1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _NFNETLINK_H
3 #define _NFNETLINK_H
4
5 #include <linux/netlink.h>
6 #include <linux/capability.h>
7 #include <net/netlink.h>
8 #include <uapi/linux/netfilter/nfnetlink.h>
9
10 struct nfnl_callback {
11 int (*call)(struct net *net, struct sock *nl, struct sk_buff *skb,
12 const struct nlmsghdr *nlh,
13 const struct nlattr * const cda[],
14 struct netlink_ext_ack *extack);
15 int (*call_rcu)(struct net *net, struct sock *nl, struct sk_buff *skb,
16 const struct nlmsghdr *nlh,
17 const struct nlattr * const cda[],
18 struct netlink_ext_ack *extack);
19 int (*call_batch)(struct net *net, struct sock *nl, struct sk_buff *skb,
20 const struct nlmsghdr *nlh,
21 const struct nlattr * const cda[],
22 struct netlink_ext_ack *extack);
23 const struct nla_policy *policy; /* netlink attribute policy */
24 const u_int16_t attr_count; /* number of nlattr's */
25 };
26
27 struct nfnetlink_subsystem {
28 const char *name;
29 __u8 subsys_id; /* nfnetlink subsystem ID */
30 __u8 cb_count; /* number of callbacks */
31 const struct nfnl_callback *cb; /* callback for individual types */
32 struct module *owner;
33 int (*commit)(struct net *net, struct sk_buff *skb);
34 int (*abort)(struct net *net, struct sk_buff *skb);
35 void (*cleanup)(struct net *net);
36 bool (*valid_genid)(struct net *net, u32 genid);
37 };
38
39 int nfnetlink_subsys_register(const struct nfnetlink_subsystem *n);
40 int nfnetlink_subsys_unregister(const struct nfnetlink_subsystem *n);
41
42 int nfnetlink_has_listeners(struct net *net, unsigned int group);
43 int nfnetlink_send(struct sk_buff *skb, struct net *net, u32 portid,
44 unsigned int group, int echo, gfp_t flags);
45 int nfnetlink_set_err(struct net *net, u32 portid, u32 group, int error);
46 int nfnetlink_unicast(struct sk_buff *skb, struct net *net, u32 portid,
47 int flags);
48
nfnl_msg_type(u8 subsys,u8 msg_type)49 static inline u16 nfnl_msg_type(u8 subsys, u8 msg_type)
50 {
51 return subsys << 8 | msg_type;
52 }
53
54 void nfnl_lock(__u8 subsys_id);
55 void nfnl_unlock(__u8 subsys_id);
56 #ifdef CONFIG_PROVE_LOCKING
57 bool lockdep_nfnl_is_held(__u8 subsys_id);
58 #else
lockdep_nfnl_is_held(__u8 subsys_id)59 static inline bool lockdep_nfnl_is_held(__u8 subsys_id)
60 {
61 return true;
62 }
63 #endif /* CONFIG_PROVE_LOCKING */
64
65 /*
66 * nfnl_dereference - fetch RCU pointer when updates are prevented by subsys mutex
67 *
68 * @p: The pointer to read, prior to dereferencing
69 * @ss: The nfnetlink subsystem ID
70 *
71 * Return the value of the specified RCU-protected pointer, but omit
72 * the READ_ONCE(), because caller holds the NFNL subsystem mutex.
73 */
74 #define nfnl_dereference(p, ss) \
75 rcu_dereference_protected(p, lockdep_nfnl_is_held(ss))
76
77 #define MODULE_ALIAS_NFNL_SUBSYS(subsys) \
78 MODULE_ALIAS("nfnetlink-subsys-" __stringify(subsys))
79
80 #endif /* _NFNETLINK_H */
81
