pkg: add a function to generate chain names

Adds a function to generate chain names for use in iptables and
ports all drivers to use that function. Also adds tests for the
said function.

diff --git a/pkg/utils/utils.go b/pkg/utils/utils.go
new file mode 100644 (file)
index 0000000..eaf48d0
--- /dev/null
+++ b/pkg/utils/utils.go
@@ -0,0 +1,20 @@
+package utils
+
+import (
+       "crypto/sha512"
+       "fmt"
+)
+
+// 29 - len('CNI') - 2*len('-')
+const maxNameLen = 16
+
+// Generates a chain name to be used with iptables.
+// Ensures that the generated name is less than
+// 29 chars in length
+func FormatChainName(name string, id string) string {
+       h := sha512.Sum512([]byte(id))
+       if len(name) > maxNameLen {
+               return fmt.Sprintf("CNI-%s-%x", name[:len(name)-maxNameLen], h[:8])
+       }
+       return fmt.Sprintf("CNI-%s-%x", name, h[:8])
+}

diff --git a/pkg/utils/utils_suite_test.go b/pkg/utils/utils_suite_test.go
new file mode 100644 (file)
index 0000000..f160db6
--- /dev/null
+++ b/pkg/utils/utils_suite_test.go
@@ -0,0 +1,13 @@
+package utils_test
+
+import (
+       . "github.com/onsi/ginkgo"
+       . "github.com/onsi/gomega"
+
+       "testing"
+)
+
+func TestUtils(t *testing.T) {
+       RegisterFailHandler(Fail)
+       RunSpecs(t, "Utils Suite")
+}

diff --git a/pkg/utils/utils_test.go b/pkg/utils/utils_test.go
new file mode 100644 (file)
index 0000000..e9b9f9b
--- /dev/null
+++ b/pkg/utils/utils_test.go
@@ -0,0 +1,18 @@
+package utils
+
+import (
+       . "github.com/onsi/ginkgo"
+       . "github.com/onsi/gomega"
+)
+
+var _ = Describe("Utils", func() {
+       It("should format a short name", func() {
+               chain := FormatChainName("test", "1234")
+               Expect(chain).To(Equal("CNI-test-d404559f602eab6f"))
+       })
+
+       It("should truncate a long name", func() {
+               chain := FormatChainName("testalongnamethatdoesnotmakesense", "1234")
+               Expect(chain).To(Equal("CNI-testalongnamethat-d404559f602eab6f"))
+       })
+})

diff --git a/plugins/main/bridge/bridge.go b/plugins/main/bridge/bridge.go
index 49c0aa5..d5581bf 100644 (file)
--- a/plugins/main/bridge/bridge.go
+++ b/plugins/main/bridge/bridge.go
@@ -28,6 +28,7 @@ import (
        "github.com/appc/cni/pkg/ns"
        "github.com/appc/cni/pkg/skel"
        "github.com/appc/cni/pkg/types"
+       "github.com/appc/cni/pkg/utils"
        "github.com/vishvananda/netlink"
 )
 
@@ -220,7 +221,7 @@ func cmdAdd(args *skel.CmdArgs) error {
        }
 
        if n.IPMasq {
-               chain := "CNI-" + n.Name
+               chain := utils.FormatChainName(n.Name, args.ContainerID)
                if err = ip.SetupIPMasq(ip.Network(&result.IP4.IP), chain); err != nil {
                        return err
                }

diff --git a/plugins/main/ptp/ptp.go b/plugins/main/ptp/ptp.go
index 3cb8f64..b397b79 100644 (file)
--- a/plugins/main/ptp/ptp.go
+++ b/plugins/main/ptp/ptp.go
@@ -15,7 +15,6 @@
 package main
 
 import (
-       "crypto/sha512"
        "encoding/json"
        "errors"
        "fmt"
@@ -30,6 +29,7 @@ import (
        "github.com/appc/cni/pkg/ns"
        "github.com/appc/cni/pkg/skel"
        "github.com/appc/cni/pkg/types"
+       "github.com/appc/cni/pkg/utils"
 )
 
 func init() {
@@ -178,8 +178,7 @@ func cmdAdd(args *skel.CmdArgs) error {
        }
 
        if conf.IPMasq {
-               h := sha512.Sum512([]byte(args.ContainerID))
-               chain := fmt.Sprintf("CNI-%s-%x", conf.Name, h[:8])
+               chain := utils.FormatChainName(conf.Name, args.ContainerID)
                if err = ip.SetupIPMasq(&result.IP4.IP, chain); err != nil {
                        return err
                }
@@ -206,8 +205,7 @@ func cmdDel(args *skel.CmdArgs) error {
        }
 
        if conf.IPMasq {
-               h := sha512.Sum512([]byte(args.ContainerID))
-               chain := fmt.Sprintf("CNI-%s-%x", conf.Name, h[:8])
+               chain := utils.FormatChainName(conf.Name, args.ContainerID)
                if err = ip.TeardownIPMasq(ipn, chain); err != nil {
                        return err
                }

diff --git a/test b/test
index a333086..a51a0e8 100755 (executable)
--- a/test
+++ b/test
@@ -11,7 +11,7 @@ set -e
 
 source ./build
 
-TESTABLE="plugins/ipam/dhcp plugins/main/loopback pkg/invoke pkg/ns pkg/skel pkg/types"
+TESTABLE="plugins/ipam/dhcp plugins/main/loopback pkg/invoke pkg/ns pkg/skel pkg/types pkg/utils"
 FORMATTABLE="$TESTABLE libcni pkg/ip pkg/ns pkg/types pkg/ipam plugins/ipam/host-local plugins/main/bridge plugins/meta/flannel plugins/meta/tuning"
 
 # user has not provided PKG override