diff options
Diffstat (limited to 'node/Packet.hpp')
| -rw-r--r-- | node/Packet.hpp | 38 |
1 files changed, 29 insertions, 9 deletions
diff --git a/node/Packet.hpp b/node/Packet.hpp index 6482356a..d5817708 100644 --- a/node/Packet.hpp +++ b/node/Packet.hpp @@ -59,15 +59,17 @@ * + Otherwise backward compatible with protocol v4 * 6 - 1.1.5 ... 1.1.10 * + Network configuration format revisions including binary values - * 7 - 1.1.10 -- 1.2.0 + * 7 - 1.1.10 ... 1.1.17 * + Introduce trusted paths for local SDN use - * 8 - 1.2.0 -- CURRENT + * 8 - 1.1.17 ... 1.2.0 * + Multipart network configurations for large network configs * + Tags and Capabilities * + Inline push of CertificateOfMembership deprecated * + Certificates of representation for federation and mesh + * 9 - 1.2.0 ... CURRENT + * + In-band encoding of packet counter for link quality measurement */ -#define ZT_PROTO_VERSION 8 +#define ZT_PROTO_VERSION 9 /** * Minimum supported protocol version @@ -351,7 +353,7 @@ namespace ZeroTier { * ZeroTier packet * * Packet format: - * <[8] 64-bit random packet ID and crypto initialization vector> + * <[8] 64-bit packet ID / crypto IV / packet counter> * <[5] destination ZT address> * <[5] source ZT address> * <[1] flags/cipher/hops> @@ -362,6 +364,14 @@ namespace ZeroTier { * * Packets smaller than 28 bytes are invalid and silently discarded. * + * The 64-bit packet ID is a strongly random value used as a crypto IV. + * Its least significant 3 bits are also used as a monotonically increasing + * (and looping) counter for sending packets to a particular recipient. This + * can be used for link quality monitoring and reporting and has no crypto + * impact as it does not increase the likelihood of an IV collision. (The + * crypto we use is not sensitive to the nature of the IV, only that it does + * not repeat.) + * * The flags/cipher/hops bit field is: FFCCCHHH where C is a 3-bit cipher * selection allowing up to 7 cipher suites, F is outside-envelope flags, * and H is hop count. @@ -1102,10 +1112,8 @@ public: }; #ifdef ZT_TRACE - static const char *verbString(Verb v) - throw(); - static const char *errorString(ErrorCode e) - throw(); + static const char *verbString(Verb v); + static const char *errorString(ErrorCode e); #endif template<unsigned int C2> @@ -1303,11 +1311,22 @@ public: /** * Get this packet's unique ID (the IV field interpreted as uint64_t) * + * Note that the least significant 3 bits of this ID will change when armor() + * is called to armor the packet for transport. This is because armor() will + * mask the last 3 bits against the send counter for QoS monitoring use prior + * to actually using the IV to encrypt and MAC the packet. Be aware of this + * when grabbing the packetId of a new packet prior to armor/send. + * * @return Packet ID */ inline uint64_t packetId() const { return at<uint64_t>(ZT_PACKET_IDX_IV); } /** + * @return Value of link quality counter extracted from this packet's ID, range 0 to 7 (3 bits) + */ + inline unsigned int linkQualityCounter() const { return (unsigned int)(reinterpret_cast<const uint8_t *>(data())[7] & 7); } + + /** * Set packet verb * * This also has the side-effect of clearing any verb flags, such as @@ -1337,8 +1356,9 @@ public: * * @param key 32-byte key * @param encryptPayload If true, encrypt packet payload, else just MAC + * @param counter Packet send counter for destination peer -- only least significant 3 bits are used */ - void armor(const void *key,bool encryptPayload); + void armor(const void *key,bool encryptPayload,unsigned int counter); /** * Verify and (if encrypted) decrypt packet |