1/*-
2 * Copyright 1994, 1995 Massachusetts Institute of Technology
3 *
4 * Permission to use, copy, modify, and distribute this software and
5 * its documentation for any purpose and without fee is hereby
6 * granted, provided that both the above copyright notice and this
7 * permission notice appear in all copies, that both the above
8 * copyright notice and this permission notice appear in all
9 * supporting documentation, and that the name of M.I.T. not be used
10 * in advertising or publicity pertaining to distribution of the
11 * software without specific, written prior permission.  M.I.T. makes
12 * no representations about the suitability of this software for any
13 * purpose.  It is provided "as is" without express or implied
14 * warranty.
15 *
16 * THIS SOFTWARE IS PROVIDED BY M.I.T. ``AS IS''.  M.I.T. DISCLAIMS
17 * ALL EXPRESS OR IMPLIED WARRANTIES WITH REGARD TO THIS SOFTWARE,
18 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
19 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT
20 * SHALL M.I.T. BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
21 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
22 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
23 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
24 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
25 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
26 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 */
29
30#include <sys/cdefs.h>
31__FBSDID("$FreeBSD$");
32
33#include <sys/param.h>
34#include <sys/systm.h>
35#include <sys/kernel.h>
36#include <sys/sysctl.h>
37#include <sys/socket.h>
38#include <sys/mbuf.h>
39
40#include <net/if.h>
41#include <net/if_var.h>
42#include <net/route.h>
43#include <net/route/route_ctl.h>
44#include <net/route/route_var.h>
45#include <net/route/nhop.h>
46#include <net/vnet.h>
47
48#include <netinet/in.h>
49#include <netinet/in_var.h>
50#include <netinet/ip.h>
51#include <netinet/ip_icmp.h>
52#include <netinet/ip_var.h>
53
54static int
55rib4_preadd(u_int fibnum, const struct sockaddr *addr, const struct sockaddr *mask,
56    struct nhop_object *nh)
57{
58	const struct sockaddr_in *addr4 = (const struct sockaddr_in *)addr;
59	uint16_t nh_type;
60	int rt_flags;
61
62	/* XXX: RTF_LOCAL && RTF_MULTICAST */
63
64	rt_flags = nhop_get_rtflags(nh);
65
66	if (rt_flags & RTF_HOST) {
67		/*
68		 * Backward compatibility:
69		 * if the destination is broadcast,
70		 * mark route as broadcast.
71		 * This behavior was useful when route cloning
72		 * was in place, so there was an explicit cloned
73		 * route for every broadcasted address.
74		 * Currently (2020-04) there is no kernel machinery
75		 * to do route cloning, though someone might explicitly
76		 * add these routes to support some cases with active-active
77		 * load balancing. Given that, retain this support.
78		 */
79		if (in_broadcast(addr4->sin_addr, nh->nh_ifp)) {
80			rt_flags |= RTF_BROADCAST;
81			nhop_set_rtflags(nh, rt_flags);
82			nh->nh_flags |= NHF_BROADCAST;
83		}
84	}
85
86	/*
87	 * Check route MTU:
88	 * inherit interface MTU if not set or
89	 * check if MTU is too large.
90	 */
91	if (nh->nh_mtu == 0) {
92		nh->nh_mtu = nh->nh_ifp->if_mtu;
93	} else if (nh->nh_mtu > nh->nh_ifp->if_mtu)
94		nh->nh_mtu = nh->nh_ifp->if_mtu;
95
96	/* Ensure that default route nhop has special flag */
97	const struct sockaddr_in *mask4 = (const struct sockaddr_in *)mask;
98	if ((rt_flags & RTF_HOST) == 0 && mask4 != NULL &&
99	    mask4->sin_addr.s_addr == 0)
100		nh->nh_flags |= NHF_DEFAULT;
101
102	/* Set nhop type to basic per-AF nhop */
103	if (nhop_get_type(nh) == 0) {
104		if (nh->nh_flags & NHF_GATEWAY)
105			nh_type = NH_TYPE_IPV4_ETHER_NHOP;
106		else
107			nh_type = NH_TYPE_IPV4_ETHER_RSLV;
108
109		nhop_set_type(nh, nh_type);
110	}
111
112	return (0);
113}
114
115/*
116 * Initialize our routing tree.
117 */
118struct rib_head *
119in_inithead(uint32_t fibnum)
120{
121	struct rib_head *rh;
122
123	rh = rt_table_init(32, AF_INET, fibnum);
124	if (rh == NULL)
125		return (NULL);
126
127	rh->rnh_preadd = rib4_preadd;
128
129	return (rh);
130}
131
132#ifdef VIMAGE
133void
134in_detachhead(struct rib_head *rh)
135{
136
137	rt_table_destroy(rh);
138}
139#endif
140
141/*
142 * This zaps old routes when the interface goes down or interface
143 * address is deleted.  In the latter case, it deletes static routes
144 * that point to this address.  If we don't do this, we may end up
145 * using the old address in the future.  The ones we always want to
146 * get rid of are things like ARP entries, since the user might down
147 * the interface, walk over to a completely different network, and
148 * plug back in.
149 */
150struct in_ifadown_arg {
151	struct ifaddr *ifa;
152	int del;
153};
154
155static int
156in_ifadownkill(const struct rtentry *rt, const struct nhop_object *nh,
157    void *xap)
158{
159	struct in_ifadown_arg *ap = xap;
160
161	if (nh->nh_ifa != ap->ifa)
162		return (0);
163
164	if ((nhop_get_rtflags(nh) & RTF_STATIC) != 0 && ap->del == 0)
165		return (0);
166
167	return (1);
168}
169
170void
171in_ifadown(struct ifaddr *ifa, int delete)
172{
173	struct in_ifadown_arg arg;
174
175	KASSERT(ifa->ifa_addr->sa_family == AF_INET,
176	    ("%s: wrong family", __func__));
177
178	arg.ifa = ifa;
179	arg.del = delete;
180
181	rib_foreach_table_walk_del(AF_INET, in_ifadownkill, &arg);
182	ifa->ifa_flags &= ~IFA_ROUTE;		/* XXXlocking? */
183}
184