lw-support/src/liblw-support/Net/Address/IPv4.cpp

/* lw-support/src/lib/Net/Address/IPv4.cpp
 *
 *  (c)2005, Laurence Withers. Released under the GNU GPL. See file
 *  COPYING for more information / terms of license.
*/

namespace lw {



const NetAddressIPv4 NetAddressIPv4::any(0, 0, 0, 0);
const NetAddressIPv4 NetAddressIPv4::loopback(127, 0, 0, 1);



std::wstring NetAddressIPv4::toString() const
{
    std::wostringstream o;

    o << (uint)(addr[0]) << L'.'
      << (uint)(addr[1]) << L'.'
      << (uint)(addr[2]) << L'.'
      << (uint)(addr[3]);

    return o.str();
}



NetAddressIPv4 NetAddressIPv4::fromString(const std::wstring& strIn)
{
    std::wstring str = stripWhitespace(strIn);

    uint8_t addr[4];
    int addrPos = 0;
    uint p = 0;
    bool seen = false;
    wchar_t ch;

    std::wstring::size_type pos = 0, len = str.length();

    for(pos = 0; pos < len; ++pos) {
        ch = str[pos];
        switch(ch) {
            case '0' ... '9':
                seen = true;
                p *= 10;
                p += (ch - '0');
                if(p > 255) {
                    throw ParseError(L"Octet cannot be > 255.", str, pos)
                        .chain(L"NetAddressIPv4::fromString()");
                }
                break;

            case '.':
                if(!seen) {
                    throw ParseError(L"Empty octet.", str, pos)
                        .chain(L"NetAddressIPv4::fromString()");
                }
                if(addrPos == 3) {
                    throw ParseError(L"Too many octets.", str, pos)
                        .chain(L"NetAddressIPv4::fromString()");
                }

                addr[addrPos++] = p;
                p = 0;
                seen = false;
                break;

            default:
                throw ParseError(L"Unexpected symbol.", str, pos)
                    .chain(L"NetAddressIPv4::fromString()");
        }
    }

    if(addrPos != 3 || !seen) {
        throw ParseError(L"Not enough octets.", str, pos)
            .chain(L"NetAddressIPv4::fromString()");
    }

    addr[3] = p;
    return NetAddressIPv4(addr);
}



NetAddressIPv4 NetAddressIPv4::fromDNS(const std::string& host)
{
    // attempt to convert from numeric form first
    try {
        return fromString(lw::asciiToUcs4(host));
    }
    catch(...) { }

    // now perform blocking DNS lookup
    struct hostent he, * hep = 0;
    int err = 0, result = 0;
    char buffer[4096];

    result = gethostbyname2_r(host.c_str(), AF_INET,
        &he, buffer, sizeof(buffer), &hep, &err);
    switch(result) {
        case 0:
            // success!
            break;

        case HOST_NOT_FOUND:
            throw DnsError(L"Host not found.", host);

        case TRY_AGAIN:
            throw DnsError(L"Temporary failure in name resolution.", host);

        case NO_RECOVERY:
            throw DnsError(L"Unrecoverable failure in name resolution.", host);

        case NO_ADDRESS:
            throw DnsError(L"Host does not have an associated IPv4 address.", host);

        default:
            throw DnsError(L"Unknown DNS error.", host);
    }


    return NetAddressIPv4(he.h_addr);
}



}