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lwip/core/dns.c@0:d7bd7384a37c, 2016-12-07 (annotated)

Committer:
grzemich
Date:
Wed Dec 07 23:47:50 2016 +0000
Revision:
0:d7bd7384a37c
dgd

Who changed what in which revision?

UserRevisionLine numberNew contents of line
grzemich 0:d7bd7384a37c 1 /**
grzemich 0:d7bd7384a37c 2 * @file
grzemich 0:d7bd7384a37c 3 * DNS - host name to IP address resolver.
grzemich 0:d7bd7384a37c 4 *
grzemich 0:d7bd7384a37c 5 */
grzemich 0:d7bd7384a37c 6
grzemich 0:d7bd7384a37c 7 /**
grzemich 0:d7bd7384a37c 8
grzemich 0:d7bd7384a37c 9 * This file implements a DNS host name to IP address resolver.
grzemich 0:d7bd7384a37c 10
grzemich 0:d7bd7384a37c 11 * Port to lwIP from uIP
grzemich 0:d7bd7384a37c 12 * by Jim Pettinato April 2007
grzemich 0:d7bd7384a37c 13
grzemich 0:d7bd7384a37c 14 * uIP version Copyright (c) 2002-2003, Adam Dunkels.
grzemich 0:d7bd7384a37c 15 * All rights reserved.
grzemich 0:d7bd7384a37c 16 *
grzemich 0:d7bd7384a37c 17 * Redistribution and use in source and binary forms, with or without
grzemich 0:d7bd7384a37c 18 * modification, are permitted provided that the following conditions
grzemich 0:d7bd7384a37c 19 * are met:
grzemich 0:d7bd7384a37c 20 * 1. Redistributions of source code must retain the above copyright
grzemich 0:d7bd7384a37c 21 * notice, this list of conditions and the following disclaimer.
grzemich 0:d7bd7384a37c 22 * 2. Redistributions in binary form must reproduce the above copyright
grzemich 0:d7bd7384a37c 23 * notice, this list of conditions and the following disclaimer in the
grzemich 0:d7bd7384a37c 24 * documentation and/or other materials provided with the distribution.
grzemich 0:d7bd7384a37c 25 * 3. The name of the author may not be used to endorse or promote
grzemich 0:d7bd7384a37c 26 * products derived from this software without specific prior
grzemich 0:d7bd7384a37c 27 * written permission.
grzemich 0:d7bd7384a37c 28 *
grzemich 0:d7bd7384a37c 29 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
grzemich 0:d7bd7384a37c 30 * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
grzemich 0:d7bd7384a37c 31 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
grzemich 0:d7bd7384a37c 32 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
grzemich 0:d7bd7384a37c 33 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
grzemich 0:d7bd7384a37c 34 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
grzemich 0:d7bd7384a37c 35 * GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
grzemich 0:d7bd7384a37c 36 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
grzemich 0:d7bd7384a37c 37 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
grzemich 0:d7bd7384a37c 38 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
grzemich 0:d7bd7384a37c 39 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
grzemich 0:d7bd7384a37c 40 *
grzemich 0:d7bd7384a37c 41 *
grzemich 0:d7bd7384a37c 42 * DNS.C
grzemich 0:d7bd7384a37c 43 *
grzemich 0:d7bd7384a37c 44 * The lwIP DNS resolver functions are used to lookup a host name and
grzemich 0:d7bd7384a37c 45 * map it to a numerical IP address. It maintains a list of resolved
grzemich 0:d7bd7384a37c 46 * hostnames that can be queried with the dns_lookup() function.
grzemich 0:d7bd7384a37c 47 * New hostnames can be resolved using the dns_query() function.
grzemich 0:d7bd7384a37c 48 *
grzemich 0:d7bd7384a37c 49 * The lwIP version of the resolver also adds a non-blocking version of
grzemich 0:d7bd7384a37c 50 * gethostbyname() that will work with a raw API application. This function
grzemich 0:d7bd7384a37c 51 * checks for an IP address string first and converts it if it is valid.
grzemich 0:d7bd7384a37c 52 * gethostbyname() then does a dns_lookup() to see if the name is
grzemich 0:d7bd7384a37c 53 * already in the table. If so, the IP is returned. If not, a query is
grzemich 0:d7bd7384a37c 54 * issued and the function returns with a ERR_INPROGRESS status. The app
grzemich 0:d7bd7384a37c 55 * using the dns client must then go into a waiting state.
grzemich 0:d7bd7384a37c 56 *
grzemich 0:d7bd7384a37c 57 * Once a hostname has been resolved (or found to be non-existent),
grzemich 0:d7bd7384a37c 58 * the resolver code calls a specified callback function (which
grzemich 0:d7bd7384a37c 59 * must be implemented by the module that uses the resolver).
grzemich 0:d7bd7384a37c 60 */
grzemich 0:d7bd7384a37c 61
grzemich 0:d7bd7384a37c 62 /*-----------------------------------------------------------------------------
grzemich 0:d7bd7384a37c 63 * RFC 1035 - Domain names - implementation and specification
grzemich 0:d7bd7384a37c 64 * RFC 2181 - Clarifications to the DNS Specification
grzemich 0:d7bd7384a37c 65 *----------------------------------------------------------------------------*/
grzemich 0:d7bd7384a37c 66
grzemich 0:d7bd7384a37c 67 /** @todo: define good default values (rfc compliance) */
grzemich 0:d7bd7384a37c 68 /** @todo: improve answer parsing, more checkings... */
grzemich 0:d7bd7384a37c 69 /** @todo: check RFC1035 - 7.3. Processing responses */
grzemich 0:d7bd7384a37c 70
grzemich 0:d7bd7384a37c 71 /*-----------------------------------------------------------------------------
grzemich 0:d7bd7384a37c 72 * Includes
grzemich 0:d7bd7384a37c 73 *----------------------------------------------------------------------------*/
grzemich 0:d7bd7384a37c 74
grzemich 0:d7bd7384a37c 75 #include "lwip/opt.h"
grzemich 0:d7bd7384a37c 76
grzemich 0:d7bd7384a37c 77 #if LWIP_DNS /* don't build if not configured for use in lwipopts.h */
grzemich 0:d7bd7384a37c 78
grzemich 0:d7bd7384a37c 79 #include "lwip/udp.h"
grzemich 0:d7bd7384a37c 80 #include "lwip/mem.h"
grzemich 0:d7bd7384a37c 81 #include "lwip/memp.h"
grzemich 0:d7bd7384a37c 82 #include "lwip/dns.h"
grzemich 0:d7bd7384a37c 83
grzemich 0:d7bd7384a37c 84 #include <string.h>
grzemich 0:d7bd7384a37c 85
grzemich 0:d7bd7384a37c 86 /** DNS server IP address */
grzemich 0:d7bd7384a37c 87 #ifndef DNS_SERVER_ADDRESS
grzemich 0:d7bd7384a37c 88 #define DNS_SERVER_ADDRESS(ipaddr) (ip4_addr_set_u32(ipaddr, ipaddr_addr("208.67.222.222"))) /* resolver1.opendns.com */
grzemich 0:d7bd7384a37c 89 #endif
grzemich 0:d7bd7384a37c 90
grzemich 0:d7bd7384a37c 91 /** DNS server port address */
grzemich 0:d7bd7384a37c 92 #ifndef DNS_SERVER_PORT
grzemich 0:d7bd7384a37c 93 #define DNS_SERVER_PORT 53
grzemich 0:d7bd7384a37c 94 #endif
grzemich 0:d7bd7384a37c 95
grzemich 0:d7bd7384a37c 96 /** DNS maximum number of retries when asking for a name, before "timeout". */
grzemich 0:d7bd7384a37c 97 #ifndef DNS_MAX_RETRIES
grzemich 0:d7bd7384a37c 98 #define DNS_MAX_RETRIES 4
grzemich 0:d7bd7384a37c 99 #endif
grzemich 0:d7bd7384a37c 100
grzemich 0:d7bd7384a37c 101 /** DNS resource record max. TTL (one week as default) */
grzemich 0:d7bd7384a37c 102 #ifndef DNS_MAX_TTL
grzemich 0:d7bd7384a37c 103 #define DNS_MAX_TTL 604800
grzemich 0:d7bd7384a37c 104 #endif
grzemich 0:d7bd7384a37c 105
grzemich 0:d7bd7384a37c 106 /* DNS protocol flags */
grzemich 0:d7bd7384a37c 107 #define DNS_FLAG1_RESPONSE 0x80
grzemich 0:d7bd7384a37c 108 #define DNS_FLAG1_OPCODE_STATUS 0x10
grzemich 0:d7bd7384a37c 109 #define DNS_FLAG1_OPCODE_INVERSE 0x08
grzemich 0:d7bd7384a37c 110 #define DNS_FLAG1_OPCODE_STANDARD 0x00
grzemich 0:d7bd7384a37c 111 #define DNS_FLAG1_AUTHORATIVE 0x04
grzemich 0:d7bd7384a37c 112 #define DNS_FLAG1_TRUNC 0x02
grzemich 0:d7bd7384a37c 113 #define DNS_FLAG1_RD 0x01
grzemich 0:d7bd7384a37c 114 #define DNS_FLAG2_RA 0x80
grzemich 0:d7bd7384a37c 115 #define DNS_FLAG2_ERR_MASK 0x0f
grzemich 0:d7bd7384a37c 116 #define DNS_FLAG2_ERR_NONE 0x00
grzemich 0:d7bd7384a37c 117 #define DNS_FLAG2_ERR_NAME 0x03
grzemich 0:d7bd7384a37c 118
grzemich 0:d7bd7384a37c 119 /* DNS protocol states */
grzemich 0:d7bd7384a37c 120 #define DNS_STATE_UNUSED 0
grzemich 0:d7bd7384a37c 121 #define DNS_STATE_NEW 1
grzemich 0:d7bd7384a37c 122 #define DNS_STATE_ASKING 2
grzemich 0:d7bd7384a37c 123 #define DNS_STATE_DONE 3
grzemich 0:d7bd7384a37c 124
grzemich 0:d7bd7384a37c 125 #ifdef PACK_STRUCT_USE_INCLUDES
grzemich 0:d7bd7384a37c 126 # include "arch/bpstruct.h"
grzemich 0:d7bd7384a37c 127 #endif
grzemich 0:d7bd7384a37c 128 PACK_STRUCT_BEGIN
grzemich 0:d7bd7384a37c 129 /** DNS message header */
grzemich 0:d7bd7384a37c 130 struct dns_hdr {
grzemich 0:d7bd7384a37c 131 PACK_STRUCT_FIELD(u16_t id);
grzemich 0:d7bd7384a37c 132 PACK_STRUCT_FIELD(u8_t flags1);
grzemich 0:d7bd7384a37c 133 PACK_STRUCT_FIELD(u8_t flags2);
grzemich 0:d7bd7384a37c 134 PACK_STRUCT_FIELD(u16_t numquestions);
grzemich 0:d7bd7384a37c 135 PACK_STRUCT_FIELD(u16_t numanswers);
grzemich 0:d7bd7384a37c 136 PACK_STRUCT_FIELD(u16_t numauthrr);
grzemich 0:d7bd7384a37c 137 PACK_STRUCT_FIELD(u16_t numextrarr);
grzemich 0:d7bd7384a37c 138 } PACK_STRUCT_STRUCT;
grzemich 0:d7bd7384a37c 139 PACK_STRUCT_END
grzemich 0:d7bd7384a37c 140 #ifdef PACK_STRUCT_USE_INCLUDES
grzemich 0:d7bd7384a37c 141 # include "arch/epstruct.h"
grzemich 0:d7bd7384a37c 142 #endif
grzemich 0:d7bd7384a37c 143 #define SIZEOF_DNS_HDR 12
grzemich 0:d7bd7384a37c 144
grzemich 0:d7bd7384a37c 145 /** DNS query message structure.
