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>
19 #include "br_private.h"
20 #include "br_private_stp.h"
23 /* Port id is composed of priority and port number.
24 * NB: some bits of priority are dropped to
25 * make room for more ports.
27 static inline port_id br_make_port_id(__u8 priority, __u16 port_no)
29 return ((u16)priority << BR_PORT_BITS)
30 | (port_no & ((1<<BR_PORT_BITS)-1));
33 #define BR_MAX_PORT_PRIORITY ((u16)~0 >> BR_PORT_BITS)
35 /* called under bridge lock */
36 void br_init_port(struct net_bridge_port *p)
38 p->port_id = br_make_port_id(p->priority, p->port_no);
39 br_become_designated_port(p);
40 p->state = BR_STATE_BLOCKING;
41 p->topology_change_ack = 0;
42 p->config_pending = 0;
45 /* called under bridge lock */
46 void br_stp_enable_bridge(struct net_bridge *br)
48 struct net_bridge_port *p;
50 spin_lock_bh(&br->lock);
51 mod_timer(&br->hello_timer, jiffies + br->hello_time);
52 mod_timer(&br->gc_timer, jiffies + HZ/10);
54 br_config_bpdu_generation(br);
56 list_for_each_entry(p, &br->port_list, list) {
57 if ((p->dev->flags & IFF_UP) && netif_carrier_ok(p->dev))
58 br_stp_enable_port(p);
61 spin_unlock_bh(&br->lock);
65 void br_stp_disable_bridge(struct net_bridge *br)
67 struct net_bridge_port *p;
69 spin_lock_bh(&br->lock);
70 list_for_each_entry(p, &br->port_list, list) {
71 if (p->state != BR_STATE_DISABLED)
72 br_stp_disable_port(p);
76 br->topology_change = 0;
77 br->topology_change_detected = 0;
78 spin_unlock_bh(&br->lock);
80 del_timer_sync(&br->hello_timer);
81 del_timer_sync(&br->topology_change_timer);
82 del_timer_sync(&br->tcn_timer);
83 del_timer_sync(&br->gc_timer);
86 /* called under bridge lock */
87 void br_stp_enable_port(struct net_bridge_port *p)
90 br_port_state_selection(p->br);
92 br_ifinfo_notify(RTM_NEWLINK, p);
95 /* called under bridge lock */
96 void br_stp_disable_port(struct net_bridge_port *p)
98 struct net_bridge *br = p->br;
103 wasroot = br_is_root_bridge(br);
104 br_become_designated_port(p);
105 p->state = BR_STATE_DISABLED;
106 p->topology_change_ack = 0;
107 p->config_pending = 0;
109 br_ifinfo_notify(RTM_NEWLINK, p);
111 del_timer(&p->message_age_timer);
112 del_timer(&p->forward_delay_timer);
113 del_timer(&p->hold_timer);
115 br_fdb_delete_by_port(br, p, 0);
116 br_multicast_disable_port(p);
118 br_configuration_update(br);
120 br_port_state_selection(br);
122 if (br_is_root_bridge(br) && !wasroot)
123 br_become_root_bridge(br);
126 static void br_stp_start(struct net_bridge *br)
129 char *argv[] = { BR_STP_PROG, br->dev->name, "start", NULL };
130 char *envp[] = { NULL };
132 if (net_eq(dev_net(br->dev), &init_net))
133 r = call_usermodehelper(BR_STP_PROG, argv, envp, UMH_WAIT_PROC);
137 br->stp_enabled = BR_USER_STP;
138 br_debug(br, "userspace STP started\n");
140 br->stp_enabled = BR_KERNEL_STP;
141 br_debug(br, "using kernel STP\n");
143 /* To start timers on any ports left in blocking */
144 spin_lock_bh(&br->lock);
145 br_port_state_selection(br);
146 spin_unlock_bh(&br->lock);
150 static void br_stp_stop(struct net_bridge *br)
153 char *argv[] = { BR_STP_PROG, br->dev->name, "stop", NULL };
154 char *envp[] = { NULL };
156 if (br->stp_enabled == BR_USER_STP) {
157 r = call_usermodehelper(BR_STP_PROG, argv, envp, UMH_WAIT_PROC);
158 br_info(br, "userspace STP stopped, return code %d\n", r);
