freebsd-skq/libexec/tftpd/tftp-options.c
jhb 0c8fe5d83d Add support for the TFTP windowsize option described in RFC 7440.
The windowsize option permits multiple blocks to be transmitted
before the receiver sends an ACK improving throughput for larger
files.

Reviewed by:	asomers
MFC after:	2 weeks
Sponsored by:	DARPA
Differential Revision:	https://reviews.freebsd.org/D23836
2020-03-02 22:19:30 +00:00

427 lines
10 KiB
C

/*-
* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
*
* 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/socket.h>
#include <sys/types.h>
#include <sys/sysctl.h>
#include <sys/stat.h>
#include <netinet/in.h>
#include <arpa/tftp.h>
#include <ctype.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <syslog.h>
#include "tftp-utils.h"
#include "tftp-io.h"
#include "tftp-options.h"
/*
* Option handlers
*/
struct options options[] = {
{ "tsize", NULL, NULL, NULL /* option_tsize */, 1 },
{ "timeout", NULL, NULL, option_timeout, 1 },
{ "blksize", NULL, NULL, option_blksize, 1 },
{ "blksize2", NULL, NULL, option_blksize2, 0 },
{ "rollover", NULL, NULL, option_rollover, 0 },
{ "windowsize", NULL, NULL, option_windowsize, 1 },
{ NULL, NULL, NULL, NULL, 0 }
};
/* By default allow them */
int options_rfc_enabled = 1;
int options_extra_enabled = 1;
/*
* Rules for the option handlers:
* - If there is no o_request, there will be no processing.
*
* For servers
* - Logging is done as warnings.
* - The handler exit()s if there is a serious problem with the
* values submitted in the option.
*
* For clients
* - Logging is done as errors. After all, the server shouldn't
* return rubbish.
* - The handler returns if there is a serious problem with the
* values submitted in the option.
* - Sending the EBADOP packets is done by the handler.
*/
int
option_tsize(int peer __unused, struct tftphdr *tp __unused, int mode,
struct stat *stbuf)
{
if (options[OPT_TSIZE].o_request == NULL)
return (0);
if (mode == RRQ)
asprintf(&options[OPT_TSIZE].o_reply,
"%ju", stbuf->st_size);
else
/* XXX Allows writes of all sizes. */
options[OPT_TSIZE].o_reply =
strdup(options[OPT_TSIZE].o_request);
return (0);
}
int
option_timeout(int peer)
{
int to;
if (options[OPT_TIMEOUT].o_request == NULL)
return (0);
to = atoi(options[OPT_TIMEOUT].o_request);
if (to < TIMEOUT_MIN || to > TIMEOUT_MAX) {
tftp_log(acting_as_client ? LOG_ERR : LOG_WARNING,
"Received bad value for timeout. "
"Should be between %d and %d, received %d",
TIMEOUT_MIN, TIMEOUT_MAX, to);
send_error(peer, EBADOP);
if (acting_as_client)
return (1);
exit(1);
} else {
timeoutpacket = to;
options[OPT_TIMEOUT].o_reply =
strdup(options[OPT_TIMEOUT].o_request);
}
settimeouts(timeoutpacket, timeoutnetwork, maxtimeouts);
if (debug&DEBUG_OPTIONS)
tftp_log(LOG_DEBUG, "Setting timeout to '%s'",
options[OPT_TIMEOUT].o_reply);
return (0);
}
int
option_rollover(int peer)
{
if (options[OPT_ROLLOVER].o_request == NULL)
return (0);
if (strcmp(options[OPT_ROLLOVER].o_request, "0") != 0
&& strcmp(options[OPT_ROLLOVER].o_request, "1") != 0) {
tftp_log(acting_as_client ? LOG_ERR : LOG_WARNING,
"Bad value for rollover, "
"should be either 0 or 1, received '%s', "
"ignoring request",
options[OPT_ROLLOVER].o_request);
if (acting_as_client) {
send_error(peer, EBADOP);
return (1);
}
return (0);
}
options[OPT_ROLLOVER].o_reply =
strdup(options[OPT_ROLLOVER].o_request);
if (debug&DEBUG_OPTIONS)
tftp_log(LOG_DEBUG, "Setting rollover to '%s'",
options[OPT_ROLLOVER].o_reply);
return (0);
}
int
option_blksize(int peer)
{
u_long maxdgram;
size_t len;
if (options[OPT_BLKSIZE].o_request == NULL)
return (0);
/* maximum size of an UDP packet according to the system */
len = sizeof(maxdgram);
if (sysctlbyname("net.inet.udp.maxdgram",
&maxdgram, &len, NULL, 0) < 0) {
tftp_log(LOG_ERR, "sysctl: net.inet.udp.maxdgram");
return (acting_as_client ? 1 : 0);
}
int size = atoi(options[OPT_BLKSIZE].o_request);
if (size < BLKSIZE_MIN || size > BLKSIZE_MAX) {
if (acting_as_client) {
tftp_log(LOG_ERR,
"Invalid blocksize (%d bytes), aborting",
size);
send_error(peer, EBADOP);
return (1);
} else {
tftp_log(LOG_WARNING,
"Invalid blocksize (%d bytes), ignoring request",
size);
return (0);
}
}
if (size > (int)maxdgram) {
if (acting_as_client) {
tftp_log(LOG_ERR,
"Invalid blocksize (%d bytes), "
"net.inet.udp.maxdgram sysctl limits it to "
"%ld bytes.\n", size, maxdgram);
send_error(peer, EBADOP);
return (1);
} else {
tftp_log(LOG_WARNING,
