xref: /linux-6.15/include/linux/netlink.h (revision 776cfebb)
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_SKIP		1	/* Reserved for ENskip  			*/
9 #define NETLINK_USERSOCK	2	/* Reserved for user mode socket protocols 	*/
10 #define NETLINK_FIREWALL	3	/* Firewalling hook				*/
11 #define NETLINK_TCPDIAG		4	/* TCP 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_ARPD		8
16 #define NETLINK_AUDIT		9	/* auditing */
17 #define NETLINK_ROUTE6		11	/* af_inet6 route comm channel */
18 #define NETLINK_IP6_FW		13
19 #define NETLINK_DNRTMSG		14	/* DECnet routing messages */
20 #define NETLINK_KOBJECT_UEVENT	15	/* Kernel messages to userspace */
21 #define NETLINK_TAPBASE		16	/* 16 to 31 are ethertap */
22 
23 #define MAX_LINKS 32
24 
25 struct sockaddr_nl
26 {
27 	sa_family_t	nl_family;	/* AF_NETLINK	*/
28 	unsigned short	nl_pad;		/* zero		*/
29 	__u32		nl_pid;		/* process pid	*/
30        	__u32		nl_groups;	/* multicast groups mask */
31 };
32 
33 struct nlmsghdr
34 {
35 	__u32		nlmsg_len;	/* Length of message including header */
36 	__u16		nlmsg_type;	/* Message content */
37 	__u16		nlmsg_flags;	/* Additional flags */
38 	__u32		nlmsg_seq;	/* Sequence number */
39 	__u32		nlmsg_pid;	/* Sending process PID */
40 };
41 
42 /* Flags values */
43 
44 #define NLM_F_REQUEST		1	/* It is request message. 	*/
45 #define NLM_F_MULTI		2	/* Multipart message, terminated by NLMSG_DONE */
46 #define NLM_F_ACK		4	/* Reply with ack, with zero or error code */
47 #define NLM_F_ECHO		8	/* Echo this request 		*/
48 
49 /* Modifiers to GET request */
50 #define NLM_F_ROOT	0x100	/* specify tree	root	*/
51 #define NLM_F_MATCH	0x200	/* return all matching	*/
52 #define NLM_F_ATOMIC	0x400	/* atomic GET		*/
53 #define NLM_F_DUMP	(NLM_F_ROOT|NLM_F_MATCH)
54 
55 /* Modifiers to NEW request */
56 #define NLM_F_REPLACE	0x100	/* Override existing		*/
57 #define NLM_F_EXCL	0x200	/* Do not touch, if it exists	*/
58 #define NLM_F_CREATE	0x400	/* Create, if it does not exist	*/
59 #define NLM_F_APPEND	0x800	/* Add to end of list		*/
60 
61 /*
62    4.4BSD ADD		NLM_F_CREATE|NLM_F_EXCL
63    4.4BSD CHANGE	NLM_F_REPLACE
64 
65    True CHANGE		NLM_F_CREATE|NLM_F_REPLACE
66    Append		NLM_F_CREATE
67    Check		NLM_F_EXCL
68  */
69 
70 #define NLMSG_ALIGNTO	4
71 #define NLMSG_ALIGN(len) ( ((len)+NLMSG_ALIGNTO-1) & ~(NLMSG_ALIGNTO-1) )
72 #define NLMSG_LENGTH(len) ((len)+NLMSG_ALIGN(sizeof(struct nlmsghdr)))
73 #define NLMSG_SPACE(len) NLMSG_ALIGN(NLMSG_LENGTH(len))
74 #define NLMSG_DATA(nlh)  ((void*)(((char*)nlh) + NLMSG_LENGTH(0)))
75 #define NLMSG_NEXT(nlh,len)	 ((len) -= NLMSG_ALIGN((nlh)->nlmsg_len), \
76 				  (struct nlmsghdr*)(((char*)(nlh)) + NLMSG_ALIGN((nlh)->nlmsg_len)))
77 #define NLMSG_OK(nlh,len) ((len) >= (int)sizeof(struct nlmsghdr) && \
78 			   (nlh)->nlmsg_len >= sizeof(struct nlmsghdr) && \
79 			   (nlh)->nlmsg_len <= (len))
80 #define NLMSG_PAYLOAD(nlh,len) ((nlh)->nlmsg_len - NLMSG_SPACE((len)))
81 
82 #define NLMSG_NOOP		0x1	/* Nothing.		*/
83 #define NLMSG_ERROR		0x2	/* Error		*/
84 #define NLMSG_DONE		0x3	/* End of a dump	*/
85 #define NLMSG_OVERRUN		0x4	/* Data lost		*/
86 
87 struct nlmsgerr
88 {
89 	int		error;
90 	struct nlmsghdr msg;
