MaxOS::net::InternetControlMessageProtocol Class Reference

Handles ICMP packets. More...

#include <icmp.h>

Inheritance diagram for MaxOS::net::InternetControlMessageProtocol:

Public Member Functions
	InternetControlMessageProtocol (InternetProtocolHandler *internet_protocol_handler, common::OutputStream *error_messages)
	Constructs an InternetControlMessageProtocol handler.
bool	handle_internet_protocol_payload (net::InternetProtocolAddress src_ip_be, net::InternetProtocolAddress dst_ip_be, uint8_t *payload_data, uint32_t size) final
	Called by the InternetProtocolProvider when a new packet has arrived.
void	request_echo_reply (uint32_t ip_be)
	Sends an ICMP echo request to the specified IP address.

Detailed Description

Handles ICMP packets.

Definition at line 41 of file icmp.h.

Constructor & Destructor Documentation

InternetControlMessageProtocol()

InternetControlMessageProtocol::InternetControlMessageProtocol	(	InternetProtocolHandler *	internet_protocol_handler,
		common::OutputStream *	error_messages
	)

Constructs an InternetControlMessageProtocol handler.

Parameters

internet_protocol_handler	The Internet protocol handler to use.
error_messages	The output stream to use for error messages.

Definition at line 21 of file icmp.cpp.

: IPV4PayloadHandler(internet_protocol_handler, 0x01)
{
    this -> error_messages = error_messages;
}

Member Function Documentation

handle_internet_protocol_payload()

bool InternetControlMessageProtocol::handle_internet_protocol_payload ( net::InternetProtocolAddress  src_ip_be, net::InternetProtocolAddress  dst_ip_be, uint8_t *  payload_data, uint32_t  size  )

finalvirtual

Called by the InternetProtocolProvider when a new packet has arrived.

Parameters

src_ip_be	The source IP address of the packet
dst_ip_be	The destination IP address of the packet
payload_data	The payload of the packet
size	The size of the payload

Returns

True if the packet is to be sent back to the sender, false otherwise

Todo:

Reply to ping requests

Implement the rest of the ICMP messages

Reimplemented from MaxOS::net::IPV4PayloadHandler.

Definition at line 43 of file icmp.cpp.

{
 
    error_messages -> write("ICMP received a packet\n");
 
    // Check if the size is at least the size of the header
    if(size < sizeof(ICMPHeader)){
        return false;
    }
 
    // Cast the payload to the ICMP header
    auto* icmp = (ICMPHeader*)payload_data;
 
    switch (icmp -> type) {
 
        case 0: // Echo reply
            break;
 
        case 8: // Echo request
 
            // Create a response
            icmp -> type = 0;                                                                                                                    // Echo reply
            icmp -> checksum = 0;                                                                                                                // Reset the checksum
            icmp -> checksum = InternetProtocolHandler::checksum((uint16_t*) &icmp, sizeof(ICMPHeader));             // Calculate the checksum
 
            return true;    //Send data back
 
    }
 
    return false;
 
}

References MaxOS::net::InternetProtocolHandler::checksum().

request_echo_reply()

void InternetControlMessageProtocol::request_echo_reply

(

uint32_t

ip_be

)

Sends an ICMP echo request to the specified IP address.

Parameters

ip_be

The IP address to send the request to

Definition at line 84 of file icmp.cpp.

                                                                      {
 
    error_messages -> write("ICMP: Sending echo request\n");
 
    ICMPHeader icmp = {};
    icmp.type = 8;                      // Echo request
    icmp.code = 0;                      // Code must be 0
    icmp.checksum = 0;                  // Checksum must be 0 to calculate it
    icmp.data = 0x69420;        // Data
 
    icmp.checksum = InternetProtocolHandler::checksum((uint16_t*) &icmp, sizeof(ICMPHeader));
 
    send(ip_be, (uint8_t*) &icmp, sizeof(ICMPHeader));
 
    error_messages -> write("ICMP: Echo request sent\n");
}

References MaxOS::net::InternetProtocolHandler::checksum(), and MaxOS::net::IPV4PayloadHandler::send().

---

The documentation for this class was generated from the following files:

• /home/runner/work/MaxOS/MaxOS/kernel/include/net/icmp.h
• /home/runner/work/MaxOS/MaxOS/kernel/src/net/icmp.cpp