/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2000-2001 Boris Popov
 * All rights reserved.
 *
 * 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
 */

#include <sys/param.h>
#include <sys/condvar.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/poll.h>
#include <sys/proc.h>
#include <sys/protosw.h>
#include <sys/signalvar.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/sx.h>
#include <sys/sysctl.h>
#include <sys/systm.h>
#include <sys/uio.h>

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

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

#include <sys/mchain.h>

#include <netsmb/netbios.h>

#include <netsmb/smb.h>
#include <netsmb/smb_conn.h>
#include <netsmb/smb_tran.h>
#include <netsmb/smb_trantcp.h>
#include <netsmb/smb_subr.h>

#define M_NBDATA        M_PCB

static int smb_tcpsndbuf = NB_SNDQ - 1;
static int smb_tcprcvbuf = NB_RCVQ - 1;

SYSCTL_DECL(_net_smb);
SYSCTL_INT(_net_smb, OID_AUTO, tcpsndbuf, CTLFLAG_RW, &smb_tcpsndbuf, 0, "");
SYSCTL_INT(_net_smb, OID_AUTO, tcprcvbuf, CTLFLAG_RW, &smb_tcprcvbuf, 0, "");

#define nb_sosend(so,m,flags,td) sosend(so, NULL, 0, m, 0, flags, td)

static int  nbssn_recv(struct nbpcb *nbp, struct mbuf **mpp, int *lenp,
        u_int8_t *rpcodep, struct thread *td);
static int  smb_nbst_disconnect(struct smb_vc *vcp, struct thread *td);

static int
nb_setsockopt_int(struct socket *so, int level, int name, int val)
{
        struct sockopt sopt;
        int error;

        bzero(&sopt, sizeof(sopt));
        sopt.sopt_level = level;
        sopt.sopt_name = name;
        sopt.sopt_val = &val;
        sopt.sopt_valsize = sizeof(val);
        CURVNET_SET(so->so_vnet);
        error = sosetopt(so, &sopt);
        CURVNET_RESTORE();
        return error;
}

static int
nb_intr(struct nbpcb *nbp, struct proc *p)
{
        return 0;
}

static int
nb_upcall(struct socket *so, void *arg, int waitflag)
{
        struct nbpcb *nbp = arg;

        if (arg == NULL || nbp->nbp_selectid == NULL)
                return (SU_OK);
        wakeup(nbp->nbp_selectid);
        return (SU_OK);
}

static int
nb_sethdr(struct mbuf *m, u_int8_t type, u_int32_t len)
{
        u_int32_t *p = mtod(m, u_int32_t *);

        *p = htonl((len & 0x1FFFF) | (type << 24));
        return 0;
}

static int
nb_put_name(struct mbchain *mbp, struct sockaddr_nb *snb)
{
        int error;
        u_char seglen, *cp;

        cp = snb->snb_name;
        if (*cp == 0)
                return EINVAL;
        NBDEBUG("[%s]\n", cp);
        for (;;) {
                seglen = (*cp) + 1;
                error = mb_put_mem(mbp, cp, seglen, MB_MSYSTEM);
                if (error)
                        return error;
                if (seglen == 1)
                        break;
                cp += seglen;
        }
        return 0;
}

static int
nb_connect_in(struct nbpcb *nbp, struct sockaddr_in *to, struct thread *td)
{
        struct socket *so;
        int error, s;

        error = socreate(AF_INET, &so, SOCK_STREAM, IPPROTO_TCP,
            td->td_ucred, td);
        if (error)
                return error;
        nbp->nbp_tso = so;
        SOCKBUF_LOCK(&so->so_rcv);
        soupcall_set(so, SO_RCV, nb_upcall, nbp);
        SOCKBUF_UNLOCK(&so->so_rcv);
        so->so_rcv.sb_timeo = (5 * SBT_1S);
        so->so_snd.sb_timeo = (5 * SBT_1S);
        error = soreserve(so, nbp->nbp_sndbuf, nbp->nbp_rcvbuf);
        if (error)
                goto bad;
        nb_setsockopt_int(so, SOL_SOCKET, SO_KEEPALIVE, 1);
        nb_setsockopt_int(so, IPPROTO_TCP, TCP_NODELAY, 1);
        error = soconnect(so, (struct sockaddr*)to, td);
        if (error)
                goto bad;
        s = splnet();
        while ((so->so_state & SS_ISCONNECTING) && so->so_error == 0) {
                tsleep(&so->so_timeo, PSOCK, "nbcon", 2 * hz);
                if ((so->so_state & SS_ISCONNECTING) && so->so_error == 0 &&
                        (error = nb_intr(nbp, td->td_proc)) != 0) {
                        so->so_state &= ~SS_ISCONNECTING;
                        splx(s);
                        goto bad;
                }
        }
        if (so->so_error) {
                error = so->so_error;
                so->so_error = 0;
                splx(s);
                goto bad;
        }
        splx(s);
        return 0;
bad:
        smb_nbst_disconnect(nbp->nbp_vc, td);
        return error;
}

