text: /*
   * linux/include/linux/sunrpc/svc.h
   *
   * RPC server declarations.
   *
   * Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de>
   */
  
  
  #ifndef SUNRPC_SVC_H
  #define SUNRPC_SVC_H
  
  #include <linux/in.h>
  #include <linux/in6.h>
  #include <linux/sunrpc/types.h>
  #include <linux/sunrpc/xdr.h>
  #include <linux/sunrpc/auth.h>
  #include <linux/sunrpc/svcauth.h>
  #include <linux/wait.h>
  #include <linux/mm.h>
  
  /*
   * This is the RPC server thread function prototype
   */
  typedef int		(*svc_thread_fn)(void *);
  
  /* statistics for svc_pool structures */
  struct svc_pool_stats {
  	unsigned long	packets;
  	unsigned long	sockets_queued;
  	unsigned long	threads_woken;
  	unsigned long	threads_timedout;
  };
  
  /*
   *
   * RPC service thread pool.
   *
   * Pool of threads and temporary sockets.  Generally there is only
   * a single one of these per RPC service, but on NUMA machines those
   * services that can benefit from it (i.e. nfs but not lockd) will
   * have one pool per NUMA node.  This optimisation reduces cross-
   * node traffic on multi-node NUMA NFS servers.
   */
  struct svc_pool {
  	unsigned int		sp_id;	    	/* pool id; also node id on NUMA */
  	spinlock_t		sp_lock;	/* protects all fields */
  	struct list_head	sp_threads;	/* idle server threads */
  	struct list_head	sp_sockets;	/* pending sockets */
  	unsigned int		sp_nrthreads;	/* # of threads in pool */
  	struct list_head	sp_all_threads;	/* all server threads */
  	struct svc_pool_stats	sp_stats;	/* statistics on pool operation */
  } ____cacheline_aligned_in_smp;
  
  /*
   * RPC service.
   *
   * An RPC service is a ``daemon,'' possibly multithreaded, which
   * receives and processes incoming RPC messages.
   * It has one or more transport sockets associated with it, and maintains
   * a list of idle threads waiting for input.
   *
   * We currently do not support more than one RPC program per daemon.
   */
  struct svc_serv {
  	struct svc_program *	sv_program;	/* RPC program */
  	struct svc_stat *	sv_stats;	/* RPC statistics */
  	spinlock_t		sv_lock;
  	unsigned int		sv_nrthreads;	/* # of server threads */
  	unsigned int		sv_maxconn;	/* max connections allowed or
  						 * '0' causing max to be based
  						 * on number of threads. */
  
  	unsigned int		sv_max_payload;	/* datagram payload size */
  	unsigned int		sv_max_mesg;	/* max_payload + 1 page for overheads */
  	unsigned int		sv_xdrsize;	/* XDR buffer size */
  	struct list_head	sv_permsocks;	/* all permanent sockets */
  	struct list_head	sv_tempsocks;	/* all temporary sockets */
  	int			sv_tmpcnt;	/* count of temporary sockets */
  	struct timer_list	sv_temptimer;	/* timer for aging temporary sockets */
  
  	char *			sv_name;	/* service name */
  
  	unsigned int		sv_nrpools;	/* number of thread pools */
  	struct svc_pool *	sv_pools;	/* array of thread pools */
  
  	void			(*sv_shutdown)(struct svc_serv *serv);
  						/* Callback to use when last thread
  						 * exits.
  						 */
  
  	struct module *		sv_module;	/* optional module to count when
  						 * adding threads */
  	svc_thread_fn		sv_function;	/* main function for threads */
  #if defined(CONFIG_SUNRPC_BACKCHANNEL)
  	struct list_head	sv_cb_list;	/* queue for callback requests
  						 * that arrive over the same
  						 * connection */
  	spinlock_t		sv_cb_lock;	/* protects the svc_cb_list */
  	wait_queue_head_t	sv_cb_waitq;	/* sleep here if there are no
  						 * entries in the svc_cb_list */
  	struct svc_xprt		*sv_bc_xprt;	/* callback on fore channel */
  #endif /* CONFIG_SUNRPC_BACKCHANNEL */
  };
  
  /*
   * We use sv_nrthreads as a reference count.  svc_destroy() drops
   * this refcount, so we need to bump it up around operations that
   * change the number of threads.  Horrible, but there it is.
   * Should be called with the BKL held.
   */
  static inline void svc_get(struct svc_serv *serv)
  {
  	serv->sv_nrthreads++;
  }
  
