1 /* SPDX-License-Identifier: GPL-2.0 */
11  *         Netlink Messages and Attributes Interface (As Seen On TV)
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  *   +----------------------+- - -+--------------------------------+
29  *   |     Family Header    | Pad |           Attributes           |
30  *   +----------------------+- - -+--------------------------------+
31  *   nlmsg_attrdata(nlh, hdrlen)---^
60  *   nlmsg_attrdata(nlh, hdrlen)	head of attributes data
61  *   nlmsg_attrlen(nlh, hdrlen)		length of attributes data
66  *   nlmsg_parse()			parse attributes of a message
70  *   nlmsg_for_each_attr()		loop over all attributes
75  * ------------------------------------------------------------------------
76  *                          Attributes Interface
77  * ------------------------------------------------------------------------
80  *    <------- nla_total_size(payload) ------->
81  *    <---- nla_attr_size(payload) ----->
82  *   +----------+- - -+- - - - - - - - - +- - -+-------- - -
84  *   +----------+- - -+- - - - - - - - - +- - -+-------- - -
85  *                     <- nla_len(nla) ->      ^
86  *   nla_data(nla)----^                        |
87  *   nla_next(nla)-----------------------------'
117  * Nested Attributes Construction:
118  *   nla_nest_start(skb, type)		start a nested attribute
119  *   nla_nest_end(skb, nla)		finalize a nested attribute
120  *   nla_nest_cancel(skb, nla)		cancel nested attribute construction
156  *   nla_validate()			validate a stream of attributes
157  *   nla_validate_nested()		validate a stream of nested attributes
158  *   nla_find()				find attribute in stream of attributes
159  *   nla_find_nested()			find attribute in nested attributes
161  *   nla_parse_nested()			parse nested attributes
162  *   nla_for_each_attr()		loop over all attributes
163  *   nla_for_each_attr_type()		loop over all attributes with the
165  *   nla_for_each_nested()		loop over the nested attributes
166  *   nla_for_each_nested_type()		loop over the nested attributes with
200 #define NLA_TYPE_MAX (__NLA_TYPE_MAX - 1)
222  * struct nla_policy - attribute validation policy
225  *	type-specific validation (e.g. range, function call), see
240  *                         nested header (or empty); len field is used if
242  *                         number in the nested policy.
257  *    NLA_BITFIELD32       This is a 32-bit bitmap/bitselector attribute and
262  *    NLA_NESTED           `nested_policy' to a nested policy to validate, must
266  *                         parse, the nested sub-policies.
267  *    NLA_NESTED_ARRAY     `nested_policy' points to a nested policy to validate,
271  *                         NLA_NESTED has the nested attributes directly inside
272  *                         while an array has the nested attributes at another
293  *                         of s16 - do that using the NLA_POLICY_FULL_RANGE()
320  *    All other            Unused - but note that it's a union
324  *    All other            Unused - but note that it's a union
358 		 * validation is enforced for all attributes. For existing ones
359 		 * it should be set at least when new attributes are added to
388 	_NLA_POLICY_NESTED(ARRAY_SIZE(policy) - 1, policy)
390 	_NLA_POLICY_NESTED_ARRAY(ARRAY_SIZE(policy) - 1, policy)
477  * struct nl_info - netlink source information
482  * @skip_notify_kernel: Skip selected in-kernel notifications
493  * enum netlink_validation - netlink message/attribute validation levels
494  * @NL_VALIDATE_LIBERAL: Old-style "be liberal" validation, not caring about
495  *	extra data at the end of the message, attributes being longer than
496  *	they should be, or unknown attributes being present.
498  * @NL_VALIDATE_MAXTYPE: Reject attributes > max type; Together with _TRAILING
500  * @NL_VALIDATE_UNSPEC: Reject attributes with NLA_UNSPEC in the policy.
