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2 * Copyright (c) 2008, 2009, 2010, 2011 Nicira Networks.
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.
22 #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
));
94 /* Next nlmsghdr sequence number.
96 * This implementation uses sequence numbers that are unique process-wide,
97 * to avoid a hypothetical race: send request, close socket, open new
98 * socket that reuses the old socket's PID value, send request on new
99 * socket, receive reply from kernel to old socket but with same PID and
100 * sequence number. (This race could be avoided other ways, e.g. by
101 * preventing PIDs from being quickly reused). */
102 static uint32_t next_seq
;
105 /* Pick initial sequence number. */
106 next_seq
= getpid() ^ time_wall();
111 /* Puts a nlmsghdr at the beginning of 'msg', which must be initially empty.
112 * Uses the given 'type' and 'flags'. 'expected_payload' should be
113 * an estimate of the number of payload bytes to be supplied; if the size of
114 * the payload is unknown a value of 0 is acceptable.
116 * 'type' is ordinarily an enumerated value specific to the Netlink protocol
117 * (e.g. RTM_NEWLINK, for NETLINK_ROUTE protocol). For Generic Netlink, 'type'
118 * is the family number obtained via nl_lookup_genl_family().
120 * 'flags' is a bit-mask that indicates what kind of request is being made. It
121 * is often NLM_F_REQUEST indicating that a request is being made, commonly
122 * or'd with NLM_F_ACK to request an acknowledgement.
124 * Sets the new nlmsghdr's nlmsg_pid field to 0 for now. nl_sock_send() will
125 * fill it in just before sending the message.
127 * nl_msg_put_genlmsghdr() is more convenient for composing a Generic Netlink
130 nl_msg_put_nlmsghdr(struct ofpbuf
*msg
,
131 size_t expected_payload
, uint32_t type
, uint32_t flags
)
133 struct nlmsghdr
*nlmsghdr
;
135 assert(msg
->size
== 0);
137 nl_msg_reserve(msg
, NLMSG_HDRLEN
+ expected_payload
);
138 nlmsghdr
= nl_msg_put_uninit(msg
, NLMSG_HDRLEN
);
139 nlmsghdr
->nlmsg_len
= 0;
140 nlmsghdr
->nlmsg_type
= type
;
141 nlmsghdr
->nlmsg_flags
= flags
;
142 nlmsghdr
->nlmsg_seq
= get_nlmsg_seq();
143 nlmsghdr
->nlmsg_pid
= 0;
146 /* Puts a nlmsghdr and genlmsghdr at the beginning of 'msg', which must be
147 * initially empty. 'expected_payload' should be an estimate of the number of
148 * payload bytes to be supplied; if the size of the payload is unknown a value
149 * of 0 is acceptable.
151 * 'family' is the family number obtained via nl_lookup_genl_family().
153 * 'flags' is a bit-mask that indicates what kind of request is being made. It
154 * is often NLM_F_REQUEST indicating that a request is being made, commonly
155 * or'd with NLM_F_ACK to request an acknowledgement.
157 * 'cmd' is an enumerated value specific to the Generic Netlink family
158 * (e.g. CTRL_CMD_NEWFAMILY for the GENL_ID_CTRL family).
160 * 'version' is a version number specific to the family and command (often 1).
162 * Sets the new nlmsghdr's nlmsg_pid field to 0 for now. nl_sock_send() will
163 * fill it in just before sending the message.
