Super User's BSD Cross Reference: /FreeBSD/stand/libsa/tftp.c

 /* $NetBSD: tftp.c,v 1.4 1997年09月17日 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.
 */

#include <sys/cdefs.h>
 __FBSDID("$FreeBSD$");

 /*
 * 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/types.h>
#include <sys/stat.h>
#include <netinet/in.h>
#include <netinet/udp.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"

 struct tftp_handle;
 struct tftprecv_extra;

 static ssize_t recvtftp(struct iodesc *, void **, void **, time_t, void *);
 static int tftp_open(const char *, struct open_file *);
 static int tftp_close(struct open_file *);
 static int tftp_parse_oack(struct tftp_handle *, char *, size_t);
 static int tftp_read(struct open_file *, void *, size_t, size_t *);
 static off_t tftp_seek(struct open_file *, off_t, int);
 static int tftp_set_blksize(struct tftp_handle *, const char *);
 static int tftp_stat(struct open_file *, struct stat *);

 struct fs_ops tftp_fsops = {
 .fs_name = "tftp",
 .fo_open = tftp_open,
 .fo_close = tftp_close,
 .fo_read = tftp_read,
 .fo_write = null_write,
 .fo_seek = tftp_seek,
 .fo_stat = tftp_stat,
 .fo_readdir = null_readdir
};

 extern struct in_addr servip;

 static int tftpport = 2000;
 static int is_open = 0;

 /*
 * The legacy TFTP_BLKSIZE value was SEGSIZE(512).
 * TFTP_REQUESTED_BLKSIZE of 1428 is (Ethernet MTU, less the TFTP, UDP and
 * IP header lengths).
 */
#define TFTP_REQUESTED_BLKSIZE 1428

 /*
 * Choose a blksize big enough so we can test with Ethernet
 * Jumbo frames in the future.
 */
#define TFTP_MAX_BLKSIZE 9008
#define TFTP_TRIES 2

 struct tftp_handle {
 struct iodesc *iodesc;
 int currblock; /* contents of lastdata */
 int islastblock:1; /* flag */
 int tries:4; /* number of read attempts */
 int validsize;
 int off;
 char *path; /* saved for re-requests */
 unsigned int tftp_blksize;
 unsigned long tftp_tsize;
 void *pkt;
 struct tftphdr *tftp_hdr;
};

 struct tftprecv_extra {
 struct tftp_handle *tftp_handle;
 unsigned short rtype; /* Received type */
};

#define TFTP_MAX_ERRCODE EOPTNEG
 static const int tftperrors[TFTP_MAX_ERRCODE + 1] = {
 0, /* ??? */
 ENOENT,
 EPERM,
 ENOSPC,
 EINVAL, /* ??? */
 EINVAL, /* ??? */
 EEXIST,
 EINVAL, /* ??? */
 EINVAL, /* Option negotiation failed. */
};

 static int tftp_getnextblock(struct tftp_handle *h);

 /* send error message back. */
 static void
 tftp_senderr(struct tftp_handle *h, u_short errcode, const char *msg)
{
 struct {
 u_char header[HEADER_SIZE];
 struct tftphdr t;
 u_char space[63]; /* +1 from t */
 } __packed __aligned(4) wbuf;
 char *wtail;
 int len;

 len = strlen(msg);
 if (len > sizeof(wbuf.space))
 len = sizeof(wbuf.space);

 wbuf.t.th_opcode = htons((u_short)ERROR);
 wbuf.t.th_code = htons(errcode);

 wtail = wbuf.t.th_msg;
 bcopy(msg, wtail, len);
 wtail[len] = '0円';
 wtail += len + 1;

 sendudp(h->iodesc, &wbuf.t, wtail - (char *)&wbuf.t);
}

 static void
 tftp_sendack(struct tftp_handle *h, u_short block)
{
 struct {
 u_char header[HEADER_SIZE];
 struct tftphdr t;
 } __packed __aligned(4) wbuf;
 char *wtail;

 wbuf.t.th_opcode = htons((u_short)ACK);
 wtail = (char *)&wbuf.t.th_block;
 wbuf.t.th_block = htons(block);
 wtail += 2;

 sendudp(h->iodesc, &wbuf.t, wtail - (char *)&wbuf.t);
}

 static ssize_t
 recvtftp(struct iodesc *d, void **pkt, void **payload, time_t tleft,
 void *recv_extra)
{
 struct tftprecv_extra *extra;
 struct tftp_handle *h;
 struct tftphdr *t;
 void *ptr = NULL;
 ssize_t len;

