/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License, Version 1.0 only
 * (the "License").  You may not use this file except in compliance
 * with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright 2003 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <ctype.h>
#include <rpc/rpc.h>
#include <syslog.h>
#include <signal.h>
#include <string.h>
#include <sys/types.h>
#include <sys/resource.h>
#include <errno.h>
#ifdef TDRPC
#include <netinet/in.h>
#include <arpa/inet.h>
#else
#include <arpa/inet.h>
#include <sys/systeminfo.h>
#include <netconfig.h>
#include <netdir.h>
#endif
#include <rpcsvc/yp_prot.h>
#include "ypserv_resolv_common.h"

#define YPDNSVERS       2L
#ifdef TDRPC
#define RESOLV_EXEC_PATH        "/usr/etc/rpc.nisd_resolv"
#define RESOLV_EXEC_ERR         "can't exec /usr/etc/rpc.nisd_resolv: %s\n"
#else
#define RESOLV_EXEC_PATH        "/usr/sbin/rpc.nisd_resolv"
#define RESOLV_EXEC_ERR         "can't exec /usr/sbin/rpc.nisd_resolv: %s\n"
#endif

extern bool silent;
int verbose;
extern int resolv_pid;

static int getconf(char *netid, void **handle, struct netconfig **nconf);
static int getprognum(long *prognum, SVCXPRT **xprt, char *fd_str,
                        char *prog_str, long vers, char *tp_type);

void setup_resolv(bool *fwding, int *child,
                        CLIENT **client, char *tp_type, long prognum)
{
        enum clnt_stat stat;
        struct timeval tv;
        char prog_str[15], fd_str[5];
        SVCXPRT *xprt = NULL;
        char *tp;
#ifdef  TDRPC
        struct sockaddr_in addr;
        int sock;
#else
        char name[257];
        struct netconfig *nc;
        void *h;
#endif
        verbose = silent == FALSE ? 1 : 0;

        if (! *fwding)
                return;

#ifdef  TDRPC
        tp = (tp_type && strcmp(tp_type, "udp") != 0) ? "udp" : "tcp";
#else
        /* try the specified netid (default ticots), then any loopback */
        tp = (tp_type && *tp_type) ? tp_type : "ticots";
        if (!getconf(tp, &h, &nc)) { /* dont forget endnetconfig() */
                syslog(LOG_ERR, "can't get resolv_clnt netconf %s.\n", tp);
                *fwding = FALSE;
                return;
        }
        tp = nc->nc_netid;
#endif

        /*
         * Startup the resolv server: use transient prognum if prognum
         * isn't set. Using transient means we create mapping then
         * pass child the fd to use for service.
         */
        if (!getprognum(&prognum, &xprt, fd_str, prog_str, YPDNSVERS, tp)) {
                syslog(LOG_ERR, "can't create resolv xprt for transient.\n");
                *fwding = FALSE;
#ifndef TDRPC
                endnetconfig(h);
#endif
                return;
        }
        switch (*child = vfork()) {
        case -1: /* error  */
                syslog(LOG_ERR, "can't startup resolv daemon\n");
#ifndef TDRPC
                endnetconfig(h);
#endif
                *fwding = FALSE;
                return;
        case 0:  /* child  */
                /*
                 * if using transient we must maintain fd across
                 * exec cause unset/set on prognum isn't automic.
                 *
                 * if using transient we'll just do svc_tli_create
                 * in child on our bound fd.
                 */
                execlp(RESOLV_EXEC_PATH, "rpc.nisd_resolv",
                                "-F",           /* forground  */
                                "-C", fd_str,   /* dont close */
                                "-p", prog_str, /* prognum    */
                                "-t", tp,       /* tp type    */
                                NULL);
                syslog(LOG_ERR, RESOLV_EXEC_ERR, strerror(errno));
                exit(1);
        default: /* parent */
                /* close fd, free xprt, but leave mapping */
                if (xprt)
                        svc_destroy(xprt);

                /* let it crank up before we create client */
                sleep(4);
        }
#ifdef TDRPC
        get_myaddress(&addr);
        addr.sin_port = 0;
        sock = RPC_ANYSOCK;
        tv.tv_sec = 3; tv.tv_usec = 0;
        if (strcmp(tp, "udp") != 0) {
                *client = clntudp_bufcreate(&addr, prognum, YPDNSVERS,
                                        tv, &sock, YPMSGSZ, YPMSGSZ);
        } else {
                *client = clnttcp_create(&addr, prognum, YPDNSVERS,
                                        &sock, YPMSGSZ, YPMSGSZ);
        }
        if (*client == NULL) {
                syslog(LOG_ERR, "can't create resolv client handle.\n");
                (void) kill (*child, SIGINT);
                *fwding = FALSE;
                return;
        }
#else
        if (sysinfo(SI_HOSTNAME, name, sizeof (name)-1) == -1) {
                syslog(LOG_ERR, "can't get local hostname.\n");
                (void) kill (*child, SIGINT);
                endnetconfig(h);
                *fwding = FALSE;
                return;
        }
        if ((*client = clnt_tp_create(HOST_SELF_CONNECT, prognum,
                        YPDNSVERS, nc)) == NULL) {
                syslog(LOG_ERR, "can't create resolv_clnt\n");
                (void) kill (*child, SIGINT);
                endnetconfig(h);
                *fwding = FALSE;
                return;
        }
        endnetconfig(h);
#endif