  /*
   * Maximum payload size supported by a kernel RPC server.
   * This is use to determine the max number of pages nfsd is
   * willing to return in a single READ operation.
   *
   * These happen to all be powers of 2, which is not strictly
   * necessary but helps enforce the real limitation, which is
   * that they should be multiples of PAGE_CACHE_SIZE.
   *
   * For UDP transports, a block plus NFS,RPC, and UDP headers
   * has to fit into the IP datagram limit of 64K.  The largest
   * feasible number for all known page sizes is probably 48K,
   * but we choose 32K here.  This is the same as the historical
   * Linux limit; someone who cares more about NFS/UDP performance
   * can test a larger number.
   *
   * For TCP transports we have more freedom.  A size of 1MB is
   * chosen to match the client limit.  Other OSes are known to
   * have larger limits, but those numbers are probably beyond
   * the point of diminishing returns.
   */
  #define RPCSVC_MAXPAYLOAD	(1*1024*1024u)
  #define RPCSVC_MAXPAYLOAD_TCP	RPCSVC_MAXPAYLOAD
  #define RPCSVC_MAXPAYLOAD_UDP	(32*1024u)
  
  extern u32 svc_max_payload(const struct svc_rqst *rqstp);
  
  /*
   * RPC Requsts and replies are stored in one or more pages.
   * We maintain an array of pages for each server thread.
   * Requests are copied into these pages as they arrive.  Remaining
   * pages are available to write the reply into.
   *
   * Pages are sent using ->sendpage so each server thread needs to
   * allocate more to replace those used in sending.  To help keep track
   * of these pages we have a receive list where all pages initialy live,
   * and a send list where pages are moved to when there are to be part
   * of a reply.
   *
   * We use xdr_buf for holding responses as it fits well with NFS
   * read responses (that have a header, and some data pages, and possibly
   * a tail) and means we can share some client side routines.
   *
   * The xdr_buf.head kvec always points to the first page in the rq_*pages
   * list.  The xdr_buf.pages pointer points to the second page on that
   * list.  xdr_buf.tail points to the end of the first page.
   * This assumes that the non-page part of an rpc reply will fit
   * in a page - NFSd ensures this.  lockd also has no trouble.
   *
   * Each request/reply pair can have at most one "payload", plus two pages,
   * one for the request, and one for the reply.
   * We using ->sendfile to return read data, we might need one extra page
   * if the request is not page-aligned.  So add another '1'.
   */
  #define RPCSVC_MAXPAGES		((RPCSVC_MAXPAYLOAD+PAGE_SIZE-1)/PAGE_SIZE \
  				+ 2 + 1)
  
  static inline u32 svc_getnl(struct kvec *iov)
  {
  	__be32 val, *vp;
  	vp = iov->iov_base;
  	val = *vp++;
  	iov->iov_base = (void*)vp;
  	iov->iov_len -= sizeof(__be32);
  	return ntohl(val);
  }
  
  static inline void svc_putnl(struct kvec *iov, u32 val)
  {
  	__be32 *vp = iov->iov_base + iov->iov_len;
  	*vp = htonl(val);
  	iov->iov_len += sizeof(__be32);
  }
  
  static inline __be32 svc_getu32(struct kvec *iov)
  {
  	__be32 val, *vp;
  	vp = iov->iov_base;
  	val = *vp++;
  	iov->iov_base = (void*)vp;
  	iov->iov_len -= sizeof(__be32);
  	return val;
  }
  
  static inline void svc_ungetu32(struct kvec *iov)
  {
  	__be32 *vp = (__be32 *)iov->iov_base;
  	iov->iov_base = (void *)(vp - 1);
  	iov->iov_len += sizeof(*vp);
  }
  
  static inline void svc_putu32(struct kvec *iov, __be32 val)
  {
  	__be32 *vp = iov->iov_base + iov->iov_len;
  	*vp = val;
  	iov->iov_len += sizeof(__be32);
  }
  
  /*
   * The context of a single thread, including the request currently being
   * processed.
   */
  struct svc_rqst {
  	struct list_head	rq_list;	/* idle list */
  	struct list_head	rq_all;		/* all threads list */
  	struct svc_xprt *	rq_xprt;	/* transport ptr */
  
  	struct sockaddr_storage	rq_addr;	/* peer address */
  	size_t			rq_addrlen;
  	struct sockaddr_storage	rq_daddr;	/* dest addr of request
  						 *  - reply from here */
  	size_t			rq_daddrlen;
  
