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NetServices/lwip/core/dns.c@0:4edb816d21e1, 2015-10-16 (annotated)

Committer:
ICTFBI
Date:
Fri Oct 16 14:28:26 2015 +0000
Revision:
0:4edb816d21e1
Pre-update 16-10-15

Who changed what in which revision?

UserRevisionLine numberNew contents of line
ICTFBI 0:4edb816d21e1 1 /**
ICTFBI 0:4edb816d21e1 2 * @file
ICTFBI 0:4edb816d21e1 3 * DNS - host name to IP address resolver.
ICTFBI 0:4edb816d21e1 4 *
ICTFBI 0:4edb816d21e1 5 */
ICTFBI 0:4edb816d21e1 6
ICTFBI 0:4edb816d21e1 7 /**
ICTFBI 0:4edb816d21e1 8
ICTFBI 0:4edb816d21e1 9 * This file implements a DNS host name to IP address resolver.
ICTFBI 0:4edb816d21e1 10
ICTFBI 0:4edb816d21e1 11 * Port to lwIP from uIP
ICTFBI 0:4edb816d21e1 12 * by Jim Pettinato April 2007
ICTFBI 0:4edb816d21e1 13
ICTFBI 0:4edb816d21e1 14 * uIP version Copyright (c) 2002-2003, Adam Dunkels.
ICTFBI 0:4edb816d21e1 15 * All rights reserved.
ICTFBI 0:4edb816d21e1 16 *
ICTFBI 0:4edb816d21e1 17 * Redistribution and use in source and binary forms, with or without
ICTFBI 0:4edb816d21e1 18 * modification, are permitted provided that the following conditions
ICTFBI 0:4edb816d21e1 19 * are met:
ICTFBI 0:4edb816d21e1 20 * 1. Redistributions of source code must retain the above copyright
ICTFBI 0:4edb816d21e1 21 * notice, this list of conditions and the following disclaimer.
ICTFBI 0:4edb816d21e1 22 * 2. Redistributions in binary form must reproduce the above copyright
ICTFBI 0:4edb816d21e1 23 * notice, this list of conditions and the following disclaimer in the
ICTFBI 0:4edb816d21e1 24 * documentation and/or other materials provided with the distribution.
ICTFBI 0:4edb816d21e1 25 * 3. The name of the author may not be used to endorse or promote
ICTFBI 0:4edb816d21e1 26 * products derived from this software without specific prior
ICTFBI 0:4edb816d21e1 27 * written permission.
ICTFBI 0:4edb816d21e1 28 *
ICTFBI 0:4edb816d21e1 29 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
ICTFBI 0:4edb816d21e1 30 * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
ICTFBI 0:4edb816d21e1 31 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
ICTFBI 0:4edb816d21e1 32 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
ICTFBI 0:4edb816d21e1 33 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
ICTFBI 0:4edb816d21e1 34 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
ICTFBI 0:4edb816d21e1 35 * GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
ICTFBI 0:4edb816d21e1 36 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
ICTFBI 0:4edb816d21e1 37 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
ICTFBI 0:4edb816d21e1 38 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
ICTFBI 0:4edb816d21e1 39 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
ICTFBI 0:4edb816d21e1 40 *
ICTFBI 0:4edb816d21e1 41 *
ICTFBI 0:4edb816d21e1 42 * DNS.C
ICTFBI 0:4edb816d21e1 43 *
ICTFBI 0:4edb816d21e1 44 * The lwIP DNS resolver functions are used to lookup a host name and
ICTFBI 0:4edb816d21e1 45 * map it to a numerical IP address. It maintains a list of resolved
ICTFBI 0:4edb816d21e1 46 * hostnames that can be queried with the dns_lookup() function.
ICTFBI 0:4edb816d21e1 47 * New hostnames can be resolved using the dns_query() function.
ICTFBI 0:4edb816d21e1 48 *
ICTFBI 0:4edb816d21e1 49 * The lwIP version of the resolver also adds a non-blocking version of
ICTFBI 0:4edb816d21e1 50 * gethostbyname() that will work with a raw API application. This function
ICTFBI 0:4edb816d21e1 51 * checks for an IP address string first and converts it if it is valid.
ICTFBI 0:4edb816d21e1 52 * gethostbyname() then does a dns_lookup() to see if the name is
ICTFBI 0:4edb816d21e1 53 * already in the table. If so, the IP is returned. If not, a query is
ICTFBI 0:4edb816d21e1 54 * issued and the function returns with a ERR_INPROGRESS status. The app
ICTFBI 0:4edb816d21e1 55 * using the dns client must then go into a waiting state.
ICTFBI 0:4edb816d21e1 56 *
ICTFBI 0:4edb816d21e1 57 * Once a hostname has been resolved (or found to be non-existent),
ICTFBI 0:4edb816d21e1 58 * the resolver code calls a specified callback function (which
ICTFBI 0:4edb816d21e1 59 * must be implemented by the module that uses the resolver).
ICTFBI 0:4edb816d21e1 60 */
ICTFBI 0:4edb816d21e1 61
ICTFBI 0:4edb816d21e1 62 /*-----------------------------------------------------------------------------
ICTFBI 0:4edb816d21e1 63 * RFC 1035 - Domain names - implementation and specification
ICTFBI 0:4edb816d21e1 64 * RFC 2181 - Clarifications to the DNS Specification
ICTFBI 0:4edb816d21e1 65 *----------------------------------------------------------------------------*/
ICTFBI 0:4edb816d21e1 66
ICTFBI 0:4edb816d21e1 67 /** @todo: define good default values (rfc compliance) */
ICTFBI 0:4edb816d21e1 68 /** @todo: improve answer parsing, more checkings... */
ICTFBI 0:4edb816d21e1 69 /** @todo: check RFC1035 - 7.3. Processing responses */
ICTFBI 0:4edb816d21e1 70
ICTFBI 0:4edb816d21e1 71 /*-----------------------------------------------------------------------------
ICTFBI 0:4edb816d21e1 72 * Includes
ICTFBI 0:4edb816d21e1 73 *----------------------------------------------------------------------------*/
ICTFBI 0:4edb816d21e1 74
ICTFBI 0:4edb816d21e1 75 #include "lwip/opt.h"
ICTFBI 0:4edb816d21e1 76
ICTFBI 0:4edb816d21e1 77 #if LWIP_DNS /* don't build if not configured for use in lwipopts.h */
ICTFBI 0:4edb816d21e1 78
ICTFBI 0:4edb816d21e1 79 #include "lwip/udp.h"
ICTFBI 0:4edb816d21e1 80 #include "lwip/mem.h"
ICTFBI 0:4edb816d21e1 81 #include "lwip/memp.h"
ICTFBI 0:4edb816d21e1 82 #include "lwip/dns.h"
ICTFBI 0:4edb816d21e1 83
ICTFBI 0:4edb816d21e1 84 #include <string.h>
ICTFBI 0:4edb816d21e1 85
ICTFBI 0:4edb816d21e1 86 /** DNS server IP address */
ICTFBI 0:4edb816d21e1 87 #ifndef DNS_SERVER_ADDRESS
ICTFBI 0:4edb816d21e1 88 #define DNS_SERVER_ADDRESS(ipaddr) (ip4_addr_set_u32(ipaddr, ipaddr_addr("208.67.222.222"))) /* resolver1.opendns.com */
ICTFBI 0:4edb816d21e1 89 #endif
ICTFBI 0:4edb816d21e1 90
ICTFBI 0:4edb816d21e1 91 /** DNS server port address */
ICTFBI 0:4edb816d21e1 92 #ifndef DNS_SERVER_PORT
ICTFBI 0:4edb816d21e1 93 #define DNS_SERVER_PORT 53
ICTFBI 0:4edb816d21e1 94 #endif
ICTFBI 0:4edb816d21e1 95
ICTFBI 0:4edb816d21e1 96 /** DNS maximum number of retries when asking for a name, before "timeout". */
ICTFBI 0:4edb816d21e1 97 #ifndef DNS_MAX_RETRIES
ICTFBI 0:4edb816d21e1 98 #define DNS_MAX_RETRIES 4
ICTFBI 0:4edb816d21e1 99 #endif
ICTFBI 0:4edb816d21e1 100
ICTFBI 0:4edb816d21e1 101 /** DNS resource record max. TTL (one week as default) */
ICTFBI 0:4edb816d21e1 102 #ifndef DNS_MAX_TTL
ICTFBI 0:4edb816d21e1 103 #define DNS_MAX_TTL 604800
ICTFBI 0:4edb816d21e1 104 #endif
ICTFBI 0:4edb816d21e1 105
ICTFBI 0:4edb816d21e1 106 /* DNS protocol flags */
ICTFBI 0:4edb816d21e1 107 #define DNS_FLAG1_RESPONSE 0x80
ICTFBI 0:4edb816d21e1 108 #define DNS_FLAG1_OPCODE_STATUS 0x10
ICTFBI 0:4edb816d21e1 109 #define DNS_FLAG1_OPCODE_INVERSE 0x08
ICTFBI 0:4edb816d21e1 110 #define DNS_FLAG1_OPCODE_STANDARD 0x00
ICTFBI 0:4edb816d21e1 111 #define DNS_FLAG1_AUTHORATIVE 0x04
ICTFBI 0:4edb816d21e1 112 #define DNS_FLAG1_TRUNC 0x02
ICTFBI 0:4edb816d21e1 113 #define DNS_FLAG1_RD 0x01
ICTFBI 0:4edb816d21e1 114 #define DNS_FLAG2_RA 0x80
ICTFBI 0:4edb816d21e1 115 #define DNS_FLAG2_ERR_MASK 0x0f
ICTFBI 0:4edb816d21e1 116 #define DNS_FLAG2_ERR_NONE 0x00
ICTFBI 0:4edb816d21e1 117 #define DNS_FLAG2_ERR_NAME 0x03
ICTFBI 0:4edb816d21e1 118
ICTFBI 0:4edb816d21e1 119 /* DNS protocol states */
ICTFBI 0:4edb816d21e1 120 #define DNS_STATE_UNUSED 0
ICTFBI 0:4edb816d21e1 121 #define DNS_STATE_NEW 1
ICTFBI 0:4edb816d21e1 122 #define DNS_STATE_ASKING 2
ICTFBI 0:4edb816d21e1 123 #define DNS_STATE_DONE 3
ICTFBI 0:4edb816d21e1 124
ICTFBI 0:4edb816d21e1 125 #ifdef PACK_STRUCT_USE_INCLUDES
ICTFBI 0:4edb816d21e1 126 # include "arch/bpstruct.h"
ICTFBI 0:4edb816d21e1 127 #endif
ICTFBI 0:4edb816d21e1 128 PACK_STRUCT_BEGIN
ICTFBI 0:4edb816d21e1 129 /** DNS message header */
ICTFBI 0:4edb816d21e1 130 struct dns_hdr {
ICTFBI 0:4edb816d21e1 131 PACK_STRUCT_FIELD(u16_t id);
ICTFBI 0:4edb816d21e1 132 PACK_STRUCT_FIELD(u8_t flags1);
ICTFBI 0:4edb816d21e1 133 PACK_STRUCT_FIELD(u8_t flags2);
ICTFBI 0:4edb816d21e1 134 PACK_STRUCT_FIELD(u16_t numquestions);
ICTFBI 0:4edb816d21e1 135 PACK_STRUCT_FIELD(u16_t numanswers);
ICTFBI 0:4edb816d21e1 136 PACK_STRUCT_FIELD(u16_t numauthrr);
ICTFBI 0:4edb816d21e1 137 PACK_STRUCT_FIELD(u16_t numextrarr);
ICTFBI 0:4edb816d21e1 138 } PACK_STRUCT_STRUCT;
ICTFBI 0:4edb816d21e1 139 PACK_STRUCT_END
ICTFBI 0:4edb816d21e1 140 #ifdef PACK_STRUCT_USE_INCLUDES
ICTFBI 0:4edb816d21e1 141 # include "arch/epstruct.h"
ICTFBI 0:4edb816d21e1 142 #endif
ICTFBI 0:4edb816d21e1 143 #define SIZEOF_DNS_HDR 12
ICTFBI 0:4edb816d21e1 144
ICTFBI 0:4edb816d21e1 145 /** DNS query message structure.
