Added some helper methods to Dot1Q.

include/dot1q.h

@@ -44,7 +44,7 @@ public:
     /**
      * Default constructor
      */
-    Dot1Q();
+    Dot1Q(small_uint<12> tag_id = 0, bool append_pad = true);
 
     /**
      * \brief Constructor which creates an Dot1Q object from a buffer and 
@@ -120,6 +120,14 @@ public:
         return new Dot1Q(*this);
     }
 
+    /**
+     * \brief Retrieves the flag indicating whether padding will be
+     * appended at the end of this packet.
+     */
+    bool append_padding() const {
+        return _append_padding;
+    }
+
     // Setters
 
     /**
@@ -146,6 +154,18 @@ public:
      */
     void payload_type(uint16_t new_type);
     
+    /**
+     *  \brief Indicates whether the appropriate padding will be 
+     * at the end of the packet.
+     * 
+     * This flag could be disabled in case two or more contiguous Dot1Q 
+     * PDUs are added to a packet. In that case, only the Dot1Q which is 
+     * closer to the link layer should add the padding at the end.
+     * 
+     * \param value A boolean indicating whether padding will be appended.
+     */
+    void append_padding(bool value);
+    
     /** 
      * \brief Check wether ptr points to a valid response for this PDU.
      *
@@ -175,6 +195,7 @@ private:
     static uint16_t get_id(const dot1q_hdr *hdr);
     
     dot1q_hdr _header;
+    bool _append_padding;
 };
 }
 

include/tins.h

@@ -41,6 +41,8 @@
 #include "icmp.h"
 #include "icmpv6.h"
 #include "dot11.h"
+#include "dot1q.h"
+#include "dot3.h"
 #include "ip.h"
 #include "ipv6.h"
 #include "packet_sender.h"

src/dot1q.cpp

@@ -35,10 +35,10 @@
 
 namespace Tins {
 
-Dot1Q::Dot1Q() 
-: _header() 
+Dot1Q::Dot1Q(small_uint<12> tag_id, bool append_pad) 
+: _header(), _append_padding(append_pad)
 {
-    
+    id(tag_id);
 }
 
 Dot1Q::Dot1Q(const uint8_t *buffer, uint32_t total_sz) {
@@ -85,10 +85,14 @@ uint32_t Dot1Q::header_size() const {
 }
 
 uint32_t Dot1Q::trailer_size() const {
-    uint32_t total_size = sizeof(_header);
-    if(inner_pdu())
-        total_size += inner_pdu()->size();
-    return (total_size > 50) ? 0 : (50 - total_size);
+    if(_append_padding) {
+        uint32_t total_size = sizeof(_header);
+        if(inner_pdu())
+            total_size += inner_pdu()->size();
+        return (total_size > 50) ? 0 : (50 - total_size);
+    }
+    else
+        return 0;
 }
 
 void Dot1Q::write_serialization(uint8_t *buffer, uint32_t total_sz, const PDU *) {
@@ -118,6 +122,10 @@ void Dot1Q::write_serialization(uint8_t *buffer, uint32_t total_sz, const PDU *)
     }
 #endif
 
+void Dot1Q::append_padding(bool value) {
+    _append_padding = value;
+}
+
 bool Dot1Q::matches_response(uint8_t *ptr, uint32_t total_sz) {
     if(total_sz < sizeof(_header))
         return false;

src/internals.cpp

@@ -136,6 +136,8 @@ Constants::Ethernet::e pdu_flag_to_ether_type(PDU::PDUType flag) {
             return Constants::Ethernet::IPV6;
         case PDU::ARP:
             return Constants::Ethernet::ARP;
+        case PDU::DOT1Q:
+            return Constants::Ethernet::VLAN;
         default:
             return Constants::Ethernet::UNKNOWN;
     }