2 * Copyright (c) 2008, 2009, 2010, 2011, 2012, 2013 Nicira, Inc.
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at:
8 * http://www.apache.org/licenses/LICENSE-2.0
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
21 #include <sys/types.h>
25 #include "netlink-protocol.h"
28 #include "unaligned.h"
31 VLOG_DEFINE_THIS_MODULE(netlink);
33 /* A single (bad) Netlink message can in theory dump out many, many log
34 * messages, so the burst size is set quite high here to avoid missing useful
35 * information. Also, at high logging levels we log *all* Netlink messages. */
36 static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(60, 600);
38 /* Returns the nlmsghdr at the head of 'msg'.
40 * 'msg' must be at least as large as a nlmsghdr. */
42 nl_msg_nlmsghdr(const struct ofpbuf *msg)
44 return ofpbuf_at_assert(msg, 0, NLMSG_HDRLEN);
47 /* Returns the genlmsghdr just past 'msg''s nlmsghdr.
49 * Returns a null pointer if 'msg' is not large enough to contain an nlmsghdr
50 * and a genlmsghdr. */
52 nl_msg_genlmsghdr(const struct ofpbuf *msg)
54 return ofpbuf_at(msg, NLMSG_HDRLEN, GENL_HDRLEN);
57 /* If 'buffer' is a NLMSG_ERROR message, stores 0 in '*errorp' if it is an ACK
58 * message, otherwise a positive errno value, and returns true. If 'buffer' is
59 * not an NLMSG_ERROR message, returns false.
61 * 'msg' must be at least as large as a nlmsghdr. */
63 nl_msg_nlmsgerr(const struct ofpbuf *msg, int *errorp)
65 if (nl_msg_nlmsghdr(msg)->nlmsg_type == NLMSG_ERROR) {
66 struct nlmsgerr *err = ofpbuf_at(msg, NLMSG_HDRLEN, sizeof *err);
69 VLOG_ERR_RL(&rl, "received invalid nlmsgerr (%zd bytes < %zd)",
70 msg->size, NLMSG_HDRLEN + sizeof *err);
71 } else if (err->error <= 0 && err->error > INT_MIN) {
83 /* Ensures that 'b' has room for at least 'size' bytes plus netlink padding at
84 * its tail end, reallocating and copying its data if necessary. */
86 nl_msg_reserve(struct ofpbuf *msg, size_t size)
88 ofpbuf_prealloc_tailroom(msg, NLMSG_ALIGN(size));
91 /* Puts a nlmsghdr at the beginning of 'msg', which must be initially empty.
92 * Uses the given 'type' and 'flags'. 'expected_payload' should be
93 * an estimate of the number of payload bytes to be supplied; if the size of
94 * the payload is unknown a value of 0 is acceptable.
96 * 'type' is ordinarily an enumerated value specific to the Netlink protocol
97 * (e.g. RTM_NEWLINK, for NETLINK_ROUTE protocol). For Generic Netlink, 'type'
98 * is the family number obtained via nl_lookup_genl_family().
100 * 'flags' is a bit-mask that indicates what kind of request is being made. It
101 * is often NLM_F_REQUEST indicating that a request is being made, commonly
102 * or'd with NLM_F_ACK to request an acknowledgement.
104 * Sets the new nlmsghdr's nlmsg_len, nlmsg_seq, and nlmsg_pid fields to 0 for
105 * now. Functions that send Netlink messages will fill these in just before
106 * sending the message.
108 * nl_msg_put_genlmsghdr() is more convenient for composing a Generic Netlink
111 nl_msg_put_nlmsghdr(struct ofpbuf *msg,
112 size_t expected_payload, uint32_t type, uint32_t flags)
114 struct nlmsghdr *nlmsghdr;
116 ovs_assert(msg->size == 0);
118 nl_msg_reserve(msg, NLMSG_HDRLEN + expected_payload);
119 nlmsghdr = nl_msg_put_uninit(msg, NLMSG_HDRLEN);
120 nlmsghdr->nlmsg_len = 0;
121 nlmsghdr->nlmsg_type = type;
122 nlmsghdr->nlmsg_flags = flags;
123 nlmsghdr->nlmsg_seq = 0;
124 nlmsghdr->nlmsg_pid = 0;
127 /* Puts a nlmsghdr and genlmsghdr at the beginning of 'msg', which must be
128 * initially empty. 'expected_payload' should be an estimate of the number of
129 * payload bytes to be supplied; if the size of the payload is unknown a value
130 * of 0 is acceptable.
