/*
This file is part of GNUnet.
- (C) 2010 Christian Grothoff (and other contributing authors)
+ Copyright (C) 2010 GNUnet e.V.
GNUnet is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published
- by the Free Software Foundation; either version 2, or (at your
+ by the Free Software Foundation; either version 3, or (at your
option) any later version.
GNUnet is distributed in the hope that it will be useful, but
You should have received a copy of the GNU General Public License
along with GNUnet; see the file COPYING. If not, write to the
- Free Software Foundation, Inc., 59 Temple Place - Suite 330,
- Boston, MA 02111-1307, USA.
+ Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+ Boston, MA 02110-1301, USA.
*/
/**
* @file util/server_nc.c
* @brief convenience functions for transmission of
- * a notification stream
+ * a notification stream
* @author Christian Grothoff
*/
#include "platform.h"
-#include "gnunet_common.h"
-#include "gnunet_connection_lib.h"
-#include "gnunet_scheduler_lib.h"
-#include "gnunet_server_lib.h"
-#include "gnunet_time_lib.h"
+#include "gnunet_util_lib.h"
+#define LOG(kind,...) GNUNET_log_from (kind, "util-server-nc", __VA_ARGS__)
+
+/**
+ * Entry in list of messages pending to be transmitted.
+ */
struct PendingMessageList
{
+ /**
+ * This is a doubly-linked list.
+ */
struct PendingMessageList *next;
+ /**
+ * This is a doubly-linked list.
+ */
+ struct PendingMessageList *prev;
+
+ /**
+ * Message to transmit (allocated at the end of this
+ * struct, do not free)
+ */
const struct GNUNET_MessageHeader *msg;
+ /**
+ * Can this message be dropped?
+ */
int can_drop;
};
+/**
+ * Lists of clients we manage for notifications.
+ */
struct ClientList
{
+ /**
+ * This is a doubly linked list.
+ */
struct ClientList *next;
+ /**
+ * This is a doubly linked list.
+ */
+ struct ClientList *prev;
+
+ /**
+ * Overall context this client belongs to.
+ */
+ struct GNUNET_SERVER_NotificationContext *nc;
+
+ /**
+ * Handle to the client.
+ */
struct GNUNET_SERVER_Client *client;
- struct GNUNET_CONNECTION_TransmitHandle *th;
+ /**
+ * Handle for pending transmission request to the client (or NULL).
+ */
+ struct GNUNET_SERVER_TransmitHandle *th;
+
+ /**
+ * Head of linked list of requests queued for transmission.
+ */
+ struct PendingMessageList *pending_head;
- struct PendingMessageList *pending;
+ /**
+ * Tail of linked list of requests queued for transmission.
+ */
+ struct PendingMessageList *pending_tail;
+ /**
+ * Number of messages currently in the list.
+ */
unsigned int num_pending;
};
/**
- * The notification context is the key datastructure for a conveniance
+ * The notification context is the key datastructure for a convenience
* API used for transmission of notifications to the client until the
* client disconnects (or the notification context is destroyed, in
* which case we disconnect these clients). Essentially, all
struct GNUNET_SERVER_NotificationContext
{
+ /**
+ * Server we do notifications for.
+ */
struct GNUNET_SERVER_Handle *server;
- struct ClientList *clients;
+ /**
+ * Head of list of clients receiving notifications.
+ */
+ struct ClientList *clients_head;
+ /**
+ * Tail of list of clients receiving notifications.
+ */
+ struct ClientList *clients_tail;
+
+ /**
+ * Maximum number of optional messages to queue per client.
+ */
unsigned int queue_length;
};
+/**
+ * Client has disconnected, clean up.