ICTFBI 0:4edb816d21e1 146 No packing needed: only used locally on the stack. */
ICTFBI 0:4edb816d21e1 147 struct dns_query {
ICTFBI 0:4edb816d21e1 148 /* DNS query record starts with either a domain name or a pointer
ICTFBI 0:4edb816d21e1 149 to a name already present somewhere in the packet. */
ICTFBI 0:4edb816d21e1 150 u16_t type;
ICTFBI 0:4edb816d21e1 151 u16_t cls;
ICTFBI 0:4edb816d21e1 152 };
ICTFBI 0:4edb816d21e1 153 #define SIZEOF_DNS_QUERY 4
ICTFBI 0:4edb816d21e1 154
ICTFBI 0:4edb816d21e1 155 /** DNS answer message structure.
ICTFBI 0:4edb816d21e1 156 No packing needed: only used locally on the stack. */
ICTFBI 0:4edb816d21e1 157 struct dns_answer {
ICTFBI 0:4edb816d21e1 158 /* DNS answer record starts with either a domain name or a pointer
ICTFBI 0:4edb816d21e1 159 to a name already present somewhere in the packet. */
ICTFBI 0:4edb816d21e1 160 u16_t type;
ICTFBI 0:4edb816d21e1 161 u16_t cls;
ICTFBI 0:4edb816d21e1 162 u32_t ttl;
ICTFBI 0:4edb816d21e1 163 u16_t len;
ICTFBI 0:4edb816d21e1 164 };
ICTFBI 0:4edb816d21e1 165 #define SIZEOF_DNS_ANSWER 10
ICTFBI 0:4edb816d21e1 166
ICTFBI 0:4edb816d21e1 167 /** DNS table entry */
ICTFBI 0:4edb816d21e1 168 struct dns_table_entry {
ICTFBI 0:4edb816d21e1 169 u8_t state;
ICTFBI 0:4edb816d21e1 170 u8_t numdns;
ICTFBI 0:4edb816d21e1 171 u8_t tmr;
ICTFBI 0:4edb816d21e1 172 u8_t retries;
ICTFBI 0:4edb816d21e1 173 u8_t seqno;
ICTFBI 0:4edb816d21e1 174 u8_t err;
ICTFBI 0:4edb816d21e1 175 u32_t ttl;
ICTFBI 0:4edb816d21e1 176 char name[DNS_MAX_NAME_LENGTH];
ICTFBI 0:4edb816d21e1 177 ip_addr_t ipaddr;
ICTFBI 0:4edb816d21e1 178 /* pointer to callback on DNS query done */
ICTFBI 0:4edb816d21e1 179 dns_found_callback found;
ICTFBI 0:4edb816d21e1 180 void *arg;
ICTFBI 0:4edb816d21e1 181 };
ICTFBI 0:4edb816d21e1 182
ICTFBI 0:4edb816d21e1 183 #if DNS_LOCAL_HOSTLIST
ICTFBI 0:4edb816d21e1 184
ICTFBI 0:4edb816d21e1 185 #if DNS_LOCAL_HOSTLIST_IS_DYNAMIC
ICTFBI 0:4edb816d21e1 186 /** Local host-list. For hostnames in this list, no
ICTFBI 0:4edb816d21e1 187 * external name resolution is performed */
ICTFBI 0:4edb816d21e1 188 static struct local_hostlist_entry *local_hostlist_dynamic;
ICTFBI 0:4edb816d21e1 189 #else /* DNS_LOCAL_HOSTLIST_IS_DYNAMIC */
ICTFBI 0:4edb816d21e1 190
ICTFBI 0:4edb816d21e1 191 /** Defining this allows the local_hostlist_static to be placed in a different
ICTFBI 0:4edb816d21e1 192 * linker section (e.g. FLASH) */
ICTFBI 0:4edb816d21e1 193 #ifndef DNS_LOCAL_HOSTLIST_STORAGE_PRE
ICTFBI 0:4edb816d21e1 194 #define DNS_LOCAL_HOSTLIST_STORAGE_PRE static
ICTFBI 0:4edb816d21e1 195 #endif /* DNS_LOCAL_HOSTLIST_STORAGE_PRE */
ICTFBI 0:4edb816d21e1 196 /** Defining this allows the local_hostlist_static to be placed in a different
ICTFBI 0:4edb816d21e1 197 * linker section (e.g. FLASH) */
ICTFBI 0:4edb816d21e1 198 #ifndef DNS_LOCAL_HOSTLIST_STORAGE_POST
ICTFBI 0:4edb816d21e1 199 #define DNS_LOCAL_HOSTLIST_STORAGE_POST
ICTFBI 0:4edb816d21e1 200 #endif /* DNS_LOCAL_HOSTLIST_STORAGE_POST */
ICTFBI 0:4edb816d21e1 201 DNS_LOCAL_HOSTLIST_STORAGE_PRE struct local_hostlist_entry local_hostlist_static[]
ICTFBI 0:4edb816d21e1 202 DNS_LOCAL_HOSTLIST_STORAGE_POST = DNS_LOCAL_HOSTLIST_INIT;
ICTFBI 0:4edb816d21e1 203
ICTFBI 0:4edb816d21e1 204 #endif /* DNS_LOCAL_HOSTLIST_IS_DYNAMIC */
ICTFBI 0:4edb816d21e1 205
ICTFBI 0:4edb816d21e1 206 static void dns_init_local();
ICTFBI 0:4edb816d21e1 207 #endif /* DNS_LOCAL_HOSTLIST */
ICTFBI 0:4edb816d21e1 208
ICTFBI 0:4edb816d21e1 209
ICTFBI 0:4edb816d21e1 210 /* forward declarations */
ICTFBI 0:4edb816d21e1 211 static void dns_recv(void *s, struct udp_pcb *pcb, struct pbuf *p, ip_addr_t *addr, u16_t port);
ICTFBI 0:4edb816d21e1 212 static void dns_check_entries(void);
ICTFBI 0:4edb816d21e1 213
ICTFBI 0:4edb816d21e1 214 /*-----------------------------------------------------------------------------
ICTFBI 0:4edb816d21e1 215 * Globales
ICTFBI 0:4edb816d21e1 216 *----------------------------------------------------------------------------*/
ICTFBI 0:4edb816d21e1 217
ICTFBI 0:4edb816d21e1 218 /* DNS variables */
ICTFBI 0:4edb816d21e1 219 static struct udp_pcb *dns_pcb;
ICTFBI 0:4edb816d21e1 220 static u8_t dns_seqno;
ICTFBI 0:4edb816d21e1 221 static struct dns_table_entry dns_table[DNS_TABLE_SIZE];
ICTFBI 0:4edb816d21e1 222 static ip_addr_t dns_servers[DNS_MAX_SERVERS];
ICTFBI 0:4edb816d21e1 223 /** Contiguous buffer for processing responses */
ICTFBI 0:4edb816d21e1 224 static u8_t dns_payload_buffer[LWIP_MEM_ALIGN_BUFFER(DNS_MSG_SIZE)];
ICTFBI 0:4edb816d21e1 225 static u8_t* dns_payload;
ICTFBI 0:4edb816d21e1 226
ICTFBI 0:4edb816d21e1 227 /**
ICTFBI 0:4edb816d21e1 228 * Initialize the resolver: set up the UDP pcb and configure the default server
ICTFBI 0:4edb816d21e1 229 * (DNS_SERVER_ADDRESS).
