Bonjour - First step: AutoIP compiled in and working

Users » darran » Code » Bonjour

Darran Shepherd / Mbed 2 deprecated Bonjour

First step: AutoIP compiled in and working

lwip/core/dns.c@0:55a05330f8cc, 2010-06-18 (annotated)

Committer:: darran
Date:: Fri Jun 18 09:11:35 2010 +0000
Revision:: 0:55a05330f8cc
Child:: 1:4218cacaf696

Who changed what in which revision?

User	Revision	Line number	New contents of line
darran	0:55a05330f8cc	1	/**
darran	0:55a05330f8cc	2	* @file
darran	0:55a05330f8cc	3	* DNS - host name to IP address resolver.
darran	0:55a05330f8cc	4	*
darran	0:55a05330f8cc	5	*/
darran	0:55a05330f8cc	6
darran	0:55a05330f8cc	7	/**
darran	0:55a05330f8cc	8
darran	0:55a05330f8cc	9	* This file implements a DNS host name to IP address resolver.
darran	0:55a05330f8cc	10
darran	0:55a05330f8cc	11	* Port to lwIP from uIP
darran	0:55a05330f8cc	12	* by Jim Pettinato April 2007
darran	0:55a05330f8cc	13
darran	0:55a05330f8cc	14	* uIP version Copyright (c) 2002-2003, Adam Dunkels.
darran	0:55a05330f8cc	15	* All rights reserved.
darran	0:55a05330f8cc	16	*
darran	0:55a05330f8cc	17	* Redistribution and use in source and binary forms, with or without
darran	0:55a05330f8cc	18	* modification, are permitted provided that the following conditions
darran	0:55a05330f8cc	19	* are met:
darran	0:55a05330f8cc	20	* 1. Redistributions of source code must retain the above copyright
darran	0:55a05330f8cc	21	* notice, this list of conditions and the following disclaimer.
darran	0:55a05330f8cc	22	* 2. Redistributions in binary form must reproduce the above copyright
darran	0:55a05330f8cc	23	* notice, this list of conditions and the following disclaimer in the
darran	0:55a05330f8cc	24	* documentation and/or other materials provided with the distribution.
darran	0:55a05330f8cc	25	* 3. The name of the author may not be used to endorse or promote
darran	0:55a05330f8cc	26	* products derived from this software without specific prior
darran	0:55a05330f8cc	27	* written permission.
darran	0:55a05330f8cc	28	*
darran	0:55a05330f8cc	29	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
darran	0:55a05330f8cc	30	* OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
darran	0:55a05330f8cc	31	* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
darran	0:55a05330f8cc	32	* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
darran	0:55a05330f8cc	33	* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
darran	0:55a05330f8cc	34	* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
darran	0:55a05330f8cc	35	* GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
darran	0:55a05330f8cc	36	* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
darran	0:55a05330f8cc	37	* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
darran	0:55a05330f8cc	38	* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
darran	0:55a05330f8cc	39	* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
darran	0:55a05330f8cc	40	*
darran	0:55a05330f8cc	41	*
darran	0:55a05330f8cc	42	* DNS.C
darran	0:55a05330f8cc	43	*
darran	0:55a05330f8cc	44	* The lwIP DNS resolver functions are used to lookup a host name and
darran	0:55a05330f8cc	45	* map it to a numerical IP address. It maintains a list of resolved
darran	0:55a05330f8cc	46	* hostnames that can be queried with the dns_lookup() function.
darran	0:55a05330f8cc	47	* New hostnames can be resolved using the dns_query() function.
darran	0:55a05330f8cc	48	*
darran	0:55a05330f8cc	49	* The lwIP version of the resolver also adds a non-blocking version of
darran	0:55a05330f8cc	50	* gethostbyname() that will work with a raw API application. This function
darran	0:55a05330f8cc	51	* checks for an IP address string first and converts it if it is valid.
darran	0:55a05330f8cc	52	* gethostbyname() then does a dns_lookup() to see if the name is
darran	0:55a05330f8cc	53	* already in the table. If so, the IP is returned. If not, a query is
darran	0:55a05330f8cc	54	* issued and the function returns with a ERR_INPROGRESS status. The app
darran	0:55a05330f8cc	55	* using the dns client must then go into a waiting state.
darran	0:55a05330f8cc	56	*
darran	0:55a05330f8cc	57	* Once a hostname has been resolved (or found to be non-existent),
darran	0:55a05330f8cc	58	* the resolver code calls a specified callback function (which
darran	0:55a05330f8cc	59	* must be implemented by the module that uses the resolver).
darran	0:55a05330f8cc	60	*/
darran	0:55a05330f8cc	61
darran	0:55a05330f8cc	62	/*-----------------------------------------------------------------------------
darran	0:55a05330f8cc	63	* RFC 1035 - Domain names - implementation and specification
darran	0:55a05330f8cc	64	* RFC 2181 - Clarifications to the DNS Specification
darran	0:55a05330f8cc	65	----------------------------------------------------------------------------/
darran	0:55a05330f8cc	66
darran	0:55a05330f8cc	67	/** @todo: define good default values (rfc compliance) */
darran	0:55a05330f8cc	68	/** @todo: improve answer parsing, more checkings... */
darran	0:55a05330f8cc	69	/** @todo: check RFC1035 - 7.3. Processing responses */
darran	0:55a05330f8cc	70
darran	0:55a05330f8cc	71	/*-----------------------------------------------------------------------------
darran	0:55a05330f8cc	72	* Includes
darran	0:55a05330f8cc	73	----------------------------------------------------------------------------/
darran	0:55a05330f8cc	74
darran	0:55a05330f8cc	75	#include "lwip/opt.h"
darran	0:55a05330f8cc	76
darran	0:55a05330f8cc	77	#if LWIP_DNS /* don't build if not configured for use in lwipopts.h */
darran	0:55a05330f8cc	78
darran	0:55a05330f8cc	79	#include "lwip/udp.h"
darran	0:55a05330f8cc	80	#include "lwip/mem.h"
darran	0:55a05330f8cc	81	#include "lwip/dns.h"
darran	0:55a05330f8cc	82
darran	0:55a05330f8cc	83	#include <string.h>
darran	0:55a05330f8cc	84
darran	0:55a05330f8cc	85	/** DNS server IP address */
darran	0:55a05330f8cc	86	#ifndef DNS_SERVER_ADDRESS
darran	0:55a05330f8cc	87	#define DNS_SERVER_ADDRESS(ipaddr) (ip4_addr_set_u32(ipaddr, ipaddr_addr("208.67.222.222"))) /* resolver1.opendns.com */
darran	0:55a05330f8cc	88	#endif
darran	0:55a05330f8cc	89
darran	0:55a05330f8cc	90	/** DNS server port address */
darran	0:55a05330f8cc	91	#ifndef DNS_SERVER_PORT
darran	0:55a05330f8cc	92	#define DNS_SERVER_PORT 53
darran	0:55a05330f8cc	93	#endif
darran	0:55a05330f8cc	94
darran	0:55a05330f8cc	95	/** DNS maximum number of retries when asking for a name, before "timeout". */
darran	0:55a05330f8cc	96	#ifndef DNS_MAX_RETRIES
darran	0:55a05330f8cc	97	#define DNS_MAX_RETRIES 4
darran	0:55a05330f8cc	98	#endif
darran	0:55a05330f8cc	99
darran	0:55a05330f8cc	100	/** DNS resource record max. TTL (one week as default) */
darran	0:55a05330f8cc	101	#ifndef DNS_MAX_TTL
