Module Conduit

Interface for establishing reliable stream-oriented connections.

This library abstracts the concerns of establishing connections to peers that may be running within the same host (e.g. in another virtual machine) or on a remote host via TCP. It consists of one library that is responsible for establishing individual connections, and a name resolver that maps URIs to endpoints.

Connection Establishment

Connections are created by identifying remote nodes using an endp value. To ensure portability, the endp values are translated into concrete connections by separate modules that target Lwt_unix, Async and Mirage. This lets those backends use the appropriate local technique for creating the connection (such as using OpenSSL on Unix, or a pure OCaml TLS+TCP implementation on Mirage, or some other combination).

The modules dealing with connection establishment are:

Name Resolution

This deals with resolving URIs into a list of endp addresses that can then be connected to by the connection establishment modules.

All of the name resolvers conform to the RESOLVER module type. The OS-specific implementations of this interface are:

type endp = [
| `TCP of Ipaddr.t * int

IP address and destination port

| `Unix_domain_socket of string

Unix domain file path

| `Vchan_direct of int * string

domain id, port

| `Vchan_domain_socket of string * string

Vchan Xen domain socket

| `TLS of string * endp

Wrap in a TLS channel, hostname,endp

| `Unknown of string

Failed resolution


End points that can potentially be connected to. These are typically returned by a call to a resolver.

val sexp_of_endp : endp -> Ppx_sexp_conv_lib.Sexp.t
val endp_of_sexp : Ppx_sexp_conv_lib.Sexp.t -> endp
val __endp_of_sexp__ : Ppx_sexp_conv_lib.Sexp.t -> endp
module type IO = sig ... end

Module type for cooperative threading that can be satisfied by Lwt or Async