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Core/lwIP/core/dns.c@0:6dee052a3fa4, 2011-07-26 (annotated)

Committer:: nandgate
Date:: Tue Jul 26 05:30:53 2011 +0000
Revision:: 0:6dee052a3fa4

Who changed what in which revision?

User	Revision	Line number	New contents of line
nandgate	0:6dee052a3fa4	1	/**
nandgate	0:6dee052a3fa4	2	* @file
nandgate	0:6dee052a3fa4	3	* DNS - host name to IP address resolver.
nandgate	0:6dee052a3fa4	4	*
nandgate	0:6dee052a3fa4	5	*/
nandgate	0:6dee052a3fa4	6
nandgate	0:6dee052a3fa4	7	/**
nandgate	0:6dee052a3fa4	8
nandgate	0:6dee052a3fa4	9	* This file implements a DNS host name to IP address resolver.
nandgate	0:6dee052a3fa4	10
nandgate	0:6dee052a3fa4	11	* Port to lwIP from uIP
nandgate	0:6dee052a3fa4	12	* by Jim Pettinato April 2007
nandgate	0:6dee052a3fa4	13
nandgate	0:6dee052a3fa4	14	* uIP version Copyright (c) 2002-2003, Adam Dunkels.
nandgate	0:6dee052a3fa4	15	* All rights reserved.
nandgate	0:6dee052a3fa4	16	*
nandgate	0:6dee052a3fa4	17	* Redistribution and use in source and binary forms, with or without
nandgate	0:6dee052a3fa4	18	* modification, are permitted provided that the following conditions
nandgate	0:6dee052a3fa4	19	* are met:
nandgate	0:6dee052a3fa4	20	* 1. Redistributions of source code must retain the above copyright
nandgate	0:6dee052a3fa4	21	* notice, this list of conditions and the following disclaimer.
nandgate	0:6dee052a3fa4	22	* 2. Redistributions in binary form must reproduce the above copyright
nandgate	0:6dee052a3fa4	23	* notice, this list of conditions and the following disclaimer in the
nandgate	0:6dee052a3fa4	24	* documentation and/or other materials provided with the distribution.
nandgate	0:6dee052a3fa4	25	* 3. The name of the author may not be used to endorse or promote
nandgate	0:6dee052a3fa4	26	* products derived from this software without specific prior
nandgate	0:6dee052a3fa4	27	* written permission.
nandgate	0:6dee052a3fa4	28	*
nandgate	0:6dee052a3fa4	29	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
nandgate	0:6dee052a3fa4	30	* OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
nandgate	0:6dee052a3fa4	31	* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
nandgate	0:6dee052a3fa4	32	* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
nandgate	0:6dee052a3fa4	33	* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
nandgate	0:6dee052a3fa4	34	* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
nandgate	0:6dee052a3fa4	35	* GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
nandgate	0:6dee052a3fa4	36	* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
nandgate	0:6dee052a3fa4	37	* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
nandgate	0:6dee052a3fa4	38	* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
nandgate	0:6dee052a3fa4	39	* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
nandgate	0:6dee052a3fa4	40	*
nandgate	0:6dee052a3fa4	41	*
nandgate	0:6dee052a3fa4	42	* DNS.C
nandgate	0:6dee052a3fa4	43	*
nandgate	0:6dee052a3fa4	44	* The lwIP DNS resolver functions are used to lookup a host name and
nandgate	0:6dee052a3fa4	45	* map it to a numerical IP address. It maintains a list of resolved
nandgate	0:6dee052a3fa4	46	* hostnames that can be queried with the dns_lookup() function.
nandgate	0:6dee052a3fa4	47	* New hostnames can be resolved using the dns_query() function.
nandgate	0:6dee052a3fa4	48	*
nandgate	0:6dee052a3fa4	49	* The lwIP version of the resolver also adds a non-blocking version of
nandgate	0:6dee052a3fa4	50	* gethostbyname() that will work with a raw API application. This function
nandgate	0:6dee052a3fa4	51	* checks for an IP address string first and converts it if it is valid.
nandgate	0:6dee052a3fa4	52	* gethostbyname() then does a dns_lookup() to see if the name is
nandgate	0:6dee052a3fa4	53	* already in the table. If so, the IP is returned. If not, a query is
nandgate	0:6dee052a3fa4	54	* issued and the function returns with a ERR_INPROGRESS status. The app
nandgate	0:6dee052a3fa4	55	* using the dns client must then go into a waiting state.
nandgate	0:6dee052a3fa4	56	*
nandgate	0:6dee052a3fa4	57	* Once a hostname has been resolved (or found to be non-existent),
nandgate	0:6dee052a3fa4	58	* the resolver code calls a specified callback function (which
nandgate	0:6dee052a3fa4	59	* must be implemented by the module that uses the resolver).
nandgate	0:6dee052a3fa4	60	*/
nandgate	0:6dee052a3fa4	61
nandgate	0:6dee052a3fa4	62	/*-----------------------------------------------------------------------------
nandgate	0:6dee052a3fa4	63	* RFC 1035 - Domain names - implementation and specification
nandgate	0:6dee052a3fa4	64	* RFC 2181 - Clarifications to the DNS Specification
nandgate	0:6dee052a3fa4	65	----------------------------------------------------------------------------/
nandgate	0:6dee052a3fa4	66
nandgate	0:6dee052a3fa4	67	/** @todo: define good default values (rfc compliance) */
nandgate	0:6dee052a3fa4	68	/** @todo: improve answer parsing, more checkings... */
nandgate	0:6dee052a3fa4	69	/** @todo: check RFC1035 - 7.3. Processing responses */
nandgate	0:6dee052a3fa4	70
nandgate	0:6dee052a3fa4	71	/*-----------------------------------------------------------------------------
nandgate	0:6dee052a3fa4	72	* Includes
nandgate	0:6dee052a3fa4	73	----------------------------------------------------------------------------/
nandgate	0:6dee052a3fa4	74
nandgate	0:6dee052a3fa4	75	#include "lwip/opt.h"
nandgate	0:6dee052a3fa4	76
nandgate	0:6dee052a3fa4	77	#if LWIP_DNS /* don't build if not configured for use in lwipopts.h */
nandgate	0:6dee052a3fa4	78
nandgate	0:6dee052a3fa4	79	#include "lwip/udp.h"
nandgate	0:6dee052a3fa4	80	#include "lwip/mem.h"
nandgate	0:6dee052a3fa4	81	#include "lwip/dns.h"
nandgate	0:6dee052a3fa4	82
nandgate	0:6dee052a3fa4	83	#include <string.h>
nandgate	0:6dee052a3fa4	84
nandgate	0:6dee052a3fa4	85	/** DNS server IP address */
nandgate	0:6dee052a3fa4	86	#ifndef DNS_SERVER_ADDRESS
nandgate	0:6dee052a3fa4	87	#define DNS_SERVER_ADDRESS inet_addr("208.67.222.222") /* resolver1.opendns.com */
nandgate	0:6dee052a3fa4	88	#endif
nandgate	0:6dee052a3fa4	89
nandgate	0:6dee052a3fa4	90	/** DNS server port address */
nandgate	0:6dee052a3fa4	91	#ifndef DNS_SERVER_PORT
nandgate	0:6dee052a3fa4	92	#define DNS_SERVER_PORT 53
nandgate	0:6dee052a3fa4	93	#endif
nandgate	0:6dee052a3fa4	94
nandgate	0:6dee052a3fa4	95	/** DNS maximum number of retries when asking for a name, before "timeout". */
nandgate	0:6dee052a3fa4	96	#ifndef DNS_MAX_RETRIES
nandgate	0:6dee052a3fa4	97	#define DNS_MAX_RETRIES 4
nandgate	0:6dee052a3fa4	98	#endif
nandgate	0:6dee052a3fa4	99
nandgate	0:6dee052a3fa4	100	/** DNS resource record max. TTL (one week as default) */
nandgate	0:6dee052a3fa4	101	#ifndef DNS_MAX_TTL
nandgate	0:6dee052a3fa4	102	#define DNS_MAX_TTL 604800
nandgate	0:6dee052a3fa4	103	#endif
nandgate	0:6dee052a3fa4	104
nandgate	0:6dee052a3fa4	105	/* DNS protocol flags */
nandgate	0:6dee052a3fa4	106	#define DNS_FLAG1_RESPONSE 0x80
nandgate	0:6dee052a3fa4	107	#define DNS_FLAG1_OPCODE_STATUS 0x10
nandgate	0:6dee052a3fa4	108	#define DNS_FLAG1_OPCODE_INVERSE 0x08
nandgate	0:6dee052a3fa4	109	#define DNS_FLAG1_OPCODE_STANDARD 0x00
nandgate	0:6dee052a3fa4	110	#define DNS_FLAG1_AUTHORATIVE 0x04
nandgate	0:6dee052a3fa4	111	#define DNS_FLAG1_TRUNC 0x02
nandgate	0:6dee052a3fa4	112	#define DNS_FLAG1_RD 0x01
nandgate	0:6dee052a3fa4	113	#define DNS_FLAG2_RA 0x80
nandgate	0:6dee052a3fa4	114	#define DNS_FLAG2_ERR_MASK 0x0f
nandgate	0:6dee052a3fa4	115	#define DNS_FLAG2_ERR_NONE 0x00
nandgate	0:6dee052a3fa4	116	#define DNS_FLAG2_ERR_NAME 0x03
nandgate	0:6dee052a3fa4	117
nandgate	0:6dee052a3fa4	118	/* DNS protocol states */
nandgate	0:6dee052a3fa4	119	#define DNS_STATE_UNUSED 0
