summaryrefslogtreecommitdiffstats
path: root/src/sync-alarm.c
blob: 0fc7943b8ade47f13e36c48e065b8a664988b0c8 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
/*
 * (C) 2006-2007 by Pablo Neira Ayuso <pablo@netfilter.org>
 * 
 * This program 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.
 *
 * This program 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 this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#include "conntrackd.h"
#include "sync.h"
#include "network.h"
#include "alarm.h"
#include "cache.h"
#include "queue.h"

#include <stdlib.h>
#include <string.h>

struct cache_alarm {
	struct queue_node	qnode;
	struct alarm_block	alarm;
};

static void alarm_enqueue(struct cache_object *obj, int query);

static void refresher(struct alarm_block *a, void *data)
{
	struct cache_object *obj = data;

	add_alarm(a, 
		  random() % CONFIG(refresh) + 1,
		  ((random() % 5 + 1)  * 200000) - 1);

	alarm_enqueue(obj, NET_T_STATE_UPD);
}

static void cache_alarm_add(struct cache_object *obj, void *data)
{
	struct cache_alarm *ca = data;

	queue_node_init(&ca->qnode, Q_ELEM_OBJ);
	init_alarm(&ca->alarm, obj, refresher);
	add_alarm(&ca->alarm,
		  random() % CONFIG(refresh) + 1,
		  ((random() % 5 + 1)  * 200000) - 1);
}

static void cache_alarm_update(struct cache_object *obj, void *data)
{
	struct cache_alarm *ca = data;
	add_alarm(&ca->alarm, 
		  random() % CONFIG(refresh) + 1,
		  ((random() % 5 + 1)  * 200000) - 1);
}

static void cache_alarm_destroy(struct cache_object *obj, void *data)
{
	struct cache_alarm *ca = data;
	queue_del(&ca->qnode);
	del_alarm(&ca->alarm);
}

static struct cache_extra cache_alarm_extra = {
	.size 		= sizeof(struct cache_alarm),
	.add		= cache_alarm_add,
	.update		= cache_alarm_update,
	.destroy	= cache_alarm_destroy
};

static int alarm_recv(const struct nethdr *net)
{
	unsigned int exp_seq;

	/* 
	 * Ignore error messages: Although this message type is not ever
	 * generated in alarm mode, we don't want to crash the daemon 
	 * if someone nuts mixes ftfw and alarm.
	 */
	if (net->flags)
		return 1;

	/* 
	 * Multicast sequence tracking: we keep track of multicast messages
	 * although we don't do any explicit message recovery. So, why do
	 * we do sequence tracking? Just to let know the sysadmin.
	 *
	 * Let t be 1 < t < RefreshTime. To ensure consistency, conntrackd
	 * retransmit every t seconds a message with the state of a certain
	 * entry even if such entry did not change. This mechanism also
	 * provides passive resynchronization, in other words, there is
	 * no facility to request a full synchronization from new nodes that
	 * just joined the cluster, instead they just get resynchronized in
	 * RefreshTime seconds at worst case.
	 */
	nethdr_track_seq(net->seq, &exp_seq);

	return 0;
}

static void alarm_enqueue(struct cache_object *obj, int query)
{
	struct cache_alarm *ca =
		cache_get_extra(STATE(mode)->internal->data, obj);
	if (queue_add(STATE_SYNC(tx_queue), &ca->qnode))
		cache_object_get(obj);
}

static int tx_queue_xmit(struct queue_node *n, const void *data)
{
	struct nethdr *net;

	queue_del(n);

	switch(n->type) {
	case Q_ELEM_CTL:
		net = queue_node_data(n);
		nethdr_set_ctl(net);
		HDR_HOST2NETWORK(net);
		multichannel_send(STATE_SYNC(channel), net);
		queue_object_free((struct queue_object *)n);
		break;
	case Q_ELEM_OBJ: {
		struct cache_alarm *ca;
		struct cache_object *obj;
		int type;

		ca = (struct cache_alarm *)n;
		obj = cache_data_get_object(STATE(mode)->internal->data, ca);
		type = object_status_to_network_type(obj->status);
		net = BUILD_NETMSG(obj->ct, type);
		multichannel_send(STATE_SYNC(channel), net);
		cache_object_put(obj);
		break;
	}
	}
	return 0;
}

static void alarm_xmit(void)
{
	queue_iterate(STATE_SYNC(tx_queue), NULL, tx_queue_xmit);
}

struct sync_mode sync_alarm = {
	.internal_cache_flags	= NO_FEATURES,
	.external_cache_flags	= TIMER,
	.internal_cache_extra	= &cache_alarm_extra,
	.recv 			= alarm_recv,
	.enqueue		= alarm_enqueue,
	.xmit			= alarm_xmit,
};