#ifndef __LINUX_NET_SCM_H
  #define __LINUX_NET_SCM_H
  
  #include <linux/limits.h>
  #include <linux/net.h>

  #include <linux/security.h>

  #include <linux/pid.h>
  #include <linux/nsproxy.h>

  
  /* Well, we should have at least one descriptor open
   * to accept passed FDs 8)
   */

  #define SCM_MAX_FD	255

  struct scm_fp_list {

  	struct list_head	list;
  	int			count;
  	struct file		*fp[SCM_MAX_FD];

  };

  struct scm_cookie {

  	struct ucred		creds;		/* Skb credentials	*/
  	struct scm_fp_list	*fp;		/* Passed files		*/

  #ifdef CONFIG_SECURITY_NETWORK

  	u32			secid;		/* Passed security ID 	*/

  #endif

  };
  
  extern void scm_detach_fds(struct msghdr *msg, struct scm_cookie *scm);
  extern void scm_detach_fds_compat(struct msghdr *msg, struct scm_cookie *scm);
  extern int __scm_send(struct socket *sock, struct msghdr *msg, struct scm_cookie *scm);
  extern void __scm_destroy(struct scm_cookie *scm);
  extern struct scm_fp_list * scm_fp_dup(struct scm_fp_list *fpl);

  #ifdef CONFIG_SECURITY_NETWORK
  static __inline__ void unix_get_peersec_dgram(struct socket *sock, struct scm_cookie *scm)
  {
  	security_socket_getpeersec_dgram(sock, NULL, &scm->secid);
  }
  #else
  static __inline__ void unix_get_peersec_dgram(struct socket *sock, struct scm_cookie *scm)
  { }
  #endif /* CONFIG_SECURITY_NETWORK */

  static __inline__ void scm_destroy(struct scm_cookie *scm)
  {
  	if (scm && scm->fp)
  		__scm_destroy(scm);
  }
  
  static __inline__ int scm_send(struct socket *sock, struct msghdr *msg,
  			       struct scm_cookie *scm)
  {

  	struct task_struct *p = current;

  	scm->creds.uid = current_uid();
  	scm->creds.gid = current_gid();

  	scm->creds.pid = task_tgid_vnr(p);

  	scm->fp = NULL;

  	unix_get_peersec_dgram(sock, scm);

  	if (msg->msg_controllen <= 0)
  		return 0;
  	return __scm_send(sock, msg, scm);
  }

  #ifdef CONFIG_SECURITY_NETWORK
  static inline void scm_passec(struct socket *sock, struct msghdr *msg, struct scm_cookie *scm)
  {

  	char *secdata;
  	u32 seclen;
  	int err;
  
  	if (test_bit(SOCK_PASSSEC, &sock->flags)) {
  		err = security_secid_to_secctx(scm->secid, &secdata, &seclen);
  
  		if (!err) {
  			put_cmsg(msg, SOL_SOCKET, SCM_SECURITY, seclen, secdata);
  			security_release_secctx(secdata, seclen);
  		}
  	}

  }
  #else
  static inline void scm_passec(struct socket *sock, struct msghdr *msg, struct scm_cookie *scm)
  { }
  #endif /* CONFIG_SECURITY_NETWORK */

  static __inline__ void scm_recv(struct socket *sock, struct msghdr *msg,
  				struct scm_cookie *scm, int flags)
  {

  	if (!msg->msg_control) {

  		if (test_bit(SOCK_PASSCRED, &sock->flags) || scm->fp)
  			msg->msg_flags |= MSG_CTRUNC;
  		scm_destroy(scm);
  		return;
  	}
  
  	if (test_bit(SOCK_PASSCRED, &sock->flags))
  		put_cmsg(msg, SOL_SOCKET, SCM_CREDENTIALS, sizeof(scm->creds), &scm->creds);

  	scm_passec(sock, msg, scm);

  	if (!scm->fp)
  		return;
  	
  	scm_detach_fds(msg, scm);
  }
  
  
  #endif /* __LINUX_NET_SCM_H */