FreeBSD/Linux Kernel Cross Reference
sys/net/radix_mpath.c
1 /* $KAME: radix_mpath.c,v 1.17 2004/11/08 10:29:39 itojun Exp $ */
2
3 /*
4 * Copyright (C) 2001 WIDE Project.
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 * 3. Neither the name of the project nor the names of its contributors
16 * may be used to endorse or promote products derived from this software
17 * without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 * THE AUTHORS DO NOT GUARANTEE THAT THIS SOFTWARE DOES NOT INFRINGE
31 * ANY OTHERS' INTELLECTUAL PROPERTIES. IN NO EVENT SHALL THE AUTHORS
32 * BE LIABLE FOR ANY INFRINGEMENT OF ANY OTHERS' INTELLECTUAL
33 * PROPERTIES.
34 */
35
36 #include <sys/cdefs.h>
37 __FBSDID("$FreeBSD: releng/9.0/sys/net/radix_mpath.c 225163 2011-08-25 04:31:20Z qingli $");
38
39 #include "opt_inet.h"
40 #include "opt_inet6.h"
41
42 #include <sys/param.h>
43 #include <sys/systm.h>
44 #include <sys/malloc.h>
45 #include <sys/socket.h>
46 #include <sys/domain.h>
47 #include <sys/syslog.h>
48 #include <net/radix.h>
49 #include <net/radix_mpath.h>
50 #include <net/route.h>
51 #include <net/if.h>
52 #include <net/if_var.h>
53
54 /*
55 * give some jitter to hash, to avoid synchronization between routers
56 */
57 static uint32_t hashjitter;
58
59 int
60 rn_mpath_capable(struct radix_node_head *rnh)
61 {
62
63 return rnh->rnh_multipath;
64 }
65
66 struct radix_node *
67 rn_mpath_next(struct radix_node *rn)
68 {
69 struct radix_node *next;
70
71 if (!rn->rn_dupedkey)
72 return NULL;
73 next = rn->rn_dupedkey;
74 if (rn->rn_mask == next->rn_mask)
75 return next;
76 else
77 return NULL;
78 }
79
80 uint32_t
81 rn_mpath_count(struct radix_node *rn)
82 {
83 uint32_t i = 0;
84 struct rtentry *rt;
85
86 while (rn != NULL) {
87 rt = (struct rtentry *)rn;
88 i += rt->rt_rmx.rmx_weight;
89 rn = rn_mpath_next(rn);
90 }
91 return (i);
92 }
93
94 struct rtentry *
95 rt_mpath_matchgate(struct rtentry *rt, struct sockaddr *gate)
96 {
97 struct radix_node *rn;
98
99 if (!gate || !rt->rt_gateway)
100 return NULL;
101
102 /* beyond here, we use rn as the master copy */
103 rn = (struct radix_node *)rt;
104 do {
105 rt = (struct rtentry *)rn;
106 /*
107 * we are removing an address alias that has
108 * the same prefix as another address
109 * we need to compare the interface address because
110 * rt_gateway is a special sockadd_dl structure
111 */
112 if (rt->rt_gateway->sa_family == AF_LINK) {
113 if (!memcmp(rt->rt_ifa->ifa_addr, gate, gate->sa_len))
114 break;
115 } else {
116 if (rt->rt_gateway->sa_len == gate->sa_len &&
117 !memcmp(rt->rt_gateway, gate, gate->sa_len))
118 break;
119 }
120 } while ((rn = rn_mpath_next(rn)) != NULL);
121
122 return (struct rtentry *)rn;
123 }
124
125 /*
126 * go through the chain and unlink "rt" from the list
127 * the caller will free "rt"
128 */
129 int
130 rt_mpath_deldup(struct rtentry *headrt, struct rtentry *rt)
131 {
132 struct radix_node *t, *tt;
133
134 if (!headrt || !rt)
135 return (0);
136 t = (struct radix_node *)headrt;
137 tt = rn_mpath_next(t);
138 while (tt) {
139 if (tt == (struct radix_node *)rt) {
140 t->rn_dupedkey = tt->rn_dupedkey;
141 tt->rn_dupedkey = NULL;
142 tt->rn_flags &= ~RNF_ACTIVE;
143 tt[1].rn_flags &= ~RNF_ACTIVE;
144 return (1);
145 }
146 t = tt;
147 tt = rn_mpath_next((struct radix_node *)t);
148 }
149 return (0);
150 }
151
152 /*
153 * check if we have the same key/mask/gateway on the table already.
154 */
155 int
156 rt_mpath_conflict(struct radix_node_head *rnh, struct rtentry *rt,
157 struct sockaddr *netmask)
158 {
159 struct radix_node *rn, *rn1;
160 struct rtentry *rt1;
161 char *p, *q, *eq;
162 int same, l, skip;
163
164 rn = (struct radix_node *)rt;
165 rn1 = rnh->rnh_lookup(rt_key(rt), netmask, rnh);
166 if (!rn1 || rn1->rn_flags & RNF_ROOT)
167 return 0;
168
169 /*
170 * unlike other functions we have in this file, we have to check
171 * all key/mask/gateway as rnh_lookup can match less specific entry.
172 */
173 rt1 = (struct rtentry *)rn1;
174
175 /* compare key. */
176 if (rt_key(rt1)->sa_len != rt_key(rt)->sa_len ||
177 bcmp(rt_key(rt1), rt_key(rt), rt_key(rt1)->sa_len))
178 goto different;
179
180 /* key was the same. compare netmask. hairy... */
181 if (rt_mask(rt1) && netmask) {
182 skip = rnh->rnh_treetop->rn_offset;
183 if (rt_mask(rt1)->sa_len > netmask->sa_len) {
184 /*
185 * as rt_mask(rt1) is made optimal by radix.c,
186 * there must be some 1-bits on rt_mask(rt1)
187 * after netmask->sa_len. therefore, in
188 * this case, the entries are different.
