Pascal Nysten / lwip

Important changes to repositories hosted on mbed.com

Mbed hosted mercurial repositories are deprecated and are due to be permanently deleted in July 2026.

To keep a copy of this software download the repository Zip archive or clone locally using Mercurial.

It is also possible to export all your personal repositories from the account settings page.

Dependencies:   DebugLib

Dependents:   LoRaWAN-lmic-app LoRaWAN-lmic-app LoRaWAN-test-10secs LoRaPersonalizedDeviceForEverynet ... more

Fork of lwip_ppp_ethernet by Donatien Garnier

src/core/dns.c@3:a9e6ba815945, 2015-11-20 (annotated)

Committer:
pnysten
Date:
Fri Nov 20 12:30:58 2015 +0000
Revision:
3:a9e6ba815945
Parent:
0:8e01dca41002 
Adapted to Nucleo, LoRa Semtech

Who changed what in which revision?

UserRevisionLine numberNew contents of line
donatien 0:8e01dca41002 1 /**
donatien 0:8e01dca41002 2 * @file
donatien 0:8e01dca41002 3 * DNS - host name to IP address resolver.
donatien 0:8e01dca41002 4 *
donatien 0:8e01dca41002 5 */
donatien 0:8e01dca41002 6
donatien 0:8e01dca41002 7 /**
donatien 0:8e01dca41002 8
donatien 0:8e01dca41002 9 * This file implements a DNS host name to IP address resolver.
donatien 0:8e01dca41002 10
donatien 0:8e01dca41002 11 * Port to lwIP from uIP
donatien 0:8e01dca41002 12 * by Jim Pettinato April 2007
donatien 0:8e01dca41002 13
donatien 0:8e01dca41002 14 * uIP version Copyright (c) 2002-2003, Adam Dunkels.
donatien 0:8e01dca41002 15 * All rights reserved.
donatien 0:8e01dca41002 16 *
donatien 0:8e01dca41002 17 * Redistribution and use in source and binary forms, with or without
donatien 0:8e01dca41002 18 * modification, are permitted provided that the following conditions
donatien 0:8e01dca41002 19 * are met:
donatien 0:8e01dca41002 20 * 1. Redistributions of source code must retain the above copyright
donatien 0:8e01dca41002 21 * notice, this list of conditions and the following disclaimer.
donatien 0:8e01dca41002 22 * 2. Redistributions in binary form must reproduce the above copyright
donatien 0:8e01dca41002 23 * notice, this list of conditions and the following disclaimer in the
donatien 0:8e01dca41002 24 * documentation and/or other materials provided with the distribution.
donatien 0:8e01dca41002 25 * 3. The name of the author may not be used to endorse or promote
donatien 0:8e01dca41002 26 * products derived from this software without specific prior
donatien 0:8e01dca41002 27 * written permission.
donatien 0:8e01dca41002 28 *
donatien 0:8e01dca41002 29 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
donatien 0:8e01dca41002 30 * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
donatien 0:8e01dca41002 31 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
donatien 0:8e01dca41002 32 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
donatien 0:8e01dca41002 33 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
donatien 0:8e01dca41002 34 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
donatien 0:8e01dca41002 35 * GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
donatien 0:8e01dca41002 36 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
donatien 0:8e01dca41002 37 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
donatien 0:8e01dca41002 38 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
donatien 0:8e01dca41002 39 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
donatien 0:8e01dca41002 40 *
donatien 0:8e01dca41002 41 *
donatien 0:8e01dca41002 42 * DNS.C
donatien 0:8e01dca41002 43 *
donatien 0:8e01dca41002 44 * The lwIP DNS resolver functions are used to lookup a host name and
donatien 0:8e01dca41002 45 * map it to a numerical IP address. It maintains a list of resolved
donatien 0:8e01dca41002 46 * hostnames that can be queried with the dns_lookup() function.
donatien 0:8e01dca41002 47 * New hostnames can be resolved using the dns_query() function.
donatien 0:8e01dca41002 48 *
donatien 0:8e01dca41002 49 * The lwIP version of the resolver also adds a non-blocking version of
donatien 0:8e01dca41002 50 * gethostbyname() that will work with a raw API application. This function
donatien 0:8e01dca41002 51 * checks for an IP address string first and converts it if it is valid.
donatien 0:8e01dca41002 52 * gethostbyname() then does a dns_lookup() to see if the name is
donatien 0:8e01dca41002 53 * already in the table. If so, the IP is returned. If not, a query is
donatien 0:8e01dca41002 54 * issued and the function returns with a ERR_INPROGRESS status. The app
donatien 0:8e01dca41002 55 * using the dns client must then go into a waiting state.
donatien 0:8e01dca41002 56 *
donatien 0:8e01dca41002 57 * Once a hostname has been resolved (or found to be non-existent),
donatien 0:8e01dca41002 58 * the resolver code calls a specified callback function (which
donatien 0:8e01dca41002 59 * must be implemented by the module that uses the resolver).
donatien 0:8e01dca41002 60 */
donatien 0:8e01dca41002 61
donatien 0:8e01dca41002 62 /*-----------------------------------------------------------------------------
donatien 0:8e01dca41002 63 * RFC 1035 - Domain names - implementation and specification
donatien 0:8e01dca41002 64 * RFC 2181 - Clarifications to the DNS Specification
donatien 0:8e01dca41002 65 *----------------------------------------------------------------------------*/
donatien 0:8e01dca41002 66
donatien 0:8e01dca41002 67 /** @todo: define good default values (rfc compliance) */
donatien 0:8e01dca41002 68 /** @todo: improve answer parsing, more checkings... */
donatien 0:8e01dca41002 69 /** @todo: check RFC1035 - 7.3. Processing responses */
donatien 0:8e01dca41002 70
donatien 0:8e01dca41002 71 /*-----------------------------------------------------------------------------
donatien 0:8e01dca41002 72 * Includes
donatien 0:8e01dca41002 73 *----------------------------------------------------------------------------*/
donatien 0:8e01dca41002 74
donatien 0:8e01dca41002 75 #include "lwip/opt.h"
donatien 0:8e01dca41002 76
donatien 0:8e01dca41002 77 #if LWIP_DNS /* don't build if not configured for use in lwipopts.h */
donatien 0:8e01dca41002 78
donatien 0:8e01dca41002 79 #include "lwip/udp.h"
donatien 0:8e01dca41002 80 #include "lwip/mem.h"
donatien 0:8e01dca41002 81 #include "lwip/memp.h"
donatien 0:8e01dca41002 82 #include "lwip/dns.h"
donatien 0:8e01dca41002 83
donatien 0:8e01dca41002 84 #include <string.h>
donatien 0:8e01dca41002 85
donatien 0:8e01dca41002 86 /** DNS server IP address */
donatien 0:8e01dca41002 87 #ifndef DNS_SERVER_ADDRESS
donatien 0:8e01dca41002 88 #define DNS_SERVER_ADDRESS(ipaddr) (ip4_addr_set_u32(ipaddr, ipaddr_addr("208.67.222.222"))) /* resolver1.opendns.com */
donatien 0:8e01dca41002 89 #endif
donatien 0:8e01dca41002 90
donatien 0:8e01dca41002 91 /** DNS server port address */
donatien 0:8e01dca41002 92 #ifndef DNS_SERVER_PORT
donatien 0:8e01dca41002 93 #define DNS_SERVER_PORT 53
donatien 0:8e01dca41002 94 #endif
donatien 0:8e01dca41002 95
donatien 0:8e01dca41002 96 /** DNS maximum number of retries when asking for a name, before "timeout". */
donatien 0:8e01dca41002 97 #ifndef DNS_MAX_RETRIES
donatien 0:8e01dca41002 98 #define DNS_MAX_RETRIES 4
donatien 0:8e01dca41002 99 #endif
donatien 0:8e01dca41002 100
donatien 0:8e01dca41002 101 /** DNS resource record max. TTL (one week as default) */
donatien 0:8e01dca41002 102 #ifndef DNS_MAX_TTL
donatien 0:8e01dca41002 103 #define DNS_MAX_TTL 604800
donatien 0:8e01dca41002 104 #endif
donatien 0:8e01dca41002 105
donatien 0:8e01dca41002 106 /* DNS protocol flags */
donatien 0:8e01dca41002 107 #define DNS_FLAG1_RESPONSE 0x80
donatien 0:8e01dca41002 108 #define DNS_FLAG1_OPCODE_STATUS 0x10
donatien 0:8e01dca41002 109 #define DNS_FLAG1_OPCODE_INVERSE 0x08
donatien 0:8e01dca41002 110 #define DNS_FLAG1_OPCODE_STANDARD 0x00
donatien 0:8e01dca41002 111 #define DNS_FLAG1_AUTHORATIVE 0x04
donatien 0:8e01dca41002 112 #define DNS_FLAG1_TRUNC 0x02
donatien 0:8e01dca41002 113 #define DNS_FLAG1_RD 0x01
donatien 0:8e01dca41002 114 #define DNS_FLAG2_RA 0x80
donatien 0:8e01dca41002 115 #define DNS_FLAG2_ERR_MASK 0x0f
donatien 0:8e01dca41002 116 #define DNS_FLAG2_ERR_NONE 0x00
donatien 0:8e01dca41002 117 #define DNS_FLAG2_ERR_NAME 0x03
donatien 0:8e01dca41002 118
donatien 0:8e01dca41002 119 /* DNS protocol states */
donatien 0:8e01dca41002 120 #define DNS_STATE_UNUSED 0
donatien 0:8e01dca41002 121 #define DNS_STATE_NEW 1
donatien 0:8e01dca41002 122 #define DNS_STATE_ASKING 2
donatien 0:8e01dca41002 123 #define DNS_STATE_DONE 3
donatien 0:8e01dca41002 124
donatien 0:8e01dca41002 125 #ifdef PACK_STRUCT_USE_INCLUDES
donatien 0:8e01dca41002 126 # include "arch/bpstruct.h"
donatien 0:8e01dca41002 127 #endif
donatien 0:8e01dca41002 128 PACK_STRUCT_BEGIN
donatien 0:8e01dca41002 129 /** DNS message header */
donatien 0:8e01dca41002 130 struct dns_hdr {
donatien 0:8e01dca41002 131 PACK_STRUCT_FIELD(u16_t id);
donatien 0:8e01dca41002 132 PACK_STRUCT_FIELD(u8_t flags1);
donatien 0:8e01dca41002 133 PACK_STRUCT_FIELD(u8_t flags2);
donatien 0:8e01dca41002 134 PACK_STRUCT_FIELD(u16_t numquestions);
donatien 0:8e01dca41002 135 PACK_STRUCT_FIELD(u16_t numanswers);
donatien 0:8e01dca41002 136 PACK_STRUCT_FIELD(u16_t numauthrr);
donatien 0:8e01dca41002 137 PACK_STRUCT_FIELD(u16_t numextrarr);
donatien 0:8e01dca41002 138 } PACK_STRUCT_STRUCT;
donatien 0:8e01dca41002 139 PACK_STRUCT_END
donatien 0:8e01dca41002 140 #ifdef PACK_STRUCT_USE_INCLUDES
donatien 0:8e01dca41002 141 # include "arch/epstruct.h"
donatien 0:8e01dca41002 142 #endif
donatien 0:8e01dca41002 143 #define SIZEOF_DNS_HDR 12
donatien 0:8e01dca41002 144
donatien 0:8e01dca41002 145 /** DNS query message structure.
