/*
* ZeroTier One - Network Virtualization Everywhere
* Copyright (C) 2011-2016 ZeroTier, Inc. https://www.zerotier.com/
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef ZT_CLUSTER_HPP
#define ZT_CLUSTER_HPP
#ifdef ZT_ENABLE_CLUSTER
#include <map>
#include "Constants.hpp"
#include "../include/ZeroTierOne.h"
#include "Address.hpp"
#include "InetAddress.hpp"
#include "SHA512.hpp"
#include "Utils.hpp"
#include "Buffer.hpp"
#include "Mutex.hpp"
#include "SharedPtr.hpp"
#include "Hashtable.hpp"
#include "Packet.hpp"
#include "SharedPtr.hpp"
/**
* Timeout for cluster members being considered "alive"
*
* A cluster member is considered dead and will no longer have peers
* redirected to it if we have not heard a heartbeat in this long.
*/
#define ZT_CLUSTER_TIMEOUT 5000
/**
* Desired period between doPeriodicTasks() in milliseconds
*/
#define ZT_CLUSTER_PERIODIC_TASK_PERIOD 20
/**
* How often to flush outgoing message queues (maximum interval)
*/
#define ZT_CLUSTER_FLUSH_PERIOD ZT_CLUSTER_PERIODIC_TASK_PERIOD
/**
* Maximum number of queued outgoing packets per sender address
*/
#define ZT_CLUSTER_MAX_QUEUE_PER_SENDER 16
/**
* Expiration time for send queue entries
*/
#define ZT_CLUSTER_QUEUE_EXPIRATION 3000
/**
* Chunk size for allocating queue entries
*
* Queue entries are allocated in chunks of this many and are added to a pool.
* ZT_CLUSTER_MAX_QUEUE_GLOBAL must be evenly divisible by this.
*/
#define ZT_CLUSTER_QUEUE_CHUNK_SIZE 32
/**
* Maximum number of chunks to ever allocate
*
* This is a global sanity limit to prevent resource exhaustion attacks. It
* works out to about 600mb of RAM. You'll never see this on a normal edge
* node. We're unlikely to see this on a root server unless someone is DOSing
* us. In that case cluster relaying will be affected but other functions
* should continue to operate normally.
*/
#define ZT_CLUSTER_MAX_QUEUE_CHUNKS 8194
/**
* Max data per queue entry
*/
#define ZT_CLUSTER_SEND_QUEUE_DATA_MAX 1500
namespace ZeroTier {
class RuntimeEnvironment;
class MulticastGroup;
class Peer;
class Identity;
// Internal class implemented inside Cluster.cpp
class _ClusterSendQueue;
/**
* Multi-homing cluster state replication and packet relaying
*
* Multi-homing means more than one node sharing the same ZeroTier identity.
* There is nothing in the protocol to prevent this, but to make it work well
* requires the devices sharing an identity to cooperate and share some
* information.
*
* There are three use cases we want to fulfill:
*
* (1) Multi-homing of root servers with handoff for efficient routing,
* HA, and load balancing across many commodity nodes.
* (2) Multi-homing of network controllers for the same reason.
* (3) Multi-homing of nodes on virtual networks, such as domain servers
* and other important endpoints.
*
* These use cases are in order of escalating difficulty. The initial
* version of Cluster is aimed at satisfying the first, though you are
* free to try #2 and #3.
*/
class Cluster
{
public:
/**
* State message types
*/
enum StateMessageType
{
CLUSTER_MESSAGE_NOP = 0,
/**
* This cluster member is alive:
* <[2] version minor>
* <[2] version major>
* <[2] version revision>
* <[1] protocol version>
* <[4] X location (signed 32-bit)>
* <[4] Y location (signed 32-bit)>
* <[4] Z location (signed 32-bit)>
* <[8] local clock at this member>
* <[8] load average>
* <[8] number of peers>
* <[8] flags (currently unused, must be zero)>
* <[1] number of preferred ZeroTier endpoints>
* <[...] InetAddress(es) of preferred ZeroTier endpoint(s)>
*
* Cluster members constantly broadcast an alive heartbeat and will only
* receive peer redirects if they've done so within the timeout.
