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| <div id="projectname">lwIP |
|  <span id="projectnumber">2.1.2</span> |
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| <div id="projectbrief">Lightweight IP stack</div> |
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| <a href="#func-members">Functions</a> </div> |
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| <div class="title">DNS<div class="ingroups"><a class="el" href="group__api.html">APIs</a> » <a class="el" href="group__callbackstyle__api.html">"raw" APIs</a></div></div> </div> |
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| Functions</h2></td></tr> |
| <tr class="memitem:gaf66c5d8273f83cdc2cdd8911fb68d584"><td class="memItemLeft" align="right" valign="top">void </td><td class="memItemRight" valign="bottom"><a class="el" href="group__dns.html#gaf66c5d8273f83cdc2cdd8911fb68d584">dns_setserver</a> (u8_t numdns, const <a class="el" href="group__ipaddr.html#ga16ef96d6cde029029bbf47fee35fd67a">ip_addr_t</a> *dnsserver)</td></tr> |
| <tr class="separator:gaf66c5d8273f83cdc2cdd8911fb68d584"><td class="memSeparator" colspan="2"> </td></tr> |
| <tr class="memitem:gad02111a6b26b93f1c3580d5f41a59af3"><td class="memItemLeft" align="right" valign="top">const <a class="el" href="group__ipaddr.html#ga16ef96d6cde029029bbf47fee35fd67a">ip_addr_t</a> * </td><td class="memItemRight" valign="bottom"><a class="el" href="group__dns.html#gad02111a6b26b93f1c3580d5f41a59af3">dns_getserver</a> (u8_t numdns)</td></tr> |
| <tr class="separator:gad02111a6b26b93f1c3580d5f41a59af3"><td class="memSeparator" colspan="2"> </td></tr> |
| <tr class="memitem:ga1e040ec38166dc9bfcc3473aab0c799f"><td class="memItemLeft" align="right" valign="top"><a class="el" href="group__infrastructure__errors.html#gaf02d9da80fd66b4f986d2c53d7231ddb">err_t</a> </td><td class="memItemRight" valign="bottom"><a class="el" href="group__dns.html#ga1e040ec38166dc9bfcc3473aab0c799f">dns_gethostbyname</a> (const char *hostname, <a class="el" href="group__ipaddr.html#ga16ef96d6cde029029bbf47fee35fd67a">ip_addr_t</a> *addr, <a class="el" href="dns_8h.html#ab5a9dec5b22802f91876c53e99f427ae">dns_found_callback</a> found, void *callback_arg)</td></tr> |
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| <tr class="memitem:gae84449f60dca6b863142daca8e03ce79"><td class="memItemLeft" align="right" valign="top"><a class="el" href="group__infrastructure__errors.html#gaf02d9da80fd66b4f986d2c53d7231ddb">err_t</a> </td><td class="memItemRight" valign="bottom"><a class="el" href="group__dns.html#gae84449f60dca6b863142daca8e03ce79">dns_gethostbyname_addrtype</a> (const char *hostname, <a class="el" href="group__ipaddr.html#ga16ef96d6cde029029bbf47fee35fd67a">ip_addr_t</a> *addr, <a class="el" href="dns_8h.html#ab5a9dec5b22802f91876c53e99f427ae">dns_found_callback</a> found, void *callback_arg, u8_t dns_addrtype)</td></tr> |
| <tr class="separator:gae84449f60dca6b863142daca8e03ce79"><td class="memSeparator" colspan="2"> </td></tr> |
| </table> |
| <a name="details" id="details"></a><h2 class="groupheader">Detailed Description</h2> |
| <p>Implements a DNS host name to IP address resolver.</p> |
| <p>The lwIP DNS resolver functions are used to lookup a host name and map it to a numerical IP address. It maintains a list of resolved hostnames that can be queried with the dns_lookup() function. New hostnames can be resolved using the <a class="el" href="structdns__query.html">dns_query()</a> function.</p> |
| <p>The lwIP version of the resolver also adds a non-blocking version of <a class="el" href="group__netdbapi.html#ga39746b4b096060ca3e8c6ee7a7560b1d">gethostbyname()</a> that will work with a raw API application. This function checks for an IP address string first and converts it if it is valid. <a class="el" href="group__netdbapi.html#ga39746b4b096060ca3e8c6ee7a7560b1d">gethostbyname()</a> then does a dns_lookup() to see if the name is already in the table. If so, the IP is returned. If not, a query is issued and the function returns with a ERR_INPROGRESS status. The app using the dns client must then go into a waiting state.</p> |
