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// Copyright (C) 2011-2015 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 <exceptions/exceptions.h>
#include <dns/exceptions.h>
#include <dns/rdata.h>
#include <dns/rrtype.h>
#include <cassert>
#include <sstream>
#include <vector>
#include <cstring>
#include <stdint.h>
using namespace std;
namespace isc {
namespace dns {
namespace rdata {
namespace generic {
namespace detail {
namespace nsec {
void
checkRRTypeBitmaps(const char* const rrtype_name,
const vector<uint8_t>& typebits)
{
bool first = true;
unsigned int lastblock = 0;
const size_t total_len = typebits.size();
size_t i = 0;
while (i < total_len) {
if (i + 2 > total_len) {
isc_throw(DNSMessageFORMERR, rrtype_name <<
" RDATA from wire: incomplete bit map field");
}
const unsigned int block = typebits[i];
const size_t len = typebits[i + 1];
// Check that bitmap window blocks are in the correct order.
if (!first && block <= lastblock) {
isc_throw(DNSMessageFORMERR, rrtype_name <<
" RDATA from wire: Disordered window blocks found: "
<< lastblock << " then " << block);
}
// Check for legal length
if (len < 1 || len > 32) {
isc_throw(DNSMessageFORMERR, rrtype_name <<
" RDATA from wire: Invalid bitmap length: " << len);
}
// Check for overflow.
i += 2;
if (i + len > total_len) {
isc_throw(DNSMessageFORMERR, rrtype_name <<
" RDATA from wire: bitmap length too large: " << len);
}
// The last octet of the bitmap must be non zero.
if (typebits[i + len - 1] == 0) {
isc_throw(DNSMessageFORMERR, rrtype_name <<
" RDATA from wire: bitmap ending an all-zero byte");
}
i += len;
lastblock = block;
first = false;
}
}
void
buildBitmapsFromLexer(const char* const rrtype_name,
MasterLexer& lexer, vector<uint8_t>& typebits,
bool allow_empty)
{
uint8_t bitmap[8 * 1024]; // 64k bits
memset(bitmap, 0, sizeof(bitmap));
bool have_rrtypes = false;
std::string type_str;
while (true) {
const MasterToken& token =
lexer.getNextToken(MasterToken::STRING, true);
if ((token.getType() == MasterToken::END_OF_FILE) ||
(token.getType() == MasterToken::END_OF_LINE)) {
break;
}
// token is now assured to be of type STRING.
have_rrtypes = true;
token.getString(type_str);
try {
const int code = RRType(type_str).getCode();
bitmap[code / 8] |= (0x80 >> (code % 8));
} catch (const InvalidRRType&) {
isc_throw(InvalidRdataText, "Invalid RRtype in "
<< rrtype_name << " bitmap: " << type_str);
}
}
lexer.ungetToken();
if (!have_rrtypes) {
if (allow_empty) {
return;
}
isc_throw(InvalidRdataText,
rrtype_name <<
" record does not end with RR type mnemonic");
}
for (int window = 0; window < 256; ++window) {
int octet;
for (octet = 31; octet >= 0; octet--) {
if (bitmap[window * 32 + octet] != 0) {
break;
}
}
if (octet < 0) {
continue;
}
typebits.push_back(window);
typebits.push_back(octet + 1);
for (int i = 0; i <= octet; ++i) {
typebits.push_back(bitmap[window * 32 + i]);
}
}
}
void
bitmapsToText(const vector<uint8_t>& typebits, ostringstream& oss) {
// In the following loop we use string::at() rather than operator[].
// Since the index calculation is a bit complicated, it will be safer
// and easier to find a bug (if any). Note that this conversion method
// is generally not expected to be very efficient, so the slight overhead
// of at() should be acceptable.
const size_t typebits_len = typebits.size();
size_t len = 0;
for (size_t i = 0; i < typebits_len; i += len) {
assert(i + 2 <= typebits.size());
const unsigned int block = typebits.at(i);
len = typebits.at(i + 1);
assert(len > 0 && len <= 32);
i += 2;
for (size_t j = 0; j < len; ++j) {
if (typebits.at(i + j) == 0) {
continue;
}
for (size_t k = 0; k < 8; ++k) {
if ((typebits.at(i + j) & (0x80 >> k)) == 0) {
continue;
}
const unsigned int t = block * 256 + j * 8 + k;
assert(t < 65536);
oss << " " << RRType(t);
}
}
}
}
}
}
}
}
}
}
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