diff options
Diffstat (limited to 'src/main/kotlin/net')
| -rw-r--r-- | src/main/kotlin/net/InMessage.kt | 167 | ||||
| -rw-r--r-- | src/main/kotlin/net/OutMessage.kt | 127 | ||||
| -rw-r--r-- | src/main/kotlin/net/TransportLayer.kt | 59 | ||||
| -rw-r--r-- | src/main/kotlin/net/TransportLayerJavaNet.kt | 95 |
4 files changed, 448 insertions, 0 deletions
diff --git a/src/main/kotlin/net/InMessage.kt b/src/main/kotlin/net/InMessage.kt new file mode 100644 index 0000000..771c670 --- /dev/null +++ b/src/main/kotlin/net/InMessage.kt @@ -0,0 +1,167 @@ +package net + +import NinePMessageType +import except.InvalidMessageException +import java.math.BigInteger + +/** + * An incoming 9P message. Upon instancing this class only one message is read, and it's represented in a way similar to + * that of [OutMessage]. This class is supposed to be complementary, and opposite, to [OutMessage]. + * + * @param tl The transport layer API. + * @param maxSize The maximum message size negotiated with the remote part. + * @param reqTag The required tag. + * @throws InvalidMessageException if the message that is currently being read is invalid. + */ +class InMessage(val tl: TransportLayer, maxSize: UInt, val reqTag: UShort) { + /** + * The total size of the message. + */ + val size: UInt + + /** + * The message type. + */ + val type: NinePMessageType + + /** + * The message tag. + */ + val tag: UShort + + /** + * A map of each integer field's name to its value. + */ + var fieldsInt: MutableMap<String, BigInteger> = mutableMapOf() + private set + + /** + * A map of each string field's name to its value. + */ + var fieldsStr: MutableMap<String, String> = mutableMapOf() + private set + + /** + * A map of each raw field's name to its value. + */ + var fieldsRaw: MutableMap<String, Array<UByte>> = mutableMapOf() + private set + + /** + * An ordered collection of raw bytes that still need to be interpreted as values. + */ + private var rawData: List<UByte> + + init { + size = convInteger(this.tl.receiver(), 0, 4).toInt().toUInt() + if (this.size > maxSize) { + throw InvalidMessageException("Size greater than maximum size (${this.size} > ${maxSize}).") + } + try { + this.type = NinePMessageType.fromByte(convInteger(this.tl.receiver(), 0, 1).toInt().toUByte()) + } catch (_: NoSuchElementException) { + throw InvalidMessageException("Invalid 9P message type.") + } + tag = convInteger(this.tl.receiver(), 0, 2).toInt().toUShort() + if (tag != reqTag) { + // TODO: what do we do now? + } + this.rawData = this.tl.receive((size - (4u + 1u + 2u)).toULong()).toList() + } + + /** + * Field of an incoming 9P message. An ordered collection of fields makes a schema. + * + * @param name The field's name. It's typically the same you can find in the manual pages. + * @param type The field's type. + * @param size The field's size in bytes. If the type is [Type.STRING], this parameter is ignored. + */ + data class Field(val name: String, val type: Type, val size: UInt) { + + enum class Type { + INTEGER, + STRING, + RAW + } + } + + /** + * Apply the given field to the raw data and put it in one of [fieldsInt], [fieldsStr], or [fieldsRaw]. Fields must + * be applied strictly in order, as their application is not commutative. + * + * Each time a field is applied, the initial part of raw data that coincides with that field is removed. + * + * @param field The given field. + */ + fun applyField(field: Field) { + val size: Int + when (field.type) { + Field.Type.STRING -> { + val str = convString(this.rawData.toList(), 0) + size = 2 + str.length + this.fieldsStr[field.name] = str + } + Field.Type.INTEGER -> { + size = field.size.toInt() + this.fieldsInt[field.name] = convInteger(this.rawData.toList(), 0, size) + } + Field.Type.RAW -> { + size = field.size.toInt() + this.fieldsRaw[field.name] = this.rawData.take(size).toTypedArray() + } + } + this.rawData = this.rawData.drop(size) + } + + /** + * Apply the given message schema to the raw data and fill [fieldsInt], [fieldsStr], and [fieldsRaw]. + * + * Note: This method could have been avoided by making a giant `when` block in the class constructor. However, I'd + * rather let the caller, which is usually