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lwip/core/dns.c@0:281d6ff68967, 2010-11-19 (annotated)

Committer:: hexley
Date:: Fri Nov 19 01:54:45 2010 +0000
Revision:: 0:281d6ff68967

Who changed what in which revision?

User	Revision	Line number	New contents of line
hexley	0:281d6ff68967	1	/**
hexley	0:281d6ff68967	2	* @file
hexley	0:281d6ff68967	3	* DNS - host name to IP address resolver.
hexley	0:281d6ff68967	4	*
hexley	0:281d6ff68967	5	*/
hexley	0:281d6ff68967	6
hexley	0:281d6ff68967	7	/**
hexley	0:281d6ff68967	8
hexley	0:281d6ff68967	9	* This file implements a DNS host name to IP address resolver.
hexley	0:281d6ff68967	10
hexley	0:281d6ff68967	11	* Port to lwIP from uIP
hexley	0:281d6ff68967	12	* by Jim Pettinato April 2007
hexley	0:281d6ff68967	13
hexley	0:281d6ff68967	14	* uIP version Copyright (c) 2002-2003, Adam Dunkels.
hexley	0:281d6ff68967	15	* All rights reserved.
hexley	0:281d6ff68967	16	*
hexley	0:281d6ff68967	17	* Redistribution and use in source and binary forms, with or without
hexley	0:281d6ff68967	18	* modification, are permitted provided that the following conditions
hexley	0:281d6ff68967	19	* are met:
hexley	0:281d6ff68967	20	* 1. Redistributions of source code must retain the above copyright
hexley	0:281d6ff68967	21	* notice, this list of conditions and the following disclaimer.
hexley	0:281d6ff68967	22	* 2. Redistributions in binary form must reproduce the above copyright
hexley	0:281d6ff68967	23	* notice, this list of conditions and the following disclaimer in the
hexley	0:281d6ff68967	24	* documentation and/or other materials provided with the distribution.
hexley	0:281d6ff68967	25	* 3. The name of the author may not be used to endorse or promote
hexley	0:281d6ff68967	26	* products derived from this software without specific prior
hexley	0:281d6ff68967	27	* written permission.
hexley	0:281d6ff68967	28	*
hexley	0:281d6ff68967	29	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
hexley	0:281d6ff68967	30	* OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
hexley	0:281d6ff68967	31	* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
hexley	0:281d6ff68967	32	* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
hexley	0:281d6ff68967	33	* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
hexley	0:281d6ff68967	34	* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
hexley	0:281d6ff68967	35	* GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
hexley	0:281d6ff68967	36	* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
hexley	0:281d6ff68967	37	* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
hexley	0:281d6ff68967	38	* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
hexley	0:281d6ff68967	39	* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
hexley	0:281d6ff68967	40	*
hexley	0:281d6ff68967	41	*
hexley	0:281d6ff68967	42	* DNS.C
hexley	0:281d6ff68967	43	*
hexley	0:281d6ff68967	44	* The lwIP DNS resolver functions are used to lookup a host name and
hexley	0:281d6ff68967	45	* map it to a numerical IP address. It maintains a list of resolved
hexley	0:281d6ff68967	46	* hostnames that can be queried with the dns_lookup() function.
hexley	0:281d6ff68967	47	* New hostnames can be resolved using the dns_query() function.
hexley	0:281d6ff68967	48	*
hexley	0:281d6ff68967	49	* The lwIP version of the resolver also adds a non-blocking version of
hexley	0:281d6ff68967	50	* gethostbyname() that will work with a raw API application. This function
hexley	0:281d6ff68967	51	* checks for an IP address string first and converts it if it is valid.
hexley	0:281d6ff68967	52	* gethostbyname() then does a dns_lookup() to see if the name is
hexley	0:281d6ff68967	53	* already in the table. If so, the IP is returned. If not, a query is
hexley	0:281d6ff68967	54	* issued and the function returns with a ERR_INPROGRESS status. The app
hexley	0:281d6ff68967	55	* using the dns client must then go into a waiting state.
hexley	0:281d6ff68967	56	*
hexley	0:281d6ff68967	57	* Once a hostname has been resolved (or found to be non-existent),
hexley	0:281d6ff68967	58	* the resolver code calls a specified callback function (which
hexley	0:281d6ff68967	59	* must be implemented by the module that uses the resolver).
hexley	0:281d6ff68967	60	*/
hexley	0:281d6ff68967	61
hexley	0:281d6ff68967	62	/*-----------------------------------------------------------------------------
hexley	0:281d6ff68967	63	* RFC 1035 - Domain names - implementation and specification
hexley	0:281d6ff68967	64	* RFC 2181 - Clarifications to the DNS Specification
hexley	0:281d6ff68967	65	----------------------------------------------------------------------------/
hexley	0:281d6ff68967	66
hexley	0:281d6ff68967	67	/** @todo: define good default values (rfc compliance) */
hexley	0:281d6ff68967	68	/** @todo: improve answer parsing, more checkings... */
hexley	0:281d6ff68967	69	/** @todo: check RFC1035 - 7.3. Processing responses */
hexley	0:281d6ff68967	70
hexley	0:281d6ff68967	71	/*-----------------------------------------------------------------------------
hexley	0:281d6ff68967	72	* Includes
hexley	0:281d6ff68967	73	----------------------------------------------------------------------------/
hexley	0:281d6ff68967	74
hexley	0:281d6ff68967	75	#include "lwip/opt.h"
hexley	0:281d6ff68967	76
hexley	0:281d6ff68967	77	#if LWIP_DNS /* don't build if not configured for use in lwipopts.h */
hexley	0:281d6ff68967	78
hexley	0:281d6ff68967	79	#include "lwip/udp.h"
hexley	0:281d6ff68967	80	#include "lwip/mem.h"
hexley	0:281d6ff68967	81	#include "lwip/memp.h"
hexley	0:281d6ff68967	82	#include "lwip/dns.h"
hexley	0:281d6ff68967	83
hexley	0:281d6ff68967	84	#include <string.h>
hexley	0:281d6ff68967	85
hexley	0:281d6ff68967	86	/** DNS server IP address */
hexley	0:281d6ff68967	87	#ifndef DNS_SERVER_ADDRESS
hexley	0:281d6ff68967	88	#define DNS_SERVER_ADDRESS(ipaddr) (ip4_addr_set_u32(ipaddr, ipaddr_addr("208.67.222.222"))) /* resolver1.opendns.com */
hexley	0:281d6ff68967	89	#endif
hexley	0:281d6ff68967	90
hexley	0:281d6ff68967	91	/** DNS server port address */
hexley	0:281d6ff68967	92	#ifndef DNS_SERVER_PORT
hexley	0:281d6ff68967	93	#define DNS_SERVER_PORT 53
hexley	0:281d6ff68967	94	#endif
hexley	0:281d6ff68967	95
hexley	0:281d6ff68967	96	/** DNS maximum number of retries when asking for a name, before "timeout". */
hexley	0:281d6ff68967	97	#ifndef DNS_MAX_RETRIES
hexley	0:281d6ff68967	98	#define DNS_MAX_RETRIES 4
hexley	0:281d6ff68967	99	#endif
hexley	0:281d6ff68967	100
hexley	0:281d6ff68967	101	/** DNS resource record max. TTL (one week as default) */
hexley	0:281d6ff68967	102	#ifndef DNS_MAX_TTL
hexley	0:281d6ff68967	103	#define DNS_MAX_TTL 604800
hexley	0:281d6ff68967	104	#endif
hexley	0:281d6ff68967	105
hexley	0:281d6ff68967	106	/* DNS protocol flags */
hexley	0:281d6ff68967	107	#define DNS_FLAG1_RESPONSE 0x80
hexley	0:281d6ff68967	108	#define DNS_FLAG1_OPCODE_STATUS 0x10
hexley	0:281d6ff68967	109	#define DNS_FLAG1_OPCODE_INVERSE 0x08
hexley	0:281d6ff68967	110	#define DNS_FLAG1_OPCODE_STANDARD 0x00
hexley	0:281d6ff68967	111	#define DNS_FLAG1_AUTHORATIVE 0x04
hexley	0:281d6ff68967	112	#define DNS_FLAG1_TRUNC 0x02
hexley	0:281d6ff68967	113	#define DNS_FLAG1_RD 0x01
hexley	0:281d6ff68967	114	#define DNS_FLAG2_RA 0x80
hexley	0:281d6ff68967	115	#define DNS_FLAG2_ERR_MASK 0x0f
hexley	0:281d6ff68967	116	#define DNS_FLAG2_ERR_NONE 0x00
hexley	0:281d6ff68967	117	#define DNS_FLAG2_ERR_NAME 0x03
hexley	0:281d6ff68967	118
hexley	0:281d6ff68967	119	/* DNS protocol states */
hexley	0:281d6ff68967	120	#define DNS_STATE_UNUSED 0
hexley	0:281d6ff68967	121	#define DNS_STATE_NEW 1
hexley	0:281d6ff68967	122	#define DNS_STATE_ASKING 2
hexley	0:281d6ff68967	123	#define DNS_STATE_DONE 3
hexley	0:281d6ff68967	124
hexley	0:281d6ff68967	125	#ifdef PACK_STRUCT_USE_INCLUDES
hexley	0:281d6ff68967	126	# include "arch/bpstruct.h"
hexley	0:281d6ff68967	127	#endif
hexley	0:281d6ff68967	128	PACK_STRUCT_BEGIN
hexley	0:281d6ff68967	129	/** DNS message header */
hexley	0:281d6ff68967	130	struct dns_hdr {
hexley	0:281d6ff68967	131	PACK_STRUCT_FIELD(u16_t id);
hexley	0:281d6ff68967	132	PACK_STRUCT_FIELD(u8_t flags1);
hexley	0:281d6ff68967	133	PACK_STRUCT_FIELD(u8_t flags2);
hexley	0:281d6ff68967	134	PACK_STRUCT_FIELD(u16_t numquestions);
hexley	0:281d6ff68967	135	PACK_STRUCT_FIELD(u16_t numanswers);
hexley	0:281d6ff68967	136	PACK_STRUCT_FIELD(u16_t numauthrr);
hexley	0:281d6ff68967	137	PACK_STRUCT_FIELD(u16_t numextrarr);
hexley	0:281d6ff68967	138	} PACK_STRUCT_STRUCT;
hexley	0:281d6ff68967	139	PACK_STRUCT_END
hexley	0:281d6ff68967	140	#ifdef PACK_STRUCT_USE_INCLUDES
hexley	0:281d6ff68967	141	# include "arch/epstruct.h"
hexley	0:281d6ff68967	142	#endif
hexley	0:281d6ff68967	143	#define SIZEOF_DNS_HDR 12
hexley	0:281d6ff68967	144
hexley	0:281d6ff68967	145	/** DNS query message structure.
