/*
   * linux/include/linux/sunrpc/svcauth.h
   *
   * RPC server-side authentication stuff.
   *
   * Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de>
   */
  
  #ifndef _LINUX_SUNRPC_SVCAUTH_H_
  #define _LINUX_SUNRPC_SVCAUTH_H_
  
  #ifdef __KERNEL__
  
  #include <linux/string.h>
  #include <linux/sunrpc/msg_prot.h>
  #include <linux/sunrpc/cache.h>
  #include <linux/sunrpc/gss_api.h>
  #include <linux/hash.h>
  #include <linux/cred.h>
  
  struct svc_cred {
  	kuid_t			cr_uid;
  	kgid_t			cr_gid;
  	struct group_info	*cr_group_info;
  	u32			cr_flavor; /* pseudoflavor */
  	char			*cr_principal; /* for gss */
  	struct gss_api_mech	*cr_gss_mech;
  };
  
  static inline void init_svc_cred(struct svc_cred *cred)
  {
  	cred->cr_group_info = NULL;
  	cred->cr_principal = NULL;
  	cred->cr_gss_mech = NULL;
  }
  
  static inline void free_svc_cred(struct svc_cred *cred)
  {
  	if (cred->cr_group_info)
  		put_group_info(cred->cr_group_info);
  	kfree(cred->cr_principal);
  	gss_mech_put(cred->cr_gss_mech);
  	init_svc_cred(cred);
  }
  
  struct svc_rqst;		/* forward decl */
  struct in6_addr;
  
  /* Authentication is done in the context of a domain.
   *
   * Currently, the nfs server uses the auth_domain to stand
   * for the "client" listed in /etc/exports.
   *
   * More generally, a domain might represent a group of clients using
   * a common mechanism for authentication and having a common mapping
   * between local identity (uid) and network identity.  All clients
   * in a domain have similar general access rights.  Each domain can
   * contain multiple principals which will have different specific right
   * based on normal Discretionary Access Control.
   *
   * A domain is created by an authentication flavour module based on name
   * only.  Userspace then fills in detail on demand.
   *
   * In the case of auth_unix and auth_null, the auth_domain is also
   * associated with entries in another cache representing the mapping
   * of ip addresses to the given client.
   */
  struct auth_domain {
  	struct kref		ref;
  	struct hlist_node	hash;
  	char			*name;
  	struct auth_ops		*flavour;
  };
  
  /*
   * Each authentication flavour registers an auth_ops
   * structure.
   * name is simply the name.
   * flavour gives the auth flavour. It determines where the flavour is registered
   * accept() is given a request and should verify it.
   *   It should inspect the authenticator and verifier, and possibly the data.
   *    If there is a problem with the authentication *authp should be set.
   *    The return value of accept() can indicate:
   *      OK - authorised. client and credential are set in rqstp.
   *           reqbuf points to arguments
   *           resbuf points to good place for results.  verfier
   *             is (probably) already in place.  Certainly space is
   *	       reserved for it.
   *      DROP - simply drop the request. It may have been deferred
   *      GARBAGE - rpc garbage_args error
   *      SYSERR - rpc system_err error
   *      DENIED - authp holds reason for denial.
   *      COMPLETE - the reply is encoded already and ready to be sent; no
   *		further processing is necessary.  (This is used for processing
   *		null procedure calls which are used to set up encryption
   *		contexts.)
   *
   *   accept is passed the proc number so that it can accept NULL rpc requests
   *   even if it cannot authenticate the client (as is sometimes appropriate).
   *
   * release() is given a request after the procedure has been run.
   *  It should sign/encrypt the results if needed
   * It should return:
   *    OK - the resbuf is ready to be sent
   *    DROP - the reply should be quitely dropped
   *    DENIED - authp holds a reason for MSG_DENIED
   *    SYSERR - rpc system_err
   *
   * domain_release()
   *   This call releases a domain.
   * set_client()
   *   Givens a pending request (struct svc_rqst), finds and assigns
   *   an appropriate 'auth_domain' as the client.
   */
  struct auth_ops {
  	char *	name;
  	struct module *owner;
  	int	flavour;
  	int	(*accept)(struct svc_rqst *rq, __be32 *authp);
  	int	(*release)(struct svc_rqst *rq);
  	void	(*domain_release)(struct auth_domain *);
  	int	(*set_client)(struct svc_rqst *rq);
  };
  
  #define	SVC_GARBAGE	1
  #define	SVC_SYSERR	2
  #define	SVC_VALID	3
  #define	SVC_NEGATIVE	4
  #define	SVC_OK		5
  #define	SVC_DROP	6
  #define	SVC_CLOSE	7	/* Like SVC_DROP, but request is definitely
  				 * lost so if there is a tcp connection, it
  				 * should be closed
  				 */
  #define	SVC_DENIED	8
  #define	SVC_PENDING	9
  #define	SVC_COMPLETE	10
  
  struct svc_xprt;
  
  extern int	svc_authenticate(struct svc_rqst *rqstp, __be32 *authp);
  extern int	svc_authorise(struct svc_rqst *rqstp);
  extern int	svc_set_client(struct svc_rqst *rqstp);
  extern int	svc_auth_register(rpc_authflavor_t flavor, struct auth_ops *aops);
  extern void	svc_auth_unregister(rpc_authflavor_t flavor);
  
  extern struct auth_domain *unix_domain_find(char *name);
  extern void auth_domain_put(struct auth_domain *item);
  extern int auth_unix_add_addr(struct net *net, struct in6_addr *addr, struct auth_domain *dom);
  extern struct auth_domain *auth_domain_lookup(char *name, struct auth_domain *new);
  extern struct auth_domain *auth_domain_find(char *name);
  extern struct auth_domain *auth_unix_lookup(struct net *net, struct in6_addr *addr);
  extern int auth_unix_forget_old(struct auth_domain *dom);
  extern void svcauth_unix_purge(struct net *net);
  extern void svcauth_unix_info_release(struct svc_xprt *xpt);
  extern int svcauth_unix_set_client(struct svc_rqst *rqstp);
  
  extern int unix_gid_cache_create(struct net *net);
  extern void unix_gid_cache_destroy(struct net *net);
  
  static inline unsigned long hash_str(char *name, int bits)
  {
  	unsigned long hash = 0;
  	unsigned long l = 0;
  	int len = 0;
  	unsigned char c;
  	do {
  		if (unlikely(!(c = *name++))) {
  			c = (char)len; len = -1;
  		}
  		l = (l << 8) | c;
  		len++;
  		if ((len & (BITS_PER_LONG/8-1))==0)
  			hash = hash_long(hash^l, BITS_PER_LONG);
  	} while (len);
  	return hash >> (BITS_PER_LONG - bits);
  }
  
  static inline unsigned long hash_mem(char *buf, int length, int bits)
  {
  	unsigned long hash = 0;
  	unsigned long l = 0;
  	int len = 0;
  	unsigned char c;
  	do {
  		if (len == length) {
  			c = (char)len; len = -1;
  		} else
  			c = *buf++;
  		l = (l << 8) | c;
  		len++;
  		if ((len & (BITS_PER_LONG/8-1))==0)
  			hash = hash_long(hash^l, BITS_PER_LONG);
  	} while (len);
  	return hash >> (BITS_PER_LONG - bits);
  }
  
  #endif /* __KERNEL__ */
  
  #endif /* _LINUX_SUNRPC_SVCAUTH_H_ */