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> | |
e730c155 | 18 | #include <net/net_namespace.h> |
12ac84c4 | 19 | #include <net/llc.h> |
cf0f02d0 | 20 | #include <net/llc_pdu.h> |
4dc6d9cc | 21 | #include <asm/unaligned.h> |
1da177e4 LT |
22 | |
23 | #include "br_private.h" | |
24 | #include "br_private_stp.h" | |
25 | ||
18fdb2b2 | 26 | #define STP_HZ 256 |
1da177e4 | 27 | |
12ac84c4 SH |
28 | #define LLC_RESERVE sizeof(struct llc_pdu_un) |
29 | ||
30 | static void br_send_bpdu(struct net_bridge_port *p, | |
9d6f229f | 31 | const unsigned char *data, int length) |
1da177e4 | 32 | { |
1da177e4 | 33 | struct sk_buff *skb; |
1da177e4 | 34 | |
12ac84c4 SH |
35 | skb = dev_alloc_skb(length+LLC_RESERVE); |
36 | if (!skb) | |
1da177e4 | 37 | return; |
1da177e4 | 38 | |
12ac84c4 | 39 | skb->dev = p->dev; |
1da177e4 | 40 | skb->protocol = htons(ETH_P_802_2); |
12ac84c4 SH |
41 | |
42 | skb_reserve(skb, LLC_RESERVE); | |
43 | memcpy(__skb_put(skb, length), data, length); | |
44 | ||
45 | llc_pdu_header_init(skb, LLC_PDU_TYPE_U, LLC_SAP_BSPAN, | |
46 | LLC_SAP_BSPAN, LLC_PDU_CMD); | |
47 | llc_pdu_init_as_ui_cmd(skb); | |
48 | ||
49 | llc_mac_hdr_init(skb, p->dev->dev_addr, p->br->group_addr); | |
1da177e4 LT |
50 | |
51 | NF_HOOK(PF_BRIDGE, NF_BR_LOCAL_OUT, skb, NULL, skb->dev, | |
52 | dev_queue_xmit); | |
53 | } | |
54 | ||
18fdb2b2 | 55 | static inline void br_set_ticks(unsigned char *dest, int j) |
1da177e4 | 56 | { |
18fdb2b2 | 57 | unsigned long ticks = (STP_HZ * j)/ HZ; |
1da177e4 | 58 | |
d3e2ce3b | 59 | put_unaligned_be16(ticks, dest); |
1da177e4 LT |
60 | } |
61 | ||
18fdb2b2 | 62 | static inline int br_get_ticks(const unsigned char *src) |
1da177e4 | 63 | { |
d3e2ce3b | 64 | unsigned long ticks = get_unaligned_be16(src); |
18fdb2b2 | 65 | |
172589cc | 66 | return DIV_ROUND_UP(ticks * HZ, STP_HZ); |
1da177e4 LT |
67 | } |
68 | ||
69 | /* called under bridge lock */ | |
70 | void br_send_config_bpdu(struct net_bridge_port *p, struct br_config_bpdu *bpdu) | |
71 | { | |
12ac84c4 SH |
72 | unsigned char buf[35]; |
73 | ||
9cde0708 SH |
74 | if (p->br->stp_enabled != BR_KERNEL_STP) |
75 | return; | |
76 | ||
12ac84c4 SH |
77 | buf[0] = 0; |
78 | buf[1] = 0; | |
79 | buf[2] = 0; | |
80 | buf[3] = BPDU_TYPE_CONFIG; | |
81 | buf[4] = (bpdu->topology_change ? 0x01 : 0) | | |
1da177e4 | 82 | (bpdu->topology_change_ack ? 0x80 : 0); |
12ac84c4 SH |
83 | buf[5] = bpdu->root.prio[0]; |
84 | buf[6] = bpdu->root.prio[1]; | |
85 | buf[7] = bpdu->root.addr[0]; | |
86 | buf[8] = bpdu->root.addr[1]; | |
87 | buf[9] = bpdu->root.addr[2]; | |
88 | buf[10] = bpdu->root.addr[3]; | |
89 | buf[11] = bpdu->root.addr[4]; | |
90 | buf[12] = bpdu->root.addr[5]; | |
91 | buf[13] = (bpdu->root_path_cost >> 24) & 0xFF; | |
92 | buf[14] = (bpdu->root_path_cost >> 16) & 0xFF; | |
93 | buf[15] = (bpdu->root_path_cost >> 8) & 0xFF; | |
94 | buf[16] = bpdu->root_path_cost & 0xFF; | |
95 | buf[17] = bpdu->bridge_id.prio[0]; | |
96 | buf[18] = bpdu->bridge_id.prio[1]; | |
97 | buf[19] = bpdu->bridge_id.addr[0]; | |
98 | buf[20] = bpdu->bridge_id.addr[1]; | |
99 | buf[21] = bpdu->bridge_id.addr[2]; | |
100 | buf[22] = bpdu->bridge_id.addr[3]; | |
101 | buf[23] = bpdu->bridge_id.addr[4]; | |
102 | buf[24] = bpdu->bridge_id.addr[5]; | |
103 | buf[25] = (bpdu->port_id >> 8) & 0xFF; | |
104 | buf[26] = bpdu->port_id & 0xFF; | |
105 | ||
106 | br_set_ticks(buf+27, bpdu->message_age); | |
107 | br_set_ticks(buf+29, bpdu->max_age); | |
108 | br_set_ticks(buf+31, bpdu->hello_time); | |
109 | br_set_ticks(buf+33, bpdu->forward_delay); | |
110 | ||
111 | br_send_bpdu(p, buf, 35); | |
1da177e4 LT |
112 | } |
113 | ||
114 | /* called under bridge lock */ | |
115 | void br_send_tcn_bpdu(struct net_bridge_port *p) | |
116 | { | |