hexley	0:281d6ff68967	146	No packing needed: only used locally on the stack. */
hexley	0:281d6ff68967	147	struct dns_query {
hexley	0:281d6ff68967	148	/* DNS query record starts with either a domain name or a pointer
hexley	0:281d6ff68967	149	to a name already present somewhere in the packet. */
hexley	0:281d6ff68967	150	u16_t type;
hexley	0:281d6ff68967	151	u16_t cls;
hexley	0:281d6ff68967	152	};
hexley	0:281d6ff68967	153	#define SIZEOF_DNS_QUERY 4
hexley	0:281d6ff68967	154
hexley	0:281d6ff68967	155	/** DNS answer message structure.
hexley	0:281d6ff68967	156	No packing needed: only used locally on the stack. */
hexley	0:281d6ff68967	157	struct dns_answer {
hexley	0:281d6ff68967	158	/* DNS answer record starts with either a domain name or a pointer
hexley	0:281d6ff68967	159	to a name already present somewhere in the packet. */
hexley	0:281d6ff68967	160	u16_t type;
hexley	0:281d6ff68967	161	u16_t cls;
hexley	0:281d6ff68967	162	u32_t ttl;
hexley	0:281d6ff68967	163	u16_t len;
hexley	0:281d6ff68967	164	};
hexley	0:281d6ff68967	165	#define SIZEOF_DNS_ANSWER 10
hexley	0:281d6ff68967	166
hexley	0:281d6ff68967	167	/** DNS table entry */
hexley	0:281d6ff68967	168	struct dns_table_entry {
hexley	0:281d6ff68967	169	u8_t state;
hexley	0:281d6ff68967	170	u8_t numdns;
hexley	0:281d6ff68967	171	u8_t tmr;
hexley	0:281d6ff68967	172	u8_t retries;
hexley	0:281d6ff68967	173	u8_t seqno;
hexley	0:281d6ff68967	174	u8_t err;
hexley	0:281d6ff68967	175	u32_t ttl;
hexley	0:281d6ff68967	176	char name[DNS_MAX_NAME_LENGTH];
hexley	0:281d6ff68967	177	ip_addr_t ipaddr;
hexley	0:281d6ff68967	178	/* pointer to callback on DNS query done */
hexley	0:281d6ff68967	179	dns_found_callback found;
hexley	0:281d6ff68967	180	void *arg;
hexley	0:281d6ff68967	181	};
hexley	0:281d6ff68967	182
hexley	0:281d6ff68967	183	#if DNS_LOCAL_HOSTLIST
hexley	0:281d6ff68967	184
hexley	0:281d6ff68967	185	#if DNS_LOCAL_HOSTLIST_IS_DYNAMIC
hexley	0:281d6ff68967	186	/** Local host-list. For hostnames in this list, no
hexley	0:281d6ff68967	187	* external name resolution is performed */
hexley	0:281d6ff68967	188	static struct local_hostlist_entry *local_hostlist_dynamic;
hexley	0:281d6ff68967	189	#else /* DNS_LOCAL_HOSTLIST_IS_DYNAMIC */
hexley	0:281d6ff68967	190
hexley	0:281d6ff68967	191	/** Defining this allows the local_hostlist_static to be placed in a different
hexley	0:281d6ff68967	192	* linker section (e.g. FLASH) */
hexley	0:281d6ff68967	193	#ifndef DNS_LOCAL_HOSTLIST_STORAGE_PRE
hexley	0:281d6ff68967	194	#define DNS_LOCAL_HOSTLIST_STORAGE_PRE static
hexley	0:281d6ff68967	195	#endif /* DNS_LOCAL_HOSTLIST_STORAGE_PRE */
hexley	0:281d6ff68967	196	/** Defining this allows the local_hostlist_static to be placed in a different
hexley	0:281d6ff68967	197	* linker section (e.g. FLASH) */
hexley	0:281d6ff68967	198	#ifndef DNS_LOCAL_HOSTLIST_STORAGE_POST
hexley	0:281d6ff68967	199	#define DNS_LOCAL_HOSTLIST_STORAGE_POST
hexley	0:281d6ff68967	200	#endif /* DNS_LOCAL_HOSTLIST_STORAGE_POST */
hexley	0:281d6ff68967	201	DNS_LOCAL_HOSTLIST_STORAGE_PRE struct local_hostlist_entry local_hostlist_static[]
hexley	0:281d6ff68967	202	DNS_LOCAL_HOSTLIST_STORAGE_POST = DNS_LOCAL_HOSTLIST_INIT;
hexley	0:281d6ff68967	203
hexley	0:281d6ff68967	204	#endif /* DNS_LOCAL_HOSTLIST_IS_DYNAMIC */
hexley	0:281d6ff68967	205
hexley	0:281d6ff68967	206	static void dns_init_local();
hexley	0:281d6ff68967	207	#endif /* DNS_LOCAL_HOSTLIST */
hexley	0:281d6ff68967	208
hexley	0:281d6ff68967	209
hexley	0:281d6ff68967	210	/* forward declarations */
hexley	0:281d6ff68967	211	static void dns_recv(void s, struct udp_pcb pcb, struct pbuf p, ip_addr_t addr, u16_t port);
hexley	0:281d6ff68967	212	static void dns_check_entries(void);
hexley	0:281d6ff68967	213
hexley	0:281d6ff68967	214	/*-----------------------------------------------------------------------------
hexley	0:281d6ff68967	215	* Globales
hexley	0:281d6ff68967	216	----------------------------------------------------------------------------/
hexley	0:281d6ff68967	217
hexley	0:281d6ff68967	218	/* DNS variables */
hexley	0:281d6ff68967	219	static struct udp_pcb *dns_pcb;
hexley	0:281d6ff68967	220	static u8_t dns_seqno;
hexley	0:281d6ff68967	221	static struct dns_table_entry dns_table[DNS_TABLE_SIZE];
hexley	0:281d6ff68967	222	static ip_addr_t dns_servers[DNS_MAX_SERVERS];
hexley	0:281d6ff68967	223	/** Contiguous buffer for processing responses */
hexley	0:281d6ff68967	224	static u8_t dns_payload_buffer[LWIP_MEM_ALIGN_BUFFER(DNS_MSG_SIZE)];
hexley	0:281d6ff68967	225	static u8_t* dns_payload;
hexley	0:281d6ff68967	226
hexley	0:281d6ff68967	227	/**
hexley	0:281d6ff68967	228	* Initialize the resolver: set up the UDP pcb and configure the default server
hexley	0:281d6ff68967	229	* (DNS_SERVER_ADDRESS).
