Contents:

Overview








:

DNS module.
Features:
- DNS server for resolving names and publication domain
- Names and records resolving
- Cashing
- It is DLL.

Usage




This is DNS server.
It may work thought UDP and TCP protocol. Usually for UDP using name resolving, but for long size requests, (e.g. AXFR -- download full zone) using TCP. For setup server call SetUDPServer, SetTCPServer. The callback function will call when somebody
when somebody required anything from server.
The host program may just return zero by this callback, and in this case the server will work with this request (make reply if
the host defined, or make recursive request if recursion enable).
The host program may return the error code, and in this case request will be declined.
The host program may make reply with help SRVAddReplyRecord , SRVAddARecord, SRVAddAAAARecord, SRVAddPTRRecordm
SRVAddMXRecord, SRVAddNSRecord, SRVAddSOARecord, SRVAddSOARecord functions, and then call SRVSendReply, to send it

Functios









type of stream
typedef void * ServerStream;



DNSReqCallback
type for callback function that will call for each request, after request recived, before server do anything other.
typedef int (* DNSReqCallback)(ServerStream * stream, char * reqname, int action, ...);
Parameters:
The stream may be used by host program for next request.
The reqname it is name of requested file.
The action defined there: ACTION_REQ_A ACTION_REQ_PTR ACTION_REQ_CNAME ACTION_REQ_MX ACTION_REQ_NS ACTION_REQ_AAAA ACTION_REQ_ANY ACTION_REQ_SOA ACTION_REQ_TXT ACTION_REQ_AXFR ACTION_REQ_UNKNOW
ACTION_REQ_TCP

Return value:
If this callback return zero, the server will still work the request.
If this callback return subzero the server understand that host program
If this callback return value above zero, the server return it to client as error code and return error page.

ALL_ACTIONS


SetUDPServer
The host program must only call SetServer function, that create server thread
int SetUDPServer(DNSReqCallback callback=NULL, int mask=ALL_ACTIONS);
Parameters:
The callback -- callback function that will call for each request, after request received, before server do anything other
by default NULL -- int this case the server will just work with request.
The port -- TCP/IP port. If used default value zero, the server use value from config, by default 21.
mask -- the mask for action for that the server call callback
Return value:
Zero if sucess.
Subzero if fail


SetTCPServer
The host program must only call SetServer function, that create server thread
int SetTCPServer(DNSReqCallback callback=NULL, int mask=ALL_ACTIONS);
Parameters:
The callback -- callback function that will call for each request, after request recived, before server do anything other
by default NULL -- int this case the server will just work with request.
The port -- TCP/IP port. If used default value zero, the server use value from config, by default 21.
mask -- the mask for action for that the server call callback
Return value:
Zero if success.
Subzero if fail


PART_REQUEST PART_REPLY PART_ADV


SRVAddReplyRecord
The host program may send data to the client CONTROL connection with next functions:
int SRVAddReplyRecord(ServerStream * stream, void * bufer, int type, int part);
Parameters:
The stream -- pointer to stream that was transfer to callback function.
The buffer -- buffer to send
The type -- type of reply
The part -- part of reply
Return value:
Number of bytes in the reply.
Zero if error


SRVAddARecord
The host program may send data to the client CONTROL connection with next functions:
int SRVAddARecord(ServerStream * stream, ulong IP, char * host=0, int part=0);
Parameters:
The stream -- pointer to stream that was transfer to callback function.
IP -- is IP address for reply
host -- is the source host, the default NULL pointer mean that IP for required host
The part -- part of reply
Return value:
Number of bytes in the reply.
Zero if error
SRVAddAAAARecord

int SRVAddAAAARecord(ServerStream * stream, uchar* IPv6, char * host=0, int part=0);
Parameters:
The stream -- pointer to stream that was transfer to callback function.
IPv6 -- is IPv6 address for reply
host -- is the source host, the default NULL pointer mean that IP for required host
The part -- part of reply
Return value:
Number of bytes in the reply.
Zero if error

SRVAddMXRecord
The host program may send data to the client CONTROL connection with next functions:
int SRVAddMXRecord(ServerStream * stream, char * mhost, int priority, char * host=0, int part=0);
Parameters:
The stream -- pointer to stream that was transfer to callback function.
mhost -- is mail host for reply
priority -- is mail host priority
host -- is the source host, the default NULL pointer mean that for required host
The part -- part of reply
Return value:
Number of bytes in the reply.
Zero if error

