/*      $NetBSD: subr_tftproot.c,v 1.26 2024/07/05 04:31:53 rin Exp $ */

/*-
 * Copyright (c) 2007 Emmanuel Dreyfus, 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.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by Emmanuel Dreyfus
 * 4. The name of the author may not be used to endorse or promote
 *    products derived from this software without specific prior written
 *    permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE 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.
 */

/*
 * Download the root RAMdisk through TFTP at root mount time
 */

#include "opt_tftproot.h"
#include "opt_md.h"

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: subr_tftproot.c,v 1.26 2024/07/05 04:31:53 rin Exp $");

#include <sys/param.h>
#include <sys/types.h>
#include <sys/vnode.h>
#include <sys/mount.h>
#include <sys/lwp.h>
#include <sys/kmem.h>
#include <sys/mbuf.h>
#include <sys/socketvar.h>

#include <net/if.h>

#include <dev/md.h>

#include <netinet/in.h>

#include <nfs/rpcv2.h>

#include <nfs/nfsproto.h>
#include <nfs/nfs.h>
#include <nfs/nfsmount.h>
#include <nfs/nfsdiskless.h>
#include <nfs/nfs_var.h>

/*
 * Copied from <lib/libsa/tftp.h>
 */

#define SEGSIZE         512             /* data segment size */

/*
 * Packet types.
 */
#define RRQ     01                      /* read request */
#define WRQ     02                      /* write request */
#define DATA    03                      /* data packet */
#define ACK     04                      /* acknowledgement */
#define ERROR   05                      /* error code */

struct  tftphdr {
        short   th_opcode;              /* packet type */
        union {
                unsigned short tu_block; /* block # */
                short   tu_code;        /* error code */
                char    tu_stuff[1];    /* request packet stuff */
        } th_u;
        char    th_data[1];             /* data or error string */
} __packed;

#define th_block        th_u.tu_block
#define th_code         th_u.tu_code
#define th_stuff        th_u.tu_stuff
#define th_msg          th_data

#define IPPORT_TFTP 69

#ifdef TFTPROOT_DEBUG
#define DPRINTF(x) printf x
#else
#define DPRINTF(x)
#endif

struct tftproot_handle {
        struct nfs_diskless *trh_nd;
        void *trh_base;
        size_t trh_len;
        unsigned short trh_block;
        int trh_flags;
};

#define TRH_FINISHED    1

int tftproot_dhcpboot(device_t);

static int tftproot_getfile(struct tftproot_handle *, struct lwp *);
static int tftproot_recv(struct mbuf **, void *);

int
tftproot_dhcpboot(device_t bootdv)
{
        struct nfs_diskless *nd = NULL;
        struct ifnet *ifp = NULL;
        struct lwp *l;
        struct tftproot_handle trh;
        device_t dv;
        int error = -1;

        if (rootspec != NULL) {
                int s = pserialize_read_enter();
                IFNET_READER_FOREACH(ifp)
                        if (strcmp(rootspec, ifp->if_xname) == 0)
                                break;
                pserialize_read_exit(s);
        }

        if ((ifp == NULL) &&
            (bootdv != NULL && device_class(bootdv) == DV_IFNET)) {
                int s = pserialize_read_enter();
                IFNET_READER_FOREACH(ifp)
                        if (strcmp(device_xname(bootdv), ifp->if_xname) == 0)
                                break;
                pserialize_read_exit(s);
        }

        if (ifp == NULL) {
                DPRINTF(("%s():%d ifp is NULL\n", __func__, __LINE__));
                goto out;
        }

        dv = device_find_by_xname(ifp->if_xname);

        if ((dv == NULL) || (device_class(dv) != DV_IFNET)) {
                DPRINTF(("%s():%d cannot find device for interface %s\n",
                    __func__, __LINE__, ifp->if_xname));
                goto out;
        }

        root_device = dv;

        l = curlwp; /* XXX */

        nd = kmem_zalloc(sizeof(*nd), KM_SLEEP);
        nd->nd_ifp = ifp;
        nd->nd_nomount = 1;

        if ((error = nfs_boot_init(nd, l)) != 0) {
                DPRINTF(("%s():%d nfs_boot_init returned %d\n",
                    __func__, __LINE__, error));
                goto out;
        }

