bool TcpSocket::ConnectToHost(const string& hostName,
const string& port,
IBamIODevice::OpenMode mode)
{
// create new address object with requested host name
HostAddress hostAddress;
hostAddress.SetAddress(hostName);
HostInfo info;
// if host name was IP address ("x.x.x.x" or IPv6 format)
// otherwise host name was 'plain-text' ("www.foo.bar")
// we need to look up IP address(es)
if ( hostAddress.HasIPAddress() )
info.SetAddresses( vector<HostAddress>(1, hostAddress) );
else
info = HostInfo::Lookup(hostName, port);
// attempt connection on requested port
return ConnectImpl(info, port, mode);
}
HostInfo HostInfo::Lookup(const string& hostname, const string& port) {
HostInfo result;
result.SetHostName(hostname);
set<HostAddress> uniqueAddresses;
#ifdef _WIN32
WindowsSockInit init;
#endif
HostAddress address;
address.SetAddress(hostname);
// if hostname is an IP string ('0.0.0.0' or IPv6 format)
// do reverse lookup for host domain name
//
// TODO: might just remove this... not sure if proper 'hostname' from IP string is needed
//
// so far, haven't been able to successfully fetch a domain name with reverse DNS
// getnameinfo() on test sites just returns original IP string. BUT this is likely a rare
// case that client code tries to use an IP string and the connection should work fine
// anyway. GetHostName() just won't quite show what I was hoping for. :(
if ( address.HasIPAddress() ) {
const uint16_t portNum = static_cast<uint16_t>( atoi(port.c_str()) );
sockaddr_in sa4;
sockaddr_in6 sa6;
sockaddr* sa = 0;
BT_SOCKLEN_T saSize = 0;
// IPv4
if ( address.GetProtocol() == HostAddress::IPv4Protocol ) {
sa = (sockaddr*)&sa4;
saSize = sizeof(sa4);
memset(&sa4, 0, sizeof(sa4));
sa4.sin_family = AF_INET;
sa4.sin_addr.s_addr = htonl(address.GetIPv4Address());
sa4.sin_port = htons(portNum);
}
// IPv6
else if ( address.GetProtocol() == HostAddress::IPv4Protocol ){
sa = (sockaddr*)&sa6;
saSize = sizeof(sa6);
memset(&sa6, 0, sizeof(sa6));
sa6.sin6_family = AF_INET6;
memcpy(sa6.sin6_addr.s6_addr, address.GetIPv6Address().data, sizeof(sa6.sin6_addr.s6_addr));
sa6.sin6_port = htons(portNum);
}
// unknown (should be unreachable)
else BT_ASSERT_X(false, "HostInfo::Lookup: unknown network protocol");
// lookup name for IP
char hbuf[NI_MAXHOST];
char serv[NI_MAXSERV];
if ( sa && (getnameinfo(sa, saSize, hbuf, sizeof(hbuf), serv, sizeof(serv), 0) == 0) )
result.SetHostName(string(hbuf));
// if no domain name found, just use the original address's IP string
if ( result.HostName().empty() )
result.SetHostName(address.GetIPString());
// store address in HostInfo
uniqueAddresses.insert(address);
}
// otherwise, hostname is a domain name ('www.foo.bar')
// do 'normal' lookup
else {
// setup address lookup 'hints'
addrinfo hints;
memset(&hints, 0, sizeof(hints));
hints.ai_family = AF_UNSPEC; // allow either IPv4 or IPv6
hints.ai_socktype = SOCK_STREAM; // for TCP
hints.ai_protocol = IPPROTO_TCP;
// fetch addresses for requested hostname/port
addrinfo* res;
int status = getaddrinfo(hostname.c_str(), port.c_str(), &hints, &res );
// if everything OK
if ( status == 0 ) {
// iterate over all IP addresses found
addrinfo* p = res;
for ( ; p != NULL; p = p->ai_next ) {
// IPv4
if ( p->ai_family == AF_INET ) {
sockaddr_in* ipv4 = (sockaddr_in*)p->ai_addr;
HostAddress a( ntohl(ipv4->sin_addr.s_addr) );
uniqueAddresses.insert(a);
}
// IPv6
else if ( p->ai_family == AF_INET6 ) {
sockaddr_in6* ipv6 = (sockaddr_in6*)p->ai_addr;
HostAddress a(ipv6->sin6_addr.s6_addr);
uniqueAddresses.insert(a);
}
}
// if we iterated, but no addresses were stored
if ( uniqueAddresses.empty() && (p == NULL) ) {
result.SetError(HostInfo::UnknownError);
result.SetErrorString("HostInfo: unknown address types found");
}
}
// handle error cases
else if (
#ifndef _WIN32
status == EAI_NONAME
|| status == EAI_FAIL
# ifdef EAI_NODATA
|| status == EAI_NODATA // officially deprecated, but just in case we happen to hit it
# endif // EAI_NODATA
#else // _WIN32
WSAGetLastError() == WSAHOST_NOT_FOUND
|| WSAGetLastError() == WSANO_DATA
|| WSAGetLastError() == WSANO_RECOVERY
#endif // _WIN32
)
{
result.SetError(HostInfo::HostNotFound);
result.SetErrorString("HostInfo: host not found");
}
else {
result.SetError(HostInfo::UnknownError);
result.SetErrorString("HostInfo: unknown error encountered");
}
// cleanup
freeaddrinfo(res);
}
// store fetched addresses (converting set -> vector) in result & return
result.SetAddresses( vector<HostAddress>(uniqueAddresses.begin(), uniqueAddresses.end()) );
return result;
}
