/**
* Free routine for the extended message blocks we send to the UDP layer.
*/
static void
g2_qh2_pmsg_free(pmsg_t *mb, void *arg)
{
struct g2_qh2_pmsg_info *pmi = arg;
gnutella_node_t *n;
g2_qh2_pmsg_info_check(pmi);
g_assert(pmsg_is_extended(mb));
if (pmsg_was_sent(mb))
goto done;
/*
* Message was unsent, probably because the UDP address in the /Q2 was
* wrong for some reason.
*
* If we're still connected to the hub which passed us this /Q2, then
* we can relay back the /QH2 to the hub and it will hopefully be able
* to deliver it back to the querying node.
*/
n = node_by_id(pmi->hub_id);
if (NULL == n) {
if (GNET_PROPERTY(g2_debug) > 1) {
g_debug("%s(): could not send %s, relaying hub is gone, dropping.",
G_STRFUNC, g2_msg_infostr_mb(mb));
}
gnet_stats_inc_general(GNR_UDP_G2_HITS_UNDELIVERED);
goto done;
} else {
pmsg_t *nmb;
if (GNET_PROPERTY(g2_debug) > 1) {
g_debug("%s(): could not send %s, giving back to %s for relaying",
G_STRFUNC, g2_msg_infostr_mb(mb), node_infostr(n));
}
nmb = pmsg_clone_plain(mb);
pmsg_clear_reliable(nmb);
g2_node_send(n, nmb);
gnet_stats_inc_general(GNR_UDP_G2_HITS_REROUTED_TO_HUB);
}
done:
nid_unref(pmi->hub_id);
pmi->magic = 0;
WFREE(pmi);
}
/**
* Send message (eslist iterator callback).
*
* @return TRUE if message was sent and freed up.
*/
static bool
udp_tx_desc_send(void *data, void *udata)
{
struct udp_tx_desc *txd = data;
udp_sched_t *us = udata;
unsigned prio;
udp_sched_check(us);
udp_tx_desc_check(txd);
if (us->used_all)
return FALSE;
/*
* Avoid flushing consecutive queued messages to the same destination,
* for regular (non-prioritary) messages.
*
* This serves two purposes:
*
* 1- It makes sure one single host does not capture all the available
* outgoing bandwidth.
*
* 2- It somehow delays consecutive packets to a given host thereby reducing
* flooding and hopefully avoiding saturation of its RX flow.
*/
prio = pmsg_prio(txd->mb);
if (PMSG_P_DATA == prio && hset_contains(us->seen, txd->to)) {
udp_sched_log(2, "%p: skipping mb=%p (%d bytes) to %s",
us, txd->mb, pmsg_size(txd->mb), gnet_host_to_string(txd->to));
return FALSE;
}
if (udp_sched_mb_sendto(us, txd->mb, txd->to, txd->tx, txd->cb)) {
if (PMSG_P_DATA == prio && pmsg_was_sent(txd->mb))
hset_insert(us->seen, atom_host_get(txd->to));
} else {
return FALSE; /* Unsent, leave it in the queue */
}
us->buffered = size_saturate_sub(us->buffered, pmsg_size(txd->mb));
udp_tx_desc_flag_release(txd, us);
return TRUE;
}
/**
* Free routine for query hit message.
*/
static void
dh_pmsg_free(pmsg_t *mb, void *arg)
{
struct dh_pmsg_info *pmi = arg;
const struct guid *muid;
dqhit_t *dh;
g_assert(pmsg_is_extended(mb));
muid = gnutella_header_get_muid(pmsg_start(mb));
dh = dh_locate(muid);
if (dh == NULL)
goto cleanup;
/*
* It can happen that an initial query hit comes and is queued for
* transmission, but the node is so clogged we don't actually send
* it before the entry expires in our tracking tables. When we later
* get the ACK that it was sent, we can therefore get obsolete data.
* Hence we're very careful updating the stats, and we can't assert
* that we're tracking everything correctly.
