xref: /freebsd/sys/netlink/netlink.h (revision 8a271827e7b5d5310e06df1f9f49ba0ef9efd263)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3  *
4  * Copyright (c) 2021 Ng Peng Nam Sean
5  * Copyright (c) 2022 Alexander V. Chernikov <melifaro@FreeBSD.org>
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  *
16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19  * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26  * SUCH DAMAGE.
27  *
28  * Copyright (C) The Internet Society (2003).  All Rights Reserved.
29  *
30  * This document and translations of it may be copied and furnished to
31  * others, and derivative works that comment on or otherwise explain it
32  * or assist in its implementation may be prepared, copied, published
33  * and distributed, in whole or in part, without restriction of any
34  * kind, provided that the above copyright notice and this paragraph are
35  * included on all such copies and derivative works.  However, this
36  * document itself may not be modified in any way, such as by removing
37  * the copyright notice or references to the Internet Society or other
38  * Internet organizations, except as needed for the purpose of
39  * developing Internet standards in which case the procedures for
40  * copyrights defined in the Internet Standards process must be
41  * followed, or as required to translate it into languages other than
42  * English.
43  *
44  * The limited permissions granted above are perpetual and will not be
45  * revoked by the Internet Society or its successors or assignees.
46  *
47  * This document and the information contained herein is provided on an
48  * "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING
49  * TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING
50  * BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION
51  * HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF
52  * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
53 
54  */
55 
56 /*
57  * This file contains structures and constants for RFC 3549 (Netlink)
58  * protocol. Some values have been taken from Linux implementation.
59  */
60 
61 #ifndef _NETLINK_NETLINK_H_
62 #define _NETLINK_NETLINK_H_
63 
64 #include <sys/types.h>
65 #include <sys/socket.h>
66 
67 struct sockaddr_nl {
68 	uint8_t		nl_len;		/* sizeof(sockaddr_nl) */
69 	sa_family_t	nl_family;	/* netlink family */
70 	uint16_t	nl_pad;		/* reserved, set to 0 */
71 	uint32_t	nl_pid;		/* desired port ID, 0 for auto-select */
72 	uint32_t	nl_groups;	/* multicast groups mask to bind to */
73 };
74 
75 #define	SOL_NETLINK			270
76 
77 /* Netlink socket options */
78 #define NETLINK_ADD_MEMBERSHIP		1 /* Subscribe for the specified group notifications */
79 #define NETLINK_DROP_MEMBERSHIP		2 /* Unsubscribe from the specified group */
80 #define NETLINK_PKTINFO			3 /* XXX: not supported */
81 #define NETLINK_BROADCAST_ERROR		4 /* XXX: not supported */
82 #define NETLINK_NO_ENOBUFS		5 /* XXX: not supported */
83 #define NETLINK_RX_RING			6 /* XXX: not supported */
84 #define NETLINK_TX_RING			7 /* XXX: not supported */
85 #define NETLINK_LISTEN_ALL_NSID		8 /* XXX: not supported */
86 
87 #define NETLINK_LIST_MEMBERSHIPS	9
88 #define NETLINK_CAP_ACK			10 /* Send only original message header in the reply */
89 #define NETLINK_EXT_ACK			11 /* Ack support for receiving additional TLVs in ack */
