uwstaticrouting.cpp

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//
// Copyright (c) 2017 Regents of the SIGNET lab, University of Padova.
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions
// are met:
// 1. Redistributions of source code must retain the above copyright
//    notice, this list of conditions and the following disclaimer.
// 2. Redistributions in binary form must reproduce the above copyright
//    notice, this list of conditions and the following disclaimer in the
//    documentation and/or other materials provided with the distribution.
// 3. Neither the name of the University of Padova (SIGNET lab) nor the
//    names of its contributors may be used to endorse or promote products
//    derived from this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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//
 
#include <stdlib.h>
 
#include "uwstaticrouting.h"
 
static class UwStaticRoutingModuleClass : public TclClass
{
public:
    UwStaticRoutingModuleClass()
        : TclClass("Module/UW/StaticRouting")
    {
    }
 
    TclObject *
    create(int, const char *const *)
    {
        return (new UwStaticRoutingModule);
    }
} class_uwstaticrouting_module;
 
UwStaticRoutingModule::UwStaticRoutingModule()
    : default_gateway(0)
{
    clearRoutes();
}
 
UwStaticRoutingModule::~UwStaticRoutingModule()
{
}
 
int
UwStaticRoutingModule::recvSyncClMsg(ClMessage *m)
{
    return Module::recvSyncClMsg(m);
}
 
void
UwStaticRoutingModule::clearRoutes()
{
    routing_table.clear();
}
 
void
UwStaticRoutingModule::addRoute(const uint8_t &dst, const uint8_t &next)
{
    if (dst == 0 || next == 0) {
        std::cerr << "You are trying to insert an invalid entry in the routing "
                     "table with destination: "
                  << static_cast<uint32_t>(dst)
                  << " and next hop: " << static_cast<uint32_t>(next)
                  << std::endl;
        exit(EXIT_FAILURE);
    }
    std::map<uint8_t, uint8_t>::iterator it = routing_table.find(dst);
    if (it != routing_table.end()) {
        it->second = next;
        return;
    } else {
        if (routing_table.size() < IP_ROUTING_MAX_ROUTES) {
            routing_table.insert(std::pair<uint8_t, uint8_t>(dst, next));
            return;
        } else {
            std::cerr << "The routing table is full!" << std::endl;
            return;
        }
    }
}
 
int
UwStaticRoutingModule::command(int argc, const char *const *argv)
{
    Tcl &tcl = Tcl::instance();
    if (argc == 2) {
        if (strcasecmp(argv[1], "numroutes") == 0) {
            tcl.resultf("%d", routing_table.size());
            return TCL_OK;
        }
        if (strcasecmp(argv[1], "clearroutes") == 0) {
            clearRoutes();
            return TCL_OK;
        }
    } else if (argc == 3) {
        if (strcasecmp(argv[1], "defaultGateway") == 0) {
            if (static_cast<uint8_t>(atoi(argv[2])) != 0) {
                default_gateway = static_cast<uint8_t>(atoi(argv[2]));
            } else {
                std::cerr << "You are trying to set an invalid address as "
                             "default gateway. Exiting ..."
                          << std::endl;
                exit(EXIT_FAILURE);
            }
            return TCL_OK;
        }
 
    } else if (argc == 4) {
        if (strcasecmp(argv[1], "addroute") == 0) {
            addRoute(static_cast<uint8_t>(atoi(argv[2])),
                    static_cast<uint8_t>(atoi(argv[3])));
            return TCL_OK;
        }
    }
    return Module::command(argc, argv);
}
 
void
UwStaticRoutingModule::recv(Packet *p)
{
    hdr_cmn *ch = HDR_CMN(p);
    hdr_uwip *uwiph = HDR_UWIP(p);
 
    if (debug_) {
        std::cout << NOW << "::UWSTATICROUTING::RECV"
                  << "::NEXT_HOP::" << ch->next_hop()
                  << "::DESTINATION_IP::" << (uint)uwiph->daddr()
                  << std::endl;
    }
 
    if (ch->direction() == hdr_cmn::UP) {
 
        if (uwiph->daddr() == ch->next_hop() ||
                uwiph->daddr() ==
                        UWIP_BROADCAST) { /* Packet is arrived at its
                                             destination */
            sendUp(p);
            return;
        }
        /* Forward Packet */
        ch->direction() = hdr_cmn::DOWN;
        ch->next_hop() = getNextHop(p);
        if (ch->next_hop() == 0) {
            drop(p, 1, DROP_DEST_NO_ROUTE);
        } else {
            sendDown(p);
        }
    } else { /* direction DOWN */
        ch->next_hop() = getNextHop(p);
        if (ch->next_hop() == 0) {
            drop(p, 1, DROP_DEST_NO_ROUTE);
        } else {
            sendDown(p);
        }
    }
}
 
uint8_t
UwStaticRoutingModule::getNextHop(const Packet *p) const
{
    hdr_uwip *uwiph = HDR_UWIP(p);
    return getNextHop(uwiph->daddr());
}
 
uint8_t
UwStaticRoutingModule::getNextHop(const uint8_t &dst) const
{
    std::map<uint8_t, uint8_t>::const_iterator it = routing_table.find(dst);
    if (it != routing_table.end()) {
        return it->second;
    } else {
        if (default_gateway != 0) {
            return default_gateway;
        } else {
            return 0;
        }
    }
}