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NetServices/lwip/core/dns.c@0:05ccbd4f84f1, 2013-12-02 (annotated)

Committer:
hendrikvincent
Date:
Mon Dec 02 09:01:23 2013 +0000
Revision:
0:05ccbd4f84f1
eerste programma;

Who changed what in which revision?

UserRevisionLine numberNew contents of line
hendrikvincent 0:05ccbd4f84f1 1 /**
hendrikvincent 0:05ccbd4f84f1 2 * @file
hendrikvincent 0:05ccbd4f84f1 3 * DNS - host name to IP address resolver.
hendrikvincent 0:05ccbd4f84f1 4 *
hendrikvincent 0:05ccbd4f84f1 5 */
hendrikvincent 0:05ccbd4f84f1 6
hendrikvincent 0:05ccbd4f84f1 7 /**
hendrikvincent 0:05ccbd4f84f1 8
hendrikvincent 0:05ccbd4f84f1 9 * This file implements a DNS host name to IP address resolver.
hendrikvincent 0:05ccbd4f84f1 10
hendrikvincent 0:05ccbd4f84f1 11 * Port to lwIP from uIP
hendrikvincent 0:05ccbd4f84f1 12 * by Jim Pettinato April 2007
hendrikvincent 0:05ccbd4f84f1 13
hendrikvincent 0:05ccbd4f84f1 14 * uIP version Copyright (c) 2002-2003, Adam Dunkels.
hendrikvincent 0:05ccbd4f84f1 15 * All rights reserved.
hendrikvincent 0:05ccbd4f84f1 16 *
hendrikvincent 0:05ccbd4f84f1 17 * Redistribution and use in source and binary forms, with or without
hendrikvincent 0:05ccbd4f84f1 18 * modification, are permitted provided that the following conditions
hendrikvincent 0:05ccbd4f84f1 19 * are met:
hendrikvincent 0:05ccbd4f84f1 20 * 1. Redistributions of source code must retain the above copyright
hendrikvincent 0:05ccbd4f84f1 21 * notice, this list of conditions and the following disclaimer.
hendrikvincent 0:05ccbd4f84f1 22 * 2. Redistributions in binary form must reproduce the above copyright
hendrikvincent 0:05ccbd4f84f1 23 * notice, this list of conditions and the following disclaimer in the
hendrikvincent 0:05ccbd4f84f1 24 * documentation and/or other materials provided with the distribution.
hendrikvincent 0:05ccbd4f84f1 25 * 3. The name of the author may not be used to endorse or promote
hendrikvincent 0:05ccbd4f84f1 26 * products derived from this software without specific prior
hendrikvincent 0:05ccbd4f84f1 27 * written permission.
hendrikvincent 0:05ccbd4f84f1 28 *
hendrikvincent 0:05ccbd4f84f1 29 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
hendrikvincent 0:05ccbd4f84f1 30 * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
hendrikvincent 0:05ccbd4f84f1 31 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
hendrikvincent 0:05ccbd4f84f1 32 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
hendrikvincent 0:05ccbd4f84f1 33 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
hendrikvincent 0:05ccbd4f84f1 34 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
hendrikvincent 0:05ccbd4f84f1 35 * GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
hendrikvincent 0:05ccbd4f84f1 36 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
hendrikvincent 0:05ccbd4f84f1 37 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
hendrikvincent 0:05ccbd4f84f1 38 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
hendrikvincent 0:05ccbd4f84f1 39 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
hendrikvincent 0:05ccbd4f84f1 40 *
hendrikvincent 0:05ccbd4f84f1 41 *
hendrikvincent 0:05ccbd4f84f1 42 * DNS.C
hendrikvincent 0:05ccbd4f84f1 43 *
hendrikvincent 0:05ccbd4f84f1 44 * The lwIP DNS resolver functions are used to lookup a host name and
hendrikvincent 0:05ccbd4f84f1 45 * map it to a numerical IP address. It maintains a list of resolved
hendrikvincent 0:05ccbd4f84f1 46 * hostnames that can be queried with the dns_lookup() function.
hendrikvincent 0:05ccbd4f84f1 47 * New hostnames can be resolved using the dns_query() function.
hendrikvincent 0:05ccbd4f84f1 48 *
hendrikvincent 0:05ccbd4f84f1 49 * The lwIP version of the resolver also adds a non-blocking version of
hendrikvincent 0:05ccbd4f84f1 50 * gethostbyname() that will work with a raw API application. This function
hendrikvincent 0:05ccbd4f84f1 51 * checks for an IP address string first and converts it if it is valid.
hendrikvincent 0:05ccbd4f84f1 52 * gethostbyname() then does a dns_lookup() to see if the name is
hendrikvincent 0:05ccbd4f84f1 53 * already in the table. If so, the IP is returned. If not, a query is
hendrikvincent 0:05ccbd4f84f1 54 * issued and the function returns with a ERR_INPROGRESS status. The app
hendrikvincent 0:05ccbd4f84f1 55 * using the dns client must then go into a waiting state.
hendrikvincent 0:05ccbd4f84f1 56 *
hendrikvincent 0:05ccbd4f84f1 57 * Once a hostname has been resolved (or found to be non-existent),
hendrikvincent 0:05ccbd4f84f1 58 * the resolver code calls a specified callback function (which
hendrikvincent 0:05ccbd4f84f1 59 * must be implemented by the module that uses the resolver).
hendrikvincent 0:05ccbd4f84f1 60 */
hendrikvincent 0:05ccbd4f84f1 61
hendrikvincent 0:05ccbd4f84f1 62 /*-----------------------------------------------------------------------------
hendrikvincent 0:05ccbd4f84f1 63 * RFC 1035 - Domain names - implementation and specification
hendrikvincent 0:05ccbd4f84f1 64 * RFC 2181 - Clarifications to the DNS Specification
hendrikvincent 0:05ccbd4f84f1 65 *----------------------------------------------------------------------------*/
hendrikvincent 0:05ccbd4f84f1 66
hendrikvincent 0:05ccbd4f84f1 67 /** @todo: define good default values (rfc compliance) */
hendrikvincent 0:05ccbd4f84f1 68 /** @todo: improve answer parsing, more checkings... */
hendrikvincent 0:05ccbd4f84f1 69 /** @todo: check RFC1035 - 7.3. Processing responses */
hendrikvincent 0:05ccbd4f84f1 70
hendrikvincent 0:05ccbd4f84f1 71 /*-----------------------------------------------------------------------------
hendrikvincent 0:05ccbd4f84f1 72 * Includes
hendrikvincent 0:05ccbd4f84f1 73 *----------------------------------------------------------------------------*/
hendrikvincent 0:05ccbd4f84f1 74
hendrikvincent 0:05ccbd4f84f1 75 #include "lwip/opt.h"
hendrikvincent 0:05ccbd4f84f1 76
hendrikvincent 0:05ccbd4f84f1 77 #if LWIP_DNS /* don't build if not configured for use in lwipopts.h */
hendrikvincent 0:05ccbd4f84f1 78
hendrikvincent 0:05ccbd4f84f1 79 #include "lwip/udp.h"
hendrikvincent 0:05ccbd4f84f1 80 #include "lwip/mem.h"
hendrikvincent 0:05ccbd4f84f1 81 #include "lwip/memp.h"
hendrikvincent 0:05ccbd4f84f1 82 #include "lwip/dns.h"
hendrikvincent 0:05ccbd4f84f1 83
hendrikvincent 0:05ccbd4f84f1 84 #include <string.h>
hendrikvincent 0:05ccbd4f84f1 85
hendrikvincent 0:05ccbd4f84f1 86 /** DNS server IP address */
hendrikvincent 0:05ccbd4f84f1 87 #ifndef DNS_SERVER_ADDRESS
hendrikvincent 0:05ccbd4f84f1 88 #define DNS_SERVER_ADDRESS(ipaddr) (ip4_addr_set_u32(ipaddr, ipaddr_addr("208.67.222.222"))) /* resolver1.opendns.com */
hendrikvincent 0:05ccbd4f84f1 89 #endif
hendrikvincent 0:05ccbd4f84f1 90
hendrikvincent 0:05ccbd4f84f1 91 /** DNS server port address */
hendrikvincent 0:05ccbd4f84f1 92 #ifndef DNS_SERVER_PORT
hendrikvincent 0:05ccbd4f84f1 93 #define DNS_SERVER_PORT 53
hendrikvincent 0:05ccbd4f84f1 94 #endif
hendrikvincent 0:05ccbd4f84f1 95
hendrikvincent 0:05ccbd4f84f1 96 /** DNS maximum number of retries when asking for a name, before "timeout". */
hendrikvincent 0:05ccbd4f84f1 97 #ifndef DNS_MAX_RETRIES
hendrikvincent 0:05ccbd4f84f1 98 #define DNS_MAX_RETRIES 4
hendrikvincent 0:05ccbd4f84f1 99 #endif
hendrikvincent 0:05ccbd4f84f1 100
hendrikvincent 0:05ccbd4f84f1 101 /** DNS resource record max. TTL (one week as default) */
hendrikvincent 0:05ccbd4f84f1 102 #ifndef DNS_MAX_TTL
hendrikvincent 0:05ccbd4f84f1 103 #define DNS_MAX_TTL 604800
hendrikvincent 0:05ccbd4f84f1 104 #endif
hendrikvincent 0:05ccbd4f84f1 105
hendrikvincent 0:05ccbd4f84f1 106 /* DNS protocol flags */
hendrikvincent 0:05ccbd4f84f1 107 #define DNS_FLAG1_RESPONSE 0x80
hendrikvincent 0:05ccbd4f84f1 108 #define DNS_FLAG1_OPCODE_STATUS 0x10
hendrikvincent 0:05ccbd4f84f1 109 #define DNS_FLAG1_OPCODE_INVERSE 0x08
hendrikvincent 0:05ccbd4f84f1 110 #define DNS_FLAG1_OPCODE_STANDARD 0x00
hendrikvincent 0:05ccbd4f84f1 111 #define DNS_FLAG1_AUTHORATIVE 0x04
hendrikvincent 0:05ccbd4f84f1 112 #define DNS_FLAG1_TRUNC 0x02
hendrikvincent 0:05ccbd4f84f1 113 #define DNS_FLAG1_RD 0x01
hendrikvincent 0:05ccbd4f84f1 114 #define DNS_FLAG2_RA 0x80
hendrikvincent 0:05ccbd4f84f1 115 #define DNS_FLAG2_ERR_MASK 0x0f
hendrikvincent 0:05ccbd4f84f1 116 #define DNS_FLAG2_ERR_NONE 0x00
hendrikvincent 0:05ccbd4f84f1 117 #define DNS_FLAG2_ERR_NAME 0x03
hendrikvincent 0:05ccbd4f84f1 118
hendrikvincent 0:05ccbd4f84f1 119 /* DNS protocol states */
hendrikvincent 0:05ccbd4f84f1 120 #define DNS_STATE_UNUSED 0
hendrikvincent 0:05ccbd4f84f1 121 #define DNS_STATE_NEW 1
hendrikvincent 0:05ccbd4f84f1 122 #define DNS_STATE_ASKING 2
hendrikvincent 0:05ccbd4f84f1 123 #define DNS_STATE_DONE 3
hendrikvincent 0:05ccbd4f84f1 124
hendrikvincent 0:05ccbd4f84f1 125 #ifdef PACK_STRUCT_USE_INCLUDES
hendrikvincent 0:05ccbd4f84f1 126 # include "arch/bpstruct.h"
hendrikvincent 0:05ccbd4f84f1 127 #endif
hendrikvincent 0:05ccbd4f84f1 128 PACK_STRUCT_BEGIN
hendrikvincent 0:05ccbd4f84f1 129 /** DNS message header */
hendrikvincent 0:05ccbd4f84f1 130 struct dns_hdr {
hendrikvincent 0:05ccbd4f84f1 131 PACK_STRUCT_FIELD(u16_t id);
hendrikvincent 0:05ccbd4f84f1 132 PACK_STRUCT_FIELD(u8_t flags1);
hendrikvincent 0:05ccbd4f84f1 133 PACK_STRUCT_FIELD(u8_t flags2);
hendrikvincent 0:05ccbd4f84f1 134 PACK_STRUCT_FIELD(u16_t numquestions);
hendrikvincent 0:05ccbd4f84f1 135 PACK_STRUCT_FIELD(u16_t numanswers);
hendrikvincent 0:05ccbd4f84f1 136 PACK_STRUCT_FIELD(u16_t numauthrr);
hendrikvincent 0:05ccbd4f84f1 137 PACK_STRUCT_FIELD(u16_t numextrarr);
hendrikvincent 0:05ccbd4f84f1 138 } PACK_STRUCT_STRUCT;
hendrikvincent 0:05ccbd4f84f1 139 PACK_STRUCT_END
hendrikvincent 0:05ccbd4f84f1 140 #ifdef PACK_STRUCT_USE_INCLUDES
hendrikvincent 0:05ccbd4f84f1 141 # include "arch/epstruct.h"
hendrikvincent 0:05ccbd4f84f1 142 #endif
hendrikvincent 0:05ccbd4f84f1 143 #define SIZEOF_DNS_HDR 12
hendrikvincent 0:05ccbd4f84f1 144
hendrikvincent 0:05ccbd4f84f1 145 /** DNS query message structure.
