2 * Copyright (c) 2008, 2009, 2010, 2011, 2012, 2013, 2014, 2015 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"
26 #include "openvswitch/ofpbuf.h"
28 #include "unaligned.h"
29 #include "openvswitch/vlog.h"
32 VLOG_DEFINE_THIS_MODULE(netlink);
34 /* A single (bad) Netlink message can in theory dump out many, many log
35 * messages, so the burst size is set quite high here to avoid missing useful
36 * information. Also, at high logging levels we log *all* Netlink messages. */
37 static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(60, 600);
39 /* Returns the nlmsghdr at the head of 'msg'.
41 * 'msg' must be at least as large as a nlmsghdr. */
43 nl_msg_nlmsghdr(const struct ofpbuf *msg)
45 return ofpbuf_at_assert(msg, 0, NLMSG_HDRLEN);
48 /* Returns the genlmsghdr just past 'msg''s nlmsghdr.
50 * Returns a null pointer if 'msg' is not large enough to contain an nlmsghdr
51 * and a genlmsghdr. */
53 nl_msg_genlmsghdr(const struct ofpbuf *msg)
55 return ofpbuf_at(msg, NLMSG_HDRLEN, GENL_HDRLEN);
58 /* If 'buffer' is a NLMSG_ERROR message, stores 0 in '*errorp' if it is an ACK
59 * message, otherwise a positive errno value, and returns true. If 'buffer' is
60 * not an NLMSG_ERROR message, returns false.
62 * 'msg' must be at least as large as a nlmsghdr. */
64 nl_msg_nlmsgerr(const struct ofpbuf *msg, int *errorp)
66 if (nl_msg_nlmsghdr(msg)->nlmsg_type == NLMSG_ERROR) {
67 struct nlmsgerr *err = ofpbuf_at(msg, NLMSG_HDRLEN, sizeof *err);
70 VLOG_ERR_RL(&rl, "received invalid nlmsgerr (%"PRIu32" bytes < %"PRIuSIZE")",
71 msg->size, NLMSG_HDRLEN + sizeof *err);
72 } else if (err->error <= 0 && err->error > INT_MIN) {
84 /* Ensures that 'b' has room for at least 'size' bytes plus netlink padding at
85 * its tail end, reallocating and copying its data if necessary. */
87 nl_msg_reserve(struct ofpbuf *msg, size_t size)
89 ofpbuf_prealloc_tailroom(msg, NLMSG_ALIGN(size));
92 /* Puts a nlmsghdr at the beginning of 'msg', which must be initially empty.
93 * Uses the given 'type' and 'flags'. 'expected_payload' should be
94 * an estimate of the number of payload bytes to be supplied; if the size of
95 * the payload is unknown a value of 0 is acceptable.
97 * 'type' is ordinarily an enumerated value specific to the Netlink protocol
98 * (e.g. RTM_NEWLINK, for NETLINK_ROUTE protocol). For Generic Netlink, 'type'
99 * is the family number obtained via nl_lookup_genl_family().
101 * 'flags' is a bit-mask that indicates what kind of request is being made. It
102 * is often NLM_F_REQUEST indicating that a request is being made, commonly
103 * or'd with NLM_F_ACK to request an acknowledgement.
105 * Sets the new nlmsghdr's nlmsg_len, nlmsg_seq, and nlmsg_pid fields to 0 for
106 * now. Functions that send Netlink messages will fill these in just before
107 * sending the message.
109 * nl_msg_put_genlmsghdr() is more convenient for composing a Generic Netlink
112 nl_msg_put_nlmsghdr(struct ofpbuf *msg,
113 size_t expected_payload, uint32_t type, uint32_t flags)
115 struct nlmsghdr *nlmsghdr;
117 ovs_assert(msg->size == 0);
119 nl_msg_reserve(msg, NLMSG_HDRLEN + expected_payload);
120 nlmsghdr = nl_msg_put_uninit(msg, NLMSG_HDRLEN);
121 nlmsghdr->nlmsg_len = 0;
122 nlmsghdr->nlmsg_type = type;
123 nlmsghdr->nlmsg_flags = flags;
124 nlmsghdr->nlmsg_seq = 0;
125 nlmsghdr->nlmsg_pid = 0;
128 /* Puts a nlmsghdr and genlmsghdr at the beginning of 'msg', which must be
129 * initially empty. 'expected_payload' should be an estimate of the number of
130 * payload bytes to be supplied; if the size of the payload is unknown a value
131 * of 0 is acceptable.
