From 35d8fb05017af9ee8514cb317cb37fc2ce5185a9 Mon Sep 17 00:00:00 2001 From: Phil Blundell Date: Tue, 13 Jan 2009 11:51:04 +0000 Subject: - ares__send_query() now varies the retry timeout pseudo-randomly to avoid packet storms when several queries were started at the same time. --- ares/CHANGES | 6 +++++- ares/ares_process.c | 5 ++++- 2 files changed, 9 insertions(+), 2 deletions(-) diff --git a/ares/CHANGES b/ares/CHANGES index 1c6b6070b..5bb02f744 100644 --- a/ares/CHANGES +++ b/ares/CHANGES @@ -1,6 +1,10 @@ Changelog for the c-ares project -* January 11 2008 (Daniel Stenberg) +* January 13 2009 (Phil Blundell) +- ares__send_query() now varies the retry timeout pseudo-randomly to avoid + packet storms when several queries were started at the same time. + +* January 11 2009 (Daniel Stenberg) - Phil Blundell added the internal function ares__expand_name_for_response() that is now used by the ares_parse_*_reply() functions instead of the ares_expand_name() simply to easier return ARES_EBADRESP for the cases where diff --git a/ares/ares_process.c b/ares/ares_process.c index 8c25b11da..3aa75cdae 100644 --- a/ares/ares_process.c +++ b/ares/ares_process.c @@ -715,6 +715,7 @@ void ares__send_query(ares_channel channel, struct query *query, { struct send_request *sendreq; struct server_state *server; + int timeplus; server = &channel->servers[query->server]; if (query->using_tcp) @@ -778,9 +779,11 @@ void ares__send_query(ares_channel channel, struct query *query, return; } } + timeplus = channel->timeout << (query->try / channel->nservers); + timeplus = (timeplus * (9 + (rand () & 7))) / 16; query->timeout = *now; ares__timeadd(&query->timeout, - channel->timeout << (query->try / channel->nservers)); + timeplus); /* Keep track of queries bucketed by timeout, so we can process * timeout events quickly. */ -- cgit v1.2.3