netlink.h

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#ifndef __LINUX_NETLINK_H
#define __LINUX_NETLINK_H

#define NETLINK_ROUTE           0       /* Routing/device hook                          */
#define NETLINK_SKIP            1       /* Reserved for ENskip                          */
#define NETLINK_USERSOCK        2       /* Reserved for user mode socket protocols      */
#define NETLINK_FIREWALL        3       /* Firewalling hook                             */
#define NETLINK_ARPD            8
#define NETLINK_ROUTE6          11      /* af_inet6 route comm channel */
#define NETLINK_IP6_FW          13
#define NETLINK_TAPBASE         16      /* 16 to 31 are ethertap */

#define MAX_LINKS 32            

struct sockaddr_nl
{
        sa_family_t     nl_family;      /* AF_NETLINK   */
        unsigned short  nl_pad;         /* zero         */
        __u32           nl_pid;         /* process pid  */
        __u32           nl_groups;      /* multicast groups mask */
};

struct nlmsghdr
{
        __u32           nlmsg_len;      /* Length of message including header */
        __u16           nlmsg_type;     /* Message content */
        __u16           nlmsg_flags;    /* Additional flags */
        __u32           nlmsg_seq;      /* Sequence number */
        __u32           nlmsg_pid;      /* Sending process PID */
};

/* Flags values */

#define NLM_F_REQUEST           1       /* It is request message.       */
#define NLM_F_MULTI             2       /* Multipart message, terminated by NLMSG_DONE */
#define NLM_F_ACK               4       /* Reply with ack, with zero or error code */
#define NLM_F_ECHO              8       /* Echo this request            */

/* Modifiers to GET request */
#define NLM_F_ROOT      0x100   /* specify tree root    */
#define NLM_F_MATCH     0x200   /* return all matching  */
#define NLM_F_ATOMIC    0x400   /* atomic GET           */
#define NLM_F_DUMP      (NLM_F_ROOT|NLM_F_MATCH)

/* Modifiers to NEW request */
#define NLM_F_REPLACE   0x100   /* Override existing            */
#define NLM_F_EXCL      0x200   /* Do not touch, if it exists   */
#define NLM_F_CREATE    0x400   /* Create, if it does not exist */
#define NLM_F_APPEND    0x800   /* Add to end of list           */

/*
   4.4BSD ADD           NLM_F_CREATE|NLM_F_EXCL
   4.4BSD CHANGE        NLM_F_REPLACE

   True CHANGE          NLM_F_CREATE|NLM_F_REPLACE
   Append               NLM_F_CREATE
   Check                NLM_F_EXCL
 */

#define NLMSG_ALIGNTO   4
#define NLMSG_ALIGN(len) ( ((len)+NLMSG_ALIGNTO-1) & ~(NLMSG_ALIGNTO-1) )
#define NLMSG_LENGTH(len) ((len)+NLMSG_ALIGN(sizeof(struct nlmsghdr)))
#define NLMSG_SPACE(len) NLMSG_ALIGN(NLMSG_LENGTH(len))
#define NLMSG_DATA(nlh)  ((void*)(((char*)nlh) + NLMSG_LENGTH(0)))
#define NLMSG_NEXT(nlh,len)      ((len) -= NLMSG_ALIGN((nlh)->nlmsg_len), \
                                  (struct nlmsghdr*)(((char*)(nlh)) + NLMSG_ALIGN((nlh)->nlmsg_len)))
#define NLMSG_OK(nlh,len) ((len) > 0 && (nlh)->nlmsg_len >= sizeof(struct nlmsghdr) && \
                           (nlh)->nlmsg_len <= (len))
#define NLMSG_PAYLOAD(nlh,len) ((nlh)->nlmsg_len - NLMSG_SPACE((len)))

#define NLMSG_NOOP              0x1     /* Nothing.             */
#define NLMSG_ERROR             0x2     /* Error                */
#define NLMSG_DONE              0x3     /* End of a dump        */
#define NLMSG_OVERRUN           0x4     /* Data lost            */

struct nlmsgerr
{
        int             error;
        struct nlmsghdr msg;
};

#define NET_MAJOR 36            /* Major 36 is reserved for networking                                          */

#ifdef __KERNEL__

struct netlink_skb_parms
{
        struct ucred            creds;          /* Skb credentials      */
        __u32                   pid;
        __u32                   groups;
        __u32                   dst_pid;
        __u32                   dst_groups;
        kernel_cap_t            eff_cap;
};

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


extern int netlink_attach(int unit, int (*function)(int,struct sk_buff *skb));
extern void netlink_detach(int unit);
extern int netlink_post(int unit, struct sk_buff *skb);
extern int init_netlink(void);
extern struct sock *netlink_kernel_create(int unit, void (*input)(struct sock *sk, int len));
extern void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err);
extern int netlink_unicast(struct sock *ssk, struct sk_buff *skb, __u32 pid, int nonblock);
extern void netlink_broadcast(struct sock *ssk, struct sk_buff *skb, __u32 pid,
                              __u32 group, int allocation);
extern void netlink_set_err(struct sock *ssk, __u32 pid, __u32 group, int code);

/*
 *      skb should fit one page. This choice is good for headerless malloc.
 *
 *      FIXME: What is the best size for SLAB???? --ANK
 */
#define NLMSG_GOODSIZE (PAGE_SIZE - ((sizeof(struct sk_buff)+0xF)&~0xF))


struct netlink_callback
{
        struct sk_buff  *skb;
        struct nlmsghdr *nlh;
        int             (*dump)(struct sk_buff * skb, struct netlink_callback *cb);
        int             (*done)(struct netlink_callback *cb);
        int             family;
        long            args[4];
};

extern __inline__ struct nlmsghdr *
__nlmsg_put(struct sk_buff *skb, u32 pid, u32 seq, int type, int len)
{
        struct nlmsghdr *nlh;
        int size = NLMSG_LENGTH(len);

        nlh = (struct nlmsghdr*)skb_put(skb, NLMSG_ALIGN(size));
        nlh->nlmsg_type = type;
        nlh->nlmsg_len = size;
        nlh->nlmsg_flags = 0;
        nlh->nlmsg_pid = pid;
        nlh->nlmsg_seq = seq;
        return nlh;
}

#define NLMSG_PUT(skb, pid, seq, type, len) \
({ if (skb_tailroom(skb) < (int)NLMSG_SPACE(len)) goto nlmsg_failure; \
   __nlmsg_put(skb, pid, seq, type, len); })

extern int netlink_dump_start(struct sock *ssk, struct sk_buff *skb,
                              struct nlmsghdr *nlh,
                              int (*dump)(struct sk_buff *skb, struct netlink_callback*),
                              int (*done)(struct netlink_callback*));


extern void netlink_proto_init(struct net_proto *pro);

#endif /* __KERNEL__ */

#endif  /* __LINUX_NETLINK_H */

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