/*
 * network.c -- Provide common network functions for NFS mount/umount
 *
 * Copyright (C) 2007 Oracle.  All rights reserved.
 * Copyright (C) 2007 Chuck Lever <chuck.lever@oracle.com>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public
 * License along with this program; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 021110-1307, USA.
 *
 */

#include <ctype.h>
#include <unistd.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <errno.h>
#include <netdb.h>
#include <time.h>
#include <rpc/rpc.h>
#include <rpc/pmap_prot.h>
#include <rpc/pmap_clnt.h>
#include <sys/socket.h>

#include "conn.h"
#include "xcommon.h"
#include "mount.h"
#include "nls.h"
#include "nfsumount.h"
#include "nfs_mount.h"
#include "mount_constants.h"
#include "network.h"

#ifdef HAVE_RPCSVC_NFS_PROT_H
#include <rpcsvc/nfs_prot.h>
#else
#include <linux/nfs.h>
#define nfsstat nfs_stat
#endif

#ifndef NFS_PORT
#define NFS_PORT 2049
#endif

extern int nfs_mount_data_version;
extern char *progname;
extern int verbose;

static const unsigned int probe_udp_only[] = {
	IPPROTO_UDP,
	0,
};

static const unsigned int probe_udp_first[] = {
	IPPROTO_UDP,
	IPPROTO_TCP,
	0,
};

static const unsigned int probe_tcp_first[] = {
	IPPROTO_TCP,
	IPPROTO_UDP,
	0,
};

static const unsigned long probe_nfs2_only[] = {
	2,
	0,
};

static const unsigned long probe_nfs3_first[] = {
	3,
	2,
	0,
};

static const unsigned long probe_mnt1_first[] = {
	1,
	2,
	0,
};

static const unsigned long probe_mnt3_first[] = {
	3,
	1,
	2,
	0,
};

int nfs_gethostbyname(const char *hostname, struct sockaddr_in *saddr)
{
	struct hostent *hp;

	saddr->sin_family = AF_INET;
	if (!inet_aton(hostname, &saddr->sin_addr)) {
		if ((hp = gethostbyname(hostname)) == NULL) {
			nfs_error(_("mount: can't get address for %s\n"),
				hostname);
			return 0;
		} else {
			if (hp->h_length > sizeof(*saddr)) {
				nfs_error(_("mount: got bad hp->h_length\n"));
				hp->h_length = sizeof(*saddr);
			}
			memcpy(&saddr->sin_addr, hp->h_addr, hp->h_length);
		}
	}
	return 1;
}

/*
 * getport() is very similar to pmap_getport() with
 * the exception this version uses a non-reserve ports
 * instead of reserve ports since reserve ports
 * are not needed for pmap requests.
 */
unsigned short getport(struct sockaddr_in *saddr, unsigned long prog,
			unsigned long vers, unsigned int prot)
{
	unsigned short port = 0;
	int socket;
	CLIENT *clnt = NULL;
	struct pmap parms;
	enum clnt_stat stat;

	saddr->sin_port = htons (PMAPPORT);
	socket = get_socket(saddr, prot, FALSE, FALSE);

	switch (prot) {
	case IPPROTO_UDP:
		clnt = clntudp_bufcreate(saddr,
					 PMAPPROG, PMAPVERS, TIMEOUT, &socket,
					 UDPMSGSIZE, UDPMSGSIZE);
		break;
	case IPPROTO_TCP:
		clnt = clnttcp_create(saddr,
			PMAPPROG, PMAPVERS, &socket, 50, 500);
		break;
	}
	if (clnt != NULL) {
		parms.pm_prog = prog;
		parms.pm_vers = vers;
		parms.pm_prot = prot;
		parms.pm_port = 0;    /* not needed or used */

		stat = clnt_call(clnt, PMAPPROC_GETPORT, (xdrproc_t)xdr_pmap,
			(caddr_t)&parms, (xdrproc_t)xdr_u_short, (caddr_t)&port, TIMEOUT);
		if (stat) {
			clnt_geterr(clnt, &rpc_createerr.cf_error);
			rpc_createerr.cf_stat = stat;
		}
		clnt_destroy(clnt);
		if (stat != RPC_SUCCESS)
			port = 0;
		else if (port == 0)
			rpc_createerr.cf_stat = RPC_PROGNOTREGISTERED;
	}
	if (socket != 1)
		close(socket);

	return port;
}

/*
 * Use the portmapper to discover whether or not the service we want is
 * available. The lists 'versions' and 'protos' define ordered sequences
 * of service versions and udp/tcp protocols to probe for.
 */
static int probe_port(clnt_addr_t *server, const unsigned long *versions,
			const unsigned int *protos)
{
	struct sockaddr_in *saddr = &server->saddr;
	struct pmap *pmap = &server->pmap;
	const unsigned long prog = pmap->pm_prog, *p_vers;
	const unsigned int prot = (u_int)pmap->pm_prot, *p_prot;
	const u_short port = (u_short) pmap->pm_port;
	unsigned long vers = pmap->pm_vers;
	unsigned short p_port;

