David Smart / lwip

minor derivative to reduce compiler warnings and tag read-only parameters as const.

Dependents:   EthernetInterface

Fork of lwip by mbed official

core/dns.c@21:d78ed585db09, 2018-06-10 (annotated)

Committer:
WiredHome
Date:
Sun Jun 10 22:17:20 2018 +0000
Revision:
21:d78ed585db09
Parent:
20:52b94de224f0 
revise some error returns for unique < 0 numbers

Who changed what in which revision?

UserRevisionLine numberNew contents of line
mbed_official 0:51ac1d130fd4 1 /**
mbed_official 0:51ac1d130fd4 2 * @file
mbed_official 0:51ac1d130fd4 3 * DNS - host name to IP address resolver.
mbed_official 0:51ac1d130fd4 4 *
mbed_official 0:51ac1d130fd4 5 */
mbed_official 0:51ac1d130fd4 6
mbed_official 0:51ac1d130fd4 7 /**
mbed_official 0:51ac1d130fd4 8
mbed_official 0:51ac1d130fd4 9 * This file implements a DNS host name to IP address resolver.
mbed_official 0:51ac1d130fd4 10
mbed_official 0:51ac1d130fd4 11 * Port to lwIP from uIP
mbed_official 0:51ac1d130fd4 12 * by Jim Pettinato April 2007
mbed_official 0:51ac1d130fd4 13
mbed_official 0:51ac1d130fd4 14 * uIP version Copyright (c) 2002-2003, Adam Dunkels.
mbed_official 0:51ac1d130fd4 15 * All rights reserved.
mbed_official 0:51ac1d130fd4 16 *
mbed_official 0:51ac1d130fd4 17 * Redistribution and use in source and binary forms, with or without
mbed_official 0:51ac1d130fd4 18 * modification, are permitted provided that the following conditions
mbed_official 0:51ac1d130fd4 19 * are met:
mbed_official 0:51ac1d130fd4 20 * 1. Redistributions of source code must retain the above copyright
mbed_official 0:51ac1d130fd4 21 * notice, this list of conditions and the following disclaimer.
mbed_official 0:51ac1d130fd4 22 * 2. Redistributions in binary form must reproduce the above copyright
mbed_official 0:51ac1d130fd4 23 * notice, this list of conditions and the following disclaimer in the
mbed_official 0:51ac1d130fd4 24 * documentation and/or other materials provided with the distribution.
mbed_official 0:51ac1d130fd4 25 * 3. The name of the author may not be used to endorse or promote
mbed_official 0:51ac1d130fd4 26 * products derived from this software without specific prior
mbed_official 0:51ac1d130fd4 27 * written permission.
mbed_official 0:51ac1d130fd4 28 *
mbed_official 0:51ac1d130fd4 29 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
mbed_official 0:51ac1d130fd4 30 * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
mbed_official 0:51ac1d130fd4 31 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
mbed_official 0:51ac1d130fd4 32 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
mbed_official 0:51ac1d130fd4 33 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
mbed_official 0:51ac1d130fd4 34 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
mbed_official 0:51ac1d130fd4 35 * GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
mbed_official 0:51ac1d130fd4 36 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
mbed_official 0:51ac1d130fd4 37 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
mbed_official 0:51ac1d130fd4 38 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
mbed_official 0:51ac1d130fd4 39 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
mbed_official 0:51ac1d130fd4 40 *
mbed_official 0:51ac1d130fd4 41 *
mbed_official 0:51ac1d130fd4 42 * DNS.C
mbed_official 0:51ac1d130fd4 43 *
mbed_official 0:51ac1d130fd4 44 * The lwIP DNS resolver functions are used to lookup a host name and
mbed_official 0:51ac1d130fd4 45 * map it to a numerical IP address. It maintains a list of resolved
mbed_official 0:51ac1d130fd4 46 * hostnames that can be queried with the dns_lookup() function.
mbed_official 0:51ac1d130fd4 47 * New hostnames can be resolved using the dns_query() function.
mbed_official 0:51ac1d130fd4 48 *
mbed_official 0:51ac1d130fd4 49 * The lwIP version of the resolver also adds a non-blocking version of
mbed_official 0:51ac1d130fd4 50 * gethostbyname() that will work with a raw API application. This function
mbed_official 0:51ac1d130fd4 51 * checks for an IP address string first and converts it if it is valid.
mbed_official 0:51ac1d130fd4 52 * gethostbyname() then does a dns_lookup() to see if the name is
mbed_official 0:51ac1d130fd4 53 * already in the table. If so, the IP is returned. If not, a query is
mbed_official 0:51ac1d130fd4 54 * issued and the function returns with a ERR_INPROGRESS status. The app
mbed_official 0:51ac1d130fd4 55 * using the dns client must then go into a waiting state.
mbed_official 0:51ac1d130fd4 56 *
mbed_official 0:51ac1d130fd4 57 * Once a hostname has been resolved (or found to be non-existent),
mbed_official 0:51ac1d130fd4 58 * the resolver code calls a specified callback function (which
mbed_official 0:51ac1d130fd4 59 * must be implemented by the module that uses the resolver).
mbed_official 0:51ac1d130fd4 60 */
mbed_official 0:51ac1d130fd4 61
mbed_official 0:51ac1d130fd4 62 /*-----------------------------------------------------------------------------
mbed_official 0:51ac1d130fd4 63 * RFC 1035 - Domain names - implementation and specification
mbed_official 0:51ac1d130fd4 64 * RFC 2181 - Clarifications to the DNS Specification
mbed_official 0:51ac1d130fd4 65 *----------------------------------------------------------------------------*/
mbed_official 0:51ac1d130fd4 66
mbed_official 0:51ac1d130fd4 67 /** @todo: define good default values (rfc compliance) */
mbed_official 0:51ac1d130fd4 68 /** @todo: improve answer parsing, more checkings... */
mbed_official 0:51ac1d130fd4 69 /** @todo: check RFC1035 - 7.3. Processing responses */
mbed_official 0:51ac1d130fd4 70
mbed_official 0:51ac1d130fd4 71 /*-----------------------------------------------------------------------------
mbed_official 0:51ac1d130fd4 72 * Includes
mbed_official 0:51ac1d130fd4 73 *----------------------------------------------------------------------------*/
mbed_official 0:51ac1d130fd4 74
mbed_official 0:51ac1d130fd4 75 #include "lwip/opt.h"
mbed_official 0:51ac1d130fd4 76
mbed_official 0:51ac1d130fd4 77 #if LWIP_DNS /* don't build if not configured for use in lwipopts.h */
mbed_official 0:51ac1d130fd4 78
mbed_official 0:51ac1d130fd4 79 #include "lwip/udp.h"
mbed_official 0:51ac1d130fd4 80 #include "lwip/mem.h"
mbed_official 0:51ac1d130fd4 81 #include "lwip/memp.h"
mbed_official 0:51ac1d130fd4 82 #include "lwip/dns.h"
mbed_official 0:51ac1d130fd4 83
mbed_official 0:51ac1d130fd4 84 #include <string.h>
mbed_official 0:51ac1d130fd4 85
mbed_official 0:51ac1d130fd4 86 /** DNS server IP address */
mbed_official 0:51ac1d130fd4 87 #ifndef DNS_SERVER_ADDRESS
mbed_official 0:51ac1d130fd4 88 #define DNS_SERVER_ADDRESS(ipaddr) (ip4_addr_set_u32(ipaddr, ipaddr_addr("208.67.222.222"))) /* resolver1.opendns.com */
mbed_official 0:51ac1d130fd4 89 #endif
mbed_official 0:51ac1d130fd4 90
mbed_official 0:51ac1d130fd4 91 /** DNS server port address */
mbed_official 0:51ac1d130fd4 92 #ifndef DNS_SERVER_PORT
mbed_official 0:51ac1d130fd4 93 #define DNS_SERVER_PORT 53
mbed_official 0:51ac1d130fd4 94 #endif
mbed_official 0:51ac1d130fd4 95
mbed_official 0:51ac1d130fd4 96 /** DNS maximum number of retries when asking for a name, before "timeout". */
mbed_official 0:51ac1d130fd4 97 #ifndef DNS_MAX_RETRIES
mbed_official 0:51ac1d130fd4 98 #define DNS_MAX_RETRIES 4
mbed_official 0:51ac1d130fd4 99 #endif
mbed_official 0:51ac1d130fd4 100
mbed_official 0:51ac1d130fd4 101 /** DNS resource record max. TTL (one week as default) */
mbed_official 0:51ac1d130fd4 102 #ifndef DNS_MAX_TTL
mbed_official 0:51ac1d130fd4 103 #define DNS_MAX_TTL 604800
mbed_official 0:51ac1d130fd4 104 #endif
mbed_official 0:51ac1d130fd4 105
mbed_official 0:51ac1d130fd4 106 /* DNS protocol flags */
mbed_official 0:51ac1d130fd4 107 #define DNS_FLAG1_RESPONSE 0x80
mbed_official 0:51ac1d130fd4 108 #define DNS_FLAG1_OPCODE_STATUS 0x10
mbed_official 0:51ac1d130fd4 109 #define DNS_FLAG1_OPCODE_INVERSE 0x08
mbed_official 0:51ac1d130fd4 110 #define DNS_FLAG1_OPCODE_STANDARD 0x00
mbed_official 0:51ac1d130fd4 111 #define DNS_FLAG1_AUTHORATIVE 0x04
mbed_official 0:51ac1d130fd4 112 #define DNS_FLAG1_TRUNC 0x02
mbed_official 0:51ac1d130fd4 113 #define DNS_FLAG1_RD 0x01
mbed_official 0:51ac1d130fd4 114 #define DNS_FLAG2_RA 0x80
mbed_official 0:51ac1d130fd4 115 #define DNS_FLAG2_ERR_MASK 0x0f
mbed_official 0:51ac1d130fd4 116 #define DNS_FLAG2_ERR_NONE 0x00
mbed_official 0:51ac1d130fd4 117 #define DNS_FLAG2_ERR_NAME 0x03
mbed_official 0:51ac1d130fd4 118
mbed_official 0:51ac1d130fd4 119 /* DNS protocol states */
mbed_official 0:51ac1d130fd4 120 #define DNS_STATE_UNUSED 0
mbed_official 0:51ac1d130fd4 121 #define DNS_STATE_NEW 1
mbed_official 0:51ac1d130fd4 122 #define DNS_STATE_ASKING 2
mbed_official 0:51ac1d130fd4 123 #define DNS_STATE_DONE 3
mbed_official 0:51ac1d130fd4 124
mbed_official 0:51ac1d130fd4 125 #ifdef PACK_STRUCT_USE_INCLUDES
mbed_official 0:51ac1d130fd4 126 # include "arch/bpstruct.h"
mbed_official 0:51ac1d130fd4 127 #endif
mbed_official 0:51ac1d130fd4 128 PACK_STRUCT_BEGIN
mbed_official 0:51ac1d130fd4 129 /** DNS message header */
mbed_official 0:51ac1d130fd4 130 struct dns_hdr {
mbed_official 0:51ac1d130fd4 131 PACK_STRUCT_FIELD(u16_t id);
mbed_official 0:51ac1d130fd4 132 PACK_STRUCT_FIELD(u8_t flags1);
mbed_official 0:51ac1d130fd4 133 PACK_STRUCT_FIELD(u8_t flags2);
mbed_official 0:51ac1d130fd4 134 PACK_STRUCT_FIELD(u16_t numquestions);
mbed_official 0:51ac1d130fd4 135 PACK_STRUCT_FIELD(u16_t numanswers);
mbed_official 0:51ac1d130fd4 136 PACK_STRUCT_FIELD(u16_t numauthrr);
mbed_official 0:51ac1d130fd4 137 PACK_STRUCT_FIELD(u16_t numextrarr);
mbed_official 0:51ac1d130fd4 138 } PACK_STRUCT_STRUCT;
mbed_official 0:51ac1d130fd4 139 PACK_STRUCT_END
mbed_official 0:51ac1d130fd4 140 #ifdef PACK_STRUCT_USE_INCLUDES
mbed_official 0:51ac1d130fd4 141 # include "arch/epstruct.h"
mbed_official 0:51ac1d130fd4 142 #endif
mbed_official 0:51ac1d130fd4 143 #define SIZEOF_DNS_HDR 12
mbed_official 0:51ac1d130fd4 144
mbed_official 0:51ac1d130fd4 145 /** DNS query message structure.
