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/etherdevice.h>
16 #include <linux/rtnetlink.h>
18 #include "br_private.h"
19 #include "br_private_stp.h"
22 /* Port id is composed of priority and port number.
23 * NB: some bits of priority are dropped to
24 * make room for more ports.
26 static inline port_id br_make_port_id(__u8 priority, __u16 port_no)
28 return ((u16)priority << BR_PORT_BITS)
29 | (port_no & ((1<<BR_PORT_BITS)-1));
32 #define BR_MAX_PORT_PRIORITY ((u16)~0 >> BR_PORT_BITS)
34 /* called under bridge lock */
35 void br_init_port(struct net_bridge_port *p)
37 p->port_id = br_make_port_id(p->priority, p->port_no);
38 br_become_designated_port(p);
39 p->state = BR_STATE_BLOCKING;
40 p->topology_change_ack = 0;
41 p->config_pending = 0;
44 /* called under bridge lock */
45 void br_stp_enable_bridge(struct net_bridge *br)
47 struct net_bridge_port *p;
49 spin_lock_bh(&br->lock);
50 mod_timer(&br->hello_timer, jiffies + br->hello_time);
51 mod_timer(&br->gc_timer, jiffies + HZ/10);
53 br_config_bpdu_generation(br);
55 list_for_each_entry(p, &br->port_list, list) {
56 if ((p->dev->flags & IFF_UP) && netif_carrier_ok(p->dev))
57 br_stp_enable_port(p);
60 spin_unlock_bh(&br->lock);
64 void br_stp_disable_bridge(struct net_bridge *br)
66 struct net_bridge_port *p;
68 spin_lock_bh(&br->lock);
69 list_for_each_entry(p, &br->port_list, list) {
70 if (p->state != BR_STATE_DISABLED)
71 br_stp_disable_port(p);
75 br->topology_change = 0;
76 br->topology_change_detected = 0;
77 spin_unlock_bh(&br->lock);
79 del_timer_sync(&br->hello_timer);
80 del_timer_sync(&br->topology_change_timer);
81 del_timer_sync(&br->tcn_timer);
82 del_timer_sync(&br->gc_timer);
85 /* called under bridge lock */
86 void br_stp_enable_port(struct net_bridge_port *p)
89 br_port_state_selection(p->br);
93 /* called under bridge lock */
94 void br_stp_disable_port(struct net_bridge_port *p)
96 struct net_bridge *br = p->br;
101 wasroot = br_is_root_bridge(br);
102 br_become_designated_port(p);
103 p->state = BR_STATE_DISABLED;
104 p->topology_change_ack = 0;
105 p->config_pending = 0;
107 del_timer(&p->message_age_timer);
108 del_timer(&p->forward_delay_timer);
109 del_timer(&p->hold_timer);
111 br_fdb_delete_by_port(br, p, 0);
112 br_multicast_disable_port(p);
114 br_configuration_update(br);
116 br_port_state_selection(br);
118 if (br_is_root_bridge(br) && !wasroot)
119 br_become_root_bridge(br);
122 static void br_stp_start(struct net_bridge *br)
125 char *argv[] = { BR_STP_PROG, br->dev->name, "start", NULL };
126 char *envp[] = { NULL };
128 r = call_usermodehelper(BR_STP_PROG, argv, envp, UMH_WAIT_PROC);
130 spin_lock_bh(&br->lock);
132 if (br->bridge_forward_delay < BR_MIN_FORWARD_DELAY)
133 __br_set_forward_delay(br, BR_MIN_FORWARD_DELAY);
134 else if (br->bridge_forward_delay < BR_MAX_FORWARD_DELAY)
135 __br_set_forward_delay(br, BR_MAX_FORWARD_DELAY);
138 br->stp_enabled = BR_USER_STP;
139 br_debug(br, "userspace STP started\n");
141 br->stp_enabled = BR_KERNEL_STP;
142 br_debug(br, "using kernel STP\n");
144 /* To start timers on any ports left in blocking */
145 br_port_state_selection(br);
148 spin_unlock_bh(&br->lock);
151 static void br_stp_stop(struct net_bridge *br)
154 char *argv[] = { BR_STP_PROG, br->dev->name, "stop", NULL };
155 char *envp[] = { NULL };
157 if (br->stp_enabled == BR_USER_STP) {
158 r = call_usermodehelper(BR_STP_PROG, argv, envp, UMH_WAIT_PROC);
159 br_info(br, "userspace STP stopped, return code %d\n", r);
161 /* To start timers on any ports left in blocking */
162 spin_lock_bh(&br->lock);
163 br_port_state_selection(br);