grzemich 0:d7bd7384a37c 146 No packing needed: only used locally on the stack. */
grzemich 0:d7bd7384a37c 147 struct dns_query {
grzemich 0:d7bd7384a37c 148 /* DNS query record starts with either a domain name or a pointer
grzemich 0:d7bd7384a37c 149 to a name already present somewhere in the packet. */
grzemich 0:d7bd7384a37c 150 u16_t type;
grzemich 0:d7bd7384a37c 151 u16_t cls;
grzemich 0:d7bd7384a37c 152 };
grzemich 0:d7bd7384a37c 153 #define SIZEOF_DNS_QUERY 4
grzemich 0:d7bd7384a37c 154
grzemich 0:d7bd7384a37c 155 /** DNS answer message structure.
grzemich 0:d7bd7384a37c 156 No packing needed: only used locally on the stack. */
grzemich 0:d7bd7384a37c 157 struct dns_answer {
grzemich 0:d7bd7384a37c 158 /* DNS answer record starts with either a domain name or a pointer
grzemich 0:d7bd7384a37c 159 to a name already present somewhere in the packet. */
grzemich 0:d7bd7384a37c 160 u16_t type;
grzemich 0:d7bd7384a37c 161 u16_t cls;
grzemich 0:d7bd7384a37c 162 u32_t ttl;
grzemich 0:d7bd7384a37c 163 u16_t len;
grzemich 0:d7bd7384a37c 164 };
grzemich 0:d7bd7384a37c 165 #define SIZEOF_DNS_ANSWER 10
grzemich 0:d7bd7384a37c 166
grzemich 0:d7bd7384a37c 167 /** DNS table entry */
grzemich 0:d7bd7384a37c 168 struct dns_table_entry {
grzemich 0:d7bd7384a37c 169 u8_t state;
grzemich 0:d7bd7384a37c 170 u8_t numdns;
grzemich 0:d7bd7384a37c 171 u8_t tmr;
grzemich 0:d7bd7384a37c 172 u8_t retries;
grzemich 0:d7bd7384a37c 173 u8_t seqno;
grzemich 0:d7bd7384a37c 174 u8_t err;
grzemich 0:d7bd7384a37c 175 u32_t ttl;
grzemich 0:d7bd7384a37c 176 char name[DNS_MAX_NAME_LENGTH];
grzemich 0:d7bd7384a37c 177 ip_addr_t ipaddr;
grzemich 0:d7bd7384a37c 178 /* pointer to callback on DNS query done */
grzemich 0:d7bd7384a37c 179 dns_found_callback found;
grzemich 0:d7bd7384a37c 180 void *arg;
grzemich 0:d7bd7384a37c 181 };
grzemich 0:d7bd7384a37c 182
grzemich 0:d7bd7384a37c 183 #if DNS_LOCAL_HOSTLIST
grzemich 0:d7bd7384a37c 184
grzemich 0:d7bd7384a37c 185 #if DNS_LOCAL_HOSTLIST_IS_DYNAMIC
grzemich 0:d7bd7384a37c 186 /** Local host-list. For hostnames in this list, no
grzemich 0:d7bd7384a37c 187 * external name resolution is performed */
grzemich 0:d7bd7384a37c 188 static struct local_hostlist_entry *local_hostlist_dynamic;
grzemich 0:d7bd7384a37c 189 #else /* DNS_LOCAL_HOSTLIST_IS_DYNAMIC */
grzemich 0:d7bd7384a37c 190
grzemich 0:d7bd7384a37c 191 /** Defining this allows the local_hostlist_static to be placed in a different
grzemich 0:d7bd7384a37c 192 * linker section (e.g. FLASH) */
grzemich 0:d7bd7384a37c 193 #ifndef DNS_LOCAL_HOSTLIST_STORAGE_PRE
grzemich 0:d7bd7384a37c 194 #define DNS_LOCAL_HOSTLIST_STORAGE_PRE static
grzemich 0:d7bd7384a37c 195 #endif /* DNS_LOCAL_HOSTLIST_STORAGE_PRE */
grzemich 0:d7bd7384a37c 196 /** Defining this allows the local_hostlist_static to be placed in a different
grzemich 0:d7bd7384a37c 197 * linker section (e.g. FLASH) */
grzemich 0:d7bd7384a37c 198 #ifndef DNS_LOCAL_HOSTLIST_STORAGE_POST
grzemich 0:d7bd7384a37c 199 #define DNS_LOCAL_HOSTLIST_STORAGE_POST
grzemich 0:d7bd7384a37c 200 #endif /* DNS_LOCAL_HOSTLIST_STORAGE_POST */
grzemich 0:d7bd7384a37c 201 DNS_LOCAL_HOSTLIST_STORAGE_PRE struct local_hostlist_entry local_hostlist_static[]
grzemich 0:d7bd7384a37c 202 DNS_LOCAL_HOSTLIST_STORAGE_POST = DNS_LOCAL_HOSTLIST_INIT;
grzemich 0:d7bd7384a37c 203
grzemich 0:d7bd7384a37c 204 #endif /* DNS_LOCAL_HOSTLIST_IS_DYNAMIC */
grzemich 0:d7bd7384a37c 205
grzemich 0:d7bd7384a37c 206 static void dns_init_local();
grzemich 0:d7bd7384a37c 207 #endif /* DNS_LOCAL_HOSTLIST */
grzemich 0:d7bd7384a37c 208
grzemich 0:d7bd7384a37c 209
grzemich 0:d7bd7384a37c 210 /* forward declarations */
grzemich 0:d7bd7384a37c 211 static void dns_recv(void *s, struct udp_pcb *pcb, struct pbuf *p, ip_addr_t *addr, u16_t port);
grzemich 0:d7bd7384a37c 212 static void dns_check_entries(void);
grzemich 0:d7bd7384a37c 213
grzemich 0:d7bd7384a37c 214 /*-----------------------------------------------------------------------------
grzemich 0:d7bd7384a37c 215 * Globales
grzemich 0:d7bd7384a37c 216 *----------------------------------------------------------------------------*/
grzemich 0:d7bd7384a37c 217
grzemich 0:d7bd7384a37c 218 /* DNS variables */
grzemich 0:d7bd7384a37c 219 static struct udp_pcb *dns_pcb;
grzemich 0:d7bd7384a37c 220 static u8_t dns_seqno;
grzemich 0:d7bd7384a37c 221 static struct dns_table_entry dns_table[DNS_TABLE_SIZE];
grzemich 0:d7bd7384a37c 222 static ip_addr_t dns_servers[DNS_MAX_SERVERS];
grzemich 0:d7bd7384a37c 223 /** Contiguous buffer for processing responses */
grzemich 0:d7bd7384a37c 224 static u8_t dns_payload_buffer[LWIP_MEM_ALIGN_BUFFER(DNS_MSG_SIZE)];
grzemich 0:d7bd7384a37c 225 static u8_t* dns_payload;
grzemich 0:d7bd7384a37c 226
grzemich 0:d7bd7384a37c 227 /**
grzemich 0:d7bd7384a37c 228 * Initialize the resolver: set up the UDP pcb and configure the default server
grzemich 0:d7bd7384a37c 229 * (DNS_SERVER_ADDRESS).
