Merge git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6
[firefly-linux-kernel-4.4.55.git] / net / bridge / br_stp_bpdu.c
1 /*
2  *      Spanning tree protocol; BPDU handling
3  *      Linux ethernet bridge
4  *
5  *      Authors:
6  *      Lennert Buytenhek               <buytenh@gnu.org>
7  *
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>
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
33 static 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
61 static 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
68 static 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 /* called under bridge lock */
76 void 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 /* called under bridge lock */
121 void 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  * Called from llc.
137  *
138  * NO locks, but rcu_read_lock
139  */
140 void 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         /* compare of protocol id and version */
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 }