aboutsummaryrefslogtreecommitdiffstats
diff options
context:
space:
mode:
Diffstat
-rw-r--r--include/linux/netlink.h24
-rw-r--r--include/net/netlink.h877
-rw-r--r--net/netlink/Makefile2
-rw-r--r--net/netlink/attr.c328
4 files changed, 1229 insertions, 2 deletions
diff --git a/include/linux/netlink.h b/include/linux/netlink.h
index ba25ca874c20..6a2ccf78a356 100644
--- a/include/linux/netlink.h
+++ b/include/linux/netlink.h
@@ -71,7 +71,8 @@ struct nlmsghdr
71 71
72#define NLMSG_ALIGNTO 4 72#define NLMSG_ALIGNTO 4
73#define NLMSG_ALIGN(len) ( ((len)+NLMSG_ALIGNTO-1) & ~(NLMSG_ALIGNTO-1) ) 73#define NLMSG_ALIGN(len) ( ((len)+NLMSG_ALIGNTO-1) & ~(NLMSG_ALIGNTO-1) )
74#define NLMSG_LENGTH(len) ((len)+NLMSG_ALIGN(sizeof(struct nlmsghdr))) 74#define NLMSG_HDRLEN ((int) NLMSG_ALIGN(sizeof(struct nlmsghdr)))
75#define NLMSG_LENGTH(len) ((len)+NLMSG_ALIGN(NLMSG_HDRLEN))
75#define NLMSG_SPACE(len) NLMSG_ALIGN(NLMSG_LENGTH(len)) 76#define NLMSG_SPACE(len) NLMSG_ALIGN(NLMSG_LENGTH(len))
76#define NLMSG_DATA(nlh) ((void*)(((char*)nlh) + NLMSG_LENGTH(0))) 77#define NLMSG_DATA(nlh) ((void*)(((char*)nlh) + NLMSG_LENGTH(0)))
77#define NLMSG_NEXT(nlh,len) ((len) -= NLMSG_ALIGN((nlh)->nlmsg_len), \ 78#define NLMSG_NEXT(nlh,len) ((len) -= NLMSG_ALIGN((nlh)->nlmsg_len), \
@@ -86,6 +87,8 @@ struct nlmsghdr
86#define NLMSG_DONE 0x3 /* End of a dump */ 87#define NLMSG_DONE 0x3 /* End of a dump */
87#define NLMSG_OVERRUN 0x4 /* Data lost */ 88#define NLMSG_OVERRUN 0x4 /* Data lost */
88 89
90#define NLMSG_MIN_TYPE 0x10 /* < 0x10: reserved control messages */
91
89struct nlmsgerr 92struct nlmsgerr
90{ 93{
91 int error; 94 int error;
@@ -108,6 +111,25 @@ enum {
108 NETLINK_CONNECTED, 111 NETLINK_CONNECTED,
109}; 112};
110 113
114/*
115 * <------- NLA_HDRLEN ------> <-- NLA_ALIGN(payload)-->
116 * +---------------------+- - -+- - - - - - - - - -+- - -+
117 * | Header | Pad | Payload | Pad |
118 * | (struct nlattr) | ing | | ing |
119 * +---------------------+- - -+- - - - - - - - - -+- - -+
120 * <-------------- nlattr->nla_len -------------->
121 */
122
123struct nlattr
124{
125 __u16 nla_len;
126 __u16 nla_type;
127};
128
129#define NLA_ALIGNTO 4
130#define NLA_ALIGN(len) (((len) + NLA_ALIGNTO - 1) & ~(NLA_ALIGNTO - 1))
131#define NLA_HDRLEN ((int) NLA_ALIGN(sizeof(struct nlattr)))
132
111#ifdef __KERNEL__ 133#ifdef __KERNEL__
112 134
113#include <linux/capability.h> 135#include <linux/capability.h>
diff --git a/include/net/netlink.h b/include/net/netlink.h
new file mode 100644
index 000000000000..c99e22db9632
--- /dev/null
+++ b/include/net/netlink.h
@@ -0,0 +1,877 @@
1#ifndef __NET_NETLINK_H
2#define __NET_NETLINK_H
3
4#include <linux/types.h>
5#include <linux/netlink.h>
6
7/* ========================================================================
8 * Netlink Messages and Attributes Interface (As Seen On TV)
9 * ------------------------------------------------------------------------
10 * Messages Interface
11 * ------------------------------------------------------------------------
12 *
13 * Message Format:
14 * <--- nlmsg_total_size(payload) --->
15 * <-- nlmsg_msg_size(payload) ->
16 * +----------+- - -+-------------+- - -+-------- - -
17 * | nlmsghdr | Pad | Payload | Pad | nlmsghdr
18 * +----------+- - -+-------------+- - -+-------- - -
19 * nlmsg_data(nlh)---^ ^
20 * nlmsg_next(nlh)-----------------------+
21 *
22 * Payload Format:
23 * <---------------------- nlmsg_len(nlh) --------------------->
24 * <------ hdrlen ------> <- nlmsg_attrlen(nlh, hdrlen) ->
25 * +----------------------+- - -+--------------------------------+
26 * | Family Header | Pad | Attributes |
27 * +----------------------+- - -+--------------------------------+
28 * nlmsg_attrdata(nlh, hdrlen)---^
29 *
30 * Data Structures:
31 * struct nlmsghdr netlink message header
32 *
33 * Message Construction:
34 * nlmsg_new() create a new netlink message
35 * nlmsg_put() add a netlink message to an skb
36 * nlmsg_put_answer() callback based nlmsg_put()
37 * nlmsg_end() finanlize netlink message
38 * nlmsg_cancel() cancel message construction
39 * nlmsg_free() free a netlink message
40 *
41 * Message Sending:
42 * nlmsg_multicast() multicast message to several groups
43 * nlmsg_unicast() unicast a message to a single socket
44 *
45 * Message Length Calculations:
46 * nlmsg_msg_size(payload) length of message w/o padding
47 * nlmsg_total_size(payload) length of message w/ padding
48 * nlmsg_padlen(payload) length of padding at tail
49 *
50 * Message Payload Access:
51 * nlmsg_data(nlh) head of message payload
52 * nlmsg_len(nlh) length of message payload
53 * nlmsg_attrdata(nlh, hdrlen) head of attributes data
54 * nlmsg_attrlen(nlh, hdrlen) length of attributes data
55 *
56 * Message Parsing:
57 * nlmsg_ok(nlh, remaining) does nlh fit into remaining bytes?
