Donatien Garnier
NetServices Stack source
Dependents: HelloWorld ServoInterfaceBoardExample1 4180_Lab4
lwip/core/dns.c@0:632c9925f013, 2010-06-11 (annotated)
- Committer:
- donatien
- Date:
- Fri Jun 11 16:05:15 2010 +0000
- Revision:
- 0:632c9925f013
- Child:
- 2:a4f97773c90f
Who changed what in which revision?
| User | Revision | Line number | New contents of line |
|---|---|---|---|
| donatien | 0:632c9925f013 | 1 | /** |
| donatien | 0:632c9925f013 | 2 | * @file |
| donatien | 0:632c9925f013 | 3 | * DNS - host name to IP address resolver. |
| donatien | 0:632c9925f013 | 4 | * |
| donatien | 0:632c9925f013 | 5 | */ |
| donatien | 0:632c9925f013 | 6 | |
| donatien | 0:632c9925f013 | 7 | /** |
| donatien | 0:632c9925f013 | 8 | |
| donatien | 0:632c9925f013 | 9 | * This file implements a DNS host name to IP address resolver. |
| donatien | 0:632c9925f013 | 10 | |
| donatien | 0:632c9925f013 | 11 | * Port to lwIP from uIP |
| donatien | 0:632c9925f013 | 12 | * by Jim Pettinato April 2007 |
| donatien | 0:632c9925f013 | 13 | |
| donatien | 0:632c9925f013 | 14 | * uIP version Copyright (c) 2002-2003, Adam Dunkels. |
| donatien | 0:632c9925f013 | 15 | * All rights reserved. |
| donatien | 0:632c9925f013 | 16 | * |
| donatien | 0:632c9925f013 | 17 | * Redistribution and use in source and binary forms, with or without |
| donatien | 0:632c9925f013 | 18 | * modification, are permitted provided that the following conditions |
| donatien | 0:632c9925f013 | 19 | * are met: |
| donatien | 0:632c9925f013 | 20 | * 1. Redistributions of source code must retain the above copyright |
| donatien | 0:632c9925f013 | 21 | * notice, this list of conditions and the following disclaimer. |
| donatien | 0:632c9925f013 | 22 | * 2. Redistributions in binary form must reproduce the above copyright |
| donatien | 0:632c9925f013 | 23 | * notice, this list of conditions and the following disclaimer in the |
| donatien | 0:632c9925f013 | 24 | * documentation and/or other materials provided with the distribution. |
| donatien | 0:632c9925f013 | 25 | * 3. The name of the author may not be used to endorse or promote |
| donatien | 0:632c9925f013 | 26 | * products derived from this software without specific prior |
| donatien | 0:632c9925f013 | 27 | * written permission. |
| donatien | 0:632c9925f013 | 28 | * |
| donatien | 0:632c9925f013 | 29 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS |
| donatien | 0:632c9925f013 | 30 | * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED |
| donatien | 0:632c9925f013 | 31 | * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
| donatien | 0:632c9925f013 | 32 | * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY |
| donatien | 0:632c9925f013 | 33 | * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
| donatien | 0:632c9925f013 | 34 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE |
| donatien | 0:632c9925f013 | 35 | * GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS |
| donatien | 0:632c9925f013 | 36 | * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, |
| donatien | 0:632c9925f013 | 37 | * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING |
| donatien | 0:632c9925f013 | 38 | * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS |
| donatien | 0:632c9925f013 | 39 | * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| donatien | 0:632c9925f013 | 40 | * |
| donatien | 0:632c9925f013 | 41 | * |
| donatien | 0:632c9925f013 | 42 | * DNS.C |
| donatien | 0:632c9925f013 | 43 | * |
| donatien | 0:632c9925f013 | 44 | * The lwIP DNS resolver functions are used to lookup a host name and |
| donatien | 0:632c9925f013 | 45 | * map it to a numerical IP address. It maintains a list of resolved |
| donatien | 0:632c9925f013 | 46 | * hostnames that can be queried with the dns_lookup() function. |
| donatien | 0:632c9925f013 | 47 | * New hostnames can be resolved using the dns_query() function. |
| donatien | 0:632c9925f013 | 48 | * |
| donatien | 0:632c9925f013 | 49 | * The lwIP version of the resolver also adds a non-blocking version of |
| donatien | 0:632c9925f013 | 50 | * gethostbyname() that will work with a raw API application. This function |
| donatien | 0:632c9925f013 | 51 | * checks for an IP address string first and converts it if it is valid. |
| donatien | 0:632c9925f013 | 52 | * gethostbyname() then does a dns_lookup() to see if the name is |
| donatien | 0:632c9925f013 | 53 | * already in the table. If so, the IP is returned. If not, a query is |
| donatien | 0:632c9925f013 | 54 | * issued and the function returns with a ERR_INPROGRESS status. The app |
| donatien | 0:632c9925f013 | 55 | * using the dns client must then go into a waiting state. |
| donatien | 0:632c9925f013 | 56 | * |
| donatien | 0:632c9925f013 | 57 | * Once a hostname has been resolved (or found to be non-existent), |
| donatien | 0:632c9925f013 | 58 | * the resolver code calls a specified callback function (which |
| donatien | 0:632c9925f013 | 59 | * must be implemented by the module that uses the resolver). |
| donatien | 0:632c9925f013 | 60 | */ |
| donatien | 0:632c9925f013 | 61 | |
| donatien | 0:632c9925f013 | 62 | /*----------------------------------------------------------------------------- |
| donatien | 0:632c9925f013 | 63 | * RFC 1035 - Domain names - implementation and specification |
| donatien | 0:632c9925f013 | 64 | * RFC 2181 - Clarifications to the DNS Specification |
| donatien | 0:632c9925f013 | 65 | *----------------------------------------------------------------------------*/ |
| donatien | 0:632c9925f013 | 66 | |
| donatien | 0:632c9925f013 | 67 | /** @todo: define good default values (rfc compliance) */ |
| donatien | 0:632c9925f013 | 68 | /** @todo: improve answer parsing, more checkings... */ |
| donatien | 0:632c9925f013 | 69 | /** @todo: check RFC1035 - 7.3. Processing responses */ |
| donatien | 0:632c9925f013 | 70 | |
| donatien | 0:632c9925f013 | 71 | /*----------------------------------------------------------------------------- |
| donatien | 0:632c9925f013 | 72 | * Includes |
| donatien | 0:632c9925f013 | 73 | *----------------------------------------------------------------------------*/ |
| donatien | 0:632c9925f013 | 74 | |
| donatien | 0:632c9925f013 | 75 | #include "lwip/opt.h" |
| donatien | 0:632c9925f013 | 76 | |
| donatien | 0:632c9925f013 | 77 | #if LWIP_DNS /* don't build if not configured for use in lwipopts.h */ |
| donatien | 0:632c9925f013 | 78 | |
| donatien | 0:632c9925f013 | 79 | #include "lwip/udp.h" |
| donatien | 0:632c9925f013 | 80 | #include "lwip/mem.h" |
| donatien | 0:632c9925f013 | 81 | #include "lwip/dns.h" |
| donatien | 0:632c9925f013 | 82 | |
| donatien | 0:632c9925f013 | 83 | #include <string.h> |
| donatien | 0:632c9925f013 | 84 | |
| donatien | 0:632c9925f013 | 85 | /** DNS server IP address */ |
| donatien | 0:632c9925f013 | 86 | #ifndef DNS_SERVER_ADDRESS |
| donatien | 0:632c9925f013 | 87 | #define DNS_SERVER_ADDRESS(ipaddr) (ip4_addr_set_u32(ipaddr, ipaddr_addr("208.67.222.222"))) /* resolver1.opendns.com */ |
| donatien | 0:632c9925f013 | 88 | #endif |
| donatien | 0:632c9925f013 | 89 | |
| donatien | 0:632c9925f013 | 90 | /** DNS server port address */ |
| donatien | 0:632c9925f013 | 91 | #ifndef DNS_SERVER_PORT |
| donatien | 0:632c9925f013 | 92 | #define DNS_SERVER_PORT 53 |
| donatien | 0:632c9925f013 | 93 | #endif |
| donatien | 0:632c9925f013 | 94 | |
| donatien | 0:632c9925f013 | 95 | /** DNS maximum number of retries when asking for a name, before "timeout". */ |
| donatien | 0:632c9925f013 | 96 | #ifndef DNS_MAX_RETRIES |
| donatien | 0:632c9925f013 | 97 | #define DNS_MAX_RETRIES 4 |
| donatien | 0:632c9925f013 | 98 | #endif |
| donatien | 0:632c9925f013 | 99 | |
| donatien | 0:632c9925f013 | 100 | /** DNS resource record max. TTL (one week as default) */ |
| donatien | 0:632c9925f013 | 101 | #ifndef DNS_MAX_TTL |
| donatien | 0:632c9925f013 | 102 | #define DNS_MAX_TTL 604800 |
| donatien | 0:632c9925f013 | 103 | #endif |
| donatien | 0:632c9925f013 | 104 | |
| donatien | 0:632c9925f013 | 105 | /* DNS protocol flags */ |
