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diff --git a/src/lib/util/io.h b/src/lib/util/io.h
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+++ b/src/lib/util/io.h
@@ -0,0 +1,113 @@
+// Copyright (C) 2011-2024 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/.
+
+#ifndef KEA_UTIL_IO_H
+#define KEA_UTIL_IO_H
+
+#include <algorithm>
+#include <cstddef>
+#include <cstdint>
+
+namespace isc {
+namespace util {
+
+/// \brief Read an unsigned integer from given buffer.
+///
+/// \tparam uint_t Data type of the unsigned integer.
+/// \param buffer Data buffer at least two bytes long of which the first bytes are assumed to
+///        represent an unsigned integer in network-byte order.
+/// \param length Length of the data buffer.
+///
+/// \return Value of the integer.
+template <typename uint_t>
+uint_t
+readUint(void const* const buffer, size_t const length) {
+    constexpr size_t size(sizeof(uint_t));
+    if (length < size) {
+        isc_throw(OutOfRange, "Expected buffer to be long enough to read a "
+                                  << size << "-byte integer, but got " << length << " byte"
+                                  << (length == 1 ? "" : "s") << " instead");
+    }
+
+    uint8_t const* const byte_buffer(static_cast<uint8_t const*>(buffer));
+    uint_t result(0);
+
+    for (size_t i = 0; i < size; ++i) {
+        result |= (static_cast<uint_t>(byte_buffer[i])) << (8 * (size - (i + 1)));
+    }
+
+    return (result);
+}
+
+/// \brief Write the given unsigned integer to the given buffer.
+///
+/// \tparam uint_t Data type of the unsigned integer.
+/// \param value Value to convert.
+/// \param buffer Data buffer at least two bytes long into which the unsigned integer value is
+///        written in network-byte order.
+/// \param length Length of the data buffer.
+///
+/// \return pointer to the next byte after stored value
+template <typename uint_t>
+uint8_t*
+writeUint(uint_t const value, void* const buffer, size_t const length) {
+    constexpr size_t size(sizeof(uint_t));
+    if (length < size) {
+        isc_throw(OutOfRange, "Expected buffer to be long enough to write a "
+                                  << size << "-byte integer, but got " << length << " byte"
+                                  << (length == 1 ? "" : "s") << " instead");
+    }
+
+    uint8_t* byte_buffer(static_cast<uint8_t*>(buffer));
+
+    for (size_t i = 0; i < size; ++i) {
+        uint8_t const shift_by(8 * (size - (i + 1)));
+        byte_buffer[i] = uint8_t((value & (uint_t(0xff) << shift_by)) >> shift_by);
+    }
+
+    return (byte_buffer + size);
+}
+
+/// \brief uint16_t wrapper over readUint.
+inline uint16_t
+readUint16(void const* const buffer, size_t const length) {
+    return (readUint<uint16_t>(buffer, length));
+}
+
+/// \brief uint32_t wrapper over readUint.
+inline uint32_t
+readUint32(void const* const buffer, size_t const length) {
+    return (readUint<uint32_t>(buffer, length));
+}
+
+/// \brief uint16_t wrapper over readUint.
+inline uint64_t
+readUint64(void const* const buffer, size_t const length) {
+    return (readUint<uint64_t>(buffer, length));
+}
+
+/// \brief uint16_t wrapper over writeUint.
+inline uint8_t*
+writeUint16(uint16_t const value, void* const buffer, size_t const length) {
+    return (writeUint(value, buffer, length));
+}
+
+/// \brief uint32_t wrapper over writeUint.
+inline uint8_t*
+writeUint32(uint32_t const value, void* const buffer, size_t const length) {
+    return (writeUint(value, buffer, length));
+}
+
+/// \brief uint64_t wrapper over writeUint.
+inline uint8_t*
+writeUint64(uint64_t const value, void* const buffer, size_t const length) {
+    return (writeUint(value, buffer, length));
+}
+
+}  // namespace util
+}  // namespace isc
+
+#endif  // KEA_UTIL_IO_H