55 lines
899 B
Go
55 lines
899 B
Go
package rings
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import "net/netip"
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func PrefixToRange(subnet netip.Prefix) (from, to netip.Addr) {
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if u, ok := addrToU32(subnet.Addr()); ok {
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shift := 32 - subnet.Bits()
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m1 := uint32((1 << shift) - 1)
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m0 := uint32(0xffffffff) & ^m1
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u0 := u & m0
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u1 := u0 + m1
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from = u32ToAddr(u0)
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to = u32ToAddr(u1)
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}
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return from, to
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}
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func u32ToAddr(v uint32) netip.Addr {
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return addrFrom4(
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uint(v>>24)&0xff,
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uint(v>>16)&0xff,
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uint(v>>8)&0xff,
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uint(v)&0xff,
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)
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}
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func addrToU32(addr netip.Addr) (uint32, bool) {
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switch {
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case !addr.IsValid():
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return 0, false
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case addr.Is4(), addr.Is4In6():
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a4 := addr.As4()
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v := uint32(a4[0])<<24 +
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uint32(a4[1])<<16 +
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uint32(a4[2])<<8 +
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uint32(a4[3])
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return v, true
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default:
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return 0, false
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}
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}
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func addrFrom4(a, b, c, d uint) netip.Addr {
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return netip.AddrFrom4([4]byte{
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byte(a),
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byte(b),
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byte(c),
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byte(d),
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})
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}
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