/*
 * 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/>.
 */

#include <algorithm>

#include "Membership.hpp"
#include "RuntimeEnvironment.hpp"
#include "Peer.hpp"
#include "Topology.hpp"
#include "Switch.hpp"
#include "Packet.hpp"
#include "Node.hpp"

#define ZT_CREDENTIAL_PUSH_EVERY (ZT_NETWORK_AUTOCONF_DELAY / 3)

namespace ZeroTier {

Membership::Membership() :
	_lastUpdatedMulticast(0),
	_lastPushedCom(0),
	_comRevocationThreshold(0),
	_revocations(4),
	_remoteTags(4),
	_remoteCaps(4),
	_remoteCoos(4)
{
	resetPushState();
}

void Membership::pushCredentials(const RuntimeEnvironment *RR,void *tPtr,const uint64_t now,const Address &peerAddress,const NetworkConfig &nconf,int localCapabilityIndex,const bool force)
{
	bool sendCom = ( (nconf.com) && ( ((now - _lastPushedCom) >= ZT_CREDENTIAL_PUSH_EVERY) || (force) ) );

	const Capability *sendCap;
	if (localCapabilityIndex >= 0) {
		sendCap = &(nconf.capabilities[localCapabilityIndex]);
		if ( ((now - _localCredLastPushed.cap[localCapabilityIndex]) >= ZT_CREDENTIAL_PUSH_EVERY) || (force) )
			_localCredLastPushed.cap[localCapabilityIndex] = now;
		else sendCap = (const Capability *)0;
	} else sendCap = (const Capability *)0;

	const Tag *sendTags[ZT_MAX_NETWORK_TAGS];
	unsigned int sendTagCount = 0;
	for(unsigned int t=0;t<nconf.tagCount;++t) {
		if ( ((now - _localCredLastPushed.tag[t]) >= ZT_CREDENTIAL_PUSH_EVERY) || (force) ) {
			_localCredLastPushed.tag[t] = now;
			sendTags[sendTagCount++] = &(nconf.tags[t]);
		}
	}

	const CertificateOfOwnership *sendCoos[ZT_MAX_CERTIFICATES_OF_OWNERSHIP];
	unsigned int sendCooCount = 0;
	for(unsigned int c=0;c<nconf.certificateOfOwnershipCount;++c) {
		if ( ((now - _localCredLastPushed.coo[c]) >= ZT_CREDENTIAL_PUSH_EVERY) || (force) ) {
			_localCredLastPushed.coo[c] = now;
			sendCoos[sendCooCount++] = &(nconf.certificatesOfOwnership[c]);
		}
	}

	unsigned int tagPtr = 0;
	unsigned int cooPtr = 0;
	while ((tagPtr < sendTagCount)||(cooPtr < sendCooCount)||(sendCom)||(sendCap)) {
		Packet outp(peerAddress,RR->identity.address(),Packet::VERB_NETWORK_CREDENTIALS);

		if (sendCom) {
			sendCom = false;
			nconf.com.serialize(outp);
			_lastPushedCom = now;
		}
		outp.append((uint8_t)0x00);

		if (sendCap) {
			outp.append((uint16_t)1);
			sendCap->serialize(outp);
			sendCap = (const Capability *)0;
		} else outp.append((uint16_t)0);

		const unsigned int tagCountAt = outp.size();
		outp.addSize(2);
		unsigned int thisPacketTagCount = 0;
		while ((tagPtr < sendTagCount)&&((outp.size() + sizeof(Tag) + 16) < ZT_PROTO_MAX_PACKET_LENGTH)) {
			sendTags[tagPtr++]->serialize(outp);
			++thisPacketTagCount;
		}
		outp.setAt(tagCountAt,(uint16_t)thisPacketTagCount);

		// No revocations, these propagate differently
		outp.append((uint16_t)0);

		const unsigned int cooCountAt = outp.size();
		outp.addSize(2);
		unsigned int thisPacketCooCount = 0;
		while ((cooPtr < sendCooCount)&&((outp.size() + sizeof(CertificateOfOwnership) + 16) < ZT_PROTO_MAX_PACKET_LENGTH)) {
			sendCoos[cooPtr++]->serialize(outp);
			++thisPacketCooCount;
		}
		outp.setAt(cooCountAt,(uint16_t)thisPacketCooCount);

		outp.compress();
		RR->sw->send(tPtr,outp,true);
	}
}

Membership::AddCredentialResult Membership::addCredential(const RuntimeEnvironment *RR,void *tPtr,const NetworkConfig &nconf,const CertificateOfMembership &com)
{
	const uint64_t newts = com.timestamp();
	if (newts <= _comRevocationThreshold) {
		TRACE("addCredential(CertificateOfMembership) for %s on %.16llx REJECTED (revoked)",com.issuedTo().toString().c_str(),com.networkId());
		return ADD_REJECTED;
	}

	const uint64_t oldts = _com.timestamp();
	if (newts < oldts) {
		TRACE("addCredential(CertificateOfMembership) for %s on %.16llx REJECTED (older than current)",com.issuedTo().toString().c_str(),com.networkId());
		return ADD_REJECTED;
	}
	if ((newts == oldts)&&(_com == com)) {
		TRACE("addCredential(CertificateOfMembership) for %s on %.16llx ACCEPTED (redundant)",com.issuedTo().toString().c_str(),com.networkId());
		return ADD_ACCEPTED_REDUNDANT;
	}

	switch(com.verify(RR,tPtr)) {
		default:
			TRACE("addCredential(CertificateOfMembership) for %s on %.16llx REJECTED (invalid signature or object)",com.issuedTo().toString().c_str(),com.networkId());
			return ADD_REJECTED;
		case 0:
			TRACE("addCredential(CertificateOfMembership) for %s on %.16llx ACCEPTED (new)",com.issuedTo().toString().c_str(),com.networkId());
			_com = com;
			return ADD_ACCEPTED_NEW;
		case 1:
			return ADD_DEFERRED_FOR_WHOIS;
	}
}

