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>C.5. Read/write master-capable backends</A
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><P
> In order to be a useful master for a domain, notifies must be sent out whenever a domain is changed. Periodically, PDNS
queries backends for domains that may have changed, and sends out notifications for slave nameservers.
</P
><P
> In order to do so, PDNS calls the <CODE
CLASS="FUNCTION"
>getUpdatedMasters()</CODE
> method. Like the <CODE
CLASS="FUNCTION"
>getUnfreshSlaveInfos()</CODE
>
function mentioned above, this should add changed domain names to the vector passed.
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> The following excerpt from the DNSBackend shows the relevant functions:
</P
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> <PRE
CLASS="PROGRAMLISTING"
> class DNSBackend {
public:
/* ... */
virtual void getUpdatedMasters(vector<DomainInfo>* domains);
virtual void setNotifed(int id, u_int32_t serial);
/* ... */
}
</PRE
>
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><P
> These functions all have a default implementation that returns false - which explains that these methods can be omitted in simple backends.
Furthermore, unlike with simple backends, a slave capable backend must make sure that the 'DNSBackend *db' field of the SOAData record is filled
out correctly - it is used to determine which backend will house this zone.
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>void getUpdatedMasters(vector<DomainInfo>* domains)</DT
><DD
><P
> When called, the backend should examine its list of master domains and add any changed ones to the DomainInfo vector
</P
></DD
><DT
>bool setNotified(int domain_id, u_int32_t serial)</DT
><DD
><P
> Indicate that notifications have been queued for this domain and that it need not be considered 'updated' anymore
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