-
/*
This file is part of GNUnet.
Copyright (C) 2001-2017 GNUnet e.V.
* @author Christian Grothoff
*
* TODO:
- * - FIXME: send ACKs back to loopback clients!
- *
- * - introduce shutdown so we can have half-closed channels, modify
- * destroy to include MID to have FIN-ACK equivalents, etc.
- * - estimate max bandwidth using bursts and use to for CONGESTION CONTROL!
- * - check that '0xFFULL' really is sufficient for flow control!
- * - revisit handling of 'unreliable' traffic!
- * - revisit handling of 'out-of-order' option, especially in combination with/without 'reliable'.
- * - figure out flow control without ACKs (unreliable traffic!)
+ * - Congestion/flow control:
+ * + estimate max bandwidth using bursts and use to for CONGESTION CONTROL!
+ * (and figure out how/where to use this!)
+ * + figure out flow control without ACKs (unreliable traffic!)
+ * - revisit handling of 'unbuffered' traffic!
+ * (need to push down through tunnel into connection selection)
+ * - revisit handling of 'buffered' traffic: 4 is a rather small buffer; maybe
+ * reserve more bits in 'options' to allow for buffer size control?
*/
#include "platform.h"
#include "gnunet_util_lib.h"
*/
#define TIMEOUT_CLOSED_PORT GNUNET_TIME_relative_multiply(GNUNET_TIME_UNIT_SECONDS, 30)
+/**
+ * How long do we wait at least before retransmitting ever?
+ */
+#define MIN_RTT_DELAY GNUNET_TIME_relative_multiply(GNUNET_TIME_UNIT_MILLISECONDS, 75)
+
+/**
+ * Maximum message ID into the future we accept for out-of-order messages.
+ * If the message is more than this into the future, we drop it. This is
+ * important both to detect values that are actually in the past, as well
+ * as to limit adversarially triggerable memory consumption.
+ *
+ * Note that right now we have "max_pending_messages = 4" hard-coded in
+ * the logic below, so a value of 4 would suffice here. But we plan to
+ * allow larger windows in the future...
+ */
+#define MAX_OUT_OF_ORDER_DISTANCE 1024
+
/**
- * All the states a connection can be in.
+ * All the states a channel can be in.
*/
enum CadetChannelState
{
CADET_CHANNEL_NEW,
/**
- * Connection create message sent, waiting for ACK.
+ * Channel is to a port that is not open, we're waiting for the
+ * port to be opened.
+ */
+ CADET_CHANNEL_LOOSE,
+
+ /**
+ * CHANNEL_OPEN message sent, waiting for CHANNEL_OPEN_ACK.
*/
CADET_CHANNEL_OPEN_SENT,
*/
struct CadetTunnelQueueEntry *qe;
+ /**
+ * Data message we are trying to send.
+ */
+ struct GNUNET_CADET_ChannelAppDataMessage *data_message;
+
/**
* How soon should we retry if we fail to get an ACK?
* Messages in the queue are sorted by this value.
struct GNUNET_TIME_Relative retry_delay;
/**
- * Data message we are trying to send.
+ * Time when we first successfully transmitted the message
+ * (that is, set @e num_transmissions to 1).
*/
- struct GNUNET_CADET_ChannelAppDataMessage *data_message;
+ struct GNUNET_TIME_Absolute first_transmission_time;
+
+ /**
+ * Identifier of the connection that this message took when it
+ * was first transmitted. Only useful if @e num_transmissions is 1.
+ */
+ struct GNUNET_CADET_ConnectionTunnelIdentifier connection_taken;
+
+ /**
+ * How often was this message transmitted? #GNUNET_SYSERR if there
+ * was an error transmitting the message, #GNUNET_NO if it was not
+ * yet transmitted ever, otherwise the number of (re) transmissions.
+ */
+ int num_transmissions;
};
*/
struct GNUNET_CADET_ClientChannelNumber ccn;
+ /**
+ * Number of entries currently in @a head_recv DLL.
+ */
+ unsigned int num_recv;
+
/**
* Can we send data to the client?
*/
*/
struct GNUNET_TIME_Relative retry_time;
- /**
- * How long does it usually take to get an ACK.
- */
- struct GNUNET_TIME_Relative expected_delay;
-
/**
* Bitfield of already-received messages past @e mid_recv.
*/
*/
enum CadetChannelState state;
+ /**
+ * Count how many ACKs we skipped, used to prevent long
+ * sequences of ACK skipping.
+ */
+ unsigned int skip_ack_series;
+
/**
* Is the tunnel bufferless (minimum latency)?
*/
GNUNET_CONTAINER_DLL_remove (ccc->head_recv,
ccc->tail_recv,
com);
+ ccc->num_recv--;
GNUNET_MQ_discard (com->env);
GNUNET_free (com);
}
* create message. Delays for a bit until we retry.
*
* @param cls our `struct CadetChannel`.
+ * @param cid identifier of the connection within the tunnel, NULL
+ * if transmission failed
*/
static void
-channel_open_sent_cb (void *cls)
+channel_open_sent_cb (void *cls,
+ const struct GNUNET_CADET_ConnectionTunnelIdentifier *cid)
{
struct CadetChannel *ch = cls;
msgcc.port = ch->port;
msgcc.ctn = ch->ctn;
ch->state = CADET_CHANNEL_OPEN_SENT;
+ if (NULL != ch->last_control_qe)
+ GCT_send_cancel (ch->last_control_qe);
ch->last_control_qe = GCT_send (ch->t,
&msgcc.header,
&channel_open_sent_cb,
ch);
+ GNUNET_assert (NULL == ch->retry_control_task);
}
if (NULL == c)
{
/* port closed, wait for it to possibly open */
+ ch->state = CADET_CHANNEL_LOOSE;
(void) GNUNET_CONTAINER_multihashmap_put (loose_channels,
port,
ch,
}
else
{
- ch->dest = GNUNET_new (struct CadetChannelClient);
- ch->dest->c = c;
- ch->dest->client_ready = GNUNET_YES;
GCCH_bind (ch,
- ch->dest->c);
+ c);
}
}
else
if (NULL == c)
{
/* port closed, wait for it to possibly open */
+ ch->state = CADET_CHANNEL_LOOSE;
(void) GNUNET_CONTAINER_multihashmap_put (loose_channels,
port,
ch,
GNUNET_CONTAINER_MULTIHASHMAPOPTION_MULTIPLE);
+ GNUNET_assert (NULL == ch->retry_control_task);
ch->retry_control_task
= GNUNET_SCHEDULER_add_delayed (TIMEOUT_CLOSED_PORT,
&timeout_closed_cb,
* ACKs for ACKs ;-).
