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
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
|
/*
* Copyright (c) 2015 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.
*/
#include <vnet/vnet.h>
#include <vnet/ip/ip.h>
#include <vnet/mpls/mpls.h>
/**
* @file
* @brief IP Feature Subgraph Ordering.
Dynamically compute IP feature subgraph ordering by performing a
topological sort across a set of "feature A before feature B" and
"feature C after feature B" constraints.
Use the topological sort result to set up vnet_config_main_t's for
use at runtime.
Feature subgraph arcs are simple enough. They start at specific
fixed nodes, and end at specific fixed nodes. In between, a
per-interface current feature configuration dictates which
additional nodes each packet visits. Each so-called feature node
can [of course] drop any specific packet.
See ip4_forward.c, ip6_forward.c in this directory to see the
current rx-unicast, rx-multicast, and tx feature subgraph arc
definitions.
Let's say that we wish to add a new feature to the ip4 unicast
feature subgraph arc, which needs to run before @c ip4-lookup. In
either base code or a plugin,
<CODE><PRE>
\#include <vnet/ip/ip_feature_registration.h>
</PRE></CODE>
and add the new feature as shown:
<CODE><PRE>
VNET_IP4_UNICAST_FEATURE_INIT (ip4_lookup, static) =
{
.node_name = "my-ip4-unicast-feature",
.runs_before = ORDER_CONSTRAINTS {"ip4-lookup", 0}
.feature_index = &my_feature_index,
};
</PRE></CODE>
Here's the standard coding pattern to enable / disable
@c my-ip4-unicast-feature on an interface:
<CODE><PRE>
ip4_main_t *im = \&ip4_main;
ip_lookup_main_t *lm = &im->lookup_main;
ip_config_main_t *rx_cm =
&lm->feature_config_mains[VNET_IP_RX_UNICAST_FEAT];
sw_if_index = <interface-handle>
ci = rx_cm->config_index_by_sw_if_index[sw_if_index];
ci = (is_add
? vnet_config_add_feature
: vnet_config_del_feature)
(vm, &rx_cm->config_main,
ci,
my_feature_index,
0 / * &config struct if feature uses private config data * /,
0 / * sizeof config struct if feature uses private config data * /);
rx_cm->config_index_by_sw_if_index[sw_if_index] = ci;
</PRE></CODE>
For tx features, add this line after setting
<CODE><PRE>
tx_cm->config_index_by_sw_if_index = ci.
</PRE></CODE>
This maintains a
per-interface "at least one TX feature enabled" bitmap:
<CODE><PRE>
vnet_config_update_tx_feature_count (lm, tx_cm, sw_if_index, is_add);
</PRE></CODE>
Here's how to obtain the correct next node index in packet
processing code, aka in the implementation of @c my-ip4-unicast-feature:
<CODE><PRE>
ip_lookup_main_t * lm = sm->ip4_lookup_main;
ip_config_main_t * cm = &lm->feature_config_mains[VNET_IP_RX_UNICAST_FEAT];
Call @c vnet_get_config_data to set next0, and to advance
@c b0->current_config_index:
config_data0 = vnet_get_config_data (&cm->config_main,
&b0->current_config_index,
&next0,
0 / * sizeof config data * /);
</PRE></CODE>
Nodes are free to drop or otherwise redirect packets. Packets
which "pass" should be enqueued via the next0 arc computed by
vnet_get_config_data.