ICTFBI 0:4edb816d21e1 230 */
ICTFBI 0:4edb816d21e1 231 void
ICTFBI 0:4edb816d21e1 232 dns_init()
ICTFBI 0:4edb816d21e1 233 {
ICTFBI 0:4edb816d21e1 234 ip_addr_t dnsserver;
ICTFBI 0:4edb816d21e1 235
ICTFBI 0:4edb816d21e1 236 dns_payload = (u8_t *)LWIP_MEM_ALIGN(dns_payload_buffer);
ICTFBI 0:4edb816d21e1 237
ICTFBI 0:4edb816d21e1 238 /* initialize default DNS server address */
ICTFBI 0:4edb816d21e1 239 DNS_SERVER_ADDRESS(&dnsserver);
ICTFBI 0:4edb816d21e1 240
ICTFBI 0:4edb816d21e1 241 LWIP_DEBUGF(DNS_DEBUG, ("dns_init: initializing\n"));
ICTFBI 0:4edb816d21e1 242
ICTFBI 0:4edb816d21e1 243 /* if dns client not yet initialized... */
ICTFBI 0:4edb816d21e1 244 if (dns_pcb == NULL) {
ICTFBI 0:4edb816d21e1 245 dns_pcb = udp_new();
ICTFBI 0:4edb816d21e1 246
ICTFBI 0:4edb816d21e1 247 if (dns_pcb != NULL) {
ICTFBI 0:4edb816d21e1 248 /* initialize DNS table not needed (initialized to zero since it is a
ICTFBI 0:4edb816d21e1 249 * global variable) */
ICTFBI 0:4edb816d21e1 250 LWIP_ASSERT("For implicit initialization to work, DNS_STATE_UNUSED needs to be 0",
ICTFBI 0:4edb816d21e1 251 DNS_STATE_UNUSED == 0);
ICTFBI 0:4edb816d21e1 252
ICTFBI 0:4edb816d21e1 253 /* initialize DNS client */
ICTFBI 0:4edb816d21e1 254 udp_bind(dns_pcb, IP_ADDR_ANY, 0);
ICTFBI 0:4edb816d21e1 255 udp_recv(dns_pcb, dns_recv, NULL);
ICTFBI 0:4edb816d21e1 256
ICTFBI 0:4edb816d21e1 257 /* initialize default DNS primary server */
ICTFBI 0:4edb816d21e1 258 dns_setserver(0, &dnsserver);
ICTFBI 0:4edb816d21e1 259 }
ICTFBI 0:4edb816d21e1 260 }
ICTFBI 0:4edb816d21e1 261 #if DNS_LOCAL_HOSTLIST
ICTFBI 0:4edb816d21e1 262 dns_init_local();
ICTFBI 0:4edb816d21e1 263 #endif
ICTFBI 0:4edb816d21e1 264 }
ICTFBI 0:4edb816d21e1 265
ICTFBI 0:4edb816d21e1 266 /**
ICTFBI 0:4edb816d21e1 267 * Initialize one of the DNS servers.
ICTFBI 0:4edb816d21e1 268 *
ICTFBI 0:4edb816d21e1 269 * @param numdns the index of the DNS server to set must be < DNS_MAX_SERVERS
ICTFBI 0:4edb816d21e1 270 * @param dnsserver IP address of the DNS server to set
ICTFBI 0:4edb816d21e1 271 */
ICTFBI 0:4edb816d21e1 272 void
ICTFBI 0:4edb816d21e1 273 dns_setserver(u8_t numdns, ip_addr_t *dnsserver)
ICTFBI 0:4edb816d21e1 274 {
ICTFBI 0:4edb816d21e1 275 if ((numdns < DNS_MAX_SERVERS) && (dns_pcb != NULL) &&
ICTFBI 0:4edb816d21e1 276 (dnsserver != NULL) && !ip_addr_isany(dnsserver)) {
ICTFBI 0:4edb816d21e1 277 dns_servers[numdns] = (*dnsserver);
ICTFBI 0:4edb816d21e1 278 }
ICTFBI 0:4edb816d21e1 279 }
ICTFBI 0:4edb816d21e1 280
ICTFBI 0:4edb816d21e1 281 /**
ICTFBI 0:4edb816d21e1 282 * Obtain one of the currently configured DNS server.
ICTFBI 0:4edb816d21e1 283 *
ICTFBI 0:4edb816d21e1 284 * @param numdns the index of the DNS server
ICTFBI 0:4edb816d21e1 285 * @return IP address of the indexed DNS server or "ip_addr_any" if the DNS
ICTFBI 0:4edb816d21e1 286 * server has not been configured.
ICTFBI 0:4edb816d21e1 287 */
ICTFBI 0:4edb816d21e1 288 ip_addr_t
ICTFBI 0:4edb816d21e1 289 dns_getserver(u8_t numdns)
ICTFBI 0:4edb816d21e1 290 {
ICTFBI 0:4edb816d21e1 291 if (numdns < DNS_MAX_SERVERS) {
ICTFBI 0:4edb816d21e1 292 return dns_servers[numdns];
ICTFBI 0:4edb816d21e1 293 } else {
ICTFBI 0:4edb816d21e1 294 return *IP_ADDR_ANY;
ICTFBI 0:4edb816d21e1 295 }
ICTFBI 0:4edb816d21e1 296 }
ICTFBI 0:4edb816d21e1 297
ICTFBI 0:4edb816d21e1 298 /**
ICTFBI 0:4edb816d21e1 299 * The DNS resolver client timer - handle retries and timeouts and should
ICTFBI 0:4edb816d21e1 300 * be called every DNS_TMR_INTERVAL milliseconds (every second by default).
ICTFBI 0:4edb816d21e1 301 */
ICTFBI 0:4edb816d21e1 302 void
ICTFBI 0:4edb816d21e1 303 dns_tmr(void)
ICTFBI 0:4edb816d21e1 304 {
ICTFBI 0:4edb816d21e1 305 if (dns_pcb != NULL) {
ICTFBI 0:4edb816d21e1 306 LWIP_DEBUGF(DNS_DEBUG, ("dns_tmr: dns_check_entries\n"));
ICTFBI 0:4edb816d21e1 307 dns_check_entries();
ICTFBI 0:4edb816d21e1 308 }
ICTFBI 0:4edb816d21e1 309 }
ICTFBI 0:4edb816d21e1 310
ICTFBI 0:4edb816d21e1 311 #if DNS_LOCAL_HOSTLIST
ICTFBI 0:4edb816d21e1 312 static void
ICTFBI 0:4edb816d21e1 313 dns_init_local()
ICTFBI 0:4edb816d21e1 314 {
ICTFBI 0:4edb816d21e1 315 #if DNS_LOCAL_HOSTLIST_IS_DYNAMIC && defined(DNS_LOCAL_HOSTLIST_INIT)
ICTFBI 0:4edb816d21e1 316 int i;
ICTFBI 0:4edb816d21e1 317 struct local_hostlist_entry *entry;
ICTFBI 0:4edb816d21e1 318 /* Dynamic: copy entries from DNS_LOCAL_HOSTLIST_INIT to list */
ICTFBI 0:4edb816d21e1 319 struct local_hostlist_entry local_hostlist_init[] = DNS_LOCAL_HOSTLIST_INIT;
ICTFBI 0:4edb816d21e1 320 size_t namelen;
ICTFBI 0:4edb816d21e1 321 for (i = 0; i < sizeof(local_hostlist_init) / sizeof(struct local_hostlist_entry); i++) {
ICTFBI 0:4edb816d21e1 322 struct local_hostlist_entry *init_entry = &local_hostlist_init[i];
ICTFBI 0:4edb816d21e1 323 LWIP_ASSERT("invalid host name (NULL)", init_entry->name != NULL);
ICTFBI 0:4edb816d21e1 324 namelen = strlen(init_entry->name);
ICTFBI 0:4edb816d21e1 325 LWIP_ASSERT("namelen <= DNS_LOCAL_HOSTLIST_MAX_NAMELEN", namelen <= DNS_LOCAL_HOSTLIST_MAX_NAMELEN);
ICTFBI 0:4edb816d21e1 326 entry = (struct local_hostlist_entry *)memp_malloc(MEMP_LOCALHOSTLIST);
ICTFBI 0:4edb816d21e1 327 LWIP_ASSERT("mem-error in dns_init_local", entry != NULL);
ICTFBI 0:4edb816d21e1 328 if (entry != NULL) {
ICTFBI 0:4edb816d21e1 329 entry->name = (char*)entry + sizeof(struct local_hostlist_entry);
ICTFBI 0:4edb816d21e1 330 MEMCPY((char*)entry->name, init_entry->name, namelen);
ICTFBI 0:4edb816d21e1 331 ((char*)entry->name)[namelen] = 0;
ICTFBI 0:4edb816d21e1 332 entry->addr = init_entry->addr;
ICTFBI 0:4edb816d21e1 333 entry->next = local_hostlist_dynamic;
ICTFBI 0:4edb816d21e1 334 local_hostlist_dynamic = entry;
ICTFBI 0:4edb816d21e1 335 }
ICTFBI 0:4edb816d21e1 336 }
ICTFBI 0:4edb816d21e1 337 #endif /* DNS_LOCAL_HOSTLIST_IS_DYNAMIC && defined(DNS_LOCAL_HOSTLIST_INIT) */
ICTFBI 0:4edb816d21e1 338 }
ICTFBI 0:4edb816d21e1 339
ICTFBI 0:4edb816d21e1 340 /**
ICTFBI 0:4edb816d21e1 341 * Scans the local host-list for a hostname.
ICTFBI 0:4edb816d21e1 342 *
ICTFBI 0:4edb816d21e1 343 * @param hostname Hostname to look for in the local host-list
ICTFBI 0:4edb816d21e1 344 * @return The first IP address for the hostname in the local host-list or
ICTFBI 0:4edb816d21e1 345 * IPADDR_NONE if not found.