*/
CLUSTER_MESSAGE_ALIVE = 1,
/**
* Cluster member has this peer:
* <[...] serialized identity of peer>
*
* This is typically sent in response to WANT_PEER but can also be pushed
* to prepopulate if this makes sense.
*/
CLUSTER_MESSAGE_HAVE_PEER = 2,
/**
* Cluster member wants this peer:
* <[5] ZeroTier address of peer>
*
* Members that have a direct link to this peer will respond with
* HAVE_PEER.
*/
CLUSTER_MESSAGE_WANT_PEER = 3,
/**
* A remote packet that we should also possibly respond to:
* <[2] 16-bit length of remote packet>
* <[...] remote packet payload>
*
* Cluster members may relay requests by relaying the request packet.
* These may include requests such as WHOIS and MULTICAST_GATHER. The
* packet must be already decrypted, decompressed, and authenticated.
*
* This can only be used for small request packets as per the cluster
* message size limit, but since these are the only ones in question
* this is fine.
*
* If a response is generated it is sent via PROXY_SEND.
*/
CLUSTER_MESSAGE_REMOTE_PACKET = 4,
/**
* Request that VERB_RENDEZVOUS be sent to a peer that we have:
* <[5] ZeroTier address of peer on recipient's side>
* <[5] ZeroTier address of peer on sender's side>
* <[1] 8-bit number of sender's peer's active path addresses>
* <[...] series of serialized InetAddresses of sender's peer's paths>
*
* This requests that we perform NAT-t introduction between a peer that
* we have and one on the sender's side. The sender furnishes contact
* info for its peer, and we send VERB_RENDEZVOUS to both sides: to ours
* directly and with PROXY_SEND to theirs.
*/
CLUSTER_MESSAGE_PROXY_UNITE = 5,
/**
* Request that a cluster member send a packet to a locally-known peer:
* <[5] ZeroTier address of recipient>
* <[1] packet verb>
* <[2] length of packet payload>
* <[...] packet payload>
*
* This differs from RELAY in that it requests the receiving cluster
* member to actually compose a ZeroTier Packet from itself to the
* provided recipient. RELAY simply says "please forward this blob."
* RELAY is used to implement peer-to-peer relaying with RENDEZVOUS,
* while PROXY_SEND is used to implement proxy sending (which right
* now is only used to send RENDEZVOUS).
*/
CLUSTER_MESSAGE_PROXY_SEND = 6,
/**
* Replicate a network config for a network we belong to:
* <[8] 64-bit network ID>
* <[2] 16-bit length of network config>
* <[...] serialized network config>
*
* This is used by clusters to avoid every member having to query
* for the same netconf for networks all members belong to.
*
* TODO: not implemented yet!
*/
CLUSTER_MESSAGE_NETWORK_CONFIG = 7
};
/**
* Construct a new cluster
*/
Cluster(
const RuntimeEnvironment *renv,
uint16_t id,
const std::vector<InetAddress> &zeroTierPhysicalEndpoints,
int32_t x,
int32_t y,
int32_t z,
void (*sendFunction)(void *,unsigned int,const void *,unsigned int),
void *sendFunctionArg,
int (*addressToLocationFunction)(void *,const struct sockaddr_storage *,int *,int *,int *),
void *addressToLocationFunctionArg);
~Cluster();
/**
* @return This cluster member's ID
*/
inline uint16_t id() const throw() { return _id; }
/**
* Handle an incoming intra-cluster message
*
* @param data Message data
* @param len Message length (max: ZT_CLUSTER_MAX_MESSAGE_LENGTH)
*/
void handleIncomingStateMessage(const void *msg,unsigned int len);
/**
* Broadcast that we have a given peer
*
* This should be done when new peers are first contacted.
*
* @param id Identity of peer
*/
void broadcastHavePeer(const Identity &id);
/**
* Send this packet via another node in this cluster if another node has this peer
*
* This is used in the outgoing packet and relaying logic in Switch to
* relay packets to other cluster members. It isn't PROXY_SEND-- that is
* used internally in Cluster to send responses to peer queries.
