fshttp: add DSCP support with --dscp for QoS with differentiated services

fs/config/configflags/configflags.go

@@ -7,6 +7,7 @@ import (
 	"log"
 	"net"
 	"path/filepath"
+	"strconv"
 	"strings"
 
 	"github.com/rclone/rclone/fs"
@@ -29,6 +30,7 @@ var (
 	deleteAfter     bool
 	bindAddr        string
 	disableFeatures string
+	dscp            string
 	uploadHeaders   []string
 	downloadHeaders []string
 	headers         []string
@@ -125,6 +127,7 @@ func AddFlags(ci *fs.ConfigInfo, flagSet *pflag.FlagSet) {
 	flags.StringArrayVarP(flagSet, &headers, "header", "", nil, "Set HTTP header for all transactions")
 	flags.BoolVarP(flagSet, &ci.RefreshTimes, "refresh-times", "", ci.RefreshTimes, "Refresh the modtime of remote files.")
 	flags.BoolVarP(flagSet, &ci.NoConsole, "no-console", "", ci.NoConsole, "Hide console window. Supported on Windows only.")
+	flags.StringVarP(flagSet, &dscp, "dscp", "", "", "Set DSCP value to connections. Can be value or names, eg. CS1, LE, DF, AF21.")
 }
 
 // ParseHeaders converts the strings passed in via the header flags into HTTPOptions
@@ -254,6 +257,13 @@ func SetFlags(ci *fs.ConfigInfo) {
 	if len(headers) != 0 {
 		ci.Headers = ParseHeaders(headers)
 	}
+	if len(dscp) != 0 {
+		if value, ok := parseDSCP(dscp); ok {
+			ci.TrafficClass = value << 2
+		} else {
+			log.Fatalf("--dscp: Invalid DSCP name: %v", dscp)
+		}
+	}
 
 	// Make the config file absolute
 	configPath, err := filepath.Abs(config.ConfigPath)
@@ -266,3 +276,61 @@ func SetFlags(ci *fs.ConfigInfo) {
 	ci.MultiThreadSet = multiThreadStreamsFlag != nil && multiThreadStreamsFlag.Changed
 
 }
+
+// parseHeaders converts DSCP names to value
+func parseDSCP(dscp string) (uint8, bool) {
+	if s, err := strconv.ParseUint(dscp, 10, 6); err == nil {
+		return uint8(s), true
+	}
+	dscp = strings.ToUpper(dscp)
+	switch dscp {
+	case "BE":
+		fallthrough
+	case "DF":
+		fallthrough
+	case "CS0":
+		return 0x00, true
+	case "CS1":
+		return 0x08, true
+	case "AF11":
+		return 0x0A, true
+	case "AF12":
+		return 0x0C, true
+	case "AF13":
+		return 0x0E, true
+	case "CS2":
+		return 0x10, true
+	case "AF21":
+		return 0x12, true
+	case "AF22":
+		return 0x14, true
+	case "AF23":
+		return 0x16, true
+	case "CS3":
+		return 0x18, true
+	case "AF31":
+		return 0x1A, true
+	case "AF32":
+		return 0x1C, true
+	case "AF33":
+		return 0x1E, true
+	case "CS4":
+		return 0x20, true
+	case "AF41":
+		return 0x22, true
+	case "AF42":
+		return 0x24, true
+	case "AF43":
+		return 0x26, true
+	case "CS5":
+		return 0x28, true
+	case "EF":
+		return 0x2E, true
+	case "CS6":
+		return 0x30, true
+	case "LE":
+		return 0x01, true
+	default:
+		return 0, false
+	}
+}