| donatien | 0:632c9925f013 | 106 | #define DNS_FLAG1_RESPONSE 0x80 |
| donatien | 0:632c9925f013 | 107 | #define DNS_FLAG1_OPCODE_STATUS 0x10 |
| donatien | 0:632c9925f013 | 108 | #define DNS_FLAG1_OPCODE_INVERSE 0x08 |
| donatien | 0:632c9925f013 | 109 | #define DNS_FLAG1_OPCODE_STANDARD 0x00 |
| donatien | 0:632c9925f013 | 110 | #define DNS_FLAG1_AUTHORATIVE 0x04 |
| donatien | 0:632c9925f013 | 111 | #define DNS_FLAG1_TRUNC 0x02 |
| donatien | 0:632c9925f013 | 112 | #define DNS_FLAG1_RD 0x01 |
| donatien | 0:632c9925f013 | 113 | #define DNS_FLAG2_RA 0x80 |
| donatien | 0:632c9925f013 | 114 | #define DNS_FLAG2_ERR_MASK 0x0f |
| donatien | 0:632c9925f013 | 115 | #define DNS_FLAG2_ERR_NONE 0x00 |
| donatien | 0:632c9925f013 | 116 | #define DNS_FLAG2_ERR_NAME 0x03 |
| donatien | 0:632c9925f013 | 117 | |
| donatien | 0:632c9925f013 | 118 | /* DNS protocol states */ |
| donatien | 0:632c9925f013 | 119 | #define DNS_STATE_UNUSED 0 |
| donatien | 0:632c9925f013 | 120 | #define DNS_STATE_NEW 1 |
| donatien | 0:632c9925f013 | 121 | #define DNS_STATE_ASKING 2 |
| donatien | 0:632c9925f013 | 122 | #define DNS_STATE_DONE 3 |
| donatien | 0:632c9925f013 | 123 | |
| donatien | 0:632c9925f013 | 124 | #ifdef PACK_STRUCT_USE_INCLUDES |
| donatien | 0:632c9925f013 | 125 | # include "arch/bpstruct.h" |
| donatien | 0:632c9925f013 | 126 | #endif |
| donatien | 0:632c9925f013 | 127 | PACK_STRUCT_BEGIN |
| donatien | 0:632c9925f013 | 128 | /** DNS message header */ |
| donatien | 0:632c9925f013 | 129 | struct dns_hdr { |
| donatien | 0:632c9925f013 | 130 | PACK_STRUCT_FIELD(u16_t id); |
| donatien | 0:632c9925f013 | 131 | PACK_STRUCT_FIELD(u8_t flags1); |
| donatien | 0:632c9925f013 | 132 | PACK_STRUCT_FIELD(u8_t flags2); |
| donatien | 0:632c9925f013 | 133 | PACK_STRUCT_FIELD(u16_t numquestions); |
| donatien | 0:632c9925f013 | 134 | PACK_STRUCT_FIELD(u16_t numanswers); |
| donatien | 0:632c9925f013 | 135 | PACK_STRUCT_FIELD(u16_t numauthrr); |
| donatien | 0:632c9925f013 | 136 | PACK_STRUCT_FIELD(u16_t numextrarr); |
| donatien | 0:632c9925f013 | 137 | } PACK_STRUCT_STRUCT; |
| donatien | 0:632c9925f013 | 138 | PACK_STRUCT_END |
| donatien | 0:632c9925f013 | 139 | #ifdef PACK_STRUCT_USE_INCLUDES |
| donatien | 0:632c9925f013 | 140 | # include "arch/epstruct.h" |
| donatien | 0:632c9925f013 | 141 | #endif |
| donatien | 0:632c9925f013 | 142 | #define SIZEOF_DNS_HDR 12 |
| donatien | 0:632c9925f013 | 143 | |
| donatien | 0:632c9925f013 | 144 | /** DNS query message structure. |
| donatien | 0:632c9925f013 | 145 | No packing needed: only used locally on the stack. */ |
| donatien | 0:632c9925f013 | 146 | PACK_STRUCT_BEGIN |
| donatien | 0:632c9925f013 | 147 | struct dns_query { |
| donatien | 0:632c9925f013 | 148 | /* DNS query record starts with either a domain name or a pointer |
| donatien | 0:632c9925f013 | 149 | to a name already present somewhere in the packet. */ |
| donatien | 0:632c9925f013 | 150 | u16_t type; |
| donatien | 0:632c9925f013 | 151 | u16_t cls; |
| donatien | 0:632c9925f013 | 152 | } PACK_STRUCT_STRUCT; |
| donatien | 0:632c9925f013 | 153 | PACK_STRUCT_END |
| donatien | 0:632c9925f013 | 154 | #define SIZEOF_DNS_QUERY 4 |
| donatien | 0:632c9925f013 | 155 | |
| donatien | 0:632c9925f013 | 156 | /** DNS answer message structure. |
| donatien | 0:632c9925f013 | 157 | No packing needed: only used locally on the stack. */ |
| donatien | 0:632c9925f013 | 158 | PACK_STRUCT_BEGIN |
| donatien | 0:632c9925f013 | 159 | struct dns_answer { |
| donatien | 0:632c9925f013 | 160 | /* DNS answer record starts with either a domain name or a pointer |
| donatien | 0:632c9925f013 | 161 | to a name already present somewhere in the packet. */ |
| donatien | 0:632c9925f013 | 162 | u16_t type; |
| donatien | 0:632c9925f013 | 163 | u16_t cls; |
| donatien | 0:632c9925f013 | 164 | u32_t ttl; |
| donatien | 0:632c9925f013 | 165 | u16_t len; |
| donatien | 0:632c9925f013 | 166 | } PACK_STRUCT_STRUCT; |
| donatien | 0:632c9925f013 | 167 | PACK_STRUCT_END |
| donatien | 0:632c9925f013 | 168 | #define SIZEOF_DNS_ANSWER 10 |
| donatien | 0:632c9925f013 | 169 | |
| donatien | 0:632c9925f013 | 170 | /** DNS table entry */ |
| donatien | 0:632c9925f013 | 171 | struct dns_table_entry { |
| donatien | 0:632c9925f013 | 172 | u8_t state; |
| donatien | 0:632c9925f013 | 173 | u8_t numdns; |
| donatien | 0:632c9925f013 | 174 | u8_t tmr; |
| donatien | 0:632c9925f013 | 175 | u8_t retries; |
| donatien | 0:632c9925f013 | 176 | u8_t seqno; |
| donatien | 0:632c9925f013 | 177 | u8_t err; |
| donatien | 0:632c9925f013 | 178 | u32_t ttl; |
| donatien | 0:632c9925f013 | 179 | char name[DNS_MAX_NAME_LENGTH]; |
| donatien | 0:632c9925f013 | 180 | ip_addr_t ipaddr; |
| donatien | 0:632c9925f013 | 181 | /* pointer to callback on DNS query done */ |
| donatien | 0:632c9925f013 | 182 | dns_found_callback found; |
| donatien | 0:632c9925f013 | 183 | void *arg; |
| donatien | 0:632c9925f013 | 184 | }; |
| donatien | 0:632c9925f013 | 185 | |
| donatien | 0:632c9925f013 | 186 | #if DNS_LOCAL_HOSTLIST |
| donatien | 0:632c9925f013 | 187 | /** struct used for local host-list */ |
| donatien | 0:632c9925f013 | 188 | struct local_hostlist_entry { |
| donatien | 0:632c9925f013 | 189 | /** static hostname */ |
| donatien | 0:632c9925f013 | 190 | const char *name; |
| donatien | 0:632c9925f013 | 191 | /** static host address in network byteorder */ |
| donatien | 0:632c9925f013 | 192 | ip_addr_t addr; |
| donatien | 0:632c9925f013 | 193 | struct local_hostlist_entry *next; |
| donatien | 0:632c9925f013 | 194 | }; |
| donatien | 0:632c9925f013 | 195 | |
| donatien | 0:632c9925f013 | 196 | #if DNS_LOCAL_HOSTLIST_IS_DYNAMIC |
| donatien | 0:632c9925f013 | 197 | /** Local host-list. For hostnames in this list, no |
| donatien | 0:632c9925f013 | 198 | * external name resolution is performed */ |
| donatien | 0:632c9925f013 | 199 | static struct local_hostlist_entry *local_hostlist_dynamic; |
| donatien | 0:632c9925f013 | 200 | #else /* DNS_LOCAL_HOSTLIST_IS_DYNAMIC */ |
| donatien | 0:632c9925f013 | 201 | |
| donatien | 0:632c9925f013 | 202 | /** Defining this allows the local_hostlist_static to be placed in a different |
| donatien | 0:632c9925f013 | 203 | * linker section (e.g. FLASH) */ |
| donatien | 0:632c9925f013 | 204 | #ifndef DNS_LOCAL_HOSTLIST_STORAGE_PRE |
| donatien | 0:632c9925f013 | 205 | #define DNS_LOCAL_HOSTLIST_STORAGE_PRE static |
| donatien | 0:632c9925f013 | 206 | #endif /* DNS_LOCAL_HOSTLIST_STORAGE_PRE */ |
| donatien | 0:632c9925f013 | 207 | /** Defining this allows the local_hostlist_static to be placed in a different |
| donatien | 0:632c9925f013 | 208 | * linker section (e.g. FLASH) */ |
| donatien | 0:632c9925f013 | 209 | #ifndef DNS_LOCAL_HOSTLIST_STORAGE_POST |
| donatien | 0:632c9925f013 | 210 | #define DNS_LOCAL_HOSTLIST_STORAGE_POST |
| donatien | 0:632c9925f013 | 211 | #endif /* DNS_LOCAL_HOSTLIST_STORAGE_POST */ |
| donatien | 0:632c9925f013 | 212 | DNS_LOCAL_HOSTLIST_STORAGE_PRE struct local_hostlist_entry local_hostlist_static[] |
| donatien | 0:632c9925f013 | 213 | DNS_LOCAL_HOSTLIST_STORAGE_POST = DNS_LOCAL_HOSTLIST_INIT; |
| donatien | 0:632c9925f013 | 214 | |
| donatien | 0:632c9925f013 | 215 | #endif /* DNS_LOCAL_HOSTLIST_IS_DYNAMIC */ |
| donatien | 0:632c9925f013 | 216 | |
| donatien | 0:632c9925f013 | 217 | static void dns_init_local(); |
| donatien | 0:632c9925f013 | 218 | #endif /* DNS_LOCAL_HOSTLIST */ |
| donatien | 0:632c9925f013 | 219 | |
| donatien | 0:632c9925f013 | 220 | |
| donatien | 0:632c9925f013 | 221 | /* forward declarations */ |
| donatien | 0:632c9925f013 | 222 | static void dns_recv(void *s, struct udp_pcb *pcb, struct pbuf *p, ip_addr_t *addr, u16_t port); |
| donatien | 0:632c9925f013 | 223 | static void dns_check_entries(void); |
| donatien | 0:632c9925f013 | 224 | |
| donatien | 0:632c9925f013 | 225 | /*----------------------------------------------------------------------------- |
| donatien | 0:632c9925f013 | 226 | * Globales |
| donatien | 0:632c9925f013 | 227 | *----------------------------------------------------------------------------*/ |
