header.c

#include "header.h"
#include <assert.h>
#include <string.h>

/* fill header without checksum */
int fill_header(u_short seq, u_short ack, u_short offset, u_short flag, packet_t* packet)
{
        assert(offset<=1024);
        assert(flag==ACK||flag==FIN||flag==(ACK|FIN));
        assert(packet!=0);
        packet->header.seq=seq;
        packet->header.ack=ack;
        packet->header.checksum=0;
        packet->header.offset=offset;
        packet->header.flag=flag;
        return 0;
}

int fill_packet(u_char* src, packet_t* packet, u_short size)
{
        assert(size<=PAYLOAD_SIZE);
        memcpy(packet->payload,src,size);
        return 0;
}

int read_header(header_t * p, packet_t* packet)
{
        header_t * tmp= (header_t*)packet;
        p->seq=tmp->seq;
        p->ack=tmp->ack;
        p->offset=tmp->offset;
        p->flag=tmp->flag;
        return 0;
}

int read_packet(u_char* dest, packet_t* packet, u_short size)
{
        assert(size<=PAYLOAD_SIZE);
        memcpy(dest,packet->payload,size);
        return 0;
}