160 /* To start timers on any ports left in blocking */
161 spin_lock_bh(&br->lock);
162 br_port_state_selection(br);
163 spin_unlock_bh(&br->lock);
166 br->stp_enabled = BR_NO_STP;
169 void br_stp_set_enabled(struct net_bridge *br, unsigned long val)
174 if (br->stp_enabled == BR_NO_STP)
177 if (br->stp_enabled != BR_NO_STP)
182 /* called under bridge lock */
183 void br_stp_change_bridge_id(struct net_bridge *br, const unsigned char *addr)
185 /* should be aligned on 2 bytes for compare_ether_addr() */
186 unsigned short oldaddr_aligned[ETH_ALEN >> 1];
187 unsigned char *oldaddr = (unsigned char *)oldaddr_aligned;
188 struct net_bridge_port *p;
191 wasroot = br_is_root_bridge(br);
193 memcpy(oldaddr, br->bridge_id.addr, ETH_ALEN);
194 memcpy(br->bridge_id.addr, addr, ETH_ALEN);
195 memcpy(br->dev->dev_addr, addr, ETH_ALEN);
197 list_for_each_entry(p, &br->port_list, list) {
198 if (!compare_ether_addr(p->designated_bridge.addr, oldaddr))
199 memcpy(p->designated_bridge.addr, addr, ETH_ALEN);
201 if (!compare_ether_addr(p->designated_root.addr, oldaddr))
202 memcpy(p->designated_root.addr, addr, ETH_ALEN);
206 br_configuration_update(br);
207 br_port_state_selection(br);
208 if (br_is_root_bridge(br) && !wasroot)
209 br_become_root_bridge(br);
212 /* should be aligned on 2 bytes for compare_ether_addr() */
213 static const unsigned short br_mac_zero_aligned[ETH_ALEN >> 1];
215 /* called under bridge lock */
216 bool br_stp_recalculate_bridge_id(struct net_bridge *br)
218 const unsigned char *br_mac_zero =
219 (const unsigned char *)br_mac_zero_aligned;
220 const unsigned char *addr = br_mac_zero;
221 struct net_bridge_port *p;
223 /* user has chosen a value so keep it */
224 if (br->flags & BR_SET_MAC_ADDR)
227 list_for_each_entry(p, &br->port_list, list) {
228 if (addr == br_mac_zero ||
229 memcmp(p->dev->dev_addr, addr, ETH_ALEN) < 0)
230 addr = p->dev->dev_addr;
234 if (compare_ether_addr(br->bridge_id.addr, addr) == 0)
235 return false; /* no change */
237 br_stp_change_bridge_id(br, addr);
241 /* Acquires and releases bridge lock */
242 void br_stp_set_bridge_priority(struct net_bridge *br, u16 newprio)
244 struct net_bridge_port *p;
247 spin_lock_bh(&br->lock);
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);
265 spin_unlock_bh(&br->lock);
268 /* called under bridge lock */
269 int br_stp_set_port_priority(struct net_bridge_port *p, unsigned long newprio)
273 if (newprio > BR_MAX_PORT_PRIORITY)
276 new_port_id = br_make_port_id(newprio, p->port_no);
277 if (br_is_designated_port(p))
278 p->designated_port = new_port_id;
280 p->port_id = new_port_id;
281 p->priority = newprio;
282 if (!memcmp(&p->br->bridge_id, &p->designated_bridge, 8) &&
283 p->port_id < p->designated_port) {
284 br_become_designated_port(p);
285 br_port_state_selection(p->br);
291 /* called under bridge lock */
292 int br_stp_set_path_cost(struct net_bridge_port *p, unsigned long path_cost)
294 if (path_cost < BR_MIN_PATH_COST ||
295 path_cost > BR_MAX_PATH_COST)
298 p->path_cost = path_cost;
299 br_configuration_update(p->br);
300 br_port_state_selection(p->br);
304 ssize_t br_show_bridge_id(char *buf, const struct bridge_id *id)
306 return sprintf(buf, "%.2x%.2x.%.2x%.2x%.2x%.2x%.2x%.2x\n",
307 id->prio[0], id->prio[1],
308 id->addr[0], id->addr[1], id->addr[2],
309 id->addr[3], id->addr[4], id->addr[5]);