mbed_official 0:51ac1d130fd4 146 No packing needed: only used locally on the stack. */
mbed_official 0:51ac1d130fd4 147 struct dns_query {
mbed_official 0:51ac1d130fd4 148 /* DNS query record starts with either a domain name or a pointer
mbed_official 0:51ac1d130fd4 149 to a name already present somewhere in the packet. */
mbed_official 0:51ac1d130fd4 150 u16_t type;
mbed_official 0:51ac1d130fd4 151 u16_t cls;
mbed_official 0:51ac1d130fd4 152 };
mbed_official 0:51ac1d130fd4 153 #define SIZEOF_DNS_QUERY 4
mbed_official 0:51ac1d130fd4 154
mbed_official 0:51ac1d130fd4 155 /** DNS answer message structure.
mbed_official 0:51ac1d130fd4 156 No packing needed: only used locally on the stack. */
mbed_official 0:51ac1d130fd4 157 struct dns_answer {
mbed_official 0:51ac1d130fd4 158 /* DNS answer record starts with either a domain name or a pointer
mbed_official 0:51ac1d130fd4 159 to a name already present somewhere in the packet. */
mbed_official 0:51ac1d130fd4 160 u16_t type;
mbed_official 0:51ac1d130fd4 161 u16_t cls;
mbed_official 0:51ac1d130fd4 162 u32_t ttl;
mbed_official 0:51ac1d130fd4 163 u16_t len;
mbed_official 0:51ac1d130fd4 164 };
mbed_official 0:51ac1d130fd4 165 #define SIZEOF_DNS_ANSWER 10
mbed_official 0:51ac1d130fd4 166
mbed_official 0:51ac1d130fd4 167 /** DNS table entry */
mbed_official 0:51ac1d130fd4 168 struct dns_table_entry {
mbed_official 0:51ac1d130fd4 169 u8_t state;
mbed_official 0:51ac1d130fd4 170 u8_t numdns;
mbed_official 0:51ac1d130fd4 171 u8_t tmr;
mbed_official 0:51ac1d130fd4 172 u8_t retries;
mbed_official 0:51ac1d130fd4 173 u8_t seqno;
mbed_official 0:51ac1d130fd4 174 u8_t err;
mbed_official 0:51ac1d130fd4 175 u32_t ttl;
mbed_official 0:51ac1d130fd4 176 char name[DNS_MAX_NAME_LENGTH];
mbed_official 0:51ac1d130fd4 177 ip_addr_t ipaddr;
mbed_official 0:51ac1d130fd4 178 /* pointer to callback on DNS query done */
mbed_official 0:51ac1d130fd4 179 dns_found_callback found;
mbed_official 0:51ac1d130fd4 180 void *arg;
mbed_official 0:51ac1d130fd4 181 };
mbed_official 0:51ac1d130fd4 182
mbed_official 0:51ac1d130fd4 183 #if DNS_LOCAL_HOSTLIST
mbed_official 0:51ac1d130fd4 184
mbed_official 0:51ac1d130fd4 185 #if DNS_LOCAL_HOSTLIST_IS_DYNAMIC
mbed_official 0:51ac1d130fd4 186 /** Local host-list. For hostnames in this list, no
mbed_official 0:51ac1d130fd4 187 * external name resolution is performed */
mbed_official 0:51ac1d130fd4 188 static struct local_hostlist_entry *local_hostlist_dynamic;
mbed_official 0:51ac1d130fd4 189 #else /* DNS_LOCAL_HOSTLIST_IS_DYNAMIC */
mbed_official 0:51ac1d130fd4 190
mbed_official 0:51ac1d130fd4 191 /** Defining this allows the local_hostlist_static to be placed in a different
mbed_official 0:51ac1d130fd4 192 * linker section (e.g. FLASH) */
mbed_official 0:51ac1d130fd4 193 #ifndef DNS_LOCAL_HOSTLIST_STORAGE_PRE
mbed_official 0:51ac1d130fd4 194 #define DNS_LOCAL_HOSTLIST_STORAGE_PRE static
mbed_official 0:51ac1d130fd4 195 #endif /* DNS_LOCAL_HOSTLIST_STORAGE_PRE */
mbed_official 0:51ac1d130fd4 196 /** Defining this allows the local_hostlist_static to be placed in a different
mbed_official 0:51ac1d130fd4 197 * linker section (e.g. FLASH) */
mbed_official 0:51ac1d130fd4 198 #ifndef DNS_LOCAL_HOSTLIST_STORAGE_POST
mbed_official 0:51ac1d130fd4 199 #define DNS_LOCAL_HOSTLIST_STORAGE_POST
mbed_official 0:51ac1d130fd4 200 #endif /* DNS_LOCAL_HOSTLIST_STORAGE_POST */
mbed_official 0:51ac1d130fd4 201 DNS_LOCAL_HOSTLIST_STORAGE_PRE struct local_hostlist_entry local_hostlist_static[]
mbed_official 0:51ac1d130fd4 202 DNS_LOCAL_HOSTLIST_STORAGE_POST = DNS_LOCAL_HOSTLIST_INIT;
mbed_official 0:51ac1d130fd4 203
mbed_official 0:51ac1d130fd4 204 #endif /* DNS_LOCAL_HOSTLIST_IS_DYNAMIC */
mbed_official 0:51ac1d130fd4 205
mbed_official 0:51ac1d130fd4 206 static void dns_init_local();
mbed_official 0:51ac1d130fd4 207 #endif /* DNS_LOCAL_HOSTLIST */
mbed_official 0:51ac1d130fd4 208
mbed_official 0:51ac1d130fd4 209
mbed_official 0:51ac1d130fd4 210 /* forward declarations */
mbed_official 0:51ac1d130fd4 211 static void dns_recv(void *s, struct udp_pcb *pcb, struct pbuf *p, ip_addr_t *addr, u16_t port);
mbed_official 0:51ac1d130fd4 212 static void dns_check_entries(void);
mbed_official 0:51ac1d130fd4 213
mbed_official 0:51ac1d130fd4 214 /*-----------------------------------------------------------------------------
mbed_official 0:51ac1d130fd4 215 * Globales
mbed_official 0:51ac1d130fd4 216 *----------------------------------------------------------------------------*/
mbed_official 0:51ac1d130fd4 217
mbed_official 0:51ac1d130fd4 218 /* DNS variables */
mbed_official 0:51ac1d130fd4 219 static struct udp_pcb *dns_pcb;
mbed_official 0:51ac1d130fd4 220 static u8_t dns_seqno;
mbed_official 0:51ac1d130fd4 221 static struct dns_table_entry dns_table[DNS_TABLE_SIZE];
mbed_official 0:51ac1d130fd4 222 static ip_addr_t dns_servers[DNS_MAX_SERVERS];
mbed_official 0:51ac1d130fd4 223 /** Contiguous buffer for processing responses */
mbed_official 0:51ac1d130fd4 224 static u8_t dns_payload_buffer[LWIP_MEM_ALIGN_BUFFER(DNS_MSG_SIZE)];
mbed_official 0:51ac1d130fd4 225 static u8_t* dns_payload;
mbed_official 0:51ac1d130fd4 226
mbed_official 0:51ac1d130fd4 227 /**
mbed_official 0:51ac1d130fd4 228 * Initialize the resolver: set up the UDP pcb and configure the default server
mbed_official 0:51ac1d130fd4 229 * (DNS_SERVER_ADDRESS).
