/*
* ZeroTier One - Global Peer to Peer Ethernet
* Copyright (C) 2011-2014 ZeroTier Networks LLC
*
* 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/>.
*
* --
*
* ZeroTier may be used and distributed under the terms of the GPLv3, which
* are available at: http://www.gnu.org/licenses/gpl-3.0.html
*
* If you would like to embed ZeroTier into a commercial application or
* redistribute it in a modified binary form, please contact ZeroTier Networks
* LLC. Start here: http://www.zerotier.com/
*/
#ifndef ZT_CERTIFICATEOFMEMBERSHIP_HPP
#define ZT_CERTIFICATEOFMEMBERSHIP_HPP
#include <stdint.h>
#include <string.h>
#include <string>
#include <vector>
#include <stdexcept>
#include "Constants.hpp"
#include "Buffer.hpp"
#include "Address.hpp"
#include "C25519.hpp"
#include "Identity.hpp"
namespace ZeroTier {
/**
* Certificate of network membership
*
* The COM contains a sorted set of three-element tuples called qualifiers.
* These contain an id, a value, and a maximum delta.
*
* The ID is arbitrary and should be assigned using a scheme that makes
* every ID globally unique. IDs beneath 65536 are reserved for global
* assignment by ZeroTier Networks.
*
* The value's meaning is ID-specific and isn't important here. What's
* important is the value and the third member of the tuple: the maximum
* delta. The maximum delta is the maximum difference permitted between
* values for a given ID between certificates for the two certificates to
* themselves agree.
*
* Network membership is checked by checking whether a peer's certificate
* agrees with your own. The timestamp provides the fundamental criterion--
* each member of a private network must constantly obtain new certificates
* often enough to stay within the max delta for this qualifier. But other
* criteria could be added in the future for very special behaviors, things
* like latitude and longitude for instance.
*/
class CertificateOfMembership
{
public:
/**
* Certificate type codes, used in serialization
*
* Only one so far, and only one hopefully there shall be for quite some
* time.
*/
enum Type
{
COM_UINT64_ED25519 = 1 // tuples of unsigned 64's signed with Ed25519
};
/**
* Reserved qualifier IDs
*
* IDs below 65536 should be considered reserved for future global
* assignment here.
*
* Addition of new required fields requires that code in hasRequiredFields
* be updated as well.
*/
enum ReservedId
{
/**
* Timestamp of certificate issue in milliseconds since epoch
*
* maxDelta here defines certificate lifetime, and certs are lazily
* pushed to other peers on a net with a frequency of 1/2 this time.
*/
COM_RESERVED_ID_TIMESTAMP = 0,
/**
* Network ID for which certificate was issued
*
* maxDelta here is zero, since this must match.
*/
COM_RESERVED_ID_NETWORK_ID = 1,
/**
* ZeroTier address to whom certificate was issued
*
* maxDelta will be 0xffffffffffffffff here since it's permitted to differ
* from peers obviously.