| donatien | 0:632c9925f013 | 228 | |
| donatien | 0:632c9925f013 | 229 | /* DNS variables */ |
| donatien | 0:632c9925f013 | 230 | static struct udp_pcb *dns_pcb; |
| donatien | 0:632c9925f013 | 231 | static u8_t dns_seqno; |
| donatien | 0:632c9925f013 | 232 | static struct dns_table_entry dns_table[DNS_TABLE_SIZE]; |
| donatien | 0:632c9925f013 | 233 | static ip_addr_t dns_servers[DNS_MAX_SERVERS]; |
| donatien | 0:632c9925f013 | 234 | /** Contiguous buffer for processing responses */ |
| donatien | 0:632c9925f013 | 235 | static u8_t dns_payload_buffer[LWIP_MEM_ALIGN_BUFFER(DNS_MSG_SIZE)]; |
| donatien | 0:632c9925f013 | 236 | static u8_t* dns_payload; |
| donatien | 0:632c9925f013 | 237 | |
| donatien | 0:632c9925f013 | 238 | /** |
| donatien | 0:632c9925f013 | 239 | * Initialize the resolver: set up the UDP pcb and configure the default server |
| donatien | 0:632c9925f013 | 240 | * (DNS_SERVER_ADDRESS). |
| donatien | 0:632c9925f013 | 241 | */ |
| donatien | 0:632c9925f013 | 242 | void |
| donatien | 0:632c9925f013 | 243 | dns_init() |
| donatien | 0:632c9925f013 | 244 | { |
| donatien | 0:632c9925f013 | 245 | ip_addr_t dnsserver; |
| donatien | 0:632c9925f013 | 246 | |
| donatien | 0:632c9925f013 | 247 | dns_payload = (u8_t *)LWIP_MEM_ALIGN(dns_payload_buffer); |
| donatien | 0:632c9925f013 | 248 | |
| donatien | 0:632c9925f013 | 249 | /* initialize default DNS server address */ |
| donatien | 0:632c9925f013 | 250 | DNS_SERVER_ADDRESS(&dnsserver); |
| donatien | 0:632c9925f013 | 251 | |
| donatien | 0:632c9925f013 | 252 | LWIP_DEBUGF(DNS_DEBUG, ("dns_init: initializing\n")); |
| donatien | 0:632c9925f013 | 253 | |
| donatien | 0:632c9925f013 | 254 | /* if dns client not yet initialized... */ |
| donatien | 0:632c9925f013 | 255 | if (dns_pcb == NULL) { |
| donatien | 0:632c9925f013 | 256 | dns_pcb = udp_new(); |
| donatien | 0:632c9925f013 | 257 | |
| donatien | 0:632c9925f013 | 258 | if (dns_pcb != NULL) { |
| donatien | 0:632c9925f013 | 259 | /* initialize DNS table not needed (initialized to zero since it is a |
| donatien | 0:632c9925f013 | 260 | * global variable) */ |
| donatien | 0:632c9925f013 | 261 | LWIP_ASSERT("For implicit initialization to work, DNS_STATE_UNUSED needs to be 0", |
| donatien | 0:632c9925f013 | 262 | DNS_STATE_UNUSED == 0); |
| donatien | 0:632c9925f013 | 263 | |
| donatien | 0:632c9925f013 | 264 | /* initialize DNS client */ |
| donatien | 0:632c9925f013 | 265 | udp_bind(dns_pcb, IP_ADDR_ANY, 0); |
| donatien | 0:632c9925f013 | 266 | udp_recv(dns_pcb, dns_recv, NULL); |
| donatien | 0:632c9925f013 | 267 | |
| donatien | 0:632c9925f013 | 268 | /* initialize default DNS primary server */ |
| donatien | 0:632c9925f013 | 269 | dns_setserver(0, &dnsserver); |
| donatien | 0:632c9925f013 | 270 | } |
| donatien | 0:632c9925f013 | 271 | } |
| donatien | 0:632c9925f013 | 272 | #if DNS_LOCAL_HOSTLIST |
| donatien | 0:632c9925f013 | 273 | dns_init_local(); |
| donatien | 0:632c9925f013 | 274 | #endif |
| donatien | 0:632c9925f013 | 275 | } |
| donatien | 0:632c9925f013 | 276 | |
| donatien | 0:632c9925f013 | 277 | /** |
| donatien | 0:632c9925f013 | 278 | * Initialize one of the DNS servers. |
| donatien | 0:632c9925f013 | 279 | * |
| donatien | 0:632c9925f013 | 280 | * @param numdns the index of the DNS server to set must be < DNS_MAX_SERVERS |
| donatien | 0:632c9925f013 | 281 | * @param dnsserver IP address of the DNS server to set |
| donatien | 0:632c9925f013 | 282 | */ |
| donatien | 0:632c9925f013 | 283 | void |
| donatien | 0:632c9925f013 | 284 | dns_setserver(u8_t numdns, ip_addr_t *dnsserver) |
| donatien | 0:632c9925f013 | 285 | { |
| donatien | 0:632c9925f013 | 286 | if ((numdns < DNS_MAX_SERVERS) && (dns_pcb != NULL) && |
| donatien | 0:632c9925f013 | 287 | (dnsserver != NULL) && !ip_addr_isany(dnsserver)) { |
| donatien | 0:632c9925f013 | 288 | dns_servers[numdns] = (*dnsserver); |
| donatien | 0:632c9925f013 | 289 | } |
| donatien | 0:632c9925f013 | 290 | } |
| donatien | 0:632c9925f013 | 291 | |
| donatien | 0:632c9925f013 | 292 | /** |
| donatien | 0:632c9925f013 | 293 | * Obtain one of the currently configured DNS server. |
| donatien | 0:632c9925f013 | 294 | * |
| donatien | 0:632c9925f013 | 295 | * @param numdns the index of the DNS server |
| donatien | 0:632c9925f013 | 296 | * @return IP address of the indexed DNS server or "ip_addr_any" if the DNS |
| donatien | 0:632c9925f013 | 297 | * server has not been configured. |
| donatien | 0:632c9925f013 | 298 | */ |
| donatien | 0:632c9925f013 | 299 | ip_addr_t |
| donatien | 0:632c9925f013 | 300 | dns_getserver(u8_t numdns) |
| donatien | 0:632c9925f013 | 301 | { |
| donatien | 0:632c9925f013 | 302 | if (numdns < DNS_MAX_SERVERS) { |
| donatien | 0:632c9925f013 | 303 | return dns_servers[numdns]; |
| donatien | 0:632c9925f013 | 304 | } else { |
| donatien | 0:632c9925f013 | 305 | return *IP_ADDR_ANY; |
| donatien | 0:632c9925f013 | 306 | } |
| donatien | 0:632c9925f013 | 307 | } |
| donatien | 0:632c9925f013 | 308 | |
| donatien | 0:632c9925f013 | 309 | /** |
| donatien | 0:632c9925f013 | 310 | * The DNS resolver client timer - handle retries and timeouts and should |
| donatien | 0:632c9925f013 | 311 | * be called every DNS_TMR_INTERVAL milliseconds (every second by default). |
| donatien | 0:632c9925f013 | 312 | */ |
| donatien | 0:632c9925f013 | 313 | void |
| donatien | 0:632c9925f013 | 314 | dns_tmr(void) |
| donatien | 0:632c9925f013 | 315 | { |
| donatien | 0:632c9925f013 | 316 | if (dns_pcb != NULL) { |
| donatien | 0:632c9925f013 | 317 | LWIP_DEBUGF(DNS_DEBUG, ("dns_tmr: dns_check_entries\n")); |
| donatien | 0:632c9925f013 | 318 | dns_check_entries(); |
| donatien | 0:632c9925f013 | 319 | } |
| donatien | 0:632c9925f013 | 320 | } |
| donatien | 0:632c9925f013 | 321 | |
| donatien | 0:632c9925f013 | 322 | #if DNS_LOCAL_HOSTLIST |
| donatien | 0:632c9925f013 | 323 | static void |
| donatien | 0:632c9925f013 | 324 | dns_init_local() |
| donatien | 0:632c9925f013 | 325 | { |
| donatien | 0:632c9925f013 | 326 | #if DNS_LOCAL_HOSTLIST_IS_DYNAMIC && defined(DNS_LOCAL_HOSTLIST_INIT) |
| donatien | 0:632c9925f013 | 327 | int i; |
| donatien | 0:632c9925f013 | 328 | struct local_hostlist_entry *entry; |
| donatien | 0:632c9925f013 | 329 | /* Dynamic: copy entries from DNS_LOCAL_HOSTLIST_INIT to list */ |
| donatien | 0:632c9925f013 | 330 | struct local_hostlist_entry local_hostlist_init[] = DNS_LOCAL_HOSTLIST_INIT; |
| donatien | 0:632c9925f013 | 331 | size_t namelen; |
| donatien | 0:632c9925f013 | 332 | for (i = 0; i < sizeof(local_hostlist_init) / sizeof(struct local_hostlist_entry); i++) { |
| donatien | 0:632c9925f013 | 333 | struct local_hostlist_entry *init_entry = &local_hostlist_init[i]; |
| donatien | 0:632c9925f013 | 334 | LWIP_ASSERT("invalid host name (NULL)", init_entry->name != NULL); |
| donatien | 0:632c9925f013 | 335 | namelen = strlen(init_entry->name); |
| donatien | 0:632c9925f013 | 336 | entry = mem_malloc((mem_size_t)(sizeof(struct local_hostlist_entry) + namelen + 1)); |
| donatien | 0:632c9925f013 | 337 | LWIP_ASSERT("mem-error in dns_init_local", entry != NULL); |
| donatien | 0:632c9925f013 | 338 | if (entry != NULL) { |
| donatien | 0:632c9925f013 | 339 | entry->name = (char*)entry + sizeof(struct local_hostlist_entry); |
| donatien | 0:632c9925f013 | 340 | MEMCPY((char*)entry->name, init_entry->name, namelen); |
| donatien | 0:632c9925f013 | 341 | ((char*)entry->name)[namelen] = 0; |
| donatien | 0:632c9925f013 | 342 | entry->addr = init_entry->addr; |
| donatien | 0:632c9925f013 | 343 | entry->next = local_hostlist_dynamic; |
| donatien | 0:632c9925f013 | 344 | local_hostlist_dynamic = entry; |
| donatien | 0:632c9925f013 | 345 | } |
| donatien | 0:632c9925f013 | 346 | } |
| donatien | 0:632c9925f013 | 347 | #endif /* DNS_LOCAL_HOSTLIST_IS_DYNAMIC && defined(DNS_LOCAL_HOSTLIST_INIT) */ |
| donatien | 0:632c9925f013 | 348 | } |
| donatien | 0:632c9925f013 | 349 | |
| donatien | 0:632c9925f013 | 350 | /** |
| donatien | 0:632c9925f013 | 351 | * Scans the local host-list for a hostname. |
