add MAC, IPv4, IPv6 addresses to nework inspect

Signed-off-by: Arjun Raja Yogidas <arjunry@amazon.com>

Author: coderbirju

cmd/nerdctl/network/network_inspect_test.go

@@ -397,6 +397,64 @@ func TestNetworkInspect(t *testing.T) {
 				}
 			},
 		},
+		{
+			Description: "Test container network details",
+			Setup: func(data test.Data, helpers test.Helpers) {
+				helpers.Ensure("network", "create", data.Identifier("test-network"))
+
+				// See https://github.com/containerd/nerdctl/issues/4322
+				if runtime.GOOS == "windows" {
+					time.Sleep(time.Second)
+				}
+
+				// Create and start a container on this network
+				helpers.Ensure("run", "-d", "--name", data.Identifier("test-container"),
+					"--network", data.Identifier("test-network"),
+					testutil.CommonImage, "sleep", nerdtest.Infinity)
+
+				// Get container ID for later use
+				containerID := strings.Trim(helpers.Capture("inspect", data.Identifier("test-container"), "--format", "{{.Id}}"), "\n")
+				data.Labels().Set("containerID", containerID)
+			},
+			Cleanup: func(data test.Data, helpers test.Helpers) {
+				helpers.Anyhow("rm", "-f", data.Identifier("test-container"))
+				helpers.Anyhow("network", "remove", data.Identifier("test-network"))
+			},
+			Command: func(data test.Data, helpers test.Helpers) test.TestableCommand {
+				return helpers.Command("network", "inspect", data.Identifier("test-network"))
+			},
+			Expected: func(data test.Data, helpers test.Helpers) *test.Expected {
+				return &test.Expected{
+					Output: func(stdout string, t tig.T) {
+						var dc []dockercompat.Network
+						err := json.Unmarshal([]byte(stdout), &dc)
+						assert.NilError(t, err, "Unable to unmarshal output")
+						assert.Equal(t, 1, len(dc), "Expected exactly one network")
+
+						network := dc[0]
+						assert.Equal(t, network.Name, data.Identifier("test-network"))
+						assert.Equal(t, 1, len(network.Containers), "Expected exactly one container")
+
+						// Get the container details
+						containerID := data.Labels().Get("containerID")
+						container := network.Containers[containerID]
+
+						// Test container name
+						assert.Equal(t, container.Name, data.Identifier("test-container"))
+
+						// Test IPv4Address has CIDR notation (not empty and contains '/')
+						assert.Assert(t, container.IPv4Address != "", "IPv4Address should not be empty")
+						assert.Assert(t, strings.Contains(container.IPv4Address, "/"), "IPv4Address should contain CIDR notation with /")
+
+						// Test MacAddress is present and has valid format
+						assert.Assert(t, container.MacAddress != "", "MacAddress should not be empty")
+
+						// Test IPv6Address is empty for IPv4-only network
+						assert.Equal(t, "", container.IPv6Address, "IPv6Address should be empty for IPv4-only network")
+					},
+				}
+			},
+		},
 	}
 
 	testCase.Run(t)

pkg/inspecttypes/dockercompat/dockercompat.go

@@ -929,9 +929,9 @@ type Network struct {
 type EndpointResource struct {
 	Name string `json:"Name"`
 	// EndpointID  string `json:"EndpointID"`
-	// MacAddress  string `json:"MacAddress"`
-	// IPv4Address string `json:"IPv4Address"`
-	// IPv6Address string `json:"IPv6Address"`
+	MacAddress  string `json:"MacAddress"`
+	IPv4Address string `json:"IPv4Address"`
+	IPv6Address string `json:"IPv6Address"`
 }
 
 type structuredCNI struct {
@@ -949,6 +949,88 @@ type MemorySetting struct {
 	DisableOOMKiller bool  `json:"disableOOMKiller"`
 }
 
