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 */
br_make_port_id(__u8 priority,__u16 port_no)28 static 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 */
br_init_port(struct net_bridge_port * p)37 void 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 /* NO locks held */
br_stp_enable_bridge(struct net_bridge * br)59 void 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 */
br_stp_disable_bridge(struct net_bridge * br)79 void 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 */
br_stp_enable_port(struct net_bridge_port * p)101 void 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 */
br_stp_disable_port(struct net_bridge_port * p)109 void 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
br_stp_call_user(struct net_bridge * br,char * arg)137 static int br_stp_call_user(struct net_bridge *br, char *arg)
138 {
139 char *argv[] = { BR_STP_PROG, br->dev->name, arg, NULL };
140 char *envp[] = { NULL };
141 int rc;
142
143 /* call userspace STP and report program errors */
144 rc = call_usermodehelper(BR_STP_PROG, argv, envp, UMH_WAIT_PROC);
145 if (rc > 0) {
146 if (rc & 0xff)
147 br_debug(br, BR_STP_PROG " received signal %d\n",
148 rc & 0x7f);
149 else
150 br_debug(br, BR_STP_PROG " exited with code %d\n",
151 (rc >> 8) & 0xff);
152 }
153
154 return rc;
155 }
156
br_stp_start(struct net_bridge * br)157 static void br_stp_start(struct net_bridge *br)
158 {
159 struct net_bridge_port *p;
160 int err = -ENOENT;
161
162 if (net_eq(dev_net(br->dev), &init_net))
163 err = br_stp_call_user(br, "start");
164
165 if (err && err != -ENOENT)
166 br_err(br, "failed to start userspace STP (%d)\n", err);
167
168 spin_lock_bh(&br->lock);
169
170 if (br->bridge_forward_delay < BR_MIN_FORWARD_DELAY)
171 __br_set_forward_delay(br, BR_MIN_FORWARD_DELAY);
172 else if (br->bridge_forward_delay > BR_MAX_FORWARD_DELAY)
173 __br_set_forward_delay(br, BR_MAX_FORWARD_DELAY);
174
175 if (!err) {
176 br->stp_enabled = BR_USER_STP;
177 br_debug(br, "userspace STP started\n");
178
179 /* Stop hello and hold timers */
180 del_timer(&br->hello_timer);
181 list_for_each_entry(p, &br->port_list, list)
182 del_timer(&p->hold_timer);
183 } else {
184 br->stp_enabled = BR_KERNEL_STP;
185 br_debug(br, "using kernel STP\n");
186
187 /* To start timers on any ports left in blocking */
188 if (br->dev->flags & IFF_UP)
189 mod_timer(&br->hello_timer, jiffies + br->hello_time);
190 br_port_state_selection(br);
191 }
192
193 spin_unlock_bh(&br->lock);
194 }
195
br_stp_stop(struct net_bridge * br)196 static void br_stp_stop(struct net_bridge *br)
197 {
198 struct net_bridge_port *p;
199 int err;
200
201 if (br->stp_enabled == BR_USER_STP) {
202 err = br_stp_call_user(br, "stop");
203 if (err)
204 br_err(br, "failed to stop userspace STP (%d)\n", err);
205
206 /* To start timers on any ports left in blocking */
207 mod_timer(&br->hello_timer, jiffies + br->hello_time);
208 list_for_each_entry(p, &br->port_list, list)
209 mod_timer(&p->hold_timer,
210 round_jiffies(jiffies + BR_HOLD_TIME));
211 spin_lock_bh(&br->lock);
212 br_port_state_selection(br);
213 spin_unlock_bh(&br->lock);
214 }
215
216 br->stp_enabled = BR_NO_STP;
217 }
218
br_stp_set_enabled(struct net_bridge * br,unsigned long val)219 void br_stp_set_enabled(struct net_bridge *br, unsigned long val)
220 {
221 ASSERT_RTNL();
222
223 if (val) {
224 if (br->stp_enabled == BR_NO_STP)
225 br_stp_start(br);
226 } else {
227 if (br->stp_enabled != BR_NO_STP)
228 br_stp_stop(br);
229 }
230 }
231
232 /* called under bridge lock */
br_stp_change_bridge_id(struct net_bridge * br,const unsigned char * addr)233 void br_stp_change_bridge_id(struct net_bridge *br, const unsigned char *addr)
234 {
235 /* should be aligned on 2 bytes for ether_addr_equal() */
236 unsigned short oldaddr_aligned[ETH_ALEN >> 1];
237 unsigned char *oldaddr = (unsigned char *)oldaddr_aligned;
238 struct net_bridge_port *p;