| donatien | 0:632c9925f013 | 352 | * |
| donatien | 0:632c9925f013 | 353 | * @param hostname Hostname to look for in the local host-list |
| donatien | 0:632c9925f013 | 354 | * @return The first IP address for the hostname in the local host-list or |
| donatien | 0:632c9925f013 | 355 | * IPADDR_NONE if not found. |
| donatien | 0:632c9925f013 | 356 | */ |
| donatien | 0:632c9925f013 | 357 | static u32_t |
| donatien | 0:632c9925f013 | 358 | dns_lookup_local(const char *hostname) |
| donatien | 0:632c9925f013 | 359 | { |
| donatien | 0:632c9925f013 | 360 | #if DNS_LOCAL_HOSTLIST_IS_DYNAMIC |
| donatien | 0:632c9925f013 | 361 | struct local_hostlist_entry *entry = local_hostlist_dynamic; |
| donatien | 0:632c9925f013 | 362 | while(entry != NULL) { |
| donatien | 0:632c9925f013 | 363 | if(strcmp(entry->name, hostname) == 0) { |
| donatien | 0:632c9925f013 | 364 | return ip4_addr_get_u32(&entry->addr); |
| donatien | 0:632c9925f013 | 365 | } |
| donatien | 0:632c9925f013 | 366 | entry = entry->next; |
| donatien | 0:632c9925f013 | 367 | } |
| donatien | 0:632c9925f013 | 368 | #else /* DNS_LOCAL_HOSTLIST_IS_DYNAMIC */ |
| donatien | 0:632c9925f013 | 369 | int i; |
| donatien | 0:632c9925f013 | 370 | for (i = 0; i < sizeof(local_hostlist_static) / sizeof(struct local_hostlist_entry); i++) { |
| donatien | 0:632c9925f013 | 371 | if(strcmp(local_hostlist_static[i].name, hostname) == 0) { |
| donatien | 0:632c9925f013 | 372 | return ip4_addr_get_u32(&local_hostlist_static[i].addr); |
| donatien | 0:632c9925f013 | 373 | } |
| donatien | 0:632c9925f013 | 374 | } |
| donatien | 0:632c9925f013 | 375 | #endif /* DNS_LOCAL_HOSTLIST_IS_DYNAMIC */ |
| donatien | 0:632c9925f013 | 376 | return IPADDR_NONE; |
| donatien | 0:632c9925f013 | 377 | } |
| donatien | 0:632c9925f013 | 378 | |
| donatien | 0:632c9925f013 | 379 | #if DNS_LOCAL_HOSTLIST_IS_DYNAMIC |
| donatien | 0:632c9925f013 | 380 | /** Remove all entries from the local host-list for a specific hostname |
| donatien | 0:632c9925f013 | 381 | * and/or IP addess |
| donatien | 0:632c9925f013 | 382 | * |
| donatien | 0:632c9925f013 | 383 | * @param hostname hostname for which entries shall be removed from the local |
| donatien | 0:632c9925f013 | 384 | * host-list |
| donatien | 0:632c9925f013 | 385 | * @param addr address for which entries shall be removed from the local host-list |
| donatien | 0:632c9925f013 | 386 | * @return the number of removed entries |
| donatien | 0:632c9925f013 | 387 | */ |
| donatien | 0:632c9925f013 | 388 | int |
| donatien | 0:632c9925f013 | 389 | dns_local_removehost(const char *hostname, const ip_addr_t *addr) |
| donatien | 0:632c9925f013 | 390 | { |
| donatien | 0:632c9925f013 | 391 | int removed = 0; |
| donatien | 0:632c9925f013 | 392 | struct local_hostlist_entry *entry = local_hostlist_dynamic; |
| donatien | 0:632c9925f013 | 393 | struct local_hostlist_entry *last_entry = NULL; |
| donatien | 0:632c9925f013 | 394 | while (entry != NULL) { |
| donatien | 0:632c9925f013 | 395 | if (((hostname == NULL) || !strcmp(entry->name, hostname)) && |
| donatien | 0:632c9925f013 | 396 | ((addr == NULL) || ip_addr_cmp(&entry->addr, addr))) { |
| donatien | 0:632c9925f013 | 397 | struct local_hostlist_entry *free_entry; |
| donatien | 0:632c9925f013 | 398 | if (last_entry != NULL) { |
| donatien | 0:632c9925f013 | 399 | last_entry->next = entry->next; |
| donatien | 0:632c9925f013 | 400 | } else { |
| donatien | 0:632c9925f013 | 401 | local_hostlist_dynamic = entry->next; |
| donatien | 0:632c9925f013 | 402 | } |
| donatien | 0:632c9925f013 | 403 | free_entry = entry; |
| donatien | 0:632c9925f013 | 404 | entry = entry->next; |
| donatien | 0:632c9925f013 | 405 | mem_free(free_entry); |
| donatien | 0:632c9925f013 | 406 | removed++; |
| donatien | 0:632c9925f013 | 407 | } else { |
| donatien | 0:632c9925f013 | 408 | last_entry = entry; |
| donatien | 0:632c9925f013 | 409 | entry = entry->next; |
| donatien | 0:632c9925f013 | 410 | } |
| donatien | 0:632c9925f013 | 411 | } |
| donatien | 0:632c9925f013 | 412 | return removed; |
| donatien | 0:632c9925f013 | 413 | } |
| donatien | 0:632c9925f013 | 414 | |
| donatien | 0:632c9925f013 | 415 | /** |
| donatien | 0:632c9925f013 | 416 | * Add a hostname/IP address pair to the local host-list. |
| donatien | 0:632c9925f013 | 417 | * Duplicates are not checked. |
| donatien | 0:632c9925f013 | 418 | * |
| donatien | 0:632c9925f013 | 419 | * @param hostname hostname of the new entry |
| donatien | 0:632c9925f013 | 420 | * @param addr IP address of the new entry |
| donatien | 0:632c9925f013 | 421 | * @return ERR_OK if succeeded or ERR_MEM on memory error |
| donatien | 0:632c9925f013 | 422 | */ |
| donatien | 0:632c9925f013 | 423 | err_t |
| donatien | 0:632c9925f013 | 424 | dns_local_addhost(const char *hostname, const ip_addr_t *addr) |
| donatien | 0:632c9925f013 | 425 | { |
| donatien | 0:632c9925f013 | 426 | struct local_hostlist_entry *entry; |
| donatien | 0:632c9925f013 | 427 | size_t namelen; |
| donatien | 0:632c9925f013 | 428 | LWIP_ASSERT("invalid host name (NULL)", hostname != NULL); |
| donatien | 0:632c9925f013 | 429 | namelen = strlen(hostname); |
| donatien | 0:632c9925f013 | 430 | entry = mem_malloc((mem_size_t)(sizeof(struct local_hostlist_entry) + namelen + 1)); |
| donatien | 0:632c9925f013 | 431 | if (entry == NULL) { |
| donatien | 0:632c9925f013 | 432 | return ERR_MEM; |
| donatien | 0:632c9925f013 | 433 | } |
| donatien | 0:632c9925f013 | 434 | entry->name = (char*)entry + sizeof(struct local_hostlist_entry); |
| donatien | 0:632c9925f013 | 435 | MEMCPY((char*)entry->name, hostname, namelen); |
| donatien | 0:632c9925f013 | 436 | ((char*)entry->name)[namelen] = 0; |
| donatien | 0:632c9925f013 | 437 | ip_addr_copy(entry->addr, *addr); |
| donatien | 0:632c9925f013 | 438 | entry->next = local_hostlist_dynamic; |
| donatien | 0:632c9925f013 | 439 | local_hostlist_dynamic = entry; |
| donatien | 0:632c9925f013 | 440 | return ERR_OK; |
| donatien | 0:632c9925f013 | 441 | } |
| donatien | 0:632c9925f013 | 442 | #endif /* DNS_LOCAL_HOSTLIST_IS_DYNAMIC*/ |
| donatien | 0:632c9925f013 | 443 | #endif /* DNS_LOCAL_HOSTLIST */ |
| donatien | 0:632c9925f013 | 444 | |
| donatien | 0:632c9925f013 | 445 | /** |
| donatien | 0:632c9925f013 | 446 | * Look up a hostname in the array of known hostnames. |
| donatien | 0:632c9925f013 | 447 | * |
| donatien | 0:632c9925f013 | 448 | * @note This function only looks in the internal array of known |
| donatien | 0:632c9925f013 | 449 | * hostnames, it does not send out a query for the hostname if none |
| donatien | 0:632c9925f013 | 450 | * was found. The function dns_enqueue() can be used to send a query |
| donatien | 0:632c9925f013 | 451 | * for a hostname. |
| donatien | 0:632c9925f013 | 452 | * |
| donatien | 0:632c9925f013 | 453 | * @param name the hostname to look up |
| donatien | 0:632c9925f013 | 454 | * @return the hostname's IP address, as u32_t (instead of ip_addr_t to |
| donatien | 0:632c9925f013 | 455 | * better check for failure: != IPADDR_NONE) or IPADDR_NONE if the hostname |
| donatien | 0:632c9925f013 | 456 | * was not found in the cached dns_table. |
| donatien | 0:632c9925f013 | 457 | */ |
| donatien | 0:632c9925f013 | 458 | static u32_t |
| donatien | 0:632c9925f013 | 459 | dns_lookup(const char *name) |
| donatien | 0:632c9925f013 | 460 | { |
| donatien | 0:632c9925f013 | 461 | u8_t i; |
| donatien | 0:632c9925f013 | 462 | #if DNS_LOCAL_HOSTLIST || defined(DNS_LOOKUP_LOCAL_EXTERN) |
| donatien | 0:632c9925f013 | 463 | u32_t addr; |
| donatien | 0:632c9925f013 | 464 | #endif /* DNS_LOCAL_HOSTLIST || defined(DNS_LOOKUP_LOCAL_EXTERN) */ |
| donatien | 0:632c9925f013 | 465 | #if DNS_LOCAL_HOSTLIST |
| donatien | 0:632c9925f013 | 466 | if ((addr = dns_lookup_local(name)) != IPADDR_NONE) { |
| donatien | 0:632c9925f013 | 467 | return addr; |
| donatien | 0:632c9925f013 | 468 | } |
| donatien | 0:632c9925f013 | 469 | #endif /* DNS_LOCAL_HOSTLIST */ |
| donatien | 0:632c9925f013 | 470 | #ifdef DNS_LOOKUP_LOCAL_EXTERN |
