Update documentation

README.md

@@ -58,6 +58,10 @@ $ nsxanalyzer --resource-input-file pkg/collector/data/json/Example2.json --outp
 ```
 ![graph](pkg/collector/data/expected_output/ex2Filter1.svg)
 
+
+## NSX Supported API versions and resources
+See documentation [here](docs/nsx_support.md).
+
 ## Build the project
 
 Make sure you have golang 1.23+ on your platform

docs/nsx_support.md

@@ -0,0 +1,37 @@
+# NSX supported resources
+
+
+### API Version
+
+See [NSX REST API](https://developer.broadcom.com/xapis/nsx-t-data-center-rest-api/latest/).
+
+
+### DFW supported fields
+
+Features not yet supported:
+
+* Category of type `Ethernet`
+* Supported protocols: `TCP`, `UDP`, `ICMP`
+* Rules fields `SourcesExcluded`, `DestinationsExcluded`
+* Rules fields `DestinationGroups`, `SourceGroups` with  IP Addresses.
+
+
+
+### Topology resources 
+
+Following resources are considered for the analysis:
+* VMs
+* Segments 
+* T1 Gateway
+* T0 Gateway
+
+
+### Endpoints 
+
+The analysis endpoints are the VMs retrieved from `GET api/v1/fabric/virtual-machines`.
+
+
+### More limitations and assumptions
+
+* Currently IPv6 protocols and addresses are not supported. 
+* Assuming single NSX domain.

pkg/collector/data_model.go

@@ -117,7 +117,7 @@ type ICMPTypeServiceEntry struct {
 }
 
 func (e *ICMPTypeServiceEntry) ToConnection() (*netset.TransportSet, error) {
-	if e.Protocol == nil || *e.Protocol == nsx.ICMPTypeServiceEntryProtocolICMPv6 {
+	if e.Protocol != nil && *e.Protocol == nsx.ICMPTypeServiceEntryProtocolICMPv6 {
 		return nil, fmt.Errorf("protocol %s of ICMPTypeServiceEntry  \"%s\" is not supported", *e.Protocol, *e.DisplayName)
 	}
 	var tMin, tMax int64 = 0, int64(netp.MaxICMPType)
@@ -146,6 +146,9 @@ type L4PortSetServiceEntry struct {
 }
 
 func (e *L4PortSetServiceEntry) ToConnection() (*netset.TransportSet, error) {
+	if e.L4Protocol == nil {
+		return nil, fmt.Errorf("L4PortSetServiceEntry object has nil L4Protocol")
+	}
 	res := netset.NoTransports()
 	protocol := netp.ProtocolString(*e.L4Protocol)
 	srcPorts, err := parsePorts(e.SourcePorts)