12ac84c4 SH |
117 | unsigned char buf[4]; |
118 | ||
9cde0708 SH |
119 | if (p->br->stp_enabled != BR_KERNEL_STP) |
120 | return; | |
121 | ||
12ac84c4 SH |
122 | buf[0] = 0; |
123 | buf[1] = 0; | |
124 | buf[2] = 0; | |
125 | buf[3] = BPDU_TYPE_TCN; | |
485c2967 | 126 | br_send_bpdu(p, buf, 4); |
1da177e4 LT |
127 | } |
128 | ||
cf0f02d0 SH |
129 | /* |
130 | * Called from llc. | |
131 | * | |
132 | * NO locks, but rcu_read_lock (preempt_disabled) | |
133 | */ | |
134 | int br_stp_rcv(struct sk_buff *skb, struct net_device *dev, | |
135 | struct packet_type *pt, struct net_device *orig_dev) | |
1da177e4 | 136 | { |
cf0f02d0 SH |
137 | const struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb); |
138 | const unsigned char *dest = eth_hdr(skb)->h_dest; | |
139 | struct net_bridge_port *p = rcu_dereference(dev->br_port); | |
b3f1be4b | 140 | struct net_bridge *br; |
cf0f02d0 | 141 | const unsigned char *buf; |
1da177e4 | 142 | |
c346dca1 | 143 | if (dev_net(dev) != &init_net) |
e730c155 EB |
144 | goto err; |
145 | ||
b3f1be4b SH |
146 | if (!p) |
147 | goto err; | |
148 | ||
cf0f02d0 SH |
149 | if (pdu->ssap != LLC_SAP_BSPAN |
150 | || pdu->dsap != LLC_SAP_BSPAN | |
151 | || pdu->ctrl_1 != LLC_PDU_TYPE_U) | |
152 | goto err; | |
b3f1be4b | 153 | |
cf0f02d0 SH |
154 | if (!pskb_may_pull(skb, 4)) |
155 | goto err; | |
156 | ||
157 | /* compare of protocol id and version */ | |
158 | buf = skb->data; | |
159 | if (buf[0] != 0 || buf[1] != 0 || buf[2] != 0) | |
160 | goto err; | |
b3f1be4b | 161 | |
cf0f02d0 SH |
162 | br = p->br; |
163 | spin_lock(&br->lock); | |
b3f1be4b | 164 | |
9cde0708 SH |
165 | if (br->stp_enabled != BR_KERNEL_STP) |
166 | goto out; | |
167 | ||
168 | if (!(br->dev->flags & IFF_UP)) | |
169 | goto out; | |
170 | ||
171 | if (p->state == BR_STATE_DISABLED) | |
b3f1be4b | 172 | goto out; |
85967bb4 | 173 | |
fda93d92 | 174 | if (compare_ether_addr(dest, br->group_addr) != 0) |
b3f1be4b | 175 | goto out; |
1da177e4 | 176 | |
cf0f02d0 | 177 | buf = skb_pull(skb, 3); |
1da177e4 | 178 | |
1da177e4 LT |
179 | if (buf[0] == BPDU_TYPE_CONFIG) { |
180 | struct br_config_bpdu bpdu; | |
181 | ||
182 | if (!pskb_may_pull(skb, 32)) | |
cf0f02d0 | 183 | goto out; |
1da177e4 LT |
184 | |
185 | buf = skb->data; | |
186 | bpdu.topology_change = (buf[1] & 0x01) ? 1 : 0; | |
187 | bpdu.topology_change_ack = (buf[1] & 0x80) ? 1 : 0; | |
188 | ||
189 | bpdu.root.prio[0] = buf[2]; | |
190 | bpdu.root.prio[1] = buf[3]; | |
191 | bpdu.root.addr[0] = buf[4]; | |
192 | bpdu.root.addr[1] = buf[5]; | |
193 | bpdu.root.addr[2] = buf[6]; | |
194 | bpdu.root.addr[3] = buf[7]; | |
195 | bpdu.root.addr[4] = buf[8]; | |
196 | bpdu.root.addr[5] = buf[9]; | |
197 | bpdu.root_path_cost = | |
198 | (buf[10] << 24) | | |
199 | (buf[11] << 16) | | |
200 | (buf[12] << 8) | | |
201 | buf[13]; | |
202 | bpdu.bridge_id.prio[0] = buf[14]; | |
203 | bpdu.bridge_id.prio[1] = buf[15]; | |
204 | bpdu.bridge_id.addr[0] = buf[16]; | |
205 | bpdu.bridge_id.addr[1] = buf[17]; | |
206 | bpdu.bridge_id.addr[2] = buf[18]; | |
207 | bpdu.bridge_id.addr[3] = buf[19]; | |
208 | bpdu.bridge_id.addr[4] = buf[20]; | |
209 | bpdu.bridge_id.addr[5] = buf[21]; | |
210 | bpdu.port_id = (buf[22] << 8) | buf[23]; | |
211 | ||
212 | bpdu.message_age = br_get_ticks(buf+24); | |
213 | bpdu.max_age = br_get_ticks(buf+26); | |
214 | bpdu.hello_time = br_get_ticks(buf+28); | |
215 | bpdu.forward_delay = br_get_ticks(buf+30); | |
216 | ||
217 | br_received_config_bpdu(p, &bpdu); | |
218 | } | |
219 | ||
220 | else if (buf[0] == BPDU_TYPE_TCN) { | |
221 | br_received_tcn_bpdu(p); | |
222 | } | |
223 | out: | |
b3f1be4b | 224 | spin_unlock(&br->lock); |
1da177e4 LT |
225 | err: |
226 | kfree_skb(skb); | |
227 | return 0; | |
228 | } |