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14#include <linux/kernel.h>
15#include <linux/netfilter_bridge.h>
16#include <linux/etherdevice.h>
17#include <linux/llc.h>
18#include <linux/slab.h>
19#include <linux/pkt_sched.h>
20#include <net/net_namespace.h>
21#include <net/llc.h>
22#include <net/llc_pdu.h>
23#include <net/stp.h>
24#include <asm/unaligned.h>
25
26#include "br_private.h"
27#include "br_private_stp.h"
28
29#define STP_HZ 256
30
31#define LLC_RESERVE sizeof(struct llc_pdu_un)
32
33static void br_send_bpdu(struct net_bridge_port *p,
34 const unsigned char *data, int length)
35{
36 struct sk_buff *skb;
37
38 skb = dev_alloc_skb(length+LLC_RESERVE);
39 if (!skb)
40 return;
41
42 skb->dev = p->dev;
43 skb->protocol = htons(ETH_P_802_2);
44 skb->priority = TC_PRIO_CONTROL;
45
46 skb_reserve(skb, LLC_RESERVE);
47 memcpy(__skb_put(skb, length), data, length);
48
49 llc_pdu_header_init(skb, LLC_PDU_TYPE_U, LLC_SAP_BSPAN,
50 LLC_SAP_BSPAN, LLC_PDU_CMD);
51 llc_pdu_init_as_ui_cmd(skb);
52
53 llc_mac_hdr_init(skb, p->dev->dev_addr, p->br->group_addr);
54
55 skb_reset_mac_header(skb);
56
57 NF_HOOK(NFPROTO_BRIDGE, NF_BR_LOCAL_OUT, skb, NULL, skb->dev,
58 dev_queue_xmit);
59}
60
61static inline void br_set_ticks(unsigned char *dest, int j)
62{
63 unsigned long ticks = (STP_HZ * j)/ HZ;
64
65 put_unaligned_be16(ticks, dest);
66}
67
68static inline int br_get_ticks(const unsigned char *src)
69{
70 unsigned long ticks = get_unaligned_be16(src);
71
72 return DIV_ROUND_UP(ticks * HZ, STP_HZ);
73}
74
75
76void br_send_config_bpdu(struct net_bridge_port *p, struct br_config_bpdu *bpdu)
77{
78 unsigned char buf[35];
79
80 if (p->br->stp_enabled != BR_KERNEL_STP)
81 return;
82
83 buf[0] = 0;
84 buf[1] = 0;
85 buf[2] = 0;
86 buf[3] = BPDU_TYPE_CONFIG;
87 buf[4] = (bpdu->topology_change ? 0x01 : 0) |
88 (bpdu->topology_change_ack ? 0x80 : 0);
89 buf[5] = bpdu->root.prio[0];
90 buf[6] = bpdu->root.prio[1];
91 buf[7] = bpdu->root.addr[0];
92 buf[8] = bpdu->root.addr[1];
93 buf[9] = bpdu->root.addr[2];
94 buf[10] = bpdu->root.addr[3];
95 buf[11] = bpdu->root.addr[4];
96 buf[12] = bpdu->root.addr[5];
97 buf[13] = (bpdu->root_path_cost >> 24) & 0xFF;
98 buf[14] = (bpdu->root_path_cost >> 16) & 0xFF;
99 buf[15] = (bpdu->root_path_cost >> 8) & 0xFF;
100 buf[16] = bpdu->root_path_cost & 0xFF;
101 buf[17] = bpdu->bridge_id.prio[0];
102 buf[18] = bpdu->bridge_id.prio[1];
103 buf[19] = bpdu->bridge_id.addr[0];
104 buf[20] = bpdu->bridge_id.addr[1];
105 buf[21] = bpdu->bridge_id.addr[2];
106 buf[22] = bpdu->bridge_id.addr[3];
107 buf[23] = bpdu->bridge_id.addr[4];
108 buf[24] = bpdu->bridge_id.addr[5];
109 buf[25] = (bpdu->port_id >> 8) & 0xFF;
110 buf[26] = bpdu->port_id & 0xFF;
111
112 br_set_ticks(buf+27, bpdu->message_age);
113 br_set_ticks(buf+29, bpdu->max_age);
114 br_set_ticks(buf+31, bpdu->hello_time);
115 br_set_ticks(buf+33, bpdu->forward_delay);
116
