[linux-block.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;

void do_trace_netlink_extack(const char *msg);

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

enum netlink_skb_flags {
	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)


void netlink_table_grab(void);
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);
};

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
 * @policy: policy for a bad attribute
 * @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;
	const struct nla_policy *policy;
	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);	\
							\
	do_trace_netlink_extack(__msg);			\
							\
	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_POLICY(extack, attr, pol) do {	\
	if ((extack)) {					\
		(extack)->bad_attr = (attr);		\
		(extack)->policy = (pol);		\
	}						\
} while (0)

#define NL_SET_BAD_ATTR(extack, attr) NL_SET_BAD_ATTR_POLICY(extack, attr, NULL)

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

#define NL_SET_ERR_MSG_ATTR(extack, attr, msg)		\
	NL_SET_ERR_MSG_ATTR_POL(extack, attr, NULL, msg)

static inline void nl_set_extack_cookie_u64(struct netlink_ext_ack *extack,
					    u64 cookie)
{
	if (!extack)
		return;
	memcpy(extack->cookie, &cookie, sizeof(cookie));
	extack->cookie_len = sizeof(cookie);
}

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

int netlink_unicast(struct sock *ssk, struct sk_buff *skb, __u32 portid, int nonblock);
int netlink_broadcast(struct sock *ssk, struct sk_buff *skb, __u32 portid,
		      __u32 group, gfp_t allocation);
int netlink_set_err(struct sock *ssk, __u32 portid, __u32 group, int code);
int netlink_register_notifier(struct notifier_block *nb);
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			(*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;
	struct netlink_ext_ack	*extack;
	u16			family;
	u16			answer_flags;
	u32			min_dump_alloc;
	unsigned int		prev_seq, seq;
	bool			strict_check;
	union {
		u8		ctx[48];

		/* args is deprecated. Cast a struct over ctx instead
		 * for proper type safety.
		 */
		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;
	u32 min_dump_alloc;
};

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;
};

