xref: /linux-6.15/include/linux/netlink.h (revision 4bedea94)
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_FIB_LOOKUP	10
18 #define NETLINK_ROUTE6		11	/* af_inet6 route comm channel */
19 #define NETLINK_IP6_FW		13
20 #define NETLINK_DNRTMSG		14	/* DECnet routing messages */
21 #define NETLINK_KOBJECT_UEVENT	15	/* Kernel messages to userspace */
22 #define NETLINK_TAPBASE		16	/* 16 to 31 are ethertap */
23 
24 #define MAX_LINKS 32
25 
26 struct sockaddr_nl
27 {
28 	sa_family_t	nl_family;	/* AF_NETLINK	*/
29 	unsigned short	nl_pad;		/* zero		*/
30 	__u32		nl_pid;		/* process pid	*/
31        	__u32		nl_groups;	/* multicast groups mask */
32 };
33 
34 struct nlmsghdr
35 {
36 	__u32		nlmsg_len;	/* Length of message including header */
37 	__u16		nlmsg_type;	/* Message content */
38 	__u16		nlmsg_flags;	/* Additional flags */
39 	__u32		nlmsg_seq;	/* Sequence number */
40 	__u32		nlmsg_pid;	/* Sending process PID */
41 };
42 
43 /* Flags values */
44 
45 #define NLM_F_REQUEST		1	/* It is request message. 	*/
46 #define NLM_F_MULTI		2	/* Multipart message, terminated by NLMSG_DONE */
47 #define NLM_F_ACK		4	/* Reply with ack, with zero or error code */
48 #define NLM_F_ECHO		8	/* Echo this request 		*/
49 
50 /* Modifiers to GET request */
51 #define NLM_F_ROOT	0x100	/* specify tree	root	*/
52 #define NLM_F_MATCH	0x200	/* return all matching	*/
53 #define NLM_F_ATOMIC	0x400	/* atomic GET		*/
54 #define NLM_F_DUMP	(NLM_F_ROOT|NLM_F_MATCH)
55 
56 /* Modifiers to NEW request */
57 #define NLM_F_REPLACE	0x100	/* Override existing		*/
58 #define NLM_F_EXCL	0x200	/* Do not touch, if it exists	*/
59 #define NLM_F_CREATE	0x400	/* Create, if it does not exist	*/
60 #define NLM_F_APPEND	0x800	/* Add to end of list		*/
61 
62 /*
63    4.4BSD ADD		NLM_F_CREATE|NLM_F_EXCL
64    4.4BSD CHANGE	NLM_F_REPLACE
65 
66    True CHANGE		NLM_F_CREATE|NLM_F_REPLACE
67    Append		NLM_F_CREATE
68    Check		NLM_F_EXCL
69  */
70 
71 #define NLMSG_ALIGNTO	4
72 #define NLMSG_ALIGN(len) ( ((len)+NLMSG_ALIGNTO-1) & ~(NLMSG_ALIGNTO-1) )
73 #define NLMSG_LENGTH(len) ((len)+NLMSG_ALIGN(sizeof(struct nlmsghdr)))
74 #define NLMSG_SPACE(len) NLMSG_ALIGN(NLMSG_LENGTH(len))
75 #define NLMSG_DATA(nlh)  ((void*)(((char*)nlh) + NLMSG_LENGTH(0)))
76 #define NLMSG_NEXT(nlh,len)	 ((len) -= NLMSG_ALIGN((nlh)->nlmsg_len), \
77 				  (struct nlmsghdr*)(((char*)(nlh)) + NLMSG_ALIGN((nlh)->nlmsg_len)))
78 #define NLMSG_OK(nlh,len) ((len) >= (int)sizeof(struct nlmsghdr) && \
79 			   (nlh)->nlmsg_len >= sizeof(struct nlmsghdr) && \
80 			   (nlh)->nlmsg_len <= (len))
81 #define NLMSG_PAYLOAD(nlh,len) ((nlh)->nlmsg_len - NLMSG_SPACE((len)))
82 
83 #define NLMSG_NOOP		0x1	/* Nothing.		*/
84 #define NLMSG_ERROR		0x2	/* Error		*/
85 #define NLMSG_DONE		0x3	/* End of a dump	*/
86 #define NLMSG_OVERRUN		0x4	/* Data lost		*/
87 
88 struct nlmsgerr
89 {
90 	int		error;
91 	struct nlmsghdr msg;
92 };
93 
94 #define NET_MAJOR 36		/* Major 36 is reserved for networking 						*/
95 
96 enum {
97 	NETLINK_UNCONNECTED = 0,
98 	NETLINK_CONNECTED,
99 };
100 
101 #ifdef __KERNEL__
102 
103 #include <linux/capability.h>
104 #include <linux/skbuff.h>
105 
106 struct netlink_skb_parms
107 {
108 	struct ucred		creds;		/* Skb credentials	*/
109 	__u32			pid;
110 	__u32			groups;
111 	__u32			dst_pid;
112 	__u32			dst_groups;
