FD.io VPP  v18.07.1-13-g909ba93
Vector Packet Processing
cdp_input.c
Go to the documentation of this file.
1 /*
2  * Copyright (c) 2011-2016 Cisco and/or its affiliates.
3  * Licensed under the Apache License, Version 2.0 (the "License");
4  * you may not use this file except in compliance with the License.
5  * You may obtain a copy of the License at:
6  *
7  * http://www.apache.org/licenses/LICENSE-2.0
8  *
9  * Unless required by applicable law or agreed to in writing, software
10  * distributed under the License is distributed on an "AS IS" BASIS,
11  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12  * See the License for the specific language governing permissions and
13  * limitations under the License.
14  */
15 #include <cdp/cdp.h>
16 
18 
19 #define DEBUG_TLV_DUMP 0 /* 1=> dump TLV's to stdout while processing them */
20 
21 /*
22  * ported from an unspecified Cisco cdp implementation.
23  * Compute / return in HOST byte order. 0 => good checksum.
24  */
25 u16
26 cdp_checksum (void *p, int count)
27 {
28  u32 sum;
29  u16 i, *data;
30 
31  data = p;
32  sum = 0;
33  while (count > 1)
34  {
35  sum += ntohs (*data);
36  data++;
37  count -= 2;
38  }
39 
40  if (count > 0)
41  sum += *(char *) data;
42 
43  while (sum >> 16)
44  {
45  sum = (sum & 0xFFFF) + (sum >> 16);
46  }
47 
48  i = (i16) sum;
49  return (~i);
50 }
51 
52 /* TLV handler table */
53 typedef struct
54 {
55  char *name;
57  void *format;
58  void *process;
60 
61 static tlv_handler_t tlv_handlers[];
62 
63 /* Display a generic TLV as a set of hex bytes */
64 static u8 *
65 format_generic_tlv (u8 * s, va_list * va)
66 {
67  cdp_tlv_t *t = va_arg (*va, cdp_tlv_t *);
68  tlv_handler_t *h = &tlv_handlers[t->t];
69 
70  s = format (s, "%s(%d): %U\n", h->name,
71  t->t, format_hex_bytes, t->v, t->l - sizeof (*t));
72  return s;
73 }
74 
75 /* Ignore / skip a TLV we don't support */
76 static cdp_error_t
77 process_generic_tlv (cdp_main_t * cm, cdp_neighbor_t * n, cdp_tlv_t * t)
78 {
79 #if DEBUG_TLV_DUMP > 0
80  fformat (stdout, "%U", format_generic_tlv, t);
81 #endif
82 
83  return CDP_ERROR_NONE;
84 }
85 
86 /* print a text tlv */
87 static u8 *
88 format_text_tlv (u8 * s, va_list * va)
89 {
90  cdp_tlv_t *t = va_arg (*va, cdp_tlv_t *);
91  tlv_handler_t *h = &tlv_handlers[t->t];
92  int i;
93 
94  s = format (s, "%s(%d): ", h->name, t->t);
95 
96  for (i = 0; i < (t->l - sizeof (*t)); i++)
97  vec_add1 (s, t->v[i]);
98 
99  vec_add1 (s, '\n');
100  return s;
101 }
102 
103 #if DEBUG_TLV_DUMP == 0
104 /* gcc warning be gone */
105 CLIB_UNUSED (static cdp_error_t
107  cdp_tlv_t * t));
108 #endif
109 
110 /* process / skip a generic text TLV that we don't support */
111 static cdp_error_t
112 process_text_tlv (cdp_main_t * cm, cdp_neighbor_t * n, cdp_tlv_t * t)
113 {
114 #if DEBUG_TLV_DUMP > 0
115  fformat (stdout, "%U\n", format_text_tlv, t);
116 #endif
117 
118  return CDP_ERROR_NONE;
119 }
120 
121 /* per-TLV format function definitions */
122 #define format_unused_tlv format_generic_tlv
123 #define format_device_name_tlv format_text_tlv
124 #define format_address_tlv format_generic_tlv
