resources/net/arp.cpp

   1 #include "arp.h"
   2 #include "mac_addr.h"
   3 #include "arp_packet.h"
   4
   5 using namespace net;
   6
   7 void poll(volatile bool *value) {
   8         while (!*value) asm volatile("nop");
   9 }
  10
  11 mac_addr arp::get_haddr(const ipv4_addr &ipaddr) {
  12         p<arp_table::arp_record> rec = table.get(ipaddr);
  13         if (rec.valid())
  14                 return rec->haddr;
  15
  16         p<arp_packet> pkg = new arp_packet;
  17         pkg->set_ptype(arp_packet::p_ipv4);
  18         pkg->set_htype(arp_packet::h_ethernet);
  19
  20         pkg->set_type(arp_packet::arp_request);
  21
  22         pkg->set_source_haddr(my_haddr);
  23         pkg->set_source_paddr(my_paddr);
  24
  25         pkg->set_target_paddr(ipaddr);
  26
  27         mac_addr broadcast = mac_addr::from_be(0xffffffff, 0xffff);
  28         down->send_data(broadcast, et_arp, pkg->generate());
  29
  30         pkg.dispose();
  31
  32         rec = p<arp_table::arp_record>::invalid;
  33
  34         do {
  35                 poll(&received);
  36                 received = false;
  37
  38                 rec = table.get(ipaddr);
  39         } while (!rec.valid());
  40
  41         return rec->haddr;
  42 }
  43
  44 void arp::receive_packet(p<arp_packet> pkg) {
  45         if (pkg->get_type() == arp_packet::arp_request) {
  46                 if (pkg->get_target_paddr() != my_paddr)
  47                         return;
  48
  49                 /* Add sender to ARP table */
  50                 arp_table::arp_record rec;
  51                 rec.prot = pkg->get_ptype();
  52                 rec.paddr = pkg->get_source_paddr();
  53                 rec.haddr = pkg->get_source_haddr();
  54
  55                 table.add(rec);
  56
  57                 p<arp_packet> rpl = new arp_packet;
  58
  59                 rpl->set_htype(pkg->get_htype());
  60                 rpl->set_ptype(pkg->get_ptype());
  61
  62                 rpl->set_type(arp_packet::arp_reply);
  63
  64                 rpl->set_source_haddr(my_haddr);
  65                 rpl->set_source_paddr(my_paddr);
  66
  67                 rpl->set_target_haddr(pkg->get_source_haddr());
  68                 rpl->set_target_paddr(pkg->get_source_paddr());
  69
  70                 down->send_data(pkg->get_source_haddr(), et_arp, rpl->generate());
  71
  72                 rpl.dispose();
  73
  74         } else if (pkg->get_type() == arp_packet::arp_reply) {
  75                 arp_table::arp_record rec;
  76                 rec.prot = pkg->get_ptype();
  77                 rec.paddr = pkg->get_source_paddr();
  78                 rec.haddr = pkg->get_source_haddr();
  79
  80                 table.add(rec);
  81                 received = true;
  82         }
  83 }
  84
  85 void arp::receive_data(const buffer &x) {
  86         receive_packet(new arp_packet(x));
  87 }