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 int (*commit)(struct net *net, struct sk_buff *skb); 33 int (*abort)(struct net *net, struct sk_buff *skb); 34 bool (*valid_genid)(struct net *net, u32 genid); 35 }; 36 37 int nfnetlink_subsys_register(const struct nfnetlink_subsystem *n); 38 int nfnetlink_subsys_unregister(const struct nfnetlink_subsystem *n); 39 40 int nfnetlink_has_listeners(struct net *net, unsigned int group); 41 int nfnetlink_send(struct sk_buff *skb, struct net *net, u32 portid, 42 unsigned int group, int echo, gfp_t flags); 43 int nfnetlink_set_err(struct net *net, u32 portid, u32 group, int error); 44 int nfnetlink_unicast(struct sk_buff *skb, struct net *net, u32 portid, 45 int flags); 46 47 static inline u16 nfnl_msg_type(u8 subsys, u8 msg_type) 48 { 49 return subsys << 8 | msg_type; 50 } 51 52 void nfnl_lock(__u8 subsys_id); 53 void nfnl_unlock(__u8 subsys_id); 54 #ifdef CONFIG_PROVE_LOCKING 55 bool lockdep_nfnl_is_held(__u8 subsys_id); 56 #else 57 static inline bool lockdep_nfnl_is_held(__u8 subsys_id) 58 { 59 return true; 60 } 61 #endif /* CONFIG_PROVE_LOCKING */ 62 63 /* 64 * nfnl_dereference - fetch RCU pointer when updates are prevented by subsys mutex 65 * 66 * @p: The pointer to read, prior to dereferencing 67 * @ss: The nfnetlink subsystem ID 68 * 69 * Return the value of the specified RCU-protected pointer, but omit 70 * both the smp_read_barrier_depends() and the READ_ONCE(), because 71 * caller holds the NFNL subsystem mutex. 72 */ 73 #define nfnl_dereference(p, ss) \ 74 rcu_dereference_protected(p, lockdep_nfnl_is_held(ss)) 75 76 #define MODULE_ALIAS_NFNL_SUBSYS(subsys) \ 77 MODULE_ALIAS("nfnetlink-subsys-" __stringify(subsys)) 78 79 #endif /* _NFNETLINK_H */ 80