[mirror_ubuntu-focal-kernel.git] / include / linux / netlink.h

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef __LINUX_NETLINK_H
#define __LINUX_NETLINK_H


#include <linux/capability.h>
#include <linux/skbuff.h>
#include <linux/export.h>
#include <net/scm.h>
#include <uapi/linux/netlink.h>

struct net;

static inline struct nlmsghdr *nlmsg_hdr(const struct sk_buff *skb)
{
	return (struct nlmsghdr *)skb->data;
}

enum netlink_skb_flags {
	NETLINK_SKB_MMAPED	= 0x1,	/* Packet data is mmaped */
	NETLINK_SKB_TX		= 0x2,	/* Packet was sent by userspace */
	NETLINK_SKB_DELIVERED	= 0x4,	/* Packet was delivered */
	NETLINK_SKB_DST		= 0x8,	/* Dst set in sendto or sendmsg */
};

struct netlink_skb_parms {
	struct scm_creds	creds;		/* Skb credentials	*/
	__u32			portid;
	__u32			dst_group;
	__u32			flags;
	struct sock		*sk;
	bool			nsid_is_set;
	int			nsid;
};

#define NETLINK_CB(skb)		(*(struct netlink_skb_parms*)&((skb)->cb))
#define NETLINK_CREDS(skb)	(&NETLINK_CB((skb)).creds)


extern void netlink_table_grab(void);
extern void netlink_table_ungrab(void);

#define NL_CFG_F_NONROOT_RECV	(1 << 0)
#define NL_CFG_F_NONROOT_SEND	(1 << 1)

/* optional Netlink kernel configuration parameters */
struct netlink_kernel_cfg {
	unsigned int	groups;
	unsigned int	flags;
	void		(*input)(struct sk_buff *skb);
	struct mutex	*cb_mutex;
	int		(*bind)(struct net *net, int group);
	void		(*unbind)(struct net *net, int group);
	bool		(*compare)(struct net *net, struct sock *sk);
};

extern struct sock *__netlink_kernel_create(struct net *net, int unit,
					    struct module *module,
					    struct netlink_kernel_cfg *cfg);
static inline struct sock *
netlink_kernel_create(struct net *net, int unit, struct netlink_kernel_cfg *cfg)
{
	return __netlink_kernel_create(net, unit, THIS_MODULE, cfg);
}

/* this can be increased when necessary - don't expose to userland */
#define NETLINK_MAX_COOKIE_LEN	20

/**
 * struct netlink_ext_ack - netlink extended ACK report struct
 * @_msg: message string to report - don't access directly, use
 *	%NL_SET_ERR_MSG
 * @bad_attr: attribute with error
 * @cookie: cookie data to return to userspace (for success)
 * @cookie_len: actual cookie data length
 */
struct netlink_ext_ack {
	const char *_msg;
	const struct nlattr *bad_attr;
	u8 cookie[NETLINK_MAX_COOKIE_LEN];
	u8 cookie_len;
};

/* Always use this macro, this allows later putting the
 * message into a separate section or such for things
 * like translation or listing all possible messages.
 * Currently string formatting is not supported (due
 * to the lack of an output buffer.)
 */
#define NL_SET_ERR_MSG(extack, msg) do {		\
	static const char __msg[] = (msg);		\
	struct netlink_ext_ack *__extack = (extack);	\
							\
	if (__extack)					\
		__extack->_msg = __msg;			\
} while (0)

#define NL_SET_ERR_MSG_MOD(extack, msg)			\
	NL_SET_ERR_MSG((extack), KBUILD_MODNAME ": " msg)

#define NL_SET_BAD_ATTR(extack, attr) do {		\
	if ((extack))					\
		(extack)->bad_attr = (attr);		\
} while (0)