90 #define NETLINK_GET_STRICT_CHK		12 /* Strict header checking */
91 
92 
93 /*
94  * RFC 3549, 2.3.2 Netlink Message Header
95  */
96 struct nlmsghdr {
97 	uint32_t nlmsg_len;   /* Length of message including header */
98 	uint16_t nlmsg_type;  /* Message type identifier */
99 	uint16_t nlmsg_flags; /* Flags (NLM_F_) */
100 	uint32_t nlmsg_seq;   /* Sequence number */
101 	uint32_t nlmsg_pid;   /* Sending process port ID */
102 };
103 
104 /*
105  * RFC 3549, 2.3.2 standard flag bits (nlmsg_flags)
106  */
107 #define NLM_F_REQUEST		0x01	/* Indicateds request to kernel */
108 #define NLM_F_MULTI		0x02	/* Message is part of a group terminated by NLMSG_DONE msg */
109 #define NLM_F_ACK		0x04	/* Reply with ack message containing resulting error code */
110 #define NLM_F_ECHO		0x08	/* (not supported) Echo this request back */
111 #define NLM_F_DUMP_INTR		0x10	/* Dump was inconsistent due to sequence change */
112 #define NLM_F_DUMP_FILTERED	0x20	/* Dump was filtered as requested */
113 
114 /*
115  * RFC 3549, 2.3.2 Additional flag bits for GET requests
116  */
117 #define NLM_F_ROOT		0x100	/* Return the complete table */
118 #define NLM_F_MATCH		0x200	/* Return all entries matching criteria */
119 #define NLM_F_ATOMIC		0x400	/* Return an atomic snapshot (ignored) */
120 #define NLM_F_DUMP		(NLM_F_ROOT | NLM_F_MATCH)
121 
122 /*
123  * RFC 3549, 2.3.2 Additional flag bits for NEW requests
124  */
125 #define NLM_F_REPLACE		0x100	/* Replace existing matching config object */
126 #define NLM_F_EXCL		0x200	/* Don't replace the object if exists */
127 #define NLM_F_CREATE		0x400	/* Create if it does not exist */
128 #define NLM_F_APPEND		0x800	/* Add to end of list */
129 
130 /* Modifiers to DELETE requests */
131 #define NLM_F_NONREC		0x100	/* Do not delete recursively */
132 
133 /* Flags for ACK message */
134 #define NLM_F_CAPPED		0x100	/* request was capped */
135 #define NLM_F_ACK_TLVS		0x200	/* extended ACK TVLs were included */
136 
137 /*
138  * RFC 3549, 2.3.2 standard message types (nlmsg_type).
139  */
140 #define NLMSG_NOOP		0x1	/* Message is ignored. */
141 #define NLMSG_ERROR		0x2	/* reply error code reporting */
142 #define NLMSG_DONE		0x3	/* Message terminates a multipart message. */
143 #define NLMSG_OVERRUN		0x4	/* overrun detected, data is lost */
144 
145 #define NLMSG_MIN_TYPE		0x10	/* < 0x10: reserved control messages */
146 
147 /*
148  * Defition of numbers assigned to the netlink subsystems.
149  */
150 #define NETLINK_ROUTE		0	/* Routing/device hook */
151 #define NETLINK_UNUSED		1	/* not supported */
152 #define NETLINK_USERSOCK	2	/* not supported */
153 #define NETLINK_FIREWALL	3	/* not supported */
154 #define NETLINK_SOCK_DIAG	4	/* not supported */
155 #define NETLINK_NFLOG		5	/* not supported */
156 #define NETLINK_XFRM		6	/* (not supported) PF_SETKEY */
157 #define NETLINK_SELINUX		7	/* not supported */
158 #define NETLINK_ISCSI		8	/* not supported */
159 #define NETLINK_AUDIT		9	/* not supported */
160 #define NETLINK_FIB_LOOKUP	10	/* not supported */
161 #define NETLINK_CONNECTOR	11	/* not supported */
162 #define NETLINK_NETFILTER	12	/* not supported */
163 #define NETLINK_IP6_FW		13	/* not supported  */
164 #define NETLINK_DNRTMSG		14	/* not supported */
165 #define NETLINK_KOBJECT_UEVENT	15	/* not supported */
166 #define NETLINK_GENERIC		16	/* Generic netlink (dynamic families) */
167 