58 * nlmsg_next(nlh, remaining) get next netlink message
59 * nlmsg_parse() parse attributes of a message
60 * nlmsg_find_attr() find an attribute in a message
61 * nlmsg_for_each_msg() loop over all messages
62 * nlmsg_validate() validate netlink message incl. attrs
63 * nlmsg_for_each_attr() loop over all attributes
64 *
65 * ------------------------------------------------------------------------
66 * Attributes Interface
67 * ------------------------------------------------------------------------
68 *
69 * Attribute Format:
70 * <------- nla_total_size(payload) ------->
71 * <---- nla_attr_size(payload) ----->
72 * +----------+- - -+- - - - - - - - - +- - -+-------- - -
73 * | Header | Pad | Payload | Pad | Header
74 * +----------+- - -+- - - - - - - - - +- - -+-------- - -
75 * <- nla_len(nla) -> ^
76 * nla_data(nla)----^ |
77 * nla_next(nla)-----------------------------'
78 *
79 * Data Structures:
80 * struct nlattr netlink attribtue header
81 *
82 * Attribute Construction:
83 * nla_reserve(skb, type, len) reserve skb tailroom for an attribute
84 * nla_put(skb, type, len, data) add attribute to skb
85 *
86 * Attribute Construction for Basic Types:
87 * nla_put_u8(skb, type, value) add u8 attribute to skb
88 * nla_put_u16(skb, type, value) add u16 attribute to skb
89 * nla_put_u32(skb, type, value) add u32 attribute to skb
90 * nla_put_u64(skb, type, value) add u64 attribute to skb
91 * nla_put_string(skb, type, str) add string attribute to skb
92 * nla_put_flag(skb, type) add flag attribute to skb
93 * nla_put_msecs(skb, type, jiffies) add msecs attribute to skb
94 *
95 * Exceptions Based Attribute Construction:
96 * NLA_PUT(skb, type, len, data) add attribute to skb
97 * NLA_PUT_U8(skb, type, value) add u8 attribute to skb
98 * NLA_PUT_U16(skb, type, value) add u16 attribute to skb
99 * NLA_PUT_U32(skb, type, value) add u32 attribute to skb
100 * NLA_PUT_U64(skb, type, value) add u64 attribute to skb
101 * NLA_PUT_STRING(skb, type, str) add string attribute to skb
102 * NLA_PUT_FLAG(skb, type) add flag attribute to skb
103 * NLA_PUT_MSECS(skb, type, jiffies) add msecs attribute to skb
104 *
105 * The meaning of these functions is equal to their lower case
106 * variants but they jump to the label nla_put_failure in case
107 * of a failure.
108 *
109 * Nested Attributes Construction:
110 * nla_nest_start(skb, type) start a nested attribute
111 * nla_nest_end(skb, nla) finalize a nested attribute
112 * nla_nest_cancel(skb, nla) cancel nested attribute construction
113 *
114 * Attribute Length Calculations:
115 * nla_attr_size(payload) length of attribute w/o padding
116 * nla_total_size(payload) length of attribute w/ padding
117 * nla_padlen(payload) length of padding
118 *
119 * Attribute Payload Access:
120 * nla_data(nla) head of attribute payload
121 * nla_len(nla) length of attribute payload
122 *
123 * Attribute Payload Access for Basic Types:
124 * nla_get_u8(nla) get payload for a u8 attribute
125 * nla_get_u16(nla) get payload for a u16 attribute
126 * nla_get_u32(nla) get payload for a u32 attribute
127 * nla_get_u64(nla) get payload for a u64 attribute
128 * nla_get_flag(nla) return 1 if flag is true
129 * nla_get_msecs(nla) get payload for a msecs attribute
130 *
131 * Attribute Misc:
132 * nla_memcpy(dest, nla, count) copy attribute into memory
133 * nla_memcmp(nla, data, size) compare attribute with memory area
134 * nla_strlcpy(dst, nla, size) copy attribute to a sized string
135 * nla_strcmp(nla, str) compare attribute with string
136 *
137 * Attribute Parsing:
138 * nla_ok(nla, remaining) does nla fit into remaining bytes?
139 * nla_next(nla, remaining) get next netlink attribute
140 * nla_validate() validate a stream of attributes
141 * nla_find() find attribute in stream of attributes
142 * nla_parse() parse and validate stream of attrs
143 * nla_parse_nested() parse nested attribuets
144 * nla_for_each_attr() loop over all attributes
145 *=========================================================================
146 */
147
148 /**
149 * Standard attribute types to specify validation policy
150 */
151enum {
152 NLA_UNSPEC,
153 NLA_U8,
154 NLA_U16,
155 NLA_U32,
156 NLA_U64,
157 NLA_STRING,
158 NLA_FLAG,
159 NLA_MSECS,
160 NLA_NESTED,
161 __NLA_TYPE_MAX,
162};
163
164#define NLA_TYPE_MAX (__NLA_TYPE_MAX - 1)
165
166/**
167 * struct nla_policy - attribute validation policy
168 * @type: Type of attribute or NLA_UNSPEC
169 * @minlen: Minimal length of payload required to be available
170 *
171 * Policies are defined as arrays of this struct, the array must be
172 * accessible by attribute type up to the highest identifier to be expected.
