Intermud-3_ a Proposal for the Future

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Initial protocol design by:

Greg Stein ([email protected])

John Viega ([email protected])

Tim Hollebeek ([email protected])

Please forward discussion to the Intermud mailing list at [email protected]. You may subscribe by mailing

[email protected]. Place "subscr i be i nter mud" in the body.

This document details a proposal for a future generation of Intermud protocols. It is designed to use the high

level communication facilities provided by the MudOS LP driver. Other drivers may be capable of handling

the communication protocol, but this proposal does not focus on them. See Other Drivers for a possible

scheme to include them into the Intermud as defined by this proposal.

This document has the following sections:

Contributors and Implementors : lists the contributors to this specification and people who have createdI3 implementations (for public or private release)

Logical Network Layout : describes how the muds connect to each other

Packet Format : describes the basic format of all packets

Services : describes the services available

Support Packets : describes additional packet types for maintainance purposes

OOB Protocols : describes the protocols used for OOB communications

Router Design : describes the design of the routers

Other Drivers/Mudlibs : describes an approach that could be used to include non-MudOS drivers

Error Summary : quick summary of the error codes used

Packet Types Summary : quick summary of the packets that are usedCompressed Mode : describes a scheme for compressing the transmitted data

Change Log : lists recent changes to the specification

Many people have contributed to this specification. This is an attempt to list those people who have helped in

some way or another. Also, there are a number of implementations out there now. This list should help with

locating resources for picking up an implementation for for finding people who have an implementation

similar to your needs.

Contributors:

As mentioned at the head of this page, the core designers of this protocol were:

Deathblade (Greg Stein, [email protected])

Rust (John Viega, [email protected])

Beek (Tim Hollebeek, [email protected])

Descartes (George Reese,[email protected])

mud-3: a Proposal for The Future http://mud.stack.nl/intermud/interm

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Descartes contributed in a number of areas, particularly as one of the pioneer implementors after the

initial development by the Lima Mudlib team.

Deathknight (Jesse McClusky, [email protected])

Deathknight was the original contributor of the central router-based, backbone design of the current I3

system.

There are, of course, many other contributors who offered input both at the conference in February '95 and on

the intermud mailing list. Their omission is not by design, but because informartion wasn't available at the

time of this writing (they didn't provide info).

Implementations:

The Lima Mudlib contains an implementation of the Intermud-3 system (written by Deathblade). This

was the first implementation to exist and is one of the few that is readily and publically available for

use by other systems. It was implemented for the MudOS v22 driver. It is publically available at:

ftp://ftp.imaginary.com/lib/LIMA

TheNightmare Object Library also contains an implementation of the Intermud-3 system (written by

Descartes). This implementation is also one of the oldest around, originating soon after the Lima

version and first appearing in the release of Nightmare IV.

The Intermud-3 system for Nightmare (and Foundation) has also been pulled out into its own package,

available at: ftp://ftp.imaginary.com/pub/LPC/etc/Intermud3.tar.gz.

Terry (Terry Penn, [email protected]) has created two implementations of the Intermud-3 system.

One is for Shadow's Edge running LPMUD 3.2.1@122

Another for MudOS v22a18

Both of these are running on custom mudlibs and are not generally available.

Logic (Edward Marshall, [email protected]) has written an implementation for LPmud 3.2.1 for the

private mudlib EOTSlib. He has potential plans for a public release of the I3 package.

Skylight (Patrick Li,[email protected])

Hanzou (James Donald Jr., [email protected])

They have written a version for LPmud 3.2.1@98 (or later). The package is primarily aimed for 2.4.5

mudlibs and is available at: ftp://ftp.netcom.com/pub/ja/jamesd/lpmud/amylaar-intermud3-latest.tar.gz

Deathblade and Cowl (Hal Schechner, [email protected]) designed and implementated the

Intermud-3 router currently in use at athens.imaginary.com.

As always, there are many others out there, but they have not submitted information yet for inclusion here.

The logical network of muds is organized into a set of fully connected routers each acting as a hub for an

arbitrary set of muds.

A mud has a "preferred" router, but will be told and will record information about all routers in existence (for


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failover in case the preferred is down). A mud's preferred router may be changed programatically to handle

load balancing among routers.

The routers open and maintain TCP sessions (using MudOS's "MUD" mode) to each of the other routers

(fully connected network). Each router will hold a list of all muds within the intermud and which router the

mud is connected to.

An active TCP session (in MUD mode) is maintained between a mud and its router. The mud is responsibile

for opening (see the startup-req-2 packet), maintaining, reconnecting, and shutting down this session. A

graceful exit will cause the router to propogate information about the "down" state of the mud to the other

routers and muds on the intermud. A dropped connection will wait 5 minutes before delivering "down" state

notification (this 5 minutes is provided for the mud to reconnect). A mud is removed after 7 days of being in

the down state.

The network of TCP sessions between the routers and muds will be used for "in band" transmissions. The

data carried over these connections will be limited to "fast response" messages. Some services will be carried

off of this network and are called "out of band" (OOB) transmissions.

Each mud will listen at a TCP port for incoming connections for processing OOB transmissions. At themoment, the services that use the OOB transmissions are mail, news, and file transfers. Connections will be

opened as needed and closed when the transmission completes.

Lastly, each mud may maintain a UDP port for some specific OOB transmissions. At the moment, though,

there are no UDP-based OOB services, so this port is typically not opened.

MUD Naming

For proper identification within the Intermud network, muds must use a canonical naming system. The

canonical name is defined to be the mud's actual name (properly capitalized, with spaces, etc). Examples:

Quendor,Idea Exchange. These names will be used in the mudlist and in all packet routing. The case is

significant, although the routers may (?) disallow two muds with the same name, but with different casing.

Routers will have names assigned to them; there are a few cases where a router must be referenced. routers

will be distinguished from muds with a leading asterisk (such as *nightmare). Muds may not define a name

with a leading asterisk if they wish to be a part of the Intermud.