nandgate	0:6dee052a3fa4	120	#define DNS_STATE_NEW 1
nandgate	0:6dee052a3fa4	121	#define DNS_STATE_ASKING 2
nandgate	0:6dee052a3fa4	122	#define DNS_STATE_DONE 3
nandgate	0:6dee052a3fa4	123
nandgate	0:6dee052a3fa4	124
nandgate	0:6dee052a3fa4	125	// XXX: For C++ compatibility
nandgate	0:6dee052a3fa4	126	#define class mclass
nandgate	0:6dee052a3fa4	127
nandgate	0:6dee052a3fa4	128	#ifdef PACK_STRUCT_USE_INCLUDES
nandgate	0:6dee052a3fa4	129	# include "arch/bpstruct.h"
nandgate	0:6dee052a3fa4	130	#endif
nandgate	0:6dee052a3fa4	131	PACK_STRUCT_BEGIN
nandgate	0:6dee052a3fa4	132	/** DNS message header */
nandgate	0:6dee052a3fa4	133	struct dns_hdr {
nandgate	0:6dee052a3fa4	134	PACK_STRUCT_FIELD(u16_t id);
nandgate	0:6dee052a3fa4	135	PACK_STRUCT_FIELD(u8_t flags1);
nandgate	0:6dee052a3fa4	136	PACK_STRUCT_FIELD(u8_t flags2);
nandgate	0:6dee052a3fa4	137	PACK_STRUCT_FIELD(u16_t numquestions);
nandgate	0:6dee052a3fa4	138	PACK_STRUCT_FIELD(u16_t numanswers);
nandgate	0:6dee052a3fa4	139	PACK_STRUCT_FIELD(u16_t numauthrr);
nandgate	0:6dee052a3fa4	140	PACK_STRUCT_FIELD(u16_t numextrarr);
nandgate	0:6dee052a3fa4	141	} PACK_STRUCT_STRUCT;
nandgate	0:6dee052a3fa4	142	PACK_STRUCT_END
nandgate	0:6dee052a3fa4	143	#ifdef PACK_STRUCT_USE_INCLUDES
nandgate	0:6dee052a3fa4	144	# include "arch/epstruct.h"
nandgate	0:6dee052a3fa4	145	#endif
nandgate	0:6dee052a3fa4	146	#define SIZEOF_DNS_HDR 12
nandgate	0:6dee052a3fa4	147
nandgate	0:6dee052a3fa4	148	#ifdef PACK_STRUCT_USE_INCLUDES
nandgate	0:6dee052a3fa4	149	# include "arch/bpstruct.h"
nandgate	0:6dee052a3fa4	150	#endif
nandgate	0:6dee052a3fa4	151	PACK_STRUCT_BEGIN
nandgate	0:6dee052a3fa4	152	/** DNS query message structure */
nandgate	0:6dee052a3fa4	153	struct dns_query {
nandgate	0:6dee052a3fa4	154	/* DNS query record starts with either a domain name or a pointer
nandgate	0:6dee052a3fa4	155	to a name already present somewhere in the packet. */
nandgate	0:6dee052a3fa4	156	PACK_STRUCT_FIELD(u16_t type);
nandgate	0:6dee052a3fa4	157	PACK_STRUCT_FIELD(u16_t class);
nandgate	0:6dee052a3fa4	158	} PACK_STRUCT_STRUCT;
nandgate	0:6dee052a3fa4	159	PACK_STRUCT_END
nandgate	0:6dee052a3fa4	160	#ifdef PACK_STRUCT_USE_INCLUDES
nandgate	0:6dee052a3fa4	161	# include "arch/epstruct.h"
nandgate	0:6dee052a3fa4	162	#endif
nandgate	0:6dee052a3fa4	163	#define SIZEOF_DNS_QUERY 4
nandgate	0:6dee052a3fa4	164
nandgate	0:6dee052a3fa4	165	#ifdef PACK_STRUCT_USE_INCLUDES
nandgate	0:6dee052a3fa4	166	# include "arch/bpstruct.h"
nandgate	0:6dee052a3fa4	167	#endif
nandgate	0:6dee052a3fa4	168	PACK_STRUCT_BEGIN
nandgate	0:6dee052a3fa4	169	/** DNS answer message structure */
nandgate	0:6dee052a3fa4	170	struct dns_answer {
nandgate	0:6dee052a3fa4	171	/* DNS answer record starts with either a domain name or a pointer
nandgate	0:6dee052a3fa4	172	to a name already present somewhere in the packet. */
nandgate	0:6dee052a3fa4	173	PACK_STRUCT_FIELD(u16_t type);
nandgate	0:6dee052a3fa4	174	PACK_STRUCT_FIELD(u16_t class);
nandgate	0:6dee052a3fa4	175	PACK_STRUCT_FIELD(u32_t ttl);
nandgate	0:6dee052a3fa4	176	PACK_STRUCT_FIELD(u16_t len);
nandgate	0:6dee052a3fa4	177	} PACK_STRUCT_STRUCT;
nandgate	0:6dee052a3fa4	178	PACK_STRUCT_END
nandgate	0:6dee052a3fa4	179	#ifdef PACK_STRUCT_USE_INCLUDES
nandgate	0:6dee052a3fa4	180	# include "arch/epstruct.h"
nandgate	0:6dee052a3fa4	181	#endif
nandgate	0:6dee052a3fa4	182	#define SIZEOF_DNS_ANSWER 10
nandgate	0:6dee052a3fa4	183
nandgate	0:6dee052a3fa4	184	/** DNS table entry */
nandgate	0:6dee052a3fa4	185	struct dns_table_entry {
nandgate	0:6dee052a3fa4	186	u8_t state;
nandgate	0:6dee052a3fa4	187	u8_t numdns;
nandgate	0:6dee052a3fa4	188	u8_t tmr;
nandgate	0:6dee052a3fa4	189	u8_t retries;
nandgate	0:6dee052a3fa4	190	u8_t seqno;
nandgate	0:6dee052a3fa4	191	u8_t err;
nandgate	0:6dee052a3fa4	192	u32_t ttl;
nandgate	0:6dee052a3fa4	193	char name[DNS_MAX_NAME_LENGTH];
nandgate	0:6dee052a3fa4	194	struct ip_addr ipaddr;
nandgate	0:6dee052a3fa4	195	/* pointer to callback on DNS query done */
nandgate	0:6dee052a3fa4	196	dns_found_callback found;
nandgate	0:6dee052a3fa4	197	void *arg;
nandgate	0:6dee052a3fa4	198	};
nandgate	0:6dee052a3fa4	199
nandgate	0:6dee052a3fa4	200	#if DNS_LOCAL_HOSTLIST
nandgate	0:6dee052a3fa4	201	/** struct used for local host-list */
nandgate	0:6dee052a3fa4	202	struct local_hostlist_entry {
nandgate	0:6dee052a3fa4	203	/** static hostname */
nandgate	0:6dee052a3fa4	204	const char *name;
nandgate	0:6dee052a3fa4	205	/** static host address in network byteorder */
nandgate	0:6dee052a3fa4	206	u32_t addr;
nandgate	0:6dee052a3fa4	207	struct local_hostlist_entry *next;
nandgate	0:6dee052a3fa4	208	};
nandgate	0:6dee052a3fa4	209
nandgate	0:6dee052a3fa4	210	#if DNS_LOCAL_HOSTLIST_IS_DYNAMIC
nandgate	0:6dee052a3fa4	211	/** Local host-list. For hostnames in this list, no
nandgate	0:6dee052a3fa4	212	* external name resolution is performed */
nandgate	0:6dee052a3fa4	213	static struct local_hostlist_entry *local_hostlist_dynamic;
nandgate	0:6dee052a3fa4	214	#else /* DNS_LOCAL_HOSTLIST_IS_DYNAMIC */
nandgate	0:6dee052a3fa4	215
nandgate	0:6dee052a3fa4	216	/** Defining this allows the local_hostlist_static to be placed in a different
nandgate	0:6dee052a3fa4	217	* linker section (e.g. FLASH) */
nandgate	0:6dee052a3fa4	218	#ifndef DNS_LOCAL_HOSTLIST_STORAGE_PRE
nandgate	0:6dee052a3fa4	219	#define DNS_LOCAL_HOSTLIST_STORAGE_PRE static
nandgate	0:6dee052a3fa4	220	#endif /* DNS_LOCAL_HOSTLIST_STORAGE_PRE */
nandgate	0:6dee052a3fa4	221	/** Defining this allows the local_hostlist_static to be placed in a different
nandgate	0:6dee052a3fa4	222	* linker section (e.g. FLASH) */
nandgate	0:6dee052a3fa4	223	#ifndef DNS_LOCAL_HOSTLIST_STORAGE_POST
nandgate	0:6dee052a3fa4	224	#define DNS_LOCAL_HOSTLIST_STORAGE_POST
nandgate	0:6dee052a3fa4	225	#endif /* DNS_LOCAL_HOSTLIST_STORAGE_POST */
nandgate	0:6dee052a3fa4	226	DNS_LOCAL_HOSTLIST_STORAGE_PRE struct local_hostlist_entry local_hostlist_static[]
nandgate	0:6dee052a3fa4	227	DNS_LOCAL_HOSTLIST_STORAGE_POST = DNS_LOCAL_HOSTLIST_INIT;
nandgate	0:6dee052a3fa4	228
nandgate	0:6dee052a3fa4	229	#endif /* DNS_LOCAL_HOSTLIST_IS_DYNAMIC */
nandgate	0:6dee052a3fa4	230
nandgate	0:6dee052a3fa4	231	static void dns_init_local();
nandgate	0:6dee052a3fa4	232	#endif /* DNS_LOCAL_HOSTLIST */
nandgate	0:6dee052a3fa4	233
nandgate	0:6dee052a3fa4	234
nandgate	0:6dee052a3fa4	235	/* forward declarations */
nandgate	0:6dee052a3fa4	236	static void dns_recv(void s, struct udp_pcb pcb, struct pbuf p, struct ip_addr addr, u16_t port);
nandgate	0:6dee052a3fa4	237	static void dns_check_entries(void);
nandgate	0:6dee052a3fa4	238
nandgate	0:6dee052a3fa4	239	/*-----------------------------------------------------------------------------
nandgate	0:6dee052a3fa4	240	* Globales
nandgate	0:6dee052a3fa4	241	----------------------------------------------------------------------------/
nandgate	0:6dee052a3fa4	242
nandgate	0:6dee052a3fa4	243	/* DNS variables */
nandgate	0:6dee052a3fa4	244	static struct udp_pcb *dns_pcb;
nandgate	0:6dee052a3fa4	245	static u8_t dns_seqno;
nandgate	0:6dee052a3fa4	246	static struct dns_table_entry dns_table[DNS_TABLE_SIZE] MEM_POSITION;
nandgate	0:6dee052a3fa4	247	static struct ip_addr dns_servers[DNS_MAX_SERVERS] MEM_POSITION;
nandgate	0:6dee052a3fa4	248
nandgate	0:6dee052a3fa4	249	#if (DNS_USES_STATIC_BUF == 1)
nandgate	0:6dee052a3fa4	250	static u8_t dns_payload[DNS_MSG_SIZE] MEM_POSITION;
nandgate	0:6dee052a3fa4	251	#endif /* (DNS_USES_STATIC_BUF == 1) */
nandgate	0:6dee052a3fa4	252
nandgate	0:6dee052a3fa4	253	/**
nandgate	0:6dee052a3fa4	254	* Initialize the resolver: set up the UDP pcb and configure the default server
nandgate	0:6dee052a3fa4	255	* (DNS_SERVER_ADDRESS).