132 * 'family' is the family number obtained via nl_lookup_genl_family().
134 * 'flags' is a bit-mask that indicates what kind of request is being made. It
135 * is often NLM_F_REQUEST indicating that a request is being made, commonly
136 * or'd with NLM_F_ACK to request an acknowledgement.
138 * 'cmd' is an enumerated value specific to the Generic Netlink family
139 * (e.g. CTRL_CMD_NEWFAMILY for the GENL_ID_CTRL family).
141 * 'version' is a version number specific to the family and command (often 1).
143 * Sets the new nlmsghdr's nlmsg_pid field to 0 for now. nl_sock_send() will
144 * fill it in just before sending the message.
146 * nl_msg_put_nlmsghdr() should be used to compose Netlink messages that are
147 * not Generic Netlink messages. */
149 nl_msg_put_genlmsghdr(struct ofpbuf *msg, size_t expected_payload,
150 int family, uint32_t flags, uint8_t cmd, uint8_t version)
152 struct genlmsghdr *genlmsghdr;
154 nl_msg_put_nlmsghdr(msg, GENL_HDRLEN + expected_payload, family, flags);
155 ovs_assert(msg->size == NLMSG_HDRLEN);
156 genlmsghdr = nl_msg_put_uninit(msg, GENL_HDRLEN);
157 genlmsghdr->cmd = cmd;
158 genlmsghdr->version = version;
159 genlmsghdr->reserved = 0;
162 /* Appends the 'size' bytes of data in 'p', plus Netlink padding if needed, to
163 * the tail end of 'msg'. Data in 'msg' is reallocated and copied if
166 nl_msg_put(struct ofpbuf *msg, const void *data, size_t size)
168 memcpy(nl_msg_put_uninit(msg, size), data, size);
171 /* Appends 'size' bytes of data, plus Netlink padding if needed, to the tail
172 * end of 'msg', reallocating and copying its data if necessary. Returns a
173 * pointer to the first byte of the new data, which is left uninitialized. */
175 nl_msg_put_uninit(struct ofpbuf *msg, size_t size)
177 size_t pad = NLMSG_ALIGN(size) - size;
178 char *p = ofpbuf_put_uninit(msg, size + pad);
180 memset(p + size, 0, pad);
185 /* Prepends the 'size' bytes of data in 'p', plus Netlink padding if needed, to
186 * the head end of 'msg'. Data in 'msg' is reallocated and copied if
189 nl_msg_push(struct ofpbuf *msg, const void *data, size_t size)
191 memcpy(nl_msg_push_uninit(msg, size), data, size);
194 /* Prepends 'size' bytes of data, plus Netlink padding if needed, to the head
195 * end of 'msg', reallocating and copying its data if necessary. Returns a
196 * pointer to the first byte of the new data, which is left uninitialized. */
198 nl_msg_push_uninit(struct ofpbuf *msg, size_t size)
200 size_t pad = NLMSG_ALIGN(size) - size;
201 char *p = ofpbuf_push_uninit(msg, size + pad);
203 memset(p + size, 0, pad);
208 /* Appends a Netlink attribute of the given 'type' and room for 'size' bytes of
209 * data as its payload, plus Netlink padding if needed, to the tail end of
210 * 'msg', reallocating and copying its data if necessary. Returns a pointer to
211 * the first byte of data in the attribute, which is left uninitialized. */
213 nl_msg_put_unspec_uninit(struct ofpbuf *msg, uint16_t type, size_t size)
215 size_t total_size = NLA_HDRLEN + size;
216 struct nlattr* nla = nl_msg_put_uninit(msg, total_size);
217 ovs_assert(NLA_ALIGN(total_size) <= UINT16_MAX);
218 nla->nla_len = total_size;
219 nla->nla_type = type;
223 /* Appends a Netlink attribute of the given 'type' and the 'size' bytes of
224 * 'data' as its payload, to the tail end of 'msg', reallocating and copying
225 * its data if necessary. Returns a pointer to the first byte of data in the
226 * attribute, which is left uninitialized. */
228 nl_msg_put_unspec(struct ofpbuf *msg, uint16_t type,
229 const void *data, size_t size)
231 memcpy(nl_msg_put_unspec_uninit(msg, type, size), data, size);
234 /* Appends a Netlink attribute of the given 'type' and no payload to 'msg'.
