void print_error(const std::string& hostname, IP4::addr server, const Error& err) {
printf("Error occurred when resolving IP address of %s with DNS server %s: %s\n", hostname.c_str(),
server.to_string().c_str(), err.what());
if (err.is_icmp()) {
auto* pd = dynamic_cast<const ICMP_error*>(&err);
printf("ICMP error type received when resolving %s: %s\n", hostname.c_str(), pd->icmp_type_str().c_str());
printf("ICMP error code received when resolving %s: %s\n", hostname.c_str(), pd->icmp_code_str().c_str());
}
}
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);
}
void print_success(const std::string& hostname, IP4::addr server, IP4::addr res) {
printf("Resolved IP address of %s with DNS server %s: %s\n", hostname.c_str(),
server.to_string().c_str(), res.to_string().c_str());
}