DDS-SECURITY 1.2 RTF Avatar
  1. OMG Issue

DDSSEC12 — Modify Security's QoS changes for compatibility with RTPS

  • Key: DDSSEC12-37
  • Status: open  
  • Source: OCI ( Adam Mitz)
  • Summary:

    Section 7.2.5 changes QoS in ways that break RTPS compatibility, however minor modifications can fix this.

    Because the mapping for PropertyQosPolicy in Table 10 (is this an implied entry in Table 12 as well?) conflicts with RTPS's definition of PID 0x59, the Binary Property values may not be sent on the wire. Note that RTPS has no concept of appendable extensibility, and requires backwards compatibility for all 2.x versions.

    We can represent this restriction on PropertyQosPolicy in IDL4:

    @extensibility(FINAL)
    struct PropertyQosPolicy {
      PropertySeq value;
    
      @non-serialized
      BinaryPropertySeq binary_value;
    };
    

    The practical effect of this change is that any BinaryProperty entry with propagate == TRUE is not actually propagated inside PropertyQosPolicy. However a search through the specification indicates that there is no requirement for this, at least for built-in plugins. Any other plugins are necessarily vendor specific so those are not necessarily restricted from using an appendable policy, as long as they are aware of the compatibility issues (for allow_unauthenticated_participants == TRUE).

    Also, for consistency the Tag and DataTags structs could be made @extensibility(FINAL). This is not as important since only Security-aware implementations will know about DataTagQosPolicy.

  • Reported: DDS-SECURITY 1.1b1 — Mon, 19 Feb 2018 23:37 GMT
  • Updated: Mon, 19 Feb 2018 23:39 GMT