Re: [Exim] Exim 4.03 is available

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Author: Philip Hazel
Date:  
To: Arkadiusz Miskiewicz
CC: exim-users
New-Topics: Re: [Exim] getipnodebyaddr was: Exim 4.03 is available
Subject: Re: [Exim] Exim 4.03 is available
On 16 Apr 2002, Arkadiusz Miskiewicz wrote:

> This
>
> +22. Arranged to use getipnodebyaddr() instead of gethostbyaddr() in systems
> +    with IPv6 support that have this function, because gethostbyaddr() doesn't
> +    work for IPv6 addresses on all systems (it does on some).

>
> --- exim-4.02/OS/os.h-Linux     Mon Mar 25 12:09:42 2002
> +++ exim-4.03/OS/os.h-Linux     Tue Apr 16 12:40:58 2002
> @@ -11,6 +11,9 @@
>  #define F_FREESP     O_TRUNC
>  typedef struct flock flock_t;

>
> +#define HAVE_GETIPNODEBYNAME 1
> +#define HAVE_GETIPNODEBYADDR 1
> +
> #define os_strsignal strsignal
> #define OS_STRSIGNAL
>
> broke linux. There is no getipnodebyxxxx() in glibc and never be.
> getipnodebyxxxx() are obsolete in favour of get(addr|name)info().


I DID check. I logged onto a Linux box and ran "man getipnodebyaddr". I
got this:

------------------------------------------------------------------
getipnodebyname(3) Linux Programmer's Manual getipnodebyname(3)

NAME
       getipnodebyname,  getipnodebyaddr,  freehostent - get net-
       work host names and addresses


SYNOPSIS
       #include <sys/types.h>
       #include <sys/socket.h>
       #include <netdb.h>


       struct hostent *getipnodebyname(const char *name,
                                int af, int flags,
                                int *error_num);


       struct hostent *getipnodebyaddr(const void *addr,
                                size_t len, int af,
                                int *error_num);
------------------------------------------------------------------


So there certainly was getipnodebyaddr at some stage. The spec was much
the same as the Solaris version.

> Please revert this change.


I was asked to make this change because (someone asserted) gethostbyaddr
in Linux doesn't work with IPv6 addresses. (It works fine in Solaris.)

So, folks, I don't know what to do here. I have conflicting information
coming at me. What is the real story?

Meanwhile, you can set HAVE_GETIPNODEBYADDR to 0 to make Exim not try to
use it.

> ps. getaddrinfo internally uses gethostbyname2() while getnameinfo() uses
> gethostbyaddr() + gethostbyname() in glibc.


Why are there so darn many of these functions? I had heard of
gethostbyname2(), but I think that is obsolete. Solaris doesn't have it.
I haven't previously heard of get{addr,name}info().

Looks like I'll have to invent HAVE_GETADDRINFO and HAVE_GETNAMEINFO.
Sigh.

--
Philip Hazel            University of Cambridge Computing Service,
ph10@???      Cambridge, England. Phone: +44 1223 334714.