/** * lwip DNS resolver header file. * Author: Jim Pettinato  *   April 2007 * ported from uIP resolv.c Copyright (c) 2002-2003, Adam Dunkels. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright *    notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright *    notice, this list of conditions and the following disclaimer in the *    documentation and/or other materials provided with the distribution. * 3. The name of the author may not be used to endorse or promote *    products derived from this software without specific prior *    written permission. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE * GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */#ifndef __LWIP_DNS_H__#define __LWIP_DNS_H__#include "lwip/opt.h"#if LWIP_DNS /* don't build if not configured for use in lwipopts.h *//** DNS timer period */#define DNS_TMR_INTERVAL          1000/** DNS field TYPE used for "Resource Records" */#define DNS_RRTYPE_A              1     /* a host address */#define DNS_RRTYPE_NS             2     /* an authoritative name server */#define DNS_RRTYPE_MD             3     /* a mail destination (Obsolete - use MX) */#define DNS_RRTYPE_MF             4     /* a mail forwarder (Obsolete - use MX) */#define DNS_RRTYPE_CNAME          5     /* the canonical name for an alias */#define DNS_RRTYPE_SOA            6     /* marks the start of a zone of authority */#define DNS_RRTYPE_MB             7     /* a mailbox domain name (EXPERIMENTAL) */#define DNS_RRTYPE_MG             8     /* a mail group member (EXPERIMENTAL) */#define DNS_RRTYPE_MR             9     /* a mail rename domain name (EXPERIMENTAL) */#define DNS_RRTYPE_NULL           10    /* a null RR (EXPERIMENTAL) */#define DNS_RRTYPE_WKS            11    /* a well known service description */#define DNS_RRTYPE_PTR            12    /* a domain name pointer */#define DNS_RRTYPE_HINFO          13    /* host information */#define DNS_RRTYPE_MINFO          14    /* mailbox or mail list information */#define DNS_RRTYPE_MX             15    /* mail exchange */#define DNS_RRTYPE_TXT            16    /* text strings *//** DNS field CLASS used for "Resource Records" */#define DNS_RRCLASS_IN            1     /* the Internet */#define DNS_RRCLASS_CS            2     /* the CSNET class (Obsolete - used only for examples in some obsolete RFCs) */#define DNS_RRCLASS_CH            3     /* the CHAOS class */#define DNS_RRCLASS_HS            4     /* Hesiod [Dyer 87] */#define DNS_RRCLASS_FLUSH         0x800 /* Flush bit *//** Callback which is invoked when a hostname is found. * A function of this type must be implemented by the application using the DNS resolver. * @param name pointer to the name that was looked up. * @param ipaddr pointer to a struct ip_addr containing the IP address of the hostname, *        or NULL if the name could not be found (or on any other error). * @param callback_arg a user-specified callback argument passed to dns_gethostbyname*/typedef void (*dns_found_callback)(const char *name, struct ip_addr *ipaddr, void *callback_arg);void           dns_init(void);void           dns_tmr(void);void           dns_setserver(u8_t numdns, struct ip_addr *dnsserver);struct ip_addr dns_getserver(u8_t numdns);err_t          dns_gethostbyname(const char *hostname, struct ip_addr *addr,                                 dns_found_callback found, void *callback_arg);#endif /* LWIP_DNS */#endif /* __LWIP_DNS_H__ */