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tftpd_options.cpp
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tftpd_options.cpp
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/*
* Copyright (c) 1983 Regents of the University of California.
* Copyright (c) 1999-2009 H. Peter Anvin
* Copyright (c) 2011-2014 Intel Corporation; author: H. Peter Anvin
* 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 by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 THE REGENTS 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 "tftp/tftpsubs.h"
#include <arpa/inet.h>
#include <cassert>
#include <cerrno>
#include <cinttypes> // strtoumax used
#include <cstring> // strcasecmp, memcpy used
#include <string>
#include <syslog.h>
namespace tftpd {
constexpr uintmax_t min_blksize_rfc{8}; // TBD: after RFC2348! CK
constexpr uintmax_t default_blksize{SEGSIZE};
constexpr uintmax_t max_blksize{MAXSEGSIZE};
// unused constexpr uintmax_t max_windowsize{64};
constexpr uintmax_t max_timeout{255}; // seconds
constexpr uintmax_t MS_1K{1000}; // default timeout
// XXX static uint16_t rollover_val = 0;
// XXX static uintmax_t windowsize = 1;
static constexpr bool tsize_ok{true}; // only octet mode supported!
uintmax_t g_timeout = MS_1K; // NOTE: 1 s as ms! CK
uintmax_t g_segsize{default_blksize};
off_t g_tsize{0};
static bool set_blksize(uintmax_t *vp);
static bool set_blksize2(uintmax_t *vp);
static bool set_tsize(uintmax_t *vp);
static bool set_timeout(uintmax_t *vp);
static bool set_utimeout(uintmax_t *vp);
// XXX static bool set_rollover(uintmax_t *vp);
// XXX static bool set_windowsize(uintmax_t *vp);
struct option
{
const char *o_opt;
bool (*o_fnc)(uintmax_t *);
};
static const struct option options[] = {{"blksize", set_blksize},
{"blksize2", set_blksize2},
{"tsize", set_tsize},
{"timeout", set_timeout},
{"utimeout", set_utimeout},
// TBD: {"rollover", set_rollover},
// TBD: not yet! CK {"windowsize", set_windowsize},
{nullptr, nullptr}};
static bool blksize_set{false};
/*
* Set a non-standard block size (c.f. RFC2348)
*/
static bool set_blksize(uintmax_t *vp)
{
uintmax_t sz = *vp;
if (blksize_set) {
return false;
}
if (sz < min_blksize_rfc) {
return false;
}
if (sz > max_blksize) {
sz = max_blksize;
}
*vp = g_segsize = sz;
blksize_set = true;
return true;
}
/*
* Set a power-of-two block size (nonstandard)
*/
static bool set_blksize2(uintmax_t *vp)
{
uintmax_t sz = *vp;
if (blksize_set) {
return false;
}
if (sz < min_blksize_rfc) {
return false;
}
if (sz > max_blksize) {
sz = max_blksize;
} else {
/* Convert to a power of two */
if ((sz & (sz - 1)) != 0) {
uintmax_t sz1 = 1;
/* Not a power of two - need to convert */
while ((sz >>= 1) != 0) {
sz1 <<= 1;
}
sz = sz1;
}
}
*vp = g_segsize = sz;
blksize_set = true;
return true;
}
/***
* Set the block number rollover value
static bool set_rollover(uintmax_t *vp)
{
uintmax_t ro = *vp;
if (ro > UINT16_MAX) {
return false;
}
rollover_val = (uint16_t)ro;
return true;
}
***/
/*
* Return a file size (c.f. RFC2349)
* For netascii mode, we don't know the size ahead of time;
* so reject the option.
*/
static bool set_tsize(uintmax_t *vp)
{
uintmax_t sz = *vp;
if (!tsize_ok) {
return false; // netascii
}
if (sz == 0) {
sz = g_tsize; // only useful for RRQ
} else {
g_tsize = sz; // in case of WRQ
}
*vp = sz;
return true;
}
/*
* Set the timeout (c.f. RFC2349). This is supposed
* to be the (default) retransmission timeout, but being an
* integer in seconds it seems a bit limited.
*/
static bool set_timeout(uintmax_t *vp)
{
uintmax_t const to = *vp;
if (to < 1 || to > max_timeout) {
return false;
}
g_timeout = to * MS_1K;
return true;
}
/*
* Similar, but in microseconds. We allow down to 10 ms.
*/
static bool set_utimeout(uintmax_t *vp)
{
uintmax_t const to = *vp;
if (to < MS_1K || to > (max_timeout * MS_1K * MS_1K)) {
return false;
}
g_timeout = to / MS_1K;
return true;
}
/***
* Set window size (c.f. RFC7440)
static bool set_windowsize(uintmax_t *vp)
{
if (*vp < 1 || *vp > max_windowsize) {
return false;
}
windowsize = *vp;
return true;
}
***/
/* Global option-parsing variables initialization */
void init_opt()
{
blksize_set = false;
g_segsize = default_blksize;
g_timeout = MS_1K;
g_tsize = 0;
}
/*
* Parse RFC2347 style options; we limit the arguments to positive
* integers which matches all our current options.
*/
void do_opt(const char *opt, const char *val, char **ackbuf_ptr)
{
const struct option *po = nullptr;
char *p = *ackbuf_ptr;
assert(ackbuf_ptr != nullptr);
assert(opt != nullptr);
assert(val != nullptr);
if (*opt == 0 || *val == 0) {
return;
}
// NOLINTNEXTLINE(cppcoreguidelines-pro-type-vararg)
syslog(LOG_NOTICE, "tftpd: %s:%s\n", opt, val);
errno = 0;
char *vend = nullptr;
uintmax_t v = strtoumax(val, &vend, 10); // TODO: or std::strtoul! CK
if (*vend != 0 || errno == ERANGE) {
// NOLINTNEXTLINE(cppcoreguidelines-pro-type-vararg)
syslog(LOG_ERR, "tftpd: Invallid option value (%s:%s)\n", opt, val);
return;
}
for (po = options; po->o_opt != nullptr; po++) {
if (strcasecmp(po->o_opt, opt) == 0) { // XXX C-style compare
if (po->o_fnc(&v)) { // found and the option is valid
size_t const optlen = strlen(opt);
std::string const ret_value = std::to_string(v);
size_t const retlen = ret_value.size();
memcpy(p, opt, optlen + 1);
p += optlen + 1;
memcpy(p, ret_value.c_str(), retlen + 1);
p += retlen + 1;
} else {
// NOLINTNEXTLINE(cppcoreguidelines-pro-type-vararg)
syslog(LOG_ERR, "tftpd: Unsupported option(%s:%s)\n", opt, val);
}
break;
}
}
*ackbuf_ptr = p;
}
} // namespace tftpd