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package io.pkts.packet.sip.impl;
import io.pkts.buffer.Buffer;
import io.pkts.buffer.Buffers;
import io.pkts.packet.sip.SipMessage;
import io.pkts.packet.sip.SipParseException;
import io.pkts.packet.sip.header.ContentLengthHeader;
import io.pkts.packet.sip.header.SipHeader;
import io.pkts.packet.sip.header.impl.SipHeaderImpl;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import java.util.function.Function;
/**
* A very specialized SIP message builder for streams and is also highly specific
* to how ByteBuf's within Netty works.
*
* @author [email protected]
*/
public class SipMessageStreamBuilder {
private Configuration config;
private State state = State.INIT;
/**
* Because the beginning of the buffer could contain stuff we don't care
* about so we have to mask that away.
*/
private int start;
private SipInitialLine sipInitialLine;
private Buffer buffer;
private Buffer payload = Buffers.EMPTY_BUFFER;
// Move along as long as we actually can consume an header and
private Buffer headerName = null;
private List headers = new ArrayList<>();
private short count;
private int contentLength;
private short indexOfTo = -1;
private short indexOfFrom = -1;
private short indexOfCSeq = -1;
private short indexOfCallId = -1;
private short indexOfMaxForwards = -1;
private short indexOfVia = -1;
private short indexOfRoute = -1;
private short indexOfRecordRoute = -1;
private short indexOfContact = -1;
private SipParser.HeaderValueState headerValueState;
private final Function[] actions = new Function[State.values().length];
public SipMessageStreamBuilder(final Configuration config) {
this.config = config;
resetBuffer();
reset();
headerValueState = new SipParser.HeaderValueState(0);
actions[State.INIT.ordinal()] = this::onInit;
actions[State.GET_INITIAL_LINE.ordinal()] = this::onInitialLine;
actions[State.GET_HEADER_NAME.ordinal()] = this::onHeaderName;
actions[State.CONSUME_HCOLON.ordinal()] = this::onConsumeHColon;
actions[State.CONSUME_SWS_AFTER_HCOLON.ordinal()] = this::onConsumeSWSAfterHColon;
actions[State.GET_HEADER_VALUES.ordinal()] = this::onHeaderValues;
actions[State.CHECK_FOR_END_OF_HEADER_SECTION.ordinal()] = this::onCheckEndHeaderSection;
actions[State.GET_PAYLOAD.ordinal()] = this::onPayload;
actions[State.DONE.ordinal()] = this::onDone;
}
private void resetBuffer() {
buffer = Buffers.createBuffer(config.getMaxAllowedInitialLineSize()
+ config.getMaxAllowedHeadersSize()
+ config.getMaxAllowedContentLength());
}
private void reset() {
state = State.INIT;
payload = Buffers.EMPTY_BUFFER;
sipInitialLine = null;
start = 0;
headerName = null;
headers = new ArrayList<>();
count = 0;
contentLength = 0;
indexOfTo = -1;
indexOfFrom = -1;
indexOfCSeq = -1;
indexOfCallId = -1;
indexOfMaxForwards = -1;
indexOfVia = -1;
indexOfRoute = -1;
indexOfRecordRoute = -1;
indexOfContact = -1;
}
public SipMessage build() throws IllegalStateException {
if (state != State.DONE) {
throw new IllegalStateException("We have not framed enough data for a complete message yet");
}
// final byte[] array = buffer.getRawArray();
// final byte[] msgArray = new byte[buffer.getReaderIndex() - start];
// System.arraycopy(array, start, msgArray, 0, msgArray.length);
// final Buffer msg = Buffers.wrap(msgArray);
// There may be extra data left after we have processed
// the one SIP message. If there is, we want to preserve that
// data by copying it over to the beginning of the next buffer
// so mark the start and stop, hide that portion to the old
// buffer and then copy it over to the new
final int extraDataStart = buffer.getReaderIndex();
final int length = buffer.getWriterIndex() - extraDataStart;
// hide in old. Remember that the 'start' value is
// were the data of this message actually starts as in
// there may have been empty spaces and what not in the beginning
// of the data and that has to be masked away, which is done by
// manipulating the reader index.