mbed_official 0:51ac1d130fd4 230 */
mbed_official 0:51ac1d130fd4 231 void
mbed_official 0:51ac1d130fd4 232 dns_init()
mbed_official 0:51ac1d130fd4 233 {
mbed_official 0:51ac1d130fd4 234 ip_addr_t dnsserver;
mbed_official 0:51ac1d130fd4 235
mbed_official 0:51ac1d130fd4 236 dns_payload = (u8_t *)LWIP_MEM_ALIGN(dns_payload_buffer);
mbed_official 0:51ac1d130fd4 237
mbed_official 0:51ac1d130fd4 238 /* initialize default DNS server address */
mbed_official 0:51ac1d130fd4 239 DNS_SERVER_ADDRESS(&dnsserver);
mbed_official 0:51ac1d130fd4 240
mbed_official 0:51ac1d130fd4 241 LWIP_DEBUGF(DNS_DEBUG, ("dns_init: initializing\n"));
mbed_official 0:51ac1d130fd4 242
mbed_official 0:51ac1d130fd4 243 /* if dns client not yet initialized... */
mbed_official 0:51ac1d130fd4 244 if (dns_pcb == NULL) {
mbed_official 0:51ac1d130fd4 245 dns_pcb = udp_new();
mbed_official 0:51ac1d130fd4 246
mbed_official 0:51ac1d130fd4 247 if (dns_pcb != NULL) {
mbed_official 0:51ac1d130fd4 248 /* initialize DNS table not needed (initialized to zero since it is a
mbed_official 0:51ac1d130fd4 249 * global variable) */
mbed_official 0:51ac1d130fd4 250 LWIP_ASSERT("For implicit initialization to work, DNS_STATE_UNUSED needs to be 0",
mbed_official 0:51ac1d130fd4 251 DNS_STATE_UNUSED == 0);
mbed_official 0:51ac1d130fd4 252
mbed_official 0:51ac1d130fd4 253 /* initialize DNS client */
mbed_official 0:51ac1d130fd4 254 udp_bind(dns_pcb, IP_ADDR_ANY, 0);
mbed_official 0:51ac1d130fd4 255 udp_recv(dns_pcb, dns_recv, NULL);
mbed_official 0:51ac1d130fd4 256
mbed_official 0:51ac1d130fd4 257 /* initialize default DNS primary server */
mbed_official 0:51ac1d130fd4 258 dns_setserver(0, &dnsserver);
mbed_official 0:51ac1d130fd4 259 }
mbed_official 0:51ac1d130fd4 260 }
mbed_official 0:51ac1d130fd4 261 #if DNS_LOCAL_HOSTLIST
mbed_official 0:51ac1d130fd4 262 dns_init_local();
mbed_official 0:51ac1d130fd4 263 #endif
mbed_official 0:51ac1d130fd4 264 }
mbed_official 0:51ac1d130fd4 265
mbed_official 0:51ac1d130fd4 266 /**
mbed_official 0:51ac1d130fd4 267 * Initialize one of the DNS servers.
mbed_official 0:51ac1d130fd4 268 *
mbed_official 0:51ac1d130fd4 269 * @param numdns the index of the DNS server to set must be < DNS_MAX_SERVERS
mbed_official 0:51ac1d130fd4 270 * @param dnsserver IP address of the DNS server to set
mbed_official 0:51ac1d130fd4 271 */
mbed_official 0:51ac1d130fd4 272 void
mbed_official 0:51ac1d130fd4 273 dns_setserver(u8_t numdns, ip_addr_t *dnsserver)
mbed_official 0:51ac1d130fd4 274 {
mbed_official 0:51ac1d130fd4 275 if ((numdns < DNS_MAX_SERVERS) && (dns_pcb != NULL) &&
mbed_official 0:51ac1d130fd4 276 (dnsserver != NULL) && !ip_addr_isany(dnsserver)) {
mbed_official 0:51ac1d130fd4 277 dns_servers[numdns] = (*dnsserver);
mbed_official 0:51ac1d130fd4 278 }
mbed_official 0:51ac1d130fd4 279 }
mbed_official 0:51ac1d130fd4 280
mbed_official 0:51ac1d130fd4 281 /**
mbed_official 0:51ac1d130fd4 282 * Obtain one of the currently configured DNS server.
mbed_official 0:51ac1d130fd4 283 *
mbed_official 0:51ac1d130fd4 284 * @param numdns the index of the DNS server
mbed_official 0:51ac1d130fd4 285 * @return IP address of the indexed DNS server or "ip_addr_any" if the DNS
mbed_official 0:51ac1d130fd4 286 * server has not been configured.
mbed_official 0:51ac1d130fd4 287 */
mbed_official 0:51ac1d130fd4 288 ip_addr_t
mbed_official 0:51ac1d130fd4 289 dns_getserver(u8_t numdns)
mbed_official 0:51ac1d130fd4 290 {
mbed_official 0:51ac1d130fd4 291 if (numdns < DNS_MAX_SERVERS) {
mbed_official 0:51ac1d130fd4 292 return dns_servers[numdns];
mbed_official 0:51ac1d130fd4 293 } else {
mbed_official 0:51ac1d130fd4 294 return *IP_ADDR_ANY;
mbed_official 0:51ac1d130fd4 295 }
mbed_official 0:51ac1d130fd4 296 }
mbed_official 0:51ac1d130fd4 297
mbed_official 0:51ac1d130fd4 298 /**
mbed_official 0:51ac1d130fd4 299 * The DNS resolver client timer - handle retries and timeouts and should
mbed_official 0:51ac1d130fd4 300 * be called every DNS_TMR_INTERVAL milliseconds (every second by default).
mbed_official 0:51ac1d130fd4 301 */
mbed_official 0:51ac1d130fd4 302 void
mbed_official 0:51ac1d130fd4 303 dns_tmr(void)
mbed_official 0:51ac1d130fd4 304 {
mbed_official 0:51ac1d130fd4 305 if (dns_pcb != NULL) {
mbed_official 0:51ac1d130fd4 306 LWIP_DEBUGF(DNS_DEBUG, ("dns_tmr: dns_check_entries\n"));
mbed_official 0:51ac1d130fd4 307 dns_check_entries();
mbed_official 0:51ac1d130fd4 308 }
mbed_official 0:51ac1d130fd4 309 }
mbed_official 0:51ac1d130fd4 310
mbed_official 0:51ac1d130fd4 311 #if DNS_LOCAL_HOSTLIST
mbed_official 0:51ac1d130fd4 312 static void
mbed_official 0:51ac1d130fd4 313 dns_init_local()
mbed_official 0:51ac1d130fd4 314 {
mbed_official 0:51ac1d130fd4 315 #if DNS_LOCAL_HOSTLIST_IS_DYNAMIC && defined(DNS_LOCAL_HOSTLIST_INIT)
mbed_official 0:51ac1d130fd4 316 int i;
mbed_official 0:51ac1d130fd4 317 struct local_hostlist_entry *entry;
mbed_official 0:51ac1d130fd4 318 /* Dynamic: copy entries from DNS_LOCAL_HOSTLIST_INIT to list */
mbed_official 0:51ac1d130fd4 319 struct local_hostlist_entry local_hostlist_init[] = DNS_LOCAL_HOSTLIST_INIT;
mbed_official 0:51ac1d130fd4 320 size_t namelen;
mbed_official 0:51ac1d130fd4 321 for (i = 0; i < sizeof(local_hostlist_init) / sizeof(struct local_hostlist_entry); i++) {
mbed_official 0:51ac1d130fd4 322 struct local_hostlist_entry *init_entry = &local_hostlist_init[i];
mbed_official 0:51ac1d130fd4 323 LWIP_ASSERT("invalid host name (NULL)", init_entry->name != NULL);
mbed_official 0:51ac1d130fd4 324 namelen = strlen(init_entry->name);
mbed_official 0:51ac1d130fd4 325 LWIP_ASSERT("namelen <= DNS_LOCAL_HOSTLIST_MAX_NAMELEN", namelen <= DNS_LOCAL_HOSTLIST_MAX_NAMELEN);
mbed_official 0:51ac1d130fd4 326 entry = (struct local_hostlist_entry *)memp_malloc(MEMP_LOCALHOSTLIST);
mbed_official 0:51ac1d130fd4 327 LWIP_ASSERT("mem-error in dns_init_local", entry != NULL);
mbed_official 0:51ac1d130fd4 328 if (entry != NULL) {
mbed_official 0:51ac1d130fd4 329 entry->name = (char*)entry + sizeof(struct local_hostlist_entry);
mbed_official 0:51ac1d130fd4 330 MEMCPY((char*)entry->name, init_entry->name, namelen);
mbed_official 0:51ac1d130fd4 331 ((char*)entry->name)[namelen] = 0;
mbed_official 0:51ac1d130fd4 332 entry->addr = init_entry->addr;
mbed_official 0:51ac1d130fd4 333 entry->next = local_hostlist_dynamic;
mbed_official 0:51ac1d130fd4 334 local_hostlist_dynamic = entry;
mbed_official 0:51ac1d130fd4 335 }
mbed_official 0:51ac1d130fd4 336 }
mbed_official 0:51ac1d130fd4 337 #endif /* DNS_LOCAL_HOSTLIST_IS_DYNAMIC && defined(DNS_LOCAL_HOSTLIST_INIT) */
mbed_official 0:51ac1d130fd4 338 }
mbed_official 0:51ac1d130fd4 339
mbed_official 0:51ac1d130fd4 340 /**
mbed_official 0:51ac1d130fd4 341 * Scans the local host-list for a hostname.
mbed_official 0:51ac1d130fd4 342 *
mbed_official 0:51ac1d130fd4 343 * @param hostname Hostname to look for in the local host-list
mbed_official 0:51ac1d130fd4 344 * @return The first IP address for the hostname in the local host-list or
mbed_official 0:51ac1d130fd4 345 * IPADDR_NONE if not found.