173 *
174 * Example:
175 * static struct nla_policy my_policy[ATTR_MAX+1] __read_mostly = {
176 * [ATTR_FOO] = { .type = NLA_U16 },
177 * [ATTR_BAR] = { .type = NLA_STRING },
178 * [ATTR_BAZ] = { .minlen = sizeof(struct mystruct) },
179 * };
180 */
181struct nla_policy {
182 u16 type;
183 u16 minlen;
184};
185
186extern int nla_validate(struct nlattr *head, int len, int maxtype,
187 struct nla_policy *policy);
188extern int nla_parse(struct nlattr *tb[], int maxtype,
189 struct nlattr *head, int len,
190 struct nla_policy *policy);
191extern struct nlattr * nla_find(struct nlattr *head, int len, int attrtype);
192extern size_t nla_strlcpy(char *dst, const struct nlattr *nla,
193 size_t dstsize);
194extern int nla_memcpy(void *dest, struct nlattr *src, int count);
195extern int nla_memcmp(const struct nlattr *nla, const void *data,
196 size_t size);
197extern int nla_strcmp(const struct nlattr *nla, const char *str);
198extern struct nlattr * __nla_reserve(struct sk_buff *skb, int attrtype,
199 int attrlen);
200extern struct nlattr * nla_reserve(struct sk_buff *skb, int attrtype,
201 int attrlen);
202extern void __nla_put(struct sk_buff *skb, int attrtype,
203 int attrlen, const void *data);
204extern int nla_put(struct sk_buff *skb, int attrtype,
205 int attrlen, const void *data);
206
207/**************************************************************************
208 * Netlink Messages
209 **************************************************************************/
210
211/**
212 * nlmsg_msg_size - length of netlink message not including padding
213 * @payload: length of message payload
214 */
215static inline int nlmsg_msg_size(int payload)
216{
217 return NLMSG_HDRLEN + payload;
218}
219
220/**
221 * nlmsg_total_size - length of netlink message including padding
222 * @payload: length of message payload
223 */
224static inline int nlmsg_total_size(int payload)
225{
226 return NLMSG_ALIGN(nlmsg_msg_size(payload));
227}
228
229/**
230 * nlmsg_padlen - length of padding at the message's tail
231 * @payload: length of message payload
232 */
233static inline int nlmsg_padlen(int payload)
234{
235 return nlmsg_total_size(payload) - nlmsg_msg_size(payload);
236}
237
238/**
239 * nlmsg_data - head of message payload
240 * @nlh: netlink messsage header
241 */
242static inline void *nlmsg_data(const struct nlmsghdr *nlh)
243{
244 return (unsigned char *) nlh + NLMSG_HDRLEN;
245}
246
247/**
248 * nlmsg_len - length of message payload
249 * @nlh: netlink message header
250 */
251static inline int nlmsg_len(const struct nlmsghdr *nlh)
252{
253 return nlh->nlmsg_len - NLMSG_HDRLEN;
254}
255
256/**
257 * nlmsg_attrdata - head of attributes data
258 * @nlh: netlink message header
259 * @hdrlen: length of family specific header
260 */
261static inline struct nlattr *nlmsg_attrdata(const struct nlmsghdr *nlh,
262 int hdrlen)
263{
264 unsigned char *data = nlmsg_data(nlh);
265 return (struct nlattr *) (data + NLMSG_ALIGN(hdrlen));
266}
267
268/**
269 * nlmsg_attrlen - length of attributes data
270 * @nlh: netlink message header
271 * @hdrlen: length of family specific header
272 */
273static inline int nlmsg_attrlen(const struct nlmsghdr *nlh, int hdrlen)
274{
275 return nlmsg_len(nlh) - NLMSG_ALIGN(hdrlen);
276}
277
278/**
279 * nlmsg_ok - check if the netlink message fits into the remaining bytes
280 * @nlh: netlink message header
281 * @remaining: number of bytes remaining in message stream
282 */
283static inline int nlmsg_ok(const struct nlmsghdr *nlh, int remaining)
284{
285 return (remaining >= sizeof(struct nlmsghdr) &&
286 nlh->nlmsg_len >= sizeof(struct nlmsghdr) &&
287 nlh->nlmsg_len <= remaining);
288}
289
290/**
291 * nlmsg_next - next netlink message in message stream
292 * @nlh: netlink message header
293 * @remaining: number of bytes remaining in message stream
294 *
295 * Returns the next netlink message in the message stream and
296 * decrements remaining by the size of the current message.
297 */
298static inline struct nlmsghdr *nlmsg_next(struct nlmsghdr *nlh, int *remaining)
299{
300 int totlen = NLMSG_ALIGN(nlh->nlmsg_len);
301
302 *remaining -= totlen;
303
304 return (struct nlmsghdr *) ((unsigned char *) nlh + totlen);
305}
306
307/**
308 * nlmsg_parse - parse attributes of a netlink message
309 * @nlh: netlink message header
310 * @hdrlen: length of family specific header
311 * @tb: destination array with maxtype+1 elements
312 * @maxtype: maximum attribute type to be expected
313 * @policy: validation policy
314 *
315 * See nla_parse()
316 */
317static inline int nlmsg_parse(struct nlmsghdr *nlh, int hdrlen,
318 struct nlattr *tb[], int maxtype,
319 struct nla_policy *policy)
320{
321 if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
322 return -EINVAL;
323
324 return nla_parse(tb, maxtype, nlmsg_attrdata(nlh, hdrlen),
325 nlmsg_attrlen(nlh, hdrlen), policy);
326}
327
328/**
329 * nlmsg_find_attr - find a specific attribute in a netlink message
330 * @nlh: netlink message header
331 * @hdrlen: length of familiy specific header
332 * @attrtype: type of attribute to look for
333 *
334 * Returns the first attribute which matches the specified type.
