T7458: Fix VPN IPsec unexpected passthrough logic bug

VPN IPsec unexpected passthrough logic bug was introduced in this
commit https://github.com/vyos/vyos-1x/commit/f480346bb8e934b1ce2e0fc3be23f7168273bba1
The correct behaviour of the `cidr_fit` was replaced with the
incorrect `overlap`

This way, the passthrough option is used every time when networks overlap.

```
>>> from ipaddress import ip_network
>>>
>>> a = ip_network('192.0.2.0/24')
>>> b = ip_network('192.0.2.100/30')
>>>
>>> a.overlaps(b)
True
>>>
>>> b.overlaps(a)
True
>>>
```

But there should be `subnet_of`:
```
>>> a.subnet_of(b)
False
>>>
>>> b.subnet_of(a)
True
>>>
```

In configuration it looks like
```
set vpn ipsec site-to-site peer RIGHT tunnel 0 local prefix '192.0.2.0/24'
set vpn ipsec site-to-site peer RIGHT tunnel 0 remote prefix '192.0.2.100/30'
```
The StrongSwan unexpected configuration:
```
            RIGHT-tunnel-0-passthrough {
                local_ts = 192.0.2.0/24
                remote_ts = 192.0.2.0/24
                start_action = trap
                mode = pass
            }
```

So all outcoming traffic to the 192.0.2.0/24 pass through the main routing
table instead of out SA

Use `subnet_of` to fix this

0 files changed, 0 insertions, 0 deletions