133 * 'family' is the family number obtained via nl_lookup_genl_family().
135 * 'flags' is a bit-mask that indicates what kind of request is being made. It
136 * is often NLM_F_REQUEST indicating that a request is being made, commonly
137 * or'd with NLM_F_ACK to request an acknowledgement.
139 * 'cmd' is an enumerated value specific to the Generic Netlink family
140 * (e.g. CTRL_CMD_NEWFAMILY for the GENL_ID_CTRL family).
142 * 'version' is a version number specific to the family and command (often 1).
144 * Sets the new nlmsghdr's nlmsg_pid field to 0 for now. nl_sock_send() will
145 * fill it in just before sending the message.
147 * nl_msg_put_nlmsghdr() should be used to compose Netlink messages that are
148 * not Generic Netlink messages. */
150 nl_msg_put_genlmsghdr(struct ofpbuf *msg, size_t expected_payload,
151 int family, uint32_t flags, uint8_t cmd, uint8_t version)
153 struct genlmsghdr *genlmsghdr;
155 nl_msg_put_nlmsghdr(msg, GENL_HDRLEN + expected_payload, family, flags);
156 ovs_assert(msg->size == NLMSG_HDRLEN);
157 genlmsghdr = nl_msg_put_uninit(msg, GENL_HDRLEN);
158 genlmsghdr->cmd = cmd;
159 genlmsghdr->version = version;
160 genlmsghdr->reserved = 0;
163 /* Appends the 'size' bytes of data in 'p', plus Netlink padding if needed, to
164 * the tail end of 'msg'. Data in 'msg' is reallocated and copied if
167 nl_msg_put(struct ofpbuf *msg, const void *data, size_t size)
169 memcpy(nl_msg_put_uninit(msg, size), data, size);
172 /* Appends 'size' bytes of data, plus Netlink padding if needed, to the tail
173 * end of 'msg', reallocating and copying its data if necessary. Returns a
174 * pointer to the first byte of the new data, which is left uninitialized. */
176 nl_msg_put_uninit(struct ofpbuf *msg, size_t size)
178 size_t pad = PAD_SIZE(size, NLMSG_ALIGNTO);
179 char *p = ofpbuf_put_uninit(msg, size + pad);
181 memset(p + size, 0, pad);
186 /* Prepends the 'size' bytes of data in 'p', plus Netlink padding if needed, to
187 * the head end of 'msg'. Data in 'msg' is reallocated and copied if
190 nl_msg_push(struct ofpbuf *msg, const void *data, size_t size)
192 memcpy(nl_msg_push_uninit(msg, size), data, size);
195 /* Prepends 'size' bytes of data, plus Netlink padding if needed, to the head
196 * end of 'msg', reallocating and copying its data if necessary. Returns a
197 * pointer to the first byte of the new data, which is left uninitialized. */
199 nl_msg_push_uninit(struct ofpbuf *msg, size_t size)
201 size_t pad = PAD_SIZE(size, NLMSG_ALIGNTO);
202 char *p = ofpbuf_push_uninit(msg, size + pad);
204 memset(p + size, 0, pad);
209 /* Appends a Netlink attribute of the given 'type' and room for 'size' bytes of
210 * data as its payload, plus Netlink padding if needed, to the tail end of
211 * 'msg', reallocating and copying its data if necessary. Returns a pointer to
212 * the first byte of data in the attribute, which is left uninitialized. */
214 nl_msg_put_unspec_uninit(struct ofpbuf *msg, uint16_t type, size_t size)
216 size_t total_size = NLA_HDRLEN + size;
217 struct nlattr* nla = nl_msg_put_uninit(msg, total_size);
218 ovs_assert(!nl_attr_oversized(size));
219 nla->nla_len = total_size;
220 nla->nla_type = type;
224 /* Appends a Netlink attribute of the given 'type' and room for 'size' bytes of
225 * data as its payload, plus Netlink padding if needed, to the tail end of
226 * 'msg', reallocating and copying its data if necessary. Returns a pointer to
227 * the first byte of data in the attribute, which is zeroed. */
229 nl_msg_put_unspec_zero(struct ofpbuf *msg, uint16_t type, size_t size)
231 void *data = nl_msg_put_unspec_uninit(msg, type, size);
232 memset(data, 0, size);
236 /* Appends a Netlink attribute of the given 'type' and the 'size' bytes of
237 * 'data' as its payload, to the tail end of 'msg', reallocating and copying
238 * its data if necessary. Returns a pointer to the first byte of data in the
239 * attribute, which is left uninitialized. */
241 nl_msg_put_unspec(struct ofpbuf *msg, uint16_t type,
242 const void *data, size_t size)
244 memcpy(nl_msg_put_unspec_uninit(msg, type, size), data, size);
247 /* Appends a Netlink attribute of the given 'type' and no payload to 'msg'.
