[Feature] Access TCP_INFO about underlying TCP connections

This will only work on *nix systems. Code that displays information
in this PR is only exemplary -- I am sure that there are better
places in the code to display it!

1 files changed, 54 insertions, 0 deletions

diff --git a/utilities/utilities.go b/utilities/utilities.go
index a143d31..e4c8a0d 100644
--- a/utilities/utilities.go
+++ b/utilities/utilities.go
@@ -18,10 +18,13 @@ import (
 	"fmt"
 	"math"
 	"math/rand"
+	"net"
 	"os"
 	"reflect"
 	"sync/atomic"
 	"time"
+
+	"golang.org/x/sys/unix"
 )
 
 func IsInterfaceNil(ifc interface{}) bool {
@@ -122,3 +125,54 @@ func (optional Optional[S]) String() string {
 func RandBetween(max int) int {
 	return rand.New(rand.NewSource(int64(time.Now().Nanosecond()))).Int() % max
 }
+
+func GetTCPInfo(connection net.Conn) (*unix.TCPInfo, 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.TCPInfo = nil
+	rawConn.Control(func(fd uintptr) {
+		info, err = unix.GetsockoptTCPInfo(int(fd), unix.SOL_TCP, unix.TCP_INFO)
+	})
+	return info, err
+}
+
+func PrintTCPInfo(info *unix.TCPInfo) {
+	fmt.Printf("TCPInfo: \n")
+	fmt.Printf("	State: %v\n", info.State)
+	fmt.Printf("	Ca_state: %v\n", info.Ca_state)
+	fmt.Printf("	Retransmits: %v\n", info.Retransmits)
+	fmt.Printf("	Probes: %v\n", info.Probes)
+	fmt.Printf("	Backoff: %v\n", info.Backoff)
+	fmt.Printf("	Options: %v\n", info.Options)
+	fmt.Printf("	Rto: %v\n", info.Rto)
+	fmt.Printf("	Ato: %v\n", info.Ato)
+	fmt.Printf("	Snd_mss: %v\n", info.Snd_mss)
+	fmt.Printf("	Rcv_mss: %v\n", info.Rcv_mss)
+	fmt.Printf("	Unacked: %v\n", info.Unacked)
+	fmt.Printf("	Sacked: %v\n", info.Sacked)
+	fmt.Printf("	Lost: %v\n", info.Lost)
+	fmt.Printf("	Retrans: %v\n", info.Retrans)
+	fmt.Printf("	Fackets: %v\n", info.Fackets)
+	fmt.Printf("	Last_data_sent: %v\n", info.Last_data_sent)
+	fmt.Printf("	Last_ack_sent: %v\n", info.Last_ack_sent)
+	fmt.Printf("	Last_data_recv: %v\n", info.Last_data_recv)
+	fmt.Printf("	Last_ack_recv: %v\n", info.Last_ack_recv)
+	fmt.Printf("	Pmtu: %v\n", info.Pmtu)
+	fmt.Printf("	Rcv_ssthresh: %v\n", info.Rcv_ssthresh)
+	fmt.Printf("	Rtt: %v\n", info.Rtt)
+	fmt.Printf("	Rttvar: %v\n", info.Rttvar)
+	fmt.Printf("	Snd_ssthresh: %v\n", info.Snd_ssthresh)
+	fmt.Printf("	Snd_cwnd: %v\n", info.Snd_cwnd)
+	fmt.Printf("	Advmss: %v\n", info.Advmss)
+	fmt.Printf("	Reordering: %v\n", info.Reordering)
+	fmt.Printf("	Rcv_rtt: %v\n", info.Rcv_rtt)
+	fmt.Printf("	Rcv_space: %v\n", info.Rcv_space)
+	fmt.Printf("	Total_retrans: %v\n", info.Total_retrans)
+}