nandgate	0:6dee052a3fa4	256	*/
nandgate	0:6dee052a3fa4	257	void
nandgate	0:6dee052a3fa4	258	dns_init()
nandgate	0:6dee052a3fa4	259	{
nandgate	0:6dee052a3fa4	260	struct ip_addr dnsserver;
nandgate	0:6dee052a3fa4	261
nandgate	0:6dee052a3fa4	262	/* initialize default DNS server address */
nandgate	0:6dee052a3fa4	263	dnsserver.addr = DNS_SERVER_ADDRESS;
nandgate	0:6dee052a3fa4	264
nandgate	0:6dee052a3fa4	265	LWIP_DEBUGF(DNS_DEBUG, ("dns_init: initializing\n"));
nandgate	0:6dee052a3fa4	266
nandgate	0:6dee052a3fa4	267	/* if dns client not yet initialized... */
nandgate	0:6dee052a3fa4	268	if (dns_pcb == NULL) {
nandgate	0:6dee052a3fa4	269	dns_pcb = udp_new();
nandgate	0:6dee052a3fa4	270
nandgate	0:6dee052a3fa4	271	if (dns_pcb != NULL) {
nandgate	0:6dee052a3fa4	272	/* initialize DNS table not needed (initialized to zero since it is a
nandgate	0:6dee052a3fa4	273	* global variable) */
nandgate	0:6dee052a3fa4	274	LWIP_ASSERT("For implicit initialization to work, DNS_STATE_UNUSED needs to be 0",
nandgate	0:6dee052a3fa4	275	DNS_STATE_UNUSED == 0);
nandgate	0:6dee052a3fa4	276
nandgate	0:6dee052a3fa4	277	/* initialize DNS client */
nandgate	0:6dee052a3fa4	278	udp_bind(dns_pcb, IP_ADDR_ANY, 0);
nandgate	0:6dee052a3fa4	279	udp_recv(dns_pcb, dns_recv, NULL);
nandgate	0:6dee052a3fa4	280
nandgate	0:6dee052a3fa4	281	/* initialize default DNS primary server */
nandgate	0:6dee052a3fa4	282	dns_setserver(0, &dnsserver);
nandgate	0:6dee052a3fa4	283	}
nandgate	0:6dee052a3fa4	284	}
nandgate	0:6dee052a3fa4	285	#if DNS_LOCAL_HOSTLIST
nandgate	0:6dee052a3fa4	286	dns_init_local();
nandgate	0:6dee052a3fa4	287	#endif
nandgate	0:6dee052a3fa4	288	}
nandgate	0:6dee052a3fa4	289
nandgate	0:6dee052a3fa4	290	/**
nandgate	0:6dee052a3fa4	291	* Initialize one of the DNS servers.
nandgate	0:6dee052a3fa4	292	*
nandgate	0:6dee052a3fa4	293	* @param numdns the index of the DNS server to set must be < DNS_MAX_SERVERS
nandgate	0:6dee052a3fa4	294	* @param dnsserver IP address of the DNS server to set
nandgate	0:6dee052a3fa4	295	*/
nandgate	0:6dee052a3fa4	296	void
nandgate	0:6dee052a3fa4	297	dns_setserver(u8_t numdns, struct ip_addr *dnsserver)
nandgate	0:6dee052a3fa4	298	{
nandgate	0:6dee052a3fa4	299	if ((numdns < DNS_MAX_SERVERS) && (dns_pcb != NULL) &&
nandgate	0:6dee052a3fa4	300	(dnsserver != NULL) && (dnsserver->addr !=0 )) {
nandgate	0:6dee052a3fa4	301	dns_servers[numdns] = (*dnsserver);
nandgate	0:6dee052a3fa4	302	}
nandgate	0:6dee052a3fa4	303	}
nandgate	0:6dee052a3fa4	304
nandgate	0:6dee052a3fa4	305	/**
nandgate	0:6dee052a3fa4	306	* Obtain one of the currently configured DNS server.
nandgate	0:6dee052a3fa4	307	*
nandgate	0:6dee052a3fa4	308	* @param numdns the index of the DNS server
nandgate	0:6dee052a3fa4	309	* @return IP address of the indexed DNS server or "ip_addr_any" if the DNS
nandgate	0:6dee052a3fa4	310	* server has not been configured.
nandgate	0:6dee052a3fa4	311	*/
nandgate	0:6dee052a3fa4	312	struct ip_addr
nandgate	0:6dee052a3fa4	313	dns_getserver(u8_t numdns)
nandgate	0:6dee052a3fa4	314	{
nandgate	0:6dee052a3fa4	315	if (numdns < DNS_MAX_SERVERS) {
nandgate	0:6dee052a3fa4	316	return dns_servers[numdns];
nandgate	0:6dee052a3fa4	317	} else {
nandgate	0:6dee052a3fa4	318	return *IP_ADDR_ANY;
nandgate	0:6dee052a3fa4	319	}
nandgate	0:6dee052a3fa4	320	}
nandgate	0:6dee052a3fa4	321
nandgate	0:6dee052a3fa4	322	/**
nandgate	0:6dee052a3fa4	323	* The DNS resolver client timer - handle retries and timeouts and should
nandgate	0:6dee052a3fa4	324	* be called every DNS_TMR_INTERVAL milliseconds (every second by default).
nandgate	0:6dee052a3fa4	325	*/
nandgate	0:6dee052a3fa4	326	void
nandgate	0:6dee052a3fa4	327	dns_tmr(void)
nandgate	0:6dee052a3fa4	328	{
nandgate	0:6dee052a3fa4	329	if (dns_pcb != NULL) {
nandgate	0:6dee052a3fa4	330	LWIP_DEBUGF(DNS_DEBUG, ("dns_tmr: dns_check_entries\n"));
nandgate	0:6dee052a3fa4	331	dns_check_entries();
nandgate	0:6dee052a3fa4	332	}
nandgate	0:6dee052a3fa4	333	}
nandgate	0:6dee052a3fa4	334
nandgate	0:6dee052a3fa4	335	#if DNS_LOCAL_HOSTLIST
nandgate	0:6dee052a3fa4	336	static void
nandgate	0:6dee052a3fa4	337	dns_init_local()
nandgate	0:6dee052a3fa4	338	{
nandgate	0:6dee052a3fa4	339	#if DNS_LOCAL_HOSTLIST_IS_DYNAMIC && defined(DNS_LOCAL_HOSTLIST_INIT)
nandgate	0:6dee052a3fa4	340	int i;
nandgate	0:6dee052a3fa4	341	struct local_hostlist_entry *entry;
nandgate	0:6dee052a3fa4	342	/* Dynamic: copy entries from DNS_LOCAL_HOSTLIST_INIT to list */
nandgate	0:6dee052a3fa4	343	struct local_hostlist_entry local_hostlist_init[] = DNS_LOCAL_HOSTLIST_INIT;
nandgate	0:6dee052a3fa4	344	for (i = 0; i < sizeof(local_hostlist_init) / sizeof(struct local_hostlist_entry); i++) {
nandgate	0:6dee052a3fa4	345	entry = mem_malloc(sizeof(struct local_hostlist_entry));
nandgate	0:6dee052a3fa4	346	LWIP_ASSERT("mem-error in dns_init_local", entry != NULL);
nandgate	0:6dee052a3fa4	347	if (entry != NULL) {
nandgate	0:6dee052a3fa4	348	struct local_hostlist_entry *init_entry = &local_hostlist_init[i];
nandgate	0:6dee052a3fa4	349	entry->name = init_entry->name;
nandgate	0:6dee052a3fa4	350	entry->addr = init_entry->addr;
nandgate	0:6dee052a3fa4	351	entry->next = local_hostlist_dynamic;
nandgate	0:6dee052a3fa4	352	local_hostlist_dynamic = entry;
nandgate	0:6dee052a3fa4	353	}
nandgate	0:6dee052a3fa4	354	}
nandgate	0:6dee052a3fa4	355	#endif /* DNS_LOCAL_HOSTLIST_IS_DYNAMIC && defined(DNS_LOCAL_HOSTLIST_INIT) */
nandgate	0:6dee052a3fa4	356	}
nandgate	0:6dee052a3fa4	357
nandgate	0:6dee052a3fa4	358	/**
nandgate	0:6dee052a3fa4	359	* Scans the local host-list for a hostname.
nandgate	0:6dee052a3fa4	360	*
nandgate	0:6dee052a3fa4	361	* @param hostname Hostname to look for in the local host-list
nandgate	0:6dee052a3fa4	362	* @return The first IP address for the hostname in the local host-list or
nandgate	0:6dee052a3fa4	363	* INADDR_NONE if not found.