+ *
+ * @param cls our `struct GNUNET_SERVER_NotificationContext *`
+ * @param client handle of client that disconnected
+ */
static void
handle_client_disconnect (void *cls,
- struct GNUNET_SERVER_Client *client)
+ struct GNUNET_SERVER_Client *client)
{
struct GNUNET_SERVER_NotificationContext *nc = cls;
struct ClientList *pos;
- struct ClientList *prev;
struct PendingMessageList *pml;
- prev = NULL;
- pos = nc->clients;
- while (NULL != pos)
- {
- if (pos->client == client)
- break;
- prev = pos;
- pos = pos->next;
- }
- if (pos == NULL)
+ if (NULL == client)
+ {
+ nc->server = NULL;
return;
- if (prev == NULL)
- nc->clients = pos->next;
- else
- prev->next = pos->next;
- while (NULL != (pml = pos->pending))
- {
- pos->pending = pml->next;
- GNUNET_free (pml);
- }
+ }
+ for (pos = nc->clients_head; NULL != pos; pos = pos->next)
+ if (pos->client == client)
+ break;
+ if (NULL == pos)
+ return;
+ LOG (GNUNET_ERROR_TYPE_DEBUG,
+ "Client disconnected, cleaning up %u messages in NC queue\n",
+ pos->num_pending);
+ GNUNET_CONTAINER_DLL_remove (nc->clients_head,
+ nc->clients_tail,
+ pos);
+ while (NULL != (pml = pos->pending_head))
+ {
+ GNUNET_CONTAINER_DLL_remove (pos->pending_head,
+ pos->pending_tail,
+ pml);
+ GNUNET_free (pml);
+ pos->num_pending--;
+ }
+ if (NULL != pos->th)
+ {
+ GNUNET_SERVER_notify_transmit_ready_cancel (pos->th);
+ pos->th = NULL;
+ }
+ GNUNET_SERVER_client_drop (client);
+ GNUNET_assert (0 == pos->num_pending);
GNUNET_free (pos);
}
* @param server server for which this function creates the context
* @param queue_length maximum number of messages to keep in
* the notification queue; optional messages are dropped
- * it the queue gets longer than this number of messages
+ * if the queue gets longer than this number of messages
* @return handle to the notification context
*/
struct GNUNET_SERVER_NotificationContext *
GNUNET_SERVER_notification_context_create (struct GNUNET_SERVER_Handle *server,
- unsigned int queue_length)
+ unsigned int queue_length)
{
struct GNUNET_SERVER_NotificationContext *ret;
- ret = GNUNET_malloc (sizeof (struct GNUNET_SERVER_NotificationContext));
+ ret = GNUNET_new (struct GNUNET_SERVER_NotificationContext);
ret->server = server;
ret->queue_length = queue_length;
GNUNET_SERVER_disconnect_notify (server,
- &handle_client_disconnect,
- ret);
+ &handle_client_disconnect,
+ ret);
return ret;
}
struct ClientList *pos;
struct PendingMessageList *pml;
- while (NULL != (pos = nc->clients))
+ while (NULL != (pos = nc->clients_head))
+ {
+ GNUNET_CONTAINER_DLL_remove (nc->clients_head,
+ nc->clients_tail,
+ pos);
+ if (NULL != pos->th)
{
- nc->clients = pos->next;
- GNUNET_SERVER_receive_done (pos->client, GNUNET_NO);
- GNUNET_SERVER_client_drop (pos->client);
- while (NULL != (pml = pos->pending))
- {
- pos->pending = pml->next;
- GNUNET_free (pml);
- }
- GNUNET_free (pos);
+ GNUNET_SERVER_notify_transmit_ready_cancel (pos->th);
+ pos->th = NULL;
}
- GNUNET_SERVER_disconnect_notify_cancel (nc->server,
- &handle_client_disconnect,
- nc);
+ GNUNET_SERVER_client_drop (pos->client);
+ while (NULL != (pml = pos->pending_head))
+ {
+ GNUNET_CONTAINER_DLL_remove (pos->pending_head,
+ pos->pending_tail,
+ pml);
+ GNUNET_free (pml);
+ pos->num_pending--;
+ }
+ GNUNET_assert (0 == pos->num_pending);
+ GNUNET_free (pos);
+ }
+ if (NULL != nc->server)
+ GNUNET_SERVER_disconnect_notify_cancel (nc->server,
+ &handle_client_disconnect,
+ nc);
GNUNET_free (nc);
}
*/
void
GNUNET_SERVER_notification_context_add (struct GNUNET_SERVER_NotificationContext *nc,
- struct GNUNET_SERVER_Client *client)
+ struct GNUNET_SERVER_Client *client)
+{
+ struct ClientList *cl;
+
+ for (cl = nc->clients_head; NULL != cl; cl = cl->next)
+ if (cl->client == client)
+ return; /* already present */
+ cl = GNUNET_new (struct ClientList);
+ GNUNET_CONTAINER_DLL_insert (nc->clients_head,
+ nc->clients_tail,
+ cl);
+ cl->nc = nc;
+ cl->client = client;
+ GNUNET_SERVER_client_keep (client);
+}
+
+
+/**
+ * Function called to notify a client about the socket begin ready to
+ * queue more data. @a buf will be NULL and @a size zero if the socket
+ * was closed for writing in the meantime.
