Rod Coleman / lwip-mbed-2010

Port of LwIP performed by Ralf in 2010. Not recommended for use with recent mbed libraries, but good demos of raw LwIP possible

Dependents:   LwIP_raw_API_serverExample tiny-dtls

Core/lwIP/core/dns.c@0:0791c1fece8e, 2012-09-18 (annotated)

Committer:
RodColeman
Date:
Tue Sep 18 14:41:24 2012 +0000
Revision:
0:0791c1fece8e
[mbed] converted /Eth_TCP_Wei_Server/lwip

Who changed what in which revision?

UserRevisionLine numberNew contents of line
RodColeman 0:0791c1fece8e 1 /**
RodColeman 0:0791c1fece8e 2 * @file
RodColeman 0:0791c1fece8e 3 * DNS - host name to IP address resolver.
RodColeman 0:0791c1fece8e 4 *
RodColeman 0:0791c1fece8e 5 */
RodColeman 0:0791c1fece8e 6
RodColeman 0:0791c1fece8e 7 /**
RodColeman 0:0791c1fece8e 8
RodColeman 0:0791c1fece8e 9 * This file implements a DNS host name to IP address resolver.
RodColeman 0:0791c1fece8e 10
RodColeman 0:0791c1fece8e 11 * Port to lwIP from uIP
RodColeman 0:0791c1fece8e 12 * by Jim Pettinato April 2007
RodColeman 0:0791c1fece8e 13
RodColeman 0:0791c1fece8e 14 * uIP version Copyright (c) 2002-2003, Adam Dunkels.
RodColeman 0:0791c1fece8e 15 * All rights reserved.
RodColeman 0:0791c1fece8e 16 *
RodColeman 0:0791c1fece8e 17 * Redistribution and use in source and binary forms, with or without
RodColeman 0:0791c1fece8e 18 * modification, are permitted provided that the following conditions
RodColeman 0:0791c1fece8e 19 * are met:
RodColeman 0:0791c1fece8e 20 * 1. Redistributions of source code must retain the above copyright
RodColeman 0:0791c1fece8e 21 * notice, this list of conditions and the following disclaimer.
RodColeman 0:0791c1fece8e 22 * 2. Redistributions in binary form must reproduce the above copyright
RodColeman 0:0791c1fece8e 23 * notice, this list of conditions and the following disclaimer in the
RodColeman 0:0791c1fece8e 24 * documentation and/or other materials provided with the distribution.
RodColeman 0:0791c1fece8e 25 * 3. The name of the author may not be used to endorse or promote
RodColeman 0:0791c1fece8e 26 * products derived from this software without specific prior
RodColeman 0:0791c1fece8e 27 * written permission.
RodColeman 0:0791c1fece8e 28 *
RodColeman 0:0791c1fece8e 29 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
RodColeman 0:0791c1fece8e 30 * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
RodColeman 0:0791c1fece8e 31 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
RodColeman 0:0791c1fece8e 32 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
RodColeman 0:0791c1fece8e 33 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
RodColeman 0:0791c1fece8e 34 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
RodColeman 0:0791c1fece8e 35 * GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
RodColeman 0:0791c1fece8e 36 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
RodColeman 0:0791c1fece8e 37 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
RodColeman 0:0791c1fece8e 38 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
RodColeman 0:0791c1fece8e 39 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
RodColeman 0:0791c1fece8e 40 *
RodColeman 0:0791c1fece8e 41 *
RodColeman 0:0791c1fece8e 42 * DNS.C
RodColeman 0:0791c1fece8e 43 *
RodColeman 0:0791c1fece8e 44 * The lwIP DNS resolver functions are used to lookup a host name and
RodColeman 0:0791c1fece8e 45 * map it to a numerical IP address. It maintains a list of resolved
RodColeman 0:0791c1fece8e 46 * hostnames that can be queried with the dns_lookup() function.
RodColeman 0:0791c1fece8e 47 * New hostnames can be resolved using the dns_query() function.
RodColeman 0:0791c1fece8e 48 *
RodColeman 0:0791c1fece8e 49 * The lwIP version of the resolver also adds a non-blocking version of
RodColeman 0:0791c1fece8e 50 * gethostbyname() that will work with a raw API application. This function
RodColeman 0:0791c1fece8e 51 * checks for an IP address string first and converts it if it is valid.
RodColeman 0:0791c1fece8e 52 * gethostbyname() then does a dns_lookup() to see if the name is
RodColeman 0:0791c1fece8e 53 * already in the table. If so, the IP is returned. If not, a query is
RodColeman 0:0791c1fece8e 54 * issued and the function returns with a ERR_INPROGRESS status. The app
RodColeman 0:0791c1fece8e 55 * using the dns client must then go into a waiting state.
RodColeman 0:0791c1fece8e 56 *
RodColeman 0:0791c1fece8e 57 * Once a hostname has been resolved (or found to be non-existent),
RodColeman 0:0791c1fece8e 58 * the resolver code calls a specified callback function (which
RodColeman 0:0791c1fece8e 59 * must be implemented by the module that uses the resolver).
RodColeman 0:0791c1fece8e 60 */
RodColeman 0:0791c1fece8e 61
RodColeman 0:0791c1fece8e 62 /*-----------------------------------------------------------------------------
RodColeman 0:0791c1fece8e 63 * RFC 1035 - Domain names - implementation and specification
RodColeman 0:0791c1fece8e 64 * RFC 2181 - Clarifications to the DNS Specification
RodColeman 0:0791c1fece8e 65 *----------------------------------------------------------------------------*/
RodColeman 0:0791c1fece8e 66
RodColeman 0:0791c1fece8e 67 /** @todo: define good default values (rfc compliance) */
RodColeman 0:0791c1fece8e 68 /** @todo: improve answer parsing, more checkings... */
RodColeman 0:0791c1fece8e 69 /** @todo: check RFC1035 - 7.3. Processing responses */
RodColeman 0:0791c1fece8e 70
RodColeman 0:0791c1fece8e 71 /*-----------------------------------------------------------------------------
RodColeman 0:0791c1fece8e 72 * Includes
RodColeman 0:0791c1fece8e 73 *----------------------------------------------------------------------------*/
RodColeman 0:0791c1fece8e 74
RodColeman 0:0791c1fece8e 75 #include "lwip/opt.h"
RodColeman 0:0791c1fece8e 76
RodColeman 0:0791c1fece8e 77 #if LWIP_DNS /* don't build if not configured for use in lwipopts.h */
RodColeman 0:0791c1fece8e 78
RodColeman 0:0791c1fece8e 79 #include "lwip/udp.h"
RodColeman 0:0791c1fece8e 80 #include "lwip/mem.h"
RodColeman 0:0791c1fece8e 81 #include "lwip/dns.h"
RodColeman 0:0791c1fece8e 82
RodColeman 0:0791c1fece8e 83 #include <string.h>
RodColeman 0:0791c1fece8e 84
RodColeman 0:0791c1fece8e 85 /** DNS server IP address */
RodColeman 0:0791c1fece8e 86 #ifndef DNS_SERVER_ADDRESS
RodColeman 0:0791c1fece8e 87 #define DNS_SERVER_ADDRESS inet_addr("208.67.222.222") /* resolver1.opendns.com */
RodColeman 0:0791c1fece8e 88 #endif
RodColeman 0:0791c1fece8e 89
RodColeman 0:0791c1fece8e 90 /** DNS server port address */
RodColeman 0:0791c1fece8e 91 #ifndef DNS_SERVER_PORT
RodColeman 0:0791c1fece8e 92 #define DNS_SERVER_PORT 53
RodColeman 0:0791c1fece8e 93 #endif
RodColeman 0:0791c1fece8e 94
RodColeman 0:0791c1fece8e 95 /** DNS maximum number of retries when asking for a name, before "timeout". */
RodColeman 0:0791c1fece8e 96 #ifndef DNS_MAX_RETRIES
RodColeman 0:0791c1fece8e 97 #define DNS_MAX_RETRIES 4
RodColeman 0:0791c1fece8e 98 #endif
RodColeman 0:0791c1fece8e 99
RodColeman 0:0791c1fece8e 100 /** DNS resource record max. TTL (one week as default) */
RodColeman 0:0791c1fece8e 101 #ifndef DNS_MAX_TTL
RodColeman 0:0791c1fece8e 102 #define DNS_MAX_TTL 604800
RodColeman 0:0791c1fece8e 103 #endif
RodColeman 0:0791c1fece8e 104
RodColeman 0:0791c1fece8e 105 /* DNS protocol flags */
RodColeman 0:0791c1fece8e 106 #define DNS_FLAG1_RESPONSE 0x80
RodColeman 0:0791c1fece8e 107 #define DNS_FLAG1_OPCODE_STATUS 0x10
RodColeman 0:0791c1fece8e 108 #define DNS_FLAG1_OPCODE_INVERSE 0x08
RodColeman 0:0791c1fece8e 109 #define DNS_FLAG1_OPCODE_STANDARD 0x00
RodColeman 0:0791c1fece8e 110 #define DNS_FLAG1_AUTHORATIVE 0x04
RodColeman 0:0791c1fece8e 111 #define DNS_FLAG1_TRUNC 0x02
RodColeman 0:0791c1fece8e 112 #define DNS_FLAG1_RD 0x01
RodColeman 0:0791c1fece8e 113 #define DNS_FLAG2_RA 0x80
RodColeman 0:0791c1fece8e 114 #define DNS_FLAG2_ERR_MASK 0x0f
RodColeman 0:0791c1fece8e 115 #define DNS_FLAG2_ERR_NONE 0x00
RodColeman 0:0791c1fece8e 116 #define DNS_FLAG2_ERR_NAME 0x03
RodColeman 0:0791c1fece8e 117
