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Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * Spanning tree protocol; BPDU handling | |
3 | * Linux ethernet bridge | |
4 | * | |
5 | * Authors: | |
6 | * Lennert Buytenhek <buytenh@gnu.org> | |
7 | * | |
1da177e4 LT |
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/netfilter_bridge.h> | |
cf0f02d0 SH |
16 | #include <linux/etherdevice.h> |
17 | #include <linux/llc.h> | |
5a0e3ad6 | 18 | #include <linux/slab.h> |
547b4e71 | 19 | #include <linux/pkt_sched.h> |
e730c155 | 20 | #include <net/net_namespace.h> |
12ac84c4 | 21 | #include <net/llc.h> |
cf0f02d0 | 22 | #include <net/llc_pdu.h> |
7c85fbf0 | 23 | #include <net/stp.h> |
4dc6d9cc | 24 | #include <asm/unaligned.h> |
1da177e4 LT |
25 | |
26 | #include "br_private.h" | |
27 | #include "br_private_stp.h" | |
28 | ||
18fdb2b2 | 29 | #define STP_HZ 256 |
1da177e4 | 30 | |
12ac84c4 SH |
31 | #define LLC_RESERVE sizeof(struct llc_pdu_un) |
32 | ||
33 | static void br_send_bpdu(struct net_bridge_port *p, | |
9d6f229f | 34 | const unsigned char *data, int length) |
1da177e4 | 35 | { |
1da177e4 | 36 | struct sk_buff *skb; |
1da177e4 | 37 | |
12ac84c4 SH |
38 | skb = dev_alloc_skb(length+LLC_RESERVE); |
39 | if (!skb) | |
1da177e4 | 40 | return; |
1da177e4 | 41 | |
12ac84c4 | 42 | skb->dev = p->dev; |
1da177e4 | 43 | skb->protocol = htons(ETH_P_802_2); |
547b4e71 | 44 | skb->priority = TC_PRIO_CONTROL; |
12ac84c4 SH |
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); | |
1da177e4 | 54 | |
e6f26129 FW |
55 | skb_reset_mac_header(skb); |
56 | ||
713aefa3 | 57 | NF_HOOK(NFPROTO_BRIDGE, NF_BR_LOCAL_OUT, skb, NULL, skb->dev, |
1da177e4 LT |
58 | dev_queue_xmit); |
59 | } | |
60 | ||
18fdb2b2 | 61 | static inline void br_set_ticks(unsigned char *dest, int j) |
1da177e4 | 62 | { |
18fdb2b2 | 63 | unsigned long ticks = (STP_HZ * j)/ HZ; |
1da177e4 | 64 | |
d3e2ce3b | 65 | put_unaligned_be16(ticks, dest); |
1da177e4 LT |
66 | } |
67 | ||
18fdb2b2 | 68 | static inline int br_get_ticks(const unsigned char *src) |
1da177e4 | 69 | { |
d3e2ce3b | 70 | unsigned long ticks = get_unaligned_be16(src); |
18fdb2b2 | 71 | |
172589cc | 72 | return DIV_ROUND_UP(ticks * HZ, STP_HZ); |
1da177e4 LT |
73 | } |
74 | ||
75 | /* called under bridge lock */ | |
76 | void br_send_config_bpdu(struct net_bridge_port *p, struct br_config_bpdu *bpdu) | |
77 | { | |
12ac84c4 SH |
78 | unsigned char buf[35]; |
79 | ||
9cde0708 SH |
80 | if (p->br->stp_enabled != BR_KERNEL_STP) |
81 | return; | |
82 | ||
12ac84c4 SH |
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) | | |
1da177e4 | 88 | (bpdu->topology_change_ack ? 0x80 : 0); |
12ac84c4 SH |
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); | |
1da177e4 LT |
118 | } |
119 | ||
120 | /* called under bridge lock */ | |
121 | void br_send_tcn_bpdu(struct net_bridge_port *p) | |
122 | { | |
12ac84c4 SH |
123 | unsigned char buf[4]; |
124 | ||
9cde0708 SH |
125 | if (p->br->stp_enabled != BR_KERNEL_STP) |
126 | return; | |
127 | ||
12ac84c4 SH |
128 | buf[0] = 0; |
129 | buf[1] = 0; | |
130 | buf[2] = 0; | |
131 | buf[3] = BPDU_TYPE_TCN; | |
485c2967 | 132 | br_send_bpdu(p, buf, 4); |
1da177e4 LT |
133 | } |
134 | ||
cf0f02d0 SH |
135 | /* |
136 | * Called from llc. | |
137 | * | |
eeaf61d8 | 138 | * NO locks, but rcu_read_lock |
cf0f02d0 | 139 | */ |
7c85fbf0 PM |
140 | void br_stp_rcv(const struct stp_proto *proto, struct sk_buff *skb, |
141 | struct net_device *dev) | |
1da177e4 | 142 | { |
cf0f02d0 | 143 | const unsigned char *dest = eth_hdr(skb)->h_dest; |
f350a0a8 | 144 | struct net_bridge_port *p; |
b3f1be4b | 145 | struct net_bridge *br; |
cf0f02d0 | 146 | const unsigned char *buf; |
1da177e4 | 147 | |
cf0f02d0 SH |
148 | if (!pskb_may_pull(skb, 4)) |
149 | goto err; | |
150 | ||
151 | /* compare of protocol id and version */ | |
152 | buf = skb->data; | |
153 | if (buf[0] != 0 || buf[1] != 0 || buf[2] != 0) | |
154 | goto err; | |
b3f1be4b | 155 | |
b5ed54e9 | 156 | p = br_port_get_rcu(dev); |
157 | if (!p) | |
158 | goto err; | |
159 | ||
cf0f02d0 SH |
160 | br = p->br; |
161 | spin_lock(&br->lock); | |
b3f1be4b | 162 | |
9cde0708 SH |
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) | |
b3f1be4b | 170 | goto out; |
85967bb4 | 171 | |
9a7b6ef9 | 172 | if (!ether_addr_equal(dest, br->group_addr)) |
b3f1be4b | 173 | goto out; |
1da177e4 | 174 | |
a2e01a65 | 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 | ||
cf0f02d0 | 182 | buf = skb_pull(skb, 3); |
1da177e4 | 183 | |
1da177e4 LT |
184 | if (buf[0] == BPDU_TYPE_CONFIG) { |
185 | struct br_config_bpdu bpdu; | |
186 | ||
187 | if (!pskb_may_pull(skb, 32)) | |
cf0f02d0 | 188 | goto out; |
1da177e4 LT |
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 | ||
0652cac2 | 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 | ||
1da177e4 | 233 | br_received_config_bpdu(p, &bpdu); |
160d73b8 | 234 | } else if (buf[0] == BPDU_TYPE_TCN) { |
1da177e4 LT |
235 | br_received_tcn_bpdu(p); |
236 | } | |
237 | out: | |
b3f1be4b | 238 | spin_unlock(&br->lock); |
1da177e4 LT |
239 | err: |
240 | kfree_skb(skb); | |
1da177e4 | 241 | } |