ICTFBI 0:4edb816d21e1 346 */
ICTFBI 0:4edb816d21e1 347 static u32_t
ICTFBI 0:4edb816d21e1 348 dns_lookup_local(const char *hostname)
ICTFBI 0:4edb816d21e1 349 {
ICTFBI 0:4edb816d21e1 350 #if DNS_LOCAL_HOSTLIST_IS_DYNAMIC
ICTFBI 0:4edb816d21e1 351 struct local_hostlist_entry *entry = local_hostlist_dynamic;
ICTFBI 0:4edb816d21e1 352 while(entry != NULL) {
ICTFBI 0:4edb816d21e1 353 if(strcmp(entry->name, hostname) == 0) {
ICTFBI 0:4edb816d21e1 354 return ip4_addr_get_u32(&entry->addr);
ICTFBI 0:4edb816d21e1 355 }
ICTFBI 0:4edb816d21e1 356 entry = entry->next;
ICTFBI 0:4edb816d21e1 357 }
ICTFBI 0:4edb816d21e1 358 #else /* DNS_LOCAL_HOSTLIST_IS_DYNAMIC */
ICTFBI 0:4edb816d21e1 359 int i;
ICTFBI 0:4edb816d21e1 360 for (i = 0; i < sizeof(local_hostlist_static) / sizeof(struct local_hostlist_entry); i++) {
ICTFBI 0:4edb816d21e1 361 if(strcmp(local_hostlist_static[i].name, hostname) == 0) {
ICTFBI 0:4edb816d21e1 362 return ip4_addr_get_u32(&local_hostlist_static[i].addr);
ICTFBI 0:4edb816d21e1 363 }
ICTFBI 0:4edb816d21e1 364 }
ICTFBI 0:4edb816d21e1 365 #endif /* DNS_LOCAL_HOSTLIST_IS_DYNAMIC */
ICTFBI 0:4edb816d21e1 366 return IPADDR_NONE;
ICTFBI 0:4edb816d21e1 367 }
ICTFBI 0:4edb816d21e1 368
ICTFBI 0:4edb816d21e1 369 #if DNS_LOCAL_HOSTLIST_IS_DYNAMIC
ICTFBI 0:4edb816d21e1 370 /** Remove all entries from the local host-list for a specific hostname
ICTFBI 0:4edb816d21e1 371 * and/or IP addess
ICTFBI 0:4edb816d21e1 372 *
ICTFBI 0:4edb816d21e1 373 * @param hostname hostname for which entries shall be removed from the local
ICTFBI 0:4edb816d21e1 374 * host-list
ICTFBI 0:4edb816d21e1 375 * @param addr address for which entries shall be removed from the local host-list
ICTFBI 0:4edb816d21e1 376 * @return the number of removed entries
ICTFBI 0:4edb816d21e1 377 */
ICTFBI 0:4edb816d21e1 378 int
ICTFBI 0:4edb816d21e1 379 dns_local_removehost(const char *hostname, const ip_addr_t *addr)
ICTFBI 0:4edb816d21e1 380 {
ICTFBI 0:4edb816d21e1 381 int removed = 0;
ICTFBI 0:4edb816d21e1 382 struct local_hostlist_entry *entry = local_hostlist_dynamic;
ICTFBI 0:4edb816d21e1 383 struct local_hostlist_entry *last_entry = NULL;
ICTFBI 0:4edb816d21e1 384 while (entry != NULL) {
ICTFBI 0:4edb816d21e1 385 if (((hostname == NULL) || !strcmp(entry->name, hostname)) &&
ICTFBI 0:4edb816d21e1 386 ((addr == NULL) || ip_addr_cmp(&entry->addr, addr))) {
ICTFBI 0:4edb816d21e1 387 struct local_hostlist_entry *free_entry;
ICTFBI 0:4edb816d21e1 388 if (last_entry != NULL) {
ICTFBI 0:4edb816d21e1 389 last_entry->next = entry->next;
ICTFBI 0:4edb816d21e1 390 } else {
ICTFBI 0:4edb816d21e1 391 local_hostlist_dynamic = entry->next;
ICTFBI 0:4edb816d21e1 392 }
ICTFBI 0:4edb816d21e1 393 free_entry = entry;
ICTFBI 0:4edb816d21e1 394 entry = entry->next;
ICTFBI 0:4edb816d21e1 395 memp_free(MEMP_LOCALHOSTLIST, free_entry);
ICTFBI 0:4edb816d21e1 396 removed++;
ICTFBI 0:4edb816d21e1 397 } else {
ICTFBI 0:4edb816d21e1 398 last_entry = entry;
ICTFBI 0:4edb816d21e1 399 entry = entry->next;
ICTFBI 0:4edb816d21e1 400 }
ICTFBI 0:4edb816d21e1 401 }
ICTFBI 0:4edb816d21e1 402 return removed;
ICTFBI 0:4edb816d21e1 403 }
ICTFBI 0:4edb816d21e1 404
ICTFBI 0:4edb816d21e1 405 /**
ICTFBI 0:4edb816d21e1 406 * Add a hostname/IP address pair to the local host-list.
ICTFBI 0:4edb816d21e1 407 * Duplicates are not checked.
ICTFBI 0:4edb816d21e1 408 *
ICTFBI 0:4edb816d21e1 409 * @param hostname hostname of the new entry
ICTFBI 0:4edb816d21e1 410 * @param addr IP address of the new entry
ICTFBI 0:4edb816d21e1 411 * @return ERR_OK if succeeded or ERR_MEM on memory error
ICTFBI 0:4edb816d21e1 412 */
ICTFBI 0:4edb816d21e1 413 err_t
ICTFBI 0:4edb816d21e1 414 dns_local_addhost(const char *hostname, const ip_addr_t *addr)
ICTFBI 0:4edb816d21e1 415 {
ICTFBI 0:4edb816d21e1 416 struct local_hostlist_entry *entry;
ICTFBI 0:4edb816d21e1 417 size_t namelen;
ICTFBI 0:4edb816d21e1 418 LWIP_ASSERT("invalid host name (NULL)", hostname != NULL);
ICTFBI 0:4edb816d21e1 419 namelen = strlen(hostname);
ICTFBI 0:4edb816d21e1 420 LWIP_ASSERT("namelen <= DNS_LOCAL_HOSTLIST_MAX_NAMELEN", namelen <= DNS_LOCAL_HOSTLIST_MAX_NAMELEN);
ICTFBI 0:4edb816d21e1 421 entry = (struct local_hostlist_entry *)memp_malloc(MEMP_LOCALHOSTLIST);
ICTFBI 0:4edb816d21e1 422 if (entry == NULL) {
ICTFBI 0:4edb816d21e1 423 return ERR_MEM;
ICTFBI 0:4edb816d21e1 424 }
ICTFBI 0:4edb816d21e1 425 entry->name = (char*)entry + sizeof(struct local_hostlist_entry);
ICTFBI 0:4edb816d21e1 426 MEMCPY((char*)entry->name, hostname, namelen);
ICTFBI 0:4edb816d21e1 427 ((char*)entry->name)[namelen] = 0;
ICTFBI 0:4edb816d21e1 428 ip_addr_copy(entry->addr, *addr);
ICTFBI 0:4edb816d21e1 429 entry->next = local_hostlist_dynamic;
ICTFBI 0:4edb816d21e1 430 local_hostlist_dynamic = entry;
ICTFBI 0:4edb816d21e1 431 return ERR_OK;
ICTFBI 0:4edb816d21e1 432 }
ICTFBI 0:4edb816d21e1 433 #endif /* DNS_LOCAL_HOSTLIST_IS_DYNAMIC*/
ICTFBI 0:4edb816d21e1 434 #endif /* DNS_LOCAL_HOSTLIST */
ICTFBI 0:4edb816d21e1 435
ICTFBI 0:4edb816d21e1 436 /**
ICTFBI 0:4edb816d21e1 437 * Look up a hostname in the array of known hostnames.
ICTFBI 0:4edb816d21e1 438 *
ICTFBI 0:4edb816d21e1 439 * @note This function only looks in the internal array of known
ICTFBI 0:4edb816d21e1 440 * hostnames, it does not send out a query for the hostname if none
ICTFBI 0:4edb816d21e1 441 * was found. The function dns_enqueue() can be used to send a query
ICTFBI 0:4edb816d21e1 442 * for a hostname.
ICTFBI 0:4edb816d21e1 443 *
ICTFBI 0:4edb816d21e1 444 * @param name the hostname to look up
ICTFBI 0:4edb816d21e1 445 * @return the hostname's IP address, as u32_t (instead of ip_addr_t to
ICTFBI 0:4edb816d21e1 446 * better check for failure: != IPADDR_NONE) or IPADDR_NONE if the hostname
ICTFBI 0:4edb816d21e1 447 * was not found in the cached dns_table.
ICTFBI 0:4edb816d21e1 448 */
ICTFBI 0:4edb816d21e1 449 static u32_t
ICTFBI 0:4edb816d21e1 450 dns_lookup(const char *name)
ICTFBI 0:4edb816d21e1 451 {
ICTFBI 0:4edb816d21e1 452 u8_t i;
ICTFBI 0:4edb816d21e1 453 #if DNS_LOCAL_HOSTLIST || defined(DNS_LOOKUP_LOCAL_EXTERN)
ICTFBI 0:4edb816d21e1 454 u32_t addr;
ICTFBI 0:4edb816d21e1 455 #endif /* DNS_LOCAL_HOSTLIST || defined(DNS_LOOKUP_LOCAL_EXTERN) */
ICTFBI 0:4edb816d21e1 456 #if DNS_LOCAL_HOSTLIST
ICTFBI 0:4edb816d21e1 457 if ((addr = dns_lookup_local(name)) != IPADDR_NONE) {
ICTFBI 0:4edb816d21e1 458 return addr;
ICTFBI 0:4edb816d21e1 459 }
ICTFBI 0:4edb816d21e1 460 #endif /* DNS_LOCAL_HOSTLIST */
ICTFBI 0:4edb816d21e1 461 #ifdef DNS_LOOKUP_LOCAL_EXTERN
ICTFBI 0:4edb816d21e1 462 if((addr = DNS_LOOKUP_LOCAL_EXTERN(name)) != IPADDR_NONE) {
ICTFBI 0:4edb816d21e1 463 return addr;
ICTFBI 0:4edb816d21e1 464 }
ICTFBI 0:4edb816d21e1 465 #endif /* DNS_LOOKUP_LOCAL_EXTERN */
ICTFBI 0:4edb816d21e1 466
ICTFBI 0:4edb816d21e1 467 /* Walk through name list, return entry if found. If not, return NULL. */
ICTFBI 0:4edb816d21e1 468 for (i = 0; i < DNS_TABLE_SIZE; ++i) {
ICTFBI 0:4edb816d21e1 469 if ((dns_table[i].state == DNS_STATE_DONE) &&
ICTFBI 0:4edb816d21e1 470 (strcmp(name, dns_table[i].name) == 0)) {
ICTFBI 0:4edb816d21e1 471 LWIP_DEBUGF(DNS_DEBUG, ("dns_lookup: \"%s\": found = ", name));
ICTFBI 0:4edb816d21e1 472 ip_addr_debug_print(DNS_DEBUG, &(dns_table[i].ipaddr));
ICTFBI 0:4edb816d21e1 473 LWIP_DEBUGF(DNS_DEBUG, ("\n"));
ICTFBI 0:4edb816d21e1 474 return ip4_addr_get_u32(&dns_table[i].ipaddr);
ICTFBI 0:4edb816d21e1 475 }
ICTFBI 0:4edb816d21e1 476 }
ICTFBI 0:4edb816d21e1 477
ICTFBI 0:4edb816d21e1 478 return IPADDR_NONE;
ICTFBI 0:4edb816d21e1 479 }
ICTFBI 0:4edb816d21e1 480
ICTFBI 0:4edb816d21e1 481 #if DNS_DOES_NAME_CHECK
ICTFBI 0:4edb816d21e1 482 /**
ICTFBI 0:4edb816d21e1 483 * Compare the "dotted" name "query" with the encoded name "response"
ICTFBI 0:4edb816d21e1 484 * to make sure an answer from the DNS server matches the current dns_table
ICTFBI 0:4edb816d21e1 485 * entry (otherwise, answers might arrive late for hostname not on the list
ICTFBI 0:4edb816d21e1 486 * any more).
