gnunet-service-cadet_channel.c File Reference

logical links between CADET clients More...

#include "gnunet_common.h"
#include "platform.h"
#include "cadet.h"
#include "gnunet_statistics_service.h"
#include "gnunet-service-cadet_channel.h"
#include "gnunet-service-cadet_connection.h"
#include "gnunet-service-cadet_tunnels.h"
#include "gnunet-service-cadet_paths.h"

Include dependency graph for gnunet-service-cadet_channel.c:

Go to the source code of this file.

Data Structures
struct	CadetReliableMessage
	Info needed to retry a message in case it gets lost. More...
struct	CadetOutOfOrderMessage
	List of received out-of-order data messages. More...
struct	CadetChannelClient
	Client endpoint of a struct CadetChannel. More...
struct	CadetChannel
	Struct containing all information regarding a channel to a remote client. More...

Macros
#define	LOG(level, ...)   GNUNET_log_from (level, "cadet-chn", __VA_ARGS__)
#define	CADET_INITIAL_RETRANSMIT_TIME    GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_MILLISECONDS, 250)
	How long do we initially wait before retransmitting?
#define	TIMEOUT_CLOSED_PORT    GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_SECONDS, 30)
	How long do we wait before dropping state about incoming connection to closed port?
#define	MIN_RTT_DELAY    GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_MILLISECONDS, 75)
	How long do we wait at least before retransmitting ever?
#define	MAX_OUT_OF_ORDER_DISTANCE   1024
	Maximum message ID into the future we accept for out-of-order messages.
#define	LOG2(level, ...)    GNUNET_log_from_nocheck (level, "cadet-chn", __VA_ARGS__)

Enumerations
enum	CadetChannelState { CADET_CHANNEL_NEW , CADET_CHANNEL_LOOSE , CADET_CHANNEL_OPEN_SENT , CADET_CHANNEL_READY }
	All the states a channel can be in. More...

Functions
void	GCCH_assign_type_to_drop (struct CadetChannel *ch, const struct GNUNET_CADET_RequestDropCadetMessage *message)
	Assign type of message to drop.
int	GCCH_is_type_to_drop (struct CadetChannel *ch, const struct GNUNET_MessageHeader *message)
	Check if type of message is the one to drop.
const char *	GCCH_2s (const struct CadetChannel *ch)
	Get the static string for identification of the channel.
void	GCCH_hash_port (struct GNUNET_HashCode *h_port, const struct GNUNET_HashCode *port, const struct GNUNET_PeerIdentity *listener)
	Hash the port and initiator and listener to calculate the "challenge" h_port we send to the other peer on GNUNET_MESSAGE_TYPE_CADET_CHANNEL_OPEN.
struct GNUNET_CADET_ChannelTunnelNumber	GCCH_get_id (const struct CadetChannel *ch)
	Get the channel's public ID.
static void	free_channel_client (struct CadetChannelClient *ccc)
	Release memory associated with ccc.
static void	channel_destroy (struct CadetChannel *ch)
	Destroy the given channel.
static void	send_channel_open (void *cls)
	Send a channel create message.
static void	channel_open_sent_cb (void *cls, const struct GNUNET_CADET_ConnectionTunnelIdentifier *cid)
	Function called once the tunnel confirms that we sent the create message.
void	GCCH_tunnel_up (struct CadetChannel *ch)
	Function called once and only once after a channel was bound to its tunnel via GCT_add_channel() is ready for transmission.
struct CadetChannel *	GCCH_channel_local_new (struct CadetClient *owner, struct GNUNET_CADET_ClientChannelNumber ccn, struct CadetPeer *destination, const struct GNUNET_HashCode *port, uint32_t options)
	Create a new channel.
static void	timeout_closed_cb (void *cls)
	We had an incoming channel to a port that is closed.
struct CadetChannel *	GCCH_channel_incoming_new (struct CadetTunnel *t, struct GNUNET_CADET_ChannelTunnelNumber ctn, const struct GNUNET_HashCode *h_port, uint32_t options)
	Create a new channel based on a request coming in over the network.
static void	send_ack_cb (void *cls, const struct GNUNET_CADET_ConnectionTunnelIdentifier *cid)
	Function called once the tunnel confirms that we sent the ACK message.
static void	send_channel_data_ack (struct CadetChannel *ch)
	Compute and send the current GNUNET_MESSAGE_TYPE_CADET_CHANNEL_APP_DATA_ACK to the other peer.
static void	send_open_ack (void *cls)
	Send our initial GNUNET_MESSAGE_TYPE_CADET_CHANNEL_OPEN_ACK to the client confirming that the connection is up.
void	GCCH_handle_duplicate_open (struct CadetChannel *ch, const struct GNUNET_CADET_ConnectionTunnelIdentifier *cti)
	We got a GNUNET_MESSAGE_TYPE_CADET_CHANNEL_OPEN message again for this channel.
static void	send_ack_to_client (struct CadetChannel *ch, int to_owner)
	Send a GNUNET_MESSAGE_TYPE_CADET_LOCAL_ACK to the client to solicit more messages.
void	GCCH_bind (struct CadetChannel *ch, struct CadetClient *c, const struct GNUNET_HashCode *port)
	A client is bound to the port that we have a channel open to.
static void	signal_remote_destroy_cb (void *cls)
	One of our clients has disconnected, tell the other one that we are finished.
void	GCCH_channel_local_destroy (struct CadetChannel *ch, struct CadetClient *c, struct GNUNET_CADET_ClientChannelNumber ccn)
	Destroy locally created channel.
void	GCCH_handle_channel_open_ack (struct CadetChannel *ch, const struct GNUNET_CADET_ConnectionTunnelIdentifier *cti, const struct GNUNET_HashCode *port)
	We got an acknowledgement for the creation of the channel (the port is open on the other side).
static int	is_before (void *cls, struct CadetOutOfOrderMessage *m1, struct CadetOutOfOrderMessage *m2)
	Test if element e1 comes before element e2.
void	GCCH_handle_channel_plaintext_data (struct CadetChannel *ch, const struct GNUNET_CADET_ConnectionTunnelIdentifier *cti, const struct GNUNET_CADET_ChannelAppDataMessage *msg)
	We got payload data for a channel.
static void	data_sent_cb (void *cls, const struct GNUNET_CADET_ConnectionTunnelIdentifier *cid)
	Function called once the tunnel has sent one of our messages.
static void	retry_transmission (void *cls)
	We need to retry a transmission, the last one took too long to be acknowledged.
static void	handle_matching_ack (struct CadetChannel *ch, const struct GNUNET_CADET_ConnectionTunnelIdentifier *cti, struct CadetReliableMessage *crm)
	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.
void	GCCH_handle_channel_plaintext_data_ack (struct CadetChannel *ch, const struct GNUNET_CADET_ConnectionTunnelIdentifier *cti, const struct GNUNET_CADET_ChannelDataAckMessage *ack)
	We got an acknowledgement for payload data for a channel.
void	GCCH_handle_remote_destroy (struct CadetChannel *ch, const struct GNUNET_CADET_ConnectionTunnelIdentifier *cti)
	Destroy channel, based on the other peer closing the connection.
static int	cmp_crm_by_next_retry (void *cls, struct CadetReliableMessage *crm1, struct CadetReliableMessage *crm2)
	Test if element e1 comes before element e2.
int	GCCH_handle_local_data (struct CadetChannel *ch, struct GNUNET_CADET_ClientChannelNumber sender_ccn, const char *buf, size_t buf_len)
	Handle data given by a client.
void	GCCH_handle_local_ack (struct CadetChannel *ch, struct GNUNET_CADET_ClientChannelNumber client_ccn)
	Handle ACK from client on local channel.
void	GCCH_debug (struct CadetChannel *ch, enum GNUNET_ErrorType level)
	Log channel info.

Detailed Description

logical links between CADET clients

Author

Bartlomiej Polot

Christian Grothoff

TODO:

• 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?

Definition in file gnunet-service-cadet_channel.c.

Macro Definition Documentation

LOG

#define LOG	(		level,
			...
	)		GNUNET_log_from (level, "cadet-chn", __VA_ARGS__)

Definition at line 45 of file gnunet-service-cadet_channel.c.

CADET_INITIAL_RETRANSMIT_TIME

#define CADET_INITIAL_RETRANSMIT_TIME    GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_MILLISECONDS, 250)

How long do we initially wait before retransmitting?

Definition at line 50 of file gnunet-service-cadet_channel.c.

{
  CADET_CHANNEL_NEW,
 
  CADET_CHANNEL_LOOSE,
 
  CADET_CHANNEL_OPEN_SENT,
 
  CADET_CHANNEL_READY
};
 
 
struct CadetReliableMessage
{
  struct CadetReliableMessage *next;
 
  struct CadetReliableMessage *prev;
 
  struct CadetChannel *ch;
 
  struct CadetTunnelQueueEntry *qe;
 
  struct GNUNET_CADET_ChannelAppDataMessage *data_message;
 
  struct GNUNET_TIME_Absolute next_retry;
 
  struct GNUNET_TIME_Relative retry_delay;
 
  struct GNUNET_TIME_Absolute first_transmission_time;
 
  struct GNUNET_CADET_ConnectionTunnelIdentifier connection_taken;
 
  int num_transmissions;
};
 
 
struct CadetOutOfOrderMessage
{
  struct CadetOutOfOrderMessage *next;
 
  struct CadetOutOfOrderMessage *prev;
 
  struct ChannelMessageIdentifier mid;
 
  struct GNUNET_MQ_Envelope *env;
};
 
 
struct CadetChannelClient
{
  struct CadetClient *c;
 
  struct CadetOutOfOrderMessage *head_recv;
 
  struct CadetOutOfOrderMessage *tail_recv;
 
  struct GNUNET_CADET_ClientChannelNumber ccn;
 
  unsigned int num_recv;
 
  int client_ready;
};
 
 
struct CadetChannel
{
  struct CadetTunnel *t;
 
  struct CadetChannelClient *owner;
 
  struct CadetChannelClient *dest;
 
  struct CadetTunnelQueueEntry *last_control_qe;
 
  struct CadetReliableMessage *head_sent;
 
  struct CadetReliableMessage *tail_sent;
 
  struct GNUNET_SCHEDULER_Task *retry_control_task;
 
  struct GNUNET_SCHEDULER_Task *retry_data_task;
 
  struct GNUNET_TIME_Absolute timestamp;
 
  struct GNUNET_HashCode port;
 
  struct GNUNET_HashCode h_port;
 
  struct GNUNET_TIME_Relative retry_time;
 
  uint64_t mid_futures;
 
  struct ChannelMessageIdentifier mid_recv;
 
  struct ChannelMessageIdentifier mid_send;
 
  unsigned int pending_messages;
 
  unsigned int max_pending_messages;
 
  struct GNUNET_CADET_ChannelTunnelNumber ctn;
 
  enum CadetChannelState state;
 
  unsigned int skip_ack_series;
 
  int nobuffer;
 
  int reliable;
 
  int out_of_order;
 
  int is_loopback;
 
  int destroy;
 
  uint16_t type GNUNET_PACKED;
 
};
 
void
GCCH_assign_type_to_drop (struct CadetChannel *ch, const struct
                          GNUNET_CADET_RequestDropCadetMessage *message)
{
 
  ch->type = message->type;
 
}
 
 
int
GCCH_is_type_to_drop (struct CadetChannel *ch, const struct
                      GNUNET_MessageHeader *message)
{
 
  if (ch->type == message->type)
  {
    ch->type = 0;
    return GNUNET_YES;
  }
  else
    return GNUNET_NO;
}
 
 
const char *
GCCH_2s (const struct CadetChannel *ch)
{
  static char buf[128];
 