static int
nbssn_rq_request(struct nbpcb *nbp, struct thread *td)
{
        struct mbchain *mbp;
        struct mdchain *mdp;
        struct mbuf *m0;
        struct timeval tv;
        struct sockaddr_in sin;
        u_short port;
        u_int8_t rpcode;
        int error, rplen;

        mbp = malloc(sizeof(struct mbchain), M_NBDATA, M_WAITOK);
        mdp = malloc(sizeof(struct mbchain), M_NBDATA, M_WAITOK);
        error = mb_init(mbp);
        if (error) {
                free(mbp, M_NBDATA);
                free(mdp, M_NBDATA);
                return error;
        }
        mb_put_uint32le(mbp, 0);
        nb_put_name(mbp, nbp->nbp_paddr);
        nb_put_name(mbp, nbp->nbp_laddr);
        nb_sethdr(mbp->mb_top, NB_SSN_REQUEST, mb_fixhdr(mbp) - 4);
        error = nb_sosend(nbp->nbp_tso, mbp->mb_top, 0, td);
        if (!error) {
                nbp->nbp_state = NBST_RQSENT;
        }
        mb_detach(mbp);
        mb_done(mbp);
        free(mbp, M_NBDATA);
        if (error) {
                free(mdp, M_NBDATA);
                return error;
        }
        TIMESPEC_TO_TIMEVAL(&tv, &nbp->nbp_timo);
        error = selsocket(nbp->nbp_tso, POLLIN, &tv, td);
        if (error == EWOULDBLOCK) {     /* Timeout */
                NBDEBUG("initial request timeout\n");
                free(mdp, M_NBDATA);
                return ETIMEDOUT;
        }
        if (error) {                    /* restart or interrupt */
                free(mdp, M_NBDATA);
                return error;
        }
        error = nbssn_recv(nbp, &m0, &rplen, &rpcode, td);
        if (error) {
                NBDEBUG("recv() error %d\n", error);
                free(mdp, M_NBDATA);
                return error;
        }
        /*
         * Process NETBIOS reply
         */
        if (m0)
                md_initm(mdp, m0);
        error = 0;
        do {
                if (rpcode == NB_SSN_POSRESP) {
                        nbp->nbp_state = NBST_SESSION;
                        nbp->nbp_flags |= NBF_CONNECTED;
                        break;
                }
                if (rpcode != NB_SSN_RTGRESP) {
                        error = ECONNABORTED;
                        break;
                }
                if (rplen != 6) {
                        error = ECONNABORTED;
                        break;
                }
                md_get_mem(mdp, (caddr_t)&sin.sin_addr, 4, MB_MSYSTEM);
                md_get_uint16(mdp, &port);
                sin.sin_port = port;
                nbp->nbp_state = NBST_RETARGET;
                smb_nbst_disconnect(nbp->nbp_vc, td);
                error = nb_connect_in(nbp, &sin, td);
                if (!error)
                        error = nbssn_rq_request(nbp, td);
                if (error) {
                        smb_nbst_disconnect(nbp->nbp_vc, td);
                        break;
                }
        } while(0);
        if (m0)
                md_done(mdp);
        free(mdp, M_NBDATA);
        return error;
}

static int
nbssn_recvhdr(struct nbpcb *nbp, int *lenp,
        u_int8_t *rpcodep, int flags, struct thread *td)
{
        struct socket *so = nbp->nbp_tso;
        struct uio auio;
        struct iovec aio;
        u_int32_t len;
        int error;

