Mavryk_p2p.P2p_socket
Typed and encrypted connections to peers.
This module defines:
It is parametric in two (abstract data) types. 'msg
is the unit of communication. 'meta
is a type of message sent in session establishment.
Connections defined in this module wrap a P2p_io_scheduler.connection
(which is simply a file descriptor on which R/W are regulated.)
Each connection has an associated internal read (resp. write) queue containing messages (of type 'msg
), whose size can be limited by providing corresponding arguments to accept
.
Type of a connection that successfully passed the authentication phase, but has not been accepted yet. Parametrized by the type of expected parameter in the `ack` message.
Type of an accepted connection, parametrized by the type of messages exchanged between peers.
equal t1 t2
returns true iff the identities of the underlying P2p_io_scheduler.connection
s are equal.
val pp : Stdlib.Format.formatter -> ('msg, 'meta) t -> unit
val info :
('msg, 'meta) t ->
'meta Mavryk_base.TzPervasives.P2p_connection.Info.t
val local_metadata : ('msg, 'meta) t -> 'meta
local_metadata t
returns the metadata provided when calling authenticate
.
val remote_metadata : ('msg, 'meta) t -> 'meta
remote_metadata t
returns the remote metadata, communicated by the remote host when the session was established.
val private_node : ('msg, 'meta) t -> bool
These should be used together to implement the session establishment protocol. Session establishment proceeds in three synchronous, symmetric, steps. The first two steps are implemented by authenticate
. The third step is implemented by either accept
or nack
.
1. Hosts send each other an authentication message. The message contains notably a public key, a nonce, and proof of work stamp computed from the public key. PoW work is checked, and a session key is established (authenticated key exchange). The session key will be used to encrypt/authenticate all subsequent messages over this connection.
2. Hosts send each other a 'meta
message.
3. Each host send either an Ack
message (accept
function) or an Nack
message (nack
function). If both hosts send an Ack
, the connection is established and they can start to read/write 'msg
.
Note that P2p_errors.Decipher_error
can be raised from all functions receiving messages after step 1, when a message can't be decrypted.
Typically, the calling module will make additional checks after step 2 to decide what to do in step 3. For instance, based on network version or 'meta
information.
val authenticate :
canceler:Lwt_canceler.t ->
proof_of_work_target:Mavryk_crypto.Crypto_box.pow_target ->
incoming:bool ->
P2p_io_scheduler.connection ->
Mavryk_base.TzPervasives.P2p_point.Id.t ->
?advertised_port:int ->
Mavryk_base.TzPervasives.P2p_identity.t ->
Mavryk_base.TzPervasives.Network_version.t ->
'meta Mavryk_base.TzPervasives.P2p_params.conn_meta_config ->
('meta Mavryk_base.TzPervasives.P2p_connection.Info.t
* 'meta authenticated_connection)
Mavryk_base.TzPervasives.tzresult
Lwt.t
authenticate canceler pow incoming conn point ?port identity version meta
returns a couple (info, auth_conn)
tries to set up a session with the host connected via conn
.
Can fail with
P2p_errors.Not_enough_proof_of_work
if PoW target isn't reachedP2p_errors.Myself
if both hosts are the same peerP2p_errors.Connection_closed
if the remote peer closes the connectionval nack :
'meta authenticated_connection ->
Mavryk_base.TzPervasives.P2p_rejection.t ->
Mavryk_base.TzPervasives.P2p_point.Id.t list ->
unit Lwt.t
nack ac motive alts
sends a Nack
message with the rejection motive
and a list of proposed alternative points to the remote peer, notifying it that its connection is rejected. It then closes the connection.
alts
must contain less than 100 points or you will be greylisted
val accept :
?incoming_message_queue_size:int ->
?outgoing_message_queue_size:int ->
?binary_chunks_size:int ->
canceler:Lwt_canceler.t ->
'meta authenticated_connection ->
'msg Mavryk_base.TzPervasives.Data_encoding.t ->
('msg, 'meta) t Mavryk_base.TzPervasives.tzresult Lwt.t
Accepts
sends an Ack message
to the remote peer and wait for an Ack
from the remote peer to complete session set up. This can fail with errors:
P2p_errors.Rejected_socket_connection
on connection closedP2p_errors.Rejected_by_nack
if Nack
is receivedP2p_errors.Invalid_auth
thrown if P2p_error.Decipher_error
val check_binary_chunks_size : int -> unit Mavryk_base.TzPervasives.tzresult
Check for the ?binary_chunks_size
parameter of accept
.
val write :
('msg, 'meta) t ->
'msg ->
unit Mavryk_base.TzPervasives.tzresult Lwt.t
write conn msg
returns when msg
has successfully been added to conn
's internal write queue or fails with a corresponding error.
val write_now :
('msg, 'meta) t ->
'msg ->
bool Mavryk_base.TzPervasives.tzresult
write_now conn msg
is Ok true
if msg
has been added to conn
's internal write queue, Ok false
if msg
has been dropped, or fails with a corresponding error otherwise.
type of an encoded_message parameterized by the type of message it can be encoded from
val copy_encoded_message : 'msg encoded_message -> 'msg encoded_message
Copies and encoded message in a newly allocated one
val encode :
('msg, 'meta) t ->
'msg ->
'msg encoded_message Mavryk_base.TzPervasives.tzresult
Encodes a message to be used with write_encoded_now
.
val write_encoded_now :
('msg, 'meta) t ->
'msg encoded_message ->
bool Mavryk_base.TzPervasives.tzresult
Similar to write_now conn msg
but with a preencoded message. msg
will be overwritten and should not be used after this invocation. It will fail if called on a closed connection with the `P2p_errors.Connection_closed` error.
val write_sync :
('msg, 'meta) t ->
'msg ->
unit Mavryk_base.TzPervasives.tzresult Lwt.t
write_sync conn msg
returns when msg
has been successfully sent to the remote end of conn
, or fails accordingly.
val read :
('msg, 'meta) t ->
(int * 'msg) Mavryk_base.TzPervasives.tzresult Lwt.t
read conn msg
returns when msg
has successfully been popped from conn
's internal read queue or fails with a corresponding error.
val read_now :
('msg, 'meta) t ->
(int * 'msg) Mavryk_base.TzPervasives.tzresult option
read_now conn msg
is Some msg
if conn
's internal read queue is not empty, None
if it is empty, or fails with a corresponding error otherwise.
val stat : ('msg, 'meta) t -> Mavryk_base.TzPervasives.P2p_stat.t
stat conn
is a snapshot of current bandwidth usage for conn
.
val add_closing_reason :
reason:P2p_disconnection_reason.t ->
('msg, 'meta) t ->
unit
Stores a reason for which it will be closed in a near future.
val close :
?wait:bool ->
reason:P2p_disconnection_reason.t ->
('msg, 'meta) t ->
unit Lwt.t