nandgate	0:6dee052a3fa4	364	*/
nandgate	0:6dee052a3fa4	365	static u32_t
nandgate	0:6dee052a3fa4	366	dns_lookup_local(const char *hostname)
nandgate	0:6dee052a3fa4	367	{
nandgate	0:6dee052a3fa4	368	#if DNS_LOCAL_HOSTLIST_IS_DYNAMIC
nandgate	0:6dee052a3fa4	369	struct local_hostlist_entry *entry = local_hostlist_dynamic;
nandgate	0:6dee052a3fa4	370	while(entry != NULL) {
nandgate	0:6dee052a3fa4	371	if(strcmp(entry->name, hostname) == 0) {
nandgate	0:6dee052a3fa4	372	return entry->addr;
nandgate	0:6dee052a3fa4	373	}
nandgate	0:6dee052a3fa4	374	entry = entry->next;
nandgate	0:6dee052a3fa4	375	}
nandgate	0:6dee052a3fa4	376	#else /* DNS_LOCAL_HOSTLIST_IS_DYNAMIC */
nandgate	0:6dee052a3fa4	377	int i;
nandgate	0:6dee052a3fa4	378	for (i = 0; i < sizeof(local_hostlist_static) / sizeof(struct local_hostlist_entry); i++) {
nandgate	0:6dee052a3fa4	379	if(strcmp(local_hostlist_static[i].name, hostname) == 0) {
nandgate	0:6dee052a3fa4	380	return local_hostlist_static[i].addr;
nandgate	0:6dee052a3fa4	381	}
nandgate	0:6dee052a3fa4	382	}
nandgate	0:6dee052a3fa4	383	#endif /* DNS_LOCAL_HOSTLIST_IS_DYNAMIC */
nandgate	0:6dee052a3fa4	384	return INADDR_NONE;
nandgate	0:6dee052a3fa4	385	}
nandgate	0:6dee052a3fa4	386
nandgate	0:6dee052a3fa4	387	#if DNS_LOCAL_HOSTLIST_IS_DYNAMIC
nandgate	0:6dee052a3fa4	388	/** Remove all entries from the local host-list for a specific hostname
nandgate	0:6dee052a3fa4	389	* and/or IP addess
nandgate	0:6dee052a3fa4	390	*
nandgate	0:6dee052a3fa4	391	* @param hostname hostname for which entries shall be removed from the local
nandgate	0:6dee052a3fa4	392	* host-list
nandgate	0:6dee052a3fa4	393	* @param addr address for which entries shall be removed from the local host-list
nandgate	0:6dee052a3fa4	394	* @return the number of removed entries
nandgate	0:6dee052a3fa4	395	*/
nandgate	0:6dee052a3fa4	396	int
nandgate	0:6dee052a3fa4	397	dns_local_removehost(const char hostname, const struct ip_addr addr)
nandgate	0:6dee052a3fa4	398	{
nandgate	0:6dee052a3fa4	399	int removed = 0;
nandgate	0:6dee052a3fa4	400	struct local_hostlist_entry *entry = local_hostlist_dynamic;
nandgate	0:6dee052a3fa4	401	struct local_hostlist_entry *last_entry = NULL;
nandgate	0:6dee052a3fa4	402	while (entry != NULL) {
nandgate	0:6dee052a3fa4	403	if (((hostname == NULL) \|\| !strcmp(entry->name, hostname)) &&
nandgate	0:6dee052a3fa4	404	((addr == NULL) \|\| (entry->addr == addr->addr))) {
nandgate	0:6dee052a3fa4	405	struct local_hostlist_entry *free_entry;
nandgate	0:6dee052a3fa4	406	if (last_entry != NULL) {
nandgate	0:6dee052a3fa4	407	last_entry->next = entry->next;
nandgate	0:6dee052a3fa4	408	} else {
nandgate	0:6dee052a3fa4	409	local_hostlist_dynamic = entry->next;
nandgate	0:6dee052a3fa4	410	}
nandgate	0:6dee052a3fa4	411	free_entry = entry;
nandgate	0:6dee052a3fa4	412	entry = entry->next;
nandgate	0:6dee052a3fa4	413	mem_free(free_entry);
nandgate	0:6dee052a3fa4	414	removed++;
nandgate	0:6dee052a3fa4	415	} else {
nandgate	0:6dee052a3fa4	416	last_entry = entry;
nandgate	0:6dee052a3fa4	417	entry = entry->next;
nandgate	0:6dee052a3fa4	418	}
nandgate	0:6dee052a3fa4	419	}
nandgate	0:6dee052a3fa4	420	return removed;
nandgate	0:6dee052a3fa4	421	}
nandgate	0:6dee052a3fa4	422
nandgate	0:6dee052a3fa4	423	/**
nandgate	0:6dee052a3fa4	424	* Add a hostname/IP address pair to the local host-list.
nandgate	0:6dee052a3fa4	425	* Duplicates are not checked.
nandgate	0:6dee052a3fa4	426	*
nandgate	0:6dee052a3fa4	427	* @param hostname hostname of the new entry
nandgate	0:6dee052a3fa4	428	* @param addr IP address of the new entry
nandgate	0:6dee052a3fa4	429	* @return ERR_OK if succeeded or ERR_MEM on memory error
nandgate	0:6dee052a3fa4	430	*/
nandgate	0:6dee052a3fa4	431	err_t
nandgate	0:6dee052a3fa4	432	dns_local_addhost(const char hostname, const struct ip_addr addr)
nandgate	0:6dee052a3fa4	433	{
nandgate	0:6dee052a3fa4	434	struct local_hostlist_entry *entry;
nandgate	0:6dee052a3fa4	435	entry = mem_malloc(sizeof(struct local_hostlist_entry));
nandgate	0:6dee052a3fa4	436	if (entry == NULL) {
nandgate	0:6dee052a3fa4	437	return ERR_MEM;
nandgate	0:6dee052a3fa4	438	}
nandgate	0:6dee052a3fa4	439	entry->name = hostname;
nandgate	0:6dee052a3fa4	440	entry->addr = addr->addr;
nandgate	0:6dee052a3fa4	441	entry->next = local_hostlist_dynamic;
nandgate	0:6dee052a3fa4	442	local_hostlist_dynamic = entry;
nandgate	0:6dee052a3fa4	443	return ERR_OK;
nandgate	0:6dee052a3fa4	444	}
nandgate	0:6dee052a3fa4	445	#endif /* DNS_LOCAL_HOSTLIST_IS_DYNAMIC*/
nandgate	0:6dee052a3fa4	446	#endif /* DNS_LOCAL_HOSTLIST */
nandgate	0:6dee052a3fa4	447
nandgate	0:6dee052a3fa4	448	/**
nandgate	0:6dee052a3fa4	449	* Look up a hostname in the array of known hostnames.
nandgate	0:6dee052a3fa4	450	*
nandgate	0:6dee052a3fa4	451	* @note This function only looks in the internal array of known
nandgate	0:6dee052a3fa4	452	* hostnames, it does not send out a query for the hostname if none
nandgate	0:6dee052a3fa4	453	* was found. The function dns_enqueue() can be used to send a query
nandgate	0:6dee052a3fa4	454	* for a hostname.
nandgate	0:6dee052a3fa4	455	*
nandgate	0:6dee052a3fa4	456	* @param name the hostname to look up
nandgate	0:6dee052a3fa4	457	* @return the hostname's IP address, as u32_t (instead of struct ip_addr to
nandgate	0:6dee052a3fa4	458	* better check for failure: != INADDR_NONE) or INADDR_NONE if the hostname
nandgate	0:6dee052a3fa4	459	* was not found in the cached dns_table.
nandgate	0:6dee052a3fa4	460	*/
nandgate	0:6dee052a3fa4	461	static u32_t
nandgate	0:6dee052a3fa4	462	dns_lookup(const char *name)
nandgate	0:6dee052a3fa4	463	{
nandgate	0:6dee052a3fa4	464	u8_t i;
nandgate	0:6dee052a3fa4	465	#if DNS_LOCAL_HOSTLIST \|\| defined(DNS_LOOKUP_LOCAL_EXTERN)
nandgate	0:6dee052a3fa4	466	u32_t addr;
nandgate	0:6dee052a3fa4	467	#endif /* DNS_LOCAL_HOSTLIST \|\| defined(DNS_LOOKUP_LOCAL_EXTERN) */
nandgate	0:6dee052a3fa4	468	#if DNS_LOCAL_HOSTLIST
nandgate	0:6dee052a3fa4	469	if ((addr = dns_lookup_local(name)) != INADDR_NONE) {
nandgate	0:6dee052a3fa4	470	return addr;
nandgate	0:6dee052a3fa4	471	}
nandgate	0:6dee052a3fa4	472	#endif /* DNS_LOCAL_HOSTLIST */
nandgate	0:6dee052a3fa4	473	#ifdef DNS_LOOKUP_LOCAL_EXTERN
nandgate	0:6dee052a3fa4	474	if((addr = DNS_LOOKUP_LOCAL_EXTERN(name)) != INADDR_NONE) {
nandgate	0:6dee052a3fa4	475	return addr;
nandgate	0:6dee052a3fa4	476	}
nandgate	0:6dee052a3fa4	477	#endif /* DNS_LOOKUP_LOCAL_EXTERN */
nandgate	0:6dee052a3fa4	478
nandgate	0:6dee052a3fa4	479	/* Walk through name list, return entry if found. If not, return NULL. */
nandgate	0:6dee052a3fa4	480	for (i = 0; i < DNS_TABLE_SIZE; ++i) {
nandgate	0:6dee052a3fa4	481	if ((dns_table[i].state == DNS_STATE_DONE) &&
nandgate	0:6dee052a3fa4	482	(strcmp(name, dns_table[i].name) == 0)) {
nandgate	0:6dee052a3fa4	483	LWIP_DEBUGF(DNS_DEBUG, ("dns_lookup: \"%s\": found = ", name));
nandgate	0:6dee052a3fa4	484	ip_addr_debug_print(DNS_DEBUG, &(dns_table[i].ipaddr));
nandgate	0:6dee052a3fa4	485	LWIP_DEBUGF(DNS_DEBUG, ("\n"));
nandgate	0:6dee052a3fa4	486	return dns_table[i].ipaddr.addr;
nandgate	0:6dee052a3fa4	487	}
nandgate	0:6dee052a3fa4	488	}
nandgate	0:6dee052a3fa4	489
nandgate	0:6dee052a3fa4	490	return INADDR_NONE;
nandgate	0:6dee052a3fa4	491	}
nandgate	0:6dee052a3fa4	492
nandgate	0:6dee052a3fa4	493	#if DNS_DOES_NAME_CHECK
nandgate	0:6dee052a3fa4	494	/**
nandgate	0:6dee052a3fa4	495	* Compare the "dotted" name "query" with the encoded name "response"
nandgate	0:6dee052a3fa4	496	* to make sure an answer from the DNS server matches the current dns_table
nandgate	0:6dee052a3fa4	497	* entry (otherwise, answers might arrive late for hostname not on the list
nandgate	0:6dee052a3fa4	498	* any more).
