xref: /linux-6.15/include/linux/netlink.h (revision 8802f616)
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 
25 #define MAX_LINKS 32
26 
27 struct sockaddr_nl
28 {
29 	sa_family_t	nl_family;	/* AF_NETLINK	*/
30 	unsigned short	nl_pad;		/* zero		*/
31 	__u32		nl_pid;		/* process pid	*/
32        	__u32		nl_groups;	/* multicast groups mask */
33 };
34 
35 struct nlmsghdr
36 {
37 	__u32		nlmsg_len;	/* Length of message including header */
38 	__u16		nlmsg_type;	/* Message content */
39 	__u16		nlmsg_flags;	/* Additional flags */
40 	__u32		nlmsg_seq;	/* Sequence number */
41 	__u32		nlmsg_pid;	/* Sending process PID */
42 };
43 
44 /* Flags values */
45 
46 #define NLM_F_REQUEST		1	/* It is request message. 	*/
47 #define NLM_F_MULTI		2	/* Multipart message, terminated by NLMSG_DONE */
48 #define NLM_F_ACK		4	/* Reply with ack, with zero or error code */
49 #define NLM_F_ECHO		8	/* Echo this request 		*/
50 
51 /* Modifiers to GET request */
52 #define NLM_F_ROOT	0x100	/* specify tree	root	*/
53 #define NLM_F_MATCH	0x200	/* return all matching	*/
54 #define NLM_F_ATOMIC	0x400	/* atomic GET		*/
55 #define NLM_F_DUMP	(NLM_F_ROOT|NLM_F_MATCH)
56 
57 /* Modifiers to NEW request */
58 #define NLM_F_REPLACE	0x100	/* Override existing		*/
59 #define NLM_F_EXCL	0x200	/* Do not touch, if it exists	*/
60 #define NLM_F_CREATE	0x400	/* Create, if it does not exist	*/
61 #define NLM_F_APPEND	0x800	/* Add to end of list		*/
62 
63 /*
64    4.4BSD ADD		NLM_F_CREATE|NLM_F_EXCL
65    4.4BSD CHANGE	NLM_F_REPLACE
66 
67    True CHANGE		NLM_F_CREATE|NLM_F_REPLACE
68    Append		NLM_F_CREATE
69    Check		NLM_F_EXCL
70  */
71 
72 #define NLMSG_ALIGNTO	4
73 #define NLMSG_ALIGN(len) ( ((len)+NLMSG_ALIGNTO-1) & ~(NLMSG_ALIGNTO-1) )
74 #define NLMSG_HDRLEN	 ((int) NLMSG_ALIGN(sizeof(struct nlmsghdr)))
75 #define NLMSG_LENGTH(len) ((len)+NLMSG_ALIGN(NLMSG_HDRLEN))
76 #define NLMSG_SPACE(len) NLMSG_ALIGN(NLMSG_LENGTH(len))
77 #define NLMSG_DATA(nlh)  ((void*)(((char*)nlh) + NLMSG_LENGTH(0)))
78 #define NLMSG_NEXT(nlh,len)	 ((len) -= NLMSG_ALIGN((nlh)->nlmsg_len), \
79 				  (struct nlmsghdr*)(((char*)(nlh)) + NLMSG_ALIGN((nlh)->nlmsg_len)))
80 #define NLMSG_OK(nlh,len) ((len) >= (int)sizeof(struct nlmsghdr) && \
81 			   (nlh)->nlmsg_len >= sizeof(struct nlmsghdr) && \
82 			   (nlh)->nlmsg_len <= (len))
83 #define NLMSG_PAYLOAD(nlh,len) ((nlh)->nlmsg_len - NLMSG_SPACE((len)))
84 
85 #define NLMSG_NOOP		0x1	/* Nothing.		*/
86 #define NLMSG_ERROR		0x2	/* Error		*/
87 #define NLMSG_DONE		0x3	/* End of a dump	*/
88 #define NLMSG_OVERRUN		0x4	/* Data lost		*/
89 
90 #define NLMSG_MIN_TYPE		0x10	/* < 0x10: reserved control messages */
91 
92 struct nlmsgerr
93 {
94 	int		error;
95 	struct nlmsghdr msg;
96 };
97 
98 #define NETLINK_ADD_MEMBERSHIP	1
99 #define NETLINK_DROP_MEMBERSHIP	2
100 #define NETLINK_PKTINFO		3
101 
102 struct nl_pktinfo
103 {
104 	__u32	group;
105 };
106 
107 #define NET_MAJOR 36		/* Major 36 is reserved for networking 						*/
108 
109 enum {
110 	NETLINK_UNCONNECTED = 0,
111 	NETLINK_CONNECTED,
112 };
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 
123 struct 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 
133 #ifdef __KERNEL__
134 
135 #include <linux/capability.h>
136 #include <linux/skbuff.h>
137 
138 struct netlink_skb_parms
139 {
140 	struct ucred		creds;		/* Skb credentials	*/
141 	__u32			pid;
142 	__u32			dst_pid;
143 	__u32			dst_group;
144 	kernel_cap_t		eff_cap;
145 	__u32			loginuid;	/* Login (audit) uid */
