/*      $NetBSD: rpc.c,v 1.18 1998/01/23 19:27:45 thorpej Exp $ */
/* $DragonFly: src/lib/libstand/rpc.c,v 1.3 2005/12/11 02:27:26 swildner Exp $                                                  */

/*
 * Copyright (c) 1992 Regents of the University of California.
 * All rights reserved.
 *
 * This software was developed by the Computer Systems Engineering group
 * at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and
 * contributed to Berkeley.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * @(#) Header: rpc.c,v 1.12 93/09/28 08:31:56 leres Exp  (LBL)
 */

/*
 * RPC functions used by NFS and bootparams.
 * Note that bootparams requires the ability to find out the
 * address of the server from which its response has come.
 * This is supported by keeping the IP/UDP headers in the
 * buffer space provided by the caller.  (See rpc_fromaddr)
 */

#include <sys/param.h>
#include <sys/socket.h>

#include <netinet/in.h>
#include <netinet/in_systm.h>

#include <string.h>

#include "rpcv2.h"

#include "stand.h"
#include "net.h"
#include "netif.h"
#include "rpc.h"

struct auth_info {
        int32_t         authtype;       /* auth type */
        u_int32_t       authlen;        /* auth length */
};

struct auth_unix {
        int32_t   ua_time;
        int32_t   ua_hostname;  /* null */
        int32_t   ua_uid;
        int32_t   ua_gid;
        int32_t   ua_gidlist;   /* null */
};

struct rpc_call {
        u_int32_t       rp_xid;         /* request transaction id */
        int32_t         rp_direction;   /* call direction (0) */
        u_int32_t       rp_rpcvers;     /* rpc version (2) */
        u_int32_t       rp_prog;        /* program */
        u_int32_t       rp_vers;        /* version */
        u_int32_t       rp_proc;        /* procedure */
};

struct rpc_reply {
        u_int32_t       rp_xid;         /* request transaction id */
        int32_t         rp_direction;   /* call direction (1) */
        int32_t         rp_astatus;     /* accept status (0: accepted) */
        union {
                u_int32_t       rpu_errno;
                struct {
                        struct auth_info rok_auth;
                        u_int32_t       rok_status;
                } rpu_rok;
        } rp_u;
};

/* Local forwards */
static  ssize_t recvrpc(struct iodesc *, void *, size_t, time_t);
static  int rpc_getport(struct iodesc *, n_long, n_long);

int rpc_xid;
static int rpc_port = 0x400;

int
rpc_newport(void)
{
        if (rpc_port <= 256)            /* recycle after a while */
                rpc_port = 0x400;
        return (--rpc_port);
}

/*
 * Make a rpc call; return length of answer
 * Note: Caller must leave room for headers.
 */
ssize_t
rpc_call(struct iodesc *d, n_long prog, n_long vers, n_long proc, void *sdata,
         size_t slen, void *rdata, size_t rlen)
{
        ssize_t cc;
        struct auth_info *auth;
        struct rpc_call *call;
        struct rpc_reply *reply;
        char *send_head, *send_tail;
        char *recv_head, *recv_tail;
        n_long x;
        int port;       /* host order */

#ifdef RPC_DEBUG
        if (debug)
                printf("rpc_call: prog=0x%x vers=%d proc=%d\n",
                    prog, vers, proc);
#endif

        port = rpc_getport(d, prog, vers);
        if (port == -1)
                return (-1);

        d->destport = htons(port);

        /*
         * Prepend authorization stuff and headers.
         * Note, must prepend things in reverse order.
         */
        send_head = sdata;
        send_tail = (char *)sdata + slen;

        /* Auth verifier is always auth_null */
        send_head -= sizeof(*auth);
        auth = (struct auth_info *)send_head;
        auth->authtype = htonl(RPCAUTH_NULL);
        auth->authlen = 0;

