xref: /linux-6.15/include/linux/netlink.h (revision 173d6681)
1 #ifndef __LINUX_NETLINK_H
2 #define __LINUX_NETLINK_H
3 
4 #include <linux/socket.h> /* for sa_family_t */
5 #include <linux/types.h>
6 
7 #define NETLINK_ROUTE		0	/* Routing/device hook				*/
8 #define NETLINK_UNUSED		1	/* Unused number				*/
9 #define NETLINK_USERSOCK	2	/* Reserved for user mode socket protocols 	*/
10 #define NETLINK_FIREWALL	3	/* Firewalling hook				*/
11 #define NETLINK_INET_DIAG	4	/* INET socket monitoring			*/
12 #define NETLINK_NFLOG		5	/* netfilter/iptables ULOG */
13 #define NETLINK_XFRM		6	/* ipsec */
14 #define NETLINK_SELINUX		7	/* SELinux event notifications */
15 #define NETLINK_ISCSI		8	/* Open-iSCSI */
16 #define NETLINK_AUDIT		9	/* auditing */
17 #define NETLINK_FIB_LOOKUP	10
18 #define NETLINK_CONNECTOR	11
19 #define NETLINK_NETFILTER	12	/* netfilter subsystem */
20 #define NETLINK_IP6_FW		13
21 #define NETLINK_DNRTMSG		14	/* DECnet routing messages */
22 #define NETLINK_KOBJECT_UEVENT	15	/* Kernel messages to userspace */
23 #define NETLINK_GENERIC		16
24 /* leave room for NETLINK_DM (DM Events) */
25 #define NETLINK_SCSITRANSPORT	18	/* SCSI Transports */
26 
27 #define MAX_LINKS 32
28 
29 struct sockaddr_nl
30 {
31 	sa_family_t	nl_family;	/* AF_NETLINK	*/
32 	unsigned short	nl_pad;		/* zero		*/
33 	__u32		nl_pid;		/* process pid	*/
34        	__u32		nl_groups;	/* multicast groups mask */
35 };
36 
37 struct nlmsghdr
38 {
39 	__u32		nlmsg_len;	/* Length of message including header */
40 	__u16		nlmsg_type;	/* Message content */
41 	__u16		nlmsg_flags;	/* Additional flags */
42 	__u32		nlmsg_seq;	/* Sequence number */
43 	__u32		nlmsg_pid;	/* Sending process PID */
44 };
45 
46 /* Flags values */
47 
48 #define NLM_F_REQUEST		1	/* It is request message. 	*/
49 #define NLM_F_MULTI		2	/* Multipart message, terminated by NLMSG_DONE */
50 #define NLM_F_ACK		4	/* Reply with ack, with zero or error code */
51 #define NLM_F_ECHO		8	/* Echo this request 		*/
52 
53 /* Modifiers to GET request */
54 #define NLM_F_ROOT	0x100	/* specify tree	root	*/
55 #define NLM_F_MATCH	0x200	/* return all matching	*/
56 #define NLM_F_ATOMIC	0x400	/* atomic GET		*/
57 #define NLM_F_DUMP	(NLM_F_ROOT|NLM_F_MATCH)
58 
59 /* Modifiers to NEW request */
60 #define NLM_F_REPLACE	0x100	/* Override existing		*/
61 #define NLM_F_EXCL	0x200	/* Do not touch, if it exists	*/
62 #define NLM_F_CREATE	0x400	/* Create, if it does not exist	*/
63 #define NLM_F_APPEND	0x800	/* Add to end of list		*/
64 
65 /*
66    4.4BSD ADD		NLM_F_CREATE|NLM_F_EXCL
67    4.4BSD CHANGE	NLM_F_REPLACE
68 
69    True CHANGE		NLM_F_CREATE|NLM_F_REPLACE
70    Append		NLM_F_CREATE
71    Check		NLM_F_EXCL
72  */
73 
74 #define NLMSG_ALIGNTO	4
75 #define NLMSG_ALIGN(len) ( ((len)+NLMSG_ALIGNTO-1) & ~(NLMSG_ALIGNTO-1) )
76 #define NLMSG_HDRLEN	 ((int) NLMSG_ALIGN(sizeof(struct nlmsghdr)))
77 #define NLMSG_LENGTH(len) ((len)+NLMSG_ALIGN(NLMSG_HDRLEN))
78 #define NLMSG_SPACE(len) NLMSG_ALIGN(NLMSG_LENGTH(len))
79 #define NLMSG_DATA(nlh)  ((void*)(((char*)nlh) + NLMSG_LENGTH(0)))
80 #define NLMSG_NEXT(nlh,len)	 ((len) -= NLMSG_ALIGN((nlh)->nlmsg_len), \
81 				  (struct nlmsghdr*)(((char*)(nlh)) + NLMSG_ALIGN((nlh)->nlmsg_len)))