donatien 0:8e01dca41002 146 No packing needed: only used locally on the stack. */
donatien 0:8e01dca41002 147 struct dns_query {
donatien 0:8e01dca41002 148 /* DNS query record starts with either a domain name or a pointer
donatien 0:8e01dca41002 149 to a name already present somewhere in the packet. */
donatien 0:8e01dca41002 150 u16_t type;
donatien 0:8e01dca41002 151 u16_t cls;
donatien 0:8e01dca41002 152 };
donatien 0:8e01dca41002 153 #define SIZEOF_DNS_QUERY 4
donatien 0:8e01dca41002 154
donatien 0:8e01dca41002 155 /** DNS answer message structure.
donatien 0:8e01dca41002 156 No packing needed: only used locally on the stack. */
donatien 0:8e01dca41002 157 struct dns_answer {
donatien 0:8e01dca41002 158 /* DNS answer record starts with either a domain name or a pointer
donatien 0:8e01dca41002 159 to a name already present somewhere in the packet. */
donatien 0:8e01dca41002 160 u16_t type;
donatien 0:8e01dca41002 161 u16_t cls;
donatien 0:8e01dca41002 162 u32_t ttl;
donatien 0:8e01dca41002 163 u16_t len;
donatien 0:8e01dca41002 164 };
donatien 0:8e01dca41002 165 #define SIZEOF_DNS_ANSWER 10
donatien 0:8e01dca41002 166
donatien 0:8e01dca41002 167 /** DNS table entry */
donatien 0:8e01dca41002 168 struct dns_table_entry {
donatien 0:8e01dca41002 169 u8_t state;
donatien 0:8e01dca41002 170 u8_t numdns;
donatien 0:8e01dca41002 171 u8_t tmr;
donatien 0:8e01dca41002 172 u8_t retries;
donatien 0:8e01dca41002 173 u8_t seqno;
donatien 0:8e01dca41002 174 u8_t err;
donatien 0:8e01dca41002 175 u32_t ttl;
donatien 0:8e01dca41002 176 char name[DNS_MAX_NAME_LENGTH];
donatien 0:8e01dca41002 177 ip_addr_t ipaddr;
donatien 0:8e01dca41002 178 /* pointer to callback on DNS query done */
donatien 0:8e01dca41002 179 dns_found_callback found;
donatien 0:8e01dca41002 180 void *arg;
donatien 0:8e01dca41002 181 };
donatien 0:8e01dca41002 182
donatien 0:8e01dca41002 183 #if DNS_LOCAL_HOSTLIST
donatien 0:8e01dca41002 184
donatien 0:8e01dca41002 185 #if DNS_LOCAL_HOSTLIST_IS_DYNAMIC
donatien 0:8e01dca41002 186 /** Local host-list. For hostnames in this list, no
donatien 0:8e01dca41002 187 * external name resolution is performed */
donatien 0:8e01dca41002 188 static struct local_hostlist_entry *local_hostlist_dynamic;
donatien 0:8e01dca41002 189 #else /* DNS_LOCAL_HOSTLIST_IS_DYNAMIC */
donatien 0:8e01dca41002 190
donatien 0:8e01dca41002 191 /** Defining this allows the local_hostlist_static to be placed in a different
donatien 0:8e01dca41002 192 * linker section (e.g. FLASH) */
donatien 0:8e01dca41002 193 #ifndef DNS_LOCAL_HOSTLIST_STORAGE_PRE
donatien 0:8e01dca41002 194 #define DNS_LOCAL_HOSTLIST_STORAGE_PRE static
donatien 0:8e01dca41002 195 #endif /* DNS_LOCAL_HOSTLIST_STORAGE_PRE */
donatien 0:8e01dca41002 196 /** Defining this allows the local_hostlist_static to be placed in a different
donatien 0:8e01dca41002 197 * linker section (e.g. FLASH) */
donatien 0:8e01dca41002 198 #ifndef DNS_LOCAL_HOSTLIST_STORAGE_POST
donatien 0:8e01dca41002 199 #define DNS_LOCAL_HOSTLIST_STORAGE_POST
donatien 0:8e01dca41002 200 #endif /* DNS_LOCAL_HOSTLIST_STORAGE_POST */
donatien 0:8e01dca41002 201 DNS_LOCAL_HOSTLIST_STORAGE_PRE struct local_hostlist_entry local_hostlist_static[]
donatien 0:8e01dca41002 202 DNS_LOCAL_HOSTLIST_STORAGE_POST = DNS_LOCAL_HOSTLIST_INIT;
donatien 0:8e01dca41002 203
donatien 0:8e01dca41002 204 #endif /* DNS_LOCAL_HOSTLIST_IS_DYNAMIC */
donatien 0:8e01dca41002 205
donatien 0:8e01dca41002 206 static void dns_init_local();
donatien 0:8e01dca41002 207 #endif /* DNS_LOCAL_HOSTLIST */
donatien 0:8e01dca41002 208
donatien 0:8e01dca41002 209
donatien 0:8e01dca41002 210 /* forward declarations */
donatien 0:8e01dca41002 211 static void dns_recv(void *s, struct udp_pcb *pcb, struct pbuf *p, ip_addr_t *addr, u16_t port);
donatien 0:8e01dca41002 212 static void dns_check_entries(void);
donatien 0:8e01dca41002 213
donatien 0:8e01dca41002 214 /*-----------------------------------------------------------------------------
donatien 0:8e01dca41002 215 * Globales
donatien 0:8e01dca41002 216 *----------------------------------------------------------------------------*/
donatien 0:8e01dca41002 217
donatien 0:8e01dca41002 218 /* DNS variables */
donatien 0:8e01dca41002 219 static struct udp_pcb *dns_pcb;
donatien 0:8e01dca41002 220 static u8_t dns_seqno;
donatien 0:8e01dca41002 221 static struct dns_table_entry dns_table[DNS_TABLE_SIZE];
donatien 0:8e01dca41002 222 static ip_addr_t dns_servers[DNS_MAX_SERVERS];
donatien 0:8e01dca41002 223 /** Contiguous buffer for processing responses */
donatien 0:8e01dca41002 224 static u8_t dns_payload_buffer[LWIP_MEM_ALIGN_BUFFER(DNS_MSG_SIZE)];
donatien 0:8e01dca41002 225 static u8_t* dns_payload;
donatien 0:8e01dca41002 226
donatien 0:8e01dca41002 227 /**
donatien 0:8e01dca41002 228 * Initialize the resolver: set up the UDP pcb and configure the default server
donatien 0:8e01dca41002 229 * (DNS_SERVER_ADDRESS).
