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// Copyright 2015 CNI authors
//
// 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 main
import (
"encoding/binary"
"fmt"
"net"
"strconv"
"time"
"github.com/containernetworking/cni/pkg/types"
"github.com/d2g/dhcp4"
)
var optionNameToID = map[string]dhcp4.OptionCode{
"dhcp-client-identifier": dhcp4.OptionClientIdentifier,
"subnet-mask": dhcp4.OptionSubnetMask,
"routers": dhcp4.OptionRouter,
"host-name": dhcp4.OptionHostName,
"user-class": dhcp4.OptionUserClass,
"vendor-class-identifier": dhcp4.OptionVendorClassIdentifier,
}
func parseOptionName(option string) (dhcp4.OptionCode, error) {
if val, ok := optionNameToID[option]; ok {
return val, nil
}
i, err := strconv.ParseUint(option, 10, 8)
if err != nil {
return 0, fmt.Errorf("Can not parse option: %w", err)
}
return dhcp4.OptionCode(i), nil
}
func parseRouter(opts dhcp4.Options) net.IP {
if opts, ok := opts[dhcp4.OptionRouter]; ok {
if len(opts) == 4 {
return net.IP(opts)
}
}
return nil
}
func classfulSubnet(sn net.IP) net.IPNet {
return net.IPNet{
IP: sn,
Mask: sn.DefaultMask(),
}
}
func parseRoutes(opts dhcp4.Options) []*types.Route {
// StaticRoutes format: pairs of:
// Dest = 4 bytes; Classful IP subnet
// Router = 4 bytes; IP address of router
routes := []*types.Route{}
if opt, ok := opts[dhcp4.OptionStaticRoute]; ok {
for len(opt) >= 8 {
sn := opt[0:4]
r := opt[4:8]
rt := &types.Route{
Dst: classfulSubnet(sn),
GW: r,
}
routes = append(routes, rt)
opt = opt[8:]
}
}
return routes
}
func parseCIDRRoutes(opts dhcp4.Options) []*types.Route {
// See RFC4332 for format (http://tools.ietf.org/html/rfc3442)
routes := []*types.Route{}
if opt, ok := opts[dhcp4.OptionClasslessRouteFormat]; ok {
for len(opt) >= 5 {
width := int(opt[0])
if width > 32 {
// error: can't have more than /32
return nil
}
// network bits are compacted to avoid zeros
octets := 0
if width > 0 {
octets = (width-1)/8 + 1
}
if len(opt) < 1+octets+4 {
// error: too short
return nil
}
sn := make([]byte, 4)
copy(sn, opt[1:octets+1])
gw := net.IP(opt[octets+1 : octets+5])
rt := &types.Route{
Dst: net.IPNet{
IP: net.IP(sn),
Mask: net.CIDRMask(width, 32),
},
GW: gw,
}
routes = append(routes, rt)
opt = opt[octets+5:]
}
}
return routes
}
func parseSubnetMask(opts dhcp4.Options) net.IPMask {
mask, ok := opts[dhcp4.OptionSubnetMask]
if !ok {
return nil
}
return net.IPMask(mask)
}
func parseDuration(opts dhcp4.Options, code dhcp4.OptionCode, optName string) (time.Duration, error) {
val, ok := opts[code]
if !ok {
return 0, fmt.Errorf("option %v not found", optName)
}
if len(val) != 4 {
return 0, fmt.Errorf("option %v is not 4 bytes", optName)
}
secs := binary.BigEndian.Uint32(val)
return time.Duration(secs) * time.Second, nil
}
func parseLeaseTime(opts dhcp4.Options) (time.Duration, error) {
return parseDuration(opts, dhcp4.OptionIPAddressLeaseTime, "LeaseTime")
}
func parseRenewalTime(opts dhcp4.Options) (time.Duration, error) {
return parseDuration(opts, dhcp4.OptionRenewalTimeValue, "RenewalTime")
}
func parseRebindingTime(opts dhcp4.Options) (time.Duration, error) {
return parseDuration(opts, dhcp4.OptionRebindingTimeValue, "RebindingTime")
}
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