#include "net_sys.h"

#include "inet.h"
#include "icmp.h"
#include "ipv4.h"

uint32_t icmp_generic(struct netdev *dev, uint32_t ip, uint8_t type, uint8_t* pos,uint8_t *end)
{
    pos-=4; //we need 32 bytes
    struct icmp_v4 *icmp=pos;
    
    icmp->type=type;
    icmp->code=0;
    icmp->csum=0;
    icmp->csum=checksum(icmp,end-pos);

    return ipv4_generic(dev,ip,IPV4_P_ICMP,pos,end);
}

uint32_t icmp_ping(struct netdev *dev, uint32_t ip, uint16_t* pos,uint32_t *end)
{
    // payload
    for(int i=0;i<64;i++)
    {
	pos--;
	*pos=0xbeef;
    }

    // id and sequence number
    pos-=2; // we need 32 bytes
    struct icmp_v4_echo *ping=pos;
    ping->id=htons(0xabcd); // some random number
    ping->seq=htons(0);     // we just send one single ping with id 1 for now

    return icmp_generic(dev,ip,ICMP_ECHO_REQUEST,pos,end);
}


bool icmp_reply(struct netdev *dev,struct eth_hdr *hdr)
{
    unsigned char tmp[6];
    memcpy(tmp,hdr->dmac,6);
    memcpy(hdr->dmac,hdr->smac,6);
    memcpy(hdr->smac,tmp,6);

    struct ipv4_hdr *ipv4=hdr->payload;


    uint32_t tmp2;
    tmp2=ipv4->saddr;
    ipv4->saddr=ipv4->daddr;
    ipv4->daddr=tmp2;
    uint32_t daddr;		 // destination ip address

    struct icmp_v4 *data=(uint32_t *)ipv4+ipv4->ihl;
    data->type=ICMP_ECHO_REPLY;
    data->csum=0;
    ipv4->csum=0;

    data->csum=(checksum(data,ntohs(ipv4->len)-ipv4->ihl*4));
    ipv4->csum=(checksum(ipv4,ntohs(ipv4->len)));

    dev->transmit(hdr,ntohs(ipv4->len)+14); // 14bytes for link2

    return true;
}

bool icmp_incoming(struct netdev *dev,struct eth_hdr *hdr)
{
    struct ipv4_hdr *ipv4=hdr->payload;
    struct icmp_v4 *data=(uint32_t *)ipv4+ipv4->ihl;

//    klog ("icmp type=%d",data->type);
//    klog ("icmp code=%d",data->code);
//    klog ("icmp csum=0x%04x",ntohs(data->csum));
    data->csum=0;
//    klog("expected checksum = 0x%04X",checksum(data,ntohs(ipv4->len)-ipv4->ihl*4));

    if(data->type==ICMP_ECHO_REQUEST) // echo request
    {
	struct icmp_v4_echo *echo=data->data;
	//klog ("received echo request id=%d, seq=%d, data=%d ",ntohs(echo->id),ntohs(echo->seq),echo->data);
	icmp_reply(dev,hdr); /// TODO watchout that this is the memory managed by the network card we are dealing with!!. fix this later.
    }

    return true;
}