*
* @param cls our `struct CadetChannel`.
+ * @param cid identifier of the connection within the tunnel, NULL
+ * if transmission failed
*/
static void
-send_ack_cb (void *cls)
+send_ack_cb (void *cls,
+ const struct GNUNET_CADET_ConnectionTunnelIdentifier *cid)
{
struct CadetChannel *ch = cls;
{
struct GNUNET_CADET_ChannelDataAckMessage msg;
+ if (GNUNET_NO == ch->reliable)
+ return; /* no ACKs */
msg.header.type = htons (GNUNET_MESSAGE_TYPE_CADET_CHANNEL_APP_DATA_ACK);
msg.header.size = htons (sizeof (msg));
msg.ctn = ch->ctn;
- msg.mid.mid = htonl (ntohl (ch->mid_recv.mid) - 1);
+ msg.mid.mid = htonl (ntohl (ch->mid_recv.mid));
msg.futures = GNUNET_htonll (ch->mid_futures);
+ LOG (GNUNET_ERROR_TYPE_DEBUG,
+ "Sending DATA_ACK %u:%llX via %s\n",
+ (unsigned int) ntohl (msg.mid.mid),
+ (unsigned long long) ch->mid_futures,
+ GCCH_2s (ch));
if (NULL != ch->last_control_qe)
GCT_send_cancel (ch->last_control_qe);
ch->last_control_qe = GCT_send (ch->t,
struct CadetChannel *ch = cls;
struct GNUNET_CADET_ChannelManageMessage msg;
+ ch->retry_control_task = NULL;
LOG (GNUNET_ERROR_TYPE_DEBUG,
"Sending CHANNEL_OPEN_ACK on %s\n",
GCCH_2s (ch));
- ch->retry_control_task = NULL;
msg.header.type = htons (GNUNET_MESSAGE_TYPE_CADET_CHANNEL_OPEN_ACK);
msg.header.size = htons (sizeof (msg));
msg.reserved = htonl (0);
* #GNUNET_MESSAGE_TYPE_CADET_CHANNEL_OPEN_ACK.
*
* @param ch channel that got the duplicate open
+ * @param cti identifier of the connection that delivered the message
*/
void
-GCCH_handle_duplicate_open (struct CadetChannel *ch)
+GCCH_handle_duplicate_open (struct CadetChannel *ch,
+ const struct GNUNET_CADET_ConnectionTunnelIdentifier *cti)
{
if (NULL == ch->dest)
{
LOG (GNUNET_ERROR_TYPE_DEBUG,
- "Ignoring duplicate channel OPEN on %s: port is closed\n",
+ "Ignoring duplicate CHANNEL_OPEN on %s: port is closed\n",
GCCH_2s (ch));
return;
}
if (NULL != ch->retry_control_task)
{
LOG (GNUNET_ERROR_TYPE_DEBUG,
- "Ignoring duplicate channel OPEN on %s: control message is pending\n",
+ "Ignoring duplicate CHANNEL_OPEN on %s: control message is pending\n",
GCCH_2s (ch));
return;
}
LOG (GNUNET_ERROR_TYPE_DEBUG,
- "Retransmitting OPEN_ACK on %s\n",
+ "Retransmitting CHANNEL_OPEN_ACK on %s\n",
GCCH_2s (ch));
ch->retry_control_task
= GNUNET_SCHEDULER_add_now (&send_open_ack,
struct GNUNET_CADET_LocalAck *ack;
struct CadetChannelClient *ccc;
+ ccc = (GNUNET_YES == to_owner) ? ch->owner : ch->dest;
+ if (NULL == ccc)
+ {
+ /* This can happen if we are just getting ACKs after
+ our local client already disconnected. */
+ GNUNET_assert (GNUNET_YES == ch->destroy);
+ return;
+ }
env = GNUNET_MQ_msg (ack,
GNUNET_MESSAGE_TYPE_CADET_LOCAL_ACK);
- ccc = (GNUNET_YES == to_owner) ? ch->owner : ch->dest;
ack->ccn = ccc->ccn;
LOG (GNUNET_ERROR_TYPE_DEBUG,
- "Sending CADET_LOCAL_ACK to %s (%s) at ccn %X\n",
+ "Sending CADET_LOCAL_ACK to %s (%s) at ccn %X (%u/%u pending)\n",
GSC_2s (ccc->c),
(GNUNET_YES == to_owner) ? "owner" : "dest",
- ntohl (ack->ccn.channel_of_client));
+ ntohl (ack->ccn.channel_of_client),
+ ch->pending_messages,
+ ch->max_pending_messages);
GSC_send_to_client (ccc->c,
env);
}
if (ch->out_of_order)
options |= GNUNET_CADET_OPTION_OUT_OF_ORDER;
cccd = GNUNET_new (struct CadetChannelClient);
+ GNUNET_assert (NULL == ch->dest);
ch->dest = cccd;
cccd->c = c;
cccd->client_ready = GNUNET_YES;
if (GNUNET_YES == ch->is_loopback)
{
ch->state = CADET_CHANNEL_OPEN_SENT;
- GCCH_handle_channel_open_ack (ch);
+ GCCH_handle_channel_open_ack (ch,
+ NULL);
}
else
{
/* notify other peer that we accepted the connection */
+ ch->state = CADET_CHANNEL_READY;
ch->retry_control_task
= GNUNET_SCHEDULER_add_now (&send_open_ack,
ch);
}
+/**
+ * One of our clients has disconnected, tell the other one that we
+ * are finished. Done asynchronously to avoid concurrent modification
+ * issues if this is the same client.