  	struct svc_serv *	rq_server;	/* RPC service definition */
  	struct svc_pool *	rq_pool;	/* thread pool */
  	struct svc_procedure *	rq_procinfo;	/* procedure info */
  	struct auth_ops *	rq_authop;	/* authentication flavour */
  	u32			rq_flavor;	/* pseudoflavor */
  	struct svc_cred		rq_cred;	/* auth info */
  	void *			rq_xprt_ctxt;	/* transport specific context ptr */
  	struct svc_deferred_req*rq_deferred;	/* deferred request we are replaying */
  	int			rq_usedeferral;	/* use deferral */
  
  	size_t			rq_xprt_hlen;	/* xprt header len */
  	struct xdr_buf		rq_arg;
  	struct xdr_buf		rq_res;
  	struct page *		rq_pages[RPCSVC_MAXPAGES];
  	struct page *		*rq_respages;	/* points into rq_pages */
  	int			rq_resused;	/* number of pages used for result */
  
  	struct kvec		rq_vec[RPCSVC_MAXPAGES]; /* generally useful.. */
  
  	__be32			rq_xid;		/* transmission id */
  	u32			rq_prog;	/* program number */
  	u32			rq_vers;	/* program version */
  	u32			rq_proc;	/* procedure number */
  	u32			rq_prot;	/* IP protocol */
  	unsigned short
  				rq_secure  : 1;	/* secure port */
  
  	void *			rq_argp;	/* decoded arguments */
  	void *			rq_resp;	/* xdr'd results */
  	void *			rq_auth_data;	/* flavor-specific data */
  
  	int			rq_reserved;	/* space on socket outq
  						 * reserved for this request
  						 */
  
  	struct cache_req	rq_chandle;	/* handle passed to caches for 
  						 * request delaying 
  						 */
  	bool			rq_dropme;
  	/* Catering to nfsd */
  	struct auth_domain *	rq_client;	/* RPC peer info */
  	struct auth_domain *	rq_gssclient;	/* "gss/"-style peer info */
  	int			rq_cachetype;
  	struct svc_cacherep *	rq_cacherep;	/* cache info */
  	int			rq_splice_ok;   /* turned off in gss privacy
  						 * to prevent encrypting page
  						 * cache pages */
  	wait_queue_head_t	rq_wait;	/* synchronization */
  	struct task_struct	*rq_task;	/* service thread */
  };
  
  /*
   * Rigorous type checking on sockaddr type conversions
   */
  static inline struct sockaddr_in *svc_addr_in(const struct svc_rqst *rqst)
  {
  	return (struct sockaddr_in *) &rqst->rq_addr;
  }
  
  static inline struct sockaddr_in6 *svc_addr_in6(const struct svc_rqst *rqst)
  {
  	return (struct sockaddr_in6 *) &rqst->rq_addr;
  }
  
  static inline struct sockaddr *svc_addr(const struct svc_rqst *rqst)
  {
  	return (struct sockaddr *) &rqst->rq_addr;
  }
  
  static inline struct sockaddr_in *svc_daddr_in(const struct svc_rqst *rqst)
  {
  	return (struct sockaddr_in *) &rqst->rq_daddr;
  }
  
  static inline struct sockaddr_in6 *svc_daddr_in6(const struct svc_rqst *rqst)
  {
  	return (struct sockaddr_in6 *) &rqst->rq_daddr;
  }
  
  static inline struct sockaddr *svc_daddr(const struct svc_rqst *rqst)
  {
  	return (struct sockaddr *) &rqst->rq_daddr;
  }
  
  /*
   * Check buffer bounds after decoding arguments
   */
  static inline int
  xdr_argsize_check(struct svc_rqst *rqstp, __be32 *p)
  {
  	char *cp = (char *)p;
  	struct kvec *vec = &rqstp->rq_arg.head[0];
  	return cp >= (char*)vec->iov_base
  		&& cp <= (char*)vec->iov_base + vec->iov_len;
  }
  
  static inline int
  xdr_ressize_check(struct svc_rqst *rqstp, __be32 *p)
  {
  	struct kvec *vec = &rqstp->rq_res.head[0];
  	char *cp = (char*)p;
  
  	vec->iov_len = cp - (char*)vec->iov_base;
  
  	return vec->iov_len <= PAGE_SIZE;
  }
  
  static inline void svc_free_res_pages(struct svc_rqst *rqstp)
  {
  	while (rqstp->rq_resused) {
  		struct page **pp = (rqstp->rq_respages +
  				    --rqstp->rq_resused);
  		if (*pp) {
  			put_page(*pp);
  			*pp = NULL;
  		}
  	}
  }
  
  struct svc_deferred_req {
  	u32			prot;	/* protocol (UDP or TCP) */
  	struct svc_xprt		*xprt;
  	struct sockaddr_storage	addr;	/* where reply must go */
  	size_t			addrlen;
  	struct sockaddr_storage	daddr;	/* where reply must come from */
  	size_t			daddrlen;
  	struct cache_deferred_req handle;
  	size_t			xprt_hlen;
  	int			argslen;
  	__be32			args[0];
  };
  