hendrikvincent 0:05ccbd4f84f1 146 No packing needed: only used locally on the stack. */
hendrikvincent 0:05ccbd4f84f1 147 struct dns_query {
hendrikvincent 0:05ccbd4f84f1 148 /* DNS query record starts with either a domain name or a pointer
hendrikvincent 0:05ccbd4f84f1 149 to a name already present somewhere in the packet. */
hendrikvincent 0:05ccbd4f84f1 150 u16_t type;
hendrikvincent 0:05ccbd4f84f1 151 u16_t cls;
hendrikvincent 0:05ccbd4f84f1 152 };
hendrikvincent 0:05ccbd4f84f1 153 #define SIZEOF_DNS_QUERY 4
hendrikvincent 0:05ccbd4f84f1 154
hendrikvincent 0:05ccbd4f84f1 155 /** DNS answer message structure.
hendrikvincent 0:05ccbd4f84f1 156 No packing needed: only used locally on the stack. */
hendrikvincent 0:05ccbd4f84f1 157 struct dns_answer {
hendrikvincent 0:05ccbd4f84f1 158 /* DNS answer record starts with either a domain name or a pointer
hendrikvincent 0:05ccbd4f84f1 159 to a name already present somewhere in the packet. */
hendrikvincent 0:05ccbd4f84f1 160 u16_t type;
hendrikvincent 0:05ccbd4f84f1 161 u16_t cls;
hendrikvincent 0:05ccbd4f84f1 162 u32_t ttl;
hendrikvincent 0:05ccbd4f84f1 163 u16_t len;
hendrikvincent 0:05ccbd4f84f1 164 };
hendrikvincent 0:05ccbd4f84f1 165 #define SIZEOF_DNS_ANSWER 10
hendrikvincent 0:05ccbd4f84f1 166
hendrikvincent 0:05ccbd4f84f1 167 /** DNS table entry */
hendrikvincent 0:05ccbd4f84f1 168 struct dns_table_entry {
hendrikvincent 0:05ccbd4f84f1 169 u8_t state;
hendrikvincent 0:05ccbd4f84f1 170 u8_t numdns;
hendrikvincent 0:05ccbd4f84f1 171 u8_t tmr;
hendrikvincent 0:05ccbd4f84f1 172 u8_t retries;
hendrikvincent 0:05ccbd4f84f1 173 u8_t seqno;
hendrikvincent 0:05ccbd4f84f1 174 u8_t err;
hendrikvincent 0:05ccbd4f84f1 175 u32_t ttl;
hendrikvincent 0:05ccbd4f84f1 176 char name[DNS_MAX_NAME_LENGTH];
hendrikvincent 0:05ccbd4f84f1 177 ip_addr_t ipaddr;
hendrikvincent 0:05ccbd4f84f1 178 /* pointer to callback on DNS query done */
hendrikvincent 0:05ccbd4f84f1 179 dns_found_callback found;
hendrikvincent 0:05ccbd4f84f1 180 void *arg;
hendrikvincent 0:05ccbd4f84f1 181 };
hendrikvincent 0:05ccbd4f84f1 182
hendrikvincent 0:05ccbd4f84f1 183 #if DNS_LOCAL_HOSTLIST
hendrikvincent 0:05ccbd4f84f1 184
hendrikvincent 0:05ccbd4f84f1 185 #if DNS_LOCAL_HOSTLIST_IS_DYNAMIC
hendrikvincent 0:05ccbd4f84f1 186 /** Local host-list. For hostnames in this list, no
hendrikvincent 0:05ccbd4f84f1 187 * external name resolution is performed */
hendrikvincent 0:05ccbd4f84f1 188 static struct local_hostlist_entry *local_hostlist_dynamic;
hendrikvincent 0:05ccbd4f84f1 189 #else /* DNS_LOCAL_HOSTLIST_IS_DYNAMIC */
hendrikvincent 0:05ccbd4f84f1 190
hendrikvincent 0:05ccbd4f84f1 191 /** Defining this allows the local_hostlist_static to be placed in a different
hendrikvincent 0:05ccbd4f84f1 192 * linker section (e.g. FLASH) */
hendrikvincent 0:05ccbd4f84f1 193 #ifndef DNS_LOCAL_HOSTLIST_STORAGE_PRE
hendrikvincent 0:05ccbd4f84f1 194 #define DNS_LOCAL_HOSTLIST_STORAGE_PRE static
hendrikvincent 0:05ccbd4f84f1 195 #endif /* DNS_LOCAL_HOSTLIST_STORAGE_PRE */
hendrikvincent 0:05ccbd4f84f1 196 /** Defining this allows the local_hostlist_static to be placed in a different
hendrikvincent 0:05ccbd4f84f1 197 * linker section (e.g. FLASH) */
hendrikvincent 0:05ccbd4f84f1 198 #ifndef DNS_LOCAL_HOSTLIST_STORAGE_POST
hendrikvincent 0:05ccbd4f84f1 199 #define DNS_LOCAL_HOSTLIST_STORAGE_POST
hendrikvincent 0:05ccbd4f84f1 200 #endif /* DNS_LOCAL_HOSTLIST_STORAGE_POST */
hendrikvincent 0:05ccbd4f84f1 201 DNS_LOCAL_HOSTLIST_STORAGE_PRE struct local_hostlist_entry local_hostlist_static[]
hendrikvincent 0:05ccbd4f84f1 202 DNS_LOCAL_HOSTLIST_STORAGE_POST = DNS_LOCAL_HOSTLIST_INIT;
hendrikvincent 0:05ccbd4f84f1 203
hendrikvincent 0:05ccbd4f84f1 204 #endif /* DNS_LOCAL_HOSTLIST_IS_DYNAMIC */
hendrikvincent 0:05ccbd4f84f1 205
hendrikvincent 0:05ccbd4f84f1 206 static void dns_init_local();
hendrikvincent 0:05ccbd4f84f1 207 #endif /* DNS_LOCAL_HOSTLIST */
hendrikvincent 0:05ccbd4f84f1 208
hendrikvincent 0:05ccbd4f84f1 209
hendrikvincent 0:05ccbd4f84f1 210 /* forward declarations */
hendrikvincent 0:05ccbd4f84f1 211 static void dns_recv(void *s, struct udp_pcb *pcb, struct pbuf *p, ip_addr_t *addr, u16_t port);
hendrikvincent 0:05ccbd4f84f1 212 static void dns_check_entries(void);
hendrikvincent 0:05ccbd4f84f1 213
hendrikvincent 0:05ccbd4f84f1 214 /*-----------------------------------------------------------------------------
hendrikvincent 0:05ccbd4f84f1 215 * Globales
hendrikvincent 0:05ccbd4f84f1 216 *----------------------------------------------------------------------------*/
hendrikvincent 0:05ccbd4f84f1 217
hendrikvincent 0:05ccbd4f84f1 218 /* DNS variables */
hendrikvincent 0:05ccbd4f84f1 219 static struct udp_pcb *dns_pcb;
hendrikvincent 0:05ccbd4f84f1 220 static u8_t dns_seqno;
hendrikvincent 0:05ccbd4f84f1 221 static struct dns_table_entry dns_table[DNS_TABLE_SIZE];
hendrikvincent 0:05ccbd4f84f1 222 static ip_addr_t dns_servers[DNS_MAX_SERVERS];
hendrikvincent 0:05ccbd4f84f1 223 /** Contiguous buffer for processing responses */
hendrikvincent 0:05ccbd4f84f1 224 static u8_t dns_payload_buffer[LWIP_MEM_ALIGN_BUFFER(DNS_MSG_SIZE)];
hendrikvincent 0:05ccbd4f84f1 225 static u8_t* dns_payload;
hendrikvincent 0:05ccbd4f84f1 226
hendrikvincent 0:05ccbd4f84f1 227 /**
hendrikvincent 0:05ccbd4f84f1 228 * Initialize the resolver: set up the UDP pcb and configure the default server
hendrikvincent 0:05ccbd4f84f1 229 * (DNS_SERVER_ADDRESS).