569  * nlmsg_msg_size - length of netlink message not including padding
578  * nlmsg_total_size - length of netlink message including padding
587  * nlmsg_padlen - length of padding at the message's tail
592 	return nlmsg_total_size(payload) - nlmsg_msg_size(payload);  in nlmsg_padlen()
596  * nlmsg_data - head of message payload
605  * nlmsg_len - length of message payload
610 	return nlh->nlmsg_len - NLMSG_HDRLEN;  in nlmsg_len()
614  * nlmsg_attrdata - head of attributes data
626  * nlmsg_attrlen - length of attributes data
632 	return nlmsg_len(nlh) - NLMSG_ALIGN(hdrlen);  in nlmsg_attrlen()
636  * nlmsg_ok - check if the netlink message fits into the remaining bytes
643 		nlh->nlmsg_len >= sizeof(struct nlmsghdr) &&  in nlmsg_ok()
644 		nlh->nlmsg_len <= remaining);  in nlmsg_ok()
648  * nlmsg_next - next netlink message in message stream
658 	int totlen = NLMSG_ALIGN(nlh->nlmsg_len);  in nlmsg_next()
660 	*remaining -= totlen;  in nlmsg_next()
666  * nla_parse - Parse a stream of attributes into a tb buffer
674  * Parses a stream of attributes and stores a pointer to each attribute in
675  * the tb array accessible via the attribute type. Attributes with a type
676  * exceeding maxtype will be rejected, policy must be specified, attributes
691  * nla_parse_deprecated - Parse a stream of attributes into a tb buffer
699  * Parses a stream of attributes and stores a pointer to each attribute in
700  * the tb array accessible via the attribute type. Attributes with a type
701  * exceeding maxtype will be ignored and attributes from the policy are not
702  * always strictly validated (only for new attributes).
716  * nla_parse_deprecated_strict - Parse a stream of attributes into a tb buffer
724  * Parses a stream of attributes and stores a pointer to each attribute in
725  * the tb array accessible via the attribute type. Attributes with a type
727  * policy is not completely strictly validated (only for new attributes).
742  * __nlmsg_parse - parse attributes of a netlink message
759 	if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen)) {  in __nlmsg_parse()
761 		return -EINVAL;  in __nlmsg_parse()
770  * nlmsg_parse - parse attributes of a netlink message
790  * nlmsg_parse_deprecated - parse attributes of a netlink message
810  * nlmsg_parse_deprecated_strict - parse attributes of a netlink message
831  * nlmsg_find_attr - find a specific attribute in a netlink message
846  * nla_validate_deprecated - Validate a stream of attributes
853  * Validates all attributes in the specified attribute stream against the
869  * nla_validate - Validate a stream of attributes
876  * Validates all attributes in the specified attribute stream against the
891  * nlmsg_validate_deprecated - validate a netlink message including attributes
903 	if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))  in nlmsg_validate_deprecated()
904 		return -EINVAL;  in nlmsg_validate_deprecated()
914  * nlmsg_report - need to report back to application?
921 	return nlh ? !!(nlh->nlmsg_flags & NLM_F_ECHO) : 0;  in nlmsg_report()
925  * nlmsg_seq - return the seq number of netlink message
932 	return nlh ? nlh->nlmsg_seq : 0;  in nlmsg_seq()
936  * nlmsg_for_each_attr - iterate over a stream of attributes
947  * nlmsg_put - Add a new netlink message to an skb
968  * nlmsg_append - Add more data to a nlmsg in a skb
973  * with multiple fixed-format headers (which is rare).
982 	if (NLMSG_ALIGN(size) - size)  in nlmsg_append()
984 		       NLMSG_ALIGN(size) - size);  in nlmsg_append()
989  * nlmsg_put_answer - Add a new callback based netlink message to an skb
1004 	return nlmsg_put(skb, NETLINK_CB(cb->skb).portid, cb->nlh->nlmsg_seq,  in nlmsg_put_answer()
1009  * nlmsg_new - Allocate a new netlink message
1022  * nlmsg_new_large - Allocate a new netlink message with non-contiguous
1026  * The allocated skb is unable to have frag page for shinfo->frags*,
1027  * as the NULL setting for skb->head in netlink_skb_destructor() will
1036  * nlmsg_end - Finalize a netlink message
1041  * attributes. Only necessary if attributes have been added to
1046 	nlh->nlmsg_len = skb_tail_pointer(skb) - (unsigned char *)nlh;  in nlmsg_end()
1050  * nlmsg_get_pos - return current position in netlink message
1061  * nlmsg_trim - Trim message to a mark
1070 		WARN_ON((unsigned char *) mark < skb->data);  in nlmsg_trim()
1071 		skb_trim(skb, (unsigned char *) mark - skb->data);  in nlmsg_trim()
1076  * nlmsg_cancel - Cancel construction of a netlink message
1081  * attributes from the socket buffer again.
