libnl  3.5.0
lookup.c
1 /* SPDX-License-Identifier: LGPL-2.1-only */
2 /*
3  * lib/fib_lookup/lookup.c FIB Lookup
4  *
5  * This library is free software; you can redistribute it and/or
6  * modify it under the terms of the GNU Lesser General Public
7  * License as published by the Free Software Foundation version 2.1
8  * of the License.
9  *
10  * Copyright (c) 2003-2012 Thomas Graf <tgraf@suug.ch>
11  */
12 
13 /**
14  * @ingroup rtnl
15  * @defgroup fib_lookup FIB Lookup
16  * @brief
17  * @{
18  */
19 
20 #include <netlink-private/netlink.h>
21 #include <netlink-private/utils.h>
22 #include <netlink/netlink.h>
23 #include <netlink/attr.h>
24 #include <netlink/utils.h>
25 #include <netlink/object.h>
26 #include <netlink/route/rtnl.h>
27 #include <netlink/route/route.h>
28 #include <netlink/fib_lookup/request.h>
29 #include <netlink/fib_lookup/lookup.h>
30 
31 /** @cond SKIP */
32 static struct nl_cache_ops fib_lookup_ops;
33 static struct nl_object_ops result_obj_ops;
34 
35 /* not exported so far */
36 struct fib_result_nl {
37  uint32_t fl_addr; /* To be looked up*/
38  uint32_t fl_fwmark;
39  unsigned char fl_tos;
40  unsigned char fl_scope;
41  unsigned char tb_id_in;
42 
43  unsigned char tb_id; /* Results */
44  unsigned char prefixlen;
45  unsigned char nh_sel;
46  unsigned char type;
47  unsigned char scope;
48  int err;
49 };
50 /** @endcond */
51 
52 static void result_free_data(struct nl_object *obj)
53 {
54  struct flnl_result *res = nl_object_priv(obj);
55 
56  if (res && res->fr_req)
57  nl_object_put(OBJ_CAST(res->fr_req));
58 }
59 
60 static int result_clone(struct nl_object *_dst, struct nl_object *_src)
61 {
62  struct flnl_result *dst = nl_object_priv(_dst);
63  struct flnl_result *src = nl_object_priv(_src);
64 
65  if (src->fr_req)
66  if (!(dst->fr_req = (struct flnl_request *)
67  nl_object_clone(OBJ_CAST(src->fr_req))))
68  return -NLE_NOMEM;
69 
70  return 0;
71 }
72 
73 static int result_msg_parser(struct nl_cache_ops *ops, struct sockaddr_nl *who,
74  struct nlmsghdr *n, struct nl_parser_param *pp)
75 {
76  struct flnl_result *res;
77  struct fib_result_nl *fr;
78  struct nl_addr *addr;
79  int err = -NLE_INVAL;
80 
81  res = flnl_result_alloc();
82  if (!res)
83  goto errout;
84 
85  res->ce_msgtype = n->nlmsg_type;
86 
87  res->fr_req = flnl_request_alloc();
88  if (!res->fr_req)
89  goto errout;
90 
91  fr = nlmsg_data(n);
92  addr = nl_addr_build(AF_INET, &fr->fl_addr, 4);
93  if (!addr)
94  goto errout;
95  err = flnl_request_set_addr(res->fr_req, addr);
96  nl_addr_put(addr);
97  if (err < 0)
98  goto errout;
99 
100  flnl_request_set_fwmark(res->fr_req, fr->fl_fwmark);
101  flnl_request_set_tos(res->fr_req, fr->fl_tos);
102  flnl_request_set_scope(res->fr_req, fr->fl_scope);
103  flnl_request_set_table(res->fr_req, fr->tb_id_in);
104 
105  res->fr_table_id = fr->tb_id;
106  res->fr_prefixlen = fr->prefixlen;
107  res->fr_nh_sel = fr->nh_sel;
108  res->fr_type = fr->type;
109  res->fr_scope = fr->scope;
110  res->fr_error = fr->err;
111 
112  err = pp->pp_cb((struct nl_object *) res, pp);
113  if (err < 0)
114  goto errout;
115 
116  /* REAL HACK, fib_lookup doesn't support ACK nor does it
117  * send a DONE message, enforce end of message stream
118  * after just the first message */
119  err = NL_STOP;
120 
121 errout:
122  flnl_result_put(res);
123  return err;
124 }
125 
126 static void result_dump_line(struct nl_object *obj, struct nl_dump_params *p)
127 {
128  struct flnl_result *res = (struct flnl_result *) obj;
129  char buf[256];
130 
131  nl_dump_line(p, "table %s prefixlen %u next-hop-selector %u\n",
132  rtnl_route_table2str(res->fr_table_id, buf, sizeof(buf)),
133  res->fr_prefixlen, res->fr_nh_sel);
134  nl_dump_line(p, "type %s ",
135  nl_rtntype2str(res->fr_type, buf, sizeof(buf)));
136  nl_dump(p, "scope %s error %s (%d)\n",
137  rtnl_scope2str(res->fr_scope, buf, sizeof(buf)),
138  nl_strerror_l(-res->fr_error), res->fr_error);
139 }
140 
141 static void result_dump_details(struct nl_object *obj, struct nl_dump_params *p)
142 {
143  result_dump_line(obj, p);
144 }
145 
146 static uint64_t result_compare(struct nl_object *_a, struct nl_object *_b,
147  uint64_t attrs, int flags)
148 {
149  return 0;
150 }
151 
152 /**
153  * @name Allocation/Freeing
154  * @{
155  */
156 
157 struct flnl_result *flnl_result_alloc(void)
158 {
159  return (struct flnl_result *) nl_object_alloc(&result_obj_ops);
160 }
161 
162 void flnl_result_put(struct flnl_result *res)
163 {
164  nl_object_put((struct nl_object *) res);
165 }
166 
167 /** @} */
168 
169 /**
170  * @name Cache Management
171  * @{
172  */
173 
174 /**
175  * Allocate lookup result cache.