235 * (Some Netlink protocols use the presence or absence of an attribute as a
238 nl_msg_put_flag(struct ofpbuf *msg, uint16_t type)
240 nl_msg_put_unspec(msg, type, NULL, 0);
243 /* Appends a Netlink attribute of the given 'type' and the given 8-bit 'value'
246 nl_msg_put_u8(struct ofpbuf *msg, uint16_t type, uint8_t value)
248 nl_msg_put_unspec(msg, type, &value, sizeof value);
251 /* Appends a Netlink attribute of the given 'type' and the given 16-bit host
252 * byte order 'value' to 'msg'. */
254 nl_msg_put_u16(struct ofpbuf *msg, uint16_t type, uint16_t value)
256 nl_msg_put_unspec(msg, type, &value, sizeof value);
259 /* Appends a Netlink attribute of the given 'type' and the given 32-bit host
260 * byte order 'value' to 'msg'. */
262 nl_msg_put_u32(struct ofpbuf *msg, uint16_t type, uint32_t value)
264 nl_msg_put_unspec(msg, type, &value, sizeof value);
267 /* Appends a Netlink attribute of the given 'type' and the given 64-bit host
268 * byte order 'value' to 'msg'. */
270 nl_msg_put_u64(struct ofpbuf *msg, uint16_t type, uint64_t value)
272 nl_msg_put_unspec(msg, type, &value, sizeof value);
275 /* Appends a Netlink attribute of the given 'type' and the given 16-bit network
276 * byte order 'value' to 'msg'. */
278 nl_msg_put_be16(struct ofpbuf *msg, uint16_t type, ovs_be16 value)
280 nl_msg_put_unspec(msg, type, &value, sizeof value);
283 /* Appends a Netlink attribute of the given 'type' and the given 32-bit network
284 * byte order 'value' to 'msg'. */
286 nl_msg_put_be32(struct ofpbuf *msg, uint16_t type, ovs_be32 value)
288 nl_msg_put_unspec(msg, type, &value, sizeof value);
291 /* Appends a Netlink attribute of the given 'type' and the given 64-bit network
292 * byte order 'value' to 'msg'. */
294 nl_msg_put_be64(struct ofpbuf *msg, uint16_t type, ovs_be64 value)
296 nl_msg_put_unspec(msg, type, &value, sizeof value);
299 /* Appends a Netlink attribute of the given 'type' and the given odp_port_t
300 * 'value' to 'msg'. */
302 nl_msg_put_odp_port(struct ofpbuf *msg, uint16_t type, odp_port_t value)
304 nl_msg_put_u32(msg, type, odp_to_u32(value));
308 /* Appends a Netlink attribute of the given 'type' and the given
309 * null-terminated string 'value' to 'msg'. */
311 nl_msg_put_string(struct ofpbuf *msg, uint16_t type, const char *value)
313 nl_msg_put_unspec(msg, type, value, strlen(value) + 1);
316 /* Prepends a Netlink attribute of the given 'type' and room for 'size' bytes
317 * of data as its payload, plus Netlink padding if needed, to the head end of
318 * 'msg', reallocating and copying its data if necessary. Returns a pointer to
319 * the first byte of data in the attribute, which is left uninitialized. */
321 nl_msg_push_unspec_uninit(struct ofpbuf *msg, uint16_t type, size_t size)
323 size_t total_size = NLA_HDRLEN + size;
324 struct nlattr* nla = nl_msg_push_uninit(msg, total_size);
325 ovs_assert(!nl_attr_oversized(size));
326 nla->nla_len = total_size;
327 nla->nla_type = type;
331 /* Prepends a Netlink attribute of the given 'type' and the 'size' bytes of
332 * 'data' as its payload, to the head end of 'msg', reallocating and copying
333 * its data if necessary. Returns a pointer to the first byte of data in the
334 * attribute, which is left uninitialized. */
336 nl_msg_push_unspec(struct ofpbuf *msg, uint16_t type,
337 const void *data, size_t size)
339 memcpy(nl_msg_push_unspec_uninit(msg, type, size), data, size);
342 /* Prepends a Netlink attribute of the given 'type' and no payload to 'msg'.