        /*
         * Strip leading "tftp:"
         */
#define PREFIX "tftp:"
        if (strstr(nd->nd_bootfile, PREFIX) == nd->nd_bootfile)
                (void)memmove(nd->nd_bootfile,
                              nd->nd_bootfile + (sizeof(PREFIX) - 1),
                              sizeof(nd->nd_bootfile) - sizeof(PREFIX));
#undef PREFIX

        printf("tftproot: bootfile=%s\n", nd->nd_bootfile);

        memset(&trh, 0, sizeof(trh));
        trh.trh_nd = nd;
        trh.trh_block = 1;

        if ((error = tftproot_getfile(&trh, l)) != 0) {
                DPRINTF(("%s():%d tftproot_getfile returned %d\n",
                    __func__, __LINE__, error));
                goto out;
        }

        error = 0;

out:
        if (nd)
                kmem_free(nd, sizeof(*nd));

        return error;
}

static int
tftproot_getfile(struct tftproot_handle *trh, struct lwp *l)
{
        struct socket *so = NULL;
        struct mbuf *m_serv = NULL;
        struct mbuf *m_outbuf = NULL;
        struct sockaddr_in sin;
        struct tftphdr *tftp;
        size_t packetlen, namelen;
        int error = -1;
        const char octetstr[] = "octet";
        size_t hdrlen = sizeof(*tftp) - sizeof(tftp->th_data);
        char *cp;
        
        if ((error = socreate(AF_INET, &so, SOCK_DGRAM, 0, l, NULL)) != 0) {
                DPRINTF(("%s():%d socreate returned %d\n",
                    __func__, __LINE__, error));
                goto out;
        }

        /*
         * Set timeout
         */
        if ((error = nfs_boot_setrecvtimo(so))) {
                DPRINTF(("%s():%d SO_RCVTIMEO failed %d\n",
                    __func__, __LINE__, error));
                goto out;
        }

        /*
         * Set server address and port
         */
        memcpy(&sin, &trh->trh_nd->nd_root.ndm_saddr, sizeof(sin));
        sin.sin_port = htons(IPPORT_TFTP);

        /*
         * Set send buffer, prepare the TFTP packet
         */
        namelen = strlen(trh->trh_nd->nd_bootfile) + 1;
        packetlen = sizeof(tftp->th_opcode) + namelen + sizeof(octetstr);
        if (packetlen > MSIZE) {
                DPRINTF(("%s():%d boot filename too long (%ld bytes)\n",
                    __func__, __LINE__, (long)namelen));
                error = E2BIG;
                goto out;
        }

        m_outbuf = m_gethdr(M_WAIT, MT_DATA);
        m_clget(m_outbuf, M_WAIT);
        m_outbuf->m_len = packetlen;
        m_outbuf->m_pkthdr.len = packetlen;
        m_reset_rcvif(m_outbuf);

        tftp = mtod(m_outbuf, struct tftphdr *);
        memset(tftp, 0, packetlen);

        tftp->th_opcode = htons((short)RRQ);
        cp = tftp->th_stuff;
        (void)strncpy(cp,  trh->trh_nd->nd_bootfile, namelen);
        cp += namelen;
        (void)strncpy(cp, octetstr, sizeof(octetstr));

        /*
         * Perform the file transfer
         */
        printf("tftproot: download %s:%s ",
            inet_ntoa(sin.sin_addr), trh->trh_nd->nd_bootfile);

        do {
                /*
                 * Show progress for every 200 blocks (100kB)
                 */
#ifndef TFTPROOT_PROGRESS
#define TFTPROOT_PROGRESS 200
#endif
                if ((trh->trh_block % TFTPROOT_PROGRESS) == 0)
                        twiddle();

                /*
                 * Send the packet and receive the answer.
                 * We get the sender address here, which should be
                 * the same server with a different port
                 */
                if ((error = nfs_boot_sendrecv(so, &sin, NULL, m_outbuf,
                    tftproot_recv, NULL, &m_serv, trh, l)) != 0) {
                        DPRINTF(("%s():%d sendrecv failed %d\n",
                            __func__, __LINE__, error));
                        goto out;
                }

                /*
                 * Accommodate the packet length for acks.
                 * This is really needed only on first pass
                 */
                m_outbuf->m_len = hdrlen;
                m_outbuf->m_pkthdr.len = hdrlen;
                tftp->th_opcode = htons((short)ACK);
                tftp->th_block = htons(trh->trh_block);