| <p>Once a hostname has been resolved (or found to be non-existent), the resolver code calls a specified callback function (which must be implemented by the module that uses the resolver).</p> |
| <p>Multicast DNS queries are supported for names ending on ".local". However, only "One-Shot Multicast DNS Queries" are supported (RFC 6762 chapter 5.1), this is not a fully compliant implementation of continuous mDNS querying!</p> |
| <p>All functions must be called from TCPIP thread.</p> |
| <dl class="section see"><dt>See also</dt><dd><a class="el" href="group__lwip__opts__dns.html#ga9f9881c887a8aceb9765820c2dbdf292">DNS_MAX_SERVERS</a> </dd> |
| <dd> |
| <a class="el" href="group__lwip__opts__dhcp.html#ga60ccc20fbb08be24b5d5f599dd47a6a6">LWIP_DHCP_MAX_DNS_SERVERS</a> </dd> |
| <dd> |
| <a class="el" href="group__netconn__common.html">Common functions</a> for thread-safe access. </dd></dl> |
| <h2 class="groupheader">Function Documentation</h2> |
| <a id="ga1e040ec38166dc9bfcc3473aab0c799f"></a> |
| <h2 class="memtitle"><span class="permalink"><a href="#ga1e040ec38166dc9bfcc3473aab0c799f">◆ </a></span>dns_gethostbyname()</h2> |
| |
| <div class="memitem"> |
| <div class="memproto"> |
| <table class="memname"> |
| <tr> |
| <td class="memname"><a class="el" href="group__infrastructure__errors.html#gaf02d9da80fd66b4f986d2c53d7231ddb">err_t</a> dns_gethostbyname </td> |
| <td>(</td> |
| <td class="paramtype">const char * </td> |
| <td class="paramname"><em>hostname</em>, </td> |
| </tr> |
| <tr> |
| <td class="paramkey"></td> |
| <td></td> |
| <td class="paramtype"><a class="el" href="group__ipaddr.html#ga16ef96d6cde029029bbf47fee35fd67a">ip_addr_t</a> * </td> |
| <td class="paramname"><em>addr</em>, </td> |
| </tr> |
| <tr> |
| <td class="paramkey"></td> |
| <td></td> |
| <td class="paramtype"><a class="el" href="dns_8h.html#ab5a9dec5b22802f91876c53e99f427ae">dns_found_callback</a> </td> |
| <td class="paramname"><em>found</em>, </td> |
| </tr> |
| <tr> |
| <td class="paramkey"></td> |
| <td></td> |
| <td class="paramtype">void * </td> |
| <td class="paramname"><em>callback_arg</em> </td> |
| </tr> |
| <tr> |
| <td></td> |
| <td>)</td> |
| <td></td><td></td> |
| </tr> |
| </table> |
| </div><div class="memdoc"> |
| <p>Resolve a hostname (string) into an IP address. NON-BLOCKING callback version for use with raw API!!!</p> |
| <p>Returns immediately with one of err_t return codes:</p><ul> |
| <li>ERR_OK if hostname is a valid IP address string or the host name is already in the local names table.</li> |
| <li>ERR_INPROGRESS enqueue a request to be sent to the DNS server for resolution if no errors are present.</li> |
| <li>ERR_ARG: dns client not initialized or invalid hostname</li> |
| </ul> |
| <dl class="params"><dt>Parameters</dt><dd> |
| <table class="params"> |
| <tr><td class="paramname">hostname</td><td>the hostname that is to be queried </td></tr> |
| <tr><td class="paramname">addr</td><td>pointer to a ip_addr_t where to store the address if it is already cached in the dns_table (only valid if ERR_OK is returned!) </td></tr> |
| <tr><td class="paramname">found</td><td>a callback function to be called on success, failure or timeout (only if ERR_INPROGRESS is returned!) </td></tr> |
| <tr><td class="paramname">callback_arg</td><td>argument to pass to the callback function </td></tr> |
| </table> |
| </dd> |
| </dl> |
| <dl class="section return"><dt>Returns</dt><dd>a err_t return code. </dd></dl> |
| |
| </div> |
| </div> |
| <a id="gae84449f60dca6b863142daca8e03ce79"></a> |
| <h2 class="memtitle"><span class="permalink"><a href="#gae84449f60dca6b863142daca8e03ce79">◆ </a></span>dns_gethostbyname_addrtype()</h2> |
| |
| <div class="memitem"> |
| <div class="memproto"> |
| <table class="memname"> |
| <tr> |
| <td class="memname"><a class="el" href="group__infrastructure__errors.html#gaf02d9da80fd66b4f986d2c53d7231ddb">err_t</a> dns_gethostbyname_addrtype </td> |
| <td>(</td> |
| <td class="paramtype">const char * </td> |
| <td class="paramname"><em>hostname</em>, </td> |
| </tr> |
| <tr> |
| <td class="paramkey"></td> |
| <td></td> |
| <td class="paramtype"><a class="el" href="group__ipaddr.html#ga16ef96d6cde029029bbf47fee35fd67a">ip_addr_t</a> * </td> |