ICTFBI 0:4edb816d21e1 487 *
ICTFBI 0:4edb816d21e1 488 * @param query hostname (not encoded) from the dns_table
ICTFBI 0:4edb816d21e1 489 * @param response encoded hostname in the DNS response
ICTFBI 0:4edb816d21e1 490 * @return 0: names equal; 1: names differ
ICTFBI 0:4edb816d21e1 491 */
ICTFBI 0:4edb816d21e1 492 static u8_t
ICTFBI 0:4edb816d21e1 493 dns_compare_name(unsigned char *query, unsigned char *response)
ICTFBI 0:4edb816d21e1 494 {
ICTFBI 0:4edb816d21e1 495 unsigned char n;
ICTFBI 0:4edb816d21e1 496
ICTFBI 0:4edb816d21e1 497 do {
ICTFBI 0:4edb816d21e1 498 n = *response++;
ICTFBI 0:4edb816d21e1 499 /** @see RFC 1035 - 4.1.4. Message compression */
ICTFBI 0:4edb816d21e1 500 if ((n & 0xc0) == 0xc0) {
ICTFBI 0:4edb816d21e1 501 /* Compressed name */
ICTFBI 0:4edb816d21e1 502 break;
ICTFBI 0:4edb816d21e1 503 } else {
ICTFBI 0:4edb816d21e1 504 /* Not compressed name */
ICTFBI 0:4edb816d21e1 505 while (n > 0) {
ICTFBI 0:4edb816d21e1 506 if ((*query) != (*response)) {
ICTFBI 0:4edb816d21e1 507 return 1;
ICTFBI 0:4edb816d21e1 508 }
ICTFBI 0:4edb816d21e1 509 ++response;
ICTFBI 0:4edb816d21e1 510 ++query;
ICTFBI 0:4edb816d21e1 511 --n;
ICTFBI 0:4edb816d21e1 512 };
ICTFBI 0:4edb816d21e1 513 ++query;
ICTFBI 0:4edb816d21e1 514 }
ICTFBI 0:4edb816d21e1 515 } while (*response != 0);
ICTFBI 0:4edb816d21e1 516
ICTFBI 0:4edb816d21e1 517 return 0;
ICTFBI 0:4edb816d21e1 518 }
ICTFBI 0:4edb816d21e1 519 #endif /* DNS_DOES_NAME_CHECK */
ICTFBI 0:4edb816d21e1 520
ICTFBI 0:4edb816d21e1 521 /**
ICTFBI 0:4edb816d21e1 522 * Walk through a compact encoded DNS name and return the end of the name.
ICTFBI 0:4edb816d21e1 523 *
ICTFBI 0:4edb816d21e1 524 * @param query encoded DNS name in the DNS server response
ICTFBI 0:4edb816d21e1 525 * @return end of the name
ICTFBI 0:4edb816d21e1 526 */
ICTFBI 0:4edb816d21e1 527 static unsigned char *
ICTFBI 0:4edb816d21e1 528 dns_parse_name(unsigned char *query)
ICTFBI 0:4edb816d21e1 529 {
ICTFBI 0:4edb816d21e1 530 unsigned char n;
ICTFBI 0:4edb816d21e1 531
ICTFBI 0:4edb816d21e1 532 do {
ICTFBI 0:4edb816d21e1 533 n = *query++;
ICTFBI 0:4edb816d21e1 534 /** @see RFC 1035 - 4.1.4. Message compression */
ICTFBI 0:4edb816d21e1 535 if ((n & 0xc0) == 0xc0) {
ICTFBI 0:4edb816d21e1 536 /* Compressed name */
ICTFBI 0:4edb816d21e1 537 break;
ICTFBI 0:4edb816d21e1 538 } else {
ICTFBI 0:4edb816d21e1 539 /* Not compressed name */
ICTFBI 0:4edb816d21e1 540 while (n > 0) {
ICTFBI 0:4edb816d21e1 541 ++query;
ICTFBI 0:4edb816d21e1 542 --n;
ICTFBI 0:4edb816d21e1 543 };
ICTFBI 0:4edb816d21e1 544 }
ICTFBI 0:4edb816d21e1 545 } while (*query != 0);
ICTFBI 0:4edb816d21e1 546
ICTFBI 0:4edb816d21e1 547 return query + 1;
ICTFBI 0:4edb816d21e1 548 }
ICTFBI 0:4edb816d21e1 549
ICTFBI 0:4edb816d21e1 550 /**
ICTFBI 0:4edb816d21e1 551 * Send a DNS query packet.
ICTFBI 0:4edb816d21e1 552 *
ICTFBI 0:4edb816d21e1 553 * @param numdns index of the DNS server in the dns_servers table
ICTFBI 0:4edb816d21e1 554 * @param name hostname to query
ICTFBI 0:4edb816d21e1 555 * @param id index of the hostname in dns_table, used as transaction ID in the
ICTFBI 0:4edb816d21e1 556 * DNS query packet
ICTFBI 0:4edb816d21e1 557 * @return ERR_OK if packet is sent; an err_t indicating the problem otherwise
ICTFBI 0:4edb816d21e1 558 */
ICTFBI 0:4edb816d21e1 559 static err_t
ICTFBI 0:4edb816d21e1 560 dns_send(u8_t numdns, const char* name, u8_t id)
ICTFBI 0:4edb816d21e1 561 {
ICTFBI 0:4edb816d21e1 562 err_t err;
ICTFBI 0:4edb816d21e1 563 struct dns_hdr *hdr;
ICTFBI 0:4edb816d21e1 564 struct dns_query qry;
ICTFBI 0:4edb816d21e1 565 struct pbuf *p;
ICTFBI 0:4edb816d21e1 566 char *query, *nptr;
ICTFBI 0:4edb816d21e1 567 const char *pHostname;
ICTFBI 0:4edb816d21e1 568 u8_t n;
ICTFBI 0:4edb816d21e1 569
ICTFBI 0:4edb816d21e1 570 LWIP_DEBUGF(DNS_DEBUG, ("dns_send: dns_servers[%"U16_F"] \"%s\": request\n",
ICTFBI 0:4edb816d21e1 571 (u16_t)(numdns), name));
ICTFBI 0:4edb816d21e1 572 LWIP_ASSERT("dns server out of array", numdns < DNS_MAX_SERVERS);
ICTFBI 0:4edb816d21e1 573 LWIP_ASSERT("dns server has no IP address set", !ip_addr_isany(&dns_servers[numdns]));
ICTFBI 0:4edb816d21e1 574
ICTFBI 0:4edb816d21e1 575 /* if here, we have either a new query or a retry on a previous query to process */
ICTFBI 0:4edb816d21e1 576 p = pbuf_alloc(PBUF_TRANSPORT, SIZEOF_DNS_HDR + DNS_MAX_NAME_LENGTH +
ICTFBI 0:4edb816d21e1 577 SIZEOF_DNS_QUERY, PBUF_RAM);
ICTFBI 0:4edb816d21e1 578 if (p != NULL) {
ICTFBI 0:4edb816d21e1 579 LWIP_ASSERT("pbuf must be in one piece", p->next == NULL);
ICTFBI 0:4edb816d21e1 580 /* fill dns header */
ICTFBI 0:4edb816d21e1 581 hdr = (struct dns_hdr*)p->payload;
ICTFBI 0:4edb816d21e1 582 memset(hdr, 0, SIZEOF_DNS_HDR);
ICTFBI 0:4edb816d21e1 583 hdr->id = htons(id);
ICTFBI 0:4edb816d21e1 584 hdr->flags1 = DNS_FLAG1_RD;
ICTFBI 0:4edb816d21e1 585 hdr->numquestions = PP_HTONS(1);
ICTFBI 0:4edb816d21e1 586 query = (char*)hdr + SIZEOF_DNS_HDR;
ICTFBI 0:4edb816d21e1 587 pHostname = name;
ICTFBI 0:4edb816d21e1 588 --pHostname;
ICTFBI 0:4edb816d21e1 589
ICTFBI 0:4edb816d21e1 590 /* convert hostname into suitable query format. */
ICTFBI 0:4edb816d21e1 591 do {
ICTFBI 0:4edb816d21e1 592 ++pHostname;
ICTFBI 0:4edb816d21e1 593 nptr = query;
ICTFBI 0:4edb816d21e1 594 ++query;
ICTFBI 0:4edb816d21e1 595 for(n = 0; *pHostname != '.' && *pHostname != 0; ++pHostname) {
ICTFBI 0:4edb816d21e1 596 *query = *pHostname;
ICTFBI 0:4edb816d21e1 597 ++query;
ICTFBI 0:4edb816d21e1 598 ++n;
ICTFBI 0:4edb816d21e1 599 }
ICTFBI 0:4edb816d21e1 600 *nptr = n;
ICTFBI 0:4edb816d21e1 601 } while(*pHostname != 0);
ICTFBI 0:4edb816d21e1 602 *query++='\0';
ICTFBI 0:4edb816d21e1 603
ICTFBI 0:4edb816d21e1 604 /* fill dns query */
ICTFBI 0:4edb816d21e1 605 qry.type = PP_HTONS(DNS_RRTYPE_A);
ICTFBI 0:4edb816d21e1 606 qry.cls = PP_HTONS(DNS_RRCLASS_IN);
ICTFBI 0:4edb816d21e1 607 SMEMCPY(query, &qry, SIZEOF_DNS_QUERY);
ICTFBI 0:4edb816d21e1 608
ICTFBI 0:4edb816d21e1 609 /* resize pbuf to the exact dns query */
ICTFBI 0:4edb816d21e1 610 pbuf_realloc(p, (u16_t)((query + SIZEOF_DNS_QUERY) - ((char*)(p->payload))));
ICTFBI 0:4edb816d21e1 611
ICTFBI 0:4edb816d21e1 612 /* connect to the server for faster receiving */
ICTFBI 0:4edb816d21e1 613 udp_connect(dns_pcb, &dns_servers[numdns], DNS_SERVER_PORT);
ICTFBI 0:4edb816d21e1 614 /* send dns packet */
ICTFBI 0:4edb816d21e1 615 err = udp_sendto(dns_pcb, p, &dns_servers[numdns], DNS_SERVER_PORT);
ICTFBI 0:4edb816d21e1 616
ICTFBI 0:4edb816d21e1 617 /* free pbuf */
ICTFBI 0:4edb816d21e1 618 pbuf_free(p);
ICTFBI 0:4edb816d21e1 619 } else {
ICTFBI 0:4edb816d21e1 620 err = ERR_MEM;
ICTFBI 0:4edb816d21e1 621 }
ICTFBI 0:4edb816d21e1 622
ICTFBI 0:4edb816d21e1 623 return err;
ICTFBI 0:4edb816d21e1 624 }
ICTFBI 0:4edb816d21e1 625
ICTFBI 0:4edb816d21e1 626 /**
ICTFBI 0:4edb816d21e1 627 * dns_check_entry() - see if pEntry has not yet been queried and, if so, sends out a query.
