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NetStack/lwip/core/dns.c@0:616601bde9fb, 2012-02-23 (annotated)

Committer:: AdamGreen
Date:: Thu Feb 23 21:38:39 2012 +0000
Revision:: 0:616601bde9fb

Who changed what in which revision?

User	Revision	Line number	New contents of line
AdamGreen	0:616601bde9fb	1	/**
AdamGreen	0:616601bde9fb	2	* @file
AdamGreen	0:616601bde9fb	3	* DNS - host name to IP address resolver.
AdamGreen	0:616601bde9fb	4	*
AdamGreen	0:616601bde9fb	5	*/
AdamGreen	0:616601bde9fb	6
AdamGreen	0:616601bde9fb	7	/**
AdamGreen	0:616601bde9fb	8
AdamGreen	0:616601bde9fb	9	* This file implements a DNS host name to IP address resolver.
AdamGreen	0:616601bde9fb	10
AdamGreen	0:616601bde9fb	11	* Port to lwIP from uIP
AdamGreen	0:616601bde9fb	12	* by Jim Pettinato April 2007
AdamGreen	0:616601bde9fb	13
AdamGreen	0:616601bde9fb	14	* uIP version Copyright (c) 2002-2003, Adam Dunkels.
AdamGreen	0:616601bde9fb	15	* All rights reserved.
AdamGreen	0:616601bde9fb	16	*
AdamGreen	0:616601bde9fb	17	* Redistribution and use in source and binary forms, with or without
AdamGreen	0:616601bde9fb	18	* modification, are permitted provided that the following conditions
AdamGreen	0:616601bde9fb	19	* are met:
AdamGreen	0:616601bde9fb	20	* 1. Redistributions of source code must retain the above copyright
AdamGreen	0:616601bde9fb	21	* notice, this list of conditions and the following disclaimer.
AdamGreen	0:616601bde9fb	22	* 2. Redistributions in binary form must reproduce the above copyright
AdamGreen	0:616601bde9fb	23	* notice, this list of conditions and the following disclaimer in the
AdamGreen	0:616601bde9fb	24	* documentation and/or other materials provided with the distribution.
AdamGreen	0:616601bde9fb	25	* 3. The name of the author may not be used to endorse or promote
AdamGreen	0:616601bde9fb	26	* products derived from this software without specific prior
AdamGreen	0:616601bde9fb	27	* written permission.
AdamGreen	0:616601bde9fb	28	*
AdamGreen	0:616601bde9fb	29	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
AdamGreen	0:616601bde9fb	30	* OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
AdamGreen	0:616601bde9fb	31	* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
AdamGreen	0:616601bde9fb	32	* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
AdamGreen	0:616601bde9fb	33	* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
AdamGreen	0:616601bde9fb	34	* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
AdamGreen	0:616601bde9fb	35	* GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
AdamGreen	0:616601bde9fb	36	* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
AdamGreen	0:616601bde9fb	37	* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
AdamGreen	0:616601bde9fb	38	* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
AdamGreen	0:616601bde9fb	39	* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
AdamGreen	0:616601bde9fb	40	*
AdamGreen	0:616601bde9fb	41	*
AdamGreen	0:616601bde9fb	42	* DNS.C
AdamGreen	0:616601bde9fb	43	*
AdamGreen	0:616601bde9fb	44	* The lwIP DNS resolver functions are used to lookup a host name and
AdamGreen	0:616601bde9fb	45	* map it to a numerical IP address. It maintains a list of resolved
AdamGreen	0:616601bde9fb	46	* hostnames that can be queried with the dns_lookup() function.
AdamGreen	0:616601bde9fb	47	* New hostnames can be resolved using the dns_query() function.
AdamGreen	0:616601bde9fb	48	*
AdamGreen	0:616601bde9fb	49	* The lwIP version of the resolver also adds a non-blocking version of
AdamGreen	0:616601bde9fb	50	* gethostbyname() that will work with a raw API application. This function
AdamGreen	0:616601bde9fb	51	* checks for an IP address string first and converts it if it is valid.
AdamGreen	0:616601bde9fb	52	* gethostbyname() then does a dns_lookup() to see if the name is
AdamGreen	0:616601bde9fb	53	* already in the table. If so, the IP is returned. If not, a query is
AdamGreen	0:616601bde9fb	54	* issued and the function returns with a ERR_INPROGRESS status. The app
AdamGreen	0:616601bde9fb	55	* using the dns client must then go into a waiting state.
AdamGreen	0:616601bde9fb	56	*
AdamGreen	0:616601bde9fb	57	* Once a hostname has been resolved (or found to be non-existent),
AdamGreen	0:616601bde9fb	58	* the resolver code calls a specified callback function (which
AdamGreen	0:616601bde9fb	59	* must be implemented by the module that uses the resolver).
AdamGreen	0:616601bde9fb	60	*/
AdamGreen	0:616601bde9fb	61
AdamGreen	0:616601bde9fb	62	/*-----------------------------------------------------------------------------
AdamGreen	0:616601bde9fb	63	* RFC 1035 - Domain names - implementation and specification
AdamGreen	0:616601bde9fb	64	* RFC 2181 - Clarifications to the DNS Specification
AdamGreen	0:616601bde9fb	65	----------------------------------------------------------------------------/
AdamGreen	0:616601bde9fb	66
AdamGreen	0:616601bde9fb	67	/** @todo: define good default values (rfc compliance) */
AdamGreen	0:616601bde9fb	68	/** @todo: improve answer parsing, more checkings... */
AdamGreen	0:616601bde9fb	69	/** @todo: check RFC1035 - 7.3. Processing responses */
AdamGreen	0:616601bde9fb	70
AdamGreen	0:616601bde9fb	71	/*-----------------------------------------------------------------------------
AdamGreen	0:616601bde9fb	72	* Includes
AdamGreen	0:616601bde9fb	73	----------------------------------------------------------------------------/
AdamGreen	0:616601bde9fb	74
AdamGreen	0:616601bde9fb	75	#include "lwip/opt.h"
AdamGreen	0:616601bde9fb	76
AdamGreen	0:616601bde9fb	77	#if LWIP_DNS /* don't build if not configured for use in lwipopts.h */
AdamGreen	0:616601bde9fb	78
AdamGreen	0:616601bde9fb	79	#include "lwip/udp.h"
AdamGreen	0:616601bde9fb	80	#include "lwip/mem.h"
AdamGreen	0:616601bde9fb	81	#include "lwip/memp.h"
AdamGreen	0:616601bde9fb	82	#include "lwip/dns.h"
AdamGreen	0:616601bde9fb	83
AdamGreen	0:616601bde9fb	84	#include <string.h>
AdamGreen	0:616601bde9fb	85
AdamGreen	0:616601bde9fb	86	/** DNS server IP address */
AdamGreen	0:616601bde9fb	87	#ifndef DNS_SERVER_ADDRESS
AdamGreen	0:616601bde9fb	88	#define DNS_SERVER_ADDRESS(ipaddr) (ip4_addr_set_u32(ipaddr, ipaddr_addr("208.67.222.222"))) /* resolver1.opendns.com */
AdamGreen	0:616601bde9fb	89	#endif
AdamGreen	0:616601bde9fb	90
AdamGreen	0:616601bde9fb	91	/** DNS server port address */
AdamGreen	0:616601bde9fb	92	#ifndef DNS_SERVER_PORT
AdamGreen	0:616601bde9fb	93	#define DNS_SERVER_PORT 53
AdamGreen	0:616601bde9fb	94	#endif
AdamGreen	0:616601bde9fb	95
AdamGreen	0:616601bde9fb	96	/** DNS maximum number of retries when asking for a name, before "timeout". */
AdamGreen	0:616601bde9fb	97	#ifndef DNS_MAX_RETRIES
AdamGreen	0:616601bde9fb	98	#define DNS_MAX_RETRIES 4
AdamGreen	0:616601bde9fb	99	#endif
AdamGreen	0:616601bde9fb	100
AdamGreen	0:616601bde9fb	101	/** DNS resource record max. TTL (one week as default) */
AdamGreen	0:616601bde9fb	102	#ifndef DNS_MAX_TTL
AdamGreen	0:616601bde9fb	103	#define DNS_MAX_TTL 604800
AdamGreen	0:616601bde9fb	104	#endif
AdamGreen	0:616601bde9fb	105
AdamGreen	0:616601bde9fb	106	/* DNS protocol flags */
AdamGreen	0:616601bde9fb	107	#define DNS_FLAG1_RESPONSE 0x80
AdamGreen	0:616601bde9fb	108	#define DNS_FLAG1_OPCODE_STATUS 0x10
AdamGreen	0:616601bde9fb	109	#define DNS_FLAG1_OPCODE_INVERSE 0x08
AdamGreen	0:616601bde9fb	110	#define DNS_FLAG1_OPCODE_STANDARD 0x00
AdamGreen	0:616601bde9fb	111	#define DNS_FLAG1_AUTHORATIVE 0x04
AdamGreen	0:616601bde9fb	112	#define DNS_FLAG1_TRUNC 0x02
AdamGreen	0:616601bde9fb	113	#define DNS_FLAG1_RD 0x01
AdamGreen	0:616601bde9fb	114	#define DNS_FLAG2_RA 0x80
AdamGreen	0:616601bde9fb	115	#define DNS_FLAG2_ERR_MASK 0x0f
AdamGreen	0:616601bde9fb	116	#define DNS_FLAG2_ERR_NONE 0x00
AdamGreen	0:616601bde9fb	117	#define DNS_FLAG2_ERR_NAME 0x03
AdamGreen	0:616601bde9fb	118
AdamGreen	0:616601bde9fb	119	/* DNS protocol states */
AdamGreen	0:616601bde9fb	120	#define DNS_STATE_UNUSED 0
AdamGreen	0:616601bde9fb	121	#define DNS_STATE_NEW 1
AdamGreen	0:616601bde9fb	122	#define DNS_STATE_ASKING 2
AdamGreen	0:616601bde9fb	123	#define DNS_STATE_DONE 3
AdamGreen	0:616601bde9fb	124
AdamGreen	0:616601bde9fb	125	#ifdef PACK_STRUCT_USE_INCLUDES
AdamGreen	0:616601bde9fb	126	# include "arch/bpstruct.h"
AdamGreen	0:616601bde9fb	127	#endif
AdamGreen	0:616601bde9fb	128	PACK_STRUCT_BEGIN
AdamGreen	0:616601bde9fb	129	/** DNS message header */
AdamGreen	0:616601bde9fb	130	struct dns_hdr {
AdamGreen	0:616601bde9fb	131	PACK_STRUCT_FIELD(u16_t id);
AdamGreen	0:616601bde9fb	132	PACK_STRUCT_FIELD(u8_t flags1);
AdamGreen	0:616601bde9fb	133	PACK_STRUCT_FIELD(u8_t flags2);
AdamGreen	0:616601bde9fb	134	PACK_STRUCT_FIELD(u16_t numquestions);
AdamGreen	0:616601bde9fb	135	PACK_STRUCT_FIELD(u16_t numanswers);
AdamGreen	0:616601bde9fb	136	PACK_STRUCT_FIELD(u16_t numauthrr);
AdamGreen	0:616601bde9fb	137	PACK_STRUCT_FIELD(u16_t numextrarr);
AdamGreen	0:616601bde9fb	138	} PACK_STRUCT_STRUCT;
AdamGreen	0:616601bde9fb	139	PACK_STRUCT_END
AdamGreen	0:616601bde9fb	140	#ifdef PACK_STRUCT_USE_INCLUDES
AdamGreen	0:616601bde9fb	141	# include "arch/epstruct.h"
AdamGreen	0:616601bde9fb	142	#endif
AdamGreen	0:616601bde9fb	143	#define SIZEOF_DNS_HDR 12
AdamGreen	0:616601bde9fb	144
AdamGreen	0:616601bde9fb	145	/** DNS query message structure.
