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 .id = SWITCHDEV_ATTR_ID_BRIDGE_AGEING_TIME,
41 .flags = SWITCHDEV_F_SKIP_EOPNOTSUPP | SWITCHDEV_F_DEFER,
42 .u.ageing_time = jiffies_to_clock_t(p->br->ageing_time),
43 };
44 int err;
45
46 p->port_id = br_make_port_id(p->priority, p->port_no);
47 br_become_designated_port(p);
48 br_set_state(p, BR_STATE_BLOCKING);
49 p->topology_change_ack = 0;
50 p->config_pending = 0;
51
52 err = switchdev_port_attr_set(p->dev, &attr);
53 if (err && err != -EOPNOTSUPP)
54 netdev_err(p->dev, "failed to set HW ageing time\n");
55 }
56
57 /* called under bridge lock */
br_stp_enable_bridge(struct net_bridge * br)58 void br_stp_enable_bridge(struct net_bridge *br)
59 {
60 struct net_bridge_port *p;
61
62 spin_lock_bh(&br->lock);
63 if (br->stp_enabled == BR_KERNEL_STP)
64 mod_timer(&br->hello_timer, jiffies + br->hello_time);
65 mod_timer(&br->gc_timer, jiffies + HZ/10);
66
67 br_config_bpdu_generation(br);
68
69 list_for_each_entry(p, &br->port_list, list) {
70 if (netif_running(p->dev) && netif_oper_up(p->dev))
71 br_stp_enable_port(p);
72
73 }
74 spin_unlock_bh(&br->lock);
75 }
76
77 /* NO locks held */
br_stp_disable_bridge(struct net_bridge * br)78 void br_stp_disable_bridge(struct net_bridge *br)
79 {
80 struct net_bridge_port *p;
81
82 spin_lock_bh(&br->lock);
83 list_for_each_entry(p, &br->port_list, list) {
84 if (p->state != BR_STATE_DISABLED)
85 br_stp_disable_port(p);
86
87 }
88
89 br->topology_change = 0;
90 br->topology_change_detected = 0;
91 spin_unlock_bh(&br->lock);
92
93 del_timer_sync(&br->hello_timer);
94 del_timer_sync(&br->topology_change_timer);
95 del_timer_sync(&br->tcn_timer);
96 del_timer_sync(&br->gc_timer);
97 }
98
99 /* called under bridge lock */
br_stp_enable_port(struct net_bridge_port * p)100 void br_stp_enable_port(struct net_bridge_port *p)
101 {
102 br_init_port(p);
103 br_port_state_selection(p->br);
104 br_log_state(p);
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_log_state(p);
121 br_ifinfo_notify(RTM_NEWLINK, p);
122
123 del_timer(&p->message_age_timer);
124 del_timer(&p->forward_delay_timer);
125 del_timer(&p->hold_timer);
126
127 br_fdb_delete_by_port(br, p, 0, 0);
128 br_multicast_disable_port(p);
129
130 br_configuration_update(br);
131
132 br_port_state_selection(br);
133
134 if (br_is_root_bridge(br) && !wasroot)
135 br_become_root_bridge(br);
136 }
137
br_stp_start(struct net_bridge * br)138 static void br_stp_start(struct net_bridge *br)
139 {
140 int r;
141 char *argv[] = { BR_STP_PROG, br->dev->name, "start", NULL };
142 char *envp[] = { NULL };
143 struct net_bridge_port *p;
144
145 if (net_eq(dev_net(br->dev), &init_net))
146 r = call_usermodehelper(BR_STP_PROG, argv, envp, UMH_WAIT_PROC);
147 else
148 r = -ENOENT;
149
150 spin_lock_bh(&br->lock);
151
152 if (br->bridge_forward_delay < BR_MIN_FORWARD_DELAY)
153 __br_set_forward_delay(br, BR_MIN_FORWARD_DELAY);
154 else if (br->bridge_forward_delay > BR_MAX_FORWARD_DELAY)
155 __br_set_forward_delay(br, BR_MAX_FORWARD_DELAY);
