1 files changed, 171 insertions, 0 deletions

diff --git a/src/packet/packet.c b/src/packet/packet.c
new file mode 100644
index 0000000..9b1159d
--- /dev/null
+++ b/src/packet/packet.c
@@ -0,0 +1,171 @@
+#include "packet.h"
+#include "buffer.h"
+#include "header.h"
+#include "question.h"
+#include "record.h"
+
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+
+void read_packet(PacketBuffer* buffer, Packet* packet) {
+    read_header(buffer, &packet->header);
+    
+    packet->questions = malloc(sizeof(Question) * packet->header.questions);
+    for(uint16_t i = 0; i < packet->header.questions; i++) {
+        read_question(buffer, &packet->questions[i]);
+    }
+
+    packet->answers = malloc(sizeof(Record) * packet->header.answers);
+    for(uint16_t i = 0; i < packet->header.answers; i++) {
+        read_record(buffer, &packet->answers[i]);
+    }
+
+    packet->authorities = malloc(sizeof(Record) * packet->header.authoritative_entries);
+    for(uint16_t i = 0; i < packet->header.authoritative_entries; i++) {
+        read_record(buffer, &packet->authorities[i]);
+    }
+
+    packet->resources = malloc(sizeof(Record) * packet->header.resource_entries);
+    for(uint16_t i = 0; i < packet->header.resource_entries; i++) {
+        read_record(buffer, &packet->resources[i]);
+    }
+}
+
+void write_packet(PacketBuffer* buffer, Packet* packet) {
+    write_header(buffer, &packet->header);
+    
+    for(uint16_t i = 0; i < packet->header.questions; i++) {
+        write_question(buffer, &packet->questions[i]);
+    }
+
+    for(uint16_t i = 0; i < packet->header.answers; i++) {
+        write_record(buffer, &packet->answers[i]);
+    }
+
+    for(uint16_t i = 0; i < packet->header.authoritative_entries; i++) {
+        write_record(buffer, &packet->authorities[i]);
+    }
+
+    for(uint16_t i = 0; i < packet->header.resource_entries; i++) {
+        write_record(buffer, &packet->resources[i]);
+    }
+}
+
+void free_packet(Packet* packet) {
+    
+    for(uint16_t i = 0; i < packet->header.questions; i++) {
+        free_question(&packet->questions[i]);
+    }
+    free(packet->questions);
+
+    for(uint16_t i = 0; i < packet->header.answers; i++) {
+        free_record(&packet->answers[i]);
+    }
+    free(packet->answers);
+
+    for(uint16_t i = 0; i < packet->header.authoritative_entries; i++) {
+        free_record(&packet->authorities[i]);
+    }
+    free(packet->authorities);
+
+    for(uint16_t i = 0; i < packet->header.resource_entries; i++) {
+        free_record(&packet->resources[i]);
+    }
+    free(packet->resources);
+}
+
+bool get_random_a(Packet* packet, IpAddr* addr) {
+    for (uint16_t i = 0; i < packet->header.answers; i++) {
+        Record record = packet->answers[i];
+        if (record.type == A) {
+            create_ip_addr((char*) &record.data.a.addr, addr);
+            return true;
+        } else if (record.type == AAAA) {
+            create_ip_addr6((char*) &record.data.aaaa.addr, addr);
+            return true;
+        }
+    }
+    return false;
+}
+
+static bool ends_with(uint8_t* full, uint8_t* end) {
+    uint8_t check = end[0];
+    uint8_t len = full[0];
+
+    if (check > len) {
+        return false;
+    }
+
+    for(uint8_t i = 0; i < check; i++) {
+        if (end[check - 1 - i] != full[len - 1 - i]) {
+            return false;
+        }
+    }
+    
+    return true;
+}
+
+static bool equals(uint8_t* a, uint8_t* b) {
+    if (a[0] != b[0]) {
+        return false;
+    }
+
+    for(uint8_t i = 1; i < a[0] + 1; i++) {
+        if(a[i] != b[i]) {
+            return false;
+        }
+    }
+
+    return true;
+}
+
+bool get_resolved_ns(Packet* packet, uint8_t* qname, IpAddr* addr) {
+    for (uint16_t i = 0; i < packet->header.authoritative_entries; i++) {
+        Record record = packet->authorities[i];
+        if (record.type != NS) {
+            continue;
+        }
+
+        if(!ends_with(qname, record.domain)) {
+            continue;
+        }
+
+        for (uint16_t i = 0; i < packet->header.resource_entries; i++) {
+            Record resource = packet->resources[i];
+            if (!equals(record.data.ns.host, resource.domain)) {
+                continue;
+            }
+
+            if (resource.type == A) {
+                create_ip_addr((char*) &record.data.a.addr, addr);
+                return true;
+            } else if (resource.type == AAAA) {
+                create_ip_addr6((char*) &record.data.aaaa.addr, addr);
+                return true;
+            }
+        }
+    }
+    return false;
+}
+
+bool get_unresoled_ns(Packet* packet, uint8_t* qname, Question* question) {
+    for (uint16_t i = 0; i < packet->header.authoritative_entries; i++) {
+        Record record = packet->authorities[i];
+        if (record.type != NS) {
+            continue;
+        }
+
+        if(!ends_with(qname, record.domain)) {
+            continue;
+        }
+
+        uint8_t* host = record.data.ns.host;
+
+        question->qtype = NS;
+        question->domain = malloc(host[0] + 1);
+        memcpy(question->domain, host, host[0] + 1);
+        return true;
+    }
+    return false;
+}
\ No newline at end of file