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 */
26static 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 */
33void 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 */
43void 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 */
62void 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 */
84void br_stp_enable_port(struct net_bridge_port *p)
85{
86	br_init_port(p);
87	br_port_state_selection(p->br);
88	br_log_state(p);
89}
90
91/* called under bridge lock */
92void br_stp_disable_port(struct net_bridge_port *p)
93{
94	struct net_bridge *br = p->br;
95	int wasroot;
96
97	br_log_state(p);
98
99	wasroot = br_is_root_bridge(br);
100	br_become_designated_port(p);
101	p->state = BR_STATE_DISABLED;
102	p->topology_change_ack = 0;
103	p->config_pending = 0;
104
105	del_timer(&p->message_age_timer);
106	del_timer(&p->forward_delay_timer);
107	del_timer(&p->hold_timer);
108
109	br_fdb_delete_by_port(br, p, 0);
110	br_multicast_disable_port(p);
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
120static 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		br_debug(br, "userspace STP started\n");
130	} else {
131		br->stp_enabled = BR_KERNEL_STP;
132		br_debug(br, "using kernel STP\n");
133
134		/* To start timers on any ports left in blocking */
135		spin_lock_bh(&br->lock);
136		br_port_state_selection(br);
137		spin_unlock_bh(&br->lock);
138	}
139}
140
141static void br_stp_stop(struct net_bridge *br)
142{
143	int r;
144	char *argv[] = { BR_STP_PROG, br->dev->name, "stop", NULL };
145	char *envp[] = { NULL };
146
147	if (br->stp_enabled == BR_USER_STP) {
148		r = call_usermodehelper(BR_STP_PROG, argv, envp, 1);
149		br_info(br, "userspace STP stopped, return code %d\n", r);
150
151		/* To start timers on any ports left in blocking */
152		spin_lock_bh(&br->lock);
153		br_port_state_selection(br);
154		spin_unlock_bh(&br->lock);
155	}
156
157	br->stp_enabled = BR_NO_STP;
158}
159
160void br_stp_set_enabled(struct net_bridge *br, unsigned long val)
161{
162	ASSERT_RTNL();
163
164	if (val) {
165		if (br->stp_enabled == BR_NO_STP)
166			br_stp_start(br);
167	} else {
168		if (br->stp_enabled != BR_NO_STP)
169			br_stp_stop(br);
170	}
171}
172
173/* called under bridge lock */
174void br_stp_change_bridge_id(struct net_bridge *br, const unsigned char *addr)
175{
176	/* should be aligned on 2 bytes for compare_ether_addr() */
177	unsigned short oldaddr_aligned[ETH_ALEN >> 1];
178	unsigned char *oldaddr = (unsigned char *)oldaddr_aligned;
179	struct net_bridge_port *p;
180	int wasroot;
181
182	wasroot = br_is_root_bridge(br);
183
184	memcpy(oldaddr, br->bridge_id.addr, ETH_ALEN);
185	memcpy(br->bridge_id.addr, addr, ETH_ALEN);
186	memcpy(br->dev->dev_addr, addr, ETH_ALEN);
187
188	list_for_each_entry(p, &br->port_list, list) {
189		if (!compare_ether_addr(p->designated_bridge.addr, oldaddr))
190			memcpy(p->designated_bridge.addr, addr, ETH_ALEN);
191
192		if (!compare_ether_addr(p->designated_root.addr, oldaddr))
193			memcpy(p->designated_root.addr, addr, ETH_ALEN);
194
195	}
196
197	br_configuration_update(br);
198	br_port_state_selection(br);
199	if (br_is_root_bridge(br) && !wasroot)
200		br_become_root_bridge(br);
201}
202
203/* should be aligned on 2 bytes for compare_ether_addr() */
204static const unsigned short br_mac_zero_aligned[ETH_ALEN >> 1];
205
206/* called under bridge lock */
207void br_stp_recalculate_bridge_id(struct net_bridge *br)
208{
209	const unsigned char *br_mac_zero =
210			(const unsigned char *)br_mac_zero_aligned;
211	const unsigned char *addr = br_mac_zero;
212	struct net_bridge_port *p;
213
214	/* user has chosen a value so keep it */
215	if (br->flags & BR_SET_MAC_ADDR)
216		return;
217
218	list_for_each_entry(p, &br->port_list, list) {
219		/* foxconn Bob removed start, always use first added if's mac as bridge mac address */
220		#if 0
221		if (addr == br_mac_zero ||
222		    memcmp(p->dev->dev_addr, addr, ETH_ALEN) < 0)
223		#endif
224		/* foxconn Bob removed end */
225			addr = p->dev->dev_addr;
226
227	}
228
229	if (compare_ether_addr(br->bridge_id.addr, addr))
230		br_stp_change_bridge_id(br, addr);
231}
232
233/* called under bridge lock */
234void br_stp_set_bridge_priority(struct net_bridge *br, u16 newprio)
235{
236	struct net_bridge_port *p;
237	int wasroot;
238
239	wasroot = br_is_root_bridge(br);
240
241	list_for_each_entry(p, &br->port_list, list) {
242		if (p->state != BR_STATE_DISABLED &&
243		    br_is_designated_port(p)) {
244			p->designated_bridge.prio[0] = (newprio >> 8) & 0xFF;
245			p->designated_bridge.prio[1] = newprio & 0xFF;
246		}
247
248	}
249
250	br->bridge_id.prio[0] = (newprio >> 8) & 0xFF;
251	br->bridge_id.prio[1] = newprio & 0xFF;
252	br_configuration_update(br);
253	br_port_state_selection(br);
254	if (br_is_root_bridge(br) && !wasroot)
255		br_become_root_bridge(br);
256}
257
258/* called under bridge lock */
259void br_stp_set_port_priority(struct net_bridge_port *p, u8 newprio)
260{
261	port_id new_port_id = br_make_port_id(newprio, p->port_no);
262
263	if (br_is_designated_port(p))
264		p->designated_port = new_port_id;
265
266	p->port_id = new_port_id;
267	p->priority = newprio;
268	if (!memcmp(&p->br->bridge_id, &p->designated_bridge, 8) &&
269	    p->port_id < p->designated_port) {
270		br_become_designated_port(p);
271		br_port_state_selection(p->br);
272	}
273}
274
275/* called under bridge lock */
276void br_stp_set_path_cost(struct net_bridge_port *p, u32 path_cost)
277{
278	p->path_cost = path_cost;
279	br_configuration_update(p->br);
280	br_port_state_selection(p->br);
281}
282
283ssize_t br_show_bridge_id(char *buf, const struct bridge_id *id)
284{
285	return sprintf(buf, "%.2x%.2x.%.2x%.2x%.2x%.2x%.2x%.2x\n",
286	       id->prio[0], id->prio[1],
287	       id->addr[0], id->addr[1], id->addr[2],
288	       id->addr[3], id->addr[4], id->addr[5]);
289}
290