ICTFBI 0:4edb816d21e1 628 * Check an entry in the dns_table:
ICTFBI 0:4edb816d21e1 629 * - send out query for new entries
ICTFBI 0:4edb816d21e1 630 * - retry old pending entries on timeout (also with different servers)
ICTFBI 0:4edb816d21e1 631 * - remove completed entries from the table if their TTL has expired
ICTFBI 0:4edb816d21e1 632 *
ICTFBI 0:4edb816d21e1 633 * @param i index of the dns_table entry to check
ICTFBI 0:4edb816d21e1 634 */
ICTFBI 0:4edb816d21e1 635 static void
ICTFBI 0:4edb816d21e1 636 dns_check_entry(u8_t i)
ICTFBI 0:4edb816d21e1 637 {
ICTFBI 0:4edb816d21e1 638 err_t err;
ICTFBI 0:4edb816d21e1 639 struct dns_table_entry *pEntry = &dns_table[i];
ICTFBI 0:4edb816d21e1 640
ICTFBI 0:4edb816d21e1 641 LWIP_ASSERT("array index out of bounds", i < DNS_TABLE_SIZE);
ICTFBI 0:4edb816d21e1 642
ICTFBI 0:4edb816d21e1 643 switch(pEntry->state) {
ICTFBI 0:4edb816d21e1 644
ICTFBI 0:4edb816d21e1 645 case DNS_STATE_NEW: {
ICTFBI 0:4edb816d21e1 646 /* initialize new entry */
ICTFBI 0:4edb816d21e1 647 pEntry->state = DNS_STATE_ASKING;
ICTFBI 0:4edb816d21e1 648 pEntry->numdns = 0;
ICTFBI 0:4edb816d21e1 649 pEntry->tmr = 1;
ICTFBI 0:4edb816d21e1 650 pEntry->retries = 0;
ICTFBI 0:4edb816d21e1 651
ICTFBI 0:4edb816d21e1 652 /* send DNS packet for this entry */
ICTFBI 0:4edb816d21e1 653 err = dns_send(pEntry->numdns, pEntry->name, i);
ICTFBI 0:4edb816d21e1 654 if (err != ERR_OK) {
ICTFBI 0:4edb816d21e1 655 LWIP_DEBUGF(DNS_DEBUG | LWIP_DBG_LEVEL_WARNING,
ICTFBI 0:4edb816d21e1 656 ("dns_send returned error: %d\n", err)); //FIX DG, lwip_strerr is part of lwip/api
ICTFBI 0:4edb816d21e1 657 }
ICTFBI 0:4edb816d21e1 658 break;
ICTFBI 0:4edb816d21e1 659 }
ICTFBI 0:4edb816d21e1 660
ICTFBI 0:4edb816d21e1 661 case DNS_STATE_ASKING: {
ICTFBI 0:4edb816d21e1 662 if (--pEntry->tmr == 0) {
ICTFBI 0:4edb816d21e1 663 if (++pEntry->retries == DNS_MAX_RETRIES) {
ICTFBI 0:4edb816d21e1 664 if ((pEntry->numdns+1<DNS_MAX_SERVERS) && !ip_addr_isany(&dns_servers[pEntry->numdns+1])) {
ICTFBI 0:4edb816d21e1 665 /* change of server */
ICTFBI 0:4edb816d21e1 666 pEntry->numdns++;
ICTFBI 0:4edb816d21e1 667 pEntry->tmr = 1;
ICTFBI 0:4edb816d21e1 668 pEntry->retries = 0;
ICTFBI 0:4edb816d21e1 669 break;
ICTFBI 0:4edb816d21e1 670 } else {
ICTFBI 0:4edb816d21e1 671 LWIP_DEBUGF(DNS_DEBUG, ("dns_check_entry: \"%s\": timeout\n", pEntry->name));
ICTFBI 0:4edb816d21e1 672 /* call specified callback function if provided */
ICTFBI 0:4edb816d21e1 673 if (pEntry->found)
ICTFBI 0:4edb816d21e1 674 (*pEntry->found)(pEntry->name, NULL, pEntry->arg);
ICTFBI 0:4edb816d21e1 675 /* flush this entry */
ICTFBI 0:4edb816d21e1 676 pEntry->state = DNS_STATE_UNUSED;
ICTFBI 0:4edb816d21e1 677 pEntry->found = NULL;
ICTFBI 0:4edb816d21e1 678 break;
ICTFBI 0:4edb816d21e1 679 }
ICTFBI 0:4edb816d21e1 680 }
ICTFBI 0:4edb816d21e1 681
ICTFBI 0:4edb816d21e1 682 /* wait longer for the next retry */
ICTFBI 0:4edb816d21e1 683 pEntry->tmr = pEntry->retries;
ICTFBI 0:4edb816d21e1 684
ICTFBI 0:4edb816d21e1 685 /* send DNS packet for this entry */
ICTFBI 0:4edb816d21e1 686 err = dns_send(pEntry->numdns, pEntry->name, i);
ICTFBI 0:4edb816d21e1 687 if (err != ERR_OK) {
ICTFBI 0:4edb816d21e1 688 LWIP_DEBUGF(DNS_DEBUG | LWIP_DBG_LEVEL_WARNING,
ICTFBI 0:4edb816d21e1 689 ("dns_send returned error: %d\n", err)); //FIX DG, lwip_strerr is part of lwip/api
ICTFBI 0:4edb816d21e1 690 }
ICTFBI 0:4edb816d21e1 691 }
ICTFBI 0:4edb816d21e1 692 break;
ICTFBI 0:4edb816d21e1 693 }
ICTFBI 0:4edb816d21e1 694
ICTFBI 0:4edb816d21e1 695 case DNS_STATE_DONE: {
ICTFBI 0:4edb816d21e1 696 /* if the time to live is nul */
ICTFBI 0:4edb816d21e1 697 if (--pEntry->ttl == 0) {
ICTFBI 0:4edb816d21e1 698 LWIP_DEBUGF(DNS_DEBUG, ("dns_check_entry: \"%s\": flush\n", pEntry->name));
ICTFBI 0:4edb816d21e1 699 /* flush this entry */
ICTFBI 0:4edb816d21e1 700 pEntry->state = DNS_STATE_UNUSED;
ICTFBI 0:4edb816d21e1 701 pEntry->found = NULL;
ICTFBI 0:4edb816d21e1 702 }
ICTFBI 0:4edb816d21e1 703 break;
ICTFBI 0:4edb816d21e1 704 }
ICTFBI 0:4edb816d21e1 705 case DNS_STATE_UNUSED:
ICTFBI 0:4edb816d21e1 706 /* nothing to do */
ICTFBI 0:4edb816d21e1 707 break;
ICTFBI 0:4edb816d21e1 708 default:
ICTFBI 0:4edb816d21e1 709 LWIP_ASSERT("unknown dns_table entry state:", 0);
ICTFBI 0:4edb816d21e1 710 break;
ICTFBI 0:4edb816d21e1 711 }
ICTFBI 0:4edb816d21e1 712 }
ICTFBI 0:4edb816d21e1 713
ICTFBI 0:4edb816d21e1 714 /**
ICTFBI 0:4edb816d21e1 715 * Call dns_check_entry for each entry in dns_table - check all entries.
ICTFBI 0:4edb816d21e1 716 */
ICTFBI 0:4edb816d21e1 717 static void
ICTFBI 0:4edb816d21e1 718 dns_check_entries(void)
ICTFBI 0:4edb816d21e1 719 {
ICTFBI 0:4edb816d21e1 720 u8_t i;
ICTFBI 0:4edb816d21e1 721
ICTFBI 0:4edb816d21e1 722 for (i = 0; i < DNS_TABLE_SIZE; ++i) {
ICTFBI 0:4edb816d21e1 723 dns_check_entry(i);
ICTFBI 0:4edb816d21e1 724 }
ICTFBI 0:4edb816d21e1 725 }
ICTFBI 0:4edb816d21e1 726
ICTFBI 0:4edb816d21e1 727 /**
ICTFBI 0:4edb816d21e1 728 * Receive input function for DNS response packets arriving for the dns UDP pcb.
