1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright (c) 2020 Alexander V. Chernikov
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25 * SUCH DAMAGE.
26 */
27
28 #include "opt_inet.h"
29 #include "opt_route.h"
30
31 #include <sys/param.h>
32 #include <sys/systm.h>
33 #include <sys/lock.h>
34 #include <sys/rmlock.h>
35 #include <sys/rwlock.h>
36 #include <sys/malloc.h>
37 #include <sys/mbuf.h>
38 #include <sys/refcount.h>
39 #include <sys/socket.h>
40 #include <sys/sysctl.h>
41 #include <sys/kernel.h>
42
43 #include <net/if.h>
44 #include <net/if_var.h>
45 #include <net/if_dl.h>
46 #include <net/route.h>
47 #include <net/route/route_ctl.h>
48 #include <net/route/route_var.h>
49 #include <net/vnet.h>
50
51 #include <netinet/in.h>
52 #include <netinet/in_var.h>
53 #include <netinet/in_fib.h>
54
55 #include <net/route/nhop_utils.h>
56 #include <net/route/nhop.h>
57 #include <net/route/nhop_var.h>
58 #include <net/route/nhgrp_var.h>
59
60 #define DEBUG_MOD_NAME nhgrp
61 #define DEBUG_MAX_LEVEL LOG_DEBUG
62 #include <net/route/route_debug.h>
63 _DECLARE_DEBUG(LOG_INFO);
64
65 /*
66 * This file contains data structures management logic for the nexthop
67 * groups ("nhgrp") route subsystem.
68 *
69 * Nexthop groups are used to store multiple routes available for the specific
70 * prefix. Nexthop groups are immutable and can be shared across multiple
71 * prefixes.
72 *
73 * Each group consists of a control plane part and a dataplane part.
74 * Control plane is basically a collection of nexthop objects with
75 * weights and refcount.
76 *
77 * Datapath consists of a array of nexthop pointers, compiled from control
78 * plane data to support O(1) nexthop selection.
79 *
80 * For example, consider the following group:
81 * [(nh1, weight=100), (nh2, weight=200)]
82 * It will compile to the following array:
83 * [nh1, nh2, nh2]
84 *
85 */
86
87 static void consider_resize(struct nh_control *ctl, uint32_t new_gr_buckets,
88 uint32_t new_idx_items);
89
90 static int cmp_nhgrp(const struct nhgrp_priv *a, const struct nhgrp_priv *b);
91 static unsigned int hash_nhgrp(const struct nhgrp_priv *obj);
92
93 static unsigned
djb_hash(const unsigned char * h,const int len)94 djb_hash(const unsigned char *h, const int len)
95 {
96 unsigned int result = 0;
97 int i;
98
99 for (i = 0; i < len; i++)
100 result = 33 * result ^ h[i];
101
102 return (result);
103 }
104
105 static int
cmp_nhgrp(const struct nhgrp_priv * a,const struct nhgrp_priv * b)106 cmp_nhgrp(const struct nhgrp_priv *a, const struct nhgrp_priv *b)
107 {
108
109 /*
110 * In case of consistent hashing, there can be multiple nexthop groups
111 * with the same "control plane" list of nexthops with weights and a
112 * different set of "data plane" nexthops.
113 * For now, ignore the data plane and focus on the control plane list.