+ *
+ * @param cls the `struct CadetChannel` where one of the ends is now dead
+ */
+static void
+signal_remote_destroy_cb (void *cls)
+{
+ struct CadetChannel *ch = cls;
+ struct CadetChannelClient *ccc;
+
+ /* Find which end is left... */
+ ch->retry_control_task = NULL;
+ ccc = (NULL != ch->owner) ? ch->owner : ch->dest;
+ GSC_handle_remote_channel_destroy (ccc->c,
+ ccc->ccn,
+ ch);
+ channel_destroy (ch);
+}
+
+
/**
* Destroy locally created channel. Called by the local client, so no
* need to tell the client.
channel_destroy (ch);
return;
}
- if ( (NULL != ch->head_sent) ||
- (NULL != ch->owner) ||
- (NULL != ch->dest) )
+ if ( (NULL != ch->head_sent) &&
+ ( (NULL != ch->owner) ||
+ (NULL != ch->dest) ) )
{
/* Wait for other end to destroy us as well,
and otherwise allow send queue to be transmitted first */
ch->destroy = GNUNET_YES;
return;
}
- /* If the we ever sent the CHANNEL_CREATE, we need to send a destroy message. */
- if (CADET_CHANNEL_NEW != ch->state)
- GCT_send_channel_destroy (ch->t,
- ch->ctn);
+ if ( (GNUNET_YES == ch->is_loopback) &&
+ ( (NULL != ch->owner) ||
+ (NULL != ch->dest) ) )
+ {
+ if (NULL != ch->retry_control_task)
+ GNUNET_SCHEDULER_cancel (ch->retry_control_task);
+ ch->retry_control_task
+ = GNUNET_SCHEDULER_add_now (&signal_remote_destroy_cb,
+ ch);
+ return;
+ }
+ if (GNUNET_NO == ch->is_loopback)
+ {
+ /* If the we ever sent the CHANNEL_CREATE, we need to send a destroy message. */
+ switch (ch->state)
+ {
+ case CADET_CHANNEL_NEW:
+ /* We gave up on a channel that we created as a client to a remote
+ target, but that never went anywhere. Nothing to do here. */
+ break;
+ case CADET_CHANNEL_LOOSE:
+ GSC_drop_loose_channel (&ch->port,
+ ch);
+ break;
+ default:
+ GCT_send_channel_destroy (ch->t,
+ ch->ctn);
+ }
+ }
/* Nothing left to do, just finish destruction */
channel_destroy (ch);
}
* (the port is open on the other side). Begin transmissions.
*
* @param ch channel to destroy
+ * @param cti identifier of the connection that delivered the message
*/
void
-GCCH_handle_channel_open_ack (struct CadetChannel *ch)
+GCCH_handle_channel_open_ack (struct CadetChannel *ch,
+ const struct GNUNET_CADET_ConnectionTunnelIdentifier *cti)
{
switch (ch->state)
{
/* this should be impossible */
GNUNET_break (0);
break;
+ case CADET_CHANNEL_LOOSE:
+ /* This makes no sense. */
+ GNUNET_break_op (0);
+ break;
case CADET_CHANNEL_OPEN_SENT:
if (NULL == ch->owner)
{
/**
* Test if element @a e1 comes before element @a e2.
*
- * TODO: use opportunity to create generic list insertion sort
- * logic in container!
- *
- * @param cls closure, our `struct CadetChannel`
- * @param e1 an element of to sort
- * @param e2 another element to sort
+ * @param cls closure, to a flag where we indicate duplicate packets
+ * @param m1 a message of to sort
+ * @param m2 another message to sort
* @return #GNUNET_YES if @e1 < @e2, otherwise #GNUNET_NO
*/
static int
is_before (void *cls,
- void *e1,
- void *e2)
+ struct CadetOutOfOrderMessage *m1,
+ struct CadetOutOfOrderMessage *m2)
{
- struct CadetOutOfOrderMessage *m1 = e1;
- struct CadetOutOfOrderMessage *m2 = e2;
+ int *duplicate = cls;
uint32_t v1 = ntohl (m1->mid.mid);
uint32_t v2 = ntohl (m2->mid.mid);
uint32_t delta;
- delta = v1 - v2;
+ delta = v2 - v1;
+ if (0 == delta)
+ *duplicate = GNUNET_YES;
if (delta > (uint32_t) INT_MAX)
{
/* in overflow range, we can safely assume we wrapped around */
}
else
{
+ /* result is small, thus v2 > v1, thus m1 < m2 */
return GNUNET_YES;
}
}
* and send an ACK to the other end (once flow control allows it!)