176  *
177  * Allocates a new lookup result cache and initializes it properly.
178  *
179  * @note Free the memory after usage using nl_cache_destroy_and_free().
180  * @return Newly allocated cache or NULL if an error occured.
181  */
182 struct nl_cache *flnl_result_alloc_cache(void)
183 {
184  return nl_cache_alloc(&fib_lookup_ops);
185 }
186 
187 /** @} */
188 
189 /**
190  * @name Lookup
191  * @{
192  */
193 
194 /**
195  * Builds a netlink request message to do a lookup
196  * @arg req Requested match.
197  * @arg flags additional netlink message flags
198  * @arg result Result pointer
199  *
200  * Builds a new netlink message requesting a change of link attributes.
201  * The netlink message header isn't fully equipped with all relevant
202  * fields and must be sent out via nl_send_auto_complete() or
203  * supplemented as needed.
204  * \a old must point to a link currently configured in the kernel
205  * and \a tmpl must contain the attributes to be changed set via
206  * \c rtnl_link_set_* functions.
207  *
208  * @return 0 on success or a negative error code.
209  */
210 int flnl_lookup_build_request(struct flnl_request *req, int flags,
211  struct nl_msg **result)
212 {
213  struct nl_msg *msg;
214  struct nl_addr *addr;
215  uint64_t fwmark;
216  int tos, scope, table;
217  struct fib_result_nl fr = {0};
218 
219  fwmark = flnl_request_get_fwmark(req);
220  tos = flnl_request_get_tos(req);
221  scope = flnl_request_get_scope(req);
222  table = flnl_request_get_table(req);
223 
224  fr.fl_fwmark = fwmark != UINT_LEAST64_MAX ? fwmark : 0;
225  fr.fl_tos = tos >= 0 ? tos : 0;
226  fr.fl_scope = scope >= 0 ? scope : RT_SCOPE_UNIVERSE;
227  fr.tb_id_in = table >= 0 ? table : RT_TABLE_UNSPEC;
228 
229  addr = flnl_request_get_addr(req);
230  if (!addr)
231  return -NLE_MISSING_ATTR;
232 
233  fr.fl_addr = *(uint32_t *) nl_addr_get_binary_addr(addr);
234 
235  msg = nlmsg_alloc_simple(0, flags);
236  if (!msg)
237  return -NLE_NOMEM;
238 
239  if (nlmsg_append(msg, &fr, sizeof(fr), NLMSG_ALIGNTO) < 0)
240  goto errout;
241 
242  *result = msg;
243  return 0;
244 
245 errout:
246  nlmsg_free(msg);
247  return -NLE_MSGSIZE;
248 }
249 
250 /**
251  * Perform FIB Lookup
252  * @arg sk Netlink socket.
253  * @arg req Lookup request object.
254  * @arg cache Cache for result.
255  *
256  * Builds a netlink message to request a FIB lookup, waits for the
257  * reply and adds the result to the specified cache.
258  *
259  * @return 0 on success or a negative error code.