AdamGreen	0:616601bde9fb	146	No packing needed: only used locally on the stack. */
AdamGreen	0:616601bde9fb	147	struct dns_query {
AdamGreen	0:616601bde9fb	148	/* DNS query record starts with either a domain name or a pointer
AdamGreen	0:616601bde9fb	149	to a name already present somewhere in the packet. */
AdamGreen	0:616601bde9fb	150	u16_t type;
AdamGreen	0:616601bde9fb	151	u16_t cls;
AdamGreen	0:616601bde9fb	152	};
AdamGreen	0:616601bde9fb	153	#define SIZEOF_DNS_QUERY 4
AdamGreen	0:616601bde9fb	154
AdamGreen	0:616601bde9fb	155	/** DNS answer message structure.
AdamGreen	0:616601bde9fb	156	No packing needed: only used locally on the stack. */
AdamGreen	0:616601bde9fb	157	struct dns_answer {
AdamGreen	0:616601bde9fb	158	/* DNS answer record starts with either a domain name or a pointer
AdamGreen	0:616601bde9fb	159	to a name already present somewhere in the packet. */
AdamGreen	0:616601bde9fb	160	u16_t type;
AdamGreen	0:616601bde9fb	161	u16_t cls;
AdamGreen	0:616601bde9fb	162	u32_t ttl;
AdamGreen	0:616601bde9fb	163	u16_t len;
AdamGreen	0:616601bde9fb	164	};
AdamGreen	0:616601bde9fb	165	#define SIZEOF_DNS_ANSWER 10
AdamGreen	0:616601bde9fb	166
AdamGreen	0:616601bde9fb	167	/** DNS table entry */
AdamGreen	0:616601bde9fb	168	struct dns_table_entry {
AdamGreen	0:616601bde9fb	169	u8_t state;
AdamGreen	0:616601bde9fb	170	u8_t numdns;
AdamGreen	0:616601bde9fb	171	u8_t tmr;
AdamGreen	0:616601bde9fb	172	u8_t retries;
AdamGreen	0:616601bde9fb	173	u8_t seqno;
AdamGreen	0:616601bde9fb	174	u8_t err;
AdamGreen	0:616601bde9fb	175	u32_t ttl;
AdamGreen	0:616601bde9fb	176	char name[DNS_MAX_NAME_LENGTH];
AdamGreen	0:616601bde9fb	177	ip_addr_t ipaddr;
AdamGreen	0:616601bde9fb	178	/* pointer to callback on DNS query done */
AdamGreen	0:616601bde9fb	179	dns_found_callback found;
AdamGreen	0:616601bde9fb	180	void *arg;
AdamGreen	0:616601bde9fb	181	};
AdamGreen	0:616601bde9fb	182
AdamGreen	0:616601bde9fb	183	#if DNS_LOCAL_HOSTLIST
AdamGreen	0:616601bde9fb	184
AdamGreen	0:616601bde9fb	185	#if DNS_LOCAL_HOSTLIST_IS_DYNAMIC
AdamGreen	0:616601bde9fb	186	/** Local host-list. For hostnames in this list, no
AdamGreen	0:616601bde9fb	187	* external name resolution is performed */
AdamGreen	0:616601bde9fb	188	static struct local_hostlist_entry *local_hostlist_dynamic;
AdamGreen	0:616601bde9fb	189	#else /* DNS_LOCAL_HOSTLIST_IS_DYNAMIC */
AdamGreen	0:616601bde9fb	190
AdamGreen	0:616601bde9fb	191	/** Defining this allows the local_hostlist_static to be placed in a different
AdamGreen	0:616601bde9fb	192	* linker section (e.g. FLASH) */
AdamGreen	0:616601bde9fb	193	#ifndef DNS_LOCAL_HOSTLIST_STORAGE_PRE
AdamGreen	0:616601bde9fb	194	#define DNS_LOCAL_HOSTLIST_STORAGE_PRE static
AdamGreen	0:616601bde9fb	195	#endif /* DNS_LOCAL_HOSTLIST_STORAGE_PRE */
AdamGreen	0:616601bde9fb	196	/** Defining this allows the local_hostlist_static to be placed in a different
AdamGreen	0:616601bde9fb	197	* linker section (e.g. FLASH) */
AdamGreen	0:616601bde9fb	198	#ifndef DNS_LOCAL_HOSTLIST_STORAGE_POST
AdamGreen	0:616601bde9fb	199	#define DNS_LOCAL_HOSTLIST_STORAGE_POST
AdamGreen	0:616601bde9fb	200	#endif /* DNS_LOCAL_HOSTLIST_STORAGE_POST */
AdamGreen	0:616601bde9fb	201	DNS_LOCAL_HOSTLIST_STORAGE_PRE struct local_hostlist_entry local_hostlist_static[]
AdamGreen	0:616601bde9fb	202	DNS_LOCAL_HOSTLIST_STORAGE_POST = DNS_LOCAL_HOSTLIST_INIT;
AdamGreen	0:616601bde9fb	203
AdamGreen	0:616601bde9fb	204	#endif /* DNS_LOCAL_HOSTLIST_IS_DYNAMIC */
AdamGreen	0:616601bde9fb	205
AdamGreen	0:616601bde9fb	206	static void dns_init_local();
AdamGreen	0:616601bde9fb	207	#endif /* DNS_LOCAL_HOSTLIST */
AdamGreen	0:616601bde9fb	208
AdamGreen	0:616601bde9fb	209
AdamGreen	0:616601bde9fb	210	/* forward declarations */
AdamGreen	0:616601bde9fb	211	static void dns_recv(void s, struct udp_pcb pcb, struct pbuf p, ip_addr_t addr, u16_t port);
AdamGreen	0:616601bde9fb	212	static void dns_check_entries(void);
AdamGreen	0:616601bde9fb	213
AdamGreen	0:616601bde9fb	214	/*-----------------------------------------------------------------------------
AdamGreen	0:616601bde9fb	215	* Globales
AdamGreen	0:616601bde9fb	216	----------------------------------------------------------------------------/
AdamGreen	0:616601bde9fb	217
AdamGreen	0:616601bde9fb	218	/* DNS variables */
AdamGreen	0:616601bde9fb	219	static struct udp_pcb *dns_pcb;
AdamGreen	0:616601bde9fb	220	static u8_t dns_seqno;
AdamGreen	0:616601bde9fb	221	static struct dns_table_entry dns_table[DNS_TABLE_SIZE];
AdamGreen	0:616601bde9fb	222	static ip_addr_t dns_servers[DNS_MAX_SERVERS];
AdamGreen	0:616601bde9fb	223	/** Contiguous buffer for processing responses */
AdamGreen	0:616601bde9fb	224	static u8_t dns_payload_buffer[LWIP_MEM_ALIGN_BUFFER(DNS_MSG_SIZE)];
AdamGreen	0:616601bde9fb	225	static u8_t* dns_payload;
AdamGreen	0:616601bde9fb	226
AdamGreen	0:616601bde9fb	227	/**
AdamGreen	0:616601bde9fb	228	* Initialize the resolver: set up the UDP pcb and configure the default server
AdamGreen	0:616601bde9fb	229	* (DNS_SERVER_ADDRESS).
