Added function to check syntax of URL for DNS lookup

For now, simply checks for '.' character, but that will be easy to
change in the future if necessary/desired.
This commit is contained in:
Thomas Winget 2014-09-18 09:07:46 -04:00 committed by Riccardo Spagni
parent 24f325a33d
commit 1dece111cc
2 changed files with 44 additions and 8 deletions

View File

@ -79,11 +79,16 @@ DNSResolver::~DNSResolver()
std::vector<std::string> DNSResolver::get_ipv4(const std::string& url) std::vector<std::string> DNSResolver::get_ipv4(const std::string& url)
{ {
std::vector<std::string> addresses;
if (!check_address_syntax(url))
{
return addresses;
}
// destructor takes care of cleanup // destructor takes care of cleanup
ub_result_ptr result; ub_result_ptr result;
std::vector<std::string> retval;
// call DNS resolver, blocking. if return value not zero, something went wrong // call DNS resolver, blocking. if return value not zero, something went wrong
if (!ub_resolve(m_data->m_ub_context, url.c_str(), LDNS_RR_TYPE_A, LDNS_RR_CLASS_IN, &(result.ptr))) if (!ub_resolve(m_data->m_ub_context, url.c_str(), LDNS_RR_TYPE_A, LDNS_RR_CLASS_IN, &(result.ptr)))
{ {
@ -96,19 +101,25 @@ std::vector<std::string> DNSResolver::get_ipv4(const std::string& url)
// convert bytes to string, append if no error // convert bytes to string, append if no error
if (inet_ntop(AF_INET, result.ptr->data[i], as_str, sizeof(as_str))) if (inet_ntop(AF_INET, result.ptr->data[i], as_str, sizeof(as_str)))
{ {
retval.push_back(as_str); addresses.push_back(as_str);
} }
} }
} }
} }
return retval; return addresses;
} }
std::vector<std::string> DNSResolver::get_ipv6(const std::string& url) std::vector<std::string> DNSResolver::get_ipv6(const std::string& url)
{ {
std::vector<std::string> addresses;
if (!check_address_syntax(url))
{
return addresses;
}
ub_result_ptr result; ub_result_ptr result;
std::vector<std::string> retval;
// call DNS resolver, blocking. if return value not zero, something went wrong // call DNS resolver, blocking. if return value not zero, something went wrong
if (!ub_resolve(m_data->m_ub_context, url.c_str(), LDNS_RR_TYPE_AAAA, LDNS_RR_CLASS_IN, &(result.ptr))) if (!ub_resolve(m_data->m_ub_context, url.c_str(), LDNS_RR_TYPE_AAAA, LDNS_RR_CLASS_IN, &(result.ptr)))
@ -122,20 +133,26 @@ std::vector<std::string> DNSResolver::get_ipv6(const std::string& url)
// convert bytes to string, append if no error // convert bytes to string, append if no error
if (inet_ntop(AF_INET6, result.ptr->data[i], as_str, sizeof(as_str))) if (inet_ntop(AF_INET6, result.ptr->data[i], as_str, sizeof(as_str)))
{ {
retval.push_back(as_str); addresses.push_back(as_str);
} }
} }
} }
} }
return retval; return addresses;
} }
std::vector<std::string> DNSResolver::get_txt_record(const std::string& url) std::vector<std::string> DNSResolver::get_txt_record(const std::string& url)
{ {
ub_result_ptr result;
std::vector<std::string> records; std::vector<std::string> records;
if (!check_address_syntax(url))
{
return records;
}
ub_result_ptr result;
// call DNS resolver, blocking. if return value not zero, something went wrong // call DNS resolver, blocking. if return value not zero, something went wrong
if (!ub_resolve(m_data->m_ub_context, url.c_str(), LDNS_RR_TYPE_TXT, LDNS_RR_CLASS_IN, &(result.ptr))) if (!ub_resolve(m_data->m_ub_context, url.c_str(), LDNS_RR_TYPE_TXT, LDNS_RR_CLASS_IN, &(result.ptr)))
{ {
@ -161,4 +178,14 @@ DNSResolver& DNSResolver::instance()
return *staticInstance; return *staticInstance;
} }
bool DNSResolver::check_address_syntax(const std::string& addr)
{
// if string doesn't contain a dot, we won't consider it a url for now.
if (addr.find(".") == std::string::npos)
{
return false;
}
return true;
}
} // namespace tools } // namespace tools

View File

@ -101,6 +101,15 @@ public:
private: private:
/**
* @brief Checks a string to see if it looks like a URL
*
* @param addr the string to be checked
*
* @return true if it looks enough like a URL, false if not
*/
bool check_address_syntax(const std::string& addr);
DNSResolverData *m_data; DNSResolverData *m_data;
}; // class DNSResolver }; // class DNSResolver