164 spin_unlock_bh(&br->lock);
167 br->stp_enabled = BR_NO_STP;
170 void br_stp_set_enabled(struct net_bridge *br, unsigned long val)
175 if (br->stp_enabled == BR_NO_STP)
178 if (br->stp_enabled != BR_NO_STP)
183 /* called under bridge lock */
184 void br_stp_change_bridge_id(struct net_bridge *br, const unsigned char *addr)
186 /* should be aligned on 2 bytes for compare_ether_addr() */
187 unsigned short oldaddr_aligned[ETH_ALEN >> 1];
188 unsigned char *oldaddr = (unsigned char *)oldaddr_aligned;
189 struct net_bridge_port *p;
192 wasroot = br_is_root_bridge(br);
194 memcpy(oldaddr, br->bridge_id.addr, ETH_ALEN);
195 memcpy(br->bridge_id.addr, addr, ETH_ALEN);
196 memcpy(br->dev->dev_addr, addr, ETH_ALEN);
198 list_for_each_entry(p, &br->port_list, list) {
199 if (!compare_ether_addr(p->designated_bridge.addr, oldaddr))
200 memcpy(p->designated_bridge.addr, addr, ETH_ALEN);
202 if (!compare_ether_addr(p->designated_root.addr, oldaddr))
203 memcpy(p->designated_root.addr, addr, ETH_ALEN);
207 br_configuration_update(br);
208 br_port_state_selection(br);
209 if (br_is_root_bridge(br) && !wasroot)
210 br_become_root_bridge(br);
213 /* should be aligned on 2 bytes for compare_ether_addr() */
214 static const unsigned short br_mac_zero_aligned[ETH_ALEN >> 1];
216 /* called under bridge lock */
217 bool br_stp_recalculate_bridge_id(struct net_bridge *br)
219 const unsigned char *br_mac_zero =
220 (const unsigned char *)br_mac_zero_aligned;
221 const unsigned char *addr = br_mac_zero;
222 struct net_bridge_port *p;
224 /* user has chosen a value so keep it */
225 if (br->flags & BR_SET_MAC_ADDR)
228 list_for_each_entry(p, &br->port_list, list) {
229 if (addr == br_mac_zero ||
230 memcmp(p->dev->dev_addr, addr, ETH_ALEN) < 0)
231 addr = p->dev->dev_addr;
235 if (compare_ether_addr(br->bridge_id.addr, addr) == 0)
236 return false; /* no change */
238 br_stp_change_bridge_id(br, addr);
242 /* called under bridge lock */
243 void br_stp_set_bridge_priority(struct net_bridge *br, u16 newprio)
245 struct net_bridge_port *p;
248 wasroot = br_is_root_bridge(br);
250 list_for_each_entry(p, &br->port_list, list) {
251 if (p->state != BR_STATE_DISABLED &&
252 br_is_designated_port(p)) {
253 p->designated_bridge.prio[0] = (newprio >> 8) & 0xFF;
254 p->designated_bridge.prio[1] = newprio & 0xFF;
259 br->bridge_id.prio[0] = (newprio >> 8) & 0xFF;
260 br->bridge_id.prio[1] = newprio & 0xFF;
261 br_configuration_update(br);
262 br_port_state_selection(br);
263 if (br_is_root_bridge(br) && !wasroot)
264 br_become_root_bridge(br);
267 /* called under bridge lock */
268 int br_stp_set_port_priority(struct net_bridge_port *p, unsigned long newprio)
272 if (newprio > BR_MAX_PORT_PRIORITY)
275 new_port_id = br_make_port_id(newprio, p->port_no);
276 if (br_is_designated_port(p))
277 p->designated_port = new_port_id;
279 p->port_id = new_port_id;
280 p->priority = newprio;
281 if (!memcmp(&p->br->bridge_id, &p->designated_bridge, 8) &&
282 p->port_id < p->designated_port) {
283 br_become_designated_port(p);
284 br_port_state_selection(p->br);
290 /* called under bridge lock */
291 int br_stp_set_path_cost(struct net_bridge_port *p, unsigned long path_cost)
293 if (path_cost < BR_MIN_PATH_COST ||
294 path_cost > BR_MAX_PATH_COST)
297 p->path_cost = path_cost;
298 br_configuration_update(p->br);
299 br_port_state_selection(p->br);
303 ssize_t br_show_bridge_id(char *buf, const struct bridge_id *id)
305 return sprintf(buf, "%.2x%.2x.%.2x%.2x%.2x%.2x%.2x%.2x\n",
306 id->prio[0], id->prio[1],
307 id->addr[0], id->addr[1], id->addr[2],
308 id->addr[3], id->addr[4], id->addr[5]);