package mirage-protocols
Library
Module
Module type
Parameter
Class
Class type
Transmission Control Protocol layer: reliable ordered streaming communication.
The type for TCP errors.
The type for TCP write errors.
The type for input function continuation to pass onto the underlying IP layer. This will normally be a NOOP for a conventional kernel, but a direct implementation will parse the buffer.
include Mirage_device.S
include Mirage_flow.S
with type flow := flow
and type error := error
and type write_error := write_error
val pp_write_error : write_error Fmt.tpp_write_error is the pretty-printer for write errors.
read flow blocks until some data is available and returns a fresh buffer containing it.
The returned buffer will be of a size convenient to the flow implementation, but will always have at least 1 byte.
When read returns `Eof or an error, close (or shutdown) should be called on the flow by the client. Once read returned `Eof or an error, no subsequent read call will be successful.
val write : flow -> Cstruct.t -> (unit, write_error) result Lwt.twrite flow buffer writes a buffer to the flow. There is no indication when the buffer has actually been sent and, therefore, it must not be reused. The contents may be transmitted in separate packets, depending on the underlying transport. The result Ok () indicates success, Error `Closed indicates that the connection is now closed and therefore the data could not be written. Other errors are possible.
The promise is resolved when the buffer has been accepted by the implementation (if a partial write occured, write will wait until the remainder of the buffer has been accepted by the implementation).
If write returns an error, close (or shutdown) should be called on the flow by the client. Once write returned an error, no subsequent write or writev call will be successful.
val writev : flow -> Cstruct.t list -> (unit, write_error) result Lwt.twritev flow buffers writes a sequence of buffers to the flow. There is no indication when the buffers have actually been sent and, therefore, they must not be reused. The result Ok () indicates success, Error `Closed indicates that the connection is now closed and therefore the data could not be written. Other errors are possible.
The promise is resolved when the buffers have been accepted by the implementation (if a partial write occured, writev will wait until all buffers have been accepted by the implementation).
If writev returns an error, close (or shutdown) should be called on the flow by the client. Once writev returned an error, no subsequent writev or write call will be successful.
shutdown flow mode shuts down the flow for the specific mode: A flow which is shutdown `read (or `read_write) will never be read again (subsequent calls will return `Eof); a flow which is shutdown `write (or `read_write) flushes all pending writes and signals the remote endpoint there won't be any future write or writev calls (subsequent calls will return `Closed). E.g. in TCP, the signalling is done by sending a segment with the FIN flag.
If this flow is layered upon another flow' (e.g. TLS over TCP), and the internal state after shutdown is `Closed, close on the underlying flow' is executed.
close flow terminates the flow and frees all associated data. Any subsequent read or write will return an error. A subsequent close will not do anything (esp. not raising an exception), but it may log an error.
If this flow is layered upon another flow' (e.g. TLS over TCP), close on the underlying flow' is executed.
Get the destination IPv4 address and destination port that a flow is currently connected to.
val write_nodelay : flow -> Cstruct.t -> (unit, write_error) result Lwt.twrite_nodelay flow buffer writes the contents of buffer to the flow. The thread blocks until all data has been successfully transmitted to the remote endpoint. Buffering within the layer is minimized in this mode. Note that this API will change in a future revision to be a per-flow attribute instead of a separately exposed function.
val writev_nodelay : flow -> Cstruct.t list -> (unit, write_error) result Lwt.twritev_nodelay flow buffers writes the contents of buffers to the flow. The thread blocks until all data has been successfully transmitted to the remote endpoint. Buffering within the layer is minimized in this mode. Note that this API will change in a future revision to be a per-flow attribute instead of a separately exposed function.
create_connection ~keepalive t (addr,port) opens a TCPv4 connection to the specified endpoint.
If the optional argument ?keepalive is provided then TCP keep-alive messages will be sent to the server when the connection is idle. If no responses are received then eventually the connection will be disconnected: read will return Ok `Eof and write will return Error `Closed
type listener = {process : flow -> unit Lwt.t;(*process a connected flow
*)keepalive : Keepalive.t option;(*optional TCP keepalive configuration
*)
}A TCP listener on a particular port
input t listeners returns an input function continuation to be passed to the underlying IP layer.
When the layer receives a TCP SYN (i.e. a connection request) to a particular port, it will evaluate listeners port:
- If
listeners portisNone, the input function will return an RST to refuse the connection. - If
listeners portisSome listenerthen the connection will be accepted and the resulting flow will be processed bylistener.process. Iflistener.keepaliveisSome configurationthen the TCP keep-aliveconfigurationwill be applied before callinglistener.process.