donatien 0:8e01dca41002 230 */
donatien 0:8e01dca41002 231 void
donatien 0:8e01dca41002 232 dns_init()
donatien 0:8e01dca41002 233 {
donatien 0:8e01dca41002 234 ip_addr_t dnsserver;
donatien 0:8e01dca41002 235
donatien 0:8e01dca41002 236 dns_payload = (u8_t *)LWIP_MEM_ALIGN(dns_payload_buffer);
donatien 0:8e01dca41002 237
donatien 0:8e01dca41002 238 /* initialize default DNS server address */
donatien 0:8e01dca41002 239 DNS_SERVER_ADDRESS(&dnsserver);
donatien 0:8e01dca41002 240
donatien 0:8e01dca41002 241 LWIP_DEBUGF(DNS_DEBUG, ("dns_init: initializing\n"));
donatien 0:8e01dca41002 242
donatien 0:8e01dca41002 243 /* if dns client not yet initialized... */
donatien 0:8e01dca41002 244 if (dns_pcb == NULL) {
donatien 0:8e01dca41002 245 dns_pcb = udp_new();
donatien 0:8e01dca41002 246
donatien 0:8e01dca41002 247 if (dns_pcb != NULL) {
donatien 0:8e01dca41002 248 /* initialize DNS table not needed (initialized to zero since it is a
donatien 0:8e01dca41002 249 * global variable) */
donatien 0:8e01dca41002 250 LWIP_ASSERT("For implicit initialization to work, DNS_STATE_UNUSED needs to be 0",
donatien 0:8e01dca41002 251 DNS_STATE_UNUSED == 0);
donatien 0:8e01dca41002 252
donatien 0:8e01dca41002 253 /* initialize DNS client */
donatien 0:8e01dca41002 254 udp_bind(dns_pcb, IP_ADDR_ANY, 0);
donatien 0:8e01dca41002 255 udp_recv(dns_pcb, dns_recv, NULL);
donatien 0:8e01dca41002 256
donatien 0:8e01dca41002 257 /* initialize default DNS primary server */
donatien 0:8e01dca41002 258 dns_setserver(0, &dnsserver);
donatien 0:8e01dca41002 259 }
donatien 0:8e01dca41002 260 }
donatien 0:8e01dca41002 261 #if DNS_LOCAL_HOSTLIST
donatien 0:8e01dca41002 262 dns_init_local();
donatien 0:8e01dca41002 263 #endif
donatien 0:8e01dca41002 264 }
donatien 0:8e01dca41002 265
donatien 0:8e01dca41002 266 /**
donatien 0:8e01dca41002 267 * Initialize one of the DNS servers.
donatien 0:8e01dca41002 268 *
donatien 0:8e01dca41002 269 * @param numdns the index of the DNS server to set must be < DNS_MAX_SERVERS
donatien 0:8e01dca41002 270 * @param dnsserver IP address of the DNS server to set
donatien 0:8e01dca41002 271 */
donatien 0:8e01dca41002 272 void
donatien 0:8e01dca41002 273 dns_setserver(u8_t numdns, ip_addr_t *dnsserver)
donatien 0:8e01dca41002 274 {
donatien 0:8e01dca41002 275 if ((numdns < DNS_MAX_SERVERS) && (dns_pcb != NULL) &&
donatien 0:8e01dca41002 276 (dnsserver != NULL) && !ip_addr_isany(dnsserver)) {
donatien 0:8e01dca41002 277 dns_servers[numdns] = (*dnsserver);
donatien 0:8e01dca41002 278 }
donatien 0:8e01dca41002 279 }
donatien 0:8e01dca41002 280
donatien 0:8e01dca41002 281 /**
donatien 0:8e01dca41002 282 * Obtain one of the currently configured DNS server.
donatien 0:8e01dca41002 283 *
donatien 0:8e01dca41002 284 * @param numdns the index of the DNS server
donatien 0:8e01dca41002 285 * @return IP address of the indexed DNS server or "ip_addr_any" if the DNS
donatien 0:8e01dca41002 286 * server has not been configured.
donatien 0:8e01dca41002 287 */
donatien 0:8e01dca41002 288 ip_addr_t
donatien 0:8e01dca41002 289 dns_getserver(u8_t numdns)
donatien 0:8e01dca41002 290 {
donatien 0:8e01dca41002 291 if (numdns < DNS_MAX_SERVERS) {
donatien 0:8e01dca41002 292 return dns_servers[numdns];
donatien 0:8e01dca41002 293 } else {
donatien 0:8e01dca41002 294 return *IP_ADDR_ANY;
donatien 0:8e01dca41002 295 }
donatien 0:8e01dca41002 296 }
donatien 0:8e01dca41002 297
donatien 0:8e01dca41002 298 /**
donatien 0:8e01dca41002 299 * The DNS resolver client timer - handle retries and timeouts and should
donatien 0:8e01dca41002 300 * be called every DNS_TMR_INTERVAL milliseconds (every second by default).
donatien 0:8e01dca41002 301 */
donatien 0:8e01dca41002 302 void
donatien 0:8e01dca41002 303 dns_tmr(void)
donatien 0:8e01dca41002 304 {
donatien 0:8e01dca41002 305 if (dns_pcb != NULL) {
donatien 0:8e01dca41002 306 LWIP_DEBUGF(DNS_DEBUG, ("dns_tmr: dns_check_entries\n"));
donatien 0:8e01dca41002 307 dns_check_entries();
donatien 0:8e01dca41002 308 }
donatien 0:8e01dca41002 309 }
donatien 0:8e01dca41002 310
donatien 0:8e01dca41002 311 #if DNS_LOCAL_HOSTLIST
donatien 0:8e01dca41002 312 static void
donatien 0:8e01dca41002 313 dns_init_local()
donatien 0:8e01dca41002 314 {
donatien 0:8e01dca41002 315 #if DNS_LOCAL_HOSTLIST_IS_DYNAMIC && defined(DNS_LOCAL_HOSTLIST_INIT)
donatien 0:8e01dca41002 316 int i;
donatien 0:8e01dca41002 317 struct local_hostlist_entry *entry;
donatien 0:8e01dca41002 318 /* Dynamic: copy entries from DNS_LOCAL_HOSTLIST_INIT to list */
donatien 0:8e01dca41002 319 struct local_hostlist_entry local_hostlist_init[] = DNS_LOCAL_HOSTLIST_INIT;
donatien 0:8e01dca41002 320 size_t namelen;
donatien 0:8e01dca41002 321 for (i = 0; i < sizeof(local_hostlist_init) / sizeof(struct local_hostlist_entry); i++) {
donatien 0:8e01dca41002 322 struct local_hostlist_entry *init_entry = &local_hostlist_init[i];
donatien 0:8e01dca41002 323 LWIP_ASSERT("invalid host name (NULL)", init_entry->name != NULL);
donatien 0:8e01dca41002 324 namelen = strlen(init_entry->name);
donatien 0:8e01dca41002 325 LWIP_ASSERT("namelen <= DNS_LOCAL_HOSTLIST_MAX_NAMELEN", namelen <= DNS_LOCAL_HOSTLIST_MAX_NAMELEN);
donatien 0:8e01dca41002 326 entry = (struct local_hostlist_entry *)memp_malloc(MEMP_LOCALHOSTLIST);
donatien 0:8e01dca41002 327 LWIP_ASSERT("mem-error in dns_init_local", entry != NULL);
donatien 0:8e01dca41002 328 if (entry != NULL) {
donatien 0:8e01dca41002 329 entry->name = (char*)entry + sizeof(struct local_hostlist_entry);
donatien 0:8e01dca41002 330 MEMCPY((char*)entry->name, init_entry->name, namelen);
donatien 0:8e01dca41002 331 ((char*)entry->name)[namelen] = 0;
donatien 0:8e01dca41002 332 entry->addr = init_entry->addr;
donatien 0:8e01dca41002 333 entry->next = local_hostlist_dynamic;
donatien 0:8e01dca41002 334 local_hostlist_dynamic = entry;
donatien 0:8e01dca41002 335 }
donatien 0:8e01dca41002 336 }
donatien 0:8e01dca41002 337 #endif /* DNS_LOCAL_HOSTLIST_IS_DYNAMIC && defined(DNS_LOCAL_HOSTLIST_INIT) */
donatien 0:8e01dca41002 338 }
donatien 0:8e01dca41002 339
donatien 0:8e01dca41002 340 /**
donatien 0:8e01dca41002 341 * Scans the local host-list for a hostname.
donatien 0:8e01dca41002 342 *
donatien 0:8e01dca41002 343 * @param hostname Hostname to look for in the local host-list
donatien 0:8e01dca41002 344 * @return The first IP address for the hostname in the local host-list or
donatien 0:8e01dca41002 345 * IPADDR_NONE if not found.
