padding turn %d combines variants with a send range

Error message

padding turn %d combines variants with a send range

What it means

Error "padding turn %d combines variants with a send range" thrown in XTLS/Xray-core.

Source

Thrown at transport/internet/finalmask/xmc/padding.go:108

		}
		if err := validatePaddingDelayRange(turn.chunkDelay); err != nil {
			return fmt.Errorf("padding turn %d has an invalid chunk delay: %w", i, err)
		}
		if turn.writeChunkMinLength < 0 || turn.writeChunkLength < turn.writeChunkMinLength || turn.writeChunkLength > maxPaddingChunkLength {
			return fmt.Errorf("padding turn %d has an invalid write chunk range: %d-%d", i, turn.writeChunkMinLength, turn.writeChunkLength)
		}
		if len(turn.variants) > 0 && turn.writeChunkLength != 0 {
			return fmt.Errorf("padding turn %d combines variants with generated write chunks", i)
		}

		minLength, maxLength, err := paddingTurnBounds(turn)
		if err != nil {
			return fmt.Errorf("padding turn %d: %w", i, err)
		}
		hasSendRange := turn.sendMinLength != 0 || turn.sendMaxLength != 0
		if hasSendRange {
			if len(turn.variants) > 0 {
				return fmt.Errorf("padding turn %d combines variants with a send range", i)
			}
			if turn.sendMinLength < minLength || turn.sendMaxLength < turn.sendMinLength || turn.sendMaxLength > maxLength {
				return fmt.Errorf("padding turn %d has an invalid send range: %d-%d", i, turn.sendMinLength, turn.sendMaxLength)
			}
		}
		if i == 0 && minLength-firstTurnPrefixLength < 1 {
			return fmt.Errorf("padding turn 0 is too short for %d prefix bytes", firstTurnPrefixLength)
		}
		if i == 0 && len(turn.variants) > 0 {
			for j, variant := range turn.variants {
				if _, _, err = trimPaddingPrefix(variant, firstTurnPrefixLength); err != nil {
					return fmt.Errorf("padding turn 0 variant %d: %w", j, err)
				}
			}
		}
		if i > 0 && turn.direction == schedule[i-1].direction {
			return fmt.Errorf("padding turns %d and %d have the same direction", i-1, i)
		}

View on GitHub (pinned to 7d214f8b09)

When it happens

Trigger: Thrown at transport/internet/finalmask/xmc/padding.go:108 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of XTLS/Xray-core@7d214f8b09 (2026-08-15). Data as JSON: /api/errors/19b2656133286bd9. Report an issue: GitHub.