include/linux/netfilter/nfnetlink.h

   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  * the READ_ONCE(), because 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 */