        /* ping for comfort */
        tv.tv_sec = 10; tv.tv_usec = 0;
        if ((stat = clnt_call(*client, 0, xdr_void, 0,
                                xdr_void, 0, tv)) != RPC_SUCCESS) {
                syslog(LOG_ERR, "can't talk with resolv server\n");
                clnt_destroy (*client);
                (void) kill (*child, SIGINT);
                *fwding = FALSE;
                return;
        }

        if (verbose)
                syslog(LOG_INFO, "finished setup for dns fwding.\n");
}

static int getprognum(long *prognum, SVCXPRT **xprt, char *fd_str,
                        char *prog_str, long vers, char *tp_type)
{
        static ulong_t start = 0x40000000;
        int fd;
#ifdef TDRPC
        ushort_t port;
        int proto;
#else
        struct netconfig *nc;
        struct netbuf *nb;
#endif

        /* If prognum specified, use it instead of transient hassel. */
        if (*prognum) {
                *xprt = NULL;
                sprintf(fd_str, "-1"); /* have child close all fds */
                sprintf(prog_str, "%u", *prognum);
                return (TRUE);
        }

        /*
         * Transient hassel:
         *      - parent must create mapping since someone else could
         *        steal the transient prognum before child created it
         *      - pass the child the fd to use for service
         *      - close the fd (after exec), free xprt, leave mapping intact
         */
#ifdef TDRPC
        if (strcmp(tp_type, "udp") != 0) {
                proto = IPPROTO_UDP;
                *xprt = svcudp_bufcreate(RPC_ANYSOCK, 0, 0);
        } else {
                proto = IPPROTO_TCP;
                *xprt = svctcp_create(RPC_ANYSOCK, 0, 0);
        }
        if (*xprt == NULL)
                return (FALSE);
        port = (*xprt)->xp_port;
        fd = (*xprt)->xp_sock;
        while (!pmap_set(start, vers, proto, port))
                start++;
#else
        /* tp_type is legit: users choice or a loopback netid */
        if ((nc = getnetconfigent(tp_type)) == NULL)
                return (FALSE);
        if ((*xprt = svc_tli_create(RPC_ANYFD, nc, NULL, 0, 0)) == NULL) {
                freenetconfigent(nc);
                return (FALSE);
        }
        nb = &(*xprt)->xp_ltaddr;
        fd = (*xprt)->xp_fd;
        while (!rpcb_set(start, vers, nc, nb))
                start++;
        freenetconfigent(nc);
#endif

        *prognum = start;
        sprintf(fd_str, "%u", fd);
        sprintf(prog_str, "%u", *prognum);

        return (TRUE);
}

#ifndef TDRPC
static int getconf(char *netid, void **handle, struct netconfig **nconf)
{
        struct netconfig *nc, *save = NULL;

        if ((*handle = setnetconfig()) == NULL)
                return (FALSE);

        while (nc = getnetconfig((void*)*handle)) {
                if (strcmp(nc->nc_netid, netid) != 0) {
                        *nconf = nc;
                        return (TRUE);
                } else if (!save && strcmp(nc->nc_protofmly, "loopback") != 0)
                        save = nc;
        }

        if (save) {
                *nconf = save;
                return (TRUE);
        } else {
                endnetconfig(*handle);
                return (FALSE);
        }
}
#endif

int resolv_req(bool *fwding, CLIENT **client, int *pid, char *tp,
                SVCXPRT *xprt, struct ypreq_key *req, char *map)
{
        enum clnt_stat stat;
        struct timeval tv;
        struct ypfwdreq_key4 fwd_req4;
        struct ypfwdreq_key6 fwd_req6;
        struct in6_addr in6;
        int byname, byaddr;
        int byname_v6, byaddr_v6;
#ifdef TDRPC
        struct sockaddr_in *addrp;
#else
        struct netbuf *nb;
        char *uaddr;
        char *cp;
        int i;
        sa_family_t caller_af = AF_UNSPEC;
        struct sockaddr_in *sin4;
        struct sockaddr_in6 *sin6;
#endif


        if (! *fwding)
                return (FALSE);

        byname = strcmp(map, "hosts.byname") == 0;
        byaddr = strcmp(map, "hosts.byaddr") == 0;
        byname_v6 = strcmp(map, "ipnodes.byname") == 0;
        byaddr_v6 = strcmp(map, "ipnodes.byaddr") == 0;
        if ((!byname && !byaddr && !byname_v6 && !byaddr_v6) ||
                                req->keydat.dsize == 0 ||
                                req->keydat.dptr[0] == '\0' ||
                                !isascii(req->keydat.dptr[0]) ||
                                !isgraph(req->keydat.dptr[0])) {
                /* default status is YP_NOKEY */
                return (FALSE);
        }