189 */
190 if (rt_mask(rt1)->sa_len > skip)
191 goto different;
192 else {
193 /* no bits to compare, i.e. same*/
194 goto maskmatched;
195 }
196 }
197
198 l = rt_mask(rt1)->sa_len;
199 if (skip > l) {
200 /* no bits to compare, i.e. same */
201 goto maskmatched;
202 }
203 p = (char *)rt_mask(rt1);
204 q = (char *)netmask;
205 if (bcmp(p + skip, q + skip, l - skip))
206 goto different;
207 /*
208 * need to go through all the bit, as netmask is not
209 * optimal and can contain trailing 0s
210 */
211 eq = (char *)netmask + netmask->sa_len;
212 q += l;
213 same = 1;
214 while (eq > q)
215 if (*q++) {
216 same = 0;
217 break;
218 }
219 if (!same)
220 goto different;
221 } else if (!rt_mask(rt1) && !netmask)
222 ; /* no mask to compare, i.e. same */
223 else {
224 /* one has mask and the other does not, different */
225 goto different;
226 }
227
228 maskmatched:
229
230 /* key/mask were the same. compare gateway for all multipaths */
231 do {
232 rt1 = (struct rtentry *)rn1;
233
234 /* sanity: no use in comparing the same thing */
235 if (rn1 == rn)
236 continue;
237
238 if (rt1->rt_gateway->sa_family == AF_LINK) {
239 if (rt1->rt_ifa->ifa_addr->sa_len != rt->rt_ifa->ifa_addr->sa_len ||
240 bcmp(rt1->rt_ifa->ifa_addr, rt->rt_ifa->ifa_addr,
241 rt1->rt_ifa->ifa_addr->sa_len))
242 continue;
243 } else {
244 if (rt1->rt_gateway->sa_len != rt->rt_gateway->sa_len ||
245 bcmp(rt1->rt_gateway, rt->rt_gateway,
246 rt1->rt_gateway->sa_len))
247 continue;
248 }
249
250 /* all key/mask/gateway are the same. conflicting entry. */
251 return EEXIST;
252 } while ((rn1 = rn_mpath_next(rn1)) != NULL);
253
254 different:
255 return 0;
256 }
257
258 void
259 rtalloc_mpath_fib(struct route *ro, uint32_t hash, u_int fibnum)
260 {
261 struct radix_node *rn0, *rn;
262 u_int32_t n;
263 struct rtentry *rt;
264 int64_t weight;
265
266 /*
267 * XXX we don't attempt to lookup cached route again; what should
268 * be done for sendto(3) case?
269 */
270 if (ro->ro_rt && ro->ro_rt->rt_ifp && (ro->ro_rt->rt_flags & RTF_UP)
271 && RT_LINK_IS_UP(ro->ro_rt->rt_ifp))
272 return;
273 ro->ro_rt = rtalloc1_fib(&ro->ro_dst, 1, 0, fibnum);
274
275 /* if the route does not exist or it is not multipath, don't care */
276 if (ro->ro_rt == NULL)
277 return;
278 if (rn_mpath_next((struct radix_node *)ro->ro_rt) == NULL) {
279 RT_UNLOCK(ro->ro_rt);
280 return;
281 }
282
283 /* beyond here, we use rn as the master copy */
284 rn0 = rn = (struct radix_node *)ro->ro_rt;
285 n = rn_mpath_count(rn0);
286
287 /* gw selection by Modulo-N Hash (RFC2991) XXX need improvement? */
288 hash += hashjitter;
289 hash %= n;
290 for (weight = abs((int32_t)hash), rt = ro->ro_rt;
291 weight >= rt->rt_rmx.rmx_weight && rn;
292 weight -= rt->rt_rmx.rmx_weight) {
293
294 /* stay within the multipath routes */
295 if (rn->rn_dupedkey && rn->rn_mask != rn->rn_dupedkey->rn_mask)
296 break;
297 rn = rn->rn_dupedkey;
298 rt = (struct rtentry *)rn;
299 }
300 /* XXX try filling rt_gwroute and avoid unreachable gw */
301
302 /* gw selection has failed - there must be only zero weight routes */
303 if (!rn) {
304 RT_UNLOCK(ro->ro_rt);
305 ro->ro_rt = NULL;
306 return;
307 }
308 if (ro->ro_rt != rt) {
309 RTFREE_LOCKED(ro->ro_rt);
310 ro->ro_rt = (struct rtentry *)rn;
311 RT_LOCK(ro->ro_rt);
312 RT_ADDREF(ro->ro_rt);
313
314 }
315 RT_UNLOCK(ro->ro_rt);
316 }
317
318 extern int in6_inithead(void **head, int off);
319 extern int in_inithead(void **head, int off);
320
321 #ifdef INET
322 int
323 rn4_mpath_inithead(void **head, int off)
324 {
325 struct radix_node_head *rnh;
326
327 hashjitter = arc4random();
328 if (in_inithead(head, off) == 1) {
329 rnh = (struct radix_node_head *)*head;
330 rnh->rnh_multipath = 1;
331 return 1;
332 } else
333 return 0;
334 }
335 #endif
336
337 #ifdef INET6
338 int
339 rn6_mpath_inithead(void **head, int off)
340 {
341 struct radix_node_head *rnh;
342
343 hashjitter = arc4random();
344 if (in6_inithead(head, off) == 1) {
345 rnh = (struct radix_node_head *)*head;
346 rnh->rnh_multipath = 1;
347 return 1;
348 } else
349 return 0;
350 }
351
352 #endif
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