-
Notifications
You must be signed in to change notification settings - Fork 24
/
ip6_flow.c
523 lines (459 loc) · 12.9 KB
/
ip6_flow.c
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
/* $NetBSD: ip6_flow.c,v 1.2.4.5 2007/05/07 10:56:03 yamt Exp $ */
/*-
* Copyright (c) 2007 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by the 3am Software Foundry ("3am"). It was developed by Liam J. Foy
* <liamjfoy@netbsd.org> and Matt Thomas <matt@netbsd.org>.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the NetBSD
* Foundation, Inc. and its contributors.
* 4. Neither the name of The NetBSD Foundation nor the names of its
* contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
* IPv6 version was developed by Liam J. Foy. Original source existed in IPv4
* format developed by Matt Thomas. Thanks to Joerg Sonnenberger, Matt
* Thomas and Christos Zoulas.
*
* Thanks to Liverpool John Moores University, especially Dr. David Llewellyn-Jones
* for providing resources (to test) and Professor Madjid Merabti.
*/
#include <sys/cdefs.h>
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/domain.h>
#include <sys/protosw.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/time.h>
#include <sys/kernel.h>
#include <sys/pool.h>
#include <sys/sysctl.h>
#include <net/if.h>
#include <net/if_dl.h>
#include <net/route.h>
#include <net/pfil.h>
#include <netinet/in.h>
#include <netinet6/in6_var.h>
#include <netinet/in_systm.h>
#include <netinet/ip6.h>
#include <netinet6/ip6_var.h>
/*
* IPv6 Fast Forward caches/hashes flows from one source to destination.
*
* Upon a successful forward IPv6FF caches and hashes details such as the
* route, source and destination. Once another packet is received matching
* the source and destination the packet is forwarded straight onto if_output
* using the cached details.
*
* Example:
* ether/fddi_input -> ip6flow_fastfoward -> if_output
*/
POOL_INIT(ip6flow_pool, sizeof(struct ip6flow), 0, 0, 0, "ip6flowpl", NULL,
IPL_NET);
LIST_HEAD(ip6flowhead, ip6flow);
/*
* We could use IPv4 defines (IPFLOW_HASHBITS) but we'll
* use our own (possibly for future expansion).
*/
#define IP6FLOW_TIMER (5 * PR_SLOWHZ)
#define IP6FLOW_DEFAULT_HASHSIZE (1 << IP6FLOW_HASHBITS)
static struct ip6flowhead *ip6flowtable = NULL;
static struct ip6flowhead ip6flowlist;
static int ip6flow_inuse;
/*
* Insert an ip6flow into the list.
*/
#define IP6FLOW_INSERT(bucket, ip6f) \
do { \
LIST_INSERT_HEAD((bucket), (ip6f), ip6f_hash); \
LIST_INSERT_HEAD(&ip6flowlist, (ip6f), ip6f_list); \
} while (/*CONSTCOND*/ 0)
/*
* Remove an ip6flow from the list.
*/
#define IP6FLOW_REMOVE(ip6f) \
do { \
LIST_REMOVE((ip6f), ip6f_hash); \
LIST_REMOVE((ip6f), ip6f_list); \
} while (/*CONSTCOND*/ 0)
#ifndef IP6FLOW_DEFAULT
#define IP6FLOW_DEFAULT 256
#endif
int ip6_maxflows = IP6FLOW_DEFAULT;
int ip6_hashsize = IP6FLOW_DEFAULT_HASHSIZE;
/*
* Calculate hash table position.
*/
static size_t
ip6flow_hash(struct ip6_hdr *ip6)
{
size_t hash;
uint32_t dst_sum, src_sum;
size_t idx;
src_sum = ip6->ip6_src.s6_addr32[0] + ip6->ip6_src.s6_addr32[1]
+ ip6->ip6_src.s6_addr32[2] + ip6->ip6_src.s6_addr32[3];
dst_sum = ip6->ip6_dst.s6_addr32[0] + ip6->ip6_dst.s6_addr32[1]
+ ip6->ip6_dst.s6_addr32[2] + ip6->ip6_dst.s6_addr32[3];
hash = ip6->ip6_flow;
for (idx = 0; idx < 32; idx += IP6FLOW_HASHBITS)
hash += (dst_sum >> (32 - idx)) + (src_sum >> idx);
return hash & (ip6_hashsize-1);
}
/*
* Check to see if a flow already exists - if so return it.