#define NL_SET_ERR_MSG_ATTR(extack, attr, msg) do {	\
	static const char __msg[] = (msg);		\
	struct netlink_ext_ack *__extack = (extack);	\
							\
	if (__extack) {					\
		__extack->_msg = __msg;			\
		__extack->bad_attr = (attr);		\
	}						\
} while (0)

extern void netlink_kernel_release(struct sock *sk);
extern int __netlink_change_ngroups(struct sock *sk, unsigned int groups);
extern int netlink_change_ngroups(struct sock *sk, unsigned int groups);
extern void __netlink_clear_multicast_users(struct sock *sk, unsigned int group);
extern void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err,
			const struct netlink_ext_ack *extack);
extern int netlink_has_listeners(struct sock *sk, unsigned int group);

extern int netlink_unicast(struct sock *ssk, struct sk_buff *skb, __u32 portid, int nonblock);
extern int netlink_broadcast(struct sock *ssk, struct sk_buff *skb, __u32 portid,
			     __u32 group, gfp_t allocation);
extern int netlink_broadcast_filtered(struct sock *ssk, struct sk_buff *skb,
	__u32 portid, __u32 group, gfp_t allocation,
	int (*filter)(struct sock *dsk, struct sk_buff *skb, void *data),
	void *filter_data);
extern int netlink_set_err(struct sock *ssk, __u32 portid, __u32 group, int code);
extern int netlink_register_notifier(struct notifier_block *nb);
extern int netlink_unregister_notifier(struct notifier_block *nb);

/* finegrained unicast helpers: */
struct sock *netlink_getsockbyfilp(struct file *filp);
int netlink_attachskb(struct sock *sk, struct sk_buff *skb,
		      long *timeo, struct sock *ssk);
void netlink_detachskb(struct sock *sk, struct sk_buff *skb);
int netlink_sendskb(struct sock *sk, struct sk_buff *skb);

static inline struct sk_buff *
netlink_skb_clone(struct sk_buff *skb, gfp_t gfp_mask)
{
	struct sk_buff *nskb;

	nskb = skb_clone(skb, gfp_mask);
	if (!nskb)
		return NULL;

	/* This is a large skb, set destructor callback to release head */
	if (is_vmalloc_addr(skb->head))
		nskb->destructor = skb->destructor;

	return nskb;
}

/*
 *	skb should fit one page. This choice is good for headerless malloc.
 *	But we should limit to 8K so that userspace does not have to
 *	use enormous buffer sizes on recvmsg() calls just to avoid
 *	MSG_TRUNC when PAGE_SIZE is very large.
 */
#if PAGE_SIZE < 8192UL
#define NLMSG_GOODSIZE	SKB_WITH_OVERHEAD(PAGE_SIZE)
#else
#define NLMSG_GOODSIZE	SKB_WITH_OVERHEAD(8192UL)
#endif

#define NLMSG_DEFAULT_SIZE (NLMSG_GOODSIZE - NLMSG_HDRLEN)


struct netlink_callback {
	struct sk_buff		*skb;
	const struct nlmsghdr	*nlh;
	int			(*start)(struct netlink_callback *);
	int			(*dump)(struct sk_buff * skb,
					struct netlink_callback *cb);
	int			(*done)(struct netlink_callback *cb);
	void			*data;
	/* the module that dump function belong to */
	struct module		*module;
	u16			family;
	u16			min_dump_alloc;
	unsigned int		prev_seq, seq;
	long			args[6];
};

struct netlink_notify {
	struct net *net;
	u32 portid;
	int protocol;
};

struct nlmsghdr *
__nlmsg_put(struct sk_buff *skb, u32 portid, u32 seq, int type, int len, int flags);

struct netlink_dump_control {
	int (*start)(struct netlink_callback *);
	int (*dump)(struct sk_buff *skb, struct netlink_callback *);
	int (*done)(struct netlink_callback *);
	void *data;
	struct module *module;
	u16 min_dump_alloc;
};

extern int __netlink_dump_start(struct sock *ssk, struct sk_buff *skb,
				const struct nlmsghdr *nlh,
				struct netlink_dump_control *control);
static inline int netlink_dump_start(struct sock *ssk, struct sk_buff *skb,
				     const struct nlmsghdr *nlh,
				     struct netlink_dump_control *control)
{
	if (!control->module)
		control->module = THIS_MODULE;

	return __netlink_dump_start(ssk, skb, nlh, control);
}

struct netlink_tap {
	struct net_device *dev;
	struct module *module;
	struct list_head list;
};

extern int netlink_add_tap(struct netlink_tap *nt);
extern int netlink_remove_tap(struct netlink_tap *nt);

bool __netlink_ns_capable(const struct netlink_skb_parms *nsp,
			  struct user_namespace *ns, int cap);
bool netlink_ns_capable(const struct sk_buff *skb,
			struct user_namespace *ns, int cap);
bool netlink_capable(const struct sk_buff *skb, int cap);
bool netlink_net_capable(const struct sk_buff *skb, int cap);