+ *
+ * @param cls the `struct ClientList *`
+ * @param size number of bytes available in @a buf
+ * @param buf where the callee should write the message
+ * @return number of bytes written to buf
+ */
+static size_t
+transmit_message (void *cls,
+ size_t size,
+ void *buf)
+{
+ struct ClientList *cl = cls;
+ char *cbuf = buf;
+ struct PendingMessageList *pml;
+ uint16_t msize;
+ size_t ret;
+
+ cl->th = NULL;
+ if (NULL == buf)
+ {
+ /* 'cl' should be freed via disconnect notification shortly */
+ LOG (GNUNET_ERROR_TYPE_DEBUG,
+ "Failed to transmit message from NC queue to client\n");
+ return 0;
+ }
+ ret = 0;
+ while (NULL != (pml = cl->pending_head))
+ {
+ msize = ntohs (pml->msg->size);
+ if (size < msize)
+ break;
+ GNUNET_CONTAINER_DLL_remove (cl->pending_head,
+ cl->pending_tail,
+ pml);
+ LOG (GNUNET_ERROR_TYPE_DEBUG,
+ "Copying message of type %u and size %u from pending queue to transmission buffer\n",
+ ntohs (pml->msg->type),
+ msize);
+ GNUNET_memcpy (&cbuf[ret], pml->msg, msize);
+ ret += msize;
+ size -= msize;
+ GNUNET_free (pml);
+ cl->num_pending--;
+ }
+ if (NULL != pml)
+ {
+ LOG (GNUNET_ERROR_TYPE_DEBUG,
+ "Have %u messages left in NC queue, will try transmission again\n",
+ cl->num_pending);
+ cl->th =
+ GNUNET_SERVER_notify_transmit_ready (cl->client,
+ ntohs (pml->msg->size),
+ GNUNET_TIME_UNIT_FOREVER_REL,
+ &transmit_message, cl);
+ }
+ else
+ {
+ GNUNET_assert (0 == cl->num_pending);
+ }
+ return ret;
+}
+
+
+/**
+ * Send a message to a particular client.
+ *
+ * @param nc context to modify
+ * @param client client to transmit to
+ * @param msg message to send
+ * @param can_drop can this message be dropped due to queue length limitations
+ */
+static void
+do_unicast (struct GNUNET_SERVER_NotificationContext *nc,
+ struct ClientList *client,
+ const struct GNUNET_MessageHeader *msg,
+ int can_drop)
{
+ struct PendingMessageList *pml;
+ uint16_t size;
+
+ if ( (client->num_pending > nc->queue_length) &&
+ (GNUNET_YES == can_drop) )
+ {
+ LOG (GNUNET_ERROR_TYPE_INFO,
+ "Dropping message of type %u and size %u due to full queue (%u entries)\n",
+ ntohs (msg->type), ntohs (msg->size), (unsigned int) nc->queue_length);
+ return; /* drop! */
+ }
+ if (client->num_pending > nc->queue_length)
+ {
+ /* FIXME: consider checking for other messages in the
+ * queue that are 'droppable' */
+ }
+ client->num_pending++;
+ size = ntohs (msg->size);
+ pml = GNUNET_malloc (sizeof (struct PendingMessageList) + size);
+ pml->msg = (const struct GNUNET_MessageHeader *) &pml[1];
+ pml->can_drop = can_drop;
+ LOG (GNUNET_ERROR_TYPE_DEBUG,
+ "Adding message of type %u and size %u to pending queue (which has %u entries)\n",
+ ntohs (msg->type),
+ ntohs (msg->size),
+ (unsigned int) nc->queue_length);
+ GNUNET_memcpy (&pml[1], msg, size);
+ /* append */
+ GNUNET_CONTAINER_DLL_insert_tail (client->pending_head,
+ client->pending_tail,
+ pml);
+ if (NULL == client->th)
+ client->th =
+ GNUNET_SERVER_notify_transmit_ready (client->client,
+ ntohs (client->pending_head->
+ msg->size),
+ GNUNET_TIME_UNIT_FOREVER_REL,
+ &transmit_message, client);
}
*/
void
GNUNET_SERVER_notification_context_unicast (struct GNUNET_SERVER_NotificationContext *nc,
- struct GNUNET_SERVER_Client *client,
- const struct GNUNET_MessageHeader *msg,
- int can_drop)
+ struct GNUNET_SERVER_Client *client,
+ const struct GNUNET_MessageHeader *msg,
+ int can_drop)
{
+ struct ClientList *pos;
+
+ for (pos = nc->clients_head; NULL != pos; pos = pos->next)
+ if (pos->client == client)
+ break;
+ GNUNET_assert (NULL != pos);
+ do_unicast (nc, pos, msg, can_drop);
}
* @param can_drop can this message be dropped due to queue length limitations
*/
void
-GNUNET_SERVER_notification_context_broadcast (struct GNUNET_SERVER_NotificationContext *nc,
- const struct GNUNET_MessageHeader *msg,
- int can_drop)
+GNUNET_SERVER_notification_context_broadcast (struct
+ GNUNET_SERVER_NotificationContext *nc,
+ const struct GNUNET_MessageHeader *msg,
+ int can_drop)
{
+ struct ClientList *pos;
+
+ for (pos = nc->clients_head; NULL != pos; pos = pos->next)
+ do_unicast (nc, pos, msg, can_drop);
}
+/**
+ * Return active number of subscribers in this context.
+ *
+ * @param nc context to query
+ * @return number of current subscribers
+ */
+unsigned int
+GNUNET_SERVER_notification_context_get_size (struct GNUNET_SERVER_NotificationContext *nc)
+{
+ unsigned int num;
+ struct ClientList *pos;
+
+ num = 0;
+ for (pos = nc->clients_head; NULL != pos; pos = pos->next)
+ num++;
+ return num;
+}
+
/* end of server_nc.c */