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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 struct switchdev_attr attr = {
40 .orig_dev = p->dev,
41 .id = SWITCHDEV_ATTR_ID_BRIDGE_AGEING_TIME,
42 .flags = SWITCHDEV_F_SKIP_EOPNOTSUPP | SWITCHDEV_F_DEFER,
43 .u.ageing_time = jiffies_to_clock_t(p->br->ageing_time),
44 };
45 int err;
46
47 p->port_id = br_make_port_id(p->priority, p->port_no);
48 br_become_designated_port(p);
49 br_set_state(p, BR_STATE_BLOCKING);
50 p->topology_change_ack = 0;
51 p->config_pending = 0;
52
53 err = switchdev_port_attr_set(p->dev, &attr);
54 if (err && err != -EOPNOTSUPP)
55 netdev_err(p->dev, "failed to set HW ageing time\n");
56}
57
58/* called under bridge lock */
59void br_stp_enable_bridge(struct net_bridge *br)
60{
61 struct net_bridge_port *p;
62
63 spin_lock_bh(&br->lock);
64 if (br->stp_enabled == BR_KERNEL_STP)
65 mod_timer(&br->hello_timer, jiffies + br->hello_time);
66 mod_timer(&br->gc_timer, jiffies + HZ/10);
67
68 br_config_bpdu_generation(br);
69
70 list_for_each_entry(p, &br->port_list, list) {
71 if (netif_running(p->dev) && netif_oper_up(p->dev))
72 br_stp_enable_port(p);
73
74 }
75 spin_unlock_bh(&br->lock);
76}
77
78/* NO locks held */
79void br_stp_disable_bridge(struct net_bridge *br)
80{
81 struct net_bridge_port *p;
82
83 spin_lock_bh(&br->lock);
84 list_for_each_entry(p, &br->port_list, list) {
85 if (p->state != BR_STATE_DISABLED)
86 br_stp_disable_port(p);
87
88 }
89
90 br->topology_change = 0;
91 br->topology_change_detected = 0;
92 spin_unlock_bh(&br->lock);
93
94 del_timer_sync(&br->hello_timer);
95 del_timer_sync(&br->topology_change_timer);
96 del_timer_sync(&br->tcn_timer);
97 del_timer_sync(&br->gc_timer);
98}
99
100/* called under bridge lock */
101void br_stp_enable_port(struct net_bridge_port *p)
102{
103 br_init_port(p);
104 br_port_state_selection(p->br);
105 br_ifinfo_notify(RTM_NEWLINK, p);
106}
107
108/* called under bridge lock */
109void br_stp_disable_port(struct net_bridge_port *p)
110{
111 struct net_bridge *br = p->br;
112 int wasroot;
113
114 wasroot = br_is_root_bridge(br);
115 br_become_designated_port(p);
116 br_set_state(p, BR_STATE_DISABLED);
117 p->topology_change_ack = 0;
118 p->config_pending = 0;
119
120 br_ifinfo_notify(RTM_NEWLINK, p);
121
122 del_timer(&p->message_age_timer);
123 del_timer(&p->forward_delay_timer);
124 del_timer(&p->hold_timer);
125
126 br_fdb_delete_by_port(br, p, 0, 0);
127 br_multicast_disable_port(p);
128
129 br_configuration_update(br);
130
131 br_port_state_selection(br);
132
133 if (br_is_root_bridge(br) && !wasroot)
134 br_become_root_bridge(br);
135}
136
137static void br_stp_start(struct net_bridge *br)
138{
139 int r;
140 char *argv[] = { BR_STP_PROG, br->dev->name, "start", NULL };
141 char *envp[] = { NULL };
142 struct net_bridge_port *p;
143
144 if (net_eq(dev_net(br->dev), &init_net))
145 r = call_usermodehelper(BR_STP_PROG, argv, envp, UMH_WAIT_PROC);
146 else
147 r = -ENOENT;
148
149 spin_lock_bh(&br->lock);
150
151 if (br->bridge_forward_delay < BR_MIN_FORWARD_DELAY)
152 __br_set_forward_delay(br, BR_MIN_FORWARD_DELAY);
153 else if (br->bridge_forward_delay > BR_MAX_FORWARD_DELAY)
154 __br_set_forward_delay(br, BR_MAX_FORWARD_DELAY);
155
156 if (r == 0) {
157 br->stp_enabled = BR_USER_STP;
158 br_debug(br, "userspace STP started\n");
159 /* Stop hello and hold timers */
160 del_timer(&br->hello_timer);
161 list_for_each_entry(p, &br->port_list, list)
162 del_timer(&p->hold_timer);
163 } else {
164 br->stp_enabled = BR_KERNEL_STP;
165 br_debug(br, "using kernel STP\n");
166
167 /* To start timers on any ports left in blocking */
168 br_port_state_selection(br);
169 }
170
171 spin_unlock_bh(&br->lock);
172}
173
174static void br_stp_stop(struct net_bridge *br)
175{
176 int r;
177 char *argv[] = { BR_STP_PROG, br->dev->name, "stop", NULL };
178 char *envp[] = { NULL };
179 struct net_bridge_port *p;
180
181 if (br->stp_enabled == BR_USER_STP) {
182 r = call_usermodehelper(BR_STP_PROG, argv, envp, UMH_WAIT_PROC);
183 br_info(br, "userspace STP stopped, return code %d\n", r);
184
185 /* To start timers on any ports left in blocking */
186 mod_timer(&br->hello_timer, jiffies + br->hello_time);
187 list_for_each_entry(p, &br->port_list, list)
188 mod_timer(&p->hold_timer,
189 round_jiffies(jiffies + BR_HOLD_TIME));
190 spin_lock_bh(&br->lock);
191 br_port_state_selection(br);