final Buffer msg = buffer;
msg.setWriterIndex(msg.getReaderIndex());
msg.setReaderIndex(start);
// reset and copy over
resetBuffer();
final byte[] oldData = msg.getRawArray();
final byte[] newData = buffer.getRawArray();
System.arraycopy(oldData, extraDataStart, newData, 0, length);
buffer.setWriterIndex(length);
SipMessage sipMessage = null;
if (sipInitialLine.isRequestLine()) {
sipMessage = new ImmutableSipRequest(msg, sipInitialLine.toRequestLine(), headers,
indexOfTo,
indexOfFrom,
indexOfCSeq,
indexOfCallId,
indexOfMaxForwards,
indexOfVia,
indexOfRoute,
indexOfRecordRoute,
indexOfContact,
payload);
} else {
sipMessage = new ImmutableSipResponse(msg, sipInitialLine.toResponseLine(), headers,
indexOfTo,
indexOfFrom,
indexOfCSeq,
indexOfCallId,
indexOfMaxForwards,
indexOfVia,
indexOfRoute,
indexOfRecordRoute,
indexOfContact,
payload);
}
reset();
return sipMessage;
}
public int getWriterIndex() {
return buffer.getWriterIndex();
}
public int getWritableBytes() {
return buffer.getWritableBytes();
}
/**
* After you have actually constructed a new {@link SipMessage} there may
* be other messages behind it in the same stream, or parts of one. Therefore,
* after you have {@link #build()} a message you can check if there are still
* data available and if so, call {@link #process()} to kick off more
* processing.
*
* @return if there are more data available for processing
*/
public boolean hasUnprocessData() {
return buffer.hasReadableBytes();
}
/**
*
* @return true if a message is ready to be built.
*/
public boolean process() {
return process(null);
}
/**
* Process more incoming data.
*
* @param newData
* @return
*/
public boolean process(final byte[] newData) {
if (newData != null) {
buffer.write(newData);
}
boolean done = false;
while (!done) {
final int index = buffer.getReaderIndex();
final State currentState = state;
state = actions[state.ordinal()].apply(buffer);
done = state == currentState && buffer.getReaderIndex() == index;
}
return state == State.DONE;
}
public boolean isDone() {
return state == State.DONE;
}
/**
* Just so we don't have to check for null once we reach this state.
*
* @param buffer
* @return
*/
private final State onDone(final Buffer buffer) {
return State.DONE;
}
/**
* While in the INIT state, we are just consuming any empty space
* before heading off to start parsing the initial line
* @param b
* @return
*/
private final State onInit(final Buffer buffer) {
try {
while (buffer.hasReadableBytes()) {
final byte b = buffer.peekByte();
if (b == SipParser.SP || b == SipParser.HTAB || b == SipParser.CR || b == SipParser.LF) {
buffer.readByte();
} else {
start = buffer.getReaderIndex();
return State.GET_INITIAL_LINE;
}
}
} catch (final IOException e) {
throw new RuntimeException("Unable to read from stream due to IOException", e);
}
return State.INIT;
}
/**
* Since it is quite uncommon to not have enough data on the line
* to read the entire first line we are taking the simple approach
* of just resetting the entire effort and we'll retry later. This
* of course means that in the worst case scenario we will actually
* iterate over data we have already seen before. However, seemed
* like it is worth it instead of having the extra space for keeping
* track of the extra state.
