/*      $NetBSD: tftp.c,v 1.4 1997/09/17 16:57:07 drochner Exp $         */

/*
 * Copyright (c) 1996
 *      Matthias Drochner.  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 for the NetBSD Project
 *      by Matthias Drochner.
 * 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 AUTHOR ``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 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.
 *
 * $FreeBSD: src/lib/libstand/tftp.c,v 1.2.6.4 2001/07/14 14:00:03 mikeh Exp $
 */

/*
 * Simple TFTP implementation for libsa.
 * Assumes:
 *  - socket descriptor (int) at open_file->f_devdata
 *  - server host IP in global servip
 * Restrictions:
 *  - read only
 *  - lseek only with SEEK_SET or SEEK_CUR
 *  - no big time differences between transfers (<tftp timeout)
 */

#include <sys/param.h>
#include <sys/stat.h>
#include <netinet/in.h>
#include <netinet/udp.h>
#include <netinet/ip.h>
#include <netinet/in_systm.h>
#include <arpa/tftp.h>

#include <string.h>

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

#include "tftp.h"

static int      tftp_open(const char *path, struct open_file *f);
static int      tftp_close(struct open_file *f);
static int      tftp_read(struct open_file *f, void *buf, size_t size, size_t *resid);
static int      tftp_write(struct open_file *f, void *buf, size_t size, size_t *resid);
static off_t    tftp_seek(struct open_file *f, off_t offset, int where);
static int      tftp_stat(struct open_file *f, struct stat *sb);

struct fs_ops tftp_fsops = {
        "tftp",
        tftp_open,
        tftp_close,
        tftp_read,
        tftp_write,
        tftp_seek,
        tftp_stat,
        null_readdir
};

extern struct in_addr servip;

static int      tftpport = 2000;

#define RSPACE 520              /* max data packet, rounded up */

struct tftp_handle {
        struct iodesc  *iodesc;
        int             currblock;      /* contents of lastdata */
        int             islastblock;    /* flag */
        int             validsize;
        int             off;
        char           *path;   /* saved for re-requests */
        struct {
                u_char header[HEADER_SIZE];
                struct tftphdr t;
                u_char space[RSPACE];
        } __packed __aligned(4) lastdata;
};

static int tftperrors[8] = {
        0,                      /* ??? */
        ENOENT,
        EPERM,
        ENOSPC,
        EINVAL,                 /* ??? */
        EINVAL,                 /* ??? */
        EEXIST,
        EINVAL                  /* ??? */
};

static ssize_t 
recvtftp(struct iodesc *d, void *pkt, size_t max_len, time_t tleft)
{
        struct tftphdr *t;
        ssize_t len;
        ssize_t tmp_len;

        /*
         * Note: errno of 0 with -1 return means udp poll failed or
         * packet was not for us.
         *
         * We may end up broadcasting the initial TFTP request.  Take the
         * first DATA result and save any ERROR result in case we do not
         * get a DATA.
         */
        errno = 0;
        bzero(pkt, max_len);
        if (d->xid == 1) {
                len = -1;
                while ((tmp_len = readudp(d, pkt, max_len, tleft)) > 0) {
                        len = tmp_len;
                        t = (struct tftphdr *)pkt;
                        if (ntohs(t->th_opcode) == DATA)
                                break;
                }
        } else {
                len = readudp(d, pkt, max_len, tleft);
        }
        if ((int)len < (int)sizeof(*t))
                return (-1);
        t = (struct tftphdr *)pkt;
        errno = 0;

        switch (ntohs(t->th_opcode)) {
        case DATA: {
                int got;

                if (htons(t->th_block) != (uint16_t)d->xid) {
                        /*
                         * Expected block?
                         */
                        return (-1);
                }
                if (d->xid == 1) {
                        /*
                         * First data packet from new port.  Set destip in
                         * case we got replies from multiple hosts, so only
                         * one host is selected.
                         */
                        struct udphdr *uh;
                        struct ip *ip;

                        uh = (struct udphdr *) pkt - 1;
                        ip = (struct ip *)uh - 1;
                        d->destport = uh->uh_sport;
                        d->destip = ip->ip_src;
                } /* else check uh_sport has not changed??? */
                got = len - (t->th_data - (char *)t);
                return got;
        }
        case ERROR:
                if ((unsigned) ntohs(t->th_code) >= 8) {
                        printf("illegal tftp error %d\n", ntohs(t->th_code));
                        errno = EIO;
                } else {
#ifdef DEBUG
                        printf("tftp-error %d\n", ntohs(t->th_code));
#endif
                        errno = tftperrors[ntohs(t->th_code)];
                }
                return (-1);
        default:
#ifdef DEBUG
                printf("tftp type %d not handled\n", ntohs(t->th_opcode));
#endif
                return (-1);
        }
}

/* send request, expect first block (or error) */
static int 
tftp_makereq(struct tftp_handle *h)
{
        struct {
                u_char header[HEADER_SIZE];
                struct tftphdr  t;
                u_char space[FNAME_SIZE + 6];
        } __packed __aligned(4) wbuf;
        char           *wtail;
        int             l;
        ssize_t         res;
        struct tftphdr *t;

        wbuf.t.th_opcode = htons((u_short) RRQ);
        wtail = wbuf.t.th_stuff;
        l = strlen(h->path);
        bcopy(h->path, wtail, l + 1);
        wtail += l + 1;
        bcopy("octet", wtail, 6);
        wtail += 6;

        t = &h->lastdata.t;