125 #define format_port_id_tlv format_text_tlv
126 #define format_capabilities_tlv format_generic_tlv
127 #define format_version_tlv format_text_tlv
128 #define format_platform_tlv format_text_tlv
129 #define format_ipprefix_tlv format_generic_tlv
130 #define format_hello_tlv format_generic_tlv
131 #define format_vtp_domain_tlv format_generic_tlv
132 #define format_native_vlan_tlv format_generic_tlv
133 #define format_duplex_tlv format_generic_tlv
134 #define format_appl_vlan_tlv format_generic_tlv
135 #define format_trigger_tlv format_generic_tlv
136 #define format_power_tlv format_generic_tlv
137 #define format_mtu_tlv format_generic_tlv
138 #define format_trust_tlv format_generic_tlv
139 #define format_cos_tlv format_generic_tlv
140 #define format_sysname_tlv format_generic_tlv
141 #define format_sysobject_tlv format_generic_tlv
142 #define format_mgmt_addr_tlv format_generic_tlv
143 #define format_physical_loc_tlv format_generic_tlv
144 #define format_mgmt_addr2_tlv format_generic_tlv
145 #define format_power_requested_tlv format_generic_tlv
146 #define format_power_available_tlv format_generic_tlv
147 #define format_port_unidirectional_tlv format_generic_tlv
148 #define format_unknown_28_tlv format_generic_tlv
149 #define format_energywise_tlv format_generic_tlv
150 #define format_unknown_30_tlv format_generic_tlv
151 #define format_spare_poe_tlv format_generic_tlv
152 
153 /* tlv ID=0 is a mistake */
154 static cdp_error_t
155 process_unused_tlv (cdp_main_t * cm, cdp_neighbor_t * n, cdp_tlv_t * t)
156 {
157  return CDP_ERROR_BAD_TLV;
158 }
159 
160 /* list of text TLV's that we snapshoot */
161 #define foreach_text_to_struct_tlv \
162 _(device_name,DEBUG_TLV_DUMP) \
163 _(version,DEBUG_TLV_DUMP) \
164 _(platform,DEBUG_TLV_DUMP) \
165 _(port_id,DEBUG_TLV_DUMP)
166 
167 #define _(z,dbg) \
168 static \
169 cdp_error_t process_##z##_tlv (cdp_main_t *cm, cdp_neighbor_t *n, \
170  cdp_tlv_t *t) \
171 { \
172  int i; \
173  if (dbg) \
174  fformat(stdout, "%U\n", format_text_tlv, t); \
175  \
176  if (n->z) \
177  _vec_len(n->z) = 0; \
178  \
179  for (i = 0; i < (t->l - sizeof (*t)); i++) \
180  vec_add1(n->z, t->v[i]); \
181  \
182  vec_add1(n->z, 0); \
183  \
184  return CDP_ERROR_NONE; \
185 }
186 
188 #undef _
189 #define process_address_tlv process_generic_tlv
190 #define process_capabilities_tlv process_generic_tlv
191 #define process_ipprefix_tlv process_generic_tlv
192 #define process_hello_tlv process_generic_tlv
193 #define process_vtp_domain_tlv process_generic_tlv
194 #define process_native_vlan_tlv process_generic_tlv
195 #define process_duplex_tlv process_generic_tlv
196 #define process_appl_vlan_tlv process_generic_tlv
197 #define process_trigger_tlv process_generic_tlv
198 #define process_power_tlv process_generic_tlv
199 #define process_mtu_tlv process_generic_tlv
200 #define process_trust_tlv process_generic_tlv
201 #define process_cos_tlv process_generic_tlv
202 #define process_sysname_tlv process_generic_tlv
203 #define process_sysobject_tlv process_generic_tlv
204 #define process_mgmt_addr_tlv process_generic_tlv
205 #define process_physical_loc_tlv process_generic_tlv