260  */
261 int flnl_lookup(struct nl_sock *sk, struct flnl_request *req,
262  struct nl_cache *cache)
263 {
264  struct nl_msg *msg;
265  int err;
266 
267  if ((err = flnl_lookup_build_request(req, 0, &msg)) < 0)
268  return err;
269 
270  err = nl_send_auto_complete(sk, msg);
271  nlmsg_free(msg);
272  if (err < 0)
273  return err;
274 
275  return nl_cache_pickup_checkdup(sk, cache);
276 }
277 
278 /** @} */
279 
280 /**
281  * @name Attribute Access
282  * @{
283  */
284 
285 int flnl_result_get_table_id(struct flnl_result *res)
286 {
287  return res->fr_table_id;
288 }
289 
290 int flnl_result_get_prefixlen(struct flnl_result *res)
291 {
292  return res->fr_prefixlen;
293 }
294 
295 int flnl_result_get_nexthop_sel(struct flnl_result *res)
296 {
297  return res->fr_nh_sel;
298 }
299 
300 int flnl_result_get_type(struct flnl_result *res)
301 {
302  return res->fr_type;
303 }
304 
305 int flnl_result_get_scope(struct flnl_result *res)
306 {
307  return res->fr_scope;
308 }
309 
310 int flnl_result_get_error(struct flnl_result *res)
311 {
312  return res->fr_error;
313 }
314 
315 /** @} */
316 
317 static struct nl_object_ops result_obj_ops = {
318  .oo_name = "fib_lookup/result",
319  .oo_size = sizeof(struct flnl_result),
320  .oo_free_data = result_free_data,
321  .oo_clone = result_clone,
322  .oo_dump = {
323  [NL_DUMP_LINE] = result_dump_line,
324  [NL_DUMP_DETAILS] = result_dump_details,
325  },
326  .oo_compare = result_compare,
327 };
328 
329 static struct nl_cache_ops fib_lookup_ops = {
330  .co_name = "fib_lookup/fib_lookup",
331  .co_hdrsize = sizeof(struct fib_result_nl),
332  .co_msgtypes = {
333  { 0, NL_ACT_UNSPEC, "any" },
334  END_OF_MSGTYPES_LIST,
335  },
336  .co_protocol = NETLINK_FIB_LOOKUP,
337  .co_msg_parser = result_msg_parser,
338  .co_obj_ops = &result_obj_ops,
339 };
340 
341 static void __init fib_lookup_init(void)
342 {
343  nl_cache_mngt_register(&fib_lookup_ops);
344 }
345 
346 static void __exit fib_lookup_exit(void)
347 {
348  nl_cache_mngt_unregister(&fib_lookup_ops);
349 }
350 
351 /** @} */
int nl_send_auto_complete(struct nl_sock *sk, struct nl_msg *msg)
Definition: nl.c:1248
Dump object briefly on one line.
Definition: types.h:22
void nlmsg_free(struct nl_msg *msg)
Release a reference from an netlink message.
Definition: msg.c:565
void * nlmsg_data(const struct nlmsghdr *nlh)
Return pointer to message payload.
Definition: msg.c:107
struct nl_object * nl_object_alloc(struct nl_object_ops *ops)
Allocate a new object of kind specified by the operations handle.
Definition: object.c:55
int nl_cache_mngt_unregister(struct nl_cache_ops *ops)
Unregister a set of cache operations.
Definition: cache_mngt.c:288
struct nl_addr * nl_addr_build(int family, const void *buf, size_t size)
Allocate abstract address based on a binary address.
Definition: addr.c:218
Stop parsing altogether and discard remaining messages.
Definition: handlers.h:68
Dump all attributes but no statistics.
Definition: types.h:23
int nl_cache_pickup_checkdup(struct nl_sock *sk, struct nl_cache *cache)
Pickup a netlink dump response and put it into a cache.
Definition: cache.c:764
int nl_cache_mngt_register(struct nl_cache_ops *ops)
Register a set of cache operations.
Definition: cache_mngt.c:253
int flnl_lookup(struct nl_sock *sk, struct flnl_request *req, struct nl_cache *cache)
Perform FIB Lookup.
Definition: lookup.c:261
int flnl_lookup_build_request(struct flnl_request *req, int flags, struct nl_msg **result)
Builds a netlink request message to do a lookup.
Definition: lookup.c:210
int nlmsg_append(struct nl_msg *n, void *data, size_t len, int pad)
Append data to tail of a netlink message.
Definition: msg.c:449
void nl_object_put(struct nl_object *obj)
Release a reference from an object.
Definition: object.c:216
void nl_addr_put(struct nl_addr *addr)
Decrease the reference counter of an abstract address.
Definition: addr.c:540
struct nl_msg * nlmsg_alloc_simple(int nlmsgtype, int flags)
Allocate a new netlink message.
Definition: msg.c:348
struct nl_cache * flnl_result_alloc_cache(void)
Allocate lookup result cache.
Definition: lookup.c:182
Dumping parameters.
Definition: types.h:33
void nl_dump(struct nl_dump_params *params, const char *fmt,...)
Dump a formatted character string.
Definition: utils.c:962
struct nl_object * nl_object_clone(struct nl_object *obj)
Allocate a new object and copy all data from an existing object.
Definition: object.c:111
void * nl_addr_get_binary_addr(const struct nl_addr *addr)
Get binary address of abstract address object.
Definition: addr.c:942
struct nl_cache * nl_cache_alloc(struct nl_cache_ops *ops)
Allocate new cache.
Definition: cache.c:184