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names.go
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names.go
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// Copyright (c) 2017 Tigera, Inc. All rights reserved.
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package resources
import (
"fmt"
"strings"
"github.com/projectcalico/libcalico-go/lib/net"
log "github.com/sirupsen/logrus"
)
// This file contains various name conversion methods that can be used to convert
// between Calico key types and resource names.
// IPToResourceName converts an IP address to a name used for a k8s resource.
func IPToResourceName(ip net.IP) string {
name := ""
if ip.To4() != nil {
name = strings.Replace(ip.String(), ".", "-", 3)
} else {
// IPv6 address can end in a "::" which would be a string ending in "--",
// which is not allowed in k8s name field, so we expand the IPv6 address and then replace ":" with "-".
// fe08:123:445:: will look like fe08-0123-0445-0000-0000-0000-0000-0000
ip6 := ip.To16()
bytes := []string{}
// Go through pairs of bytes in the address and convert them to a hex string.
for i := 0; i < len(ip6); i += 2 {
bytes = append(bytes, fmt.Sprintf("%.2x%.2x", ip6[i], ip6[i+1]))
}
// Combine them all into a name.
name = strings.Join(bytes, "-")
}
log.WithFields(log.Fields{
"Name": name,
"IP": ip.String(),
}).Debug("Converting IP to resource name")
return name
}
// ResourceNameToIP converts a name used for a k8s resource to an IP address.
func ResourceNameToIP(name string) (*net.IP, error) {
ip := net.ParseIP(resourceNameToIPString(name))
if ip == nil {
return nil, fmt.Errorf("invalid resource name %s: does not follow Calico IP name format", name)
}
return ip, nil
}
// resourceNameToIPString converts a name used for a k8s resource to an IP address string.
// This function does not check the validity of the result - it merely reverses the
// character conversion used to convert an IP address to a k8s compatible name.
func resourceNameToIPString(name string) string {
// The IP address is stored in the name with periods and colons replaced
// by dashes. To determine if this is IPv4 or IPv6 count the dashes. If
// either of the following are true, it's IPv6:
// - There is a "--"
// - The number of "-" is greater than 3.
var ipstr string
if strings.Contains(name, "--") || strings.Count(name, "-") > 3 {
// IPv6: replace - with :
ipstr = strings.Replace(name, "-", ":", 7)
} else {
// IPv4: replace - with .
ipstr = strings.Replace(name, "-", ".", 3)
}
log.WithFields(log.Fields{
"Name": name,
"IP": ipstr,
}).Debug("Converting resource name to IP String")
return ipstr
}