2 * Spanning tree protocol; interface code
3 * Linux ethernet bridge
6 * Lennert Buytenhek <buytenh@gnu.org>
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.
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>
20 #include "br_private.h"
21 #include "br_private_stp.h"
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.
28 static inline port_id br_make_port_id(__u8 priority, __u16 port_no)
30 return ((u16)priority << BR_PORT_BITS)
31 | (port_no & ((1<<BR_PORT_BITS)-1));
34 #define BR_MAX_PORT_PRIORITY ((u16)~0 >> BR_PORT_BITS)
36 /* called under bridge lock */
37 void br_init_port(struct net_bridge_port *p)
41 p->port_id = br_make_port_id(p->priority, p->port_no);
42 br_become_designated_port(p);
43 br_set_state(p, BR_STATE_BLOCKING);
44 p->topology_change_ack = 0;
45 p->config_pending = 0;
47 err = __set_ageing_time(p->dev, p->br->ageing_time);
49 netdev_err(p->dev, "failed to offload ageing time\n");
53 void br_stp_enable_bridge(struct net_bridge *br)
55 struct net_bridge_port *p;
57 spin_lock_bh(&br->lock);
58 if (br->stp_enabled == BR_KERNEL_STP)
59 mod_timer(&br->hello_timer, jiffies + br->hello_time);
60 mod_delayed_work(system_long_wq, &br->gc_work, HZ / 10);
62 br_config_bpdu_generation(br);
64 list_for_each_entry(p, &br->port_list, list) {
65 if (netif_running(p->dev) && netif_oper_up(p->dev))
66 br_stp_enable_port(p);
69 spin_unlock_bh(&br->lock);
73 void br_stp_disable_bridge(struct net_bridge *br)
75 struct net_bridge_port *p;
77 spin_lock_bh(&br->lock);
78 list_for_each_entry(p, &br->port_list, list) {
79 if (p->state != BR_STATE_DISABLED)
80 br_stp_disable_port(p);
84 __br_set_topology_change(br, 0);
85 br->topology_change_detected = 0;
86 spin_unlock_bh(&br->lock);
88 del_timer_sync(&br->hello_timer);
89 del_timer_sync(&br->topology_change_timer);
90 del_timer_sync(&br->tcn_timer);
91 cancel_delayed_work_sync(&br->gc_work);
94 /* called under bridge lock */
95 void br_stp_enable_port(struct net_bridge_port *p)
98 br_port_state_selection(p->br);
99 br_ifinfo_notify(RTM_NEWLINK, p);
102 /* called under bridge lock */
103 void br_stp_disable_port(struct net_bridge_port *p)
105 struct net_bridge *br = p->br;
108 wasroot = br_is_root_bridge(br);
109 br_become_designated_port(p);
110 br_set_state(p, BR_STATE_DISABLED);
111 p->topology_change_ack = 0;
112 p->config_pending = 0;
114 br_ifinfo_notify(RTM_NEWLINK, p);
116 del_timer(&p->message_age_timer);
117 del_timer(&p->forward_delay_timer);
118 del_timer(&p->hold_timer);
120 br_fdb_delete_by_port(br, p, 0, 0);
121 br_multicast_disable_port(p);
123 br_configuration_update(br);
125 br_port_state_selection(br);
127 if (br_is_root_bridge(br) && !wasroot)
128 br_become_root_bridge(br);
131 static int br_stp_call_user(struct net_bridge *br, char *arg)
133 char *argv[] = { BR_STP_PROG, br->dev->name, arg, NULL };
134 char *envp[] = { NULL };
137 /* call userspace STP and report program errors */
138 rc = call_usermodehelper(BR_STP_PROG, argv, envp, UMH_WAIT_PROC);
141 br_debug(br, BR_STP_PROG " received signal %d\n",
144 br_debug(br, BR_STP_PROG " exited with code %d\n",
151 static void br_stp_start(struct net_bridge *br)
153 struct net_bridge_port *p;
156 if (net_eq(dev_net(br->dev), &init_net))
157 err = br_stp_call_user(br, "start");
159 if (err && err != -ENOENT)
160 br_err(br, "failed to start userspace STP (%d)\n", err);
162 spin_lock_bh(&br->lock);
164 if (br->bridge_forward_delay < BR_MIN_FORWARD_DELAY)
165 __br_set_forward_delay(br, BR_MIN_FORWARD_DELAY);
166 else if (br->bridge_forward_delay > BR_MAX_FORWARD_DELAY)
167 __br_set_forward_delay(br, BR_MAX_FORWARD_DELAY);
170 br->stp_enabled = BR_USER_STP;
171 br_debug(br, "userspace STP started\n");
173 /* Stop hello and hold timers */
174 del_timer(&br->hello_timer);
175 list_for_each_entry(p, &br->port_list, list)
176 del_timer(&p->hold_timer);
178 br->stp_enabled = BR_KERNEL_STP;
179 br_debug(br, "using kernel STP\n");
181 /* To start timers on any ports left in blocking */
182 mod_timer(&br->hello_timer, jiffies + br->hello_time);
183 br_port_state_selection(br);
186 spin_unlock_bh(&br->lock);
189 static void br_stp_stop(struct net_bridge *br)
191 struct net_bridge_port *p;
