Rollback new routing functionality (#1805)

util/net/net_linux.go

@@ -1,35 +0,0 @@
-//go:build !android
-
-package net
-
-import (
-	"fmt"
-	"syscall"
-)
-
-// SetSocketMark sets the SO_MARK option on the given socket connection
-func SetSocketMark(conn syscall.Conn) error {
-	sysconn, err := conn.SyscallConn()
-	if err != nil {
-		return fmt.Errorf("get raw conn: %w", err)
-	}
-
-	return SetRawSocketMark(sysconn)
-}
-
-func SetRawSocketMark(conn syscall.RawConn) error {
-	var setErr error
-
-	err := conn.Control(func(fd uintptr) {
-		setErr = syscall.SetsockoptInt(int(fd), syscall.SOL_SOCKET, syscall.SO_MARK, NetbirdFwmark)
-	})
-	if err != nil {
-		return fmt.Errorf("control: %w", err)
-	}
-
-	if setErr != nil {
-		return fmt.Errorf("set SO_MARK: %w", setErr)
-	}
-
-	return nil
-}