AdamGreen	0:616601bde9fb	230	*/
AdamGreen	0:616601bde9fb	231	void
AdamGreen	0:616601bde9fb	232	dns_init()
AdamGreen	0:616601bde9fb	233	{
AdamGreen	0:616601bde9fb	234	ip_addr_t dnsserver;
AdamGreen	0:616601bde9fb	235
AdamGreen	0:616601bde9fb	236	dns_payload = (u8_t *)LWIP_MEM_ALIGN(dns_payload_buffer);
AdamGreen	0:616601bde9fb	237
AdamGreen	0:616601bde9fb	238	/* initialize default DNS server address */
AdamGreen	0:616601bde9fb	239	DNS_SERVER_ADDRESS(&dnsserver);
AdamGreen	0:616601bde9fb	240
AdamGreen	0:616601bde9fb	241	LWIP_DEBUGF(DNS_DEBUG, ("dns_init: initializing\n"));
AdamGreen	0:616601bde9fb	242
AdamGreen	0:616601bde9fb	243	/* if dns client not yet initialized... */
AdamGreen	0:616601bde9fb	244	if (dns_pcb == NULL) {
AdamGreen	0:616601bde9fb	245	dns_pcb = udp_new();
AdamGreen	0:616601bde9fb	246
AdamGreen	0:616601bde9fb	247	if (dns_pcb != NULL) {
AdamGreen	0:616601bde9fb	248	/* initialize DNS table not needed (initialized to zero since it is a
AdamGreen	0:616601bde9fb	249	* global variable) */
AdamGreen	0:616601bde9fb	250	LWIP_ASSERT("For implicit initialization to work, DNS_STATE_UNUSED needs to be 0",
AdamGreen	0:616601bde9fb	251	DNS_STATE_UNUSED == 0);
AdamGreen	0:616601bde9fb	252
AdamGreen	0:616601bde9fb	253	/* initialize DNS client */
AdamGreen	0:616601bde9fb	254	udp_bind(dns_pcb, IP_ADDR_ANY, 0);
AdamGreen	0:616601bde9fb	255	udp_recv(dns_pcb, dns_recv, NULL);
AdamGreen	0:616601bde9fb	256
AdamGreen	0:616601bde9fb	257	/* initialize default DNS primary server */
AdamGreen	0:616601bde9fb	258	dns_setserver(0, &dnsserver);
AdamGreen	0:616601bde9fb	259	}
AdamGreen	0:616601bde9fb	260	}
AdamGreen	0:616601bde9fb	261	#if DNS_LOCAL_HOSTLIST
AdamGreen	0:616601bde9fb	262	dns_init_local();
AdamGreen	0:616601bde9fb	263	#endif
AdamGreen	0:616601bde9fb	264	}
AdamGreen	0:616601bde9fb	265
AdamGreen	0:616601bde9fb	266	/**
AdamGreen	0:616601bde9fb	267	* Initialize one of the DNS servers.
AdamGreen	0:616601bde9fb	268	*
AdamGreen	0:616601bde9fb	269	* @param numdns the index of the DNS server to set must be < DNS_MAX_SERVERS
AdamGreen	0:616601bde9fb	270	* @param dnsserver IP address of the DNS server to set
AdamGreen	0:616601bde9fb	271	*/
AdamGreen	0:616601bde9fb	272	void
AdamGreen	0:616601bde9fb	273	dns_setserver(u8_t numdns, ip_addr_t *dnsserver)
AdamGreen	0:616601bde9fb	274	{
AdamGreen	0:616601bde9fb	275	if ((numdns < DNS_MAX_SERVERS) && (dns_pcb != NULL) &&
AdamGreen	0:616601bde9fb	276	(dnsserver != NULL) && !ip_addr_isany(dnsserver)) {
AdamGreen	0:616601bde9fb	277	dns_servers[numdns] = (*dnsserver);
AdamGreen	0:616601bde9fb	278	}
AdamGreen	0:616601bde9fb	279	}
AdamGreen	0:616601bde9fb	280
AdamGreen	0:616601bde9fb	281	/**
AdamGreen	0:616601bde9fb	282	* Obtain one of the currently configured DNS server.
AdamGreen	0:616601bde9fb	283	*
AdamGreen	0:616601bde9fb	284	* @param numdns the index of the DNS server
AdamGreen	0:616601bde9fb	285	* @return IP address of the indexed DNS server or "ip_addr_any" if the DNS
AdamGreen	0:616601bde9fb	286	* server has not been configured.
AdamGreen	0:616601bde9fb	287	*/
AdamGreen	0:616601bde9fb	288	ip_addr_t
AdamGreen	0:616601bde9fb	289	dns_getserver(u8_t numdns)
AdamGreen	0:616601bde9fb	290	{
AdamGreen	0:616601bde9fb	291	if (numdns < DNS_MAX_SERVERS) {
AdamGreen	0:616601bde9fb	292	return dns_servers[numdns];
AdamGreen	0:616601bde9fb	293	} else {
AdamGreen	0:616601bde9fb	294	return *IP_ADDR_ANY;
AdamGreen	0:616601bde9fb	295	}
AdamGreen	0:616601bde9fb	296	}
AdamGreen	0:616601bde9fb	297
AdamGreen	0:616601bde9fb	298	/**
AdamGreen	0:616601bde9fb	299	* The DNS resolver client timer - handle retries and timeouts and should
AdamGreen	0:616601bde9fb	300	* be called every DNS_TMR_INTERVAL milliseconds (every second by default).
AdamGreen	0:616601bde9fb	301	*/
AdamGreen	0:616601bde9fb	302	void
AdamGreen	0:616601bde9fb	303	dns_tmr(void)
AdamGreen	0:616601bde9fb	304	{
AdamGreen	0:616601bde9fb	305	if (dns_pcb != NULL) {
AdamGreen	0:616601bde9fb	306	LWIP_DEBUGF(DNS_DEBUG, ("dns_tmr: dns_check_entries\n"));
AdamGreen	0:616601bde9fb	307	dns_check_entries();
AdamGreen	0:616601bde9fb	308	}
AdamGreen	0:616601bde9fb	309	}
AdamGreen	0:616601bde9fb	310
AdamGreen	0:616601bde9fb	311	#if DNS_LOCAL_HOSTLIST
AdamGreen	0:616601bde9fb	312	static void
AdamGreen	0:616601bde9fb	313	dns_init_local()
AdamGreen	0:616601bde9fb	314	{
AdamGreen	0:616601bde9fb	315	#if DNS_LOCAL_HOSTLIST_IS_DYNAMIC && defined(DNS_LOCAL_HOSTLIST_INIT)
AdamGreen	0:616601bde9fb	316	int i;
AdamGreen	0:616601bde9fb	317	struct local_hostlist_entry *entry;
AdamGreen	0:616601bde9fb	318	/* Dynamic: copy entries from DNS_LOCAL_HOSTLIST_INIT to list */
AdamGreen	0:616601bde9fb	319	struct local_hostlist_entry local_hostlist_init[] = DNS_LOCAL_HOSTLIST_INIT;
AdamGreen	0:616601bde9fb	320	size_t namelen;
AdamGreen	0:616601bde9fb	321	for (i = 0; i < sizeof(local_hostlist_init) / sizeof(struct local_hostlist_entry); i++) {
AdamGreen	0:616601bde9fb	322	struct local_hostlist_entry *init_entry = &local_hostlist_init[i];
AdamGreen	0:616601bde9fb	323	LWIP_ASSERT("invalid host name (NULL)", init_entry->name != NULL);
AdamGreen	0:616601bde9fb	324	namelen = strlen(init_entry->name);
AdamGreen	0:616601bde9fb	325	LWIP_ASSERT("namelen <= DNS_LOCAL_HOSTLIST_MAX_NAMELEN", namelen <= DNS_LOCAL_HOSTLIST_MAX_NAMELEN);
AdamGreen	0:616601bde9fb	326	entry = (struct local_hostlist_entry *)memp_malloc(MEMP_LOCALHOSTLIST);
AdamGreen	0:616601bde9fb	327	LWIP_ASSERT("mem-error in dns_init_local", entry != NULL);
AdamGreen	0:616601bde9fb	328	if (entry != NULL) {
AdamGreen	0:616601bde9fb	329	entry->name = (char*)entry + sizeof(struct local_hostlist_entry);
AdamGreen	0:616601bde9fb	330	MEMCPY((char*)entry->name, init_entry->name, namelen);
AdamGreen	0:616601bde9fb	331	((char*)entry->name)[namelen] = 0;
AdamGreen	0:616601bde9fb	332	entry->addr = init_entry->addr;
AdamGreen	0:616601bde9fb	333	entry->next = local_hostlist_dynamic;
AdamGreen	0:616601bde9fb	334	local_hostlist_dynamic = entry;
AdamGreen	0:616601bde9fb	335	}
AdamGreen	0:616601bde9fb	336	}
AdamGreen	0:616601bde9fb	337	#endif /* DNS_LOCAL_HOSTLIST_IS_DYNAMIC && defined(DNS_LOCAL_HOSTLIST_INIT) */
AdamGreen	0:616601bde9fb	338	}
AdamGreen	0:616601bde9fb	339
AdamGreen	0:616601bde9fb	340	/**
AdamGreen	0:616601bde9fb	341	* Scans the local host-list for a hostname.
AdamGreen	0:616601bde9fb	342	*
AdamGreen	0:616601bde9fb	343	* @param hostname Hostname to look for in the local host-list
AdamGreen	0:616601bde9fb	344	* @return The first IP address for the hostname in the local host-list or
AdamGreen	0:616601bde9fb	345	* IPADDR_NONE if not found.
