Login-on-connect documentation
Last updated 22 Jun 2004 by Vampire-

1. This feature is experimental.

2. The main point is to allow clients to log in to a service bot (i.e., X)
*before* being announced to the network. Otherwise, a combination of a
malicious user, /ISON, /USERIP and low latency can reveal it's real host/IP
before he gets a chance to log in and set himself +x

3. Client<->Server changes:
~~~~~~~~~~~~~~~~~~~~~~~~~~~
The PASS command now has the following syntax:

PASS [optional I-line password] <bot nick> <username> :<passphrase>

If the client sends such a password message, after sending NICK,
USER and PONG, it's username/passphrase are sent to the specified bot
for validation, while holding the client in the 'registration' state.
If the authentication succeeds, the client's account and umode +x are set,
after which he is introduced to the network, continuing the regular connect
phase. If authentication fails (or the bot is not on the network), the user
is given a chance to retry (he can do this by sending another PASS command),
or to disconnect from the server. If he wishes to connect without a hidden
hostmask, he can send a PASS command with no parameters.

Update: For buggy clients that send ("PASS :%s", whatever-the-user-typed)
and thus are incapable of sending multiple arguments, there's a hack in
mr_pass that splits up the argument if the first character is a ':'.
This way users might use ":bot user :pass phrase" in their clients.
The example above would be, in raw form:

PASS ::[optional I-line password] <bot nick> <username> :<passphrase>

4. Server<->Server changes:
~~~~~~~~~~~~~~~~~~~~~~~~~~~
The ACCOUNT message now has the following syntax:

Auth check: 
<client's server numeric> AC <bot's numeric> C <request-id> <username> :<passphrase>
Servers send this message to request a service bot to authenticate the client.
<request-id> is not processed neither by the servers along the way nor the
service bot. Currently this is:
	 '.' <fd> '.' <cookie>
The inital '.' makes sure that the ID is not a valid integer, which is part of
the hack required to support old-style ACCOUNT messages. The cookie is used to
validate replies, since the user might disconnect and the fd be reused before
the reply comes back from the service. Hubs propagate this message as-is
towards the service bot, not unlike PRIVMSG.

Auth reply:
<bot's server numeric> AC <client's server numeric> A|D <request-id>
Service bots send this in reply to an 'auth check' message from a server.
"A" stands for "accepted", "D" for "denied". Again, hubs will have
to proagate this message back to the client's server.

Remote auth:
<bot's server numeric> AC <client numeric> R <account> [<timestamp>]
This is the current message used by service bots to announce the network
that a user has logged in. The old format is still supported:
<bot's server numeric> AC <client numeric> <account> [<timestamp>]

5. ircu code changes
~~~~~~~~~~~~~~~~~~~~
A new feature, FEAT_LOGIN_ON_CONNECT (default FALSE) will specify whether
ircu will honour the login scheme as specified above for the PASS command.
ircu will route ACCOUNT messages anyway, regardless of this feature's value.