2 * Copyright (c) 2015 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:
7 * http://www.apache.org/licenses/LICENSE-2.0
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.
16 #include <vnet/vnet.h>
17 #include <vnet/ip/ip.h>
18 #include <vnet/mpls/mpls.h>
22 * @brief IP Feature Subgraph Ordering.
24 Dynamically compute IP feature subgraph ordering by performing a
25 topological sort across a set of "feature A before feature B" and
26 "feature C after feature B" constraints.
28 Use the topological sort result to set up vnet_config_main_t's for
31 Feature subgraph arcs are simple enough. They start at specific
32 fixed nodes, and end at specific fixed nodes. In between, a
33 per-interface current feature configuration dictates which
34 additional nodes each packet visits. Each so-called feature node
35 can [of course] drop any specific packet.
37 See ip4_forward.c, ip6_forward.c in this directory to see the
38 current rx-unicast, rx-multicast, and tx feature subgraph arc
41 Let's say that we wish to add a new feature to the ip4 unicast
42 feature subgraph arc, which needs to run before @c ip4-lookup. In
43 either base code or a plugin,
45 \#include <vnet/ip/ip_feature_registration.h>
48 and add the new feature as shown:
51 VNET_IP4_UNICAST_FEATURE_INIT (ip4_lookup, static) =
53 .node_name = "my-ip4-unicast-feature",
54 .runs_before = ORDER_CONSTRAINTS {"ip4-lookup", 0}
55 .feature_index = &my_feature_index,
59 Here's the standard coding pattern to enable / disable
60 @c my-ip4-unicast-feature on an interface:
63 ip4_main_t *im = \&ip4_main;
64 ip_lookup_main_t *lm = &im->lookup_main;
65 ip_config_main_t *rx_cm =
66 &lm->feature_config_mains[VNET_IP_RX_UNICAST_FEAT];
68 sw_if_index = <interface-handle>
69 ci = rx_cm->config_index_by_sw_if_index[sw_if_index];
71 ? vnet_config_add_feature
72 : vnet_config_del_feature)
73 (vm, &rx_cm->config_main,
76 0 / * &config struct if feature uses private config data * /,
77 0 / * sizeof config struct if feature uses private config data * /);
78 rx_cm->config_index_by_sw_if_index[sw_if_index] = ci;
81 For tx features, add this line after setting
83 tx_cm->config_index_by_sw_if_index = ci.
87 per-interface "at least one TX feature enabled" bitmap:
90 vnet_config_update_tx_feature_count (lm, tx_cm, sw_if_index, is_add);
93 Here's how to obtain the correct next node index in packet
94 processing code, aka in the implementation of @c my-ip4-unicast-feature:
97 ip_lookup_main_t * lm = sm->ip4_lookup_main;
98 ip_config_main_t * cm = &lm->feature_config_mains[VNET_IP_RX_UNICAST_FEAT];
100 Call @c vnet_get_config_data to set next0, and to advance
101 @c b0->current_config_index:
103 config_data0 = vnet_get_config_data (&cm->config_main,
104 &b0->current_config_index,
106 0 / * sizeof config data * /);
109 Nodes are free to drop or otherwise redirect packets. Packets
110 which "pass" should be enqueued via the next0 arc computed by
111 vnet_get_config_data.
