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/*
* $Id: alive.c 13777 2007-05-29 00:23:11Z cbiere $
*
* Copyright (c) 2002-2003, Raphael Manfredi
*
*----------------------------------------------------------------------
* This file is part of gtk-gnutella.
*
* gtk-gnutella 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 of the License, or
* (at your option) any later version.
*
* gtk-gnutella is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with gtk-gnutella; if not, write to the Free Software
* Foundation, Inc.:
* 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*----------------------------------------------------------------------
*/
/**
* @ingroup core
* @file
*
* Alive status checking ping/pongs.
*
* @author Raphael Manfredi
* @date 2002-2003
*/
#include "common.h"
RCSID("$Id: alive.c 13777 2007-05-29 00:23:11Z cbiere $")
#include "alive.h"
#include "nodes.h"
#include "guid.h"
#include "gmsg.h"
#include "pmsg.h"
#include "mq.h"
#include "pcache.h"
#include "lib/atoms.h"
#include "lib/tm.h"
#include "lib/walloc.h"
#include "if/gnet_property_priv.h"
#include "lib/override.h" /* Must be the last header included */
#define INFINITY 0xffffffff
/**
* Structure used to keep track of the alive pings we sent, and stats.
*/
struct alive {
struct gnutella_node *node;
GSList *pings; /**< Pings we sent (struct alive_ping) */
gint count; /**< Amount of pings in list */
gint maxcount; /**< Maximum amount of pings we remember */
guint32 min_rt; /**< Minimum roundtrip time (ms) */
guint32 max_rt; /**< Maximim roundtrip time (ms) */
guint32 avg_rt; /**< Average (EMA) roundtrip time (ms) */
guint32 last_rt; /**< Last roundtrip time (ms) */
};
struct alive_ping {
const gchar *muid; /**< The GUID of the message */
tm_t sent; /**< Time at which we sent the message */
};
static void alive_trim_upto(struct alive *a, GSList *item);
/**
* Create an alive_ping, with proper message ID.
*/
static struct alive_ping *
ap_make(gchar *muid)
{
struct alive_ping *ap;
ap = walloc(sizeof *ap);
ap->muid = atom_guid_get(muid);
tm_now_exact(&ap->sent);
return ap;
}
/**
* Free an alive_ping.
*/
static void
ap_free(struct alive_ping *ap)
{
atom_guid_free(ap->muid);
wfree(ap, sizeof *ap);
}
/**
* Create the alive structure.
* Returned as an opaque pointer.
*/
gpointer
alive_make(struct gnutella_node *n, gint max)
{
struct alive *a;
a = g_malloc0(sizeof *a);
a->node = n;
a->maxcount = max;
a->min_rt = INFINITY;
return a;
}
/**
* Dispose the alive structure.
*/
void
alive_free(gpointer obj)
{
struct alive *a = obj;
GSList *sl;
for (sl = a->pings; sl; sl = g_slist_next(sl))
ap_free(sl->data);
g_slist_free(a->pings);
G_FREE_NULL(a);
}
/**
* Remove and free specified "alive ping" list entry.
*/
static void
alive_remove_link(struct alive *a, GSList *item)
{
g_assert(a->count > 0);
g_assert(a->pings != NULL);
a->pings = g_slist_remove_link(a->pings, item);
a->count--;
ap_free(item->data);
g_slist_free_1(item);
}
/**
* Drop alive ping record when message is dropped.
*/
static void
alive_ping_drop(struct alive *a, const gchar *muid)
{
GSList *sl;
for (sl = a->pings; sl; sl = g_slist_next(sl)) {
struct alive_ping *ap = sl->data;
if (guid_eq(ap->muid, muid)) { /* Found it! */
alive_remove_link(a, sl);
return;
}
}
}
/**
* Test whether an alive ping can be sent.
* We send only the LATEST registered one.
*/
static gboolean
alive_ping_can_send(pmsg_t *mb, const mqueue_t *q)
{
const gnutella_node_t *n = mq_node(q);
struct alive *a = n->alive_pings;
gchar *muid = pmsg_start(mb);
g_assert(gnutella_header_get_function(muid) == GTA_MSG_INIT);
g_assert(a->count == 0 || a->pings != NULL);
/*
* We can send the message only if it's the latest in the list,
* i.e. the latest one we enqueued.
*/
if (a->count) {
const GSList *l = g_slist_last(a->pings);
const struct alive_ping *ap = l->data;
if (guid_eq(ap->muid, muid)) /* It's the latest one */
return TRUE; /* We can send it */
}
/*
* We're going to drop this alive ping: remove it from the list.
*/
alive_ping_drop(a, muid);
if (GNET_PROPERTY(dbg) > 1)
printf("ALIVE node %s (%s) dropped old alive ping %s, %d remain\n",
node_addr(a->node), node_vendor(a->node),
guid_hex_str(muid), a->count);
return FALSE; /* Don't send message */
}
/**
* Free routine for extended "alive ping" message block.
*/
static void
alive_pmsg_free(pmsg_t *mb, gpointer arg)
{
struct gnutella_node *n = arg;
g_assert(pmsg_is_extended(mb));
if (pmsg_was_sent(mb)) {
n->n_ping_sent++;
if (GNET_PROPERTY(dbg) > 1)
printf("ALIVE sent ping %s to node %s (%s)\n",
guid_hex_str(pmsg_start(mb)), node_addr(n), node_vendor(n));
} else {
gchar *muid = pmsg_start(mb);
struct alive *a = (struct alive *) n->alive_pings;
g_assert(a->node == n);
alive_ping_drop(a, muid);
}
}
/**
* Send new "alive" ping to node.
