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 | * | |
8 | * $Id: br_stp_bpdu.c,v 1.3 2001/11/10 02:35:25 davem Exp $ | |
9 | * | |
10 | * This program is free software; you can redistribute it and/or | |
11 | * modify it under the terms of the GNU General Public License | |
12 | * as published by the Free Software Foundation; either version | |
13 | * 2 of the License, or (at your option) any later version. | |
14 | */ | |
15 | ||
16 | #include <linux/kernel.h> | |
17 | #include <linux/netfilter_bridge.h> | |
cf0f02d0 SH |
18 | #include <linux/etherdevice.h> |
19 | #include <linux/llc.h> | |
12ac84c4 | 20 | #include <net/llc.h> |
cf0f02d0 | 21 | #include <net/llc_pdu.h> |
4dc6d9cc | 22 | #include <asm/unaligned.h> |
1da177e4 LT |
23 | |
24 | #include "br_private.h" | |
25 | #include "br_private_stp.h" | |
26 | ||
18fdb2b2 | 27 | #define STP_HZ 256 |
1da177e4 | 28 | |
12ac84c4 SH |
29 | #define LLC_RESERVE sizeof(struct llc_pdu_un) |
30 | ||
31 | static void br_send_bpdu(struct net_bridge_port *p, | |
32 | const unsigned char *data, int length) | |
1da177e4 | 33 | { |
1da177e4 | 34 | struct sk_buff *skb; |
1da177e4 LT |
35 | |
36 | if (!p->br->stp_enabled) | |
37 | return; | |
38 | ||
12ac84c4 SH |
39 | skb = dev_alloc_skb(length+LLC_RESERVE); |
40 | if (!skb) | |
1da177e4 | 41 | return; |
1da177e4 | 42 | |
12ac84c4 | 43 | skb->dev = p->dev; |
1da177e4 | 44 | skb->protocol = htons(ETH_P_802_2); |
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 LT |
54 | |
55 | NF_HOOK(PF_BRIDGE, NF_BR_LOCAL_OUT, skb, NULL, skb->dev, | |
56 | dev_queue_xmit); | |
57 | } | |
58 | ||
18fdb2b2 | 59 | static inline void br_set_ticks(unsigned char *dest, int j) |
1da177e4 | 60 | { |
18fdb2b2 | 61 | unsigned long ticks = (STP_HZ * j)/ HZ; |
1da177e4 | 62 | |
4dc6d9cc | 63 | put_unaligned(htons(ticks), (__be16 *)dest); |
1da177e4 LT |
64 | } |
65 | ||
18fdb2b2 | 66 | static inline int br_get_ticks(const unsigned char *src) |
1da177e4 | 67 | { |
4dc6d9cc | 68 | unsigned long ticks = ntohs(get_unaligned((__be16 *)src)); |
18fdb2b2 SH |
69 | |
70 | return (ticks * HZ + STP_HZ - 1) / STP_HZ; | |
1da177e4 LT |
71 | } |
72 | ||
73 | /* called under bridge lock */ | |
74 | void br_send_config_bpdu(struct net_bridge_port *p, struct br_config_bpdu *bpdu) | |
75 | { | |
12ac84c4 SH |
76 | unsigned char buf[35]; |
77 | ||
78 | buf[0] = 0; | |
79 | buf[1] = 0; | |
80 | buf[2] = 0; | |
81 | buf[3] = BPDU_TYPE_CONFIG; | |
82 | buf[4] = (bpdu->topology_change ? 0x01 : 0) | | |
1da177e4 | 83 | (bpdu->topology_change_ack ? 0x80 : 0); |
12ac84c4 SH |
84 | buf[5] = bpdu->root.prio[0]; |
85 | buf[6] = bpdu->root.prio[1]; | |
86 | buf[7] = bpdu->root.addr[0]; | |
87 | buf[8] = bpdu->root.addr[1]; | |
88 | buf[9] = bpdu->root.addr[2]; | |
89 | buf[10] = bpdu->root.addr[3]; | |
90 | buf[11] = bpdu->root.addr[4]; | |
91 | buf[12] = bpdu->root.addr[5]; | |
92 | buf[13] = (bpdu->root_path_cost >> 24) & 0xFF; | |
93 | buf[14] = (bpdu->root_path_cost >> 16) & 0xFF; | |
94 | buf[15] = (bpdu->root_path_cost >> 8) & 0xFF; | |
95 | buf[16] = bpdu->root_path_cost & 0xFF; | |
96 | buf[17] = bpdu->bridge_id.prio[0]; | |
97 | buf[18] = bpdu->bridge_id.prio[1]; | |
98 | buf[19] = bpdu->bridge_id.addr[0]; | |
99 | buf[20] = bpdu->bridge_id.addr[1]; | |
100 | buf[21] = bpdu->bridge_id.addr[2]; | |
101 | buf[22] = bpdu->bridge_id.addr[3]; | |
102 | buf[23] = bpdu->bridge_id.addr[4]; | |
103 | buf[24] = bpdu->bridge_id.addr[5]; | |
104 | buf[25] = (bpdu->port_id >> 8) & 0xFF; | |
105 | buf[26] = bpdu->port_id & 0xFF; | |
106 | ||
107 | br_set_ticks(buf+27, bpdu->message_age); | |
108 | br_set_ticks(buf+29, bpdu->max_age); | |
109 | br_set_ticks(buf+31, bpdu->hello_time); | |