        aio.iov_base = (caddr_t)&len;
        aio.iov_len = sizeof(len);
        auio.uio_iov = &aio;
        auio.uio_iovcnt = 1;
        auio.uio_segflg = UIO_SYSSPACE;
        auio.uio_rw = UIO_READ;
        auio.uio_offset = 0;
        auio.uio_resid = sizeof(len);
        auio.uio_td = td;
        CURVNET_SET(so->so_vnet);
        error = soreceive(so, (struct sockaddr **)NULL, &auio,
            (struct mbuf **)NULL, (struct mbuf **)NULL, &flags);
        CURVNET_RESTORE();
        if (error)
                return error;
        if (auio.uio_resid > 0) {
                SMBSDEBUG("short reply\n");
                return EPIPE;
        }
        len = ntohl(len);
        *rpcodep = (len >> 24) & 0xFF;
        len &= 0x1ffff;
        if (len > SMB_MAXPKTLEN) {
                SMBERROR("packet too long (%d)\n", len);
                return EFBIG;
        }
        *lenp = len;
        return 0;
}

static int
nbssn_recv(struct nbpcb *nbp, struct mbuf **mpp, int *lenp,
        u_int8_t *rpcodep, struct thread *td)
{
        struct socket *so = nbp->nbp_tso;
        struct uio auio;
        struct mbuf *m, *tm, *im;
        u_int8_t rpcode;
        int len, resid;
        int error, rcvflg;

        if (so == NULL)
                return ENOTCONN;

        if (mpp)
                *mpp = NULL;
        m = NULL;
        for(;;) {
                /*
                 * Poll for a response header.
                 * If we don't have one waiting, return.
                 */
                len = 0;
                rpcode = 0;
                error = nbssn_recvhdr(nbp, &len, &rpcode, MSG_DONTWAIT, td);
                if ((so->so_state & (SS_ISDISCONNECTING | SS_ISDISCONNECTED)) ||
                    (so->so_rcv.sb_state & SBS_CANTRCVMORE)) {
                        nbp->nbp_state = NBST_CLOSED;
                        NBDEBUG("session closed by peer\n");
                        return ECONNRESET;
                }
                if (error)
                        return error;
                if (len == 0 && nbp->nbp_state != NBST_SESSION)
                        break;
                /* no data, try again */
                if (rpcode == NB_SSN_KEEPALIVE)
                        continue;

                /*
                 * Loop, blocking, for data following the response header.
                 *
                 * Note that we can't simply block here with MSG_WAITALL for the
                 * entire response size, as it may be larger than the TCP
                 * slow-start window that the sender employs.  This will result
                 * in the sender stalling until the delayed ACK is sent, then
                 * resuming slow-start, resulting in very poor performance.
                 *
                 * Instead, we never request more than NB_SORECEIVE_CHUNK
                 * bytes at a time, resulting in an ack being pushed by
                 * the TCP code at the completion of each call.
                 */
                resid = len;
                while (resid > 0) {
                        tm = NULL;
                        rcvflg = MSG_WAITALL;
                        bzero(&auio, sizeof(auio));
                        auio.uio_resid = min(resid, NB_SORECEIVE_CHUNK);
                        auio.uio_td = td;
                        resid -= auio.uio_resid;
                        /*
                         * Spin until we have collected everything in
                         * this chunk.
                         */
                        do {
                                rcvflg = MSG_WAITALL;
                                CURVNET_SET(so->so_vnet);
                                error = soreceive(so, (struct sockaddr **)NULL,
                                    &auio, &tm, (struct mbuf **)NULL, &rcvflg);
                                CURVNET_RESTORE();
                        } while (error == EWOULDBLOCK || error == EINTR ||
                                 error == ERESTART);
                        if (error)
                                goto out;
                        /* short return guarantees unhappiness */
                        if (auio.uio_resid > 0) {
                                SMBERROR("packet is shorter than expected\n");
                                error = EPIPE;
                                goto out;
                        }
                        /* append received chunk to previous chunk(s) */
                        if (m == NULL) {
                                m = tm;
                        } else {
                                /*
                                 * Just glue the new chain on the end.
                                 * Consumer will pullup as required.
                                 */
                                for (im = m; im->m_next != NULL; im = im->m_next)
                                        ;
                                im->m_next = tm;
                        }
                }
                /* got a session/message packet? */
                if (nbp->nbp_state == NBST_SESSION &&
                    rpcode == NB_SSN_MESSAGE)
                        break;
                /* drop packet and try for another */
                NBDEBUG("non-session packet %x\n", rpcode);
                if (m) {
                        m_freem(m);
                        m = NULL;
                }
        }

