From ec753ce95dd91dec1f8e98b3054a124cb24bdd75 Mon Sep 17 00:00:00 2001 From: Dean Armstrong Date: Tue, 22 Jun 2010 11:59:26 +0100 Subject: [PATCH] Bug 881: Bring Wi-Fi IE serdes intelligence into WifiInformationElement object Introduce WifiInformationElement methods SerializeIE(), DeserializeIE(), and DeserializeOptionalIE() (the latter for use when the IE of interest might not be present), which know how to deal with the IE as a whole. Make use of these in mesh subsystem where WifiInformationElement-derived objects are used. Also add empty implementation of Print() method of WifiInformationElement so that IEs that don't care about being displayed don't need to implement this. --- src/devices/mesh/dot11s/peer-link-frame.cc | 15 ++---- .../wifi/wifi-information-element-vector.cc | 5 +- src/devices/wifi/wifi-information-element.cc | 54 +++++++++++++++++++ src/devices/wifi/wifi-information-element.h | 33 ++++++++++-- 4 files changed, 87 insertions(+), 20 deletions(-) diff --git a/src/devices/mesh/dot11s/peer-link-frame.cc b/src/devices/mesh/dot11s/peer-link-frame.cc index e47f618de..b0769ddee 100644 --- a/src/devices/mesh/dot11s/peer-link-frame.cc +++ b/src/devices/mesh/dot11s/peer-link-frame.cc @@ -140,10 +140,7 @@ PeerLinkFrameStart::Serialize (Buffer::Iterator start) const { Buffer::Iterator i = start; NS_ASSERT (m_subtype < 3); - i.WriteU8 (IE11S_MESH_PEERING_PROTOCOL_VERSION); - i.WriteU8 (m_protocol.GetInformationSize ()); - m_protocol.SerializeInformation (i); - i.Next (m_protocol.GetInformationSize ()); + i = m_protocol.SerializeIE (i); if ((uint8_t) (WifiActionHeader::PEER_LINK_CLOSE) != m_subtype) { i.WriteHtolsbU16 (m_capability); @@ -158,17 +155,11 @@ PeerLinkFrameStart::Serialize (Buffer::Iterator start) const } if ((uint8_t) (WifiActionHeader::PEER_LINK_CONFIRM) != m_subtype) { - i.WriteU8 (IE11S_MESH_ID); - i.WriteU8 (m_meshId.GetInformationSize ()); - m_meshId.SerializeInformation (i); - i.Next (m_meshId.GetInformationSize ()); + i = m_meshId.SerializeIE (i); } if ((uint8_t) (WifiActionHeader::PEER_LINK_CLOSE) != m_subtype) { - i.WriteU8 (IE11S_MESH_CONFIGURATION); - i.WriteU8 (m_config.GetInformationSize ()); - m_config.SerializeInformation (i); - i.Next (m_config.GetInformationSize ()); + i = m_config.SerializeIE (i); } else { diff --git a/src/devices/wifi/wifi-information-element-vector.cc b/src/devices/wifi/wifi-information-element-vector.cc index 9bc7e7114..6483765b5 100644 --- a/src/devices/wifi/wifi-information-element-vector.cc +++ b/src/devices/wifi/wifi-information-element-vector.cc @@ -59,10 +59,7 @@ WifiInformationElementVector::Serialize (Buffer::Iterator start) const { for(IE_VECTOR::const_iterator i = m_elements.begin (); i != m_elements.end (); i ++) { - start.WriteU8((*i)->ElementId ()); - start.WriteU8 ((*i)->GetInformationSize ()); - (*i)->SerializeInformation (start); - start.Next ((*i)->GetInformationSize ()); + start = (*i)->SerializeIE (start); } } uint32_t diff --git a/src/devices/wifi/wifi-information-element.cc b/src/devices/wifi/wifi-information-element.cc index 753e782ea..e382e4ec7 100644 --- a/src/devices/wifi/wifi-information-element.cc +++ b/src/devices/wifi/wifi-information-element.cc @@ -25,6 +25,60 @@ namespace ns3 { WifiInformationElement::~WifiInformationElement () {} +void +WifiInformationElement::Print (std::ostream &os) const +{} + +uint16_t +WifiInformationElement::GetSerializedSize () const +{ + return (2 + GetInformationSize ()); +} + +Buffer::Iterator +WifiInformationElement::SerializeIE (Buffer::Iterator i) const +{ + i.WriteU8 (ElementId ()); + i.WriteU8 (GetInformationSize ()); + SerializeInformation (i); + i.Next (GetInformationSize ()); + return i; +} + +Buffer::Iterator +WifiInformationElement::DeserializeIE (Buffer::Iterator i) +{ + Buffer::Iterator start = i; + i = DeserializeOptionalIE (i); + // This IE was not optional, so confirm that we did actually + // deserialise something. + NS_ASSERT (i.GetDistanceFrom (start) != 0); + return i; +} + +Buffer::Iterator +WifiInformationElement::DeserializeOptionalIE (Buffer::Iterator i) +{ + Buffer::Iterator start = i; + uint8_t elementId = i.ReadU8 (); + + // If the element here isn't the one we're after then we immediately + // return the iterator we were passed indicating that we haven't + // taken anything from the buffer. + if (elementId != ElementId ()) + { + return start; + } + + uint8_t length = i.ReadU8 (); + + DeserializeInformation (i, length); + i.Next (length); + + return i; +} + + bool WifiInformationElement::operator< (WifiInformationElement const & a) const { diff --git a/src/devices/wifi/wifi-information-element.h b/src/devices/wifi/wifi-information-element.h index ef0c4a93c..19d39149d 100644 --- a/src/devices/wifi/wifi-information-element.h +++ b/src/devices/wifi/wifi-information-element.h @@ -136,25 +136,50 @@ class WifiInformationElement : public SimpleRefCount { public: virtual ~WifiInformationElement (); + /// Serialize entire IE including Element ID and length fields + Buffer::Iterator SerializeIE (Buffer::Iterator i) const; + /// Deserialize entire IE, which must be present. The iterator + /// passed in must be pointing at the Element ID (i.e., the very + /// first octet) of the correct type of information element, + /// otherwise this method will generate a fatal error. + Buffer::Iterator DeserializeIE (Buffer::Iterator i); + /// Deserialize entire IE if it is present. The iterator passed in + /// must be pointing at the Element ID of an information element. If + /// the Element ID is not the one that the given class is interested + /// in then it will return the same iterator. + Buffer::Iterator DeserializeOptionalIE (Buffer::Iterator i); + /// Get the size of the serialized IE including Element ID and + /// length fields. + uint16_t GetSerializedSize () const; + ///\name Each subclass must implement //\{ - virtual void Print (std::ostream &os) const = 0; /// Own unique Element ID virtual WifiInformationElementId ElementId () const = 0; - /// Length of serialized information + /// Length of serialized information (i.e., the length of the body + /// of the IE, not including the Element ID and length octets. This + /// is the value that will appear in the second octet of the entire + /// IE - the length field) virtual uint8_t GetInformationSize () const = 0; - /// Serialize information + /// Serialize information (i.e., the body of the IE, not including + /// the Element ID and length octets) virtual void SerializeInformation (Buffer::Iterator start) const = 0; - /// Deserialize information + /// Deserialize information (i.e., the body of the IE, not including + /// the Element ID and length octets) virtual uint8_t DeserializeInformation (Buffer::Iterator start, uint8_t length) = 0; //\} + /// In addition, a subclass may optionally override the following... + //\{ + /// Generate human-readable form of IE + virtual void Print (std::ostream &os) const; /// Compare information elements using Element ID virtual bool operator< (WifiInformationElement const & a) const; /// Compare two IEs for equality by ID & Length, and then through /// memcmp of serialised version virtual bool operator== (WifiInformationElement const & a) const; + //\} }; }