335 */
336static inline struct nlattr *nlmsg_find_attr(struct nlmsghdr *nlh,
337 int hdrlen, int attrtype)
338{
339 return nla_find(nlmsg_attrdata(nlh, hdrlen),
340 nlmsg_attrlen(nlh, hdrlen), attrtype);
341}
342
343/**
344 * nlmsg_validate - validate a netlink message including attributes
345 * @nlh: netlinket message header
346 * @hdrlen: length of familiy specific header
347 * @maxtype: maximum attribute type to be expected
348 * @policy: validation policy
349 */
350static inline int nlmsg_validate(struct nlmsghdr *nlh, int hdrlen, int maxtype,
351 struct nla_policy *policy)
352{
353 if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
354 return -EINVAL;
355
356 return nla_validate(nlmsg_attrdata(nlh, hdrlen),
357 nlmsg_attrlen(nlh, hdrlen), maxtype, policy);
358}
359
360/**
361 * nlmsg_for_each_attr - iterate over a stream of attributes
362 * @pos: loop counter, set to current attribute
363 * @nlh: netlink message header
364 * @hdrlen: length of familiy specific header
365 * @rem: initialized to len, holds bytes currently remaining in stream
366 */
367#define nlmsg_for_each_attr(pos, nlh, hdrlen, rem) \
368 nla_for_each_attr(pos, nlmsg_attrdata(nlh, hdrlen), \
369 nlmsg_attrlen(nlh, hdrlen), rem)
370
371#if 0
372/* FIXME: Enable once all users have been converted */
373
374/**
375 * __nlmsg_put - Add a new netlink message to an skb
376 * @skb: socket buffer to store message in
377 * @pid: netlink process id
378 * @seq: sequence number of message
379 * @type: message type
380 * @payload: length of message payload
381 * @flags: message flags
382 *
383 * The caller is responsible to ensure that the skb provides enough
384 * tailroom for both the netlink header and payload.
385 */
386static inline struct nlmsghdr *__nlmsg_put(struct sk_buff *skb, u32 pid,
387 u32 seq, int type, int payload,
388 int flags)
389{
390 struct nlmsghdr *nlh;
391
392 nlh = (struct nlmsghdr *) skb_put(skb, nlmsg_total_size(payload));
393 nlh->nlmsg_type = type;
394 nlh->nlmsg_len = nlmsg_msg_size(payload);
395 nlh->nlmsg_flags = flags;
396 nlh->nlmsg_pid = pid;
397 nlh->nlmsg_seq = seq;
398
399 memset((unsigned char *) nlmsg_data(nlh) + payload, 0,
400 nlmsg_padlen(payload));
401
402 return nlh;
403}
404#endif
405
406/**
407 * nlmsg_put - Add a new netlink message to an skb
408 * @skb: socket buffer to store message in
409 * @pid: netlink process id
410 * @seq: sequence number of message
411 * @type: message type
412 * @payload: length of message payload
413 * @flags: message flags
414 *
415 * Returns NULL if the tailroom of the skb is insufficient to store
416 * the message header and payload.
417 */
418static inline struct nlmsghdr *nlmsg_put(struct sk_buff *skb, u32 pid, u32 seq,
419 int type, int payload, int flags)
420{
421 if (unlikely(skb_tailroom(skb) < nlmsg_total_size(payload)))
422 return NULL;
423
424 return __nlmsg_put(skb, pid, seq, type, payload, flags);
425}
426
427/**
428 * nlmsg_put_answer - Add a new callback based netlink message to an skb
429 * @skb: socket buffer to store message in
430 * @cb: netlink callback
431 * @type: message type
432 * @payload: length of message payload
433 * @flags: message flags
434 *
435 * Returns NULL if the tailroom of the skb is insufficient to store
436 * the message header and payload.
437 */
438static inline struct nlmsghdr *nlmsg_put_answer(struct sk_buff *skb,
439 struct netlink_callback *cb,
440 int type, int payload,
441 int flags)
442{
443 return nlmsg_put(skb, NETLINK_CB(cb->skb).pid, cb->nlh->nlmsg_seq,
444 type, payload, flags);
445}
446
447/**
448 * nlmsg_new - Allocate a new netlink message
449 * @size: maximum size of message
450 *
451 * Use NLMSG_GOODSIZE if size isn't know and you need a good default size.
452 */
453static inline struct sk_buff *nlmsg_new(int size)
454{
455 return alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
456}
457
458/**
459 * nlmsg_end - Finalize a netlink message
460 * @skb: socket buffer the message is stored in
461 * @nlh: netlink message header
462 *
463 * Corrects the netlink message header to include the appeneded
464 * attributes. Only necessary if attributes have been added to
465 * the message.
466 *
467 * Returns the total data length of the skb.
468 */
469static inline int nlmsg_end(struct sk_buff *skb, struct nlmsghdr *nlh)
470{
471 nlh->nlmsg_len = skb->tail - (unsigned char *) nlh;
472
473 return skb->len;
474}
475
476/**
477 * nlmsg_cancel - Cancel construction of a netlink message
478 * @skb: socket buffer the message is stored in
479 * @nlh: netlink message header
480 *
481 * Removes the complete netlink message including all
482 * attributes from the socket buffer again. Returns -1.