  GNUNET_snprintf (buf,
                   sizeof(buf),
                   "Channel %s:%s ctn:%X(%X/%X)",
                   (GNUNET_YES == ch->is_loopback)
                   ? "loopback"
                   : GNUNET_i2s (GCP_get_id (GCT_get_destination (ch->t))),
                   GNUNET_h2s (&ch->port),
                   ch->ctn.cn,
                   (NULL == ch->owner)
                   ? 0
                   : ntohl (ch->owner->ccn.channel_of_client),
                   (NULL == ch->dest)
                   ? 0
                   : ntohl (ch->dest->ccn.channel_of_client));
  return buf;
}
 
 
void
GCCH_hash_port (struct GNUNET_HashCode *h_port,
                const struct GNUNET_HashCode *port,
                const struct GNUNET_PeerIdentity *listener)
{
  struct GNUNET_HashContext *hc;
 
  hc = GNUNET_CRYPTO_hash_context_start ();
  GNUNET_CRYPTO_hash_context_read (hc, port, sizeof(*port));
  GNUNET_CRYPTO_hash_context_read (hc, listener, sizeof(*listener));
  GNUNET_CRYPTO_hash_context_finish (hc, h_port);
  LOG (GNUNET_ERROR_TYPE_DEBUG,
       "Calculated port hash %s\n",
       GNUNET_h2s (h_port));
}
 
 
struct GNUNET_CADET_ChannelTunnelNumber
GCCH_get_id (const struct CadetChannel *ch)
{
  return ch->ctn;
}
 
 
static void
free_channel_client (struct CadetChannelClient *ccc)
{
  struct CadetOutOfOrderMessage *com;
 
  while (NULL != (com = ccc->head_recv))
  {
    GNUNET_CONTAINER_DLL_remove (ccc->head_recv, ccc->tail_recv, com);
    ccc->num_recv--;
    GNUNET_MQ_discard (com->env);
    GNUNET_free (com);
  }
  GNUNET_free (ccc);
}
 
 
static void
channel_destroy (struct CadetChannel *ch)
{
  struct CadetReliableMessage *crm;
 
  while (NULL != (crm = ch->head_sent))
  {
    GNUNET_assert (ch == crm->ch);
    if (NULL != crm->qe)
    {
      GCT_send_cancel (crm->qe);
      crm->qe = NULL;
    }
    GNUNET_CONTAINER_DLL_remove (ch->head_sent, ch->tail_sent, crm);
    GNUNET_free (crm->data_message);
    GNUNET_free (crm);
  }
  if (CADET_CHANNEL_LOOSE == ch->state)
  {
    GSC_drop_loose_channel (&ch->h_port, ch);
  }
  if (NULL != ch->owner)
  {
    free_channel_client (ch->owner);
    ch->owner = NULL;
  }
  if (NULL != ch->dest)
  {
    free_channel_client (ch->dest);
    ch->dest = NULL;
  }
  if (NULL != ch->last_control_qe)
  {
    GCT_send_cancel (ch->last_control_qe);
    ch->last_control_qe = NULL;
  }
  if (NULL != ch->retry_data_task)
  {
    GNUNET_SCHEDULER_cancel (ch->retry_data_task);
    ch->retry_data_task = NULL;
  }
  if (NULL != ch->retry_control_task)
  {
    GNUNET_SCHEDULER_cancel (ch->retry_control_task);
    ch->retry_control_task = NULL;
  }
  if (GNUNET_NO == ch->is_loopback)
  {
    GCT_remove_channel (ch->t, ch, ch->ctn);
    ch->t = NULL;
  }
  GNUNET_free (ch);
}
 
 
static void
send_channel_open (void *cls);
 
 
static void
channel_open_sent_cb (void *cls,
                      const struct GNUNET_CADET_ConnectionTunnelIdentifier *cid)
{
  struct CadetChannel *ch = cls;
 
  GNUNET_assert (NULL != ch->last_control_qe);
  ch->last_control_qe = NULL;
  ch->retry_time = GNUNET_TIME_STD_BACKOFF (ch->retry_time);
  LOG (GNUNET_ERROR_TYPE_DEBUG,
       "Sent CADET_CHANNEL_OPEN on %s, retrying in %s\n",
       GCCH_2s (ch),
       GNUNET_STRINGS_relative_time_to_string (ch->retry_time, GNUNET_YES));
  ch->retry_control_task =
    GNUNET_SCHEDULER_add_delayed (ch->retry_time, &send_channel_open, ch);
}
 
 
static void
send_channel_open (void *cls)
{
  struct CadetChannel *ch = cls;
  struct GNUNET_CADET_ChannelOpenMessage msgcc;
 
  ch->retry_control_task = NULL;
  LOG (GNUNET_ERROR_TYPE_DEBUG,
       "Sending CHANNEL_OPEN message for %s\n",
       GCCH_2s (ch));
  msgcc.header.size = htons (sizeof(msgcc));
  msgcc.header.type = htons (GNUNET_MESSAGE_TYPE_CADET_CHANNEL_OPEN);
  // TODO This will be removed in a major release, because this will be a protocol breaking change. We set the deprecated "reliable" bit here that was removed.
  msgcc.opt = 2;
  msgcc.h_port = ch->h_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, &msgcc.ctn);
  GNUNET_assert (NULL == ch->retry_control_task);
}
 
 
void
GCCH_tunnel_up (struct CadetChannel *ch)
{
  GNUNET_assert (NULL == ch->retry_control_task);
  LOG (GNUNET_ERROR_TYPE_DEBUG,
       "Tunnel up, sending CHANNEL_OPEN on %s now\n",
       GCCH_2s (ch));
  ch->retry_control_task = GNUNET_SCHEDULER_add_now (&send_channel_open, ch);
}
 
 
struct CadetChannel *
GCCH_channel_local_new (struct CadetClient *owner,
                        struct GNUNET_CADET_ClientChannelNumber ccn,
                        struct CadetPeer *destination,
                        const struct GNUNET_HashCode *port,
                        uint32_t options)
{
  const struct GNUNET_PeerIdentity *my_identity;
  struct CadetChannel *ch;
  struct CadetChannelClient *ccco;
 
  my_identity = GNUNET_PILS_get_identity (pils);
  GNUNET_assert (my_identity);
 
  ccco = GNUNET_new (struct CadetChannelClient);
  ccco->c = owner;
  ccco->ccn = ccn;
  ccco->client_ready = GNUNET_YES;
 
  ch = GNUNET_new (struct CadetChannel);
  ch->mid_recv.mid = htonl (1);  /* The OPEN_ACK counts as message 0! */
  ch->nobuffer = GNUNET_NO;
  ch->reliable = GNUNET_YES;
  ch->out_of_order = GNUNET_NO;
  ch->max_pending_messages =
    (ch->nobuffer) ? 1 : 4; /* FIXME: 4!? Do not hardcode! */
  ch->owner = ccco;
  ch->port = *port;
  GCCH_hash_port (&ch->h_port, port, GCP_get_id (destination));
  if (0 == GNUNET_memcmp (my_identity, GCP_get_id (destination)))
  {
    struct OpenPort *op;
 
    ch->is_loopback = GNUNET_YES;
    op = GNUNET_CONTAINER_multihashmap_get (open_ports, &ch->h_port);
    if (NULL == op)
    {
      /* port closed, wait for it to possibly open */
      ch->state = CADET_CHANNEL_LOOSE;
      (void) GNUNET_CONTAINER_multihashmap_put (
        loose_channels,
        &ch->h_port,
        ch,
        GNUNET_CONTAINER_MULTIHASHMAPOPTION_MULTIPLE);
      LOG (GNUNET_ERROR_TYPE_DEBUG,
           "Created loose incoming loopback channel to port %s\n",
           GNUNET_h2s (&ch->port));
    }
    else
    {
      GCCH_bind (ch, op->c, &op->port);
    }
  }
  else
  {
    ch->t = GCP_get_tunnel (destination, GNUNET_YES);
    ch->retry_time = CADET_INITIAL_RETRANSMIT_TIME;
    ch->ctn = GCT_add_channel (ch->t, ch);
  }
  GNUNET_STATISTICS_update (stats, "# channels", 1, GNUNET_NO);
  LOG (GNUNET_ERROR_TYPE_DEBUG,
       "Created channel to port %s at peer %s for %s using %s\n",
       GNUNET_h2s (port),
       GCP_2s (destination),
       GSC_2s (owner),
       (GNUNET_YES == ch->is_loopback) ? "loopback" : GCT_2s (ch->t));
  return ch;
}
 
 
static void
timeout_closed_cb (void *cls)
{
  struct CadetChannel *ch = cls;
 
  ch->retry_control_task = NULL;
  LOG (GNUNET_ERROR_TYPE_DEBUG,
       "Closing incoming channel to port %s from peer %s due to timeout\n",
       GNUNET_h2s (&ch->port),
       GCP_2s (GCT_get_destination (ch->t)));
  channel_destroy (ch);
}
 
 
struct CadetChannel *
GCCH_channel_incoming_new (struct CadetTunnel *t,
                           struct GNUNET_CADET_ChannelTunnelNumber ctn,
                           const struct GNUNET_HashCode *h_port,
                           uint32_t options)
{
  struct CadetChannel *ch;
  struct OpenPort *op;
 
  ch = GNUNET_new (struct CadetChannel);
  ch->h_port = *h_port;
  ch->t = t;
  ch->ctn = ctn;
  ch->retry_time = CADET_INITIAL_RETRANSMIT_TIME;
  ch->nobuffer = GNUNET_NO;
  ch->reliable = GNUNET_YES;
  ch->out_of_order = GNUNET_NO;
  ch->max_pending_messages =
    (ch->nobuffer) ? 1 : 4; /* FIXME: 4!? Do not hardcode! */
  GNUNET_STATISTICS_update (stats, "# channels", 1, GNUNET_NO);
 
  op = GNUNET_CONTAINER_multihashmap_get (open_ports, h_port);
  if (NULL == op)
  {
    /* port closed, wait for it to possibly open */
    ch->state = CADET_CHANNEL_LOOSE;
    (void) GNUNET_CONTAINER_multihashmap_put (
      loose_channels,
      &ch->h_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,
                                                           ch);
    LOG (GNUNET_ERROR_TYPE_DEBUG,
         "Created loose incoming channel to port %s from peer %s\n",
         GNUNET_h2s (&ch->port),
         GCP_2s (GCT_get_destination (ch->t)));
  }
  else
  {
    GCCH_bind (ch, op->c, &op->port);
  }
  GNUNET_STATISTICS_update (stats, "# channels", 1, GNUNET_NO);
  return ch;
}
 
 
static void
send_ack_cb (void *cls,
             const struct GNUNET_CADET_ConnectionTunnelIdentifier *cid)
{
  struct CadetChannel *ch = cls;
 
  GNUNET_assert (NULL != ch->last_control_qe);
  ch->last_control_qe = NULL;
}
 
 
static void
send_channel_data_ack (struct CadetChannel *ch)
{
  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));
  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, &msg.header, &send_ack_cb, ch,
                                  &msg.ctn);
}
 
 
static void
send_open_ack (void *cls)
{
  struct CadetChannel *ch = cls;
  struct GNUNET_CADET_ChannelOpenAckMessage msg;
 
  ch->retry_control_task = NULL;
  LOG (GNUNET_ERROR_TYPE_DEBUG,
       "Sending CHANNEL_OPEN_ACK on %s\n",
       GCCH_2s (ch));
  msg.header.type = htons (GNUNET_MESSAGE_TYPE_CADET_CHANNEL_OPEN_ACK);
  msg.header.size = htons (sizeof(msg));
  msg.reserved = htonl (0);
  msg.ctn = ch->ctn;
  msg.port = ch->port;
  if (NULL != ch->last_control_qe)
    GCT_send_cancel (ch->last_control_qe);
  ch->last_control_qe = GCT_send (ch->t, &msg.header, &send_ack_cb, ch,
                                  &msg.ctn);
}
 
 
void
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",
         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",
         GCCH_2s (ch));
    return;
  }
  LOG (GNUNET_ERROR_TYPE_DEBUG,
       "Retransmitting CHANNEL_OPEN_ACK on %s\n",
       GCCH_2s (ch));
  ch->retry_control_task = GNUNET_SCHEDULER_add_now (&send_open_ack, ch);
}
 
 
static void
send_ack_to_client (struct CadetChannel *ch, int to_owner)
{
  struct GNUNET_MQ_Envelope *env;
  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);
  ack->ccn = ccc->ccn;
  LOG (GNUNET_ERROR_TYPE_DEBUG,
       "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),
       ch->pending_messages,
       ch->max_pending_messages);
  GSC_send_to_client (ccc->c, env);
}
 
 
void
GCCH_bind (struct CadetChannel *ch,
           struct CadetClient *c,
           const struct GNUNET_HashCode *port)
{
  const struct GNUNET_PeerIdentity *my_identity;
  uint32_t options;
  struct CadetChannelClient *cccd;
 
  LOG (GNUNET_ERROR_TYPE_DEBUG,
       "Binding %s from %s to port %s of %s\n",
       GCCH_2s (ch),
       GCT_2s (ch->t),
       GNUNET_h2s (&ch->port),
       GSC_2s (c));
 
  my_identity = GNUNET_PILS_get_identity (pils);
  GNUNET_assert (my_identity);
 
  if (NULL != ch->retry_control_task)
  {
    /* there might be a timeout task here */
    GNUNET_SCHEDULER_cancel (ch->retry_control_task);
    ch->retry_control_task = NULL;
  }
  options = 0;
  cccd = GNUNET_new (struct CadetChannelClient);
  GNUNET_assert (NULL == ch->dest);
  ch->dest = cccd;
  ch->port = *port;
  cccd->c = c;
  cccd->client_ready = GNUNET_YES;
  cccd->ccn = GSC_bind (c,
                        ch,
                        (GNUNET_YES == ch->is_loopback)
                        ? GCP_get (my_identity, GNUNET_YES)
                        : GCT_get_destination (ch->t),
                        port,
                        options);
  GNUNET_assert (ntohl (cccd->ccn.channel_of_client) <
                 GNUNET_CADET_LOCAL_CHANNEL_ID_CLI);
  ch->mid_recv.mid = htonl (1);  /* The OPEN counts as message 0! */
  if (GNUNET_YES == ch->is_loopback)
  {
    ch->state = CADET_CHANNEL_OPEN_SENT;
    GCCH_handle_channel_open_ack (ch, NULL, port);
  }
  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);
  }
  /* give client it's initial supply of ACKs */
  GNUNET_assert (ntohl (cccd->ccn.channel_of_client) <
                 GNUNET_CADET_LOCAL_CHANNEL_ID_CLI);
  for (unsigned int i = 0; i < ch->max_pending_messages; i++)
    send_ack_to_client (ch, GNUNET_NO);
}
 
