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// Copyright (C) 2013-2022 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 <asiolink/io_address.h>
#include <dhcp/dhcp6.h>
#include <dhcp/libdhcp++.h>
#include <dhcp/option6_iaprefix.h>
#include <dhcp/option_space.h>
#include <exceptions/exceptions.h>
#include <util/io_utilities.h>
#include <sstream>
#include <stdint.h>
#include <arpa/inet.h>
using namespace std;
using namespace isc::asiolink;
using namespace isc::util;
namespace isc {
namespace dhcp {
Option6IAPrefix::Option6IAPrefix(uint16_t type, const isc::asiolink::IOAddress& prefix,
uint8_t prefix_len, uint32_t pref, uint32_t valid)
:Option6IAAddr(type, prefix, pref, valid), prefix_len_(prefix_len) {
setEncapsulatedSpace(DHCP6_OPTION_SPACE);
// Option6IAAddr will check if prefix is IPv6 and will throw if it is not
if (prefix_len > 128) {
isc_throw(BadValue, static_cast<unsigned>(prefix_len)
<< " is not a valid prefix length. "
<< "Allowed range is 0..128");
}
}
Option6IAPrefix::Option6IAPrefix(uint32_t type, OptionBuffer::const_iterator begin,
OptionBuffer::const_iterator end)
:Option6IAAddr(type, begin, end) {
setEncapsulatedSpace(DHCP6_OPTION_SPACE);
unpack(begin, end);
}
OptionPtr
Option6IAPrefix::clone() const {
return (cloneInternal<Option6IAPrefix>());
}
void Option6IAPrefix::pack(isc::util::OutputBuffer& buf, bool) const {
if (!addr_.isV6()) {
isc_throw(isc::BadValue, addr_ << " is not an IPv6 address");
}
buf.writeUint16(type_);
// len() returns complete option length. len field contains
// length without 4-byte option header
buf.writeUint16(len() - getHeaderLen());
buf.writeUint32(preferred_);
buf.writeUint32(valid_);
buf.writeUint8(prefix_len_);
buf.writeData(&addr_.toBytes()[0], isc::asiolink::V6ADDRESS_LEN);
// store encapsulated options (the only defined so far is PD_EXCLUDE)
packOptions(buf);
}
void Option6IAPrefix::unpack(OptionBuffer::const_iterator begin,
OptionBuffer::const_iterator end) {
if ( distance(begin, end) < OPTION6_IAPREFIX_LEN) {
isc_throw(OutOfRange, "Option " << type_ << " truncated");
}
preferred_ = readUint32(&(*begin), distance(begin, end));
begin += sizeof(uint32_t);
valid_ = readUint32(&(*begin), distance(begin, end));
begin += sizeof(uint32_t);
prefix_len_ = *begin;
begin += sizeof(uint8_t);
// 16 bytes: IPv6 address
OptionBuffer address_with_mask;
mask(begin, begin + V6ADDRESS_LEN, prefix_len_, address_with_mask);
addr_ = IOAddress::fromBytes(AF_INET6, &(*address_with_mask.begin()));
begin += V6ADDRESS_LEN;
// unpack encapsulated options (the only defined so far is PD_EXCLUDE)
unpackOptions(OptionBuffer(begin, end));
}
std::string Option6IAPrefix::toText(int indent) const {
std::stringstream output;
output << headerToText(indent, "IAPREFIX") << ": "
<< "prefix=" << addr_ << "/" << static_cast<int>(prefix_len_)
<< ", preferred-lft=" << preferred_
<< ", valid-lft=" << valid_;
output << suboptionsToText(indent + 2);
return (output.str());
}
uint16_t Option6IAPrefix::len() const {
uint16_t length = OPTION6_HDR_LEN + OPTION6_IAPREFIX_LEN;
// length of all suboptions
for (OptionCollection::const_iterator it = options_.begin();
it != options_.end(); ++it) {
length += (*it).second->len();
}
return (length);
}
void
Option6IAPrefix::mask(OptionBuffer::const_iterator begin,
OptionBuffer::const_iterator end,
const uint8_t len,
OptionBuffer& output_address) const {
output_address.resize(16, 0);
if (len >= 128) {
std::copy(begin, end, output_address.begin());
} else if (len > 0) {
// All the bits that represent whole octets of the prefix are copied with
// no change.
std::copy(begin, begin + static_cast<uint8_t>(len/8), output_address.begin());
// The remaining significant bits of the last octet have to be left unchanged,
// but the remaining bits of this octet must be set to zero. The number of
// significant bits is calculated as a reminder from the division of the
// prefix length by 8 (by size of the octet). The number of bits to be set
// to zero is therefore calculated as: 8 - (len % 8).
// Next, the mask is created by shifting the 0xFF by the number of bits
// to be set to 0. By performing logical AND of this mask with the original
// value of the last octet we get the final value for the new octet.
output_address[len/8] = (*(begin + len/8) & (0xFF << (8 - (len % 8))));
}
}
} // end of namespace isc::dhcp
} // end of namespace isc
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