Transmissions are LPC arrays with a predefined set of six initial elements: ( { type, ttl, originator

mudname, originator username, target mudname, target username, . . . }) .

type describes the type of the packet. See Packet Types for a summary of the packet types used in this

protocol.

ttl is the packet's Time To Live (TTL). This is similar to an IP packet's TTL - it specifies the number of hops

left to a packet. This may not be absolutely necessary, but provides a mechanism to handle the case where the

routers mis-route a packet into an endless loop. Eventually, it will time out and be removed from the network.


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originator mudname is used to indicate the mud where the packet originated. If the packet cannot be

delivered for some reason, this mud will be notified, if possible.

originator username is used to indicate the user that triggered the delivery of the packet. If the mud itself sent

the packet (e.g. mail delivery or shutdown notification), then the username will be 0. The username should be

in lower-case.

target mudname is used to route the packet to the appropriate destination mud. Zero is used to indicate

broadcast packets.

target username is used to route the packet to a particular user on a remote mud. The username may be 0 if

the packet is targeted for the mud itself rather than a specific user. This should always be in lower-case. The

target mud will attempt to find the user with whatever appropriate means.

Many packets will specify a visname. This is a user's "visible" name - the name which should be displayed to

other users. Typically, this is equivalent to the username with altered capitalization, but may actually be quite

arbitrary with respect to the username.

There are eleven services covered by this proposal:

tell : send a message to a user on a remote mud

emoteto : send an emote to a user on a remote mud

who : get a list of users on a remote mud

finger: get information about a particular user on a remote mud

locate : locate a player on a remote mud(s)

channel : send a string/emote/soul between mudsnews : propogate news posts between muds

mail : propogate mail items between muds

file : transfer a file between muds

auth : perform mud or user authentication

ucache : cache information about remote users

Service: tell

The originator will deliver the following packet to the target mud over the in-band network (to its router):

( {( s t r i ng) " t el l " ,( i nt ) 5,( st r i ng) ori gi nator_ mudname,( st r i ng) or i gi nat or _user name,( st r i ng) t arget_mudname,( st r i ng) t ar get _username,( st r i ng) or i g_vi sname,( st r i ng) message

})

At the target mud, the message will be delivered to target_username. The orig_visname is told to the


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target_username to indicate who sent the message; it is usually combined with the originator_mudname as:

spr i nt f ( "%s@%s" , or i g_vi sname, or i gi nator_mudname) .

The target_username should be lower-cased by the originating mud.

If the router fails to deliver the packet for some reason, it will return an errorpacket.

Service: emoteto

The originator will deliver the following packet to the target mud over the in-band network (to its router):

( {( st r i ng) "emot et o",( i nt ) 5,( st r i ng) ori gi nator_ mudname,( st r i ng) or i gi nat or _user name,( st r i ng) t arget_mudname,( st r i ng) t ar get _username,( st r i ng) or i g_vi sname,( st r i ng) message

})

At the target mud, the message will be delivered to target_username with the appropriate formatting. The

message will contain $N tokens for substituting the originator's name. This name is typically formatted using:

spr i nt f ( "%s@%s" , or i g_vi sname, or i gi nator_mudname) .

The target_username should be lower-cased by the originating mud.

A simple example would be a message such as, "$N smiles at you." which would be transformed into

something like, "Joe@PutzMud smiles at you."

If the router or target mud fails to deliver the packet for some reason, it will return an errorpacket.

Service: who

The originator will deliver the following packet over the in-band network (to its router):

( {( st r i ng) " who- r eq",( i nt ) 5,( st r i ng) ori gi nator_ mudname,( st r i ng) or i gi nat or _user name,( st r i ng) t arget_mudname,(s t r i ng) 0

})

The router will route the packet to another router or to the target mud. The target mud returns:

( {( st r i ng) "who- r epl y",( i nt ) 5,( st r i ng) ori gi nator_mudname,( str i ng) 0,( st r i ng) t arget_mudname,( st r i ng) t ar get _user name,( mi xed *) who_dat a


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})

where who_data is an array containing an array of the following format for each user on the mud:

( {( st r i ng) user _vi sname,( i nt ) i dl e_t i me,(s t r i ng) xt r a_ i nf o

})

Each user_visname should specify the user's visual name. idle_time should be measured in seconds and

xtra_info should be a string.

If the router fails to deliver the packet for some reason, it will return an errorpacket.

Service: finger

Finger operates similarly to who but returns information about a specific user rather than all users logged into

the mud. This service uses the in-band network; the packet has the following format:

( {

( str i ng) " f i nger - req",( i nt ) 5,( st r i ng) ori gi nator_ mudname,( st r i ng) or i gi nat or _user name,( st r i ng) t arget_mudname,( str i ng) 0,( st r i ng) username

})

Note: technically, we could use the target_username field to hold the name of the person to finger, but we do

not wish to imply that the packet is destinedfor that user. The packet is only querying information about the

user.

The target mud will return:

( {( str i ng) " f i nger - repl y" ,( i nt ) 5,( st r i ng) ori gi nator_ mudname,( str i ng) 0,( st r i ng) t arget_mudname,( st r i ng) t ar get _username,( st r i ng) vi sname,( s t r i ng) t i t l e,( st r i ng) r eal _name,

( str i ng) e_mai l ,( st r i ng) l ogi nout _t i me,( i nt ) i dl e_t i me,( st r i ng) i p_name,(s t r i ng) l evel ,( str i ng) ext ra / / eg, a . pl an f i l e, or any ot her r el evant i nf o

})

A mud may return 0 for any item if they wish to keep the information private. In particular, it is suggested

that information about players (as opposed to wizards) be kept confidential.

The returnedvisname should contain the user's visual name. loginout_time specifies the (local) time the user


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logged in (if they are currently on) or the time the user logged out. The value should be expressed as a string.

It should be 0 to indicate no information. The idle_time is expressed as an integer number of seconds of idle

time. If this value is -1, then the user is not logged onto the mud at the moment.

Ifextra is given, then it should be terminated with a carriage return.