hexley	0:281d6ff68967	230	*/
hexley	0:281d6ff68967	231	void
hexley	0:281d6ff68967	232	dns_init()
hexley	0:281d6ff68967	233	{
hexley	0:281d6ff68967	234	ip_addr_t dnsserver;
hexley	0:281d6ff68967	235
hexley	0:281d6ff68967	236	dns_payload = (u8_t *)LWIP_MEM_ALIGN(dns_payload_buffer);
hexley	0:281d6ff68967	237
hexley	0:281d6ff68967	238	/* initialize default DNS server address */
hexley	0:281d6ff68967	239	DNS_SERVER_ADDRESS(&dnsserver);
hexley	0:281d6ff68967	240
hexley	0:281d6ff68967	241	LWIP_DEBUGF(DNS_DEBUG, ("dns_init: initializing\n"));
hexley	0:281d6ff68967	242
hexley	0:281d6ff68967	243	/* if dns client not yet initialized... */
hexley	0:281d6ff68967	244	if (dns_pcb == NULL) {
hexley	0:281d6ff68967	245	dns_pcb = udp_new();
hexley	0:281d6ff68967	246
hexley	0:281d6ff68967	247	if (dns_pcb != NULL) {
hexley	0:281d6ff68967	248	/* initialize DNS table not needed (initialized to zero since it is a
hexley	0:281d6ff68967	249	* global variable) */
hexley	0:281d6ff68967	250	LWIP_ASSERT("For implicit initialization to work, DNS_STATE_UNUSED needs to be 0",
hexley	0:281d6ff68967	251	DNS_STATE_UNUSED == 0);
hexley	0:281d6ff68967	252
hexley	0:281d6ff68967	253	/* initialize DNS client */
hexley	0:281d6ff68967	254	udp_bind(dns_pcb, IP_ADDR_ANY, 0);
hexley	0:281d6ff68967	255	udp_recv(dns_pcb, dns_recv, NULL);
hexley	0:281d6ff68967	256
hexley	0:281d6ff68967	257	/* initialize default DNS primary server */
hexley	0:281d6ff68967	258	dns_setserver(0, &dnsserver);
hexley	0:281d6ff68967	259	}
hexley	0:281d6ff68967	260	}
hexley	0:281d6ff68967	261	#if DNS_LOCAL_HOSTLIST
hexley	0:281d6ff68967	262	dns_init_local();
hexley	0:281d6ff68967	263	#endif
hexley	0:281d6ff68967	264	}
hexley	0:281d6ff68967	265
hexley	0:281d6ff68967	266	/**
hexley	0:281d6ff68967	267	* Initialize one of the DNS servers.
hexley	0:281d6ff68967	268	*
hexley	0:281d6ff68967	269	* @param numdns the index of the DNS server to set must be < DNS_MAX_SERVERS
hexley	0:281d6ff68967	270	* @param dnsserver IP address of the DNS server to set
hexley	0:281d6ff68967	271	*/
hexley	0:281d6ff68967	272	void
hexley	0:281d6ff68967	273	dns_setserver(u8_t numdns, ip_addr_t *dnsserver)
hexley	0:281d6ff68967	274	{
hexley	0:281d6ff68967	275	if ((numdns < DNS_MAX_SERVERS) && (dns_pcb != NULL) &&
hexley	0:281d6ff68967	276	(dnsserver != NULL) && !ip_addr_isany(dnsserver)) {
hexley	0:281d6ff68967	277	dns_servers[numdns] = (*dnsserver);
hexley	0:281d6ff68967	278	}
hexley	0:281d6ff68967	279	}
hexley	0:281d6ff68967	280
hexley	0:281d6ff68967	281	/**
hexley	0:281d6ff68967	282	* Obtain one of the currently configured DNS server.
hexley	0:281d6ff68967	283	*
hexley	0:281d6ff68967	284	* @param numdns the index of the DNS server
hexley	0:281d6ff68967	285	* @return IP address of the indexed DNS server or "ip_addr_any" if the DNS
hexley	0:281d6ff68967	286	* server has not been configured.
hexley	0:281d6ff68967	287	*/
hexley	0:281d6ff68967	288	ip_addr_t
hexley	0:281d6ff68967	289	dns_getserver(u8_t numdns)
hexley	0:281d6ff68967	290	{
hexley	0:281d6ff68967	291	if (numdns < DNS_MAX_SERVERS) {
hexley	0:281d6ff68967	292	return dns_servers[numdns];
hexley	0:281d6ff68967	293	} else {
hexley	0:281d6ff68967	294	return *IP_ADDR_ANY;
hexley	0:281d6ff68967	295	}
hexley	0:281d6ff68967	296	}
hexley	0:281d6ff68967	297
hexley	0:281d6ff68967	298	/**
hexley	0:281d6ff68967	299	* The DNS resolver client timer - handle retries and timeouts and should
hexley	0:281d6ff68967	300	* be called every DNS_TMR_INTERVAL milliseconds (every second by default).
hexley	0:281d6ff68967	301	*/
hexley	0:281d6ff68967	302	void
hexley	0:281d6ff68967	303	dns_tmr(void)
hexley	0:281d6ff68967	304	{
hexley	0:281d6ff68967	305	if (dns_pcb != NULL) {
hexley	0:281d6ff68967	306	LWIP_DEBUGF(DNS_DEBUG, ("dns_tmr: dns_check_entries\n"));
hexley	0:281d6ff68967	307	dns_check_entries();
hexley	0:281d6ff68967	308	}
hexley	0:281d6ff68967	309	}
hexley	0:281d6ff68967	310
hexley	0:281d6ff68967	311	#if DNS_LOCAL_HOSTLIST
hexley	0:281d6ff68967	312	static void
hexley	0:281d6ff68967	313	dns_init_local()
hexley	0:281d6ff68967	314	{
hexley	0:281d6ff68967	315	#if DNS_LOCAL_HOSTLIST_IS_DYNAMIC && defined(DNS_LOCAL_HOSTLIST_INIT)
hexley	0:281d6ff68967	316	int i;
hexley	0:281d6ff68967	317	struct local_hostlist_entry *entry;
hexley	0:281d6ff68967	318	/* Dynamic: copy entries from DNS_LOCAL_HOSTLIST_INIT to list */
hexley	0:281d6ff68967	319	struct local_hostlist_entry local_hostlist_init[] = DNS_LOCAL_HOSTLIST_INIT;
hexley	0:281d6ff68967	320	size_t namelen;
hexley	0:281d6ff68967	321	for (i = 0; i < sizeof(local_hostlist_init) / sizeof(struct local_hostlist_entry); i++) {
hexley	0:281d6ff68967	322	struct local_hostlist_entry *init_entry = &local_hostlist_init[i];
hexley	0:281d6ff68967	323	LWIP_ASSERT("invalid host name (NULL)", init_entry->name != NULL);
hexley	0:281d6ff68967	324	namelen = strlen(init_entry->name);
hexley	0:281d6ff68967	325	LWIP_ASSERT("namelen <= DNS_LOCAL_HOSTLIST_MAX_NAMELEN", namelen <= DNS_LOCAL_HOSTLIST_MAX_NAMELEN);
hexley	0:281d6ff68967	326	entry = (struct local_hostlist_entry *)memp_malloc(MEMP_LOCALHOSTLIST);
hexley	0:281d6ff68967	327	LWIP_ASSERT("mem-error in dns_init_local", entry != NULL);
hexley	0:281d6ff68967	328	if (entry != NULL) {
hexley	0:281d6ff68967	329	entry->name = (char*)entry + sizeof(struct local_hostlist_entry);
hexley	0:281d6ff68967	330	MEMCPY((char*)entry->name, init_entry->name, namelen);
hexley	0:281d6ff68967	331	((char*)entry->name)[namelen] = 0;
hexley	0:281d6ff68967	332	entry->addr = init_entry->addr;
hexley	0:281d6ff68967	333	entry->next = local_hostlist_dynamic;
hexley	0:281d6ff68967	334	local_hostlist_dynamic = entry;
hexley	0:281d6ff68967	335	}
hexley	0:281d6ff68967	336	}
hexley	0:281d6ff68967	337	#endif /* DNS_LOCAL_HOSTLIST_IS_DYNAMIC && defined(DNS_LOCAL_HOSTLIST_INIT) */
hexley	0:281d6ff68967	338	}
hexley	0:281d6ff68967	339
hexley	0:281d6ff68967	340	/**
hexley	0:281d6ff68967	341	* Scans the local host-list for a hostname.
hexley	0:281d6ff68967	342	*
hexley	0:281d6ff68967	343	* @param hostname Hostname to look for in the local host-list
hexley	0:281d6ff68967	344	* @return The first IP address for the hostname in the local host-list or
hexley	0:281d6ff68967	345	* IPADDR_NONE if not found.