*
* @param buffer
* @return
*/
private final State onInitialLine(final Buffer buffer) {
try {
buffer.markReaderIndex();
final Buffer part1 = buffer.readUntilSafe(config.getMaxAllowedInitialLineSize(), SipParser.SP);
final Buffer part2 = buffer.readUntilSafe(config.getMaxAllowedInitialLineSize(), SipParser.SP);
final Buffer part3 = buffer.readUntilSingleCRLF();
if (part1 == null || part2 == null || part3 == null) {
buffer.resetReaderIndex();
return State.GET_INITIAL_LINE;
}
sipInitialLine = SipInitialLine.parse(part1, part2, part3);
} catch (final IOException e) {
throw new RuntimeException("Unable to read from stream due to IOException", e);
}
return State.GET_HEADER_NAME;
}
private final State onHeaderName(final Buffer buffer) {
headerName = SipParser.nextHeaderNameDontCheckHColon(buffer);
// not enough data in the stream, go back to the same
// state and re-try when more data shows up.
if (headerName == null) {
return State.GET_HEADER_NAME;
}
return State.CONSUME_HCOLON;
}
/**
* Consume HCOLON but we need to be slightly smarter than what the SipParser
* is offering up since we may run out of bytes from the stream just as we
* received the ':' and as such, we also need to be prepared to continue
* the "other half" of the {@link SipParser#expectHCOLON(Buffer)}.
*
* @param buffer
* @return
*/
private final State onConsumeHColon(final Buffer buffer) {
try {
if (SipParser.expectHCOLONStreamFriendly(buffer) == -1) {
return State.CONSUME_HCOLON;
}
return State.CONSUME_SWS_AFTER_HCOLON;
} catch (final SipParseException e) {
throw e;
}
}
private final State onConsumeSWSAfterHColon(final Buffer buffer) {
try {
SipParser.consumeSWSAfterHColon(buffer);
// if we still have stuff left in the buffer that means
// that we must have consumed all SWS and then hit a non-sws
// character and as such, we are done.
// However, if there are no bytes left then we don't know
// if the next thing that is about to show up on the wire is
// yet another white spaces so therefore we have to once again
// go back to this method...
if (buffer.hasReadableBytes()) {
headerValueState.reset(buffer.getReaderIndex());
return State.GET_HEADER_VALUES;
} else {
return State.CONSUME_SWS_AFTER_HCOLON;
}
} catch (final IOException e) {
throw new RuntimeException("Unable to read from stream due to IOException", e);
}
}
private final State onHeaderValues(final Buffer buffer) {
try {
SipParser.readHeaderValues(headerValueState, headerName, buffer);
if (headerValueState.done) {
final List values = headerValueState.values;
for (final Buffer value : values) {
SipHeader header = new SipHeaderImpl(headerName, value);
// The headers that are most commonly used will be fully
// parsed just because no stack can really function without
// looking into these headers.
if (header.isContentLengthHeader()) {
final ContentLengthHeader l = header.ensure().toContentLengthHeader();
contentLength = l.getContentLength();
header = l;
} else if (header.isContactHeader() && indexOfContact == -1) {
header = header.ensure();
indexOfContact = count;
} else if (header.isCSeqHeader() && indexOfCSeq == -1) {
header = header.ensure();
indexOfCSeq = count;
} else if (header.isMaxForwardsHeader() && indexOfMaxForwards == -1) {
header = header.ensure();
indexOfMaxForwards = count;
} else if (header.isFromHeader() && indexOfFrom == -1) {
header = header.ensure();
indexOfFrom = count;
} else if (header.isToHeader() && indexOfTo == -1) {
header = header.ensure();
indexOfTo = count;
} else if (header.isViaHeader() && indexOfVia == -1) {
header = header.ensure();
indexOfVia = count;
} else if (header.isCallIdHeader() && indexOfCallId == -1) {
header = header.ensure();
indexOfCallId = count;
} else if (header.isRouteHeader() && indexOfRoute == -1) {
header = header.ensure();
indexOfRoute = count;
} else if (header.isRecordRouteHeader() && indexOfRecordRoute == -1) {
header = header.ensure();
indexOfRecordRoute = count;
}
headers.add(header);
++count;
}
return State.CHECK_FOR_END_OF_HEADER_SECTION;
}
return State.GET_HEADER_VALUES;
} catch (final IOException e) {
throw new RuntimeException("Unable to read from stream due to IOException", e);
}
}
/**
* Every time we have parsed a header we need to check if there are more headers or
* if we have reached the end of the section and as such there may be a body we need
* to take care of. We know this by checking if there is a CRLF up next or not.
