LXR linux/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
  10struct 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
  27struct 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
  37int nfnetlink_subsys_register(const struct nfnetlink_subsystem *n);
  38int nfnetlink_subsys_unregister(const struct nfnetlink_subsystem *n);
  39
  40int nfnetlink_has_listeners(struct net *net, unsigned int group);
  41int nfnetlink_send(struct sk_buff *skb, struct net *net, u32 portid,
  42                   unsigned int group, int echo, gfp_t flags);
  43int nfnetlink_set_err(struct net *net, u32 portid, u32 group, int error);
  44int nfnetlink_unicast(struct sk_buff *skb, struct net *net, u32 portid,
  45                      int flags);
  46
  47static inline u16 nfnl_msg_type(u8 subsys, u8 msg_type)
  48{
  49        return subsys << 8 | msg_type;
  50}
  51
  52void nfnl_lock(__u8 subsys_id);
  53void nfnl_unlock(__u8 subsys_id);
  54#ifdef CONFIG_PROVE_LOCKING
  55bool lockdep_nfnl_is_held(__u8 subsys_id);
  56#else
  57static 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 ACCESS_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