mbed_official 0:51ac1d130fd4 346 */
mbed_official 0:51ac1d130fd4 347 static u32_t
mbed_official 0:51ac1d130fd4 348 dns_lookup_local(const char *hostname)
mbed_official 0:51ac1d130fd4 349 {
mbed_official 0:51ac1d130fd4 350 #if DNS_LOCAL_HOSTLIST_IS_DYNAMIC
mbed_official 0:51ac1d130fd4 351 struct local_hostlist_entry *entry = local_hostlist_dynamic;
mbed_official 0:51ac1d130fd4 352 while(entry != NULL) {
mbed_official 0:51ac1d130fd4 353 if(strcmp(entry->name, hostname) == 0) {
mbed_official 0:51ac1d130fd4 354 return ip4_addr_get_u32(&entry->addr);
mbed_official 0:51ac1d130fd4 355 }
mbed_official 0:51ac1d130fd4 356 entry = entry->next;
mbed_official 0:51ac1d130fd4 357 }
mbed_official 0:51ac1d130fd4 358 #else /* DNS_LOCAL_HOSTLIST_IS_DYNAMIC */
mbed_official 0:51ac1d130fd4 359 int i;
mbed_official 0:51ac1d130fd4 360 for (i = 0; i < sizeof(local_hostlist_static) / sizeof(struct local_hostlist_entry); i++) {
mbed_official 0:51ac1d130fd4 361 if(strcmp(local_hostlist_static[i].name, hostname) == 0) {
mbed_official 0:51ac1d130fd4 362 return ip4_addr_get_u32(&local_hostlist_static[i].addr);
mbed_official 0:51ac1d130fd4 363 }
mbed_official 0:51ac1d130fd4 364 }
mbed_official 0:51ac1d130fd4 365 #endif /* DNS_LOCAL_HOSTLIST_IS_DYNAMIC */
mbed_official 0:51ac1d130fd4 366 return IPADDR_NONE;
mbed_official 0:51ac1d130fd4 367 }
mbed_official 0:51ac1d130fd4 368
mbed_official 0:51ac1d130fd4 369 #if DNS_LOCAL_HOSTLIST_IS_DYNAMIC
mbed_official 0:51ac1d130fd4 370 /** Remove all entries from the local host-list for a specific hostname
mbed_official 0:51ac1d130fd4 371 * and/or IP addess
mbed_official 0:51ac1d130fd4 372 *
mbed_official 0:51ac1d130fd4 373 * @param hostname hostname for which entries shall be removed from the local
mbed_official 0:51ac1d130fd4 374 * host-list
mbed_official 0:51ac1d130fd4 375 * @param addr address for which entries shall be removed from the local host-list
mbed_official 0:51ac1d130fd4 376 * @return the number of removed entries
mbed_official 0:51ac1d130fd4 377 */
mbed_official 0:51ac1d130fd4 378 int
mbed_official 0:51ac1d130fd4 379 dns_local_removehost(const char *hostname, const ip_addr_t *addr)
mbed_official 0:51ac1d130fd4 380 {
mbed_official 0:51ac1d130fd4 381 int removed = 0;
mbed_official 0:51ac1d130fd4 382 struct local_hostlist_entry *entry = local_hostlist_dynamic;
mbed_official 0:51ac1d130fd4 383 struct local_hostlist_entry *last_entry = NULL;
mbed_official 0:51ac1d130fd4 384 while (entry != NULL) {
mbed_official 0:51ac1d130fd4 385 if (((hostname == NULL) || !strcmp(entry->name, hostname)) &&
mbed_official 0:51ac1d130fd4 386 ((addr == NULL) || ip_addr_cmp(&entry->addr, addr))) {
mbed_official 0:51ac1d130fd4 387 struct local_hostlist_entry *free_entry;
mbed_official 0:51ac1d130fd4 388 if (last_entry != NULL) {
mbed_official 0:51ac1d130fd4 389 last_entry->next = entry->next;
mbed_official 0:51ac1d130fd4 390 } else {
mbed_official 0:51ac1d130fd4 391 local_hostlist_dynamic = entry->next;
mbed_official 0:51ac1d130fd4 392 }
mbed_official 0:51ac1d130fd4 393 free_entry = entry;
mbed_official 0:51ac1d130fd4 394 entry = entry->next;
mbed_official 0:51ac1d130fd4 395 memp_free(MEMP_LOCALHOSTLIST, free_entry);
mbed_official 0:51ac1d130fd4 396 removed++;
mbed_official 0:51ac1d130fd4 397 } else {
mbed_official 0:51ac1d130fd4 398 last_entry = entry;
mbed_official 0:51ac1d130fd4 399 entry = entry->next;
mbed_official 0:51ac1d130fd4 400 }
mbed_official 0:51ac1d130fd4 401 }
mbed_official 0:51ac1d130fd4 402 return removed;
mbed_official 0:51ac1d130fd4 403 }
mbed_official 0:51ac1d130fd4 404
mbed_official 0:51ac1d130fd4 405 /**
mbed_official 0:51ac1d130fd4 406 * Add a hostname/IP address pair to the local host-list.
mbed_official 0:51ac1d130fd4 407 * Duplicates are not checked.
mbed_official 0:51ac1d130fd4 408 *
mbed_official 0:51ac1d130fd4 409 * @param hostname hostname of the new entry
mbed_official 0:51ac1d130fd4 410 * @param addr IP address of the new entry
mbed_official 0:51ac1d130fd4 411 * @return ERR_OK if succeeded or ERR_MEM on memory error
mbed_official 0:51ac1d130fd4 412 */
mbed_official 0:51ac1d130fd4 413 err_t
mbed_official 0:51ac1d130fd4 414 dns_local_addhost(const char *hostname, const ip_addr_t *addr)
mbed_official 0:51ac1d130fd4 415 {
mbed_official 0:51ac1d130fd4 416 struct local_hostlist_entry *entry;
mbed_official 0:51ac1d130fd4 417 size_t namelen;
mbed_official 0:51ac1d130fd4 418 LWIP_ASSERT("invalid host name (NULL)", hostname != NULL);
mbed_official 0:51ac1d130fd4 419 namelen = strlen(hostname);
mbed_official 0:51ac1d130fd4 420 LWIP_ASSERT("namelen <= DNS_LOCAL_HOSTLIST_MAX_NAMELEN", namelen <= DNS_LOCAL_HOSTLIST_MAX_NAMELEN);
mbed_official 0:51ac1d130fd4 421 entry = (struct local_hostlist_entry *)memp_malloc(MEMP_LOCALHOSTLIST);
mbed_official 0:51ac1d130fd4 422 if (entry == NULL) {
mbed_official 0:51ac1d130fd4 423 return ERR_MEM;
mbed_official 0:51ac1d130fd4 424 }
mbed_official 0:51ac1d130fd4 425 entry->name = (char*)entry + sizeof(struct local_hostlist_entry);
mbed_official 0:51ac1d130fd4 426 MEMCPY((char*)entry->name, hostname, namelen);
mbed_official 0:51ac1d130fd4 427 ((char*)entry->name)[namelen] = 0;
mbed_official 0:51ac1d130fd4 428 ip_addr_copy(entry->addr, *addr);
mbed_official 0:51ac1d130fd4 429 entry->next = local_hostlist_dynamic;
mbed_official 0:51ac1d130fd4 430 local_hostlist_dynamic = entry;
mbed_official 0:51ac1d130fd4 431 return ERR_OK;
mbed_official 0:51ac1d130fd4 432 }
mbed_official 0:51ac1d130fd4 433 #endif /* DNS_LOCAL_HOSTLIST_IS_DYNAMIC*/
mbed_official 0:51ac1d130fd4 434 #endif /* DNS_LOCAL_HOSTLIST */
mbed_official 0:51ac1d130fd4 435
mbed_official 0:51ac1d130fd4 436 /**
mbed_official 0:51ac1d130fd4 437 * Look up a hostname in the array of known hostnames.
mbed_official 0:51ac1d130fd4 438 *
mbed_official 0:51ac1d130fd4 439 * @note This function only looks in the internal array of known
mbed_official 0:51ac1d130fd4 440 * hostnames, it does not send out a query for the hostname if none
mbed_official 0:51ac1d130fd4 441 * was found. The function dns_enqueue() can be used to send a query
mbed_official 0:51ac1d130fd4 442 * for a hostname.
mbed_official 0:51ac1d130fd4 443 *
mbed_official 0:51ac1d130fd4 444 * @param name the hostname to look up
mbed_official 0:51ac1d130fd4 445 * @return the hostname's IP address, as u32_t (instead of ip_addr_t to
mbed_official 0:51ac1d130fd4 446 * better check for failure: != IPADDR_NONE) or IPADDR_NONE if the hostname
mbed_official 0:51ac1d130fd4 447 * was not found in the cached dns_table.
mbed_official 0:51ac1d130fd4 448 */
mbed_official 0:51ac1d130fd4 449 static u32_t
mbed_official 0:51ac1d130fd4 450 dns_lookup(const char *name)
mbed_official 0:51ac1d130fd4 451 {
mbed_official 0:51ac1d130fd4 452 u8_t i;
mbed_official 0:51ac1d130fd4 453 #if DNS_LOCAL_HOSTLIST || defined(DNS_LOOKUP_LOCAL_EXTERN)
mbed_official 0:51ac1d130fd4 454 u32_t addr;
mbed_official 0:51ac1d130fd4 455 #endif /* DNS_LOCAL_HOSTLIST || defined(DNS_LOOKUP_LOCAL_EXTERN) */
mbed_official 0:51ac1d130fd4 456 #if DNS_LOCAL_HOSTLIST
mbed_official 0:51ac1d130fd4 457 if ((addr = dns_lookup_local(name)) != IPADDR_NONE) {
mbed_official 0:51ac1d130fd4 458 return addr;
mbed_official 0:51ac1d130fd4 459 }
mbed_official 0:51ac1d130fd4 460 #endif /* DNS_LOCAL_HOSTLIST */
mbed_official 0:51ac1d130fd4 461 #ifdef DNS_LOOKUP_LOCAL_EXTERN
mbed_official 0:51ac1d130fd4 462 if((addr = DNS_LOOKUP_LOCAL_EXTERN(name)) != IPADDR_NONE) {
mbed_official 0:51ac1d130fd4 463 return addr;
mbed_official 0:51ac1d130fd4 464 }
mbed_official 0:51ac1d130fd4 465 #endif /* DNS_LOOKUP_LOCAL_EXTERN */
mbed_official 0:51ac1d130fd4 466
mbed_official 0:51ac1d130fd4 467 /* Walk through name list, return entry if found. If not, return NULL. */
mbed_official 0:51ac1d130fd4 468 for (i = 0; i < DNS_TABLE_SIZE; ++i) {
mbed_official 0:51ac1d130fd4 469 if ((dns_table[i].state == DNS_STATE_DONE) &&
mbed_official 0:51ac1d130fd4 470 (strcmp(name, dns_table[i].name) == 0)) {
mbed_official 0:51ac1d130fd4 471 LWIP_DEBUGF(DNS_DEBUG, ("dns_lookup: \"%s\": found = ", name));
mbed_official 0:51ac1d130fd4 472 ip_addr_debug_print(DNS_DEBUG, &(dns_table[i].ipaddr));
mbed_official 0:51ac1d130fd4 473 LWIP_DEBUGF(DNS_DEBUG, ("\n"));
mbed_official 0:51ac1d130fd4 474 return ip4_addr_get_u32(&dns_table[i].ipaddr);
mbed_official 0:51ac1d130fd4 475 }
mbed_official 0:51ac1d130fd4 476 }
mbed_official 0:51ac1d130fd4 477
mbed_official 0:51ac1d130fd4 478 return IPADDR_NONE;
mbed_official 0:51ac1d130fd4 479 }
mbed_official 0:51ac1d130fd4 480
mbed_official 0:51ac1d130fd4 481 #if DNS_DOES_NAME_CHECK
mbed_official 0:51ac1d130fd4 482 /**
mbed_official 0:51ac1d130fd4 483 * Compare the "dotted" name "query" with the encoded name "response"
mbed_official 0:51ac1d130fd4 484 * to make sure an answer from the DNS server matches the current dns_table
mbed_official 0:51ac1d130fd4 485 * entry (otherwise, answers might arrive late for hostname not on the list
mbed_official 0:51ac1d130fd4 486 * any more).
