Rolf Meyer
etherspam shows how to send an Ethernet packet. It simply sends ARP Who is messages for every IP.
main.cpp@0:852db76de235, 2009-09-04 (annotated)
- Committer:
- rolf
- Date:
- Fri Sep 04 12:25:06 2009 +0000
- Revision:
- 0:852db76de235
Who changed what in which revision?
| User | Revision | Line number | New contents of line |
|---|---|---|---|
| rolf | 0:852db76de235 | 1 | #include "mbed.h" // Importing the mbed classes and tools. |
| rolf | 0:852db76de235 | 2 | #include "Ethernet.h" |
| rolf | 0:852db76de235 | 3 | |
| rolf | 0:852db76de235 | 4 | using namespace mbed; |
| rolf | 0:852db76de235 | 5 | |
| rolf | 0:852db76de235 | 6 | __packed // A __packed struct to have no gaps between the members http://en.wikipedia.org/wiki/Data_structure_alignment |
| rolf | 0:852db76de235 | 7 | struct ethpkt { // Ethernet layer: http://en.wikipedia.org/wiki/Ethernet#Physical_layer |
| rolf | 0:852db76de235 | 8 | unsigned char dest[6]; // Destination MAC |
| rolf | 0:852db76de235 | 9 | unsigned char src[6]; // Source MAC |
| rolf | 0:852db76de235 | 10 | unsigned short type; // Payload type. ARP is 0x0806 |
| rolf | 0:852db76de235 | 11 | // ARP layer: http://en.wikipedia.org/wiki/Address_Resolution_Protocol |
| rolf | 0:852db76de235 | 12 | unsigned short hwtype; // Each data link layer protocol is assigned a number used in this field. Ethernet is 0x0001 |
| rolf | 0:852db76de235 | 13 | unsigned short proto; // Each protocol is assigned a number used in this field. IP is 0x0800. |
| rolf | 0:852db76de235 | 14 | unsigned char hwlen; // Length in bytes of a hardware address. Ethernet addresses are 6 bytes long. |
| rolf | 0:852db76de235 | 15 | unsigned char protolen; // Length in bytes of a logical address. IPv4 address are 4 bytes long. |
| rolf | 0:852db76de235 | 16 | unsigned short opcode; // Specifies the operation the sender is performing: |
| rolf | 0:852db76de235 | 17 | // 1 for request, 2 for reply, 3 for RARP request, and 4 for RARP reply. |
| rolf | 0:852db76de235 | 18 | unsigned char shwaddr[6]; // Hardware address of the sender. |
| rolf | 0:852db76de235 | 19 | unsigned char sipaddr[4]; // Protocol address of the sender. |
| rolf | 0:852db76de235 | 20 | unsigned char dhwaddr[6]; // Hardware address of the intended receiver. This field is ignored in requests. |
| rolf | 0:852db76de235 | 21 | unsigned char dipaddr[4]; // Protocol address of the intended receiver. |
| rolf | 0:852db76de235 | 22 | }; |
| rolf | 0:852db76de235 | 23 | |
| rolf | 0:852db76de235 | 24 | Ethernet eth; // The ethernet device |
| rolf | 0:852db76de235 | 25 | DigitalOut led4(LED4); // A LED for showing activity |
| rolf | 0:852db76de235 | 26 | |
| rolf | 0:852db76de235 | 27 | unsigned short htons(unsigned short n) { // Host short to network shor |
| rolf | 0:852db76de235 | 28 | return ((n & 0xff) << 8) | ((n & 0xff00) >> 8); // Byte swapping |
| rolf | 0:852db76de235 | 29 | } |
| rolf | 0:852db76de235 | 30 | |
| rolf | 0:852db76de235 | 31 | void send(const char *ipaddr) { |
| rolf | 0:852db76de235 | 32 | static char data[0x600]; // Packet buffer |
| rolf | 0:852db76de235 | 33 | const unsigned char arplen = 6; // Hardware address length |
| rolf | 0:852db76de235 | 34 | const unsigned char ethlen = 4; // IP address length |
| rolf | 0:852db76de235 | 35 | char hwaddr[arplen]; // Hardware address buffer |