hexley	0:281d6ff68967	346	*/
hexley	0:281d6ff68967	347	static u32_t
hexley	0:281d6ff68967	348	dns_lookup_local(const char *hostname)
hexley	0:281d6ff68967	349	{
hexley	0:281d6ff68967	350	#if DNS_LOCAL_HOSTLIST_IS_DYNAMIC
hexley	0:281d6ff68967	351	struct local_hostlist_entry *entry = local_hostlist_dynamic;
hexley	0:281d6ff68967	352	while(entry != NULL) {
hexley	0:281d6ff68967	353	if(strcmp(entry->name, hostname) == 0) {
hexley	0:281d6ff68967	354	return ip4_addr_get_u32(&entry->addr);
hexley	0:281d6ff68967	355	}
hexley	0:281d6ff68967	356	entry = entry->next;
hexley	0:281d6ff68967	357	}
hexley	0:281d6ff68967	358	#else /* DNS_LOCAL_HOSTLIST_IS_DYNAMIC */
hexley	0:281d6ff68967	359	int i;
hexley	0:281d6ff68967	360	for (i = 0; i < sizeof(local_hostlist_static) / sizeof(struct local_hostlist_entry); i++) {
hexley	0:281d6ff68967	361	if(strcmp(local_hostlist_static[i].name, hostname) == 0) {
hexley	0:281d6ff68967	362	return ip4_addr_get_u32(&local_hostlist_static[i].addr);
hexley	0:281d6ff68967	363	}
hexley	0:281d6ff68967	364	}
hexley	0:281d6ff68967	365	#endif /* DNS_LOCAL_HOSTLIST_IS_DYNAMIC */
hexley	0:281d6ff68967	366	return IPADDR_NONE;
hexley	0:281d6ff68967	367	}
hexley	0:281d6ff68967	368
hexley	0:281d6ff68967	369	#if DNS_LOCAL_HOSTLIST_IS_DYNAMIC
hexley	0:281d6ff68967	370	/** Remove all entries from the local host-list for a specific hostname
hexley	0:281d6ff68967	371	* and/or IP addess
hexley	0:281d6ff68967	372	*
hexley	0:281d6ff68967	373	* @param hostname hostname for which entries shall be removed from the local
hexley	0:281d6ff68967	374	* host-list
hexley	0:281d6ff68967	375	* @param addr address for which entries shall be removed from the local host-list
hexley	0:281d6ff68967	376	* @return the number of removed entries
hexley	0:281d6ff68967	377	*/
hexley	0:281d6ff68967	378	int
hexley	0:281d6ff68967	379	dns_local_removehost(const char hostname, const ip_addr_t addr)
hexley	0:281d6ff68967	380	{
hexley	0:281d6ff68967	381	int removed = 0;
hexley	0:281d6ff68967	382	struct local_hostlist_entry *entry = local_hostlist_dynamic;
hexley	0:281d6ff68967	383	struct local_hostlist_entry *last_entry = NULL;
hexley	0:281d6ff68967	384	while (entry != NULL) {
hexley	0:281d6ff68967	385	if (((hostname == NULL) \|\| !strcmp(entry->name, hostname)) &&
hexley	0:281d6ff68967	386	((addr == NULL) \|\| ip_addr_cmp(&entry->addr, addr))) {
hexley	0:281d6ff68967	387	struct local_hostlist_entry *free_entry;
hexley	0:281d6ff68967	388	if (last_entry != NULL) {
hexley	0:281d6ff68967	389	last_entry->next = entry->next;
hexley	0:281d6ff68967	390	} else {
hexley	0:281d6ff68967	391	local_hostlist_dynamic = entry->next;
hexley	0:281d6ff68967	392	}
hexley	0:281d6ff68967	393	free_entry = entry;
hexley	0:281d6ff68967	394	entry = entry->next;
hexley	0:281d6ff68967	395	memp_free(MEMP_LOCALHOSTLIST, free_entry);
hexley	0:281d6ff68967	396	removed++;
hexley	0:281d6ff68967	397	} else {
hexley	0:281d6ff68967	398	last_entry = entry;
hexley	0:281d6ff68967	399	entry = entry->next;
hexley	0:281d6ff68967	400	}
hexley	0:281d6ff68967	401	}
hexley	0:281d6ff68967	402	return removed;
hexley	0:281d6ff68967	403	}
hexley	0:281d6ff68967	404
hexley	0:281d6ff68967	405	/**
hexley	0:281d6ff68967	406	* Add a hostname/IP address pair to the local host-list.
hexley	0:281d6ff68967	407	* Duplicates are not checked.
hexley	0:281d6ff68967	408	*
hexley	0:281d6ff68967	409	* @param hostname hostname of the new entry
hexley	0:281d6ff68967	410	* @param addr IP address of the new entry
hexley	0:281d6ff68967	411	* @return ERR_OK if succeeded or ERR_MEM on memory error
hexley	0:281d6ff68967	412	*/
hexley	0:281d6ff68967	413	err_t
hexley	0:281d6ff68967	414	dns_local_addhost(const char hostname, const ip_addr_t addr)
hexley	0:281d6ff68967	415	{
hexley	0:281d6ff68967	416	struct local_hostlist_entry *entry;
hexley	0:281d6ff68967	417	size_t namelen;
hexley	0:281d6ff68967	418	LWIP_ASSERT("invalid host name (NULL)", hostname != NULL);
hexley	0:281d6ff68967	419	namelen = strlen(hostname);
hexley	0:281d6ff68967	420	LWIP_ASSERT("namelen <= DNS_LOCAL_HOSTLIST_MAX_NAMELEN", namelen <= DNS_LOCAL_HOSTLIST_MAX_NAMELEN);
hexley	0:281d6ff68967	421	entry = (struct local_hostlist_entry *)memp_malloc(MEMP_LOCALHOSTLIST);
hexley	0:281d6ff68967	422	if (entry == NULL) {
hexley	0:281d6ff68967	423	return ERR_MEM;
hexley	0:281d6ff68967	424	}
hexley	0:281d6ff68967	425	entry->name = (char*)entry + sizeof(struct local_hostlist_entry);
hexley	0:281d6ff68967	426	MEMCPY((char*)entry->name, hostname, namelen);
hexley	0:281d6ff68967	427	((char*)entry->name)[namelen] = 0;
hexley	0:281d6ff68967	428	ip_addr_copy(entry->addr, *addr);
hexley	0:281d6ff68967	429	entry->next = local_hostlist_dynamic;
hexley	0:281d6ff68967	430	local_hostlist_dynamic = entry;
hexley	0:281d6ff68967	431	return ERR_OK;
hexley	0:281d6ff68967	432	}
hexley	0:281d6ff68967	433	#endif /* DNS_LOCAL_HOSTLIST_IS_DYNAMIC*/
hexley	0:281d6ff68967	434	#endif /* DNS_LOCAL_HOSTLIST */
hexley	0:281d6ff68967	435
hexley	0:281d6ff68967	436	/**
hexley	0:281d6ff68967	437	* Look up a hostname in the array of known hostnames.
hexley	0:281d6ff68967	438	*
hexley	0:281d6ff68967	439	* @note This function only looks in the internal array of known
hexley	0:281d6ff68967	440	* hostnames, it does not send out a query for the hostname if none
hexley	0:281d6ff68967	441	* was found. The function dns_enqueue() can be used to send a query
hexley	0:281d6ff68967	442	* for a hostname.
hexley	0:281d6ff68967	443	*
hexley	0:281d6ff68967	444	* @param name the hostname to look up
hexley	0:281d6ff68967	445	* @return the hostname's IP address, as u32_t (instead of ip_addr_t to
hexley	0:281d6ff68967	446	* better check for failure: != IPADDR_NONE) or IPADDR_NONE if the hostname
hexley	0:281d6ff68967	447	* was not found in the cached dns_table.
hexley	0:281d6ff68967	448	*/
hexley	0:281d6ff68967	449	static u32_t
hexley	0:281d6ff68967	450	dns_lookup(const char *name)
hexley	0:281d6ff68967	451	{
hexley	0:281d6ff68967	452	u8_t i;
hexley	0:281d6ff68967	453	#if DNS_LOCAL_HOSTLIST \|\| defined(DNS_LOOKUP_LOCAL_EXTERN)
hexley	0:281d6ff68967	454	u32_t addr;
hexley	0:281d6ff68967	455	#endif /* DNS_LOCAL_HOSTLIST \|\| defined(DNS_LOOKUP_LOCAL_EXTERN) */
hexley	0:281d6ff68967	456	#if DNS_LOCAL_HOSTLIST
hexley	0:281d6ff68967	457	if ((addr = dns_lookup_local(name)) != IPADDR_NONE) {
hexley	0:281d6ff68967	458	return addr;
hexley	0:281d6ff68967	459	}
hexley	0:281d6ff68967	460	#endif /* DNS_LOCAL_HOSTLIST */
hexley	0:281d6ff68967	461	#ifdef DNS_LOOKUP_LOCAL_EXTERN
hexley	0:281d6ff68967	462	if((addr = DNS_LOOKUP_LOCAL_EXTERN(name)) != IPADDR_NONE) {
hexley	0:281d6ff68967	463	return addr;
hexley	0:281d6ff68967	464	}
hexley	0:281d6ff68967	465	#endif /* DNS_LOOKUP_LOCAL_EXTERN */
hexley	0:281d6ff68967	466
hexley	0:281d6ff68967	467	/* Walk through name list, return entry if found. If not, return NULL. */
hexley	0:281d6ff68967	468	for (i = 0; i < DNS_TABLE_SIZE; ++i) {
hexley	0:281d6ff68967	469	if ((dns_table[i].state == DNS_STATE_DONE) &&
hexley	0:281d6ff68967	470	(strcmp(name, dns_table[i].name) == 0)) {
hexley	0:281d6ff68967	471	LWIP_DEBUGF(DNS_DEBUG, ("dns_lookup: \"%s\": found = ", name));
hexley	0:281d6ff68967	472	ip_addr_debug_print(DNS_DEBUG, &(dns_table[i].ipaddr));
hexley	0:281d6ff68967	473	LWIP_DEBUGF(DNS_DEBUG, ("\n"));
hexley	0:281d6ff68967	474	return ip4_addr_get_u32(&dns_table[i].ipaddr);
hexley	0:281d6ff68967	475	}
hexley	0:281d6ff68967	476	}
hexley	0:281d6ff68967	477
hexley	0:281d6ff68967	478	return IPADDR_NONE;
hexley	0:281d6ff68967	479	}
hexley	0:281d6ff68967	480
hexley	0:281d6ff68967	481	#if DNS_DOES_NAME_CHECK
hexley	0:281d6ff68967	482	/**
hexley	0:281d6ff68967	483	* Compare the "dotted" name "query" with the encoded name "response"
hexley	0:281d6ff68967	484	* to make sure an answer from the DNS server matches the current dns_table
hexley	0:281d6ff68967	485	* entry (otherwise, answers might arrive late for hostname not on the list
hexley	0:281d6ff68967	486	* any more).
