1 /* SPDX-License-Identifier: GPL-2.0 */
12  * ------------------------------------------------------------------------
14  * ------------------------------------------------------------------------
17  *    <--- nlmsg_total_size(payload)  --->
18  *    <-- nlmsg_msg_size(payload) ->
19  *   +----------+- - -+-------------+- - -+-------- - -
21  *   +----------+- - -+-------------+- - -+-------- - -
22  *   nlmsg_data(nlh)---^                   ^
23  *   nlmsg_next(nlh)-----------------------+
26  *    <---------------------- nlmsg_len(nlh) --------------------->
27  *    <------ hdrlen ------>       <- nlmsg_attrlen(nlh, hdrlen) ->
28  *   +----------------------+- - -+--------------------------------+
30  *   +----------------------+- - -+--------------------------------+
31  *   nlmsg_attrdata(nlh, hdrlen)---^
66  *   nlmsg_find_attr()			find an attribute in a message
74  * ------------------------------------------------------------------------
76  * ------------------------------------------------------------------------
78  * Attribute Format:
79  *    <------- nla_total_size(payload) ------->
80  *    <---- nla_attr_size(payload) ----->
81  *   +----------+- - -+- - - - - - - - - +- - -+-------- - -
83  *   +----------+- - -+- - - - - - - - - +- - -+-------- - -
84  *                     <- nla_len(nla) ->      ^
85  *   nla_data(nla)----^                        |
86  *   nla_next(nla)-----------------------------'
89  *   struct nlattr			netlink attribute header
91  * Attribute Construction:
92  *   nla_reserve(skb, type, len)	reserve room for an attribute
93  *   nla_reserve_nohdr(skb, len)	reserve room for an attribute w/o hdr
94  *   nla_put(skb, type, len, data)	add attribute to skb
95  *   nla_put_nohdr(skb, len, data)	add attribute w/o hdr
98  * Attribute Construction for Basic Types:
99  *   nla_put_u8(skb, type, value)	add u8 attribute to skb
100  *   nla_put_u16(skb, type, value)	add u16 attribute to skb
101  *   nla_put_u32(skb, type, value)	add u32 attribute to skb
103  *                     value, padattr)	add u64 attribute to skb
104  *   nla_put_s8(skb, type, value)	add s8 attribute to skb
105  *   nla_put_s16(skb, type, value)	add s16 attribute to skb
106  *   nla_put_s32(skb, type, value)	add s32 attribute to skb
108  *               padattr)		add s64 attribute to skb
109  *   nla_put_string(skb, type, str)	add string attribute to skb
110  *   nla_put_flag(skb, type)		add flag attribute to skb
112  *                 padattr)		add msecs attribute to skb
113  *   nla_put_in_addr(skb, type, addr)	add IPv4 address attribute to skb
114  *   nla_put_in6_addr(skb, type, addr)	add IPv6 address attribute to skb
117  *   nla_nest_start(skb, type)		start a nested attribute
118  *   nla_nest_end(skb, nla)		finalize a nested attribute
119  *   nla_nest_cancel(skb, nla)		cancel nested attribute construction
121  * Attribute Length Calculations:
122  *   nla_attr_size(payload)		length of attribute w/o padding
123  *   nla_total_size(payload)		length of attribute w/ padding
126  * Attribute Payload Access:
127  *   nla_data(nla)			head of attribute payload
128  *   nla_len(nla)			length of attribute payload
130  * Attribute Payload Access for Basic Types:
131  *   nla_get_uint(nla)			get payload for a uint attribute
132  *   nla_get_sint(nla)			get payload for a sint attribute
133  *   nla_get_u8(nla)			get payload for a u8 attribute
134  *   nla_get_u16(nla)			get payload for a u16 attribute
135  *   nla_get_u32(nla)			get payload for a u32 attribute
136  *   nla_get_u64(nla)			get payload for a u64 attribute
137  *   nla_get_s8(nla)			get payload for a s8 attribute
138  *   nla_get_s16(nla)			get payload for a s16 attribute
139  *   nla_get_s32(nla)			get payload for a s32 attribute
140  *   nla_get_s64(nla)			get payload for a s64 attribute
142  *   nla_get_msecs(nla)			get payload for a msecs attribute
144  * Attribute Misc:
145  *   nla_memcpy(dest, nla, count)	copy attribute into memory
146  *   nla_memcmp(nla, data, size)	compare attribute with memory area
147  *   nla_strscpy(dst, nla, size)	copy attribute to a sized string
148  *   nla_strcmp(nla, str)		compare attribute with string
150  * Attribute Parsing:
152  *   nla_next(nla, remaining)		get next netlink attribute
155  *   nla_find()				find attribute in stream of attributes
156  *   nla_find_nested()			find attribute in nested attributes
165   * Standard attribute types to specify validation policy
193 #define NLA_TYPE_MAX (__NLA_TYPE_MAX - 1)
215  * struct nla_policy - attribute validation policy
216  * @type: Type of attribute or NLA_UNSPEC
217  * @validation_type: type of attribute validation done in addition to
218  *	type-specific validation (e.g. range, function call), see
223  * accessible by attribute type up to the highest identifier to be expected.