Service: locate

This service locates a particular user on the Intermud system. The following packet is delivered over the

in-band network (to the mud's router), which then delivers it to all muds (target_mudname == 0):

( {( str i ng) " l ocat e- r eq",( i nt ) 5,( st r i ng) ori gi nator_ mudname,( st r i ng) or i gi nat or _user name,( str i ng) 0,( s tr i ng) 0,( st r i ng) username

})

Ifthe requested user is logged into the receiving mud, then the following reply is returned:

( {( str i ng) " l ocat e- repl y" ,( i nt ) 5,( st r i ng) ori gi nator_ mudname,( str i ng) 0,( st r i ng) t arget_mudname,( st r i ng) t ar get _username,( st r i ng) l ocat ed_mudname,( st r i ng) l ocat ed_vi sname,( i nt ) i dl e_t i me,( str i ng) st at us,

})

located_visname should contain the correct visual name of the user. idle_time will have the idle time (in

seconds) of the located user.

status specifies any special status of the user. This will typically be zero to indicate that the user has no

special status. The values for this string are arbitrary, but certain statuses have predefined values that can be

used:

"link-dead"

"editing"

"inactive"

"invisible"

"hidden"

These predefined values are intended to cover those statuses that might modify a user's reception of Intermud

transmissions; they are not intended to be all-inclusive (and the string is arbitrary in any case). The

predefined way to specify multiple attributes is with a comma-space-separated list such as: "editing, hidden".

The located mud should not attempt to apply special formatting or other characters, instead leaving that to the

receiving mud.


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Other examples for the status string might be "afk for dinner" or "taking a test".

Service: channel

There are two types of channels in the Intermud system: selective admission and selective banning. All

channels are owned by a particular mud and are adminstrated by that mud only. The owner of a channel may

also choose to filter the channel, although this may subject that mud to an increased load for processing the

channel contents and the channel will become unavailable when the host mud is down.

The routers maintain three channel lists - one list for each type of channel (selective admission vs banning)

where the channel is unfiltered, and one list for selective admission, filtered channels. Selectively banned,

filtered channels are not allowed. For each channel, the router will store which type it is (what list it is on),

the owning mud of the channel, and a list of muds that are admitted/banned.

When a mud sends a startup-req-2 packet, it includes its chanlist-id in the packet. The router will potentially

respond with a chanlist-reply message to update the mud's channel list.

The router will respond to channel list changes with the chanlist-reply packet.

( {( str i ng) "chanl i s t - repl y" ,( i nt ) 5,( st r i ng) or i gi nat or _mudname, / / t he r out er( str i ng) 0,( st r i ng) t arget_mudname,( str i ng) 0,( i nt ) chanl i s t_ i d,( mappi ng) channel _l i st

})

channel_listis mapping with channel names as keys, and an array of two elements as the values. If the value

is 0, then the channel has been deleted. The array contains the host mud, and the type of the channel:

0 sel ect i vel y banned1 sel ect i vel y admi t t ed2 f i l t er ed ( sel ecti vel y admi t t ed)

All channel messages are delivered to the router. It will then pass the message to the appropriate set of muds.

If the channel is filtered, then the packet will be delivered to the host mud for filtering; it will then return to

the router network for distribution. It is assumed that a channel packet for a filtered channel that comes from

the channel host has been filtered.

Channel messages come in three flavors: standard messages, emotes, and targetted emotes. These use packets

channel-m, channel-e, and channel-t, respectively. They are:

( {( st r i ng) "channel - m",( i nt ) 5,( st r i ng) ori gi nator_ mudname,( st r i ng) or i gi nat or _user name,( str i ng) 0,( s tr i ng) 0,( st r i ng) channel _name,( st r i ng) vi sname,( st r i ng) message


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})

( {( st r i ng) "channel - e",( i nt ) 5,( st r i ng) ori gi nator_ mudname,( st r i ng) or i gi nat or _user name,( str i ng) 0,( s tr i ng) 0,( st r i ng) channel _name,

( st r i ng) vi sname,( st r i ng) message

})

( {( str i ng) "channel - t ",( i nt ) 5,( st r i ng) ori gi nator_ mudname,( st r i ng) or i gi nat or _user name,( str i ng) 0,( s tr i ng) 0,( st r i ng) channel _name,( st r i ng) t arget t ed_mudname,

( st r i ng) t ar get t ed_user name,( st r i ng) message_ot hers,( st r i ng) message_t ar get ,( st r i ng) ori gi nat or _vi sname,( st r i ng) t ar get _vi sname

})

When a mud receives a channel-m packet, it should deliver it locally to all listeners. The actual message

delivered to users should be a composition of the originator_mudname, visname, channel_name, and

message. The message should not be preformatted with this information before delivery so that individual

muds can define the display semantics. A suggested format is:

[ gwi z] J ohn@Doe Mud: hel p me! hel p me! I am a cl uebi e newl ess!

This was composed with:

spr i nt f ( " [ %s] %s@%s: %s" , channel _name, vi sname, or i gi nat or_mudname, message) ;

channel-e packets are similar to channel-m packets, but the message has a token in it to represent where the

originator's name should be. This token is $N. An example is "$N smiles."

### need more info here ###

When a mud receives a channel-t packet, it should deliver the message locally to all listeners. The actual

message delivered should be a composition of the channel_name and one of message_others ormessage_target. The messages will include $N and $O for the name of the originator and the object/target of

their emote. The appropriate message is selected based on the listener - if the listener matches the targetted

mud/user, then the message_target should be used. A suggested format is:

[ gwi z] Wi t h a f l yi ng l eap, J ohn@Doe Mud f al l s i nt o t he pi t .[ gwi z] J ane@Bl andMud waves t o Goober @Put zMud.[ gwi z] J ane@Bl andMud waves t o you.

These were composed with:

spr i nt f ( " [ %s] %s" , channel _name, one_of _t he_messages) ;


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### need a bit more on channel-t ###

All messages shouldnotbe terminated with a newline - that will be applied on the receiving mud if

necessary. The target_username should be in lower-case if provided.

A channel may be added with the following packet:

( {

( st r i ng) "channel - add",( i nt ) 5,( st r i ng) ori gi nator_ mudname,( st r i ng) or i gi nat or _user name,( st r i ng) t ar get _mudname, / / t he r out er( str i ng) 0,( st r i ng) channel _name,( i nt ) channel _t ype

})

The forchannel_type field accepts the same values that the name server returns for channels. Sending this

packet again with a new value for channel_type will change the information.