	p_prot = prot ? &prot : protos;
	p_vers = vers ? &vers : versions;
	rpc_createerr.cf_stat = 0;
	for (;;) {
		saddr->sin_port = htons(PMAPPORT);
		p_port = getport(saddr, prog, *p_vers, *p_prot);
		if (p_port) {
			if (!port || port == p_port) {
				saddr->sin_port = htons(p_port);
				if (verbose) {
					printf(_("%s: trying %s prog %ld vers "
						"%ld prot %s port %d\n"),
						progname,
						inet_ntoa(saddr->sin_addr),
						prog, *p_vers,
						*p_prot == IPPROTO_UDP ?
							"udp" : "tcp",
						p_port);
                                }
				if (clnt_ping(saddr, prog, *p_vers, *p_prot, NULL))
					goto out_ok;
				if (rpc_createerr.cf_stat == RPC_TIMEDOUT)
					goto out_bad;
			}
		}
		if (rpc_createerr.cf_stat != RPC_PROGNOTREGISTERED)
			goto out_bad;

		if (!prot) {
			if (*++p_prot)
				continue;
			p_prot = protos;
		}
		if (vers == pmap->pm_vers) {
			p_vers = versions;
			vers = 0;
		}
		if (vers || !*++p_vers)
			break;
	}

out_bad:
	return 0;

out_ok:
	if (!vers)
		pmap->pm_vers = *p_vers;
	if (!prot)
		pmap->pm_prot = *p_prot;
	if (!port)
		pmap->pm_port = p_port;
	rpc_createerr.cf_stat = 0;
	return 1;
}

int probe_nfsport(clnt_addr_t *nfs_server)
{
	struct pmap *pmap = &nfs_server->pmap;

	if (pmap->pm_vers && pmap->pm_prot && pmap->pm_port)
		return 1;

	if (nfs_mount_data_version >= 4)
		return probe_port(nfs_server, probe_nfs3_first, probe_tcp_first);
	else
		return probe_port(nfs_server, probe_nfs2_only, probe_udp_only);
}

int probe_mntport(clnt_addr_t *mnt_server)
{
	struct pmap *pmap = &mnt_server->pmap;

	if (pmap->pm_vers && pmap->pm_prot && pmap->pm_port)
		return 1;

	if (nfs_mount_data_version >= 4)
		return probe_port(mnt_server, probe_mnt3_first, probe_udp_first);
	else
		return probe_port(mnt_server, probe_mnt1_first, probe_udp_only);
}

int probe_bothports(clnt_addr_t *mnt_server, clnt_addr_t *nfs_server)
{
	struct pmap *nfs_pmap = &nfs_server->pmap;
	struct pmap *mnt_pmap = &mnt_server->pmap;
	struct pmap save_nfs, save_mnt;
	int res;
	const unsigned long *probe_vers;

	if (mnt_pmap->pm_vers && !nfs_pmap->pm_vers)
		nfs_pmap->pm_vers = mntvers_to_nfs(mnt_pmap->pm_vers);
	else if (nfs_pmap->pm_vers && !mnt_pmap->pm_vers)
		mnt_pmap->pm_vers = nfsvers_to_mnt(nfs_pmap->pm_vers);
	if (nfs_pmap->pm_vers)
		goto version_fixed;

	memcpy(&save_nfs, nfs_pmap, sizeof(save_nfs));
	memcpy(&save_mnt, mnt_pmap, sizeof(save_mnt));
	probe_vers = (nfs_mount_data_version >= 4) ?
			probe_mnt3_first : probe_mnt1_first;

	for (; *probe_vers; probe_vers++) {
		nfs_pmap->pm_vers = mntvers_to_nfs(*probe_vers);
		if ((res = probe_nfsport(nfs_server) != 0)) {
			mnt_pmap->pm_vers = nfsvers_to_mnt(nfs_pmap->pm_vers);
			if ((res = probe_mntport(mnt_server)) != 0)
				return 1;
			memcpy(mnt_pmap, &save_mnt, sizeof(*mnt_pmap));
		}
		switch (rpc_createerr.cf_stat) {
		case RPC_PROGVERSMISMATCH:
		case RPC_PROGNOTREGISTERED:
			break;
		default:
			goto out_bad;
		}
		memcpy(nfs_pmap, &save_nfs, sizeof(*nfs_pmap));
	}

out_bad:
	return 0;

version_fixed:
	if (!probe_nfsport(nfs_server))
		goto out_bad;
	return probe_mntport(mnt_server);
}

static int probe_statd(void)
{
	struct sockaddr_in addr;
	unsigned short port;

	memset(&addr, 0, sizeof(addr));
	addr.sin_family = AF_INET;
	addr.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
	port = getport(&addr, 100024, 1, IPPROTO_UDP);

	if (port == 0)
		return 0;
	addr.sin_port = htons(port);

	if (clnt_ping(&addr, 100024, 1, IPPROTO_UDP, NULL) <= 0)
		return 0;

	return 1;
}

/*
 * Attempt to start rpc.statd
 */
int start_statd(void)
{
#ifdef START_STATD
	struct stat stb;
#endif

	if (probe_statd())
		return 1;

#ifdef START_STATD
	if (stat(START_STATD, &stb) == 0) {
		if (S_ISREG(stb.st_mode) && (stb.st_mode & S_IXUSR)) {
			system(START_STATD);
			if (probe_statd())
				return 1;
		}
	}
#endif

	return 0;
}