156
157 if (r == 0) {
158 br->stp_enabled = BR_USER_STP;
159 br_debug(br, "userspace STP started\n");
160 /* Stop hello and hold timers */
161 del_timer(&br->hello_timer);
162 list_for_each_entry(p, &br->port_list, list)
163 del_timer(&p->hold_timer);
164 } else {
165 br->stp_enabled = BR_KERNEL_STP;
166 br_debug(br, "using kernel STP\n");
167
168 /* To start timers on any ports left in blocking */
169 if (br->dev->flags & IFF_UP)
170 mod_timer(&br->hello_timer, jiffies + br->hello_time);
171 br_port_state_selection(br);
172 }
173
174 spin_unlock_bh(&br->lock);
175 }
176
br_stp_stop(struct net_bridge * br)177 static void br_stp_stop(struct net_bridge *br)
178 {
179 int r;
180 char *argv[] = { BR_STP_PROG, br->dev->name, "stop", NULL };
181 char *envp[] = { NULL };
182 struct net_bridge_port *p;
183
184 if (br->stp_enabled == BR_USER_STP) {
185 r = call_usermodehelper(BR_STP_PROG, argv, envp, UMH_WAIT_PROC);
186 br_info(br, "userspace STP stopped, return code %d\n", r);
187
188 /* To start timers on any ports left in blocking */
189 mod_timer(&br->hello_timer, jiffies + br->hello_time);
190 list_for_each_entry(p, &br->port_list, list)
191 mod_timer(&p->hold_timer,
192 round_jiffies(jiffies + BR_HOLD_TIME));
193 spin_lock_bh(&br->lock);
194 br_port_state_selection(br);
195 spin_unlock_bh(&br->lock);
196 }
197
198 br->stp_enabled = BR_NO_STP;
199 }
200
br_stp_set_enabled(struct net_bridge * br,unsigned long val)201 void br_stp_set_enabled(struct net_bridge *br, unsigned long val)
202 {
203 ASSERT_RTNL();
204
205 if (val) {
206 if (br->stp_enabled == BR_NO_STP)
207 br_stp_start(br);
208 } else {
209 if (br->stp_enabled != BR_NO_STP)
210 br_stp_stop(br);
211 }
212 }
213
214 /* called under bridge lock */
br_stp_change_bridge_id(struct net_bridge * br,const unsigned char * addr)215 void br_stp_change_bridge_id(struct net_bridge *br, const unsigned char *addr)
216 {
217 /* should be aligned on 2 bytes for ether_addr_equal() */
218 unsigned short oldaddr_aligned[ETH_ALEN >> 1];
219 unsigned char *oldaddr = (unsigned char *)oldaddr_aligned;
220 struct net_bridge_port *p;
221 int wasroot;
222
223 wasroot = br_is_root_bridge(br);
224
225 br_fdb_change_mac_address(br, addr);
226
227 memcpy(oldaddr, br->bridge_id.addr, ETH_ALEN);
228 memcpy(br->bridge_id.addr, addr, ETH_ALEN);
229 memcpy(br->dev->dev_addr, addr, ETH_ALEN);
230
231 list_for_each_entry(p, &br->port_list, list) {
232 if (ether_addr_equal(p->designated_bridge.addr, oldaddr))
233 memcpy(p->designated_bridge.addr, addr, ETH_ALEN);
234
235 if (ether_addr_equal(p->designated_root.addr, oldaddr))
236 memcpy(p->designated_root.addr, addr, ETH_ALEN);
237 }
238
239 br_configuration_update(br);
240 br_port_state_selection(br);
241 if (br_is_root_bridge(br) && !wasroot)
242 br_become_root_bridge(br);
243 }
244
245 /* should be aligned on 2 bytes for ether_addr_equal() */
246 static const unsigned short br_mac_zero_aligned[ETH_ALEN >> 1];
247
248 /* called under bridge lock */