mbed_official 0:51ac1d130fd4 487 *
mbed_official 0:51ac1d130fd4 488 * @param query hostname (not encoded) from the dns_table
mbed_official 0:51ac1d130fd4 489 * @param response encoded hostname in the DNS response
mbed_official 0:51ac1d130fd4 490 * @return 0: names equal; 1: names differ
mbed_official 0:51ac1d130fd4 491 */
mbed_official 0:51ac1d130fd4 492 static u8_t
mbed_official 0:51ac1d130fd4 493 dns_compare_name(unsigned char *query, unsigned char *response)
mbed_official 0:51ac1d130fd4 494 {
mbed_official 0:51ac1d130fd4 495 unsigned char n;
mbed_official 0:51ac1d130fd4 496
mbed_official 0:51ac1d130fd4 497 do {
mbed_official 0:51ac1d130fd4 498 n = *response++;
mbed_official 0:51ac1d130fd4 499 /** @see RFC 1035 - 4.1.4. Message compression */
mbed_official 0:51ac1d130fd4 500 if ((n & 0xc0) == 0xc0) {
mbed_official 0:51ac1d130fd4 501 /* Compressed name */
mbed_official 0:51ac1d130fd4 502 break;
mbed_official 0:51ac1d130fd4 503 } else {
mbed_official 0:51ac1d130fd4 504 /* Not compressed name */
mbed_official 0:51ac1d130fd4 505 while (n > 0) {
mbed_official 0:51ac1d130fd4 506 if ((*query) != (*response)) {
mbed_official 0:51ac1d130fd4 507 return 1;
mbed_official 0:51ac1d130fd4 508 }
mbed_official 0:51ac1d130fd4 509 ++response;
mbed_official 0:51ac1d130fd4 510 ++query;
mbed_official 0:51ac1d130fd4 511 --n;
mbed_official 0:51ac1d130fd4 512 };
mbed_official 0:51ac1d130fd4 513 ++query;
mbed_official 0:51ac1d130fd4 514 }
mbed_official 0:51ac1d130fd4 515 } while (*response != 0);
mbed_official 0:51ac1d130fd4 516
mbed_official 0:51ac1d130fd4 517 return 0;
mbed_official 0:51ac1d130fd4 518 }
mbed_official 0:51ac1d130fd4 519 #endif /* DNS_DOES_NAME_CHECK */
mbed_official 0:51ac1d130fd4 520
mbed_official 0:51ac1d130fd4 521 /**
mbed_official 0:51ac1d130fd4 522 * Walk through a compact encoded DNS name and return the end of the name.
mbed_official 0:51ac1d130fd4 523 *
mbed_official 0:51ac1d130fd4 524 * @param query encoded DNS name in the DNS server response
mbed_official 0:51ac1d130fd4 525 * @return end of the name
mbed_official 0:51ac1d130fd4 526 */
mbed_official 0:51ac1d130fd4 527 static unsigned char *
mbed_official 0:51ac1d130fd4 528 dns_parse_name(unsigned char *query)
mbed_official 0:51ac1d130fd4 529 {
mbed_official 0:51ac1d130fd4 530 unsigned char n;
mbed_official 0:51ac1d130fd4 531
mbed_official 0:51ac1d130fd4 532 do {
mbed_official 0:51ac1d130fd4 533 n = *query++;
mbed_official 0:51ac1d130fd4 534 /** @see RFC 1035 - 4.1.4. Message compression */
mbed_official 0:51ac1d130fd4 535 if ((n & 0xc0) == 0xc0) {
mbed_official 0:51ac1d130fd4 536 /* Compressed name */
mbed_official 0:51ac1d130fd4 537 break;
mbed_official 0:51ac1d130fd4 538 } else {
mbed_official 0:51ac1d130fd4 539 /* Not compressed name */
mbed_official 0:51ac1d130fd4 540 while (n > 0) {
mbed_official 0:51ac1d130fd4 541 ++query;
mbed_official 0:51ac1d130fd4 542 --n;
mbed_official 0:51ac1d130fd4 543 };
mbed_official 0:51ac1d130fd4 544 }
mbed_official 0:51ac1d130fd4 545 } while (*query != 0);
mbed_official 0:51ac1d130fd4 546
mbed_official 0:51ac1d130fd4 547 return query + 1;
mbed_official 0:51ac1d130fd4 548 }
mbed_official 0:51ac1d130fd4 549
mbed_official 0:51ac1d130fd4 550 /**
mbed_official 0:51ac1d130fd4 551 * Send a DNS query packet.
mbed_official 0:51ac1d130fd4 552 *
mbed_official 0:51ac1d130fd4 553 * @param numdns index of the DNS server in the dns_servers table
mbed_official 0:51ac1d130fd4 554 * @param name hostname to query
mbed_official 0:51ac1d130fd4 555 * @param id index of the hostname in dns_table, used as transaction ID in the
mbed_official 0:51ac1d130fd4 556 * DNS query packet
mbed_official 0:51ac1d130fd4 557 * @return ERR_OK if packet is sent; an err_t indicating the problem otherwise
mbed_official 0:51ac1d130fd4 558 */
mbed_official 0:51ac1d130fd4 559 static err_t
mbed_official 0:51ac1d130fd4 560 dns_send(u8_t numdns, const char* name, u8_t id)
mbed_official 0:51ac1d130fd4 561 {
mbed_official 0:51ac1d130fd4 562 err_t err;
mbed_official 0:51ac1d130fd4 563 struct dns_hdr *hdr;
mbed_official 0:51ac1d130fd4 564 struct dns_query qry;
mbed_official 0:51ac1d130fd4 565 struct pbuf *p;
mbed_official 0:51ac1d130fd4 566 char *query, *nptr;
mbed_official 0:51ac1d130fd4 567 const char *pHostname;
mbed_official 0:51ac1d130fd4 568 u8_t n;
mbed_official 0:51ac1d130fd4 569
WiredHome 20:52b94de224f0 570 memset(&qry, 0, sizeof(qry));
mbed_official 0:51ac1d130fd4 571 LWIP_DEBUGF(DNS_DEBUG, ("dns_send: dns_servers[%"U16_F"] \"%s\": request\n",
mbed_official 0:51ac1d130fd4 572 (u16_t)(numdns), name));
mbed_official 0:51ac1d130fd4 573 LWIP_ASSERT("dns server out of array", numdns < DNS_MAX_SERVERS);
mbed_official 0:51ac1d130fd4 574 LWIP_ASSERT("dns server has no IP address set", !ip_addr_isany(&dns_servers[numdns]));
mbed_official 0:51ac1d130fd4 575
mbed_official 0:51ac1d130fd4 576 /* if here, we have either a new query or a retry on a previous query to process */
mbed_official 0:51ac1d130fd4 577 p = pbuf_alloc(PBUF_TRANSPORT, SIZEOF_DNS_HDR + DNS_MAX_NAME_LENGTH +
mbed_official 0:51ac1d130fd4 578 SIZEOF_DNS_QUERY, PBUF_RAM);
mbed_official 0:51ac1d130fd4 579 if (p != NULL) {
mbed_official 0:51ac1d130fd4 580 LWIP_ASSERT("pbuf must be in one piece", p->next == NULL);
mbed_official 0:51ac1d130fd4 581 /* fill dns header */
mbed_official 0:51ac1d130fd4 582 hdr = (struct dns_hdr*)p->payload;
mbed_official 0:51ac1d130fd4 583 memset(hdr, 0, SIZEOF_DNS_HDR);
mbed_official 0:51ac1d130fd4 584 hdr->id = htons(id);
mbed_official 0:51ac1d130fd4 585 hdr->flags1 = DNS_FLAG1_RD;
mbed_official 0:51ac1d130fd4 586 hdr->numquestions = PP_HTONS(1);
mbed_official 0:51ac1d130fd4 587 query = (char*)hdr + SIZEOF_DNS_HDR;
mbed_official 0:51ac1d130fd4 588 pHostname = name;
mbed_official 0:51ac1d130fd4 589 --pHostname;
mbed_official 0:51ac1d130fd4 590
mbed_official 0:51ac1d130fd4 591 /* convert hostname into suitable query format. */
mbed_official 0:51ac1d130fd4 592 do {
mbed_official 0:51ac1d130fd4 593 ++pHostname;
mbed_official 0:51ac1d130fd4 594 nptr = query;
mbed_official 0:51ac1d130fd4 595 ++query;
mbed_official 0:51ac1d130fd4 596 for(n = 0; *pHostname != '.' && *pHostname != 0; ++pHostname) {
mbed_official 0:51ac1d130fd4 597 *query = *pHostname;
mbed_official 0:51ac1d130fd4 598 ++query;
mbed_official 0:51ac1d130fd4 599 ++n;
mbed_official 0:51ac1d130fd4 600 }
mbed_official 0:51ac1d130fd4 601 *nptr = n;
mbed_official 0:51ac1d130fd4 602 } while(*pHostname != 0);
mbed_official 0:51ac1d130fd4 603 *query++='\0';
mbed_official 0:51ac1d130fd4 604
mbed_official 0:51ac1d130fd4 605 /* fill dns query */
mbed_official 0:51ac1d130fd4 606 qry.type = PP_HTONS(DNS_RRTYPE_A);
mbed_official 0:51ac1d130fd4 607 qry.cls = PP_HTONS(DNS_RRCLASS_IN);
mbed_official 0:51ac1d130fd4 608 SMEMCPY(query, &qry, SIZEOF_DNS_QUERY);
mbed_official 0:51ac1d130fd4 609
mbed_official 0:51ac1d130fd4 610 /* resize pbuf to the exact dns query */
mbed_official 0:51ac1d130fd4 611 pbuf_realloc(p, (u16_t)((query + SIZEOF_DNS_QUERY) - ((char*)(p->payload))));
mbed_official 0:51ac1d130fd4 612
mbed_official 0:51ac1d130fd4 613 /* connect to the server for faster receiving */
mbed_official 0:51ac1d130fd4 614 udp_connect(dns_pcb, &dns_servers[numdns], DNS_SERVER_PORT);
mbed_official 0:51ac1d130fd4 615 /* send dns packet */
mbed_official 0:51ac1d130fd4 616 err = udp_sendto(dns_pcb, p, &dns_servers[numdns], DNS_SERVER_PORT);
mbed_official 0:51ac1d130fd4 617
mbed_official 0:51ac1d130fd4 618 /* free pbuf */
mbed_official 0:51ac1d130fd4 619 pbuf_free(p);
mbed_official 0:51ac1d130fd4 620 } else {
mbed_official 0:51ac1d130fd4 621 err = ERR_MEM;
mbed_official 0:51ac1d130fd4 622 }
mbed_official 0:51ac1d130fd4 623
mbed_official 0:51ac1d130fd4 624 return err;
mbed_official 0:51ac1d130fd4 625 }
mbed_official 0:51ac1d130fd4 626
mbed_official 0:51ac1d130fd4 627 /**
mbed_official 0:51ac1d130fd4 628 * dns_check_entry() - see if pEntry has not yet been queried and, if so, sends out a query.
