Add doppel and tls packages

mtglib/internal/tls/conn.go

@@ -0,0 +1,88 @@
+package tls
+
+import (
+	"bufio"
+	"bytes"
+
+	"github.com/9seconds/mtg/v2/essentials"
+)
+
+const (
+	SizeRecordType = 1
+	SizeVersion    = 2
+	SizeSize       = 2
+	SizeHeader     = SizeRecordType + SizeVersion + SizeSize
+
+	MaxRecordSize        = 16384
+	MaxRecordPayloadSize = MaxRecordSize - SizeHeader
+	DefaultBufferSize    = 4096
+
+	TypeChangeCipherSpec = 0x14
+	TypeHandshake        = 0x16
+	TypeApplicationData  = 0x17
+)
+
+var (
+	// TLS 1.2 is used for both TLS 1.2 and 1.3
+	TLSVersion = [SizeVersion]byte{3, 3}
+)
+
+// Conn presents an established TLS 1.3 connection, after handshake
+type Conn struct {
+	essentials.Conn
+
+	p *connPayload
+}
+
+type connPayload struct {
+	readBuf      bytes.Buffer
+	writeBuf     bytes.Buffer
+	connBuffered *bufio.Reader
+	read         bool
+	write        bool
+}
+
+func (c Conn) Write(p []byte) (int, error) {
+	if !c.p.write {
+		return c.Conn.Write(p)
+	}
+
+	return len(p), WriteRecord(c.Conn, p)
+}
+
+func (c Conn) Read(p []byte) (int, error) {
+	if !c.p.read {
+		return c.Conn.Read(p)
+	}
+
+	for {
+		if n, err := c.p.readBuf.Read(p); err == nil {
+			return n, nil
+		}
+
+		recordType, _, err := ReadRecord(c.p.connBuffered, &c.p.readBuf)
+		if err != nil {
+			return 0, err
+		}
+
+		if recordType != TypeApplicationData {
+			c.p.readBuf.Reset()
+		}
+	}
+}
+
+func New(conn essentials.Conn, read, write bool) Conn {
+	newConn := Conn{
+		Conn: conn,
+		p: &connPayload{
+			connBuffered: bufio.NewReaderSize(conn, DefaultBufferSize),
+			read:         read,
+			write:        write,
+		},
+	}
+
+	newConn.p.readBuf.Grow(DefaultBufferSize)
+	newConn.p.writeBuf.Grow(DefaultBufferSize)
+
+	return newConn
+}