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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
199int br_stp_set_enabled(struct net_bridge *br, unsigned long val,
200 struct netlink_ext_ack *extack)
201{
202 ASSERT_RTNL();
203
204 if (br_mrp_enabled(br)) {
205 NL_SET_ERR_MSG_MOD(extack,
206 "STP can't be enabled if MRP is already enabled");
207 return -EINVAL;
208 }
209
210 if (val) {
211 if (br->stp_enabled == BR_NO_STP)
212 br_stp_start(br);
213 } else {
214 if (br->stp_enabled != BR_NO_STP)
215 br_stp_stop(br);
216 }
217
218 return 0;
219}
220
221/* called under bridge lock */
222void br_stp_change_bridge_id(struct net_bridge *br, const unsigned char *addr)
223{
224 /* should be aligned on 2 bytes for ether_addr_equal() */
225 unsigned short oldaddr_aligned[ETH_ALEN >> 1];
226 unsigned char *oldaddr = (unsigned char *)oldaddr_aligned;
227 struct net_bridge_port *p;
228 int wasroot;
229
230 wasroot = br_is_root_bridge(br);
231
232 br_fdb_change_mac_address(br, addr);
233
234 memcpy(oldaddr, br->bridge_id.addr, ETH_ALEN);
235 memcpy(br->bridge_id.addr, addr, ETH_ALEN);
236 memcpy(br->dev->dev_addr, addr, ETH_ALEN);
237
238 list_for_each_entry(p, &br->port_list, list) {
239 if (ether_addr_equal(p->designated_bridge.addr, oldaddr))
240 memcpy(p->designated_bridge.addr, addr, ETH_ALEN);
241
242 if (ether_addr_equal(p->designated_root.addr, oldaddr))
243 memcpy(p->designated_root.addr, addr, ETH_ALEN);
244 }
245
246 br_configuration_update(br);
247 br_port_state_selection(br);
248 if (br_is_root_bridge(br) && !wasroot)
249 br_become_root_bridge(br);
250}
251
252/* should be aligned on 2 bytes for ether_addr_equal() */
253static const unsigned short br_mac_zero_aligned[ETH_ALEN >> 1];
254
255/* called under bridge lock */
256bool br_stp_recalculate_bridge_id(struct net_bridge *br)
257{
258 const unsigned char *br_mac_zero =
259 (const unsigned char *)br_mac_zero_aligned;
260 const unsigned char *addr = br_mac_zero;
261 struct net_bridge_port *p;
262
263 /* user has chosen a value so keep it */
264 if (br->dev->addr_assign_type == NET_ADDR_SET)
265 return false;
266
267 list_for_each_entry(p, &br->port_list, list) {
268 if (addr == br_mac_zero ||
269 memcmp(p->dev->dev_addr, addr, ETH_ALEN) < 0)
270 addr = p->dev->dev_addr;
271
272 }
273
274 if (ether_addr_equal(br->bridge_id.addr, addr))
275 return false; /* no change */
276
277 br_stp_change_bridge_id(br, addr);
278 return true;
279}
280
281/* Acquires and releases bridge lock */
282void br_stp_set_bridge_priority(struct net_bridge *br, u16 newprio)
283{
284 struct net_bridge_port *p;
285 int wasroot;
286
287 spin_lock_bh(&br->lock);
288 wasroot = br_is_root_bridge(br);
289
290 list_for_each_entry(p, &br->port_list, list) {
291 if (p->state != BR_STATE_DISABLED &&
292 br_is_designated_port(p)) {
293 p->designated_bridge.prio[0] = (newprio >> 8) & 0xFF;
294 p->designated_bridge.prio[1] = newprio & 0xFF;
295 }
296
297 }
298
299 br->bridge_id.prio[0] = (newprio >> 8) & 0xFF;
300 br->bridge_id.prio[1] = newprio & 0xFF;
301 br_configuration_update(br);
302 br_port_state_selection(br);
303 if (br_is_root_bridge(br) && !wasroot)
304 br_become_root_bridge(br);
305 spin_unlock_bh(&br->lock);
306}
307
308/* called under bridge lock */
309int br_stp_set_port_priority(struct net_bridge_port *p, unsigned long newprio)
310{
311 port_id new_port_id;
312
313 if (newprio > BR_MAX_PORT_PRIORITY)
314 return -ERANGE;
315
316 new_port_id = br_make_port_id(newprio, p->port_no);
317 if (br_is_designated_port(p))
