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/etherdevice.h>
16 #include <linux/rtnetlink.h>
17
18 #include "br_private.h"
19 #include "br_private_stp.h"
20
21
22 /* Port id is composed of priority and port number.
23 * NB: least significant bits of priority are dropped to
24 * make room for more ports.
25 */
br_make_port_id(__u8 priority,__u16 port_no)26 static inline port_id br_make_port_id(__u8 priority, __u16 port_no)
27 {
28 return ((u16)priority << BR_PORT_BITS)
29 | (port_no & ((1<<BR_PORT_BITS)-1));
30 }
31
32 /* called under bridge lock */
br_init_port(struct net_bridge_port * p)33 void br_init_port(struct net_bridge_port *p)
34 {
35 p->port_id = br_make_port_id(p->priority, p->port_no);
36 br_become_designated_port(p);
37 p->state = BR_STATE_BLOCKING;
38 p->topology_change_ack = 0;
39 p->config_pending = 0;
40 }
41
42 /* called under bridge lock */
br_stp_enable_bridge(struct net_bridge * br)43 void br_stp_enable_bridge(struct net_bridge *br)
44 {
45 struct net_bridge_port *p;
46
47 spin_lock_bh(&br->lock);
48 mod_timer(&br->hello_timer, jiffies + br->hello_time);
49 mod_timer(&br->gc_timer, jiffies + HZ/10);
50
51 br_config_bpdu_generation(br);
52
53 list_for_each_entry(p, &br->port_list, list) {
54 if ((p->dev->flags & IFF_UP) && netif_carrier_ok(p->dev))
55 br_stp_enable_port(p);
56
57 }
58 spin_unlock_bh(&br->lock);
59 }
60
61 /* NO locks held */
br_stp_disable_bridge(struct net_bridge * br)62 void br_stp_disable_bridge(struct net_bridge *br)
63 {
64 struct net_bridge_port *p;
65
66 spin_lock_bh(&br->lock);
67 list_for_each_entry(p, &br->port_list, list) {
68 if (p->state != BR_STATE_DISABLED)
69 br_stp_disable_port(p);
70
71 }
72
73 br->topology_change = 0;
74 br->topology_change_detected = 0;
75 spin_unlock_bh(&br->lock);
76
77 del_timer_sync(&br->hello_timer);
78 del_timer_sync(&br->topology_change_timer);
79 del_timer_sync(&br->tcn_timer);
80 del_timer_sync(&br->gc_timer);
81 }
82
83 /* called under bridge lock */
br_stp_enable_port(struct net_bridge_port * p)84 void br_stp_enable_port(struct net_bridge_port *p)
85 {
86 br_init_port(p);
87 br_port_state_selection(p->br);
88 }
89
90 /* called under bridge lock */
br_stp_disable_port(struct net_bridge_port * p)91 void br_stp_disable_port(struct net_bridge_port *p)
92 {
93 struct net_bridge *br;
94 int wasroot;
95
96 br = p->br;
97 printk(KERN_INFO "%s: port %i(%s) entering %s state\n",
98 br->dev->name, p->port_no, p->dev->name, "disabled");
99
100 wasroot = br_is_root_bridge(br);
101 br_become_designated_port(p);
102 p->state = BR_STATE_DISABLED;
103 p->topology_change_ack = 0;
104 p->config_pending = 0;
105
106 del_timer(&p->message_age_timer);
107 del_timer(&p->forward_delay_timer);
108 del_timer(&p->hold_timer);
109
110 br_fdb_delete_by_port(br, p, 0);
111
112 br_configuration_update(br);
113
114 br_port_state_selection(br);
115
116 if (br_is_root_bridge(br) && !wasroot)
117 br_become_root_bridge(br);
118 }
119
br_stp_start(struct net_bridge * br)120 static void br_stp_start(struct net_bridge *br)
121 {
122 int r;
123 char *argv[] = { BR_STP_PROG, br->dev->name, "start", NULL };
124 char *envp[] = { NULL };
125
126 r = call_usermodehelper(BR_STP_PROG, argv, envp, UMH_WAIT_PROC);
127 if (r == 0) {
128 br->stp_enabled = BR_USER_STP;
129 printk(KERN_INFO "%s: userspace STP started\n", br->dev->name);
130 } else {
131 br->stp_enabled = BR_KERNEL_STP;
132 printk(KERN_INFO "%s: starting userspace STP failed, "
133 "starting kernel STP\n", br->dev->name);
134
135 /* To start timers on any ports left in blocking */
136 spin_lock_bh(&br->lock);
137 br_port_state_selection(br);
138 spin_unlock_bh(&br->lock);
139 }
140 }
141
br_stp_stop(struct net_bridge * br)142 static void br_stp_stop(struct net_bridge *br)
143 {
144 int r;
145 char *argv[] = { BR_STP_PROG, br->dev->name, "stop", NULL };
146 char *envp[] = { NULL };
147
148 if (br->stp_enabled == BR_USER_STP) {
149 r = call_usermodehelper(BR_STP_PROG, argv, envp, 1);
150 printk(KERN_INFO "%s: userspace STP stopped, return code %d\n",
151 br->dev->name, r);
152
153
154 /* To start timers on any ports left in blocking */
155 spin_lock_bh(&br->lock);
156 br_port_state_selection(br);
157 spin_unlock_bh(&br->lock);
158 }
