1/*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright (c) 2022 Alexander V. Chernikov <melifaro@FreeBSD.org>
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#include <sys/types.h>
29#include <sys/ck.h>
30#include <sys/epoch.h>
31#include <sys/kernel.h>
32#include <sys/malloc.h>
33#include <sys/socket.h>
34
35#include <net/route.h>
36#include <net/route/route_ctl.h>
37#include <netlink/netlink.h>
38#include <netlink/netlink_ctl.h>
39#include <netlink/netlink_route.h>
40#include <netlink/route/route_var.h>
41
42#define	DEBUG_MOD_NAME	nl_route_core
43#define	DEBUG_MAX_LEVEL	LOG_DEBUG3
44#include <netlink/netlink_debug.h>
45_DECLARE_DEBUG(LOG_INFO);
46
47#define	HANDLER_MAX_NUM	(NL_RTM_MAX + 10)
48static const struct rtnl_cmd_handler *rtnl_handler[HANDLER_MAX_NUM] = {};
49
50bool
51rtnl_register_messages(const struct rtnl_cmd_handler *handlers, int count)
52{
53	for (int i = 0; i < count; i++) {
54		if (handlers[i].cmd >= HANDLER_MAX_NUM)
55			return (false);
56		MPASS(rtnl_handler[handlers[i].cmd] == NULL);
57	}
58	for (int i = 0; i < count; i++)
59		rtnl_handler[handlers[i].cmd] = &handlers[i];
60	return (true);
61}
62
63/*
64 * Handler called by netlink subsystem when matching netlink message is received
65 */
66static int
67rtnl_handle_message(struct nlmsghdr *hdr, struct nl_pstate *npt)
68{
69	const struct rtnl_cmd_handler *cmd;
70	struct epoch_tracker et;
71	struct nlpcb *nlp = npt->nlp;
72	int error = 0;
73
74	if (__predict_false(hdr->nlmsg_type >= HANDLER_MAX_NUM)) {
75		NLMSG_REPORT_ERR_MSG(npt, "unknown message type: %d", hdr->nlmsg_type);
76		return (ENOTSUP);
77	}
78
79	cmd = rtnl_handler[hdr->nlmsg_type];
80	if (__predict_false(cmd == NULL)) {
81		NLMSG_REPORT_ERR_MSG(npt, "unknown message type: %d", hdr->nlmsg_type);
82		return (ENOTSUP);
83	}
84
85	NLP_LOG(LOG_DEBUG2, nlp, "received msg %s(%d) len %d", cmd->name,
86	    hdr->nlmsg_type, hdr->nlmsg_len);
87
88	if (cmd->priv != 0 && !nlp_has_priv(nlp, cmd->priv)) {
89		NLP_LOG(LOG_DEBUG2, nlp, "priv %d check failed for msg %s", cmd->priv, cmd->name);
90		return (EPERM);
91	} else if (cmd->priv != 0)
92		NLP_LOG(LOG_DEBUG3, nlp, "priv %d check passed for msg %s", cmd->priv, cmd->name);
93
94	if (!nlp_unconstrained_vnet(nlp) && (cmd->flags & RTNL_F_ALLOW_NONVNET_JAIL) == 0) {
95		NLP_LOG(LOG_DEBUG2, nlp, "jail check failed for msg %s", cmd->name);
96		return (EPERM);
97	}
98
99	bool need_epoch = !(cmd->flags & RTNL_F_NOEPOCH);
100
101	if (need_epoch)
102		NET_EPOCH_ENTER(et);
103	error = cmd->cb(hdr, nlp, npt);
104	if (need_epoch)
105		NET_EPOCH_EXIT(et);
106
107	NLP_LOG(LOG_DEBUG3, nlp, "message %s -> error %d", cmd->name, error);
108
109	return (error);
110}
111
112static struct rtbridge nlbridge = {
113	.route_f = rtnl_handle_route_event,
114	.ifmsg_f = rtnl_handle_ifnet_event,
115};
116static struct rtbridge *nlbridge_orig_p;
117
118static void
119rtnl_load(void *u __unused)
120{
121	NL_LOG(LOG_DEBUG2, "rtnl loading");
122	nlbridge_orig_p = netlink_callback_p;
123	netlink_callback_p = &nlbridge;
124	rtnl_neighs_init();
125	rtnl_ifaces_init();
126	rtnl_nexthops_init();
127	rtnl_routes_init();
128	netlink_register_proto(NETLINK_ROUTE, "NETLINK_ROUTE", rtnl_handle_message);
129}
130SYSINIT(rtnl_load, SI_SUB_PROTO_DOMAIN, SI_ORDER_THIRD, rtnl_load, NULL);
131
132static void
133rtnl_unload(void *u __unused)
134{
135	netlink_callback_p = nlbridge_orig_p;
136	netlink_unregister_proto(NETLINK_ROUTE);
137	rtnl_ifaces_destroy();
138	rtnl_neighs_destroy();
139
140	/* Wait till all consumers read nlbridge data */
141	NET_EPOCH_WAIT();
142}
143SYSUNINIT(rtnl_unload, SI_SUB_PROTO_DOMAIN, SI_ORDER_THIRD, rtnl_unload, NULL);
144