RodColeman 0:0791c1fece8e 118 /* DNS protocol states */
RodColeman 0:0791c1fece8e 119 #define DNS_STATE_UNUSED 0
RodColeman 0:0791c1fece8e 120 #define DNS_STATE_NEW 1
RodColeman 0:0791c1fece8e 121 #define DNS_STATE_ASKING 2
RodColeman 0:0791c1fece8e 122 #define DNS_STATE_DONE 3
RodColeman 0:0791c1fece8e 123
RodColeman 0:0791c1fece8e 124
RodColeman 0:0791c1fece8e 125 // XXX: For C++ compatibility
RodColeman 0:0791c1fece8e 126 #define class mclass
RodColeman 0:0791c1fece8e 127
RodColeman 0:0791c1fece8e 128 #ifdef PACK_STRUCT_USE_INCLUDES
RodColeman 0:0791c1fece8e 129 # include "arch/bpstruct.h"
RodColeman 0:0791c1fece8e 130 #endif
RodColeman 0:0791c1fece8e 131 PACK_STRUCT_BEGIN
RodColeman 0:0791c1fece8e 132 /** DNS message header */
RodColeman 0:0791c1fece8e 133 struct dns_hdr {
RodColeman 0:0791c1fece8e 134 PACK_STRUCT_FIELD(u16_t id);
RodColeman 0:0791c1fece8e 135 PACK_STRUCT_FIELD(u8_t flags1);
RodColeman 0:0791c1fece8e 136 PACK_STRUCT_FIELD(u8_t flags2);
RodColeman 0:0791c1fece8e 137 PACK_STRUCT_FIELD(u16_t numquestions);
RodColeman 0:0791c1fece8e 138 PACK_STRUCT_FIELD(u16_t numanswers);
RodColeman 0:0791c1fece8e 139 PACK_STRUCT_FIELD(u16_t numauthrr);
RodColeman 0:0791c1fece8e 140 PACK_STRUCT_FIELD(u16_t numextrarr);
RodColeman 0:0791c1fece8e 141 } PACK_STRUCT_STRUCT;
RodColeman 0:0791c1fece8e 142 PACK_STRUCT_END
RodColeman 0:0791c1fece8e 143 #ifdef PACK_STRUCT_USE_INCLUDES
RodColeman 0:0791c1fece8e 144 # include "arch/epstruct.h"
RodColeman 0:0791c1fece8e 145 #endif
RodColeman 0:0791c1fece8e 146 #define SIZEOF_DNS_HDR 12
RodColeman 0:0791c1fece8e 147
RodColeman 0:0791c1fece8e 148 #ifdef PACK_STRUCT_USE_INCLUDES
RodColeman 0:0791c1fece8e 149 # include "arch/bpstruct.h"
RodColeman 0:0791c1fece8e 150 #endif
RodColeman 0:0791c1fece8e 151 PACK_STRUCT_BEGIN
RodColeman 0:0791c1fece8e 152 /** DNS query message structure */
RodColeman 0:0791c1fece8e 153 struct dns_query {
RodColeman 0:0791c1fece8e 154 /* DNS query record starts with either a domain name or a pointer
RodColeman 0:0791c1fece8e 155 to a name already present somewhere in the packet. */
RodColeman 0:0791c1fece8e 156 PACK_STRUCT_FIELD(u16_t type);
RodColeman 0:0791c1fece8e 157 PACK_STRUCT_FIELD(u16_t class);
RodColeman 0:0791c1fece8e 158 } PACK_STRUCT_STRUCT;
RodColeman 0:0791c1fece8e 159 PACK_STRUCT_END
RodColeman 0:0791c1fece8e 160 #ifdef PACK_STRUCT_USE_INCLUDES
RodColeman 0:0791c1fece8e 161 # include "arch/epstruct.h"
RodColeman 0:0791c1fece8e 162 #endif
RodColeman 0:0791c1fece8e 163 #define SIZEOF_DNS_QUERY 4
RodColeman 0:0791c1fece8e 164
RodColeman 0:0791c1fece8e 165 #ifdef PACK_STRUCT_USE_INCLUDES
RodColeman 0:0791c1fece8e 166 # include "arch/bpstruct.h"
RodColeman 0:0791c1fece8e 167 #endif
RodColeman 0:0791c1fece8e 168 PACK_STRUCT_BEGIN
RodColeman 0:0791c1fece8e 169 /** DNS answer message structure */
RodColeman 0:0791c1fece8e 170 struct dns_answer {
RodColeman 0:0791c1fece8e 171 /* DNS answer record starts with either a domain name or a pointer
RodColeman 0:0791c1fece8e 172 to a name already present somewhere in the packet. */
RodColeman 0:0791c1fece8e 173 PACK_STRUCT_FIELD(u16_t type);
RodColeman 0:0791c1fece8e 174 PACK_STRUCT_FIELD(u16_t class);
RodColeman 0:0791c1fece8e 175 PACK_STRUCT_FIELD(u32_t ttl);
RodColeman 0:0791c1fece8e 176 PACK_STRUCT_FIELD(u16_t len);
RodColeman 0:0791c1fece8e 177 } PACK_STRUCT_STRUCT;
RodColeman 0:0791c1fece8e 178 PACK_STRUCT_END
RodColeman 0:0791c1fece8e 179 #ifdef PACK_STRUCT_USE_INCLUDES
RodColeman 0:0791c1fece8e 180 # include "arch/epstruct.h"
RodColeman 0:0791c1fece8e 181 #endif
RodColeman 0:0791c1fece8e 182 #define SIZEOF_DNS_ANSWER 10
RodColeman 0:0791c1fece8e 183
RodColeman 0:0791c1fece8e 184 /** DNS table entry */
RodColeman 0:0791c1fece8e 185 struct dns_table_entry {
RodColeman 0:0791c1fece8e 186 u8_t state;
RodColeman 0:0791c1fece8e 187 u8_t numdns;
RodColeman 0:0791c1fece8e 188 u8_t tmr;
RodColeman 0:0791c1fece8e 189 u8_t retries;
RodColeman 0:0791c1fece8e 190 u8_t seqno;
RodColeman 0:0791c1fece8e 191 u8_t err;
RodColeman 0:0791c1fece8e 192 u32_t ttl;
RodColeman 0:0791c1fece8e 193 char name[DNS_MAX_NAME_LENGTH];
RodColeman 0:0791c1fece8e 194 struct ip_addr ipaddr;
RodColeman 0:0791c1fece8e 195 /* pointer to callback on DNS query done */
RodColeman 0:0791c1fece8e 196 dns_found_callback found;
RodColeman 0:0791c1fece8e 197 void *arg;
RodColeman 0:0791c1fece8e 198 };
RodColeman 0:0791c1fece8e 199
RodColeman 0:0791c1fece8e 200 #if DNS_LOCAL_HOSTLIST
RodColeman 0:0791c1fece8e 201 /** struct used for local host-list */
RodColeman 0:0791c1fece8e 202 struct local_hostlist_entry {
RodColeman 0:0791c1fece8e 203 /** static hostname */
RodColeman 0:0791c1fece8e 204 const char *name;
RodColeman 0:0791c1fece8e 205 /** static host address in network byteorder */
RodColeman 0:0791c1fece8e 206 u32_t addr;
RodColeman 0:0791c1fece8e 207 struct local_hostlist_entry *next;
RodColeman 0:0791c1fece8e 208 };
RodColeman 0:0791c1fece8e 209
RodColeman 0:0791c1fece8e 210 #if DNS_LOCAL_HOSTLIST_IS_DYNAMIC
RodColeman 0:0791c1fece8e 211 /** Local host-list. For hostnames in this list, no
RodColeman 0:0791c1fece8e 212 * external name resolution is performed */
RodColeman 0:0791c1fece8e 213 static struct local_hostlist_entry *local_hostlist_dynamic;
RodColeman 0:0791c1fece8e 214 #else /* DNS_LOCAL_HOSTLIST_IS_DYNAMIC */
RodColeman 0:0791c1fece8e 215
RodColeman 0:0791c1fece8e 216 /** Defining this allows the local_hostlist_static to be placed in a different
RodColeman 0:0791c1fece8e 217 * linker section (e.g. FLASH) */
RodColeman 0:0791c1fece8e 218 #ifndef DNS_LOCAL_HOSTLIST_STORAGE_PRE
RodColeman 0:0791c1fece8e 219 #define DNS_LOCAL_HOSTLIST_STORAGE_PRE static
RodColeman 0:0791c1fece8e 220 #endif /* DNS_LOCAL_HOSTLIST_STORAGE_PRE */
RodColeman 0:0791c1fece8e 221 /** Defining this allows the local_hostlist_static to be placed in a different
RodColeman 0:0791c1fece8e 222 * linker section (e.g. FLASH) */
RodColeman 0:0791c1fece8e 223 #ifndef DNS_LOCAL_HOSTLIST_STORAGE_POST
RodColeman 0:0791c1fece8e 224 #define DNS_LOCAL_HOSTLIST_STORAGE_POST
RodColeman 0:0791c1fece8e 225 #endif /* DNS_LOCAL_HOSTLIST_STORAGE_POST */
RodColeman 0:0791c1fece8e 226 DNS_LOCAL_HOSTLIST_STORAGE_PRE struct local_hostlist_entry local_hostlist_static[]
RodColeman 0:0791c1fece8e 227 DNS_LOCAL_HOSTLIST_STORAGE_POST = DNS_LOCAL_HOSTLIST_INIT;
RodColeman 0:0791c1fece8e 228
RodColeman 0:0791c1fece8e 229 #endif /* DNS_LOCAL_HOSTLIST_IS_DYNAMIC */
RodColeman 0:0791c1fece8e 230
RodColeman 0:0791c1fece8e 231 static void dns_init_local();
RodColeman 0:0791c1fece8e 232 #endif /* DNS_LOCAL_HOSTLIST */
RodColeman 0:0791c1fece8e 233
RodColeman 0:0791c1fece8e 234
RodColeman 0:0791c1fece8e 235 /* forward declarations */
RodColeman 0:0791c1fece8e 236 static void dns_recv(void *s, struct udp_pcb *pcb, struct pbuf *p, struct ip_addr *addr, u16_t port);
RodColeman 0:0791c1fece8e 237 static void dns_check_entries(void);
RodColeman 0:0791c1fece8e 238
RodColeman 0:0791c1fece8e 239 /*-----------------------------------------------------------------------------
RodColeman 0:0791c1fece8e 240 * Globales
RodColeman 0:0791c1fece8e 241 *----------------------------------------------------------------------------*/
RodColeman 0:0791c1fece8e 242
RodColeman 0:0791c1fece8e 243 /* DNS variables */
RodColeman 0:0791c1fece8e 244 static struct udp_pcb *dns_pcb;
RodColeman 0:0791c1fece8e 245 static u8_t dns_seqno;
RodColeman 0:0791c1fece8e 246 static struct dns_table_entry dns_table[DNS_TABLE_SIZE] MEM_POSITION;
RodColeman 0:0791c1fece8e 247 static struct ip_addr dns_servers[DNS_MAX_SERVERS] MEM_POSITION;
RodColeman 0:0791c1fece8e 248
RodColeman 0:0791c1fece8e 249 #if (DNS_USES_STATIC_BUF == 1)
RodColeman 0:0791c1fece8e 250 static u8_t dns_payload[DNS_MSG_SIZE] MEM_POSITION;
RodColeman 0:0791c1fece8e 251 #endif /* (DNS_USES_STATIC_BUF == 1) */
RodColeman 0:0791c1fece8e 252
RodColeman 0:0791c1fece8e 253 /**
RodColeman 0:0791c1fece8e 254 * Initialize the resolver: set up the UDP pcb and configure the default server
RodColeman 0:0791c1fece8e 255 * (DNS_SERVER_ADDRESS).
