TEST_F(DNSTest, Answers) {
DNS dns;
dns.add_answer(
DNS::Resource("www.example.com", "127.0.0.1", DNS::A, DNS::IN, 0x762)
);
dns.add_answer(
DNS::Resource("www.example2.com", "mail.example.com", DNS::MX, DNS::IN, 0x762)
);
ASSERT_EQ(dns.answers_count(), 2);
DNS::resources_type resources = dns.answers();
for(DNS::resources_type::const_iterator it = resources.begin(); it != resources.end(); ++it) {
EXPECT_TRUE(it->dname() == "www.example.com" || it->dname() == "www.example2.com");
if(it->dname() == "www.example.com") {
EXPECT_EQ(it->type(), DNS::A);
EXPECT_EQ(it->ttl(), 0x762U);
EXPECT_EQ(it->data(), "127.0.0.1");
EXPECT_EQ(it->query_class(), DNS::IN);
}
else if(it->dname() == "www.example2.com") {
EXPECT_EQ(it->type(), DNS::MX);
EXPECT_EQ(it->ttl(), 0x762U);
EXPECT_EQ(it->data(), "mail.example.com");
EXPECT_EQ(it->query_class(), DNS::IN);
}
}
}
TEST_F(DNSTest, AnswersV6) {
DNS dns;
dns.add_answer(
DNS::Resource("www.example.com", "f9a8:239::1:1", DNS::AAAA, DNS::IN, 0x762)
);
dns.add_answer(
DNS::Resource("www.example.com", "f9a8:239::1:1", DNS::AAAA, DNS::IN, 0x762)
);
ASSERT_EQ(dns.answers_count(), 2);
DNS::resources_type resources = dns.answers();
for(DNS::resources_type::const_iterator it = resources.begin(); it != resources.end(); ++it) {
EXPECT_EQ(it->dname(), "www.example.com");
EXPECT_EQ(it->type(), DNS::AAAA);
EXPECT_EQ(it->ttl(), 0x762U);
EXPECT_EQ(it->data(), "f9a8:239::1:1");
EXPECT_EQ(it->query_class(), DNS::IN);
}
}
TEST_F(DNSTest, AnswersWithSameName) {
DNS dns;
dns.add_answer("www.example.com", DNS::make_info(DNS::A, DNS::IN, 0x762), IPv4Address("127.0.0.1"));
dns.add_answer("www.example.com", DNS::make_info(DNS::A, DNS::IN, 0x762), IPv4Address("127.0.0.2"));
ASSERT_EQ(dns.answers_count(), 2);
DNS::resources_type resources = dns.answers();
for(DNS::resources_type::const_iterator it = resources.begin(); it != resources.end(); ++it) {
EXPECT_TRUE(it->data() == "127.0.0.1" || it->data() == "127.0.0.2");
EXPECT_EQ(it->dname(), "www.example.com");
EXPECT_EQ(it->type(), DNS::A);
EXPECT_EQ(it->ttl(), 0x762U);
EXPECT_EQ(it->query_class(), DNS::IN);
}
}
bool callback(const PDU &pdu)
{
// The packet probably looks like this:
//
// EthernetII / IP / UDP / RawPDU
//
// So we retrieve each layer, and construct a
// DNS PDU from the RawPDU layer contents.
EthernetII eth = pdu.rfind_pdu<EthernetII>();
IP ip = eth.rfind_pdu<IP>();
UDP udp = ip.rfind_pdu<UDP>();
DNS dns = udp.rfind_pdu<RawPDU>().to<DNS>();
// Is it a DNS query?
if(dns.type() == DNS::QUERY) {
// Let's see if there's any query for an "A" record.
for(const auto &query : dns.queries()) {
if(query.type() == DNS::A) {
// Here's one! Let's add an answer.
dns.add_answer(
DNS::Resource(
query.dname(),
"127.0.0.1",
DNS::A,
query.query_class(),
// 777 is just a random TTL
777
)
);
}
}
// Have we added some answers?
if(dns.answers_count() > 0) {
// It's a response now
dns.type(DNS::RESPONSE);
// Recursion is available(just in case)
dns.recursion_available(1);
// Build our packet
auto pkt = EthernetII(eth.src_addr(), eth.dst_addr()) /
IP(ip.src_addr(), ip.dst_addr()) /
UDP(udp.sport(), udp.dport()) /
dns;
// Send it!
sender.send(pkt);
}
}
return true;
}