Support CNI_ARGS in static IPAM plugin

This change is to add CNI_ARGS support in static IPAM plugin.
When IP/SUBNET/GATEWAY are given in CNI_ARGS, static IPAM adds
these info in addition to config files.

To configure ip address only from CNI_ARGS, 'address' field in config
is changed to optional from required.

plugins/ipam/static/README.md

@@ -38,8 +38,17 @@ static IPAM is very simple IPAM plugin that assigns IPv4 and IPv6 addresses stat
 ## Network configuration reference
 
 * `type` (string, required): "static"
-* `addresses` (array, required): an array of arrays of ip address objects:
+* `addresses` (array, optional): an array of arrays of ip address objects:
  * `address` (string, required): CIDR notation IP address.
  * `gateway` (string, optional): IP inside of "subnet" to designate as the gateway.
 * `routes` (string, optional): list of routes add to the container namespace. Each route is a dictionary with "dst" and optional "gw" fields. If "gw" is omitted, value of "gateway" will be used.
 * `dns` (string, optional): the dictionary with "nameservers", "domain" and "search".
+
+## Supported arguments
+The following [CNI_ARGS](https://github.com/containernetworking/cni/blob/master/SPEC.md#parameters) are supported:
+
+* `IP`: request a specific IP address from a subnet
+* `SUBNET`: request a specific subnet
+* `GATEWAY`: request a specific gateway address
+
+ (example: CNI_ARGS="IP=10.10.0.1;SUBNET=10.10.0.0/24;GATEWAY=10.10.0.254")

plugins/ipam/static/main.go

@@ -30,19 +30,29 @@ import (
 // The top-level network config - IPAM plugins are passed the full configuration
 // of the calling plugin, not just the IPAM section.
 type Net struct {
- Name string `json:"name"`
- CNIVersion string `json:"cniVersion"`
- IPAM *IPAMConfig `json:"ipam"`
+ Name string `json:"name"`
+ CNIVersion string `json:"cniVersion"`
+ IPAM *IPAMConfig `json:"ipam"`
+ RuntimeConfig struct {
+ Addresses []Address `json:"addresses,omitempty"`
+ } `json:"runtimeConfig,omitempty"`
 }
 
 type IPAMConfig struct {
  Name string
  Type string `json:"type"`
  Routes []*types.Route `json:"routes"`
- Addresses []Address `json:"addresses"`
+ Addresses []Address `json:"addresses,omitempty"`
  DNS types.DNS `json:"dns"`
 }
 
+type IPAMEnvArgs struct {
+ types.CommonArgs
+ IP net.IP `json:"ip,omitempty"`
+ SUBNET types.UnmarshallableString `json:"subnet,omitempty"`
+ GATEWAY net.IP `json:"gateway,omitempty"`
+}
+
 type Address struct {
  AddressStr string `json:"address"`
  Gateway net.IP `json:"gateway,omitempty"`
@@ -77,9 +87,14 @@ func LoadIPAMConfig(bytes []byte, envArgs string) (*IPAMConfig, string, error) {
  return nil, "", fmt.Errorf("IPAM config missing 'ipam' key")
  }
 
+ if len(n.RuntimeConfig.Addresses) != 0 {
+ n.IPAM.Addresses = append(n.RuntimeConfig.Addresses, n.IPAM.Addresses...)
+ }
+
  // Validate all ranges
  numV4 := 0
  numV6 := 0
+
  for i := range n.IPAM.Addresses {
  ip, addr, err := net.ParseCIDR(n.IPAM.Addresses[i].AddressStr)
  if err != nil {
@@ -101,6 +116,34 @@ func LoadIPAMConfig(bytes []byte, envArgs string) (*IPAMConfig, string, error) {
  }
  }
 
+ if envArgs != "" {
+ e := IPAMEnvArgs{}
+ err := types.LoadArgs(envArgs, &e)
+ if err != nil {
+ return nil, "", err
+ }
+
+ if e.IP != nil && e.SUBNET != "" {
+ _, subnet, err := net.ParseCIDR(string(e.SUBNET))
+ if err != nil {
+ return nil, "", fmt.Errorf("invalid CIDR %s: %s", e.SUBNET, err)
+ }
+
+ addr := Address{Address: net.IPNet{IP: e.IP, Mask: subnet.Mask}}
+ if e.GATEWAY != nil {
+ addr.Gateway = e.GATEWAY
+ }
+ if addr.Address.IP.To4() != nil {
+ addr.Version = "4"
+ numV4++
+ } else {
+ addr.Version = "6"
+ numV6++
+ }
+ n.IPAM.Addresses = append(n.IPAM.Addresses, addr)
+ }
+ }
+
  // CNI spec 0.2.0 and below supported only one v4 and v6 address
  if numV4 > 1 || numV6 > 1 {
  for _, v := range types020.SupportedVersions {

plugins/ipam/static/static_test.go

@@ -148,6 +148,68 @@ var _ = Describe("static Operations", func() {
  })
  Expect(err).NotTo(HaveOccurred())
  })
+
+ It("allocates and releases addresses with ADD/DEL, with ENV variables", func() {
+ const ifname string = "eth0"
+ const nspath string = "/some/where"
+
+ conf := `{
+ "cniVersion": "0.3.1",
+ "name": "mynet",
+ "type": "ipvlan",
+ "master": "foo0",
+ "ipam": {
+ "type": "static",
+ "routes": [
+ { "dst": "0.0.0.0/0" },
+ { "dst": "192.168.0.0/16", "gw": "10.10.5.1" }],
+ "dns": {
+ "nameservers" : ["8.8.8.8"],
+ "domain": "example.com",
+ "search": [ "example.com" ]
+ }
+ }
+ }`
+
+ args := &skel.CmdArgs{
+ ContainerID: "dummy",
+ Netns: nspath,
+ IfName: ifname,
+ StdinData: []byte(conf),
+ Args: "IP=10.10.0.1;SUBNET=10.10.0.0/24;GATEWAY=10.10.0.254",
+ }
+
+ // Allocate the IP
+ r, raw, err := testutils.CmdAddWithArgs(args, func() error {
+ return cmdAdd(args)
+ })
+ Expect(err).NotTo(HaveOccurred())
+ Expect(strings.Index(string(raw), "\"version\":")).Should(BeNumerically(">", 0))
+
+ result, err := current.GetResult(r)
+ Expect(err).NotTo(HaveOccurred())
+
+ // Gomega is cranky about slices with different caps
+ Expect(*result.IPs[0]).To(Equal(
+ current.IPConfig{
+ Version: "4",
+ Address: mustCIDR("10.10.0.1/24"),
+ Gateway: net.ParseIP("10.10.0.254"),
+ }))
+
+ Expect(len(result.IPs)).To(Equal(1))
+
+ Expect(result.Routes).To(Equal([]*types.Route{
+ {Dst: mustCIDR("0.0.0.0/0")},
+ {Dst: mustCIDR("192.168.0.0/16"), GW: net.ParseIP("10.10.5.1")},
+ }))
+
+ // Release the IP
+ err = testutils.CmdDelWithArgs(args, func() error {
+ return cmdDel(args)
+ })
+ Expect(err).NotTo(HaveOccurred())
+ })
 })
 
 func mustCIDR(s string) net.IPNet {