freebsd-src/libexec/tftpd/tftp-transfer.c
Craig Rodrigues 38bd7db313 In the old TFTP server, there was an undocumented behavior where
the block counter would rollover to 0 if a file larger
than 65535 blocks was transferred.  With the default block size
of 512 octets per block, this is a file size of approximately 32 megabytes.

The new TFTP server code would report an error and stop transferring
the file if a file was larger than 65535 blocks.

This patch restores the old TFTP server's behavior to the new
TFTP server code.  If a TFTP client transfers a file larger
than 65535 blocks, and does *not* specify the "rollover" option,
then automatically rollover the block counter to 0 every time
we reach 65535 blocks.

This restores interoperability with the FreeBSD 6 TFTP client.
Without this change, if a FreeBSD 6 TFTP client tried to
retrieve a file larger than 65535 blocks from a FreeBSD 9 TFTP server
, the transfer would fail.
The same file could be retrieved successfully if the same FreeBSD 6
TFTP client was used against a FreeBSD 6 TFTP server.

Approved by:  re (kib)
Tested by: Pawan Gupta <pawang at juniper dot net>,
Obtained from:  Juniper Networks
2011-07-31 03:12:20 +00:00

323 lines
7.7 KiB
C

/*
* Copyright (C) 2008 Edwin Groothuis. 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 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 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/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/types.h>
#include <sys/param.h>
#include <sys/ioctl.h>
#include <sys/stat.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/tftp.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <syslog.h>
#include "tftp-file.h"
#include "tftp-io.h"
#include "tftp-utils.h"
#include "tftp-options.h"
#include "tftp-transfer.h"
/*
* Send a file via the TFTP data session.
*/
void
tftp_send(int peer, uint16_t *block, struct tftp_stats *ts)
{
struct tftphdr *rp;
int size, n_data, n_ack, try;
uint16_t oldblock;
char sendbuffer[MAXPKTSIZE];
char recvbuffer[MAXPKTSIZE];
rp = (struct tftphdr *)recvbuffer;
*block = 1;
ts->amount = 0;
do {
if (debug&DEBUG_SIMPLE)
tftp_log(LOG_DEBUG, "Sending block %d", *block);
size = read_file(sendbuffer, segsize);
if (size < 0) {
tftp_log(LOG_ERR, "read_file returned %d", size);
send_error(peer, errno + 100);
goto abort;
}
for (try = 0; ; try++) {
n_data = send_data(peer, *block, sendbuffer, size);
if (n_data > 0) {
if (try == maxtimeouts) {
tftp_log(LOG_ERR,
"Cannot send DATA packet #%d, "
"giving up", *block);
return;
}
tftp_log(LOG_ERR,
"Cannot send DATA packet #%d, trying again",
*block);
continue;
}
n_ack = receive_packet(peer, recvbuffer,
MAXPKTSIZE, NULL, timeoutpacket);
if (n_ack < 0) {
if (n_ack == RP_TIMEOUT) {
if (try == maxtimeouts) {
tftp_log(LOG_ERR,
"Timeout #%d send ACK %d "
"giving up", try, *block);
return;
}
tftp_log(LOG_WARNING,
"Timeout #%d on ACK %d",
try, *block);
continue;
}
/* Either read failure or ERROR packet */
if (debug&DEBUG_SIMPLE)
tftp_log(LOG_ERR, "Aborting: %s",
rp_strerror(n_ack));
goto abort;
}
if (rp->th_opcode == ACK) {
ts->blocks++;
if (rp->th_block == *block) {
ts->amount += size;
break;
}
/* Re-synchronize with the other side */
(void) synchnet(peer);
if (rp->th_block == (*block - 1)) {
ts->retries++;
continue;
}
}
}
oldblock = *block;
(*block)++;
if (oldblock > *block) {
if (options[OPT_ROLLOVER].o_request == NULL) {
/*
* "rollover" option not specified in
* tftp client. Default to rolling block
* counter to 0.
