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Revise peer path weighting to always prioritize cluster-optimal paths.

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This commit is contained in:
Adam Ierymenko 2016-04-19 09:22:51 -07:00
parent cecfa99b7b
commit 4c455876f9
6 changed files with 107 additions and 50 deletions
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71
node/Path.hpp
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@ -31,13 +31,21 @@
/**
* Flag indicating that this path is suboptimal
*
* This is used in cluster mode to indicate that the peer has been directed
* to a better path. This path can continue to be used but shouldn't be kept
* or advertised to other cluster members. Not used if clustering is not
* built and enabled.
* Clusters set this flag on remote paths if GeoIP or other routing decisions
* indicate that a peer should be handed off to another cluster member.
*/
#define ZT_PATH_FLAG_CLUSTER_SUBOPTIMAL 0x0001
/**
* Flag indicating that this path is optimal
*
* Peers set this flag on paths that are pushed by a cluster and indicated as
* optimal. A second flag is needed since we want to prioritize cluster optimal
* paths and de-prioritize sub-optimal paths and for new paths we don't know
* which one they are. So we want a trinary state: optimal, suboptimal, unknown.
*/
#define ZT_PATH_FLAG_CLUSTER_OPTIMAL 0x0002
/**
* Maximum return value of preferenceRank()
*/
@ -176,17 +184,39 @@ public:
*/
inline InetAddress::IpScope ipScope() const throw() { return _ipScope; }
/**
* @param f Valuve of ZT_PATH_FLAG_CLUSTER_SUBOPTIMAL and inverse of ZT_PATH_FLAG_CLUSTER_OPTIMAL (both are changed)
*/
inline void setClusterSuboptimal(bool f)
{
if (f) {
_flags = (_flags | ZT_PATH_FLAG_CLUSTER_SUBOPTIMAL) & ~ZT_PATH_FLAG_CLUSTER_OPTIMAL;
} else {
_flags = (_flags | ZT_PATH_FLAG_CLUSTER_OPTIMAL) & ~ZT_PATH_FLAG_CLUSTER_SUBOPTIMAL;
}
}
/**
* @return True if ZT_PATH_FLAG_CLUSTER_SUBOPTIMAL is set
*/
inline bool isClusterSuboptimal() const { return ((_flags & ZT_PATH_FLAG_CLUSTER_SUBOPTIMAL) != 0); }
/**
* @return True if ZT_PATH_FLAG_CLUSTER_OPTIMAL is set
*/
inline bool isClusterOptimal() const { return ((_flags & ZT_PATH_FLAG_CLUSTER_OPTIMAL) != 0); }
/**
* @return Preference rank, higher == better (will be less than 255)
*/
inline unsigned int preferenceRank() const throw()
{
// First, since the scope enum values in InetAddress.hpp are in order of
// use preference rank, we take that. Then we multiple by two, yielding
// a sequence like 0, 2, 4, 6, etc. Then if it's IPv6 we add one. This
// makes IPv6 addresses of a given scope outrank IPv4 addresses of the
// same scope -- e.g. 1 outranks 0. This makes us prefer IPv6, but not
// if the address scope/class is of a fundamentally lower rank.
/* First, since the scope enum values in InetAddress.hpp are in order of
* use preference rank, we take that. Then we multiple by two, yielding
* a sequence like 0, 2, 4, 6, etc. Then if it's IPv6 we add one. This
* makes IPv6 addresses of a given scope outrank IPv4 addresses of the
* same scope -- e.g. 1 outranks 0. This makes us prefer IPv6, but not
* if the address scope/class is of a fundamentally lower rank. */
return ( ((unsigned int)_ipScope << 1) | (unsigned int)(_addr.ss_family == AF_INET6) );
}
@ -199,8 +229,13 @@ public:
* received something) scaled/corrected by the preference rank within the
* ping keepalive window. That way higher ranking paths are preferred but
* not to the point of overriding timeouts and choosing potentially dead
* paths. */
return (_lastReceived + (preferenceRank() * (ZT_PEER_DIRECT_PING_DELAY / ZT_PATH_MAX_PREFERENCE_RANK)));
* paths. Finally we increase the score for known to be cluster optimal
* paths and decrease it for paths known to be suboptimal. */
uint64_t score = _lastReceived + ZT_PEER_DIRECT_PING_DELAY; // make sure it's never less than ZT_PEER_DIRECT_PING_DELAY to prevent integer underflow
score += preferenceRank() * (ZT_PEER_DIRECT_PING_DELAY / ZT_PATH_MAX_PREFERENCE_RANK);
score += (uint64_t)(_flags & ZT_PATH_FLAG_CLUSTER_OPTIMAL) * (ZT_PEER_DIRECT_PING_DELAY / 2); // /2 because CLUSTER_OPTIMAL is flag 0x0002
score -= (uint64_t)(_flags & ZT_PATH_FLAG_CLUSTER_SUBOPTIMAL) * ZT_PEER_DIRECT_PING_DELAY;
return score;
}
/**
@ -259,18 +294,6 @@ public:
return false;
}
#ifdef ZT_ENABLE_CLUSTER
/**
* @param f New value of ZT_PATH_FLAG_CLUSTER_SUBOPTIMAL
*/
inline void setClusterSuboptimal(bool f) { _flags = ((f) ? (_flags | ZT_PATH_FLAG_CLUSTER_SUBOPTIMAL) : (_flags & (~ZT_PATH_FLAG_CLUSTER_SUBOPTIMAL))); }
/**
* @return True if ZT_PATH_FLAG_CLUSTER_SUBOPTIMAL is set
*/
inline bool isClusterSuboptimal() const { return ((_flags & ZT_PATH_FLAG_CLUSTER_SUBOPTIMAL) != 0); }
#endif
/**
* @return Current path probation count (for dead path detect)
*/