// Template out addCredential() for many cred types to avoid copypasta
template<typename C>
static Membership::AddCredentialResult _addCredImpl(Hashtable<uint32_t,C> &remoteCreds,const Hashtable<uint64_t,uint64_t> &revocations,const RuntimeEnvironment *RR,void *tPtr,const NetworkConfig &nconf,const C &cred)
{
	C *rc = remoteCreds.get(cred.id());
	if (rc) {
		if (rc->timestamp() >= cred.timestamp()) {
			TRACE("addCredential(type==%d) for %s on %.16llx REJECTED (older than credential we have)",(int)C::credentialType(),cred.issuedTo().toString().c_str(),cred.networkId());
			return Membership::ADD_REJECTED;
		}
		if (*rc == cred) {
			TRACE("addCredential(type==%d) for %s on %.16llx ACCEPTED (redundant)",(int)C::credentialType(),cred.issuedTo().toString().c_str(),cred.networkId());
			return Membership::ADD_ACCEPTED_REDUNDANT;
		}
	}

	const uint64_t *const rt = revocations.get(Membership::credentialKey(C::credentialType(),cred.id()));
	if ((rt)&&(*rt >= cred.timestamp())) {
		TRACE("addCredential(type==%d) for %s on %.16llx REJECTED (timestamp below revocation threshold)",(int)C::credentialType(),cred.issuedTo().toString().c_str(),cred.networkId());
		return Membership::ADD_REJECTED;
	}

	switch(cred.verify(RR,tPtr)) {
		default:
			TRACE("addCredential(type==%d) for %s on %.16llx REJECTED (invalid)",(int)C::credentialType(),cred.issuedTo().toString().c_str(),cred.networkId());
			return Membership::ADD_REJECTED;
		case 0:
			TRACE("addCredential(type==%d) for %s on %.16llx ACCEPTED (new)",(int)C::credentialType(),cred.issuedTo().toString().c_str(),cred.networkId());
			if (!rc)
				rc = &(remoteCreds[cred.id()]);
			*rc = cred;
			return Membership::ADD_ACCEPTED_NEW;
		case 1:
			return Membership::ADD_DEFERRED_FOR_WHOIS;
	}
}

Membership::AddCredentialResult Membership::addCredential(const RuntimeEnvironment *RR,void *tPtr,const NetworkConfig &nconf,const Tag &tag) { return _addCredImpl<Tag>(_remoteTags,_revocations,RR,tPtr,nconf,tag); }
Membership::AddCredentialResult Membership::addCredential(const RuntimeEnvironment *RR,void *tPtr,const NetworkConfig &nconf,const Capability &cap) { return _addCredImpl<Capability>(_remoteCaps,_revocations,RR,tPtr,nconf,cap); }
Membership::AddCredentialResult Membership::addCredential(const RuntimeEnvironment *RR,void *tPtr,const NetworkConfig &nconf,const CertificateOfOwnership &coo) { return _addCredImpl<CertificateOfOwnership>(_remoteCoos,_revocations,RR,tPtr,nconf,coo); }

Membership::AddCredentialResult Membership::addCredential(const RuntimeEnvironment *RR,void *tPtr,const NetworkConfig &nconf,const Revocation &rev)
{
	uint64_t *rt;
	switch(rev.verify(RR,tPtr)) {
		default:
			return ADD_REJECTED;
		case 0: {
			const Credential::Type ct = rev.type();
			switch(ct) {
				case Credential::CREDENTIAL_TYPE_COM:
					if (rev.threshold() > _comRevocationThreshold) {
						_comRevocationThreshold = rev.threshold();
						return ADD_ACCEPTED_NEW;
					}
					return ADD_ACCEPTED_REDUNDANT;
				case Credential::CREDENTIAL_TYPE_CAPABILITY:
				case Credential::CREDENTIAL_TYPE_TAG:
				case Credential::CREDENTIAL_TYPE_COO:
					rt = &(_revocations[credentialKey(ct,rev.credentialId())]);
					if (*rt < rev.threshold()) {
						*rt = rev.threshold();
						return ADD_ACCEPTED_NEW;
					}
					return ADD_ACCEPTED_REDUNDANT;
				default:
					return ADD_REJECTED;
			}
		}
		case 1:
			return ADD_DEFERRED_FOR_WHOIS;
	}
}

void Membership::clean(const uint64_t now,const NetworkConfig &nconf)
{
	_cleanCredImpl<Tag>(nconf,_remoteTags);
	_cleanCredImpl<Capability>(nconf,_remoteCaps);
	_cleanCredImpl<CertificateOfOwnership>(nconf,_remoteCoos);
}

} // namespace ZeroTier