out:
        if (error) {
                if (m)
                        m_freem(m);
                return error;
        }
        if (mpp)
                *mpp = m;
        else
                m_freem(m);
        *lenp = len;
        *rpcodep = rpcode;
        return 0;
}

/*
 * SMB transport interface
 */
static int
smb_nbst_create(struct smb_vc *vcp, struct thread *td)
{
        struct nbpcb *nbp;

        nbp = malloc(sizeof *nbp, M_NBDATA, M_WAITOK);
        bzero(nbp, sizeof *nbp);
        nbp->nbp_timo.tv_sec = 15;      /* XXX: sysctl ? */
        nbp->nbp_state = NBST_CLOSED;
        nbp->nbp_vc = vcp;
        nbp->nbp_sndbuf = smb_tcpsndbuf;
        nbp->nbp_rcvbuf = smb_tcprcvbuf;
        vcp->vc_tdata = nbp;
        return 0;
}

static int
smb_nbst_done(struct smb_vc *vcp, struct thread *td)
{
        struct nbpcb *nbp = vcp->vc_tdata;

        if (nbp == NULL)
                return ENOTCONN;
        smb_nbst_disconnect(vcp, td);
        if (nbp->nbp_laddr)
                free(nbp->nbp_laddr, M_SONAME);
        if (nbp->nbp_paddr)
                free(nbp->nbp_paddr, M_SONAME);
        free(nbp, M_NBDATA);
        return 0;
}

static int
smb_nbst_bind(struct smb_vc *vcp, struct sockaddr *sap, struct thread *td)
{
        struct nbpcb *nbp = vcp->vc_tdata;
        struct sockaddr_nb *snb;
        int error, slen;

        NBDEBUG("\n");
        error = EINVAL;
        do {
                if (nbp->nbp_flags & NBF_LOCADDR)
                        break;
                /*
                 * It is possible to create NETBIOS name in the kernel,
                 * but nothing prevents us to do it in the user space.
                 */
                if (sap == NULL)
                        break;
                slen = sap->sa_len;
                if (slen < NB_MINSALEN)
                        break;
                snb = (struct sockaddr_nb*)sodupsockaddr(sap, M_WAITOK);
                if (snb == NULL) {
                        error = ENOMEM;
                        break;
                }
                nbp->nbp_laddr = snb;
                nbp->nbp_flags |= NBF_LOCADDR;
                error = 0;
        } while(0);
        return error;
}

static int
smb_nbst_connect(struct smb_vc *vcp, struct sockaddr *sap, struct thread *td)
{
        struct nbpcb *nbp = vcp->vc_tdata;
        struct sockaddr_in sin;
        struct sockaddr_nb *snb;
        struct timespec ts1, ts2;
        int error, slen;

        NBDEBUG("\n");
        if (nbp->nbp_tso != NULL)
                return EISCONN;
        if (nbp->nbp_laddr == NULL)
                return EINVAL;
        slen = sap->sa_len;
        if (slen < NB_MINSALEN)
                return EINVAL;
        if (nbp->nbp_paddr) {
                free(nbp->nbp_paddr, M_SONAME);
                nbp->nbp_paddr = NULL;
        }
        snb = (struct sockaddr_nb*)sodupsockaddr(sap, M_WAITOK);
        if (snb == NULL)
                return ENOMEM;
        nbp->nbp_paddr = snb;
        sin = snb->snb_addrin;
        getnanotime(&ts1);
        error = nb_connect_in(nbp, &sin, td);
        if (error)
                return error;
        getnanotime(&ts2);
        timespecsub(&ts2, &ts1, &ts2);
        if (ts2.tv_sec == 0) {
                ts2.tv_sec = 1;
                ts2.tv_nsec = 0;
        }
        timespecadd(&ts2, &ts2, &nbp->nbp_timo);
        timespecadd(&nbp->nbp_timo, &ts2, &nbp->nbp_timo);
        timespecadd(&nbp->nbp_timo, &ts2, &nbp->nbp_timo);      /*  * 4 */
        error = nbssn_rq_request(nbp, td);
        if (error)
                smb_nbst_disconnect(vcp, td);
        return error;
}

