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Dependencies:   mbed

NetServices/lwip/core/dns.c@1:f5ac63519541, 2014-03-05 (annotated)

Committer:
Michael J. Spencer
Date:
Wed Mar 05 06:14:02 2014 -0800
Revision:
1:f5ac63519541
Initial commit.

Who changed what in which revision?

UserRevisionLine numberNew contents of line
Michael J. Spencer 1:f5ac63519541 1 /**
Michael J. Spencer 1:f5ac63519541 2 * @file
Michael J. Spencer 1:f5ac63519541 3 * DNS - host name to IP address resolver.
Michael J. Spencer 1:f5ac63519541 4 *
Michael J. Spencer 1:f5ac63519541 5 */
Michael J. Spencer 1:f5ac63519541 6
Michael J. Spencer 1:f5ac63519541 7 /**
Michael J. Spencer 1:f5ac63519541 8
Michael J. Spencer 1:f5ac63519541 9 * This file implements a DNS host name to IP address resolver.
Michael J. Spencer 1:f5ac63519541 10
Michael J. Spencer 1:f5ac63519541 11 * Port to lwIP from uIP
Michael J. Spencer 1:f5ac63519541 12 * by Jim Pettinato April 2007
Michael J. Spencer 1:f5ac63519541 13
Michael J. Spencer 1:f5ac63519541 14 * uIP version Copyright (c) 2002-2003, Adam Dunkels.
Michael J. Spencer 1:f5ac63519541 15 * All rights reserved.
Michael J. Spencer 1:f5ac63519541 16 *
Michael J. Spencer 1:f5ac63519541 17 * Redistribution and use in source and binary forms, with or without
Michael J. Spencer 1:f5ac63519541 18 * modification, are permitted provided that the following conditions
Michael J. Spencer 1:f5ac63519541 19 * are met:
Michael J. Spencer 1:f5ac63519541 20 * 1. Redistributions of source code must retain the above copyright
Michael J. Spencer 1:f5ac63519541 21 * notice, this list of conditions and the following disclaimer.
Michael J. Spencer 1:f5ac63519541 22 * 2. Redistributions in binary form must reproduce the above copyright
Michael J. Spencer 1:f5ac63519541 23 * notice, this list of conditions and the following disclaimer in the
Michael J. Spencer 1:f5ac63519541 24 * documentation and/or other materials provided with the distribution.
Michael J. Spencer 1:f5ac63519541 25 * 3. The name of the author may not be used to endorse or promote
Michael J. Spencer 1:f5ac63519541 26 * products derived from this software without specific prior
Michael J. Spencer 1:f5ac63519541 27 * written permission.
Michael J. Spencer 1:f5ac63519541 28 *
Michael J. Spencer 1:f5ac63519541 29 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
Michael J. Spencer 1:f5ac63519541 30 * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
Michael J. Spencer 1:f5ac63519541 31 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
Michael J. Spencer 1:f5ac63519541 32 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
Michael J. Spencer 1:f5ac63519541 33 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
Michael J. Spencer 1:f5ac63519541 34 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
Michael J. Spencer 1:f5ac63519541 35 * GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
Michael J. Spencer 1:f5ac63519541 36 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
Michael J. Spencer 1:f5ac63519541 37 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
Michael J. Spencer 1:f5ac63519541 38 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
Michael J. Spencer 1:f5ac63519541 39 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
Michael J. Spencer 1:f5ac63519541 40 *
Michael J. Spencer 1:f5ac63519541 41 *
Michael J. Spencer 1:f5ac63519541 42 * DNS.C
Michael J. Spencer 1:f5ac63519541 43 *
Michael J. Spencer 1:f5ac63519541 44 * The lwIP DNS resolver functions are used to lookup a host name and
Michael J. Spencer 1:f5ac63519541 45 * map it to a numerical IP address. It maintains a list of resolved
Michael J. Spencer 1:f5ac63519541 46 * hostnames that can be queried with the dns_lookup() function.
Michael J. Spencer 1:f5ac63519541 47 * New hostnames can be resolved using the dns_query() function.
Michael J. Spencer 1:f5ac63519541 48 *
Michael J. Spencer 1:f5ac63519541 49 * The lwIP version of the resolver also adds a non-blocking version of
Michael J. Spencer 1:f5ac63519541 50 * gethostbyname() that will work with a raw API application. This function
Michael J. Spencer 1:f5ac63519541 51 * checks for an IP address string first and converts it if it is valid.
Michael J. Spencer 1:f5ac63519541 52 * gethostbyname() then does a dns_lookup() to see if the name is
Michael J. Spencer 1:f5ac63519541 53 * already in the table. If so, the IP is returned. If not, a query is
Michael J. Spencer 1:f5ac63519541 54 * issued and the function returns with a ERR_INPROGRESS status. The app
Michael J. Spencer 1:f5ac63519541 55 * using the dns client must then go into a waiting state.
Michael J. Spencer 1:f5ac63519541 56 *
Michael J. Spencer 1:f5ac63519541 57 * Once a hostname has been resolved (or found to be non-existent),
Michael J. Spencer 1:f5ac63519541 58 * the resolver code calls a specified callback function (which
Michael J. Spencer 1:f5ac63519541 59 * must be implemented by the module that uses the resolver).
Michael J. Spencer 1:f5ac63519541 60 */
Michael J. Spencer 1:f5ac63519541 61
Michael J. Spencer 1:f5ac63519541 62 /*-----------------------------------------------------------------------------
Michael J. Spencer 1:f5ac63519541 63 * RFC 1035 - Domain names - implementation and specification
Michael J. Spencer 1:f5ac63519541 64 * RFC 2181 - Clarifications to the DNS Specification
Michael J. Spencer 1:f5ac63519541 65 *----------------------------------------------------------------------------*/
Michael J. Spencer 1:f5ac63519541 66
Michael J. Spencer 1:f5ac63519541 67 /** @todo: define good default values (rfc compliance) */
Michael J. Spencer 1:f5ac63519541 68 /** @todo: improve answer parsing, more checkings... */
Michael J. Spencer 1:f5ac63519541 69 /** @todo: check RFC1035 - 7.3. Processing responses */
Michael J. Spencer 1:f5ac63519541 70
Michael J. Spencer 1:f5ac63519541 71 /*-----------------------------------------------------------------------------
Michael J. Spencer 1:f5ac63519541 72 * Includes
Michael J. Spencer 1:f5ac63519541 73 *----------------------------------------------------------------------------*/
Michael J. Spencer 1:f5ac63519541 74
Michael J. Spencer 1:f5ac63519541 75 #include "lwip/opt.h"
Michael J. Spencer 1:f5ac63519541 76
Michael J. Spencer 1:f5ac63519541 77 #if LWIP_DNS /* don't build if not configured for use in lwipopts.h */
Michael J. Spencer 1:f5ac63519541 78
Michael J. Spencer 1:f5ac63519541 79 #include "lwip/udp.h"
Michael J. Spencer 1:f5ac63519541 80 #include "lwip/mem.h"
Michael J. Spencer 1:f5ac63519541 81 #include "lwip/memp.h"
Michael J. Spencer 1:f5ac63519541 82 #include "lwip/dns.h"
Michael J. Spencer 1:f5ac63519541 83
Michael J. Spencer 1:f5ac63519541 84 #include <string.h>
Michael J. Spencer 1:f5ac63519541 85
Michael J. Spencer 1:f5ac63519541 86 /** DNS server IP address */
Michael J. Spencer 1:f5ac63519541 87 #ifndef DNS_SERVER_ADDRESS
Michael J. Spencer 1:f5ac63519541 88 #define DNS_SERVER_ADDRESS(ipaddr) (ip4_addr_set_u32(ipaddr, ipaddr_addr("208.67.222.222"))) /* resolver1.opendns.com */
Michael J. Spencer 1:f5ac63519541 89 #endif
Michael J. Spencer 1:f5ac63519541 90
Michael J. Spencer 1:f5ac63519541 91 /** DNS server port address */
Michael J. Spencer 1:f5ac63519541 92 #ifndef DNS_SERVER_PORT
Michael J. Spencer 1:f5ac63519541 93 #define DNS_SERVER_PORT 53
Michael J. Spencer 1:f5ac63519541 94 #endif
Michael J. Spencer 1:f5ac63519541 95
Michael J. Spencer 1:f5ac63519541 96 /** DNS maximum number of retries when asking for a name, before "timeout". */
Michael J. Spencer 1:f5ac63519541 97 #ifndef DNS_MAX_RETRIES
Michael J. Spencer 1:f5ac63519541 98 #define DNS_MAX_RETRIES 4
Michael J. Spencer 1:f5ac63519541 99 #endif
Michael J. Spencer 1:f5ac63519541 100
Michael J. Spencer 1:f5ac63519541 101 /** DNS resource record max. TTL (one week as default) */
Michael J. Spencer 1:f5ac63519541 102 #ifndef DNS_MAX_TTL
Michael J. Spencer 1:f5ac63519541 103 #define DNS_MAX_TTL 604800
Michael J. Spencer 1:f5ac63519541 104 #endif
Michael J. Spencer 1:f5ac63519541 105
Michael J. Spencer 1:f5ac63519541 106 /* DNS protocol flags */
Michael J. Spencer 1:f5ac63519541 107 #define DNS_FLAG1_RESPONSE 0x80
Michael J. Spencer 1:f5ac63519541 108 #define DNS_FLAG1_OPCODE_STATUS 0x10
Michael J. Spencer 1:f5ac63519541 109 #define DNS_FLAG1_OPCODE_INVERSE 0x08
Michael J. Spencer 1:f5ac63519541 110 #define DNS_FLAG1_OPCODE_STANDARD 0x00
Michael J. Spencer 1:f5ac63519541 111 #define DNS_FLAG1_AUTHORATIVE 0x04
Michael J. Spencer 1:f5ac63519541 112 #define DNS_FLAG1_TRUNC 0x02
Michael J. Spencer 1:f5ac63519541 113 #define DNS_FLAG1_RD 0x01
Michael J. Spencer 1:f5ac63519541 114 #define DNS_FLAG2_RA 0x80
Michael J. Spencer 1:f5ac63519541 115 #define DNS_FLAG2_ERR_MASK 0x0f
Michael J. Spencer 1:f5ac63519541 116 #define DNS_FLAG2_ERR_NONE 0x00
Michael J. Spencer 1:f5ac63519541 117 #define DNS_FLAG2_ERR_NAME 0x03
Michael J. Spencer 1:f5ac63519541 118
Michael J. Spencer 1:f5ac63519541 119 /* DNS protocol states */
Michael J. Spencer 1:f5ac63519541 120 #define DNS_STATE_UNUSED 0
Michael J. Spencer 1:f5ac63519541 121 #define DNS_STATE_NEW 1
Michael J. Spencer 1:f5ac63519541 122 #define DNS_STATE_ASKING 2
Michael J. Spencer 1:f5ac63519541 123 #define DNS_STATE_DONE 3
Michael J. Spencer 1:f5ac63519541 124
Michael J. Spencer 1:f5ac63519541 125 #ifdef PACK_STRUCT_USE_INCLUDES
Michael J. Spencer 1:f5ac63519541 126 # include "arch/bpstruct.h"
Michael J. Spencer 1:f5ac63519541 127 #endif
Michael J. Spencer 1:f5ac63519541 128 PACK_STRUCT_BEGIN
Michael J. Spencer 1:f5ac63519541 129 /** DNS message header */
Michael J. Spencer 1:f5ac63519541 130 struct dns_hdr {
Michael J. Spencer 1:f5ac63519541 131 PACK_STRUCT_FIELD(u16_t id);
Michael J. Spencer 1:f5ac63519541 132 PACK_STRUCT_FIELD(u8_t flags1);
Michael J. Spencer 1:f5ac63519541 133 PACK_STRUCT_FIELD(u8_t flags2);
Michael J. Spencer 1:f5ac63519541 134 PACK_STRUCT_FIELD(u16_t numquestions);
Michael J. Spencer 1:f5ac63519541 135 PACK_STRUCT_FIELD(u16_t numanswers);
Michael J. Spencer 1:f5ac63519541 136 PACK_STRUCT_FIELD(u16_t numauthrr);
Michael J. Spencer 1:f5ac63519541 137 PACK_STRUCT_FIELD(u16_t numextrarr);
Michael J. Spencer 1:f5ac63519541 138 } PACK_STRUCT_STRUCT;
Michael J. Spencer 1:f5ac63519541 139 PACK_STRUCT_END
Michael J. Spencer 1:f5ac63519541 140 #ifdef PACK_STRUCT_USE_INCLUDES
Michael J. Spencer 1:f5ac63519541 141 # include "arch/epstruct.h"
Michael J. Spencer 1:f5ac63519541 142 #endif
Michael J. Spencer 1:f5ac63519541 143 #define SIZEOF_DNS_HDR 12
Michael J. Spencer 1:f5ac63519541 144
Michael J. Spencer 1:f5ac63519541 145 /** DNS query message structure.
