traffic-control: Add a Hash method to QueueDiscItem

src/internet/model/ipv4-queue-disc-item.cc

@@ -18,6 +18,8 @@
 
 #include "ns3/log.h"
 #include "ipv4-queue-disc-item.h"
+#include "ns3/tcp-header.h"
+#include "ns3/udp-header.h"
 
 namespace ns3 {
 
@@ -109,4 +111,59 @@ Ipv4QueueDiscItem::GetUint8Value (QueueItem::Uint8Values field, uint8_t& value)
   return ret;
 }
 
+uint32_t
+Ipv4QueueDiscItem::Hash (uint32_t perturbation) const
+{
+  NS_LOG_FUNCTION (this << perturbation);
+
+  Ipv4Address src = m_header.GetSource ();
+  Ipv4Address dest = m_header.GetDestination ();
+  uint8_t prot = m_header.GetProtocol ();
+  uint16_t fragOffset = m_header.GetFragmentOffset ();
+
+  TcpHeader tcpHdr;
+  UdpHeader udpHdr;
+  uint16_t srcPort = 0;
+  uint16_t destPort = 0;
+
+  if (prot == 6 && fragOffset == 0) // TCP
+    {
+      GetPacket ()->PeekHeader (tcpHdr);
+      srcPort = tcpHdr.GetSourcePort ();
+      destPort = tcpHdr.GetDestinationPort ();
+    }
+  else if (prot == 17 && fragOffset == 0) // UDP
+    {
+      GetPacket ()->PeekHeader (udpHdr);
+      srcPort = udpHdr.GetSourcePort ();
+      destPort = udpHdr.GetDestinationPort ();
+    }
+  if (prot != 6 && prot != 17)
+    {
+      NS_LOG_WARN ("Unknown transport protocol, no port number included in hash computation");
+    }
+
+  /* serialize the 5-tuple and the perturbation in buf */
+  uint8_t buf[17];
+  src.Serialize (buf);
+  dest.Serialize (buf + 4);
+  buf[8] = prot;
+  buf[9] = (srcPort >> 8) & 0xff;
+  buf[10] = srcPort & 0xff;
+  buf[11] = (destPort >> 8) & 0xff;
+  buf[12] = destPort & 0xff;
+  buf[13] = (perturbation >> 24) & 0xff;
+  buf[14] = (perturbation >> 16) & 0xff;
+  buf[15] = (perturbation >> 8) & 0xff;
+  buf[16] = perturbation & 0xff;
+
+  // Linux calculates jhash2 (jenkins hash), we calculate murmur3 because it is
+  // already available in ns-3
+  uint32_t hash = Hash32 ((char*) buf, 17);
+
+  NS_LOG_DEBUG ("Hash value " << hash);
+
+  return hash;
+}
+
 } // namespace ns3

src/internet/model/ipv4-queue-disc-item.h

@@ -82,6 +82,18 @@ public:
    */
   virtual bool Mark (void);
 
+  /**
+   * \brief Computes the hash of the packet's 5-tuple
+   *
+   * Computes the hash of the source and destination IP addresses, protocol
+   * number and, if the transport protocol is either UDP or TCP, the source
+   * and destination port
+   *
+   * \param perturbation hash perturbation value
+   * \return the hash of the packet's 5-tuple
+   */
+  virtual uint32_t Hash (uint32_t perturbation) const;
+
 private:
   /**
    * \brief Default constructor

src/internet/model/ipv6-queue-disc-item.cc

@@ -18,6 +18,8 @@
 
 #include "ns3/log.h"
 #include "ipv6-queue-disc-item.h"
+#include "ns3/tcp-header.h"
+#include "ns3/udp-header.h"
 
 namespace ns3 {
 
@@ -108,4 +110,58 @@ Ipv6QueueDiscItem::GetUint8Value (QueueItem::Uint8Values field, uint8_t& value)
   return ret;
 }
 
+uint32_t
+Ipv6QueueDiscItem::Hash (uint32_t perturbation) const
+{
+  NS_LOG_FUNCTION (this << perturbation);
+
+  Ipv6Address src = m_header.GetSourceAddress ();
+  Ipv6Address dest = m_header.GetDestinationAddress ();
+  uint8_t prot = m_header.GetNextHeader ();
+
+  TcpHeader tcpHdr;
+  UdpHeader udpHdr;
+  uint16_t srcPort = 0;
+  uint16_t destPort = 0;
+
+  if (prot == 6) // TCP
+    {
+      GetPacket ()->PeekHeader (tcpHdr);
+      srcPort = tcpHdr.GetSourcePort ();
+      destPort = tcpHdr.GetDestinationPort ();
+    }
+  else if (prot == 17) // UDP
+    {
+      GetPacket ()->PeekHeader (udpHdr);
+      srcPort = udpHdr.GetSourcePort ();
+      destPort = udpHdr.GetDestinationPort ();
+    }
+  if (prot != 6 && prot != 17)
+    {
+      NS_LOG_WARN ("Unknown transport protocol, no port number included in hash computation");
+    }
+
+  /* serialize the 5-tuple and the perturbation in buf */
+  uint8_t buf[41];
+  src.Serialize (buf);
+  dest.Serialize (buf + 16);
+  buf[32] = prot;
+  buf[33] = (srcPort >> 8) & 0xff;
+  buf[34] = srcPort & 0xff;
+  buf[35] = (destPort >> 8) & 0xff;
+  buf[36] = destPort & 0xff;
+  buf[37] = (perturbation >> 24) & 0xff;
+  buf[38] = (perturbation >> 16) & 0xff;
+  buf[39] = (perturbation >> 8) & 0xff;
+  buf[40] = perturbation & 0xff;
+
+  // Linux calculates jhash2 (jenkins hash), we calculate murmur3 because it is
+  // already available in ns-3
+  uint32_t hash = Hash32 ((char*) buf, 41);
+
+  NS_LOG_DEBUG ("Found Ipv6 packet; hash of the five tuple " << hash);
+
+  return hash;
+}
+
 } // namespace ns3

src/internet/model/ipv6-queue-disc-item.h

@@ -82,6 +82,18 @@ public:
    */
   virtual bool Mark (void);
 
+  /**
+   * \brief Computes the hash of the packet's 5-tuple
+   *
+   * Computes the hash of the source and destination IP addresses, protocol
+   * number and, if the transport protocol is either UDP or TCP, the source
+   * and destination port
+   *
+   * \param perturbation hash perturbation value
+   * \return the hash of the packet's 5-tuple
+   */
+  virtual uint32_t Hash (uint32_t perturbation) const;
+
 private:
   /**
    * \brief Default constructor

src/network/utils/queue-item.cc

@@ -139,4 +139,11 @@ QueueDiscItem::Print (std::ostream& os) const
   ;
 }
 
+uint32_t
+QueueDiscItem::Hash (uint32_t perturbation) const
+{
+  NS_LOG_WARN ("The Hash method should be redefined by subclasses");
+  return 0;
+}
+
 } // namespace ns3

src/network/utils/queue-item.h

@@ -215,6 +215,17 @@ public:
    */
   virtual bool Mark (void) = 0;
 
+  /**
+   * \brief Computes the hash of various fields of the packet header
+   *
+   * This method just returns 0. Subclasses should implement a reasonable hash
+   * for their protocol type, such as hashing on the TCP/IP 5-tuple.
+   *
+   * \param perturbation hash perturbation value
+   * \return the hash of various fields of the packet header
+   */
+  virtual uint32_t Hash (uint32_t perturbation = 0) const;
+
 private:
   /**
    * \brief Default constructor