xref: /openbmc/linux/net/bridge/br_stp_if.c (revision abfbd895)
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  */
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 */
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 */
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 */
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 */
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 */
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 
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 		br_port_state_selection(br);
170 	}
171 
172 	spin_unlock_bh(&br->lock);
173 }
174 
175 static void br_stp_stop(struct net_bridge *br)
176 {
177 	int r;
178 	char *argv[] = { BR_STP_PROG, br->dev->name, "stop", NULL };
179 	char *envp[] = { NULL };
180 	struct net_bridge_port *p;
181 
182 	if (br->stp_enabled == BR_USER_STP) {
183 		r = call_usermodehelper(BR_STP_PROG, argv, envp, UMH_WAIT_PROC);
184 		br_info(br, "userspace STP stopped, return code %d\n", r);
185 
186 		/* To start timers on any ports left in blocking */
187 		mod_timer(&br->hello_timer, jiffies + br->hello_time);
188 		list_for_each_entry(p, &br->port_list, list)
189 			mod_timer(&p->hold_timer,
190 				  round_jiffies(jiffies + BR_HOLD_TIME));
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 
199 void 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 */
213 void 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() */
244 static const unsigned short br_mac_zero_aligned[ETH_ALEN >> 1];
245 
246 /* called under bridge lock */
247 bool 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 */
273 void 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 */
300 int 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 */
323 int 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 
336 ssize_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 }
343