248 * (Some Netlink protocols use the presence or absence of an attribute as a
251 nl_msg_put_flag(struct ofpbuf *msg, uint16_t type)
253 nl_msg_put_unspec(msg, type, NULL, 0);
256 /* Appends a Netlink attribute of the given 'type' and the given 8-bit 'value'
259 nl_msg_put_u8(struct ofpbuf *msg, uint16_t type, uint8_t value)
261 nl_msg_put_unspec(msg, type, &value, sizeof value);
264 /* Appends a Netlink attribute of the given 'type' and the given 16-bit host
265 * byte order 'value' to 'msg'. */
267 nl_msg_put_u16(struct ofpbuf *msg, uint16_t type, uint16_t value)
269 nl_msg_put_unspec(msg, type, &value, sizeof value);
272 /* Appends a Netlink attribute of the given 'type' and the given 32-bit host
273 * byte order 'value' to 'msg'. */
275 nl_msg_put_u32(struct ofpbuf *msg, uint16_t type, uint32_t value)
277 nl_msg_put_unspec(msg, type, &value, sizeof value);
280 /* Appends a Netlink attribute of the given 'type' and the given 64-bit host
281 * byte order 'value' to 'msg'. */
283 nl_msg_put_u64(struct ofpbuf *msg, uint16_t type, uint64_t value)
285 nl_msg_put_unspec(msg, type, &value, sizeof value);
288 /* Appends a Netlink attribute of the given 'type' and the given 16-bit network
289 * byte order 'value' to 'msg'. */
291 nl_msg_put_be16(struct ofpbuf *msg, uint16_t type, ovs_be16 value)
293 nl_msg_put_unspec(msg, type, &value, sizeof value);
296 /* Appends a Netlink attribute of the given 'type' and the given 32-bit network
297 * byte order 'value' to 'msg'. */
299 nl_msg_put_be32(struct ofpbuf *msg, uint16_t type, ovs_be32 value)
301 nl_msg_put_unspec(msg, type, &value, sizeof value);
304 /* Appends a Netlink attribute of the given 'type' and the given 64-bit network
305 * byte order 'value' to 'msg'. */
307 nl_msg_put_be64(struct ofpbuf *msg, uint16_t type, ovs_be64 value)
309 nl_msg_put_unspec(msg, type, &value, sizeof value);
312 /* Appends a Netlink attribute of the given 'type' and the given IPv6
313 * address order 'value' to 'msg'. */
315 nl_msg_put_in6_addr(struct ofpbuf *msg, uint16_t type,
316 const struct in6_addr *value)
318 nl_msg_put_unspec(msg, type, value, sizeof *value);
321 /* Appends a Netlink attribute of the given 'type' and the given odp_port_t
322 * 'value' to 'msg'. */
324 nl_msg_put_odp_port(struct ofpbuf *msg, uint16_t type, odp_port_t value)
326 nl_msg_put_u32(msg, type, odp_to_u32(value));
329 /* Appends a Netlink attribute of the given 'type' with the 'len' characters
330 * of 'value', followed by the null byte to 'msg'. */
332 nl_msg_put_string__(struct ofpbuf *msg, uint16_t type, const char *value,
335 char *data = nl_msg_put_unspec_uninit(msg, type, len + 1);
337 memcpy(data, value, len);
341 /* Appends a Netlink attribute of the given 'type' and the given
342 * null-terminated string 'value' to 'msg'. */
344 nl_msg_put_string(struct ofpbuf *msg, uint16_t type, const char *value)
346 nl_msg_put_unspec(msg, type, value, strlen(value) + 1);
349 /* Prepends a Netlink attribute of the given 'type' and room for 'size' bytes
350 * of data as its payload, plus Netlink padding if needed, to the head end of
351 * 'msg', reallocating and copying its data if necessary. Returns a pointer to
352 * the first byte of data in the attribute, which is left uninitialized. */
354 nl_msg_push_unspec_uninit(struct ofpbuf *msg, uint16_t type, size_t size)
356 size_t total_size = NLA_HDRLEN + size;
357 struct nlattr* nla = nl_msg_push_uninit(msg, total_size);
358 ovs_assert(!nl_attr_oversized(size));
359 nla->nla_len = total_size;
360 nla->nla_type = type;
364 /* Prepends a Netlink attribute of the given 'type' and the 'size' bytes of
365 * 'data' as its payload, to the head end of 'msg', reallocating and copying
366 * its data if necessary. Returns a pointer to the first byte of data in the