mbed_official 0:51ac1d130fd4 629 * Check an entry in the dns_table:
mbed_official 0:51ac1d130fd4 630 * - send out query for new entries
mbed_official 0:51ac1d130fd4 631 * - retry old pending entries on timeout (also with different servers)
mbed_official 0:51ac1d130fd4 632 * - remove completed entries from the table if their TTL has expired
mbed_official 0:51ac1d130fd4 633 *
mbed_official 0:51ac1d130fd4 634 * @param i index of the dns_table entry to check
mbed_official 0:51ac1d130fd4 635 */
mbed_official 0:51ac1d130fd4 636 static void
mbed_official 0:51ac1d130fd4 637 dns_check_entry(u8_t i)
mbed_official 0:51ac1d130fd4 638 {
mbed_official 0:51ac1d130fd4 639 err_t err;
mbed_official 0:51ac1d130fd4 640 struct dns_table_entry *pEntry = &dns_table[i];
mbed_official 0:51ac1d130fd4 641
mbed_official 0:51ac1d130fd4 642 LWIP_ASSERT("array index out of bounds", i < DNS_TABLE_SIZE);
mbed_official 0:51ac1d130fd4 643
mbed_official 0:51ac1d130fd4 644 switch(pEntry->state) {
mbed_official 0:51ac1d130fd4 645
mbed_official 0:51ac1d130fd4 646 case DNS_STATE_NEW: {
mbed_official 0:51ac1d130fd4 647 /* initialize new entry */
mbed_official 0:51ac1d130fd4 648 pEntry->state = DNS_STATE_ASKING;
mbed_official 0:51ac1d130fd4 649 pEntry->numdns = 0;
mbed_official 0:51ac1d130fd4 650 pEntry->tmr = 1;
mbed_official 0:51ac1d130fd4 651 pEntry->retries = 0;
mbed_official 0:51ac1d130fd4 652
mbed_official 0:51ac1d130fd4 653 /* send DNS packet for this entry */
mbed_official 0:51ac1d130fd4 654 err = dns_send(pEntry->numdns, pEntry->name, i);
mbed_official 0:51ac1d130fd4 655 if (err != ERR_OK) {
mbed_official 0:51ac1d130fd4 656 LWIP_DEBUGF(DNS_DEBUG | LWIP_DBG_LEVEL_WARNING,
mbed_official 0:51ac1d130fd4 657 ("dns_send returned error: %s\n", lwip_strerr(err)));
mbed_official 0:51ac1d130fd4 658 }
mbed_official 0:51ac1d130fd4 659 break;
mbed_official 0:51ac1d130fd4 660 }
mbed_official 0:51ac1d130fd4 661
mbed_official 0:51ac1d130fd4 662 case DNS_STATE_ASKING: {
mbed_official 0:51ac1d130fd4 663 if (--pEntry->tmr == 0) {
mbed_official 0:51ac1d130fd4 664 if (++pEntry->retries == DNS_MAX_RETRIES) {
mbed_official 0:51ac1d130fd4 665 if ((pEntry->numdns+1<DNS_MAX_SERVERS) && !ip_addr_isany(&dns_servers[pEntry->numdns+1])) {
mbed_official 0:51ac1d130fd4 666 /* change of server */
mbed_official 0:51ac1d130fd4 667 pEntry->numdns++;
mbed_official 0:51ac1d130fd4 668 pEntry->tmr = 1;
mbed_official 0:51ac1d130fd4 669 pEntry->retries = 0;
mbed_official 0:51ac1d130fd4 670 break;
mbed_official 0:51ac1d130fd4 671 } else {
mbed_official 0:51ac1d130fd4 672 LWIP_DEBUGF(DNS_DEBUG, ("dns_check_entry: \"%s\": timeout\n", pEntry->name));
mbed_official 0:51ac1d130fd4 673 /* call specified callback function if provided */
mbed_official 0:51ac1d130fd4 674 if (pEntry->found)
mbed_official 0:51ac1d130fd4 675 (*pEntry->found)(pEntry->name, NULL, pEntry->arg);
mbed_official 0:51ac1d130fd4 676 /* flush this entry */
mbed_official 0:51ac1d130fd4 677 pEntry->state = DNS_STATE_UNUSED;
mbed_official 0:51ac1d130fd4 678 pEntry->found = NULL;
mbed_official 0:51ac1d130fd4 679 break;
mbed_official 0:51ac1d130fd4 680 }
mbed_official 0:51ac1d130fd4 681 }
mbed_official 0:51ac1d130fd4 682
mbed_official 0:51ac1d130fd4 683 /* wait longer for the next retry */
mbed_official 0:51ac1d130fd4 684 pEntry->tmr = pEntry->retries;
mbed_official 0:51ac1d130fd4 685
mbed_official 0:51ac1d130fd4 686 /* send DNS packet for this entry */
mbed_official 0:51ac1d130fd4 687 err = dns_send(pEntry->numdns, pEntry->name, i);
mbed_official 0:51ac1d130fd4 688 if (err != ERR_OK) {
mbed_official 0:51ac1d130fd4 689 LWIP_DEBUGF(DNS_DEBUG | LWIP_DBG_LEVEL_WARNING,
mbed_official 0:51ac1d130fd4 690 ("dns_send returned error: %s\n", lwip_strerr(err)));
mbed_official 0:51ac1d130fd4 691 }
mbed_official 0:51ac1d130fd4 692 }
mbed_official 0:51ac1d130fd4 693 break;
mbed_official 0:51ac1d130fd4 694 }
mbed_official 0:51ac1d130fd4 695
mbed_official 0:51ac1d130fd4 696 case DNS_STATE_DONE: {
mbed_official 0:51ac1d130fd4 697 /* if the time to live is nul */
mbed_official 0:51ac1d130fd4 698 if (--pEntry->ttl == 0) {
mbed_official 0:51ac1d130fd4 699 LWIP_DEBUGF(DNS_DEBUG, ("dns_check_entry: \"%s\": flush\n", pEntry->name));
mbed_official 0:51ac1d130fd4 700 /* flush this entry */
mbed_official 0:51ac1d130fd4 701 pEntry->state = DNS_STATE_UNUSED;
mbed_official 0:51ac1d130fd4 702 pEntry->found = NULL;
mbed_official 0:51ac1d130fd4 703 }
mbed_official 0:51ac1d130fd4 704 break;
mbed_official 0:51ac1d130fd4 705 }
mbed_official 0:51ac1d130fd4 706 case DNS_STATE_UNUSED:
mbed_official 0:51ac1d130fd4 707 /* nothing to do */
mbed_official 0:51ac1d130fd4 708 break;
mbed_official 0:51ac1d130fd4 709 default:
mbed_official 0:51ac1d130fd4 710 LWIP_ASSERT("unknown dns_table entry state:", 0);
mbed_official 0:51ac1d130fd4 711 break;
mbed_official 0:51ac1d130fd4 712 }
mbed_official 0:51ac1d130fd4 713 }
mbed_official 0:51ac1d130fd4 714
mbed_official 0:51ac1d130fd4 715 /**
mbed_official 0:51ac1d130fd4 716 * Call dns_check_entry for each entry in dns_table - check all entries.
mbed_official 0:51ac1d130fd4 717 */
mbed_official 0:51ac1d130fd4 718 static void
mbed_official 0:51ac1d130fd4 719 dns_check_entries(void)
mbed_official 0:51ac1d130fd4 720 {
mbed_official 0:51ac1d130fd4 721 u8_t i;
mbed_official 0:51ac1d130fd4 722
mbed_official 0:51ac1d130fd4 723 for (i = 0; i < DNS_TABLE_SIZE; ++i) {
mbed_official 0:51ac1d130fd4 724 dns_check_entry(i);
mbed_official 0:51ac1d130fd4 725 }
mbed_official 0:51ac1d130fd4 726 }
mbed_official 0:51ac1d130fd4 727
mbed_official 0:51ac1d130fd4 728 /**
mbed_official 0:51ac1d130fd4 729 * Receive input function for DNS response packets arriving for the dns UDP pcb.