int netlink_add_tap(struct netlink_tap *nt);
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
7e3ce05e MRL	14	void do_trace_netlink_extack(const char *msg);
7e3ce05e MRL	15
b529ccf2 ACM	16	static inline struct nlmsghdr nlmsg_hdr(const struct sk_buff skb)
	17	{
	18	return (struct nlmsghdr *)skb->data;
	19	}
	20
9652e931	21	enum netlink_skb_flags {
2d7a85f4	22	NETLINK_SKB_DST = 0x8, /* Dst set in sendto or sendmsg */
9652e931 PM	23	};
9652e931 PM	24
d94d9fee	25	struct netlink_skb_parms {
dbe9a417	26	struct scm_creds creds; /* Skb credentials */
15e47304	27	__u32 portid;
d629b836	28	__u32 dst_group;
9652e931	29	__u32 flags;
e32123e5	30	struct sock *sk;
59324cf3 ND	31	bool nsid_is_set;
59324cf3 ND	32	int nsid;
1da177e4 LT	33	};
	34
	35	#define NETLINK_CB(skb) ((struct netlink_skb_parms)&((skb)->cb))
	36	#define NETLINK_CREDS(skb) (&NETLINK_CB((skb)).creds)
	37
	38
aa9d6e0f SH	39	void netlink_table_grab(void);
aa9d6e0f SH	40	void netlink_table_ungrab(void);
d136f1bd	41
9785e10a PNA	42	#define NL_CFG_F_NONROOT_RECV (1 << 0)
	43	#define NL_CFG_F_NONROOT_SEND (1 << 1)
	44
a31f2d17 PNA	45	/* optional Netlink kernel configuration parameters */
	46	struct netlink_kernel_cfg {
	47	unsigned int groups;
c9d2ea96	48	unsigned int flags;
a31f2d17 PNA	49	void (input)(struct sk_buff skb);
a31f2d17 PNA	50	struct mutex *cb_mutex;
023e2cfa JB	51	int (bind)(struct net net, int group);
023e2cfa JB	52	void (unbind)(struct net net, int group);
da12c90e	53	bool (compare)(struct net net, struct sock *sk);
a31f2d17 PNA	54	};
a31f2d17 PNA	55
aa9d6e0f	56	struct sock __netlink_kernel_create(struct net net, int unit,
9f00d977 PNA	57	struct module *module,
	58	struct netlink_kernel_cfg *cfg);
	59	static inline struct sock *
	60	netlink_kernel_create(struct net net, int unit, struct netlink_kernel_cfg cfg)
	61	{
	62	return __netlink_kernel_create(net, unit, THIS_MODULE, cfg);
	63	}
	64
ba0dc5f6 JB	65	/* this can be increased when necessary - don't expose to userland */
	66	#define NETLINK_MAX_COOKIE_LEN 20
	67
2d4bc933 JB	68	/**
	69	* struct netlink_ext_ack - netlink extended ACK report struct
	70	* @_msg: message string to report - don't access directly, use
	71	* %NL_SET_ERR_MSG
	72	* @bad_attr: attribute with error
44f3625b	73	* @policy: policy for a bad attribute
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;
44f3625b	80	const struct nla_policy *policy;
ba0dc5f6 JB	81	u8 cookie[NETLINK_MAX_COOKIE_LEN];
ba0dc5f6 JB	82	u8 cookie_len;
2d4bc933 JB	83	};
	84
	85	/* Always use this macro, this allows later putting the
	86	* message into a separate section or such for things
	87	* like translation or listing all possible messages.
	88	* Currently string formatting is not supported (due
	89	* to the lack of an output buffer.)
	90	*/
4d463c4d	91	#define NL_SET_ERR_MSG(extack, msg) do { \
6311b7ce	92	static const char __msg[] = msg; \
4d463c4d DB	93	struct netlink_ext_ack *__extack = (extack); \
4d463c4d DB	94	\
7e3ce05e MRL	95	do_trace_netlink_extack(__msg); \
7e3ce05e MRL	96	\
4d463c4d DB	97	if (__extack) \
4d463c4d DB	98	__extack->_msg = __msg; \
2d4bc933 JB	99	} while (0)
2d4bc933 JB	100
4d463c4d DB	101	#define NL_SET_ERR_MSG_MOD(extack, msg) \
4d463c4d DB	102	NL_SET_ERR_MSG((extack), KBUILD_MODNAME ": " msg)
45d9b378	103
44f3625b JB	104	#define NL_SET_BAD_ATTR_POLICY(extack, attr, pol) do { \
44f3625b JB	105	if ((extack)) { \
c3ab2b4e	106	(extack)->bad_attr = (attr); \
44f3625b JB	107	(extack)->policy = (pol); \
44f3625b JB	108	} \
c3ab2b4e DA	109	} while (0)
c3ab2b4e DA	110
44f3625b JB	111	#define NL_SET_BAD_ATTR(extack, attr) NL_SET_BAD_ATTR_POLICY(extack, attr, NULL)
	112
	113	#define NL_SET_ERR_MSG_ATTR_POL(extack, attr, pol, msg) do { \
	114	static const char __msg[] = msg; \
	115	struct netlink_ext_ack *__extack = (extack); \
	116	\
7e3ce05e MRL	117	do_trace_netlink_extack(__msg); \
7e3ce05e MRL	118	\
44f3625b JB	119	if (__extack) { \
	120	__extack->_msg = __msg; \
	121	__extack->bad_attr = (attr); \
	122	__extack->policy = (pol); \
	123	} \
9ae28727 DA	124	} while (0)
9ae28727 DA	125
44f3625b JB	126	#define NL_SET_ERR_MSG_ATTR(extack, attr, msg) \
	127	NL_SET_ERR_MSG_ATTR_POL(extack, attr, NULL, msg)
	128
801f8746 JB	129	static inline void nl_set_extack_cookie_u64(struct netlink_ext_ack *extack,
	130	u64 cookie)
	131	{
55b474c4 MK	132	if (!extack)
55b474c4 MK	133	return;
c6400e3f AD	134	memcpy(extack->cookie, &cookie, sizeof(cookie));
c6400e3f AD	135	extack->cookie_len = sizeof(cookie);
801f8746 JB	136	}
801f8746 JB	137
aa9d6e0f SH	138	void netlink_kernel_release(struct sock *sk);
	139	int __netlink_change_ngroups(struct sock *sk, unsigned int groups);
	140	int netlink_change_ngroups(struct sock *sk, unsigned int groups);