367 * attribute, which is left uninitialized. */
369 nl_msg_push_unspec(struct ofpbuf *msg, uint16_t type,
370 const void *data, size_t size)
372 memcpy(nl_msg_push_unspec_uninit(msg, type, size), data, size);
375 /* Prepends a Netlink attribute of the given 'type' and no payload to 'msg'.
376 * (Some Netlink protocols use the presence or absence of an attribute as a
379 nl_msg_push_flag(struct ofpbuf *msg, uint16_t type)
381 nl_msg_push_unspec_uninit(msg, type, 0);
384 /* Prepends a Netlink attribute of the given 'type' and the given 8-bit 'value'
387 nl_msg_push_u8(struct ofpbuf *msg, uint16_t type, uint8_t value)
389 nl_msg_push_unspec(msg, type, &value, sizeof value);
392 /* Prepends a Netlink attribute of the given 'type' and the given 16-bit host
393 * byte order 'value' to 'msg'. */
395 nl_msg_push_u16(struct ofpbuf *msg, uint16_t type, uint16_t value)
397 nl_msg_push_unspec(msg, type, &value, sizeof value);
400 /* Prepends a Netlink attribute of the given 'type' and the given 32-bit host
401 * byte order 'value' to 'msg'. */
403 nl_msg_push_u32(struct ofpbuf *msg, uint16_t type, uint32_t value)
405 nl_msg_push_unspec(msg, type, &value, sizeof value);
408 /* Prepends a Netlink attribute of the given 'type' and the given 64-bit host
409 * byte order 'value' to 'msg'. */
411 nl_msg_push_u64(struct ofpbuf *msg, uint16_t type, uint64_t value)
413 nl_msg_push_unspec(msg, type, &value, sizeof value);
416 /* Prepends a Netlink attribute of the given 'type' and the given 16-bit
417 * network byte order 'value' to 'msg'. */
419 nl_msg_push_be16(struct ofpbuf *msg, uint16_t type, ovs_be16 value)
421 nl_msg_push_unspec(msg, type, &value, sizeof value);
424 /* Prepends a Netlink attribute of the given 'type' and the given 32-bit
425 * network byte order 'value' to 'msg'. */
427 nl_msg_push_be32(struct ofpbuf *msg, uint16_t type, ovs_be32 value)
429 nl_msg_push_unspec(msg, type, &value, sizeof value);
432 /* Prepends a Netlink attribute of the given 'type' and the given 64-bit
433 * network byte order 'value' to 'msg'. */
435 nl_msg_push_be64(struct ofpbuf *msg, uint16_t type, ovs_be64 value)
437 nl_msg_push_unspec(msg, type, &value, sizeof value);
440 /* Prepends a Netlink attribute of the given 'type' and the given
441 * null-terminated string 'value' to 'msg'. */
443 nl_msg_push_string(struct ofpbuf *msg, uint16_t type, const char *value)
445 nl_msg_push_unspec(msg, type, value, strlen(value) + 1);
448 /* Adds the header for nested Netlink attributes to 'msg', with the specified
449 * 'type', and returns the header's offset within 'msg'. The caller should add
450 * the content for the nested Netlink attribute to 'msg' (e.g. using the other
451 * nl_msg_*() functions), and then pass the returned offset to
452 * nl_msg_end_nested() to finish up the nested attributes. */
454 nl_msg_start_nested(struct ofpbuf *msg, uint16_t type)
456 size_t offset = msg->size;
457 nl_msg_put_unspec(msg, type, NULL, 0);
461 /* Finalizes a nested Netlink attribute in 'msg'. 'offset' should be the value
462 * returned by nl_msg_start_nested(). */
464 nl_msg_end_nested(struct ofpbuf *msg, size_t offset)
466 struct nlattr *attr = ofpbuf_at_assert(msg, offset, sizeof *attr);
467 attr->nla_len = msg->size - offset;
470 /* Appends a nested Netlink attribute of the given 'type', with the 'size'
471 * bytes of content starting at 'data', to 'msg'. */
473 nl_msg_put_nested(struct ofpbuf *msg,
474 uint16_t type, const void *data, size_t size)
476 size_t offset = nl_msg_start_nested(msg, type);
477 nl_msg_put(msg, data, size);
478 nl_msg_end_nested(msg, offset);
481 /* If 'buffer' begins with a valid "struct nlmsghdr", pulls the header and its
482 * payload off 'buffer', stores header and payload in 'msg->data' and
483 * 'msg->size', and returns a pointer to the header.