"Invalid blocksize (%d bytes), "
"net.inet.udp.maxdgram sysctl limits it to "
"%ld bytes.\n", size, maxdgram);
size = maxdgram;
/* No reason to return */
}
}
asprintf(&options[OPT_BLKSIZE].o_reply, "%d", size);
segsize = size;
pktsize = size + 4;
if (debug&DEBUG_OPTIONS)
tftp_log(LOG_DEBUG, "Setting blksize to '%s'",
options[OPT_BLKSIZE].o_reply);
return (0);
}
int
option_blksize2(int peer __unused)
{
u_long maxdgram;
int size, i;
size_t len;
int sizes[] = {
8, 16, 32, 64, 128, 256, 512, 1024,
2048, 4096, 8192, 16384, 32768, 0
};
if (options[OPT_BLKSIZE2].o_request == NULL)
return (0);
/* maximum size of an UDP packet according to the system */
len = sizeof(maxdgram);
if (sysctlbyname("net.inet.udp.maxdgram",
&maxdgram, &len, NULL, 0) < 0) {
tftp_log(LOG_ERR, "sysctl: net.inet.udp.maxdgram");
return (acting_as_client ? 1 : 0);
}
size = atoi(options[OPT_BLKSIZE2].o_request);
for (i = 0; sizes[i] != 0; i++) {
if (size == sizes[i]) break;
}
if (sizes[i] == 0) {
tftp_log(LOG_INFO,
"Invalid blocksize2 (%d bytes), ignoring request", size);
return (acting_as_client ? 1 : 0);
}
if (size > (int)maxdgram) {
for (i = 0; sizes[i+1] != 0; i++) {
if ((int)maxdgram < sizes[i+1]) break;
}
tftp_log(LOG_INFO,
"Invalid blocksize2 (%d bytes), net.inet.udp.maxdgram "
"sysctl limits it to %ld bytes.\n", size, maxdgram);
size = sizes[i];
/* No need to return */
}
asprintf(&options[OPT_BLKSIZE2].o_reply, "%d", size);
segsize = size;
pktsize = size + 4;
if (debug&DEBUG_OPTIONS)
tftp_log(LOG_DEBUG, "Setting blksize2 to '%s'",
options[OPT_BLKSIZE2].o_reply);
return (0);
}
int
option_windowsize(int peer)
{
int size;
if (options[OPT_WINDOWSIZE].o_request == NULL)
return (0);
size = atoi(options[OPT_WINDOWSIZE].o_request);
if (size < WINDOWSIZE_MIN || size > WINDOWSIZE_MAX) {
if (acting_as_client) {
tftp_log(LOG_ERR,
"Invalid windowsize (%d blocks), aborting",
size);
send_error(peer, EBADOP);
return (1);
} else {
tftp_log(LOG_WARNING,
"Invalid windowsize (%d blocks), ignoring request",
size);
return (0);
}
}
/* XXX: Should force a windowsize of 1 for non-seekable files. */
asprintf(&options[OPT_WINDOWSIZE].o_reply, "%d", size);
windowsize = size;
if (debug&DEBUG_OPTIONS)
tftp_log(LOG_DEBUG, "Setting windowsize to '%s'",
options[OPT_WINDOWSIZE].o_reply);
return (0);
}
/*
* Append the available options to the header
*/
uint16_t
make_options(int peer __unused, char *buffer, uint16_t size) {
int i;
char *value;
const char *option;
uint16_t length;
uint16_t returnsize = 0;
if (!options_rfc_enabled) return (0);
for (i = 0; options[i].o_type != NULL; i++) {
if (options[i].rfc == 0 && !options_extra_enabled)
continue;
option = options[i].o_type;
if (acting_as_client)
value = options[i].o_request;
else
value = options[i].o_reply;
if (value == NULL)
continue;
length = strlen(value) + strlen(option) + 2;
if (size <= length) {
tftp_log(LOG_ERR,
"Running out of option space for "
"option '%s' with value '%s': "
"needed %d bytes, got %d bytes",
option, value, size, length);
continue;
}
sprintf(buffer, "%s%c%s%c", option, '\000', value, '\000');
size -= length;
buffer += length;
returnsize += length;
}
return (returnsize);
}
/*
* Parse the received options in the header
*/
int
parse_options(int peer, char *buffer, uint16_t size)
{
int i, options_failed;
char *c, *cp, *option, *value;
if (!options_rfc_enabled) return (0);
/* Parse the options */
cp = buffer;
options_failed = 0;
while (size > 0) {
option = cp;
i = get_field(peer, cp, size);
cp += i;
value = cp;
i = get_field(peer, cp, size);
cp += i;
/* We are at the end */
if (*option == '\0') break;
if (debug&DEBUG_OPTIONS)
tftp_log(LOG_DEBUG,
"option: '%s' value: '%s'", option, value);
for (c = option; *c; c++)
if (isupper(*c))
*c = tolower(*c);
for (i = 0; options[i].o_type != NULL; i++) {
if (strcmp(option, options[i].o_type) == 0) {
if (!acting_as_client)
options[i].o_request = value;
if (!options_extra_enabled && !options[i].rfc) {
tftp_log(LOG_INFO,
"Option '%s' with value '%s' found "
"but it is not an RFC option",
option, value);
continue;
}
if (options[i].o_handler)
options_failed +=
(options[i].o_handler)(peer);
break;
}
}
if (options[i].o_type == NULL)
tftp_log(LOG_WARNING,
"Unknown option: '%s'", option);
size -= strlen(option) + strlen(value) + 2;
}
return (options_failed);
}
/*
* Set some default values in the options
*/
void
init_options(void)
{
options[OPT_ROLLOVER].o_request = strdup("0");
}