59 lines
1.6 KiB
Go
59 lines
1.6 KiB
Go
package dhcp4
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import (
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"encoding/binary"
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"net"
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"time"
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)
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// IPRange returns how many ips in the ip range from start to stop (inclusive)
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func IPRange(start, stop net.IP) int {
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//return int(Uint([]byte(stop))-Uint([]byte(start))) + 1
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return int(binary.BigEndian.Uint32(stop.To4())) - int(binary.BigEndian.Uint32(start.To4())) + 1
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}
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// IPAdd returns a copy of start + add.
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// IPAdd(net.IP{192,168,1,1},30) returns net.IP{192.168.1.31}
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func IPAdd(start net.IP, add int) net.IP { // IPv4 only
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start = start.To4()
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//v := Uvarint([]byte(start))
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result := make(net.IP, 4)
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binary.BigEndian.PutUint32(result, binary.BigEndian.Uint32(start)+uint32(add))
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//PutUint([]byte(result), v+uint64(add))
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return result
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}
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// IPLess returns where IP a is less than IP b.
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func IPLess(a, b net.IP) bool {
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b = b.To4()
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for i, ai := range a.To4() {
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if ai != b[i] {
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return ai < b[i]
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}
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}
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return false
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}
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// IPInRange returns true if ip is between (inclusive) start and stop.
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func IPInRange(start, stop, ip net.IP) bool {
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return !(IPLess(ip, start) || IPLess(stop, ip))
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}
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// OptionsLeaseTime - converts a time.Duration to a 4 byte slice, compatible
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// with OptionIPAddressLeaseTime.
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func OptionsLeaseTime(d time.Duration) []byte {
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leaseBytes := make([]byte, 4)
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binary.BigEndian.PutUint32(leaseBytes, uint32(d/time.Second))
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//PutUvarint(leaseBytes, uint64(d/time.Second))
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return leaseBytes
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}
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// JoinIPs returns a byte slice of IP addresses, one immediately after the other
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// This may be useful for creating multiple IP options such as OptionRouter.
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func JoinIPs(ips []net.IP) (b []byte) {
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for _, v := range ips {
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b = append(b, v.To4()...)
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}
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return
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}
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