A channel may be removed by the mud that created it by sending the following packet:

( {( st r i ng) "channel - r emove",( i nt ) 5,( st r i ng) ori gi nator_ mudname,( st r i ng) or i gi nat or _user name,( st r i ng) t ar get _mudname, / / t he r out er( str i ng) 0,( st r i ng) channel _name

})

To administer a channel, the channels host/owner mud may use the following packet:

( {( st r i ng) " channel - admi n" ,( i nt ) 5,( st r i ng) ori gi nator_mudname,( st r i ng) or i gi nat or _user name,( st r i ng) t ar get _mudname, / / t he r out er( str i ng) 0,( st r i ng) channel _name,( str i ng *) add_to_ l i s t ,( st r i ng *) r emove_f r om_l i st

})

The muds specified in add_to_listare added to the allowed/banned list stored within the router network. Themuds specified in remove_from_listare removed from that list.

To filter a channel, the following packets will be used :

( {( str i ng) "chan- f i l t er - req",( i nt ) 5,( st r i ng) or i gi nator _mudname, / / t he r out er( str i ng) 0,( st r i ng) t arget_mudname, / / t he owner / host mud( str i ng) 0,


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( st r i ng) channel _name,( mi xed *) packet _t o_f i l t er,

})

Wherepacket_to_filteris a channel-m, channel-e or channel-t packet.

The filtered packet is returned to the router in the following packet :

( {

( str i ng) "chan- f i l t er - repl y" ,( i nt ) 5,( st r i ng) or i gi nat or_mudname, / / The channel host / owner mudname( str i ng) 0,( st r i ng) t ar get _mudname, / / t he r out er( str i ng) 0,( st r i ng) channel _name,( mi xed *) f i l t er ed_packet ,

})

A list of who is listening to a channel on a remote mud may be requested with the following packet:

( {

( st r i ng) "chan- who- r eq",( i nt ) 5,( st r i ng) ori gi nator_ mudname,( st r i ng) or i gi nat or _user name,( st r i ng) t arget_mudname,( str i ng) 0,( st r i ng) channel _name

})

The reply for the who request takes the following format:

( {( st r i ng) "chan- who- r epl y",

( i nt ) 5,( st r i ng) ori gi nator_mudname,( str i ng) 0,( st r i ng) t arget_mudname,( st r i ng) t ar get _user name,( st r i ng) channel _name,( str i ng *) user_ l i s t

})

The user_list should be an array of strings, representing the users' "visual" names.

A mud may decide whether or not it is listening to any given channel by sending a channel-listen packet. This

packet is also used to tune out a channel, which should be done whenever no one on the mud is listening tothe channel. The format of this packet is:

( {( str i ng) " channel - l i sten",( i nt ) 5,( st r i ng) ori gi nator_ mudname,( str i ng) 0,( st r i ng) t ar get _mudname, / / t he r out er( str i ng) 0,( st r i ng) channel _name,( i nt ) on_or_off

})


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The on_or_offwill contain one of the following values:

0 The mud does not wi sh t o recei ve t hi s channel .1 The mud wi shes t o recei ve t hi s channel .

Lastly, for targetted emotes, it is necessary to get information on the target. There are two pieces of

information required: the visname and the gender of the target. This operation is performed with the

following packets:

( {( st r i ng) "chan- user - r eq",( i nt ) 5,( st r i ng) ori gi nator_ mudname,( str i ng) 0,( st r i ng) t arget_mudname,( str i ng) 0,( st r i ng) username

})

Note that the username is separate since the packet is not targettedto the user.

The reply for the user info request takes the following format:

( {( st r i ng) " chan- user - r epl y",( i nt ) 5,( st r i ng) ori gi nator_ mudname,( str i ng) 0,( st r i ng) t arget_mudname,( str i ng) 0,( st r i ng) username,( st r i ng) vi sname,( i nt ) gender

})

The gender takes one of the following values:

0 mal e1 f emal e2 neut er

Note that a mud may have more variants on gender, but most human languages only have three forms at

most. These are used to select the appropriate pronouns, possessives, and reflexive words.

Service: news

### work to do here... this is an OOB service, also employing the auth service ###

This packet is used to transmit a request for a post to a remote mud's news server (via the OOB network).

This connection should not disconnect from the server until it is done dealing with it for the forseeable future.

Instead, it should exchange messages in lockstep with the server.

( {( st r i ng) "news- r ead- r eq",( i nt ) 5,( st r i ng) ori gi nator_ mudname,( st r i ng) or i gi nat or _user name,


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( s tr i ng) 0,( s tr i ng) 0,( st r i ng) newsgroup_name,( i nt ) i d,

})

The server response for this request takes the following form:

( {

( i nt ) post i ng_t i me,( str i ng) t hread_i d,( str i ng) subj ect,( str i ng) poster,( st r i ng) cont ent s

})

To post a message, send the following packet:

( {( st r i ng) " news- post - r eq",( st r i ng) ori gi nator_ mudname,( i nt ) mud_l ogi n_por t ,( st r i ng) mewsgroup,( str i ng) t hread_i d,( str i ng) subj ect,( str i ng) poster,( st r i ng) cont ent s

})

Notice that this packed does not follow the standard packet form, because it is not transmitted over the in

band network. The server response should be an integer representing the id of the post, or an error packet.

To request a list of newsgroups, send the following packet:

( {

( str i ng) "news- grpl i st- req"})

The response from the server should be an array containing an array for each available group. This array

should contain the following data:

( {( st r i ng) gr oup_name,( i nt ) f i r s t _pos t _ i d,( i nt ) l as t_pos t_ i d

})

Service: mail

This packet is used to deliver a mail message to a remote mud. It will be delivered over the OOB network

(i.e., over a direct TCP connection to the target mud's out-of-band TCP port). It has the following form:

( {( str i ng) "mai l " ,( i nt ) i d,( str i ng) or i g_user,( mappi ng) t o_l i st ,( mappi ng) cc_l i st ,( s t r i ng * ) bcc_ l i s t ,


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( i nt ) send_t i me,( str i ng) subj ect,( st r i ng) cont ent s,

})

Where to_listandcc_listare mappings of the following format :

( [MUD- A : ( { user - 1, user - 2, }) ,

MUD- B : ( { user - 1, user - 2, }) ,] )

and bcc_list is an array of the users at the target mud only.