darran	0:55a05330f8cc	102	#define DNS_MAX_TTL 604800
darran	0:55a05330f8cc	103	#endif
darran	0:55a05330f8cc	104
darran	0:55a05330f8cc	105	/* DNS protocol flags */
darran	0:55a05330f8cc	106	#define DNS_FLAG1_RESPONSE 0x80
darran	0:55a05330f8cc	107	#define DNS_FLAG1_OPCODE_STATUS 0x10
darran	0:55a05330f8cc	108	#define DNS_FLAG1_OPCODE_INVERSE 0x08
darran	0:55a05330f8cc	109	#define DNS_FLAG1_OPCODE_STANDARD 0x00
darran	0:55a05330f8cc	110	#define DNS_FLAG1_AUTHORATIVE 0x04
darran	0:55a05330f8cc	111	#define DNS_FLAG1_TRUNC 0x02
darran	0:55a05330f8cc	112	#define DNS_FLAG1_RD 0x01
darran	0:55a05330f8cc	113	#define DNS_FLAG2_RA 0x80
darran	0:55a05330f8cc	114	#define DNS_FLAG2_ERR_MASK 0x0f
darran	0:55a05330f8cc	115	#define DNS_FLAG2_ERR_NONE 0x00
darran	0:55a05330f8cc	116	#define DNS_FLAG2_ERR_NAME 0x03
darran	0:55a05330f8cc	117
darran	0:55a05330f8cc	118	/* DNS protocol states */
darran	0:55a05330f8cc	119	#define DNS_STATE_UNUSED 0
darran	0:55a05330f8cc	120	#define DNS_STATE_NEW 1
darran	0:55a05330f8cc	121	#define DNS_STATE_ASKING 2
darran	0:55a05330f8cc	122	#define DNS_STATE_DONE 3
darran	0:55a05330f8cc	123
darran	0:55a05330f8cc	124	#ifdef PACK_STRUCT_USE_INCLUDES
darran	0:55a05330f8cc	125	# include "arch/bpstruct.h"
darran	0:55a05330f8cc	126	#endif
darran	0:55a05330f8cc	127	PACK_STRUCT_BEGIN
darran	0:55a05330f8cc	128	/** DNS message header */
darran	0:55a05330f8cc	129	struct dns_hdr {
darran	0:55a05330f8cc	130	PACK_STRUCT_FIELD(u16_t id);
darran	0:55a05330f8cc	131	PACK_STRUCT_FIELD(u8_t flags1);
darran	0:55a05330f8cc	132	PACK_STRUCT_FIELD(u8_t flags2);
darran	0:55a05330f8cc	133	PACK_STRUCT_FIELD(u16_t numquestions);
darran	0:55a05330f8cc	134	PACK_STRUCT_FIELD(u16_t numanswers);
darran	0:55a05330f8cc	135	PACK_STRUCT_FIELD(u16_t numauthrr);
darran	0:55a05330f8cc	136	PACK_STRUCT_FIELD(u16_t numextrarr);
darran	0:55a05330f8cc	137	} PACK_STRUCT_STRUCT;
darran	0:55a05330f8cc	138	PACK_STRUCT_END
darran	0:55a05330f8cc	139	#ifdef PACK_STRUCT_USE_INCLUDES
darran	0:55a05330f8cc	140	# include "arch/epstruct.h"
darran	0:55a05330f8cc	141	#endif
darran	0:55a05330f8cc	142	#define SIZEOF_DNS_HDR 12
darran	0:55a05330f8cc	143
darran	0:55a05330f8cc	144	/** DNS query message structure.
darran	0:55a05330f8cc	145	No packing needed: only used locally on the stack. */
darran	0:55a05330f8cc	146	PACK_STRUCT_BEGIN
darran	0:55a05330f8cc	147	struct dns_query {
darran	0:55a05330f8cc	148	/* DNS query record starts with either a domain name or a pointer
darran	0:55a05330f8cc	149	to a name already present somewhere in the packet. */
darran	0:55a05330f8cc	150	u16_t type;
darran	0:55a05330f8cc	151	u16_t cls;
darran	0:55a05330f8cc	152	} PACK_STRUCT_STRUCT;
darran	0:55a05330f8cc	153	PACK_STRUCT_END
darran	0:55a05330f8cc	154	#define SIZEOF_DNS_QUERY 4
darran	0:55a05330f8cc	155
darran	0:55a05330f8cc	156	/** DNS answer message structure.
darran	0:55a05330f8cc	157	No packing needed: only used locally on the stack. */
darran	0:55a05330f8cc	158	PACK_STRUCT_BEGIN
darran	0:55a05330f8cc	159	struct dns_answer {
darran	0:55a05330f8cc	160	/* DNS answer record starts with either a domain name or a pointer
darran	0:55a05330f8cc	161	to a name already present somewhere in the packet. */
darran	0:55a05330f8cc	162	u16_t type;
darran	0:55a05330f8cc	163	u16_t cls;
darran	0:55a05330f8cc	164	u32_t ttl;
darran	0:55a05330f8cc	165	u16_t len;
darran	0:55a05330f8cc	166	} PACK_STRUCT_STRUCT;
darran	0:55a05330f8cc	167	PACK_STRUCT_END
darran	0:55a05330f8cc	168	#define SIZEOF_DNS_ANSWER 10
darran	0:55a05330f8cc	169
darran	0:55a05330f8cc	170	/** DNS table entry */
darran	0:55a05330f8cc	171	struct dns_table_entry {
darran	0:55a05330f8cc	172	u8_t state;
darran	0:55a05330f8cc	173	u8_t numdns;
darran	0:55a05330f8cc	174	u8_t tmr;
darran	0:55a05330f8cc	175	u8_t retries;
darran	0:55a05330f8cc	176	u8_t seqno;
darran	0:55a05330f8cc	177	u8_t err;
darran	0:55a05330f8cc	178	u32_t ttl;
darran	0:55a05330f8cc	179	char name[DNS_MAX_NAME_LENGTH];
darran	0:55a05330f8cc	180	ip_addr_t ipaddr;
darran	0:55a05330f8cc	181	/* pointer to callback on DNS query done */
darran	0:55a05330f8cc	182	dns_found_callback found;
darran	0:55a05330f8cc	183	void *arg;
darran	0:55a05330f8cc	184	};
darran	0:55a05330f8cc	185
darran	0:55a05330f8cc	186	#if DNS_LOCAL_HOSTLIST
darran	0:55a05330f8cc	187	/** struct used for local host-list */
darran	0:55a05330f8cc	188	struct local_hostlist_entry {
darran	0:55a05330f8cc	189	/** static hostname */
darran	0:55a05330f8cc	190	const char *name;
darran	0:55a05330f8cc	191	/** static host address in network byteorder */
darran	0:55a05330f8cc	192	ip_addr_t addr;
darran	0:55a05330f8cc	193	struct local_hostlist_entry *next;
darran	0:55a05330f8cc	194	};
darran	0:55a05330f8cc	195
darran	0:55a05330f8cc	196	#if DNS_LOCAL_HOSTLIST_IS_DYNAMIC
darran	0:55a05330f8cc	197	/** Local host-list. For hostnames in this list, no
darran	0:55a05330f8cc	198	* external name resolution is performed */
darran	0:55a05330f8cc	199	static struct local_hostlist_entry *local_hostlist_dynamic;
darran	0:55a05330f8cc	200	#else /* DNS_LOCAL_HOSTLIST_IS_DYNAMIC */
darran	0:55a05330f8cc	201
darran	0:55a05330f8cc	202	/** Defining this allows the local_hostlist_static to be placed in a different
darran	0:55a05330f8cc	203	* linker section (e.g. FLASH) */
darran	0:55a05330f8cc	204	#ifndef DNS_LOCAL_HOSTLIST_STORAGE_PRE
darran	0:55a05330f8cc	205	#define DNS_LOCAL_HOSTLIST_STORAGE_PRE static
darran	0:55a05330f8cc	206	#endif /* DNS_LOCAL_HOSTLIST_STORAGE_PRE */
darran	0:55a05330f8cc	207	/** Defining this allows the local_hostlist_static to be placed in a different
darran	0:55a05330f8cc	208	* linker section (e.g. FLASH) */
darran	0:55a05330f8cc	209	#ifndef DNS_LOCAL_HOSTLIST_STORAGE_POST
darran	0:55a05330f8cc	210	#define DNS_LOCAL_HOSTLIST_STORAGE_POST
darran	0:55a05330f8cc	211	#endif /* DNS_LOCAL_HOSTLIST_STORAGE_POST */
darran	0:55a05330f8cc	212	DNS_LOCAL_HOSTLIST_STORAGE_PRE struct local_hostlist_entry local_hostlist_static[]
darran	0:55a05330f8cc	213	DNS_LOCAL_HOSTLIST_STORAGE_POST = DNS_LOCAL_HOSTLIST_INIT;
darran	0:55a05330f8cc	214
darran	0:55a05330f8cc	215	#endif /* DNS_LOCAL_HOSTLIST_IS_DYNAMIC */
darran	0:55a05330f8cc	216
darran	0:55a05330f8cc	217	static void dns_init_local();
darran	0:55a05330f8cc	218	#endif /* DNS_LOCAL_HOSTLIST */
darran	0:55a05330f8cc	219
darran	0:55a05330f8cc	220
darran	0:55a05330f8cc	221	/* forward declarations */
darran	0:55a05330f8cc	222	static void dns_recv(void s, struct udp_pcb pcb, struct pbuf p, ip_addr_t addr, u16_t port);
darran	0:55a05330f8cc	223	static void dns_check_entries(void);
darran	0:55a05330f8cc	224
darran	0:55a05330f8cc	225	/*-----------------------------------------------------------------------------