165 * nl_msg_put_nlmsghdr() should be used to compose Netlink messages that are
166 * not Generic Netlink messages. */
168 nl_msg_put_genlmsghdr(struct ofpbuf
*msg
, size_t expected_payload
,
169 int family
, uint32_t flags
, uint8_t cmd
, uint8_t version
)
171 struct genlmsghdr
*genlmsghdr
;
173 nl_msg_put_nlmsghdr(msg
, GENL_HDRLEN
+ expected_payload
, family
, flags
);
174 assert(msg
->size
== NLMSG_HDRLEN
);
175 genlmsghdr
= nl_msg_put_uninit(msg
, GENL_HDRLEN
);
176 genlmsghdr
->cmd
= cmd
;
177 genlmsghdr
->version
= version
;
178 genlmsghdr
->reserved
= 0;
181 /* Appends the 'size' bytes of data in 'p', plus Netlink padding if needed, to
182 * the tail end of 'msg'. Data in 'msg' is reallocated and copied if
185 nl_msg_put(struct ofpbuf
*msg
, const void *data
, size_t size
)
187 memcpy(nl_msg_put_uninit(msg
, size
), data
, size
);
190 /* Appends 'size' bytes of data, plus Netlink padding if needed, to the tail
191 * end of 'msg', reallocating and copying its data if necessary. Returns a
192 * pointer to the first byte of the new data, which is left uninitialized. */
194 nl_msg_put_uninit(struct ofpbuf
*msg
, size_t size
)
196 size_t pad
= NLMSG_ALIGN(size
) - size
;
197 char *p
= ofpbuf_put_uninit(msg
, size
+ pad
);
199 memset(p
+ size
, 0, pad
);
204 /* Appends a Netlink attribute of the given 'type' and room for 'size' bytes of
205 * data as its payload, plus Netlink padding if needed, to the tail end of
206 * 'msg', reallocating and copying its data if necessary. Returns a pointer to
207 * the first byte of data in the attribute, which is left uninitialized. */
209 nl_msg_put_unspec_uninit(struct ofpbuf
*msg
, uint16_t type
, size_t size
)
211 size_t total_size
= NLA_HDRLEN
+ size
;
212 struct nlattr
* nla
= nl_msg_put_uninit(msg
, total_size
);
213 assert(NLA_ALIGN(total_size
) <= UINT16_MAX
);
214 nla
->nla_len
= total_size
;
215 nla
->nla_type
= type
;
219 /* Appends a Netlink attribute of the given 'type' and the 'size' bytes of
220 * 'data' as its payload, to the tail end of 'msg', reallocating and copying
221 * its data if necessary. Returns a pointer to the first byte of data in the
222 * attribute, which is left uninitialized. */
224 nl_msg_put_unspec(struct ofpbuf
*msg
, uint16_t type
,
225 const void *data
, size_t size
)
227 memcpy(nl_msg_put_unspec_uninit(msg
, type
, size
), data
, size
);
230 /* Appends a Netlink attribute of the given 'type' and no payload to 'msg'.
231 * (Some Netlink protocols use the presence or absence of an attribute as a
234 nl_msg_put_flag(struct ofpbuf
*msg
, uint16_t type
)
236 nl_msg_put_unspec(msg
, type
, NULL
, 0);
239 /* Appends a Netlink attribute of the given 'type' and the given 8-bit 'value'
242 nl_msg_put_u8(struct ofpbuf
*msg
, uint16_t type
, uint8_t value
)
244 nl_msg_put_unspec(msg
, type
, &value
, sizeof value
);
247 /* Appends a Netlink attribute of the given 'type' and the given 16-bit host
248 * byte order 'value' to 'msg'. */
250 nl_msg_put_u16(struct ofpbuf
*msg
, uint16_t type
, uint16_t value
)
252 nl_msg_put_unspec(msg
, type
, &value
, sizeof value
);
255 /* Appends a Netlink attribute of the given 'type' and the given 32-bit host
256 * byte order 'value' to 'msg'. */
258 nl_msg_put_u32(struct ofpbuf
*msg
, uint16_t type
, uint32_t value
)
260 nl_msg_put_unspec(msg
, type
, &value
, sizeof value
);
263 /* Appends a Netlink attribute of the given 'type' and the given 64-bit host
264 * byte order 'value' to 'msg'. */
266 nl_msg_put_u64(struct ofpbuf
*msg
, uint16_t type
, uint64_t value
)
268 nl_msg_put_unspec(msg
, type
, &value
, sizeof value
);
271 /* Appends a Netlink attribute of the given 'type' and the given 16-bit network
272 * byte order 'value' to 'msg'. */
274 nl_msg_put_be16(struct ofpbuf
*msg
, uint16_t type
, ovs_be16 value
)
276 nl_msg_put_unspec(msg
, type
, &value
, sizeof value
);
279 /* Appends a Netlink attribute of the given 'type' and the given 32-bit network
