ndp: Don't send unsolicited router advertisement if we can't, yet

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 <sbrivio@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>

1 files changed, 1 insertions, 1 deletions

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 */