nandgate	0:6dee052a3fa4	499	*
nandgate	0:6dee052a3fa4	500	* @param query hostname (not encoded) from the dns_table
nandgate	0:6dee052a3fa4	501	* @param response encoded hostname in the DNS response
nandgate	0:6dee052a3fa4	502	* @return 0: names equal; 1: names differ
nandgate	0:6dee052a3fa4	503	*/
nandgate	0:6dee052a3fa4	504	static u8_t
nandgate	0:6dee052a3fa4	505	dns_compare_name(unsigned char query, unsigned char response)
nandgate	0:6dee052a3fa4	506	{
nandgate	0:6dee052a3fa4	507	unsigned char n;
nandgate	0:6dee052a3fa4	508
nandgate	0:6dee052a3fa4	509	do {
nandgate	0:6dee052a3fa4	510	n = *response++;
nandgate	0:6dee052a3fa4	511	/** @see RFC 1035 - 4.1.4. Message compression */
nandgate	0:6dee052a3fa4	512	if ((n & 0xc0) == 0xc0) {
nandgate	0:6dee052a3fa4	513	/* Compressed name */
nandgate	0:6dee052a3fa4	514	break;
nandgate	0:6dee052a3fa4	515	} else {
nandgate	0:6dee052a3fa4	516	/* Not compressed name */
nandgate	0:6dee052a3fa4	517	while (n > 0) {
nandgate	0:6dee052a3fa4	518	if ((query) != (response)) {
nandgate	0:6dee052a3fa4	519	return 1;
nandgate	0:6dee052a3fa4	520	}
nandgate	0:6dee052a3fa4	521	++response;
nandgate	0:6dee052a3fa4	522	++query;
nandgate	0:6dee052a3fa4	523	--n;
nandgate	0:6dee052a3fa4	524	};
nandgate	0:6dee052a3fa4	525	++query;
nandgate	0:6dee052a3fa4	526	}
nandgate	0:6dee052a3fa4	527	} while (*response != 0);
nandgate	0:6dee052a3fa4	528
nandgate	0:6dee052a3fa4	529	return 0;
nandgate	0:6dee052a3fa4	530	}
nandgate	0:6dee052a3fa4	531	#endif /* DNS_DOES_NAME_CHECK */
nandgate	0:6dee052a3fa4	532
nandgate	0:6dee052a3fa4	533	/**
nandgate	0:6dee052a3fa4	534	* Walk through a compact encoded DNS name and return the end of the name.
nandgate	0:6dee052a3fa4	535	*
nandgate	0:6dee052a3fa4	536	* @param query encoded DNS name in the DNS server response
nandgate	0:6dee052a3fa4	537	* @return end of the name
nandgate	0:6dee052a3fa4	538	*/
nandgate	0:6dee052a3fa4	539	static unsigned char *
nandgate	0:6dee052a3fa4	540	dns_parse_name(unsigned char *query)
nandgate	0:6dee052a3fa4	541	{
nandgate	0:6dee052a3fa4	542	unsigned char n;
nandgate	0:6dee052a3fa4	543
nandgate	0:6dee052a3fa4	544	do {
nandgate	0:6dee052a3fa4	545	n = *query++;
nandgate	0:6dee052a3fa4	546	/** @see RFC 1035 - 4.1.4. Message compression */
nandgate	0:6dee052a3fa4	547	if ((n & 0xc0) == 0xc0) {
nandgate	0:6dee052a3fa4	548	/* Compressed name */
nandgate	0:6dee052a3fa4	549	break;
nandgate	0:6dee052a3fa4	550	} else {
nandgate	0:6dee052a3fa4	551	/* Not compressed name */
nandgate	0:6dee052a3fa4	552	while (n > 0) {
nandgate	0:6dee052a3fa4	553	++query;
nandgate	0:6dee052a3fa4	554	--n;
nandgate	0:6dee052a3fa4	555	};
nandgate	0:6dee052a3fa4	556	}
nandgate	0:6dee052a3fa4	557	} while (*query != 0);
nandgate	0:6dee052a3fa4	558
nandgate	0:6dee052a3fa4	559	return query + 1;
nandgate	0:6dee052a3fa4	560	}
nandgate	0:6dee052a3fa4	561
nandgate	0:6dee052a3fa4	562	/**
nandgate	0:6dee052a3fa4	563	* Send a DNS query packet.
nandgate	0:6dee052a3fa4	564	*
nandgate	0:6dee052a3fa4	565	* @param numdns index of the DNS server in the dns_servers table
nandgate	0:6dee052a3fa4	566	* @param name hostname to query
nandgate	0:6dee052a3fa4	567	* @param id index of the hostname in dns_table, used as transaction ID in the
nandgate	0:6dee052a3fa4	568	* DNS query packet
nandgate	0:6dee052a3fa4	569	* @return ERR_OK if packet is sent; an err_t indicating the problem otherwise
nandgate	0:6dee052a3fa4	570	*/
nandgate	0:6dee052a3fa4	571	static err_t
nandgate	0:6dee052a3fa4	572	dns_send(u8_t numdns, const char* name, u8_t id)
nandgate	0:6dee052a3fa4	573	{
nandgate	0:6dee052a3fa4	574	err_t err;
nandgate	0:6dee052a3fa4	575	struct dns_hdr *hdr;
nandgate	0:6dee052a3fa4	576	struct dns_query qry;
nandgate	0:6dee052a3fa4	577	struct pbuf *p;
nandgate	0:6dee052a3fa4	578	char query, nptr;
nandgate	0:6dee052a3fa4	579	const char *pHostname;
nandgate	0:6dee052a3fa4	580	u8_t n;
nandgate	0:6dee052a3fa4	581
nandgate	0:6dee052a3fa4	582	LWIP_DEBUGF(DNS_DEBUG, ("dns_send: dns_servers[%"U16_F"] \"%s\": request\n",
nandgate	0:6dee052a3fa4	583	(u16_t)(numdns), name));
nandgate	0:6dee052a3fa4	584	LWIP_ASSERT("dns server out of array", numdns < DNS_MAX_SERVERS);
nandgate	0:6dee052a3fa4	585	LWIP_ASSERT("dns server has no IP address set", dns_servers[numdns].addr != 0);
nandgate	0:6dee052a3fa4	586
nandgate	0:6dee052a3fa4	587	/* if here, we have either a new query or a retry on a previous query to process */
nandgate	0:6dee052a3fa4	588	p = pbuf_alloc(PBUF_TRANSPORT, SIZEOF_DNS_HDR + DNS_MAX_NAME_LENGTH +
nandgate	0:6dee052a3fa4	589	SIZEOF_DNS_QUERY, PBUF_RAM);
nandgate	0:6dee052a3fa4	590	if (p != NULL) {
nandgate	0:6dee052a3fa4	591	LWIP_ASSERT("pbuf must be in one piece", p->next == NULL);
nandgate	0:6dee052a3fa4	592	/* fill dns header */
nandgate	0:6dee052a3fa4	593	hdr = (struct dns_hdr*)p->payload;
nandgate	0:6dee052a3fa4	594	memset(hdr, 0, SIZEOF_DNS_HDR);
nandgate	0:6dee052a3fa4	595	hdr->id = htons(id);
nandgate	0:6dee052a3fa4	596	hdr->flags1 = DNS_FLAG1_RD;
nandgate	0:6dee052a3fa4	597	hdr->numquestions = htons(1);
nandgate	0:6dee052a3fa4	598	query = (char*)hdr + SIZEOF_DNS_HDR;
nandgate	0:6dee052a3fa4	599	pHostname = name;
nandgate	0:6dee052a3fa4	600	--pHostname;
nandgate	0:6dee052a3fa4	601
nandgate	0:6dee052a3fa4	602	/* convert hostname into suitable query format. */
nandgate	0:6dee052a3fa4	603	do {
nandgate	0:6dee052a3fa4	604	++pHostname;
nandgate	0:6dee052a3fa4	605	nptr = query;
nandgate	0:6dee052a3fa4	606	++query;
nandgate	0:6dee052a3fa4	607	for(n = 0; pHostname != '.' && pHostname != 0; ++pHostname) {
nandgate	0:6dee052a3fa4	608	query = pHostname;
nandgate	0:6dee052a3fa4	609	++query;
nandgate	0:6dee052a3fa4	610	++n;
nandgate	0:6dee052a3fa4	611	}
nandgate	0:6dee052a3fa4	612	*nptr = n;
nandgate	0:6dee052a3fa4	613	} while(*pHostname != 0);
nandgate	0:6dee052a3fa4	614	*query++='\0';
nandgate	0:6dee052a3fa4	615
nandgate	0:6dee052a3fa4	616	/* fill dns query */
nandgate	0:6dee052a3fa4	617	qry.type = htons(DNS_RRTYPE_A);
nandgate	0:6dee052a3fa4	618	qry.class = htons(DNS_RRCLASS_IN);
nandgate	0:6dee052a3fa4	619	MEMCPY( query, &qry, SIZEOF_DNS_QUERY);
nandgate	0:6dee052a3fa4	620
nandgate	0:6dee052a3fa4	621	/* resize pbuf to the exact dns query */
nandgate	0:6dee052a3fa4	622	pbuf_realloc(p, (query + SIZEOF_DNS_QUERY) - ((char*)(p->payload)));
nandgate	0:6dee052a3fa4	623
nandgate	0:6dee052a3fa4	624	/* connect to the server for faster receiving */
nandgate	0:6dee052a3fa4	625	udp_connect(dns_pcb, &dns_servers[numdns], DNS_SERVER_PORT);
nandgate	0:6dee052a3fa4	626	/* send dns packet */
nandgate	0:6dee052a3fa4	627	err = udp_sendto(dns_pcb, p, &dns_servers[numdns], DNS_SERVER_PORT);
nandgate	0:6dee052a3fa4	628
nandgate	0:6dee052a3fa4	629	/* free pbuf */
nandgate	0:6dee052a3fa4	630	pbuf_free(p);
nandgate	0:6dee052a3fa4	631	} else {
nandgate	0:6dee052a3fa4	632	err = ERR_MEM;
nandgate	0:6dee052a3fa4	633	}
nandgate	0:6dee052a3fa4	634
nandgate	0:6dee052a3fa4	635	return err;
nandgate	0:6dee052a3fa4	636	}
nandgate	0:6dee052a3fa4	637
nandgate	0:6dee052a3fa4	638	/**
nandgate	0:6dee052a3fa4	639	* dns_check_entry() - see if pEntry has not yet been queried and, if so, sends out a query.