donatien 0:8e01dca41002 346 */
donatien 0:8e01dca41002 347 static u32_t
donatien 0:8e01dca41002 348 dns_lookup_local(const char *hostname)
donatien 0:8e01dca41002 349 {
donatien 0:8e01dca41002 350 #if DNS_LOCAL_HOSTLIST_IS_DYNAMIC
donatien 0:8e01dca41002 351 struct local_hostlist_entry *entry = local_hostlist_dynamic;
donatien 0:8e01dca41002 352 while(entry != NULL) {
donatien 0:8e01dca41002 353 if(strcmp(entry->name, hostname) == 0) {
donatien 0:8e01dca41002 354 return ip4_addr_get_u32(&entry->addr);
donatien 0:8e01dca41002 355 }
donatien 0:8e01dca41002 356 entry = entry->next;
donatien 0:8e01dca41002 357 }
donatien 0:8e01dca41002 358 #else /* DNS_LOCAL_HOSTLIST_IS_DYNAMIC */
donatien 0:8e01dca41002 359 int i;
donatien 0:8e01dca41002 360 for (i = 0; i < sizeof(local_hostlist_static) / sizeof(struct local_hostlist_entry); i++) {
donatien 0:8e01dca41002 361 if(strcmp(local_hostlist_static[i].name, hostname) == 0) {
donatien 0:8e01dca41002 362 return ip4_addr_get_u32(&local_hostlist_static[i].addr);
donatien 0:8e01dca41002 363 }
donatien 0:8e01dca41002 364 }
donatien 0:8e01dca41002 365 #endif /* DNS_LOCAL_HOSTLIST_IS_DYNAMIC */
donatien 0:8e01dca41002 366 return IPADDR_NONE;
donatien 0:8e01dca41002 367 }
donatien 0:8e01dca41002 368
donatien 0:8e01dca41002 369 #if DNS_LOCAL_HOSTLIST_IS_DYNAMIC
donatien 0:8e01dca41002 370 /** Remove all entries from the local host-list for a specific hostname
donatien 0:8e01dca41002 371 * and/or IP addess
donatien 0:8e01dca41002 372 *
donatien 0:8e01dca41002 373 * @param hostname hostname for which entries shall be removed from the local
donatien 0:8e01dca41002 374 * host-list
donatien 0:8e01dca41002 375 * @param addr address for which entries shall be removed from the local host-list
donatien 0:8e01dca41002 376 * @return the number of removed entries
donatien 0:8e01dca41002 377 */
donatien 0:8e01dca41002 378 int
donatien 0:8e01dca41002 379 dns_local_removehost(const char *hostname, const ip_addr_t *addr)
donatien 0:8e01dca41002 380 {
donatien 0:8e01dca41002 381 int removed = 0;
donatien 0:8e01dca41002 382 struct local_hostlist_entry *entry = local_hostlist_dynamic;
donatien 0:8e01dca41002 383 struct local_hostlist_entry *last_entry = NULL;
donatien 0:8e01dca41002 384 while (entry != NULL) {
donatien 0:8e01dca41002 385 if (((hostname == NULL) || !strcmp(entry->name, hostname)) &&
donatien 0:8e01dca41002 386 ((addr == NULL) || ip_addr_cmp(&entry->addr, addr))) {
donatien 0:8e01dca41002 387 struct local_hostlist_entry *free_entry;
donatien 0:8e01dca41002 388 if (last_entry != NULL) {
donatien 0:8e01dca41002 389 last_entry->next = entry->next;
donatien 0:8e01dca41002 390 } else {
donatien 0:8e01dca41002 391 local_hostlist_dynamic = entry->next;
donatien 0:8e01dca41002 392 }
donatien 0:8e01dca41002 393 free_entry = entry;
donatien 0:8e01dca41002 394 entry = entry->next;
donatien 0:8e01dca41002 395 memp_free(MEMP_LOCALHOSTLIST, free_entry);
donatien 0:8e01dca41002 396 removed++;
donatien 0:8e01dca41002 397 } else {
donatien 0:8e01dca41002 398 last_entry = entry;
donatien 0:8e01dca41002 399 entry = entry->next;
donatien 0:8e01dca41002 400 }
donatien 0:8e01dca41002 401 }
donatien 0:8e01dca41002 402 return removed;
donatien 0:8e01dca41002 403 }
donatien 0:8e01dca41002 404
donatien 0:8e01dca41002 405 /**
donatien 0:8e01dca41002 406 * Add a hostname/IP address pair to the local host-list.
donatien 0:8e01dca41002 407 * Duplicates are not checked.
donatien 0:8e01dca41002 408 *
donatien 0:8e01dca41002 409 * @param hostname hostname of the new entry
donatien 0:8e01dca41002 410 * @param addr IP address of the new entry
donatien 0:8e01dca41002 411 * @return ERR_OK if succeeded or ERR_MEM on memory error
donatien 0:8e01dca41002 412 */
donatien 0:8e01dca41002 413 err_t
donatien 0:8e01dca41002 414 dns_local_addhost(const char *hostname, const ip_addr_t *addr)
donatien 0:8e01dca41002 415 {
donatien 0:8e01dca41002 416 struct local_hostlist_entry *entry;
donatien 0:8e01dca41002 417 size_t namelen;
donatien 0:8e01dca41002 418 LWIP_ASSERT("invalid host name (NULL)", hostname != NULL);
donatien 0:8e01dca41002 419 namelen = strlen(hostname);
donatien 0:8e01dca41002 420 LWIP_ASSERT("namelen <= DNS_LOCAL_HOSTLIST_MAX_NAMELEN", namelen <= DNS_LOCAL_HOSTLIST_MAX_NAMELEN);
donatien 0:8e01dca41002 421 entry = (struct local_hostlist_entry *)memp_malloc(MEMP_LOCALHOSTLIST);
donatien 0:8e01dca41002 422 if (entry == NULL) {
donatien 0:8e01dca41002 423 return ERR_MEM;
donatien 0:8e01dca41002 424 }
donatien 0:8e01dca41002 425 entry->name = (char*)entry + sizeof(struct local_hostlist_entry);
donatien 0:8e01dca41002 426 MEMCPY((char*)entry->name, hostname, namelen);
donatien 0:8e01dca41002 427 ((char*)entry->name)[namelen] = 0;
donatien 0:8e01dca41002 428 ip_addr_copy(entry->addr, *addr);
donatien 0:8e01dca41002 429 entry->next = local_hostlist_dynamic;
donatien 0:8e01dca41002 430 local_hostlist_dynamic = entry;
donatien 0:8e01dca41002 431 return ERR_OK;
donatien 0:8e01dca41002 432 }
donatien 0:8e01dca41002 433 #endif /* DNS_LOCAL_HOSTLIST_IS_DYNAMIC*/
donatien 0:8e01dca41002 434 #endif /* DNS_LOCAL_HOSTLIST */
donatien 0:8e01dca41002 435
donatien 0:8e01dca41002 436 /**
donatien 0:8e01dca41002 437 * Look up a hostname in the array of known hostnames.
donatien 0:8e01dca41002 438 *
donatien 0:8e01dca41002 439 * @note This function only looks in the internal array of known
donatien 0:8e01dca41002 440 * hostnames, it does not send out a query for the hostname if none
donatien 0:8e01dca41002 441 * was found. The function dns_enqueue() can be used to send a query
donatien 0:8e01dca41002 442 * for a hostname.
donatien 0:8e01dca41002 443 *
donatien 0:8e01dca41002 444 * @param name the hostname to look up
donatien 0:8e01dca41002 445 * @return the hostname's IP address, as u32_t (instead of ip_addr_t to
donatien 0:8e01dca41002 446 * better check for failure: != IPADDR_NONE) or IPADDR_NONE if the hostname
donatien 0:8e01dca41002 447 * was not found in the cached dns_table.
donatien 0:8e01dca41002 448 */
donatien 0:8e01dca41002 449 static u32_t
donatien 0:8e01dca41002 450 dns_lookup(const char *name)
donatien 0:8e01dca41002 451 {
donatien 0:8e01dca41002 452 u8_t i;
donatien 0:8e01dca41002 453 #if DNS_LOCAL_HOSTLIST || defined(DNS_LOOKUP_LOCAL_EXTERN)
donatien 0:8e01dca41002 454 u32_t addr;
donatien 0:8e01dca41002 455 #endif /* DNS_LOCAL_HOSTLIST || defined(DNS_LOOKUP_LOCAL_EXTERN) */
donatien 0:8e01dca41002 456 #if DNS_LOCAL_HOSTLIST
donatien 0:8e01dca41002 457 if ((addr = dns_lookup_local(name)) != IPADDR_NONE) {
donatien 0:8e01dca41002 458 return addr;
donatien 0:8e01dca41002 459 }
donatien 0:8e01dca41002 460 #endif /* DNS_LOCAL_HOSTLIST */
donatien 0:8e01dca41002 461 #ifdef DNS_LOOKUP_LOCAL_EXTERN
donatien 0:8e01dca41002 462 if((addr = DNS_LOOKUP_LOCAL_EXTERN(name)) != IPADDR_NONE) {
donatien 0:8e01dca41002 463 return addr;
donatien 0:8e01dca41002 464 }
donatien 0:8e01dca41002 465 #endif /* DNS_LOOKUP_LOCAL_EXTERN */
donatien 0:8e01dca41002 466
donatien 0:8e01dca41002 467 /* Walk through name list, return entry if found. If not, return NULL. */
donatien 0:8e01dca41002 468 for (i = 0; i < DNS_TABLE_SIZE; ++i) {
donatien 0:8e01dca41002 469 if ((dns_table[i].state == DNS_STATE_DONE) &&
donatien 0:8e01dca41002 470 (strcmp(name, dns_table[i].name) == 0)) {
donatien 0:8e01dca41002 471 LWIP_DEBUGF(DNS_DEBUG, ("dns_lookup: \"%s\": found = ", name));
donatien 0:8e01dca41002 472 ip_addr_debug_print(DNS_DEBUG, &(dns_table[i].ipaddr));
donatien 0:8e01dca41002 473 LWIP_DEBUGF(DNS_DEBUG, ("\n"));
donatien 0:8e01dca41002 474 return ip4_addr_get_u32(&dns_table[i].ipaddr);
donatien 0:8e01dca41002 475 }
donatien 0:8e01dca41002 476 }
donatien 0:8e01dca41002 477
donatien 0:8e01dca41002 478 return IPADDR_NONE;
donatien 0:8e01dca41002 479 }
donatien 0:8e01dca41002 480
donatien 0:8e01dca41002 481 #if DNS_DOES_NAME_CHECK
donatien 0:8e01dca41002 482 /**
donatien 0:8e01dca41002 483 * Compare the "dotted" name "query" with the encoded name "response"
donatien 0:8e01dca41002 484 * to make sure an answer from the DNS server matches the current dns_table
donatien 0:8e01dca41002 485 * entry (otherwise, answers might arrive late for hostname not on the list
donatien 0:8e01dca41002 486 * any more).