318 p->designated_port = new_port_id;
319
320 p->port_id = new_port_id;
321 p->priority = newprio;
322 if (!memcmp(&p->br->bridge_id, &p->designated_bridge, 8) &&
323 p->port_id < p->designated_port) {
324 br_become_designated_port(p);
325 br_port_state_selection(p->br);
326 }
327
328 return 0;
329}
330
331/* called under bridge lock */
332int br_stp_set_path_cost(struct net_bridge_port *p, unsigned long path_cost)
333{
334 if (path_cost < BR_MIN_PATH_COST ||
335 path_cost > BR_MAX_PATH_COST)
336 return -ERANGE;
337
338 p->flags |= BR_ADMIN_COST;
339 p->path_cost = path_cost;
340 br_configuration_update(p->br);
341 br_port_state_selection(p->br);
342 return 0;
343}
344
345ssize_t br_show_bridge_id(char *buf, const struct bridge_id *id)
346{
347 return sprintf(buf, "%.2x%.2x.%.2x%.2x%.2x%.2x%.2x%.2x\n",
348 id->prio[0], id->prio[1],
349 id->addr[0], id->addr[1], id->addr[2],
350 id->addr[3], id->addr[4], id->addr[5]);
351}
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_timer(&br->gc_timer, jiffies + 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 del_timer_sync(&br->gc_timer);
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, 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, 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 struct net_bridge_port *p;
154 int err = -ENOENT;
155
156 if (net_eq(dev_net(br->dev), &init_net))
157 err = br_stp_call_user(br, "start");
158
159 if (err && err != -ENOENT)
160 br_err(br, "failed to start userspace STP (%d)\n", err);
161
162 spin_lock_bh(&br->lock);
163
164 if (br->bridge_forward_delay < BR_MIN_FORWARD_DELAY)
165 __br_set_forward_delay(br, BR_MIN_FORWARD_DELAY);
166 else if (br->bridge_forward_delay > BR_MAX_FORWARD_DELAY)
167 __br_set_forward_delay(br, BR_MAX_FORWARD_DELAY);
168
169 if (!err) {
170 br->stp_enabled = BR_USER_STP;
171 br_debug(br, "userspace STP started\n");
172
173 /* Stop hello and hold timers */
174 del_timer(&br->hello_timer);
175 list_for_each_entry(p, &br->port_list, list)
176 del_timer(&p->hold_timer);
177 } else {
178 br->stp_enabled = BR_KERNEL_STP;
179 br_debug(br, "using kernel STP\n");
180
181 /* To start timers on any ports left in blocking */
182 br_port_state_selection(br);
183 }
184
185 spin_unlock_bh(&br->lock);
186}
187
188static void br_stp_stop(struct net_bridge *br)
189{
190 struct net_bridge_port *p;
191 int err;
192
193 if (br->stp_enabled == BR_USER_STP) {
194 err = br_stp_call_user(br, "stop");
195 if (err)
196 br_err(br, "failed to stop userspace STP (%d)\n", err);
197
198 /* To start timers on any ports left in blocking */
199 mod_timer(&br->hello_timer, jiffies + br->hello_time);
200 list_for_each_entry(p, &br->port_list, list)
201 mod_timer(&p->hold_timer,
202 round_jiffies(jiffies + BR_HOLD_TIME));
203 spin_lock_bh(&br->lock);
204 br_port_state_selection(br);
205 spin_unlock_bh(&br->lock);
206 }
207
208 br->stp_enabled = BR_NO_STP;
209}
210
211void br_stp_set_enabled(struct net_bridge *br, unsigned long val)
212{
213 ASSERT_RTNL();
214
215 if (val) {
216 if (br->stp_enabled == BR_NO_STP)
217 br_stp_start(br);
218 } else {
219 if (br->stp_enabled != BR_NO_STP)
220 br_stp_stop(br);
221 }
222}
223
224/* called under bridge lock */
225void br_stp_change_bridge_id(struct net_bridge *br, const unsigned char *addr)
226{
227 /* should be aligned on 2 bytes for ether_addr_equal() */
228 unsigned short oldaddr_aligned[ETH_ALEN >> 1];
229 unsigned char *oldaddr = (unsigned char *)oldaddr_aligned;
230 struct net_bridge_port *p;
231 int wasroot;
232