nandgate	0:6dee052a3fa4	640	* Check an entry in the dns_table:
nandgate	0:6dee052a3fa4	641	* - send out query for new entries
nandgate	0:6dee052a3fa4	642	* - retry old pending entries on timeout (also with different servers)
nandgate	0:6dee052a3fa4	643	* - remove completed entries from the table if their TTL has expired
nandgate	0:6dee052a3fa4	644	*
nandgate	0:6dee052a3fa4	645	* @param i index of the dns_table entry to check
nandgate	0:6dee052a3fa4	646	*/
nandgate	0:6dee052a3fa4	647	static void
nandgate	0:6dee052a3fa4	648	dns_check_entry(u8_t i)
nandgate	0:6dee052a3fa4	649	{
nandgate	0:6dee052a3fa4	650	struct dns_table_entry *pEntry = &dns_table[i];
nandgate	0:6dee052a3fa4	651
nandgate	0:6dee052a3fa4	652	LWIP_ASSERT("array index out of bounds", i < DNS_TABLE_SIZE);
nandgate	0:6dee052a3fa4	653
nandgate	0:6dee052a3fa4	654	switch(pEntry->state) {
nandgate	0:6dee052a3fa4	655
nandgate	0:6dee052a3fa4	656	case DNS_STATE_NEW: {
nandgate	0:6dee052a3fa4	657	/* initialize new entry */
nandgate	0:6dee052a3fa4	658	pEntry->state = DNS_STATE_ASKING;
nandgate	0:6dee052a3fa4	659	pEntry->numdns = 0;
nandgate	0:6dee052a3fa4	660	pEntry->tmr = 1;
nandgate	0:6dee052a3fa4	661	pEntry->retries = 0;
nandgate	0:6dee052a3fa4	662
nandgate	0:6dee052a3fa4	663	/* send DNS packet for this entry */
nandgate	0:6dee052a3fa4	664	dns_send(pEntry->numdns, pEntry->name, i);
nandgate	0:6dee052a3fa4	665	break;
nandgate	0:6dee052a3fa4	666	}
nandgate	0:6dee052a3fa4	667
nandgate	0:6dee052a3fa4	668	case DNS_STATE_ASKING: {
nandgate	0:6dee052a3fa4	669	if (--pEntry->tmr == 0) {
nandgate	0:6dee052a3fa4	670	if (++pEntry->retries == DNS_MAX_RETRIES) {
nandgate	0:6dee052a3fa4	671	if ((pEntry->numdns+1<DNS_MAX_SERVERS) && (dns_servers[pEntry->numdns+1].addr!=0)) {
nandgate	0:6dee052a3fa4	672	/* change of server */
nandgate	0:6dee052a3fa4	673	pEntry->numdns++;
nandgate	0:6dee052a3fa4	674	pEntry->tmr = 1;
nandgate	0:6dee052a3fa4	675	pEntry->retries = 0;
nandgate	0:6dee052a3fa4	676	break;
nandgate	0:6dee052a3fa4	677	} else {
nandgate	0:6dee052a3fa4	678	LWIP_DEBUGF(DNS_DEBUG, ("dns_check_entry: \"%s\": timeout\n", pEntry->name));
nandgate	0:6dee052a3fa4	679	/* call specified callback function if provided */
nandgate	0:6dee052a3fa4	680	if (pEntry->found)
nandgate	0:6dee052a3fa4	681	(*pEntry->found)(pEntry->name, NULL, pEntry->arg);
nandgate	0:6dee052a3fa4	682	/* flush this entry */
nandgate	0:6dee052a3fa4	683	pEntry->state = DNS_STATE_UNUSED;
nandgate	0:6dee052a3fa4	684	pEntry->found = NULL;
nandgate	0:6dee052a3fa4	685	break;
nandgate	0:6dee052a3fa4	686	}
nandgate	0:6dee052a3fa4	687	}
nandgate	0:6dee052a3fa4	688
nandgate	0:6dee052a3fa4	689	/* wait longer for the next retry */
nandgate	0:6dee052a3fa4	690	pEntry->tmr = pEntry->retries;
nandgate	0:6dee052a3fa4	691
nandgate	0:6dee052a3fa4	692	/* send DNS packet for this entry */
nandgate	0:6dee052a3fa4	693	dns_send(pEntry->numdns, pEntry->name, i);
nandgate	0:6dee052a3fa4	694	}
nandgate	0:6dee052a3fa4	695	break;
nandgate	0:6dee052a3fa4	696	}
nandgate	0:6dee052a3fa4	697
nandgate	0:6dee052a3fa4	698	case DNS_STATE_DONE: {
nandgate	0:6dee052a3fa4	699	/* if the time to live is nul */
nandgate	0:6dee052a3fa4	700	if (--pEntry->ttl == 0) {
nandgate	0:6dee052a3fa4	701	LWIP_DEBUGF(DNS_DEBUG, ("dns_check_entry: \"%s\": flush\n", pEntry->name));
nandgate	0:6dee052a3fa4	702	/* flush this entry */
nandgate	0:6dee052a3fa4	703	pEntry->state = DNS_STATE_UNUSED;
nandgate	0:6dee052a3fa4	704	pEntry->found = NULL;
nandgate	0:6dee052a3fa4	705	}
nandgate	0:6dee052a3fa4	706	break;
nandgate	0:6dee052a3fa4	707	}
nandgate	0:6dee052a3fa4	708	case DNS_STATE_UNUSED:
nandgate	0:6dee052a3fa4	709	/* nothing to do */
nandgate	0:6dee052a3fa4	710	break;
nandgate	0:6dee052a3fa4	711	default:
nandgate	0:6dee052a3fa4	712	LWIP_ASSERT("unknown dns_table entry state:", 0);
nandgate	0:6dee052a3fa4	713	break;
nandgate	0:6dee052a3fa4	714	}
nandgate	0:6dee052a3fa4	715	}
nandgate	0:6dee052a3fa4	716
nandgate	0:6dee052a3fa4	717	/**
nandgate	0:6dee052a3fa4	718	* Call dns_check_entry for each entry in dns_table - check all entries.
nandgate	0:6dee052a3fa4	719	*/
nandgate	0:6dee052a3fa4	720	static void
nandgate	0:6dee052a3fa4	721	dns_check_entries(void)
nandgate	0:6dee052a3fa4	722	{
nandgate	0:6dee052a3fa4	723	u8_t i;
nandgate	0:6dee052a3fa4	724
nandgate	0:6dee052a3fa4	725	for (i = 0; i < DNS_TABLE_SIZE; ++i) {
nandgate	0:6dee052a3fa4	726	dns_check_entry(i);
nandgate	0:6dee052a3fa4	727	}
nandgate	0:6dee052a3fa4	728	}
nandgate	0:6dee052a3fa4	729
nandgate	0:6dee052a3fa4	730	/**
nandgate	0:6dee052a3fa4	731	* Receive input function for DNS response packets arriving for the dns UDP pcb.
