bool in_local_network(std::vector<ip_interface> const& net, address const& addr)
{
for (std::vector<ip_interface>::const_iterator i = net.begin()
, end(net.end()); i != end; ++i)
{
if (match_addr_mask(addr, i->interface_address, i->netmask))
return true;
}
return false;
}
tcp::endpoint utp_socket_manager::local_endpoint(address const& remote, error_code& ec) const
{
tcp::endpoint socket_ep = m_sock.local_endpoint(ec);
// first enumerate the routes in the routing table
if (time_now() - m_last_route_update > seconds(60))
{
m_last_route_update = time_now();
error_code ec;
m_routes = enum_routes(m_sock.get_io_service(), ec);
if (ec) return socket_ep;
}
if (m_routes.empty()) return socket_ep;
// then find the best match
ip_route* best = &m_routes[0];
for (std::vector<ip_route>::iterator i = m_routes.begin()
, end(m_routes.end()); i != end; ++i)
{
if (is_any(i->destination) && i->destination.is_v4() == remote.is_v4())
{
best = &*i;
continue;
}
if (match_addr_mask(remote, i->destination, i->netmask))
{
best = &*i;
continue;
}
}
// best now tells us which interface we would send over
// for this target. Now figure out what the local address
// is for that interface
if (time_now() - m_last_if_update > seconds(60))
{
m_last_if_update = time_now();
error_code ec;
m_interfaces = enum_net_interfaces(m_sock.get_io_service(), ec);
if (ec) return socket_ep;
}
for (std::vector<ip_interface>::iterator i = m_interfaces.begin()
, end(m_interfaces.end()); i != end; ++i)
{
if (i->interface_address.is_v4() != remote.is_v4())
continue;
if (strcmp(best->name, i->name) == 0)
return tcp::endpoint(i->interface_address, socket_ep.port());
}
return socket_ep;
}
void utp_socket_manager::mtu_for_dest(address const& addr, int& link_mtu, int& utp_mtu)
{
if (time_now() - m_last_route_update > seconds(60))
{
m_last_route_update = time_now();
error_code ec;
m_routes = enum_routes(m_sock.get_io_service(), ec);
}
int mtu = 0;
if (!m_routes.empty())
{
for (std::vector<ip_route>::iterator i = m_routes.begin()
, end(m_routes.end()); i != end; ++i)
{
if (!match_addr_mask(addr, i->destination, i->netmask)) continue;
// assume that we'll actually use the route with the largest
// MTU (seems like a reasonable assumption).
// this could however be improved by using the route metrics
// and the prefix length of the netmask to order the matches
if (mtu < i->mtu) mtu = i->mtu;
}
}
if (mtu == 0)
{
if (is_teredo(addr)) mtu = TORRENT_TEREDO_MTU;
else mtu = TORRENT_ETHERNET_MTU;
}
// clamp the MTU within reasonable bounds
if (mtu < TORRENT_INET_MIN_MTU) mtu = TORRENT_INET_MIN_MTU;
else if (mtu > TORRENT_INET_MAX_MTU) mtu = TORRENT_INET_MAX_MTU;
link_mtu = mtu;
mtu -= TORRENT_UDP_HEADER;
if (m_sock.get_proxy_settings().type == proxy_settings::socks5
|| m_sock.get_proxy_settings().type == proxy_settings::socks5_pw)
{
// this is for the IP layer
address proxy_addr = m_sock.proxy_addr().address();
if (proxy_addr.is_v4()) mtu -= TORRENT_IPV4_HEADER;
else mtu -= TORRENT_IPV6_HEADER;
// this is for the SOCKS layer
mtu -= TORRENT_SOCKS5_HEADER;
// the address field in the SOCKS header
if (addr.is_v4()) mtu -= 4;
else mtu -= 16;
}
else
{
if (addr.is_v4()) mtu -= TORRENT_IPV4_HEADER;
else mtu -= TORRENT_IPV6_HEADER;
}
utp_mtu = mtu;
}