343 * (Some Netlink protocols use the presence or absence of an attribute as a
346 nl_msg_push_flag(struct ofpbuf *msg, uint16_t type)
348 nl_msg_push_unspec(msg, type, NULL, 0);
351 /* Prepends a Netlink attribute of the given 'type' and the given 8-bit 'value'
354 nl_msg_push_u8(struct ofpbuf *msg, uint16_t type, uint8_t value)
356 nl_msg_push_unspec(msg, type, &value, sizeof value);
359 /* Prepends a Netlink attribute of the given 'type' and the given 16-bit host
360 * byte order 'value' to 'msg'. */
362 nl_msg_push_u16(struct ofpbuf *msg, uint16_t type, uint16_t value)
364 nl_msg_push_unspec(msg, type, &value, sizeof value);
367 /* Prepends a Netlink attribute of the given 'type' and the given 32-bit host
368 * byte order 'value' to 'msg'. */
370 nl_msg_push_u32(struct ofpbuf *msg, uint16_t type, uint32_t value)
372 nl_msg_push_unspec(msg, type, &value, sizeof value);
375 /* Prepends a Netlink attribute of the given 'type' and the given 64-bit host
376 * byte order 'value' to 'msg'. */
378 nl_msg_push_u64(struct ofpbuf *msg, uint16_t type, uint64_t value)
380 nl_msg_push_unspec(msg, type, &value, sizeof value);
383 /* Prepends a Netlink attribute of the given 'type' and the given 16-bit
384 * network byte order 'value' to 'msg'. */
386 nl_msg_push_be16(struct ofpbuf *msg, uint16_t type, ovs_be16 value)
388 nl_msg_push_unspec(msg, type, &value, sizeof value);
391 /* Prepends a Netlink attribute of the given 'type' and the given 32-bit
392 * network byte order 'value' to 'msg'. */
394 nl_msg_push_be32(struct ofpbuf *msg, uint16_t type, ovs_be32 value)
396 nl_msg_push_unspec(msg, type, &value, sizeof value);
399 /* Prepends a Netlink attribute of the given 'type' and the given 64-bit
400 * network byte order 'value' to 'msg'. */
402 nl_msg_push_be64(struct ofpbuf *msg, uint16_t type, ovs_be64 value)
404 nl_msg_push_unspec(msg, type, &value, sizeof value);
407 /* Prepends a Netlink attribute of the given 'type' and the given
408 * null-terminated string 'value' to 'msg'. */
410 nl_msg_push_string(struct ofpbuf *msg, uint16_t type, const char *value)
412 nl_msg_push_unspec(msg, type, value, strlen(value) + 1);
415 /* Adds the header for nested Netlink attributes to 'msg', with the specified
416 * 'type', and returns the header's offset within 'msg'. The caller should add
417 * the content for the nested Netlink attribute to 'msg' (e.g. using the other
418 * nl_msg_*() functions), and then pass the returned offset to
419 * nl_msg_end_nested() to finish up the nested attributes. */
421 nl_msg_start_nested(struct ofpbuf *msg, uint16_t type)
423 size_t offset = msg->size;
424 nl_msg_put_unspec(msg, type, NULL, 0);
428 /* Finalizes a nested Netlink attribute in 'msg'. 'offset' should be the value
429 * returned by nl_msg_start_nested(). */
431 nl_msg_end_nested(struct ofpbuf *msg, size_t offset)
433 struct nlattr *attr = ofpbuf_at_assert(msg, offset, sizeof *attr);
434 attr->nla_len = msg->size - offset;
437 /* Appends a nested Netlink attribute of the given 'type', with the 'size'
438 * bytes of content starting at 'data', to 'msg'. */
440 nl_msg_put_nested(struct ofpbuf *msg,
441 uint16_t type, const void *data, size_t size)
443 size_t offset = nl_msg_start_nested(msg, type);
444 nl_msg_put(msg, data, size);
445 nl_msg_end_nested(msg, offset);
448 /* If 'buffer' begins with a valid "struct nlmsghdr", pulls the header and its
449 * payload off 'buffer', stores header and payload in 'msg->data' and
450 * 'msg->size', and returns a pointer to the header.
