MODIFIED: ARP_SOURCE_FILE for parsing the packets.

Author: president-xd

src/parsers/arp.cpp

@@ -0,0 +1,40 @@
+#include "parsers/arp.h"
+#include <arpa/inet.h>
+#include <cstring>
+
+namespace parsers {
+
+ARPHeader parse_arp_header(const uint8_t* buffer, ssize_t length) {
+    ARPHeader header;
+
+    if (length < 28) {
+        throw std::runtime_error("ARP packet too short");
+    }
+
+    // Extract fixed fields
+    header.hardware_type = ntohs(*reinterpret_cast<const uint16_t*>(buffer));
+    header.protocol_type = ntohs(*reinterpret_cast<const uint16_t*>(buffer + 2));
+    header.hardware_size = *(buffer + 4);
+    header.protocol_size = *(buffer + 5);
+    header.operation     = ntohs(*reinterpret_cast<const uint16_t*>(buffer + 6));
+
+    // Extract addresses
+    const uint8_t* ptr = buffer + 8;
+    header.sender_mac.assign(ptr, ptr + 6);
+    ptr += 6;
+
+    char ip_buf[INET_ADDRSTRLEN];
+    std::memcpy(ip_buf, ptr, 4);
+    header.sender_ip = inet_ntoa(*reinterpret_cast<const in_addr*>(ptr));
+    ptr += 4;
+
+    header.target_mac.assign(ptr, ptr + 6);
+    ptr += 6;
+
+    std::memcpy(ip_buf, ptr, 4);
+    header.target_ip = inet_ntoa(*reinterpret_cast<const in_addr*>(ptr));
+
+    return header;
+}
+
+} // namespace parsers