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offbynull / portmapper

Java library that maps ports on NAT-enabled routers (supported protocols: UPnP-IGD/NAT-PMP/PCP).
Apache License 2.0
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PCPv1 support #3

Closed offbynull closed 8 years ago

offbynull commented 9 years ago

Add support for PCPv1

offbynull commented 9 years ago

Re-investigate what PCP standards need to be implemented. This standard is a bit of a nightmare. http://tools.ietf.org/wg/pcp/ -- how much of this is relevant to client writers is unknown at this point.

offbynull commented 8 years ago

Not going to support PCPv1, because there is no hard PCPv1 spec. Added the following comments to the source code:

    // RFC drafts 26 to 29 use version number 2. Prior drafts use version 1. The version number change was introduced to avoid communication
    // issues between clients and servers that implemented draft-versions of the spec. The RFC draft changelog notes this change as ...
    // "Bump version number from 1 to 2, to accommodate pre-RFC PCP client implementations without needing a heuristic."
    //
    // Prior to version 2, the RFC drafts are all over the place. The communication protocol (packet structures / constants / etc...) change
    // non-trivially between drafts. For example, changes between draft 24 and 25 include the addition of nonces for MAP/PEER and a maximum
    // UDP packet size of 1024 (as opposed to 1100 in the final RFC).
    //
    // As such, it would be impossible to support all variations of version 1. Chances are that home-grade routers that supported some draft
    // version of PCP version 1 also supported other protocols capable of IPv6 support (such as UPNP-IGDv2) or have subsequently been
    // updated to support PCP version 2 via a firmware update.
    //
    // Given all this, we're only going to support PCP_VERSION 2.