Rolf Meyer
/
ethspam
etherspam shows how to send an Ethernet packet. It simply sends ARP Who is messages for every IP.
Diff: main.cpp
- Revision:
- 0:852db76de235
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/main.cpp Fri Sep 04 12:25:06 2009 +0000 @@ -0,0 +1,78 @@ +#include "mbed.h" // Importing the mbed classes and tools. +#include "Ethernet.h" + +using namespace mbed; + +__packed // A __packed struct to have no gaps between the members http://en.wikipedia.org/wiki/Data_structure_alignment +struct ethpkt { // Ethernet layer: http://en.wikipedia.org/wiki/Ethernet#Physical_layer + unsigned char dest[6]; // Destination MAC + unsigned char src[6]; // Source MAC + unsigned short type; // Payload type. ARP is 0x0806 + // ARP layer: http://en.wikipedia.org/wiki/Address_Resolution_Protocol + unsigned short hwtype; // Each data link layer protocol is assigned a number used in this field. Ethernet is 0x0001 + unsigned short proto; // Each protocol is assigned a number used in this field. IP is 0x0800. + unsigned char hwlen; // Length in bytes of a hardware address. Ethernet addresses are 6 bytes long. + unsigned char protolen; // Length in bytes of a logical address. IPv4 address are 4 bytes long. + unsigned short opcode; // Specifies the operation the sender is performing: + // 1 for request, 2 for reply, 3 for RARP request, and 4 for RARP reply. + unsigned char shwaddr[6]; // Hardware address of the sender. + unsigned char sipaddr[4]; // Protocol address of the sender. + unsigned char dhwaddr[6]; // Hardware address of the intended receiver. This field is ignored in requests. + unsigned char dipaddr[4]; // Protocol address of the intended receiver. +}; + +Ethernet eth; // The ethernet device +DigitalOut led4(LED4); // A LED for showing activity + +unsigned short htons(unsigned short n) { // Host short to network shor + return ((n & 0xff) << 8) | ((n & 0xff00) >> 8); // Byte swapping +} + +void send(const char *ipaddr) { + static char data[0x600]; // Packet buffer + const unsigned char arplen = 6; // Hardware address length + const unsigned char ethlen = 4; // IP address length + char hwaddr[arplen]; // Hardware address buffer + struct ethpkt *pkg = (struct ethpkt *) &data[0]; // Force the buffer to an ethpkg + unsigned char pos = arplen; // Hardware/IP address position + + eth.address(hwaddr); // Get own hardware address + + pkg->type = htons(0x0806); // Set type to ARP (0x0806) + pkg->hwtype = htons(0x0001); // Hardware type is Ethernet (0x0001) + pkg->proto = htons(0x0800); // Protocol is ARP Request (0x0800) + pkg->hwlen = arplen; // Hardware addresses are 6 Bytes long + pkg->protolen = ethlen; // And protocol addresses 4 Bytes + pkg->opcode = htons(0x0001); // Send: whois XX:XX:XX:XX:XX:XX? + + while(pos-- > 0) { // Write IP/MAC-Addresses (combined loop for all addresses) + pkg->src[pos] = hwaddr[pos]; // Set source MAC address to hwaddr on ethernet layer + pkg->dest[pos] = 0xFF; // Set destination MAC address to everybody (FF:FF:FF:FF:FF:FF) on ethernet layer + pkg->shwaddr[pos] = hwaddr[pos]; // Set source MAC address on ARP layer + pkg->dhwaddr[pos] = 0xFF; // Set destination MAC address on ARP layer + if(pos < ethlen) { // Check if we can copy IP addresses too. + pkg->sipaddr[pos] = 0xFF; // Set source ip address to 255.255.255.255 + pkg->dipaddr[pos] = ipaddr[pos]; // Set destination ip address to ipaddr + } + } + + eth.write(data, 60); // Write the package + eth.send(); // Send the package +} + // In this example we would like to make ARP requests to ask for every ip address. +int main() { // The programm starts here! + unsigned int i = 1; // The integer we use as counter and target IP address. + char *c = (char *)&i; // We cast the integer to an array of char c[4] to handle it as IP address. + + printf("Lowlevel Ethernet Spammer\n\n"); // Print out that the programm has been started. + + while(1) { // Do forever: + send(c); // Assamble and send our request. See eth_send function! + i++; // Increment counter. What will increment the IP (c[4]) address as well. + + led4 = 1; // Show activity, by blinking with led 4: + wait(0.02); // + led4 = 0; // Put the led on and wait for 0.2 seconds + wait(0.02); // Put the led off and wait for 0.2 seconds + } +}