114 */
115 if (a->nhg_nh_count != b->nhg_nh_count || a->nhg_uidx != b->nhg_uidx)
116 return (0);
117 return !memcmp(a->nhg_nh_weights, b->nhg_nh_weights,
118 sizeof(struct weightened_nhop) * a->nhg_nh_count);
119 }
120
121 /*
122 * Hash callback: calculate hash of an object
123 */
124 static unsigned int
hash_nhgrp(const struct nhgrp_priv * obj)125 hash_nhgrp(const struct nhgrp_priv *obj)
126 {
127 const unsigned char *key;
128
129 key = (const unsigned char *)obj->nhg_nh_weights;
130
131 return (djb_hash(key, sizeof(struct weightened_nhop) * obj->nhg_nh_count));
132 }
133
134 /*
135 * Returns object referenced and unlocked
136 */
137 struct nhgrp_priv *
find_nhgrp(struct nh_control * ctl,const struct nhgrp_priv * key)138 find_nhgrp(struct nh_control *ctl, const struct nhgrp_priv *key)
139 {
140 struct nhgrp_priv *priv_ret;
141
142 NHOPS_RLOCK(ctl);
143 CHT_SLIST_FIND_BYOBJ(&ctl->gr_head, mpath, key, priv_ret);
144 if (priv_ret != NULL) {
145 if (refcount_acquire_if_not_zero(&priv_ret->nhg_refcount) == 0) {
146 /* refcount is 0 -> group is being deleted */
147 priv_ret = NULL;
148 }
149 }
150 NHOPS_RUNLOCK(ctl);
151
152 return (priv_ret);
153 }
154
155 int
link_nhgrp(struct nh_control * ctl,struct nhgrp_priv * grp_priv)156 link_nhgrp(struct nh_control *ctl, struct nhgrp_priv *grp_priv)
157 {
158 uint16_t idx;
159 uint32_t new_num_buckets, new_num_items;
160
161 NHOPS_WLOCK(ctl);
162 /* Check if we need to resize hash and index */
163 new_num_buckets = CHT_SLIST_GET_RESIZE_BUCKETS(&ctl->gr_head);
164 new_num_items = bitmask_get_resize_items(&ctl->nh_idx_head);
165
166 if (bitmask_alloc_idx(&ctl->nh_idx_head, &idx) != 0) {
167 NHOPS_WUNLOCK(ctl);
168 FIB_RH_LOG(LOG_DEBUG, ctl->ctl_rh, "Unable to allocate nhg index");
169 consider_resize(ctl, new_num_buckets, new_num_items);
170 return (0);
171 }
172
173 grp_priv->nhg_idx = idx;
174 grp_priv->nh_control = ctl;
175 CHT_SLIST_INSERT_HEAD(&ctl->gr_head, mpath, grp_priv);
176
177 NHOPS_WUNLOCK(ctl);
178
179 IF_DEBUG_LEVEL(LOG_DEBUG2) {
180 char nhgrp_buf[NHOP_PRINT_BUFSIZE] __unused;
181 FIB_RH_LOG(LOG_DEBUG2, ctl->ctl_rh, "linked %s",
182 nhgrp_print_buf(grp_priv->nhg, nhgrp_buf, sizeof(nhgrp_buf)));
183 }
184 consider_resize(ctl, new_num_buckets, new_num_items);
185
186 return (1);
187 }
188
189 struct nhgrp_priv *
unlink_nhgrp(struct nh_control * ctl,struct nhgrp_priv * key)190 unlink_nhgrp(struct nh_control *ctl, struct nhgrp_priv *key)
191 {
192 struct nhgrp_priv *nhg_priv_ret;
193 int idx;
194
195 NHOPS_WLOCK(ctl);
196
197 CHT_SLIST_REMOVE(&ctl->gr_head, mpath, key, nhg_priv_ret);
198
199 if (nhg_priv_ret == NULL) {
200 FIB_RH_LOG(LOG_DEBUG, ctl->ctl_rh, "Unable to find nhg");
201 NHOPS_WUNLOCK(ctl);
202 return (NULL);
203 }
204
205 idx = nhg_priv_ret->nhg_idx;
206 bitmask_free_idx(&ctl->nh_idx_head, idx);
207 nhg_priv_ret->nhg_idx = 0;
208 nhg_priv_ret->nh_control = NULL;
209
210 NHOPS_WUNLOCK(ctl);
211
212 IF_DEBUG_LEVEL(LOG_DEBUG2) {
213 char nhgrp_buf[NHOP_PRINT_BUFSIZE];
214 nhgrp_print_buf(nhg_priv_ret->nhg, nhgrp_buf, sizeof(nhgrp_buf));
215 FIB_RH_LOG(LOG_DEBUG2, ctl->ctl_rh, "unlinked idx#%d %s", idx,
216 nhgrp_buf);
217 }
218
219 return (nhg_priv_ret);
220 }
221
222 /*
223 * Checks if hash needs resizing and performs this resize if necessary
224 *
225 */
226 static void