 
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);
}
 
 
void
GCCH_channel_local_destroy (struct CadetChannel *ch,
                            struct CadetClient *c,
                            struct GNUNET_CADET_ClientChannelNumber ccn)
{
  LOG (GNUNET_ERROR_TYPE_DEBUG,
       "%s asks for destruction of %s\n",
       GSC_2s (c),
       GCCH_2s (ch));
  GNUNET_assert (NULL != c);
  if ((NULL != ch->owner) && (c == ch->owner->c) &&
      (ccn.channel_of_client == ch->owner->ccn.channel_of_client))
  {
    free_channel_client (ch->owner);
    ch->owner = NULL;
  }
  else if ((NULL != ch->dest) && (c == ch->dest->c) &&
           (ccn.channel_of_client == ch->dest->ccn.channel_of_client))
  {
    free_channel_client (ch->dest);
    ch->dest = NULL;
  }
  else
  {
    GNUNET_assert (0);
  }
 
  if (GNUNET_YES == ch->destroy)
  {
    /* other end already destroyed, with the local client gone, no need
       to finish transmissions, just destroy immediately. */
    channel_destroy (ch);
    return;
  }
  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 ((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:
      break;
 
    default:
      GCT_send_channel_destroy (ch->t, ch->ctn);
    }
  }
  /* Nothing left to do, just finish destruction */
  channel_destroy (ch);
}
 
 
void
GCCH_handle_channel_open_ack (
  struct CadetChannel *ch,
  const struct GNUNET_CADET_ConnectionTunnelIdentifier *cti,
  const struct GNUNET_HashCode *port)
{
  switch (ch->state)
  {
  case CADET_CHANNEL_NEW:
    /* 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)
    {
      /* We're not the owner, wrong direction! */
      GNUNET_break_op (0);
      return;
    }
    if (0 != GNUNET_memcmp (&ch->port, port))
    {
      /* Other peer failed to provide the right port,
         refuse connection. */
      GNUNET_break_op (0);
      return;
    }
    LOG (GNUNET_ERROR_TYPE_DEBUG,
         "Received CHANNEL_OPEN_ACK for waiting %s, entering READY state\n",
         GCCH_2s (ch));
    if (NULL != ch->retry_control_task)   /* can be NULL if ch->is_loopback */
    {
      GNUNET_SCHEDULER_cancel (ch->retry_control_task);
      ch->retry_control_task = NULL;
    }
    ch->state = CADET_CHANNEL_READY;
    /* On first connect, send client as many ACKs as we allow messages
       to be buffered! */
    for (unsigned int i = 0; i < ch->max_pending_messages; i++)
      send_ack_to_client (ch, GNUNET_YES);
    break;
 
  case CADET_CHANNEL_READY:
    /* duplicate ACK, maybe we retried the CREATE. Ignore. */
    LOG (GNUNET_ERROR_TYPE_DEBUG,
         "Received duplicate channel OPEN_ACK for %s\n",
         GCCH_2s (ch));
    GNUNET_STATISTICS_update (stats, "# duplicate CREATE_ACKs", 1, GNUNET_NO);
    break;
  }
}
 
 
static int
is_before (void *cls,
           struct CadetOutOfOrderMessage *m1,
           struct CadetOutOfOrderMessage *m2)
{
  int *duplicate = cls;
  uint32_t v1 = ntohl (m1->mid.mid);
  uint32_t v2 = ntohl (m2->mid.mid);
  uint32_t delta;
 
  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 */
    return GNUNET_NO;
  }
  else
  {
    /* result is small, thus v2 > v1, thus m1 < m2 */
    return GNUNET_YES;
  }
}
 
 
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;
  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 ((NULL == ch->owner) && (NULL == ch->dest))
  {
    /* This client is gone, but we still have messages to send to
       the other end (which is why @a ch is not yet dead).  However,
       we cannot pass messages to our client anymore. */
    LOG (GNUNET_ERROR_TYPE_DEBUG,
         "Dropping incoming payload on %s as this end is already closed\n",
         GCCH_2s (ch));
    /* send back DESTROY notification to stop further retransmissions! */
    if (GNUNET_YES == ch->destroy)
      GCT_send_channel_destroy (ch->t, ch->ctn);
    return;
  }
  payload_size = ntohs (msg->header.size) - sizeof(*msg);
  env = GNUNET_MQ_msg_extra (ld,
                             payload_size,
                             GNUNET_MESSAGE_TYPE_CADET_LOCAL_DATA);
  ld->ccn = (NULL == ch->dest) ? ch->owner->ccn : ch->dest->ccn;
  GNUNET_memcpy (&ld[1], &msg[1], payload_size);
  ccc = (NULL != ch->owner) ? ch->owner : ch->dest;
  if (GNUNET_YES == ccc->client_ready)
  {
    /*
     * We ad-hoc send the message if
     * - The channel is out-of-order
     * - The channel is reliable and MID matches next expected MID
     * - The channel is unreliable and MID is before lowest seen MID
     */if ((GNUNET_YES == ch->out_of_order) ||
        ((msg->mid.mid == ch->mid_recv.mid) && (GNUNET_YES == ch->reliable)) ||
        ((GNUNET_NO == ch->reliable) &&
         (ntohl (msg->mid.mid) >= ntohl (ch->mid_recv.mid)) &&
         ((NULL == ccc->head_recv) ||
          (ntohl (msg->mid.mid) < ntohl (ccc->head_recv->mid.mid)))))
    {
      LOG (GNUNET_ERROR_TYPE_DEBUG,
           "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;
      GSC_send_to_client (ccc->c, env);
      if (GNUNET_NO == ch->out_of_order)
        ch->mid_recv.mid = htonl (1 + ntohl (msg->mid.mid));
      else
        ch->mid_recv.mid = htonl (1 + ntohl (ch->mid_recv.mid));
      ch->mid_futures >>= 1;
      if ((GNUNET_YES == ch->out_of_order) && (GNUNET_NO == ch->reliable))
      {
        /* possibly shift by more if we skipped messages */
        uint64_t d = htonl (msg->mid.mid) - 1 - ntohl (ch->mid_recv.mid);
 
        if (d > 63)
          ch->mid_futures = 0;
        else
          ch->mid_futures >>= d;
        ch->mid_recv.mid = htonl (1 + ntohl (msg->mid.mid));
      }
      send_channel_data_ack (ch);
      return;
    }
  }
 
  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))
    {
      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;
    }
    /* mark bit for future ACKs */
    delta = mid_msg - mid_min - 1;   /* overflow/underflow are OK here */
    if (delta < 64)
    {
      if (0 != (ch->mid_futures & (1LLU << delta)))
      {
        /* 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;
      }
      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,
           (unsigned long long) ch->mid_futures);
    }
  }
  else /* ! ch->reliable */
  {
    struct CadetOutOfOrderMessage *next_msg;
 
    if ((NULL != ccc->head_recv) && (GNUNET_YES == ccc->client_ready))
    {
      next_msg = ccc->head_recv;
      LOG (GNUNET_ERROR_TYPE_DEBUG,
           "Giving queued MID %u from %s to client %s\n",
           ntohl (next_msg->mid.mid),
           GCCH_2s (ch),
           GSC_2s (ccc->c));
      ccc->client_ready = GNUNET_NO;
      GSC_send_to_client (ccc->c, next_msg->env);
      ch->mid_recv.mid = htonl (1 + ntohl (next_msg->mid.mid));
      ch->mid_futures >>= 1;
      send_channel_data_ack (ch);
      GNUNET_CONTAINER_DLL_remove (ccc->head_recv, ccc->tail_recv, next_msg);
      ccc->num_recv--;
      /* Do not process duplicate MID */
      if (msg->mid.mid == next_msg->mid.mid)     /* Duplicate */
      {
        /* Duplicate within the queue, drop */
        LOG (GNUNET_ERROR_TYPE_DEBUG,
             "Message on %s (mid %u) dropped, duplicate\n",
             GCCH_2s (ch),
             ntohl (msg->mid.mid));
        GNUNET_free (next_msg);
        GNUNET_MQ_discard (env);
        return;
      }
      GNUNET_free (next_msg);
    }
 
    if (ntohl (msg->mid.mid) < ntohl (ch->mid_recv.mid)) /* Old */
    {
      /* Duplicate within the queue, drop */
      LOG (GNUNET_ERROR_TYPE_DEBUG,
           "Message on %s (mid %u) dropped, old.\n",
           GCCH_2s (ch),
           ntohl (msg->mid.mid));
      GNUNET_MQ_discard (env);
      return;
    }
 
    /* 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_assert (NULL != drop);
      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);
}
 
 
static void
data_sent_cb (void *cls,
              const struct GNUNET_CADET_ConnectionTunnelIdentifier *cid);
 
 
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,
                      &crm->data_message->ctn);
  GNUNET_assert (NULL == ch->retry_data_task);
}
 
 
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 == GNUNET_memcmp (cti, &crm->connection_taken))
    {
      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);
}
 
 
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)
  {
    /* not expecting ACKs on unreliable channel, odd */
    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 = 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. */
    LOG (GNUNET_ERROR_TYPE_DEBUG,
         "Duplicate DATA_ACK on %s, ignoring\n",
         GCCH_2s (ch));
    GNUNET_STATISTICS_update (stats, "# duplicate DATA_ACKs", 1, GNUNET_NO);
    return;
  }
  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);
}
 
 
void
GCCH_handle_remote_destroy (
  struct CadetChannel *ch,
  const struct GNUNET_CADET_ConnectionTunnelIdentifier *cti)
{
  struct CadetChannelClient *ccc;
 
  GNUNET_assert (GNUNET_NO == ch->is_loopback);
  LOG (GNUNET_ERROR_TYPE_DEBUG,
       "Received remote channel DESTROY for %s\n",
       GCCH_2s (ch));
  if (GNUNET_YES == ch->destroy)
  {
    /* Local client already gone, this is instant-death. */
    channel_destroy (ch);
    return;
  }
  ccc = (NULL != ch->owner) ? ch->owner : ch->dest;
  if ((NULL != ccc) && (NULL != ccc->head_recv))
  {
    LOG (GNUNET_ERROR_TYPE_WARNING,
         "Lost end of transmission due to remote shutdown on %s\n",
         GCCH_2s (ch));
    /* FIXME: change API to notify client about truncated transmission! */
  }
  ch->destroy = GNUNET_YES;
  if (NULL != ccc)
    GSC_handle_remote_channel_destroy (ccc->c, ccc->ccn, ch);
  channel_destroy (ch);
}
 
 
static int
cmp_crm_by_next_retry (void *cls,
                       struct CadetReliableMessage *crm1,
                       struct CadetReliableMessage *crm2)
{
  if (crm1->next_retry.abs_value_us < crm2->next_retry.abs_value_us)
    return GNUNET_YES;
  return GNUNET_NO;
}
 
 
static void
data_sent_cb (void *cls,
              const struct GNUNET_CADET_ConnectionTunnelIdentifier *cid)
{
  struct CadetReliableMessage *crm = cls;
  struct CadetChannel *ch = crm->ch;
 
  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, (NULL == ch->owner) ? GNUNET_NO : GNUNET_YES);
    return;
  }
  if (NULL == cid)
  {
    /* There was an error sending. */
    crm->num_transmissions = GNUNET_SYSERR;
  }
  else if (GNUNET_SYSERR != crm->num_transmissions)
  {
    /* 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);
  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)
  {
    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);
  }
}
 
 
int
GCCH_handle_local_data (struct CadetChannel *ch,
                        struct GNUNET_CADET_ClientChannelNumber sender_ccn,
                        const char *buf,
                        size_t buf_len)
{
  struct CadetReliableMessage *crm;
 
  if (ch->pending_messages >= ch->max_pending_messages)
  {
    GNUNET_break (0);  /* Fails: #5370 */
    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 ack_to_owner;
 
    env =
      GNUNET_MQ_msg_extra (ld, buf_len, GNUNET_MESSAGE_TYPE_CADET_LOCAL_DATA);
    if ((NULL != ch->owner) &&
        (sender_ccn.channel_of_client == ch->owner->ccn.channel_of_client))
    {
      receiver = ch->dest;
      ack_to_owner = GNUNET_YES;
    }
    else if ((NULL != ch->dest) &&
             (sender_ccn.channel_of_client == ch->dest->ccn.channel_of_client))
    {
      receiver = ch->owner;
      ack_to_owner = GNUNET_NO;
    }
    else
    {
      GNUNET_free (env);
      GNUNET_break (0);
      return GNUNET_SYSERR;
    }
    GNUNET_assert (NULL != receiver);
    ld->ccn = receiver->ccn;
    GNUNET_memcpy (&ld[1], buf, buf_len);
    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;
  }
 
