Re: [PATCH v2 3/9] conf: Refactor conf_print() for multi-address support

[David Gibson <david@gibson.dropbear.id.au>]

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On Sun, Jan 18, 2026 at 05:16:06PM -0500, Jon Maloy wrote:
> As a preparation for multiple address support, we refactor the
> conf_print() function to handle this properly.
> 
> Signed-off-by: Jon Maloy <jmaloy@redhat.com>
> ---
>  conf.c | 78 +++++++++++++++++++++++++++++++++-------------------------
>  1 file changed, 45 insertions(+), 33 deletions(-)
> 
> diff --git a/conf.c b/conf.c
> index 9fc5dca..3ecd1a0 100644
> --- a/conf.c
> +++ b/conf.c
> @@ -1199,20 +1199,28 @@ static void conf_print(const struct ctx *c)
>  				       buf4, sizeof(buf4)));
>  
>  		if (!c->no_dhcp) {
> -			uint32_t mask;
> -
> -			mask = htonl(0xffffffff <<
> -				     (32 - c->ip4.addrs[0].prefix_len));
> -
> -			info("DHCP:");
> -			info("    assign: %s",
> -			     inet_ntop(AF_INET, inany_v4(&c->ip4.addrs[0].addr),
> -				       buf4, sizeof(buf4)));
> -			info("    mask: %s",
> -			     inet_ntop(AF_INET, &mask,        buf4, sizeof(buf4)));
> -			info("    router: %s",
> -			     inet_ntop(AF_INET, &c->ip4.guest_gw,
> -				       buf4, sizeof(buf4)));
> +			for (i = 0; i < c->ip4.addr_count; i++) {
> +				const struct inany_addr_entry *e;
> +				uint32_t mask;
> +
> +				e = &c->ip4.addrs[i];
> +				if (!(e->flags & INANY_ADDR_CONFIGURED) &&
> +				    c->ip4.addr_count > 1)
> +					continue;

This doesn't seem right - addresses taken from the host will also be
used for DHCP.

> +
> +				mask = htonl(0xffffffff << (32 - e->prefix_len));
> +
> +				info("DHCP:");
> +				info("    assign: %s",
> +				     inet_ntop(AF_INET, inany_v4(&e->addr),
> +					       buf4, sizeof(buf4)));
> +				info("    mask: %s",
> +				     inet_ntop(AF_INET, &mask, buf4, sizeof(buf4)));
> +				info("    router: %s",
> +				     inet_ntop(AF_INET, &c->ip4.guest_gw,
> +					       buf4, sizeof(buf4)));
> +				break;
> +			}
>  		}
>  
>  		for (i = 0; !IN4_IS_ADDR_UNSPECIFIED(&c->ip4.dns[i]); i++) {
> @@ -1230,30 +1238,34 @@ static void conf_print(const struct ctx *c)
>  	}
>  
>  	if (c->ifi6) {
> +		bool do_slaac = !c->no_ndp || !c->no_dhcpv6;
> +
>  		if (!IN6_IS_ADDR_UNSPECIFIED(&c->ip6.map_host_loopback))
>  			info("    NAT to host ::1: %s",
>  			     inet_ntop(AF_INET6, &c->ip6.map_host_loopback,
>  				       buf6, sizeof(buf6)));
>  
> -		if (!c->no_ndp && !c->no_dhcpv6)
> -			info("NDP/DHCPv6:");
> -		else if (!c->no_dhcpv6)
> -			info("DHCPv6:");
> -		else if (!c->no_ndp)
> -			info("NDP:");
> -		else
> -			goto dns6;
> -
> -		info("    assign: %s",
> -		     inet_ntop(AF_INET6, &c->ip6.addrs[0].addr.a6,
> -			       buf6, sizeof(buf6)));
> -		info("    router: %s",
> -		     inet_ntop(AF_INET6, &c->ip6.guest_gw, buf6, sizeof(buf6)));
> -		info("    our link-local: %s",
> -		     inet_ntop(AF_INET6, &c->ip6.our_tap_ll,
> -			       buf6, sizeof(buf6)));
> -
> -dns6:
> +		if (do_slaac) {
> +			if (!c->no_ndp && !c->no_dhcpv6)
> +				info("NDP/DHCPv6:");
> +			else if (!c->no_dhcpv6)
> +				info("DHCPv6:");
> +			else
> +				info("NDP:");
> +
> +			for (i = 0; i < c->ip6.addr_count; i++) {
> +				info("    assign: %s",
> +				     inet_ntop(AF_INET6, &c->ip6.addrs[i].addr.a6,
> +					       buf6, sizeof(buf6)));

There's an inany_ntop()... if you're going to use inany_ntop() for
IPv6 only addresses you might at least use the helper functions
already implemented for it.

> +			}
> +			info("    router: %s",
> +			     inet_ntop(AF_INET6, &c->ip6.guest_gw,
> +				       buf6, sizeof(buf6)));
> +			info("    our link-local: %s",
> +			     inet_ntop(AF_INET6, &c->ip6.our_tap_ll,
> +				       buf6, sizeof(buf6)));
> +		}
> +
>  		for (i = 0; !IN6_IS_ADDR_UNSPECIFIED(&c->ip6.dns[i]); i++) {
>  			if (!i)
>  				info("DNS:");
> -- 
> 2.52.0
> 

-- 
David Gibson (he or they)	| 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

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