                /*
                 * Check for termination
                 */
                if (trh->trh_flags & TRH_FINISHED)
                        break;

                trh->trh_block++;
        } while (1/* CONSTCOND */);

        printf("\n");

        /*
         * Ack the last block. Ignore errors, as we already have the whole
         * file.
         */
        if ((error = (*so->so_send)(so, mtod(m_serv, struct sockaddr *), NULL,
            m_outbuf, NULL, 0, l)) != 0) {
                DPRINTF(("%s():%d tftproot: sosend returned %d\n",
                    __func__, __LINE__, error));
        }

        /* Freed by the protocol */
        m_outbuf = NULL;

        /*
         * And use it as the root ramdisk.
         */
        DPRINTF(("%s():%d RAMdisk loaded: %ld@%p\n",
            __func__, __LINE__, trh->trh_len, trh->trh_base));
        md_root_setconf(trh->trh_base, trh->trh_len);

        error = 0;
out:
        m_freem(m_serv);

        m_freem(m_outbuf);

        if (so)
                soclose(so);

        return error;
}

static int
tftproot_recv(struct mbuf **mp, void *ctx)
{
        struct tftproot_handle *trh = ctx;
        struct tftphdr *tftp;
        struct mbuf *m = *mp;
        size_t newlen;
        size_t hdrlen = sizeof(*tftp) - sizeof(tftp->th_data);

        /*
         * Check for short packet
         */
        if (m->m_pkthdr.len < hdrlen) {
                DPRINTF(("%s():%d short reply (%d bytes)\n",
                    __func__, __LINE__, m->m_pkthdr.len));
                return -1;
        }

        /*
         * Check for packet too large for being a TFTP packet
         */
        if (m->m_pkthdr.len > hdrlen + SEGSIZE) {
                DPRINTF(("%s():%d packet too big (%d bytes)\n",
                    __func__, __LINE__, m->m_pkthdr.len));
                return -1;
        }


        /*
         * Examine the TFTP header
         */
        if (m->m_len > sizeof(*tftp)) {
                if ((m = *mp = m_pullup(m, sizeof(*tftp))) == NULL) {
                        DPRINTF(("%s():%d m_pullup failed\n",
                            __func__, __LINE__));
                        return -1;
                }
        }
        tftp = mtod(m, struct tftphdr *);

        /*
         * We handle data or error
         */
        switch(ntohs(tftp->th_opcode)) {
        case DATA:
                break;
                
        case ERROR: {
                char errbuf[SEGSIZE + 1];
                int i;

                for (i = 0; i < SEGSIZE; i++) {
                        if ((tftp->th_data[i] < ' ') ||
                            (tftp->th_data[i] > '~')) {
                                errbuf[i] = '\0';
                                break;
                        }
                        errbuf[i] = tftp->th_data[i];
                }
                errbuf[SEGSIZE] = '\0';

                printf("tftproot: TFTP server returned error %d, %s\n",
                    ntohs(tftp->th_code), errbuf);

                return -1;
                break;
        }

        default:
                DPRINTF(("%s():%d unexpected tftp reply opcode %d\n",
                    __func__, __LINE__, ntohs(tftp->th_opcode)));
                return -1;
                break;
        }

        /*
         * Check for last packet, which does not fill the whole space
         */
        if (m->m_pkthdr.len < hdrlen + SEGSIZE) {
                DPRINTF(("%s():%d last chunk (%d bytes)\n",
                    __func__, __LINE__, m->m_pkthdr.len));
                trh->trh_flags |= TRH_FINISHED;
        }


        if (ntohs(tftp->th_block) != trh->trh_block) {
                DPRINTF(("%s():%d expected block %d, got block %d\n",
                    __func__, __LINE__, trh->trh_block, ntohs(tftp->th_block)));
                return -1;
        }

        /*
         * Grow the receiving buffer to accommodate new data
         */
        newlen = trh->trh_len + (m->m_pkthdr.len - hdrlen);
        if ((trh->trh_base = realloc(trh->trh_base,
            newlen, M_TEMP, M_WAITOK)) == NULL) {
                DPRINTF(("%s():%d failed to realloc %ld bytes\n",
                    __func__, __LINE__, (long)newlen));
                return -1;
        }

        /*
         * Copy the data
         */
        m_copydata(m, hdrlen, m->m_pkthdr.len - hdrlen,
                   (char *)trh->trh_base + trh->trh_len);
        trh->trh_len = newlen;

        return 0;
}