206 #define process_mgmt_addr2_tlv process_generic_tlv
207 #define process_power_requested_tlv process_generic_tlv
208 #define process_power_available_tlv process_generic_tlv
209 #define process_port_unidirectional_tlv process_generic_tlv
210 #define process_unknown_28_tlv process_generic_tlv
211 #define process_energywise_tlv process_generic_tlv
212 #define process_unknown_30_tlv process_generic_tlv
213 #define process_spare_poe_tlv process_generic_tlv
214 static tlv_handler_t tlv_handlers[] = {
215 #define _(a) {#a, CDP_TLV_##a, format_##a##_tlv, process_##a##_tlv},
217 #undef _
218 };
219 
220 #if DEBUG_TLV_DUMP == 0
221 CLIB_UNUSED (static u8 * format_cdp_hdr (u8 * s, va_list * va));
222 #endif
223 
224 static u8 *
225 format_cdp_hdr (u8 * s, va_list * va)
226 {
227  cdp_hdr_t *h = va_arg (*va, cdp_hdr_t *);
228 
229  s = format (s, "version %d, ttl %d(secs), cksum 0x%04x\n",
230  h->version, h->ttl, h->checksum);
231  return s;
232 }
233 
234 static cdp_error_t
235 process_cdp_hdr (cdp_main_t * cm, cdp_neighbor_t * n, cdp_hdr_t * h)
236 {
237 #if DEBUG_TLV_DUMP > 0
238  fformat (stdout, "%U", format_cdp_hdr, h);
239 #endif
240 
241  if (h->version != 1 && h->version != 2)
242  return CDP_ERROR_PROTOCOL_VERSION;
243 
244  n->ttl_in_seconds = h->ttl;
245 
246  return CDP_ERROR_NONE;
247 }
248 
249 /* scan a cdp packet; header, then tlv's */
250 static int
252 {
253  u8 *cur = n->last_rx_pkt;
254  cdp_hdr_t *h;
255  cdp_tlv_t *tlv;
256  cdp_error_t e = CDP_ERROR_NONE;
257  tlv_handler_t *handler;
258  cdp_error_t (*fp) (cdp_main_t *, cdp_neighbor_t *, cdp_tlv_t *);
259  u16 computed_checksum;
260 
261  computed_checksum = cdp_checksum (cur, vec_len (cur));
262 
263  if (computed_checksum)
264  return CDP_ERROR_CHECKSUM;
265 
266  h = (cdp_hdr_t *) cur;
267 
268  e = process_cdp_hdr (cm, n, h);
269  if (e)
270  return e;
271 
272  cur = (u8 *) (h + 1);
273 
274  while (cur < n->last_rx_pkt + vec_len (n->last_rx_pkt) - 1)
275  {
276  tlv = (cdp_tlv_t *) cur;
277  tlv->t = ntohs (tlv->t);
278  tlv->l = ntohs (tlv->l);
279  if (tlv->t >= ARRAY_LEN (tlv_handlers))
280  return CDP_ERROR_BAD_TLV;
281  handler = &tlv_handlers[tlv->t];
282  fp = handler->process;
283  e = (*fp) (cm, n, tlv);
284  if (e)
285  return e;
286  /* tlv length includes (t, l) */
287  cur += tlv->l;
288  }
289 
290  return CDP_ERROR_NONE;
291 }
292 
293 /*
294  * cdp input routine
295  */
298 {
299  cdp_main_t *cm = &cdp_main;
300  cdp_neighbor_t *n;
301  uword *p, nbytes;
302  cdp_error_t e;
303  uword last_packet_signature;
304 
305  /* find or create a neighbor pool entry for the (sw) interface
306  upon which we received this pkt */
308  vnet_buffer (b0)->sw_if_index[VLIB_RX]);
309 
310  if (p == 0)
311  {
312  pool_get (cm->neighbors, n);
313  memset (n, 0, sizeof (*n));
314  n->sw_if_index = vnet_buffer (b0)->sw_if_index[VLIB_RX];
315  n->packet_template_index = (u8) ~ 0;
317  n - cm->neighbors);
318  }
319  else
320  {
321  n = pool_elt_at_index (cm->neighbors, p[0]);
322  }
323 
324  /*
325  * typical clib idiom. Don't repeatedly allocate and free
326  * the per-neighbor rx buffer. Reset its apparent length to zero
327  * and reuse it.
