dhcp-ip.c

this is sample about DHCP-agent

/* $Header: /cvsroot/dhcp-agent/dhcp-agent/src/dhcp-ip.c,v 1.5 2002/12/27 02:53:45 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.
 * 
 * IP object.
 * 
 */

#define MODULE_NAME "dhcp-ip"

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

#include "dhcp-align.h"

ip_obj *ip_create(void)
{
    ip_obj *ip;

    ip = xmalloc(sizeof(ip_obj));
    ip->header.ip_v = 4; /* this won't ever be changed. */

    return ip;
}

void ip_destroy(ip_obj * ip)
{
    xfree(ip);
}

ip_addr_t ip_get_src_addr(ip_obj * ip)
{
    return (ip->header.ip_src);
}

ip_addr_t ip_get_dst_addr(ip_obj * ip)
{
    return (ip->header.ip_dst);
}

unsigned char ip_get_hl(ip_obj * ip)
{
    return (ip->header.ip_hl * 4);
}

uint8_t ip_get_proto(ip_obj * ip)
{
    return (ip->header.ip_p);
}

void ip_set_src_addr(ip_obj * ip, uint32_t ip_src)
{
    ip->header.ip_src = ip_src;
    return;
}

void ip_set_dst_addr(ip_obj * ip, uint32_t ip_dst)
{
    ip->header.ip_dst = ip_dst;
    return;
}

void ip_set_hl(ip_obj * ip, uint16_t header_len)
{
    unsigned char ip_hl;

    ip_hl = (header_len / 4); /* this is expected to fit. */
    ip->header.ip_hl = ip_hl;
    return;
}

void ip_set_proto(ip_obj * ip, unsigned char ip_proto)
{
    ip->header.ip_p = ip_proto;
    return;
}

void ip_set_tos(ip_obj * ip, unsigned char ip_tos)
{
    ip->header.ip_tos = ip_tos;
    return;
}

void ip_set_len(ip_obj * ip, uint16_t ip_len)
{
    ip->header.ip_len = htons(ip_len);
    return;
}

void ip_set_id(ip_obj * ip, uint16_t ip_id)
{
    ip->header.ip_id = htons(ip_id);
    return;
}

void ip_set_off(ip_obj * ip, uint16_t ip_off)
{
    ip->header.ip_off = htons(ip_off);
    return;
}

void ip_set_ttl(ip_obj * ip, uint8_t ip_ttl)
{
    ip->header.ip_ttl = ip_ttl;
    return;
}

int ip_read_packet_image(ip_obj * ip, const unsigned char *packet, int len)
{
    if(len < IP_HDR_LEN)
        return -1;

    align_ip(packet, &ip->header);

    return 0;
}

void ip_write_packet_image(ip_obj * ip, unsigned char *packet)
{
    /* struct may pad. memcpy() each member. */
    unsigned char ipvhl;
    unsigned char hl, v;

    /* grr! */
    hl = ip->header.ip_hl;
    v = ip->header.ip_v;

    ipvhl = (v << 4 | hl);

    *packet = ipvhl;
    packet += sizeof(ipvhl);

    memcpy(packet, &ip->header.ip_tos, sizeof(ip->header.ip_tos));
    packet += sizeof(ip->header.ip_tos);

    memcpy(packet, &ip->header.ip_len, sizeof(ip->header.ip_len));
    packet += sizeof(ip->header.ip_len);

    memcpy(packet, &ip->header.ip_id, sizeof(ip->header.ip_id));
    packet += sizeof(ip->header.ip_id);

    memcpy(packet, &ip->header.ip_off, sizeof(ip->header.ip_off));
    packet += sizeof(ip->header.ip_off);

    memcpy(packet, &ip->header.ip_ttl, sizeof(ip->header.ip_ttl));
    packet += sizeof(ip->header.ip_ttl);

    memcpy(packet, &ip->header.ip_p, sizeof(ip->header.ip_p));
    packet += sizeof(ip->header.ip_p);

    /* skip checksum field. */
    packet += 2;

    memcpy(packet, &ip->header.ip_src, IP_ADDR_LEN);
    packet += IP_ADDR_LEN;

    memcpy(packet, &ip->header.ip_dst, IP_ADDR_LEN);

    return;
}