hendrikvincent 0:05ccbd4f84f1 230 */
hendrikvincent 0:05ccbd4f84f1 231 void
hendrikvincent 0:05ccbd4f84f1 232 dns_init()
hendrikvincent 0:05ccbd4f84f1 233 {
hendrikvincent 0:05ccbd4f84f1 234 ip_addr_t dnsserver;
hendrikvincent 0:05ccbd4f84f1 235
hendrikvincent 0:05ccbd4f84f1 236 dns_payload = (u8_t *)LWIP_MEM_ALIGN(dns_payload_buffer);
hendrikvincent 0:05ccbd4f84f1 237
hendrikvincent 0:05ccbd4f84f1 238 /* initialize default DNS server address */
hendrikvincent 0:05ccbd4f84f1 239 DNS_SERVER_ADDRESS(&dnsserver);
hendrikvincent 0:05ccbd4f84f1 240
hendrikvincent 0:05ccbd4f84f1 241 LWIP_DEBUGF(DNS_DEBUG, ("dns_init: initializing\n"));
hendrikvincent 0:05ccbd4f84f1 242
hendrikvincent 0:05ccbd4f84f1 243 /* if dns client not yet initialized... */
hendrikvincent 0:05ccbd4f84f1 244 if (dns_pcb == NULL) {
hendrikvincent 0:05ccbd4f84f1 245 dns_pcb = udp_new();
hendrikvincent 0:05ccbd4f84f1 246
hendrikvincent 0:05ccbd4f84f1 247 if (dns_pcb != NULL) {
hendrikvincent 0:05ccbd4f84f1 248 /* initialize DNS table not needed (initialized to zero since it is a
hendrikvincent 0:05ccbd4f84f1 249 * global variable) */
hendrikvincent 0:05ccbd4f84f1 250 LWIP_ASSERT("For implicit initialization to work, DNS_STATE_UNUSED needs to be 0",
hendrikvincent 0:05ccbd4f84f1 251 DNS_STATE_UNUSED == 0);
hendrikvincent 0:05ccbd4f84f1 252
hendrikvincent 0:05ccbd4f84f1 253 /* initialize DNS client */
hendrikvincent 0:05ccbd4f84f1 254 udp_bind(dns_pcb, IP_ADDR_ANY, 0);
hendrikvincent 0:05ccbd4f84f1 255 udp_recv(dns_pcb, dns_recv, NULL);
hendrikvincent 0:05ccbd4f84f1 256
hendrikvincent 0:05ccbd4f84f1 257 /* initialize default DNS primary server */
hendrikvincent 0:05ccbd4f84f1 258 dns_setserver(0, &dnsserver);
hendrikvincent 0:05ccbd4f84f1 259 }
hendrikvincent 0:05ccbd4f84f1 260 }
hendrikvincent 0:05ccbd4f84f1 261 #if DNS_LOCAL_HOSTLIST
hendrikvincent 0:05ccbd4f84f1 262 dns_init_local();
hendrikvincent 0:05ccbd4f84f1 263 #endif
hendrikvincent 0:05ccbd4f84f1 264 }
hendrikvincent 0:05ccbd4f84f1 265
hendrikvincent 0:05ccbd4f84f1 266 /**
hendrikvincent 0:05ccbd4f84f1 267 * Initialize one of the DNS servers.
hendrikvincent 0:05ccbd4f84f1 268 *
hendrikvincent 0:05ccbd4f84f1 269 * @param numdns the index of the DNS server to set must be < DNS_MAX_SERVERS
hendrikvincent 0:05ccbd4f84f1 270 * @param dnsserver IP address of the DNS server to set
hendrikvincent 0:05ccbd4f84f1 271 */
hendrikvincent 0:05ccbd4f84f1 272 void
hendrikvincent 0:05ccbd4f84f1 273 dns_setserver(u8_t numdns, ip_addr_t *dnsserver)
hendrikvincent 0:05ccbd4f84f1 274 {
hendrikvincent 0:05ccbd4f84f1 275 if ((numdns < DNS_MAX_SERVERS) && (dns_pcb != NULL) &&
hendrikvincent 0:05ccbd4f84f1 276 (dnsserver != NULL) && !ip_addr_isany(dnsserver)) {
hendrikvincent 0:05ccbd4f84f1 277 dns_servers[numdns] = (*dnsserver);
hendrikvincent 0:05ccbd4f84f1 278 }
hendrikvincent 0:05ccbd4f84f1 279 }
hendrikvincent 0:05ccbd4f84f1 280
hendrikvincent 0:05ccbd4f84f1 281 /**
hendrikvincent 0:05ccbd4f84f1 282 * Obtain one of the currently configured DNS server.
hendrikvincent 0:05ccbd4f84f1 283 *
hendrikvincent 0:05ccbd4f84f1 284 * @param numdns the index of the DNS server
hendrikvincent 0:05ccbd4f84f1 285 * @return IP address of the indexed DNS server or "ip_addr_any" if the DNS
hendrikvincent 0:05ccbd4f84f1 286 * server has not been configured.
hendrikvincent 0:05ccbd4f84f1 287 */
hendrikvincent 0:05ccbd4f84f1 288 ip_addr_t
hendrikvincent 0:05ccbd4f84f1 289 dns_getserver(u8_t numdns)
hendrikvincent 0:05ccbd4f84f1 290 {
hendrikvincent 0:05ccbd4f84f1 291 if (numdns < DNS_MAX_SERVERS) {
hendrikvincent 0:05ccbd4f84f1 292 return dns_servers[numdns];
hendrikvincent 0:05ccbd4f84f1 293 } else {
hendrikvincent 0:05ccbd4f84f1 294 return *IP_ADDR_ANY;
hendrikvincent 0:05ccbd4f84f1 295 }
hendrikvincent 0:05ccbd4f84f1 296 }
hendrikvincent 0:05ccbd4f84f1 297
hendrikvincent 0:05ccbd4f84f1 298 /**
hendrikvincent 0:05ccbd4f84f1 299 * The DNS resolver client timer - handle retries and timeouts and should
hendrikvincent 0:05ccbd4f84f1 300 * be called every DNS_TMR_INTERVAL milliseconds (every second by default).
hendrikvincent 0:05ccbd4f84f1 301 */
hendrikvincent 0:05ccbd4f84f1 302 void
hendrikvincent 0:05ccbd4f84f1 303 dns_tmr(void)
hendrikvincent 0:05ccbd4f84f1 304 {
hendrikvincent 0:05ccbd4f84f1 305 if (dns_pcb != NULL) {
hendrikvincent 0:05ccbd4f84f1 306 LWIP_DEBUGF(DNS_DEBUG, ("dns_tmr: dns_check_entries\n"));
hendrikvincent 0:05ccbd4f84f1 307 dns_check_entries();
hendrikvincent 0:05ccbd4f84f1 308 }
hendrikvincent 0:05ccbd4f84f1 309 }
hendrikvincent 0:05ccbd4f84f1 310
hendrikvincent 0:05ccbd4f84f1 311 #if DNS_LOCAL_HOSTLIST
hendrikvincent 0:05ccbd4f84f1 312 static void
hendrikvincent 0:05ccbd4f84f1 313 dns_init_local()
hendrikvincent 0:05ccbd4f84f1 314 {
hendrikvincent 0:05ccbd4f84f1 315 #if DNS_LOCAL_HOSTLIST_IS_DYNAMIC && defined(DNS_LOCAL_HOSTLIST_INIT)
hendrikvincent 0:05ccbd4f84f1 316 int i;
hendrikvincent 0:05ccbd4f84f1 317 struct local_hostlist_entry *entry;
hendrikvincent 0:05ccbd4f84f1 318 /* Dynamic: copy entries from DNS_LOCAL_HOSTLIST_INIT to list */
hendrikvincent 0:05ccbd4f84f1 319 struct local_hostlist_entry local_hostlist_init[] = DNS_LOCAL_HOSTLIST_INIT;
hendrikvincent 0:05ccbd4f84f1 320 size_t namelen;
hendrikvincent 0:05ccbd4f84f1 321 for (i = 0; i < sizeof(local_hostlist_init) / sizeof(struct local_hostlist_entry); i++) {
hendrikvincent 0:05ccbd4f84f1 322 struct local_hostlist_entry *init_entry = &local_hostlist_init[i];
hendrikvincent 0:05ccbd4f84f1 323 LWIP_ASSERT("invalid host name (NULL)", init_entry->name != NULL);
hendrikvincent 0:05ccbd4f84f1 324 namelen = strlen(init_entry->name);
hendrikvincent 0:05ccbd4f84f1 325 LWIP_ASSERT("namelen <= DNS_LOCAL_HOSTLIST_MAX_NAMELEN", namelen <= DNS_LOCAL_HOSTLIST_MAX_NAMELEN);
hendrikvincent 0:05ccbd4f84f1 326 entry = (struct local_hostlist_entry *)memp_malloc(MEMP_LOCALHOSTLIST);
hendrikvincent 0:05ccbd4f84f1 327 LWIP_ASSERT("mem-error in dns_init_local", entry != NULL);
hendrikvincent 0:05ccbd4f84f1 328 if (entry != NULL) {
hendrikvincent 0:05ccbd4f84f1 329 entry->name = (char*)entry + sizeof(struct local_hostlist_entry);
hendrikvincent 0:05ccbd4f84f1 330 MEMCPY((char*)entry->name, init_entry->name, namelen);
hendrikvincent 0:05ccbd4f84f1 331 ((char*)entry->name)[namelen] = 0;
hendrikvincent 0:05ccbd4f84f1 332 entry->addr = init_entry->addr;
hendrikvincent 0:05ccbd4f84f1 333 entry->next = local_hostlist_dynamic;
hendrikvincent 0:05ccbd4f84f1 334 local_hostlist_dynamic = entry;
hendrikvincent 0:05ccbd4f84f1 335 }
hendrikvincent 0:05ccbd4f84f1 336 }
hendrikvincent 0:05ccbd4f84f1 337 #endif /* DNS_LOCAL_HOSTLIST_IS_DYNAMIC && defined(DNS_LOCAL_HOSTLIST_INIT) */
hendrikvincent 0:05ccbd4f84f1 338 }
hendrikvincent 0:05ccbd4f84f1 339
hendrikvincent 0:05ccbd4f84f1 340 /**
hendrikvincent 0:05ccbd4f84f1 341 * Scans the local host-list for a hostname.
hendrikvincent 0:05ccbd4f84f1 342 *
hendrikvincent 0:05ccbd4f84f1 343 * @param hostname Hostname to look for in the local host-list
hendrikvincent 0:05ccbd4f84f1 344 * @return The first IP address for the hostname in the local host-list or
hendrikvincent 0:05ccbd4f84f1 345 * IPADDR_NONE if not found.
