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draft
See also HowToEnableIpvSix .
The Rules
- Do not write code to create or parse sinful strings. Sinful strings are now weird and complex beasts and you will almost certainly miss important edge cases. Use the existing interfaces. You probably want condor_sockaddr::to_sinful or condor_sockaddr::from_sinful.
- Do not use sockaddr_in or sockaddr_in6. condor_sockaddr exists specifically to shield you from needing to worry about those.
The Big Picture
condor_sockaddr
The data structure holding information about a IP address/port pair is condor_sockaddr, which handles juggling sockaddr_in and sockaddr_in6. You shouldn't worry if a given address is IPv6 or IPv4, just use the condor_sockaddr opaquely. If you need a textual but still opaque representation, use condor_sockaddr::to_sinful and condor_sockaddr::from_sinful to create and parse sinful strings. Sinful string are human readable and thus appropriate to use in log messages.
IPv6 addresses require a scope id, identifying which network interface to use. This solves the problem of a single machine being part of two or more private ("link local") networks using the same address space. However, it just creates a new problem: if all you have is an IP address, how do you know which interface to use. The answer: we have no idea. Some tools allow the user to specify the scope ID in a variety of inconsistent ways. This is why NETWORK_INTERFACE is required for IPv6; we use the NETWORK_INTERFACE to identify the scope ID.
condor_netaddr
condor_netaddr exists to encapsulate the idea of a subset. It's built on top of condor_sockaddr, adding a count for how many bits to mask off. At the moment it's only being used to validate that a subset string can be parsed, but should eventually be used in any situation where Condor is checking that a given address is within a given subset (ie security).