#endif	/* __LINUX_NETLINK_H */
Commit	Line	Data
b2441318	1	/* SPDX-License-Identifier: GPL-2.0 */
1da177e4 LT	2	#ifndef __LINUX_NETLINK_H
	3	#define __LINUX_NETLINK_H
	4
1da177e4 LT	5
	6	#include <linux/capability.h>
	7	#include <linux/skbuff.h>
abb17e6c	8	#include <linux/export.h>
dbe9a417	9	#include <net/scm.h>
607ca46e	10	#include <uapi/linux/netlink.h>
1da177e4	11
56b49f4b OW	12	struct net;
56b49f4b OW	13
b529ccf2 ACM	14	static inline struct nlmsghdr nlmsg_hdr(const struct sk_buff skb)
	15	{
	16	return (struct nlmsghdr *)skb->data;
	17	}
	18
9652e931	19	enum netlink_skb_flags {
2d7a85f4 EB	20	NETLINK_SKB_MMAPED = 0x1, /* Packet data is mmaped */
	21	NETLINK_SKB_TX = 0x2, /* Packet was sent by userspace */
	22	NETLINK_SKB_DELIVERED = 0x4, /* Packet was delivered */
	23	NETLINK_SKB_DST = 0x8, /* Dst set in sendto or sendmsg */
9652e931 PM	24	};
9652e931 PM	25
d94d9fee	26	struct netlink_skb_parms {
dbe9a417	27	struct scm_creds creds; /* Skb credentials */
15e47304	28	__u32 portid;
d629b836	29	__u32 dst_group;
9652e931	30	__u32 flags;
e32123e5	31	struct sock *sk;
59324cf3 ND	32	bool nsid_is_set;
59324cf3 ND	33	int nsid;
1da177e4 LT	34	};
	35
	36	#define NETLINK_CB(skb) ((struct netlink_skb_parms)&((skb)->cb))
	37	#define NETLINK_CREDS(skb) (&NETLINK_CB((skb)).creds)
	38
	39
d136f1bd JB	40	extern void netlink_table_grab(void);
	41	extern void netlink_table_ungrab(void);
	42
9785e10a PNA	43	#define NL_CFG_F_NONROOT_RECV (1 << 0)
	44	#define NL_CFG_F_NONROOT_SEND (1 << 1)
	45
a31f2d17 PNA	46	/* optional Netlink kernel configuration parameters */
	47	struct netlink_kernel_cfg {
	48	unsigned int groups;
c9d2ea96	49	unsigned int flags;
a31f2d17 PNA	50	void (input)(struct sk_buff skb);
a31f2d17 PNA	51	struct mutex *cb_mutex;
023e2cfa JB	52	int (bind)(struct net net, int group);
023e2cfa JB	53	void (unbind)(struct net net, int group);
da12c90e	54	bool (compare)(struct net net, struct sock *sk);
a31f2d17 PNA	55	};
a31f2d17 PNA	56
9f00d977 PNA	57	extern struct sock __netlink_kernel_create(struct net net, int unit,
	58	struct module *module,
	59	struct netlink_kernel_cfg *cfg);
	60	static inline struct sock *
	61	netlink_kernel_create(struct net net, int unit, struct netlink_kernel_cfg cfg)
	62	{
	63	return __netlink_kernel_create(net, unit, THIS_MODULE, cfg);
	64	}
	65
ba0dc5f6 JB	66	/* this can be increased when necessary - don't expose to userland */
	67	#define NETLINK_MAX_COOKIE_LEN 20
	68
2d4bc933 JB	69	/**
	70	* struct netlink_ext_ack - netlink extended ACK report struct
	71	* @_msg: message string to report - don't access directly, use
	72	* %NL_SET_ERR_MSG
	73	* @bad_attr: attribute with error
ba0dc5f6 JB	74	* @cookie: cookie data to return to userspace (for success)
ba0dc5f6 JB	75	* @cookie_len: actual cookie data length
2d4bc933 JB	76	*/
	77	struct netlink_ext_ack {
	78	const char *_msg;
	79	const struct nlattr *bad_attr;
ba0dc5f6 JB	80	u8 cookie[NETLINK_MAX_COOKIE_LEN];
ba0dc5f6 JB	81	u8 cookie_len;
2d4bc933 JB	82	};
	83
	84	/* Always use this macro, this allows later putting the