br_stp_recalculate_bridge_id(struct net_bridge * br)249 bool br_stp_recalculate_bridge_id(struct net_bridge *br)
250 {
251 const unsigned char *br_mac_zero =
252 (const unsigned char *)br_mac_zero_aligned;
253 const unsigned char *addr = br_mac_zero;
254 struct net_bridge_port *p;
255
256 /* user has chosen a value so keep it */
257 if (br->dev->addr_assign_type == NET_ADDR_SET)
258 return false;
259
260 list_for_each_entry(p, &br->port_list, list) {
261 if (addr == br_mac_zero ||
262 memcmp(p->dev->dev_addr, addr, ETH_ALEN) < 0)
263 addr = p->dev->dev_addr;
264
265 }
266
267 if (ether_addr_equal(br->bridge_id.addr, addr))
268 return false; /* no change */
269
270 br_stp_change_bridge_id(br, addr);
271 return true;
272 }
273
274 /* Acquires and releases bridge lock */
br_stp_set_bridge_priority(struct net_bridge * br,u16 newprio)275 void br_stp_set_bridge_priority(struct net_bridge *br, u16 newprio)
276 {
277 struct net_bridge_port *p;
278 int wasroot;
279
280 spin_lock_bh(&br->lock);
281 wasroot = br_is_root_bridge(br);
282
283 list_for_each_entry(p, &br->port_list, list) {
284 if (p->state != BR_STATE_DISABLED &&
285 br_is_designated_port(p)) {
286 p->designated_bridge.prio[0] = (newprio >> 8) & 0xFF;
287 p->designated_bridge.prio[1] = newprio & 0xFF;
288 }
289
290 }
291
292 br->bridge_id.prio[0] = (newprio >> 8) & 0xFF;
293 br->bridge_id.prio[1] = newprio & 0xFF;
294 br_configuration_update(br);
295 br_port_state_selection(br);
296 if (br_is_root_bridge(br) && !wasroot)
297 br_become_root_bridge(br);
298 spin_unlock_bh(&br->lock);
299 }
300
301 /* called under bridge lock */
br_stp_set_port_priority(struct net_bridge_port * p,unsigned long newprio)302 int br_stp_set_port_priority(struct net_bridge_port *p, unsigned long newprio)
303 {
304 port_id new_port_id;
305
306 if (newprio > BR_MAX_PORT_PRIORITY)
307 return -ERANGE;
308
309 new_port_id = br_make_port_id(newprio, p->port_no);
310 if (br_is_designated_port(p))
311 p->designated_port = new_port_id;
312
313 p->port_id = new_port_id;
314 p->priority = newprio;
315 if (!memcmp(&p->br->bridge_id, &p->designated_bridge, 8) &&
316 p->port_id < p->designated_port) {
317 br_become_designated_port(p);
318 br_port_state_selection(p->br);
319 }
320
321 return 0;
322 }
323
324 /* called under bridge lock */
br_stp_set_path_cost(struct net_bridge_port * p,unsigned long path_cost)325 int br_stp_set_path_cost(struct net_bridge_port *p, unsigned long path_cost)
326 {
327 if (path_cost < BR_MIN_PATH_COST ||
328 path_cost > BR_MAX_PATH_COST)
329 return -ERANGE;
330
331 p->flags |= BR_ADMIN_COST;
332 p->path_cost = path_cost;
333 br_configuration_update(p->br);
334 br_port_state_selection(p->br);
335 return 0;
336 }
337
br_show_bridge_id(char * buf,const struct bridge_id * id)338 ssize_t br_show_bridge_id(char *buf, const struct bridge_id *id)
339 {
340 return sprintf(buf, "%.2x%.2x.%.2x%.2x%.2x%.2x%.2x%.2x\n",
341 id->prio[0], id->prio[1],
342 id->addr[0], id->addr[1], id->addr[2],
343 id->addr[3], id->addr[4], id->addr[5]);
344 }
345