	141	void __netlink_clear_multicast_users(struct sock *sk, unsigned int group);
	142	void netlink_ack(struct sk_buff in_skb, struct nlmsghdr nlh, int err,
	143	const struct netlink_ext_ack *extack);
	144	int netlink_has_listeners(struct sock *sk, unsigned int group);
59c28058	145	bool netlink_strict_get_check(struct sk_buff *skb);
aa9d6e0f SH	146
	147	int netlink_unicast(struct sock ssk, struct sk_buff skb, __u32 portid, int nonblock);
	148	int netlink_broadcast(struct sock ssk, struct sk_buff skb, __u32 portid,
	149	__u32 group, gfp_t allocation);
aa9d6e0f SH	150	int netlink_set_err(struct sock *ssk, __u32 portid, __u32 group, int code);
	151	int netlink_register_notifier(struct notifier_block *nb);
	152	int netlink_unregister_notifier(struct notifier_block *nb);
1da177e4 LT	153
	154	/* finegrained unicast helpers: */
	155	struct sock netlink_getsockbyfilp(struct file filp);
9457afee	156	int netlink_attachskb(struct sock sk, struct sk_buff skb,
c3d8d1e3	157	long timeo, struct sock ssk);
1da177e4	158	void netlink_detachskb(struct sock sk, struct sk_buff skb);
7ee015e0	159	int netlink_sendskb(struct sock sk, struct sk_buff skb);
1da177e4	160
3a36515f PN	161	static inline struct sk_buff *
	162	netlink_skb_clone(struct sk_buff *skb, gfp_t gfp_mask)
	163	{
	164	struct sk_buff *nskb;
	165
	166	nskb = skb_clone(skb, gfp_mask);
	167	if (!nskb)
	168	return NULL;
	169
	170	/* This is a large skb, set destructor callback to release head */
	171	if (is_vmalloc_addr(skb->head))
	172	nskb->destructor = skb->destructor;
	173
	174	return nskb;
	175	}
	176
1da177e4 LT	177	/*
1da177e4 LT	178	* skb should fit one page. This choice is good for headerless malloc.
fc910a27 DM	179	* But we should limit to 8K so that userspace does not have to
	180	* use enormous buffer sizes on recvmsg() calls just to avoid
	181	* MSG_TRUNC when PAGE_SIZE is very large.
1da177e4	182	*/
fc910a27 DM	183	#if PAGE_SIZE < 8192UL
	184	#define NLMSG_GOODSIZE SKB_WITH_OVERHEAD(PAGE_SIZE)
	185	#else
	186	#define NLMSG_GOODSIZE SKB_WITH_OVERHEAD(8192UL)
	187	#endif
	188
339bf98f	189	#define NLMSG_DEFAULT_SIZE (NLMSG_GOODSIZE - NLMSG_HDRLEN)
1da177e4 LT	190
1da177e4 LT	191
d94d9fee	192	struct netlink_callback {
3a6c2b41 PM	193	struct sk_buff *skb;
	194	const struct nlmsghdr *nlh;
	195	int (dump)(struct sk_buff skb,
	196	struct netlink_callback *cb);
	197	int (done)(struct netlink_callback cb);
7175c883	198	void *data;
6dc878a8 G	199	/* the module that dump function belong to */
6dc878a8 G	200	struct module *module;
4a19edb6	201	struct netlink_ext_ack *extack;
c7ac8679	202	u16 family;
22e6c58b	203	u16 answer_flags;
085c20ca	204	u32 min_dump_alloc;
670dc283	205	unsigned int prev_seq, seq;
085c20ca	206	bool strict_check;
362b87f5 JD	207	union {
	208	u8 ctx[48];
	209
	210	/* args is deprecated. Cast a struct over ctx instead
	211	* for proper type safety.
	212	*/
	213	long args[6];
	214	};
1da177e4 LT	215	};
1da177e4 LT	216
d94d9fee	217	struct netlink_notify {
b4b51029	218	struct net *net;
0392d099	219	u32 portid;
1da177e4 LT	220	int protocol;
	221	};
	222
a46621a3	223	struct nlmsghdr *
15e47304	224	__nlmsg_put(struct sk_buff *skb, u32 portid, u32 seq, int type, int len, int flags);
1da177e4	225
80d326fa	226	struct netlink_dump_control {
fc9e50f5	227	int (start)(struct netlink_callback );
80d326fa	228	int (dump)(struct sk_buff skb, struct netlink_callback *);
6dc878a8	229	int (done)(struct netlink_callback );
7175c883	230	void *data;
6dc878a8	231	struct module *module;
ebfe3c51	232	u32 min_dump_alloc;
80d326fa PNA	233	};
80d326fa PNA	234
aa9d6e0f	235	int __netlink_dump_start(struct sock ssk, struct sk_buff skb,
6dc878a8 G	236	const struct nlmsghdr *nlh,
	237	struct netlink_dump_control *control);
	238	static inline int netlink_dump_start(struct sock ssk, struct sk_buff skb,
	239	const struct nlmsghdr *nlh,
	240	struct netlink_dump_control *control)
	241	{
	242	if (!control->module)
	243	control->module = THIS_MODULE;
	244
	245	return __netlink_dump_start(ssk, skb, nlh, control);
	246	}
1da177e4	247
bcbde0d4 DB	248	struct netlink_tap {
	249	struct net_device *dev;
	250	struct module *module;
	251	struct list_head list;
	252	};
	253
aa9d6e0f SH	254	int netlink_add_tap(struct netlink_tap *nt);
aa9d6e0f SH	255	int netlink_remove_tap(struct netlink_tap *nt);
bcbde0d4	256
aa4cf945 EB	257	bool __netlink_ns_capable(const struct netlink_skb_parms *nsp,
	258	struct user_namespace *ns, int cap);
	259	bool netlink_ns_capable(const struct sk_buff *skb,
	260	struct user_namespace *ns, int cap);
	261	bool netlink_capable(const struct sk_buff *skb, int cap);
	262	bool netlink_net_capable(const struct sk_buff *skb, int cap);
	263
1da177e4	264	#endif /* __LINUX_NETLINK_H */