darran	0:55a05330f8cc	226	* Globales
darran	0:55a05330f8cc	227	----------------------------------------------------------------------------/
darran	0:55a05330f8cc	228
darran	0:55a05330f8cc	229	/* DNS variables */
darran	0:55a05330f8cc	230	static struct udp_pcb *dns_pcb;
darran	0:55a05330f8cc	231	static u8_t dns_seqno;
darran	0:55a05330f8cc	232	static struct dns_table_entry dns_table[DNS_TABLE_SIZE];
darran	0:55a05330f8cc	233	static ip_addr_t dns_servers[DNS_MAX_SERVERS];
darran	0:55a05330f8cc	234	/** Contiguous buffer for processing responses */
darran	0:55a05330f8cc	235	static u8_t dns_payload_buffer[LWIP_MEM_ALIGN_BUFFER(DNS_MSG_SIZE)];
darran	0:55a05330f8cc	236	static u8_t* dns_payload;
darran	0:55a05330f8cc	237
darran	0:55a05330f8cc	238	/**
darran	0:55a05330f8cc	239	* Initialize the resolver: set up the UDP pcb and configure the default server
darran	0:55a05330f8cc	240	* (DNS_SERVER_ADDRESS).
darran	0:55a05330f8cc	241	*/
darran	0:55a05330f8cc	242	void
darran	0:55a05330f8cc	243	dns_init()
darran	0:55a05330f8cc	244	{
darran	0:55a05330f8cc	245	ip_addr_t dnsserver;
darran	0:55a05330f8cc	246
darran	0:55a05330f8cc	247	dns_payload = (u8_t *)LWIP_MEM_ALIGN(dns_payload_buffer);
darran	0:55a05330f8cc	248
darran	0:55a05330f8cc	249	/* initialize default DNS server address */
darran	0:55a05330f8cc	250	DNS_SERVER_ADDRESS(&dnsserver);
darran	0:55a05330f8cc	251
darran	0:55a05330f8cc	252	LWIP_DEBUGF(DNS_DEBUG, ("dns_init: initializing\n"));
darran	0:55a05330f8cc	253
darran	0:55a05330f8cc	254	/* if dns client not yet initialized... */
darran	0:55a05330f8cc	255	if (dns_pcb == NULL) {
darran	0:55a05330f8cc	256	dns_pcb = udp_new();
darran	0:55a05330f8cc	257
darran	0:55a05330f8cc	258	if (dns_pcb != NULL) {
darran	0:55a05330f8cc	259	/* initialize DNS table not needed (initialized to zero since it is a
darran	0:55a05330f8cc	260	* global variable) */
darran	0:55a05330f8cc	261	LWIP_ASSERT("For implicit initialization to work, DNS_STATE_UNUSED needs to be 0",
darran	0:55a05330f8cc	262	DNS_STATE_UNUSED == 0);
darran	0:55a05330f8cc	263
darran	0:55a05330f8cc	264	/* initialize DNS client */
darran	0:55a05330f8cc	265	udp_bind(dns_pcb, IP_ADDR_ANY, 0);
darran	0:55a05330f8cc	266	udp_recv(dns_pcb, dns_recv, NULL);
darran	0:55a05330f8cc	267
darran	0:55a05330f8cc	268	/* initialize default DNS primary server */
darran	0:55a05330f8cc	269	dns_setserver(0, &dnsserver);
darran	0:55a05330f8cc	270	}
darran	0:55a05330f8cc	271	}
darran	0:55a05330f8cc	272	#if DNS_LOCAL_HOSTLIST
darran	0:55a05330f8cc	273	dns_init_local();
darran	0:55a05330f8cc	274	#endif
darran	0:55a05330f8cc	275	}
darran	0:55a05330f8cc	276
darran	0:55a05330f8cc	277	/**
darran	0:55a05330f8cc	278	* Initialize one of the DNS servers.
darran	0:55a05330f8cc	279	*
darran	0:55a05330f8cc	280	* @param numdns the index of the DNS server to set must be < DNS_MAX_SERVERS
darran	0:55a05330f8cc	281	* @param dnsserver IP address of the DNS server to set
darran	0:55a05330f8cc	282	*/
darran	0:55a05330f8cc	283	void
darran	0:55a05330f8cc	284	dns_setserver(u8_t numdns, ip_addr_t *dnsserver)
darran	0:55a05330f8cc	285	{
darran	0:55a05330f8cc	286	if ((numdns < DNS_MAX_SERVERS) && (dns_pcb != NULL) &&
darran	0:55a05330f8cc	287	(dnsserver != NULL) && !ip_addr_isany(dnsserver)) {
darran	0:55a05330f8cc	288	dns_servers[numdns] = (*dnsserver);
darran	0:55a05330f8cc	289	}
darran	0:55a05330f8cc	290	}
darran	0:55a05330f8cc	291
darran	0:55a05330f8cc	292	/**
darran	0:55a05330f8cc	293	* Obtain one of the currently configured DNS server.
darran	0:55a05330f8cc	294	*
darran	0:55a05330f8cc	295	* @param numdns the index of the DNS server
darran	0:55a05330f8cc	296	* @return IP address of the indexed DNS server or "ip_addr_any" if the DNS
darran	0:55a05330f8cc	297	* server has not been configured.
darran	0:55a05330f8cc	298	*/
darran	0:55a05330f8cc	299	ip_addr_t
darran	0:55a05330f8cc	300	dns_getserver(u8_t numdns)
darran	0:55a05330f8cc	301	{
darran	0:55a05330f8cc	302	if (numdns < DNS_MAX_SERVERS) {
darran	0:55a05330f8cc	303	return dns_servers[numdns];
darran	0:55a05330f8cc	304	} else {
darran	0:55a05330f8cc	305	return *IP_ADDR_ANY;
darran	0:55a05330f8cc	306	}
darran	0:55a05330f8cc	307	}
darran	0:55a05330f8cc	308
darran	0:55a05330f8cc	309	/**
darran	0:55a05330f8cc	310	* The DNS resolver client timer - handle retries and timeouts and should
darran	0:55a05330f8cc	311	* be called every DNS_TMR_INTERVAL milliseconds (every second by default).
darran	0:55a05330f8cc	312	*/
darran	0:55a05330f8cc	313	void
darran	0:55a05330f8cc	314	dns_tmr(void)
darran	0:55a05330f8cc	315	{
darran	0:55a05330f8cc	316	if (dns_pcb != NULL) {
darran	0:55a05330f8cc	317	LWIP_DEBUGF(DNS_DEBUG, ("dns_tmr: dns_check_entries\n"));
darran	0:55a05330f8cc	318	dns_check_entries();
darran	0:55a05330f8cc	319	}
darran	0:55a05330f8cc	320	}
darran	0:55a05330f8cc	321
darran	0:55a05330f8cc	322	#if DNS_LOCAL_HOSTLIST
darran	0:55a05330f8cc	323	static void
darran	0:55a05330f8cc	324	dns_init_local()
darran	0:55a05330f8cc	325	{
darran	0:55a05330f8cc	326	#if DNS_LOCAL_HOSTLIST_IS_DYNAMIC && defined(DNS_LOCAL_HOSTLIST_INIT)
darran	0:55a05330f8cc	327	int i;
darran	0:55a05330f8cc	328	struct local_hostlist_entry *entry;
darran	0:55a05330f8cc	329	/* Dynamic: copy entries from DNS_LOCAL_HOSTLIST_INIT to list */
darran	0:55a05330f8cc	330	struct local_hostlist_entry local_hostlist_init[] = DNS_LOCAL_HOSTLIST_INIT;
darran	0:55a05330f8cc	331	size_t namelen;
darran	0:55a05330f8cc	332	for (i = 0; i < sizeof(local_hostlist_init) / sizeof(struct local_hostlist_entry); i++) {
darran	0:55a05330f8cc	333	struct local_hostlist_entry *init_entry = &local_hostlist_init[i];
darran	0:55a05330f8cc	334	LWIP_ASSERT("invalid host name (NULL)", init_entry->name != NULL);
darran	0:55a05330f8cc	335	namelen = strlen(init_entry->name);
darran	0:55a05330f8cc	336	entry = mem_malloc((mem_size_t)(sizeof(struct local_hostlist_entry) + namelen + 1));
darran	0:55a05330f8cc	337	LWIP_ASSERT("mem-error in dns_init_local", entry != NULL);
darran	0:55a05330f8cc	338	if (entry != NULL) {
darran	0:55a05330f8cc	339	entry->name = (char*)entry + sizeof(struct local_hostlist_entry);
darran	0:55a05330f8cc	340	MEMCPY((char*)entry->name, init_entry->name, namelen);
darran	0:55a05330f8cc	341	((char*)entry->name)[namelen] = 0;
darran	0:55a05330f8cc	342	entry->addr = init_entry->addr;
darran	0:55a05330f8cc	343	entry->next = local_hostlist_dynamic;
darran	0:55a05330f8cc	344	local_hostlist_dynamic = entry;
darran	0:55a05330f8cc	345	}
darran	0:55a05330f8cc	346	}
darran	0:55a05330f8cc	347	#endif /* DNS_LOCAL_HOSTLIST_IS_DYNAMIC && defined(DNS_LOCAL_HOSTLIST_INIT) */
darran	0:55a05330f8cc	348	}
darran	0:55a05330f8cc	349
darran	0:55a05330f8cc	350	/**
darran	0:55a05330f8cc	351	* Scans the local host-list for a hostname.