91 };
92 
93 #define NET_MAJOR 36		/* Major 36 is reserved for networking 						*/
94 
95 enum {
96 	NETLINK_UNCONNECTED = 0,
97 	NETLINK_CONNECTED,
98 };
99 
100 #ifdef __KERNEL__
101 
102 #include <linux/capability.h>
103 #include <linux/skbuff.h>
104 
105 struct netlink_skb_parms
106 {
107 	struct ucred		creds;		/* Skb credentials	*/
108 	__u32			pid;
109 	__u32			groups;
110 	__u32			dst_pid;
111 	__u32			dst_groups;
112 	kernel_cap_t		eff_cap;
113 	__u32			loginuid;	/* Login (audit) uid */
114 };
115 
116 #define NETLINK_CB(skb)		(*(struct netlink_skb_parms*)&((skb)->cb))
117 #define NETLINK_CREDS(skb)	(&NETLINK_CB((skb)).creds)
118 
119 
120 extern struct sock *netlink_kernel_create(int unit, void (*input)(struct sock *sk, int len));
121 extern void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err);
122 extern int netlink_unicast(struct sock *ssk, struct sk_buff *skb, __u32 pid, int nonblock);
123 extern int netlink_broadcast(struct sock *ssk, struct sk_buff *skb, __u32 pid,
124 			     __u32 group, int allocation);
125 extern void netlink_set_err(struct sock *ssk, __u32 pid, __u32 group, int code);
126 extern int netlink_register_notifier(struct notifier_block *nb);
127 extern int netlink_unregister_notifier(struct notifier_block *nb);
128 
129 /* finegrained unicast helpers: */
130 struct sock *netlink_getsockbyfilp(struct file *filp);
131 int netlink_attachskb(struct sock *sk, struct sk_buff *skb, int nonblock, long timeo);
132 void netlink_detachskb(struct sock *sk, struct sk_buff *skb);
133 int netlink_sendskb(struct sock *sk, struct sk_buff *skb, int protocol);
134 
135 /*
136  *	skb should fit one page. This choice is good for headerless malloc.
137  */
138 #define NLMSG_GOODORDER 0
139 #define NLMSG_GOODSIZE (SKB_MAX_ORDER(0, NLMSG_GOODORDER))
140 
141 
142 struct netlink_callback
143 {
144 	struct sk_buff	*skb;
145 	struct nlmsghdr	*nlh;
146 	int		(*dump)(struct sk_buff * skb, struct netlink_callback *cb);
147 	int		(*done)(struct netlink_callback *cb);
148 	int		family;
149 	long		args[4];
150 };
151 
152 struct netlink_notify
153 {
154 	int pid;
155 	int protocol;
156 };
157 
158 static __inline__ struct nlmsghdr *
159 __nlmsg_put(struct sk_buff *skb, u32 pid, u32 seq, int type, int len)
160 {
161 	struct nlmsghdr *nlh;
162 	int size = NLMSG_LENGTH(len);
163 
164 	nlh = (struct nlmsghdr*)skb_put(skb, NLMSG_ALIGN(size));
165 	nlh->nlmsg_type = type;
166 	nlh->nlmsg_len = size;
167 	nlh->nlmsg_flags = 0;
168 	nlh->nlmsg_pid = pid;
169 	nlh->nlmsg_seq = seq;
170 	return nlh;
171 }
172 
173 #define NLMSG_PUT(skb, pid, seq, type, len) \
174 ({ if (skb_tailroom(skb) < (int)NLMSG_SPACE(len)) goto nlmsg_failure; \
175    __nlmsg_put(skb, pid, seq, type, len); })
176 
177 extern int netlink_dump_start(struct sock *ssk, struct sk_buff *skb,
178 			      struct nlmsghdr *nlh,
179 			      int (*dump)(struct sk_buff *skb, struct netlink_callback*),
180 			      int (*done)(struct netlink_callback*));
181 
182 
183 #define NL_NONROOT_RECV 0x1
184 #define NL_NONROOT_SEND 0x2
185 extern void netlink_set_nonroot(int protocol, unsigned flag);
186 
187 #endif /* __KERNEL__ */
188 
189 #endif	/* __LINUX_NETLINK_H */
190