enum ErrorCode
{
    ERR_MISC = 0, // Unspecific error
    ERR_DATA = 1, // Malformed data
    ERR_CONF = 2, // Misconfiguration error
    ERR_AUTH = 3, // Authentication failure
    ERR_LOAD = 4  // System overloaded
};

struct Error
{
    ErrorCode code;
    string msg<100>;
};

struct AuthCert
{
    Curve25519Public pubkey;
    uint64 expiration;
    Signature sig;
};

struct Hello
{
    uint32 ledgerVersion;
    uint32 overlayVersion;
    uint32 overlayMinVersion;
    Hash networkID;
    string versionStr<100>;
    int listeningPort;
    NodeID peerID;
    AuthCert cert;
    uint256 nonce;
};

struct Auth
{
    // Empty message, just to confirm
    // establishment of MAC keys.
    int unused;
};

enum IPAddrType
{
    IPv4 = 0,
    IPv6 = 1
};

union PeerAddressIp switch (IPAddrType type)
{
case IPv4:
    opaque ipv4[4];
case IPv6:
    opaque ipv6[16];
};

struct PeerAddress
{
    PeerAddressIp ip;
    uint32 port;
    uint32 numFailures;
};

enum MessageType
{
    ERROR_MSG = 0,
    AUTH = 2,
    DONT_HAVE = 3,

    GET_PEERS = 4, // gets a list of peers this guy knows about
    PEERS = 5,

    GET_TX_SET = 6, // gets a particular txset by hash
    TX_SET = 7,

    TRANSACTION = 8, // pass on a tx you have heard about

    // SCP
    GET_SCP_QUORUMSET = 9,
    SCP_QUORUMSET = 10,
    SCP_MESSAGE = 11,
    GET_SCP_STATE = 12,

    // new messages
    HELLO = 13
};

struct DontHave
{
    MessageType type;
    uint256 reqHash;
};

union StellarMessage switch (MessageType type)
{
case ERROR_MSG:
    Error error;
case HELLO:
    Hello hello;
case AUTH:
    Auth auth;
case DONT_HAVE:
    DontHave dontHave;
case GET_PEERS:
    void;
case PEERS:
    PeerAddress peers<100>;

case GET_TX_SET:
    uint256 txSetHash;
case TX_SET:
    TransactionSet txSet;

case TRANSACTION:
    TransactionEnvelope transaction;

// SCP
case GET_SCP_QUORUMSET:
    uint256 qSetHash;
case SCP_QUORUMSET:
    SCPQuorumSet qSet;
case SCP_MESSAGE:
    SCPEnvelope envelope;
case GET_SCP_STATE:
    uint32 getSCPLedgerSeq; // ledger seq requested ; if 0, requests the latest
};

struct AuthenticatedMessageV0
{
    uint64 sequence;
    StellarMessage message;
    HmacSha256Mac mac;
};

union AuthenticatedMessage switch (int v)
{
case 0:
    AuthenticatedMessageV0 v0;
};