Add support for multiple CNI networks in podman inspect

When inspecting containers, info on CNI networks added to the
container by name (e.g. --net=name1) should be displayed
separately from the configuration of the default network, in a
separate map called Networks.

This patch adds this separation, improving our Docker
compatibility and also adding the ability to see if a container
has more than one IPv4 and IPv6 address and more than one MAC
address.

Fixes #4907

Signed-off-by: Matthew Heon <matthew.heon@pm.me>

3 files changed, 158 insertions, 64 deletions

diff --git a/libpod/container_inspect.go b/libpod/container_inspect.go
index 641bc8a91..a543a19c0 100644
--- a/libpod/container_inspect.go
+++ b/libpod/container_inspect.go
@@ -606,11 +606,45 @@ type InspectContainerState struct {
 	Healthcheck HealthCheckResults `json:"Healthcheck,omitempty"`
 }
 
+// InspectBasicNetworkConfig holds basic configuration information (e.g. IP
+// addresses, MAC address, subnet masks, etc) that are common for all networks
+// (both additional and main).
+type InspectBasicNetworkConfig struct {
+	// EndpointID is unused, maintained exclusively for compatibility.
+	EndpointID string `json:"EndpointID"`
+	// Gateway is the IP address of the gateway this network will use.
+	Gateway string `json:"Gateway"`
+	// IPAddress is the IP address for this network.
+	IPAddress string `json:"IPAddress"`
+	// IPPrefixLen is the length of the subnet mask of this network.
+	IPPrefixLen int `json:"IPPrefixLen"`
+	// SecondaryIPAddresses is a list of extra IP Addresses that the
+	// container has been assigned in this network.
+	SecondaryIPAddresses []string `json:"SecondaryIPAddresses,omitempty"`
+	// IPv6Gateway is the IPv6 gateway this network will use.
+	IPv6Gateway string `json:"IPv6Gateway"`
+	// GlobalIPv6Address is the global-scope IPv6 Address for this network.
+	GlobalIPv6Address string `json:"GlobalIPv6Address"`
+	// GlobalIPv6PrefixLen is the length of the subnet mask of this network.
+	GlobalIPv6PrefixLen int `json:"GlobalIPv6PrefixLen"`
+	// SecondaryIPv6Addresses is a list of extra IPv6 Addresses that the
+	// container has been assigned in this networ.
+	SecondaryIPv6Addresses []string `json:"SecondaryIPv6Addresses,omitempty"`
+	// MacAddress is the MAC address for the interface in this network.
+	MacAddress string `json:"MacAddress"`
+	// AdditionalMacAddresses is a set of additional MAC Addresses beyond
+	// the first. CNI may configure more than one interface for a single
+	// network, which can cause this.
+	AdditionalMacAddresses []string `json:"AdditionalMACAddresses,omitempty"`
+}
+
 // InspectNetworkSettings holds information about the network settings of the
 // container.
 // Many fields are maintained only for compatibility with `docker inspect` and
 // are unused within Libpod.
 type InspectNetworkSettings struct {
+	InspectBasicNetworkConfig
+
 	Bridge                 string               `json:"Bridge"`
 	SandboxID              string               `json:"SandboxID"`
 	HairpinMode            bool                 `json:"HairpinMode"`
@@ -618,16 +652,30 @@ type InspectNetworkSettings struct {
 	LinkLocalIPv6PrefixLen int                  `json:"LinkLocalIPv6PrefixLen"`
 	Ports                  []ocicni.PortMapping `json:"Ports"`
 	SandboxKey             string               `json:"SandboxKey"`
-	SecondaryIPAddresses   []string             `json:"SecondaryIPAddresses"`
-	SecondaryIPv6Addresses []string             `json:"SecondaryIPv6Addresses"`
-	EndpointID             string               `json:"EndpointID"`
-	Gateway                string               `json:"Gateway"`
-	GlobalIPv6Address      string               `json:"GlobalIPv6Address"`
-	GlobalIPv6PrefixLen    int                  `json:"GlobalIPv6PrefixLen"`
-	IPAddress              string               `json:"IPAddress"`
-	IPPrefixLen            int                  `json:"IPPrefixLen"`
-	IPv6Gateway            string               `json:"IPv6Gateway"`
-	MacAddress             string               `json:"MacAddress"`
+	// Networks contains information on non-default CNI networks this
+	// container has joined.
+	// It is a map of network name to network information.
+	Networks map[string]*InspectAdditionalNetwork `json:"Networks,omitempty"`
+}
+
+// InspectAdditionalNetwork holds information about non-default CNI networks the
+// container has been connected to.
+// As with InspectNetworkSettings, many fields are unused and maintained only
+// for compatibility with Docker.
+type InspectAdditionalNetwork struct {
+	InspectBasicNetworkConfig
+
+	// Name of the network we're connecting to.
+	NetworkID string `json:"NetworkID,omitempty"`
+	// DriverOpts is presently unused and maintained exclusively for
+	// compatibility.
+	DriverOpts map[string]string `json:"DriverOpts"`
+	// IPAMConfig is presently unused and maintained exlusively for
+	// compabitility.
+	IPAMConfig map[string]string `json:"IPAMConfig"`
+	// Links is presently unused and maintained exclusively for
+	// compatibility.
+	Links []string `json:"Links"`
 }
 
