Add c-ares support for DNS resolution with timeout#323
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Signed-off-by: Björn Svensson <bjorn.a.svensson@est.tech>
When built with USE_CARES=1 (make) or -DENABLE_CARES=ON (CMake), DNS resolution in the sync API uses c-ares with a poll loop bounded by connect_timeout (defaulting to 5s). This prevents indefinite hangs when DNS is slow or unresponsive. The c-ares path uses ARES_OPT_SOCK_STATE_CB for fd tracking, and a short-lived channel per resolve call. IPv4/IPv6 fallback behavior is preserved. Without enabling c-ares, behavior is unchanged (plain getaddrinfo). Signed-off-by: Björn Svensson <bjorn.a.svensson@est.tech>
Signed-off-by: Björn Svensson <bjorn.a.svensson@est.tech>
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getaddrinfo()has no timeout mechanism. When DNS is slow or unresponsive, libvalkey hangs indefinitely with no way to cancel the lookup.This PR adds optional c-ares integration (
USE_CARES=1/-DENABLE_CARES=ON) that replacesgetaddrinfo()with c-ares driven by apoll()loop. DNS resolution respectsconnect_timeout(defaulting to 5 seconds if unset), so lookups that previously hung indefinitely now fail with a timeout error.The PR consists of two commits: the first moves existing DNS logic into
dns.[ch], and the second adds the c-ares integration.Notes:
Add non-blocking DNS for the async API via c-ares event-loop integration #324
will make DNS fully non-blocking for the async API via event-loop integration.
getaddrinfo)::1) are detected and handled correctlyTesting:
ut_dns_caresunit test covering IP literals, hostnames, non-existent hosts, IPv6, and timeoutut_connect_fallbackdisabled when c-ares is enabled (it overridesgetaddrinfowhich c-ares bypasses)