pkg/ipam{,test}: improve error handling and tests

* _suite.go and _test.go file should be in the same package, using the
  _test package for that, which requires some fields and methods to be
  exported
* Introduce error type for cleaner error handling
* test adaptions for error type checking

diff --git a/ipam/ipam.go b/ipam/ipam.go
index 7777e6f..74f937d 100644 (file)
--- a/ipam/ipam.go
+++ b/ipam/ipam.go
@@ -30,7 +30,7 @@ import (
 
 const (
        // private mac prefix safe to use
-       privateMACPrefix = "0a:58"
+       PrivateMACPrefix = "0a:58"
 
        // veth link dev type
        vethLinkType = "veth"
@@ -58,7 +58,7 @@ func ConfigureIface(ifName string, res *types.Result) error {
 
        // only set hardware address to veth when using ipv4
        if link.Type() == vethLinkType && res.IP4 != nil {
-               hwAddr, err := generateHardwareAddr(res.IP4.IP.IP)
+               hwAddr, err := GenerateHardwareAddr4(res.IP4.IP.IP, PrivateMACPrefix)
                if err != nil {
                        return fmt.Errorf("failed to generate hardware addr: %v", err)
                }
@@ -89,20 +89,43 @@ func ConfigureIface(ifName string, res *types.Result) error {
        return nil
 }
 
-// generateHardwareAddr generates 48 bit virtual mac addresses based on the IP input.
-func generateHardwareAddr(ip net.IP) (net.HardwareAddr, error) {
-       if ip.To4() == nil {
-               return nil, fmt.Errorf("generateHardwareAddr only support valid ipv4 address as input")
+type SupportIp4OnlyErr struct{ msg string }
+
+func (e SupportIp4OnlyErr) Error() string { return e.msg }
+
+type MacParseErr struct{ msg string }
+
+func (e MacParseErr) Error() string { return e.msg }
+
+type InvalidPrefixLengthErr struct{ msg string }
+
+func (e InvalidPrefixLengthErr) Error() string { return e.msg }
+
+// GenerateHardwareAddr4 generates 48 bit virtual mac addresses based on the IP4 input.
+func GenerateHardwareAddr4(ip net.IP, prefix string) (net.HardwareAddr, error) {
+       switch {
+
+       case ip.To4() == nil:
+               return nil, SupportIp4OnlyErr{msg: "GenerateHardwareAddr4 only supports valid IPv4 address as input"}
+
+       case len(prefix) != len(PrivateMACPrefix):
+               return nil, InvalidPrefixLengthErr{msg: fmt.Sprintf(
+                       "Prefix has length %d instead  of %d", len(prefix), len(PrivateMACPrefix)),
+               }
        }
-       mac := privateMACPrefix
+
+       mac := prefix
        sections := strings.Split(ip.String(), ".")
        for _, s := range sections {
                i, _ := strconv.Atoi(s)
                mac = mac + ":" + fmt.Sprintf("%02x", i)
        }
+
        hwAddr, err := net.ParseMAC(mac)
        if err != nil {
-               return nil, fmt.Errorf("Failed to parse mac address %s generated based on ip %s due to: %v", mac, ip, err)
+               return nil, MacParseErr{msg: fmt.Sprintf(
+                       "Failed to parse mac address %q generated based on IP %q due to: %v", mac, ip, err),
+               }
        }
        return hwAddr, nil
 }

diff --git a/ipam/ipam_test.go b/ipam/ipam_test.go
index 0cacd08..1390cce 100644 (file)
--- a/ipam/ipam_test.go
+++ b/ipam/ipam_test.go
@@ -12,16 +12,18 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package ipam
+package ipam_test
 
 import (
        . "github.com/onsi/ginkgo"
        . "github.com/onsi/gomega"
        "net"
+
+       "github.com/containernetworking/cni/pkg/ipam"
 )
 
 var _ = Describe("ipam utils", func() {
-       Context("Generate Hardware Addrress", func() {
+       Context("Generate Hardware Address", func() {
                It("generate hardware address based on ipv4 address", func() {
                        testCases := []struct {
                                ip          net.IP
@@ -29,20 +31,20 @@ var _ = Describe("ipam utils", func() {
                        }{
                                {
                                        ip:          net.ParseIP("10.0.0.2"),
-                                       expectedMAC: privateMACPrefix + ":0a:00:00:02",
+                                       expectedMAC: ipam.PrivateMACPrefix + ":0a:00:00:02",
                                },
                                {
                                        ip:          net.ParseIP("10.250.0.244"),
-                                       expectedMAC: privateMACPrefix + ":0a:fa:00:f4",
+                                       expectedMAC: ipam.PrivateMACPrefix + ":0a:fa:00:f4",
                                },
                                {
                                        ip:          net.ParseIP("172.17.0.2"),
-                                       expectedMAC: privateMACPrefix + ":ac:11:00:02",
+                                       expectedMAC: ipam.PrivateMACPrefix + ":ac:11:00:02",
                                },
                        }
 
                        for _, tc := range testCases {
-                               mac, err := generateHardwareAddr(tc.ip)
+                               mac, err := ipam.GenerateHardwareAddr4(tc.ip, ipam.PrivateMACPrefix)
                                Expect(err).NotTo(HaveOccurred())
                                Expect(mac.String()).To(Equal(tc.expectedMAC))
                        }
@@ -54,9 +56,14 @@ var _ = Describe("ipam utils", func() {
                                net.ParseIP("2001:db8:0:1:1:1:1:1"),
                        }
                        for _, tc := range testCases {
-                               _, err := generateHardwareAddr(tc)
-                               Expect(err.Error()).To(Equal("generateHardwareAddr only support valid ipv4 address as input"))
+                               _, err := ipam.GenerateHardwareAddr4(tc, ipam.PrivateMACPrefix)
+                               Expect(err).To(BeAssignableToTypeOf(ipam.SupportIp4OnlyErr{}))
                        }
                })
+
+               It("return error if prefix is invalid", func() {
+                       _, err := ipam.GenerateHardwareAddr4(net.ParseIP("10.0.0.2"), "")
+                       Expect(err).To(BeAssignableToTypeOf(ipam.InvalidPrefixLengthErr{}))
+               })
        })
 })