grzemich 0:d7bd7384a37c 230 */
grzemich 0:d7bd7384a37c 231 void
grzemich 0:d7bd7384a37c 232 dns_init()
grzemich 0:d7bd7384a37c 233 {
grzemich 0:d7bd7384a37c 234 ip_addr_t dnsserver;
grzemich 0:d7bd7384a37c 235
grzemich 0:d7bd7384a37c 236 dns_payload = (u8_t *)LWIP_MEM_ALIGN(dns_payload_buffer);
grzemich 0:d7bd7384a37c 237
grzemich 0:d7bd7384a37c 238 /* initialize default DNS server address */
grzemich 0:d7bd7384a37c 239 DNS_SERVER_ADDRESS(&dnsserver);
grzemich 0:d7bd7384a37c 240
grzemich 0:d7bd7384a37c 241 LWIP_DEBUGF(DNS_DEBUG, ("dns_init: initializing\n"));
grzemich 0:d7bd7384a37c 242
grzemich 0:d7bd7384a37c 243 /* if dns client not yet initialized... */
grzemich 0:d7bd7384a37c 244 if (dns_pcb == NULL) {
grzemich 0:d7bd7384a37c 245 dns_pcb = udp_new();
grzemich 0:d7bd7384a37c 246
grzemich 0:d7bd7384a37c 247 if (dns_pcb != NULL) {
grzemich 0:d7bd7384a37c 248 /* initialize DNS table not needed (initialized to zero since it is a
grzemich 0:d7bd7384a37c 249 * global variable) */
grzemich 0:d7bd7384a37c 250 LWIP_ASSERT("For implicit initialization to work, DNS_STATE_UNUSED needs to be 0",
grzemich 0:d7bd7384a37c 251 DNS_STATE_UNUSED == 0);
grzemich 0:d7bd7384a37c 252
grzemich 0:d7bd7384a37c 253 /* initialize DNS client */
grzemich 0:d7bd7384a37c 254 udp_bind(dns_pcb, IP_ADDR_ANY, 0);
grzemich 0:d7bd7384a37c 255 udp_recv(dns_pcb, dns_recv, NULL);
grzemich 0:d7bd7384a37c 256
grzemich 0:d7bd7384a37c 257 /* initialize default DNS primary server */
grzemich 0:d7bd7384a37c 258 dns_setserver(0, &dnsserver);
grzemich 0:d7bd7384a37c 259 }
grzemich 0:d7bd7384a37c 260 }
grzemich 0:d7bd7384a37c 261 #if DNS_LOCAL_HOSTLIST
grzemich 0:d7bd7384a37c 262 dns_init_local();
grzemich 0:d7bd7384a37c 263 #endif
grzemich 0:d7bd7384a37c 264 }
grzemich 0:d7bd7384a37c 265
grzemich 0:d7bd7384a37c 266 /**
grzemich 0:d7bd7384a37c 267 * Initialize one of the DNS servers.
grzemich 0:d7bd7384a37c 268 *
grzemich 0:d7bd7384a37c 269 * @param numdns the index of the DNS server to set must be < DNS_MAX_SERVERS
grzemich 0:d7bd7384a37c 270 * @param dnsserver IP address of the DNS server to set
grzemich 0:d7bd7384a37c 271 */
grzemich 0:d7bd7384a37c 272 void
grzemich 0:d7bd7384a37c 273 dns_setserver(u8_t numdns, ip_addr_t *dnsserver)
grzemich 0:d7bd7384a37c 274 {
grzemich 0:d7bd7384a37c 275 if ((numdns < DNS_MAX_SERVERS) && (dns_pcb != NULL) &&
grzemich 0:d7bd7384a37c 276 (dnsserver != NULL) && !ip_addr_isany(dnsserver)) {
grzemich 0:d7bd7384a37c 277 dns_servers[numdns] = (*dnsserver);
grzemich 0:d7bd7384a37c 278 }
grzemich 0:d7bd7384a37c 279 }
grzemich 0:d7bd7384a37c 280
grzemich 0:d7bd7384a37c 281 /**
grzemich 0:d7bd7384a37c 282 * Obtain one of the currently configured DNS server.
grzemich 0:d7bd7384a37c 283 *
grzemich 0:d7bd7384a37c 284 * @param numdns the index of the DNS server
grzemich 0:d7bd7384a37c 285 * @return IP address of the indexed DNS server or "ip_addr_any" if the DNS
grzemich 0:d7bd7384a37c 286 * server has not been configured.
grzemich 0:d7bd7384a37c 287 */
grzemich 0:d7bd7384a37c 288 ip_addr_t
grzemich 0:d7bd7384a37c 289 dns_getserver(u8_t numdns)
grzemich 0:d7bd7384a37c 290 {
grzemich 0:d7bd7384a37c 291 if (numdns < DNS_MAX_SERVERS) {
grzemich 0:d7bd7384a37c 292 return dns_servers[numdns];
grzemich 0:d7bd7384a37c 293 } else {
grzemich 0:d7bd7384a37c 294 return *IP_ADDR_ANY;
grzemich 0:d7bd7384a37c 295 }
grzemich 0:d7bd7384a37c 296 }
grzemich 0:d7bd7384a37c 297
grzemich 0:d7bd7384a37c 298 /**
grzemich 0:d7bd7384a37c 299 * The DNS resolver client timer - handle retries and timeouts and should
grzemich 0:d7bd7384a37c 300 * be called every DNS_TMR_INTERVAL milliseconds (every second by default).
grzemich 0:d7bd7384a37c 301 */
grzemich 0:d7bd7384a37c 302 void
grzemich 0:d7bd7384a37c 303 dns_tmr(void)
grzemich 0:d7bd7384a37c 304 {
grzemich 0:d7bd7384a37c 305 if (dns_pcb != NULL) {
grzemich 0:d7bd7384a37c 306 LWIP_DEBUGF(DNS_DEBUG, ("dns_tmr: dns_check_entries\n"));
grzemich 0:d7bd7384a37c 307 dns_check_entries();
grzemich 0:d7bd7384a37c 308 }
grzemich 0:d7bd7384a37c 309 }
grzemich 0:d7bd7384a37c 310
grzemich 0:d7bd7384a37c 311 #if DNS_LOCAL_HOSTLIST
grzemich 0:d7bd7384a37c 312 static void
grzemich 0:d7bd7384a37c 313 dns_init_local()
grzemich 0:d7bd7384a37c 314 {
grzemich 0:d7bd7384a37c 315 #if DNS_LOCAL_HOSTLIST_IS_DYNAMIC && defined(DNS_LOCAL_HOSTLIST_INIT)
grzemich 0:d7bd7384a37c 316 int i;
grzemich 0:d7bd7384a37c 317 struct local_hostlist_entry *entry;
grzemich 0:d7bd7384a37c 318 /* Dynamic: copy entries from DNS_LOCAL_HOSTLIST_INIT to list */
grzemich 0:d7bd7384a37c 319 struct local_hostlist_entry local_hostlist_init[] = DNS_LOCAL_HOSTLIST_INIT;
grzemich 0:d7bd7384a37c 320 size_t namelen;
grzemich 0:d7bd7384a37c 321 for (i = 0; i < sizeof(local_hostlist_init) / sizeof(struct local_hostlist_entry); i++) {
grzemich 0:d7bd7384a37c 322 struct local_hostlist_entry *init_entry = &local_hostlist_init[i];
grzemich 0:d7bd7384a37c 323 LWIP_ASSERT("invalid host name (NULL)", init_entry->name != NULL);
grzemich 0:d7bd7384a37c 324 namelen = strlen(init_entry->name);
grzemich 0:d7bd7384a37c 325 LWIP_ASSERT("namelen <= DNS_LOCAL_HOSTLIST_MAX_NAMELEN", namelen <= DNS_LOCAL_HOSTLIST_MAX_NAMELEN);
grzemich 0:d7bd7384a37c 326 entry = (struct local_hostlist_entry *)memp_malloc(MEMP_LOCALHOSTLIST);
grzemich 0:d7bd7384a37c 327 LWIP_ASSERT("mem-error in dns_init_local", entry != NULL);
grzemich 0:d7bd7384a37c 328 if (entry != NULL) {
grzemich 0:d7bd7384a37c 329 entry->name = (char*)entry + sizeof(struct local_hostlist_entry);
grzemich 0:d7bd7384a37c 330 MEMCPY((char*)entry->name, init_entry->name, namelen);
grzemich 0:d7bd7384a37c 331 ((char*)entry->name)[namelen] = 0;
grzemich 0:d7bd7384a37c 332 entry->addr = init_entry->addr;
grzemich 0:d7bd7384a37c 333 entry->next = local_hostlist_dynamic;
grzemich 0:d7bd7384a37c 334 local_hostlist_dynamic = entry;
grzemich 0:d7bd7384a37c 335 }
grzemich 0:d7bd7384a37c 336 }
grzemich 0:d7bd7384a37c 337 #endif /* DNS_LOCAL_HOSTLIST_IS_DYNAMIC && defined(DNS_LOCAL_HOSTLIST_INIT) */
grzemich 0:d7bd7384a37c 338 }
grzemich 0:d7bd7384a37c 339
grzemich 0:d7bd7384a37c 340 /**
grzemich 0:d7bd7384a37c 341 * Scans the local host-list for a hostname.
grzemich 0:d7bd7384a37c 342 *
grzemich 0:d7bd7384a37c 343 * @param hostname Hostname to look for in the local host-list
grzemich 0:d7bd7384a37c 344 * @return The first IP address for the hostname in the local host-list or
grzemich 0:d7bd7384a37c 345 * IPADDR_NONE if not found.