*/
static struct ip6flow *
ip6flow_lookup(struct ip6_hdr *ip6)
{
size_t hash;
struct ip6flow *ip6f;
hash = ip6flow_hash(ip6);
LIST_FOREACH(ip6f, &ip6flowtable[hash], ip6f_hash) {
if (IN6_ARE_ADDR_EQUAL(&ip6->ip6_dst, &ip6f->ip6f_dst)
&& IN6_ARE_ADDR_EQUAL(&ip6->ip6_src, &ip6f->ip6f_src)
&& ip6f->ip6f_flow == ip6->ip6_flow) {
/* A cached flow has been found. */
return ip6f;
}
}
return NULL;
}
/*
* Allocate memory and initialise lists. This function is called
* from ip6_init and called there after to resize the hash table.
* If a newly sized table cannot be malloc'ed we just continue
* to use the old one.
*/
int
ip6flow_init(int table_size)
{
struct ip6flowhead *new_table;
size_t i;
new_table = (struct ip6flowhead *)malloc(sizeof(struct ip6flowhead) *
table_size, M_RTABLE, M_NOWAIT);
if (new_table == NULL)
return 1;
if (ip6flowtable != NULL)
free(ip6flowtable, M_RTABLE);
ip6flowtable = new_table;
ip6_hashsize = table_size;
LIST_INIT(&ip6flowlist);
for (i = 0; i < ip6_hashsize; i++)
LIST_INIT(&ip6flowtable[i]);
return 0;
}
/*
* IPv6 Fast Forward routine. Attempt to forward the packet -
* if any problems are found return to the main IPv6 input
* routine to deal with.
*/
int
ip6flow_fastforward(struct mbuf *m)
{
struct ip6flow *ip6f;
struct ip6_hdr *ip6;
struct rtentry *rt;
const struct sockaddr *dst;
int error;
/*
* Are we forwarding packets and have flows?
*/
if (!ip6_forwarding || ip6flow_inuse == 0)
return 0;
/*
* At least size of IPv6 Header?
*/
if (m->m_len < sizeof(struct ip6_hdr))
return 0;
/*
* Was packet received as a link-level multicast or broadcast?
* If so, don't try to fast forward.
*/
if ((m->m_flags & (M_BCAST|M_MCAST)) != 0)
return 0;
if (IP6_HDR_ALIGNED_P(mtod(m, void *)) == 0) {
if ((m = m_copyup(m, sizeof(struct ip6_hdr),
(max_linkhdr + 3) & ~3)) == NULL) {
return 0;
}
} else if (__predict_false(m->m_len < sizeof(struct ip6_hdr))) {
if ((m = m_pullup(m, sizeof(struct ip6_hdr))) == NULL) {
return 0;
}
}
ip6 = mtod(m, struct ip6_hdr *);
if ((ip6->ip6_vfc & IPV6_VERSION_MASK) != IPV6_VERSION) {
/* Bad version. */
return 0;
}
/*
* If we have a hop-by-hop extension we must process it.
* We just leave this up to ip6_input to deal with.
*/
if (ip6->ip6_nxt == IPPROTO_HOPOPTS)
return 0;
/*
* Attempt to find a flow.
*/
if ((ip6f = ip6flow_lookup(ip6)) == NULL) {
/* No flow found. */
return 0;
}
/*
* Route and interface still up?
*/
rtcache_check(&ip6f->ip6f_ro);
rt = ip6f->ip6f_ro.ro_rt;
if (rt == NULL || (rt->rt_ifp->if_flags & IFF_UP) == 0) {
/* Route or interface is down */
return 0;
}
/*
* Packet size greater than MTU?