AdamGreen	0:616601bde9fb	346	*/
AdamGreen	0:616601bde9fb	347	static u32_t
AdamGreen	0:616601bde9fb	348	dns_lookup_local(const char *hostname)
AdamGreen	0:616601bde9fb	349	{
AdamGreen	0:616601bde9fb	350	#if DNS_LOCAL_HOSTLIST_IS_DYNAMIC
AdamGreen	0:616601bde9fb	351	struct local_hostlist_entry *entry = local_hostlist_dynamic;
AdamGreen	0:616601bde9fb	352	while(entry != NULL) {
AdamGreen	0:616601bde9fb	353	if(strcmp(entry->name, hostname) == 0) {
AdamGreen	0:616601bde9fb	354	return ip4_addr_get_u32(&entry->addr);
AdamGreen	0:616601bde9fb	355	}
AdamGreen	0:616601bde9fb	356	entry = entry->next;
AdamGreen	0:616601bde9fb	357	}
AdamGreen	0:616601bde9fb	358	#else /* DNS_LOCAL_HOSTLIST_IS_DYNAMIC */
AdamGreen	0:616601bde9fb	359	int i;
AdamGreen	0:616601bde9fb	360	for (i = 0; i < sizeof(local_hostlist_static) / sizeof(struct local_hostlist_entry); i++) {
AdamGreen	0:616601bde9fb	361	if(strcmp(local_hostlist_static[i].name, hostname) == 0) {
AdamGreen	0:616601bde9fb	362	return ip4_addr_get_u32(&local_hostlist_static[i].addr);
AdamGreen	0:616601bde9fb	363	}
AdamGreen	0:616601bde9fb	364	}
AdamGreen	0:616601bde9fb	365	#endif /* DNS_LOCAL_HOSTLIST_IS_DYNAMIC */
AdamGreen	0:616601bde9fb	366	return IPADDR_NONE;
AdamGreen	0:616601bde9fb	367	}
AdamGreen	0:616601bde9fb	368
AdamGreen	0:616601bde9fb	369	#if DNS_LOCAL_HOSTLIST_IS_DYNAMIC
AdamGreen	0:616601bde9fb	370	/** Remove all entries from the local host-list for a specific hostname
AdamGreen	0:616601bde9fb	371	* and/or IP addess
AdamGreen	0:616601bde9fb	372	*
AdamGreen	0:616601bde9fb	373	* @param hostname hostname for which entries shall be removed from the local
AdamGreen	0:616601bde9fb	374	* host-list
AdamGreen	0:616601bde9fb	375	* @param addr address for which entries shall be removed from the local host-list
AdamGreen	0:616601bde9fb	376	* @return the number of removed entries
AdamGreen	0:616601bde9fb	377	*/
AdamGreen	0:616601bde9fb	378	int
AdamGreen	0:616601bde9fb	379	dns_local_removehost(const char hostname, const ip_addr_t addr)
AdamGreen	0:616601bde9fb	380	{
AdamGreen	0:616601bde9fb	381	int removed = 0;
AdamGreen	0:616601bde9fb	382	struct local_hostlist_entry *entry = local_hostlist_dynamic;
AdamGreen	0:616601bde9fb	383	struct local_hostlist_entry *last_entry = NULL;
AdamGreen	0:616601bde9fb	384	while (entry != NULL) {
AdamGreen	0:616601bde9fb	385	if (((hostname == NULL) \|\| !strcmp(entry->name, hostname)) &&
AdamGreen	0:616601bde9fb	386	((addr == NULL) \|\| ip_addr_cmp(&entry->addr, addr))) {
AdamGreen	0:616601bde9fb	387	struct local_hostlist_entry *free_entry;
AdamGreen	0:616601bde9fb	388	if (last_entry != NULL) {
AdamGreen	0:616601bde9fb	389	last_entry->next = entry->next;
AdamGreen	0:616601bde9fb	390	} else {
AdamGreen	0:616601bde9fb	391	local_hostlist_dynamic = entry->next;
AdamGreen	0:616601bde9fb	392	}
AdamGreen	0:616601bde9fb	393	free_entry = entry;
AdamGreen	0:616601bde9fb	394	entry = entry->next;
AdamGreen	0:616601bde9fb	395	memp_free(MEMP_LOCALHOSTLIST, free_entry);
AdamGreen	0:616601bde9fb	396	removed++;
AdamGreen	0:616601bde9fb	397	} else {
AdamGreen	0:616601bde9fb	398	last_entry = entry;
AdamGreen	0:616601bde9fb	399	entry = entry->next;
AdamGreen	0:616601bde9fb	400	}
AdamGreen	0:616601bde9fb	401	}
AdamGreen	0:616601bde9fb	402	return removed;
AdamGreen	0:616601bde9fb	403	}
AdamGreen	0:616601bde9fb	404
AdamGreen	0:616601bde9fb	405	/**
AdamGreen	0:616601bde9fb	406	* Add a hostname/IP address pair to the local host-list.
AdamGreen	0:616601bde9fb	407	* Duplicates are not checked.
AdamGreen	0:616601bde9fb	408	*
AdamGreen	0:616601bde9fb	409	* @param hostname hostname of the new entry
AdamGreen	0:616601bde9fb	410	* @param addr IP address of the new entry
AdamGreen	0:616601bde9fb	411	* @return ERR_OK if succeeded or ERR_MEM on memory error
AdamGreen	0:616601bde9fb	412	*/
AdamGreen	0:616601bde9fb	413	err_t
AdamGreen	0:616601bde9fb	414	dns_local_addhost(const char hostname, const ip_addr_t addr)
AdamGreen	0:616601bde9fb	415	{
AdamGreen	0:616601bde9fb	416	struct local_hostlist_entry *entry;
AdamGreen	0:616601bde9fb	417	size_t namelen;
AdamGreen	0:616601bde9fb	418	LWIP_ASSERT("invalid host name (NULL)", hostname != NULL);
AdamGreen	0:616601bde9fb	419	namelen = strlen(hostname);
AdamGreen	0:616601bde9fb	420	LWIP_ASSERT("namelen <= DNS_LOCAL_HOSTLIST_MAX_NAMELEN", namelen <= DNS_LOCAL_HOSTLIST_MAX_NAMELEN);
AdamGreen	0:616601bde9fb	421	entry = (struct local_hostlist_entry *)memp_malloc(MEMP_LOCALHOSTLIST);
AdamGreen	0:616601bde9fb	422	if (entry == NULL) {
AdamGreen	0:616601bde9fb	423	return ERR_MEM;
AdamGreen	0:616601bde9fb	424	}
AdamGreen	0:616601bde9fb	425	entry->name = (char*)entry + sizeof(struct local_hostlist_entry);
AdamGreen	0:616601bde9fb	426	MEMCPY((char*)entry->name, hostname, namelen);
AdamGreen	0:616601bde9fb	427	((char*)entry->name)[namelen] = 0;
AdamGreen	0:616601bde9fb	428	ip_addr_copy(entry->addr, *addr);
AdamGreen	0:616601bde9fb	429	entry->next = local_hostlist_dynamic;
AdamGreen	0:616601bde9fb	430	local_hostlist_dynamic = entry;
AdamGreen	0:616601bde9fb	431	return ERR_OK;
AdamGreen	0:616601bde9fb	432	}
AdamGreen	0:616601bde9fb	433	#endif /* DNS_LOCAL_HOSTLIST_IS_DYNAMIC*/
AdamGreen	0:616601bde9fb	434	#endif /* DNS_LOCAL_HOSTLIST */
AdamGreen	0:616601bde9fb	435
AdamGreen	0:616601bde9fb	436	/**
AdamGreen	0:616601bde9fb	437	* Look up a hostname in the array of known hostnames.
AdamGreen	0:616601bde9fb	438	*
AdamGreen	0:616601bde9fb	439	* @note This function only looks in the internal array of known
AdamGreen	0:616601bde9fb	440	* hostnames, it does not send out a query for the hostname if none
AdamGreen	0:616601bde9fb	441	* was found. The function dns_enqueue() can be used to send a query
AdamGreen	0:616601bde9fb	442	* for a hostname.
AdamGreen	0:616601bde9fb	443	*
AdamGreen	0:616601bde9fb	444	* @param name the hostname to look up
AdamGreen	0:616601bde9fb	445	* @return the hostname's IP address, as u32_t (instead of ip_addr_t to
AdamGreen	0:616601bde9fb	446	* better check for failure: != IPADDR_NONE) or IPADDR_NONE if the hostname
AdamGreen	0:616601bde9fb	447	* was not found in the cached dns_table.
AdamGreen	0:616601bde9fb	448	*/
AdamGreen	0:616601bde9fb	449	static u32_t
AdamGreen	0:616601bde9fb	450	dns_lookup(const char *name)
AdamGreen	0:616601bde9fb	451	{
AdamGreen	0:616601bde9fb	452	u8_t i;
AdamGreen	0:616601bde9fb	453	#if DNS_LOCAL_HOSTLIST \|\| defined(DNS_LOOKUP_LOCAL_EXTERN)
AdamGreen	0:616601bde9fb	454	u32_t addr;
AdamGreen	0:616601bde9fb	455	#endif /* DNS_LOCAL_HOSTLIST \|\| defined(DNS_LOOKUP_LOCAL_EXTERN) */
AdamGreen	0:616601bde9fb	456	#if DNS_LOCAL_HOSTLIST
AdamGreen	0:616601bde9fb	457	if ((addr = dns_lookup_local(name)) != IPADDR_NONE) {
AdamGreen	0:616601bde9fb	458	return addr;
AdamGreen	0:616601bde9fb	459	}
AdamGreen	0:616601bde9fb	460	#endif /* DNS_LOCAL_HOSTLIST */
AdamGreen	0:616601bde9fb	461	#ifdef DNS_LOOKUP_LOCAL_EXTERN
AdamGreen	0:616601bde9fb	462	if((addr = DNS_LOOKUP_LOCAL_EXTERN(name)) != IPADDR_NONE) {
AdamGreen	0:616601bde9fb	463	return addr;
AdamGreen	0:616601bde9fb	464	}
AdamGreen	0:616601bde9fb	465	#endif /* DNS_LOOKUP_LOCAL_EXTERN */
AdamGreen	0:616601bde9fb	466
AdamGreen	0:616601bde9fb	467	/* Walk through name list, return entry if found. If not, return NULL. */
AdamGreen	0:616601bde9fb	468	for (i = 0; i < DNS_TABLE_SIZE; ++i) {
AdamGreen	0:616601bde9fb	469	if ((dns_table[i].state == DNS_STATE_DONE) &&
AdamGreen	0:616601bde9fb	470	(strcmp(name, dns_table[i].name) == 0)) {
AdamGreen	0:616601bde9fb	471	LWIP_DEBUGF(DNS_DEBUG, ("dns_lookup: \"%s\": found = ", name));
AdamGreen	0:616601bde9fb	472	ip_addr_debug_print(DNS_DEBUG, &(dns_table[i].ipaddr));
AdamGreen	0:616601bde9fb	473	LWIP_DEBUGF(DNS_DEBUG, ("\n"));
AdamGreen	0:616601bde9fb	474	return ip4_addr_get_u32(&dns_table[i].ipaddr);
AdamGreen	0:616601bde9fb	475	}
AdamGreen	0:616601bde9fb	476	}
AdamGreen	0:616601bde9fb	477
AdamGreen	0:616601bde9fb	478	return IPADDR_NONE;
AdamGreen	0:616601bde9fb	479	}
AdamGreen	0:616601bde9fb	480
AdamGreen	0:616601bde9fb	481	#if DNS_DOES_NAME_CHECK
AdamGreen	0:616601bde9fb	482	/**
AdamGreen	0:616601bde9fb	483	* Compare the "dotted" name "query" with the encoded name "response"
AdamGreen	0:616601bde9fb	484	* to make sure an answer from the DNS server matches the current dns_table
AdamGreen	0:616601bde9fb	485	* entry (otherwise, answers might arrive late for hostname not on the list
AdamGreen	0:616601bde9fb	486	* any more).
