/*      $NetBSD: krpc_subr.c,v 1.44 2024/10/20 14:01:52 mlelstv Exp $   */

/*
 * 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
 *               @(#) Header: rpc.c,v 1.12 93/09/28 08:31:56 leres Exp  (LBL)
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: krpc_subr.c,v 1.44 2024/10/20 14:01:52 mlelstv Exp $");

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/ioctl.h>
#include <sys/proc.h>
#include <sys/mount.h>
#include <sys/mbuf.h>
#include <sys/reboot.h>
#include <sys/socket.h>
#include <sys/socketvar.h>

#include <netinet/in.h>

#include <nfs/rpcv2.h>
#include <nfs/krpc.h>
#include <nfs/xdr_subs.h>
#include <nfs/nfsproto.h> /* XXX NFSX_V3FHMAX for next */
#include <nfs/nfs.h>
#include <nfs/nfsmount.h>
#include <nfs/nfsdiskless.h> /* XXX decl nfs_boot_sendrecv */

/*
 * 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 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  auth_info rpc_auth;
        struct  auth_unix rpc_unix;
        struct  auth_info rpc_verf;
};

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 {
                /* rejected */
                struct {
                        u_int32_t rej_stat;
                        u_int32_t rej_val1;
                        u_int32_t rej_val2;
                } rpu_rej;
                /* accepted */
                struct {
                        struct auth_info rok_auth;
                        u_int32_t       rok_status;
                } rpu_rok;
        } rp_u;
};
#define rp_rstat  rp_u.rpu_rej.rej_stat
#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 */

static int krpccheck(struct mbuf**, void*);

/*
 * 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_int proto, u_int16_t *portp, struct lwp *l)
        /* sin:          server address */
        /* prog, vers, proto:    host order */
        /* portp:        network order */
{
        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_WAIT, 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(proto);
        sdata->port = 0;

        sin->sin_port = htons(PMAPPORT);
        error = krpc_call(sin, PMAPPROG, PMAPVERS,
                                          PMAPPROC_GETPORT, &m, NULL, l);
        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;
}

static int krpccheck(struct mbuf **mp, void *context)
{
        struct rpc_reply *reply;
        struct mbuf *m = *mp;

        /* Does the reply contain at least a header? */
        if (m->m_pkthdr.len < MIN_REPLY_HDR)
                return(-1);
        if (m->m_len < sizeof(struct rpc_reply)) {
                m = *mp = m_pullup(m, sizeof(struct rpc_reply));
                if (m == NULL)
                        return(-1);
        }
        reply = mtod(m, struct rpc_reply *);

        /* Is it the right reply? */
        if (reply->rp_direction != txdr_unsigned(RPC_REPLY))
                return(-1);

        if (reply->rp_xid != txdr_unsigned(*(u_int32_t*)context))
                return(-1);

        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 mbuf **from_p, struct lwp *l)
        /* data:         input/output */
        /* from_p:       output */
{
        struct socket *so;
        struct sockaddr_in sin;
        struct mbuf *m, *mhead, *from;
        struct rpc_call *call;
        struct rpc_reply *reply;
        int error, len;
        static u_int32_t xid = ~0xFF;
        u_int16_t tport;

        /*
         * 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, l, NULL)))
                return error;

        if ((error = nfs_boot_setrecvtimo(so)))
                goto out;

        /*
         * Enable broadcast if necessary.
         */
        if (from_p) {
                if ((error = nfs_boot_enbroadcast(so)))
                        goto out;
        }

        /*
         * Bind the local endpoint to a reserved port,
         * because some NFS servers refuse requests from
         * non-reserved (non-privileged) ports.
         */
        tport = IPPORT_RESERVED;
        do {
                tport--;
                error = nfs_boot_sobind_ipport(so, tport, l);
        } while (error == EADDRINUSE &&
                         tport > IPPORT_RESERVED / 2);
        if (error) {
                printf("bind failed\n");
                goto out;
        }

        /*
         * Setup socket address for the server.
         */
        sin = *sa;

        /*
         * Prepend RPC message header.
         */
        mhead = m_gethdr(M_WAIT, MT_DATA);
        MCLAIM(mhead, &nfs_mowner);
        mhead->m_next = *data;
        call = mtod(mhead, struct rpc_call *);
        mhead->m_len = sizeof(*call);
        memset((void *)call, 0, 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(RPCAUTH_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
         */
        len = 0;
        m = mhead;
        while (m) {
                len += m->m_len;
                m = m->m_next;
        }
        mhead->m_pkthdr.len = len;
        m_reset_rcvif(mhead);

        error = nfs_boot_sendrecv(so, &sin, NULL, mhead, krpccheck, &m, &from,
            &xid, l);
        if (error)
                goto out;

        /* m_pullup() was done in krpccheck() */
        reply = mtod(m, struct rpc_reply *);

