I wrote up a basic proposal for the new msgr2 protocol: http://pad.ceph.com/p/msgr2 It is pretty similar to the current protocol, with a few key changes: 1. The initial banner has a version number for protocl features supported and required. This will allow optional behavior later. The current protocol doesn't allow this (the banner string is fixed and has to match verbatim). 2. The auth handshake is a low-level msgr exchange now. This more or less matches the MAuth and MAuthReply exchange with the mon. Also, the authenticator/ticket presentation for established clients can be sent here as part of this exchange, instead of as part of the msg_connect and msg_connect_reply exchnage. 3. The identification of peers during connect is moved to the TAG_IDENT stage. This way it could happen after authentication and/or encryption, if we like. (Not sure it matters.) 4. Signatures are a separate message now that follows the previous message. If a message doesn't have a signature that follows, it is dropped. Once authenticated we can sign all the other handshake exchanges (TAG_IDENT, etc.) as well as the messages themselves. 5. The reconnect behavior for stateful connections is a separate exchange. This keeps the stateless connections free of clutter. 6. A few changes in the auth_none and cephx integratoin will be needed. For example, all the current stubs assume that authentication happens over MAuth message and authorization happens in an authorizer blob in ceph_msg_connect. Now both are part of TAG_AUTH_REQUEST, so we'll need to multiplex the cephx message blobs. Also, because the IDENT exchanges happens later, we may need to pass additional info in the auth handshake messages (like the peer type, or whatever else is needed). 7. Lots of messages can go either way, and I tried ot avoid a strict request/response model so that things could be pipelined, and we'd spend a minimal amount of time waiting for a response from the other end. For example, C: initiates connection S: accepts connection -> banner -> TAG_AUTH_METHODS C: -> banner -> TAG_AUTH_SET_METHOD -> TAG_AUTH_AUTH_REQUEST S: -> TAG_AUTH_REPLY C: -> TAG_ENCRYPT_BEGIN -> TAG_IDENT -> TAG_SIGNATURE S: -> TAG_ENCRYPT_BEGIN -> TAG_IDENT -> TAG_SIGNATURE C: -> TAG_START -> TAG_SIGNATURE -> TAG_MSG -> TAG_SIGNATURE ... S: -> TAG_MSG -> TAG_SIGNATURE ... Comments, please! The exhange is a bit less structured as far as who sends what message, with the idea that we could pipeline a lot of it, but it may end up being too ambiguous. Let me know what you think... sage -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
