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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
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}
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
19#include "br_private.h"
20#include "br_private_stp.h"
21
22
23/* Port id is composed of priority and port number.
24 * NB: some bits of priority are dropped to
25 * make room for more ports.
26 */
27static inline port_id br_make_port_id(__u8 priority, __u16 port_no)
28{
29 return ((u16)priority << BR_PORT_BITS)
30 | (port_no & ((1<<BR_PORT_BITS)-1));
31}
32
33#define BR_MAX_PORT_PRIORITY ((u16)~0 >> BR_PORT_BITS)
34
35/* called under bridge lock */
36void br_init_port(struct net_bridge_port *p)
37{
38 p->port_id = br_make_port_id(p->priority, p->port_no);
39 br_become_designated_port(p);
40 p->state = BR_STATE_BLOCKING;
41 p->topology_change_ack = 0;
42 p->config_pending = 0;
43}
44
45/* called under bridge lock */
46void br_stp_enable_bridge(struct net_bridge *br)
47{
48 struct net_bridge_port *p;
49
50 spin_lock_bh(&br->lock);
51 mod_timer(&br->hello_timer, jiffies + br->hello_time);
52 mod_timer(&br->gc_timer, jiffies + HZ/10);
53
54 br_config_bpdu_generation(br);
55
56 list_for_each_entry(p, &br->port_list, list) {
57 if (netif_running(p->dev) && netif_oper_up(p->dev))
58 br_stp_enable_port(p);
59
60 }
61 spin_unlock_bh(&br->lock);
62}
63
64/* NO locks held */
65void br_stp_disable_bridge(struct net_bridge *br)
66{
67 struct net_bridge_port *p;
68
69 spin_lock_bh(&br->lock);
70 list_for_each_entry(p, &br->port_list, list) {
71 if (p->state != BR_STATE_DISABLED)
72 br_stp_disable_port(p);
73
74 }
75
76 br->topology_change = 0;
77 br->topology_change_detected = 0;
78 spin_unlock_bh(&br->lock);
79
80 del_timer_sync(&br->hello_timer);
81 del_timer_sync(&br->topology_change_timer);
82 del_timer_sync(&br->tcn_timer);
83 del_timer_sync(&br->gc_timer);
84}
85
86/* called under bridge lock */
87void br_stp_enable_port(struct net_bridge_port *p)
88{
89 br_init_port(p);
90 br_port_state_selection(p->br);
91 br_log_state(p);
92 br_ifinfo_notify(RTM_NEWLINK, p);
93}
94
95/* called under bridge lock */
96void br_stp_disable_port(struct net_bridge_port *p)
97{
98 struct net_bridge *br = p->br;
99 int wasroot;
100
101 wasroot = br_is_root_bridge(br);
102 br_become_designated_port(p);
103 p->state = BR_STATE_DISABLED;
104 p->topology_change_ack = 0;
105 p->config_pending = 0;
106
107 br_log_state(p);
108 br_ifinfo_notify(RTM_NEWLINK, p);
109
110 del_timer(&p->message_age_timer);
111 del_timer(&p->forward_delay_timer);
112 del_timer(&p->hold_timer);
113
114 br_fdb_delete_by_port(br, p, 0);
115 br_multicast_disable_port(p);
116
117 br_configuration_update(br);
118
119 br_port_state_selection(br);
120
121 if (br_is_root_bridge(br) && !wasroot)
122 br_become_root_bridge(br);
123}
124
125static void br_stp_start(struct net_bridge *br)
126{
127 int r;
128 char *argv[] = { BR_STP_PROG, br->dev->name, "start", NULL };
129 char *envp[] = { NULL };
130
131 r = call_usermodehelper(BR_STP_PROG, argv, envp, UMH_WAIT_PROC);
132
133 spin_lock_bh(&br->lock);
134
135 if (br->bridge_forward_delay < BR_MIN_FORWARD_DELAY)
136 __br_set_forward_delay(br, BR_MIN_FORWARD_DELAY);
137 else if (br->bridge_forward_delay > BR_MAX_FORWARD_DELAY)
138 __br_set_forward_delay(br, BR_MAX_FORWARD_DELAY);
139
140 if (r == 0) {
141 br->stp_enabled = BR_USER_STP;
142 br_debug(br, "userspace STP started\n");
143 } else {
144 br->stp_enabled = BR_KERNEL_STP;
145 br_debug(br, "using kernel STP\n");
146
147 /* To start timers on any ports left in blocking */
148 br_port_state_selection(br);
149 }
150
151 spin_unlock_bh(&br->lock);
152}
153
154static void br_stp_stop(struct net_bridge *br)
155{
156 int r;
157 char *argv[] = { BR_STP_PROG, br->dev->name, "stop", NULL };
158 char *envp[] = { NULL };
159
160 if (br->stp_enabled == BR_USER_STP) {
161 r = call_usermodehelper(BR_STP_PROG, argv, envp, UMH_WAIT_PROC);
162 br_info(br, "userspace STP stopped, return code %d\n", r);
163
164 /* To start timers on any ports left in blocking */
165 spin_lock_bh(&br->lock);
166 br_port_state_selection(br);