82 #define NLMSG_OK(nlh,len) ((len) >= (int)sizeof(struct nlmsghdr) && \
83 			   (nlh)->nlmsg_len >= sizeof(struct nlmsghdr) && \
84 			   (nlh)->nlmsg_len <= (len))
85 #define NLMSG_PAYLOAD(nlh,len) ((nlh)->nlmsg_len - NLMSG_SPACE((len)))
86 
87 #define NLMSG_NOOP		0x1	/* Nothing.		*/
88 #define NLMSG_ERROR		0x2	/* Error		*/
89 #define NLMSG_DONE		0x3	/* End of a dump	*/
90 #define NLMSG_OVERRUN		0x4	/* Data lost		*/
91 
92 #define NLMSG_MIN_TYPE		0x10	/* < 0x10: reserved control messages */
93 
94 struct nlmsgerr
95 {
96 	int		error;
97 	struct nlmsghdr msg;
98 };
99 
100 #define NETLINK_ADD_MEMBERSHIP	1
101 #define NETLINK_DROP_MEMBERSHIP	2
102 #define NETLINK_PKTINFO		3
103 
104 struct nl_pktinfo
105 {
106 	__u32	group;
107 };
108 
109 #define NET_MAJOR 36		/* Major 36 is reserved for networking 						*/
110 
111 enum {
112 	NETLINK_UNCONNECTED = 0,
113 	NETLINK_CONNECTED,
114 };
115 
116 /*
117  *  <------- NLA_HDRLEN ------> <-- NLA_ALIGN(payload)-->
118  * +---------------------+- - -+- - - - - - - - - -+- - -+
119  * |        Header       | Pad |     Payload       | Pad |
120  * |   (struct nlattr)   | ing |                   | ing |
121  * +---------------------+- - -+- - - - - - - - - -+- - -+
122  *  <-------------- nlattr->nla_len -------------->
123  */
124 
125 struct nlattr
126 {
127 	__u16           nla_len;
128 	__u16           nla_type;
129 };
130 
131 #define NLA_ALIGNTO		4
132 #define NLA_ALIGN(len)		(((len) + NLA_ALIGNTO - 1) & ~(NLA_ALIGNTO - 1))
133 #define NLA_HDRLEN		((int) NLA_ALIGN(sizeof(struct nlattr)))
134 
135 #ifdef __KERNEL__
136 
137 #include <linux/capability.h>
138 #include <linux/skbuff.h>
139 
140 struct netlink_skb_parms
141 {
142 	struct ucred		creds;		/* Skb credentials	*/
143 	__u32			pid;
144 	__u32			dst_group;
145 	kernel_cap_t		eff_cap;
146 	__u32			loginuid;	/* Login (audit) uid */
147 	__u32			sid;		/* SELinux security id */
148 };
149 
150 #define NETLINK_CB(skb)		(*(struct netlink_skb_parms*)&((skb)->cb))
151 #define NETLINK_CREDS(skb)	(&NETLINK_CB((skb)).creds)
152 
153 
154 extern struct sock *netlink_kernel_create(int unit, unsigned int groups, void (*input)(struct sock *sk, int len), struct module *module);
155 extern void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err);
156 extern int netlink_has_listeners(struct sock *sk, unsigned int group);
157 extern int netlink_unicast(struct sock *ssk, struct sk_buff *skb, __u32 pid, int nonblock);
158 extern int netlink_broadcast(struct sock *ssk, struct sk_buff *skb, __u32 pid,
159 			     __u32 group, gfp_t allocation);
160 extern void netlink_set_err(struct sock *ssk, __u32 pid, __u32 group, int code);
161 extern int netlink_register_notifier(struct notifier_block *nb);
162 extern int netlink_unregister_notifier(struct notifier_block *nb);
163 
164 /* finegrained unicast helpers: */
165 struct sock *netlink_getsockbyfilp(struct file *filp);
166 int netlink_attachskb(struct sock *sk, struct sk_buff *skb, int nonblock,
167 		long timeo, struct sock *ssk);
168 void netlink_detachskb(struct sock *sk, struct sk_buff *skb);
169 int netlink_sendskb(struct sock *sk, struct sk_buff *skb, int protocol);
170 
171 /*
172  *	skb should fit one page. This choice is good for headerless malloc.
