Subject: Re: getipnodebyname() and numeric address string arguments with various non-zero flags

From: [email-masked]
Date: Fri, 9 Jul 1999 08:40:35 -0400

First, thanks for your response.  I'm sorry for the delay in getting back to
you.

>I think your asking for the counter to what we did describe too?

I guess so.  The paragraph after "The two simple cases are:" seemed to rule out
checking the flags when the type of numeric address string matched the af
parameter.

Of course, I'm not suggesting a updated RFC and don't know where any sort of
clarifications should live anyway.  So the purpose of the following comments are
for me to better understand the requirements and for other naive readers like
myself perusing this list to better understand them as well.

I think the sentence

"The two simple cases are: When name is a dotted-decimal IPv4 address and af
equals AF_INET, or when name is an IPv6 hex address and af equals AF_INET6."

should be replaced by

"The two simple cases are: When name is a dotted-decimal IPv4 address and af
equals AF_INET, or when name is an IPv6 hex address and af equals AF_INET6, and
either the AI_ADDRCONFIG flag is not specified or a source address is configured
for the specified af."

In addition, the following paragraph should be added:

It is an error when name is a dotted-decimal IPv4 address and af equals AF_INET
and the AI_ADDRCONFIG flag is specified and there is no IPv4 source address
configured.  It is an error when name is a IPv6 hex address but not an
IPv4-mapped IPv6 address and af equals AF_INET6 and the AI_ADDRCONFIG flag is
specified and there is no IPv6 source address configured.

>But link-local addresses are not kept in the DNS at this time.

I'm afraid I don't follow.  Was anything I said specific to link-local addresses
without me knowing it?

Thanks and best wishes,

Jeff Trawick, [email-masked]
IBM SecureWay (nee' eNetwork) Software Tips:
->http://www2.software.ibm.com/eNetwork/Tips.nsf/Tips?OpenView&Count=500
OS/390 UNIX - Frequently Asked Questions:
->http://www.s390.ibm.com/oe/bpxqarc.html

Jim Bound <[email-masked]> on 06/28/99 02:24:36 PM

To:   Jeff Trawick/Raleigh/IBM@IBMUS
cc:   [email-masked]
Subject:  Re: getipnodebyname() and numeric address string arguments with
      various non-zero flags

>>From RFC 2553, I gather that it makes no difference what is passed for the
flags
>parameter on getipnodebyname() when the type of the numeric address string
>matches the address family parameter.  Right?

No.  AI_V4MAPPED, AI_ADDRCONFIG, and AI_ALL still can be used.

>So getipnodebyname("FE80::1000:whatever",AF_INET6,AI_DEFAULT,&error_num) on a
>system that doesn't have a local IPv6 interface will succeed, but the
>application won't be able to use the resulting address.  Right?

No.   An error should be returned because AF_INET6 is specified and no
IPv6 interface exists.

AI_DEFAULT == (AI_V4MAPPED | AI_ADDRCONFIG)

So one could get back a mapped address.

But link-local addresses are not kept in the DNS at this time.

>If this is correct, perhaps future documentation should be more clear about
>getipnodebyname() ignoring flags for this scenario?

I think your asking for the counter to what we did describe too?

/jim

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