        /* h->iodesc->myport = htons(--tftpport); */
        h->iodesc->myport = htons(tftpport + (getsecs() & 0x3ff));
        h->iodesc->destport = htons(IPPORT_TFTP);
        h->iodesc->xid = 1;     /* expected block */

        res = sendrecv(h->iodesc, sendudp, &wbuf.t, wtail - (char *) &wbuf.t,
                       recvtftp, t, sizeof(*t) + RSPACE);

        if (res == -1)
                return (errno);

        h->currblock = 1;
        h->validsize = res;
        h->islastblock = 0;
        if (res < SEGSIZE)
                h->islastblock = 1;     /* very short file */
        return (0);
}

/* ack block, expect next */
static int 
tftp_getnextblock(struct tftp_handle *h)
{
        struct {
                u_char header[HEADER_SIZE];
                struct tftphdr t;
        } __packed __aligned(4) wbuf;
        char           *wtail;
        int             res;
        struct tftphdr *t;

        /*
         * Ack previous block
         */
        wbuf.t.th_opcode = htons((u_short) ACK);
        wtail = (char *) &wbuf.t.th_block;
        wbuf.t.th_block = htons((u_short) h->currblock);
        wtail += 2;

        t = &h->lastdata.t;

        h->iodesc->xid = h->currblock + 1;      /* expected block */

        res = sendrecv(h->iodesc, sendudp, &wbuf.t, wtail - (char *) &wbuf.t,
                       recvtftp, t, sizeof(*t) + RSPACE);

        if (res == -1)          /* 0 is OK! */
                return (errno);

        h->currblock++;
        h->validsize = res;
        if (res < SEGSIZE)
                h->islastblock = 1;     /* EOF */
        return (0);
}

static int 
tftp_open(const char *path, struct open_file *f)
{
        struct tftp_handle *tftpfile;
        struct iodesc  *io;
        int             res;

        /* Avoid trying out tftp_open for disk devices in the EFI loader */
#ifndef __i386__
        if (strcmp(f->f_dev->dv_name, "net") != 0)
                return (EINVAL);
#endif

        tftpfile = (struct tftp_handle *) malloc(sizeof(*tftpfile));
        if (!tftpfile)
                return (ENOMEM);

        tftpfile->iodesc = io = socktodesc(*(int *) (f->f_devdata));
        if (io == NULL) {
                free(tftpfile);
                return (EINVAL);
        }

        io->destip = servip;
        tftpfile->off = 0;
        tftpfile->path = strdup(path);
        if (tftpfile->path == NULL) {
            free(tftpfile);
            return(ENOMEM);
        }

        res = tftp_makereq(tftpfile);

        if (res) {
                free(tftpfile->path);
                free(tftpfile);
                return (res);
        }
        f->f_fsdata = (void *) tftpfile;
        return (0);
}

/*
 * Parameters:
 *      resid:  out
 */
static int 
tftp_read(struct open_file *f, void *addr, size_t size, size_t *resid)
{
        struct tftp_handle *tftpfile;
        static int      tc = 0;
        tftpfile = (struct tftp_handle *) f->f_fsdata;

        while (size > 0) {
                int needblock, count;

                if (!(tc++ % 256))
                        twiddle();

                needblock = tftpfile->off / SEGSIZE + 1;

                if (tftpfile->currblock > needblock)    /* seek backwards */
                        tftp_makereq(tftpfile); /* no error check, it worked
                                                 * for open */

                while (tftpfile->currblock < needblock) {
                        int res;

                        res = tftp_getnextblock(tftpfile);
                        if (res) {      /* no answer */
#ifdef DEBUG
                                printf("tftp: read error\n");
#endif
                                return (res);
                        }
                        if (tftpfile->islastblock)
                                break;
                }

                if (tftpfile->currblock == needblock) {
                        int offinblock, inbuffer;

                        offinblock = tftpfile->off % SEGSIZE;

                        inbuffer = tftpfile->validsize - offinblock;
                        if (inbuffer < 0) {
#ifdef DEBUG
                                printf("tftp: invalid offset %d\n",
                                    tftpfile->off);
#endif
                                return (EINVAL);
                        }
                        count = (size < inbuffer ? size : inbuffer);
                        bcopy(tftpfile->lastdata.t.th_data + offinblock,
                              addr, count);

                        addr = (char *)addr + count;
                        tftpfile->off += count;
                        size -= count;

                        if ((tftpfile->islastblock) && (count == inbuffer))
                                break;  /* EOF */
                } else {
#ifdef DEBUG
                        printf("tftp: block %d not found\n", needblock);
#endif
                        return (EINVAL);
                }

        }

        if (resid)
                *resid = size;
        return (0);
}

static int 
tftp_close(struct open_file *f)
{
        struct tftp_handle *tftpfile;
        tftpfile = (struct tftp_handle *) f->f_fsdata;

        /* let it time out ... */
        f->f_fsdata = NULL;
        if (tftpfile) {
                free(tftpfile->path);
                free(tftpfile);
                f->f_fsdata = NULL;
        }
        return (0);
}

/*
 * Parameters:
 *      resid:  out
 */
static int 
tftp_write(struct open_file *f, void *start, size_t size, size_t *resid)
{
        return (EROFS);
}

static int 
tftp_stat(struct open_file *f, struct stat *sb)
{
        sb->st_mode = 0444 | S_IFREG;
        sb->st_nlink = 1;
        sb->st_uid = 0;
        sb->st_gid = 0;
        sb->st_size = -1;
        return (0);
}

static off_t 
tftp_seek(struct open_file *f, off_t offset, int where)
{
        struct tftp_handle *tftpfile;
        tftpfile = (struct tftp_handle *) f->f_fsdata;

        switch (where) {
        case SEEK_SET:
                tftpfile->off = offset;
                break;
        case SEEK_CUR:
                tftpfile->off += offset;
                break;
        default:
                errno = EOFFSET;
                return (-1);
        }
        return (tftpfile->off);
}