lwipNetDnsRequest.cpp

00001 
00002 /*
00003 Copyright (c) 2010 Donatien Garnier (donatiengar [at] gmail [dot] com)
00004  
00005 Permission is hereby granted, free of charge, to any person obtaining a copy
00006 of this software and associated documentation files (the "Software"), to deal
00007 in the Software without restriction, including without limitation the rights
00008 to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
00009 copies of the Software, and to permit persons to whom the Software is
00010 furnished to do so, subject to the following conditions:
00011  
00012 The above copyright notice and this permission notice shall be included in
00013 all copies or substantial portions of the Software.
00014  
00015 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
00016 IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
00017 FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
00018 AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
00019 LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
00020 OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
00021 THE SOFTWARE.
00022 */
00023 
00024 #include "lwipNetDnsRequest.h"
00025 #include "lwip/err.h" //err_t, ERR_xxx
00026 #include "lwip/dns.h"
00027 
00028 #include "netCfg.h"
00029 #if NET_LWIP_STACK
00030 
00031 //#define __DEBUG
00032 #include "dbg/dbg.h"
00033 
00034 LwipNetDnsRequest::LwipNetDnsRequest(const char* hostname) : NetDnsRequest(hostname), m_state(LWIPNETDNS_START), m_cbFired(false), m_closing(false)
00035 {
00036   DBG("New LwipNetDnsRequest %p\n", this);
00037 }
00038 
00039 LwipNetDnsRequest::LwipNetDnsRequest(Host* pHost) : NetDnsRequest(pHost), m_state(LWIPNETDNS_START), m_cbFired(false), m_closing(false)
00040 {
00041   DBG("New LwipNetDnsRequest %p\n", this);
00042 }
00043 
00044 LwipNetDnsRequest::~LwipNetDnsRequest()
00045 {
00046   DBG("LwipNetDnsRequest %p destroyed\n", this);
00047 }
00048 
00049 /*
00050 Main useful function here (see lwip/dns.h):
00051 err_t          dns_gethostbyname(const char *hostname, ip_addr_t *addr,
00052                                  dns_found_callback found, void *callback_arg);
00053 */
00054 
00055 //Execute request & return OK if found, NOTFOUND or ERROR on error, or PROCESSING if the request has not completed yet
00056 void LwipNetDnsRequest::poll()
00057 {
00058   err_t  err;
00059   switch(m_state)
00060   {
00061   case LWIPNETDNS_START: //First req, let's call dns_gethostbyname
00062     ip_addr_t ipStruct;
00063     err = dns_gethostbyname(m_hostname, &ipStruct, LwipNetDnsRequest::sFoundCb, (void*) this );
00064     if( err == ERR_OK )
00065     {
00066       m_ip = IpAddr(&ipStruct);
00067       m_state = LWIPNETDNS_OK;
00068       DBG("DNS: Ip found in cache.\n");
00069     }
00070     else if( err == ERR_INPROGRESS)
00071     {
00072       DBG("DNS: Processing.\n");
00073       m_state = LWIPNETDNS_PROCESSING;
00074     }
00075     else //Likely ERR_VAL
00076     {
00077       DBG("DNS: Error on init.\n");
00078       m_state = LWIPNETDNS_ERROR;
00079     }
00080     break;
00081   case LWIPNETDNS_PROCESSING:
00082     break; //Nothing to do, DNS is polled on interrupt
00083   case LWIPNETDNS_OK:
00084     if(!m_cbFired)
00085     {
00086       DBG("DNS: Ip found.\n");
00087       m_cbFired = true;
00088       onReply(NETDNS_FOUND); //Raise callback
00089     }
00090     break;
00091   case LWIPNETDNS_NOTFOUND:
00092     if(!m_cbFired)
00093     {
00094       DBG("DNS: could not be resolved.\n");
00095       m_cbFired = true;
00096       onReply(NETDNS_NOTFOUND); //Raise callback
00097     }  
00098     break;  
00099   case LWIPNETDNS_ERROR:
00100   default:
00101     if(!m_cbFired)
00102     {
00103       DBG("DNS: Error.\n");
00104       m_cbFired = true;
00105       onReply(NETDNS_ERROR); //Raise callback
00106     }  
00107     break; 
00108   }
00109   if(m_closing && (m_state!=LWIPNETDNS_PROCESSING)) //Check wether the closure has been reqd
00110   {
00111     DBG("LwipNetDnsRequest: Closing in poll()\n");
00112     NetDnsRequest::close();
00113   }
00114 }
00115 
00116 void LwipNetDnsRequest::close()
00117 {
00118   DBG("LwipNetDnsRequest: Close req\n");
00119   if(m_state!=LWIPNETDNS_PROCESSING)
00120   {
00121     DBG("LwipNetDnsRequest: Closing in close()\n");
00122     NetDnsRequest::close();
00123   }
00124   else //Cannot close rightaway, waiting for callback from underlying layer
00125   {
00126     m_closing = true;
00127   }
00128 }
00129 
00130 void LwipNetDnsRequest::foundCb(const char *name, ip_addr_t *ipaddr)
00131 {
00132   if( ipaddr == NULL )
00133   {
00134     DBG("LwipNetDnsRequest: Callback: Name not found\n");
00135     m_state = LWIPNETDNS_NOTFOUND;
00136     return;
00137   }
00138   DBG("LwipNetDnsRequest: Callback: Resolved\n");
00139   m_ip = IpAddr(ipaddr);
00140   m_state = LWIPNETDNS_OK;
00141 }
00142 
00143 
00144 void LwipNetDnsRequest::sFoundCb(const char *name, ip_addr_t *ipaddr, void *arg)
00145 {
00146   DBG("LwipNetDnsRequest: Static callback\n");
00147   LwipNetDnsRequest* pMe = (LwipNetDnsRequest*) arg;
00148   return pMe->foundCb( name, ipaddr );
00149 }
00150 
00151 #endif
00152