grzemich 0:d7bd7384a37c 346 */
grzemich 0:d7bd7384a37c 347 static u32_t
grzemich 0:d7bd7384a37c 348 dns_lookup_local(const char *hostname)
grzemich 0:d7bd7384a37c 349 {
grzemich 0:d7bd7384a37c 350 #if DNS_LOCAL_HOSTLIST_IS_DYNAMIC
grzemich 0:d7bd7384a37c 351 struct local_hostlist_entry *entry = local_hostlist_dynamic;
grzemich 0:d7bd7384a37c 352 while(entry != NULL) {
grzemich 0:d7bd7384a37c 353 if(strcmp(entry->name, hostname) == 0) {
grzemich 0:d7bd7384a37c 354 return ip4_addr_get_u32(&entry->addr);
grzemich 0:d7bd7384a37c 355 }
grzemich 0:d7bd7384a37c 356 entry = entry->next;
grzemich 0:d7bd7384a37c 357 }
grzemich 0:d7bd7384a37c 358 #else /* DNS_LOCAL_HOSTLIST_IS_DYNAMIC */
grzemich 0:d7bd7384a37c 359 int i;
grzemich 0:d7bd7384a37c 360 for (i = 0; i < sizeof(local_hostlist_static) / sizeof(struct local_hostlist_entry); i++) {
grzemich 0:d7bd7384a37c 361 if(strcmp(local_hostlist_static[i].name, hostname) == 0) {
grzemich 0:d7bd7384a37c 362 return ip4_addr_get_u32(&local_hostlist_static[i].addr);
grzemich 0:d7bd7384a37c 363 }
grzemich 0:d7bd7384a37c 364 }
grzemich 0:d7bd7384a37c 365 #endif /* DNS_LOCAL_HOSTLIST_IS_DYNAMIC */
grzemich 0:d7bd7384a37c 366 return IPADDR_NONE;
grzemich 0:d7bd7384a37c 367 }
grzemich 0:d7bd7384a37c 368
grzemich 0:d7bd7384a37c 369 #if DNS_LOCAL_HOSTLIST_IS_DYNAMIC
grzemich 0:d7bd7384a37c 370 /** Remove all entries from the local host-list for a specific hostname
grzemich 0:d7bd7384a37c 371 * and/or IP addess
grzemich 0:d7bd7384a37c 372 *
grzemich 0:d7bd7384a37c 373 * @param hostname hostname for which entries shall be removed from the local
grzemich 0:d7bd7384a37c 374 * host-list
grzemich 0:d7bd7384a37c 375 * @param addr address for which entries shall be removed from the local host-list
grzemich 0:d7bd7384a37c 376 * @return the number of removed entries
grzemich 0:d7bd7384a37c 377 */
grzemich 0:d7bd7384a37c 378 int
grzemich 0:d7bd7384a37c 379 dns_local_removehost(const char *hostname, const ip_addr_t *addr)
grzemich 0:d7bd7384a37c 380 {
grzemich 0:d7bd7384a37c 381 int removed = 0;
grzemich 0:d7bd7384a37c 382 struct local_hostlist_entry *entry = local_hostlist_dynamic;
grzemich 0:d7bd7384a37c 383 struct local_hostlist_entry *last_entry = NULL;
grzemich 0:d7bd7384a37c 384 while (entry != NULL) {
grzemich 0:d7bd7384a37c 385 if (((hostname == NULL) || !strcmp(entry->name, hostname)) &&
grzemich 0:d7bd7384a37c 386 ((addr == NULL) || ip_addr_cmp(&entry->addr, addr))) {
grzemich 0:d7bd7384a37c 387 struct local_hostlist_entry *free_entry;
grzemich 0:d7bd7384a37c 388 if (last_entry != NULL) {
grzemich 0:d7bd7384a37c 389 last_entry->next = entry->next;
grzemich 0:d7bd7384a37c 390 } else {
grzemich 0:d7bd7384a37c 391 local_hostlist_dynamic = entry->next;
grzemich 0:d7bd7384a37c 392 }
grzemich 0:d7bd7384a37c 393 free_entry = entry;
grzemich 0:d7bd7384a37c 394 entry = entry->next;
grzemich 0:d7bd7384a37c 395 memp_free(MEMP_LOCALHOSTLIST, free_entry);
grzemich 0:d7bd7384a37c 396 removed++;
grzemich 0:d7bd7384a37c 397 } else {
grzemich 0:d7bd7384a37c 398 last_entry = entry;
grzemich 0:d7bd7384a37c 399 entry = entry->next;
grzemich 0:d7bd7384a37c 400 }
grzemich 0:d7bd7384a37c 401 }
grzemich 0:d7bd7384a37c 402 return removed;
grzemich 0:d7bd7384a37c 403 }
grzemich 0:d7bd7384a37c 404
grzemich 0:d7bd7384a37c 405 /**
grzemich 0:d7bd7384a37c 406 * Add a hostname/IP address pair to the local host-list.
grzemich 0:d7bd7384a37c 407 * Duplicates are not checked.
grzemich 0:d7bd7384a37c 408 *
grzemich 0:d7bd7384a37c 409 * @param hostname hostname of the new entry
grzemich 0:d7bd7384a37c 410 * @param addr IP address of the new entry
grzemich 0:d7bd7384a37c 411 * @return ERR_OK if succeeded or ERR_MEM on memory error
grzemich 0:d7bd7384a37c 412 */
grzemich 0:d7bd7384a37c 413 err_t
grzemich 0:d7bd7384a37c 414 dns_local_addhost(const char *hostname, const ip_addr_t *addr)
grzemich 0:d7bd7384a37c 415 {
grzemich 0:d7bd7384a37c 416 struct local_hostlist_entry *entry;
grzemich 0:d7bd7384a37c 417 size_t namelen;
grzemich 0:d7bd7384a37c 418 LWIP_ASSERT("invalid host name (NULL)", hostname != NULL);
grzemich 0:d7bd7384a37c 419 namelen = strlen(hostname);
grzemich 0:d7bd7384a37c 420 LWIP_ASSERT("namelen <= DNS_LOCAL_HOSTLIST_MAX_NAMELEN", namelen <= DNS_LOCAL_HOSTLIST_MAX_NAMELEN);
grzemich 0:d7bd7384a37c 421 entry = (struct local_hostlist_entry *)memp_malloc(MEMP_LOCALHOSTLIST);
grzemich 0:d7bd7384a37c 422 if (entry == NULL) {
grzemich 0:d7bd7384a37c 423 return ERR_MEM;
grzemich 0:d7bd7384a37c 424 }
grzemich 0:d7bd7384a37c 425 entry->name = (char*)entry + sizeof(struct local_hostlist_entry);
grzemich 0:d7bd7384a37c 426 MEMCPY((char*)entry->name, hostname, namelen);
grzemich 0:d7bd7384a37c 427 ((char*)entry->name)[namelen] = 0;
grzemich 0:d7bd7384a37c 428 ip_addr_copy(entry->addr, *addr);
grzemich 0:d7bd7384a37c 429 entry->next = local_hostlist_dynamic;
grzemich 0:d7bd7384a37c 430 local_hostlist_dynamic = entry;
grzemich 0:d7bd7384a37c 431 return ERR_OK;
grzemich 0:d7bd7384a37c 432 }
grzemich 0:d7bd7384a37c 433 #endif /* DNS_LOCAL_HOSTLIST_IS_DYNAMIC*/
grzemich 0:d7bd7384a37c 434 #endif /* DNS_LOCAL_HOSTLIST */
grzemich 0:d7bd7384a37c 435
grzemich 0:d7bd7384a37c 436 /**
grzemich 0:d7bd7384a37c 437 * Look up a hostname in the array of known hostnames.
grzemich 0:d7bd7384a37c 438 *
grzemich 0:d7bd7384a37c 439 * @note This function only looks in the internal array of known
grzemich 0:d7bd7384a37c 440 * hostnames, it does not send out a query for the hostname if none
grzemich 0:d7bd7384a37c 441 * was found. The function dns_enqueue() can be used to send a query
grzemich 0:d7bd7384a37c 442 * for a hostname.
grzemich 0:d7bd7384a37c 443 *
grzemich 0:d7bd7384a37c 444 * @param name the hostname to look up
grzemich 0:d7bd7384a37c 445 * @return the hostname's IP address, as u32_t (instead of ip_addr_t to
grzemich 0:d7bd7384a37c 446 * better check for failure: != IPADDR_NONE) or IPADDR_NONE if the hostname
grzemich 0:d7bd7384a37c 447 * was not found in the cached dns_table.
grzemich 0:d7bd7384a37c 448 */
grzemich 0:d7bd7384a37c 449 static u32_t
grzemich 0:d7bd7384a37c 450 dns_lookup(const char *name)
grzemich 0:d7bd7384a37c 451 {
grzemich 0:d7bd7384a37c 452 u8_t i;
grzemich 0:d7bd7384a37c 453 #if DNS_LOCAL_HOSTLIST || defined(DNS_LOOKUP_LOCAL_EXTERN)
grzemich 0:d7bd7384a37c 454 u32_t addr;
grzemich 0:d7bd7384a37c 455 #endif /* DNS_LOCAL_HOSTLIST || defined(DNS_LOOKUP_LOCAL_EXTERN) */
grzemich 0:d7bd7384a37c 456 #if DNS_LOCAL_HOSTLIST
grzemich 0:d7bd7384a37c 457 if ((addr = dns_lookup_local(name)) != IPADDR_NONE) {
grzemich 0:d7bd7384a37c 458 return addr;
grzemich 0:d7bd7384a37c 459 }
grzemich 0:d7bd7384a37c 460 #endif /* DNS_LOCAL_HOSTLIST */
grzemich 0:d7bd7384a37c 461 #ifdef DNS_LOOKUP_LOCAL_EXTERN
grzemich 0:d7bd7384a37c 462 if((addr = DNS_LOOKUP_LOCAL_EXTERN(name)) != IPADDR_NONE) {
grzemich 0:d7bd7384a37c 463 return addr;
grzemich 0:d7bd7384a37c 464 }
grzemich 0:d7bd7384a37c 465 #endif /* DNS_LOOKUP_LOCAL_EXTERN */
grzemich 0:d7bd7384a37c 466
grzemich 0:d7bd7384a37c 467 /* Walk through name list, return entry if found. If not, return NULL. */
grzemich 0:d7bd7384a37c 468 for (i = 0; i < DNS_TABLE_SIZE; ++i) {
grzemich 0:d7bd7384a37c 469 if ((dns_table[i].state == DNS_STATE_DONE) &&
grzemich 0:d7bd7384a37c 470 (strcmp(name, dns_table[i].name) == 0)) {
grzemich 0:d7bd7384a37c 471 LWIP_DEBUGF(DNS_DEBUG, ("dns_lookup: \"%s\": found = ", name));
grzemich 0:d7bd7384a37c 472 ip_addr_debug_print(DNS_DEBUG, &(dns_table[i].ipaddr));
grzemich 0:d7bd7384a37c 473 LWIP_DEBUGF(DNS_DEBUG, ("\n"));
grzemich 0:d7bd7384a37c 474 return ip4_addr_get_u32(&dns_table[i].ipaddr);
grzemich 0:d7bd7384a37c 475 }
grzemich 0:d7bd7384a37c 476 }
grzemich 0:d7bd7384a37c 477
grzemich 0:d7bd7384a37c 478 return IPADDR_NONE;
grzemich 0:d7bd7384a37c 479 }
grzemich 0:d7bd7384a37c 480
grzemich 0:d7bd7384a37c 481 #if DNS_DOES_NAME_CHECK
grzemich 0:d7bd7384a37c 482 /**
grzemich 0:d7bd7384a37c 483 * Compare the "dotted" name "query" with the encoded name "response"
grzemich 0:d7bd7384a37c 484 * to make sure an answer from the DNS server matches the current dns_table
grzemich 0:d7bd7384a37c 485 * entry (otherwise, answers might arrive late for hostname not on the list
grzemich 0:d7bd7384a37c 486 * any more).