#if 1
        /* Auth credentials: always auth unix (as root) */
        send_head -= sizeof(struct auth_unix);
        bzero(send_head, sizeof(struct auth_unix));
        send_head -= sizeof(*auth);
        auth = (struct auth_info *)send_head;
        auth->authtype = htonl(RPCAUTH_UNIX);
        auth->authlen = htonl(sizeof(struct auth_unix));
#else
        /* Auth credentials: always auth_null (XXX OK?) */
        send_head -= sizeof(*auth);
        auth = send_head;
        auth->authtype = htonl(RPCAUTH_NULL);
        auth->authlen = 0;
#endif

        /* RPC call structure. */
        send_head -= sizeof(*call);
        call = (struct rpc_call *)send_head;
        rpc_xid++;
        call->rp_xid       = htonl(rpc_xid);
        call->rp_direction = htonl(RPC_CALL);
        call->rp_rpcvers   = htonl(RPC_VER2);
        call->rp_prog = htonl(prog);
        call->rp_vers = htonl(vers);
        call->rp_proc = htonl(proc);

        /* Make room for the rpc_reply header. */
        recv_head = rdata;
        recv_tail = (char *)rdata + rlen;
        recv_head -= sizeof(*reply);

        cc = sendrecv(d,
            sendudp, send_head, send_tail - send_head,
            recvrpc, recv_head, recv_tail - recv_head);

#ifdef RPC_DEBUG
        if (debug)
                printf("callrpc: cc=%ld rlen=%lu\n", (long)cc, (u_long)rlen);
#endif
        if (cc == -1)
                return (-1);

        if (cc <= sizeof(*reply)) {
                errno = EBADRPC;
                return (-1);
        }

        recv_tail = recv_head + cc;

        /*
         * Check the RPC reply status.
         * The xid, dir, astatus were already checked.
         */
        reply = (struct rpc_reply *)recv_head;
        auth = &reply->rp_u.rpu_rok.rok_auth;
        x = ntohl(auth->authlen);
        if (x != 0) {
#ifdef RPC_DEBUG
                if (debug)
                        printf("callrpc: reply auth != NULL\n");
#endif
                errno = EBADRPC;
                return(-1);
        }
        x = ntohl(reply->rp_u.rpu_rok.rok_status);
        if (x != 0) {
                printf("callrpc: error = %ld\n", (long)x);
                errno = EBADRPC;
                return(-1);
        }
        recv_head += sizeof(*reply);

        return (ssize_t)(recv_tail - recv_head);
}

/*
 * Returns true if packet is the one we're waiting for.
 * This just checks the XID, direction, acceptance.
 * Remaining checks are done by callrpc
 */
static ssize_t
recvrpc(struct iodesc *d, void *pkt, size_t len, time_t tleft)
{
        struct rpc_reply *reply;
        ssize_t n;
        int     x;

        errno = 0;
#ifdef RPC_DEBUG
        if (debug)
                printf("recvrpc: called len=%lu\n", (u_long)len);
#endif

        n = readudp(d, pkt, len, tleft);
        if (n <= (4 * 4))
                return -1;

        reply = (struct rpc_reply *)pkt;

        x = ntohl(reply->rp_xid);
        if (x != rpc_xid) {
#ifdef RPC_DEBUG
                if (debug)
                        printf("recvrpc: rp_xid %d != xid %d\n", x, rpc_xid);
#endif
                return -1;
        }

        x = ntohl(reply->rp_direction);
        if (x != RPC_REPLY) {
#ifdef RPC_DEBUG
                if (debug)
                        printf("recvrpc: rp_direction %d != REPLY\n", x);
#endif
                return -1;
        }

        x = ntohl(reply->rp_astatus);
        if (x != RPC_MSGACCEPTED) {
                errno = ntohl(reply->rp_u.rpu_errno);
                printf("recvrpc: reject, astat=%d, errno=%d\n", x, errno);
                return -1;
        }