mbed_official 0:51ac1d130fd4 730 *
mbed_official 0:51ac1d130fd4 731 * @params see udp.h
mbed_official 0:51ac1d130fd4 732 */
mbed_official 0:51ac1d130fd4 733 static void
mbed_official 0:51ac1d130fd4 734 dns_recv(void *arg, struct udp_pcb *pcb, struct pbuf *p, ip_addr_t *addr, u16_t port)
mbed_official 0:51ac1d130fd4 735 {
mbed_official 0:51ac1d130fd4 736 u16_t i;
mbed_official 0:51ac1d130fd4 737 char *pHostname;
mbed_official 0:51ac1d130fd4 738 struct dns_hdr *hdr;
mbed_official 0:51ac1d130fd4 739 struct dns_answer ans;
mbed_official 0:51ac1d130fd4 740 struct dns_table_entry *pEntry;
mbed_official 0:51ac1d130fd4 741 u16_t nquestions, nanswers;
mbed_official 0:51ac1d130fd4 742
mbed_official 0:51ac1d130fd4 743 LWIP_UNUSED_ARG(arg);
mbed_official 0:51ac1d130fd4 744 LWIP_UNUSED_ARG(pcb);
mbed_official 0:51ac1d130fd4 745 LWIP_UNUSED_ARG(addr);
mbed_official 0:51ac1d130fd4 746 LWIP_UNUSED_ARG(port);
mbed_official 0:51ac1d130fd4 747
mbed_official 0:51ac1d130fd4 748 /* is the dns message too big ? */
mbed_official 0:51ac1d130fd4 749 if (p->tot_len > DNS_MSG_SIZE) {
mbed_official 0:51ac1d130fd4 750 LWIP_DEBUGF(DNS_DEBUG, ("dns_recv: pbuf too big\n"));
mbed_official 0:51ac1d130fd4 751 /* free pbuf and return */
mbed_official 0:51ac1d130fd4 752 goto memerr;
mbed_official 0:51ac1d130fd4 753 }
mbed_official 0:51ac1d130fd4 754
mbed_official 0:51ac1d130fd4 755 /* is the dns message big enough ? */
mbed_official 0:51ac1d130fd4 756 if (p->tot_len < (SIZEOF_DNS_HDR + SIZEOF_DNS_QUERY + SIZEOF_DNS_ANSWER)) {
mbed_official 0:51ac1d130fd4 757 LWIP_DEBUGF(DNS_DEBUG, ("dns_recv: pbuf too small\n"));
mbed_official 0:51ac1d130fd4 758 /* free pbuf and return */
mbed_official 0:51ac1d130fd4 759 goto memerr;
mbed_official 0:51ac1d130fd4 760 }
mbed_official 0:51ac1d130fd4 761
mbed_official 0:51ac1d130fd4 762 /* copy dns payload inside static buffer for processing */
mbed_official 0:51ac1d130fd4 763 if (pbuf_copy_partial(p, dns_payload, p->tot_len, 0) == p->tot_len) {
mbed_official 0:51ac1d130fd4 764 /* The ID in the DNS header should be our entry into the name table. */
mbed_official 0:51ac1d130fd4 765 hdr = (struct dns_hdr*)dns_payload;
mbed_official 0:51ac1d130fd4 766 i = htons(hdr->id);
mbed_official 0:51ac1d130fd4 767 if (i < DNS_TABLE_SIZE) {
mbed_official 0:51ac1d130fd4 768 pEntry = &dns_table[i];
mbed_official 0:51ac1d130fd4 769 if(pEntry->state == DNS_STATE_ASKING) {
mbed_official 0:51ac1d130fd4 770 /* This entry is now completed. */
mbed_official 0:51ac1d130fd4 771 pEntry->state = DNS_STATE_DONE;
mbed_official 0:51ac1d130fd4 772 pEntry->err = hdr->flags2 & DNS_FLAG2_ERR_MASK;
mbed_official 0:51ac1d130fd4 773
mbed_official 0:51ac1d130fd4 774 /* We only care about the question(s) and the answers. The authrr
mbed_official 0:51ac1d130fd4 775 and the extrarr are simply discarded. */
mbed_official 0:51ac1d130fd4 776 nquestions = htons(hdr->numquestions);
mbed_official 0:51ac1d130fd4 777 nanswers = htons(hdr->numanswers);
mbed_official 0:51ac1d130fd4 778
mbed_official 0:51ac1d130fd4 779 /* Check for error. If so, call callback to inform. */
mbed_official 0:51ac1d130fd4 780 if (((hdr->flags1 & DNS_FLAG1_RESPONSE) == 0) || (pEntry->err != 0) || (nquestions != 1)) {
mbed_official 0:51ac1d130fd4 781 LWIP_DEBUGF(DNS_DEBUG, ("dns_recv: \"%s\": error in flags\n", pEntry->name));
mbed_official 0:51ac1d130fd4 782 /* call callback to indicate error, clean up memory and return */
mbed_official 0:51ac1d130fd4 783 goto responseerr;
mbed_official 0:51ac1d130fd4 784 }
mbed_official 0:51ac1d130fd4 785
mbed_official 0:51ac1d130fd4 786 #if DNS_DOES_NAME_CHECK
mbed_official 0:51ac1d130fd4 787 /* Check if the name in the "question" part match with the name in the entry. */
mbed_official 0:51ac1d130fd4 788 if (dns_compare_name((unsigned char *)(pEntry->name), (unsigned char *)dns_payload + SIZEOF_DNS_HDR) != 0) {
mbed_official 0:51ac1d130fd4 789 LWIP_DEBUGF(DNS_DEBUG, ("dns_recv: \"%s\": response not match to query\n", pEntry->name));
mbed_official 0:51ac1d130fd4 790 /* call callback to indicate error, clean up memory and return */
mbed_official 0:51ac1d130fd4 791 goto responseerr;
mbed_official 0:51ac1d130fd4 792 }
mbed_official 0:51ac1d130fd4 793 #endif /* DNS_DOES_NAME_CHECK */
mbed_official 0:51ac1d130fd4 794
mbed_official 0:51ac1d130fd4 795 /* Skip the name in the "question" part */
mbed_official 0:51ac1d130fd4 796 pHostname = (char *) dns_parse_name((unsigned char *)dns_payload + SIZEOF_DNS_HDR) + SIZEOF_DNS_QUERY;
mbed_official 0:51ac1d130fd4 797
mbed_official 0:51ac1d130fd4 798 while (nanswers > 0) {
mbed_official 0:51ac1d130fd4 799 /* skip answer resource record's host name */
mbed_official 0:51ac1d130fd4 800 pHostname = (char *) dns_parse_name((unsigned char *)pHostname);
mbed_official 0:51ac1d130fd4 801
mbed_official 0:51ac1d130fd4 802 /* Check for IP address type and Internet class. Others are discarded. */
mbed_official 0:51ac1d130fd4 803 SMEMCPY(&ans, pHostname, SIZEOF_DNS_ANSWER);
mbed_official 0:51ac1d130fd4 804 if((ans.type == PP_HTONS(DNS_RRTYPE_A)) && (ans.cls == PP_HTONS(DNS_RRCLASS_IN)) &&
mbed_official 0:51ac1d130fd4 805 (ans.len == PP_HTONS(sizeof(ip_addr_t))) ) {
mbed_official 0:51ac1d130fd4 806 /* read the answer resource record's TTL, and maximize it if needed */
mbed_official 0:51ac1d130fd4 807 pEntry->ttl = ntohl(ans.ttl);
mbed_official 0:51ac1d130fd4 808 if (pEntry->ttl > DNS_MAX_TTL) {
mbed_official 0:51ac1d130fd4 809 pEntry->ttl = DNS_MAX_TTL;
mbed_official 0:51ac1d130fd4 810 }
mbed_official 0:51ac1d130fd4 811 /* read the IP address after answer resource record's header */
mbed_official 0:51ac1d130fd4 812 SMEMCPY(&(pEntry->ipaddr), (pHostname+SIZEOF_DNS_ANSWER), sizeof(ip_addr_t));
mbed_official 0:51ac1d130fd4 813 LWIP_DEBUGF(DNS_DEBUG, ("dns_recv: \"%s\": response = ", pEntry->name));
mbed_official 0:51ac1d130fd4 814 ip_addr_debug_print(DNS_DEBUG, (&(pEntry->ipaddr)));
mbed_official 0:51ac1d130fd4 815 LWIP_DEBUGF(DNS_DEBUG, ("\n"));
mbed_official 0:51ac1d130fd4 816 /* call specified callback function if provided */
mbed_official 0:51ac1d130fd4 817 if (pEntry->found) {
mbed_official 0:51ac1d130fd4 818 (*pEntry->found)(pEntry->name, &pEntry->ipaddr, pEntry->arg);
mbed_official 0:51ac1d130fd4 819 }
mbed_official 0:51ac1d130fd4 820 /* deallocate memory and return */
mbed_official 0:51ac1d130fd4 821 goto memerr;
mbed_official 0:51ac1d130fd4 822 } else {
mbed_official 0:51ac1d130fd4 823 pHostname = pHostname + SIZEOF_DNS_ANSWER + htons(ans.len);
mbed_official 0:51ac1d130fd4 824 }
mbed_official 0:51ac1d130fd4 825 --nanswers;
mbed_official 0:51ac1d130fd4 826 }
mbed_official 0:51ac1d130fd4 827 LWIP_DEBUGF(DNS_DEBUG, ("dns_recv: \"%s\": error in response\n", pEntry->name));
mbed_official 0:51ac1d130fd4 828 /* call callback to indicate error, clean up memory and return */
mbed_official 0:51ac1d130fd4 829 goto responseerr;
mbed_official 0:51ac1d130fd4 830 }
mbed_official 0:51ac1d130fd4 831 }
mbed_official 0:51ac1d130fd4 832 }
mbed_official 0:51ac1d130fd4 833
mbed_official 0:51ac1d130fd4 834 /* deallocate memory and return */
mbed_official 0:51ac1d130fd4 835 goto memerr;
mbed_official 0:51ac1d130fd4 836
mbed_official 0:51ac1d130fd4 837 responseerr:
mbed_official 0:51ac1d130fd4 838 /* ERROR: call specified callback function with NULL as name to indicate an error */
mbed_official 0:51ac1d130fd4 839 if (pEntry->found) {
mbed_official 0:51ac1d130fd4 840 (*pEntry->found)(pEntry->name, NULL, pEntry->arg);
mbed_official 0:51ac1d130fd4 841 }
mbed_official 0:51ac1d130fd4 842 /* flush this entry */
mbed_official 0:51ac1d130fd4 843 pEntry->state = DNS_STATE_UNUSED;
mbed_official 0:51ac1d130fd4 844 pEntry->found = NULL;
mbed_official 0:51ac1d130fd4 845
mbed_official 0:51ac1d130fd4 846 memerr:
mbed_official 0:51ac1d130fd4 847 /* free pbuf */
mbed_official 0:51ac1d130fd4 848 pbuf_free(p);
mbed_official 0:51ac1d130fd4 849 return;
mbed_official 0:51ac1d130fd4 850 }
mbed_official 0:51ac1d130fd4 851
mbed_official 0:51ac1d130fd4 852 /**
mbed_official 0:51ac1d130fd4 853 * Queues a new hostname to resolve and sends out a DNS query for that hostname
mbed_official 0:51ac1d130fd4 854 *
mbed_official 0:51ac1d130fd4 855 * @param name the hostname that is to be queried
mbed_official 0:51ac1d130fd4 856 * @param found a callback founction to be called on success, failure or timeout
mbed_official 0:51ac1d130fd4 857 * @param callback_arg argument to pass to the callback function
mbed_official 0:51ac1d130fd4 858 * @return @return a err_t return code.