darran	0:55a05330f8cc	352	*
darran	0:55a05330f8cc	353	* @param hostname Hostname to look for in the local host-list
darran	0:55a05330f8cc	354	* @return The first IP address for the hostname in the local host-list or
darran	0:55a05330f8cc	355	* IPADDR_NONE if not found.
darran	0:55a05330f8cc	356	*/
darran	0:55a05330f8cc	357	static u32_t
darran	0:55a05330f8cc	358	dns_lookup_local(const char *hostname)
darran	0:55a05330f8cc	359	{
darran	0:55a05330f8cc	360	#if DNS_LOCAL_HOSTLIST_IS_DYNAMIC
darran	0:55a05330f8cc	361	struct local_hostlist_entry *entry = local_hostlist_dynamic;
darran	0:55a05330f8cc	362	while(entry != NULL) {
darran	0:55a05330f8cc	363	if(strcmp(entry->name, hostname) == 0) {
darran	0:55a05330f8cc	364	return ip4_addr_get_u32(&entry->addr);
darran	0:55a05330f8cc	365	}
darran	0:55a05330f8cc	366	entry = entry->next;
darran	0:55a05330f8cc	367	}
darran	0:55a05330f8cc	368	#else /* DNS_LOCAL_HOSTLIST_IS_DYNAMIC */
darran	0:55a05330f8cc	369	int i;
darran	0:55a05330f8cc	370	for (i = 0; i < sizeof(local_hostlist_static) / sizeof(struct local_hostlist_entry); i++) {
darran	0:55a05330f8cc	371	if(strcmp(local_hostlist_static[i].name, hostname) == 0) {
darran	0:55a05330f8cc	372	return ip4_addr_get_u32(&local_hostlist_static[i].addr);
darran	0:55a05330f8cc	373	}
darran	0:55a05330f8cc	374	}
darran	0:55a05330f8cc	375	#endif /* DNS_LOCAL_HOSTLIST_IS_DYNAMIC */
darran	0:55a05330f8cc	376	return IPADDR_NONE;
darran	0:55a05330f8cc	377	}
darran	0:55a05330f8cc	378
darran	0:55a05330f8cc	379	#if DNS_LOCAL_HOSTLIST_IS_DYNAMIC
darran	0:55a05330f8cc	380	/** Remove all entries from the local host-list for a specific hostname
darran	0:55a05330f8cc	381	* and/or IP addess
darran	0:55a05330f8cc	382	*
darran	0:55a05330f8cc	383	* @param hostname hostname for which entries shall be removed from the local
darran	0:55a05330f8cc	384	* host-list
darran	0:55a05330f8cc	385	* @param addr address for which entries shall be removed from the local host-list
darran	0:55a05330f8cc	386	* @return the number of removed entries
darran	0:55a05330f8cc	387	*/
darran	0:55a05330f8cc	388	int
darran	0:55a05330f8cc	389	dns_local_removehost(const char hostname, const ip_addr_t addr)
darran	0:55a05330f8cc	390	{
darran	0:55a05330f8cc	391	int removed = 0;
darran	0:55a05330f8cc	392	struct local_hostlist_entry *entry = local_hostlist_dynamic;
darran	0:55a05330f8cc	393	struct local_hostlist_entry *last_entry = NULL;
darran	0:55a05330f8cc	394	while (entry != NULL) {
darran	0:55a05330f8cc	395	if (((hostname == NULL) \|\| !strcmp(entry->name, hostname)) &&
darran	0:55a05330f8cc	396	((addr == NULL) \|\| ip_addr_cmp(&entry->addr, addr))) {
darran	0:55a05330f8cc	397	struct local_hostlist_entry *free_entry;
darran	0:55a05330f8cc	398	if (last_entry != NULL) {
darran	0:55a05330f8cc	399	last_entry->next = entry->next;
darran	0:55a05330f8cc	400	} else {
darran	0:55a05330f8cc	401	local_hostlist_dynamic = entry->next;
darran	0:55a05330f8cc	402	}
darran	0:55a05330f8cc	403	free_entry = entry;
darran	0:55a05330f8cc	404	entry = entry->next;
darran	0:55a05330f8cc	405	mem_free(free_entry);
darran	0:55a05330f8cc	406	removed++;
darran	0:55a05330f8cc	407	} else {
darran	0:55a05330f8cc	408	last_entry = entry;
darran	0:55a05330f8cc	409	entry = entry->next;
darran	0:55a05330f8cc	410	}
darran	0:55a05330f8cc	411	}
darran	0:55a05330f8cc	412	return removed;
darran	0:55a05330f8cc	413	}
darran	0:55a05330f8cc	414
darran	0:55a05330f8cc	415	/**
darran	0:55a05330f8cc	416	* Add a hostname/IP address pair to the local host-list.
darran	0:55a05330f8cc	417	* Duplicates are not checked.
darran	0:55a05330f8cc	418	*
darran	0:55a05330f8cc	419	* @param hostname hostname of the new entry
darran	0:55a05330f8cc	420	* @param addr IP address of the new entry
darran	0:55a05330f8cc	421	* @return ERR_OK if succeeded or ERR_MEM on memory error
darran	0:55a05330f8cc	422	*/
darran	0:55a05330f8cc	423	err_t
darran	0:55a05330f8cc	424	dns_local_addhost(const char hostname, const ip_addr_t addr)
darran	0:55a05330f8cc	425	{
darran	0:55a05330f8cc	426	struct local_hostlist_entry *entry;
darran	0:55a05330f8cc	427	size_t namelen;
darran	0:55a05330f8cc	428	LWIP_ASSERT("invalid host name (NULL)", hostname != NULL);
darran	0:55a05330f8cc	429	namelen = strlen(hostname);
darran	0:55a05330f8cc	430	entry = mem_malloc((mem_size_t)(sizeof(struct local_hostlist_entry) + namelen + 1));
darran	0:55a05330f8cc	431	if (entry == NULL) {
darran	0:55a05330f8cc	432	return ERR_MEM;
darran	0:55a05330f8cc	433	}
darran	0:55a05330f8cc	434	entry->name = (char*)entry + sizeof(struct local_hostlist_entry);
darran	0:55a05330f8cc	435	MEMCPY((char*)entry->name, hostname, namelen);
darran	0:55a05330f8cc	436	((char*)entry->name)[namelen] = 0;
darran	0:55a05330f8cc	437	ip_addr_copy(entry->addr, *addr);
darran	0:55a05330f8cc	438	entry->next = local_hostlist_dynamic;
darran	0:55a05330f8cc	439	local_hostlist_dynamic = entry;
darran	0:55a05330f8cc	440	return ERR_OK;
darran	0:55a05330f8cc	441	}
darran	0:55a05330f8cc	442	#endif /* DNS_LOCAL_HOSTLIST_IS_DYNAMIC*/
darran	0:55a05330f8cc	443	#endif /* DNS_LOCAL_HOSTLIST */
darran	0:55a05330f8cc	444
darran	0:55a05330f8cc	445	/**
darran	0:55a05330f8cc	446	* Look up a hostname in the array of known hostnames.
darran	0:55a05330f8cc	447	*
darran	0:55a05330f8cc	448	* @note This function only looks in the internal array of known
darran	0:55a05330f8cc	449	* hostnames, it does not send out a query for the hostname if none
darran	0:55a05330f8cc	450	* was found. The function dns_enqueue() can be used to send a query
darran	0:55a05330f8cc	451	* for a hostname.
darran	0:55a05330f8cc	452	*
darran	0:55a05330f8cc	453	* @param name the hostname to look up
darran	0:55a05330f8cc	454	* @return the hostname's IP address, as u32_t (instead of ip_addr_t to
darran	0:55a05330f8cc	455	* better check for failure: != IPADDR_NONE) or IPADDR_NONE if the hostname
darran	0:55a05330f8cc	456	* was not found in the cached dns_table.
darran	0:55a05330f8cc	457	*/
darran	0:55a05330f8cc	458	static u32_t
darran	0:55a05330f8cc	459	dns_lookup(const char *name)
darran	0:55a05330f8cc	460	{
darran	0:55a05330f8cc	461	u8_t i;
darran	0:55a05330f8cc	462	#if DNS_LOCAL_HOSTLIST \|\| defined(DNS_LOOKUP_LOCAL_EXTERN)
darran	0:55a05330f8cc	463	u32_t addr;
darran	0:55a05330f8cc	464	#endif /* DNS_LOCAL_HOSTLIST \|\| defined(DNS_LOOKUP_LOCAL_EXTERN) */
darran	0:55a05330f8cc	465	#if DNS_LOCAL_HOSTLIST
darran	0:55a05330f8cc	466	if ((addr = dns_lookup_local(name)) != IPADDR_NONE) {
darran	0:55a05330f8cc	467	return addr;
darran	0:55a05330f8cc	468	}
darran	0:55a05330f8cc	469	#endif /* DNS_LOCAL_HOSTLIST */
darran	0:55a05330f8cc	470	#ifdef DNS_LOOKUP_LOCAL_EXTERN