donatien 0:8e01dca41002 487 *
donatien 0:8e01dca41002 488 * @param query hostname (not encoded) from the dns_table
donatien 0:8e01dca41002 489 * @param response encoded hostname in the DNS response
donatien 0:8e01dca41002 490 * @return 0: names equal; 1: names differ
donatien 0:8e01dca41002 491 */
donatien 0:8e01dca41002 492 static u8_t
donatien 0:8e01dca41002 493 dns_compare_name(unsigned char *query, unsigned char *response)
donatien 0:8e01dca41002 494 {
donatien 0:8e01dca41002 495 unsigned char n;
donatien 0:8e01dca41002 496
donatien 0:8e01dca41002 497 do {
donatien 0:8e01dca41002 498 n = *response++;
donatien 0:8e01dca41002 499 /** @see RFC 1035 - 4.1.4. Message compression */
donatien 0:8e01dca41002 500 if ((n & 0xc0) == 0xc0) {
donatien 0:8e01dca41002 501 /* Compressed name */
donatien 0:8e01dca41002 502 break;
donatien 0:8e01dca41002 503 } else {
donatien 0:8e01dca41002 504 /* Not compressed name */
donatien 0:8e01dca41002 505 while (n > 0) {
donatien 0:8e01dca41002 506 if ((*query) != (*response)) {
donatien 0:8e01dca41002 507 return 1;
donatien 0:8e01dca41002 508 }
donatien 0:8e01dca41002 509 ++response;
donatien 0:8e01dca41002 510 ++query;
donatien 0:8e01dca41002 511 --n;
donatien 0:8e01dca41002 512 };
donatien 0:8e01dca41002 513 ++query;
donatien 0:8e01dca41002 514 }
donatien 0:8e01dca41002 515 } while (*response != 0);
donatien 0:8e01dca41002 516
donatien 0:8e01dca41002 517 return 0;
donatien 0:8e01dca41002 518 }
donatien 0:8e01dca41002 519 #endif /* DNS_DOES_NAME_CHECK */
donatien 0:8e01dca41002 520
donatien 0:8e01dca41002 521 /**
donatien 0:8e01dca41002 522 * Walk through a compact encoded DNS name and return the end of the name.
donatien 0:8e01dca41002 523 *
donatien 0:8e01dca41002 524 * @param query encoded DNS name in the DNS server response
donatien 0:8e01dca41002 525 * @return end of the name
donatien 0:8e01dca41002 526 */
donatien 0:8e01dca41002 527 static unsigned char *
donatien 0:8e01dca41002 528 dns_parse_name(unsigned char *query)
donatien 0:8e01dca41002 529 {
donatien 0:8e01dca41002 530 unsigned char n;
donatien 0:8e01dca41002 531
donatien 0:8e01dca41002 532 do {
donatien 0:8e01dca41002 533 n = *query++;
donatien 0:8e01dca41002 534 /** @see RFC 1035 - 4.1.4. Message compression */
donatien 0:8e01dca41002 535 if ((n & 0xc0) == 0xc0) {
donatien 0:8e01dca41002 536 /* Compressed name */
donatien 0:8e01dca41002 537 break;
donatien 0:8e01dca41002 538 } else {
donatien 0:8e01dca41002 539 /* Not compressed name */
donatien 0:8e01dca41002 540 while (n > 0) {
donatien 0:8e01dca41002 541 ++query;
donatien 0:8e01dca41002 542 --n;
donatien 0:8e01dca41002 543 };
donatien 0:8e01dca41002 544 }
donatien 0:8e01dca41002 545 } while (*query != 0);
donatien 0:8e01dca41002 546
donatien 0:8e01dca41002 547 return query + 1;
donatien 0:8e01dca41002 548 }
donatien 0:8e01dca41002 549
donatien 0:8e01dca41002 550 /**
donatien 0:8e01dca41002 551 * Send a DNS query packet.
donatien 0:8e01dca41002 552 *
donatien 0:8e01dca41002 553 * @param numdns index of the DNS server in the dns_servers table
donatien 0:8e01dca41002 554 * @param name hostname to query
donatien 0:8e01dca41002 555 * @param id index of the hostname in dns_table, used as transaction ID in the
donatien 0:8e01dca41002 556 * DNS query packet
donatien 0:8e01dca41002 557 * @return ERR_OK if packet is sent; an err_t indicating the problem otherwise
donatien 0:8e01dca41002 558 */
donatien 0:8e01dca41002 559 static err_t
donatien 0:8e01dca41002 560 dns_send(u8_t numdns, const char* name, u8_t id)
donatien 0:8e01dca41002 561 {
donatien 0:8e01dca41002 562 err_t err;
donatien 0:8e01dca41002 563 struct dns_hdr *hdr;
donatien 0:8e01dca41002 564 struct dns_query qry;
donatien 0:8e01dca41002 565 struct pbuf *p;
donatien 0:8e01dca41002 566 char *query, *nptr;
donatien 0:8e01dca41002 567 const char *pHostname;
donatien 0:8e01dca41002 568 u8_t n;
donatien 0:8e01dca41002 569
donatien 0:8e01dca41002 570 LWIP_DEBUGF(DNS_DEBUG, ("dns_send: dns_servers[%"U16_F"] \"%s\": request\n",
donatien 0:8e01dca41002 571 (u16_t)(numdns), name));
donatien 0:8e01dca41002 572 LWIP_ASSERT("dns server out of array", numdns < DNS_MAX_SERVERS);
donatien 0:8e01dca41002 573 LWIP_ASSERT("dns server has no IP address set", !ip_addr_isany(&dns_servers[numdns]));
donatien 0:8e01dca41002 574
donatien 0:8e01dca41002 575 /* if here, we have either a new query or a retry on a previous query to process */
donatien 0:8e01dca41002 576 p = pbuf_alloc(PBUF_TRANSPORT, SIZEOF_DNS_HDR + DNS_MAX_NAME_LENGTH +
donatien 0:8e01dca41002 577 SIZEOF_DNS_QUERY, PBUF_RAM);
donatien 0:8e01dca41002 578 if (p != NULL) {
donatien 0:8e01dca41002 579 LWIP_ASSERT("pbuf must be in one piece", p->next == NULL);
donatien 0:8e01dca41002 580 /* fill dns header */
donatien 0:8e01dca41002 581 hdr = (struct dns_hdr*)p->payload;
donatien 0:8e01dca41002 582 memset(hdr, 0, SIZEOF_DNS_HDR);
donatien 0:8e01dca41002 583 hdr->id = htons(id);
donatien 0:8e01dca41002 584 hdr->flags1 = DNS_FLAG1_RD;
donatien 0:8e01dca41002 585 hdr->numquestions = PP_HTONS(1);
donatien 0:8e01dca41002 586 query = (char*)hdr + SIZEOF_DNS_HDR;
donatien 0:8e01dca41002 587 pHostname = name;
donatien 0:8e01dca41002 588 --pHostname;
donatien 0:8e01dca41002 589
donatien 0:8e01dca41002 590 /* convert hostname into suitable query format. */
donatien 0:8e01dca41002 591 do {
donatien 0:8e01dca41002 592 ++pHostname;
donatien 0:8e01dca41002 593 nptr = query;
donatien 0:8e01dca41002 594 ++query;
donatien 0:8e01dca41002 595 for(n = 0; *pHostname != '.' && *pHostname != 0; ++pHostname) {
donatien 0:8e01dca41002 596 *query = *pHostname;
donatien 0:8e01dca41002 597 ++query;
donatien 0:8e01dca41002 598 ++n;
donatien 0:8e01dca41002 599 }
donatien 0:8e01dca41002 600 *nptr = n;
donatien 0:8e01dca41002 601 } while(*pHostname != 0);
donatien 0:8e01dca41002 602 *query++='\0';
donatien 0:8e01dca41002 603
donatien 0:8e01dca41002 604 /* fill dns query */
donatien 0:8e01dca41002 605 qry.type = PP_HTONS(DNS_RRTYPE_A);
donatien 0:8e01dca41002 606 qry.cls = PP_HTONS(DNS_RRCLASS_IN);
donatien 0:8e01dca41002 607 SMEMCPY(query, &qry, SIZEOF_DNS_QUERY);
donatien 0:8e01dca41002 608
donatien 0:8e01dca41002 609 /* resize pbuf to the exact dns query */
donatien 0:8e01dca41002 610 pbuf_realloc(p, (u16_t)((query + SIZEOF_DNS_QUERY) - ((char*)(p->payload))));
donatien 0:8e01dca41002 611
donatien 0:8e01dca41002 612 /* connect to the server for faster receiving */
donatien 0:8e01dca41002 613 udp_connect(dns_pcb, &dns_servers[numdns], DNS_SERVER_PORT);
donatien 0:8e01dca41002 614 /* send dns packet */
donatien 0:8e01dca41002 615 err = udp_sendto(dns_pcb, p, &dns_servers[numdns], DNS_SERVER_PORT);
donatien 0:8e01dca41002 616
donatien 0:8e01dca41002 617 /* free pbuf */
donatien 0:8e01dca41002 618 pbuf_free(p);
donatien 0:8e01dca41002 619 } else {
donatien 0:8e01dca41002 620 err = ERR_MEM;
donatien 0:8e01dca41002 621 }
donatien 0:8e01dca41002 622
donatien 0:8e01dca41002 623 return err;
donatien 0:8e01dca41002 624 }
donatien 0:8e01dca41002 625
donatien 0:8e01dca41002 626 /**
donatien 0:8e01dca41002 627 * dns_check_entry() - see if pEntry has not yet been queried and, if so, sends out a query.