483 */
484static inline int nlmsg_cancel(struct sk_buff *skb, struct nlmsghdr *nlh)
485{
486 skb_trim(skb, (unsigned char *) nlh - skb->data);
487
488 return -1;
489}
490
491/**
492 * nlmsg_free - free a netlink message
493 * @skb: socket buffer of netlink message
494 */
495static inline void nlmsg_free(struct sk_buff *skb)
496{
497 kfree_skb(skb);
498}
499
500/**
501 * nlmsg_multicast - multicast a netlink message
502 * @sk: netlink socket to spread messages to
503 * @skb: netlink message as socket buffer
504 * @pid: own netlink pid to avoid sending to yourself
505 * @group: multicast group id
506 */
507static inline int nlmsg_multicast(struct sock *sk, struct sk_buff *skb,
508 u32 pid, unsigned int group)
509{
510 int err;
511
512 NETLINK_CB(skb).dst_group = group;
513
514 err = netlink_broadcast(sk, skb, pid, group, GFP_KERNEL);
515 if (err > 0)
516 err = 0;
517
518 return err;
519}
520
521/**
522 * nlmsg_unicast - unicast a netlink message
523 * @sk: netlink socket to spread message to
524 * @skb: netlink message as socket buffer
525 * @pid: netlink pid of the destination socket
526 */
527static inline int nlmsg_unicast(struct sock *sk, struct sk_buff *skb, u32 pid)
528{
529 int err;
530
531 err = netlink_unicast(sk, skb, pid, MSG_DONTWAIT);
532 if (err > 0)
533 err = 0;
534
535 return err;
536}
537
538/**
539 * nlmsg_for_each_msg - iterate over a stream of messages
540 * @pos: loop counter, set to current message
541 * @head: head of message stream
542 * @len: length of message stream
543 * @rem: initialized to len, holds bytes currently remaining in stream
544 */
545#define nlmsg_for_each_msg(pos, head, len, rem) \
546 for (pos = head, rem = len; \
547 nlmsg_ok(pos, rem); \
548 pos = nlmsg_next(pos, &(rem)))
549
550/**************************************************************************
551 * Netlink Attributes
552 **************************************************************************/
553
554/**
555 * nla_attr_size - length of attribute not including padding
556 * @payload: length of payload
557 */
558static inline int nla_attr_size(int payload)
559{
560 return NLA_HDRLEN + payload;
561}
562
563/**
564 * nla_total_size - total length of attribute including padding
565 * @payload: length of payload
566 */
567static inline int nla_total_size(int payload)
568{
569 return NLA_ALIGN(nla_attr_size(payload));
570}
571
572/**
573 * nla_padlen - length of padding at the tail of attribute
574 * @payload: length of payload
575 */
576static inline int nla_padlen(int payload)
577{
578 return nla_total_size(payload) - nla_attr_size(payload);
579}
580
581/**
582 * nla_data - head of payload
583 * @nla: netlink attribute
584 */
585static inline void *nla_data(const struct nlattr *nla)
586{
587 return (char *) nla + NLA_HDRLEN;
588}
589
590/**
591 * nla_len - length of payload
592 * @nla: netlink attribute
593 */
594static inline int nla_len(const struct nlattr *nla)
595{
596 return nla->nla_len - NLA_HDRLEN;
597}
598
599/**
600 * nla_ok - check if the netlink attribute fits into the remaining bytes
601 * @nla: netlink attribute
602 * @remaining: number of bytes remaining in attribute stream
603 */
604static inline int nla_ok(const struct nlattr *nla, int remaining)
605{
606 return remaining >= sizeof(*nla) &&
607 nla->nla_len >= sizeof(*nla) &&
608 nla->nla_len <= remaining;
609}
610
611/**
612 * nla_next - next netlink attribte in attribute stream
613 * @nla: netlink attribute
614 * @remaining: number of bytes remaining in attribute stream
615 *
616 * Returns the next netlink attribute in the attribute stream and
617 * decrements remaining by the size of the current attribute.
618 */
619static inline struct nlattr *nla_next(const struct nlattr *nla, int *remaining)
620{
621 int totlen = NLA_ALIGN(nla->nla_len);
622
623 *remaining -= totlen;
624 return (struct nlattr *) ((char *) nla + totlen);
625}
626
627/**
628 * nla_parse_nested - parse nested attributes
629 * @tb: destination array with maxtype+1 elements
630 * @maxtype: maximum attribute type to be expected
631 * @nla: attribute containing the nested attributes
632 * @policy: validation policy
633 *
634 * See nla_parse()
635 */
636static inline int nla_parse_nested(struct nlattr *tb[], int maxtype,
637 struct nlattr *nla,
638 struct nla_policy *policy)
639{
640 return nla_parse(tb, maxtype, nla_data(nla), nla_len(nla), policy);
641}
642/**
643 * nla_put_u8 - Add a u16 netlink attribute to a socket buffer
644 * @skb: socket buffer to add attribute to
645 * @attrtype: attribute type
646 * @value: numeric value
647 */
648static inline int nla_put_u8(struct sk_buff *skb, int attrtype, u8 value)
649{
650 return nla_put(skb, attrtype, sizeof(u8), &value);
651}
652
653/**
654 * nla_put_u16 - Add a u16 netlink attribute to a socket buffer
655 * @skb: socket buffer to add attribute to
656 * @attrtype: attribute type
657 * @value: numeric value
658 */
659static inline int nla_put_u16(struct sk_buff *skb, int attrtype, u16 value)
660{
661 return nla_put(skb, attrtype, sizeof(u16), &value);
662}
663
664/**
665 * nla_put_u32 - Add a u32 netlink attribute to a socket buffer
666 * @skb: socket buffer to add attribute to
