X-Git-Url: http://g0dil.de/git?a=blobdiff_plain;f=Packets%2FDefaultBundle%2FUDPPacket.cc;h=f3cfc56eb353e10fb5718d42e8bb1ac9c0423f92;hb=5443435c4c2b6e4386c5334b5b8358273f2bae93;hp=bc204b39b05e7cc89edfc2e27abc85993da1f9e9;hpb=03e6d8f7c983e22cdd021176a3190b7d34a2d8c5;p=senf.git

diff --git a/Packets/DefaultBundle/UDPPacket.cc b/Packets/DefaultBundle/UDPPacket.cc
index bc204b3..f3cfc56 100644
--- a/Packets/DefaultBundle/UDPPacket.cc
+++ b/Packets/DefaultBundle/UDPPacket.cc
@@ -1,8 +1,8 @@
 // $Id$
 //
 // Copyright (C) 2006
-// Fraunhofer Institute for Open Communication Systems (FOKUS) 
-// Competence Center NETwork research (NET), St. Augustin, GERMANY 
+// Fraunhofer Institute for Open Communication Systems (FOKUS)
+// Competence Center NETwork research (NET), St. Augustin, GERMANY
 //     Stefan Bund <g0dil@berlios.de>
 //
 // This program is free software; you can redistribute it and/or modify
@@ -50,10 +50,7 @@ prefix_ boost::uint16_t senf::UDPPacketParser::calcChecksum()
     const
 {
     IpChecksum summer;
-    summer.feed( i(), i()+checksum_offset );
-    summer.feed( i()+checksum_offset+2, data().end() );
-    
-    // Now on to the awkward part: the IP pseudo header
+    // first on to the awkward part: the IP pseudo header
     IPv4Packet ipv4 (packet().rfind<IPv4Packet>(nothrow));
     if (ipv4) {
         // Pseudo header defined in RFC768
@@ -78,8 +75,8 @@ prefix_ boost::uint16_t senf::UDPPacketParser::calcChecksum()
             // The destination used here must be the *final* destination ...
             summer.feed( ipv6->destination().i(), 
                          ipv6->destination().i() + IPv6PacketParser::destination_t::fixed_bytes );
-            /// This is a simplification. The value is really 32bit to support UDP Jumbograms
-            /// (RFC2147). However, skipping an even number of 0 bytes does not change the checksum
+            // This is a simplification. The value is really 32bit to support UDP Jumbograms
+            // (RFC2147). However, skipping an even number of 0 bytes does not change the checksum
             summer.feed( i() + length_offset, i() + length_offset + 2 );
             // RFC2460 specifies, that this must always be 17, not the value used in the ipv6
             // header
@@ -88,6 +85,11 @@ prefix_ boost::uint16_t senf::UDPPacketParser::calcChecksum()
         }
     }
     
+    // since header are 16 / even 32bit aligned we don't have to care for padding. since IpChecksum 
+    // cares for padding at the final summing we don't have to care is the payload is 16nbit-aligned, too.
+    summer.feed( i(), i()+checksum_offset );
+    summer.feed( i()+checksum_offset+2, data().end() );
+
     boost::uint16_t rv (summer.sum());
     return rv ? rv : 0xffffu;
 }