114 static const char *vnet_cast_names[] = VNET_CAST_NAMES;
117 comma_split (u8 * s, u8 ** a, u8 ** b)
121 while (*s && *s != ',')
134 * @brief Initialize a feature graph arc
135 * @param vm vlib main structure pointer
136 * @param vcm vnet config main structure pointer
137 * @param feature_start_nodes names of start-nodes which use this
139 * @param num_feature_start_nodes number of start-nodes
140 * @param first_reg first element in
141 * [an __attribute__((constructor)) function built, or
142 * otherwise created] singly-linked list of feature registrations
143 * @param [out] in_feature_nodes returned vector of
144 * topologically-sorted feature node names, for use in
146 * @returns 0 on success, otherwise an error message. Errors
147 * are fatal since they invariably involve mistyped node-names, or
148 * genuinely missing node-names
151 vnet_feature_arc_init (vlib_main_t * vm,
152 vnet_config_main_t * vcm,
153 char **feature_start_nodes,
154 int num_feature_start_nodes,
155 vnet_ip_feature_registration_t * first_reg,
156 char ***in_feature_nodes)
158 uword *index_by_name;
162 char **these_constraints;
163 char *this_constraint_c;
164 u8 **constraints = 0;
165 u8 *constraint_tuple;
167 u8 **orig, **closure;
171 int a_index, b_index;
174 vnet_ip_feature_registration_t *this_reg = 0;
175 char **feature_nodes = 0;
177 u8 **keys_to_delete = 0;
179 index_by_name = hash_create_string (0, sizeof (uword));
180 reg_by_index = hash_create (0, sizeof (uword));
182 this_reg = first_reg;
184 /* pass 1, collect feature node names, construct a before b pairs */
187 node_name = format (0, "%s%c", this_reg->node_name, 0);
188 hash_set (reg_by_index, vec_len (node_names), (uword) this_reg);
190 hash_set_mem (index_by_name, node_name, vec_len (node_names));
192 vec_add1 (node_names, node_name);
194 these_constraints = this_reg->runs_before;
195 while (these_constraints && these_constraints[0])
197 this_constraint_c = these_constraints[0];
199 constraint_tuple = format (0, "%s,%s%c", node_name,
200 this_constraint_c, 0);
201 vec_add1 (constraints, constraint_tuple);
205 these_constraints = this_reg->runs_after;
206 while (these_constraints && these_constraints[0])
208 this_constraint_c = these_constraints[0];
210 constraint_tuple = format (0, "%s,%s%c",
211 this_constraint_c, node_name, 0);
212 vec_add1 (constraints, constraint_tuple);
216 this_reg = this_reg->next;
219 n_features = vec_len (node_names);
220 orig = clib_ptclosure_alloc (n_features);
222 for (i = 0; i < vec_len (constraints); i++)
224 this_constraint = constraints[i];
226 if (comma_split (this_constraint, &a_name, &b_name))
227 return clib_error_return (0, "comma_split failed!");
229 p = hash_get_mem (index_by_name, a_name);
231 * Note: the next two errors mean that the xxx_FEATURE_INIT macros are
232 * b0rked. As in: if you code "A depends on B," and you forget
233 * to define a FEATURE_INIT macro for B, you lose.
234 * Nonexistent graph nodes are tolerated.
237 return clib_error_return (0, "feature node '%s' not found", a_name);
240 p = hash_get_mem (index_by_name, b_name);
242 return clib_error_return (0, "feature node '%s' not found", b_name);
245 /* add a before b to the original set of constraints */
246 orig[a_index][b_index] = 1;
247 vec_free (this_constraint);
250 /* Compute the positive transitive closure of the original constraints */
251 closure = clib_ptclosure (orig);
253 /* Compute a partial order across feature nodes, if one exists. */
255 for (i = 0; i < n_features; i++)
257 for (j = 0; j < n_features; j++)
260 goto item_constrained;
262 /* Item i can be output */
263 vec_add1 (result, i);
265 for (k = 0; k < n_features; k++)
268 * Add a "Magic" a before a constraint.
269 * This means we'll never output it again
278 /* see if we got a partial order... */
279 if (vec_len (result) != n_features)
280 return clib_error_return (0, "%d feature_init_cast no partial order!");
284 * Bind the index variables, and output the feature node name vector
285 * using the partial order we just computed. Result is in stack
286 * order, because the entry with the fewest constraints (e.g. none)
287 * is output first, etc.
290 for (i = n_features - 1; i >= 0; i--)
292 p = hash_get (reg_by_index, result[i]);
294 this_reg = (vnet_ip_feature_registration_t *) p[0];
295 *this_reg->feature_index = n_features - (i + 1);
296 vec_add1 (feature_nodes, this_reg->node_name);
299 /* Set up the config infrastructure */
300 vnet_config_init (vm, vcm,
302 num_feature_start_nodes,
303 feature_nodes, vec_len (feature_nodes));
305 /* Save a copy for show command */
306 *in_feature_nodes = feature_nodes;
308 /* Finally, clean up all the shit we allocated */
310 hash_foreach_pair (hp, index_by_name,
312 vec_add1 (keys_to_delete, (u8 *)hp->key);
315 hash_free (index_by_name);
316 for (i = 0; i < vec_len (keys_to_delete); i++)
317 vec_free (keys_to_delete[i]);
318 vec_free (keys_to_delete);
319 hash_free (reg_by_index);
321 clib_ptclosure_free (orig);
322 clib_ptclosure_free (closure);
326 #define foreach_af_cast \
327 _(4, VNET_IP_RX_UNICAST_FEAT, "ip4 unicast") \
328 _(4, VNET_IP_RX_MULTICAST_FEAT, "ip4 multicast") \
329 _(4, VNET_IP_TX_FEAT, "ip4 output") \
330 _(6, VNET_IP_RX_UNICAST_FEAT, "ip6 unicast") \
331 _(6, VNET_IP_RX_MULTICAST_FEAT, "ip6 multicast") \
332 _(6, VNET_IP_TX_FEAT, "ip6 output")
334 /** Display the set of available ip features.
