/*      $NetBSD: krpc_subr.c,v 1.12.4.1 1996/06/07 00:52:26 cgd Exp $   */

/*-
 * SPDX-License-Identifier: BSD-4-Clause
 *
 * Copyright (c) 1995 Gordon Ross, Adam Glass
 * 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. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by the University of
 *      California, Lawrence Berkeley Laboratory and its contributors.
 * 4. 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.
 *
 * partially based on:
 *      libnetboot/rpc.c
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/jail.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/proc.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/uio.h>

#include <net/if.h>
#include <net/vnet.h>

#include <netinet/in.h>

#include <rpc/types.h>
#include <rpc/auth.h>
#include <rpc/rpc_msg.h>
#include <nfs/krpc.h>
#include <nfs/xdr_subs.h>

/*
 * Kernel support for Sun RPC
 *
 * Used currently for bootstrapping in nfs diskless configurations.
 */

/*
 * Generic RPC headers
 */

struct auth_info {
        u_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 krpc_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  auth_info rpc_auth;
        struct  auth_unix rpc_unix;
        struct  auth_info rpc_verf;
};

struct krpc_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;
};
#define rp_errno  rp_u.rpu_errno
#define rp_auth   rp_u.rpu_rok.rok_auth
#define rp_status rp_u.rpu_rok.rok_status

#define MIN_REPLY_HDR 16        /* xid, dir, astat, errno */

/*
 * What is the longest we will wait before re-sending a request?
 * Note this is also the frequency of "RPC timeout" messages.
 * The re-send loop count sup linearly to this maximum, so the
 * first complaint will happen after (1+2+3+4+5)=15 seconds.
 */
#define MAX_RESEND_DELAY 5      /* seconds */

/*
 * Call portmap to lookup a port number for a particular rpc program
 * Returns non-zero error on failure.
 */
int
krpc_portmap(struct sockaddr_in *sin, u_int prog, u_int vers, u_int16_t *portp,
    struct thread *td)
{
        struct sdata {
                u_int32_t prog;         /* call program */
                u_int32_t vers;         /* call version */
                u_int32_t proto;        /* call protocol */
                u_int32_t port;         /* call port (unused) */
        } *sdata;
        struct rdata {
                u_int16_t pad;
                u_int16_t port;
        } *rdata;
        struct mbuf *m;
        int error;

        /* The portmapper port is fixed. */
        if (prog == PMAPPROG) {
                *portp = htons(PMAPPORT);
                return 0;
        }

        m = m_get(M_WAITOK, MT_DATA);
        sdata = mtod(m, struct sdata *);
        m->m_len = sizeof(*sdata);

        /* Do the RPC to get it. */
        sdata->prog = txdr_unsigned(prog);
        sdata->vers = txdr_unsigned(vers);
        sdata->proto = txdr_unsigned(IPPROTO_UDP);
        sdata->port = 0;

        sin->sin_port = htons(PMAPPORT);
        error = krpc_call(sin, PMAPPROG, PMAPVERS,
                                          PMAPPROC_GETPORT, &m, NULL, td);
        if (error)
                return error;

        if (m->m_len < sizeof(*rdata)) {
                m = m_pullup(m, sizeof(*rdata));
                if (m == NULL)
                        return ENOBUFS;
        }
        rdata = mtod(m, struct rdata *);
        *portp = rdata->port;

        m_freem(m);
        return 0;
}

/*
 * Do a remote procedure call (RPC) and wait for its reply.
 * If from_p is non-null, then we are doing broadcast, and
 * the address from whence the response came is saved there.
 */
int
krpc_call(struct sockaddr_in *sa, u_int prog, u_int vers, u_int func,
    struct mbuf **data, struct sockaddr **from_p, struct thread *td)
{
        struct socket *so;
        struct sockaddr_in *sin, ssin;
        struct sockaddr *from;
        struct mbuf *m, *mhead;
        struct krpc_call *call;
        struct krpc_reply *reply;
        struct sockopt sopt;
        struct timeval tv;
        struct uio auio;
        int error, rcvflg, timo, secs, len;
        static u_int32_t xid = ~0xFF;
        u_int16_t tport;
        u_int32_t saddr;