Mail is acknoleged by the use of a "mail-ack" packet.

( {( str i ng) "mai l - ack",( mappi ng) ack_l i st ,

})

Where ack_list is a mapping whose keys are the id's that have been acknowleged, and the values are arrays ofthe failures. NB: mail is an OOB service, and employs the auth service. Errors must be sent via the OOB

network

Service: file

### work to do here... this is an OOB service, also employing the auth service ###

### this service still in development ###

This service is used to transfer files between muds. Before files may be transferred, a session token must be

returned from the remote mud using the login protocols.

It will use the out-of-band TCP port and has the following form:

To list the files on a remote mud, send the following packet:

( {( s t r i ng) " f i l e- l i st - r eq" ,( st r i ng) ori gi nator_ mudname,( st r i ng) or i gi nat or _user name,(s t r i ng) di r ,

})

Where diris the directory to be listed. diris considered to be relative to a world read/write directory. Anyleading '/' is ignored. The response from the remote mud should be:

( {( s t r i ng) " f i l e- l i st - r epl y" ,( st r i ng) t ar get _user name,( mi xed *) di r_ l i s t ,

})

Where dir_listis an array containing an array of the following format for each file in the reply list:

( {( st r i ng) f name,


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( i nt ) f si ze,( i nt ) f t i me,

})

To send a file to a remote mud, send the following packet:

( {( s t r i ng) " f i l e- put " ,( i nt ) i d,( st r i ng) ori gi nator_ mudname,

( st r i ng) or i gi nat or _user name,( st r i ng) r emote_f name,( st r i ng) cont ent s,

})

Puts are acknoleged by the following packet :

( {(s t r i ng) " f i l e- put - ack" ,( i nt ) i d,( i nt ) success,

})

To retrive a file from a remote mud, send the following packet:

( {(s t r i ng) " f i l e- get - req" ,( i nt ) i d,( st r i ng) ori gi nator_ mudname,( st r i ng) or i gi nat or _user name,( st r i ng) r emote_f name,

})

The remote mud should respond with

( {

(s t r i ng) " f i l e- get - repl y" ,( i nt ) i d,( i nt ) success,( st r i ng) cont ent s,

})

Where success corresponds to the following.

- 3 : Request Fai l ed ( wr i t e permi ssi on)- 2 : Request Fai l ed ( r ead permi ssi on)- 1 : Request Fai l ed ( f pat h er r or )0 : Request Fai l ed ( unknown err or )1 : Request successf ul

The file should only be transfered from a world writeable directory on one mud to a world writable directory

on another.

remote_fname is relative to the same directory as file-list-* and any leading '/' is ignored.

The size of the file capable of being sent in this manner is limited by the size of the maximum string length

on both the sending and receiving muds.

An error response should be returned over the OOB network.


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Service: auth

The auth service is used for performing authentication of a mud. This authentication is used for OOB

communications since in-band communication is always authenticated at a mud-level.

The authentication is used to verify that an incoming OOB connection request is actually from the mud that

the request says it is from. Before the OOB connection is made, the originator sends the following packet

(over the in-band network) to the target mud:( {

( st r i ng) "aut h- mud- r eq",( i nt ) 5,( st r i ng) ori gi nator_ mudname,( str i ng) 0,( st r i ng) t arget_mudname,(s t r i ng) 0

})

The target mud generates a unique integer key, associates that with the originating mud with the key, and then

returns the key (over the in-band network) to the originator with:

( {( st r i ng) "aut h- mud- r epl y",( i nt ) 5,( st r i ng) ori gi nator_ mudname,( str i ng) 0,( st r i ng) t arget_mudname,( str i ng) 0,( i nt ) sessi on_key

})

At this point, the originator may contact the target mud through the OOB port, using the session_key to

authenticate that it actually is the purported originator.

It is possible, and should be accounted for, that a particular originator might issue multiple auth-mud-req

packets before establishing an OOB session to the target mud. Only the lastrequest andsession_key need to

be remembered. The keys from prior requests may be discarded and connection attempts using them may be

rejected.

Session keys must remain valid for10 minutes from receipt of the auth-mud-req packet. After that point, the

target mud may discard the key and reject connection attempts with that key. After a successful OOB

connection is made, the target mud may discard the key (the key should be interpreted as a one-time key).

Service: ucache

The ucache service is used for maintaining user information caches within the Intermud network. A mud may

cache information that it receives from chan-user-reqpacket. To keep this up to date, muds should issue

ucache-update packets, which are then used by muds that implement the ucache service.

Whenever the contents of a chan-user-reply packet would change (visname orgender), then the mud should

broadcast the following packet:

( {( st r i ng) " ucache- updat e",


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( i nt ) 5,( st r i ng) ori gi nator_ mudname,( str i ng) 0,( s tr i ng) 0,( s tr i ng) 0,( st r i ng) username,( st r i ng) vi sname,( i nt ) gender

})

The contents of this packet are similar to the chan-user-reply packet.

Note that the router will filter this packet's delivery to only those muds that support the ucache service.

error

This packet is returned when error conditions arise. It has the following form:

( {( str i ng) "error" ,( i nt ) 5,( st r i ng) ori gi nator_mudname,( str i ng) 0,( st r i ng) t arget_mudname,( st r i ng) t ar get _user name,( st r i ng) er r or _code,( st r i ng) er r or _message,( mi xed *) err or_packet

})

The error_code values are standardized and are summarized in the Error Summary section. Theerror_message does not follow any particular standards (yet?), but should be a message that can be displayed

to a user. The error_packetmay contain the packet that caused the particular error to be generated. If the

packet is unavailable (i.e. due to code structure), then the value 0 may be used.

startup-req-3

This packet is delivered to a mud's router when the mud first establishes the connection. If the mud has never

received a password from a server, it should send 0. The server is responsible for creating a random password

for new muds, and validating the password of a mud before allowing a mud to connect from a site other than

the one from which it normally connects.