*/
static const char *vnet_cast_names[] = VNET_CAST_NAMES;
static int
comma_split (u8 * s, u8 ** a, u8 ** b)
{
*a = s;
while (*s && *s != ',')
s++;
if (*s == ',')
*s = 0;
else
return 1;
*b = (u8 *) (s + 1);
return 0;
}
/**
* @brief Initialize a feature graph arc
* @param vm vlib main structure pointer
* @param vcm vnet config main structure pointer
* @param feature_start_nodes names of start-nodes which use this
* feature graph arc
* @param num_feature_start_nodes number of start-nodes
* @param first_reg first element in
* [an __attribute__((constructor)) function built, or
* otherwise created] singly-linked list of feature registrations
* @param [out] in_feature_nodes returned vector of
* topologically-sorted feature node names, for use in
* show commands
* @returns 0 on success, otherwise an error message. Errors
* are fatal since they invariably involve mistyped node-names, or
* genuinely missing node-names
*/
clib_error_t *
vnet_feature_arc_init (vlib_main_t * vm,
vnet_config_main_t * vcm,
char **feature_start_nodes,
int num_feature_start_nodes,
vnet_ip_feature_registration_t * first_reg,
char ***in_feature_nodes)
{
uword *index_by_name;
uword *reg_by_index;
u8 **node_names = 0;
u8 *node_name;
char **these_constraints;
char *this_constraint_c;
u8 **constraints = 0;
u8 *constraint_tuple;
u8 *this_constraint;
u8 **orig, **closure;
uword *p;
int i, j, k;
u8 *a_name, *b_name;
int a_index, b_index;
int n_features;
u32 *result = 0;
vnet_ip_feature_registration_t *this_reg = 0;
char **feature_nodes = 0;
hash_pair_t *hp;
u8 **keys_to_delete = 0;
index_by_name = hash_create_string (0, sizeof (uword));
reg_by_index = hash_create (0, sizeof (uword));
this_reg = first_reg;
/* pass 1, collect feature node names, construct a before b pairs */
while (this_reg)
{
node_name = format (0, "%s%c", this_reg->node_name, 0);
hash_set (reg_by_index, vec_len (node_names), (uword) this_reg);
hash_set_mem (index_by_name, node_name, vec_len (node_names));
vec_add1 (node_names, node_name);
these_constraints = this_reg->runs_before;
while (these_constraints && these_constraints[0])
{
this_constraint_c = these_constraints[0];
constraint_tuple = format (0, "%s,%s%c", node_name,
this_constraint_c, 0);
vec_add1 (constraints, constraint_tuple);
these_constraints++;
}
these_constraints = this_reg->runs_after;
while (these_constraints && these_constraints[0])
{
this_constraint_c = these_constraints[0];
constraint_tuple = format (0, "%s,%s%c",
this_constraint_c, node_name, 0);
vec_add1 (constraints, constraint_tuple);
these_constraints++;
}
this_reg = this_reg->next;
}
n_features = vec_len (node_names);
orig = clib_ptclosure_alloc (n_features);
for (i = 0; i < vec_len (constraints); i++)
{
this_constraint = constraints[i];
if (comma_split (this_constraint, &a_name, &b_name))
return clib_error_return (0, "comma_split failed!");
p = hash_get_mem (index_by_name, a_name);
/*
* Note: the next two errors mean that the xxx_FEATURE_INIT macros are
* b0rked. As in: if you code "A depends on B," and you forget
* to define a FEATURE_INIT macro for B, you lose.
* Nonexistent graph nodes are tolerated.
*/
if (p == 0)
return clib_error_return (0, "feature node '%s' not found", a_name);
a_index = p[0];
p = hash_get_mem (index_by_name, b_name);
if (p == 0)
return clib_error_return (0, "feature node '%s' not found", b_name);
b_index = p[0];
/* add a before b to the original set of constraints */
orig[a_index][b_index] = 1;
vec_free (this_constraint);
}
/* Compute the positive transitive closure of the original constraints */
closure = clib_ptclosure (orig);
/* Compute a partial order across feature nodes, if one exists. */
again:
for (i = 0; i < n_features; i++)
{
for (j = 0; j < n_features; j++)
{
if (closure[i][j])
goto item_constrained;
}
/* Item i can be output */
vec_add1 (result, i);
{
for (k = 0; k < n_features; k++)
closure[k][i] = 0;
/*
* Add a "Magic" a before a constraint.