RodColeman 0:0791c1fece8e 256 */
RodColeman 0:0791c1fece8e 257 void
RodColeman 0:0791c1fece8e 258 dns_init()
RodColeman 0:0791c1fece8e 259 {
RodColeman 0:0791c1fece8e 260 struct ip_addr dnsserver;
RodColeman 0:0791c1fece8e 261
RodColeman 0:0791c1fece8e 262 /* initialize default DNS server address */
RodColeman 0:0791c1fece8e 263 dnsserver.addr = DNS_SERVER_ADDRESS;
RodColeman 0:0791c1fece8e 264
RodColeman 0:0791c1fece8e 265 LWIP_DEBUGF(DNS_DEBUG, ("dns_init: initializing\n"));
RodColeman 0:0791c1fece8e 266
RodColeman 0:0791c1fece8e 267 /* if dns client not yet initialized... */
RodColeman 0:0791c1fece8e 268 if (dns_pcb == NULL) {
RodColeman 0:0791c1fece8e 269 dns_pcb = udp_new();
RodColeman 0:0791c1fece8e 270
RodColeman 0:0791c1fece8e 271 if (dns_pcb != NULL) {
RodColeman 0:0791c1fece8e 272 /* initialize DNS table not needed (initialized to zero since it is a
RodColeman 0:0791c1fece8e 273 * global variable) */
RodColeman 0:0791c1fece8e 274 LWIP_ASSERT("For implicit initialization to work, DNS_STATE_UNUSED needs to be 0",
RodColeman 0:0791c1fece8e 275 DNS_STATE_UNUSED == 0);
RodColeman 0:0791c1fece8e 276
RodColeman 0:0791c1fece8e 277 /* initialize DNS client */
RodColeman 0:0791c1fece8e 278 udp_bind(dns_pcb, IP_ADDR_ANY, 0);
RodColeman 0:0791c1fece8e 279 udp_recv(dns_pcb, dns_recv, NULL);
RodColeman 0:0791c1fece8e 280
RodColeman 0:0791c1fece8e 281 /* initialize default DNS primary server */
RodColeman 0:0791c1fece8e 282 dns_setserver(0, &dnsserver);
RodColeman 0:0791c1fece8e 283 }
RodColeman 0:0791c1fece8e 284 }
RodColeman 0:0791c1fece8e 285 #if DNS_LOCAL_HOSTLIST
RodColeman 0:0791c1fece8e 286 dns_init_local();
RodColeman 0:0791c1fece8e 287 #endif
RodColeman 0:0791c1fece8e 288 }
RodColeman 0:0791c1fece8e 289
RodColeman 0:0791c1fece8e 290 /**
RodColeman 0:0791c1fece8e 291 * Initialize one of the DNS servers.
RodColeman 0:0791c1fece8e 292 *
RodColeman 0:0791c1fece8e 293 * @param numdns the index of the DNS server to set must be < DNS_MAX_SERVERS
RodColeman 0:0791c1fece8e 294 * @param dnsserver IP address of the DNS server to set
RodColeman 0:0791c1fece8e 295 */
RodColeman 0:0791c1fece8e 296 void
RodColeman 0:0791c1fece8e 297 dns_setserver(u8_t numdns, struct ip_addr *dnsserver)
RodColeman 0:0791c1fece8e 298 {
RodColeman 0:0791c1fece8e 299 if ((numdns < DNS_MAX_SERVERS) && (dns_pcb != NULL) &&
RodColeman 0:0791c1fece8e 300 (dnsserver != NULL) && (dnsserver->addr !=0 )) {
RodColeman 0:0791c1fece8e 301 dns_servers[numdns] = (*dnsserver);
RodColeman 0:0791c1fece8e 302 }
RodColeman 0:0791c1fece8e 303 }
RodColeman 0:0791c1fece8e 304
RodColeman 0:0791c1fece8e 305 /**
RodColeman 0:0791c1fece8e 306 * Obtain one of the currently configured DNS server.
RodColeman 0:0791c1fece8e 307 *
RodColeman 0:0791c1fece8e 308 * @param numdns the index of the DNS server
RodColeman 0:0791c1fece8e 309 * @return IP address of the indexed DNS server or "ip_addr_any" if the DNS
RodColeman 0:0791c1fece8e 310 * server has not been configured.
RodColeman 0:0791c1fece8e 311 */
RodColeman 0:0791c1fece8e 312 struct ip_addr
RodColeman 0:0791c1fece8e 313 dns_getserver(u8_t numdns)
RodColeman 0:0791c1fece8e 314 {
RodColeman 0:0791c1fece8e 315 if (numdns < DNS_MAX_SERVERS) {
RodColeman 0:0791c1fece8e 316 return dns_servers[numdns];
RodColeman 0:0791c1fece8e 317 } else {
RodColeman 0:0791c1fece8e 318 return *IP_ADDR_ANY;
RodColeman 0:0791c1fece8e 319 }
RodColeman 0:0791c1fece8e 320 }
RodColeman 0:0791c1fece8e 321
RodColeman 0:0791c1fece8e 322 /**
RodColeman 0:0791c1fece8e 323 * The DNS resolver client timer - handle retries and timeouts and should
RodColeman 0:0791c1fece8e 324 * be called every DNS_TMR_INTERVAL milliseconds (every second by default).
RodColeman 0:0791c1fece8e 325 */
RodColeman 0:0791c1fece8e 326 void
RodColeman 0:0791c1fece8e 327 dns_tmr(void)
RodColeman 0:0791c1fece8e 328 {
RodColeman 0:0791c1fece8e 329 if (dns_pcb != NULL) {
RodColeman 0:0791c1fece8e 330 LWIP_DEBUGF(DNS_DEBUG, ("dns_tmr: dns_check_entries\n"));
RodColeman 0:0791c1fece8e 331 dns_check_entries();
RodColeman 0:0791c1fece8e 332 }
RodColeman 0:0791c1fece8e 333 }
RodColeman 0:0791c1fece8e 334
RodColeman 0:0791c1fece8e 335 #if DNS_LOCAL_HOSTLIST
RodColeman 0:0791c1fece8e 336 static void
RodColeman 0:0791c1fece8e 337 dns_init_local()
RodColeman 0:0791c1fece8e 338 {
RodColeman 0:0791c1fece8e 339 #if DNS_LOCAL_HOSTLIST_IS_DYNAMIC && defined(DNS_LOCAL_HOSTLIST_INIT)
RodColeman 0:0791c1fece8e 340 int i;
RodColeman 0:0791c1fece8e 341 struct local_hostlist_entry *entry;
RodColeman 0:0791c1fece8e 342 /* Dynamic: copy entries from DNS_LOCAL_HOSTLIST_INIT to list */
RodColeman 0:0791c1fece8e 343 struct local_hostlist_entry local_hostlist_init[] = DNS_LOCAL_HOSTLIST_INIT;
RodColeman 0:0791c1fece8e 344 for (i = 0; i < sizeof(local_hostlist_init) / sizeof(struct local_hostlist_entry); i++) {
RodColeman 0:0791c1fece8e 345 entry = mem_malloc(sizeof(struct local_hostlist_entry));
RodColeman 0:0791c1fece8e 346 LWIP_ASSERT("mem-error in dns_init_local", entry != NULL);
RodColeman 0:0791c1fece8e 347 if (entry != NULL) {
RodColeman 0:0791c1fece8e 348 struct local_hostlist_entry *init_entry = &local_hostlist_init[i];
RodColeman 0:0791c1fece8e 349 entry->name = init_entry->name;
RodColeman 0:0791c1fece8e 350 entry->addr = init_entry->addr;
RodColeman 0:0791c1fece8e 351 entry->next = local_hostlist_dynamic;
RodColeman 0:0791c1fece8e 352 local_hostlist_dynamic = entry;
RodColeman 0:0791c1fece8e 353 }
RodColeman 0:0791c1fece8e 354 }
RodColeman 0:0791c1fece8e 355 #endif /* DNS_LOCAL_HOSTLIST_IS_DYNAMIC && defined(DNS_LOCAL_HOSTLIST_INIT) */
RodColeman 0:0791c1fece8e 356 }
RodColeman 0:0791c1fece8e 357
RodColeman 0:0791c1fece8e 358 /**
RodColeman 0:0791c1fece8e 359 * Scans the local host-list for a hostname.
RodColeman 0:0791c1fece8e 360 *
RodColeman 0:0791c1fece8e 361 * @param hostname Hostname to look for in the local host-list
RodColeman 0:0791c1fece8e 362 * @return The first IP address for the hostname in the local host-list or
RodColeman 0:0791c1fece8e 363 * INADDR_NONE if not found.
