[API Proposal]: QuicError.AddressNotAvailable

[pedrobsaila]

Background and motivation

Some hosts cannot establish connection to specific addresses because Ipv6/Ipv4 are not enabled on them or more generally they don't support a specific address family. For example : when trying to establish a quic connection to an ipv6 address on a OS where ipv6 is disabled, we would get the following errors :

• Unix : An internal error has occurred. Status code: Unknown (0x63)
• Windows : An internal error has occurred. Status code: Unknown (0x80072743)

The goal of this proposal is to return a custom quic error for this case. The new enum would be mapped to :

• Unix : EAFNOSUPPORT error
• Windows : WSAENETUNREACH error

This proposal is created on behalf of this issue #74053

API Proposal

namespace System.Net.Quic;

public enum QuicError
    {
       /// <summary>
       /// The requested address is not available on this machine
       /// </summary>
       AddressNotAvailable,
    }

API Usage

try
{
// create quic connection
}
catch (QuicException ex)
{
      if (ex.QuicError == QuicError.AddressNotAvailable)
      {
              Console.WriteLine("The OS does not support this address family ")
      }
}

Alternative Designs

No response

Risks

No response

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Issue Details

---

Background and motivation

Some hosts cannot establish connection to specific addresses because Ipv6/Ipv4 is not enabled on them or more generally they don't support a specific address family. For example : when trying to establish a quic connection to an ipv6 address on a OS where ipv6 is disabled, we would get the following errors :

• Unix : An internal error has occurred. Status code: Unknown (0x63)
• Windows : An internal error has occurred. Status code: Unknown (0x80072743)

The goal of this proposal is to return a custom quic error for this case. The new enum would be mapped to :

• Unix : EAFNOSUPPORT error
• Windows : WSAENETUNREACH error

This proposal is created on behalf of this issue #74053

API Proposal

namespace System.Net.Quic;

public enum QuicError
    {
       /// <summary>
       /// The requested address is not available on the machine
       /// </summary>
       AddressNotAvailable,
    }

API Usage

try
{
// create quic connection
}
catch (QuicException ex)
{
      if (ex.QuicError == QuicError.AddressNotAvailable)
      {
              Console.WriteLine("The OS does not support this address family ")
      }
}

Alternative Designs

No response

Risks

No response

Author:	pedrobsaila
Assignees:	-
Labels:	api-suggestion, area-System.Net.Quic
Milestone:	-

[karelz]

Triage: Networking team agrees. @rzikm can you please start email-approval, given it is small? Thanks!

[bartonjs]

Video

• The two proposed inputs don't seem to both cleanly map to the same error (POSIX has ENETUNREACH which seems a better match to WSAENETUNREACH)
• There's already an existing "AddressInUse", which makes it hard for callers to understand why "NotAvailable" is different from "InUse"
• If it's (based on the EAFNOSUPPORT) address -family- not available, that should be in the name (e.g. AddressFamilyNotAvailable)
• It doesn't feel like there's actually a scenario where someone needs this value (or these values, if it's multiple), making it unclear why we're making essentially a copy of SocketError.
  • It seems like perhaps a better answer here is to expose the SocketException directly (probably wrapped by QuicException)

namespace System.Net.Quic;

public partial enum QuicError
{
    /// <summary>
    /// The requested address family is not available on this machine
    /// </summary>
    AddressNotAvailable,
}

[wfurt]

Reading this again, It feels like we should change this to AddressFamilyNotAvailable, right @pedrobsaila @ManickaP?
E.g. this is not about instance of specific address not working but really more about the type. If we agree I can take it back to API review.