darran	0:55a05330f8cc	471	if((addr = DNS_LOOKUP_LOCAL_EXTERN(name)) != IPADDR_NONE) {
darran	0:55a05330f8cc	472	return addr;
darran	0:55a05330f8cc	473	}
darran	0:55a05330f8cc	474	#endif /* DNS_LOOKUP_LOCAL_EXTERN */
darran	0:55a05330f8cc	475
darran	0:55a05330f8cc	476	/* Walk through name list, return entry if found. If not, return NULL. */
darran	0:55a05330f8cc	477	for (i = 0; i < DNS_TABLE_SIZE; ++i) {
darran	0:55a05330f8cc	478	if ((dns_table[i].state == DNS_STATE_DONE) &&
darran	0:55a05330f8cc	479	(strcmp(name, dns_table[i].name) == 0)) {
darran	0:55a05330f8cc	480	LWIP_DEBUGF(DNS_DEBUG, ("dns_lookup: \"%s\": found = ", name));
darran	0:55a05330f8cc	481	ip_addr_debug_print(DNS_DEBUG, &(dns_table[i].ipaddr));
darran	0:55a05330f8cc	482	LWIP_DEBUGF(DNS_DEBUG, ("\n"));
darran	0:55a05330f8cc	483	return ip4_addr_get_u32(&dns_table[i].ipaddr);
darran	0:55a05330f8cc	484	}
darran	0:55a05330f8cc	485	}
darran	0:55a05330f8cc	486
darran	0:55a05330f8cc	487	return IPADDR_NONE;
darran	0:55a05330f8cc	488	}
darran	0:55a05330f8cc	489
darran	0:55a05330f8cc	490	#if DNS_DOES_NAME_CHECK
darran	0:55a05330f8cc	491	/**
darran	0:55a05330f8cc	492	* Compare the "dotted" name "query" with the encoded name "response"
darran	0:55a05330f8cc	493	* to make sure an answer from the DNS server matches the current dns_table
darran	0:55a05330f8cc	494	* entry (otherwise, answers might arrive late for hostname not on the list
darran	0:55a05330f8cc	495	* any more).
darran	0:55a05330f8cc	496	*
darran	0:55a05330f8cc	497	* @param query hostname (not encoded) from the dns_table
darran	0:55a05330f8cc	498	* @param response encoded hostname in the DNS response
darran	0:55a05330f8cc	499	* @return 0: names equal; 1: names differ
darran	0:55a05330f8cc	500	*/
darran	0:55a05330f8cc	501	static u8_t
darran	0:55a05330f8cc	502	dns_compare_name(unsigned char query, unsigned char response)
darran	0:55a05330f8cc	503	{
darran	0:55a05330f8cc	504	unsigned char n;
darran	0:55a05330f8cc	505
darran	0:55a05330f8cc	506	do {
darran	0:55a05330f8cc	507	n = *response++;
darran	0:55a05330f8cc	508	/** @see RFC 1035 - 4.1.4. Message compression */
darran	0:55a05330f8cc	509	if ((n & 0xc0) == 0xc0) {
darran	0:55a05330f8cc	510	/* Compressed name */
darran	0:55a05330f8cc	511	break;
darran	0:55a05330f8cc	512	} else {
darran	0:55a05330f8cc	513	/* Not compressed name */
darran	0:55a05330f8cc	514	while (n > 0) {
darran	0:55a05330f8cc	515	if ((query) != (response)) {
darran	0:55a05330f8cc	516	return 1;
darran	0:55a05330f8cc	517	}
darran	0:55a05330f8cc	518	++response;
darran	0:55a05330f8cc	519	++query;
darran	0:55a05330f8cc	520	--n;
darran	0:55a05330f8cc	521	};
darran	0:55a05330f8cc	522	++query;
darran	0:55a05330f8cc	523	}
darran	0:55a05330f8cc	524	} while (*response != 0);
darran	0:55a05330f8cc	525
darran	0:55a05330f8cc	526	return 0;
darran	0:55a05330f8cc	527	}
darran	0:55a05330f8cc	528	#endif /* DNS_DOES_NAME_CHECK */
darran	0:55a05330f8cc	529
darran	0:55a05330f8cc	530	/**
darran	0:55a05330f8cc	531	* Walk through a compact encoded DNS name and return the end of the name.
darran	0:55a05330f8cc	532	*
darran	0:55a05330f8cc	533	* @param query encoded DNS name in the DNS server response
darran	0:55a05330f8cc	534	* @return end of the name
darran	0:55a05330f8cc	535	*/
darran	0:55a05330f8cc	536	static unsigned char *
darran	0:55a05330f8cc	537	dns_parse_name(unsigned char *query)
darran	0:55a05330f8cc	538	{
darran	0:55a05330f8cc	539	unsigned char n;
darran	0:55a05330f8cc	540
darran	0:55a05330f8cc	541	do {
darran	0:55a05330f8cc	542	n = *query++;
darran	0:55a05330f8cc	543	/** @see RFC 1035 - 4.1.4. Message compression */
darran	0:55a05330f8cc	544	if ((n & 0xc0) == 0xc0) {
darran	0:55a05330f8cc	545	/* Compressed name */
darran	0:55a05330f8cc	546	break;
darran	0:55a05330f8cc	547	} else {
darran	0:55a05330f8cc	548	/* Not compressed name */
darran	0:55a05330f8cc	549	while (n > 0) {
darran	0:55a05330f8cc	550	++query;
darran	0:55a05330f8cc	551	--n;
darran	0:55a05330f8cc	552	};
darran	0:55a05330f8cc	553	}
darran	0:55a05330f8cc	554	} while (*query != 0);
darran	0:55a05330f8cc	555
darran	0:55a05330f8cc	556	return query + 1;
darran	0:55a05330f8cc	557	}
darran	0:55a05330f8cc	558
darran	0:55a05330f8cc	559	/**
darran	0:55a05330f8cc	560	* Send a DNS query packet.
darran	0:55a05330f8cc	561	*
darran	0:55a05330f8cc	562	* @param numdns index of the DNS server in the dns_servers table
darran	0:55a05330f8cc	563	* @param name hostname to query
darran	0:55a05330f8cc	564	* @param id index of the hostname in dns_table, used as transaction ID in the
darran	0:55a05330f8cc	565	* DNS query packet
darran	0:55a05330f8cc	566	* @return ERR_OK if packet is sent; an err_t indicating the problem otherwise
darran	0:55a05330f8cc	567	*/
darran	0:55a05330f8cc	568	static err_t
darran	0:55a05330f8cc	569	dns_send(u8_t numdns, const char* name, u8_t id)
darran	0:55a05330f8cc	570	{
darran	0:55a05330f8cc	571	err_t err;
darran	0:55a05330f8cc	572	struct dns_hdr *hdr;
darran	0:55a05330f8cc	573	struct dns_query qry;
darran	0:55a05330f8cc	574	struct pbuf *p;
darran	0:55a05330f8cc	575	char query, nptr;
darran	0:55a05330f8cc	576	const char *pHostname;
darran	0:55a05330f8cc	577	u8_t n;
darran	0:55a05330f8cc	578
darran	0:55a05330f8cc	579	LWIP_DEBUGF(DNS_DEBUG, ("dns_send: dns_servers[%"U16_F"] \"%s\": request\n",
darran	0:55a05330f8cc	580	(u16_t)(numdns), name));
darran	0:55a05330f8cc	581	LWIP_ASSERT("dns server out of array", numdns < DNS_MAX_SERVERS);
darran	0:55a05330f8cc	582	LWIP_ASSERT("dns server has no IP address set", !ip_addr_isany(&dns_servers[numdns]));
darran	0:55a05330f8cc	583
darran	0:55a05330f8cc	584	/* if here, we have either a new query or a retry on a previous query to process */
darran	0:55a05330f8cc	585	p = pbuf_alloc(PBUF_TRANSPORT, SIZEOF_DNS_HDR + DNS_MAX_NAME_LENGTH +
darran	0:55a05330f8cc	586	SIZEOF_DNS_QUERY, PBUF_RAM);
darran	0:55a05330f8cc	587	if (p != NULL) {
darran	0:55a05330f8cc	588	LWIP_ASSERT("pbuf must be in one piece", p->next == NULL);
darran	0:55a05330f8cc	589	/* fill dns header */
darran	0:55a05330f8cc	590	hdr = (struct dns_hdr*)p->payload;
darran	0:55a05330f8cc	591	memset(hdr, 0, SIZEOF_DNS_HDR);
darran	0:55a05330f8cc	592	hdr->id = htons(id);
darran	0:55a05330f8cc	593	hdr->flags1 = DNS_FLAG1_RD;
darran	0:55a05330f8cc	594	hdr->numquestions = htons(1);
darran	0:55a05330f8cc	595	query = (char*)hdr + SIZEOF_DNS_HDR;
darran	0:55a05330f8cc	596	pHostname = name;
darran	0:55a05330f8cc	597	--pHostname;
darran	0:55a05330f8cc	598
darran	0:55a05330f8cc	599	/* convert hostname into suitable query format. */
darran	0:55a05330f8cc	600	do {
darran	0:55a05330f8cc	601	++pHostname;
darran	0:55a05330f8cc	602	nptr = query;
darran	0:55a05330f8cc	603	++query;
darran	0:55a05330f8cc	604	for(n = 0; pHostname != '.' && pHostname != 0; ++pHostname) {