RodColeman 0:0791c1fece8e 364 */
RodColeman 0:0791c1fece8e 365 static u32_t
RodColeman 0:0791c1fece8e 366 dns_lookup_local(const char *hostname)
RodColeman 0:0791c1fece8e 367 {
RodColeman 0:0791c1fece8e 368 #if DNS_LOCAL_HOSTLIST_IS_DYNAMIC
RodColeman 0:0791c1fece8e 369 struct local_hostlist_entry *entry = local_hostlist_dynamic;
RodColeman 0:0791c1fece8e 370 while(entry != NULL) {
RodColeman 0:0791c1fece8e 371 if(strcmp(entry->name, hostname) == 0) {
RodColeman 0:0791c1fece8e 372 return entry->addr;
RodColeman 0:0791c1fece8e 373 }
RodColeman 0:0791c1fece8e 374 entry = entry->next;
RodColeman 0:0791c1fece8e 375 }
RodColeman 0:0791c1fece8e 376 #else /* DNS_LOCAL_HOSTLIST_IS_DYNAMIC */
RodColeman 0:0791c1fece8e 377 int i;
RodColeman 0:0791c1fece8e 378 for (i = 0; i < sizeof(local_hostlist_static) / sizeof(struct local_hostlist_entry); i++) {
RodColeman 0:0791c1fece8e 379 if(strcmp(local_hostlist_static[i].name, hostname) == 0) {
RodColeman 0:0791c1fece8e 380 return local_hostlist_static[i].addr;
RodColeman 0:0791c1fece8e 381 }
RodColeman 0:0791c1fece8e 382 }
RodColeman 0:0791c1fece8e 383 #endif /* DNS_LOCAL_HOSTLIST_IS_DYNAMIC */
RodColeman 0:0791c1fece8e 384 return INADDR_NONE;
RodColeman 0:0791c1fece8e 385 }
RodColeman 0:0791c1fece8e 386
RodColeman 0:0791c1fece8e 387 #if DNS_LOCAL_HOSTLIST_IS_DYNAMIC
RodColeman 0:0791c1fece8e 388 /** Remove all entries from the local host-list for a specific hostname
RodColeman 0:0791c1fece8e 389 * and/or IP addess
RodColeman 0:0791c1fece8e 390 *
RodColeman 0:0791c1fece8e 391 * @param hostname hostname for which entries shall be removed from the local
RodColeman 0:0791c1fece8e 392 * host-list
RodColeman 0:0791c1fece8e 393 * @param addr address for which entries shall be removed from the local host-list
RodColeman 0:0791c1fece8e 394 * @return the number of removed entries
RodColeman 0:0791c1fece8e 395 */
RodColeman 0:0791c1fece8e 396 int
RodColeman 0:0791c1fece8e 397 dns_local_removehost(const char *hostname, const struct ip_addr *addr)
RodColeman 0:0791c1fece8e 398 {
RodColeman 0:0791c1fece8e 399 int removed = 0;
RodColeman 0:0791c1fece8e 400 struct local_hostlist_entry *entry = local_hostlist_dynamic;
RodColeman 0:0791c1fece8e 401 struct local_hostlist_entry *last_entry = NULL;
RodColeman 0:0791c1fece8e 402 while (entry != NULL) {
RodColeman 0:0791c1fece8e 403 if (((hostname == NULL) || !strcmp(entry->name, hostname)) &&
RodColeman 0:0791c1fece8e 404 ((addr == NULL) || (entry->addr == addr->addr))) {
RodColeman 0:0791c1fece8e 405 struct local_hostlist_entry *free_entry;
RodColeman 0:0791c1fece8e 406 if (last_entry != NULL) {
RodColeman 0:0791c1fece8e 407 last_entry->next = entry->next;
RodColeman 0:0791c1fece8e 408 } else {
RodColeman 0:0791c1fece8e 409 local_hostlist_dynamic = entry->next;
RodColeman 0:0791c1fece8e 410 }
RodColeman 0:0791c1fece8e 411 free_entry = entry;
RodColeman 0:0791c1fece8e 412 entry = entry->next;
RodColeman 0:0791c1fece8e 413 mem_free(free_entry);
RodColeman 0:0791c1fece8e 414 removed++;
RodColeman 0:0791c1fece8e 415 } else {
RodColeman 0:0791c1fece8e 416 last_entry = entry;
RodColeman 0:0791c1fece8e 417 entry = entry->next;
RodColeman 0:0791c1fece8e 418 }
RodColeman 0:0791c1fece8e 419 }
RodColeman 0:0791c1fece8e 420 return removed;
RodColeman 0:0791c1fece8e 421 }
RodColeman 0:0791c1fece8e 422
RodColeman 0:0791c1fece8e 423 /**
RodColeman 0:0791c1fece8e 424 * Add a hostname/IP address pair to the local host-list.
RodColeman 0:0791c1fece8e 425 * Duplicates are not checked.
RodColeman 0:0791c1fece8e 426 *
RodColeman 0:0791c1fece8e 427 * @param hostname hostname of the new entry
RodColeman 0:0791c1fece8e 428 * @param addr IP address of the new entry
RodColeman 0:0791c1fece8e 429 * @return ERR_OK if succeeded or ERR_MEM on memory error
RodColeman 0:0791c1fece8e 430 */
RodColeman 0:0791c1fece8e 431 err_t
RodColeman 0:0791c1fece8e 432 dns_local_addhost(const char *hostname, const struct ip_addr *addr)
RodColeman 0:0791c1fece8e 433 {
RodColeman 0:0791c1fece8e 434 struct local_hostlist_entry *entry;
RodColeman 0:0791c1fece8e 435 entry = mem_malloc(sizeof(struct local_hostlist_entry));
RodColeman 0:0791c1fece8e 436 if (entry == NULL) {
RodColeman 0:0791c1fece8e 437 return ERR_MEM;
RodColeman 0:0791c1fece8e 438 }
RodColeman 0:0791c1fece8e 439 entry->name = hostname;
RodColeman 0:0791c1fece8e 440 entry->addr = addr->addr;
RodColeman 0:0791c1fece8e 441 entry->next = local_hostlist_dynamic;
RodColeman 0:0791c1fece8e 442 local_hostlist_dynamic = entry;
RodColeman 0:0791c1fece8e 443 return ERR_OK;
RodColeman 0:0791c1fece8e 444 }
RodColeman 0:0791c1fece8e 445 #endif /* DNS_LOCAL_HOSTLIST_IS_DYNAMIC*/
RodColeman 0:0791c1fece8e 446 #endif /* DNS_LOCAL_HOSTLIST */
RodColeman 0:0791c1fece8e 447
RodColeman 0:0791c1fece8e 448 /**
RodColeman 0:0791c1fece8e 449 * Look up a hostname in the array of known hostnames.
RodColeman 0:0791c1fece8e 450 *
RodColeman 0:0791c1fece8e 451 * @note This function only looks in the internal array of known
RodColeman 0:0791c1fece8e 452 * hostnames, it does not send out a query for the hostname if none
RodColeman 0:0791c1fece8e 453 * was found. The function dns_enqueue() can be used to send a query
RodColeman 0:0791c1fece8e 454 * for a hostname.
RodColeman 0:0791c1fece8e 455 *
RodColeman 0:0791c1fece8e 456 * @param name the hostname to look up
RodColeman 0:0791c1fece8e 457 * @return the hostname's IP address, as u32_t (instead of struct ip_addr to
RodColeman 0:0791c1fece8e 458 * better check for failure: != INADDR_NONE) or INADDR_NONE if the hostname
RodColeman 0:0791c1fece8e 459 * was not found in the cached dns_table.
RodColeman 0:0791c1fece8e 460 */
RodColeman 0:0791c1fece8e 461 static u32_t
RodColeman 0:0791c1fece8e 462 dns_lookup(const char *name)
RodColeman 0:0791c1fece8e 463 {
RodColeman 0:0791c1fece8e 464 u8_t i;
RodColeman 0:0791c1fece8e 465 #if DNS_LOCAL_HOSTLIST || defined(DNS_LOOKUP_LOCAL_EXTERN)
RodColeman 0:0791c1fece8e 466 u32_t addr;
RodColeman 0:0791c1fece8e 467 #endif /* DNS_LOCAL_HOSTLIST || defined(DNS_LOOKUP_LOCAL_EXTERN) */
RodColeman 0:0791c1fece8e 468 #if DNS_LOCAL_HOSTLIST
RodColeman 0:0791c1fece8e 469 if ((addr = dns_lookup_local(name)) != INADDR_NONE) {
RodColeman 0:0791c1fece8e 470 return addr;
RodColeman 0:0791c1fece8e 471 }
RodColeman 0:0791c1fece8e 472 #endif /* DNS_LOCAL_HOSTLIST */
RodColeman 0:0791c1fece8e 473 #ifdef DNS_LOOKUP_LOCAL_EXTERN
RodColeman 0:0791c1fece8e 474 if((addr = DNS_LOOKUP_LOCAL_EXTERN(name)) != INADDR_NONE) {
RodColeman 0:0791c1fece8e 475 return addr;
RodColeman 0:0791c1fece8e 476 }
RodColeman 0:0791c1fece8e 477 #endif /* DNS_LOOKUP_LOCAL_EXTERN */
RodColeman 0:0791c1fece8e 478
RodColeman 0:0791c1fece8e 479 /* Walk through name list, return entry if found. If not, return NULL. */
RodColeman 0:0791c1fece8e 480 for (i = 0; i < DNS_TABLE_SIZE; ++i) {
RodColeman 0:0791c1fece8e 481 if ((dns_table[i].state == DNS_STATE_DONE) &&
RodColeman 0:0791c1fece8e 482 (strcmp(name, dns_table[i].name) == 0)) {
RodColeman 0:0791c1fece8e 483 LWIP_DEBUGF(DNS_DEBUG, ("dns_lookup: \"%s\": found = ", name));
RodColeman 0:0791c1fece8e 484 ip_addr_debug_print(DNS_DEBUG, &(dns_table[i].ipaddr));
RodColeman 0:0791c1fece8e 485 LWIP_DEBUGF(DNS_DEBUG, ("\n"));
RodColeman 0:0791c1fece8e 486 return dns_table[i].ipaddr.addr;
RodColeman 0:0791c1fece8e 487 }
RodColeman 0:0791c1fece8e 488 }
RodColeman 0:0791c1fece8e 489
RodColeman 0:0791c1fece8e 490 return INADDR_NONE;
RodColeman 0:0791c1fece8e 491 }
RodColeman 0:0791c1fece8e 492
RodColeman 0:0791c1fece8e 493 #if DNS_DOES_NAME_CHECK
RodColeman 0:0791c1fece8e 494 /**
RodColeman 0:0791c1fece8e 495 * Compare the "dotted" name "query" with the encoded name "response"
RodColeman 0:0791c1fece8e 496 * to make sure an answer from the DNS server matches the current dns_table
RodColeman 0:0791c1fece8e 497 * entry (otherwise, answers might arrive late for hostname not on the list
RodColeman 0:0791c1fece8e 498 * any more).