485 * If 'buffer' does not begin with a "struct nlmsghdr" or begins with one that
486 * is invalid, returns NULL and clears 'buffer' and 'msg'. */
488 nl_msg_next(struct ofpbuf *buffer, struct ofpbuf *msg)
490 if (buffer->size >= sizeof(struct nlmsghdr)) {
491 struct nlmsghdr *nlmsghdr = nl_msg_nlmsghdr(buffer);
492 size_t len = nlmsghdr->nlmsg_len;
493 if (len >= sizeof *nlmsghdr && len <= buffer->size) {
494 ofpbuf_use_const(msg, nlmsghdr, len);
495 ofpbuf_pull(buffer, len);
500 ofpbuf_clear(buffer);
506 /* Returns true if a Netlink attribute with a payload that is 'payload_size'
507 * bytes long would be oversized, that is, if it's not possible to create an
508 * nlattr of that size because its size wouldn't fit in the 16-bit nla_len
511 nl_attr_oversized(size_t payload_size)
513 return payload_size > UINT16_MAX - NLA_HDRLEN;
518 /* Returns the bits of 'nla->nla_type' that are significant for determining its
521 nl_attr_type(const struct nlattr *nla)
523 return nla->nla_type & NLA_TYPE_MASK;
526 /* Returns the first byte in the payload of attribute 'nla'. */
528 nl_attr_get(const struct nlattr *nla)
530 ovs_assert(nla->nla_len >= NLA_HDRLEN);
534 /* Returns the number of bytes in the payload of attribute 'nla'. */
536 nl_attr_get_size(const struct nlattr *nla)
538 ovs_assert(nla->nla_len >= NLA_HDRLEN);
539 return nla->nla_len - NLA_HDRLEN;
542 /* Asserts that 'nla''s payload is at least 'size' bytes long, and returns the
543 * first byte of the payload. */
545 nl_attr_get_unspec(const struct nlattr *nla, size_t size)
547 ovs_assert(nla->nla_len >= NLA_HDRLEN + size);
551 /* Returns true if 'nla' is nonnull. (Some Netlink protocols use the presence
552 * or absence of an attribute as a Boolean flag.) */
554 nl_attr_get_flag(const struct nlattr *nla)
559 #define NL_ATTR_GET_AS(NLA, TYPE) \
560 (*(TYPE*) nl_attr_get_unspec(nla, sizeof(TYPE)))
562 /* Returns the 8-bit value in 'nla''s payload.
564 * Asserts that 'nla''s payload is at least 1 byte long. */
566 nl_attr_get_u8(const struct nlattr *nla)
568 return NL_ATTR_GET_AS(nla, uint8_t);
571 /* Returns the 16-bit host byte order value in 'nla''s payload.
573 * Asserts that 'nla''s payload is at least 2 bytes long. */
575 nl_attr_get_u16(const struct nlattr *nla)
577 return NL_ATTR_GET_AS(nla, uint16_t);
580 /* Returns the 32-bit host byte order value in 'nla''s payload.
