Re: lib/42405: libc: getaddrinfo() should perform T_A lookups before T_AAAA lookups

["Greg A. Woods" <woods%planix.ca@localhost>]

The following reply was made to PR lib/42405; it has been noted by GNATS.

From: "Greg A. Woods" <woods%planix.ca@localhost>
To: NetBSD GNATS <gnats-bugs%NetBSD.org@localhost>
Cc: lib-bug-people%netbsd.org@localhost,
        NetBSD GNATS Administrator <gnats-admin%NetBSD.org@localhost>,
        cswiger%mac.com@localhost
Subject: Re: lib/42405: libc: getaddrinfo() should perform T_A lookups before 
T_AAAA lookups
Date: Fri, 04 Dec 2009 16:47:39 -0500

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 At Fri,  4 Dec 2009 14:15:05 +0000 (UTC), Martin Husemann <martin@duskware.=
 de> wrote:
 Subject: Re: lib/42405: libc: getaddrinfo() should perform T_A lookups befo=
 re T_AAAA lookups
 >=20
 > The following reply was made to PR lib/42405; it has been noted by GNATS.
 >=20
 > From: Martin Husemann <martin%duskware.de@localhost>
 > To: gnats-bugs%NetBSD.org@localhost
 > Cc:=20
 > Subject: Re: lib/42405: libc: getaddrinfo() should perform T_A lookups be=
 fore T_AAAA lookups
 > Date: Fri, 4 Dec 2009 15:13:28 +0100
 >=20
 >  On Thu, Dec 03, 2009 at 11:00:15PM +0000, Matthias Scheler wrote:
 >  >  The behaviour should not be hard-coded, it should be configurable.
 > =20
 >  I agree.
 >  The behaviour might have been a good idea in 2005, but now we either sho=
 uld
 >  stick with our current behaviour or make it /etc/resolv.conf configurabl=
 e.
 
 FYI, /etc/resolv.conf already includes an option which can be enabled to
 encourage IPv6 DNS lookups ("options inet6" which turns on RES_USE_INET6)
 
 Also, if !defined(INET6) then it should _NEVER_ "prefer" IPv6 lookups.
 Half the rest of getaddrinfo.c respects INET6, so I don't know why it
 didn't go all the way.
 
 I think this change fixes the second complaint:
 
 Index: getaddrinfo.c
 =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
 =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
 =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
 RCS file: /cvs/master/m-NetBSD/main/src/lib/libc/net/getaddrinfo.c,v
 retrieving revision 1.87.2.1
 diff -u -u -r1.87.2.1 getaddrinfo.c
 --- getaddrinfo.c      31 Jan 2009 21:43:33 -0000      1.87.2.1
 +++ getaddrinfo.c      4 Dec 2009 21:43:11 -0000
 @@ -1293,6 +1293,7 @@
 =20
        switch (pai->ai_family) {
        case AF_UNSPEC:
 +#ifdef INET6
                /* prefer IPv6 */
                q.name =3D name;
                q.qclass =3D C_IN;
 @@ -1306,6 +1307,9 @@
                q2.answer =3D buf2->buf;
                q2.anslen =3D sizeof(buf2->buf);
                break;
 +#else
 +              /* FALLTHROUGH */
 +#endif
        case AF_INET:
                q.name =3D name;
                q.qclass =3D C_IN;
 @@ -1346,6 +1350,7 @@
                        cur =3D cur->ai_next;
        }
        if (q.next) {
 +              /* xxx this looks bogus -- it could/should de-reference q.next 
to find q=
 2! */
                ai =3D getanswer(buf2, q2.n, q2.name, q2.qtype, pai);
                if (ai)
                        cur->ai_next =3D ai;
 
 
 --=20
                                                Greg A. Woods
                                                Planix, Inc.
 
 <woods%planix.com@localhost>       +1 416 218 0099        
http://www.planix.com/
 
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