* This means we'll never output it again
*/
closure[i][i] = 1;
goto again;
}
item_constrained:
;
}
/* see if we got a partial order... */
if (vec_len (result) != n_features)
return clib_error_return (0, "%d feature_init_cast no partial order!");
/*
* We win.
* Bind the index variables, and output the feature node name vector
* using the partial order we just computed. Result is in stack
* order, because the entry with the fewest constraints (e.g. none)
* is output first, etc.
*/
for (i = n_features - 1; i >= 0; i--)
{
p = hash_get (reg_by_index, result[i]);
ASSERT (p != 0);
this_reg = (vnet_ip_feature_registration_t *) p[0];
*this_reg->feature_index = n_features - (i + 1);
vec_add1 (feature_nodes, this_reg->node_name);
}
/* Set up the config infrastructure */
vnet_config_init (vm, vcm,
feature_start_nodes,
num_feature_start_nodes,
feature_nodes, vec_len (feature_nodes));
/* Save a copy for show command */
*in_feature_nodes = feature_nodes;
/* Finally, clean up all the shit we allocated */
/* *INDENT-OFF* */
hash_foreach_pair (hp, index_by_name,
({
vec_add1 (keys_to_delete, (u8 *)hp->key);
}));
/* *INDENT-ON* */
hash_free (index_by_name);
for (i = 0; i < vec_len (keys_to_delete); i++)
vec_free (keys_to_delete[i]);
vec_free (keys_to_delete);
hash_free (reg_by_index);
vec_free (result);
clib_ptclosure_free (orig);
clib_ptclosure_free (closure);
return 0;
}
#define foreach_af_cast \
_(4, VNET_IP_RX_UNICAST_FEAT, "ip4 unicast") \
_(4, VNET_IP_RX_MULTICAST_FEAT, "ip4 multicast") \
_(4, VNET_IP_TX_FEAT, "ip4 output") \
_(6, VNET_IP_RX_UNICAST_FEAT, "ip6 unicast") \
_(6, VNET_IP_RX_MULTICAST_FEAT, "ip6 multicast") \
_(6, VNET_IP_TX_FEAT, "ip6 output")
/** Display the set of available ip features.
Useful for verifying that expected features are present
*/
static clib_error_t *
show_ip_features_command_fn (vlib_main_t * vm,
unformat_input_t * input,
vlib_cli_command_t * cmd)
{
ip4_main_t *im4 = &ip4_main;
ip6_main_t *im6 = &ip6_main;
int i;
char **features;
vlib_cli_output (vm, "Available IP feature nodes");
#define _(a,c,s) \
do { \
features = im##a->feature_nodes[c]; \
vlib_cli_output (vm, "%s:", s); \
for (i = 0; i < vec_len(features); i++) \
vlib_cli_output (vm, " %s\n", features[i]); \
} while(0);
foreach_af_cast;
#undef _
return 0;
}
/*?
* This command is used to display the set of available IP features.
* This can be useful for verifying that expected features are present.