*/
COM_RESERVED_ID_ISSUED_TO = 2
};
/**
* Create an empty certificate
*/
CertificateOfMembership() { memset(_signature.data,0,_signature.size()); }
/**
* Create from required fields common to all networks
*
* @param timestamp Timestamp of cert
* @param timestampMaxDelta Maximum variation between timestamps on this net
* @param nwid Network ID
* @param issuedTo Certificate recipient
*/
CertificateOfMembership(uint64_t timestamp,uint64_t timestampMaxDelta,uint64_t nwid,const Address &issuedTo)
{
_qualifiers.push_back(_Qualifier(COM_RESERVED_ID_TIMESTAMP,timestamp,timestampMaxDelta));
_qualifiers.push_back(_Qualifier(COM_RESERVED_ID_NETWORK_ID,nwid,0));
_qualifiers.push_back(_Qualifier(COM_RESERVED_ID_ISSUED_TO,issuedTo.toInt(),0xffffffffffffffffULL));
memset(_signature.data,0,_signature.size());
}
/**
* Create from string-serialized data
*
* @param s String-serialized COM
*/
CertificateOfMembership(const char *s) { fromString(s); }
/**
* Create from string-serialized data
*
* @param s String-serialized COM
*/
CertificateOfMembership(const std::string &s) { fromString(s.c_str()); }
/**
* Create from binary-serialized COM in buffer
*
* @param b Buffer to deserialize from
* @param startAt Position to start in buffer
*/
template<unsigned int C>
CertificateOfMembership(const Buffer<C> &b,unsigned int startAt = 0)
throw(std::out_of_range,std::invalid_argument)
{
deserialize(b,startAt);
}
/**
* @return True if there's something here
*/
inline operator bool() const
throw()
{
return (_qualifiers.size() != 0);
}
/**
* Check for presence of all required fields common to all networks
*
* @return True if all required fields are present
*/
inline bool hasRequiredFields() const
throw()
{
if (_qualifiers.size() < 3)
return false;
if (_qualifiers[0].id != COM_RESERVED_ID_TIMESTAMP)
return false;
if (_qualifiers[1].id != COM_RESERVED_ID_NETWORK_ID)
return false;
if (_qualifiers[2].id != COM_RESERVED_ID_ISSUED_TO)
return false;
return true;
}
/**
* @return Maximum delta for mandatory timestamp field or 0 if field missing
*/
inline uint64_t timestampMaxDelta() const
throw()
{
for(std::vector<_Qualifier>::const_iterator q(_qualifiers.begin());q!=_qualifiers.end();++q) {
if (q->id == COM_RESERVED_ID_TIMESTAMP)
return q->maxDelta;
}
return 0ULL;
}
/**
* @return Timestamp for this cert in ms since epoch (according to netconf's clock)
*/
inline uint64_t timestamp() const
throw()
{
for(std::vector<_Qualifier>::const_iterator q(_qualifiers.begin());q!=_qualifiers.end();++q) {
if (q->id == COM_RESERVED_ID_TIMESTAMP)
return q->value;
}
return 0ULL;
}
/**
* @return Address to which this cert was issued
*/
inline Address issuedTo() const
throw()
{
for(std::vector<_Qualifier>::const_iterator q(_qualifiers.begin());q!=_qualifiers.end();++q) {
if (q->id == COM_RESERVED_ID_ISSUED_TO)
return Address(q->value);
}
return Address();
}
/**
* @return Network ID for which this cert was issued
*/
inline uint64_t networkId() const
throw()
{
for(std::vector<_Qualifier>::const_iterator q(_qualifiers.begin());q!=_qualifiers.end();++q) {
if (q->id == COM_RESERVED_ID_NETWORK_ID)
return q->value;
}
return 0ULL;
}
/**
* Add or update a qualifier in this certificate
*
* Any signature is invalidated and signedBy is set to null.
*
* @param id Qualifier ID
* @param value Qualifier value
* @param maxDelta Qualifier maximum allowed difference (absolute value of difference)
*/
void setQualifier(uint64_t id,uint64_t value,uint64_t maxDelta);
inline void setQualifier(ReservedId id,uint64_t value,uint64_t maxDelta) { setQualifier((uint64_t)id,value,maxDelta); }
/**
* @return String-serialized representation of this certificate
*/
std::string toString() const;
/**
* Set this certificate equal to the hex-serialized string
*
* Invalid strings will result in invalid or undefined certificate
* contents. These will subsequently fail validation and comparison.
* Empty strings will result in an empty certificate.
*
* @param s String to deserialize
*/
void fromString(const char *s);
inline void fromString(const std::string &s) { fromString(s.c_str()); }
/**
* Compare two certificates for parameter agreement
*
* This compares this certificate with the other and returns true if all
* paramters in this cert are present in the other and if they agree to
* within this cert's max delta value for each given parameter.
