1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
|
/*
* Copyright (c) 2011-2016 Cisco and/or its affiliates.
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at:
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
/**
* @file
* @brief LLDP packet parsing implementation
*/
#include <vnet/lldp/lldp_node.h>
#include <vnet/lldp/lldp_protocol.h>
lldp_tlv_code_t
lldp_tlv_get_code (const lldp_tlv_t * tlv)
{
return tlv->head.byte1 >> 1;
}
void
lldp_tlv_set_code (lldp_tlv_t * tlv, lldp_tlv_code_t code)
{
tlv->head.byte1 = (tlv->head.byte1 & 1) + (code << 1);
}
u16
lldp_tlv_get_length (const lldp_tlv_t * tlv)
{
return (((u16) (tlv->head.byte1 & 1)) << 8) + tlv->head.byte2;
}
void
lldp_tlv_set_length (lldp_tlv_t * tlv, u16 length)
{
tlv->head.byte2 = length & ((1 << 8) - 1);
if (length > (1 << 8) - 1)
{
tlv->head.byte1 |= 1;
}
else
{
tlv->head.byte1 &= (1 << 8) - 2;
}
}
lldp_main_t lldp_main;
static int
lldp_packet_scan (lldp_main_t * lm, lldp_intf_t * n, const lldp_tlv_t * pkt)
{
const lldp_tlv_t *tlv = pkt;
/* first check if the header fits in before extracting data from it */
#define TLV_VIOLATES_PKT_BOUNDARY(pkt, tlv) \
(((((u8 *)tlv) + sizeof(lldp_tlv_t)) > ((u8 *)pkt + vec_len(pkt))) || \
((((u8 *)tlv) + lldp_tlv_get_length(tlv)) > ((u8 *)pkt + vec_len(pkt))))
/* first tlv is always chassis id, followed by port id and ttl tlvs */
if (TLV_VIOLATES_PKT_BOUNDARY (pkt, tlv) ||
LLDP_TLV_NAME (chassis_id) != lldp_tlv_get_code (tlv))
{
return LLDP_ERROR_BAD_TLV;
}
u16 l = lldp_tlv_get_length (tlv);
if (l < STRUCT_SIZE_OF (lldp_chassis_id_tlv_t, subtype) +
LLDP_MIN_CHASS_ID_LEN ||
l > STRUCT_SIZE_OF (lldp_chassis_id_tlv_t, subtype) +
LLDP_MAX_CHASS_ID_LEN)
{
return LLDP_ERROR_BAD_TLV;
}
u8 chid_subtype = ((lldp_chassis_id_tlv_t *) tlv)->subtype;
u8 *chid = ((lldp_chassis_id_tlv_t *) tlv)->id;
u8 chid_len = l - STRUCT_SIZE_OF (lldp_chassis_id_tlv_t, subtype);
tlv = (lldp_tlv_t *) ((u8 *) tlv + STRUCT_SIZE_OF (lldp_tlv_t, head) + l);
if (TLV_VIOLATES_PKT_BOUNDARY (pkt, tlv) ||
LLDP_TLV_NAME (port_id) != lldp_tlv_get_code (tlv))
{
return LLDP_ERROR_BAD_TLV;
}
l = lldp_tlv_get_length (tlv);
if (l < STRUCT_SIZE_OF (lldp_port_id_tlv_t, subtype) +
LLDP_MIN_PORT_ID_LEN ||
l > STRUCT_SIZE_OF (lldp_chassis_id_tlv_t, subtype) +
LLDP_MAX_PORT_ID_LEN)
{
return LLDP_ERROR_BAD_TLV;
}
u8 portid_subtype = ((lldp_port_id_tlv_t *) tlv)->subtype;
u8 *portid = ((lldp_port_id_tlv_t *) tlv)->id;
u8 portid_len = l - STRUCT_SIZE_OF (lldp_port_id_tlv_t, subtype);
tlv = (lldp_tlv_t *) ((u8 *) tlv + STRUCT_SIZE_OF (lldp_tlv_t, head) + l);
if (TLV_VIOLATES_PKT_BOUNDARY (pkt, tlv) ||
LLDP_TLV_NAME (ttl) != lldp_tlv_get_code (tlv))
{
return LLDP_ERROR_BAD_TLV;
}
l = lldp_tlv_get_length (tlv);
if (l != STRUCT_SIZE_OF (lldp_ttl_tlv_t, ttl))