| donatien | 0:632c9925f013 | 471 | if((addr = DNS_LOOKUP_LOCAL_EXTERN(name)) != IPADDR_NONE) { |
| donatien | 0:632c9925f013 | 472 | return addr; |
| donatien | 0:632c9925f013 | 473 | } |
| donatien | 0:632c9925f013 | 474 | #endif /* DNS_LOOKUP_LOCAL_EXTERN */ |
| donatien | 0:632c9925f013 | 475 | |
| donatien | 0:632c9925f013 | 476 | /* Walk through name list, return entry if found. If not, return NULL. */ |
| donatien | 0:632c9925f013 | 477 | for (i = 0; i < DNS_TABLE_SIZE; ++i) { |
| donatien | 0:632c9925f013 | 478 | if ((dns_table[i].state == DNS_STATE_DONE) && |
| donatien | 0:632c9925f013 | 479 | (strcmp(name, dns_table[i].name) == 0)) { |
| donatien | 0:632c9925f013 | 480 | LWIP_DEBUGF(DNS_DEBUG, ("dns_lookup: \"%s\": found = ", name)); |
| donatien | 0:632c9925f013 | 481 | ip_addr_debug_print(DNS_DEBUG, &(dns_table[i].ipaddr)); |
| donatien | 0:632c9925f013 | 482 | LWIP_DEBUGF(DNS_DEBUG, ("\n")); |
| donatien | 0:632c9925f013 | 483 | return ip4_addr_get_u32(&dns_table[i].ipaddr); |
| donatien | 0:632c9925f013 | 484 | } |
| donatien | 0:632c9925f013 | 485 | } |
| donatien | 0:632c9925f013 | 486 | |
| donatien | 0:632c9925f013 | 487 | return IPADDR_NONE; |
| donatien | 0:632c9925f013 | 488 | } |
| donatien | 0:632c9925f013 | 489 | |
| donatien | 0:632c9925f013 | 490 | #if DNS_DOES_NAME_CHECK |
| donatien | 0:632c9925f013 | 491 | /** |
| donatien | 0:632c9925f013 | 492 | * Compare the "dotted" name "query" with the encoded name "response" |
| donatien | 0:632c9925f013 | 493 | * to make sure an answer from the DNS server matches the current dns_table |
| donatien | 0:632c9925f013 | 494 | * entry (otherwise, answers might arrive late for hostname not on the list |
| donatien | 0:632c9925f013 | 495 | * any more). |
| donatien | 0:632c9925f013 | 496 | * |
| donatien | 0:632c9925f013 | 497 | * @param query hostname (not encoded) from the dns_table |
| donatien | 0:632c9925f013 | 498 | * @param response encoded hostname in the DNS response |
| donatien | 0:632c9925f013 | 499 | * @return 0: names equal; 1: names differ |
| donatien | 0:632c9925f013 | 500 | */ |
| donatien | 0:632c9925f013 | 501 | static u8_t |
| donatien | 0:632c9925f013 | 502 | dns_compare_name(unsigned char *query, unsigned char *response) |
| donatien | 0:632c9925f013 | 503 | { |
| donatien | 0:632c9925f013 | 504 | unsigned char n; |
| donatien | 0:632c9925f013 | 505 | |
| donatien | 0:632c9925f013 | 506 | do { |
| donatien | 0:632c9925f013 | 507 | n = *response++; |
| donatien | 0:632c9925f013 | 508 | /** @see RFC 1035 - 4.1.4. Message compression */ |
| donatien | 0:632c9925f013 | 509 | if ((n & 0xc0) == 0xc0) { |
| donatien | 0:632c9925f013 | 510 | /* Compressed name */ |
| donatien | 0:632c9925f013 | 511 | break; |
| donatien | 0:632c9925f013 | 512 | } else { |
| donatien | 0:632c9925f013 | 513 | /* Not compressed name */ |
| donatien | 0:632c9925f013 | 514 | while (n > 0) { |
| donatien | 0:632c9925f013 | 515 | if ((*query) != (*response)) { |
| donatien | 0:632c9925f013 | 516 | return 1; |
| donatien | 0:632c9925f013 | 517 | } |
| donatien | 0:632c9925f013 | 518 | ++response; |
| donatien | 0:632c9925f013 | 519 | ++query; |
| donatien | 0:632c9925f013 | 520 | --n; |
| donatien | 0:632c9925f013 | 521 | }; |
| donatien | 0:632c9925f013 | 522 | ++query; |
| donatien | 0:632c9925f013 | 523 | } |
| donatien | 0:632c9925f013 | 524 | } while (*response != 0); |
| donatien | 0:632c9925f013 | 525 | |
| donatien | 0:632c9925f013 | 526 | return 0; |
| donatien | 0:632c9925f013 | 527 | } |
| donatien | 0:632c9925f013 | 528 | #endif /* DNS_DOES_NAME_CHECK */ |
| donatien | 0:632c9925f013 | 529 | |
| donatien | 0:632c9925f013 | 530 | /** |
| donatien | 0:632c9925f013 | 531 | * Walk through a compact encoded DNS name and return the end of the name. |
| donatien | 0:632c9925f013 | 532 | * |
| donatien | 0:632c9925f013 | 533 | * @param query encoded DNS name in the DNS server response |
| donatien | 0:632c9925f013 | 534 | * @return end of the name |
| donatien | 0:632c9925f013 | 535 | */ |
| donatien | 0:632c9925f013 | 536 | static unsigned char * |
| donatien | 0:632c9925f013 | 537 | dns_parse_name(unsigned char *query) |
| donatien | 0:632c9925f013 | 538 | { |
| donatien | 0:632c9925f013 | 539 | unsigned char n; |
| donatien | 0:632c9925f013 | 540 | |
| donatien | 0:632c9925f013 | 541 | do { |
| donatien | 0:632c9925f013 | 542 | n = *query++; |
| donatien | 0:632c9925f013 | 543 | /** @see RFC 1035 - 4.1.4. Message compression */ |
| donatien | 0:632c9925f013 | 544 | if ((n & 0xc0) == 0xc0) { |
| donatien | 0:632c9925f013 | 545 | /* Compressed name */ |
| donatien | 0:632c9925f013 | 546 | break; |
| donatien | 0:632c9925f013 | 547 | } else { |
| donatien | 0:632c9925f013 | 548 | /* Not compressed name */ |
| donatien | 0:632c9925f013 | 549 | while (n > 0) { |
| donatien | 0:632c9925f013 | 550 | ++query; |
| donatien | 0:632c9925f013 | 551 | --n; |
| donatien | 0:632c9925f013 | 552 | }; |
| donatien | 0:632c9925f013 | 553 | } |
| donatien | 0:632c9925f013 | 554 | } while (*query != 0); |
| donatien | 0:632c9925f013 | 555 | |
| donatien | 0:632c9925f013 | 556 | return query + 1; |
| donatien | 0:632c9925f013 | 557 | } |
| donatien | 0:632c9925f013 | 558 | |
| donatien | 0:632c9925f013 | 559 | /** |
| donatien | 0:632c9925f013 | 560 | * Send a DNS query packet. |
| donatien | 0:632c9925f013 | 561 | * |
| donatien | 0:632c9925f013 | 562 | * @param numdns index of the DNS server in the dns_servers table |
| donatien | 0:632c9925f013 | 563 | * @param name hostname to query |
| donatien | 0:632c9925f013 | 564 | * @param id index of the hostname in dns_table, used as transaction ID in the |
| donatien | 0:632c9925f013 | 565 | * DNS query packet |
| donatien | 0:632c9925f013 | 566 | * @return ERR_OK if packet is sent; an err_t indicating the problem otherwise |
| donatien | 0:632c9925f013 | 567 | */ |
| donatien | 0:632c9925f013 | 568 | static err_t |
| donatien | 0:632c9925f013 | 569 | dns_send(u8_t numdns, const char* name, u8_t id) |
| donatien | 0:632c9925f013 | 570 | { |
| donatien | 0:632c9925f013 | 571 | err_t err; |
| donatien | 0:632c9925f013 | 572 | struct dns_hdr *hdr; |
| donatien | 0:632c9925f013 | 573 | struct dns_query qry; |
| donatien | 0:632c9925f013 | 574 | struct pbuf *p; |
| donatien | 0:632c9925f013 | 575 | char *query, *nptr; |
| donatien | 0:632c9925f013 | 576 | const char *pHostname; |
| donatien | 0:632c9925f013 | 577 | u8_t n; |
| donatien | 0:632c9925f013 | 578 | |
| donatien | 0:632c9925f013 | 579 | LWIP_DEBUGF(DNS_DEBUG, ("dns_send: dns_servers[%"U16_F"] \"%s\": request\n", |
| donatien | 0:632c9925f013 | 580 | (u16_t)(numdns), name)); |
| donatien | 0:632c9925f013 | 581 | LWIP_ASSERT("dns server out of array", numdns < DNS_MAX_SERVERS); |
| donatien | 0:632c9925f013 | 582 | LWIP_ASSERT("dns server has no IP address set", !ip_addr_isany(&dns_servers[numdns])); |
| donatien | 0:632c9925f013 | 583 | |
| donatien | 0:632c9925f013 | 584 | /* if here, we have either a new query or a retry on a previous query to process */ |
| donatien | 0:632c9925f013 | 585 | p = pbuf_alloc(PBUF_TRANSPORT, SIZEOF_DNS_HDR + DNS_MAX_NAME_LENGTH + |
| donatien | 0:632c9925f013 | 586 | SIZEOF_DNS_QUERY, PBUF_RAM); |
| donatien | 0:632c9925f013 | 587 | if (p != NULL) { |
| donatien | 0:632c9925f013 | 588 | LWIP_ASSERT("pbuf must be in one piece", p->next == NULL); |
| donatien | 0:632c9925f013 | 589 | /* fill dns header */ |
| donatien | 0:632c9925f013 | 590 | hdr = (struct dns_hdr*)p->payload; |
| donatien | 0:632c9925f013 | 591 | memset(hdr, 0, SIZEOF_DNS_HDR); |
| donatien | 0:632c9925f013 | 592 | hdr->id = htons(id); |
| donatien | 0:632c9925f013 | 593 | hdr->flags1 = DNS_FLAG1_RD; |
| donatien | 0:632c9925f013 | 594 | hdr->numquestions = htons(1); |
| donatien | 0:632c9925f013 | 595 | query = (char*)hdr + SIZEOF_DNS_HDR; |
| donatien | 0:632c9925f013 | 596 | pHostname = name; |
| donatien | 0:632c9925f013 | 597 | --pHostname; |
| donatien | 0:632c9925f013 | 598 | |
| donatien | 0:632c9925f013 | 599 | /* convert hostname into suitable query format. */ |