280 * byte order 'value' to 'msg'. */
282 nl_msg_put_be32(struct ofpbuf
*msg
, uint16_t type
, ovs_be32 value
)
284 nl_msg_put_unspec(msg
, type
, &value
, sizeof value
);
287 /* Appends a Netlink attribute of the given 'type' and the given 64-bit network
288 * byte order 'value' to 'msg'. */
290 nl_msg_put_be64(struct ofpbuf
*msg
, uint16_t type
, ovs_be64 value
)
292 nl_msg_put_unspec(msg
, type
, &value
, sizeof value
);
295 /* Appends a Netlink attribute of the given 'type' and the given
296 * null-terminated string 'value' to 'msg'. */
298 nl_msg_put_string(struct ofpbuf
*msg
, uint16_t type
, const char *value
)
300 nl_msg_put_unspec(msg
, type
, value
, strlen(value
) + 1);
303 /* Adds the header for nested Netlink attributes to 'msg', with the specified
304 * 'type', and returns the header's offset within 'msg'. The caller should add
305 * the content for the nested Netlink attribute to 'msg' (e.g. using the other
306 * nl_msg_*() functions), and then pass the returned offset to
307 * nl_msg_end_nested() to finish up the nested attributes. */
309 nl_msg_start_nested(struct ofpbuf
*msg
, uint16_t type
)
311 size_t offset
= msg
->size
;
312 nl_msg_put_unspec(msg
, type
, NULL
, 0);
316 /* Finalizes a nested Netlink attribute in 'msg'. 'offset' should be the value
317 * returned by nl_msg_start_nested(). */
319 nl_msg_end_nested(struct ofpbuf
*msg
, size_t offset
)
321 struct nlattr
*attr
= ofpbuf_at_assert(msg
, offset
, sizeof *attr
);
322 attr
->nla_len
= msg
->size
- offset
;
325 /* Appends a nested Netlink attribute of the given 'type', with the 'size'
326 * bytes of content starting at 'data', to 'msg'. */
328 nl_msg_put_nested(struct ofpbuf
*msg
,
329 uint16_t type
, const void *data
, size_t size
)
331 size_t offset
= nl_msg_start_nested(msg
, type
);
332 nl_msg_put(msg
, data
, size
);
333 nl_msg_end_nested(msg
, offset
);
336 /* If 'buffer' begins with a valid "struct nlmsghdr", pulls the header and its
337 * payload off 'buffer', stores header and payload in 'msg->data' and
338 * 'msg->size', and returns a pointer to the header.
340 * If 'buffer' does not begin with a "struct nlmsghdr" or begins with one that
341 * is invalid, returns NULL without modifying 'buffer'. */
343 nl_msg_next(struct ofpbuf
*buffer
, struct ofpbuf
*msg
)
345 if (buffer
->size
>= sizeof(struct nlmsghdr
)) {
346 struct nlmsghdr
*nlmsghdr
= nl_msg_nlmsghdr(buffer
);
347 size_t len
= nlmsghdr
->nlmsg_len
;
348 if (len
>= sizeof *nlmsghdr
&& len
<= buffer
->size
) {
349 ofpbuf_use_const(msg
, nlmsghdr
, len
);
350 ofpbuf_pull(buffer
, len
);
362 /* Returns the bits of 'nla->nla_type' that are significant for determining its
365 nl_attr_type(const struct nlattr
*nla
)
367 return nla
->nla_type
& NLA_TYPE_MASK
;
370 /* Returns the first byte in the payload of attribute 'nla'. */
372 nl_attr_get(const struct nlattr
*nla
)
374 assert(nla
->nla_len
>= NLA_HDRLEN
);
378 /* Returns the number of bytes in the payload of attribute 'nla'. */
380 nl_attr_get_size(const struct nlattr
*nla
)
382 assert(nla
->nla_len
>= NLA_HDRLEN
);
383 return nla
->nla_len
- NLA_HDRLEN
;
386 /* Asserts that 'nla''s payload is at least 'size' bytes long, and returns the
387 * first byte of the payload. */
389 nl_attr_get_unspec(const struct nlattr
*nla
, size_t size
)
391 assert(nla
->nla_len
>= NLA_HDRLEN
+ size
);
395 /* Returns true if 'nla' is nonnull. (Some Netlink protocols use the presence
396 * or absence of an attribute as a Boolean flag.) */
398 nl_attr_get_flag(const struct nlattr
*nla
)
403 #define NL_ATTR_GET_AS(NLA, TYPE) \
404 (*(TYPE*) nl_attr_get_unspec(nla, sizeof(TYPE)))
406 /* Returns the 8-bit value in 'nla''s payload.
408 * Asserts that 'nla''s payload is at least 1 byte long. */
410 nl_attr_get_u8(const struct nlattr
*nla
)
412 return NL_ATTR_GET_AS(nla
, uint8_t);
415 /* Returns the 16-bit host byte order value in 'nla''s payload.