452 * If 'buffer' does not begin with a "struct nlmsghdr" or begins with one that
453 * is invalid, returns NULL without modifying 'buffer'. */
455 nl_msg_next(struct ofpbuf *buffer, struct ofpbuf *msg)
457 if (buffer->size >= sizeof(struct nlmsghdr)) {
458 struct nlmsghdr *nlmsghdr = nl_msg_nlmsghdr(buffer);
459 size_t len = nlmsghdr->nlmsg_len;
460 if (len >= sizeof *nlmsghdr && len <= buffer->size) {
461 ofpbuf_use_const(msg, nlmsghdr, len);
462 ofpbuf_pull(buffer, len);
472 /* Returns true if a Netlink attribute with a payload that is 'payload_size'
473 * bytes long would be oversized, that is, if it's not possible to create an
474 * nlattr of that size because its size wouldn't fit in the 16-bit nla_len
477 nl_attr_oversized(size_t payload_size)
479 return NL_ATTR_SIZE(payload_size) > UINT16_MAX;
484 /* Returns the bits of 'nla->nla_type' that are significant for determining its
487 nl_attr_type(const struct nlattr *nla)
489 return nla->nla_type & NLA_TYPE_MASK;
492 /* Returns the first byte in the payload of attribute 'nla'. */
494 nl_attr_get(const struct nlattr *nla)
496 ovs_assert(nla->nla_len >= NLA_HDRLEN);
500 /* Returns the number of bytes in the payload of attribute 'nla'. */
502 nl_attr_get_size(const struct nlattr *nla)
504 ovs_assert(nla->nla_len >= NLA_HDRLEN);
505 return nla->nla_len - NLA_HDRLEN;
508 /* Asserts that 'nla''s payload is at least 'size' bytes long, and returns the
509 * first byte of the payload. */
511 nl_attr_get_unspec(const struct nlattr *nla, size_t size)
513 ovs_assert(nla->nla_len >= NLA_HDRLEN + size);
517 /* Returns true if 'nla' is nonnull. (Some Netlink protocols use the presence
518 * or absence of an attribute as a Boolean flag.) */
520 nl_attr_get_flag(const struct nlattr *nla)
525 #define NL_ATTR_GET_AS(NLA, TYPE) \
526 (*(TYPE*) nl_attr_get_unspec(nla, sizeof(TYPE)))
528 /* Returns the 8-bit value in 'nla''s payload.
530 * Asserts that 'nla''s payload is at least 1 byte long. */
532 nl_attr_get_u8(const struct nlattr *nla)
534 return NL_ATTR_GET_AS(nla, uint8_t);
537 /* Returns the 16-bit host byte order value in 'nla''s payload.
539 * Asserts that 'nla''s payload is at least 2 bytes long. */
541 nl_attr_get_u16(const struct nlattr *nla)
543 return NL_ATTR_GET_AS(nla, uint16_t);
546 /* Returns the 32-bit host byte order value in 'nla''s payload.