consider_resize(struct nh_control * ctl,uint32_t new_gr_bucket,uint32_t new_idx_items)227 consider_resize(struct nh_control *ctl, uint32_t new_gr_bucket, uint32_t new_idx_items)
228 {
229 void *gr_ptr, *gr_idx_ptr;
230 void *old_idx_ptr;
231 size_t alloc_size;
232
233 gr_ptr = NULL ;
234 if (new_gr_bucket != 0) {
235 alloc_size = CHT_SLIST_GET_RESIZE_SIZE(new_gr_bucket);
236 gr_ptr = malloc(alloc_size, M_NHOP, M_NOWAIT | M_ZERO);
237 }
238
239 gr_idx_ptr = NULL;
240 if (new_idx_items != 0) {
241 alloc_size = bitmask_get_size(new_idx_items);
242 gr_idx_ptr = malloc(alloc_size, M_NHOP, M_NOWAIT | M_ZERO);
243 }
244
245 if (gr_ptr == NULL && gr_idx_ptr == NULL) {
246 /* Either resize is not required or allocations have failed. */
247 return;
248 }
249
250 FIB_RH_LOG(LOG_DEBUG, ctl->ctl_rh,
251 "going to resize nhg hash: [ptr:%p sz:%u] idx:[ptr:%p sz:%u]",
252 gr_ptr, new_gr_bucket, gr_idx_ptr, new_idx_items);
253
254 old_idx_ptr = NULL;
255
256 NHOPS_WLOCK(ctl);
257 if (gr_ptr != NULL) {
258 CHT_SLIST_RESIZE(&ctl->gr_head, mpath, gr_ptr, new_gr_bucket);
259 }
260 if (gr_idx_ptr != NULL) {
261 if (bitmask_copy(&ctl->nh_idx_head, gr_idx_ptr, new_idx_items) == 0)
262 bitmask_swap(&ctl->nh_idx_head, gr_idx_ptr, new_idx_items, &old_idx_ptr);
263 }
264 NHOPS_WUNLOCK(ctl);
265
266 if (gr_ptr != NULL)
267 free(gr_ptr, M_NHOP);
268 if (old_idx_ptr != NULL)
269 free(old_idx_ptr, M_NHOP);
270 }
271
272 /*
273 * Function allocating the necessary group data structures.
274 */
275 bool
nhgrp_ctl_alloc_default(struct nh_control * ctl,int malloc_flags)276 nhgrp_ctl_alloc_default(struct nh_control *ctl, int malloc_flags)
277 {
278 size_t alloc_size;
279 uint32_t num_buckets;
280 void *cht_ptr;
281
282 malloc_flags = (malloc_flags & (M_NOWAIT | M_WAITOK)) | M_ZERO;
283
284 num_buckets = 8;
285 alloc_size = CHT_SLIST_GET_RESIZE_SIZE(num_buckets);
286 cht_ptr = malloc(alloc_size, M_NHOP, malloc_flags);
287
288 if (cht_ptr == NULL) {
289 FIB_RH_LOG(LOG_WARNING, ctl->ctl_rh, "multipath init failed");
290 return (false);
291 }
292
293 NHOPS_WLOCK(ctl);
294
295 if (ctl->gr_head.hash_size == 0) {
296 /* Init hash and bitmask */
297 CHT_SLIST_INIT(&ctl->gr_head, cht_ptr, num_buckets);
298 NHOPS_WUNLOCK(ctl);
299 } else {
300 /* Other thread has already initiliazed hash/bitmask */
301 NHOPS_WUNLOCK(ctl);
302 free(cht_ptr, M_NHOP);
303 }
304
305 FIB_RH_LOG(LOG_DEBUG, ctl->ctl_rh, "multipath init done");
306
307 return (true);
308 }
309
310 int
nhgrp_ctl_init(struct nh_control * ctl)311 nhgrp_ctl_init(struct nh_control *ctl)
312 {
313
314 /*
315 * By default, do not allocate datastructures as multipath
316 * routes will not be necessarily used.
317 */
318 CHT_SLIST_INIT(&ctl->gr_head, NULL, 0);
319 return (0);
320 }
321
322 void
nhgrp_ctl_free(struct nh_control * ctl)323 nhgrp_ctl_free(struct nh_control *ctl)
324 {
325 if (ctl->gr_head.ptr != NULL)
326 free(ctl->gr_head.ptr, M_NHOP);
327 }
328
329 void
nhgrp_ctl_unlink_all(struct nh_control * ctl)330 nhgrp_ctl_unlink_all(struct nh_control *ctl)
331 {
332 struct nhgrp_priv *nhg_priv;
333
334 NHOPS_WLOCK_ASSERT(ctl);
335
336 CHT_SLIST_FOREACH(&ctl->gr_head, mpath, nhg_priv) {
337 IF_DEBUG_LEVEL(LOG_DEBUG2) {
338 char nhgbuf[NHOP_PRINT_BUFSIZE] __unused;
339 FIB_RH_LOG(LOG_DEBUG2, ctl->ctl_rh, "marking %s unlinked",
340 nhgrp_print_buf(nhg_priv->nhg, nhgbuf, sizeof(nhgbuf)));
341 }
342 refcount_release(&nhg_priv->nhg_linked);
343 } CHT_SLIST_FOREACH_END;
344 }
345
346