167 spin_unlock_bh(&br->lock);
168 }
169
170 br->stp_enabled = BR_NO_STP;
171}
172
173void br_stp_set_enabled(struct net_bridge *br, unsigned long val)
174{
175 ASSERT_RTNL();
176
177 if (val) {
178 if (br->stp_enabled == BR_NO_STP)
179 br_stp_start(br);
180 } else {
181 if (br->stp_enabled != BR_NO_STP)
182 br_stp_stop(br);
183 }
184}
185
186/* called under bridge lock */
187void br_stp_change_bridge_id(struct net_bridge *br, const unsigned char *addr)
188{
189 /* should be aligned on 2 bytes for ether_addr_equal() */
190 unsigned short oldaddr_aligned[ETH_ALEN >> 1];
191 unsigned char *oldaddr = (unsigned char *)oldaddr_aligned;
192 struct net_bridge_port *p;
193 int wasroot;
194
195 wasroot = br_is_root_bridge(br);
196
197 br_fdb_change_mac_address(br, addr);
198
199 memcpy(oldaddr, br->bridge_id.addr, ETH_ALEN);
200 memcpy(br->bridge_id.addr, addr, ETH_ALEN);
201 memcpy(br->dev->dev_addr, addr, ETH_ALEN);
202
203 list_for_each_entry(p, &br->port_list, list) {
204 if (ether_addr_equal(p->designated_bridge.addr, oldaddr))
205 memcpy(p->designated_bridge.addr, addr, ETH_ALEN);
206
207 if (ether_addr_equal(p->designated_root.addr, oldaddr))
208 memcpy(p->designated_root.addr, addr, ETH_ALEN);
209 }
210
211 br_configuration_update(br);
212 br_port_state_selection(br);
213 if (br_is_root_bridge(br) && !wasroot)
214 br_become_root_bridge(br);
215}
216
217/* should be aligned on 2 bytes for ether_addr_equal() */
218static const unsigned short br_mac_zero_aligned[ETH_ALEN >> 1];
219
220/* called under bridge lock */
221bool br_stp_recalculate_bridge_id(struct net_bridge *br)
222{
223 const unsigned char *br_mac_zero =
224 (const unsigned char *)br_mac_zero_aligned;
225 const unsigned char *addr = br_mac_zero;
226 struct net_bridge_port *p;
227
228 /* user has chosen a value so keep it */
229 if (br->dev->addr_assign_type == NET_ADDR_SET)
230 return false;
231
232 list_for_each_entry(p, &br->port_list, list) {
233 if (addr == br_mac_zero ||
234 memcmp(p->dev->dev_addr, addr, ETH_ALEN) < 0)
235 addr = p->dev->dev_addr;
236
237 }
238
239 if (ether_addr_equal(br->bridge_id.addr, addr))
240 return false; /* no change */
241
242 br_stp_change_bridge_id(br, addr);
243 return true;
244}
245
246/* called under bridge lock */
247void br_stp_set_bridge_priority(struct net_bridge *br, u16 newprio)
248{
249 struct net_bridge_port *p;
250 int wasroot;
251
252 wasroot = br_is_root_bridge(br);
253
254 list_for_each_entry(p, &br->port_list, list) {
255 if (p->state != BR_STATE_DISABLED &&
256 br_is_designated_port(p)) {
257 p->designated_bridge.prio[0] = (newprio >> 8) & 0xFF;
258 p->designated_bridge.prio[1] = newprio & 0xFF;
259 }
260
261 }
262
263 br->bridge_id.prio[0] = (newprio >> 8) & 0xFF;
264 br->bridge_id.prio[1] = newprio & 0xFF;
265 br_configuration_update(br);
266 br_port_state_selection(br);
267 if (br_is_root_bridge(br) && !wasroot)
268 br_become_root_bridge(br);
269}
270
271/* called under bridge lock */
272int br_stp_set_port_priority(struct net_bridge_port *p, unsigned long newprio)
273{
274 port_id new_port_id;
275
276 if (newprio > BR_MAX_PORT_PRIORITY)
277 return -ERANGE;
278
279 new_port_id = br_make_port_id(newprio, p->port_no);
280 if (br_is_designated_port(p))
281 p->designated_port = new_port_id;
282
283 p->port_id = new_port_id;
284 p->priority = newprio;
285 if (!memcmp(&p->br->bridge_id, &p->designated_bridge, 8) &&
286 p->port_id < p->designated_port) {
287 br_become_designated_port(p);
288 br_port_state_selection(p->br);
289 }
290
291 return 0;
292}
293
294/* called under bridge lock */
295int br_stp_set_path_cost(struct net_bridge_port *p, unsigned long path_cost)
296{
297 if (path_cost < BR_MIN_PATH_COST ||
298 path_cost > BR_MAX_PATH_COST)
299 return -ERANGE;
300
301 p->flags |= BR_ADMIN_COST;
302 p->path_cost = path_cost;
303 br_configuration_update(p->br);
304 br_port_state_selection(p->br);
305 return 0;
306}
307
308ssize_t br_show_bridge_id(char *buf, const struct bridge_id *id)
309{
310 return sprintf(buf, "%.2x%.2x.%.2x%.2x%.2x%.2x%.2x%.2x\n",
311 id->prio[0], id->prio[1],
312 id->addr[0], id->addr[1], id->addr[2],
313 id->addr[3], id->addr[4], id->addr[5]);
314}