1/*-
2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3 *
4 * Copyright (c) 2020 Alexander V. Chernikov
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 *    notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in the
13 *    documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25 * SUCH DAMAGE.
26 */
27
28/*
29 * This file contains code responsible for expiring temporal routes
30 * (typically, redirect-originated) from the route tables.
31 */
32
33#include <sys/cdefs.h>
34__FBSDID("$FreeBSD$");
35
36#include <sys/param.h>
37#include <sys/systm.h>
38#include <sys/socket.h>
39#include <sys/kernel.h>
40#include <sys/lock.h>
41#include <sys/ck.h>
42#include <sys/rmlock.h>
43#include <sys/callout.h>
44
45#include <net/if.h>
46#include <net/route.h>
47#include <net/route/route_ctl.h>
48#include <net/route/route_var.h>
49#include <net/vnet.h>
50
51/*
52 * Callback returning 1 for the expired routes.
53 * Updates time of the next nearest route expiration as a side effect.
54 */
55static int
56expire_route(const struct rtentry *rt, const struct nhop_object *nh, void *arg)
57{
58	time_t *next_callout;
59
60	if (rt->rt_expire == 0)
61		return (0);
62
63	if (rt->rt_expire <= time_uptime)
64		return (1);
65
66	next_callout = (time_t *)arg;
67
68	/*
69	 * Update next_callout to determine the next ts to
70	 * run the callback at.
71	 */
72	if (*next_callout == 0 || *next_callout > rt->rt_expire)
73		*next_callout = rt->rt_expire;
74
75	return (0);
76}
77
78/*
79 * Per-rnh callout function traversing the tree and deleting
80 * expired routes. Calculates next callout run by looking at
81 * the rt_expire time for the remaining temporal routes.
82 */
83static void
84expire_callout(void *arg)
85{
86	struct rib_head *rnh;
87	time_t next_expire;
88	int seconds;
89
90	rnh = (struct rib_head *)arg;
91
92	CURVNET_SET(rnh->rib_vnet);
93	next_expire = 0;
94
95	rib_walk_del(rnh->rib_fibnum, rnh->rib_family, expire_route,
96	    (void *)&next_expire, 1);
97
98	RIB_WLOCK(rnh);
99	if (next_expire > 0) {
100		seconds = (next_expire - time_uptime);
101		if (seconds < 0)
102			seconds = 0;
103		callout_reset_sbt(&rnh->expire_callout, SBT_1S * seconds,
104		    SBT_1MS * 500, expire_callout, rnh, 0);
105		rnh->next_expire = next_expire;
106	} else {
107		/*
108		 * Before resetting next_expire, check that tmproutes_update()
109		 * has not kicked in and scheduled another invocation.
110		 */
111		if (callout_pending(&rnh->expire_callout) == 0)
112			rnh->next_expire = 0;
113	}
114	RIB_WUNLOCK(rnh);
115	CURVNET_RESTORE();
116}
117
118/*
119 * Function responsible for updating the time of the next calllout
120 * w.r.t. new temporal routes insertion.
121 *
122 * Called by the routing code upon adding new temporal route
123 * to the tree. RIB_WLOCK must be held.
124 */
125void
126tmproutes_update(struct rib_head *rnh, struct rtentry *rt)
127{
128	int seconds;
129
130	RIB_WLOCK_ASSERT(rnh);
131
132	if (rnh->next_expire == 0 || rnh->next_expire > rt->rt_expire) {
133		/*
134		 * Callback is not scheduled, is executing,
135		 * or is scheduled for a later time than we need.
136		 *
137		 * Schedule the one for the current @rt expiration time.
138		 */
139		seconds = (rt->rt_expire - time_uptime);
140		if (seconds < 0)
141			seconds = 0;
142		callout_reset_sbt(&rnh->expire_callout, SBT_1S * seconds,
143		    SBT_1MS * 500, expire_callout, rnh, 0);
144
145		rnh->next_expire = rt->rt_expire;
146	}
147}
148
149void
150tmproutes_init(struct rib_head *rh)
151{
152
153	callout_init(&rh->expire_callout, 1);
154}
155
156void
157tmproutes_destroy(struct rib_head *rh)
158{
159
160	callout_drain(&rh->expire_callout);
161}
162