548 * Asserts that 'nla''s payload is at least 4 bytes long. */
550 nl_attr_get_u32(const struct nlattr *nla)
552 return NL_ATTR_GET_AS(nla, uint32_t);
555 /* Returns the 64-bit host byte order value in 'nla''s payload.
557 * Asserts that 'nla''s payload is at least 8 bytes long. */
559 nl_attr_get_u64(const struct nlattr *nla)
561 const ovs_32aligned_u64 *x = nl_attr_get_unspec(nla, sizeof *x);
562 return get_32aligned_u64(x);
565 /* Returns the 16-bit network byte order value in 'nla''s payload.
567 * Asserts that 'nla''s payload is at least 2 bytes long. */
569 nl_attr_get_be16(const struct nlattr *nla)
571 return NL_ATTR_GET_AS(nla, ovs_be16);
574 /* Returns the 32-bit network byte order value in 'nla''s payload.
576 * Asserts that 'nla''s payload is at least 4 bytes long. */
578 nl_attr_get_be32(const struct nlattr *nla)
580 return NL_ATTR_GET_AS(nla, ovs_be32);
583 /* Returns the 64-bit network byte order value in 'nla''s payload.
585 * Asserts that 'nla''s payload is at least 8 bytes long. */
587 nl_attr_get_be64(const struct nlattr *nla)
589 const ovs_32aligned_be64 *x = nl_attr_get_unspec(nla, sizeof *x);
590 return get_32aligned_be64(x);
593 /* Returns the 32-bit odp_port_t value in 'nla''s payload.
595 * Asserts that 'nla''s payload is at least 4 bytes long. */
597 nl_attr_get_odp_port(const struct nlattr *nla)
599 return u32_to_odp(nl_attr_get_u32(nla));
602 /* Returns the null-terminated string value in 'nla''s payload.
604 * Asserts that 'nla''s payload contains a null-terminated string. */
606 nl_attr_get_string(const struct nlattr *nla)
608 ovs_assert(nla->nla_len > NLA_HDRLEN);
609 ovs_assert(memchr(nl_attr_get(nla), '\0', nla->nla_len - NLA_HDRLEN));
610 return nl_attr_get(nla);
613 /* Initializes 'nested' to the payload of 'nla'. */
615 nl_attr_get_nested(const struct nlattr *nla, struct ofpbuf *nested)
617 ofpbuf_use_const(nested, nl_attr_get(nla), nl_attr_get_size(nla));
620 /* Default minimum payload size for each type of attribute. */
622 min_attr_len(enum nl_attr_type type)
625 case NL_A_NO_ATTR: return 0;
626 case NL_A_UNSPEC: return 0;
627 case NL_A_U8: return 1;
628 case NL_A_U16: return 2;
629 case NL_A_U32: return 4;
630 case NL_A_U64: return 8;
631 case NL_A_STRING: return 1;
632 case NL_A_FLAG: return 0;
633 case NL_A_NESTED: return 0;
634 case N_NL_ATTR_TYPES: default: NOT_REACHED();
638 /* Default maximum payload size for each type of attribute. */
640 max_attr_len(enum nl_attr_type type)
643 case NL_A_NO_ATTR: return SIZE_MAX;
644 case NL_A_UNSPEC: return SIZE_MAX;
645 case NL_A_U8: return 1;
646 case NL_A_U16: return 2;
647 case NL_A_U32: return 4;
648 case NL_A_U64: return 8;
649 case NL_A_STRING: return SIZE_MAX;
650 case NL_A_FLAG: return SIZE_MAX;
651 case NL_A_NESTED: return SIZE_MAX;
652 case N_NL_ATTR_TYPES: default: NOT_REACHED();
657 nl_attr_validate(const struct nlattr *nla, const struct nl_policy *policy)
659 uint16_t type = nl_attr_type(nla);
664 if (policy->type == NL_A_NO_ATTR) {
668 /* Figure out min and max length. */
669 min_len = policy->min_len;
671 min_len = min_attr_len(policy->type);
673 max_len = policy->max_len;
675 max_len = max_attr_len(policy->type);
679 len = nl_attr_get_size(nla);
680 if (len < min_len || len > max_len) {
681 VLOG_DBG_RL(&rl, "attr %"PRIu16" length %zu not in "
682 "allowed range %zu...%zu", type, len, min_len, max_len);
686 /* Strings must be null terminated and must not have embedded nulls. */
687 if (policy->type == NL_A_STRING) {
688 if (((char *) nla)[nla->nla_len - 1]) {
689 VLOG_DBG_RL(&rl, "attr %"PRIu16" lacks null at end", type);
692 if (memchr(nla + 1, '\0', len - 1) != NULL) {
693 VLOG_DBG_RL(&rl, "attr %"PRIu16" has bad length", type);
701 /* Parses the 'msg' starting at the given 'nla_offset' as a sequence of Netlink
702 * attributes. 'policy[i]', for 0 <= i < n_attrs, specifies how the attribute
703 * with nla_type == i is parsed; a pointer to attribute i is stored in
704 * attrs[i]. Returns true if successful, false on failure.