192 spin_unlock_bh(&br->lock);
193 }
194
195 br->stp_enabled = BR_NO_STP;
196}
197
198void br_stp_set_enabled(struct net_bridge *br, unsigned long val)
199{
200 ASSERT_RTNL();
201
202 if (val) {
203 if (br->stp_enabled == BR_NO_STP)
204 br_stp_start(br);
205 } else {
206 if (br->stp_enabled != BR_NO_STP)
207 br_stp_stop(br);
208 }
209}
210
211/* called under bridge lock */
212void br_stp_change_bridge_id(struct net_bridge *br, const unsigned char *addr)
213{
214 /* should be aligned on 2 bytes for ether_addr_equal() */
215 unsigned short oldaddr_aligned[ETH_ALEN >> 1];
216 unsigned char *oldaddr = (unsigned char *)oldaddr_aligned;
217 struct net_bridge_port *p;
218 int wasroot;
219
220 wasroot = br_is_root_bridge(br);
221
222 br_fdb_change_mac_address(br, addr);
223
224 memcpy(oldaddr, br->bridge_id.addr, ETH_ALEN);
225 memcpy(br->bridge_id.addr, addr, ETH_ALEN);
226 memcpy(br->dev->dev_addr, addr, ETH_ALEN);
227
228 list_for_each_entry(p, &br->port_list, list) {
229 if (ether_addr_equal(p->designated_bridge.addr, oldaddr))
230 memcpy(p->designated_bridge.addr, addr, ETH_ALEN);
231
232 if (ether_addr_equal(p->designated_root.addr, oldaddr))
233 memcpy(p->designated_root.addr, addr, ETH_ALEN);
234 }
235
236 br_configuration_update(br);
237 br_port_state_selection(br);
238 if (br_is_root_bridge(br) && !wasroot)
239 br_become_root_bridge(br);
240}
241
242/* should be aligned on 2 bytes for ether_addr_equal() */
243static const unsigned short br_mac_zero_aligned[ETH_ALEN >> 1];
244
245/* called under bridge lock */
246bool br_stp_recalculate_bridge_id(struct net_bridge *br)
247{
248 const unsigned char *br_mac_zero =
249 (const unsigned char *)br_mac_zero_aligned;
250 const unsigned char *addr = br_mac_zero;
251 struct net_bridge_port *p;
252
253 /* user has chosen a value so keep it */
254 if (br->dev->addr_assign_type == NET_ADDR_SET)
255 return false;
256
257 list_for_each_entry(p, &br->port_list, list) {
258 if (addr == br_mac_zero ||
259 memcmp(p->dev->dev_addr, addr, ETH_ALEN) < 0)
260 addr = p->dev->dev_addr;
261
262 }
263
264 if (ether_addr_equal(br->bridge_id.addr, addr))
265 return false; /* no change */
266
267 br_stp_change_bridge_id(br, addr);
268 return true;
269}
270
271/* Acquires and releases bridge lock */
272void br_stp_set_bridge_priority(struct net_bridge *br, u16 newprio)
273{
274 struct net_bridge_port *p;
275 int wasroot;
276
277 spin_lock_bh(&br->lock);
278 wasroot = br_is_root_bridge(br);
279
280 list_for_each_entry(p, &br->port_list, list) {
281 if (p->state != BR_STATE_DISABLED &&
282 br_is_designated_port(p)) {
283 p->designated_bridge.prio[0] = (newprio >> 8) & 0xFF;
284 p->designated_bridge.prio[1] = newprio & 0xFF;
285 }
286
287 }
288
289 br->bridge_id.prio[0] = (newprio >> 8) & 0xFF;
290 br->bridge_id.prio[1] = newprio & 0xFF;
291 br_configuration_update(br);
292 br_port_state_selection(br);
293 if (br_is_root_bridge(br) && !wasroot)
294 br_become_root_bridge(br);
295 spin_unlock_bh(&br->lock);
296}
297
298/* called under bridge lock */
299int br_stp_set_port_priority(struct net_bridge_port *p, unsigned long newprio)
300{
301 port_id new_port_id;
302
303 if (newprio > BR_MAX_PORT_PRIORITY)
304 return -ERANGE;
305
306 new_port_id = br_make_port_id(newprio, p->port_no);
307 if (br_is_designated_port(p))
308 p->designated_port = new_port_id;
309
310 p->port_id = new_port_id;
311 p->priority = newprio;
312 if (!memcmp(&p->br->bridge_id, &p->designated_bridge, 8) &&
313 p->port_id < p->designated_port) {
314 br_become_designated_port(p);
315 br_port_state_selection(p->br);
316 }
317
318 return 0;
319}
320
321/* called under bridge lock */
322int br_stp_set_path_cost(struct net_bridge_port *p, unsigned long path_cost)
323{
324 if (path_cost < BR_MIN_PATH_COST ||
325 path_cost > BR_MAX_PATH_COST)
326 return -ERANGE;
327
328 p->flags |= BR_ADMIN_COST;
329 p->path_cost = path_cost;
330 br_configuration_update(p->br);
331 br_port_state_selection(p->br);
332 return 0;
333}
334
335ssize_t br_show_bridge_id(char *buf, const struct bridge_id *id)
336{
337 return sprintf(buf, "%.2x%.2x.%.2x%.2x%.2x%.2x%.2x%.2x\n",
338 id->prio[0], id->prio[1],
339 id->addr[0], id->addr[1], id->addr[2],
340 id->addr[3], id->addr[4], id->addr[5]);
341}
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 eth_hw_addr_set(br->dev, addr);
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}