dhcp-udp.c

this is sample about DHCP-agent

/* $Header: /cvsroot/dhcp-agent/dhcp-agent/src/dhcp-udp.c,v 1.3 2002/11/16 00:23:44 actmodern Exp $
 * Copyright 2002 Thamer Alharbash <[e-mail]>
 * 
 * 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. The names of the authors may not be used to endorse or promote
 * products derived from this software without specific prior
 * written permission.
 * 
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 * 
 */

#define MODULE_NAME "dhcp-udp"

#include "dhcp-local.h"
#include "dhcp-libutil.h"
#include "dhcp-librawnet.h"

#include "dhcp-align.h"

udp_obj *udp_create(void)
{
    udp_obj *udp;

    udp = xmalloc(sizeof(udp_obj));

    return udp;
}

void udp_destroy(udp_obj * udp)
{
    xfree(udp);

    return;
}

int udp_read_packet_image(udp_obj * udp, const unsigned char *packet, int len)
{
    if(len < UDP_HDR_LEN)
        return -1;

    align_udp(packet, &udp->header);

    return 0;
}

/* get routines. */

uint16_t udp_get_src_port(udp_obj * udp)
{
    return ntohs(udp->header.uh_sport);
}

uint16_t udp_get_dst_port(udp_obj * udp)
{
    return ntohs(udp->header.uh_dport);
}

uint16_t udp_get_len(udp_obj * udp)
{
    return ntohs(udp->header.uh_ulen);
}

/* set routines. */

void udp_set_src_port(udp_obj * udp, uint16_t src_port)
{
    udp->header.uh_sport = htons(src_port);
    return;
}

void udp_set_dst_port(udp_obj * udp, uint16_t dst_port)
{
    udp->header.uh_dport = htons(dst_port);
    return;
}

void udp_set_len(udp_obj * udp, uint16_t len)
{
    udp->header.uh_ulen = htons(len);
    return;
}

void udp_set_cksum(udp_obj * udp, uint16_t cksum)
{
    udp->header.uh_sum = htons(cksum);
    return;
}

void udp_write_packet_image(udp_obj * udp, unsigned char *packet)
{

    memcpy(packet, &udp->header.uh_sport, 2);
    packet += 2;

    memcpy(packet, &udp->header.uh_dport, 2);
    packet += 2;

    memcpy(packet, &udp->header.uh_ulen, 2);
    packet += 2;

    memcpy(packet, &udp->header.uh_sum, 2);

    return;
}