hendrikvincent 0:05ccbd4f84f1 346 */
hendrikvincent 0:05ccbd4f84f1 347 static u32_t
hendrikvincent 0:05ccbd4f84f1 348 dns_lookup_local(const char *hostname)
hendrikvincent 0:05ccbd4f84f1 349 {
hendrikvincent 0:05ccbd4f84f1 350 #if DNS_LOCAL_HOSTLIST_IS_DYNAMIC
hendrikvincent 0:05ccbd4f84f1 351 struct local_hostlist_entry *entry = local_hostlist_dynamic;
hendrikvincent 0:05ccbd4f84f1 352 while(entry != NULL) {
hendrikvincent 0:05ccbd4f84f1 353 if(strcmp(entry->name, hostname) == 0) {
hendrikvincent 0:05ccbd4f84f1 354 return ip4_addr_get_u32(&entry->addr);
hendrikvincent 0:05ccbd4f84f1 355 }
hendrikvincent 0:05ccbd4f84f1 356 entry = entry->next;
hendrikvincent 0:05ccbd4f84f1 357 }
hendrikvincent 0:05ccbd4f84f1 358 #else /* DNS_LOCAL_HOSTLIST_IS_DYNAMIC */
hendrikvincent 0:05ccbd4f84f1 359 int i;
hendrikvincent 0:05ccbd4f84f1 360 for (i = 0; i < sizeof(local_hostlist_static) / sizeof(struct local_hostlist_entry); i++) {
hendrikvincent 0:05ccbd4f84f1 361 if(strcmp(local_hostlist_static[i].name, hostname) == 0) {
hendrikvincent 0:05ccbd4f84f1 362 return ip4_addr_get_u32(&local_hostlist_static[i].addr);
hendrikvincent 0:05ccbd4f84f1 363 }
hendrikvincent 0:05ccbd4f84f1 364 }
hendrikvincent 0:05ccbd4f84f1 365 #endif /* DNS_LOCAL_HOSTLIST_IS_DYNAMIC */
hendrikvincent 0:05ccbd4f84f1 366 return IPADDR_NONE;
hendrikvincent 0:05ccbd4f84f1 367 }
hendrikvincent 0:05ccbd4f84f1 368
hendrikvincent 0:05ccbd4f84f1 369 #if DNS_LOCAL_HOSTLIST_IS_DYNAMIC
hendrikvincent 0:05ccbd4f84f1 370 /** Remove all entries from the local host-list for a specific hostname
hendrikvincent 0:05ccbd4f84f1 371 * and/or IP addess
hendrikvincent 0:05ccbd4f84f1 372 *
hendrikvincent 0:05ccbd4f84f1 373 * @param hostname hostname for which entries shall be removed from the local
hendrikvincent 0:05ccbd4f84f1 374 * host-list
hendrikvincent 0:05ccbd4f84f1 375 * @param addr address for which entries shall be removed from the local host-list
hendrikvincent 0:05ccbd4f84f1 376 * @return the number of removed entries
hendrikvincent 0:05ccbd4f84f1 377 */
hendrikvincent 0:05ccbd4f84f1 378 int
hendrikvincent 0:05ccbd4f84f1 379 dns_local_removehost(const char *hostname, const ip_addr_t *addr)
hendrikvincent 0:05ccbd4f84f1 380 {
hendrikvincent 0:05ccbd4f84f1 381 int removed = 0;
hendrikvincent 0:05ccbd4f84f1 382 struct local_hostlist_entry *entry = local_hostlist_dynamic;
hendrikvincent 0:05ccbd4f84f1 383 struct local_hostlist_entry *last_entry = NULL;
hendrikvincent 0:05ccbd4f84f1 384 while (entry != NULL) {
hendrikvincent 0:05ccbd4f84f1 385 if (((hostname == NULL) || !strcmp(entry->name, hostname)) &&
hendrikvincent 0:05ccbd4f84f1 386 ((addr == NULL) || ip_addr_cmp(&entry->addr, addr))) {
hendrikvincent 0:05ccbd4f84f1 387 struct local_hostlist_entry *free_entry;
hendrikvincent 0:05ccbd4f84f1 388 if (last_entry != NULL) {
hendrikvincent 0:05ccbd4f84f1 389 last_entry->next = entry->next;
hendrikvincent 0:05ccbd4f84f1 390 } else {
hendrikvincent 0:05ccbd4f84f1 391 local_hostlist_dynamic = entry->next;
hendrikvincent 0:05ccbd4f84f1 392 }
hendrikvincent 0:05ccbd4f84f1 393 free_entry = entry;
hendrikvincent 0:05ccbd4f84f1 394 entry = entry->next;
hendrikvincent 0:05ccbd4f84f1 395 memp_free(MEMP_LOCALHOSTLIST, free_entry);
hendrikvincent 0:05ccbd4f84f1 396 removed++;
hendrikvincent 0:05ccbd4f84f1 397 } else {
hendrikvincent 0:05ccbd4f84f1 398 last_entry = entry;
hendrikvincent 0:05ccbd4f84f1 399 entry = entry->next;
hendrikvincent 0:05ccbd4f84f1 400 }
hendrikvincent 0:05ccbd4f84f1 401 }
hendrikvincent 0:05ccbd4f84f1 402 return removed;
hendrikvincent 0:05ccbd4f84f1 403 }
hendrikvincent 0:05ccbd4f84f1 404
hendrikvincent 0:05ccbd4f84f1 405 /**
hendrikvincent 0:05ccbd4f84f1 406 * Add a hostname/IP address pair to the local host-list.
hendrikvincent 0:05ccbd4f84f1 407 * Duplicates are not checked.
hendrikvincent 0:05ccbd4f84f1 408 *
hendrikvincent 0:05ccbd4f84f1 409 * @param hostname hostname of the new entry
hendrikvincent 0:05ccbd4f84f1 410 * @param addr IP address of the new entry
hendrikvincent 0:05ccbd4f84f1 411 * @return ERR_OK if succeeded or ERR_MEM on memory error
hendrikvincent 0:05ccbd4f84f1 412 */
hendrikvincent 0:05ccbd4f84f1 413 err_t
hendrikvincent 0:05ccbd4f84f1 414 dns_local_addhost(const char *hostname, const ip_addr_t *addr)
hendrikvincent 0:05ccbd4f84f1 415 {
hendrikvincent 0:05ccbd4f84f1 416 struct local_hostlist_entry *entry;
hendrikvincent 0:05ccbd4f84f1 417 size_t namelen;
hendrikvincent 0:05ccbd4f84f1 418 LWIP_ASSERT("invalid host name (NULL)", hostname != NULL);
hendrikvincent 0:05ccbd4f84f1 419 namelen = strlen(hostname);
hendrikvincent 0:05ccbd4f84f1 420 LWIP_ASSERT("namelen <= DNS_LOCAL_HOSTLIST_MAX_NAMELEN", namelen <= DNS_LOCAL_HOSTLIST_MAX_NAMELEN);
hendrikvincent 0:05ccbd4f84f1 421 entry = (struct local_hostlist_entry *)memp_malloc(MEMP_LOCALHOSTLIST);
hendrikvincent 0:05ccbd4f84f1 422 if (entry == NULL) {
hendrikvincent 0:05ccbd4f84f1 423 return ERR_MEM;
hendrikvincent 0:05ccbd4f84f1 424 }
hendrikvincent 0:05ccbd4f84f1 425 entry->name = (char*)entry + sizeof(struct local_hostlist_entry);
hendrikvincent 0:05ccbd4f84f1 426 MEMCPY((char*)entry->name, hostname, namelen);
hendrikvincent 0:05ccbd4f84f1 427 ((char*)entry->name)[namelen] = 0;
hendrikvincent 0:05ccbd4f84f1 428 ip_addr_copy(entry->addr, *addr);
hendrikvincent 0:05ccbd4f84f1 429 entry->next = local_hostlist_dynamic;
hendrikvincent 0:05ccbd4f84f1 430 local_hostlist_dynamic = entry;
hendrikvincent 0:05ccbd4f84f1 431 return ERR_OK;
hendrikvincent 0:05ccbd4f84f1 432 }
hendrikvincent 0:05ccbd4f84f1 433 #endif /* DNS_LOCAL_HOSTLIST_IS_DYNAMIC*/
hendrikvincent 0:05ccbd4f84f1 434 #endif /* DNS_LOCAL_HOSTLIST */
hendrikvincent 0:05ccbd4f84f1 435
hendrikvincent 0:05ccbd4f84f1 436 /**
hendrikvincent 0:05ccbd4f84f1 437 * Look up a hostname in the array of known hostnames.
hendrikvincent 0:05ccbd4f84f1 438 *
hendrikvincent 0:05ccbd4f84f1 439 * @note This function only looks in the internal array of known
hendrikvincent 0:05ccbd4f84f1 440 * hostnames, it does not send out a query for the hostname if none
hendrikvincent 0:05ccbd4f84f1 441 * was found. The function dns_enqueue() can be used to send a query
hendrikvincent 0:05ccbd4f84f1 442 * for a hostname.
hendrikvincent 0:05ccbd4f84f1 443 *
hendrikvincent 0:05ccbd4f84f1 444 * @param name the hostname to look up
hendrikvincent 0:05ccbd4f84f1 445 * @return the hostname's IP address, as u32_t (instead of ip_addr_t to
hendrikvincent 0:05ccbd4f84f1 446 * better check for failure: != IPADDR_NONE) or IPADDR_NONE if the hostname
hendrikvincent 0:05ccbd4f84f1 447 * was not found in the cached dns_table.
hendrikvincent 0:05ccbd4f84f1 448 */
hendrikvincent 0:05ccbd4f84f1 449 static u32_t
hendrikvincent 0:05ccbd4f84f1 450 dns_lookup(const char *name)
hendrikvincent 0:05ccbd4f84f1 451 {
hendrikvincent 0:05ccbd4f84f1 452 u8_t i;
hendrikvincent 0:05ccbd4f84f1 453 #if DNS_LOCAL_HOSTLIST || defined(DNS_LOOKUP_LOCAL_EXTERN)
hendrikvincent 0:05ccbd4f84f1 454 u32_t addr;
hendrikvincent 0:05ccbd4f84f1 455 #endif /* DNS_LOCAL_HOSTLIST || defined(DNS_LOOKUP_LOCAL_EXTERN) */
hendrikvincent 0:05ccbd4f84f1 456 #if DNS_LOCAL_HOSTLIST
hendrikvincent 0:05ccbd4f84f1 457 if ((addr = dns_lookup_local(name)) != IPADDR_NONE) {
hendrikvincent 0:05ccbd4f84f1 458 return addr;
hendrikvincent 0:05ccbd4f84f1 459 }
hendrikvincent 0:05ccbd4f84f1 460 #endif /* DNS_LOCAL_HOSTLIST */
hendrikvincent 0:05ccbd4f84f1 461 #ifdef DNS_LOOKUP_LOCAL_EXTERN
hendrikvincent 0:05ccbd4f84f1 462 if((addr = DNS_LOOKUP_LOCAL_EXTERN(name)) != IPADDR_NONE) {
hendrikvincent 0:05ccbd4f84f1 463 return addr;
hendrikvincent 0:05ccbd4f84f1 464 }
hendrikvincent 0:05ccbd4f84f1 465 #endif /* DNS_LOOKUP_LOCAL_EXTERN */
hendrikvincent 0:05ccbd4f84f1 466
hendrikvincent 0:05ccbd4f84f1 467 /* Walk through name list, return entry if found. If not, return NULL. */
hendrikvincent 0:05ccbd4f84f1 468 for (i = 0; i < DNS_TABLE_SIZE; ++i) {
hendrikvincent 0:05ccbd4f84f1 469 if ((dns_table[i].state == DNS_STATE_DONE) &&
hendrikvincent 0:05ccbd4f84f1 470 (strcmp(name, dns_table[i].name) == 0)) {
hendrikvincent 0:05ccbd4f84f1 471 LWIP_DEBUGF(DNS_DEBUG, ("dns_lookup: \"%s\": found = ", name));
hendrikvincent 0:05ccbd4f84f1 472 ip_addr_debug_print(DNS_DEBUG, &(dns_table[i].ipaddr));
hendrikvincent 0:05ccbd4f84f1 473 LWIP_DEBUGF(DNS_DEBUG, ("\n"));
hendrikvincent 0:05ccbd4f84f1 474 return ip4_addr_get_u32(&dns_table[i].ipaddr);
hendrikvincent 0:05ccbd4f84f1 475 }
hendrikvincent 0:05ccbd4f84f1 476 }
hendrikvincent 0:05ccbd4f84f1 477
hendrikvincent 0:05ccbd4f84f1 478 return IPADDR_NONE;
hendrikvincent 0:05ccbd4f84f1 479 }
hendrikvincent 0:05ccbd4f84f1 480
hendrikvincent 0:05ccbd4f84f1 481 #if DNS_DOES_NAME_CHECK
hendrikvincent 0:05ccbd4f84f1 482 /**
hendrikvincent 0:05ccbd4f84f1 483 * Compare the "dotted" name "query" with the encoded name "response"
hendrikvincent 0:05ccbd4f84f1 484 * to make sure an answer from the DNS server matches the current dns_table
hendrikvincent 0:05ccbd4f84f1 485 * entry (otherwise, answers might arrive late for hostname not on the list
hendrikvincent 0:05ccbd4f84f1 486 * any more).