ICTFBI 0:4edb816d21e1 729 *
ICTFBI 0:4edb816d21e1 730 * @params see udp.h
ICTFBI 0:4edb816d21e1 731 */
ICTFBI 0:4edb816d21e1 732 static void
ICTFBI 0:4edb816d21e1 733 dns_recv(void *arg, struct udp_pcb *pcb, struct pbuf *p, ip_addr_t *addr, u16_t port)
ICTFBI 0:4edb816d21e1 734 {
ICTFBI 0:4edb816d21e1 735 u16_t i;
ICTFBI 0:4edb816d21e1 736 char *pHostname;
ICTFBI 0:4edb816d21e1 737 struct dns_hdr *hdr;
ICTFBI 0:4edb816d21e1 738 struct dns_answer ans;
ICTFBI 0:4edb816d21e1 739 struct dns_table_entry *pEntry;
ICTFBI 0:4edb816d21e1 740 u16_t nquestions, nanswers;
ICTFBI 0:4edb816d21e1 741
ICTFBI 0:4edb816d21e1 742 LWIP_UNUSED_ARG(arg);
ICTFBI 0:4edb816d21e1 743 LWIP_UNUSED_ARG(pcb);
ICTFBI 0:4edb816d21e1 744 LWIP_UNUSED_ARG(addr);
ICTFBI 0:4edb816d21e1 745 LWIP_UNUSED_ARG(port);
ICTFBI 0:4edb816d21e1 746
ICTFBI 0:4edb816d21e1 747 /* is the dns message too big ? */
ICTFBI 0:4edb816d21e1 748 if (p->tot_len > DNS_MSG_SIZE) {
ICTFBI 0:4edb816d21e1 749 LWIP_DEBUGF(DNS_DEBUG, ("dns_recv: pbuf too big\n"));
ICTFBI 0:4edb816d21e1 750 /* free pbuf and return */
ICTFBI 0:4edb816d21e1 751 goto memerr;
ICTFBI 0:4edb816d21e1 752 }
ICTFBI 0:4edb816d21e1 753
ICTFBI 0:4edb816d21e1 754 /* is the dns message big enough ? */
ICTFBI 0:4edb816d21e1 755 if (p->tot_len < (SIZEOF_DNS_HDR + SIZEOF_DNS_QUERY + SIZEOF_DNS_ANSWER)) {
ICTFBI 0:4edb816d21e1 756 LWIP_DEBUGF(DNS_DEBUG, ("dns_recv: pbuf too small\n"));
ICTFBI 0:4edb816d21e1 757 /* free pbuf and return */
ICTFBI 0:4edb816d21e1 758 goto memerr;
ICTFBI 0:4edb816d21e1 759 }
ICTFBI 0:4edb816d21e1 760
ICTFBI 0:4edb816d21e1 761 /* copy dns payload inside static buffer for processing */
ICTFBI 0:4edb816d21e1 762 if (pbuf_copy_partial(p, dns_payload, p->tot_len, 0) == p->tot_len) {
ICTFBI 0:4edb816d21e1 763 /* The ID in the DNS header should be our entry into the name table. */
ICTFBI 0:4edb816d21e1 764 hdr = (struct dns_hdr*)dns_payload;
ICTFBI 0:4edb816d21e1 765 i = htons(hdr->id);
ICTFBI 0:4edb816d21e1 766 if (i < DNS_TABLE_SIZE) {
ICTFBI 0:4edb816d21e1 767 pEntry = &dns_table[i];
ICTFBI 0:4edb816d21e1 768 if(pEntry->state == DNS_STATE_ASKING) {
ICTFBI 0:4edb816d21e1 769 /* This entry is now completed. */
ICTFBI 0:4edb816d21e1 770 pEntry->state = DNS_STATE_DONE;
ICTFBI 0:4edb816d21e1 771 pEntry->err = hdr->flags2 & DNS_FLAG2_ERR_MASK;
ICTFBI 0:4edb816d21e1 772
ICTFBI 0:4edb816d21e1 773 /* We only care about the question(s) and the answers. The authrr
ICTFBI 0:4edb816d21e1 774 and the extrarr are simply discarded. */
ICTFBI 0:4edb816d21e1 775 nquestions = htons(hdr->numquestions);
ICTFBI 0:4edb816d21e1 776 nanswers = htons(hdr->numanswers);
ICTFBI 0:4edb816d21e1 777
ICTFBI 0:4edb816d21e1 778 /* Check for error. If so, call callback to inform. */
ICTFBI 0:4edb816d21e1 779 if (((hdr->flags1 & DNS_FLAG1_RESPONSE) == 0) || (pEntry->err != 0) || (nquestions != 1)) {
ICTFBI 0:4edb816d21e1 780 LWIP_DEBUGF(DNS_DEBUG, ("dns_recv: \"%s\": error in flags\n", pEntry->name));
ICTFBI 0:4edb816d21e1 781 /* call callback to indicate error, clean up memory and return */
ICTFBI 0:4edb816d21e1 782 goto responseerr;
ICTFBI 0:4edb816d21e1 783 }
ICTFBI 0:4edb816d21e1 784
ICTFBI 0:4edb816d21e1 785 #if DNS_DOES_NAME_CHECK
ICTFBI 0:4edb816d21e1 786 /* Check if the name in the "question" part match with the name in the entry. */
ICTFBI 0:4edb816d21e1 787 if (dns_compare_name((unsigned char *)(pEntry->name), (unsigned char *)dns_payload + SIZEOF_DNS_HDR) != 0) {
ICTFBI 0:4edb816d21e1 788 LWIP_DEBUGF(DNS_DEBUG, ("dns_recv: \"%s\": response not match to query\n", pEntry->name));
ICTFBI 0:4edb816d21e1 789 /* call callback to indicate error, clean up memory and return */
ICTFBI 0:4edb816d21e1 790 goto responseerr;
ICTFBI 0:4edb816d21e1 791 }
ICTFBI 0:4edb816d21e1 792 #endif /* DNS_DOES_NAME_CHECK */
ICTFBI 0:4edb816d21e1 793
ICTFBI 0:4edb816d21e1 794 /* Skip the name in the "question" part */
ICTFBI 0:4edb816d21e1 795 pHostname = (char *) dns_parse_name((unsigned char *)dns_payload + SIZEOF_DNS_HDR) + SIZEOF_DNS_QUERY;
ICTFBI 0:4edb816d21e1 796
ICTFBI 0:4edb816d21e1 797 while (nanswers > 0) {
ICTFBI 0:4edb816d21e1 798 /* skip answer resource record's host name */
ICTFBI 0:4edb816d21e1 799 pHostname = (char *) dns_parse_name((unsigned char *)pHostname);
ICTFBI 0:4edb816d21e1 800
ICTFBI 0:4edb816d21e1 801 /* Check for IP address type and Internet class. Others are discarded. */
ICTFBI 0:4edb816d21e1 802 SMEMCPY(&ans, pHostname, SIZEOF_DNS_ANSWER);
ICTFBI 0:4edb816d21e1 803 if((ans.type == PP_HTONS(DNS_RRTYPE_A)) && (ans.cls == PP_HTONS(DNS_RRCLASS_IN)) &&
ICTFBI 0:4edb816d21e1 804 (ans.len == PP_HTONS(sizeof(ip_addr_t))) ) {
ICTFBI 0:4edb816d21e1 805 /* read the answer resource record's TTL, and maximize it if needed */
ICTFBI 0:4edb816d21e1 806 pEntry->ttl = ntohl(ans.ttl);
ICTFBI 0:4edb816d21e1 807 if (pEntry->ttl > DNS_MAX_TTL) {
ICTFBI 0:4edb816d21e1 808 pEntry->ttl = DNS_MAX_TTL;
ICTFBI 0:4edb816d21e1 809 }
ICTFBI 0:4edb816d21e1 810 /* read the IP address after answer resource record's header */
ICTFBI 0:4edb816d21e1 811 SMEMCPY(&(pEntry->ipaddr), (pHostname+SIZEOF_DNS_ANSWER), sizeof(ip_addr_t));
ICTFBI 0:4edb816d21e1 812 LWIP_DEBUGF(DNS_DEBUG, ("dns_recv: \"%s\": response = ", pEntry->name));
ICTFBI 0:4edb816d21e1 813 ip_addr_debug_print(DNS_DEBUG, (&(pEntry->ipaddr)));
ICTFBI 0:4edb816d21e1 814 LWIP_DEBUGF(DNS_DEBUG, ("\n"));
ICTFBI 0:4edb816d21e1 815 /* call specified callback function if provided */
ICTFBI 0:4edb816d21e1 816 if (pEntry->found) {
ICTFBI 0:4edb816d21e1 817 (*pEntry->found)(pEntry->name, &pEntry->ipaddr, pEntry->arg);
ICTFBI 0:4edb816d21e1 818 }
ICTFBI 0:4edb816d21e1 819 /* deallocate memory and return */
ICTFBI 0:4edb816d21e1 820 goto memerr;
ICTFBI 0:4edb816d21e1 821 } else {
ICTFBI 0:4edb816d21e1 822 pHostname = pHostname + SIZEOF_DNS_ANSWER + htons(ans.len);
ICTFBI 0:4edb816d21e1 823 }
ICTFBI 0:4edb816d21e1 824 --nanswers;
ICTFBI 0:4edb816d21e1 825 }
ICTFBI 0:4edb816d21e1 826 LWIP_DEBUGF(DNS_DEBUG, ("dns_recv: \"%s\": error in response\n", pEntry->name));
ICTFBI 0:4edb816d21e1 827 /* call callback to indicate error, clean up memory and return */
ICTFBI 0:4edb816d21e1 828 goto responseerr;
ICTFBI 0:4edb816d21e1 829 }
ICTFBI 0:4edb816d21e1 830 }
ICTFBI 0:4edb816d21e1 831 }
ICTFBI 0:4edb816d21e1 832
ICTFBI 0:4edb816d21e1 833 /* deallocate memory and return */
ICTFBI 0:4edb816d21e1 834 goto memerr;
ICTFBI 0:4edb816d21e1 835
ICTFBI 0:4edb816d21e1 836 responseerr:
ICTFBI 0:4edb816d21e1 837 /* ERROR: call specified callback function with NULL as name to indicate an error */
ICTFBI 0:4edb816d21e1 838 if (pEntry->found) {
ICTFBI 0:4edb816d21e1 839 (*pEntry->found)(pEntry->name, NULL, pEntry->arg);
ICTFBI 0:4edb816d21e1 840 }
ICTFBI 0:4edb816d21e1 841 /* flush this entry */
ICTFBI 0:4edb816d21e1 842 pEntry->state = DNS_STATE_UNUSED;
ICTFBI 0:4edb816d21e1 843 pEntry->found = NULL;
ICTFBI 0:4edb816d21e1 844
ICTFBI 0:4edb816d21e1 845 memerr:
ICTFBI 0:4edb816d21e1 846 /* free pbuf */
ICTFBI 0:4edb816d21e1 847 pbuf_free(p);
ICTFBI 0:4edb816d21e1 848 return;
ICTFBI 0:4edb816d21e1 849 }
ICTFBI 0:4edb816d21e1 850
ICTFBI 0:4edb816d21e1 851 /**
ICTFBI 0:4edb816d21e1 852 * Queues a new hostname to resolve and sends out a DNS query for that hostname
ICTFBI 0:4edb816d21e1 853 *
ICTFBI 0:4edb816d21e1 854 * @param name the hostname that is to be queried
ICTFBI 0:4edb816d21e1 855 * @param found a callback founction to be called on success, failure or timeout
ICTFBI 0:4edb816d21e1 856 * @param callback_arg argument to pass to the callback function
ICTFBI 0:4edb816d21e1 857 * @return @return a err_t return code.