static int
smb_nbst_disconnect(struct smb_vc *vcp, struct thread *td)
{
        struct nbpcb *nbp = vcp->vc_tdata;
        struct socket *so;

        if (nbp == NULL || nbp->nbp_tso == NULL)
                return ENOTCONN;
        if ((so = nbp->nbp_tso) != NULL) {
                nbp->nbp_flags &= ~NBF_CONNECTED;
                nbp->nbp_tso = (struct socket *)NULL;
                soshutdown(so, 2);
                soclose(so);
        }
        if (nbp->nbp_state != NBST_RETARGET) {
                nbp->nbp_state = NBST_CLOSED;
        }
        return 0;
}

static int
smb_nbst_send(struct smb_vc *vcp, struct mbuf *m0, struct thread *td)
{
        struct nbpcb *nbp = vcp->vc_tdata;
        int error;

        if (nbp->nbp_state != NBST_SESSION) {
                error = ENOTCONN;
                goto abort;
        }
        M_PREPEND(m0, 4, M_WAITOK);
        nb_sethdr(m0, NB_SSN_MESSAGE, m_fixhdr(m0) - 4);
        error = nb_sosend(nbp->nbp_tso, m0, 0, td);
        return error;
abort:
        if (m0)
                m_freem(m0);
        return error;
}

static int
smb_nbst_recv(struct smb_vc *vcp, struct mbuf **mpp, struct thread *td)
{
        struct nbpcb *nbp = vcp->vc_tdata;
        u_int8_t rpcode;
        int error, rplen;

        nbp->nbp_flags |= NBF_RECVLOCK;
        error = nbssn_recv(nbp, mpp, &rplen, &rpcode, td);
        nbp->nbp_flags &= ~NBF_RECVLOCK;
        return error;
}

static void
smb_nbst_timo(struct smb_vc *vcp)
{
        return;
}

static void
smb_nbst_intr(struct smb_vc *vcp)
{
        struct nbpcb *nbp = vcp->vc_tdata;

        if (nbp == NULL || nbp->nbp_tso == NULL)
                return;
        sorwakeup(nbp->nbp_tso);
        sowwakeup(nbp->nbp_tso);
}

static int
smb_nbst_getparam(struct smb_vc *vcp, int param, void *data)
{
        struct nbpcb *nbp = vcp->vc_tdata;

        switch (param) {
            case SMBTP_SNDSZ:
                *(int*)data = nbp->nbp_sndbuf;
                break;
            case SMBTP_RCVSZ:
                *(int*)data = nbp->nbp_rcvbuf;
                break;
            case SMBTP_TIMEOUT:
                *(struct timespec*)data = nbp->nbp_timo;
                break;
            default:
                return EINVAL;
        }
        return 0;
}

static int
smb_nbst_setparam(struct smb_vc *vcp, int param, void *data)
{
        struct nbpcb *nbp = vcp->vc_tdata;

        switch (param) {
            case SMBTP_SELECTID:
                nbp->nbp_selectid = data;
                break;
            default:
                return EINVAL;
        }
        return 0;
}

/*
 * Check for fatal errors
 */
static int
smb_nbst_fatal(struct smb_vc *vcp, int error)
{
        switch (error) {
            case ENOTCONN:
            case ENETRESET:
            case ECONNABORTED:
                return 1;
        }
        return 0;
}

struct smb_tran_desc smb_tran_nbtcp_desc = {
        SMBT_NBTCP,
        smb_nbst_create, smb_nbst_done,
        smb_nbst_bind, smb_nbst_connect, smb_nbst_disconnect,
        smb_nbst_send, smb_nbst_recv,
        smb_nbst_timo, smb_nbst_intr,
        smb_nbst_getparam, smb_nbst_setparam,
        smb_nbst_fatal
};