path: root/net/sunrpc/rpcb_clnt.c

/*
 * In-kernel rpcbind client supporting versions 2, 3, and 4 of the rpcbind
 * protocol
 *
 * Based on RFC 1833: "Binding Protocols for ONC RPC Version 2" and
 * RFC 3530: "Network File System (NFS) version 4 Protocol"
 *
 * Original: Gilles Quillard, Bull Open Source, 2005 <gilles.quillard@bull.net>
 * Updated: Chuck Lever, Oracle Corporation, 2007 <chuck.lever@oracle.com>
 *
 * Descended from net/sunrpc/pmap_clnt.c,
 *  Copyright (C) 1996, Olaf Kirch <okir@monad.swb.de>
 */

#include <linux/module.h>

#include <linux/types.h>
#include <linux/socket.h>
#include <linux/in.h>
#include <linux/in6.h>
#include <linux/kernel.h>
#include <linux/errno.h>

#include <linux/sunrpc/clnt.h>
#include <linux/sunrpc/sched.h>
#include <linux/sunrpc/xprtsock.h>

#ifdef RPC_DEBUG
# define RPCDBG_FACILITY	RPCDBG_BIND
#endif

#define RPCBIND_PROGRAM		(100000u)
#define RPCBIND_PORT		(111u)

#define RPCBVERS_2		(2u)
#define RPCBVERS_3		(3u)
#define RPCBVERS_4		(4u)

enum {
	RPCBPROC_NULL,
	RPCBPROC_SET,
	RPCBPROC_UNSET,
	RPCBPROC_GETPORT,
	RPCBPROC_GETADDR = 3,		/* alias for GETPORT */
	RPCBPROC_DUMP,
	RPCBPROC_CALLIT,
	RPCBPROC_BCAST = 5,		/* alias for CALLIT */
	RPCBPROC_GETTIME,
	RPCBPROC_UADDR2TADDR,
	RPCBPROC_TADDR2UADDR,
	RPCBPROC_GETVERSADDR,
	RPCBPROC_INDIRECT,
	RPCBPROC_GETADDRLIST,
	RPCBPROC_GETSTAT,
};

#define RPCB_HIGHPROC_2		RPCBPROC_CALLIT
#define RPCB_HIGHPROC_3		RPCBPROC_TADDR2UADDR
#define RPCB_HIGHPROC_4		RPCBPROC_GETSTAT

/*
 * r_owner
 *
 * The "owner" is allowed to unset a service in the rpcbind database.
 * We always use the following (arbitrary) fixed string.
 */
#define RPCB_OWNER_STRING	"rpcb"
#define RPCB_MAXOWNERLEN	sizeof(RPCB_OWNER_STRING)

static void			rpcb_getport_done(struct rpc_task *, void *);
static struct rpc_program	rpcb_program;

struct rpcbind_args {
	struct rpc_xprt *	r_xprt;

	u32			r_prog;
	u32			r_vers;
	u32			r_prot;
	unsigned short		r_port;
	const char *		r_netid;
	const char *		r_addr;
	const char *		r_owner;
};

static struct rpc_procinfo rpcb_procedures2[];
static struct rpc_procinfo rpcb_procedures3[];

struct rpcb_info {
	u32			rpc_vers;
	struct rpc_procinfo *	rpc_proc;
};

static struct rpcb_info rpcb_next_version[];
static struct rpcb_info rpcb_next_version6[];

static void rpcb_map_release(void *data)
{
	struct rpcbind_args *map = data;

	xprt_put(map->r_xprt);
	kfree(map);
}

static const struct rpc_call_ops rpcb_getport_ops = {
	.rpc_call_done		= rpcb_getport_done,
	.rpc_release		= rpcb_map_release,
};

static void rpcb_wake_rpcbind_waiters(struct rpc_xprt *xprt, int status)
{
	xprt_clear_binding(xprt);
	rpc_wake_up_status(&xprt->binding, status);
}

static struct rpc_clnt *rpcb_create(char *hostname, struct sockaddr *srvaddr,
				    size_t salen, int proto, u32 version,
				    int privileged)
{
	struct rpc_create_args args = {
		.protocol	= proto,
		.address	= srvaddr,
		.addrsize	= salen,
		.servername	= hostname,
		.program	= &rpcb_program,
		.version	= version,
		.authflavor	= RPC_AUTH_UNIX,
		.flags		= RPC_CLNT_CREATE_NOPING,
	};

	switch (srvaddr->sa_family) {
	case AF_INET:
		((struct sockaddr_in *)srvaddr)->sin_port = htons(RPCBIND_PORT);
		break;
	case AF_INET6:
		((struct sockaddr_in6 *)srvaddr)->sin6_port = htons(RPCBIND_PORT);
		break;
	default:
		return NULL;
	}

	if (!privileged)
		args.flags |= RPC_CLNT_CREATE_NONPRIVPORT;
	return rpc_create(&args);
}