*
* @param buffer
* @return
*/
private final State onCheckEndHeaderSection(final Buffer buffer) {
// can't tell. We need two bytes at least to check if there is
// more headers or not
if (buffer.getReadableBytes() < 2) {
return State.CHECK_FOR_END_OF_HEADER_SECTION;
}
// ok, so there was a CRLF so we are going to fetch the payload
// if there is one...
if (SipParser.consumeCRLF(buffer) == 2) {
return State.GET_PAYLOAD;
}
// nope, still headers
return State.GET_HEADER_NAME;
}
/**
* We may or may not have a payload, which depends on whether there is a Content-length
* header available or not. If yes, then we will just slice out that entire thing once
* we have enough readable bytes in the buffer.
*
* @param buffer
* @return
*/
private final State onPayload(final Buffer buffer) {
if (contentLength == 0) {
return State.DONE;
}
if (buffer.getReadableBytes() >= contentLength) {
try {
payload = buffer.readBytes(contentLength);
} catch (final IOException e) {
throw new RuntimeException("Unable to read from stream due to IOException", e);
}
return State.DONE;
}
return State.GET_PAYLOAD;
}
/**
* This is very very super duper ugly but is highly adapted to how netty and its buffers
* work and we are trying to avoid copying memory if we don't have to.
*
* @return
*/
public byte[] getArray() {
return buffer.getRawArray();
}
/**
* Configuration interface for controlling aspects of the {@link SipMessageStreamBuilder}. The
* reason for an interface for such a simple thing is that when building e.g. a real
* SIP stack you may want to allow a user to configure this in a config file using
* e.g. jackson and yaml but I didn't want to have that dependency on this library
* itself.
*/
public interface Configuration {
/**
* The maximum allowed initial line. If we pass this threshold we will drop
* the message and close down the connection (if we are using a connection
* oriented protocol ie)
*
* MAX_ALLOWED_INITIAL_LINE_SIZE = 1024;
*/
int getMaxAllowedInitialLineSize() ;
/**
* The maximum allowed size of ALL headers combined (in bytes).
*
* MAX_ALLOWED_HEADERS_SIZE = 8192;
*/
int getMaxAllowedHeadersSize() ;
/**
* MAX_ALLOWED_CONTENT_LENGTH = 2048;
*/
int getMaxAllowedContentLength();
}
public static class DefaultConfiguration implements Configuration {
private int maxAllowedInitialLineSize = 1024;
private int maxAllowedHeadersSize = 4096;
private int maxAllowedContentLength = 4096;
@Override
public int getMaxAllowedInitialLineSize() {
return maxAllowedInitialLineSize;
}
@Override
public int getMaxAllowedHeadersSize() {
return maxAllowedHeadersSize;
}
@Override
public int getMaxAllowedContentLength() {
return maxAllowedContentLength;
}
public void setMaxAllowedInitialLineSize(final int value) {
this.maxAllowedInitialLineSize = value;
}
public void setMaxAllowedHeadersSize(final int value) {
this.maxAllowedHeadersSize = value;
}
public void setMaxAllowedContentLength(final int value) {
this.maxAllowedContentLength = value;
}
}
private static enum State {
/**
* In the INIT state we will consume any CRLF we find. This is allowed
* for stream based protocols according to RFC 3261.
*/
INIT,
/**
* While in this state, we will consume the initial line in the SIP
* message. We will not verify it is correct that is up to later stages
* of the processing.
*/
GET_INITIAL_LINE,
GET_HEADER_NAME,
CONSUME_HCOLON,
CONSUME_SWS_AFTER_HCOLON,
GET_HEADER_VALUES,
CHECK_FOR_END_OF_HEADER_SECTION,
/**
* Once we have found the separator between the headers and the payload
* we will just blindly a byte at a time until we have read the entire
* payload. The length of the payload was discovered during the
* GET_HEADERS phase where we were not only just consuming all headers
* but we were looking for the Content-Length header as well.
*/
GET_PAYLOAD,
DONE;
}
}
