Watchdog源码--neighboursPacketDetected

邻居包检测与转发机制

最新推荐文章于 2025-02-26 10:44:07 发布

转载最新推荐文章于 2025-02-26 10:44:07 发布 · 1.4k 阅读

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原文链接：http://www.cnblogs.com/zhangrui/archive/2012/03/08/2385236.html

本文详细解析了一种网络中邻居包的检测与转发机制，包括如何处理邻居发送的包，判断是否需要转发，以及如何将包添加到等待转发列表，并从列表中删除已转发的包。涉及的主要操作包括检测包、判断包是否有趣、判断是否需要转发、将包添加到邻居转发列表以及从列表中移除已转发的包。

/**
 * A packet from a neighbour has been detected.
*/
void
WATCHDOG::neighboursPacketDetected(int32_t source_ip, int32_t destination_ip, int source_mac, int destination_mac,  int sourcePort, int destinationPort, char * tmp_data, packet_t packet_type, double pktime) {
if (debug > 2) printf("NeighbourPacket\n");
    neighbour *neigh_src, *neigh_dst;
int data_size;

    data_size = strlen(tmp_data);
    protocol = packet_type;

    neigh_src = neigs->ExistNeighbourMac(source_mac);
    neigh_dst = neigs->ExistNeighbourMac(destination_mac);

if (isInterestingPacket(source_ip, source_mac, destination_ip, destination_mac)) {
/* If the destination IP is different of the destination neighbour, means that must be forwarded */
if (neigh_dst != NULL && (neigh_dst->ip != 666) && (destination_ip != neigh_dst->ip)) {
            neigs->ShowAllNeighbours();
waitingForwardPacket(source_ip, destination_ip, sourcePort, destinationPort, tmp_data, data_size, neigh_dst, protocol, pktime);
        }else{
if(destination_mac!=ownMAC){
                neigs->ShowAllNeighbours();
            }
        }
/* If the IP source is different of the sender, means that is a forwarded packet */
if ((neigh_src != NULL) && (neigh_src->ip != 666)){
if (debug > 2)  printf("Sender: %d Hop: %d Destination: %d\n", source_mac, neigh_src->mac, destination_ip);
if (source_ip != neigh_src->ip) {
packetForwarded(destination_ip, source_ip, tmp_data, data_size, neigh_src, protocol, pktime);
        }}
    }
}

/**
 * A packet has been forwarded, delete it from the waiting forward list.
*/
void
WATCHDOG::packetForwarded(int32_t destination_ip, int32_t source_ip, char *body, int data_size, neighbour *neigh, int protocol, double pktime) {
if (debug > 2) printf("packetForwarded\n");
if (neigh != NULL) {
        neigs->AddNeighbourPacketForwarded(neigh, body, destination_ip, source_ip, data_size, storing_packet_timeout, protocol, pktime);
    }
}

 * Add a packet to a neighbour not forwarded yet.
 */
void
NEIGHBOURS::AddNeighbourPacketForwarded(neighbour *neig, char *body, int32_t ip_dst, int32_t ip_src, int data_size, int storing_time, int protocol, double pktime) {
    neig->time = pktime;
    neig->pckts->AddPacketForwarded(body, ip_dst, ip_src, data_size, storing_time, protocol, pktime);
}

/**
 * Indicates that a new packet forwarded has been listened.
*/
void
PACKETS::AddPacketForwarded( char *body, int32_t ip_dst, int32_t ip_src, int data_size, int storing_time, int protocol, double pktime) {
    packet * exists;
    exists = ExistsPacket(body, ip_dst, ip_src, data_size, storing_time, protocol, pktime);
if (exists != NULL) {
 pckts->forwarded_packets[protocol]++;
 RemovePacket(exists, protocol);
    }
}

/**
 * Delete a stored packet.
*/
void
PACKETS::RemovePacket( packet *pk, int protocol) {
    packet *next, *prev;
if (pk != NULL) {
        next = pk->next;
        prev = pk->previous;

/* is the first packet */
if (pk == pckts->packets[protocol]) {
            pckts->packets[protocol] = pk->next;
        }

/* is the last packet */
if (pk == pckts->last_packet[protocol]) {
            pckts->last_packet[protocol] = pk->previous;
        }

if (next != NULL) next->previous = prev;
if (prev != NULL) prev->next = next;

        pckts->stored_packets--;
        pckts->stored_packets_protocol[protocol] = pckts->stored_packets_protocol[protocol] - (1 / pk->devalue);
        DeletePacket(pk);
        pk = NULL;

    } else {
        printf("This packet does not exists!\n");
    }
}

转载于:https://www.cnblogs.com/zhangrui/archive/2012/03/08/2385236.html