hexley	0:281d6ff68967	487	*
hexley	0:281d6ff68967	488	* @param query hostname (not encoded) from the dns_table
hexley	0:281d6ff68967	489	* @param response encoded hostname in the DNS response
hexley	0:281d6ff68967	490	* @return 0: names equal; 1: names differ
hexley	0:281d6ff68967	491	*/
hexley	0:281d6ff68967	492	static u8_t
hexley	0:281d6ff68967	493	dns_compare_name(unsigned char query, unsigned char response)
hexley	0:281d6ff68967	494	{
hexley	0:281d6ff68967	495	unsigned char n;
hexley	0:281d6ff68967	496
hexley	0:281d6ff68967	497	do {
hexley	0:281d6ff68967	498	n = *response++;
hexley	0:281d6ff68967	499	/** @see RFC 1035 - 4.1.4. Message compression */
hexley	0:281d6ff68967	500	if ((n & 0xc0) == 0xc0) {
hexley	0:281d6ff68967	501	/* Compressed name */
hexley	0:281d6ff68967	502	break;
hexley	0:281d6ff68967	503	} else {
hexley	0:281d6ff68967	504	/* Not compressed name */
hexley	0:281d6ff68967	505	while (n > 0) {
hexley	0:281d6ff68967	506	if ((query) != (response)) {
hexley	0:281d6ff68967	507	return 1;
hexley	0:281d6ff68967	508	}
hexley	0:281d6ff68967	509	++response;
hexley	0:281d6ff68967	510	++query;
hexley	0:281d6ff68967	511	--n;
hexley	0:281d6ff68967	512	};
hexley	0:281d6ff68967	513	++query;
hexley	0:281d6ff68967	514	}
hexley	0:281d6ff68967	515	} while (*response != 0);
hexley	0:281d6ff68967	516
hexley	0:281d6ff68967	517	return 0;
hexley	0:281d6ff68967	518	}
hexley	0:281d6ff68967	519	#endif /* DNS_DOES_NAME_CHECK */
hexley	0:281d6ff68967	520
hexley	0:281d6ff68967	521	/**
hexley	0:281d6ff68967	522	* Walk through a compact encoded DNS name and return the end of the name.
hexley	0:281d6ff68967	523	*
hexley	0:281d6ff68967	524	* @param query encoded DNS name in the DNS server response
hexley	0:281d6ff68967	525	* @return end of the name
hexley	0:281d6ff68967	526	*/
hexley	0:281d6ff68967	527	static unsigned char *
hexley	0:281d6ff68967	528	dns_parse_name(unsigned char *query)
hexley	0:281d6ff68967	529	{
hexley	0:281d6ff68967	530	unsigned char n;
hexley	0:281d6ff68967	531
hexley	0:281d6ff68967	532	do {
hexley	0:281d6ff68967	533	n = *query++;
hexley	0:281d6ff68967	534	/** @see RFC 1035 - 4.1.4. Message compression */
hexley	0:281d6ff68967	535	if ((n & 0xc0) == 0xc0) {
hexley	0:281d6ff68967	536	/* Compressed name */
hexley	0:281d6ff68967	537	break;
hexley	0:281d6ff68967	538	} else {
hexley	0:281d6ff68967	539	/* Not compressed name */
hexley	0:281d6ff68967	540	while (n > 0) {
hexley	0:281d6ff68967	541	++query;
hexley	0:281d6ff68967	542	--n;
hexley	0:281d6ff68967	543	};
hexley	0:281d6ff68967	544	}
hexley	0:281d6ff68967	545	} while (*query != 0);
hexley	0:281d6ff68967	546
hexley	0:281d6ff68967	547	return query + 1;
hexley	0:281d6ff68967	548	}
hexley	0:281d6ff68967	549
hexley	0:281d6ff68967	550	/**
hexley	0:281d6ff68967	551	* Send a DNS query packet.
hexley	0:281d6ff68967	552	*
hexley	0:281d6ff68967	553	* @param numdns index of the DNS server in the dns_servers table
hexley	0:281d6ff68967	554	* @param name hostname to query
hexley	0:281d6ff68967	555	* @param id index of the hostname in dns_table, used as transaction ID in the
hexley	0:281d6ff68967	556	* DNS query packet
hexley	0:281d6ff68967	557	* @return ERR_OK if packet is sent; an err_t indicating the problem otherwise
hexley	0:281d6ff68967	558	*/
hexley	0:281d6ff68967	559	static err_t
hexley	0:281d6ff68967	560	dns_send(u8_t numdns, const char* name, u8_t id)
hexley	0:281d6ff68967	561	{
hexley	0:281d6ff68967	562	err_t err;
hexley	0:281d6ff68967	563	struct dns_hdr *hdr;
hexley	0:281d6ff68967	564	struct dns_query qry;
hexley	0:281d6ff68967	565	struct pbuf *p;
hexley	0:281d6ff68967	566	char query, nptr;
hexley	0:281d6ff68967	567	const char *pHostname;
hexley	0:281d6ff68967	568	u8_t n;
hexley	0:281d6ff68967	569
hexley	0:281d6ff68967	570	LWIP_DEBUGF(DNS_DEBUG, ("dns_send: dns_servers[%"U16_F"] \"%s\": request\n",
hexley	0:281d6ff68967	571	(u16_t)(numdns), name));
hexley	0:281d6ff68967	572	LWIP_ASSERT("dns server out of array", numdns < DNS_MAX_SERVERS);
hexley	0:281d6ff68967	573	LWIP_ASSERT("dns server has no IP address set", !ip_addr_isany(&dns_servers[numdns]));
hexley	0:281d6ff68967	574
hexley	0:281d6ff68967	575	/* if here, we have either a new query or a retry on a previous query to process */
hexley	0:281d6ff68967	576	p = pbuf_alloc(PBUF_TRANSPORT, SIZEOF_DNS_HDR + DNS_MAX_NAME_LENGTH +
hexley	0:281d6ff68967	577	SIZEOF_DNS_QUERY, PBUF_RAM);
hexley	0:281d6ff68967	578	if (p != NULL) {
hexley	0:281d6ff68967	579	LWIP_ASSERT("pbuf must be in one piece", p->next == NULL);
hexley	0:281d6ff68967	580	/* fill dns header */
hexley	0:281d6ff68967	581	hdr = (struct dns_hdr*)p->payload;
hexley	0:281d6ff68967	582	memset(hdr, 0, SIZEOF_DNS_HDR);
hexley	0:281d6ff68967	583	hdr->id = htons(id);
hexley	0:281d6ff68967	584	hdr->flags1 = DNS_FLAG1_RD;
hexley	0:281d6ff68967	585	hdr->numquestions = PP_HTONS(1);
hexley	0:281d6ff68967	586	query = (char*)hdr + SIZEOF_DNS_HDR;
hexley	0:281d6ff68967	587	pHostname = name;
hexley	0:281d6ff68967	588	--pHostname;
hexley	0:281d6ff68967	589
hexley	0:281d6ff68967	590	/* convert hostname into suitable query format. */
hexley	0:281d6ff68967	591	do {
hexley	0:281d6ff68967	592	++pHostname;
hexley	0:281d6ff68967	593	nptr = query;
hexley	0:281d6ff68967	594	++query;
hexley	0:281d6ff68967	595	for(n = 0; pHostname != '.' && pHostname != 0; ++pHostname) {
hexley	0:281d6ff68967	596	query = pHostname;
hexley	0:281d6ff68967	597	++query;
hexley	0:281d6ff68967	598	++n;
hexley	0:281d6ff68967	599	}
hexley	0:281d6ff68967	600	*nptr = n;
hexley	0:281d6ff68967	601	} while(*pHostname != 0);
hexley	0:281d6ff68967	602	*query++='\0';
hexley	0:281d6ff68967	603
hexley	0:281d6ff68967	604	/* fill dns query */
hexley	0:281d6ff68967	605	qry.type = PP_HTONS(DNS_RRTYPE_A);
hexley	0:281d6ff68967	606	qry.cls = PP_HTONS(DNS_RRCLASS_IN);
hexley	0:281d6ff68967	607	SMEMCPY(query, &qry, SIZEOF_DNS_QUERY);
hexley	0:281d6ff68967	608
hexley	0:281d6ff68967	609	/* resize pbuf to the exact dns query */
hexley	0:281d6ff68967	610	pbuf_realloc(p, (u16_t)((query + SIZEOF_DNS_QUERY) - ((char*)(p->payload))));
hexley	0:281d6ff68967	611
hexley	0:281d6ff68967	612	/* connect to the server for faster receiving */
hexley	0:281d6ff68967	613	udp_connect(dns_pcb, &dns_servers[numdns], DNS_SERVER_PORT);
hexley	0:281d6ff68967	614	/* send dns packet */
hexley	0:281d6ff68967	615	err = udp_sendto(dns_pcb, p, &dns_servers[numdns], DNS_SERVER_PORT);
hexley	0:281d6ff68967	616
hexley	0:281d6ff68967	617	/* free pbuf */
hexley	0:281d6ff68967	618	pbuf_free(p);
hexley	0:281d6ff68967	619	} else {
hexley	0:281d6ff68967	620	err = ERR_MEM;
hexley	0:281d6ff68967	621	}
hexley	0:281d6ff68967	622
hexley	0:281d6ff68967	623	return err;
hexley	0:281d6ff68967	624	}
hexley	0:281d6ff68967	625
hexley	0:281d6ff68967	626	/**
hexley	0:281d6ff68967	627	* dns_check_entry() - see if pEntry has not yet been queried and, if so, sends out a query.