* --RAM, 2004-09-04
*/
if (pmsg_was_sent(mb))
dh->hits_sent += pmi->hits;
if (dh->msg_queued == 0) /* We did not expect this ACK */
goto cleanup;
dh->msg_queued--;
if (dh->hits_queued >= pmi->hits)
dh->hits_queued -= pmi->hits;
/* FALL THROUGH */
cleanup:
WFREE(pmi);
}
/**
* Enqueue message, which becomes owned by the queue.
*
* The data held in `to' is copied, so the structure can be reclaimed
* immediately by the caller.
*/
void
mq_udp_putq(mqueue_t *q, pmsg_t *mb, const gnet_host_t *to)
{
size_t size;
char *mbs;
uint8 function;
pmsg_t *mbe = NULL; /* Extended message with destination info */
bool error = FALSE;
mq_check_consistency(q);
dump_tx_udp_packet(to, mb);
again:
mq_check_consistency(q);
g_assert(mb);
g_assert(!pmsg_was_sent(mb));
g_assert(pmsg_is_unread(mb));
g_assert(q->ops == &mq_udp_ops); /* Is an UDP queue */
/*
* Trap messages enqueued whilst in the middle of an mq_clear() operation
* by marking them as sent and dropping them. Idem if queue was
* put in "discard" mode.
*/
if (q->flags & (MQ_CLEAR | MQ_DISCARD)) {
pmsg_mark_sent(mb); /* Let them think it was sent */
pmsg_free(mb); /* Drop message */
return;
}
mq_check(q, 0);
size = pmsg_size(mb);
if (size == 0) {
g_carp("%s: called with empty message", G_STRFUNC);
goto cleanup;
}
/*
* Protect against recursion: we must not invoke puthere() whilst in
* the middle of another putq() or we would corrupt the qlink array:
* Messages received during recursion are inserted into the qwait list
* and will be stuffed back into the queue when the initial putq() ends.
* --RAM, 2006-12-29
*/
if (q->putq_entered > 0) {
pmsg_t *extended;
if (debugging(20))
g_warning("%s: %s recursion detected (%u already pending)",
G_STRFUNC, mq_info(q), slist_length(q->qwait));
/*
* We insert extended messages into the waiting queue since we need
* the destination information as well.
*/
extended = mq_udp_attach_metadata(mb, to);
slist_append(q->qwait, extended);
return;
}
q->putq_entered++;
mbs = pmsg_start(mb);
function = gmsg_function(mbs);
gnet_stats_count_queued(q->node, function, mbs, size);
/*
* If queue is empty, attempt a write immediatly.
*/
if (q->qhead == NULL) {
ssize_t written;
if (pmsg_check(mb, q)) {
written = tx_sendto(q->tx_drv, mb, to);
} else {
gnet_stats_count_flowc(mbs, FALSE);
node_inc_txdrop(q->node); /* Dropped during TX */
written = (ssize_t) -1;
}
if ((ssize_t) -1 == written)
goto cleanup;
node_add_tx_given(q->node, written);
if ((size_t) written == size) {
if (GNET_PROPERTY(mq_udp_debug) > 5)
g_debug("MQ UDP sent %s",
gmsg_infostr_full(pmsg_start(mb), pmsg_written_size(mb)));
goto cleanup;
}
/*
* Since UDP respects write boundaries, the following can never
* happen in practice: either we write the whole datagram, or none
* of it.
*/
if (written > 0) {
g_warning(
"partial UDP write (%zu bytes) to %s for %zu-byte datagram",
written, gnet_host_to_string(to), size);
goto cleanup;
}
/* FALL THROUGH */
}
if (GNET_PROPERTY(mq_udp_debug) > 5)
g_debug("MQ UDP queued %s",
gmsg_infostr_full(pmsg_start(mb), pmsg_written_size(mb)));
/*
* Attach the destination information as metadata to the message, unless
* it is already known (possible only during unfolding of the queued data
* during re-entrant calls).
*
* This is later extracted via pmsg_get_metadata() on the extended
* message by the message queue to get the destination information.
*
* Then enqueue the extended message.