| <td class="paramname"><em>addr</em>, </td> |
| </tr> |
| <tr> |
| <td class="paramkey"></td> |
| <td></td> |
| <td class="paramtype"><a class="el" href="dns_8h.html#ab5a9dec5b22802f91876c53e99f427ae">dns_found_callback</a> </td> |
| <td class="paramname"><em>found</em>, </td> |
| </tr> |
| <tr> |
| <td class="paramkey"></td> |
| <td></td> |
| <td class="paramtype">void * </td> |
| <td class="paramname"><em>callback_arg</em>, </td> |
| </tr> |
| <tr> |
| <td class="paramkey"></td> |
| <td></td> |
| <td class="paramtype">u8_t </td> |
| <td class="paramname"><em>dns_addrtype</em> </td> |
| </tr> |
| <tr> |
| <td></td> |
| <td>)</td> |
| <td></td><td></td> |
| </tr> |
| </table> |
| </div><div class="memdoc"> |
| <p>Like dns_gethostbyname, but returned address type can be controlled: </p><dl class="params"><dt>Parameters</dt><dd> |
| <table class="params"> |
| <tr><td class="paramname">hostname</td><td>the hostname that is to be queried </td></tr> |
| <tr><td class="paramname">addr</td><td>pointer to a ip_addr_t where to store the address if it is already cached in the dns_table (only valid if ERR_OK is returned!) </td></tr> |
| <tr><td class="paramname">found</td><td>a callback function to be called on success, failure or timeout (only if ERR_INPROGRESS is returned!) </td></tr> |
| <tr><td class="paramname">callback_arg</td><td>argument to pass to the callback function </td></tr> |
| <tr><td class="paramname">dns_addrtype</td><td>- LWIP_DNS_ADDRTYPE_IPV4_IPV6: try to resolve IPv4 first, try IPv6 if IPv4 fails only<ul> |
| <li>LWIP_DNS_ADDRTYPE_IPV6_IPV4: try to resolve IPv6 first, try IPv4 if IPv6 fails only</li> |
| <li>LWIP_DNS_ADDRTYPE_IPV4: try to resolve IPv4 only</li> |
| <li>LWIP_DNS_ADDRTYPE_IPV6: try to resolve IPv6 only </li> |
| </ul> |
| </td></tr> |
| </table> |
| </dd> |
| </dl> |
| |
| </div> |
| </div> |
| <a id="gad02111a6b26b93f1c3580d5f41a59af3"></a> |
| <h2 class="memtitle"><span class="permalink"><a href="#gad02111a6b26b93f1c3580d5f41a59af3">◆ </a></span>dns_getserver()</h2> |
| |
| <div class="memitem"> |
| <div class="memproto"> |
| <table class="memname"> |
| <tr> |
| <td class="memname">const <a class="el" href="group__ipaddr.html#ga16ef96d6cde029029bbf47fee35fd67a">ip_addr_t</a>* dns_getserver </td> |
| <td>(</td> |
| <td class="paramtype">u8_t </td> |
| <td class="paramname"><em>numdns</em></td><td>)</td> |
| <td></td> |
| </tr> |
| </table> |
| </div><div class="memdoc"> |
| <p>Obtain one of the currently configured DNS server.</p> |
| <dl class="params"><dt>Parameters</dt><dd> |
| <table class="params"> |
| <tr><td class="paramname">numdns</td><td>the index of the DNS server </td></tr> |
| </table> |
| </dd> |
| </dl> |
| <dl class="section return"><dt>Returns</dt><dd>IP address of the indexed DNS server or "ip_addr_any" if the DNS server has not been configured. </dd></dl> |
| |
| </div> |
| </div> |
| <a id="gaf66c5d8273f83cdc2cdd8911fb68d584"></a> |
| <h2 class="memtitle"><span class="permalink"><a href="#gaf66c5d8273f83cdc2cdd8911fb68d584">◆ </a></span>dns_setserver()</h2> |
| |
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| <div class="memproto"> |
| <table class="memname"> |
| <tr> |
| <td class="memname">void dns_setserver </td> |
| <td>(</td> |
| <td class="paramtype">u8_t </td> |
| <td class="paramname"><em>numdns</em>, </td> |
| </tr> |
| <tr> |
| <td class="paramkey"></td> |
| <td></td> |
| <td class="paramtype">const <a class="el" href="group__ipaddr.html#ga16ef96d6cde029029bbf47fee35fd67a">ip_addr_t</a> * </td> |
| <td class="paramname"><em>dnsserver</em> </td> |
| </tr> |
| <tr> |
| <td></td> |
| <td>)</td> |
| <td></td><td></td> |
| </tr> |
| </table> |
| </div><div class="memdoc"> |
| <p>Initialize one of the DNS servers.</p> |
| <dl class="params"><dt>Parameters</dt><dd> |
| <table class="params"> |
| <tr><td class="paramname">numdns</td><td>the index of the DNS server to set must be < DNS_MAX_SERVERS </td></tr> |
| <tr><td class="paramname">dnsserver</td><td>IP address of the DNS server to set </td></tr> |
| </table> |
| </dd> |
| </dl> |
| |
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