AdamGreen	0:616601bde9fb	487	*
AdamGreen	0:616601bde9fb	488	* @param query hostname (not encoded) from the dns_table
AdamGreen	0:616601bde9fb	489	* @param response encoded hostname in the DNS response
AdamGreen	0:616601bde9fb	490	* @return 0: names equal; 1: names differ
AdamGreen	0:616601bde9fb	491	*/
AdamGreen	0:616601bde9fb	492	static u8_t
AdamGreen	0:616601bde9fb	493	dns_compare_name(unsigned char query, unsigned char response)
AdamGreen	0:616601bde9fb	494	{
AdamGreen	0:616601bde9fb	495	unsigned char n;
AdamGreen	0:616601bde9fb	496
AdamGreen	0:616601bde9fb	497	do {
AdamGreen	0:616601bde9fb	498	n = *response++;
AdamGreen	0:616601bde9fb	499	/** @see RFC 1035 - 4.1.4. Message compression */
AdamGreen	0:616601bde9fb	500	if ((n & 0xc0) == 0xc0) {
AdamGreen	0:616601bde9fb	501	/* Compressed name */
AdamGreen	0:616601bde9fb	502	break;
AdamGreen	0:616601bde9fb	503	} else {
AdamGreen	0:616601bde9fb	504	/* Not compressed name */
AdamGreen	0:616601bde9fb	505	while (n > 0) {
AdamGreen	0:616601bde9fb	506	if ((query) != (response)) {
AdamGreen	0:616601bde9fb	507	return 1;
AdamGreen	0:616601bde9fb	508	}
AdamGreen	0:616601bde9fb	509	++response;
AdamGreen	0:616601bde9fb	510	++query;
AdamGreen	0:616601bde9fb	511	--n;
AdamGreen	0:616601bde9fb	512	};
AdamGreen	0:616601bde9fb	513	++query;
AdamGreen	0:616601bde9fb	514	}
AdamGreen	0:616601bde9fb	515	} while (*response != 0);
AdamGreen	0:616601bde9fb	516
AdamGreen	0:616601bde9fb	517	return 0;
AdamGreen	0:616601bde9fb	518	}
AdamGreen	0:616601bde9fb	519	#endif /* DNS_DOES_NAME_CHECK */
AdamGreen	0:616601bde9fb	520
AdamGreen	0:616601bde9fb	521	/**
AdamGreen	0:616601bde9fb	522	* Walk through a compact encoded DNS name and return the end of the name.
AdamGreen	0:616601bde9fb	523	*
AdamGreen	0:616601bde9fb	524	* @param query encoded DNS name in the DNS server response
AdamGreen	0:616601bde9fb	525	* @return end of the name
AdamGreen	0:616601bde9fb	526	*/
AdamGreen	0:616601bde9fb	527	static unsigned char *
AdamGreen	0:616601bde9fb	528	dns_parse_name(unsigned char *query)
AdamGreen	0:616601bde9fb	529	{
AdamGreen	0:616601bde9fb	530	unsigned char n;
AdamGreen	0:616601bde9fb	531
AdamGreen	0:616601bde9fb	532	do {
AdamGreen	0:616601bde9fb	533	n = *query++;
AdamGreen	0:616601bde9fb	534	/** @see RFC 1035 - 4.1.4. Message compression */
AdamGreen	0:616601bde9fb	535	if ((n & 0xc0) == 0xc0) {
AdamGreen	0:616601bde9fb	536	/* Compressed name */
AdamGreen	0:616601bde9fb	537	break;
AdamGreen	0:616601bde9fb	538	} else {
AdamGreen	0:616601bde9fb	539	/* Not compressed name */
AdamGreen	0:616601bde9fb	540	while (n > 0) {
AdamGreen	0:616601bde9fb	541	++query;
AdamGreen	0:616601bde9fb	542	--n;
AdamGreen	0:616601bde9fb	543	};
AdamGreen	0:616601bde9fb	544	}
AdamGreen	0:616601bde9fb	545	} while (*query != 0);
AdamGreen	0:616601bde9fb	546
AdamGreen	0:616601bde9fb	547	return query + 1;
AdamGreen	0:616601bde9fb	548	}
AdamGreen	0:616601bde9fb	549
AdamGreen	0:616601bde9fb	550	/**
AdamGreen	0:616601bde9fb	551	* Send a DNS query packet.
AdamGreen	0:616601bde9fb	552	*
AdamGreen	0:616601bde9fb	553	* @param numdns index of the DNS server in the dns_servers table
AdamGreen	0:616601bde9fb	554	* @param name hostname to query
AdamGreen	0:616601bde9fb	555	* @param id index of the hostname in dns_table, used as transaction ID in the
AdamGreen	0:616601bde9fb	556	* DNS query packet
AdamGreen	0:616601bde9fb	557	* @return ERR_OK if packet is sent; an err_t indicating the problem otherwise
AdamGreen	0:616601bde9fb	558	*/
AdamGreen	0:616601bde9fb	559	static err_t
AdamGreen	0:616601bde9fb	560	dns_send(u8_t numdns, const char* name, u8_t id)
AdamGreen	0:616601bde9fb	561	{
AdamGreen	0:616601bde9fb	562	err_t err;
AdamGreen	0:616601bde9fb	563	struct dns_hdr *hdr;
AdamGreen	0:616601bde9fb	564	struct dns_query qry;
AdamGreen	0:616601bde9fb	565	struct pbuf *p;
AdamGreen	0:616601bde9fb	566	char query, nptr;
AdamGreen	0:616601bde9fb	567	const char *pHostname;
AdamGreen	0:616601bde9fb	568	u8_t n;
AdamGreen	0:616601bde9fb	569
AdamGreen	0:616601bde9fb	570	LWIP_DEBUGF(DNS_DEBUG, ("dns_send: dns_servers[%"U16_F"] \"%s\": request\n",
AdamGreen	0:616601bde9fb	571	(u16_t)(numdns), name));
AdamGreen	0:616601bde9fb	572	LWIP_ASSERT("dns server out of array", numdns < DNS_MAX_SERVERS);
AdamGreen	0:616601bde9fb	573	LWIP_ASSERT("dns server has no IP address set", !ip_addr_isany(&dns_servers[numdns]));
AdamGreen	0:616601bde9fb	574
AdamGreen	0:616601bde9fb	575	/* if here, we have either a new query or a retry on a previous query to process */
AdamGreen	0:616601bde9fb	576	p = pbuf_alloc(PBUF_TRANSPORT, SIZEOF_DNS_HDR + DNS_MAX_NAME_LENGTH +
AdamGreen	0:616601bde9fb	577	SIZEOF_DNS_QUERY, PBUF_RAM);
AdamGreen	0:616601bde9fb	578	if (p != NULL) {
AdamGreen	0:616601bde9fb	579	LWIP_ASSERT("pbuf must be in one piece", p->next == NULL);
AdamGreen	0:616601bde9fb	580	/* fill dns header */
AdamGreen	0:616601bde9fb	581	hdr = (struct dns_hdr*)p->payload;
AdamGreen	0:616601bde9fb	582	memset(hdr, 0, SIZEOF_DNS_HDR);
AdamGreen	0:616601bde9fb	583	hdr->id = htons(id);
AdamGreen	0:616601bde9fb	584	hdr->flags1 = DNS_FLAG1_RD;
AdamGreen	0:616601bde9fb	585	hdr->numquestions = PP_HTONS(1);
AdamGreen	0:616601bde9fb	586	query = (char*)hdr + SIZEOF_DNS_HDR;
AdamGreen	0:616601bde9fb	587	pHostname = name;
AdamGreen	0:616601bde9fb	588	--pHostname;
AdamGreen	0:616601bde9fb	589
AdamGreen	0:616601bde9fb	590	/* convert hostname into suitable query format. */
AdamGreen	0:616601bde9fb	591	do {
AdamGreen	0:616601bde9fb	592	++pHostname;
AdamGreen	0:616601bde9fb	593	nptr = query;
AdamGreen	0:616601bde9fb	594	++query;
AdamGreen	0:616601bde9fb	595	for(n = 0; pHostname != '.' && pHostname != 0; ++pHostname) {
AdamGreen	0:616601bde9fb	596	query = pHostname;
AdamGreen	0:616601bde9fb	597	++query;
AdamGreen	0:616601bde9fb	598	++n;
AdamGreen	0:616601bde9fb	599	}
AdamGreen	0:616601bde9fb	600	*nptr = n;
AdamGreen	0:616601bde9fb	601	} while(*pHostname != 0);
AdamGreen	0:616601bde9fb	602	*query++='\0';
AdamGreen	0:616601bde9fb	603
AdamGreen	0:616601bde9fb	604	/* fill dns query */
AdamGreen	0:616601bde9fb	605	qry.type = PP_HTONS(DNS_RRTYPE_A);
AdamGreen	0:616601bde9fb	606	qry.cls = PP_HTONS(DNS_RRCLASS_IN);
AdamGreen	0:616601bde9fb	607	SMEMCPY(query, &qry, SIZEOF_DNS_QUERY);
AdamGreen	0:616601bde9fb	608
AdamGreen	0:616601bde9fb	609	/* resize pbuf to the exact dns query */
AdamGreen	0:616601bde9fb	610	pbuf_realloc(p, (u16_t)((query + SIZEOF_DNS_QUERY) - ((char*)(p->payload))));
AdamGreen	0:616601bde9fb	611
AdamGreen	0:616601bde9fb	612	/* connect to the server for faster receiving */
AdamGreen	0:616601bde9fb	613	udp_connect(dns_pcb, &dns_servers[numdns], DNS_SERVER_PORT);
AdamGreen	0:616601bde9fb	614	/* send dns packet */
AdamGreen	0:616601bde9fb	615	err = udp_sendto(dns_pcb, p, &dns_servers[numdns], DNS_SERVER_PORT);
AdamGreen	0:616601bde9fb	616
AdamGreen	0:616601bde9fb	617	/* free pbuf */
AdamGreen	0:616601bde9fb	618	pbuf_free(p);
AdamGreen	0:616601bde9fb	619	} else {
AdamGreen	0:616601bde9fb	620	err = ERR_MEM;
AdamGreen	0:616601bde9fb	621	}
AdamGreen	0:616601bde9fb	622
AdamGreen	0:616601bde9fb	623	return err;
AdamGreen	0:616601bde9fb	624	}
AdamGreen	0:616601bde9fb	625
AdamGreen	0:616601bde9fb	626	/**
AdamGreen	0:616601bde9fb	627	* dns_check_entry() - see if pEntry has not yet been queried and, if so, sends out a query.
