xref: /freebsd/sys/netinet/in_fib.c (revision eac7052fdebb90caf2f653e06187bdbca837b9c7)
1 /*-
2  * Copyright (c) 2015
3  * 	Alexander V. Chernikov <melifaro@FreeBSD.org>
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  * 3. Neither the name of the University nor the names of its contributors
14  *    may be used to endorse or promote products derived from this software
15  *    without specific prior written permission.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26  * OUT 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 "opt_inet.h"
34 #include "opt_route.h"
35 #include "opt_mpath.h"
36 
37 #include <sys/param.h>
38 #include <sys/systm.h>
39 #include <sys/lock.h>
40 #include <sys/rmlock.h>
41 #include <sys/malloc.h>
42 #include <sys/mbuf.h>
43 #include <sys/socket.h>
44 #include <sys/sysctl.h>
45 #include <sys/kernel.h>
46 
47 #include <net/if.h>
48 #include <net/if_var.h>
49 #include <net/if_dl.h>
50 #include <net/route.h>
51 #include <net/route/route_var.h>
52 #include <net/route/nhop.h>
53 #include <net/vnet.h>
54 
55 #ifdef RADIX_MPATH
56 #include <net/radix_mpath.h>
57 #endif
58 
59 #include <netinet/in.h>
60 #include <netinet/in_var.h>
61 #include <netinet/in_fib.h>
62 
63 #ifdef INET
64 
65 /* Verify struct route compatiblity */
66 /* Assert 'struct route_in' is compatible with 'struct route' */
67 CHK_STRUCT_ROUTE_COMPAT(struct route_in, ro_dst4);
68 
69 /*
70  * Looks up path in fib @fibnum specified by @dst.
71  * Returns path nexthop on success. Nexthop is safe to use
72  *  within the current network epoch. If longer lifetime is required,
73  *  one needs to pass NHR_REF as a flag. This will return referenced
74  *  nexthop.
75  */
76 struct nhop_object *
77 fib4_lookup(uint32_t fibnum, struct in_addr dst, uint32_t scopeid,
78     uint32_t flags, uint32_t flowid)
79 {
80 	RIB_RLOCK_TRACKER;
81 	struct rib_head *rh;
82 	struct radix_node *rn;
83 	struct rtentry *rt;
84 	struct nhop_object *nh;
85 
86 	KASSERT((fibnum < rt_numfibs), ("fib4_lookup: bad fibnum"));
87 	rh = rt_tables_get_rnh(fibnum, AF_INET);
88 	if (rh == NULL)
89 		return (NULL);
90 
91 	/* Prepare lookup key */
92 	struct sockaddr_in sin4;
93 	memset(&sin4, 0, sizeof(sin4));
94 	sin4.sin_family = AF_INET;
95 	sin4.sin_len = sizeof(struct sockaddr_in);
96 	sin4.sin_addr = dst;
97 
98 	nh = NULL;
99 	RIB_RLOCK(rh);
100 	rn = rh->rnh_matchaddr((void *)&sin4, &rh->head);
101 	if (rn != NULL && ((rn->rn_flags & RNF_ROOT) == 0)) {
102 		rt = RNTORT(rn);
103 #ifdef RADIX_MPATH
104 		if (rt_mpath_next(rt) != NULL)
105 			rt = rt_mpath_selectrte(rt, flowid);
106 #endif
107 		nh = rt->rt_nhop;
108 		/* Ensure route & ifp is UP */
109 		if (RT_LINK_IS_UP(nh->nh_ifp)) {
110 			if (flags & NHR_REF)
111 				nhop_ref_object(nh);
112 			RIB_RUNLOCK(rh);
113 			return (nh);
114 		}
115 	}
116 	RIB_RUNLOCK(rh);
117 
118 	RTSTAT_INC(rts_unreach);
119 	return (NULL);
120 }
121 
122 inline static int
123 check_urpf(const struct nhop_object *nh, uint32_t flags,
124     const struct ifnet *src_if)
125 {
126 
127 	if (src_if != NULL && nh->nh_aifp == src_if) {
128 		return (1);
129 	}
130 	if (src_if == NULL) {
131 		if ((flags & NHR_NODEFAULT) == 0)
132 			return (1);
133 		else if ((nh->nh_flags & NHF_DEFAULT) == 0)
134 			return (1);
135 	}
136 
137 	return (0);
138 }
139 
140 #ifdef RADIX_MPATH
141 inline static int
142 check_urpf_mpath(struct rtentry *rt, uint32_t flags,
143     const struct ifnet *src_if)
144 {
145 
146 	while (rt != NULL) {
147 		if (check_urpf(rt->rt_nhop, flags, src_if) != 0)
148 			return (1);
149 		rt = rt_mpath_next(rt);
150 	}
151 
152 	return (0);
153 }
154 #endif
155 
156 /*
157  * Performs reverse path forwarding lookup.
