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/8.1/sys/net/radix_mpath.c 206067 2010-04-02 05:02:50Z 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 (!rn_mpath_next((struct radix_node *)rt))
100 return rt;
101
102 if (!gate)
103 return NULL;
104
105 /* beyond here, we use rn as the master copy */
106 rn = (struct radix_node *)rt;
107 do {
108 rt = (struct rtentry *)rn;
109 /*
110 * we are removing an address alias that has
111 * the same prefix as another address
112 * we need to compare the interface address because
113 * rt_gateway is a special sockadd_dl structure
114 */
115 if (rt->rt_gateway->sa_family == AF_LINK) {
116 if (!memcmp(rt->rt_ifa->ifa_addr, gate, gate->sa_len))
117 break;
118 } else {
119 if (rt->rt_gateway->sa_len == gate->sa_len &&
120 !memcmp(rt->rt_gateway, gate, gate->sa_len))
121 break;
122 }
123 } while ((rn = rn_mpath_next(rn)) != NULL);
124
125 return (struct rtentry *)rn;
126 }
127
128 /*
129 * go through the chain and unlink "rt" from the list
130 * the caller will free "rt"
131 */
132 int
133 rt_mpath_deldup(struct rtentry *headrt, struct rtentry *rt)
134 {
135 struct radix_node *t, *tt;
136
137 if (!headrt || !rt)
138 return (0);
139 t = (struct radix_node *)headrt;
140 tt = rn_mpath_next(t);
141 while (tt) {
142 if (tt == (struct radix_node *)rt) {
143 t->rn_dupedkey = tt->rn_dupedkey;
144 tt->rn_dupedkey = NULL;
145 tt->rn_flags &= ~RNF_ACTIVE;
146 tt[1].rn_flags &= ~RNF_ACTIVE;
147 return (1);
148 }
149 t = tt;
150 tt = rn_mpath_next((struct radix_node *)t);
151 }
152 return (0);
153 }
154
155 /*
156 * check if we have the same key/mask/gateway on the table already.
157 */
158 int
159 rt_mpath_conflict(struct radix_node_head *rnh, struct rtentry *rt,
160 struct sockaddr *netmask)
161 {
162 struct radix_node *rn, *rn1;
163 struct rtentry *rt1;
164 char *p, *q, *eq;
165 int same, l, skip;
166
167 rn = (struct radix_node *)rt;
168 rn1 = rnh->rnh_lookup(rt_key(rt), netmask, rnh);
169 if (!rn1 || rn1->rn_flags & RNF_ROOT)
170 return 0;
171
172 /*
173 * unlike other functions we have in this file, we have to check
174 * all key/mask/gateway as rnh_lookup can match less specific entry.
175 */
176 rt1 = (struct rtentry *)rn1;
177
178 /* compare key. */
179 if (rt_key(rt1)->sa_len != rt_key(rt)->sa_len ||
180 bcmp(rt_key(rt1), rt_key(rt), rt_key(rt1)->sa_len))
181 goto different;
182
183 /* key was the same. compare netmask. hairy... */
184 if (rt_mask(rt1) && netmask) {
185 skip = rnh->rnh_treetop->rn_offset;
186 if (rt_mask(rt1)->sa_len > netmask->sa_len) {
187 /*
188 * as rt_mask(rt1) is made optimal by radix.c,
189 * there must be some 1-bits on rt_mask(rt1)
190 * after netmask->sa_len. therefore, in
191 * this case, the entries are different.
