ipsec: T7593: Add dynamic prefix for local and remote traffic selectors

In case when there is no local/remote prefix configured in a tunnel settings,
a protocol configured for such tunnel is ignored.

The correct way to generate the configuration is to set the prefix
to `dynamic` if it was not set. The correct config for the described case is:

```
local_ts = dynamic[gre/]
remote_ts = dynamic[gre/]
```

1 files changed, 8 insertions, 0 deletions

diff --git a/src/conf_mode/vpn_ipsec.py b/src/conf_mode/vpn_ipsec.py
index 1871956b2..dcb9f9c69 100755
--- a/src/conf_mode/vpn_ipsec.py
+++ b/src/conf_mode/vpn_ipsec.py
@@ -696,6 +696,8 @@ def generate(ipsec):
                 generate_pki_files_x509(ipsec['pki'], rw_conf['authentication']['x509'])
 
     if 'site_to_site' in ipsec and 'peer' in ipsec['site_to_site']:
+        DEFAULT_TS_PREFIX = 'dynamic'
+
         for peer, peer_conf in ipsec['site_to_site']['peer'].items():
             if f'peer_{peer}' in ipsec['dhcp_no_address']:
                 continue
@@ -724,7 +726,13 @@ def generate(ipsec):
                     passthrough = None
 
                     for local_prefix in local_prefixes:
+                        if local_prefix == DEFAULT_TS_PREFIX:
+                            continue
+
                         for remote_prefix in remote_prefixes:
+                            if remote_prefix == DEFAULT_TS_PREFIX:
+                                continue
+
                             local_net = ipaddress.ip_network(local_prefix)
                             remote_net = ipaddress.ip_network(remote_prefix)
                             if local_net.subnet_of(remote_net):