[openwrt/openwrt] busybox: disable PREFER_IPV4_ADDRESS

[LEDE Commits]

zorun pushed a commit to openwrt/openwrt.git, branch openwrt-21.02:
https://git.openwrt.org/b62fa7453a864c555fbae0ea78cb76e27d0a0a96

commit b62fa7453a864c555fbae0ea78cb76e27d0a0a96
Author: Baptiste Jonglez <git at bitsofnetworks.org>
AuthorDate: Thu May 13 19:50:22 2021 +0200

    busybox: disable PREFER_IPV4_ADDRESS
    
    PREFER_IPV4_ADDRESS is broken on IPv6-only hosts, as it causes busybox
    utilities (ping, traceroute, ntpd) to forcibly use the A record instead of
    the AAAA record when resolving a DNS name.  This obviously fails when
    there is no IPv4 connectivity.  Since IPv6-only hosts or routers will only
    become more common over time, disable PREFER_IPV4_ADDRESS to support this
    use-case.
    
    As a side-effect, disabling PREFER_IPV4_ADDRESS changes the default
    resolution behaviour of busybox utilities on dual-stack hosts.  Busybox
    utilities now simply use the order given by getaddrinfo(), so they will
    now prefer IPv6 addresses when resolving a name with both A and AAAA
    records if there is IPv6 connectivity.  This is in line with RFC 6724.
    
    PREFER_IPV4_ADDRESS was likely intended to work around naive
    implementations of getaddrinfo() that could return AAAA records first,
    even on an IPv4-only host.  But both musl (since 1.1.3) and glibc
    correctly implement RFC 6724 for getaddrinfo() and check connectivity to
    determine the correct order in which to return records.  On IPv4-only
    hosts, getaddrinfo() will return A records first, so there is no need for
    the PREFER_IPV4_ADDRESS hack.
    
    See also: https://bugs.busybox.net/show_bug.cgi?id=12381
    
    Fixes: FS#84
    Fixes: FS#2608
    References: https://github.com/openwrt/openwrt/pull/4167
    Signed-off-by: Alexander Traud <pabstraud at compuserve.com>
    Signed-off-by: Baptiste Jonglez <git at bitsofnetworks.org>
    (cherry picked from commit 7fea9d9f5dd282a7049d77cc6b75e0a703ead26c)
---
 package/utils/busybox/Config-defaults.in | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/package/utils/busybox/Config-defaults.in b/package/utils/busybox/Config-defaults.in
index 04148df267..168c73b24c 100644
--- a/package/utils/busybox/Config-defaults.in
+++ b/package/utils/busybox/Config-defaults.in
@@ -2192,7 +2192,7 @@ config BUSYBOX_DEFAULT_FEATURE_UNIX_LOCAL
 	default n
 config BUSYBOX_DEFAULT_FEATURE_PREFER_IPV4_ADDRESS
 	bool
-	default y
+	default n
 config BUSYBOX_DEFAULT_VERBOSE_RESOLUTION_ERRORS
 	bool
 	default y