On Fri, Nov 15, 2024 at 03:22:06PM +0100, Stefano Brivio wrote:

ndp_timer() is called right away on the first epoll_wait() cycle, when the communication channel to the guest isn't ready yet:

1.0038: NDP: sending unsolicited RA, next in 264s 1.0038: tap: failed to send 1 frames of 1

check that it's up before sending it. This effectively delays the first gratuitous router advertisement, which is probably a good idea given that we expect the guest to send a router solicitation right away.

Fixes: 6e1e44293ef9 ("ndp: Send unsolicited Router Advertisements") Signed-off-by: Stefano Brivio

Reviewed-by: David Gibson I spotted another buglet in the RA stuff shortly after I sent it: we should suppress calling ndp_timer() at all if c->no_ndp, but I forgot to test for it.

--- Oops, I sent a previous/wrong version of the patch as v1.

ndp.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/ndp.c b/ndp.c index 7ee44b2..1752d64 100644 --- a/ndp.c +++ b/ndp.c @@ -391,7 +391,7 @@ void ndp_timer(const struct ctx *c, const struct timespec *now) time_t max_rtr_adv_interval = DEFAULT_MAX_RTR_ADV_INTERVAL; time_t min_rtr_adv_interval, interval;

- if (c->no_ra || now->tv_sec < next_ra) + if (c->fd_tap < 0 || c->no_ra || now->tv_sec < next_ra) return;

/* We must advertise before the route's lifetime expires */

-- 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