a method that makes a request and reads its response, decide the schema. + * In this way, each method that needs to read a response of a specific type (and there is usually one method per + * response type) declares its own schema, while those which cannot be easily represented by a schema (e.g. `Rwalk`) + * are simply going to be read in a field-by-field fashion. + * + * @param schema The desired ordered collection of fields. + */ + fun applySchema(schema: Iterable<Field>) { + for (field in schema) { + applyField(field) + } + } + + companion object { + /** + * Convert an [len] bytes long unsigned integer number from raw bytes. + * + * In 9P, binary numbers (non-textual) are specified in little-endian order (least significant byte first). + * + * @param len The length of the integer number in bytes. If zero, nothing is read. + * @return the number's value. + * @throws IllegalArgumentException if either [offset] or [len] are negative. + */ + fun convInteger(bytes: Iterable<UByte>, offset: Int, len: Int): BigInteger { + val bytes = bytes.drop(offset).take(len) + var value = 0.toBigInteger() + for (i in 0..<bytes.size) { + value += bytes[i].toInt().toBigInteger().shl(i*8) + } + return value + } + + /** + * Convert a string from raw bytes. + * + * In 9P, strings are represented as a 2-byte integer (the string's size) followed by the actual UTF-8 string. The + * null terminator is forbidden in 9P messages. + * + * @return the string. + * @throws IllegalArgumentException if either [offset] is negative. + */ + fun convString(bytes: Iterable<UByte>, offset: Int): String { + val length = convInteger(bytes, 0, 2).toInt() + val bytes = bytes.drop(offset).take(length) + return String(ByteArray(bytes.size) { i -> bytes[i].toByte() }) + } + } +}
\ No newline at end of file diff --git a/src/main/kotlin/net/OutMessage.kt b/src/main/kotlin/net/OutMessage.kt new file mode 100644 index 0000000..c9ae879 --- /dev/null +++ b/src/main/kotlin/net/OutMessage.kt @@ -0,0 +1,127 @@ +package net + +import NinePMessageType +import java.math.BigInteger +import kotlin.math.pow + +/** + * An outgoing 9P message with the given type, tag, and fields. The message size is calculated automatically. + * + * Important note: the field names in [fieldValuesInt], [fieldValuesStr], and [fieldValuesRaw] (i.e. the keys of their + * maps) must be mutually exclusive and the union of these two maps' keys must result in a subset of (or a set equal to) + * [fieldNames]. Calling [write] when these conditions are not met throws an exception. + * + * @param type The 9P message type. + * @param tag The tag given to the message. + * @param fieldNames The names of the message fields, in the same order they are expected to be sent. + * @param fieldValuesInt A map of each integer field's name into its value and size in bytes. + * @param fieldValuesStr A map of each string field's name into its value. + * @param fieldValuesRaw A map of each raw field's name into its value. + * @param maxSize The maximum message size. + */ +class OutMessage(val type: NinePMessageType, val tag: UShort, val fieldNames: List<String>, val fieldValuesInt: Map<String, Pair<BigInteger, UInt>>, val fieldValuesStr: Map<String, String>, val fieldValuesRaw: Map<String, List<UByte>>, val maxSize: UInt) { + /** + * Intersection between [fieldNames] and [fieldValuesInt]. In other words: the integer fields that are going to be + * used when writing the message. + */ + private val insecInts = fieldNames.intersect(fieldValuesInt.keys) + + /** + * Intersection between [fieldNames] and [fieldValuesStr]. In other words: the string fields that are going to be + * used when writing the message. + */ + private val insecStrs = fieldNames.intersect(fieldValuesStr.keys) + + /** + * Intersection between [fieldNames] and [fieldValuesRaw]. In other words: the raw fields that are going to be used + * when writing the message. + */ + private val insecRaws = fieldNames.intersect(fieldValuesRaw.keys) + + /** + * Send the message using the given networking API. + * + * @param tl The networking API. + * @throws IllegalArgumentException if [fieldNames], [fieldValuesInt], and [fieldValuesStr] are incoherent