239 int wasroot;
240
241 wasroot = br_is_root_bridge(br);
242
243 br_fdb_change_mac_address(br, addr);
244
245 memcpy(oldaddr, br->bridge_id.addr, ETH_ALEN);
246 memcpy(br->bridge_id.addr, addr, ETH_ALEN);
247 memcpy(br->dev->dev_addr, addr, ETH_ALEN);
248
249 list_for_each_entry(p, &br->port_list, list) {
250 if (ether_addr_equal(p->designated_bridge.addr, oldaddr))
251 memcpy(p->designated_bridge.addr, addr, ETH_ALEN);
252
253 if (ether_addr_equal(p->designated_root.addr, oldaddr))
254 memcpy(p->designated_root.addr, addr, ETH_ALEN);
255 }
256
257 br_configuration_update(br);
258 br_port_state_selection(br);
259 if (br_is_root_bridge(br) && !wasroot)
260 br_become_root_bridge(br);
261 }
262
263 /* should be aligned on 2 bytes for ether_addr_equal() */
264 static const unsigned short br_mac_zero_aligned[ETH_ALEN >> 1];
265
266 /* called under bridge lock */
br_stp_recalculate_bridge_id(struct net_bridge * br)267 bool br_stp_recalculate_bridge_id(struct net_bridge *br)
268 {
269 const unsigned char *br_mac_zero =
270 (const unsigned char *)br_mac_zero_aligned;
271 const unsigned char *addr = br_mac_zero;
272 struct net_bridge_port *p;
273
274 /* user has chosen a value so keep it */
275 if (br->dev->addr_assign_type == NET_ADDR_SET)
276 return false;
277
278 list_for_each_entry(p, &br->port_list, list) {
279 if (addr == br_mac_zero ||
280 memcmp(p->dev->dev_addr, addr, ETH_ALEN) < 0)
281 addr = p->dev->dev_addr;
282
283 }
284
285 if (ether_addr_equal(br->bridge_id.addr, addr))
286 return false; /* no change */
287
288 br_stp_change_bridge_id(br, addr);
289 return true;
290 }
291
292 /* Acquires and releases bridge lock */
br_stp_set_bridge_priority(struct net_bridge * br,u16 newprio)293 void br_stp_set_bridge_priority(struct net_bridge *br, u16 newprio)
294 {
295 struct net_bridge_port *p;
296 int wasroot;
297
298 spin_lock_bh(&br->lock);
299 wasroot = br_is_root_bridge(br);
300
301 list_for_each_entry(p, &br->port_list, list) {
302 if (p->state != BR_STATE_DISABLED &&
303 br_is_designated_port(p)) {
304 p->designated_bridge.prio[0] = (newprio >> 8) & 0xFF;
305 p->designated_bridge.prio[1] = newprio & 0xFF;
306 }
307
308 }
309
310 br->bridge_id.prio[0] = (newprio >> 8) & 0xFF;
311 br->bridge_id.prio[1] = newprio & 0xFF;
312 br_configuration_update(br);
313 br_port_state_selection(br);
314 if (br_is_root_bridge(br) && !wasroot)
315 br_become_root_bridge(br);
316 spin_unlock_bh(&br->lock);
317 }
318
319 /* called under bridge lock */
br_stp_set_port_priority(struct net_bridge_port * p,unsigned long newprio)320 int br_stp_set_port_priority(struct net_bridge_port *p, unsigned long newprio)
321 {
322 port_id new_port_id;
323
324 if (newprio > BR_MAX_PORT_PRIORITY)
325 return -ERANGE;
326
327 new_port_id = br_make_port_id(newprio, p->port_no);
328 if (br_is_designated_port(p))
329 p->designated_port = new_port_id;
330
331 p->port_id = new_port_id;
332 p->priority = newprio;
333 if (!memcmp(&p->br->bridge_id, &p->designated_bridge, 8) &&
334 p->port_id < p->designated_port) {
335 br_become_designated_port(p);
336 br_port_state_selection(p->br);
337 }
338
339 return 0;
340 }
341
342 /* called under bridge lock */
br_stp_set_path_cost(struct net_bridge_port * p,unsigned long path_cost)343 int br_stp_set_path_cost(struct net_bridge_port *p, unsigned long path_cost)
344 {
345 if (path_cost < BR_MIN_PATH_COST ||
346 path_cost > BR_MAX_PATH_COST)
347 return -ERANGE;
348
349 p->flags |= BR_ADMIN_COST;
350 p->path_cost = path_cost;
351 br_configuration_update(p->br);
352 br_port_state_selection(p->br);
353 return 0;
354 }
355
br_show_bridge_id(char * buf,const struct bridge_id * id)356 ssize_t br_show_bridge_id(char *buf, const struct bridge_id *id)
357 {
358 return sprintf(buf, "%.2x%.2x.%.2x%.2x%.2x%.2x%.2x%.2x\n",
359 id->prio[0], id->prio[1],
360 id->addr[0], id->addr[1], id->addr[2],
361 id->addr[3], id->addr[4], id->addr[5]);
362 }
363