grzemich 0:d7bd7384a37c 487 *
grzemich 0:d7bd7384a37c 488 * @param query hostname (not encoded) from the dns_table
grzemich 0:d7bd7384a37c 489 * @param response encoded hostname in the DNS response
grzemich 0:d7bd7384a37c 490 * @return 0: names equal; 1: names differ
grzemich 0:d7bd7384a37c 491 */
grzemich 0:d7bd7384a37c 492 static u8_t
grzemich 0:d7bd7384a37c 493 dns_compare_name(unsigned char *query, unsigned char *response)
grzemich 0:d7bd7384a37c 494 {
grzemich 0:d7bd7384a37c 495 unsigned char n;
grzemich 0:d7bd7384a37c 496
grzemich 0:d7bd7384a37c 497 do {
grzemich 0:d7bd7384a37c 498 n = *response++;
grzemich 0:d7bd7384a37c 499 /** @see RFC 1035 - 4.1.4. Message compression */
grzemich 0:d7bd7384a37c 500 if ((n & 0xc0) == 0xc0) {
grzemich 0:d7bd7384a37c 501 /* Compressed name */
grzemich 0:d7bd7384a37c 502 break;
grzemich 0:d7bd7384a37c 503 } else {
grzemich 0:d7bd7384a37c 504 /* Not compressed name */
grzemich 0:d7bd7384a37c 505 while (n > 0) {
grzemich 0:d7bd7384a37c 506 if ((*query) != (*response)) {
grzemich 0:d7bd7384a37c 507 return 1;
grzemich 0:d7bd7384a37c 508 }
grzemich 0:d7bd7384a37c 509 ++response;
grzemich 0:d7bd7384a37c 510 ++query;
grzemich 0:d7bd7384a37c 511 --n;
grzemich 0:d7bd7384a37c 512 };
grzemich 0:d7bd7384a37c 513 ++query;
grzemich 0:d7bd7384a37c 514 }
grzemich 0:d7bd7384a37c 515 } while (*response != 0);
grzemich 0:d7bd7384a37c 516
grzemich 0:d7bd7384a37c 517 return 0;
grzemich 0:d7bd7384a37c 518 }
grzemich 0:d7bd7384a37c 519 #endif /* DNS_DOES_NAME_CHECK */
grzemich 0:d7bd7384a37c 520
grzemich 0:d7bd7384a37c 521 /**
grzemich 0:d7bd7384a37c 522 * Walk through a compact encoded DNS name and return the end of the name.
grzemich 0:d7bd7384a37c 523 *
grzemich 0:d7bd7384a37c 524 * @param query encoded DNS name in the DNS server response
grzemich 0:d7bd7384a37c 525 * @return end of the name
grzemich 0:d7bd7384a37c 526 */
grzemich 0:d7bd7384a37c 527 static unsigned char *
grzemich 0:d7bd7384a37c 528 dns_parse_name(unsigned char *query)
grzemich 0:d7bd7384a37c 529 {
grzemich 0:d7bd7384a37c 530 unsigned char n;
grzemich 0:d7bd7384a37c 531
grzemich 0:d7bd7384a37c 532 do {
grzemich 0:d7bd7384a37c 533 n = *query++;
grzemich 0:d7bd7384a37c 534 /** @see RFC 1035 - 4.1.4. Message compression */
grzemich 0:d7bd7384a37c 535 if ((n & 0xc0) == 0xc0) {
grzemich 0:d7bd7384a37c 536 /* Compressed name */
grzemich 0:d7bd7384a37c 537 break;
grzemich 0:d7bd7384a37c 538 } else {
grzemich 0:d7bd7384a37c 539 /* Not compressed name */
grzemich 0:d7bd7384a37c 540 while (n > 0) {
grzemich 0:d7bd7384a37c 541 ++query;
grzemich 0:d7bd7384a37c 542 --n;
grzemich 0:d7bd7384a37c 543 };
grzemich 0:d7bd7384a37c 544 }
grzemich 0:d7bd7384a37c 545 } while (*query != 0);
grzemich 0:d7bd7384a37c 546
grzemich 0:d7bd7384a37c 547 return query + 1;
grzemich 0:d7bd7384a37c 548 }
grzemich 0:d7bd7384a37c 549
grzemich 0:d7bd7384a37c 550 /**
grzemich 0:d7bd7384a37c 551 * Send a DNS query packet.
grzemich 0:d7bd7384a37c 552 *
grzemich 0:d7bd7384a37c 553 * @param numdns index of the DNS server in the dns_servers table
grzemich 0:d7bd7384a37c 554 * @param name hostname to query
grzemich 0:d7bd7384a37c 555 * @param id index of the hostname in dns_table, used as transaction ID in the
grzemich 0:d7bd7384a37c 556 * DNS query packet
grzemich 0:d7bd7384a37c 557 * @return ERR_OK if packet is sent; an err_t indicating the problem otherwise
grzemich 0:d7bd7384a37c 558 */
grzemich 0:d7bd7384a37c 559 static err_t
grzemich 0:d7bd7384a37c 560 dns_send(u8_t numdns, const char* name, u8_t id)
grzemich 0:d7bd7384a37c 561 {
grzemich 0:d7bd7384a37c 562 err_t err;
grzemich 0:d7bd7384a37c 563 struct dns_hdr *hdr;
grzemich 0:d7bd7384a37c 564 struct dns_query qry;
grzemich 0:d7bd7384a37c 565 struct pbuf *p;
grzemich 0:d7bd7384a37c 566 char *query, *nptr;
grzemich 0:d7bd7384a37c 567 const char *pHostname;
grzemich 0:d7bd7384a37c 568 u8_t n;
grzemich 0:d7bd7384a37c 569
grzemich 0:d7bd7384a37c 570 LWIP_DEBUGF(DNS_DEBUG, ("dns_send: dns_servers[%"U16_F"] \"%s\": request\n",
grzemich 0:d7bd7384a37c 571 (u16_t)(numdns), name));
grzemich 0:d7bd7384a37c 572 LWIP_ASSERT("dns server out of array", numdns < DNS_MAX_SERVERS);
grzemich 0:d7bd7384a37c 573 LWIP_ASSERT("dns server has no IP address set", !ip_addr_isany(&dns_servers[numdns]));
grzemich 0:d7bd7384a37c 574
grzemich 0:d7bd7384a37c 575 /* if here, we have either a new query or a retry on a previous query to process */
grzemich 0:d7bd7384a37c 576 p = pbuf_alloc(PBUF_TRANSPORT, SIZEOF_DNS_HDR + DNS_MAX_NAME_LENGTH +
grzemich 0:d7bd7384a37c 577 SIZEOF_DNS_QUERY, PBUF_RAM);
grzemich 0:d7bd7384a37c 578 if (p != NULL) {
grzemich 0:d7bd7384a37c 579 LWIP_ASSERT("pbuf must be in one piece", p->next == NULL);
grzemich 0:d7bd7384a37c 580 /* fill dns header */
grzemich 0:d7bd7384a37c 581 hdr = (struct dns_hdr*)p->payload;
grzemich 0:d7bd7384a37c 582 memset(hdr, 0, SIZEOF_DNS_HDR);
grzemich 0:d7bd7384a37c 583 hdr->id = htons(id);
grzemich 0:d7bd7384a37c 584 hdr->flags1 = DNS_FLAG1_RD;
grzemich 0:d7bd7384a37c 585 hdr->numquestions = PP_HTONS(1);
grzemich 0:d7bd7384a37c 586 query = (char*)hdr + SIZEOF_DNS_HDR;
grzemich 0:d7bd7384a37c 587 pHostname = name;
grzemich 0:d7bd7384a37c 588 --pHostname;
grzemich 0:d7bd7384a37c 589
grzemich 0:d7bd7384a37c 590 /* convert hostname into suitable query format. */
grzemich 0:d7bd7384a37c 591 do {
grzemich 0:d7bd7384a37c 592 ++pHostname;
grzemich 0:d7bd7384a37c 593 nptr = query;
grzemich 0:d7bd7384a37c 594 ++query;
grzemich 0:d7bd7384a37c 595 for(n = 0; *pHostname != '.' && *pHostname != 0; ++pHostname) {
grzemich 0:d7bd7384a37c 596 *query = *pHostname;
grzemich 0:d7bd7384a37c 597 ++query;
grzemich 0:d7bd7384a37c 598 ++n;
grzemich 0:d7bd7384a37c 599 }
grzemich 0:d7bd7384a37c 600 *nptr = n;
grzemich 0:d7bd7384a37c 601 } while(*pHostname != 0);
grzemich 0:d7bd7384a37c 602 *query++='\0';
grzemich 0:d7bd7384a37c 603
grzemich 0:d7bd7384a37c 604 /* fill dns query */
grzemich 0:d7bd7384a37c 605 qry.type = PP_HTONS(DNS_RRTYPE_A);
grzemich 0:d7bd7384a37c 606 qry.cls = PP_HTONS(DNS_RRCLASS_IN);
grzemich 0:d7bd7384a37c 607 SMEMCPY(query, &qry, SIZEOF_DNS_QUERY);
grzemich 0:d7bd7384a37c 608
grzemich 0:d7bd7384a37c 609 /* resize pbuf to the exact dns query */
grzemich 0:d7bd7384a37c 610 pbuf_realloc(p, (u16_t)((query + SIZEOF_DNS_QUERY) - ((char*)(p->payload))));
grzemich 0:d7bd7384a37c 611
grzemich 0:d7bd7384a37c 612 /* connect to the server for faster receiving */
grzemich 0:d7bd7384a37c 613 udp_connect(dns_pcb, &dns_servers[numdns], DNS_SERVER_PORT);
grzemich 0:d7bd7384a37c 614 /* send dns packet */
grzemich 0:d7bd7384a37c 615 err = udp_sendto(dns_pcb, p, &dns_servers[numdns], DNS_SERVER_PORT);
grzemich 0:d7bd7384a37c 616
grzemich 0:d7bd7384a37c 617 /* free pbuf */
grzemich 0:d7bd7384a37c 618 pbuf_free(p);
grzemich 0:d7bd7384a37c 619 } else {
grzemich 0:d7bd7384a37c 620 err = ERR_MEM;
grzemich 0:d7bd7384a37c 621 }
grzemich 0:d7bd7384a37c 622
grzemich 0:d7bd7384a37c 623 return err;
grzemich 0:d7bd7384a37c 624 }
grzemich 0:d7bd7384a37c 625
grzemich 0:d7bd7384a37c 626 /**
grzemich 0:d7bd7384a37c 627 * dns_check_entry() - see if pEntry has not yet been queried and, if so, sends out a query.