| rolf | 0:852db76de235 | 36 | struct ethpkt *pkg = (struct ethpkt *) &data[0]; // Force the buffer to an ethpkg |
| rolf | 0:852db76de235 | 37 | unsigned char pos = arplen; // Hardware/IP address position |
| rolf | 0:852db76de235 | 38 | |
| rolf | 0:852db76de235 | 39 | eth.address(hwaddr); // Get own hardware address |
| rolf | 0:852db76de235 | 40 | |
| rolf | 0:852db76de235 | 41 | pkg->type = htons(0x0806); // Set type to ARP (0x0806) |
| rolf | 0:852db76de235 | 42 | pkg->hwtype = htons(0x0001); // Hardware type is Ethernet (0x0001) |
| rolf | 0:852db76de235 | 43 | pkg->proto = htons(0x0800); // Protocol is ARP Request (0x0800) |
| rolf | 0:852db76de235 | 44 | pkg->hwlen = arplen; // Hardware addresses are 6 Bytes long |
| rolf | 0:852db76de235 | 45 | pkg->protolen = ethlen; // And protocol addresses 4 Bytes |
| rolf | 0:852db76de235 | 46 | pkg->opcode = htons(0x0001); // Send: whois XX:XX:XX:XX:XX:XX? |
| rolf | 0:852db76de235 | 47 | |
| rolf | 0:852db76de235 | 48 | while(pos-- > 0) { // Write IP/MAC-Addresses (combined loop for all addresses) |
| rolf | 0:852db76de235 | 49 | pkg->src[pos] = hwaddr[pos]; // Set source MAC address to hwaddr on ethernet layer |
| rolf | 0:852db76de235 | 50 | pkg->dest[pos] = 0xFF; // Set destination MAC address to everybody (FF:FF:FF:FF:FF:FF) on ethernet layer |
| rolf | 0:852db76de235 | 51 | pkg->shwaddr[pos] = hwaddr[pos]; // Set source MAC address on ARP layer |
| rolf | 0:852db76de235 | 52 | pkg->dhwaddr[pos] = 0xFF; // Set destination MAC address on ARP layer |
| rolf | 0:852db76de235 | 53 | if(pos < ethlen) { // Check if we can copy IP addresses too. |
| rolf | 0:852db76de235 | 54 | pkg->sipaddr[pos] = 0xFF; // Set source ip address to 255.255.255.255 |
| rolf | 0:852db76de235 | 55 | pkg->dipaddr[pos] = ipaddr[pos]; // Set destination ip address to ipaddr |
| rolf | 0:852db76de235 | 56 | } |
| rolf | 0:852db76de235 | 57 | } |
| rolf | 0:852db76de235 | 58 | |
| rolf | 0:852db76de235 | 59 | eth.write(data, 60); // Write the package |
| rolf | 0:852db76de235 | 60 | eth.send(); // Send the package |
| rolf | 0:852db76de235 | 61 | } |
| rolf | 0:852db76de235 | 62 | // In this example we would like to make ARP requests to ask for every ip address. |
| rolf | 0:852db76de235 | 63 | int main() { // The programm starts here! |
| rolf | 0:852db76de235 | 64 | unsigned int i = 1; // The integer we use as counter and target IP address. |
| rolf | 0:852db76de235 | 65 | char *c = (char *)&i; // We cast the integer to an array of char c[4] to handle it as IP address. |
| rolf | 0:852db76de235 | 66 | |
| rolf | 0:852db76de235 | 67 | printf("Lowlevel Ethernet Spammer\n\n"); // Print out that the programm has been started. |
| rolf | 0:852db76de235 | 68 | |
| rolf | 0:852db76de235 | 69 | while(1) { // Do forever: |
| rolf | 0:852db76de235 | 70 | send(c); // Assamble and send our request. See eth_send function! |
| rolf | 0:852db76de235 | 71 | i++; // Increment counter. What will increment the IP (c[4]) address as well. |
| rolf | 0:852db76de235 | 72 | |
| rolf | 0:852db76de235 | 73 | led4 = 1; // Show activity, by blinking with led 4: |
| rolf | 0:852db76de235 | 74 | wait(0.02); // |
| rolf | 0:852db76de235 | 75 | led4 = 0; // Put the led on and wait for 0.2 seconds |
| rolf | 0:852db76de235 | 76 | wait(0.02); // Put the led off and wait for 0.2 seconds |
| rolf | 0:852db76de235 | 77 | } |
| rolf | 0:852db76de235 | 78 | } |