229  *    NLA_BINARY           Maximum length of attribute payload
247  *    All other            Minimum length of attribute payload
250  *    NLA_BITFIELD32       This is a 32-bit bitmap/bitselector attribute and
252  *    NLA_REJECT           This attribute is always rejected and `reject_message'
256  *                         also set `len' to the max attribute number. Use the
259  *                         parse, the nested sub-policies.
261  *                         must also set `len' to the max attribute number. Use
266  *                         level down and the attribute types directly in the
282  *                         the value of the integer attribute.
286  *                         of s16 - do that using the NLA_POLICY_FULL_RANGE()
294  *    NLA_U64              If the validation_type field instead is set to
303  *    NLA_S64              If the validation_type field instead is set to
311  *                         integers) of the attribute is enforced.
313  *    All other            Unused - but note that it's a union
316  *    NLA_BINARY           Validation function called for the attribute.
317  *    All other            Unused - but note that it's a union
336 		 * @strict_start_type: first attribute to validate strictly
338 		 * This entry is special, and used for the attribute at index 0
341 		 * starts for any attribute types >= this value, also, strict
350 		 * For completely new families it should be set to 1 so that the
352 		 * it should be set at least when new attributes are added to
353 		 * the enum used by the policy, and be set to the new value that
358 		/* private: use NLA_POLICY_*() to set */
381 	_NLA_POLICY_NESTED(ARRAY_SIZE(policy) - 1, policy)
383 	_NLA_POLICY_NESTED_ARRAY(ARRAY_SIZE(policy) - 1, policy)
469  * struct nl_info - netlink source information
474  * @skip_notify_kernel: Skip selected in-kernel notifications
485  * enum netlink_validation - netlink message/attribute validation levels
486  * @NL_VALIDATE_LIBERAL: Old-style "be liberal" validation, not caring about
489  * @NL_VALIDATE_TRAILING: Reject junk data encountered after attribute parsing.
493  *	This can safely be set by the kernel when the given policy has no
496  * @NL_VALIDATE_STRICT_ATTRS: strict attribute policy parsing (e.g.