173  */
174 #define NLMSG_GOODORDER 0
175 #define NLMSG_GOODSIZE (SKB_MAX_ORDER(0, NLMSG_GOODORDER))
176 #define NLMSG_DEFAULT_SIZE (NLMSG_GOODSIZE - NLMSG_HDRLEN)
177 
178 
179 struct netlink_callback
180 {
181 	struct sk_buff	*skb;
182 	struct nlmsghdr	*nlh;
183 	int		(*dump)(struct sk_buff * skb, struct netlink_callback *cb);
184 	int		(*done)(struct netlink_callback *cb);
185 	int		family;
186 	long		args[5];
187 };
188 
189 struct netlink_notify
190 {
191 	int pid;
192 	int protocol;
193 };
194 
195 static __inline__ struct nlmsghdr *
196 __nlmsg_put(struct sk_buff *skb, u32 pid, u32 seq, int type, int len, int flags)
197 {
198 	struct nlmsghdr *nlh;
199 	int size = NLMSG_LENGTH(len);
200 
201 	nlh = (struct nlmsghdr*)skb_put(skb, NLMSG_ALIGN(size));
202 	nlh->nlmsg_type = type;
203 	nlh->nlmsg_len = size;
204 	nlh->nlmsg_flags = flags;
205 	nlh->nlmsg_pid = pid;
206 	nlh->nlmsg_seq = seq;
207 	memset(NLMSG_DATA(nlh) + len, 0, NLMSG_ALIGN(size) - size);
208 	return nlh;
209 }
210 
211 #define NLMSG_NEW(skb, pid, seq, type, len, flags) \
212 ({	if (skb_tailroom(skb) < (int)NLMSG_SPACE(len)) \
213 		goto nlmsg_failure; \
214 	__nlmsg_put(skb, pid, seq, type, len, flags); })
215 
216 #define NLMSG_PUT(skb, pid, seq, type, len) \
217 	NLMSG_NEW(skb, pid, seq, type, len, 0)
218 
219 #define NLMSG_NEW_ANSWER(skb, cb, type, len, flags) \
220 	NLMSG_NEW(skb, NETLINK_CB((cb)->skb).pid, \
221 		  (cb)->nlh->nlmsg_seq, type, len, flags)
222 
223 #define NLMSG_END(skb, nlh) \
224 ({	(nlh)->nlmsg_len = (skb)->tail - (unsigned char *) (nlh); \
225 	(skb)->len; })
226 
227 #define NLMSG_CANCEL(skb, nlh) \
228 ({	skb_trim(skb, (unsigned char *) (nlh) - (skb)->data); \
229 	-1; })
230 
231 extern int netlink_dump_start(struct sock *ssk, struct sk_buff *skb,
232 			      struct nlmsghdr *nlh,
233 			      int (*dump)(struct sk_buff *skb, struct netlink_callback*),
234 			      int (*done)(struct netlink_callback*));
235 
236 
237 #define NL_NONROOT_RECV 0x1
238 #define NL_NONROOT_SEND 0x2
239 extern void netlink_set_nonroot(int protocol, unsigned flag);
240 
241 #endif /* __KERNEL__ */
242 
243 #endif	/* __LINUX_NETLINK_H */
244