ttl.cc

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/* -*-  Mode:C++; c-basic-offset:8; tab-width:8; indent-tabs-mode:t -*- */
/*
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 *  This product includes software developed by the MASH Research
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#ifndef lint
static const char rcsid[] =
    "@(#) $Header: /nfs/jade/vint/CVSROOT/ns-2/common/ttl.cc,v 1.11 1998/08/12 23:41:24 gnguyen Exp $";
#endif

#include "packet.h"
#include "ip.h"
#include "connector.h"

class TTLChecker : public Connector {
public:
    TTLChecker() : noWarn_(1), tick_(1) {}
    int command(int argc, const char*const* argv) {
        if (argc == 3) {
            if (strcmp(argv[1], "warning") == 0) {
                noWarn_ = ! atoi(argv[2]);
                return TCL_OK;
            }
            if (strcmp(argv[1], "tick") == 0) {
                int tick = atoi(argv[2]);
                if (tick > 0) {
                    tick_ = tick;
                    return TCL_OK;
                } else {
                    Tcl& tcl = Tcl::instance();
                    tcl.resultf("%s: TTL must be positive (specified = %d)\n",
                            name(), tick);
                    return TCL_ERROR;
                }
            }
        }
        return Connector::command(argc, argv);
    }
    void recv(Packet* p, Handler* h) {
        hdr_ip* iph = hdr_ip::access(p);
        int ttl = iph->ttl() - tick_;
        if (ttl <= 0) {
            /* XXX should send to a drop object.*/
            // Yes, and now it does...
            // Packet::free(p);
            if (! noWarn_)
                printf("ttl exceeded\n");
            drop(p);
            return;
        }
        iph->ttl() = ttl;
        send(p, h);
    }
protected:
    int noWarn_;
    int tick_;
};

static class TTLCheckerClass : public TclClass {
public:
    TTLCheckerClass() : TclClass("TTLChecker") {}
    TclObject* create(int, const char*const*) {
        return (new TTLChecker);
    }
} ttl_checker_class;


class SessionTTLChecker : public Connector {
public:
    SessionTTLChecker() {}
    int command(int argc, const char*const* argv);
    void recv(Packet* p, Handler* h) {
        hdr_ip* iph = hdr_ip::access(p);
        int ttl = iph->ttl() - tick_;
        if (ttl <= 0) {
            /* XXX should send to a drop object.*/
            // Yes, and now it does...
            // Packet::free(p);
            printf("ttl exceeded\n");
            drop(p);
            return;
        }
        iph->ttl() = ttl;
        send(p, h);
    }
protected:
    int tick_;
};

static class SessionTTLCheckerClass : public TclClass {
public:
    SessionTTLCheckerClass() : TclClass("TTLChecker/Session") {}
    TclObject* create(int, const char*const*) {
        return (new SessionTTLChecker);
    }
} session_ttl_checker_class;

int SessionTTLChecker::command(int argc, const char*const* argv)
{
    if (argc == 3) {
        if (strcmp(argv[1], "tick") == 0) {
            tick_ = atoi(argv[2]);
            return (TCL_OK);
        }
    }
    return (Connector::command(argc, argv));
}

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