194 if (br->stp_enabled == BR_USER_STP) {
195 err = br_stp_call_user(br, "stop");
197 br_err(br, "failed to stop userspace STP (%d)\n", err);
199 /* To start timers on any ports left in blocking */
200 mod_timer(&br->hello_timer, jiffies + br->hello_time);
201 list_for_each_entry(p, &br->port_list, list)
202 mod_timer(&p->hold_timer,
203 round_jiffies(jiffies + BR_HOLD_TIME));
204 spin_lock_bh(&br->lock);
205 br_port_state_selection(br);
206 spin_unlock_bh(&br->lock);
209 br->stp_enabled = BR_NO_STP;
212 void br_stp_set_enabled(struct net_bridge *br, unsigned long val)
217 if (br->stp_enabled == BR_NO_STP)
220 if (br->stp_enabled != BR_NO_STP)
225 /* called under bridge lock */
226 void br_stp_change_bridge_id(struct net_bridge *br, const unsigned char *addr)
228 /* should be aligned on 2 bytes for ether_addr_equal() */
229 unsigned short oldaddr_aligned[ETH_ALEN >> 1];
230 unsigned char *oldaddr = (unsigned char *)oldaddr_aligned;
231 struct net_bridge_port *p;
234 wasroot = br_is_root_bridge(br);
236 br_fdb_change_mac_address(br, addr);
238 memcpy(oldaddr, br->bridge_id.addr, ETH_ALEN);
239 memcpy(br->bridge_id.addr, addr, ETH_ALEN);
240 memcpy(br->dev->dev_addr, addr, ETH_ALEN);
242 list_for_each_entry(p, &br->port_list, list) {
243 if (ether_addr_equal(p->designated_bridge.addr, oldaddr))
244 memcpy(p->designated_bridge.addr, addr, ETH_ALEN);
246 if (ether_addr_equal(p->designated_root.addr, oldaddr))
247 memcpy(p->designated_root.addr, addr, ETH_ALEN);
250 br_configuration_update(br);
251 br_port_state_selection(br);
252 if (br_is_root_bridge(br) && !wasroot)
253 br_become_root_bridge(br);
256 /* should be aligned on 2 bytes for ether_addr_equal() */
257 static const unsigned short br_mac_zero_aligned[ETH_ALEN >> 1];
259 /* called under bridge lock */
260 bool br_stp_recalculate_bridge_id(struct net_bridge *br)
262 const unsigned char *br_mac_zero =
263 (const unsigned char *)br_mac_zero_aligned;
264 const unsigned char *addr = br_mac_zero;
265 struct net_bridge_port *p;
267 /* user has chosen a value so keep it */
268 if (br->dev->addr_assign_type == NET_ADDR_SET)
271 list_for_each_entry(p, &br->port_list, list) {
272 if (addr == br_mac_zero ||
273 memcmp(p->dev->dev_addr, addr, ETH_ALEN) < 0)
274 addr = p->dev->dev_addr;
278 if (ether_addr_equal(br->bridge_id.addr, addr))
279 return false; /* no change */
281 br_stp_change_bridge_id(br, addr);
285 /* Acquires and releases bridge lock */
286 void br_stp_set_bridge_priority(struct net_bridge *br, u16 newprio)
288 struct net_bridge_port *p;
291 spin_lock_bh(&br->lock);
292 wasroot = br_is_root_bridge(br);
294 list_for_each_entry(p, &br->port_list, list) {
295 if (p->state != BR_STATE_DISABLED &&
296 br_is_designated_port(p)) {
297 p->designated_bridge.prio[0] = (newprio >> 8) & 0xFF;
298 p->designated_bridge.prio[1] = newprio & 0xFF;
303 br->bridge_id.prio[0] = (newprio >> 8) & 0xFF;
304 br->bridge_id.prio[1] = newprio & 0xFF;
305 br_configuration_update(br);
306 br_port_state_selection(br);
307 if (br_is_root_bridge(br) && !wasroot)
308 br_become_root_bridge(br);
309 spin_unlock_bh(&br->lock);
312 /* called under bridge lock */
313 int br_stp_set_port_priority(struct net_bridge_port *p, unsigned long newprio)
317 if (newprio > BR_MAX_PORT_PRIORITY)
320 new_port_id = br_make_port_id(newprio, p->port_no);
321 if (br_is_designated_port(p))
322 p->designated_port = new_port_id;
324 p->port_id = new_port_id;
325 p->priority = newprio;
326 if (!memcmp(&p->br->bridge_id, &p->designated_bridge, 8) &&
327 p->port_id < p->designated_port) {
328 br_become_designated_port(p);
329 br_port_state_selection(p->br);
335 /* called under bridge lock */
336 int br_stp_set_path_cost(struct net_bridge_port *p, unsigned long path_cost)
338 if (path_cost < BR_MIN_PATH_COST ||
339 path_cost > BR_MAX_PATH_COST)
342 p->flags |= BR_ADMIN_COST;
343 p->path_cost = path_cost;
344 br_configuration_update(p->br);
345 br_port_state_selection(p->br);
349 ssize_t br_show_bridge_id(char *buf, const struct bridge_id *id)
351 return sprintf(buf, "%.2x%.2x.%.2x%.2x%.2x%.2x%.2x%.2x\n",
352 id->prio[0], id->prio[1],
353 id->addr[0], id->addr[1], id->addr[2],
354 id->addr[3], id->addr[4], id->addr[5]);