darran	0:55a05330f8cc	605	query = pHostname;
darran	0:55a05330f8cc	606	++query;
darran	0:55a05330f8cc	607	++n;
darran	0:55a05330f8cc	608	}
darran	0:55a05330f8cc	609	*nptr = n;
darran	0:55a05330f8cc	610	} while(*pHostname != 0);
darran	0:55a05330f8cc	611	*query++='\0';
darran	0:55a05330f8cc	612
darran	0:55a05330f8cc	613	/* fill dns query */
darran	0:55a05330f8cc	614	qry.type = htons(DNS_RRTYPE_A);
darran	0:55a05330f8cc	615	qry.cls = htons(DNS_RRCLASS_IN);
darran	0:55a05330f8cc	616	SMEMCPY(query, &qry, SIZEOF_DNS_QUERY);
darran	0:55a05330f8cc	617
darran	0:55a05330f8cc	618	/* resize pbuf to the exact dns query */
darran	0:55a05330f8cc	619	pbuf_realloc(p, (u16_t)((query + SIZEOF_DNS_QUERY) - ((char*)(p->payload))));
darran	0:55a05330f8cc	620
darran	0:55a05330f8cc	621	/* connect to the server for faster receiving */
darran	0:55a05330f8cc	622	udp_connect(dns_pcb, &dns_servers[numdns], DNS_SERVER_PORT);
darran	0:55a05330f8cc	623	/* send dns packet */
darran	0:55a05330f8cc	624	err = udp_sendto(dns_pcb, p, &dns_servers[numdns], DNS_SERVER_PORT);
darran	0:55a05330f8cc	625
darran	0:55a05330f8cc	626	/* free pbuf */
darran	0:55a05330f8cc	627	pbuf_free(p);
darran	0:55a05330f8cc	628	} else {
darran	0:55a05330f8cc	629	err = ERR_MEM;
darran	0:55a05330f8cc	630	}
darran	0:55a05330f8cc	631
darran	0:55a05330f8cc	632	return err;
darran	0:55a05330f8cc	633	}
darran	0:55a05330f8cc	634
darran	0:55a05330f8cc	635	/**
darran	0:55a05330f8cc	636	* dns_check_entry() - see if pEntry has not yet been queried and, if so, sends out a query.
darran	0:55a05330f8cc	637	* Check an entry in the dns_table:
darran	0:55a05330f8cc	638	* - send out query for new entries
darran	0:55a05330f8cc	639	* - retry old pending entries on timeout (also with different servers)
darran	0:55a05330f8cc	640	* - remove completed entries from the table if their TTL has expired
darran	0:55a05330f8cc	641	*
darran	0:55a05330f8cc	642	* @param i index of the dns_table entry to check
darran	0:55a05330f8cc	643	*/
darran	0:55a05330f8cc	644	static void
darran	0:55a05330f8cc	645	dns_check_entry(u8_t i)
darran	0:55a05330f8cc	646	{
darran	0:55a05330f8cc	647	struct dns_table_entry *pEntry = &dns_table[i];
darran	0:55a05330f8cc	648
darran	0:55a05330f8cc	649	LWIP_ASSERT("array index out of bounds", i < DNS_TABLE_SIZE);
darran	0:55a05330f8cc	650
darran	0:55a05330f8cc	651	switch(pEntry->state) {
darran	0:55a05330f8cc	652
darran	0:55a05330f8cc	653	case DNS_STATE_NEW: {
darran	0:55a05330f8cc	654	/* initialize new entry */
darran	0:55a05330f8cc	655	pEntry->state = DNS_STATE_ASKING;
darran	0:55a05330f8cc	656	pEntry->numdns = 0;
darran	0:55a05330f8cc	657	pEntry->tmr = 1;
darran	0:55a05330f8cc	658	pEntry->retries = 0;
darran	0:55a05330f8cc	659
darran	0:55a05330f8cc	660	/* send DNS packet for this entry */
darran	0:55a05330f8cc	661	dns_send(pEntry->numdns, pEntry->name, i);
darran	0:55a05330f8cc	662	break;
darran	0:55a05330f8cc	663	}
darran	0:55a05330f8cc	664
darran	0:55a05330f8cc	665	case DNS_STATE_ASKING: {
darran	0:55a05330f8cc	666	if (--pEntry->tmr == 0) {
darran	0:55a05330f8cc	667	if (++pEntry->retries == DNS_MAX_RETRIES) {
darran	0:55a05330f8cc	668	if ((pEntry->numdns+1<DNS_MAX_SERVERS) && !ip_addr_isany(&dns_servers[pEntry->numdns+1])) {
darran	0:55a05330f8cc	669	/* change of server */
darran	0:55a05330f8cc	670	pEntry->numdns++;
darran	0:55a05330f8cc	671	pEntry->tmr = 1;
darran	0:55a05330f8cc	672	pEntry->retries = 0;
darran	0:55a05330f8cc	673	break;
darran	0:55a05330f8cc	674	} else {
darran	0:55a05330f8cc	675	LWIP_DEBUGF(DNS_DEBUG, ("dns_check_entry: \"%s\": timeout\n", pEntry->name));
darran	0:55a05330f8cc	676	/* call specified callback function if provided */
darran	0:55a05330f8cc	677	if (pEntry->found)
darran	0:55a05330f8cc	678	(*pEntry->found)(pEntry->name, NULL, pEntry->arg);
darran	0:55a05330f8cc	679	/* flush this entry */
darran	0:55a05330f8cc	680	pEntry->state = DNS_STATE_UNUSED;
darran	0:55a05330f8cc	681	pEntry->found = NULL;
darran	0:55a05330f8cc	682	break;
darran	0:55a05330f8cc	683	}
darran	0:55a05330f8cc	684	}
darran	0:55a05330f8cc	685
darran	0:55a05330f8cc	686	/* wait longer for the next retry */
darran	0:55a05330f8cc	687	pEntry->tmr = pEntry->retries;
darran	0:55a05330f8cc	688
darran	0:55a05330f8cc	689	/* send DNS packet for this entry */
darran	0:55a05330f8cc	690	dns_send(pEntry->numdns, pEntry->name, i);
darran	0:55a05330f8cc	691	}
darran	0:55a05330f8cc	692	break;
darran	0:55a05330f8cc	693	}
darran	0:55a05330f8cc	694
darran	0:55a05330f8cc	695	case DNS_STATE_DONE: {
darran	0:55a05330f8cc	696	/* if the time to live is nul */
darran	0:55a05330f8cc	697	if (--pEntry->ttl == 0) {
darran	0:55a05330f8cc	698	LWIP_DEBUGF(DNS_DEBUG, ("dns_check_entry: \"%s\": flush\n", pEntry->name));
darran	0:55a05330f8cc	699	/* flush this entry */
darran	0:55a05330f8cc	700	pEntry->state = DNS_STATE_UNUSED;
darran	0:55a05330f8cc	701	pEntry->found = NULL;
darran	0:55a05330f8cc	702	}
darran	0:55a05330f8cc	703	break;
darran	0:55a05330f8cc	704	}
darran	0:55a05330f8cc	705	case DNS_STATE_UNUSED:
darran	0:55a05330f8cc	706	/* nothing to do */
darran	0:55a05330f8cc	707	break;
darran	0:55a05330f8cc	708	default:
darran	0:55a05330f8cc	709	LWIP_ASSERT("unknown dns_table entry state:", 0);
darran	0:55a05330f8cc	710	break;
darran	0:55a05330f8cc	711	}
darran	0:55a05330f8cc	712	}
darran	0:55a05330f8cc	713
darran	0:55a05330f8cc	714	/**
darran	0:55a05330f8cc	715	* Call dns_check_entry for each entry in dns_table - check all entries.
darran	0:55a05330f8cc	716	*/
darran	0:55a05330f8cc	717	static void
darran	0:55a05330f8cc	718	dns_check_entries(void)
darran	0:55a05330f8cc	719	{
darran	0:55a05330f8cc	720	u8_t i;
darran	0:55a05330f8cc	721
darran	0:55a05330f8cc	722	for (i = 0; i < DNS_TABLE_SIZE; ++i) {
darran	0:55a05330f8cc	723	dns_check_entry(i);
darran	0:55a05330f8cc	724	}
darran	0:55a05330f8cc	725	}
darran	0:55a05330f8cc	726
darran	0:55a05330f8cc	727	/**
darran	0:55a05330f8cc	728	* Receive input function for DNS response packets arriving for the dns UDP pcb.
darran	0:55a05330f8cc	729	*
darran	0:55a05330f8cc	730	* @params see udp.h
darran	0:55a05330f8cc	731	*/
darran	0:55a05330f8cc	732	static void
darran	0:55a05330f8cc	733	dns_recv(void arg, struct udp_pcb pcb, struct pbuf p, ip_addr_t addr, u16_t port)
darran	0:55a05330f8cc	734	{
darran	0:55a05330f8cc	735	u16_t i;
darran	0:55a05330f8cc	736	char *pHostname;
darran	0:55a05330f8cc	737	struct dns_hdr *hdr;
darran	0:55a05330f8cc	738	struct dns_answer ans;
darran	0:55a05330f8cc	739	struct dns_table_entry *pEntry;
darran	0:55a05330f8cc	740	u16_t nquestions, nanswers;
darran	0:55a05330f8cc	741
darran	0:55a05330f8cc	742	LWIP_UNUSED_ARG(arg);
darran	0:55a05330f8cc	743	LWIP_UNUSED_ARG(pcb);