hendrikvincent 0:05ccbd4f84f1 487 *
hendrikvincent 0:05ccbd4f84f1 488 * @param query hostname (not encoded) from the dns_table
hendrikvincent 0:05ccbd4f84f1 489 * @param response encoded hostname in the DNS response
hendrikvincent 0:05ccbd4f84f1 490 * @return 0: names equal; 1: names differ
hendrikvincent 0:05ccbd4f84f1 491 */
hendrikvincent 0:05ccbd4f84f1 492 static u8_t
hendrikvincent 0:05ccbd4f84f1 493 dns_compare_name(unsigned char *query, unsigned char *response)
hendrikvincent 0:05ccbd4f84f1 494 {
hendrikvincent 0:05ccbd4f84f1 495 unsigned char n;
hendrikvincent 0:05ccbd4f84f1 496
hendrikvincent 0:05ccbd4f84f1 497 do {
hendrikvincent 0:05ccbd4f84f1 498 n = *response++;
hendrikvincent 0:05ccbd4f84f1 499 /** @see RFC 1035 - 4.1.4. Message compression */
hendrikvincent 0:05ccbd4f84f1 500 if ((n & 0xc0) == 0xc0) {
hendrikvincent 0:05ccbd4f84f1 501 /* Compressed name */
hendrikvincent 0:05ccbd4f84f1 502 break;
hendrikvincent 0:05ccbd4f84f1 503 } else {
hendrikvincent 0:05ccbd4f84f1 504 /* Not compressed name */
hendrikvincent 0:05ccbd4f84f1 505 while (n > 0) {
hendrikvincent 0:05ccbd4f84f1 506 if ((*query) != (*response)) {
hendrikvincent 0:05ccbd4f84f1 507 return 1;
hendrikvincent 0:05ccbd4f84f1 508 }
hendrikvincent 0:05ccbd4f84f1 509 ++response;
hendrikvincent 0:05ccbd4f84f1 510 ++query;
hendrikvincent 0:05ccbd4f84f1 511 --n;
hendrikvincent 0:05ccbd4f84f1 512 };
hendrikvincent 0:05ccbd4f84f1 513 ++query;
hendrikvincent 0:05ccbd4f84f1 514 }
hendrikvincent 0:05ccbd4f84f1 515 } while (*response != 0);
hendrikvincent 0:05ccbd4f84f1 516
hendrikvincent 0:05ccbd4f84f1 517 return 0;
hendrikvincent 0:05ccbd4f84f1 518 }
hendrikvincent 0:05ccbd4f84f1 519 #endif /* DNS_DOES_NAME_CHECK */
hendrikvincent 0:05ccbd4f84f1 520
hendrikvincent 0:05ccbd4f84f1 521 /**
hendrikvincent 0:05ccbd4f84f1 522 * Walk through a compact encoded DNS name and return the end of the name.
hendrikvincent 0:05ccbd4f84f1 523 *
hendrikvincent 0:05ccbd4f84f1 524 * @param query encoded DNS name in the DNS server response
hendrikvincent 0:05ccbd4f84f1 525 * @return end of the name
hendrikvincent 0:05ccbd4f84f1 526 */
hendrikvincent 0:05ccbd4f84f1 527 static unsigned char *
hendrikvincent 0:05ccbd4f84f1 528 dns_parse_name(unsigned char *query)
hendrikvincent 0:05ccbd4f84f1 529 {
hendrikvincent 0:05ccbd4f84f1 530 unsigned char n;
hendrikvincent 0:05ccbd4f84f1 531
hendrikvincent 0:05ccbd4f84f1 532 do {
hendrikvincent 0:05ccbd4f84f1 533 n = *query++;
hendrikvincent 0:05ccbd4f84f1 534 /** @see RFC 1035 - 4.1.4. Message compression */
hendrikvincent 0:05ccbd4f84f1 535 if ((n & 0xc0) == 0xc0) {
hendrikvincent 0:05ccbd4f84f1 536 /* Compressed name */
hendrikvincent 0:05ccbd4f84f1 537 break;
hendrikvincent 0:05ccbd4f84f1 538 } else {
hendrikvincent 0:05ccbd4f84f1 539 /* Not compressed name */
hendrikvincent 0:05ccbd4f84f1 540 while (n > 0) {
hendrikvincent 0:05ccbd4f84f1 541 ++query;
hendrikvincent 0:05ccbd4f84f1 542 --n;
hendrikvincent 0:05ccbd4f84f1 543 };
hendrikvincent 0:05ccbd4f84f1 544 }
hendrikvincent 0:05ccbd4f84f1 545 } while (*query != 0);
hendrikvincent 0:05ccbd4f84f1 546
hendrikvincent 0:05ccbd4f84f1 547 return query + 1;
hendrikvincent 0:05ccbd4f84f1 548 }
hendrikvincent 0:05ccbd4f84f1 549
hendrikvincent 0:05ccbd4f84f1 550 /**
hendrikvincent 0:05ccbd4f84f1 551 * Send a DNS query packet.
hendrikvincent 0:05ccbd4f84f1 552 *
hendrikvincent 0:05ccbd4f84f1 553 * @param numdns index of the DNS server in the dns_servers table
hendrikvincent 0:05ccbd4f84f1 554 * @param name hostname to query
hendrikvincent 0:05ccbd4f84f1 555 * @param id index of the hostname in dns_table, used as transaction ID in the
hendrikvincent 0:05ccbd4f84f1 556 * DNS query packet
hendrikvincent 0:05ccbd4f84f1 557 * @return ERR_OK if packet is sent; an err_t indicating the problem otherwise
hendrikvincent 0:05ccbd4f84f1 558 */
hendrikvincent 0:05ccbd4f84f1 559 static err_t
hendrikvincent 0:05ccbd4f84f1 560 dns_send(u8_t numdns, const char* name, u8_t id)
hendrikvincent 0:05ccbd4f84f1 561 {
hendrikvincent 0:05ccbd4f84f1 562 err_t err;
hendrikvincent 0:05ccbd4f84f1 563 struct dns_hdr *hdr;
hendrikvincent 0:05ccbd4f84f1 564 struct dns_query qry;
hendrikvincent 0:05ccbd4f84f1 565 struct pbuf *p;
hendrikvincent 0:05ccbd4f84f1 566 char *query, *nptr;
hendrikvincent 0:05ccbd4f84f1 567 const char *pHostname;
hendrikvincent 0:05ccbd4f84f1 568 u8_t n;
hendrikvincent 0:05ccbd4f84f1 569
hendrikvincent 0:05ccbd4f84f1 570 LWIP_DEBUGF(DNS_DEBUG, ("dns_send: dns_servers[%"U16_F"] \"%s\": request\n",
hendrikvincent 0:05ccbd4f84f1 571 (u16_t)(numdns), name));
hendrikvincent 0:05ccbd4f84f1 572 LWIP_ASSERT("dns server out of array", numdns < DNS_MAX_SERVERS);
hendrikvincent 0:05ccbd4f84f1 573 LWIP_ASSERT("dns server has no IP address set", !ip_addr_isany(&dns_servers[numdns]));
hendrikvincent 0:05ccbd4f84f1 574
hendrikvincent 0:05ccbd4f84f1 575 /* if here, we have either a new query or a retry on a previous query to process */
hendrikvincent 0:05ccbd4f84f1 576 p = pbuf_alloc(PBUF_TRANSPORT, SIZEOF_DNS_HDR + DNS_MAX_NAME_LENGTH +
hendrikvincent 0:05ccbd4f84f1 577 SIZEOF_DNS_QUERY, PBUF_RAM);
hendrikvincent 0:05ccbd4f84f1 578 if (p != NULL) {
hendrikvincent 0:05ccbd4f84f1 579 LWIP_ASSERT("pbuf must be in one piece", p->next == NULL);
hendrikvincent 0:05ccbd4f84f1 580 /* fill dns header */
hendrikvincent 0:05ccbd4f84f1 581 hdr = (struct dns_hdr*)p->payload;
hendrikvincent 0:05ccbd4f84f1 582 memset(hdr, 0, SIZEOF_DNS_HDR);
hendrikvincent 0:05ccbd4f84f1 583 hdr->id = htons(id);
hendrikvincent 0:05ccbd4f84f1 584 hdr->flags1 = DNS_FLAG1_RD;
hendrikvincent 0:05ccbd4f84f1 585 hdr->numquestions = PP_HTONS(1);
hendrikvincent 0:05ccbd4f84f1 586 query = (char*)hdr + SIZEOF_DNS_HDR;
hendrikvincent 0:05ccbd4f84f1 587 pHostname = name;
hendrikvincent 0:05ccbd4f84f1 588 --pHostname;
hendrikvincent 0:05ccbd4f84f1 589
hendrikvincent 0:05ccbd4f84f1 590 /* convert hostname into suitable query format. */
hendrikvincent 0:05ccbd4f84f1 591 do {
hendrikvincent 0:05ccbd4f84f1 592 ++pHostname;
hendrikvincent 0:05ccbd4f84f1 593 nptr = query;
hendrikvincent 0:05ccbd4f84f1 594 ++query;
hendrikvincent 0:05ccbd4f84f1 595 for(n = 0; *pHostname != '.' && *pHostname != 0; ++pHostname) {
hendrikvincent 0:05ccbd4f84f1 596 *query = *pHostname;
hendrikvincent 0:05ccbd4f84f1 597 ++query;
hendrikvincent 0:05ccbd4f84f1 598 ++n;
hendrikvincent 0:05ccbd4f84f1 599 }
hendrikvincent 0:05ccbd4f84f1 600 *nptr = n;
hendrikvincent 0:05ccbd4f84f1 601 } while(*pHostname != 0);
hendrikvincent 0:05ccbd4f84f1 602 *query++='\0';
hendrikvincent 0:05ccbd4f84f1 603
hendrikvincent 0:05ccbd4f84f1 604 /* fill dns query */
hendrikvincent 0:05ccbd4f84f1 605 qry.type = PP_HTONS(DNS_RRTYPE_A);
hendrikvincent 0:05ccbd4f84f1 606 qry.cls = PP_HTONS(DNS_RRCLASS_IN);
hendrikvincent 0:05ccbd4f84f1 607 SMEMCPY(query, &qry, SIZEOF_DNS_QUERY);
hendrikvincent 0:05ccbd4f84f1 608
hendrikvincent 0:05ccbd4f84f1 609 /* resize pbuf to the exact dns query */
hendrikvincent 0:05ccbd4f84f1 610 pbuf_realloc(p, (u16_t)((query + SIZEOF_DNS_QUERY) - ((char*)(p->payload))));
hendrikvincent 0:05ccbd4f84f1 611
hendrikvincent 0:05ccbd4f84f1 612 /* connect to the server for faster receiving */
hendrikvincent 0:05ccbd4f84f1 613 udp_connect(dns_pcb, &dns_servers[numdns], DNS_SERVER_PORT);
hendrikvincent 0:05ccbd4f84f1 614 /* send dns packet */
hendrikvincent 0:05ccbd4f84f1 615 err = udp_sendto(dns_pcb, p, &dns_servers[numdns], DNS_SERVER_PORT);
hendrikvincent 0:05ccbd4f84f1 616
hendrikvincent 0:05ccbd4f84f1 617 /* free pbuf */
hendrikvincent 0:05ccbd4f84f1 618 pbuf_free(p);
hendrikvincent 0:05ccbd4f84f1 619 } else {
hendrikvincent 0:05ccbd4f84f1 620 err = ERR_MEM;
hendrikvincent 0:05ccbd4f84f1 621 }
hendrikvincent 0:05ccbd4f84f1 622
hendrikvincent 0:05ccbd4f84f1 623 return err;
hendrikvincent 0:05ccbd4f84f1 624 }
hendrikvincent 0:05ccbd4f84f1 625
hendrikvincent 0:05ccbd4f84f1 626 /**
hendrikvincent 0:05ccbd4f84f1 627 * dns_check_entry() - see if pEntry has not yet been queried and, if so, sends out a query.