*
* @param ch channel that got data
+ * @param cti identifier of the connection that delivered the message
* @param msg message that was received
*/
void
GCCH_handle_channel_plaintext_data (struct CadetChannel *ch,
+ const struct GNUNET_CADET_ConnectionTunnelIdentifier *cti,
const struct GNUNET_CADET_ChannelAppDataMessage *msg)
{
struct GNUNET_MQ_Envelope *env;
struct GNUNET_CADET_LocalData *ld;
struct CadetChannelClient *ccc;
- struct CadetOutOfOrderMessage *com;
size_t payload_size;
+ struct CadetOutOfOrderMessage *com;
+ int duplicate;
+ uint32_t mid_min;
+ uint32_t mid_max;
+ uint32_t mid_msg;
+ uint32_t delta;
GNUNET_assert (GNUNET_NO == ch->is_loopback);
if ( (GNUNET_YES == ch->destroy) &&
LOG (GNUNET_ERROR_TYPE_DEBUG,
"Dropping incoming payload on %s as this end is already closed\n",
GCCH_2s (ch));
- /* FIXME: send back ACK/NACK/Closed notification
- to stop retransmissions! */
+ /* send back DESTROY notification to stop further retransmissions! */
+ GCT_send_channel_destroy (ch->t,
+ ch->ctn);
return;
}
payload_size = ntohs (msg->header.size) - sizeof (*msg);
(msg->mid.mid == ch->mid_recv.mid) ) )
{
LOG (GNUNET_ERROR_TYPE_DEBUG,
- "Giving %u bytes of payload from %s to client %s\n",
+ "Giving %u bytes of payload with MID %u from %s to client %s\n",
(unsigned int) payload_size,
+ ntohl (msg->mid.mid),
GCCH_2s (ch),
GSC_2s (ccc->c));
ccc->client_ready = GNUNET_NO;
env);
ch->mid_recv.mid = htonl (1 + ntohl (ch->mid_recv.mid));
ch->mid_futures >>= 1;
+ send_channel_data_ack (ch);
+ return;
}
- else
- {
- /* FIXME-SECURITY: if the element is WAY too far ahead,
- drop it (can't buffer too much!) */
- LOG (GNUNET_ERROR_TYPE_DEBUG,
- "Queuing %s payload of %u bytes on %s (mid %u, need %u first)\n",
- (GNUNET_YES == ccc->client_ready)
- ? "out-of-order"
- : "client-not-ready",
- (unsigned int) payload_size,
- GCCH_2s (ch),
- ntohl (msg->mid.mid),
- ntohl (ch->mid_recv.mid));
- com = GNUNET_new (struct CadetOutOfOrderMessage);
- com->mid = msg->mid;
- com->env = env;
- /* sort into list ordered by "is_before" */
- if ( (NULL == ccc->head_recv) ||
- (GNUNET_YES == is_before (ch,
- com,
- ccc->head_recv)) )
+ if (GNUNET_YES == ch->reliable)
+ {
+ /* check if message ought to be dropped because it is ancient/too distant/duplicate */
+ mid_min = ntohl (ch->mid_recv.mid);
+ mid_max = mid_min + ch->max_pending_messages;
+ mid_msg = ntohl (msg->mid.mid);
+ if ( ( (uint32_t) (mid_msg - mid_min) > ch->max_pending_messages) ||
+ ( (uint32_t) (mid_max - mid_msg) > ch->max_pending_messages) )
{
- GNUNET_CONTAINER_DLL_insert (ccc->head_recv,
- ccc->tail_recv,
- com);
+ LOG (GNUNET_ERROR_TYPE_DEBUG,
+ "%s at %u drops ancient or far-future message %u\n",
+ GCCH_2s (ch),
+ (unsigned int) mid_min,
+ ntohl (msg->mid.mid));
+
+ GNUNET_STATISTICS_update (stats,
+ "# duplicate DATA (ancient or future)",
+ 1,
+ GNUNET_NO);
+ GNUNET_MQ_discard (env);
+ send_channel_data_ack (ch);
+ return;
}
- else
+ /* mark bit for future ACKs */
+ delta = mid_msg - mid_min - 1; /* overflow/underflow are OK here */
+ if (delta < 64)
{
- struct CadetOutOfOrderMessage *pos;
-
- for (pos = ccc->head_recv;
- NULL != pos;
- pos = pos->next)
+ if (0 != (ch->mid_futures & (1LLU << delta)))
{
- if (GNUNET_YES !=
- is_before (NULL,
- pos,
- com))
- break;
+ /* Duplicate within the queue, drop also */
+ LOG (GNUNET_ERROR_TYPE_DEBUG,
+ "Duplicate payload of %u bytes on %s (mid %u) dropped\n",
+ (unsigned int) payload_size,
+ GCCH_2s (ch),
+ ntohl (msg->mid.mid));
+ GNUNET_STATISTICS_update (stats,
+ "# duplicate DATA",
+ 1,
+ GNUNET_NO);
+ GNUNET_MQ_discard (env);
+ send_channel_data_ack (ch);
+ return;
}
- if (NULL == pos)
- GNUNET_CONTAINER_DLL_insert_tail (ccc->head_recv,
- ccc->tail_recv,
- com);
- else
- GNUNET_CONTAINER_DLL_insert_after (ccc->head_recv,
- ccc->tail_recv,
- com,
- pos->prev);
+ ch->mid_futures |= (1LLU << delta);
+ LOG (GNUNET_ERROR_TYPE_DEBUG,
+ "Marked bit %llX for mid %u (base: %u); now: %llX\n",
+ (1LLU << delta),
+ mid_msg,
+ mid_min,
+ ch->mid_futures);
}
}
+ else /* ! ch->reliable */
+ {
+ /* Channel is unreliable, so we do not ACK. But we also cannot
+ allow buffering everything, so check if we have space... */
+ if (ccc->num_recv >= ch->max_pending_messages)
+ {
+ struct CadetOutOfOrderMessage *drop;
+
+ /* Yep, need to drop. Drop the oldest message in
+ the buffer. */
+ LOG (GNUNET_ERROR_TYPE_DEBUG,
+ "Queue full due slow client on %s, dropping oldest message\n",
+ GCCH_2s (ch));
+ GNUNET_STATISTICS_update (stats,
