On Tue, Mar 12, 2024 at 07:21:10PM +0100, Stefano Brivio wrote:

We might have read from resolv.conf, or from the command line, a resolver that's reachable via loopback address, but that doesn't mean we can offer that via DHCP, NDP or DHCPv6: warn if there are no resolvers we can offer for a given IP version.

Suggested-by: David Gibson Signed-off-by: Stefano Brivio

Reviewed-by: David Gibson

--- conf.c | 17 +++++++++++++++-- 1 file changed, 15 insertions(+), 2 deletions(-)

diff --git a/conf.c b/conf.c index 17c667a..ac9fb34 100644 --- a/conf.c +++ b/conf.c @@ -464,8 +464,21 @@ static void get_dns(struct ctx *c) close(fd);

out: - if (!dns_set && !added) - warn("Couldn't get any nameserver address"); + if (!dns_set) { + if (!added) + warn("Couldn't get any nameserver address"); + + if (c->no_dhcp_dns) + return; + + if (c->ifi4 && !c->no_dhcp && + IN4_IS_ADDR_UNSPECIFIED(&c->ip4.dns[0])) + warn("No IPv4 nameserver available for DHCP"); + + if (c->ifi6 && ((!c->no_ndp && !c->no_ra) || !c->no_dhcpv6) && + IN6_IS_ADDR_UNSPECIFIED(&c->ip6.dns[0])) + warn("No IPv6 nameserver available for NDP/DHCPv6"); + } }

/**

-- David Gibson | I'll have my music baroque, and my code david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_ | _way_ _around_! http://www.ozlabs.org/~dgibson