AdamGreen	0:616601bde9fb	628	* Check an entry in the dns_table:
AdamGreen	0:616601bde9fb	629	* - send out query for new entries
AdamGreen	0:616601bde9fb	630	* - retry old pending entries on timeout (also with different servers)
AdamGreen	0:616601bde9fb	631	* - remove completed entries from the table if their TTL has expired
AdamGreen	0:616601bde9fb	632	*
AdamGreen	0:616601bde9fb	633	* @param i index of the dns_table entry to check
AdamGreen	0:616601bde9fb	634	*/
AdamGreen	0:616601bde9fb	635	static void
AdamGreen	0:616601bde9fb	636	dns_check_entry(u8_t i)
AdamGreen	0:616601bde9fb	637	{
AdamGreen	0:616601bde9fb	638	err_t err;
AdamGreen	0:616601bde9fb	639	struct dns_table_entry *pEntry = &dns_table[i];
AdamGreen	0:616601bde9fb	640
AdamGreen	0:616601bde9fb	641	LWIP_ASSERT("array index out of bounds", i < DNS_TABLE_SIZE);
AdamGreen	0:616601bde9fb	642
AdamGreen	0:616601bde9fb	643	switch(pEntry->state) {
AdamGreen	0:616601bde9fb	644
AdamGreen	0:616601bde9fb	645	case DNS_STATE_NEW: {
AdamGreen	0:616601bde9fb	646	/* initialize new entry */
AdamGreen	0:616601bde9fb	647	pEntry->state = DNS_STATE_ASKING;
AdamGreen	0:616601bde9fb	648	pEntry->numdns = 0;
AdamGreen	0:616601bde9fb	649	pEntry->tmr = 1;
AdamGreen	0:616601bde9fb	650	pEntry->retries = 0;
AdamGreen	0:616601bde9fb	651
AdamGreen	0:616601bde9fb	652	/* send DNS packet for this entry */
AdamGreen	0:616601bde9fb	653	err = dns_send(pEntry->numdns, pEntry->name, i);
AdamGreen	0:616601bde9fb	654	if (err != ERR_OK) {
AdamGreen	0:616601bde9fb	655	LWIP_DEBUGF(DNS_DEBUG \| LWIP_DBG_LEVEL_WARNING,
AdamGreen	0:616601bde9fb	656	("dns_send returned error: %d\n", err)); //FIX DG, lwip_strerr is part of lwip/api
AdamGreen	0:616601bde9fb	657	}
AdamGreen	0:616601bde9fb	658	break;
AdamGreen	0:616601bde9fb	659	}
AdamGreen	0:616601bde9fb	660
AdamGreen	0:616601bde9fb	661	case DNS_STATE_ASKING: {
AdamGreen	0:616601bde9fb	662	if (--pEntry->tmr == 0) {
AdamGreen	0:616601bde9fb	663	if (++pEntry->retries == DNS_MAX_RETRIES) {
AdamGreen	0:616601bde9fb	664	if ((pEntry->numdns+1<DNS_MAX_SERVERS) && !ip_addr_isany(&dns_servers[pEntry->numdns+1])) {
AdamGreen	0:616601bde9fb	665	/* change of server */
AdamGreen	0:616601bde9fb	666	pEntry->numdns++;
AdamGreen	0:616601bde9fb	667	pEntry->tmr = 1;
AdamGreen	0:616601bde9fb	668	pEntry->retries = 0;
AdamGreen	0:616601bde9fb	669	break;
AdamGreen	0:616601bde9fb	670	} else {
AdamGreen	0:616601bde9fb	671	LWIP_DEBUGF(DNS_DEBUG, ("dns_check_entry: \"%s\": timeout\n", pEntry->name));
AdamGreen	0:616601bde9fb	672	/* call specified callback function if provided */
AdamGreen	0:616601bde9fb	673	if (pEntry->found)
AdamGreen	0:616601bde9fb	674	(*pEntry->found)(pEntry->name, NULL, pEntry->arg);
AdamGreen	0:616601bde9fb	675	/* flush this entry */
AdamGreen	0:616601bde9fb	676	pEntry->state = DNS_STATE_UNUSED;
AdamGreen	0:616601bde9fb	677	pEntry->found = NULL;
AdamGreen	0:616601bde9fb	678	break;
AdamGreen	0:616601bde9fb	679	}
AdamGreen	0:616601bde9fb	680	}
AdamGreen	0:616601bde9fb	681
AdamGreen	0:616601bde9fb	682	/* wait longer for the next retry */
AdamGreen	0:616601bde9fb	683	pEntry->tmr = pEntry->retries;
AdamGreen	0:616601bde9fb	684
AdamGreen	0:616601bde9fb	685	/* send DNS packet for this entry */
AdamGreen	0:616601bde9fb	686	err = dns_send(pEntry->numdns, pEntry->name, i);
AdamGreen	0:616601bde9fb	687	if (err != ERR_OK) {
AdamGreen	0:616601bde9fb	688	LWIP_DEBUGF(DNS_DEBUG \| LWIP_DBG_LEVEL_WARNING,
AdamGreen	0:616601bde9fb	689	("dns_send returned error: %d\n", err)); //FIX DG, lwip_strerr is part of lwip/api
AdamGreen	0:616601bde9fb	690	}
AdamGreen	0:616601bde9fb	691	}
AdamGreen	0:616601bde9fb	692	break;
AdamGreen	0:616601bde9fb	693	}
AdamGreen	0:616601bde9fb	694
AdamGreen	0:616601bde9fb	695	case DNS_STATE_DONE: {
AdamGreen	0:616601bde9fb	696	/* if the time to live is nul */
AdamGreen	0:616601bde9fb	697	if (--pEntry->ttl == 0) {
AdamGreen	0:616601bde9fb	698	LWIP_DEBUGF(DNS_DEBUG, ("dns_check_entry: \"%s\": flush\n", pEntry->name));
AdamGreen	0:616601bde9fb	699	/* flush this entry */
AdamGreen	0:616601bde9fb	700	pEntry->state = DNS_STATE_UNUSED;
AdamGreen	0:616601bde9fb	701	pEntry->found = NULL;
AdamGreen	0:616601bde9fb	702	}
AdamGreen	0:616601bde9fb	703	break;
AdamGreen	0:616601bde9fb	704	}
AdamGreen	0:616601bde9fb	705	case DNS_STATE_UNUSED:
AdamGreen	0:616601bde9fb	706	/* nothing to do */
AdamGreen	0:616601bde9fb	707	break;
AdamGreen	0:616601bde9fb	708	default:
AdamGreen	0:616601bde9fb	709	LWIP_ASSERT("unknown dns_table entry state:", 0);
AdamGreen	0:616601bde9fb	710	break;
AdamGreen	0:616601bde9fb	711	}
AdamGreen	0:616601bde9fb	712	}
AdamGreen	0:616601bde9fb	713
AdamGreen	0:616601bde9fb	714	/**
AdamGreen	0:616601bde9fb	715	* Call dns_check_entry for each entry in dns_table - check all entries.
AdamGreen	0:616601bde9fb	716	*/
AdamGreen	0:616601bde9fb	717	static void
AdamGreen	0:616601bde9fb	718	dns_check_entries(void)
AdamGreen	0:616601bde9fb	719	{
AdamGreen	0:616601bde9fb	720	u8_t i;
AdamGreen	0:616601bde9fb	721
AdamGreen	0:616601bde9fb	722	for (i = 0; i < DNS_TABLE_SIZE; ++i) {
AdamGreen	0:616601bde9fb	723	dns_check_entry(i);
AdamGreen	0:616601bde9fb	724	}
AdamGreen	0:616601bde9fb	725	}
AdamGreen	0:616601bde9fb	726
AdamGreen	0:616601bde9fb	727	/**
AdamGreen	0:616601bde9fb	728	* Receive input function for DNS response packets arriving for the dns UDP pcb.