Michael J. Spencer 1:f5ac63519541 146 No packing needed: only used locally on the stack. */
Michael J. Spencer 1:f5ac63519541 147 struct dns_query {
Michael J. Spencer 1:f5ac63519541 148 /* DNS query record starts with either a domain name or a pointer
Michael J. Spencer 1:f5ac63519541 149 to a name already present somewhere in the packet. */
Michael J. Spencer 1:f5ac63519541 150 u16_t type;
Michael J. Spencer 1:f5ac63519541 151 u16_t cls;
Michael J. Spencer 1:f5ac63519541 152 };
Michael J. Spencer 1:f5ac63519541 153 #define SIZEOF_DNS_QUERY 4
Michael J. Spencer 1:f5ac63519541 154
Michael J. Spencer 1:f5ac63519541 155 /** DNS answer message structure.
Michael J. Spencer 1:f5ac63519541 156 No packing needed: only used locally on the stack. */
Michael J. Spencer 1:f5ac63519541 157 struct dns_answer {
Michael J. Spencer 1:f5ac63519541 158 /* DNS answer record starts with either a domain name or a pointer
Michael J. Spencer 1:f5ac63519541 159 to a name already present somewhere in the packet. */
Michael J. Spencer 1:f5ac63519541 160 u16_t type;
Michael J. Spencer 1:f5ac63519541 161 u16_t cls;
Michael J. Spencer 1:f5ac63519541 162 u32_t ttl;
Michael J. Spencer 1:f5ac63519541 163 u16_t len;
Michael J. Spencer 1:f5ac63519541 164 };
Michael J. Spencer 1:f5ac63519541 165 #define SIZEOF_DNS_ANSWER 10
Michael J. Spencer 1:f5ac63519541 166
Michael J. Spencer 1:f5ac63519541 167 /** DNS table entry */
Michael J. Spencer 1:f5ac63519541 168 struct dns_table_entry {
Michael J. Spencer 1:f5ac63519541 169 u8_t state;
Michael J. Spencer 1:f5ac63519541 170 u8_t numdns;
Michael J. Spencer 1:f5ac63519541 171 u8_t tmr;
Michael J. Spencer 1:f5ac63519541 172 u8_t retries;
Michael J. Spencer 1:f5ac63519541 173 u8_t seqno;
Michael J. Spencer 1:f5ac63519541 174 u8_t err;
Michael J. Spencer 1:f5ac63519541 175 u32_t ttl;
Michael J. Spencer 1:f5ac63519541 176 char name[DNS_MAX_NAME_LENGTH];
Michael J. Spencer 1:f5ac63519541 177 ip_addr_t ipaddr;
Michael J. Spencer 1:f5ac63519541 178 /* pointer to callback on DNS query done */
Michael J. Spencer 1:f5ac63519541 179 dns_found_callback found;
Michael J. Spencer 1:f5ac63519541 180 void *arg;
Michael J. Spencer 1:f5ac63519541 181 };
Michael J. Spencer 1:f5ac63519541 182
Michael J. Spencer 1:f5ac63519541 183 #if DNS_LOCAL_HOSTLIST
Michael J. Spencer 1:f5ac63519541 184
Michael J. Spencer 1:f5ac63519541 185 #if DNS_LOCAL_HOSTLIST_IS_DYNAMIC
Michael J. Spencer 1:f5ac63519541 186 /** Local host-list. For hostnames in this list, no
Michael J. Spencer 1:f5ac63519541 187 * external name resolution is performed */
Michael J. Spencer 1:f5ac63519541 188 static struct local_hostlist_entry *local_hostlist_dynamic;
Michael J. Spencer 1:f5ac63519541 189 #else /* DNS_LOCAL_HOSTLIST_IS_DYNAMIC */
Michael J. Spencer 1:f5ac63519541 190
Michael J. Spencer 1:f5ac63519541 191 /** Defining this allows the local_hostlist_static to be placed in a different
Michael J. Spencer 1:f5ac63519541 192 * linker section (e.g. FLASH) */
Michael J. Spencer 1:f5ac63519541 193 #ifndef DNS_LOCAL_HOSTLIST_STORAGE_PRE
Michael J. Spencer 1:f5ac63519541 194 #define DNS_LOCAL_HOSTLIST_STORAGE_PRE static
Michael J. Spencer 1:f5ac63519541 195 #endif /* DNS_LOCAL_HOSTLIST_STORAGE_PRE */
Michael J. Spencer 1:f5ac63519541 196 /** Defining this allows the local_hostlist_static to be placed in a different
Michael J. Spencer 1:f5ac63519541 197 * linker section (e.g. FLASH) */
Michael J. Spencer 1:f5ac63519541 198 #ifndef DNS_LOCAL_HOSTLIST_STORAGE_POST
Michael J. Spencer 1:f5ac63519541 199 #define DNS_LOCAL_HOSTLIST_STORAGE_POST
Michael J. Spencer 1:f5ac63519541 200 #endif /* DNS_LOCAL_HOSTLIST_STORAGE_POST */
Michael J. Spencer 1:f5ac63519541 201 DNS_LOCAL_HOSTLIST_STORAGE_PRE struct local_hostlist_entry local_hostlist_static[]
Michael J. Spencer 1:f5ac63519541 202 DNS_LOCAL_HOSTLIST_STORAGE_POST = DNS_LOCAL_HOSTLIST_INIT;
Michael J. Spencer 1:f5ac63519541 203
Michael J. Spencer 1:f5ac63519541 204 #endif /* DNS_LOCAL_HOSTLIST_IS_DYNAMIC */
Michael J. Spencer 1:f5ac63519541 205
Michael J. Spencer 1:f5ac63519541 206 static void dns_init_local();
Michael J. Spencer 1:f5ac63519541 207 #endif /* DNS_LOCAL_HOSTLIST */
Michael J. Spencer 1:f5ac63519541 208
Michael J. Spencer 1:f5ac63519541 209
Michael J. Spencer 1:f5ac63519541 210 /* forward declarations */
Michael J. Spencer 1:f5ac63519541 211 static void dns_recv(void *s, struct udp_pcb *pcb, struct pbuf *p, ip_addr_t *addr, u16_t port);
Michael J. Spencer 1:f5ac63519541 212 static void dns_check_entries(void);
Michael J. Spencer 1:f5ac63519541 213
Michael J. Spencer 1:f5ac63519541 214 /*-----------------------------------------------------------------------------
Michael J. Spencer 1:f5ac63519541 215 * Globales
Michael J. Spencer 1:f5ac63519541 216 *----------------------------------------------------------------------------*/
Michael J. Spencer 1:f5ac63519541 217
Michael J. Spencer 1:f5ac63519541 218 /* DNS variables */
Michael J. Spencer 1:f5ac63519541 219 static struct udp_pcb *dns_pcb;
Michael J. Spencer 1:f5ac63519541 220 static u8_t dns_seqno;
Michael J. Spencer 1:f5ac63519541 221 static struct dns_table_entry dns_table[DNS_TABLE_SIZE];
Michael J. Spencer 1:f5ac63519541 222 static ip_addr_t dns_servers[DNS_MAX_SERVERS];
Michael J. Spencer 1:f5ac63519541 223 /** Contiguous buffer for processing responses */
Michael J. Spencer 1:f5ac63519541 224 static u8_t dns_payload_buffer[LWIP_MEM_ALIGN_BUFFER(DNS_MSG_SIZE)];
Michael J. Spencer 1:f5ac63519541 225 static u8_t* dns_payload;
Michael J. Spencer 1:f5ac63519541 226
Michael J. Spencer 1:f5ac63519541 227 /**
Michael J. Spencer 1:f5ac63519541 228 * Initialize the resolver: set up the UDP pcb and configure the default server
Michael J. Spencer 1:f5ac63519541 229 * (DNS_SERVER_ADDRESS).
