dns_cache.h

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#ifndef _DNS_CACHE_H
#define _DNS_CACHE_H
 
//Dependencies
#include "core/net.h"
#include "core/socket.h"
 
//DNS tick interval
#ifndef DNS_TICK_INTERVAL
   #define DNS_TICK_INTERVAL 200
#elif (DNS_TICK_INTERVAL < 10)
   #error DNS_TICK_INTERVAL parameter is not valid
#endif
 
//Size of DNS cache
#ifndef DNS_CACHE_SIZE
   #define DNS_CACHE_SIZE 8
#elif (DNS_CACHE_SIZE < 1)
   #error DNS_CACHE_SIZE parameter is not valid
#endif
 
//Maximum length of domain names
#ifndef DNS_MAX_NAME_LEN
   #define DNS_MAX_NAME_LEN 63
#elif (DNS_MAX_NAME_LEN < 1)
   #error DNS_MAX_NAME_LEN parameter is not valid
#endif
 
//Initial polling interval
#ifndef DNS_CACHE_INIT_POLLING_INTERVAL
   #define DNS_CACHE_INIT_POLLING_INTERVAL 10
#elif (DNS_CACHE_INIT_POLLING_INTERVAL < 1)
   #error DNS_CACHE_INIT_POLLING_INTERVAL parameter is not valid
#endif
 
//Maximum polling interval
#ifndef DNS_CACHE_MAX_POLLING_INTERVAL
   #define DNS_CACHE_MAX_POLLING_INTERVAL 1000
#elif (DNS_CACHE_MAX_POLLING_INTERVAL < 10)
   #error DNS_CACHE_MAX_POLLING_INTERVAL parameter is not valid
#endif
 
//C++ guard
#ifdef __cplusplus
extern "C" {
#endif
 
 
typedef enum
{
   DNS_STATE_NONE        = 0,
   DNS_STATE_IN_PROGRESS = 1,
   DNS_STATE_RESOLVED    = 2,
   DNS_STATE_PERMANENT   = 3
} DnsState;
 
 
typedef struct
{
   DnsState state;                    
   HostType type;                     
   HostnameResolver protocol;         
   NetInterface *interface;           
   uint_t dnsServerIndex;             
   uint16_t port;                     
   uint16_t id;                       
   char_t name[DNS_MAX_NAME_LEN + 1]; 
   IpAddr ipAddr;                     
   systime_t timestamp;               
   systime_t timeout;                 
   systime_t maxTimeout;              
   uint_t retransmitCount;            
} DnsCacheEntry;
 
 
//Global variables
extern systime_t dnsTickCounter;
extern DnsCacheEntry dnsCache[DNS_CACHE_SIZE];
 
//DNS related functions
error_t dnsInit(void);
 
void dnsFlushCache(NetInterface *interface);
 
DnsCacheEntry *dnsCreateEntry(void);
void dnsDeleteEntry(DnsCacheEntry *entry);
 
DnsCacheEntry *dnsFindEntry(NetInterface *interface,
   const char_t *name, HostType type, HostnameResolver protocol);
 
void dnsTick(void);
 
//C++ guard
#ifdef __cplusplus
}
#endif
 
#endif