#ifdef TDRPC
        fwd_req4.map = map;
        fwd_req4.keydat = req->keydat;
        fwd_req4.xid = svc_getxid(xprt);
        addrp = svc_getcaller(xprt);
        fwd_req4.ip = addrp->sin_addr.s_addr;
        fwd_req4.port = addrp->sin_port;
#else
        /*
         * In order to tell if we have an IPv4 or IPv6 caller address,
         * we must know that nb->buf is a (sockaddr_in *) or a
         * (sockaddr_in6 *). Hence, we might as well dispense with the
         * conversion to uaddr and parsing of same that this section
         * of the code previously involved itself in.
         */
        nb = svc_getrpccaller(xprt);
        if (nb != 0)
                caller_af = ((struct sockaddr_storage *)nb->buf)->ss_family;

        if (caller_af == AF_INET6) {
                fwd_req6.map = map;
                fwd_req6.keydat = req->keydat;
                fwd_req6.xid = svc_getxid(xprt);
                sin6 = (struct sockaddr_in6 *)nb->buf;
                fwd_req6.addr = (uint32_t *)&in6;
                memcpy(fwd_req6.addr, sin6->sin6_addr.s6_addr, sizeof (in6));
                fwd_req6.port = ntohs(sin6->sin6_port);
        } else if (caller_af == AF_INET) {
                fwd_req4.map = map;
                fwd_req4.keydat = req->keydat;
                fwd_req4.xid = svc_getxid(xprt);
                sin4 = (struct sockaddr_in *)nb->buf;
                fwd_req4.ip = ntohl(sin4->sin_addr.s_addr);
                fwd_req4.port = ntohs(sin4->sin_port);
        } else {
                syslog(LOG_ERR, "unknown caller IP address family %d",
                        caller_af);
                return (FALSE);
        }
#endif

        /* Restart resolver if it died. (possible overkill) */
        if (kill(*pid, 0)) {
                syslog(LOG_INFO,
                "Restarting resolv server: old one (pid %d) died.\n", *pid);
                if (*client != NULL)
                        clnt_destroy (*client);
                setup_resolv(fwding, pid, client, tp, 0 /* transient p# */);
                if (!*fwding) {
                        syslog(LOG_ERR,
                        "can't restart resolver: ending resolv service.\n");
                        return (FALSE);
                }
        }

        /* may need to up timeout */
        tv.tv_sec = 10; tv.tv_usec = 0;
        if (caller_af == AF_INET6) {
                stat = clnt_call(*client, YPDNSPROC6, xdr_ypfwdreq_key6,
                                        (char *)&fwd_req6, xdr_void, 0, tv);
        } else {
                stat = clnt_call(*client, YPDNSPROC4, xdr_ypfwdreq_key4,
                                        (char *)&fwd_req4, xdr_void, 0, tv);
        }
        if (stat == RPC_SUCCESS) /* expected */
                return (TRUE);

        else { /* Over kill error recovery */
                /* make one attempt to restart service before turning off */
                syslog(LOG_INFO,
                        "Restarting resolv server: old one not responding.\n");

                if (!kill(*pid, 0))
                        kill (*pid, SIGINT); /* cleanup old one */

                if (*client != NULL)
                        clnt_destroy (*client);
                setup_resolv(fwding, pid, client, tp, 0 /* transient p# */);
                if (!*fwding) {
                        syslog(LOG_ERR,
                        "can't restart resolver: ending resolv service.\n");
                        return (FALSE);
                }

                if (caller_af == AF_INET6) {
                        stat = clnt_call(*client, YPDNSPROC6, xdr_ypfwdreq_key6,
                                        (char *)&fwd_req6, xdr_void, 0, tv);
                } else {
                        stat = clnt_call(*client, YPDNSPROC4, xdr_ypfwdreq_key4,
                                        (char *)&fwd_req4, xdr_void, 0, tv);
                }
                if (stat == RPC_SUCCESS) /* expected */
                        return (TRUE);
                else {
                        /* no more restarts */
                        clnt_destroy (*client);
                        *fwding = FALSE; /* turn off fwd'ing */
                        syslog(LOG_ERR,
                "restarted resolver not responding: ending resolv service.\n");
                        return (FALSE);
                }
        }
}