Michael J. Spencer 1:f5ac63519541 230 */
Michael J. Spencer 1:f5ac63519541 231 void
Michael J. Spencer 1:f5ac63519541 232 dns_init()
Michael J. Spencer 1:f5ac63519541 233 {
Michael J. Spencer 1:f5ac63519541 234 ip_addr_t dnsserver;
Michael J. Spencer 1:f5ac63519541 235
Michael J. Spencer 1:f5ac63519541 236 dns_payload = (u8_t *)LWIP_MEM_ALIGN(dns_payload_buffer);
Michael J. Spencer 1:f5ac63519541 237
Michael J. Spencer 1:f5ac63519541 238 /* initialize default DNS server address */
Michael J. Spencer 1:f5ac63519541 239 DNS_SERVER_ADDRESS(&dnsserver);
Michael J. Spencer 1:f5ac63519541 240
Michael J. Spencer 1:f5ac63519541 241 LWIP_DEBUGF(DNS_DEBUG, ("dns_init: initializing\n"));
Michael J. Spencer 1:f5ac63519541 242
Michael J. Spencer 1:f5ac63519541 243 /* if dns client not yet initialized... */
Michael J. Spencer 1:f5ac63519541 244 if (dns_pcb == NULL) {
Michael J. Spencer 1:f5ac63519541 245 dns_pcb = udp_new();
Michael J. Spencer 1:f5ac63519541 246
Michael J. Spencer 1:f5ac63519541 247 if (dns_pcb != NULL) {
Michael J. Spencer 1:f5ac63519541 248 /* initialize DNS table not needed (initialized to zero since it is a
Michael J. Spencer 1:f5ac63519541 249 * global variable) */
Michael J. Spencer 1:f5ac63519541 250 LWIP_ASSERT("For implicit initialization to work, DNS_STATE_UNUSED needs to be 0",
Michael J. Spencer 1:f5ac63519541 251 DNS_STATE_UNUSED == 0);
Michael J. Spencer 1:f5ac63519541 252
Michael J. Spencer 1:f5ac63519541 253 /* initialize DNS client */
Michael J. Spencer 1:f5ac63519541 254 udp_bind(dns_pcb, IP_ADDR_ANY, 0);
Michael J. Spencer 1:f5ac63519541 255 udp_recv(dns_pcb, dns_recv, NULL);
Michael J. Spencer 1:f5ac63519541 256
Michael J. Spencer 1:f5ac63519541 257 /* initialize default DNS primary server */
Michael J. Spencer 1:f5ac63519541 258 dns_setserver(0, &dnsserver);
Michael J. Spencer 1:f5ac63519541 259 }
Michael J. Spencer 1:f5ac63519541 260 }
Michael J. Spencer 1:f5ac63519541 261 #if DNS_LOCAL_HOSTLIST
Michael J. Spencer 1:f5ac63519541 262 dns_init_local();
Michael J. Spencer 1:f5ac63519541 263 #endif
Michael J. Spencer 1:f5ac63519541 264 }
Michael J. Spencer 1:f5ac63519541 265
Michael J. Spencer 1:f5ac63519541 266 /**
Michael J. Spencer 1:f5ac63519541 267 * Initialize one of the DNS servers.
Michael J. Spencer 1:f5ac63519541 268 *
Michael J. Spencer 1:f5ac63519541 269 * @param numdns the index of the DNS server to set must be < DNS_MAX_SERVERS
Michael J. Spencer 1:f5ac63519541 270 * @param dnsserver IP address of the DNS server to set
Michael J. Spencer 1:f5ac63519541 271 */
Michael J. Spencer 1:f5ac63519541 272 void
Michael J. Spencer 1:f5ac63519541 273 dns_setserver(u8_t numdns, ip_addr_t *dnsserver)
Michael J. Spencer 1:f5ac63519541 274 {
Michael J. Spencer 1:f5ac63519541 275 if ((numdns < DNS_MAX_SERVERS) && (dns_pcb != NULL) &&
Michael J. Spencer 1:f5ac63519541 276 (dnsserver != NULL) && !ip_addr_isany(dnsserver)) {
Michael J. Spencer 1:f5ac63519541 277 dns_servers[numdns] = (*dnsserver);
Michael J. Spencer 1:f5ac63519541 278 }
Michael J. Spencer 1:f5ac63519541 279 }
Michael J. Spencer 1:f5ac63519541 280
Michael J. Spencer 1:f5ac63519541 281 /**
Michael J. Spencer 1:f5ac63519541 282 * Obtain one of the currently configured DNS server.
Michael J. Spencer 1:f5ac63519541 283 *
Michael J. Spencer 1:f5ac63519541 284 * @param numdns the index of the DNS server
Michael J. Spencer 1:f5ac63519541 285 * @return IP address of the indexed DNS server or "ip_addr_any" if the DNS
Michael J. Spencer 1:f5ac63519541 286 * server has not been configured.
Michael J. Spencer 1:f5ac63519541 287 */
Michael J. Spencer 1:f5ac63519541 288 ip_addr_t
Michael J. Spencer 1:f5ac63519541 289 dns_getserver(u8_t numdns)
Michael J. Spencer 1:f5ac63519541 290 {
Michael J. Spencer 1:f5ac63519541 291 if (numdns < DNS_MAX_SERVERS) {
Michael J. Spencer 1:f5ac63519541 292 return dns_servers[numdns];
Michael J. Spencer 1:f5ac63519541 293 } else {
Michael J. Spencer 1:f5ac63519541 294 return *IP_ADDR_ANY;
Michael J. Spencer 1:f5ac63519541 295 }
Michael J. Spencer 1:f5ac63519541 296 }
Michael J. Spencer 1:f5ac63519541 297
Michael J. Spencer 1:f5ac63519541 298 /**
Michael J. Spencer 1:f5ac63519541 299 * The DNS resolver client timer - handle retries and timeouts and should
Michael J. Spencer 1:f5ac63519541 300 * be called every DNS_TMR_INTERVAL milliseconds (every second by default).
Michael J. Spencer 1:f5ac63519541 301 */
Michael J. Spencer 1:f5ac63519541 302 void
Michael J. Spencer 1:f5ac63519541 303 dns_tmr(void)
Michael J. Spencer 1:f5ac63519541 304 {
Michael J. Spencer 1:f5ac63519541 305 if (dns_pcb != NULL) {
Michael J. Spencer 1:f5ac63519541 306 LWIP_DEBUGF(DNS_DEBUG, ("dns_tmr: dns_check_entries\n"));
Michael J. Spencer 1:f5ac63519541 307 dns_check_entries();
Michael J. Spencer 1:f5ac63519541 308 }
Michael J. Spencer 1:f5ac63519541 309 }
Michael J. Spencer 1:f5ac63519541 310
Michael J. Spencer 1:f5ac63519541 311 #if DNS_LOCAL_HOSTLIST
Michael J. Spencer 1:f5ac63519541 312 static void
Michael J. Spencer 1:f5ac63519541 313 dns_init_local()
Michael J. Spencer 1:f5ac63519541 314 {
Michael J. Spencer 1:f5ac63519541 315 #if DNS_LOCAL_HOSTLIST_IS_DYNAMIC && defined(DNS_LOCAL_HOSTLIST_INIT)
Michael J. Spencer 1:f5ac63519541 316 int i;
Michael J. Spencer 1:f5ac63519541 317 struct local_hostlist_entry *entry;
Michael J. Spencer 1:f5ac63519541 318 /* Dynamic: copy entries from DNS_LOCAL_HOSTLIST_INIT to list */
Michael J. Spencer 1:f5ac63519541 319 struct local_hostlist_entry local_hostlist_init[] = DNS_LOCAL_HOSTLIST_INIT;
Michael J. Spencer 1:f5ac63519541 320 size_t namelen;
Michael J. Spencer 1:f5ac63519541 321 for (i = 0; i < sizeof(local_hostlist_init) / sizeof(struct local_hostlist_entry); i++) {
Michael J. Spencer 1:f5ac63519541 322 struct local_hostlist_entry *init_entry = &local_hostlist_init[i];
Michael J. Spencer 1:f5ac63519541 323 LWIP_ASSERT("invalid host name (NULL)", init_entry->name != NULL);
Michael J. Spencer 1:f5ac63519541 324 namelen = strlen(init_entry->name);
Michael J. Spencer 1:f5ac63519541 325 LWIP_ASSERT("namelen <= DNS_LOCAL_HOSTLIST_MAX_NAMELEN", namelen <= DNS_LOCAL_HOSTLIST_MAX_NAMELEN);
Michael J. Spencer 1:f5ac63519541 326 entry = (struct local_hostlist_entry *)memp_malloc(MEMP_LOCALHOSTLIST);
Michael J. Spencer 1:f5ac63519541 327 LWIP_ASSERT("mem-error in dns_init_local", entry != NULL);
Michael J. Spencer 1:f5ac63519541 328 if (entry != NULL) {
Michael J. Spencer 1:f5ac63519541 329 entry->name = (char*)entry + sizeof(struct local_hostlist_entry);
Michael J. Spencer 1:f5ac63519541 330 MEMCPY((char*)entry->name, init_entry->name, namelen);
Michael J. Spencer 1:f5ac63519541 331 ((char*)entry->name)[namelen] = 0;
Michael J. Spencer 1:f5ac63519541 332 entry->addr = init_entry->addr;
Michael J. Spencer 1:f5ac63519541 333 entry->next = local_hostlist_dynamic;
Michael J. Spencer 1:f5ac63519541 334 local_hostlist_dynamic = entry;
Michael J. Spencer 1:f5ac63519541 335 }
Michael J. Spencer 1:f5ac63519541 336 }
Michael J. Spencer 1:f5ac63519541 337 #endif /* DNS_LOCAL_HOSTLIST_IS_DYNAMIC && defined(DNS_LOCAL_HOSTLIST_INIT) */
Michael J. Spencer 1:f5ac63519541 338 }
Michael J. Spencer 1:f5ac63519541 339
Michael J. Spencer 1:f5ac63519541 340 /**
Michael J. Spencer 1:f5ac63519541 341 * Scans the local host-list for a hostname.
Michael J. Spencer 1:f5ac63519541 342 *
Michael J. Spencer 1:f5ac63519541 343 * @param hostname Hostname to look for in the local host-list
Michael J. Spencer 1:f5ac63519541 344 * @return The first IP address for the hostname in the local host-list or
Michael J. Spencer 1:f5ac63519541 345 * IPADDR_NONE if not found.