706 * If the Netlink attributes in 'msg' follow a Netlink header and a Generic
707 * Netlink header, then 'nla_offset' should be NLMSG_HDRLEN + GENL_HDRLEN. */
709 nl_policy_parse(const struct ofpbuf *msg, size_t nla_offset,
710 const struct nl_policy policy[],
711 struct nlattr *attrs[], size_t n_attrs)
717 memset(attrs, 0, n_attrs * sizeof *attrs);
719 if (msg->size < nla_offset) {
720 VLOG_DBG_RL(&rl, "missing headers in nl_policy_parse");
724 NL_ATTR_FOR_EACH (nla, left, ofpbuf_at(msg, nla_offset, 0),
725 msg->size - nla_offset)
727 uint16_t type = nl_attr_type(nla);
728 if (type < n_attrs && policy[type].type != NL_A_NO_ATTR) {
729 const struct nl_policy *e = &policy[type];
730 if (!nl_attr_validate(nla, e)) {
734 VLOG_DBG_RL(&rl, "duplicate attr %"PRIu16, type);
740 VLOG_DBG_RL(&rl, "attributes followed by garbage");
744 for (i = 0; i < n_attrs; i++) {
745 const struct nl_policy *e = &policy[i];
746 if (!e->optional && e->type != NL_A_NO_ATTR && !attrs[i]) {
747 VLOG_DBG_RL(&rl, "required attr %zu missing", i);
754 /* Parses the Netlink attributes within 'nla'. 'policy[i]', for 0 <= i <
755 * n_attrs, specifies how the attribute with nla_type == i is parsed; a pointer
756 * to attribute i is stored in attrs[i]. Returns true if successful, false on
759 nl_parse_nested(const struct nlattr *nla, const struct nl_policy policy[],
760 struct nlattr *attrs[], size_t n_attrs)
764 nl_attr_get_nested(nla, &buf);
765 return nl_policy_parse(&buf, 0, policy, attrs, n_attrs);
768 const struct nlattr *
769 nl_attr_find__(const struct nlattr *attrs, size_t size, uint16_t type)
771 const struct nlattr *nla;
774 NL_ATTR_FOR_EACH (nla, left, attrs, size) {
775 if (nl_attr_type(nla) == type) {
782 /* Returns the first Netlink attribute within 'buf' with the specified 'type',
783 * skipping a header of 'hdr_len' bytes at the beginning of 'buf'.
785 * This function does not validate the attribute's length. */
786 const struct nlattr *
787 nl_attr_find(const struct ofpbuf *buf, size_t hdr_len, uint16_t type)
789 return nl_attr_find__(ofpbuf_at(buf, hdr_len, 0), buf->size - hdr_len,
793 /* Returns the first Netlink attribute within 'nla' with the specified
796 * This function does not validate the attribute's length. */
797 const struct nlattr *
798 nl_attr_find_nested(const struct nlattr *nla, uint16_t type)
800 return nl_attr_find__(nl_attr_get(nla), nl_attr_get_size(nla), type);