498  * @NL_VALIDATE_NESTED: Check that NLA_F_NESTED is set for NLA_NESTED(_ARRAY)
561  * nlmsg_msg_size - length of netlink message not including padding
570  * nlmsg_total_size - length of netlink message including padding
579  * nlmsg_padlen - length of padding at the message's tail
584 	return nlmsg_total_size(payload) - nlmsg_msg_size(payload);  in nlmsg_padlen()
588  * nlmsg_data - head of message payload
597  * nlmsg_len - length of message payload
602 	return nlh->nlmsg_len - NLMSG_HDRLEN;  in nlmsg_len()
606  * nlmsg_attrdata - head of attributes data
618  * nlmsg_attrlen - length of attributes data
624 	return nlmsg_len(nlh) - NLMSG_ALIGN(hdrlen);  in nlmsg_attrlen()
628  * nlmsg_ok - check if the netlink message fits into the remaining bytes
635 		nlh->nlmsg_len >= sizeof(struct nlmsghdr) &&  in nlmsg_ok()
636 		nlh->nlmsg_len <= remaining);  in nlmsg_ok()
640  * nlmsg_next - next netlink message in message stream
650 	int totlen = NLMSG_ALIGN(nlh->nlmsg_len);  in nlmsg_next()
652 	*remaining -= totlen;  in nlmsg_next()
658  * nla_parse - Parse a stream of attributes into a tb buffer
660  * @maxtype: maximum attribute type to be expected
661  * @head: head of attribute stream
662  * @len: length of attribute stream
666  * Parses a stream of attributes and stores a pointer to each attribute in
667  * the tb array accessible via the attribute type. Attributes with a type
683  * nla_parse_deprecated - Parse a stream of attributes into a tb buffer
685  * @maxtype: maximum attribute type to be expected
686  * @head: head of attribute stream
687  * @len: length of attribute stream
691  * Parses a stream of attributes and stores a pointer to each attribute in
692  * the tb array accessible via the attribute type. Attributes with a type
708  * nla_parse_deprecated_strict - Parse a stream of attributes into a tb buffer
710  * @maxtype: maximum attribute type to be expected
711  * @head: head of attribute stream
712  * @len: length of attribute stream
716  * Parses a stream of attributes and stores a pointer to each attribute in
717  * the tb array accessible via the attribute type. Attributes with a type
734  * __nlmsg_parse - parse attributes of a netlink message
738  * @maxtype: maximum attribute type to be expected
751 	if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen)) {  in __nlmsg_parse()
753 		return -EINVAL;  in __nlmsg_parse()
762  * nlmsg_parse - parse attributes of a netlink message
766  * @maxtype: maximum attribute type to be expected
782  * nlmsg_parse_deprecated - parse attributes of a netlink message
786  * @maxtype: maximum attribute type to be expected
802  * nlmsg_parse_deprecated_strict - parse attributes of a netlink message
806  * @maxtype: maximum attribute type to be expected
823  * nlmsg_find_attr - find a specific attribute in a netlink message
826  * @attrtype: type of attribute to look for
828  * Returns the first attribute which matches the specified type.
838  * nla_validate_deprecated - Validate a stream of attributes
839  * @head: head of attribute stream
840  * @len: length of attribute stream
841  * @maxtype: maximum attribute type to be expected
845  * Validates all attributes in the specified attribute stream against the
861  * nla_validate - Validate a stream of attributes
862  * @head: head of attribute stream
863  * @len: length of attribute stream
864  * @maxtype: maximum attribute type to be expected
868  * Validates all attributes in the specified attribute stream against the
883  * nlmsg_validate_deprecated - validate a netlink message including attributes
886  * @maxtype: maximum attribute type to be expected
895 	if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))  in nlmsg_validate_deprecated()
896 		return -EINVAL;  in nlmsg_validate_deprecated()
906  * nlmsg_report - need to report back to application?
913 	return nlh ? !!(nlh->nlmsg_flags & NLM_F_ECHO) : 0;  in nlmsg_report()
917  * nlmsg_seq - return the seq number of netlink message
924 	return nlh ? nlh->nlmsg_seq : 0;  in nlmsg_seq()
928  * nlmsg_for_each_attr - iterate over a stream of attributes
929  * @pos: loop counter, set to current attribute
939  * nlmsg_put - Add a new netlink message to an skb
960  * nlmsg_append - Add more data to a nlmsg in a skb
965  * with multiple fixed-format headers (which is rare).