417 * Asserts that 'nla''s payload is at least 2 bytes long. */
419 nl_attr_get_u16(const struct nlattr
*nla
)
421 return NL_ATTR_GET_AS(nla
, uint16_t);
424 /* Returns the 32-bit host byte order value in 'nla''s payload.
426 * Asserts that 'nla''s payload is at least 4 bytes long. */
428 nl_attr_get_u32(const struct nlattr
*nla
)
430 return NL_ATTR_GET_AS(nla
, uint32_t);
433 /* Returns the 64-bit host byte order value in 'nla''s payload.
435 * Asserts that 'nla''s payload is at least 8 bytes long. */
437 nl_attr_get_u64(const struct nlattr
*nla
)
439 const ovs_32aligned_u64
*x
= nl_attr_get_unspec(nla
, sizeof *x
);
440 return get_32aligned_u64(x
);
443 /* Returns the 16-bit network byte order value in 'nla''s payload.
445 * Asserts that 'nla''s payload is at least 2 bytes long. */
447 nl_attr_get_be16(const struct nlattr
*nla
)
449 return NL_ATTR_GET_AS(nla
, ovs_be16
);
452 /* Returns the 32-bit network byte order value in 'nla''s payload.
454 * Asserts that 'nla''s payload is at least 4 bytes long. */
456 nl_attr_get_be32(const struct nlattr
*nla
)
458 return NL_ATTR_GET_AS(nla
, ovs_be32
);
461 /* Returns the 64-bit network byte order value in 'nla''s payload.
463 * Asserts that 'nla''s payload is at least 8 bytes long. */
465 nl_attr_get_be64(const struct nlattr
*nla
)
467 const ovs_32aligned_be64
*x
= nl_attr_get_unspec(nla
, sizeof *x
);
468 return get_32aligned_be64(x
);
471 /* Returns the null-terminated string value in 'nla''s payload.
473 * Asserts that 'nla''s payload contains a null-terminated string. */
475 nl_attr_get_string(const struct nlattr
*nla
)
477 assert(nla
->nla_len
> NLA_HDRLEN
);
478 assert(memchr(nl_attr_get(nla
), '\0', nla
->nla_len
- NLA_HDRLEN
) != NULL
);
479 return nl_attr_get(nla
);
482 /* Initializes 'nested' to the payload of 'nla'. */
484 nl_attr_get_nested(const struct nlattr
*nla
, struct ofpbuf
*nested
)
486 ofpbuf_use_const(nested
, nl_attr_get(nla
), nl_attr_get_size(nla
));
489 /* Default minimum and maximum payload sizes for each type of attribute. */
490 static const size_t attr_len_range
[][2] = {
491 [0 ... N_NL_ATTR_TYPES
- 1] = { 0, SIZE_MAX
},
492 [NL_A_U8
] = { 1, 1 },
493 [NL_A_U16
] = { 2, 2 },
494 [NL_A_U32
] = { 4, 4 },
495 [NL_A_U64
] = { 8, 8 },
496 [NL_A_STRING
] = { 1, SIZE_MAX
},
497 [NL_A_FLAG
] = { 0, SIZE_MAX
},
498 [NL_A_NESTED
] = { 0, SIZE_MAX
},
501 /* Parses the 'msg' starting at the given 'nla_offset' as a sequence of Netlink
502 * attributes. 'policy[i]', for 0 <= i < n_attrs, specifies how the attribute
503 * with nla_type == i is parsed; a pointer to attribute i is stored in
504 * attrs[i]. Returns true if successful, false on failure.
