Add call protocol, Rmux. Update AmneziaWG. Fixes and improvements

transport/call/common/jitter.go

@@ -0,0 +1,40 @@
+package common
+
+import (
+	"math/rand/v2"
+	"time"
+)
+
+const backoffJitterFloorDivisor = 4
+
+func BackoffWithJitter(attempt int, initialDelay, maxDelay time.Duration) time.Duration {
+	if initialDelay <= 0 {
+		return 0
+	}
+	if maxDelay < initialDelay {
+		maxDelay = initialDelay
+	}
+	if attempt < 0 {
+		attempt = 0
+	}
+	ceiling := maxDelay
+	if shifted := initialDelay << uint(attempt); shifted > 0 && shifted < maxDelay {
+		ceiling = shifted
+	}
+	floor := ceiling / backoffJitterFloorDivisor
+	return floor + time.Duration(rand.Int64N(int64(ceiling-floor)+1))
+}
+
+func DurationInRange(minDuration, maxDuration time.Duration) time.Duration {
+	if maxDuration <= minDuration {
+		return minDuration
+	}
+	return minDuration + time.Duration(rand.Int64N(int64(maxDuration-minDuration)+1))
+}
+
+func IntInRange(minValue, maxValue int) int {
+	if maxValue <= minValue {
+		return minValue
+	}
+	return minValue + rand.IntN(maxValue-minValue+1)
+}