hendrikvincent 0:05ccbd4f84f1 628 * Check an entry in the dns_table:
hendrikvincent 0:05ccbd4f84f1 629 * - send out query for new entries
hendrikvincent 0:05ccbd4f84f1 630 * - retry old pending entries on timeout (also with different servers)
hendrikvincent 0:05ccbd4f84f1 631 * - remove completed entries from the table if their TTL has expired
hendrikvincent 0:05ccbd4f84f1 632 *
hendrikvincent 0:05ccbd4f84f1 633 * @param i index of the dns_table entry to check
hendrikvincent 0:05ccbd4f84f1 634 */
hendrikvincent 0:05ccbd4f84f1 635 static void
hendrikvincent 0:05ccbd4f84f1 636 dns_check_entry(u8_t i)
hendrikvincent 0:05ccbd4f84f1 637 {
hendrikvincent 0:05ccbd4f84f1 638 err_t err;
hendrikvincent 0:05ccbd4f84f1 639 struct dns_table_entry *pEntry = &dns_table[i];
hendrikvincent 0:05ccbd4f84f1 640
hendrikvincent 0:05ccbd4f84f1 641 LWIP_ASSERT("array index out of bounds", i < DNS_TABLE_SIZE);
hendrikvincent 0:05ccbd4f84f1 642
hendrikvincent 0:05ccbd4f84f1 643 switch(pEntry->state) {
hendrikvincent 0:05ccbd4f84f1 644
hendrikvincent 0:05ccbd4f84f1 645 case DNS_STATE_NEW: {
hendrikvincent 0:05ccbd4f84f1 646 /* initialize new entry */
hendrikvincent 0:05ccbd4f84f1 647 pEntry->state = DNS_STATE_ASKING;
hendrikvincent 0:05ccbd4f84f1 648 pEntry->numdns = 0;
hendrikvincent 0:05ccbd4f84f1 649 pEntry->tmr = 1;
hendrikvincent 0:05ccbd4f84f1 650 pEntry->retries = 0;
hendrikvincent 0:05ccbd4f84f1 651
hendrikvincent 0:05ccbd4f84f1 652 /* send DNS packet for this entry */
hendrikvincent 0:05ccbd4f84f1 653 err = dns_send(pEntry->numdns, pEntry->name, i);
hendrikvincent 0:05ccbd4f84f1 654 if (err != ERR_OK) {
hendrikvincent 0:05ccbd4f84f1 655 LWIP_DEBUGF(DNS_DEBUG | LWIP_DBG_LEVEL_WARNING,
hendrikvincent 0:05ccbd4f84f1 656 ("dns_send returned error: %d\n", err)); //FIX DG, lwip_strerr is part of lwip/api
hendrikvincent 0:05ccbd4f84f1 657 }
hendrikvincent 0:05ccbd4f84f1 658 break;
hendrikvincent 0:05ccbd4f84f1 659 }
hendrikvincent 0:05ccbd4f84f1 660
hendrikvincent 0:05ccbd4f84f1 661 case DNS_STATE_ASKING: {
hendrikvincent 0:05ccbd4f84f1 662 if (--pEntry->tmr == 0) {
hendrikvincent 0:05ccbd4f84f1 663 if (++pEntry->retries == DNS_MAX_RETRIES) {
hendrikvincent 0:05ccbd4f84f1 664 if ((pEntry->numdns+1<DNS_MAX_SERVERS) && !ip_addr_isany(&dns_servers[pEntry->numdns+1])) {
hendrikvincent 0:05ccbd4f84f1 665 /* change of server */
hendrikvincent 0:05ccbd4f84f1 666 pEntry->numdns++;
hendrikvincent 0:05ccbd4f84f1 667 pEntry->tmr = 1;
hendrikvincent 0:05ccbd4f84f1 668 pEntry->retries = 0;
hendrikvincent 0:05ccbd4f84f1 669 break;
hendrikvincent 0:05ccbd4f84f1 670 } else {
hendrikvincent 0:05ccbd4f84f1 671 LWIP_DEBUGF(DNS_DEBUG, ("dns_check_entry: \"%s\": timeout\n", pEntry->name));
hendrikvincent 0:05ccbd4f84f1 672 /* call specified callback function if provided */
hendrikvincent 0:05ccbd4f84f1 673 if (pEntry->found)
hendrikvincent 0:05ccbd4f84f1 674 (*pEntry->found)(pEntry->name, NULL, pEntry->arg);
hendrikvincent 0:05ccbd4f84f1 675 /* flush this entry */
hendrikvincent 0:05ccbd4f84f1 676 pEntry->state = DNS_STATE_UNUSED;
hendrikvincent 0:05ccbd4f84f1 677 pEntry->found = NULL;
hendrikvincent 0:05ccbd4f84f1 678 break;
hendrikvincent 0:05ccbd4f84f1 679 }
hendrikvincent 0:05ccbd4f84f1 680 }
hendrikvincent 0:05ccbd4f84f1 681
hendrikvincent 0:05ccbd4f84f1 682 /* wait longer for the next retry */
hendrikvincent 0:05ccbd4f84f1 683 pEntry->tmr = pEntry->retries;
hendrikvincent 0:05ccbd4f84f1 684
hendrikvincent 0:05ccbd4f84f1 685 /* send DNS packet for this entry */
hendrikvincent 0:05ccbd4f84f1 686 err = dns_send(pEntry->numdns, pEntry->name, i);
hendrikvincent 0:05ccbd4f84f1 687 if (err != ERR_OK) {
hendrikvincent 0:05ccbd4f84f1 688 LWIP_DEBUGF(DNS_DEBUG | LWIP_DBG_LEVEL_WARNING,
hendrikvincent 0:05ccbd4f84f1 689 ("dns_send returned error: %d\n", err)); //FIX DG, lwip_strerr is part of lwip/api
hendrikvincent 0:05ccbd4f84f1 690 }
hendrikvincent 0:05ccbd4f84f1 691 }
hendrikvincent 0:05ccbd4f84f1 692 break;
hendrikvincent 0:05ccbd4f84f1 693 }
hendrikvincent 0:05ccbd4f84f1 694
hendrikvincent 0:05ccbd4f84f1 695 case DNS_STATE_DONE: {
hendrikvincent 0:05ccbd4f84f1 696 /* if the time to live is nul */
hendrikvincent 0:05ccbd4f84f1 697 if (--pEntry->ttl == 0) {
hendrikvincent 0:05ccbd4f84f1 698 LWIP_DEBUGF(DNS_DEBUG, ("dns_check_entry: \"%s\": flush\n", pEntry->name));
hendrikvincent 0:05ccbd4f84f1 699 /* flush this entry */
hendrikvincent 0:05ccbd4f84f1 700 pEntry->state = DNS_STATE_UNUSED;
hendrikvincent 0:05ccbd4f84f1 701 pEntry->found = NULL;
hendrikvincent 0:05ccbd4f84f1 702 }
hendrikvincent 0:05ccbd4f84f1 703 break;
hendrikvincent 0:05ccbd4f84f1 704 }
hendrikvincent 0:05ccbd4f84f1 705 case DNS_STATE_UNUSED:
hendrikvincent 0:05ccbd4f84f1 706 /* nothing to do */
hendrikvincent 0:05ccbd4f84f1 707 break;
hendrikvincent 0:05ccbd4f84f1 708 default:
hendrikvincent 0:05ccbd4f84f1 709 LWIP_ASSERT("unknown dns_table entry state:", 0);
hendrikvincent 0:05ccbd4f84f1 710 break;
hendrikvincent 0:05ccbd4f84f1 711 }
hendrikvincent 0:05ccbd4f84f1 712 }
hendrikvincent 0:05ccbd4f84f1 713
hendrikvincent 0:05ccbd4f84f1 714 /**
hendrikvincent 0:05ccbd4f84f1 715 * Call dns_check_entry for each entry in dns_table - check all entries.
hendrikvincent 0:05ccbd4f84f1 716 */
hendrikvincent 0:05ccbd4f84f1 717 static void
hendrikvincent 0:05ccbd4f84f1 718 dns_check_entries(void)
hendrikvincent 0:05ccbd4f84f1 719 {
hendrikvincent 0:05ccbd4f84f1 720 u8_t i;
hendrikvincent 0:05ccbd4f84f1 721
hendrikvincent 0:05ccbd4f84f1 722 for (i = 0; i < DNS_TABLE_SIZE; ++i) {
hendrikvincent 0:05ccbd4f84f1 723 dns_check_entry(i);
hendrikvincent 0:05ccbd4f84f1 724 }
hendrikvincent 0:05ccbd4f84f1 725 }
hendrikvincent 0:05ccbd4f84f1 726
hendrikvincent 0:05ccbd4f84f1 727 /**
hendrikvincent 0:05ccbd4f84f1 728 * Receive input function for DNS response packets arriving for the dns UDP pcb.
