Method writeHandshakeResponsePacket

packets.go:321–415

Client Authentication Packet https://dev.mysql.com/doc/dev/mysql-server/latest/page_protocol_connection_phase_packets_protocol_handshake_response.html

(authResp []byte, plugin string)

// Client Authentication Packet
// https://dev.mysql.com/doc/dev/mysql-server/latest/page_protocol_connection_phase_packets_protocol_handshake_response.html
func (mc *mysqlConn) writeHandshakeResponsePacket(authResp []byte, plugin string) error {
	// packet header  4
	// capabilities   4
	// maxPacketSize  4
	// collation id   1
	// filler        23
	data, err := mc.buf.takeSmallBuffer(4*3 + 24)
	if err != nil {
		mc.cleanup()
		return err
	}
	_ = data[4*3+23] // boundery check

	// clientCapabilities [32 bit]
	binary.LittleEndian.PutUint32(data[4:], uint32(mc.capabilities))

	// MaxPacketSize [32 bit] (none)
	binary.LittleEndian.PutUint32(data[8:], 0)

	// Collation ID [1 byte]
	data[12] = defaultCollationID
	if cname := mc.cfg.Collation; cname != "" {
		colID, ok := collations[cname]
		if ok {
			data[12] = colID
		} else if len(mc.cfg.charsets) > 0 {
			// When cfg.charset is set, the collation is set by `SET NAMES <charset> COLLATE <collation>`.
			return fmt.Errorf("unknown collation: %q", cname)
		}
	}

	// Filler [23 bytes] (all 0x00)
	// or filler 19bytes + mariadb extCapabilities
	pos := 13
	if mc.capabilities&clientMySQL == 0 {
		for ; pos < 13+19; pos++ {
			data[pos] = 0
		}
		// MariaDB Extended Capabilities
		binary.LittleEndian.PutUint32(data[13+19:], uint32(mc.extCapabilities))
	} else {
		for ; pos < 13+23; pos++ {
			data[pos] = 0
		}
	}

	// SSL Connection Request Packet
	// https://dev.mysql.com/doc/dev/mysql-server/latest/page_protocol_connection_phase_packets_protocol_ssl_request.html
	// https://mariadb.com/kb/en/connection/#sslrequest-packet
	if mc.cfg.TLS != nil {
		// Send TLS / SSL request packet
		if err := mc.writePacket(data); err != nil {
			return err
		}

		// Switch to TLS
		tlsConn := tls.Client(mc.netConn, mc.cfg.TLS)
		if err := tlsConn.Handshake(); err != nil {