 errno = 0;
 extra = recv_extra;
 h = extra->tftp_handle;

 len = readudp(d, &ptr, (void **)&t, tleft);

 if (len < 4) {
 free(ptr);
 return (-1);
 }

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

 if (htons(t->th_block) < (u_short)d->xid) {
 /*
 * Apparently our ACK was missed, re-send.
 */
 tftp_sendack(h, htons(t->th_block));
 free(ptr);
 return (-1);
 }
 if (htons(t->th_block) != (u_short)d->xid) {
 /*
 * Packet from the future, drop this.
 */
 free(ptr);
 return (-1);
 }
 if (d->xid == 1) {
 /*
 * First data packet from new port.
 */
 struct udphdr *uh;
 uh = (struct udphdr *)t - 1;
 d->destport = uh->uh_sport;
 }
 got = len - (t->th_data - (char *)t);
 *pkt = ptr;
 *payload = t;
 return (got);
 }
 case ERROR:
 if ((unsigned)ntohs(t->th_code) > TFTP_MAX_ERRCODE) {
 printf("illegal tftp error %d\n", ntohs(t->th_code));
 errno = EIO;
 } else {
#ifdef TFTP_DEBUG
 printf("tftp-error %d\n", ntohs(t->th_code));
#endif
 errno = tftperrors[ntohs(t->th_code)];
 }
 free(ptr);
 return (-1);
 case OACK: {
 struct udphdr *uh;
 int tftp_oack_len;

 /*
 * Unexpected OACK. TFTP transfer already in progress.
 * Drop the pkt.
 */
 if (d->xid != 1) {
 free(ptr);
 return (-1);
 }

 /*
 * Remember which port this OACK came from, because we need
 * to send the ACK or errors back to it.
 */
 uh = (struct udphdr *)t - 1;
 d->destport = uh->uh_sport;

 /* Parse options ACK-ed by the server. */
 tftp_oack_len = len - sizeof(t->th_opcode);
 if (tftp_parse_oack(h, t->th_u.tu_stuff, tftp_oack_len) != 0) {
 tftp_senderr(h, EOPTNEG, "Malformed OACK");
 errno = EIO;
 free(ptr);
 return (-1);
 }
 *pkt = ptr;
 *payload = t;
 return (0);
 }
 default:
#ifdef TFTP_DEBUG
 printf("tftp type %d not handled\n", ntohs(t->th_opcode));
#endif
 free(ptr);
 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;
 struct tftprecv_extra recv_extra;
 char *wtail;
 int l;
 ssize_t res;
 void *pkt;
 struct tftphdr *t;
 char *tftp_blksize = NULL;
 int blksize_l;

 /*
 * Allow overriding default TFTP block size by setting
 * a tftp.blksize environment variable.
 */
 if ((tftp_blksize = getenv("tftp.blksize")) != NULL) {
 tftp_set_blksize(h, tftp_blksize);
 }

 wbuf.t.th_opcode = htons((u_short)RRQ);
 wtail = wbuf.t.th_stuff;
 l = strlen(h->path);
#ifdef TFTP_PREPEND_PATH
 if (l > FNAME_SIZE - (sizeof(TFTP_PREPEND_PATH) - 1))
 return (ENAMETOOLONG);
 bcopy(TFTP_PREPEND_PATH, wtail, sizeof(TFTP_PREPEND_PATH) - 1);
 wtail += sizeof(TFTP_PREPEND_PATH) - 1;
#else
 if (l > FNAME_SIZE)
 return (ENAMETOOLONG);
#endif
 bcopy(h->path, wtail, l + 1);
 wtail += l + 1;
 bcopy("octet", wtail, 6);
 wtail += 6;
 bcopy("blksize", wtail, 8);
 wtail += 8;
 blksize_l = sprintf(wtail, "%d", h->tftp_blksize);
 wtail += blksize_l + 1;
 bcopy("tsize", wtail, 6);
 wtail += 6;
 bcopy("0", wtail, 2);
 wtail += 2;

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

 h->currblock = 0;
 h->islastblock = 0;
 h->validsize = 0;

 pkt = NULL;
 recv_extra.tftp_handle = h;
 res = sendrecv(h->iodesc, &sendudp, &wbuf.t, wtail - (char *)&wbuf.t,
 &recvtftp, &pkt, (void **)&t, &recv_extra);
 if (res == -1) {
 free(pkt);
 return (errno);
 }

 free(h->pkt);
 h->pkt = pkt;
 h->tftp_hdr = t;

 if (recv_extra.rtype == OACK)
 return (tftp_getnextblock(h));

