dns.h

00001 /**
00002  * lwip DNS resolver header file.
00003 
00004  * Author: Jim Pettinato 
00005  *   April 2007
00006 
00007  * ported from uIP resolv.c Copyright (c) 2002-2003, Adam Dunkels.
00008  *
00009  * Redistribution and use in source and binary forms, with or without
00010  * modification, are permitted provided that the following conditions
00011  * are met:
00012  * 1. Redistributions of source code must retain the above copyright
00013  *    notice, this list of conditions and the following disclaimer.
00014  * 2. Redistributions in binary form must reproduce the above copyright
00015  *    notice, this list of conditions and the following disclaimer in the
00016  *    documentation and/or other materials provided with the distribution.
00017  * 3. The name of the author may not be used to endorse or promote
00018  *    products derived from this software without specific prior
00019  *    written permission.
00020  *
00021  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
00022  * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
00023  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
00024  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
00025  * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
00026  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
00027  * GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
00028  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
00029  * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
00030  * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
00031  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
00032  */
00033 
00034 #ifndef __LWIP_DNS_H__
00035 #define __LWIP_DNS_H__
00036 
00037 #include "lwip/opt.h"
00038 
00039 #if LWIP_DNS /* don't build if not configured for use in lwipopts.h */
00040 
00041 #include "lwip/err.h"
00042 
00043 #ifdef __cplusplus
00044 extern "C" {
00045 #endif
00046 
00047 /** DNS timer period */
00048 #define DNS_TMR_INTERVAL          1000
00049 
00050 /** DNS field TYPE used for "Resource Records" */
00051 #define DNS_RRTYPE_A              1     /* a host address */
00052 #define DNS_RRTYPE_NS             2     /* an authoritative name server */
00053 #define DNS_RRTYPE_MD             3     /* a mail destination (Obsolete - use MX) */
00054 #define DNS_RRTYPE_MF             4     /* a mail forwarder (Obsolete - use MX) */
00055 #define DNS_RRTYPE_CNAME          5     /* the canonical name for an alias */
00056 #define DNS_RRTYPE_SOA            6     /* marks the start of a zone of authority */
00057 #define DNS_RRTYPE_MB             7     /* a mailbox domain name (EXPERIMENTAL) */
00058 #define DNS_RRTYPE_MG             8     /* a mail group member (EXPERIMENTAL) */
00059 #define DNS_RRTYPE_MR             9     /* a mail rename domain name (EXPERIMENTAL) */
00060 #define DNS_RRTYPE_NULL           10    /* a null RR (EXPERIMENTAL) */
00061 #define DNS_RRTYPE_WKS            11    /* a well known service description */
00062 #define DNS_RRTYPE_PTR            12    /* a domain name pointer */
00063 #define DNS_RRTYPE_HINFO          13    /* host information */
00064 #define DNS_RRTYPE_MINFO          14    /* mailbox or mail list information */
00065 #define DNS_RRTYPE_MX             15    /* mail exchange */
00066 #define DNS_RRTYPE_TXT            16    /* text strings */
00067 
00068 /** DNS field CLASS used for "Resource Records" */
00069 #define DNS_RRCLASS_IN            1     /* the Internet */
00070 #define DNS_RRCLASS_CS            2     /* the CSNET class (Obsolete - used only for examples in some obsolete RFCs) */
00071 #define DNS_RRCLASS_CH            3     /* the CHAOS class */
00072 #define DNS_RRCLASS_HS            4     /* Hesiod [Dyer 87] */
00073 #define DNS_RRCLASS_FLUSH         0x800 /* Flush bit */
00074 
00075 /** Callback which is invoked when a hostname is found.
00076  * A function of this type must be implemented by the application using the DNS resolver.
00077  * @param name pointer to the name that was looked up.
00078  * @param ipaddr pointer to a struct ip_addr containing the IP address of the hostname,
00079  *        or NULL if the name could not be found (or on any other error).
00080  * @param callback_arg a user-specified callback argument passed to dns_gethostbyname
00081 */
00082 typedef void (*dns_found_callback)(const char *name, struct ip_addr *ipaddr, void *callback_arg);
00083 
00084 
00085 void           dns_init(void);
00086 
00087 void           dns_tmr(void);
00088 
00089 void           dns_setserver(u8_t numdns, struct ip_addr *dnsserver);
00090 
00091 struct ip_addr dns_getserver(u8_t numdns);
00092 
00093 err_t          dns_gethostbyname(const char *hostname, struct ip_addr *addr,
00094                                  dns_found_callback found, void *callback_arg);
00095 
00096 #if DNS_LOCAL_HOSTLIST && DNS_LOCAL_HOSTLIST_IS_DYNAMIC
00097 int            dns_local_removehost(const char *hostname, const struct ip_addr *addr);
00098 err_t          dns_local_addhost(const char *hostname, const struct ip_addr *addr);
00099 #endif /* DNS_LOCAL_HOSTLIST && DNS_LOCAL_HOSTLIST_IS_DYNAMIC */
00100 
00101 #ifdef __cplusplus
00102 };
00103 #endif
00104 
00105 #endif /* LWIP_DNS */
00106 
00107 #endif /* __LWIP_DNS_H__ */