[Bugfix] Dereference nil when type assertions failed in IncorporateConnectionStats

Errors as a result of failed type assertions in
IncorporateConnectionStats were caught/logged but there was no
function-termination control flow associated with these error
conditions. As a result, control would continue and cause problems. This
patch fixes that.

3 files changed, 12 insertions, 8 deletions

diff --git a/extendedstats/other.go b/extendedstats/other.go
index 825ea95..369c8f6 100644
--- a/extendedstats/other.go
+++ b/extendedstats/other.go
@@ -9,7 +9,9 @@ import (
 
 type ExtendedStats struct{}
 
-func (es *ExtendedStats) IncorporateConnectionStats(conn net.Conn) {}
+func (es *ExtendedStats) IncorporateConnectionStats(conn net.Conn) error {
+	return fmt.Errorf("OOPS: IncorporateConnectionStats is not supported on this platform.")
+}
 
 func (es *ExtendedStats) Repr() string {
 	return ""
diff --git a/extendedstats/unix.go b/extendedstats/unix.go
index c4dc065..fb4a2c8 100644
--- a/extendedstats/unix.go
+++ b/extendedstats/unix.go
@@ -1,5 +1,5 @@
 //go:build dragonfly || freebsd || linux || netbsd || openbsd
-// +build  dragonfly freebsd linux netbsd openbsd
+// +build dragonfly freebsd linux netbsd openbsd
 
 package extendedstats
 
@@ -24,17 +24,17 @@ func ExtendedStatsAvailable() bool {
 	return true
 }
 
-func (es *ExtendedStats) IncorporateConnectionStats(rawConn net.Conn) {
+func (es *ExtendedStats) IncorporateConnectionStats(rawConn net.Conn) error {
 	tlsConn, ok := rawConn.(*tls.Conn)
 	if !ok {
-		fmt.Printf("OOPS: Could not get the TCP info for the connection (not a TLS connection)!\n")
+		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 {
-		fmt.Printf("OOPS: Could not get the TCP info for the connection (not a TCP connection)!\n")
+		return fmt.Errorf("OOPS: Could not get the TCP info for the connection (not a TCP connection)!\n")
 	}
 	if info, err := getTCPInfo(tcpConn); err != nil {
-		fmt.Printf("OOPS: Could not get the TCP info for the connection: %v!\n", err)
+		return fmt.Errorf("OOPS: Could not get the TCP info for the connection: %v!\n", err)
 	} else {
 		es.MaxPathMtu = utilities.Max(es.MaxPathMtu, uint64(info.Pmtu))
 		// https://lkml.iu.edu/hypermail/linux/kernel/1705.0/01790.html
@@ -42,8 +42,8 @@ func (es *ExtendedStats) IncorporateConnectionStats(rawConn net.Conn) {
 		es.total_rtt += float64(info.Rtt)
 		es.rtt_measurements += 1
 		es.AverageRtt = es.total_rtt / float64(es.rtt_measurements)
-
 	}
+	return nil
 }
 
 func (es *ExtendedStats) Repr() string {
diff --git a/networkQuality.go b/networkQuality.go
index e5e3631..c7dd74b 100644
--- a/networkQuality.go
+++ b/networkQuality.go
@@ -313,7 +313,9 @@ func main() {
 			if !extendedstats.ExtendedStatsAvailable() {
 				panic("Extended stats are not available but the user requested their calculation.")
 			}
-			extendedStats.IncorporateConnectionStats(downloadSaturation.LGCs[i].Stats().ConnInfo.Conn)
+			if err := extendedStats.IncorporateConnectionStats(downloadSaturation.LGCs[i].Stats().ConnInfo.Conn); err != nil {
+				fmt.Fprintf(os.Stderr, "Warning: Could not add extended stats for the connection: %v", err)
+			}
 		}
 	}