+ "# messages dropped due to slow client",
+ 1,
+ GNUNET_NO);
+ drop = ccc->head_recv;
+ GNUNET_CONTAINER_DLL_remove (ccc->head_recv,
+ ccc->tail_recv,
+ drop);
+ ccc->num_recv--;
+ GNUNET_MQ_discard (drop->env);
+ GNUNET_free (drop);
+ }
+ }
+
+ /* Insert message into sorted out-of-order queue */
+ com = GNUNET_new (struct CadetOutOfOrderMessage);
+ com->mid = msg->mid;
+ com->env = env;
+ duplicate = GNUNET_NO;
+ GNUNET_CONTAINER_DLL_insert_sorted (struct CadetOutOfOrderMessage,
+ is_before,
+ &duplicate,
+ ccc->head_recv,
+ ccc->tail_recv,
+ com);
+ ccc->num_recv++;
+ if (GNUNET_YES == duplicate)
+ {
+ /* Duplicate within the queue, drop also (this is not covered by
+ the case above if "delta" >= 64, which could be the case if
+ max_pending_messages is also >= 64 or if our client is unready
+ and we are seeing retransmissions of the message our client is
+ blocked on. */
+ LOG (GNUNET_ERROR_TYPE_DEBUG,
+ "Duplicate payload of %u bytes on %s (mid %u) dropped\n",
+ (unsigned int) payload_size,
+ GCCH_2s (ch),
+ ntohl (msg->mid.mid));
+ GNUNET_STATISTICS_update (stats,
+ "# duplicate DATA",
+ 1,
+ GNUNET_NO);
+ GNUNET_CONTAINER_DLL_remove (ccc->head_recv,
+ ccc->tail_recv,
+ com);
+ ccc->num_recv--;
+ GNUNET_MQ_discard (com->env);
+ GNUNET_free (com);
+ send_channel_data_ack (ch);
+ return;
+ }
+ LOG (GNUNET_ERROR_TYPE_DEBUG,
+ "Queued %s payload of %u bytes on %s-%X(%p) (mid %u, need %u first)\n",
+ (GNUNET_YES == ccc->client_ready)
+ ? "out-of-order"
+ : "client-not-ready",
+ (unsigned int) payload_size,
+ GCCH_2s (ch),
+ ntohl (ccc->ccn.channel_of_client),
+ ccc,
+ ntohl (msg->mid.mid),
+ ntohl (ch->mid_recv.mid));
+ /* NOTE: this ACK we _could_ skip, as the packet is out-of-order and
+ the sender may already be transmitting the previous one. Needs
+ experimental evaluation to see if/when this ACK helps or
+ hurts. (We might even want another option.) */
+ send_channel_data_ack (ch);
+}
+
+
+/**
+ * Function called once the tunnel has sent one of our messages.
+ * If the message is unreliable, simply frees the `crm`. If the
+ * message was reliable, calculate retransmission time and
+ * wait for ACK (or retransmit).
+ *
+ * @param cls the `struct CadetReliableMessage` that was sent
+ * @param cid identifier of the connection within the tunnel, NULL
+ * if transmission failed
+ */
+static void
+data_sent_cb (void *cls,
+ const struct GNUNET_CADET_ConnectionTunnelIdentifier *cid);
+
+
+/**
+ * We need to retry a transmission, the last one took too long to
+ * be acknowledged.
+ *
+ * @param cls the `struct CadetChannel` where we need to retransmit
+ */
+static void
+retry_transmission (void *cls)
+{
+ struct CadetChannel *ch = cls;
+ struct CadetReliableMessage *crm = ch->head_sent;
+
+ ch->retry_data_task = NULL;
+ GNUNET_assert (NULL == crm->qe);
+ LOG (GNUNET_ERROR_TYPE_DEBUG,
+ "Retrying transmission on %s of message %u\n",
+ GCCH_2s (ch),
+ (unsigned int) ntohl (crm->data_message->mid.mid));
+ crm->qe = GCT_send (ch->t,
+ &crm->data_message->header,
+ &data_sent_cb,
+ crm);
+ GNUNET_assert (NULL == ch->retry_data_task);
+}
+
+
+/**
+ * We got an PLAINTEXT_DATA_ACK for a message in our queue, remove it from
+ * the queue and tell our client that it can send more.
+ *
+ * @param ch the channel that got the PLAINTEXT_DATA_ACK
+ * @param cti identifier of the connection that delivered the message
+ * @param crm the message that got acknowledged
+ */
+static void
+handle_matching_ack (struct CadetChannel *ch,
+ const struct GNUNET_CADET_ConnectionTunnelIdentifier *cti,
+ struct CadetReliableMessage *crm)
+{
+ GNUNET_CONTAINER_DLL_remove (ch->head_sent,
+ ch->tail_sent,
+ crm);
+ ch->pending_messages--;
+ GNUNET_assert (ch->pending_messages < ch->max_pending_messages);
+ LOG (GNUNET_ERROR_TYPE_DEBUG,
+ "Received DATA_ACK on %s for message %u (%u ACKs pending)\n",
+ GCCH_2s (ch),
+ (unsigned int) ntohl (crm->data_message->mid.mid),
+ ch->pending_messages);
+ if (NULL != crm->qe)
+ {
+ GCT_send_cancel (crm->qe);
+ crm->qe = NULL;
+ }
+ if ( (1 == crm->num_transmissions) &&
+ (NULL != cti) )
+ {
+ GCC_ack_observed (cti);
+ if (0 == memcmp (cti,
+ &crm->connection_taken,
+ sizeof (struct GNUNET_CADET_ConnectionTunnelIdentifier)))
+ {
+ GCC_latency_observed (cti,
+ GNUNET_TIME_absolute_get_duration (crm->first_transmission_time));
+ }
+ }
+ GNUNET_free (crm->data_message);
+ GNUNET_free (crm);
+ send_ack_to_client (ch,
+ (NULL == ch->owner)
+ ? GNUNET_NO
+ : GNUNET_YES);
}
* Possibly resume transmissions.
