Attachment 1471909 Details for Bug 1607967 – Backport (part 2)

[patch] Backport (part 2)

0002-greendns-udp-Fix-infinite-loop-when-source-address-m.patch (text/plain), 1.99 KB, created by Lon Hohberger on 2018-07-31 18:59:14 UTC

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Creator: Lon Hohberger

Created: 2018-07-31 18:59:14 UTC

Size: 1.99 KB

patch

obsolete

>From 27457b3b8dd8e530efcb337a160e5862807f539f Mon Sep 17 00:00:00 2001
>From: Lon Hohberger <lon@metamorphism.com>
>Date: Tue, 31 Jul 2018 08:12:43 -0400
>Subject: [PATCH 2/3] greendns udp: Fix infinite loop when source address
> mismatch
>
>If the source address for a packet did not match where we sent,
>the udp() function would spin in an infinite loop and the timer
>would never expire, causing the process to hang.
>
>Signed-off-by: Lon Hohberger <lon@metamorphism.com>
>---
> eventlet/support/greendns.py | 18 ++++++++++++++----
> 1 file changed, 14 insertions(+), 4 deletions(-)
>
>diff --git a/eventlet/support/greendns.py b/eventlet/support/greendns.py
>index 3ecbc9b..0e03113 100644
>--- a/eventlet/support/greendns.py
>+++ b/eventlet/support/greendns.py
>@@ -696,14 +696,24 @@ def udp(q, where, timeout=DNS_QUERY_TIMEOUT, port=53,
>             # Q: Do we also need to catch coro.CoroutineSocketWake and pass?
>             if expiration - time.time() <= 0.0:
>                 raise dns.exception.Timeout
>-        while 1:
>+            eventlet.sleep(0.01)
>+
>+        tried = False
>+        while True:
>+            # If we've tried to receive at least once, check to see if our
>+            # timer expired
>+            if tried and (expiration - time.time() <= 0.0):
>+                raise dns.exception.Timeout
>+            # Sleep if we are retrying the operation due to a bad source
>+            # address or a socket timeout.
>+            if tried:
>+                eventlet.sleep(0.01)
>+            tried = True
>+
>             try:
>                 (wire, from_address) = s.recvfrom(65535)
>             except socket.timeout:
>                 # Q: Do we also need to catch coro.CoroutineSocketWake and pass?
>-                if expiration - time.time() <= 0.0:
>-                    raise dns.exception.Timeout
>-                eventlet.sleep(0.01)
>                 continue
>             if dns.inet.af_for_address(from_address[0]) == dns.inet.AF_INET6:
>                 # Purge all possible zeroes for ipv6 to match above logic
>-- 
>2.13.6
>

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