fix(snownet): invalidate allocation on channel binding error

[thomaseizinger]

When we receive an AllocationMismatch error response from the relay, it means that our local state is toast and needs to be invalidated.

• If we attempted to allocate, the corrective action is to delete the active allocation.
• If we attempted to refresh or bind a channel, the corrective action is to make a new allocation.

In the case of a channel binding, we also re-schedule the target peer to be rebound to ensure upper layers don't need to retry that. For example, if this happens during a connection setup, we still want to eventually succeed in binding the channel to ensure STUN messages as part of ICE can pass over it without having to first run into an ICE timeout and retry the entire connection.

In certain network configurations, we observed that the NAT between connlib and the relay may have fairly short session timers. Currently, allocations have a lifetime of 10 minutes and are refreshed every 5 minutes. If there is no other traffic from connlib during those 5 minutes, the NAT session might get cut and attempting to use the allocation to e.g. bind a channel doesn't work because the relay doesn't recognise the 3-tuple.

We deem these situations quite rare. Instead of keeping the NAT session alive with additional traffic, we instead implement this corrective action here which transparently creates a new allocation using our new 3-tuple.

Resolves: #6265.

[vercel]

The latest updates on your projects. Learn more about Vercel for Git ↗︎

Name	Status	Preview	Comments	Updated (UTC)
firezone	✅ Ready (Inspect)	Visit Preview	💬 Add feedback	Aug 13, 2024 7:27am

[jamilbk]

LGTM

[thomaseizinger]

I am rebasing this on top of #6276 to add more changelog entries.