233 wasroot = br_is_root_bridge(br);
234
235 br_fdb_change_mac_address(br, addr);
236
237 memcpy(oldaddr, br->bridge_id.addr, ETH_ALEN);
238 memcpy(br->bridge_id.addr, addr, ETH_ALEN);
239 memcpy(br->dev->dev_addr, addr, ETH_ALEN);
240
241 list_for_each_entry(p, &br->port_list, list) {
242 if (ether_addr_equal(p->designated_bridge.addr, oldaddr))
243 memcpy(p->designated_bridge.addr, addr, ETH_ALEN);
244
245 if (ether_addr_equal(p->designated_root.addr, oldaddr))
246 memcpy(p->designated_root.addr, addr, ETH_ALEN);
247 }
248
249 br_configuration_update(br);
250 br_port_state_selection(br);
251 if (br_is_root_bridge(br) && !wasroot)
252 br_become_root_bridge(br);
253}
254
255/* should be aligned on 2 bytes for ether_addr_equal() */
256static const unsigned short br_mac_zero_aligned[ETH_ALEN >> 1];
257
258/* called under bridge lock */
259bool br_stp_recalculate_bridge_id(struct net_bridge *br)
260{
261 const unsigned char *br_mac_zero =
262 (const unsigned char *)br_mac_zero_aligned;
263 const unsigned char *addr = br_mac_zero;
264 struct net_bridge_port *p;
265
266 /* user has chosen a value so keep it */
267 if (br->dev->addr_assign_type == NET_ADDR_SET)
268 return false;
269
270 list_for_each_entry(p, &br->port_list, list) {
271 if (addr == br_mac_zero ||
272 memcmp(p->dev->dev_addr, addr, ETH_ALEN) < 0)
273 addr = p->dev->dev_addr;
274
275 }
276
277 if (ether_addr_equal(br->bridge_id.addr, addr))
278 return false; /* no change */
279
280 br_stp_change_bridge_id(br, addr);
281 return true;
282}
283
284/* Acquires and releases bridge lock */
285void br_stp_set_bridge_priority(struct net_bridge *br, u16 newprio)
286{
287 struct net_bridge_port *p;
288 int wasroot;
289
290 spin_lock_bh(&br->lock);
291 wasroot = br_is_root_bridge(br);
292
293 list_for_each_entry(p, &br->port_list, list) {
294 if (p->state != BR_STATE_DISABLED &&
295 br_is_designated_port(p)) {
296 p->designated_bridge.prio[0] = (newprio >> 8) & 0xFF;
297 p->designated_bridge.prio[1] = newprio & 0xFF;
298 }
299
300 }
301
302 br->bridge_id.prio[0] = (newprio >> 8) & 0xFF;
303 br->bridge_id.prio[1] = newprio & 0xFF;
304 br_configuration_update(br);
305 br_port_state_selection(br);
306 if (br_is_root_bridge(br) && !wasroot)
307 br_become_root_bridge(br);
308 spin_unlock_bh(&br->lock);
309}
310
311/* called under bridge lock */
312int br_stp_set_port_priority(struct net_bridge_port *p, unsigned long newprio)
313{
314 port_id new_port_id;
315
316 if (newprio > BR_MAX_PORT_PRIORITY)
317 return -ERANGE;
318
319 new_port_id = br_make_port_id(newprio, p->port_no);
320 if (br_is_designated_port(p))
321 p->designated_port = new_port_id;
322
323 p->port_id = new_port_id;
324 p->priority = newprio;
325 if (!memcmp(&p->br->bridge_id, &p->designated_bridge, 8) &&
326 p->port_id < p->designated_port) {
327 br_become_designated_port(p);
328 br_port_state_selection(p->br);
329 }
330
331 return 0;
332}
333
334/* called under bridge lock */
335int br_stp_set_path_cost(struct net_bridge_port *p, unsigned long path_cost)
336{
337 if (path_cost < BR_MIN_PATH_COST ||
338 path_cost > BR_MAX_PATH_COST)
339 return -ERANGE;
340
341 p->flags |= BR_ADMIN_COST;
342 p->path_cost = path_cost;
343 br_configuration_update(p->br);
344 br_port_state_selection(p->br);
345 return 0;
346}
347
348ssize_t br_show_bridge_id(char *buf, const struct bridge_id *id)
349{
350 return sprintf(buf, "%.2x%.2x.%.2x%.2x%.2x%.2x%.2x%.2x\n",
351 id->prio[0], id->prio[1],
352 id->addr[0], id->addr[1], id->addr[2],
353 id->addr[3], id->addr[4], id->addr[5]);
354}