rip.cpp

互联网RIP协议示例代码

#include "sysinclude.h"

extern void rip_sendIpPkt(unsigned char *pData, UINT16 len,unsigned short dstPort,UINT8 iNo);

extern struct stud_rip_route_node *g_rip_route_table;

typedef struct RIP_header
{
	unsigned char command;
	unsigned char version;
	unsigned short zero;
};

typedef struct RIP_data
{
	unsigned short addrfamilyid;
	unsigned short routetag;
	unsigned int ipaddr;
	unsigned int subnetmask;
	unsigned int nexthop;
	unsigned int metric;
};

void sendPacket( unsigned char version, UINT8 iNo) {
	stud_rip_route_node *p = g_rip_route_table;
	int current_size = 0;
	unsigned char *to_send;
	while( p != NULL ){
		if( p->metric != 16 && p->if_no != iNo){
			if(current_size == 0){
				to_send = new unsigned char[512];
				RIP_header *h = (RIP_header *)to_send;
				h->command = 2;
				h->version = version;
				h->zero = 0;
			}
				
			RIP_data * temp = (RIP_data *)(to_send + sizeof(RIP_header) + current_size * sizeof(RIP_data));
			temp->addrfamilyid = htons(2);
			temp->routetag = 0;
			temp->ipaddr = htonl(p->dest);
			temp->metric = htonl(p->metric);
			temp->subnetmask = htonl(p->mask);
			temp->nexthop = htonl(p->nexthop);
				
			if( version == 1){
				temp->subnetmask = 0;
				temp->nexthop = 0;
			}

			current_size = current_size + 1;				
		}

		p = p->next;
			
		if( current_size == 25 || p == NULL){
			rip_sendIpPkt(to_send, sizeof(RIP_header) + current_size * sizeof(RIP_data), 520, iNo);
			current_size = 0;
		}
	}
}

int stud_rip_packet_recv(char *pBuffer,int bufferSize,UINT8 iNo,UINT32 srcAdd)
{
	RIP_header *head = new RIP_header();
	*head = *((RIP_header *)pBuffer);
	//cout<<(int)head->command<<endl;
	//cout<<(int)head->version<<endl;
	//cout<<(int)head->zero<<endl;
	if( head->command != 1 && head->command != 2 ){
		cout<<"STUD_RIP_TEST_COMMAND_ERROR"<<endl;
		ip_DiscardPkt(&(*pBuffer), STUD_RIP_TEST_COMMAND_ERROR);
	}
	
	if( head->zero != 0 ){
		cout<<"STUD_RIP_TEST_MZERO_ERROR"<<endl;
		ip_DiscardPkt(&(*pBuffer), STUD_RIP_TEST_MZERO_ERROR);
	}

	if( head->version != 1 && head->version != 2 ){
		cout<<"STUD_RIP_TEST_VERSION_ERROR"<<endl;
		ip_DiscardPkt(&(*pBuffer), STUD_RIP_TEST_VERSION_ERROR);
	}
	
	if( head->command == 1 ) {
		//request
		cout<<"REQUEST"<<endl;
		sendPacket( head->version, iNo );
	} else if( head->command == 2 ) {
		//response
		cout<<"RESPONSE"<<endl;
		
		int num = ( bufferSize - sizeof(RIP_header) )/ sizeof(RIP_data);
		RIP_data ** data = new RIP_data* [num];
		RIP_data * temp = new RIP_data();

		for(int i = 0; i < num; i++) {
			temp = (RIP_data *)(pBuffer + sizeof(RIP_header) + i * sizeof(RIP_data));
			data[i] = new RIP_data();
			
			data[i]->ipaddr = ntohl(temp->ipaddr);
			data[i]->subnetmask = ntohl(temp->subnetmask);
			data[i]->nexthop = ntohl(temp->nexthop);
			data[i]->metric = ntohl(temp->metric);

			stud_rip_route_node *p = g_rip_route_table;
			while( p != NULL){
				if( p->dest == data[i]->ipaddr && p->mask == data[i]->subnetmask ) {
					if( p->nexthop == data[i]->nexthop ){
						p->metric = data[i]->metric + 1;
						if( p->metric > 16 )
							p->metric = 16;
					} else {
						if( p->metric > data[i]->metric ){
							p->nexthop = data[i]->nexthop;
							p->metric = data[i]->metric + 1;
							if( p->metric > 16 )
								p->metric = 16;
						}
					}
					break;
				}
				
				p = p->next;
			}
			
			if( p == NULL && data[i]->metric < 15){
				stud_rip_route_node *new_node = new stud_rip_route_node();
				new_node->dest = data[i]->ipaddr;
				new_node->mask = data[i]->subnetmask;
				new_node->nexthop = data[i]->nexthop;
				new_node->metric = data[i]->metric + 1;
				new_node->if_no = iNo;
				new_node->next = g_rip_route_table;
				g_rip_route_table = new_node;
			}
		}
	}
	
	return 0;
}

void stud_rip_route_timeout(UINT32 destAdd, UINT32 mask, unsigned char msgType)
{
	cout<<"TIMEOUT"<<endl;
	if( msgType == RIP_MSG_SEND_ROUTE) {
		sendPacket( 2, 1 );
		sendPacket( 2, 2 );
	}
	else if( msgType == RIP_MSG_DELE_ROUTE ) {
		stud_rip_route_node *p = g_rip_route_table;
		while( p != NULL) {
			if( p->dest == destAdd && p->mask == mask ){
				p->metric = 16;
			}
			p = p->next;
		}
	}
}