New DNS implementation.

src/base/net/dns/DnsUvBackend.cpp

@@ -0,0 +1,130 @@
+/* XMRig
+ * Copyright (c) 2018-2021 SChernykh   <https://github.com/SChernykh>
+ * Copyright (c) 2016-2021 XMRig       <https://github.com/xmrig>, <support@xmrig.com>
+ *
+ *   This program is free software: you can redistribute it and/or modify
+ *   it under the terms of the GNU General Public License as published by
+ *   the Free Software Foundation, either version 3 of the License, or
+ *   (at your option) any later version.
+ *
+ *   This program is distributed in the hope that it will be useful,
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ *   GNU General Public License for more details.
+ *
+ *   You should have received a copy of the GNU General Public License
+ *   along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+
+#include <uv.h>
+
+
+#include "base/net/dns/DnsUvBackend.h"
+#include "base/kernel/interfaces/IDnsListener.h"
+#include "base/net/dns/DnsRequest.h"
+#include "base/tools/Chrono.h"
+
+
+namespace xmrig {
+
+
+Storage<DnsUvBackend> DnsUvBackend::m_storage;
+
+static addrinfo hints{};
+
+
+} // namespace xmrig
+
+
+xmrig::DnsUvBackend::DnsUvBackend()
+{
+    if (!hints.ai_protocol) {
+        hints.ai_family     = AF_UNSPEC;
+        hints.ai_socktype   = SOCK_STREAM;
+        hints.ai_protocol   = IPPROTO_TCP;
+    }
+
+    m_key = m_storage.add(this);
+}
+
+
+xmrig::DnsUvBackend::~DnsUvBackend()
+{
+    m_storage.release(m_key);
+}
+
+
+std::shared_ptr<xmrig::DnsRequest> xmrig::DnsUvBackend::resolve(const String &host, IDnsListener *listener, uint64_t ttl)
+{
+    auto req = std::make_shared<DnsRequest>(listener);
+
+    if (Chrono::currentMSecsSinceEpoch() - m_ts <= ttl && !m_records.isEmpty()) {
+        req->listener->onResolved(m_records, 0, nullptr);
+    } else {
+        m_queue.emplace(req);
+    }
+
+    if (m_queue.size() == 1 && !resolve(host)) {
+        done();
+    }
+
+    return req;
+}
+
+
+bool xmrig::DnsUvBackend::resolve(const String &host)
+{
+    m_req = std::make_shared<uv_getaddrinfo_t>();
+    m_req->data = m_storage.ptr(m_key);
+
+    m_status = uv_getaddrinfo(uv_default_loop(), m_req.get(), DnsUvBackend::onResolved, host.data(), nullptr, &hints);
+
+    return m_status == 0;
+}
+
+
+void xmrig::DnsUvBackend::done()
+{
+    const char *error = m_status < 0 ? uv_strerror(m_status) : nullptr;
+
+    while (!m_queue.empty()) {
+        auto req = std::move(m_queue.front()).lock();
+        if (req) {
+            req->listener->onResolved(m_records, m_status, error);
+        }
+
+        m_queue.pop();
+    }
+
+    m_req.reset();
+}
+
+
+void xmrig::DnsUvBackend::onResolved(int status, addrinfo *res)
+{
+    m_ts = Chrono::currentMSecsSinceEpoch();
+
+    if ((m_status = status) < 0) {
+        return done();
+    }
+
+    m_records.parse(res);
+
+    if (m_records.isEmpty()) {
+        m_status = UV_EAI_NONAME;
+    }
+
+    done();
+}
+
+
+void xmrig::DnsUvBackend::onResolved(uv_getaddrinfo_t *req, int status, addrinfo *res)
+{
+    auto backend = m_storage.get(req->data);
+    if (backend) {
+        backend->onResolved(status, res);
+    }
+
+    uv_freeaddrinfo(res);
+}