libnl  3.2.24-rc1
cls.c
1 /*
2  * lib/route/classifier.c Classifier
3  *
4  * This library is free software; you can redistribute it and/or
5  * modify it under the terms of the GNU Lesser General Public
6  * License as published by the Free Software Foundation version 2.1
7  * of the License.
8  *
9  * Copyright (c) 2003-2013 Thomas Graf <tgraf@suug.ch>
10  */
11 
12 /**
13  * @ingroup tc
14  * @defgroup cls Classifiers
15  * @{
16  */
17 
18 #include <netlink-private/netlink.h>
19 #include <netlink-private/tc.h>
20 #include <netlink/netlink.h>
21 #include <netlink/utils.h>
22 #include <netlink-private/route/tc-api.h>
23 #include <netlink/route/classifier.h>
24 #include <netlink/route/link.h>
25 
26 /** @cond SKIP */
27 #define CLS_ATTR_PRIO (TCA_ATTR_MAX << 1)
28 #define CLS_ATTR_PROTOCOL (TCA_ATTR_MAX << 2)
29 /** @endcond */
30 
31 static struct nl_object_ops cls_obj_ops;
32 static struct nl_cache_ops rtnl_cls_ops;
33 
34 
35 static int cls_build(struct rtnl_cls *cls, int type, int flags,
36  struct nl_msg **result)
37 {
38  int err, prio, proto;
39  struct tcmsg *tchdr;
40  uint32_t required = TCA_ATTR_IFINDEX;
41 
42  if ((cls->ce_mask & required) != required) {
43  APPBUG("ifindex must be specified");
44  return -NLE_MISSING_ATTR;
45  }
46 
47  err = rtnl_tc_msg_build(TC_CAST(cls), type, flags, result);
48  if (err < 0)
49  return err;
50 
51  tchdr = nlmsg_data(nlmsg_hdr(*result));
52  prio = rtnl_cls_get_prio(cls);
53  proto = rtnl_cls_get_protocol(cls);
54  tchdr->tcm_info = TC_H_MAKE(prio << 16, htons(proto));
55 
56  return 0;
57 }
58 
59 /**
60  * @name Allocation/Freeing
61  * @{
62  */
63 
64 struct rtnl_cls *rtnl_cls_alloc(void)
65 {
66  struct rtnl_tc *tc;
67 
68  tc = TC_CAST(nl_object_alloc(&cls_obj_ops));
69  if (tc)
70  tc->tc_type = RTNL_TC_TYPE_CLS;
71 
72  return (struct rtnl_cls *) tc;
73 }
74 
75 void rtnl_cls_put(struct rtnl_cls *cls)
76 {
77  nl_object_put((struct nl_object *) cls);
78 }
79 
80 /** @} */
81 
82 /**
83  * @name Attributes
84  * @{
85  */
86 
87 void rtnl_cls_set_prio(struct rtnl_cls *cls, uint16_t prio)
88 {
89  cls->c_prio = prio;
90  cls->ce_mask |= CLS_ATTR_PRIO;
91 }
92 
93 uint16_t rtnl_cls_get_prio(struct rtnl_cls *cls)
94 {
95  if (cls->ce_mask & CLS_ATTR_PRIO)
96  return cls->c_prio;
97  else
98  return 0;
99 }
100 
101 void rtnl_cls_set_protocol(struct rtnl_cls *cls, uint16_t protocol)
102 {
103  cls->c_protocol = protocol;
104  cls->ce_mask |= CLS_ATTR_PROTOCOL;
105 }
106 
107 uint16_t rtnl_cls_get_protocol(struct rtnl_cls *cls)
108 {
109  if (cls->ce_mask & CLS_ATTR_PROTOCOL)
110  return cls->c_protocol;
111  else
112  return ETH_P_ALL;
113 }
114 
115 /** @} */
116 
117 
118 /**
119  * @name Addition/Modification/Deletion
120  * @{
121  */
122 
123 /**
124  * Build a netlink message requesting the addition of a classifier
125  * @arg cls Classifier to add
126  * @arg flags Additional netlink message flags
127  * @arg result Pointer to store resulting netlink message
128  *
129  * The behaviour of this function is identical to rtnl_cls_add() with
130  * the exception that it will not send the message but return it int the
131  * provided return pointer instead.