donatien 0:8e01dca41002 628 * Check an entry in the dns_table:
donatien 0:8e01dca41002 629 * - send out query for new entries
donatien 0:8e01dca41002 630 * - retry old pending entries on timeout (also with different servers)
donatien 0:8e01dca41002 631 * - remove completed entries from the table if their TTL has expired
donatien 0:8e01dca41002 632 *
donatien 0:8e01dca41002 633 * @param i index of the dns_table entry to check
donatien 0:8e01dca41002 634 */
donatien 0:8e01dca41002 635 static void
donatien 0:8e01dca41002 636 dns_check_entry(u8_t i)
donatien 0:8e01dca41002 637 {
donatien 0:8e01dca41002 638 err_t err;
donatien 0:8e01dca41002 639 struct dns_table_entry *pEntry = &dns_table[i];
donatien 0:8e01dca41002 640
donatien 0:8e01dca41002 641 LWIP_ASSERT("array index out of bounds", i < DNS_TABLE_SIZE);
donatien 0:8e01dca41002 642
donatien 0:8e01dca41002 643 switch(pEntry->state) {
donatien 0:8e01dca41002 644
donatien 0:8e01dca41002 645 case DNS_STATE_NEW: {
donatien 0:8e01dca41002 646 /* initialize new entry */
donatien 0:8e01dca41002 647 pEntry->state = DNS_STATE_ASKING;
donatien 0:8e01dca41002 648 pEntry->numdns = 0;
donatien 0:8e01dca41002 649 pEntry->tmr = 1;
donatien 0:8e01dca41002 650 pEntry->retries = 0;
donatien 0:8e01dca41002 651
donatien 0:8e01dca41002 652 /* send DNS packet for this entry */
donatien 0:8e01dca41002 653 err = dns_send(pEntry->numdns, pEntry->name, i);
donatien 0:8e01dca41002 654 if (err != ERR_OK) {
donatien 0:8e01dca41002 655 LWIP_DEBUGF(DNS_DEBUG | LWIP_DBG_LEVEL_WARNING,
donatien 0:8e01dca41002 656 ("dns_send returned error: %s\n", lwip_strerr(err)));
donatien 0:8e01dca41002 657 }
donatien 0:8e01dca41002 658 break;
donatien 0:8e01dca41002 659 }
donatien 0:8e01dca41002 660
donatien 0:8e01dca41002 661 case DNS_STATE_ASKING: {
donatien 0:8e01dca41002 662 if (--pEntry->tmr == 0) {
donatien 0:8e01dca41002 663 if (++pEntry->retries == DNS_MAX_RETRIES) {
donatien 0:8e01dca41002 664 if ((pEntry->numdns+1<DNS_MAX_SERVERS) && !ip_addr_isany(&dns_servers[pEntry->numdns+1])) {
donatien 0:8e01dca41002 665 /* change of server */
donatien 0:8e01dca41002 666 pEntry->numdns++;
donatien 0:8e01dca41002 667 pEntry->tmr = 1;
donatien 0:8e01dca41002 668 pEntry->retries = 0;
donatien 0:8e01dca41002 669 break;
donatien 0:8e01dca41002 670 } else {
donatien 0:8e01dca41002 671 LWIP_DEBUGF(DNS_DEBUG, ("dns_check_entry: \"%s\": timeout\n", pEntry->name));
donatien 0:8e01dca41002 672 /* call specified callback function if provided */
donatien 0:8e01dca41002 673 if (pEntry->found)
donatien 0:8e01dca41002 674 (*pEntry->found)(pEntry->name, NULL, pEntry->arg);
donatien 0:8e01dca41002 675 /* flush this entry */
donatien 0:8e01dca41002 676 pEntry->state = DNS_STATE_UNUSED;
donatien 0:8e01dca41002 677 pEntry->found = NULL;
donatien 0:8e01dca41002 678 break;
donatien 0:8e01dca41002 679 }
donatien 0:8e01dca41002 680 }
donatien 0:8e01dca41002 681
donatien 0:8e01dca41002 682 /* wait longer for the next retry */
donatien 0:8e01dca41002 683 pEntry->tmr = pEntry->retries;
donatien 0:8e01dca41002 684
donatien 0:8e01dca41002 685 /* send DNS packet for this entry */
donatien 0:8e01dca41002 686 err = dns_send(pEntry->numdns, pEntry->name, i);
donatien 0:8e01dca41002 687 if (err != ERR_OK) {
donatien 0:8e01dca41002 688 LWIP_DEBUGF(DNS_DEBUG | LWIP_DBG_LEVEL_WARNING,
donatien 0:8e01dca41002 689 ("dns_send returned error: %s\n", lwip_strerr(err)));
donatien 0:8e01dca41002 690 }
donatien 0:8e01dca41002 691 }
donatien 0:8e01dca41002 692 break;
donatien 0:8e01dca41002 693 }
donatien 0:8e01dca41002 694
donatien 0:8e01dca41002 695 case DNS_STATE_DONE: {
donatien 0:8e01dca41002 696 /* if the time to live is nul */
donatien 0:8e01dca41002 697 if (--pEntry->ttl == 0) {
donatien 0:8e01dca41002 698 LWIP_DEBUGF(DNS_DEBUG, ("dns_check_entry: \"%s\": flush\n", pEntry->name));
donatien 0:8e01dca41002 699 /* flush this entry */
donatien 0:8e01dca41002 700 pEntry->state = DNS_STATE_UNUSED;
donatien 0:8e01dca41002 701 pEntry->found = NULL;
donatien 0:8e01dca41002 702 }
donatien 0:8e01dca41002 703 break;
donatien 0:8e01dca41002 704 }
donatien 0:8e01dca41002 705 case DNS_STATE_UNUSED:
donatien 0:8e01dca41002 706 /* nothing to do */
donatien 0:8e01dca41002 707 break;
donatien 0:8e01dca41002 708 default:
donatien 0:8e01dca41002 709 LWIP_ASSERT("unknown dns_table entry state:", 0);
donatien 0:8e01dca41002 710 break;
donatien 0:8e01dca41002 711 }
donatien 0:8e01dca41002 712 }
donatien 0:8e01dca41002 713
donatien 0:8e01dca41002 714 /**
donatien 0:8e01dca41002 715 * Call dns_check_entry for each entry in dns_table - check all entries.
donatien 0:8e01dca41002 716 */
donatien 0:8e01dca41002 717 static void
donatien 0:8e01dca41002 718 dns_check_entries(void)
donatien 0:8e01dca41002 719 {
donatien 0:8e01dca41002 720 u8_t i;
donatien 0:8e01dca41002 721
donatien 0:8e01dca41002 722 for (i = 0; i < DNS_TABLE_SIZE; ++i) {
donatien 0:8e01dca41002 723 dns_check_entry(i);
donatien 0:8e01dca41002 724 }
donatien 0:8e01dca41002 725 }
donatien 0:8e01dca41002 726
donatien 0:8e01dca41002 727 /**
donatien 0:8e01dca41002 728 * Receive input function for DNS response packets arriving for the dns UDP pcb.