1089  * nlmsg_free - drop a netlink message
1098  * nlmsg_consume - free a netlink message
1107  * nlmsg_multicast_filtered - multicast a netlink message with filter function
1137  * nlmsg_multicast - multicast a netlink message
1152  * nlmsg_unicast - unicast a netlink message
1169  * nlmsg_for_each_msg - iterate over a stream of messages
1181  * nl_dump_check_consistent - check if sequence is consistent and advertise if not
1188  * The correct way to use it is to set cb->seq to the generation counter when
1199 	if (cb->prev_seq && cb->seq != cb->prev_seq)  in nl_dump_check_consistent()
1200 		nlh->nlmsg_flags |= NLM_F_DUMP_INTR;  in nl_dump_check_consistent()
1201 	cb->prev_seq = cb->seq;  in nl_dump_check_consistent()
1205  * Netlink Attributes
1209  * nla_attr_size - length of attribute not including padding
1218  * nla_total_size - total length of attribute including padding
1227  * nla_padlen - length of padding at the tail of attribute
1232 	return nla_total_size(payload) - nla_attr_size(payload);  in nla_padlen()
1236  * nla_type - attribute type
1241 	return nla->nla_type & NLA_TYPE_MASK;  in nla_type()
1245  * nla_data - head of payload
1254  * nla_len - length of payload
1259 	return nla->nla_len - NLA_HDRLEN;  in nla_len()
1263  * nla_ok - check if the netlink attribute fits into the remaining bytes
1270 	       nla->nla_len >= sizeof(*nla) &&  in nla_ok()
1271 	       nla->nla_len <= remaining;  in nla_ok()
1275  * nla_next - next netlink attribute in attribute stream
1284 	unsigned int totlen = NLA_ALIGN(nla->nla_len);  in nla_next()
1286 	*remaining -= totlen;  in nla_next()
1291  * nla_find_nested - find attribute in a set of nested attributes
1292  * @nla: attribute containing the nested attributes
1304  * nla_parse_nested - parse nested attributes
1307  * @nla: attribute containing the nested attributes
1318 	if (!(nla->nla_type & NLA_F_NESTED)) {  in nla_parse_nested()
1320 		return -EINVAL;  in nla_parse_nested()
1328  * nla_parse_nested_deprecated - parse nested attributes
1331  * @nla: attribute containing the nested attributes
1347  * nla_put_u8 - Add a u8 netlink attribute to a socket buffer
1354 	/* temporary variables to work around GCC PR81715 with asan-stack=1 */  in nla_put_u8()
1361  * nla_put_u16 - Add a u16 netlink attribute to a socket buffer
1374  * nla_put_be16 - Add a __be16 netlink attribute to a socket buffer
1387  * nla_put_net16 - Add 16-bit network byte order netlink attribute to a socket buffer
1400  * nla_put_le16 - Add a __le16 netlink attribute to a socket buffer
1413  * nla_put_u32 - Add a u32 netlink attribute to a socket buffer
1426  * nla_put_uint - Add a variable-size unsigned int to a socket buffer
1442  * nla_put_be32 - Add a __be32 netlink attribute to a socket buffer
1455  * nla_put_net32 - Add 32-bit network byte order netlink attribute to a socket buffer
1468  * nla_put_le32 - Add a __le32 netlink attribute to a socket buffer
1481  * nla_put_u64_64bit - Add a u64 netlink attribute to a skb and align it
1496  * nla_put_be64 - Add a __be64 netlink attribute to a socket buffer and align it
1511  * nla_put_net64 - Add 64-bit network byte order nlattr to a skb and align it
1527  * nla_put_le64 - Add a __le64 netlink attribute to a socket buffer and align it
1542  * nla_put_s8 - Add a s8 netlink attribute to a socket buffer
1555  * nla_put_s16 - Add a s16 netlink attribute to a socket buffer
1568  * nla_put_s32 - Add a s32 netlink attribute to a socket buffer
1581  * nla_put_s64 - Add a s64 netlink attribute to a socket buffer and align it
1596  * nla_put_sint - Add a variable-size signed int to a socket buffer
1612  * nla_put_string - Add a string netlink attribute to a socket buffer
1624  * nla_put_flag - Add a flag netlink attribute to a socket buffer
1634  * nla_put_msecs - Add a msecs netlink attribute to a skb and align it
1649  * nla_put_in_addr - Add an IPv4 address netlink attribute to a socket
1664  * nla_put_in6_addr - Add an IPv6 address netlink attribute to a socket
1677  * nla_put_bitfield32 - Add a bitfield32 netlink attribute to a socket buffer
1692  * nla_get_u32 - return payload of u32 attribute
1701  * nla_get_u32_default - return payload of u32 attribute or default
1715  * nla_get_be32 - return payload of __be32 attribute
1724  * nla_get_be32_default - return payload of be32 attribute or default
