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52 lines
1.4 KiB
52 lines
1.4 KiB
6 months ago
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package rings
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import "net/netip"
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// RingOnePrefix represents a (virtual) local network of a zone.
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//
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// Ring 1 is `10.(region_id).(zone_id << 4).(node_id)/20` network
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// grouped under what would be Ring 2 for region_id 0.
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// There are 12 bits worth of nodes but nodes under 255 are special
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// as they also get a slot on Ring 0.
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func RingOnePrefix(region RegionID, zone ZoneID) (cidr netip.Prefix, err error) {
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switch {
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case !region.Valid():
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err = ErrOutOfRange(region, "region")
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case !zone.Valid():
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err = ErrOutOfRange(zone, "zone")
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default:
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addr := unsafeRingOneAddress(region, zone, 0)
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cidr = netip.PrefixFrom(addr, RingOneBits)
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}
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return cidr, err
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}
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// RingOneAddress returns a Ring 1 address for a particular node.
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//
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// A ring 1 address is `10.(region_id).(zone_id << 4).(node_id)/20`
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// but the node_id can take up to 12 bits.
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func RingOneAddress(region RegionID, zone ZoneID, node NodeID) (addr netip.Addr, err error) {
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switch {
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case !region.Valid():
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err = ErrOutOfRange(region, "region")
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case !zone.Valid():
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err = ErrOutOfRange(zone, "zone")
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case !node.Valid():
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err = ErrOutOfRange(node, "node")
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default:
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addr = unsafeRingOneAddress(region, zone, node)
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}
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return addr, err
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}
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func unsafeRingOneAddress(region RegionID, zone ZoneID, node NodeID) netip.Addr {
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r := uint(region)
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z := uint(zone)
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n := uint(node)
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n1 := n >> 8
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n0 := n >> 0
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return AddrFrom4(10, r, z<<4+n1, n0)
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}
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