        /*
         * Validate address family.
         * Sorry, this is INET specific...
         */
        if (sa->sin_family != AF_INET)
                return (EAFNOSUPPORT);

        /* Free at end if not null. */
        mhead = NULL;
        from = NULL;

        /*
         * Create socket and set its receive timeout.
         */
        if ((error = socreate(AF_INET, &so, SOCK_DGRAM, 0, td->td_ucred, td)))
                return error;

        tv.tv_sec = 1;
        tv.tv_usec = 0;
        bzero(&sopt, sizeof sopt);
        sopt.sopt_dir = SOPT_SET;
        sopt.sopt_level = SOL_SOCKET;
        sopt.sopt_name = SO_RCVTIMEO;
        sopt.sopt_val = &tv;
        sopt.sopt_valsize = sizeof tv;

        if ((error = sosetopt(so, &sopt)) != 0)
                goto out;

        /*
         * Enable broadcast if necessary.
         */
        if (from_p) {
                int on = 1;
                sopt.sopt_name = SO_BROADCAST;
                sopt.sopt_val = &on;
                sopt.sopt_valsize = sizeof on;
                if ((error = sosetopt(so, &sopt)) != 0)
                        goto out;
        }

        /*
         * Bind the local endpoint to a reserved port,
         * because some NFS servers refuse requests from
         * non-reserved (non-privileged) ports.
         */
        sin = &ssin;
        bzero(sin, sizeof *sin);
        sin->sin_len = sizeof(*sin);
        sin->sin_family = AF_INET;
        sin->sin_addr.s_addr = INADDR_ANY;
        tport = IPPORT_RESERVED;
        do {
                tport--;
                sin->sin_port = htons(tport);
                error = sobind(so, (struct sockaddr *)sin, td);
        } while (error == EADDRINUSE &&
                         tport > IPPORT_RESERVED / 2);
        if (error) {
                printf("bind failed\n");
                goto out;
        }

        /*
         * Setup socket address for the server.
         */

        /*
         * Prepend RPC message header.
         */
        mhead = m_gethdr(M_WAITOK, MT_DATA);
        mhead->m_next = *data;
        call = mtod(mhead, struct krpc_call *);
        mhead->m_len = sizeof(*call);
        bzero((caddr_t)call, sizeof(*call));
        /* rpc_call part */
        xid++;
        call->rp_xid = txdr_unsigned(xid);
        /* call->rp_direction = 0; */
        call->rp_rpcvers = txdr_unsigned(2);
        call->rp_prog = txdr_unsigned(prog);
        call->rp_vers = txdr_unsigned(vers);
        call->rp_proc = txdr_unsigned(func);
        /* rpc_auth part (auth_unix as root) */
        call->rpc_auth.authtype = txdr_unsigned(AUTH_UNIX);
        call->rpc_auth.authlen  = txdr_unsigned(sizeof(struct auth_unix));
        /* rpc_verf part (auth_null) */
        call->rpc_verf.authtype = 0;
        call->rpc_verf.authlen  = 0;

        /*
         * Setup packet header
         */
        m_fixhdr(mhead);
        mhead->m_pkthdr.rcvif = NULL;

        /*
         * Send it, repeatedly, until a reply is received,
         * but delay each re-send by an increasing amount.
         * If the delay hits the maximum, start complaining.
         */
        timo = 0;
        for (;;) {
                /* Send RPC request (or re-send). */
                m = m_copym(mhead, 0, M_COPYALL, M_WAITOK);
                error = sosend(so, (struct sockaddr *)sa, NULL, m,
                               NULL, 0, td);
                if (error) {
                        printf("krpc_call: sosend: %d\n", error);
                        goto out;
                }
                m = NULL;