*
* @param ch channel that got the ack
+ * @param cti identifier of the connection that delivered the message
* @param ack details about what was received
*/
void
GCCH_handle_channel_plaintext_data_ack (struct CadetChannel *ch,
+ const struct GNUNET_CADET_ConnectionTunnelIdentifier *cti,
const struct GNUNET_CADET_ChannelDataAckMessage *ack)
{
struct CadetReliableMessage *crm;
+ struct CadetReliableMessage *crmn;
+ int found;
+ uint32_t mid_base;
+ uint64_t mid_mask;
+ unsigned int delta;
GNUNET_break (GNUNET_NO == ch->is_loopback);
if (GNUNET_NO == ch->reliable)
GNUNET_break_op (0);
return;
}
+ /* mid_base is the MID of the next message that the
+ other peer expects (i.e. that is missing!), everything
+ LOWER (but excluding mid_base itself) was received. */
+ mid_base = ntohl (ack->mid.mid);
+ mid_mask = GNUNET_htonll (ack->futures);
+ found = GNUNET_NO;
for (crm = ch->head_sent;
NULL != crm;
- crm = crm->next)
- if (ack->mid.mid == crm->data_message->mid.mid)
- break;
- if (NULL == crm)
+ crm = crmn)
+ {
+ crmn = crm->next;
+ delta = (unsigned int) (ntohl (crm->data_message->mid.mid) - mid_base);
+ if (delta >= UINT_MAX - ch->max_pending_messages)
+ {
+ /* overflow, means crm was a bit in the past, so this ACK counts for it. */
+ LOG (GNUNET_ERROR_TYPE_DEBUG,
+ "Got DATA_ACK with base %u satisfying past message %u on %s\n",
+ (unsigned int) mid_base,
+ ntohl (crm->data_message->mid.mid),
+ GCCH_2s (ch));
+ handle_matching_ack (ch,
+ cti,
+ crm);
+ found = GNUNET_YES;
+ continue;
+ }
+ delta--;
+ if (delta >= 64)
+ continue;
+ LOG (GNUNET_ERROR_TYPE_DEBUG,
+ "Testing bit %llX for mid %u (base: %u)\n",
+ (1LLU << delta),
+ ntohl (crm->data_message->mid.mid),
+ mid_base);
+ if (0 != (mid_mask & (1LLU << delta)))
+ {
+ LOG (GNUNET_ERROR_TYPE_DEBUG,
+ "Got DATA_ACK with mask for %u on %s\n",
+ ntohl (crm->data_message->mid.mid),
+ GCCH_2s (ch));
+ handle_matching_ack (ch,
+ cti,
+ crm);
+ found = GNUNET_YES;
+ }
+ }
+ if (GNUNET_NO == found)
{
/* ACK for message we already dropped, might have been a
duplicate ACK? Ignore. */
GNUNET_NO);
return;
}
- GNUNET_CONTAINER_DLL_remove (ch->head_sent,
- ch->tail_sent,
- crm);
- GNUNET_free (crm->data_message);
- GNUNET_free (crm);
- ch->pending_messages--;
- send_ack_to_client (ch,
- (NULL == ch->owner)
- ? GNUNET_NO
- : GNUNET_YES);
- GNUNET_assert (ch->pending_messages < ch->max_pending_messages);
- LOG (GNUNET_ERROR_TYPE_DEBUG,
- "Received DATA_ACK on %s for message %u (%u ACKs pending)\n",
- GCCH_2s (ch),
- (unsigned int) ntohl (ack->mid.mid),
- ch->pending_messages);
- send_ack_to_client (ch,
- (NULL == ch->owner)
- ? GNUNET_NO
- : GNUNET_YES);
+ if (NULL != ch->retry_data_task)
+ {
+ GNUNET_SCHEDULER_cancel (ch->retry_data_task);
+ ch->retry_data_task = NULL;
+ }
+ if ( (NULL != ch->head_sent) &&
+ (NULL == ch->head_sent->qe) )
+ ch->retry_data_task
+ = GNUNET_SCHEDULER_add_at (ch->head_sent->next_retry,
+ &retry_transmission,
+ ch);
}
* the tunnel.
*
* @param ch channel to destroy
+ * @param cti identifier of the connection that delivered the message,
+ * NULL if we are simulating receiving a destroy due to shutdown
*/
void
-GCCH_handle_remote_destroy (struct CadetChannel *ch)
+GCCH_handle_remote_destroy (struct CadetChannel *ch,
+ const struct GNUNET_CADET_ConnectionTunnelIdentifier *cti)
{
struct CadetChannelClient *ccc;
return;
}
ccc = (NULL != ch->owner) ? ch->owner : ch->dest;
- if (NULL != ccc->head_recv)
+ if ( (NULL != ccc) &&
+ (NULL != ccc->head_recv) )
{
LOG (GNUNET_ERROR_TYPE_WARNING,
"Lost end of transmission due to remote shutdown on %s\n",
/* FIXME: change API to notify client about truncated transmission! */
}
ch->destroy = GNUNET_YES;
- GSC_handle_remote_channel_destroy (ccc->c,
- ccc->ccn,
- ch);
+ if (NULL != ccc)
+ GSC_handle_remote_channel_destroy (ccc->c,
+ ccc->ccn,
+ ch);
channel_destroy (ch);
}
/**
- * Function called once the tunnel has sent one of our messages.
- * If the message is unreliable, simply frees the `crm`. If the
- * message was reliable, calculate retransmission time and
- * wait for ACK (or retransmit).
- *
- * @param cls the `struct CadetReliableMessage` that was sent
- */
-static void
-data_sent_cb (void *cls);
-
-
-/**
- * We need to retry a transmission, the last one took too long to
- * be acknowledged.
+ * Test if element @a e1 comes before element @a e2.
*
- * @param cls the `struct CadetChannel` where we need to retransmit
+ * @param cls closure, to a flag where we indicate duplicate packets
+ * @param crm1 an element of to sort
+ * @param crm2 another element to sort
+ * @return #GNUNET_YES if @e1 < @e2, otherwise #GNUNET_NO
*/
-static void
-retry_transmission (void *cls)
+static int
+cmp_crm_by_next_retry (void *cls,
+ struct CadetReliableMessage *crm1,
+ struct CadetReliableMessage *crm2)
{
- struct CadetChannel *ch = cls;
- struct CadetReliableMessage *crm = ch->head_sent;
-
- ch->retry_data_task = NULL;
- GNUNET_assert (NULL == crm->qe);
- crm->qe = GCT_send (ch->t,
- &crm->data_message->header,
- &data_sent_cb,
- crm);
+ if (crm1->next_retry.abs_value_us <
+ crm2->next_retry.abs_value_us)
+ return GNUNET_YES;
+ return GNUNET_NO;
}
* wait for ACK (or retransmit).