        /* Was RPC accepted? (authorization OK) */
        if (reply->rp_astatus != 0) {
                /* Note: This is NOT an error code! */
                error = fxdr_unsigned(u_int32_t, reply->rp_rstat);
                switch (error) {
                    case RPC_MISMATCH:
                        /* .re_status = RPC_VERSMISMATCH; */
                        error = ERPCMISMATCH;
                        break;
                    case RPC_AUTHERR:
                        /* .re_status = RPC_AUTHERROR; */
                        error = EAUTH;
                        break;
                    default:
                        /* unexpected */
                        error = EBADRPC;
                        break;
                }
                goto out;
        }

        /* Did the call succeed? */
        if (reply->rp_status != 0) {
                /* Note: This is NOT an error code! */
                error = fxdr_unsigned(u_int32_t, reply->rp_status);
                switch (error) {
                    case RPC_PROGUNAVAIL:
                        error = EPROGUNAVAIL;
                        break;
                    case RPC_PROGMISMATCH:
                        error = EPROGMISMATCH;
                        break;
                    case RPC_PROCUNAVAIL:
                        error = EPROCUNAVAIL;
                        break;
                    case RPC_GARBAGE:
                    default:
                        error = EBADRPC;
                }
                goto out;
        }

        /*
         * OK, we have received a good reply!
         * Get its length, then strip it off.
         */
        len = sizeof(*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 && error == 0) {
                *from_p = from;
                from = NULL;
        }

 out:
        m_freem(mhead);
        m_freem(from);
        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_get(M_WAIT, MT_DATA);
        if (mlen > MLEN) {
                m_clget(m, M_WAIT);
                if ((m->m_flags & M_EXT) == 0) {
                        (void) m_free(m);       /* There can be only one. */
                        return (NULL);
                }
        }
        xs = mtod(m, struct xdr_string *);
        m->m_len = mlen;
        xs->len = txdr_unsigned(len);
        memcpy(xs->data, str, len);
        return (m);
}

struct mbuf *
xdr_string_decode(struct mbuf *m, char *str, int *len_p)
        /* len_p:                bufsize - 1 */
{
        struct xdr_string *xs;
        int mlen;       /* message length */
        int slen;       /* string length */

        if (m->m_len < 4) {
                m = m_pullup(m, 4);
                if (m == NULL)
                        return (NULL);
        }
        xs = mtod(m, struct xdr_string *);
        slen = fxdr_unsigned(u_int32_t, xs->len);
        mlen = 4 + ((slen + 3) & ~3);

        if (slen > *len_p)
                slen = *len_p;
        m_copydata(m, 4, slen, str);
        m_adj(m, mlen);

        str[slen] = '\0';
        *len_p = slen;

        return (m);
}


/*
 * Inet address in RPC messages
 * (Note, really four ints, NOT chars.  Blech.)
 */
struct xdr_inaddr {
        u_int32_t atype;
        u_int32_t addr[4];
};

struct mbuf *
xdr_inaddr_encode(struct in_addr *ia)
        /* ia:           already in network order */
{
        struct mbuf *m;
        struct xdr_inaddr *xi;
        u_int8_t *cp;
        u_int32_t *ip;

        m = m_get(M_WAIT, MT_DATA);
        xi = mtod(m, struct xdr_inaddr *);
        m->m_len = sizeof(*xi);
        xi->atype = txdr_unsigned(1);
        ip = xi->addr;
        cp = (u_int8_t *)&ia->s_addr;
        *ip++ = txdr_unsigned(*cp++);
        *ip++ = txdr_unsigned(*cp++);
        *ip++ = txdr_unsigned(*cp++);
        *ip++ = txdr_unsigned(*cp++);

        return (m);
}

struct mbuf *
xdr_inaddr_decode(struct mbuf *m, struct in_addr *ia)
        /* ia:           already in network order */
{
        struct xdr_inaddr *xi;
        u_int8_t *cp;
        u_int32_t *ip;

        if (m->m_len < sizeof(*xi)) {
                m = m_pullup(m, sizeof(*xi));
                if (m == NULL)
                        return (NULL);
        }
        xi = mtod(m, struct xdr_inaddr *);
        if (xi->atype != txdr_unsigned(1)) {
                ia->s_addr = INADDR_ANY;
                goto out;
        }
        ip = xi->addr;
        cp = (u_int8_t *)&ia->s_addr;
        *cp++ = fxdr_unsigned(u_int8_t, *ip++);
        *cp++ = fxdr_unsigned(u_int8_t, *ip++);
        *cp++ = fxdr_unsigned(u_int8_t, *ip++);
        *cp++ = fxdr_unsigned(u_int8_t, *ip++);

out:
        m_adj(m, sizeof(*xi));
        return (m);
}