donatien 0:8e01dca41002 729 *
donatien 0:8e01dca41002 730 * @params see udp.h
donatien 0:8e01dca41002 731 */
donatien 0:8e01dca41002 732 static void
donatien 0:8e01dca41002 733 dns_recv(void *arg, struct udp_pcb *pcb, struct pbuf *p, ip_addr_t *addr, u16_t port)
donatien 0:8e01dca41002 734 {
donatien 0:8e01dca41002 735 u16_t i;
donatien 0:8e01dca41002 736 char *pHostname;
donatien 0:8e01dca41002 737 struct dns_hdr *hdr;
donatien 0:8e01dca41002 738 struct dns_answer ans;
donatien 0:8e01dca41002 739 struct dns_table_entry *pEntry;
donatien 0:8e01dca41002 740 u16_t nquestions, nanswers;
donatien 0:8e01dca41002 741
donatien 0:8e01dca41002 742 LWIP_UNUSED_ARG(arg);
donatien 0:8e01dca41002 743 LWIP_UNUSED_ARG(pcb);
donatien 0:8e01dca41002 744 LWIP_UNUSED_ARG(addr);
donatien 0:8e01dca41002 745 LWIP_UNUSED_ARG(port);
donatien 0:8e01dca41002 746
donatien 0:8e01dca41002 747 /* is the dns message too big ? */
donatien 0:8e01dca41002 748 if (p->tot_len > DNS_MSG_SIZE) {
donatien 0:8e01dca41002 749 LWIP_DEBUGF(DNS_DEBUG, ("dns_recv: pbuf too big\n"));
donatien 0:8e01dca41002 750 /* free pbuf and return */
donatien 0:8e01dca41002 751 goto memerr;
donatien 0:8e01dca41002 752 }
donatien 0:8e01dca41002 753
donatien 0:8e01dca41002 754 /* is the dns message big enough ? */
donatien 0:8e01dca41002 755 if (p->tot_len < (SIZEOF_DNS_HDR + SIZEOF_DNS_QUERY + SIZEOF_DNS_ANSWER)) {
donatien 0:8e01dca41002 756 LWIP_DEBUGF(DNS_DEBUG, ("dns_recv: pbuf too small\n"));
donatien 0:8e01dca41002 757 /* free pbuf and return */
donatien 0:8e01dca41002 758 goto memerr;
donatien 0:8e01dca41002 759 }
donatien 0:8e01dca41002 760
donatien 0:8e01dca41002 761 /* copy dns payload inside static buffer for processing */
donatien 0:8e01dca41002 762 if (pbuf_copy_partial(p, dns_payload, p->tot_len, 0) == p->tot_len) {
donatien 0:8e01dca41002 763 /* The ID in the DNS header should be our entry into the name table. */
donatien 0:8e01dca41002 764 hdr = (struct dns_hdr*)dns_payload;
donatien 0:8e01dca41002 765 i = htons(hdr->id);
donatien 0:8e01dca41002 766 if (i < DNS_TABLE_SIZE) {
donatien 0:8e01dca41002 767 pEntry = &dns_table[i];
donatien 0:8e01dca41002 768 if(pEntry->state == DNS_STATE_ASKING) {
donatien 0:8e01dca41002 769 /* This entry is now completed. */
donatien 0:8e01dca41002 770 pEntry->state = DNS_STATE_DONE;
donatien 0:8e01dca41002 771 pEntry->err = hdr->flags2 & DNS_FLAG2_ERR_MASK;
donatien 0:8e01dca41002 772
donatien 0:8e01dca41002 773 /* We only care about the question(s) and the answers. The authrr
donatien 0:8e01dca41002 774 and the extrarr are simply discarded. */
donatien 0:8e01dca41002 775 nquestions = htons(hdr->numquestions);
donatien 0:8e01dca41002 776 nanswers = htons(hdr->numanswers);
donatien 0:8e01dca41002 777
donatien 0:8e01dca41002 778 /* Check for error. If so, call callback to inform. */
donatien 0:8e01dca41002 779 if (((hdr->flags1 & DNS_FLAG1_RESPONSE) == 0) || (pEntry->err != 0) || (nquestions != 1)) {
donatien 0:8e01dca41002 780 LWIP_DEBUGF(DNS_DEBUG, ("dns_recv: \"%s\": error in flags\n", pEntry->name));
donatien 0:8e01dca41002 781 /* call callback to indicate error, clean up memory and return */
donatien 0:8e01dca41002 782 goto responseerr;
donatien 0:8e01dca41002 783 }
donatien 0:8e01dca41002 784
donatien 0:8e01dca41002 785 #if DNS_DOES_NAME_CHECK
donatien 0:8e01dca41002 786 /* Check if the name in the "question" part match with the name in the entry. */
donatien 0:8e01dca41002 787 if (dns_compare_name((unsigned char *)(pEntry->name), (unsigned char *)dns_payload + SIZEOF_DNS_HDR) != 0) {
donatien 0:8e01dca41002 788 LWIP_DEBUGF(DNS_DEBUG, ("dns_recv: \"%s\": response not match to query\n", pEntry->name));
donatien 0:8e01dca41002 789 /* call callback to indicate error, clean up memory and return */
donatien 0:8e01dca41002 790 goto responseerr;
donatien 0:8e01dca41002 791 }
donatien 0:8e01dca41002 792 #endif /* DNS_DOES_NAME_CHECK */
donatien 0:8e01dca41002 793
donatien 0:8e01dca41002 794 /* Skip the name in the "question" part */
donatien 0:8e01dca41002 795 pHostname = (char *) dns_parse_name((unsigned char *)dns_payload + SIZEOF_DNS_HDR) + SIZEOF_DNS_QUERY;
donatien 0:8e01dca41002 796
donatien 0:8e01dca41002 797 while (nanswers > 0) {
donatien 0:8e01dca41002 798 /* skip answer resource record's host name */
donatien 0:8e01dca41002 799 pHostname = (char *) dns_parse_name((unsigned char *)pHostname);
donatien 0:8e01dca41002 800
donatien 0:8e01dca41002 801 /* Check for IP address type and Internet class. Others are discarded. */
donatien 0:8e01dca41002 802 SMEMCPY(&ans, pHostname, SIZEOF_DNS_ANSWER);
donatien 0:8e01dca41002 803 if((ans.type == PP_HTONS(DNS_RRTYPE_A)) && (ans.cls == PP_HTONS(DNS_RRCLASS_IN)) &&
donatien 0:8e01dca41002 804 (ans.len == PP_HTONS(sizeof(ip_addr_t))) ) {
donatien 0:8e01dca41002 805 /* read the answer resource record's TTL, and maximize it if needed */
donatien 0:8e01dca41002 806 pEntry->ttl = ntohl(ans.ttl);
donatien 0:8e01dca41002 807 if (pEntry->ttl > DNS_MAX_TTL) {
donatien 0:8e01dca41002 808 pEntry->ttl = DNS_MAX_TTL;
donatien 0:8e01dca41002 809 }
donatien 0:8e01dca41002 810 /* read the IP address after answer resource record's header */
donatien 0:8e01dca41002 811 SMEMCPY(&(pEntry->ipaddr), (pHostname+SIZEOF_DNS_ANSWER), sizeof(ip_addr_t));
donatien 0:8e01dca41002 812 LWIP_DEBUGF(DNS_DEBUG, ("dns_recv: \"%s\": response = ", pEntry->name));
donatien 0:8e01dca41002 813 ip_addr_debug_print(DNS_DEBUG, (&(pEntry->ipaddr)));
donatien 0:8e01dca41002 814 LWIP_DEBUGF(DNS_DEBUG, ("\n"));
donatien 0:8e01dca41002 815 /* call specified callback function if provided */
donatien 0:8e01dca41002 816 if (pEntry->found) {
donatien 0:8e01dca41002 817 (*pEntry->found)(pEntry->name, &pEntry->ipaddr, pEntry->arg);
donatien 0:8e01dca41002 818 }
donatien 0:8e01dca41002 819 /* deallocate memory and return */
donatien 0:8e01dca41002 820 goto memerr;
donatien 0:8e01dca41002 821 } else {
donatien 0:8e01dca41002 822 pHostname = pHostname + SIZEOF_DNS_ANSWER + htons(ans.len);
donatien 0:8e01dca41002 823 }
donatien 0:8e01dca41002 824 --nanswers;
donatien 0:8e01dca41002 825 }
donatien 0:8e01dca41002 826 LWIP_DEBUGF(DNS_DEBUG, ("dns_recv: \"%s\": error in response\n", pEntry->name));
donatien 0:8e01dca41002 827 /* call callback to indicate error, clean up memory and return */
donatien 0:8e01dca41002 828 goto responseerr;
donatien 0:8e01dca41002 829 }
donatien 0:8e01dca41002 830 }
donatien 0:8e01dca41002 831 }
donatien 0:8e01dca41002 832
donatien 0:8e01dca41002 833 /* deallocate memory and return */
donatien 0:8e01dca41002 834 goto memerr;
donatien 0:8e01dca41002 835
donatien 0:8e01dca41002 836 responseerr:
donatien 0:8e01dca41002 837 /* ERROR: call specified callback function with NULL as name to indicate an error */
donatien 0:8e01dca41002 838 if (pEntry->found) {
donatien 0:8e01dca41002 839 (*pEntry->found)(pEntry->name, NULL, pEntry->arg);
donatien 0:8e01dca41002 840 }
donatien 0:8e01dca41002 841 /* flush this entry */
donatien 0:8e01dca41002 842 pEntry->state = DNS_STATE_UNUSED;
donatien 0:8e01dca41002 843 pEntry->found = NULL;
donatien 0:8e01dca41002 844
donatien 0:8e01dca41002 845 memerr:
donatien 0:8e01dca41002 846 /* free pbuf */
donatien 0:8e01dca41002 847 pbuf_free(p);
donatien 0:8e01dca41002 848 return;
donatien 0:8e01dca41002 849 }
donatien 0:8e01dca41002 850
donatien 0:8e01dca41002 851 /**
donatien 0:8e01dca41002 852 * Queues a new hostname to resolve and sends out a DNS query for that hostname
donatien 0:8e01dca41002 853 *
donatien 0:8e01dca41002 854 * @param name the hostname that is to be queried
donatien 0:8e01dca41002 855 * @param found a callback founction to be called on success, failure or timeout
donatien 0:8e01dca41002 856 * @param callback_arg argument to pass to the callback function
donatien 0:8e01dca41002 857 * @return @return a err_t return code.