| donatien | 0:632c9925f013 | 600 | do { |
| donatien | 0:632c9925f013 | 601 | ++pHostname; |
| donatien | 0:632c9925f013 | 602 | nptr = query; |
| donatien | 0:632c9925f013 | 603 | ++query; |
| donatien | 0:632c9925f013 | 604 | for(n = 0; *pHostname != '.' && *pHostname != 0; ++pHostname) { |
| donatien | 0:632c9925f013 | 605 | *query = *pHostname; |
| donatien | 0:632c9925f013 | 606 | ++query; |
| donatien | 0:632c9925f013 | 607 | ++n; |
| donatien | 0:632c9925f013 | 608 | } |
| donatien | 0:632c9925f013 | 609 | *nptr = n; |
| donatien | 0:632c9925f013 | 610 | } while(*pHostname != 0); |
| donatien | 0:632c9925f013 | 611 | *query++='\0'; |
| donatien | 0:632c9925f013 | 612 | |
| donatien | 0:632c9925f013 | 613 | /* fill dns query */ |
| donatien | 0:632c9925f013 | 614 | qry.type = htons(DNS_RRTYPE_A); |
| donatien | 0:632c9925f013 | 615 | qry.cls = htons(DNS_RRCLASS_IN); |
| donatien | 0:632c9925f013 | 616 | SMEMCPY(query, &qry, SIZEOF_DNS_QUERY); |
| donatien | 0:632c9925f013 | 617 | |
| donatien | 0:632c9925f013 | 618 | /* resize pbuf to the exact dns query */ |
| donatien | 0:632c9925f013 | 619 | pbuf_realloc(p, (u16_t)((query + SIZEOF_DNS_QUERY) - ((char*)(p->payload)))); |
| donatien | 0:632c9925f013 | 620 | |
| donatien | 0:632c9925f013 | 621 | /* connect to the server for faster receiving */ |
| donatien | 0:632c9925f013 | 622 | udp_connect(dns_pcb, &dns_servers[numdns], DNS_SERVER_PORT); |
| donatien | 0:632c9925f013 | 623 | /* send dns packet */ |
| donatien | 0:632c9925f013 | 624 | err = udp_sendto(dns_pcb, p, &dns_servers[numdns], DNS_SERVER_PORT); |
| donatien | 0:632c9925f013 | 625 | |
| donatien | 0:632c9925f013 | 626 | /* free pbuf */ |
| donatien | 0:632c9925f013 | 627 | pbuf_free(p); |
| donatien | 0:632c9925f013 | 628 | } else { |
| donatien | 0:632c9925f013 | 629 | err = ERR_MEM; |
| donatien | 0:632c9925f013 | 630 | } |
| donatien | 0:632c9925f013 | 631 | |
| donatien | 0:632c9925f013 | 632 | return err; |
| donatien | 0:632c9925f013 | 633 | } |
| donatien | 0:632c9925f013 | 634 | |
| donatien | 0:632c9925f013 | 635 | /** |
| donatien | 0:632c9925f013 | 636 | * dns_check_entry() - see if pEntry has not yet been queried and, if so, sends out a query. |
| donatien | 0:632c9925f013 | 637 | * Check an entry in the dns_table: |
| donatien | 0:632c9925f013 | 638 | * - send out query for new entries |
| donatien | 0:632c9925f013 | 639 | * - retry old pending entries on timeout (also with different servers) |
| donatien | 0:632c9925f013 | 640 | * - remove completed entries from the table if their TTL has expired |
| donatien | 0:632c9925f013 | 641 | * |
| donatien | 0:632c9925f013 | 642 | * @param i index of the dns_table entry to check |
| donatien | 0:632c9925f013 | 643 | */ |
| donatien | 0:632c9925f013 | 644 | static void |
| donatien | 0:632c9925f013 | 645 | dns_check_entry(u8_t i) |
| donatien | 0:632c9925f013 | 646 | { |
| donatien | 0:632c9925f013 | 647 | struct dns_table_entry *pEntry = &dns_table[i]; |
| donatien | 0:632c9925f013 | 648 | |
| donatien | 0:632c9925f013 | 649 | LWIP_ASSERT("array index out of bounds", i < DNS_TABLE_SIZE); |
| donatien | 0:632c9925f013 | 650 | |
| donatien | 0:632c9925f013 | 651 | switch(pEntry->state) { |
| donatien | 0:632c9925f013 | 652 | |
| donatien | 0:632c9925f013 | 653 | case DNS_STATE_NEW: { |
| donatien | 0:632c9925f013 | 654 | /* initialize new entry */ |
| donatien | 0:632c9925f013 | 655 | pEntry->state = DNS_STATE_ASKING; |
| donatien | 0:632c9925f013 | 656 | pEntry->numdns = 0; |
| donatien | 0:632c9925f013 | 657 | pEntry->tmr = 1; |
| donatien | 0:632c9925f013 | 658 | pEntry->retries = 0; |
| donatien | 0:632c9925f013 | 659 | |
| donatien | 0:632c9925f013 | 660 | /* send DNS packet for this entry */ |
| donatien | 0:632c9925f013 | 661 | dns_send(pEntry->numdns, pEntry->name, i); |
| donatien | 0:632c9925f013 | 662 | break; |
| donatien | 0:632c9925f013 | 663 | } |
| donatien | 0:632c9925f013 | 664 | |
| donatien | 0:632c9925f013 | 665 | case DNS_STATE_ASKING: { |
| donatien | 0:632c9925f013 | 666 | if (--pEntry->tmr == 0) { |
| donatien | 0:632c9925f013 | 667 | if (++pEntry->retries == DNS_MAX_RETRIES) { |
| donatien | 0:632c9925f013 | 668 | if ((pEntry->numdns+1<DNS_MAX_SERVERS) && !ip_addr_isany(&dns_servers[pEntry->numdns+1])) { |
| donatien | 0:632c9925f013 | 669 | /* change of server */ |
| donatien | 0:632c9925f013 | 670 | pEntry->numdns++; |
| donatien | 0:632c9925f013 | 671 | pEntry->tmr = 1; |
| donatien | 0:632c9925f013 | 672 | pEntry->retries = 0; |
| donatien | 0:632c9925f013 | 673 | break; |
| donatien | 0:632c9925f013 | 674 | } else { |
| donatien | 0:632c9925f013 | 675 | LWIP_DEBUGF(DNS_DEBUG, ("dns_check_entry: \"%s\": timeout\n", pEntry->name)); |
| donatien | 0:632c9925f013 | 676 | /* call specified callback function if provided */ |
| donatien | 0:632c9925f013 | 677 | if (pEntry->found) |
| donatien | 0:632c9925f013 | 678 | (*pEntry->found)(pEntry->name, NULL, pEntry->arg); |
| donatien | 0:632c9925f013 | 679 | /* flush this entry */ |
| donatien | 0:632c9925f013 | 680 | pEntry->state = DNS_STATE_UNUSED; |
| donatien | 0:632c9925f013 | 681 | pEntry->found = NULL; |
| donatien | 0:632c9925f013 | 682 | break; |
| donatien | 0:632c9925f013 | 683 | } |
| donatien | 0:632c9925f013 | 684 | } |
| donatien | 0:632c9925f013 | 685 | |
| donatien | 0:632c9925f013 | 686 | /* wait longer for the next retry */ |
| donatien | 0:632c9925f013 | 687 | pEntry->tmr = pEntry->retries; |
| donatien | 0:632c9925f013 | 688 | |
| donatien | 0:632c9925f013 | 689 | /* send DNS packet for this entry */ |
| donatien | 0:632c9925f013 | 690 | dns_send(pEntry->numdns, pEntry->name, i); |
| donatien | 0:632c9925f013 | 691 | } |
| donatien | 0:632c9925f013 | 692 | break; |
| donatien | 0:632c9925f013 | 693 | } |
| donatien | 0:632c9925f013 | 694 | |
| donatien | 0:632c9925f013 | 695 | case DNS_STATE_DONE: { |
| donatien | 0:632c9925f013 | 696 | /* if the time to live is nul */ |
| donatien | 0:632c9925f013 | 697 | if (--pEntry->ttl == 0) { |
| donatien | 0:632c9925f013 | 698 | LWIP_DEBUGF(DNS_DEBUG, ("dns_check_entry: \"%s\": flush\n", pEntry->name)); |
| donatien | 0:632c9925f013 | 699 | /* flush this entry */ |
| donatien | 0:632c9925f013 | 700 | pEntry->state = DNS_STATE_UNUSED; |
| donatien | 0:632c9925f013 | 701 | pEntry->found = NULL; |
| donatien | 0:632c9925f013 | 702 | } |
| donatien | 0:632c9925f013 | 703 | break; |
| donatien | 0:632c9925f013 | 704 | } |
| donatien | 0:632c9925f013 | 705 | case DNS_STATE_UNUSED: |
| donatien | 0:632c9925f013 | 706 | /* nothing to do */ |
| donatien | 0:632c9925f013 | 707 | break; |
| donatien | 0:632c9925f013 | 708 | default: |
| donatien | 0:632c9925f013 | 709 | LWIP_ASSERT("unknown dns_table entry state:", 0); |
| donatien | 0:632c9925f013 | 710 | break; |
| donatien | 0:632c9925f013 | 711 | } |
| donatien | 0:632c9925f013 | 712 | } |
| donatien | 0:632c9925f013 | 713 | |
| donatien | 0:632c9925f013 | 714 | /** |
| donatien | 0:632c9925f013 | 715 | * Call dns_check_entry for each entry in dns_table - check all entries. |
| donatien | 0:632c9925f013 | 716 | */ |
| donatien | 0:632c9925f013 | 717 | static void |
| donatien | 0:632c9925f013 | 718 | dns_check_entries(void) |
| donatien | 0:632c9925f013 | 719 | { |
| donatien | 0:632c9925f013 | 720 | u8_t i; |
| donatien | 0:632c9925f013 | 721 | |
| donatien | 0:632c9925f013 | 722 | for (i = 0; i < DNS_TABLE_SIZE; ++i) { |
| donatien | 0:632c9925f013 | 723 | dns_check_entry(i); |
| donatien | 0:632c9925f013 | 724 | } |
| donatien | 0:632c9925f013 | 725 | } |
| donatien | 0:632c9925f013 | 726 | |
| donatien | 0:632c9925f013 | 727 | /** |
| donatien | 0:632c9925f013 | 728 | * Receive input function for DNS response packets arriving for the dns UDP pcb. |
| donatien | 0:632c9925f013 | 729 | * |
| donatien | 0:632c9925f013 | 730 | * @params see udp.h |
| donatien | 0:632c9925f013 | 731 | */ |
| donatien | 0:632c9925f013 | 732 | static void |
| donatien | 0:632c9925f013 | 733 | dns_recv(void *arg, struct udp_pcb *pcb, struct pbuf *p, ip_addr_t *addr, u16_t port) |
| donatien | 0:632c9925f013 | 734 | { |