A startup-req-3 packet has the following form:

( {( str i ng) "st art up- req- 3",( i nt ) 5,( st r i ng) ori gi nator_mudname,( str i ng) 0,( st r i ng) t ar get _mudname, / / t he r out er( str i ng) 0,


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( i nt ) passwor d,( i nt ) ol d_mudl i st_i d,( i nt ) o l d_chanl i s t_ i d,

/ / t hese cor r espond t o t he val ues i n a mudl i st i nf o_mappi ng( i nt ) pl ayer_port ,( i nt ) i mud_t cp_por t ,( i nt ) i mud_udp_por t ,( st r i ng) mudl i b,( st r i ng) base_mudl i b,

( s tr i ng) dr i ver ,( st r i ng) mud_t ype,( st r i ng) open_st at us,( st r i ng) admi n_emai l ,( mappi ng) servi ces( mappi ng) ot her_data

})

The -3 on the packet type indicates that the mud will use Protocol Version 3 for communication (this

specification). Future changes in the protocol can update this number as required. The router network must

support all protocol versions and must translate packets between muds with different protocol versions. Error

packets will be returned to a mud if that mud attempts to use a service that cannot be translated (e.g. services

that are only available in later protocol versions).

Note: version 2 of the protocol had a smallerlocate-reply packet. No other changes were made to the

specification.

Note: version 1 of the protocol was almost exactly the same as this version except that it was missing a

couple fields from the startup packet and the corresponding info_mapping in the mudlist packet.

All pieces of information are required to be sent to a router except for the port numbers and other_data. The

player_port may be 0 if the mud is private/closed. The OOB ports may be 0 if the services that require them

will not be provided by the mud. other_data may be 0 if a mud has no "other data" (see below).

open_status is a string describing the current status of the mud. Suggested (strongly encouraged values) are:

"mudlib development"

"beta testing"

"open for public"

"restricted access"

mud_type specifies the type/family/genre of the mud driver. Examples are:LP,MOO

services is a mapping with service names as keys. The allowable services include those specified within this

specification (in the Services section); these simply have a value of 1 in the mapping. In addition, extended

(non-standard) services may be specified with service-specific information for their value. Here is the current

list of services (keys and values) that a mud may make available along with some example extended services:

"tell" : 1

"emoteto" : 1

"who" : 1

"finger" : 1

"locate" : 1


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"channel" : 1

"news" : 1

"mail" : 1

"file" : 1

"auth" : 1

"ucache" : 1

"smtp" : port-number

Specifies the port number of a mud's SMTP mail interface. Note that Intermud mail is normallydelivered via the OOB TCP port.

"ftp" : port-number

Specifies the port number of a mud's FTP service. Note that Intermud file transfer is normally delivered

via the OOB TCP port.

"nntp" : port-number

Specifies the port number of a mud's NNTP server. Note that Intermud news transfer is normally

delivered via the OOB TCP port.

"http" : port-numberSpecifies the port number of a mud's WWW server (httpd).

"rcp" : port-number

Specifies the port number of a mud's Remote Creator server (currently a facility provided by

Nightmare Lib IV).

"amcp" : version-string

Indicates the mud supports AMCP of some particular version.

Additional services and service-specific data may be added in the future as required.

The other_data field (when provided) contains a mapping with string keys. The values are arbitrary and

determined by the key. These key/value pairs are used to specify information that is not related directly to the

I3 network operation. At this time, there are no defined keys in this specification or via precedent. Individual

muds are free to define their own key/value pairs. It is highly recommended that attempts be made to avoid

namespace collisions. For example, if the Lima Mudlib decides to place an entry into the other_data field, it

might use a key of "lima-somekey".

startup-reply

This packet will be delivered to a mud for three conditions: in response to a startup-req packet, when therouter wishes the mud to connect to a different router, or when the set of routers change for some reason.

( {( str i ng) "start up- repl y",( i nt ) 5,( st r i ng) or i gi nator _mudname, / / t he r out er( str i ng) 0,( st r i ng) t arget_mudname,( str i ng) 0,(s t r i ng * ) r outer_ l i s t ,( i nt ) passwor d

})


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The router_listis an array representing an ordered list of routers to use. The first element should be the router

that the mud should use. Typically, this will be the router that the mud initially connected to. If not, however,

then the mud should close the connection and reopen to the designated router. The list should be saved and

used in case of failure to connect to a router. Each element in the list is an array of two elements; the first

element is the router name, the second element is the router's address in the following format: "ip.ad.re.ss

portnum". Note that this address can be passed to MudOS's socket_connect() function. For example: ( {

"*ni ghtmare", "199. 199. 122. 10 9000" }) .

The first router specified in the list will be the mud's preferred router. Future initial connections and

startup-req packets will go to that router until told otherwise.

shutdown

This packet is delivered to a mud's router when the mud is gracefully shutting down. It has the following

form:

( {( st r i ng) "shut down",( i nt ) 5,

( st r i ng) ori gi nator_ mudname,( str i ng) 0,( st r i ng) t ar get _mudname, / / t he r out er( str i ng) 0,( i nt ) restart _del ay

})

restart_delay can be used to specify when the mud thinks it will be restarted. This value is measured in

seconds. 0 may be used to mean unknown/indefinite. If a mud will be back "immediately," then it can simply

use 1 second for this.

If the restart_delay is greater than 5 minutes, then the router will mark the mud as "down" immediately rather

waiting the 5 minutes. Likewise, if the restart_delay specifies a duration longer than 7 days, the mud will bedeleted from the Intermud. Any time less than 5 minutes will cause the router to operate as normal: it will

wait for a while.

mudlist

The router will send this to a mud whenever the mud's list needs to be updated. Typically, this will happen

once right after login (based on the old_mudlist_id that a mud provided in the startup-req-3 packet), and then

as changes occur within the intermud network. A mud should remember the mudlist and its associated

mudlist_id across reconnects to the router.

