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/* $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.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
/*
* Simple TFTP implementation for libsa.
* Assumes:
* - socket descriptor (int) at dev->d_opendata, dev stored at
* open_file->f_devdata
* - server host IP in global rootip
* 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
};
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';
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 devdesc *dev;
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;
dev = f->f_devdata;
tftpfile->iodesc = io = socktodesc(*(int *)(dev->d_opendata));
if (io == NULL) {
free(tftpfile);
return (EINVAL);
}
io->destip = rootip;
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' && 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') {
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);
}