darran	0:55a05330f8cc	744	LWIP_UNUSED_ARG(addr);
darran	0:55a05330f8cc	745	LWIP_UNUSED_ARG(port);
darran	0:55a05330f8cc	746
darran	0:55a05330f8cc	747	/* is the dns message too big ? */
darran	0:55a05330f8cc	748	if (p->tot_len > DNS_MSG_SIZE) {
darran	0:55a05330f8cc	749	LWIP_DEBUGF(DNS_DEBUG, ("dns_recv: pbuf too big\n"));
darran	0:55a05330f8cc	750	/* free pbuf and return */
darran	0:55a05330f8cc	751	goto memerr;
darran	0:55a05330f8cc	752	}
darran	0:55a05330f8cc	753
darran	0:55a05330f8cc	754	/* is the dns message big enough ? */
darran	0:55a05330f8cc	755	if (p->tot_len < (SIZEOF_DNS_HDR + SIZEOF_DNS_QUERY + SIZEOF_DNS_ANSWER)) {
darran	0:55a05330f8cc	756	LWIP_DEBUGF(DNS_DEBUG, ("dns_recv: pbuf too small\n"));
darran	0:55a05330f8cc	757	/* free pbuf and return */
darran	0:55a05330f8cc	758	goto memerr;
darran	0:55a05330f8cc	759	}
darran	0:55a05330f8cc	760
darran	0:55a05330f8cc	761	/* copy dns payload inside static buffer for processing */
darran	0:55a05330f8cc	762	if (pbuf_copy_partial(p, dns_payload, p->tot_len, 0) == p->tot_len) {
darran	0:55a05330f8cc	763	/* The ID in the DNS header should be our entry into the name table. */
darran	0:55a05330f8cc	764	hdr = (struct dns_hdr*)dns_payload;
darran	0:55a05330f8cc	765	i = htons(hdr->id);
darran	0:55a05330f8cc	766	if (i < DNS_TABLE_SIZE) {
darran	0:55a05330f8cc	767	pEntry = &dns_table[i];
darran	0:55a05330f8cc	768	if(pEntry->state == DNS_STATE_ASKING) {
darran	0:55a05330f8cc	769	/* This entry is now completed. */
darran	0:55a05330f8cc	770	pEntry->state = DNS_STATE_DONE;
darran	0:55a05330f8cc	771	pEntry->err = hdr->flags2 & DNS_FLAG2_ERR_MASK;
darran	0:55a05330f8cc	772
darran	0:55a05330f8cc	773	/* We only care about the question(s) and the answers. The authrr
darran	0:55a05330f8cc	774	and the extrarr are simply discarded. */
darran	0:55a05330f8cc	775	nquestions = htons(hdr->numquestions);
darran	0:55a05330f8cc	776	nanswers = htons(hdr->numanswers);
darran	0:55a05330f8cc	777
darran	0:55a05330f8cc	778	/* Check for error. If so, call callback to inform. */
darran	0:55a05330f8cc	779	if (((hdr->flags1 & DNS_FLAG1_RESPONSE) == 0) \|\| (pEntry->err != 0) \|\| (nquestions != 1)) {
darran	0:55a05330f8cc	780	LWIP_DEBUGF(DNS_DEBUG, ("dns_recv: \"%s\": error in flags\n", pEntry->name));
darran	0:55a05330f8cc	781	/* call callback to indicate error, clean up memory and return */
darran	0:55a05330f8cc	782	goto responseerr;
darran	0:55a05330f8cc	783	}
darran	0:55a05330f8cc	784
darran	0:55a05330f8cc	785	#if DNS_DOES_NAME_CHECK
darran	0:55a05330f8cc	786	/* Check if the name in the "question" part match with the name in the entry. */
darran	0:55a05330f8cc	787	if (dns_compare_name((unsigned char )(pEntry->name), (unsigned char )dns_payload + SIZEOF_DNS_HDR) != 0) {
darran	0:55a05330f8cc	788	LWIP_DEBUGF(DNS_DEBUG, ("dns_recv: \"%s\": response not match to query\n", pEntry->name));
darran	0:55a05330f8cc	789	/* call callback to indicate error, clean up memory and return */
darran	0:55a05330f8cc	790	goto responseerr;
darran	0:55a05330f8cc	791	}
darran	0:55a05330f8cc	792	#endif /* DNS_DOES_NAME_CHECK */
darran	0:55a05330f8cc	793
darran	0:55a05330f8cc	794	/* Skip the name in the "question" part */
darran	0:55a05330f8cc	795	pHostname = (char ) dns_parse_name((unsigned char )dns_payload + SIZEOF_DNS_HDR) + SIZEOF_DNS_QUERY;
darran	0:55a05330f8cc	796
darran	0:55a05330f8cc	797	while (nanswers > 0) {
darran	0:55a05330f8cc	798	/* skip answer resource record's host name */
darran	0:55a05330f8cc	799	pHostname = (char ) dns_parse_name((unsigned char )pHostname);
darran	0:55a05330f8cc	800
darran	0:55a05330f8cc	801	/* Check for IP address type and Internet class. Others are discarded. */
darran	0:55a05330f8cc	802	SMEMCPY(&ans, pHostname, SIZEOF_DNS_ANSWER);
darran	0:55a05330f8cc	803	if((ans.type == htons(DNS_RRTYPE_A)) && (ans.cls == htons(DNS_RRCLASS_IN)) &&
darran	0:55a05330f8cc	804	(ans.len == htons(sizeof(ip_addr_t))) ) {
darran	0:55a05330f8cc	805	/* read the answer resource record's TTL, and maximize it if needed */
darran	0:55a05330f8cc	806	pEntry->ttl = ntohl(ans.ttl);
darran	0:55a05330f8cc	807	if (pEntry->ttl > DNS_MAX_TTL) {
darran	0:55a05330f8cc	808	pEntry->ttl = DNS_MAX_TTL;
darran	0:55a05330f8cc	809	}
darran	0:55a05330f8cc	810	/* read the IP address after answer resource record's header */
darran	0:55a05330f8cc	811	SMEMCPY(&(pEntry->ipaddr), (pHostname+SIZEOF_DNS_ANSWER), sizeof(ip_addr_t));
darran	0:55a05330f8cc	812	LWIP_DEBUGF(DNS_DEBUG, ("dns_recv: \"%s\": response = ", pEntry->name));
darran	0:55a05330f8cc	813	ip_addr_debug_print(DNS_DEBUG, (&(pEntry->ipaddr)));
darran	0:55a05330f8cc	814	LWIP_DEBUGF(DNS_DEBUG, ("\n"));
darran	0:55a05330f8cc	815	/* call specified callback function if provided */
darran	0:55a05330f8cc	816	if (pEntry->found) {
darran	0:55a05330f8cc	817	(*pEntry->found)(pEntry->name, &pEntry->ipaddr, pEntry->arg);
darran	0:55a05330f8cc	818	}
darran	0:55a05330f8cc	819	/* deallocate memory and return */
darran	0:55a05330f8cc	820	goto memerr;
darran	0:55a05330f8cc	821	} else {
darran	0:55a05330f8cc	822	pHostname = pHostname + SIZEOF_DNS_ANSWER + htons(ans.len);
darran	0:55a05330f8cc	823	}
darran	0:55a05330f8cc	824	--nanswers;
darran	0:55a05330f8cc	825	}
darran	0:55a05330f8cc	826	LWIP_DEBUGF(DNS_DEBUG, ("dns_recv: \"%s\": error in response\n", pEntry->name));
darran	0:55a05330f8cc	827	/* call callback to indicate error, clean up memory and return */
darran	0:55a05330f8cc	828	goto responseerr;
darran	0:55a05330f8cc	829	}
darran	0:55a05330f8cc	830	}
darran	0:55a05330f8cc	831	}
darran	0:55a05330f8cc	832
darran	0:55a05330f8cc	833	/* deallocate memory and return */
darran	0:55a05330f8cc	834	goto memerr;
darran	0:55a05330f8cc	835
darran	0:55a05330f8cc	836	responseerr:
darran	0:55a05330f8cc	837	/* ERROR: call specified callback function with NULL as name to indicate an error */
darran	0:55a05330f8cc	838	if (pEntry->found) {
darran	0:55a05330f8cc	839	(*pEntry->found)(pEntry->name, NULL, pEntry->arg);
darran	0:55a05330f8cc	840	}
darran	0:55a05330f8cc	841	/* flush this entry */
darran	0:55a05330f8cc	842	pEntry->state = DNS_STATE_UNUSED;
darran	0:55a05330f8cc	843	pEntry->found = NULL;
darran	0:55a05330f8cc	844
darran	0:55a05330f8cc	845	memerr:
darran	0:55a05330f8cc	846	/* free pbuf */
darran	0:55a05330f8cc	847	pbuf_free(p);
darran	0:55a05330f8cc	848	return;
darran	0:55a05330f8cc	849	}
darran	0:55a05330f8cc	850
darran	0:55a05330f8cc	851	/**
darran	0:55a05330f8cc	852	* Queues a new hostname to resolve and sends out a DNS query for that hostname
darran	0:55a05330f8cc	853	*
darran	0:55a05330f8cc	854	* @param name the hostname that is to be queried
darran	0:55a05330f8cc	855	* @param found a callback founction to be called on success, failure or timeout
