Messages and enums

Every wire message has a strongly-typed DTO under RhpV2.Client.Protocol. They all derive from the abstract RhpMessage and surface their type discriminator through a read-only Type property.

DTO catalogue

Discriminator	DTO	Direction
auth	AuthMessage	C → S
authReply	AuthReplyMessage	S → C
open	OpenMessage	C → S
openReply	OpenReplyMessage	S → C
socket	SocketMessage	C → S
socketReply	SocketReplyMessage	S → C
bind	BindMessage	C → S
bindReply	BindReplyMessage	S → C
listen	ListenMessage	C → S
listenReply	ListenReplyMessage	S → C
connect	ConnectMessage	C → S
connectReply	ConnectReplyMessage	S → C
send	SendMessage	C → S
sendReply	SendReplyMessage	S → C
sendto	SendToMessage	C → S
sendtoReply	SendToReplyMessage	S → C
recv	RecvMessage	S → C
accept	AcceptMessage	S → C
status	StatusMessage	both
statusReply	StatusReplyMessage	S → C
close	CloseMessage	both
closeReply	CloseReplyMessage	S → C
(other)	UnknownMessage	S → C

Common base members

public abstract class RhpMessage
{
    public abstract string Type { get; }   // "auth", "openReply", ...
    public int? Id    { get; set; }        // request/reply correlation
    public int? Seqno { get; set; }        // server-pushed events
}

• Id is auto-assigned by RhpClient.RequestAsync if you leave it null.
• Seqno is set by the server on async notifications (RECV, ACCEPT, STATUS, server-initiated CLOSE) and is round-tripped on read.

Server extensions on replies

OpenReplyMessage.Crossed (bool?) carries pdn's "crossed": true extension: the open succeeded, and the node's call crossed the peer's own call to us. It is null whenever the server says nothing, which is always the case with XRouter, so treat null as "unknown" rather than "did not cross". A "crossed": false on the wire reads as null too, so only true ever means crossed. RhpClient.OpenAsync returns just the handle; call OpenWithReplyAsync (same parameters) to get the reply itself:

var reply = await rhp.OpenWithReplyAsync(
    ProtocolFamily.Ax25, SocketMode.Stream,
    port: "1", local: "G8PZT", remote: "GB7PZT",
    flags: OpenFlags.Active);

if (reply.Crossed == true)
{
    // The far end dialled us at the same moment; don't wait for its prompt.
}

See Server extensions in the protocol primer.

Constants and enums

The RhpV2.Client.Protocol namespace ships strongly-typed constants for every place the wire format uses a string token:

public static class ProtocolFamily { public const string Ax25 = "ax25"; ... }
public static class SocketMode     { public const string Stream = "stream"; ... }

[Flags]
public enum OpenFlags
{
    Passive          = 0x00,
    TraceIncoming    = 0x01,
    TraceOutgoing    = 0x02,
    TraceSupervisory = 0x04,
    Active           = 0x80,
}

[Flags]
public enum StatusFlags { None = 0, ConOk = 1, Connected = 2, Busy = 4 }

public static class RhpErrorCode { public const int Ok = 0; ... public static string Text(int); }
public static class RhpMessageType { public const string Auth = "auth"; ... }

Serializing & parsing manually

You shouldn't normally need this — RhpClient does it for you — but RhpJson is exposed for tools and tests:

byte[] bytes = RhpJson.Serialize(new OpenMessage {
    Pfam = ProtocolFamily.Ax25, Mode = SocketMode.Stream,
    Local = "G8PZT", Flags = (int)OpenFlags.Passive,
});

RhpMessage parsed = RhpJson.Deserialize(bytes);
if (parsed is OpenReplyMessage r) { ... }

The serializer always places type as the first key for readability and spec compliance. The deserializer dispatches on type to the right DTO and returns UnknownMessage for unknown values, preserving the raw JSON.