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// Copyright (C) 2010-2015 Internet Systems Consortium, Inc. ("ISC")
//
// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this
// file, You can obtain one at http://mozilla.org/MPL/2.0/.
#include <config.h>
#include <stdint.h>
#include <sstream>
#include <ostream>
#include <util/buffer.h>
#include <dns/messagerenderer.h>
#include <dns/rrttl.h>
#include <boost/lexical_cast.hpp>
#include <algorithm>
#include <cctype>
using namespace std;
using namespace isc::dns;
using namespace isc::util;
namespace {
// We wrap the C isalpha, because it seems to be overloaded with something.
// Then the find_if doesn't work.
bool
myIsalpha(char c) {
return (isalpha(c) != 0);
}
// The conversion of units to their size
struct Unit {
char unit;
uint32_t multiply;
uint32_t max_allowed;
};
Unit units[] = {
{ 'S', 1, 0xffffffff / 1 },
{ 'M', 60, 0xffffffff / 60 },
{ 'H', 60 * 60, 0xffffffff / (60 * 60) },
{ 'D', 24 * 60 * 60, 0xffffffff / (24 * 60 * 60) },
{ 'W', 7 * 24 * 60 * 60, 0xffffffff / (7 * 24 * 60 * 60) }
};
}
namespace isc {
namespace dns {
namespace {
bool
parseTTLString(const string& ttlstr, uint32_t& ttlval, string* error_txt) {
if (ttlstr.empty()) {
if (error_txt != NULL) {
*error_txt = "Empty TTL string";
}
return (false);
}
// We use a larger data type to handle negative number cases.
uint64_t val = 0;
const string::const_iterator end = ttlstr.end();
string::const_iterator pos = ttlstr.begin();
try {
// When we detect we have some units
bool units_mode = false;
while (pos != end) {
// Find the first unit, if there's any.
const string::const_iterator unit = find_if(pos, end, myIsalpha);
// No unit
if (unit == end) {
if (units_mode) {
// We had some units before. The last one is missing unit.
if (error_txt != NULL) {
*error_txt = "Missing the last unit: " + ttlstr;
}
return (false);
} else {
// Case without any units at all. Just convert and store
// it.
val = boost::lexical_cast<uint64_t>(ttlstr);
break;
}
}
// There's a unit now.
units_mode = true;
// Find the unit and get the size.
uint32_t multiply = 1; // initialize to silence compiler warnings
uint32_t max_allowed = 0xffffffff;
bool found = false;
for (size_t i = 0; i < sizeof(units) / sizeof(*units); ++i) {
if (toupper(*unit) == units[i].unit) {
found = true;
multiply = units[i].multiply;
max_allowed = units[i].max_allowed;
break;
}
}
if (!found) {
if (error_txt != NULL) {
*error_txt = "Unknown unit used: " +
boost::lexical_cast<string>(*unit) + " in: " + ttlstr;
}
return (false);
}
// Now extract the number.
if (unit == pos) {
if (error_txt != NULL) {
*error_txt = "Missing number in TTL: " + ttlstr;
}
return (false);
}
const uint64_t value =
boost::lexical_cast<uint64_t>(string(pos, unit));
if (value > max_allowed) {
if (error_txt != NULL) {
*error_txt = "Part of TTL out of range: " + ttlstr;
}
return (false);
}
// seconds cannot be out of range at this point.
const uint64_t seconds = value * multiply;
assert(seconds <= 0xffffffff);
// Add what we found
val += seconds;
// Check the partial value is still in range (the value can only
// grow, so if we get out of range now, it won't get better, so
// there's no need to continue).
if (val < seconds || val > 0xffffffff) {
if (error_txt != NULL) {
*error_txt = "Part of TTL out of range: " + ttlstr;
}
return (false);
}
// Move to after the unit.
pos = unit + 1;
}
} catch (const boost::bad_lexical_cast&) {
if (error_txt != NULL) {
*error_txt = "invalid TTL: " + ttlstr;
}
return (false);
}
if (val <= 0xffffffff) {
ttlval = val;
} else {
// This could be due to negative numbers in input, etc.
if (error_txt != NULL) {
*error_txt = "TTL out of range: " + ttlstr;
}
return (false);
}
return (true);
}
}
RRTTL::RRTTL(const std::string& ttlstr) {
string error_txt;
if (!parseTTLString(ttlstr, ttlval_, &error_txt)) {
isc_throw(InvalidRRTTL, error_txt);
}
}
RRTTL*
RRTTL::createFromText(const string& ttlstr) {
uint32_t ttlval;
if (parseTTLString(ttlstr, ttlval, NULL)) {
return (new RRTTL(ttlval));
}
return (NULL);
}
RRTTL::RRTTL(InputBuffer& buffer) {
if (buffer.getLength() - buffer.getPosition() < sizeof(uint32_t)) {
isc_throw(IncompleteRRTTL, "incomplete wire-format TTL value");
}
ttlval_ = buffer.readUint32();
}
const string
RRTTL::toText() const {
ostringstream oss;
oss << ttlval_;
return (oss.str());
}
void
RRTTL::toWire(OutputBuffer& buffer) const {
buffer.writeUint32(ttlval_);
}
void
RRTTL::toWire(AbstractMessageRenderer& renderer) const {
renderer.writeUint32(ttlval_);
}
ostream&
operator<<(ostream& os, const RRTTL& rrttl) {
os << rrttl.toText();
return (os);
}
}
}
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