110 | br_set_ticks(buf+33, bpdu->forward_delay); | |
111 | ||
112 | br_send_bpdu(p, buf, 35); | |
1da177e4 LT |
113 | } |
114 | ||
115 | /* called under bridge lock */ | |
116 | void br_send_tcn_bpdu(struct net_bridge_port *p) | |
117 | { | |
12ac84c4 SH |
118 | unsigned char buf[4]; |
119 | ||
120 | buf[0] = 0; | |
121 | buf[1] = 0; | |
122 | buf[2] = 0; | |
123 | buf[3] = BPDU_TYPE_TCN; | |
1da177e4 LT |
124 | br_send_bpdu(p, buf, 7); |
125 | } | |
126 | ||
cf0f02d0 SH |
127 | /* |
128 | * Called from llc. | |
129 | * | |
130 | * NO locks, but rcu_read_lock (preempt_disabled) | |
131 | */ | |
132 | int br_stp_rcv(struct sk_buff *skb, struct net_device *dev, | |
133 | struct packet_type *pt, struct net_device *orig_dev) | |
1da177e4 | 134 | { |
cf0f02d0 SH |
135 | const struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb); |
136 | const unsigned char *dest = eth_hdr(skb)->h_dest; | |
137 | struct net_bridge_port *p = rcu_dereference(dev->br_port); | |
b3f1be4b | 138 | struct net_bridge *br; |
cf0f02d0 | 139 | const unsigned char *buf; |
1da177e4 | 140 | |
b3f1be4b SH |
141 | if (!p) |
142 | goto err; | |
143 | ||
cf0f02d0 SH |
144 | if (pdu->ssap != LLC_SAP_BSPAN |
145 | || pdu->dsap != LLC_SAP_BSPAN | |
146 | || pdu->ctrl_1 != LLC_PDU_TYPE_U) | |
147 | goto err; | |
b3f1be4b | 148 | |
cf0f02d0 SH |
149 | if (!pskb_may_pull(skb, 4)) |
150 | goto err; | |
151 | ||
152 | /* compare of protocol id and version */ | |
153 | buf = skb->data; | |
154 | if (buf[0] != 0 || buf[1] != 0 || buf[2] != 0) | |
155 | goto err; | |
b3f1be4b | 156 | |
cf0f02d0 SH |
157 | br = p->br; |
158 | spin_lock(&br->lock); | |
b3f1be4b | 159 | |
cf0f02d0 SH |
160 | if (p->state == BR_STATE_DISABLED |
161 | || !br->stp_enabled | |
162 | || !(br->dev->flags & IFF_UP)) | |
b3f1be4b | 163 | goto out; |
85967bb4 | 164 | |
fda93d92 | 165 | if (compare_ether_addr(dest, br->group_addr) != 0) |
b3f1be4b | 166 | goto out; |
1da177e4 | 167 | |
cf0f02d0 | 168 | buf = skb_pull(skb, 3); |
1da177e4 | 169 | |
1da177e4 LT |
170 | if (buf[0] == BPDU_TYPE_CONFIG) { |
171 | struct br_config_bpdu bpdu; | |
172 | ||
173 | if (!pskb_may_pull(skb, 32)) | |
cf0f02d0 | 174 | goto out; |
1da177e4 LT |
175 | |
176 | buf = skb->data; | |
177 | bpdu.topology_change = (buf[1] & 0x01) ? 1 : 0; | |
178 | bpdu.topology_change_ack = (buf[1] & 0x80) ? 1 : 0; | |
179 | ||
180 | bpdu.root.prio[0] = buf[2]; | |
181 | bpdu.root.prio[1] = buf[3]; | |
182 | bpdu.root.addr[0] = buf[4]; | |
183 | bpdu.root.addr[1] = buf[5]; | |
184 | bpdu.root.addr[2] = buf[6]; | |
185 | bpdu.root.addr[3] = buf[7]; | |
186 | bpdu.root.addr[4] = buf[8]; | |
187 | bpdu.root.addr[5] = buf[9]; | |
188 | bpdu.root_path_cost = | |
189 | (buf[10] << 24) | | |
190 | (buf[11] << 16) | | |
191 | (buf[12] << 8) | | |
192 | buf[13]; | |
193 | bpdu.bridge_id.prio[0] = buf[14]; | |
194 | bpdu.bridge_id.prio[1] = buf[15]; | |
195 | bpdu.bridge_id.addr[0] = buf[16]; | |
196 | bpdu.bridge_id.addr[1] = buf[17]; | |
197 | bpdu.bridge_id.addr[2] = buf[18]; | |
198 | bpdu.bridge_id.addr[3] = buf[19]; | |
199 | bpdu.bridge_id.addr[4] = buf[20]; | |
200 | bpdu.bridge_id.addr[5] = buf[21]; | |
201 | bpdu.port_id = (buf[22] << 8) | buf[23]; | |
202 | ||
203 | bpdu.message_age = br_get_ticks(buf+24); | |
204 | bpdu.max_age = br_get_ticks(buf+26); | |
205 | bpdu.hello_time = br_get_ticks(buf+28); | |
206 | bpdu.forward_delay = br_get_ticks(buf+30); | |
207 | ||
208 | br_received_config_bpdu(p, &bpdu); | |
209 | } | |
210 | ||
211 | else if (buf[0] == BPDU_TYPE_TCN) { | |
212 | br_received_tcn_bpdu(p); | |
213 | } | |
214 | out: | |
b3f1be4b | 215 | spin_unlock(&br->lock); |
1da177e4 LT |
216 | err: |
217 | kfree_skb(skb); | |
218 | return 0; | |
219 | } |