( {( str i ng) "mudl i st" ,( i nt ) 5,( st r i ng) or i gi nat or _mudname, / / t he r out er( str i ng) 0,( st r i ng) t arget_mudname,( str i ng) 0,( i nt ) mudl i s t_ i d( mappi ng) i nf o_mappi ng

})

The info_mapping contains mud names as keys and information about each mud as the value. This


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information is specified as an array with the following format:

( {( i nt ) s tate,( str i ng) i p_addr,( i nt ) pl ayer_port ,( i nt ) i mud_t cp_por t ,( i nt ) i mud_udp_por t ,( st r i ng) mudl i b,( st r i ng) base_mudl i b,( s tr i ng) dr i ver ,( st r i ng) mud_t ype,( st r i ng) open_st at us,( st r i ng) admi n_emai l ,( mappi ng) servi ces( mappi ng) ot her_data

})

Each record of information should replace any prior record for a particular mud. If the mapping's value is

zero, then the mud has been deleted (it went down and has not come back for a week) from the Intermud.

state is an integer with the following values:

- 1 mud i s up0 mud i s downn mud wi l l be down f or n seconds

oob-req

### not sure on this packet... discussion required ###

This packet is delivered to a target mud when an originating mud wishes to connect to its OOB port. This

packet should only be delivered if the target mud does not support the auth service or if the service using the

OOB connection will not require use of the auth service.

The packet has the following form:

( {( st r i ng) " oob- r eq",( i nt ) 5,( st r i ng) ori gi nator_ mudname,( str i ng) 0,( st r i ng) t arget_mudname,( str i ng) 0,

})

The originating mud must then connect within 10 minutes. The target mud may use this opportunity to actualopen the OOB port and listen for the incoming connection request.

oob-begin

This packet is used over an OOB link (see OOB Protocols). It is used to specify the authorization information

for this connection.

Since this packet operates over an OOB link, it does not need to conform to standard packet formats. Its

format is:


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( {( st r i ng) "oob- begi n",( st r i ng) ori gi nator_ mudname,( i nt ) aut h_t ype,( i nt ) aut h_t oken

})

The auth_type will contain one of the following values:

0 no aut hent i cat i on used

1 aut h- mud- r eq used

oob-end

This packet is used over an OOB link (see OOB Protocols). It is used to signify that a mud is done delivering

packets to the other mud.

Since this packet operates over an OOB link, it does not need to conform to standard packet formats. Its

format is:

( {

( st r i ng) " oob- end",( st r i ng) mudname

})

mudname states who has completing delivering packets. This is used to simplify the process of determining

which mud (of a possible many outstanding OOB connections) just completed their work. This could be done

simply by matching the socket which received the data to a record of what mud it connected to, but

specifying the mud should make this process simpler for some clients.

### more to come ###

Originator uses target's auth service to fetch necessary authorization tokens. If authorization is not

needed, then an oob-reqpacket is sent. This step operates of the in-band network.

1.

Originator connects to target's OOB port.2.

Originator delivers an oob-begin packet, containing the authorization tokens, over the OOB link to the

target mud.

3.

The target mud validates the authorization tokens. If the validation fails, then the target mud closes the

connection.

4.

Target returns an oob-begin packet (with empty authorization information) to tell the originator tobegin.

5.

Originator delivers all queued packets to the target mud. The target should respond with various replies

and acknowledgements during this process. The target is not yet allowed to actively send packets yet.

6.

Originator delivers an oob-endpacket, signalling completion.7.

If the target mud has any packets to deliver in an outbound queue for the originator, then it performs

the deliveries. The originator should respond with various replies and acknowledgements during this

process.

8.

The target mud delivers an oob-endpacket if no deliveries are to be made, or upon completion of the

deliveries.

9.


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If the originator has futher packets to deliver (some may have been placed in the originator's outbound

queue during this process), then the process returns to step #6.

10.

The originator drops the connection.11.

The target mud may time out and close the connection if it does not receive any packets for 10 minutes.

The routers will create, open, and maintain MUD mode TCP sessions with each of the other routers. Each

router will also maintain a list of the status of all links in the router network. This link information will be

used for routing around a failed link until the link is reestablished.

Each router will maintain a complete list of all muds on the Intermud, the information associated with each

one, the up/down/rebooting state, and which router the mud is connected to.

Each router will also maintain a list of information about each Intermud channel, including the channel

host/owner, the type of channel, and the list of admitted/banned muds for the channel.

List Synchronization

The two sets of lists are synchronized with the same scheme from a mud's point of view: they receive a

unique token that precisely denotes the state of their list. The router network can remember how to provide

deltas from one token to another or can just deliever complete lists when a request arrives from a mud that

needs an update.

To guarantee uniqueness of the token, the routers can use the current time. This becomes complex because all

routers must use the same token for the list (in case a mud is switched to a new router, it should not have to

fetch the whole list). Using the time across multiple machines with different time drifts and within differenttime zones and accounting for poor system administration can make the problem quite difficult. A scheme is

required to meet each of these problems.

Assume a steady state where each router has the same token and a consistent list with respect to the other

routers. Now, let us say a router generates a delta to the list. It will create a new token as max(ol d_t oken +

1, t i me( ) ) . This token will be passed with the list delta to all other routers. The other routers will install the

change, record the new token, and propogate the information to their connected muds. Within the router

network, the router that originated the current token is remembered. This is needed to uniquely identify deltas

that occurred at the same instant. Using the above formula for creating the token also ensures that a router

will generate unique tokens even if they occur within the same second (the second token will be 1 more than

the first).

Now, what happens when two routers generate deltas at about the same time? Call the tokens t 1 andt 2 and

they are ordered as t 1 < t 2. There are two situations that will occur: a router will receive t1 before t2, or

vice-versa. First, the stable-state token must be specified for this situation (it cannot simply be the last token

to arrive; otherwise, some routers will have t1 and some will have t2). The rule is simply: f i nal _t oken =

max( t 1, t 2) .

Now, if a router receives t1 before t2, then everything will be fine - it will have notified its muds with the

t1-delta then with the t2-delta. The muds and the router will become stable with a current token of t2.


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However, if the router receives t2 first, then there will be problems. It will notify the muds with the t2-delta,

then with the t1-delta. The router will deliver a token of t2 with the t1-delta change to the muds and will

stabilize with that token. This would seem to be okay unless a mud disconnected between the t2-delta and

t1-delta notifications. When it reconnects, it will ask for changes since t2 and receive none. Simply put: the

t1-delta is subverted to using the t2 token and therefore does not uniquely identify the change.