Michael J. Spencer 1:f5ac63519541 346 */
Michael J. Spencer 1:f5ac63519541 347 static u32_t
Michael J. Spencer 1:f5ac63519541 348 dns_lookup_local(const char *hostname)
Michael J. Spencer 1:f5ac63519541 349 {
Michael J. Spencer 1:f5ac63519541 350 #if DNS_LOCAL_HOSTLIST_IS_DYNAMIC
Michael J. Spencer 1:f5ac63519541 351 struct local_hostlist_entry *entry = local_hostlist_dynamic;
Michael J. Spencer 1:f5ac63519541 352 while(entry != NULL) {
Michael J. Spencer 1:f5ac63519541 353 if(strcmp(entry->name, hostname) == 0) {
Michael J. Spencer 1:f5ac63519541 354 return ip4_addr_get_u32(&entry->addr);
Michael J. Spencer 1:f5ac63519541 355 }
Michael J. Spencer 1:f5ac63519541 356 entry = entry->next;
Michael J. Spencer 1:f5ac63519541 357 }
Michael J. Spencer 1:f5ac63519541 358 #else /* DNS_LOCAL_HOSTLIST_IS_DYNAMIC */
Michael J. Spencer 1:f5ac63519541 359 int i;
Michael J. Spencer 1:f5ac63519541 360 for (i = 0; i < sizeof(local_hostlist_static) / sizeof(struct local_hostlist_entry); i++) {
Michael J. Spencer 1:f5ac63519541 361 if(strcmp(local_hostlist_static[i].name, hostname) == 0) {
Michael J. Spencer 1:f5ac63519541 362 return ip4_addr_get_u32(&local_hostlist_static[i].addr);
Michael J. Spencer 1:f5ac63519541 363 }
Michael J. Spencer 1:f5ac63519541 364 }
Michael J. Spencer 1:f5ac63519541 365 #endif /* DNS_LOCAL_HOSTLIST_IS_DYNAMIC */
Michael J. Spencer 1:f5ac63519541 366 return IPADDR_NONE;
Michael J. Spencer 1:f5ac63519541 367 }
Michael J. Spencer 1:f5ac63519541 368
Michael J. Spencer 1:f5ac63519541 369 #if DNS_LOCAL_HOSTLIST_IS_DYNAMIC
Michael J. Spencer 1:f5ac63519541 370 /** Remove all entries from the local host-list for a specific hostname
Michael J. Spencer 1:f5ac63519541 371 * and/or IP addess
Michael J. Spencer 1:f5ac63519541 372 *
Michael J. Spencer 1:f5ac63519541 373 * @param hostname hostname for which entries shall be removed from the local
Michael J. Spencer 1:f5ac63519541 374 * host-list
Michael J. Spencer 1:f5ac63519541 375 * @param addr address for which entries shall be removed from the local host-list
Michael J. Spencer 1:f5ac63519541 376 * @return the number of removed entries
Michael J. Spencer 1:f5ac63519541 377 */
Michael J. Spencer 1:f5ac63519541 378 int
Michael J. Spencer 1:f5ac63519541 379 dns_local_removehost(const char *hostname, const ip_addr_t *addr)
Michael J. Spencer 1:f5ac63519541 380 {
Michael J. Spencer 1:f5ac63519541 381 int removed = 0;
Michael J. Spencer 1:f5ac63519541 382 struct local_hostlist_entry *entry = local_hostlist_dynamic;
Michael J. Spencer 1:f5ac63519541 383 struct local_hostlist_entry *last_entry = NULL;
Michael J. Spencer 1:f5ac63519541 384 while (entry != NULL) {
Michael J. Spencer 1:f5ac63519541 385 if (((hostname == NULL) || !strcmp(entry->name, hostname)) &&
Michael J. Spencer 1:f5ac63519541 386 ((addr == NULL) || ip_addr_cmp(&entry->addr, addr))) {
Michael J. Spencer 1:f5ac63519541 387 struct local_hostlist_entry *free_entry;
Michael J. Spencer 1:f5ac63519541 388 if (last_entry != NULL) {
Michael J. Spencer 1:f5ac63519541 389 last_entry->next = entry->next;
Michael J. Spencer 1:f5ac63519541 390 } else {
Michael J. Spencer 1:f5ac63519541 391 local_hostlist_dynamic = entry->next;
Michael J. Spencer 1:f5ac63519541 392 }
Michael J. Spencer 1:f5ac63519541 393 free_entry = entry;
Michael J. Spencer 1:f5ac63519541 394 entry = entry->next;
Michael J. Spencer 1:f5ac63519541 395 memp_free(MEMP_LOCALHOSTLIST, free_entry);
Michael J. Spencer 1:f5ac63519541 396 removed++;
Michael J. Spencer 1:f5ac63519541 397 } else {
Michael J. Spencer 1:f5ac63519541 398 last_entry = entry;
Michael J. Spencer 1:f5ac63519541 399 entry = entry->next;
Michael J. Spencer 1:f5ac63519541 400 }
Michael J. Spencer 1:f5ac63519541 401 }
Michael J. Spencer 1:f5ac63519541 402 return removed;
Michael J. Spencer 1:f5ac63519541 403 }
Michael J. Spencer 1:f5ac63519541 404
Michael J. Spencer 1:f5ac63519541 405 /**
Michael J. Spencer 1:f5ac63519541 406 * Add a hostname/IP address pair to the local host-list.
Michael J. Spencer 1:f5ac63519541 407 * Duplicates are not checked.
Michael J. Spencer 1:f5ac63519541 408 *
Michael J. Spencer 1:f5ac63519541 409 * @param hostname hostname of the new entry
Michael J. Spencer 1:f5ac63519541 410 * @param addr IP address of the new entry
Michael J. Spencer 1:f5ac63519541 411 * @return ERR_OK if succeeded or ERR_MEM on memory error
Michael J. Spencer 1:f5ac63519541 412 */
Michael J. Spencer 1:f5ac63519541 413 err_t
Michael J. Spencer 1:f5ac63519541 414 dns_local_addhost(const char *hostname, const ip_addr_t *addr)
Michael J. Spencer 1:f5ac63519541 415 {
Michael J. Spencer 1:f5ac63519541 416 struct local_hostlist_entry *entry;
Michael J. Spencer 1:f5ac63519541 417 size_t namelen;
Michael J. Spencer 1:f5ac63519541 418 LWIP_ASSERT("invalid host name (NULL)", hostname != NULL);
Michael J. Spencer 1:f5ac63519541 419 namelen = strlen(hostname);
Michael J. Spencer 1:f5ac63519541 420 LWIP_ASSERT("namelen <= DNS_LOCAL_HOSTLIST_MAX_NAMELEN", namelen <= DNS_LOCAL_HOSTLIST_MAX_NAMELEN);
Michael J. Spencer 1:f5ac63519541 421 entry = (struct local_hostlist_entry *)memp_malloc(MEMP_LOCALHOSTLIST);
Michael J. Spencer 1:f5ac63519541 422 if (entry == NULL) {
Michael J. Spencer 1:f5ac63519541 423 return ERR_MEM;
Michael J. Spencer 1:f5ac63519541 424 }
Michael J. Spencer 1:f5ac63519541 425 entry->name = (char*)entry + sizeof(struct local_hostlist_entry);
Michael J. Spencer 1:f5ac63519541 426 MEMCPY((char*)entry->name, hostname, namelen);
Michael J. Spencer 1:f5ac63519541 427 ((char*)entry->name)[namelen] = 0;
Michael J. Spencer 1:f5ac63519541 428 ip_addr_copy(entry->addr, *addr);
Michael J. Spencer 1:f5ac63519541 429 entry->next = local_hostlist_dynamic;
Michael J. Spencer 1:f5ac63519541 430 local_hostlist_dynamic = entry;
Michael J. Spencer 1:f5ac63519541 431 return ERR_OK;
Michael J. Spencer 1:f5ac63519541 432 }
Michael J. Spencer 1:f5ac63519541 433 #endif /* DNS_LOCAL_HOSTLIST_IS_DYNAMIC*/
Michael J. Spencer 1:f5ac63519541 434 #endif /* DNS_LOCAL_HOSTLIST */
Michael J. Spencer 1:f5ac63519541 435
Michael J. Spencer 1:f5ac63519541 436 /**
Michael J. Spencer 1:f5ac63519541 437 * Look up a hostname in the array of known hostnames.
Michael J. Spencer 1:f5ac63519541 438 *
Michael J. Spencer 1:f5ac63519541 439 * @note This function only looks in the internal array of known
Michael J. Spencer 1:f5ac63519541 440 * hostnames, it does not send out a query for the hostname if none
Michael J. Spencer 1:f5ac63519541 441 * was found. The function dns_enqueue() can be used to send a query
Michael J. Spencer 1:f5ac63519541 442 * for a hostname.
Michael J. Spencer 1:f5ac63519541 443 *
Michael J. Spencer 1:f5ac63519541 444 * @param name the hostname to look up
Michael J. Spencer 1:f5ac63519541 445 * @return the hostname's IP address, as u32_t (instead of ip_addr_t to
Michael J. Spencer 1:f5ac63519541 446 * better check for failure: != IPADDR_NONE) or IPADDR_NONE if the hostname
Michael J. Spencer 1:f5ac63519541 447 * was not found in the cached dns_table.
Michael J. Spencer 1:f5ac63519541 448 */
Michael J. Spencer 1:f5ac63519541 449 static u32_t
Michael J. Spencer 1:f5ac63519541 450 dns_lookup(const char *name)
Michael J. Spencer 1:f5ac63519541 451 {
Michael J. Spencer 1:f5ac63519541 452 u8_t i;
Michael J. Spencer 1:f5ac63519541 453 #if DNS_LOCAL_HOSTLIST || defined(DNS_LOOKUP_LOCAL_EXTERN)
Michael J. Spencer 1:f5ac63519541 454 u32_t addr;
Michael J. Spencer 1:f5ac63519541 455 #endif /* DNS_LOCAL_HOSTLIST || defined(DNS_LOOKUP_LOCAL_EXTERN) */
Michael J. Spencer 1:f5ac63519541 456 #if DNS_LOCAL_HOSTLIST
Michael J. Spencer 1:f5ac63519541 457 if ((addr = dns_lookup_local(name)) != IPADDR_NONE) {
Michael J. Spencer 1:f5ac63519541 458 return addr;
Michael J. Spencer 1:f5ac63519541 459 }
Michael J. Spencer 1:f5ac63519541 460 #endif /* DNS_LOCAL_HOSTLIST */
Michael J. Spencer 1:f5ac63519541 461 #ifdef DNS_LOOKUP_LOCAL_EXTERN
Michael J. Spencer 1:f5ac63519541 462 if((addr = DNS_LOOKUP_LOCAL_EXTERN(name)) != IPADDR_NONE) {
Michael J. Spencer 1:f5ac63519541 463 return addr;
Michael J. Spencer 1:f5ac63519541 464 }
Michael J. Spencer 1:f5ac63519541 465 #endif /* DNS_LOOKUP_LOCAL_EXTERN */
Michael J. Spencer 1:f5ac63519541 466
Michael J. Spencer 1:f5ac63519541 467 /* Walk through name list, return entry if found. If not, return NULL. */
Michael J. Spencer 1:f5ac63519541 468 for (i = 0; i < DNS_TABLE_SIZE; ++i) {
Michael J. Spencer 1:f5ac63519541 469 if ((dns_table[i].state == DNS_STATE_DONE) &&
Michael J. Spencer 1:f5ac63519541 470 (strcmp(name, dns_table[i].name) == 0)) {
Michael J. Spencer 1:f5ac63519541 471 LWIP_DEBUGF(DNS_DEBUG, ("dns_lookup: \"%s\": found = ", name));
Michael J. Spencer 1:f5ac63519541 472 ip_addr_debug_print(DNS_DEBUG, &(dns_table[i].ipaddr));
Michael J. Spencer 1:f5ac63519541 473 LWIP_DEBUGF(DNS_DEBUG, ("\n"));
Michael J. Spencer 1:f5ac63519541 474 return ip4_addr_get_u32(&dns_table[i].ipaddr);
Michael J. Spencer 1:f5ac63519541 475 }
Michael J. Spencer 1:f5ac63519541 476 }
Michael J. Spencer 1:f5ac63519541 477
Michael J. Spencer 1:f5ac63519541 478 return IPADDR_NONE;
Michael J. Spencer 1:f5ac63519541 479 }
Michael J. Spencer 1:f5ac63519541 480
Michael J. Spencer 1:f5ac63519541 481 #if DNS_DOES_NAME_CHECK
Michael J. Spencer 1:f5ac63519541 482 /**
Michael J. Spencer 1:f5ac63519541 483 * Compare the "dotted" name "query" with the encoded name "response"
Michael J. Spencer 1:f5ac63519541 484 * to make sure an answer from the DNS server matches the current dns_table
Michael J. Spencer 1:f5ac63519541 485 * entry (otherwise, answers might arrive late for hostname not on the list
Michael J. Spencer 1:f5ac63519541 486 * any more).