158  * If @src_if is non-zero, verifies that at least 1 path goes via
159  *   this interface.
160  * If @src_if is zero, verifies that route exist.
161  * if @flags contains NHR_NOTDEFAULT, do not consider default route.
162  *
163  * Returns 1 if route matching conditions is found, 0 otherwise.
164  */
165 int
166 fib4_check_urpf(uint32_t fibnum, struct in_addr dst, uint32_t scopeid,
167   uint32_t flags, const struct ifnet *src_if)
168 {
169 	RIB_RLOCK_TRACKER;
170 	struct rib_head *rh;
171 	struct radix_node *rn;
172 	struct rtentry *rt;
173 	int ret;
174 
175 	KASSERT((fibnum < rt_numfibs), ("fib4_check_urpf: bad fibnum"));
176 	rh = rt_tables_get_rnh(fibnum, AF_INET);
177 	if (rh == NULL)
178 		return (0);
179 
180 	/* Prepare lookup key */
181 	struct sockaddr_in sin4;
182 	memset(&sin4, 0, sizeof(sin4));
183 	sin4.sin_len = sizeof(struct sockaddr_in);
184 	sin4.sin_addr = dst;
185 
186 	RIB_RLOCK(rh);
187 	rn = rh->rnh_matchaddr((void *)&sin4, &rh->head);
188 	if (rn != NULL && ((rn->rn_flags & RNF_ROOT) == 0)) {
189 		rt = RNTORT(rn);
190 #ifdef	RADIX_MPATH
191 		ret = check_urpf_mpath(rt, flags, src_if);
192 #else
193 		ret = check_urpf(rt->rt_nhop, flags, src_if);
194 #endif
195 		RIB_RUNLOCK(rh);
196 		return (ret);
197 	}
198 	RIB_RUNLOCK(rh);
199 
200 	return (0);
201 }
202 
203 struct nhop_object *
204 fib4_lookup_debugnet(uint32_t fibnum, struct in_addr dst, uint32_t scopeid,
205     uint32_t flags)
206 {
207 	struct rib_head *rh;
208 	struct radix_node *rn;
209 	struct rtentry *rt;
210 	struct nhop_object *nh;
211 
212 	KASSERT((fibnum < rt_numfibs), ("fib4_lookup_debugnet: bad fibnum"));
213 	rh = rt_tables_get_rnh(fibnum, AF_INET);
214 	if (rh == NULL)
215 		return (NULL);
216 
217 	/* Prepare lookup key */
218 	struct sockaddr_in sin4;
219 	memset(&sin4, 0, sizeof(sin4));
220 	sin4.sin_family = AF_INET;
221 	sin4.sin_len = sizeof(struct sockaddr_in);
222 	sin4.sin_addr = dst;
223 
224 	nh = NULL;
225 	/* unlocked lookup */
226 	rn = rh->rnh_matchaddr((void *)&sin4, &rh->head);
227 	if (rn != NULL && ((rn->rn_flags & RNF_ROOT) == 0)) {
228 		rt = RNTORT(rn);
229 #ifdef RADIX_MPATH
230 		if (rt_mpath_next(rt) != NULL)
231 			rt = rt_mpath_selectrte(rt, 0);
232 #endif
233 		nh = rt->rt_nhop;
234 		/* Ensure route & ifp is UP */
235 		if (RT_LINK_IS_UP(nh->nh_ifp)) {
236 			if (flags & NHR_REF)
237 				nhop_ref_object(nh);
238 			return (nh);
239 		}
240 	}
241 
242 	return (NULL);
243 }
244 
245 #endif
246