667 * @attrtype: attribute type
668 * @value: numeric value
669 */
670static inline int nla_put_u32(struct sk_buff *skb, int attrtype, u32 value)
671{
672 return nla_put(skb, attrtype, sizeof(u32), &value);
673}
674
675/**
676 * nla_put_64 - Add a u64 netlink attribute to a socket buffer
677 * @skb: socket buffer to add attribute to
678 * @attrtype: attribute type
679 * @value: numeric value
680 */
681static inline int nla_put_u64(struct sk_buff *skb, int attrtype, u64 value)
682{
683 return nla_put(skb, attrtype, sizeof(u64), &value);
684}
685
686/**
687 * nla_put_string - Add a string netlink attribute to a socket buffer
688 * @skb: socket buffer to add attribute to
689 * @attrtype: attribute type
690 * @str: NUL terminated string
691 */
692static inline int nla_put_string(struct sk_buff *skb, int attrtype,
693 const char *str)
694{
695 return nla_put(skb, attrtype, strlen(str) + 1, str);
696}
697
698/**
699 * nla_put_flag - Add a flag netlink attribute to a socket buffer
700 * @skb: socket buffer to add attribute to
701 * @attrtype: attribute type
702 */
703static inline int nla_put_flag(struct sk_buff *skb, int attrtype)
704{
705 return nla_put(skb, attrtype, 0, NULL);
706}
707
708/**
709 * nla_put_msecs - Add a msecs netlink attribute to a socket buffer
710 * @skb: socket buffer to add attribute to
711 * @attrtype: attribute type
712 * @jiffies: number of msecs in jiffies
713 */
714static inline int nla_put_msecs(struct sk_buff *skb, int attrtype,
715 unsigned long jiffies)
716{
717 u64 tmp = jiffies_to_msecs(jiffies);
718 return nla_put(skb, attrtype, sizeof(u64), &tmp);
719}
720
721#define NLA_PUT(skb, attrtype, attrlen, data) \
722 do { \
723 if (nla_put(skb, attrtype, attrlen, data) < 0) \
724 goto nla_put_failure; \
725 } while(0)
726
727#define NLA_PUT_TYPE(skb, type, attrtype, value) \
728 do { \
729 type __tmp = value; \
730 NLA_PUT(skb, attrtype, sizeof(type), &__tmp); \
731 } while(0)
732
733#define NLA_PUT_U8(skb, attrtype, value) \
734 NLA_PUT_TYPE(skb, u8, attrtype, value)
735
736#define NLA_PUT_U16(skb, attrtype, value) \
737 NLA_PUT_TYPE(skb, u16, attrtype, value)
738
739#define NLA_PUT_U32(skb, attrtype, value) \
740 NLA_PUT_TYPE(skb, u32, attrtype, value)
741
742#define NLA_PUT_U64(skb, attrtype, value) \
743 NLA_PUT_TYPE(skb, u64, attrtype, value)
744
745#define NLA_PUT_STRING(skb, attrtype, value) \
746 NLA_PUT(skb, attrtype, strlen(value) + 1, value)
747
748#define NLA_PUT_FLAG(skb, attrtype, value) \
749 NLA_PUT(skb, attrtype, 0, NULL)
750
751#define NLA_PUT_MSECS(skb, attrtype, jiffies) \
752 NLA_PUT_U64(skb, attrtype, jiffies_to_msecs(jiffies))
753
754/**
755 * nla_get_u32 - return payload of u32 attribute
756 * @nla: u32 netlink attribute
757 */
758static inline u32 nla_get_u32(struct nlattr *nla)
759{
760 return *(u32 *) nla_data(nla);
761}
762
763/**
764 * nla_get_u16 - return payload of u16 attribute
765 * @nla: u16 netlink attribute
766 */
767static inline u16 nla_get_u16(struct nlattr *nla)
768{
769 return *(u16 *) nla_data(nla);
770}
771
772/**
773 * nla_get_u8 - return payload of u8 attribute
774 * @nla: u8 netlink attribute
775 */
776static inline u8 nla_get_u8(struct nlattr *nla)
777{
778 return *(u8 *) nla_data(nla);
779}
780
781/**
782 * nla_get_u64 - return payload of u64 attribute
783 * @nla: u64 netlink attribute
784 */
785static inline u64 nla_get_u64(struct nlattr *nla)
786{
787 u64 tmp;
788
789 nla_memcpy(&tmp, nla, sizeof(tmp));
790
791 return tmp;
792}
793
794/**
795 * nla_get_flag - return payload of flag attribute
796 * @nla: flag netlink attribute
797 */
798static inline int nla_get_flag(struct nlattr *nla)
799{
800 return !!nla;
801}
802
803/**
804 * nla_get_msecs - return payload of msecs attribute
805 * @nla: msecs netlink attribute
806 *
807 * Returns the number of milliseconds in jiffies.
808 */
809static inline unsigned long nla_get_msecs(struct nlattr *nla)
810{
811 u64 msecs = nla_get_u64(nla);
812
813 return msecs_to_jiffies((unsigned long) msecs);
814}
815
816/**
817 * nla_nest_start - Start a new level of nested attributes
818 * @skb: socket buffer to add attributes to
819 * @attrtype: attribute type of container
820 *
821 * Returns the container attribute
822 */
823static inline struct nlattr *nla_nest_start(struct sk_buff *skb, int attrtype)
824{
825 struct nlattr *start = (struct nlattr *) skb->tail;
826
827 if (nla_put(skb, attrtype, 0, NULL) < 0)
828 return NULL;
829
830 return start;
831}
832
833/**
834 * nla_nest_end - Finalize nesting of attributes
835 * @skb: socket buffer the attribtues are stored in
836 * @start: container attribute
837 *
838 * Corrects the container attribute header to include the all
839 * appeneded attributes.
840 *
841 * Returns the total data length of the skb.
842 */
843static inline int nla_nest_end(struct sk_buff *skb, struct nlattr *start)
844{
845 start->nla_len = skb->tail - (unsigned char *) start;
846 return skb->len;
847}
848
849/**
850 * nla_nest_cancel - Cancel nesting of attributes
851 * @skb: socket buffer the message is stored in
852 * @start: container attribute
853 *
854 * Removes the container attribute and including all nested
855 * attributes. Returns -1.
