IPv4 connections are retried forever in heartbeat_sender if open() fails,
so a temporary network outage does not terminate the sender.
IPv6 connections that have never opened successfully are dropped after
IPV6_EARLY_FAIL_LIMIT (3) consecutive failures so that a network without
IPv6 support does not keep a dead sender running.
At startup all resolved connections are added to the list regardless of
whether the initial open() succeeds; the heartbeat_sender loop handles
the first real connection attempt.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
andreas
11d1c718b3