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1/*
2 * Spanning tree protocol; interface code
3 * Linux ethernet bridge
4 *
5 * Authors:
6 * Lennert Buytenhek <buytenh@gnu.org>
7 *
8 * This program is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU General Public License
10 * as published by the Free Software Foundation; either version
11 * 2 of the License, or (at your option) any later version.
12 */
13
14#include <linux/kernel.h>
15#include <linux/kmod.h>
16#include <linux/etherdevice.h>
17#include <linux/rtnetlink.h>
18#include <net/switchdev.h>
19
20#include "br_private.h"
21#include "br_private_stp.h"
22
23
24/* Port id is composed of priority and port number.
25 * NB: some bits of priority are dropped to
26 * make room for more ports.
27 */
28static inline port_id br_make_port_id(__u8 priority, __u16 port_no)
29{
30 return ((u16)priority << BR_PORT_BITS)
31 | (port_no & ((1<<BR_PORT_BITS)-1));
32}
33
34#define BR_MAX_PORT_PRIORITY ((u16)~0 >> BR_PORT_BITS)
35
36/* called under bridge lock */
37void br_init_port(struct net_bridge_port *p)
38{
39 int err;
40
41 p->port_id = br_make_port_id(p->priority, p->port_no);
42 br_become_designated_port(p);
43 br_set_state(p, BR_STATE_BLOCKING);
44 p->topology_change_ack = 0;
45 p->config_pending = 0;
46
47 err = __set_ageing_time(p->dev, p->br->ageing_time);
48 if (err)
49 netdev_err(p->dev, "failed to offload ageing time\n");
50}
51
52/* NO locks held */
53void br_stp_enable_bridge(struct net_bridge *br)
54{
55 struct net_bridge_port *p;
56
57 spin_lock_bh(&br->lock);
58 if (br->stp_enabled == BR_KERNEL_STP)
59 mod_timer(&br->hello_timer, jiffies + br->hello_time);
60 mod_delayed_work(system_long_wq, &br->gc_work, HZ / 10);
61
62 br_config_bpdu_generation(br);
63
64 list_for_each_entry(p, &br->port_list, list) {
65 if (netif_running(p->dev) && netif_oper_up(p->dev))
66 br_stp_enable_port(p);
67
68 }
69 spin_unlock_bh(&br->lock);
70}
71
72/* NO locks held */
73void br_stp_disable_bridge(struct net_bridge *br)
74{
75 struct net_bridge_port *p;
76
77 spin_lock_bh(&br->lock);
78 list_for_each_entry(p, &br->port_list, list) {
79 if (p->state != BR_STATE_DISABLED)
80 br_stp_disable_port(p);
81
82 }
83
84 __br_set_topology_change(br, 0);
85 br->topology_change_detected = 0;
86 spin_unlock_bh(&br->lock);
87
88 del_timer_sync(&br->hello_timer);
89 del_timer_sync(&br->topology_change_timer);
90 del_timer_sync(&br->tcn_timer);
91 cancel_delayed_work_sync(&br->gc_work);
92}
93
94/* called under bridge lock */
95void br_stp_enable_port(struct net_bridge_port *p)
96{
97 br_init_port(p);
98 br_port_state_selection(p->br);
99 br_ifinfo_notify(RTM_NEWLINK, NULL, p);
100}
101
102/* called under bridge lock */
103void br_stp_disable_port(struct net_bridge_port *p)
104{
105 struct net_bridge *br = p->br;
106 int wasroot;
107
108 wasroot = br_is_root_bridge(br);
109 br_become_designated_port(p);
110 br_set_state(p, BR_STATE_DISABLED);
111 p->topology_change_ack = 0;
112 p->config_pending = 0;
113
114 br_ifinfo_notify(RTM_NEWLINK, NULL, p);
115
116 del_timer(&p->message_age_timer);
117 del_timer(&p->forward_delay_timer);
118 del_timer(&p->hold_timer);
119
120 br_fdb_delete_by_port(br, p, 0, 0);
121 br_multicast_disable_port(p);
122
123 br_configuration_update(br);
124
125 br_port_state_selection(br);