+// parseNetworkSubnets extracts and parses subnet configurations from IPAM config
+func parseNetworkSubnets(ipamConfigs []IPAMConfig) []*net.IPNet {
+	var subnets []*net.IPNet
+	for _, config := range ipamConfigs {
+		if config.Subnet != "" {
+			_, subnet, err := net.ParseCIDR(config.Subnet)
+			if err != nil {
+				log.L.WithError(err).Warnf("failed to parse subnet %q", config.Subnet)
+				continue
+			}
+			subnets = append(subnets, subnet)
+		}
+	}
+	return subnets
+}
+
+// isUsableInterface checks if a network interface is usable (not loopback and up)
+func isUsableInterface(iface *native.NetInterface) bool {
+	return iface.Interface.Flags&net.FlagLoopback == 0 &&
+		iface.Interface.Flags&net.FlagUp != 0
+}
+
+// setIPAddresses assigns IPv4 or IPv6 addresses from CIDR notation to the endpoint
+func setIPAddresses(endpoint *EndpointResource, cidr string) {
+	ip, _, err := net.ParseCIDR(cidr)
+	if err != nil {
+		return
+	}
+	if ip.IsLoopback() || ip.IsLinkLocalUnicast() {
+		return
+	}
+
+	if ip.To4() != nil {
+		endpoint.IPv4Address = cidr
+	} else if ip.To16() != nil {
+		endpoint.IPv6Address = cidr
+	}
+}
+
+// matchInterfaceToSubnets tries to match an interface to network subnets
+func matchInterfaceToSubnets(endpoint *EndpointResource, iface *native.NetInterface, subnets []*net.IPNet) bool {
+	for _, addr := range iface.Addrs {
+		ip, _, err := net.ParseCIDR(addr)
+		if err != nil || ip.IsLoopback() || ip.IsLinkLocalUnicast() {
+			continue
+		}
+
+		for _, subnet := range subnets {
+			if subnet.Contains(ip) {
+				endpoint.MacAddress = iface.HardwareAddr
+				setIPAddresses(endpoint, addr)
+				return true
+			}
+		}
+	}
+	return false
+}
+
+// populateEndpointFromNetNS finds and populates endpoint info from network namespace interfaces
+func populateEndpointFromNetNS(endpoint *EndpointResource, interfaces []native.NetInterface, subnets []*net.IPNet) {
+	for _, iface := range interfaces {
+		if !isUsableInterface(&iface) {
+			continue
+		}
+
+		if len(subnets) > 0 {
+			if matchInterfaceToSubnets(endpoint, &iface, subnets) {
+				return // Found matching interface
+			}
+			// Continue to next interface if this one doesn't match any subnets
+			continue
+		}
+
+		// Fallback: use first usable interface (for networks without explicit subnets)
+		endpoint.MacAddress = iface.HardwareAddr
+		for _, addr := range iface.Addrs {
+			setIPAddresses(endpoint, addr)
+		}
+		return
+	}
+}
+
 func NetworkFromNative(n *native.Network) (*Network, error) {
 	var res Network
 
@@ -973,15 +1055,20 @@ func NetworkFromNative(n *native.Network) (*Network, error) {
 		res.Labels = *n.NerdctlLabels
 	}
 
+	// Parse network subnets for interface matching
+	networkSubnets := parseNetworkSubnets(res.IPAM.Config)
+
 	res.Containers = make(map[string]EndpointResource)
 	for _, container := range n.Containers {
-		res.Containers[container.ID] = EndpointResource{
+		endpoint := EndpointResource{
 			Name: container.Labels[labels.Name],
-			// EndpointID:  container.EndpointID,
-			// MacAddress:  container.MacAddress,
-			// IPv4Address: container.IPv4Address,
-			// IPv6Address: container.IPv6Address,
 		}
+
+		if container.Process != nil && container.Process.NetNS != nil {
+			populateEndpointFromNetNS(&endpoint, container.Process.NetNS.Interfaces, networkSubnets)
+		}
+
+		res.Containers[container.ID] = endpoint
 	}
 
 	return &res, nil