1 files changed, 81 insertions, 0 deletions
diff --git a/extendedstats/darwin.go b/extendedstats/darwin.go
new file mode 100644
index 0000000..788e36c
--- /dev/null
+++ b/extendedstats/darwin.go
@@ -0,0 +1,81 @@
+//go:build darwin
+// +build darwin
+
+package extendedstats
+
+import (
+	"crypto/tls"
+	"fmt"
+	"net"
+
+	"github.com/network-quality/goresponsiveness/utilities"
+	"golang.org/x/sys/unix"
+)
+
+type ExtendedStats struct {
+	Maxseg               uint64
+	MaxSendMss           uint64
+	MaxRecvMss           uint64
+	TotalRetransmissions uint64
+	totalSent            uint64
+	TotalReorderings     uint64
+	AverageRtt           float64
+	rtt_measurements     uint64
+	total_rtt            float64
+	RetransmitRatio      float64
+}
+
+func ExtendedStatsAvailable() bool {
+	return true
+}
+
+func (es *ExtendedStats) IncorporateConnectionStats(rawConn net.Conn) error {
+	tlsConn, ok := rawConn.(*tls.Conn)
+	if !ok {
+		return fmt.Errorf("OOPS: Could not get the TCP info for the connection (not a TLS connection)!\n")
+	}
+	tcpConn, ok := tlsConn.NetConn().(*net.TCPConn)
+	if !ok {
+		return fmt.Errorf("OOPS: Could not get the TCP info for the connection (not a TCP connection)!\n")
+	}
+	if info, err := getTCPConnectionInfo(tcpConn); err != nil {
+		return fmt.Errorf("OOPS: Could not get the TCP info for the connection: %v!\n", err)
+	} else {
+		es.Maxseg = utilities.Max(es.Maxseg, uint64(info.Maxseg))
+		es.TotalReorderings += info.Rxoutoforderbytes
+		es.TotalRetransmissions += info.Txretransmitbytes
+		es.totalSent += info.Txbytes
+		es.total_rtt += float64(info.Srtt)
+		es.rtt_measurements += 1
+		es.AverageRtt = es.total_rtt / float64(es.rtt_measurements)
+		es.RetransmitRatio = (float64(es.TotalRetransmissions) / float64(es.totalSent)) * 100.0
+	}
+	return nil
+}
+
+func (es *ExtendedStats) Repr() string {
+	return fmt.Sprintf(`Extended Statistics:
+	Maximum Segment Size: %v
+	Total Bytes Retransmitted: %v
+	Retransmission Ratio: %.2f%%
+	Total Bytes Reordered: %v
+	Average RTT: %v
+`, es.Maxseg, es.TotalRetransmissions, es.RetransmitRatio, es.TotalReorderings, es.AverageRtt)
+}
+
+func getTCPConnectionInfo(connection net.Conn) (*unix.TCPConnectionInfo, error) {
+	tcpConn, ok := connection.(*net.TCPConn)
+	if !ok {
+		return nil, fmt.Errorf("connection is not a net.TCPConn")
+	}
+	rawConn, err := tcpConn.SyscallConn()
+	if err != nil {
+		return nil, err
+	}
+
+	var info *unix.TCPConnectionInfo = nil
+	rawConn.Control(func(fd uintptr) {
+		info, err = unix.GetsockoptTCPConnectionInfo(int(fd), unix.IPPROTO_TCP, unix.TCP_CONNECTION_INFO)
+	})
+	return info, err
+}