  /* Everything is correct, send the message. */
  crm = GNUNET_malloc (sizeof(*crm));
  crm->ch = ch;
  crm->data_message = GNUNET_malloc (
    sizeof(struct GNUNET_CADET_ChannelAppDataMessage) + buf_len);
  crm->data_message->header.size =
    htons (sizeof(struct GNUNET_CADET_ChannelAppDataMessage) + buf_len);
  crm->data_message->header.type =
    htons (GNUNET_MESSAGE_TYPE_CADET_CHANNEL_APP_DATA);
  ch->mid_send.mid = htonl (ntohl (ch->mid_send.mid) + 1);
  crm->data_message->mid = ch->mid_send;
  crm->data_message->ctn = ch->ctn;
  GNUNET_memcpy (&crm->data_message[1], buf, buf_len);
  GNUNET_CONTAINER_DLL_insert_tail (ch->head_sent, ch->tail_sent, crm);
  LOG (GNUNET_ERROR_TYPE_DEBUG,
       "Sending message %u from local client to %s with %lu bytes\n",
       ntohl (crm->data_message->mid.mid),
       GCCH_2s (ch),
       (unsigned long) 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,
                      &crm->data_message->ctn);
  GNUNET_assert (NULL == ch->retry_data_task);
  return GNUNET_OK;
}
 
 
void
GCCH_handle_local_ack (struct CadetChannel *ch,
                       struct GNUNET_CADET_ClientChannelNumber client_ccn)
{
  struct CadetChannelClient *ccc;
  struct CadetOutOfOrderMessage *com;
 
  if ((NULL != ch->owner) &&
      (ch->owner->ccn.channel_of_client == client_ccn.channel_of_client))
    ccc = ch->owner;
  else if ((NULL != ch->dest) &&
           (ch->dest->ccn.channel_of_client == client_ccn.channel_of_client))
    ccc = ch->dest;
  else
    GNUNET_assert (0);
  ccc->client_ready = GNUNET_YES;
  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 ((NULL != ch->owner) &&
        (ccc->ccn.channel_of_client == ch->owner->ccn.channel_of_client))
    {
      to_owner = GNUNET_NO;
    }
    else
    {
      GNUNET_assert ((NULL != ch->dest) && (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_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 */
  }
 
  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);
  send_channel_data_ack (ch);
  if (NULL != ccc->head_recv)
    return;
  if (GNUNET_NO == ch->destroy)
    return;
  GCT_send_channel_destroy (ch->t, ch->ctn);
  channel_destroy (ch);
}
 
 
#define LOG2(level, ...) \
        GNUNET_log_from_nocheck (level, "cadet-chn", __VA_ARGS__)
 
 
void
GCCH_debug (struct CadetChannel *ch, enum GNUNET_ErrorType level)
{
#if ! defined(GNUNET_CULL_LOGGING)
  int do_log;
 
  do_log = GNUNET_get_log_call_status (level & (~GNUNET_ERROR_TYPE_BULK),
                                       "cadet-chn",
                                       __FILE__,
                                       __FUNCTION__,
                                       __LINE__);
  if (0 == do_log)
    return;
 
  if (NULL == ch)
  {
    LOG2 (level, "CHN *** DEBUG NULL CHANNEL ***\n");
    return;
  }
  LOG2 (level, "CHN %s:%X (%p)\n", GCT_2s (ch->t), ch->ctn.cn, ch);
  if (NULL != ch->owner)
  {
    LOG2 (level,
          "CHN origin %s ready %s local-id: %u\n",
          GSC_2s (ch->owner->c),
          ch->owner->client_ready ? "YES" : "NO",
          ntohl (ch->owner->ccn.channel_of_client));
  }
  if (NULL != ch->dest)
  {
    LOG2 (level,
          "CHN destination %s ready %s local-id: %u\n",
          GSC_2s (ch->dest->c),
          ch->dest->client_ready ? "YES" : "NO",
          ntohl (ch->dest->ccn.channel_of_client));
  }
  LOG2 (level,
        "CHN  Message IDs recv: %d (%llX), send: %d\n",
        ntohl (ch->mid_recv.mid),
        (unsigned long long) ch->mid_futures,
        ntohl (ch->mid_send.mid));
#endif
}
 
 
/* end of gnunet-service-cadet_channel.c */

TIMEOUT_CLOSED_PORT

#define TIMEOUT_CLOSED_PORT    GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_SECONDS, 30)

How long do we wait before dropping state about incoming connection to closed port?

Definition at line 57 of file gnunet-service-cadet_channel.c.

MIN_RTT_DELAY

#define MIN_RTT_DELAY    GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_MILLISECONDS, 75)

How long do we wait at least before retransmitting ever?

Definition at line 63 of file gnunet-service-cadet_channel.c.

MAX_OUT_OF_ORDER_DISTANCE

#define MAX_OUT_OF_ORDER_DISTANCE   1024

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...

Definition at line 76 of file gnunet-service-cadet_channel.c.

LOG2

#define LOG2	(		level,
			...
	)		GNUNET_log_from_nocheck (level, "cadet-chn", __VA_ARGS__)

Definition at line 1963 of file gnunet-service-cadet_channel.c.

Enumeration Type Documentation

CadetChannelState

enum CadetChannelState

All the states a channel can be in.

Enumerator
CADET_CHANNEL_NEW	Uninitialized status, should never appear in operation.
CADET_CHANNEL_LOOSE	Channel is to a port that is not open, we're waiting for the port to be opened.
CADET_CHANNEL_OPEN_SENT	CHANNEL_OPEN message sent, waiting for CHANNEL_OPEN_ACK.
CADET_CHANNEL_READY	Connection confirmed, ready to carry traffic.

Definition at line 82 of file gnunet-service-cadet_channel.c.

{
  CADET_CHANNEL_NEW,
 
  CADET_CHANNEL_LOOSE,
 
  CADET_CHANNEL_OPEN_SENT,
 
  CADET_CHANNEL_READY
};

Function Documentation

GCCH_assign_type_to_drop()

void GCCH_assign_type_to_drop	(	struct CadetChannel *	ch,
		const struct GNUNET_CADET_RequestDropCadetMessage *	message
	)

Assign type of message to drop.

Parameters

ch	CadetChannel to assign type to drop.
message	GNUNET_CADET_RequestDropCadetMessage to get the type from.

Definition at line 393 of file gnunet-service-cadet_channel.c.

{
 
  ch->type = message->type;
 
}

References ch, and GNUNET_CADET_RequestDropCadetMessage::type.

Referenced by handle_drop_message().

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GCCH_is_type_to_drop()

int GCCH_is_type_to_drop	(	struct CadetChannel *	ch,
		const struct GNUNET_MessageHeader *	message
	)

Check if type of message is the one to drop.

Parameters

ch	CadetChannel to check for message type to drop.
message	GNUNET_MessageHeader to compare the type with.

Definition at line 408 of file gnunet-service-cadet_channel.c.

{
 
  if (ch->type == message->type)
  {
    ch->type = 0;
    return GNUNET_YES;
  }
  else
    return GNUNET_NO;
}

References ch, GNUNET_NO, GNUNET_YES, and GNUNET_MessageHeader::type.

Referenced by GCT_send().

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GCCH_2s()

const char * GCCH_2s

(

const struct CadetChannel *

ch

)

Get the static string for identification of the channel.

Parameters

ch

Channel.

Returns

Static string with the channel IDs.

Definition at line 430 of file gnunet-service-cadet_channel.c.

{
  static char buf[128];
 
  GNUNET_snprintf (buf,
                   sizeof(buf),
                   "Channel %s:%s ctn:%X(%X/%X)",
                   (GNUNET_YES == ch->is_loopback)
                   ? "loopback"
                   : GNUNET_i2s (GCP_get_id (GCT_get_destination (ch->t))),
                   GNUNET_h2s (&ch->port),
                   ch->ctn.cn,
                   (NULL == ch->owner)
                   ? 0
                   : ntohl (ch->owner->ccn.channel_of_client),
                   (NULL == ch->dest)
                   ? 0
                   : ntohl (ch->dest->ccn.channel_of_client));
  return buf;
}

References GNUNET_CADET_Channel::ccn, ch, GNUNET_CADET_ClientChannelNumber::channel_of_client, GCP_get_id(), GCT_get_destination(), GNUNET_h2s(), GNUNET_i2s(), GNUNET_snprintf(), and GNUNET_YES.

Referenced by channel_destroy_iterator(), channel_open_sent_cb(), data_sent_cb(), GCCH_bind(), GCCH_channel_local_destroy(), GCCH_handle_channel_open_ack(), GCCH_handle_channel_plaintext_data(), GCCH_handle_channel_plaintext_data_ack(), GCCH_handle_duplicate_open(), GCCH_handle_local_ack(), GCCH_handle_local_data(), GCCH_handle_remote_destroy(), GCCH_tunnel_up(), GCT_add_channel(), GCT_remove_channel(), GSC_bind(), handle_channel_destroy(), handle_local_ack(), handle_local_data(), handle_matching_ack(), handle_plaintext_channel_destroy(), handle_plaintext_channel_open(), handle_plaintext_channel_open_ack(), retry_transmission(), send_channel_data_ack(), send_channel_open(), and send_open_ack().

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GCCH_hash_port()

void GCCH_hash_port	(	struct GNUNET_HashCode *	h_port,
		const struct GNUNET_HashCode *	port,
		const struct GNUNET_PeerIdentity *	listener
	)

Hash the port and initiator and listener to calculate the "challenge" h_port we send to the other peer on GNUNET_MESSAGE_TYPE_CADET_CHANNEL_OPEN.

Parameters

[out]	h_port	set to the hash of port, initiator and listener
	port	cadet port, as seen by CADET clients
	listener	peer that is listining on port

Definition at line 462 of file gnunet-service-cadet_channel.c.

{
  struct GNUNET_HashContext *hc;
 
  hc = GNUNET_CRYPTO_hash_context_start ();
  GNUNET_CRYPTO_hash_context_read (hc, port, sizeof(*port));
  GNUNET_CRYPTO_hash_context_read (hc, listener, sizeof(*listener));
  GNUNET_CRYPTO_hash_context_finish (hc, h_port);
  LOG (GNUNET_ERROR_TYPE_DEBUG,
       "Calculated port hash %s\n",
       GNUNET_h2s (h_port));
}

References GNUNET_CRYPTO_hash_context_finish(), GNUNET_CRYPTO_hash_context_read(), GNUNET_CRYPTO_hash_context_start(), GNUNET_ERROR_TYPE_DEBUG, GNUNET_h2s(), LOG, and port.

Referenced by GCCH_channel_local_new(), and handle_port_open().

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GCCH_get_id()

struct GNUNET_CADET_ChannelTunnelNumber GCCH_get_id

(

const struct CadetChannel *

ch

)

Get the channel's public ID.

Parameters

ch

Channel.

Returns

ID used to identify the channel with the remote peer.

Definition at line 486 of file gnunet-service-cadet_channel.c.

{
  return ch->ctn;
}

References ch.

free_channel_client()

static void free_channel_client ( struct CadetChannelClient *  ccc )

static

Release memory associated with ccc.

Parameters

ccc	data structure to clean up

Definition at line 498 of file gnunet-service-cadet_channel.c.

{
  struct CadetOutOfOrderMessage *com;
 
  while (NULL != (com = ccc->head_recv))
  {
    GNUNET_CONTAINER_DLL_remove (ccc->head_recv, ccc->tail_recv, com);
    ccc->num_recv--;
    GNUNET_MQ_discard (com->env);
    GNUNET_free (com);
  }
  GNUNET_free (ccc);
}

References CadetOutOfOrderMessage::env, GNUNET_CONTAINER_DLL_remove, GNUNET_free, GNUNET_MQ_discard(), CadetChannelClient::head_recv, CadetChannelClient::num_recv, and CadetChannelClient::tail_recv.

Referenced by channel_destroy(), and GCCH_channel_local_destroy().

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channel_destroy()

static void channel_destroy ( struct CadetChannel *  ch )

static

Destroy the given channel.

Parameters

ch	channel to destroy

Definition at line 519 of file gnunet-service-cadet_channel.c.

{
  struct CadetReliableMessage *crm;
 
  while (NULL != (crm = ch->head_sent))
  {
    GNUNET_assert (ch == crm->ch);
    if (NULL != crm->qe)
    {
      GCT_send_cancel (crm->qe);
      crm->qe = NULL;
    }
    GNUNET_CONTAINER_DLL_remove (ch->head_sent, ch->tail_sent, crm);
    GNUNET_free (crm->data_message);
    GNUNET_free (crm);
  }
  if (CADET_CHANNEL_LOOSE == ch->state)
  {
    GSC_drop_loose_channel (&ch->h_port, ch);
  }
  if (NULL != ch->owner)
  {
    free_channel_client (ch->owner);
    ch->owner = NULL;
  }
  if (NULL != ch->dest)
  {
    free_channel_client (ch->dest);
    ch->dest = NULL;
  }
  if (NULL != ch->last_control_qe)
  {
    GCT_send_cancel (ch->last_control_qe);
    ch->last_control_qe = NULL;
  }
  if (NULL != ch->retry_data_task)
  {
    GNUNET_SCHEDULER_cancel (ch->retry_data_task);
    ch->retry_data_task = NULL;
  }
  if (NULL != ch->retry_control_task)
  {
    GNUNET_SCHEDULER_cancel (ch->retry_control_task);
    ch->retry_control_task = NULL;
  }
  if (GNUNET_NO == ch->is_loopback)
  {
    GCT_remove_channel (ch->t, ch, ch->ctn);
    ch->t = NULL;
  }
  GNUNET_free (ch);
}

References CADET_CHANNEL_LOOSE, ch, CadetReliableMessage::ch, CadetReliableMessage::data_message, free_channel_client(), GCT_remove_channel(), GCT_send_cancel(), GNUNET_assert, GNUNET_CONTAINER_DLL_remove, GNUNET_free, GNUNET_NO, GNUNET_SCHEDULER_cancel(), GSC_drop_loose_channel(), and CadetReliableMessage::qe.

