…onses.

- Implement tracking of individual IP TTLs for FQDNs in the DNS cache.
- Upon expiration of an IP's TTL, trigger a new DNS query.
- Evict only those IPs that are no longer present in the latest DNS response and have exceeded their original TTL.

Signed-off-by: Hemant <hkbiet@gmail.com>

 - Replace time.Now() usages with the clock set in fqdnController.
 - Inject fakeClock for tests.
Removed mockDnsQueryQueue implementation.

Signed-off-by: Hemant <hkbiet@gmail.com>

…upport

- Implement tracking of TTLs for individual IPs linked to FQDNs in the DNS cache.
- Automatically trigger a new DNS query when an IP's TTL expires.
- Evict only those IPs that are no longer present in the latest DNS response and have surpassed their original TTL.
- Added clock field of type clock.Clock in fqdnController.
- Pass clock while initializing fqdn controller.

Signed-off-by: Hemant <hkbiet@gmail.com>

…antrea into cache-individual-ip-ttl

Signed-off-by: Hemant <hkbiet@gmail.com>

Signed-off-by: Hemant <hkbiet@gmail.com>

…tuality test to 1 second

Signed-off-by: Hemant <hkbiet@gmail.com>

…ueue.

Updated onDNSResponse() to requeue DNS queries even when same IPs are receieved in a response.
Added and updated comments as per review.

Signed-off-by: Hemant <hkbiet@gmail.com>

Signed-off-by: Hemant <hkbiet@gmail.com>

Updated comment clarifying the case when ipWithExpirationMap is of zero length in onDNSResponse.
Updated test case which ensures the requery time to be the later time amongst the TTL already cached and TTL received in DNS response for cases involving same IPs, as present in DNS cache, being received.

Signed-off-by: Hemant <hkbiet@gmail.com>

regplaced dnsQueryQueue.AddAfter logic as before.

Signed-off-by: Hemant <hkbiet@gmail.com>

…ts from external imports

Signed-off-by: Hemant <hkbiet@gmail.com>

…NSResponse test.

- Seemingly a race condition between the event of creation of Timer by DelayeingQueue and Step function of fakeClock is failing the test.
- The fix Uses the idea in antrea-io#6407
- The fix uses the ,already implemented wrapper, around fakeClock with a method that counts the number of times DelayedQueue's Timer has been called.

Signed-off-by: Hemant <hkbiet@gmail.com>

Signed-off-by: Hemant <hkbiet@gmail.com>