*/
if (NULL == mbe)
mbe = mq_udp_attach_metadata(mb, to);
q->cops->puthere(q, mbe, size);
mb = NULL;
/* FALL THROUGH */
cleanup:
if (mb) {
pmsg_free(mb);
mb = NULL;
}
/*
* When reaching that point with a zero putq_entered counter, it means
* we triggered an early error condition. Bail out.
*/
g_assert(q->putq_entered >= 0);
if (q->putq_entered == 0)
error = TRUE;
else
q->putq_entered--;
mq_check(q, 0);
/*
* If we're exiting here with no other putq() registered, then we must
* pop an item off the head of the list and iterate again.
*/
if (0 == q->putq_entered && !error) {
mbe = slist_shift(q->qwait);
if (mbe) {
struct mq_udp_info *mi = pmsg_get_metadata(mbe);
mb = mbe; /* An extended message "is-a" message */
to = &mi->to;
if (debugging(20))
g_warning(
"%s: %s flushing waiting to %s (%u still pending)",
G_STRFUNC, mq_info(q), gnet_host_to_string(to),
slist_length(q->qwait));
goto again;
}
}
return;
}
/**
* Free routine for our extended message blocks.
*/
static void
revent_pmsg_free(pmsg_t *mb, void *arg)
{
struct revent_pmsg_info *pmi = arg;
struct revent_ops *ops;
void *obj;
pmi_check(pmi);
g_assert(pmsg_is_extended(mb));
ops = pmi->ops;
/*
* It is possible that whilst the message was in the message queue,
* the operation was terminated. Therefore, we need to ensure that the
* recorded user is still alive.
*/
obj = (*ops->is_alive)(pmi->rid);
if (NULL == obj) {
if (*ops->debug > 2)
g_debug("DHT %s[%s] late UDP message %s",
ops->name, nid_to_string(&pmi->rid),
pmsg_was_sent(mb) ? "sending" : "dropping");
goto cleanup;
}
/*
* Signal message freeing, so that user structure can decrement the
* amount of pending messsages if necessary.
*/
if (ops->freeing_msg)
(*ops->freeing_msg)(obj);
/*
* If the RPC callback triggered before the UDP message queue could
* process the message on the way out, then we don't need to do anything
* as the RPC is already dead and has been processed as such...
*/
if (pmi->rpc_done)
goto cleanup;
pmi->rpi->pmi = NULL; /* Break x-ref as message was processed */
if (pmsg_was_sent(mb)) {
knode_t *kn = pmi->kn;
/*
* Message was successfully sent from the queue.
*/
kn->last_sent = tm_time();
if (ops->msg_sent)
(*ops->msg_sent)(obj, mb);
if (*ops->debug > 4)
g_debug("DHT %s[%s] sent %s (%d bytes) to %s, RTT=%u",
ops->name, nid_to_string(&pmi->rid),
kmsg_infostr(pmsg_phys_base(mb)),
pmsg_written_size(mb), knode_to_string(kn), kn->rtt);
} else {
knode_t *kn = pmi->kn;
guid_t *muid;
if (*ops->debug > 2)
g_debug("DHT %s[%s] message %s%u to %s dropped by UDP queue",
ops->name, nid_to_string(&pmi->rid),
ops->udata_name, pmi->rpi->udata,
knode_to_string(kn));
/*
* Message was not sent and dropped by the queue.
*/
if (ops->msg_dropped)
(*ops->msg_dropped)(obj, kn, mb);
/*
* Cancel the RPC, since the message was never sent out...
* The MUID is at the start of the message.
*/
g_assert(pmsg_written_size(mb) > GUID_RAW_SIZE);
muid = cast_to_guid_ptr(pmsg_phys_base(mb));
dht_rpc_cancel(muid);
if (ops->rpc_cancelled)
(*ops->rpc_cancelled)(obj, pmi->rpi->udata);
revent_rpi_free(pmi->rpi); /* Cancel does not invoke RPC callback */
}
cleanup:
revent_pmi_free(pmi);
}