Referenced by GCCH_channel_local_destroy(), GCCH_handle_local_ack(), GCCH_handle_remote_destroy(), reconnect(), signal_remote_destroy_cb(), and timeout_closed_cb().

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send_channel_open()

static void send_channel_open ( void *  cls )

static

Send a channel create message.

Send a channel open message.

Parameters

cls	Channel for which to send.

Definition at line 614 of file gnunet-service-cadet_channel.c.

{
  struct CadetChannel *ch = cls;
  struct GNUNET_CADET_ChannelOpenMessage msgcc;
 
  ch->retry_control_task = NULL;
  LOG (GNUNET_ERROR_TYPE_DEBUG,
       "Sending CHANNEL_OPEN message for %s\n",
       GCCH_2s (ch));
  msgcc.header.size = htons (sizeof(msgcc));
  msgcc.header.type = htons (GNUNET_MESSAGE_TYPE_CADET_CHANNEL_OPEN);
  // TODO This will be removed in a major release, because this will be a protocol breaking change. We set the deprecated "reliable" bit here that was removed.
  msgcc.opt = 2;
  msgcc.h_port = ch->h_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, &msgcc.ctn);
  GNUNET_assert (NULL == ch->retry_control_task);
}

References CADET_CHANNEL_OPEN_SENT, ch, channel_open_sent_cb(), GNUNET_CADET_ChannelOpenMessage::ctn, GCCH_2s(), GCT_send(), GCT_send_cancel(), GNUNET_assert, GNUNET_ERROR_TYPE_DEBUG, GNUNET_MESSAGE_TYPE_CADET_CHANNEL_OPEN, GNUNET_CADET_ChannelOpenMessage::h_port, GNUNET_CADET_ChannelOpenMessage::header, LOG, GNUNET_CADET_ChannelOpenMessage::opt, GNUNET_MessageHeader::size, and GNUNET_MessageHeader::type.

Referenced by channel_open_sent_cb(), and GCCH_tunnel_up().

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channel_open_sent_cb()

static void channel_open_sent_cb ( void *  cls, const struct GNUNET_CADET_ConnectionTunnelIdentifier *  cid  )

static

Function called once the tunnel confirms that we sent the create message.

Delays for a bit until we retry.

Parameters

cls	our struct CadetChannel.
cid	identifier of the connection within the tunnel, NULL if transmission failed

Definition at line 591 of file gnunet-service-cadet_channel.c.

{
  struct CadetChannel *ch = cls;
 
  GNUNET_assert (NULL != ch->last_control_qe);
  ch->last_control_qe = NULL;
  ch->retry_time = GNUNET_TIME_STD_BACKOFF (ch->retry_time);
  LOG (GNUNET_ERROR_TYPE_DEBUG,
       "Sent CADET_CHANNEL_OPEN on %s, retrying in %s\n",
       GCCH_2s (ch),
       GNUNET_STRINGS_relative_time_to_string (ch->retry_time, GNUNET_YES));
  ch->retry_control_task =
    GNUNET_SCHEDULER_add_delayed (ch->retry_time, &send_channel_open, ch);
}

References ch, GCCH_2s(), GNUNET_assert, GNUNET_ERROR_TYPE_DEBUG, GNUNET_SCHEDULER_add_delayed(), GNUNET_STRINGS_relative_time_to_string(), GNUNET_TIME_STD_BACKOFF, GNUNET_YES, LOG, and send_channel_open().

Referenced by send_channel_open().

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GCCH_tunnel_up()

void GCCH_tunnel_up

(

struct CadetChannel *

ch

)

Function called once and only once after a channel was bound to its tunnel via GCT_add_channel() is ready for transmission.

Note that this is only the case for channels that this peer initiates, as for incoming channels we assume that they are ready for transmission immediately upon receiving the open message. Used to bootstrap the GCT_send() process.

Parameters

ch	the channel for which the tunnel is now ready

Definition at line 649 of file gnunet-service-cadet_channel.c.

{
  GNUNET_assert (NULL == ch->retry_control_task);
  LOG (GNUNET_ERROR_TYPE_DEBUG,
       "Tunnel up, sending CHANNEL_OPEN on %s now\n",
       GCCH_2s (ch));
  ch->retry_control_task = GNUNET_SCHEDULER_add_now (&send_channel_open, ch);
}

References ch, GCCH_2s(), GNUNET_assert, GNUNET_ERROR_TYPE_DEBUG, GNUNET_SCHEDULER_add_now(), LOG, and send_channel_open().

Referenced by GCT_add_channel(), and notify_tunnel_up_cb().

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GCCH_channel_local_new()

struct CadetChannel * GCCH_channel_local_new	(	struct CadetClient *	owner,
		struct GNUNET_CADET_ClientChannelNumber	owner_id,
		struct CadetPeer *	destination,
		const struct GNUNET_HashCode *	port,
		uint32_t	options
	)

Create a new channel.

Parameters

owner	local client owning the channel
owner_id	local chid of this channel at the owner
destination	peer to which we should build the channel
port	desired port at destination
options	options for the channel

Returns

handle to the new channel

Definition at line 660 of file gnunet-service-cadet_channel.c.

{
  const struct GNUNET_PeerIdentity *my_identity;
  struct CadetChannel *ch;
  struct CadetChannelClient *ccco;
 
  my_identity = GNUNET_PILS_get_identity (pils);
  GNUNET_assert (my_identity);
 
  ccco = GNUNET_new (struct CadetChannelClient);
  ccco->c = owner;
  ccco->ccn = ccn;
  ccco->client_ready = GNUNET_YES;
 
  ch = GNUNET_new (struct CadetChannel);
  ch->mid_recv.mid = htonl (1);  /* The OPEN_ACK counts as message 0! */
  ch->nobuffer = GNUNET_NO;
  ch->reliable = GNUNET_YES;
  ch->out_of_order = GNUNET_NO;
  ch->max_pending_messages =
    (ch->nobuffer) ? 1 : 4; /* FIXME: 4!? Do not hardcode! */
  ch->owner = ccco;
  ch->port = *port;
  GCCH_hash_port (&ch->h_port, port, GCP_get_id (destination));
  if (0 == GNUNET_memcmp (my_identity, GCP_get_id (destination)))
  {
    struct OpenPort *op;
 
    ch->is_loopback = GNUNET_YES;
    op = GNUNET_CONTAINER_multihashmap_get (open_ports, &ch->h_port);
    if (NULL == op)
    {
      /* port closed, wait for it to possibly open */
      ch->state = CADET_CHANNEL_LOOSE;
      (void) GNUNET_CONTAINER_multihashmap_put (
        loose_channels,
        &ch->h_port,
        ch,
        GNUNET_CONTAINER_MULTIHASHMAPOPTION_MULTIPLE);
      LOG (GNUNET_ERROR_TYPE_DEBUG,
           "Created loose incoming loopback channel to port %s\n",
           GNUNET_h2s (&ch->port));
    }
    else
    {
      GCCH_bind (ch, op->c, &op->port);
    }
  }
  else
  {
    ch->t = GCP_get_tunnel (destination, GNUNET_YES);
    ch->retry_time = CADET_INITIAL_RETRANSMIT_TIME;
    ch->ctn = GCT_add_channel (ch->t, ch);
  }
  GNUNET_STATISTICS_update (stats, "# channels", 1, GNUNET_NO);
  LOG (GNUNET_ERROR_TYPE_DEBUG,
       "Created channel to port %s at peer %s for %s using %s\n",
       GNUNET_h2s (port),
       GCP_2s (destination),
       GSC_2s (owner),
       (GNUNET_YES == ch->is_loopback) ? "loopback" : GCT_2s (ch->t));
  return ch;
}

References CadetChannelClient::c, CADET_CHANNEL_LOOSE, CADET_INITIAL_RETRANSMIT_TIME, CadetChannelClient::ccn, ch, CadetChannelClient::client_ready, GCCH_bind(), GCCH_hash_port(), GCP_2s(), GCP_get_id(), GCP_get_tunnel(), GCT_2s(), GCT_add_channel(), GNUNET_assert, GNUNET_CONTAINER_multihashmap_get(), GNUNET_CONTAINER_multihashmap_put(), GNUNET_CONTAINER_MULTIHASHMAPOPTION_MULTIPLE, GNUNET_ERROR_TYPE_DEBUG, GNUNET_h2s(), GNUNET_memcmp, GNUNET_new, GNUNET_NO, GNUNET_PILS_get_identity(), GNUNET_STATISTICS_update(), GNUNET_YES, GSC_2s(), LOG, loose_channels, my_identity, op, open_ports, pils, port, and stats.

Referenced by handle_channel_create().

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timeout_closed_cb()

static void timeout_closed_cb ( void *  cls )

static

We had an incoming channel to a port that is closed.

It has not been opened for a while, drop it.

Parameters

cls	the channel to drop

Definition at line 736 of file gnunet-service-cadet_channel.c.

{
  struct CadetChannel *ch = cls;
 
  ch->retry_control_task = NULL;
  LOG (GNUNET_ERROR_TYPE_DEBUG,
       "Closing incoming channel to port %s from peer %s due to timeout\n",
       GNUNET_h2s (&ch->port),
       GCP_2s (GCT_get_destination (ch->t)));
  channel_destroy (ch);
}

References ch, channel_destroy(), GCP_2s(), GCT_get_destination(), GNUNET_ERROR_TYPE_DEBUG, GNUNET_h2s(), and LOG.

Referenced by GCCH_channel_incoming_new().

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GCCH_channel_incoming_new()

struct CadetChannel * GCCH_channel_incoming_new	(	struct CadetTunnel *	t,
		struct GNUNET_CADET_ChannelTunnelNumber	chid,
		const struct GNUNET_HashCode *	h_port,
		uint32_t	options
	)

Create a new channel based on a request coming in over the network.

Parameters

t	tunnel to the remote peer
chid	identifier of this channel in the tunnel
h_port	hash of desired local port
options	options for the channel

Returns

handle to the new channel

Definition at line 750 of file gnunet-service-cadet_channel.c.

{
  struct CadetChannel *ch;
  struct OpenPort *op;
 
  ch = GNUNET_new (struct CadetChannel);
  ch->h_port = *h_port;
  ch->t = t;
  ch->ctn = ctn;
  ch->retry_time = CADET_INITIAL_RETRANSMIT_TIME;
  ch->nobuffer = GNUNET_NO;
  ch->reliable = GNUNET_YES;
  ch->out_of_order = GNUNET_NO;
  ch->max_pending_messages =
    (ch->nobuffer) ? 1 : 4; /* FIXME: 4!? Do not hardcode! */
  GNUNET_STATISTICS_update (stats, "# channels", 1, GNUNET_NO);
 
  op = GNUNET_CONTAINER_multihashmap_get (open_ports, h_port);
  if (NULL == op)
  {
    /* port closed, wait for it to possibly open */
    ch->state = CADET_CHANNEL_LOOSE;
    (void) GNUNET_CONTAINER_multihashmap_put (
      loose_channels,
      &ch->h_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,
                                                           ch);
    LOG (GNUNET_ERROR_TYPE_DEBUG,
         "Created loose incoming channel to port %s from peer %s\n",
         GNUNET_h2s (&ch->port),
         GCP_2s (GCT_get_destination (ch->t)));
  }
  else
  {
    GCCH_bind (ch, op->c, &op->port);
  }
  GNUNET_STATISTICS_update (stats, "# channels", 1, GNUNET_NO);
  return ch;
}

References CADET_CHANNEL_LOOSE, CADET_INITIAL_RETRANSMIT_TIME, ch, GCCH_bind(), GCP_2s(), GCT_get_destination(), GNUNET_assert, GNUNET_CONTAINER_multihashmap_get(), GNUNET_CONTAINER_multihashmap_put(), GNUNET_CONTAINER_MULTIHASHMAPOPTION_MULTIPLE, GNUNET_ERROR_TYPE_DEBUG, GNUNET_h2s(), GNUNET_new, GNUNET_NO, GNUNET_SCHEDULER_add_delayed(), GNUNET_STATISTICS_update(), GNUNET_YES, OpenPort::h_port, LOG, loose_channels, op, open_ports, stats, t, timeout_closed_cb(), and TIMEOUT_CLOSED_PORT.

Referenced by handle_plaintext_channel_open().

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send_ack_cb()

static void send_ack_cb ( void *  cls, const struct GNUNET_CADET_ConnectionTunnelIdentifier *  cid  )

static

Function called once the tunnel confirms that we sent the ACK message.

Just remembers it was sent, we do not expect ACKs for ACKs ;-).

Parameters

cls	our struct CadetChannel.
cid	identifier of the connection within the tunnel, NULL if transmission failed

Definition at line 808 of file gnunet-service-cadet_channel.c.

{
  struct CadetChannel *ch = cls;
 
  GNUNET_assert (NULL != ch->last_control_qe);
  ch->last_control_qe = NULL;
}

References ch, and GNUNET_assert.

Referenced by send_channel_data_ack(), and send_open_ack().

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send_channel_data_ack()

static void send_channel_data_ack ( struct CadetChannel *  ch )

static

Compute and send the current GNUNET_MESSAGE_TYPE_CADET_CHANNEL_APP_DATA_ACK to the other peer.