*
* @param cls the `struct CadetReliableMessage` that was sent
+ * @param cid identifier of the connection within the tunnel, NULL
+ * if transmission failed
*/
static void
-data_sent_cb (void *cls)
+data_sent_cb (void *cls,
+ const struct GNUNET_CADET_ConnectionTunnelIdentifier *cid)
{
struct CadetReliableMessage *crm = cls;
struct CadetChannel *ch = crm->ch;
- struct CadetReliableMessage *off;
GNUNET_assert (GNUNET_NO == ch->is_loopback);
+ GNUNET_assert (NULL != crm->qe);
crm->qe = NULL;
GNUNET_CONTAINER_DLL_remove (ch->head_sent,
ch->tail_sent,
crm);
if (GNUNET_NO == ch->reliable)
{
+ GNUNET_free (crm->data_message);
GNUNET_free (crm);
ch->pending_messages--;
send_ack_to_client (ch,
: GNUNET_YES);
return;
}
- if (0 == crm->retry_delay.rel_value_us)
- crm->retry_delay = ch->expected_delay;
- crm->next_retry = GNUNET_TIME_relative_to_absolute (crm->retry_delay);
-
- /* find position for re-insertion into the DLL */
- if ( (NULL == ch->head_sent) ||
- (crm->next_retry.abs_value_us < ch->head_sent->next_retry.abs_value_us) )
+ if (NULL == cid)
{
- /* insert at HEAD, also (re)schedule retry task! */
- GNUNET_CONTAINER_DLL_insert (ch->head_sent,
- ch->tail_sent,
- crm);
- if (NULL != ch->retry_data_task)
- GNUNET_SCHEDULER_cancel (ch->retry_data_task);
- ch->retry_data_task
- = GNUNET_SCHEDULER_add_delayed (crm->retry_delay,
- &retry_transmission,
- ch);
- return;
+ /* There was an error sending. */
+ crm->num_transmissions = GNUNET_SYSERR;
}
- for (off = ch->head_sent; NULL != off; off = off->next)
- if (crm->next_retry.abs_value_us < off->next_retry.abs_value_us)
- break;
- if (NULL == off)
+ else if (GNUNET_SYSERR != crm->num_transmissions)
{
- /* insert at tail */
- GNUNET_CONTAINER_DLL_insert_tail (ch->head_sent,
+ /* Increment transmission counter, and possibly store @a cid
+ if this was the first transmission. */
+ crm->num_transmissions++;
+ if (1 == crm->num_transmissions)
+ {
+ crm->first_transmission_time = GNUNET_TIME_absolute_get ();
+ crm->connection_taken = *cid;
+ GCC_ack_expected (cid);
+ }
+ }
+ if ( (0 == crm->retry_delay.rel_value_us) &&
+ (NULL != cid) )
+ {
+ struct CadetConnection *cc = GCC_lookup (cid);
+
+ if (NULL != cc)
+ crm->retry_delay = GCC_get_metrics (cc)->aged_latency;
+ else
+ crm->retry_delay = ch->retry_time;
+ }
+ crm->retry_delay = GNUNET_TIME_STD_BACKOFF (crm->retry_delay);
+ crm->retry_delay = GNUNET_TIME_relative_max (crm->retry_delay,
+ MIN_RTT_DELAY);
+ crm->next_retry = GNUNET_TIME_relative_to_absolute (crm->retry_delay);
+
+ GNUNET_CONTAINER_DLL_insert_sorted (struct CadetReliableMessage,
+ cmp_crm_by_next_retry,
+ NULL,
+ ch->head_sent,
ch->tail_sent,
crm);
- }
- else
+ LOG (GNUNET_ERROR_TYPE_DEBUG,
+ "Message %u sent, next transmission on %s in %s\n",
+ (unsigned int) ntohl (crm->data_message->mid.mid),
+ GCCH_2s (ch),
+ GNUNET_STRINGS_relative_time_to_string (GNUNET_TIME_absolute_get_remaining (ch->head_sent->next_retry),
+ GNUNET_YES));
+ if (NULL == ch->head_sent->qe)
{
- /* insert before off */
- GNUNET_CONTAINER_DLL_insert_after (ch->head_sent,
- ch->tail_sent,
- off->prev,
- crm);
+ if (NULL != ch->retry_data_task)
+ GNUNET_SCHEDULER_cancel (ch->retry_data_task);
+ ch->retry_data_task
+ = GNUNET_SCHEDULER_add_at (ch->head_sent->next_retry,
+ &retry_transmission,
+ ch);
}
}
GNUNET_break (0);
return GNUNET_SYSERR;
}
+ if (GNUNET_YES == ch->destroy)
+ {
+ /* we are going down, drop messages */
+ return GNUNET_OK;
+ }
ch->pending_messages++;
if (GNUNET_YES == ch->is_loopback)
struct CadetChannelClient *receiver;
struct GNUNET_MQ_Envelope *env;
struct GNUNET_CADET_LocalData *ld;
- int to_owner;
+ int ack_to_owner;
env = GNUNET_MQ_msg_extra (ld,
buf_len,
GNUNET_MESSAGE_TYPE_CADET_LOCAL_DATA);
- if (sender_ccn.channel_of_client ==
- ch->owner->ccn.channel_of_client)
+ if ( (NULL != ch->owner) &&
+ (sender_ccn.channel_of_client ==
+ ch->owner->ccn.channel_of_client) )
{
receiver = ch->dest;
- to_owner = GNUNET_NO;
+ ack_to_owner = GNUNET_YES;
}
- else
+ else if ( (NULL != ch->dest) &&
+ (sender_ccn.channel_of_client ==
+ ch->dest->ccn.channel_of_client) )
{
- GNUNET_assert (sender_ccn.channel_of_client ==
- ch->dest->ccn.channel_of_client);
receiver = ch->owner;
- to_owner = GNUNET_YES;
+ ack_to_owner = GNUNET_NO;
+ }
+ else
+ {
+ GNUNET_break (0);
+ return GNUNET_SYSERR;