126
127 if (br_is_root_bridge(br) && !wasroot)
128 br_become_root_bridge(br);
129}
130
131static int br_stp_call_user(struct net_bridge *br, char *arg)
132{
133 char *argv[] = { BR_STP_PROG, br->dev->name, arg, NULL };
134 char *envp[] = { NULL };
135 int rc;
136
137 /* call userspace STP and report program errors */
138 rc = call_usermodehelper(BR_STP_PROG, argv, envp, UMH_WAIT_PROC);
139 if (rc > 0) {
140 if (rc & 0xff)
141 br_debug(br, BR_STP_PROG " received signal %d\n",
142 rc & 0x7f);
143 else
144 br_debug(br, BR_STP_PROG " exited with code %d\n",
145 (rc >> 8) & 0xff);
146 }
147
148 return rc;
149}
150
151static void br_stp_start(struct net_bridge *br)
152{
153 int err = -ENOENT;
154
155 if (net_eq(dev_net(br->dev), &init_net))
156 err = br_stp_call_user(br, "start");
157
158 if (err && err != -ENOENT)
159 br_err(br, "failed to start userspace STP (%d)\n", err);
160
161 spin_lock_bh(&br->lock);
162
163 if (br->bridge_forward_delay < BR_MIN_FORWARD_DELAY)
164 __br_set_forward_delay(br, BR_MIN_FORWARD_DELAY);
165 else if (br->bridge_forward_delay > BR_MAX_FORWARD_DELAY)
166 __br_set_forward_delay(br, BR_MAX_FORWARD_DELAY);
167
168 if (!err) {
169 br->stp_enabled = BR_USER_STP;
170 br_debug(br, "userspace STP started\n");
171 } else {
172 br->stp_enabled = BR_KERNEL_STP;
173 br_debug(br, "using kernel STP\n");
174
175 /* To start timers on any ports left in blocking */
176 if (br->dev->flags & IFF_UP)
177 mod_timer(&br->hello_timer, jiffies + br->hello_time);
178 br_port_state_selection(br);
179 }
180
181 spin_unlock_bh(&br->lock);
182}
183
184static void br_stp_stop(struct net_bridge *br)
185{
186 int err;
187
188 if (br->stp_enabled == BR_USER_STP) {
189 err = br_stp_call_user(br, "stop");
190 if (err)
191 br_err(br, "failed to stop userspace STP (%d)\n", err);
192
193 /* To start timers on any ports left in blocking */
194 spin_lock_bh(&br->lock);
195 br_port_state_selection(br);
196 spin_unlock_bh(&br->lock);
197 }
198
199 br->stp_enabled = BR_NO_STP;
200}
201
202void br_stp_set_enabled(struct net_bridge *br, unsigned long val)
203{
204 ASSERT_RTNL();
205
206 if (val) {
207 if (br->stp_enabled == BR_NO_STP)
208 br_stp_start(br);
209 } else {
210 if (br->stp_enabled != BR_NO_STP)
211 br_stp_stop(br);
212 }
213}
214
215/* called under bridge lock */
216void br_stp_change_bridge_id(struct net_bridge *br, const unsigned char *addr)
217{
218 /* should be aligned on 2 bytes for ether_addr_equal() */
219 unsigned short oldaddr_aligned[ETH_ALEN >> 1];
220 unsigned char *oldaddr = (unsigned char *)oldaddr_aligned;
221 struct net_bridge_port *p;
222 int wasroot;
223
224 wasroot = br_is_root_bridge(br);
225
226 br_fdb_change_mac_address(br, addr);
227
228 memcpy(oldaddr, br->bridge_id.addr, ETH_ALEN);
229 memcpy(br->bridge_id.addr, addr, ETH_ALEN);
230 memcpy(br->dev->dev_addr, addr, ETH_ALEN);
231
232 list_for_each_entry(p, &br->port_list, list) {
233 if (ether_addr_equal(p->designated_bridge.addr, oldaddr))
234 memcpy(p->designated_bridge.addr, addr, ETH_ALEN);
235
236 if (ether_addr_equal(p->designated_root.addr, oldaddr))
237 memcpy(p->designated_root.addr, addr, ETH_ALEN);
238 }
239
240 br_configuration_update(br);
241 br_port_state_selection(br);
242 if (br_is_root_bridge(br) && !wasroot)
243 br_become_root_bridge(br);
244}
245
