On Thu, Apr 23 2020, Eric Faurot <e...@openbsd.org> wrote: > On Thu, Apr 23, 2020 at 10:34:39AM -0600, Theo de Raadt wrote: >> It says the keyword gets parsed, but then does performs no action. >> >> But that is different from not parsing it. >> >> Additionally, this explains an option which other systems support, and >> by explaining it this way, it is also explaining our behaviour in case >> of inet6 vs inet4 conditions. >> >> So... I think it should stay. Eric, do you have an opinion? > > The doc lies because the inet6 option does not set the RES_USE_INET6 > flag as stated. I think we should leave the entry in the doc but fix > the wording to say it's there for historical reasons and does nothing.
In the diff below I document the behavior on other operating systems since this looks useful to Claudio. How does it read? (I really think this should go but if it doesn't I don't want it to stay misleading as it is now.) > If we want to resurrect that option at some point, maybe we can > consider making it set the RES_USE_INET6 flag but that feels like a > bad idea right now, and this flag is apparently deprecated. I wholeheartedly with this, in my book RES_USE_INET6 and "options inet6" are just early IPv6 experiments that went nowhere. "options inet6" would break most programs that use gethostbyname(3). > But we should also fix the manpage for res_init(3) as the description > of the flag is wrong too. Diff below. Thoughts, oks? Index: share/man/man5/resolv.conf.5 =================================================================== RCS file: /d/cvs/src/share/man/man5/resolv.conf.5,v retrieving revision 1.59 diff -u -p -r1.59 resolv.conf.5 --- share/man/man5/resolv.conf.5 24 Jan 2020 06:16:47 -0000 1.59 +++ share/man/man5/resolv.conf.5 24 Apr 2020 08:22:25 -0000 @@ -259,12 +259,13 @@ as is often the case with .Xr pppoe 4 or with tunnels. .It Cm inet6 -Enables support for IPv6-only applications, by setting RES_USE_INET6 in -_res.options (see -.Xr res_init 3 ) . On .Ox this option does nothing. +On some operating systems, this option enables IPv6 support in +.Xr gethostbyname 3 +by setting RES_USE_INET6 in _res.options (see +.Xr res_init 3 ) . .It Cm insecure1 Do not require IP source address on the reply packet to be equal to the server's address. Index: lib/libc/net/res_init.3 =================================================================== RCS file: /d/cvs/src/lib/libc/net/res_init.3,v retrieving revision 1.1 diff -u -p -r1.1 res_init.3 --- lib/libc/net/res_init.3 30 Aug 2019 18:33:17 -0000 1.1 +++ lib/libc/net/res_init.3 24 Apr 2020 08:25:46 -0000 @@ -180,12 +180,14 @@ In the past, it turned off the legacy .Ev HOSTALIASES feature. .It Dv RES_USE_INET6 -Enables support for IPv6-only applications. -This causes IPv4 addresses to be returned as an IPv4 mapped address. +With this option +.Xr gethostbyname 3 +will return IPv6 addresses if available. +On some operating systems this option also causes IPv4 addresses to be +returned as IPv4-mapped IPv6 addresses. For example, 10.1.1.1 will be returned as ::ffff:10.1.1.1. -On -.Ox -this option does nothing. +IPv4-mapped IPv6 addresses are not supported on +.Ox . .It Dv RES_USE_EDNS0 Attach an OPT pseudo-RR for the EDNS0 extension, as specified in RFC 2671. -- jca | PGP : 0x1524E7EE / 5135 92C1 AD36 5293 2BDF DDCC 0DFA 74AE 1524 E7EE