582 * Asserts that 'nla''s payload is at least 4 bytes long. */
584 nl_attr_get_u32(const struct nlattr *nla)
586 return NL_ATTR_GET_AS(nla, uint32_t);
589 /* Returns the 64-bit host byte order value in 'nla''s payload.
591 * Asserts that 'nla''s payload is at least 8 bytes long. */
593 nl_attr_get_u64(const struct nlattr *nla)
595 const ovs_32aligned_u64 *x = nl_attr_get_unspec(nla, sizeof *x);
596 return get_32aligned_u64(x);
599 /* Returns the 16-bit network byte order value in 'nla''s payload.
601 * Asserts that 'nla''s payload is at least 2 bytes long. */
603 nl_attr_get_be16(const struct nlattr *nla)
605 return NL_ATTR_GET_AS(nla, ovs_be16);
608 /* Returns the 32-bit network byte order value in 'nla''s payload.
610 * Asserts that 'nla''s payload is at least 4 bytes long. */
612 nl_attr_get_be32(const struct nlattr *nla)
614 return NL_ATTR_GET_AS(nla, ovs_be32);
617 /* Returns the 64-bit network byte order value in 'nla''s payload.
619 * Asserts that 'nla''s payload is at least 8 bytes long. */
621 nl_attr_get_be64(const struct nlattr *nla)
623 const ovs_32aligned_be64 *x = nl_attr_get_unspec(nla, sizeof *x);
624 return get_32aligned_be64(x);
627 /* Returns the IPv6 address value in 'nla''s payload.
629 * Asserts that 'nla''s payload is at least 16 bytes long. */
631 nl_attr_get_in6_addr(const struct nlattr *nla)
633 return NL_ATTR_GET_AS(nla, struct in6_addr);
636 /* Returns the 32-bit odp_port_t value in 'nla''s payload.
638 * Asserts that 'nla''s payload is at least 4 bytes long. */
640 nl_attr_get_odp_port(const struct nlattr *nla)
642 return u32_to_odp(nl_attr_get_u32(nla));
645 /* Returns the null-terminated string value in 'nla''s payload.
647 * Asserts that 'nla''s payload contains a null-terminated string. */
649 nl_attr_get_string(const struct nlattr *nla)
651 ovs_assert(nla->nla_len > NLA_HDRLEN);
652 ovs_assert(memchr(nl_attr_get(nla), '\0', nla->nla_len - NLA_HDRLEN));
653 return nl_attr_get(nla);
656 /* Initializes 'nested' to the payload of 'nla'. */
658 nl_attr_get_nested(const struct nlattr *nla, struct ofpbuf *nested)
660 ofpbuf_use_const(nested, nl_attr_get(nla), nl_attr_get_size(nla));
663 /* Default minimum payload size for each type of attribute. */
665 min_attr_len(enum nl_attr_type type)
668 case NL_A_NO_ATTR: return 0;
669 case NL_A_UNSPEC: return 0;
670 case NL_A_U8: return 1;
671 case NL_A_U16: return 2;
672 case NL_A_U32: return 4;
673 case NL_A_U64: return 8;
674 case NL_A_STRING: return 1;
675 case NL_A_FLAG: return 0;
676 case NL_A_IPV6: return 16;
677 case NL_A_NESTED: return 0;
678 case N_NL_ATTR_TYPES: default: OVS_NOT_REACHED();
682 /* Default maximum payload size for each type of attribute. */
684 max_attr_len(enum nl_attr_type type)
687 case NL_A_NO_ATTR: return SIZE_MAX;
688 case NL_A_UNSPEC: return SIZE_MAX;
689 case NL_A_U8: return 1;
690 case NL_A_U16: return 2;
691 case NL_A_U32: return 4;
692 case NL_A_U64: return 8;
693 case NL_A_STRING: return SIZE_MAX;
694 case NL_A_FLAG: return SIZE_MAX;
695 case NL_A_IPV6: return 16;
696 case NL_A_NESTED: return SIZE_MAX;
697 case N_NL_ATTR_TYPES: default: OVS_NOT_REACHED();
702 nl_attr_validate(const struct nlattr *nla, const struct nl_policy *policy)
704 uint16_t type = nl_attr_type(nla);
709 if (policy->type == NL_A_NO_ATTR) {
713 /* Figure out min and max length. */
714 min_len = policy->min_len;
716 min_len = min_attr_len(policy->type);
718 max_len = policy->max_len;
720 max_len = max_attr_len(policy->type);
724 len = nl_attr_get_size(nla);
725 if (len < min_len || len > max_len) {
726 VLOG_DBG_RL(&rl, "attr %"PRIu16" length %"PRIuSIZE" not in "
727 "allowed range %"PRIuSIZE"...%"PRIuSIZE, type, len, min_len, max_len);
731 /* Strings must be null terminated and must not have embedded nulls. */
732 if (policy->type == NL_A_STRING) {
733 if (((char *) nla)[nla->nla_len - 1]) {
734 VLOG_DBG_RL(&rl, "attr %"PRIu16" lacks null at end", type);
737 if (memchr(nla + 1, '\0', len - 1) != NULL) {
738 VLOG_DBG_RL(&rl, "attr %"PRIu16" has bad length", type);
746 /* Parses the 'msg' starting at the given 'nla_offset' as a sequence of Netlink
747 * attributes. 'policy[i]', for 0 <= i < n_attrs, specifies how the attribute
748 * with nla_type == i is parsed; a pointer to attribute i is stored in
749 * attrs[i]. Returns true if successful, false on failure.