328  */
329 
330  if (n->last_rx_pkt)
331  _vec_len (n->last_rx_pkt) = 0;
332 
333  /* cdp disabled on this interface, we're done */
334  if (n->disabled)
335  return CDP_ERROR_DISABLED;
336 
337  /*
338  * Make sure the per-neighbor rx buffer is big enough to hold
339  * the data we're about to copy
340  */
342 
343  /*
344  * Coalesce / copy e the buffer chain into the per-neighbor
345  * rx buffer
346  */
347  nbytes = vlib_buffer_contents (vm, bi0, n->last_rx_pkt);
348  ASSERT (nbytes <= vec_len (n->last_rx_pkt));
349 
350  /*
351  * Compute Jenkins hash of the new packet, decide if we need to
352  * actually parse through the TLV's. CDP packets are all identical,
353  * so unless we time out the peer, we don't need to process the packet.
354  */
355  last_packet_signature =
356  hash_memory (n->last_rx_pkt, vec_len (n->last_rx_pkt), 0xd00b);
357 
359  n->last_packet_signature == last_packet_signature)
360  {
361  e = CDP_ERROR_CACHE_HIT;
362  }
363  else
364  {
365  /* Actually scan the packet */
366  e = cdp_packet_scan (cm, n);
368  n->last_packet_signature = last_packet_signature;
369  }
370 
371  if (e == CDP_ERROR_NONE)
372  {
373  n->last_heard = vlib_time_now (vm);
374  }
375 
376  return e;
377 }
378 
379 /*
380  * setup neighbor hash table
381  */
382 static clib_error_t *
384 {
385  clib_error_t *error;
386  cdp_main_t *cm = &cdp_main;
387  void vnet_cdp_node_reference (void);
388 
390 
391  if ((error = vlib_call_init_function (vm, cdp_periodic_init)))
392  return error;
393 
394  cm->vlib_main = vm;
395  cm->vnet_main = vnet_get_main ();
396  cm->neighbor_by_sw_if_index = hash_create (0, sizeof (uword));
397 
398  return 0;
399 }
400 
402 
403 
404 static u8 *
405 format_cdp_neighbors (u8 * s, va_list * va)
406 {
407  CLIB_UNUSED (vlib_main_t * vm) = va_arg (*va, vlib_main_t *);
408  cdp_main_t *cm = va_arg (*va, cdp_main_t *);
409  vnet_main_t *vnm = &vnet_main;
410  cdp_neighbor_t *n;
412 
413  s = format (s,
414  "%=25s %=15s %=25s %=10s\n",
415  "Our Port", "Peer System", "Peer Port", "Last Heard");
416 
417  /* *INDENT-OFF* */
418  pool_foreach (n, cm->neighbors,
419  ({
420  hw = vnet_get_sup_hw_interface (vnm, n->sw_if_index);
421 
422  if (n->disabled == 0)
423  s = format (s, "%=25s %=15s %=25s %=10.1f\n",
424  hw->name, n->device_name, n->port_id,
425  n->last_heard);
426  }));
427  /* *INDENT-ON* */
428  return s;
429 }
430 
431 static clib_error_t *
433  unformat_input_t * input, vlib_cli_command_t * cmd)
434 {
435  cdp_main_t *cm = &cdp_main;
436 
437  if (cm->enabled == 0)
438  vlib_cli_output (vm, "CDP is not enabled...");
439  else
440  vlib_cli_output (vm, "%U\n", format_cdp_neighbors, vm, cm);
441 
442  return 0;
443 }
444 
445 /* *INDENT-OFF* */
446 VLIB_CLI_COMMAND (show_cdp_command, static) = {
447  .path = "show cdp",
448  .short_help = "Show cdp command",
449  .function = show_cdp,
450 };