Parameters

ch	channel to send the GNUNET_MESSAGE_TYPE_CADET_CHANNEL_APP_DATA_ACK for

Definition at line 824 of file gnunet-service-cadet_channel.c.

{
  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));
  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, &msg.header, &send_ack_cb, ch,
                                  &msg.ctn);
}

References ch, GCCH_2s(), GCT_send(), GCT_send_cancel(), GNUNET_ERROR_TYPE_DEBUG, GNUNET_htonll(), GNUNET_MESSAGE_TYPE_CADET_CHANNEL_APP_DATA_ACK, GNUNET_NO, LOG, msg, send_ack_cb(), GNUNET_MessageHeader::size, and GNUNET_MessageHeader::type.

Referenced by GCCH_handle_channel_plaintext_data(), and GCCH_handle_local_ack().

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send_open_ack()

static void send_open_ack ( void *  cls )

static

Send our initial GNUNET_MESSAGE_TYPE_CADET_CHANNEL_OPEN_ACK to the client confirming that the connection is up.

Parameters

cls	the struct CadetChannel

Definition at line 854 of file gnunet-service-cadet_channel.c.

{
  struct CadetChannel *ch = cls;
  struct GNUNET_CADET_ChannelOpenAckMessage msg;
 
  ch->retry_control_task = NULL;
  LOG (GNUNET_ERROR_TYPE_DEBUG,
       "Sending CHANNEL_OPEN_ACK on %s\n",
       GCCH_2s (ch));
  msg.header.type = htons (GNUNET_MESSAGE_TYPE_CADET_CHANNEL_OPEN_ACK);
  msg.header.size = htons (sizeof(msg));
  msg.reserved = htonl (0);
  msg.ctn = ch->ctn;
  msg.port = ch->port;
  if (NULL != ch->last_control_qe)
    GCT_send_cancel (ch->last_control_qe);
  ch->last_control_qe = GCT_send (ch->t, &msg.header, &send_ack_cb, ch,
                                  &msg.ctn);
}

References ch, GCCH_2s(), GCT_send(), GCT_send_cancel(), GNUNET_ERROR_TYPE_DEBUG, GNUNET_MESSAGE_TYPE_CADET_CHANNEL_OPEN_ACK, LOG, msg, send_ack_cb(), GNUNET_MessageHeader::size, and GNUNET_MessageHeader::type.

Referenced by GCCH_bind(), and GCCH_handle_duplicate_open().

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GCCH_handle_duplicate_open()

void GCCH_handle_duplicate_open	(	struct CadetChannel *	ch,
		const struct GNUNET_CADET_ConnectionTunnelIdentifier *	cti
	)

We got a GNUNET_MESSAGE_TYPE_CADET_CHANNEL_OPEN message again for this channel.

If the binding was successful, (re)transmit the GNUNET_MESSAGE_TYPE_CADET_CHANNEL_OPEN_ACK.

Parameters

ch	channel that got the duplicate open
cti	identifier of the connection that delivered the message

Definition at line 884 of file gnunet-service-cadet_channel.c.

{
  if (NULL == ch->dest)
  {
    LOG (GNUNET_ERROR_TYPE_DEBUG,
         "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",
         GCCH_2s (ch));
    return;
  }
  LOG (GNUNET_ERROR_TYPE_DEBUG,
       "Retransmitting CHANNEL_OPEN_ACK on %s\n",
       GCCH_2s (ch));
  ch->retry_control_task = GNUNET_SCHEDULER_add_now (&send_open_ack, ch);
}

References ch, GCCH_2s(), GNUNET_ERROR_TYPE_DEBUG, GNUNET_SCHEDULER_add_now(), LOG, and send_open_ack().

Referenced by handle_plaintext_channel_open().

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send_ack_to_client()

static void send_ack_to_client ( struct CadetChannel *  ch, int  to_owner  )

static

Send a GNUNET_MESSAGE_TYPE_CADET_LOCAL_ACK to the client to solicit more messages.

Parameters

ch	channel the ack is for
to_owner	GNUNET_YES to send to owner, GNUNET_NO to send to dest

Definition at line 917 of file gnunet-service-cadet_channel.c.

{
  struct GNUNET_MQ_Envelope *env;
  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);
  ack->ccn = ccc->ccn;
  LOG (GNUNET_ERROR_TYPE_DEBUG,
       "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),
       ch->pending_messages,
       ch->max_pending_messages);
  GSC_send_to_client (ccc->c, env);
}

References CadetChannelClient::c, GNUNET_CADET_LocalAck::ccn, CadetChannelClient::ccn, ch, GNUNET_CADET_ClientChannelNumber::channel_of_client, env, GNUNET_assert, GNUNET_ERROR_TYPE_DEBUG, GNUNET_MESSAGE_TYPE_CADET_LOCAL_ACK, GNUNET_MQ_msg, GNUNET_YES, GSC_2s(), GSC_send_to_client(), and LOG.

Referenced by data_sent_cb(), GCCH_bind(), GCCH_handle_channel_open_ack(), GCCH_handle_local_ack(), GCCH_handle_local_data(), and handle_matching_ack().

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GCCH_bind()

void GCCH_bind	(	struct CadetChannel *	ch,
		struct CadetClient *	c,
		const struct GNUNET_HashCode *	port
	)

A client is bound to the port that we have a channel open to.

Send the acknowledgement for the connection request and establish the link with the client.

Parameters

ch	open incoming channel
c	client listening on the respective port
port	port number c is listening on

Definition at line 945 of file gnunet-service-cadet_channel.c.

{
  const struct GNUNET_PeerIdentity *my_identity;
  uint32_t options;
  struct CadetChannelClient *cccd;
 
  LOG (GNUNET_ERROR_TYPE_DEBUG,
       "Binding %s from %s to port %s of %s\n",
       GCCH_2s (ch),
       GCT_2s (ch->t),
       GNUNET_h2s (&ch->port),
       GSC_2s (c));
 
  my_identity = GNUNET_PILS_get_identity (pils);
  GNUNET_assert (my_identity);
 
  if (NULL != ch->retry_control_task)
  {
    /* there might be a timeout task here */
    GNUNET_SCHEDULER_cancel (ch->retry_control_task);
    ch->retry_control_task = NULL;
  }
  options = 0;
  cccd = GNUNET_new (struct CadetChannelClient);
  GNUNET_assert (NULL == ch->dest);
  ch->dest = cccd;
  ch->port = *port;
  cccd->c = c;
  cccd->client_ready = GNUNET_YES;
  cccd->ccn = GSC_bind (c,
                        ch,
                        (GNUNET_YES == ch->is_loopback)
                        ? GCP_get (my_identity, GNUNET_YES)
                        : GCT_get_destination (ch->t),
                        port,
                        options);
  GNUNET_assert (ntohl (cccd->ccn.channel_of_client) <
                 GNUNET_CADET_LOCAL_CHANNEL_ID_CLI);
  ch->mid_recv.mid = htonl (1);  /* The OPEN counts as message 0! */
  if (GNUNET_YES == ch->is_loopback)
  {
    ch->state = CADET_CHANNEL_OPEN_SENT;
    GCCH_handle_channel_open_ack (ch, NULL, port);
  }
  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);
  }
  /* give client it's initial supply of ACKs */
  GNUNET_assert (ntohl (cccd->ccn.channel_of_client) <
                 GNUNET_CADET_LOCAL_CHANNEL_ID_CLI);
  for (unsigned int i = 0; i < ch->max_pending_messages; i++)
    send_ack_to_client (ch, GNUNET_NO);
}

References CadetChannelClient::c, CADET_CHANNEL_OPEN_SENT, CADET_CHANNEL_READY, CadetChannelClient::ccn, ch, GNUNET_CADET_ClientChannelNumber::channel_of_client, CadetChannelClient::client_ready, GCCH_2s(), GCCH_handle_channel_open_ack(), GCP_get(), GCT_2s(), GCT_get_destination(), GNUNET_assert, GNUNET_CADET_LOCAL_CHANNEL_ID_CLI, GNUNET_ERROR_TYPE_DEBUG, GNUNET_h2s(), GNUNET_new, GNUNET_NO, GNUNET_PILS_get_identity(), GNUNET_SCHEDULER_add_now(), GNUNET_SCHEDULER_cancel(), GNUNET_YES, GSC_2s(), GSC_bind(), LOG, my_identity, options, pils, port, send_ack_to_client(), and send_open_ack().

Referenced by bind_loose_channel(), GCCH_channel_incoming_new(), and GCCH_channel_local_new().

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signal_remote_destroy_cb()

static void signal_remote_destroy_cb ( void *  cls )

static

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.

Parameters

cls	the struct CadetChannel where one of the ends is now dead

Definition at line 1013 of file gnunet-service-cadet_channel.c.

{
  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);
}

References CadetChannelClient::c, CadetChannelClient::ccn, ch, channel_destroy(), and GSC_handle_remote_channel_destroy().

Referenced by GCCH_channel_local_destroy().

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GCCH_channel_local_destroy()

void GCCH_channel_local_destroy	(	struct CadetChannel *	ch,
		struct CadetClient *	c,
		struct GNUNET_CADET_ClientChannelNumber	ccn
	)

Destroy locally created channel.

Called by the local client, so no need to tell the client.

Parameters

ch	channel to destroy
c	client that caused the destruction
ccn	client number of the client c

Definition at line 1035 of file gnunet-service-cadet_channel.c.

{
  LOG (GNUNET_ERROR_TYPE_DEBUG,
       "%s asks for destruction of %s\n",
       GSC_2s (c),
       GCCH_2s (ch));
  GNUNET_assert (NULL != c);
  if ((NULL != ch->owner) && (c == ch->owner->c) &&
      (ccn.channel_of_client == ch->owner->ccn.channel_of_client))
  {
    free_channel_client (ch->owner);
    ch->owner = NULL;
  }
  else if ((NULL != ch->dest) && (c == ch->dest->c) &&
           (ccn.channel_of_client == ch->dest->ccn.channel_of_client))
  {
    free_channel_client (ch->dest);
    ch->dest = NULL;
  }
  else
  {
    GNUNET_assert (0);
  }
 
  if (GNUNET_YES == ch->destroy)
  {
    /* other end already destroyed, with the local client gone, no need
       to finish transmissions, just destroy immediately. */
    channel_destroy (ch);
    return;
  }
  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 ((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:
      break;
 
    default:
      GCT_send_channel_destroy (ch->t, ch->ctn);
    }
  }
  /* Nothing left to do, just finish destruction */
  channel_destroy (ch);
}

References CadetChannelClient::c, CADET_CHANNEL_LOOSE, CADET_CHANNEL_NEW, GNUNET_CADET_Channel::ccn, CadetChannelClient::ccn, ch, channel_destroy(), GNUNET_CADET_ClientChannelNumber::channel_of_client, free_channel_client(), GCCH_2s(), GCT_send_channel_destroy(), GNUNET_assert, GNUNET_ERROR_TYPE_DEBUG, GNUNET_NO, GNUNET_SCHEDULER_add_now(), GNUNET_SCHEDULER_cancel(), GNUNET_YES, GSC_2s(), LOG, and signal_remote_destroy_cb().

Referenced by channel_destroy_iterator(), and handle_channel_destroy().

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GCCH_handle_channel_open_ack()

void GCCH_handle_channel_open_ack	(	struct CadetChannel *	ch,
		const struct GNUNET_CADET_ConnectionTunnelIdentifier *	cti,
		const struct GNUNET_HashCode *	port
	)

We got an acknowledgement for the creation of the channel (the port is open on the other side).

Verify that the other end really has the right port, and begin transmissions.

Parameters

ch	channel to destroy
cti	identifier of the connection that delivered the message, NULL if the ACK was inferred because we got payload or are on loopback
port	port number (needed to verify receiver knows the port)

Definition at line 1107 of file gnunet-service-cadet_channel.c.

{
  switch (ch->state)
  {
  case CADET_CHANNEL_NEW:
    /* 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)
    {
      /* We're not the owner, wrong direction! */
      GNUNET_break_op (0);
      return;
    }
    if (0 != GNUNET_memcmp (&ch->port, port))
    {
      /* Other peer failed to provide the right port,
         refuse connection. */
      GNUNET_break_op (0);
      return;
    }
    LOG (GNUNET_ERROR_TYPE_DEBUG,
         "Received CHANNEL_OPEN_ACK for waiting %s, entering READY state\n",
         GCCH_2s (ch));
    if (NULL != ch->retry_control_task)   /* can be NULL if ch->is_loopback */
    {
      GNUNET_SCHEDULER_cancel (ch->retry_control_task);
      ch->retry_control_task = NULL;
    }
    ch->state = CADET_CHANNEL_READY;
    /* On first connect, send client as many ACKs as we allow messages
       to be buffered! */
    for (unsigned int i = 0; i < ch->max_pending_messages; i++)
      send_ack_to_client (ch, GNUNET_YES);
    break;
 
  case CADET_CHANNEL_READY:
    /* duplicate ACK, maybe we retried the CREATE. Ignore. */
    LOG (GNUNET_ERROR_TYPE_DEBUG,
         "Received duplicate channel OPEN_ACK for %s\n",
         GCCH_2s (ch));
    GNUNET_STATISTICS_update (stats, "# duplicate CREATE_ACKs", 1, GNUNET_NO);
    break;
  }
}

References CADET_CHANNEL_LOOSE, CADET_CHANNEL_NEW, CADET_CHANNEL_OPEN_SENT, CADET_CHANNEL_READY, ch, GCCH_2s(), GNUNET_break, GNUNET_break_op, GNUNET_ERROR_TYPE_DEBUG, GNUNET_memcmp, GNUNET_NO, GNUNET_SCHEDULER_cancel(), GNUNET_STATISTICS_update(), GNUNET_YES, LOG, port, send_ack_to_client(), and stats.