117 br_send_bpdu(p, buf, 35);
118}
119
120
121void br_send_tcn_bpdu(struct net_bridge_port *p)
122{
123 unsigned char buf[4];
124
125 if (p->br->stp_enabled != BR_KERNEL_STP)
126 return;
127
128 buf[0] = 0;
129 buf[1] = 0;
130 buf[2] = 0;
131 buf[3] = BPDU_TYPE_TCN;
132 br_send_bpdu(p, buf, 4);
133}
134
135
136
137
138
139
140void br_stp_rcv(const struct stp_proto *proto, struct sk_buff *skb,
141 struct net_device *dev)
142{
143 const unsigned char *dest = eth_hdr(skb)->h_dest;
144 struct net_bridge_port *p;
145 struct net_bridge *br;
146 const unsigned char *buf;
147
148 if (!pskb_may_pull(skb, 4))
149 goto err;
150
151
152 buf = skb->data;
153 if (buf[0] != 0 || buf[1] != 0 || buf[2] != 0)
154 goto err;
155
156 p = br_port_get_rcu(dev);
157 if (!p)
158 goto err;
159
160 br = p->br;
161 spin_lock(&br->lock);
162
163 if (br->stp_enabled != BR_KERNEL_STP)
164 goto out;
165
166 if (!(br->dev->flags & IFF_UP))
167 goto out;
168
169 if (p->state == BR_STATE_DISABLED)
170 goto out;
171
172 if (!ether_addr_equal(dest, br->group_addr))
173 goto out;
174
175 if (p->flags & BR_BPDU_GUARD) {
176 br_notice(br, "BPDU received on blocked port %u(%s)\n",
177 (unsigned int) p->port_no, p->dev->name);
178 br_stp_disable_port(p);
179 goto out;
180 }
181
182 buf = skb_pull(skb, 3);
183
184 if (buf[0] == BPDU_TYPE_CONFIG) {
185 struct br_config_bpdu bpdu;
186
187 if (!pskb_may_pull(skb, 32))
188 goto out;
189
190 buf = skb->data;
191 bpdu.topology_change = (buf[1] & 0x01) ? 1 : 0;
192 bpdu.topology_change_ack = (buf[1] & 0x80) ? 1 : 0;
193
194 bpdu.root.prio[0] = buf[2];
195 bpdu.root.prio[1] = buf[3];
196 bpdu.root.addr[0] = buf[4];
197 bpdu.root.addr[1] = buf[5];
198 bpdu.root.addr[2] = buf[6];
199 bpdu.root.addr[3] = buf[7];
200 bpdu.root.addr[4] = buf[8];
201 bpdu.root.addr[5] = buf[9];
202 bpdu.root_path_cost =
203 (buf[10] << 24) |
204 (buf[11] << 16) |
205 (buf[12] << 8) |
206 buf[13];
207 bpdu.bridge_id.prio[0] = buf[14];
208 bpdu.bridge_id.prio[1] = buf[15];
209 bpdu.bridge_id.addr[0] = buf[16];
210 bpdu.bridge_id.addr[1] = buf[17];
211 bpdu.bridge_id.addr[2] = buf[18];
212 bpdu.bridge_id.addr[3] = buf[19];
213 bpdu.bridge_id.addr[4] = buf[20];
214 bpdu.bridge_id.addr[5] = buf[21];
215 bpdu.port_id = (buf[22] << 8) | buf[23];
216
217 bpdu.message_age = br_get_ticks(buf+24);
218 bpdu.max_age = br_get_ticks(buf+26);
219 bpdu.hello_time = br_get_ticks(buf+28);
220 bpdu.forward_delay = br_get_ticks(buf+30);
221
222 if (bpdu.message_age > bpdu.max_age) {
223 if (net_ratelimit())
224 br_notice(p->br,
225 "port %u config from %pM"
226 " (message_age %ul > max_age %ul)\n",
227 p->port_no,
228 eth_hdr(skb)->h_source,
229 bpdu.message_age, bpdu.max_age);
230 goto out;
231 }
232
233 br_received_config_bpdu(p, &bpdu);
234 } else if (buf[0] == BPDU_TYPE_TCN) {
235 br_received_tcn_bpdu(p);
236 }
237 out:
238 spin_unlock(&br->lock);
239 err:
240 kfree_skb(skb);
241}
242