        /* Return data count (thus indicating success) */
        return (n);
}

/*
 * Given a pointer to a reply just received,
 * dig out the IP address/port from the headers.
 */
void
rpc_fromaddr(void *pkt, struct in_addr *addr, u_short *port)
{
        struct hackhdr {
                /* Tail of IP header: just IP addresses */
                n_long ip_src;
                n_long ip_dst;
                /* UDP header: */
                u_int16_t uh_sport;             /* source port */
                u_int16_t uh_dport;             /* destination port */
                int16_t   uh_ulen;              /* udp length */
                u_int16_t uh_sum;               /* udp checksum */
                /* RPC reply header: */
                struct rpc_reply rpc;
        } *hhdr;

        hhdr = ((struct hackhdr *)pkt) - 1;
        addr->s_addr = hhdr->ip_src;
        *port = hhdr->uh_sport;
}

/*
 * RPC Portmapper cache
 */
#define PMAP_NUM 8                      /* need at most 5 pmap entries */

int rpc_pmap_num;
struct pmap_list {
        struct in_addr  addr;   /* server, net order */
        u_int   prog;           /* host order */
        u_int   vers;           /* host order */
        int     port;           /* host order */
} rpc_pmap_list[PMAP_NUM];

/* 
 * return port number in host order, or -1 
 *
 * Parameters:
 *      addr:   server, net order
 *      prog:   host order
 *      vers:   host order
 */
int
rpc_pmap_getcache(struct in_addr addr, u_int prog, u_int vers)
{
        struct pmap_list *pl;

        for (pl = rpc_pmap_list; pl < &rpc_pmap_list[rpc_pmap_num]; pl++) {
                if (pl->addr.s_addr == addr.s_addr &&
                        pl->prog == prog && pl->vers == vers )
                {
                        return (pl->port);
                }
        }
        return (-1);
}

/*
 * Parameters:
 *      addr:   server, net order
 *      prog:   host order
 *      vers:   host order
 *      port:   host order
 */
void
rpc_pmap_putcache(struct in_addr addr, u_int prog, u_int vers, int port)
{
        struct pmap_list *pl;

        /* Don't overflow cache... */
        if (rpc_pmap_num >= PMAP_NUM) {
                /* ... just re-use the last entry. */
                rpc_pmap_num = PMAP_NUM - 1;
#ifdef  RPC_DEBUG
                printf("rpc_pmap_putcache: cache overflow\n");
#endif
        }

        pl = &rpc_pmap_list[rpc_pmap_num];
        rpc_pmap_num++;

        /* Cache answer */
        pl->addr = addr;
        pl->prog = prog;
        pl->vers = vers;
        pl->port = port;
}


/*
 * Request a port number from the port mapper.
 * Returns the port in host order.
 *
 * Parameters:
 *      prog:   host order
 *      vers:   host order
 */
int
rpc_getport(struct iodesc *d, n_long prog, n_long vers)
{
        struct args {
                n_long  prog;           /* call program */
                n_long  vers;           /* call version */
                n_long  proto;          /* call protocol */
                n_long  port;           /* call port (unused) */
        } *args;
        struct res {
                n_long port;
        } *res;
        struct {
                n_long  h[RPC_HEADER_WORDS];
                struct args d;
        } sdata;
        struct {
                n_long  h[RPC_HEADER_WORDS];
                struct res d;
                n_long  pad;
        } rdata;
        ssize_t cc;
        int port;

#ifdef RPC_DEBUG
        if (debug)
                printf("getport: prog=0x%x vers=%d\n", prog, vers);
#endif

        /* This one is fixed forever. */
        if (prog == PMAPPROG)
                return (PMAPPORT);

        /* Try for cached answer first */
        port = rpc_pmap_getcache(d->destip, prog, vers);
        if (port != -1)
                return (port);

        args = &sdata.d;
        args->prog = htonl(prog);
        args->vers = htonl(vers);
        args->proto = htonl(IPPROTO_UDP);
        args->port = 0;
        res = &rdata.d;

        cc = rpc_call(d, PMAPPROG, PMAPVERS, PMAPPROC_GETPORT,
                args, sizeof(*args), res, sizeof(*res));
        if (cc < sizeof(*res)) {
                printf("getport: %s", strerror(errno));
                errno = EBADRPC;
                return (-1);
        }
        port = (int)ntohl(res->port);

        rpc_pmap_putcache(d->destip, prog, vers, port);

        return (port);
}