 /* Server ignored our blksize request, revert to TFTP default. */
 h->tftp_blksize = SEGSIZE;

 switch (recv_extra.rtype) {
 case DATA: {
 h->currblock = 1;
 h->validsize = res;
 h->islastblock = 0;
 if (res < h->tftp_blksize) {
 h->islastblock = 1; /* very short file */
 tftp_sendack(h, h->currblock);
 }
 return (0);
 }
 case ERROR:
 default:
 return (errno);
 }

}

 /* 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;
 struct tftprecv_extra recv_extra;
 char *wtail;
 int res;
 void *pkt;
 struct tftphdr *t;

 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;

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

 pkt = NULL;
 recv_extra.tftp_handle = h;
 res = sendrecv(h->iodesc, &sendudp, &wbuf.t, wtail - (char *)&wbuf.t,
 &recvtftp, &pkt, (void **)&t, &recv_extra);

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

 free(h->pkt);
 h->pkt = pkt;
 h->tftp_hdr = t;
 h->currblock++;
 h->validsize = res;
 if (res < h->tftp_blksize)
 h->islastblock = 1; /* EOF */

 if (h->islastblock == 1) {
 /* Send an ACK for the last block */
 wbuf.t.th_block = htons((u_short)h->currblock);
 sendudp(h->iodesc, &wbuf.t, wtail - (char *)&wbuf.t);
 }

 return (0);
}

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

 if (netproto != NET_TFTP)
 return (EINVAL);

 if (f->f_dev->dv_type != DEVT_NET)
 return (EINVAL);

 if (is_open)
 return (EBUSY);

 tftpfile = calloc(1, sizeof(*tftpfile));
 if (!tftpfile)
 return (ENOMEM);

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

 io->destip = servip;
 tftpfile->off = 0;
 pathsize = (strlen(rootpath) + 1 + strlen(path) + 1) * sizeof(char);
 tftpfile->path = malloc(pathsize);
 if (tftpfile->path == NULL) {
 free(tftpfile);
 return (ENOMEM);
 }
 if (rootpath[strlen(rootpath) - 1] == '/' || path[0] == '/')
 extraslash = "";
 else
 extraslash = "/";
 res = snprintf(tftpfile->path, pathsize, "%s%s%s",
 rootpath, extraslash, path);
 if (res < 0 || res > pathsize) {
 free(tftpfile->path);
 free(tftpfile);
 return (ENOMEM);
 }

 res = tftp_makereq(tftpfile);

 if (res) {
 free(tftpfile->path);
 free(tftpfile->pkt);
 free(tftpfile);
 return (res);
 }
 f->f_fsdata = tftpfile;
 is_open = 1;
 return (0);
}

 static int
 tftp_read(struct open_file *f, void *addr, size_t size,
 size_t *resid /* out */)
{
 struct tftp_handle *tftpfile;
 size_t res;
 int rc;

 rc = 0;
 res = size;
 tftpfile = f->f_fsdata;

 /* Make sure we will not read past file end */
 if (tftpfile->tftp_tsize > 0 &&
 tftpfile->off + size > tftpfile->tftp_tsize) {
 size = tftpfile->tftp_tsize - tftpfile->off;
 }

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

 twiddle(32);

 needblock = tftpfile->off / tftpfile->tftp_blksize + 1;

 if (tftpfile->currblock > needblock) { /* seek backwards */
 tftp_senderr(tftpfile, 0, "No error: read aborted");
 rc = tftp_makereq(tftpfile);
 if (rc != 0)
 break;
 }

 while (tftpfile->currblock < needblock) {

 rc = tftp_getnextblock(tftpfile);
 if (rc) { /* no answer */
#ifdef TFTP_DEBUG
 printf("tftp: read error\n");
#endif
 if (tftpfile->tries > TFTP_TRIES) {
 return (rc);
 } else {
 tftpfile->tries++;
 tftp_makereq(tftpfile);
 }
 }
 if (tftpfile->islastblock)
 break;
 }

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

 offinblock = tftpfile->off % tftpfile->tftp_blksize;

