lokinet/doc/dht_v0.txt

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2018-05-30 20:53:55 +00:00
DHT messages
these messages can be either wrapped in a LIDM message or sent anonymously over a path
find introduction message (FIM)
recursively find an IS.
variant 1, by SA
{
A: "F",
R: r_counter,
S: "<32 bytes SA>",
T: transaction_id_uint64,
V: 0
}
variant 2, by claimed name
{
A: "F",
N: "service.name.tld",
R: r_counter,
T: transaction_id_uin64,
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",
T: transaction_id_uint64,
V: 0,
X: [ IS, IS, IS, ... ]
}
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 or many IM into the dht at once.
each IS will be placed in the dht
version 0 uses the SA of each 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 3 +/- 2 by the sender.
{
A: "P",
R: r_counter,
V: 0,
X: [ IS, IS, IS, ... ]
}
The following steps happen in order:
first stage: reduction
if X's length is divisble by 2:
* split X in half as J and K
* generate 2 new PIM with the same values as the parent with empty X
* put J and K into the new PIM's X values
* associate the 2 new PIM with the current PIM batch
if X's length is not divisible by 2 and greater than 1:
* pop off an IS from X as A
* generate a new PIM with the same values as the parent with an X value of A
* associate the new PIM with the current PIM batch
* associate the old PIM having A removed from X with the current PIM batch
if X's length is 1:
* associate the PIM with the current PIM batch
any other cases for X are ignored.
for each PIM in the current batch:
if R is greater than 0:
* decrement R by 1
* queue the PIM for shuffle (second stage)
if R is 0:
* queue the PIM for distribution (third stage)
if R is less than 0:
* drop the message entirely
second stage: shuffle
* The dht node waits until we have collected 10 or more PIM or for 5 seconds,
which ever comes first.
* shuffle the list of IS randomly
* re-combine the IS into new PIMs
* queue each newly shuffled PIM for distribution (third stage)
if we collected 10 or more PIM:
* X holds 5 IS at most
if we collected less than 10 but more than 1 PIM:
* X holds 2 IS at most
if we only collected 1 PIM:
* the single PIM is unmodified
third stage: distribution
if R is less than 0:
* drop message and terminate current transaction, this should never happen but
this case is left here in the event of implementation bugs.
if R is greater than 0:
* pick a random dht capable router, N
* forward the PIM to N
if R is equal to 0:
for each IS in X as A:
* find the router closest to the SA in A, N
if N is our router:
* create dht positon S from SA in A
* store A for lookup at S
if N is not our router:
* send a PIM with X value containing just A to N
In the future post random walk keyspace batching may be done here.
As of version 0, none is done.
find router contact message (FRCM)
find a router by long term RC.k public key
{
A: "F",
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: "G",
R: [RC],
T: transaction_id_uint64,
V: 0
}
* send a GRCM with R to requesters in all linked transactions
* terminate transaction with id T
notes:
if we get a GRCM with empty R on one Tx and then one with a filled R on another
with the same K, the request is terminated by the first message as not found.
A backtrack case is needed.