246/* should be aligned on 2 bytes for ether_addr_equal() */
247static const unsigned short br_mac_zero_aligned[ETH_ALEN >> 1];
248
249/* called under bridge lock */
250bool br_stp_recalculate_bridge_id(struct net_bridge *br)
251{
252 const unsigned char *br_mac_zero =
253 (const unsigned char *)br_mac_zero_aligned;
254 const unsigned char *addr = br_mac_zero;
255 struct net_bridge_port *p;
256
257 /* user has chosen a value so keep it */
258 if (br->dev->addr_assign_type == NET_ADDR_SET)
259 return false;
260
261 list_for_each_entry(p, &br->port_list, list) {
262 if (addr == br_mac_zero ||
263 memcmp(p->dev->dev_addr, addr, ETH_ALEN) < 0)
264 addr = p->dev->dev_addr;
265
266 }
267
268 if (ether_addr_equal(br->bridge_id.addr, addr))
269 return false; /* no change */
270
271 br_stp_change_bridge_id(br, addr);
272 return true;
273}
274
275/* Acquires and releases bridge lock */
276void br_stp_set_bridge_priority(struct net_bridge *br, u16 newprio)
277{
278 struct net_bridge_port *p;
279 int wasroot;
280
281 spin_lock_bh(&br->lock);
282 wasroot = br_is_root_bridge(br);
283
284 list_for_each_entry(p, &br->port_list, list) {
285 if (p->state != BR_STATE_DISABLED &&
286 br_is_designated_port(p)) {
287 p->designated_bridge.prio[0] = (newprio >> 8) & 0xFF;
288 p->designated_bridge.prio[1] = newprio & 0xFF;
289 }
290
291 }
292
293 br->bridge_id.prio[0] = (newprio >> 8) & 0xFF;
294 br->bridge_id.prio[1] = newprio & 0xFF;
295 br_configuration_update(br);
296 br_port_state_selection(br);
297 if (br_is_root_bridge(br) && !wasroot)
298 br_become_root_bridge(br);
299 spin_unlock_bh(&br->lock);
300}
301
302/* called under bridge lock */
303int br_stp_set_port_priority(struct net_bridge_port *p, unsigned long newprio)
304{
305 port_id new_port_id;
306
307 if (newprio > BR_MAX_PORT_PRIORITY)
308 return -ERANGE;
309
310 new_port_id = br_make_port_id(newprio, p->port_no);
311 if (br_is_designated_port(p))
312 p->designated_port = new_port_id;
313
314 p->port_id = new_port_id;
315 p->priority = newprio;
316 if (!memcmp(&p->br->bridge_id, &p->designated_bridge, 8) &&
317 p->port_id < p->designated_port) {
318 br_become_designated_port(p);
319 br_port_state_selection(p->br);
320 }
321
322 return 0;
323}
324
325/* called under bridge lock */
326int br_stp_set_path_cost(struct net_bridge_port *p, unsigned long path_cost)
327{
328 if (path_cost < BR_MIN_PATH_COST ||
329 path_cost > BR_MAX_PATH_COST)
330 return -ERANGE;
331
332 p->flags |= BR_ADMIN_COST;
333 p->path_cost = path_cost;
334 br_configuration_update(p->br);
335 br_port_state_selection(p->br);
336 return 0;
337}
338
339ssize_t br_show_bridge_id(char *buf, const struct bridge_id *id)
340{
341 return sprintf(buf, "%.2x%.2x.%.2x%.2x%.2x%.2x%.2x%.2x\n",
342 id->prio[0], id->prio[1],
343 id->addr[0], id->addr[1], id->addr[2],
344 id->addr[3], id->addr[4], id->addr[5]);
345}
1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Spanning tree protocol; interface code
4 * Linux ethernet bridge
5 *
6 * Authors:
7 * Lennert Buytenhek <buytenh@gnu.org>
8 */
9
10#include <linux/kernel.h>
11#include <linux/kmod.h>
12#include <linux/etherdevice.h>
13#include <linux/rtnetlink.h>
14#include <net/switchdev.h>
15
16#include "br_private.h"
17#include "br_private_stp.h"
18
19
20/* Port id is composed of priority and port number.