hexley	0:281d6ff68967	628	* Check an entry in the dns_table:
hexley	0:281d6ff68967	629	* - send out query for new entries
hexley	0:281d6ff68967	630	* - retry old pending entries on timeout (also with different servers)
hexley	0:281d6ff68967	631	* - remove completed entries from the table if their TTL has expired
hexley	0:281d6ff68967	632	*
hexley	0:281d6ff68967	633	* @param i index of the dns_table entry to check
hexley	0:281d6ff68967	634	*/
hexley	0:281d6ff68967	635	static void
hexley	0:281d6ff68967	636	dns_check_entry(u8_t i)
hexley	0:281d6ff68967	637	{
hexley	0:281d6ff68967	638	err_t err;
hexley	0:281d6ff68967	639	struct dns_table_entry *pEntry = &dns_table[i];
hexley	0:281d6ff68967	640
hexley	0:281d6ff68967	641	LWIP_ASSERT("array index out of bounds", i < DNS_TABLE_SIZE);
hexley	0:281d6ff68967	642
hexley	0:281d6ff68967	643	switch(pEntry->state) {
hexley	0:281d6ff68967	644
hexley	0:281d6ff68967	645	case DNS_STATE_NEW: {
hexley	0:281d6ff68967	646	/* initialize new entry */
hexley	0:281d6ff68967	647	pEntry->state = DNS_STATE_ASKING;
hexley	0:281d6ff68967	648	pEntry->numdns = 0;
hexley	0:281d6ff68967	649	pEntry->tmr = 1;
hexley	0:281d6ff68967	650	pEntry->retries = 0;
hexley	0:281d6ff68967	651
hexley	0:281d6ff68967	652	/* send DNS packet for this entry */
hexley	0:281d6ff68967	653	err = dns_send(pEntry->numdns, pEntry->name, i);
hexley	0:281d6ff68967	654	if (err != ERR_OK) {
hexley	0:281d6ff68967	655	LWIP_DEBUGF(DNS_DEBUG \| LWIP_DBG_LEVEL_WARNING,
hexley	0:281d6ff68967	656	("dns_send returned error: %d\n", err)); //FIX DG, lwip_strerr is part of lwip/api
hexley	0:281d6ff68967	657	}
hexley	0:281d6ff68967	658	break;
hexley	0:281d6ff68967	659	}
hexley	0:281d6ff68967	660
hexley	0:281d6ff68967	661	case DNS_STATE_ASKING: {
hexley	0:281d6ff68967	662	if (--pEntry->tmr == 0) {
hexley	0:281d6ff68967	663	if (++pEntry->retries == DNS_MAX_RETRIES) {
hexley	0:281d6ff68967	664	if ((pEntry->numdns+1<DNS_MAX_SERVERS) && !ip_addr_isany(&dns_servers[pEntry->numdns+1])) {
hexley	0:281d6ff68967	665	/* change of server */
hexley	0:281d6ff68967	666	pEntry->numdns++;
hexley	0:281d6ff68967	667	pEntry->tmr = 1;
hexley	0:281d6ff68967	668	pEntry->retries = 0;
hexley	0:281d6ff68967	669	break;
hexley	0:281d6ff68967	670	} else {
hexley	0:281d6ff68967	671	LWIP_DEBUGF(DNS_DEBUG, ("dns_check_entry: \"%s\": timeout\n", pEntry->name));
hexley	0:281d6ff68967	672	/* call specified callback function if provided */
hexley	0:281d6ff68967	673	if (pEntry->found)
hexley	0:281d6ff68967	674	(*pEntry->found)(pEntry->name, NULL, pEntry->arg);
hexley	0:281d6ff68967	675	/* flush this entry */
hexley	0:281d6ff68967	676	pEntry->state = DNS_STATE_UNUSED;
hexley	0:281d6ff68967	677	pEntry->found = NULL;
hexley	0:281d6ff68967	678	break;
hexley	0:281d6ff68967	679	}
hexley	0:281d6ff68967	680	}
hexley	0:281d6ff68967	681
hexley	0:281d6ff68967	682	/* wait longer for the next retry */
hexley	0:281d6ff68967	683	pEntry->tmr = pEntry->retries;
hexley	0:281d6ff68967	684
hexley	0:281d6ff68967	685	/* send DNS packet for this entry */
hexley	0:281d6ff68967	686	err = dns_send(pEntry->numdns, pEntry->name, i);
hexley	0:281d6ff68967	687	if (err != ERR_OK) {
hexley	0:281d6ff68967	688	LWIP_DEBUGF(DNS_DEBUG \| LWIP_DBG_LEVEL_WARNING,
hexley	0:281d6ff68967	689	("dns_send returned error: %d\n", err)); //FIX DG, lwip_strerr is part of lwip/api
hexley	0:281d6ff68967	690	}
hexley	0:281d6ff68967	691	}
hexley	0:281d6ff68967	692	break;
hexley	0:281d6ff68967	693	}
hexley	0:281d6ff68967	694
hexley	0:281d6ff68967	695	case DNS_STATE_DONE: {
hexley	0:281d6ff68967	696	/* if the time to live is nul */
hexley	0:281d6ff68967	697	if (--pEntry->ttl == 0) {
hexley	0:281d6ff68967	698	LWIP_DEBUGF(DNS_DEBUG, ("dns_check_entry: \"%s\": flush\n", pEntry->name));
hexley	0:281d6ff68967	699	/* flush this entry */
hexley	0:281d6ff68967	700	pEntry->state = DNS_STATE_UNUSED;
hexley	0:281d6ff68967	701	pEntry->found = NULL;
hexley	0:281d6ff68967	702	}
hexley	0:281d6ff68967	703	break;
hexley	0:281d6ff68967	704	}
hexley	0:281d6ff68967	705	case DNS_STATE_UNUSED:
hexley	0:281d6ff68967	706	/* nothing to do */
hexley	0:281d6ff68967	707	break;
hexley	0:281d6ff68967	708	default:
hexley	0:281d6ff68967	709	LWIP_ASSERT("unknown dns_table entry state:", 0);
hexley	0:281d6ff68967	710	break;
hexley	0:281d6ff68967	711	}
hexley	0:281d6ff68967	712	}
hexley	0:281d6ff68967	713
hexley	0:281d6ff68967	714	/**
hexley	0:281d6ff68967	715	* Call dns_check_entry for each entry in dns_table - check all entries.
hexley	0:281d6ff68967	716	*/
hexley	0:281d6ff68967	717	static void
hexley	0:281d6ff68967	718	dns_check_entries(void)
hexley	0:281d6ff68967	719	{
hexley	0:281d6ff68967	720	u8_t i;
hexley	0:281d6ff68967	721
hexley	0:281d6ff68967	722	for (i = 0; i < DNS_TABLE_SIZE; ++i) {
hexley	0:281d6ff68967	723	dns_check_entry(i);
hexley	0:281d6ff68967	724	}
hexley	0:281d6ff68967	725	}
hexley	0:281d6ff68967	726
hexley	0:281d6ff68967	727	/**
hexley	0:281d6ff68967	728	* Receive input function for DNS response packets arriving for the dns UDP pcb.
