First Commit

io/interface.go

@@ -0,0 +1,56 @@
+package io
+
+import (
+	"context"
+	"net"
+)
+
+type Verdict int
+
+const (
+	// VerdictAccept accepts the packet, but continues to process the stream.
+	VerdictAccept Verdict = iota
+	// VerdictAcceptModify is like VerdictAccept, but replaces the packet with a new one.
+	VerdictAcceptModify
+	// VerdictAcceptStream accepts the packet and stops processing the stream.
+	VerdictAcceptStream
+	// VerdictDrop drops the packet, but does not block the stream.
+	VerdictDrop
+	// VerdictDropStream drops the packet and blocks the stream.
+	VerdictDropStream
+)
+
+// Packet represents an IP packet.
+type Packet interface {
+	// StreamID is the ID of the stream the packet belongs to.
+	StreamID() uint32
+	// Data is the raw packet data, starting with the IP header.
+	Data() []byte
+}
+
+// PacketCallback is called for each packet received.
+// Return false to "unregister" and stop receiving packets.
+type PacketCallback func(Packet, error) bool
+
+type PacketIO interface {
+	// Register registers a callback to be called for each packet received.
+	// The callback should be called in one or more separate goroutines,
+	// and stop when the context is cancelled.
+	Register(context.Context, PacketCallback) error
+	// SetVerdict sets the verdict for a packet.
+	SetVerdict(Packet, Verdict, []byte) error
+	// ProtectedDialContext is like net.DialContext, but the connection is "protected"
+	// in the sense that the packets sent/received through the connection must bypass
+	// the packet IO and not be processed by the callback.
+	ProtectedDialContext(ctx context.Context, network, address string) (net.Conn, error)
+	// Close closes the packet IO.
+	Close() error
+}
+
+type ErrInvalidPacket struct {
+	Err error
+}
+
+func (e *ErrInvalidPacket) Error() string {
+	return "invalid packet: " + e.Err.Error()
+}