ICTFBI 0:4edb816d21e1 858 */
ICTFBI 0:4edb816d21e1 859 static err_t
ICTFBI 0:4edb816d21e1 860 dns_enqueue(const char *name, dns_found_callback found, void *callback_arg)
ICTFBI 0:4edb816d21e1 861 {
ICTFBI 0:4edb816d21e1 862 u8_t i;
ICTFBI 0:4edb816d21e1 863 u8_t lseq, lseqi;
ICTFBI 0:4edb816d21e1 864 struct dns_table_entry *pEntry = NULL;
ICTFBI 0:4edb816d21e1 865 size_t namelen;
ICTFBI 0:4edb816d21e1 866
ICTFBI 0:4edb816d21e1 867 /* search an unused entry, or the oldest one */
ICTFBI 0:4edb816d21e1 868 lseq = lseqi = 0;
ICTFBI 0:4edb816d21e1 869 for (i = 0; i < DNS_TABLE_SIZE; ++i) {
ICTFBI 0:4edb816d21e1 870 pEntry = &dns_table[i];
ICTFBI 0:4edb816d21e1 871 /* is it an unused entry ? */
ICTFBI 0:4edb816d21e1 872 if (pEntry->state == DNS_STATE_UNUSED)
ICTFBI 0:4edb816d21e1 873 break;
ICTFBI 0:4edb816d21e1 874
ICTFBI 0:4edb816d21e1 875 /* check if this is the oldest completed entry */
ICTFBI 0:4edb816d21e1 876 if (pEntry->state == DNS_STATE_DONE) {
ICTFBI 0:4edb816d21e1 877 if ((dns_seqno - pEntry->seqno) > lseq) {
ICTFBI 0:4edb816d21e1 878 lseq = dns_seqno - pEntry->seqno;
ICTFBI 0:4edb816d21e1 879 lseqi = i;
ICTFBI 0:4edb816d21e1 880 }
ICTFBI 0:4edb816d21e1 881 }
ICTFBI 0:4edb816d21e1 882 }
ICTFBI 0:4edb816d21e1 883
ICTFBI 0:4edb816d21e1 884 /* if we don't have found an unused entry, use the oldest completed one */
ICTFBI 0:4edb816d21e1 885 if (i == DNS_TABLE_SIZE) {
ICTFBI 0:4edb816d21e1 886 if ((lseqi >= DNS_TABLE_SIZE) || (dns_table[lseqi].state != DNS_STATE_DONE)) {
ICTFBI 0:4edb816d21e1 887 /* no entry can't be used now, table is full */
ICTFBI 0:4edb816d21e1 888 LWIP_DEBUGF(DNS_DEBUG, ("dns_enqueue: \"%s\": DNS entries table is full\n", name));
ICTFBI 0:4edb816d21e1 889 return ERR_MEM;
ICTFBI 0:4edb816d21e1 890 } else {
ICTFBI 0:4edb816d21e1 891 /* use the oldest completed one */
ICTFBI 0:4edb816d21e1 892 i = lseqi;
ICTFBI 0:4edb816d21e1 893 pEntry = &dns_table[i];
ICTFBI 0:4edb816d21e1 894 }
ICTFBI 0:4edb816d21e1 895 }
ICTFBI 0:4edb816d21e1 896
ICTFBI 0:4edb816d21e1 897 /* use this entry */
ICTFBI 0:4edb816d21e1 898 LWIP_DEBUGF(DNS_DEBUG, ("dns_enqueue: \"%s\": use DNS entry %"U16_F"\n", name, (u16_t)(i)));
ICTFBI 0:4edb816d21e1 899
ICTFBI 0:4edb816d21e1 900 /* fill the entry */
ICTFBI 0:4edb816d21e1 901 pEntry->state = DNS_STATE_NEW;
ICTFBI 0:4edb816d21e1 902 pEntry->seqno = dns_seqno++;
ICTFBI 0:4edb816d21e1 903 pEntry->found = found;
ICTFBI 0:4edb816d21e1 904 pEntry->arg = callback_arg;
ICTFBI 0:4edb816d21e1 905 namelen = LWIP_MIN(strlen(name), DNS_MAX_NAME_LENGTH-1);
ICTFBI 0:4edb816d21e1 906 MEMCPY(pEntry->name, name, namelen);
ICTFBI 0:4edb816d21e1 907 pEntry->name[namelen] = 0;
ICTFBI 0:4edb816d21e1 908
ICTFBI 0:4edb816d21e1 909 /* force to send query without waiting timer */
ICTFBI 0:4edb816d21e1 910 dns_check_entry(i);
ICTFBI 0:4edb816d21e1 911
ICTFBI 0:4edb816d21e1 912 /* dns query is enqueued */
ICTFBI 0:4edb816d21e1 913 return ERR_INPROGRESS;
ICTFBI 0:4edb816d21e1 914 }
ICTFBI 0:4edb816d21e1 915
ICTFBI 0:4edb816d21e1 916 /**
ICTFBI 0:4edb816d21e1 917 * Resolve a hostname (string) into an IP address.
ICTFBI 0:4edb816d21e1 918 * NON-BLOCKING callback version for use with raw API!!!
ICTFBI 0:4edb816d21e1 919 *
ICTFBI 0:4edb816d21e1 920 * Returns immediately with one of err_t return codes:
ICTFBI 0:4edb816d21e1 921 * - ERR_OK if hostname is a valid IP address string or the host
ICTFBI 0:4edb816d21e1 922 * name is already in the local names table.
ICTFBI 0:4edb816d21e1 923 * - ERR_INPROGRESS enqueue a request to be sent to the DNS server
ICTFBI 0:4edb816d21e1 924 * for resolution if no errors are present.
ICTFBI 0:4edb816d21e1 925 *
ICTFBI 0:4edb816d21e1 926 * @param hostname the hostname that is to be queried
ICTFBI 0:4edb816d21e1 927 * @param addr pointer to a ip_addr_t where to store the address if it is already
ICTFBI 0:4edb816d21e1 928 * cached in the dns_table (only valid if ERR_OK is returned!)
ICTFBI 0:4edb816d21e1 929 * @param found a callback function to be called on success, failure or timeout (only if
ICTFBI 0:4edb816d21e1 930 * ERR_INPROGRESS is returned!)
ICTFBI 0:4edb816d21e1 931 * @param callback_arg argument to pass to the callback function
ICTFBI 0:4edb816d21e1 932 * @return a err_t return code.
ICTFBI 0:4edb816d21e1 933 */
ICTFBI 0:4edb816d21e1 934 err_t
ICTFBI 0:4edb816d21e1 935 dns_gethostbyname(const char *hostname, ip_addr_t *addr, dns_found_callback found,
ICTFBI 0:4edb816d21e1 936 void *callback_arg)
ICTFBI 0:4edb816d21e1 937 {
ICTFBI 0:4edb816d21e1 938 u32_t ipaddr;
ICTFBI 0:4edb816d21e1 939 /* not initialized or no valid server yet, or invalid addr pointer
ICTFBI 0:4edb816d21e1 940 * or invalid hostname or invalid hostname length */
ICTFBI 0:4edb816d21e1 941 if ((dns_pcb == NULL) || (addr == NULL) ||
ICTFBI 0:4edb816d21e1 942 (!hostname) || (!hostname[0]) ||
ICTFBI 0:4edb816d21e1 943 (strlen(hostname) >= DNS_MAX_NAME_LENGTH)) {
ICTFBI 0:4edb816d21e1 944 return ERR_VAL;
ICTFBI 0:4edb816d21e1 945 }
ICTFBI 0:4edb816d21e1 946
ICTFBI 0:4edb816d21e1 947 #if LWIP_HAVE_LOOPIF
ICTFBI 0:4edb816d21e1 948 if (strcmp(hostname, "localhost")==0) {
ICTFBI 0:4edb816d21e1 949 ip_addr_set_loopback(addr);
ICTFBI 0:4edb816d21e1 950 return ERR_OK;
ICTFBI 0:4edb816d21e1 951 }
ICTFBI 0:4edb816d21e1 952 #endif /* LWIP_HAVE_LOOPIF */
ICTFBI 0:4edb816d21e1 953
ICTFBI 0:4edb816d21e1 954 /* host name already in octet notation? set ip addr and return ERR_OK */
ICTFBI 0:4edb816d21e1 955 ipaddr = ipaddr_addr(hostname);
ICTFBI 0:4edb816d21e1 956 if (ipaddr == IPADDR_NONE) {
ICTFBI 0:4edb816d21e1 957 /* already have this address cached? */
ICTFBI 0:4edb816d21e1 958 ipaddr = dns_lookup(hostname);
ICTFBI 0:4edb816d21e1 959 }
ICTFBI 0:4edb816d21e1 960 if (ipaddr != IPADDR_NONE) {
ICTFBI 0:4edb816d21e1 961 ip4_addr_set_u32(addr, ipaddr);
ICTFBI 0:4edb816d21e1 962 return ERR_OK;
ICTFBI 0:4edb816d21e1 963 }
ICTFBI 0:4edb816d21e1 964
ICTFBI 0:4edb816d21e1 965 /* queue query with specified callback */
ICTFBI 0:4edb816d21e1 966 return dns_enqueue(hostname, found, callback_arg);
ICTFBI 0:4edb816d21e1 967 }
ICTFBI 0:4edb816d21e1 968
ICTFBI 0:4edb816d21e1 969 #endif /* LWIP_DNS */