grzemich 0:d7bd7384a37c 628 * Check an entry in the dns_table:
grzemich 0:d7bd7384a37c 629 * - send out query for new entries
grzemich 0:d7bd7384a37c 630 * - retry old pending entries on timeout (also with different servers)
grzemich 0:d7bd7384a37c 631 * - remove completed entries from the table if their TTL has expired
grzemich 0:d7bd7384a37c 632 *
grzemich 0:d7bd7384a37c 633 * @param i index of the dns_table entry to check
grzemich 0:d7bd7384a37c 634 */
grzemich 0:d7bd7384a37c 635 static void
grzemich 0:d7bd7384a37c 636 dns_check_entry(u8_t i)
grzemich 0:d7bd7384a37c 637 {
grzemich 0:d7bd7384a37c 638 err_t err;
grzemich 0:d7bd7384a37c 639 struct dns_table_entry *pEntry = &dns_table[i];
grzemich 0:d7bd7384a37c 640
grzemich 0:d7bd7384a37c 641 LWIP_ASSERT("array index out of bounds", i < DNS_TABLE_SIZE);
grzemich 0:d7bd7384a37c 642
grzemich 0:d7bd7384a37c 643 switch(pEntry->state) {
grzemich 0:d7bd7384a37c 644
grzemich 0:d7bd7384a37c 645 case DNS_STATE_NEW: {
grzemich 0:d7bd7384a37c 646 /* initialize new entry */
grzemich 0:d7bd7384a37c 647 pEntry->state = DNS_STATE_ASKING;
grzemich 0:d7bd7384a37c 648 pEntry->numdns = 0;
grzemich 0:d7bd7384a37c 649 pEntry->tmr = 1;
grzemich 0:d7bd7384a37c 650 pEntry->retries = 0;
grzemich 0:d7bd7384a37c 651
grzemich 0:d7bd7384a37c 652 /* send DNS packet for this entry */
grzemich 0:d7bd7384a37c 653 err = dns_send(pEntry->numdns, pEntry->name, i);
grzemich 0:d7bd7384a37c 654 if (err != ERR_OK) {
grzemich 0:d7bd7384a37c 655 LWIP_DEBUGF(DNS_DEBUG | LWIP_DBG_LEVEL_WARNING,
grzemich 0:d7bd7384a37c 656 ("dns_send returned error: %s\n", lwip_strerr(err)));
grzemich 0:d7bd7384a37c 657 }
grzemich 0:d7bd7384a37c 658 break;
grzemich 0:d7bd7384a37c 659 }
grzemich 0:d7bd7384a37c 660
grzemich 0:d7bd7384a37c 661 case DNS_STATE_ASKING: {
grzemich 0:d7bd7384a37c 662 if (--pEntry->tmr == 0) {
grzemich 0:d7bd7384a37c 663 if (++pEntry->retries == DNS_MAX_RETRIES) {
grzemich 0:d7bd7384a37c 664 if ((pEntry->numdns+1<DNS_MAX_SERVERS) && !ip_addr_isany(&dns_servers[pEntry->numdns+1])) {
grzemich 0:d7bd7384a37c 665 /* change of server */
grzemich 0:d7bd7384a37c 666 pEntry->numdns++;
grzemich 0:d7bd7384a37c 667 pEntry->tmr = 1;
grzemich 0:d7bd7384a37c 668 pEntry->retries = 0;
grzemich 0:d7bd7384a37c 669 break;
grzemich 0:d7bd7384a37c 670 } else {
grzemich 0:d7bd7384a37c 671 LWIP_DEBUGF(DNS_DEBUG, ("dns_check_entry: \"%s\": timeout\n", pEntry->name));
grzemich 0:d7bd7384a37c 672 /* call specified callback function if provided */
grzemich 0:d7bd7384a37c 673 if (pEntry->found)
grzemich 0:d7bd7384a37c 674 (*pEntry->found)(pEntry->name, NULL, pEntry->arg);
grzemich 0:d7bd7384a37c 675 /* flush this entry */
grzemich 0:d7bd7384a37c 676 pEntry->state = DNS_STATE_UNUSED;
grzemich 0:d7bd7384a37c 677 pEntry->found = NULL;
grzemich 0:d7bd7384a37c 678 break;
grzemich 0:d7bd7384a37c 679 }
grzemich 0:d7bd7384a37c 680 }
grzemich 0:d7bd7384a37c 681
grzemich 0:d7bd7384a37c 682 /* wait longer for the next retry */
grzemich 0:d7bd7384a37c 683 pEntry->tmr = pEntry->retries;
grzemich 0:d7bd7384a37c 684
grzemich 0:d7bd7384a37c 685 /* send DNS packet for this entry */
grzemich 0:d7bd7384a37c 686 err = dns_send(pEntry->numdns, pEntry->name, i);
grzemich 0:d7bd7384a37c 687 if (err != ERR_OK) {
grzemich 0:d7bd7384a37c 688 LWIP_DEBUGF(DNS_DEBUG | LWIP_DBG_LEVEL_WARNING,
grzemich 0:d7bd7384a37c 689 ("dns_send returned error: %s\n", lwip_strerr(err)));
grzemich 0:d7bd7384a37c 690 }
grzemich 0:d7bd7384a37c 691 }
grzemich 0:d7bd7384a37c 692 break;
grzemich 0:d7bd7384a37c 693 }
grzemich 0:d7bd7384a37c 694
grzemich 0:d7bd7384a37c 695 case DNS_STATE_DONE: {
grzemich 0:d7bd7384a37c 696 /* if the time to live is nul */
grzemich 0:d7bd7384a37c 697 if (--pEntry->ttl == 0) {
grzemich 0:d7bd7384a37c 698 LWIP_DEBUGF(DNS_DEBUG, ("dns_check_entry: \"%s\": flush\n", pEntry->name));
grzemich 0:d7bd7384a37c 699 /* flush this entry */
grzemich 0:d7bd7384a37c 700 pEntry->state = DNS_STATE_UNUSED;
grzemich 0:d7bd7384a37c 701 pEntry->found = NULL;
grzemich 0:d7bd7384a37c 702 }
grzemich 0:d7bd7384a37c 703 break;
grzemich 0:d7bd7384a37c 704 }
grzemich 0:d7bd7384a37c 705 case DNS_STATE_UNUSED:
grzemich 0:d7bd7384a37c 706 /* nothing to do */
grzemich 0:d7bd7384a37c 707 break;
grzemich 0:d7bd7384a37c 708 default:
grzemich 0:d7bd7384a37c 709 LWIP_ASSERT("unknown dns_table entry state:", 0);
grzemich 0:d7bd7384a37c 710 break;
grzemich 0:d7bd7384a37c 711 }
grzemich 0:d7bd7384a37c 712 }
grzemich 0:d7bd7384a37c 713
grzemich 0:d7bd7384a37c 714 /**
grzemich 0:d7bd7384a37c 715 * Call dns_check_entry for each entry in dns_table - check all entries.
grzemich 0:d7bd7384a37c 716 */
grzemich 0:d7bd7384a37c 717 static void
grzemich 0:d7bd7384a37c 718 dns_check_entries(void)
grzemich 0:d7bd7384a37c 719 {
grzemich 0:d7bd7384a37c 720 u8_t i;
grzemich 0:d7bd7384a37c 721
grzemich 0:d7bd7384a37c 722 for (i = 0; i < DNS_TABLE_SIZE; ++i) {
grzemich 0:d7bd7384a37c 723 dns_check_entry(i);
grzemich 0:d7bd7384a37c 724 }
grzemich 0:d7bd7384a37c 725 }
grzemich 0:d7bd7384a37c 726
grzemich 0:d7bd7384a37c 727 /**
grzemich 0:d7bd7384a37c 728 * Receive input function for DNS response packets arriving for the dns UDP pcb.
