xref: /freebsd/sys/netinet/in_fib.c (revision c6a33c8e88c5684876e670c8189d03ad25108d8a)
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  * 4. 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/rwlock.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/vnet.h>
52 
53 #ifdef RADIX_MPATH
54 #include <net/radix_mpath.h>
55 #endif
56 
57 #include <netinet/in.h>
58 #include <netinet/in_var.h>
59 #include <netinet/in_fib.h>
60 
61 #ifdef INET
62 static void fib4_rte_to_nh_basic(struct rtentry *rte, struct in_addr dst,
63     uint32_t flags, struct nhop4_basic *pnh4);
64 static void fib4_rte_to_nh_extended(struct rtentry *rte, struct in_addr dst,
65     uint32_t flags, struct nhop4_extended *pnh4);
66 
67 #define RNTORT(p)	((struct rtentry *)(p))
68 
69 static void
70 fib4_rte_to_nh_basic(struct rtentry *rte, struct in_addr dst,
71     uint32_t flags, struct nhop4_basic *pnh4)
72 {
73 	struct sockaddr_in *gw;
74 
75 	if ((flags & NHR_IFAIF) != 0)
76 		pnh4->nh_ifp = rte->rt_ifa->ifa_ifp;
77 	else
78 		pnh4->nh_ifp = rte->rt_ifp;
79 	pnh4->nh_mtu = min(rte->rt_mtu, rte->rt_ifp->if_mtu);
80 	if (rte->rt_flags & RTF_GATEWAY) {
81 		gw = (struct sockaddr_in *)rte->rt_gateway;
82 		pnh4->nh_addr = gw->sin_addr;
83 	} else
84 		pnh4->nh_addr = dst;
85 	/* Set flags */
86 	pnh4->nh_flags = fib_rte_to_nh_flags(rte->rt_flags);
87 	gw = (struct sockaddr_in *)rt_key(rte);
88 	if (gw->sin_addr.s_addr == 0)
89 		pnh4->nh_flags |= NHF_DEFAULT;
90 	/* TODO: Handle RTF_BROADCAST here */
91 }
92 
93 static void
94 fib4_rte_to_nh_extended(struct rtentry *rte, struct in_addr dst,
95     uint32_t flags, struct nhop4_extended *pnh4)
96 {
97 	struct sockaddr_in *gw;
98 	struct in_ifaddr *ia;
99 
100 	pnh4->nh_ifp = rte->rt_ifa->ifa_ifp;
101 	pnh4->nh_mtu = min(rte->rt_mtu, rte->rt_ifp->if_mtu);
102 	if (rte->rt_flags & RTF_GATEWAY) {
103 		gw = (struct sockaddr_in *)rte->rt_gateway;
104 		pnh4->nh_addr = gw->sin_addr;
105 	} else
106 		pnh4->nh_addr = dst;
107 	/* Set flags */
108 	pnh4->nh_flags = fib_rte_to_nh_flags(rte->rt_flags);
109 	gw = (struct sockaddr_in *)rt_key(rte);
110 	if (gw->sin_addr.s_addr == 0)
111 		pnh4->nh_flags |= NHF_DEFAULT;
112 	/* XXX: Set RTF_BROADCAST if GW address is broadcast */
113 
114 	ia = ifatoia(rte->rt_ifa);
115 	pnh4->nh_src = IA_SIN(ia)->sin_addr;
116 }
117 
118 /*
119  * Performs IPv4 route table lookup on @dst. Returns 0 on success.
120  * Stores nexthop info provided @pnh4 structure.
121  * Note that
122  * - nh_ifp cannot be safely dereferenced
123  * - nh_ifp represents logical transmit interface (rt_ifp) (e.g. if
124  *   looking up address on interface "ix0" pointer to "lo0" interface
125  *   will be returned instead of "ix0")
126  * - nh_ifp represents "address" interface if NHR_IFAIF flag is passed
127  * - howewer mtu from "transmit" interface will be returned.
