Add support for backchannels to the kernel RPC. Backchannels

are used by NFSv4.1 for callbacks. A backchannel is a connection
established by the client, but used for RPCs done by the server
on the client (callbacks). As a result, this patch mixes some
client side calls in the server side and vice versa. Some
definitions in the .c files were extracted out into a file called
krpc.h, so that they could be included in multiple .c files.
This code has been in projects/nfsv4.1-client for some time.
Although no one has given it a formal review, I believe kib@
has taken a look at it.

1 files changed, 111 insertions, 0 deletions

diff --git a/sys/rpc/krpc.h b/sys/rpc/krpc.h
new file mode 100644
index 0000000..05bf1d4
--- /dev/null
+++ b/sys/rpc/krpc.h
@@ -0,0 +1,111 @@
+/*-
+ * Sun RPC is a product of Sun Microsystems, Inc. and is provided for
+ * unrestricted use provided that this legend is included on all tape
+ * media and as a part of the software program in whole or part.  Users
+ * may copy or modify Sun RPC without charge, but are not authorized
+ * to license or distribute it to anyone else except as part of a product or
+ * program developed by the user.
+ * 
+ * SUN RPC IS PROVIDED AS IS WITH NO WARRANTIES OF ANY KIND INCLUDING THE
+ * WARRANTIES OF DESIGN, MERCHANTIBILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE, OR ARISING FROM A COURSE OF DEALING, USAGE OR TRADE PRACTICE.
+ * 
+ * Sun RPC is provided with no support and without any obligation on the
+ * part of Sun Microsystems, Inc. to assist in its use, correction,
+ * modification or enhancement.
+ * 
+ * SUN MICROSYSTEMS, INC. SHALL HAVE NO LIABILITY WITH RESPECT TO THE
+ * INFRINGEMENT OF COPYRIGHTS, TRADE SECRETS OR ANY PATENTS BY SUN RPC
+ * OR ANY PART THEREOF.
+ * 
+ * In no event will Sun Microsystems, Inc. be liable for any lost revenue
+ * or profits or other special, indirect and consequential damages, even if
+ * Sun has been advised of the possibility of such damages.
+ * 
+ * Sun Microsystems, Inc.
+ * 2550 Garcia Avenue
+ * Mountain View, California  94043
+ *
+ * $FreeBSD$
+ */
+
+#ifndef _RPC_KRPC_H_
+#define	_RPC_KRPC_H_
+
+#ifdef _KERNEL
+/*
+ * Definitions now shared between client and server RPC for backchannels.
+ */
+#define MCALL_MSG_SIZE 24
+
+/*
+ * A pending RPC request which awaits a reply. Requests which have
+ * received their reply will have cr_xid set to zero and cr_mrep to
+ * the mbuf chain of the reply.
+ */
+struct ct_request {
+	TAILQ_ENTRY(ct_request) cr_link;
+	uint32_t		cr_xid;		/* XID of request */
+	struct mbuf		*cr_mrep;	/* reply received by upcall */
+	int			cr_error;	/* any error from upcall */
+	char			cr_verf[MAX_AUTH_BYTES]; /* reply verf */
+};
+
+TAILQ_HEAD(ct_request_list, ct_request);
+
+struct rc_data {
+	struct mtx		rc_lock;
+	struct sockaddr_storage	rc_addr; /* server address */
+	struct netconfig*	rc_nconf; /* network type */
+	rpcprog_t		rc_prog;  /* program number */
+	rpcvers_t		rc_vers;  /* version number */
+	size_t			rc_sendsz;
+	size_t			rc_recvsz;
+	struct timeval		rc_timeout;
+	struct timeval		rc_retry;
+	int			rc_retries;
+	int			rc_privport;
+	char			*rc_waitchan;
+	int			rc_intr;
+	int			rc_connecting;
+	int			rc_closed;
+	struct ucred		*rc_ucred;
+	CLIENT*			rc_client; /* underlying RPC client */
+	struct rpc_err		rc_err;
+	void			*rc_backchannel;
+};
+
+struct ct_data {
+	struct mtx	ct_lock;
+	int		ct_threads;	/* number of threads in clnt_vc_call */
+	bool_t		ct_closing;	/* TRUE if we are closing */
+	bool_t		ct_closed;	/* TRUE if we are closed */
+	struct socket	*ct_socket;	/* connection socket */
+	bool_t		ct_closeit;	/* close it on destroy */
+	struct timeval	ct_wait;	/* wait interval in milliseconds */
+	struct sockaddr_storage	ct_addr; /* remote addr */
+	struct rpc_err	ct_error;
+	uint32_t	ct_xid;
+	char		ct_mcallc[MCALL_MSG_SIZE]; /* marshalled callmsg */
+	size_t		ct_mpos;	/* pos after marshal */
+	const char	*ct_waitchan;
+	int		ct_waitflag;
+	struct mbuf	*ct_record;	/* current reply record */
+	size_t		ct_record_resid; /* how much left of reply to read */
+	bool_t		ct_record_eor;	 /* true if reading last fragment */
+	struct ct_request_list ct_pending;
+	int		ct_upcallrefs;	/* Ref cnt of upcalls in prog. */
+	SVCXPRT		*ct_backchannelxprt; /* xprt for backchannel */
+};
+
+struct cf_conn {  /* kept in xprt->xp_p1 for actual connection */
+	enum xprt_stat strm_stat;
+	struct mbuf *mpending;	/* unparsed data read from the socket */
+	struct mbuf *mreq;	/* current record being built from mpending */
+	uint32_t resid;		/* number of bytes needed for fragment */
+	bool_t eor;		/* reading last fragment of current record */
+};
+
+#endif	/* _KERNEL */
+
+#endif	/* _RPC_KRPC_H_ */