grzemich 0:d7bd7384a37c 729 *
grzemich 0:d7bd7384a37c 730 * @params see udp.h
grzemich 0:d7bd7384a37c 731 */
grzemich 0:d7bd7384a37c 732 static void
grzemich 0:d7bd7384a37c 733 dns_recv(void *arg, struct udp_pcb *pcb, struct pbuf *p, ip_addr_t *addr, u16_t port)
grzemich 0:d7bd7384a37c 734 {
grzemich 0:d7bd7384a37c 735 u16_t i;
grzemich 0:d7bd7384a37c 736 char *pHostname;
grzemich 0:d7bd7384a37c 737 struct dns_hdr *hdr;
grzemich 0:d7bd7384a37c 738 struct dns_answer ans;
grzemich 0:d7bd7384a37c 739 struct dns_table_entry *pEntry;
grzemich 0:d7bd7384a37c 740 u16_t nquestions, nanswers;
grzemich 0:d7bd7384a37c 741
grzemich 0:d7bd7384a37c 742 LWIP_UNUSED_ARG(arg);
grzemich 0:d7bd7384a37c 743 LWIP_UNUSED_ARG(pcb);
grzemich 0:d7bd7384a37c 744 LWIP_UNUSED_ARG(addr);
grzemich 0:d7bd7384a37c 745 LWIP_UNUSED_ARG(port);
grzemich 0:d7bd7384a37c 746
grzemich 0:d7bd7384a37c 747 /* is the dns message too big ? */
grzemich 0:d7bd7384a37c 748 if (p->tot_len > DNS_MSG_SIZE) {
grzemich 0:d7bd7384a37c 749 LWIP_DEBUGF(DNS_DEBUG, ("dns_recv: pbuf too big\n"));
grzemich 0:d7bd7384a37c 750 /* free pbuf and return */
grzemich 0:d7bd7384a37c 751 goto memerr;
grzemich 0:d7bd7384a37c 752 }
grzemich 0:d7bd7384a37c 753
grzemich 0:d7bd7384a37c 754 /* is the dns message big enough ? */
grzemich 0:d7bd7384a37c 755 if (p->tot_len < (SIZEOF_DNS_HDR + SIZEOF_DNS_QUERY + SIZEOF_DNS_ANSWER)) {
grzemich 0:d7bd7384a37c 756 LWIP_DEBUGF(DNS_DEBUG, ("dns_recv: pbuf too small\n"));
grzemich 0:d7bd7384a37c 757 /* free pbuf and return */
grzemich 0:d7bd7384a37c 758 goto memerr;
grzemich 0:d7bd7384a37c 759 }
grzemich 0:d7bd7384a37c 760
grzemich 0:d7bd7384a37c 761 /* copy dns payload inside static buffer for processing */
grzemich 0:d7bd7384a37c 762 if (pbuf_copy_partial(p, dns_payload, p->tot_len, 0) == p->tot_len) {
grzemich 0:d7bd7384a37c 763 /* The ID in the DNS header should be our entry into the name table. */
grzemich 0:d7bd7384a37c 764 hdr = (struct dns_hdr*)dns_payload;
grzemich 0:d7bd7384a37c 765 i = htons(hdr->id);
grzemich 0:d7bd7384a37c 766 if (i < DNS_TABLE_SIZE) {
grzemich 0:d7bd7384a37c 767 pEntry = &dns_table[i];
grzemich 0:d7bd7384a37c 768 if(pEntry->state == DNS_STATE_ASKING) {
grzemich 0:d7bd7384a37c 769 /* This entry is now completed. */
grzemich 0:d7bd7384a37c 770 pEntry->state = DNS_STATE_DONE;
grzemich 0:d7bd7384a37c 771 pEntry->err = hdr->flags2 & DNS_FLAG2_ERR_MASK;
grzemich 0:d7bd7384a37c 772
grzemich 0:d7bd7384a37c 773 /* We only care about the question(s) and the answers. The authrr
grzemich 0:d7bd7384a37c 774 and the extrarr are simply discarded. */
grzemich 0:d7bd7384a37c 775 nquestions = htons(hdr->numquestions);
grzemich 0:d7bd7384a37c 776 nanswers = htons(hdr->numanswers);
grzemich 0:d7bd7384a37c 777
grzemich 0:d7bd7384a37c 778 /* Check for error. If so, call callback to inform. */
grzemich 0:d7bd7384a37c 779 if (((hdr->flags1 & DNS_FLAG1_RESPONSE) == 0) || (pEntry->err != 0) || (nquestions != 1)) {
grzemich 0:d7bd7384a37c 780 LWIP_DEBUGF(DNS_DEBUG, ("dns_recv: \"%s\": error in flags\n", pEntry->name));
grzemich 0:d7bd7384a37c 781 /* call callback to indicate error, clean up memory and return */
grzemich 0:d7bd7384a37c 782 goto responseerr;
grzemich 0:d7bd7384a37c 783 }
grzemich 0:d7bd7384a37c 784
grzemich 0:d7bd7384a37c 785 #if DNS_DOES_NAME_CHECK
grzemich 0:d7bd7384a37c 786 /* Check if the name in the "question" part match with the name in the entry. */
grzemich 0:d7bd7384a37c 787 if (dns_compare_name((unsigned char *)(pEntry->name), (unsigned char *)dns_payload + SIZEOF_DNS_HDR) != 0) {
grzemich 0:d7bd7384a37c 788 LWIP_DEBUGF(DNS_DEBUG, ("dns_recv: \"%s\": response not match to query\n", pEntry->name));
grzemich 0:d7bd7384a37c 789 /* call callback to indicate error, clean up memory and return */
grzemich 0:d7bd7384a37c 790 goto responseerr;
grzemich 0:d7bd7384a37c 791 }
grzemich 0:d7bd7384a37c 792 #endif /* DNS_DOES_NAME_CHECK */
grzemich 0:d7bd7384a37c 793
grzemich 0:d7bd7384a37c 794 /* Skip the name in the "question" part */
grzemich 0:d7bd7384a37c 795 pHostname = (char *) dns_parse_name((unsigned char *)dns_payload + SIZEOF_DNS_HDR) + SIZEOF_DNS_QUERY;
grzemich 0:d7bd7384a37c 796
grzemich 0:d7bd7384a37c 797 while (nanswers > 0) {
grzemich 0:d7bd7384a37c 798 /* skip answer resource record's host name */
grzemich 0:d7bd7384a37c 799 pHostname = (char *) dns_parse_name((unsigned char *)pHostname);
grzemich 0:d7bd7384a37c 800
grzemich 0:d7bd7384a37c 801 /* Check for IP address type and Internet class. Others are discarded. */
grzemich 0:d7bd7384a37c 802 SMEMCPY(&ans, pHostname, SIZEOF_DNS_ANSWER);
grzemich 0:d7bd7384a37c 803 if((ans.type == PP_HTONS(DNS_RRTYPE_A)) && (ans.cls == PP_HTONS(DNS_RRCLASS_IN)) &&
grzemich 0:d7bd7384a37c 804 (ans.len == PP_HTONS(sizeof(ip_addr_t))) ) {
grzemich 0:d7bd7384a37c 805 /* read the answer resource record's TTL, and maximize it if needed */
grzemich 0:d7bd7384a37c 806 pEntry->ttl = ntohl(ans.ttl);
grzemich 0:d7bd7384a37c 807 if (pEntry->ttl > DNS_MAX_TTL) {
grzemich 0:d7bd7384a37c 808 pEntry->ttl = DNS_MAX_TTL;
grzemich 0:d7bd7384a37c 809 }
grzemich 0:d7bd7384a37c 810 /* read the IP address after answer resource record's header */
grzemich 0:d7bd7384a37c 811 SMEMCPY(&(pEntry->ipaddr), (pHostname+SIZEOF_DNS_ANSWER), sizeof(ip_addr_t));
grzemich 0:d7bd7384a37c 812 LWIP_DEBUGF(DNS_DEBUG, ("dns_recv: \"%s\": response = ", pEntry->name));
grzemich 0:d7bd7384a37c 813 ip_addr_debug_print(DNS_DEBUG, (&(pEntry->ipaddr)));
grzemich 0:d7bd7384a37c 814 LWIP_DEBUGF(DNS_DEBUG, ("\n"));
grzemich 0:d7bd7384a37c 815 /* call specified callback function if provided */
grzemich 0:d7bd7384a37c 816 if (pEntry->found) {
grzemich 0:d7bd7384a37c 817 (*pEntry->found)(pEntry->name, &pEntry->ipaddr, pEntry->arg);
grzemich 0:d7bd7384a37c 818 }
grzemich 0:d7bd7384a37c 819 /* deallocate memory and return */
grzemich 0:d7bd7384a37c 820 goto memerr;
grzemich 0:d7bd7384a37c 821 } else {
grzemich 0:d7bd7384a37c 822 pHostname = pHostname + SIZEOF_DNS_ANSWER + htons(ans.len);
grzemich 0:d7bd7384a37c 823 }
grzemich 0:d7bd7384a37c 824 --nanswers;
grzemich 0:d7bd7384a37c 825 }
grzemich 0:d7bd7384a37c 826 LWIP_DEBUGF(DNS_DEBUG, ("dns_recv: \"%s\": error in response\n", pEntry->name));
grzemich 0:d7bd7384a37c 827 /* call callback to indicate error, clean up memory and return */
grzemich 0:d7bd7384a37c 828 goto responseerr;
grzemich 0:d7bd7384a37c 829 }
grzemich 0:d7bd7384a37c 830 }
grzemich 0:d7bd7384a37c 831 }
grzemich 0:d7bd7384a37c 832
grzemich 0:d7bd7384a37c 833 /* deallocate memory and return */
grzemich 0:d7bd7384a37c 834 goto memerr;
grzemich 0:d7bd7384a37c 835
grzemich 0:d7bd7384a37c 836 responseerr:
grzemich 0:d7bd7384a37c 837 /* ERROR: call specified callback function with NULL as name to indicate an error */
grzemich 0:d7bd7384a37c 838 if (pEntry->found) {
grzemich 0:d7bd7384a37c 839 (*pEntry->found)(pEntry->name, NULL, pEntry->arg);
grzemich 0:d7bd7384a37c 840 }
grzemich 0:d7bd7384a37c 841 /* flush this entry */
grzemich 0:d7bd7384a37c 842 pEntry->state = DNS_STATE_UNUSED;
grzemich 0:d7bd7384a37c 843 pEntry->found = NULL;
grzemich 0:d7bd7384a37c 844
grzemich 0:d7bd7384a37c 845 memerr:
grzemich 0:d7bd7384a37c 846 /* free pbuf */
grzemich 0:d7bd7384a37c 847 pbuf_free(p);
grzemich 0:d7bd7384a37c 848 return;
grzemich 0:d7bd7384a37c 849 }
grzemich 0:d7bd7384a37c 850
grzemich 0:d7bd7384a37c 851 /**
grzemich 0:d7bd7384a37c 852 * Queues a new hostname to resolve and sends out a DNS query for that hostname
grzemich 0:d7bd7384a37c 853 *
grzemich 0:d7bd7384a37c 854 * @param name the hostname that is to be queried
grzemich 0:d7bd7384a37c 855 * @param found a callback founction to be called on success, failure or timeout
grzemich 0:d7bd7384a37c 856 * @param callback_arg argument to pass to the callback function
grzemich 0:d7bd7384a37c 857 * @return @return a err_t return code.
