feat: add platform-specific TCP timeout configurations for Darwin, FreeBSD, Windows, and Linux

pkg/interfaces/tcp_linux.go

@@ -1,32 +1,99 @@
-//go:build linux
 // +build linux
 
 package interfaces
 
 import (
+	"fmt"
+	"net"
 	"syscall"
 	"time"
 	"unsafe"
+
+	"github.com/Sudo-Ivan/reticulum-go/pkg/debug"
 )
 
+func (tc *TCPClientInterface) setTimeoutsLinux() error {
+	tcpConn, ok := tc.conn.(*net.TCPConn)
+	if !ok {
+		return fmt.Errorf("not a TCP connection")
+	}
+
+	rawConn, err := tcpConn.SyscallConn()
+	if err != nil {
+		return fmt.Errorf("failed to get raw connection: %v", err)
+	}
+
+	var sockoptErr error
+	err = rawConn.Control(func(fd uintptr) {
+		var userTimeout, probeAfter, probeInterval, probeCount int
+		
+		if tc.i2pTunneled {
+			userTimeout = I2P_USER_TIMEOUT_SEC * 1000
+			probeAfter = I2P_PROBE_AFTER_SEC
+			probeInterval = I2P_PROBE_INTERVAL_SEC
+			probeCount = I2P_PROBES_COUNT
+		} else {
+			userTimeout = TCP_USER_TIMEOUT_SEC * 1000
+			probeAfter = TCP_PROBE_AFTER_SEC
+			probeInterval = TCP_PROBE_INTERVAL_SEC
+			probeCount = TCP_PROBES_COUNT
+		}
+
+		if err := syscall.SetsockoptInt(int(fd), syscall.IPPROTO_TCP, 18, userTimeout); err != nil {
+			debug.Log(debug.DEBUG_VERBOSE, "Failed to set TCP_USER_TIMEOUT", "error", err)
+		}
+		
+		if err := syscall.SetsockoptInt(int(fd), syscall.SOL_SOCKET, syscall.SO_KEEPALIVE, 1); err != nil {
+			sockoptErr = fmt.Errorf("failed to enable SO_KEEPALIVE: %v", err)
+			return
+		}
+		
+		if err := syscall.SetsockoptInt(int(fd), syscall.IPPROTO_TCP, 4, probeAfter); err != nil {
+			debug.Log(debug.DEBUG_VERBOSE, "Failed to set TCP_KEEPIDLE", "error", err)
+		}
+		
+		if err := syscall.SetsockoptInt(int(fd), syscall.IPPROTO_TCP, 5, probeInterval); err != nil {
+			debug.Log(debug.DEBUG_VERBOSE, "Failed to set TCP_KEEPINTVL", "error", err)
+		}
+		
+		if err := syscall.SetsockoptInt(int(fd), syscall.IPPROTO_TCP, 6, probeCount); err != nil {
+			debug.Log(debug.DEBUG_VERBOSE, "Failed to set TCP_KEEPCNT", "error", err)
+		}
+	})
+
+	if err != nil {
+		return fmt.Errorf("control failed: %v", err)
+	}
+	if sockoptErr != nil {
+		return sockoptErr
+	}
+
+	debug.Log(debug.DEBUG_VERBOSE, "TCP keepalive configured (Linux)", "i2p", tc.i2pTunneled)
+	return nil
+}
+
+func (tc *TCPClientInterface) setTimeoutsOSX() error {
+	return tc.setTimeoutsLinux()
+}
+
 func platformGetRTT(fd uintptr) time.Duration {
 	var info syscall.TCPInfo
-	size := uint32(syscall.SizeofTCPInfo)
-
-	_, _, err := syscall.Syscall6(
+	infoLen := uint32(unsafe.Sizeof(info))
+	
+	// TCP_INFO is 11 on Linux
+	_, _, errno := syscall.Syscall6(
 		syscall.SYS_GETSOCKOPT,
 		fd,
-		syscall.SOL_TCP,
-		syscall.TCP_INFO,
-		uintptr(unsafe.Pointer(&info)), // #nosec G103
-		uintptr(unsafe.Pointer(&size)), // #nosec G103
+		syscall.IPPROTO_TCP,
+		11, // TCP_INFO
+		uintptr(unsafe.Pointer(&info)),
+		uintptr(unsafe.Pointer(&infoLen)),
 		0,
 	)
-
-	if err != 0 {
+	
+	if errno != 0 {
 		return 0
 	}
-
-	// RTT is in microseconds, convert to Duration
+	
 	return time.Duration(info.Rtt) * time.Microsecond
 }