  /*
   * List of RPC programs on the same transport endpoint
   */
  struct svc_program {
  	struct svc_program *	pg_next;	/* other programs (same xprt) */
  	u32			pg_prog;	/* program number */
  	unsigned int		pg_lovers;	/* lowest version */
  	unsigned int		pg_hivers;	/* lowest version */
  	unsigned int		pg_nvers;	/* number of versions */
  	struct svc_version **	pg_vers;	/* version array */
  	char *			pg_name;	/* service name */
  	char *			pg_class;	/* class name: services sharing authentication */
  	struct svc_stat *	pg_stats;	/* rpc statistics */
  	int			(*pg_authenticate)(struct svc_rqst *);
  };
  
  /*
   * RPC program version
   */
  struct svc_version {
  	u32			vs_vers;	/* version number */
  	u32			vs_nproc;	/* number of procedures */
  	struct svc_procedure *	vs_proc;	/* per-procedure info */
  	u32			vs_xdrsize;	/* xdrsize needed for this version */
  
  	unsigned int		vs_hidden : 1;	/* Don't register with portmapper.
  						 * Only used for nfsacl so far. */
  
  	/* Override dispatch function (e.g. when caching replies).
  	 * A return value of 0 means drop the request. 
  	 * vs_dispatch == NULL means use default dispatcher.
  	 */
  	int			(*vs_dispatch)(struct svc_rqst *, __be32 *);
  };
  
  /*
   * RPC procedure info
   */
  typedef __be32	(*svc_procfunc)(struct svc_rqst *, void *argp, void *resp);
  struct svc_procedure {
  	svc_procfunc		pc_func;	/* process the request */
  	kxdrproc_t		pc_decode;	/* XDR decode args */
  	kxdrproc_t		pc_encode;	/* XDR encode result */
  	kxdrproc_t		pc_release;	/* XDR free result */
  	unsigned int		pc_argsize;	/* argument struct size */
  	unsigned int		pc_ressize;	/* result struct size */
  	unsigned int		pc_count;	/* call count */
  	unsigned int		pc_cachetype;	/* cache info (NFS) */
  	unsigned int		pc_xdrressize;	/* maximum size of XDR reply */
  };
  
  /*
   * Function prototypes.
   */
  void svc_rpcb_cleanup(struct svc_serv *serv);
  struct svc_serv *svc_create(struct svc_program *, unsigned int,
  			    void (*shutdown)(struct svc_serv *));
  struct svc_rqst *svc_prepare_thread(struct svc_serv *serv,
  					struct svc_pool *pool, int node);
  void		   svc_exit_thread(struct svc_rqst *);
  struct svc_serv *  svc_create_pooled(struct svc_program *, unsigned int,
  			void (*shutdown)(struct svc_serv *),
  			svc_thread_fn, struct module *);
  int		   svc_set_num_threads(struct svc_serv *, struct svc_pool *, int);
  int		   svc_pool_stats_open(struct svc_serv *serv, struct file *file);
  void		   svc_destroy(struct svc_serv *);
  int		   svc_process(struct svc_rqst *);
  int		   bc_svc_process(struct svc_serv *, struct rpc_rqst *,
  			struct svc_rqst *);
  int		   svc_register(const struct svc_serv *, const int,
  				const unsigned short, const unsigned short);
  
  void		   svc_wake_up(struct svc_serv *);
  void		   svc_reserve(struct svc_rqst *rqstp, int space);
  struct svc_pool *  svc_pool_for_cpu(struct svc_serv *serv, int cpu);
  char *		   svc_print_addr(struct svc_rqst *, char *, size_t);
  
  #define	RPC_MAX_ADDRBUFLEN	(63U)
  
  /*
   * When we want to reduce the size of the reserved space in the response
   * buffer, we need to take into account the size of any checksum data that
   * may be at the end of the packet. This is difficult to determine exactly
   * for all cases without actually generating the checksum, so we just use a
   * static value.
   */
  static inline void svc_reserve_auth(struct svc_rqst *rqstp, int space)
  {
  	int added_space = 0;
  
  	if (rqstp->rq_authop->flavour)
  		added_space = RPC_MAX_AUTH_SIZE;
  	svc_reserve(rqstp, space + added_space);
  }
  
  #endif /* SUNRPC_SVC_H */
  