751 * If the Netlink attributes in 'msg' follow a Netlink header and a Generic
752 * Netlink header, then 'nla_offset' should be NLMSG_HDRLEN + GENL_HDRLEN. */
754 nl_policy_parse(const struct ofpbuf *msg, size_t nla_offset,
755 const struct nl_policy policy[],
756 struct nlattr *attrs[], size_t n_attrs)
762 memset(attrs, 0, n_attrs * sizeof *attrs);
764 if (msg->size < nla_offset) {
765 VLOG_DBG_RL(&rl, "missing headers in nl_policy_parse");
769 NL_ATTR_FOR_EACH (nla, left, ofpbuf_at(msg, nla_offset, 0),
770 msg->size - nla_offset)
772 uint16_t type = nl_attr_type(nla);
773 if (type < n_attrs && policy[type].type != NL_A_NO_ATTR) {
774 const struct nl_policy *e = &policy[type];
775 if (!nl_attr_validate(nla, e)) {
779 VLOG_DBG_RL(&rl, "duplicate attr %"PRIu16, type);
785 VLOG_DBG_RL(&rl, "attributes followed by garbage");
789 for (i = 0; i < n_attrs; i++) {
790 const struct nl_policy *e = &policy[i];
791 if (!e->optional && e->type != NL_A_NO_ATTR && !attrs[i]) {
792 VLOG_DBG_RL(&rl, "required attr %"PRIuSIZE" missing", i);
799 /* Parses the Netlink attributes within 'nla'. 'policy[i]', for 0 <= i <
800 * n_attrs, specifies how the attribute with nla_type == i is parsed; a pointer
801 * to attribute i is stored in attrs[i]. Returns true if successful, false on
804 nl_parse_nested(const struct nlattr *nla, const struct nl_policy policy[],
805 struct nlattr *attrs[], size_t n_attrs)
809 nl_attr_get_nested(nla, &buf);
810 return nl_policy_parse(&buf, 0, policy, attrs, n_attrs);
813 const struct nlattr *
814 nl_attr_find__(const struct nlattr *attrs, size_t size, uint16_t type)
816 const struct nlattr *nla;
819 NL_ATTR_FOR_EACH (nla, left, attrs, size) {
820 if (nl_attr_type(nla) == type) {
827 /* Returns the first Netlink attribute within 'buf' with the specified 'type',
828 * skipping a header of 'hdr_len' bytes at the beginning of 'buf'.
830 * This function does not validate the attribute's length. */
831 const struct nlattr *
832 nl_attr_find(const struct ofpbuf *buf, size_t hdr_len, uint16_t type)
834 return nl_attr_find__(ofpbuf_at(buf, hdr_len, 0), buf->size - hdr_len,
838 /* Returns the first Netlink attribute within 'nla' with the specified
841 * This function does not validate the attribute's length. */
842 const struct nlattr *
843 nl_attr_find_nested(const struct nlattr *nla, uint16_t type)
845 return nl_attr_find__(nl_attr_get(nla), nl_attr_get_size(nla), type);