Michael J. Spencer 1:f5ac63519541 487 *
Michael J. Spencer 1:f5ac63519541 488 * @param query hostname (not encoded) from the dns_table
Michael J. Spencer 1:f5ac63519541 489 * @param response encoded hostname in the DNS response
Michael J. Spencer 1:f5ac63519541 490 * @return 0: names equal; 1: names differ
Michael J. Spencer 1:f5ac63519541 491 */
Michael J. Spencer 1:f5ac63519541 492 static u8_t
Michael J. Spencer 1:f5ac63519541 493 dns_compare_name(unsigned char *query, unsigned char *response)
Michael J. Spencer 1:f5ac63519541 494 {
Michael J. Spencer 1:f5ac63519541 495 unsigned char n;
Michael J. Spencer 1:f5ac63519541 496
Michael J. Spencer 1:f5ac63519541 497 do {
Michael J. Spencer 1:f5ac63519541 498 n = *response++;
Michael J. Spencer 1:f5ac63519541 499 /** @see RFC 1035 - 4.1.4. Message compression */
Michael J. Spencer 1:f5ac63519541 500 if ((n & 0xc0) == 0xc0) {
Michael J. Spencer 1:f5ac63519541 501 /* Compressed name */
Michael J. Spencer 1:f5ac63519541 502 break;
Michael J. Spencer 1:f5ac63519541 503 } else {
Michael J. Spencer 1:f5ac63519541 504 /* Not compressed name */
Michael J. Spencer 1:f5ac63519541 505 while (n > 0) {
Michael J. Spencer 1:f5ac63519541 506 if ((*query) != (*response)) {
Michael J. Spencer 1:f5ac63519541 507 return 1;
Michael J. Spencer 1:f5ac63519541 508 }
Michael J. Spencer 1:f5ac63519541 509 ++response;
Michael J. Spencer 1:f5ac63519541 510 ++query;
Michael J. Spencer 1:f5ac63519541 511 --n;
Michael J. Spencer 1:f5ac63519541 512 };
Michael J. Spencer 1:f5ac63519541 513 ++query;
Michael J. Spencer 1:f5ac63519541 514 }
Michael J. Spencer 1:f5ac63519541 515 } while (*response != 0);
Michael J. Spencer 1:f5ac63519541 516
Michael J. Spencer 1:f5ac63519541 517 return 0;
Michael J. Spencer 1:f5ac63519541 518 }
Michael J. Spencer 1:f5ac63519541 519 #endif /* DNS_DOES_NAME_CHECK */
Michael J. Spencer 1:f5ac63519541 520
Michael J. Spencer 1:f5ac63519541 521 /**
Michael J. Spencer 1:f5ac63519541 522 * Walk through a compact encoded DNS name and return the end of the name.
Michael J. Spencer 1:f5ac63519541 523 *
Michael J. Spencer 1:f5ac63519541 524 * @param query encoded DNS name in the DNS server response
Michael J. Spencer 1:f5ac63519541 525 * @return end of the name
Michael J. Spencer 1:f5ac63519541 526 */
Michael J. Spencer 1:f5ac63519541 527 static unsigned char *
Michael J. Spencer 1:f5ac63519541 528 dns_parse_name(unsigned char *query)
Michael J. Spencer 1:f5ac63519541 529 {
Michael J. Spencer 1:f5ac63519541 530 unsigned char n;
Michael J. Spencer 1:f5ac63519541 531
Michael J. Spencer 1:f5ac63519541 532 do {
Michael J. Spencer 1:f5ac63519541 533 n = *query++;
Michael J. Spencer 1:f5ac63519541 534 /** @see RFC 1035 - 4.1.4. Message compression */
Michael J. Spencer 1:f5ac63519541 535 if ((n & 0xc0) == 0xc0) {
Michael J. Spencer 1:f5ac63519541 536 /* Compressed name */
Michael J. Spencer 1:f5ac63519541 537 break;
Michael J. Spencer 1:f5ac63519541 538 } else {
Michael J. Spencer 1:f5ac63519541 539 /* Not compressed name */
Michael J. Spencer 1:f5ac63519541 540 while (n > 0) {
Michael J. Spencer 1:f5ac63519541 541 ++query;
Michael J. Spencer 1:f5ac63519541 542 --n;
Michael J. Spencer 1:f5ac63519541 543 };
Michael J. Spencer 1:f5ac63519541 544 }
Michael J. Spencer 1:f5ac63519541 545 } while (*query != 0);
Michael J. Spencer 1:f5ac63519541 546
Michael J. Spencer 1:f5ac63519541 547 return query + 1;
Michael J. Spencer 1:f5ac63519541 548 }
Michael J. Spencer 1:f5ac63519541 549
Michael J. Spencer 1:f5ac63519541 550 /**
Michael J. Spencer 1:f5ac63519541 551 * Send a DNS query packet.
Michael J. Spencer 1:f5ac63519541 552 *
Michael J. Spencer 1:f5ac63519541 553 * @param numdns index of the DNS server in the dns_servers table
Michael J. Spencer 1:f5ac63519541 554 * @param name hostname to query
Michael J. Spencer 1:f5ac63519541 555 * @param id index of the hostname in dns_table, used as transaction ID in the
Michael J. Spencer 1:f5ac63519541 556 * DNS query packet
Michael J. Spencer 1:f5ac63519541 557 * @return ERR_OK if packet is sent; an err_t indicating the problem otherwise
Michael J. Spencer 1:f5ac63519541 558 */
Michael J. Spencer 1:f5ac63519541 559 static err_t
Michael J. Spencer 1:f5ac63519541 560 dns_send(u8_t numdns, const char* name, u8_t id)
Michael J. Spencer 1:f5ac63519541 561 {
Michael J. Spencer 1:f5ac63519541 562 err_t err;
Michael J. Spencer 1:f5ac63519541 563 struct dns_hdr *hdr;
Michael J. Spencer 1:f5ac63519541 564 struct dns_query qry;
Michael J. Spencer 1:f5ac63519541 565 struct pbuf *p;
Michael J. Spencer 1:f5ac63519541 566 char *query, *nptr;
Michael J. Spencer 1:f5ac63519541 567 const char *pHostname;
Michael J. Spencer 1:f5ac63519541 568 u8_t n;
Michael J. Spencer 1:f5ac63519541 569
Michael J. Spencer 1:f5ac63519541 570 LWIP_DEBUGF(DNS_DEBUG, ("dns_send: dns_servers[%"U16_F"] \"%s\": request\n",
Michael J. Spencer 1:f5ac63519541 571 (u16_t)(numdns), name));
Michael J. Spencer 1:f5ac63519541 572 LWIP_ASSERT("dns server out of array", numdns < DNS_MAX_SERVERS);
Michael J. Spencer 1:f5ac63519541 573 LWIP_ASSERT("dns server has no IP address set", !ip_addr_isany(&dns_servers[numdns]));
Michael J. Spencer 1:f5ac63519541 574
Michael J. Spencer 1:f5ac63519541 575 /* if here, we have either a new query or a retry on a previous query to process */
Michael J. Spencer 1:f5ac63519541 576 p = pbuf_alloc(PBUF_TRANSPORT, SIZEOF_DNS_HDR + DNS_MAX_NAME_LENGTH +
Michael J. Spencer 1:f5ac63519541 577 SIZEOF_DNS_QUERY, PBUF_RAM);
Michael J. Spencer 1:f5ac63519541 578 if (p != NULL) {
Michael J. Spencer 1:f5ac63519541 579 LWIP_ASSERT("pbuf must be in one piece", p->next == NULL);
Michael J. Spencer 1:f5ac63519541 580 /* fill dns header */
Michael J. Spencer 1:f5ac63519541 581 hdr = (struct dns_hdr*)p->payload;
Michael J. Spencer 1:f5ac63519541 582 memset(hdr, 0, SIZEOF_DNS_HDR);
Michael J. Spencer 1:f5ac63519541 583 hdr->id = htons(id);
Michael J. Spencer 1:f5ac63519541 584 hdr->flags1 = DNS_FLAG1_RD;
Michael J. Spencer 1:f5ac63519541 585 hdr->numquestions = PP_HTONS(1);
Michael J. Spencer 1:f5ac63519541 586 query = (char*)hdr + SIZEOF_DNS_HDR;
Michael J. Spencer 1:f5ac63519541 587 pHostname = name;
Michael J. Spencer 1:f5ac63519541 588 --pHostname;
Michael J. Spencer 1:f5ac63519541 589
Michael J. Spencer 1:f5ac63519541 590 /* convert hostname into suitable query format. */
Michael J. Spencer 1:f5ac63519541 591 do {
Michael J. Spencer 1:f5ac63519541 592 ++pHostname;
Michael J. Spencer 1:f5ac63519541 593 nptr = query;
Michael J. Spencer 1:f5ac63519541 594 ++query;
Michael J. Spencer 1:f5ac63519541 595 for(n = 0; *pHostname != '.' && *pHostname != 0; ++pHostname) {
Michael J. Spencer 1:f5ac63519541 596 *query = *pHostname;
Michael J. Spencer 1:f5ac63519541 597 ++query;
Michael J. Spencer 1:f5ac63519541 598 ++n;
Michael J. Spencer 1:f5ac63519541 599 }
Michael J. Spencer 1:f5ac63519541 600 *nptr = n;
Michael J. Spencer 1:f5ac63519541 601 } while(*pHostname != 0);
Michael J. Spencer 1:f5ac63519541 602 *query++='\0';
Michael J. Spencer 1:f5ac63519541 603
Michael J. Spencer 1:f5ac63519541 604 /* fill dns query */
Michael J. Spencer 1:f5ac63519541 605 qry.type = PP_HTONS(DNS_RRTYPE_A);
Michael J. Spencer 1:f5ac63519541 606 qry.cls = PP_HTONS(DNS_RRCLASS_IN);
Michael J. Spencer 1:f5ac63519541 607 SMEMCPY(query, &qry, SIZEOF_DNS_QUERY);
Michael J. Spencer 1:f5ac63519541 608
Michael J. Spencer 1:f5ac63519541 609 /* resize pbuf to the exact dns query */
Michael J. Spencer 1:f5ac63519541 610 pbuf_realloc(p, (u16_t)((query + SIZEOF_DNS_QUERY) - ((char*)(p->payload))));
Michael J. Spencer 1:f5ac63519541 611
Michael J. Spencer 1:f5ac63519541 612 /* connect to the server for faster receiving */
Michael J. Spencer 1:f5ac63519541 613 udp_connect(dns_pcb, &dns_servers[numdns], DNS_SERVER_PORT);
Michael J. Spencer 1:f5ac63519541 614 /* send dns packet */
Michael J. Spencer 1:f5ac63519541 615 err = udp_sendto(dns_pcb, p, &dns_servers[numdns], DNS_SERVER_PORT);
Michael J. Spencer 1:f5ac63519541 616
Michael J. Spencer 1:f5ac63519541 617 /* free pbuf */
Michael J. Spencer 1:f5ac63519541 618 pbuf_free(p);
Michael J. Spencer 1:f5ac63519541 619 } else {
Michael J. Spencer 1:f5ac63519541 620 err = ERR_MEM;
Michael J. Spencer 1:f5ac63519541 621 }
Michael J. Spencer 1:f5ac63519541 622
Michael J. Spencer 1:f5ac63519541 623 return err;
Michael J. Spencer 1:f5ac63519541 624 }
Michael J. Spencer 1:f5ac63519541 625
Michael J. Spencer 1:f5ac63519541 626 /**
Michael J. Spencer 1:f5ac63519541 627 * dns_check_entry() - see if pEntry has not yet been queried and, if so, sends out a query.
