diff options
author | james <james@e7ae566f-a301-0410-adde-c780ea21d3b5> | 2005-09-26 05:28:27 +0000 |
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committer | james <james@e7ae566f-a301-0410-adde-c780ea21d3b5> | 2005-09-26 05:28:27 +0000 |
commit | 6fbf66fad3367b24fd6743bcd50254902fd9c8d5 (patch) | |
tree | 9802876e3771744eead18917bb47ff6e90ac39f5 /schedule.h | |
download | openvpn-6fbf66fad3367b24fd6743bcd50254902fd9c8d5.tar.xz |
This is the start of the BETA21 branch.
It includes the --topology feature, and
TAP-Win32 driver changes to allow
non-admin access.
git-svn-id: http://svn.openvpn.net/projects/openvpn/branches/BETA21/openvpn@580 e7ae566f-a301-0410-adde-c780ea21d3b5
Diffstat (limited to 'schedule.h')
-rw-r--r-- | schedule.h | 140 |
1 files changed, 140 insertions, 0 deletions
diff --git a/schedule.h b/schedule.h new file mode 100644 index 0000000..4e0ae74 --- /dev/null +++ b/schedule.h @@ -0,0 +1,140 @@ +/* + * OpenVPN -- An application to securely tunnel IP networks + * over a single TCP/UDP port, with support for SSL/TLS-based + * session authentication and key exchange, + * packet encryption, packet authentication, and + * packet compression. + * + * Copyright (C) 2002-2005 OpenVPN Solutions LLC <info@openvpn.net> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 + * as published by the Free Software Foundation. + * + * 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 (see the file COPYING included with this + * distribution); if not, write to the Free Software Foundation, Inc., + * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + */ + +#ifndef SCHEDULE_H +#define SCHEDULE_H + +/* + * This code implements an efficient scheduler using + * a random treap binary tree. + * + * The scheduler is used by the server executive to + * keep track of which instances need service at a + * known time in the future. Instances need to + * schedule events for things such as sending + * a ping or scheduling a TLS renegotiation. + */ + +#if P2MP_SERVER + +/* define to enable a special test mode */ +/*#define SCHEDULE_TEST*/ + +#include "otime.h" +#include "thread.h" +#include "error.h" + +struct schedule_entry +{ + struct timeval tv; /* wakeup time */ + unsigned int pri; /* random treap priority */ + struct schedule_entry *parent; /* treap (btree) links */ + struct schedule_entry *lt; + struct schedule_entry *gt; +}; + +struct schedule +{ + MUTEX_DEFINE (mutex); + struct schedule_entry *earliest_wakeup; /* cached earliest wakeup */ + struct schedule_entry *root; /* the root of the treap (btree) */ +}; + +/* Public functions */ + +struct schedule *schedule_init (void); +void schedule_free (struct schedule *s); +void schedule_remove_entry (struct schedule *s, struct schedule_entry *e); + +#ifdef SCHEDULE_TEST +void schedule_test (void); +#endif + +/* Private Functions */ + +/* is node already in tree? */ +#define IN_TREE(e) ((e)->pri) + +struct schedule_entry *schedule_find_least (struct schedule_entry *e); +void schedule_add_modify (struct schedule *s, struct schedule_entry *e); +void schedule_remove_node (struct schedule *s, struct schedule_entry *e); + +/* Public inline functions */ + +/* + * Add a struct schedule_entry (whose storage is managed by + * caller) to the btree. tv signifies the wakeup time for + * a future event. sigma is a time interval measured + * in microseconds -- the event window being represented + * starts at (tv - sigma) and ends at (tv + sigma). + * Event signaling can occur anywere within this interval. + * Making the interval larger makes the scheduler more efficient, + * while making it smaller results in more precise scheduling. + * The caller should treat the passed struct schedule_entry as + * an opaque object. + */ +static inline void +schedule_add_entry (struct schedule *s, + struct schedule_entry *e, + const struct timeval *tv, + unsigned int sigma) +{ + mutex_lock (&s->mutex); + if (!IN_TREE (e) || !sigma || !tv_within_sigma (tv, &e->tv, sigma)) + { + e->tv = *tv; + schedule_add_modify (s, e); + s->earliest_wakeup = NULL; /* invalidate cache */ + } + mutex_unlock (&s->mutex); +} + +/* + * Return the node with the earliest wakeup time. If two + * nodes have the exact same wakeup time, select based on + * the random priority assigned to each node (the priority + * is randomized every time an entry is re-added). + */ +static inline struct schedule_entry * +schedule_get_earliest_wakeup (struct schedule *s, + struct timeval *wakeup) +{ + struct schedule_entry *ret; + + mutex_lock (&s->mutex); + + /* cache result */ + if (!s->earliest_wakeup) + s->earliest_wakeup = schedule_find_least (s->root); + ret = s->earliest_wakeup; + if (ret) + *wakeup = ret->tv; + + mutex_unlock (&s->mutex); + + return ret; +} + +#endif +#endif |