Referenced by GCCH_bind(), and handle_plaintext_channel_open_ack().

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is_before()

static int is_before ( void *  cls, struct CadetOutOfOrderMessage *  m1, struct CadetOutOfOrderMessage *  m2  )

static

Test if element e1 comes before element e2.

Parameters

cls	closure, to a flag where we indicate duplicate packets
m1	a message of to sort
m2	another message to sort

Returns

GNUNET_YES if e1 < e2, otherwise GNUNET_NO

Definition at line 1173 of file gnunet-service-cadet_channel.c.

{
  int *duplicate = cls;
  uint32_t v1 = ntohl (m1->mid.mid);
  uint32_t v2 = ntohl (m2->mid.mid);
  uint32_t delta;
 
  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 */
    return GNUNET_NO;
  }
  else
  {
    /* result is small, thus v2 > v1, thus m1 < m2 */
    return GNUNET_YES;
  }
}

References delta, GNUNET_NO, GNUNET_YES, INT_MAX, ChannelMessageIdentifier::mid, and CadetOutOfOrderMessage::mid.

Referenced by GCCH_handle_channel_plaintext_data().

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GCCH_handle_channel_plaintext_data()

void GCCH_handle_channel_plaintext_data	(	struct CadetChannel *	ch,
		const struct GNUNET_CADET_ConnectionTunnelIdentifier *	cti,
		const struct GNUNET_CADET_ChannelAppDataMessage *	msg
	)

We got payload data for a channel.

Pass it on to the client and send an ACK to the other end (once flow control allows it!)

Parameters

ch	channel that got data
cti	identifier of the connection that delivered the message
msg	message that was received

We always send if possible in this case. It is guaranteed that the queued MID < received MID

Definition at line 1199 of file gnunet-service-cadet_channel.c.

{
  struct GNUNET_MQ_Envelope *env;
  struct GNUNET_CADET_LocalData *ld;
  struct CadetChannelClient *ccc;
  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 ((NULL == ch->owner) && (NULL == ch->dest))
  {
    /* This client is gone, but we still have messages to send to
       the other end (which is why @a ch is not yet dead).  However,
       we cannot pass messages to our client anymore. */
    LOG (GNUNET_ERROR_TYPE_DEBUG,
         "Dropping incoming payload on %s as this end is already closed\n",
         GCCH_2s (ch));
    /* send back DESTROY notification to stop further retransmissions! */
    if (GNUNET_YES == ch->destroy)
      GCT_send_channel_destroy (ch->t, ch->ctn);
    return;
  }
  payload_size = ntohs (msg->header.size) - sizeof(*msg);
  env = GNUNET_MQ_msg_extra (ld,
                             payload_size,
                             GNUNET_MESSAGE_TYPE_CADET_LOCAL_DATA);
  ld->ccn = (NULL == ch->dest) ? ch->owner->ccn : ch->dest->ccn;
  GNUNET_memcpy (&ld[1], &msg[1], payload_size);
  ccc = (NULL != ch->owner) ? ch->owner : ch->dest;
  if (GNUNET_YES == ccc->client_ready)
  {
    /*
     * We ad-hoc send the message if
     * - The channel is out-of-order
     * - The channel is reliable and MID matches next expected MID
     * - The channel is unreliable and MID is before lowest seen MID
     */if ((GNUNET_YES == ch->out_of_order) ||
        ((msg->mid.mid == ch->mid_recv.mid) && (GNUNET_YES == ch->reliable)) ||
        ((GNUNET_NO == ch->reliable) &&
         (ntohl (msg->mid.mid) >= ntohl (ch->mid_recv.mid)) &&
         ((NULL == ccc->head_recv) ||
          (ntohl (msg->mid.mid) < ntohl (ccc->head_recv->mid.mid)))))
    {
      LOG (GNUNET_ERROR_TYPE_DEBUG,
           "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;
      GSC_send_to_client (ccc->c, env);
      if (GNUNET_NO == ch->out_of_order)
        ch->mid_recv.mid = htonl (1 + ntohl (msg->mid.mid));
      else
        ch->mid_recv.mid = htonl (1 + ntohl (ch->mid_recv.mid));
      ch->mid_futures >>= 1;
      if ((GNUNET_YES == ch->out_of_order) && (GNUNET_NO == ch->reliable))
      {
        /* possibly shift by more if we skipped messages */
        uint64_t d = htonl (msg->mid.mid) - 1 - ntohl (ch->mid_recv.mid);
 
        if (d > 63)
          ch->mid_futures = 0;
        else
          ch->mid_futures >>= d;
        ch->mid_recv.mid = htonl (1 + ntohl (msg->mid.mid));
      }
      send_channel_data_ack (ch);
      return;
    }
  }
 
  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))
    {
      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;
    }
    /* mark bit for future ACKs */
    delta = mid_msg - mid_min - 1;   /* overflow/underflow are OK here */
    if (delta < 64)
    {
      if (0 != (ch->mid_futures & (1LLU << delta)))
      {
        /* 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;
      }
      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,
           (unsigned long long) ch->mid_futures);
    }
  }
  else /* ! ch->reliable */
  {
    struct CadetOutOfOrderMessage *next_msg;
 
    if ((NULL != ccc->head_recv) && (GNUNET_YES == ccc->client_ready))
    {
      next_msg = ccc->head_recv;
      LOG (GNUNET_ERROR_TYPE_DEBUG,
           "Giving queued MID %u from %s to client %s\n",
           ntohl (next_msg->mid.mid),
           GCCH_2s (ch),
           GSC_2s (ccc->c));
      ccc->client_ready = GNUNET_NO;
      GSC_send_to_client (ccc->c, next_msg->env);
      ch->mid_recv.mid = htonl (1 + ntohl (next_msg->mid.mid));
      ch->mid_futures >>= 1;
      send_channel_data_ack (ch);
      GNUNET_CONTAINER_DLL_remove (ccc->head_recv, ccc->tail_recv, next_msg);
      ccc->num_recv--;
      /* Do not process duplicate MID */
      if (msg->mid.mid == next_msg->mid.mid)     /* Duplicate */
      {
        /* Duplicate within the queue, drop */
        LOG (GNUNET_ERROR_TYPE_DEBUG,
             "Message on %s (mid %u) dropped, duplicate\n",
             GCCH_2s (ch),
             ntohl (msg->mid.mid));
        GNUNET_free (next_msg);
        GNUNET_MQ_discard (env);
        return;
      }
      GNUNET_free (next_msg);
    }
 
    if (ntohl (msg->mid.mid) < ntohl (ch->mid_recv.mid)) /* Old */
    {
      /* Duplicate within the queue, drop */
      LOG (GNUNET_ERROR_TYPE_DEBUG,
           "Message on %s (mid %u) dropped, old.\n",
           GCCH_2s (ch),
           ntohl (msg->mid.mid));
      GNUNET_MQ_discard (env);
      return;
    }
 
    /* 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_assert (NULL != drop);
      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);
}

References CadetChannelClient::c, GNUNET_CADET_Channel::ccn, GNUNET_CADET_LocalData::ccn, CadetChannelClient::ccn, ch, GNUNET_CADET_ClientChannelNumber::channel_of_client, CadetChannelClient::client_ready, d, delta, env, CadetOutOfOrderMessage::env, GCCH_2s(), GCT_send_channel_destroy(), GNUNET_assert, GNUNET_CONTAINER_DLL_insert_sorted, GNUNET_CONTAINER_DLL_remove, GNUNET_ERROR_TYPE_DEBUG, GNUNET_free, GNUNET_memcpy, GNUNET_MESSAGE_TYPE_CADET_LOCAL_DATA, GNUNET_MQ_discard(), GNUNET_MQ_msg_extra, GNUNET_new, GNUNET_NO, GNUNET_STATISTICS_update(), GNUNET_YES, GSC_2s(), GSC_send_to_client(), CadetChannelClient::head_recv, is_before(), LOG, ChannelMessageIdentifier::mid, CadetOutOfOrderMessage::mid, msg, CadetChannelClient::num_recv, send_channel_data_ack(), GNUNET_MessageHeader::size, stats, and CadetChannelClient::tail_recv.

Referenced by handle_plaintext_data().

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data_sent_cb()

static void data_sent_cb ( void *  cls, const struct GNUNET_CADET_ConnectionTunnelIdentifier *  cid  )

static

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).

Parameters

cls	the struct CadetReliableMessage that was sent
cid	identifier of the connection within the tunnel, NULL if transmission failed

Definition at line 1682 of file gnunet-service-cadet_channel.c.

{
  struct CadetReliableMessage *crm = cls;
  struct CadetChannel *ch = crm->ch;
 
  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, (NULL == ch->owner) ? GNUNET_NO : GNUNET_YES);
    return;
  }
  if (NULL == cid)
  {
    /* There was an error sending. */
    crm->num_transmissions = GNUNET_SYSERR;
  }
  else if (GNUNET_SYSERR != crm->num_transmissions)
  {
    /* 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);
  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)
  {
    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);
  }
}

References CadetConnectionMetrics::aged_latency, ch, CadetReliableMessage::ch, CadetConnection::cid, cmp_crm_by_next_retry(), CadetReliableMessage::connection_taken, CadetReliableMessage::data_message, CadetReliableMessage::first_transmission_time, GCC_ack_expected(), GCC_get_metrics(), GCC_lookup(), GCCH_2s(), GNUNET_assert, GNUNET_CONTAINER_DLL_insert_sorted, GNUNET_CONTAINER_DLL_remove, GNUNET_ERROR_TYPE_DEBUG, GNUNET_free, GNUNET_NO, GNUNET_SCHEDULER_add_at(), GNUNET_SCHEDULER_cancel(), GNUNET_STRINGS_relative_time_to_string(), GNUNET_SYSERR, GNUNET_TIME_absolute_get(), GNUNET_TIME_absolute_get_remaining(), GNUNET_TIME_relative_max(), GNUNET_TIME_relative_to_absolute(), GNUNET_TIME_STD_BACKOFF, GNUNET_YES, LOG, MIN_RTT_DELAY, CadetReliableMessage::num_transmissions, CadetConnection::off, CadetReliableMessage::qe, GNUNET_TIME_Relative::rel_value_us, CadetReliableMessage::retry_delay, retry_transmission(), and send_ack_to_client().

Referenced by GCCH_handle_local_data(), and retry_transmission().

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retry_transmission()

static void retry_transmission ( void *  cls )

static

We need to retry a transmission, the last one took too long to be acknowledged.

Parameters

cls	the struct CadetChannel where we need to retransmit

Definition at line 1471 of file gnunet-service-cadet_channel.c.

{
  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,
                      &crm->data_message->ctn);
  GNUNET_assert (NULL == ch->retry_data_task);
}

References ch, GNUNET_CADET_ChannelAppDataMessage::ctn, CadetReliableMessage::data_message, data_sent_cb(), GCCH_2s(), GCT_send(), GNUNET_assert, GNUNET_ERROR_TYPE_DEBUG, GNUNET_CADET_ChannelAppDataMessage::header, LOG, ChannelMessageIdentifier::mid, GNUNET_CADET_ChannelAppDataMessage::mid, and CadetReliableMessage::qe.

Referenced by data_sent_cb(), and GCCH_handle_channel_plaintext_data_ack().

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handle_matching_ack()

static void handle_matching_ack ( struct CadetChannel *  ch, const struct GNUNET_CADET_ConnectionTunnelIdentifier *  cti, struct CadetReliableMessage *  crm  )

static

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.

Parameters

ch	the channel that got the PLAINTEXT_DATA_ACK
cti	identifier of the connection that delivered the message
crm	the message that got acknowledged

Definition at line 1497 of file gnunet-service-cadet_channel.c.

{
  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 == GNUNET_memcmp (cti, &crm->connection_taken))
    {
      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);
}

References ch, CadetReliableMessage::connection_taken, CadetReliableMessage::data_message, CadetReliableMessage::first_transmission_time, GCC_ack_observed(), GCC_latency_observed(), GCCH_2s(), GCT_send_cancel(), GNUNET_assert, GNUNET_CONTAINER_DLL_remove, GNUNET_ERROR_TYPE_DEBUG, GNUNET_free, GNUNET_memcmp, GNUNET_NO, GNUNET_TIME_absolute_get_duration(), GNUNET_YES, LOG, ChannelMessageIdentifier::mid, GNUNET_CADET_ChannelAppDataMessage::mid, CadetReliableMessage::num_transmissions, CadetReliableMessage::qe, and send_ack_to_client().

Referenced by GCCH_handle_channel_plaintext_data_ack().