*/
if (m->m_pkthdr.len > rt->rt_ifp->if_mtu) {
/* Return to main IPv6 input function. */
return 0;
}
if (ip6->ip6_hlim <= IPV6_HLIMDEC)
return 0;
/* Decrement hop limit (same as TTL) */
ip6->ip6_hlim -= IPV6_HLIMDEC;
if (rt->rt_flags & RTF_GATEWAY)
dst = rt->rt_gateway;
else
dst = rtcache_getdst(&ip6f->ip6f_ro);
PRT_SLOW_ARM(ip6f->ip6f_timer, IP6FLOW_TIMER);
ip6f->ip6f_uses++;
/* Send on its way - straight to the interface output routine. */
if ((error = (*rt->rt_ifp->if_output)(rt->rt_ifp, m, dst, rt)) != 0) {
ip6f->ip6f_dropped++;
} else {
ip6f->ip6f_forwarded++;
}
return 1;
}
/*
* Add the IPv6 flow statistics to the main IPv6 statistics.
*/
static void
ip6flow_addstats(struct ip6flow *ip6f)
{
rtcache_check(&ip6f->ip6f_ro);
if (ip6f->ip6f_ro.ro_rt != NULL)
ip6f->ip6f_ro.ro_rt->rt_use += ip6f->ip6f_uses;
ip6stat.ip6s_fastforwardflows = ip6flow_inuse;
ip6stat.ip6s_cantforward += ip6f->ip6f_dropped;
ip6stat.ip6s_odropped += ip6f->ip6f_dropped;
ip6stat.ip6s_total += ip6f->ip6f_uses;
ip6stat.ip6s_forward += ip6f->ip6f_forwarded;
ip6stat.ip6s_fastforward += ip6f->ip6f_forwarded;
}
/*
* Add statistics and free the flow.
*/
static void
ip6flow_free(struct ip6flow *ip6f)
{
int s;
/*
* Remove the flow from the hash table (at elevated IPL).
* Once it's off the list, we can deal with it at normal
* network IPL.
*/
s = splnet();
IP6FLOW_REMOVE(ip6f);
splx(s);
ip6flow_inuse--;
ip6flow_addstats(ip6f);
rtcache_free(&ip6f->ip6f_ro);
pool_put(&ip6flow_pool, ip6f);
}
/*
* Reap one or more flows - ip6flow_reap may remove
* multiple flows if net.inet6.ip6.maxflows is reduced.
*/
struct ip6flow *
ip6flow_reap(int just_one)
{
while (just_one || ip6flow_inuse > ip6_maxflows) {
struct ip6flow *ip6f, *maybe_ip6f = NULL;
int s;
ip6f = LIST_FIRST(&ip6flowlist);
while (ip6f != NULL) {
/*
* If this no longer points to a valid route -
* reclaim it.
*/
rtcache_check(&ip6f->ip6f_ro);
if (ip6f->ip6f_ro.ro_rt == NULL)
goto done;
/*
* choose the one that's been least recently
* used or has had the least uses in the
* last 1.5 intervals.
