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16#include <linux/kernel.h>
17#include <linux/netfilter_bridge.h>
18#include <linux/etherdevice.h>
19#include <linux/llc.h>
20#include <net/net_namespace.h>
21#include <net/llc.h>
22#include <net/llc_pdu.h>
23#include <asm/unaligned.h>
24
25#include "br_private.h"
26#include "br_private_stp.h"
27
28#define STP_HZ 256
29
30#define LLC_RESERVE sizeof(struct llc_pdu_un)
31
32static void br_send_bpdu(struct net_bridge_port *p,
33 const unsigned char *data, int length)
34{
35 struct sk_buff *skb;
36
37 skb = dev_alloc_skb(length+LLC_RESERVE);
38 if (!skb)
39 return;
40
41 skb->dev = p->dev;
42 skb->protocol = htons(ETH_P_802_2);
43
44 skb_reserve(skb, LLC_RESERVE);
45 memcpy(__skb_put(skb, length), data, length);
46
47 llc_pdu_header_init(skb, LLC_PDU_TYPE_U, LLC_SAP_BSPAN,
48 LLC_SAP_BSPAN, LLC_PDU_CMD);
49 llc_pdu_init_as_ui_cmd(skb);
50
51 llc_mac_hdr_init(skb, p->dev->dev_addr, p->br->group_addr);
52
53 NF_HOOK(PF_BRIDGE, NF_BR_LOCAL_OUT, skb, NULL, skb->dev,
54 dev_queue_xmit);
55}
56
57static inline void br_set_ticks(unsigned char *dest, int j)
58{
59 unsigned long ticks = (STP_HZ * j)/ HZ;
60
61 put_unaligned(htons(ticks), (__be16 *)dest);
62}
63
64static inline int br_get_ticks(const unsigned char *src)
65{
66 unsigned long ticks = ntohs(get_unaligned((__be16 *)src));
67
68 return DIV_ROUND_UP(ticks * HZ, STP_HZ);
69}
70
71
72void br_send_config_bpdu(struct net_bridge_port *p, struct br_config_bpdu *bpdu)
73{
74 unsigned char buf[35];
75
76 if (p->br->stp_enabled != BR_KERNEL_STP)
77 return;
78
79 buf[0] = 0;
80 buf[1] = 0;
81 buf[2] = 0;
82 buf[3] = BPDU_TYPE_CONFIG;
83 buf[4] = (bpdu->topology_change ? 0x01 : 0) |
84 (bpdu->topology_change_ack ? 0x80 : 0);
85 buf[5] = bpdu->root.prio[0];
86 buf[6] = bpdu->root.prio[1];
87 buf[7] = bpdu->root.addr[0];
88 buf[8] = bpdu->root.addr[1];
89 buf[9] = bpdu->root.addr[2];
90 buf[10] = bpdu->root.addr[3];
91 buf[11] = bpdu->root.addr[4];
92 buf[12] = bpdu->root.addr[5];
93 buf[13] = (bpdu->root_path_cost >> 24) & 0xFF;
94 buf[14] = (bpdu->root_path_cost >> 16) & 0xFF;
95 buf[15] = (bpdu->root_path_cost >> 8) & 0xFF;
96 buf[16] = bpdu->root_path_cost & 0xFF;
97 buf[17] = bpdu->bridge_id.prio[0];
98 buf[18] = bpdu->bridge_id.prio[1];
99 buf[19] = bpdu->bridge_id.addr[0];
100 buf[20] = bpdu->bridge_id.addr[1];
101 buf[21] = bpdu->bridge_id.addr[2];
102 buf[22] = bpdu->bridge_id.addr[3];
103 buf[23] = bpdu->bridge_id.addr[4];
104 buf[24] = bpdu->bridge_id.addr[5];
105 buf[25] = (bpdu->port_id >> 8) & 0xFF;
106 buf[26] = bpdu->port_id & 0xFF;
107
108 br_set_ticks(buf+27, bpdu->message_age);
109 br_set_ticks(buf+29, bpdu->max_age);
110 br_set_ticks(buf+31, bpdu->hello_time);
111 br_set_ticks(buf+33, bpdu->forward_delay);
