1/**
2 * lwip DNS resolver header file.
3
4 * Author: Jim Pettinato
5 *   April 2007
6
7 * ported from uIP resolv.c Copyright (c) 2002-2003, Adam Dunkels.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 * 1. Redistributions of source code must retain the above copyright
13 *    notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 *    notice, this list of conditions and the following disclaimer in the
16 *    documentation and/or other materials provided with the distribution.
17 * 3. The name of the author may not be used to endorse or promote
18 *    products derived from this software without specific prior
19 *    written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
22 * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
23 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
25 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
27 * GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
28 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
29 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
30 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
31 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
32 */
33
34#ifndef __LWIP_DNS_H__
35#define __LWIP_DNS_H__
36
37#include "lwip/opt.h"
38
39#if LWIP_DNS                    /* don't build if not configured for use in lwipopts.h */
40
41/** DNS timer period */
42#define DNS_TMR_INTERVAL          1000
43
44/** DNS field TYPE used for "Resource Records" */
45#define DNS_RRTYPE_A              1     /* a host address */
46#define DNS_RRTYPE_NS             2     /* an authoritative name server */
47#define DNS_RRTYPE_MD             3     /* a mail destination (Obsolete - use MX) */
48#define DNS_RRTYPE_MF             4     /* a mail forwarder (Obsolete - use MX) */
49#define DNS_RRTYPE_CNAME          5     /* the canonical name for an alias */
50#define DNS_RRTYPE_SOA            6     /* marks the start of a zone of authority */
51#define DNS_RRTYPE_MB             7     /* a mailbox domain name (EXPERIMENTAL) */
52#define DNS_RRTYPE_MG             8     /* a mail group member (EXPERIMENTAL) */
53#define DNS_RRTYPE_MR             9     /* a mail rename domain name (EXPERIMENTAL) */
54#define DNS_RRTYPE_NULL           10    /* a null RR (EXPERIMENTAL) */
55#define DNS_RRTYPE_WKS            11    /* a well known service description */
56#define DNS_RRTYPE_PTR            12    /* a domain name pointer */
57#define DNS_RRTYPE_HINFO          13    /* host information */
58#define DNS_RRTYPE_MINFO          14    /* mailbox or mail list information */
59#define DNS_RRTYPE_MX             15    /* mail exchange */
60#define DNS_RRTYPE_TXT            16    /* text strings */
61
62/** DNS field CLASS used for "Resource Records" */
63#define DNS_RRCLASS_IN            1     /* the Internet */
64#define DNS_RRCLASS_CS            2     /* the CSNET class (Obsolete - used only for examples in some obsolete RFCs) */
65#define DNS_RRCLASS_CH            3     /* the CHAOS class */
66#define DNS_RRCLASS_HS            4     /* Hesiod [Dyer 87] */
67#define DNS_RRCLASS_FLUSH         0x800 /* Flush bit */
68
69/** Callback which is invoked when a hostname is found.
70 * A function of this type must be implemented by the application using the DNS resolver.
71 * @param name pointer to the name that was looked up.
72 * @param ipaddr pointer to a struct ip_addr containing the IP address of the hostname,
73 *        or NULL if the name could not be found (or on any other error).
74 * @param callback_arg a user-specified callback argument passed to dns_gethostbyname
75*/
76typedef void (*dns_found_callback) (const char *name, struct ip_addr * ipaddr,
77                                    void *callback_arg);
78
79
80void dns_init(void);
81
82void dns_tmr(void);
83
84void dns_setserver(u8_t numdns, struct ip_addr *dnsserver);
85
86struct ip_addr dns_getserver(u8_t numdns);
87
88err_t dns_gethostbyname(const char *hostname, struct ip_addr *addr,
89                        dns_found_callback found, void *callback_arg);
90
91#if DNS_LOCAL_HOSTLIST && DNS_LOCAL_HOSTLIST_IS_DYNAMIC
92int dns_local_removehost(const char *hostname, const struct ip_addr *addr);
93err_t dns_local_addhost(const char *hostname, const struct ip_addr *addr);
94#endif                          /* DNS_LOCAL_HOSTLIST && DNS_LOCAL_HOSTLIST_IS_DYNAMIC */
95
96#endif                          /* LWIP_DNS */
97
98#endif                          /* __LWIP_DNS_H__ */
99