159
160 br->stp_enabled = BR_NO_STP;
161 }
162
br_stp_set_enabled(struct net_bridge * br,unsigned long val)163 void br_stp_set_enabled(struct net_bridge *br, unsigned long val)
164 {
165 ASSERT_RTNL();
166
167 if (val) {
168 if (br->stp_enabled == BR_NO_STP)
169 br_stp_start(br);
170 } else {
171 if (br->stp_enabled != BR_NO_STP)
172 br_stp_stop(br);
173 }
174 }
175
176 /* called under bridge lock */
br_stp_change_bridge_id(struct net_bridge * br,const unsigned char * addr)177 void br_stp_change_bridge_id(struct net_bridge *br, const unsigned char *addr)
178 {
179 /* should be aligned on 2 bytes for compare_ether_addr() */
180 unsigned short oldaddr_aligned[ETH_ALEN >> 1];
181 unsigned char *oldaddr = (unsigned char *)oldaddr_aligned;
182 struct net_bridge_port *p;
183 int wasroot;
184
185 wasroot = br_is_root_bridge(br);
186
187 memcpy(oldaddr, br->bridge_id.addr, ETH_ALEN);
188 memcpy(br->bridge_id.addr, addr, ETH_ALEN);
189 memcpy(br->dev->dev_addr, addr, ETH_ALEN);
190
191 list_for_each_entry(p, &br->port_list, list) {
192 if (!compare_ether_addr(p->designated_bridge.addr, oldaddr))
193 memcpy(p->designated_bridge.addr, addr, ETH_ALEN);
194
195 if (!compare_ether_addr(p->designated_root.addr, oldaddr))
196 memcpy(p->designated_root.addr, addr, ETH_ALEN);
197
198 }
199
200 br_configuration_update(br);
201 br_port_state_selection(br);
202 if (br_is_root_bridge(br) && !wasroot)
203 br_become_root_bridge(br);
204 }
205
206 /* should be aligned on 2 bytes for compare_ether_addr() */
207 static const unsigned short br_mac_zero_aligned[ETH_ALEN >> 1];
208
209 /* called under bridge lock */
br_stp_recalculate_bridge_id(struct net_bridge * br)210 void br_stp_recalculate_bridge_id(struct net_bridge *br)
211 {
212 const unsigned char *br_mac_zero =
213 (const unsigned char *)br_mac_zero_aligned;
214 const unsigned char *addr = br_mac_zero;
215 struct net_bridge_port *p;
216
217 /* user has chosen a value so keep it */
218 if (br->flags & BR_SET_MAC_ADDR)
219 return;
220
221 list_for_each_entry(p, &br->port_list, list) {
222 if (addr == br_mac_zero ||
223 memcmp(p->dev->dev_addr, addr, ETH_ALEN) < 0)
224 addr = p->dev->dev_addr;
225
226 }
227
228 if (compare_ether_addr(br->bridge_id.addr, addr))
229 br_stp_change_bridge_id(br, addr);
230 }
231
232 /* called under bridge lock */
br_stp_set_bridge_priority(struct net_bridge * br,u16 newprio)233 void br_stp_set_bridge_priority(struct net_bridge *br, u16 newprio)
234 {
235 struct net_bridge_port *p;
236 int wasroot;
237
238 wasroot = br_is_root_bridge(br);
239
240 list_for_each_entry(p, &br->port_list, list) {
241 if (p->state != BR_STATE_DISABLED &&
242 br_is_designated_port(p)) {
243 p->designated_bridge.prio[0] = (newprio >> 8) & 0xFF;
244 p->designated_bridge.prio[1] = newprio & 0xFF;
245 }
246
247 }
248
249 br->bridge_id.prio[0] = (newprio >> 8) & 0xFF;
250 br->bridge_id.prio[1] = newprio & 0xFF;
251 br_configuration_update(br);
252 br_port_state_selection(br);
253 if (br_is_root_bridge(br) && !wasroot)
254 br_become_root_bridge(br);
255 }
256
257 /* called under bridge lock */
br_stp_set_port_priority(struct net_bridge_port * p,u8 newprio)258 void br_stp_set_port_priority(struct net_bridge_port *p, u8 newprio)
259 {
260 port_id new_port_id = br_make_port_id(newprio, p->port_no);
261
262 if (br_is_designated_port(p))
263 p->designated_port = new_port_id;
264
265 p->port_id = new_port_id;
266 p->priority = newprio;
267 if (!memcmp(&p->br->bridge_id, &p->designated_bridge, 8) &&
268 p->port_id < p->designated_port) {
269 br_become_designated_port(p);
270 br_port_state_selection(p->br);
271 }
272 }
273
274 /* called under bridge lock */
br_stp_set_path_cost(struct net_bridge_port * p,u32 path_cost)275 void br_stp_set_path_cost(struct net_bridge_port *p, u32 path_cost)
276 {
277 p->path_cost = path_cost;
278 br_configuration_update(p->br);
279 br_port_state_selection(p->br);
280 }
281
br_show_bridge_id(char * buf,const struct bridge_id * id)282 ssize_t br_show_bridge_id(char *buf, const struct bridge_id *id)
283 {
284 return sprintf(buf, "%.2x%.2x.%.2x%.2x%.2x%.2x%.2x%.2x\n",
285 id->prio[0], id->prio[1],
286 id->addr[0], id->addr[1], id->addr[2],
287 id->addr[3], id->addr[4], id->addr[5]);
288 }
289