112
113 br_send_bpdu(p, buf, 35);
114}
115
116
117void br_send_tcn_bpdu(struct net_bridge_port *p)
118{
119 unsigned char buf[4];
120
121 if (p->br->stp_enabled != BR_KERNEL_STP)
122 return;
123
124 buf[0] = 0;
125 buf[1] = 0;
126 buf[2] = 0;
127 buf[3] = BPDU_TYPE_TCN;
128 br_send_bpdu(p, buf, 4);
129}
130
131
132
133
134
135
136int br_stp_rcv(struct sk_buff *skb, struct net_device *dev,
137 struct packet_type *pt, struct net_device *orig_dev)
138{
139 const struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb);
140 const unsigned char *dest = eth_hdr(skb)->h_dest;
141 struct net_bridge_port *p = rcu_dereference(dev->br_port);
142 struct net_bridge *br;
143 const unsigned char *buf;
144
145 if (dev->nd_net != &init_net)
146 goto err;
147
148 if (!p)
149 goto err;
150
151 if (pdu->ssap != LLC_SAP_BSPAN
152 || pdu->dsap != LLC_SAP_BSPAN
153 || pdu->ctrl_1 != LLC_PDU_TYPE_U)
154 goto err;
155
156 if (!pskb_may_pull(skb, 4))
157 goto err;
158
159
160 buf = skb->data;
161 if (buf[0] != 0 || buf[1] != 0 || buf[2] != 0)
162 goto err;
163
164 br = p->br;
165 spin_lock(&br->lock);
166
167 if (br->stp_enabled != BR_KERNEL_STP)
168 goto out;
169
170 if (!(br->dev->flags & IFF_UP))
171 goto out;
172
173 if (p->state == BR_STATE_DISABLED)
174 goto out;
175
176 if (compare_ether_addr(dest, br->group_addr) != 0)
177 goto out;
178
179 buf = skb_pull(skb, 3);
180
181 if (buf[0] == BPDU_TYPE_CONFIG) {
182 struct br_config_bpdu bpdu;
183
184 if (!pskb_may_pull(skb, 32))
185 goto out;
186
187 buf = skb->data;
188 bpdu.topology_change = (buf[1] & 0x01) ? 1 : 0;
189 bpdu.topology_change_ack = (buf[1] & 0x80) ? 1 : 0;
190
191 bpdu.root.prio[0] = buf[2];
192 bpdu.root.prio[1] = buf[3];
193 bpdu.root.addr[0] = buf[4];
194 bpdu.root.addr[1] = buf[5];
195 bpdu.root.addr[2] = buf[6];
196 bpdu.root.addr[3] = buf[7];
197 bpdu.root.addr[4] = buf[8];
198 bpdu.root.addr[5] = buf[9];
199 bpdu.root_path_cost =
200 (buf[10] << 24) |
201 (buf[11] << 16) |
202 (buf[12] << 8) |
203 buf[13];
204 bpdu.bridge_id.prio[0] = buf[14];
205 bpdu.bridge_id.prio[1] = buf[15];
206 bpdu.bridge_id.addr[0] = buf[16];
207 bpdu.bridge_id.addr[1] = buf[17];
208 bpdu.bridge_id.addr[2] = buf[18];
209 bpdu.bridge_id.addr[3] = buf[19];
210 bpdu.bridge_id.addr[4] = buf[20];
211 bpdu.bridge_id.addr[5] = buf[21];
212 bpdu.port_id = (buf[22] << 8) | buf[23];
213
214 bpdu.message_age = br_get_ticks(buf+24);
215 bpdu.max_age = br_get_ticks(buf+26);
216 bpdu.hello_time = br_get_ticks(buf+28);
217 bpdu.forward_delay = br_get_ticks(buf+30);
218
219 br_received_config_bpdu(p, &bpdu);
220 }
221
222 else if (buf[0] == BPDU_TYPE_TCN) {
223 br_received_tcn_bpdu(p);
224 }
225 out:
226 spin_unlock(&br->lock);
227 err:
228 kfree_skb(skb);
229 return 0;
230}
231
