xref: /linux-6.15/include/linux/netlink.h (revision 4e57b681)
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_W1		1	/* 1-wire subsystem				*/
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_LENGTH(len) ((len)+NLMSG_ALIGN(sizeof(struct nlmsghdr)))
75 #define NLMSG_SPACE(len) NLMSG_ALIGN(NLMSG_LENGTH(len))
76 #define NLMSG_DATA(nlh)  ((void*)(((char*)nlh) + NLMSG_LENGTH(0)))
77 #define NLMSG_NEXT(nlh,len)	 ((len) -= NLMSG_ALIGN((nlh)->nlmsg_len), \
78 				  (struct nlmsghdr*)(((char*)(nlh)) + NLMSG_ALIGN((nlh)->nlmsg_len)))
79 #define NLMSG_OK(nlh,len) ((len) >= (int)sizeof(struct nlmsghdr) && \
80 			   (nlh)->nlmsg_len >= sizeof(struct nlmsghdr) && \
81 			   (nlh)->nlmsg_len <= (len))
82 #define NLMSG_PAYLOAD(nlh,len) ((nlh)->nlmsg_len - NLMSG_SPACE((len)))
83 
84 #define NLMSG_NOOP		0x1	/* Nothing.		*/
85 #define NLMSG_ERROR		0x2	/* Error		*/
86 #define NLMSG_DONE		0x3	/* End of a dump	*/
87 #define NLMSG_OVERRUN		0x4	/* Data lost		*/
88 
89 struct nlmsgerr
90 {
91 	int		error;
92 	struct nlmsghdr msg;
93 };
94 
95 #define NETLINK_ADD_MEMBERSHIP	1
96 #define NETLINK_DROP_MEMBERSHIP	2
97 #define NETLINK_PKTINFO		3
98 
99 struct nl_pktinfo
100 {
101 	__u32	group;
102 };
103 
104 #define NET_MAJOR 36		/* Major 36 is reserved for networking 						*/
105 
106 enum {
107 	NETLINK_UNCONNECTED = 0,
108 	NETLINK_CONNECTED,
109 };
110 
111 #ifdef __KERNEL__
112 
113 #include <linux/capability.h>
114 #include <linux/skbuff.h>
115 
116 struct netlink_skb_parms
117 {
118 	struct ucred		creds;		/* Skb credentials	*/
119 	__u32			pid;
120 	__u32			dst_pid;
121 	__u32			dst_group;
122 	kernel_cap_t		eff_cap;
123 	__u32			loginuid;	/* Login (audit) uid */
124 };
125 
126 #define NETLINK_CB(skb)		(*(struct netlink_skb_parms*)&((skb)->cb))
127 #define NETLINK_CREDS(skb)	(&NETLINK_CB((skb)).creds)
128 
129 
130 extern struct sock *netlink_kernel_create(int unit, unsigned int groups, void (*input)(struct sock *sk, int len), struct module *module);
131 extern void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err);
132 extern int netlink_unicast(struct sock *ssk, struct sk_buff *skb, __u32 pid, int nonblock);
133 extern int netlink_broadcast(struct sock *ssk, struct sk_buff *skb, __u32 pid,
134 			     __u32 group, gfp_t allocation);
135 extern void netlink_set_err(struct sock *ssk, __u32 pid, __u32 group, int code);
136 extern int netlink_register_notifier(struct notifier_block *nb);
137 extern int netlink_unregister_notifier(struct notifier_block *nb);
138 
139 /* finegrained unicast helpers: */
140 struct sock *netlink_getsockbyfilp(struct file *filp);
141 int netlink_attachskb(struct sock *sk, struct sk_buff *skb, int nonblock, long timeo);
142 void netlink_detachskb(struct sock *sk, struct sk_buff *skb);
143 int netlink_sendskb(struct sock *sk, struct sk_buff *skb, int protocol);
144 
145 /*
146  *	skb should fit one page. This choice is good for headerless malloc.
147  */
148 #define NLMSG_GOODORDER 0
149 #define NLMSG_GOODSIZE (SKB_MAX_ORDER(0, NLMSG_GOODORDER))
150 
151 
152 struct netlink_callback
153 {
154 	struct sk_buff	*skb;
155 	struct nlmsghdr	*nlh;
156 	int		(*dump)(struct sk_buff * skb, struct netlink_callback *cb);
157 	int		(*done)(struct netlink_callback *cb);
158 	int		family;
159 	long		args[5];
160 };
161 
162 struct netlink_notify
163 {
164 	int pid;
165 	int protocol;
166 };
167 
168 static __inline__ struct nlmsghdr *
169 __nlmsg_put(struct sk_buff *skb, u32 pid, u32 seq, int type, int len, int flags)
170 {
171 	struct nlmsghdr *nlh;
172 	int size = NLMSG_LENGTH(len);
173 
174 	nlh = (struct nlmsghdr*)skb_put(skb, NLMSG_ALIGN(size));
175 	nlh->nlmsg_type = type;
176 	nlh->nlmsg_len = size;
177 	nlh->nlmsg_flags = flags;
178 	nlh->nlmsg_pid = pid;
179 	nlh->nlmsg_seq = seq;
180 	memset(NLMSG_DATA(nlh) + len, 0, NLMSG_ALIGN(size) - size);
181 	return nlh;
182 }
183 
184 #define NLMSG_NEW(skb, pid, seq, type, len, flags) \
185 ({	if (skb_tailroom(skb) < (int)NLMSG_SPACE(len)) \
186 		goto nlmsg_failure; \
187 	__nlmsg_put(skb, pid, seq, type, len, flags); })
188 
189 #define NLMSG_PUT(skb, pid, seq, type, len) \
190 	NLMSG_NEW(skb, pid, seq, type, len, 0)
191 
192 #define NLMSG_NEW_ANSWER(skb, cb, type, len, flags) \
193 	NLMSG_NEW(skb, NETLINK_CB((cb)->skb).pid, \
194 		  (cb)->nlh->nlmsg_seq, type, len, flags)
195 
196 #define NLMSG_END(skb, nlh) \
197 ({	(nlh)->nlmsg_len = (skb)->tail - (unsigned char *) (nlh); \
198 	(skb)->len; })
199 
200 #define NLMSG_CANCEL(skb, nlh) \
201 ({	skb_trim(skb, (unsigned char *) (nlh) - (skb)->data); \
202 	-1; })
203 
204 extern int netlink_dump_start(struct sock *ssk, struct sk_buff *skb,
205 			      struct nlmsghdr *nlh,
206 			      int (*dump)(struct sk_buff *skb, struct netlink_callback*),
207 			      int (*done)(struct netlink_callback*));
208 
209 
210 #define NL_NONROOT_RECV 0x1
211 #define NL_NONROOT_SEND 0x2
212 extern void netlink_set_nonroot(int protocol, unsigned flag);
213 
214 #endif /* __KERNEL__ */
215 
216 #endif	/* __LINUX_NETLINK_H */
217