| donatien | 0:632c9925f013 | 735 | u16_t i; |
| donatien | 0:632c9925f013 | 736 | char *pHostname; |
| donatien | 0:632c9925f013 | 737 | struct dns_hdr *hdr; |
| donatien | 0:632c9925f013 | 738 | struct dns_answer ans; |
| donatien | 0:632c9925f013 | 739 | struct dns_table_entry *pEntry; |
| donatien | 0:632c9925f013 | 740 | u16_t nquestions, nanswers; |
| donatien | 0:632c9925f013 | 741 | |
| donatien | 0:632c9925f013 | 742 | LWIP_UNUSED_ARG(arg); |
| donatien | 0:632c9925f013 | 743 | LWIP_UNUSED_ARG(pcb); |
| donatien | 0:632c9925f013 | 744 | LWIP_UNUSED_ARG(addr); |
| donatien | 0:632c9925f013 | 745 | LWIP_UNUSED_ARG(port); |
| donatien | 0:632c9925f013 | 746 | |
| donatien | 0:632c9925f013 | 747 | /* is the dns message too big ? */ |
| donatien | 0:632c9925f013 | 748 | if (p->tot_len > DNS_MSG_SIZE) { |
| donatien | 0:632c9925f013 | 749 | LWIP_DEBUGF(DNS_DEBUG, ("dns_recv: pbuf too big\n")); |
| donatien | 0:632c9925f013 | 750 | /* free pbuf and return */ |
| donatien | 0:632c9925f013 | 751 | goto memerr; |
| donatien | 0:632c9925f013 | 752 | } |
| donatien | 0:632c9925f013 | 753 | |
| donatien | 0:632c9925f013 | 754 | /* is the dns message big enough ? */ |
| donatien | 0:632c9925f013 | 755 | if (p->tot_len < (SIZEOF_DNS_HDR + SIZEOF_DNS_QUERY + SIZEOF_DNS_ANSWER)) { |
| donatien | 0:632c9925f013 | 756 | LWIP_DEBUGF(DNS_DEBUG, ("dns_recv: pbuf too small\n")); |
| donatien | 0:632c9925f013 | 757 | /* free pbuf and return */ |
| donatien | 0:632c9925f013 | 758 | goto memerr; |
| donatien | 0:632c9925f013 | 759 | } |
| donatien | 0:632c9925f013 | 760 | |
| donatien | 0:632c9925f013 | 761 | /* copy dns payload inside static buffer for processing */ |
| donatien | 0:632c9925f013 | 762 | if (pbuf_copy_partial(p, dns_payload, p->tot_len, 0) == p->tot_len) { |
| donatien | 0:632c9925f013 | 763 | /* The ID in the DNS header should be our entry into the name table. */ |
| donatien | 0:632c9925f013 | 764 | hdr = (struct dns_hdr*)dns_payload; |
| donatien | 0:632c9925f013 | 765 | i = htons(hdr->id); |
| donatien | 0:632c9925f013 | 766 | if (i < DNS_TABLE_SIZE) { |
| donatien | 0:632c9925f013 | 767 | pEntry = &dns_table[i]; |
| donatien | 0:632c9925f013 | 768 | if(pEntry->state == DNS_STATE_ASKING) { |
| donatien | 0:632c9925f013 | 769 | /* This entry is now completed. */ |
| donatien | 0:632c9925f013 | 770 | pEntry->state = DNS_STATE_DONE; |
| donatien | 0:632c9925f013 | 771 | pEntry->err = hdr->flags2 & DNS_FLAG2_ERR_MASK; |
| donatien | 0:632c9925f013 | 772 | |
| donatien | 0:632c9925f013 | 773 | /* We only care about the question(s) and the answers. The authrr |
| donatien | 0:632c9925f013 | 774 | and the extrarr are simply discarded. */ |
| donatien | 0:632c9925f013 | 775 | nquestions = htons(hdr->numquestions); |
| donatien | 0:632c9925f013 | 776 | nanswers = htons(hdr->numanswers); |
| donatien | 0:632c9925f013 | 777 | |
| donatien | 0:632c9925f013 | 778 | /* Check for error. If so, call callback to inform. */ |
| donatien | 0:632c9925f013 | 779 | if (((hdr->flags1 & DNS_FLAG1_RESPONSE) == 0) || (pEntry->err != 0) || (nquestions != 1)) { |
| donatien | 0:632c9925f013 | 780 | LWIP_DEBUGF(DNS_DEBUG, ("dns_recv: \"%s\": error in flags\n", pEntry->name)); |
| donatien | 0:632c9925f013 | 781 | /* call callback to indicate error, clean up memory and return */ |
| donatien | 0:632c9925f013 | 782 | goto responseerr; |
| donatien | 0:632c9925f013 | 783 | } |
| donatien | 0:632c9925f013 | 784 | |
| donatien | 0:632c9925f013 | 785 | #if DNS_DOES_NAME_CHECK |
| donatien | 0:632c9925f013 | 786 | /* Check if the name in the "question" part match with the name in the entry. */ |
| donatien | 0:632c9925f013 | 787 | if (dns_compare_name((unsigned char *)(pEntry->name), (unsigned char *)dns_payload + SIZEOF_DNS_HDR) != 0) { |
| donatien | 0:632c9925f013 | 788 | LWIP_DEBUGF(DNS_DEBUG, ("dns_recv: \"%s\": response not match to query\n", pEntry->name)); |
| donatien | 0:632c9925f013 | 789 | /* call callback to indicate error, clean up memory and return */ |
| donatien | 0:632c9925f013 | 790 | goto responseerr; |
| donatien | 0:632c9925f013 | 791 | } |
| donatien | 0:632c9925f013 | 792 | #endif /* DNS_DOES_NAME_CHECK */ |
| donatien | 0:632c9925f013 | 793 | |
| donatien | 0:632c9925f013 | 794 | /* Skip the name in the "question" part */ |
| donatien | 0:632c9925f013 | 795 | pHostname = (char *) dns_parse_name((unsigned char *)dns_payload + SIZEOF_DNS_HDR) + SIZEOF_DNS_QUERY; |
| donatien | 0:632c9925f013 | 796 | |
| donatien | 0:632c9925f013 | 797 | while (nanswers > 0) { |
| donatien | 0:632c9925f013 | 798 | /* skip answer resource record's host name */ |
| donatien | 0:632c9925f013 | 799 | pHostname = (char *) dns_parse_name((unsigned char *)pHostname); |
| donatien | 0:632c9925f013 | 800 | |
| donatien | 0:632c9925f013 | 801 | /* Check for IP address type and Internet class. Others are discarded. */ |
| donatien | 0:632c9925f013 | 802 | SMEMCPY(&ans, pHostname, SIZEOF_DNS_ANSWER); |
| donatien | 0:632c9925f013 | 803 | if((ans.type == htons(DNS_RRTYPE_A)) && (ans.cls == htons(DNS_RRCLASS_IN)) && |
| donatien | 0:632c9925f013 | 804 | (ans.len == htons(sizeof(ip_addr_t))) ) { |
| donatien | 0:632c9925f013 | 805 | /* read the answer resource record's TTL, and maximize it if needed */ |
| donatien | 0:632c9925f013 | 806 | pEntry->ttl = ntohl(ans.ttl); |
| donatien | 0:632c9925f013 | 807 | if (pEntry->ttl > DNS_MAX_TTL) { |
| donatien | 0:632c9925f013 | 808 | pEntry->ttl = DNS_MAX_TTL; |
| donatien | 0:632c9925f013 | 809 | } |
| donatien | 0:632c9925f013 | 810 | /* read the IP address after answer resource record's header */ |
| donatien | 0:632c9925f013 | 811 | SMEMCPY(&(pEntry->ipaddr), (pHostname+SIZEOF_DNS_ANSWER), sizeof(ip_addr_t)); |
| donatien | 0:632c9925f013 | 812 | LWIP_DEBUGF(DNS_DEBUG, ("dns_recv: \"%s\": response = ", pEntry->name)); |
| donatien | 0:632c9925f013 | 813 | ip_addr_debug_print(DNS_DEBUG, (&(pEntry->ipaddr))); |
| donatien | 0:632c9925f013 | 814 | LWIP_DEBUGF(DNS_DEBUG, ("\n")); |
| donatien | 0:632c9925f013 | 815 | /* call specified callback function if provided */ |
| donatien | 0:632c9925f013 | 816 | if (pEntry->found) { |
| donatien | 0:632c9925f013 | 817 | (*pEntry->found)(pEntry->name, &pEntry->ipaddr, pEntry->arg); |
| donatien | 0:632c9925f013 | 818 | } |
| donatien | 0:632c9925f013 | 819 | /* deallocate memory and return */ |
| donatien | 0:632c9925f013 | 820 | goto memerr; |
| donatien | 0:632c9925f013 | 821 | } else { |
| donatien | 0:632c9925f013 | 822 | pHostname = pHostname + SIZEOF_DNS_ANSWER + htons(ans.len); |
| donatien | 0:632c9925f013 | 823 | } |
| donatien | 0:632c9925f013 | 824 | --nanswers; |
| donatien | 0:632c9925f013 | 825 | } |
| donatien | 0:632c9925f013 | 826 | LWIP_DEBUGF(DNS_DEBUG, ("dns_recv: \"%s\": error in response\n", pEntry->name)); |
| donatien | 0:632c9925f013 | 827 | /* call callback to indicate error, clean up memory and return */ |
| donatien | 0:632c9925f013 | 828 | goto responseerr; |
| donatien | 0:632c9925f013 | 829 | } |
| donatien | 0:632c9925f013 | 830 | } |
| donatien | 0:632c9925f013 | 831 | } |
| donatien | 0:632c9925f013 | 832 | |
| donatien | 0:632c9925f013 | 833 | /* deallocate memory and return */ |
| donatien | 0:632c9925f013 | 834 | goto memerr; |
| donatien | 0:632c9925f013 | 835 | |
| donatien | 0:632c9925f013 | 836 | responseerr: |
| donatien | 0:632c9925f013 | 837 | /* ERROR: call specified callback function with NULL as name to indicate an error */ |
| donatien | 0:632c9925f013 | 838 | if (pEntry->found) { |
| donatien | 0:632c9925f013 | 839 | (*pEntry->found)(pEntry->name, NULL, pEntry->arg); |
| donatien | 0:632c9925f013 | 840 | } |
| donatien | 0:632c9925f013 | 841 | /* flush this entry */ |
| donatien | 0:632c9925f013 | 842 | pEntry->state = DNS_STATE_UNUSED; |
| donatien | 0:632c9925f013 | 843 | pEntry->found = NULL; |
| donatien | 0:632c9925f013 | 844 | |
| donatien | 0:632c9925f013 | 845 | memerr: |
| donatien | 0:632c9925f013 | 846 | /* free pbuf */ |
| donatien | 0:632c9925f013 | 847 | pbuf_free(p); |
| donatien | 0:632c9925f013 | 848 | return; |