Michael J. Spencer 1:f5ac63519541 628 * Check an entry in the dns_table:
Michael J. Spencer 1:f5ac63519541 629 * - send out query for new entries
Michael J. Spencer 1:f5ac63519541 630 * - retry old pending entries on timeout (also with different servers)
Michael J. Spencer 1:f5ac63519541 631 * - remove completed entries from the table if their TTL has expired
Michael J. Spencer 1:f5ac63519541 632 *
Michael J. Spencer 1:f5ac63519541 633 * @param i index of the dns_table entry to check
Michael J. Spencer 1:f5ac63519541 634 */
Michael J. Spencer 1:f5ac63519541 635 static void
Michael J. Spencer 1:f5ac63519541 636 dns_check_entry(u8_t i)
Michael J. Spencer 1:f5ac63519541 637 {
Michael J. Spencer 1:f5ac63519541 638 err_t err;
Michael J. Spencer 1:f5ac63519541 639 struct dns_table_entry *pEntry = &dns_table[i];
Michael J. Spencer 1:f5ac63519541 640
Michael J. Spencer 1:f5ac63519541 641 LWIP_ASSERT("array index out of bounds", i < DNS_TABLE_SIZE);
Michael J. Spencer 1:f5ac63519541 642
Michael J. Spencer 1:f5ac63519541 643 switch(pEntry->state) {
Michael J. Spencer 1:f5ac63519541 644
Michael J. Spencer 1:f5ac63519541 645 case DNS_STATE_NEW: {
Michael J. Spencer 1:f5ac63519541 646 /* initialize new entry */
Michael J. Spencer 1:f5ac63519541 647 pEntry->state = DNS_STATE_ASKING;
Michael J. Spencer 1:f5ac63519541 648 pEntry->numdns = 0;
Michael J. Spencer 1:f5ac63519541 649 pEntry->tmr = 1;
Michael J. Spencer 1:f5ac63519541 650 pEntry->retries = 0;
Michael J. Spencer 1:f5ac63519541 651
Michael J. Spencer 1:f5ac63519541 652 /* send DNS packet for this entry */
Michael J. Spencer 1:f5ac63519541 653 err = dns_send(pEntry->numdns, pEntry->name, i);
Michael J. Spencer 1:f5ac63519541 654 if (err != ERR_OK) {
Michael J. Spencer 1:f5ac63519541 655 LWIP_DEBUGF(DNS_DEBUG | LWIP_DBG_LEVEL_WARNING,
Michael J. Spencer 1:f5ac63519541 656 ("dns_send returned error: %d\n", err)); //FIX DG, lwip_strerr is part of lwip/api
Michael J. Spencer 1:f5ac63519541 657 }
Michael J. Spencer 1:f5ac63519541 658 break;
Michael J. Spencer 1:f5ac63519541 659 }
Michael J. Spencer 1:f5ac63519541 660
Michael J. Spencer 1:f5ac63519541 661 case DNS_STATE_ASKING: {
Michael J. Spencer 1:f5ac63519541 662 if (--pEntry->tmr == 0) {
Michael J. Spencer 1:f5ac63519541 663 if (++pEntry->retries == DNS_MAX_RETRIES) {
Michael J. Spencer 1:f5ac63519541 664 if ((pEntry->numdns+1<DNS_MAX_SERVERS) && !ip_addr_isany(&dns_servers[pEntry->numdns+1])) {
Michael J. Spencer 1:f5ac63519541 665 /* change of server */
Michael J. Spencer 1:f5ac63519541 666 pEntry->numdns++;
Michael J. Spencer 1:f5ac63519541 667 pEntry->tmr = 1;
Michael J. Spencer 1:f5ac63519541 668 pEntry->retries = 0;
Michael J. Spencer 1:f5ac63519541 669 break;
Michael J. Spencer 1:f5ac63519541 670 } else {
Michael J. Spencer 1:f5ac63519541 671 LWIP_DEBUGF(DNS_DEBUG, ("dns_check_entry: \"%s\": timeout\n", pEntry->name));
Michael J. Spencer 1:f5ac63519541 672 /* call specified callback function if provided */
Michael J. Spencer 1:f5ac63519541 673 if (pEntry->found)
Michael J. Spencer 1:f5ac63519541 674 (*pEntry->found)(pEntry->name, NULL, pEntry->arg);
Michael J. Spencer 1:f5ac63519541 675 /* flush this entry */
Michael J. Spencer 1:f5ac63519541 676 pEntry->state = DNS_STATE_UNUSED;
Michael J. Spencer 1:f5ac63519541 677 pEntry->found = NULL;
Michael J. Spencer 1:f5ac63519541 678 break;
Michael J. Spencer 1:f5ac63519541 679 }
Michael J. Spencer 1:f5ac63519541 680 }
Michael J. Spencer 1:f5ac63519541 681
Michael J. Spencer 1:f5ac63519541 682 /* wait longer for the next retry */
Michael J. Spencer 1:f5ac63519541 683 pEntry->tmr = pEntry->retries;
Michael J. Spencer 1:f5ac63519541 684
Michael J. Spencer 1:f5ac63519541 685 /* send DNS packet for this entry */
Michael J. Spencer 1:f5ac63519541 686 err = dns_send(pEntry->numdns, pEntry->name, i);
Michael J. Spencer 1:f5ac63519541 687 if (err != ERR_OK) {
Michael J. Spencer 1:f5ac63519541 688 LWIP_DEBUGF(DNS_DEBUG | LWIP_DBG_LEVEL_WARNING,
Michael J. Spencer 1:f5ac63519541 689 ("dns_send returned error: %d\n", err)); //FIX DG, lwip_strerr is part of lwip/api
Michael J. Spencer 1:f5ac63519541 690 }
Michael J. Spencer 1:f5ac63519541 691 }
Michael J. Spencer 1:f5ac63519541 692 break;
Michael J. Spencer 1:f5ac63519541 693 }
Michael J. Spencer 1:f5ac63519541 694
Michael J. Spencer 1:f5ac63519541 695 case DNS_STATE_DONE: {
Michael J. Spencer 1:f5ac63519541 696 /* if the time to live is nul */
Michael J. Spencer 1:f5ac63519541 697 if (--pEntry->ttl == 0) {
Michael J. Spencer 1:f5ac63519541 698 LWIP_DEBUGF(DNS_DEBUG, ("dns_check_entry: \"%s\": flush\n", pEntry->name));
Michael J. Spencer 1:f5ac63519541 699 /* flush this entry */
Michael J. Spencer 1:f5ac63519541 700 pEntry->state = DNS_STATE_UNUSED;
Michael J. Spencer 1:f5ac63519541 701 pEntry->found = NULL;
Michael J. Spencer 1:f5ac63519541 702 }
Michael J. Spencer 1:f5ac63519541 703 break;
Michael J. Spencer 1:f5ac63519541 704 }
Michael J. Spencer 1:f5ac63519541 705 case DNS_STATE_UNUSED:
Michael J. Spencer 1:f5ac63519541 706 /* nothing to do */
Michael J. Spencer 1:f5ac63519541 707 break;
Michael J. Spencer 1:f5ac63519541 708 default:
Michael J. Spencer 1:f5ac63519541 709 LWIP_ASSERT("unknown dns_table entry state:", 0);
Michael J. Spencer 1:f5ac63519541 710 break;
Michael J. Spencer 1:f5ac63519541 711 }
Michael J. Spencer 1:f5ac63519541 712 }
Michael J. Spencer 1:f5ac63519541 713
Michael J. Spencer 1:f5ac63519541 714 /**
Michael J. Spencer 1:f5ac63519541 715 * Call dns_check_entry for each entry in dns_table - check all entries.
Michael J. Spencer 1:f5ac63519541 716 */
Michael J. Spencer 1:f5ac63519541 717 static void
Michael J. Spencer 1:f5ac63519541 718 dns_check_entries(void)
Michael J. Spencer 1:f5ac63519541 719 {
Michael J. Spencer 1:f5ac63519541 720 u8_t i;
Michael J. Spencer 1:f5ac63519541 721
Michael J. Spencer 1:f5ac63519541 722 for (i = 0; i < DNS_TABLE_SIZE; ++i) {
Michael J. Spencer 1:f5ac63519541 723 dns_check_entry(i);
Michael J. Spencer 1:f5ac63519541 724 }
Michael J. Spencer 1:f5ac63519541 725 }
Michael J. Spencer 1:f5ac63519541 726
Michael J. Spencer 1:f5ac63519541 727 /**
Michael J. Spencer 1:f5ac63519541 728 * Receive input function for DNS response packets arriving for the dns UDP pcb.
