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authorAdam Ierymenko <adam.ierymenko@gmail.com>2013-08-30 16:47:54 -0400
committerAdam Ierymenko <adam.ierymenko@gmail.com>2013-08-30 16:47:54 -0400
commit1a7e303f97507842c1a0bfffb27b76277bd43bab (patch)
tree46405b12a021d3d95eddc568708e609c5569a81a /node
parent9ca521e89485c9c5b06909b1c8d8ef5ac3b24f4e (diff)
downloadinfinitytier-1a7e303f97507842c1a0bfffb27b76277bd43bab.tar.gz
infinitytier-1a7e303f97507842c1a0bfffb27b76277bd43bab.zip
docs and minor cleanup
Diffstat (limited to 'node')
-rw-r--r--node/BloomFilter.hpp2
-rw-r--r--node/Multicaster.hpp2
-rw-r--r--node/RateLimiter.hpp35
3 files changed, 20 insertions, 19 deletions
diff --git a/node/BloomFilter.hpp b/node/BloomFilter.hpp
index f3071c0a..4c52525e 100644
--- a/node/BloomFilter.hpp
+++ b/node/BloomFilter.hpp
@@ -38,7 +38,7 @@ namespace ZeroTier {
*
* This actually isn't a total filter, in that it does not contain a hashing
* algorithm. It's up to the caller to hash/sum the items being remembered
- * so that the distribution of 'n' is random.
+ * so that the distribution of 'n' is random across the filter's size range.
*
* @tparam B Size in BITS, must be a multiple of 8
*/
diff --git a/node/Multicaster.hpp b/node/Multicaster.hpp
index 80d16688..58bfeed1 100644
--- a/node/Multicaster.hpp
+++ b/node/Multicaster.hpp
@@ -380,7 +380,7 @@ private:
// network ID and a multicast group within that network.
typedef std::pair<uint64_t,MulticastGroup> MulticastChannel;
- // Address and time of last LIKE
+ // A membership in a multicast channel, an address and time of last LIKE
typedef std::pair<Address,uint64_t> MulticastMembership;
// Network : MulticastGroup -> vector<Address : time of last LIKE>
diff --git a/node/RateLimiter.hpp b/node/RateLimiter.hpp
index 2526da48..59dd8d28 100644
--- a/node/RateLimiter.hpp
+++ b/node/RateLimiter.hpp
@@ -41,29 +41,28 @@
namespace ZeroTier {
/**
- * Burstable rate limiter
+ * Data transfer accounting used for multicast groups
*
- * This limits a transfer rate to a maximum bytes per second using an
- * accounting method based on a balance rather than accumulating an
- * average rate. The result is a burstable rate limit rather than a
- * continuous rate limit; the link being limited may use all its balance
- * at once or slowly over time. Balance constantly replenishes over time
- * up to a configurable maximum balance.
+ * This is used to apply a bank account model to multicast groups. Each
+ * multicast packet counts against a balance, which accrues at a given
+ * rate in bytes per second. Debt is possible. These parameters are
+ * configurable.
+ *
+ * A bank account model permits bursting behavior, which correctly models
+ * how OSes and apps typically use multicast. It's common for things to
+ * spew lots of multicast messages at once, wait a while, then do it
+ * again. A consistent bandwidth limit model doesn't fit.
*/
class RateLimiter
{
public:
/**
- * Limits to apply to a rate limiter
- *
- * Since many rate limiters may share the same fixed limit values,
- * save memory by breaking this out into a struct parameter that
- * can be passed into RateLimiter's methods.
+ * Rate and min/max to apply on rate limiter update
*/
- struct Limit
+ struct Rate
{
/**
- * Speed in bytes per second, or rate of balance accrual
+ * Rate of balance accrual in bytes per second
*/
double bytesPerSecond;
@@ -86,6 +85,8 @@ public:
RateLimiter() throw() {}
/**
+ * Create an initialize rate limiter
+ *
* @param preload Initial balance to place in account
*/
RateLimiter(double preload)
@@ -107,18 +108,18 @@ public:
}
/**
- * Update balance based on current clock and supplied Limit
+ * Update balance based on current clock and supplied rate
*
* @param lim Current limits in effect
* @param deduct Amount to deduct, or 0.0 to just update
* @return New balance with deduction applied
*/
- inline double update(const Limit &lim,double deduct)
+ inline double update(const Rate &r,double deduct)
throw()
{
double lt = _lastTime;
double now = _lastTime = Utils::nowf();
- return (_balance = fmax(lim.minBalance,fmin(lim.maxBalance,(_balance + (lim.bytesPerSecond * (now - lt))) - deduct)));
+ return (_balance = fmax(r.minBalance,fmin(r.maxBalance,(_balance + (r.bytesPerSecond * (now - lt))) - deduct)));
}
private: