1 files changed, 54 insertions, 0 deletions
diff --git a/trackersservicestandalone/src/main/java/foundation/e/advancedprivacy/trackers/service/usecases/ResolveDNSUseCase.kt b/trackersservicestandalone/src/main/java/foundation/e/advancedprivacy/trackers/service/usecases/ResolveDNSUseCase.kt
new file mode 100644
index 0000000..ac8aee0
--- /dev/null
+++ b/trackersservicestandalone/src/main/java/foundation/e/advancedprivacy/trackers/service/usecases/ResolveDNSUseCase.kt
@@ -0,0 +1,54 @@
+/*
+ * Copyright (C) 2023 MURENA SAS
+ *
+ * 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 <https://www.gnu.org/licenses/>.
+ */
+package foundation.e.advancedprivacy.trackers.service.usecases
+
+import foundation.e.advancedprivacy.trackers.domain.usecases.FilterHostnameUseCase
+import foundation.e.advancedprivacy.trackers.service.data.NetworkDNSAddressRepository
+import foundation.e.advancedprivacy.trackers.service.data.RequestDNSRepository
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.DelicateCoroutinesApi
+import kotlinx.coroutines.GlobalScope
+import org.pcap4j.packet.DnsPacket
+import org.pcap4j.packet.namednumber.DnsRCode
+import java.net.DatagramPacket
+
+@OptIn(DelicateCoroutinesApi::class)
+class ResolveDNSUseCase(
+    private val networkDNSAddressRepository: NetworkDNSAddressRepository,
+    private val filterHostnameUseCase: FilterHostnameUseCase,
+    private val requestDNSRepository: RequestDNSRepository,
+    private val scope: CoroutineScope = GlobalScope
+) {
+    private val DNS_PORT = 53
+
+    init {
+        filterHostnameUseCase.writeLogJob(scope)
+    }
+
+    suspend fun processDNS(dnsRequest: DnsPacket): DnsPacket? {
+        val host = dnsRequest.header.questions[0].qName.name
+        if (filterHostnameUseCase.shouldBlock(host)) {
+            return dnsRequest.builder
+                .rCode(DnsRCode.NX_DOMAIN)
+                .response(true).build()
+        }
+
+        val payload = dnsRequest.rawData
+        val packet = DatagramPacket(payload, payload.size, networkDNSAddressRepository.dnsAddress, DNS_PORT)
+        return requestDNSRepository.processDNS(packet)
+    }
+}