RodColeman 0:0791c1fece8e 499 *
RodColeman 0:0791c1fece8e 500 * @param query hostname (not encoded) from the dns_table
RodColeman 0:0791c1fece8e 501 * @param response encoded hostname in the DNS response
RodColeman 0:0791c1fece8e 502 * @return 0: names equal; 1: names differ
RodColeman 0:0791c1fece8e 503 */
RodColeman 0:0791c1fece8e 504 static u8_t
RodColeman 0:0791c1fece8e 505 dns_compare_name(unsigned char *query, unsigned char *response)
RodColeman 0:0791c1fece8e 506 {
RodColeman 0:0791c1fece8e 507 unsigned char n;
RodColeman 0:0791c1fece8e 508
RodColeman 0:0791c1fece8e 509 do {
RodColeman 0:0791c1fece8e 510 n = *response++;
RodColeman 0:0791c1fece8e 511 /** @see RFC 1035 - 4.1.4. Message compression */
RodColeman 0:0791c1fece8e 512 if ((n & 0xc0) == 0xc0) {
RodColeman 0:0791c1fece8e 513 /* Compressed name */
RodColeman 0:0791c1fece8e 514 break;
RodColeman 0:0791c1fece8e 515 } else {
RodColeman 0:0791c1fece8e 516 /* Not compressed name */
RodColeman 0:0791c1fece8e 517 while (n > 0) {
RodColeman 0:0791c1fece8e 518 if ((*query) != (*response)) {
RodColeman 0:0791c1fece8e 519 return 1;
RodColeman 0:0791c1fece8e 520 }
RodColeman 0:0791c1fece8e 521 ++response;
RodColeman 0:0791c1fece8e 522 ++query;
RodColeman 0:0791c1fece8e 523 --n;
RodColeman 0:0791c1fece8e 524 };
RodColeman 0:0791c1fece8e 525 ++query;
RodColeman 0:0791c1fece8e 526 }
RodColeman 0:0791c1fece8e 527 } while (*response != 0);
RodColeman 0:0791c1fece8e 528
RodColeman 0:0791c1fece8e 529 return 0;
RodColeman 0:0791c1fece8e 530 }
RodColeman 0:0791c1fece8e 531 #endif /* DNS_DOES_NAME_CHECK */
RodColeman 0:0791c1fece8e 532
RodColeman 0:0791c1fece8e 533 /**
RodColeman 0:0791c1fece8e 534 * Walk through a compact encoded DNS name and return the end of the name.
RodColeman 0:0791c1fece8e 535 *
RodColeman 0:0791c1fece8e 536 * @param query encoded DNS name in the DNS server response
RodColeman 0:0791c1fece8e 537 * @return end of the name
RodColeman 0:0791c1fece8e 538 */
RodColeman 0:0791c1fece8e 539 static unsigned char *
RodColeman 0:0791c1fece8e 540 dns_parse_name(unsigned char *query)
RodColeman 0:0791c1fece8e 541 {
RodColeman 0:0791c1fece8e 542 unsigned char n;
RodColeman 0:0791c1fece8e 543
RodColeman 0:0791c1fece8e 544 do {
RodColeman 0:0791c1fece8e 545 n = *query++;
RodColeman 0:0791c1fece8e 546 /** @see RFC 1035 - 4.1.4. Message compression */
RodColeman 0:0791c1fece8e 547 if ((n & 0xc0) == 0xc0) {
RodColeman 0:0791c1fece8e 548 /* Compressed name */
RodColeman 0:0791c1fece8e 549 break;
RodColeman 0:0791c1fece8e 550 } else {
RodColeman 0:0791c1fece8e 551 /* Not compressed name */
RodColeman 0:0791c1fece8e 552 while (n > 0) {
RodColeman 0:0791c1fece8e 553 ++query;
RodColeman 0:0791c1fece8e 554 --n;
RodColeman 0:0791c1fece8e 555 };
RodColeman 0:0791c1fece8e 556 }
RodColeman 0:0791c1fece8e 557 } while (*query != 0);
RodColeman 0:0791c1fece8e 558
RodColeman 0:0791c1fece8e 559 return query + 1;
RodColeman 0:0791c1fece8e 560 }
RodColeman 0:0791c1fece8e 561
RodColeman 0:0791c1fece8e 562 /**
RodColeman 0:0791c1fece8e 563 * Send a DNS query packet.
RodColeman 0:0791c1fece8e 564 *
RodColeman 0:0791c1fece8e 565 * @param numdns index of the DNS server in the dns_servers table
RodColeman 0:0791c1fece8e 566 * @param name hostname to query
RodColeman 0:0791c1fece8e 567 * @param id index of the hostname in dns_table, used as transaction ID in the
RodColeman 0:0791c1fece8e 568 * DNS query packet
RodColeman 0:0791c1fece8e 569 * @return ERR_OK if packet is sent; an err_t indicating the problem otherwise
RodColeman 0:0791c1fece8e 570 */
RodColeman 0:0791c1fece8e 571 static err_t
RodColeman 0:0791c1fece8e 572 dns_send(u8_t numdns, const char* name, u8_t id)
RodColeman 0:0791c1fece8e 573 {
RodColeman 0:0791c1fece8e 574 err_t err;
RodColeman 0:0791c1fece8e 575 struct dns_hdr *hdr;
RodColeman 0:0791c1fece8e 576 struct dns_query qry;
RodColeman 0:0791c1fece8e 577 struct pbuf *p;
RodColeman 0:0791c1fece8e 578 char *query, *nptr;
RodColeman 0:0791c1fece8e 579 const char *pHostname;
RodColeman 0:0791c1fece8e 580 u8_t n;
RodColeman 0:0791c1fece8e 581
RodColeman 0:0791c1fece8e 582 LWIP_DEBUGF(DNS_DEBUG, ("dns_send: dns_servers[%"U16_F"] \"%s\": request\n",
RodColeman 0:0791c1fece8e 583 (u16_t)(numdns), name));
RodColeman 0:0791c1fece8e 584 LWIP_ASSERT("dns server out of array", numdns < DNS_MAX_SERVERS);
RodColeman 0:0791c1fece8e 585 LWIP_ASSERT("dns server has no IP address set", dns_servers[numdns].addr != 0);
RodColeman 0:0791c1fece8e 586
RodColeman 0:0791c1fece8e 587 /* if here, we have either a new query or a retry on a previous query to process */
RodColeman 0:0791c1fece8e 588 p = pbuf_alloc(PBUF_TRANSPORT, SIZEOF_DNS_HDR + DNS_MAX_NAME_LENGTH +
RodColeman 0:0791c1fece8e 589 SIZEOF_DNS_QUERY, PBUF_RAM);
RodColeman 0:0791c1fece8e 590 if (p != NULL) {
RodColeman 0:0791c1fece8e 591 LWIP_ASSERT("pbuf must be in one piece", p->next == NULL);
RodColeman 0:0791c1fece8e 592 /* fill dns header */
RodColeman 0:0791c1fece8e 593 hdr = (struct dns_hdr*)p->payload;
RodColeman 0:0791c1fece8e 594 memset(hdr, 0, SIZEOF_DNS_HDR);
RodColeman 0:0791c1fece8e 595 hdr->id = htons(id);
RodColeman 0:0791c1fece8e 596 hdr->flags1 = DNS_FLAG1_RD;
RodColeman 0:0791c1fece8e 597 hdr->numquestions = htons(1);
RodColeman 0:0791c1fece8e 598 query = (char*)hdr + SIZEOF_DNS_HDR;
RodColeman 0:0791c1fece8e 599 pHostname = name;
RodColeman 0:0791c1fece8e 600 --pHostname;
RodColeman 0:0791c1fece8e 601
RodColeman 0:0791c1fece8e 602 /* convert hostname into suitable query format. */
RodColeman 0:0791c1fece8e 603 do {
RodColeman 0:0791c1fece8e 604 ++pHostname;
RodColeman 0:0791c1fece8e 605 nptr = query;
RodColeman 0:0791c1fece8e 606 ++query;
RodColeman 0:0791c1fece8e 607 for(n = 0; *pHostname != '.' && *pHostname != 0; ++pHostname) {
RodColeman 0:0791c1fece8e 608 *query = *pHostname;
RodColeman 0:0791c1fece8e 609 ++query;
RodColeman 0:0791c1fece8e 610 ++n;
RodColeman 0:0791c1fece8e 611 }
RodColeman 0:0791c1fece8e 612 *nptr = n;
RodColeman 0:0791c1fece8e 613 } while(*pHostname != 0);
RodColeman 0:0791c1fece8e 614 *query++='\0';
RodColeman 0:0791c1fece8e 615
RodColeman 0:0791c1fece8e 616 /* fill dns query */
RodColeman 0:0791c1fece8e 617 qry.type = htons(DNS_RRTYPE_A);
RodColeman 0:0791c1fece8e 618 qry.class = htons(DNS_RRCLASS_IN);
RodColeman 0:0791c1fece8e 619 MEMCPY( query, &qry, SIZEOF_DNS_QUERY);
RodColeman 0:0791c1fece8e 620
RodColeman 0:0791c1fece8e 621 /* resize pbuf to the exact dns query */
RodColeman 0:0791c1fece8e 622 pbuf_realloc(p, (query + SIZEOF_DNS_QUERY) - ((char*)(p->payload)));
RodColeman 0:0791c1fece8e 623
RodColeman 0:0791c1fece8e 624 /* connect to the server for faster receiving */
RodColeman 0:0791c1fece8e 625 udp_connect(dns_pcb, &dns_servers[numdns], DNS_SERVER_PORT);
RodColeman 0:0791c1fece8e 626 /* send dns packet */
RodColeman 0:0791c1fece8e 627 err = udp_sendto(dns_pcb, p, &dns_servers[numdns], DNS_SERVER_PORT);
RodColeman 0:0791c1fece8e 628
RodColeman 0:0791c1fece8e 629 /* free pbuf */
RodColeman 0:0791c1fece8e 630 pbuf_free(p);
RodColeman 0:0791c1fece8e 631 } else {
RodColeman 0:0791c1fece8e 632 err = ERR_MEM;
RodColeman 0:0791c1fece8e 633 }
RodColeman 0:0791c1fece8e 634
RodColeman 0:0791c1fece8e 635 return err;
RodColeman 0:0791c1fece8e 636 }
RodColeman 0:0791c1fece8e 637
RodColeman 0:0791c1fece8e 638 /**
RodColeman 0:0791c1fece8e 639 * dns_check_entry() - see if pEntry has not yet been queried and, if so, sends out a query.