grzemich 0:d7bd7384a37c 858 */
grzemich 0:d7bd7384a37c 859 static err_t
grzemich 0:d7bd7384a37c 860 dns_enqueue(const char *name, dns_found_callback found, void *callback_arg)
grzemich 0:d7bd7384a37c 861 {
grzemich 0:d7bd7384a37c 862 u8_t i;
grzemich 0:d7bd7384a37c 863 u8_t lseq, lseqi;
grzemich 0:d7bd7384a37c 864 struct dns_table_entry *pEntry = NULL;
grzemich 0:d7bd7384a37c 865 size_t namelen;
grzemich 0:d7bd7384a37c 866
grzemich 0:d7bd7384a37c 867 /* search an unused entry, or the oldest one */
grzemich 0:d7bd7384a37c 868 lseq = lseqi = 0;
grzemich 0:d7bd7384a37c 869 for (i = 0; i < DNS_TABLE_SIZE; ++i) {
grzemich 0:d7bd7384a37c 870 pEntry = &dns_table[i];
grzemich 0:d7bd7384a37c 871 /* is it an unused entry ? */
grzemich 0:d7bd7384a37c 872 if (pEntry->state == DNS_STATE_UNUSED)
grzemich 0:d7bd7384a37c 873 break;
grzemich 0:d7bd7384a37c 874
grzemich 0:d7bd7384a37c 875 /* check if this is the oldest completed entry */
grzemich 0:d7bd7384a37c 876 if (pEntry->state == DNS_STATE_DONE) {
grzemich 0:d7bd7384a37c 877 if ((dns_seqno - pEntry->seqno) > lseq) {
grzemich 0:d7bd7384a37c 878 lseq = dns_seqno - pEntry->seqno;
grzemich 0:d7bd7384a37c 879 lseqi = i;
grzemich 0:d7bd7384a37c 880 }
grzemich 0:d7bd7384a37c 881 }
grzemich 0:d7bd7384a37c 882 }
grzemich 0:d7bd7384a37c 883
grzemich 0:d7bd7384a37c 884 /* if we don't have found an unused entry, use the oldest completed one */
grzemich 0:d7bd7384a37c 885 if (i == DNS_TABLE_SIZE) {
grzemich 0:d7bd7384a37c 886 if ((lseqi >= DNS_TABLE_SIZE) || (dns_table[lseqi].state != DNS_STATE_DONE)) {
grzemich 0:d7bd7384a37c 887 /* no entry can't be used now, table is full */
grzemich 0:d7bd7384a37c 888 LWIP_DEBUGF(DNS_DEBUG, ("dns_enqueue: \"%s\": DNS entries table is full\n", name));
grzemich 0:d7bd7384a37c 889 return ERR_MEM;
grzemich 0:d7bd7384a37c 890 } else {
grzemich 0:d7bd7384a37c 891 /* use the oldest completed one */
grzemich 0:d7bd7384a37c 892 i = lseqi;
grzemich 0:d7bd7384a37c 893 pEntry = &dns_table[i];
grzemich 0:d7bd7384a37c 894 }
grzemich 0:d7bd7384a37c 895 }
grzemich 0:d7bd7384a37c 896
grzemich 0:d7bd7384a37c 897 /* use this entry */
grzemich 0:d7bd7384a37c 898 LWIP_DEBUGF(DNS_DEBUG, ("dns_enqueue: \"%s\": use DNS entry %"U16_F"\n", name, (u16_t)(i)));
grzemich 0:d7bd7384a37c 899
grzemich 0:d7bd7384a37c 900 /* fill the entry */
grzemich 0:d7bd7384a37c 901 pEntry->state = DNS_STATE_NEW;
grzemich 0:d7bd7384a37c 902 pEntry->seqno = dns_seqno++;
grzemich 0:d7bd7384a37c 903 pEntry->found = found;
grzemich 0:d7bd7384a37c 904 pEntry->arg = callback_arg;
grzemich 0:d7bd7384a37c 905 namelen = LWIP_MIN(strlen(name), DNS_MAX_NAME_LENGTH-1);
grzemich 0:d7bd7384a37c 906 MEMCPY(pEntry->name, name, namelen);
grzemich 0:d7bd7384a37c 907 pEntry->name[namelen] = 0;
grzemich 0:d7bd7384a37c 908
grzemich 0:d7bd7384a37c 909 /* force to send query without waiting timer */
grzemich 0:d7bd7384a37c 910 dns_check_entry(i);
grzemich 0:d7bd7384a37c 911
grzemich 0:d7bd7384a37c 912 /* dns query is enqueued */
grzemich 0:d7bd7384a37c 913 return ERR_INPROGRESS;
grzemich 0:d7bd7384a37c 914 }
grzemich 0:d7bd7384a37c 915
grzemich 0:d7bd7384a37c 916 /**
grzemich 0:d7bd7384a37c 917 * Resolve a hostname (string) into an IP address.
grzemich 0:d7bd7384a37c 918 * NON-BLOCKING callback version for use with raw API!!!
grzemich 0:d7bd7384a37c 919 *
grzemich 0:d7bd7384a37c 920 * Returns immediately with one of err_t return codes:
grzemich 0:d7bd7384a37c 921 * - ERR_OK if hostname is a valid IP address string or the host
grzemich 0:d7bd7384a37c 922 * name is already in the local names table.
grzemich 0:d7bd7384a37c 923 * - ERR_INPROGRESS enqueue a request to be sent to the DNS server
grzemich 0:d7bd7384a37c 924 * for resolution if no errors are present.
grzemich 0:d7bd7384a37c 925 * - ERR_ARG: dns client not initialized or invalid hostname
grzemich 0:d7bd7384a37c 926 *
grzemich 0:d7bd7384a37c 927 * @param hostname the hostname that is to be queried
grzemich 0:d7bd7384a37c 928 * @param addr pointer to a ip_addr_t where to store the address if it is already
grzemich 0:d7bd7384a37c 929 * cached in the dns_table (only valid if ERR_OK is returned!)
grzemich 0:d7bd7384a37c 930 * @param found a callback function to be called on success, failure or timeout (only if
grzemich 0:d7bd7384a37c 931 * ERR_INPROGRESS is returned!)
grzemich 0:d7bd7384a37c 932 * @param callback_arg argument to pass to the callback function
grzemich 0:d7bd7384a37c 933 * @return a err_t return code.
grzemich 0:d7bd7384a37c 934 */
grzemich 0:d7bd7384a37c 935 err_t
grzemich 0:d7bd7384a37c 936 dns_gethostbyname(const char *hostname, ip_addr_t *addr, dns_found_callback found,
grzemich 0:d7bd7384a37c 937 void *callback_arg)
grzemich 0:d7bd7384a37c 938 {
grzemich 0:d7bd7384a37c 939 u32_t ipaddr;
grzemich 0:d7bd7384a37c 940 /* not initialized or no valid server yet, or invalid addr pointer
grzemich 0:d7bd7384a37c 941 * or invalid hostname or invalid hostname length */
grzemich 0:d7bd7384a37c 942 if ((dns_pcb == NULL) || (addr == NULL) ||
grzemich 0:d7bd7384a37c 943 (!hostname) || (!hostname[0]) ||
grzemich 0:d7bd7384a37c 944 (strlen(hostname) >= DNS_MAX_NAME_LENGTH)) {
grzemich 0:d7bd7384a37c 945 return ERR_ARG;
grzemich 0:d7bd7384a37c 946 }
grzemich 0:d7bd7384a37c 947
grzemich 0:d7bd7384a37c 948 #if LWIP_HAVE_LOOPIF
grzemich 0:d7bd7384a37c 949 if (strcmp(hostname, "localhost")==0) {
grzemich 0:d7bd7384a37c 950 ip_addr_set_loopback(addr);
grzemich 0:d7bd7384a37c 951 return ERR_OK;
grzemich 0:d7bd7384a37c 952 }
grzemich 0:d7bd7384a37c 953 #endif /* LWIP_HAVE_LOOPIF */
grzemich 0:d7bd7384a37c 954
grzemich 0:d7bd7384a37c 955 /* host name already in octet notation? set ip addr and return ERR_OK */
grzemich 0:d7bd7384a37c 956 ipaddr = ipaddr_addr(hostname);
grzemich 0:d7bd7384a37c 957 if (ipaddr == IPADDR_NONE) {
grzemich 0:d7bd7384a37c 958 /* already have this address cached? */
grzemich 0:d7bd7384a37c 959 ipaddr = dns_lookup(hostname);
grzemich 0:d7bd7384a37c 960 }
grzemich 0:d7bd7384a37c 961 if (ipaddr != IPADDR_NONE) {
grzemich 0:d7bd7384a37c 962 ip4_addr_set_u32(addr, ipaddr);
grzemich 0:d7bd7384a37c 963 return ERR_OK;
grzemich 0:d7bd7384a37c 964 }
grzemich 0:d7bd7384a37c 965
grzemich 0:d7bd7384a37c 966 /* queue query with specified callback */
grzemich 0:d7bd7384a37c 967 return dns_enqueue(hostname, found, callback_arg);
grzemich 0:d7bd7384a37c 968 }
grzemich 0:d7bd7384a37c 969
grzemich 0:d7bd7384a37c 970 #endif /* LWIP_DNS */