Michael J. Spencer 1:f5ac63519541 729 *
Michael J. Spencer 1:f5ac63519541 730 * @params see udp.h
Michael J. Spencer 1:f5ac63519541 731 */
Michael J. Spencer 1:f5ac63519541 732 static void
Michael J. Spencer 1:f5ac63519541 733 dns_recv(void *arg, struct udp_pcb *pcb, struct pbuf *p, ip_addr_t *addr, u16_t port)
Michael J. Spencer 1:f5ac63519541 734 {
Michael J. Spencer 1:f5ac63519541 735 u16_t i;
Michael J. Spencer 1:f5ac63519541 736 char *pHostname;
Michael J. Spencer 1:f5ac63519541 737 struct dns_hdr *hdr;
Michael J. Spencer 1:f5ac63519541 738 struct dns_answer ans;
Michael J. Spencer 1:f5ac63519541 739 struct dns_table_entry *pEntry;
Michael J. Spencer 1:f5ac63519541 740 u16_t nquestions, nanswers;
Michael J. Spencer 1:f5ac63519541 741
Michael J. Spencer 1:f5ac63519541 742 LWIP_UNUSED_ARG(arg);
Michael J. Spencer 1:f5ac63519541 743 LWIP_UNUSED_ARG(pcb);
Michael J. Spencer 1:f5ac63519541 744 LWIP_UNUSED_ARG(addr);
Michael J. Spencer 1:f5ac63519541 745 LWIP_UNUSED_ARG(port);
Michael J. Spencer 1:f5ac63519541 746
Michael J. Spencer 1:f5ac63519541 747 /* is the dns message too big ? */
Michael J. Spencer 1:f5ac63519541 748 if (p->tot_len > DNS_MSG_SIZE) {
Michael J. Spencer 1:f5ac63519541 749 LWIP_DEBUGF(DNS_DEBUG, ("dns_recv: pbuf too big\n"));
Michael J. Spencer 1:f5ac63519541 750 /* free pbuf and return */
Michael J. Spencer 1:f5ac63519541 751 goto memerr;
Michael J. Spencer 1:f5ac63519541 752 }
Michael J. Spencer 1:f5ac63519541 753
Michael J. Spencer 1:f5ac63519541 754 /* is the dns message big enough ? */
Michael J. Spencer 1:f5ac63519541 755 if (p->tot_len < (SIZEOF_DNS_HDR + SIZEOF_DNS_QUERY + SIZEOF_DNS_ANSWER)) {
Michael J. Spencer 1:f5ac63519541 756 LWIP_DEBUGF(DNS_DEBUG, ("dns_recv: pbuf too small\n"));
Michael J. Spencer 1:f5ac63519541 757 /* free pbuf and return */
Michael J. Spencer 1:f5ac63519541 758 goto memerr;
Michael J. Spencer 1:f5ac63519541 759 }
Michael J. Spencer 1:f5ac63519541 760
Michael J. Spencer 1:f5ac63519541 761 /* copy dns payload inside static buffer for processing */
Michael J. Spencer 1:f5ac63519541 762 if (pbuf_copy_partial(p, dns_payload, p->tot_len, 0) == p->tot_len) {
Michael J. Spencer 1:f5ac63519541 763 /* The ID in the DNS header should be our entry into the name table. */
Michael J. Spencer 1:f5ac63519541 764 hdr = (struct dns_hdr*)dns_payload;
Michael J. Spencer 1:f5ac63519541 765 i = htons(hdr->id);
Michael J. Spencer 1:f5ac63519541 766 if (i < DNS_TABLE_SIZE) {
Michael J. Spencer 1:f5ac63519541 767 pEntry = &dns_table[i];
Michael J. Spencer 1:f5ac63519541 768 if(pEntry->state == DNS_STATE_ASKING) {
Michael J. Spencer 1:f5ac63519541 769 /* This entry is now completed. */
Michael J. Spencer 1:f5ac63519541 770 pEntry->state = DNS_STATE_DONE;
Michael J. Spencer 1:f5ac63519541 771 pEntry->err = hdr->flags2 & DNS_FLAG2_ERR_MASK;
Michael J. Spencer 1:f5ac63519541 772
Michael J. Spencer 1:f5ac63519541 773 /* We only care about the question(s) and the answers. The authrr
Michael J. Spencer 1:f5ac63519541 774 and the extrarr are simply discarded. */
Michael J. Spencer 1:f5ac63519541 775 nquestions = htons(hdr->numquestions);
Michael J. Spencer 1:f5ac63519541 776 nanswers = htons(hdr->numanswers);
Michael J. Spencer 1:f5ac63519541 777
Michael J. Spencer 1:f5ac63519541 778 /* Check for error. If so, call callback to inform. */
Michael J. Spencer 1:f5ac63519541 779 if (((hdr->flags1 & DNS_FLAG1_RESPONSE) == 0) || (pEntry->err != 0) || (nquestions != 1)) {
Michael J. Spencer 1:f5ac63519541 780 LWIP_DEBUGF(DNS_DEBUG, ("dns_recv: \"%s\": error in flags\n", pEntry->name));
Michael J. Spencer 1:f5ac63519541 781 /* call callback to indicate error, clean up memory and return */
Michael J. Spencer 1:f5ac63519541 782 goto responseerr;
Michael J. Spencer 1:f5ac63519541 783 }
Michael J. Spencer 1:f5ac63519541 784
Michael J. Spencer 1:f5ac63519541 785 #if DNS_DOES_NAME_CHECK
Michael J. Spencer 1:f5ac63519541 786 /* Check if the name in the "question" part match with the name in the entry. */
Michael J. Spencer 1:f5ac63519541 787 if (dns_compare_name((unsigned char *)(pEntry->name), (unsigned char *)dns_payload + SIZEOF_DNS_HDR) != 0) {
Michael J. Spencer 1:f5ac63519541 788 LWIP_DEBUGF(DNS_DEBUG, ("dns_recv: \"%s\": response not match to query\n", pEntry->name));
Michael J. Spencer 1:f5ac63519541 789 /* call callback to indicate error, clean up memory and return */
Michael J. Spencer 1:f5ac63519541 790 goto responseerr;
Michael J. Spencer 1:f5ac63519541 791 }
Michael J. Spencer 1:f5ac63519541 792 #endif /* DNS_DOES_NAME_CHECK */
Michael J. Spencer 1:f5ac63519541 793
Michael J. Spencer 1:f5ac63519541 794 /* Skip the name in the "question" part */
Michael J. Spencer 1:f5ac63519541 795 pHostname = (char *) dns_parse_name((unsigned char *)dns_payload + SIZEOF_DNS_HDR) + SIZEOF_DNS_QUERY;
Michael J. Spencer 1:f5ac63519541 796
Michael J. Spencer 1:f5ac63519541 797 while (nanswers > 0) {
Michael J. Spencer 1:f5ac63519541 798 /* skip answer resource record's host name */
Michael J. Spencer 1:f5ac63519541 799 pHostname = (char *) dns_parse_name((unsigned char *)pHostname);
Michael J. Spencer 1:f5ac63519541 800
Michael J. Spencer 1:f5ac63519541 801 /* Check for IP address type and Internet class. Others are discarded. */
Michael J. Spencer 1:f5ac63519541 802 SMEMCPY(&ans, pHostname, SIZEOF_DNS_ANSWER);
Michael J. Spencer 1:f5ac63519541 803 if((ans.type == PP_HTONS(DNS_RRTYPE_A)) && (ans.cls == PP_HTONS(DNS_RRCLASS_IN)) &&
Michael J. Spencer 1:f5ac63519541 804 (ans.len == PP_HTONS(sizeof(ip_addr_t))) ) {
Michael J. Spencer 1:f5ac63519541 805 /* read the answer resource record's TTL, and maximize it if needed */
Michael J. Spencer 1:f5ac63519541 806 pEntry->ttl = ntohl(ans.ttl);
Michael J. Spencer 1:f5ac63519541 807 if (pEntry->ttl > DNS_MAX_TTL) {
Michael J. Spencer 1:f5ac63519541 808 pEntry->ttl = DNS_MAX_TTL;
Michael J. Spencer 1:f5ac63519541 809 }
Michael J. Spencer 1:f5ac63519541 810 /* read the IP address after answer resource record's header */
Michael J. Spencer 1:f5ac63519541 811 SMEMCPY(&(pEntry->ipaddr), (pHostname+SIZEOF_DNS_ANSWER), sizeof(ip_addr_t));
Michael J. Spencer 1:f5ac63519541 812 LWIP_DEBUGF(DNS_DEBUG, ("dns_recv: \"%s\": response = ", pEntry->name));
Michael J. Spencer 1:f5ac63519541 813 ip_addr_debug_print(DNS_DEBUG, (&(pEntry->ipaddr)));
Michael J. Spencer 1:f5ac63519541 814 LWIP_DEBUGF(DNS_DEBUG, ("\n"));
Michael J. Spencer 1:f5ac63519541 815 /* call specified callback function if provided */
Michael J. Spencer 1:f5ac63519541 816 if (pEntry->found) {
Michael J. Spencer 1:f5ac63519541 817 (*pEntry->found)(pEntry->name, &pEntry->ipaddr, pEntry->arg);
Michael J. Spencer 1:f5ac63519541 818 }
Michael J. Spencer 1:f5ac63519541 819 /* deallocate memory and return */
Michael J. Spencer 1:f5ac63519541 820 goto memerr;
Michael J. Spencer 1:f5ac63519541 821 } else {
Michael J. Spencer 1:f5ac63519541 822 pHostname = pHostname + SIZEOF_DNS_ANSWER + htons(ans.len);
Michael J. Spencer 1:f5ac63519541 823 }
Michael J. Spencer 1:f5ac63519541 824 --nanswers;
Michael J. Spencer 1:f5ac63519541 825 }
Michael J. Spencer 1:f5ac63519541 826 LWIP_DEBUGF(DNS_DEBUG, ("dns_recv: \"%s\": error in response\n", pEntry->name));
Michael J. Spencer 1:f5ac63519541 827 /* call callback to indicate error, clean up memory and return */
Michael J. Spencer 1:f5ac63519541 828 goto responseerr;
Michael J. Spencer 1:f5ac63519541 829 }
Michael J. Spencer 1:f5ac63519541 830 }
Michael J. Spencer 1:f5ac63519541 831 }
Michael J. Spencer 1:f5ac63519541 832
Michael J. Spencer 1:f5ac63519541 833 /* deallocate memory and return */
Michael J. Spencer 1:f5ac63519541 834 goto memerr;
Michael J. Spencer 1:f5ac63519541 835
Michael J. Spencer 1:f5ac63519541 836 responseerr:
Michael J. Spencer 1:f5ac63519541 837 /* ERROR: call specified callback function with NULL as name to indicate an error */
Michael J. Spencer 1:f5ac63519541 838 if (pEntry->found) {
Michael J. Spencer 1:f5ac63519541 839 (*pEntry->found)(pEntry->name, NULL, pEntry->arg);
Michael J. Spencer 1:f5ac63519541 840 }
Michael J. Spencer 1:f5ac63519541 841 /* flush this entry */
Michael J. Spencer 1:f5ac63519541 842 pEntry->state = DNS_STATE_UNUSED;
Michael J. Spencer 1:f5ac63519541 843 pEntry->found = NULL;
Michael J. Spencer 1:f5ac63519541 844
Michael J. Spencer 1:f5ac63519541 845 memerr:
Michael J. Spencer 1:f5ac63519541 846 /* free pbuf */
Michael J. Spencer 1:f5ac63519541 847 pbuf_free(p);
Michael J. Spencer 1:f5ac63519541 848 return;
Michael J. Spencer 1:f5ac63519541 849 }
Michael J. Spencer 1:f5ac63519541 850
Michael J. Spencer 1:f5ac63519541 851 /**
Michael J. Spencer 1:f5ac63519541 852 * Queues a new hostname to resolve and sends out a DNS query for that hostname
Michael J. Spencer 1:f5ac63519541 853 *
Michael J. Spencer 1:f5ac63519541 854 * @param name the hostname that is to be queried
Michael J. Spencer 1:f5ac63519541 855 * @param found a callback founction to be called on success, failure or timeout
Michael J. Spencer 1:f5ac63519541 856 * @param callback_arg argument to pass to the callback function
Michael J. Spencer 1:f5ac63519541 857 * @return @return a err_t return code.