RodColeman 0:0791c1fece8e 640 * Check an entry in the dns_table:
RodColeman 0:0791c1fece8e 641 * - send out query for new entries
RodColeman 0:0791c1fece8e 642 * - retry old pending entries on timeout (also with different servers)
RodColeman 0:0791c1fece8e 643 * - remove completed entries from the table if their TTL has expired
RodColeman 0:0791c1fece8e 644 *
RodColeman 0:0791c1fece8e 645 * @param i index of the dns_table entry to check
RodColeman 0:0791c1fece8e 646 */
RodColeman 0:0791c1fece8e 647 static void
RodColeman 0:0791c1fece8e 648 dns_check_entry(u8_t i)
RodColeman 0:0791c1fece8e 649 {
RodColeman 0:0791c1fece8e 650 struct dns_table_entry *pEntry = &dns_table[i];
RodColeman 0:0791c1fece8e 651
RodColeman 0:0791c1fece8e 652 LWIP_ASSERT("array index out of bounds", i < DNS_TABLE_SIZE);
RodColeman 0:0791c1fece8e 653
RodColeman 0:0791c1fece8e 654 switch(pEntry->state) {
RodColeman 0:0791c1fece8e 655
RodColeman 0:0791c1fece8e 656 case DNS_STATE_NEW: {
RodColeman 0:0791c1fece8e 657 /* initialize new entry */
RodColeman 0:0791c1fece8e 658 pEntry->state = DNS_STATE_ASKING;
RodColeman 0:0791c1fece8e 659 pEntry->numdns = 0;
RodColeman 0:0791c1fece8e 660 pEntry->tmr = 1;
RodColeman 0:0791c1fece8e 661 pEntry->retries = 0;
RodColeman 0:0791c1fece8e 662
RodColeman 0:0791c1fece8e 663 /* send DNS packet for this entry */
RodColeman 0:0791c1fece8e 664 dns_send(pEntry->numdns, pEntry->name, i);
RodColeman 0:0791c1fece8e 665 break;
RodColeman 0:0791c1fece8e 666 }
RodColeman 0:0791c1fece8e 667
RodColeman 0:0791c1fece8e 668 case DNS_STATE_ASKING: {
RodColeman 0:0791c1fece8e 669 if (--pEntry->tmr == 0) {
RodColeman 0:0791c1fece8e 670 if (++pEntry->retries == DNS_MAX_RETRIES) {
RodColeman 0:0791c1fece8e 671 if ((pEntry->numdns+1<DNS_MAX_SERVERS) && (dns_servers[pEntry->numdns+1].addr!=0)) {
RodColeman 0:0791c1fece8e 672 /* change of server */
RodColeman 0:0791c1fece8e 673 pEntry->numdns++;
RodColeman 0:0791c1fece8e 674 pEntry->tmr = 1;
RodColeman 0:0791c1fece8e 675 pEntry->retries = 0;
RodColeman 0:0791c1fece8e 676 break;
RodColeman 0:0791c1fece8e 677 } else {
RodColeman 0:0791c1fece8e 678 LWIP_DEBUGF(DNS_DEBUG, ("dns_check_entry: \"%s\": timeout\n", pEntry->name));
RodColeman 0:0791c1fece8e 679 /* call specified callback function if provided */
RodColeman 0:0791c1fece8e 680 if (pEntry->found)
RodColeman 0:0791c1fece8e 681 (*pEntry->found)(pEntry->name, NULL, pEntry->arg);
RodColeman 0:0791c1fece8e 682 /* flush this entry */
RodColeman 0:0791c1fece8e 683 pEntry->state = DNS_STATE_UNUSED;
RodColeman 0:0791c1fece8e 684 pEntry->found = NULL;
RodColeman 0:0791c1fece8e 685 break;
RodColeman 0:0791c1fece8e 686 }
RodColeman 0:0791c1fece8e 687 }
RodColeman 0:0791c1fece8e 688
RodColeman 0:0791c1fece8e 689 /* wait longer for the next retry */
RodColeman 0:0791c1fece8e 690 pEntry->tmr = pEntry->retries;
RodColeman 0:0791c1fece8e 691
RodColeman 0:0791c1fece8e 692 /* send DNS packet for this entry */
RodColeman 0:0791c1fece8e 693 dns_send(pEntry->numdns, pEntry->name, i);
RodColeman 0:0791c1fece8e 694 }
RodColeman 0:0791c1fece8e 695 break;
RodColeman 0:0791c1fece8e 696 }
RodColeman 0:0791c1fece8e 697
RodColeman 0:0791c1fece8e 698 case DNS_STATE_DONE: {
RodColeman 0:0791c1fece8e 699 /* if the time to live is nul */
RodColeman 0:0791c1fece8e 700 if (--pEntry->ttl == 0) {
RodColeman 0:0791c1fece8e 701 LWIP_DEBUGF(DNS_DEBUG, ("dns_check_entry: \"%s\": flush\n", pEntry->name));
RodColeman 0:0791c1fece8e 702 /* flush this entry */
RodColeman 0:0791c1fece8e 703 pEntry->state = DNS_STATE_UNUSED;
RodColeman 0:0791c1fece8e 704 pEntry->found = NULL;
RodColeman 0:0791c1fece8e 705 }
RodColeman 0:0791c1fece8e 706 break;
RodColeman 0:0791c1fece8e 707 }
RodColeman 0:0791c1fece8e 708 case DNS_STATE_UNUSED:
RodColeman 0:0791c1fece8e 709 /* nothing to do */
RodColeman 0:0791c1fece8e 710 break;
RodColeman 0:0791c1fece8e 711 default:
RodColeman 0:0791c1fece8e 712 LWIP_ASSERT("unknown dns_table entry state:", 0);
RodColeman 0:0791c1fece8e 713 break;
RodColeman 0:0791c1fece8e 714 }
RodColeman 0:0791c1fece8e 715 }
RodColeman 0:0791c1fece8e 716
RodColeman 0:0791c1fece8e 717 /**
RodColeman 0:0791c1fece8e 718 * Call dns_check_entry for each entry in dns_table - check all entries.
RodColeman 0:0791c1fece8e 719 */
RodColeman 0:0791c1fece8e 720 static void
RodColeman 0:0791c1fece8e 721 dns_check_entries(void)
RodColeman 0:0791c1fece8e 722 {
RodColeman 0:0791c1fece8e 723 u8_t i;
RodColeman 0:0791c1fece8e 724
RodColeman 0:0791c1fece8e 725 for (i = 0; i < DNS_TABLE_SIZE; ++i) {
RodColeman 0:0791c1fece8e 726 dns_check_entry(i);
RodColeman 0:0791c1fece8e 727 }
RodColeman 0:0791c1fece8e 728 }
RodColeman 0:0791c1fece8e 729
RodColeman 0:0791c1fece8e 730 /**
RodColeman 0:0791c1fece8e 731 * Receive input function for DNS response packets arriving for the dns UDP pcb.