192 */
193 if (rt_mask(rt1)->sa_len > skip)
194 goto different;
195 else {
196 /* no bits to compare, i.e. same*/
197 goto maskmatched;
198 }
199 }
200
201 l = rt_mask(rt1)->sa_len;
202 if (skip > l) {
203 /* no bits to compare, i.e. same */
204 goto maskmatched;
205 }
206 p = (char *)rt_mask(rt1);
207 q = (char *)netmask;
208 if (bcmp(p + skip, q + skip, l - skip))
209 goto different;
210 /*
211 * need to go through all the bit, as netmask is not
212 * optimal and can contain trailing 0s
213 */
214 eq = (char *)netmask + netmask->sa_len;
215 q += l;
216 same = 1;
217 while (eq > q)
218 if (*q++) {
219 same = 0;
220 break;
221 }
222 if (!same)
223 goto different;
224 } else if (!rt_mask(rt1) && !netmask)
225 ; /* no mask to compare, i.e. same */
226 else {
227 /* one has mask and the other does not, different */
228 goto different;
229 }
230
231 maskmatched:
232
233 /* key/mask were the same. compare gateway for all multipaths */
234 do {
235 rt1 = (struct rtentry *)rn1;
236
237 /* sanity: no use in comparing the same thing */
238 if (rn1 == rn)
239 continue;
240
241 if (rt1->rt_gateway->sa_family == AF_LINK) {
242 if (rt1->rt_ifa->ifa_addr->sa_len != rt->rt_ifa->ifa_addr->sa_len ||
243 bcmp(rt1->rt_ifa->ifa_addr, rt->rt_ifa->ifa_addr,
244 rt1->rt_ifa->ifa_addr->sa_len))
245 continue;
246 } else {
247 if (rt1->rt_gateway->sa_len != rt->rt_gateway->sa_len ||
248 bcmp(rt1->rt_gateway, rt->rt_gateway,
249 rt1->rt_gateway->sa_len))
250 continue;
251 }
252
253 /* all key/mask/gateway are the same. conflicting entry. */
254 return EEXIST;
255 } while ((rn1 = rn_mpath_next(rn1)) != NULL);
256
257 different:
258 return 0;
259 }
260
261 void
262 rtalloc_mpath_fib(struct route *ro, uint32_t hash, u_int fibnum)
263 {
264 struct radix_node *rn0, *rn;
265 u_int32_t n;
266 struct rtentry *rt;
267 int64_t weight;
268
269 /*
270 * XXX we don't attempt to lookup cached route again; what should
271 * be done for sendto(3) case?
272 */
273 if (ro->ro_rt && ro->ro_rt->rt_ifp && (ro->ro_rt->rt_flags & RTF_UP)
274 && RT_LINK_IS_UP(ro->ro_rt->rt_ifp))
275 return;
276 ro->ro_rt = rtalloc1_fib(&ro->ro_dst, 1, 0, fibnum);
277
278 /* if the route does not exist or it is not multipath, don't care */
279 if (ro->ro_rt == NULL)
280 return;
281 if (rn_mpath_next((struct radix_node *)ro->ro_rt) == NULL) {
282 RT_UNLOCK(ro->ro_rt);
283 return;
284 }
285
286 /* beyond here, we use rn as the master copy */
287 rn0 = rn = (struct radix_node *)ro->ro_rt;
288 n = rn_mpath_count(rn0);
289
290 /* gw selection by Modulo-N Hash (RFC2991) XXX need improvement? */
291 hash += hashjitter;
292 hash %= n;
293 for (weight = abs((int32_t)hash), rt = ro->ro_rt;
294 weight >= rt->rt_rmx.rmx_weight && rn;
295 weight -= rt->rt_rmx.rmx_weight) {
296
297 /* stay within the multipath routes */
298 if (rn->rn_dupedkey && rn->rn_mask != rn->rn_dupedkey->rn_mask)
299 break;
300 rn = rn->rn_dupedkey;
301 rt = (struct rtentry *)rn;
302 }
303 /* XXX try filling rt_gwroute and avoid unreachable gw */
304
305 /* gw selection has failed - there must be only zero weight routes */
306 if (!rn) {
307 RT_UNLOCK(ro->ro_rt);
308 ro->ro_rt = NULL;
309 return;
310 }
311 if (ro->ro_rt != rt) {
312 RTFREE_LOCKED(ro->ro_rt);
313 ro->ro_rt = (struct rtentry *)rn;
314 RT_LOCK(ro->ro_rt);
315 RT_ADDREF(ro->ro_rt);
316
317 }
318 RT_UNLOCK(ro->ro_rt);
319 }
320
321 extern int in6_inithead(void **head, int off);
322 extern int in_inithead(void **head, int off);
323
324 #ifdef INET
325 int
326 rn4_mpath_inithead(void **head, int off)
327 {
328 struct radix_node_head *rnh;
329
330 hashjitter = arc4random();
331 if (in_inithead(head, off) == 1) {
332 rnh = (struct radix_node_head *)*head;
333 rnh->rnh_multipath = 1;
334 return 1;
335 } else
336 return 0;
337 }
338 #endif
339
340 #ifdef INET6
341 int
342 rn6_mpath_inithead(void **head, int off)
343 {
344 struct radix_node_head *rnh;
345
346 hashjitter = arc4random();
347 if (in6_inithead(head, off) == 1) {
348 rnh = (struct radix_node_head *)*head;
349 rnh->rnh_multipath = 1;
350 return 1;
351 } else
352 return 0;
353 }
354
355 #endif
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