[PR] net/icmp: check src ip for icmp request message [nuttx]

[via GitHub]

HedongGao opened a new pull request, #17674:
URL: https://github.com/apache/nuttx/pull/17674

   
   ## Summary
   
   According to section 3.2.2.6 of RFC1122,  An ICMP Echo Request destined to 
an IP broadcast or IP multicast address MAY be silently discarded.
   
   ## Impact
   
   Check src ip for icmp request message, and drop the request message if src 
ip is broadcast/multicast.
   
   ## Testing
   
   Set up a SIM environment, ping the SIM from the host side, and verify that 
normal ping can reply.
   Then, write a Python script to construct a multicast/broadcast ICMP request 
message with the source IP address, where SIM does not respond.
   
   `
   from scapy.all import Ether, IP, ICMP, sendp
   
   SRC_MAC = "fa:b1:d9:6d:a0:d3"
   DST_MAC = "42:e1:c4:3f:48:dd"
   SRC_IP = "224.0.0.1"
   DST_IP = "10.0.1.2"
   INTERFACE = "eth0"
   
   def send_custom_icmp():
       try:
           ether_layer = Ether(src=SRC_MAC, dst=DST_MAC)
           ip_layer = IP(src=SRC_IP, dst=DST_IP, ttl=64)
           icmp_layer = ICMP(type=8, code=0)
           full_packet = ether_layer / ip_layer / icmp_layer
   
           sendp(full_packet, iface=INTERFACE, verbose=True)
           print("\n✅ ICMP packet sent successfully!")
           print(f"📄 Packet details:")
           print(f"   Source MAC: {SRC_MAC} | Destination MAC: {DST_MAC}")
           print(f"   Source IP: {SRC_IP} (Multicast) | Destination IP: 
{DST_IP}")
   
       except PermissionError:
           print("❌ Insufficient permissions! Run the script with 
administrator/root privileges (e.g., sudo python3 xxx.py)")
       except Exception as e:
           print(f"❌ Failed to send packet: {str(e)}")
           print("💡 Please check: 1. Correct network interface name 2. Valid 
MAC/IP format 3. Normal network connection")
   
   if __name__ == "__main__":
       send_custom_icmp()
   `
   


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