resources/net/arp.cpp

   1 #include "arp.h"
   2 #include "mac_addr.h"
   3
   4 using namespace net;
   5
   6 void poll(volatile bool *value) {
   7         while (!*value) asm volatile("hlt");
   8 }
   9
  10 mac_addr arp::get_haddr(const ipv4_addr &ipaddr) {
  11         p<arp_table::arp_record> rec = table->get(ipaddr);
  12         if (rec.valid())
  13                 return rec->haddr;
  14
  15         p<arp_packet> pkg = new arp_packet;
  16
  17         pkg->htype = to_be16(ethernet);
  18         pkg->ptype = to_be16(ipv4);
  19
  20         pkg->hlen = mac_addr::in_bytes();
  21         pkg->plen = ipv4_addr::in_bytes();
  22
  23         pkg->oper = to_be16(request);
  24
  25         pkg->sha0 = my_haddr.first_be32();
  26         pkg->sha1 = my_haddr.last_be16();
  27         pkg->spa = my_paddr.to_be();
  28
  29         pkg->tha0 = 0;
  30         pkg->tha1 = 0;
  31         pkg->tpa = ipaddr.to_be();
  32
  33         mac_addr broadcast = mac_addr::from_be(0xffffffff, 0xffff);
  34         down->send_data(broadcast, et_arp, buffer::to_mem(pkg));
  35
  36         pkg.dispose();
  37
  38         rec = p<arp_table::arp_record>::invalid;
  39
  40         do {
  41                 poll(&received);
  42                 received = false;
  43                 rec = table->get(ipaddr);
  44         } while (!rec.valid());
  45
  46         return rec->haddr;
  47 }
  48
  49
  50 void arp::receive_packet(p<arp_packet> pkg) {
  51         if (from_be16(pkg->oper) == request) {
  52                 if (ipv4_addr::from_be(pkg->tpa) != my_paddr)
  53                         return;
  54
  55                 mac_addr mac = mac_addr::from_be(pkg->sha0, pkg->sha1);
  56
  57                 p<arp_packet> rpl = new arp_packet;
  58
  59                 rpl->htype = pkg->htype;
  60                 rpl->ptype = pkg->ptype;
  61
  62                 rpl->hlen = pkg->hlen;
  63                 rpl->plen = pkg->plen;
  64
  65                 rpl->oper = to_be16(reply);
  66
  67                 rpl->sha0 = my_haddr.first_be32();
  68                 rpl->sha1 = my_haddr.last_be16();
  69                 rpl->spa = my_paddr.to_be();
  70
  71                 rpl->tha0 = mac.first_be16();
  72                 rpl->tha1 = mac.last_be32();
  73                 rpl->tpa = pkg->spa;
  74
  75                 down->send_data(mac, et_arp, buffer::to_mem(rpl));
  76
  77                 rpl.dispose();
  78
  79         } else if (from_be16(pkg->oper) == reply) {
  80                 p<arp_table::arp_record> rec = new arp_table::arp_record;
  81                 rec->prot = from_be16(pkg->ptype);
  82                 rec->paddr = ipv4_addr::from_be(pkg->spa);
  83                 rec->haddr = mac_addr::from_be(pkg->sha0, pkg->sha1);
  84
  85                 table->add(rec);
  86                 received = true;
  87         }
  88 }
  89
  90
  91 void arp::receive_data(const buffer &x) {
  92         receive_packet(x.cast<arp_packet>());
  93 }