From 18d7b32946d09826ac393d68958a64dc08a5efe5 Mon Sep 17 00:00:00 2001
From: Chris Frey <cdfrey@foursquare.net>
Date: Fri, 16 May 2008 16:39:23 -0400
Subject: [PATCH] Localize sequence packet checking in SocketZero class

Put sequence packet check directly in the
SocketZero::RawReceive() function, which now localizes all
sequence packet handling and checking, as well as avoids
packet order problems when multiple sockets are in use,
such as with pppob...
FIXME - this localized sequence checking may make
all the calls to CheckSequence() obsolete, which
should probably be cleaned up someday, if so.
---
 ChangeLog     |  9 +++++++++
 src/socket.cc | 48 +++++++++++++++++++++++++++++++++++-------------
 src/socket.h  |  3 +++
 3 files changed, 47 insertions(+), 13 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 9a9dacef..95dc09ed 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,14 @@
 Release: version 0.13 - 2008/05/??
 ------------------------------------------------------------------------------
+2008/05/16
+	- put sequence packet check directly in the SocketZero::RawReceive()
+		function, which now localizes all sequence packet
+		handling and checking, as well as avoids packet
+		order problems when multiple sockets are in use,
+		such as with pppob...
+		FIXME - this localized sequence checking may make all
+		the calls to CheckSequence() obsolete which
+		should probably be cleaned up someday, if so.
 2008/05/15
 	- mention CVS and git on main documentation "how to" list
 	- moved PPP filter logic into its own class
diff --git a/src/socket.cc b/src/socket.cc
index c68f81ae..3b020eca 100644
--- a/src/socket.cc
+++ b/src/socket.cc
@@ -158,11 +158,6 @@ unsigned int SocketZero::MakeNextFragment(const Data &whole, Data &fragment, uns
 //
 void SocketZero::CheckSequence(uint16_t socket, const Data &seq)
 {
-//	if( m_socket == 0 ) {
-//		// don't do any sequence checking on socket 0
-//		return;
-//	}
-
 	MAKE_PACKET(spack, seq);
 	if( (unsigned int) seq.GetSize() < SB_SEQUENCE_PACKET_SIZE ) {
 		eout("Short sequence packet:\n" << seq);
@@ -329,15 +324,42 @@ void SocketZero::RawSend(Data &send, int timeout)
 
 void SocketZero::RawReceive(Data &receive, int timeout)
 {
-	if( m_queue ) {
-		if( !m_queue->DefaultRead(receive, timeout) )
-			throw Timeout("SocketZero::RawReceive: queue DefaultRead returned false (likely a timeout)");
-	}
-	else {
-		m_dev->BulkRead(m_readEp, receive, timeout);
+	do {
+		if( m_queue ) {
+			if( !m_queue->DefaultRead(receive, timeout) )
+				throw Timeout("SocketZero::RawReceive: queue DefaultRead returned false (likely a timeout)");
+		}
+		else {
+			m_dev->BulkRead(m_readEp, receive, timeout);
+		}
+		ddout("SocketZero::RawReceive: Endpoint " << m_readEp
+			<< "\nReceived:\n" << receive);
+	} while( SequencePacket(receive) );
+}
+
+//
+// SequencePacket
+//
+/// Returns true if this is a sequence packet that should be ignored.
+/// This function is used in SocketZero::RawReceive() in order
+/// to determine whether to keep reading or not.  By default,
+/// this function checks whether the packet is a sequence packet
+/// or not, and returns true if so.  Also, if it is a sequence
+/// packet, it checks the validity of the sequence number.
+///
+/// If sequence packets become important in the future, this
+/// function could be changed to call a user-defined callback,
+/// in order to handle these things out of band.
+///
+bool SocketZero::SequencePacket(const Data &data)
+{
+	if( data.GetSize() >= MIN_PACKET_SIZE ) {
+		if( IS_COMMAND(data, SB_COMMAND_SEQUENCE_HANDSHAKE) ) {
+			CheckSequence(0, data);
+			return true;
+		}
 	}
-	ddout("SocketZero::RawReceive: Endpoint " << m_readEp
-		<< "\nReceived:\n" << receive);
+	return false;	// not a sequence packet
 }
 
 void SocketZero::Send(Data &send, int timeout)
diff --git a/src/socket.h b/src/socket.h
index 3d72b701..0f2fc648 100644
--- a/src/socket.h
+++ b/src/socket.h
@@ -71,6 +71,9 @@ private:
 	void RawSend(Data &send, int timeout = -1);
 	void RawReceive(Data &receive, int timeout = -1);
 
+protected:
+	bool SequencePacket(const Data &data);
+
 public:
 	explicit SocketZero(SocketRoutingQueue &queue, int writeEndpoint,
 		uint8_t zeroSocketSequenceStart = 0);
-- 
2.11.4.GIT