darran	0:55a05330f8cc	856	* @param callback_arg argument to pass to the callback function
darran	0:55a05330f8cc	857	* @return @return a err_t return code.
darran	0:55a05330f8cc	858	*/
darran	0:55a05330f8cc	859	static err_t
darran	0:55a05330f8cc	860	dns_enqueue(const char name, dns_found_callback found, void callback_arg)
darran	0:55a05330f8cc	861	{
darran	0:55a05330f8cc	862	u8_t i;
darran	0:55a05330f8cc	863	u8_t lseq, lseqi;
darran	0:55a05330f8cc	864	struct dns_table_entry *pEntry = NULL;
darran	0:55a05330f8cc	865	size_t namelen;
darran	0:55a05330f8cc	866
darran	0:55a05330f8cc	867	/* search an unused entry, or the oldest one */
darran	0:55a05330f8cc	868	lseq = lseqi = 0;
darran	0:55a05330f8cc	869	for (i = 0; i < DNS_TABLE_SIZE; ++i) {
darran	0:55a05330f8cc	870	pEntry = &dns_table[i];
darran	0:55a05330f8cc	871	/* is it an unused entry ? */
darran	0:55a05330f8cc	872	if (pEntry->state == DNS_STATE_UNUSED)
darran	0:55a05330f8cc	873	break;
darran	0:55a05330f8cc	874
darran	0:55a05330f8cc	875	/* check if this is the oldest completed entry */
darran	0:55a05330f8cc	876	if (pEntry->state == DNS_STATE_DONE) {
darran	0:55a05330f8cc	877	if ((dns_seqno - pEntry->seqno) > lseq) {
darran	0:55a05330f8cc	878	lseq = dns_seqno - pEntry->seqno;
darran	0:55a05330f8cc	879	lseqi = i;
darran	0:55a05330f8cc	880	}
darran	0:55a05330f8cc	881	}
darran	0:55a05330f8cc	882	}
darran	0:55a05330f8cc	883
darran	0:55a05330f8cc	884	/* if we don't have found an unused entry, use the oldest completed one */
darran	0:55a05330f8cc	885	if (i == DNS_TABLE_SIZE) {
darran	0:55a05330f8cc	886	if ((lseqi >= DNS_TABLE_SIZE) \|\| (dns_table[lseqi].state != DNS_STATE_DONE)) {
darran	0:55a05330f8cc	887	/* no entry can't be used now, table is full */
darran	0:55a05330f8cc	888	LWIP_DEBUGF(DNS_DEBUG, ("dns_enqueue: \"%s\": DNS entries table is full\n", name));
darran	0:55a05330f8cc	889	return ERR_MEM;
darran	0:55a05330f8cc	890	} else {
darran	0:55a05330f8cc	891	/* use the oldest completed one */
darran	0:55a05330f8cc	892	i = lseqi;
darran	0:55a05330f8cc	893	pEntry = &dns_table[i];
darran	0:55a05330f8cc	894	}
darran	0:55a05330f8cc	895	}
darran	0:55a05330f8cc	896
darran	0:55a05330f8cc	897	/* use this entry */
darran	0:55a05330f8cc	898	LWIP_DEBUGF(DNS_DEBUG, ("dns_enqueue: \"%s\": use DNS entry %"U16_F"\n", name, (u16_t)(i)));
darran	0:55a05330f8cc	899
darran	0:55a05330f8cc	900	/* fill the entry */
darran	0:55a05330f8cc	901	pEntry->state = DNS_STATE_NEW;
darran	0:55a05330f8cc	902	pEntry->seqno = dns_seqno++;
darran	0:55a05330f8cc	903	pEntry->found = found;
darran	0:55a05330f8cc	904	pEntry->arg = callback_arg;
darran	0:55a05330f8cc	905	namelen = LWIP_MIN(strlen(name), DNS_MAX_NAME_LENGTH-1);
darran	0:55a05330f8cc	906	MEMCPY(pEntry->name, name, namelen);
darran	0:55a05330f8cc	907	pEntry->name[namelen] = 0;
darran	0:55a05330f8cc	908
darran	0:55a05330f8cc	909	/* force to send query without waiting timer */
darran	0:55a05330f8cc	910	dns_check_entry(i);
darran	0:55a05330f8cc	911
darran	0:55a05330f8cc	912	/* dns query is enqueued */
darran	0:55a05330f8cc	913	return ERR_INPROGRESS;
darran	0:55a05330f8cc	914	}
darran	0:55a05330f8cc	915
darran	0:55a05330f8cc	916	/**
darran	0:55a05330f8cc	917	* Resolve a hostname (string) into an IP address.
darran	0:55a05330f8cc	918	* NON-BLOCKING callback version for use with raw API!!!
darran	0:55a05330f8cc	919	*
darran	0:55a05330f8cc	920	* Returns immediately with one of err_t return codes:
darran	0:55a05330f8cc	921	* - ERR_OK if hostname is a valid IP address string or the host
darran	0:55a05330f8cc	922	* name is already in the local names table.
darran	0:55a05330f8cc	923	* - ERR_INPROGRESS enqueue a request to be sent to the DNS server
darran	0:55a05330f8cc	924	* for resolution if no errors are present.
darran	0:55a05330f8cc	925	*
darran	0:55a05330f8cc	926	* @param hostname the hostname that is to be queried
darran	0:55a05330f8cc	927	* @param addr pointer to a ip_addr_t where to store the address if it is already
darran	0:55a05330f8cc	928	* cached in the dns_table (only valid if ERR_OK is returned!)
darran	0:55a05330f8cc	929	* @param found a callback function to be called on success, failure or timeout (only if
darran	0:55a05330f8cc	930	* ERR_INPROGRESS is returned!)
darran	0:55a05330f8cc	931	* @param callback_arg argument to pass to the callback function
darran	0:55a05330f8cc	932	* @return a err_t return code.
darran	0:55a05330f8cc	933	*/
darran	0:55a05330f8cc	934	err_t
darran	0:55a05330f8cc	935	dns_gethostbyname(const char hostname, ip_addr_t addr, dns_found_callback found,
darran	0:55a05330f8cc	936	void *callback_arg)
darran	0:55a05330f8cc	937	{
darran	0:55a05330f8cc	938	u32_t ipaddr;
darran	0:55a05330f8cc	939	/* not initialized or no valid server yet, or invalid addr pointer
darran	0:55a05330f8cc	940	* or invalid hostname or invalid hostname length */
darran	0:55a05330f8cc	941	if ((dns_pcb == NULL) \|\| (addr == NULL) \|\|
darran	0:55a05330f8cc	942	(!hostname) \|\| (!hostname[0]) \|\|
darran	0:55a05330f8cc	943	(strlen(hostname) >= DNS_MAX_NAME_LENGTH)) {
darran	0:55a05330f8cc	944	return ERR_VAL;
darran	0:55a05330f8cc	945	}
darran	0:55a05330f8cc	946
darran	0:55a05330f8cc	947	#if LWIP_HAVE_LOOPIF
darran	0:55a05330f8cc	948	if (strcmp(hostname, "localhost")==0) {
darran	0:55a05330f8cc	949	ip_addr_set_loopback(addr);
darran	0:55a05330f8cc	950	return ERR_OK;
darran	0:55a05330f8cc	951	}
darran	0:55a05330f8cc	952	#endif /* LWIP_HAVE_LOOPIF */
darran	0:55a05330f8cc	953
darran	0:55a05330f8cc	954	/* host name already in octet notation? set ip addr and return ERR_OK */
darran	0:55a05330f8cc	955	ipaddr = ipaddr_addr(hostname);
darran	0:55a05330f8cc	956	if (ipaddr == IPADDR_NONE) {
darran	0:55a05330f8cc	957	/* already have this address cached? */
darran	0:55a05330f8cc	958	ipaddr = dns_lookup(hostname);
darran	0:55a05330f8cc	959	}
darran	0:55a05330f8cc	960	if (ipaddr != IPADDR_NONE) {
darran	0:55a05330f8cc	961	ip4_addr_set_u32(addr, ipaddr);
darran	0:55a05330f8cc	962	return ERR_OK;
darran	0:55a05330f8cc	963	}
darran	0:55a05330f8cc	964
darran	0:55a05330f8cc	965	/* queue query with specified callback */
darran	0:55a05330f8cc	966	return dns_enqueue(hostname, found, callback_arg);
darran	0:55a05330f8cc	967	}
darran	0:55a05330f8cc	968	#endif /* LWIP_DNS */

Repository toolbox

Export to desktop IDE

Build repository

Repository details

Type:	Program
Mbed OS support:	Mbed 2 deprecated
Created:	18 Jun 2010
Imports:	7
Forks:	0
Commits:	2
Dependents:	0
Dependencies:	1
Followers:	1

lwip/core/dns.c@0:55a05330f8cc, 2010-06-18 (annotated)

Who changed what in which revision?

Repository toolbox

Repository details

Important Information for this Arm website

Access Warning