451 /* *INDENT-ON* */
452 
453 
454 /*
455  * packet trace format function, very similar to
456  * cdp_packet_scan except that we call the per TLV format
457  * functions instead of the per TLV processing functions
458  */
459 u8 *
460 cdp_input_format_trace (u8 * s, va_list * args)
461 {
462  CLIB_UNUSED (vlib_main_t * vm) = va_arg (*args, vlib_main_t *);
463  CLIB_UNUSED (vlib_node_t * node) = va_arg (*args, vlib_node_t *);
464  cdp_input_trace_t *t = va_arg (*args, cdp_input_trace_t *);
465  u8 *cur;
466  cdp_hdr_t *h;
467  cdp_tlv_t *tlv;
468  tlv_handler_t *handler;
469  u8 *(*fp) (cdp_tlv_t *);
470 
471  cur = t->data;
472 
473  h = (cdp_hdr_t *) cur;
474  s = format (s, "%U", format_cdp_hdr, h);
475 
476  cur = (u8 *) (h + 1);
477 
478  while (cur < t->data + t->len)
479  {
480  tlv = (cdp_tlv_t *) cur;
481  tlv->t = ntohs (tlv->t);
482  tlv->l = ntohs (tlv->l);
483  if (tlv->t >= ARRAY_LEN (tlv_handlers))
484  {
485  s = format (s, "BAD_TLV\n");
486  break;
487  }
488  handler = &tlv_handlers[tlv->t];
489  fp = handler->format;
490  s = format (s, " %U", fp, tlv);
491  /* tlv length includes (t, l) */
492  cur += tlv->l;
493  }
494 
495  return s;
496 }
497 
498 /*
499  * fd.io coding-style-patch-verification: ON
500  *
501  * Local Variables:
502  * eval: (c-set-style "gnu")
503  * End:
504  */
#define vec_validate(V, I)
Make sure vector is long enough for given index (no header, unspecified alignment) ...
Definition: vec.h:437
char * name
Definition: cdp_input.c:55
#define hash_set(h, key, value)
Definition: hash.h:255
cdp_error_t
Definition: cdp.h:119
static cdp_error_t process_unused_tlv(cdp_main_t *cm, cdp_neighbor_t *n, cdp_tlv_t *t)
Definition: cdp_input.c:155
vnet_main_t * vnet_get_main(void)
Definition: misc.c:47
int enabled
Definition: cdp.h:97
u16 cdp_checksum(void *p, int count)
Definition: cdp_input.c:26
static f64 vlib_time_now(vlib_main_t *vm)
Definition: main.h:225
#define vec_add1(V, E)
Add 1 element to end of vector (unspecified alignment).
Definition: vec.h:523
static u8 * format_cdp_neighbors(u8 *s, va_list *va)
Definition: cdp_input.c:405
int i
u8 packet_template_index
Definition: cdp.h:57
void * process
Definition: cdp_input.c:58
u8 * format(u8 *s, const char *fmt,...)
Definition: format.c:419
cdp_main_t cdp_main
Definition: cdp_input.c:17
static uword vlib_buffer_length_in_chain(vlib_main_t *vm, vlib_buffer_t *b)
Get length in bytes of the buffer chain.
Definition: buffer_funcs.h:250
#define pool_get(P, E)
Allocate an object E from a pool P (unspecified alignment).
Definition: pool.h:228
unsigned char u8
Definition: types.h:56
uword * neighbor_by_sw_if_index
Definition: cdp.h:91
static clib_error_t * cdp_input_init(vlib_main_t *vm)
Definition: cdp_input.c:383
static u8 * format_cdp_hdr(u8 *s, va_list *va)
Definition: cdp_input.c:225
#define pool_foreach(VAR, POOL, BODY)
Iterate through pool.
