include/linux/netfilter/nfnetlink.h

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