856 */
857static inline int nla_nest_cancel(struct sk_buff *skb, struct nlattr *start)
858{
859 if (start)
860 skb_trim(skb, (unsigned char *) start - skb->data);
861
862 return -1;
863}
864
865/**
866 * nla_for_each_attr - iterate over a stream of attributes
867 * @pos: loop counter, set to current attribute
868 * @head: head of attribute stream
869 * @len: length of attribute stream
870 * @rem: initialized to len, holds bytes currently remaining in stream
871 */
872#define nla_for_each_attr(pos, head, len, rem) \
873 for (pos = head, rem = len; \
874 nla_ok(pos, rem); \
875 pos = nla_next(pos, &(rem)))
876
877#endif
diff --git a/net/netlink/Makefile b/net/netlink/Makefile
index 39d9c2dcd03c..68179015bd39 100644
--- a/net/netlink/Makefile
+++ b/net/netlink/Makefile
@@ -2,4 +2,4 @@
2# Makefile for the netlink driver. 2# Makefile for the netlink driver.
3# 3#
4 4
5obj-y := af_netlink.o 5obj-y := af_netlink.o attr.o
diff --git a/net/netlink/attr.c b/net/netlink/attr.c
new file mode 100644
index 000000000000..fffef4ab276f
--- /dev/null
+++ b/net/netlink/attr.c
@@ -0,0 +1,328 @@
1/*
2 * NETLINK Netlink attributes
3 *
4 * Authors: Thomas Graf <tgraf@suug.ch>
5 * Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
6 */
7
8#include <linux/config.h>
9#include <linux/module.h>
10#include <linux/kernel.h>
11#include <linux/errno.h>
12#include <linux/jiffies.h>
13#include <linux/netdevice.h>
14#include <linux/skbuff.h>
15#include <linux/string.h>
16#include <linux/types.h>
17#include <net/netlink.h>
18
19static u16 nla_attr_minlen[NLA_TYPE_MAX+1] __read_mostly = {
20 [NLA_U8] = sizeof(u8),
21 [NLA_U16] = sizeof(u16),
22 [NLA_U32] = sizeof(u32),
23 [NLA_U64] = sizeof(u64),
24 [NLA_STRING] = 1,
25 [NLA_NESTED] = NLA_HDRLEN,
26};
27
28static int validate_nla(struct nlattr *nla, int maxtype,
29 struct nla_policy *policy)
30{
31 struct nla_policy *pt;
32 int minlen = 0;
33
34 if (nla->nla_type <= 0 || nla->nla_type > maxtype)
35 return 0;
36
37 pt = &policy[nla->nla_type];
38
39 BUG_ON(pt->type > NLA_TYPE_MAX);
40
41 if (pt->minlen)
42 minlen = pt->minlen;
43 else if (pt->type != NLA_UNSPEC)
44 minlen = nla_attr_minlen[pt->type];
45
46 if (pt->type == NLA_FLAG && nla_len(nla) > 0)
47 return -ERANGE;
48
49 if (nla_len(nla) < minlen)
50 return -ERANGE;
51
52 return 0;
53}
54
55/**
56 * nla_validate - Validate a stream of attributes
57 * @head: head of attribute stream
58 * @len: length of attribute stream
59 * @maxtype: maximum attribute type to be expected
60 * @policy: validation policy
61 *
62 * Validates all attributes in the specified attribute stream against the
63 * specified policy. Attributes with a type exceeding maxtype will be
64 * ignored. See documenation of struct nla_policy for more details.
65 *
66 * Returns 0 on success or a negative error code.
67 */
68int nla_validate(struct nlattr *head, int len, int maxtype,
69 struct nla_policy *policy)
70{
71 struct nlattr *nla;
72 int rem, err;
73
74 nla_for_each_attr(nla, head, len, rem) {
75 err = validate_nla(nla, maxtype, policy);
76 if (err < 0)
77 goto errout;
78 }
79
80 err = 0;
81errout:
82 return err;
83}
84
85/**
86 * nla_parse - Parse a stream of attributes into a tb buffer
87 * @tb: destination array with maxtype+1 elements
88 * @maxtype: maximum attribute type to be expected
89 * @head: head of attribute stream
90 * @len: length of attribute stream
91 *
92 * Parses a stream of attributes and stores a pointer to each attribute in
93 * the tb array accessable via the attribute type. Attributes with a type
94 * exceeding maxtype will be silently ignored for backwards compatibility
95 * reasons. policy may be set to NULL if no validation is required.
96 *
97 * Returns 0 on success or a negative error code.
98 */
99int nla_parse(struct nlattr *tb[], int maxtype, struct nlattr *head, int len,
100 struct nla_policy *policy)
101{
102 struct nlattr *nla;
103 int rem, err;
104
105 memset(tb, 0, sizeof(struct nlattr *) * (maxtype + 1));
106
107 nla_for_each_attr(nla, head, len, rem) {
108 u16 type = nla->nla_type;
109
110 if (type > 0 && type <= maxtype) {
111 if (policy) {
112 err = validate_nla(nla, maxtype, policy);
113 if (err < 0)
114 goto errout;
115 }
116
117 tb[type] = nla;
118 }
119 }
120
121 if (unlikely(rem > 0))
122 printk(KERN_WARNING "netlink: %d bytes leftover after parsing "
123 "attributes.\n", rem);
124
125 err = 0;
126errout:
127 return err;
128}
129
130/**
131 * nla_find - Find a specific attribute in a stream of attributes
132 * @head: head of attribute stream
133 * @len: length of attribute stream
134 * @attrtype: type of attribute to look for
135 *
136 * Returns the first attribute in the stream matching the specified type.
137 */
138struct nlattr *nla_find(struct nlattr *head, int len, int attrtype)
139{
140 struct nlattr *nla;
141 int rem;
142
143 nla_for_each_attr(nla, head, len, rem)
144 if (nla->nla_type == attrtype)
145 return nla;
146
147 return NULL;
148}
149
150/**
151 * nla_strlcpy - Copy string attribute payload into a sized buffer
152 * @dst: where to copy the string to
153 * @src: attribute to copy the string from
154 * @dstsize: size of destination buffer
155 *
156 * Copies at most dstsize - 1 bytes into the destination buffer.