RodColeman 0:0791c1fece8e 732 *
RodColeman 0:0791c1fece8e 733 * @params see udp.h
RodColeman 0:0791c1fece8e 734 */
RodColeman 0:0791c1fece8e 735 static void
RodColeman 0:0791c1fece8e 736 dns_recv(void *arg, struct udp_pcb *pcb, struct pbuf *p, struct ip_addr *addr, u16_t port)
RodColeman 0:0791c1fece8e 737 {
RodColeman 0:0791c1fece8e 738 u8_t i;
RodColeman 0:0791c1fece8e 739 char *pHostname;
RodColeman 0:0791c1fece8e 740 struct dns_hdr *hdr;
RodColeman 0:0791c1fece8e 741 struct dns_answer ans;
RodColeman 0:0791c1fece8e 742 struct dns_table_entry *pEntry;
RodColeman 0:0791c1fece8e 743 u8_t nquestions, nanswers;
RodColeman 0:0791c1fece8e 744 #if (DNS_USES_STATIC_BUF == 0)
RodColeman 0:0791c1fece8e 745 u8_t dns_payload[DNS_MSG_SIZE];
RodColeman 0:0791c1fece8e 746 #endif /* (DNS_USES_STATIC_BUF == 0) */
RodColeman 0:0791c1fece8e 747 #if (DNS_USES_STATIC_BUF == 2)
RodColeman 0:0791c1fece8e 748 u8_t* dns_payload;
RodColeman 0:0791c1fece8e 749 #endif /* (DNS_USES_STATIC_BUF == 2) */
RodColeman 0:0791c1fece8e 750
RodColeman 0:0791c1fece8e 751 LWIP_UNUSED_ARG(arg);
RodColeman 0:0791c1fece8e 752 LWIP_UNUSED_ARG(pcb);
RodColeman 0:0791c1fece8e 753 LWIP_UNUSED_ARG(addr);
RodColeman 0:0791c1fece8e 754 LWIP_UNUSED_ARG(port);
RodColeman 0:0791c1fece8e 755
RodColeman 0:0791c1fece8e 756 /* is the dns message too big ? */
RodColeman 0:0791c1fece8e 757 if (p->tot_len > DNS_MSG_SIZE) {
RodColeman 0:0791c1fece8e 758 LWIP_DEBUGF(DNS_DEBUG, ("dns_recv: pbuf too big\n"));
RodColeman 0:0791c1fece8e 759 /* free pbuf and return */
RodColeman 0:0791c1fece8e 760 goto memerr1;
RodColeman 0:0791c1fece8e 761 }
RodColeman 0:0791c1fece8e 762
RodColeman 0:0791c1fece8e 763 /* is the dns message big enough ? */
RodColeman 0:0791c1fece8e 764 if (p->tot_len < (SIZEOF_DNS_HDR + SIZEOF_DNS_QUERY + SIZEOF_DNS_ANSWER)) {
RodColeman 0:0791c1fece8e 765 LWIP_DEBUGF(DNS_DEBUG, ("dns_recv: pbuf too small\n"));
RodColeman 0:0791c1fece8e 766 /* free pbuf and return */
RodColeman 0:0791c1fece8e 767 goto memerr1;
RodColeman 0:0791c1fece8e 768 }
RodColeman 0:0791c1fece8e 769
RodColeman 0:0791c1fece8e 770 #if (DNS_USES_STATIC_BUF == 2)
RodColeman 0:0791c1fece8e 771 dns_payload = mem_malloc(p->tot_len);
RodColeman 0:0791c1fece8e 772 if (dns_payload == NULL) {
RodColeman 0:0791c1fece8e 773 LWIP_DEBUGF(DNS_DEBUG, ("dns_recv: mem_malloc error\n"));
RodColeman 0:0791c1fece8e 774 /* free pbuf and return */
RodColeman 0:0791c1fece8e 775 goto memerr1;
RodColeman 0:0791c1fece8e 776 }
RodColeman 0:0791c1fece8e 777 #endif /* (DNS_USES_STATIC_BUF == 2) */
RodColeman 0:0791c1fece8e 778
RodColeman 0:0791c1fece8e 779 /* copy dns payload inside static buffer for processing */
RodColeman 0:0791c1fece8e 780 if (pbuf_copy_partial(p, dns_payload, p->tot_len, 0) == p->tot_len) {
RodColeman 0:0791c1fece8e 781 /* The ID in the DNS header should be our entry into the name table. */
RodColeman 0:0791c1fece8e 782 hdr = (struct dns_hdr*)dns_payload;
RodColeman 0:0791c1fece8e 783 i = htons(hdr->id);
RodColeman 0:0791c1fece8e 784 if (i < DNS_TABLE_SIZE) {
RodColeman 0:0791c1fece8e 785 pEntry = &dns_table[i];
RodColeman 0:0791c1fece8e 786 if(pEntry->state == DNS_STATE_ASKING) {
RodColeman 0:0791c1fece8e 787 /* This entry is now completed. */
RodColeman 0:0791c1fece8e 788 pEntry->state = DNS_STATE_DONE;
RodColeman 0:0791c1fece8e 789 pEntry->err = hdr->flags2 & DNS_FLAG2_ERR_MASK;
RodColeman 0:0791c1fece8e 790
RodColeman 0:0791c1fece8e 791 /* We only care about the question(s) and the answers. The authrr
RodColeman 0:0791c1fece8e 792 and the extrarr are simply discarded. */
RodColeman 0:0791c1fece8e 793 nquestions = htons(hdr->numquestions);
RodColeman 0:0791c1fece8e 794 nanswers = htons(hdr->numanswers);
RodColeman 0:0791c1fece8e 795
RodColeman 0:0791c1fece8e 796 /* Check for error. If so, call callback to inform. */
RodColeman 0:0791c1fece8e 797 if (((hdr->flags1 & DNS_FLAG1_RESPONSE) == 0) || (pEntry->err != 0) || (nquestions != 1)) {
RodColeman 0:0791c1fece8e 798 LWIP_DEBUGF(DNS_DEBUG, ("dns_recv: \"%s\": error in flags\n", pEntry->name));
RodColeman 0:0791c1fece8e 799 /* call callback to indicate error, clean up memory and return */
RodColeman 0:0791c1fece8e 800 goto responseerr;
RodColeman 0:0791c1fece8e 801 }
RodColeman 0:0791c1fece8e 802
RodColeman 0:0791c1fece8e 803 #if DNS_DOES_NAME_CHECK
RodColeman 0:0791c1fece8e 804 /* Check if the name in the "question" part match with the name in the entry. */
RodColeman 0:0791c1fece8e 805 if (dns_compare_name((unsigned char *)(pEntry->name), (unsigned char *)dns_payload + SIZEOF_DNS_HDR) != 0) {
RodColeman 0:0791c1fece8e 806 LWIP_DEBUGF(DNS_DEBUG, ("dns_recv: \"%s\": response not match to query\n", pEntry->name));
RodColeman 0:0791c1fece8e 807 /* call callback to indicate error, clean up memory and return */
RodColeman 0:0791c1fece8e 808 goto responseerr;
RodColeman 0:0791c1fece8e 809 }
RodColeman 0:0791c1fece8e 810 #endif /* DNS_DOES_NAME_CHECK */
RodColeman 0:0791c1fece8e 811
RodColeman 0:0791c1fece8e 812 /* Skip the name in the "question" part */
RodColeman 0:0791c1fece8e 813 pHostname = (char *) dns_parse_name((unsigned char *)dns_payload + SIZEOF_DNS_HDR) + SIZEOF_DNS_QUERY;
RodColeman 0:0791c1fece8e 814
RodColeman 0:0791c1fece8e 815 while(nanswers > 0) {
RodColeman 0:0791c1fece8e 816 /* skip answer resource record's host name */
RodColeman 0:0791c1fece8e 817 pHostname = (char *) dns_parse_name((unsigned char *)pHostname);
RodColeman 0:0791c1fece8e 818
RodColeman 0:0791c1fece8e 819 /* Check for IP address type and Internet class. Others are discarded. */
RodColeman 0:0791c1fece8e 820 MEMCPY(&ans, pHostname, SIZEOF_DNS_ANSWER);
RodColeman 0:0791c1fece8e 821 if((ntohs(ans.type) == DNS_RRTYPE_A) && (ntohs(ans.class) == DNS_RRCLASS_IN) && (ntohs(ans.len) == sizeof(struct ip_addr)) ) {
RodColeman 0:0791c1fece8e 822 /* read the answer resource record's TTL, and maximize it if needed */
RodColeman 0:0791c1fece8e 823 pEntry->ttl = ntohl(ans.ttl);
RodColeman 0:0791c1fece8e 824 if (pEntry->ttl > DNS_MAX_TTL) {
RodColeman 0:0791c1fece8e 825 pEntry->ttl = DNS_MAX_TTL;
RodColeman 0:0791c1fece8e 826 }
RodColeman 0:0791c1fece8e 827 /* read the IP address after answer resource record's header */
RodColeman 0:0791c1fece8e 828 MEMCPY( &(pEntry->ipaddr), (pHostname+SIZEOF_DNS_ANSWER), sizeof(struct ip_addr));
RodColeman 0:0791c1fece8e 829 LWIP_DEBUGF(DNS_DEBUG, ("dns_recv: \"%s\": response = ", pEntry->name));
RodColeman 0:0791c1fece8e 830 ip_addr_debug_print(DNS_DEBUG, (&(pEntry->ipaddr)));
RodColeman 0:0791c1fece8e 831 LWIP_DEBUGF(DNS_DEBUG, ("\n"));
RodColeman 0:0791c1fece8e 832 /* call specified callback function if provided */
RodColeman 0:0791c1fece8e 833 if (pEntry->found) {
RodColeman 0:0791c1fece8e 834 (*pEntry->found)(pEntry->name, &pEntry->ipaddr, pEntry->arg);
RodColeman 0:0791c1fece8e 835 }
RodColeman 0:0791c1fece8e 836 /* deallocate memory and return */
RodColeman 0:0791c1fece8e 837 goto memerr2;
RodColeman 0:0791c1fece8e 838 } else {
RodColeman 0:0791c1fece8e 839 pHostname = pHostname + SIZEOF_DNS_ANSWER + htons(ans.len);
RodColeman 0:0791c1fece8e 840 }
RodColeman 0:0791c1fece8e 841 --nanswers;
RodColeman 0:0791c1fece8e 842 }
RodColeman 0:0791c1fece8e 843 LWIP_DEBUGF(DNS_DEBUG, ("dns_recv: \"%s\": error in response\n", pEntry->name));
RodColeman 0:0791c1fece8e 844 /* call callback to indicate error, clean up memory and return */
RodColeman 0:0791c1fece8e 845 goto responseerr;
RodColeman 0:0791c1fece8e 846 }
RodColeman 0:0791c1fece8e 847 }
RodColeman 0:0791c1fece8e 848 }
RodColeman 0:0791c1fece8e 849
RodColeman 0:0791c1fece8e 850 /* deallocate memory and return */
RodColeman 0:0791c1fece8e 851 goto memerr2;
RodColeman 0:0791c1fece8e 852
RodColeman 0:0791c1fece8e 853 responseerr:
RodColeman 0:0791c1fece8e 854 /* ERROR: call specified callback function with NULL as name to indicate an error */
RodColeman 0:0791c1fece8e 855 if (pEntry->found) {
RodColeman 0:0791c1fece8e 856 (*pEntry->found)(pEntry->name, NULL, pEntry->arg);
RodColeman 0:0791c1fece8e 857 }
RodColeman 0:0791c1fece8e 858 /* flush this entry */
RodColeman 0:0791c1fece8e 859 pEntry->state = DNS_STATE_UNUSED;
RodColeman 0:0791c1fece8e 860 pEntry->found = NULL;
RodColeman 0:0791c1fece8e 861
RodColeman 0:0791c1fece8e 862 memerr2:
RodColeman 0:0791c1fece8e 863 #if (DNS_USES_STATIC_BUF == 2)
RodColeman 0:0791c1fece8e 864 /* free dns buffer */
RodColeman 0:0791c1fece8e 865 mem_free(dns_payload);
RodColeman 0:0791c1fece8e 866 #endif /* (DNS_USES_STATIC_BUF == 2) */
RodColeman 0:0791c1fece8e 867
RodColeman 0:0791c1fece8e 868 memerr1:
RodColeman 0:0791c1fece8e 869 /* free pbuf */
RodColeman 0:0791c1fece8e 870 pbuf_free(p);
RodColeman 0:0791c1fece8e 871 return;
RodColeman 0:0791c1fece8e 872 }
RodColeman 0:0791c1fece8e 873
RodColeman 0:0791c1fece8e 874 /**
RodColeman 0:0791c1fece8e 875 * Queues a new hostname to resolve and sends out a DNS query for that hostname
RodColeman 0:0791c1fece8e 876 *
RodColeman 0:0791c1fece8e 877 * @param name the hostname that is to be queried
RodColeman 0:0791c1fece8e 878 * @param found a callback founction to be called on success, failure or timeout
RodColeman 0:0791c1fece8e 879 * @param callback_arg argument to pass to the callback function
RodColeman 0:0791c1fece8e 880 * @return @return a err_t return code.