Michael J. Spencer 1:f5ac63519541 858 */
Michael J. Spencer 1:f5ac63519541 859 static err_t
Michael J. Spencer 1:f5ac63519541 860 dns_enqueue(const char *name, dns_found_callback found, void *callback_arg)
Michael J. Spencer 1:f5ac63519541 861 {
Michael J. Spencer 1:f5ac63519541 862 u8_t i;
Michael J. Spencer 1:f5ac63519541 863 u8_t lseq, lseqi;
Michael J. Spencer 1:f5ac63519541 864 struct dns_table_entry *pEntry = NULL;
Michael J. Spencer 1:f5ac63519541 865 size_t namelen;
Michael J. Spencer 1:f5ac63519541 866
Michael J. Spencer 1:f5ac63519541 867 /* search an unused entry, or the oldest one */
Michael J. Spencer 1:f5ac63519541 868 lseq = lseqi = 0;
Michael J. Spencer 1:f5ac63519541 869 for (i = 0; i < DNS_TABLE_SIZE; ++i) {
Michael J. Spencer 1:f5ac63519541 870 pEntry = &dns_table[i];
Michael J. Spencer 1:f5ac63519541 871 /* is it an unused entry ? */
Michael J. Spencer 1:f5ac63519541 872 if (pEntry->state == DNS_STATE_UNUSED)
Michael J. Spencer 1:f5ac63519541 873 break;
Michael J. Spencer 1:f5ac63519541 874
Michael J. Spencer 1:f5ac63519541 875 /* check if this is the oldest completed entry */
Michael J. Spencer 1:f5ac63519541 876 if (pEntry->state == DNS_STATE_DONE) {
Michael J. Spencer 1:f5ac63519541 877 if ((dns_seqno - pEntry->seqno) > lseq) {
Michael J. Spencer 1:f5ac63519541 878 lseq = dns_seqno - pEntry->seqno;
Michael J. Spencer 1:f5ac63519541 879 lseqi = i;
Michael J. Spencer 1:f5ac63519541 880 }
Michael J. Spencer 1:f5ac63519541 881 }
Michael J. Spencer 1:f5ac63519541 882 }
Michael J. Spencer 1:f5ac63519541 883
Michael J. Spencer 1:f5ac63519541 884 /* if we don't have found an unused entry, use the oldest completed one */
Michael J. Spencer 1:f5ac63519541 885 if (i == DNS_TABLE_SIZE) {
Michael J. Spencer 1:f5ac63519541 886 if ((lseqi >= DNS_TABLE_SIZE) || (dns_table[lseqi].state != DNS_STATE_DONE)) {
Michael J. Spencer 1:f5ac63519541 887 /* no entry can't be used now, table is full */
Michael J. Spencer 1:f5ac63519541 888 LWIP_DEBUGF(DNS_DEBUG, ("dns_enqueue: \"%s\": DNS entries table is full\n", name));
Michael J. Spencer 1:f5ac63519541 889 return ERR_MEM;
Michael J. Spencer 1:f5ac63519541 890 } else {
Michael J. Spencer 1:f5ac63519541 891 /* use the oldest completed one */
Michael J. Spencer 1:f5ac63519541 892 i = lseqi;
Michael J. Spencer 1:f5ac63519541 893 pEntry = &dns_table[i];
Michael J. Spencer 1:f5ac63519541 894 }
Michael J. Spencer 1:f5ac63519541 895 }
Michael J. Spencer 1:f5ac63519541 896
Michael J. Spencer 1:f5ac63519541 897 /* use this entry */
Michael J. Spencer 1:f5ac63519541 898 LWIP_DEBUGF(DNS_DEBUG, ("dns_enqueue: \"%s\": use DNS entry %"U16_F"\n", name, (u16_t)(i)));
Michael J. Spencer 1:f5ac63519541 899
Michael J. Spencer 1:f5ac63519541 900 /* fill the entry */
Michael J. Spencer 1:f5ac63519541 901 pEntry->state = DNS_STATE_NEW;
Michael J. Spencer 1:f5ac63519541 902 pEntry->seqno = dns_seqno++;
Michael J. Spencer 1:f5ac63519541 903 pEntry->found = found;
Michael J. Spencer 1:f5ac63519541 904 pEntry->arg = callback_arg;
Michael J. Spencer 1:f5ac63519541 905 namelen = LWIP_MIN(strlen(name), DNS_MAX_NAME_LENGTH-1);
Michael J. Spencer 1:f5ac63519541 906 MEMCPY(pEntry->name, name, namelen);
Michael J. Spencer 1:f5ac63519541 907 pEntry->name[namelen] = 0;
Michael J. Spencer 1:f5ac63519541 908
Michael J. Spencer 1:f5ac63519541 909 /* force to send query without waiting timer */
Michael J. Spencer 1:f5ac63519541 910 dns_check_entry(i);
Michael J. Spencer 1:f5ac63519541 911
Michael J. Spencer 1:f5ac63519541 912 /* dns query is enqueued */
Michael J. Spencer 1:f5ac63519541 913 return ERR_INPROGRESS;
Michael J. Spencer 1:f5ac63519541 914 }
Michael J. Spencer 1:f5ac63519541 915
Michael J. Spencer 1:f5ac63519541 916 /**
Michael J. Spencer 1:f5ac63519541 917 * Resolve a hostname (string) into an IP address.
Michael J. Spencer 1:f5ac63519541 918 * NON-BLOCKING callback version for use with raw API!!!
Michael J. Spencer 1:f5ac63519541 919 *
Michael J. Spencer 1:f5ac63519541 920 * Returns immediately with one of err_t return codes:
Michael J. Spencer 1:f5ac63519541 921 * - ERR_OK if hostname is a valid IP address string or the host
Michael J. Spencer 1:f5ac63519541 922 * name is already in the local names table.
Michael J. Spencer 1:f5ac63519541 923 * - ERR_INPROGRESS enqueue a request to be sent to the DNS server
Michael J. Spencer 1:f5ac63519541 924 * for resolution if no errors are present.
Michael J. Spencer 1:f5ac63519541 925 *
Michael J. Spencer 1:f5ac63519541 926 * @param hostname the hostname that is to be queried
Michael J. Spencer 1:f5ac63519541 927 * @param addr pointer to a ip_addr_t where to store the address if it is already
Michael J. Spencer 1:f5ac63519541 928 * cached in the dns_table (only valid if ERR_OK is returned!)
Michael J. Spencer 1:f5ac63519541 929 * @param found a callback function to be called on success, failure or timeout (only if
Michael J. Spencer 1:f5ac63519541 930 * ERR_INPROGRESS is returned!)
Michael J. Spencer 1:f5ac63519541 931 * @param callback_arg argument to pass to the callback function
Michael J. Spencer 1:f5ac63519541 932 * @return a err_t return code.
Michael J. Spencer 1:f5ac63519541 933 */
Michael J. Spencer 1:f5ac63519541 934 err_t
Michael J. Spencer 1:f5ac63519541 935 dns_gethostbyname(const char *hostname, ip_addr_t *addr, dns_found_callback found,
Michael J. Spencer 1:f5ac63519541 936 void *callback_arg)
Michael J. Spencer 1:f5ac63519541 937 {
Michael J. Spencer 1:f5ac63519541 938 u32_t ipaddr;
Michael J. Spencer 1:f5ac63519541 939 /* not initialized or no valid server yet, or invalid addr pointer
Michael J. Spencer 1:f5ac63519541 940 * or invalid hostname or invalid hostname length */
Michael J. Spencer 1:f5ac63519541 941 if ((dns_pcb == NULL) || (addr == NULL) ||
Michael J. Spencer 1:f5ac63519541 942 (!hostname) || (!hostname[0]) ||
Michael J. Spencer 1:f5ac63519541 943 (strlen(hostname) >= DNS_MAX_NAME_LENGTH)) {
Michael J. Spencer 1:f5ac63519541 944 return ERR_VAL;
Michael J. Spencer 1:f5ac63519541 945 }
Michael J. Spencer 1:f5ac63519541 946
Michael J. Spencer 1:f5ac63519541 947 #if LWIP_HAVE_LOOPIF
Michael J. Spencer 1:f5ac63519541 948 if (strcmp(hostname, "localhost")==0) {
Michael J. Spencer 1:f5ac63519541 949 ip_addr_set_loopback(addr);
Michael J. Spencer 1:f5ac63519541 950 return ERR_OK;
Michael J. Spencer 1:f5ac63519541 951 }
Michael J. Spencer 1:f5ac63519541 952 #endif /* LWIP_HAVE_LOOPIF */
Michael J. Spencer 1:f5ac63519541 953
Michael J. Spencer 1:f5ac63519541 954 /* host name already in octet notation? set ip addr and return ERR_OK */
Michael J. Spencer 1:f5ac63519541 955 ipaddr = ipaddr_addr(hostname);
Michael J. Spencer 1:f5ac63519541 956 if (ipaddr == IPADDR_NONE) {
Michael J. Spencer 1:f5ac63519541 957 /* already have this address cached? */
Michael J. Spencer 1:f5ac63519541 958 ipaddr = dns_lookup(hostname);
Michael J. Spencer 1:f5ac63519541 959 }
Michael J. Spencer 1:f5ac63519541 960 if (ipaddr != IPADDR_NONE) {
Michael J. Spencer 1:f5ac63519541 961 ip4_addr_set_u32(addr, ipaddr);
Michael J. Spencer 1:f5ac63519541 962 return ERR_OK;
Michael J. Spencer 1:f5ac63519541 963 }
Michael J. Spencer 1:f5ac63519541 964
Michael J. Spencer 1:f5ac63519541 965 /* queue query with specified callback */
Michael J. Spencer 1:f5ac63519541 966 return dns_enqueue(hostname, found, callback_arg);
Michael J. Spencer 1:f5ac63519541 967 }
Michael J. Spencer 1:f5ac63519541 968
Michael J. Spencer 1:f5ac63519541 969 #endif /* LWIP_DNS */