21 * NB: some bits of priority are dropped to
22 * make room for more ports.
23 */
24static inline port_id br_make_port_id(__u8 priority, __u16 port_no)
25{
26 return ((u16)priority << BR_PORT_BITS)
27 | (port_no & ((1<<BR_PORT_BITS)-1));
28}
29
30#define BR_MAX_PORT_PRIORITY ((u16)~0 >> BR_PORT_BITS)
31
32/* called under bridge lock */
33void br_init_port(struct net_bridge_port *p)
34{
35 int err;
36
37 p->port_id = br_make_port_id(p->priority, p->port_no);
38 br_become_designated_port(p);
39 br_set_state(p, BR_STATE_BLOCKING);
40 p->topology_change_ack = 0;
41 p->config_pending = 0;
42
43 err = __set_ageing_time(p->dev, p->br->ageing_time);
44 if (err)
45 netdev_err(p->dev, "failed to offload ageing time\n");
46}
47
48/* NO locks held */
49void br_stp_enable_bridge(struct net_bridge *br)
50{
51 struct net_bridge_port *p;
52
53 spin_lock_bh(&br->lock);
54 if (br->stp_enabled == BR_KERNEL_STP)
55 mod_timer(&br->hello_timer, jiffies + br->hello_time);
56 mod_delayed_work(system_long_wq, &br->gc_work, HZ / 10);
57
58 br_config_bpdu_generation(br);
59
60 list_for_each_entry(p, &br->port_list, list) {
61 if (netif_running(p->dev) && netif_oper_up(p->dev))
62 br_stp_enable_port(p);
63
64 }
65 spin_unlock_bh(&br->lock);
66}
67
68/* NO locks held */
69void br_stp_disable_bridge(struct net_bridge *br)
70{
71 struct net_bridge_port *p;
72
73 spin_lock_bh(&br->lock);
74 list_for_each_entry(p, &br->port_list, list) {
75 if (p->state != BR_STATE_DISABLED)
76 br_stp_disable_port(p);
77
78 }
79
80 __br_set_topology_change(br, 0);
81 br->topology_change_detected = 0;
82 spin_unlock_bh(&br->lock);
83
84 del_timer_sync(&br->hello_timer);
85 del_timer_sync(&br->topology_change_timer);
86 del_timer_sync(&br->tcn_timer);
87 cancel_delayed_work_sync(&br->gc_work);
88}
89
90/* called under bridge lock */
91void br_stp_enable_port(struct net_bridge_port *p)
92{
93 br_init_port(p);
94 br_port_state_selection(p->br);
95 br_ifinfo_notify(RTM_NEWLINK, NULL, p);
96}
97
98/* called under bridge lock */
99void br_stp_disable_port(struct net_bridge_port *p)
100{
101 struct net_bridge *br = p->br;
102 int wasroot;
103
104 wasroot = br_is_root_bridge(br);
105 br_become_designated_port(p);
106 br_set_state(p, BR_STATE_DISABLED);
107 p->topology_change_ack = 0;
108 p->config_pending = 0;
109
110 br_ifinfo_notify(RTM_NEWLINK, NULL, p);
111
112 del_timer(&p->message_age_timer);
113 del_timer(&p->forward_delay_timer);
114 del_timer(&p->hold_timer);
115
116 if (!rcu_access_pointer(p->backup_port))
117 br_fdb_delete_by_port(br, p, 0, 0);
118 br_multicast_disable_port(p);
119
120 br_configuration_update(br);
121
122 br_port_state_selection(br);
123
124 if (br_is_root_bridge(br) && !wasroot)
125 br_become_root_bridge(br);
126}
127
128static int br_stp_call_user(struct net_bridge *br, char *arg)
129{
130 char *argv[] = { BR_STP_PROG, br->dev->name, arg, NULL };
131 char *envp[] = { NULL };
132 int rc;
133