AdamGreen	0:616601bde9fb	729	*
AdamGreen	0:616601bde9fb	730	* @params see udp.h
AdamGreen	0:616601bde9fb	731	*/
AdamGreen	0:616601bde9fb	732	static void
AdamGreen	0:616601bde9fb	733	dns_recv(void arg, struct udp_pcb pcb, struct pbuf p, ip_addr_t addr, u16_t port)
AdamGreen	0:616601bde9fb	734	{
AdamGreen	0:616601bde9fb	735	u16_t i;
AdamGreen	0:616601bde9fb	736	char *pHostname;
AdamGreen	0:616601bde9fb	737	struct dns_hdr *hdr;
AdamGreen	0:616601bde9fb	738	struct dns_answer ans;
AdamGreen	0:616601bde9fb	739	struct dns_table_entry *pEntry;
AdamGreen	0:616601bde9fb	740	u16_t nquestions, nanswers;
AdamGreen	0:616601bde9fb	741
AdamGreen	0:616601bde9fb	742	LWIP_UNUSED_ARG(arg);
AdamGreen	0:616601bde9fb	743	LWIP_UNUSED_ARG(pcb);
AdamGreen	0:616601bde9fb	744	LWIP_UNUSED_ARG(addr);
AdamGreen	0:616601bde9fb	745	LWIP_UNUSED_ARG(port);
AdamGreen	0:616601bde9fb	746
AdamGreen	0:616601bde9fb	747	/* is the dns message too big ? */
AdamGreen	0:616601bde9fb	748	if (p->tot_len > DNS_MSG_SIZE) {
AdamGreen	0:616601bde9fb	749	LWIP_DEBUGF(DNS_DEBUG, ("dns_recv: pbuf too big\n"));
AdamGreen	0:616601bde9fb	750	/* free pbuf and return */
AdamGreen	0:616601bde9fb	751	goto memerr;
AdamGreen	0:616601bde9fb	752	}
AdamGreen	0:616601bde9fb	753
AdamGreen	0:616601bde9fb	754	/* is the dns message big enough ? */
AdamGreen	0:616601bde9fb	755	if (p->tot_len < (SIZEOF_DNS_HDR + SIZEOF_DNS_QUERY + SIZEOF_DNS_ANSWER)) {
AdamGreen	0:616601bde9fb	756	LWIP_DEBUGF(DNS_DEBUG, ("dns_recv: pbuf too small\n"));
AdamGreen	0:616601bde9fb	757	/* free pbuf and return */
AdamGreen	0:616601bde9fb	758	goto memerr;
AdamGreen	0:616601bde9fb	759	}
AdamGreen	0:616601bde9fb	760
AdamGreen	0:616601bde9fb	761	/* copy dns payload inside static buffer for processing */
AdamGreen	0:616601bde9fb	762	if (pbuf_copy_partial(p, dns_payload, p->tot_len, 0) == p->tot_len) {
AdamGreen	0:616601bde9fb	763	/* The ID in the DNS header should be our entry into the name table. */
AdamGreen	0:616601bde9fb	764	hdr = (struct dns_hdr*)dns_payload;
AdamGreen	0:616601bde9fb	765	i = htons(hdr->id);
AdamGreen	0:616601bde9fb	766	if (i < DNS_TABLE_SIZE) {
AdamGreen	0:616601bde9fb	767	pEntry = &dns_table[i];
AdamGreen	0:616601bde9fb	768	if(pEntry->state == DNS_STATE_ASKING) {
AdamGreen	0:616601bde9fb	769	/* This entry is now completed. */
AdamGreen	0:616601bde9fb	770	pEntry->state = DNS_STATE_DONE;
AdamGreen	0:616601bde9fb	771	pEntry->err = hdr->flags2 & DNS_FLAG2_ERR_MASK;
AdamGreen	0:616601bde9fb	772
AdamGreen	0:616601bde9fb	773	/* We only care about the question(s) and the answers. The authrr
AdamGreen	0:616601bde9fb	774	and the extrarr are simply discarded. */
AdamGreen	0:616601bde9fb	775	nquestions = htons(hdr->numquestions);
AdamGreen	0:616601bde9fb	776	nanswers = htons(hdr->numanswers);
AdamGreen	0:616601bde9fb	777
AdamGreen	0:616601bde9fb	778	/* Check for error. If so, call callback to inform. */
AdamGreen	0:616601bde9fb	779	if (((hdr->flags1 & DNS_FLAG1_RESPONSE) == 0) \|\| (pEntry->err != 0) \|\| (nquestions != 1)) {
AdamGreen	0:616601bde9fb	780	LWIP_DEBUGF(DNS_DEBUG, ("dns_recv: \"%s\": error in flags\n", pEntry->name));
AdamGreen	0:616601bde9fb	781	/* call callback to indicate error, clean up memory and return */
AdamGreen	0:616601bde9fb	782	goto responseerr;
AdamGreen	0:616601bde9fb	783	}
AdamGreen	0:616601bde9fb	784
AdamGreen	0:616601bde9fb	785	#if DNS_DOES_NAME_CHECK
AdamGreen	0:616601bde9fb	786	/* Check if the name in the "question" part match with the name in the entry. */
AdamGreen	0:616601bde9fb	787	if (dns_compare_name((unsigned char )(pEntry->name), (unsigned char )dns_payload + SIZEOF_DNS_HDR) != 0) {
AdamGreen	0:616601bde9fb	788	LWIP_DEBUGF(DNS_DEBUG, ("dns_recv: \"%s\": response not match to query\n", pEntry->name));
AdamGreen	0:616601bde9fb	789	/* call callback to indicate error, clean up memory and return */
AdamGreen	0:616601bde9fb	790	goto responseerr;
AdamGreen	0:616601bde9fb	791	}
AdamGreen	0:616601bde9fb	792	#endif /* DNS_DOES_NAME_CHECK */
AdamGreen	0:616601bde9fb	793
AdamGreen	0:616601bde9fb	794	/* Skip the name in the "question" part */
AdamGreen	0:616601bde9fb	795	pHostname = (char ) dns_parse_name((unsigned char )dns_payload + SIZEOF_DNS_HDR) + SIZEOF_DNS_QUERY;
AdamGreen	0:616601bde9fb	796
AdamGreen	0:616601bde9fb	797	while (nanswers > 0) {
AdamGreen	0:616601bde9fb	798	/* skip answer resource record's host name */
AdamGreen	0:616601bde9fb	799	pHostname = (char ) dns_parse_name((unsigned char )pHostname);
AdamGreen	0:616601bde9fb	800
AdamGreen	0:616601bde9fb	801	/* Check for IP address type and Internet class. Others are discarded. */
AdamGreen	0:616601bde9fb	802	SMEMCPY(&ans, pHostname, SIZEOF_DNS_ANSWER);
AdamGreen	0:616601bde9fb	803	if((ans.type == PP_HTONS(DNS_RRTYPE_A)) && (ans.cls == PP_HTONS(DNS_RRCLASS_IN)) &&
AdamGreen	0:616601bde9fb	804	(ans.len == PP_HTONS(sizeof(ip_addr_t))) ) {
AdamGreen	0:616601bde9fb	805	/* read the answer resource record's TTL, and maximize it if needed */
AdamGreen	0:616601bde9fb	806	pEntry->ttl = ntohl(ans.ttl);
AdamGreen	0:616601bde9fb	807	if (pEntry->ttl > DNS_MAX_TTL) {
AdamGreen	0:616601bde9fb	808	pEntry->ttl = DNS_MAX_TTL;
AdamGreen	0:616601bde9fb	809	}
AdamGreen	0:616601bde9fb	810	/* read the IP address after answer resource record's header */
AdamGreen	0:616601bde9fb	811	SMEMCPY(&(pEntry->ipaddr), (pHostname+SIZEOF_DNS_ANSWER), sizeof(ip_addr_t));
AdamGreen	0:616601bde9fb	812	LWIP_DEBUGF(DNS_DEBUG, ("dns_recv: \"%s\": response = ", pEntry->name));
AdamGreen	0:616601bde9fb	813	ip_addr_debug_print(DNS_DEBUG, (&(pEntry->ipaddr)));
AdamGreen	0:616601bde9fb	814	LWIP_DEBUGF(DNS_DEBUG, ("\n"));
AdamGreen	0:616601bde9fb	815	/* call specified callback function if provided */
AdamGreen	0:616601bde9fb	816	if (pEntry->found) {
AdamGreen	0:616601bde9fb	817	(*pEntry->found)(pEntry->name, &pEntry->ipaddr, pEntry->arg);
AdamGreen	0:616601bde9fb	818	}
AdamGreen	0:616601bde9fb	819	/* deallocate memory and return */
AdamGreen	0:616601bde9fb	820	goto memerr;
AdamGreen	0:616601bde9fb	821	} else {
AdamGreen	0:616601bde9fb	822	pHostname = pHostname + SIZEOF_DNS_ANSWER + htons(ans.len);
AdamGreen	0:616601bde9fb	823	}
AdamGreen	0:616601bde9fb	824	--nanswers;
AdamGreen	0:616601bde9fb	825	}
AdamGreen	0:616601bde9fb	826	LWIP_DEBUGF(DNS_DEBUG, ("dns_recv: \"%s\": error in response\n", pEntry->name));
AdamGreen	0:616601bde9fb	827	/* call callback to indicate error, clean up memory and return */
AdamGreen	0:616601bde9fb	828	goto responseerr;
AdamGreen	0:616601bde9fb	829	}
AdamGreen	0:616601bde9fb	830	}
AdamGreen	0:616601bde9fb	831	}
AdamGreen	0:616601bde9fb	832
AdamGreen	0:616601bde9fb	833	/* deallocate memory and return */
AdamGreen	0:616601bde9fb	834	goto memerr;
AdamGreen	0:616601bde9fb	835
AdamGreen	0:616601bde9fb	836	responseerr:
AdamGreen	0:616601bde9fb	837	/* ERROR: call specified callback function with NULL as name to indicate an error */
AdamGreen	0:616601bde9fb	838	if (pEntry->found) {
AdamGreen	0:616601bde9fb	839	(*pEntry->found)(pEntry->name, NULL, pEntry->arg);
AdamGreen	0:616601bde9fb	840	}
AdamGreen	0:616601bde9fb	841	/* flush this entry */
AdamGreen	0:616601bde9fb	842	pEntry->state = DNS_STATE_UNUSED;
AdamGreen	0:616601bde9fb	843	pEntry->found = NULL;
AdamGreen	0:616601bde9fb	844
AdamGreen	0:616601bde9fb	845	memerr:
AdamGreen	0:616601bde9fb	846	/* free pbuf */
AdamGreen	0:616601bde9fb	847	pbuf_free(p);
AdamGreen	0:616601bde9fb	848	return;
AdamGreen	0:616601bde9fb	849	}
AdamGreen	0:616601bde9fb	850
AdamGreen	0:616601bde9fb	851	/**
AdamGreen	0:616601bde9fb	852	* Queues a new hostname to resolve and sends out a DNS query for that hostname
AdamGreen	0:616601bde9fb	853	*
AdamGreen	0:616601bde9fb	854	* @param name the hostname that is to be queried
AdamGreen	0:616601bde9fb	855	* @param found a callback founction to be called on success, failure or timeout
AdamGreen	0:616601bde9fb	856	* @param callback_arg argument to pass to the callback function
AdamGreen	0:616601bde9fb	857	* @return @return a err_t return code.