*/
if (maybe_ip6f == NULL ||
ip6f->ip6f_timer < maybe_ip6f->ip6f_timer ||
(ip6f->ip6f_timer == maybe_ip6f->ip6f_timer &&
ip6f->ip6f_last_uses + ip6f->ip6f_uses <
maybe_ip6f->ip6f_last_uses +
maybe_ip6f->ip6f_uses))
maybe_ip6f = ip6f;
ip6f = LIST_NEXT(ip6f, ip6f_list);
}
ip6f = maybe_ip6f;
done:
/*
* Remove the entry from the flow table
*/
s = splnet();
IP6FLOW_REMOVE(ip6f);
splx(s);
rtcache_free(&ip6f->ip6f_ro);
if (just_one) {
ip6flow_addstats(ip6f);
return ip6f;
}
ip6flow_inuse--;
ip6flow_addstats(ip6f);
pool_put(&ip6flow_pool, ip6f);
}
return NULL;
}
void
ip6flow_slowtimo(void)
{
struct ip6flow *ip6f, *next_ip6f;
for (ip6f = LIST_FIRST(&ip6flowlist); ip6f != NULL; ip6f = next_ip6f) {
next_ip6f = LIST_NEXT(ip6f, ip6f_list);
rtcache_check(&ip6f->ip6f_ro);
if (PRT_SLOW_ISEXPIRED(ip6f->ip6f_timer) ||
ip6f->ip6f_ro.ro_rt == NULL) {
ip6flow_free(ip6f);
} else {
ip6f->ip6f_last_uses = ip6f->ip6f_uses;
ip6flow_addstats(ip6f);
ip6f->ip6f_uses = 0;
ip6f->ip6f_dropped = 0;
ip6f->ip6f_forwarded = 0;
}
}
}
/*
* We have successfully forwarded a packet using the normal
* IPv6 stack. Now create/update a flow.
*/
void
ip6flow_create(const struct route *ro, struct mbuf *m)
{
struct ip6_hdr *ip6;
struct ip6flow *ip6f;
size_t hash;
int s;
ip6 = mtod(m, struct ip6_hdr *);
/*
* If IPv6 Fast Forward is disabled, don't create a flow.
* It can be disabled by setting net.inet6.ip6.maxflows to 0.
*
* Don't create a flow for ICMPv6 messages.
*/
if (ip6_maxflows == 0 || ip6->ip6_nxt == IPPROTO_IPV6_ICMP)
return;
/*
* See if an existing flow exists. If so:
* - Remove the flow
* - Add flow statistics
* - Free the route
* - Reset statistics
*
* If a flow doesn't exist allocate a new one if
* ip6_maxflows hasn't reached its limit. If it has
* been reached, reap some flows.
*/
ip6f = ip6flow_lookup(ip6);
if (ip6f == NULL) {
if (ip6flow_inuse >= ip6_maxflows) {
ip6f = ip6flow_reap(1);
} else {
ip6f = pool_get(&ip6flow_pool, PR_NOWAIT);
if (ip6f == NULL)
return;
ip6flow_inuse++;
}
memset(ip6f, 0, sizeof(*ip6f));
} else {
s = splnet();
IP6FLOW_REMOVE(ip6f);
splx(s);
ip6flow_addstats(ip6f);
rtcache_free(&ip6f->ip6f_ro);
ip6f->ip6f_uses = 0;
ip6f->ip6f_last_uses = 0;
ip6f->ip6f_dropped = 0;
ip6f->ip6f_forwarded = 0;
}
/*
* Fill in the updated/new details.
*/
rtcache_copy(&ip6f->ip6f_ro, ro);
ip6f->ip6f_dst = ip6->ip6_dst;
ip6f->ip6f_src = ip6->ip6_src;
ip6f->ip6f_flow = ip6->ip6_flow;
PRT_SLOW_ARM(ip6f->ip6f_timer, IP6FLOW_TIMER);
ip6f->ip6f_start = time_uptime;
/*
* Insert into the approriate bucket of the flow table.
*/
hash = ip6flow_hash(ip6);
s = splnet();
IP6FLOW_INSERT(&ip6flowtable[hash], ip6f);
splx(s);
}
/*
* Invalidate/remove all flows - if new_size is positive we
* resize the hash table.
*/
int
ip6flow_invalidate_all(int new_size)
{
struct ip6flow *ip6f, *next_ip6f;
int s, error;
error = 0;
s = splnet();
for (ip6f = LIST_FIRST(&ip6flowlist); ip6f != NULL; ip6f = next_ip6f) {
next_ip6f = LIST_NEXT(ip6f, ip6f_list);
ip6flow_free(ip6f);
}
if (new_size)
error = ip6flow_init(new_size);
splx(s);
return error;
}