lokinet/doc/dht_v0.txt

DHT messages

these messages can be either wrapped in a LIDM message or sent anonymously over a path

This document is currently out of date (probably)


find introduction message (FIM)

recursively find an IS by SA

{
  A: "F",
  R: r_counter,
  S: "<32 bytes SA>",
  T: transaction_id_uint64,
  V: 0
}

Transactions will persist until replied to by a GIM or 60 seconds, whichever
is reached first.

If the timeout is reached before a GIM or the forwarding of the request fails:

* close transaction
* close linked transactions

if R is non-zero and less or equal to than 5:

* decrement R by 1
* open a transaction with id T for sender's RC.k
* pick random dht capable router, F
* generate new transaction id, U
* open a transaction with id U for F.k
* link transaction U to transaction T
* send FIM with transaction id U to F

if R is greater than 5 or less than 0:

* increment shitlist value of sender's RC.k by 1
* if the shitlist value for sender's RC.k is less than 10 reply with a GIM with
  an X
* if the shitlist value for sender's RC.k is equal to or greater than 10 drop
  the message

if R is zero and we have 1 or more IS at position S in dht keyspace:

* reply with a GIM holding the IS who contains the introducer with the highest
  expiration timestamp
 
if R is zero and we do not have any IS at position S in dht keyspace:

* find a router who's RC.k is closest to S, N

if N is our router:

* reply with a GIM with an empty X value

if N is not our router:

* open transaction with id T for sender's RC.k
* generate new transaction id, U
* open transaction with id U for N.k
* link transaction U to transaction T
* forward request to N using transaction id U


got introduction message (GIM)

{
  A: "G",
  I: [IS],
  T: transaction_id_uint64,
  V: 0,
}

if we have a transaction with id T:

* forward the GIM to all linked transactions
* terminate transaction T

when a linked transaction gets a GIM:

* set T to the current transaction id
* foward the GIM to the requester of T


publish introduction message (PIM)

publish one IS to the DHT.

version 0 uses the SA of the IS as the keyspace location.

in the future the location will be determined by the dht kdf
which uses a shared random source to obfuscate keyspace location.


R is currently set to 0 by the sender.

{
  A: "I",
  I: IS,
  R: r_counter,
  S: optional member 0 for immediate store otherwise non zero,
  V: 0
}

if R is greater than 0, do a random walk, otherwise if we are
closer to the SA of the IS than anyone else we know in the DHT 
store the IS for later lookup. 

If S is provided store the IS for later lookup unconditionally, 
decrement S by 1 and forward to dht peer who is next closest to 
the SA of the IS. If S is greater than 3, don't store and discard
this message.


find router contact message (FRCM)

find a router by long term RC.k public key

{
  A: "R",
  K: "<32 byte public key of router>",
  T: transaction_id_uint64,
  V: 0
}

find RC who's RC.k is closest to K:

if A.k is equal to K:

* reply with a GRCM with an R value of just A

if A.k is not equal to K and we are closesr to A.k than anyone we know:

* reply with a GRCM with an empty R value

find a pending transaction id for K, P

if P exists:

* link transaction T to P

if P does not exist:

* generate a new transaction id, U
* start transaction U for A.k
* link transaction U to transaction T
* send FRCM to A.k requesting K

got router contact message (GRCM)

R is a list containing a single RC if found or is an empty list if not found
sent in reply to FRCM only

{
  A: "S",
  R: [RC],
  T: transaction_id_uint64,
  V: 0
}

* send a GRCM with R to requesters in all linked transactions
* terminate transaction with id T