[PATCH odhcpd v2 1/2] router: improve RA logging

[Hans Dedecker]

On Thu, Feb 16, 2023 at 9:30 PM <stijn at linux-ipv6.be> wrote:
>
> We only set the RA lifetime to what is configured in UCI when there is a
> default route and valid prefix. In any other case, we set it to 0. This
> leads to confusion where people believe ra_lifetime is completely
> ignored. In case there is a default route, but no valid prefix, a debug
> message explains this, but if there is no default route, we silently
> override ra_lifetime.
>
> Add a debug message for the latter case, and explicitly mention
> overriding ra_lifetime in both cases.
>
> Signed-off-by: Stijn Tintel <stijn at linux-ipv6.be>
Acked-by: Hans Dedecker <dedeckeh at gmail.com>
> ---
>  src/router.c | 20 +++++++++++---------
>  1 file changed, 11 insertions(+), 9 deletions(-)
>
> diff --git a/src/router.c b/src/router.c
> index 949cbe7..1c11849 100644
> --- a/src/router.c
> +++ b/src/router.c
> @@ -618,17 +618,19 @@ static int send_router_advert(struct interface *iface, const struct in6_addr *fr
>         msecs = calc_adv_interval(iface, minvalid, &maxival);
>         lifetime = calc_ra_lifetime(iface, maxival);
>
> -       if (default_route) {
> -               if (!valid_prefix) {
> -                       syslog(LOG_WARNING, "A default route is present but there is no public prefix "
> -                                       "on %s thus we don't announce a default route!", iface->name);
> -                       adv.h.nd_ra_router_lifetime = 0;
> -               } else
> -                       adv.h.nd_ra_router_lifetime = htons(lifetime < UINT16_MAX ? lifetime : UINT16_MAX);
> -
> -       } else
> +       if (default_route && valid_prefix) {
> +               adv.h.nd_ra_router_lifetime = htons(lifetime < UINT16_MAX ? lifetime : UINT16_MAX);
> +       } else {
>                 adv.h.nd_ra_router_lifetime = 0;
>
> +               if (default_route) {
> +                       syslog(LOG_WARNING, "A default route is present but there is no public prefix "
> +                                           "on %s thus we don't announce a default route by overriding ra_lifetime!", iface->name);
> +               } else {
> +                       syslog(LOG_WARNING, "No default route present, overriding ra_lifetime!");
> +               }
> +       }
> +
>         syslog(LOG_DEBUG, "Using a RA lifetime of %d seconds on %s", ntohs(adv.h.nd_ra_router_lifetime), iface->name);
>
>         /* DNS options */
> --
> 2.39.1
>