SRVAddNSRecord
The host program may send data to the client CONTROL connection with next functions:
int SRVAddNSRecord(ServerStream * stream, char * ns, char * host=0, int part=0);
Parameters:
The stream -- pointer to stream that was transfer to callback function.
ns -- is names server for reply
host -- is the source host, the default NULL pointer mean that for required host
The part -- part of reply
Return value:
Number of bytes in the reply.
Zero if error


SRVAddCNAMERecord
The host program may send data to the client CONTROL connection with next functions:
int SRVAddCNAMERecord(ServerStream * stream, char * cname, char * host=0, int part=0);
Parameters:
The stream -- pointer to stream that was transfer to callback function.
cname -- is alternate name for reply
host -- is the source host, the default NULL pointer mean that for required host
The part -- part of reply
Return value:
Number of bytes in the reply.
Zero if error
SRVAddTEXTERecord

int SRVAddTEXTERecord(ServerStream * stream, char * text, char * host=0, int part=0);
Parameters:
The stream -- pointer to stream that was transfer to callback function.
text -- is text for reply
host -- is the source host, the default NULL pointer mean that for required host
The part -- part of reply
Return value:
Number of bytes in the reply.
Zero if error



The host program may send data to the client CONTROL connection with next functions:
int SRVAddSOARecord(ServerStream *stream,char *mname,
char *rname,char *serial,char *refres, char *retry,
char *expire,char *minimum,
char *host=0);
Parameters:
The stream -- pointer to stream that was transfer to callback function.
ns -- is names server for reply
mname -- The of the name server that was the
original or primary source of data for this zone.
rname -- A which specifies the mailbox of the
person responsible for this zone.
serial -- The unsigned 32 bit version number of the original copy
of the zone. Zone transfers preserve this value. This
value wraps and should be compared using sequence space
arithmetic.
refresh -- A 32 bit time interval before the zone should be
refreshed .
retry -- A 32 bit time interval that should elapse before a
failed refresh should be retried.
expire -- A 32 bit time value that specifies the upper limit on
the time interval that can elapse before the zone is no
longer authoritative.
minimum -- The unsigned 32 bit minimum TTL field that should be
exported with any RR from this zone.
Return value:
Number of bytes in the reply.
Zero if error


SRVAddPTRRecord
The host program may send data to the client CONTROL connection with next functions:
int SRVAddPTRRecord(ServerStream * stream, char * ptr, char * host=0, int part=0);
Parameters:
The stream -- pointer to stream that was transfer to callback function.
ns -- is names server for reply
host -- is the source host, the default NULL pointer mean that IP for required host
The part -- part of reply
Return value:
Number of bytes in the reply.
Zero if error


SRVSendReply
The host program may send data to the client DATA conection with next functions:
int SRVSendReply(ServerStream * stream);
Parameters:
The stream -- pointer to stream that was transfer to callback function.
Return value:
Number of bytes that has been send.
Zero if error







GetRemoteIP
Advanced info about connection you may get with next functions.
ulong GetRemoteIP(ServerStream * stream);
Parameters:
The stream -- pointer to stream that was transfer to callback function.
Return value:
IP address of remote.

GetRemoteAddr

int GetRemoteAddr(void * addr, int buflen);
Parameters:
The stream -- pointer to stream that was transfer to callback function.
Return value:
address of remote in sockaddr struct
GetSocket

int GetSocket(ServerStream * stream);
Parameters:
The stream -- pointer to stream that was transfer to callback function.
Return value:
socket


The host program may load all params for module from separate file,
LoadConfig
or my set required params directly, or use default values.
int LoadConfig(char * filename="ftp.cfg");
Parameters:
The filename -- name of configuration file.
Return value:
Zero if success.
Subzero if fail


SetConfigParam
You may set all params directly:
void SetConfigParam(char * param, int val);
Parameters:
The param -- name of param
val -- value.
SetConfigParam

void SetConfigParam(char * param, char * val);
Parameters:
The param -- name of param
val -- value.

To get current values of configuration params you may use next functions:
GetConfigParamInt
For integer params:
int GetConfigParamInt(char * param);
Parameters:
The param -- name of param

SetConfigParamStr
For string params:
char *SetConfigParamStr(char * param);
Parameters:
The param -- name of param