or the + * final size of the message exceeds the negotiated value. + */ + fun write(tl: TransportLayer) { + // check that names in fieldNames exist as keys in either fieldValuesInt or fieldValuesStr but not both + require(fieldNames.size == insecInts.size + insecStrs.size + insecRaws.size) + + val totalSize = size() + if (totalSize > this.maxSize) { + throw IllegalArgumentException("Message size exceeded.") + } + writeMessageSizeTypeTag(tl, totalSize, type, tag) + for (field in fieldNames) { + tl.transmit( + if (field in insecInts) { + val valsize = fieldValuesInt[field]!! + convIntegerToBytes(valsize.first, valsize.second) + } else if (field in insecStrs) { + convStringToBytes(fieldValuesStr[field]!!) + } else { + fieldValuesRaw[field]!!.toList() + } + ) + } + } + + /** + * Write the message size and type. + * + * @param tl The networking API. + * @param size The total message size, including the 4 bytes of this parameter and the type's byte. + * @param type The 9P message type as a [NinePMessageType] constant. + * @param tag The 9P message tag. + */ + private fun writeMessageSizeTypeTag(tl: TransportLayer, size: UInt, type: NinePMessageType, tag: UShort) { + var bytes: List<UByte> = emptyList() + bytes += convIntegerToBytes(BigInteger(size.toString()), 4u) + bytes += convIntegerToBytes(BigInteger(type.value.toString()), 1u) + bytes += convIntegerToBytes(BigInteger(tag.toString()), 2u) + tl.transmit(bytes) + } + + /** + * Calculate the expected size of the message. + */ + fun size(): UInt { + return 4u + 1u + 2u + this.insecInts.sumOf { this.fieldValuesInt[it]!!.second } + this.insecStrs.sumOf { 2u + this.fieldValuesStr[it]!!.length.toUInt() } + this.insecRaws.sumOf { this.fieldValuesRaw[it]!!.size.toUInt() } + } + + companion object { + // TODO: Add size that the value is required to fit in + + /** + * Convert an integer number to its byte representation. + * + * In 9P, binary numbers (non-textual) are specified in little-endian order (least significant byte first). + * + * @param value The number's value. + * @param size The number's size in bytes. + */ + fun convIntegerToBytes(value: BigInteger, size: UInt): List<UByte> { + var bytes: List<UByte> = value.toByteArray().toList().map { x -> x.toUByte() } + bytes += List(size.toInt() - bytes.size, {0u}) // add padding for missing bytes + return bytes + } + + /** + * Write a string to the connection. + * + * In 9P, strings are represented as a 2-byte integer (the string's size) followed by the actual UTF-8 string. The + * null terminator is forbidden in 9P messages. + * + * @param value The string. + * @throws IllegalArgumentException if the value of the string's size does not fit into 2 bytes. + */ + fun convStringToBytes(value: String): List<UByte> { + require(value.length <= 2.0.pow(16.0) - 1) + var bytes = convIntegerToBytes(value.length.toBigInteger(), 2u) + bytes += value.toByteArray().toList().map { x -> x.toUByte() } + return bytes + } + } +}
\ No newline at end of file diff --git a/src/main/kotlin/net/TransportLayer.kt b/src/main/kotlin/net/TransportLayer.kt new file mode 100644 index 0000000..90dcd11 --- /dev/null +++ b/src/main/kotlin/net/TransportLayer.kt @@ -0,0 +1,59 @@ +package net + +import java.io.Closeable + +/** + * [TransportLayer] is an interface for network transport-layer operations. A class that implements these methods, once + * instantiated, establishes and manages a connection with a remote endpoint defined by an address and a port and allows + * to send and receive network messages (also called "payloads"). + * + * The address of the remote endpoint can be an IP address (v4 or v6) or a domain name, in which case it is resolved to + * an IP address right before initializing the connection. Every constructor should throw an + * [except.UnresolvableHostException] if the remote address is formatted as an actual domain name, but it cannot be + * resolved (e.g. it doesn't exist, or it contains forbidden characters). + * + * Depending on the specific given implementation, the constructor of this class might throw other exceptions (e.g. the + * [java.net.Socket] constructor in [TransportLayerJavaNet]). + */ +interface TransportLayer : Closeable { + /** + * Close the connection. + */ + abstract override fun close() + + /** + * Transmit a payload. + * + * @throws java.io.IOException if the message could not be correctly transmitted. + */ + fun transmit(payload: Iterable<UByte>) +/* + /** + * Receive a payload until a byte occurs, which marks the end of the message. The byte is discarded after being read + * and is not returned. + * + * If you know both which byte marks the end of the message and the message length, it is advised to use + * [receiveFixed] instead, which is usually more efficient. + * + * @param untilByte The byte that marks the end of the message. + * @return the received payload. + * @throws java.io.IOException if the message could not be correctly received. + */ + abstract fun receiveUntil(untilByte: UByte): Array<UByte> +*/ + /** + * Receive a payload with fixed length. If zero, nothing is read. + * + * @param length The length of the message in bytes. + * @return the received payload. + * @throws java.io.IOException if the message could not be correctly received. + */ + fun receive(length: ULong): Array<UByte> + + /** + * Gives the caller a "receiver" (i.e. an instance of Iterable) from which raw data of any length can be read. + * + * @return The receiver. + */ + fun receiver(): Iterable<UByte> +}
\ No newline at end of file diff --git a/src/main/kotlin/net/TransportLayerJavaNet.kt b/src/main/kotlin/net/TransportLayerJavaNet.kt new file mode 100644 index 0000000..3d2867a --- /dev/null +++ b/src/main/kotlin/net/TransportLayerJavaNet.kt @@ -0,0 +1,95 @@ +package net + +import nineAddressToValues +import java.io.InputStream +import java.io.OutputStream +import java.net.Socket +import kotlin.math.min + +/* +TODO: + - add TLS support +*/ + +/** + * An implementation of [TransportLayer] written using the [java.net] package. + */ +class TransportLayerJavaNet(val address: String, val port: UShort) : TransportLayer { + /** + * The connection's socket. + */ + private val socket: Socket = Socket(this.address, this.port.toInt()) + + /** + * The connection's input stream. + */ + private val inStream: InputStream = this.socket.inputStream + + /** + * The connection's output stream. + */ + private val outStream: OutputStream = this.socket.outputStream + + constructor(fullAddress: String) : this(nineAddressToValues(fullAddress).first, nineAddressToValues(fullAddress).second) + + private class InStreamIterator(val inStream: InputStream) : Iterator<UByte> { + override fun next(): UByte { + return this.inStream.readNBytes(1).first().toUByte() + } + + override fun hasNext(): Boolean { + return this.inStream.available() > 0 + } + } + + override fun close() { + if (this.socket.isClosed) { + return + } + this.socket.close() + } + + override fun transmit(payload: Iterable<UByte>) { + val payload = payload.toList() + val bytes = ByteArray(payload.size, { i -> payload[i].toByte() }) + this.outStream.write(bytes) + } + +/* + override fun receiveUntil(untilByte: UByte): Array<UByte> { + var stop = false + val payload: Array<UByte> = MutableList(0, { 0 }) + while (!stop) { + val b = this.inStream.readNBytes(1)[0] + if (b == untilByte) { + stop = true + continue + } else { + payload.add(b) + } + } + return payload + } +*/ + + override fun receive(length: ULong): Array<UByte> { + var length = length + val intMax = Int.MAX_VALUE.toULong() + val bytes: MutableList<Byte> = MutableList(0) { 0 } + // readNBytes only takes Int values, so it must be called multiple times if the length is greater than Int's + // maximum value + while (length > 0u) { + // the min function ensures that the value passed to readNBytes never exceeds Int's maximum value while also + // switching to the length variable when its value eventually becomes less than Int's maximum value, which + // avoids writing duplicated readNBytes calls in the code + val lenMin = min(length, intMax) + bytes += this.inStream.readNBytes(lenMin.toInt()).toMutableList() + length -= intMax + } + return Array(bytes.size) { i -> bytes[i].toUByte() } + } + + override fun receiver(): Iterable<UByte> { + return Iterable { InStreamIterator(this.inStream) } + } +}
\ No newline at end of file |