*
* @cliexpar
* Example of how to display the set of available IP features:
* @cliexstart{show ip features}
* Available IP feature nodes
* ip4 unicast:
* ip4-inacl
* ip4-source-check-via-rx
* ip4-source-check-via-any
* ip4-source-and-port-range-check-rx
* ip4-policer-classify
* ipsec-input-ip4
* vpath-input-ip4
* snat-in2out
* snat-out2in
* ip4-lookup
* ip4 multicast:
* vpath-input-ip4
* ip4-lookup-multicast
* ip4 output:
* ip4-source-and-port-range-check-tx
* interface-output
* ip6 unicast:
* ip6-inacl
* ip6-policer-classify
* ipsec-input-ip6
* l2tp-decap
* vpath-input-ip6
* sir-to-ila
* ip6-lookup
* ip6 multicast:
* vpath-input-ip6
* ip6-lookup
* ip6 output:
* interface-output
* @cliexend
?*/
/* *INDENT-OFF* */
VLIB_CLI_COMMAND (show_ip_features_command, static) = {
.path = "show ip features",
.short_help = "show ip features",
.function = show_ip_features_command_fn,
};
/* *INDENT-ON* */
/** Display the set of IP features configured on a specific interface
*/
void
ip_interface_features_show (vlib_main_t * vm,
const char *pname,
ip_config_main_t * cm, u32 sw_if_index)
{
u32 node_index, current_config_index;
vnet_cast_t cast;
vnet_config_main_t *vcm;
vnet_config_t *cfg;
u32 cfg_index;
vnet_config_feature_t *feat;
vlib_node_t *n;
int i;
vlib_cli_output (vm, "%s feature paths configured on %U...",
pname, format_vnet_sw_if_index_name,
vnet_get_main (), sw_if_index);
for (cast = VNET_IP_RX_UNICAST_FEAT; cast < VNET_N_IP_FEAT; cast++)
{
vcm = &(cm[cast].config_main);
vlib_cli_output (vm, "\n%s %s:", pname, vnet_cast_names[cast]);
if (NULL == cm[cast].config_index_by_sw_if_index ||
vec_len (cm[cast].config_index_by_sw_if_index) < sw_if_index)
{
vlib_cli_output (vm, "none configured");
continue;
}
current_config_index = vec_elt (cm[cast].config_index_by_sw_if_index,
sw_if_index);
ASSERT (current_config_index
< vec_len (vcm->config_pool_index_by_user_index));
cfg_index = vcm->config_pool_index_by_user_index[current_config_index];
cfg = pool_elt_at_index (vcm->config_pool, cfg_index);
for (i = 0; i < vec_len (cfg->features); i++)
{
feat = cfg->features + i;
node_index = feat->node_index;
n = vlib_get_node (vm, node_index);
vlib_cli_output (vm, " %v", n->name);
}
}
}
static clib_error_t *
show_ip_interface_features_command_fn (vlib_main_t * vm,
unformat_input_t * input,
vlib_cli_command_t * cmd)
{
vnet_main_t *vnm = vnet_get_main ();
ip4_main_t *im4 = &ip4_main;
ip_lookup_main_t *lm4 = &im4->lookup_main;
ip6_main_t *im6 = &ip6_main;
ip_lookup_main_t *lm6 = &im6->lookup_main;
ip_lookup_main_t *lm;
u32 sw_if_index, af;
if (!unformat (input, "%U", unformat_vnet_sw_interface, vnm, &sw_if_index))
return clib_error_return (0, "Interface not specified...");
vlib_cli_output (vm, "IP feature paths configured on %U...",
format_vnet_sw_if_index_name, vnm, sw_if_index);
for (af = 0; af < 2; af++)
{
if (af == 0)
lm = lm4;
else
lm = lm6;
ip_interface_features_show (vm, (af == 0) ? "ip4" : "ip6",
lm->feature_config_mains, sw_if_index);
}
return 0;
}
/*?
* This command is used to display the set of IP features configured
* on a specific interface
*
* @cliexpar
* Example of how to display the set of available IP features on an interface:
* @cliexstart{show ip interface features GigabitEthernet2/0/0}
* IP feature paths configured on GigabitEthernet2/0/0...
* ipv4 unicast:
* ip4-lookup
* ipv4 multicast:
* ip4-lookup-multicast
* ipv4 multicast:
* interface-output
* ipv6 unicast:
* ip6-lookup
* ipv6 multicast:
* ip6-lookup
* ipv6 multicast:
* interface-output
* @cliexend
?*/
/* *INDENT-OFF* */
VLIB_CLI_COMMAND (show_ip_interface_features_command, static) = {
.path = "show ip interface features",
.short_help = "show ip interface features <interface>",
.function = show_ip_interface_features_command_fn,
};
/* *INDENT-ON* */
/*
* fd.io coding-style-patch-verification: ON
*
* Local Variables:
* eval: (c-set-style "gnu")
* End:
*/
|