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dns_utils: factor the fetching code for different DNS record types

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moneromooo-monero 2015-08-29 12:53:01 +01:00
parent 4ef0da184d
commit f928468b9b
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GPG key ID: 686F07454D6CEFC3
2 changed files with 34 additions and 59 deletions
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80
src/common/dns_utils.cpp
View file

@ -100,8 +100,10 @@ namespace tools
{
// fuck it, I'm tired of dealing with getnameinfo()/inet_ntop/etc
std::string ipv4_to_string(const char* src)
std::string ipv4_to_string(const char* src, size_t len)
{
assert(memchr(src, 0, len));
std::stringstream ss;
unsigned int bytes[4];
for (int i = 0; i < 4; i++)
@ -118,8 +120,10 @@ std::string ipv4_to_string(const char* src)
// this obviously will need to change, but is here to reflect the above
// stop-gap measure and to make the tests pass at least...
std::string ipv6_to_string(const char* src)
std::string ipv6_to_string(const char* src, size_t len)
{
assert(memchr(src, 0, len));
std::stringstream ss;
unsigned int bytes[8];
for (int i = 0; i < 8; i++)
@ -138,6 +142,11 @@ std::string ipv6_to_string(const char* src)
return ss.str();
}
std::string txt_to_string(const char* src, size_t len)
{
return std::string(src+1, len-1);
}
// custom smart pointer.
// TODO: see if std::auto_ptr and the like support custom destructors
template<typename type, void (*freefunc)(type*)>
@ -215,7 +224,7 @@ DNSResolver::~DNSResolver()
}
}
std::vector<std::string> DNSResolver::get_ipv4(const std::string& url, bool& dnssec_available, bool& dnssec_valid)
std::vector<std::string> DNSResolver::get_record(const std::string& url, int record_type, std::string (*reader)(const char *,size_t), bool& dnssec_available, bool& dnssec_valid)
{
std::vector<std::string> addresses;
dnssec_available = false;
@ -231,7 +240,7 @@ std::vector<std::string> DNSResolver::get_ipv4(const std::string& url, bool& dns
ub_result_ptr result;
// call DNS resolver, blocking. if return value not zero, something went wrong
if (!ub_resolve(m_data->m_ub_context, urlC, DNS_TYPE_A, DNS_CLASS_IN, &result))
if (!ub_resolve(m_data->m_ub_context, urlC, record_type, DNS_CLASS_IN, &result))
{
dnssec_available = (result->secure || (!result->secure && result->bogus));
dnssec_valid = result->secure && !result->bogus;
@ -239,7 +248,7 @@ std::vector<std::string> DNSResolver::get_ipv4(const std::string& url, bool& dns
{
for (size_t i=0; result->data[i] != NULL; i++)
{
addresses.push_back(ipv4_to_string(result->data[i]));
addresses.push_back((*reader)(result->data[i], result->len[i]));
}
}
}
@ -247,66 +256,19 @@ std::vector<std::string> DNSResolver::get_ipv4(const std::string& url, bool& dns
return addresses;
}
std::vector<std::string> DNSResolver::get_ipv4(const std::string& url, bool& dnssec_available, bool& dnssec_valid)
{
return get_record(url, DNS_TYPE_A, ipv4_to_string, dnssec_available, dnssec_valid);
}
std::vector<std::string> DNSResolver::get_ipv6(const std::string& url, bool& dnssec_available, bool& dnssec_valid)
{
std::vector<std::string> addresses;
dnssec_available = false;
dnssec_valid = false;
string_ptr urlC(strdup(url.c_str()));
if (!check_address_syntax(urlC))
{
return addresses;
}
ub_result_ptr result;
// call DNS resolver, blocking. if return value not zero, something went wrong
if (!ub_resolve(m_data->m_ub_context, urlC, DNS_TYPE_AAAA, DNS_CLASS_IN, &result))
{
dnssec_available = (result->secure || (!result->secure && result->bogus));
dnssec_valid = result->secure && !result->bogus;
if (result->havedata)
{
for (size_t i=0; result->data[i] != NULL; i++)
{
addresses.push_back(ipv6_to_string(result->data[i]));
}
}
}
return addresses;
return get_record(url, DNS_TYPE_AAAA, ipv6_to_string, dnssec_available, dnssec_valid);
}
std::vector<std::string> DNSResolver::get_txt_record(const std::string& url, bool& dnssec_available, bool& dnssec_valid)
{
std::vector<std::string> records;
dnssec_available = false;
dnssec_valid = false;
string_ptr urlC(strdup(url.c_str()));
if (!check_address_syntax(urlC))
{
return records;
}
ub_result_ptr result;
// call DNS resolver, blocking. if return value not zero, something went wrong
if (!ub_resolve(m_data->m_ub_context, urlC, DNS_TYPE_TXT, DNS_CLASS_IN, &result))
{
dnssec_available = (result->secure || (!result->secure && result->bogus));
dnssec_valid = result->secure && !result->bogus;
if (result->havedata)
{
for (size_t i=0; result->data[i] != NULL; i++)
{
records.push_back(std::string(result->data[i]+1, result->len[i]-1));
}
}
}
return records;
return get_record(url, DNS_TYPE_TXT, txt_to_string, dnssec_available, dnssec_valid);
}
std::string DNSResolver::get_dns_format_from_oa_address(const std::string& oa_addr)

13
src/common/dns_utils.h
View file

@ -130,6 +130,19 @@ public:
private:
/**
* @brief gets all records of a given type from a DNS query for the supplied URL;
* if no such record is present returns an empty vector.
*
* @param url A string containing a URL to query for
* @param record_type the record type to retrieve (DNS_TYPE_A, etc)
* @param reader a function that converts a record data to a string
*
* @return A vector of strings containing the requested record; or an empty vector
*/
// TODO: modify this to accomodate DNSSEC
std::vector<std::string> get_record(const std::string& url, int record_type, std::string (*reader)(const char *,size_t), bool& dnssec_available, bool& dnssec_valid);
/**
* @brief Checks a string to see if it looks like a URL
*