146 	__u32			sid;		/* SELinux security id */
147 };
148 
149 #define NETLINK_CB(skb)		(*(struct netlink_skb_parms*)&((skb)->cb))
150 #define NETLINK_CREDS(skb)	(&NETLINK_CB((skb)).creds)
151 
152 
153 extern struct sock *netlink_kernel_create(int unit, unsigned int groups, void (*input)(struct sock *sk, int len), struct module *module);
154 extern void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err);
155 extern int netlink_has_listeners(struct sock *sk, unsigned int group);
156 extern int netlink_unicast(struct sock *ssk, struct sk_buff *skb, __u32 pid, int nonblock);
157 extern int netlink_broadcast(struct sock *ssk, struct sk_buff *skb, __u32 pid,
158 			     __u32 group, gfp_t allocation);
159 extern void netlink_set_err(struct sock *ssk, __u32 pid, __u32 group, int code);
160 extern int netlink_register_notifier(struct notifier_block *nb);
161 extern int netlink_unregister_notifier(struct notifier_block *nb);
162 
163 /* finegrained unicast helpers: */
164 struct sock *netlink_getsockbyfilp(struct file *filp);
165 int netlink_attachskb(struct sock *sk, struct sk_buff *skb, int nonblock,
166 		long timeo, struct sock *ssk);
167 void netlink_detachskb(struct sock *sk, struct sk_buff *skb);
168 int netlink_sendskb(struct sock *sk, struct sk_buff *skb, int protocol);
169 
170 /*
171  *	skb should fit one page. This choice is good for headerless malloc.
172  */
173 #define NLMSG_GOODORDER 0
174 #define NLMSG_GOODSIZE (SKB_MAX_ORDER(0, NLMSG_GOODORDER))
175 
176 
177 struct netlink_callback
178 {
179 	struct sk_buff	*skb;
180 	struct nlmsghdr	*nlh;
181 	int		(*dump)(struct sk_buff * skb, struct netlink_callback *cb);
182 	int		(*done)(struct netlink_callback *cb);
183 	int		family;
184 	long		args[5];
185 };
186 
187 struct netlink_notify
188 {
189 	int pid;
190 	int protocol;
191 };
192 
193 static __inline__ struct nlmsghdr *
194 __nlmsg_put(struct sk_buff *skb, u32 pid, u32 seq, int type, int len, int flags)
195 {
196 	struct nlmsghdr *nlh;
197 	int size = NLMSG_LENGTH(len);
198 
199 	nlh = (struct nlmsghdr*)skb_put(skb, NLMSG_ALIGN(size));
200 	nlh->nlmsg_type = type;
201 	nlh->nlmsg_len = size;
202 	nlh->nlmsg_flags = flags;
203 	nlh->nlmsg_pid = pid;
204 	nlh->nlmsg_seq = seq;
205 	memset(NLMSG_DATA(nlh) + len, 0, NLMSG_ALIGN(size) - size);
206 	return nlh;
207 }
208 
209 #define NLMSG_NEW(skb, pid, seq, type, len, flags) \
210 ({	if (skb_tailroom(skb) < (int)NLMSG_SPACE(len)) \
211 		goto nlmsg_failure; \
212 	__nlmsg_put(skb, pid, seq, type, len, flags); })
213 
214 #define NLMSG_PUT(skb, pid, seq, type, len) \
215 	NLMSG_NEW(skb, pid, seq, type, len, 0)
216 
217 #define NLMSG_NEW_ANSWER(skb, cb, type, len, flags) \
218 	NLMSG_NEW(skb, NETLINK_CB((cb)->skb).pid, \
219 		  (cb)->nlh->nlmsg_seq, type, len, flags)
220 
221 #define NLMSG_END(skb, nlh) \
222 ({	(nlh)->nlmsg_len = (skb)->tail - (unsigned char *) (nlh); \
223 	(skb)->len; })
224 
225 #define NLMSG_CANCEL(skb, nlh) \
226 ({	skb_trim(skb, (unsigned char *) (nlh) - (skb)->data); \
227 	-1; })
228 
229 extern int netlink_dump_start(struct sock *ssk, struct sk_buff *skb,
230 			      struct nlmsghdr *nlh,
231 			      int (*dump)(struct sk_buff *skb, struct netlink_callback*),
232 			      int (*done)(struct netlink_callback*));
233 
234 
235 #define NL_NONROOT_RECV 0x1
236 #define NL_NONROOT_SEND 0x2
237 extern void netlink_set_nonroot(int protocol, unsigned flag);
238 
239 #endif /* __KERNEL__ */
240 
241 #endif	/* __LINUX_NETLINK_H */
242