Definition: pool.h:443
#define VLIB_INIT_FUNCTION(x)
Definition: init.h:156
u8 data[400]
Definition: cdp.h:131
u8 * format_hex_bytes(u8 *s, va_list *va)
Definition: std-formats.c:84
unsigned int u32
Definition: types.h:88
u8 last_packet_signature_valid
Definition: cdp.h:60
#define vlib_call_init_function(vm, x)
Definition: init.h:227
cdp_error_t cdp_input(vlib_main_t *vm, vlib_buffer_t *b0, u32 bi0)
Definition: cdp_input.c:297
vnet_main_t * vnet_main
Definition: cdp.h:104
CLIB_UNUSED(static cdp_error_t process_text_tlv(cdp_main_t *cm, cdp_neighbor_t *n, cdp_tlv_t *t))
#define hash_get(h, key)
Definition: hash.h:249
#define pool_elt_at_index(p, i)
Returns pointer to element at given index.
Definition: pool.h:464
struct _unformat_input_t unformat_input_t
unsigned short u16
Definition: types.h:57
f64 last_heard
Definition: cdp.h:47
cdp_neighbor_t * neighbors
Definition: cdp.h:82
vnet_main_t vnet_main
Definition: misc.c:43
uword last_packet_signature
Definition: cdp.h:61
word fformat(FILE *f, char *fmt,...)
Definition: format.c:453
static uword vlib_buffer_contents(vlib_main_t *vm, u32 buffer_index, u8 *contents)
Copy buffer contents to memory.
Definition: buffer_funcs.h:284
void vnet_cdp_node_reference(void)
Definition: cdp_node.c:205
vlib_main_t * vm
Definition: buffer.c:294
u8 * last_rx_pkt
Definition: cdp.h:70
static int cdp_packet_scan(cdp_main_t *cm, cdp_neighbor_t *n)
Definition: cdp_input.c:251
static clib_error_t * cdp_periodic_init(vlib_main_t *vm)
Definition: cdp_periodic.c:403
u8 ttl_in_seconds
Definition: cdp.h:51
static cdp_error_t process_text_tlv(cdp_main_t *cm, cdp_neighbor_t *n, cdp_tlv_t *t)
Definition: cdp_input.c:112
static cdp_error_t process_generic_tlv(cdp_main_t *cm, cdp_neighbor_t *n, cdp_tlv_t *t)
Definition: cdp_input.c:77
#define ARRAY_LEN(x)
Definition: clib.h:59
#define VLIB_CLI_COMMAND(x,...)
Definition: cli.h:154
#define hash_create(elts, value_bytes)
Definition: hash.h:696
#define ASSERT(truth)
static clib_error_t * show_cdp(vlib_main_t *vm, unformat_input_t *input, vlib_cli_command_t *cmd)
Definition: cdp_input.c:432
uword hash_memory(void *p, word n_bytes, uword state)
Definition: hash.c:224
vlib_main_t * vlib_main
Definition: cdp.h:103
static u8 * format_generic_tlv(u8 *s, va_list *va)
Definition: cdp_input.c:65
void * format
Definition: cdp_input.c:57
size_t count
Definition: vapi.c:46
u8 disabled
Definition: cdp.h:54
#define foreach_text_to_struct_tlv
Definition: cdp_input.c:161
#define vec_len(v)
Number of elements in vector (rvalue-only, NULL tolerant)
u64 uword
Definition: types.h:112
Definition: cdp.h:79
#define vnet_buffer(b)
Definition: buffer.h:360
u8 * cdp_input_format_trace(u8 *s, va_list *args)
Definition: cdp_input.c:460
static cdp_error_t process_cdp_hdr(cdp_main_t *cm, cdp_neighbor_t *n, cdp_hdr_t *h)
Definition: cdp_input.c:235
u32 sw_if_index
Definition: cdp.h:44
void vlib_cli_output(vlib_main_t *vm, char *fmt,...)
Definition: cli.c:681
static u8 * format_text_tlv(u8 *s, va_list *va)
Definition: cdp_input.c:88
Definition: defs.h:46
signed short i16
Definition: types.h:46