 // inspectLocked inspects a container for low-level information.
@@ -754,27 +802,7 @@ func (c *Container) getContainerInspectData(size bool, driverData *driver.Data)
 		GraphDriver:     driverData,
 		Mounts:          inspectMounts,
 		Dependencies:    c.Dependencies(),
-		NetworkSettings: &InspectNetworkSettings{
-			Bridge:                 "",    // TODO
-			SandboxID:              "",    // TODO - is this even relevant?
-			HairpinMode:            false, // TODO
-			LinkLocalIPv6Address:   "",    // TODO - do we even support IPv6?
-			LinkLocalIPv6PrefixLen: 0,     // TODO - do we even support IPv6?
-
-			Ports:                  []ocicni.PortMapping{}, // TODO - maybe worth it to put this in Docker format?
-			SandboxKey:             "",                     // Network namespace path
-			SecondaryIPAddresses:   nil,                    // TODO - do we support this?
-			SecondaryIPv6Addresses: nil,                    // TODO - do we support this?
-			EndpointID:             "",                     // TODO - is this even relevant?
-			Gateway:                "",                     // TODO
-			GlobalIPv6Address:      "",
-			GlobalIPv6PrefixLen:    0,
-			IPAddress:              "",
-			IPPrefixLen:            0,
-			IPv6Gateway:            "",
-			MacAddress:             "", // TODO
-		},
-		IsInfra: c.IsInfra(),
+		IsInfra:         c.IsInfra(),
 	}
 
 	if c.state.ConfigPath != "" {
@@ -792,13 +820,11 @@ func (c *Container) getContainerInspectData(size bool, driverData *driver.Data)
 		}
 	}
 
-	// Copy port mappings into network settings
-	if config.PortMappings != nil {
-		data.NetworkSettings.Ports = config.PortMappings
+	networkConfig, err := c.getContainerNetworkInfo()
+	if err != nil {
+		return nil, err
 	}
-
-	// Get information on the container's network namespace (if present)
-	data = c.getContainerNetworkInfo(data)
+	data.NetworkSettings = networkConfig
 
 	inspectConfig, err := c.generateInspectContainerConfig(ctrSpec)
 	if err != nil {
diff --git a/libpod/networking_linux.go b/libpod/networking_linux.go
index fa8593f20..d57b1a8eb 100644
--- a/libpod/networking_linux.go
+++ b/libpod/networking_linux.go
@@ -12,13 +12,13 @@ import (
 	"os"
 	"os/exec"
 	"path/filepath"
-	"strconv"
 	"strings"
 	"syscall"
 	"time"
 
 	cnitypes "github.com/containernetworking/cni/pkg/types/current"
 	"github.com/containernetworking/plugins/pkg/ns"
+	"github.com/containers/libpod/libpod/define"
 	"github.com/containers/libpod/pkg/errorhandling"
 	"github.com/containers/libpod/pkg/netns"
 	"github.com/containers/libpod/pkg/rootless"
@@ -556,37 +556,105 @@ func getContainerNetIO(ctr *Container) (*netlink.LinkStatistics, error) {
 	return netStats, err
 }
 
-func (c *Container) getContainerNetworkInfo(data *InspectContainerData) *InspectContainerData {
-	if c.state.NetNS != nil && len(c.state.NetworkStatus) > 0 {
-		// Report network settings from the first pod network
-		result := c.state.NetworkStatus[0]
-		// Go through our IP addresses
-		for _, ctrIP := range result.IPs {
-			ipWithMask := ctrIP.Address.String()
-			splitIP := strings.Split(ipWithMask, "/")
-			mask, _ := strconv.Atoi(splitIP[1])
-			if ctrIP.Version == "4" {
-				data.NetworkSettings.IPAddress = splitIP[0]
-				data.NetworkSettings.IPPrefixLen = mask
-				data.NetworkSettings.Gateway = ctrIP.Gateway.String()
-			} else {
-				data.NetworkSettings.GlobalIPv6Address = splitIP[0]
-				data.NetworkSettings.GlobalIPv6PrefixLen = mask
-				data.NetworkSettings.IPv6Gateway = ctrIP.Gateway.String()
+// Produce an InspectNetworkSettings containing information on the container
+// network.
+func (c *Container) getContainerNetworkInfo() (*InspectNetworkSettings, error) {
+	settings := new(InspectNetworkSettings)
+	settings.Ports = []ocicni.PortMapping{}
+	if c.config.PortMappings != nil {
+		// TODO: This may not be safe.
+		settings.Ports = c.config.PortMappings
+	}
+
+	// We can't do more if the network is down.
+	if c.state.NetNS == nil {
+		return settings, nil
+	}
+
+	// Set network namespace path
+	settings.SandboxKey = c.state.NetNS.Path()
+
+	// If this is empty, we're probably slirp4netns
+	if len(c.state.NetworkStatus) == 0 {
+		return settings, nil
+	}
+
+	// If we have CNI networks - handle that here
+	if len(c.config.Networks) > 0 {
+		if len(c.config.Networks) != len(c.state.NetworkStatus) {
+			return nil, errors.Wrapf(define.ErrInternal, "network inspection mismatch: asked to join %d CNI networks but have information on %d networks", len(c.config.Networks), len(c.state.NetworkStatus))
+		}
+
+		settings.Networks = make(map[string]*InspectAdditionalNetwork)
+
+		// CNI results should be in the same order as the list of
+		// networks we pass into CNI.
+		for index, name := range c.config.Networks {
+			cniResult := c.state.NetworkStatus[index]
+			addedNet := new(InspectAdditionalNetwork)
+			addedNet.NetworkID = name
+
+			basicConfig, err := resultToBasicNetworkConfig(cniResult)
+			if err != nil {
+				return nil, err
 			}
+			addedNet.InspectBasicNetworkConfig = basicConfig
+
+			settings.Networks[name] = addedNet
 		}
 