132  *
133  * @see rtnl_cls_add()
134  *
135  * @return 0 on success or a negative error code.
136  */
137 int rtnl_cls_build_add_request(struct rtnl_cls *cls, int flags,
138  struct nl_msg **result)
139 {
140  if (!(flags & NLM_F_CREATE) && !(cls->ce_mask & CLS_ATTR_PRIO)) {
141  APPBUG("prio must be specified if not a new classifier");
142  return -NLE_MISSING_ATTR;
143  }
144 
145  return cls_build(cls, RTM_NEWTFILTER, flags, result);
146 }
147 
148 /**
149  * Add/Update classifier
150  * @arg sk Netlink socket
151  * @arg cls Classifier to add/update
152  * @arg flags Additional netlink message flags
153  *
154  * Builds a \c RTM_NEWTFILTER netlink message requesting the addition
155  * of a new classifier and sends the message to the kernel. The
156  * configuration of the classifier is derived from the attributes of
157  * the specified traffic class.
158  *
159  * The following flags may be specified:
160  * - \c NLM_F_CREATE: Create classifier if it does not exist,
161  * otherwise -NLE_OBJ_NOTFOUND is returned.
162  * - \c NLM_F_EXCL: Return -NLE_EXISTS if a classifier with
163  * matching handle exists already.
164  *
165  * Existing classifiers with matching handles will be updated, unless
166  * the flag \c NLM_F_EXCL is specified. If no matching classifier
167  * exists, it will be created if the flag \c NLM_F_CREATE is set,
168  * otherwise the error -NLE_OBJ_NOTFOUND is returned.
169  *
170  * If the parent qdisc does not support classes, the error
171  * \c NLE_OPNOTSUPP is returned.
172  *
173  * After sending, the function will wait for the ACK or an eventual
174  * error message to be received and will therefore block until the
175  * operation has been completed.
176  *
177  * @note Disabling auto-ack (nl_socket_disable_auto_ack()) will cause
178  * this function to return immediately after sending. In this case,
179  * it is the responsibility of the caller to handle any error
180  * messages returned.
181  *
182  * @return 0 on success or a negative error code.
183  */
184 int rtnl_cls_add(struct nl_sock *sk, struct rtnl_cls *cls, int flags)
185 {
186  struct nl_msg *msg;
187  int err;
188 
189  if ((err = rtnl_cls_build_add_request(cls, flags, &msg)) < 0)
190  return err;
191 
192  return nl_send_sync(sk, msg);
193 }
194 
195 /**
196  * Build a netlink message to change classifier attributes
197  * @arg cls classifier to change
198  * @arg flags additional netlink message flags
199  * @arg result Pointer to store resulting message.
200  *
201  * Builds a new netlink message requesting a change of a neigh
202  * attributes. The netlink message header isn't fully equipped with
203  * all relevant fields and must thus be sent out via nl_send_auto_complete()
204  * or supplemented as needed.
205  *
206  * @return 0 on success or a negative error code.
207  */
208 int rtnl_cls_build_change_request(struct rtnl_cls *cls, int flags,
209  struct nl_msg **result)
210 {
211  return cls_build(cls, RTM_NEWTFILTER, NLM_F_REPLACE | flags, result);
212 }
213 
214 /**
215  * Change a classifier
216  * @arg sk Netlink socket.
217  * @arg cls classifier to change
218  * @arg flags additional netlink message flags
219  *
220  * Builds a netlink message by calling rtnl_cls_build_change_request(),
221  * sends the request to the kernel and waits for the next ACK to be
222  * received and thus blocks until the request has been processed.
223  *
224  * @return 0 on sucess or a negative error if an error occured.