{
return LLDP_ERROR_BAD_TLV;
}
u16 ttl = ntohs (((lldp_ttl_tlv_t *) tlv)->ttl);
tlv = (lldp_tlv_t *) ((u8 *) tlv + STRUCT_SIZE_OF (lldp_tlv_t, head) + l);
while (!TLV_VIOLATES_PKT_BOUNDARY (pkt, tlv) &&
LLDP_TLV_NAME (pdu_end) != lldp_tlv_get_code (tlv))
{
switch (lldp_tlv_get_code (tlv))
{
#define F(num, type, str) \
case LLDP_TLV_NAME(type): \
/* ignore optional TLV */ \
break;
foreach_lldp_optional_tlv_type (F);
#undef F
default:
return LLDP_ERROR_BAD_TLV;
}
tlv = (lldp_tlv_t *) ((u8 *) tlv + STRUCT_SIZE_OF (lldp_tlv_t, head) +
lldp_tlv_get_length (tlv));
}
/* last tlv is pdu_end */
if (TLV_VIOLATES_PKT_BOUNDARY (pkt, tlv) ||
LLDP_TLV_NAME (pdu_end) != lldp_tlv_get_code (tlv) ||
0 != lldp_tlv_get_length (tlv))
{
return LLDP_ERROR_BAD_TLV;
}
/* LLDP PDU validated, now store data */
if (n->chassis_id)
{
_vec_len (n->chassis_id) = 0;
}
vec_add (n->chassis_id, chid, chid_len);
n->chassis_id_subtype = chid_subtype;
if (n->port_id)
{
_vec_len (n->port_id) = 0;
}
vec_add (n->port_id, portid, portid_len);
n->port_id_subtype = portid_subtype;
n->ttl = ttl;
return LLDP_ERROR_NONE;
}
lldp_intf_t *
lldp_get_intf (lldp_main_t * lm, u32 hw_if_index)
{
uword *p = hash_get (lm->intf_by_hw_if_index, hw_if_index);
if (p)
{
return pool_elt_at_index (lm->intfs, p[0]);
}
return NULL;
}
lldp_intf_t *
lldp_create_intf (lldp_main_t * lm, u32 hw_if_index)
{
uword *p;
lldp_intf_t *n;
p = hash_get (lm->intf_by_hw_if_index, hw_if_index);
if (p == 0)
{
pool_get (lm->intfs, n);
memset (n, 0, sizeof (*n));
n->hw_if_index = hw_if_index;
hash_set (lm->intf_by_hw_if_index, n->hw_if_index, n - lm->intfs);
}
else
{
n = pool_elt_at_index (lm->intfs, p[0]);
}
return n;
}
/*
* lldp input routine
*/
lldp_error_t
lldp_input (vlib_main_t * vm, vlib_buffer_t * b0, u32 bi0)
{
lldp_main_t *lm = &lldp_main;
lldp_error_t e;
/* find our interface */
lldp_intf_t *n = lldp_get_intf (lm, vnet_buffer (b0)->sw_if_index[VLIB_RX]);
if (!n)
{
/* lldp disabled on this interface, we're done */
return LLDP_ERROR_DISABLED;
}
/* Actually scan the packet */
e = lldp_packet_scan (lm, n, vlib_buffer_get_current (b0));
if (LLDP_ERROR_NONE == e)
{
n->last_heard = vlib_time_now (vm);
}
return e;
}
/*
* setup function
*/
static clib_error_t *
lldp_init (vlib_main_t * vm)
{
clib_error_t *error;
lldp_main_t *lm = &lldp_main;
if ((error = vlib_call_init_function (vm, lldp_template_init)))
return error;
lm->vlib_main = vm;
lm->vnet_main = vnet_get_main ();
lm->msg_tx_hold = 4; /* default value per IEEE 802.1AB-2009 */
lm->msg_tx_interval = 30; /* default value per IEEE 802.1AB-2009 */
return 0;
}
VLIB_INIT_FUNCTION (lldp_init);
/*
* fd.io coding-style-patch-verification: ON
*
* Local Variables:
* eval: (c-set-style "gnu")
* End:
*/
|