134 /* call userspace STP and report program errors */
135 rc = call_usermodehelper(BR_STP_PROG, argv, envp, UMH_WAIT_PROC);
136 if (rc > 0) {
137 if (rc & 0xff)
138 br_debug(br, BR_STP_PROG " received signal %d\n",
139 rc & 0x7f);
140 else
141 br_debug(br, BR_STP_PROG " exited with code %d\n",
142 (rc >> 8) & 0xff);
143 }
144
145 return rc;
146}
147
148static void br_stp_start(struct net_bridge *br)
149{
150 int err = -ENOENT;
151
152 if (net_eq(dev_net(br->dev), &init_net))
153 err = br_stp_call_user(br, "start");
154
155 if (err && err != -ENOENT)
156 br_err(br, "failed to start userspace STP (%d)\n", err);
157
158 spin_lock_bh(&br->lock);
159
160 if (br->bridge_forward_delay < BR_MIN_FORWARD_DELAY)
161 __br_set_forward_delay(br, BR_MIN_FORWARD_DELAY);
162 else if (br->bridge_forward_delay > BR_MAX_FORWARD_DELAY)
163 __br_set_forward_delay(br, BR_MAX_FORWARD_DELAY);
164
165 if (!err) {
166 br->stp_enabled = BR_USER_STP;
167 br_debug(br, "userspace STP started\n");
168 } else {
169 br->stp_enabled = BR_KERNEL_STP;
170 br_debug(br, "using kernel STP\n");
171
172 /* To start timers on any ports left in blocking */
173 if (br->dev->flags & IFF_UP)
174 mod_timer(&br->hello_timer, jiffies + br->hello_time);
175 br_port_state_selection(br);
176 }
177
178 spin_unlock_bh(&br->lock);
179}
180
181static void br_stp_stop(struct net_bridge *br)
182{
183 int err;
184
185 if (br->stp_enabled == BR_USER_STP) {
186 err = br_stp_call_user(br, "stop");
187 if (err)
188 br_err(br, "failed to stop userspace STP (%d)\n", err);
189
190 /* To start timers on any ports left in blocking */
191 spin_lock_bh(&br->lock);
192 br_port_state_selection(br);
193 spin_unlock_bh(&br->lock);
194 }
195
196 br->stp_enabled = BR_NO_STP;
197}
198
199void br_stp_set_enabled(struct net_bridge *br, unsigned long val)
200{
201 ASSERT_RTNL();
202
203 if (val) {
204 if (br->stp_enabled == BR_NO_STP)
205 br_stp_start(br);
206 } else {
207 if (br->stp_enabled != BR_NO_STP)
208 br_stp_stop(br);
209 }
210}
211
212/* called under bridge lock */
213void br_stp_change_bridge_id(struct net_bridge *br, const unsigned char *addr)
214{
215 /* should be aligned on 2 bytes for ether_addr_equal() */
216 unsigned short oldaddr_aligned[ETH_ALEN >> 1];
217 unsigned char *oldaddr = (unsigned char *)oldaddr_aligned;
218 struct net_bridge_port *p;
219 int wasroot;
220
221 wasroot = br_is_root_bridge(br);
222
223 br_fdb_change_mac_address(br, addr);
224
225 memcpy(oldaddr, br->bridge_id.addr, ETH_ALEN);
226 memcpy(br->bridge_id.addr, addr, ETH_ALEN);
227 memcpy(br->dev->dev_addr, addr, ETH_ALEN);
228
229 list_for_each_entry(p, &br->port_list, list) {
230 if (ether_addr_equal(p->designated_bridge.addr, oldaddr))
231 memcpy(p->designated_bridge.addr, addr, ETH_ALEN);
232
233 if (ether_addr_equal(p->designated_root.addr, oldaddr))
234 memcpy(p->designated_root.addr, addr, ETH_ALEN);
235 }
236
237 br_configuration_update(br);
238 br_port_state_selection(br);