AdamGreen	0:616601bde9fb	858	*/
AdamGreen	0:616601bde9fb	859	static err_t
AdamGreen	0:616601bde9fb	860	dns_enqueue(const char name, dns_found_callback found, void callback_arg)
AdamGreen	0:616601bde9fb	861	{
AdamGreen	0:616601bde9fb	862	u8_t i;
AdamGreen	0:616601bde9fb	863	u8_t lseq, lseqi;
AdamGreen	0:616601bde9fb	864	struct dns_table_entry *pEntry = NULL;
AdamGreen	0:616601bde9fb	865	size_t namelen;
AdamGreen	0:616601bde9fb	866
AdamGreen	0:616601bde9fb	867	/* search an unused entry, or the oldest one */
AdamGreen	0:616601bde9fb	868	lseq = lseqi = 0;
AdamGreen	0:616601bde9fb	869	for (i = 0; i < DNS_TABLE_SIZE; ++i) {
AdamGreen	0:616601bde9fb	870	pEntry = &dns_table[i];
AdamGreen	0:616601bde9fb	871	/* is it an unused entry ? */
AdamGreen	0:616601bde9fb	872	if (pEntry->state == DNS_STATE_UNUSED)
AdamGreen	0:616601bde9fb	873	break;
AdamGreen	0:616601bde9fb	874
AdamGreen	0:616601bde9fb	875	/* check if this is the oldest completed entry */
AdamGreen	0:616601bde9fb	876	if (pEntry->state == DNS_STATE_DONE) {
AdamGreen	0:616601bde9fb	877	if ((dns_seqno - pEntry->seqno) > lseq) {
AdamGreen	0:616601bde9fb	878	lseq = dns_seqno - pEntry->seqno;
AdamGreen	0:616601bde9fb	879	lseqi = i;
AdamGreen	0:616601bde9fb	880	}
AdamGreen	0:616601bde9fb	881	}
AdamGreen	0:616601bde9fb	882	}
AdamGreen	0:616601bde9fb	883
AdamGreen	0:616601bde9fb	884	/* if we don't have found an unused entry, use the oldest completed one */
AdamGreen	0:616601bde9fb	885	if (i == DNS_TABLE_SIZE) {
AdamGreen	0:616601bde9fb	886	if ((lseqi >= DNS_TABLE_SIZE) \|\| (dns_table[lseqi].state != DNS_STATE_DONE)) {
AdamGreen	0:616601bde9fb	887	/* no entry can't be used now, table is full */
AdamGreen	0:616601bde9fb	888	LWIP_DEBUGF(DNS_DEBUG, ("dns_enqueue: \"%s\": DNS entries table is full\n", name));
AdamGreen	0:616601bde9fb	889	return ERR_MEM;
AdamGreen	0:616601bde9fb	890	} else {
AdamGreen	0:616601bde9fb	891	/* use the oldest completed one */
AdamGreen	0:616601bde9fb	892	i = lseqi;
AdamGreen	0:616601bde9fb	893	pEntry = &dns_table[i];
AdamGreen	0:616601bde9fb	894	}
AdamGreen	0:616601bde9fb	895	}
AdamGreen	0:616601bde9fb	896
AdamGreen	0:616601bde9fb	897	/* use this entry */
AdamGreen	0:616601bde9fb	898	LWIP_DEBUGF(DNS_DEBUG, ("dns_enqueue: \"%s\": use DNS entry %"U16_F"\n", name, (u16_t)(i)));
AdamGreen	0:616601bde9fb	899
AdamGreen	0:616601bde9fb	900	/* fill the entry */
AdamGreen	0:616601bde9fb	901	pEntry->state = DNS_STATE_NEW;
AdamGreen	0:616601bde9fb	902	pEntry->seqno = dns_seqno++;
AdamGreen	0:616601bde9fb	903	pEntry->found = found;
AdamGreen	0:616601bde9fb	904	pEntry->arg = callback_arg;
AdamGreen	0:616601bde9fb	905	namelen = LWIP_MIN(strlen(name), DNS_MAX_NAME_LENGTH-1);
AdamGreen	0:616601bde9fb	906	MEMCPY(pEntry->name, name, namelen);
AdamGreen	0:616601bde9fb	907	pEntry->name[namelen] = 0;
AdamGreen	0:616601bde9fb	908
AdamGreen	0:616601bde9fb	909	/* force to send query without waiting timer */
AdamGreen	0:616601bde9fb	910	dns_check_entry(i);
AdamGreen	0:616601bde9fb	911
AdamGreen	0:616601bde9fb	912	/* dns query is enqueued */
AdamGreen	0:616601bde9fb	913	return ERR_INPROGRESS;
AdamGreen	0:616601bde9fb	914	}
AdamGreen	0:616601bde9fb	915
AdamGreen	0:616601bde9fb	916	/**
AdamGreen	0:616601bde9fb	917	* Resolve a hostname (string) into an IP address.
AdamGreen	0:616601bde9fb	918	* NON-BLOCKING callback version for use with raw API!!!
AdamGreen	0:616601bde9fb	919	*
AdamGreen	0:616601bde9fb	920	* Returns immediately with one of err_t return codes:
AdamGreen	0:616601bde9fb	921	* - ERR_OK if hostname is a valid IP address string or the host
AdamGreen	0:616601bde9fb	922	* name is already in the local names table.
AdamGreen	0:616601bde9fb	923	* - ERR_INPROGRESS enqueue a request to be sent to the DNS server
AdamGreen	0:616601bde9fb	924	* for resolution if no errors are present.
AdamGreen	0:616601bde9fb	925	*
AdamGreen	0:616601bde9fb	926	* @param hostname the hostname that is to be queried
AdamGreen	0:616601bde9fb	927	* @param addr pointer to a ip_addr_t where to store the address if it is already
AdamGreen	0:616601bde9fb	928	* cached in the dns_table (only valid if ERR_OK is returned!)
AdamGreen	0:616601bde9fb	929	* @param found a callback function to be called on success, failure or timeout (only if
AdamGreen	0:616601bde9fb	930	* ERR_INPROGRESS is returned!)
AdamGreen	0:616601bde9fb	931	* @param callback_arg argument to pass to the callback function
AdamGreen	0:616601bde9fb	932	* @return a err_t return code.
AdamGreen	0:616601bde9fb	933	*/
AdamGreen	0:616601bde9fb	934	err_t
AdamGreen	0:616601bde9fb	935	dns_gethostbyname(const char hostname, ip_addr_t addr, dns_found_callback found,
AdamGreen	0:616601bde9fb	936	void *callback_arg)
AdamGreen	0:616601bde9fb	937	{
AdamGreen	0:616601bde9fb	938	u32_t ipaddr;
AdamGreen	0:616601bde9fb	939	/* not initialized or no valid server yet, or invalid addr pointer
AdamGreen	0:616601bde9fb	940	* or invalid hostname or invalid hostname length */
AdamGreen	0:616601bde9fb	941	if ((dns_pcb == NULL) \|\| (addr == NULL) \|\|
AdamGreen	0:616601bde9fb	942	(!hostname) \|\| (!hostname[0]) \|\|
AdamGreen	0:616601bde9fb	943	(strlen(hostname) >= DNS_MAX_NAME_LENGTH)) {
AdamGreen	0:616601bde9fb	944	return ERR_VAL;
AdamGreen	0:616601bde9fb	945	}
AdamGreen	0:616601bde9fb	946
AdamGreen	0:616601bde9fb	947	#if LWIP_HAVE_LOOPIF
AdamGreen	0:616601bde9fb	948	if (strcmp(hostname, "localhost")==0) {
AdamGreen	0:616601bde9fb	949	ip_addr_set_loopback(addr);
AdamGreen	0:616601bde9fb	950	return ERR_OK;
AdamGreen	0:616601bde9fb	951	}
AdamGreen	0:616601bde9fb	952	#endif /* LWIP_HAVE_LOOPIF */
AdamGreen	0:616601bde9fb	953
AdamGreen	0:616601bde9fb	954	/* host name already in octet notation? set ip addr and return ERR_OK */
AdamGreen	0:616601bde9fb	955	ipaddr = ipaddr_addr(hostname);
AdamGreen	0:616601bde9fb	956	if (ipaddr == IPADDR_NONE) {
AdamGreen	0:616601bde9fb	957	/* already have this address cached? */
AdamGreen	0:616601bde9fb	958	ipaddr = dns_lookup(hostname);
AdamGreen	0:616601bde9fb	959	}
AdamGreen	0:616601bde9fb	960	if (ipaddr != IPADDR_NONE) {
AdamGreen	0:616601bde9fb	961	ip4_addr_set_u32(addr, ipaddr);
AdamGreen	0:616601bde9fb	962	return ERR_OK;
AdamGreen	0:616601bde9fb	963	}
AdamGreen	0:616601bde9fb	964
AdamGreen	0:616601bde9fb	965	/* queue query with specified callback */
AdamGreen	0:616601bde9fb	966	return dns_enqueue(hostname, found, callback_arg);
AdamGreen	0:616601bde9fb	967	}
AdamGreen	0:616601bde9fb	968
AdamGreen	0:616601bde9fb	969	#endif /* LWIP_DNS */

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Type:	Program
Mbed OS support:	Mbed 2 deprecated
Created:	23 Feb 2012
Imports:	113
Forks:	0
Commits:	2
Dependents:	0
Dependencies:	4
Followers:	6

NetStack/lwip/core/dns.c@0:616601bde9fb, 2012-02-23 (annotated)

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