225  */
226 int rtnl_cls_change(struct nl_sock *sk, struct rtnl_cls *cls, int flags)
227 {
228  struct nl_msg *msg;
229  int err;
230 
231  if ((err = rtnl_cls_build_change_request(cls, flags, &msg)) < 0)
232  return err;
233 
234  return nl_send_sync(sk, msg);
235 }
236 
237 /**
238  * Build netlink message requesting the deletion of a classifier
239  * @arg cls Classifier to delete
240  * @arg flags Additional netlink message flags
241  * @arg result Pointer to store resulting netlink message
242  *
243  * The behaviour of this function is identical to rtnl_cls_delete() with
244  * the exception that it will not send the message but return it in the
245  * provided return pointer instead.
246  *
247  * @see rtnl_cls_delete()
248  *
249  * @return 0 on success or a negative error code.
250  */
251 int rtnl_cls_build_delete_request(struct rtnl_cls *cls, int flags,
252  struct nl_msg **result)
253 {
254  uint32_t required = CLS_ATTR_PRIO;
255 
256  if ((cls->ce_mask & required) != required) {
257  APPBUG("prio must be specified");
258  return -NLE_MISSING_ATTR;
259  }
260 
261  return cls_build(cls, RTM_DELTFILTER, flags, result);
262 }
263 
264 /**
265  * Delete classifier
266  * @arg sk Netlink socket
267  * @arg cls Classifier to delete
268  * @arg flags Additional netlink message flags
269  *
270  * Builds a \c RTM_DELTFILTER netlink message requesting the deletion
271  * of a classifier and sends the message to the kernel.
272  *
273  * The message is constructed out of the following attributes:
274  * - \c ifindex (required)
275  * - \c prio (required)
276  * - \c protocol (required)
277  * - \c handle (required)
278  * - \c parent (optional, if not specified parent equals root-qdisc)
279  * - \c kind (optional, must match if provided)
280  *
281  * All other classifier attributes including all class type specific
282  * attributes are ignored.
283  *
284  * After sending, the function will wait for the ACK or an eventual
285  * error message to be received and will therefore block until the
286  * operation has been completed.
287  *
288  * @note Disabling auto-ack (nl_socket_disable_auto_ack()) will cause
289  * this function to return immediately after sending. In this case,
290  * it is the responsibility of the caller to handle any error
291  * messages returned.
292  *
293  * @return 0 on success or a negative error code.
294  */
295 int rtnl_cls_delete(struct nl_sock *sk, struct rtnl_cls *cls, int flags)
296 {
297  struct nl_msg *msg;
298  int err;
299 
300  if ((err = rtnl_cls_build_delete_request(cls, flags, &msg)) < 0)
301  return err;
302 
303  return nl_send_sync(sk, msg);
304 }
305 
306 /** @} */
307 
308 /**
309  * @name Cache Related Functions
310  * @{
311  */
312 
313 /**
314  * Allocate a cache and fill it with all configured classifiers
315  * @arg sk Netlink socket
316  * @arg ifindex Interface index of the network device
317  * @arg parent Parent qdisc/traffic class class
318  * @arg result Pointer to store the created cache
319  *
320  * Allocates a new classifier cache and fills it with a list of all
321  * configured classifier attached to the specified parent qdisc/traffic
322  * class on the specified network device. Release the cache with
323  * nl_cache_free().
324  *
325  * @return 0 on success or a negative error code.