239 if (br_is_root_bridge(br) && !wasroot)
240 br_become_root_bridge(br);
241}
242
243/* should be aligned on 2 bytes for ether_addr_equal() */
244static const unsigned short br_mac_zero_aligned[ETH_ALEN >> 1];
245
246/* called under bridge lock */
247bool br_stp_recalculate_bridge_id(struct net_bridge *br)
248{
249 const unsigned char *br_mac_zero =
250 (const unsigned char *)br_mac_zero_aligned;
251 const unsigned char *addr = br_mac_zero;
252 struct net_bridge_port *p;
253
254 /* user has chosen a value so keep it */
255 if (br->dev->addr_assign_type == NET_ADDR_SET)
256 return false;
257
258 list_for_each_entry(p, &br->port_list, list) {
259 if (addr == br_mac_zero ||
260 memcmp(p->dev->dev_addr, addr, ETH_ALEN) < 0)
261 addr = p->dev->dev_addr;
262
263 }
264
265 if (ether_addr_equal(br->bridge_id.addr, addr))
266 return false; /* no change */
267
268 br_stp_change_bridge_id(br, addr);
269 return true;
270}
271
272/* Acquires and releases bridge lock */
273void br_stp_set_bridge_priority(struct net_bridge *br, u16 newprio)
274{
275 struct net_bridge_port *p;
276 int wasroot;
277
278 spin_lock_bh(&br->lock);
279 wasroot = br_is_root_bridge(br);
280
281 list_for_each_entry(p, &br->port_list, list) {
282 if (p->state != BR_STATE_DISABLED &&
283 br_is_designated_port(p)) {
284 p->designated_bridge.prio[0] = (newprio >> 8) & 0xFF;
285 p->designated_bridge.prio[1] = newprio & 0xFF;
286 }
287
288 }
289
290 br->bridge_id.prio[0] = (newprio >> 8) & 0xFF;
291 br->bridge_id.prio[1] = newprio & 0xFF;
292 br_configuration_update(br);
293 br_port_state_selection(br);
294 if (br_is_root_bridge(br) && !wasroot)
295 br_become_root_bridge(br);
296 spin_unlock_bh(&br->lock);
297}
298
299/* called under bridge lock */
300int br_stp_set_port_priority(struct net_bridge_port *p, unsigned long newprio)
301{
302 port_id new_port_id;
303
304 if (newprio > BR_MAX_PORT_PRIORITY)
305 return -ERANGE;
306
307 new_port_id = br_make_port_id(newprio, p->port_no);
308 if (br_is_designated_port(p))
309 p->designated_port = new_port_id;
310
311 p->port_id = new_port_id;
312 p->priority = newprio;
313 if (!memcmp(&p->br->bridge_id, &p->designated_bridge, 8) &&
314 p->port_id < p->designated_port) {
315 br_become_designated_port(p);
316 br_port_state_selection(p->br);
317 }
318
319 return 0;
320}
321
322/* called under bridge lock */
323int br_stp_set_path_cost(struct net_bridge_port *p, unsigned long path_cost)
324{
325 if (path_cost < BR_MIN_PATH_COST ||
326 path_cost > BR_MAX_PATH_COST)
327 return -ERANGE;
328
329 p->flags |= BR_ADMIN_COST;
330 p->path_cost = path_cost;
331 br_configuration_update(p->br);
332 br_port_state_selection(p->br);
333 return 0;
334}
335
336ssize_t br_show_bridge_id(char *buf, const struct bridge_id *id)
337{
338 return sprintf(buf, "%.2x%.2x.%.2x%.2x%.2x%.2x%.2x%.2x\n",
339 id->prio[0], id->prio[1],
340 id->addr[0], id->addr[1], id->addr[2],
341 id->addr[3], id->addr[4], id->addr[5]);
342}