root/include/linux/netlink.h

INCLUDED FROM

DEFINITIONS

1. nlmsg_hdr
2. netlink_kernel_create
3. netlink_skb_clone
4. netlink_dump_start

#ifndef __LINUX_NETLINK_H
#define __LINUX_NETLINK_H


#include <linux/capability.h>
#include <linux/skbuff.h>
#include <linux/export.h>
#include <net/scm.h>
#include <uapi/linux/netlink.h>

struct net;

static inline struct nlmsghdr *nlmsg_hdr(const struct sk_buff *skb)
{
        return (struct nlmsghdr *)skb->data;
}

enum netlink_skb_flags {
        NETLINK_SKB_MMAPED      = 0x1,  /* Packet data is mmaped */
        NETLINK_SKB_TX          = 0x2,  /* Packet was sent by userspace */
        NETLINK_SKB_DELIVERED   = 0x4,  /* Packet was delivered */
        NETLINK_SKB_DST         = 0x8,  /* Dst set in sendto or sendmsg */
};

struct netlink_skb_parms {
        struct scm_creds        creds;          /* Skb credentials      */
        __u32                   portid;
        __u32                   dst_group;
        __u32                   flags;
        struct sock             *sk;
};

#define NETLINK_CB(skb)         (*(struct netlink_skb_parms*)&((skb)->cb))
#define NETLINK_CREDS(skb)      (&NETLINK_CB((skb)).creds)


extern void netlink_table_grab(void);
extern void netlink_table_ungrab(void);

#define NL_CFG_F_NONROOT_RECV   (1 << 0)
#define NL_CFG_F_NONROOT_SEND   (1 << 1)

/* optional Netlink kernel configuration parameters */
struct netlink_kernel_cfg {
        unsigned int    groups;
        unsigned int    flags;
        void            (*input)(struct sk_buff *skb);
        struct mutex    *cb_mutex;
        int             (*bind)(int group);
        void            (*unbind)(int group);
        bool            (*compare)(struct net *net, struct sock *sk);
};

extern struct sock *__netlink_kernel_create(struct net *net, int unit,
                                            struct module *module,
                                            struct netlink_kernel_cfg *cfg);
static inline struct sock *
netlink_kernel_create(struct net *net, int unit, struct netlink_kernel_cfg *cfg)
{
        return __netlink_kernel_create(net, unit, THIS_MODULE, cfg);
}

extern void netlink_kernel_release(struct sock *sk);
extern int __netlink_change_ngroups(struct sock *sk, unsigned int groups);
extern int netlink_change_ngroups(struct sock *sk, unsigned int groups);
extern void __netlink_clear_multicast_users(struct sock *sk, unsigned int group);
extern void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err);
extern int netlink_has_listeners(struct sock *sk, unsigned int group);
extern struct sk_buff *netlink_alloc_skb(struct sock *ssk, unsigned int size,
                                         u32 dst_portid, gfp_t gfp_mask);
extern int netlink_unicast(struct sock *ssk, struct sk_buff *skb, __u32 portid, int nonblock);
extern int netlink_broadcast(struct sock *ssk, struct sk_buff *skb, __u32 portid,
                             __u32 group, gfp_t allocation);
extern int netlink_broadcast_filtered(struct sock *ssk, struct sk_buff *skb,
        __u32 portid, __u32 group, gfp_t allocation,
        int (*filter)(struct sock *dsk, struct sk_buff *skb, void *data),
        void *filter_data);
extern int netlink_set_err(struct sock *ssk, __u32 portid, __u32 group, int code);
extern int netlink_register_notifier(struct notifier_block *nb);
extern int netlink_unregister_notifier(struct notifier_block *nb);

/* finegrained unicast helpers: */
struct sock *netlink_getsockbyfilp(struct file *filp);
int netlink_attachskb(struct sock *sk, struct sk_buff *skb,
                      long *timeo, struct sock *ssk);
void netlink_detachskb(struct sock *sk, struct sk_buff *skb);
int netlink_sendskb(struct sock *sk, struct sk_buff *skb);

static inline struct sk_buff *
netlink_skb_clone(struct sk_buff *skb, gfp_t gfp_mask)
{
        struct sk_buff *nskb;

        nskb = skb_clone(skb, gfp_mask);
        if (!nskb)
                return NULL;

        /* This is a large skb, set destructor callback to release head */
        if (is_vmalloc_addr(skb->head))
                nskb->destructor = skb->destructor;

        return nskb;
}

/*
 *      skb should fit one page. This choice is good for headerless malloc.
 *      But we should limit to 8K so that userspace does not have to
 *      use enormous buffer sizes on recvmsg() calls just to avoid
 *      MSG_TRUNC when PAGE_SIZE is very large.
 */
#if PAGE_SIZE < 8192UL
#define NLMSG_GOODSIZE  SKB_WITH_OVERHEAD(PAGE_SIZE)
#else
#define NLMSG_GOODSIZE  SKB_WITH_OVERHEAD(8192UL)
#endif

#define NLMSG_DEFAULT_SIZE (NLMSG_GOODSIZE - NLMSG_HDRLEN)


struct netlink_callback {
        struct sk_buff          *skb;
        const struct nlmsghdr   *nlh;
        int                     (*dump)(struct sk_buff * skb,
                                        struct netlink_callback *cb);
        int                     (*done)(struct netlink_callback *cb);
        void                    *data;
        /* the module that dump function belong to */
        struct module           *module;
        u16                     family;
        u16                     min_dump_alloc;
        unsigned int            prev_seq, seq;
        long                    args[6];
};

struct netlink_notify {
        struct net *net;
        int portid;
        int protocol;
};

struct nlmsghdr *
__nlmsg_put(struct sk_buff *skb, u32 portid, u32 seq, int type, int len, int flags);

struct netlink_dump_control {
        int (*dump)(struct sk_buff *skb, struct netlink_callback *);
        int (*done)(struct netlink_callback *);
        void *data;
        struct module *module;
        u16 min_dump_alloc;
};

extern int __netlink_dump_start(struct sock *ssk, struct sk_buff *skb,
                                const struct nlmsghdr *nlh,
                                struct netlink_dump_control *control);
static inline int netlink_dump_start(struct sock *ssk, struct sk_buff *skb,
                                     const struct nlmsghdr *nlh,
                                     struct netlink_dump_control *control)
{
        if (!control->module)
                control->module = THIS_MODULE;

        return __netlink_dump_start(ssk, skb, nlh, control);
}

struct netlink_tap {
        struct net_device *dev;
        struct module *module;
        struct list_head list;
};

extern int netlink_add_tap(struct netlink_tap *nt);
extern int netlink_remove_tap(struct netlink_tap *nt);

bool __netlink_ns_capable(const struct netlink_skb_parms *nsp,
                          struct user_namespace *ns, int cap);
bool netlink_ns_capable(const struct sk_buff *skb,
                        struct user_namespace *ns, int cap);
bool netlink_capable(const struct sk_buff *skb, int cap);
bool netlink_net_capable(const struct sk_buff *skb, int cap);

#endif  /* __LINUX_NETLINK_H */