974 	if (NLMSG_ALIGN(size) - size)  in nlmsg_append()
976 		       NLMSG_ALIGN(size) - size);  in nlmsg_append()
981  * nlmsg_put_answer - Add a new callback based netlink message to an skb
996 	return nlmsg_put(skb, NETLINK_CB(cb->skb).portid, cb->nlh->nlmsg_seq,  in nlmsg_put_answer()
1001  * nlmsg_new - Allocate a new netlink message
1014  * nlmsg_new_large - Allocate a new netlink message with non-contiguous
1018  * The allocated skb is unable to have frag page for shinfo->frags*,
1019  * as the NULL setting for skb->head in netlink_skb_destructor() will
1028  * nlmsg_end - Finalize a netlink message
1038 	nlh->nlmsg_len = skb_tail_pointer(skb) - (unsigned char *)nlh;  in nlmsg_end()
1042  * nlmsg_get_pos - return current position in netlink message
1053  * nlmsg_trim - Trim message to a mark
1062 		WARN_ON((unsigned char *) mark < skb->data);  in nlmsg_trim()
1063 		skb_trim(skb, (unsigned char *) mark - skb->data);  in nlmsg_trim()
1068  * nlmsg_cancel - Cancel construction of a netlink message
1081  * nlmsg_free - free a netlink message
1090  * nlmsg_multicast_filtered - multicast a netlink message with filter function
1120  * nlmsg_multicast - multicast a netlink message
1135  * nlmsg_unicast - unicast a netlink message
1152  * nlmsg_for_each_msg - iterate over a stream of messages
1153  * @pos: loop counter, set to current message
1164  * nl_dump_check_consistent - check if sequence is consistent and advertise if not
1171  * The correct way to use it is to set cb->seq to the generation counter when
1182 	if (cb->prev_seq && cb->seq != cb->prev_seq)  in nl_dump_check_consistent()
1183 		nlh->nlmsg_flags |= NLM_F_DUMP_INTR;  in nl_dump_check_consistent()
1184 	cb->prev_seq = cb->seq;  in nl_dump_check_consistent()
1192  * nla_attr_size - length of attribute not including padding
1201  * nla_total_size - total length of attribute including padding
1210  * nla_padlen - length of padding at the tail of attribute
1215 	return nla_total_size(payload) - nla_attr_size(payload);  in nla_padlen()
1219  * nla_type - attribute type
1220  * @nla: netlink attribute
1224 	return nla->nla_type & NLA_TYPE_MASK;  in nla_type()
1228  * nla_data - head of payload
1229  * @nla: netlink attribute
1237  * nla_len - length of payload
1238  * @nla: netlink attribute
1242 	return nla->nla_len - NLA_HDRLEN;  in nla_len()
1246  * nla_ok - check if the netlink attribute fits into the remaining bytes
1247  * @nla: netlink attribute
1248  * @remaining: number of bytes remaining in attribute stream
1253 	       nla->nla_len >= sizeof(*nla) &&  in nla_ok()
1254 	       nla->nla_len <= remaining;  in nla_ok()
1258  * nla_next - next netlink attribute in attribute stream
1259  * @nla: netlink attribute
1260  * @remaining: number of bytes remaining in attribute stream
1262  * Returns the next netlink attribute in the attribute stream and
1263  * decrements remaining by the size of the current attribute.
1267 	unsigned int totlen = NLA_ALIGN(nla->nla_len);  in nla_next()
1269 	*remaining -= totlen;  in nla_next()
1274  * nla_find_nested - find attribute in a set of nested attributes
1275  * @nla: attribute containing the nested attributes
1276  * @attrtype: type of attribute to look for
1278  * Returns the first attribute which matches the specified type.
1287  * nla_parse_nested - parse nested attributes
1289  * @maxtype: maximum attribute type to be expected
1290  * @nla: attribute containing the nested attributes
1301 	if (!(nla->nla_type & NLA_F_NESTED)) {  in nla_parse_nested()
1303 		return -EINVAL;  in nla_parse_nested()
1311  * nla_parse_nested_deprecated - parse nested attributes
1313  * @maxtype: maximum attribute type to be expected
1314  * @nla: attribute containing the nested attributes
1330  * nla_put_u8 - Add a u8 netlink attribute to a socket buffer
1331  * @skb: socket buffer to add attribute to
1332  * @attrtype: attribute type
1337 	/* temporary variables to work around GCC PR81715 with asan-stack=1 */  in nla_put_u8()
1344  * nla_put_u16 - Add a u16 netlink attribute to a socket buffer
1345  * @skb: socket buffer to add attribute to
1346  * @attrtype: attribute type
1357  * nla_put_be16 - Add a __be16 netlink attribute to a socket buffer
1358  * @skb: socket buffer to add attribute to