/**
 * rpcb_register - set or unset a port registration with the local rpcbind svc
 * @prog: RPC program number to bind
 * @vers: RPC version number to bind
 * @prot: transport protocol to use to make this request
 * @port: port value to register
 * @okay: result code
 *
 * port == 0 means unregister, port != 0 means register.
 *
 * This routine supports only rpcbind version 2.
 */
int rpcb_register(u32 prog, u32 vers, int prot, unsigned short port, int *okay)
{
	struct sockaddr_in sin = {
		.sin_family		= AF_INET,
		.sin_addr.s_addr	= htonl(INADDR_LOOPBACK),
	};
	struct rpcbind_args map = {
		.r_prog		= prog,
		.r_vers		= vers,
		.r_prot		= prot,
		.r_port		= port,
	};
	struct rpc_message msg = {
		.rpc_proc	= &rpcb_procedures2[port ?
					RPCBPROC_SET : RPCBPROC_UNSET],
		.rpc_argp	= &map,
		.rpc_resp	= okay,
	};
	struct rpc_clnt *rpcb_clnt;
	int error = 0;

	dprintk("RPC:       %sregistering (%u, %u, %d, %u) with local "
			"rpcbind\n", (port ? "" : "un"),
			prog, vers, prot, port);

	rpcb_clnt = rpcb_create("localhost", (struct sockaddr *) &sin,
				sizeof(sin), XPRT_TRANSPORT_UDP, RPCBVERS_2, 1);
	if (IS_ERR(rpcb_clnt))
		return PTR_ERR(rpcb_clnt);

	error = rpc_call_sync(rpcb_clnt, &msg, 0);

	rpc_shutdown_client(rpcb_clnt);
	if (error < 0)
		printk(KERN_WARNING "RPC: failed to contact local rpcbind "
				"server (errno %d).\n", -error);
	dprintk("RPC:       registration status %d/%d\n", error, *okay);

	return error;
}

/**
 * rpcb_getport_sync - obtain the port for an RPC service on a given host
 * @sin: address of remote peer
 * @prog: RPC program number to bind
 * @vers: RPC version number to bind
 * @prot: transport protocol to use to make this request
 *
 * Return value is the requested advertised port number,
 * or a negative errno value.
 *
 * Called from outside the RPC client in a synchronous task context.
 * Uses default timeout parameters specified by underlying transport.
 *
 * XXX: Needs to support IPv6
 */
int rpcb_getport_sync(struct sockaddr_in *sin, u32 prog, u32 vers, int prot)
{
	struct rpcbind_args map = {
		.r_prog		= prog,
		.r_vers		= vers,
		.r_prot		= prot,
		.r_port		= 0,
	};
	struct rpc_message msg = {
		.rpc_proc	= &rpcb_procedures2[RPCBPROC_GETPORT],
		.rpc_argp	= &map,
		.rpc_resp	= &map.r_port,
	};
	struct rpc_clnt	*rpcb_clnt;
	int status;

	dprintk("RPC:       %s(" NIPQUAD_FMT ", %u, %u, %d)\n",
		__func__, NIPQUAD(sin->sin_addr.s_addr), prog, vers, prot);

	rpcb_clnt = rpcb_create(NULL, (struct sockaddr *)sin,
				sizeof(*sin), prot, RPCBVERS_2, 0);
	if (IS_ERR(rpcb_clnt))
		return PTR_ERR(rpcb_clnt);

	status = rpc_call_sync(rpcb_clnt, &msg, 0);
	rpc_shutdown_client(rpcb_clnt);

	if (status >= 0) {
		if (map.r_port != 0)
			return map.r_port;
		status = -EACCES;
	}
	return status;
}
EXPORT_SYMBOL_GPL(rpcb_getport_sync);

static struct