packet.cc

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/* -*-  Mode:C++; c-basic-offset:8; tab-width:8; indent-tabs-mode:t -*- */
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 * Copyright (c) 1994-1997 Regents of the University of California.
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 *      This product includes software developed by the Computer Systems
 *      Engineering Group at Lawrence Berkeley Laboratory.
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#ifndef lint
static const char rcsid[] =
    "@(#) $Header: /nfs/jade/vint/CVSROOT/ns-2/common/packet.cc,v 1.18 2000/09/15 20:32:57 haoboy Exp $ (LBL)";
#endif

#include "packet.h"
#include "flags.h"

p_info packet_info;
char* p_info::name_[PT_NTYPE+1];

int Packet::hdrlen_ = 0;                // size of a packet's header
Packet* Packet::free_;                  // free list
int hdr_cmn::offset_;                   // static offset of common header
int hdr_flags::offset_;                 // static offset of flags header


PacketHeaderClass::PacketHeaderClass(const char* classname, int hdrlen) : 
        TclClass(classname), hdrlen_(hdrlen), offset_(0)
{
}


TclObject* PacketHeaderClass::create(int, const char*const*)
{
        return (0);
}

void PacketHeaderClass::bind()
{
        TclClass::bind();
        Tcl& tcl = Tcl::instance();
        tcl.evalf("%s set hdrlen_ %d", classname_, hdrlen_);
        export_offsets();
        add_method("offset");
}

void PacketHeaderClass::export_offsets()
{
}

void PacketHeaderClass::field_offset(const char* fieldname, int offset)
{
        Tcl& tcl = Tcl::instance();
        tcl.evalf("%s set offset_(%s) %d", classname_, fieldname, offset);
}

int PacketHeaderClass::method(int ac, const char*const* av)
{
        Tcl& tcl = Tcl::instance();
        int argc = ac - 2;
        const char*const* argv = av + 2;
        if (argc == 3) {
                if (strcmp(argv[1], "offset") == 0) {
                        if (offset_) {
                                *offset_ = atoi(argv[2]);
                                return TCL_OK;
                        }
                        tcl.resultf("Warning: cannot set offset_ for %s",
                                    classname_);
                        return TCL_OK;
                }
        }
        else if (argc == 2) {
                if (strcmp(argv[1], "offset") == 0) {
                        if (offset_) {
                                tcl.resultf("%d", *offset_);
                                return TCL_OK;
                        }
                }
        }
        return TclClass::method(ac, av);
}


class CommonHeaderClass : public PacketHeaderClass {
public:
        CommonHeaderClass() : PacketHeaderClass("PacketHeader/Common",
                                                sizeof(hdr_cmn)) {
                bind_offset(&hdr_cmn::offset_);
        }
        void export_offsets() {
                field_offset("ptype_", OFFSET(hdr_cmn, ptype_));
                field_offset("size_", OFFSET(hdr_cmn, size_));
                field_offset("uid_", OFFSET(hdr_cmn, uid_));
                field_offset("error_", OFFSET(hdr_cmn, error_));
        };
} class_cmnhdr;

class FlagsHeaderClass : public PacketHeaderClass {
public:
        FlagsHeaderClass() : PacketHeaderClass("PacketHeader/Flags",
                                                sizeof(hdr_flags)) {
                bind_offset(&hdr_flags::offset_);
        }
} class_flagshdr;


/* manages active packet header types */
class PacketHeaderManager : public TclObject {
public:
        PacketHeaderManager() {
                bind("hdrlen_", &Packet::hdrlen_);
        }
};

static class PacketHeaderManagerClass : public TclClass {
public:
        PacketHeaderManagerClass() : TclClass("PacketHeaderManager") {}
        TclObject* create(int, const char*const*) {
                return (new PacketHeaderManager);
        }
} class_packethdr_mgr;

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