/**
* Check whether host's address is usable: routable and not bogus.
*/
gboolean
host_address_is_usable(const host_addr_t addr)
{
if (!host_addr_is_routable(addr))
return FALSE;
if (bogons_check(addr))
return FALSE;
return TRUE;
}
/**
* Notification from the socket layer that we got a new datagram.
*
* @param s the receiving socket (with s->addr and s->port set)
* @param data start of received data (not necessarily s->buf)
* @param len length of received data (not necessarily s->pos)
* @param truncated whether received datagram was truncated
*
* If `truncated' is true, then the message was too large for the
* socket buffer.
*/
void
udp_received(const gnutella_socket_t *s,
const void *data, size_t len, bool truncated)
{
gnutella_node_t *n;
bool bogus = FALSE;
bool dht = FALSE;
bool rudp = FALSE;
/*
* This must be regular Gnutella / DHT traffic.
*/
inet_udp_got_incoming(s->addr);
/*
* We need to identify semi-reliable UDP traffic early, because that
* traffic needs to go through the RX stack to reassemble the final
* payload out of the many fragments, or to process the acknowledgments.
*
* We have to apply heuristics however because the leading 8 bytes could
* be just a part of gnutella message (the first 8 bytes of a GUID).
* One thing is certain though: if the size is less than that of a a
* Gnutella header, it has to be semi-reliable UDP traffic...
*
* Because semi-reliable UDP uses small payloads, much smaller than our
* socket buffer, the datagram cannot be truncated.
*/
if (!truncated) {
enum udp_traffic utp;
rxdrv_t *rx;
utp = udp_intuit_traffic_type(s, data, len);
switch (utp) {
case GNUTELLA:
goto unreliable;
case RUDP:
rudp = TRUE;
gnet_stats_count_general(GNR_RUDP_RX_BYTES, len);
goto rudp; /* Don't account this message in UDP statistics */
case DHT:
dht = TRUE;
goto unreliable;
case UNKNOWN:
goto unknown;
case SEMI_RELIABLE_GTA:
case SEMI_RELIABLE_GND:
break;
}
/*
* We are going to treat this message a a semi-reliable UDP fragment.
*
* Account the size of the payload for traffic purposes, then redirect
* the message to the RX layer that reassembles and dispatches these
* messages.
*/
bws_udp_count_read(len, FALSE); /* We know it's not DHT traffic */
rx = udp_get_rx_semi_reliable(utp, s->addr, len);
if (rx != NULL) {
gnet_host_t from;
gnet_host_set(&from, s->addr, s->port);
ut_got_message(rx, data, len, &from);
}
return;
}
unknown:
/*
* Discriminate between Gnutella UDP and DHT messages, so that we
* can account received data with the proper bandwidth scheduler.
*/
if (len >= GTA_HEADER_SIZE)
dht = GTA_MSG_DHT == gnutella_header_get_function(data);
/* FALL THROUGH */
unreliable:
/*
* Account for Gnutella / DHT incoming UDP traffic.
*/
bws_udp_count_read(len, dht);
/* FALL THROUGH */
rudp:
/*
* The RUDP layer is used to implement firewalled-to-firewalled transfers
* via a mini TCP-like layer built on top of UDP. Therefore, it is used
* as the basis for higher-level connections (HTTP) and will have to be
* accounted for once the type of traffic is known, by upper layers, as
* part of the upload/download traffic.
*
* Of course, the higher levels will never see all the bytes that pass
* through, such as acknowledgments or retransmissions, but that is also
* the case for TCP-based sockets.
* --RAM, 2012-11-02.
*/
/*
* If we get traffic from a bogus IP (unroutable), warn, for now.
*/
if (bogons_check(s->addr)) {
bogus = TRUE;
if (GNET_PROPERTY(udp_debug)) {
g_warning("UDP %sdatagram (%zu byte%s) received from bogus IP %s",
truncated ? "truncated " : "",
len, 1 == len ? "" : "s",
host_addr_to_string(s->addr));
}
gnet_stats_inc_general(GNR_UDP_BOGUS_SOURCE_IP);
}
/*
* Get proper pseudo-node.
*
* These routines can return NULL if the address/port combination is
* not correct, but this will be handled by udp_is_valid_gnet().
*/
n = dht ? node_dht_get_addr_port(s->addr, s->port) :
node_udp_get_addr_port(s->addr, s->port);
if (!udp_is_valid_gnet(n, s, truncated, data, len))
return;
/*
* RUDP traffic does not go to the upper Gnutella processing layers.
*/
if (rudp) {
/* Not ready for prime time */
#if 0
rudp_handle_packet(s->addr, s->port. data, len);
#endif
return;
}
/*
* Process message as if it had been received from regular Gnet by
* another node, only we'll use a special "pseudo UDP node" as origin.
*/
if (GNET_PROPERTY(udp_debug) > 19 || (bogus && GNET_PROPERTY(udp_debug)))
g_debug("UDP got %s from %s%s", gmsg_infostr_full(data, len),
bogus ? "BOGUS " : "", host_addr_port_to_string(s->addr, s->port));
node_udp_process(n, s, data, len);
}
