ttl.cc

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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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