donatien 0:8e01dca41002 858 */
donatien 0:8e01dca41002 859 static err_t
donatien 0:8e01dca41002 860 dns_enqueue(const char *name, dns_found_callback found, void *callback_arg)
donatien 0:8e01dca41002 861 {
donatien 0:8e01dca41002 862 u8_t i;
donatien 0:8e01dca41002 863 u8_t lseq, lseqi;
donatien 0:8e01dca41002 864 struct dns_table_entry *pEntry = NULL;
donatien 0:8e01dca41002 865 size_t namelen;
donatien 0:8e01dca41002 866
donatien 0:8e01dca41002 867 /* search an unused entry, or the oldest one */
donatien 0:8e01dca41002 868 lseq = lseqi = 0;
donatien 0:8e01dca41002 869 for (i = 0; i < DNS_TABLE_SIZE; ++i) {
donatien 0:8e01dca41002 870 pEntry = &dns_table[i];
donatien 0:8e01dca41002 871 /* is it an unused entry ? */
donatien 0:8e01dca41002 872 if (pEntry->state == DNS_STATE_UNUSED)
donatien 0:8e01dca41002 873 break;
donatien 0:8e01dca41002 874
donatien 0:8e01dca41002 875 /* check if this is the oldest completed entry */
donatien 0:8e01dca41002 876 if (pEntry->state == DNS_STATE_DONE) {
donatien 0:8e01dca41002 877 if ((dns_seqno - pEntry->seqno) > lseq) {
donatien 0:8e01dca41002 878 lseq = dns_seqno - pEntry->seqno;
donatien 0:8e01dca41002 879 lseqi = i;
donatien 0:8e01dca41002 880 }
donatien 0:8e01dca41002 881 }
donatien 0:8e01dca41002 882 }
donatien 0:8e01dca41002 883
donatien 0:8e01dca41002 884 /* if we don't have found an unused entry, use the oldest completed one */
donatien 0:8e01dca41002 885 if (i == DNS_TABLE_SIZE) {
donatien 0:8e01dca41002 886 if ((lseqi >= DNS_TABLE_SIZE) || (dns_table[lseqi].state != DNS_STATE_DONE)) {
donatien 0:8e01dca41002 887 /* no entry can't be used now, table is full */
donatien 0:8e01dca41002 888 LWIP_DEBUGF(DNS_DEBUG, ("dns_enqueue: \"%s\": DNS entries table is full\n", name));
donatien 0:8e01dca41002 889 return ERR_MEM;
donatien 0:8e01dca41002 890 } else {
donatien 0:8e01dca41002 891 /* use the oldest completed one */
donatien 0:8e01dca41002 892 i = lseqi;
donatien 0:8e01dca41002 893 pEntry = &dns_table[i];
donatien 0:8e01dca41002 894 }
donatien 0:8e01dca41002 895 }
donatien 0:8e01dca41002 896
donatien 0:8e01dca41002 897 /* use this entry */
donatien 0:8e01dca41002 898 LWIP_DEBUGF(DNS_DEBUG, ("dns_enqueue: \"%s\": use DNS entry %"U16_F"\n", name, (u16_t)(i)));
donatien 0:8e01dca41002 899
donatien 0:8e01dca41002 900 /* fill the entry */
donatien 0:8e01dca41002 901 pEntry->state = DNS_STATE_NEW;
donatien 0:8e01dca41002 902 pEntry->seqno = dns_seqno++;
donatien 0:8e01dca41002 903 pEntry->found = found;
donatien 0:8e01dca41002 904 pEntry->arg = callback_arg;
donatien 0:8e01dca41002 905 namelen = LWIP_MIN(strlen(name), DNS_MAX_NAME_LENGTH-1);
donatien 0:8e01dca41002 906 MEMCPY(pEntry->name, name, namelen);
donatien 0:8e01dca41002 907 pEntry->name[namelen] = 0;
donatien 0:8e01dca41002 908
donatien 0:8e01dca41002 909 /* force to send query without waiting timer */
donatien 0:8e01dca41002 910 dns_check_entry(i);
donatien 0:8e01dca41002 911
donatien 0:8e01dca41002 912 /* dns query is enqueued */
donatien 0:8e01dca41002 913 return ERR_INPROGRESS;
donatien 0:8e01dca41002 914 }
donatien 0:8e01dca41002 915
donatien 0:8e01dca41002 916 /**
donatien 0:8e01dca41002 917 * Resolve a hostname (string) into an IP address.
donatien 0:8e01dca41002 918 * NON-BLOCKING callback version for use with raw API!!!
donatien 0:8e01dca41002 919 *
donatien 0:8e01dca41002 920 * Returns immediately with one of err_t return codes:
donatien 0:8e01dca41002 921 * - ERR_OK if hostname is a valid IP address string or the host
donatien 0:8e01dca41002 922 * name is already in the local names table.
donatien 0:8e01dca41002 923 * - ERR_INPROGRESS enqueue a request to be sent to the DNS server
donatien 0:8e01dca41002 924 * for resolution if no errors are present.
donatien 0:8e01dca41002 925 * - ERR_ARG: dns client not initialized or invalid hostname
donatien 0:8e01dca41002 926 *
donatien 0:8e01dca41002 927 * @param hostname the hostname that is to be queried
donatien 0:8e01dca41002 928 * @param addr pointer to a ip_addr_t where to store the address if it is already
donatien 0:8e01dca41002 929 * cached in the dns_table (only valid if ERR_OK is returned!)
donatien 0:8e01dca41002 930 * @param found a callback function to be called on success, failure or timeout (only if
donatien 0:8e01dca41002 931 * ERR_INPROGRESS is returned!)
donatien 0:8e01dca41002 932 * @param callback_arg argument to pass to the callback function
donatien 0:8e01dca41002 933 * @return a err_t return code.
donatien 0:8e01dca41002 934 */
donatien 0:8e01dca41002 935 err_t
donatien 0:8e01dca41002 936 dns_gethostbyname(const char *hostname, ip_addr_t *addr, dns_found_callback found,
donatien 0:8e01dca41002 937 void *callback_arg)
donatien 0:8e01dca41002 938 {
donatien 0:8e01dca41002 939 u32_t ipaddr;
donatien 0:8e01dca41002 940 /* not initialized or no valid server yet, or invalid addr pointer
donatien 0:8e01dca41002 941 * or invalid hostname or invalid hostname length */
donatien 0:8e01dca41002 942 if ((dns_pcb == NULL) || (addr == NULL) ||
donatien 0:8e01dca41002 943 (!hostname) || (!hostname[0]) ||
donatien 0:8e01dca41002 944 (strlen(hostname) >= DNS_MAX_NAME_LENGTH)) {
donatien 0:8e01dca41002 945 return ERR_ARG;
donatien 0:8e01dca41002 946 }
donatien 0:8e01dca41002 947
donatien 0:8e01dca41002 948 #if LWIP_HAVE_LOOPIF
donatien 0:8e01dca41002 949 if (strcmp(hostname, "localhost")==0) {
donatien 0:8e01dca41002 950 ip_addr_set_loopback(addr);
donatien 0:8e01dca41002 951 return ERR_OK;
donatien 0:8e01dca41002 952 }
donatien 0:8e01dca41002 953 #endif /* LWIP_HAVE_LOOPIF */
donatien 0:8e01dca41002 954
donatien 0:8e01dca41002 955 /* host name already in octet notation? set ip addr and return ERR_OK */
donatien 0:8e01dca41002 956 ipaddr = ipaddr_addr(hostname);
donatien 0:8e01dca41002 957 if (ipaddr == IPADDR_NONE) {
donatien 0:8e01dca41002 958 /* already have this address cached? */
donatien 0:8e01dca41002 959 ipaddr = dns_lookup(hostname);
donatien 0:8e01dca41002 960 }
donatien 0:8e01dca41002 961 if (ipaddr != IPADDR_NONE) {
donatien 0:8e01dca41002 962 ip4_addr_set_u32(addr, ipaddr);
donatien 0:8e01dca41002 963 return ERR_OK;
donatien 0:8e01dca41002 964 }
donatien 0:8e01dca41002 965
donatien 0:8e01dca41002 966 /* queue query with specified callback */
donatien 0:8e01dca41002 967 return dns_enqueue(hostname, found, callback_arg);
donatien 0:8e01dca41002 968 }
donatien 0:8e01dca41002 969
donatien 0:8e01dca41002 970 #endif /* LWIP_DNS */