1359  * @attrtype: attribute type
1370  * nla_put_net16 - Add 16-bit network byte order netlink attribute to a socket buffer
1371  * @skb: socket buffer to add attribute to
1372  * @attrtype: attribute type
1383  * nla_put_le16 - Add a __le16 netlink attribute to a socket buffer
1384  * @skb: socket buffer to add attribute to
1385  * @attrtype: attribute type
1396  * nla_put_u32 - Add a u32 netlink attribute to a socket buffer
1397  * @skb: socket buffer to add attribute to
1398  * @attrtype: attribute type
1409  * nla_put_uint - Add a variable-size unsigned int to a socket buffer
1410  * @skb: socket buffer to add attribute to
1411  * @attrtype: attribute type
1425  * nla_put_be32 - Add a __be32 netlink attribute to a socket buffer
1426  * @skb: socket buffer to add attribute to
1427  * @attrtype: attribute type
1438  * nla_put_net32 - Add 32-bit network byte order netlink attribute to a socket buffer
1439  * @skb: socket buffer to add attribute to
1440  * @attrtype: attribute type
1451  * nla_put_le32 - Add a __le32 netlink attribute to a socket buffer
1452  * @skb: socket buffer to add attribute to
1453  * @attrtype: attribute type
1464  * nla_put_u64_64bit - Add a u64 netlink attribute to a skb and align it
1465  * @skb: socket buffer to add attribute to
1466  * @attrtype: attribute type
1468  * @padattr: attribute type for the padding
1479  * nla_put_be64 - Add a __be64 netlink attribute to a socket buffer and align it
1480  * @skb: socket buffer to add attribute to
1481  * @attrtype: attribute type
1483  * @padattr: attribute type for the padding
1494  * nla_put_net64 - Add 64-bit network byte order nlattr to a skb and align it
1495  * @skb: socket buffer to add attribute to
1496  * @attrtype: attribute type
1498  * @padattr: attribute type for the padding
1510  * nla_put_le64 - Add a __le64 netlink attribute to a socket buffer and align it
1511  * @skb: socket buffer to add attribute to
1512  * @attrtype: attribute type
1514  * @padattr: attribute type for the padding
1525  * nla_put_s8 - Add a s8 netlink attribute to a socket buffer
1526  * @skb: socket buffer to add attribute to
1527  * @attrtype: attribute type
1538  * nla_put_s16 - Add a s16 netlink attribute to a socket buffer
1539  * @skb: socket buffer to add attribute to
1540  * @attrtype: attribute type
1551  * nla_put_s32 - Add a s32 netlink attribute to a socket buffer
1552  * @skb: socket buffer to add attribute to
1553  * @attrtype: attribute type
1564  * nla_put_s64 - Add a s64 netlink attribute to a socket buffer and align it
1565  * @skb: socket buffer to add attribute to
1566  * @attrtype: attribute type
1568  * @padattr: attribute type for the padding
1579  * nla_put_sint - Add a variable-size signed int to a socket buffer
1580  * @skb: socket buffer to add attribute to
1581  * @attrtype: attribute type
1595  * nla_put_string - Add a string netlink attribute to a socket buffer
1596  * @skb: socket buffer to add attribute to
1597  * @attrtype: attribute type
1607  * nla_put_flag - Add a flag netlink attribute to a socket buffer
1608  * @skb: socket buffer to add attribute to
1609  * @attrtype: attribute type
1617  * nla_put_msecs - Add a msecs netlink attribute to a skb and align it
1618  * @skb: socket buffer to add attribute to
1619  * @attrtype: attribute type
1621  * @padattr: attribute type for the padding
1632  * nla_put_in_addr - Add an IPv4 address netlink attribute to a socket
1634  * @skb: socket buffer to add attribute to
1635  * @attrtype: attribute type
1647  * nla_put_in6_addr - Add an IPv6 address netlink attribute to a socket
1649  * @skb: socket buffer to add attribute to
1650  * @attrtype: attribute type
1660  * nla_put_bitfield32 - Add a bitfield32 netlink attribute to a socket buffer
1661  * @skb: socket buffer to add attribute to
1662  * @attrtype: attribute type
1675  * nla_get_u32 - return payload of u32 attribute
1676  * @nla: u32 netlink attribute
1684  * nla_get_be32 - return payload of __be32 attribute
1685  * @nla: __be32 netlink attribute
1693  * nla_get_le32 - return payload of __le32 attribute
1694  * @nla: __le32 netlink attribute
1702  * nla_get_u16 - return payload of u16 attribute
1703  * @nla: u16 netlink attribute