*
* @param fromPeerAddress Source peer address (if known, should be NULL for fragments)
* @param toPeerAddress Destination peer address
* @param data Packet or packet fragment data
* @param len Length of packet or fragment
* @param unite If true, also request proxy unite across cluster
*/
void sendViaCluster(const Address &fromPeerAddress,const Address &toPeerAddress,const void *data,unsigned int len,bool unite);
/**
* Send a distributed query to other cluster members
*
* Some queries such as WHOIS or MULTICAST_GATHER need a response from other
* cluster members. Replies (if any) will be sent back to the peer via
* PROXY_SEND across the cluster.
*
* @param pkt Packet to distribute
*/
void sendDistributedQuery(const Packet &pkt);
/**
* Call every ~ZT_CLUSTER_PERIODIC_TASK_PERIOD milliseconds.
*/
void doPeriodicTasks();
/**
* Add a member ID to this cluster
*
* @param memberId Member ID
*/
void addMember(uint16_t memberId);
/**
* Remove a member ID from this cluster
*
* @param memberId Member ID to remove
*/
void removeMember(uint16_t memberId);
/**
* Find a better cluster endpoint for this peer (if any)
*
* @param redirectTo InetAddress to be set to a better endpoint (if there is one)
* @param peerAddress Address of peer to (possibly) redirect
* @param peerPhysicalAddress Physical address of peer's current best path (where packet was most recently received or getBestPath()->address())
* @param offload Always redirect if possible -- can be used to offload peers during shutdown
* @return True if redirectTo was set to a new address, false if redirectTo was not modified
*/
bool findBetterEndpoint(InetAddress &redirectTo,const Address &peerAddress,const InetAddress &peerPhysicalAddress,bool offload);
/**
* Fill out ZT_ClusterStatus structure (from core API)
*
* @param status Reference to structure to hold result (anything there is replaced)
*/
void status(ZT_ClusterStatus &status) const;
private:
void _send(uint16_t memberId,StateMessageType type,const void *msg,unsigned int len);
void _flush(uint16_t memberId);
void _doREMOTE_WHOIS(uint64_t fromMemberId,const Packet &remotep);
void _doREMOTE_MULTICAST_GATHER(uint64_t fromMemberId,const Packet &remotep);
// These are initialized in the constructor and remain immutable ------------
uint16_t _masterSecret[ZT_SHA512_DIGEST_LEN / sizeof(uint16_t)];
unsigned char _key[ZT_PEER_SECRET_KEY_LENGTH];
const RuntimeEnvironment *RR;
_ClusterSendQueue *const _sendQueue;
void (*_sendFunction)(void *,unsigned int,const void *,unsigned int);
void *_sendFunctionArg;
int (*_addressToLocationFunction)(void *,const struct sockaddr_storage *,int *,int *,int *);
void *_addressToLocationFunctionArg;
const int32_t _x;
const int32_t _y;
const int32_t _z;
const uint16_t _id;
const std::vector<InetAddress> _zeroTierPhysicalEndpoints;
// end immutable fields -----------------------------------------------------
struct _Member
{
unsigned char key[ZT_PEER_SECRET_KEY_LENGTH];
uint64_t lastReceivedAliveAnnouncement;
uint64_t lastAnnouncedAliveTo;
uint64_t load;
uint64_t peers;
int32_t x,y,z;
std::vector<InetAddress> zeroTierPhysicalEndpoints;
Buffer<ZT_CLUSTER_MAX_MESSAGE_LENGTH> q;
Mutex lock;
inline void clear()
{
lastReceivedAliveAnnouncement = 0;
lastAnnouncedAliveTo = 0;
load = 0;
peers = 0;
x = 0;
y = 0;
z = 0;
zeroTierPhysicalEndpoints.clear();
q.clear();
}
_Member() { this->clear(); }
~_Member() { Utils::burn(key,sizeof(key)); }
};
_Member *const _members;
std::vector<uint16_t> _memberIds;
Mutex _memberIds_m;
std::map< std::pair<Address,unsigned int>,uint64_t > _remotePeers; // we need ordered behavior and lower_bound here
Mutex _remotePeers_m;
uint64_t _lastFlushed;
uint64_t _lastCleanedRemotePeers;
uint64_t _lastCleanedQueue;
};
} // namespace ZeroTier
#endif // ZT_ENABLE_CLUSTER
#endif