void Arp::arp_resolve(Packet_ptr pckt) {
debug("<ARP RESOLVE> %s\n", pckt->next_hop().str().c_str());
const auto next_hop = pckt->next_hop();
await_resolution(std::move(pckt), next_hop);
auto req = static_unique_ptr_cast<PacketArp>(inet_.create_packet(sizeof(header)));
req->init(mac_, inet_.ip_addr());
req->set_dest_mac(Ethernet::BROADCAST_FRAME);
req->set_dest_ip(next_hop);
req->set_opcode(H_request);
// Stat increment requests sent
requests_tx_++;
linklayer_out_(std::move(req));
}
void Arp::transmit(Packet_ptr pckt, IP4::addr next_hop) {
Expects(pckt->size());
PRINT("<ARP -> physical> Transmitting %u bytes to %s\n",
(uint32_t) pckt->size(), next_hop.str().c_str());
MAC::Addr dest_mac;
if (next_hop == IP4::ADDR_BCAST) {
dest_mac = MAC::BROADCAST;
} else {
#ifdef ARP_PASSTHROUGH
extern MAC::Addr linux_tap_device;
dest_mac = linux_tap_device;
#else
// If we don't have a cached IP, perform address resolution
auto cache_entry = cache_.find(next_hop);
if (UNLIKELY(cache_entry == cache_.end())) {
PRINT("<ARP> No cache entry for IP %s. Resolving. \n", next_hop.to_string().c_str());
await_resolution(std::move(pckt), next_hop);
return;
}
// Get MAC from cache
dest_mac = cache_[next_hop].mac();
#endif
PRINT("<ARP> Found cache entry for IP %s -> %s \n",
next_hop.to_string().c_str(), dest_mac.to_string().c_str());
}
// Move chain to linklayer
linklayer_out_(std::move(pckt), dest_mac, Ethertype::IP4);
}