-		// Set network namespace path
-		data.NetworkSettings.SandboxKey = c.state.NetNS.Path()
+		return settings, nil
+	}
+
+	// If not joining networks, we should have at most 1 result
+	if len(c.state.NetworkStatus) > 1 {
+		return nil, errors.Wrapf(define.ErrInternal, "should have at most 1 CNI result if not joining networks, instead got %d", len(c.state.NetworkStatus))
+	}
+
+	if len(c.state.NetworkStatus) == 1 {
+		basicConfig, err := resultToBasicNetworkConfig(c.state.NetworkStatus[0])
+		if err != nil {
+			return nil, err
+		}
 
-		// Set MAC address of interface linked with network namespace path
-		for _, i := range result.Interfaces {
-			if i.Sandbox == data.NetworkSettings.SandboxKey {
-				data.NetworkSettings.MacAddress = i.Mac
+		settings.InspectBasicNetworkConfig = basicConfig
+	}
+
+	return settings, nil
+}
+
+// resultToBasicNetworkConfig produces an InspectBasicNetworkConfig from a CNI
+// result
+func resultToBasicNetworkConfig(result *cnitypes.Result) (InspectBasicNetworkConfig, error) {
+	config := InspectBasicNetworkConfig{}
+
+	for _, ctrIP := range result.IPs {
+		size, _ := ctrIP.Address.Mask.Size()
+		switch {
+		case ctrIP.Version == "4" && config.IPAddress == "":
+			config.IPAddress = ctrIP.Address.IP.String()
+			config.IPPrefixLen = size
+			config.Gateway = ctrIP.Gateway.String()
+			if ctrIP.Interface != nil && *ctrIP.Interface < len(result.Interfaces) && *ctrIP.Interface > 0 {
+				config.MacAddress = result.Interfaces[*ctrIP.Interface].Mac
+			}
+		case ctrIP.Version == "4" && config.IPAddress != "":
+			config.SecondaryIPAddresses = append(config.SecondaryIPAddresses, ctrIP.Address.String())
+			if ctrIP.Interface != nil && *ctrIP.Interface < len(result.Interfaces) && *ctrIP.Interface > 0 {
+				config.AdditionalMacAddresses = append(config.AdditionalMacAddresses, result.Interfaces[*ctrIP.Interface].Mac)
 			}
+		case ctrIP.Version == "6" && config.IPAddress == "":
+			config.GlobalIPv6Address = ctrIP.Address.IP.String()
+			config.GlobalIPv6PrefixLen = size
+			config.IPv6Gateway = ctrIP.Gateway.String()
+		case ctrIP.Version == "6" && config.IPAddress != "":
+			config.SecondaryIPv6Addresses = append(config.SecondaryIPv6Addresses, ctrIP.Address.String())
+		default:
+			return config, errors.Wrapf(define.ErrInternal, "unrecognized IP version %q", ctrIP.Version)
 		}
 	}
-	return data
+
+	return config, nil
 }
 
 type logrusDebugWriter struct {
diff --git a/libpod/networking_unsupported.go b/libpod/networking_unsupported.go
index d9b3730aa..7f343cf35 100644
--- a/libpod/networking_unsupported.go
+++ b/libpod/networking_unsupported.go
@@ -20,6 +20,6 @@ func (r *Runtime) createNetNS(ctr *Container) (err error) {
 	return define.ErrNotImplemented
 }
 
-func (c *Container) getContainerNetworkInfo(data *InspectContainerData) *InspectContainerData {
-	return nil
+func (c *Container) getContainerNetworkInfo() (*InspectNetworkSettings, error) {
+	return nil, define.ErrNotImplemented
 }