326  */
327 int rtnl_cls_alloc_cache(struct nl_sock *sk, int ifindex, uint32_t parent, struct nl_cache **result)
328 {
329  struct nl_cache * cache;
330  int err;
331 
332  if (!(cache = nl_cache_alloc(&rtnl_cls_ops)))
333  return -NLE_NOMEM;
334 
335  cache->c_iarg1 = ifindex;
336  cache->c_iarg2 = parent;
337 
338  if (sk && (err = nl_cache_refill(sk, cache)) < 0) {
339  nl_cache_free(cache);
340  return err;
341  }
342 
343  *result = cache;
344  return 0;
345 }
346 
347 /** @} */
348 
349 static void cls_dump_line(struct rtnl_tc *tc, struct nl_dump_params *p)
350 {
351  struct rtnl_cls *cls = (struct rtnl_cls *) tc;
352  char buf[32];
353 
354  nl_dump(p, " prio %u protocol %s", cls->c_prio,
355  nl_ether_proto2str(cls->c_protocol, buf, sizeof(buf)));
356 }
357 
358 static int cls_msg_parser(struct nl_cache_ops *ops, struct sockaddr_nl *who,
359  struct nlmsghdr *nlh, struct nl_parser_param *pp)
360 {
361  struct rtnl_cls *cls;
362  int err;
363 
364  if (!(cls = rtnl_cls_alloc()))
365  return -NLE_NOMEM;
366 
367  if ((err = rtnl_tc_msg_parse(nlh, TC_CAST(cls))) < 0)
368  goto errout;
369 
370  cls->c_prio = TC_H_MAJ(cls->c_info) >> 16;
371  cls->c_protocol = ntohs(TC_H_MIN(cls->c_info));
372 
373  err = pp->pp_cb(OBJ_CAST(cls), pp);
374 errout:
375  rtnl_cls_put(cls);
376 
377  return err;
378 }
379 
380 static int cls_request_update(struct nl_cache *cache, struct nl_sock *sk)
381 {
382  struct tcmsg tchdr = {
383  .tcm_family = AF_UNSPEC,
384  .tcm_ifindex = cache->c_iarg1,
385  .tcm_parent = cache->c_iarg2,
386  };
387 
388  return nl_send_simple(sk, RTM_GETTFILTER, NLM_F_DUMP, &tchdr,
389  sizeof(tchdr));
390 }
391 
392 static struct rtnl_tc_type_ops cls_ops = {
393  .tt_type = RTNL_TC_TYPE_CLS,
394  .tt_dump_prefix = "cls",
395  .tt_dump = {
396  [NL_DUMP_LINE] = cls_dump_line,
397  },
398 };
399 
400 static struct nl_cache_ops rtnl_cls_ops = {
401  .co_name = "route/cls",
402  .co_hdrsize = sizeof(struct tcmsg),
403  .co_msgtypes = {
404  { RTM_NEWTFILTER, NL_ACT_NEW, "new" },
405  { RTM_DELTFILTER, NL_ACT_DEL, "del" },
406  { RTM_GETTFILTER, NL_ACT_GET, "get" },
407  END_OF_MSGTYPES_LIST,
408  },
409  .co_protocol = NETLINK_ROUTE,
410  .co_request_update = cls_request_update,
411  .co_msg_parser = cls_msg_parser,
412  .co_obj_ops = &cls_obj_ops,
413 };
414 
415 static struct nl_object_ops cls_obj_ops = {
416  .oo_name = "route/cls",
417  .oo_size = sizeof(struct rtnl_cls),
418  .oo_free_data = rtnl_tc_free_data,
419  .oo_clone = rtnl_tc_clone,
420  .oo_dump = {
421  [NL_DUMP_LINE] = rtnl_tc_dump_line,
422  [NL_DUMP_DETAILS] = rtnl_tc_dump_details,
423  [NL_DUMP_STATS] = rtnl_tc_dump_stats,
424  },
425  .oo_compare = rtnl_tc_compare,
426  .oo_id_attrs = (TCA_ATTR_IFINDEX | TCA_ATTR_HANDLE),
427 };
428 
429 static void __init cls_init(void)
430 {
431  rtnl_tc_type_register(&cls_ops);
432  nl_cache_mngt_register(&rtnl_cls_ops);
433 }
434 
435 static void __exit cls_exit(void)
436 {
437  nl_cache_mngt_unregister(&rtnl_cls_ops);
438  rtnl_tc_type_unregister(&cls_ops);
439 }
440 
441 /** @} */