168 /*
169  * RFC 3549, 2.3.2.2 The ACK Netlink Message
170  */
171 struct nlmsgerr {
172 	int	error;
173 	struct	nlmsghdr msg;
174 };
175 
176 enum nlmsgerr_attrs {
177 	NLMSGERR_ATTR_UNUSED,
178 	NLMSGERR_ATTR_MSG	= 1, /* string, error message */
179 	NLMSGERR_ATTR_OFFS	= 2, /* u32, offset of the invalid attr from nl header */
180 	NLMSGERR_ATTR_COOKIE	= 3, /* binary, data to pass to userland */
181 	NLMSGERR_ATTR_POLICY	= 4, /* not supported */
182 	__NLMSGERR_ATTR_MAX,
183 	NLMSGERR_ATTR_MAX = __NLMSGERR_ATTR_MAX - 1
184 };
185 
186 
187 #ifndef roundup2
188 #define	roundup2(x, y)	(((x)+((y)-1))&(~((y)-1))) /* if y is powers of two */
189 #endif
190 #define	NL_ITEM_ALIGN_SIZE		sizeof(uint32_t)
191 #define	NL_ITEM_ALIGN(_len)		roundup2(_len, NL_ITEM_ALIGN_SIZE)
192 #define	NL_ITEM_DATA(_ptr, _off)	((void *)((char *)(_ptr) + _off))
193 #define	NL_ITEM_DATA_CONST(_ptr, _off)	((const void *)((const char *)(_ptr) + _off))
194 
195 #define	NL_ITEM_OK(_ptr, _len, _hlen, _LEN_M)	\
196 	((_len) >= _hlen && _LEN_M(_ptr) >= _hlen && _LEN_M(_ptr) <= (_len))
197 #define	NL_ITEM_NEXT(_ptr, _LEN_M)	((typeof(_ptr))((char *)(_ptr) + _LEN_M(_ptr)))
198 #define	NL_ITEM_ITER(_ptr, _len, _LEN_MACRO)	\
199 	((_len) -= _LEN_MACRO(_ptr), NL_ITEM_NEXT(_ptr, _LEN_MACRO))
200 
201 
202 #ifndef _KERNEL
203 /* part of netlink(3) API */
204 #define NLMSG_ALIGNTO			NL_ITEM_ALIGN_SIZE
205 #define NLMSG_ALIGN(_len)		NL_ITEM_ALIGN(_len)
206 #define NLMSG_HDRLEN			((int)sizeof(struct nlmsghdr))
207 #define NLMSG_LENGTH(_len)		((_len) + NLMSG_HDRLEN)
208 #define NLMSG_SPACE(_len)		NLMSG_ALIGN(NLMSG_LENGTH(_len))
209 #define NLMSG_DATA(_hdr)		NL_ITEM_DATA(_hdr, NLMSG_HDRLEN)
210 #define	_NLMSG_LEN(_hdr)		((int)(_hdr)->nlmsg_len)
211 #define	_NLMSG_ALIGNED_LEN(_hdr)	NLMSG_ALIGN(_NLMSG_LEN(_hdr))
212 #define	NLMSG_OK(_hdr, _len)		NL_ITEM_OK(_hdr, _len, NLMSG_HDRLEN, _NLMSG_LEN)
213 #define NLMSG_PAYLOAD(_hdr,_len)	(_NLMSG_LEN(_hdr) - NLMSG_SPACE((_len)))
214 #define	NLMSG_NEXT(_hdr, _len)		NL_ITEM_ITER(_hdr, _len, _NLMSG_ALIGNED_LEN)
215 
216 #else
217 #define NLMSG_ALIGNTO 4U
218 #define NLMSG_ALIGN(len) (((len) + NLMSG_ALIGNTO - 1) & ~(NLMSG_ALIGNTO - 1))
219 #define NLMSG_HDRLEN ((int)NLMSG_ALIGN(sizeof(struct nlmsghdr)))
220 #endif
221 
222 /*
223  * Base netlink attribute TLV header.
224  */
225 struct nlattr {
226 	uint16_t nla_len;	/* Total attribute length */
227 	uint16_t nla_type;	/* Attribute type */
228 };
229 
230 /*
231  *
232  * nl_type field enconding:
233  *
234  * 0                   1
235  * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6
236  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
237  * |N|O|  Attribute type           |
238  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
239  * N - attribute contains other attributes (mostly unused)
240  * O - encoded in network byte order (mostly unused)
241  * Note: N & O are mutually exclusive
242  *
243  * Note: attribute type value scope normally is either parent attribute
244  * or the message/message group.
245  */
246 
247 #define NLA_F_NESTED (1 << 15)
248 #define NLA_F_NET_BYTEORDER (1 << 14)
249 #define NLA_TYPE_MASK ~(NLA_F_NESTED | NLA_F_NET_BYTEORDER)
250 
251 #ifndef _KERNEL
252 #define	NLA_ALIGNTO	NL_ITEM_ALIGN_SIZE
253 #define	NLA_ALIGN(_len)	NL_ITEM_ALIGN(_len)
254 #define	NLA_HDRLEN	((int)sizeof(struct nlattr))
255 #endif
256 
257 #endif
258