1711  * nla_get_be16 - return payload of __be16 attribute
1712  * @nla: __be16 netlink attribute
1720  * nla_get_le16 - return payload of __le16 attribute
1721  * @nla: __le16 netlink attribute
1729  * nla_get_u8 - return payload of u8 attribute
1730  * @nla: u8 netlink attribute
1738  * nla_get_u64 - return payload of u64 attribute
1739  * @nla: u64 netlink attribute
1751  * nla_get_uint - return payload of uint attribute
1752  * @nla: uint netlink attribute
1762  * nla_get_be64 - return payload of __be64 attribute
1763  * @nla: __be64 netlink attribute
1775  * nla_get_le64 - return payload of __le64 attribute
1776  * @nla: __le64 netlink attribute
1784  * nla_get_s32 - return payload of s32 attribute
1785  * @nla: s32 netlink attribute
1793  * nla_get_s16 - return payload of s16 attribute
1794  * @nla: s16 netlink attribute
1802  * nla_get_s8 - return payload of s8 attribute
1803  * @nla: s8 netlink attribute
1811  * nla_get_s64 - return payload of s64 attribute
1812  * @nla: s64 netlink attribute
1824  * nla_get_sint - return payload of uint attribute
1825  * @nla: uint netlink attribute
1835  * nla_get_flag - return payload of flag attribute
1836  * @nla: flag netlink attribute
1844  * nla_get_msecs - return payload of msecs attribute
1845  * @nla: msecs netlink attribute
1857  * nla_get_in_addr - return payload of IPv4 address attribute
1858  * @nla: IPv4 address netlink attribute
1866  * nla_get_in6_addr - return payload of IPv6 address attribute
1867  * @nla: IPv6 address netlink attribute
1878  * nla_get_bitfield32 - return payload of 32 bitfield attribute
1879  * @nla: nla_bitfield32 attribute
1890  * nla_memdup - duplicate attribute memory (kmemdup)
1891  * @src: netlink attribute to duplicate from
1900  * nla_nest_start_noflag - Start a new level of nested attributes
1902  * @attrtype: attribute type of container
1908  * Returns the container attribute or NULL on error
1922  * nla_nest_start - Start a new level of nested attributes, with NLA_F_NESTED
1924  * @attrtype: attribute type of container
1926  * Unlike nla_nest_start_noflag(), mark the nest attribute with NLA_F_NESTED
1929  * Returns the container attribute or NULL on error
1937  * nla_nest_end - Finalize nesting of attributes
1939  * @start: container attribute
1941  * Corrects the container attribute header to include the all
1948 	start->nla_len = skb_tail_pointer(skb) - (unsigned char *)start;  in nla_nest_end()
1949 	return skb->len;  in nla_nest_end()
1953  * nla_nest_cancel - Cancel nesting of attributes
1955  * @start: container attribute
1957  * Removes the container attribute and including all nested
1958  * attributes. Returns -EMSGSIZE
1966  * __nla_validate_nested - Validate a stream of nested attributes
1967  * @start: container attribute
1968  * @maxtype: maximum attribute type to be expected
1973  * Validates all attributes in the nested attribute stream against the
2007  * nla_need_padding_for_64bit - test 64-bit alignment of the next attribute
2010  * Return true if padding is needed to align the next attribute (nla_data()) to
2011  * a 64-bit aligned area.
2017 	 * if the skb->data _is_ aligned.  A NOP attribute, plus  in nla_need_padding_for_64bit()
2018 	 * nlattr header for next attribute, will make nla_data()  in nla_need_padding_for_64bit()
2019 	 * 8-byte aligned.  in nla_need_padding_for_64bit()
2028  * nla_align_64bit - 64-bit align the nla_data() of next attribute
2030  * @padattr: attribute type for the padding
2032  * Conditionally emit a padding netlink attribute in order to make
2033  * the next attribute we emit have a 64-bit aligned nla_data() area.
2043 		return -EMSGSIZE;  in nla_align_64bit()
2049  * nla_total_size_64bit - total length of attribute including padding
2062  * nla_for_each_attr - iterate over a stream of attributes
2063  * @pos: loop counter, set to current attribute
2064  * @head: head of attribute stream
2065  * @len: length of attribute stream
2074  * nla_for_each_nested - iterate over nested attributes
2075  * @pos: loop counter, set to current attribute
2076  * @nla: attribute containing the nested attributes
2083  * nla_is_last - Test if attribute is last in stream
2084  * @nla: attribute to test
2089 	return nla->nla_len == rem;  in nla_is_last()