+
+DESCRIPTION
+-----------
+
+Biboumi is an XMPP gateway that connects to IRC servers and translates
+between the two protocols. It can be used to access IRC channels using any
+XMPP client as if these channels were XMPP MUCs.
+
+OPTIONS
+-------
+
+Available options:
+
+`config_filename`
+
+  Specify the file to read for configuration. See *CONFIG* section for more
+  details on its content.
+
+CONFIG
+------
+
+The configuration file uses a simple format of the form
+`"option=value"`. Here is a description of each possible option:
+
+`hostname` (mandatory)
+
+  The hostname served by the XMPP gateway.  This domain must be configured in
+  the XMPP server as an external component.  See the manual for your XMPP
+  server for more information.
+
+`password` (mandatory)
+
+  The password used to authenticate the XMPP component to your XMPP server.
+  This password must be configured in the XMPP server, associated with the
+  external component on *hostname*.
+
+USAGE
+-----
+
+When started, biboumi connects, without encryption (see *SECURITY*), to the
+local XMPP server on the port `5347` and provides the configured password to
+authenticate.  Biboumi then serves the configured `hostname`, this means
+that all XMPP stanza with a `to` JID on that domain will be sent to biboumi,
+and biboumi will send only send messages coming from this hostname.
+
+When an user joins an IRC channel on an IRC server (see *Join an IRC
+channel*), biboumi connects to the remote IRC server, sets the user’s nick
+as requested, and then tries to join the specified channel.  If the same
+user subsequently tries to connect to an other channel on the same server,
+the same IRC connection is used.  If, however, an other user wants to join
+an IRC channel on that same IRC server, biboumi opens a new connection to
+that server.  Biboumi connects once to each IRC server, for each user on it.
+
+### Addressing
+
+IRC entities are represented by XMPP JIDs.  The domain part of the JID is
+the domain served by biboumi, and the local part depends on the concerned
+entity.
+
+IRC channels and IRC users JIDs have a localpart formed like this:
+`name`, the `'%'` separator and the `irc_server`.
+
+For an IRC channel, the name starts with `'&'`, `'#'`, `'+'`
+or `'!'`. Some other gateway implementations, as well as some IRC
+clients, do not require them to be started by one of these characters,
+adding an implicit `'#'` in that case.  Biboumi does not do that because
+this gets confusing when trying to understand the difference between
+*foo*, *#foo*, and *##foo*.
+
+If the name starts with any other character, this represents an IRC user.
+
+### Join an IRC channel
+
+To join an IRC channel `#foo` on the IRC server `irc.example.com`,
+join the XMPP MUC `#foo%irc.example.com@hostname`.
+
+### Channel messages
+
+On XMPP, unlike on IRC, the displayed order of the messages is the same for
+all participants of a MUC.  Biboumi can not however provide this feature, as
+it cannot know whether the IRC server has received and forwarded the
+messages to other users.  This means that the order of the messages
+displayed in your XMPP may not be the same than the order on other IRC
+users’.
+
+### Nicknames
+
+On IRC, nicknames are server-wide.  This means that one user only has one
+single nickname at one given time on all the channels of a server. This is
+different from XMPP where an user can have a different nick on each MUC,
+even if these MUCs are on the same server.
+
+This means that the nick you choose when joining your first IRC channel on a
+given IRC server will be your nickname in all other channels that you join
+on that same IRC server.
+If you explicitely change your nickname on one channel, your nickname will
+be changed on all channels on the same server as well.
+
+### Private messages
+
+Private messages are handled differently on IRC and on XMPP.  On IRC, you
+talk directly to one server-user: toto on the channel #foo is the same user
+than toto on the channel #bar (as long as these two channels are on the same
+IRC server).  Using biboumi, there is no way to receive a message from a
+room participant (from a jid like #test%irc.example.com/nickname).  Instead,
+private messages are received from and sent to the user (using a jid like
+nickname%irc.example.com).  For conveniance and compatibility with XMPP
+clients sending private messages to the MUC participants, a message sent to
+#chan%irc.example.com@irc.example.net/Nickname will be redirected to
+Nickname%irc.example.com@irc.example.net, although this is not the prefered
+way to do it.
+
+### Notices
+
+Notices are received exactly like private messages.  It is not possible to
+send a notice.
+
+### Kicks and bans
+
+Kicks are transparently translated from one protocol to another.  However
+banning an XMPP participant has no effect.  To ban an user you need to set a
+mode +b on that user nick or host (see *MODES*) and then kick it.
+
+### Encoding
+
+On XMPP, the encoding is always `UTF-8`, whereas on IRC the encoding of
+each message can be anything.
+
+This means that biboumi has to convert everything coming from IRC into UTF-8
+without knowing the encoding of the received messages.  To do so, it checks
+if each message is UTF-8 valid, if not it tries to convert from
+`iso_8859-1` (because this appears to be the most common case, at least
+on the channels I visit) to `UTF-8`.  If that conversion fails at some
+point, a placeholder character `'�'` is inserted to indicate this
+decoding error.
+
+Messages are always sent in UTF-8 over IRC, no conversion is done in that
+direction.
+
+### IRC modes
+
+One feature that doesn’t exist on XMPP but does on IRC is the `modes`.
+Although some of these modes have a correspondance in the XMPP world (for
+example the `+o` mode on an user corresponds to the `moderator` role
+in XMPP), it is impossible to map all these modes to an XMPP feature.  To
+circumvent this problem, biboumi provides a raw notification when modes are
+changed, and lets the user change the modes directly.
+
+To change modes, simply send a message starting with “`/mode`” followed
+by the modes and the arguments you want to send to the IRC server.  For
+example “/mode +aho louiz”.  Note that your XMPP client may
+inteprete messages begining with “/” like a command.  To actually send a
+message starting with a slash, you may need to start your message with
+“//mode” or “/say /mode”, depending on your client.
+
+When a mode is changed, the user is notified by a message coming from the
+MUC bare JID, looking like “Mode #foo [+ov] [toto tutu]”.  In addition, if
+the mode change can be translated to an XMPP feature, the user will be
+notified of this XMPP event as well. For example if a mode “+o toto” is
+received, then toto’s role will be changed to moderator.  The mapping
+between IRC modes and XMPP features is as follow:
+
+`+o`
+
+  Sets the participant’s role to `moderator`.
+
+`+a`
+
+  Sets the participant’s role to `admin`.
+
+`+v`
+
+  Sets the participant’s affiliation to `member`.
+
+SECURITY
+--------
+
+Biboumi does not provide any encryption mechanism: connection to the XMPP
+server MUST be made on localhost.  The XMPP server is not supposed to accept
+non-local connection from components, thus encryption is useless.  IRC
+SSL/TLS is also not implemented although this could be useful for some
+users, this is however not a high priority feature.
+
+Biboumi also does not check if JIDs are properly formatted using nodeprep.
+This must be done by the XMPP server to which biboumi is directly connected.
+
+AUTHORS
+-------
+
+Written by Florent Le Coz