*
* @return TRUE if we sent it, FALSE if there are too many ACK-pending pings.
*/
gboolean
alive_send_ping(gpointer obj)
{
struct alive *a = (struct alive *) obj;
gchar muid[GUID_RAW_SIZE];
struct alive_ping *ap;
gnutella_msg_init_t *m;
guint32 size;
pmsg_t *mb;
g_assert(a->count == 0 || a->pings != NULL);
if (a->count >= a->maxcount)
return FALSE;
guid_ping_muid(muid);
ap = ap_make(muid);
a->count++;
a->pings = g_slist_append(a->pings, ap);
a->node->last_alive_ping = tm_time();
/*
* Build ping message and attach a pre-sender callback, as well as
* a free routine to see whether the message is sent.
*/
m = build_ping_msg(muid, 1, FALSE, &size);
g_assert(size == sizeof(*m)); /* No trailing GGEP extension */
mb = gmsg_to_ctrl_pmsg_extend(m, size, alive_pmsg_free, a->node);
pmsg_set_check(mb, alive_ping_can_send);
gmsg_mb_sendto_one(a->node, mb);
return TRUE;
}
/**
* Acknowledge alive_ping `ap', and update roundtrip statistics in `a'.
*/
static void
ap_ack(const struct alive_ping *ap, struct alive *a)
{
GTimeVal now;
gint delay; /**< Between sending and reception, in ms */
tm_now_exact(&now);
delay = (gint) ((now.tv_sec - ap->sent.tv_sec) * 1000 +
(now.tv_usec - ap->sent.tv_usec) / 1000);
a->last_rt = delay;
/*
* Update min-max roundtrips.
*/
if (delay < (gint) a->min_rt) {
if (a->min_rt == INFINITY)
a->avg_rt = delay; /* First time */
a->min_rt = delay;
}
if (delay > (gint) a->max_rt)
a->max_rt = delay;
/*
* Update average roundtrip time, using an EMA with smoothing sm=1/4.
* This corresponds to a moving average of n=7 terms: sm = 2/(n+1).
*/
a->avg_rt += (delay >> 2) - (a->avg_rt >> 2);
if (GNET_PROPERTY(dbg) > 4)
printf("ALIVE node %s (%s) "
"delay=%dms min=%dms, max=%dms, agv=%dms [%d queued]\n",
node_addr(a->node), node_vendor(a->node),
a->last_rt, a->min_rt, a->max_rt, a->avg_rt, a->count);
}
/**
* Trim list of pings upto the specified linkable `item', included.
*/
static void
alive_trim_upto(struct alive *a, GSList *item)
{
GSList *sl;
gboolean found = FALSE;
g_assert(a->count && a->pings != NULL);
for (sl = a->pings; sl && !found; sl = a->pings) {
found = sl == item;
alive_remove_link(a, sl);
}
g_assert(found); /* Must have found the item */
g_assert(a->count >= 0);
}
/**
* Got a pong that could be an acknowledge to one of our alive pings.
*
* @return TRUE if it was indeed an ACK for a ping we sent.
*/
gboolean
alive_ack_ping(gpointer obj, const gchar *muid)
{
struct alive *a = obj;
GSList *sl;
g_assert(a->count == 0 || a->pings != NULL);
for (sl = a->pings; sl; sl = g_slist_next(sl)) {
const struct alive_ping *ap = sl->data;
if (guid_eq(ap->muid, muid)) { /* Found it! */
if (GNET_PROPERTY(dbg) > 1)
printf("ALIVE got alive pong %s from %s (%s)\n",
guid_hex_str(muid), node_addr(a->node),
node_vendor(a->node));
ap_ack(ap, a);
alive_trim_upto(a, sl);
return TRUE;
}
}
return FALSE; /* Was a true regular "connectible" pong */
}
/**
* Got a ping with TTL=0, that some servents decided to use when
* replying to an alive ping.
*/
void
alive_ack_first(gpointer obj, const gchar *muid)
{
struct alive *a = obj;
struct alive_ping *ap;
GSList *sl;
g_assert(a->count == 0 || a->pings != NULL);
/*
* Maybe they're reusing the same MUID we used for our "alive ping"?
*/
if (alive_ack_ping(obj, muid))
return;
/*
* Assume they're replying to the first ping we sent, ignore otherwise.
*/
sl = a->pings; /* First ping we sent, chronologically */
if (NULL == sl)
return;
ap = sl->data;
if (GNET_PROPERTY(dbg) > 1)
printf("ALIVE TTL=0 ping from %s (%s), assuming it acks %s\n",
node_addr(a->node), node_vendor(a->node), guid_hex_str(ap->muid));
ap_ack(ap, a);
alive_remove_link(a, sl);
}
/**
* @returns the average/last ping/pong roundtrip time into supplied pointers.
* Values are expressed in milliseconds.
*/
void
alive_get_roundtrip_ms(gconstpointer obj, guint32 *avg, guint32 *last)
{
const struct alive *a = obj;
g_assert(NULL != obj);
if (avg) *avg = a->avg_rt;
if (last) *last = a->last_rt;
}
/* vi: set ts=4 sw=4 cindent: */
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