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 #ifdef __cplusplus 42 extern "C" { 43 #endif 44 45 /** DNS timer period */ 46 #define DNS_TMR_INTERVAL 1000 47 48 /** DNS field TYPE used for "Resource Records" */ 49 #define DNS_RRTYPE_A 1 /* a host address */ 50 #define DNS_RRTYPE_NS 2 /* an authoritative name server */ 51 #define DNS_RRTYPE_MD 3 /* a mail destination (Obsolete - use MX) */ 52 #define DNS_RRTYPE_MF 4 /* a mail forwarder (Obsolete - use MX) */ 53 #define DNS_RRTYPE_CNAME 5 /* the canonical name for an alias */ 54 #define DNS_RRTYPE_SOA 6 /* marks the start of a zone of authority */ 55 #define DNS_RRTYPE_MB 7 /* a mailbox domain name (EXPERIMENTAL) */ 56 #define DNS_RRTYPE_MG 8 /* a mail group member (EXPERIMENTAL) */ 57 #define DNS_RRTYPE_MR 9 /* a mail rename domain name (EXPERIMENTAL) */ 58 #define DNS_RRTYPE_NULL 10 /* a null RR (EXPERIMENTAL) */ 59 #define DNS_RRTYPE_WKS 11 /* a well known service description */ 60 #define DNS_RRTYPE_PTR 12 /* a domain name pointer */ 61 #define DNS_RRTYPE_HINFO 13 /* host information */ 62 #define DNS_RRTYPE_MINFO 14 /* mailbox or mail list information */ 63 #define DNS_RRTYPE_MX 15 /* mail exchange */ 64 #define DNS_RRTYPE_TXT 16 /* text strings */ 65 66 /** DNS field CLASS used for "Resource Records" */ 67 #define DNS_RRCLASS_IN 1 /* the Internet */ 68 #define DNS_RRCLASS_CS 2 /* the CSNET class (Obsolete - used only for examples in some obsolete RFCs) */ 69 #define DNS_RRCLASS_CH 3 /* the CHAOS class */ 70 #define DNS_RRCLASS_HS 4 /* Hesiod [Dyer 87] */ 71 #define DNS_RRCLASS_FLUSH 0x800 /* Flush bit */ 72 73 /* The size used for the next line is rather a hack, but it prevents including socket.h in all files 74 that include memp.h, and that would possibly break portability (since socket.h defines some types 75 and constants possibly already define by the OS). 76 Calculation rule: 77 sizeof(struct addrinfo) + sizeof(struct sockaddr_in) + DNS_MAX_NAME_LENGTH + 1 byte zero-termination */ 78 #define NETDB_ELEM_SIZE (32 + 16 + DNS_MAX_NAME_LENGTH + 1) 79 80 #if DNS_LOCAL_HOSTLIST 81 /** struct used for local host-list */ 82 struct local_hostlist_entry { 83 /** static hostname */ 84 const char *name; 85 /** static host address in network byteorder */ 86 ip_addr_t addr; 87 struct local_hostlist_entry *next; 88 }; 89 #if DNS_LOCAL_HOSTLIST_IS_DYNAMIC 90 #ifndef DNS_LOCAL_HOSTLIST_MAX_NAMELEN 91 #define DNS_LOCAL_HOSTLIST_MAX_NAMELEN DNS_MAX_NAME_LENGTH 92 #endif 93 #define LOCALHOSTLIST_ELEM_SIZE ((sizeof(struct local_hostlist_entry) + DNS_LOCAL_HOSTLIST_MAX_NAMELEN + 1)) 94 #endif /* DNS_LOCAL_HOSTLIST_IS_DYNAMIC */ 95 #endif /* DNS_LOCAL_HOSTLIST */ 96 97 /** Callback which is invoked when a hostname is found. 98 * A function of this type must be implemented by the application using the DNS resolver. 99 * @param name pointer to the name that was looked up. 100 * @param ipaddr pointer to an ip_addr_t containing the IP address of the hostname, 101 * or NULL if the name could not be found (or on any other error). 102 * @param callback_arg a user-specified callback argument passed to dns_gethostbyname 103 */ 104 typedef void (*dns_found_callback)(const char *name, ip_addr_t *ipaddr, void *callback_arg); 105 106 void dns_init(void); 107 void dns_tmr(void); 108 void dns_setserver(u8_t numdns, ip_addr_t *dnsserver); 109 ip_addr_t dns_getserver(u8_t numdns); 110 err_t dns_gethostbyname(const char *hostname, ip_addr_t *addr, 111 dns_found_callback found, void *callback_arg); 112 113 #if DNS_LOCAL_HOSTLIST && DNS_LOCAL_HOSTLIST_IS_DYNAMIC 114 int dns_local_removehost(const char *hostname, const ip_addr_t *addr); 115 err_t dns_local_addhost(const char *hostname, const ip_addr_t *addr); 116 #endif /* DNS_LOCAL_HOSTLIST && DNS_LOCAL_HOSTLIST_IS_DYNAMIC */ 117 118 #ifdef __cplusplus 119 } 120 #endif 121 122 #endif /* LWIP_DNS */ 123 124 #endif /* __LWIP_DNS_H__ */ 125