	85	* message into a separate section or such for things
	86	* like translation or listing all possible messages.
	87	* Currently string formatting is not supported (due
	88	* to the lack of an output buffer.)
	89	*/
4d463c4d DB	90	#define NL_SET_ERR_MSG(extack, msg) do { \
	91	static const char __msg[] = (msg); \
	92	struct netlink_ext_ack *__extack = (extack); \
	93	\
	94	if (__extack) \
	95	__extack->_msg = __msg; \
2d4bc933 JB	96	} while (0)
2d4bc933 JB	97
4d463c4d DB	98	#define NL_SET_ERR_MSG_MOD(extack, msg) \
4d463c4d DB	99	NL_SET_ERR_MSG((extack), KBUILD_MODNAME ": " msg)
45d9b378	100
c3ab2b4e DA	101	#define NL_SET_BAD_ATTR(extack, attr) do { \
	102	if ((extack)) \
	103	(extack)->bad_attr = (attr); \
	104	} while (0)
	105
9ae28727 DA	106	#define NL_SET_ERR_MSG_ATTR(extack, attr, msg) do { \
	107	static const char __msg[] = (msg); \
	108	struct netlink_ext_ack *__extack = (extack); \
	109	\
	110	if (__extack) { \
	111	__extack->_msg = __msg; \
	112	__extack->bad_attr = (attr); \
	113	} \
	114	} while (0)
	115
b7c6ba6e	116	extern void netlink_kernel_release(struct sock *sk);
d136f1bd	117	extern int __netlink_change_ngroups(struct sock *sk, unsigned int groups);
b4ff4f04	118	extern int netlink_change_ngroups(struct sock *sk, unsigned int groups);
b8273570	119	extern void __netlink_clear_multicast_users(struct sock *sk, unsigned int group);
2d4bc933 JB	120	extern void netlink_ack(struct sk_buff in_skb, struct nlmsghdr nlh, int err,
2d4bc933 JB	121	const struct netlink_ext_ack *extack);
4277a083	122	extern int netlink_has_listeners(struct sock *sk, unsigned int group);
6bb0fef4	123
15e47304 EB	124	extern int netlink_unicast(struct sock ssk, struct sk_buff skb, __u32 portid, int nonblock);
15e47304 EB	125	extern int netlink_broadcast(struct sock ssk, struct sk_buff skb, __u32 portid,
dd0fc66f	126	__u32 group, gfp_t allocation);
910a7e90	127	extern int netlink_broadcast_filtered(struct sock ssk, struct sk_buff skb,
15e47304	128	__u32 portid, __u32 group, gfp_t allocation,
910a7e90 EB	129	int (filter)(struct sock dsk, struct sk_buff skb, void data),
910a7e90 EB	130	void *filter_data);
15e47304	131	extern int netlink_set_err(struct sock *ssk, __u32 portid, __u32 group, int code);
1da177e4 LT	132	extern int netlink_register_notifier(struct notifier_block *nb);
	133	extern int netlink_unregister_notifier(struct notifier_block *nb);
	134
	135	/* finegrained unicast helpers: */
	136	struct sock netlink_getsockbyfilp(struct file filp);
9457afee	137	int netlink_attachskb(struct sock sk, struct sk_buff skb,
c3d8d1e3	138	long timeo, struct sock ssk);
1da177e4	139	void netlink_detachskb(struct sock sk, struct sk_buff skb);
7ee015e0	140	int netlink_sendskb(struct sock sk, struct sk_buff skb);
1da177e4	141
3a36515f PN	142	static inline struct sk_buff *
	143	netlink_skb_clone(struct sk_buff *skb, gfp_t gfp_mask)
	144	{
	145	struct sk_buff *nskb;
	146
	147	nskb = skb_clone(skb, gfp_mask);
	148	if (!nskb)
	149	return NULL;
	150
	151	/* This is a large skb, set destructor callback to release head */
