1#ifndef __LINUX_NETLINK_H
2#define __LINUX_NETLINK_H
3
4
5#include <linux/capability.h>
6#include <linux/skbuff.h>
7#include <linux/export.h>
8#include <net/scm.h>
9#include <uapi/linux/netlink.h>
10
11struct net;
12
13static inline struct nlmsghdr *nlmsg_hdr(const struct sk_buff *skb)
14{
15	return (struct nlmsghdr *)skb->data;
16}
17
18enum netlink_skb_flags {
19	NETLINK_SKB_MMAPED	= 0x1,	/* Packet data is mmaped */
20	NETLINK_SKB_TX		= 0x2,	/* Packet was sent by userspace */
21	NETLINK_SKB_DELIVERED	= 0x4,	/* Packet was delivered */
22	NETLINK_SKB_DST		= 0x8,	/* Dst set in sendto or sendmsg */
23};
24
25struct netlink_skb_parms {
26	struct scm_creds	creds;		/* Skb credentials	*/
27	__u32			portid;
28	__u32			dst_group;
29	__u32			flags;
30	struct sock		*sk;
31};
32
33#define NETLINK_CB(skb)		(*(struct netlink_skb_parms*)&((skb)->cb))
34#define NETLINK_CREDS(skb)	(&NETLINK_CB((skb)).creds)
35
36
37extern void netlink_table_grab(void);
38extern void netlink_table_ungrab(void);
39
40#define NL_CFG_F_NONROOT_RECV	(1 << 0)
41#define NL_CFG_F_NONROOT_SEND	(1 << 1)
42
43/* optional Netlink kernel configuration parameters */
44struct netlink_kernel_cfg {
45	unsigned int	groups;
46	unsigned int	flags;
47	void		(*input)(struct sk_buff *skb);
48	struct mutex	*cb_mutex;
49	int		(*bind)(struct net *net, int group);
50	void		(*unbind)(struct net *net, int group);
51	bool		(*compare)(struct net *net, struct sock *sk);
52};
53
54extern struct sock *__netlink_kernel_create(struct net *net, int unit,
55					    struct module *module,
56					    struct netlink_kernel_cfg *cfg);
57static inline struct sock *
58netlink_kernel_create(struct net *net, int unit, struct netlink_kernel_cfg *cfg)
59{
60	return __netlink_kernel_create(net, unit, THIS_MODULE, cfg);
61}
62
63extern void netlink_kernel_release(struct sock *sk);
64extern int __netlink_change_ngroups(struct sock *sk, unsigned int groups);
65extern int netlink_change_ngroups(struct sock *sk, unsigned int groups);
66extern void __netlink_clear_multicast_users(struct sock *sk, unsigned int group);
67extern void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err);
68extern int netlink_has_listeners(struct sock *sk, unsigned int group);
69extern struct sk_buff *netlink_alloc_skb(struct sock *ssk, unsigned int size,
70					 u32 dst_portid, gfp_t gfp_mask);
71extern int netlink_unicast(struct sock *ssk, struct sk_buff *skb, __u32 portid, int nonblock);
72extern int netlink_broadcast(struct sock *ssk, struct sk_buff *skb, __u32 portid,
73			     __u32 group, gfp_t allocation);
74extern int netlink_broadcast_filtered(struct sock *ssk, struct sk_buff *skb,
75	__u32 portid, __u32 group, gfp_t allocation,
76	int (*filter)(struct sock *dsk, struct sk_buff *skb, void *data),
77	void *filter_data);
78extern int netlink_set_err(struct sock *ssk, __u32 portid, __u32 group, int code);
79extern int netlink_register_notifier(struct notifier_block *nb);
80extern int netlink_unregister_notifier(struct notifier_block *nb);
81
82/* finegrained unicast helpers: */
83struct sock *netlink_getsockbyfilp(struct file *filp);
84int netlink_attachskb(struct sock *sk, struct sk_buff *skb,
85		      long *timeo, struct sock *ssk);
86void netlink_detachskb(struct sock *sk, struct sk_buff *skb);
87int netlink_sendskb(struct sock *sk, struct sk_buff *skb);
88
89static inline struct sk_buff *
90netlink_skb_clone(struct sk_buff *skb, gfp_t gfp_mask)
91{
92	struct sk_buff *nskb;
93
94	nskb = skb_clone(skb, gfp_mask);
95	if (!nskb)
96		return NULL;
97
98	/* This is a large skb, set destructor callback to release head */
99	if (is_vmalloc_addr(skb->head))
100		nskb->destructor = skb->destructor;
101
102	return nskb;
103}
104
105/*
106 *	skb should fit one page. This choice is good for headerless malloc.
107 *	But we should limit to 8K so that userspace does not have to
108 *	use enormous buffer sizes on recvmsg() calls just to avoid
109 *	MSG_TRUNC when PAGE_SIZE is very large.
110 */
111#if PAGE_SIZE < 8192UL
112#define NLMSG_GOODSIZE	SKB_WITH_OVERHEAD(PAGE_SIZE)
113#else
114#define NLMSG_GOODSIZE	SKB_WITH_OVERHEAD(8192UL)
115#endif
116
117#define NLMSG_DEFAULT_SIZE (NLMSG_GOODSIZE - NLMSG_HDRLEN)
118
119
120struct netlink_callback {
121	struct sk_buff		*skb;
122	const struct nlmsghdr	*nlh;
123	int			(*dump)(struct sk_buff * skb,
124					struct netlink_callback *cb);
125	int			(*done)(struct netlink_callback *cb);
126	void			*data;
127	/* the module that dump function belong to */
128	struct module		*module;
129	u16			family;
130	u16			min_dump_alloc;
131	unsigned int		prev_seq, seq;
132	long			args[6];
133};
134
135struct netlink_notify {
136	struct net *net;
137	u32 portid;
138	int protocol;
139};
140
141struct nlmsghdr *
142__nlmsg_put(struct sk_buff *skb, u32 portid, u32 seq, int type, int len, int flags);
143
144struct netlink_dump_control {
145	int (*dump)(struct sk_buff *skb, struct netlink_callback *);
146	int (*done)(struct netlink_callback *);
147	void *data;
148	struct module *module;
149	u16 min_dump_alloc;
150};
151
152extern int __netlink_dump_start(struct sock *ssk, struct sk_buff *skb,
153				const struct nlmsghdr *nlh,
154				struct netlink_dump_control *control);
155static inline int netlink_dump_start(struct sock *ssk, struct sk_buff *skb,
156				     const struct nlmsghdr *nlh,
157				     struct netlink_dump_control *control)
158{
159	if (!control->module)
160		control->module = THIS_MODULE;
161
162	return __netlink_dump_start(ssk, skb, nlh, control);
163}
164
165struct netlink_tap {
166	struct net_device *dev;
167	struct module *module;
168	struct list_head list;
169};
170
171extern int netlink_add_tap(struct netlink_tap *nt);
172extern int netlink_remove_tap(struct netlink_tap *nt);
173
174bool __netlink_ns_capable(const struct netlink_skb_parms *nsp,
175			  struct user_namespace *ns, int cap);
176bool netlink_ns_capable(const struct sk_buff *skb,
177			struct user_namespace *ns, int cap);
178bool netlink_capable(const struct sk_buff *skb, int cap);
179bool netlink_net_capable(const struct sk_buff *skb, int cap);
180
181#endif	/* __LINUX_NETLINK_H */
182