71 lines
2.3 KiB
Go
71 lines
2.3 KiB
Go
package dnsserver
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import (
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"fmt"
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"net"
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"strings"
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)
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type zoneAddr struct {
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Zone string
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Port string
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Transport string // dns, tls or grpc
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Address string // used for bound zoneAddr - validation of overlapping
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}
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// String returns the string representation of z.
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func (z zoneAddr) String() string {
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s := z.Transport + "://" + z.Zone + ":" + z.Port
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if z.Address != "" {
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s += " on " + z.Address
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}
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return s
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}
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// SplitProtocolHostPort splits a full formed address like "dns://[::1]:53" into parts.
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func SplitProtocolHostPort(address string) (protocol string, ip string, port string, err error) {
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parts := strings.Split(address, "://")
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switch len(parts) {
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case 1:
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ip, port, err := net.SplitHostPort(parts[0])
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return "", ip, port, err
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case 2:
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ip, port, err := net.SplitHostPort(parts[1])
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return parts[0], ip, port, err
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default:
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return "", "", "", fmt.Errorf("provided value is not in an address format : %s", address)
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}
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}
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type zoneOverlap struct {
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registeredAddr map[zoneAddr]zoneAddr // each zoneAddr is registered once by its key
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unboundOverlap map[zoneAddr]zoneAddr // the "no bind" equiv ZoneAddr is registered by its original key
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}
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func newOverlapZone() *zoneOverlap {
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return &zoneOverlap{registeredAddr: make(map[zoneAddr]zoneAddr), unboundOverlap: make(map[zoneAddr]zoneAddr)}
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}
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// registerAndCheck adds a new zoneAddr for validation, it returns information about existing or overlapping with already registered
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// we consider that an unbound address is overlapping all bound addresses for same zone, same port
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func (zo *zoneOverlap) registerAndCheck(z zoneAddr) (existingZone *zoneAddr, overlappingZone *zoneAddr) {
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if exist, ok := zo.registeredAddr[z]; ok {
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// exact same zone already registered
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return &exist, nil
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}
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uz := zoneAddr{Zone: z.Zone, Address: "", Port: z.Port, Transport: z.Transport}
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if already, ok := zo.unboundOverlap[uz]; ok {
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if z.Address == "" {
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// current is not bound to an address, but there is already another zone with a bind address registered
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return nil, &already
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}
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if _, ok := zo.registeredAddr[uz]; ok {
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// current zone is bound to an address, but there is already an overlapping zone+port with no bind address
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return nil, &uz
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}
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}
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// there is no overlap, keep the current zoneAddr for future checks
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zo.registeredAddr[z] = z
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zo.unboundOverlap[uz] = z
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return nil, nil
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}
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