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

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

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

 }

 if (resid != NULL)
 *resid = res;
 return (rc);
}

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

 /* let it time out ... */

 if (tftpfile) {
 free(tftpfile->path);
 free(tftpfile->pkt);
 free(tftpfile);
 }
 is_open = 0;
 return (0);
}

 static int
 tftp_stat(struct open_file *f, struct stat *sb)
{
 struct tftp_handle *tftpfile;
 tftpfile = f->f_fsdata;

 sb->st_mode = 0444 | S_IFREG;
 sb->st_nlink = 1;
 sb->st_uid = 0;
 sb->st_gid = 0;
 sb->st_size = tftpfile->tftp_tsize;
 return (0);
}

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

 static int
 tftp_set_blksize(struct tftp_handle *h, const char *str)
{
 char *endptr;
 int new_blksize;
 int ret = 0;

 if (h == NULL || str == NULL)
 return (ret);

 new_blksize =
 (unsigned int)strtol(str, &endptr, 0);

 /*
 * Only accept blksize value if it is numeric.
 * RFC2348 specifies that acceptable values are 8-65464.
 * Let's choose a limit less than MAXRSPACE.
 */
 if (*endptr == '0円' && new_blksize >= 8 &&
 new_blksize <= TFTP_MAX_BLKSIZE) {
 h->tftp_blksize = new_blksize;
 ret = 1;
 }

 return (ret);
}

 /*
 * In RFC2347, the TFTP Option Acknowledgement package (OACK)
 * is used to acknowledge a client's option negotiation request.
 * The format of an OACK packet is:
 * +-------+---~~---+---+---~~---+---+---~~---+---+---~~---+---+
 * | opc | opt1 | 0 | value1 | 0 | optN | 0 | valueN | 0 |
 * +-------+---~~---+---+---~~---+---+---~~---+---+---~~---+---+
 *
 * opc
 * The opcode field contains a 6, for Option Acknowledgment.
 *
 * opt1
 * The first option acknowledgment, copied from the original
 * request.
 *
 * value1
 * The acknowledged value associated with the first option. If
 * and how this value may differ from the original request is
 * detailed in the specification for the option.
 *
 * optN, valueN
 * The final option/value acknowledgment pair.
 */
 static int
 tftp_parse_oack(struct tftp_handle *h, char *buf, size_t len)
{
 /*
 * We parse the OACK strings into an array
 * of name-value pairs.
 */
 char *tftp_options[128] = { 0 };
 char *val = buf;
 int i = 0;
 int option_idx = 0;
 int blksize_is_set = 0;
 int tsize = 0;

 unsigned int orig_blksize;

 while (option_idx < 128 && i < len) {
 if (buf[i] == '0円') {
 if (&buf[i] > val) {
 tftp_options[option_idx] = val;
 val = &buf[i] + 1;
 ++option_idx;
 }
 }
 ++i;
 }

 /* Save the block size we requested for sanity check later. */
 orig_blksize = h->tftp_blksize;

 /*
 * Parse individual TFTP options.
 * * "blksize" is specified in RFC2348.
 * * "tsize" is specified in RFC2349.
 */
 for (i = 0; i < option_idx; i += 2) {
 if (strcasecmp(tftp_options[i], "blksize") == 0) {
 if (i + 1 < option_idx)
 blksize_is_set =
 tftp_set_blksize(h, tftp_options[i + 1]);
 } else if (strcasecmp(tftp_options[i], "tsize") == 0) {
 if (i + 1 < option_idx)
 tsize = strtol(tftp_options[i + 1], NULL, 10);
 if (tsize != 0)
 h->tftp_tsize = tsize;
 } else {
 /*
 * Do not allow any options we did not expect to be
 * ACKed.
 */
 printf("unexpected tftp option '%s'\n",
 tftp_options[i]);
 return (-1);
 }
 }

 if (!blksize_is_set) {
 /*
 * If TFTP blksize was not set, try defaulting
 * to the legacy TFTP blksize of SEGSIZE(512)
 */
 h->tftp_blksize = SEGSIZE;
 } else if (h->tftp_blksize > orig_blksize) {
 /*
 * Server should not be proposing block sizes that
 * exceed what we said we can handle.
 */
 printf("unexpected blksize %u\n", h->tftp_blksize);
 return (-1);
 }

#ifdef TFTP_DEBUG
 printf("tftp_blksize: %u\n", h->tftp_blksize);
 printf("tftp_tsize: %lu\n", h->tftp_tsize);
#endif
 return (0);
}
 

Indexes created Mon Nov 10 03:54:35 PST 2025