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root/include/linux/netlink.h

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INCLUDED FROM


DEFINITIONS

This source file includes following definitions.
  1. nlmsg_hdr
  2. __nlmsg_put

#ifndef __LINUX_NETLINK_H
#define __LINUX_NETLINK_H

#include <linux/socket.h> /* for sa_family_t */
#include <linux/types.h>

#define NETLINK_ROUTE           0       /* Routing/device hook                          */
#define NETLINK_UNUSED          1       /* Unused number                                */
#define NETLINK_USERSOCK        2       /* Reserved for user mode socket protocols      */
#define NETLINK_FIREWALL        3       /* Firewalling hook                             */
#define NETLINK_INET_DIAG       4       /* INET socket monitoring                       */
#define NETLINK_NFLOG           5       /* netfilter/iptables ULOG */
#define NETLINK_XFRM            6       /* ipsec */
#define NETLINK_SELINUX         7       /* SELinux event notifications */
#define NETLINK_ISCSI           8       /* Open-iSCSI */
#define NETLINK_AUDIT           9       /* auditing */
#define NETLINK_FIB_LOOKUP      10      
#define NETLINK_CONNECTOR       11
#define NETLINK_NETFILTER       12      /* netfilter subsystem */
#define NETLINK_IP6_FW          13
#define NETLINK_DNRTMSG         14      /* DECnet routing messages */
#define NETLINK_KOBJECT_UEVENT  15      /* Kernel messages to userspace */
#define NETLINK_GENERIC         16
/* leave room for NETLINK_DM (DM Events) */
#define NETLINK_SCSITRANSPORT   18      /* SCSI Transports */
#define NETLINK_ECRYPTFS        19

#define MAX_LINKS 32            

struct net;

struct sockaddr_nl
{
        sa_family_t     nl_family;      /* AF_NETLINK   */
        unsigned short  nl_pad;         /* zero         */
        __u32           nl_pid;         /* port ID      */
        __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 port ID */
};

/* 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_HDRLEN     ((int) NLMSG_ALIGN(sizeof(struct nlmsghdr)))
#define NLMSG_LENGTH(len) ((len)+NLMSG_ALIGN(NLMSG_HDRLEN))
#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) >= (int)sizeof(struct nlmsghdr) && \
                           (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            */

#define NLMSG_MIN_TYPE          0x10    /* < 0x10: reserved control messages */

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

#define NETLINK_ADD_MEMBERSHIP  1
#define NETLINK_DROP_MEMBERSHIP 2
#define NETLINK_PKTINFO         3

struct nl_pktinfo
{
        __u32   group;
};

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

enum {
        NETLINK_UNCONNECTED = 0,
        NETLINK_CONNECTED,
};

/*
 *  <------- NLA_HDRLEN ------> <-- NLA_ALIGN(payload)-->
 * +---------------------+- - -+- - - - - - - - - -+- - -+
 * |        Header       | Pad |     Payload       | Pad |
 * |   (struct nlattr)   | ing |                   | ing |
 * +---------------------+- - -+- - - - - - - - - -+- - -+
 *  <-------------- nlattr->nla_len -------------->
 */

struct nlattr
{
        __u16           nla_len;
        __u16           nla_type;
};

/*
 * nla_type (16 bits)
 * +---+---+-------------------------------+
 * | N | O | Attribute Type                |
 * +---+---+-------------------------------+
 * N := Carries nested attributes
 * O := Payload stored in network byte order
 *
 * Note: The N and O flag are mutually exclusive.
 */
#define NLA_F_NESTED            (1 << 15)
#define NLA_F_NET_BYTEORDER     (1 << 14)
#define NLA_TYPE_MASK           ~(NLA_F_NESTED | NLA_F_NET_BYTEORDER)

#define NLA_ALIGNTO             4
#define NLA_ALIGN(len)          (((len) + NLA_ALIGNTO - 1) & ~(NLA_ALIGNTO - 1))
#define NLA_HDRLEN              ((int) NLA_ALIGN(sizeof(struct nlattr)))

#ifdef __KERNEL__

#include <linux/capability.h>
#include <linux/skbuff.h>

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

struct netlink_skb_parms
{
        struct ucred            creds;          /* Skb credentials      */
        __u32                   pid;
        __u32                   dst_group;
        kernel_cap_t            eff_cap;
        __u32                   loginuid;       /* Login (audit) uid */
        __u32                   sessionid;      /* Session id (audit) */
        __u32                   sid;            /* SELinux security id */
};

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


extern struct sock *netlink_kernel_create(struct net *net,
                                          int unit,unsigned int groups,
                                          void (*input)(struct sk_buff *skb),
                                          struct mutex *cb_mutex,
                                          struct module *module);
extern void netlink_kernel_release(struct sock *sk);
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 int netlink_unicast(struct sock *ssk, struct sk_buff *skb, __u32 pid, int nonblock);
extern int netlink_broadcast(struct sock *ssk, struct sk_buff *skb, __u32 pid,
                             __u32 group, gfp_t allocation);
extern void netlink_set_err(struct sock *ssk, __u32 pid, __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);

/*
 *      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;
        struct nlmsghdr *nlh;
        int             (*dump)(struct sk_buff * skb, struct netlink_callback *cb);
        int             (*done)(struct netlink_callback *cb);
        int             family;
        long            args[6];
};

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

static __inline__ struct nlmsghdr *
__nlmsg_put(struct sk_buff *skb, u32 pid, u32 seq, int type, int len, int flags)
{
        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 = flags;
        nlh->nlmsg_pid = pid;
        nlh->nlmsg_seq = seq;
        memset(NLMSG_DATA(nlh) + len, 0, NLMSG_ALIGN(size) - size);
        return nlh;
}

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

#define NLMSG_PUT(skb, pid, seq, type, len) \
        NLMSG_NEW(skb, pid, seq, type, len, 0)

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*));


#define NL_NONROOT_RECV 0x1
#define NL_NONROOT_SEND 0x2
extern void netlink_set_nonroot(int protocol, unsigned flag);

#endif /* __KERNEL__ */

#endif  /* __LINUX_NETLINK_H */

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