This problem is solved with the use of a "alter-token" packet. The t1-delta gets a new token applied to it and

is recirculated through the router network. Since many routers may see the conflict and initiate an alter-token

operation, there should be a way to eliminate duplicates; otherwise, two altered-t1-deltas could again create a

synchronization problem. To overcome this, the altered token will be set to t2+1. The routers will ignore the

receipt of an altered-token-delta if its current token came from a similar altered-token.

### todo: two packets with same time; multiple packets? - solve case of two - inductance handles rest ###

( {( str i ng) "XXXl i s t - del t a" ,( i nt ) 5,( st r i ng) or i gi nat or _mudname, / / t he r out er( str i ng) 0,( str i ng) "*", / / r out er br oadcast( str i ng) 0,( i nt ) t oken,( mappi ng) l i st _del t a_i nf o

})

( {( str i ng) "XXXl i st- al t ered",( i nt ) 5,( st r i ng) or i gi nat or _mudname, / / t he r out er( str i ng) 0,( str i ng) "*", / / r out er br oadcast( str i ng) 0,( i nt ) al t er ed_t oken,

( mappi ng) l i st _del t a_i nf o})

Packet Routing

To efficiently implement the routing, the routers will route based entirely on the originator/target fields of the

packet. Knowledge of the packet types will not be required. This provides flexibility for extensions and, most

likely, increased routing speed.

Rules for routing are based entirely on the target_mudname. If it is provided, then the packet will be sent to

the mud if it is connected to the receiving router. Otherwise, the router for the mud is looked up and the

packet is forwarded there. If the mudname refers to the router itself, then the packet will be passed "up" to

higher-level router processes.

### info on routing around downed links ###

There will exist two reference implementations of the mudlib side of the protocol. These can be ported/used


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to create implementations for alternate mudlibs and for MudOS pre-v21 drivers.

For drivers that have TCP but not MUD-mode, they will need to parse the incoming transmissions

(MUD-mode is effectively a combination of save_variable() and a standard TCP socket).

For drivers without TCP sockets, then a gateway will need to be written to hook into the router network and

gateway the protocol between the MUD-mode TCP sockets and, say, UDP.

Gateways can also be used for non-LP based muds (e.g MOO, MUCK, Diku, etc).

Note that it is possible for the router network protocol to evolve independently of the protocol used by the

muds. This could involve moving away from the MUD-mode style of communication.

There are a "standard" set of error_codes that are returned by routers and remote muds in errorpackets. The

error_message is not as well defined at this point, but should be something that can be displayed to the user.

Following is a list of the standard error codes returned by the routers:

unk-dst : unknown destination mud

not-imp : feature not yet implemented

unk-type : unknown packet type (also sent by muds)

unk-src : unknown source of packet (unregistered mud)

bad-pkt : bad packet format (also sent by muds)

bad-proto : protocol violation (packet used incorrectly, at the wrong time, etc)

not-allowed : operation not allowed (e.g. channel bans)

Following is a list of standardized error codes that a mud may return:

unk-type : unknown packet type (also sent by router)

unk-user : unknown target user

unk-channel : unknown channel name

bad-pkt : bad packet format (also sent by router)

tell : send a message to a remote useremoteto : send an emote to a remote user

who-req: request a list of users on a remote mud

who-reply : reply with a list of users on a remote mud

finger-req: request finger information for a remote user

finger-reply : reply with finger information for a remote user

locate-req: request the location of a user

locate-reply : reply with the location of a user

chanlist-reply : reply with/update the list of available channels


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channel-m : send a message over a channel

channel-e : send an emote over a channel

channel-t : send a targetted emote over a channel

channel-add: register a new channel

channel-remove : remove a channel from name server databases.

channel-admin : adminstrate the participants of a channel

chan-filter-req: filter a channel

chan-filter-reply : return filtered channel messages to the routerchan-who-req: request a who list for people listening to a channel on a remote mud

chan-who-reply : return a requested channel who list

channel-listen : tune a mud as a whole into or out of a channel

chan-user-req: request channel user's info

chan-user-reply : reply with channel user's info

news-read-req: retrieve a news post from an OOB news server.

news-post-req: post news to an OOB news server.

news-grplist-req

mail : deliver an item of mail

mail-ack: acknoledge a mail

file-list-req: request a list of files on a remote mud

file-list-reply : reply with list list

file-put : send a file to a remote mud

file-put-ack: acknoledge a file-put

file-get-req: get a file from a remote mud

file-get-reply : reply with the requested file

auth-mud-req: request a mud-level authorization token

auth-mud-reply : reply with a mud-level authorization token

ucache-update : update cached user information

error: provide error information

startup-req-3 : provide start up information to the router

startup-reply : reply with/update the basic startup information (router list)

shutdown : gracefully indicate shutdown

mudlist : reply with/update the list of available muds

oob-req: request setup for OOB connection

oob-begin : begin OOB communication

oob-end: end one side of an OOB process

### to be filled in with specifics ###

Generally, many of the fields will be replaced with numbers rather than full strings. Some of the fields can be

paired up using various combined keys. For example, originator_mudname can almost always be ommitted

since it can be inferred from the TCP session at the router end. Also, all the request/reply pairs can use a

request key rather than recording actual user names (the user is associated with the request key on the

originating mud).


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Deathblade, February 15

added section for contributors and implementors

removed the section on reference implementations

cleared up a couple OOB items

Winddle, January 7

update file, removing local_fname and references to /ftp to remove some confusion.Deathblade, December 20

add this change log

update to startup-req-3 for the change in the locate-reply packet

Winddle, December 6

minor fix to mail

fix TTL to be int in chan-filter-reply

Winddle, October 20

update to mail

update to file

fixed a few 'broken' linksDeathblade, October 7

update to startup-req-2

modify the startup-req-2 packet and the mudinfo records to include "admin_email" and

"other_data"

add amcp service

strip really old changelog entries

Winddle, September 24

add typecasting

Deathblade, September 10

add some OOB from Winddleremove auth-user-xxx

Deathblade, August 9

added OOB information

Deathblade, August 8

add the auth, emoteto, ucache services

add section for OOB discussion

added a couple more standard errors

renamed some news packets to fit within the "news name space"

add comments to mail, file, and news protos re: auth service


Intermud-3_ a Proposal for the Future

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Transcript of Intermud-3_ a Proposal for the Future