hendrikvincent 0:05ccbd4f84f1 729 *
hendrikvincent 0:05ccbd4f84f1 730 * @params see udp.h
hendrikvincent 0:05ccbd4f84f1 731 */
hendrikvincent 0:05ccbd4f84f1 732 static void
hendrikvincent 0:05ccbd4f84f1 733 dns_recv(void *arg, struct udp_pcb *pcb, struct pbuf *p, ip_addr_t *addr, u16_t port)
hendrikvincent 0:05ccbd4f84f1 734 {
hendrikvincent 0:05ccbd4f84f1 735 u16_t i;
hendrikvincent 0:05ccbd4f84f1 736 char *pHostname;
hendrikvincent 0:05ccbd4f84f1 737 struct dns_hdr *hdr;
hendrikvincent 0:05ccbd4f84f1 738 struct dns_answer ans;
hendrikvincent 0:05ccbd4f84f1 739 struct dns_table_entry *pEntry;
hendrikvincent 0:05ccbd4f84f1 740 u16_t nquestions, nanswers;
hendrikvincent 0:05ccbd4f84f1 741
hendrikvincent 0:05ccbd4f84f1 742 LWIP_UNUSED_ARG(arg);
hendrikvincent 0:05ccbd4f84f1 743 LWIP_UNUSED_ARG(pcb);
hendrikvincent 0:05ccbd4f84f1 744 LWIP_UNUSED_ARG(addr);
hendrikvincent 0:05ccbd4f84f1 745 LWIP_UNUSED_ARG(port);
hendrikvincent 0:05ccbd4f84f1 746
hendrikvincent 0:05ccbd4f84f1 747 /* is the dns message too big ? */
hendrikvincent 0:05ccbd4f84f1 748 if (p->tot_len > DNS_MSG_SIZE) {
hendrikvincent 0:05ccbd4f84f1 749 LWIP_DEBUGF(DNS_DEBUG, ("dns_recv: pbuf too big\n"));
hendrikvincent 0:05ccbd4f84f1 750 /* free pbuf and return */
hendrikvincent 0:05ccbd4f84f1 751 goto memerr;
hendrikvincent 0:05ccbd4f84f1 752 }
hendrikvincent 0:05ccbd4f84f1 753
hendrikvincent 0:05ccbd4f84f1 754 /* is the dns message big enough ? */
hendrikvincent 0:05ccbd4f84f1 755 if (p->tot_len < (SIZEOF_DNS_HDR + SIZEOF_DNS_QUERY + SIZEOF_DNS_ANSWER)) {
hendrikvincent 0:05ccbd4f84f1 756 LWIP_DEBUGF(DNS_DEBUG, ("dns_recv: pbuf too small\n"));
hendrikvincent 0:05ccbd4f84f1 757 /* free pbuf and return */
hendrikvincent 0:05ccbd4f84f1 758 goto memerr;
hendrikvincent 0:05ccbd4f84f1 759 }
hendrikvincent 0:05ccbd4f84f1 760
hendrikvincent 0:05ccbd4f84f1 761 /* copy dns payload inside static buffer for processing */
hendrikvincent 0:05ccbd4f84f1 762 if (pbuf_copy_partial(p, dns_payload, p->tot_len, 0) == p->tot_len) {
hendrikvincent 0:05ccbd4f84f1 763 /* The ID in the DNS header should be our entry into the name table. */
hendrikvincent 0:05ccbd4f84f1 764 hdr = (struct dns_hdr*)dns_payload;
hendrikvincent 0:05ccbd4f84f1 765 i = htons(hdr->id);
hendrikvincent 0:05ccbd4f84f1 766 if (i < DNS_TABLE_SIZE) {
hendrikvincent 0:05ccbd4f84f1 767 pEntry = &dns_table[i];
hendrikvincent 0:05ccbd4f84f1 768 if(pEntry->state == DNS_STATE_ASKING) {
hendrikvincent 0:05ccbd4f84f1 769 /* This entry is now completed. */
hendrikvincent 0:05ccbd4f84f1 770 pEntry->state = DNS_STATE_DONE;
hendrikvincent 0:05ccbd4f84f1 771 pEntry->err = hdr->flags2 & DNS_FLAG2_ERR_MASK;
hendrikvincent 0:05ccbd4f84f1 772
hendrikvincent 0:05ccbd4f84f1 773 /* We only care about the question(s) and the answers. The authrr
hendrikvincent 0:05ccbd4f84f1 774 and the extrarr are simply discarded. */
hendrikvincent 0:05ccbd4f84f1 775 nquestions = htons(hdr->numquestions);
hendrikvincent 0:05ccbd4f84f1 776 nanswers = htons(hdr->numanswers);
hendrikvincent 0:05ccbd4f84f1 777
hendrikvincent 0:05ccbd4f84f1 778 /* Check for error. If so, call callback to inform. */
hendrikvincent 0:05ccbd4f84f1 779 if (((hdr->flags1 & DNS_FLAG1_RESPONSE) == 0) || (pEntry->err != 0) || (nquestions != 1)) {
hendrikvincent 0:05ccbd4f84f1 780 LWIP_DEBUGF(DNS_DEBUG, ("dns_recv: \"%s\": error in flags\n", pEntry->name));
hendrikvincent 0:05ccbd4f84f1 781 /* call callback to indicate error, clean up memory and return */
hendrikvincent 0:05ccbd4f84f1 782 goto responseerr;
hendrikvincent 0:05ccbd4f84f1 783 }
hendrikvincent 0:05ccbd4f84f1 784
hendrikvincent 0:05ccbd4f84f1 785 #if DNS_DOES_NAME_CHECK
hendrikvincent 0:05ccbd4f84f1 786 /* Check if the name in the "question" part match with the name in the entry. */
hendrikvincent 0:05ccbd4f84f1 787 if (dns_compare_name((unsigned char *)(pEntry->name), (unsigned char *)dns_payload + SIZEOF_DNS_HDR) != 0) {
hendrikvincent 0:05ccbd4f84f1 788 LWIP_DEBUGF(DNS_DEBUG, ("dns_recv: \"%s\": response not match to query\n", pEntry->name));
hendrikvincent 0:05ccbd4f84f1 789 /* call callback to indicate error, clean up memory and return */
hendrikvincent 0:05ccbd4f84f1 790 goto responseerr;
hendrikvincent 0:05ccbd4f84f1 791 }
hendrikvincent 0:05ccbd4f84f1 792 #endif /* DNS_DOES_NAME_CHECK */
hendrikvincent 0:05ccbd4f84f1 793
hendrikvincent 0:05ccbd4f84f1 794 /* Skip the name in the "question" part */
hendrikvincent 0:05ccbd4f84f1 795 pHostname = (char *) dns_parse_name((unsigned char *)dns_payload + SIZEOF_DNS_HDR) + SIZEOF_DNS_QUERY;
hendrikvincent 0:05ccbd4f84f1 796
hendrikvincent 0:05ccbd4f84f1 797 while (nanswers > 0) {
hendrikvincent 0:05ccbd4f84f1 798 /* skip answer resource record's host name */
hendrikvincent 0:05ccbd4f84f1 799 pHostname = (char *) dns_parse_name((unsigned char *)pHostname);
hendrikvincent 0:05ccbd4f84f1 800
hendrikvincent 0:05ccbd4f84f1 801 /* Check for IP address type and Internet class. Others are discarded. */
hendrikvincent 0:05ccbd4f84f1 802 SMEMCPY(&ans, pHostname, SIZEOF_DNS_ANSWER);
hendrikvincent 0:05ccbd4f84f1 803 if((ans.type == PP_HTONS(DNS_RRTYPE_A)) && (ans.cls == PP_HTONS(DNS_RRCLASS_IN)) &&
hendrikvincent 0:05ccbd4f84f1 804 (ans.len == PP_HTONS(sizeof(ip_addr_t))) ) {
hendrikvincent 0:05ccbd4f84f1 805 /* read the answer resource record's TTL, and maximize it if needed */
hendrikvincent 0:05ccbd4f84f1 806 pEntry->ttl = ntohl(ans.ttl);
hendrikvincent 0:05ccbd4f84f1 807 if (pEntry->ttl > DNS_MAX_TTL) {
hendrikvincent 0:05ccbd4f84f1 808 pEntry->ttl = DNS_MAX_TTL;
hendrikvincent 0:05ccbd4f84f1 809 }
hendrikvincent 0:05ccbd4f84f1 810 /* read the IP address after answer resource record's header */
hendrikvincent 0:05ccbd4f84f1 811 SMEMCPY(&(pEntry->ipaddr), (pHostname+SIZEOF_DNS_ANSWER), sizeof(ip_addr_t));
hendrikvincent 0:05ccbd4f84f1 812 LWIP_DEBUGF(DNS_DEBUG, ("dns_recv: \"%s\": response = ", pEntry->name));
hendrikvincent 0:05ccbd4f84f1 813 ip_addr_debug_print(DNS_DEBUG, (&(pEntry->ipaddr)));
hendrikvincent 0:05ccbd4f84f1 814 LWIP_DEBUGF(DNS_DEBUG, ("\n"));
hendrikvincent 0:05ccbd4f84f1 815 /* call specified callback function if provided */
hendrikvincent 0:05ccbd4f84f1 816 if (pEntry->found) {
hendrikvincent 0:05ccbd4f84f1 817 (*pEntry->found)(pEntry->name, &pEntry->ipaddr, pEntry->arg);
hendrikvincent 0:05ccbd4f84f1 818 }
hendrikvincent 0:05ccbd4f84f1 819 /* deallocate memory and return */
hendrikvincent 0:05ccbd4f84f1 820 goto memerr;
hendrikvincent 0:05ccbd4f84f1 821 } else {
hendrikvincent 0:05ccbd4f84f1 822 pHostname = pHostname + SIZEOF_DNS_ANSWER + htons(ans.len);
hendrikvincent 0:05ccbd4f84f1 823 }
hendrikvincent 0:05ccbd4f84f1 824 --nanswers;
hendrikvincent 0:05ccbd4f84f1 825 }
hendrikvincent 0:05ccbd4f84f1 826 LWIP_DEBUGF(DNS_DEBUG, ("dns_recv: \"%s\": error in response\n", pEntry->name));
hendrikvincent 0:05ccbd4f84f1 827 /* call callback to indicate error, clean up memory and return */
hendrikvincent 0:05ccbd4f84f1 828 goto responseerr;
hendrikvincent 0:05ccbd4f84f1 829 }
hendrikvincent 0:05ccbd4f84f1 830 }
hendrikvincent 0:05ccbd4f84f1 831 }
hendrikvincent 0:05ccbd4f84f1 832
hendrikvincent 0:05ccbd4f84f1 833 /* deallocate memory and return */
hendrikvincent 0:05ccbd4f84f1 834 goto memerr;
hendrikvincent 0:05ccbd4f84f1 835
hendrikvincent 0:05ccbd4f84f1 836 responseerr:
hendrikvincent 0:05ccbd4f84f1 837 /* ERROR: call specified callback function with NULL as name to indicate an error */
hendrikvincent 0:05ccbd4f84f1 838 if (pEntry->found) {
hendrikvincent 0:05ccbd4f84f1 839 (*pEntry->found)(pEntry->name, NULL, pEntry->arg);
hendrikvincent 0:05ccbd4f84f1 840 }
hendrikvincent 0:05ccbd4f84f1 841 /* flush this entry */
hendrikvincent 0:05ccbd4f84f1 842 pEntry->state = DNS_STATE_UNUSED;
hendrikvincent 0:05ccbd4f84f1 843 pEntry->found = NULL;
hendrikvincent 0:05ccbd4f84f1 844
hendrikvincent 0:05ccbd4f84f1 845 memerr:
hendrikvincent 0:05ccbd4f84f1 846 /* free pbuf */
hendrikvincent 0:05ccbd4f84f1 847 pbuf_free(p);
hendrikvincent 0:05ccbd4f84f1 848 return;
hendrikvincent 0:05ccbd4f84f1 849 }
hendrikvincent 0:05ccbd4f84f1 850
hendrikvincent 0:05ccbd4f84f1 851 /**
hendrikvincent 0:05ccbd4f84f1 852 * Queues a new hostname to resolve and sends out a DNS query for that hostname
hendrikvincent 0:05ccbd4f84f1 853 *
hendrikvincent 0:05ccbd4f84f1 854 * @param name the hostname that is to be queried
hendrikvincent 0:05ccbd4f84f1 855 * @param found a callback founction to be called on success, failure or timeout
hendrikvincent 0:05ccbd4f84f1 856 * @param callback_arg argument to pass to the callback function
hendrikvincent 0:05ccbd4f84f1 857 * @return @return a err_t return code.