nandgate	0:6dee052a3fa4	732	*
nandgate	0:6dee052a3fa4	733	* @params see udp.h
nandgate	0:6dee052a3fa4	734	*/
nandgate	0:6dee052a3fa4	735	static void
nandgate	0:6dee052a3fa4	736	dns_recv(void arg, struct udp_pcb pcb, struct pbuf p, struct ip_addr addr, u16_t port)
nandgate	0:6dee052a3fa4	737	{
nandgate	0:6dee052a3fa4	738	u8_t i;
nandgate	0:6dee052a3fa4	739	char *pHostname;
nandgate	0:6dee052a3fa4	740	struct dns_hdr *hdr;
nandgate	0:6dee052a3fa4	741	struct dns_answer ans;
nandgate	0:6dee052a3fa4	742	struct dns_table_entry *pEntry;
nandgate	0:6dee052a3fa4	743	u8_t nquestions, nanswers;
nandgate	0:6dee052a3fa4	744	#if (DNS_USES_STATIC_BUF == 0)
nandgate	0:6dee052a3fa4	745	u8_t dns_payload[DNS_MSG_SIZE];
nandgate	0:6dee052a3fa4	746	#endif /* (DNS_USES_STATIC_BUF == 0) */
nandgate	0:6dee052a3fa4	747	#if (DNS_USES_STATIC_BUF == 2)
nandgate	0:6dee052a3fa4	748	u8_t* dns_payload;
nandgate	0:6dee052a3fa4	749	#endif /* (DNS_USES_STATIC_BUF == 2) */
nandgate	0:6dee052a3fa4	750
nandgate	0:6dee052a3fa4	751	LWIP_UNUSED_ARG(arg);
nandgate	0:6dee052a3fa4	752	LWIP_UNUSED_ARG(pcb);
nandgate	0:6dee052a3fa4	753	LWIP_UNUSED_ARG(addr);
nandgate	0:6dee052a3fa4	754	LWIP_UNUSED_ARG(port);
nandgate	0:6dee052a3fa4	755
nandgate	0:6dee052a3fa4	756	/* is the dns message too big ? */
nandgate	0:6dee052a3fa4	757	if (p->tot_len > DNS_MSG_SIZE) {
nandgate	0:6dee052a3fa4	758	LWIP_DEBUGF(DNS_DEBUG, ("dns_recv: pbuf too big\n"));
nandgate	0:6dee052a3fa4	759	/* free pbuf and return */
nandgate	0:6dee052a3fa4	760	goto memerr1;
nandgate	0:6dee052a3fa4	761	}
nandgate	0:6dee052a3fa4	762
nandgate	0:6dee052a3fa4	763	/* is the dns message big enough ? */
nandgate	0:6dee052a3fa4	764	if (p->tot_len < (SIZEOF_DNS_HDR + SIZEOF_DNS_QUERY + SIZEOF_DNS_ANSWER)) {
nandgate	0:6dee052a3fa4	765	LWIP_DEBUGF(DNS_DEBUG, ("dns_recv: pbuf too small\n"));
nandgate	0:6dee052a3fa4	766	/* free pbuf and return */
nandgate	0:6dee052a3fa4	767	goto memerr1;
nandgate	0:6dee052a3fa4	768	}
nandgate	0:6dee052a3fa4	769
nandgate	0:6dee052a3fa4	770	#if (DNS_USES_STATIC_BUF == 2)
nandgate	0:6dee052a3fa4	771	dns_payload = mem_malloc(p->tot_len);
nandgate	0:6dee052a3fa4	772	if (dns_payload == NULL) {
nandgate	0:6dee052a3fa4	773	LWIP_DEBUGF(DNS_DEBUG, ("dns_recv: mem_malloc error\n"));
nandgate	0:6dee052a3fa4	774	/* free pbuf and return */
nandgate	0:6dee052a3fa4	775	goto memerr1;
nandgate	0:6dee052a3fa4	776	}
nandgate	0:6dee052a3fa4	777	#endif /* (DNS_USES_STATIC_BUF == 2) */
nandgate	0:6dee052a3fa4	778
nandgate	0:6dee052a3fa4	779	/* copy dns payload inside static buffer for processing */
nandgate	0:6dee052a3fa4	780	if (pbuf_copy_partial(p, dns_payload, p->tot_len, 0) == p->tot_len) {
nandgate	0:6dee052a3fa4	781	/* The ID in the DNS header should be our entry into the name table. */
nandgate	0:6dee052a3fa4	782	hdr = (struct dns_hdr*)dns_payload;
nandgate	0:6dee052a3fa4	783	i = htons(hdr->id);
nandgate	0:6dee052a3fa4	784	if (i < DNS_TABLE_SIZE) {
nandgate	0:6dee052a3fa4	785	pEntry = &dns_table[i];
nandgate	0:6dee052a3fa4	786	if(pEntry->state == DNS_STATE_ASKING) {
nandgate	0:6dee052a3fa4	787	/* This entry is now completed. */
nandgate	0:6dee052a3fa4	788	pEntry->state = DNS_STATE_DONE;
nandgate	0:6dee052a3fa4	789	pEntry->err = hdr->flags2 & DNS_FLAG2_ERR_MASK;
nandgate	0:6dee052a3fa4	790
nandgate	0:6dee052a3fa4	791	/* We only care about the question(s) and the answers. The authrr
nandgate	0:6dee052a3fa4	792	and the extrarr are simply discarded. */
nandgate	0:6dee052a3fa4	793	nquestions = htons(hdr->numquestions);
nandgate	0:6dee052a3fa4	794	nanswers = htons(hdr->numanswers);
nandgate	0:6dee052a3fa4	795
nandgate	0:6dee052a3fa4	796	/* Check for error. If so, call callback to inform. */
nandgate	0:6dee052a3fa4	797	if (((hdr->flags1 & DNS_FLAG1_RESPONSE) == 0) \|\| (pEntry->err != 0) \|\| (nquestions != 1)) {
nandgate	0:6dee052a3fa4	798	LWIP_DEBUGF(DNS_DEBUG, ("dns_recv: \"%s\": error in flags\n", pEntry->name));
nandgate	0:6dee052a3fa4	799	/* call callback to indicate error, clean up memory and return */
nandgate	0:6dee052a3fa4	800	goto responseerr;
nandgate	0:6dee052a3fa4	801	}
nandgate	0:6dee052a3fa4	802
nandgate	0:6dee052a3fa4	803	#if DNS_DOES_NAME_CHECK
nandgate	0:6dee052a3fa4	804	/* Check if the name in the "question" part match with the name in the entry. */
nandgate	0:6dee052a3fa4	805	if (dns_compare_name((unsigned char )(pEntry->name), (unsigned char )dns_payload + SIZEOF_DNS_HDR) != 0) {
nandgate	0:6dee052a3fa4	806	LWIP_DEBUGF(DNS_DEBUG, ("dns_recv: \"%s\": response not match to query\n", pEntry->name));
nandgate	0:6dee052a3fa4	807	/* call callback to indicate error, clean up memory and return */
nandgate	0:6dee052a3fa4	808	goto responseerr;
nandgate	0:6dee052a3fa4	809	}
nandgate	0:6dee052a3fa4	810	#endif /* DNS_DOES_NAME_CHECK */
nandgate	0:6dee052a3fa4	811
nandgate	0:6dee052a3fa4	812	/* Skip the name in the "question" part */
nandgate	0:6dee052a3fa4	813	pHostname = (char ) dns_parse_name((unsigned char )dns_payload + SIZEOF_DNS_HDR) + SIZEOF_DNS_QUERY;
nandgate	0:6dee052a3fa4	814
nandgate	0:6dee052a3fa4	815	while(nanswers > 0) {
nandgate	0:6dee052a3fa4	816	/* skip answer resource record's host name */
nandgate	0:6dee052a3fa4	817	pHostname = (char ) dns_parse_name((unsigned char )pHostname);
nandgate	0:6dee052a3fa4	818
nandgate	0:6dee052a3fa4	819	/* Check for IP address type and Internet class. Others are discarded. */
nandgate	0:6dee052a3fa4	820	MEMCPY(&ans, pHostname, SIZEOF_DNS_ANSWER);
nandgate	0:6dee052a3fa4	821	if((ntohs(ans.type) == DNS_RRTYPE_A) && (ntohs(ans.class) == DNS_RRCLASS_IN) && (ntohs(ans.len) == sizeof(struct ip_addr)) ) {
nandgate	0:6dee052a3fa4	822	/* read the answer resource record's TTL, and maximize it if needed */
nandgate	0:6dee052a3fa4	823	pEntry->ttl = ntohl(ans.ttl);
nandgate	0:6dee052a3fa4	824	if (pEntry->ttl > DNS_MAX_TTL) {
nandgate	0:6dee052a3fa4	825	pEntry->ttl = DNS_MAX_TTL;
nandgate	0:6dee052a3fa4	826	}
nandgate	0:6dee052a3fa4	827	/* read the IP address after answer resource record's header */
nandgate	0:6dee052a3fa4	828	MEMCPY( &(pEntry->ipaddr), (pHostname+SIZEOF_DNS_ANSWER), sizeof(struct ip_addr));
nandgate	0:6dee052a3fa4	829	LWIP_DEBUGF(DNS_DEBUG, ("dns_recv: \"%s\": response = ", pEntry->name));
nandgate	0:6dee052a3fa4	830	ip_addr_debug_print(DNS_DEBUG, (&(pEntry->ipaddr)));
nandgate	0:6dee052a3fa4	831	LWIP_DEBUGF(DNS_DEBUG, ("\n"));
nandgate	0:6dee052a3fa4	832	/* call specified callback function if provided */
nandgate	0:6dee052a3fa4	833	if (pEntry->found) {
nandgate	0:6dee052a3fa4	834	(*pEntry->found)(pEntry->name, &pEntry->ipaddr, pEntry->arg);
nandgate	0:6dee052a3fa4	835	}
nandgate	0:6dee052a3fa4	836	/* deallocate memory and return */
nandgate	0:6dee052a3fa4	837	goto memerr2;
nandgate	0:6dee052a3fa4	838	} else {
nandgate	0:6dee052a3fa4	839	pHostname = pHostname + SIZEOF_DNS_ANSWER + htons(ans.len);
nandgate	0:6dee052a3fa4	840	}
nandgate	0:6dee052a3fa4	841	--nanswers;
nandgate	0:6dee052a3fa4	842	}
nandgate	0:6dee052a3fa4	843	LWIP_DEBUGF(DNS_DEBUG, ("dns_recv: \"%s\": error in response\n", pEntry->name));
nandgate	0:6dee052a3fa4	844	/* call callback to indicate error, clean up memory and return */
nandgate	0:6dee052a3fa4	845	goto responseerr;
nandgate	0:6dee052a3fa4	846	}
nandgate	0:6dee052a3fa4	847	}
nandgate	0:6dee052a3fa4	848	}
nandgate	0:6dee052a3fa4	849
nandgate	0:6dee052a3fa4	850	/* deallocate memory and return */
nandgate	0:6dee052a3fa4	851	goto memerr2;
nandgate	0:6dee052a3fa4	852
nandgate	0:6dee052a3fa4	853	responseerr:
nandgate	0:6dee052a3fa4	854	/* ERROR: call specified callback function with NULL as name to indicate an error */
nandgate	0:6dee052a3fa4	855	if (pEntry->found) {
nandgate	0:6dee052a3fa4	856	(*pEntry->found)(pEntry->name, NULL, pEntry->arg);
nandgate	0:6dee052a3fa4	857	}
nandgate	0:6dee052a3fa4	858	/* flush this entry */
nandgate	0:6dee052a3fa4	859	pEntry->state = DNS_STATE_UNUSED;
nandgate	0:6dee052a3fa4	860	pEntry->found = NULL;
nandgate	0:6dee052a3fa4	861
nandgate	0:6dee052a3fa4	862	memerr2:
nandgate	0:6dee052a3fa4	863	#if (DNS_USES_STATIC_BUF == 2)
nandgate	0:6dee052a3fa4	864	/* free dns buffer */
nandgate	0:6dee052a3fa4	865	mem_free(dns_payload);
nandgate	0:6dee052a3fa4	866	#endif /* (DNS_USES_STATIC_BUF == 2) */
nandgate	0:6dee052a3fa4	867
nandgate	0:6dee052a3fa4	868	memerr1:
nandgate	0:6dee052a3fa4	869	/* free pbuf */
nandgate	0:6dee052a3fa4	870	pbuf_free(p);
nandgate	0:6dee052a3fa4	871	return;
nandgate	0:6dee052a3fa4	872	}
nandgate	0:6dee052a3fa4	873
nandgate	0:6dee052a3fa4	874	/**
nandgate	0:6dee052a3fa4	875	* Queues a new hostname to resolve and sends out a DNS query for that hostname
nandgate	0:6dee052a3fa4	876	*
nandgate	0:6dee052a3fa4	877	* @param name the hostname that is to be queried
nandgate	0:6dee052a3fa4	878	* @param found a callback founction to be called on success, failure or timeout
nandgate	0:6dee052a3fa4	879	* @param callback_arg argument to pass to the callback function
nandgate	0:6dee052a3fa4	880	* @return @return a err_t return code.
