From: Baptiste Jonglez Date: Thu, 13 May 2021 17:50:22 +0000 (+0200) Subject: busybox: disable PREFER_IPV4_ADDRESS X-Git-Tag: v21.02.0-rc2~35 X-Git-Url: http://git.openwrt.org/?p=openwrt%2Fopenwrt.git;a=commitdiff_plain;h=b62fa7453a864c555fbae0ea78cb76e27d0a0a96 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 Signed-off-by: Baptiste Jonglez (cherry picked from commit 7fea9d9f5dd282a7049d77cc6b75e0a703ead26c) --- 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