113 	kernel_cap_t		eff_cap;
114 	__u32			loginuid;	/* Login (audit) uid */
115 };
116 
117 #define NETLINK_CB(skb)		(*(struct netlink_skb_parms*)&((skb)->cb))
118 #define NETLINK_CREDS(skb)	(&NETLINK_CB((skb)).creds)
119 
120 
121 extern struct sock *netlink_kernel_create(int unit, void (*input)(struct sock *sk, int len));
122 extern void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err);
123 extern int netlink_unicast(struct sock *ssk, struct sk_buff *skb, __u32 pid, int nonblock);
124 extern int netlink_broadcast(struct sock *ssk, struct sk_buff *skb, __u32 pid,
125 			     __u32 group, int allocation);
126 extern void netlink_set_err(struct sock *ssk, __u32 pid, __u32 group, int code);
127 extern int netlink_register_notifier(struct notifier_block *nb);
128 extern int netlink_unregister_notifier(struct notifier_block *nb);
129 
130 /* finegrained unicast helpers: */
131 struct sock *netlink_getsockbyfilp(struct file *filp);
132 int netlink_attachskb(struct sock *sk, struct sk_buff *skb, int nonblock, long timeo);
133 void netlink_detachskb(struct sock *sk, struct sk_buff *skb);
134 int netlink_sendskb(struct sock *sk, struct sk_buff *skb, int protocol);
135 
136 /*
137  *	skb should fit one page. This choice is good for headerless malloc.
138  */
139 #define NLMSG_GOODORDER 0
140 #define NLMSG_GOODSIZE (SKB_MAX_ORDER(0, NLMSG_GOODORDER))
141 
142 
143 struct netlink_callback
144 {
145 	struct sk_buff	*skb;
146 	struct nlmsghdr	*nlh;
147 	int		(*dump)(struct sk_buff * skb, struct netlink_callback *cb);
148 	int		(*done)(struct netlink_callback *cb);
149 	int		family;
150 	long		args[5];
151 };
152 
153 struct netlink_notify
154 {
155 	int pid;
156 	int protocol;
157 };
158 
159 static __inline__ struct nlmsghdr *
160 __nlmsg_put(struct sk_buff *skb, u32 pid, u32 seq, int type, int len, int flags)
161 {
162 	struct nlmsghdr *nlh;
163 	int size = NLMSG_LENGTH(len);
164 
165 	nlh = (struct nlmsghdr*)skb_put(skb, NLMSG_ALIGN(size));
166 	nlh->nlmsg_type = type;
167 	nlh->nlmsg_len = size;
168 	nlh->nlmsg_flags = flags;
169 	nlh->nlmsg_pid = pid;
170 	nlh->nlmsg_seq = seq;
171 	return nlh;
172 }
173 
174 #define NLMSG_NEW(skb, pid, seq, type, len, flags) \
175 ({	if (skb_tailroom(skb) < (int)NLMSG_SPACE(len)) \
176 		goto nlmsg_failure; \
177 	__nlmsg_put(skb, pid, seq, type, len, flags); })
178 
179 #define NLMSG_PUT(skb, pid, seq, type, len) \
180 	NLMSG_NEW(skb, pid, seq, type, len, 0)
181 
182 #define NLMSG_NEW_ANSWER(skb, cb, type, len, flags) \
183 	NLMSG_NEW(skb, NETLINK_CB((cb)->skb).pid, \
184 		  (cb)->nlh->nlmsg_seq, type, len, flags)
185 
186 #define NLMSG_END(skb, nlh) \
187 ({	(nlh)->nlmsg_len = (skb)->tail - (unsigned char *) (nlh); \
188 	(skb)->len; })
189 
190 #define NLMSG_CANCEL(skb, nlh) \
191 ({	skb_trim(skb, (unsigned char *) (nlh) - (skb)->data); \
192 	-1; })
193 
194 extern int netlink_dump_start(struct sock *ssk, struct sk_buff *skb,
195 			      struct nlmsghdr *nlh,
196 			      int (*dump)(struct sk_buff *skb, struct netlink_callback*),
197 			      int (*done)(struct netlink_callback*));
198 
199 
200 #define NL_NONROOT_RECV 0x1
201 #define NL_NONROOT_SEND 0x2
202 extern void netlink_set_nonroot(int protocol, unsigned flag);
203 
204 #endif /* __KERNEL__ */
205 
206 #endif	/* __LINUX_NETLINK_H */
207