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GCCH_handle_channel_plaintext_data_ack()

void GCCH_handle_channel_plaintext_data_ack	(	struct CadetChannel *	ch,
		const struct GNUNET_CADET_ConnectionTunnelIdentifier *	cti,
		const struct GNUNET_CADET_ChannelDataAckMessage *	ack
	)

We got an acknowledgement for payload data for a channel.

Possibly resume transmissions.

Parameters

ch	channel that got the ack
cti	identifier of the connection that delivered the message
ack	details about what was received

Definition at line 1539 of file gnunet-service-cadet_channel.c.

{
  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)
  {
    /* not expecting ACKs on unreliable channel, odd */
    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 = 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. */
    LOG (GNUNET_ERROR_TYPE_DEBUG,
         "Duplicate DATA_ACK on %s, ignoring\n",
         GCCH_2s (ch));
    GNUNET_STATISTICS_update (stats, "# duplicate DATA_ACKs", 1, GNUNET_NO);
    return;
  }
  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);
}

References ch, CadetReliableMessage::data_message, delta, GNUNET_CADET_ChannelDataAckMessage::futures, GCCH_2s(), GNUNET_break, GNUNET_break_op, GNUNET_ERROR_TYPE_DEBUG, GNUNET_htonll(), GNUNET_NO, GNUNET_SCHEDULER_add_at(), GNUNET_SCHEDULER_cancel(), GNUNET_STATISTICS_update(), GNUNET_YES, handle_matching_ack(), LOG, ChannelMessageIdentifier::mid, GNUNET_CADET_ChannelAppDataMessage::mid, GNUNET_CADET_ChannelDataAckMessage::mid, CadetReliableMessage::next, retry_transmission(), and stats.

Referenced by handle_plaintext_data_ack().

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GCCH_handle_remote_destroy()

void GCCH_handle_remote_destroy	(	struct CadetChannel *	ch,
		const struct GNUNET_CADET_ConnectionTunnelIdentifier *	cti
	)

Destroy channel, based on the other peer closing the connection.

Also needs to remove this channel from the tunnel.

FIXME: need to make it possible to defer destruction until we have received all messages up to the destroy, and right now the destroy message (and this API) fails to give is the information we need!

FIXME: also need to know if the other peer got a destroy from us before!

Parameters

ch	channel to destroy
cti	identifier of the connection that delivered the message, NULL if we are simulating receiving a destroy due to shutdown

Definition at line 1621 of file gnunet-service-cadet_channel.c.

{
  struct CadetChannelClient *ccc;
 
  GNUNET_assert (GNUNET_NO == ch->is_loopback);
  LOG (GNUNET_ERROR_TYPE_DEBUG,
       "Received remote channel DESTROY for %s\n",
       GCCH_2s (ch));
  if (GNUNET_YES == ch->destroy)
  {
    /* Local client already gone, this is instant-death. */
    channel_destroy (ch);
    return;
  }
  ccc = (NULL != ch->owner) ? ch->owner : ch->dest;
  if ((NULL != ccc) && (NULL != ccc->head_recv))
  {
    LOG (GNUNET_ERROR_TYPE_WARNING,
         "Lost end of transmission due to remote shutdown on %s\n",
         GCCH_2s (ch));
    /* FIXME: change API to notify client about truncated transmission! */
  }
  ch->destroy = GNUNET_YES;
  if (NULL != ccc)
    GSC_handle_remote_channel_destroy (ccc->c, ccc->ccn, ch);
  channel_destroy (ch);
}

References CadetChannelClient::c, CadetChannelClient::ccn, ch, channel_destroy(), GCCH_2s(), GNUNET_assert, GNUNET_ERROR_TYPE_DEBUG, GNUNET_ERROR_TYPE_WARNING, GNUNET_NO, GNUNET_YES, GSC_handle_remote_channel_destroy(), CadetChannelClient::head_recv, and LOG.

Referenced by destroy_remaining_channels(), and handle_plaintext_channel_destroy().

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cmp_crm_by_next_retry()

static int cmp_crm_by_next_retry ( void *  cls, struct CadetReliableMessage *  crm1, struct CadetReliableMessage *  crm2  )

static

Test if element e1 comes before element e2.

Parameters

cls	closure, to a flag where we indicate duplicate packets
crm1	an element of to sort
crm2	another element to sort

Returns

GNUNET_YES if e1 < e2, otherwise GNUNET_NO

Definition at line 1661 of file gnunet-service-cadet_channel.c.

{
  if (crm1->next_retry.abs_value_us < crm2->next_retry.abs_value_us)
    return GNUNET_YES;
  return GNUNET_NO;
}

References GNUNET_TIME_Absolute::abs_value_us, GNUNET_NO, GNUNET_YES, and CadetReliableMessage::next_retry.

Referenced by data_sent_cb().

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GCCH_handle_local_data()

int GCCH_handle_local_data	(	struct CadetChannel *	ch,
		struct GNUNET_CADET_ClientChannelNumber	sender_ccn,
		const char *	buf,
		size_t	buf_len
	)

Handle data given by a client.

Check whether the client is allowed to send in this tunnel, save if channel is reliable and send an ACK to the client if there is still buffer space in the tunnel.

Parameters

ch	Channel.
sender_ccn	ccn of the sender
buf	payload to transmit.
buf_len	number of bytes in buf

Returns

GNUNET_OK if everything goes well, GNUNET_SYSERR in case of an error.

Definition at line 1770 of file gnunet-service-cadet_channel.c.

{
  struct CadetReliableMessage *crm;
 
  if (ch->pending_messages >= ch->max_pending_messages)
  {
    GNUNET_break (0);  /* Fails: #5370 */
    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 ack_to_owner;
 
    env =
      GNUNET_MQ_msg_extra (ld, buf_len, GNUNET_MESSAGE_TYPE_CADET_LOCAL_DATA);
    if ((NULL != ch->owner) &&
        (sender_ccn.channel_of_client == ch->owner->ccn.channel_of_client))
    {
      receiver = ch->dest;
      ack_to_owner = GNUNET_YES;
    }
    else if ((NULL != ch->dest) &&
             (sender_ccn.channel_of_client == ch->dest->ccn.channel_of_client))
    {
      receiver = ch->owner;
      ack_to_owner = GNUNET_NO;
    }
    else
    {
      GNUNET_free (env);
      GNUNET_break (0);
      return GNUNET_SYSERR;
    }
    GNUNET_assert (NULL != receiver);
    ld->ccn = receiver->ccn;
    GNUNET_memcpy (&ld[1], buf, buf_len);
    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;
  }
 
  /* Everything is correct, send the message. */
  crm = GNUNET_malloc (sizeof(*crm));
  crm->ch = ch;
  crm->data_message = GNUNET_malloc (
    sizeof(struct GNUNET_CADET_ChannelAppDataMessage) + buf_len);
  crm->data_message->header.size =
    htons (sizeof(struct GNUNET_CADET_ChannelAppDataMessage) + buf_len);
  crm->data_message->header.type =
    htons (GNUNET_MESSAGE_TYPE_CADET_CHANNEL_APP_DATA);
  ch->mid_send.mid = htonl (ntohl (ch->mid_send.mid) + 1);
  crm->data_message->mid = ch->mid_send;
  crm->data_message->ctn = ch->ctn;
  GNUNET_memcpy (&crm->data_message[1], buf, buf_len);
  GNUNET_CONTAINER_DLL_insert_tail (ch->head_sent, ch->tail_sent, crm);
  LOG (GNUNET_ERROR_TYPE_DEBUG,
       "Sending message %u from local client to %s with %lu bytes\n",
       ntohl (crm->data_message->mid.mid),
       GCCH_2s (ch),
       (unsigned long) 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,
                      &crm->data_message->ctn);
  GNUNET_assert (NULL == ch->retry_data_task);
  return GNUNET_OK;
}

References GNUNET_CADET_Channel::ccn, GNUNET_CADET_LocalData::ccn, ch, CadetReliableMessage::ch, GNUNET_CADET_ClientChannelNumber::channel_of_client, GNUNET_CADET_ChannelAppDataMessage::ctn, CadetReliableMessage::data_message, data_sent_cb(), env, CadetOutOfOrderMessage::env, GCCH_2s(), GCT_send(), GNUNET_assert, GNUNET_break, GNUNET_CONTAINER_DLL_insert_tail, GNUNET_ERROR_TYPE_DEBUG, GNUNET_free, GNUNET_malloc, GNUNET_memcpy, GNUNET_MESSAGE_TYPE_CADET_CHANNEL_APP_DATA, GNUNET_MESSAGE_TYPE_CADET_LOCAL_DATA, GNUNET_MQ_msg_extra, GNUNET_new, GNUNET_NO, GNUNET_OK, GNUNET_SCHEDULER_cancel(), GNUNET_SYSERR, GNUNET_YES, GSC_send_to_client(), GNUNET_CADET_ChannelAppDataMessage::header, LOG, ChannelMessageIdentifier::mid, GNUNET_CADET_ChannelAppDataMessage::mid, CadetReliableMessage::qe, receiver(), send_ack_to_client(), GNUNET_MessageHeader::size, and GNUNET_MessageHeader::type.

Referenced by handle_local_data().

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GCCH_handle_local_ack()

void GCCH_handle_local_ack	(	struct CadetChannel *	ch,
		struct GNUNET_CADET_ClientChannelNumber	client_ccn
	)

Handle ACK from client on local channel.

Means the client is ready for more data, see if we have any for it.

Parameters

ch	channel to destroy
client_ccn	ccn of the client sending the ack

Definition at line 1871 of file gnunet-service-cadet_channel.c.

{
  struct CadetChannelClient *ccc;
  struct CadetOutOfOrderMessage *com;
 
  if ((NULL != ch->owner) &&
      (ch->owner->ccn.channel_of_client == client_ccn.channel_of_client))
    ccc = ch->owner;
  else if ((NULL != ch->dest) &&
           (ch->dest->ccn.channel_of_client == client_ccn.channel_of_client))
    ccc = ch->dest;
  else
    GNUNET_assert (0);
  ccc->client_ready = GNUNET_YES;
  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 ((NULL != ch->owner) &&
        (ccc->ccn.channel_of_client == ch->owner->ccn.channel_of_client))
    {
      to_owner = GNUNET_NO;
    }
    else
    {
      GNUNET_assert ((NULL != ch->dest) && (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_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 */
  }
 
  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);
  send_channel_data_ack (ch);
  if (NULL != ccc->head_recv)
    return;
  if (GNUNET_NO == ch->destroy)
    return;
  GCT_send_channel_destroy (ch->t, ch->ctn);
  channel_destroy (ch);
}

References CadetChannelClient::c, GNUNET_CADET_Channel::ccn, CadetChannelClient::ccn, ch, channel_destroy(), GNUNET_CADET_ClientChannelNumber::channel_of_client, CadetChannelClient::client_ready, CadetOutOfOrderMessage::env, GCCH_2s(), GCT_send_channel_destroy(), GNUNET_assert, GNUNET_CONTAINER_DLL_remove, GNUNET_ERROR_TYPE_DEBUG, GNUNET_free, GNUNET_NO, GNUNET_YES, GSC_2s(), GSC_send_to_client(), CadetChannelClient::head_recv, LOG, ChannelMessageIdentifier::mid, CadetOutOfOrderMessage::mid, CadetChannelClient::num_recv, send_ack_to_client(), send_channel_data_ack(), and CadetChannelClient::tail_recv.

Referenced by handle_local_ack().

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GCCH_debug()

void GCCH_debug	(	struct CadetChannel *	ch,
		enum GNUNET_ErrorType	level
	)

Log channel info.

Parameters

ch	Channel.
level	Debug level to use.

Definition at line 1974 of file gnunet-service-cadet_channel.c.

{
#if ! defined(GNUNET_CULL_LOGGING)
  int do_log;
 
  do_log = GNUNET_get_log_call_status (level & (~GNUNET_ERROR_TYPE_BULK),
                                       "cadet-chn",
                                       __FILE__,
                                       __FUNCTION__,
                                       __LINE__);
  if (0 == do_log)
    return;
 
  if (NULL == ch)
  {
    LOG2 (level, "CHN *** DEBUG NULL CHANNEL ***\n");
    return;
  }
  LOG2 (level, "CHN %s:%X (%p)\n", GCT_2s (ch->t), ch->ctn.cn, ch);
  if (NULL != ch->owner)
  {
    LOG2 (level,
          "CHN origin %s ready %s local-id: %u\n",
          GSC_2s (ch->owner->c),
          ch->owner->client_ready ? "YES" : "NO",
          ntohl (ch->owner->ccn.channel_of_client));
  }
  if (NULL != ch->dest)
  {
    LOG2 (level,
          "CHN destination %s ready %s local-id: %u\n",
          GSC_2s (ch->dest->c),
          ch->dest->client_ready ? "YES" : "NO",
          ntohl (ch->dest->ccn.channel_of_client));
  }
  LOG2 (level,
        "CHN  Message IDs recv: %d (%llX), send: %d\n",
        ntohl (ch->mid_recv.mid),
        (unsigned long long) ch->mid_futures,
        ntohl (ch->mid_send.mid));
#endif
}

References GNUNET_CADET_Channel::ccn, ch, GNUNET_CADET_ClientChannelNumber::channel_of_client, GCT_2s(), GNUNET_ERROR_TYPE_BULK, GNUNET_get_log_call_status(), GSC_2s(), and LOG2.

Referenced by debug_channel().

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