introduced Checksum::PseudoHeader helper.

git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@20717 a95241bf-73f2-0310-859d-f6bbb57e9c96

headers/private/net/NetUtilities.h

@@ -9,6 +9,8 @@
 #include <net_buffer.h>
 #include <net_datalink.h>
 
+#include <netinet/in.h> // for htons
+
 #include <stdlib.h>
 
 class Checksum {
@@ -32,6 +34,10 @@ class Checksum {
 	
 		operator uint16();
 
+		static uint16 PseudoHeader(net_address_module_info *addressModule,
+			net_buffer_module_info *bufferModule, net_buffer *buffer,
+			uint16 protocol);
+
 	private:	
 		uint32 fSum;
 };
@@ -77,6 +83,19 @@ inline Checksum::operator uint16() {
 }
 
 
+inline uint16
+Checksum::PseudoHeader(net_address_module_info *addressModule,
+	net_buffer_module_info *bufferModule, net_buffer *buffer, uint16 protocol)
+{
+	Checksum checksum;
+	addressModule->checksum_address(&checksum, (sockaddr *)&buffer->source);
+	addressModule->checksum_address(&checksum, (sockaddr *)&buffer->destination);
+	checksum << (uint16)htons(protocol) << (uint16)htons(buffer->size)
+		<< Checksum::BufferHelper(buffer, bufferModule);
+	return checksum;
+}
+
+
 // helper class that prints an address (and optionally a port) into a buffer that 
 // is automatically freed at end of scope:
 class AddressString {

src/add-ons/kernel/network/protocols/tcp/tcp.cpp

@@ -161,16 +161,8 @@ add_tcp_header(tcp_segment_header &segment, net_buffer *buffer)
 	TRACE(("add_tcp_header(): buffer %p, flags 0x%x, seq %lu, ack %lu, win %u\n", buffer,
 		segment.flags, segment.sequence, segment.acknowledge, segment.advertised_window));
 
-	// compute and store checksum
-	Checksum checksum;
-	gAddressModule->checksum_address(&checksum, (sockaddr *)&buffer->source);
-	gAddressModule->checksum_address(&checksum, (sockaddr *)&buffer->destination);
-	checksum
-		<< (uint16)htons(IPPROTO_TCP)
-		<< (uint16)htons(buffer->size)
-		<< Checksum::BufferHelper(buffer, gBufferModule);
-
-	*TCPChecksumField(buffer) = checksum;
+	*TCPChecksumField(buffer) = Checksum::PseudoHeader(gAddressModule,
+		gBufferModule, buffer, IPPROTO_TCP);
 
 	return B_OK;
 }
@@ -518,15 +510,8 @@ tcp_receive_data(net_buffer *buffer)
 	if (headerLength < sizeof(tcp_header))
 		return B_BAD_DATA;
 
-	// compute checksum using a pseudo IP header
-	Checksum checksum;
-	gAddressModule->checksum_address(&checksum, (sockaddr *)&buffer->source);
-	gAddressModule->checksum_address(&checksum, (sockaddr *)&buffer->destination);
-	checksum << (uint16)htons(IPPROTO_TCP)
-		<< (uint16)htons(buffer->size)
-		<< Checksum::BufferHelper(buffer, gBufferModule);
-
-	if (checksum != 0)
+	if (Checksum::PseudoHeader(gAddressModule, gBufferModule, buffer,
+			IPPROTO_TCP) != 0)
 		return B_BAD_DATA;
 
 	gAddressModule->set_port((struct sockaddr *)&buffer->source, header.source_port);

src/add-ons/kernel/network/protocols/udp/udp.cpp

@@ -617,16 +617,8 @@ UdpEndpointManager::Deframe(net_buffer *buffer)
 
 	if (header.udp_checksum != 0) {
 		// check UDP-checksum (simulating a so-called "pseudo-header"):
-		Checksum udpChecksum;
-		addressModule->checksum_address(&udpChecksum, source);
-		addressModule->checksum_address(&udpChecksum, destination);
-		udpChecksum
-			<< (uint16)htons(IPPROTO_UDP)
-			<< header.udp_length
-					// peculiar but correct: UDP-len is used twice for checksum
-					// (as it is already contained in udp_header)
-			<< Checksum::BufferHelper(buffer, gBufferModule);
-		uint16 sum = udpChecksum;
+		uint16 sum = Checksum::PseudoHeader(addressModule, gBufferModule,
+			buffer, IPPROTO_UDP);
 		if (sum != 0) {
 			TRACE_EPM("  Deframe(): bad checksum 0x%hx.", sum);
 			return B_BAD_VALUE;
@@ -881,20 +873,8 @@ UdpEndpoint::SendRoutedData(net_buffer *buffer, net_route *route)
 
 	header.Sync();
 
-	// generate UDP-checksum (simulating a so-called "pseudo-header"):
-	Checksum udpChecksum;
-	AddressModule()->checksum_address(&udpChecksum,
-		(sockaddr *)route->interface->address);
-	AddressModule()->checksum_address(&udpChecksum,
-		(sockaddr *)&buffer->destination);
-	udpChecksum
-		<< (uint16)htons(IPPROTO_UDP)
-		<< (uint16)htons(buffer->size)
-				// peculiar but correct: UDP-len is used twice for checksum
-				// (as it is already contained in udp_header)
-		<< Checksum::BufferHelper(buffer, gBufferModule);
-
-	uint16 calculatedChecksum = udpChecksum;
+	uint16 calculatedChecksum = Checksum::PseudoHeader(AddressModule(),
+		gBufferModule, buffer, IPPROTO_UDP);
 	if (calculatedChecksum == 0)
 		calculatedChecksum = 0xffff;