| donatien | 0:632c9925f013 | 849 | } |
| donatien | 0:632c9925f013 | 850 | |
| donatien | 0:632c9925f013 | 851 | /** |
| donatien | 0:632c9925f013 | 852 | * Queues a new hostname to resolve and sends out a DNS query for that hostname |
| donatien | 0:632c9925f013 | 853 | * |
| donatien | 0:632c9925f013 | 854 | * @param name the hostname that is to be queried |
| donatien | 0:632c9925f013 | 855 | * @param found a callback founction to be called on success, failure or timeout |
| donatien | 0:632c9925f013 | 856 | * @param callback_arg argument to pass to the callback function |
| donatien | 0:632c9925f013 | 857 | * @return @return a err_t return code. |
| donatien | 0:632c9925f013 | 858 | */ |
| donatien | 0:632c9925f013 | 859 | static err_t |
| donatien | 0:632c9925f013 | 860 | dns_enqueue(const char *name, dns_found_callback found, void *callback_arg) |
| donatien | 0:632c9925f013 | 861 | { |
| donatien | 0:632c9925f013 | 862 | u8_t i; |
| donatien | 0:632c9925f013 | 863 | u8_t lseq, lseqi; |
| donatien | 0:632c9925f013 | 864 | struct dns_table_entry *pEntry = NULL; |
| donatien | 0:632c9925f013 | 865 | size_t namelen; |
| donatien | 0:632c9925f013 | 866 | |
| donatien | 0:632c9925f013 | 867 | /* search an unused entry, or the oldest one */ |
| donatien | 0:632c9925f013 | 868 | lseq = lseqi = 0; |
| donatien | 0:632c9925f013 | 869 | for (i = 0; i < DNS_TABLE_SIZE; ++i) { |
| donatien | 0:632c9925f013 | 870 | pEntry = &dns_table[i]; |
| donatien | 0:632c9925f013 | 871 | /* is it an unused entry ? */ |
| donatien | 0:632c9925f013 | 872 | if (pEntry->state == DNS_STATE_UNUSED) |
| donatien | 0:632c9925f013 | 873 | break; |
| donatien | 0:632c9925f013 | 874 | |
| donatien | 0:632c9925f013 | 875 | /* check if this is the oldest completed entry */ |
| donatien | 0:632c9925f013 | 876 | if (pEntry->state == DNS_STATE_DONE) { |
| donatien | 0:632c9925f013 | 877 | if ((dns_seqno - pEntry->seqno) > lseq) { |
| donatien | 0:632c9925f013 | 878 | lseq = dns_seqno - pEntry->seqno; |
| donatien | 0:632c9925f013 | 879 | lseqi = i; |
| donatien | 0:632c9925f013 | 880 | } |
| donatien | 0:632c9925f013 | 881 | } |
| donatien | 0:632c9925f013 | 882 | } |
| donatien | 0:632c9925f013 | 883 | |
| donatien | 0:632c9925f013 | 884 | /* if we don't have found an unused entry, use the oldest completed one */ |
| donatien | 0:632c9925f013 | 885 | if (i == DNS_TABLE_SIZE) { |
| donatien | 0:632c9925f013 | 886 | if ((lseqi >= DNS_TABLE_SIZE) || (dns_table[lseqi].state != DNS_STATE_DONE)) { |
| donatien | 0:632c9925f013 | 887 | /* no entry can't be used now, table is full */ |
| donatien | 0:632c9925f013 | 888 | LWIP_DEBUGF(DNS_DEBUG, ("dns_enqueue: \"%s\": DNS entries table is full\n", name)); |
| donatien | 0:632c9925f013 | 889 | return ERR_MEM; |
| donatien | 0:632c9925f013 | 890 | } else { |
| donatien | 0:632c9925f013 | 891 | /* use the oldest completed one */ |
| donatien | 0:632c9925f013 | 892 | i = lseqi; |
| donatien | 0:632c9925f013 | 893 | pEntry = &dns_table[i]; |
| donatien | 0:632c9925f013 | 894 | } |
| donatien | 0:632c9925f013 | 895 | } |
| donatien | 0:632c9925f013 | 896 | |
| donatien | 0:632c9925f013 | 897 | /* use this entry */ |
| donatien | 0:632c9925f013 | 898 | LWIP_DEBUGF(DNS_DEBUG, ("dns_enqueue: \"%s\": use DNS entry %"U16_F"\n", name, (u16_t)(i))); |
| donatien | 0:632c9925f013 | 899 | |
| donatien | 0:632c9925f013 | 900 | /* fill the entry */ |
| donatien | 0:632c9925f013 | 901 | pEntry->state = DNS_STATE_NEW; |
| donatien | 0:632c9925f013 | 902 | pEntry->seqno = dns_seqno++; |
| donatien | 0:632c9925f013 | 903 | pEntry->found = found; |
| donatien | 0:632c9925f013 | 904 | pEntry->arg = callback_arg; |
| donatien | 0:632c9925f013 | 905 | namelen = LWIP_MIN(strlen(name), DNS_MAX_NAME_LENGTH-1); |
| donatien | 0:632c9925f013 | 906 | MEMCPY(pEntry->name, name, namelen); |
| donatien | 0:632c9925f013 | 907 | pEntry->name[namelen] = 0; |
| donatien | 0:632c9925f013 | 908 | |
| donatien | 0:632c9925f013 | 909 | /* force to send query without waiting timer */ |
| donatien | 0:632c9925f013 | 910 | dns_check_entry(i); |
| donatien | 0:632c9925f013 | 911 | |
| donatien | 0:632c9925f013 | 912 | /* dns query is enqueued */ |
| donatien | 0:632c9925f013 | 913 | return ERR_INPROGRESS; |
| donatien | 0:632c9925f013 | 914 | } |
| donatien | 0:632c9925f013 | 915 | |
| donatien | 0:632c9925f013 | 916 | /** |
| donatien | 0:632c9925f013 | 917 | * Resolve a hostname (string) into an IP address. |
| donatien | 0:632c9925f013 | 918 | * NON-BLOCKING callback version for use with raw API!!! |
| donatien | 0:632c9925f013 | 919 | * |
| donatien | 0:632c9925f013 | 920 | * Returns immediately with one of err_t return codes: |
| donatien | 0:632c9925f013 | 921 | * - ERR_OK if hostname is a valid IP address string or the host |
| donatien | 0:632c9925f013 | 922 | * name is already in the local names table. |
| donatien | 0:632c9925f013 | 923 | * - ERR_INPROGRESS enqueue a request to be sent to the DNS server |
| donatien | 0:632c9925f013 | 924 | * for resolution if no errors are present. |
| donatien | 0:632c9925f013 | 925 | * |
| donatien | 0:632c9925f013 | 926 | * @param hostname the hostname that is to be queried |
| donatien | 0:632c9925f013 | 927 | * @param addr pointer to a ip_addr_t where to store the address if it is already |
| donatien | 0:632c9925f013 | 928 | * cached in the dns_table (only valid if ERR_OK is returned!) |
| donatien | 0:632c9925f013 | 929 | * @param found a callback function to be called on success, failure or timeout (only if |
| donatien | 0:632c9925f013 | 930 | * ERR_INPROGRESS is returned!) |
| donatien | 0:632c9925f013 | 931 | * @param callback_arg argument to pass to the callback function |
| donatien | 0:632c9925f013 | 932 | * @return a err_t return code. |
| donatien | 0:632c9925f013 | 933 | */ |
| donatien | 0:632c9925f013 | 934 | err_t |
| donatien | 0:632c9925f013 | 935 | dns_gethostbyname(const char *hostname, ip_addr_t *addr, dns_found_callback found, |
| donatien | 0:632c9925f013 | 936 | void *callback_arg) |
| donatien | 0:632c9925f013 | 937 | { |
| donatien | 0:632c9925f013 | 938 | u32_t ipaddr; |
| donatien | 0:632c9925f013 | 939 | /* not initialized or no valid server yet, or invalid addr pointer |
| donatien | 0:632c9925f013 | 940 | * or invalid hostname or invalid hostname length */ |
| donatien | 0:632c9925f013 | 941 | if ((dns_pcb == NULL) || (addr == NULL) || |
| donatien | 0:632c9925f013 | 942 | (!hostname) || (!hostname[0]) || |
| donatien | 0:632c9925f013 | 943 | (strlen(hostname) >= DNS_MAX_NAME_LENGTH)) { |
| donatien | 0:632c9925f013 | 944 | return ERR_VAL; |
| donatien | 0:632c9925f013 | 945 | } |
| donatien | 0:632c9925f013 | 946 | |
| donatien | 0:632c9925f013 | 947 | #if LWIP_HAVE_LOOPIF |
| donatien | 0:632c9925f013 | 948 | if (strcmp(hostname, "localhost")==0) { |
| donatien | 0:632c9925f013 | 949 | ip_addr_set_loopback(addr); |
| donatien | 0:632c9925f013 | 950 | return ERR_OK; |
| donatien | 0:632c9925f013 | 951 | } |
| donatien | 0:632c9925f013 | 952 | #endif /* LWIP_HAVE_LOOPIF */ |
| donatien | 0:632c9925f013 | 953 | |
| donatien | 0:632c9925f013 | 954 | /* host name already in octet notation? set ip addr and return ERR_OK */ |
| donatien | 0:632c9925f013 | 955 | ipaddr = ipaddr_addr(hostname); |
| donatien | 0:632c9925f013 | 956 | if (ipaddr == IPADDR_NONE) { |
| donatien | 0:632c9925f013 | 957 | /* already have this address cached? */ |
| donatien | 0:632c9925f013 | 958 | ipaddr = dns_lookup(hostname); |
| donatien | 0:632c9925f013 | 959 | } |
| donatien | 0:632c9925f013 | 960 | if (ipaddr != IPADDR_NONE) { |
| donatien | 0:632c9925f013 | 961 | ip4_addr_set_u32(addr, ipaddr); |
| donatien | 0:632c9925f013 | 962 | return ERR_OK; |
| donatien | 0:632c9925f013 | 963 | } |
| donatien | 0:632c9925f013 | 964 | |
| donatien | 0:632c9925f013 | 965 | /* queue query with specified callback */ |
| donatien | 0:632c9925f013 | 966 | return dns_enqueue(hostname, found, callback_arg); |
| donatien | 0:632c9925f013 | 967 | } |
| donatien | 0:632c9925f013 | 968 | #endif /* LWIP_DNS */ |