                /* Determine new timeout. */
                if (timo < MAX_RESEND_DELAY)
                        timo++;
                else {
                        saddr = ntohl(sa->sin_addr.s_addr);
                        printf("RPC timeout for server %d.%d.%d.%d\n",
                               (saddr >> 24) & 255,
                               (saddr >> 16) & 255,
                               (saddr >> 8) & 255,
                               saddr & 255);
                }

                /*
                 * Wait for up to timo seconds for a reply.
                 * The socket receive timeout was set to 1 second.
                 */
                secs = timo;
                while (secs > 0) {
                        if (from) {
                                free(from, M_SONAME);
                                from = NULL;
                        }
                        if (m) {
                                m_freem(m);
                                m = NULL;
                        }
                        bzero(&auio, sizeof(auio));
                        auio.uio_resid = len = 1<<16;
                        rcvflg = 0;
                        error = soreceive(so, &from, &auio, &m, NULL, &rcvflg);
                        if (error == EWOULDBLOCK) {
                                secs--;
                                continue;
                        }
                        if (error)
                                goto out;
                        len -= auio.uio_resid;

                        /* Does the reply contain at least a header? */
                        if (len < MIN_REPLY_HDR)
                                continue;
                        if (m->m_len < MIN_REPLY_HDR)
                                continue;
                        reply = mtod(m, struct krpc_reply *);

                        /* Is it the right reply? */
                        if (reply->rp_direction != txdr_unsigned(REPLY))
                                continue;

                        if (reply->rp_xid != txdr_unsigned(xid))
                                continue;

                        /* Was RPC accepted? (authorization OK) */
                        if (reply->rp_astatus != 0) {
                                error = fxdr_unsigned(u_int32_t, reply->rp_errno);
                                printf("rpc denied, error=%d\n", error);
                                continue;
                        }

                        /* Did the call succeed? */
                        if (reply->rp_status != 0) {
                                error = fxdr_unsigned(u_int32_t, reply->rp_status);
                                if (error == PROG_MISMATCH) {
                                  error = EBADRPC;
                                  goto out;
                                }
                                printf("rpc denied, status=%d\n", error);
                                continue;
                        }

                        goto gotreply;  /* break two levels */

                } /* while secs */
        } /* forever send/receive */

        error = ETIMEDOUT;
        goto out;

 gotreply:

        /*
         * Get RPC reply header into first mbuf,
         * get its length, then strip it off.
         */
        len = sizeof(*reply);
        if (m->m_len < len) {
                m = m_pullup(m, len);
                if (m == NULL) {
                        error = ENOBUFS;
                        goto out;
                }
        }
        reply = mtod(m, struct krpc_reply *);
        if (reply->rp_auth.authtype != 0) {
                len += fxdr_unsigned(u_int32_t, reply->rp_auth.authlen);
                len = (len + 3) & ~3; /* XXX? */
        }
        m_adj(m, len);

        /* result */
        *data = m;
        if (from_p) {
                *from_p = from;
                from = NULL;
        }

 out:
        if (mhead) m_freem(mhead);
        if (from) free(from, M_SONAME);
        soclose(so);
        return error;
}

/*
 * eXternal Data Representation routines.
 * (but with non-standard args...)
 */

/*
 * String representation for RPC.
 */
struct xdr_string {
        u_int32_t len;          /* length without null or padding */
        char data[4];   /* data (longer, of course) */
    /* data is padded to a long-word boundary */
};

struct mbuf *
xdr_string_encode(char *str, int len)
{
        struct mbuf *m;
        struct xdr_string *xs;
        int dlen;       /* padded string length */
        int mlen;       /* message length */

        dlen = (len + 3) & ~3;
        mlen = dlen + 4;

        if (mlen > MCLBYTES)            /* If too big, we just can't do it. */
                return (NULL);

        m = m_get2(mlen, M_WAITOK, MT_DATA, 0);
        xs = mtod(m, struct xdr_string *);
        m->m_len = mlen;
        xs->len = txdr_unsigned(len);
        bcopy(str, xs->data, len);
        return (m);
}