128  */
129 int
130 fib4_lookup_nh_basic(uint32_t fibnum, struct in_addr dst, uint32_t flags,
131     uint32_t flowid, struct nhop4_basic *pnh4)
132 {
133 	struct radix_node_head *rh;
134 	struct radix_node *rn;
135 	struct sockaddr_in sin;
136 	struct rtentry *rte;
137 
138 	KASSERT((fibnum < rt_numfibs), ("fib4_lookup_nh_basic: bad fibnum"));
139 	rh = rt_tables_get_rnh(fibnum, AF_INET);
140 	if (rh == NULL)
141 		return (ENOENT);
142 
143 	/* Prepare lookup key */
144 	memset(&sin, 0, sizeof(sin));
145 	sin.sin_len = sizeof(struct sockaddr_in);
146 	sin.sin_addr = dst;
147 
148 	RADIX_NODE_HEAD_RLOCK(rh);
149 	rn = rh->rnh_matchaddr((void *)&sin, rh);
150 	if (rn != NULL && ((rn->rn_flags & RNF_ROOT) == 0)) {
151 		rte = RNTORT(rn);
152 		/* Ensure route & ifp is UP */
153 		if (RT_LINK_IS_UP(rte->rt_ifp)) {
154 			fib4_rte_to_nh_basic(rte, dst, flags, pnh4);
155 			RADIX_NODE_HEAD_RUNLOCK(rh);
156 
157 			return (0);
158 		}
159 	}
160 	RADIX_NODE_HEAD_RUNLOCK(rh);
161 
162 	return (ENOENT);
163 }
164 
165 /*
166  * Performs IPv4 route table lookup on @dst. Returns 0 on success.
167  * Stores extende nexthop info provided @pnh4 structure.
168  * Note that
169  * - nh_ifp cannot be safely dereferenced unless NHR_REF is specified.
170  * - in that case you need to call fib4_free_nh_ext()
171  * - nh_ifp represents logical transmit interface (rt_ifp) (e.g. if
172  *   looking up address of interface "ix0" pointer to "lo0" interface
173  *   will be returned instead of "ix0")
174  * - nh_ifp represents "address" interface if NHR_IFAIF flag is passed
175  * - howewer mtu from "transmit" interface will be returned.
176  */
177 int
178 fib4_lookup_nh_ext(uint32_t fibnum, struct in_addr dst, uint32_t flowid,
179     uint32_t flags, struct nhop4_extended *pnh4)
180 {
181 	struct radix_node_head *rh;
182 	struct radix_node *rn;
183 	struct sockaddr_in sin;
184 	struct rtentry *rte;
185 
186 	KASSERT((fibnum < rt_numfibs), ("fib4_lookup_nh_ext: bad fibnum"));
187 	rh = rt_tables_get_rnh(fibnum, AF_INET);
188 	if (rh == NULL)
189 		return (ENOENT);
190 
191 	/* Prepare lookup key */
192 	memset(&sin, 0, sizeof(sin));
193 	sin.sin_len = sizeof(struct sockaddr_in);
194 	sin.sin_addr = dst;
195 
196 	RADIX_NODE_HEAD_RLOCK(rh);
197 	rn = rh->rnh_matchaddr((void *)&sin, rh);
198 	if (rn != NULL && ((rn->rn_flags & RNF_ROOT) == 0)) {
199 		rte = RNTORT(rn);
200 		/* Ensure route & ifp is UP */
201 		if (RT_LINK_IS_UP(rte->rt_ifp)) {
202 			fib4_rte_to_nh_extended(rte, dst, flags, pnh4);
203 			if ((flags & NHR_REF) != 0) {
204 				/* TODO: lwref on egress ifp's ? */
205 			}
206 			RADIX_NODE_HEAD_RUNLOCK(rh);
207 
208 			return (0);
209 		}
210 	}
211 	RADIX_NODE_HEAD_RUNLOCK(rh);
212 
213 	return (ENOENT);
214 }
215 
216 void
217 fib4_free_nh_ext(uint32_t fibnum, struct nhop4_extended *pnh4)
218 {
219 
220 }
221 
222 #endif
223