resources/net/icmp.cpp

   1 #include "icmp.h"
   2
   3 #include "libs/array.h"
   4
   5 using namespace net;
   6
   7 void icmp::ping(const ipv4_addr &addr) {
   8         p<icmp_packet> pkg = new icmp_packet;
   9         pkg->type = 8;
  10         pkg->code = 0;
  11         pkg->checksum = 0;
  12         pkg->id = to_be16(0xfeed);
  13         pkg->sequence = to_be16(1);
  14
  15         array<u8> data(36 - sizeof(icmp_packet));
  16         for (unsigned int i = 0; i < 36 - sizeof(icmp_packet); i++)
  17                 data[i] = '0' + i;
  18
  19         buffer buf = buffer::to_mem(pkg);
  20         buf += data.to_buffer();
  21
  22         array<u16> words = array<u16>::from_buffer(buf);
  23         u32 sum = 0;
  24         for (int i = 0; i < 18; i++)
  25                 sum += words[i];
  26
  27         sum = (sum & 0xffff) + (sum >> 16);
  28         sum += (sum >> 16);
  29
  30         buf.cast<icmp_packet>()->checksum = to_le16(~sum);
  31
  32         down->send_data(addr, ipv4::icmp, buf);
  33
  34         pkg.dispose();
  35 }
  36
  37 void icmp::receive(const ipv4_addr &addr, const buffer &data) {
  38         p<icmp_packet> request = data.cast<icmp_packet>();
  39
  40         if (request->type != 8 || request->code != 0)
  41                 return;
  42
  43         p<icmp_packet> pkg = new icmp_packet;
  44         pkg->type = 0;
  45         pkg->code = 0;
  46         pkg->checksum = 0;
  47         pkg->id = request->id;
  48         pkg->sequence = request->sequence;
  49
  50         buffer buf = buffer::to_mem(pkg);
  51         buf += data.cut_first(sizeof(icmp_packet));
  52
  53         array<u16> words = array<u16>::from_buffer(buf);
  54         u32 sum = 0;
  55         for (int i = 0; i < 18; i++)
  56                 sum += words[i];
  57
  58         sum = (sum & 0xffff) + (sum >> 16);
  59         sum += (sum >> 16);
  60
  61         buf.cast<icmp_packet>()->checksum = to_le16(~sum);
  62
  63         down->send_data(addr, ipv4::icmp, buf);
  64
  65         pkg.dispose();
  66 }