On Sat, May 26, 2018 at 08:27:47AM -0400, John Ferlan wrote:
In a previous commit:
commit d4bf8f415074759baf051644559e04fe78888f8b Author: Daniel P. Berrangé <berrange@redhat.com> Date: Wed Feb 14 09:43:59 2018 +0000
nwfilter: handle missing switch enum cases
Ensure all enum cases are listed in switch statements, or cast away enum type in places where we don't wish to cover all cases.
Reviewed-by: John Ferlan <jferlan@redhat.com> Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
we changed a switch in the nwfilter learning thread so that it had explict cases for all enum entries. Unfortunately the parameters in the method had been declared with incorrect type. The "howDetect" parameter does *not* accept "enum howDetect" values, rather it accepts a bitmask of "enum howDetect" values, so it should have been an "int" type.
The caller always passes DETECT_STATIC|DETECT_DHCP, so essentially the IP addressing learning was completely broken by the above change, as it never matched any switch case, hitting the default leading to EINVAL.
Rather than treat the howDetect as a numerical enum, let's treat it as a bitmask/flag since that's the way it's used. Thus, the switch changes to a simple if bit is set keeping the original intention that if @howDetect == DETECT_DHCP, then use applyDHCPOnlyRules; otherwise, use applyBasicRules to determine the IP Address.
Proposed-by: Daniel P. Berrangé <berrange@redhat.com> Signed-off-by: John Ferlan <jferlan@redhat.com> ---
Here's to hoping I've used the correct magic incantation to get this to reply to Daniel's poll series as this should be pushed in conjunction with that (and thus would need review). This should be done before the 4.4.0 release.
BTW: This also fixes a strange phenomena I was seeing in my testing environment where domain startups would periodically fail with:
error: Failed to start domain f23 error: Machine 'qemu-6-f23' already exists
but could be started with enough retry attempts. What causes me to believe there's a relationship with this series is that if running libvirtd debug, I see the following as output:
Detaching after fork from child process 22442. 2018-05-25 20:37:24.966+0000: 25923: error : virSystemdCreateMachine:361 : Machine 'qemu-6-f23' already exists 2018-05-25 20:37:24.988+0000: 22440: error : learnIPAddressThread:668 : encountered an error on interface vnet0 index 150: Invalid argument [Thread 0x7fffacdb7700 (LWP 22440) exited]
With these two patches in place, no more errors.
src/nwfilter/nwfilter_learnipaddr.c | 27 +++++++++++++-------------- src/nwfilter/nwfilter_learnipaddr.h | 10 +++++----- 2 files changed, 18 insertions(+), 19 deletions(-)
diff --git a/src/nwfilter/nwfilter_learnipaddr.c b/src/nwfilter/nwfilter_learnipaddr.c index 506b98fd07..ab2697274c 100644 --- a/src/nwfilter/nwfilter_learnipaddr.c +++ b/src/nwfilter/nwfilter_learnipaddr.c @@ -145,7 +145,7 @@ struct _virNWFilterIPAddrLearnReq { char *filtername; virHashTablePtr filterparams; virNWFilterDriverStatePtr driver; - enum howDetect howDetect; + virNWFilterLearnIPHowDetectFlags howDetect;
We don't normally use typedefs for bitmasks because they are misleading as evidenced by this bug. So I still prefer my original patch that uses 'int'. We could just simplify the code though. Given that it is hardcoded to always pass DETECT_DHCP | DETECT_STATIC, there's little obvious point in it being configurable right now, so we could just remove the enum entirely and hardwire the only thing we actually use. Regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|