506 * If the Netlink attributes in 'msg' follow a Netlink header and a Generic
507 * Netlink header, then 'nla_offset' should be NLMSG_HDRLEN + GENL_HDRLEN. */
509 nl_policy_parse(const struct ofpbuf
*msg
, size_t nla_offset
,
510 const struct nl_policy policy
[],
511 struct nlattr
*attrs
[], size_t n_attrs
)
518 for (i
= 0; i
< n_attrs
; i
++) {
521 assert(policy
[i
].type
< N_NL_ATTR_TYPES
);
522 if (policy
[i
].type
!= NL_A_NO_ATTR
523 && policy
[i
].type
!= NL_A_FLAG
524 && !policy
[i
].optional
) {
529 p
= ofpbuf_at(msg
, nla_offset
, 0);
531 VLOG_DBG_RL(&rl
, "missing headers in nl_policy_parse");
534 tail
= ofpbuf_tail(msg
);
537 size_t offset
= (char*)p
- (char*)msg
->data
;
538 struct nlattr
*nla
= p
;
539 size_t len
, aligned_len
;
542 /* Make sure its claimed length is plausible. */
543 if (nla
->nla_len
< NLA_HDRLEN
) {
544 VLOG_DBG_RL(&rl
, "%zu: attr shorter than NLA_HDRLEN (%"PRIu16
")",
545 offset
, nla
->nla_len
);
548 len
= nla
->nla_len
- NLA_HDRLEN
;
549 aligned_len
= NLA_ALIGN(len
);
550 if (aligned_len
> (char*)tail
- (char*)p
) {
551 VLOG_DBG_RL(&rl
, "%zu: attr %"PRIu16
" aligned data len (%zu) "
552 "> bytes left (%tu)",
553 offset
, nl_attr_type(nla
), aligned_len
,
554 (char*)tail
- (char*)p
);
558 type
= nl_attr_type(nla
);
559 if (type
< n_attrs
&& policy
[type
].type
!= NL_A_NO_ATTR
) {
560 const struct nl_policy
*e
= &policy
[type
];
561 size_t min_len
, max_len
;
563 /* Validate length and content. */
564 min_len
= e
->min_len
? e
->min_len
: attr_len_range
[e
->type
][0];
565 max_len
= e
->max_len
? e
->max_len
: attr_len_range
[e
->type
][1];
566 if (len
< min_len
|| len
> max_len
) {
567 VLOG_DBG_RL(&rl
, "%zu: attr %"PRIu16
" length %zu not in "
568 "allowed range %zu...%zu",
569 offset
, type
, len
, min_len
, max_len
);
572 if (e
->type
== NL_A_STRING
) {
573 if (((char *) nla
)[nla
->nla_len
- 1]) {
574 VLOG_DBG_RL(&rl
, "%zu: attr %"PRIu16
" lacks null at end",
578 if (memchr(nla
+ 1, '\0', len
- 1) != NULL
) {
579 VLOG_DBG_RL(&rl
, "%zu: attr %"PRIu16
" has bad length",
584 if (!e
->optional
&& attrs
[type
] == NULL
) {
585 assert(n_required
> 0);
589 VLOG_DBG_RL(&rl
, "%zu: duplicate attr %"PRIu16
, offset
, type
);
593 /* Skip attribute type that we don't care about. */
595 p
= (char*)p
+ NLA_ALIGN(nla
->nla_len
);
598 VLOG_DBG_RL(&rl
, "%zu required attrs missing", n_required
);
604 /* Parses the Netlink attributes within 'nla'. 'policy[i]', for 0 <= i <
605 * n_attrs, specifies how the attribute with nla_type == i is parsed; a pointer
606 * to attribute i is stored in attrs[i]. Returns true if successful, false on
609 nl_parse_nested(const struct nlattr
*nla
, const struct nl_policy policy
[],
610 struct nlattr
*attrs
[], size_t n_attrs
)
614 nl_attr_get_nested(nla
, &buf
);
615 return nl_policy_parse(&buf
, 0, policy
, attrs
, n_attrs
);
618 const struct nlattr
*
619 nl_attr_find__(const struct nlattr
*attrs
, size_t size
, uint16_t type
)
621 const struct nlattr
*nla
;
624 NL_ATTR_FOR_EACH (nla
, left
, attrs
, size
) {
625 if (nl_attr_type (nla
) == type
) {
632 /* Returns the first Netlink attribute within 'buf' with the specified 'type',
633 * skipping a header of 'hdr_len' bytes at the beginning of 'buf'.
635 * This function does not validate the attribute's length. */
636 const struct nlattr
*
637 nl_attr_find(const struct ofpbuf
*buf
, size_t hdr_len
, uint16_t type
)
639 const uint8_t *start
= (const uint8_t *) buf
->data
+ hdr_len
;
640 return nl_attr_find__((const struct nlattr
*) start
, buf
->size
- hdr_len
,
644 /* Returns the first Netlink attribute within 'nla' with the specified
647 * This function does not validate the attribute's length. */
648 const struct nlattr
*
649 nl_attr_find_nested(const struct nlattr
*nla
, uint16_t type
)
651 return nl_attr_find__(nl_attr_get(nla
), nl_attr_get_size(nla
), type
);