[jira] [Commented] (TS-756) Clean out unused carp from DNS resolver structure and code.

["Alan M. Carroll (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/TS-756?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13027152#comment-13027152 ] 

Alan M. Carroll commented on TS-756:
------------------------------------

Original email on the dev list for this bug.


I'm working on ink_resolver.h and ink_res_init.cc with regard to use sockaddr_storage and have come across what I find rather odd bits of code.

1) What is the sort_list about? It is loaded during initialization but apparently never referenced again, and the #define that enables it isn't set by configure.ac. Most significantly, it's not documented. So I am removing it entirely.

2) The nssocks array in __ink_res_state also seems vestigal but with the added element of risk. I can find no place it is initialized yet when the state is destroyed if any of the values are not -1 that file descriptor is closed. The effect would seem to be random closing file descriptors. I plan to remove that as well.

3) Is there some reason the __ink_res_state should be 512 bytes? It seems that the current structure is much larger than that. If that's not a requirement, why is the _ext struct in __ink_res_state in a padded union?

4) I don't see the point of the __ink_res_state_ext structure. It seems like it is vestigal from before the existence of ink_res_sockaddr_union. But that's now used in __ink_res_state (and I will be replacing it with sockaddr_storage anyway). I can find no use of the nsuffix or nsuffix2 members, which leaves the struct just another array of ink_res_sockaddr_union structs. I plan to simply discard the entire structure and use the nsaddr_list in __ink_res_state. This leaves the _ext struct with just two members which I think should be moved out to the main struct.

P.S. All that apparent concern about alignment, but there's a u_short id right in the middle of the struct.


> Clean out unused carp from DNS resolver structure and code.
> -----------------------------------------------------------
>
>                 Key: TS-756
>                 URL: https://issues.apache.org/jira/browse/TS-756
>             Project: Traffic Server
>          Issue Type: Improvement
>          Components: DNS
>    Affects Versions: 2.1.7
>            Reporter: Alan M. Carroll
>            Assignee: Alan M. Carroll
>            Priority: Minor
>             Fix For: 2.1.9
>
>         Attachments: ts-756.patch
>
>
> The target structure is __ink_res_state in lib/ts/ink_resolver.h. The items to be removed are
> IPv6 nibble support. This flag and associated values are never checked anywhere else in the codebase.
> The nssocks array. This is a potential bug as it is never initialized but is used to close file descriptors.
> Sort list support which is also never used.
> The point of this is to avoid working on IPv6 support for things that aren't used.

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