1739  * nla_get_le32 - return payload of __le32 attribute
1748  * nla_get_le32_default - return payload of le32 attribute or default
1763  * nla_get_u16 - return payload of u16 attribute
1772  * nla_get_u16_default - return payload of u16 attribute or default
1786  * nla_get_be16 - return payload of __be16 attribute
1795  * nla_get_be16_default - return payload of be16 attribute or default
1810  * nla_get_le16 - return payload of __le16 attribute
1819  * nla_get_le16_default - return payload of le16 attribute or default
1834  * nla_get_u8 - return payload of u8 attribute
1843  * nla_get_u8_default - return payload of u8 attribute or default
1857  * nla_get_u64 - return payload of u64 attribute
1870  * nla_get_u64_default - return payload of u64 attribute or default
1884  * nla_get_uint - return payload of uint attribute
1895  * nla_get_uint_default - return payload of uint attribute or default
1909  * nla_get_be64 - return payload of __be64 attribute
1922  * nla_get_be64_default - return payload of be64 attribute or default
1937  * nla_get_le64 - return payload of __le64 attribute
1946  * nla_get_le64_default - return payload of le64 attribute or default
1961  * nla_get_s32 - return payload of s32 attribute
1970  * nla_get_s32_default - return payload of s32 attribute or default
1984  * nla_get_s16 - return payload of s16 attribute
1993  * nla_get_s16_default - return payload of s16 attribute or default
2007  * nla_get_s8 - return payload of s8 attribute
2016  * nla_get_s8_default - return payload of s8 attribute or default
2030  * nla_get_s64 - return payload of s64 attribute
2043  * nla_get_s64_default - return payload of s64 attribute or default
2057  * nla_get_sint - return payload of uint attribute
2068  * nla_get_sint_default - return payload of sint attribute or default
2082  * nla_get_flag - return payload of flag attribute
2091  * nla_get_msecs - return payload of msecs attribute
2104  * nla_get_msecs_default - return payload of msecs attribute or default
2119  * nla_get_in_addr - return payload of IPv4 address attribute
2128  * nla_get_in_addr_default - return payload of be32 attribute or default
2143  * nla_get_in6_addr - return payload of IPv6 address attribute
2155  * nla_get_bitfield32 - return payload of 32 bitfield attribute
2167  * nla_memdup - duplicate attribute memory (kmemdup)
2178  * nla_nest_start_noflag - Start a new level of nested attributes
2179  * @skb: socket buffer to add attributes to
2183  * marked their nest attributes with NLA_F_NESTED flag. New APIs should use
2200  * nla_nest_start - Start a new level of nested attributes, with NLA_F_NESTED
2201  * @skb: socket buffer to add attributes to
2215  * nla_nest_end - Finalize nesting of attributes
2216  * @skb: socket buffer the attributes are stored in
2220  * appended attributes.
2226 	start->nla_len = skb_tail_pointer(skb) - (unsigned char *)start;  in nla_nest_end()
2227 	return skb->len;  in nla_nest_end()
2231  * nla_nest_cancel - Cancel nesting of attributes
2235  * Removes the container attribute and including all nested
2236  * attributes. Returns -EMSGSIZE
2244  * __nla_validate_nested - Validate a stream of nested attributes
2251  * Validates all attributes in the nested attribute stream against the
2252  * specified policy. Attributes with a type exceeding maxtype will be
2285  * nla_need_padding_for_64bit - test 64-bit alignment of the next attribute
2289  * a 64-bit aligned area.
2295 	 * if the skb->data _is_ aligned.  A NOP attribute, plus  in nla_need_padding_for_64bit()
2297 	 * 8-byte aligned.  in nla_need_padding_for_64bit()
2306  * nla_align_64bit - 64-bit align the nla_data() of next attribute
2311  * the next attribute we emit have a 64-bit aligned nla_data() area.
2321 		return -EMSGSIZE;  in nla_align_64bit()
2327  * nla_total_size_64bit - total length of attribute including padding
2340  * nla_for_each_attr - iterate over a stream of attributes
2352  * nla_for_each_attr_type - iterate over a stream of attributes
2364  * nla_for_each_nested - iterate over nested attributes
2366  * @nla: attribute containing the nested attributes
2373  * nla_for_each_nested_type - iterate over nested attributes
2376  * @nla: attribute containing the nested attributes
2384  * nla_is_last - Test if attribute is last in stream
2390 	return nla->nla_len == rem;  in nla_is_last()