137 lines
3.4 KiB
C++
137 lines
3.4 KiB
C++
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// HostnameLookup.cpp
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// Implements the cHostnameLookup class representing an in-progress hostname-to-IP lookup
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#include "Globals.h"
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#include "HostnameLookup.h"
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#include <event2/dns.h>
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#include "NetworkSingleton.h"
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////////////////////////////////////////////////////////////////////////////////
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// cHostnameLookup:
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cHostnameLookup::cHostnameLookup(cNetwork::cResolveNameCallbacksPtr a_Callbacks):
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m_Callbacks(a_Callbacks)
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{
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}
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void cHostnameLookup::Lookup(const AString & a_Hostname)
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{
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// Store the hostname for the callback:
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m_Hostname = a_Hostname;
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// Start the lookup:
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// Note that we don't have to store the LibEvent lookup handle, LibEvent will free it on its own.
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evutil_addrinfo hints;
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memset(&hints, 0, sizeof(hints));
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hints.ai_protocol = IPPROTO_TCP;
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hints.ai_socktype = SOCK_STREAM;
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hints.ai_family = AF_UNSPEC;
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hints.ai_flags = EVUTIL_AI_CANONNAME;
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evdns_getaddrinfo(cNetworkSingleton::Get().GetDNSBase(), a_Hostname.c_str(), nullptr, &hints, Callback, this);
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}
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void cHostnameLookup::Callback(int a_ErrCode, evutil_addrinfo * a_Addr, void * a_Self)
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{
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// Get the Self class:
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cHostnameLookup * Self = reinterpret_cast<cHostnameLookup *>(a_Self);
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ASSERT(Self != nullptr);
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// If an error has occurred, notify the error callback:
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if (a_ErrCode != 0)
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{
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Self->m_Callbacks->OnError(a_ErrCode, evutil_socket_error_to_string(a_ErrCode));
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cNetworkSingleton::Get().RemoveHostnameLookup(Self);
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return;
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}
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// Call the success handler for each entry received:
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bool HasResolved = false;
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evutil_addrinfo * OrigAddr = a_Addr;
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for (;a_Addr != nullptr; a_Addr = a_Addr->ai_next)
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{
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char IP[128];
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switch (a_Addr->ai_family)
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{
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case AF_INET: // IPv4
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{
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sockaddr_in * sin = reinterpret_cast<sockaddr_in *>(a_Addr->ai_addr);
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if (!Self->m_Callbacks->OnNameResolvedV4(Self->m_Hostname, sin))
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{
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// Callback indicated that the IP shouldn't be serialized to a string, just continue with the next address:
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HasResolved = true;
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continue;
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}
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evutil_inet_ntop(AF_INET, &(sin->sin_addr), IP, sizeof(IP));
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break;
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}
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case AF_INET6: // IPv6
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{
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sockaddr_in6 * sin = reinterpret_cast<sockaddr_in6 *>(a_Addr->ai_addr);
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if (!Self->m_Callbacks->OnNameResolvedV6(Self->m_Hostname, sin))
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{
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// Callback indicated that the IP shouldn't be serialized to a string, just continue with the next address:
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HasResolved = true;
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continue;
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}
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evutil_inet_ntop(AF_INET6, &(sin->sin6_addr), IP, sizeof(IP));
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break;
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}
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default:
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{
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// Unknown address family, handle as if this entry wasn't received
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continue; // for (a_Addr)
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}
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}
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Self->m_Callbacks->OnNameResolved(Self->m_Hostname, IP);
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HasResolved = true;
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} // for (a_Addr)
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// If only unsupported families were reported, call the Error handler:
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if (!HasResolved)
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{
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Self->m_Callbacks->OnError(DNS_ERR_NODATA, "The name does not resolve to any known address.");
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}
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else
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{
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Self->m_Callbacks->OnFinished();
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}
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evutil_freeaddrinfo(OrigAddr);
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cNetworkSingleton::Get().RemoveHostnameLookup(Self);
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}
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////////////////////////////////////////////////////////////////////////////////
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// cNetwork API:
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bool cNetwork::HostnameToIP(
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const AString & a_Hostname,
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cNetwork::cResolveNameCallbacksPtr a_Callbacks
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)
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{
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auto Lookup = std::make_shared<cHostnameLookup>(a_Callbacks);
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cNetworkSingleton::Get().AddHostnameLookup(Lookup);
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Lookup->Lookup(a_Hostname);
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return true;
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}
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