157 * The result is always a valid NUL-terminated string. Unlike
158 * strlcpy the destination buffer is always padded out.
159 *
160 * Returns the length of the source buffer.
161 */
162size_t nla_strlcpy(char *dst, const struct nlattr *nla, size_t dstsize)
163{
164 size_t srclen = nla_len(nla);
165 char *src = nla_data(nla);
166
167 if (srclen > 0 && src[srclen - 1] == '\0')
168 srclen--;
169
170 if (dstsize > 0) {
171 size_t len = (srclen >= dstsize) ? dstsize - 1 : srclen;
172
173 memset(dst, 0, dstsize);
174 memcpy(dst, src, len);
175 }
176
177 return srclen;
178}
179
180/**
181 * nla_memcpy - Copy a netlink attribute into another memory area
182 * @dest: where to copy to memcpy
183 * @src: netlink attribute to copy from
184 * @count: size of the destination area
185 *
186 * Note: The number of bytes copied is limited by the length of
187 * attribute's payload. memcpy
188 *
189 * Returns the number of bytes copied.
190 */
191int nla_memcpy(void *dest, struct nlattr *src, int count)
192{
193 int minlen = min_t(int, count, nla_len(src));
194
195 memcpy(dest, nla_data(src), minlen);
196
197 return minlen;
198}
199
200/**
201 * nla_memcmp - Compare an attribute with sized memory area
202 * @nla: netlink attribute
203 * @data: memory area
204 * @size: size of memory area
205 */
206int nla_memcmp(const struct nlattr *nla, const void *data,
207 size_t size)
208{
209 int d = nla_len(nla) - size;
210
211 if (d == 0)
212 d = memcmp(nla_data(nla), data, size);
213
214 return d;
215}
216
217/**
218 * nla_strcmp - Compare a string attribute against a string
219 * @nla: netlink string attribute
220 * @str: another string
221 */
222int nla_strcmp(const struct nlattr *nla, const char *str)
223{
224 int len = strlen(str) + 1;
225 int d = nla_len(nla) - len;
226
227 if (d == 0)
228 d = memcmp(nla_data(nla), str, len);
229
230 return d;
231}
232
233/**
234 * __nla_reserve - reserve room for attribute on the skb
235 * @skb: socket buffer to reserve room on
236 * @attrtype: attribute type
237 * @attrlen: length of attribute payload
238 *
239 * Adds a netlink attribute header to a socket buffer and reserves
240 * room for the payload but does not copy it.
241 *
242 * The caller is responsible to ensure that the skb provides enough
243 * tailroom for the attribute header and payload.
244 */
245struct nlattr *__nla_reserve(struct sk_buff *skb, int attrtype, int attrlen)
246{
247 struct nlattr *nla;
248
249 nla = (struct nlattr *) skb_put(skb, nla_total_size(attrlen));
250 nla->nla_type = attrtype;
251 nla->nla_len = nla_attr_size(attrlen);
252
253 memset((unsigned char *) nla + nla->nla_len, 0, nla_padlen(attrlen));
254
255 return nla;
256}
257
258/**
259 * nla_reserve - reserve room for attribute on the skb
260 * @skb: socket buffer to reserve room on
261 * @attrtype: attribute type
262 * @attrlen: length of attribute payload
263 *
264 * Adds a netlink attribute header to a socket buffer and reserves
265 * room for the payload but does not copy it.
266 *
267 * Returns NULL if the tailroom of the skb is insufficient to store
268 * the attribute header and payload.
269 */
270struct nlattr *nla_reserve(struct sk_buff *skb, int attrtype, int attrlen)
271{
272 if (unlikely(skb_tailroom(skb) < nla_total_size(attrlen)))
273 return NULL;
274
275 return __nla_reserve(skb, attrtype, attrlen);
276}
277
278/**
279 * __nla_put - Add a netlink attribute to a socket buffer
280 * @skb: socket buffer to add attribute to
281 * @attrtype: attribute type
282 * @attrlen: length of attribute payload
283 * @data: head of attribute payload
284 *
285 * The caller is responsible to ensure that the skb provides enough
286 * tailroom for the attribute header and payload.
287 */
288void __nla_put(struct sk_buff *skb, int attrtype, int attrlen,
289 const void *data)
290{
291 struct nlattr *nla;
292
293 nla = __nla_reserve(skb, attrtype, attrlen);
294 memcpy(nla_data(nla), data, attrlen);
295}
296
297
298/**
299 * nla_put - Add a netlink attribute to a socket buffer
300 * @skb: socket buffer to add attribute to
301 * @attrtype: attribute type
302 * @attrlen: length of attribute payload
303 * @data: head of attribute payload
304 *
305 * Returns -1 if the tailroom of the skb is insufficient to store
306 * the attribute header and payload.
307 */
308int nla_put(struct sk_buff *skb, int attrtype, int attrlen, const void *data)
309{
310 if (unlikely(skb_tailroom(skb) < nla_total_size(attrlen)))
311 return -1;
312
313 __nla_put(skb, attrtype, attrlen, data);
314 return 0;
315}
316
317
318EXPORT_SYMBOL(nla_validate);
319EXPORT_SYMBOL(nla_parse);
320EXPORT_SYMBOL(nla_find);
321EXPORT_SYMBOL(nla_strlcpy);
322EXPORT_SYMBOL(__nla_reserve);
323EXPORT_SYMBOL(nla_reserve);
324EXPORT_SYMBOL(__nla_put);
325EXPORT_SYMBOL(nla_put);
326EXPORT_SYMBOL(nla_memcpy);
327EXPORT_SYMBOL(nla_memcmp);
328EXPORT_SYMBOL(nla_strcmp);
generated by cgit v1.2.2 (git 2.25.0) at 2025-10-28 05:51:09 -0400