nandgate	0:6dee052a3fa4	881	*/
nandgate	0:6dee052a3fa4	882	static err_t
nandgate	0:6dee052a3fa4	883	dns_enqueue(const char name, dns_found_callback found, void callback_arg)
nandgate	0:6dee052a3fa4	884	{
nandgate	0:6dee052a3fa4	885	u8_t i;
nandgate	0:6dee052a3fa4	886	u8_t lseq, lseqi;
nandgate	0:6dee052a3fa4	887	struct dns_table_entry *pEntry = NULL;
nandgate	0:6dee052a3fa4	888
nandgate	0:6dee052a3fa4	889	/* search an unused entry, or the oldest one */
nandgate	0:6dee052a3fa4	890	lseq = lseqi = 0;
nandgate	0:6dee052a3fa4	891	for (i = 0; i < DNS_TABLE_SIZE; ++i) {
nandgate	0:6dee052a3fa4	892	pEntry = &dns_table[i];
nandgate	0:6dee052a3fa4	893	/* is it an unused entry ? */
nandgate	0:6dee052a3fa4	894	if (pEntry->state == DNS_STATE_UNUSED)
nandgate	0:6dee052a3fa4	895	break;
nandgate	0:6dee052a3fa4	896
nandgate	0:6dee052a3fa4	897	/* check if this is the oldest completed entry */
nandgate	0:6dee052a3fa4	898	if (pEntry->state == DNS_STATE_DONE) {
nandgate	0:6dee052a3fa4	899	if ((dns_seqno - pEntry->seqno) > lseq) {
nandgate	0:6dee052a3fa4	900	lseq = dns_seqno - pEntry->seqno;
nandgate	0:6dee052a3fa4	901	lseqi = i;
nandgate	0:6dee052a3fa4	902	}
nandgate	0:6dee052a3fa4	903	}
nandgate	0:6dee052a3fa4	904	}
nandgate	0:6dee052a3fa4	905
nandgate	0:6dee052a3fa4	906	/* if we don't have found an unused entry, use the oldest completed one */
nandgate	0:6dee052a3fa4	907	if (i == DNS_TABLE_SIZE) {
nandgate	0:6dee052a3fa4	908	if ((lseqi >= DNS_TABLE_SIZE) \|\| (dns_table[lseqi].state != DNS_STATE_DONE)) {
nandgate	0:6dee052a3fa4	909	/* no entry can't be used now, table is full */
nandgate	0:6dee052a3fa4	910	LWIP_DEBUGF(DNS_DEBUG, ("dns_enqueue: \"%s\": DNS entries table is full\n", name));
nandgate	0:6dee052a3fa4	911	return ERR_MEM;
nandgate	0:6dee052a3fa4	912	} else {
nandgate	0:6dee052a3fa4	913	/* use the oldest completed one */
nandgate	0:6dee052a3fa4	914	i = lseqi;
nandgate	0:6dee052a3fa4	915	pEntry = &dns_table[i];
nandgate	0:6dee052a3fa4	916	}
nandgate	0:6dee052a3fa4	917	}
nandgate	0:6dee052a3fa4	918
nandgate	0:6dee052a3fa4	919	/* use this entry */
nandgate	0:6dee052a3fa4	920	LWIP_DEBUGF(DNS_DEBUG, ("dns_enqueue: \"%s\": use DNS entry %"U16_F"\n", name, (u16_t)(i)));
nandgate	0:6dee052a3fa4	921
nandgate	0:6dee052a3fa4	922	/* fill the entry */
nandgate	0:6dee052a3fa4	923	pEntry->state = DNS_STATE_NEW;
nandgate	0:6dee052a3fa4	924	pEntry->seqno = dns_seqno++;
nandgate	0:6dee052a3fa4	925	pEntry->found = found;
nandgate	0:6dee052a3fa4	926	pEntry->arg = callback_arg;
nandgate	0:6dee052a3fa4	927	strcpy(pEntry->name, name);
nandgate	0:6dee052a3fa4	928
nandgate	0:6dee052a3fa4	929	/* force to send query without waiting timer */
nandgate	0:6dee052a3fa4	930	dns_check_entry(i);
nandgate	0:6dee052a3fa4	931
nandgate	0:6dee052a3fa4	932	/* dns query is enqueued */
nandgate	0:6dee052a3fa4	933	return ERR_INPROGRESS;
nandgate	0:6dee052a3fa4	934	}
nandgate	0:6dee052a3fa4	935
nandgate	0:6dee052a3fa4	936	/**
nandgate	0:6dee052a3fa4	937	* Resolve a hostname (string) into an IP address.
nandgate	0:6dee052a3fa4	938	* NON-BLOCKING callback version for use with raw API!!!
nandgate	0:6dee052a3fa4	939	*
nandgate	0:6dee052a3fa4	940	* Returns immediately with one of err_t return codes:
nandgate	0:6dee052a3fa4	941	* - ERR_OK if hostname is a valid IP address string or the host
nandgate	0:6dee052a3fa4	942	* name is already in the local names table.
nandgate	0:6dee052a3fa4	943	* - ERR_INPROGRESS enqueue a request to be sent to the DNS server
nandgate	0:6dee052a3fa4	944	* for resolution if no errors are present.
nandgate	0:6dee052a3fa4	945	*
nandgate	0:6dee052a3fa4	946	* @param hostname the hostname that is to be queried
nandgate	0:6dee052a3fa4	947	* @param addr pointer to a struct ip_addr where to store the address if it is already
nandgate	0:6dee052a3fa4	948	* cached in the dns_table (only valid if ERR_OK is returned!)
nandgate	0:6dee052a3fa4	949	* @param found a callback function to be called on success, failure or timeout (only if
nandgate	0:6dee052a3fa4	950	* ERR_INPROGRESS is returned!)
nandgate	0:6dee052a3fa4	951	* @param callback_arg argument to pass to the callback function
nandgate	0:6dee052a3fa4	952	* @return a err_t return code.
nandgate	0:6dee052a3fa4	953	*/
nandgate	0:6dee052a3fa4	954	err_t
nandgate	0:6dee052a3fa4	955	dns_gethostbyname(const char hostname, struct ip_addr addr, dns_found_callback found,
nandgate	0:6dee052a3fa4	956	void *callback_arg)
nandgate	0:6dee052a3fa4	957	{
nandgate	0:6dee052a3fa4	958	/* not initialized or no valid server yet, or invalid addr pointer
nandgate	0:6dee052a3fa4	959	* or invalid hostname or invalid hostname length */
nandgate	0:6dee052a3fa4	960	if ((dns_pcb == NULL) \|\| (addr == NULL) \|\|
nandgate	0:6dee052a3fa4	961	(!hostname) \|\| (!hostname[0]) \|\|
nandgate	0:6dee052a3fa4	962	(strlen(hostname) >= DNS_MAX_NAME_LENGTH)) {
nandgate	0:6dee052a3fa4	963	return ERR_VAL;
nandgate	0:6dee052a3fa4	964	}
nandgate	0:6dee052a3fa4	965
nandgate	0:6dee052a3fa4	966	#if LWIP_HAVE_LOOPIF
nandgate	0:6dee052a3fa4	967	if (strcmp(hostname,"localhost")==0) {
nandgate	0:6dee052a3fa4	968	addr->addr = htonl(INADDR_LOOPBACK);
nandgate	0:6dee052a3fa4	969	return ERR_OK;
nandgate	0:6dee052a3fa4	970	}
nandgate	0:6dee052a3fa4	971	#endif /* LWIP_HAVE_LOOPIF */
nandgate	0:6dee052a3fa4	972
nandgate	0:6dee052a3fa4	973	/* host name already in octet notation? set ip addr and return ERR_OK
nandgate	0:6dee052a3fa4	974	* already have this address cached? */
nandgate	0:6dee052a3fa4	975	if (((addr->addr = inet_addr(hostname)) != INADDR_NONE) \|\|
nandgate	0:6dee052a3fa4	976	((addr->addr = dns_lookup(hostname)) != INADDR_NONE)) {
nandgate	0:6dee052a3fa4	977	return ERR_OK;
nandgate	0:6dee052a3fa4	978	}
nandgate	0:6dee052a3fa4	979
nandgate	0:6dee052a3fa4	980	/* queue query with specified callback */
nandgate	0:6dee052a3fa4	981	return dns_enqueue(hostname, found, callback_arg);
nandgate	0:6dee052a3fa4	982	}
nandgate	0:6dee052a3fa4	983
nandgate	0:6dee052a3fa4	984	#endif /* LWIP_DNS */

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Type:	Program
Mbed OS support:	Mbed 2 deprecated
Created:	26 Jul 2011
Imports:	159
Forks:	0
Commits:	1
Dependents:	0
Dependencies:	2
Followers:	9

Core/lwIP/core/dns.c@0:6dee052a3fa4, 2011-07-26 (annotated)

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