}
ld->ccn = receiver->ccn;
GNUNET_memcpy (&ld[1],
buf,
buf_len);
- /* FIXME: this does not provide for flow control! */
- GSC_send_to_client (receiver->c,
- env);
- send_ack_to_client (ch,
- to_owner);
+ if (GNUNET_YES == receiver->client_ready)
+ {
+ ch->pending_messages--;
+ GSC_send_to_client (receiver->c,
+ env);
+ send_ack_to_client (ch,
+ ack_to_owner);
+ }
+ else
+ {
+ struct CadetOutOfOrderMessage *oom;
+
+ oom = GNUNET_new (struct CadetOutOfOrderMessage);
+ oom->env = env;
+ GNUNET_CONTAINER_DLL_insert_tail (receiver->head_recv,
+ receiver->tail_recv,
+ oom);
+ receiver->num_recv++;
+ }
return GNUNET_OK;
}
GNUNET_memcpy (&crm->data_message[1],
buf,
buf_len);
- GNUNET_CONTAINER_DLL_insert (ch->head_sent,
- ch->tail_sent,
- crm);
+ GNUNET_CONTAINER_DLL_insert_tail (ch->head_sent,
+ ch->tail_sent,
+ crm);
LOG (GNUNET_ERROR_TYPE_DEBUG,
- "Sending %u bytes from local client to %s\n",
- buf_len,
- GCCH_2s (ch));
+ "Sending message %u from local client to %s with %u bytes\n",
+ ntohl (crm->data_message->mid.mid),
+ GCCH_2s (ch),
+ buf_len);
+ if (NULL != ch->retry_data_task)
+ {
+ GNUNET_SCHEDULER_cancel (ch->retry_data_task);
+ ch->retry_data_task = NULL;
+ }
crm->qe = GCT_send (ch->t,
&crm->data_message->header,
&data_sent_cb,
crm);
+ GNUNET_assert (NULL == ch->retry_data_task);
return GNUNET_OK;
}
else
GNUNET_assert (0);
ccc->client_ready = GNUNET_YES;
- LOG (GNUNET_ERROR_TYPE_DEBUG,
- "Got LOCAL_ACK, client ready to receive more data!\n");
com = ccc->head_recv;
if (NULL == com)
+ {
+ LOG (GNUNET_ERROR_TYPE_DEBUG,
+ "Got LOCAL_ACK, %s-%X ready to receive more data, but none pending on %s-%X(%p)!\n",
+ GSC_2s (ccc->c),
+ ntohl (client_ccn.channel_of_client),
+ GCCH_2s (ch),
+ ntohl (ccc->ccn.channel_of_client),
+ ccc);
return; /* none pending */
+ }
+ if (GNUNET_YES == ch->is_loopback)
+ {
+ int to_owner;
+
+ /* Messages are always in-order, just send */
+ GNUNET_CONTAINER_DLL_remove (ccc->head_recv,
+ ccc->tail_recv,
+ com);
+ ccc->num_recv--;
+ GSC_send_to_client (ccc->c,
+ com->env);
+ /* Notify sender that we can receive more */
+ if (ccc->ccn.channel_of_client ==
+ ch->owner->ccn.channel_of_client)
+ {
+ to_owner = GNUNET_NO;
+ }
+ else
+ {
+ GNUNET_assert (ccc->ccn.channel_of_client ==
+ ch->dest->ccn.channel_of_client);
+ to_owner = GNUNET_YES;
+ }
+ send_ack_to_client (ch,
+ to_owner);
+ GNUNET_free (com);
+ return;
+ }
+
if ( (com->mid.mid != ch->mid_recv.mid) &&
- (GNUNET_NO == ch->out_of_order) )
+ (GNUNET_NO == ch->out_of_order) &&
+ (GNUNET_YES == ch->reliable) )
+ {
+ LOG (GNUNET_ERROR_TYPE_DEBUG,
+ "Got LOCAL_ACK, %s-%X ready to receive more data (but next one is out-of-order %u vs. %u)!\n",
+ GSC_2s (ccc->c),
+ ntohl (ccc->ccn.channel_of_client),
+ ntohl (com->mid.mid),
+ ntohl (ch->mid_recv.mid));
return; /* missing next one in-order */
+ }
- GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
- "Passing payload message to client on %s\n",
- GCCH_2s (ch));
+ LOG (GNUNET_ERROR_TYPE_DEBUG,
+ "Got LOCAL_ACK, giving payload message %u to %s-%X on %s\n",
+ ntohl (com->mid.mid),
+ GSC_2s (ccc->c),
+ ntohl (ccc->ccn.channel_of_client),
+ GCCH_2s (ch));
/* all good, pass next message to client */
GNUNET_CONTAINER_DLL_remove (ccc->head_recv,
ccc->tail_recv,
com);
+ ccc->num_recv--;
/* FIXME: if unreliable, this is not aggressive
enough, as it would be OK to have lost some! */
+
ch->mid_recv.mid = htonl (1 + ntohl (com->mid.mid));
ch->mid_futures >>= 1; /* equivalent to division by 2 */
ccc->client_ready = GNUNET_NO;
GSC_send_to_client (ccc->c,
com->env);
GNUNET_free (com);
- if ( (0xFFULL == (ch->mid_futures & 0xFFULL)) &&
- (GNUNET_YES == ch->reliable) )
- {
- /* The next 15 messages were also already received (0xFF), this
- suggests that the sender may be blocked on flow control
- urgently waiting for an ACK from us. (As we have an inherent
- maximum of 64 bits, and 15 is getting too close for comfort.)
- So we should send one now. */
- GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
- "Sender on %s likely blocked on flow-control, sending ACK now.\n",
- GCCH_2s (ch));
- if (GNUNET_YES == ch->reliable)
- send_channel_data_ack (ch);
- }
-
+ send_channel_data_ack (ch);
if (NULL != ccc->head_recv)
return;
if (GNUNET_NO == ch->destroy)
projects / oweals / gnunet.git / blobdiff