*/
*block = 0;
} else {
*block = atoi(options[OPT_ROLLOVER].o_request);
}
ts->rollovers++;
}
gettimeofday(&(ts->tstop), NULL);
} while (size == segsize);
abort:
return;
}
/*
* Receive a file via the TFTP data session.
*
* - It could be that the first block has already arrived while
* trying to figure out if we were receiving options or not. In
* that case it is passed to this function.
*/
void
tftp_receive(int peer, uint16_t *block, struct tftp_stats *ts,
struct tftphdr *firstblock, size_t fb_size)
{
struct tftphdr *rp;
uint16_t oldblock;
int n_data, n_ack, writesize, i, retry;
char recvbuffer[MAXPKTSIZE];
ts->amount = 0;
if (firstblock != NULL) {
writesize = write_file(firstblock->th_data, fb_size);
ts->amount += writesize;
for (i = 0; ; i++) {
n_ack = send_ack(peer, *block);
if (n_ack > 0) {
if (i == maxtimeouts) {
tftp_log(LOG_ERR,
"Cannot send ACK packet #%d, "
"giving up", *block);
return;
}
tftp_log(LOG_ERR,
"Cannot send ACK packet #%d, trying again",
*block);
continue;
}
break;
}
if (fb_size != segsize) {
gettimeofday(&(ts->tstop), NULL);
return;
}
}
rp = (struct tftphdr *)recvbuffer;
do {
oldblock = *block;
(*block)++;
if (oldblock > *block) {
if (options[OPT_ROLLOVER].o_request == NULL) {
/*
* "rollover" option not specified in
* tftp client. Default to rolling block
* counter to 0.
*/
*block = 0;
} else {
*block = atoi(options[OPT_ROLLOVER].o_request);
}
ts->rollovers++;
}
for (retry = 0; ; retry++) {
if (debug&DEBUG_SIMPLE)
tftp_log(LOG_DEBUG,
"Receiving DATA block %d", *block);
n_data = receive_packet(peer, recvbuffer,
MAXPKTSIZE, NULL, timeoutpacket);
if (n_data < 0) {
if (retry == maxtimeouts) {
tftp_log(LOG_ERR,
"Timeout #%d on DATA block %d, "
"giving up", retry, *block);
return;
}
if (n_data == RP_TIMEOUT) {
tftp_log(LOG_WARNING,
"Timeout #%d on DATA block %d",
retry, *block);
send_ack(peer, oldblock);
continue;
}
/* Either read failure or ERROR packet */
if (debug&DEBUG_SIMPLE)
tftp_log(LOG_DEBUG, "Aborting: %s",
rp_strerror(n_data));
goto abort;
}
if (rp->th_opcode == DATA) {
ts->blocks++;
if (rp->th_block == *block)
break;
tftp_log(LOG_WARNING,
"Expected DATA block %d, got block %d",
*block, rp->th_block);
/* Re-synchronize with the other side */
(void) synchnet(peer);
if (rp->th_block == (*block-1)) {
tftp_log(LOG_INFO, "Trying to sync");
*block = oldblock;
ts->retries++;
goto send_ack; /* rexmit */
}
} else {
tftp_log(LOG_WARNING,
"Expected DATA block, got %s block",
packettype(rp->th_opcode));
}
}
if (n_data > 0) {
writesize = write_file(rp->th_data, n_data);
ts->amount += writesize;
if (writesize <= 0) {
tftp_log(LOG_ERR,
"write_file returned %d", writesize);
if (writesize < 0)
send_error(peer, errno + 100);
else
send_error(peer, ENOSPACE);
goto abort;
}
}
send_ack:
for (i = 0; ; i++) {
n_ack = send_ack(peer, *block);
if (n_ack > 0) {
if (i == maxtimeouts) {
tftp_log(LOG_ERR,
"Cannot send ACK packet #%d, "
"giving up", *block);
return;
}
tftp_log(LOG_ERR,
"Cannot send ACK packet #%d, trying again",
*block);
continue;
}
break;
}
gettimeofday(&(ts->tstop), NULL);
} while (n_data == segsize);
/* Don't do late packet management for the client implementation */
if (acting_as_client)
return;
for (i = 0; ; i++) {
n_data = receive_packet(peer, (char *)rp, pktsize,
NULL, timeoutpacket);
if (n_data <= 0)
break;
if (n_data > 0 &&
rp->th_opcode == DATA && /* and got a data block */
*block == rp->th_block) /* then my last ack was lost */
send_ack(peer, *block); /* resend final ack */
}
abort:
return;
}