hendrikvincent 0:05ccbd4f84f1 858 */
hendrikvincent 0:05ccbd4f84f1 859 static err_t
hendrikvincent 0:05ccbd4f84f1 860 dns_enqueue(const char *name, dns_found_callback found, void *callback_arg)
hendrikvincent 0:05ccbd4f84f1 861 {
hendrikvincent 0:05ccbd4f84f1 862 u8_t i;
hendrikvincent 0:05ccbd4f84f1 863 u8_t lseq, lseqi;
hendrikvincent 0:05ccbd4f84f1 864 struct dns_table_entry *pEntry = NULL;
hendrikvincent 0:05ccbd4f84f1 865 size_t namelen;
hendrikvincent 0:05ccbd4f84f1 866
hendrikvincent 0:05ccbd4f84f1 867 /* search an unused entry, or the oldest one */
hendrikvincent 0:05ccbd4f84f1 868 lseq = lseqi = 0;
hendrikvincent 0:05ccbd4f84f1 869 for (i = 0; i < DNS_TABLE_SIZE; ++i) {
hendrikvincent 0:05ccbd4f84f1 870 pEntry = &dns_table[i];
hendrikvincent 0:05ccbd4f84f1 871 /* is it an unused entry ? */
hendrikvincent 0:05ccbd4f84f1 872 if (pEntry->state == DNS_STATE_UNUSED)
hendrikvincent 0:05ccbd4f84f1 873 break;
hendrikvincent 0:05ccbd4f84f1 874
hendrikvincent 0:05ccbd4f84f1 875 /* check if this is the oldest completed entry */
hendrikvincent 0:05ccbd4f84f1 876 if (pEntry->state == DNS_STATE_DONE) {
hendrikvincent 0:05ccbd4f84f1 877 if ((dns_seqno - pEntry->seqno) > lseq) {
hendrikvincent 0:05ccbd4f84f1 878 lseq = dns_seqno - pEntry->seqno;
hendrikvincent 0:05ccbd4f84f1 879 lseqi = i;
hendrikvincent 0:05ccbd4f84f1 880 }
hendrikvincent 0:05ccbd4f84f1 881 }
hendrikvincent 0:05ccbd4f84f1 882 }
hendrikvincent 0:05ccbd4f84f1 883
hendrikvincent 0:05ccbd4f84f1 884 /* if we don't have found an unused entry, use the oldest completed one */
hendrikvincent 0:05ccbd4f84f1 885 if (i == DNS_TABLE_SIZE) {
hendrikvincent 0:05ccbd4f84f1 886 if ((lseqi >= DNS_TABLE_SIZE) || (dns_table[lseqi].state != DNS_STATE_DONE)) {
hendrikvincent 0:05ccbd4f84f1 887 /* no entry can't be used now, table is full */
hendrikvincent 0:05ccbd4f84f1 888 LWIP_DEBUGF(DNS_DEBUG, ("dns_enqueue: \"%s\": DNS entries table is full\n", name));
hendrikvincent 0:05ccbd4f84f1 889 return ERR_MEM;
hendrikvincent 0:05ccbd4f84f1 890 } else {
hendrikvincent 0:05ccbd4f84f1 891 /* use the oldest completed one */
hendrikvincent 0:05ccbd4f84f1 892 i = lseqi;
hendrikvincent 0:05ccbd4f84f1 893 pEntry = &dns_table[i];
hendrikvincent 0:05ccbd4f84f1 894 }
hendrikvincent 0:05ccbd4f84f1 895 }
hendrikvincent 0:05ccbd4f84f1 896
hendrikvincent 0:05ccbd4f84f1 897 /* use this entry */
hendrikvincent 0:05ccbd4f84f1 898 LWIP_DEBUGF(DNS_DEBUG, ("dns_enqueue: \"%s\": use DNS entry %"U16_F"\n", name, (u16_t)(i)));
hendrikvincent 0:05ccbd4f84f1 899
hendrikvincent 0:05ccbd4f84f1 900 /* fill the entry */
hendrikvincent 0:05ccbd4f84f1 901 pEntry->state = DNS_STATE_NEW;
hendrikvincent 0:05ccbd4f84f1 902 pEntry->seqno = dns_seqno++;
hendrikvincent 0:05ccbd4f84f1 903 pEntry->found = found;
hendrikvincent 0:05ccbd4f84f1 904 pEntry->arg = callback_arg;
hendrikvincent 0:05ccbd4f84f1 905 namelen = LWIP_MIN(strlen(name), DNS_MAX_NAME_LENGTH-1);
hendrikvincent 0:05ccbd4f84f1 906 MEMCPY(pEntry->name, name, namelen);
hendrikvincent 0:05ccbd4f84f1 907 pEntry->name[namelen] = 0;
hendrikvincent 0:05ccbd4f84f1 908
hendrikvincent 0:05ccbd4f84f1 909 /* force to send query without waiting timer */
hendrikvincent 0:05ccbd4f84f1 910 dns_check_entry(i);
hendrikvincent 0:05ccbd4f84f1 911
hendrikvincent 0:05ccbd4f84f1 912 /* dns query is enqueued */
hendrikvincent 0:05ccbd4f84f1 913 return ERR_INPROGRESS;
hendrikvincent 0:05ccbd4f84f1 914 }
hendrikvincent 0:05ccbd4f84f1 915
hendrikvincent 0:05ccbd4f84f1 916 /**
hendrikvincent 0:05ccbd4f84f1 917 * Resolve a hostname (string) into an IP address.
hendrikvincent 0:05ccbd4f84f1 918 * NON-BLOCKING callback version for use with raw API!!!
hendrikvincent 0:05ccbd4f84f1 919 *
hendrikvincent 0:05ccbd4f84f1 920 * Returns immediately with one of err_t return codes:
hendrikvincent 0:05ccbd4f84f1 921 * - ERR_OK if hostname is a valid IP address string or the host
hendrikvincent 0:05ccbd4f84f1 922 * name is already in the local names table.
hendrikvincent 0:05ccbd4f84f1 923 * - ERR_INPROGRESS enqueue a request to be sent to the DNS server
hendrikvincent 0:05ccbd4f84f1 924 * for resolution if no errors are present.
hendrikvincent 0:05ccbd4f84f1 925 *
hendrikvincent 0:05ccbd4f84f1 926 * @param hostname the hostname that is to be queried
hendrikvincent 0:05ccbd4f84f1 927 * @param addr pointer to a ip_addr_t where to store the address if it is already
hendrikvincent 0:05ccbd4f84f1 928 * cached in the dns_table (only valid if ERR_OK is returned!)
hendrikvincent 0:05ccbd4f84f1 929 * @param found a callback function to be called on success, failure or timeout (only if
hendrikvincent 0:05ccbd4f84f1 930 * ERR_INPROGRESS is returned!)
hendrikvincent 0:05ccbd4f84f1 931 * @param callback_arg argument to pass to the callback function
hendrikvincent 0:05ccbd4f84f1 932 * @return a err_t return code.
hendrikvincent 0:05ccbd4f84f1 933 */
hendrikvincent 0:05ccbd4f84f1 934 err_t
hendrikvincent 0:05ccbd4f84f1 935 dns_gethostbyname(const char *hostname, ip_addr_t *addr, dns_found_callback found,
hendrikvincent 0:05ccbd4f84f1 936 void *callback_arg)
hendrikvincent 0:05ccbd4f84f1 937 {
hendrikvincent 0:05ccbd4f84f1 938 u32_t ipaddr;
hendrikvincent 0:05ccbd4f84f1 939 /* not initialized or no valid server yet, or invalid addr pointer
hendrikvincent 0:05ccbd4f84f1 940 * or invalid hostname or invalid hostname length */
hendrikvincent 0:05ccbd4f84f1 941 if ((dns_pcb == NULL) || (addr == NULL) ||
hendrikvincent 0:05ccbd4f84f1 942 (!hostname) || (!hostname[0]) ||
hendrikvincent 0:05ccbd4f84f1 943 (strlen(hostname) >= DNS_MAX_NAME_LENGTH)) {
hendrikvincent 0:05ccbd4f84f1 944 return ERR_VAL;
hendrikvincent 0:05ccbd4f84f1 945 }
hendrikvincent 0:05ccbd4f84f1 946
hendrikvincent 0:05ccbd4f84f1 947 #if LWIP_HAVE_LOOPIF
hendrikvincent 0:05ccbd4f84f1 948 if (strcmp(hostname, "localhost")==0) {
hendrikvincent 0:05ccbd4f84f1 949 ip_addr_set_loopback(addr);
hendrikvincent 0:05ccbd4f84f1 950 return ERR_OK;
hendrikvincent 0:05ccbd4f84f1 951 }
hendrikvincent 0:05ccbd4f84f1 952 #endif /* LWIP_HAVE_LOOPIF */
hendrikvincent 0:05ccbd4f84f1 953
hendrikvincent 0:05ccbd4f84f1 954 /* host name already in octet notation? set ip addr and return ERR_OK */
hendrikvincent 0:05ccbd4f84f1 955 ipaddr = ipaddr_addr(hostname);
hendrikvincent 0:05ccbd4f84f1 956 if (ipaddr == IPADDR_NONE) {
hendrikvincent 0:05ccbd4f84f1 957 /* already have this address cached? */
hendrikvincent 0:05ccbd4f84f1 958 ipaddr = dns_lookup(hostname);
hendrikvincent 0:05ccbd4f84f1 959 }
hendrikvincent 0:05ccbd4f84f1 960 if (ipaddr != IPADDR_NONE) {
hendrikvincent 0:05ccbd4f84f1 961 ip4_addr_set_u32(addr, ipaddr);
hendrikvincent 0:05ccbd4f84f1 962 return ERR_OK;
hendrikvincent 0:05ccbd4f84f1 963 }
hendrikvincent 0:05ccbd4f84f1 964
hendrikvincent 0:05ccbd4f84f1 965 /* queue query with specified callback */
hendrikvincent 0:05ccbd4f84f1 966 return dns_enqueue(hostname, found, callback_arg);
hendrikvincent 0:05ccbd4f84f1 967 }
hendrikvincent 0:05ccbd4f84f1 968
hendrikvincent 0:05ccbd4f84f1 969 #endif /* LWIP_DNS */