Re: ipv6 addresses in pcap_addr

[Chris Morgan <chmorgan () gmail com>]

On Thu, Jan 22, 2009 at 7:59 PM, Guy Harris <guy () alum mit edu> wrote:
> On Jan 22, 2009, at 4:05 PM, Chris Morgan wrote:
>
> > Hello.
> >
> > I wasn't sure if this question was answered anywhere, I've searched
> > via google and looked on the mailing lists but haven't seen any
> > answers.
> >
> > How does one get a ipv6 address from the sockaddr struct pointed to by
> > pcap_addr?
>
> Welcome to the wonderful world of C, the programming language that combines
> the power of assembly language with the convenience of assembly language....
>
> "struct sockaddr" is a sort of place-holder structure.  There are few, if
> any, real "struct sockaddr" structures out there; instead, there are "struct
> sockaddr_XXX" structures, for various values of XXX.  "struct sockaddr" is
> an abstraction that covers all of them; all "struct sockaddr_XXX" structures
> begin with members that are the same as the non-"sa_data" members of "struct
> sockaddr", and with the same structure offsets as those members, and have,
> following that, the address-type-specific data, starting at the same offset
> as the "sa_data" member of "struct sockaddr", but not necessarily having the
> same *length* as the "sa_data" member of that structure - it could be longer
> (and possibly shorter).

Doh. I know exactly what you mean now. I didn't notice anything on the
pcap man page about that, probably because its something documented
elsewhere. I had no idea that the sockaddr structure was used this
way. Thank you for the tip and sorry for causing you to write such an
extensive post, I appreciate your help.

Chris
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