hexley	0:281d6ff68967	729	*
hexley	0:281d6ff68967	730	* @params see udp.h
hexley	0:281d6ff68967	731	*/
hexley	0:281d6ff68967	732	static void
hexley	0:281d6ff68967	733	dns_recv(void arg, struct udp_pcb pcb, struct pbuf p, ip_addr_t addr, u16_t port)
hexley	0:281d6ff68967	734	{
hexley	0:281d6ff68967	735	u16_t i;
hexley	0:281d6ff68967	736	char *pHostname;
hexley	0:281d6ff68967	737	struct dns_hdr *hdr;
hexley	0:281d6ff68967	738	struct dns_answer ans;
hexley	0:281d6ff68967	739	struct dns_table_entry *pEntry;
hexley	0:281d6ff68967	740	u16_t nquestions, nanswers;
hexley	0:281d6ff68967	741
hexley	0:281d6ff68967	742	LWIP_UNUSED_ARG(arg);
hexley	0:281d6ff68967	743	LWIP_UNUSED_ARG(pcb);
hexley	0:281d6ff68967	744	LWIP_UNUSED_ARG(addr);
hexley	0:281d6ff68967	745	LWIP_UNUSED_ARG(port);
hexley	0:281d6ff68967	746
hexley	0:281d6ff68967	747	/* is the dns message too big ? */
hexley	0:281d6ff68967	748	if (p->tot_len > DNS_MSG_SIZE) {
hexley	0:281d6ff68967	749	LWIP_DEBUGF(DNS_DEBUG, ("dns_recv: pbuf too big\n"));
hexley	0:281d6ff68967	750	/* free pbuf and return */
hexley	0:281d6ff68967	751	goto memerr;
hexley	0:281d6ff68967	752	}
hexley	0:281d6ff68967	753
hexley	0:281d6ff68967	754	/* is the dns message big enough ? */
hexley	0:281d6ff68967	755	if (p->tot_len < (SIZEOF_DNS_HDR + SIZEOF_DNS_QUERY + SIZEOF_DNS_ANSWER)) {
hexley	0:281d6ff68967	756	LWIP_DEBUGF(DNS_DEBUG, ("dns_recv: pbuf too small\n"));
hexley	0:281d6ff68967	757	/* free pbuf and return */
hexley	0:281d6ff68967	758	goto memerr;
hexley	0:281d6ff68967	759	}
hexley	0:281d6ff68967	760
hexley	0:281d6ff68967	761	/* copy dns payload inside static buffer for processing */
hexley	0:281d6ff68967	762	if (pbuf_copy_partial(p, dns_payload, p->tot_len, 0) == p->tot_len) {
hexley	0:281d6ff68967	763	/* The ID in the DNS header should be our entry into the name table. */
hexley	0:281d6ff68967	764	hdr = (struct dns_hdr*)dns_payload;
hexley	0:281d6ff68967	765	i = htons(hdr->id);
hexley	0:281d6ff68967	766	if (i < DNS_TABLE_SIZE) {
hexley	0:281d6ff68967	767	pEntry = &dns_table[i];
hexley	0:281d6ff68967	768	if(pEntry->state == DNS_STATE_ASKING) {
hexley	0:281d6ff68967	769	/* This entry is now completed. */
hexley	0:281d6ff68967	770	pEntry->state = DNS_STATE_DONE;
hexley	0:281d6ff68967	771	pEntry->err = hdr->flags2 & DNS_FLAG2_ERR_MASK;
hexley	0:281d6ff68967	772
hexley	0:281d6ff68967	773	/* We only care about the question(s) and the answers. The authrr
hexley	0:281d6ff68967	774	and the extrarr are simply discarded. */
hexley	0:281d6ff68967	775	nquestions = htons(hdr->numquestions);
hexley	0:281d6ff68967	776	nanswers = htons(hdr->numanswers);
hexley	0:281d6ff68967	777
hexley	0:281d6ff68967	778	/* Check for error. If so, call callback to inform. */
hexley	0:281d6ff68967	779	if (((hdr->flags1 & DNS_FLAG1_RESPONSE) == 0) \|\| (pEntry->err != 0) \|\| (nquestions != 1)) {
hexley	0:281d6ff68967	780	LWIP_DEBUGF(DNS_DEBUG, ("dns_recv: \"%s\": error in flags\n", pEntry->name));
hexley	0:281d6ff68967	781	/* call callback to indicate error, clean up memory and return */
hexley	0:281d6ff68967	782	goto responseerr;
hexley	0:281d6ff68967	783	}
hexley	0:281d6ff68967	784
hexley	0:281d6ff68967	785	#if DNS_DOES_NAME_CHECK
hexley	0:281d6ff68967	786	/* Check if the name in the "question" part match with the name in the entry. */
hexley	0:281d6ff68967	787	if (dns_compare_name((unsigned char )(pEntry->name), (unsigned char )dns_payload + SIZEOF_DNS_HDR) != 0) {
hexley	0:281d6ff68967	788	LWIP_DEBUGF(DNS_DEBUG, ("dns_recv: \"%s\": response not match to query\n", pEntry->name));
hexley	0:281d6ff68967	789	/* call callback to indicate error, clean up memory and return */
hexley	0:281d6ff68967	790	goto responseerr;
hexley	0:281d6ff68967	791	}
hexley	0:281d6ff68967	792	#endif /* DNS_DOES_NAME_CHECK */
hexley	0:281d6ff68967	793
hexley	0:281d6ff68967	794	/* Skip the name in the "question" part */
hexley	0:281d6ff68967	795	pHostname = (char ) dns_parse_name((unsigned char )dns_payload + SIZEOF_DNS_HDR) + SIZEOF_DNS_QUERY;
hexley	0:281d6ff68967	796
hexley	0:281d6ff68967	797	while (nanswers > 0) {
hexley	0:281d6ff68967	798	/* skip answer resource record's host name */
hexley	0:281d6ff68967	799	pHostname = (char ) dns_parse_name((unsigned char )pHostname);
hexley	0:281d6ff68967	800
hexley	0:281d6ff68967	801	/* Check for IP address type and Internet class. Others are discarded. */
hexley	0:281d6ff68967	802	SMEMCPY(&ans, pHostname, SIZEOF_DNS_ANSWER);
hexley	0:281d6ff68967	803	if((ans.type == PP_HTONS(DNS_RRTYPE_A)) && (ans.cls == PP_HTONS(DNS_RRCLASS_IN)) &&
hexley	0:281d6ff68967	804	(ans.len == PP_HTONS(sizeof(ip_addr_t))) ) {
hexley	0:281d6ff68967	805	/* read the answer resource record's TTL, and maximize it if needed */
hexley	0:281d6ff68967	806	pEntry->ttl = ntohl(ans.ttl);
hexley	0:281d6ff68967	807	if (pEntry->ttl > DNS_MAX_TTL) {
hexley	0:281d6ff68967	808	pEntry->ttl = DNS_MAX_TTL;
hexley	0:281d6ff68967	809	}
hexley	0:281d6ff68967	810	/* read the IP address after answer resource record's header */
hexley	0:281d6ff68967	811	SMEMCPY(&(pEntry->ipaddr), (pHostname+SIZEOF_DNS_ANSWER), sizeof(ip_addr_t));
hexley	0:281d6ff68967	812	LWIP_DEBUGF(DNS_DEBUG, ("dns_recv: \"%s\": response = ", pEntry->name));
hexley	0:281d6ff68967	813	ip_addr_debug_print(DNS_DEBUG, (&(pEntry->ipaddr)));
hexley	0:281d6ff68967	814	LWIP_DEBUGF(DNS_DEBUG, ("\n"));
hexley	0:281d6ff68967	815	/* call specified callback function if provided */
hexley	0:281d6ff68967	816	if (pEntry->found) {
hexley	0:281d6ff68967	817	(*pEntry->found)(pEntry->name, &pEntry->ipaddr, pEntry->arg);
hexley	0:281d6ff68967	818	}
hexley	0:281d6ff68967	819	/* deallocate memory and return */
hexley	0:281d6ff68967	820	goto memerr;
hexley	0:281d6ff68967	821	} else {
hexley	0:281d6ff68967	822	pHostname = pHostname + SIZEOF_DNS_ANSWER + htons(ans.len);
hexley	0:281d6ff68967	823	}
hexley	0:281d6ff68967	824	--nanswers;
hexley	0:281d6ff68967	825	}
hexley	0:281d6ff68967	826	LWIP_DEBUGF(DNS_DEBUG, ("dns_recv: \"%s\": error in response\n", pEntry->name));
hexley	0:281d6ff68967	827	/* call callback to indicate error, clean up memory and return */
hexley	0:281d6ff68967	828	goto responseerr;
hexley	0:281d6ff68967	829	}
hexley	0:281d6ff68967	830	}
hexley	0:281d6ff68967	831	}
hexley	0:281d6ff68967	832
hexley	0:281d6ff68967	833	/* deallocate memory and return */
hexley	0:281d6ff68967	834	goto memerr;
hexley	0:281d6ff68967	835
hexley	0:281d6ff68967	836	responseerr:
hexley	0:281d6ff68967	837	/* ERROR: call specified callback function with NULL as name to indicate an error */
hexley	0:281d6ff68967	838	if (pEntry->found) {
hexley	0:281d6ff68967	839	(*pEntry->found)(pEntry->name, NULL, pEntry->arg);
hexley	0:281d6ff68967	840	}
hexley	0:281d6ff68967	841	/* flush this entry */
hexley	0:281d6ff68967	842	pEntry->state = DNS_STATE_UNUSED;
hexley	0:281d6ff68967	843	pEntry->found = NULL;
hexley	0:281d6ff68967	844
hexley	0:281d6ff68967	845	memerr:
hexley	0:281d6ff68967	846	/* free pbuf */
hexley	0:281d6ff68967	847	pbuf_free(p);
hexley	0:281d6ff68967	848	return;
hexley	0:281d6ff68967	849	}
hexley	0:281d6ff68967	850
hexley	0:281d6ff68967	851	/**
hexley	0:281d6ff68967	852	* Queues a new hostname to resolve and sends out a DNS query for that hostname
hexley	0:281d6ff68967	853	*
hexley	0:281d6ff68967	854	* @param name the hostname that is to be queried
hexley	0:281d6ff68967	855	* @param found a callback founction to be called on success, failure or timeout
hexley	0:281d6ff68967	856	* @param callback_arg argument to pass to the callback function
hexley	0:281d6ff68967	857	* @return @return a err_t return code.
