1 files changed, 148 insertions, 0 deletions
diff --git a/src/lib/dhcp/option6_iaprefix.cc b/src/lib/dhcp/option6_iaprefix.cc
new file mode 100644
index 0000000..fcca8b0
--- /dev/null
+++ b/src/lib/dhcp/option6_iaprefix.cc
@@ -0,0 +1,148 @@
+// 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