*
* Tuples present in other but not in this cert are ignored, but any
* tuples present in this cert but not in other result in 'false'.
*
* @param other Cert to compare with
* @return True if certs agree and 'other' may be communicated with
*/
bool agreesWith(const CertificateOfMembership &other) const
throw();
/**
* Sign this certificate
*
* @param with Identity to sign with, must include private key
* @return True if signature was successful
*/
bool sign(const Identity &with);
/**
* Verify certificate against an identity
*
* @param id Identity to verify against
* @return True if certificate is signed by this identity and verification was successful
*/
bool verify(const Identity &id) const;
/**
* @return True if signed
*/
inline bool isSigned() const throw() { return (_signedBy); }
/**
* @return Address that signed this certificate or null address if none
*/
inline const Address &signedBy() const throw() { return _signedBy; }
template<unsigned int C>
inline void serialize(Buffer<C> &b) const
throw(std::out_of_range)
{
b.append((unsigned char)COM_UINT64_ED25519);
b.append((uint16_t)_qualifiers.size());
for(std::vector<_Qualifier>::const_iterator q(_qualifiers.begin());q!=_qualifiers.end();++q) {
b.append(q->id);
b.append(q->value);
b.append(q->maxDelta);
}
_signedBy.appendTo(b);
if (_signedBy)
b.append(_signature.data,(unsigned int)_signature.size());
}
template<unsigned int C>
inline unsigned int deserialize(const Buffer<C> &b,unsigned int startAt = 0)
throw(std::out_of_range,std::invalid_argument)
{
unsigned int p = startAt;
_qualifiers.clear();
_signedBy.zero();
if (b[p++] != COM_UINT64_ED25519)
throw std::invalid_argument("unknown certificate of membership type");
unsigned int numq = b.template at<uint16_t>(p); p += sizeof(uint16_t);
uint64_t lastId = 0;
for(unsigned int i=0;i<numq;++i) {
uint64_t tmp = b.template at<uint64_t>(p);
if (tmp < lastId)
throw std::invalid_argument("certificate qualifiers are not sorted");
else lastId = tmp;
_qualifiers.push_back(_Qualifier(
tmp,
b.template at<uint64_t>(p + 8),
b.template at<uint64_t>(p + 16)
));
p += 24;
}
_signedBy.setTo(b.field(p,ZT_ADDRESS_LENGTH),ZT_ADDRESS_LENGTH);
p += ZT_ADDRESS_LENGTH;
if (_signedBy) {
memcpy(_signature.data,b.field(p,(unsigned int)_signature.size()),_signature.size());
p += (unsigned int)_signature.size();
}
return (p - startAt);
}
inline bool operator==(const CertificateOfMembership &c) const
throw()
{
if (_signedBy != c._signedBy)
return false;
// We have to compare in depth manually since == only compares id
if (_qualifiers.size() != c._qualifiers.size())
return false;
for(unsigned long i=0;i<_qualifiers.size();++i) {
const _Qualifier &a = _qualifiers[i];
const _Qualifier &b = c._qualifiers[i];
if ((a.id != b.id)||(a.value != b.value)||(a.maxDelta != b.maxDelta))
return false;
}
return (_signature == c._signature);
}
inline bool operator!=(const CertificateOfMembership &c) const throw() { return (!(*this == c)); }
private:
struct _Qualifier
{
_Qualifier() throw() {}
_Qualifier(uint64_t i,uint64_t v,uint64_t m) throw() :
id(i),
value(v),
maxDelta(m) {}
uint64_t id;
uint64_t value;
uint64_t maxDelta;
inline bool operator==(const _Qualifier &q) const throw() { return (id == q.id); } // for unique
inline bool operator<(const _Qualifier &q) const throw() { return (id < q.id); } // for sort
};
Address _signedBy;
std::vector<_Qualifier> _qualifiers; // sorted by id and unique
C25519::Signature _signature;
};
} // namespace ZeroTier
#endif