mbed_official 0:51ac1d130fd4 859 */
mbed_official 0:51ac1d130fd4 860 static err_t
mbed_official 0:51ac1d130fd4 861 dns_enqueue(const char *name, dns_found_callback found, void *callback_arg)
mbed_official 0:51ac1d130fd4 862 {
mbed_official 0:51ac1d130fd4 863 u8_t i;
mbed_official 0:51ac1d130fd4 864 u8_t lseq, lseqi;
mbed_official 0:51ac1d130fd4 865 struct dns_table_entry *pEntry = NULL;
mbed_official 0:51ac1d130fd4 866 size_t namelen;
mbed_official 0:51ac1d130fd4 867
mbed_official 0:51ac1d130fd4 868 /* search an unused entry, or the oldest one */
mbed_official 0:51ac1d130fd4 869 lseq = lseqi = 0;
mbed_official 0:51ac1d130fd4 870 for (i = 0; i < DNS_TABLE_SIZE; ++i) {
mbed_official 0:51ac1d130fd4 871 pEntry = &dns_table[i];
mbed_official 0:51ac1d130fd4 872 /* is it an unused entry ? */
mbed_official 0:51ac1d130fd4 873 if (pEntry->state == DNS_STATE_UNUSED)
mbed_official 0:51ac1d130fd4 874 break;
mbed_official 0:51ac1d130fd4 875
mbed_official 0:51ac1d130fd4 876 /* check if this is the oldest completed entry */
mbed_official 0:51ac1d130fd4 877 if (pEntry->state == DNS_STATE_DONE) {
mbed_official 0:51ac1d130fd4 878 if ((dns_seqno - pEntry->seqno) > lseq) {
mbed_official 0:51ac1d130fd4 879 lseq = dns_seqno - pEntry->seqno;
mbed_official 0:51ac1d130fd4 880 lseqi = i;
mbed_official 0:51ac1d130fd4 881 }
mbed_official 0:51ac1d130fd4 882 }
mbed_official 0:51ac1d130fd4 883 }
mbed_official 0:51ac1d130fd4 884
mbed_official 0:51ac1d130fd4 885 /* if we don't have found an unused entry, use the oldest completed one */
mbed_official 0:51ac1d130fd4 886 if (i == DNS_TABLE_SIZE) {
mbed_official 0:51ac1d130fd4 887 if ((lseqi >= DNS_TABLE_SIZE) || (dns_table[lseqi].state != DNS_STATE_DONE)) {
mbed_official 0:51ac1d130fd4 888 /* no entry can't be used now, table is full */
mbed_official 0:51ac1d130fd4 889 LWIP_DEBUGF(DNS_DEBUG, ("dns_enqueue: \"%s\": DNS entries table is full\n", name));
mbed_official 0:51ac1d130fd4 890 return ERR_MEM;
mbed_official 0:51ac1d130fd4 891 } else {
mbed_official 0:51ac1d130fd4 892 /* use the oldest completed one */
mbed_official 0:51ac1d130fd4 893 i = lseqi;
mbed_official 0:51ac1d130fd4 894 pEntry = &dns_table[i];
mbed_official 0:51ac1d130fd4 895 }
mbed_official 0:51ac1d130fd4 896 }
mbed_official 0:51ac1d130fd4 897
mbed_official 0:51ac1d130fd4 898 /* use this entry */
mbed_official 0:51ac1d130fd4 899 LWIP_DEBUGF(DNS_DEBUG, ("dns_enqueue: \"%s\": use DNS entry %"U16_F"\n", name, (u16_t)(i)));
mbed_official 0:51ac1d130fd4 900
mbed_official 0:51ac1d130fd4 901 /* fill the entry */
mbed_official 0:51ac1d130fd4 902 pEntry->state = DNS_STATE_NEW;
mbed_official 0:51ac1d130fd4 903 pEntry->seqno = dns_seqno++;
mbed_official 0:51ac1d130fd4 904 pEntry->found = found;
mbed_official 0:51ac1d130fd4 905 pEntry->arg = callback_arg;
mbed_official 0:51ac1d130fd4 906 namelen = LWIP_MIN(strlen(name), DNS_MAX_NAME_LENGTH-1);
mbed_official 0:51ac1d130fd4 907 MEMCPY(pEntry->name, name, namelen);
mbed_official 0:51ac1d130fd4 908 pEntry->name[namelen] = 0;
mbed_official 0:51ac1d130fd4 909
mbed_official 0:51ac1d130fd4 910 /* force to send query without waiting timer */
mbed_official 0:51ac1d130fd4 911 dns_check_entry(i);
mbed_official 0:51ac1d130fd4 912
mbed_official 0:51ac1d130fd4 913 /* dns query is enqueued */
mbed_official 0:51ac1d130fd4 914 return ERR_INPROGRESS;
mbed_official 0:51ac1d130fd4 915 }
mbed_official 0:51ac1d130fd4 916
mbed_official 0:51ac1d130fd4 917 /**
mbed_official 0:51ac1d130fd4 918 * Resolve a hostname (string) into an IP address.
mbed_official 0:51ac1d130fd4 919 * NON-BLOCKING callback version for use with raw API!!!
mbed_official 0:51ac1d130fd4 920 *
mbed_official 0:51ac1d130fd4 921 * Returns immediately with one of err_t return codes:
mbed_official 0:51ac1d130fd4 922 * - ERR_OK if hostname is a valid IP address string or the host
mbed_official 0:51ac1d130fd4 923 * name is already in the local names table.
mbed_official 0:51ac1d130fd4 924 * - ERR_INPROGRESS enqueue a request to be sent to the DNS server
mbed_official 0:51ac1d130fd4 925 * for resolution if no errors are present.
mbed_official 0:51ac1d130fd4 926 * - ERR_ARG: dns client not initialized or invalid hostname
mbed_official 0:51ac1d130fd4 927 *
mbed_official 0:51ac1d130fd4 928 * @param hostname the hostname that is to be queried
mbed_official 0:51ac1d130fd4 929 * @param addr pointer to a ip_addr_t where to store the address if it is already
mbed_official 0:51ac1d130fd4 930 * cached in the dns_table (only valid if ERR_OK is returned!)
mbed_official 0:51ac1d130fd4 931 * @param found a callback function to be called on success, failure or timeout (only if
mbed_official 0:51ac1d130fd4 932 * ERR_INPROGRESS is returned!)
mbed_official 0:51ac1d130fd4 933 * @param callback_arg argument to pass to the callback function
mbed_official 0:51ac1d130fd4 934 * @return a err_t return code.
mbed_official 0:51ac1d130fd4 935 */
mbed_official 0:51ac1d130fd4 936 err_t
mbed_official 0:51ac1d130fd4 937 dns_gethostbyname(const char *hostname, ip_addr_t *addr, dns_found_callback found,
mbed_official 0:51ac1d130fd4 938 void *callback_arg)
mbed_official 0:51ac1d130fd4 939 {
mbed_official 0:51ac1d130fd4 940 u32_t ipaddr;
mbed_official 0:51ac1d130fd4 941 /* not initialized or no valid server yet, or invalid addr pointer
mbed_official 0:51ac1d130fd4 942 * or invalid hostname or invalid hostname length */
mbed_official 0:51ac1d130fd4 943 if ((dns_pcb == NULL) || (addr == NULL) ||
mbed_official 0:51ac1d130fd4 944 (!hostname) || (!hostname[0]) ||
mbed_official 0:51ac1d130fd4 945 (strlen(hostname) >= DNS_MAX_NAME_LENGTH)) {
mbed_official 0:51ac1d130fd4 946 return ERR_ARG;
mbed_official 0:51ac1d130fd4 947 }
mbed_official 0:51ac1d130fd4 948
mbed_official 0:51ac1d130fd4 949 #if LWIP_HAVE_LOOPIF
mbed_official 0:51ac1d130fd4 950 if (strcmp(hostname, "localhost")==0) {
mbed_official 0:51ac1d130fd4 951 ip_addr_set_loopback(addr);
mbed_official 0:51ac1d130fd4 952 return ERR_OK;
mbed_official 0:51ac1d130fd4 953 }
mbed_official 0:51ac1d130fd4 954 #endif /* LWIP_HAVE_LOOPIF */
mbed_official 0:51ac1d130fd4 955
mbed_official 0:51ac1d130fd4 956 /* host name already in octet notation? set ip addr and return ERR_OK */
mbed_official 0:51ac1d130fd4 957 ipaddr = ipaddr_addr(hostname);
mbed_official 0:51ac1d130fd4 958 if (ipaddr == IPADDR_NONE) {
mbed_official 0:51ac1d130fd4 959 /* already have this address cached? */
mbed_official 0:51ac1d130fd4 960 ipaddr = dns_lookup(hostname);
mbed_official 0:51ac1d130fd4 961 }
mbed_official 0:51ac1d130fd4 962 if (ipaddr != IPADDR_NONE) {
mbed_official 0:51ac1d130fd4 963 ip4_addr_set_u32(addr, ipaddr);
mbed_official 0:51ac1d130fd4 964 return ERR_OK;
mbed_official 0:51ac1d130fd4 965 }
mbed_official 0:51ac1d130fd4 966
mbed_official 0:51ac1d130fd4 967 /* queue query with specified callback */
mbed_official 0:51ac1d130fd4 968 return dns_enqueue(hostname, found, callback_arg);
mbed_official 0:51ac1d130fd4 969 }
mbed_official 0:51ac1d130fd4 970
mbed_official 0:51ac1d130fd4 971 #endif /* LWIP_DNS */