335 Useful for verifying that expected features are present
338 static clib_error_t *
339 show_ip_features_command_fn (vlib_main_t * vm,
340 unformat_input_t * input,
341 vlib_cli_command_t * cmd)
343 ip4_main_t *im4 = &ip4_main;
344 ip6_main_t *im6 = &ip6_main;
348 vlib_cli_output (vm, "Available IP feature nodes");
352 features = im##a->feature_nodes[c]; \
353 vlib_cli_output (vm, "%s:", s); \
354 for (i = 0; i < vec_len(features); i++) \
355 vlib_cli_output (vm, " %s\n", features[i]); \
364 * This command is used to display the set of available IP features.
365 * This can be useful for verifying that expected features are present.
368 * Example of how to display the set of available IP features:
369 * @cliexstart{show ip features}
370 * Available IP feature nodes
373 * ip4-source-check-via-rx
374 * ip4-source-check-via-any
375 * ip4-source-and-port-range-check-rx
376 * ip4-policer-classify
384 * ip4-lookup-multicast
386 * ip4-source-and-port-range-check-tx
390 * ip6-policer-classify
404 VLIB_CLI_COMMAND (show_ip_features_command, static) = {
405 .path = "show ip features",
406 .short_help = "show ip features",
407 .function = show_ip_features_command_fn,
411 /** Display the set of IP features configured on a specific interface
415 ip_interface_features_show (vlib_main_t * vm,
417 ip_config_main_t * cm, u32 sw_if_index)
419 u32 node_index, current_config_index;
421 vnet_config_main_t *vcm;
424 vnet_config_feature_t *feat;
428 vlib_cli_output (vm, "%s feature paths configured on %U...",
429 pname, format_vnet_sw_if_index_name,
430 vnet_get_main (), sw_if_index);
432 for (cast = VNET_IP_RX_UNICAST_FEAT; cast < VNET_N_IP_FEAT; cast++)
434 vcm = &(cm[cast].config_main);
436 vlib_cli_output (vm, "\n%s %s:", pname, vnet_cast_names[cast]);
438 if (NULL == cm[cast].config_index_by_sw_if_index ||
439 vec_len (cm[cast].config_index_by_sw_if_index) < sw_if_index)
441 vlib_cli_output (vm, "none configured");
445 current_config_index = vec_elt (cm[cast].config_index_by_sw_if_index,
448 ASSERT (current_config_index
449 < vec_len (vcm->config_pool_index_by_user_index));
451 cfg_index = vcm->config_pool_index_by_user_index[current_config_index];
452 cfg = pool_elt_at_index (vcm->config_pool, cfg_index);
454 for (i = 0; i < vec_len (cfg->features); i++)
456 feat = cfg->features + i;
457 node_index = feat->node_index;
458 n = vlib_get_node (vm, node_index);
459 vlib_cli_output (vm, " %v", n->name);
464 static clib_error_t *
465 show_ip_interface_features_command_fn (vlib_main_t * vm,
466 unformat_input_t * input,
467 vlib_cli_command_t * cmd)
469 vnet_main_t *vnm = vnet_get_main ();
470 ip4_main_t *im4 = &ip4_main;
471 ip_lookup_main_t *lm4 = &im4->lookup_main;
472 ip6_main_t *im6 = &ip6_main;
473 ip_lookup_main_t *lm6 = &im6->lookup_main;
475 ip_lookup_main_t *lm;
478 if (!unformat (input, "%U", unformat_vnet_sw_interface, vnm, &sw_if_index))
479 return clib_error_return (0, "Interface not specified...");
481 vlib_cli_output (vm, "IP feature paths configured on %U...",
482 format_vnet_sw_if_index_name, vnm, sw_if_index);
484 for (af = 0; af < 2; af++)
491 ip_interface_features_show (vm, (af == 0) ? "ip4" : "ip6",
492 lm->feature_config_mains, sw_if_index);
499 * This command is used to display the set of IP features configured
500 * on a specific interface
503 * Example of how to display the set of available IP features on an interface:
504 * @cliexstart{show ip interface features GigabitEthernet2/0/0}
505 * IP feature paths configured on GigabitEthernet2/0/0...
509 * ip4-lookup-multicast
521 VLIB_CLI_COMMAND (show_ip_interface_features_command, static) = {
522 .path = "show ip interface features",
523 .short_help = "show ip interface features <interface>",
524 .function = show_ip_interface_features_command_fn,
529 * fd.io coding-style-patch-verification: ON
532 * eval: (c-set-style "gnu")