	152	if (is_vmalloc_addr(skb->head))
	153	nskb->destructor = skb->destructor;
	154
	155	return nskb;
	156	}
	157
1da177e4 LT	158	/*
1da177e4 LT	159	* skb should fit one page. This choice is good for headerless malloc.
fc910a27 DM	160	* But we should limit to 8K so that userspace does not have to
	161	* use enormous buffer sizes on recvmsg() calls just to avoid
	162	* MSG_TRUNC when PAGE_SIZE is very large.
1da177e4	163	*/
fc910a27 DM	164	#if PAGE_SIZE < 8192UL
	165	#define NLMSG_GOODSIZE SKB_WITH_OVERHEAD(PAGE_SIZE)
	166	#else
	167	#define NLMSG_GOODSIZE SKB_WITH_OVERHEAD(8192UL)
	168	#endif
	169
339bf98f	170	#define NLMSG_DEFAULT_SIZE (NLMSG_GOODSIZE - NLMSG_HDRLEN)
1da177e4 LT	171
1da177e4 LT	172
d94d9fee	173	struct netlink_callback {
3a6c2b41 PM	174	struct sk_buff *skb;
3a6c2b41 PM	175	const struct nlmsghdr *nlh;
fc9e50f5	176	int (start)(struct netlink_callback );
3a6c2b41 PM	177	int (dump)(struct sk_buff skb,
	178	struct netlink_callback *cb);
	179	int (done)(struct netlink_callback cb);
7175c883	180	void *data;
6dc878a8 G	181	/* the module that dump function belong to */
6dc878a8 G	182	struct module *module;
c7ac8679 GR	183	u16 family;
c7ac8679 GR	184	u16 min_dump_alloc;
670dc283	185	unsigned int prev_seq, seq;
3a6c2b41	186	long args[6];
1da177e4 LT	187	};
1da177e4 LT	188
d94d9fee	189	struct netlink_notify {
b4b51029	190	struct net *net;
0392d099	191	u32 portid;
1da177e4 LT	192	int protocol;
	193	};
	194
a46621a3	195	struct nlmsghdr *
15e47304	196	__nlmsg_put(struct sk_buff *skb, u32 portid, u32 seq, int type, int len, int flags);
1da177e4	197
80d326fa	198	struct netlink_dump_control {
fc9e50f5	199	int (start)(struct netlink_callback );
80d326fa	200	int (dump)(struct sk_buff skb, struct netlink_callback *);
6dc878a8	201	int (done)(struct netlink_callback );
7175c883	202	void *data;
6dc878a8	203	struct module *module;
80d326fa PNA	204	u16 min_dump_alloc;
	205	};
	206
6dc878a8 G	207	extern int __netlink_dump_start(struct sock ssk, struct sk_buff skb,
	208	const struct nlmsghdr *nlh,
	209	struct netlink_dump_control *control);
	210	static inline int netlink_dump_start(struct sock ssk, struct sk_buff skb,
	211	const struct nlmsghdr *nlh,
	212	struct netlink_dump_control *control)
	213	{
	214	if (!control->module)
	215	control->module = THIS_MODULE;
	216
	217	return __netlink_dump_start(ssk, skb, nlh, control);
	218	}
1da177e4	219
bcbde0d4 DB	220	struct netlink_tap {
	221	struct net_device *dev;
	222	struct module *module;
	223	struct list_head list;
	224	};
	225
	226	extern int netlink_add_tap(struct netlink_tap *nt);
bcbde0d4 DB	227	extern int netlink_remove_tap(struct netlink_tap *nt);
bcbde0d4 DB	228
aa4cf945 EB	229	bool __netlink_ns_capable(const struct netlink_skb_parms *nsp,
	230	struct user_namespace *ns, int cap);
	231	bool netlink_ns_capable(const struct sk_buff *skb,
	232	struct user_namespace *ns, int cap);
	233	bool netlink_capable(const struct sk_buff *skb, int cap);
	234	bool netlink_net_capable(const struct sk_buff *skb, int cap);
	235
1da177e4	236	#endif /* __LINUX_NETLINK_H */