c-ares

A C library for asynchronous DNS requests (grpc依赖)

Oliver Welsh fd81f36d3e Add server failover retry behavior, where failed servers are retried with small probability after a minimum delay (#731 ) Summary By default c-ares will select the server with the least number of consecutive failures when sending a query. However, this means that if a server temporarily goes down and hits failures (e.g. a transient network issue), then that server will never be retried until all other servers hit the same number of failures. This is an issue if the failed server is preferred to other servers in the list. For example if a primary server and a backup server are configured. This PR adds new server failover retry behavior, where failed servers are retried with small probability after a minimum delay has passed. The probability and minimum delay are configurable via the `ARES_OPT_SERVER_FAILOVER` option. By default c-ares will use a probability of 10% and a minimum delay of 5 seconds. In addition, this PR includes a small change to always close out connections to servers which have hit failures, even with `ARES_FLAG_STAYOPEN`. It's possible that resetting the connection can resolve some server issues (e.g. by resetting the source port). Testing A new set of regression tests have been added to test the new server failover retry behavior. Fixes Issue: #717 Fix By: Oliver Welsh (@oliverwelsh)		8 months ago
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CMakeLists.txt	make dns parser/writer public (#604 )	1 year ago
Makefile.am	make dns parser/writer public (#604 )	1 year ago
ares.h	Add server failover retry behavior, where failed servers are retried with small probability after a minimum delay (#731 )	8 months ago
ares_build.h.cmake	no reason to include sys/random.h all the time (#684 )	11 months ago
ares_build.h.dist	Update from 1989 MIT license text to modern MIT license text (#556 )	1 year ago
ares_build.h.in	no reason to include sys/random.h all the time (#684 )	11 months ago
ares_dns.h	Reformat code using clang-format (#579 )	1 year ago
ares_dns_record.h	clang-format	8 months ago
ares_nameser.h	Fix typos discovered by codespell (#634 )	1 year ago
ares_rules.h	Reformat code using clang-format (#579 )	1 year ago
ares_version.h	release prep for 1.28.1 (#739 )	8 months ago