Added null check for remoteIpAdress in HttpContextClientInfoProvider.GetComputerName

[Urtgard]

After an upgrade to 7.2 my app was really slow. The reason is the implementation in #6400.
remoteIpAdress can be null, but null isn't a valid input for Dns.GetHostEntry.
My log was full with this error message:

INFO  2022-06-09 15:46:20,519 [63   ] osoft.EntityFrameworkCore.Infrastructure - Entity Framework Core 6.0.5 initialized 'DbContext' using provider 'Microsoft.EntityFrameworkCore.SqlServer:6.0.5' with options: None
WARN  2022-06-09 15:46:20,524 [63   ] c.Auditing.HttpContextClientInfoProvider - System.ArgumentNullException: Value cannot be null. (Parameter 'address')
   at System.Net.Dns.GetHostEntry(IPAddress address)
   at Abp.AspNetCore.Mvc.Auditing.HttpContextClientInfoProvider.GetComputerName()

[ismcagdas]

thanks a lot @Urtgard 👍

[hzicong]

I use docker in the virtual machine,
remoteIpAddress is ::ffff:192.168.0.3
Dns.GetHostEntry(remoteIpAddress).HostName was wrong:

System.Net.Internals.SocketExceptionFactory+ExtendedSocketException (00000005, 0xFFFDFFFF): Name or service not known
at System.Net.Dns.GetHostEntryOrAddressesCore(IPAddress address, Boolean justAddresses, AddressFamily addressFamily, ValueStopwatch stopwatch)
at System.Net.Dns.GetHostEntry(IPAddress address)

[Urtgard]

Do you have performance problems as well? With errors average request time is about 60 seconds.

In one environment without a dns reverse zone I got the same error. And the same performance hit.

Maybe this shouldn't be enabled by default?

@hzicong
You could fix the dns issue. In my case a reverse zone was missing.
Or you could replace the service with your own implementation. https://aspnetboilerplate.com/Pages/Documents/Startup-Configuration#replacing-built-in-services

[hzicong]

Yes ,After upgrading to 7.2, my app takes an average of 5 seconds

[ismcagdas]

We will release the 7.3 version sooner (probably today) so you can get the fix.

[Urtgard]

@ismcagdas The update doesn't help.

I fixed just the case when remoteIpAdress is null.

In his case remoteIpAdress is not null.
But GetHostEntry cant resolve the adress and throws a SocketException.

[ismcagdas]

Maybe we should convert it back to its original verison. I will think about this, thanks.

[hzicong]

@Urtgard thanks,I replaced the service and fixed the bug.