hexley	0:281d6ff68967	858	*/
hexley	0:281d6ff68967	859	static err_t
hexley	0:281d6ff68967	860	dns_enqueue(const char name, dns_found_callback found, void callback_arg)
hexley	0:281d6ff68967	861	{
hexley	0:281d6ff68967	862	u8_t i;
hexley	0:281d6ff68967	863	u8_t lseq, lseqi;
hexley	0:281d6ff68967	864	struct dns_table_entry *pEntry = NULL;
hexley	0:281d6ff68967	865	size_t namelen;
hexley	0:281d6ff68967	866
hexley	0:281d6ff68967	867	/* search an unused entry, or the oldest one */
hexley	0:281d6ff68967	868	lseq = lseqi = 0;
hexley	0:281d6ff68967	869	for (i = 0; i < DNS_TABLE_SIZE; ++i) {
hexley	0:281d6ff68967	870	pEntry = &dns_table[i];
hexley	0:281d6ff68967	871	/* is it an unused entry ? */
hexley	0:281d6ff68967	872	if (pEntry->state == DNS_STATE_UNUSED)
hexley	0:281d6ff68967	873	break;
hexley	0:281d6ff68967	874
hexley	0:281d6ff68967	875	/* check if this is the oldest completed entry */
hexley	0:281d6ff68967	876	if (pEntry->state == DNS_STATE_DONE) {
hexley	0:281d6ff68967	877	if ((dns_seqno - pEntry->seqno) > lseq) {
hexley	0:281d6ff68967	878	lseq = dns_seqno - pEntry->seqno;
hexley	0:281d6ff68967	879	lseqi = i;
hexley	0:281d6ff68967	880	}
hexley	0:281d6ff68967	881	}
hexley	0:281d6ff68967	882	}
hexley	0:281d6ff68967	883
hexley	0:281d6ff68967	884	/* if we don't have found an unused entry, use the oldest completed one */
hexley	0:281d6ff68967	885	if (i == DNS_TABLE_SIZE) {
hexley	0:281d6ff68967	886	if ((lseqi >= DNS_TABLE_SIZE) \|\| (dns_table[lseqi].state != DNS_STATE_DONE)) {
hexley	0:281d6ff68967	887	/* no entry can't be used now, table is full */
hexley	0:281d6ff68967	888	LWIP_DEBUGF(DNS_DEBUG, ("dns_enqueue: \"%s\": DNS entries table is full\n", name));
hexley	0:281d6ff68967	889	return ERR_MEM;
hexley	0:281d6ff68967	890	} else {
hexley	0:281d6ff68967	891	/* use the oldest completed one */
hexley	0:281d6ff68967	892	i = lseqi;
hexley	0:281d6ff68967	893	pEntry = &dns_table[i];
hexley	0:281d6ff68967	894	}
hexley	0:281d6ff68967	895	}
hexley	0:281d6ff68967	896
hexley	0:281d6ff68967	897	/* use this entry */
hexley	0:281d6ff68967	898	LWIP_DEBUGF(DNS_DEBUG, ("dns_enqueue: \"%s\": use DNS entry %"U16_F"\n", name, (u16_t)(i)));
hexley	0:281d6ff68967	899
hexley	0:281d6ff68967	900	/* fill the entry */
hexley	0:281d6ff68967	901	pEntry->state = DNS_STATE_NEW;
hexley	0:281d6ff68967	902	pEntry->seqno = dns_seqno++;
hexley	0:281d6ff68967	903	pEntry->found = found;
hexley	0:281d6ff68967	904	pEntry->arg = callback_arg;
hexley	0:281d6ff68967	905	namelen = LWIP_MIN(strlen(name), DNS_MAX_NAME_LENGTH-1);
hexley	0:281d6ff68967	906	MEMCPY(pEntry->name, name, namelen);
hexley	0:281d6ff68967	907	pEntry->name[namelen] = 0;
hexley	0:281d6ff68967	908
hexley	0:281d6ff68967	909	/* force to send query without waiting timer */
hexley	0:281d6ff68967	910	dns_check_entry(i);
hexley	0:281d6ff68967	911
hexley	0:281d6ff68967	912	/* dns query is enqueued */
hexley	0:281d6ff68967	913	return ERR_INPROGRESS;
hexley	0:281d6ff68967	914	}
hexley	0:281d6ff68967	915
hexley	0:281d6ff68967	916	/**
hexley	0:281d6ff68967	917	* Resolve a hostname (string) into an IP address.
hexley	0:281d6ff68967	918	* NON-BLOCKING callback version for use with raw API!!!
hexley	0:281d6ff68967	919	*
hexley	0:281d6ff68967	920	* Returns immediately with one of err_t return codes:
hexley	0:281d6ff68967	921	* - ERR_OK if hostname is a valid IP address string or the host
hexley	0:281d6ff68967	922	* name is already in the local names table.
hexley	0:281d6ff68967	923	* - ERR_INPROGRESS enqueue a request to be sent to the DNS server
hexley	0:281d6ff68967	924	* for resolution if no errors are present.
hexley	0:281d6ff68967	925	*
hexley	0:281d6ff68967	926	* @param hostname the hostname that is to be queried
hexley	0:281d6ff68967	927	* @param addr pointer to a ip_addr_t where to store the address if it is already
hexley	0:281d6ff68967	928	* cached in the dns_table (only valid if ERR_OK is returned!)
hexley	0:281d6ff68967	929	* @param found a callback function to be called on success, failure or timeout (only if
hexley	0:281d6ff68967	930	* ERR_INPROGRESS is returned!)
hexley	0:281d6ff68967	931	* @param callback_arg argument to pass to the callback function
hexley	0:281d6ff68967	932	* @return a err_t return code.
hexley	0:281d6ff68967	933	*/
hexley	0:281d6ff68967	934	err_t
hexley	0:281d6ff68967	935	dns_gethostbyname(const char hostname, ip_addr_t addr, dns_found_callback found,
hexley	0:281d6ff68967	936	void *callback_arg)
hexley	0:281d6ff68967	937	{
hexley	0:281d6ff68967	938	u32_t ipaddr;
hexley	0:281d6ff68967	939	/* not initialized or no valid server yet, or invalid addr pointer
hexley	0:281d6ff68967	940	* or invalid hostname or invalid hostname length */
hexley	0:281d6ff68967	941	if ((dns_pcb == NULL) \|\| (addr == NULL) \|\|
hexley	0:281d6ff68967	942	(!hostname) \|\| (!hostname[0]) \|\|
hexley	0:281d6ff68967	943	(strlen(hostname) >= DNS_MAX_NAME_LENGTH)) {
hexley	0:281d6ff68967	944	return ERR_VAL;
hexley	0:281d6ff68967	945	}
hexley	0:281d6ff68967	946
hexley	0:281d6ff68967	947	#if LWIP_HAVE_LOOPIF
hexley	0:281d6ff68967	948	if (strcmp(hostname, "localhost")==0) {
hexley	0:281d6ff68967	949	ip_addr_set_loopback(addr);
hexley	0:281d6ff68967	950	return ERR_OK;
hexley	0:281d6ff68967	951	}
hexley	0:281d6ff68967	952	#endif /* LWIP_HAVE_LOOPIF */
hexley	0:281d6ff68967	953
hexley	0:281d6ff68967	954	/* host name already in octet notation? set ip addr and return ERR_OK */
hexley	0:281d6ff68967	955	ipaddr = ipaddr_addr(hostname);
hexley	0:281d6ff68967	956	if (ipaddr == IPADDR_NONE) {
hexley	0:281d6ff68967	957	/* already have this address cached? */
hexley	0:281d6ff68967	958	ipaddr = dns_lookup(hostname);
hexley	0:281d6ff68967	959	}
hexley	0:281d6ff68967	960	if (ipaddr != IPADDR_NONE) {
hexley	0:281d6ff68967	961	ip4_addr_set_u32(addr, ipaddr);
hexley	0:281d6ff68967	962	return ERR_OK;
hexley	0:281d6ff68967	963	}
hexley	0:281d6ff68967	964
hexley	0:281d6ff68967	965	/* queue query with specified callback */
hexley	0:281d6ff68967	966	return dns_enqueue(hostname, found, callback_arg);
hexley	0:281d6ff68967	967	}
hexley	0:281d6ff68967	968
hexley	0:281d6ff68967	969	#endif /* LWIP_DNS */

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Type:	Library
Created:	19 Nov 2010
Imports:	44
Forks:	0
Commits:	1
Dependents:	0
Dependencies:	0
Followers:	1

lwip/core/dns.c@0:281d6ff68967, 2010-11-19 (annotated)

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