RodColeman 0:0791c1fece8e 881 */
RodColeman 0:0791c1fece8e 882 static err_t
RodColeman 0:0791c1fece8e 883 dns_enqueue(const char *name, dns_found_callback found, void *callback_arg)
RodColeman 0:0791c1fece8e 884 {
RodColeman 0:0791c1fece8e 885 u8_t i;
RodColeman 0:0791c1fece8e 886 u8_t lseq, lseqi;
RodColeman 0:0791c1fece8e 887 struct dns_table_entry *pEntry = NULL;
RodColeman 0:0791c1fece8e 888
RodColeman 0:0791c1fece8e 889 /* search an unused entry, or the oldest one */
RodColeman 0:0791c1fece8e 890 lseq = lseqi = 0;
RodColeman 0:0791c1fece8e 891 for (i = 0; i < DNS_TABLE_SIZE; ++i) {
RodColeman 0:0791c1fece8e 892 pEntry = &dns_table[i];
RodColeman 0:0791c1fece8e 893 /* is it an unused entry ? */
RodColeman 0:0791c1fece8e 894 if (pEntry->state == DNS_STATE_UNUSED)
RodColeman 0:0791c1fece8e 895 break;
RodColeman 0:0791c1fece8e 896
RodColeman 0:0791c1fece8e 897 /* check if this is the oldest completed entry */
RodColeman 0:0791c1fece8e 898 if (pEntry->state == DNS_STATE_DONE) {
RodColeman 0:0791c1fece8e 899 if ((dns_seqno - pEntry->seqno) > lseq) {
RodColeman 0:0791c1fece8e 900 lseq = dns_seqno - pEntry->seqno;
RodColeman 0:0791c1fece8e 901 lseqi = i;
RodColeman 0:0791c1fece8e 902 }
RodColeman 0:0791c1fece8e 903 }
RodColeman 0:0791c1fece8e 904 }
RodColeman 0:0791c1fece8e 905
RodColeman 0:0791c1fece8e 906 /* if we don't have found an unused entry, use the oldest completed one */
RodColeman 0:0791c1fece8e 907 if (i == DNS_TABLE_SIZE) {
RodColeman 0:0791c1fece8e 908 if ((lseqi >= DNS_TABLE_SIZE) || (dns_table[lseqi].state != DNS_STATE_DONE)) {
RodColeman 0:0791c1fece8e 909 /* no entry can't be used now, table is full */
RodColeman 0:0791c1fece8e 910 LWIP_DEBUGF(DNS_DEBUG, ("dns_enqueue: \"%s\": DNS entries table is full\n", name));
RodColeman 0:0791c1fece8e 911 return ERR_MEM;
RodColeman 0:0791c1fece8e 912 } else {
RodColeman 0:0791c1fece8e 913 /* use the oldest completed one */
RodColeman 0:0791c1fece8e 914 i = lseqi;
RodColeman 0:0791c1fece8e 915 pEntry = &dns_table[i];
RodColeman 0:0791c1fece8e 916 }
RodColeman 0:0791c1fece8e 917 }
RodColeman 0:0791c1fece8e 918
RodColeman 0:0791c1fece8e 919 /* use this entry */
RodColeman 0:0791c1fece8e 920 LWIP_DEBUGF(DNS_DEBUG, ("dns_enqueue: \"%s\": use DNS entry %"U16_F"\n", name, (u16_t)(i)));
RodColeman 0:0791c1fece8e 921
RodColeman 0:0791c1fece8e 922 /* fill the entry */
RodColeman 0:0791c1fece8e 923 pEntry->state = DNS_STATE_NEW;
RodColeman 0:0791c1fece8e 924 pEntry->seqno = dns_seqno++;
RodColeman 0:0791c1fece8e 925 pEntry->found = found;
RodColeman 0:0791c1fece8e 926 pEntry->arg = callback_arg;
RodColeman 0:0791c1fece8e 927 strcpy(pEntry->name, name);
RodColeman 0:0791c1fece8e 928
RodColeman 0:0791c1fece8e 929 /* force to send query without waiting timer */
RodColeman 0:0791c1fece8e 930 dns_check_entry(i);
RodColeman 0:0791c1fece8e 931
RodColeman 0:0791c1fece8e 932 /* dns query is enqueued */
RodColeman 0:0791c1fece8e 933 return ERR_INPROGRESS;
RodColeman 0:0791c1fece8e 934 }
RodColeman 0:0791c1fece8e 935
RodColeman 0:0791c1fece8e 936 /**
RodColeman 0:0791c1fece8e 937 * Resolve a hostname (string) into an IP address.
RodColeman 0:0791c1fece8e 938 * NON-BLOCKING callback version for use with raw API!!!
RodColeman 0:0791c1fece8e 939 *
RodColeman 0:0791c1fece8e 940 * Returns immediately with one of err_t return codes:
RodColeman 0:0791c1fece8e 941 * - ERR_OK if hostname is a valid IP address string or the host
RodColeman 0:0791c1fece8e 942 * name is already in the local names table.
RodColeman 0:0791c1fece8e 943 * - ERR_INPROGRESS enqueue a request to be sent to the DNS server
RodColeman 0:0791c1fece8e 944 * for resolution if no errors are present.
RodColeman 0:0791c1fece8e 945 *
RodColeman 0:0791c1fece8e 946 * @param hostname the hostname that is to be queried
RodColeman 0:0791c1fece8e 947 * @param addr pointer to a struct ip_addr where to store the address if it is already
RodColeman 0:0791c1fece8e 948 * cached in the dns_table (only valid if ERR_OK is returned!)
RodColeman 0:0791c1fece8e 949 * @param found a callback function to be called on success, failure or timeout (only if
RodColeman 0:0791c1fece8e 950 * ERR_INPROGRESS is returned!)
RodColeman 0:0791c1fece8e 951 * @param callback_arg argument to pass to the callback function
RodColeman 0:0791c1fece8e 952 * @return a err_t return code.
RodColeman 0:0791c1fece8e 953 */
RodColeman 0:0791c1fece8e 954 err_t
RodColeman 0:0791c1fece8e 955 dns_gethostbyname(const char *hostname, struct ip_addr *addr, dns_found_callback found,
RodColeman 0:0791c1fece8e 956 void *callback_arg)
RodColeman 0:0791c1fece8e 957 {
RodColeman 0:0791c1fece8e 958 /* not initialized or no valid server yet, or invalid addr pointer
RodColeman 0:0791c1fece8e 959 * or invalid hostname or invalid hostname length */
RodColeman 0:0791c1fece8e 960 if ((dns_pcb == NULL) || (addr == NULL) ||
RodColeman 0:0791c1fece8e 961 (!hostname) || (!hostname[0]) ||
RodColeman 0:0791c1fece8e 962 (strlen(hostname) >= DNS_MAX_NAME_LENGTH)) {
RodColeman 0:0791c1fece8e 963 return ERR_VAL;
RodColeman 0:0791c1fece8e 964 }
RodColeman 0:0791c1fece8e 965
RodColeman 0:0791c1fece8e 966 #if LWIP_HAVE_LOOPIF
RodColeman 0:0791c1fece8e 967 if (strcmp(hostname,"localhost")==0) {
RodColeman 0:0791c1fece8e 968 addr->addr = htonl(INADDR_LOOPBACK);
RodColeman 0:0791c1fece8e 969 return ERR_OK;
RodColeman 0:0791c1fece8e 970 }
RodColeman 0:0791c1fece8e 971 #endif /* LWIP_HAVE_LOOPIF */
RodColeman 0:0791c1fece8e 972
RodColeman 0:0791c1fece8e 973 /* host name already in octet notation? set ip addr and return ERR_OK
RodColeman 0:0791c1fece8e 974 * already have this address cached? */
RodColeman 0:0791c1fece8e 975 if (((addr->addr = inet_addr(hostname)) != INADDR_NONE) ||
RodColeman 0:0791c1fece8e 976 ((addr->addr = dns_lookup(hostname)) != INADDR_NONE)) {
RodColeman 0:0791c1fece8e 977 return ERR_OK;
RodColeman 0:0791c1fece8e 978 }
RodColeman 0:0791c1fece8e 979
RodColeman 0:0791c1fece8e 980 /* queue query with specified callback */
RodColeman 0:0791c1fece8e 981 return dns_enqueue(hostname, found, callback_arg);
RodColeman 0:0791c1fece8e 982 }
RodColeman 0:0791c1fece8e 983
RodColeman 0:0791c1fece8e 984 #endif /* LWIP_DNS */