37 lines
586 B
Go
37 lines
586 B
Go
package dhcpd
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import (
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"encoding/binary"
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"fmt"
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"net"
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)
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func tryTo4(ip net.IP) (ip4 net.IP, err error) {
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if ip == nil {
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return nil, fmt.Errorf("%v is not an IP address", ip)
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}
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ip4 = ip.To4()
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if ip4 == nil {
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return nil, fmt.Errorf("%v is not an IPv4 address", ip)
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}
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return ip4, nil
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}
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// Return TRUE if subnet mask is correct (e.g. 255.255.255.0)
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func isValidSubnetMask(mask net.IP) bool {
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var n uint32
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n = binary.BigEndian.Uint32(mask)
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for i := 0; i != 32; i++ {
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if n == 0 {
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break
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}
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if (n & 0x80000000) == 0 {
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return false
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}
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n <<= 1
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}
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return true
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}
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