Flesh out membership certificate with signature, better serialize/deserialize, and rename parameter to qualifier to make better conceptual sense.

node/Network.hpp

@@ -51,6 +51,7 @@
 #include "Identity.hpp"
 #include "InetAddress.hpp"
 #include "BandwidthAccount.hpp"
+#include "C25519.hpp"
 
 namespace ZeroTier {
 
@@ -86,37 +87,71 @@ public:
 	/**
 	 * Certificate of network membership
 	 *
-	 * The COM consists of a series of three-element 64-bit tuples. These values
-	 * are 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 for a given
-	 * type of parameter. ID 0 is reserved for the always-present timestamp
-	 * parameter. The value is parameter-specific. The maximum delta is the
-	 * maximum difference that is permitted between two values for determining
-	 * whether a certificate permits two peers to speak to one another. A value
-	 * of zero indicates that the values must equal.
+	 * The COM contains a sorted set of three-element tuples called qualifiers.
+	 * These contain an id, a value, and a maximum delta.
 	 *
-	 * Certificates of membership must be signed by the netconf master for the
-	 * network in question. This permits members to verify these certs against
-	 * the netconf master's public key before testing them.
+	 * The ID is arbitrary and should be assigned using a scheme that makes
+	 * every ID globally unique. ID 0 is reserved for the always-present
+	 * validity timestamp and range, and ID 1 is reserved for the always-present
+	 * network ID. IDs less than 65536 are reserved for future global
+	 * assignment.
+	 *
+	 * 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:
-		CertificateOfMembership() throw() {}
+		/**
+		 * 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 COM IDs
+		 *
+		 * IDs below 65536 should be considered reserved for future global
+		 * assignment here.
+		 */
+		enum ReservedIds
+		{
+			COM_RESERVED_ID_TIMESTAMP = 0, // timestamp, max delta defines cert life
+			COM_RESERVED_ID_NETWORK_ID = 1 // network ID, max delta always 0
+		};
+
+		CertificateOfMembership() {}
 		CertificateOfMembership(const char *s) { fromString(s); }
 		CertificateOfMembership(const std::string &s) { fromString(s.c_str()); }
 
 		/**
-		 * Add a paramter to this certificate
+		 * Add or update a qualifier in this certificate
 		 *
-		 * @param id Parameter ID
-		 * @param value Parameter value
-		 * @param maxDelta Parameter maximum difference with others
+		 * 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 addParameter(uint64_t id,uint64_t value,uint64_t maxDelta);
+		void setQualifier(uint64_t id,uint64_t value,uint64_t maxDelta);
 
 		/**
-		 * @return Hex-serialized representation of this certificate (minus signature)
+		 * @return String-serialized representation of this certificate
 		 */
 		std::string toString() const;
 
@@ -138,36 +173,69 @@ public:
 		 * 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 compare(const CertificateOfMembership &other) const
+		bool agreesWith(const CertificateOfMembership &other) const
 			throw();
 
-	private:
-		struct _Parameter
+		/**
+		 * 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()
 		{
-			_Parameter() throw() {}
-			_Parameter(uint64_t i,uint64_t v,uint64_t m) throw() :
+			return (_signedBy);
+		}
+
+		/**
+		 * @return Address that signed this certificate or null address if none
+		 */
+		inline const Address &signedBy() const
+			throw()
+		{
+			return _signedBy;
+		}
+
+	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
 		};
 
-		// Used with std::sort to ensure that _params are sorted
-		struct _SortByIdComparison
-		{
-			inline bool operator()(const _Parameter &a,const _Parameter &b) const
-				throw()
-			{
-				return (a.id < b.id);
-			}
-		};
-
-		std::vector<_Parameter> _params;
+		std::vector<_Qualifier> _qualifiers; // sorted by id and unique
+		Address _signedBy;
+		C25519::Signature _signature;
 	};
 
 	/**